ELF: Remove non-standard ELF features from AMDGPU target

[• rafael]

LGTM with nits.

Thanks a lot!

test/ELF/amdgpu-globals.s

123

Please leave just

# CHECK: Value:

The test should at some point be changed to use CHECK-NEXT.

136

Don't you want to convert this to "CHECK: Type: PT_LOAD"?

test/ELF/amdgpu-kernels.s

53

leave the "CHECK: Value:"

[ruiu]

LGTM. Thank you for doing this!

[ruiu]

Are you going to submit this?

ELF/OutputSections.cpp

for (const std::pair<const Elf_Sym *, size_t> &P : File->KeptLocalSyms) {
       if (Sym->st_shndx == SHN_ABS) {
         ESym->st_shndx = SHN_ABS;
         VA = Sym->st_value;
       } else {
         InputSectionBase<ELFT> *Section = File->getSection(*Sym);
         const OutputSectionBase<ELFT> *OutSec = Section->OutSec;
         ESym->st_shndx = OutSec->SectionIndex;
         VA = Section->getOffset(*Sym);
-
-        // Symbol offsets for AMDGPU are the offsets in bytes of the
-        // symbols from the beginning of the section. There seems to be no
-        // reason for that deviation -- it's just that the definition of
-        // st_value field in AMDGPU's ELF is odd.
-        if (Config->EMachine != EM_AMDGPU)
-          VA += OutSec->getVA();
       }
       ESym->st_name = P.second;
       ESym->st_size = Sym->st_size;
       ESym->setBindingAndType(Sym->getBinding(), Sym->getType());
       ESym->st_value = VA;
       Buf += sizeof(*ESym);
     }
   }

ELF/Symbols.cpp

case DefinedRegularKind: {
     auto *D = cast<DefinedRegular<ELFT>>(this);
     InputSectionBase<ELFT> *SC = D->Section;
 
     // This is an absolute symbol.
     if (!SC)
       return D->Sym.st_value;
     assert(SC->Live);
 
-    // Symbol offsets for AMDGPU are the offsets in bytes of the symbols
-    // from the beginning of the section. Note that this part of AMDGPU's
-    // ELF spec is odd and not in line with the standard ELF.
-    if (Config->EMachine == EM_AMDGPU)
-      return SC->getOffset(D->Sym);
-
     if (D->Sym.getType() == STT_TLS)
       return SC->OutSec->getVA() + SC->getOffset(D->Sym) -
              Out<ELFT>::TlsPhdr->p_vaddr;
     return SC->OutSec->getVA() + SC->getOffset(D->Sym);
   }
   case DefinedCommonKind:
     return Out<ELFT>::Bss->getVA() + cast<DefinedCommon>(this)->OffsetInBss;
   case SharedKind: {

ELF/Writer.cpp

static uint32_t toPhdrFlags(uint64_t Flags) {
   uint32_t Ret = PF_R;
   if (Flags & SHF_WRITE)
     Ret |= PF_W;
   if (Flags & SHF_EXECINSTR)
     Ret |= PF_X;
   return Ret;
 }
 
-/// For AMDGPU we need to use custom segment kinds in order to specify which
-/// address space data should be loaded into.
-template <class ELFT>
-static uint32_t getAmdgpuPhdr(OutputSectionBase<ELFT> *Sec) {
-  uint32_t Flags = Sec->getFlags();
-  if (Flags & SHF_AMDGPU_HSA_CODE)
-    return PT_AMDGPU_HSA_LOAD_CODE_AGENT;
-  if ((Flags & SHF_AMDGPU_HSA_GLOBAL) && !(Flags & SHF_AMDGPU_HSA_AGENT))
-    return PT_AMDGPU_HSA_LOAD_GLOBAL_PROGRAM;
-  return PT_LOAD;
-}
-
 // Decide which program headers to create and which sections to include in each
 // one.
 template <class ELFT> void Writer<ELFT>::createPhdrs() {
   auto AddHdr = [this](unsigned Type, unsigned Flags) {
     return &*Phdrs.emplace(Phdrs.end(), Type, Flags);
   };
 
   auto AddSec = [](Phdr &Hdr, OutputSectionBase<ELFT> *Sec) {
if (Sec->getFlags() & SHF_TLS)
       AddSec(TlsHdr, Sec);
 
     if (!needsPtLoad<ELFT>(Sec))
       continue;
 
     // If flags changed then we want new load segment.
     uintX_t NewFlags = toPhdrFlags(Sec->getFlags());
     if (Flags != NewFlags) {
-      uint32_t LoadType = (Config->EMachine == EM_AMDGPU) ? getAmdgpuPhdr(Sec)
-                                                          : (uint32_t)PT_LOAD;
-      Load = AddHdr(LoadType, NewFlags);
+      Load = AddHdr(PT_LOAD, NewFlags);
       Flags = NewFlags;
     }
 
     AddSec(*Load, Sec);
 
     if (isRelroSection(Sec))
       AddSec(RelRo, Sec);
   }

test/ELF/amdgpu-globals.s

 # CHECK: SHF_EXECINSTR (0x4)
 # CHECK: SHF_WRITE (0x1)
 # CHECK: ]
 # CHECK: Address: [[HSATEXT_ADDR:[0-9xa-f]+]]
 # CHECK: }
 
 # CHECK: Symbol {
 # CHECK: Name: module_global_agent
-# CHECK: Value: 0x0
 # CHECK: Size: 4
 # CHECK: Binding: Local
 # CHECK: Section: .hsadata_global_agent
 # CHECK: }
 
 # CHECK: Symbol {
 # CHECK: Name: module_global_program
-# CHECK: Value: 0x0
 # CHECK: Size: 4
 # CHECK: Binding: Local
 # CHECK: Section: .hsadata_global_program
 # CHECK: }
 
 # CHECK: Symbol {
 # CHECK: Name: module_global_readonly
-# CHECK: Value: 0x0
 # CHECK: Size: 4
 # CHECK: Binding: Local
 # CHECK: Type: Object
 # CHECK: Section: .hsatext
 # CHECK: }
 
 # CHECK: Symbol {
 # CHECK: Name: program_global_agent
-# CHECK: Value: 0x4
 # CHECK: Size: 4
 # CHECK: Binding: Global
 # CHECK: Type: Object
 # CHECK: Section: .hsadata_global_agent
 # CHECK: }
 
 # CHECK: Symbol {
 # CHECK: Name: program_global_program
-# CHECK: Value: 0x4
 # CHECK: Size: 4
 # CHECK: Binding: Global
 # CHECK: Type: Object
 # CHECK: Section: .hsadata_global_program
 # CHECK: }
 
 # CHECK: Symbol {
 # CHECK: Name: program_global_readonly
-# CHECK: Value: 0x4
 # CHECK: Size: 4
 # CHECK: Binding: Global
 # CHECK: Type: Object
 # CHECK: Section: .hsatext
 # CHECK: }
 
 # CHECK: ProgramHeader {
-# CHECK: Type: PT_AMDGPU_HSA_LOAD_GLOBAL_PROGRAM
-# CHECK: VirtualAddress: [[HSADATA_GLOBAL_PROGRAM_ADDR]]
-# CHECK: }
-
-# CHECK: ProgramHeader {
-# CHECK: Type: PT_AMDGPU_HSA_LOAD_CODE_AGENT
-# CHECK: VirtualAddress: [[HSATEXT_ADDR]]
+# CHECK: Type: PT_LOAD
 # CHECK: }

test/ELF/amdgpu-kernels.s

 # CHECK: SHF_EXECINSTR (0x4)
 # CHECK: SHF_WRITE (0x1)
 # CHECK: ]
 # CHECK: Address: [[HSATEXT_ADDR:[0-9xa-f]+]]
 # CHECK: }
 
 # CHECK: Symbol {
 # CHECK: Name: kernel0
-# CHECK: Value: 0x0
 # CHECK: Size: 4
 # CHECK: Binding: Global
 # CHECK: Type: AMDGPU_HSA_KERNEL
 # CHECK: Section: .hsatext
 # CHECK: }
 
 # CHECK: Symbol {
 # CHECK: Name: kernel1
-# CHECK: Value: 0x100
 # CHECK: Size: 8
 # CHECK: Binding: Global
 # CHECK: Type: AMDGPU_HSA_KERNEL
 # CHECK: Section: .hsatext
 # CHECK: }
 
 # CHECK: ProgramHeader {
-# CHECK: Type: PT_AMDGPU_HSA_LOAD_CODE_AGENT
-# CHECK: VirtualAddress: [[HSATEXT_ADDR]]
+# CHECK: Type: PT_LOAD
 # CHECK: }