llvm dev - Nov 2010 - [LLVMdev] problem with __thread on linux/x86_64

On 11 November 2010 12:49, Jay Foad <jay.foad at gmail.com>
wrote:
> Delving a bit deeper, the difference seems to be that symbol "i"
in
> the assembler source:
>
>        .type   i, at object               # @i
>        .section        .tdata,"awT", at progbits
>        .globl  i
>        .align  4
> i:
>        .long   7                       # 0x7
>        .size   i, 4
>
> ... is given ELF symbol type STT_TLS by gcc's assembler, but
> STT_OBJECT by clang's assembler.
The .type directive should probably specify type "tls_object" rather
than just "object". But I think gas infers that this is a TLS symbol
anyway, because it is mentioned in TLS-related relocations. See this
thread and follow-ups:

http://www.cygwin.com/ml/binutils/2002-11/msg00409.html

Jay.

On 11 November 2010 13:22, Jay Foad <jay.foad at gmail.com>
wrote:
> On 11 November 2010 12:49, Jay Foad <jay.foad at gmail.com> wrote:
>> Delving a bit deeper, the difference seems to be that symbol
"i" in
>> the assembler source:
>>
>>        .type   i, at object               # @i
>>        .section        .tdata,"awT", at progbits
>>        .globl  i
>>        .align  4
>> i:
>>        .long   7                       # 0x7
>>        .size   i, 4
>>
>> ... is given ELF symbol type STT_TLS by gcc's assembler, but
>> STT_OBJECT by clang's assembler.
>
> The .type directive should probably specify type "tls_object"
rather
> than just "object".
The attached patch fixes this, and it makes my favourite (proprietary)
app work on Linux when compiled with clang.
> But I think gas infers that this is a TLS symbol
> anyway, because it is mentioned in TLS-related relocations.
I still think clang's assembler needs to do something like this, if it
wants to be able to assembler .s files generated by GCC.

Jay.
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> I still think clang's assembler needs to do something like this, if it
> wants to be able to assembler .s files generated by GCC.
Working on it.
> Jay.
Cheers,
Rafael