[Bug lto/45375] [meta-bug] Issues with building Mozilla with LTO

[hubicka at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45375



--- Comment #165 from Jan Hubicka <hubicka at gcc dot gnu.org> 2013-01-09 
15:16:26 UTC ---

OK, I tracked down the undefined reference to

error: /tmp/cc0oq4BG.ltrans1.ltrans.o: requires dynamic R_X86_64_PC32 reloc

against '_ZN12SkAnnotationC1ER23SkFlattenableReadBuffer' which may overflow at

runtime; recompile with -fPIC



it is caused by bug in Mozilla - it includes file defininig virtual function

that use  '_ZN12SkAnnotationC1ER23SkFlattenableReadBuffer' (in SkPaint) but it

never links with implementation.

Normally the function is optimized out.  It is not due to fact that we never

optimize out virtual functions prior inlining for devirtualization and in WPA

path we forget to remove these when done.



Fixed by the following patch

Index: ipa-inline.c

===================================================================

--- ipa-inline.c        (revision 194916)

+++ ipa-inline.c        (working copy)

@@ -1793,7 +1793,7 @@

     }



   inline_small_functions ();

-  symtab_remove_unreachable_nodes (true, dump_file);

+  symtab_remove_unreachable_nodes (false, dump_file);

   free (order);



   /* Inline functions with a property that after inlining into all callers the

Index: lto/lto.c

===================================================================

--- lto/lto.c   (revision 194916)

+++ lto/lto.c   (working copy)

@@ -3215,6 +3215,7 @@

   cgraph_state = CGRAPH_STATE_IPA_SSA;



   execute_ipa_pass_list (all_regular_ipa_passes);

+  symtab_remove_unreachable_nodes (false, dump_file);



   if (cgraph_dump_file)

     {

Index: cgraphclones.c

===================================================================

--- cgraphclones.c      (revision 194916)

+++ cgraphclones.c      (working copy)

@@ -184,6 +184,7 @@

   new_node->symbol.decl = decl;

   symtab_register_node ((symtab_node)new_node);

   new_node->origin = n->origin;

+  new_node->symbol.lto_file_data = n->symbol.lto_file_data;

   if (new_node->origin)

     {

       new_node->next_nested = new_node->origin->nested;