Re: Fix i386 wrong code issues introduced by the local flag fix

[Jan Hubicka]

Hi,
this patch fixes ICE when building firefox reported by Markus:
> 
> lto1: internal compiler error: Segmentation fault
> 0x106e1feb crash_signal
>         ../../gcc/gcc/toplev.c:383
> 0x10589cd4 lto_get_decl_name_mapping(lto_file_decl_data*, char const*)
>         ../../gcc/gcc/lto-section-in.c:369
> 0x1057bb6b copy_function_or_variable
>         ../../gcc/gcc/lto-streamer-out.c:2194
> 0x1057df9b lto_output()
>         ../../gcc/gcc/lto-streamer-out.c:2289
> 0x105edd87 write_lto
>         ../../gcc/gcc/passes.c:2405
> 0x105f3073 ipa_write_optimization_summaries(lto_symtab_encoder_d*)
>         ../../gcc/gcc/passes.c:2607
> 0x1018f6ab do_stream_out
>         ../../gcc/gcc/lto/lto.c:2480
> 0x10190a33 stream_out
>         ../../gcc/gcc/lto/lto.c:2544
> 0x10190a33 lto_wpa_write_files
>         ../../gcc/gcc/lto/lto.c:2661
> 0x1019c0a7 do_whole_program_analysis
>         ../../gcc/gcc/lto/lto.c:3331
> 0x1019c0a7 lto_main()
>         ../../gcc/gcc/lto/lto.c:3451
> 

I tested it on Firefox, will commit after bootstrap&regtesting finishes (x86_64)

Honza

        * ipa.c (symbol_table::remove_unreachable_nodes): Avoid releasing
        bodies of thunks; comment on why.
        * symtab.c (symtab_node::get_partitioning_class): Aliases of extern
        symbols are extern.
Index: ipa.c
===================================================================
--- ipa.c       (revision 220608)
+++ ipa.c       (working copy)
@@ -537,7 +537,13 @@ symbol_table::remove_unreachable_nodes (
       /* If node is unreachable, remove its body.  */
       else if (!reachable.contains (node))
         {
-         if (!body_needed_for_clonning.contains (node->decl))
+         /* We keep definitions of thunks and aliases in the boundary so
+            we can walk to the ultimate alias targets and function symbols
+            reliably.  */
+         if (node->alias || node->thunk.thunk_p)
+           ;
+         else if (!body_needed_for_clonning.contains (node->decl)
+             && !node->alias && !node->thunk.thunk_p)
            node->release_body ();
          else if (!node->clone_of)
            gcc_assert (in_lto_p || DECL_RESULT (node->decl));
Index: symtab.c
===================================================================
--- symtab.c    (revision 220608)
+++ symtab.c    (working copy)
@@ -1779,6 +1779,8 @@ symtab_node::get_partitioning_class (voi
 
   if (varpool_node *vnode = dyn_cast <varpool_node *> (this))
     {
+      if (alias && definition && !ultimate_alias_target ()->definition)
+       return SYMBOL_EXTERNAL;
       /* Constant pool references use local symbol names that can not
          be promoted global.  We should never put into a constant pool
          objects that can not be duplicated across partitions.  */
@@ -1790,7 +1792,7 @@ symtab_node::get_partitioning_class (voi
      Handle them as external; compute_ltrans_boundary take care to make
      proper things to happen (i.e. to make them appear in the boundary but
      with body streamed, so clone can me materialized).  */
-  else if (!dyn_cast <cgraph_node *> (this)->definition)
+  else if (!dyn_cast <cgraph_node *> (this)->function_symbol ()->definition)
     return SYMBOL_EXTERNAL;
 
   /* Linker discardable symbols are duplicated to every use unless they are