4350 lines
138 KiB
Ada
4350 lines
138 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S E M _ E V A L --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2004 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 2, 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 COPYING. If not, write --
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-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
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-- MA 02111-1307, USA. --
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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 Checks; use Checks;
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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 Errout; use Errout;
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with Eval_Fat; use Eval_Fat;
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with Exp_Util; use Exp_Util;
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with Nmake; use Nmake;
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with Nlists; use Nlists;
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with Opt; use Opt;
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with Sem; use Sem;
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with Sem_Cat; use Sem_Cat;
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with Sem_Ch8; use Sem_Ch8;
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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_Type; use Sem_Type;
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with Sem_Warn; use Sem_Warn;
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with Sinfo; use Sinfo;
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with Snames; use Snames;
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with Stand; use Stand;
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with Stringt; use Stringt;
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with Tbuild; use Tbuild;
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package body Sem_Eval is
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-----------------------------------------
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-- Handling of Compile Time Evaluation --
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-----------------------------------------
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-- The compile time evaluation of expressions is distributed over several
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-- Eval_xxx procedures. These procedures are called immediatedly after
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-- a subexpression is resolved and is therefore accomplished in a bottom
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-- up fashion. The flags are synthesized using the following approach.
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-- Is_Static_Expression is determined by following the detailed rules
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-- in RM 4.9(4-14). This involves testing the Is_Static_Expression
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-- flag of the operands in many cases.
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-- Raises_Constraint_Error is set if any of the operands have the flag
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-- set or if an attempt to compute the value of the current expression
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-- results in detection of a runtime constraint error.
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-- As described in the spec, the requirement is that Is_Static_Expression
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-- be accurately set, and in addition for nodes for which this flag is set,
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-- Raises_Constraint_Error must also be set. Furthermore a node which has
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-- Is_Static_Expression set, and Raises_Constraint_Error clear, then the
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-- requirement is that the expression value must be precomputed, and the
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-- node is either a literal, or the name of a constant entity whose value
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-- is a static expression.
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-- The general approach is as follows. First compute Is_Static_Expression.
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-- If the node is not static, then the flag is left off in the node and
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-- we are all done. Otherwise for a static node, we test if any of the
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-- operands will raise constraint error, and if so, propagate the flag
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-- Raises_Constraint_Error to the result node and we are done (since the
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-- error was already posted at a lower level).
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-- For the case of a static node whose operands do not raise constraint
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-- error, we attempt to evaluate the node. If this evaluation succeeds,
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-- then the node is replaced by the result of this computation. If the
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-- evaluation raises constraint error, then we rewrite the node with
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-- Apply_Compile_Time_Constraint_Error to raise the exception and also
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-- to post appropriate error messages.
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----------------
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-- Local Data --
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----------------
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type Bits is array (Nat range <>) of Boolean;
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-- Used to convert unsigned (modular) values for folding logical ops
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-- The following definitions are used to maintain a cache of nodes that
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-- have compile time known values. The cache is maintained only for
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-- discrete types (the most common case), and is populated by calls to
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-- Compile_Time_Known_Value and Expr_Value, but only used by Expr_Value
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-- since it is possible for the status to change (in particular it is
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-- possible for a node to get replaced by a constraint error node).
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CV_Bits : constant := 5;
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-- Number of low order bits of Node_Id value used to reference entries
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-- in the cache table.
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CV_Cache_Size : constant Nat := 2 ** CV_Bits;
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-- Size of cache for compile time values
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subtype CV_Range is Nat range 0 .. CV_Cache_Size;
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type CV_Entry is record
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N : Node_Id;
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V : Uint;
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end record;
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type CV_Cache_Array is array (CV_Range) of CV_Entry;
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CV_Cache : CV_Cache_Array := (others => (Node_High_Bound, Uint_0));
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-- This is the actual cache, with entries consisting of node/value pairs,
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-- and the impossible value Node_High_Bound used for unset entries.
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-----------------------
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-- Local Subprograms --
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-----------------------
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function From_Bits (B : Bits; T : Entity_Id) return Uint;
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-- Converts a bit string of length B'Length to a Uint value to be used
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-- for a target of type T, which is a modular type. This procedure
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-- includes the necessary reduction by the modulus in the case of a
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-- non-binary modulus (for a binary modulus, the bit string is the
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-- right length any way so all is well).
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function Get_String_Val (N : Node_Id) return Node_Id;
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-- Given a tree node for a folded string or character value, returns
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-- the corresponding string literal or character literal (one of the
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-- two must be available, or the operand would not have been marked
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-- as foldable in the earlier analysis of the operation).
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function OK_Bits (N : Node_Id; Bits : Uint) return Boolean;
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-- Bits represents the number of bits in an integer value to be computed
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-- (but the value has not been computed yet). If this value in Bits is
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-- reasonable, a result of True is returned, with the implication that
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-- the caller should go ahead and complete the calculation. If the value
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-- in Bits is unreasonably large, then an error is posted on node N, and
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-- False is returned (and the caller skips the proposed calculation).
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procedure Out_Of_Range (N : Node_Id);
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-- This procedure is called if it is determined that node N, which
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-- appears in a non-static context, is a compile time known value
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-- which is outside its range, i.e. the range of Etype. This is used
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-- in contexts where this is an illegality if N is static, and should
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-- generate a warning otherwise.
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procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id);
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-- N and Exp are nodes representing an expression, Exp is known
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-- to raise CE. N is rewritten in term of Exp in the optimal way.
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function String_Type_Len (Stype : Entity_Id) return Uint;
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-- Given a string type, determines the length of the index type, or,
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-- if this index type is non-static, the length of the base type of
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-- this index type. Note that if the string type is itself static,
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-- then the index type is static, so the second case applies only
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-- if the string type passed is non-static.
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function Test (Cond : Boolean) return Uint;
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pragma Inline (Test);
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-- This function simply returns the appropriate Boolean'Pos value
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-- corresponding to the value of Cond as a universal integer. It is
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-- used for producing the result of the static evaluation of the
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-- logical operators
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procedure Test_Expression_Is_Foldable
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(N : Node_Id;
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Op1 : Node_Id;
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Stat : out Boolean;
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Fold : out Boolean);
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-- Tests to see if expression N whose single operand is Op1 is foldable,
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-- i.e. the operand value is known at compile time. If the operation is
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-- foldable, then Fold is True on return, and Stat indicates whether
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-- the result is static (i.e. both operands were static). Note that it
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-- is quite possible for Fold to be True, and Stat to be False, since
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-- there are cases in which we know the value of an operand even though
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-- it is not technically static (e.g. the static lower bound of a range
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-- whose upper bound is non-static).
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--
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-- If Stat is set False on return, then Expression_Is_Foldable makes a
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-- call to Check_Non_Static_Context on the operand. If Fold is False on
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-- return, then all processing is complete, and the caller should
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-- return, since there is nothing else to do.
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procedure Test_Expression_Is_Foldable
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(N : Node_Id;
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Op1 : Node_Id;
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Op2 : Node_Id;
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Stat : out Boolean;
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Fold : out Boolean);
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-- Same processing, except applies to an expression N with two operands
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-- Op1 and Op2.
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procedure To_Bits (U : Uint; B : out Bits);
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-- Converts a Uint value to a bit string of length B'Length
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------------------------------
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-- Check_Non_Static_Context --
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------------------------------
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procedure Check_Non_Static_Context (N : Node_Id) is
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T : constant Entity_Id := Etype (N);
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Checks_On : constant Boolean :=
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not Index_Checks_Suppressed (T)
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and not Range_Checks_Suppressed (T);
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begin
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-- Ignore cases of non-scalar types or error types
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if T = Any_Type or else not Is_Scalar_Type (T) then
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return;
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end if;
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-- At this stage we have a scalar type. If we have an expression
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-- that raises CE, then we already issued a warning or error msg
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-- so there is nothing more to be done in this routine.
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if Raises_Constraint_Error (N) then
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return;
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end if;
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-- Now we have a scalar type which is not marked as raising a
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-- constraint error exception. The main purpose of this routine
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-- is to deal with static expressions appearing in a non-static
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-- context. That means that if we do not have a static expression
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-- then there is not much to do. The one case that we deal with
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-- here is that if we have a floating-point value that is out of
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-- range, then we post a warning that an infinity will result.
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if not Is_Static_Expression (N) then
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if Is_Floating_Point_Type (T)
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and then Is_Out_Of_Range (N, Base_Type (T))
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then
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Error_Msg_N
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("?float value out of range, infinity will be generated", N);
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end if;
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return;
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end if;
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-- Here we have the case of outer level static expression of
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-- scalar type, where the processing of this procedure is needed.
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-- For real types, this is where we convert the value to a machine
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-- number (see RM 4.9(38)). Also see ACVC test C490001. We should
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-- only need to do this if the parent is a constant declaration,
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-- since in other cases, gigi should do the necessary conversion
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-- correctly, but experimentation shows that this is not the case
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-- on all machines, in particular if we do not convert all literals
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-- to machine values in non-static contexts, then ACVC test C490001
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-- fails on Sparc/Solaris and SGI/Irix.
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if Nkind (N) = N_Real_Literal
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and then not Is_Machine_Number (N)
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and then not Is_Generic_Type (Etype (N))
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and then Etype (N) /= Universal_Real
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then
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-- Check that value is in bounds before converting to machine
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-- number, so as not to lose case where value overflows in the
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-- least significant bit or less. See B490001.
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if Is_Out_Of_Range (N, Base_Type (T)) then
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Out_Of_Range (N);
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return;
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end if;
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-- Note: we have to copy the node, to avoid problems with conformance
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-- of very similar numbers (see ACVC tests B4A010C and B63103A).
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Rewrite (N, New_Copy (N));
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if not Is_Floating_Point_Type (T) then
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Set_Realval
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(N, Corresponding_Integer_Value (N) * Small_Value (T));
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elsif not UR_Is_Zero (Realval (N)) then
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-- Note: even though RM 4.9(38) specifies biased rounding,
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-- this has been modified by AI-100 in order to prevent
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-- confusing differences in rounding between static and
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-- non-static expressions. AI-100 specifies that the effect
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-- of such rounding is implementation dependent, and in GNAT
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-- we round to nearest even to match the run-time behavior.
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Set_Realval
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(N, Machine (Base_Type (T), Realval (N), Round_Even, N));
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end if;
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Set_Is_Machine_Number (N);
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end if;
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-- Check for out of range universal integer. This is a non-static
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-- context, so the integer value must be in range of the runtime
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-- representation of universal integers.
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-- We do this only within an expression, because that is the only
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-- case in which non-static universal integer values can occur, and
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-- furthermore, Check_Non_Static_Context is currently (incorrectly???)
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-- called in contexts like the expression of a number declaration where
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-- we certainly want to allow out of range values.
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if Etype (N) = Universal_Integer
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and then Nkind (N) = N_Integer_Literal
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and then Nkind (Parent (N)) in N_Subexpr
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and then
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(Intval (N) < Expr_Value (Type_Low_Bound (Universal_Integer))
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or else
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Intval (N) > Expr_Value (Type_High_Bound (Universal_Integer)))
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then
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Apply_Compile_Time_Constraint_Error
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(N, "non-static universal integer value out of range?",
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CE_Range_Check_Failed);
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-- Check out of range of base type
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elsif Is_Out_Of_Range (N, Base_Type (T)) then
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Out_Of_Range (N);
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-- Give warning if outside subtype (where one or both of the
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-- bounds of the subtype is static). This warning is omitted
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-- if the expression appears in a range that could be null
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-- (warnings are handled elsewhere for this case).
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elsif T /= Base_Type (T)
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and then Nkind (Parent (N)) /= N_Range
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then
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if Is_In_Range (N, T) then
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null;
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elsif Is_Out_Of_Range (N, T) then
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Apply_Compile_Time_Constraint_Error
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(N, "value not in range of}?", CE_Range_Check_Failed);
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elsif Checks_On then
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Enable_Range_Check (N);
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else
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Set_Do_Range_Check (N, False);
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end if;
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end if;
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end Check_Non_Static_Context;
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---------------------------------
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-- Check_String_Literal_Length --
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---------------------------------
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procedure Check_String_Literal_Length (N : Node_Id; Ttype : Entity_Id) is
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begin
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if not Raises_Constraint_Error (N)
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and then Is_Constrained (Ttype)
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then
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if
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UI_From_Int (String_Length (Strval (N))) /= String_Type_Len (Ttype)
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then
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Apply_Compile_Time_Constraint_Error
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(N, "string length wrong for}?",
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CE_Length_Check_Failed,
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Ent => Ttype,
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Typ => Ttype);
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end if;
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end if;
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end Check_String_Literal_Length;
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--------------------------
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-- Compile_Time_Compare --
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--------------------------
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function Compile_Time_Compare
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(L, R : Node_Id;
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Rec : Boolean := False)
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return Compare_Result
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is
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Ltyp : constant Entity_Id := Etype (L);
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Rtyp : constant Entity_Id := Etype (R);
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procedure Compare_Decompose
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(N : Node_Id;
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R : out Node_Id;
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V : out Uint);
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-- This procedure decomposes the node N into an expression node
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-- and a signed offset, so that the value of N is equal to the
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-- value of R plus the value V (which may be negative). If no
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-- such decomposition is possible, then on return R is a copy
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-- of N, and V is set to zero.
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function Compare_Fixup (N : Node_Id) return Node_Id;
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-- This function deals with replacing 'Last and 'First references
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-- with their corresponding type bounds, which we then can compare.
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-- The argument is the original node, the result is the identity,
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-- unless we have a 'Last/'First reference in which case the value
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-- returned is the appropriate type bound.
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function Is_Same_Value (L, R : Node_Id) return Boolean;
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-- Returns True iff L and R represent expressions that definitely
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-- have identical (but not necessarily compile time known) values
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-- Indeed the caller is expected to have already dealt with the
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-- cases of compile time known values, so these are not tested here.
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-----------------------
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-- Compare_Decompose --
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-----------------------
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procedure Compare_Decompose
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(N : Node_Id;
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R : out Node_Id;
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V : out Uint)
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is
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begin
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if Nkind (N) = N_Op_Add
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and then Nkind (Right_Opnd (N)) = N_Integer_Literal
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then
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R := Left_Opnd (N);
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V := Intval (Right_Opnd (N));
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return;
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elsif Nkind (N) = N_Op_Subtract
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and then Nkind (Right_Opnd (N)) = N_Integer_Literal
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then
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R := Left_Opnd (N);
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V := UI_Negate (Intval (Right_Opnd (N)));
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return;
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elsif Nkind (N) = N_Attribute_Reference then
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if Attribute_Name (N) = Name_Succ then
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R := First (Expressions (N));
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V := Uint_1;
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return;
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elsif Attribute_Name (N) = Name_Pred then
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R := First (Expressions (N));
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V := Uint_Minus_1;
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return;
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end if;
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end if;
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R := N;
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V := Uint_0;
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end Compare_Decompose;
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-------------------
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-- Compare_Fixup --
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-------------------
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function Compare_Fixup (N : Node_Id) return Node_Id is
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Indx : Node_Id;
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Xtyp : Entity_Id;
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Subs : Nat;
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begin
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if Nkind (N) = N_Attribute_Reference
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and then (Attribute_Name (N) = Name_First
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or else
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Attribute_Name (N) = Name_Last)
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then
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Xtyp := Etype (Prefix (N));
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-- If we have no type, then just abandon the attempt to do
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-- a fixup, this is probably the result of some other error.
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if No (Xtyp) then
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return N;
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end if;
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-- Dereference an access type
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if Is_Access_Type (Xtyp) then
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Xtyp := Designated_Type (Xtyp);
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end if;
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|
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-- If we don't have an array type at this stage, something
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-- is peculiar, e.g. another error, and we abandon the attempt
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-- at a fixup.
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if not Is_Array_Type (Xtyp) then
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return N;
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end if;
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|
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-- Ignore unconstrained array, since bounds are not meaningful
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if not Is_Constrained (Xtyp) then
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return N;
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end if;
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if Ekind (Xtyp) = E_String_Literal_Subtype then
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if Attribute_Name (N) = Name_First then
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return String_Literal_Low_Bound (Xtyp);
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else -- Attribute_Name (N) = Name_Last
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return Make_Integer_Literal (Sloc (N),
|
|
Intval => Intval (String_Literal_Low_Bound (Xtyp))
|
|
+ String_Literal_Length (Xtyp));
|
|
end if;
|
|
end if;
|
|
|
|
-- Find correct index type
|
|
|
|
Indx := First_Index (Xtyp);
|
|
|
|
if Present (Expressions (N)) then
|
|
Subs := UI_To_Int (Expr_Value (First (Expressions (N))));
|
|
|
|
for J in 2 .. Subs loop
|
|
Indx := Next_Index (Indx);
|
|
end loop;
|
|
end if;
|
|
|
|
Xtyp := Etype (Indx);
|
|
|
|
if Attribute_Name (N) = Name_First then
|
|
return Type_Low_Bound (Xtyp);
|
|
|
|
else -- Attribute_Name (N) = Name_Last
|
|
return Type_High_Bound (Xtyp);
|
|
end if;
|
|
end if;
|
|
|
|
return N;
|
|
end Compare_Fixup;
|
|
|
|
-------------------
|
|
-- Is_Same_Value --
|
|
-------------------
|
|
|
|
function Is_Same_Value (L, R : Node_Id) return Boolean is
|
|
Lf : constant Node_Id := Compare_Fixup (L);
|
|
Rf : constant Node_Id := Compare_Fixup (R);
|
|
|
|
function Is_Same_Subscript (L, R : List_Id) return Boolean;
|
|
-- L, R are the Expressions values from two attribute nodes
|
|
-- for First or Last attributes. Either may be set to No_List
|
|
-- if no expressions are present (indicating subscript 1).
|
|
-- The result is True if both expressions represent the same
|
|
-- subscript (note that one case is where one subscript is
|
|
-- missing and the other is explicitly set to 1).
|
|
|
|
-----------------------
|
|
-- Is_Same_Subscript --
|
|
-----------------------
|
|
|
|
function Is_Same_Subscript (L, R : List_Id) return Boolean is
|
|
begin
|
|
if L = No_List then
|
|
if R = No_List then
|
|
return True;
|
|
else
|
|
return Expr_Value (First (R)) = Uint_1;
|
|
end if;
|
|
|
|
else
|
|
if R = No_List then
|
|
return Expr_Value (First (L)) = Uint_1;
|
|
else
|
|
return Expr_Value (First (L)) = Expr_Value (First (R));
|
|
end if;
|
|
end if;
|
|
end Is_Same_Subscript;
|
|
|
|
-- Start of processing for Is_Same_Value
|
|
|
|
begin
|
|
-- Values are the same if they are the same identifier and the
|
|
-- identifier refers to a constant object (E_Constant). This
|
|
-- does not however apply to Float types, since we may have two
|
|
-- NaN values and they should never compare equal.
|
|
|
|
if Nkind (Lf) = N_Identifier and then Nkind (Rf) = N_Identifier
|
|
and then Entity (Lf) = Entity (Rf)
|
|
and then not Is_Floating_Point_Type (Etype (L))
|
|
and then (Ekind (Entity (Lf)) = E_Constant or else
|
|
Ekind (Entity (Lf)) = E_In_Parameter or else
|
|
Ekind (Entity (Lf)) = E_Loop_Parameter)
|
|
then
|
|
return True;
|
|
|
|
-- Or if they are compile time known and identical
|
|
|
|
elsif Compile_Time_Known_Value (Lf)
|
|
and then
|
|
Compile_Time_Known_Value (Rf)
|
|
and then Expr_Value (Lf) = Expr_Value (Rf)
|
|
then
|
|
return True;
|
|
|
|
-- Or if they are both 'First or 'Last values applying to the
|
|
-- same entity (first and last don't change even if value does)
|
|
|
|
elsif Nkind (Lf) = N_Attribute_Reference
|
|
and then
|
|
Nkind (Rf) = N_Attribute_Reference
|
|
and then Attribute_Name (Lf) = Attribute_Name (Rf)
|
|
and then (Attribute_Name (Lf) = Name_First
|
|
or else
|
|
Attribute_Name (Lf) = Name_Last)
|
|
and then Is_Entity_Name (Prefix (Lf))
|
|
and then Is_Entity_Name (Prefix (Rf))
|
|
and then Entity (Prefix (Lf)) = Entity (Prefix (Rf))
|
|
and then Is_Same_Subscript (Expressions (Lf), Expressions (Rf))
|
|
then
|
|
return True;
|
|
|
|
-- All other cases, we can't tell
|
|
|
|
else
|
|
return False;
|
|
end if;
|
|
end Is_Same_Value;
|
|
|
|
-- Start of processing for Compile_Time_Compare
|
|
|
|
begin
|
|
-- If either operand could raise constraint error, then we cannot
|
|
-- know the result at compile time (since CE may be raised!)
|
|
|
|
if not (Cannot_Raise_Constraint_Error (L)
|
|
and then
|
|
Cannot_Raise_Constraint_Error (R))
|
|
then
|
|
return Unknown;
|
|
end if;
|
|
|
|
-- Identical operands are most certainly equal
|
|
|
|
if L = R then
|
|
return EQ;
|
|
|
|
-- If expressions have no types, then do not attempt to determine
|
|
-- if they are the same, since something funny is going on. One
|
|
-- case in which this happens is during generic template analysis,
|
|
-- when bounds are not fully analyzed.
|
|
|
|
elsif No (Ltyp) or else No (Rtyp) then
|
|
return Unknown;
|
|
|
|
-- We only attempt compile time analysis for scalar values, and
|
|
-- not for packed arrays represented as modular types, where the
|
|
-- semantics of comparison is quite different.
|
|
|
|
elsif not Is_Scalar_Type (Ltyp)
|
|
or else Is_Packed_Array_Type (Ltyp)
|
|
then
|
|
return Unknown;
|
|
|
|
-- Case where comparison involves two compile time known values
|
|
|
|
elsif Compile_Time_Known_Value (L)
|
|
and then Compile_Time_Known_Value (R)
|
|
then
|
|
-- For the floating-point case, we have to be a little careful, since
|
|
-- at compile time we are dealing with universal exact values, but at
|
|
-- runtime, these will be in non-exact target form. That's why the
|
|
-- returned results are LE and GE below instead of LT and GT.
|
|
|
|
if Is_Floating_Point_Type (Ltyp)
|
|
or else
|
|
Is_Floating_Point_Type (Rtyp)
|
|
then
|
|
declare
|
|
Lo : constant Ureal := Expr_Value_R (L);
|
|
Hi : constant Ureal := Expr_Value_R (R);
|
|
|
|
begin
|
|
if Lo < Hi then
|
|
return LE;
|
|
elsif Lo = Hi then
|
|
return EQ;
|
|
else
|
|
return GE;
|
|
end if;
|
|
end;
|
|
|
|
-- For the integer case we know exactly (note that this includes the
|
|
-- fixed-point case, where we know the run time integer values now)
|
|
|
|
else
|
|
declare
|
|
Lo : constant Uint := Expr_Value (L);
|
|
Hi : constant Uint := Expr_Value (R);
|
|
|
|
begin
|
|
if Lo < Hi then
|
|
return LT;
|
|
elsif Lo = Hi then
|
|
return EQ;
|
|
else
|
|
return GT;
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
-- Cases where at least one operand is not known at compile time
|
|
|
|
else
|
|
-- Here is where we check for comparisons against maximum bounds of
|
|
-- types, where we know that no value can be outside the bounds of
|
|
-- the subtype. Note that this routine is allowed to assume that all
|
|
-- expressions are within their subtype bounds. Callers wishing to
|
|
-- deal with possibly invalid values must in any case take special
|
|
-- steps (e.g. conversions to larger types) to avoid this kind of
|
|
-- optimization, which is always considered to be valid. We do not
|
|
-- attempt this optimization with generic types, since the type
|
|
-- bounds may not be meaningful in this case.
|
|
|
|
-- We are in danger of an infinite recursion here. It does not seem
|
|
-- useful to go more than one level deep, so the parameter Rec is
|
|
-- used to protect ourselves against this infinite recursion.
|
|
|
|
if not Rec
|
|
and then Is_Discrete_Type (Ltyp)
|
|
and then Is_Discrete_Type (Rtyp)
|
|
and then not Is_Generic_Type (Ltyp)
|
|
and then not Is_Generic_Type (Rtyp)
|
|
then
|
|
-- See if we can get a decisive check against one operand and
|
|
-- a bound of the other operand (four possible tests here).
|
|
|
|
case Compile_Time_Compare (L, Type_Low_Bound (Rtyp), True) is
|
|
when LT => return LT;
|
|
when LE => return LE;
|
|
when EQ => return LE;
|
|
when others => null;
|
|
end case;
|
|
|
|
case Compile_Time_Compare (L, Type_High_Bound (Rtyp), True) is
|
|
when GT => return GT;
|
|
when GE => return GE;
|
|
when EQ => return GE;
|
|
when others => null;
|
|
end case;
|
|
|
|
case Compile_Time_Compare (Type_Low_Bound (Ltyp), R, True) is
|
|
when GT => return GT;
|
|
when GE => return GE;
|
|
when EQ => return GE;
|
|
when others => null;
|
|
end case;
|
|
|
|
case Compile_Time_Compare (Type_High_Bound (Ltyp), R, True) is
|
|
when LT => return LT;
|
|
when LE => return LE;
|
|
when EQ => return LE;
|
|
when others => null;
|
|
end case;
|
|
end if;
|
|
|
|
-- Next attempt is to decompose the expressions to extract
|
|
-- a constant offset resulting from the use of any of the forms:
|
|
|
|
-- expr + literal
|
|
-- expr - literal
|
|
-- typ'Succ (expr)
|
|
-- typ'Pred (expr)
|
|
|
|
-- Then we see if the two expressions are the same value, and if so
|
|
-- the result is obtained by comparing the offsets.
|
|
|
|
declare
|
|
Lnode : Node_Id;
|
|
Loffs : Uint;
|
|
Rnode : Node_Id;
|
|
Roffs : Uint;
|
|
|
|
begin
|
|
Compare_Decompose (L, Lnode, Loffs);
|
|
Compare_Decompose (R, Rnode, Roffs);
|
|
|
|
if Is_Same_Value (Lnode, Rnode) then
|
|
if Loffs = Roffs then
|
|
return EQ;
|
|
|
|
elsif Loffs < Roffs then
|
|
return LT;
|
|
|
|
else
|
|
return GT;
|
|
end if;
|
|
|
|
-- If the expressions are different, we cannot say at compile
|
|
-- time how they compare, so we return the Unknown indication.
|
|
|
|
else
|
|
return Unknown;
|
|
end if;
|
|
end;
|
|
end if;
|
|
end Compile_Time_Compare;
|
|
|
|
------------------------------
|
|
-- Compile_Time_Known_Value --
|
|
------------------------------
|
|
|
|
function Compile_Time_Known_Value (Op : Node_Id) return Boolean is
|
|
K : constant Node_Kind := Nkind (Op);
|
|
CV_Ent : CV_Entry renames CV_Cache (Nat (Op) mod CV_Cache_Size);
|
|
|
|
begin
|
|
-- Never known at compile time if bad type or raises constraint error
|
|
-- or empty (latter case occurs only as a result of a previous error)
|
|
|
|
if No (Op)
|
|
or else Op = Error
|
|
or else Etype (Op) = Any_Type
|
|
or else Raises_Constraint_Error (Op)
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
-- If this is not a static expression and we are in configurable run
|
|
-- time mode, then we consider it not known at compile time. This
|
|
-- avoids anomalies where whether something is permitted with a given
|
|
-- configurable run-time library depends on how good the compiler is
|
|
-- at optimizing and knowing that things are constant when they
|
|
-- are non-static.
|
|
|
|
if Configurable_Run_Time_Mode and then not Is_Static_Expression (Op) then
|
|
return False;
|
|
end if;
|
|
|
|
-- If we have an entity name, then see if it is the name of a constant
|
|
-- and if so, test the corresponding constant value, or the name of
|
|
-- an enumeration literal, which is always a constant.
|
|
|
|
if Present (Etype (Op)) and then Is_Entity_Name (Op) then
|
|
declare
|
|
E : constant Entity_Id := Entity (Op);
|
|
V : Node_Id;
|
|
|
|
begin
|
|
-- Never known at compile time if it is a packed array value.
|
|
-- We might want to try to evaluate these at compile time one
|
|
-- day, but we do not make that attempt now.
|
|
|
|
if Is_Packed_Array_Type (Etype (Op)) then
|
|
return False;
|
|
end if;
|
|
|
|
if Ekind (E) = E_Enumeration_Literal then
|
|
return True;
|
|
|
|
elsif Ekind (E) = E_Constant then
|
|
V := Constant_Value (E);
|
|
return Present (V) and then Compile_Time_Known_Value (V);
|
|
end if;
|
|
end;
|
|
|
|
-- We have a value, see if it is compile time known
|
|
|
|
else
|
|
-- Integer literals are worth storing in the cache
|
|
|
|
if K = N_Integer_Literal then
|
|
CV_Ent.N := Op;
|
|
CV_Ent.V := Intval (Op);
|
|
return True;
|
|
|
|
-- Other literals and NULL are known at compile time
|
|
|
|
elsif
|
|
K = N_Character_Literal
|
|
or else
|
|
K = N_Real_Literal
|
|
or else
|
|
K = N_String_Literal
|
|
or else
|
|
K = N_Null
|
|
then
|
|
return True;
|
|
|
|
-- Any reference to Null_Parameter is known at compile time. No
|
|
-- other attribute references (that have not already been folded)
|
|
-- are known at compile time.
|
|
|
|
elsif K = N_Attribute_Reference then
|
|
return Attribute_Name (Op) = Name_Null_Parameter;
|
|
end if;
|
|
end if;
|
|
|
|
-- If we fall through, not known at compile time
|
|
|
|
return False;
|
|
|
|
-- If we get an exception while trying to do this test, then some error
|
|
-- has occurred, and we simply say that the value is not known after all
|
|
|
|
exception
|
|
when others =>
|
|
return False;
|
|
end Compile_Time_Known_Value;
|
|
|
|
--------------------------------------
|
|
-- Compile_Time_Known_Value_Or_Aggr --
|
|
--------------------------------------
|
|
|
|
function Compile_Time_Known_Value_Or_Aggr (Op : Node_Id) return Boolean is
|
|
begin
|
|
-- If we have an entity name, then see if it is the name of a constant
|
|
-- and if so, test the corresponding constant value, or the name of
|
|
-- an enumeration literal, which is always a constant.
|
|
|
|
if Is_Entity_Name (Op) then
|
|
declare
|
|
E : constant Entity_Id := Entity (Op);
|
|
V : Node_Id;
|
|
|
|
begin
|
|
if Ekind (E) = E_Enumeration_Literal then
|
|
return True;
|
|
|
|
elsif Ekind (E) /= E_Constant then
|
|
return False;
|
|
|
|
else
|
|
V := Constant_Value (E);
|
|
return Present (V)
|
|
and then Compile_Time_Known_Value_Or_Aggr (V);
|
|
end if;
|
|
end;
|
|
|
|
-- We have a value, see if it is compile time known
|
|
|
|
else
|
|
if Compile_Time_Known_Value (Op) then
|
|
return True;
|
|
|
|
elsif Nkind (Op) = N_Aggregate then
|
|
|
|
if Present (Expressions (Op)) then
|
|
declare
|
|
Expr : Node_Id;
|
|
|
|
begin
|
|
Expr := First (Expressions (Op));
|
|
while Present (Expr) loop
|
|
if not Compile_Time_Known_Value_Or_Aggr (Expr) then
|
|
return False;
|
|
end if;
|
|
|
|
Next (Expr);
|
|
end loop;
|
|
end;
|
|
end if;
|
|
|
|
if Present (Component_Associations (Op)) then
|
|
declare
|
|
Cass : Node_Id;
|
|
|
|
begin
|
|
Cass := First (Component_Associations (Op));
|
|
while Present (Cass) loop
|
|
if not
|
|
Compile_Time_Known_Value_Or_Aggr (Expression (Cass))
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
Next (Cass);
|
|
end loop;
|
|
end;
|
|
end if;
|
|
|
|
return True;
|
|
|
|
-- All other types of values are not known at compile time
|
|
|
|
else
|
|
return False;
|
|
end if;
|
|
|
|
end if;
|
|
end Compile_Time_Known_Value_Or_Aggr;
|
|
|
|
-----------------
|
|
-- Eval_Actual --
|
|
-----------------
|
|
|
|
-- This is only called for actuals of functions that are not predefined
|
|
-- operators (which have already been rewritten as operators at this
|
|
-- stage), so the call can never be folded, and all that needs doing for
|
|
-- the actual is to do the check for a non-static context.
|
|
|
|
procedure Eval_Actual (N : Node_Id) is
|
|
begin
|
|
Check_Non_Static_Context (N);
|
|
end Eval_Actual;
|
|
|
|
--------------------
|
|
-- Eval_Allocator --
|
|
--------------------
|
|
|
|
-- Allocators are never static, so all we have to do is to do the
|
|
-- check for a non-static context if an expression is present.
|
|
|
|
procedure Eval_Allocator (N : Node_Id) is
|
|
Expr : constant Node_Id := Expression (N);
|
|
|
|
begin
|
|
if Nkind (Expr) = N_Qualified_Expression then
|
|
Check_Non_Static_Context (Expression (Expr));
|
|
end if;
|
|
end Eval_Allocator;
|
|
|
|
------------------------
|
|
-- Eval_Arithmetic_Op --
|
|
------------------------
|
|
|
|
-- Arithmetic operations are static functions, so the result is static
|
|
-- if both operands are static (RM 4.9(7), 4.9(20)).
|
|
|
|
procedure Eval_Arithmetic_Op (N : Node_Id) is
|
|
Left : constant Node_Id := Left_Opnd (N);
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
Ltype : constant Entity_Id := Etype (Left);
|
|
Rtype : constant Entity_Id := Etype (Right);
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
|
|
begin
|
|
-- If not foldable we are done
|
|
|
|
Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
|
|
|
|
if not Fold then
|
|
return;
|
|
end if;
|
|
|
|
-- Fold for cases where both operands are of integer type
|
|
|
|
if Is_Integer_Type (Ltype) and then Is_Integer_Type (Rtype) then
|
|
declare
|
|
Left_Int : constant Uint := Expr_Value (Left);
|
|
Right_Int : constant Uint := Expr_Value (Right);
|
|
Result : Uint;
|
|
|
|
begin
|
|
case Nkind (N) is
|
|
|
|
when N_Op_Add =>
|
|
Result := Left_Int + Right_Int;
|
|
|
|
when N_Op_Subtract =>
|
|
Result := Left_Int - Right_Int;
|
|
|
|
when N_Op_Multiply =>
|
|
if OK_Bits
|
|
(N, UI_From_Int
|
|
(Num_Bits (Left_Int) + Num_Bits (Right_Int)))
|
|
then
|
|
Result := Left_Int * Right_Int;
|
|
else
|
|
Result := Left_Int;
|
|
end if;
|
|
|
|
when N_Op_Divide =>
|
|
|
|
-- The exception Constraint_Error is raised by integer
|
|
-- division, rem and mod if the right operand is zero.
|
|
|
|
if Right_Int = 0 then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "division by zero",
|
|
CE_Divide_By_Zero,
|
|
Warn => not Stat);
|
|
return;
|
|
|
|
else
|
|
Result := Left_Int / Right_Int;
|
|
end if;
|
|
|
|
when N_Op_Mod =>
|
|
|
|
-- The exception Constraint_Error is raised by integer
|
|
-- division, rem and mod if the right operand is zero.
|
|
|
|
if Right_Int = 0 then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "mod with zero divisor",
|
|
CE_Divide_By_Zero,
|
|
Warn => not Stat);
|
|
return;
|
|
else
|
|
Result := Left_Int mod Right_Int;
|
|
end if;
|
|
|
|
when N_Op_Rem =>
|
|
|
|
-- The exception Constraint_Error is raised by integer
|
|
-- division, rem and mod if the right operand is zero.
|
|
|
|
if Right_Int = 0 then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "rem with zero divisor",
|
|
CE_Divide_By_Zero,
|
|
Warn => not Stat);
|
|
return;
|
|
|
|
else
|
|
Result := Left_Int rem Right_Int;
|
|
end if;
|
|
|
|
when others =>
|
|
raise Program_Error;
|
|
end case;
|
|
|
|
-- Adjust the result by the modulus if the type is a modular type
|
|
|
|
if Is_Modular_Integer_Type (Ltype) then
|
|
Result := Result mod Modulus (Ltype);
|
|
end if;
|
|
|
|
Fold_Uint (N, Result, Stat);
|
|
end;
|
|
|
|
-- Cases where at least one operand is a real. We handle the cases
|
|
-- of both reals, or mixed/real integer cases (the latter happen
|
|
-- only for divide and multiply, and the result is always real).
|
|
|
|
elsif Is_Real_Type (Ltype) or else Is_Real_Type (Rtype) then
|
|
declare
|
|
Left_Real : Ureal;
|
|
Right_Real : Ureal;
|
|
Result : Ureal;
|
|
|
|
begin
|
|
if Is_Real_Type (Ltype) then
|
|
Left_Real := Expr_Value_R (Left);
|
|
else
|
|
Left_Real := UR_From_Uint (Expr_Value (Left));
|
|
end if;
|
|
|
|
if Is_Real_Type (Rtype) then
|
|
Right_Real := Expr_Value_R (Right);
|
|
else
|
|
Right_Real := UR_From_Uint (Expr_Value (Right));
|
|
end if;
|
|
|
|
if Nkind (N) = N_Op_Add then
|
|
Result := Left_Real + Right_Real;
|
|
|
|
elsif Nkind (N) = N_Op_Subtract then
|
|
Result := Left_Real - Right_Real;
|
|
|
|
elsif Nkind (N) = N_Op_Multiply then
|
|
Result := Left_Real * Right_Real;
|
|
|
|
else pragma Assert (Nkind (N) = N_Op_Divide);
|
|
if UR_Is_Zero (Right_Real) then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "division by zero", CE_Divide_By_Zero);
|
|
return;
|
|
end if;
|
|
|
|
Result := Left_Real / Right_Real;
|
|
end if;
|
|
|
|
Fold_Ureal (N, Result, Stat);
|
|
end;
|
|
end if;
|
|
end Eval_Arithmetic_Op;
|
|
|
|
----------------------------
|
|
-- Eval_Character_Literal --
|
|
----------------------------
|
|
|
|
-- Nothing to be done!
|
|
|
|
procedure Eval_Character_Literal (N : Node_Id) is
|
|
pragma Warnings (Off, N);
|
|
|
|
begin
|
|
null;
|
|
end Eval_Character_Literal;
|
|
|
|
---------------
|
|
-- Eval_Call --
|
|
---------------
|
|
|
|
-- Static function calls are either calls to predefined operators
|
|
-- with static arguments, or calls to functions that rename a literal.
|
|
-- Only the latter case is handled here, predefined operators are
|
|
-- constant-folded elsewhere.
|
|
-- If the function is itself inherited (see 7423-001) the literal of
|
|
-- the parent type must be explicitly converted to the return type
|
|
-- of the function.
|
|
|
|
procedure Eval_Call (N : Node_Id) is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Typ : constant Entity_Id := Etype (N);
|
|
Lit : Entity_Id;
|
|
|
|
begin
|
|
if Nkind (N) = N_Function_Call
|
|
and then No (Parameter_Associations (N))
|
|
and then Is_Entity_Name (Name (N))
|
|
and then Present (Alias (Entity (Name (N))))
|
|
and then Is_Enumeration_Type (Base_Type (Typ))
|
|
then
|
|
Lit := Alias (Entity (Name (N)));
|
|
|
|
while Present (Alias (Lit)) loop
|
|
Lit := Alias (Lit);
|
|
end loop;
|
|
|
|
if Ekind (Lit) = E_Enumeration_Literal then
|
|
if Base_Type (Etype (Lit)) /= Base_Type (Typ) then
|
|
Rewrite
|
|
(N, Convert_To (Typ, New_Occurrence_Of (Lit, Loc)));
|
|
else
|
|
Rewrite (N, New_Occurrence_Of (Lit, Loc));
|
|
end if;
|
|
|
|
Resolve (N, Typ);
|
|
end if;
|
|
end if;
|
|
end Eval_Call;
|
|
|
|
------------------------
|
|
-- Eval_Concatenation --
|
|
------------------------
|
|
|
|
-- Concatenation is a static function, so the result is static if
|
|
-- both operands are static (RM 4.9(7), 4.9(21)).
|
|
|
|
procedure Eval_Concatenation (N : Node_Id) is
|
|
Left : constant Node_Id := Left_Opnd (N);
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
C_Typ : constant Entity_Id := Root_Type (Component_Type (Etype (N)));
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
|
|
begin
|
|
-- Concatenation is never static in Ada 83, so if Ada 83
|
|
-- check operand non-static context
|
|
|
|
if Ada_Version = Ada_83
|
|
and then Comes_From_Source (N)
|
|
then
|
|
Check_Non_Static_Context (Left);
|
|
Check_Non_Static_Context (Right);
|
|
return;
|
|
end if;
|
|
|
|
-- If not foldable we are done. In principle concatenation that yields
|
|
-- any string type is static (i.e. an array type of character types).
|
|
-- However, character types can include enumeration literals, and
|
|
-- concatenation in that case cannot be described by a literal, so we
|
|
-- only consider the operation static if the result is an array of
|
|
-- (a descendant of) a predefined character type.
|
|
|
|
Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
|
|
|
|
if (C_Typ = Standard_Character
|
|
or else C_Typ = Standard_Wide_Character)
|
|
and then Fold
|
|
then
|
|
null;
|
|
else
|
|
Set_Is_Static_Expression (N, False);
|
|
return;
|
|
end if;
|
|
|
|
-- Compile time string concatenation.
|
|
|
|
-- ??? Note that operands that are aggregates can be marked as
|
|
-- static, so we should attempt at a later stage to fold
|
|
-- concatenations with such aggregates.
|
|
|
|
declare
|
|
Left_Str : constant Node_Id := Get_String_Val (Left);
|
|
Left_Len : Nat;
|
|
Right_Str : constant Node_Id := Get_String_Val (Right);
|
|
|
|
begin
|
|
-- Establish new string literal, and store left operand. We make
|
|
-- sure to use the special Start_String that takes an operand if
|
|
-- the left operand is a string literal. Since this is optimized
|
|
-- in the case where that is the most recently created string
|
|
-- literal, we ensure efficient time/space behavior for the
|
|
-- case of a concatenation of a series of string literals.
|
|
|
|
if Nkind (Left_Str) = N_String_Literal then
|
|
Left_Len := String_Length (Strval (Left_Str));
|
|
Start_String (Strval (Left_Str));
|
|
else
|
|
Start_String;
|
|
Store_String_Char (Char_Literal_Value (Left_Str));
|
|
Left_Len := 1;
|
|
end if;
|
|
|
|
-- Now append the characters of the right operand
|
|
|
|
if Nkind (Right_Str) = N_String_Literal then
|
|
declare
|
|
S : constant String_Id := Strval (Right_Str);
|
|
|
|
begin
|
|
for J in 1 .. String_Length (S) loop
|
|
Store_String_Char (Get_String_Char (S, J));
|
|
end loop;
|
|
end;
|
|
else
|
|
Store_String_Char (Char_Literal_Value (Right_Str));
|
|
end if;
|
|
|
|
Set_Is_Static_Expression (N, Stat);
|
|
|
|
if Stat then
|
|
|
|
-- If left operand is the empty string, the result is the
|
|
-- right operand, including its bounds if anomalous.
|
|
|
|
if Left_Len = 0
|
|
and then Is_Array_Type (Etype (Right))
|
|
and then Etype (Right) /= Any_String
|
|
then
|
|
Set_Etype (N, Etype (Right));
|
|
end if;
|
|
|
|
Fold_Str (N, End_String, True);
|
|
end if;
|
|
end;
|
|
end Eval_Concatenation;
|
|
|
|
---------------------------------
|
|
-- Eval_Conditional_Expression --
|
|
---------------------------------
|
|
|
|
-- This GNAT internal construct can never be statically folded, so the
|
|
-- only required processing is to do the check for non-static context
|
|
-- for the two expression operands.
|
|
|
|
procedure Eval_Conditional_Expression (N : Node_Id) is
|
|
Condition : constant Node_Id := First (Expressions (N));
|
|
Then_Expr : constant Node_Id := Next (Condition);
|
|
Else_Expr : constant Node_Id := Next (Then_Expr);
|
|
|
|
begin
|
|
Check_Non_Static_Context (Then_Expr);
|
|
Check_Non_Static_Context (Else_Expr);
|
|
end Eval_Conditional_Expression;
|
|
|
|
----------------------
|
|
-- Eval_Entity_Name --
|
|
----------------------
|
|
|
|
-- This procedure is used for identifiers and expanded names other than
|
|
-- named numbers (see Eval_Named_Integer, Eval_Named_Real. These are
|
|
-- static if they denote a static constant (RM 4.9(6)) or if the name
|
|
-- denotes an enumeration literal (RM 4.9(22)).
|
|
|
|
procedure Eval_Entity_Name (N : Node_Id) is
|
|
Def_Id : constant Entity_Id := Entity (N);
|
|
Val : Node_Id;
|
|
|
|
begin
|
|
-- Enumeration literals are always considered to be constants
|
|
-- and cannot raise constraint error (RM 4.9(22)).
|
|
|
|
if Ekind (Def_Id) = E_Enumeration_Literal then
|
|
Set_Is_Static_Expression (N);
|
|
return;
|
|
|
|
-- A name is static if it denotes a static constant (RM 4.9(5)), and
|
|
-- we also copy Raise_Constraint_Error. Notice that even if non-static,
|
|
-- it does not violate 10.2.1(8) here, since this is not a variable.
|
|
|
|
elsif Ekind (Def_Id) = E_Constant then
|
|
|
|
-- Deferred constants must always be treated as nonstatic
|
|
-- outside the scope of their full view.
|
|
|
|
if Present (Full_View (Def_Id))
|
|
and then not In_Open_Scopes (Scope (Def_Id))
|
|
then
|
|
Val := Empty;
|
|
else
|
|
Val := Constant_Value (Def_Id);
|
|
end if;
|
|
|
|
if Present (Val) then
|
|
Set_Is_Static_Expression
|
|
(N, Is_Static_Expression (Val)
|
|
and then Is_Static_Subtype (Etype (Def_Id)));
|
|
Set_Raises_Constraint_Error (N, Raises_Constraint_Error (Val));
|
|
|
|
if not Is_Static_Expression (N)
|
|
and then not Is_Generic_Type (Etype (N))
|
|
then
|
|
Validate_Static_Object_Name (N);
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
end if;
|
|
|
|
-- Fall through if the name is not static.
|
|
|
|
Validate_Static_Object_Name (N);
|
|
end Eval_Entity_Name;
|
|
|
|
----------------------------
|
|
-- Eval_Indexed_Component --
|
|
----------------------------
|
|
|
|
-- Indexed components are never static, so we need to perform the check
|
|
-- for non-static context on the index values. Then, we check if the
|
|
-- value can be obtained at compile time, even though it is non-static.
|
|
|
|
procedure Eval_Indexed_Component (N : Node_Id) is
|
|
Expr : Node_Id;
|
|
|
|
begin
|
|
-- Check for non-static context on index values
|
|
|
|
Expr := First (Expressions (N));
|
|
while Present (Expr) loop
|
|
Check_Non_Static_Context (Expr);
|
|
Next (Expr);
|
|
end loop;
|
|
|
|
-- If the indexed component appears in an object renaming declaration
|
|
-- then we do not want to try to evaluate it, since in this case we
|
|
-- need the identity of the array element.
|
|
|
|
if Nkind (Parent (N)) = N_Object_Renaming_Declaration then
|
|
return;
|
|
|
|
-- Similarly if the indexed component appears as the prefix of an
|
|
-- attribute we don't want to evaluate it, because at least for
|
|
-- some cases of attributes we need the identify (e.g. Access, Size)
|
|
|
|
elsif Nkind (Parent (N)) = N_Attribute_Reference then
|
|
return;
|
|
end if;
|
|
|
|
-- Note: there are other cases, such as the left side of an assignment,
|
|
-- or an OUT parameter for a call, where the replacement results in the
|
|
-- illegal use of a constant, But these cases are illegal in the first
|
|
-- place, so the replacement, though silly, is harmless.
|
|
|
|
-- Now see if this is a constant array reference
|
|
|
|
if List_Length (Expressions (N)) = 1
|
|
and then Is_Entity_Name (Prefix (N))
|
|
and then Ekind (Entity (Prefix (N))) = E_Constant
|
|
and then Present (Constant_Value (Entity (Prefix (N))))
|
|
then
|
|
declare
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Arr : constant Node_Id := Constant_Value (Entity (Prefix (N)));
|
|
Sub : constant Node_Id := First (Expressions (N));
|
|
|
|
Atyp : Entity_Id;
|
|
-- Type of array
|
|
|
|
Lin : Nat;
|
|
-- Linear one's origin subscript value for array reference
|
|
|
|
Lbd : Node_Id;
|
|
-- Lower bound of the first array index
|
|
|
|
Elm : Node_Id;
|
|
-- Value from constant array
|
|
|
|
begin
|
|
Atyp := Etype (Arr);
|
|
|
|
if Is_Access_Type (Atyp) then
|
|
Atyp := Designated_Type (Atyp);
|
|
end if;
|
|
|
|
-- If we have an array type (we should have but perhaps there
|
|
-- are error cases where this is not the case), then see if we
|
|
-- can do a constant evaluation of the array reference.
|
|
|
|
if Is_Array_Type (Atyp) then
|
|
if Ekind (Atyp) = E_String_Literal_Subtype then
|
|
Lbd := String_Literal_Low_Bound (Atyp);
|
|
else
|
|
Lbd := Type_Low_Bound (Etype (First_Index (Atyp)));
|
|
end if;
|
|
|
|
if Compile_Time_Known_Value (Sub)
|
|
and then Nkind (Arr) = N_Aggregate
|
|
and then Compile_Time_Known_Value (Lbd)
|
|
and then Is_Discrete_Type (Component_Type (Atyp))
|
|
then
|
|
Lin := UI_To_Int (Expr_Value (Sub) - Expr_Value (Lbd)) + 1;
|
|
|
|
if List_Length (Expressions (Arr)) >= Lin then
|
|
Elm := Pick (Expressions (Arr), Lin);
|
|
|
|
-- If the resulting expression is compile time known,
|
|
-- then we can rewrite the indexed component with this
|
|
-- value, being sure to mark the result as non-static.
|
|
-- We also reset the Sloc, in case this generates an
|
|
-- error later on (e.g. 136'Access).
|
|
|
|
if Compile_Time_Known_Value (Elm) then
|
|
Rewrite (N, Duplicate_Subexpr_No_Checks (Elm));
|
|
Set_Is_Static_Expression (N, False);
|
|
Set_Sloc (N, Loc);
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end if;
|
|
end;
|
|
end if;
|
|
end Eval_Indexed_Component;
|
|
|
|
--------------------------
|
|
-- Eval_Integer_Literal --
|
|
--------------------------
|
|
|
|
-- Numeric literals are static (RM 4.9(1)), and have already been marked
|
|
-- as static by the analyzer. The reason we did it that early is to allow
|
|
-- the possibility of turning off the Is_Static_Expression flag after
|
|
-- analysis, but before resolution, when integer literals are generated
|
|
-- in the expander that do not correspond to static expressions.
|
|
|
|
procedure Eval_Integer_Literal (N : Node_Id) is
|
|
T : constant Entity_Id := Etype (N);
|
|
|
|
begin
|
|
-- If the literal appears in a non-expression context, then it is
|
|
-- certainly appearing in a non-static context, so check it. This
|
|
-- is actually a redundant check, since Check_Non_Static_Context
|
|
-- would check it, but it seems worth while avoiding the call.
|
|
|
|
if Nkind (Parent (N)) not in N_Subexpr then
|
|
Check_Non_Static_Context (N);
|
|
end if;
|
|
|
|
-- Modular integer literals must be in their base range
|
|
|
|
if Is_Modular_Integer_Type (T)
|
|
and then Is_Out_Of_Range (N, Base_Type (T))
|
|
then
|
|
Out_Of_Range (N);
|
|
end if;
|
|
end Eval_Integer_Literal;
|
|
|
|
---------------------
|
|
-- Eval_Logical_Op --
|
|
---------------------
|
|
|
|
-- Logical operations are static functions, so the result is potentially
|
|
-- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
|
|
|
|
procedure Eval_Logical_Op (N : Node_Id) is
|
|
Left : constant Node_Id := Left_Opnd (N);
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
|
|
begin
|
|
-- If not foldable we are done
|
|
|
|
Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
|
|
|
|
if not Fold then
|
|
return;
|
|
end if;
|
|
|
|
-- Compile time evaluation of logical operation
|
|
|
|
declare
|
|
Left_Int : constant Uint := Expr_Value (Left);
|
|
Right_Int : constant Uint := Expr_Value (Right);
|
|
|
|
begin
|
|
if Is_Modular_Integer_Type (Etype (N)) then
|
|
declare
|
|
Left_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1);
|
|
Right_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1);
|
|
|
|
begin
|
|
To_Bits (Left_Int, Left_Bits);
|
|
To_Bits (Right_Int, Right_Bits);
|
|
|
|
-- Note: should really be able to use array ops instead of
|
|
-- these loops, but they weren't working at the time ???
|
|
|
|
if Nkind (N) = N_Op_And then
|
|
for J in Left_Bits'Range loop
|
|
Left_Bits (J) := Left_Bits (J) and Right_Bits (J);
|
|
end loop;
|
|
|
|
elsif Nkind (N) = N_Op_Or then
|
|
for J in Left_Bits'Range loop
|
|
Left_Bits (J) := Left_Bits (J) or Right_Bits (J);
|
|
end loop;
|
|
|
|
else
|
|
pragma Assert (Nkind (N) = N_Op_Xor);
|
|
|
|
for J in Left_Bits'Range loop
|
|
Left_Bits (J) := Left_Bits (J) xor Right_Bits (J);
|
|
end loop;
|
|
end if;
|
|
|
|
Fold_Uint (N, From_Bits (Left_Bits, Etype (N)), Stat);
|
|
end;
|
|
|
|
else
|
|
pragma Assert (Is_Boolean_Type (Etype (N)));
|
|
|
|
if Nkind (N) = N_Op_And then
|
|
Fold_Uint (N,
|
|
Test (Is_True (Left_Int) and then Is_True (Right_Int)), Stat);
|
|
|
|
elsif Nkind (N) = N_Op_Or then
|
|
Fold_Uint (N,
|
|
Test (Is_True (Left_Int) or else Is_True (Right_Int)), Stat);
|
|
|
|
else
|
|
pragma Assert (Nkind (N) = N_Op_Xor);
|
|
Fold_Uint (N,
|
|
Test (Is_True (Left_Int) xor Is_True (Right_Int)), Stat);
|
|
end if;
|
|
end if;
|
|
end;
|
|
end Eval_Logical_Op;
|
|
|
|
------------------------
|
|
-- Eval_Membership_Op --
|
|
------------------------
|
|
|
|
-- A membership test is potentially static if the expression is static,
|
|
-- and the range is a potentially static range, or is a subtype mark
|
|
-- denoting a static subtype (RM 4.9(12)).
|
|
|
|
procedure Eval_Membership_Op (N : Node_Id) is
|
|
Left : constant Node_Id := Left_Opnd (N);
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
Def_Id : Entity_Id;
|
|
Lo : Node_Id;
|
|
Hi : Node_Id;
|
|
Result : Boolean;
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
|
|
begin
|
|
-- Ignore if error in either operand, except to make sure that
|
|
-- Any_Type is properly propagated to avoid junk cascaded errors.
|
|
|
|
if Etype (Left) = Any_Type
|
|
or else Etype (Right) = Any_Type
|
|
then
|
|
Set_Etype (N, Any_Type);
|
|
return;
|
|
end if;
|
|
|
|
-- Case of right operand is a subtype name
|
|
|
|
if Is_Entity_Name (Right) then
|
|
Def_Id := Entity (Right);
|
|
|
|
if (Is_Scalar_Type (Def_Id) or else Is_String_Type (Def_Id))
|
|
and then Is_OK_Static_Subtype (Def_Id)
|
|
then
|
|
Test_Expression_Is_Foldable (N, Left, Stat, Fold);
|
|
|
|
if not Fold or else not Stat then
|
|
return;
|
|
end if;
|
|
else
|
|
Check_Non_Static_Context (Left);
|
|
return;
|
|
end if;
|
|
|
|
-- For string membership tests we will check the length
|
|
-- further below.
|
|
|
|
if not Is_String_Type (Def_Id) then
|
|
Lo := Type_Low_Bound (Def_Id);
|
|
Hi := Type_High_Bound (Def_Id);
|
|
|
|
else
|
|
Lo := Empty;
|
|
Hi := Empty;
|
|
end if;
|
|
|
|
-- Case of right operand is a range
|
|
|
|
else
|
|
if Is_Static_Range (Right) then
|
|
Test_Expression_Is_Foldable (N, Left, Stat, Fold);
|
|
|
|
if not Fold or else not Stat then
|
|
return;
|
|
|
|
-- If one bound of range raises CE, then don't try to fold
|
|
|
|
elsif not Is_OK_Static_Range (Right) then
|
|
Check_Non_Static_Context (Left);
|
|
return;
|
|
end if;
|
|
|
|
else
|
|
Check_Non_Static_Context (Left);
|
|
return;
|
|
end if;
|
|
|
|
-- Here we know range is an OK static range
|
|
|
|
Lo := Low_Bound (Right);
|
|
Hi := High_Bound (Right);
|
|
end if;
|
|
|
|
-- For strings we check that the length of the string expression is
|
|
-- compatible with the string subtype if the subtype is constrained,
|
|
-- or if unconstrained then the test is always true.
|
|
|
|
if Is_String_Type (Etype (Right)) then
|
|
if not Is_Constrained (Etype (Right)) then
|
|
Result := True;
|
|
|
|
else
|
|
declare
|
|
Typlen : constant Uint := String_Type_Len (Etype (Right));
|
|
Strlen : constant Uint :=
|
|
UI_From_Int (String_Length (Strval (Get_String_Val (Left))));
|
|
begin
|
|
Result := (Typlen = Strlen);
|
|
end;
|
|
end if;
|
|
|
|
-- Fold the membership test. We know we have a static range and Lo
|
|
-- and Hi are set to the expressions for the end points of this range.
|
|
|
|
elsif Is_Real_Type (Etype (Right)) then
|
|
declare
|
|
Leftval : constant Ureal := Expr_Value_R (Left);
|
|
|
|
begin
|
|
Result := Expr_Value_R (Lo) <= Leftval
|
|
and then Leftval <= Expr_Value_R (Hi);
|
|
end;
|
|
|
|
else
|
|
declare
|
|
Leftval : constant Uint := Expr_Value (Left);
|
|
|
|
begin
|
|
Result := Expr_Value (Lo) <= Leftval
|
|
and then Leftval <= Expr_Value (Hi);
|
|
end;
|
|
end if;
|
|
|
|
if Nkind (N) = N_Not_In then
|
|
Result := not Result;
|
|
end if;
|
|
|
|
Fold_Uint (N, Test (Result), True);
|
|
Warn_On_Known_Condition (N);
|
|
end Eval_Membership_Op;
|
|
|
|
------------------------
|
|
-- Eval_Named_Integer --
|
|
------------------------
|
|
|
|
procedure Eval_Named_Integer (N : Node_Id) is
|
|
begin
|
|
Fold_Uint (N,
|
|
Expr_Value (Expression (Declaration_Node (Entity (N)))), True);
|
|
end Eval_Named_Integer;
|
|
|
|
---------------------
|
|
-- Eval_Named_Real --
|
|
---------------------
|
|
|
|
procedure Eval_Named_Real (N : Node_Id) is
|
|
begin
|
|
Fold_Ureal (N,
|
|
Expr_Value_R (Expression (Declaration_Node (Entity (N)))), True);
|
|
end Eval_Named_Real;
|
|
|
|
-------------------
|
|
-- Eval_Op_Expon --
|
|
-------------------
|
|
|
|
-- Exponentiation is a static functions, so the result is potentially
|
|
-- static if both operands are potentially static (RM 4.9(7), 4.9(20)).
|
|
|
|
procedure Eval_Op_Expon (N : Node_Id) is
|
|
Left : constant Node_Id := Left_Opnd (N);
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
|
|
begin
|
|
-- If not foldable we are done
|
|
|
|
Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
|
|
|
|
if not Fold then
|
|
return;
|
|
end if;
|
|
|
|
-- Fold exponentiation operation
|
|
|
|
declare
|
|
Right_Int : constant Uint := Expr_Value (Right);
|
|
|
|
begin
|
|
-- Integer case
|
|
|
|
if Is_Integer_Type (Etype (Left)) then
|
|
declare
|
|
Left_Int : constant Uint := Expr_Value (Left);
|
|
Result : Uint;
|
|
|
|
begin
|
|
-- Exponentiation of an integer raises the exception
|
|
-- Constraint_Error for a negative exponent (RM 4.5.6)
|
|
|
|
if Right_Int < 0 then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "integer exponent negative",
|
|
CE_Range_Check_Failed,
|
|
Warn => not Stat);
|
|
return;
|
|
|
|
else
|
|
if OK_Bits (N, Num_Bits (Left_Int) * Right_Int) then
|
|
Result := Left_Int ** Right_Int;
|
|
else
|
|
Result := Left_Int;
|
|
end if;
|
|
|
|
if Is_Modular_Integer_Type (Etype (N)) then
|
|
Result := Result mod Modulus (Etype (N));
|
|
end if;
|
|
|
|
Fold_Uint (N, Result, Stat);
|
|
end if;
|
|
end;
|
|
|
|
-- Real case
|
|
|
|
else
|
|
declare
|
|
Left_Real : constant Ureal := Expr_Value_R (Left);
|
|
|
|
begin
|
|
-- Cannot have a zero base with a negative exponent
|
|
|
|
if UR_Is_Zero (Left_Real) then
|
|
|
|
if Right_Int < 0 then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "zero ** negative integer",
|
|
CE_Range_Check_Failed,
|
|
Warn => not Stat);
|
|
return;
|
|
else
|
|
Fold_Ureal (N, Ureal_0, Stat);
|
|
end if;
|
|
|
|
else
|
|
Fold_Ureal (N, Left_Real ** Right_Int, Stat);
|
|
end if;
|
|
end;
|
|
end if;
|
|
end;
|
|
end Eval_Op_Expon;
|
|
|
|
-----------------
|
|
-- Eval_Op_Not --
|
|
-----------------
|
|
|
|
-- The not operation is a static functions, so the result is potentially
|
|
-- static if the operand is potentially static (RM 4.9(7), 4.9(20)).
|
|
|
|
procedure Eval_Op_Not (N : Node_Id) is
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
|
|
begin
|
|
-- If not foldable we are done
|
|
|
|
Test_Expression_Is_Foldable (N, Right, Stat, Fold);
|
|
|
|
if not Fold then
|
|
return;
|
|
end if;
|
|
|
|
-- Fold not operation
|
|
|
|
declare
|
|
Rint : constant Uint := Expr_Value (Right);
|
|
Typ : constant Entity_Id := Etype (N);
|
|
|
|
begin
|
|
-- Negation is equivalent to subtracting from the modulus minus
|
|
-- one. For a binary modulus this is equivalent to the ones-
|
|
-- component of the original value. For non-binary modulus this
|
|
-- is an arbitrary but consistent definition.
|
|
|
|
if Is_Modular_Integer_Type (Typ) then
|
|
Fold_Uint (N, Modulus (Typ) - 1 - Rint, Stat);
|
|
|
|
else
|
|
pragma Assert (Is_Boolean_Type (Typ));
|
|
Fold_Uint (N, Test (not Is_True (Rint)), Stat);
|
|
end if;
|
|
|
|
Set_Is_Static_Expression (N, Stat);
|
|
end;
|
|
end Eval_Op_Not;
|
|
|
|
-------------------------------
|
|
-- Eval_Qualified_Expression --
|
|
-------------------------------
|
|
|
|
-- A qualified expression is potentially static if its subtype mark denotes
|
|
-- a static subtype and its expression is potentially static (RM 4.9 (11)).
|
|
|
|
procedure Eval_Qualified_Expression (N : Node_Id) is
|
|
Operand : constant Node_Id := Expression (N);
|
|
Target_Type : constant Entity_Id := Entity (Subtype_Mark (N));
|
|
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
Hex : Boolean;
|
|
|
|
begin
|
|
-- Can only fold if target is string or scalar and subtype is static
|
|
-- Also, do not fold if our parent is an allocator (this is because
|
|
-- the qualified expression is really part of the syntactic structure
|
|
-- of an allocator, and we do not want to end up with something that
|
|
-- corresponds to "new 1" where the 1 is the result of folding a
|
|
-- qualified expression).
|
|
|
|
if not Is_Static_Subtype (Target_Type)
|
|
or else Nkind (Parent (N)) = N_Allocator
|
|
then
|
|
Check_Non_Static_Context (Operand);
|
|
|
|
-- If operand is known to raise constraint_error, set the
|
|
-- flag on the expression so it does not get optimized away.
|
|
|
|
if Nkind (Operand) = N_Raise_Constraint_Error then
|
|
Set_Raises_Constraint_Error (N);
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- If not foldable we are done
|
|
|
|
Test_Expression_Is_Foldable (N, Operand, Stat, Fold);
|
|
|
|
if not Fold then
|
|
return;
|
|
|
|
-- Don't try fold if target type has constraint error bounds
|
|
|
|
elsif not Is_OK_Static_Subtype (Target_Type) then
|
|
Set_Raises_Constraint_Error (N);
|
|
return;
|
|
end if;
|
|
|
|
-- Here we will fold, save Print_In_Hex indication
|
|
|
|
Hex := Nkind (Operand) = N_Integer_Literal
|
|
and then Print_In_Hex (Operand);
|
|
|
|
-- Fold the result of qualification
|
|
|
|
if Is_Discrete_Type (Target_Type) then
|
|
Fold_Uint (N, Expr_Value (Operand), Stat);
|
|
|
|
-- Preserve Print_In_Hex indication
|
|
|
|
if Hex and then Nkind (N) = N_Integer_Literal then
|
|
Set_Print_In_Hex (N);
|
|
end if;
|
|
|
|
elsif Is_Real_Type (Target_Type) then
|
|
Fold_Ureal (N, Expr_Value_R (Operand), Stat);
|
|
|
|
else
|
|
Fold_Str (N, Strval (Get_String_Val (Operand)), Stat);
|
|
|
|
if not Stat then
|
|
Set_Is_Static_Expression (N, False);
|
|
else
|
|
Check_String_Literal_Length (N, Target_Type);
|
|
end if;
|
|
|
|
return;
|
|
end if;
|
|
|
|
-- The expression may be foldable but not static
|
|
|
|
Set_Is_Static_Expression (N, Stat);
|
|
|
|
if Is_Out_Of_Range (N, Etype (N)) then
|
|
Out_Of_Range (N);
|
|
end if;
|
|
end Eval_Qualified_Expression;
|
|
|
|
-----------------------
|
|
-- Eval_Real_Literal --
|
|
-----------------------
|
|
|
|
-- Numeric literals are static (RM 4.9(1)), and have already been marked
|
|
-- as static by the analyzer. The reason we did it that early is to allow
|
|
-- the possibility of turning off the Is_Static_Expression flag after
|
|
-- analysis, but before resolution, when integer literals are generated
|
|
-- in the expander that do not correspond to static expressions.
|
|
|
|
procedure Eval_Real_Literal (N : Node_Id) is
|
|
begin
|
|
-- If the literal appears in a non-expression context, then it is
|
|
-- certainly appearing in a non-static context, so check it.
|
|
|
|
if Nkind (Parent (N)) not in N_Subexpr then
|
|
Check_Non_Static_Context (N);
|
|
end if;
|
|
|
|
end Eval_Real_Literal;
|
|
|
|
------------------------
|
|
-- Eval_Relational_Op --
|
|
------------------------
|
|
|
|
-- Relational operations are static functions, so the result is static
|
|
-- if both operands are static (RM 4.9(7), 4.9(20)).
|
|
|
|
procedure Eval_Relational_Op (N : Node_Id) is
|
|
Left : constant Node_Id := Left_Opnd (N);
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
Typ : constant Entity_Id := Etype (Left);
|
|
Result : Boolean;
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
|
|
begin
|
|
-- One special case to deal with first. If we can tell that
|
|
-- the result will be false because the lengths of one or
|
|
-- more index subtypes are compile time known and different,
|
|
-- then we can replace the entire result by False. We only
|
|
-- do this for one dimensional arrays, because the case of
|
|
-- multi-dimensional arrays is rare and too much trouble!
|
|
|
|
if Is_Array_Type (Typ)
|
|
and then Number_Dimensions (Typ) = 1
|
|
and then (Nkind (N) = N_Op_Eq
|
|
or else Nkind (N) = N_Op_Ne)
|
|
then
|
|
if Raises_Constraint_Error (Left)
|
|
or else Raises_Constraint_Error (Right)
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
declare
|
|
procedure Get_Static_Length (Op : Node_Id; Len : out Uint);
|
|
-- If Op is an expression for a constrained array with a
|
|
-- known at compile time length, then Len is set to this
|
|
-- (non-negative length). Otherwise Len is set to minus 1.
|
|
|
|
-----------------------
|
|
-- Get_Static_Length --
|
|
-----------------------
|
|
|
|
procedure Get_Static_Length (Op : Node_Id; Len : out Uint) is
|
|
T : Entity_Id;
|
|
|
|
begin
|
|
if Nkind (Op) = N_String_Literal then
|
|
Len := UI_From_Int (String_Length (Strval (Op)));
|
|
|
|
elsif not Is_Constrained (Etype (Op)) then
|
|
Len := Uint_Minus_1;
|
|
|
|
else
|
|
T := Etype (First_Index (Etype (Op)));
|
|
|
|
if Is_Discrete_Type (T)
|
|
and then
|
|
Compile_Time_Known_Value (Type_Low_Bound (T))
|
|
and then
|
|
Compile_Time_Known_Value (Type_High_Bound (T))
|
|
then
|
|
Len := UI_Max (Uint_0,
|
|
Expr_Value (Type_High_Bound (T)) -
|
|
Expr_Value (Type_Low_Bound (T)) + 1);
|
|
else
|
|
Len := Uint_Minus_1;
|
|
end if;
|
|
end if;
|
|
end Get_Static_Length;
|
|
|
|
Len_L : Uint;
|
|
Len_R : Uint;
|
|
|
|
begin
|
|
Get_Static_Length (Left, Len_L);
|
|
Get_Static_Length (Right, Len_R);
|
|
|
|
if Len_L /= Uint_Minus_1
|
|
and then Len_R /= Uint_Minus_1
|
|
and then Len_L /= Len_R
|
|
then
|
|
Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False);
|
|
Warn_On_Known_Condition (N);
|
|
return;
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
-- Can only fold if type is scalar (don't fold string ops)
|
|
|
|
if not Is_Scalar_Type (Typ) then
|
|
Check_Non_Static_Context (Left);
|
|
Check_Non_Static_Context (Right);
|
|
return;
|
|
end if;
|
|
|
|
-- If not foldable we are done
|
|
|
|
Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold);
|
|
|
|
if not Fold then
|
|
return;
|
|
end if;
|
|
|
|
-- Integer and Enumeration (discrete) type cases
|
|
|
|
if Is_Discrete_Type (Typ) then
|
|
declare
|
|
Left_Int : constant Uint := Expr_Value (Left);
|
|
Right_Int : constant Uint := Expr_Value (Right);
|
|
|
|
begin
|
|
case Nkind (N) is
|
|
when N_Op_Eq => Result := Left_Int = Right_Int;
|
|
when N_Op_Ne => Result := Left_Int /= Right_Int;
|
|
when N_Op_Lt => Result := Left_Int < Right_Int;
|
|
when N_Op_Le => Result := Left_Int <= Right_Int;
|
|
when N_Op_Gt => Result := Left_Int > Right_Int;
|
|
when N_Op_Ge => Result := Left_Int >= Right_Int;
|
|
|
|
when others =>
|
|
raise Program_Error;
|
|
end case;
|
|
|
|
Fold_Uint (N, Test (Result), Stat);
|
|
end;
|
|
|
|
-- Real type case
|
|
|
|
else
|
|
pragma Assert (Is_Real_Type (Typ));
|
|
|
|
declare
|
|
Left_Real : constant Ureal := Expr_Value_R (Left);
|
|
Right_Real : constant Ureal := Expr_Value_R (Right);
|
|
|
|
begin
|
|
case Nkind (N) is
|
|
when N_Op_Eq => Result := (Left_Real = Right_Real);
|
|
when N_Op_Ne => Result := (Left_Real /= Right_Real);
|
|
when N_Op_Lt => Result := (Left_Real < Right_Real);
|
|
when N_Op_Le => Result := (Left_Real <= Right_Real);
|
|
when N_Op_Gt => Result := (Left_Real > Right_Real);
|
|
when N_Op_Ge => Result := (Left_Real >= Right_Real);
|
|
|
|
when others =>
|
|
raise Program_Error;
|
|
end case;
|
|
|
|
Fold_Uint (N, Test (Result), Stat);
|
|
end;
|
|
end if;
|
|
|
|
Warn_On_Known_Condition (N);
|
|
end Eval_Relational_Op;
|
|
|
|
----------------
|
|
-- Eval_Shift --
|
|
----------------
|
|
|
|
-- Shift operations are intrinsic operations that can never be static,
|
|
-- so the only processing required is to perform the required check for
|
|
-- a non static context for the two operands.
|
|
|
|
-- Actually we could do some compile time evaluation here some time ???
|
|
|
|
procedure Eval_Shift (N : Node_Id) is
|
|
begin
|
|
Check_Non_Static_Context (Left_Opnd (N));
|
|
Check_Non_Static_Context (Right_Opnd (N));
|
|
end Eval_Shift;
|
|
|
|
------------------------
|
|
-- Eval_Short_Circuit --
|
|
------------------------
|
|
|
|
-- A short circuit operation is potentially static if both operands
|
|
-- are potentially static (RM 4.9 (13))
|
|
|
|
procedure Eval_Short_Circuit (N : Node_Id) is
|
|
Kind : constant Node_Kind := Nkind (N);
|
|
Left : constant Node_Id := Left_Opnd (N);
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
Left_Int : Uint;
|
|
Rstat : constant Boolean :=
|
|
Is_Static_Expression (Left)
|
|
and then Is_Static_Expression (Right);
|
|
|
|
begin
|
|
-- Short circuit operations are never static in Ada 83
|
|
|
|
if Ada_Version = Ada_83
|
|
and then Comes_From_Source (N)
|
|
then
|
|
Check_Non_Static_Context (Left);
|
|
Check_Non_Static_Context (Right);
|
|
return;
|
|
end if;
|
|
|
|
-- Now look at the operands, we can't quite use the normal call to
|
|
-- Test_Expression_Is_Foldable here because short circuit operations
|
|
-- are a special case, they can still be foldable, even if the right
|
|
-- operand raises constraint error.
|
|
|
|
-- If either operand is Any_Type, just propagate to result and
|
|
-- do not try to fold, this prevents cascaded errors.
|
|
|
|
if Etype (Left) = Any_Type or else Etype (Right) = Any_Type then
|
|
Set_Etype (N, Any_Type);
|
|
return;
|
|
|
|
-- If left operand raises constraint error, then replace node N with
|
|
-- the raise constraint error node, and we are obviously not foldable.
|
|
-- Is_Static_Expression is set from the two operands in the normal way,
|
|
-- and we check the right operand if it is in a non-static context.
|
|
|
|
elsif Raises_Constraint_Error (Left) then
|
|
if not Rstat then
|
|
Check_Non_Static_Context (Right);
|
|
end if;
|
|
|
|
Rewrite_In_Raise_CE (N, Left);
|
|
Set_Is_Static_Expression (N, Rstat);
|
|
return;
|
|
|
|
-- If the result is not static, then we won't in any case fold
|
|
|
|
elsif not Rstat then
|
|
Check_Non_Static_Context (Left);
|
|
Check_Non_Static_Context (Right);
|
|
return;
|
|
end if;
|
|
|
|
-- Here the result is static, note that, unlike the normal processing
|
|
-- in Test_Expression_Is_Foldable, we did *not* check above to see if
|
|
-- the right operand raises constraint error, that's because it is not
|
|
-- significant if the left operand is decisive.
|
|
|
|
Set_Is_Static_Expression (N);
|
|
|
|
-- It does not matter if the right operand raises constraint error if
|
|
-- it will not be evaluated. So deal specially with the cases where
|
|
-- the right operand is not evaluated. Note that we will fold these
|
|
-- cases even if the right operand is non-static, which is fine, but
|
|
-- of course in these cases the result is not potentially static.
|
|
|
|
Left_Int := Expr_Value (Left);
|
|
|
|
if (Kind = N_And_Then and then Is_False (Left_Int))
|
|
or else (Kind = N_Or_Else and Is_True (Left_Int))
|
|
then
|
|
Fold_Uint (N, Left_Int, Rstat);
|
|
return;
|
|
end if;
|
|
|
|
-- If first operand not decisive, then it does matter if the right
|
|
-- operand raises constraint error, since it will be evaluated, so
|
|
-- we simply replace the node with the right operand. Note that this
|
|
-- properly propagates Is_Static_Expression and Raises_Constraint_Error
|
|
-- (both are set to True in Right).
|
|
|
|
if Raises_Constraint_Error (Right) then
|
|
Rewrite_In_Raise_CE (N, Right);
|
|
Check_Non_Static_Context (Left);
|
|
return;
|
|
end if;
|
|
|
|
-- Otherwise the result depends on the right operand
|
|
|
|
Fold_Uint (N, Expr_Value (Right), Rstat);
|
|
return;
|
|
end Eval_Short_Circuit;
|
|
|
|
----------------
|
|
-- Eval_Slice --
|
|
----------------
|
|
|
|
-- Slices can never be static, so the only processing required is to
|
|
-- check for non-static context if an explicit range is given.
|
|
|
|
procedure Eval_Slice (N : Node_Id) is
|
|
Drange : constant Node_Id := Discrete_Range (N);
|
|
|
|
begin
|
|
if Nkind (Drange) = N_Range then
|
|
Check_Non_Static_Context (Low_Bound (Drange));
|
|
Check_Non_Static_Context (High_Bound (Drange));
|
|
end if;
|
|
end Eval_Slice;
|
|
|
|
-------------------------
|
|
-- Eval_String_Literal --
|
|
-------------------------
|
|
|
|
procedure Eval_String_Literal (N : Node_Id) is
|
|
Typ : constant Entity_Id := Etype (N);
|
|
Bas : constant Entity_Id := Base_Type (Typ);
|
|
Xtp : Entity_Id;
|
|
Len : Nat;
|
|
Lo : Node_Id;
|
|
|
|
begin
|
|
-- Nothing to do if error type (handles cases like default expressions
|
|
-- or generics where we have not yet fully resolved the type)
|
|
|
|
if Bas = Any_Type or else Bas = Any_String then
|
|
return;
|
|
end if;
|
|
|
|
-- String literals are static if the subtype is static (RM 4.9(2)), so
|
|
-- reset the static expression flag (it was set unconditionally in
|
|
-- Analyze_String_Literal) if the subtype is non-static. We tell if
|
|
-- the subtype is static by looking at the lower bound.
|
|
|
|
if Ekind (Typ) = E_String_Literal_Subtype then
|
|
if not Is_OK_Static_Expression (String_Literal_Low_Bound (Typ)) then
|
|
Set_Is_Static_Expression (N, False);
|
|
return;
|
|
end if;
|
|
|
|
-- Here if Etype of string literal is normal Etype (not yet possible,
|
|
-- but may be possible in future!)
|
|
|
|
elsif not Is_OK_Static_Expression
|
|
(Type_Low_Bound (Etype (First_Index (Typ))))
|
|
then
|
|
Set_Is_Static_Expression (N, False);
|
|
return;
|
|
end if;
|
|
|
|
-- If original node was a type conversion, then result if non-static
|
|
|
|
if Nkind (Original_Node (N)) = N_Type_Conversion then
|
|
Set_Is_Static_Expression (N, False);
|
|
return;
|
|
end if;
|
|
|
|
-- Test for illegal Ada 95 cases. A string literal is illegal in
|
|
-- Ada 95 if its bounds are outside the index base type and this
|
|
-- index type is static. This can happen in only two ways. Either
|
|
-- the string literal is too long, or it is null, and the lower
|
|
-- bound is type'First. In either case it is the upper bound that
|
|
-- is out of range of the index type.
|
|
|
|
if Ada_Version >= Ada_95 then
|
|
if Root_Type (Bas) = Standard_String
|
|
or else
|
|
Root_Type (Bas) = Standard_Wide_String
|
|
then
|
|
Xtp := Standard_Positive;
|
|
else
|
|
Xtp := Etype (First_Index (Bas));
|
|
end if;
|
|
|
|
if Ekind (Typ) = E_String_Literal_Subtype then
|
|
Lo := String_Literal_Low_Bound (Typ);
|
|
else
|
|
Lo := Type_Low_Bound (Etype (First_Index (Typ)));
|
|
end if;
|
|
|
|
Len := String_Length (Strval (N));
|
|
|
|
if UI_From_Int (Len) > String_Type_Len (Bas) then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "string literal too long for}", CE_Length_Check_Failed,
|
|
Ent => Bas,
|
|
Typ => First_Subtype (Bas));
|
|
|
|
elsif Len = 0
|
|
and then not Is_Generic_Type (Xtp)
|
|
and then
|
|
Expr_Value (Lo) = Expr_Value (Type_Low_Bound (Base_Type (Xtp)))
|
|
then
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "null string literal not allowed for}",
|
|
CE_Length_Check_Failed,
|
|
Ent => Bas,
|
|
Typ => First_Subtype (Bas));
|
|
end if;
|
|
end if;
|
|
end Eval_String_Literal;
|
|
|
|
--------------------------
|
|
-- Eval_Type_Conversion --
|
|
--------------------------
|
|
|
|
-- A type conversion is potentially static if its subtype mark is for a
|
|
-- static scalar subtype, and its operand expression is potentially static
|
|
-- (RM 4.9 (10))
|
|
|
|
procedure Eval_Type_Conversion (N : Node_Id) is
|
|
Operand : constant Node_Id := Expression (N);
|
|
Source_Type : constant Entity_Id := Etype (Operand);
|
|
Target_Type : constant Entity_Id := Etype (N);
|
|
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
|
|
function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean;
|
|
-- Returns true if type T is an integer type, or if it is a
|
|
-- fixed-point type to be treated as an integer (i.e. the flag
|
|
-- Conversion_OK is set on the conversion node).
|
|
|
|
function To_Be_Treated_As_Real (T : Entity_Id) return Boolean;
|
|
-- Returns true if type T is a floating-point type, or if it is a
|
|
-- fixed-point type that is not to be treated as an integer (i.e. the
|
|
-- flag Conversion_OK is not set on the conversion node).
|
|
|
|
------------------------------
|
|
-- To_Be_Treated_As_Integer --
|
|
------------------------------
|
|
|
|
function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean is
|
|
begin
|
|
return
|
|
Is_Integer_Type (T)
|
|
or else (Is_Fixed_Point_Type (T) and then Conversion_OK (N));
|
|
end To_Be_Treated_As_Integer;
|
|
|
|
---------------------------
|
|
-- To_Be_Treated_As_Real --
|
|
---------------------------
|
|
|
|
function To_Be_Treated_As_Real (T : Entity_Id) return Boolean is
|
|
begin
|
|
return
|
|
Is_Floating_Point_Type (T)
|
|
or else (Is_Fixed_Point_Type (T) and then not Conversion_OK (N));
|
|
end To_Be_Treated_As_Real;
|
|
|
|
-- Start of processing for Eval_Type_Conversion
|
|
|
|
begin
|
|
-- Cannot fold if target type is non-static or if semantic error.
|
|
|
|
if not Is_Static_Subtype (Target_Type) then
|
|
Check_Non_Static_Context (Operand);
|
|
return;
|
|
|
|
elsif Error_Posted (N) then
|
|
return;
|
|
end if;
|
|
|
|
-- If not foldable we are done
|
|
|
|
Test_Expression_Is_Foldable (N, Operand, Stat, Fold);
|
|
|
|
if not Fold then
|
|
return;
|
|
|
|
-- Don't try fold if target type has constraint error bounds
|
|
|
|
elsif not Is_OK_Static_Subtype (Target_Type) then
|
|
Set_Raises_Constraint_Error (N);
|
|
return;
|
|
end if;
|
|
|
|
-- Remaining processing depends on operand types. Note that in the
|
|
-- following type test, fixed-point counts as real unless the flag
|
|
-- Conversion_OK is set, in which case it counts as integer.
|
|
|
|
-- Fold conversion, case of string type. The result is not static.
|
|
|
|
if Is_String_Type (Target_Type) then
|
|
Fold_Str (N, Strval (Get_String_Val (Operand)), False);
|
|
|
|
return;
|
|
|
|
-- Fold conversion, case of integer target type
|
|
|
|
elsif To_Be_Treated_As_Integer (Target_Type) then
|
|
declare
|
|
Result : Uint;
|
|
|
|
begin
|
|
-- Integer to integer conversion
|
|
|
|
if To_Be_Treated_As_Integer (Source_Type) then
|
|
Result := Expr_Value (Operand);
|
|
|
|
-- Real to integer conversion
|
|
|
|
else
|
|
Result := UR_To_Uint (Expr_Value_R (Operand));
|
|
end if;
|
|
|
|
-- If fixed-point type (Conversion_OK must be set), then the
|
|
-- result is logically an integer, but we must replace the
|
|
-- conversion with the corresponding real literal, since the
|
|
-- type from a semantic point of view is still fixed-point.
|
|
|
|
if Is_Fixed_Point_Type (Target_Type) then
|
|
Fold_Ureal
|
|
(N, UR_From_Uint (Result) * Small_Value (Target_Type), Stat);
|
|
|
|
-- Otherwise result is integer literal
|
|
|
|
else
|
|
Fold_Uint (N, Result, Stat);
|
|
end if;
|
|
end;
|
|
|
|
-- Fold conversion, case of real target type
|
|
|
|
elsif To_Be_Treated_As_Real (Target_Type) then
|
|
declare
|
|
Result : Ureal;
|
|
|
|
begin
|
|
if To_Be_Treated_As_Real (Source_Type) then
|
|
Result := Expr_Value_R (Operand);
|
|
else
|
|
Result := UR_From_Uint (Expr_Value (Operand));
|
|
end if;
|
|
|
|
Fold_Ureal (N, Result, Stat);
|
|
end;
|
|
|
|
-- Enumeration types
|
|
|
|
else
|
|
Fold_Uint (N, Expr_Value (Operand), Stat);
|
|
end if;
|
|
|
|
if Is_Out_Of_Range (N, Etype (N)) then
|
|
Out_Of_Range (N);
|
|
end if;
|
|
|
|
end Eval_Type_Conversion;
|
|
|
|
-------------------
|
|
-- Eval_Unary_Op --
|
|
-------------------
|
|
|
|
-- Predefined unary operators are static functions (RM 4.9(20)) and thus
|
|
-- are potentially static if the operand is potentially static (RM 4.9(7))
|
|
|
|
procedure Eval_Unary_Op (N : Node_Id) is
|
|
Right : constant Node_Id := Right_Opnd (N);
|
|
Stat : Boolean;
|
|
Fold : Boolean;
|
|
|
|
begin
|
|
-- If not foldable we are done
|
|
|
|
Test_Expression_Is_Foldable (N, Right, Stat, Fold);
|
|
|
|
if not Fold then
|
|
return;
|
|
end if;
|
|
|
|
-- Fold for integer case
|
|
|
|
if Is_Integer_Type (Etype (N)) then
|
|
declare
|
|
Rint : constant Uint := Expr_Value (Right);
|
|
Result : Uint;
|
|
|
|
begin
|
|
-- In the case of modular unary plus and abs there is no need
|
|
-- to adjust the result of the operation since if the original
|
|
-- operand was in bounds the result will be in the bounds of the
|
|
-- modular type. However, in the case of modular unary minus the
|
|
-- result may go out of the bounds of the modular type and needs
|
|
-- adjustment.
|
|
|
|
if Nkind (N) = N_Op_Plus then
|
|
Result := Rint;
|
|
|
|
elsif Nkind (N) = N_Op_Minus then
|
|
if Is_Modular_Integer_Type (Etype (N)) then
|
|
Result := (-Rint) mod Modulus (Etype (N));
|
|
else
|
|
Result := (-Rint);
|
|
end if;
|
|
|
|
else
|
|
pragma Assert (Nkind (N) = N_Op_Abs);
|
|
Result := abs Rint;
|
|
end if;
|
|
|
|
Fold_Uint (N, Result, Stat);
|
|
end;
|
|
|
|
-- Fold for real case
|
|
|
|
elsif Is_Real_Type (Etype (N)) then
|
|
declare
|
|
Rreal : constant Ureal := Expr_Value_R (Right);
|
|
Result : Ureal;
|
|
|
|
begin
|
|
if Nkind (N) = N_Op_Plus then
|
|
Result := Rreal;
|
|
|
|
elsif Nkind (N) = N_Op_Minus then
|
|
Result := UR_Negate (Rreal);
|
|
|
|
else
|
|
pragma Assert (Nkind (N) = N_Op_Abs);
|
|
Result := abs Rreal;
|
|
end if;
|
|
|
|
Fold_Ureal (N, Result, Stat);
|
|
end;
|
|
end if;
|
|
end Eval_Unary_Op;
|
|
|
|
-------------------------------
|
|
-- Eval_Unchecked_Conversion --
|
|
-------------------------------
|
|
|
|
-- Unchecked conversions can never be static, so the only required
|
|
-- processing is to check for a non-static context for the operand.
|
|
|
|
procedure Eval_Unchecked_Conversion (N : Node_Id) is
|
|
begin
|
|
Check_Non_Static_Context (Expression (N));
|
|
end Eval_Unchecked_Conversion;
|
|
|
|
--------------------
|
|
-- Expr_Rep_Value --
|
|
--------------------
|
|
|
|
function Expr_Rep_Value (N : Node_Id) return Uint is
|
|
Kind : constant Node_Kind := Nkind (N);
|
|
Ent : Entity_Id;
|
|
|
|
begin
|
|
if Is_Entity_Name (N) then
|
|
Ent := Entity (N);
|
|
|
|
-- An enumeration literal that was either in the source or
|
|
-- created as a result of static evaluation.
|
|
|
|
if Ekind (Ent) = E_Enumeration_Literal then
|
|
return Enumeration_Rep (Ent);
|
|
|
|
-- A user defined static constant
|
|
|
|
else
|
|
pragma Assert (Ekind (Ent) = E_Constant);
|
|
return Expr_Rep_Value (Constant_Value (Ent));
|
|
end if;
|
|
|
|
-- An integer literal that was either in the source or created
|
|
-- as a result of static evaluation.
|
|
|
|
elsif Kind = N_Integer_Literal then
|
|
return Intval (N);
|
|
|
|
-- A real literal for a fixed-point type. This must be the fixed-point
|
|
-- case, either the literal is of a fixed-point type, or it is a bound
|
|
-- of a fixed-point type, with type universal real. In either case we
|
|
-- obtain the desired value from Corresponding_Integer_Value.
|
|
|
|
elsif Kind = N_Real_Literal then
|
|
pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N))));
|
|
return Corresponding_Integer_Value (N);
|
|
|
|
-- Peculiar VMS case, if we have xxx'Null_Parameter, return zero
|
|
|
|
elsif Kind = N_Attribute_Reference
|
|
and then Attribute_Name (N) = Name_Null_Parameter
|
|
then
|
|
return Uint_0;
|
|
|
|
-- Otherwise must be character literal
|
|
|
|
else
|
|
pragma Assert (Kind = N_Character_Literal);
|
|
Ent := Entity (N);
|
|
|
|
-- Since Character literals of type Standard.Character don't
|
|
-- have any defining character literals built for them, they
|
|
-- do not have their Entity set, so just use their Char
|
|
-- code. Otherwise for user-defined character literals use
|
|
-- their Pos value as usual which is the same as the Rep value.
|
|
|
|
if No (Ent) then
|
|
return UI_From_Int (Int (Char_Literal_Value (N)));
|
|
else
|
|
return Enumeration_Rep (Ent);
|
|
end if;
|
|
end if;
|
|
end Expr_Rep_Value;
|
|
|
|
----------------
|
|
-- Expr_Value --
|
|
----------------
|
|
|
|
function Expr_Value (N : Node_Id) return Uint is
|
|
Kind : constant Node_Kind := Nkind (N);
|
|
CV_Ent : CV_Entry renames CV_Cache (Nat (N) mod CV_Cache_Size);
|
|
Ent : Entity_Id;
|
|
Val : Uint;
|
|
|
|
begin
|
|
-- If already in cache, then we know it's compile time known and
|
|
-- we can return the value that was previously stored in the cache
|
|
-- since compile time known values cannot change :-)
|
|
|
|
if CV_Ent.N = N then
|
|
return CV_Ent.V;
|
|
end if;
|
|
|
|
-- Otherwise proceed to test value
|
|
|
|
if Is_Entity_Name (N) then
|
|
Ent := Entity (N);
|
|
|
|
-- An enumeration literal that was either in the source or
|
|
-- created as a result of static evaluation.
|
|
|
|
if Ekind (Ent) = E_Enumeration_Literal then
|
|
Val := Enumeration_Pos (Ent);
|
|
|
|
-- A user defined static constant
|
|
|
|
else
|
|
pragma Assert (Ekind (Ent) = E_Constant);
|
|
Val := Expr_Value (Constant_Value (Ent));
|
|
end if;
|
|
|
|
-- An integer literal that was either in the source or created
|
|
-- as a result of static evaluation.
|
|
|
|
elsif Kind = N_Integer_Literal then
|
|
Val := Intval (N);
|
|
|
|
-- A real literal for a fixed-point type. This must be the fixed-point
|
|
-- case, either the literal is of a fixed-point type, or it is a bound
|
|
-- of a fixed-point type, with type universal real. In either case we
|
|
-- obtain the desired value from Corresponding_Integer_Value.
|
|
|
|
elsif Kind = N_Real_Literal then
|
|
|
|
pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N))));
|
|
Val := Corresponding_Integer_Value (N);
|
|
|
|
-- Peculiar VMS case, if we have xxx'Null_Parameter, return zero
|
|
|
|
elsif Kind = N_Attribute_Reference
|
|
and then Attribute_Name (N) = Name_Null_Parameter
|
|
then
|
|
Val := Uint_0;
|
|
|
|
-- Otherwise must be character literal
|
|
|
|
else
|
|
pragma Assert (Kind = N_Character_Literal);
|
|
Ent := Entity (N);
|
|
|
|
-- Since Character literals of type Standard.Character don't
|
|
-- have any defining character literals built for them, they
|
|
-- do not have their Entity set, so just use their Char
|
|
-- code. Otherwise for user-defined character literals use
|
|
-- their Pos value as usual.
|
|
|
|
if No (Ent) then
|
|
Val := UI_From_Int (Int (Char_Literal_Value (N)));
|
|
else
|
|
Val := Enumeration_Pos (Ent);
|
|
end if;
|
|
end if;
|
|
|
|
-- Come here with Val set to value to be returned, set cache
|
|
|
|
CV_Ent.N := N;
|
|
CV_Ent.V := Val;
|
|
return Val;
|
|
end Expr_Value;
|
|
|
|
------------------
|
|
-- Expr_Value_E --
|
|
------------------
|
|
|
|
function Expr_Value_E (N : Node_Id) return Entity_Id is
|
|
Ent : constant Entity_Id := Entity (N);
|
|
|
|
begin
|
|
if Ekind (Ent) = E_Enumeration_Literal then
|
|
return Ent;
|
|
else
|
|
pragma Assert (Ekind (Ent) = E_Constant);
|
|
return Expr_Value_E (Constant_Value (Ent));
|
|
end if;
|
|
end Expr_Value_E;
|
|
|
|
------------------
|
|
-- Expr_Value_R --
|
|
------------------
|
|
|
|
function Expr_Value_R (N : Node_Id) return Ureal is
|
|
Kind : constant Node_Kind := Nkind (N);
|
|
Ent : Entity_Id;
|
|
Expr : Node_Id;
|
|
|
|
begin
|
|
if Kind = N_Real_Literal then
|
|
return Realval (N);
|
|
|
|
elsif Kind = N_Identifier or else Kind = N_Expanded_Name then
|
|
Ent := Entity (N);
|
|
pragma Assert (Ekind (Ent) = E_Constant);
|
|
return Expr_Value_R (Constant_Value (Ent));
|
|
|
|
elsif Kind = N_Integer_Literal then
|
|
return UR_From_Uint (Expr_Value (N));
|
|
|
|
-- Strange case of VAX literals, which are at this stage transformed
|
|
-- into Vax_Type!x_To_y(IEEE_Literal). See Expand_N_Real_Literal in
|
|
-- Exp_Vfpt for further details.
|
|
|
|
elsif Vax_Float (Etype (N))
|
|
and then Nkind (N) = N_Unchecked_Type_Conversion
|
|
then
|
|
Expr := Expression (N);
|
|
|
|
if Nkind (Expr) = N_Function_Call
|
|
and then Present (Parameter_Associations (Expr))
|
|
then
|
|
Expr := First (Parameter_Associations (Expr));
|
|
|
|
if Nkind (Expr) = N_Real_Literal then
|
|
return Realval (Expr);
|
|
end if;
|
|
end if;
|
|
|
|
-- Peculiar VMS case, if we have xxx'Null_Parameter, return 0.0
|
|
|
|
elsif Kind = N_Attribute_Reference
|
|
and then Attribute_Name (N) = Name_Null_Parameter
|
|
then
|
|
return Ureal_0;
|
|
end if;
|
|
|
|
-- If we fall through, we have a node that cannot be interepreted
|
|
-- as a compile time constant. That is definitely an error.
|
|
|
|
raise Program_Error;
|
|
end Expr_Value_R;
|
|
|
|
------------------
|
|
-- Expr_Value_S --
|
|
------------------
|
|
|
|
function Expr_Value_S (N : Node_Id) return Node_Id is
|
|
begin
|
|
if Nkind (N) = N_String_Literal then
|
|
return N;
|
|
else
|
|
pragma Assert (Ekind (Entity (N)) = E_Constant);
|
|
return Expr_Value_S (Constant_Value (Entity (N)));
|
|
end if;
|
|
end Expr_Value_S;
|
|
|
|
--------------------------
|
|
-- Flag_Non_Static_Expr --
|
|
--------------------------
|
|
|
|
procedure Flag_Non_Static_Expr (Msg : String; Expr : Node_Id) is
|
|
begin
|
|
if Error_Posted (Expr) and then not All_Errors_Mode then
|
|
return;
|
|
else
|
|
Error_Msg_F (Msg, Expr);
|
|
Why_Not_Static (Expr);
|
|
end if;
|
|
end Flag_Non_Static_Expr;
|
|
|
|
--------------
|
|
-- Fold_Str --
|
|
--------------
|
|
|
|
procedure Fold_Str (N : Node_Id; Val : String_Id; Static : Boolean) is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Typ : constant Entity_Id := Etype (N);
|
|
|
|
begin
|
|
Rewrite (N, Make_String_Literal (Loc, Strval => Val));
|
|
|
|
-- We now have the literal with the right value, both the actual type
|
|
-- and the expected type of this literal are taken from the expression
|
|
-- that was evaluated.
|
|
|
|
Analyze (N);
|
|
Set_Is_Static_Expression (N, Static);
|
|
Set_Etype (N, Typ);
|
|
Resolve (N);
|
|
end Fold_Str;
|
|
|
|
---------------
|
|
-- Fold_Uint --
|
|
---------------
|
|
|
|
procedure Fold_Uint (N : Node_Id; Val : Uint; Static : Boolean) is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Typ : Entity_Id := Etype (N);
|
|
Ent : Entity_Id;
|
|
|
|
begin
|
|
-- If we are folding a named number, retain the entity in the
|
|
-- literal, for ASIS use.
|
|
|
|
if Is_Entity_Name (N)
|
|
and then Ekind (Entity (N)) = E_Named_Integer
|
|
then
|
|
Ent := Entity (N);
|
|
else
|
|
Ent := Empty;
|
|
end if;
|
|
|
|
if Is_Private_Type (Typ) then
|
|
Typ := Full_View (Typ);
|
|
end if;
|
|
|
|
-- For a result of type integer, subsitute an N_Integer_Literal node
|
|
-- for the result of the compile time evaluation of the expression.
|
|
|
|
if Is_Integer_Type (Typ) then
|
|
Rewrite (N, Make_Integer_Literal (Loc, Val));
|
|
Set_Original_Entity (N, Ent);
|
|
|
|
-- Otherwise we have an enumeration type, and we substitute either
|
|
-- an N_Identifier or N_Character_Literal to represent the enumeration
|
|
-- literal corresponding to the given value, which must always be in
|
|
-- range, because appropriate tests have already been made for this.
|
|
|
|
else pragma Assert (Is_Enumeration_Type (Typ));
|
|
Rewrite (N, Get_Enum_Lit_From_Pos (Etype (N), Val, Loc));
|
|
end if;
|
|
|
|
-- We now have the literal with the right value, both the actual type
|
|
-- and the expected type of this literal are taken from the expression
|
|
-- that was evaluated.
|
|
|
|
Analyze (N);
|
|
Set_Is_Static_Expression (N, Static);
|
|
Set_Etype (N, Typ);
|
|
Resolve (N);
|
|
end Fold_Uint;
|
|
|
|
----------------
|
|
-- Fold_Ureal --
|
|
----------------
|
|
|
|
procedure Fold_Ureal (N : Node_Id; Val : Ureal; Static : Boolean) is
|
|
Loc : constant Source_Ptr := Sloc (N);
|
|
Typ : constant Entity_Id := Etype (N);
|
|
Ent : Entity_Id;
|
|
|
|
begin
|
|
-- If we are folding a named number, retain the entity in the
|
|
-- literal, for ASIS use.
|
|
|
|
if Is_Entity_Name (N)
|
|
and then Ekind (Entity (N)) = E_Named_Real
|
|
then
|
|
Ent := Entity (N);
|
|
else
|
|
Ent := Empty;
|
|
end if;
|
|
|
|
Rewrite (N, Make_Real_Literal (Loc, Realval => Val));
|
|
Set_Original_Entity (N, Ent);
|
|
|
|
-- Both the actual and expected type comes from the original expression
|
|
|
|
Analyze (N);
|
|
Set_Is_Static_Expression (N, Static);
|
|
Set_Etype (N, Typ);
|
|
Resolve (N);
|
|
end Fold_Ureal;
|
|
|
|
---------------
|
|
-- From_Bits --
|
|
---------------
|
|
|
|
function From_Bits (B : Bits; T : Entity_Id) return Uint is
|
|
V : Uint := Uint_0;
|
|
|
|
begin
|
|
for J in 0 .. B'Last loop
|
|
if B (J) then
|
|
V := V + 2 ** J;
|
|
end if;
|
|
end loop;
|
|
|
|
if Non_Binary_Modulus (T) then
|
|
V := V mod Modulus (T);
|
|
end if;
|
|
|
|
return V;
|
|
end From_Bits;
|
|
|
|
--------------------
|
|
-- Get_String_Val --
|
|
--------------------
|
|
|
|
function Get_String_Val (N : Node_Id) return Node_Id is
|
|
begin
|
|
if Nkind (N) = N_String_Literal then
|
|
return N;
|
|
|
|
elsif Nkind (N) = N_Character_Literal then
|
|
return N;
|
|
|
|
else
|
|
pragma Assert (Is_Entity_Name (N));
|
|
return Get_String_Val (Constant_Value (Entity (N)));
|
|
end if;
|
|
end Get_String_Val;
|
|
|
|
----------------
|
|
-- Initialize --
|
|
----------------
|
|
|
|
procedure Initialize is
|
|
begin
|
|
CV_Cache := (others => (Node_High_Bound, Uint_0));
|
|
end Initialize;
|
|
|
|
--------------------
|
|
-- In_Subrange_Of --
|
|
--------------------
|
|
|
|
function In_Subrange_Of
|
|
(T1 : Entity_Id;
|
|
T2 : Entity_Id;
|
|
Fixed_Int : Boolean := False)
|
|
return Boolean
|
|
is
|
|
L1 : Node_Id;
|
|
H1 : Node_Id;
|
|
|
|
L2 : Node_Id;
|
|
H2 : Node_Id;
|
|
|
|
begin
|
|
if T1 = T2 or else Is_Subtype_Of (T1, T2) then
|
|
return True;
|
|
|
|
-- Never in range if both types are not scalar. Don't know if this can
|
|
-- actually happen, but just in case.
|
|
|
|
elsif not Is_Scalar_Type (T1) or else not Is_Scalar_Type (T1) then
|
|
return False;
|
|
|
|
else
|
|
L1 := Type_Low_Bound (T1);
|
|
H1 := Type_High_Bound (T1);
|
|
|
|
L2 := Type_Low_Bound (T2);
|
|
H2 := Type_High_Bound (T2);
|
|
|
|
-- Check bounds to see if comparison possible at compile time
|
|
|
|
if Compile_Time_Compare (L1, L2) in Compare_GE
|
|
and then
|
|
Compile_Time_Compare (H1, H2) in Compare_LE
|
|
then
|
|
return True;
|
|
end if;
|
|
|
|
-- If bounds not comparable at compile time, then the bounds of T2
|
|
-- must be compile time known or we cannot answer the query.
|
|
|
|
if not Compile_Time_Known_Value (L2)
|
|
or else not Compile_Time_Known_Value (H2)
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
-- If the bounds of T1 are know at compile time then use these
|
|
-- ones, otherwise use the bounds of the base type (which are of
|
|
-- course always static).
|
|
|
|
if not Compile_Time_Known_Value (L1) then
|
|
L1 := Type_Low_Bound (Base_Type (T1));
|
|
end if;
|
|
|
|
if not Compile_Time_Known_Value (H1) then
|
|
H1 := Type_High_Bound (Base_Type (T1));
|
|
end if;
|
|
|
|
-- Fixed point types should be considered as such only if
|
|
-- flag Fixed_Int is set to False.
|
|
|
|
if Is_Floating_Point_Type (T1) or else Is_Floating_Point_Type (T2)
|
|
or else (Is_Fixed_Point_Type (T1) and then not Fixed_Int)
|
|
or else (Is_Fixed_Point_Type (T2) and then not Fixed_Int)
|
|
then
|
|
return
|
|
Expr_Value_R (L2) <= Expr_Value_R (L1)
|
|
and then
|
|
Expr_Value_R (H2) >= Expr_Value_R (H1);
|
|
|
|
else
|
|
return
|
|
Expr_Value (L2) <= Expr_Value (L1)
|
|
and then
|
|
Expr_Value (H2) >= Expr_Value (H1);
|
|
|
|
end if;
|
|
end if;
|
|
|
|
-- If any exception occurs, it means that we have some bug in the compiler
|
|
-- possibly triggered by a previous error, or by some unforseen 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 the answer in this case after all.
|
|
|
|
exception
|
|
when others =>
|
|
|
|
-- Debug flag K disables this behavior (useful for debugging)
|
|
|
|
if Debug_Flag_K then
|
|
raise;
|
|
else
|
|
return False;
|
|
end if;
|
|
end In_Subrange_Of;
|
|
|
|
-----------------
|
|
-- Is_In_Range --
|
|
-----------------
|
|
|
|
function Is_In_Range
|
|
(N : Node_Id;
|
|
Typ : Entity_Id;
|
|
Fixed_Int : Boolean := False;
|
|
Int_Real : Boolean := False)
|
|
return Boolean
|
|
is
|
|
Val : Uint;
|
|
Valr : Ureal;
|
|
|
|
begin
|
|
-- Universal types have no range limits, so always in range.
|
|
|
|
if Typ = Universal_Integer or else Typ = Universal_Real then
|
|
return True;
|
|
|
|
-- Never in range if not scalar type. Don't know if this can
|
|
-- actually happen, but our spec allows it, so we must check!
|
|
|
|
elsif not Is_Scalar_Type (Typ) then
|
|
return False;
|
|
|
|
-- Never in range unless we have a compile time known value.
|
|
|
|
elsif not Compile_Time_Known_Value (N) then
|
|
return False;
|
|
|
|
else
|
|
declare
|
|
Lo : constant Node_Id := Type_Low_Bound (Typ);
|
|
Hi : constant Node_Id := Type_High_Bound (Typ);
|
|
LB_Known : constant Boolean := Compile_Time_Known_Value (Lo);
|
|
UB_Known : constant Boolean := Compile_Time_Known_Value (Hi);
|
|
|
|
begin
|
|
-- Fixed point types should be considered as such only in
|
|
-- flag Fixed_Int is set to False.
|
|
|
|
if Is_Floating_Point_Type (Typ)
|
|
or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int)
|
|
or else Int_Real
|
|
then
|
|
Valr := Expr_Value_R (N);
|
|
|
|
if LB_Known and then Valr >= Expr_Value_R (Lo)
|
|
and then UB_Known and then Valr <= Expr_Value_R (Hi)
|
|
then
|
|
return True;
|
|
else
|
|
return False;
|
|
end if;
|
|
|
|
else
|
|
Val := Expr_Value (N);
|
|
|
|
if LB_Known and then Val >= Expr_Value (Lo)
|
|
and then UB_Known and then Val <= Expr_Value (Hi)
|
|
then
|
|
return True;
|
|
else
|
|
return False;
|
|
end if;
|
|
end if;
|
|
end;
|
|
end if;
|
|
end Is_In_Range;
|
|
|
|
-------------------
|
|
-- Is_Null_Range --
|
|
-------------------
|
|
|
|
function Is_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is
|
|
Typ : constant Entity_Id := Etype (Lo);
|
|
|
|
begin
|
|
if not Compile_Time_Known_Value (Lo)
|
|
or else not Compile_Time_Known_Value (Hi)
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
if Is_Discrete_Type (Typ) then
|
|
return Expr_Value (Lo) > Expr_Value (Hi);
|
|
|
|
else
|
|
pragma Assert (Is_Real_Type (Typ));
|
|
return Expr_Value_R (Lo) > Expr_Value_R (Hi);
|
|
end if;
|
|
end Is_Null_Range;
|
|
|
|
-----------------------------
|
|
-- Is_OK_Static_Expression --
|
|
-----------------------------
|
|
|
|
function Is_OK_Static_Expression (N : Node_Id) return Boolean is
|
|
begin
|
|
return Is_Static_Expression (N)
|
|
and then not Raises_Constraint_Error (N);
|
|
end Is_OK_Static_Expression;
|
|
|
|
------------------------
|
|
-- Is_OK_Static_Range --
|
|
------------------------
|
|
|
|
-- A static range is a range whose bounds are static expressions, or a
|
|
-- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
|
|
-- We have already converted range attribute references, so we get the
|
|
-- "or" part of this rule without needing a special test.
|
|
|
|
function Is_OK_Static_Range (N : Node_Id) return Boolean is
|
|
begin
|
|
return Is_OK_Static_Expression (Low_Bound (N))
|
|
and then Is_OK_Static_Expression (High_Bound (N));
|
|
end Is_OK_Static_Range;
|
|
|
|
--------------------------
|
|
-- Is_OK_Static_Subtype --
|
|
--------------------------
|
|
|
|
-- Determines if Typ is a static subtype as defined in (RM 4.9(26))
|
|
-- where neither bound raises constraint error when evaluated.
|
|
|
|
function Is_OK_Static_Subtype (Typ : Entity_Id) return Boolean is
|
|
Base_T : constant Entity_Id := Base_Type (Typ);
|
|
Anc_Subt : Entity_Id;
|
|
|
|
begin
|
|
-- First a quick check on the non static subtype flag. As described
|
|
-- in further detail in Einfo, this flag is not decisive in all cases,
|
|
-- but if it is set, then the subtype is definitely non-static.
|
|
|
|
if Is_Non_Static_Subtype (Typ) then
|
|
return False;
|
|
end if;
|
|
|
|
Anc_Subt := Ancestor_Subtype (Typ);
|
|
|
|
if Anc_Subt = Empty then
|
|
Anc_Subt := Base_T;
|
|
end if;
|
|
|
|
if Is_Generic_Type (Root_Type (Base_T))
|
|
or else Is_Generic_Actual_Type (Base_T)
|
|
then
|
|
return False;
|
|
|
|
-- String types
|
|
|
|
elsif Is_String_Type (Typ) then
|
|
return
|
|
Ekind (Typ) = E_String_Literal_Subtype
|
|
or else
|
|
(Is_OK_Static_Subtype (Component_Type (Typ))
|
|
and then Is_OK_Static_Subtype (Etype (First_Index (Typ))));
|
|
|
|
-- Scalar types
|
|
|
|
elsif Is_Scalar_Type (Typ) then
|
|
if Base_T = Typ then
|
|
return True;
|
|
|
|
else
|
|
-- Scalar_Range (Typ) might be an N_Subtype_Indication, so
|
|
-- use Get_Type_Low,High_Bound.
|
|
|
|
return Is_OK_Static_Subtype (Anc_Subt)
|
|
and then Is_OK_Static_Expression (Type_Low_Bound (Typ))
|
|
and then Is_OK_Static_Expression (Type_High_Bound (Typ));
|
|
end if;
|
|
|
|
-- Types other than string and scalar types are never static
|
|
|
|
else
|
|
return False;
|
|
end if;
|
|
end Is_OK_Static_Subtype;
|
|
|
|
---------------------
|
|
-- Is_Out_Of_Range --
|
|
---------------------
|
|
|
|
function Is_Out_Of_Range
|
|
(N : Node_Id;
|
|
Typ : Entity_Id;
|
|
Fixed_Int : Boolean := False;
|
|
Int_Real : Boolean := False)
|
|
return Boolean
|
|
is
|
|
Val : Uint;
|
|
Valr : Ureal;
|
|
|
|
begin
|
|
-- Universal types have no range limits, so always in range.
|
|
|
|
if Typ = Universal_Integer or else Typ = Universal_Real then
|
|
return False;
|
|
|
|
-- Never out of range if not scalar type. Don't know if this can
|
|
-- actually happen, but our spec allows it, so we must check!
|
|
|
|
elsif not Is_Scalar_Type (Typ) then
|
|
return False;
|
|
|
|
-- Never out of range if this is a generic type, since the bounds
|
|
-- of generic types are junk. Note that if we only checked for
|
|
-- static expressions (instead of compile time known values) below,
|
|
-- we would not need this check, because values of a generic type
|
|
-- can never be static, but they can be known at compile time.
|
|
|
|
elsif Is_Generic_Type (Typ) then
|
|
return False;
|
|
|
|
-- Never out of range unless we have a compile time known value
|
|
|
|
elsif not Compile_Time_Known_Value (N) then
|
|
return False;
|
|
|
|
else
|
|
declare
|
|
Lo : constant Node_Id := Type_Low_Bound (Typ);
|
|
Hi : constant Node_Id := Type_High_Bound (Typ);
|
|
LB_Known : constant Boolean := Compile_Time_Known_Value (Lo);
|
|
UB_Known : constant Boolean := Compile_Time_Known_Value (Hi);
|
|
|
|
begin
|
|
-- Real types (note that fixed-point types are not treated
|
|
-- as being of a real type if the flag Fixed_Int is set,
|
|
-- since in that case they are regarded as integer types).
|
|
|
|
if Is_Floating_Point_Type (Typ)
|
|
or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int)
|
|
or else Int_Real
|
|
then
|
|
Valr := Expr_Value_R (N);
|
|
|
|
if LB_Known and then Valr < Expr_Value_R (Lo) then
|
|
return True;
|
|
|
|
elsif UB_Known and then Expr_Value_R (Hi) < Valr then
|
|
return True;
|
|
|
|
else
|
|
return False;
|
|
end if;
|
|
|
|
else
|
|
Val := Expr_Value (N);
|
|
|
|
if LB_Known and then Val < Expr_Value (Lo) then
|
|
return True;
|
|
|
|
elsif UB_Known and then Expr_Value (Hi) < Val then
|
|
return True;
|
|
|
|
else
|
|
return False;
|
|
end if;
|
|
end if;
|
|
end;
|
|
end if;
|
|
end Is_Out_Of_Range;
|
|
|
|
---------------------
|
|
-- Is_Static_Range --
|
|
---------------------
|
|
|
|
-- A static range is a range whose bounds are static expressions, or a
|
|
-- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)).
|
|
-- We have already converted range attribute references, so we get the
|
|
-- "or" part of this rule without needing a special test.
|
|
|
|
function Is_Static_Range (N : Node_Id) return Boolean is
|
|
begin
|
|
return Is_Static_Expression (Low_Bound (N))
|
|
and then Is_Static_Expression (High_Bound (N));
|
|
end Is_Static_Range;
|
|
|
|
-----------------------
|
|
-- Is_Static_Subtype --
|
|
-----------------------
|
|
|
|
-- Determines if Typ is a static subtype as defined in (RM 4.9(26)).
|
|
|
|
function Is_Static_Subtype (Typ : Entity_Id) return Boolean is
|
|
Base_T : constant Entity_Id := Base_Type (Typ);
|
|
Anc_Subt : Entity_Id;
|
|
|
|
begin
|
|
-- First a quick check on the non static subtype flag. As described
|
|
-- in further detail in Einfo, this flag is not decisive in all cases,
|
|
-- but if it is set, then the subtype is definitely non-static.
|
|
|
|
if Is_Non_Static_Subtype (Typ) then
|
|
return False;
|
|
end if;
|
|
|
|
Anc_Subt := Ancestor_Subtype (Typ);
|
|
|
|
if Anc_Subt = Empty then
|
|
Anc_Subt := Base_T;
|
|
end if;
|
|
|
|
if Is_Generic_Type (Root_Type (Base_T))
|
|
or else Is_Generic_Actual_Type (Base_T)
|
|
then
|
|
return False;
|
|
|
|
-- String types
|
|
|
|
elsif Is_String_Type (Typ) then
|
|
return
|
|
Ekind (Typ) = E_String_Literal_Subtype
|
|
or else
|
|
(Is_Static_Subtype (Component_Type (Typ))
|
|
and then Is_Static_Subtype (Etype (First_Index (Typ))));
|
|
|
|
-- Scalar types
|
|
|
|
elsif Is_Scalar_Type (Typ) then
|
|
if Base_T = Typ then
|
|
return True;
|
|
|
|
else
|
|
return Is_Static_Subtype (Anc_Subt)
|
|
and then Is_Static_Expression (Type_Low_Bound (Typ))
|
|
and then Is_Static_Expression (Type_High_Bound (Typ));
|
|
end if;
|
|
|
|
-- Types other than string and scalar types are never static
|
|
|
|
else
|
|
return False;
|
|
end if;
|
|
end Is_Static_Subtype;
|
|
|
|
--------------------
|
|
-- Not_Null_Range --
|
|
--------------------
|
|
|
|
function Not_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is
|
|
Typ : constant Entity_Id := Etype (Lo);
|
|
|
|
begin
|
|
if not Compile_Time_Known_Value (Lo)
|
|
or else not Compile_Time_Known_Value (Hi)
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
if Is_Discrete_Type (Typ) then
|
|
return Expr_Value (Lo) <= Expr_Value (Hi);
|
|
|
|
else
|
|
pragma Assert (Is_Real_Type (Typ));
|
|
|
|
return Expr_Value_R (Lo) <= Expr_Value_R (Hi);
|
|
end if;
|
|
end Not_Null_Range;
|
|
|
|
-------------
|
|
-- OK_Bits --
|
|
-------------
|
|
|
|
function OK_Bits (N : Node_Id; Bits : Uint) return Boolean is
|
|
begin
|
|
-- We allow a maximum of 500,000 bits which seems a reasonable limit
|
|
|
|
if Bits < 500_000 then
|
|
return True;
|
|
|
|
else
|
|
Error_Msg_N ("static value too large, capacity exceeded", N);
|
|
return False;
|
|
end if;
|
|
end OK_Bits;
|
|
|
|
------------------
|
|
-- Out_Of_Range --
|
|
------------------
|
|
|
|
procedure Out_Of_Range (N : Node_Id) is
|
|
begin
|
|
-- If we have the static expression case, then this is an illegality
|
|
-- in Ada 95 mode, except that in an instance, we never generate an
|
|
-- error (if the error is legitimate, it was already diagnosed in
|
|
-- the template). The expression to compute the length of a packed
|
|
-- array is attached to the array type itself, and deserves a separate
|
|
-- message.
|
|
|
|
if Is_Static_Expression (N)
|
|
and then not In_Instance
|
|
and then not In_Inlined_Body
|
|
and then Ada_Version >= Ada_95
|
|
then
|
|
if Nkind (Parent (N)) = N_Defining_Identifier
|
|
and then Is_Array_Type (Parent (N))
|
|
and then Present (Packed_Array_Type (Parent (N)))
|
|
and then Present (First_Rep_Item (Parent (N)))
|
|
then
|
|
Error_Msg_N
|
|
("length of packed array must not exceed Integer''Last",
|
|
First_Rep_Item (Parent (N)));
|
|
Rewrite (N, Make_Integer_Literal (Sloc (N), Uint_1));
|
|
|
|
else
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "value not in range of}", CE_Range_Check_Failed);
|
|
end if;
|
|
|
|
-- Here we generate a warning for the Ada 83 case, or when we are
|
|
-- in an instance, or when we have a non-static expression case.
|
|
|
|
else
|
|
Apply_Compile_Time_Constraint_Error
|
|
(N, "value not in range of}?", CE_Range_Check_Failed);
|
|
end if;
|
|
end Out_Of_Range;
|
|
|
|
-------------------------
|
|
-- Rewrite_In_Raise_CE --
|
|
-------------------------
|
|
|
|
procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id) is
|
|
Typ : constant Entity_Id := Etype (N);
|
|
|
|
begin
|
|
-- If we want to raise CE in the condition of a raise_CE node
|
|
-- we may as well get rid of the condition
|
|
|
|
if Present (Parent (N))
|
|
and then Nkind (Parent (N)) = N_Raise_Constraint_Error
|
|
then
|
|
Set_Condition (Parent (N), Empty);
|
|
|
|
-- If the expression raising CE is a N_Raise_CE node, we can use
|
|
-- that one. We just preserve the type of the context
|
|
|
|
elsif Nkind (Exp) = N_Raise_Constraint_Error then
|
|
Rewrite (N, Exp);
|
|
Set_Etype (N, Typ);
|
|
|
|
-- We have to build an explicit raise_ce node
|
|
|
|
else
|
|
Rewrite (N,
|
|
Make_Raise_Constraint_Error (Sloc (Exp),
|
|
Reason => CE_Range_Check_Failed));
|
|
Set_Raises_Constraint_Error (N);
|
|
Set_Etype (N, Typ);
|
|
end if;
|
|
end Rewrite_In_Raise_CE;
|
|
|
|
---------------------
|
|
-- String_Type_Len --
|
|
---------------------
|
|
|
|
function String_Type_Len (Stype : Entity_Id) return Uint is
|
|
NT : constant Entity_Id := Etype (First_Index (Stype));
|
|
T : Entity_Id;
|
|
|
|
begin
|
|
if Is_OK_Static_Subtype (NT) then
|
|
T := NT;
|
|
else
|
|
T := Base_Type (NT);
|
|
end if;
|
|
|
|
return Expr_Value (Type_High_Bound (T)) -
|
|
Expr_Value (Type_Low_Bound (T)) + 1;
|
|
end String_Type_Len;
|
|
|
|
------------------------------------
|
|
-- Subtypes_Statically_Compatible --
|
|
------------------------------------
|
|
|
|
function Subtypes_Statically_Compatible
|
|
(T1 : Entity_Id;
|
|
T2 : Entity_Id)
|
|
return Boolean
|
|
is
|
|
begin
|
|
if Is_Scalar_Type (T1) then
|
|
|
|
-- Definitely compatible if we match
|
|
|
|
if Subtypes_Statically_Match (T1, T2) then
|
|
return True;
|
|
|
|
-- If either subtype is nonstatic then they're not compatible
|
|
|
|
elsif not Is_Static_Subtype (T1)
|
|
or else not Is_Static_Subtype (T2)
|
|
then
|
|
return False;
|
|
|
|
-- If either type has constraint error bounds, then consider that
|
|
-- they match to avoid junk cascaded errors here.
|
|
|
|
elsif not Is_OK_Static_Subtype (T1)
|
|
or else not Is_OK_Static_Subtype (T2)
|
|
then
|
|
return True;
|
|
|
|
-- Base types must match, but we don't check that (should
|
|
-- we???) but we do at least check that both types are
|
|
-- real, or both types are not real.
|
|
|
|
elsif Is_Real_Type (T1) /= Is_Real_Type (T2) then
|
|
return False;
|
|
|
|
-- Here we check the bounds
|
|
|
|
else
|
|
declare
|
|
LB1 : constant Node_Id := Type_Low_Bound (T1);
|
|
HB1 : constant Node_Id := Type_High_Bound (T1);
|
|
LB2 : constant Node_Id := Type_Low_Bound (T2);
|
|
HB2 : constant Node_Id := Type_High_Bound (T2);
|
|
|
|
begin
|
|
if Is_Real_Type (T1) then
|
|
return
|
|
(Expr_Value_R (LB1) > Expr_Value_R (HB1))
|
|
or else
|
|
(Expr_Value_R (LB2) <= Expr_Value_R (LB1)
|
|
and then
|
|
Expr_Value_R (HB1) <= Expr_Value_R (HB2));
|
|
|
|
else
|
|
return
|
|
(Expr_Value (LB1) > Expr_Value (HB1))
|
|
or else
|
|
(Expr_Value (LB2) <= Expr_Value (LB1)
|
|
and then
|
|
Expr_Value (HB1) <= Expr_Value (HB2));
|
|
end if;
|
|
end;
|
|
end if;
|
|
|
|
elsif Is_Access_Type (T1) then
|
|
return not Is_Constrained (T2)
|
|
or else Subtypes_Statically_Match
|
|
(Designated_Type (T1), Designated_Type (T2));
|
|
|
|
else
|
|
return (Is_Composite_Type (T1) and then not Is_Constrained (T2))
|
|
or else Subtypes_Statically_Match (T1, T2);
|
|
end if;
|
|
end Subtypes_Statically_Compatible;
|
|
|
|
-------------------------------
|
|
-- Subtypes_Statically_Match --
|
|
-------------------------------
|
|
|
|
-- Subtypes statically match if they have statically matching constraints
|
|
-- (RM 4.9.1(2)). Constraints statically match if there are none, or if
|
|
-- they are the same identical constraint, or if they are static and the
|
|
-- values match (RM 4.9.1(1)).
|
|
|
|
function Subtypes_Statically_Match (T1, T2 : Entity_Id) return Boolean is
|
|
begin
|
|
-- A type always statically matches itself
|
|
|
|
if T1 = T2 then
|
|
return True;
|
|
|
|
-- Scalar types
|
|
|
|
elsif Is_Scalar_Type (T1) then
|
|
|
|
-- Base types must be the same
|
|
|
|
if Base_Type (T1) /= Base_Type (T2) then
|
|
return False;
|
|
end if;
|
|
|
|
-- A constrained numeric subtype never matches an unconstrained
|
|
-- subtype, i.e. both types must be constrained or unconstrained.
|
|
|
|
-- To understand the requirement for this test, see RM 4.9.1(1).
|
|
-- As is made clear in RM 3.5.4(11), type Integer, for example
|
|
-- is a constrained subtype with constraint bounds matching the
|
|
-- bounds of its corresponding uncontrained base type. In this
|
|
-- situation, Integer and Integer'Base do not statically match,
|
|
-- even though they have the same bounds.
|
|
|
|
-- We only apply this test to types in Standard and types that
|
|
-- appear in user programs. That way, we do not have to be
|
|
-- too careful about setting Is_Constrained right for itypes.
|
|
|
|
if Is_Numeric_Type (T1)
|
|
and then (Is_Constrained (T1) /= Is_Constrained (T2))
|
|
and then (Scope (T1) = Standard_Standard
|
|
or else Comes_From_Source (T1))
|
|
and then (Scope (T2) = Standard_Standard
|
|
or else Comes_From_Source (T2))
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
-- If there was an error in either range, then just assume
|
|
-- the types statically match to avoid further junk errors
|
|
|
|
if Error_Posted (Scalar_Range (T1))
|
|
or else
|
|
Error_Posted (Scalar_Range (T2))
|
|
then
|
|
return True;
|
|
end if;
|
|
|
|
-- Otherwise both types have bound that can be compared
|
|
|
|
declare
|
|
LB1 : constant Node_Id := Type_Low_Bound (T1);
|
|
HB1 : constant Node_Id := Type_High_Bound (T1);
|
|
LB2 : constant Node_Id := Type_Low_Bound (T2);
|
|
HB2 : constant Node_Id := Type_High_Bound (T2);
|
|
|
|
begin
|
|
-- If the bounds are the same tree node, then match
|
|
|
|
if LB1 = LB2 and then HB1 = HB2 then
|
|
return True;
|
|
|
|
-- Otherwise bounds must be static and identical value
|
|
|
|
else
|
|
if not Is_Static_Subtype (T1)
|
|
or else not Is_Static_Subtype (T2)
|
|
then
|
|
return False;
|
|
|
|
-- If either type has constraint error bounds, then say
|
|
-- that they match to avoid junk cascaded errors here.
|
|
|
|
elsif not Is_OK_Static_Subtype (T1)
|
|
or else not Is_OK_Static_Subtype (T2)
|
|
then
|
|
return True;
|
|
|
|
elsif Is_Real_Type (T1) then
|
|
return
|
|
(Expr_Value_R (LB1) = Expr_Value_R (LB2))
|
|
and then
|
|
(Expr_Value_R (HB1) = Expr_Value_R (HB2));
|
|
|
|
else
|
|
return
|
|
Expr_Value (LB1) = Expr_Value (LB2)
|
|
and then
|
|
Expr_Value (HB1) = Expr_Value (HB2);
|
|
end if;
|
|
end if;
|
|
end;
|
|
|
|
-- Type with discriminants
|
|
|
|
elsif Has_Discriminants (T1) or else Has_Discriminants (T2) then
|
|
if Has_Discriminants (T1) /= Has_Discriminants (T2) then
|
|
return False;
|
|
end if;
|
|
|
|
declare
|
|
DL1 : constant Elist_Id := Discriminant_Constraint (T1);
|
|
DL2 : constant Elist_Id := Discriminant_Constraint (T2);
|
|
|
|
DA1 : Elmt_Id := First_Elmt (DL1);
|
|
DA2 : Elmt_Id := First_Elmt (DL2);
|
|
|
|
begin
|
|
if DL1 = DL2 then
|
|
return True;
|
|
|
|
elsif Is_Constrained (T1) /= Is_Constrained (T2) then
|
|
return False;
|
|
end if;
|
|
|
|
while Present (DA1) loop
|
|
declare
|
|
Expr1 : constant Node_Id := Node (DA1);
|
|
Expr2 : constant Node_Id := Node (DA2);
|
|
|
|
begin
|
|
if not Is_Static_Expression (Expr1)
|
|
or else not Is_Static_Expression (Expr2)
|
|
then
|
|
return False;
|
|
|
|
-- If either expression raised a constraint error,
|
|
-- consider the expressions as matching, since this
|
|
-- helps to prevent cascading errors.
|
|
|
|
elsif Raises_Constraint_Error (Expr1)
|
|
or else Raises_Constraint_Error (Expr2)
|
|
then
|
|
null;
|
|
|
|
elsif Expr_Value (Expr1) /= Expr_Value (Expr2) then
|
|
return False;
|
|
end if;
|
|
end;
|
|
|
|
Next_Elmt (DA1);
|
|
Next_Elmt (DA2);
|
|
end loop;
|
|
end;
|
|
|
|
return True;
|
|
|
|
-- A definite type does not match an indefinite or classwide type.
|
|
|
|
elsif
|
|
Has_Unknown_Discriminants (T1) /= Has_Unknown_Discriminants (T2)
|
|
then
|
|
return False;
|
|
|
|
-- Array type
|
|
|
|
elsif Is_Array_Type (T1) then
|
|
|
|
-- If either subtype is unconstrained then both must be,
|
|
-- and if both are unconstrained then no further checking
|
|
-- is needed.
|
|
|
|
if not Is_Constrained (T1) or else not Is_Constrained (T2) then
|
|
return not (Is_Constrained (T1) or else Is_Constrained (T2));
|
|
end if;
|
|
|
|
-- Both subtypes are constrained, so check that the index
|
|
-- subtypes statically match.
|
|
|
|
declare
|
|
Index1 : Node_Id := First_Index (T1);
|
|
Index2 : Node_Id := First_Index (T2);
|
|
|
|
begin
|
|
while Present (Index1) loop
|
|
if not
|
|
Subtypes_Statically_Match (Etype (Index1), Etype (Index2))
|
|
then
|
|
return False;
|
|
end if;
|
|
|
|
Next_Index (Index1);
|
|
Next_Index (Index2);
|
|
end loop;
|
|
|
|
return True;
|
|
end;
|
|
|
|
elsif Is_Access_Type (T1) then
|
|
return Subtypes_Statically_Match
|
|
(Designated_Type (T1),
|
|
Designated_Type (T2));
|
|
|
|
-- All other types definitely match
|
|
|
|
else
|
|
return True;
|
|
end if;
|
|
end Subtypes_Statically_Match;
|
|
|
|
----------
|
|
-- Test --
|
|
----------
|
|
|
|
function Test (Cond : Boolean) return Uint is
|
|
begin
|
|
if Cond then
|
|
return Uint_1;
|
|
else
|
|
return Uint_0;
|
|
end if;
|
|
end Test;
|
|
|
|
---------------------------------
|
|
-- Test_Expression_Is_Foldable --
|
|
---------------------------------
|
|
|
|
-- One operand case
|
|
|
|
procedure Test_Expression_Is_Foldable
|
|
(N : Node_Id;
|
|
Op1 : Node_Id;
|
|
Stat : out Boolean;
|
|
Fold : out Boolean)
|
|
is
|
|
begin
|
|
Stat := False;
|
|
|
|
-- If operand is Any_Type, just propagate to result and do not
|
|
-- try to fold, this prevents cascaded errors.
|
|
|
|
if Etype (Op1) = Any_Type then
|
|
Set_Etype (N, Any_Type);
|
|
Fold := False;
|
|
return;
|
|
|
|
-- If operand raises constraint error, then replace node N with the
|
|
-- raise constraint error node, and we are obviously not foldable.
|
|
-- Note that this replacement inherits the Is_Static_Expression flag
|
|
-- from the operand.
|
|
|
|
elsif Raises_Constraint_Error (Op1) then
|
|
Rewrite_In_Raise_CE (N, Op1);
|
|
Fold := False;
|
|
return;
|
|
|
|
-- If the operand is not static, then the result is not static, and
|
|
-- all we have to do is to check the operand since it is now known
|
|
-- to appear in a non-static context.
|
|
|
|
elsif not Is_Static_Expression (Op1) then
|
|
Check_Non_Static_Context (Op1);
|
|
Fold := Compile_Time_Known_Value (Op1);
|
|
return;
|
|
|
|
-- An expression of a formal modular type is not foldable because
|
|
-- the modulus is unknown.
|
|
|
|
elsif Is_Modular_Integer_Type (Etype (Op1))
|
|
and then Is_Generic_Type (Etype (Op1))
|
|
then
|
|
Check_Non_Static_Context (Op1);
|
|
Fold := False;
|
|
return;
|
|
|
|
-- Here we have the case of an operand whose type is OK, which is
|
|
-- static, and which does not raise constraint error, we can fold.
|
|
|
|
else
|
|
Set_Is_Static_Expression (N);
|
|
Fold := True;
|
|
Stat := True;
|
|
end if;
|
|
end Test_Expression_Is_Foldable;
|
|
|
|
-- Two operand case
|
|
|
|
procedure Test_Expression_Is_Foldable
|
|
(N : Node_Id;
|
|
Op1 : Node_Id;
|
|
Op2 : Node_Id;
|
|
Stat : out Boolean;
|
|
Fold : out Boolean)
|
|
is
|
|
Rstat : constant Boolean := Is_Static_Expression (Op1)
|
|
and then Is_Static_Expression (Op2);
|
|
|
|
begin
|
|
Stat := False;
|
|
|
|
-- If either operand is Any_Type, just propagate to result and
|
|
-- do not try to fold, this prevents cascaded errors.
|
|
|
|
if Etype (Op1) = Any_Type or else Etype (Op2) = Any_Type then
|
|
Set_Etype (N, Any_Type);
|
|
Fold := False;
|
|
return;
|
|
|
|
-- If left operand raises constraint error, then replace node N with
|
|
-- the raise constraint error node, and we are obviously not foldable.
|
|
-- Is_Static_Expression is set from the two operands in the normal way,
|
|
-- and we check the right operand if it is in a non-static context.
|
|
|
|
elsif Raises_Constraint_Error (Op1) then
|
|
if not Rstat then
|
|
Check_Non_Static_Context (Op2);
|
|
end if;
|
|
|
|
Rewrite_In_Raise_CE (N, Op1);
|
|
Set_Is_Static_Expression (N, Rstat);
|
|
Fold := False;
|
|
return;
|
|
|
|
-- Similar processing for the case of the right operand. Note that
|
|
-- we don't use this routine for the short-circuit case, so we do
|
|
-- not have to worry about that special case here.
|
|
|
|
elsif Raises_Constraint_Error (Op2) then
|
|
if not Rstat then
|
|
Check_Non_Static_Context (Op1);
|
|
end if;
|
|
|
|
Rewrite_In_Raise_CE (N, Op2);
|
|
Set_Is_Static_Expression (N, Rstat);
|
|
Fold := False;
|
|
return;
|
|
|
|
-- Exclude expressions of a generic modular type, as above.
|
|
|
|
elsif Is_Modular_Integer_Type (Etype (Op1))
|
|
and then Is_Generic_Type (Etype (Op1))
|
|
then
|
|
Check_Non_Static_Context (Op1);
|
|
Fold := False;
|
|
return;
|
|
|
|
-- If result is not static, then check non-static contexts on operands
|
|
-- since one of them may be static and the other one may not be static
|
|
|
|
elsif not Rstat then
|
|
Check_Non_Static_Context (Op1);
|
|
Check_Non_Static_Context (Op2);
|
|
Fold := Compile_Time_Known_Value (Op1)
|
|
and then Compile_Time_Known_Value (Op2);
|
|
return;
|
|
|
|
-- Else result is static and foldable. Both operands are static,
|
|
-- and neither raises constraint error, so we can definitely fold.
|
|
|
|
else
|
|
Set_Is_Static_Expression (N);
|
|
Fold := True;
|
|
Stat := True;
|
|
return;
|
|
end if;
|
|
end Test_Expression_Is_Foldable;
|
|
|
|
--------------
|
|
-- To_Bits --
|
|
--------------
|
|
|
|
procedure To_Bits (U : Uint; B : out Bits) is
|
|
begin
|
|
for J in 0 .. B'Last loop
|
|
B (J) := (U / (2 ** J)) mod 2 /= 0;
|
|
end loop;
|
|
end To_Bits;
|
|
|
|
--------------------
|
|
-- Why_Not_Static --
|
|
--------------------
|
|
|
|
procedure Why_Not_Static (Expr : Node_Id) is
|
|
N : constant Node_Id := Original_Node (Expr);
|
|
Typ : Entity_Id;
|
|
E : Entity_Id;
|
|
|
|
procedure Why_Not_Static_List (L : List_Id);
|
|
-- A version that can be called on a list of expressions. Finds
|
|
-- all non-static violations in any element of the list.
|
|
|
|
-------------------------
|
|
-- Why_Not_Static_List --
|
|
-------------------------
|
|
|
|
procedure Why_Not_Static_List (L : List_Id) is
|
|
N : Node_Id;
|
|
|
|
begin
|
|
if Is_Non_Empty_List (L) then
|
|
N := First (L);
|
|
while Present (N) loop
|
|
Why_Not_Static (N);
|
|
Next (N);
|
|
end loop;
|
|
end if;
|
|
end Why_Not_Static_List;
|
|
|
|
-- Start of processing for Why_Not_Static
|
|
|
|
begin
|
|
-- If in ACATS mode (debug flag 2), then suppress all these
|
|
-- messages, this avoids massive updates to the ACATS base line.
|
|
|
|
if Debug_Flag_2 then
|
|
return;
|
|
end if;
|
|
|
|
-- Ignore call on error or empty node
|
|
|
|
if No (Expr) or else Nkind (Expr) = N_Error then
|
|
return;
|
|
end if;
|
|
|
|
-- Preprocessing for sub expressions
|
|
|
|
if Nkind (Expr) in N_Subexpr then
|
|
|
|
-- Nothing to do if expression is static
|
|
|
|
if Is_OK_Static_Expression (Expr) then
|
|
return;
|
|
end if;
|
|
|
|
-- Test for constraint error raised
|
|
|
|
if Raises_Constraint_Error (Expr) then
|
|
Error_Msg_N
|
|
("expression raises exception, cannot be static " &
|
|
"('R'M 4.9(34))!", N);
|
|
return;
|
|
end if;
|
|
|
|
-- If no type, then something is pretty wrong, so ignore
|
|
|
|
Typ := Etype (Expr);
|
|
|
|
if No (Typ) then
|
|
return;
|
|
end if;
|
|
|
|
-- Type must be scalar or string type
|
|
|
|
if not Is_Scalar_Type (Typ)
|
|
and then not Is_String_Type (Typ)
|
|
then
|
|
Error_Msg_N
|
|
("static expression must have scalar or string type " &
|
|
"('R'M 4.9(2))!", N);
|
|
return;
|
|
end if;
|
|
end if;
|
|
|
|
-- If we got through those checks, test particular node kind
|
|
|
|
case Nkind (N) is
|
|
when N_Expanded_Name | N_Identifier | N_Operator_Symbol =>
|
|
E := Entity (N);
|
|
|
|
if Is_Named_Number (E) then
|
|
null;
|
|
|
|
elsif Ekind (E) = E_Constant then
|
|
if not Is_Static_Expression (Constant_Value (E)) then
|
|
Error_Msg_NE
|
|
("& is not a static constant ('R'M 4.9(5))!", N, E);
|
|
end if;
|
|
|
|
else
|
|
Error_Msg_NE
|
|
("& is not static constant or named number " &
|
|
"('R'M 4.9(5))!", N, E);
|
|
end if;
|
|
|
|
when N_Binary_Op | N_And_Then | N_Or_Else | N_In | N_Not_In =>
|
|
if Nkind (N) in N_Op_Shift then
|
|
Error_Msg_N
|
|
("shift functions are never static ('R'M 4.9(6,18))!", N);
|
|
|
|
else
|
|
Why_Not_Static (Left_Opnd (N));
|
|
Why_Not_Static (Right_Opnd (N));
|
|
end if;
|
|
|
|
when N_Unary_Op =>
|
|
Why_Not_Static (Right_Opnd (N));
|
|
|
|
when N_Attribute_Reference =>
|
|
Why_Not_Static_List (Expressions (N));
|
|
|
|
E := Etype (Prefix (N));
|
|
|
|
if E = Standard_Void_Type then
|
|
return;
|
|
end if;
|
|
|
|
-- Special case non-scalar'Size since this is a common error
|
|
|
|
if Attribute_Name (N) = Name_Size then
|
|
Error_Msg_N
|
|
("size attribute is only static for scalar type " &
|
|
"('R'M 4.9(7,8))", N);
|
|
|
|
-- Flag array cases
|
|
|
|
elsif Is_Array_Type (E) then
|
|
if Attribute_Name (N) /= Name_First
|
|
and then
|
|
Attribute_Name (N) /= Name_Last
|
|
and then
|
|
Attribute_Name (N) /= Name_Length
|
|
then
|
|
Error_Msg_N
|
|
("static array attribute must be Length, First, or Last " &
|
|
"('R'M 4.9(8))!", N);
|
|
|
|
-- Since we know the expression is not-static (we already
|
|
-- tested for this, must mean array is not static).
|
|
|
|
else
|
|
Error_Msg_N
|
|
("prefix is non-static array ('R'M 4.9(8))!", Prefix (N));
|
|
end if;
|
|
|
|
return;
|
|
|
|
-- Special case generic types, since again this is a common
|
|
-- source of confusion.
|
|
|
|
elsif Is_Generic_Actual_Type (E)
|
|
or else
|
|
Is_Generic_Type (E)
|
|
then
|
|
Error_Msg_N
|
|
("attribute of generic type is never static " &
|
|
"('R'M 4.9(7,8))!", N);
|
|
|
|
elsif Is_Static_Subtype (E) then
|
|
null;
|
|
|
|
elsif Is_Scalar_Type (E) then
|
|
Error_Msg_N
|
|
("prefix type for attribute is not static scalar subtype " &
|
|
"('R'M 4.9(7))!", N);
|
|
|
|
else
|
|
Error_Msg_N
|
|
("static attribute must apply to array/scalar type " &
|
|
"('R'M 4.9(7,8))!", N);
|
|
end if;
|
|
|
|
when N_String_Literal =>
|
|
Error_Msg_N
|
|
("subtype of string literal is non-static ('R'M 4.9(4))!", N);
|
|
|
|
when N_Explicit_Dereference =>
|
|
Error_Msg_N
|
|
("explicit dereference is never static ('R'M 4.9)!", N);
|
|
|
|
when N_Function_Call =>
|
|
Why_Not_Static_List (Parameter_Associations (N));
|
|
Error_Msg_N ("non-static function call ('R'M 4.9(6,18))!", N);
|
|
|
|
when N_Parameter_Association =>
|
|
Why_Not_Static (Explicit_Actual_Parameter (N));
|
|
|
|
when N_Indexed_Component =>
|
|
Error_Msg_N
|
|
("indexed component is never static ('R'M 4.9)!", N);
|
|
|
|
when N_Procedure_Call_Statement =>
|
|
Error_Msg_N
|
|
("procedure call is never static ('R'M 4.9)!", N);
|
|
|
|
when N_Qualified_Expression =>
|
|
Why_Not_Static (Expression (N));
|
|
|
|
when N_Aggregate | N_Extension_Aggregate =>
|
|
Error_Msg_N
|
|
("an aggregate is never static ('R'M 4.9)!", N);
|
|
|
|
when N_Range =>
|
|
Why_Not_Static (Low_Bound (N));
|
|
Why_Not_Static (High_Bound (N));
|
|
|
|
when N_Range_Constraint =>
|
|
Why_Not_Static (Range_Expression (N));
|
|
|
|
when N_Subtype_Indication =>
|
|
Why_Not_Static (Constraint (N));
|
|
|
|
when N_Selected_Component =>
|
|
Error_Msg_N
|
|
("selected component is never static ('R'M 4.9)!", N);
|
|
|
|
when N_Slice =>
|
|
Error_Msg_N
|
|
("slice is never static ('R'M 4.9)!", N);
|
|
|
|
when N_Type_Conversion =>
|
|
Why_Not_Static (Expression (N));
|
|
|
|
if not Is_Scalar_Type (Etype (Prefix (N)))
|
|
or else not Is_Static_Subtype (Etype (Prefix (N)))
|
|
then
|
|
Error_Msg_N
|
|
("static conversion requires static scalar subtype result " &
|
|
"('R'M 4.9(9))!", N);
|
|
end if;
|
|
|
|
when N_Unchecked_Type_Conversion =>
|
|
Error_Msg_N
|
|
("unchecked type conversion is never static ('R'M 4.9)!", N);
|
|
|
|
when others =>
|
|
null;
|
|
|
|
end case;
|
|
end Why_Not_Static;
|
|
|
|
end Sem_Eval;
|