10187 lines
352 KiB
Ada
10187 lines
352 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- C H E C K S --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2016, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING3. If not, go to --
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-- http://www.gnu.org/licenses for a complete copy of the license. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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with Atree; use Atree;
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with Casing; use Casing;
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with Debug; use Debug;
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with Einfo; use Einfo;
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with Elists; use Elists;
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with Eval_Fat; use Eval_Fat;
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with Exp_Ch11; use Exp_Ch11;
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with Exp_Ch2; use Exp_Ch2;
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with Exp_Ch4; use Exp_Ch4;
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with Exp_Pakd; use Exp_Pakd;
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with Exp_Util; use Exp_Util;
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with Expander; use Expander;
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with Freeze; use Freeze;
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with Lib; use Lib;
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with Nlists; use Nlists;
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with Nmake; use Nmake;
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with Opt; use Opt;
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with Output; use Output;
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with Restrict; use Restrict;
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with Rident; use Rident;
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with Rtsfind; use Rtsfind;
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with Sem; use Sem;
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with Sem_Aux; use Sem_Aux;
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with Sem_Ch3; use Sem_Ch3;
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with Sem_Ch8; use Sem_Ch8;
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with Sem_Eval; use Sem_Eval;
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with Sem_Res; use Sem_Res;
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with Sem_Util; use Sem_Util;
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with Sem_Warn; use Sem_Warn;
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with Sinfo; use Sinfo;
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with Sinput; use Sinput;
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with Snames; use Snames;
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with Sprint; use Sprint;
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with Stand; use Stand;
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with Stringt; use Stringt;
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with Targparm; use Targparm;
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with Tbuild; use Tbuild;
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with Ttypes; use Ttypes;
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with Validsw; use Validsw;
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package body Checks is
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-- General note: many of these routines are concerned with generating
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-- checking code to make sure that constraint error is raised at runtime.
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-- Clearly this code is only needed if the expander is active, since
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-- otherwise we will not be generating code or going into the runtime
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-- execution anyway.
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-- We therefore disconnect most of these checks if the expander is
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-- inactive. This has the additional benefit that we do not need to
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-- worry about the tree being messed up by previous errors (since errors
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-- turn off expansion anyway).
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-- There are a few exceptions to the above rule. For instance routines
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-- such as Apply_Scalar_Range_Check that do not insert any code can be
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-- safely called even when the Expander is inactive (but Errors_Detected
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-- is 0). The benefit of executing this code when expansion is off, is
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-- the ability to emit constraint error warning for static expressions
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-- even when we are not generating code.
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-- The above is modified in gnatprove mode to ensure that proper check
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-- flags are always placed, even if expansion is off.
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-------------------------------------
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-- Suppression of Redundant Checks --
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-------------------------------------
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-- This unit implements a limited circuit for removal of redundant
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-- checks. The processing is based on a tracing of simple sequential
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-- flow. For any sequence of statements, we save expressions that are
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-- marked to be checked, and then if the same expression appears later
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-- with the same check, then under certain circumstances, the second
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-- check can be suppressed.
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-- Basically, we can suppress the check if we know for certain that
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-- the previous expression has been elaborated (together with its
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-- check), and we know that the exception frame is the same, and that
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-- nothing has happened to change the result of the exception.
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-- Let us examine each of these three conditions in turn to describe
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-- how we ensure that this condition is met.
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-- First, we need to know for certain that the previous expression has
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-- been executed. This is done principally by the mechanism of calling
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-- Conditional_Statements_Begin at the start of any statement sequence
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-- and Conditional_Statements_End at the end. The End call causes all
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-- checks remembered since the Begin call to be discarded. This does
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-- miss a few cases, notably the case of a nested BEGIN-END block with
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-- no exception handlers. But the important thing is to be conservative.
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-- The other protection is that all checks are discarded if a label
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-- is encountered, since then the assumption of sequential execution
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-- is violated, and we don't know enough about the flow.
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-- Second, we need to know that the exception frame is the same. We
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-- do this by killing all remembered checks when we enter a new frame.
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-- Again, that's over-conservative, but generally the cases we can help
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-- with are pretty local anyway (like the body of a loop for example).
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-- Third, we must be sure to forget any checks which are no longer valid.
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-- This is done by two mechanisms, first the Kill_Checks_Variable call is
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-- used to note any changes to local variables. We only attempt to deal
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-- with checks involving local variables, so we do not need to worry
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-- about global variables. Second, a call to any non-global procedure
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-- causes us to abandon all stored checks, since such a all may affect
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-- the values of any local variables.
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-- The following define the data structures used to deal with remembering
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-- checks so that redundant checks can be eliminated as described above.
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-- Right now, the only expressions that we deal with are of the form of
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-- simple local objects (either declared locally, or IN parameters) or
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-- such objects plus/minus a compile time known constant. We can do
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-- more later on if it seems worthwhile, but this catches many simple
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-- cases in practice.
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-- The following record type reflects a single saved check. An entry
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-- is made in the stack of saved checks if and only if the expression
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-- has been elaborated with the indicated checks.
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type Saved_Check is record
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Killed : Boolean;
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-- Set True if entry is killed by Kill_Checks
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Entity : Entity_Id;
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-- The entity involved in the expression that is checked
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Offset : Uint;
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-- A compile time value indicating the result of adding or
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-- subtracting a compile time value. This value is to be
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-- added to the value of the Entity. A value of zero is
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-- used for the case of a simple entity reference.
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Check_Type : Character;
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-- This is set to 'R' for a range check (in which case Target_Type
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-- is set to the target type for the range check) or to 'O' for an
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-- overflow check (in which case Target_Type is set to Empty).
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Target_Type : Entity_Id;
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-- Used only if Do_Range_Check is set. Records the target type for
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-- the check. We need this, because a check is a duplicate only if
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-- it has the same target type (or more accurately one with a
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-- range that is smaller or equal to the stored target type of a
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-- saved check).
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end record;
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-- The following table keeps track of saved checks. Rather than use an
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-- extensible table, we just use a table of fixed size, and we discard
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-- any saved checks that do not fit. That's very unlikely to happen and
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-- this is only an optimization in any case.
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Saved_Checks : array (Int range 1 .. 200) of Saved_Check;
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-- Array of saved checks
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Num_Saved_Checks : Nat := 0;
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-- Number of saved checks
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-- The following stack keeps track of statement ranges. It is treated
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-- as a stack. When Conditional_Statements_Begin is called, an entry
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-- is pushed onto this stack containing the value of Num_Saved_Checks
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-- at the time of the call. Then when Conditional_Statements_End is
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-- called, this value is popped off and used to reset Num_Saved_Checks.
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-- Note: again, this is a fixed length stack with a size that should
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-- always be fine. If the value of the stack pointer goes above the
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-- limit, then we just forget all saved checks.
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Saved_Checks_Stack : array (Int range 1 .. 100) of Nat;
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Saved_Checks_TOS : Nat := 0;
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-----------------------
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-- Local Subprograms --
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-----------------------
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procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id);
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-- Used to apply arithmetic overflow checks for all cases except operators
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-- on signed arithmetic types in MINIMIZED/ELIMINATED case (for which we
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-- call Apply_Arithmetic_Overflow_Minimized_Eliminated below). N can be a
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-- signed integer arithmetic operator (but not an if or case expression).
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-- It is also called for types other than signed integers.
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procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id);
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-- Used to apply arithmetic overflow checks for the case where the overflow
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-- checking mode is MINIMIZED or ELIMINATED and we have a signed integer
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-- arithmetic op (which includes the case of if and case expressions). Note
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-- that Do_Overflow_Check may or may not be set for node Op. In these modes
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-- we have work to do even if overflow checking is suppressed.
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procedure Apply_Division_Check
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(N : Node_Id;
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Rlo : Uint;
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Rhi : Uint;
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ROK : Boolean);
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-- N is an N_Op_Div, N_Op_Rem, or N_Op_Mod node. This routine applies
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-- division checks as required if the Do_Division_Check flag is set.
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-- Rlo and Rhi give the possible range of the right operand, these values
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-- can be referenced and trusted only if ROK is set True.
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procedure Apply_Float_Conversion_Check
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(Ck_Node : Node_Id;
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Target_Typ : Entity_Id);
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-- The checks on a conversion from a floating-point type to an integer
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-- type are delicate. They have to be performed before conversion, they
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-- have to raise an exception when the operand is a NaN, and rounding must
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-- be taken into account to determine the safe bounds of the operand.
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procedure Apply_Selected_Length_Checks
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(Ck_Node : Node_Id;
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Target_Typ : Entity_Id;
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Source_Typ : Entity_Id;
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Do_Static : Boolean);
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-- This is the subprogram that does all the work for Apply_Length_Check
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-- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as
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-- described for the above routines. The Do_Static flag indicates that
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-- only a static check is to be done.
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procedure Apply_Selected_Range_Checks
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(Ck_Node : Node_Id;
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Target_Typ : Entity_Id;
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Source_Typ : Entity_Id;
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Do_Static : Boolean);
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-- This is the subprogram that does all the work for Apply_Range_Check.
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-- Expr, Target_Typ and Source_Typ are as described for the above
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-- routine. The Do_Static flag indicates that only a static check is
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-- to be done.
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type Check_Type is new Check_Id range Access_Check .. Division_Check;
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function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean;
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-- This function is used to see if an access or division by zero check is
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-- needed. The check is to be applied to a single variable appearing in the
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-- source, and N is the node for the reference. If N is not of this form,
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-- True is returned with no further processing. If N is of the right form,
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-- then further processing determines if the given Check is needed.
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--
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-- The particular circuit is to see if we have the case of a check that is
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-- not needed because it appears in the right operand of a short circuited
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-- conditional where the left operand guards the check. For example:
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--
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-- if Var = 0 or else Q / Var > 12 then
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-- ...
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-- end if;
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--
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-- In this example, the division check is not required. At the same time
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-- we can issue warnings for suspicious use of non-short-circuited forms,
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-- such as:
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--
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-- if Var = 0 or Q / Var > 12 then
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-- ...
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-- end if;
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procedure Find_Check
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(Expr : Node_Id;
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Check_Type : Character;
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Target_Type : Entity_Id;
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Entry_OK : out Boolean;
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Check_Num : out Nat;
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Ent : out Entity_Id;
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Ofs : out Uint);
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-- This routine is used by Enable_Range_Check and Enable_Overflow_Check
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-- to see if a check is of the form for optimization, and if so, to see
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-- if it has already been performed. Expr is the expression to check,
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-- and Check_Type is 'R' for a range check, 'O' for an overflow check.
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-- Target_Type is the target type for a range check, and Empty for an
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-- overflow check. If the entry is not of the form for optimization,
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-- then Entry_OK is set to False, and the remaining out parameters
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-- are undefined. If the entry is OK, then Ent/Ofs are set to the
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-- entity and offset from the expression. Check_Num is the number of
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-- a matching saved entry in Saved_Checks, or zero if no such entry
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-- is located.
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function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id;
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-- If a discriminal is used in constraining a prival, Return reference
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-- to the discriminal of the protected body (which renames the parameter
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-- of the enclosing protected operation). This clumsy transformation is
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-- needed because privals are created too late and their actual subtypes
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-- are not available when analysing the bodies of the protected operations.
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-- This function is called whenever the bound is an entity and the scope
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-- indicates a protected operation. If the bound is an in-parameter of
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-- a protected operation that is not a prival, the function returns the
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-- bound itself.
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-- To be cleaned up???
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function Guard_Access
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(Cond : Node_Id;
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Loc : Source_Ptr;
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Ck_Node : Node_Id) return Node_Id;
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-- In the access type case, guard the test with a test to ensure
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-- that the access value is non-null, since the checks do not
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-- not apply to null access values.
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procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr);
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-- Called by Apply_{Length,Range}_Checks to rewrite the tree with the
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-- Constraint_Error node.
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function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean;
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-- Returns True if node N is for an arithmetic operation with signed
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-- integer operands. This includes unary and binary operators, and also
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-- if and case expression nodes where the dependent expressions are of
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-- a signed integer type. These are the kinds of nodes for which special
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-- handling applies in MINIMIZED or ELIMINATED overflow checking mode.
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function Range_Or_Validity_Checks_Suppressed
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(Expr : Node_Id) return Boolean;
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-- Returns True if either range or validity checks or both are suppressed
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-- for the type of the given expression, or, if the expression is the name
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-- of an entity, if these checks are suppressed for the entity.
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function Selected_Length_Checks
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(Ck_Node : Node_Id;
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Target_Typ : Entity_Id;
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Source_Typ : Entity_Id;
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Warn_Node : Node_Id) return Check_Result;
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-- Like Apply_Selected_Length_Checks, except it doesn't modify
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-- anything, just returns a list of nodes as described in the spec of
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-- this package for the Range_Check function.
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function Selected_Range_Checks
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(Ck_Node : Node_Id;
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Target_Typ : Entity_Id;
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Source_Typ : Entity_Id;
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Warn_Node : Node_Id) return Check_Result;
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-- Like Apply_Selected_Range_Checks, except it doesn't modify anything,
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-- just returns a list of nodes as described in the spec of this package
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-- for the Range_Check function.
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------------------------------
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-- Access_Checks_Suppressed --
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------------------------------
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function Access_Checks_Suppressed (E : Entity_Id) return Boolean is
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begin
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if Present (E) and then Checks_May_Be_Suppressed (E) then
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return Is_Check_Suppressed (E, Access_Check);
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else
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return Scope_Suppress.Suppress (Access_Check);
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end if;
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end Access_Checks_Suppressed;
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-------------------------------------
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-- Accessibility_Checks_Suppressed --
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-------------------------------------
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function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is
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begin
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if Present (E) and then Checks_May_Be_Suppressed (E) then
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return Is_Check_Suppressed (E, Accessibility_Check);
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else
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return Scope_Suppress.Suppress (Accessibility_Check);
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end if;
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end Accessibility_Checks_Suppressed;
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-----------------------------
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-- Activate_Division_Check --
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-----------------------------
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procedure Activate_Division_Check (N : Node_Id) is
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begin
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Set_Do_Division_Check (N, True);
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Possible_Local_Raise (N, Standard_Constraint_Error);
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end Activate_Division_Check;
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-----------------------------
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-- Activate_Overflow_Check --
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-----------------------------
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procedure Activate_Overflow_Check (N : Node_Id) is
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Typ : constant Entity_Id := Etype (N);
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begin
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-- Floating-point case. If Etype is not set (this can happen when we
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-- activate a check on a node that has not yet been analyzed), then
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-- we assume we do not have a floating-point type (as per our spec).
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if Present (Typ) and then Is_Floating_Point_Type (Typ) then
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-- Ignore call if we have no automatic overflow checks on the target
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-- and Check_Float_Overflow mode is not set. These are the cases in
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-- which we expect to generate infinities and NaN's with no check.
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if not (Machine_Overflows_On_Target or Check_Float_Overflow) then
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return;
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-- Ignore for unary operations ("+", "-", abs) since these can never
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-- result in overflow for floating-point cases.
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elsif Nkind (N) in N_Unary_Op then
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return;
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-- Otherwise we will set the flag
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else
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null;
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end if;
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-- Discrete case
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else
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-- Nothing to do for Rem/Mod/Plus (overflow not possible, the check
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-- for zero-divide is a divide check, not an overflow check).
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if Nkind_In (N, N_Op_Rem, N_Op_Mod, N_Op_Plus) then
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return;
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end if;
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end if;
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-- Fall through for cases where we do set the flag
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Set_Do_Overflow_Check (N, True);
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Possible_Local_Raise (N, Standard_Constraint_Error);
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end Activate_Overflow_Check;
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--------------------------
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-- Activate_Range_Check --
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--------------------------
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procedure Activate_Range_Check (N : Node_Id) is
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begin
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Set_Do_Range_Check (N, True);
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Possible_Local_Raise (N, Standard_Constraint_Error);
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end Activate_Range_Check;
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---------------------------------
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-- Alignment_Checks_Suppressed --
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---------------------------------
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function Alignment_Checks_Suppressed (E : Entity_Id) return Boolean is
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begin
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if Present (E) and then Checks_May_Be_Suppressed (E) then
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return Is_Check_Suppressed (E, Alignment_Check);
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else
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return Scope_Suppress.Suppress (Alignment_Check);
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end if;
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end Alignment_Checks_Suppressed;
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----------------------------------
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-- Allocation_Checks_Suppressed --
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----------------------------------
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-- Note: at the current time there are no calls to this function, because
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-- the relevant check is in the run-time, so it is not a check that the
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-- compiler can suppress anyway, but we still have to recognize the check
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-- name Allocation_Check since it is part of the standard.
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function Allocation_Checks_Suppressed (E : Entity_Id) return Boolean is
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begin
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if Present (E) and then Checks_May_Be_Suppressed (E) then
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return Is_Check_Suppressed (E, Allocation_Check);
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else
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return Scope_Suppress.Suppress (Allocation_Check);
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end if;
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end Allocation_Checks_Suppressed;
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|
|
-------------------------
|
|
-- Append_Range_Checks --
|
|
-------------------------
|
|
|
|
procedure Append_Range_Checks
|
|
(Checks : Check_Result;
|
|
Stmts : List_Id;
|
|
Suppress_Typ : Entity_Id;
|
|
Static_Sloc : Source_Ptr;
|
|
Flag_Node : Node_Id)
|
|
is
|
|
Internal_Flag_Node : constant Node_Id := Flag_Node;
|
|
Internal_Static_Sloc : constant Source_Ptr := Static_Sloc;
|
|
|
|
Checks_On : constant Boolean :=
|
|
(not Index_Checks_Suppressed (Suppress_Typ))
|
|
or else (not Range_Checks_Suppressed (Suppress_Typ));
|
|
|
|
begin
|
|
-- For now we just return if Checks_On is false, however this should
|
|
-- be enhanced to check for an always True value in the condition
|
|
-- and to generate a compilation warning???
|
|
|
|
if not Checks_On then
|
|
return;
|
|
end if;
|
|
|
|
for J in 1 .. 2 loop
|
|
exit when No (Checks (J));
|
|
|
|
if Nkind (Checks (J)) = N_Raise_Constraint_Error
|
|
and then Present (Condition (Checks (J)))
|
|
then
|
|
if not Has_Dynamic_Range_Check (Internal_Flag_Node) then
|
|
Append_To (Stmts, Checks (J));
|
|
Set_Has_Dynamic_Range_Check (Internal_Flag_Node);
|
|
end if;
|
|
|
|
else
|
|
Append_To
|
|
(Stmts,
|
|
Make_Raise_Constraint_Error (Internal_Static_Sloc,
|
|
Reason => CE_Range_Check_Failed));
|
|
end if;
|
|
end loop;
|
|
end Append_Range_Checks;
|
|
|
|
------------------------
|
|
-- Apply_Access_Check --
|
|
------------------------
|
|
|
|
procedure Apply_Access_Check (N : Node_Id) is
|
|
P : constant Node_Id := Prefix (N);
|
|
|
|
begin
|
|
-- We do not need checks if we are not generating code (i.e. the
|
|
-- expander is not active). This is not just an optimization, there
|
|
-- are cases (e.g. with pragma Debug) where generating the checks
|
|
-- can cause real trouble).
|
|
|
|
if not Expander_Active then
|
|
return;
|
|
end if;
|
|
|
|
-- No check if short circuiting makes check unnecessary
|
|
|
|
if not Check_Needed (P, Access_Check) then
|
|
return;
|
|
end if;
|
|
|
|
-- No check if accessing the Offset_To_Top component of a dispatch
|
|
-- table. They are safe by construction.
|
|
|
|
if Tagged_Type_Expansion
|
|
and then Present (Etype (P))
|
|
and then RTU_Loaded (Ada_Tags)
|
|
and then RTE_Available (RE_Offset_To_Top_Ptr)
|
|
and then Etype (P) = RTE (RE_Offset_To_Top_Ptr)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise go ahead and install the check
|
|
|
|
Install_Null_Excluding_Check (P);
|
|
end Apply_Access_Check;
|
|
|
|
-------------------------------
|
|
-- Apply_Accessibility_Check --
|
|
-------------------------------
|
|
|
|
procedure Apply_Accessibility_Check
|
|
(N : Node_Id;
|
|
Typ : Entity_Id;
|
|
Insert_Node : Node_Id)
|
|
is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Param_Ent : Entity_Id := Param_Entity (N);
|
|
Param_Level : Node_Id;
|
|
Type_Level : Node_Id;
|
|
|
|
begin
|
|
if Ada_Version >= Ada_2012
|
|
and then not Present (Param_Ent)
|
|
and then Is_Entity_Name (N)
|
|
and then Ekind_In (Entity (N), E_Constant, E_Variable)
|
|
and then Present (Effective_Extra_Accessibility (Entity (N)))
|
|
then
|
|
Param_Ent := Entity (N);
|
|
while Present (Renamed_Object (Param_Ent)) loop
|
|
|
|
-- Renamed_Object must return an Entity_Name here
|
|
-- because of preceding "Present (E_E_A (...))" test.
|
|
|
|
Param_Ent := Entity (Renamed_Object (Param_Ent));
|
|
end loop;
|
|
end if;
|
|
|
|
if Inside_A_Generic then
|
|
return;
|
|
|
|
-- Only apply the run-time check if the access parameter has an
|
|
-- associated extra access level parameter and when the level of the
|
|
-- type is less deep than the level of the access parameter, and
|
|
-- accessibility checks are not suppressed.
|
|
|
|
elsif Present (Param_Ent)
|
|
and then Present (Extra_Accessibility (Param_Ent))
|
|
and then UI_Gt (Object_Access_Level (N),
|
|
Deepest_Type_Access_Level (Typ))
|
|
and then not Accessibility_Checks_Suppressed (Param_Ent)
|
|
and then not Accessibility_Checks_Suppressed (Typ)
|
|
then
|
|
Param_Level :=
|
|
New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc);
|
|
|
|
Type_Level :=
|
|
Make_Integer_Literal (Loc, Deepest_Type_Access_Level (Typ));
|
|
|
|
-- Raise Program_Error if the accessibility level of the access
|
|
-- parameter is deeper than the level of the target access type.
|
|
|
|
Insert_Action (Insert_Node,
|
|
Make_Raise_Program_Error (Loc,
|
|
Condition =>
|
|
Make_Op_Gt (Loc,
|
|
Left_Opnd => Param_Level,
|
|
Right_Opnd => Type_Level),
|
|
Reason => PE_Accessibility_Check_Failed));
|
|
|
|
Analyze_And_Resolve (N);
|
|
end if;
|
|
end Apply_Accessibility_Check;
|
|
|
|
--------------------------------
|
|
-- Apply_Address_Clause_Check --
|
|
--------------------------------
|
|
|
|
procedure Apply_Address_Clause_Check (E : Entity_Id; N : Node_Id) is
|
|
pragma Assert (Nkind (N) = N_Freeze_Entity);
|
|
|
|
AC : constant Node_Id := Address_Clause (E);
|
|
Loc : constant Source_Ptr := Sloc (AC);
|
|
Typ : constant Entity_Id := Etype (E);
|
|
|
|
Expr : Node_Id;
|
|
-- Address expression (not necessarily the same as Aexp, for example
|
|
-- when Aexp is a reference to a constant, in which case Expr gets
|
|
-- reset to reference the value expression of the constant).
|
|
|
|
begin
|
|
-- See if alignment check needed. Note that we never need a check if the
|
|
-- maximum alignment is one, since the check will always succeed.
|
|
|
|
-- Note: we do not check for checks suppressed here, since that check
|
|
-- was done in Sem_Ch13 when the address clause was processed. We are
|
|
-- only called if checks were not suppressed. The reason for this is
|
|
-- that we have to delay the call to Apply_Alignment_Check till freeze
|
|
-- time (so that all types etc are elaborated), but we have to check
|
|
-- the status of check suppressing at the point of the address clause.
|
|
|
|
if No (AC)
|
|
or else not Check_Address_Alignment (AC)
|
|
or else Maximum_Alignment = 1
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Obtain expression from address clause
|
|
|
|
Expr := Address_Value (Expression (AC));
|
|
|
|
-- See if we know that Expr has an acceptable value at compile time. If
|
|
-- it hasn't or we don't know, we defer issuing the warning until the
|
|
-- end of the compilation to take into account back end annotations.
|
|
|
|
if Compile_Time_Known_Value (Expr)
|
|
and then (Known_Alignment (E) or else Known_Alignment (Typ))
|
|
then
|
|
declare
|
|
AL : Uint := Alignment (Typ);
|
|
|
|
begin
|
|
-- The object alignment might be more restrictive than the type
|
|
-- alignment.
|
|
|
|
if Known_Alignment (E) then
|
|
AL := Alignment (E);
|
|
end if;
|
|
|
|
if Expr_Value (Expr) mod AL = 0 then
|
|
return;
|
|
end if;
|
|
end;
|
|
|
|
-- If the expression has the form X'Address, then we can find out if the
|
|
-- object X has an alignment that is compatible with the object E. If it
|
|
-- hasn't or we don't know, we defer issuing the warning until the end
|
|
-- of the compilation to take into account back end annotations.
|
|
|
|
elsif Nkind (Expr) = N_Attribute_Reference
|
|
and then Attribute_Name (Expr) = Name_Address
|
|
and then
|
|
Has_Compatible_Alignment (E, Prefix (Expr), False) = Known_Compatible
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Here we do not know if the value is acceptable. Strictly we don't
|
|
-- have to do anything, since if the alignment is bad, we have an
|
|
-- erroneous program. However we are allowed to check for erroneous
|
|
-- conditions and we decide to do this by default if the check is not
|
|
-- suppressed.
|
|
|
|
-- However, don't do the check if elaboration code is unwanted
|
|
|
|
if Restriction_Active (No_Elaboration_Code) then
|
|
return;
|
|
|
|
-- Generate a check to raise PE if alignment may be inappropriate
|
|
|
|
else
|
|
-- If the original expression is a non-static constant, use the name
|
|
-- of the constant itself rather than duplicating its initialization
|
|
-- expression, which was extracted above.
|
|
|
|
-- Note: Expr is empty if the address-clause is applied to in-mode
|
|
-- actuals (allowed by 13.1(22)).
|
|
|
|
if not Present (Expr)
|
|
or else
|
|
(Is_Entity_Name (Expression (AC))
|
|
and then Ekind (Entity (Expression (AC))) = E_Constant
|
|
and then Nkind (Parent (Entity (Expression (AC)))) =
|
|
N_Object_Declaration)
|
|
then
|
|
Expr := New_Copy_Tree (Expression (AC));
|
|
else
|
|
Remove_Side_Effects (Expr);
|
|
end if;
|
|
|
|
if No (Actions (N)) then
|
|
Set_Actions (N, New_List);
|
|
end if;
|
|
|
|
Prepend_To (Actions (N),
|
|
Make_Raise_Program_Error (Loc,
|
|
Condition =>
|
|
Make_Op_Ne (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Mod (Loc,
|
|
Left_Opnd =>
|
|
Unchecked_Convert_To
|
|
(RTE (RE_Integer_Address), Expr),
|
|
Right_Opnd =>
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix => New_Occurrence_Of (E, Loc),
|
|
Attribute_Name => Name_Alignment)),
|
|
Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
|
|
Reason => PE_Misaligned_Address_Value));
|
|
|
|
Warning_Msg := No_Error_Msg;
|
|
Analyze (First (Actions (N)), Suppress => All_Checks);
|
|
|
|
-- If the above raise action generated a warning message (for example
|
|
-- from Warn_On_Non_Local_Exception mode with the active restriction
|
|
-- No_Exception_Propagation).
|
|
|
|
if Warning_Msg /= No_Error_Msg then
|
|
|
|
-- If the expression has a known at compile time value, then
|
|
-- once we know the alignment of the type, we can check if the
|
|
-- exception will be raised or not, and if not, we don't need
|
|
-- the warning so we will kill the warning later on.
|
|
|
|
if Compile_Time_Known_Value (Expr) then
|
|
Alignment_Warnings.Append
|
|
((E => E, A => Expr_Value (Expr), W => Warning_Msg));
|
|
|
|
-- Add explanation of the warning generated by the check
|
|
|
|
else
|
|
Error_Msg_N
|
|
("\address value may be incompatible with alignment of "
|
|
& "object?X?", AC);
|
|
end if;
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
exception
|
|
|
|
-- If we have some missing run time component in configurable run time
|
|
-- mode then just skip the check (it is not required in any case).
|
|
|
|
when RE_Not_Available =>
|
|
return;
|
|
end Apply_Address_Clause_Check;
|
|
|
|
-------------------------------------
|
|
-- Apply_Arithmetic_Overflow_Check --
|
|
-------------------------------------
|
|
|
|
procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is
|
|
begin
|
|
-- Use old routine in almost all cases (the only case we are treating
|
|
-- specially is the case of a signed integer arithmetic op with the
|
|
-- overflow checking mode set to MINIMIZED or ELIMINATED).
|
|
|
|
if Overflow_Check_Mode = Strict
|
|
or else not Is_Signed_Integer_Arithmetic_Op (N)
|
|
then
|
|
Apply_Arithmetic_Overflow_Strict (N);
|
|
|
|
-- Otherwise use the new routine for the case of a signed integer
|
|
-- arithmetic op, with Do_Overflow_Check set to True, and the checking
|
|
-- mode is MINIMIZED or ELIMINATED.
|
|
|
|
else
|
|
Apply_Arithmetic_Overflow_Minimized_Eliminated (N);
|
|
end if;
|
|
end Apply_Arithmetic_Overflow_Check;
|
|
|
|
--------------------------------------
|
|
-- Apply_Arithmetic_Overflow_Strict --
|
|
--------------------------------------
|
|
|
|
-- This routine is called only if the type is an integer type, and a
|
|
-- software arithmetic overflow check may be needed for op (add, subtract,
|
|
-- or multiply). This check is performed only if Software_Overflow_Checking
|
|
-- is enabled and Do_Overflow_Check is set. In this case we expand the
|
|
-- operation into a more complex sequence of tests that ensures that
|
|
-- overflow is properly caught.
|
|
|
|
-- This is used in CHECKED modes. It is identical to the code for this
|
|
-- cases before the big overflow earthquake, thus ensuring that in this
|
|
-- modes we have compatible behavior (and reliability) to what was there
|
|
-- before. It is also called for types other than signed integers, and if
|
|
-- the Do_Overflow_Check flag is off.
|
|
|
|
-- Note: we also call this routine if we decide in the MINIMIZED case
|
|
-- to give up and just generate an overflow check without any fuss.
|
|
|
|
procedure Apply_Arithmetic_Overflow_Strict (N : Node_Id) is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Typ : constant Entity_Id := Etype (N);
|
|
Rtyp : constant Entity_Id := Root_Type (Typ);
|
|
|
|
begin
|
|
-- Nothing to do if Do_Overflow_Check not set or overflow checks
|
|
-- suppressed.
|
|
|
|
if not Do_Overflow_Check (N) then
|
|
return;
|
|
end if;
|
|
|
|
-- An interesting special case. If the arithmetic operation appears as
|
|
-- the operand of a type conversion:
|
|
|
|
-- type1 (x op y)
|
|
|
|
-- and all the following conditions apply:
|
|
|
|
-- arithmetic operation is for a signed integer type
|
|
-- target type type1 is a static integer subtype
|
|
-- range of x and y are both included in the range of type1
|
|
-- range of x op y is included in the range of type1
|
|
-- size of type1 is at least twice the result size of op
|
|
|
|
-- then we don't do an overflow check in any case. Instead, we transform
|
|
-- the operation so that we end up with:
|
|
|
|
-- type1 (type1 (x) op type1 (y))
|
|
|
|
-- This avoids intermediate overflow before the conversion. It is
|
|
-- explicitly permitted by RM 3.5.4(24):
|
|
|
|
-- For the execution of a predefined operation of a signed integer
|
|
-- type, the implementation need not raise Constraint_Error if the
|
|
-- result is outside the base range of the type, so long as the
|
|
-- correct result is produced.
|
|
|
|
-- It's hard to imagine that any programmer counts on the exception
|
|
-- being raised in this case, and in any case it's wrong coding to
|
|
-- have this expectation, given the RM permission. Furthermore, other
|
|
-- Ada compilers do allow such out of range results.
|
|
|
|
-- Note that we do this transformation even if overflow checking is
|
|
-- off, since this is precisely about giving the "right" result and
|
|
-- avoiding the need for an overflow check.
|
|
|
|
-- Note: this circuit is partially redundant with respect to the similar
|
|
-- processing in Exp_Ch4.Expand_N_Type_Conversion, but the latter deals
|
|
-- with cases that do not come through here. We still need the following
|
|
-- processing even with the Exp_Ch4 code in place, since we want to be
|
|
-- sure not to generate the arithmetic overflow check in these cases
|
|
-- (Exp_Ch4 would have a hard time removing them once generated).
|
|
|
|
if Is_Signed_Integer_Type (Typ)
|
|
and then Nkind (Parent (N)) = N_Type_Conversion
|
|
then
|
|
Conversion_Optimization : declare
|
|
Target_Type : constant Entity_Id :=
|
|
Base_Type (Entity (Subtype_Mark (Parent (N))));
|
|
|
|
Llo, Lhi : Uint;
|
|
Rlo, Rhi : Uint;
|
|
LOK, ROK : Boolean;
|
|
|
|
Vlo : Uint;
|
|
Vhi : Uint;
|
|
VOK : Boolean;
|
|
|
|
Tlo : Uint;
|
|
Thi : Uint;
|
|
|
|
begin
|
|
if Is_Integer_Type (Target_Type)
|
|
and then RM_Size (Root_Type (Target_Type)) >= 2 * RM_Size (Rtyp)
|
|
then
|
|
Tlo := Expr_Value (Type_Low_Bound (Target_Type));
|
|
Thi := Expr_Value (Type_High_Bound (Target_Type));
|
|
|
|
Determine_Range
|
|
(Left_Opnd (N), LOK, Llo, Lhi, Assume_Valid => True);
|
|
Determine_Range
|
|
(Right_Opnd (N), ROK, Rlo, Rhi, Assume_Valid => True);
|
|
|
|
if (LOK and ROK)
|
|
and then Tlo <= Llo and then Lhi <= Thi
|
|
and then Tlo <= Rlo and then Rhi <= Thi
|
|
then
|
|
Determine_Range (N, VOK, Vlo, Vhi, Assume_Valid => True);
|
|
|
|
if VOK and then Tlo <= Vlo and then Vhi <= Thi then
|
|
Rewrite (Left_Opnd (N),
|
|
Make_Type_Conversion (Loc,
|
|
Subtype_Mark => New_Occurrence_Of (Target_Type, Loc),
|
|
Expression => Relocate_Node (Left_Opnd (N))));
|
|
|
|
Rewrite (Right_Opnd (N),
|
|
Make_Type_Conversion (Loc,
|
|
Subtype_Mark => New_Occurrence_Of (Target_Type, Loc),
|
|
Expression => Relocate_Node (Right_Opnd (N))));
|
|
|
|
-- Rewrite the conversion operand so that the original
|
|
-- node is retained, in order to avoid the warning for
|
|
-- redundant conversions in Resolve_Type_Conversion.
|
|
|
|
Rewrite (N, Relocate_Node (N));
|
|
|
|
Set_Etype (N, Target_Type);
|
|
|
|
Analyze_And_Resolve (Left_Opnd (N), Target_Type);
|
|
Analyze_And_Resolve (Right_Opnd (N), Target_Type);
|
|
|
|
-- Given that the target type is twice the size of the
|
|
-- source type, overflow is now impossible, so we can
|
|
-- safely kill the overflow check and return.
|
|
|
|
Set_Do_Overflow_Check (N, False);
|
|
return;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end Conversion_Optimization;
|
|
end if;
|
|
|
|
-- Now see if an overflow check is required
|
|
|
|
declare
|
|
Siz : constant Int := UI_To_Int (Esize (Rtyp));
|
|
Dsiz : constant Int := Siz * 2;
|
|
Opnod : Node_Id;
|
|
Ctyp : Entity_Id;
|
|
Opnd : Node_Id;
|
|
Cent : RE_Id;
|
|
|
|
begin
|
|
-- Skip check if back end does overflow checks, or the overflow flag
|
|
-- is not set anyway, or we are not doing code expansion, or the
|
|
-- parent node is a type conversion whose operand is an arithmetic
|
|
-- operation on signed integers on which the expander can promote
|
|
-- later the operands to type Integer (see Expand_N_Type_Conversion).
|
|
|
|
if Backend_Overflow_Checks_On_Target
|
|
or else not Do_Overflow_Check (N)
|
|
or else not Expander_Active
|
|
or else (Present (Parent (N))
|
|
and then Nkind (Parent (N)) = N_Type_Conversion
|
|
and then Integer_Promotion_Possible (Parent (N)))
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise, generate the full general code for front end overflow
|
|
-- detection, which works by doing arithmetic in a larger type:
|
|
|
|
-- x op y
|
|
|
|
-- is expanded into
|
|
|
|
-- Typ (Checktyp (x) op Checktyp (y));
|
|
|
|
-- where Typ is the type of the original expression, and Checktyp is
|
|
-- an integer type of sufficient length to hold the largest possible
|
|
-- result.
|
|
|
|
-- If the size of check type exceeds the size of Long_Long_Integer,
|
|
-- we use a different approach, expanding to:
|
|
|
|
-- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y)))
|
|
|
|
-- where xxx is Add, Multiply or Subtract as appropriate
|
|
|
|
-- Find check type if one exists
|
|
|
|
if Dsiz <= Standard_Integer_Size then
|
|
Ctyp := Standard_Integer;
|
|
|
|
elsif Dsiz <= Standard_Long_Long_Integer_Size then
|
|
Ctyp := Standard_Long_Long_Integer;
|
|
|
|
-- No check type exists, use runtime call
|
|
|
|
else
|
|
if Nkind (N) = N_Op_Add then
|
|
Cent := RE_Add_With_Ovflo_Check;
|
|
|
|
elsif Nkind (N) = N_Op_Multiply then
|
|
Cent := RE_Multiply_With_Ovflo_Check;
|
|
|
|
else
|
|
pragma Assert (Nkind (N) = N_Op_Subtract);
|
|
Cent := RE_Subtract_With_Ovflo_Check;
|
|
end if;
|
|
|
|
Rewrite (N,
|
|
OK_Convert_To (Typ,
|
|
Make_Function_Call (Loc,
|
|
Name => New_Occurrence_Of (RTE (Cent), Loc),
|
|
Parameter_Associations => New_List (
|
|
OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)),
|
|
OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N))))));
|
|
|
|
Analyze_And_Resolve (N, Typ);
|
|
return;
|
|
end if;
|
|
|
|
-- If we fall through, we have the case where we do the arithmetic
|
|
-- in the next higher type and get the check by conversion. In these
|
|
-- cases Ctyp is set to the type to be used as the check type.
|
|
|
|
Opnod := Relocate_Node (N);
|
|
|
|
Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod));
|
|
|
|
Analyze (Opnd);
|
|
Set_Etype (Opnd, Ctyp);
|
|
Set_Analyzed (Opnd, True);
|
|
Set_Left_Opnd (Opnod, Opnd);
|
|
|
|
Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod));
|
|
|
|
Analyze (Opnd);
|
|
Set_Etype (Opnd, Ctyp);
|
|
Set_Analyzed (Opnd, True);
|
|
Set_Right_Opnd (Opnod, Opnd);
|
|
|
|
-- The type of the operation changes to the base type of the check
|
|
-- type, and we reset the overflow check indication, since clearly no
|
|
-- overflow is possible now that we are using a double length type.
|
|
-- We also set the Analyzed flag to avoid a recursive attempt to
|
|
-- expand the node.
|
|
|
|
Set_Etype (Opnod, Base_Type (Ctyp));
|
|
Set_Do_Overflow_Check (Opnod, False);
|
|
Set_Analyzed (Opnod, True);
|
|
|
|
-- Now build the outer conversion
|
|
|
|
Opnd := OK_Convert_To (Typ, Opnod);
|
|
Analyze (Opnd);
|
|
Set_Etype (Opnd, Typ);
|
|
|
|
-- In the discrete type case, we directly generate the range check
|
|
-- for the outer operand. This range check will implement the
|
|
-- required overflow check.
|
|
|
|
if Is_Discrete_Type (Typ) then
|
|
Rewrite (N, Opnd);
|
|
Generate_Range_Check
|
|
(Expression (N), Typ, CE_Overflow_Check_Failed);
|
|
|
|
-- For other types, we enable overflow checking on the conversion,
|
|
-- after setting the node as analyzed to prevent recursive attempts
|
|
-- to expand the conversion node.
|
|
|
|
else
|
|
Set_Analyzed (Opnd, True);
|
|
Enable_Overflow_Check (Opnd);
|
|
Rewrite (N, Opnd);
|
|
end if;
|
|
|
|
exception
|
|
when RE_Not_Available =>
|
|
return;
|
|
end;
|
|
end Apply_Arithmetic_Overflow_Strict;
|
|
|
|
----------------------------------------------------
|
|
-- Apply_Arithmetic_Overflow_Minimized_Eliminated --
|
|
----------------------------------------------------
|
|
|
|
procedure Apply_Arithmetic_Overflow_Minimized_Eliminated (Op : Node_Id) is
|
|
pragma Assert (Is_Signed_Integer_Arithmetic_Op (Op));
|
|
|
|
Loc : constant Source_Ptr := Sloc (Op);
|
|
P : constant Node_Id := Parent (Op);
|
|
|
|
LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer);
|
|
-- Operands and results are of this type when we convert
|
|
|
|
Result_Type : constant Entity_Id := Etype (Op);
|
|
-- Original result type
|
|
|
|
Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode;
|
|
pragma Assert (Check_Mode in Minimized_Or_Eliminated);
|
|
|
|
Lo, Hi : Uint;
|
|
-- Ranges of values for result
|
|
|
|
begin
|
|
-- Nothing to do if our parent is one of the following:
|
|
|
|
-- Another signed integer arithmetic op
|
|
-- A membership operation
|
|
-- A comparison operation
|
|
|
|
-- In all these cases, we will process at the higher level (and then
|
|
-- this node will be processed during the downwards recursion that
|
|
-- is part of the processing in Minimize_Eliminate_Overflows).
|
|
|
|
if Is_Signed_Integer_Arithmetic_Op (P)
|
|
or else Nkind (P) in N_Membership_Test
|
|
or else Nkind (P) in N_Op_Compare
|
|
|
|
-- This is also true for an alternative in a case expression
|
|
|
|
or else Nkind (P) = N_Case_Expression_Alternative
|
|
|
|
-- This is also true for a range operand in a membership test
|
|
|
|
or else (Nkind (P) = N_Range
|
|
and then Nkind (Parent (P)) in N_Membership_Test)
|
|
then
|
|
-- If_Expressions and Case_Expressions are treated as arithmetic
|
|
-- ops, but if they appear in an assignment or similar contexts
|
|
-- there is no overflow check that starts from that parent node,
|
|
-- so apply check now.
|
|
|
|
if Nkind_In (P, N_If_Expression, N_Case_Expression)
|
|
and then not Is_Signed_Integer_Arithmetic_Op (Parent (P))
|
|
then
|
|
null;
|
|
else
|
|
return;
|
|
end if;
|
|
end if;
|
|
|
|
-- Otherwise, we have a top level arithmetic operation node, and this
|
|
-- is where we commence the special processing for MINIMIZED/ELIMINATED
|
|
-- modes. This is the case where we tell the machinery not to move into
|
|
-- Bignum mode at this top level (of course the top level operation
|
|
-- will still be in Bignum mode if either of its operands are of type
|
|
-- Bignum).
|
|
|
|
Minimize_Eliminate_Overflows (Op, Lo, Hi, Top_Level => True);
|
|
|
|
-- That call may but does not necessarily change the result type of Op.
|
|
-- It is the job of this routine to undo such changes, so that at the
|
|
-- top level, we have the proper type. This "undoing" is a point at
|
|
-- which a final overflow check may be applied.
|
|
|
|
-- If the result type was not fiddled we are all set. We go to base
|
|
-- types here because things may have been rewritten to generate the
|
|
-- base type of the operand types.
|
|
|
|
if Base_Type (Etype (Op)) = Base_Type (Result_Type) then
|
|
return;
|
|
|
|
-- Bignum case
|
|
|
|
elsif Is_RTE (Etype (Op), RE_Bignum) then
|
|
|
|
-- We need a sequence that looks like:
|
|
|
|
-- Rnn : Result_Type;
|
|
|
|
-- declare
|
|
-- M : Mark_Id := SS_Mark;
|
|
-- begin
|
|
-- Rnn := Long_Long_Integer'Base (From_Bignum (Op));
|
|
-- SS_Release (M);
|
|
-- end;
|
|
|
|
-- This block is inserted (using Insert_Actions), and then the node
|
|
-- is replaced with a reference to Rnn.
|
|
|
|
-- If our parent is a conversion node then there is no point in
|
|
-- generating a conversion to Result_Type. Instead, we let the parent
|
|
-- handle this. Note that this special case is not just about
|
|
-- optimization. Consider
|
|
|
|
-- A,B,C : Integer;
|
|
-- ...
|
|
-- X := Long_Long_Integer'Base (A * (B ** C));
|
|
|
|
-- Now the product may fit in Long_Long_Integer but not in Integer.
|
|
-- In MINIMIZED/ELIMINATED mode, we don't want to introduce an
|
|
-- overflow exception for this intermediate value.
|
|
|
|
declare
|
|
Blk : constant Node_Id := Make_Bignum_Block (Loc);
|
|
Rnn : constant Entity_Id := Make_Temporary (Loc, 'R', Op);
|
|
RHS : Node_Id;
|
|
|
|
Rtype : Entity_Id;
|
|
|
|
begin
|
|
RHS := Convert_From_Bignum (Op);
|
|
|
|
if Nkind (P) /= N_Type_Conversion then
|
|
Convert_To_And_Rewrite (Result_Type, RHS);
|
|
Rtype := Result_Type;
|
|
|
|
-- Interesting question, do we need a check on that conversion
|
|
-- operation. Answer, not if we know the result is in range.
|
|
-- At the moment we are not taking advantage of this. To be
|
|
-- looked at later ???
|
|
|
|
else
|
|
Rtype := LLIB;
|
|
end if;
|
|
|
|
Insert_Before
|
|
(First (Statements (Handled_Statement_Sequence (Blk))),
|
|
Make_Assignment_Statement (Loc,
|
|
Name => New_Occurrence_Of (Rnn, Loc),
|
|
Expression => RHS));
|
|
|
|
Insert_Actions (Op, New_List (
|
|
Make_Object_Declaration (Loc,
|
|
Defining_Identifier => Rnn,
|
|
Object_Definition => New_Occurrence_Of (Rtype, Loc)),
|
|
Blk));
|
|
|
|
Rewrite (Op, New_Occurrence_Of (Rnn, Loc));
|
|
Analyze_And_Resolve (Op);
|
|
end;
|
|
|
|
-- Here we know the result is Long_Long_Integer'Base, or that it has
|
|
-- been rewritten because the parent operation is a conversion. See
|
|
-- Apply_Arithmetic_Overflow_Strict.Conversion_Optimization.
|
|
|
|
else
|
|
pragma Assert
|
|
(Etype (Op) = LLIB or else Nkind (Parent (Op)) = N_Type_Conversion);
|
|
|
|
-- All we need to do here is to convert the result to the proper
|
|
-- result type. As explained above for the Bignum case, we can
|
|
-- omit this if our parent is a type conversion.
|
|
|
|
if Nkind (P) /= N_Type_Conversion then
|
|
Convert_To_And_Rewrite (Result_Type, Op);
|
|
end if;
|
|
|
|
Analyze_And_Resolve (Op);
|
|
end if;
|
|
end Apply_Arithmetic_Overflow_Minimized_Eliminated;
|
|
|
|
----------------------------
|
|
-- Apply_Constraint_Check --
|
|
----------------------------
|
|
|
|
procedure Apply_Constraint_Check
|
|
(N : Node_Id;
|
|
Typ : Entity_Id;
|
|
No_Sliding : Boolean := False)
|
|
is
|
|
Desig_Typ : Entity_Id;
|
|
|
|
begin
|
|
-- No checks inside a generic (check the instantiations)
|
|
|
|
if Inside_A_Generic then
|
|
return;
|
|
end if;
|
|
|
|
-- Apply required constraint checks
|
|
|
|
if Is_Scalar_Type (Typ) then
|
|
Apply_Scalar_Range_Check (N, Typ);
|
|
|
|
elsif Is_Array_Type (Typ) then
|
|
|
|
-- A useful optimization: an aggregate with only an others clause
|
|
-- always has the right bounds.
|
|
|
|
if Nkind (N) = N_Aggregate
|
|
and then No (Expressions (N))
|
|
and then Nkind
|
|
(First (Choices (First (Component_Associations (N)))))
|
|
= N_Others_Choice
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
if Is_Constrained (Typ) then
|
|
Apply_Length_Check (N, Typ);
|
|
|
|
if No_Sliding then
|
|
Apply_Range_Check (N, Typ);
|
|
end if;
|
|
else
|
|
Apply_Range_Check (N, Typ);
|
|
end if;
|
|
|
|
elsif (Is_Record_Type (Typ) or else Is_Private_Type (Typ))
|
|
and then Has_Discriminants (Base_Type (Typ))
|
|
and then Is_Constrained (Typ)
|
|
then
|
|
Apply_Discriminant_Check (N, Typ);
|
|
|
|
elsif Is_Access_Type (Typ) then
|
|
|
|
Desig_Typ := Designated_Type (Typ);
|
|
|
|
-- No checks necessary if expression statically null
|
|
|
|
if Known_Null (N) then
|
|
if Can_Never_Be_Null (Typ) then
|
|
Install_Null_Excluding_Check (N);
|
|
end if;
|
|
|
|
-- No sliding possible on access to arrays
|
|
|
|
elsif Is_Array_Type (Desig_Typ) then
|
|
if Is_Constrained (Desig_Typ) then
|
|
Apply_Length_Check (N, Typ);
|
|
end if;
|
|
|
|
Apply_Range_Check (N, Typ);
|
|
|
|
elsif Has_Discriminants (Base_Type (Desig_Typ))
|
|
and then Is_Constrained (Desig_Typ)
|
|
then
|
|
Apply_Discriminant_Check (N, Typ);
|
|
end if;
|
|
|
|
-- Apply the 2005 Null_Excluding check. Note that we do not apply
|
|
-- this check if the constraint node is illegal, as shown by having
|
|
-- an error posted. This additional guard prevents cascaded errors
|
|
-- and compiler aborts on illegal programs involving Ada 2005 checks.
|
|
|
|
if Can_Never_Be_Null (Typ)
|
|
and then not Can_Never_Be_Null (Etype (N))
|
|
and then not Error_Posted (N)
|
|
then
|
|
Install_Null_Excluding_Check (N);
|
|
end if;
|
|
end if;
|
|
end Apply_Constraint_Check;
|
|
|
|
------------------------------
|
|
-- Apply_Discriminant_Check --
|
|
------------------------------
|
|
|
|
procedure Apply_Discriminant_Check
|
|
(N : Node_Id;
|
|
Typ : Entity_Id;
|
|
Lhs : Node_Id := Empty)
|
|
is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Do_Access : constant Boolean := Is_Access_Type (Typ);
|
|
S_Typ : Entity_Id := Etype (N);
|
|
Cond : Node_Id;
|
|
T_Typ : Entity_Id;
|
|
|
|
function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean;
|
|
-- A heap object with an indefinite subtype is constrained by its
|
|
-- initial value, and assigning to it requires a constraint_check.
|
|
-- The target may be an explicit dereference, or a renaming of one.
|
|
|
|
function Is_Aliased_Unconstrained_Component return Boolean;
|
|
-- It is possible for an aliased component to have a nominal
|
|
-- unconstrained subtype (through instantiation). If this is a
|
|
-- discriminated component assigned in the expansion of an aggregate
|
|
-- in an initialization, the check must be suppressed. This unusual
|
|
-- situation requires a predicate of its own.
|
|
|
|
----------------------------------
|
|
-- Denotes_Explicit_Dereference --
|
|
----------------------------------
|
|
|
|
function Denotes_Explicit_Dereference (Obj : Node_Id) return Boolean is
|
|
begin
|
|
return
|
|
Nkind (Obj) = N_Explicit_Dereference
|
|
or else
|
|
(Is_Entity_Name (Obj)
|
|
and then Present (Renamed_Object (Entity (Obj)))
|
|
and then Nkind (Renamed_Object (Entity (Obj))) =
|
|
N_Explicit_Dereference);
|
|
end Denotes_Explicit_Dereference;
|
|
|
|
----------------------------------------
|
|
-- Is_Aliased_Unconstrained_Component --
|
|
----------------------------------------
|
|
|
|
function Is_Aliased_Unconstrained_Component return Boolean is
|
|
Comp : Entity_Id;
|
|
Pref : Node_Id;
|
|
|
|
begin
|
|
if Nkind (Lhs) /= N_Selected_Component then
|
|
return False;
|
|
else
|
|
Comp := Entity (Selector_Name (Lhs));
|
|
Pref := Prefix (Lhs);
|
|
end if;
|
|
|
|
if Ekind (Comp) /= E_Component
|
|
or else not Is_Aliased (Comp)
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
return not Comes_From_Source (Pref)
|
|
and then In_Instance
|
|
and then not Is_Constrained (Etype (Comp));
|
|
end Is_Aliased_Unconstrained_Component;
|
|
|
|
-- Start of processing for Apply_Discriminant_Check
|
|
|
|
begin
|
|
if Do_Access then
|
|
T_Typ := Designated_Type (Typ);
|
|
else
|
|
T_Typ := Typ;
|
|
end if;
|
|
|
|
-- Nothing to do if discriminant checks are suppressed or else no code
|
|
-- is to be generated
|
|
|
|
if not Expander_Active
|
|
or else Discriminant_Checks_Suppressed (T_Typ)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- No discriminant checks necessary for an access when expression is
|
|
-- statically Null. This is not only an optimization, it is fundamental
|
|
-- because otherwise discriminant checks may be generated in init procs
|
|
-- for types containing an access to a not-yet-frozen record, causing a
|
|
-- deadly forward reference.
|
|
|
|
-- Also, if the expression is of an access type whose designated type is
|
|
-- incomplete, then the access value must be null and we suppress the
|
|
-- check.
|
|
|
|
if Known_Null (N) then
|
|
return;
|
|
|
|
elsif Is_Access_Type (S_Typ) then
|
|
S_Typ := Designated_Type (S_Typ);
|
|
|
|
if Ekind (S_Typ) = E_Incomplete_Type then
|
|
return;
|
|
end if;
|
|
end if;
|
|
|
|
-- If an assignment target is present, then we need to generate the
|
|
-- actual subtype if the target is a parameter or aliased object with
|
|
-- an unconstrained nominal subtype.
|
|
|
|
-- Ada 2005 (AI-363): For Ada 2005, we limit the building of the actual
|
|
-- subtype to the parameter and dereference cases, since other aliased
|
|
-- objects are unconstrained (unless the nominal subtype is explicitly
|
|
-- constrained).
|
|
|
|
if Present (Lhs)
|
|
and then (Present (Param_Entity (Lhs))
|
|
or else (Ada_Version < Ada_2005
|
|
and then not Is_Constrained (T_Typ)
|
|
and then Is_Aliased_View (Lhs)
|
|
and then not Is_Aliased_Unconstrained_Component)
|
|
or else (Ada_Version >= Ada_2005
|
|
and then not Is_Constrained (T_Typ)
|
|
and then Denotes_Explicit_Dereference (Lhs)
|
|
and then Nkind (Original_Node (Lhs)) /=
|
|
N_Function_Call))
|
|
then
|
|
T_Typ := Get_Actual_Subtype (Lhs);
|
|
end if;
|
|
|
|
-- Nothing to do if the type is unconstrained (this is the case where
|
|
-- the actual subtype in the RM sense of N is unconstrained and no check
|
|
-- is required).
|
|
|
|
if not Is_Constrained (T_Typ) then
|
|
return;
|
|
|
|
-- Ada 2005: nothing to do if the type is one for which there is a
|
|
-- partial view that is constrained.
|
|
|
|
elsif Ada_Version >= Ada_2005
|
|
and then Object_Type_Has_Constrained_Partial_View
|
|
(Typ => Base_Type (T_Typ),
|
|
Scop => Current_Scope)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Nothing to do if the type is an Unchecked_Union
|
|
|
|
if Is_Unchecked_Union (Base_Type (T_Typ)) then
|
|
return;
|
|
end if;
|
|
|
|
-- Suppress checks if the subtypes are the same. The check must be
|
|
-- preserved in an assignment to a formal, because the constraint is
|
|
-- given by the actual.
|
|
|
|
if Nkind (Original_Node (N)) /= N_Allocator
|
|
and then (No (Lhs)
|
|
or else not Is_Entity_Name (Lhs)
|
|
or else No (Param_Entity (Lhs)))
|
|
then
|
|
if (Etype (N) = Typ
|
|
or else (Do_Access and then Designated_Type (Typ) = S_Typ))
|
|
and then not Is_Aliased_View (Lhs)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- We can also eliminate checks on allocators with a subtype mark that
|
|
-- coincides with the context type. The context type may be a subtype
|
|
-- without a constraint (common case, a generic actual).
|
|
|
|
elsif Nkind (Original_Node (N)) = N_Allocator
|
|
and then Is_Entity_Name (Expression (Original_Node (N)))
|
|
then
|
|
declare
|
|
Alloc_Typ : constant Entity_Id :=
|
|
Entity (Expression (Original_Node (N)));
|
|
|
|
begin
|
|
if Alloc_Typ = T_Typ
|
|
or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration
|
|
and then Is_Entity_Name (
|
|
Subtype_Indication (Parent (T_Typ)))
|
|
and then Alloc_Typ = Base_Type (T_Typ))
|
|
|
|
then
|
|
return;
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
-- See if we have a case where the types are both constrained, and all
|
|
-- the constraints are constants. In this case, we can do the check
|
|
-- successfully at compile time.
|
|
|
|
-- We skip this check for the case where the node is rewritten as
|
|
-- an allocator, because it already carries the context subtype,
|
|
-- and extracting the discriminants from the aggregate is messy.
|
|
|
|
if Is_Constrained (S_Typ)
|
|
and then Nkind (Original_Node (N)) /= N_Allocator
|
|
then
|
|
declare
|
|
DconT : Elmt_Id;
|
|
Discr : Entity_Id;
|
|
DconS : Elmt_Id;
|
|
ItemS : Node_Id;
|
|
ItemT : Node_Id;
|
|
|
|
begin
|
|
-- S_Typ may not have discriminants in the case where it is a
|
|
-- private type completed by a default discriminated type. In that
|
|
-- case, we need to get the constraints from the underlying type.
|
|
-- If the underlying type is unconstrained (i.e. has no default
|
|
-- discriminants) no check is needed.
|
|
|
|
if Has_Discriminants (S_Typ) then
|
|
Discr := First_Discriminant (S_Typ);
|
|
DconS := First_Elmt (Discriminant_Constraint (S_Typ));
|
|
|
|
else
|
|
Discr := First_Discriminant (Underlying_Type (S_Typ));
|
|
DconS :=
|
|
First_Elmt
|
|
(Discriminant_Constraint (Underlying_Type (S_Typ)));
|
|
|
|
if No (DconS) then
|
|
return;
|
|
end if;
|
|
|
|
-- A further optimization: if T_Typ is derived from S_Typ
|
|
-- without imposing a constraint, no check is needed.
|
|
|
|
if Nkind (Original_Node (Parent (T_Typ))) =
|
|
N_Full_Type_Declaration
|
|
then
|
|
declare
|
|
Type_Def : constant Node_Id :=
|
|
Type_Definition (Original_Node (Parent (T_Typ)));
|
|
begin
|
|
if Nkind (Type_Def) = N_Derived_Type_Definition
|
|
and then Is_Entity_Name (Subtype_Indication (Type_Def))
|
|
and then Entity (Subtype_Indication (Type_Def)) = S_Typ
|
|
then
|
|
return;
|
|
end if;
|
|
end;
|
|
end if;
|
|
end if;
|
|
|
|
-- Constraint may appear in full view of type
|
|
|
|
if Ekind (T_Typ) = E_Private_Subtype
|
|
and then Present (Full_View (T_Typ))
|
|
then
|
|
DconT :=
|
|
First_Elmt (Discriminant_Constraint (Full_View (T_Typ)));
|
|
else
|
|
DconT :=
|
|
First_Elmt (Discriminant_Constraint (T_Typ));
|
|
end if;
|
|
|
|
while Present (Discr) loop
|
|
ItemS := Node (DconS);
|
|
ItemT := Node (DconT);
|
|
|
|
-- For a discriminated component type constrained by the
|
|
-- current instance of an enclosing type, there is no
|
|
-- applicable discriminant check.
|
|
|
|
if Nkind (ItemT) = N_Attribute_Reference
|
|
and then Is_Access_Type (Etype (ItemT))
|
|
and then Is_Entity_Name (Prefix (ItemT))
|
|
and then Is_Type (Entity (Prefix (ItemT)))
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- If the expressions for the discriminants are identical
|
|
-- and it is side-effect free (for now just an entity),
|
|
-- this may be a shared constraint, e.g. from a subtype
|
|
-- without a constraint introduced as a generic actual.
|
|
-- Examine other discriminants if any.
|
|
|
|
if ItemS = ItemT
|
|
and then Is_Entity_Name (ItemS)
|
|
then
|
|
null;
|
|
|
|
elsif not Is_OK_Static_Expression (ItemS)
|
|
or else not Is_OK_Static_Expression (ItemT)
|
|
then
|
|
exit;
|
|
|
|
elsif Expr_Value (ItemS) /= Expr_Value (ItemT) then
|
|
if Do_Access then -- needs run-time check.
|
|
exit;
|
|
else
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "incorrect value for discriminant&??",
|
|
CE_Discriminant_Check_Failed, Ent => Discr);
|
|
return;
|
|
end if;
|
|
end if;
|
|
|
|
Next_Elmt (DconS);
|
|
Next_Elmt (DconT);
|
|
Next_Discriminant (Discr);
|
|
end loop;
|
|
|
|
if No (Discr) then
|
|
return;
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
-- Here we need a discriminant check. First build the expression
|
|
-- for the comparisons of the discriminants:
|
|
|
|
-- (n.disc1 /= typ.disc1) or else
|
|
-- (n.disc2 /= typ.disc2) or else
|
|
-- ...
|
|
-- (n.discn /= typ.discn)
|
|
|
|
Cond := Build_Discriminant_Checks (N, T_Typ);
|
|
|
|
-- If Lhs is set and is a parameter, then the condition is guarded by:
|
|
-- lhs'constrained and then (condition built above)
|
|
|
|
if Present (Param_Entity (Lhs)) then
|
|
Cond :=
|
|
Make_And_Then (Loc,
|
|
Left_Opnd =>
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc),
|
|
Attribute_Name => Name_Constrained),
|
|
Right_Opnd => Cond);
|
|
end if;
|
|
|
|
if Do_Access then
|
|
Cond := Guard_Access (Cond, Loc, N);
|
|
end if;
|
|
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition => Cond,
|
|
Reason => CE_Discriminant_Check_Failed));
|
|
end Apply_Discriminant_Check;
|
|
|
|
-------------------------
|
|
-- Apply_Divide_Checks --
|
|
-------------------------
|
|
|
|
procedure Apply_Divide_Checks (N : Node_Id) is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Typ : constant Entity_Id := Etype (N);
|
|
Left : constant Node_Id := Left_Opnd (N);
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
|
|
Mode : constant Overflow_Mode_Type := Overflow_Check_Mode;
|
|
-- Current overflow checking mode
|
|
|
|
LLB : Uint;
|
|
Llo : Uint;
|
|
Lhi : Uint;
|
|
LOK : Boolean;
|
|
Rlo : Uint;
|
|
Rhi : Uint;
|
|
ROK : Boolean;
|
|
|
|
pragma Warnings (Off, Lhi);
|
|
-- Don't actually use this value
|
|
|
|
begin
|
|
-- If we are operating in MINIMIZED or ELIMINATED mode, and we are
|
|
-- operating on signed integer types, then the only thing this routine
|
|
-- does is to call Apply_Arithmetic_Overflow_Minimized_Eliminated. That
|
|
-- procedure will (possibly later on during recursive downward calls),
|
|
-- ensure that any needed overflow/division checks are properly applied.
|
|
|
|
if Mode in Minimized_Or_Eliminated
|
|
and then Is_Signed_Integer_Type (Typ)
|
|
then
|
|
Apply_Arithmetic_Overflow_Minimized_Eliminated (N);
|
|
return;
|
|
end if;
|
|
|
|
-- Proceed here in SUPPRESSED or CHECKED modes
|
|
|
|
if Expander_Active
|
|
and then not Backend_Divide_Checks_On_Target
|
|
and then Check_Needed (Right, Division_Check)
|
|
then
|
|
Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True);
|
|
|
|
-- Deal with division check
|
|
|
|
if Do_Division_Check (N)
|
|
and then not Division_Checks_Suppressed (Typ)
|
|
then
|
|
Apply_Division_Check (N, Rlo, Rhi, ROK);
|
|
end if;
|
|
|
|
-- Deal with overflow check
|
|
|
|
if Do_Overflow_Check (N)
|
|
and then not Overflow_Checks_Suppressed (Etype (N))
|
|
then
|
|
Set_Do_Overflow_Check (N, False);
|
|
|
|
-- Test for extremely annoying case of xxx'First divided by -1
|
|
-- for division of signed integer types (only overflow case).
|
|
|
|
if Nkind (N) = N_Op_Divide
|
|
and then Is_Signed_Integer_Type (Typ)
|
|
then
|
|
Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True);
|
|
LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ)));
|
|
|
|
if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi))
|
|
and then
|
|
((not LOK) or else (Llo = LLB))
|
|
then
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_And_Then (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Eq (Loc,
|
|
Left_Opnd =>
|
|
Duplicate_Subexpr_Move_Checks (Left),
|
|
Right_Opnd => Make_Integer_Literal (Loc, LLB)),
|
|
|
|
Right_Opnd =>
|
|
Make_Op_Eq (Loc,
|
|
Left_Opnd => Duplicate_Subexpr (Right),
|
|
Right_Opnd => Make_Integer_Literal (Loc, -1))),
|
|
|
|
Reason => CE_Overflow_Check_Failed));
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end Apply_Divide_Checks;
|
|
|
|
--------------------------
|
|
-- Apply_Division_Check --
|
|
--------------------------
|
|
|
|
procedure Apply_Division_Check
|
|
(N : Node_Id;
|
|
Rlo : Uint;
|
|
Rhi : Uint;
|
|
ROK : Boolean)
|
|
is
|
|
pragma Assert (Do_Division_Check (N));
|
|
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
|
|
begin
|
|
if Expander_Active
|
|
and then not Backend_Divide_Checks_On_Target
|
|
and then Check_Needed (Right, Division_Check)
|
|
then
|
|
-- See if division by zero possible, and if so generate test. This
|
|
-- part of the test is not controlled by the -gnato switch, since
|
|
-- it is a Division_Check and not an Overflow_Check.
|
|
|
|
if Do_Division_Check (N) then
|
|
Set_Do_Division_Check (N, False);
|
|
|
|
if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Op_Eq (Loc,
|
|
Left_Opnd => Duplicate_Subexpr_Move_Checks (Right),
|
|
Right_Opnd => Make_Integer_Literal (Loc, 0)),
|
|
Reason => CE_Divide_By_Zero));
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end Apply_Division_Check;
|
|
|
|
----------------------------------
|
|
-- Apply_Float_Conversion_Check --
|
|
----------------------------------
|
|
|
|
-- Let F and I be the source and target types of the conversion. The RM
|
|
-- specifies that a floating-point value X is rounded to the nearest
|
|
-- integer, with halfway cases being rounded away from zero. The rounded
|
|
-- value of X is checked against I'Range.
|
|
|
|
-- The catch in the above paragraph is that there is no good way to know
|
|
-- whether the round-to-integer operation resulted in overflow. A remedy is
|
|
-- to perform a range check in the floating-point domain instead, however:
|
|
|
|
-- (1) The bounds may not be known at compile time
|
|
-- (2) The check must take into account rounding or truncation.
|
|
-- (3) The range of type I may not be exactly representable in F.
|
|
-- (4) For the rounding case, The end-points I'First - 0.5 and
|
|
-- I'Last + 0.5 may or may not be in range, depending on the
|
|
-- sign of I'First and I'Last.
|
|
-- (5) X may be a NaN, which will fail any comparison
|
|
|
|
-- The following steps correctly convert X with rounding:
|
|
|
|
-- (1) If either I'First or I'Last is not known at compile time, use
|
|
-- I'Base instead of I in the next three steps and perform a
|
|
-- regular range check against I'Range after conversion.
|
|
-- (2) If I'First - 0.5 is representable in F then let Lo be that
|
|
-- value and define Lo_OK as (I'First > 0). Otherwise, let Lo be
|
|
-- F'Machine (I'First) and let Lo_OK be (Lo >= I'First).
|
|
-- In other words, take one of the closest floating-point numbers
|
|
-- (which is an integer value) to I'First, and see if it is in
|
|
-- range or not.
|
|
-- (3) If I'Last + 0.5 is representable in F then let Hi be that value
|
|
-- and define Hi_OK as (I'Last < 0). Otherwise, let Hi be
|
|
-- F'Machine (I'Last) and let Hi_OK be (Hi <= I'Last).
|
|
-- (4) Raise CE when (Lo_OK and X < Lo) or (not Lo_OK and X <= Lo)
|
|
-- or (Hi_OK and X > Hi) or (not Hi_OK and X >= Hi)
|
|
|
|
-- For the truncating case, replace steps (2) and (3) as follows:
|
|
-- (2) If I'First > 0, then let Lo be F'Pred (I'First) and let Lo_OK
|
|
-- be False. Otherwise, let Lo be F'Succ (I'First - 1) and let
|
|
-- Lo_OK be True.
|
|
-- (3) If I'Last < 0, then let Hi be F'Succ (I'Last) and let Hi_OK
|
|
-- be False. Otherwise let Hi be F'Pred (I'Last + 1) and let
|
|
-- Hi_OK be True.
|
|
|
|
procedure Apply_Float_Conversion_Check
|
|
(Ck_Node : Node_Id;
|
|
Target_Typ : Entity_Id)
|
|
is
|
|
LB : constant Node_Id := Type_Low_Bound (Target_Typ);
|
|
HB : constant Node_Id := Type_High_Bound (Target_Typ);
|
|
Loc : constant Source_Ptr := Sloc (Ck_Node);
|
|
Expr_Type : constant Entity_Id := Base_Type (Etype (Ck_Node));
|
|
Target_Base : constant Entity_Id :=
|
|
Implementation_Base_Type (Target_Typ);
|
|
|
|
Par : constant Node_Id := Parent (Ck_Node);
|
|
pragma Assert (Nkind (Par) = N_Type_Conversion);
|
|
-- Parent of check node, must be a type conversion
|
|
|
|
Truncate : constant Boolean := Float_Truncate (Par);
|
|
Max_Bound : constant Uint :=
|
|
UI_Expon
|
|
(Machine_Radix_Value (Expr_Type),
|
|
Machine_Mantissa_Value (Expr_Type) - 1) - 1;
|
|
|
|
-- Largest bound, so bound plus or minus half is a machine number of F
|
|
|
|
Ifirst, Ilast : Uint;
|
|
-- Bounds of integer type
|
|
|
|
Lo, Hi : Ureal;
|
|
-- Bounds to check in floating-point domain
|
|
|
|
Lo_OK, Hi_OK : Boolean;
|
|
-- True iff Lo resp. Hi belongs to I'Range
|
|
|
|
Lo_Chk, Hi_Chk : Node_Id;
|
|
-- Expressions that are False iff check fails
|
|
|
|
Reason : RT_Exception_Code;
|
|
|
|
begin
|
|
-- We do not need checks if we are not generating code (i.e. the full
|
|
-- expander is not active). In SPARK mode, we specifically don't want
|
|
-- the frontend to expand these checks, which are dealt with directly
|
|
-- in the formal verification backend.
|
|
|
|
if not Expander_Active then
|
|
return;
|
|
end if;
|
|
|
|
if not Compile_Time_Known_Value (LB)
|
|
or not Compile_Time_Known_Value (HB)
|
|
then
|
|
declare
|
|
-- First check that the value falls in the range of the base type,
|
|
-- to prevent overflow during conversion and then perform a
|
|
-- regular range check against the (dynamic) bounds.
|
|
|
|
pragma Assert (Target_Base /= Target_Typ);
|
|
|
|
Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Par);
|
|
|
|
begin
|
|
Apply_Float_Conversion_Check (Ck_Node, Target_Base);
|
|
Set_Etype (Temp, Target_Base);
|
|
|
|
Insert_Action (Parent (Par),
|
|
Make_Object_Declaration (Loc,
|
|
Defining_Identifier => Temp,
|
|
Object_Definition => New_Occurrence_Of (Target_Typ, Loc),
|
|
Expression => New_Copy_Tree (Par)),
|
|
Suppress => All_Checks);
|
|
|
|
Insert_Action (Par,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Not_In (Loc,
|
|
Left_Opnd => New_Occurrence_Of (Temp, Loc),
|
|
Right_Opnd => New_Occurrence_Of (Target_Typ, Loc)),
|
|
Reason => CE_Range_Check_Failed));
|
|
Rewrite (Par, New_Occurrence_Of (Temp, Loc));
|
|
|
|
return;
|
|
end;
|
|
end if;
|
|
|
|
-- Get the (static) bounds of the target type
|
|
|
|
Ifirst := Expr_Value (LB);
|
|
Ilast := Expr_Value (HB);
|
|
|
|
-- A simple optimization: if the expression is a universal literal,
|
|
-- we can do the comparison with the bounds and the conversion to
|
|
-- an integer type statically. The range checks are unchanged.
|
|
|
|
if Nkind (Ck_Node) = N_Real_Literal
|
|
and then Etype (Ck_Node) = Universal_Real
|
|
and then Is_Integer_Type (Target_Typ)
|
|
and then Nkind (Parent (Ck_Node)) = N_Type_Conversion
|
|
then
|
|
declare
|
|
Int_Val : constant Uint := UR_To_Uint (Realval (Ck_Node));
|
|
|
|
begin
|
|
if Int_Val <= Ilast and then Int_Val >= Ifirst then
|
|
|
|
-- Conversion is safe
|
|
|
|
Rewrite (Parent (Ck_Node),
|
|
Make_Integer_Literal (Loc, UI_To_Int (Int_Val)));
|
|
Analyze_And_Resolve (Parent (Ck_Node), Target_Typ);
|
|
return;
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
-- Check against lower bound
|
|
|
|
if Truncate and then Ifirst > 0 then
|
|
Lo := Pred (Expr_Type, UR_From_Uint (Ifirst));
|
|
Lo_OK := False;
|
|
|
|
elsif Truncate then
|
|
Lo := Succ (Expr_Type, UR_From_Uint (Ifirst - 1));
|
|
Lo_OK := True;
|
|
|
|
elsif abs (Ifirst) < Max_Bound then
|
|
Lo := UR_From_Uint (Ifirst) - Ureal_Half;
|
|
Lo_OK := (Ifirst > 0);
|
|
|
|
else
|
|
Lo := Machine (Expr_Type, UR_From_Uint (Ifirst), Round_Even, Ck_Node);
|
|
Lo_OK := (Lo >= UR_From_Uint (Ifirst));
|
|
end if;
|
|
|
|
if Lo_OK then
|
|
|
|
-- Lo_Chk := (X >= Lo)
|
|
|
|
Lo_Chk := Make_Op_Ge (Loc,
|
|
Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
|
|
Right_Opnd => Make_Real_Literal (Loc, Lo));
|
|
|
|
else
|
|
-- Lo_Chk := (X > Lo)
|
|
|
|
Lo_Chk := Make_Op_Gt (Loc,
|
|
Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
|
|
Right_Opnd => Make_Real_Literal (Loc, Lo));
|
|
end if;
|
|
|
|
-- Check against higher bound
|
|
|
|
if Truncate and then Ilast < 0 then
|
|
Hi := Succ (Expr_Type, UR_From_Uint (Ilast));
|
|
Hi_OK := False;
|
|
|
|
elsif Truncate then
|
|
Hi := Pred (Expr_Type, UR_From_Uint (Ilast + 1));
|
|
Hi_OK := True;
|
|
|
|
elsif abs (Ilast) < Max_Bound then
|
|
Hi := UR_From_Uint (Ilast) + Ureal_Half;
|
|
Hi_OK := (Ilast < 0);
|
|
else
|
|
Hi := Machine (Expr_Type, UR_From_Uint (Ilast), Round_Even, Ck_Node);
|
|
Hi_OK := (Hi <= UR_From_Uint (Ilast));
|
|
end if;
|
|
|
|
if Hi_OK then
|
|
|
|
-- Hi_Chk := (X <= Hi)
|
|
|
|
Hi_Chk := Make_Op_Le (Loc,
|
|
Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
|
|
Right_Opnd => Make_Real_Literal (Loc, Hi));
|
|
|
|
else
|
|
-- Hi_Chk := (X < Hi)
|
|
|
|
Hi_Chk := Make_Op_Lt (Loc,
|
|
Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
|
|
Right_Opnd => Make_Real_Literal (Loc, Hi));
|
|
end if;
|
|
|
|
-- If the bounds of the target type are the same as those of the base
|
|
-- type, the check is an overflow check as a range check is not
|
|
-- performed in these cases.
|
|
|
|
if Expr_Value (Type_Low_Bound (Target_Base)) = Ifirst
|
|
and then Expr_Value (Type_High_Bound (Target_Base)) = Ilast
|
|
then
|
|
Reason := CE_Overflow_Check_Failed;
|
|
else
|
|
Reason := CE_Range_Check_Failed;
|
|
end if;
|
|
|
|
-- Raise CE if either conditions does not hold
|
|
|
|
Insert_Action (Ck_Node,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition => Make_Op_Not (Loc, Make_And_Then (Loc, Lo_Chk, Hi_Chk)),
|
|
Reason => Reason));
|
|
end Apply_Float_Conversion_Check;
|
|
|
|
------------------------
|
|
-- Apply_Length_Check --
|
|
------------------------
|
|
|
|
procedure Apply_Length_Check
|
|
(Ck_Node : Node_Id;
|
|
Target_Typ : Entity_Id;
|
|
Source_Typ : Entity_Id := Empty)
|
|
is
|
|
begin
|
|
Apply_Selected_Length_Checks
|
|
(Ck_Node, Target_Typ, Source_Typ, Do_Static => False);
|
|
end Apply_Length_Check;
|
|
|
|
-------------------------------------
|
|
-- Apply_Parameter_Aliasing_Checks --
|
|
-------------------------------------
|
|
|
|
procedure Apply_Parameter_Aliasing_Checks
|
|
(Call : Node_Id;
|
|
Subp : Entity_Id)
|
|
is
|
|
Loc : constant Source_Ptr := Sloc (Call);
|
|
|
|
function May_Cause_Aliasing
|
|
(Formal_1 : Entity_Id;
|
|
Formal_2 : Entity_Id) return Boolean;
|
|
-- Determine whether two formal parameters can alias each other
|
|
-- depending on their modes.
|
|
|
|
function Original_Actual (N : Node_Id) return Node_Id;
|
|
-- The expander may replace an actual with a temporary for the sake of
|
|
-- side effect removal. The temporary may hide a potential aliasing as
|
|
-- it does not share the address of the actual. This routine attempts
|
|
-- to retrieve the original actual.
|
|
|
|
procedure Overlap_Check
|
|
(Actual_1 : Node_Id;
|
|
Actual_2 : Node_Id;
|
|
Formal_1 : Entity_Id;
|
|
Formal_2 : Entity_Id;
|
|
Check : in out Node_Id);
|
|
-- Create a check to determine whether Actual_1 overlaps with Actual_2.
|
|
-- If detailed exception messages are enabled, the check is augmented to
|
|
-- provide information about the names of the corresponding formals. See
|
|
-- the body for details. Actual_1 and Actual_2 denote the two actuals to
|
|
-- be tested. Formal_1 and Formal_2 denote the corresponding formals.
|
|
-- Check contains all and-ed simple tests generated so far or remains
|
|
-- unchanged in the case of detailed exception messaged.
|
|
|
|
------------------------
|
|
-- May_Cause_Aliasing --
|
|
------------------------
|
|
|
|
function May_Cause_Aliasing
|
|
(Formal_1 : Entity_Id;
|
|
Formal_2 : Entity_Id) return Boolean
|
|
is
|
|
begin
|
|
-- The following combination cannot lead to aliasing
|
|
|
|
-- Formal 1 Formal 2
|
|
-- IN IN
|
|
|
|
if Ekind (Formal_1) = E_In_Parameter
|
|
and then
|
|
Ekind (Formal_2) = E_In_Parameter
|
|
then
|
|
return False;
|
|
|
|
-- The following combinations may lead to aliasing
|
|
|
|
-- Formal 1 Formal 2
|
|
-- IN OUT
|
|
-- IN IN OUT
|
|
-- OUT IN
|
|
-- OUT IN OUT
|
|
-- OUT OUT
|
|
|
|
else
|
|
return True;
|
|
end if;
|
|
end May_Cause_Aliasing;
|
|
|
|
---------------------
|
|
-- Original_Actual --
|
|
---------------------
|
|
|
|
function Original_Actual (N : Node_Id) return Node_Id is
|
|
begin
|
|
if Nkind (N) = N_Type_Conversion then
|
|
return Expression (N);
|
|
|
|
-- The expander created a temporary to capture the result of a type
|
|
-- conversion where the expression is the real actual.
|
|
|
|
elsif Nkind (N) = N_Identifier
|
|
and then Present (Original_Node (N))
|
|
and then Nkind (Original_Node (N)) = N_Type_Conversion
|
|
then
|
|
return Expression (Original_Node (N));
|
|
end if;
|
|
|
|
return N;
|
|
end Original_Actual;
|
|
|
|
-------------------
|
|
-- Overlap_Check --
|
|
-------------------
|
|
|
|
procedure Overlap_Check
|
|
(Actual_1 : Node_Id;
|
|
Actual_2 : Node_Id;
|
|
Formal_1 : Entity_Id;
|
|
Formal_2 : Entity_Id;
|
|
Check : in out Node_Id)
|
|
is
|
|
Cond : Node_Id;
|
|
ID_Casing : constant Casing_Type :=
|
|
Identifier_Casing (Source_Index (Current_Sem_Unit));
|
|
|
|
begin
|
|
-- Generate:
|
|
-- Actual_1'Overlaps_Storage (Actual_2)
|
|
|
|
Cond :=
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix => New_Copy_Tree (Original_Actual (Actual_1)),
|
|
Attribute_Name => Name_Overlaps_Storage,
|
|
Expressions =>
|
|
New_List (New_Copy_Tree (Original_Actual (Actual_2))));
|
|
|
|
-- Generate the following check when detailed exception messages are
|
|
-- enabled:
|
|
|
|
-- if Actual_1'Overlaps_Storage (Actual_2) then
|
|
-- raise Program_Error with <detailed message>;
|
|
-- end if;
|
|
|
|
if Exception_Extra_Info then
|
|
Start_String;
|
|
|
|
-- Do not generate location information for internal calls
|
|
|
|
if Comes_From_Source (Call) then
|
|
Store_String_Chars (Build_Location_String (Loc));
|
|
Store_String_Char (' ');
|
|
end if;
|
|
|
|
Store_String_Chars ("aliased parameters, actuals for """);
|
|
|
|
Get_Name_String (Chars (Formal_1));
|
|
Set_Casing (ID_Casing);
|
|
Store_String_Chars (Name_Buffer (1 .. Name_Len));
|
|
|
|
Store_String_Chars (""" and """);
|
|
|
|
Get_Name_String (Chars (Formal_2));
|
|
Set_Casing (ID_Casing);
|
|
Store_String_Chars (Name_Buffer (1 .. Name_Len));
|
|
|
|
Store_String_Chars (""" overlap");
|
|
|
|
Insert_Action (Call,
|
|
Make_If_Statement (Loc,
|
|
Condition => Cond,
|
|
Then_Statements => New_List (
|
|
Make_Raise_Statement (Loc,
|
|
Name =>
|
|
New_Occurrence_Of (Standard_Program_Error, Loc),
|
|
Expression => Make_String_Literal (Loc, End_String)))));
|
|
|
|
-- Create a sequence of overlapping checks by and-ing them all
|
|
-- together.
|
|
|
|
else
|
|
if No (Check) then
|
|
Check := Cond;
|
|
else
|
|
Check :=
|
|
Make_And_Then (Loc,
|
|
Left_Opnd => Check,
|
|
Right_Opnd => Cond);
|
|
end if;
|
|
end if;
|
|
end Overlap_Check;
|
|
|
|
-- Local variables
|
|
|
|
Actual_1 : Node_Id;
|
|
Actual_2 : Node_Id;
|
|
Check : Node_Id;
|
|
Formal_1 : Entity_Id;
|
|
Formal_2 : Entity_Id;
|
|
Orig_Act_1 : Node_Id;
|
|
Orig_Act_2 : Node_Id;
|
|
|
|
-- Start of processing for Apply_Parameter_Aliasing_Checks
|
|
|
|
begin
|
|
Check := Empty;
|
|
|
|
Actual_1 := First_Actual (Call);
|
|
Formal_1 := First_Formal (Subp);
|
|
while Present (Actual_1) and then Present (Formal_1) loop
|
|
Orig_Act_1 := Original_Actual (Actual_1);
|
|
|
|
-- Ensure that the actual is an object that is not passed by value.
|
|
-- Elementary types are always passed by value, therefore actuals of
|
|
-- such types cannot lead to aliasing. An aggregate is an object in
|
|
-- Ada 2012, but an actual that is an aggregate cannot overlap with
|
|
-- another actual. A type that is By_Reference (such as an array of
|
|
-- controlled types) is not subject to the check because any update
|
|
-- will be done in place and a subsequent read will always see the
|
|
-- correct value, see RM 6.2 (12/3).
|
|
|
|
if Nkind (Orig_Act_1) = N_Aggregate
|
|
or else (Nkind (Orig_Act_1) = N_Qualified_Expression
|
|
and then Nkind (Expression (Orig_Act_1)) = N_Aggregate)
|
|
then
|
|
null;
|
|
|
|
elsif Is_Object_Reference (Orig_Act_1)
|
|
and then not Is_Elementary_Type (Etype (Orig_Act_1))
|
|
and then not Is_By_Reference_Type (Etype (Orig_Act_1))
|
|
then
|
|
Actual_2 := Next_Actual (Actual_1);
|
|
Formal_2 := Next_Formal (Formal_1);
|
|
while Present (Actual_2) and then Present (Formal_2) loop
|
|
Orig_Act_2 := Original_Actual (Actual_2);
|
|
|
|
-- The other actual we are testing against must also denote
|
|
-- a non pass-by-value object. Generate the check only when
|
|
-- the mode of the two formals may lead to aliasing.
|
|
|
|
if Is_Object_Reference (Orig_Act_2)
|
|
and then not Is_Elementary_Type (Etype (Orig_Act_2))
|
|
and then May_Cause_Aliasing (Formal_1, Formal_2)
|
|
then
|
|
Overlap_Check
|
|
(Actual_1 => Actual_1,
|
|
Actual_2 => Actual_2,
|
|
Formal_1 => Formal_1,
|
|
Formal_2 => Formal_2,
|
|
Check => Check);
|
|
end if;
|
|
|
|
Next_Actual (Actual_2);
|
|
Next_Formal (Formal_2);
|
|
end loop;
|
|
end if;
|
|
|
|
Next_Actual (Actual_1);
|
|
Next_Formal (Formal_1);
|
|
end loop;
|
|
|
|
-- Place a simple check right before the call
|
|
|
|
if Present (Check) and then not Exception_Extra_Info then
|
|
Insert_Action (Call,
|
|
Make_Raise_Program_Error (Loc,
|
|
Condition => Check,
|
|
Reason => PE_Aliased_Parameters));
|
|
end if;
|
|
end Apply_Parameter_Aliasing_Checks;
|
|
|
|
-------------------------------------
|
|
-- Apply_Parameter_Validity_Checks --
|
|
-------------------------------------
|
|
|
|
procedure Apply_Parameter_Validity_Checks (Subp : Entity_Id) is
|
|
Subp_Decl : Node_Id;
|
|
|
|
procedure Add_Validity_Check
|
|
(Formal : Entity_Id;
|
|
Prag_Nam : Name_Id;
|
|
For_Result : Boolean := False);
|
|
-- Add a single 'Valid[_Scalar] check which verifies the initialization
|
|
-- of Formal. Prag_Nam denotes the pre or post condition pragma name.
|
|
-- Set flag For_Result when to verify the result of a function.
|
|
|
|
------------------------
|
|
-- Add_Validity_Check --
|
|
------------------------
|
|
|
|
procedure Add_Validity_Check
|
|
(Formal : Entity_Id;
|
|
Prag_Nam : Name_Id;
|
|
For_Result : Boolean := False)
|
|
is
|
|
procedure Build_Pre_Post_Condition (Expr : Node_Id);
|
|
-- Create a pre/postcondition pragma that tests expression Expr
|
|
|
|
------------------------------
|
|
-- Build_Pre_Post_Condition --
|
|
------------------------------
|
|
|
|
procedure Build_Pre_Post_Condition (Expr : Node_Id) is
|
|
Loc : constant Source_Ptr := Sloc (Subp);
|
|
Decls : List_Id;
|
|
Prag : Node_Id;
|
|
|
|
begin
|
|
Prag :=
|
|
Make_Pragma (Loc,
|
|
Pragma_Identifier =>
|
|
Make_Identifier (Loc, Prag_Nam),
|
|
Pragma_Argument_Associations => New_List (
|
|
Make_Pragma_Argument_Association (Loc,
|
|
Chars => Name_Check,
|
|
Expression => Expr)));
|
|
|
|
-- Add a message unless exception messages are suppressed
|
|
|
|
if not Exception_Locations_Suppressed then
|
|
Append_To (Pragma_Argument_Associations (Prag),
|
|
Make_Pragma_Argument_Association (Loc,
|
|
Chars => Name_Message,
|
|
Expression =>
|
|
Make_String_Literal (Loc,
|
|
Strval => "failed "
|
|
& Get_Name_String (Prag_Nam)
|
|
& " from "
|
|
& Build_Location_String (Loc))));
|
|
end if;
|
|
|
|
-- Insert the pragma in the tree
|
|
|
|
if Nkind (Parent (Subp_Decl)) = N_Compilation_Unit then
|
|
Add_Global_Declaration (Prag);
|
|
Analyze (Prag);
|
|
|
|
-- PPC pragmas associated with subprogram bodies must be inserted
|
|
-- in the declarative part of the body.
|
|
|
|
elsif Nkind (Subp_Decl) = N_Subprogram_Body then
|
|
Decls := Declarations (Subp_Decl);
|
|
|
|
if No (Decls) then
|
|
Decls := New_List;
|
|
Set_Declarations (Subp_Decl, Decls);
|
|
end if;
|
|
|
|
Prepend_To (Decls, Prag);
|
|
Analyze (Prag);
|
|
|
|
-- For subprogram declarations insert the PPC pragma right after
|
|
-- the declarative node.
|
|
|
|
else
|
|
Insert_After_And_Analyze (Subp_Decl, Prag);
|
|
end if;
|
|
end Build_Pre_Post_Condition;
|
|
|
|
-- Local variables
|
|
|
|
Loc : constant Source_Ptr := Sloc (Subp);
|
|
Typ : constant Entity_Id := Etype (Formal);
|
|
Check : Node_Id;
|
|
Nam : Name_Id;
|
|
|
|
-- Start of processing for Add_Validity_Check
|
|
|
|
begin
|
|
-- For scalars, generate 'Valid test
|
|
|
|
if Is_Scalar_Type (Typ) then
|
|
Nam := Name_Valid;
|
|
|
|
-- For any non-scalar with scalar parts, generate 'Valid_Scalars test
|
|
|
|
elsif Scalar_Part_Present (Typ) then
|
|
Nam := Name_Valid_Scalars;
|
|
|
|
-- No test needed for other cases (no scalars to test)
|
|
|
|
else
|
|
return;
|
|
end if;
|
|
|
|
-- Step 1: Create the expression to verify the validity of the
|
|
-- context.
|
|
|
|
Check := New_Occurrence_Of (Formal, Loc);
|
|
|
|
-- When processing a function result, use 'Result. Generate
|
|
-- Context'Result
|
|
|
|
if For_Result then
|
|
Check :=
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix => Check,
|
|
Attribute_Name => Name_Result);
|
|
end if;
|
|
|
|
-- Generate:
|
|
-- Context['Result]'Valid[_Scalars]
|
|
|
|
Check :=
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix => Check,
|
|
Attribute_Name => Nam);
|
|
|
|
-- Step 2: Create a pre or post condition pragma
|
|
|
|
Build_Pre_Post_Condition (Check);
|
|
end Add_Validity_Check;
|
|
|
|
-- Local variables
|
|
|
|
Formal : Entity_Id;
|
|
Subp_Spec : Node_Id;
|
|
|
|
-- Start of processing for Apply_Parameter_Validity_Checks
|
|
|
|
begin
|
|
-- Extract the subprogram specification and declaration nodes
|
|
|
|
Subp_Spec := Parent (Subp);
|
|
|
|
if Nkind (Subp_Spec) = N_Defining_Program_Unit_Name then
|
|
Subp_Spec := Parent (Subp_Spec);
|
|
end if;
|
|
|
|
Subp_Decl := Parent (Subp_Spec);
|
|
|
|
if not Comes_From_Source (Subp)
|
|
|
|
-- Do not process formal subprograms because the corresponding actual
|
|
-- will receive the proper checks when the instance is analyzed.
|
|
|
|
or else Is_Formal_Subprogram (Subp)
|
|
|
|
-- Do not process imported subprograms since pre and postconditions
|
|
-- are never verified on routines coming from a different language.
|
|
|
|
or else Is_Imported (Subp)
|
|
or else Is_Intrinsic_Subprogram (Subp)
|
|
|
|
-- The PPC pragmas generated by this routine do not correspond to
|
|
-- source aspects, therefore they cannot be applied to abstract
|
|
-- subprograms.
|
|
|
|
or else Nkind (Subp_Decl) = N_Abstract_Subprogram_Declaration
|
|
|
|
-- Do not consider subprogram renaminds because the renamed entity
|
|
-- already has the proper PPC pragmas.
|
|
|
|
or else Nkind (Subp_Decl) = N_Subprogram_Renaming_Declaration
|
|
|
|
-- Do not process null procedures because there is no benefit of
|
|
-- adding the checks to a no action routine.
|
|
|
|
or else (Nkind (Subp_Spec) = N_Procedure_Specification
|
|
and then Null_Present (Subp_Spec))
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Inspect all the formals applying aliasing and scalar initialization
|
|
-- checks where applicable.
|
|
|
|
Formal := First_Formal (Subp);
|
|
while Present (Formal) loop
|
|
|
|
-- Generate the following scalar initialization checks for each
|
|
-- formal parameter:
|
|
|
|
-- mode IN - Pre => Formal'Valid[_Scalars]
|
|
-- mode IN OUT - Pre, Post => Formal'Valid[_Scalars]
|
|
-- mode OUT - Post => Formal'Valid[_Scalars]
|
|
|
|
if Check_Validity_Of_Parameters then
|
|
if Ekind_In (Formal, E_In_Parameter, E_In_Out_Parameter) then
|
|
Add_Validity_Check (Formal, Name_Precondition, False);
|
|
end if;
|
|
|
|
if Ekind_In (Formal, E_In_Out_Parameter, E_Out_Parameter) then
|
|
Add_Validity_Check (Formal, Name_Postcondition, False);
|
|
end if;
|
|
end if;
|
|
|
|
Next_Formal (Formal);
|
|
end loop;
|
|
|
|
-- Generate following scalar initialization check for function result:
|
|
|
|
-- Post => Subp'Result'Valid[_Scalars]
|
|
|
|
if Check_Validity_Of_Parameters and then Ekind (Subp) = E_Function then
|
|
Add_Validity_Check (Subp, Name_Postcondition, True);
|
|
end if;
|
|
end Apply_Parameter_Validity_Checks;
|
|
|
|
---------------------------
|
|
-- Apply_Predicate_Check --
|
|
---------------------------
|
|
|
|
procedure Apply_Predicate_Check (N : Node_Id; Typ : Entity_Id) is
|
|
S : Entity_Id;
|
|
|
|
begin
|
|
if Predicate_Checks_Suppressed (Empty) then
|
|
return;
|
|
|
|
elsif Predicates_Ignored (Typ) then
|
|
return;
|
|
|
|
elsif Present (Predicate_Function (Typ)) then
|
|
S := Current_Scope;
|
|
while Present (S) and then not Is_Subprogram (S) loop
|
|
S := Scope (S);
|
|
end loop;
|
|
|
|
-- A predicate check does not apply within internally generated
|
|
-- subprograms, such as TSS functions.
|
|
|
|
if Within_Internal_Subprogram then
|
|
return;
|
|
|
|
-- If the check appears within the predicate function itself, it
|
|
-- means that the user specified a check whose formal is the
|
|
-- predicated subtype itself, rather than some covering type. This
|
|
-- is likely to be a common error, and thus deserves a warning.
|
|
|
|
elsif Present (S) and then S = Predicate_Function (Typ) then
|
|
Error_Msg_N
|
|
("predicate check includes a function call that "
|
|
& "requires a predicate check??", Parent (N));
|
|
Error_Msg_N
|
|
("\this will result in infinite recursion??", Parent (N));
|
|
Insert_Action (N,
|
|
Make_Raise_Storage_Error (Sloc (N),
|
|
Reason => SE_Infinite_Recursion));
|
|
|
|
-- Here for normal case of predicate active
|
|
|
|
else
|
|
-- If the type has a static predicate and the expression is known
|
|
-- at compile time, see if the expression satisfies the predicate.
|
|
|
|
Check_Expression_Against_Static_Predicate (N, Typ);
|
|
|
|
if not Expander_Active then
|
|
return;
|
|
end if;
|
|
|
|
-- For an entity of the type, generate a call to the predicate
|
|
-- function, unless its type is an actual subtype, which is not
|
|
-- visible outside of the enclosing subprogram.
|
|
|
|
if Is_Entity_Name (N)
|
|
and then not Is_Actual_Subtype (Typ)
|
|
then
|
|
Insert_Action (N,
|
|
Make_Predicate_Check
|
|
(Typ, New_Occurrence_Of (Entity (N), Sloc (N))));
|
|
|
|
-- If the expression is not an entity it may have side effects,
|
|
-- and the following call will create an object declaration for
|
|
-- it. We disable checks during its analysis, to prevent an
|
|
-- infinite recursion.
|
|
|
|
else
|
|
Insert_Action (N,
|
|
Make_Predicate_Check
|
|
(Typ, Duplicate_Subexpr (N)), Suppress => All_Checks);
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end Apply_Predicate_Check;
|
|
|
|
-----------------------
|
|
-- Apply_Range_Check --
|
|
-----------------------
|
|
|
|
procedure Apply_Range_Check
|
|
(Ck_Node : Node_Id;
|
|
Target_Typ : Entity_Id;
|
|
Source_Typ : Entity_Id := Empty)
|
|
is
|
|
begin
|
|
Apply_Selected_Range_Checks
|
|
(Ck_Node, Target_Typ, Source_Typ, Do_Static => False);
|
|
end Apply_Range_Check;
|
|
|
|
------------------------------
|
|
-- Apply_Scalar_Range_Check --
|
|
------------------------------
|
|
|
|
-- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check flag
|
|
-- off if it is already set on.
|
|
|
|
procedure Apply_Scalar_Range_Check
|
|
(Expr : Node_Id;
|
|
Target_Typ : Entity_Id;
|
|
Source_Typ : Entity_Id := Empty;
|
|
Fixed_Int : Boolean := False)
|
|
is
|
|
Parnt : constant Node_Id := Parent (Expr);
|
|
S_Typ : Entity_Id;
|
|
Arr : Node_Id := Empty; -- initialize to prevent warning
|
|
Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning
|
|
OK : Boolean;
|
|
|
|
Is_Subscr_Ref : Boolean;
|
|
-- Set true if Expr is a subscript
|
|
|
|
Is_Unconstrained_Subscr_Ref : Boolean;
|
|
-- Set true if Expr is a subscript of an unconstrained array. In this
|
|
-- case we do not attempt to do an analysis of the value against the
|
|
-- range of the subscript, since we don't know the actual subtype.
|
|
|
|
Int_Real : Boolean;
|
|
-- Set to True if Expr should be regarded as a real value even though
|
|
-- the type of Expr might be discrete.
|
|
|
|
procedure Bad_Value (Warn : Boolean := False);
|
|
-- Procedure called if value is determined to be out of range. Warn is
|
|
-- True to force a warning instead of an error, even when SPARK_Mode is
|
|
-- On.
|
|
|
|
---------------
|
|
-- Bad_Value --
|
|
---------------
|
|
|
|
procedure Bad_Value (Warn : Boolean := False) is
|
|
begin
|
|
Apply_Compile_Time_Constraint_Error
|
|
(Expr, "value not in range of}??", CE_Range_Check_Failed,
|
|
Ent => Target_Typ,
|
|
Typ => Target_Typ,
|
|
Warn => Warn);
|
|
end Bad_Value;
|
|
|
|
-- Start of processing for Apply_Scalar_Range_Check
|
|
|
|
begin
|
|
-- Return if check obviously not needed
|
|
|
|
if
|
|
-- Not needed inside generic
|
|
|
|
Inside_A_Generic
|
|
|
|
-- Not needed if previous error
|
|
|
|
or else Target_Typ = Any_Type
|
|
or else Nkind (Expr) = N_Error
|
|
|
|
-- Not needed for non-scalar type
|
|
|
|
or else not Is_Scalar_Type (Target_Typ)
|
|
|
|
-- Not needed if we know node raises CE already
|
|
|
|
or else Raises_Constraint_Error (Expr)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Now, see if checks are suppressed
|
|
|
|
Is_Subscr_Ref :=
|
|
Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component;
|
|
|
|
if Is_Subscr_Ref then
|
|
Arr := Prefix (Parnt);
|
|
Arr_Typ := Get_Actual_Subtype_If_Available (Arr);
|
|
|
|
if Is_Access_Type (Arr_Typ) then
|
|
Arr_Typ := Designated_Type (Arr_Typ);
|
|
end if;
|
|
end if;
|
|
|
|
if not Do_Range_Check (Expr) then
|
|
|
|
-- Subscript reference. Check for Index_Checks suppressed
|
|
|
|
if Is_Subscr_Ref then
|
|
|
|
-- Check array type and its base type
|
|
|
|
if Index_Checks_Suppressed (Arr_Typ)
|
|
or else Index_Checks_Suppressed (Base_Type (Arr_Typ))
|
|
then
|
|
return;
|
|
|
|
-- Check array itself if it is an entity name
|
|
|
|
elsif Is_Entity_Name (Arr)
|
|
and then Index_Checks_Suppressed (Entity (Arr))
|
|
then
|
|
return;
|
|
|
|
-- Check expression itself if it is an entity name
|
|
|
|
elsif Is_Entity_Name (Expr)
|
|
and then Index_Checks_Suppressed (Entity (Expr))
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- All other cases, check for Range_Checks suppressed
|
|
|
|
else
|
|
-- Check target type and its base type
|
|
|
|
if Range_Checks_Suppressed (Target_Typ)
|
|
or else Range_Checks_Suppressed (Base_Type (Target_Typ))
|
|
then
|
|
return;
|
|
|
|
-- Check expression itself if it is an entity name
|
|
|
|
elsif Is_Entity_Name (Expr)
|
|
and then Range_Checks_Suppressed (Entity (Expr))
|
|
then
|
|
return;
|
|
|
|
-- If Expr is part of an assignment statement, then check left
|
|
-- side of assignment if it is an entity name.
|
|
|
|
elsif Nkind (Parnt) = N_Assignment_Statement
|
|
and then Is_Entity_Name (Name (Parnt))
|
|
and then Range_Checks_Suppressed (Entity (Name (Parnt)))
|
|
then
|
|
return;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
|
|
-- Do not set range checks if they are killed
|
|
|
|
if Nkind (Expr) = N_Unchecked_Type_Conversion
|
|
and then Kill_Range_Check (Expr)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Do not set range checks for any values from System.Scalar_Values
|
|
-- since the whole idea of such values is to avoid checking them.
|
|
|
|
if Is_Entity_Name (Expr)
|
|
and then Is_RTU (Scope (Entity (Expr)), System_Scalar_Values)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Now see if we need a check
|
|
|
|
if No (Source_Typ) then
|
|
S_Typ := Etype (Expr);
|
|
else
|
|
S_Typ := Source_Typ;
|
|
end if;
|
|
|
|
if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then
|
|
return;
|
|
end if;
|
|
|
|
Is_Unconstrained_Subscr_Ref :=
|
|
Is_Subscr_Ref and then not Is_Constrained (Arr_Typ);
|
|
|
|
-- Special checks for floating-point type
|
|
|
|
if Is_Floating_Point_Type (S_Typ) then
|
|
|
|
-- Always do a range check if the source type includes infinities and
|
|
-- the target type does not include infinities. We do not do this if
|
|
-- range checks are killed.
|
|
-- If the expression is a literal and the bounds of the type are
|
|
-- static constants it may be possible to optimize the check.
|
|
|
|
if Has_Infinities (S_Typ)
|
|
and then not Has_Infinities (Target_Typ)
|
|
then
|
|
-- If the expression is a literal and the bounds of the type are
|
|
-- static constants it may be possible to optimize the check.
|
|
|
|
if Nkind (Expr) = N_Real_Literal then
|
|
declare
|
|
Tlo : constant Node_Id := Type_Low_Bound (Target_Typ);
|
|
Thi : constant Node_Id := Type_High_Bound (Target_Typ);
|
|
|
|
begin
|
|
if Compile_Time_Known_Value (Tlo)
|
|
and then Compile_Time_Known_Value (Thi)
|
|
and then Expr_Value_R (Expr) >= Expr_Value_R (Tlo)
|
|
and then Expr_Value_R (Expr) <= Expr_Value_R (Thi)
|
|
then
|
|
return;
|
|
else
|
|
Enable_Range_Check (Expr);
|
|
end if;
|
|
end;
|
|
|
|
else
|
|
Enable_Range_Check (Expr);
|
|
end if;
|
|
end if;
|
|
end if;
|
|
|
|
-- Return if we know expression is definitely in the range of the target
|
|
-- type as determined by Determine_Range. Right now we only do this for
|
|
-- discrete types, and not fixed-point or floating-point types.
|
|
|
|
-- The additional less-precise tests below catch these cases
|
|
|
|
-- Note: skip this if we are given a source_typ, since the point of
|
|
-- supplying a Source_Typ is to stop us looking at the expression.
|
|
-- We could sharpen this test to be out parameters only ???
|
|
|
|
if Is_Discrete_Type (Target_Typ)
|
|
and then Is_Discrete_Type (Etype (Expr))
|
|
and then not Is_Unconstrained_Subscr_Ref
|
|
and then No (Source_Typ)
|
|
then
|
|
declare
|
|
Tlo : constant Node_Id := Type_Low_Bound (Target_Typ);
|
|
Thi : constant Node_Id := Type_High_Bound (Target_Typ);
|
|
Lo : Uint;
|
|
Hi : Uint;
|
|
|
|
begin
|
|
if Compile_Time_Known_Value (Tlo)
|
|
and then Compile_Time_Known_Value (Thi)
|
|
then
|
|
declare
|
|
Lov : constant Uint := Expr_Value (Tlo);
|
|
Hiv : constant Uint := Expr_Value (Thi);
|
|
|
|
begin
|
|
-- If range is null, we for sure have a constraint error
|
|
-- (we don't even need to look at the value involved,
|
|
-- since all possible values will raise CE).
|
|
|
|
if Lov > Hiv then
|
|
|
|
-- When SPARK_Mode is On, force a warning instead of
|
|
-- an error in that case, as this likely corresponds
|
|
-- to deactivated code.
|
|
|
|
Bad_Value (Warn => SPARK_Mode = On);
|
|
|
|
-- In GNATprove mode, we enable the range check so that
|
|
-- GNATprove will issue a message if it cannot be proved.
|
|
|
|
if GNATprove_Mode then
|
|
Enable_Range_Check (Expr);
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise determine range of value
|
|
|
|
Determine_Range (Expr, OK, Lo, Hi, Assume_Valid => True);
|
|
|
|
if OK then
|
|
|
|
-- If definitely in range, all OK
|
|
|
|
if Lo >= Lov and then Hi <= Hiv then
|
|
return;
|
|
|
|
-- If definitely not in range, warn
|
|
|
|
elsif Lov > Hi or else Hiv < Lo then
|
|
Bad_Value;
|
|
return;
|
|
|
|
-- Otherwise we don't know
|
|
|
|
else
|
|
null;
|
|
end if;
|
|
end if;
|
|
end;
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
Int_Real :=
|
|
Is_Floating_Point_Type (S_Typ)
|
|
or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int);
|
|
|
|
-- Check if we can determine at compile time whether Expr is in the
|
|
-- range of the target type. Note that if S_Typ is within the bounds
|
|
-- of Target_Typ then this must be the case. This check is meaningful
|
|
-- only if this is not a conversion between integer and real types.
|
|
|
|
if not Is_Unconstrained_Subscr_Ref
|
|
and then Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ)
|
|
and then
|
|
(In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int)
|
|
|
|
-- Also check if the expression itself is in the range of the
|
|
-- target type if it is a known at compile time value. We skip
|
|
-- this test if S_Typ is set since for OUT and IN OUT parameters
|
|
-- the Expr itself is not relevant to the checking.
|
|
|
|
or else
|
|
(No (Source_Typ)
|
|
and then Is_In_Range (Expr, Target_Typ,
|
|
Assume_Valid => True,
|
|
Fixed_Int => Fixed_Int,
|
|
Int_Real => Int_Real)))
|
|
then
|
|
return;
|
|
|
|
elsif Is_Out_Of_Range (Expr, Target_Typ,
|
|
Assume_Valid => True,
|
|
Fixed_Int => Fixed_Int,
|
|
Int_Real => Int_Real)
|
|
then
|
|
Bad_Value;
|
|
return;
|
|
|
|
-- Floating-point case
|
|
-- In the floating-point case, we only do range checks if the type is
|
|
-- constrained. We definitely do NOT want range checks for unconstrained
|
|
-- types, since we want to have infinities, except when
|
|
-- Check_Float_Overflow is set.
|
|
|
|
elsif Is_Floating_Point_Type (S_Typ) then
|
|
if Is_Constrained (S_Typ) or else Check_Float_Overflow then
|
|
Enable_Range_Check (Expr);
|
|
end if;
|
|
|
|
-- For all other cases we enable a range check unconditionally
|
|
|
|
else
|
|
Enable_Range_Check (Expr);
|
|
return;
|
|
end if;
|
|
end Apply_Scalar_Range_Check;
|
|
|
|
----------------------------------
|
|
-- Apply_Selected_Length_Checks --
|
|
----------------------------------
|
|
|
|
procedure Apply_Selected_Length_Checks
|
|
(Ck_Node : Node_Id;
|
|
Target_Typ : Entity_Id;
|
|
Source_Typ : Entity_Id;
|
|
Do_Static : Boolean)
|
|
is
|
|
Cond : Node_Id;
|
|
R_Result : Check_Result;
|
|
R_Cno : Node_Id;
|
|
|
|
Loc : constant Source_Ptr := Sloc (Ck_Node);
|
|
Checks_On : constant Boolean :=
|
|
(not Index_Checks_Suppressed (Target_Typ))
|
|
or else (not Length_Checks_Suppressed (Target_Typ));
|
|
|
|
begin
|
|
-- Note: this means that we lose some useful warnings if the expander
|
|
-- is not active, and we also lose these warnings in SPARK mode ???
|
|
|
|
if not Expander_Active then
|
|
return;
|
|
end if;
|
|
|
|
R_Result :=
|
|
Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty);
|
|
|
|
for J in 1 .. 2 loop
|
|
R_Cno := R_Result (J);
|
|
exit when No (R_Cno);
|
|
|
|
-- A length check may mention an Itype which is attached to a
|
|
-- subsequent node. At the top level in a package this can cause
|
|
-- an order-of-elaboration problem, so we make sure that the itype
|
|
-- is referenced now.
|
|
|
|
if Ekind (Current_Scope) = E_Package
|
|
and then Is_Compilation_Unit (Current_Scope)
|
|
then
|
|
Ensure_Defined (Target_Typ, Ck_Node);
|
|
|
|
if Present (Source_Typ) then
|
|
Ensure_Defined (Source_Typ, Ck_Node);
|
|
|
|
elsif Is_Itype (Etype (Ck_Node)) then
|
|
Ensure_Defined (Etype (Ck_Node), Ck_Node);
|
|
end if;
|
|
end if;
|
|
|
|
-- If the item is a conditional raise of constraint error, then have
|
|
-- a look at what check is being performed and ???
|
|
|
|
if Nkind (R_Cno) = N_Raise_Constraint_Error
|
|
and then Present (Condition (R_Cno))
|
|
then
|
|
Cond := Condition (R_Cno);
|
|
|
|
-- Case where node does not now have a dynamic check
|
|
|
|
if not Has_Dynamic_Length_Check (Ck_Node) then
|
|
|
|
-- If checks are on, just insert the check
|
|
|
|
if Checks_On then
|
|
Insert_Action (Ck_Node, R_Cno);
|
|
|
|
if not Do_Static then
|
|
Set_Has_Dynamic_Length_Check (Ck_Node);
|
|
end if;
|
|
|
|
-- If checks are off, then analyze the length check after
|
|
-- temporarily attaching it to the tree in case the relevant
|
|
-- condition can be evaluated at compile time. We still want a
|
|
-- compile time warning in this case.
|
|
|
|
else
|
|
Set_Parent (R_Cno, Ck_Node);
|
|
Analyze (R_Cno);
|
|
end if;
|
|
end if;
|
|
|
|
-- Output a warning if the condition is known to be True
|
|
|
|
if Is_Entity_Name (Cond)
|
|
and then Entity (Cond) = Standard_True
|
|
then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(Ck_Node, "wrong length for array of}??",
|
|
CE_Length_Check_Failed,
|
|
Ent => Target_Typ,
|
|
Typ => Target_Typ);
|
|
|
|
-- If we were only doing a static check, or if checks are not
|
|
-- on, then we want to delete the check, since it is not needed.
|
|
-- We do this by replacing the if statement by a null statement
|
|
|
|
elsif Do_Static or else not Checks_On then
|
|
Remove_Warning_Messages (R_Cno);
|
|
Rewrite (R_Cno, Make_Null_Statement (Loc));
|
|
end if;
|
|
|
|
else
|
|
Install_Static_Check (R_Cno, Loc);
|
|
end if;
|
|
end loop;
|
|
end Apply_Selected_Length_Checks;
|
|
|
|
---------------------------------
|
|
-- Apply_Selected_Range_Checks --
|
|
---------------------------------
|
|
|
|
procedure Apply_Selected_Range_Checks
|
|
(Ck_Node : Node_Id;
|
|
Target_Typ : Entity_Id;
|
|
Source_Typ : Entity_Id;
|
|
Do_Static : Boolean)
|
|
is
|
|
Loc : constant Source_Ptr := Sloc (Ck_Node);
|
|
Checks_On : constant Boolean :=
|
|
not Index_Checks_Suppressed (Target_Typ)
|
|
or else
|
|
not Range_Checks_Suppressed (Target_Typ);
|
|
|
|
Cond : Node_Id;
|
|
R_Cno : Node_Id;
|
|
R_Result : Check_Result;
|
|
|
|
begin
|
|
if not Expander_Active or not Checks_On then
|
|
return;
|
|
end if;
|
|
|
|
R_Result :=
|
|
Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty);
|
|
|
|
for J in 1 .. 2 loop
|
|
R_Cno := R_Result (J);
|
|
exit when No (R_Cno);
|
|
|
|
-- The range check requires runtime evaluation. Depending on what its
|
|
-- triggering condition is, the check may be converted into a compile
|
|
-- time constraint check.
|
|
|
|
if Nkind (R_Cno) = N_Raise_Constraint_Error
|
|
and then Present (Condition (R_Cno))
|
|
then
|
|
Cond := Condition (R_Cno);
|
|
|
|
-- Insert the range check before the related context. Note that
|
|
-- this action analyses the triggering condition.
|
|
|
|
Insert_Action (Ck_Node, R_Cno);
|
|
|
|
-- This old code doesn't make sense, why is the context flagged as
|
|
-- requiring dynamic range checks now in the middle of generating
|
|
-- them ???
|
|
|
|
if not Do_Static then
|
|
Set_Has_Dynamic_Range_Check (Ck_Node);
|
|
end if;
|
|
|
|
-- The triggering condition evaluates to True, the range check
|
|
-- can be converted into a compile time constraint check.
|
|
|
|
if Is_Entity_Name (Cond)
|
|
and then Entity (Cond) = Standard_True
|
|
then
|
|
-- Since an N_Range is technically not an expression, we have
|
|
-- to set one of the bounds to C_E and then just flag the
|
|
-- N_Range. The warning message will point to the lower bound
|
|
-- and complain about a range, which seems OK.
|
|
|
|
if Nkind (Ck_Node) = N_Range then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(Low_Bound (Ck_Node),
|
|
"static range out of bounds of}??",
|
|
CE_Range_Check_Failed,
|
|
Ent => Target_Typ,
|
|
Typ => Target_Typ);
|
|
|
|
Set_Raises_Constraint_Error (Ck_Node);
|
|
|
|
else
|
|
Apply_Compile_Time_Constraint_Error
|
|
(Ck_Node,
|
|
"static value out of range of}??",
|
|
CE_Range_Check_Failed,
|
|
Ent => Target_Typ,
|
|
Typ => Target_Typ);
|
|
end if;
|
|
|
|
-- If we were only doing a static check, or if checks are not
|
|
-- on, then we want to delete the check, since it is not needed.
|
|
-- We do this by replacing the if statement by a null statement
|
|
|
|
elsif Do_Static then
|
|
Remove_Warning_Messages (R_Cno);
|
|
Rewrite (R_Cno, Make_Null_Statement (Loc));
|
|
end if;
|
|
|
|
-- The range check raises Constraint_Error explicitly
|
|
|
|
else
|
|
Install_Static_Check (R_Cno, Loc);
|
|
end if;
|
|
end loop;
|
|
end Apply_Selected_Range_Checks;
|
|
|
|
-------------------------------
|
|
-- Apply_Static_Length_Check --
|
|
-------------------------------
|
|
|
|
procedure Apply_Static_Length_Check
|
|
(Expr : Node_Id;
|
|
Target_Typ : Entity_Id;
|
|
Source_Typ : Entity_Id := Empty)
|
|
is
|
|
begin
|
|
Apply_Selected_Length_Checks
|
|
(Expr, Target_Typ, Source_Typ, Do_Static => True);
|
|
end Apply_Static_Length_Check;
|
|
|
|
-------------------------------------
|
|
-- Apply_Subscript_Validity_Checks --
|
|
-------------------------------------
|
|
|
|
procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is
|
|
Sub : Node_Id;
|
|
|
|
begin
|
|
pragma Assert (Nkind (Expr) = N_Indexed_Component);
|
|
|
|
-- Loop through subscripts
|
|
|
|
Sub := First (Expressions (Expr));
|
|
while Present (Sub) loop
|
|
|
|
-- Check one subscript. Note that we do not worry about enumeration
|
|
-- type with holes, since we will convert the value to a Pos value
|
|
-- for the subscript, and that convert will do the necessary validity
|
|
-- check.
|
|
|
|
Ensure_Valid (Sub, Holes_OK => True);
|
|
|
|
-- Move to next subscript
|
|
|
|
Sub := Next (Sub);
|
|
end loop;
|
|
end Apply_Subscript_Validity_Checks;
|
|
|
|
----------------------------------
|
|
-- Apply_Type_Conversion_Checks --
|
|
----------------------------------
|
|
|
|
procedure Apply_Type_Conversion_Checks (N : Node_Id) is
|
|
Target_Type : constant Entity_Id := Etype (N);
|
|
Target_Base : constant Entity_Id := Base_Type (Target_Type);
|
|
Expr : constant Node_Id := Expression (N);
|
|
|
|
Expr_Type : constant Entity_Id := Underlying_Type (Etype (Expr));
|
|
-- Note: if Etype (Expr) is a private type without discriminants, its
|
|
-- full view might have discriminants with defaults, so we need the
|
|
-- full view here to retrieve the constraints.
|
|
|
|
begin
|
|
if Inside_A_Generic then
|
|
return;
|
|
|
|
-- Skip these checks if serious errors detected, there are some nasty
|
|
-- situations of incomplete trees that blow things up.
|
|
|
|
elsif Serious_Errors_Detected > 0 then
|
|
return;
|
|
|
|
-- Never generate discriminant checks for Unchecked_Union types
|
|
|
|
elsif Present (Expr_Type)
|
|
and then Is_Unchecked_Union (Expr_Type)
|
|
then
|
|
return;
|
|
|
|
-- Scalar type conversions of the form Target_Type (Expr) require a
|
|
-- range check if we cannot be sure that Expr is in the base type of
|
|
-- Target_Typ and also that Expr is in the range of Target_Typ. These
|
|
-- are not quite the same condition from an implementation point of
|
|
-- view, but clearly the second includes the first.
|
|
|
|
elsif Is_Scalar_Type (Target_Type) then
|
|
declare
|
|
Conv_OK : constant Boolean := Conversion_OK (N);
|
|
-- If the Conversion_OK flag on the type conversion is set and no
|
|
-- floating-point type is involved in the type conversion then
|
|
-- fixed-point values must be read as integral values.
|
|
|
|
Float_To_Int : constant Boolean :=
|
|
Is_Floating_Point_Type (Expr_Type)
|
|
and then Is_Integer_Type (Target_Type);
|
|
|
|
begin
|
|
if not Overflow_Checks_Suppressed (Target_Base)
|
|
and then not Overflow_Checks_Suppressed (Target_Type)
|
|
and then not
|
|
In_Subrange_Of (Expr_Type, Target_Base, Fixed_Int => Conv_OK)
|
|
and then not Float_To_Int
|
|
then
|
|
Activate_Overflow_Check (N);
|
|
end if;
|
|
|
|
if not Range_Checks_Suppressed (Target_Type)
|
|
and then not Range_Checks_Suppressed (Expr_Type)
|
|
then
|
|
if Float_To_Int then
|
|
Apply_Float_Conversion_Check (Expr, Target_Type);
|
|
else
|
|
Apply_Scalar_Range_Check
|
|
(Expr, Target_Type, Fixed_Int => Conv_OK);
|
|
|
|
-- If the target type has predicates, we need to indicate
|
|
-- the need for a check, even if Determine_Range finds that
|
|
-- the value is within bounds. This may be the case e.g for
|
|
-- a division with a constant denominator.
|
|
|
|
if Has_Predicates (Target_Type) then
|
|
Enable_Range_Check (Expr);
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end;
|
|
|
|
elsif Comes_From_Source (N)
|
|
and then not Discriminant_Checks_Suppressed (Target_Type)
|
|
and then Is_Record_Type (Target_Type)
|
|
and then Is_Derived_Type (Target_Type)
|
|
and then not Is_Tagged_Type (Target_Type)
|
|
and then not Is_Constrained (Target_Type)
|
|
and then Present (Stored_Constraint (Target_Type))
|
|
then
|
|
-- An unconstrained derived type may have inherited discriminant.
|
|
-- Build an actual discriminant constraint list using the stored
|
|
-- constraint, to verify that the expression of the parent type
|
|
-- satisfies the constraints imposed by the (unconstrained) derived
|
|
-- type. This applies to value conversions, not to view conversions
|
|
-- of tagged types.
|
|
|
|
declare
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Cond : Node_Id;
|
|
Constraint : Elmt_Id;
|
|
Discr_Value : Node_Id;
|
|
Discr : Entity_Id;
|
|
|
|
New_Constraints : constant Elist_Id := New_Elmt_List;
|
|
Old_Constraints : constant Elist_Id :=
|
|
Discriminant_Constraint (Expr_Type);
|
|
|
|
begin
|
|
Constraint := First_Elmt (Stored_Constraint (Target_Type));
|
|
while Present (Constraint) loop
|
|
Discr_Value := Node (Constraint);
|
|
|
|
if Is_Entity_Name (Discr_Value)
|
|
and then Ekind (Entity (Discr_Value)) = E_Discriminant
|
|
then
|
|
Discr := Corresponding_Discriminant (Entity (Discr_Value));
|
|
|
|
if Present (Discr)
|
|
and then Scope (Discr) = Base_Type (Expr_Type)
|
|
then
|
|
-- Parent is constrained by new discriminant. Obtain
|
|
-- Value of original discriminant in expression. If the
|
|
-- new discriminant has been used to constrain more than
|
|
-- one of the stored discriminants, this will provide the
|
|
-- required consistency check.
|
|
|
|
Append_Elmt
|
|
(Make_Selected_Component (Loc,
|
|
Prefix =>
|
|
Duplicate_Subexpr_No_Checks
|
|
(Expr, Name_Req => True),
|
|
Selector_Name =>
|
|
Make_Identifier (Loc, Chars (Discr))),
|
|
New_Constraints);
|
|
|
|
else
|
|
-- Discriminant of more remote ancestor ???
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- Derived type definition has an explicit value for this
|
|
-- stored discriminant.
|
|
|
|
else
|
|
Append_Elmt
|
|
(Duplicate_Subexpr_No_Checks (Discr_Value),
|
|
New_Constraints);
|
|
end if;
|
|
|
|
Next_Elmt (Constraint);
|
|
end loop;
|
|
|
|
-- Use the unconstrained expression type to retrieve the
|
|
-- discriminants of the parent, and apply momentarily the
|
|
-- discriminant constraint synthesized above.
|
|
|
|
Set_Discriminant_Constraint (Expr_Type, New_Constraints);
|
|
Cond := Build_Discriminant_Checks (Expr, Expr_Type);
|
|
Set_Discriminant_Constraint (Expr_Type, Old_Constraints);
|
|
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition => Cond,
|
|
Reason => CE_Discriminant_Check_Failed));
|
|
end;
|
|
|
|
-- For arrays, checks are set now, but conversions are applied during
|
|
-- expansion, to take into accounts changes of representation. The
|
|
-- checks become range checks on the base type or length checks on the
|
|
-- subtype, depending on whether the target type is unconstrained or
|
|
-- constrained. Note that the range check is put on the expression of a
|
|
-- type conversion, while the length check is put on the type conversion
|
|
-- itself.
|
|
|
|
elsif Is_Array_Type (Target_Type) then
|
|
if Is_Constrained (Target_Type) then
|
|
Set_Do_Length_Check (N);
|
|
else
|
|
Set_Do_Range_Check (Expr);
|
|
end if;
|
|
end if;
|
|
end Apply_Type_Conversion_Checks;
|
|
|
|
----------------------------------------------
|
|
-- Apply_Universal_Integer_Attribute_Checks --
|
|
----------------------------------------------
|
|
|
|
procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Typ : constant Entity_Id := Etype (N);
|
|
|
|
begin
|
|
if Inside_A_Generic then
|
|
return;
|
|
|
|
-- Nothing to do if checks are suppressed
|
|
|
|
elsif Range_Checks_Suppressed (Typ)
|
|
and then Overflow_Checks_Suppressed (Typ)
|
|
then
|
|
return;
|
|
|
|
-- Nothing to do if the attribute does not come from source. The
|
|
-- internal attributes we generate of this type do not need checks,
|
|
-- and furthermore the attempt to check them causes some circular
|
|
-- elaboration orders when dealing with packed types.
|
|
|
|
elsif not Comes_From_Source (N) then
|
|
return;
|
|
|
|
-- If the prefix is a selected component that depends on a discriminant
|
|
-- the check may improperly expose a discriminant instead of using
|
|
-- the bounds of the object itself. Set the type of the attribute to
|
|
-- the base type of the context, so that a check will be imposed when
|
|
-- needed (e.g. if the node appears as an index).
|
|
|
|
elsif Nkind (Prefix (N)) = N_Selected_Component
|
|
and then Ekind (Typ) = E_Signed_Integer_Subtype
|
|
and then Depends_On_Discriminant (Scalar_Range (Typ))
|
|
then
|
|
Set_Etype (N, Base_Type (Typ));
|
|
|
|
-- Otherwise, replace the attribute node with a type conversion node
|
|
-- whose expression is the attribute, retyped to universal integer, and
|
|
-- whose subtype mark is the target type. The call to analyze this
|
|
-- conversion will set range and overflow checks as required for proper
|
|
-- detection of an out of range value.
|
|
|
|
else
|
|
Set_Etype (N, Universal_Integer);
|
|
Set_Analyzed (N, True);
|
|
|
|
Rewrite (N,
|
|
Make_Type_Conversion (Loc,
|
|
Subtype_Mark => New_Occurrence_Of (Typ, Loc),
|
|
Expression => Relocate_Node (N)));
|
|
|
|
Analyze_And_Resolve (N, Typ);
|
|
return;
|
|
end if;
|
|
end Apply_Universal_Integer_Attribute_Checks;
|
|
|
|
-------------------------------------
|
|
-- Atomic_Synchronization_Disabled --
|
|
-------------------------------------
|
|
|
|
-- Note: internally Disable/Enable_Atomic_Synchronization is implemented
|
|
-- using a bogus check called Atomic_Synchronization. This is to make it
|
|
-- more convenient to get exactly the same semantics as [Un]Suppress.
|
|
|
|
function Atomic_Synchronization_Disabled (E : Entity_Id) return Boolean is
|
|
begin
|
|
-- If debug flag d.e is set, always return False, i.e. all atomic sync
|
|
-- looks enabled, since it is never disabled.
|
|
|
|
if Debug_Flag_Dot_E then
|
|
return False;
|
|
|
|
-- If debug flag d.d is set then always return True, i.e. all atomic
|
|
-- sync looks disabled, since it always tests True.
|
|
|
|
elsif Debug_Flag_Dot_D then
|
|
return True;
|
|
|
|
-- If entity present, then check result for that entity
|
|
|
|
elsif Present (E) and then Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Atomic_Synchronization);
|
|
|
|
-- Otherwise result depends on current scope setting
|
|
|
|
else
|
|
return Scope_Suppress.Suppress (Atomic_Synchronization);
|
|
end if;
|
|
end Atomic_Synchronization_Disabled;
|
|
|
|
-------------------------------
|
|
-- Build_Discriminant_Checks --
|
|
-------------------------------
|
|
|
|
function Build_Discriminant_Checks
|
|
(N : Node_Id;
|
|
T_Typ : Entity_Id) return Node_Id
|
|
is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Cond : Node_Id;
|
|
Disc : Elmt_Id;
|
|
Disc_Ent : Entity_Id;
|
|
Dref : Node_Id;
|
|
Dval : Node_Id;
|
|
|
|
function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id;
|
|
|
|
----------------------------------
|
|
-- Aggregate_Discriminant_Value --
|
|
----------------------------------
|
|
|
|
function Aggregate_Discriminant_Val (Disc : Entity_Id) return Node_Id is
|
|
Assoc : Node_Id;
|
|
|
|
begin
|
|
-- The aggregate has been normalized with named associations. We use
|
|
-- the Chars field to locate the discriminant to take into account
|
|
-- discriminants in derived types, which carry the same name as those
|
|
-- in the parent.
|
|
|
|
Assoc := First (Component_Associations (N));
|
|
while Present (Assoc) loop
|
|
if Chars (First (Choices (Assoc))) = Chars (Disc) then
|
|
return Expression (Assoc);
|
|
else
|
|
Next (Assoc);
|
|
end if;
|
|
end loop;
|
|
|
|
-- Discriminant must have been found in the loop above
|
|
|
|
raise Program_Error;
|
|
end Aggregate_Discriminant_Val;
|
|
|
|
-- Start of processing for Build_Discriminant_Checks
|
|
|
|
begin
|
|
-- Loop through discriminants evolving the condition
|
|
|
|
Cond := Empty;
|
|
Disc := First_Elmt (Discriminant_Constraint (T_Typ));
|
|
|
|
-- For a fully private type, use the discriminants of the parent type
|
|
|
|
if Is_Private_Type (T_Typ)
|
|
and then No (Full_View (T_Typ))
|
|
then
|
|
Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ)));
|
|
else
|
|
Disc_Ent := First_Discriminant (T_Typ);
|
|
end if;
|
|
|
|
while Present (Disc) loop
|
|
Dval := Node (Disc);
|
|
|
|
if Nkind (Dval) = N_Identifier
|
|
and then Ekind (Entity (Dval)) = E_Discriminant
|
|
then
|
|
Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc);
|
|
else
|
|
Dval := Duplicate_Subexpr_No_Checks (Dval);
|
|
end if;
|
|
|
|
-- If we have an Unchecked_Union node, we can infer the discriminants
|
|
-- of the node.
|
|
|
|
if Is_Unchecked_Union (Base_Type (T_Typ)) then
|
|
Dref := New_Copy (
|
|
Get_Discriminant_Value (
|
|
First_Discriminant (T_Typ),
|
|
T_Typ,
|
|
Stored_Constraint (T_Typ)));
|
|
|
|
elsif Nkind (N) = N_Aggregate then
|
|
Dref :=
|
|
Duplicate_Subexpr_No_Checks
|
|
(Aggregate_Discriminant_Val (Disc_Ent));
|
|
|
|
else
|
|
Dref :=
|
|
Make_Selected_Component (Loc,
|
|
Prefix =>
|
|
Duplicate_Subexpr_No_Checks (N, Name_Req => True),
|
|
Selector_Name => Make_Identifier (Loc, Chars (Disc_Ent)));
|
|
|
|
Set_Is_In_Discriminant_Check (Dref);
|
|
end if;
|
|
|
|
Evolve_Or_Else (Cond,
|
|
Make_Op_Ne (Loc,
|
|
Left_Opnd => Dref,
|
|
Right_Opnd => Dval));
|
|
|
|
Next_Elmt (Disc);
|
|
Next_Discriminant (Disc_Ent);
|
|
end loop;
|
|
|
|
return Cond;
|
|
end Build_Discriminant_Checks;
|
|
|
|
------------------
|
|
-- Check_Needed --
|
|
------------------
|
|
|
|
function Check_Needed (Nod : Node_Id; Check : Check_Type) return Boolean is
|
|
N : Node_Id;
|
|
P : Node_Id;
|
|
K : Node_Kind;
|
|
L : Node_Id;
|
|
R : Node_Id;
|
|
|
|
function Left_Expression (Op : Node_Id) return Node_Id;
|
|
-- Return the relevant expression from the left operand of the given
|
|
-- short circuit form: this is LO itself, except if LO is a qualified
|
|
-- expression, a type conversion, or an expression with actions, in
|
|
-- which case this is Left_Expression (Expression (LO)).
|
|
|
|
---------------------
|
|
-- Left_Expression --
|
|
---------------------
|
|
|
|
function Left_Expression (Op : Node_Id) return Node_Id is
|
|
LE : Node_Id := Left_Opnd (Op);
|
|
begin
|
|
while Nkind_In (LE, N_Qualified_Expression,
|
|
N_Type_Conversion,
|
|
N_Expression_With_Actions)
|
|
loop
|
|
LE := Expression (LE);
|
|
end loop;
|
|
|
|
return LE;
|
|
end Left_Expression;
|
|
|
|
-- Start of processing for Check_Needed
|
|
|
|
begin
|
|
-- Always check if not simple entity
|
|
|
|
if Nkind (Nod) not in N_Has_Entity
|
|
or else not Comes_From_Source (Nod)
|
|
then
|
|
return True;
|
|
end if;
|
|
|
|
-- Look up tree for short circuit
|
|
|
|
N := Nod;
|
|
loop
|
|
P := Parent (N);
|
|
K := Nkind (P);
|
|
|
|
-- Done if out of subexpression (note that we allow generated stuff
|
|
-- such as itype declarations in this context, to keep the loop going
|
|
-- since we may well have generated such stuff in complex situations.
|
|
-- Also done if no parent (probably an error condition, but no point
|
|
-- in behaving nasty if we find it).
|
|
|
|
if No (P)
|
|
or else (K not in N_Subexpr and then Comes_From_Source (P))
|
|
then
|
|
return True;
|
|
|
|
-- Or/Or Else case, where test is part of the right operand, or is
|
|
-- part of one of the actions associated with the right operand, and
|
|
-- the left operand is an equality test.
|
|
|
|
elsif K = N_Op_Or then
|
|
exit when N = Right_Opnd (P)
|
|
and then Nkind (Left_Expression (P)) = N_Op_Eq;
|
|
|
|
elsif K = N_Or_Else then
|
|
exit when (N = Right_Opnd (P)
|
|
or else
|
|
(Is_List_Member (N)
|
|
and then List_Containing (N) = Actions (P)))
|
|
and then Nkind (Left_Expression (P)) = N_Op_Eq;
|
|
|
|
-- Similar test for the And/And then case, where the left operand
|
|
-- is an inequality test.
|
|
|
|
elsif K = N_Op_And then
|
|
exit when N = Right_Opnd (P)
|
|
and then Nkind (Left_Expression (P)) = N_Op_Ne;
|
|
|
|
elsif K = N_And_Then then
|
|
exit when (N = Right_Opnd (P)
|
|
or else
|
|
(Is_List_Member (N)
|
|
and then List_Containing (N) = Actions (P)))
|
|
and then Nkind (Left_Expression (P)) = N_Op_Ne;
|
|
end if;
|
|
|
|
N := P;
|
|
end loop;
|
|
|
|
-- If we fall through the loop, then we have a conditional with an
|
|
-- appropriate test as its left operand, so look further.
|
|
|
|
L := Left_Expression (P);
|
|
|
|
-- L is an "=" or "/=" operator: extract its operands
|
|
|
|
R := Right_Opnd (L);
|
|
L := Left_Opnd (L);
|
|
|
|
-- Left operand of test must match original variable
|
|
|
|
if Nkind (L) not in N_Has_Entity or else Entity (L) /= Entity (Nod) then
|
|
return True;
|
|
end if;
|
|
|
|
-- Right operand of test must be key value (zero or null)
|
|
|
|
case Check is
|
|
when Access_Check =>
|
|
if not Known_Null (R) then
|
|
return True;
|
|
end if;
|
|
|
|
when Division_Check =>
|
|
if not Compile_Time_Known_Value (R)
|
|
or else Expr_Value (R) /= Uint_0
|
|
then
|
|
return True;
|
|
end if;
|
|
|
|
when others =>
|
|
raise Program_Error;
|
|
end case;
|
|
|
|
-- Here we have the optimizable case, warn if not short-circuited
|
|
|
|
if K = N_Op_And or else K = N_Op_Or then
|
|
Error_Msg_Warn := SPARK_Mode /= On;
|
|
|
|
case Check is
|
|
when Access_Check =>
|
|
if GNATprove_Mode then
|
|
Error_Msg_N
|
|
("Constraint_Error might have been raised (access check)",
|
|
Parent (Nod));
|
|
else
|
|
Error_Msg_N
|
|
("Constraint_Error may be raised (access check)??",
|
|
Parent (Nod));
|
|
end if;
|
|
|
|
when Division_Check =>
|
|
if GNATprove_Mode then
|
|
Error_Msg_N
|
|
("Constraint_Error might have been raised (zero divide)",
|
|
Parent (Nod));
|
|
else
|
|
Error_Msg_N
|
|
("Constraint_Error may be raised (zero divide)??",
|
|
Parent (Nod));
|
|
end if;
|
|
|
|
when others =>
|
|
raise Program_Error;
|
|
end case;
|
|
|
|
if K = N_Op_And then
|
|
Error_Msg_N -- CODEFIX
|
|
("use `AND THEN` instead of AND??", P);
|
|
else
|
|
Error_Msg_N -- CODEFIX
|
|
("use `OR ELSE` instead of OR??", P);
|
|
end if;
|
|
|
|
-- If not short-circuited, we need the check
|
|
|
|
return True;
|
|
|
|
-- If short-circuited, we can omit the check
|
|
|
|
else
|
|
return False;
|
|
end if;
|
|
end Check_Needed;
|
|
|
|
-----------------------------------
|
|
-- Check_Valid_Lvalue_Subscripts --
|
|
-----------------------------------
|
|
|
|
procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is
|
|
begin
|
|
-- Skip this if range checks are suppressed
|
|
|
|
if Range_Checks_Suppressed (Etype (Expr)) then
|
|
return;
|
|
|
|
-- Only do this check for expressions that come from source. We assume
|
|
-- that expander generated assignments explicitly include any necessary
|
|
-- checks. Note that this is not just an optimization, it avoids
|
|
-- infinite recursions.
|
|
|
|
elsif not Comes_From_Source (Expr) then
|
|
return;
|
|
|
|
-- For a selected component, check the prefix
|
|
|
|
elsif Nkind (Expr) = N_Selected_Component then
|
|
Check_Valid_Lvalue_Subscripts (Prefix (Expr));
|
|
return;
|
|
|
|
-- Case of indexed component
|
|
|
|
elsif Nkind (Expr) = N_Indexed_Component then
|
|
Apply_Subscript_Validity_Checks (Expr);
|
|
|
|
-- Prefix may itself be or contain an indexed component, and these
|
|
-- subscripts need checking as well.
|
|
|
|
Check_Valid_Lvalue_Subscripts (Prefix (Expr));
|
|
end if;
|
|
end Check_Valid_Lvalue_Subscripts;
|
|
|
|
----------------------------------
|
|
-- Null_Exclusion_Static_Checks --
|
|
----------------------------------
|
|
|
|
procedure Null_Exclusion_Static_Checks (N : Node_Id) is
|
|
Error_Node : Node_Id;
|
|
Expr : Node_Id;
|
|
Has_Null : constant Boolean := Has_Null_Exclusion (N);
|
|
K : constant Node_Kind := Nkind (N);
|
|
Typ : Entity_Id;
|
|
|
|
begin
|
|
pragma Assert
|
|
(Nkind_In (K, N_Component_Declaration,
|
|
N_Discriminant_Specification,
|
|
N_Function_Specification,
|
|
N_Object_Declaration,
|
|
N_Parameter_Specification));
|
|
|
|
if K = N_Function_Specification then
|
|
Typ := Etype (Defining_Entity (N));
|
|
else
|
|
Typ := Etype (Defining_Identifier (N));
|
|
end if;
|
|
|
|
case K is
|
|
when N_Component_Declaration =>
|
|
if Present (Access_Definition (Component_Definition (N))) then
|
|
Error_Node := Component_Definition (N);
|
|
else
|
|
Error_Node := Subtype_Indication (Component_Definition (N));
|
|
end if;
|
|
|
|
when N_Discriminant_Specification =>
|
|
Error_Node := Discriminant_Type (N);
|
|
|
|
when N_Function_Specification =>
|
|
Error_Node := Result_Definition (N);
|
|
|
|
when N_Object_Declaration =>
|
|
Error_Node := Object_Definition (N);
|
|
|
|
when N_Parameter_Specification =>
|
|
Error_Node := Parameter_Type (N);
|
|
|
|
when others =>
|
|
raise Program_Error;
|
|
end case;
|
|
|
|
if Has_Null then
|
|
|
|
-- Enforce legality rule 3.10 (13): A null exclusion can only be
|
|
-- applied to an access [sub]type.
|
|
|
|
if not Is_Access_Type (Typ) then
|
|
Error_Msg_N
|
|
("`NOT NULL` allowed only for an access type", Error_Node);
|
|
|
|
-- Enforce legality rule RM 3.10(14/1): A null exclusion can only
|
|
-- be applied to a [sub]type that does not exclude null already.
|
|
|
|
elsif Can_Never_Be_Null (Typ)
|
|
and then Comes_From_Source (Typ)
|
|
then
|
|
Error_Msg_NE
|
|
("`NOT NULL` not allowed (& already excludes null)",
|
|
Error_Node, Typ);
|
|
end if;
|
|
end if;
|
|
|
|
-- Check that null-excluding objects are always initialized, except for
|
|
-- deferred constants, for which the expression will appear in the full
|
|
-- declaration.
|
|
|
|
if K = N_Object_Declaration
|
|
and then No (Expression (N))
|
|
and then not Constant_Present (N)
|
|
and then not No_Initialization (N)
|
|
then
|
|
-- Add an expression that assigns null. This node is needed by
|
|
-- Apply_Compile_Time_Constraint_Error, which will replace this with
|
|
-- a Constraint_Error node.
|
|
|
|
Set_Expression (N, Make_Null (Sloc (N)));
|
|
Set_Etype (Expression (N), Etype (Defining_Identifier (N)));
|
|
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N => Expression (N),
|
|
Msg =>
|
|
"(Ada 2005) null-excluding objects must be initialized??",
|
|
Reason => CE_Null_Not_Allowed);
|
|
end if;
|
|
|
|
-- Check that a null-excluding component, formal or object is not being
|
|
-- assigned a null value. Otherwise generate a warning message and
|
|
-- replace Expression (N) by an N_Constraint_Error node.
|
|
|
|
if K /= N_Function_Specification then
|
|
Expr := Expression (N);
|
|
|
|
if Present (Expr) and then Known_Null (Expr) then
|
|
case K is
|
|
when N_Component_Declaration |
|
|
N_Discriminant_Specification =>
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N => Expr,
|
|
Msg => "(Ada 2005) null not allowed "
|
|
& "in null-excluding components??",
|
|
Reason => CE_Null_Not_Allowed);
|
|
|
|
when N_Object_Declaration =>
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N => Expr,
|
|
Msg => "(Ada 2005) null not allowed "
|
|
& "in null-excluding objects??",
|
|
Reason => CE_Null_Not_Allowed);
|
|
|
|
when N_Parameter_Specification =>
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N => Expr,
|
|
Msg => "(Ada 2005) null not allowed "
|
|
& "in null-excluding formals??",
|
|
Reason => CE_Null_Not_Allowed);
|
|
|
|
when others =>
|
|
null;
|
|
end case;
|
|
end if;
|
|
end if;
|
|
end Null_Exclusion_Static_Checks;
|
|
|
|
----------------------------------
|
|
-- Conditional_Statements_Begin --
|
|
----------------------------------
|
|
|
|
procedure Conditional_Statements_Begin is
|
|
begin
|
|
Saved_Checks_TOS := Saved_Checks_TOS + 1;
|
|
|
|
-- If stack overflows, kill all checks, that way we know to simply reset
|
|
-- the number of saved checks to zero on return. This should never occur
|
|
-- in practice.
|
|
|
|
if Saved_Checks_TOS > Saved_Checks_Stack'Last then
|
|
Kill_All_Checks;
|
|
|
|
-- In the normal case, we just make a new stack entry saving the current
|
|
-- number of saved checks for a later restore.
|
|
|
|
else
|
|
Saved_Checks_Stack (Saved_Checks_TOS) := Num_Saved_Checks;
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Conditional_Statements_Begin: Num_Saved_Checks = ",
|
|
Num_Saved_Checks);
|
|
end if;
|
|
end if;
|
|
end Conditional_Statements_Begin;
|
|
|
|
--------------------------------
|
|
-- Conditional_Statements_End --
|
|
--------------------------------
|
|
|
|
procedure Conditional_Statements_End is
|
|
begin
|
|
pragma Assert (Saved_Checks_TOS > 0);
|
|
|
|
-- If the saved checks stack overflowed, then we killed all checks, so
|
|
-- setting the number of saved checks back to zero is correct. This
|
|
-- should never occur in practice.
|
|
|
|
if Saved_Checks_TOS > Saved_Checks_Stack'Last then
|
|
Num_Saved_Checks := 0;
|
|
|
|
-- In the normal case, restore the number of saved checks from the top
|
|
-- stack entry.
|
|
|
|
else
|
|
Num_Saved_Checks := Saved_Checks_Stack (Saved_Checks_TOS);
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Conditional_Statements_End: Num_Saved_Checks = ",
|
|
Num_Saved_Checks);
|
|
end if;
|
|
end if;
|
|
|
|
Saved_Checks_TOS := Saved_Checks_TOS - 1;
|
|
end Conditional_Statements_End;
|
|
|
|
-------------------------
|
|
-- Convert_From_Bignum --
|
|
-------------------------
|
|
|
|
function Convert_From_Bignum (N : Node_Id) return Node_Id is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
|
|
begin
|
|
pragma Assert (Is_RTE (Etype (N), RE_Bignum));
|
|
|
|
-- Construct call From Bignum
|
|
|
|
return
|
|
Make_Function_Call (Loc,
|
|
Name =>
|
|
New_Occurrence_Of (RTE (RE_From_Bignum), Loc),
|
|
Parameter_Associations => New_List (Relocate_Node (N)));
|
|
end Convert_From_Bignum;
|
|
|
|
-----------------------
|
|
-- Convert_To_Bignum --
|
|
-----------------------
|
|
|
|
function Convert_To_Bignum (N : Node_Id) return Node_Id is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
|
|
begin
|
|
-- Nothing to do if Bignum already except call Relocate_Node
|
|
|
|
if Is_RTE (Etype (N), RE_Bignum) then
|
|
return Relocate_Node (N);
|
|
|
|
-- Otherwise construct call to To_Bignum, converting the operand to the
|
|
-- required Long_Long_Integer form.
|
|
|
|
else
|
|
pragma Assert (Is_Signed_Integer_Type (Etype (N)));
|
|
return
|
|
Make_Function_Call (Loc,
|
|
Name =>
|
|
New_Occurrence_Of (RTE (RE_To_Bignum), Loc),
|
|
Parameter_Associations => New_List (
|
|
Convert_To (Standard_Long_Long_Integer, Relocate_Node (N))));
|
|
end if;
|
|
end Convert_To_Bignum;
|
|
|
|
---------------------
|
|
-- Determine_Range --
|
|
---------------------
|
|
|
|
Cache_Size : constant := 2 ** 10;
|
|
type Cache_Index is range 0 .. Cache_Size - 1;
|
|
-- Determine size of below cache (power of 2 is more efficient)
|
|
|
|
Determine_Range_Cache_N : array (Cache_Index) of Node_Id;
|
|
Determine_Range_Cache_V : array (Cache_Index) of Boolean;
|
|
Determine_Range_Cache_Lo : array (Cache_Index) of Uint;
|
|
Determine_Range_Cache_Hi : array (Cache_Index) of Uint;
|
|
Determine_Range_Cache_Lo_R : array (Cache_Index) of Ureal;
|
|
Determine_Range_Cache_Hi_R : array (Cache_Index) of Ureal;
|
|
-- The above arrays are used to implement a small direct cache for
|
|
-- Determine_Range and Determine_Range_R calls. Because of the way these
|
|
-- subprograms recursively traces subexpressions, and because overflow
|
|
-- checking calls the routine on the way up the tree, a quadratic behavior
|
|
-- can otherwise be encountered in large expressions. The cache entry for
|
|
-- node N is stored in the (N mod Cache_Size) entry, and can be validated
|
|
-- by checking the actual node value stored there. The Range_Cache_V array
|
|
-- records the setting of Assume_Valid for the cache entry.
|
|
|
|
procedure Determine_Range
|
|
(N : Node_Id;
|
|
OK : out Boolean;
|
|
Lo : out Uint;
|
|
Hi : out Uint;
|
|
Assume_Valid : Boolean := False)
|
|
is
|
|
Typ : Entity_Id := Etype (N);
|
|
-- Type to use, may get reset to base type for possibly invalid entity
|
|
|
|
Lo_Left : Uint;
|
|
Hi_Left : Uint;
|
|
-- Lo and Hi bounds of left operand
|
|
|
|
Lo_Right : Uint;
|
|
Hi_Right : Uint;
|
|
-- Lo and Hi bounds of right (or only) operand
|
|
|
|
Bound : Node_Id;
|
|
-- Temp variable used to hold a bound node
|
|
|
|
Hbound : Uint;
|
|
-- High bound of base type of expression
|
|
|
|
Lor : Uint;
|
|
Hir : Uint;
|
|
-- Refined values for low and high bounds, after tightening
|
|
|
|
OK1 : Boolean;
|
|
-- Used in lower level calls to indicate if call succeeded
|
|
|
|
Cindex : Cache_Index;
|
|
-- Used to search cache
|
|
|
|
Btyp : Entity_Id;
|
|
-- Base type
|
|
|
|
function OK_Operands return Boolean;
|
|
-- Used for binary operators. Determines the ranges of the left and
|
|
-- right operands, and if they are both OK, returns True, and puts
|
|
-- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
|
|
|
|
-----------------
|
|
-- OK_Operands --
|
|
-----------------
|
|
|
|
function OK_Operands return Boolean is
|
|
begin
|
|
Determine_Range
|
|
(Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid);
|
|
|
|
if not OK1 then
|
|
return False;
|
|
end if;
|
|
|
|
Determine_Range
|
|
(Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid);
|
|
return OK1;
|
|
end OK_Operands;
|
|
|
|
-- Start of processing for Determine_Range
|
|
|
|
begin
|
|
-- Prevent junk warnings by initializing range variables
|
|
|
|
Lo := No_Uint;
|
|
Hi := No_Uint;
|
|
Lor := No_Uint;
|
|
Hir := No_Uint;
|
|
|
|
-- For temporary constants internally generated to remove side effects
|
|
-- we must use the corresponding expression to determine the range of
|
|
-- the expression. But note that the expander can also generate
|
|
-- constants in other cases, including deferred constants.
|
|
|
|
if Is_Entity_Name (N)
|
|
and then Nkind (Parent (Entity (N))) = N_Object_Declaration
|
|
and then Ekind (Entity (N)) = E_Constant
|
|
and then Is_Internal_Name (Chars (Entity (N)))
|
|
then
|
|
if Present (Expression (Parent (Entity (N)))) then
|
|
Determine_Range
|
|
(Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid);
|
|
|
|
elsif Present (Full_View (Entity (N))) then
|
|
Determine_Range
|
|
(Expression (Parent (Full_View (Entity (N)))),
|
|
OK, Lo, Hi, Assume_Valid);
|
|
|
|
else
|
|
OK := False;
|
|
end if;
|
|
return;
|
|
end if;
|
|
|
|
-- If type is not defined, we can't determine its range
|
|
|
|
if No (Typ)
|
|
|
|
-- We don't deal with anything except discrete types
|
|
|
|
or else not Is_Discrete_Type (Typ)
|
|
|
|
-- Ignore type for which an error has been posted, since range in
|
|
-- this case may well be a bogosity deriving from the error. Also
|
|
-- ignore if error posted on the reference node.
|
|
|
|
or else Error_Posted (N) or else Error_Posted (Typ)
|
|
then
|
|
OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- For all other cases, we can determine the range
|
|
|
|
OK := True;
|
|
|
|
-- If value is compile time known, then the possible range is the one
|
|
-- value that we know this expression definitely has.
|
|
|
|
if Compile_Time_Known_Value (N) then
|
|
Lo := Expr_Value (N);
|
|
Hi := Lo;
|
|
return;
|
|
end if;
|
|
|
|
-- Return if already in the cache
|
|
|
|
Cindex := Cache_Index (N mod Cache_Size);
|
|
|
|
if Determine_Range_Cache_N (Cindex) = N
|
|
and then
|
|
Determine_Range_Cache_V (Cindex) = Assume_Valid
|
|
then
|
|
Lo := Determine_Range_Cache_Lo (Cindex);
|
|
Hi := Determine_Range_Cache_Hi (Cindex);
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise, start by finding the bounds of the type of the expression,
|
|
-- the value cannot be outside this range (if it is, then we have an
|
|
-- overflow situation, which is a separate check, we are talking here
|
|
-- only about the expression value).
|
|
|
|
-- First a check, never try to find the bounds of a generic type, since
|
|
-- these bounds are always junk values, and it is only valid to look at
|
|
-- the bounds in an instance.
|
|
|
|
if Is_Generic_Type (Typ) then
|
|
OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- First step, change to use base type unless we know the value is valid
|
|
|
|
if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N)))
|
|
or else Assume_No_Invalid_Values
|
|
or else Assume_Valid
|
|
then
|
|
null;
|
|
else
|
|
Typ := Underlying_Type (Base_Type (Typ));
|
|
end if;
|
|
|
|
-- Retrieve the base type. Handle the case where the base type is a
|
|
-- private enumeration type.
|
|
|
|
Btyp := Base_Type (Typ);
|
|
|
|
if Is_Private_Type (Btyp) and then Present (Full_View (Btyp)) then
|
|
Btyp := Full_View (Btyp);
|
|
end if;
|
|
|
|
-- We use the actual bound unless it is dynamic, in which case use the
|
|
-- corresponding base type bound if possible. If we can't get a bound
|
|
-- then we figure we can't determine the range (a peculiar case, that
|
|
-- perhaps cannot happen, but there is no point in bombing in this
|
|
-- optimization circuit.
|
|
|
|
-- First the low bound
|
|
|
|
Bound := Type_Low_Bound (Typ);
|
|
|
|
if Compile_Time_Known_Value (Bound) then
|
|
Lo := Expr_Value (Bound);
|
|
|
|
elsif Compile_Time_Known_Value (Type_Low_Bound (Btyp)) then
|
|
Lo := Expr_Value (Type_Low_Bound (Btyp));
|
|
|
|
else
|
|
OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- Now the high bound
|
|
|
|
Bound := Type_High_Bound (Typ);
|
|
|
|
-- We need the high bound of the base type later on, and this should
|
|
-- always be compile time known. Again, it is not clear that this
|
|
-- can ever be false, but no point in bombing.
|
|
|
|
if Compile_Time_Known_Value (Type_High_Bound (Btyp)) then
|
|
Hbound := Expr_Value (Type_High_Bound (Btyp));
|
|
Hi := Hbound;
|
|
|
|
else
|
|
OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- If we have a static subtype, then that may have a tighter bound so
|
|
-- use the upper bound of the subtype instead in this case.
|
|
|
|
if Compile_Time_Known_Value (Bound) then
|
|
Hi := Expr_Value (Bound);
|
|
end if;
|
|
|
|
-- We may be able to refine this value in certain situations. If any
|
|
-- refinement is possible, then Lor and Hir are set to possibly tighter
|
|
-- bounds, and OK1 is set to True.
|
|
|
|
case Nkind (N) is
|
|
|
|
-- For unary plus, result is limited by range of operand
|
|
|
|
when N_Op_Plus =>
|
|
Determine_Range
|
|
(Right_Opnd (N), OK1, Lor, Hir, Assume_Valid);
|
|
|
|
-- For unary minus, determine range of operand, and negate it
|
|
|
|
when N_Op_Minus =>
|
|
Determine_Range
|
|
(Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid);
|
|
|
|
if OK1 then
|
|
Lor := -Hi_Right;
|
|
Hir := -Lo_Right;
|
|
end if;
|
|
|
|
-- For binary addition, get range of each operand and do the
|
|
-- addition to get the result range.
|
|
|
|
when N_Op_Add =>
|
|
if OK_Operands then
|
|
Lor := Lo_Left + Lo_Right;
|
|
Hir := Hi_Left + Hi_Right;
|
|
end if;
|
|
|
|
-- Division is tricky. The only case we consider is where the right
|
|
-- operand is a positive constant, and in this case we simply divide
|
|
-- the bounds of the left operand
|
|
|
|
when N_Op_Divide =>
|
|
if OK_Operands then
|
|
if Lo_Right = Hi_Right
|
|
and then Lo_Right > 0
|
|
then
|
|
Lor := Lo_Left / Lo_Right;
|
|
Hir := Hi_Left / Lo_Right;
|
|
else
|
|
OK1 := False;
|
|
end if;
|
|
end if;
|
|
|
|
-- For binary subtraction, get range of each operand and do the worst
|
|
-- case subtraction to get the result range.
|
|
|
|
when N_Op_Subtract =>
|
|
if OK_Operands then
|
|
Lor := Lo_Left - Hi_Right;
|
|
Hir := Hi_Left - Lo_Right;
|
|
end if;
|
|
|
|
-- For MOD, if right operand is a positive constant, then result must
|
|
-- be in the allowable range of mod results.
|
|
|
|
when N_Op_Mod =>
|
|
if OK_Operands then
|
|
if Lo_Right = Hi_Right
|
|
and then Lo_Right /= 0
|
|
then
|
|
if Lo_Right > 0 then
|
|
Lor := Uint_0;
|
|
Hir := Lo_Right - 1;
|
|
|
|
else -- Lo_Right < 0
|
|
Lor := Lo_Right + 1;
|
|
Hir := Uint_0;
|
|
end if;
|
|
|
|
else
|
|
OK1 := False;
|
|
end if;
|
|
end if;
|
|
|
|
-- For REM, if right operand is a positive constant, then result must
|
|
-- be in the allowable range of mod results.
|
|
|
|
when N_Op_Rem =>
|
|
if OK_Operands then
|
|
if Lo_Right = Hi_Right
|
|
and then Lo_Right /= 0
|
|
then
|
|
declare
|
|
Dval : constant Uint := (abs Lo_Right) - 1;
|
|
|
|
begin
|
|
-- The sign of the result depends on the sign of the
|
|
-- dividend (but not on the sign of the divisor, hence
|
|
-- the abs operation above).
|
|
|
|
if Lo_Left < 0 then
|
|
Lor := -Dval;
|
|
else
|
|
Lor := Uint_0;
|
|
end if;
|
|
|
|
if Hi_Left < 0 then
|
|
Hir := Uint_0;
|
|
else
|
|
Hir := Dval;
|
|
end if;
|
|
end;
|
|
|
|
else
|
|
OK1 := False;
|
|
end if;
|
|
end if;
|
|
|
|
-- Attribute reference cases
|
|
|
|
when N_Attribute_Reference =>
|
|
case Attribute_Name (N) is
|
|
|
|
-- For Pos/Val attributes, we can refine the range using the
|
|
-- possible range of values of the attribute expression.
|
|
|
|
when Name_Pos | Name_Val =>
|
|
Determine_Range
|
|
(First (Expressions (N)), OK1, Lor, Hir, Assume_Valid);
|
|
|
|
-- For Length attribute, use the bounds of the corresponding
|
|
-- index type to refine the range.
|
|
|
|
when Name_Length =>
|
|
declare
|
|
Atyp : Entity_Id := Etype (Prefix (N));
|
|
Inum : Nat;
|
|
Indx : Node_Id;
|
|
|
|
LL, LU : Uint;
|
|
UL, UU : Uint;
|
|
|
|
begin
|
|
if Is_Access_Type (Atyp) then
|
|
Atyp := Designated_Type (Atyp);
|
|
end if;
|
|
|
|
-- For string literal, we know exact value
|
|
|
|
if Ekind (Atyp) = E_String_Literal_Subtype then
|
|
OK := True;
|
|
Lo := String_Literal_Length (Atyp);
|
|
Hi := String_Literal_Length (Atyp);
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise check for expression given
|
|
|
|
if No (Expressions (N)) then
|
|
Inum := 1;
|
|
else
|
|
Inum :=
|
|
UI_To_Int (Expr_Value (First (Expressions (N))));
|
|
end if;
|
|
|
|
Indx := First_Index (Atyp);
|
|
for J in 2 .. Inum loop
|
|
Indx := Next_Index (Indx);
|
|
end loop;
|
|
|
|
-- If the index type is a formal type or derived from
|
|
-- one, the bounds are not static.
|
|
|
|
if Is_Generic_Type (Root_Type (Etype (Indx))) then
|
|
OK := False;
|
|
return;
|
|
end if;
|
|
|
|
Determine_Range
|
|
(Type_Low_Bound (Etype (Indx)), OK1, LL, LU,
|
|
Assume_Valid);
|
|
|
|
if OK1 then
|
|
Determine_Range
|
|
(Type_High_Bound (Etype (Indx)), OK1, UL, UU,
|
|
Assume_Valid);
|
|
|
|
if OK1 then
|
|
|
|
-- The maximum value for Length is the biggest
|
|
-- possible gap between the values of the bounds.
|
|
-- But of course, this value cannot be negative.
|
|
|
|
Hir := UI_Max (Uint_0, UU - LL + 1);
|
|
|
|
-- For constrained arrays, the minimum value for
|
|
-- Length is taken from the actual value of the
|
|
-- bounds, since the index will be exactly of this
|
|
-- subtype.
|
|
|
|
if Is_Constrained (Atyp) then
|
|
Lor := UI_Max (Uint_0, UL - LU + 1);
|
|
|
|
-- For an unconstrained array, the minimum value
|
|
-- for length is always zero.
|
|
|
|
else
|
|
Lor := Uint_0;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end;
|
|
|
|
-- No special handling for other attributes
|
|
-- Probably more opportunities exist here???
|
|
|
|
when others =>
|
|
OK1 := False;
|
|
|
|
end case;
|
|
|
|
-- For type conversion from one discrete type to another, we can
|
|
-- refine the range using the converted value.
|
|
|
|
when N_Type_Conversion =>
|
|
Determine_Range (Expression (N), OK1, Lor, Hir, Assume_Valid);
|
|
|
|
-- Nothing special to do for all other expression kinds
|
|
|
|
when others =>
|
|
OK1 := False;
|
|
Lor := No_Uint;
|
|
Hir := No_Uint;
|
|
end case;
|
|
|
|
-- At this stage, if OK1 is true, then we know that the actual result of
|
|
-- the computed expression is in the range Lor .. Hir. We can use this
|
|
-- to restrict the possible range of results.
|
|
|
|
if OK1 then
|
|
|
|
-- If the refined value of the low bound is greater than the type
|
|
-- low bound, then reset it to the more restrictive value. However,
|
|
-- we do NOT do this for the case of a modular type where the
|
|
-- possible upper bound on the value is above the base type high
|
|
-- bound, because that means the result could wrap.
|
|
|
|
if Lor > Lo
|
|
and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound)
|
|
then
|
|
Lo := Lor;
|
|
end if;
|
|
|
|
-- Similarly, if the refined value of the high bound is less than the
|
|
-- value so far, then reset it to the more restrictive value. Again,
|
|
-- we do not do this if the refined low bound is negative for a
|
|
-- modular type, since this would wrap.
|
|
|
|
if Hir < Hi
|
|
and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0)
|
|
then
|
|
Hi := Hir;
|
|
end if;
|
|
end if;
|
|
|
|
-- Set cache entry for future call and we are all done
|
|
|
|
Determine_Range_Cache_N (Cindex) := N;
|
|
Determine_Range_Cache_V (Cindex) := Assume_Valid;
|
|
Determine_Range_Cache_Lo (Cindex) := Lo;
|
|
Determine_Range_Cache_Hi (Cindex) := Hi;
|
|
return;
|
|
|
|
-- If any exception occurs, it means that we have some bug in the compiler,
|
|
-- possibly triggered by a previous error, or by some unforeseen peculiar
|
|
-- occurrence. However, this is only an optimization attempt, so there is
|
|
-- really no point in crashing the compiler. Instead we just decide, too
|
|
-- bad, we can't figure out a range in this case after all.
|
|
|
|
exception
|
|
when others =>
|
|
|
|
-- Debug flag K disables this behavior (useful for debugging)
|
|
|
|
if Debug_Flag_K then
|
|
raise;
|
|
else
|
|
OK := False;
|
|
Lo := No_Uint;
|
|
Hi := No_Uint;
|
|
return;
|
|
end if;
|
|
end Determine_Range;
|
|
|
|
-----------------------
|
|
-- Determine_Range_R --
|
|
-----------------------
|
|
|
|
procedure Determine_Range_R
|
|
(N : Node_Id;
|
|
OK : out Boolean;
|
|
Lo : out Ureal;
|
|
Hi : out Ureal;
|
|
Assume_Valid : Boolean := False)
|
|
is
|
|
Typ : Entity_Id := Etype (N);
|
|
-- Type to use, may get reset to base type for possibly invalid entity
|
|
|
|
Lo_Left : Ureal;
|
|
Hi_Left : Ureal;
|
|
-- Lo and Hi bounds of left operand
|
|
|
|
Lo_Right : Ureal;
|
|
Hi_Right : Ureal;
|
|
-- Lo and Hi bounds of right (or only) operand
|
|
|
|
Bound : Node_Id;
|
|
-- Temp variable used to hold a bound node
|
|
|
|
Hbound : Ureal;
|
|
-- High bound of base type of expression
|
|
|
|
Lor : Ureal;
|
|
Hir : Ureal;
|
|
-- Refined values for low and high bounds, after tightening
|
|
|
|
OK1 : Boolean;
|
|
-- Used in lower level calls to indicate if call succeeded
|
|
|
|
Cindex : Cache_Index;
|
|
-- Used to search cache
|
|
|
|
Btyp : Entity_Id;
|
|
-- Base type
|
|
|
|
function OK_Operands return Boolean;
|
|
-- Used for binary operators. Determines the ranges of the left and
|
|
-- right operands, and if they are both OK, returns True, and puts
|
|
-- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left.
|
|
|
|
function Round_Machine (B : Ureal) return Ureal;
|
|
-- B is a real bound. Round it using mode Round_Even.
|
|
|
|
-----------------
|
|
-- OK_Operands --
|
|
-----------------
|
|
|
|
function OK_Operands return Boolean is
|
|
begin
|
|
Determine_Range_R
|
|
(Left_Opnd (N), OK1, Lo_Left, Hi_Left, Assume_Valid);
|
|
|
|
if not OK1 then
|
|
return False;
|
|
end if;
|
|
|
|
Determine_Range_R
|
|
(Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid);
|
|
return OK1;
|
|
end OK_Operands;
|
|
|
|
-------------------
|
|
-- Round_Machine --
|
|
-------------------
|
|
|
|
function Round_Machine (B : Ureal) return Ureal is
|
|
begin
|
|
return Machine (Typ, B, Round_Even, N);
|
|
end Round_Machine;
|
|
|
|
-- Start of processing for Determine_Range_R
|
|
|
|
begin
|
|
-- Prevent junk warnings by initializing range variables
|
|
|
|
Lo := No_Ureal;
|
|
Hi := No_Ureal;
|
|
Lor := No_Ureal;
|
|
Hir := No_Ureal;
|
|
|
|
-- For temporary constants internally generated to remove side effects
|
|
-- we must use the corresponding expression to determine the range of
|
|
-- the expression. But note that the expander can also generate
|
|
-- constants in other cases, including deferred constants.
|
|
|
|
if Is_Entity_Name (N)
|
|
and then Nkind (Parent (Entity (N))) = N_Object_Declaration
|
|
and then Ekind (Entity (N)) = E_Constant
|
|
and then Is_Internal_Name (Chars (Entity (N)))
|
|
then
|
|
if Present (Expression (Parent (Entity (N)))) then
|
|
Determine_Range_R
|
|
(Expression (Parent (Entity (N))), OK, Lo, Hi, Assume_Valid);
|
|
|
|
elsif Present (Full_View (Entity (N))) then
|
|
Determine_Range_R
|
|
(Expression (Parent (Full_View (Entity (N)))),
|
|
OK, Lo, Hi, Assume_Valid);
|
|
|
|
else
|
|
OK := False;
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- If type is not defined, we can't determine its range
|
|
|
|
if No (Typ)
|
|
|
|
-- We don't deal with anything except IEEE floating-point types
|
|
|
|
or else not Is_Floating_Point_Type (Typ)
|
|
or else Float_Rep (Typ) /= IEEE_Binary
|
|
|
|
-- Ignore type for which an error has been posted, since range in
|
|
-- this case may well be a bogosity deriving from the error. Also
|
|
-- ignore if error posted on the reference node.
|
|
|
|
or else Error_Posted (N) or else Error_Posted (Typ)
|
|
then
|
|
OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- For all other cases, we can determine the range
|
|
|
|
OK := True;
|
|
|
|
-- If value is compile time known, then the possible range is the one
|
|
-- value that we know this expression definitely has.
|
|
|
|
if Compile_Time_Known_Value (N) then
|
|
Lo := Expr_Value_R (N);
|
|
Hi := Lo;
|
|
return;
|
|
end if;
|
|
|
|
-- Return if already in the cache
|
|
|
|
Cindex := Cache_Index (N mod Cache_Size);
|
|
|
|
if Determine_Range_Cache_N (Cindex) = N
|
|
and then
|
|
Determine_Range_Cache_V (Cindex) = Assume_Valid
|
|
then
|
|
Lo := Determine_Range_Cache_Lo_R (Cindex);
|
|
Hi := Determine_Range_Cache_Hi_R (Cindex);
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise, start by finding the bounds of the type of the expression,
|
|
-- the value cannot be outside this range (if it is, then we have an
|
|
-- overflow situation, which is a separate check, we are talking here
|
|
-- only about the expression value).
|
|
|
|
-- First a check, never try to find the bounds of a generic type, since
|
|
-- these bounds are always junk values, and it is only valid to look at
|
|
-- the bounds in an instance.
|
|
|
|
if Is_Generic_Type (Typ) then
|
|
OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- First step, change to use base type unless we know the value is valid
|
|
|
|
if (Is_Entity_Name (N) and then Is_Known_Valid (Entity (N)))
|
|
or else Assume_No_Invalid_Values
|
|
or else Assume_Valid
|
|
then
|
|
null;
|
|
else
|
|
Typ := Underlying_Type (Base_Type (Typ));
|
|
end if;
|
|
|
|
-- Retrieve the base type. Handle the case where the base type is a
|
|
-- private type.
|
|
|
|
Btyp := Base_Type (Typ);
|
|
|
|
if Is_Private_Type (Btyp) and then Present (Full_View (Btyp)) then
|
|
Btyp := Full_View (Btyp);
|
|
end if;
|
|
|
|
-- We use the actual bound unless it is dynamic, in which case use the
|
|
-- corresponding base type bound if possible. If we can't get a bound
|
|
-- then we figure we can't determine the range (a peculiar case, that
|
|
-- perhaps cannot happen, but there is no point in bombing in this
|
|
-- optimization circuit).
|
|
|
|
-- First the low bound
|
|
|
|
Bound := Type_Low_Bound (Typ);
|
|
|
|
if Compile_Time_Known_Value (Bound) then
|
|
Lo := Expr_Value_R (Bound);
|
|
|
|
elsif Compile_Time_Known_Value (Type_Low_Bound (Btyp)) then
|
|
Lo := Expr_Value_R (Type_Low_Bound (Btyp));
|
|
|
|
else
|
|
OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- Now the high bound
|
|
|
|
Bound := Type_High_Bound (Typ);
|
|
|
|
-- We need the high bound of the base type later on, and this should
|
|
-- always be compile time known. Again, it is not clear that this
|
|
-- can ever be false, but no point in bombing.
|
|
|
|
if Compile_Time_Known_Value (Type_High_Bound (Btyp)) then
|
|
Hbound := Expr_Value_R (Type_High_Bound (Btyp));
|
|
Hi := Hbound;
|
|
|
|
else
|
|
OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- If we have a static subtype, then that may have a tighter bound so
|
|
-- use the upper bound of the subtype instead in this case.
|
|
|
|
if Compile_Time_Known_Value (Bound) then
|
|
Hi := Expr_Value_R (Bound);
|
|
end if;
|
|
|
|
-- We may be able to refine this value in certain situations. If any
|
|
-- refinement is possible, then Lor and Hir are set to possibly tighter
|
|
-- bounds, and OK1 is set to True.
|
|
|
|
case Nkind (N) is
|
|
|
|
-- For unary plus, result is limited by range of operand
|
|
|
|
when N_Op_Plus =>
|
|
Determine_Range_R
|
|
(Right_Opnd (N), OK1, Lor, Hir, Assume_Valid);
|
|
|
|
-- For unary minus, determine range of operand, and negate it
|
|
|
|
when N_Op_Minus =>
|
|
Determine_Range_R
|
|
(Right_Opnd (N), OK1, Lo_Right, Hi_Right, Assume_Valid);
|
|
|
|
if OK1 then
|
|
Lor := -Hi_Right;
|
|
Hir := -Lo_Right;
|
|
end if;
|
|
|
|
-- For binary addition, get range of each operand and do the
|
|
-- addition to get the result range.
|
|
|
|
when N_Op_Add =>
|
|
if OK_Operands then
|
|
Lor := Round_Machine (Lo_Left + Lo_Right);
|
|
Hir := Round_Machine (Hi_Left + Hi_Right);
|
|
end if;
|
|
|
|
-- For binary subtraction, get range of each operand and do the worst
|
|
-- case subtraction to get the result range.
|
|
|
|
when N_Op_Subtract =>
|
|
if OK_Operands then
|
|
Lor := Round_Machine (Lo_Left - Hi_Right);
|
|
Hir := Round_Machine (Hi_Left - Lo_Right);
|
|
end if;
|
|
|
|
-- For multiplication, get range of each operand and do the
|
|
-- four multiplications to get the result range.
|
|
|
|
when N_Op_Multiply =>
|
|
if OK_Operands then
|
|
declare
|
|
M1 : constant Ureal := Round_Machine (Lo_Left * Lo_Right);
|
|
M2 : constant Ureal := Round_Machine (Lo_Left * Hi_Right);
|
|
M3 : constant Ureal := Round_Machine (Hi_Left * Lo_Right);
|
|
M4 : constant Ureal := Round_Machine (Hi_Left * Hi_Right);
|
|
begin
|
|
Lor := UR_Min (UR_Min (M1, M2), UR_Min (M3, M4));
|
|
Hir := UR_Max (UR_Max (M1, M2), UR_Max (M3, M4));
|
|
end;
|
|
end if;
|
|
|
|
-- For division, consider separately the cases where the right
|
|
-- operand is positive or negative. Otherwise, the right operand
|
|
-- can be arbitrarily close to zero, so the result is likely to
|
|
-- be unbounded in one direction, do not attempt to compute it.
|
|
|
|
when N_Op_Divide =>
|
|
if OK_Operands then
|
|
|
|
-- Right operand is positive
|
|
|
|
if Lo_Right > Ureal_0 then
|
|
|
|
-- If the low bound of the left operand is negative, obtain
|
|
-- the overall low bound by dividing it by the smallest
|
|
-- value of the right operand, and otherwise by the largest
|
|
-- value of the right operand.
|
|
|
|
if Lo_Left < Ureal_0 then
|
|
Lor := Round_Machine (Lo_Left / Lo_Right);
|
|
else
|
|
Lor := Round_Machine (Lo_Left / Hi_Right);
|
|
end if;
|
|
|
|
-- If the high bound of the left operand is negative, obtain
|
|
-- the overall high bound by dividing it by the largest
|
|
-- value of the right operand, and otherwise by the
|
|
-- smallest value of the right operand.
|
|
|
|
if Hi_Left < Ureal_0 then
|
|
Hir := Round_Machine (Hi_Left / Hi_Right);
|
|
else
|
|
Hir := Round_Machine (Hi_Left / Lo_Right);
|
|
end if;
|
|
|
|
-- Right operand is negative
|
|
|
|
elsif Hi_Right < Ureal_0 then
|
|
|
|
-- If the low bound of the left operand is negative, obtain
|
|
-- the overall low bound by dividing it by the largest
|
|
-- value of the right operand, and otherwise by the smallest
|
|
-- value of the right operand.
|
|
|
|
if Lo_Left < Ureal_0 then
|
|
Lor := Round_Machine (Lo_Left / Hi_Right);
|
|
else
|
|
Lor := Round_Machine (Lo_Left / Lo_Right);
|
|
end if;
|
|
|
|
-- If the high bound of the left operand is negative, obtain
|
|
-- the overall high bound by dividing it by the smallest
|
|
-- value of the right operand, and otherwise by the
|
|
-- largest value of the right operand.
|
|
|
|
if Hi_Left < Ureal_0 then
|
|
Hir := Round_Machine (Hi_Left / Lo_Right);
|
|
else
|
|
Hir := Round_Machine (Hi_Left / Hi_Right);
|
|
end if;
|
|
|
|
else
|
|
OK1 := False;
|
|
end if;
|
|
end if;
|
|
|
|
-- For type conversion from one floating-point type to another, we
|
|
-- can refine the range using the converted value.
|
|
|
|
when N_Type_Conversion =>
|
|
Determine_Range_R (Expression (N), OK1, Lor, Hir, Assume_Valid);
|
|
|
|
-- Nothing special to do for all other expression kinds
|
|
|
|
when others =>
|
|
OK1 := False;
|
|
Lor := No_Ureal;
|
|
Hir := No_Ureal;
|
|
end case;
|
|
|
|
-- At this stage, if OK1 is true, then we know that the actual result of
|
|
-- the computed expression is in the range Lor .. Hir. We can use this
|
|
-- to restrict the possible range of results.
|
|
|
|
if OK1 then
|
|
|
|
-- If the refined value of the low bound is greater than the type
|
|
-- low bound, then reset it to the more restrictive value.
|
|
|
|
if Lor > Lo then
|
|
Lo := Lor;
|
|
end if;
|
|
|
|
-- Similarly, if the refined value of the high bound is less than the
|
|
-- value so far, then reset it to the more restrictive value.
|
|
|
|
if Hir < Hi then
|
|
Hi := Hir;
|
|
end if;
|
|
end if;
|
|
|
|
-- Set cache entry for future call and we are all done
|
|
|
|
Determine_Range_Cache_N (Cindex) := N;
|
|
Determine_Range_Cache_V (Cindex) := Assume_Valid;
|
|
Determine_Range_Cache_Lo_R (Cindex) := Lo;
|
|
Determine_Range_Cache_Hi_R (Cindex) := Hi;
|
|
return;
|
|
|
|
-- If any exception occurs, it means that we have some bug in the compiler,
|
|
-- possibly triggered by a previous error, or by some unforeseen peculiar
|
|
-- occurrence. However, this is only an optimization attempt, so there is
|
|
-- really no point in crashing the compiler. Instead we just decide, too
|
|
-- bad, we can't figure out a range in this case after all.
|
|
|
|
exception
|
|
when others =>
|
|
|
|
-- Debug flag K disables this behavior (useful for debugging)
|
|
|
|
if Debug_Flag_K then
|
|
raise;
|
|
else
|
|
OK := False;
|
|
Lo := No_Ureal;
|
|
Hi := No_Ureal;
|
|
return;
|
|
end if;
|
|
end Determine_Range_R;
|
|
|
|
------------------------------------
|
|
-- Discriminant_Checks_Suppressed --
|
|
------------------------------------
|
|
|
|
function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) then
|
|
if Is_Unchecked_Union (E) then
|
|
return True;
|
|
elsif Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Discriminant_Check);
|
|
end if;
|
|
end if;
|
|
|
|
return Scope_Suppress.Suppress (Discriminant_Check);
|
|
end Discriminant_Checks_Suppressed;
|
|
|
|
--------------------------------
|
|
-- Division_Checks_Suppressed --
|
|
--------------------------------
|
|
|
|
function Division_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) and then Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Division_Check);
|
|
else
|
|
return Scope_Suppress.Suppress (Division_Check);
|
|
end if;
|
|
end Division_Checks_Suppressed;
|
|
|
|
--------------------------------------
|
|
-- Duplicated_Tag_Checks_Suppressed --
|
|
--------------------------------------
|
|
|
|
function Duplicated_Tag_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) and then Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Duplicated_Tag_Check);
|
|
else
|
|
return Scope_Suppress.Suppress (Duplicated_Tag_Check);
|
|
end if;
|
|
end Duplicated_Tag_Checks_Suppressed;
|
|
|
|
-----------------------------------
|
|
-- Elaboration_Checks_Suppressed --
|
|
-----------------------------------
|
|
|
|
function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
-- The complication in this routine is that if we are in the dynamic
|
|
-- model of elaboration, we also check All_Checks, since All_Checks
|
|
-- does not set Elaboration_Check explicitly.
|
|
|
|
if Present (E) then
|
|
if Kill_Elaboration_Checks (E) then
|
|
return True;
|
|
|
|
elsif Checks_May_Be_Suppressed (E) then
|
|
if Is_Check_Suppressed (E, Elaboration_Check) then
|
|
return True;
|
|
elsif Dynamic_Elaboration_Checks then
|
|
return Is_Check_Suppressed (E, All_Checks);
|
|
else
|
|
return False;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
|
|
if Scope_Suppress.Suppress (Elaboration_Check) then
|
|
return True;
|
|
elsif Dynamic_Elaboration_Checks then
|
|
return Scope_Suppress.Suppress (All_Checks);
|
|
else
|
|
return False;
|
|
end if;
|
|
end Elaboration_Checks_Suppressed;
|
|
|
|
---------------------------
|
|
-- Enable_Overflow_Check --
|
|
---------------------------
|
|
|
|
procedure Enable_Overflow_Check (N : Node_Id) is
|
|
Typ : constant Entity_Id := Base_Type (Etype (N));
|
|
Mode : constant Overflow_Mode_Type := Overflow_Check_Mode;
|
|
Chk : Nat;
|
|
OK : Boolean;
|
|
Ent : Entity_Id;
|
|
Ofs : Uint;
|
|
Lo : Uint;
|
|
Hi : Uint;
|
|
|
|
Do_Ovflow_Check : Boolean;
|
|
|
|
begin
|
|
if Debug_Flag_CC then
|
|
w ("Enable_Overflow_Check for node ", Int (N));
|
|
Write_Str (" Source location = ");
|
|
wl (Sloc (N));
|
|
pg (Union_Id (N));
|
|
end if;
|
|
|
|
-- No check if overflow checks suppressed for type of node
|
|
|
|
if Overflow_Checks_Suppressed (Etype (N)) then
|
|
return;
|
|
|
|
-- Nothing to do for unsigned integer types, which do not overflow
|
|
|
|
elsif Is_Modular_Integer_Type (Typ) then
|
|
return;
|
|
end if;
|
|
|
|
-- This is the point at which processing for STRICT mode diverges
|
|
-- from processing for MINIMIZED/ELIMINATED modes. This divergence is
|
|
-- probably more extreme that it needs to be, but what is going on here
|
|
-- is that when we introduced MINIMIZED/ELIMINATED modes, we wanted
|
|
-- to leave the processing for STRICT mode untouched. There were
|
|
-- two reasons for this. First it avoided any incompatible change of
|
|
-- behavior. Second, it guaranteed that STRICT mode continued to be
|
|
-- legacy reliable.
|
|
|
|
-- The big difference is that in STRICT mode there is a fair amount of
|
|
-- circuitry to try to avoid setting the Do_Overflow_Check flag if we
|
|
-- know that no check is needed. We skip all that in the two new modes,
|
|
-- since really overflow checking happens over a whole subtree, and we
|
|
-- do the corresponding optimizations later on when applying the checks.
|
|
|
|
if Mode in Minimized_Or_Eliminated then
|
|
if not (Overflow_Checks_Suppressed (Etype (N)))
|
|
and then not (Is_Entity_Name (N)
|
|
and then Overflow_Checks_Suppressed (Entity (N)))
|
|
then
|
|
Activate_Overflow_Check (N);
|
|
end if;
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Minimized/Eliminated mode");
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- Remainder of processing is for STRICT case, and is unchanged from
|
|
-- earlier versions preceding the addition of MINIMIZED/ELIMINATED.
|
|
|
|
-- Nothing to do if the range of the result is known OK. We skip this
|
|
-- for conversions, since the caller already did the check, and in any
|
|
-- case the condition for deleting the check for a type conversion is
|
|
-- different.
|
|
|
|
if Nkind (N) /= N_Type_Conversion then
|
|
Determine_Range (N, OK, Lo, Hi, Assume_Valid => True);
|
|
|
|
-- Note in the test below that we assume that the range is not OK
|
|
-- if a bound of the range is equal to that of the type. That's not
|
|
-- quite accurate but we do this for the following reasons:
|
|
|
|
-- a) The way that Determine_Range works, it will typically report
|
|
-- the bounds of the value as being equal to the bounds of the
|
|
-- type, because it either can't tell anything more precise, or
|
|
-- does not think it is worth the effort to be more precise.
|
|
|
|
-- b) It is very unusual to have a situation in which this would
|
|
-- generate an unnecessary overflow check (an example would be
|
|
-- a subtype with a range 0 .. Integer'Last - 1 to which the
|
|
-- literal value one is added).
|
|
|
|
-- c) The alternative is a lot of special casing in this routine
|
|
-- which would partially duplicate Determine_Range processing.
|
|
|
|
if OK then
|
|
Do_Ovflow_Check := True;
|
|
|
|
-- Note that the following checks are quite deliberately > and <
|
|
-- rather than >= and <= as explained above.
|
|
|
|
if Lo > Expr_Value (Type_Low_Bound (Typ))
|
|
and then
|
|
Hi < Expr_Value (Type_High_Bound (Typ))
|
|
then
|
|
Do_Ovflow_Check := False;
|
|
|
|
-- Despite the comments above, it is worth dealing specially with
|
|
-- division specially. The only case where integer division can
|
|
-- overflow is (largest negative number) / (-1). So we will do
|
|
-- an extra range analysis to see if this is possible.
|
|
|
|
elsif Nkind (N) = N_Op_Divide then
|
|
Determine_Range
|
|
(Left_Opnd (N), OK, Lo, Hi, Assume_Valid => True);
|
|
|
|
if OK and then Lo > Expr_Value (Type_Low_Bound (Typ)) then
|
|
Do_Ovflow_Check := False;
|
|
|
|
else
|
|
Determine_Range
|
|
(Right_Opnd (N), OK, Lo, Hi, Assume_Valid => True);
|
|
|
|
if OK and then (Lo > Uint_Minus_1
|
|
or else
|
|
Hi < Uint_Minus_1)
|
|
then
|
|
Do_Ovflow_Check := False;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
|
|
-- If no overflow check required, we are done
|
|
|
|
if not Do_Ovflow_Check then
|
|
if Debug_Flag_CC then
|
|
w ("No overflow check required");
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
|
|
-- If not in optimizing mode, set flag and we are done. We are also done
|
|
-- (and just set the flag) if the type is not a discrete type, since it
|
|
-- is not worth the effort to eliminate checks for other than discrete
|
|
-- types. In addition, we take this same path if we have stored the
|
|
-- maximum number of checks possible already (a very unlikely situation,
|
|
-- but we do not want to blow up).
|
|
|
|
if Optimization_Level = 0
|
|
or else not Is_Discrete_Type (Etype (N))
|
|
or else Num_Saved_Checks = Saved_Checks'Last
|
|
then
|
|
Activate_Overflow_Check (N);
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Optimization off");
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise evaluate and check the expression
|
|
|
|
Find_Check
|
|
(Expr => N,
|
|
Check_Type => 'O',
|
|
Target_Type => Empty,
|
|
Entry_OK => OK,
|
|
Check_Num => Chk,
|
|
Ent => Ent,
|
|
Ofs => Ofs);
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Called Find_Check");
|
|
w (" OK = ", OK);
|
|
|
|
if OK then
|
|
w (" Check_Num = ", Chk);
|
|
w (" Ent = ", Int (Ent));
|
|
Write_Str (" Ofs = ");
|
|
pid (Ofs);
|
|
end if;
|
|
end if;
|
|
|
|
-- If check is not of form to optimize, then set flag and we are done
|
|
|
|
if not OK then
|
|
Activate_Overflow_Check (N);
|
|
return;
|
|
end if;
|
|
|
|
-- If check is already performed, then return without setting flag
|
|
|
|
if Chk /= 0 then
|
|
if Debug_Flag_CC then
|
|
w ("Check suppressed!");
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- Here we will make a new entry for the new check
|
|
|
|
Activate_Overflow_Check (N);
|
|
Num_Saved_Checks := Num_Saved_Checks + 1;
|
|
Saved_Checks (Num_Saved_Checks) :=
|
|
(Killed => False,
|
|
Entity => Ent,
|
|
Offset => Ofs,
|
|
Check_Type => 'O',
|
|
Target_Type => Empty);
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Make new entry, check number = ", Num_Saved_Checks);
|
|
w (" Entity = ", Int (Ent));
|
|
Write_Str (" Offset = ");
|
|
pid (Ofs);
|
|
w (" Check_Type = O");
|
|
w (" Target_Type = Empty");
|
|
end if;
|
|
|
|
-- If we get an exception, then something went wrong, probably because of
|
|
-- an error in the structure of the tree due to an incorrect program. Or
|
|
-- it may be a bug in the optimization circuit. In either case the safest
|
|
-- thing is simply to set the check flag unconditionally.
|
|
|
|
exception
|
|
when others =>
|
|
Activate_Overflow_Check (N);
|
|
|
|
if Debug_Flag_CC then
|
|
w (" exception occurred, overflow flag set");
|
|
end if;
|
|
|
|
return;
|
|
end Enable_Overflow_Check;
|
|
|
|
------------------------
|
|
-- Enable_Range_Check --
|
|
------------------------
|
|
|
|
procedure Enable_Range_Check (N : Node_Id) is
|
|
Chk : Nat;
|
|
OK : Boolean;
|
|
Ent : Entity_Id;
|
|
Ofs : Uint;
|
|
Ttyp : Entity_Id;
|
|
P : Node_Id;
|
|
|
|
begin
|
|
-- Return if unchecked type conversion with range check killed. In this
|
|
-- case we never set the flag (that's what Kill_Range_Check is about).
|
|
|
|
if Nkind (N) = N_Unchecked_Type_Conversion
|
|
and then Kill_Range_Check (N)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Do not set range check flag if parent is assignment statement or
|
|
-- object declaration with Suppress_Assignment_Checks flag set
|
|
|
|
if Nkind_In (Parent (N), N_Assignment_Statement, N_Object_Declaration)
|
|
and then Suppress_Assignment_Checks (Parent (N))
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Check for various cases where we should suppress the range check
|
|
|
|
-- No check if range checks suppressed for type of node
|
|
|
|
if Present (Etype (N)) and then Range_Checks_Suppressed (Etype (N)) then
|
|
return;
|
|
|
|
-- No check if node is an entity name, and range checks are suppressed
|
|
-- for this entity, or for the type of this entity.
|
|
|
|
elsif Is_Entity_Name (N)
|
|
and then (Range_Checks_Suppressed (Entity (N))
|
|
or else Range_Checks_Suppressed (Etype (Entity (N))))
|
|
then
|
|
return;
|
|
|
|
-- No checks if index of array, and index checks are suppressed for
|
|
-- the array object or the type of the array.
|
|
|
|
elsif Nkind (Parent (N)) = N_Indexed_Component then
|
|
declare
|
|
Pref : constant Node_Id := Prefix (Parent (N));
|
|
begin
|
|
if Is_Entity_Name (Pref)
|
|
and then Index_Checks_Suppressed (Entity (Pref))
|
|
then
|
|
return;
|
|
elsif Index_Checks_Suppressed (Etype (Pref)) then
|
|
return;
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
-- Debug trace output
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Enable_Range_Check for node ", Int (N));
|
|
Write_Str (" Source location = ");
|
|
wl (Sloc (N));
|
|
pg (Union_Id (N));
|
|
end if;
|
|
|
|
-- If not in optimizing mode, set flag and we are done. We are also done
|
|
-- (and just set the flag) if the type is not a discrete type, since it
|
|
-- is not worth the effort to eliminate checks for other than discrete
|
|
-- types. In addition, we take this same path if we have stored the
|
|
-- maximum number of checks possible already (a very unlikely situation,
|
|
-- but we do not want to blow up).
|
|
|
|
if Optimization_Level = 0
|
|
or else No (Etype (N))
|
|
or else not Is_Discrete_Type (Etype (N))
|
|
or else Num_Saved_Checks = Saved_Checks'Last
|
|
then
|
|
Activate_Range_Check (N);
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Optimization off");
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise find out the target type
|
|
|
|
P := Parent (N);
|
|
|
|
-- For assignment, use left side subtype
|
|
|
|
if Nkind (P) = N_Assignment_Statement
|
|
and then Expression (P) = N
|
|
then
|
|
Ttyp := Etype (Name (P));
|
|
|
|
-- For indexed component, use subscript subtype
|
|
|
|
elsif Nkind (P) = N_Indexed_Component then
|
|
declare
|
|
Atyp : Entity_Id;
|
|
Indx : Node_Id;
|
|
Subs : Node_Id;
|
|
|
|
begin
|
|
Atyp := Etype (Prefix (P));
|
|
|
|
if Is_Access_Type (Atyp) then
|
|
Atyp := Designated_Type (Atyp);
|
|
|
|
-- If the prefix is an access to an unconstrained array,
|
|
-- perform check unconditionally: it depends on the bounds of
|
|
-- an object and we cannot currently recognize whether the test
|
|
-- may be redundant.
|
|
|
|
if not Is_Constrained (Atyp) then
|
|
Activate_Range_Check (N);
|
|
return;
|
|
end if;
|
|
|
|
-- Ditto if prefix is simply an unconstrained array. We used
|
|
-- to think this case was OK, if the prefix was not an explicit
|
|
-- dereference, but we have now seen a case where this is not
|
|
-- true, so it is safer to just suppress the optimization in this
|
|
-- case. The back end is getting better at eliminating redundant
|
|
-- checks in any case, so the loss won't be important.
|
|
|
|
elsif Is_Array_Type (Atyp)
|
|
and then not Is_Constrained (Atyp)
|
|
then
|
|
Activate_Range_Check (N);
|
|
return;
|
|
end if;
|
|
|
|
Indx := First_Index (Atyp);
|
|
Subs := First (Expressions (P));
|
|
loop
|
|
if Subs = N then
|
|
Ttyp := Etype (Indx);
|
|
exit;
|
|
end if;
|
|
|
|
Next_Index (Indx);
|
|
Next (Subs);
|
|
end loop;
|
|
end;
|
|
|
|
-- For now, ignore all other cases, they are not so interesting
|
|
|
|
else
|
|
if Debug_Flag_CC then
|
|
w (" target type not found, flag set");
|
|
end if;
|
|
|
|
Activate_Range_Check (N);
|
|
return;
|
|
end if;
|
|
|
|
-- Evaluate and check the expression
|
|
|
|
Find_Check
|
|
(Expr => N,
|
|
Check_Type => 'R',
|
|
Target_Type => Ttyp,
|
|
Entry_OK => OK,
|
|
Check_Num => Chk,
|
|
Ent => Ent,
|
|
Ofs => Ofs);
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Called Find_Check");
|
|
w ("Target_Typ = ", Int (Ttyp));
|
|
w (" OK = ", OK);
|
|
|
|
if OK then
|
|
w (" Check_Num = ", Chk);
|
|
w (" Ent = ", Int (Ent));
|
|
Write_Str (" Ofs = ");
|
|
pid (Ofs);
|
|
end if;
|
|
end if;
|
|
|
|
-- If check is not of form to optimize, then set flag and we are done
|
|
|
|
if not OK then
|
|
if Debug_Flag_CC then
|
|
w (" expression not of optimizable type, flag set");
|
|
end if;
|
|
|
|
Activate_Range_Check (N);
|
|
return;
|
|
end if;
|
|
|
|
-- If check is already performed, then return without setting flag
|
|
|
|
if Chk /= 0 then
|
|
if Debug_Flag_CC then
|
|
w ("Check suppressed!");
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- Here we will make a new entry for the new check
|
|
|
|
Activate_Range_Check (N);
|
|
Num_Saved_Checks := Num_Saved_Checks + 1;
|
|
Saved_Checks (Num_Saved_Checks) :=
|
|
(Killed => False,
|
|
Entity => Ent,
|
|
Offset => Ofs,
|
|
Check_Type => 'R',
|
|
Target_Type => Ttyp);
|
|
|
|
if Debug_Flag_CC then
|
|
w ("Make new entry, check number = ", Num_Saved_Checks);
|
|
w (" Entity = ", Int (Ent));
|
|
Write_Str (" Offset = ");
|
|
pid (Ofs);
|
|
w (" Check_Type = R");
|
|
w (" Target_Type = ", Int (Ttyp));
|
|
pg (Union_Id (Ttyp));
|
|
end if;
|
|
|
|
-- If we get an exception, then something went wrong, probably because of
|
|
-- an error in the structure of the tree due to an incorrect program. Or
|
|
-- it may be a bug in the optimization circuit. In either case the safest
|
|
-- thing is simply to set the check flag unconditionally.
|
|
|
|
exception
|
|
when others =>
|
|
Activate_Range_Check (N);
|
|
|
|
if Debug_Flag_CC then
|
|
w (" exception occurred, range flag set");
|
|
end if;
|
|
|
|
return;
|
|
end Enable_Range_Check;
|
|
|
|
------------------
|
|
-- Ensure_Valid --
|
|
------------------
|
|
|
|
procedure Ensure_Valid
|
|
(Expr : Node_Id;
|
|
Holes_OK : Boolean := False;
|
|
Related_Id : Entity_Id := Empty;
|
|
Is_Low_Bound : Boolean := False;
|
|
Is_High_Bound : Boolean := False)
|
|
is
|
|
Typ : constant Entity_Id := Etype (Expr);
|
|
|
|
begin
|
|
-- Ignore call if we are not doing any validity checking
|
|
|
|
if not Validity_Checks_On then
|
|
return;
|
|
|
|
-- Ignore call if range or validity checks suppressed on entity or type
|
|
|
|
elsif Range_Or_Validity_Checks_Suppressed (Expr) then
|
|
return;
|
|
|
|
-- No check required if expression is from the expander, we assume the
|
|
-- expander will generate whatever checks are needed. Note that this is
|
|
-- not just an optimization, it avoids infinite recursions.
|
|
|
|
-- Unchecked conversions must be checked, unless they are initialized
|
|
-- scalar values, as in a component assignment in an init proc.
|
|
|
|
-- In addition, we force a check if Force_Validity_Checks is set
|
|
|
|
elsif not Comes_From_Source (Expr)
|
|
and then not Force_Validity_Checks
|
|
and then (Nkind (Expr) /= N_Unchecked_Type_Conversion
|
|
or else Kill_Range_Check (Expr))
|
|
then
|
|
return;
|
|
|
|
-- No check required if expression is known to have valid value
|
|
|
|
elsif Expr_Known_Valid (Expr) then
|
|
return;
|
|
|
|
-- Ignore case of enumeration with holes where the flag is set not to
|
|
-- worry about holes, since no special validity check is needed
|
|
|
|
elsif Is_Enumeration_Type (Typ)
|
|
and then Has_Non_Standard_Rep (Typ)
|
|
and then Holes_OK
|
|
then
|
|
return;
|
|
|
|
-- No check required on the left-hand side of an assignment
|
|
|
|
elsif Nkind (Parent (Expr)) = N_Assignment_Statement
|
|
and then Expr = Name (Parent (Expr))
|
|
then
|
|
return;
|
|
|
|
-- No check on a universal real constant. The context will eventually
|
|
-- convert it to a machine number for some target type, or report an
|
|
-- illegality.
|
|
|
|
elsif Nkind (Expr) = N_Real_Literal
|
|
and then Etype (Expr) = Universal_Real
|
|
then
|
|
return;
|
|
|
|
-- If the expression denotes a component of a packed boolean array,
|
|
-- no possible check applies. We ignore the old ACATS chestnuts that
|
|
-- involve Boolean range True..True.
|
|
|
|
-- Note: validity checks are generated for expressions that yield a
|
|
-- scalar type, when it is possible to create a value that is outside of
|
|
-- the type. If this is a one-bit boolean no such value exists. This is
|
|
-- an optimization, and it also prevents compiler blowing up during the
|
|
-- elaboration of improperly expanded packed array references.
|
|
|
|
elsif Nkind (Expr) = N_Indexed_Component
|
|
and then Is_Bit_Packed_Array (Etype (Prefix (Expr)))
|
|
and then Root_Type (Etype (Expr)) = Standard_Boolean
|
|
then
|
|
return;
|
|
|
|
-- For an expression with actions, we want to insert the validity check
|
|
-- on the final Expression.
|
|
|
|
elsif Nkind (Expr) = N_Expression_With_Actions then
|
|
Ensure_Valid (Expression (Expr));
|
|
return;
|
|
|
|
-- An annoying special case. If this is an out parameter of a scalar
|
|
-- type, then the value is not going to be accessed, therefore it is
|
|
-- inappropriate to do any validity check at the call site.
|
|
|
|
else
|
|
-- Only need to worry about scalar types
|
|
|
|
if Is_Scalar_Type (Typ) then
|
|
declare
|
|
P : Node_Id;
|
|
N : Node_Id;
|
|
E : Entity_Id;
|
|
F : Entity_Id;
|
|
A : Node_Id;
|
|
L : List_Id;
|
|
|
|
begin
|
|
-- Find actual argument (which may be a parameter association)
|
|
-- and the parent of the actual argument (the call statement)
|
|
|
|
N := Expr;
|
|
P := Parent (Expr);
|
|
|
|
if Nkind (P) = N_Parameter_Association then
|
|
N := P;
|
|
P := Parent (N);
|
|
end if;
|
|
|
|
-- Only need to worry if we are argument of a procedure call
|
|
-- since functions don't have out parameters. If this is an
|
|
-- indirect or dispatching call, get signature from the
|
|
-- subprogram type.
|
|
|
|
if Nkind (P) = N_Procedure_Call_Statement then
|
|
L := Parameter_Associations (P);
|
|
|
|
if Is_Entity_Name (Name (P)) then
|
|
E := Entity (Name (P));
|
|
else
|
|
pragma Assert (Nkind (Name (P)) = N_Explicit_Dereference);
|
|
E := Etype (Name (P));
|
|
end if;
|
|
|
|
-- Only need to worry if there are indeed actuals, and if
|
|
-- this could be a procedure call, otherwise we cannot get a
|
|
-- match (either we are not an argument, or the mode of the
|
|
-- formal is not OUT). This test also filters out the
|
|
-- generic case.
|
|
|
|
if Is_Non_Empty_List (L) and then Is_Subprogram (E) then
|
|
|
|
-- This is the loop through parameters, looking for an
|
|
-- OUT parameter for which we are the argument.
|
|
|
|
F := First_Formal (E);
|
|
A := First (L);
|
|
while Present (F) loop
|
|
if Ekind (F) = E_Out_Parameter and then A = N then
|
|
return;
|
|
end if;
|
|
|
|
Next_Formal (F);
|
|
Next (A);
|
|
end loop;
|
|
end if;
|
|
end if;
|
|
end;
|
|
end if;
|
|
end if;
|
|
|
|
-- If this is a boolean expression, only its elementary operands need
|
|
-- checking: if they are valid, a boolean or short-circuit operation
|
|
-- with them will be valid as well.
|
|
|
|
if Base_Type (Typ) = Standard_Boolean
|
|
and then
|
|
(Nkind (Expr) in N_Op or else Nkind (Expr) in N_Short_Circuit)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- If we fall through, a validity check is required
|
|
|
|
Insert_Valid_Check (Expr, Related_Id, Is_Low_Bound, Is_High_Bound);
|
|
|
|
if Is_Entity_Name (Expr)
|
|
and then Safe_To_Capture_Value (Expr, Entity (Expr))
|
|
then
|
|
Set_Is_Known_Valid (Entity (Expr));
|
|
end if;
|
|
end Ensure_Valid;
|
|
|
|
----------------------
|
|
-- Expr_Known_Valid --
|
|
----------------------
|
|
|
|
function Expr_Known_Valid (Expr : Node_Id) return Boolean is
|
|
Typ : constant Entity_Id := Etype (Expr);
|
|
|
|
begin
|
|
-- Non-scalar types are always considered valid, since they never give
|
|
-- rise to the issues of erroneous or bounded error behavior that are
|
|
-- the concern. In formal reference manual terms the notion of validity
|
|
-- only applies to scalar types. Note that even when packed arrays are
|
|
-- represented using modular types, they are still arrays semantically,
|
|
-- so they are also always valid (in particular, the unused bits can be
|
|
-- random rubbish without affecting the validity of the array value).
|
|
|
|
if not Is_Scalar_Type (Typ) or else Is_Packed_Array_Impl_Type (Typ) then
|
|
return True;
|
|
|
|
-- If no validity checking, then everything is considered valid
|
|
|
|
elsif not Validity_Checks_On then
|
|
return True;
|
|
|
|
-- Floating-point types are considered valid unless floating-point
|
|
-- validity checks have been specifically turned on.
|
|
|
|
elsif Is_Floating_Point_Type (Typ)
|
|
and then not Validity_Check_Floating_Point
|
|
then
|
|
return True;
|
|
|
|
-- If the expression is the value of an object that is known to be
|
|
-- valid, then clearly the expression value itself is valid.
|
|
|
|
elsif Is_Entity_Name (Expr)
|
|
and then Is_Known_Valid (Entity (Expr))
|
|
|
|
-- Exclude volatile variables
|
|
|
|
and then not Treat_As_Volatile (Entity (Expr))
|
|
then
|
|
return True;
|
|
|
|
-- References to discriminants are always considered valid. The value
|
|
-- of a discriminant gets checked when the object is built. Within the
|
|
-- record, we consider it valid, and it is important to do so, since
|
|
-- otherwise we can try to generate bogus validity checks which
|
|
-- reference discriminants out of scope. Discriminants of concurrent
|
|
-- types are excluded for the same reason.
|
|
|
|
elsif Is_Entity_Name (Expr)
|
|
and then Denotes_Discriminant (Expr, Check_Concurrent => True)
|
|
then
|
|
return True;
|
|
|
|
-- If the type is one for which all values are known valid, then we are
|
|
-- sure that the value is valid except in the slightly odd case where
|
|
-- the expression is a reference to a variable whose size has been
|
|
-- explicitly set to a value greater than the object size.
|
|
|
|
elsif Is_Known_Valid (Typ) then
|
|
if Is_Entity_Name (Expr)
|
|
and then Ekind (Entity (Expr)) = E_Variable
|
|
and then Esize (Entity (Expr)) > Esize (Typ)
|
|
then
|
|
return False;
|
|
else
|
|
return True;
|
|
end if;
|
|
|
|
-- Integer and character literals always have valid values, where
|
|
-- appropriate these will be range checked in any case.
|
|
|
|
elsif Nkind_In (Expr, N_Integer_Literal, N_Character_Literal) then
|
|
return True;
|
|
|
|
-- If we have a type conversion or a qualification of a known valid
|
|
-- value, then the result will always be valid.
|
|
|
|
elsif Nkind_In (Expr, N_Type_Conversion, N_Qualified_Expression) then
|
|
return Expr_Known_Valid (Expression (Expr));
|
|
|
|
-- Case of expression is a non-floating-point operator. In this case we
|
|
-- can assume the result is valid the generated code for the operator
|
|
-- will include whatever checks are needed (e.g. range checks) to ensure
|
|
-- validity. This assumption does not hold for the floating-point case,
|
|
-- since floating-point operators can generate Infinite or NaN results
|
|
-- which are considered invalid.
|
|
|
|
-- Historical note: in older versions, the exemption of floating-point
|
|
-- types from this assumption was done only in cases where the parent
|
|
-- was an assignment, function call or parameter association. Presumably
|
|
-- the idea was that in other contexts, the result would be checked
|
|
-- elsewhere, but this list of cases was missing tests (at least the
|
|
-- N_Object_Declaration case, as shown by a reported missing validity
|
|
-- check), and it is not clear why function calls but not procedure
|
|
-- calls were tested for. It really seems more accurate and much
|
|
-- safer to recognize that expressions which are the result of a
|
|
-- floating-point operator can never be assumed to be valid.
|
|
|
|
elsif Nkind (Expr) in N_Op and then not Is_Floating_Point_Type (Typ) then
|
|
return True;
|
|
|
|
-- The result of a membership test is always valid, since it is true or
|
|
-- false, there are no other possibilities.
|
|
|
|
elsif Nkind (Expr) in N_Membership_Test then
|
|
return True;
|
|
|
|
-- For all other cases, we do not know the expression is valid
|
|
|
|
else
|
|
return False;
|
|
end if;
|
|
end Expr_Known_Valid;
|
|
|
|
----------------
|
|
-- Find_Check --
|
|
----------------
|
|
|
|
procedure Find_Check
|
|
(Expr : Node_Id;
|
|
Check_Type : Character;
|
|
Target_Type : Entity_Id;
|
|
Entry_OK : out Boolean;
|
|
Check_Num : out Nat;
|
|
Ent : out Entity_Id;
|
|
Ofs : out Uint)
|
|
is
|
|
function Within_Range_Of
|
|
(Target_Type : Entity_Id;
|
|
Check_Type : Entity_Id) return Boolean;
|
|
-- Given a requirement for checking a range against Target_Type, and
|
|
-- and a range Check_Type against which a check has already been made,
|
|
-- determines if the check against check type is sufficient to ensure
|
|
-- that no check against Target_Type is required.
|
|
|
|
---------------------
|
|
-- Within_Range_Of --
|
|
---------------------
|
|
|
|
function Within_Range_Of
|
|
(Target_Type : Entity_Id;
|
|
Check_Type : Entity_Id) return Boolean
|
|
is
|
|
begin
|
|
if Target_Type = Check_Type then
|
|
return True;
|
|
|
|
else
|
|
declare
|
|
Tlo : constant Node_Id := Type_Low_Bound (Target_Type);
|
|
Thi : constant Node_Id := Type_High_Bound (Target_Type);
|
|
Clo : constant Node_Id := Type_Low_Bound (Check_Type);
|
|
Chi : constant Node_Id := Type_High_Bound (Check_Type);
|
|
|
|
begin
|
|
if (Tlo = Clo
|
|
or else (Compile_Time_Known_Value (Tlo)
|
|
and then
|
|
Compile_Time_Known_Value (Clo)
|
|
and then
|
|
Expr_Value (Clo) >= Expr_Value (Tlo)))
|
|
and then
|
|
(Thi = Chi
|
|
or else (Compile_Time_Known_Value (Thi)
|
|
and then
|
|
Compile_Time_Known_Value (Chi)
|
|
and then
|
|
Expr_Value (Chi) <= Expr_Value (Clo)))
|
|
then
|
|
return True;
|
|
else
|
|
return False;
|
|
end if;
|
|
end;
|
|
end if;
|
|
end Within_Range_Of;
|
|
|
|
-- Start of processing for Find_Check
|
|
|
|
begin
|
|
-- Establish default, in case no entry is found
|
|
|
|
Check_Num := 0;
|
|
|
|
-- Case of expression is simple entity reference
|
|
|
|
if Is_Entity_Name (Expr) then
|
|
Ent := Entity (Expr);
|
|
Ofs := Uint_0;
|
|
|
|
-- Case of expression is entity + known constant
|
|
|
|
elsif Nkind (Expr) = N_Op_Add
|
|
and then Compile_Time_Known_Value (Right_Opnd (Expr))
|
|
and then Is_Entity_Name (Left_Opnd (Expr))
|
|
then
|
|
Ent := Entity (Left_Opnd (Expr));
|
|
Ofs := Expr_Value (Right_Opnd (Expr));
|
|
|
|
-- Case of expression is entity - known constant
|
|
|
|
elsif Nkind (Expr) = N_Op_Subtract
|
|
and then Compile_Time_Known_Value (Right_Opnd (Expr))
|
|
and then Is_Entity_Name (Left_Opnd (Expr))
|
|
then
|
|
Ent := Entity (Left_Opnd (Expr));
|
|
Ofs := UI_Negate (Expr_Value (Right_Opnd (Expr)));
|
|
|
|
-- Any other expression is not of the right form
|
|
|
|
else
|
|
Ent := Empty;
|
|
Ofs := Uint_0;
|
|
Entry_OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- Come here with expression of appropriate form, check if entity is an
|
|
-- appropriate one for our purposes.
|
|
|
|
if (Ekind (Ent) = E_Variable
|
|
or else Is_Constant_Object (Ent))
|
|
and then not Is_Library_Level_Entity (Ent)
|
|
then
|
|
Entry_OK := True;
|
|
else
|
|
Entry_OK := False;
|
|
return;
|
|
end if;
|
|
|
|
-- See if there is matching check already
|
|
|
|
for J in reverse 1 .. Num_Saved_Checks loop
|
|
declare
|
|
SC : Saved_Check renames Saved_Checks (J);
|
|
begin
|
|
if SC.Killed = False
|
|
and then SC.Entity = Ent
|
|
and then SC.Offset = Ofs
|
|
and then SC.Check_Type = Check_Type
|
|
and then Within_Range_Of (Target_Type, SC.Target_Type)
|
|
then
|
|
Check_Num := J;
|
|
return;
|
|
end if;
|
|
end;
|
|
end loop;
|
|
|
|
-- If we fall through entry was not found
|
|
|
|
return;
|
|
end Find_Check;
|
|
|
|
---------------------------------
|
|
-- Generate_Discriminant_Check --
|
|
---------------------------------
|
|
|
|
-- Note: the code for this procedure is derived from the
|
|
-- Emit_Discriminant_Check Routine in trans.c.
|
|
|
|
procedure Generate_Discriminant_Check (N : Node_Id) is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Pref : constant Node_Id := Prefix (N);
|
|
Sel : constant Node_Id := Selector_Name (N);
|
|
|
|
Orig_Comp : constant Entity_Id :=
|
|
Original_Record_Component (Entity (Sel));
|
|
-- The original component to be checked
|
|
|
|
Discr_Fct : constant Entity_Id :=
|
|
Discriminant_Checking_Func (Orig_Comp);
|
|
-- The discriminant checking function
|
|
|
|
Discr : Entity_Id;
|
|
-- One discriminant to be checked in the type
|
|
|
|
Real_Discr : Entity_Id;
|
|
-- Actual discriminant in the call
|
|
|
|
Pref_Type : Entity_Id;
|
|
-- Type of relevant prefix (ignoring private/access stuff)
|
|
|
|
Args : List_Id;
|
|
-- List of arguments for function call
|
|
|
|
Formal : Entity_Id;
|
|
-- Keep track of the formal corresponding to the actual we build for
|
|
-- each discriminant, in order to be able to perform the necessary type
|
|
-- conversions.
|
|
|
|
Scomp : Node_Id;
|
|
-- Selected component reference for checking function argument
|
|
|
|
begin
|
|
Pref_Type := Etype (Pref);
|
|
|
|
-- Force evaluation of the prefix, so that it does not get evaluated
|
|
-- twice (once for the check, once for the actual reference). Such a
|
|
-- double evaluation is always a potential source of inefficiency, and
|
|
-- is functionally incorrect in the volatile case, or when the prefix
|
|
-- may have side effects. A nonvolatile entity or a component of a
|
|
-- nonvolatile entity requires no evaluation.
|
|
|
|
if Is_Entity_Name (Pref) then
|
|
if Treat_As_Volatile (Entity (Pref)) then
|
|
Force_Evaluation (Pref, Name_Req => True);
|
|
end if;
|
|
|
|
elsif Treat_As_Volatile (Etype (Pref)) then
|
|
Force_Evaluation (Pref, Name_Req => True);
|
|
|
|
elsif Nkind (Pref) = N_Selected_Component
|
|
and then Is_Entity_Name (Prefix (Pref))
|
|
then
|
|
null;
|
|
|
|
else
|
|
Force_Evaluation (Pref, Name_Req => True);
|
|
end if;
|
|
|
|
-- For a tagged type, use the scope of the original component to
|
|
-- obtain the type, because ???
|
|
|
|
if Is_Tagged_Type (Scope (Orig_Comp)) then
|
|
Pref_Type := Scope (Orig_Comp);
|
|
|
|
-- For an untagged derived type, use the discriminants of the parent
|
|
-- which have been renamed in the derivation, possibly by a one-to-many
|
|
-- discriminant constraint. For untagged type, initially get the Etype
|
|
-- of the prefix
|
|
|
|
else
|
|
if Is_Derived_Type (Pref_Type)
|
|
and then Number_Discriminants (Pref_Type) /=
|
|
Number_Discriminants (Etype (Base_Type (Pref_Type)))
|
|
then
|
|
Pref_Type := Etype (Base_Type (Pref_Type));
|
|
end if;
|
|
end if;
|
|
|
|
-- We definitely should have a checking function, This routine should
|
|
-- not be called if no discriminant checking function is present.
|
|
|
|
pragma Assert (Present (Discr_Fct));
|
|
|
|
-- Create the list of the actual parameters for the call. This list
|
|
-- is the list of the discriminant fields of the record expression to
|
|
-- be discriminant checked.
|
|
|
|
Args := New_List;
|
|
Formal := First_Formal (Discr_Fct);
|
|
Discr := First_Discriminant (Pref_Type);
|
|
while Present (Discr) loop
|
|
|
|
-- If we have a corresponding discriminant field, and a parent
|
|
-- subtype is present, then we want to use the corresponding
|
|
-- discriminant since this is the one with the useful value.
|
|
|
|
if Present (Corresponding_Discriminant (Discr))
|
|
and then Ekind (Pref_Type) = E_Record_Type
|
|
and then Present (Parent_Subtype (Pref_Type))
|
|
then
|
|
Real_Discr := Corresponding_Discriminant (Discr);
|
|
else
|
|
Real_Discr := Discr;
|
|
end if;
|
|
|
|
-- Construct the reference to the discriminant
|
|
|
|
Scomp :=
|
|
Make_Selected_Component (Loc,
|
|
Prefix =>
|
|
Unchecked_Convert_To (Pref_Type,
|
|
Duplicate_Subexpr (Pref)),
|
|
Selector_Name => New_Occurrence_Of (Real_Discr, Loc));
|
|
|
|
-- Manually analyze and resolve this selected component. We really
|
|
-- want it just as it appears above, and do not want the expander
|
|
-- playing discriminal games etc with this reference. Then we append
|
|
-- the argument to the list we are gathering.
|
|
|
|
Set_Etype (Scomp, Etype (Real_Discr));
|
|
Set_Analyzed (Scomp, True);
|
|
Append_To (Args, Convert_To (Etype (Formal), Scomp));
|
|
|
|
Next_Formal_With_Extras (Formal);
|
|
Next_Discriminant (Discr);
|
|
end loop;
|
|
|
|
-- Now build and insert the call
|
|
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Function_Call (Loc,
|
|
Name => New_Occurrence_Of (Discr_Fct, Loc),
|
|
Parameter_Associations => Args),
|
|
Reason => CE_Discriminant_Check_Failed));
|
|
end Generate_Discriminant_Check;
|
|
|
|
---------------------------
|
|
-- Generate_Index_Checks --
|
|
---------------------------
|
|
|
|
procedure Generate_Index_Checks (N : Node_Id) is
|
|
|
|
function Entity_Of_Prefix return Entity_Id;
|
|
-- Returns the entity of the prefix of N (or Empty if not found)
|
|
|
|
----------------------
|
|
-- Entity_Of_Prefix --
|
|
----------------------
|
|
|
|
function Entity_Of_Prefix return Entity_Id is
|
|
P : Node_Id;
|
|
|
|
begin
|
|
P := Prefix (N);
|
|
while not Is_Entity_Name (P) loop
|
|
if not Nkind_In (P, N_Selected_Component,
|
|
N_Indexed_Component)
|
|
then
|
|
return Empty;
|
|
end if;
|
|
|
|
P := Prefix (P);
|
|
end loop;
|
|
|
|
return Entity (P);
|
|
end Entity_Of_Prefix;
|
|
|
|
-- Local variables
|
|
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
A : constant Node_Id := Prefix (N);
|
|
A_Ent : constant Entity_Id := Entity_Of_Prefix;
|
|
Sub : Node_Id;
|
|
|
|
-- Start of processing for Generate_Index_Checks
|
|
|
|
begin
|
|
-- Ignore call if the prefix is not an array since we have a serious
|
|
-- error in the sources. Ignore it also if index checks are suppressed
|
|
-- for array object or type.
|
|
|
|
if not Is_Array_Type (Etype (A))
|
|
or else (Present (A_Ent) and then Index_Checks_Suppressed (A_Ent))
|
|
or else Index_Checks_Suppressed (Etype (A))
|
|
then
|
|
return;
|
|
|
|
-- The indexed component we are dealing with contains 'Loop_Entry in its
|
|
-- prefix. This case arises when analysis has determined that constructs
|
|
-- such as
|
|
|
|
-- Prefix'Loop_Entry (Expr)
|
|
-- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN)
|
|
|
|
-- require rewriting for error detection purposes. A side effect of this
|
|
-- action is the generation of index checks that mention 'Loop_Entry.
|
|
-- Delay the generation of the check until 'Loop_Entry has been properly
|
|
-- expanded. This is done in Expand_Loop_Entry_Attributes.
|
|
|
|
elsif Nkind (Prefix (N)) = N_Attribute_Reference
|
|
and then Attribute_Name (Prefix (N)) = Name_Loop_Entry
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Generate a raise of constraint error with the appropriate reason and
|
|
-- a condition of the form:
|
|
|
|
-- Base_Type (Sub) not in Array'Range (Subscript)
|
|
|
|
-- Note that the reason we generate the conversion to the base type here
|
|
-- is that we definitely want the range check to take place, even if it
|
|
-- looks like the subtype is OK. Optimization considerations that allow
|
|
-- us to omit the check have already been taken into account in the
|
|
-- setting of the Do_Range_Check flag earlier on.
|
|
|
|
Sub := First (Expressions (N));
|
|
|
|
-- Handle string literals
|
|
|
|
if Ekind (Etype (A)) = E_String_Literal_Subtype then
|
|
if Do_Range_Check (Sub) then
|
|
Set_Do_Range_Check (Sub, False);
|
|
|
|
-- For string literals we obtain the bounds of the string from the
|
|
-- associated subtype.
|
|
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Not_In (Loc,
|
|
Left_Opnd =>
|
|
Convert_To (Base_Type (Etype (Sub)),
|
|
Duplicate_Subexpr_Move_Checks (Sub)),
|
|
Right_Opnd =>
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix => New_Occurrence_Of (Etype (A), Loc),
|
|
Attribute_Name => Name_Range)),
|
|
Reason => CE_Index_Check_Failed));
|
|
end if;
|
|
|
|
-- General case
|
|
|
|
else
|
|
declare
|
|
A_Idx : Node_Id := Empty;
|
|
A_Range : Node_Id;
|
|
Ind : Nat;
|
|
Num : List_Id;
|
|
Range_N : Node_Id;
|
|
|
|
begin
|
|
A_Idx := First_Index (Etype (A));
|
|
Ind := 1;
|
|
while Present (Sub) loop
|
|
if Do_Range_Check (Sub) then
|
|
Set_Do_Range_Check (Sub, False);
|
|
|
|
-- Force evaluation except for the case of a simple name of
|
|
-- a nonvolatile entity.
|
|
|
|
if not Is_Entity_Name (Sub)
|
|
or else Treat_As_Volatile (Entity (Sub))
|
|
then
|
|
Force_Evaluation (Sub);
|
|
end if;
|
|
|
|
if Nkind (A_Idx) = N_Range then
|
|
A_Range := A_Idx;
|
|
|
|
elsif Nkind (A_Idx) = N_Identifier
|
|
or else Nkind (A_Idx) = N_Expanded_Name
|
|
then
|
|
A_Range := Scalar_Range (Entity (A_Idx));
|
|
|
|
else pragma Assert (Nkind (A_Idx) = N_Subtype_Indication);
|
|
A_Range := Range_Expression (Constraint (A_Idx));
|
|
end if;
|
|
|
|
-- For array objects with constant bounds we can generate
|
|
-- the index check using the bounds of the type of the index
|
|
|
|
if Present (A_Ent)
|
|
and then Ekind (A_Ent) = E_Variable
|
|
and then Is_Constant_Bound (Low_Bound (A_Range))
|
|
and then Is_Constant_Bound (High_Bound (A_Range))
|
|
then
|
|
Range_N :=
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix =>
|
|
New_Occurrence_Of (Etype (A_Idx), Loc),
|
|
Attribute_Name => Name_Range);
|
|
|
|
-- For arrays with non-constant bounds we cannot generate
|
|
-- the index check using the bounds of the type of the index
|
|
-- since it may reference discriminants of some enclosing
|
|
-- type. We obtain the bounds directly from the prefix
|
|
-- object.
|
|
|
|
else
|
|
if Ind = 1 then
|
|
Num := No_List;
|
|
else
|
|
Num := New_List (Make_Integer_Literal (Loc, Ind));
|
|
end if;
|
|
|
|
Range_N :=
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix =>
|
|
Duplicate_Subexpr_Move_Checks (A, Name_Req => True),
|
|
Attribute_Name => Name_Range,
|
|
Expressions => Num);
|
|
end if;
|
|
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Not_In (Loc,
|
|
Left_Opnd =>
|
|
Convert_To (Base_Type (Etype (Sub)),
|
|
Duplicate_Subexpr_Move_Checks (Sub)),
|
|
Right_Opnd => Range_N),
|
|
Reason => CE_Index_Check_Failed));
|
|
end if;
|
|
|
|
A_Idx := Next_Index (A_Idx);
|
|
Ind := Ind + 1;
|
|
Next (Sub);
|
|
end loop;
|
|
end;
|
|
end if;
|
|
end Generate_Index_Checks;
|
|
|
|
--------------------------
|
|
-- Generate_Range_Check --
|
|
--------------------------
|
|
|
|
procedure Generate_Range_Check
|
|
(N : Node_Id;
|
|
Target_Type : Entity_Id;
|
|
Reason : RT_Exception_Code)
|
|
is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Source_Type : constant Entity_Id := Etype (N);
|
|
Source_Base_Type : constant Entity_Id := Base_Type (Source_Type);
|
|
Target_Base_Type : constant Entity_Id := Base_Type (Target_Type);
|
|
|
|
procedure Convert_And_Check_Range;
|
|
-- Convert the conversion operand to the target base type and save in
|
|
-- a temporary. Then check the converted value against the range of the
|
|
-- target subtype.
|
|
|
|
-----------------------------
|
|
-- Convert_And_Check_Range --
|
|
-----------------------------
|
|
|
|
procedure Convert_And_Check_Range is
|
|
Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N);
|
|
|
|
begin
|
|
-- We make a temporary to hold the value of the converted value
|
|
-- (converted to the base type), and then do the test against this
|
|
-- temporary. The conversion itself is replaced by an occurrence of
|
|
-- Tnn and followed by the explicit range check. Note that checks
|
|
-- are suppressed for this code, since we don't want a recursive
|
|
-- range check popping up.
|
|
|
|
-- Tnn : constant Target_Base_Type := Target_Base_Type (N);
|
|
-- [constraint_error when Tnn not in Target_Type]
|
|
|
|
Insert_Actions (N, New_List (
|
|
Make_Object_Declaration (Loc,
|
|
Defining_Identifier => Tnn,
|
|
Object_Definition => New_Occurrence_Of (Target_Base_Type, Loc),
|
|
Constant_Present => True,
|
|
Expression =>
|
|
Make_Type_Conversion (Loc,
|
|
Subtype_Mark => New_Occurrence_Of (Target_Base_Type, Loc),
|
|
Expression => Duplicate_Subexpr (N))),
|
|
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Not_In (Loc,
|
|
Left_Opnd => New_Occurrence_Of (Tnn, Loc),
|
|
Right_Opnd => New_Occurrence_Of (Target_Type, Loc)),
|
|
Reason => Reason)),
|
|
Suppress => All_Checks);
|
|
|
|
Rewrite (N, New_Occurrence_Of (Tnn, Loc));
|
|
|
|
-- Set the type of N, because the declaration for Tnn might not
|
|
-- be analyzed yet, as is the case if N appears within a record
|
|
-- declaration, as a discriminant constraint or expression.
|
|
|
|
Set_Etype (N, Target_Base_Type);
|
|
end Convert_And_Check_Range;
|
|
|
|
-- Start of processing for Generate_Range_Check
|
|
|
|
begin
|
|
-- First special case, if the source type is already within the range
|
|
-- of the target type, then no check is needed (probably we should have
|
|
-- stopped Do_Range_Check from being set in the first place, but better
|
|
-- late than never in preventing junk code and junk flag settings.
|
|
|
|
if In_Subrange_Of (Source_Type, Target_Type)
|
|
|
|
-- We do NOT apply this if the source node is a literal, since in this
|
|
-- case the literal has already been labeled as having the subtype of
|
|
-- the target.
|
|
|
|
and then not
|
|
(Nkind_In (N, N_Integer_Literal, N_Real_Literal, N_Character_Literal)
|
|
or else
|
|
(Is_Entity_Name (N)
|
|
and then Ekind (Entity (N)) = E_Enumeration_Literal))
|
|
then
|
|
Set_Do_Range_Check (N, False);
|
|
return;
|
|
end if;
|
|
|
|
-- Here a check is needed. If the expander is not active, or if we are
|
|
-- in GNATProve mode, then simply set the Do_Range_Check flag and we
|
|
-- are done. In both these cases, we just want to see the range check
|
|
-- flag set, we do not want to generate the explicit range check code.
|
|
|
|
if GNATprove_Mode or else not Expander_Active then
|
|
Set_Do_Range_Check (N, True);
|
|
return;
|
|
end if;
|
|
|
|
-- Here we will generate an explicit range check, so we don't want to
|
|
-- set the Do_Range check flag, since the range check is taken care of
|
|
-- by the code we will generate.
|
|
|
|
Set_Do_Range_Check (N, False);
|
|
|
|
-- Force evaluation of the node, so that it does not get evaluated twice
|
|
-- (once for the check, once for the actual reference). Such a double
|
|
-- evaluation is always a potential source of inefficiency, and is
|
|
-- functionally incorrect in the volatile case.
|
|
|
|
if not Is_Entity_Name (N) or else Treat_As_Volatile (Entity (N)) then
|
|
Force_Evaluation (N);
|
|
end if;
|
|
|
|
-- The easiest case is when Source_Base_Type and Target_Base_Type are
|
|
-- the same since in this case we can simply do a direct check of the
|
|
-- value of N against the bounds of Target_Type.
|
|
|
|
-- [constraint_error when N not in Target_Type]
|
|
|
|
-- Note: this is by far the most common case, for example all cases of
|
|
-- checks on the RHS of assignments are in this category, but not all
|
|
-- cases are like this. Notably conversions can involve two types.
|
|
|
|
if Source_Base_Type = Target_Base_Type then
|
|
|
|
-- Insert the explicit range check. Note that we suppress checks for
|
|
-- this code, since we don't want a recursive range check popping up.
|
|
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Not_In (Loc,
|
|
Left_Opnd => Duplicate_Subexpr (N),
|
|
Right_Opnd => New_Occurrence_Of (Target_Type, Loc)),
|
|
Reason => Reason),
|
|
Suppress => All_Checks);
|
|
|
|
-- Next test for the case where the target type is within the bounds
|
|
-- of the base type of the source type, since in this case we can
|
|
-- simply convert these bounds to the base type of T to do the test.
|
|
|
|
-- [constraint_error when N not in
|
|
-- Source_Base_Type (Target_Type'First)
|
|
-- ..
|
|
-- Source_Base_Type(Target_Type'Last))]
|
|
|
|
-- The conversions will always work and need no check
|
|
|
|
-- Unchecked_Convert_To is used instead of Convert_To to handle the case
|
|
-- of converting from an enumeration value to an integer type, such as
|
|
-- occurs for the case of generating a range check on Enum'Val(Exp)
|
|
-- (which used to be handled by gigi). This is OK, since the conversion
|
|
-- itself does not require a check.
|
|
|
|
elsif In_Subrange_Of (Target_Type, Source_Base_Type) then
|
|
|
|
-- Insert the explicit range check. Note that we suppress checks for
|
|
-- this code, since we don't want a recursive range check popping up.
|
|
|
|
if Is_Discrete_Type (Source_Base_Type)
|
|
and then
|
|
Is_Discrete_Type (Target_Base_Type)
|
|
then
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Not_In (Loc,
|
|
Left_Opnd => Duplicate_Subexpr (N),
|
|
|
|
Right_Opnd =>
|
|
Make_Range (Loc,
|
|
Low_Bound =>
|
|
Unchecked_Convert_To (Source_Base_Type,
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix =>
|
|
New_Occurrence_Of (Target_Type, Loc),
|
|
Attribute_Name => Name_First)),
|
|
|
|
High_Bound =>
|
|
Unchecked_Convert_To (Source_Base_Type,
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix =>
|
|
New_Occurrence_Of (Target_Type, Loc),
|
|
Attribute_Name => Name_Last)))),
|
|
Reason => Reason),
|
|
Suppress => All_Checks);
|
|
|
|
-- For conversions involving at least one type that is not discrete,
|
|
-- first convert to target type and then generate the range check.
|
|
-- This avoids problems with values that are close to a bound of the
|
|
-- target type that would fail a range check when done in a larger
|
|
-- source type before converting but would pass if converted with
|
|
-- rounding and then checked (such as in float-to-float conversions).
|
|
|
|
else
|
|
Convert_And_Check_Range;
|
|
end if;
|
|
|
|
-- Note that at this stage we now that the Target_Base_Type is not in
|
|
-- the range of the Source_Base_Type (since even the Target_Type itself
|
|
-- is not in this range). It could still be the case that Source_Type is
|
|
-- in range of the target base type since we have not checked that case.
|
|
|
|
-- If that is the case, we can freely convert the source to the target,
|
|
-- and then test the target result against the bounds.
|
|
|
|
elsif In_Subrange_Of (Source_Type, Target_Base_Type) then
|
|
Convert_And_Check_Range;
|
|
|
|
-- At this stage, we know that we have two scalar types, which are
|
|
-- directly convertible, and where neither scalar type has a base
|
|
-- range that is in the range of the other scalar type.
|
|
|
|
-- The only way this can happen is with a signed and unsigned type.
|
|
-- So test for these two cases:
|
|
|
|
else
|
|
-- Case of the source is unsigned and the target is signed
|
|
|
|
if Is_Unsigned_Type (Source_Base_Type)
|
|
and then not Is_Unsigned_Type (Target_Base_Type)
|
|
then
|
|
-- If the source is unsigned and the target is signed, then we
|
|
-- know that the source is not shorter than the target (otherwise
|
|
-- the source base type would be in the target base type range).
|
|
|
|
-- In other words, the unsigned type is either the same size as
|
|
-- the target, or it is larger. It cannot be smaller.
|
|
|
|
pragma Assert
|
|
(Esize (Source_Base_Type) >= Esize (Target_Base_Type));
|
|
|
|
-- We only need to check the low bound if the low bound of the
|
|
-- target type is non-negative. If the low bound of the target
|
|
-- type is negative, then we know that we will fit fine.
|
|
|
|
-- If the high bound of the target type is negative, then we
|
|
-- know we have a constraint error, since we can't possibly
|
|
-- have a negative source.
|
|
|
|
-- With these two checks out of the way, we can do the check
|
|
-- using the source type safely
|
|
|
|
-- This is definitely the most annoying case.
|
|
|
|
-- [constraint_error
|
|
-- when (Target_Type'First >= 0
|
|
-- and then
|
|
-- N < Source_Base_Type (Target_Type'First))
|
|
-- or else Target_Type'Last < 0
|
|
-- or else N > Source_Base_Type (Target_Type'Last)];
|
|
|
|
-- We turn off all checks since we know that the conversions
|
|
-- will work fine, given the guards for negative values.
|
|
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Or_Else (Loc,
|
|
Make_Or_Else (Loc,
|
|
Left_Opnd =>
|
|
Make_And_Then (Loc,
|
|
Left_Opnd => Make_Op_Ge (Loc,
|
|
Left_Opnd =>
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix =>
|
|
New_Occurrence_Of (Target_Type, Loc),
|
|
Attribute_Name => Name_First),
|
|
Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
|
|
|
|
Right_Opnd =>
|
|
Make_Op_Lt (Loc,
|
|
Left_Opnd => Duplicate_Subexpr (N),
|
|
Right_Opnd =>
|
|
Convert_To (Source_Base_Type,
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix =>
|
|
New_Occurrence_Of (Target_Type, Loc),
|
|
Attribute_Name => Name_First)))),
|
|
|
|
Right_Opnd =>
|
|
Make_Op_Lt (Loc,
|
|
Left_Opnd =>
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix => New_Occurrence_Of (Target_Type, Loc),
|
|
Attribute_Name => Name_Last),
|
|
Right_Opnd => Make_Integer_Literal (Loc, Uint_0))),
|
|
|
|
Right_Opnd =>
|
|
Make_Op_Gt (Loc,
|
|
Left_Opnd => Duplicate_Subexpr (N),
|
|
Right_Opnd =>
|
|
Convert_To (Source_Base_Type,
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix => New_Occurrence_Of (Target_Type, Loc),
|
|
Attribute_Name => Name_Last)))),
|
|
|
|
Reason => Reason),
|
|
Suppress => All_Checks);
|
|
|
|
-- Only remaining possibility is that the source is signed and
|
|
-- the target is unsigned.
|
|
|
|
else
|
|
pragma Assert (not Is_Unsigned_Type (Source_Base_Type)
|
|
and then Is_Unsigned_Type (Target_Base_Type));
|
|
|
|
-- If the source is signed and the target is unsigned, then we
|
|
-- know that the target is not shorter than the source (otherwise
|
|
-- the target base type would be in the source base type range).
|
|
|
|
-- In other words, the unsigned type is either the same size as
|
|
-- the target, or it is larger. It cannot be smaller.
|
|
|
|
-- Clearly we have an error if the source value is negative since
|
|
-- no unsigned type can have negative values. If the source type
|
|
-- is non-negative, then the check can be done using the target
|
|
-- type.
|
|
|
|
-- Tnn : constant Target_Base_Type (N) := Target_Type;
|
|
|
|
-- [constraint_error
|
|
-- when N < 0 or else Tnn not in Target_Type];
|
|
|
|
-- We turn off all checks for the conversion of N to the target
|
|
-- base type, since we generate the explicit check to ensure that
|
|
-- the value is non-negative
|
|
|
|
declare
|
|
Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', N);
|
|
|
|
begin
|
|
Insert_Actions (N, New_List (
|
|
Make_Object_Declaration (Loc,
|
|
Defining_Identifier => Tnn,
|
|
Object_Definition =>
|
|
New_Occurrence_Of (Target_Base_Type, Loc),
|
|
Constant_Present => True,
|
|
Expression =>
|
|
Make_Unchecked_Type_Conversion (Loc,
|
|
Subtype_Mark =>
|
|
New_Occurrence_Of (Target_Base_Type, Loc),
|
|
Expression => Duplicate_Subexpr (N))),
|
|
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Or_Else (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Lt (Loc,
|
|
Left_Opnd => Duplicate_Subexpr (N),
|
|
Right_Opnd => Make_Integer_Literal (Loc, Uint_0)),
|
|
|
|
Right_Opnd =>
|
|
Make_Not_In (Loc,
|
|
Left_Opnd => New_Occurrence_Of (Tnn, Loc),
|
|
Right_Opnd =>
|
|
New_Occurrence_Of (Target_Type, Loc))),
|
|
|
|
Reason => Reason)),
|
|
Suppress => All_Checks);
|
|
|
|
-- Set the Etype explicitly, because Insert_Actions may have
|
|
-- placed the declaration in the freeze list for an enclosing
|
|
-- construct, and thus it is not analyzed yet.
|
|
|
|
Set_Etype (Tnn, Target_Base_Type);
|
|
Rewrite (N, New_Occurrence_Of (Tnn, Loc));
|
|
end;
|
|
end if;
|
|
end if;
|
|
end Generate_Range_Check;
|
|
|
|
------------------
|
|
-- Get_Check_Id --
|
|
------------------
|
|
|
|
function Get_Check_Id (N : Name_Id) return Check_Id is
|
|
begin
|
|
-- For standard check name, we can do a direct computation
|
|
|
|
if N in First_Check_Name .. Last_Check_Name then
|
|
return Check_Id (N - (First_Check_Name - 1));
|
|
|
|
-- For non-standard names added by pragma Check_Name, search table
|
|
|
|
else
|
|
for J in All_Checks + 1 .. Check_Names.Last loop
|
|
if Check_Names.Table (J) = N then
|
|
return J;
|
|
end if;
|
|
end loop;
|
|
end if;
|
|
|
|
-- No matching name found
|
|
|
|
return No_Check_Id;
|
|
end Get_Check_Id;
|
|
|
|
---------------------
|
|
-- Get_Discriminal --
|
|
---------------------
|
|
|
|
function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is
|
|
Loc : constant Source_Ptr := Sloc (E);
|
|
D : Entity_Id;
|
|
Sc : Entity_Id;
|
|
|
|
begin
|
|
-- The bound can be a bona fide parameter of a protected operation,
|
|
-- rather than a prival encoded as an in-parameter.
|
|
|
|
if No (Discriminal_Link (Entity (Bound))) then
|
|
return Bound;
|
|
end if;
|
|
|
|
-- Climb the scope stack looking for an enclosing protected type. If
|
|
-- we run out of scopes, return the bound itself.
|
|
|
|
Sc := Scope (E);
|
|
while Present (Sc) loop
|
|
if Sc = Standard_Standard then
|
|
return Bound;
|
|
elsif Ekind (Sc) = E_Protected_Type then
|
|
exit;
|
|
end if;
|
|
|
|
Sc := Scope (Sc);
|
|
end loop;
|
|
|
|
D := First_Discriminant (Sc);
|
|
while Present (D) loop
|
|
if Chars (D) = Chars (Bound) then
|
|
return New_Occurrence_Of (Discriminal (D), Loc);
|
|
end if;
|
|
|
|
Next_Discriminant (D);
|
|
end loop;
|
|
|
|
return Bound;
|
|
end Get_Discriminal;
|
|
|
|
----------------------
|
|
-- Get_Range_Checks --
|
|
----------------------
|
|
|
|
function Get_Range_Checks
|
|
(Ck_Node : Node_Id;
|
|
Target_Typ : Entity_Id;
|
|
Source_Typ : Entity_Id := Empty;
|
|
Warn_Node : Node_Id := Empty) return Check_Result
|
|
is
|
|
begin
|
|
return
|
|
Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Warn_Node);
|
|
end Get_Range_Checks;
|
|
|
|
------------------
|
|
-- Guard_Access --
|
|
------------------
|
|
|
|
function Guard_Access
|
|
(Cond : Node_Id;
|
|
Loc : Source_Ptr;
|
|
Ck_Node : Node_Id) return Node_Id
|
|
is
|
|
begin
|
|
if Nkind (Cond) = N_Or_Else then
|
|
Set_Paren_Count (Cond, 1);
|
|
end if;
|
|
|
|
if Nkind (Ck_Node) = N_Allocator then
|
|
return Cond;
|
|
|
|
else
|
|
return
|
|
Make_And_Then (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Ne (Loc,
|
|
Left_Opnd => Duplicate_Subexpr_No_Checks (Ck_Node),
|
|
Right_Opnd => Make_Null (Loc)),
|
|
Right_Opnd => Cond);
|
|
end if;
|
|
end Guard_Access;
|
|
|
|
-----------------------------
|
|
-- Index_Checks_Suppressed --
|
|
-----------------------------
|
|
|
|
function Index_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) and then Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Index_Check);
|
|
else
|
|
return Scope_Suppress.Suppress (Index_Check);
|
|
end if;
|
|
end Index_Checks_Suppressed;
|
|
|
|
----------------
|
|
-- Initialize --
|
|
----------------
|
|
|
|
procedure Initialize is
|
|
begin
|
|
for J in Determine_Range_Cache_N'Range loop
|
|
Determine_Range_Cache_N (J) := Empty;
|
|
end loop;
|
|
|
|
Check_Names.Init;
|
|
|
|
for J in Int range 1 .. All_Checks loop
|
|
Check_Names.Append (Name_Id (Int (First_Check_Name) + J - 1));
|
|
end loop;
|
|
end Initialize;
|
|
|
|
-------------------------
|
|
-- Insert_Range_Checks --
|
|
-------------------------
|
|
|
|
procedure Insert_Range_Checks
|
|
(Checks : Check_Result;
|
|
Node : Node_Id;
|
|
Suppress_Typ : Entity_Id;
|
|
Static_Sloc : Source_Ptr := No_Location;
|
|
Flag_Node : Node_Id := Empty;
|
|
Do_Before : Boolean := False)
|
|
is
|
|
Internal_Flag_Node : Node_Id := Flag_Node;
|
|
Internal_Static_Sloc : Source_Ptr := Static_Sloc;
|
|
|
|
Check_Node : Node_Id;
|
|
Checks_On : constant Boolean :=
|
|
(not Index_Checks_Suppressed (Suppress_Typ))
|
|
or else (not Range_Checks_Suppressed (Suppress_Typ));
|
|
|
|
begin
|
|
-- For now we just return if Checks_On is false, however this should be
|
|
-- enhanced to check for an always True value in the condition and to
|
|
-- generate a compilation warning???
|
|
|
|
if not Expander_Active or not Checks_On then
|
|
return;
|
|
end if;
|
|
|
|
if Static_Sloc = No_Location then
|
|
Internal_Static_Sloc := Sloc (Node);
|
|
end if;
|
|
|
|
if No (Flag_Node) then
|
|
Internal_Flag_Node := Node;
|
|
end if;
|
|
|
|
for J in 1 .. 2 loop
|
|
exit when No (Checks (J));
|
|
|
|
if Nkind (Checks (J)) = N_Raise_Constraint_Error
|
|
and then Present (Condition (Checks (J)))
|
|
then
|
|
if not Has_Dynamic_Range_Check (Internal_Flag_Node) then
|
|
Check_Node := Checks (J);
|
|
Mark_Rewrite_Insertion (Check_Node);
|
|
|
|
if Do_Before then
|
|
Insert_Before_And_Analyze (Node, Check_Node);
|
|
else
|
|
Insert_After_And_Analyze (Node, Check_Node);
|
|
end if;
|
|
|
|
Set_Has_Dynamic_Range_Check (Internal_Flag_Node);
|
|
end if;
|
|
|
|
else
|
|
Check_Node :=
|
|
Make_Raise_Constraint_Error (Internal_Static_Sloc,
|
|
Reason => CE_Range_Check_Failed);
|
|
Mark_Rewrite_Insertion (Check_Node);
|
|
|
|
if Do_Before then
|
|
Insert_Before_And_Analyze (Node, Check_Node);
|
|
else
|
|
Insert_After_And_Analyze (Node, Check_Node);
|
|
end if;
|
|
end if;
|
|
end loop;
|
|
end Insert_Range_Checks;
|
|
|
|
------------------------
|
|
-- Insert_Valid_Check --
|
|
------------------------
|
|
|
|
procedure Insert_Valid_Check
|
|
(Expr : Node_Id;
|
|
Related_Id : Entity_Id := Empty;
|
|
Is_Low_Bound : Boolean := False;
|
|
Is_High_Bound : Boolean := False)
|
|
is
|
|
Loc : constant Source_Ptr := Sloc (Expr);
|
|
Typ : constant Entity_Id := Etype (Expr);
|
|
Exp : Node_Id;
|
|
|
|
begin
|
|
-- Do not insert if checks off, or if not checking validity or if
|
|
-- expression is known to be valid.
|
|
|
|
if not Validity_Checks_On
|
|
or else Range_Or_Validity_Checks_Suppressed (Expr)
|
|
or else Expr_Known_Valid (Expr)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Do not insert checks within a predicate function. This will arise
|
|
-- if the current unit and the predicate function are being compiled
|
|
-- with validity checks enabled.
|
|
|
|
if Present (Predicate_Function (Typ))
|
|
and then Current_Scope = Predicate_Function (Typ)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- If the expression is a packed component of a modular type of the
|
|
-- right size, the data is always valid.
|
|
|
|
if Nkind (Expr) = N_Selected_Component
|
|
and then Present (Component_Clause (Entity (Selector_Name (Expr))))
|
|
and then Is_Modular_Integer_Type (Typ)
|
|
and then Modulus (Typ) = 2 ** Esize (Entity (Selector_Name (Expr)))
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- If we have a checked conversion, then validity check applies to
|
|
-- the expression inside the conversion, not the result, since if
|
|
-- the expression inside is valid, then so is the conversion result.
|
|
|
|
Exp := Expr;
|
|
while Nkind (Exp) = N_Type_Conversion loop
|
|
Exp := Expression (Exp);
|
|
end loop;
|
|
|
|
-- We are about to insert the validity check for Exp. We save and
|
|
-- reset the Do_Range_Check flag over this validity check, and then
|
|
-- put it back for the final original reference (Exp may be rewritten).
|
|
|
|
declare
|
|
DRC : constant Boolean := Do_Range_Check (Exp);
|
|
PV : Node_Id;
|
|
CE : Node_Id;
|
|
|
|
begin
|
|
Set_Do_Range_Check (Exp, False);
|
|
|
|
-- Force evaluation to avoid multiple reads for atomic/volatile
|
|
|
|
-- Note: we set Name_Req to False. We used to set it to True, with
|
|
-- the thinking that a name is required as the prefix of the 'Valid
|
|
-- call, but in fact the check that the prefix of an attribute is
|
|
-- a name is in the parser, and we just don't require it here.
|
|
-- Moreover, when we set Name_Req to True, that interfered with the
|
|
-- checking for Volatile, since we couldn't just capture the value.
|
|
|
|
if Is_Entity_Name (Exp)
|
|
and then Is_Volatile (Entity (Exp))
|
|
then
|
|
-- Same reasoning as above for setting Name_Req to False
|
|
|
|
Force_Evaluation (Exp, Name_Req => False);
|
|
end if;
|
|
|
|
-- Build the prefix for the 'Valid call
|
|
|
|
PV :=
|
|
Duplicate_Subexpr_No_Checks
|
|
(Exp => Exp,
|
|
Name_Req => False,
|
|
Related_Id => Related_Id,
|
|
Is_Low_Bound => Is_Low_Bound,
|
|
Is_High_Bound => Is_High_Bound);
|
|
|
|
-- A rather specialized test. If PV is an analyzed expression which
|
|
-- is an indexed component of a packed array that has not been
|
|
-- properly expanded, turn off its Analyzed flag to make sure it
|
|
-- gets properly reexpanded. If the prefix is an access value,
|
|
-- the dereference will be added later.
|
|
|
|
-- The reason this arises is that Duplicate_Subexpr_No_Checks did
|
|
-- an analyze with the old parent pointer. This may point e.g. to
|
|
-- a subprogram call, which deactivates this expansion.
|
|
|
|
if Analyzed (PV)
|
|
and then Nkind (PV) = N_Indexed_Component
|
|
and then Is_Array_Type (Etype (Prefix (PV)))
|
|
and then Present (Packed_Array_Impl_Type (Etype (Prefix (PV))))
|
|
then
|
|
Set_Analyzed (PV, False);
|
|
end if;
|
|
|
|
-- Build the raise CE node to check for validity. We build a type
|
|
-- qualification for the prefix, since it may not be of the form of
|
|
-- a name, and we don't care in this context!
|
|
|
|
CE :=
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Op_Not (Loc,
|
|
Right_Opnd =>
|
|
Make_Attribute_Reference (Loc,
|
|
Prefix => PV,
|
|
Attribute_Name => Name_Valid)),
|
|
Reason => CE_Invalid_Data);
|
|
|
|
-- Insert the validity check. Note that we do this with validity
|
|
-- checks turned off, to avoid recursion, we do not want validity
|
|
-- checks on the validity checking code itself.
|
|
|
|
Insert_Action (Expr, CE, Suppress => Validity_Check);
|
|
|
|
-- If the expression is a reference to an element of a bit-packed
|
|
-- array, then it is rewritten as a renaming declaration. If the
|
|
-- expression is an actual in a call, it has not been expanded,
|
|
-- waiting for the proper point at which to do it. The same happens
|
|
-- with renamings, so that we have to force the expansion now. This
|
|
-- non-local complication is due to code in exp_ch2,adb, exp_ch4.adb
|
|
-- and exp_ch6.adb.
|
|
|
|
if Is_Entity_Name (Exp)
|
|
and then Nkind (Parent (Entity (Exp))) =
|
|
N_Object_Renaming_Declaration
|
|
then
|
|
declare
|
|
Old_Exp : constant Node_Id := Name (Parent (Entity (Exp)));
|
|
begin
|
|
if Nkind (Old_Exp) = N_Indexed_Component
|
|
and then Is_Bit_Packed_Array (Etype (Prefix (Old_Exp)))
|
|
then
|
|
Expand_Packed_Element_Reference (Old_Exp);
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
-- Put back the Do_Range_Check flag on the resulting (possibly
|
|
-- rewritten) expression.
|
|
|
|
-- Note: it might be thought that a validity check is not required
|
|
-- when a range check is present, but that's not the case, because
|
|
-- the back end is allowed to assume for the range check that the
|
|
-- operand is within its declared range (an assumption that validity
|
|
-- checking is all about NOT assuming).
|
|
|
|
-- Note: no need to worry about Possible_Local_Raise here, it will
|
|
-- already have been called if original node has Do_Range_Check set.
|
|
|
|
Set_Do_Range_Check (Exp, DRC);
|
|
end;
|
|
end Insert_Valid_Check;
|
|
|
|
-------------------------------------
|
|
-- Is_Signed_Integer_Arithmetic_Op --
|
|
-------------------------------------
|
|
|
|
function Is_Signed_Integer_Arithmetic_Op (N : Node_Id) return Boolean is
|
|
begin
|
|
case Nkind (N) is
|
|
when N_Op_Abs | N_Op_Add | N_Op_Divide | N_Op_Expon |
|
|
N_Op_Minus | N_Op_Mod | N_Op_Multiply | N_Op_Plus |
|
|
N_Op_Rem | N_Op_Subtract =>
|
|
return Is_Signed_Integer_Type (Etype (N));
|
|
|
|
when N_If_Expression | N_Case_Expression =>
|
|
return Is_Signed_Integer_Type (Etype (N));
|
|
|
|
when others =>
|
|
return False;
|
|
end case;
|
|
end Is_Signed_Integer_Arithmetic_Op;
|
|
|
|
----------------------------------
|
|
-- Install_Null_Excluding_Check --
|
|
----------------------------------
|
|
|
|
procedure Install_Null_Excluding_Check (N : Node_Id) is
|
|
Loc : constant Source_Ptr := Sloc (Parent (N));
|
|
Typ : constant Entity_Id := Etype (N);
|
|
|
|
function Safe_To_Capture_In_Parameter_Value return Boolean;
|
|
-- Determines if it is safe to capture Known_Non_Null status for an
|
|
-- the entity referenced by node N. The caller ensures that N is indeed
|
|
-- an entity name. It is safe to capture the non-null status for an IN
|
|
-- parameter when the reference occurs within a declaration that is sure
|
|
-- to be executed as part of the declarative region.
|
|
|
|
procedure Mark_Non_Null;
|
|
-- After installation of check, if the node in question is an entity
|
|
-- name, then mark this entity as non-null if possible.
|
|
|
|
function Safe_To_Capture_In_Parameter_Value return Boolean is
|
|
E : constant Entity_Id := Entity (N);
|
|
S : constant Entity_Id := Current_Scope;
|
|
S_Par : Node_Id;
|
|
|
|
begin
|
|
if Ekind (E) /= E_In_Parameter then
|
|
return False;
|
|
end if;
|
|
|
|
-- Two initial context checks. We must be inside a subprogram body
|
|
-- with declarations and reference must not appear in nested scopes.
|
|
|
|
if (Ekind (S) /= E_Function and then Ekind (S) /= E_Procedure)
|
|
or else Scope (E) /= S
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
S_Par := Parent (Parent (S));
|
|
|
|
if Nkind (S_Par) /= N_Subprogram_Body
|
|
or else No (Declarations (S_Par))
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
declare
|
|
N_Decl : Node_Id;
|
|
P : Node_Id;
|
|
|
|
begin
|
|
-- Retrieve the declaration node of N (if any). Note that N
|
|
-- may be a part of a complex initialization expression.
|
|
|
|
P := Parent (N);
|
|
N_Decl := Empty;
|
|
while Present (P) loop
|
|
|
|
-- If we have a short circuit form, and we are within the right
|
|
-- hand expression, we return false, since the right hand side
|
|
-- is not guaranteed to be elaborated.
|
|
|
|
if Nkind (P) in N_Short_Circuit
|
|
and then N = Right_Opnd (P)
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
-- Similarly, if we are in an if expression and not part of the
|
|
-- condition, then we return False, since neither the THEN or
|
|
-- ELSE dependent expressions will always be elaborated.
|
|
|
|
if Nkind (P) = N_If_Expression
|
|
and then N /= First (Expressions (P))
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
-- If within a case expression, and not part of the expression,
|
|
-- then return False, since a particular dependent expression
|
|
-- may not always be elaborated
|
|
|
|
if Nkind (P) = N_Case_Expression
|
|
and then N /= Expression (P)
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
-- While traversing the parent chain, if node N belongs to a
|
|
-- statement, then it may never appear in a declarative region.
|
|
|
|
if Nkind (P) in N_Statement_Other_Than_Procedure_Call
|
|
or else Nkind (P) = N_Procedure_Call_Statement
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
-- If we are at a declaration, record it and exit
|
|
|
|
if Nkind (P) in N_Declaration
|
|
and then Nkind (P) not in N_Subprogram_Specification
|
|
then
|
|
N_Decl := P;
|
|
exit;
|
|
end if;
|
|
|
|
P := Parent (P);
|
|
end loop;
|
|
|
|
if No (N_Decl) then
|
|
return False;
|
|
end if;
|
|
|
|
return List_Containing (N_Decl) = Declarations (S_Par);
|
|
end;
|
|
end Safe_To_Capture_In_Parameter_Value;
|
|
|
|
-------------------
|
|
-- Mark_Non_Null --
|
|
-------------------
|
|
|
|
procedure Mark_Non_Null is
|
|
begin
|
|
-- Only case of interest is if node N is an entity name
|
|
|
|
if Is_Entity_Name (N) then
|
|
|
|
-- For sure, we want to clear an indication that this is known to
|
|
-- be null, since if we get past this check, it definitely is not.
|
|
|
|
Set_Is_Known_Null (Entity (N), False);
|
|
|
|
-- We can mark the entity as known to be non-null if either it is
|
|
-- safe to capture the value, or in the case of an IN parameter,
|
|
-- which is a constant, if the check we just installed is in the
|
|
-- declarative region of the subprogram body. In this latter case,
|
|
-- a check is decisive for the rest of the body if the expression
|
|
-- is sure to be elaborated, since we know we have to elaborate
|
|
-- all declarations before executing the body.
|
|
|
|
-- Couldn't this always be part of Safe_To_Capture_Value ???
|
|
|
|
if Safe_To_Capture_Value (N, Entity (N))
|
|
or else Safe_To_Capture_In_Parameter_Value
|
|
then
|
|
Set_Is_Known_Non_Null (Entity (N));
|
|
end if;
|
|
end if;
|
|
end Mark_Non_Null;
|
|
|
|
-- Start of processing for Install_Null_Excluding_Check
|
|
|
|
begin
|
|
pragma Assert (Is_Access_Type (Typ));
|
|
|
|
-- No check inside a generic, check will be emitted in instance
|
|
|
|
if Inside_A_Generic then
|
|
return;
|
|
end if;
|
|
|
|
-- No check needed if known to be non-null
|
|
|
|
if Known_Non_Null (N) then
|
|
return;
|
|
end if;
|
|
|
|
-- If known to be null, here is where we generate a compile time check
|
|
|
|
if Known_Null (N) then
|
|
|
|
-- Avoid generating warning message inside init procs. In SPARK mode
|
|
-- we can go ahead and call Apply_Compile_Time_Constraint_Error
|
|
-- since it will be turned into an error in any case.
|
|
|
|
if (not Inside_Init_Proc or else SPARK_Mode = On)
|
|
|
|
-- Do not emit the warning within a conditional expression,
|
|
-- where the expression might not be evaluated, and the warning
|
|
-- appear as extraneous noise.
|
|
|
|
and then not Within_Case_Or_If_Expression (N)
|
|
then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "null value not allowed here??", CE_Access_Check_Failed);
|
|
|
|
-- Remaining cases, where we silently insert the raise
|
|
|
|
else
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Reason => CE_Access_Check_Failed));
|
|
end if;
|
|
|
|
Mark_Non_Null;
|
|
return;
|
|
end if;
|
|
|
|
-- If entity is never assigned, for sure a warning is appropriate
|
|
|
|
if Is_Entity_Name (N) then
|
|
Check_Unset_Reference (N);
|
|
end if;
|
|
|
|
-- No check needed if checks are suppressed on the range. Note that we
|
|
-- don't set Is_Known_Non_Null in this case (we could legitimately do
|
|
-- so, since the program is erroneous, but we don't like to casually
|
|
-- propagate such conclusions from erroneosity).
|
|
|
|
if Access_Checks_Suppressed (Typ) then
|
|
return;
|
|
end if;
|
|
|
|
-- No check needed for access to concurrent record types generated by
|
|
-- the expander. This is not just an optimization (though it does indeed
|
|
-- remove junk checks). It also avoids generation of junk warnings.
|
|
|
|
if Nkind (N) in N_Has_Chars
|
|
and then Chars (N) = Name_uObject
|
|
and then Is_Concurrent_Record_Type
|
|
(Directly_Designated_Type (Etype (N)))
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- No check needed in interface thunks since the runtime check is
|
|
-- already performed at the caller side.
|
|
|
|
if Is_Thunk (Current_Scope) then
|
|
return;
|
|
end if;
|
|
|
|
-- No check needed for the Get_Current_Excep.all.all idiom generated by
|
|
-- the expander within exception handlers, since we know that the value
|
|
-- can never be null.
|
|
|
|
-- Is this really the right way to do this? Normally we generate such
|
|
-- code in the expander with checks off, and that's how we suppress this
|
|
-- kind of junk check ???
|
|
|
|
if Nkind (N) = N_Function_Call
|
|
and then Nkind (Name (N)) = N_Explicit_Dereference
|
|
and then Nkind (Prefix (Name (N))) = N_Identifier
|
|
and then Is_RTE (Entity (Prefix (Name (N))), RE_Get_Current_Excep)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise install access check
|
|
|
|
Insert_Action (N,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Condition =>
|
|
Make_Op_Eq (Loc,
|
|
Left_Opnd => Duplicate_Subexpr_Move_Checks (N),
|
|
Right_Opnd => Make_Null (Loc)),
|
|
Reason => CE_Access_Check_Failed));
|
|
|
|
Mark_Non_Null;
|
|
end Install_Null_Excluding_Check;
|
|
|
|
--------------------------
|
|
-- Install_Static_Check --
|
|
--------------------------
|
|
|
|
procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is
|
|
Stat : constant Boolean := Is_OK_Static_Expression (R_Cno);
|
|
Typ : constant Entity_Id := Etype (R_Cno);
|
|
|
|
begin
|
|
Rewrite (R_Cno,
|
|
Make_Raise_Constraint_Error (Loc,
|
|
Reason => CE_Range_Check_Failed));
|
|
Set_Analyzed (R_Cno);
|
|
Set_Etype (R_Cno, Typ);
|
|
Set_Raises_Constraint_Error (R_Cno);
|
|
Set_Is_Static_Expression (R_Cno, Stat);
|
|
|
|
-- Now deal with possible local raise handling
|
|
|
|
Possible_Local_Raise (R_Cno, Standard_Constraint_Error);
|
|
end Install_Static_Check;
|
|
|
|
-------------------------
|
|
-- Is_Check_Suppressed --
|
|
-------------------------
|
|
|
|
function Is_Check_Suppressed (E : Entity_Id; C : Check_Id) return Boolean is
|
|
Ptr : Suppress_Stack_Entry_Ptr;
|
|
|
|
begin
|
|
-- First search the local entity suppress stack. We search this from the
|
|
-- top of the stack down so that we get the innermost entry that applies
|
|
-- to this case if there are nested entries.
|
|
|
|
Ptr := Local_Suppress_Stack_Top;
|
|
while Ptr /= null loop
|
|
if (Ptr.Entity = Empty or else Ptr.Entity = E)
|
|
and then (Ptr.Check = All_Checks or else Ptr.Check = C)
|
|
then
|
|
return Ptr.Suppress;
|
|
end if;
|
|
|
|
Ptr := Ptr.Prev;
|
|
end loop;
|
|
|
|
-- Now search the global entity suppress table for a matching entry.
|
|
-- We also search this from the top down so that if there are multiple
|
|
-- pragmas for the same entity, the last one applies (not clear what
|
|
-- or whether the RM specifies this handling, but it seems reasonable).
|
|
|
|
Ptr := Global_Suppress_Stack_Top;
|
|
while Ptr /= null loop
|
|
if (Ptr.Entity = Empty or else Ptr.Entity = E)
|
|
and then (Ptr.Check = All_Checks or else Ptr.Check = C)
|
|
then
|
|
return Ptr.Suppress;
|
|
end if;
|
|
|
|
Ptr := Ptr.Prev;
|
|
end loop;
|
|
|
|
-- If we did not find a matching entry, then use the normal scope
|
|
-- suppress value after all (actually this will be the global setting
|
|
-- since it clearly was not overridden at any point). For a predefined
|
|
-- check, we test the specific flag. For a user defined check, we check
|
|
-- the All_Checks flag. The Overflow flag requires special handling to
|
|
-- deal with the General vs Assertion case
|
|
|
|
if C = Overflow_Check then
|
|
return Overflow_Checks_Suppressed (Empty);
|
|
elsif C in Predefined_Check_Id then
|
|
return Scope_Suppress.Suppress (C);
|
|
else
|
|
return Scope_Suppress.Suppress (All_Checks);
|
|
end if;
|
|
end Is_Check_Suppressed;
|
|
|
|
---------------------
|
|
-- Kill_All_Checks --
|
|
---------------------
|
|
|
|
procedure Kill_All_Checks is
|
|
begin
|
|
if Debug_Flag_CC then
|
|
w ("Kill_All_Checks");
|
|
end if;
|
|
|
|
-- We reset the number of saved checks to zero, and also modify all
|
|
-- stack entries for statement ranges to indicate that the number of
|
|
-- checks at each level is now zero.
|
|
|
|
Num_Saved_Checks := 0;
|
|
|
|
-- Note: the Int'Min here avoids any possibility of J being out of
|
|
-- range when called from e.g. Conditional_Statements_Begin.
|
|
|
|
for J in 1 .. Int'Min (Saved_Checks_TOS, Saved_Checks_Stack'Last) loop
|
|
Saved_Checks_Stack (J) := 0;
|
|
end loop;
|
|
end Kill_All_Checks;
|
|
|
|
-----------------
|
|
-- Kill_Checks --
|
|
-----------------
|
|
|
|
procedure Kill_Checks (V : Entity_Id) is
|
|
begin
|
|
if Debug_Flag_CC then
|
|
w ("Kill_Checks for entity", Int (V));
|
|
end if;
|
|
|
|
for J in 1 .. Num_Saved_Checks loop
|
|
if Saved_Checks (J).Entity = V then
|
|
if Debug_Flag_CC then
|
|
w (" Checks killed for saved check ", J);
|
|
end if;
|
|
|
|
Saved_Checks (J).Killed := True;
|
|
end if;
|
|
end loop;
|
|
end Kill_Checks;
|
|
|
|
------------------------------
|
|
-- Length_Checks_Suppressed --
|
|
------------------------------
|
|
|
|
function Length_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) and then Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Length_Check);
|
|
else
|
|
return Scope_Suppress.Suppress (Length_Check);
|
|
end if;
|
|
end Length_Checks_Suppressed;
|
|
|
|
-----------------------
|
|
-- Make_Bignum_Block --
|
|
-----------------------
|
|
|
|
function Make_Bignum_Block (Loc : Source_Ptr) return Node_Id is
|
|
M : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uM);
|
|
begin
|
|
return
|
|
Make_Block_Statement (Loc,
|
|
Declarations =>
|
|
New_List (Build_SS_Mark_Call (Loc, M)),
|
|
Handled_Statement_Sequence =>
|
|
Make_Handled_Sequence_Of_Statements (Loc,
|
|
Statements => New_List (Build_SS_Release_Call (Loc, M))));
|
|
end Make_Bignum_Block;
|
|
|
|
----------------------------------
|
|
-- Minimize_Eliminate_Overflows --
|
|
----------------------------------
|
|
|
|
-- This is a recursive routine that is called at the top of an expression
|
|
-- tree to properly process overflow checking for a whole subtree by making
|
|
-- recursive calls to process operands. This processing may involve the use
|
|
-- of bignum or long long integer arithmetic, which will change the types
|
|
-- of operands and results. That's why we can't do this bottom up (since
|
|
-- it would interfere with semantic analysis).
|
|
|
|
-- What happens is that if MINIMIZED/ELIMINATED mode is in effect then
|
|
-- the operator expansion routines, as well as the expansion routines for
|
|
-- if/case expression, do nothing (for the moment) except call the routine
|
|
-- to apply the overflow check (Apply_Arithmetic_Overflow_Check). That
|
|
-- routine does nothing for non top-level nodes, so at the point where the
|
|
-- call is made for the top level node, the entire expression subtree has
|
|
-- not been expanded, or processed for overflow. All that has to happen as
|
|
-- a result of the top level call to this routine.
|
|
|
|
-- As noted above, the overflow processing works by making recursive calls
|
|
-- for the operands, and figuring out what to do, based on the processing
|
|
-- of these operands (e.g. if a bignum operand appears, the parent op has
|
|
-- to be done in bignum mode), and the determined ranges of the operands.
|
|
|
|
-- After possible rewriting of a constituent subexpression node, a call is
|
|
-- made to either reexpand the node (if nothing has changed) or reanalyze
|
|
-- the node (if it has been modified by the overflow check processing). The
|
|
-- Analyzed_Flag is set to False before the reexpand/reanalyze. To avoid
|
|
-- a recursive call into the whole overflow apparatus, an important rule
|
|
-- for this call is that the overflow handling mode must be temporarily set
|
|
-- to STRICT.
|
|
|
|
procedure Minimize_Eliminate_Overflows
|
|
(N : Node_Id;
|
|
Lo : out Uint;
|
|
Hi : out Uint;
|
|
Top_Level : Boolean)
|
|
is
|
|
Rtyp : constant Entity_Id := Etype (N);
|
|
pragma Assert (Is_Signed_Integer_Type (Rtyp));
|
|
-- Result type, must be a signed integer type
|
|
|
|
Check_Mode : constant Overflow_Mode_Type := Overflow_Check_Mode;
|
|
pragma Assert (Check_Mode in Minimized_Or_Eliminated);
|
|
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
|
|
Rlo, Rhi : Uint;
|
|
-- Ranges of values for right operand (operator case)
|
|
|
|
Llo, Lhi : Uint;
|
|
-- Ranges of values for left operand (operator case)
|
|
|
|
LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer);
|
|
-- Operands and results are of this type when we convert
|
|
|
|
LLLo : constant Uint := Intval (Type_Low_Bound (LLIB));
|
|
LLHi : constant Uint := Intval (Type_High_Bound (LLIB));
|
|
-- Bounds of Long_Long_Integer
|
|
|
|
Binary : constant Boolean := Nkind (N) in N_Binary_Op;
|
|
-- Indicates binary operator case
|
|
|
|
OK : Boolean;
|
|
-- Used in call to Determine_Range
|
|
|
|
Bignum_Operands : Boolean;
|
|
-- Set True if one or more operands is already of type Bignum, meaning
|
|
-- that for sure (regardless of Top_Level setting) we are committed to
|
|
-- doing the operation in Bignum mode (or in the case of a case or if
|
|
-- expression, converting all the dependent expressions to Bignum).
|
|
|
|
Long_Long_Integer_Operands : Boolean;
|
|
-- Set True if one or more operands is already of type Long_Long_Integer
|
|
-- which means that if the result is known to be in the result type
|
|
-- range, then we must convert such operands back to the result type.
|
|
|
|
procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False);
|
|
-- This is called when we have modified the node and we therefore need
|
|
-- to reanalyze it. It is important that we reset the mode to STRICT for
|
|
-- this reanalysis, since if we leave it in MINIMIZED or ELIMINATED mode
|
|
-- we would reenter this routine recursively which would not be good.
|
|
-- The argument Suppress is set True if we also want to suppress
|
|
-- overflow checking for the reexpansion (this is set when we know
|
|
-- overflow is not possible). Typ is the type for the reanalysis.
|
|
|
|
procedure Reexpand (Suppress : Boolean := False);
|
|
-- This is like Reanalyze, but does not do the Analyze step, it only
|
|
-- does a reexpansion. We do this reexpansion in STRICT mode, so that
|
|
-- instead of reentering the MINIMIZED/ELIMINATED mode processing, we
|
|
-- follow the normal expansion path (e.g. converting A**4 to A**2**2).
|
|
-- Note that skipping reanalysis is not just an optimization, testing
|
|
-- has showed up several complex cases in which reanalyzing an already
|
|
-- analyzed node causes incorrect behavior.
|
|
|
|
function In_Result_Range return Boolean;
|
|
-- Returns True iff Lo .. Hi are within range of the result type
|
|
|
|
procedure Max (A : in out Uint; B : Uint);
|
|
-- If A is No_Uint, sets A to B, else to UI_Max (A, B)
|
|
|
|
procedure Min (A : in out Uint; B : Uint);
|
|
-- If A is No_Uint, sets A to B, else to UI_Min (A, B)
|
|
|
|
---------------------
|
|
-- In_Result_Range --
|
|
---------------------
|
|
|
|
function In_Result_Range return Boolean is
|
|
begin
|
|
if Lo = No_Uint or else Hi = No_Uint then
|
|
return False;
|
|
|
|
elsif Is_OK_Static_Subtype (Etype (N)) then
|
|
return Lo >= Expr_Value (Type_Low_Bound (Rtyp))
|
|
and then
|
|
Hi <= Expr_Value (Type_High_Bound (Rtyp));
|
|
|
|
else
|
|
return Lo >= Expr_Value (Type_Low_Bound (Base_Type (Rtyp)))
|
|
and then
|
|
Hi <= Expr_Value (Type_High_Bound (Base_Type (Rtyp)));
|
|
end if;
|
|
end In_Result_Range;
|
|
|
|
---------
|
|
-- Max --
|
|
---------
|
|
|
|
procedure Max (A : in out Uint; B : Uint) is
|
|
begin
|
|
if A = No_Uint or else B > A then
|
|
A := B;
|
|
end if;
|
|
end Max;
|
|
|
|
---------
|
|
-- Min --
|
|
---------
|
|
|
|
procedure Min (A : in out Uint; B : Uint) is
|
|
begin
|
|
if A = No_Uint or else B < A then
|
|
A := B;
|
|
end if;
|
|
end Min;
|
|
|
|
---------------
|
|
-- Reanalyze --
|
|
---------------
|
|
|
|
procedure Reanalyze (Typ : Entity_Id; Suppress : Boolean := False) is
|
|
Svg : constant Overflow_Mode_Type :=
|
|
Scope_Suppress.Overflow_Mode_General;
|
|
Sva : constant Overflow_Mode_Type :=
|
|
Scope_Suppress.Overflow_Mode_Assertions;
|
|
Svo : constant Boolean :=
|
|
Scope_Suppress.Suppress (Overflow_Check);
|
|
|
|
begin
|
|
Scope_Suppress.Overflow_Mode_General := Strict;
|
|
Scope_Suppress.Overflow_Mode_Assertions := Strict;
|
|
|
|
if Suppress then
|
|
Scope_Suppress.Suppress (Overflow_Check) := True;
|
|
end if;
|
|
|
|
Analyze_And_Resolve (N, Typ);
|
|
|
|
Scope_Suppress.Suppress (Overflow_Check) := Svo;
|
|
Scope_Suppress.Overflow_Mode_General := Svg;
|
|
Scope_Suppress.Overflow_Mode_Assertions := Sva;
|
|
end Reanalyze;
|
|
|
|
--------------
|
|
-- Reexpand --
|
|
--------------
|
|
|
|
procedure Reexpand (Suppress : Boolean := False) is
|
|
Svg : constant Overflow_Mode_Type :=
|
|
Scope_Suppress.Overflow_Mode_General;
|
|
Sva : constant Overflow_Mode_Type :=
|
|
Scope_Suppress.Overflow_Mode_Assertions;
|
|
Svo : constant Boolean :=
|
|
Scope_Suppress.Suppress (Overflow_Check);
|
|
|
|
begin
|
|
Scope_Suppress.Overflow_Mode_General := Strict;
|
|
Scope_Suppress.Overflow_Mode_Assertions := Strict;
|
|
Set_Analyzed (N, False);
|
|
|
|
if Suppress then
|
|
Scope_Suppress.Suppress (Overflow_Check) := True;
|
|
end if;
|
|
|
|
Expand (N);
|
|
|
|
Scope_Suppress.Suppress (Overflow_Check) := Svo;
|
|
Scope_Suppress.Overflow_Mode_General := Svg;
|
|
Scope_Suppress.Overflow_Mode_Assertions := Sva;
|
|
end Reexpand;
|
|
|
|
-- Start of processing for Minimize_Eliminate_Overflows
|
|
|
|
begin
|
|
-- Case where we do not have a signed integer arithmetic operation
|
|
|
|
if not Is_Signed_Integer_Arithmetic_Op (N) then
|
|
|
|
-- Use the normal Determine_Range routine to get the range. We
|
|
-- don't require operands to be valid, invalid values may result in
|
|
-- rubbish results where the result has not been properly checked for
|
|
-- overflow, that's fine.
|
|
|
|
Determine_Range (N, OK, Lo, Hi, Assume_Valid => False);
|
|
|
|
-- If Determine_Range did not work (can this in fact happen? Not
|
|
-- clear but might as well protect), use type bounds.
|
|
|
|
if not OK then
|
|
Lo := Intval (Type_Low_Bound (Base_Type (Etype (N))));
|
|
Hi := Intval (Type_High_Bound (Base_Type (Etype (N))));
|
|
end if;
|
|
|
|
-- If we don't have a binary operator, all we have to do is to set
|
|
-- the Hi/Lo range, so we are done.
|
|
|
|
return;
|
|
|
|
-- Processing for if expression
|
|
|
|
elsif Nkind (N) = N_If_Expression then
|
|
declare
|
|
Then_DE : constant Node_Id := Next (First (Expressions (N)));
|
|
Else_DE : constant Node_Id := Next (Then_DE);
|
|
|
|
begin
|
|
Bignum_Operands := False;
|
|
|
|
Minimize_Eliminate_Overflows
|
|
(Then_DE, Lo, Hi, Top_Level => False);
|
|
|
|
if Lo = No_Uint then
|
|
Bignum_Operands := True;
|
|
end if;
|
|
|
|
Minimize_Eliminate_Overflows
|
|
(Else_DE, Rlo, Rhi, Top_Level => False);
|
|
|
|
if Rlo = No_Uint then
|
|
Bignum_Operands := True;
|
|
else
|
|
Long_Long_Integer_Operands :=
|
|
Etype (Then_DE) = LLIB or else Etype (Else_DE) = LLIB;
|
|
|
|
Min (Lo, Rlo);
|
|
Max (Hi, Rhi);
|
|
end if;
|
|
|
|
-- If at least one of our operands is now Bignum, we must rebuild
|
|
-- the if expression to use Bignum operands. We will analyze the
|
|
-- rebuilt if expression with overflow checks off, since once we
|
|
-- are in bignum mode, we are all done with overflow checks.
|
|
|
|
if Bignum_Operands then
|
|
Rewrite (N,
|
|
Make_If_Expression (Loc,
|
|
Expressions => New_List (
|
|
Remove_Head (Expressions (N)),
|
|
Convert_To_Bignum (Then_DE),
|
|
Convert_To_Bignum (Else_DE)),
|
|
Is_Elsif => Is_Elsif (N)));
|
|
|
|
Reanalyze (RTE (RE_Bignum), Suppress => True);
|
|
|
|
-- If we have no Long_Long_Integer operands, then we are in result
|
|
-- range, since it means that none of our operands felt the need
|
|
-- to worry about overflow (otherwise it would have already been
|
|
-- converted to long long integer or bignum). We reexpand to
|
|
-- complete the expansion of the if expression (but we do not
|
|
-- need to reanalyze).
|
|
|
|
elsif not Long_Long_Integer_Operands then
|
|
Set_Do_Overflow_Check (N, False);
|
|
Reexpand;
|
|
|
|
-- Otherwise convert us to long long integer mode. Note that we
|
|
-- don't need any further overflow checking at this level.
|
|
|
|
else
|
|
Convert_To_And_Rewrite (LLIB, Then_DE);
|
|
Convert_To_And_Rewrite (LLIB, Else_DE);
|
|
Set_Etype (N, LLIB);
|
|
|
|
-- Now reanalyze with overflow checks off
|
|
|
|
Set_Do_Overflow_Check (N, False);
|
|
Reanalyze (LLIB, Suppress => True);
|
|
end if;
|
|
end;
|
|
|
|
return;
|
|
|
|
-- Here for case expression
|
|
|
|
elsif Nkind (N) = N_Case_Expression then
|
|
Bignum_Operands := False;
|
|
Long_Long_Integer_Operands := False;
|
|
|
|
declare
|
|
Alt : Node_Id;
|
|
|
|
begin
|
|
-- Loop through expressions applying recursive call
|
|
|
|
Alt := First (Alternatives (N));
|
|
while Present (Alt) loop
|
|
declare
|
|
Aexp : constant Node_Id := Expression (Alt);
|
|
|
|
begin
|
|
Minimize_Eliminate_Overflows
|
|
(Aexp, Lo, Hi, Top_Level => False);
|
|
|
|
if Lo = No_Uint then
|
|
Bignum_Operands := True;
|
|
elsif Etype (Aexp) = LLIB then
|
|
Long_Long_Integer_Operands := True;
|
|
end if;
|
|
end;
|
|
|
|
Next (Alt);
|
|
end loop;
|
|
|
|
-- If we have no bignum or long long integer operands, it means
|
|
-- that none of our dependent expressions could raise overflow.
|
|
-- In this case, we simply return with no changes except for
|
|
-- resetting the overflow flag, since we are done with overflow
|
|
-- checks for this node. We will reexpand to get the needed
|
|
-- expansion for the case expression, but we do not need to
|
|
-- reanalyze, since nothing has changed.
|
|
|
|
if not (Bignum_Operands or Long_Long_Integer_Operands) then
|
|
Set_Do_Overflow_Check (N, False);
|
|
Reexpand (Suppress => True);
|
|
|
|
-- Otherwise we are going to rebuild the case expression using
|
|
-- either bignum or long long integer operands throughout.
|
|
|
|
else
|
|
declare
|
|
Rtype : Entity_Id;
|
|
New_Alts : List_Id;
|
|
New_Exp : Node_Id;
|
|
|
|
begin
|
|
New_Alts := New_List;
|
|
Alt := First (Alternatives (N));
|
|
while Present (Alt) loop
|
|
if Bignum_Operands then
|
|
New_Exp := Convert_To_Bignum (Expression (Alt));
|
|
Rtype := RTE (RE_Bignum);
|
|
else
|
|
New_Exp := Convert_To (LLIB, Expression (Alt));
|
|
Rtype := LLIB;
|
|
end if;
|
|
|
|
Append_To (New_Alts,
|
|
Make_Case_Expression_Alternative (Sloc (Alt),
|
|
Actions => No_List,
|
|
Discrete_Choices => Discrete_Choices (Alt),
|
|
Expression => New_Exp));
|
|
|
|
Next (Alt);
|
|
end loop;
|
|
|
|
Rewrite (N,
|
|
Make_Case_Expression (Loc,
|
|
Expression => Expression (N),
|
|
Alternatives => New_Alts));
|
|
|
|
Reanalyze (Rtype, Suppress => True);
|
|
end;
|
|
end if;
|
|
end;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- If we have an arithmetic operator we make recursive calls on the
|
|
-- operands to get the ranges (and to properly process the subtree
|
|
-- that lies below us).
|
|
|
|
Minimize_Eliminate_Overflows
|
|
(Right_Opnd (N), Rlo, Rhi, Top_Level => False);
|
|
|
|
if Binary then
|
|
Minimize_Eliminate_Overflows
|
|
(Left_Opnd (N), Llo, Lhi, Top_Level => False);
|
|
end if;
|
|
|
|
-- Record if we have Long_Long_Integer operands
|
|
|
|
Long_Long_Integer_Operands :=
|
|
Etype (Right_Opnd (N)) = LLIB
|
|
or else (Binary and then Etype (Left_Opnd (N)) = LLIB);
|
|
|
|
-- If either operand is a bignum, then result will be a bignum and we
|
|
-- don't need to do any range analysis. As previously discussed we could
|
|
-- do range analysis in such cases, but it could mean working with giant
|
|
-- numbers at compile time for very little gain (the number of cases
|
|
-- in which we could slip back from bignum mode is small).
|
|
|
|
if Rlo = No_Uint or else (Binary and then Llo = No_Uint) then
|
|
Lo := No_Uint;
|
|
Hi := No_Uint;
|
|
Bignum_Operands := True;
|
|
|
|
-- Otherwise compute result range
|
|
|
|
else
|
|
Bignum_Operands := False;
|
|
|
|
case Nkind (N) is
|
|
|
|
-- Absolute value
|
|
|
|
when N_Op_Abs =>
|
|
Lo := Uint_0;
|
|
Hi := UI_Max (abs Rlo, abs Rhi);
|
|
|
|
-- Addition
|
|
|
|
when N_Op_Add =>
|
|
Lo := Llo + Rlo;
|
|
Hi := Lhi + Rhi;
|
|
|
|
-- Division
|
|
|
|
when N_Op_Divide =>
|
|
|
|
-- If the right operand can only be zero, set 0..0
|
|
|
|
if Rlo = 0 and then Rhi = 0 then
|
|
Lo := Uint_0;
|
|
Hi := Uint_0;
|
|
|
|
-- Possible bounds of division must come from dividing end
|
|
-- values of the input ranges (four possibilities), provided
|
|
-- zero is not included in the possible values of the right
|
|
-- operand.
|
|
|
|
-- Otherwise, we just consider two intervals of values for
|
|
-- the right operand: the interval of negative values (up to
|
|
-- -1) and the interval of positive values (starting at 1).
|
|
-- Since division by 1 is the identity, and division by -1
|
|
-- is negation, we get all possible bounds of division in that
|
|
-- case by considering:
|
|
-- - all values from the division of end values of input
|
|
-- ranges;
|
|
-- - the end values of the left operand;
|
|
-- - the negation of the end values of the left operand.
|
|
|
|
else
|
|
declare
|
|
Mrk : constant Uintp.Save_Mark := Mark;
|
|
-- Mark so we can release the RR and Ev values
|
|
|
|
Ev1 : Uint;
|
|
Ev2 : Uint;
|
|
Ev3 : Uint;
|
|
Ev4 : Uint;
|
|
|
|
begin
|
|
-- Discard extreme values of zero for the divisor, since
|
|
-- they will simply result in an exception in any case.
|
|
|
|
if Rlo = 0 then
|
|
Rlo := Uint_1;
|
|
elsif Rhi = 0 then
|
|
Rhi := -Uint_1;
|
|
end if;
|
|
|
|
-- Compute possible bounds coming from dividing end
|
|
-- values of the input ranges.
|
|
|
|
Ev1 := Llo / Rlo;
|
|
Ev2 := Llo / Rhi;
|
|
Ev3 := Lhi / Rlo;
|
|
Ev4 := Lhi / Rhi;
|
|
|
|
Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4));
|
|
Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4));
|
|
|
|
-- If the right operand can be both negative or positive,
|
|
-- include the end values of the left operand in the
|
|
-- extreme values, as well as their negation.
|
|
|
|
if Rlo < 0 and then Rhi > 0 then
|
|
Ev1 := Llo;
|
|
Ev2 := -Llo;
|
|
Ev3 := Lhi;
|
|
Ev4 := -Lhi;
|
|
|
|
Min (Lo,
|
|
UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4)));
|
|
Max (Hi,
|
|
UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4)));
|
|
end if;
|
|
|
|
-- Release the RR and Ev values
|
|
|
|
Release_And_Save (Mrk, Lo, Hi);
|
|
end;
|
|
end if;
|
|
|
|
-- Exponentiation
|
|
|
|
when N_Op_Expon =>
|
|
|
|
-- Discard negative values for the exponent, since they will
|
|
-- simply result in an exception in any case.
|
|
|
|
if Rhi < 0 then
|
|
Rhi := Uint_0;
|
|
elsif Rlo < 0 then
|
|
Rlo := Uint_0;
|
|
end if;
|
|
|
|
-- Estimate number of bits in result before we go computing
|
|
-- giant useless bounds. Basically the number of bits in the
|
|
-- result is the number of bits in the base multiplied by the
|
|
-- value of the exponent. If this is big enough that the result
|
|
-- definitely won't fit in Long_Long_Integer, switch to bignum
|
|
-- mode immediately, and avoid computing giant bounds.
|
|
|
|
-- The comparison here is approximate, but conservative, it
|
|
-- only clicks on cases that are sure to exceed the bounds.
|
|
|
|
if Num_Bits (UI_Max (abs Llo, abs Lhi)) * Rhi + 1 > 100 then
|
|
Lo := No_Uint;
|
|
Hi := No_Uint;
|
|
|
|
-- If right operand is zero then result is 1
|
|
|
|
elsif Rhi = 0 then
|
|
Lo := Uint_1;
|
|
Hi := Uint_1;
|
|
|
|
else
|
|
-- High bound comes either from exponentiation of largest
|
|
-- positive value to largest exponent value, or from
|
|
-- the exponentiation of most negative value to an
|
|
-- even exponent.
|
|
|
|
declare
|
|
Hi1, Hi2 : Uint;
|
|
|
|
begin
|
|
if Lhi > 0 then
|
|
Hi1 := Lhi ** Rhi;
|
|
else
|
|
Hi1 := Uint_0;
|
|
end if;
|
|
|
|
if Llo < 0 then
|
|
if Rhi mod 2 = 0 then
|
|
Hi2 := Llo ** Rhi;
|
|
else
|
|
Hi2 := Llo ** (Rhi - 1);
|
|
end if;
|
|
else
|
|
Hi2 := Uint_0;
|
|
end if;
|
|
|
|
Hi := UI_Max (Hi1, Hi2);
|
|
end;
|
|
|
|
-- Result can only be negative if base can be negative
|
|
|
|
if Llo < 0 then
|
|
if Rhi mod 2 = 0 then
|
|
Lo := Llo ** (Rhi - 1);
|
|
else
|
|
Lo := Llo ** Rhi;
|
|
end if;
|
|
|
|
-- Otherwise low bound is minimum ** minimum
|
|
|
|
else
|
|
Lo := Llo ** Rlo;
|
|
end if;
|
|
end if;
|
|
|
|
-- Negation
|
|
|
|
when N_Op_Minus =>
|
|
Lo := -Rhi;
|
|
Hi := -Rlo;
|
|
|
|
-- Mod
|
|
|
|
when N_Op_Mod =>
|
|
declare
|
|
Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1;
|
|
-- This is the maximum absolute value of the result
|
|
|
|
begin
|
|
Lo := Uint_0;
|
|
Hi := Uint_0;
|
|
|
|
-- The result depends only on the sign and magnitude of
|
|
-- the right operand, it does not depend on the sign or
|
|
-- magnitude of the left operand.
|
|
|
|
if Rlo < 0 then
|
|
Lo := -Maxabs;
|
|
end if;
|
|
|
|
if Rhi > 0 then
|
|
Hi := Maxabs;
|
|
end if;
|
|
end;
|
|
|
|
-- Multiplication
|
|
|
|
when N_Op_Multiply =>
|
|
|
|
-- Possible bounds of multiplication must come from multiplying
|
|
-- end values of the input ranges (four possibilities).
|
|
|
|
declare
|
|
Mrk : constant Uintp.Save_Mark := Mark;
|
|
-- Mark so we can release the Ev values
|
|
|
|
Ev1 : constant Uint := Llo * Rlo;
|
|
Ev2 : constant Uint := Llo * Rhi;
|
|
Ev3 : constant Uint := Lhi * Rlo;
|
|
Ev4 : constant Uint := Lhi * Rhi;
|
|
|
|
begin
|
|
Lo := UI_Min (UI_Min (Ev1, Ev2), UI_Min (Ev3, Ev4));
|
|
Hi := UI_Max (UI_Max (Ev1, Ev2), UI_Max (Ev3, Ev4));
|
|
|
|
-- Release the Ev values
|
|
|
|
Release_And_Save (Mrk, Lo, Hi);
|
|
end;
|
|
|
|
-- Plus operator (affirmation)
|
|
|
|
when N_Op_Plus =>
|
|
Lo := Rlo;
|
|
Hi := Rhi;
|
|
|
|
-- Remainder
|
|
|
|
when N_Op_Rem =>
|
|
declare
|
|
Maxabs : constant Uint := UI_Max (abs Rlo, abs Rhi) - 1;
|
|
-- This is the maximum absolute value of the result. Note
|
|
-- that the result range does not depend on the sign of the
|
|
-- right operand.
|
|
|
|
begin
|
|
Lo := Uint_0;
|
|
Hi := Uint_0;
|
|
|
|
-- Case of left operand negative, which results in a range
|
|
-- of -Maxabs .. 0 for those negative values. If there are
|
|
-- no negative values then Lo value of result is always 0.
|
|
|
|
if Llo < 0 then
|
|
Lo := -Maxabs;
|
|
end if;
|
|
|
|
-- Case of left operand positive
|
|
|
|
if Lhi > 0 then
|
|
Hi := Maxabs;
|
|
end if;
|
|
end;
|
|
|
|
-- Subtract
|
|
|
|
when N_Op_Subtract =>
|
|
Lo := Llo - Rhi;
|
|
Hi := Lhi - Rlo;
|
|
|
|
-- Nothing else should be possible
|
|
|
|
when others =>
|
|
raise Program_Error;
|
|
end case;
|
|
end if;
|
|
|
|
-- Here for the case where we have not rewritten anything (no bignum
|
|
-- operands or long long integer operands), and we know the result.
|
|
-- If we know we are in the result range, and we do not have Bignum
|
|
-- operands or Long_Long_Integer operands, we can just reexpand with
|
|
-- overflow checks turned off (since we know we cannot have overflow).
|
|
-- As always the reexpansion is required to complete expansion of the
|
|
-- operator, but we do not need to reanalyze, and we prevent recursion
|
|
-- by suppressing the check.
|
|
|
|
if not (Bignum_Operands or Long_Long_Integer_Operands)
|
|
and then In_Result_Range
|
|
then
|
|
Set_Do_Overflow_Check (N, False);
|
|
Reexpand (Suppress => True);
|
|
return;
|
|
|
|
-- Here we know that we are not in the result range, and in the general
|
|
-- case we will move into either the Bignum or Long_Long_Integer domain
|
|
-- to compute the result. However, there is one exception. If we are
|
|
-- at the top level, and we do not have Bignum or Long_Long_Integer
|
|
-- operands, we will have to immediately convert the result back to
|
|
-- the result type, so there is no point in Bignum/Long_Long_Integer
|
|
-- fiddling.
|
|
|
|
elsif Top_Level
|
|
and then not (Bignum_Operands or Long_Long_Integer_Operands)
|
|
|
|
-- One further refinement. If we are at the top level, but our parent
|
|
-- is a type conversion, then go into bignum or long long integer node
|
|
-- since the result will be converted to that type directly without
|
|
-- going through the result type, and we may avoid an overflow. This
|
|
-- is the case for example of Long_Long_Integer (A ** 4), where A is
|
|
-- of type Integer, and the result A ** 4 fits in Long_Long_Integer
|
|
-- but does not fit in Integer.
|
|
|
|
and then Nkind (Parent (N)) /= N_Type_Conversion
|
|
then
|
|
-- Here keep original types, but we need to complete analysis
|
|
|
|
-- One subtlety. We can't just go ahead and do an analyze operation
|
|
-- here because it will cause recursion into the whole MINIMIZED/
|
|
-- ELIMINATED overflow processing which is not what we want. Here
|
|
-- we are at the top level, and we need a check against the result
|
|
-- mode (i.e. we want to use STRICT mode). So do exactly that.
|
|
-- Also, we have not modified the node, so this is a case where
|
|
-- we need to reexpand, but not reanalyze.
|
|
|
|
Reexpand;
|
|
return;
|
|
|
|
-- Cases where we do the operation in Bignum mode. This happens either
|
|
-- because one of our operands is in Bignum mode already, or because
|
|
-- the computed bounds are outside the bounds of Long_Long_Integer,
|
|
-- which in some cases can be indicated by Hi and Lo being No_Uint.
|
|
|
|
-- Note: we could do better here and in some cases switch back from
|
|
-- Bignum mode to normal mode, e.g. big mod 2 must be in the range
|
|
-- 0 .. 1, but the cases are rare and it is not worth the effort.
|
|
-- Failing to do this switching back is only an efficiency issue.
|
|
|
|
elsif Lo = No_Uint or else Lo < LLLo or else Hi > LLHi then
|
|
|
|
-- OK, we are definitely outside the range of Long_Long_Integer. The
|
|
-- question is whether to move to Bignum mode, or stay in the domain
|
|
-- of Long_Long_Integer, signalling that an overflow check is needed.
|
|
|
|
-- Obviously in MINIMIZED mode we stay with LLI, since we are not in
|
|
-- the Bignum business. In ELIMINATED mode, we will normally move
|
|
-- into Bignum mode, but there is an exception if neither of our
|
|
-- operands is Bignum now, and we are at the top level (Top_Level
|
|
-- set True). In this case, there is no point in moving into Bignum
|
|
-- mode to prevent overflow if the caller will immediately convert
|
|
-- the Bignum value back to LLI with an overflow check. It's more
|
|
-- efficient to stay in LLI mode with an overflow check (if needed)
|
|
|
|
if Check_Mode = Minimized
|
|
or else (Top_Level and not Bignum_Operands)
|
|
then
|
|
if Do_Overflow_Check (N) then
|
|
Enable_Overflow_Check (N);
|
|
end if;
|
|
|
|
-- The result now has to be in Long_Long_Integer mode, so adjust
|
|
-- the possible range to reflect this. Note these calls also
|
|
-- change No_Uint values from the top level case to LLI bounds.
|
|
|
|
Max (Lo, LLLo);
|
|
Min (Hi, LLHi);
|
|
|
|
-- Otherwise we are in ELIMINATED mode and we switch to Bignum mode
|
|
|
|
else
|
|
pragma Assert (Check_Mode = Eliminated);
|
|
|
|
declare
|
|
Fent : Entity_Id;
|
|
Args : List_Id;
|
|
|
|
begin
|
|
case Nkind (N) is
|
|
when N_Op_Abs =>
|
|
Fent := RTE (RE_Big_Abs);
|
|
|
|
when N_Op_Add =>
|
|
Fent := RTE (RE_Big_Add);
|
|
|
|
when N_Op_Divide =>
|
|
Fent := RTE (RE_Big_Div);
|
|
|
|
when N_Op_Expon =>
|
|
Fent := RTE (RE_Big_Exp);
|
|
|
|
when N_Op_Minus =>
|
|
Fent := RTE (RE_Big_Neg);
|
|
|
|
when N_Op_Mod =>
|
|
Fent := RTE (RE_Big_Mod);
|
|
|
|
when N_Op_Multiply =>
|
|
Fent := RTE (RE_Big_Mul);
|
|
|
|
when N_Op_Rem =>
|
|
Fent := RTE (RE_Big_Rem);
|
|
|
|
when N_Op_Subtract =>
|
|
Fent := RTE (RE_Big_Sub);
|
|
|
|
-- Anything else is an internal error, this includes the
|
|
-- N_Op_Plus case, since how can plus cause the result
|
|
-- to be out of range if the operand is in range?
|
|
|
|
when others =>
|
|
raise Program_Error;
|
|
end case;
|
|
|
|
-- Construct argument list for Bignum call, converting our
|
|
-- operands to Bignum form if they are not already there.
|
|
|
|
Args := New_List;
|
|
|
|
if Binary then
|
|
Append_To (Args, Convert_To_Bignum (Left_Opnd (N)));
|
|
end if;
|
|
|
|
Append_To (Args, Convert_To_Bignum (Right_Opnd (N)));
|
|
|
|
-- Now rewrite the arithmetic operator with a call to the
|
|
-- corresponding bignum function.
|
|
|
|
Rewrite (N,
|
|
Make_Function_Call (Loc,
|
|
Name => New_Occurrence_Of (Fent, Loc),
|
|
Parameter_Associations => Args));
|
|
Reanalyze (RTE (RE_Bignum), Suppress => True);
|
|
|
|
-- Indicate result is Bignum mode
|
|
|
|
Lo := No_Uint;
|
|
Hi := No_Uint;
|
|
return;
|
|
end;
|
|
end if;
|
|
|
|
-- Otherwise we are in range of Long_Long_Integer, so no overflow
|
|
-- check is required, at least not yet.
|
|
|
|
else
|
|
Set_Do_Overflow_Check (N, False);
|
|
end if;
|
|
|
|
-- Here we are not in Bignum territory, but we may have long long
|
|
-- integer operands that need special handling. First a special check:
|
|
-- If an exponentiation operator exponent is of type Long_Long_Integer,
|
|
-- it means we converted it to prevent overflow, but exponentiation
|
|
-- requires a Natural right operand, so convert it back to Natural.
|
|
-- This conversion may raise an exception which is fine.
|
|
|
|
if Nkind (N) = N_Op_Expon and then Etype (Right_Opnd (N)) = LLIB then
|
|
Convert_To_And_Rewrite (Standard_Natural, Right_Opnd (N));
|
|
end if;
|
|
|
|
-- Here we will do the operation in Long_Long_Integer. We do this even
|
|
-- if we know an overflow check is required, better to do this in long
|
|
-- long integer mode, since we are less likely to overflow.
|
|
|
|
-- Convert right or only operand to Long_Long_Integer, except that
|
|
-- we do not touch the exponentiation right operand.
|
|
|
|
if Nkind (N) /= N_Op_Expon then
|
|
Convert_To_And_Rewrite (LLIB, Right_Opnd (N));
|
|
end if;
|
|
|
|
-- Convert left operand to Long_Long_Integer for binary case
|
|
|
|
if Binary then
|
|
Convert_To_And_Rewrite (LLIB, Left_Opnd (N));
|
|
end if;
|
|
|
|
-- Reset node to unanalyzed
|
|
|
|
Set_Analyzed (N, False);
|
|
Set_Etype (N, Empty);
|
|
Set_Entity (N, Empty);
|
|
|
|
-- Now analyze this new node. This reanalysis will complete processing
|
|
-- for the node. In particular we will complete the expansion of an
|
|
-- exponentiation operator (e.g. changing A ** 2 to A * A), and also
|
|
-- we will complete any division checks (since we have not changed the
|
|
-- setting of the Do_Division_Check flag).
|
|
|
|
-- We do this reanalysis in STRICT mode to avoid recursion into the
|
|
-- MINIMIZED/ELIMINATED handling, since we are now done with that.
|
|
|
|
declare
|
|
SG : constant Overflow_Mode_Type :=
|
|
Scope_Suppress.Overflow_Mode_General;
|
|
SA : constant Overflow_Mode_Type :=
|
|
Scope_Suppress.Overflow_Mode_Assertions;
|
|
|
|
begin
|
|
Scope_Suppress.Overflow_Mode_General := Strict;
|
|
Scope_Suppress.Overflow_Mode_Assertions := Strict;
|
|
|
|
if not Do_Overflow_Check (N) then
|
|
Reanalyze (LLIB, Suppress => True);
|
|
else
|
|
Reanalyze (LLIB);
|
|
end if;
|
|
|
|
Scope_Suppress.Overflow_Mode_General := SG;
|
|
Scope_Suppress.Overflow_Mode_Assertions := SA;
|
|
end;
|
|
end Minimize_Eliminate_Overflows;
|
|
|
|
-------------------------
|
|
-- Overflow_Check_Mode --
|
|
-------------------------
|
|
|
|
function Overflow_Check_Mode return Overflow_Mode_Type is
|
|
begin
|
|
if In_Assertion_Expr = 0 then
|
|
return Scope_Suppress.Overflow_Mode_General;
|
|
else
|
|
return Scope_Suppress.Overflow_Mode_Assertions;
|
|
end if;
|
|
end Overflow_Check_Mode;
|
|
|
|
--------------------------------
|
|
-- Overflow_Checks_Suppressed --
|
|
--------------------------------
|
|
|
|
function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) and then Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Overflow_Check);
|
|
else
|
|
return Scope_Suppress.Suppress (Overflow_Check);
|
|
end if;
|
|
end Overflow_Checks_Suppressed;
|
|
|
|
---------------------------------
|
|
-- Predicate_Checks_Suppressed --
|
|
---------------------------------
|
|
|
|
function Predicate_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) and then Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Predicate_Check);
|
|
else
|
|
return Scope_Suppress.Suppress (Predicate_Check);
|
|
end if;
|
|
end Predicate_Checks_Suppressed;
|
|
|
|
-----------------------------
|
|
-- Range_Checks_Suppressed --
|
|
-----------------------------
|
|
|
|
function Range_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) then
|
|
if Kill_Range_Checks (E) then
|
|
return True;
|
|
|
|
elsif Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Range_Check);
|
|
end if;
|
|
end if;
|
|
|
|
return Scope_Suppress.Suppress (Range_Check);
|
|
end Range_Checks_Suppressed;
|
|
|
|
-----------------------------------------
|
|
-- Range_Or_Validity_Checks_Suppressed --
|
|
-----------------------------------------
|
|
|
|
-- Note: the coding would be simpler here if we simply made appropriate
|
|
-- calls to Range/Validity_Checks_Suppressed, but that would result in
|
|
-- duplicated checks which we prefer to avoid.
|
|
|
|
function Range_Or_Validity_Checks_Suppressed
|
|
(Expr : Node_Id) return Boolean
|
|
is
|
|
begin
|
|
-- Immediate return if scope checks suppressed for either check
|
|
|
|
if Scope_Suppress.Suppress (Range_Check)
|
|
or
|
|
Scope_Suppress.Suppress (Validity_Check)
|
|
then
|
|
return True;
|
|
end if;
|
|
|
|
-- If no expression, that's odd, decide that checks are suppressed,
|
|
-- since we don't want anyone trying to do checks in this case, which
|
|
-- is most likely the result of some other error.
|
|
|
|
if No (Expr) then
|
|
return True;
|
|
end if;
|
|
|
|
-- Expression is present, so perform suppress checks on type
|
|
|
|
declare
|
|
Typ : constant Entity_Id := Etype (Expr);
|
|
begin
|
|
if Checks_May_Be_Suppressed (Typ)
|
|
and then (Is_Check_Suppressed (Typ, Range_Check)
|
|
or else
|
|
Is_Check_Suppressed (Typ, Validity_Check))
|
|
then
|
|
return True;
|
|
end if;
|
|
end;
|
|
|
|
-- If expression is an entity name, perform checks on this entity
|
|
|
|
if Is_Entity_Name (Expr) then
|
|
declare
|
|
Ent : constant Entity_Id := Entity (Expr);
|
|
begin
|
|
if Checks_May_Be_Suppressed (Ent) then
|
|
return Is_Check_Suppressed (Ent, Range_Check)
|
|
or else Is_Check_Suppressed (Ent, Validity_Check);
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
-- If we fall through, no checks suppressed
|
|
|
|
return False;
|
|
end Range_Or_Validity_Checks_Suppressed;
|
|
|
|
-------------------
|
|
-- Remove_Checks --
|
|
-------------------
|
|
|
|
procedure Remove_Checks (Expr : Node_Id) is
|
|
function Process (N : Node_Id) return Traverse_Result;
|
|
-- Process a single node during the traversal
|
|
|
|
procedure Traverse is new Traverse_Proc (Process);
|
|
-- The traversal procedure itself
|
|
|
|
-------------
|
|
-- Process --
|
|
-------------
|
|
|
|
function Process (N : Node_Id) return Traverse_Result is
|
|
begin
|
|
if Nkind (N) not in N_Subexpr then
|
|
return Skip;
|
|
end if;
|
|
|
|
Set_Do_Range_Check (N, False);
|
|
|
|
case Nkind (N) is
|
|
when N_And_Then =>
|
|
Traverse (Left_Opnd (N));
|
|
return Skip;
|
|
|
|
when N_Attribute_Reference =>
|
|
Set_Do_Overflow_Check (N, False);
|
|
|
|
when N_Function_Call =>
|
|
Set_Do_Tag_Check (N, False);
|
|
|
|
when N_Op =>
|
|
Set_Do_Overflow_Check (N, False);
|
|
|
|
case Nkind (N) is
|
|
when N_Op_Divide =>
|
|
Set_Do_Division_Check (N, False);
|
|
|
|
when N_Op_And =>
|
|
Set_Do_Length_Check (N, False);
|
|
|
|
when N_Op_Mod =>
|
|
Set_Do_Division_Check (N, False);
|
|
|
|
when N_Op_Or =>
|
|
Set_Do_Length_Check (N, False);
|
|
|
|
when N_Op_Rem =>
|
|
Set_Do_Division_Check (N, False);
|
|
|
|
when N_Op_Xor =>
|
|
Set_Do_Length_Check (N, False);
|
|
|
|
when others =>
|
|
null;
|
|
end case;
|
|
|
|
when N_Or_Else =>
|
|
Traverse (Left_Opnd (N));
|
|
return Skip;
|
|
|
|
when N_Selected_Component =>
|
|
Set_Do_Discriminant_Check (N, False);
|
|
|
|
when N_Type_Conversion =>
|
|
Set_Do_Length_Check (N, False);
|
|
Set_Do_Tag_Check (N, False);
|
|
Set_Do_Overflow_Check (N, False);
|
|
|
|
when others =>
|
|
null;
|
|
end case;
|
|
|
|
return OK;
|
|
end Process;
|
|
|
|
-- Start of processing for Remove_Checks
|
|
|
|
begin
|
|
Traverse (Expr);
|
|
end Remove_Checks;
|
|
|
|
----------------------------
|
|
-- Selected_Length_Checks --
|
|
----------------------------
|
|
|
|
function Selected_Length_Checks
|
|
(Ck_Node : Node_Id;
|
|
Target_Typ : Entity_Id;
|
|
Source_Typ : Entity_Id;
|
|
Warn_Node : Node_Id) return Check_Result
|
|
is
|
|
Loc : constant Source_Ptr := Sloc (Ck_Node);
|
|
S_Typ : Entity_Id;
|
|
T_Typ : Entity_Id;
|
|
Expr_Actual : Node_Id;
|
|
Exptyp : Entity_Id;
|
|
Cond : Node_Id := Empty;
|
|
Do_Access : Boolean := False;
|
|
Wnode : Node_Id := Warn_Node;
|
|
Ret_Result : Check_Result := (Empty, Empty);
|
|
Num_Checks : Natural := 0;
|
|
|
|
procedure Add_Check (N : Node_Id);
|
|
-- Adds the action given to Ret_Result if N is non-Empty
|
|
|
|
function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id;
|
|
function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id;
|
|
-- Comments required ???
|
|
|
|
function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean;
|
|
-- True for equal literals and for nodes that denote the same constant
|
|
-- entity, even if its value is not a static constant. This includes the
|
|
-- case of a discriminal reference within an init proc. Removes some
|
|
-- obviously superfluous checks.
|
|
|
|
function Length_E_Cond
|
|
(Exptyp : Entity_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat) return Node_Id;
|
|
-- Returns expression to compute:
|
|
-- Typ'Length /= Exptyp'Length
|
|
|
|
function Length_N_Cond
|
|
(Expr : Node_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat) return Node_Id;
|
|
-- Returns expression to compute:
|
|
-- Typ'Length /= Expr'Length
|
|
|
|
---------------
|
|
-- Add_Check --
|
|
---------------
|
|
|
|
procedure Add_Check (N : Node_Id) is
|
|
begin
|
|
if Present (N) then
|
|
|
|
-- For now, ignore attempt to place more than two checks ???
|
|
-- This is really worrisome, are we really discarding checks ???
|
|
|
|
if Num_Checks = 2 then
|
|
return;
|
|
end if;
|
|
|
|
pragma Assert (Num_Checks <= 1);
|
|
Num_Checks := Num_Checks + 1;
|
|
Ret_Result (Num_Checks) := N;
|
|
end if;
|
|
end Add_Check;
|
|
|
|
------------------
|
|
-- Get_E_Length --
|
|
------------------
|
|
|
|
function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is
|
|
SE : constant Entity_Id := Scope (E);
|
|
N : Node_Id;
|
|
E1 : Entity_Id := E;
|
|
|
|
begin
|
|
if Ekind (Scope (E)) = E_Record_Type
|
|
and then Has_Discriminants (Scope (E))
|
|
then
|
|
N := Build_Discriminal_Subtype_Of_Component (E);
|
|
|
|
if Present (N) then
|
|
Insert_Action (Ck_Node, N);
|
|
E1 := Defining_Identifier (N);
|
|
end if;
|
|
end if;
|
|
|
|
if Ekind (E1) = E_String_Literal_Subtype then
|
|
return
|
|
Make_Integer_Literal (Loc,
|
|
Intval => String_Literal_Length (E1));
|
|
|
|
elsif SE /= Standard_Standard
|
|
and then Ekind (Scope (SE)) = E_Protected_Type
|
|
and then Has_Discriminants (Scope (SE))
|
|
and then Has_Completion (Scope (SE))
|
|
and then not Inside_Init_Proc
|
|
then
|
|
-- If the type whose length is needed is a private component
|
|
-- constrained by a discriminant, we must expand the 'Length
|
|
-- attribute into an explicit computation, using the discriminal
|
|
-- of the current protected operation. This is because the actual
|
|
-- type of the prival is constructed after the protected opera-
|
|
-- tion has been fully expanded.
|
|
|
|
declare
|
|
Indx_Type : Node_Id;
|
|
Lo : Node_Id;
|
|
Hi : Node_Id;
|
|
Do_Expand : Boolean := False;
|
|
|
|
begin
|
|
Indx_Type := First_Index (E);
|
|
|
|
for J in 1 .. Indx - 1 loop
|
|
Next_Index (Indx_Type);
|
|
end loop;
|
|
|
|
Get_Index_Bounds (Indx_Type, Lo, Hi);
|
|
|
|
if Nkind (Lo) = N_Identifier
|
|
and then Ekind (Entity (Lo)) = E_In_Parameter
|
|
then
|
|
Lo := Get_Discriminal (E, Lo);
|
|
Do_Expand := True;
|
|
end if;
|
|
|
|
if Nkind (Hi) = N_Identifier
|
|
and then Ekind (Entity (Hi)) = E_In_Parameter
|
|
then
|
|
Hi := Get_Discriminal (E, Hi);
|
|
Do_Expand := True;
|
|
end if;
|
|
|
|
if Do_Expand then
|
|
if not Is_Entity_Name (Lo) then
|
|
Lo := Duplicate_Subexpr_No_Checks (Lo);
|
|
end if;
|
|
|
|
if not Is_Entity_Name (Hi) then
|
|
Lo := Duplicate_Subexpr_No_Checks (Hi);
|
|
end if;
|
|
|
|
N :=
|
|
Make_Op_Add (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Subtract (Loc,
|
|
Left_Opnd => Hi,
|
|
Right_Opnd => Lo),
|
|
|
|
Right_Opnd => Make_Integer_Literal (Loc, 1));
|
|
return N;
|
|
|
|
else
|
|
N :=
|
|
Make_Attribute_Reference (Loc,
|
|
Attribute_Name => Name_Length,
|
|
Prefix =>
|
|
New_Occurrence_Of (E1, Loc));
|
|
|
|
if Indx > 1 then
|
|
Set_Expressions (N, New_List (
|
|
Make_Integer_Literal (Loc, Indx)));
|
|
end if;
|
|
|
|
return N;
|
|
end if;
|
|
end;
|
|
|
|
else
|
|
N :=
|
|
Make_Attribute_Reference (Loc,
|
|
Attribute_Name => Name_Length,
|
|
Prefix =>
|
|
New_Occurrence_Of (E1, Loc));
|
|
|
|
if Indx > 1 then
|
|
Set_Expressions (N, New_List (
|
|
Make_Integer_Literal (Loc, Indx)));
|
|
end if;
|
|
|
|
return N;
|
|
end if;
|
|
end Get_E_Length;
|
|
|
|
------------------
|
|
-- Get_N_Length --
|
|
------------------
|
|
|
|
function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is
|
|
begin
|
|
return
|
|
Make_Attribute_Reference (Loc,
|
|
Attribute_Name => Name_Length,
|
|
Prefix =>
|
|
Duplicate_Subexpr_No_Checks (N, Name_Req => True),
|
|
Expressions => New_List (
|
|
Make_Integer_Literal (Loc, Indx)));
|
|
end Get_N_Length;
|
|
|
|
-------------------
|
|
-- Length_E_Cond --
|
|
-------------------
|
|
|
|
function Length_E_Cond
|
|
(Exptyp : Entity_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat) return Node_Id
|
|
is
|
|
begin
|
|
return
|
|
Make_Op_Ne (Loc,
|
|
Left_Opnd => Get_E_Length (Typ, Indx),
|
|
Right_Opnd => Get_E_Length (Exptyp, Indx));
|
|
end Length_E_Cond;
|
|
|
|
-------------------
|
|
-- Length_N_Cond --
|
|
-------------------
|
|
|
|
function Length_N_Cond
|
|
(Expr : Node_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat) return Node_Id
|
|
is
|
|
begin
|
|
return
|
|
Make_Op_Ne (Loc,
|
|
Left_Opnd => Get_E_Length (Typ, Indx),
|
|
Right_Opnd => Get_N_Length (Expr, Indx));
|
|
end Length_N_Cond;
|
|
|
|
-----------------
|
|
-- Same_Bounds --
|
|
-----------------
|
|
|
|
function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is
|
|
begin
|
|
return
|
|
(Nkind (L) = N_Integer_Literal
|
|
and then Nkind (R) = N_Integer_Literal
|
|
and then Intval (L) = Intval (R))
|
|
|
|
or else
|
|
(Is_Entity_Name (L)
|
|
and then Ekind (Entity (L)) = E_Constant
|
|
and then ((Is_Entity_Name (R)
|
|
and then Entity (L) = Entity (R))
|
|
or else
|
|
(Nkind (R) = N_Type_Conversion
|
|
and then Is_Entity_Name (Expression (R))
|
|
and then Entity (L) = Entity (Expression (R)))))
|
|
|
|
or else
|
|
(Is_Entity_Name (R)
|
|
and then Ekind (Entity (R)) = E_Constant
|
|
and then Nkind (L) = N_Type_Conversion
|
|
and then Is_Entity_Name (Expression (L))
|
|
and then Entity (R) = Entity (Expression (L)))
|
|
|
|
or else
|
|
(Is_Entity_Name (L)
|
|
and then Is_Entity_Name (R)
|
|
and then Entity (L) = Entity (R)
|
|
and then Ekind (Entity (L)) = E_In_Parameter
|
|
and then Inside_Init_Proc);
|
|
end Same_Bounds;
|
|
|
|
-- Start of processing for Selected_Length_Checks
|
|
|
|
begin
|
|
if not Expander_Active then
|
|
return Ret_Result;
|
|
end if;
|
|
|
|
if Target_Typ = Any_Type
|
|
or else Target_Typ = Any_Composite
|
|
or else Raises_Constraint_Error (Ck_Node)
|
|
then
|
|
return Ret_Result;
|
|
end if;
|
|
|
|
if No (Wnode) then
|
|
Wnode := Ck_Node;
|
|
end if;
|
|
|
|
T_Typ := Target_Typ;
|
|
|
|
if No (Source_Typ) then
|
|
S_Typ := Etype (Ck_Node);
|
|
else
|
|
S_Typ := Source_Typ;
|
|
end if;
|
|
|
|
if S_Typ = Any_Type or else S_Typ = Any_Composite then
|
|
return Ret_Result;
|
|
end if;
|
|
|
|
if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then
|
|
S_Typ := Designated_Type (S_Typ);
|
|
T_Typ := Designated_Type (T_Typ);
|
|
Do_Access := True;
|
|
|
|
-- A simple optimization for the null case
|
|
|
|
if Known_Null (Ck_Node) then
|
|
return Ret_Result;
|
|
end if;
|
|
end if;
|
|
|
|
if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then
|
|
if Is_Constrained (T_Typ) then
|
|
|
|
-- The checking code to be generated will freeze the corresponding
|
|
-- array type. However, we must freeze the type now, so that the
|
|
-- freeze node does not appear within the generated if expression,
|
|
-- but ahead of it.
|
|
|
|
Freeze_Before (Ck_Node, T_Typ);
|
|
|
|
Expr_Actual := Get_Referenced_Object (Ck_Node);
|
|
Exptyp := Get_Actual_Subtype (Ck_Node);
|
|
|
|
if Is_Access_Type (Exptyp) then
|
|
Exptyp := Designated_Type (Exptyp);
|
|
end if;
|
|
|
|
-- String_Literal case. This needs to be handled specially be-
|
|
-- cause no index types are available for string literals. The
|
|
-- condition is simply:
|
|
|
|
-- T_Typ'Length = string-literal-length
|
|
|
|
if Nkind (Expr_Actual) = N_String_Literal
|
|
and then Ekind (Etype (Expr_Actual)) = E_String_Literal_Subtype
|
|
then
|
|
Cond :=
|
|
Make_Op_Ne (Loc,
|
|
Left_Opnd => Get_E_Length (T_Typ, 1),
|
|
Right_Opnd =>
|
|
Make_Integer_Literal (Loc,
|
|
Intval =>
|
|
String_Literal_Length (Etype (Expr_Actual))));
|
|
|
|
-- General array case. Here we have a usable actual subtype for
|
|
-- the expression, and the condition is built from the two types
|
|
-- (Do_Length):
|
|
|
|
-- T_Typ'Length /= Exptyp'Length or else
|
|
-- T_Typ'Length (2) /= Exptyp'Length (2) or else
|
|
-- T_Typ'Length (3) /= Exptyp'Length (3) or else
|
|
-- ...
|
|
|
|
elsif Is_Constrained (Exptyp) then
|
|
declare
|
|
Ndims : constant Nat := Number_Dimensions (T_Typ);
|
|
|
|
L_Index : Node_Id;
|
|
R_Index : Node_Id;
|
|
L_Low : Node_Id;
|
|
L_High : Node_Id;
|
|
R_Low : Node_Id;
|
|
R_High : Node_Id;
|
|
L_Length : Uint;
|
|
R_Length : Uint;
|
|
Ref_Node : Node_Id;
|
|
|
|
begin
|
|
-- At the library level, we need to ensure that the type of
|
|
-- the object is elaborated before the check itself is
|
|
-- emitted. This is only done if the object is in the
|
|
-- current compilation unit, otherwise the type is frozen
|
|
-- and elaborated in its unit.
|
|
|
|
if Is_Itype (Exptyp)
|
|
and then
|
|
Ekind (Cunit_Entity (Current_Sem_Unit)) = E_Package
|
|
and then
|
|
not In_Package_Body (Cunit_Entity (Current_Sem_Unit))
|
|
and then In_Open_Scopes (Scope (Exptyp))
|
|
then
|
|
Ref_Node := Make_Itype_Reference (Sloc (Ck_Node));
|
|
Set_Itype (Ref_Node, Exptyp);
|
|
Insert_Action (Ck_Node, Ref_Node);
|
|
end if;
|
|
|
|
L_Index := First_Index (T_Typ);
|
|
R_Index := First_Index (Exptyp);
|
|
|
|
for Indx in 1 .. Ndims loop
|
|
if not (Nkind (L_Index) = N_Raise_Constraint_Error
|
|
or else
|
|
Nkind (R_Index) = N_Raise_Constraint_Error)
|
|
then
|
|
Get_Index_Bounds (L_Index, L_Low, L_High);
|
|
Get_Index_Bounds (R_Index, R_Low, R_High);
|
|
|
|
-- Deal with compile time length check. Note that we
|
|
-- skip this in the access case, because the access
|
|
-- value may be null, so we cannot know statically.
|
|
|
|
if not Do_Access
|
|
and then Compile_Time_Known_Value (L_Low)
|
|
and then Compile_Time_Known_Value (L_High)
|
|
and then Compile_Time_Known_Value (R_Low)
|
|
and then Compile_Time_Known_Value (R_High)
|
|
then
|
|
if Expr_Value (L_High) >= Expr_Value (L_Low) then
|
|
L_Length := Expr_Value (L_High) -
|
|
Expr_Value (L_Low) + 1;
|
|
else
|
|
L_Length := UI_From_Int (0);
|
|
end if;
|
|
|
|
if Expr_Value (R_High) >= Expr_Value (R_Low) then
|
|
R_Length := Expr_Value (R_High) -
|
|
Expr_Value (R_Low) + 1;
|
|
else
|
|
R_Length := UI_From_Int (0);
|
|
end if;
|
|
|
|
if L_Length > R_Length then
|
|
Add_Check
|
|
(Compile_Time_Constraint_Error
|
|
(Wnode, "too few elements for}??", T_Typ));
|
|
|
|
elsif L_Length < R_Length then
|
|
Add_Check
|
|
(Compile_Time_Constraint_Error
|
|
(Wnode, "too many elements for}??", T_Typ));
|
|
end if;
|
|
|
|
-- The comparison for an individual index subtype
|
|
-- is omitted if the corresponding index subtypes
|
|
-- statically match, since the result is known to
|
|
-- be true. Note that this test is worth while even
|
|
-- though we do static evaluation, because non-static
|
|
-- subtypes can statically match.
|
|
|
|
elsif not
|
|
Subtypes_Statically_Match
|
|
(Etype (L_Index), Etype (R_Index))
|
|
|
|
and then not
|
|
(Same_Bounds (L_Low, R_Low)
|
|
and then Same_Bounds (L_High, R_High))
|
|
then
|
|
Evolve_Or_Else
|
|
(Cond, Length_E_Cond (Exptyp, T_Typ, Indx));
|
|
end if;
|
|
|
|
Next (L_Index);
|
|
Next (R_Index);
|
|
end if;
|
|
end loop;
|
|
end;
|
|
|
|
-- Handle cases where we do not get a usable actual subtype that
|
|
-- is constrained. This happens for example in the function call
|
|
-- and explicit dereference cases. In these cases, we have to get
|
|
-- the length or range from the expression itself, making sure we
|
|
-- do not evaluate it more than once.
|
|
|
|
-- Here Ck_Node is the original expression, or more properly the
|
|
-- result of applying Duplicate_Expr to the original tree, forcing
|
|
-- the result to be a name.
|
|
|
|
else
|
|
declare
|
|
Ndims : constant Nat := Number_Dimensions (T_Typ);
|
|
|
|
begin
|
|
-- Build the condition for the explicit dereference case
|
|
|
|
for Indx in 1 .. Ndims loop
|
|
Evolve_Or_Else
|
|
(Cond, Length_N_Cond (Ck_Node, T_Typ, Indx));
|
|
end loop;
|
|
end;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
|
|
-- Construct the test and insert into the tree
|
|
|
|
if Present (Cond) then
|
|
if Do_Access then
|
|
Cond := Guard_Access (Cond, Loc, Ck_Node);
|
|
end if;
|
|
|
|
Add_Check
|
|
(Make_Raise_Constraint_Error (Loc,
|
|
Condition => Cond,
|
|
Reason => CE_Length_Check_Failed));
|
|
end if;
|
|
|
|
return Ret_Result;
|
|
end Selected_Length_Checks;
|
|
|
|
---------------------------
|
|
-- Selected_Range_Checks --
|
|
---------------------------
|
|
|
|
function Selected_Range_Checks
|
|
(Ck_Node : Node_Id;
|
|
Target_Typ : Entity_Id;
|
|
Source_Typ : Entity_Id;
|
|
Warn_Node : Node_Id) return Check_Result
|
|
is
|
|
Loc : constant Source_Ptr := Sloc (Ck_Node);
|
|
S_Typ : Entity_Id;
|
|
T_Typ : Entity_Id;
|
|
Expr_Actual : Node_Id;
|
|
Exptyp : Entity_Id;
|
|
Cond : Node_Id := Empty;
|
|
Do_Access : Boolean := False;
|
|
Wnode : Node_Id := Warn_Node;
|
|
Ret_Result : Check_Result := (Empty, Empty);
|
|
Num_Checks : Integer := 0;
|
|
|
|
procedure Add_Check (N : Node_Id);
|
|
-- Adds the action given to Ret_Result if N is non-Empty
|
|
|
|
function Discrete_Range_Cond
|
|
(Expr : Node_Id;
|
|
Typ : Entity_Id) return Node_Id;
|
|
-- Returns expression to compute:
|
|
-- Low_Bound (Expr) < Typ'First
|
|
-- or else
|
|
-- High_Bound (Expr) > Typ'Last
|
|
|
|
function Discrete_Expr_Cond
|
|
(Expr : Node_Id;
|
|
Typ : Entity_Id) return Node_Id;
|
|
-- Returns expression to compute:
|
|
-- Expr < Typ'First
|
|
-- or else
|
|
-- Expr > Typ'Last
|
|
|
|
function Get_E_First_Or_Last
|
|
(Loc : Source_Ptr;
|
|
E : Entity_Id;
|
|
Indx : Nat;
|
|
Nam : Name_Id) return Node_Id;
|
|
-- Returns an attribute reference
|
|
-- E'First or E'Last
|
|
-- with a source location of Loc.
|
|
--
|
|
-- Nam is Name_First or Name_Last, according to which attribute is
|
|
-- desired. If Indx is non-zero, it is passed as a literal in the
|
|
-- Expressions of the attribute reference (identifying the desired
|
|
-- array dimension).
|
|
|
|
function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id;
|
|
function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id;
|
|
-- Returns expression to compute:
|
|
-- N'First or N'Last using Duplicate_Subexpr_No_Checks
|
|
|
|
function Range_E_Cond
|
|
(Exptyp : Entity_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat)
|
|
return Node_Id;
|
|
-- Returns expression to compute:
|
|
-- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last
|
|
|
|
function Range_Equal_E_Cond
|
|
(Exptyp : Entity_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat) return Node_Id;
|
|
-- Returns expression to compute:
|
|
-- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last
|
|
|
|
function Range_N_Cond
|
|
(Expr : Node_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat) return Node_Id;
|
|
-- Return expression to compute:
|
|
-- Expr'First < Typ'First or else Expr'Last > Typ'Last
|
|
|
|
---------------
|
|
-- Add_Check --
|
|
---------------
|
|
|
|
procedure Add_Check (N : Node_Id) is
|
|
begin
|
|
if Present (N) then
|
|
|
|
-- For now, ignore attempt to place more than 2 checks ???
|
|
|
|
if Num_Checks = 2 then
|
|
return;
|
|
end if;
|
|
|
|
pragma Assert (Num_Checks <= 1);
|
|
Num_Checks := Num_Checks + 1;
|
|
Ret_Result (Num_Checks) := N;
|
|
end if;
|
|
end Add_Check;
|
|
|
|
-------------------------
|
|
-- Discrete_Expr_Cond --
|
|
-------------------------
|
|
|
|
function Discrete_Expr_Cond
|
|
(Expr : Node_Id;
|
|
Typ : Entity_Id) return Node_Id
|
|
is
|
|
begin
|
|
return
|
|
Make_Or_Else (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Lt (Loc,
|
|
Left_Opnd =>
|
|
Convert_To (Base_Type (Typ),
|
|
Duplicate_Subexpr_No_Checks (Expr)),
|
|
Right_Opnd =>
|
|
Convert_To (Base_Type (Typ),
|
|
Get_E_First_Or_Last (Loc, Typ, 0, Name_First))),
|
|
|
|
Right_Opnd =>
|
|
Make_Op_Gt (Loc,
|
|
Left_Opnd =>
|
|
Convert_To (Base_Type (Typ),
|
|
Duplicate_Subexpr_No_Checks (Expr)),
|
|
Right_Opnd =>
|
|
Convert_To
|
|
(Base_Type (Typ),
|
|
Get_E_First_Or_Last (Loc, Typ, 0, Name_Last))));
|
|
end Discrete_Expr_Cond;
|
|
|
|
-------------------------
|
|
-- Discrete_Range_Cond --
|
|
-------------------------
|
|
|
|
function Discrete_Range_Cond
|
|
(Expr : Node_Id;
|
|
Typ : Entity_Id) return Node_Id
|
|
is
|
|
LB : Node_Id := Low_Bound (Expr);
|
|
HB : Node_Id := High_Bound (Expr);
|
|
|
|
Left_Opnd : Node_Id;
|
|
Right_Opnd : Node_Id;
|
|
|
|
begin
|
|
if Nkind (LB) = N_Identifier
|
|
and then Ekind (Entity (LB)) = E_Discriminant
|
|
then
|
|
LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc);
|
|
end if;
|
|
|
|
Left_Opnd :=
|
|
Make_Op_Lt (Loc,
|
|
Left_Opnd =>
|
|
Convert_To
|
|
(Base_Type (Typ), Duplicate_Subexpr_No_Checks (LB)),
|
|
|
|
Right_Opnd =>
|
|
Convert_To
|
|
(Base_Type (Typ),
|
|
Get_E_First_Or_Last (Loc, Typ, 0, Name_First)));
|
|
|
|
if Nkind (HB) = N_Identifier
|
|
and then Ekind (Entity (HB)) = E_Discriminant
|
|
then
|
|
HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc);
|
|
end if;
|
|
|
|
Right_Opnd :=
|
|
Make_Op_Gt (Loc,
|
|
Left_Opnd =>
|
|
Convert_To
|
|
(Base_Type (Typ), Duplicate_Subexpr_No_Checks (HB)),
|
|
|
|
Right_Opnd =>
|
|
Convert_To
|
|
(Base_Type (Typ),
|
|
Get_E_First_Or_Last (Loc, Typ, 0, Name_Last)));
|
|
|
|
return Make_Or_Else (Loc, Left_Opnd, Right_Opnd);
|
|
end Discrete_Range_Cond;
|
|
|
|
-------------------------
|
|
-- Get_E_First_Or_Last --
|
|
-------------------------
|
|
|
|
function Get_E_First_Or_Last
|
|
(Loc : Source_Ptr;
|
|
E : Entity_Id;
|
|
Indx : Nat;
|
|
Nam : Name_Id) return Node_Id
|
|
is
|
|
Exprs : List_Id;
|
|
begin
|
|
if Indx > 0 then
|
|
Exprs := New_List (Make_Integer_Literal (Loc, UI_From_Int (Indx)));
|
|
else
|
|
Exprs := No_List;
|
|
end if;
|
|
|
|
return Make_Attribute_Reference (Loc,
|
|
Prefix => New_Occurrence_Of (E, Loc),
|
|
Attribute_Name => Nam,
|
|
Expressions => Exprs);
|
|
end Get_E_First_Or_Last;
|
|
|
|
-----------------
|
|
-- Get_N_First --
|
|
-----------------
|
|
|
|
function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is
|
|
begin
|
|
return
|
|
Make_Attribute_Reference (Loc,
|
|
Attribute_Name => Name_First,
|
|
Prefix =>
|
|
Duplicate_Subexpr_No_Checks (N, Name_Req => True),
|
|
Expressions => New_List (
|
|
Make_Integer_Literal (Loc, Indx)));
|
|
end Get_N_First;
|
|
|
|
----------------
|
|
-- Get_N_Last --
|
|
----------------
|
|
|
|
function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is
|
|
begin
|
|
return
|
|
Make_Attribute_Reference (Loc,
|
|
Attribute_Name => Name_Last,
|
|
Prefix =>
|
|
Duplicate_Subexpr_No_Checks (N, Name_Req => True),
|
|
Expressions => New_List (
|
|
Make_Integer_Literal (Loc, Indx)));
|
|
end Get_N_Last;
|
|
|
|
------------------
|
|
-- Range_E_Cond --
|
|
------------------
|
|
|
|
function Range_E_Cond
|
|
(Exptyp : Entity_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat) return Node_Id
|
|
is
|
|
begin
|
|
return
|
|
Make_Or_Else (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Lt (Loc,
|
|
Left_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First),
|
|
Right_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)),
|
|
|
|
Right_Opnd =>
|
|
Make_Op_Gt (Loc,
|
|
Left_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last),
|
|
Right_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last)));
|
|
end Range_E_Cond;
|
|
|
|
------------------------
|
|
-- Range_Equal_E_Cond --
|
|
------------------------
|
|
|
|
function Range_Equal_E_Cond
|
|
(Exptyp : Entity_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat) return Node_Id
|
|
is
|
|
begin
|
|
return
|
|
Make_Or_Else (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Ne (Loc,
|
|
Left_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_First),
|
|
Right_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)),
|
|
|
|
Right_Opnd =>
|
|
Make_Op_Ne (Loc,
|
|
Left_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Exptyp, Indx, Name_Last),
|
|
Right_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last)));
|
|
end Range_Equal_E_Cond;
|
|
|
|
------------------
|
|
-- Range_N_Cond --
|
|
------------------
|
|
|
|
function Range_N_Cond
|
|
(Expr : Node_Id;
|
|
Typ : Entity_Id;
|
|
Indx : Nat) return Node_Id
|
|
is
|
|
begin
|
|
return
|
|
Make_Or_Else (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Lt (Loc,
|
|
Left_Opnd =>
|
|
Get_N_First (Expr, Indx),
|
|
Right_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Typ, Indx, Name_First)),
|
|
|
|
Right_Opnd =>
|
|
Make_Op_Gt (Loc,
|
|
Left_Opnd =>
|
|
Get_N_Last (Expr, Indx),
|
|
Right_Opnd =>
|
|
Get_E_First_Or_Last (Loc, Typ, Indx, Name_Last)));
|
|
end Range_N_Cond;
|
|
|
|
-- Start of processing for Selected_Range_Checks
|
|
|
|
begin
|
|
if not Expander_Active then
|
|
return Ret_Result;
|
|
end if;
|
|
|
|
if Target_Typ = Any_Type
|
|
or else Target_Typ = Any_Composite
|
|
or else Raises_Constraint_Error (Ck_Node)
|
|
then
|
|
return Ret_Result;
|
|
end if;
|
|
|
|
if No (Wnode) then
|
|
Wnode := Ck_Node;
|
|
end if;
|
|
|
|
T_Typ := Target_Typ;
|
|
|
|
if No (Source_Typ) then
|
|
S_Typ := Etype (Ck_Node);
|
|
else
|
|
S_Typ := Source_Typ;
|
|
end if;
|
|
|
|
if S_Typ = Any_Type or else S_Typ = Any_Composite then
|
|
return Ret_Result;
|
|
end if;
|
|
|
|
-- The order of evaluating T_Typ before S_Typ seems to be critical
|
|
-- because S_Typ can be derived from Etype (Ck_Node), if it's not passed
|
|
-- in, and since Node can be an N_Range node, it might be invalid.
|
|
-- Should there be an assert check somewhere for taking the Etype of
|
|
-- an N_Range node ???
|
|
|
|
if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then
|
|
S_Typ := Designated_Type (S_Typ);
|
|
T_Typ := Designated_Type (T_Typ);
|
|
Do_Access := True;
|
|
|
|
-- A simple optimization for the null case
|
|
|
|
if Known_Null (Ck_Node) then
|
|
return Ret_Result;
|
|
end if;
|
|
end if;
|
|
|
|
-- For an N_Range Node, check for a null range and then if not
|
|
-- null generate a range check action.
|
|
|
|
if Nkind (Ck_Node) = N_Range then
|
|
|
|
-- There's no point in checking a range against itself
|
|
|
|
if Ck_Node = Scalar_Range (T_Typ) then
|
|
return Ret_Result;
|
|
end if;
|
|
|
|
declare
|
|
T_LB : constant Node_Id := Type_Low_Bound (T_Typ);
|
|
T_HB : constant Node_Id := Type_High_Bound (T_Typ);
|
|
Known_T_LB : constant Boolean := Compile_Time_Known_Value (T_LB);
|
|
Known_T_HB : constant Boolean := Compile_Time_Known_Value (T_HB);
|
|
|
|
LB : Node_Id := Low_Bound (Ck_Node);
|
|
HB : Node_Id := High_Bound (Ck_Node);
|
|
Known_LB : Boolean := False;
|
|
Known_HB : Boolean := False;
|
|
|
|
Null_Range : Boolean;
|
|
Out_Of_Range_L : Boolean;
|
|
Out_Of_Range_H : Boolean;
|
|
|
|
begin
|
|
-- Compute what is known at compile time
|
|
|
|
if Known_T_LB and Known_T_HB then
|
|
if Compile_Time_Known_Value (LB) then
|
|
Known_LB := True;
|
|
|
|
-- There's no point in checking that a bound is within its
|
|
-- own range so pretend that it is known in this case. First
|
|
-- deal with low bound.
|
|
|
|
elsif Ekind (Etype (LB)) = E_Signed_Integer_Subtype
|
|
and then Scalar_Range (Etype (LB)) = Scalar_Range (T_Typ)
|
|
then
|
|
LB := T_LB;
|
|
Known_LB := True;
|
|
end if;
|
|
|
|
-- Likewise for the high bound
|
|
|
|
if Compile_Time_Known_Value (HB) then
|
|
Known_HB := True;
|
|
|
|
elsif Ekind (Etype (HB)) = E_Signed_Integer_Subtype
|
|
and then Scalar_Range (Etype (HB)) = Scalar_Range (T_Typ)
|
|
then
|
|
HB := T_HB;
|
|
Known_HB := True;
|
|
end if;
|
|
end if;
|
|
|
|
-- Check for case where everything is static and we can do the
|
|
-- check at compile time. This is skipped if we have an access
|
|
-- type, since the access value may be null.
|
|
|
|
-- ??? This code can be improved since you only need to know that
|
|
-- the two respective bounds (LB & T_LB or HB & T_HB) are known at
|
|
-- compile time to emit pertinent messages.
|
|
|
|
if Known_T_LB and Known_T_HB and Known_LB and Known_HB
|
|
and not Do_Access
|
|
then
|
|
-- Floating-point case
|
|
|
|
if Is_Floating_Point_Type (S_Typ) then
|
|
Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB);
|
|
Out_Of_Range_L :=
|
|
(Expr_Value_R (LB) < Expr_Value_R (T_LB))
|
|
or else
|
|
(Expr_Value_R (LB) > Expr_Value_R (T_HB));
|
|
|
|
Out_Of_Range_H :=
|
|
(Expr_Value_R (HB) > Expr_Value_R (T_HB))
|
|
or else
|
|
(Expr_Value_R (HB) < Expr_Value_R (T_LB));
|
|
|
|
-- Fixed or discrete type case
|
|
|
|
else
|
|
Null_Range := Expr_Value (HB) < Expr_Value (LB);
|
|
Out_Of_Range_L :=
|
|
(Expr_Value (LB) < Expr_Value (T_LB))
|
|
or else
|
|
(Expr_Value (LB) > Expr_Value (T_HB));
|
|
|
|
Out_Of_Range_H :=
|
|
(Expr_Value (HB) > Expr_Value (T_HB))
|
|
or else
|
|
(Expr_Value (HB) < Expr_Value (T_LB));
|
|
end if;
|
|
|
|
if not Null_Range then
|
|
if Out_Of_Range_L then
|
|
if No (Warn_Node) then
|
|
Add_Check
|
|
(Compile_Time_Constraint_Error
|
|
(Low_Bound (Ck_Node),
|
|
"static value out of range of}??", T_Typ));
|
|
|
|
else
|
|
Add_Check
|
|
(Compile_Time_Constraint_Error
|
|
(Wnode,
|
|
"static range out of bounds of}??", T_Typ));
|
|
end if;
|
|
end if;
|
|
|
|
if Out_Of_Range_H then
|
|
if No (Warn_Node) then
|
|
Add_Check
|
|
(Compile_Time_Constraint_Error
|
|
(High_Bound (Ck_Node),
|
|
"static value out of range of}??", T_Typ));
|
|
|
|
else
|
|
Add_Check
|
|
(Compile_Time_Constraint_Error
|
|
(Wnode,
|
|
"static range out of bounds of}??", T_Typ));
|
|
end if;
|
|
end if;
|
|
end if;
|
|
|
|
else
|
|
declare
|
|
LB : Node_Id := Low_Bound (Ck_Node);
|
|
HB : Node_Id := High_Bound (Ck_Node);
|
|
|
|
begin
|
|
-- If either bound is a discriminant and we are within the
|
|
-- record declaration, it is a use of the discriminant in a
|
|
-- constraint of a component, and nothing can be checked
|
|
-- here. The check will be emitted within the init proc.
|
|
-- Before then, the discriminal has no real meaning.
|
|
-- Similarly, if the entity is a discriminal, there is no
|
|
-- check to perform yet.
|
|
|
|
-- The same holds within a discriminated synchronized type,
|
|
-- where the discriminant may constrain a component or an
|
|
-- entry family.
|
|
|
|
if Nkind (LB) = N_Identifier
|
|
and then Denotes_Discriminant (LB, True)
|
|
then
|
|
if Current_Scope = Scope (Entity (LB))
|
|
or else Is_Concurrent_Type (Current_Scope)
|
|
or else Ekind (Entity (LB)) /= E_Discriminant
|
|
then
|
|
return Ret_Result;
|
|
else
|
|
LB :=
|
|
New_Occurrence_Of (Discriminal (Entity (LB)), Loc);
|
|
end if;
|
|
end if;
|
|
|
|
if Nkind (HB) = N_Identifier
|
|
and then Denotes_Discriminant (HB, True)
|
|
then
|
|
if Current_Scope = Scope (Entity (HB))
|
|
or else Is_Concurrent_Type (Current_Scope)
|
|
or else Ekind (Entity (HB)) /= E_Discriminant
|
|
then
|
|
return Ret_Result;
|
|
else
|
|
HB :=
|
|
New_Occurrence_Of (Discriminal (Entity (HB)), Loc);
|
|
end if;
|
|
end if;
|
|
|
|
Cond := Discrete_Range_Cond (Ck_Node, T_Typ);
|
|
Set_Paren_Count (Cond, 1);
|
|
|
|
Cond :=
|
|
Make_And_Then (Loc,
|
|
Left_Opnd =>
|
|
Make_Op_Ge (Loc,
|
|
Left_Opnd =>
|
|
Convert_To (Base_Type (Etype (HB)),
|
|
Duplicate_Subexpr_No_Checks (HB)),
|
|
Right_Opnd =>
|
|
Convert_To (Base_Type (Etype (LB)),
|
|
Duplicate_Subexpr_No_Checks (LB))),
|
|
Right_Opnd => Cond);
|
|
end;
|
|
end if;
|
|
end;
|
|
|
|
elsif Is_Scalar_Type (S_Typ) then
|
|
|
|
-- This somewhat duplicates what Apply_Scalar_Range_Check does,
|
|
-- except the above simply sets a flag in the node and lets
|
|
-- gigi generate the check base on the Etype of the expression.
|
|
-- Sometimes, however we want to do a dynamic check against an
|
|
-- arbitrary target type, so we do that here.
|
|
|
|
if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then
|
|
Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
|
|
|
|
-- For literals, we can tell if the constraint error will be
|
|
-- raised at compile time, so we never need a dynamic check, but
|
|
-- if the exception will be raised, then post the usual warning,
|
|
-- and replace the literal with a raise constraint error
|
|
-- expression. As usual, skip this for access types
|
|
|
|
elsif Compile_Time_Known_Value (Ck_Node) and then not Do_Access then
|
|
declare
|
|
LB : constant Node_Id := Type_Low_Bound (T_Typ);
|
|
UB : constant Node_Id := Type_High_Bound (T_Typ);
|
|
|
|
Out_Of_Range : Boolean;
|
|
Static_Bounds : constant Boolean :=
|
|
Compile_Time_Known_Value (LB)
|
|
and Compile_Time_Known_Value (UB);
|
|
|
|
begin
|
|
-- Following range tests should use Sem_Eval routine ???
|
|
|
|
if Static_Bounds then
|
|
if Is_Floating_Point_Type (S_Typ) then
|
|
Out_Of_Range :=
|
|
(Expr_Value_R (Ck_Node) < Expr_Value_R (LB))
|
|
or else
|
|
(Expr_Value_R (Ck_Node) > Expr_Value_R (UB));
|
|
|
|
-- Fixed or discrete type
|
|
|
|
else
|
|
Out_Of_Range :=
|
|
Expr_Value (Ck_Node) < Expr_Value (LB)
|
|
or else
|
|
Expr_Value (Ck_Node) > Expr_Value (UB);
|
|
end if;
|
|
|
|
-- Bounds of the type are static and the literal is out of
|
|
-- range so output a warning message.
|
|
|
|
if Out_Of_Range then
|
|
if No (Warn_Node) then
|
|
Add_Check
|
|
(Compile_Time_Constraint_Error
|
|
(Ck_Node,
|
|
"static value out of range of}??", T_Typ));
|
|
|
|
else
|
|
Add_Check
|
|
(Compile_Time_Constraint_Error
|
|
(Wnode,
|
|
"static value out of range of}??", T_Typ));
|
|
end if;
|
|
end if;
|
|
|
|
else
|
|
Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
|
|
end if;
|
|
end;
|
|
|
|
-- Here for the case of a non-static expression, we need a runtime
|
|
-- check unless the source type range is guaranteed to be in the
|
|
-- range of the target type.
|
|
|
|
else
|
|
if not In_Subrange_Of (S_Typ, T_Typ) then
|
|
Cond := Discrete_Expr_Cond (Ck_Node, T_Typ);
|
|
end if;
|
|
end if;
|
|
end if;
|
|
|
|
if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then
|
|
if Is_Constrained (T_Typ) then
|
|
|
|
Expr_Actual := Get_Referenced_Object (Ck_Node);
|
|
Exptyp := Get_Actual_Subtype (Expr_Actual);
|
|
|
|
if Is_Access_Type (Exptyp) then
|
|
Exptyp := Designated_Type (Exptyp);
|
|
end if;
|
|
|
|
-- String_Literal case. This needs to be handled specially be-
|
|
-- cause no index types are available for string literals. The
|
|
-- condition is simply:
|
|
|
|
-- T_Typ'Length = string-literal-length
|
|
|
|
if Nkind (Expr_Actual) = N_String_Literal then
|
|
null;
|
|
|
|
-- General array case. Here we have a usable actual subtype for
|
|
-- the expression, and the condition is built from the two types
|
|
|
|
-- T_Typ'First < Exptyp'First or else
|
|
-- T_Typ'Last > Exptyp'Last or else
|
|
-- T_Typ'First(1) < Exptyp'First(1) or else
|
|
-- T_Typ'Last(1) > Exptyp'Last(1) or else
|
|
-- ...
|
|
|
|
elsif Is_Constrained (Exptyp) then
|
|
declare
|
|
Ndims : constant Nat := Number_Dimensions (T_Typ);
|
|
|
|
L_Index : Node_Id;
|
|
R_Index : Node_Id;
|
|
|
|
begin
|
|
L_Index := First_Index (T_Typ);
|
|
R_Index := First_Index (Exptyp);
|
|
|
|
for Indx in 1 .. Ndims loop
|
|
if not (Nkind (L_Index) = N_Raise_Constraint_Error
|
|
or else
|
|
Nkind (R_Index) = N_Raise_Constraint_Error)
|
|
then
|
|
-- Deal with compile time length check. Note that we
|
|
-- skip this in the access case, because the access
|
|
-- value may be null, so we cannot know statically.
|
|
|
|
if not
|
|
Subtypes_Statically_Match
|
|
(Etype (L_Index), Etype (R_Index))
|
|
then
|
|
-- If the target type is constrained then we
|
|
-- have to check for exact equality of bounds
|
|
-- (required for qualified expressions).
|
|
|
|
if Is_Constrained (T_Typ) then
|
|
Evolve_Or_Else
|
|
(Cond,
|
|
Range_Equal_E_Cond (Exptyp, T_Typ, Indx));
|
|
else
|
|
Evolve_Or_Else
|
|
(Cond, Range_E_Cond (Exptyp, T_Typ, Indx));
|
|
end if;
|
|
end if;
|
|
|
|
Next (L_Index);
|
|
Next (R_Index);
|
|
end if;
|
|
end loop;
|
|
end;
|
|
|
|
-- Handle cases where we do not get a usable actual subtype that
|
|
-- is constrained. This happens for example in the function call
|
|
-- and explicit dereference cases. In these cases, we have to get
|
|
-- the length or range from the expression itself, making sure we
|
|
-- do not evaluate it more than once.
|
|
|
|
-- Here Ck_Node is the original expression, or more properly the
|
|
-- result of applying Duplicate_Expr to the original tree,
|
|
-- forcing the result to be a name.
|
|
|
|
else
|
|
declare
|
|
Ndims : constant Nat := Number_Dimensions (T_Typ);
|
|
|
|
begin
|
|
-- Build the condition for the explicit dereference case
|
|
|
|
for Indx in 1 .. Ndims loop
|
|
Evolve_Or_Else
|
|
(Cond, Range_N_Cond (Ck_Node, T_Typ, Indx));
|
|
end loop;
|
|
end;
|
|
end if;
|
|
|
|
else
|
|
-- For a conversion to an unconstrained array type, generate an
|
|
-- Action to check that the bounds of the source value are within
|
|
-- the constraints imposed by the target type (RM 4.6(38)). No
|
|
-- check is needed for a conversion to an access to unconstrained
|
|
-- array type, as 4.6(24.15/2) requires the designated subtypes
|
|
-- of the two access types to statically match.
|
|
|
|
if Nkind (Parent (Ck_Node)) = N_Type_Conversion
|
|
and then not Do_Access
|
|
then
|
|
declare
|
|
Opnd_Index : Node_Id;
|
|
Targ_Index : Node_Id;
|
|
Opnd_Range : Node_Id;
|
|
|
|
begin
|
|
Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node));
|
|
Targ_Index := First_Index (T_Typ);
|
|
while Present (Opnd_Index) loop
|
|
|
|
-- If the index is a range, use its bounds. If it is an
|
|
-- entity (as will be the case if it is a named subtype
|
|
-- or an itype created for a slice) retrieve its range.
|
|
|
|
if Is_Entity_Name (Opnd_Index)
|
|
and then Is_Type (Entity (Opnd_Index))
|
|
then
|
|
Opnd_Range := Scalar_Range (Entity (Opnd_Index));
|
|
else
|
|
Opnd_Range := Opnd_Index;
|
|
end if;
|
|
|
|
if Nkind (Opnd_Range) = N_Range then
|
|
if Is_In_Range
|
|
(Low_Bound (Opnd_Range), Etype (Targ_Index),
|
|
Assume_Valid => True)
|
|
and then
|
|
Is_In_Range
|
|
(High_Bound (Opnd_Range), Etype (Targ_Index),
|
|
Assume_Valid => True)
|
|
then
|
|
null;
|
|
|
|
-- If null range, no check needed
|
|
|
|
elsif
|
|
Compile_Time_Known_Value (High_Bound (Opnd_Range))
|
|
and then
|
|
Compile_Time_Known_Value (Low_Bound (Opnd_Range))
|
|
and then
|
|
Expr_Value (High_Bound (Opnd_Range)) <
|
|
Expr_Value (Low_Bound (Opnd_Range))
|
|
then
|
|
null;
|
|
|
|
elsif Is_Out_Of_Range
|
|
(Low_Bound (Opnd_Range), Etype (Targ_Index),
|
|
Assume_Valid => True)
|
|
or else
|
|
Is_Out_Of_Range
|
|
(High_Bound (Opnd_Range), Etype (Targ_Index),
|
|
Assume_Valid => True)
|
|
then
|
|
Add_Check
|
|
(Compile_Time_Constraint_Error
|
|
(Wnode, "value out of range of}??", T_Typ));
|
|
|
|
else
|
|
Evolve_Or_Else
|
|
(Cond,
|
|
Discrete_Range_Cond
|
|
(Opnd_Range, Etype (Targ_Index)));
|
|
end if;
|
|
end if;
|
|
|
|
Next_Index (Opnd_Index);
|
|
Next_Index (Targ_Index);
|
|
end loop;
|
|
end;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
|
|
-- Construct the test and insert into the tree
|
|
|
|
if Present (Cond) then
|
|
if Do_Access then
|
|
Cond := Guard_Access (Cond, Loc, Ck_Node);
|
|
end if;
|
|
|
|
Add_Check
|
|
(Make_Raise_Constraint_Error (Loc,
|
|
Condition => Cond,
|
|
Reason => CE_Range_Check_Failed));
|
|
end if;
|
|
|
|
return Ret_Result;
|
|
end Selected_Range_Checks;
|
|
|
|
-------------------------------
|
|
-- Storage_Checks_Suppressed --
|
|
-------------------------------
|
|
|
|
function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) and then Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Storage_Check);
|
|
else
|
|
return Scope_Suppress.Suppress (Storage_Check);
|
|
end if;
|
|
end Storage_Checks_Suppressed;
|
|
|
|
---------------------------
|
|
-- Tag_Checks_Suppressed --
|
|
---------------------------
|
|
|
|
function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E)
|
|
and then Checks_May_Be_Suppressed (E)
|
|
then
|
|
return Is_Check_Suppressed (E, Tag_Check);
|
|
else
|
|
return Scope_Suppress.Suppress (Tag_Check);
|
|
end if;
|
|
end Tag_Checks_Suppressed;
|
|
|
|
---------------------------------------
|
|
-- Validate_Alignment_Check_Warnings --
|
|
---------------------------------------
|
|
|
|
procedure Validate_Alignment_Check_Warnings is
|
|
begin
|
|
for J in Alignment_Warnings.First .. Alignment_Warnings.Last loop
|
|
declare
|
|
AWR : Alignment_Warnings_Record
|
|
renames Alignment_Warnings.Table (J);
|
|
begin
|
|
if Known_Alignment (AWR.E)
|
|
and then AWR.A mod Alignment (AWR.E) = 0
|
|
then
|
|
Delete_Warning_And_Continuations (AWR.W);
|
|
end if;
|
|
end;
|
|
end loop;
|
|
end Validate_Alignment_Check_Warnings;
|
|
|
|
--------------------------
|
|
-- Validity_Check_Range --
|
|
--------------------------
|
|
|
|
procedure Validity_Check_Range
|
|
(N : Node_Id;
|
|
Related_Id : Entity_Id := Empty)
|
|
is
|
|
begin
|
|
if Validity_Checks_On and Validity_Check_Operands then
|
|
if Nkind (N) = N_Range then
|
|
Ensure_Valid
|
|
(Expr => Low_Bound (N),
|
|
Related_Id => Related_Id,
|
|
Is_Low_Bound => True);
|
|
|
|
Ensure_Valid
|
|
(Expr => High_Bound (N),
|
|
Related_Id => Related_Id,
|
|
Is_High_Bound => True);
|
|
end if;
|
|
end if;
|
|
end Validity_Check_Range;
|
|
|
|
--------------------------------
|
|
-- Validity_Checks_Suppressed --
|
|
--------------------------------
|
|
|
|
function Validity_Checks_Suppressed (E : Entity_Id) return Boolean is
|
|
begin
|
|
if Present (E) and then Checks_May_Be_Suppressed (E) then
|
|
return Is_Check_Suppressed (E, Validity_Check);
|
|
else
|
|
return Scope_Suppress.Suppress (Validity_Check);
|
|
end if;
|
|
end Validity_Checks_Suppressed;
|
|
|
|
end Checks;
|