cgraph.h (struct varpool_node): new used_from_object_file flag.

2010-06-28  Bingfeng Mei <bmei@broadcom.com>

        * cgraph.h (struct varpool_node): new used_from_object_file flag.
        (struct cgraph_local_info): new used_from_object_file flag.
        * cgraph.c (dump_cgraph_node): dump used_from_object_file flag.
        (cgraph_clone_node): initialize used_from_object_file.
        (cgraph_create_virtual_clone): initialize used_from_object_file.
        * lto-symbtab.c (lto_symtab_merge_decls_1): Set
        used_from_object_file flags for symbols of LDPR_PREVAILING_DEF
        when compiling with -fwhole-program.
        (lto_symtab_resolve_symbols) Use LDPR_PREVAILING_DEF_IRONLY for
	internal resolver.
        * ipa.c (function_and_variable_visibility): Set externally_visible
        flag of varpool_node if used_from_object_file flag is set.
        (cgraph_externally_visible_p): check used_from_object_file flag.
        * doc/invoke.texi (-fwhole-program option): Change description of
        externally_visible attribute accordingly.
        * doc/extend.texi (externally_visible): Ditto.

From-SVN: r161483

1 files changed, 31 insertions, 4 deletions

diff --git a/gcc/lto-symtab.c b/gcc/lto-symtab.c
index 6f46a73..e94bc20 100644
--- a/gcc/lto-symtab.c
+++ b/gcc/lto-symtab.c
@@ -530,11 +530,20 @@ lto_symtab_resolve_symbols (void **slot)
     return;
 
 found:
-  if (TREE_CODE (prevailing->decl) == VAR_DECL
-      && TREE_READONLY (prevailing->decl))
+  /* If current lto files represent the whole program,
+    it is correct to use LDPR_PREVALING_DEF_IRONLY.
+    If current lto files are part of whole program, internal
+    resolver doesn't know if it is LDPR_PREVAILING_DEF
+    or LDPR_PREVAILING_DEF_IRONLY.  Use IRONLY conforms to
+    using -fwhole-program.  Otherwise, it doesn't
+    matter using either LDPR_PREVAILING_DEF or
+    LDPR_PREVAILING_DEF_IRONLY
+    
+    FIXME: above workaround due to gold plugin makes some
+    variables IRONLY, which are indeed PREVAILING_DEF in
+    resolution file.  These variables still need manual
+    externally_visible attribute.  */
     prevailing->resolution = LDPR_PREVAILING_DEF_IRONLY;
-  else
-    prevailing->resolution = LDPR_PREVAILING_DEF;
 }
 
 /* Merge all decls in the symbol table chain to the prevailing decl and
@@ -698,6 +707,24 @@ lto_symtab_merge_decls_1 (void **slot, void *data ATTRIBUTE_UNUSED)
       && TREE_CODE (prevailing->decl) != VAR_DECL)
     prevailing->next = NULL;
 
+  /* Set externally_visible flags for declaration of LDPR_PREVAILING_DEF */
+  if (flag_whole_program)
+    {
+      if (prevailing->resolution == LDPR_PREVAILING_DEF)
+        {
+          if (TREE_CODE (prevailing->decl) == FUNCTION_DECL)
+            prevailing->node->local.used_from_object_file = true;
+          else
+            prevailing->vnode->used_from_object_file = true;
+        }
+      else if (prevailing->resolution == LDPR_PREVAILING_DEF_IRONLY)
+        {
+          if (TREE_CODE (prevailing->decl) == FUNCTION_DECL)
+            prevailing->node->local.used_from_object_file = false;
+          else
+            prevailing->vnode->used_from_object_file = false;
+        }
+    }
   return 1;
 }