re PR c/24255 (__transparent_union__ mishandled)

        PR c/24255
        * tree.h (DECL_TRANSPARENT_UNION): Remove.
        * function.c (assign_parm_find_data_types): Don't support it.
        * print-tree.c (print_node): Likewise.
        * c-common.c (handle_transparent_union_attribute): Likewise.
        Use build_duplicate_type.
        * tree-inline.c (remap_type_1): Split out of remap_type;
        properly remap aggregate fields.
        (build_duplicate_type): New.
        * doc/extend.texi (Variable Attributes): Remove documentation
        for transparent_union.

From-SVN: r105338

7 files changed, 102 insertions, 64 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index abf8908..308be618 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,17 @@
+2005-10-12  Richard Henderson  <rth@redhat.com>
+
+	PR c/24255
+	* tree.h (DECL_TRANSPARENT_UNION): Remove.
+	* function.c (assign_parm_find_data_types): Don't support it.
+	* print-tree.c (print_node): Likewise.
+	* c-common.c (handle_transparent_union_attribute): Likewise.
+	Use build_duplicate_type.
+	* tree-inline.c (remap_type_1): Split out of remap_type;
+	properly remap aggregate fields.
+	(build_duplicate_type): New.
+	* doc/extend.texi (Variable Attributes): Remove documentation
+	for transparent_union.
+
 2005-10-12  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
 	PR target/24284
diff --git a/gcc/c-common.c b/gcc/c-common.c
index 4114fbf..c5b409e 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -4309,39 +4309,43 @@ handle_transparent_union_attribute (tree *node, tree name,
 				    tree ARG_UNUSED (args), int flags,
 				    bool *no_add_attrs)
 {
-  tree decl = NULL_TREE;
-  tree *type = NULL;
-  int is_type = 0;
+  tree type = NULL;
+
+  *no_add_attrs = true;
 
   if (DECL_P (*node))
     {
-      decl = *node;
-      type = &TREE_TYPE (decl);
-      is_type = TREE_CODE (*node) == TYPE_DECL;
+      if (TREE_CODE (*node) != TYPE_DECL)
+	goto ignored;
+      node = &TREE_TYPE (*node);
+      type = *node;
     }
   else if (TYPE_P (*node))
-    type = node, is_type = 1;
+    type = *node;
+  else
+    goto ignored;
 
-  if (is_type
-      && TREE_CODE (*type) == UNION_TYPE
-      && (decl == 0
-	  || (TYPE_FIELDS (*type) != 0
-	      && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))))
+  if (TREE_CODE (type) == UNION_TYPE)
     {
+      /* When IN_PLACE is set, leave the check for FIELDS and MODE to
+	 the code in finish_struct.  */
       if (!(flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
-	*type = build_variant_type_copy (*type);
-      TYPE_TRANSPARENT_UNION (*type) = 1;
-    }
-  else if (decl != 0 && TREE_CODE (decl) == PARM_DECL
-	   && TREE_CODE (*type) == UNION_TYPE
-	   && TYPE_MODE (*type) == DECL_MODE (TYPE_FIELDS (*type)))
-    DECL_TRANSPARENT_UNION (decl) = 1;
-  else
-    {
-      warning (OPT_Wattributes, "%qE attribute ignored", name);
-      *no_add_attrs = true;
+	{
+	  if (TYPE_FIELDS (type) == NULL_TREE
+	      || TYPE_MODE (type) != DECL_MODE (TYPE_FIELDS (type)))
+	    goto ignored;
+
+	  /* A type variant isn't good enough, since we don't a cast
+	     to such a type removed as a no-op.  */
+	  *node = type = build_duplicate_type (type);
+	}
+
+      TYPE_TRANSPARENT_UNION (type) = 1;
+      return NULL_TREE;
     }
 
+ ignored:
+  warning (OPT_Wattributes, "%qE attribute ignored", name);
   return NULL_TREE;
 }
 
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 71518e4..52a8cc2 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -3019,14 +3019,6 @@ The @var{tls_model} argument should be one of @code{global-dynamic},
 
 Not all targets support this attribute.
 
-@item transparent_union
-This attribute, attached to a function parameter which is a union, means
-that the corresponding argument may have the type of any union member,
-but the argument is passed as if its type were that of the first union
-member.  For more details see @xref{Type Attributes}.  You can also use
-this attribute on a @code{typedef} for a union data type; then it
-applies to all function parameters with that type.
-
 @item unused
 This attribute, attached to a variable, means that the variable is meant
 to be possibly unused.  GCC will not produce a warning for this
diff --git a/gcc/function.c b/gcc/function.c
index 2df1eff..7cff2a0 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -2013,9 +2013,8 @@ assign_parm_find_data_types (struct assign_parm_data_all *all, tree parm,
   /* If the parm is to be passed as a transparent union, use the type of
      the first field for the tests below.  We have already verified that
      the modes are the same.  */
-  if (DECL_TRANSPARENT_UNION (parm)
-      || (TREE_CODE (passed_type) == UNION_TYPE
-	  && TYPE_TRANSPARENT_UNION (passed_type)))
+  if (TREE_CODE (passed_type) == UNION_TYPE
+      && TYPE_TRANSPARENT_UNION (passed_type))
     passed_type = TREE_TYPE (TYPE_FIELDS (passed_type));
 
   /* See if this arg was passed by invisible reference.  */
diff --git a/gcc/print-tree.c b/gcc/print-tree.c
index ddc370b..9a8a5bb7 100644
--- a/gcc/print-tree.c
+++ b/gcc/print-tree.c
@@ -385,9 +385,6 @@ print_node (FILE *file, const char *prefix, tree node, int indent)
 	    }
 	}
 
-      if (TREE_CODE (node) == PARM_DECL && DECL_TRANSPARENT_UNION (node))
-	fputs (" transparent-union", file);
-
       if (DECL_VIRTUAL_P (node))
 	fputs (" virtual", file);
       if (CODE_CONTAINS_STRUCT (code, TS_DECL_WITH_VIS)  && DECL_DEFER_OUTPUT (node))
diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
index f22785c..0f7ea97 100644
--- a/gcc/tree-inline.c
+++ b/gcc/tree-inline.c
@@ -257,26 +257,10 @@ remap_decl (tree decl, inline_data *id)
 }
 
 static tree
-remap_type (tree type, inline_data *id)
+remap_type_1 (tree type, inline_data *id)
 {
-  splay_tree_node node;
   tree new, t;
 
-  if (type == NULL)
-    return type;
-
-  /* See if we have remapped this type.  */
-  node = splay_tree_lookup (id->decl_map, (splay_tree_key) type);
-  if (node)
-    return (tree) node->value;
-
-  /* The type only needs remapping if it's variably modified.  */
-  if (! variably_modified_type_p (type, id->callee))
-    {
-      insert_decl_map (id, type, type);
-      return type;
-    }
-
   /* We do need a copy.  build and register it now.  If this is a pointer or
      reference type, remap the designated type and make a new pointer or
      reference type.  */
@@ -353,7 +337,18 @@ remap_type (tree type, inline_data *id)
     case RECORD_TYPE:
     case UNION_TYPE:
     case QUAL_UNION_TYPE:
-      walk_tree (&TYPE_FIELDS (new), copy_body_r, id, NULL);
+      {
+	tree f, nf = NULL;
+
+	for (f = TYPE_FIELDS (new); f ; f = TREE_CHAIN (f))
+	  {
+	    t = remap_decl (f, id);
+	    DECL_CONTEXT (t) = new;
+	    TREE_CHAIN (t) = nf;
+	    nf = t;
+	  }
+	TYPE_FIELDS (new) = nreverse (nf);
+      }
       break;
 
     case OFFSET_TYPE:
@@ -369,6 +364,29 @@ remap_type (tree type, inline_data *id)
 }
 
 static tree
+remap_type (tree type, inline_data *id)
+{
+  splay_tree_node node;
+
+  if (type == NULL)
+    return type;
+
+  /* See if we have remapped this type.  */
+  node = splay_tree_lookup (id->decl_map, (splay_tree_key) type);
+  if (node)
+    return (tree) node->value;
+
+  /* The type only needs remapping if it's variably modified.  */
+  if (! variably_modified_type_p (type, id->callee))
+    {
+      insert_decl_map (id, type, type);
+      return type;
+    }
+
+  return remap_type_1 (type, id);
+}
+
+static tree
 remap_decls (tree decls, inline_data *id)
 {
   tree old_var;
@@ -2959,3 +2977,23 @@ inlining_p (inline_data * id)
 {
   return (!id->saving_p && !id->cloning_p && !id->versioning_p);
 }
+
+/* Duplicate a type, fields and all.  */
+
+tree
+build_duplicate_type (tree type)
+{
+  inline_data id;
+
+  memset (&id, 0, sizeof (id));
+  id.callee = current_function_decl;
+  id.caller = current_function_decl;
+  id.callee_cfun = cfun;
+  id.decl_map = splay_tree_new (splay_tree_compare_pointers, NULL, NULL);
+
+  type = remap_type_1 (type, &id);
+
+  splay_tree_delete (id.decl_map);
+
+  return type;
+}
diff --git a/gcc/tree.h b/gcc/tree.h
index 144dbd8..f54f6d3 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -2199,12 +2199,11 @@ struct tree_decl_common GTY(())
   /* In LABEL_DECL, this is DECL_ERROR_ISSUED.
      In VAR_DECL and PARM_DECL, this is DECL_REGISTER.  */
   unsigned decl_flag_0 : 1;
-  /* In FIELD_DECL, this is DECL_PACKED
-     In PARM_DECL, this is DECL_TRANSPARENT_UNION.  */
+  /* In FIELD_DECL, this is DECL_PACKED.  */
   unsigned decl_flag_1 : 1;
   /* In FIELD_DECL, this is DECL_BIT_FIELD
      In VAR_DECL and FUNCTION_DECL, this is DECL_EXTERNAL. 
-     In TYPE_DECL, this is TYPE_DECL_SUPRESS_DEBUG*/  
+     In TYPE_DECL, this is TYPE_DECL_SUPRESS_DEBUG.  */  
   unsigned decl_flag_2 : 1;  
   /* In FIELD_DECL, this is DECL_NONADDRESSABLE_P
      In VAR_DECL and PARM_DECL, this is DECL_HAS_VALUE_EXPR.  */
@@ -2386,12 +2385,6 @@ struct tree_const_decl GTY(())
    where the data was actually passed.  */
 #define DECL_INCOMING_RTL(NODE) (PARM_DECL_CHECK (NODE)->parm_decl.incoming_rtl)
 
-/* Used in PARM_DECLs whose type are unions to indicate that the
-   argument should be passed in the same way that the first union
-   alternative would be passed.  */
-#define DECL_TRANSPARENT_UNION(NODE) \
-  (PARM_DECL_CHECK (NODE)->decl_common.decl_flag_1)
-
 struct tree_parm_decl GTY(())
 {
   struct tree_decl_with_rtl common;
@@ -3989,6 +3982,7 @@ extern bool debug_find_tree (tree, tree);
 /* This is in tree-inline.c since the routine uses
    data structures from the inliner.  */
 extern tree unsave_expr_now (tree);
+extern tree build_duplicate_type (tree);
 
 /* In emit-rtl.c */
 extern rtx emit_line_note (location_t);