[BFD][PR21703]Override the new defined symbol with the old normal symbol when --allow-multiple-definition is provided

[Renlin Li]

Hi Alan,

On 08/07/17 03:11, Alan Modra wrote:
> On Fri, Jul 07, 2017 at 05:41:04PM +0100, Renlin Li wrote:
>> diff --git a/bfd/elflink.c b/bfd/elflink.c
>> index 471e8ad..e4ab670 100644
>> --- a/bfd/elflink.c
>> +++ b/bfd/elflink.c
>> @@ -1547,6 +1547,17 @@ _bfd_elf_merge_symbol (bfd *abfd,
>>         sec = *psec;
>>       }
>>
>> +  /* There are multiple definitions of a normal symbol.  */
>> +  if (olddef && !olddyn && !oldweak && newdef && !newdyn && !newweak
>> +      && !*matched)
>
> I think !*matched is wrong, and will likely mean the patch doesn't fix
> your PR.
I meant to skip the case for versioned symbol. This function will be called with short 
name for versioned symbol. That's should be skipped.

I correct the condition and add one more condition for ld plugin case.
>
>> +    {
>> +      /* Handle a multiple definition.  */
>> +      (*info->callbacks->multiple_definition) (info, &h->root,
>> +					       abfd, sec, sym->st_value);
>
> Please use *pvalue here rather than sym->st_value.

Updated.
A new test case is added. The symbol foo in the final object should be of size 4 which 
comes from the first object file.


Here, the symbol types are not required to be the same. I think this is the desired behavior?

ld cross and native checked Okay for arm environment. glibc builds Okay with the patched 
linker.

Okay?

Regards,
Renlin

ld/ChangeLog:

2017-07-11  Renlin Li  <renlin.li@arm.com>

         PR ld/21703
	* testsuite/ld-elf/elf.exp : Run new test case.
	* testsuite/ld-elf/pr21703-1.s: New.
	* testsuite/ld-elf/pr21703-2.s: New.
	* testsuite/ld-elf/pr21703.sd: New.

bfd/ChangeLog:

2017-07-11  Renlin Li  <renlin.li@arm.com>

         PR ld/21703
	* elflink.c (_bfd_elf_merge_symbol): Handle multiple symbol definition
	case.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: tmp.diff
Type: text/x-patch
Size: 2403 bytes
Desc: not available
URL: <https://sourceware.org/pipermail/binutils/attachments/20170711/451140ee/attachment.bin>