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[Ada] Add another check for SSO compatibility

Message ID 4637376.09HO3za1EB@polaris
State New
Headers show

Commit Message

Eric Botcazou Feb. 24, 2017, 11:03 a.m. UTC 
When removing the wrapper around a justified modular type used to implement a 
packed array type.  This shouldn't make any difference because the front-end 
is supposed to filter out this case so it's for the sake of robustness.

Tested on x86_64-suse-linux, applied on mainline and 6 branch.


2017-02-24  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/decl.c (gnat_to_gnu_field): Do not remove the wrapper
	around a justified modular type if it doesn't have the same scalar
	storage order as the enclosing record type.
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Patch

Index: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c	(revision 245700)
+++ gcc-interface/decl.c	(working copy)
@@ -7031,6 +7031,7 @@  static tree
 gnat_to_gnu_field (Entity_Id gnat_field, tree gnu_record_type, int packed,
 		   bool definition, bool debug_info_p)
 {
+  const Entity_Id gnat_record_type = Underlying_Type (Scope (gnat_field));
   const Entity_Id gnat_field_type = Etype (gnat_field);
   const bool is_aliased
     = Is_Aliased (gnat_field);
@@ -7117,8 +7118,7 @@  gnat_to_gnu_field (Entity_Id gnat_field,
   if (Present (Component_Clause (gnat_field)))
     {
       Node_Id gnat_clause = Component_Clause (gnat_field);
-      Entity_Id gnat_parent
-	= Parent_Subtype (Underlying_Type (Scope (gnat_field)));
+      Entity_Id gnat_parent = Parent_Subtype (gnat_record_type);
 
       gnu_pos = UI_To_gnu (Component_Bit_Offset (gnat_field), bitsizetype);
       gnu_size = validate_size (Esize (gnat_field), gnu_field_type,
@@ -7237,7 +7237,7 @@  gnat_to_gnu_field (Entity_Id gnat_field,
 
   /* If the record has rep clauses and this is the tag field, make a rep
      clause for it as well.  */
-  else if (Has_Specified_Layout (Scope (gnat_field))
+  else if (Has_Specified_Layout (gnat_record_type)
 	   && Chars (gnat_field) == Name_uTag)
     {
       gnu_pos = bitsize_zero_node;
@@ -7274,11 +7274,14 @@  gnat_to_gnu_field (Entity_Id gnat_field,
       /* If the field's type is justified modular, we would need to remove
 	 the wrapper to (better) meet the layout requirements.  However we
 	 can do so only if the field is not aliased to preserve the unique
-	 layout and if the prescribed size is not greater than that of the
-	 packed array to preserve the justification.  */
+	 layout, if it has the same storage order as the enclosing record
+	 and if the prescribed size is not greater than that of the packed
+	 array to preserve the justification.  */
       if (!needs_strict_alignment
 	  && TREE_CODE (gnu_field_type) == RECORD_TYPE
 	  && TYPE_JUSTIFIED_MODULAR_P (gnu_field_type)
+	  && TYPE_REVERSE_STORAGE_ORDER (gnu_field_type)
+	     == Reverse_Storage_Order (gnat_record_type)
 	  && tree_int_cst_compare (gnu_size, TYPE_ADA_SIZE (gnu_field_type))
 	       <= 0)
 	gnu_field_type = TREE_TYPE (TYPE_FIELDS (gnu_field_type));