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PR c/21342
[pf3gnuchains/gcc-fork.git] / gcc / c-decl.c
index e7ac0d3..0ca4500 100644 (file)
@@ -2029,11 +2029,52 @@ pushdecl (tree x)
   b = I_SYMBOL_BINDING (name);
   if (b && B_IN_SCOPE (b, scope))
     {
+      struct c_binding *b_ext, *b_use;
+      tree type = TREE_TYPE (x);
+      tree visdecl = b->decl;
+      tree vistype = TREE_TYPE (visdecl);
       if (TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE
          && COMPLETE_TYPE_P (TREE_TYPE (x)))
        b->inner_comp = false;
-      if (duplicate_decls (x, b->decl))
-       return b->decl;
+      b_use = b;
+      b_ext = b;
+      /* If this is an external linkage declaration, we should check
+        for compatibility with the type in the external scope before
+        setting the type at this scope based on the visible
+        information only.  */
+      if (TREE_PUBLIC (x) && TREE_PUBLIC (visdecl))
+       {
+         while (b_ext && !B_IN_EXTERNAL_SCOPE (b_ext))
+           b_ext = b_ext->shadowed;
+         if (b_ext)
+           {
+             b_use = b_ext;
+             if (b_use->type)
+               TREE_TYPE (b_use->decl) = b_use->type;
+           }
+       }
+      if (duplicate_decls (x, b_use->decl))
+       {
+         if (b_use != b)
+           {
+             /* Save the updated type in the external scope and
+                restore the proper type for this scope.  */
+             tree thistype;
+             if (comptypes (vistype, type))
+               thistype = composite_type (vistype, type);
+             else
+               thistype = TREE_TYPE (b_use->decl);
+             b_use->type = TREE_TYPE (b_use->decl);
+             if (TREE_CODE (b_use->decl) == FUNCTION_DECL
+                 && DECL_BUILT_IN (b_use->decl))
+               thistype
+                 = build_type_attribute_variant (thistype,
+                                                 TYPE_ATTRIBUTES
+                                                 (b_use->type));
+             TREE_TYPE (b_use->decl) = thistype;
+           }
+         return b_use->decl;
+       }
       else
        goto skip_external_and_shadow_checks;
     }
@@ -2120,7 +2161,15 @@ pushdecl (tree x)
          && duplicate_decls (x, b->decl))
        {
          tree thistype;
-         thistype = (vistype ? composite_type (vistype, type) : type);
+         if (vistype)
+           {
+             if (comptypes (vistype, type))
+               thistype = composite_type (vistype, type);
+             else
+               thistype = TREE_TYPE (b->decl);
+           }
+         else
+           thistype = type;
          b->type = TREE_TYPE (b->decl);
          if (TREE_CODE (b->decl) == FUNCTION_DECL && DECL_BUILT_IN (b->decl))
            thistype