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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- L O C A L _ R E S T R I C T --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2024, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Aspects; use Aspects;
with Atree; use Atree;
with Einfo; use Einfo;
with Einfo.Entities; use Einfo.Entities;
with Einfo.Utils; use Einfo.Utils;
with Errout; use Errout;
with Lib; use Lib;
with Restrict; use Restrict;
with Rident; use Rident;
with Sem_Aux; use Sem_Aux;
with Sem_Ch13; use Sem_Ch13;
with Sem_Util; use Sem_Util;
with Sinfo.Nodes; use Sinfo.Nodes;
with Sinfo.Utils; use Sinfo.Utils;
package body Local_Restrict is
function L_R_Image (L_R : Local_Restriction) return String is
(case L_R is when No_Secondary_Stack => "No_Secondary_Stack",
when No_Heap_Allocations => "No_Heap_Allocations");
-- Like Local_Restriction'Image, but with casing appropriate for
-- error messages.
function Active_Restriction
(L_R : Local_Restriction; E : Entity_Id := Current_Scope) return Node_Id;
-- Returns the Local_Restrictions aspect specification that is in effect
-- for E and that imposes the given local restriction; returns Empty if
-- no such aspect specification exists.
procedure Check_For_Corresponding_Local_Restriction
(Violated : All_Restrictions; N : Node_Id);
-- Generate error for node N if a violation of the given (non-local)
-- restriction implies a violation of a corresponding local restriction
-- that is in effect.
procedure Check_For_Local_Restriction
(L_R : Local_Restriction; N : Node_Id);
-- Generate error for node N if given restriction is in effect.
------------------------
-- Active_Restriction --
------------------------
function Active_Restriction
(L_R : Local_Restriction; E : Entity_Id := Current_Scope) return Node_Id
is
Scop : Node_Id := E;
Result : Node_Id;
begin
-- If performance of this function becomes a problem then
-- one possible solution would be cache a set of scopes
-- for which it is known that no local restrictions apply.
-- Perhaps with fixed size (maybe 8?) and LRU replacement?
--
-- Or perhaps just a single global Boolean indicating that
-- no Local_Restrictions aspect specification has been seen
-- at any time in any context during the current compilation.
-- If the flag is set, then Active_Restriction returns Empty
-- without any looping.
while Present (Scop) loop
Result := Find_Aspect (Scop, Aspect_Local_Restrictions);
if Present (Result)
and then Parse_Aspect_Local_Restrictions (Result) (L_R)
then
return Result;
end if;
Scop := Enclosing_Declaration (Scop);
if Present (Scop) then
Scop := Parent (Scop);
if Present (Scop) then
-- For a subprogram associated with a type, we don't care
-- where the type was frozen; continue from the type.
if Nkind (Scop) = N_Freeze_Entity then
Scop := Scope (Entity (Scop));
elsif Nkind (Parent (Scop)) = N_Freeze_Entity then
Scop := Scope (Entity (Parent (Scop)));
else
Scop := Find_Enclosing_Scope (Scop);
end if;
end if;
end if;
end loop;
return Empty;
end Active_Restriction;
-----------------------------------------------
-- Check_For_Corresponding_Local_Restriction --
-----------------------------------------------
procedure Check_For_Corresponding_Local_Restriction
(Violated : All_Restrictions; N : Node_Id)
is
L_R : Local_Restriction;
begin
-- Some restrictions map to a corresponding local restriction.
-- In those cases, check whether the local restriction is in effect.
-- This is the point at which the specific semantics of each
-- local restriction is effectively defined.
case Violated is
when No_Secondary_Stack =>
L_R := No_Secondary_Stack;
when No_Allocators | No_Implicit_Heap_Allocations =>
L_R := No_Heap_Allocations;
when others =>
return;
end case;
Check_For_Local_Restriction (L_R, N);
end Check_For_Corresponding_Local_Restriction;
---------------------------------
-- Check_For_Local_Restriction --
---------------------------------
procedure Check_For_Local_Restriction
(L_R : Local_Restriction; N : Node_Id)
is
L_R_Aspect_Spec : constant Node_Id := Active_Restriction (L_R);
begin
if Present (L_R_Aspect_Spec) then
Error_Msg_Sloc := Sloc (L_R_Aspect_Spec);
Error_Msg_N
("violation of local restriction " & L_R_Image (L_R) & "#", N);
end if;
end Check_For_Local_Restriction;
----------------
-- Check_Call --
----------------
procedure Check_Call (Call : Node_Id; Callee : Entity_Id := Empty) is
Restrictions_Enforced_By_Callee : Local_Restriction_Set :=
(others => False);
Real_Callee : Entity_Id;
begin
if Present (Callee) then
Real_Callee := Ultimate_Alias (Callee);
if Is_Intrinsic_Subprogram (Real_Callee)
or else In_Predefined_Unit (Real_Callee)
then
-- If an intrinsic or predefined subprogram violates a local
-- restriction then we don't catch it here. For that, we rely
-- on the same mechanism that is used to catch violations of
-- the corresponding global restriction (i.e., the
-- Local_Restriction_Checking_Hook call in Check_Restriction).
return;
end if;
for L_R in Local_Restriction loop
if Present (Active_Restriction (L_R, Real_Callee)) then
Restrictions_Enforced_By_Callee (L_R) := True;
end if;
end loop;
end if;
for L_R in Local_Restriction loop
if not Restrictions_Enforced_By_Callee (L_R) then
-- Complain if caller must enforce L_R and callee
-- does not promise to do that.
Check_For_Local_Restriction (L_R, Call);
end if;
end loop;
end Check_Call;
-----------------------
-- Check_Overriding --
-----------------------
procedure Check_Overriding (Overrider_Op, Overridden_Op : Entity_Id) is
Ultimate_Overrider : constant Entity_Id :=
Ultimate_Alias (Overrider_Op);
Ultimate_Overridden : constant Entity_Id :=
Ultimate_Alias (Overridden_Op);
begin
-- a minor optimization
if Ultimate_Overrider = Ultimate_Overridden then
return;
end if;
for L_R in Local_Restriction loop
if Present (Active_Restriction (L_R, Ultimate_Overridden))
and then No (Active_Restriction (L_R, Ultimate_Overrider))
then
Error_Msg_Sloc :=
Sloc (Active_Restriction (L_R, Ultimate_Overridden));
Error_Msg_N
("overriding incompatible with local restriction " &
L_R_Image (L_R) & "#",
Ultimate_Overrider);
end if;
end loop;
end Check_Overriding;
------------------------------------------
-- Check_Actual_Subprogram_For_Instance --
------------------------------------------
procedure Check_Actual_Subprogram_For_Instance
(Actual_Subp_Name : Node_Id; Formal_Subp : Entity_Id)
is
Actual_Subp : Entity_Id := Empty;
begin
if Is_Entity_Name (Actual_Subp_Name) then
Actual_Subp := Entity (Actual_Subp_Name);
end if;
for L_R in Local_Restriction loop
-- Complain if some local restriction is in effect for
-- the formal subprogram but not for the actual subprogram.
if Present (Active_Restriction (L_R, Formal_Subp))
and then
(No (Actual_Subp)
or else No (Active_Restriction (L_R, Actual_Subp)))
then
Error_Msg_Sloc := Sloc (Active_Restriction (L_R, Formal_Subp));
Error_Msg_N
("actual subprogram incompatible with local restriction " &
L_R_Image (L_R) & " #",
Actual_Subp_Name);
end if;
end loop;
end Check_Actual_Subprogram_For_Instance;
begin
-- Allow package Restrict to call package Local_Restrict without
-- pulling the bulk of semantics into the closure of package Restrict.
--
-- For example, if an allocator is encountered, then package
-- Restrict is called to check whether a No_Allocators restriction is
-- in effect. At that point, we also want to check whether a
-- No_Heap_Allocations local restriction is in effect. This
-- registration makes that possible.
Local_Restrictions.Local_Restriction_Checking_Hook :=
Check_For_Corresponding_Local_Restriction'Access;
end Local_Restrict;
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