[PATCH] D21482: Support/ELF: Add R_AMDGPU_GOTPCREL relocation

[Rafael Espíndola via llvm-commits]

git-clang-format the patch.

Out of curiosity, why do you need a got? Are GPU fancy enough to have
shared libraries and symbol preemption these days?

Cheers,
Rafael


On 17 June 2016 at 17:31, Tom Stellard <thomas.stellard at amd.com> wrote:
> tstellarAMD created this revision.
> tstellarAMD added reviewers: arsenm, kzhuravl, rafael, ruiu, tony-tye.
> tstellarAMD added a subscriber: llvm-commits.
> Herald added subscribers: kzhuravl, arsenm.
>
> We will start generating this in a future patch.
>
> Change-Id: Id5fae1e8e6887ab7bbecbf445d1834a3aed4a5c9
>
> http://reviews.llvm.org/D21482
>
> Files:
>   docs/CodeGenerator.rst
>   include/llvm/Support/ELFRelocs/AMDGPU.def
>   lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp
>
> Index: lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp
> ===================================================================
> --- lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp
> +++ lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp
> @@ -38,6 +38,12 @@
>                                               const MCValue &Target,
>                                               const MCFixup &Fixup,
>                                               bool IsPCRel) const {
> +
> +  switch (Target.getAccessVariant()) {
> +  default: break;
> +  case MCSymbolRefExpr::VK_GOTPCREL: return ELF::R_AMDGPU_GOTPCREL;
> +  }
> +
>    switch (Fixup.getKind()) {
>    default: break;
>    case FK_Data_4:
> Index: include/llvm/Support/ELFRelocs/AMDGPU.def
> ===================================================================
> --- include/llvm/Support/ELFRelocs/AMDGPU.def
> +++ include/llvm/Support/ELFRelocs/AMDGPU.def
> @@ -9,3 +9,4 @@
>  ELF_RELOC(R_AMDGPU_REL32,         4)
>  ELF_RELOC(R_AMDGPU_REL64,         5)
>  ELF_RELOC(R_AMDGPU_ABS32,         6)
> +ELF_RELOC(R_AMDGPU_GOTPCREL,      7)
> Index: docs/CodeGenerator.rst
> ===================================================================
> --- docs/CodeGenerator.rst
> +++ docs/CodeGenerator.rst
> @@ -2676,6 +2676,9 @@
>
>  * **A** --- Represents the addend used to compute the value of the relocatable
>    field
> +* **G** --- Represents the offset into the global offset table at which the
> +  relocation entry’s symbol will reside during execution.
> +* **GOT** --- Represents the address of the global offset table.
>  * **P** --- Represents the place (section offset or address) of the storage unit
>    being relocated (computed using ``r_offset``)
>  * **S** --- Represents the value of the symbol whose index resides in the
> @@ -2694,4 +2697,5 @@
>    ``R_AMDGPU_REL32``     4      ``word32``  S + A - P
>    ``R_AMDGPU_REL64``     5      ``word64``  S + A - P
>    ``R_AMDGPU_ABS32``     6      ``word32``  S + A
> +  ``R_AMDGPU_GOTPCREL    7      ``word32``  G + GOT + A - P
>    =====================  =====  ==========  ====================
>
>