[llvm] r265881 - [MC] support TLSDESC and TLSCALL / GNU2 tls dialect

[Rafael Espíndola via llvm-commits]

I just noticed that MC and GAS disagree on what format to use for the call

MC:
ff 90 00 00 00 00       callq  *0x0(%rax)

Gas:
ff 10                   callq  *(%rax)

Looks like MC thinks there is an "actual" relocation that will write a value.

Cheers,
Rafael


On 9 April 2016 at 16:32, Davide Italiano via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: davide
> Date: Sat Apr  9 15:32:33 2016
> New Revision: 265881
>
> URL: http://llvm.org/viewvc/llvm-project?rev=265881&view=rev
> Log:
> [MC] support TLSDESC and TLSCALL / GNU2 tls dialect
>
> Differential Revision:  http://reviews.llvm.org/D18885
>
> Added:
>     llvm/trunk/test/MC/ELF/relocation-tls.s
> Modified:
>     llvm/trunk/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
>
> Modified: llvm/trunk/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp?rev=265881&r1=265880&r2=265881&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp (original)
> +++ llvm/trunk/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp Sat Apr  9 15:32:33 2016
> @@ -154,6 +154,10 @@ static unsigned getRelocType64(MCContext
>      case RT64_8:
>        llvm_unreachable("Unimplemented");
>      }
> +  case MCSymbolRefExpr::VK_TLSCALL:
> +    return ELF::R_X86_64_TLSDESC_CALL;
> +  case MCSymbolRefExpr::VK_TLSDESC:
> +    return ELF::R_X86_64_GOTPC32_TLSDESC;
>    case MCSymbolRefExpr::VK_TLSGD:
>      checkIs32(Ctx, Loc, Type);
>      return ELF::R_X86_64_TLSGD;
>
> Added: llvm/trunk/test/MC/ELF/relocation-tls.s
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/relocation-tls.s?rev=265881&view=auto
> ==============================================================================
> --- llvm/trunk/test/MC/ELF/relocation-tls.s (added)
> +++ llvm/trunk/test/MC/ELF/relocation-tls.s Sat Apr  9 15:32:33 2016
> @@ -0,0 +1,26 @@
> +// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -s -sr | FileCheck  %s
> +
> +// Test that we produce the correct relocation.
> +
> +        leaq    _ZL3ccc at TLSDESC(%rip), %rax
> +        call    *_ZL3ccc at TLSCALL(%rax)
> +        addq    %fs:0, %rax
> +
> +// CHECK: Section {
> +// CHECK:   Index:
> +// CHECK:   Name: .rela.text
> +// CHECK-NEXT:   Type: SHT_RELA
> +// CHECK-NEXT:   Flags [
> +// CHECK-NEXT:   ]
> +// CHECK-NEXT:   Address: 0x0
> +// CHECK-NEXT:   Offset:
> +// CHECK-NEXT:   Size:
> +// CHECK-NEXT:   Link:
> +// CHECK-NEXT:   Info:
> +// CHECK-NEXT:   AddressAlignment: 8
> +// CHECK-NEXT:   EntrySize: 24
> +// CHECK-NEXT:   Relocations [
> +// CHECK-NEXT:     0x3 R_X86_64_GOTPC32_TLSDESC _ZL3ccc 0xFFFFFFFFFFFFFFFC
> +// CHECK-NEXT:     0x9 R_X86_64_TLSDESC_CALL _ZL3ccc 0x0
> +// CHECK-NEXT:   ]
> +// CHECK-NEXT: }
>
>
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