AMDGPU/SI: Set ELF OS/ABI to ELFOSABI_AMDGPU_HSA

[• rafael]

Please put the value in include/Support/ELF.h and fix llvm-readobj to
know the value is architecture dependent.

Cheers,
Rafael

[• tstellarAMD]

Updated patch. Added ELFOSABI_AMDGPU_HSA to ELF.h and added
support to llvm-readobj for printing it.

[• rafael]

LGTM

include/llvm/Support/ELF.h

enum {
   ELFOSABI_MODESTO = 11,      // Novell Modesto
   ELFOSABI_OPENBSD = 12,      // OpenBSD
   ELFOSABI_OPENVMS = 13,      // OpenVMS
   ELFOSABI_NSK = 14,          // Hewlett-Packard Non-Stop Kernel
   ELFOSABI_AROS = 15,         // AROS
   ELFOSABI_FENIXOS = 16,      // FenixOS
   ELFOSABI_CLOUDABI = 17,     // Nuxi CloudABI
   ELFOSABI_C6000_ELFABI = 64, // Bare-metal TMS320C6000
+  ELFOSABI_AMDGPU_HSA = 64,   // AMD HSA runtime
   ELFOSABI_C6000_LINUX = 65,  // Linux TMS320C6000
   ELFOSABI_ARM = 97,          // ARM
   ELFOSABI_STANDALONE = 255   // Standalone (embedded) application
 };
 
 #define ELF_RELOC(name, value) name = value,
 
 // X86_64 relocations.

lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp

protected:
   }
 
 };
 
 
 } // End anonymous namespace
 
 AMDGPUELFObjectWriter::AMDGPUELFObjectWriter(bool Is64Bit)
-  : MCELFObjectTargetWriter(Is64Bit, 0, ELF::EM_AMDGPU, false) { }
+  : MCELFObjectTargetWriter(Is64Bit, ELF::ELFOSABI_AMDGPU_HSA,
+                            ELF::EM_AMDGPU, false) { }
 
 MCObjectWriter *llvm::createAMDGPUELFObjectWriter(bool Is64Bit, raw_pwrite_stream &OS) {
   MCELFObjectTargetWriter *MOTW = new AMDGPUELFObjectWriter(Is64Bit);
   return createELFObjectWriter(MOTW, OS, true);
 }

test/CodeGen/AMDGPU/elf.ll

 ; RUN: llc < %s -march=amdgcn -mcpu=SI -verify-machineinstrs -filetype=obj | llvm-readobj -s -symbols -file-headers - | FileCheck --check-prefix=ELF %s
 ; RUN: llc < %s -march=amdgcn -mcpu=SI -verify-machineinstrs -o - | FileCheck --check-prefix=CONFIG --check-prefix=TYPICAL %s
 ; RUN: llc < %s -march=amdgcn -mcpu=tonga -verify-machineinstrs -filetype=obj | llvm-readobj -s -symbols -file-headers - | FileCheck --check-prefix=ELF %s
 ; RUN: llc < %s -march=amdgcn -mcpu=tonga -verify-machineinstrs -o - | FileCheck --check-prefix=CONFIG --check-prefix=TONGA %s
 ; RUN: llc < %s -march=amdgcn -mcpu=carrizo -verify-machineinstrs -filetype=obj | llvm-readobj -s -symbols -file-headers - | FileCheck --check-prefix=ELF %s
 ; RUN: llc < %s -march=amdgcn -mcpu=carrizo -verify-machineinstrs -o - | FileCheck --check-prefix=CONFIG --check-prefix=TYPICAL %s
 
 ; Test that we don't try to produce a COFF file on windows
 ; RUN: llc < %s -mtriple=amdgcn-pc-mingw -mcpu=SI -verify-machineinstrs -filetype=obj | llvm-readobj -s -symbols -file-headers - | FileCheck --check-prefix=ELF %s
 
 ; ELF: Format: ELF64
+; ELF: OS/ABI: AMDGPU_HSA (0x40)
 ; ELF: Machine: EM_AMDGPU (0xE0)
 ; ELF: Name: .AMDGPU.config
 ; ELF: Type: SHT_PROGBITS
 
 ; ELF: Symbol {
 ; ELF: Name: test
 ; ELF: Binding: Global
 

tools/llvm-readobj/ELFDumper.cpp

DictScope D(W, "ElfHeader");
       DictScope D(W, "Ident");
       W.printBinary("Magic", makeArrayRef(Header->e_ident).slice(ELF::EI_MAG0,
                                                                  4));
       W.printEnum  ("Class", Header->e_ident[ELF::EI_CLASS],
                       makeArrayRef(ElfClass));
       W.printEnum  ("DataEncoding", Header->e_ident[ELF::EI_DATA],
                       makeArrayRef(ElfDataEncoding));
       W.printNumber("FileVersion", Header->e_ident[ELF::EI_VERSION]);
+
+      // Handle architecture specific OS/ABI values.
+      if (Header->e_machine == ELF::EM_AMDGPU &&
+          Header->e_ident[ELF::EI_OSABI] == ELF::ELFOSABI_AMDGPU_HSA)
+        W.printHex("OS/ABI", "AMDGPU_HSA", ELF::ELFOSABI_AMDGPU_HSA);
+      else
         W.printEnum  ("OS/ABI", Header->e_ident[ELF::EI_OSABI],
                       makeArrayRef(ElfOSABI));
       W.printNumber("ABIVersion", Header->e_ident[ELF::EI_ABIVERSION]);
       W.printBinary("Unused", makeArrayRef(Header->e_ident).slice(ELF::EI_PAD));
     }
 
     W.printEnum  ("Type", Header->e_type, makeArrayRef(ElfObjectFileType));
     W.printEnum  ("Machine", Header->e_machine, makeArrayRef(ElfMachineType));
     W.printNumber("Version", Header->e_version);