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[Ada] Fix wrong code for assignment from overlapping aggregate


This is a regression present on the mainline.  The compiler generates wrong 
code for the assignment to an object of an aggregate that contains a component 
which overlaps with the object, if the object's type is a record type which 
contains at least two nested levels of discriminated record type with default 
discriminant and a component with controlled or tagged type.

Tested on i586-suse-linux, applied on the mainline.


2012-02-27  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/ada-tree.h (TYPE_PACKED_ARRAY_TYPE_P): Add checking.
	(TYPE_BY_REFERENCE_P): New flag.
	(TYPE_IS_BY_REFERENCE_P): New macro.
	(TYPE_DUMMY_P): Add checking and remove VOID_TYPE.
	(TYPE_IS_DUMMY_P): Adjust for above change.
	* gcc-interface/decl.c (gnat_to_gnu_entity): Use TYPE_BY_REFERENCE_P
	and TYPE_IS_BY_REFERENCE_P instead of TREE_ADDRESSABLE.
	(gnat_to_gnu_param): Likewise.
	(maybe_pad_type): Likewise.
	(make_type_from_size): Use TYPE_IS_PACKED_ARRAY_TYPE_P.
	* gcc-interface/misc.c (must_pass_by_ref): Use TYPE_IS_BY_REFERENCE_P
	instead of TREE_ADDRESSABLE.
	* gcc-interface/trans.c (finalize_nrv): Likewise.
	(call_to_gnu): Likewise.  Do not create a temporary for return values
	with by-reference type here.
	(gnat_to_gnu): Test TYPE_IS_DUMMY_P instead of TYPE_DUMMY_P.
	(gnat_gimplify_expr) <ADDR_EXPR>: Don't do anything for non-constant
	CONSTRUCTORs and calls.
	* gcc-interface/utils.c (make_dummy_type): Get the equivalent type of
	the underlying type and use it throughout.  Use TYPE_IS_BY_REFERENCE_P
	instead of TREE_ADDRESSABLE.
	* gcc-interface/utils2.c (build_cond_expr): Deal with by-reference
	types explicitly.


2012-02-27  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/aggr19.adb: New test.
	* gnat.dg/aggr19_pkg.ad[sb]: New helper.


-- 
Eric Botcazou
Index: gcc-interface/utils.c
===================================================================
--- gcc-interface/utils.c	(revision 184585)
+++ gcc-interface/utils.c	(working copy)
@@ -291,7 +291,7 @@ make_dummy_type (Entity_Id gnat_type)
 
   /* If there is an equivalent type, get its underlying type.  */
   if (Present (gnat_underlying))
-    gnat_underlying = Underlying_Type (gnat_underlying);
+    gnat_underlying = Gigi_Equivalent_Type (Underlying_Type (gnat_underlying));
 
   /* If there was no equivalent type (can only happen when just annotating
      types) or underlying type, go back to the original type.  */
@@ -311,8 +311,8 @@ make_dummy_type (Entity_Id gnat_type)
   TYPE_DUMMY_P (gnu_type) = 1;
   TYPE_STUB_DECL (gnu_type)
     = create_type_stub_decl (TYPE_NAME (gnu_type), gnu_type);
-  if (Is_By_Reference_Type (gnat_type))
-    TREE_ADDRESSABLE (gnu_type) = 1;
+  if (Is_By_Reference_Type (gnat_underlying))
+    TYPE_BY_REFERENCE_P (gnu_type) = 1;
 
   SET_DUMMY_NODE (gnat_underlying, gnu_type);
 
Index: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c	(revision 184593)
+++ gcc-interface/decl.c	(working copy)
@@ -4144,7 +4144,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
 	      return_by_invisi_ref_p = true;
 
 	    /* Likewise, if the return type is itself By_Reference.  */
-	    else if (TREE_ADDRESSABLE (gnu_return_type))
+	    else if (TYPE_IS_BY_REFERENCE_P (gnu_return_type))
 	      return_by_invisi_ref_p = true;
 
 	    /* If the type is a padded type and the underlying type would not
@@ -4673,10 +4673,9 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
 	  || Is_Class_Wide_Equivalent_Type (gnat_entity))
 	TYPE_ALIGN_OK (gnu_type) = 1;
 
-      /* If the type is passed by reference, objects of this type must be
-	 fully addressable and cannot be copied.  */
-      if (Is_By_Reference_Type (gnat_entity))
-	TREE_ADDRESSABLE (gnu_type) = 1;
+      /* Record whether the type is passed by reference.  */
+      if (!VOID_TYPE_P (gnu_type) && Is_By_Reference_Type (gnat_entity))
+	TYPE_BY_REFERENCE_P (gnu_type) = 1;
 
       /* ??? Don't set the size for a String_Literal since it is either
 	 confirming or we don't handle it properly (if the low bound is
@@ -5621,7 +5620,7 @@ gnat_to_gnu_param (Entity_Id gnat_param,
 	 parameters whose type isn't by-ref and for which the mechanism hasn't
 	 been forced to by-ref are restrict-qualified in the C sense.  */
       bool restrict_p
-	= !TREE_ADDRESSABLE (gnu_param_type) && mech != By_Reference;
+	= !TYPE_IS_BY_REFERENCE_P (gnu_param_type) && mech != By_Reference;
       gnu_param_type = build_reference_type (gnu_param_type);
       if (restrict_p)
 	gnu_param_type
@@ -6653,7 +6652,7 @@ maybe_pad_type (tree type, tree size, un
   if (align != 0
       && RECORD_OR_UNION_TYPE_P (type)
       && TYPE_MODE (type) == BLKmode
-      && !TREE_ADDRESSABLE (type)
+      && !TYPE_BY_REFERENCE_P (type)
       && TREE_CODE (orig_size) == INTEGER_CST
       && !TREE_OVERFLOW (orig_size)
       && compare_tree_int (orig_size, MAX_FIXED_MODE_SIZE) <= 0
@@ -8353,7 +8352,7 @@ make_type_from_size (tree type, tree siz
 
       /* Only do something if the type is not a packed array type and
 	 doesn't already have the proper size.  */
-      if (TYPE_PACKED_ARRAY_TYPE_P (type)
+      if (TYPE_IS_PACKED_ARRAY_TYPE_P (type)
 	  || (TYPE_PRECISION (type) == size && biased_p == for_biased))
 	break;
 
Index: gcc-interface/utils2.c
===================================================================
--- gcc-interface/utils2.c	(revision 184593)
+++ gcc-interface/utils2.c	(working copy)
@@ -1554,8 +1554,9 @@ build_cond_expr (tree result_type, tree
 
   /* If the result type is unconstrained, take the address of the operands and
      then dereference the result.  Likewise if the result type is passed by
-     reference, but this is natively handled in the gimplifier.  */
+     reference, because creating a temporary of this type is not allowed.  */
   if (TREE_CODE (result_type) == UNCONSTRAINED_ARRAY_TYPE
+      || TYPE_IS_BY_REFERENCE_P (result_type)
       || CONTAINS_PLACEHOLDER_P (TYPE_SIZE (result_type)))
     {
       result_type = build_pointer_type (result_type);
Index: gcc-interface/ada-tree.h
===================================================================
--- gcc-interface/ada-tree.h	(revision 184585)
+++ gcc-interface/ada-tree.h	(working copy)
@@ -80,7 +80,8 @@ do {							 \
 /* For integral types and array types, nonzero if this is a packed array type
    used for bit-packed types.  Such types should not be extended to a larger
    size or validated against a specified size.  */
-#define TYPE_PACKED_ARRAY_TYPE_P(NODE) TYPE_LANG_FLAG_0 (NODE)
+#define TYPE_PACKED_ARRAY_TYPE_P(NODE) \
+  TYPE_LANG_FLAG_0 (TREE_CHECK2 (NODE, INTEGER_TYPE, ARRAY_TYPE))
 
 #define TYPE_IS_PACKED_ARRAY_TYPE_P(NODE) \
   ((TREE_CODE (NODE) == INTEGER_TYPE || TREE_CODE (NODE) == ARRAY_TYPE) \
@@ -108,6 +109,21 @@ do {							 \
    front-end.  */
 #define TYPE_EXTRA_SUBTYPE_P(NODE) TYPE_LANG_FLAG_2 (INTEGER_TYPE_CHECK (NODE))
 
+/* Nonzero for an aggregate type if this is a by-reference type.  We also
+   set this on an ENUMERAL_TYPE that is dummy.  */
+#define TYPE_BY_REFERENCE_P(NODE)				       \
+  TYPE_LANG_FLAG_2 (TREE_CHECK5 (NODE, RECORD_TYPE, UNION_TYPE,	       \
+				 ARRAY_TYPE, UNCONSTRAINED_ARRAY_TYPE, \
+				 ENUMERAL_TYPE))
+
+#define TYPE_IS_BY_REFERENCE_P(NODE)		    \
+  ((TREE_CODE (NODE) == RECORD_TYPE		    \
+    || TREE_CODE (NODE) == UNION_TYPE		    \
+    || TREE_CODE (NODE) == ARRAY_TYPE		    \
+    || TREE_CODE (NODE) == UNCONSTRAINED_ARRAY_TYPE \
+    || TREE_CODE (NODE) == ENUMERAL_TYPE)	    \
+   && TYPE_BY_REFERENCE_P (NODE))
+
 /* For RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE, nonzero if this is the
    type for an object whose type includes its template in addition to
    its value (only true for RECORD_TYPE).  */
@@ -144,13 +160,15 @@ do {							 \
 #define TYPE_RETURN_BY_DIRECT_REF_P(NODE) \
   TYPE_LANG_FLAG_4 (FUNCTION_TYPE_CHECK (NODE))
 
-/* For VOID_TYPE, ENUMERAL_TYPE, UNION_TYPE, and RECORD_TYPE, nonzero if this
-   is a dummy type, made to correspond to a private or incomplete type.  */
-#define TYPE_DUMMY_P(NODE) TYPE_LANG_FLAG_4 (NODE)
-
-#define TYPE_IS_DUMMY_P(NODE) \
-  ((TREE_CODE (NODE) == VOID_TYPE || TREE_CODE (NODE) == RECORD_TYPE	\
-    || TREE_CODE (NODE) == UNION_TYPE || TREE_CODE (NODE) == ENUMERAL_TYPE) \
+/* For RECORD_TYPE, UNION_TYPE and ENUMERAL_TYPE, nonzero if this is a dummy
+   type, made to correspond to a private or incomplete type.  */
+#define TYPE_DUMMY_P(NODE) \
+  TYPE_LANG_FLAG_4 (TREE_CHECK3 (NODE, RECORD_TYPE, UNION_TYPE, ENUMERAL_TYPE))
+
+#define TYPE_IS_DUMMY_P(NODE)		  \
+  ((TREE_CODE (NODE) == RECORD_TYPE	  \
+    || TREE_CODE (NODE) == UNION_TYPE	  \
+    || TREE_CODE (NODE) == ENUMERAL_TYPE) \
    && TYPE_DUMMY_P (NODE))
 
 /* For an INTEGER_TYPE, nonzero if TYPE_ACTUAL_BOUNDS is present.  */
@@ -167,7 +185,7 @@ do {							 \
 /* True if TYPE can alias any other types.  */
 #define TYPE_UNIVERSAL_ALIASING_P(NODE) TYPE_LANG_FLAG_6 (NODE)
 
-/* In an UNCONSTRAINED_ARRAY_TYPE, this is the record containing both the
+/* For an UNCONSTRAINED_ARRAY_TYPE, this is the record containing both the
    template and the object.
 
    ??? We also put this on an ENUMERAL_TYPE that is dummy.  Technically,
Index: gcc-interface/trans.c
===================================================================
--- gcc-interface/trans.c	(revision 184585)
+++ gcc-interface/trans.c	(working copy)
@@ -2654,7 +2654,7 @@ establish_gnat_vms_condition_handler (vo
    on the C++ optimization of the same name.  The main difference is that
    we disregard any semantical considerations when applying it here, the
    counterpart being that we don't try to apply it to semantically loaded
-   return types, i.e. types with the TREE_ADDRESSABLE flag set.
+   return types, i.e. types with the TYPE_BY_REFERENCE_P flag set.
 
    We consider a function body of the following GENERIC form:
 
@@ -3012,7 +3012,7 @@ finalize_nrv (tree fndecl, bitmap nrv, V
 
   /* We shouldn't be applying the optimization to return types that we aren't
      allowed to manipulate freely.  */
-  gcc_assert (!TREE_ADDRESSABLE (TREE_TYPE (TREE_TYPE (fndecl))));
+  gcc_assert (!TYPE_IS_BY_REFERENCE_P (TREE_TYPE (TREE_TYPE (fndecl))));
 
   /* Prune the candidates that are referenced by other return values.  */
   data.nrv = nrv;
@@ -3656,8 +3656,8 @@ call_to_gnu (Node_Id gnat_node, tree *gn
 	  parameters.
 
        2. There is no target and this is not an object declaration, and the
-	  return type is by-reference or has variable size, because in these
-	  cases the gimplifier cannot create the temporary.
+	  return type has variable size, because in these cases the gimplifier
+	  cannot create the temporary.
 
        3. There is a target and it is a slice or an array with fixed size,
 	  and the return type has variable size, because the gimplifier
@@ -3669,8 +3669,7 @@ call_to_gnu (Node_Id gnat_node, tree *gn
       && ((!gnu_target && TYPE_CI_CO_LIST (gnu_subprog_type))
 	  || (!gnu_target
 	      && Nkind (Parent (gnat_node)) != N_Object_Declaration
-	      && (TREE_ADDRESSABLE (gnu_result_type)
-		  || TREE_CODE (TYPE_SIZE (gnu_result_type)) != INTEGER_CST))
+	      && TREE_CODE (TYPE_SIZE (gnu_result_type)) != INTEGER_CST)
 	  || (gnu_target
 	      && (TREE_CODE (gnu_target) == ARRAY_RANGE_REF
 		  || (TREE_CODE (TREE_TYPE (gnu_target)) == ARRAY_TYPE
@@ -3740,7 +3739,7 @@ call_to_gnu (Node_Id gnat_node, tree *gn
 	    ;
 
 	  /* If the type is passed by reference, a copy is not allowed.  */
-	  else if (TREE_ADDRESSABLE (gnu_formal_type))
+	  else if (TYPE_IS_BY_REFERENCE_P (gnu_formal_type))
 	    post_error ("misaligned actual cannot be passed by reference",
 		        gnat_actual);
 
@@ -6786,12 +6785,12 @@ gnat_to_gnu (Node_Id gnat_node)
 					 : NULL_TREE;
 	    tree gnu_target_desig_type = TREE_TYPE (gnu_target_type);
 
-	    if ((TYPE_DUMMY_P (gnu_target_desig_type)
+	    if ((TYPE_IS_DUMMY_P (gnu_target_desig_type)
 		 || get_alias_set (gnu_target_desig_type) != 0)
 		&& (!POINTER_TYPE_P (gnu_source_type)
-		    || (TYPE_DUMMY_P (gnu_source_desig_type)
-			!= TYPE_DUMMY_P (gnu_target_desig_type))
-		    || (TYPE_DUMMY_P (gnu_source_desig_type)
+		    || (TYPE_IS_DUMMY_P (gnu_source_desig_type)
+			!= TYPE_IS_DUMMY_P (gnu_target_desig_type))
+		    || (TYPE_IS_DUMMY_P (gnu_source_desig_type)
 			&& gnu_source_desig_type != gnu_target_desig_type)
 		    || !alias_sets_conflict_p
 			(get_alias_set (gnu_source_desig_type),
@@ -6820,12 +6819,12 @@ gnat_to_gnu (Node_Id gnat_node)
 	    tree gnu_target_array_type
 	      = TREE_TYPE (TREE_TYPE (TYPE_FIELDS (gnu_target_type)));
 
-	    if ((TYPE_DUMMY_P (gnu_target_array_type)
+	    if ((TYPE_IS_DUMMY_P (gnu_target_array_type)
 		 || get_alias_set (gnu_target_array_type) != 0)
 		&& (!TYPE_IS_FAT_POINTER_P (gnu_source_type)
-		    || (TYPE_DUMMY_P (gnu_source_array_type)
-			!= TYPE_DUMMY_P (gnu_target_array_type))
-		    || (TYPE_DUMMY_P (gnu_source_array_type)
+		    || (TYPE_IS_DUMMY_P (gnu_source_array_type)
+			!= TYPE_IS_DUMMY_P (gnu_target_array_type))
+		    || (TYPE_IS_DUMMY_P (gnu_source_array_type)
 			&& gnu_source_array_type != gnu_target_array_type)
 		    || !alias_sets_conflict_p
 			(get_alias_set (gnu_source_array_type),
@@ -7334,23 +7333,6 @@ gnat_gimplify_expr (tree *expr_p, gimple
 	  return GS_ALL_DONE;
 	}
 
-      /* Otherwise, if we are taking the address of a non-constant CONSTRUCTOR
-	 or of a call, explicitly create the local temporary.  That's required
-	 if the type is passed by reference.  */
-      if (TREE_CODE (op) == CONSTRUCTOR || TREE_CODE (op) == CALL_EXPR)
-	{
-	  tree mod, new_var = create_tmp_var_raw (TREE_TYPE (op), "C");
-	  TREE_ADDRESSABLE (new_var) = 1;
-	  gimple_add_tmp_var (new_var);
-
-	  mod = build2 (INIT_EXPR, TREE_TYPE (new_var), new_var, op);
-	  gimplify_and_add (mod, pre_p);
-
-	  TREE_OPERAND (expr, 0) = new_var;
-	  recompute_tree_invariant_for_addr_expr (expr);
-	  return GS_ALL_DONE;
-	}
-
       return GS_UNHANDLED;
 
     case VIEW_CONVERT_EXPR:
Index: gcc-interface/misc.c
===================================================================
--- gcc-interface/misc.c	(revision 184585)
+++ gcc-interface/misc.c	(working copy)
@@ -6,7 +6,7 @@
  *                                                                          *
  *                           C Implementation File                          *
  *                                                                          *
- *          Copyright (C) 1992-2011, Free Software Foundation, Inc.         *
+ *          Copyright (C) 1992-2012, 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- *
@@ -624,7 +624,7 @@ must_pass_by_ref (tree gnu_type)
      and does not produce compatibility problems with C, since C does
      not have such objects.  */
   return (TREE_CODE (gnu_type) == UNCONSTRAINED_ARRAY_TYPE
-	  || TREE_ADDRESSABLE (gnu_type)
+	  || TYPE_IS_BY_REFERENCE_P (gnu_type)
 	  || (TYPE_SIZE (gnu_type)
 	      && TREE_CODE (TYPE_SIZE (gnu_type)) != INTEGER_CST));
 }
-- { dg-do run }

with Aggr19_Pkg; use Aggr19_Pkg;

procedure Aggr19 is
  C : Rec5
    := (Ent => (Kind => Two, Node => (L => (D => True, Pos => 1 )), I => 0));
  A : Rec5 := C;
begin
  Proc (A);
  if A /= C then
    raise Program_Error;
  end if;
end;
package Aggr19_Pkg is

  type Rec1 (D : Boolean := False) is record
    case D is
      when False => null;
      when True => Pos : Integer;
    end case;
  end record;

  type Rec2 is record
    L : Rec1;
  end record;

  type Rec3 is tagged null record;

  type Enum is (One, Two, Three);

  type Rec4 (Kind : Enum := One) is record
    Node : Rec2;
    case Kind is
      when One => R : Rec3;
      when Others => I : Integer;
    end case;
  end record;

  type Rec5 is record
    Ent : Rec4;
  end record;

  procedure Proc (Pool : in out Rec5);

end Aggr19_Pkg;
package body Aggr19_Pkg is

  procedure Proc (Pool : in out Rec5) is
  begin
    Pool.Ent := (Kind => Two, Node => Pool.Ent.Node, I => 0);
  end;

end ;

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