695 lines
30 KiB
Ada
695 lines
30 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- E X P _ U N S T --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 2014-2016, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING3. If not, go to --
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-- http://www.gnu.org/licenses for a complete copy of the license. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- Expand routines for unnesting subprograms
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with Table;
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with Types; use Types;
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package Exp_Unst is
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-- -----------------
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-- -- The Problem --
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-- -----------------
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-- Normally, nested subprograms in the source result in corresponding
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-- nested subprograms in the resulting tree. We then expect the back end
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-- to handle such nested subprograms, including all cases of uplevel
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-- references. For example, the GCC back end can do this relatively easily
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-- since GNU C (as an extension) allows nested functions with uplevel
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-- references, and implements an appropriate static chain approach to
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-- dealing with such uplevel references.
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-- However, we also want to be able to interface with back ends that do
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-- not easily handle such uplevel references. One example is the back end
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-- that translates the tree into standard C source code. In the future,
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-- other back ends might need the same capability (e.g. a back end that
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-- generated LLVM intermediate code).
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-- We could imagine simply handling such references in the appropriate
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-- back end. For example the back end that generates C could recognize
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-- nested subprograms and rig up some way of translating them, e.g. by
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-- making a static-link source level visible.
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-- Rather than take that approach, we prefer to do a semantics-preserving
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-- transformation on the GNAT tree, that eliminates the problem before we
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-- hand the tree over to the back end. There are two reasons for preferring
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-- this approach:
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-- First: the work needs only to be done once for all affected back ends
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-- and we can remain within the semantics of the tree. The front end is
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-- full of tree transformations, so we have all the infrastructure for
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-- doing transformations of this type.
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-- Second: given that the transformation will be semantics-preserving,
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-- we can still used the standard GCC back end to build code from it.
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-- This means we can easily run our full test suite to verify that the
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-- transformations are indeed semantics preserving. It is a lot more
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-- work to thoroughly test the output of specialized back ends.
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-- Looking at the problem, we have three situations to deal with. Note
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-- that in these examples, we use all lower case, since that is the way
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-- the internal tree is cased.
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-- First, cases where there are no uplevel references, for example
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-- procedure case1 is
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-- function max (m, n : Integer) return integer is
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-- begin
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-- return integer'max (m, n);
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-- end max;
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-- ...
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-- end case1;
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-- Second, cases where there are explicit uplevel references.
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-- procedure case2 (b : integer) is
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-- procedure Inner (bb : integer);
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--
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-- procedure inner2 is
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-- begin
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-- inner(5);
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-- end;
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--
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-- x : integer := 77;
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-- y : constant integer := 15 * 16;
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-- rv : integer := 10;
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--
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-- procedure inner (bb : integer) is
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-- begin
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-- x := rv + y + bb + b;
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-- end;
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--
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-- begin
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-- inner2;
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-- end case2;
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-- In this second example, B, X, RV are uplevel referenced. Y is not
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-- considered as an uplevel reference since it is a static constant
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-- where references are replaced by the value at compile time.
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-- Third, cases where there are implicit uplevel references via types
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-- whose bounds depend on locally declared constants or variables:
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-- function case3 (x, y : integer) return boolean is
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-- subtype dynam is integer range x .. y + 3;
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-- subtype static is integer range 42 .. 73;
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-- xx : dynam := y;
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--
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-- type darr is array (dynam) of Integer;
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-- type darec is record
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-- A : darr;
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-- B : integer;
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-- end record;
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-- darecv : darec;
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--
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-- function inner (b : integer) return boolean is
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-- begin
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-- return b in dynam and then darecv.b in static;
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-- end inner;
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--
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-- begin
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-- return inner (42) and then inner (xx * 3 - y * 2);
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-- end case3;
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--
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-- In this third example, the membership test implicitly references the
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-- the bounds of Dynam, which both involve uplevel references.
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-- ------------------
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-- -- The Solution --
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-- ------------------
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-- Looking at the three cases above, the first case poses no problem at
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-- all. Indeed the subprogram could have been declared at the outer level
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-- (perhaps changing the name). But this style is quite common as a way
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-- of limiting the scope of a local procedure called only within the outer
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-- procedure. We could move it to the outer level (with a name change if
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-- needed), but we don't bother. We leave it nested, and the back end just
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-- translates it as though it were not nested.
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-- In general we leave nested procedures nested, rather than trying to move
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-- them to the outer level (the back end may do that, e.g. as part of the
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-- translation to C, but we don't do it in the tree itself). This saves a
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-- LOT of trouble in terms of visibility and semantics.
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-- But of course we have to deal with the uplevel references. The idea is
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-- to rewrite these nested subprograms so that they no longer have any such
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-- uplevel references, so by the time they reach the back end, they all are
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-- case 1 (no uplevel references) and thus easily handled.
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-- To deal with explicit uplevel references (case 2 above), we proceed with
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-- the following steps:
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-- All entities marked as being uplevel referenced are marked as aliased
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-- since they will be accessed indirectly via an activation record as
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-- described below.
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-- An activation record is created containing system address values
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-- for each uplevel referenced entity in a given scope. In the example
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-- given before, we would have:
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-- type AREC1T is record
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-- b : Address;
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-- x : Address;
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-- rv : Address;
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-- end record;
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-- type AREC1PT is access all AREC1T;
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-- AREC1 : aliased AREC1T;
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-- AREC1P : constant AREC1PT := AREC1'Access;
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-- The fields of AREC1 are set at the point the corresponding entity
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-- is declared (immediately for parameters).
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-- Note: the 1 in all these names is a unique index number. Different
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-- scopes requiring different ARECnT declarations will have different
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-- values of n to ensure uniqueness.
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-- Note: normally the field names in the activation record match the
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-- name of the entity. An exception is when the entity is declared in
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-- a declare block, in which case we append the entity number, to avoid
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-- clashes between the same name declared in different declare blocks.
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-- For all subprograms nested immediately within the corresponding scope,
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-- a parameter AREC1F is passed, and all calls to these routines have
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-- AREC1P added as an additional formal.
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-- Now within the nested procedures, any reference to an uplevel entity
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-- xxx is replaced by typ'Deref(AREC1.xxx) where typ is the type of the
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-- reference.
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-- Note: the reason that we use Address as the component type in the
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-- declaration of AREC1T is that we may create this type before we see
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-- the declaration of this type.
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-- The following shows example 2 above after this translation:
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-- procedure case2x (b : aliased Integer) is
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-- type AREC1T is record
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-- b : Address;
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-- x : Address;
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-- rv : Address;
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-- end record;
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--
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-- type AREC1PT is access all AREC1T;
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--
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-- AREC1 : aliased AREC1T;
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-- AREC1P : constant AREC1PT := AREC1'Access;
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--
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-- AREC1.b := b'Address;
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--
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-- procedure inner (bb : integer; AREC1F : AREC1PT);
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--
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-- procedure inner2 (AREC1F : AREC1PT) is
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-- begin
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-- inner(5, AREC1F);
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-- end;
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--
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-- x : aliased integer := 77;
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-- AREC1.x := X'Address;
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--
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-- y : constant Integer := 15 * 16;
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--
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-- rv : aliased Integer;
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-- AREC1.rv := rv'Address;
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--
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-- procedure inner (bb : integer; AREC1F : AREC1PT) is
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-- begin
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-- Integer'Deref(AREC1F.x) :=
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-- Integer'Deref(AREC1F.rv) + y + b + Integer_Deref(AREC1F.b);
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-- end;
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--
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-- begin
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-- inner2 (AREC1P);
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-- end case2x;
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-- And now the inner procedures INNER2 and INNER have no uplevel references
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-- so they have been reduced to case 1, which is the case easily handled by
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-- the back end. Note that the generated code is not strictly legal Ada
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-- because of the assignments to AREC1 in the declarative sequence, but the
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-- GNAT tree always allows such mixing of declarations and statements, so
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-- the back end must be prepared to handle this in any case.
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-- Case 3 where we have uplevel references to types is a bit more complex.
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-- That would especially be the case if we did a full transformation that
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-- completely eliminated such uplevel references as we did for case 2. But
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-- instead of trying to do that, we rewrite the subprogram so that the code
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-- generator can easily detect and deal with these uplevel type references.
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-- First we distinguish two cases
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-- Static types are one of the two following cases:
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-- Discrete types whose bounds are known at compile time. This is not
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-- quite the same as what is tested by Is_OK_Static_Subtype, in that
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-- it allows compile time known values that are not static expressions.
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-- Composite types, whose components are (recursively) static types.
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-- Dynamic types are one of the two following cases:
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-- Discrete types with at least one bound not known at compile time.
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-- Composite types with at least one component that is (recursively)
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-- a dynamic type.
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-- Uplevel references to static types are not a problem, the front end
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-- or the code generator fetches the bounds as required, and since they
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-- are compile time known values, this value can just be extracted and
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-- no actual uplevel reference is required.
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-- Uplevel references to dynamic types are a potential problem, since
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-- such references may involve an implicit access to a dynamic bound,
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-- and this reference is an implicit uplevel access.
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-- To fully unnest such references would be messy, since we would have
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-- to create local copies of the dynamic types involved, so that the
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-- front end or code generator could generate an explicit uplevel
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-- reference to the bound involved. Rather than do that, we set things
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-- up so that this situation can be easily detected and dealt with when
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-- there is an implicit reference to the bounds.
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-- What we do is to always generate a local constant for any dynamic
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-- bound in a dynamic subtype xx with name xx_FIRST or xx_LAST. The one
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-- case where we can skip this is where the bound is e.g. in the third
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-- example above, subtype dynam is expanded as
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-- dynam_LAST : constant Integer := y + 3;
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-- subtype dynam is integer range x .. dynam_LAST;
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-- Now if type dynam is uplevel referenced (as it is this case), then
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-- the bounds x and dynam_LAST are marked as uplevel references
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-- so that appropriate entries are made in the activation record. Any
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-- explicit reference to such a bound in the front end generated code
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-- will be handled by the normal uplevel reference mechanism which we
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-- described above for case 2. For implicit references by a back end
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-- that needs to unnest things, any such implicit reference to one of
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-- these bounds can be replaced by an appropriate reference to the entry
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-- in the activation record for xx_FIRST or xx_LAST. Thus the back end
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-- can eliminate the problematical uplevel reference without the need to
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-- do the heavy tree modification to do that at the code expansion level
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-- Looking at case 3 again, here is the normal -gnatG expanded code
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-- function case3 (x : integer; y : integer) return boolean is
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-- dynam_LAST : constant integer := y {+} 3;
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-- subtype dynam is integer range x .. dynam_LAST;
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-- subtype static is integer range 42 .. 73;
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--
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-- [constraint_error when
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-- not (y in x .. dynam_LAST)
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-- "range check failed"]
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--
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-- xx : dynam := y;
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--
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-- type darr is array (x .. dynam_LAST) of integer;
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-- type darec is record
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-- a : darr;
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-- b : integer;
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-- end record;
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-- [type TdarrB is array (x .. dynam_LAST range <>) of integer]
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-- freeze TdarrB []
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-- darecv : darec;
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--
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-- function inner (b : integer) return boolean is
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-- begin
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-- return b in x .. dynam_LAST and then darecv.b in 42 .. 73;
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-- end inner;
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-- begin
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-- return inner (42) and then inner (xx {*} 3 {-} y {*} 2);
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-- end case3;
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-- Note: the actual expanded code has fully qualified names so for
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-- example function inner is actually function case3__inner. For now
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-- we ignore that detail to clarify the examples.
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-- Here we see that some of the bounds references are expanded by the
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-- front end, so that we get explicit references to y or dynamLast. These
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-- cases are handled by the normal uplevel reference mechanism described
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-- above for case 2. This is the case for the constraint check for the
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-- initialization of xx, and the range check in function inner.
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-- But the reference darecv.b in the return statement of function
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-- inner has an implicit reference to the bounds of dynam, since to
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-- compute the location of b in the record, we need the length of a.
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-- Here is the full translation of the third example:
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-- function case3x (x, y : integer) return boolean is
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-- type AREC1T is record
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-- x : Address;
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-- dynam_LAST : Address;
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-- end record;
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--
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-- type AREC1PT is access all AREC1T;
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--
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-- AREC1 : aliased AREC1T;
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-- AREC1P : constant AREC1PT := AREC1'Access;
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--
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-- AREC1.x := x'Address;
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--
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-- dynam_LAST : constant integer := y {+} 3;
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-- AREC1.dynam_LAST := dynam_LAST'Address;
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-- subtype dynam is integer range x .. dynam_LAST;
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-- xx : dynam := y;
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--
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-- [constraint_error when
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-- not (y in x .. dynam_LAST)
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-- "range check failed"]
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--
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-- subtype static is integer range 42 .. 73;
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--
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-- type darr is array (x .. dynam_LAST) of Integer;
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-- type darec is record
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-- A : darr;
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-- B : integer;
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-- end record;
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-- darecv : darec;
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--
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-- function inner (b : integer; AREC1F : AREC1PT) return boolean is
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-- begin
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-- return b in x .. Integer'Deref(AREC1F.dynam_LAST)
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-- and then darecv.b in 42 .. 73;
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-- end inner;
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--
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-- begin
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-- return inner (42, AREC1P) and then inner (xx * 3, AREC1P);
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-- end case3x;
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-- And now the back end when it processes darecv.b will access the bounds
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-- of darecv.a by referencing the d and dynam_LAST fields of AREC1P.
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-----------------------------
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-- Multiple Nesting Levels --
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-----------------------------
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-- In our examples so far, we have only nested to a single level, but the
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-- scheme generalizes to multiple levels of nesting and in this section we
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-- discuss how this generalization works.
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-- Consider this example with two nesting levels
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-- To deal with elimination of uplevel references, we follow the same basic
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-- approach described above for case 2, except that we need an activation
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-- record at each nested level. Basically the rule is that any procedure
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-- that has nested procedures needs an activation record. When we do this,
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-- the inner activation records have a pointer (uplink) to the immediately
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-- enclosing activation record, the normal arrangement of static links. The
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-- following shows the full translation of this fourth case.
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-- function case4x (x : integer) return integer is
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-- type AREC1T is record
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-- v1 : Address;
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-- end record;
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--
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-- type AREC1PT is access all AREC1T;
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--
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-- AREC1 : aliased AREC1T;
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-- AREC1P : constant AREC1PT := AREC1'Access;
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--
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-- v1 : integer := x;
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-- AREC1.v1 := v1'Address;
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--
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-- function inner1 (y : integer; AREC1F : AREC1PT) return integer is
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-- type AREC2T is record
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-- AREC1U : AREC1PT;
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-- v2 : Address;
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-- end record;
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--
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-- type AREC2PT is access all AREC2T;
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--
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-- AREC2 : aliased AREC2T;
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-- AREC2P : constant AREC2PT := AREC2'Access;
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--
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-- AREC2.AREC1U := AREC1F;
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--
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-- v2 : integer := Integer'Deref (AREC1F.v1) {+} 1;
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-- AREC2.v2 := v2'Address;
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--
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-- function inner2
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-- (z : integer; AREC2F : AREC2PT) return integer
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-- is
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-- begin
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-- return integer(z {+}
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-- Integer'Deref (AREC2F.AREC1U.v1) {+}
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-- Integer'Deref (AREC2F.v2).all);
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-- end inner2;
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-- begin
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-- return integer(y {+}
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-- inner2 (Integer'Deref (AREC1F.v1), AREC2P));
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-- end inner1;
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-- begin
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-- return inner1 (x, AREC1P);
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-- end case4x;
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-- As can be seen in this example, the index numbers following AREC in the
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-- generated names avoid confusion between AREC names at different levels.
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-------------------------
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-- Name Disambiguation --
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-------------------------
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-- As described above, the translation scheme would raise issues when the
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-- code generator did the actual unnesting if identically named nested
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-- subprograms exist. Similarly overloading would cause a naming issue.
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-- In fact, the expanded code includes qualified names which eliminate this
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-- problem. We omitted the qualification from the exapnded examples above
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-- for simplicity. But to see this in action, consider this example:
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-- function Mnames return Boolean is
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-- procedure Inner is
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-- procedure Inner is
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-- begin
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-- null;
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-- end;
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-- begin
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-- Inner;
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-- end;
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-- function F (A : Boolean) return Boolean is
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-- begin
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-- return not A;
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-- end;
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-- function F (A : Integer) return Boolean is
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-- begin
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-- return A > 42;
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-- end;
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-- begin
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-- Inner;
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-- return F (42) or F (True);
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-- end;
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-- The expanded code actually looks like:
|
|
|
|
-- function mnames return boolean is
|
|
-- procedure mnames__inner is
|
|
-- procedure mnames__inner__inner is
|
|
-- begin
|
|
-- null;
|
|
-- return;
|
|
-- end mnames__inner__inner;
|
|
-- begin
|
|
-- mnames__inner__inner;
|
|
-- return;
|
|
-- end mnames__inner;
|
|
-- function mnames__f (a : boolean) return boolean is
|
|
-- begin
|
|
-- return not a;
|
|
-- end mnames__f;
|
|
-- function mnames__f__2 (a : integer) return boolean is
|
|
-- begin
|
|
-- return a > 42;
|
|
-- end mnames__f__2;
|
|
-- begin
|
|
-- mnames__inner;
|
|
-- return mnames__f__2 (42) or mnames__f (true);
|
|
-- end mnames;
|
|
|
|
-- As can be seen from studying this example, the qualification deals both
|
|
-- with the issue of clashing names (mnames__inner, mnames__inner__inner),
|
|
-- and with overloading (mnames__f, mnames__f__2).
|
|
|
|
-- In addition, the declarations of ARECnT and ARECnPT get moved to the
|
|
-- outer level when we actually generate C code, so we suffix these names
|
|
-- with the corresponding entity name to make sure they are unique.
|
|
|
|
---------------------------
|
|
-- Terminology for Calls --
|
|
---------------------------
|
|
|
|
-- The level of a subprogram in the nest being analyzed is defined to be
|
|
-- the level of nesting, so the outer level subprogram (the one passed to
|
|
-- Unnest_Subprogram) is 1, subprograms immediately nested within this
|
|
-- outer level subprogram have a level of 2, etc.
|
|
|
|
-- Calls within the nest being analyzed are of three types:
|
|
|
|
-- Downward call: this is a call from a subprogram to a subprogram that
|
|
-- is immediately nested with in the caller, and thus has a level that
|
|
-- is one greater than the caller. It is a fundamental property of the
|
|
-- nesting structure and visibility that it is not possible to make a
|
|
-- call from level N to level M, where M is greater than N + 1.
|
|
|
|
-- Parallel call: this is a call from a nested subprogram to another
|
|
-- nested subprogram that is at the same level.
|
|
|
|
-- Upward call: this is a call from a subprogram to a subprogram that
|
|
-- encloses the caller. The level of the callee is less than the level
|
|
-- of the caller, and there is no limit on the difference, e.g. for an
|
|
-- uplevel call, a subprogram at level 5 can call one at level 2 or even
|
|
-- the outer level subprogram at level 1.
|
|
|
|
-----------
|
|
-- Subps --
|
|
-----------
|
|
|
|
-- Table to record subprograms within the nest being currently analyzed.
|
|
-- Entries in this table are made for each subprogram expanded, and do not
|
|
-- get cleared as we complete the expansion, since we want the table info
|
|
-- around in Cprint for the actual unnesting operation. Subps_First in this
|
|
-- unit records the starting entry in the table for the entries for Subp
|
|
-- and this is also recorded in the Subps_Index field of the outer level
|
|
-- subprogram in the nest. The last subps index for the nest can be found
|
|
-- in the Subp_Entry Last field of this first entry.
|
|
|
|
subtype SI_Type is Nat;
|
|
-- Index type for the table
|
|
|
|
Subps_First : SI_Type;
|
|
-- Record starting index for entries in the current nest (this is the table
|
|
-- index of the entry for Subp itself, and is recorded in the Subps_Index
|
|
-- field of the entity for this subprogram).
|
|
|
|
type Subp_Entry is record
|
|
Ent : Entity_Id;
|
|
-- Entity of the subprogram
|
|
|
|
Bod : Node_Id;
|
|
-- Subprogram_Body node for this subprogram
|
|
|
|
Lev : Nat;
|
|
-- Subprogram level (1 = outer subprogram (Subp argument), 2 = nested
|
|
-- immediately within this outer subprogram etc.)
|
|
|
|
Reachable : Boolean;
|
|
-- This flag is set True if there is a call path from the outer level
|
|
-- subprogram to this subprogram. If Reachable is False, it means that
|
|
-- the subprogram is declared but not actually referenced. We remove
|
|
-- such subprograms from the tree, which simplifies our task, because
|
|
-- we don't have to worry about e.g. uplevel references from such an
|
|
-- unreferenced subpogram, which might require (useless) activation
|
|
-- records to be created. This is computed by setting the outer level
|
|
-- subprogram (Subp itself) as reachable, and then doing a transitive
|
|
-- closure following all calls.
|
|
|
|
Uplevel_Ref : Nat;
|
|
-- The outermost level which defines entities which this subprogram
|
|
-- references either directly or indirectly via a call. This cannot
|
|
-- be greater than Lev. If it is equal to Lev, then it means that the
|
|
-- subprogram does not make any uplevel references and that thus it
|
|
-- does not need an activation record pointer passed. If it is less than
|
|
-- Lev, then an activation record pointer is needed, since there is at
|
|
-- least one uplevel reference. This is computed by initially setting
|
|
-- Uplevel_Ref to Lev for all subprograms. Then on the initial tree
|
|
-- traversal, decreasing Uplevel_Ref for an explicit uplevel reference,
|
|
-- and finally by doing a transitive closure that follows calls (if A
|
|
-- calls B and B has an uplevel reference to level X, then A references
|
|
-- level X indirectly).
|
|
|
|
Declares_AREC : Boolean;
|
|
-- This is set True for a subprogram which include the declarations
|
|
-- for a local activation record to be passed on downward calls. It
|
|
-- is set True for the target level of an uplevel reference, and for
|
|
-- all intervening nested subprograms. For example, if a subprogram X
|
|
-- at level 5 makes an uplevel reference to an entity declared in a
|
|
-- level 2 subprogram, then the subprograms at levels 4,3,2 enclosing
|
|
-- the level 5 subprogram will have this flag set True.
|
|
|
|
Uents : Elist_Id;
|
|
-- This is a list of entities declared in this subprogram which are
|
|
-- uplevel referenced. It contains both objects (which will be put in
|
|
-- the corresponding AREC activation record), and types. The types are
|
|
-- not put in the AREC activation record, but referenced bounds (i.e.
|
|
-- generated _FIRST and _LAST entites, and formal parameters) will be
|
|
-- in the list in their own right.
|
|
|
|
Last : SI_Type;
|
|
-- This field is set only in the entry for the outer level subprogram
|
|
-- in a nest, and records the last index in the Subp table for all the
|
|
-- entries for subprograms in this nest.
|
|
|
|
ARECnF : Entity_Id;
|
|
-- This entity is defined for all subprograms which need an extra formal
|
|
-- that contains a pointer to the activation record needed for uplevel
|
|
-- references. ARECnF must be defined for any subprogram which has a
|
|
-- direct or indirect uplevel reference (i.e. Reference_Level < Lev).
|
|
|
|
ARECn : Entity_Id;
|
|
ARECnT : Entity_Id;
|
|
ARECnPT : Entity_Id;
|
|
ARECnP : Entity_Id;
|
|
-- These AREC entities are defined only for subprograms for which we
|
|
-- generate an activation record declaration, i.e. for subprograms for
|
|
-- which the Declares_AREC flag is set True.
|
|
|
|
ARECnU : Entity_Id;
|
|
-- This AREC entity is the uplink component. It is other than Empty only
|
|
-- for nested subprograms that declare an activation record as indicated
|
|
-- by Declares_AREC being Ture, and which have uplevel references (Lev
|
|
-- greater than Uplevel_Ref). It is the additional component in the
|
|
-- activation record that references the ARECnF pointer (which points
|
|
-- the activation record one level higher, thus forming the chain).
|
|
|
|
end record;
|
|
|
|
package Subps is new Table.Table (
|
|
Table_Component_Type => Subp_Entry,
|
|
Table_Index_Type => SI_Type,
|
|
Table_Low_Bound => 1,
|
|
Table_Initial => 1000,
|
|
Table_Increment => 200,
|
|
Table_Name => "Unnest_Subps");
|
|
-- Records the subprograms in the nest whose outer subprogram is Subp
|
|
|
|
-----------------
|
|
-- Subprograms --
|
|
-----------------
|
|
|
|
function Get_Level (Subp : Entity_Id; Sub : Entity_Id) return Nat;
|
|
-- Sub is either Subp itself, or a subprogram nested within Subp. This
|
|
-- function returns the level of nesting (Subp = 1, subprograms that
|
|
-- are immediately nested within Subp = 2, etc.).
|
|
|
|
function Subp_Index (Sub : Entity_Id) return SI_Type;
|
|
-- Given the entity for a subprogram, return corresponding Subp's index
|
|
|
|
procedure Unnest_Subprograms (N : Node_Id);
|
|
-- Called to unnest subprograms. If we are in unnest subprogram mode, this
|
|
-- is the call that traverses the tree N and locates all the library level
|
|
-- subprograms with nested subprograms to process them.
|
|
|
|
end Exp_Unst;
|