exp_ch5.adb (Expand_N_Extended_Return_Statement): Suppress generation of a heap…

exp_ch5.adb (Expand_N_Extended_Return_Statement): Suppress generation of a heap allocator for a limited unconstrained function...

2008-03-26  Gary Dismukes  <dismukes@adacore.com>

	* exp_ch5.adb (Expand_N_Extended_Return_Statement): Suppress generation
	of a heap allocator for a limited unconstrained function return when
	resstriction No_Allocators is active.
	(Analyze_Allocator): The restriction No_Allocators is now only checked
	on allocators that have Comes_From_Source set, as per RM-H.4(7).

	* sem_ch4.adb (Expand_N_Extended_Return_Statement): Suppress generation
	of a heap allocator for a limited unconstrained function return when
	resstriction No_Allocators is active.
	(Analyze_Allocator): The restriction No_Allocators is now only checked
	on allocators that have Comes_From_Source set, as per RM-H.4(7).
	(Has_Fixed_Op):  If the name in a function call is Standard."*" and the
	operands are fixed-point types, the universal_fixed predefined operation
	is used, regardless of whether the operand type (s) have a primitive
	operation of the same name.

From-SVN: r133563

gcc/ada/exp_ch5.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 1992-2007, Free Software Foundation, Inc.         --
+--          Copyright (C) 1992-2008, 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- --
@@ -2792,6 +2792,30 @@ package body Exp_Ch5 is
                         SS_Allocator := New_Copy_Tree (Heap_Allocator);
                      end if;
 
+                     --  If the No_Allocators restriction is active, then only
+                     --  an allocator for secondary stack allocation is needed.
+
+                     if Restriction_Active (No_Allocators) then
+                        SS_Allocator   := Heap_Allocator;
+                        Heap_Allocator := Make_Null (Loc);
+
+                     --  Otherwise the heap allocator may be needed, so we
+                     --  make another allocator for secondary stack allocation.
+
+                     else
+                        SS_Allocator := New_Copy_Tree (Heap_Allocator);
+
+                        --  The heap allocator is marked Comes_From_Source
+                        --  since it corresponds to an explicit user-written
+                        --  allocator (that is, it will only be executed on
+                        --  behalf of callers that call the function as
+                        --  initialization for such an allocator). This
+                        --  prevents errors when No_Implicit_Heap_Allocation
+                        --  is in force.
+
+                        Set_Comes_From_Source (Heap_Allocator, True);
+                     end if;
+
                      --  The allocator is returned on the secondary stack. We
                      --  don't do this on VM targets, since the SS is not used.
 

gcc/ada/sem_ch4.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 1992-2007, Free Software Foundation, Inc.         --
+--          Copyright (C) 1992-2008, 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- --
@@ -356,7 +356,12 @@ package body Sem_Ch4 is
       Type_Id  : Entity_Id;
 
    begin
-      Check_Restriction (No_Allocators, N);
+      --  In accordance with H.4(7), the No_Allocators restriction only applies
+      --  to user-written allocators.
+
+      if Comes_From_Source (N) then
+         Check_Restriction (No_Allocators, N);
+      end if;
 
       if Nkind (E) = N_Qualified_Expression then
          Acc_Type := Create_Itype (E_Allocator_Type, N);
@@ -3811,6 +3816,10 @@ package body Sem_Ch4 is
       --  predefined operator. Used to implement Ada 2005 AI-264, to make
       --  such operators more visible and therefore useful.
 
+      --  If the name of the operation is an expanded name with prefix
+      --  Standard, the predefined universal fixed operator is available,
+      --  as specified by AI-420 (RM 4.5.5 (19.1/2)).
+
       function Specific_Type (T1, T2 : Entity_Id) return Entity_Id;
       --  Get specific type (i.e. non-universal type if there is one)
 
@@ -3825,6 +3834,16 @@ package body Sem_Ch4 is
          F2  : Entity_Id;
 
       begin
+         --  If the universal_fixed operation is given explicitly the rule
+         --  concerning primitive operations of the type do not apply.
+
+         if Nkind (N) = N_Function_Call
+           and then Nkind (Name (N)) = N_Expanded_Name
+           and then Entity (Prefix (Name (N))) = Standard_Standard
+         then
+            return False;
+         end if;
+
          --  The operation is treated as primitive if it is declared in the
          --  same scope as the type, and therefore on the same entity chain.