[RFC PATCH] Don't use ELF weak for entities with vague linkage when COMDAT groups are available

[Julian Brown]

Mark Mitchell wrote:
> Julian Brown wrote:
> 
>> Hi,
>>
>> This is a patch to disable ELF weak for entities with vague linkage 
>> when HAVE_GAS_COMDAT_GROUP is true. It was previously posted in two 
>> parts and applied, then reverted soon after for causing breakage:
> 
> 
>> If people would try this patch and run the testsuite on their 
>> machines, I'd be grateful. I'd appreciate it if you post information 
>> about failures which show up for you, with version numbers of binutils 
>> bits, so I can attempt to track down whatever broke before.
> 
> 
> You've been met with deafening silence, which is disappointing.
> 
> As a result, I'm going to approve the patch again.  After you check it 
> in, please watch carefully for failure reports.  If you're reporting a 
> failure with this patch, *please* include assembler and linker versions, 
> so that Julian has a shot at reproducing the problem.
> 
> (I am suspicious that there are systems out there that have an assembler 
> with COMDAT support, but a linker without, and that this is the cause of 
> the problem.  In that case, the fix will be to tweak the configure 
> script not to define HAVE_GAS_COMDAT in that case.  Or, at least, to 
> provide a --disable-comdat option.)
> 
> Julian, if problems appear, please do not revert the patch immediately. 
>  Instead, please immediately disable it on the affected target system by 
> temporarily adding the old definition of MAKE_DECL_ONE_ONLY to the 
> affected target system.  And keep track so that we can undo this hackery 
> once the problem is resolved.
> 
> If you get more reports of problems on more than two systems, then 
> dorevert your patch -- but put the new definition of MAKE_DECL_ONE_ONLY 
> in an appropriate config/arm header file, so that at least we have it 
> there, where it originated.
> 
> I realize that this is all a bit irregular, but this is a broadly useful 
>  patch, and it really *should* work.  I can't see how to get information 
> about what's going on without checking the patch, given your diligent 
> testing, and the lack of response to your request-for-testing.

OK, I'll apply with this ChangeLog:

gcc:
     * config/elfos.h (MAKE_DECL_ONE_ONLY): Redefined to stop DECL_WEAK
     from being used for symbols with vague linkage when
     HAVE_GAS_COMDAT_GROUP is true.

java:
     * decl.c (finish_method): Give methods once-only linkage.