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Patch to fix a bug with version scripts and gc-sections in the GOLD linker.

Sriraman Tallam tmsriram@google.com
Sun Jul 24 14:23:00 GMT 2011 
Hi Ian,

   That change does not break any test case. I submitted it after changing it.

Thanks,
-Sri.

  2011-07-22  Sriraman Tallam  <tmsriram@google.com>

	* symtab.cc (Symbol_table::add_from_relobj): Mark symbol as referenced
	only after checking if it cannot be forced local.
	* symtab.h (is_externally_visible): Check if the symbol is not forced
	local.



Index: symtab.cc
===================================================================
RCS file: /cvs/src/src/gold/symtab.cc,v
retrieving revision 1.157
diff -u -u -p -r1.157 symtab.cc
--- symtab.cc	8 Jul 2011 23:49:11 -0000	1.157
+++ symtab.cc	22 Jul 2011 22:30:19 -0000
@@ -1238,15 +1238,15 @@ Symbol_table::add_from_relobj(
 				  is_default_version, *psym, st_shndx,
 				  is_ordinary, orig_st_shndx);

+      if (is_forced_local)
+	this->force_local(res);
+
       // If building a shared library using garbage collection, do not
       // treat externally visible symbols as garbage.
       if (parameters->options().gc_sections()
           && parameters->options().shared())
         this->gc_mark_symbol_for_shlib(res);

-      if (is_forced_local)
-	this->force_local(res);
-
       if (is_defined_in_discarded_section)
 	res->set_is_defined_in_discarded_section();

Index: symtab.h
===================================================================
RCS file: /cvs/src/src/gold/symtab.h,v
retrieving revision 1.124
diff -u -u -p -r1.124 symtab.h
--- symtab.h	8 Jul 2011 23:49:11 -0000	1.124
+++ symtab.h	22 Jul 2011 22:30:19 -0000
@@ -538,8 +538,9 @@ class Symbol
   bool
   is_externally_visible() const
   {
-    return (this->visibility_ == elfcpp::STV_DEFAULT
-            || this->visibility_ == elfcpp::STV_PROTECTED);
+    return ((this->visibility_ == elfcpp::STV_DEFAULT
+             || this->visibility_ == elfcpp::STV_PROTECTED)
+	    && !this->is_forced_local_);
   }
Thanks,
-Sri.

On Fri, Jul 22, 2011 at 3:09 PM, Ian Lance Taylor <iant@google.com> wrote:
> Sriraman Tallam <tmsriram@google.com> writes:
>
>> Function bar is not garbage collected even though it is local.
>>
>> This simple patch fixes it.
>>
>>       * symtab.cc (Symbol_table::gc_mark_symbol_for_shlib): Check if symbol
>>       is not forced local before marking it as referenced.
>>       (Symbol_table::add_from_relobj): Mark symbol as referenced only after
>>       checking if they cannot be forced local.
>
> I would like to suggest that you instead change
> Symbol::is_externally_visible to return false if this->is_forced_local()
> is true.  I think that will fix your problem, and I don't think think
> that will break anything--but, then, I haven't tried it.
>
> If that patch works, it is preapproved.
>
> Thanks.
>
> Ian
>
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