AMDGPU: Add ELFOSABI_AMDGPU_MESA3D

[t-tye]

docs/AMDGPUUsage.rst

404

One of the following AMD GPU architecture specific OS ABIs:

412–413

Is it necessary to mention "for AMD GCN GPUs (GFX6+)" as the other ones above do not, and presumably it would be ok for the R600 architecture to use this ABI too if it wanted to?

425–426

Same comment as above.

include/llvm/Object/ELFObjectFile.h

1071–1076

Same comment as in other patch.

[kzhuravl]

Address review feedback.

[t-tye]

LGTM

[kzhuravl]

Rebase.

[t-tye]

LGTM (couple minor documentation suggestions)

docs/AMDGPUUsage.rst

367

or -> ,

370

or -> ,

docs/AMDGPUUsage.rst

The AMDGPU backend uses the following ELF header:
   .. table:: AMDGPU ELF Header
      :name: amdgpu-elf-header-table
 
      ========================== ===============================
      Field                      Value
      ========================== ===============================
      ``e_ident[EI_CLASS]``      ``ELFCLASS64``
      ``e_ident[EI_DATA]``       ``ELFDATA2LSB``
      ``e_ident[EI_OSABI]``      ``ELFOSABI_AMDGPU_HSA`` or
-                                ``ELFOSABI_AMDGPU_PAL``
+                                ``ELFOSABI_AMDGPU_PAL`` or
+                                ``ELFOSABI_AMDGPU_MESA3D``
      ``e_ident[EI_ABIVERSION]`` ``ELFABIVERSION_AMDGPU_HSA`` or
-                                ``ELFABIVERSION_AMDGPU_PAL``
+                                ``ELFABIVERSION_AMDGPU_PAL`` or
+                                ``ELFABIVERSION_AMDGPU_MESA3D``
      ``e_type``                 ``ET_REL`` or ``ET_DYN``
      ``e_machine``              ``EM_AMDGPU``
      ``e_entry``                0
      ``e_flags``                0
      ========================== ===============================
 
 ..
 
   .. table:: AMDGPU ELF Header Enumeration Values
      :name: amdgpu-elf-header-enumeration-values-table
 
-     ============================ =====
-     Name                         Value
-     ============================ =====
-     ``EM_AMDGPU``                224
-     ``ELFOSABI_AMDGPU_HSA``      64
-     ``ELFOSABI_AMDGPU_PAL``      65
-     ``ELFABIVERSION_AMDGPU_HSA`` 1
-     ``ELFABIVERSION_AMDGPU_PAL`` 0
-     ============================ =====
+     =============================== =====
+     Name                            Value
+     =============================== =====
+     ``EM_AMDGPU``                   224
+     ``ELFOSABI_AMDGPU_HSA``         64
+     ``ELFOSABI_AMDGPU_PAL``         65
+     ``ELFOSABI_AMDGPU_MESA3D``      66
+     ``ELFABIVERSION_AMDGPU_HSA``    1
+     ``ELFABIVERSION_AMDGPU_PAL``    0
+     ``ELFABIVERSION_AMDGPU_MESA3D`` 0
+     =============================== =====
 
 ``e_ident[EI_CLASS]``
   The ELF class is always ``ELFCLASS64``. The AMDGPU backend only supports 64
   bit applications.
 
 ``e_ident[EI_DATA]``
   All AMDGPU targets use ELFDATA2LSB for little-endian byte ordering.
 
 ``e_ident[EI_OSABI]``
   One of two AMD GPU architecture specific OS ABI:
 
   * ``ELFOSABI_AMDGPU_HSA`` is used to specify that the code object conforms to
     the AMD HSA runtime ABI [HSA]_.
 
   * ``ELFOSABI_AMDGPU_PAL`` is used to specify that the code object conforms to
     the AMD PAL runtime ABI.
 
+  * ``ELFOSABI_AMDGPU_MESA3D`` is used to specify that the code object conforms
+    to the AMD MESA runtime ABI for AMD GCN GPUs (GFX6+).
+
 ``e_ident[EI_ABIVERSION]``
   The ABI version of the AMD GPU architecture specific OS ABI to which the code
   object conforms:
 
   * ``ELFABIVERSION_AMDGPU_HSA`` is used to specify the version of AMD HSA
     runtime ABI.
 
   * ``ELFABIVERSION_AMDGPU_PAL`` is used to specify the version of AMD PAL
     runtime ABI.
 
+  * ``ELFABIVERSION_AMDGPU_MESA3D`` is used to specify the version of AMD MESA
+    runtime ABI for AMD GCN GPUs (GFX6+).
+
 ``e_type``
   Can be one of the following values:
 
 
   ``ET_REL``
     The type produced by the AMD GPU backend compiler as it is relocatable code
     object.
 

include/llvm/BinaryFormat/ELF.h

 enum {
   ELFDATANONE = 0, // Invalid data encoding.
   ELFDATA2LSB = 1, // Little-endian object file
   ELFDATA2MSB = 2  // Big-endian object file
 };
 
 // OS ABI identification.
 enum {
-  ELFOSABI_NONE = 0,          // UNIX System V ABI
-  ELFOSABI_HPUX = 1,          // HP-UX operating system
-  ELFOSABI_NETBSD = 2,        // NetBSD
-  ELFOSABI_GNU = 3,           // GNU/Linux
-  ELFOSABI_LINUX = 3,         // Historical alias for ELFOSABI_GNU.
-  ELFOSABI_HURD = 4,          // GNU/Hurd
-  ELFOSABI_SOLARIS = 6,       // Solaris
-  ELFOSABI_AIX = 7,           // AIX
-  ELFOSABI_IRIX = 8,          // IRIX
-  ELFOSABI_FREEBSD = 9,       // FreeBSD
-  ELFOSABI_TRU64 = 10,        // TRU64 UNIX
-  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_C6000_LINUX = 65,  // Linux TMS320C6000
-  ELFOSABI_AMDGPU_HSA = 64,   // AMD HSA runtime
-  ELFOSABI_AMDGPU_PAL = 65,   // AMD PAL runtime
-  ELFOSABI_ARM = 97,          // ARM
-  ELFOSABI_STANDALONE = 255   // Standalone (embedded) application
+  ELFOSABI_NONE = 0,           // UNIX System V ABI
+  ELFOSABI_HPUX = 1,           // HP-UX operating system
+  ELFOSABI_NETBSD = 2,         // NetBSD
+  ELFOSABI_GNU = 3,            // GNU/Linux
+  ELFOSABI_LINUX = 3,          // Historical alias for ELFOSABI_GNU.
+  ELFOSABI_HURD = 4,           // GNU/Hurd
+  ELFOSABI_SOLARIS = 6,        // Solaris
+  ELFOSABI_AIX = 7,            // AIX
+  ELFOSABI_IRIX = 8,           // IRIX
+  ELFOSABI_FREEBSD = 9,        // FreeBSD
+  ELFOSABI_TRU64 = 10,         // TRU64 UNIX
+  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_C6000_LINUX = 65,   // Linux TMS320C6000
+  ELFOSABI_AMDGPU_HSA = 64,    // AMD HSA runtime
+  ELFOSABI_AMDGPU_PAL = 65,    // AMD PAL runtime
+  ELFOSABI_AMDGPU_MESA3D = 66, // AMD GCN GPUs (GFX6+) for MESA runtime
+  ELFOSABI_ARM = 97,           // ARM
+  ELFOSABI_STANDALONE = 255    // Standalone (embedded) application
 };
 
 #define ELF_RELOC(name, value) name = value,
 
 // X86_64 relocations.
 enum {
 #include "ELFRelocs/x86_64.def"
 };

include/llvm/Object/ELFObjectFile.h

case ELF::EM_WEBASSEMBLY:
     default: return Triple::UnknownArch;
     }
 
   case ELF::EM_AMDGPU:
     switch (EF.getHeader()->e_ident[ELF::EI_CLASS]) {
     case ELF::ELFCLASS32:
       return Triple::UnknownArch;
     case ELF::ELFCLASS64:
       switch (EF.getHeader()->e_ident[ELF::EI_OSABI]) {
       case ELF::ELFOSABI_AMDGPU_HSA:
       case ELF::ELFOSABI_AMDGPU_PAL:
+      case ELF::ELFOSABI_AMDGPU_MESA3D:
         return Triple::amdgcn;
       }
     }
 
   case ELF::EM_BPF:
     return IsLittleEndian ? Triple::bpfel : Triple::bpfeb;
 
   default:
     return Triple::UnknownArch;
   }

lib/ObjectYAML/ELFYAML.cpp

#define ECase(X) IO.enumCase(Value, #X, ELF::X)
   ECase(ELFOSABI_NSK);
   ECase(ELFOSABI_AROS);
   ECase(ELFOSABI_FENIXOS);
   ECase(ELFOSABI_CLOUDABI);
   ECase(ELFOSABI_C6000_ELFABI);
   ECase(ELFOSABI_C6000_LINUX);
   ECase(ELFOSABI_AMDGPU_HSA);
   ECase(ELFOSABI_AMDGPU_PAL);
+  ECase(ELFOSABI_AMDGPU_MESA3D);
   ECase(ELFOSABI_ARM);
   ECase(ELFOSABI_STANDALONE);
 #undef ECase
 }
 
 void ScalarBitSetTraits<ELFYAML::ELF_EF>::bitset(IO &IO,
                                                  ELFYAML::ELF_EF &Value) {
   const auto *Object = static_cast<ELFYAML::Object *>(IO.getContext());

test/Object/AMDGPU/elf64-amdgcn-mesa3d-definitions.yaml

+# RUN: yaml2obj %s > %t.o
+# RUN: llvm-readobj -s -file-headers %t.o | FileCheck %s
+
+# CHECK: Format: ELF64-amdgpu
+# CHECK: Arch: amdgcn
+# CHECK: ElfHeader {
+# CHECK:   Ident {
+# CHECK:     OS/ABI: MESA3D (0x42)
+# CHECK:     ABIVersion: 0
+# CHECK:   }
+# CHECK:   Machine: EM_AMDGPU (0xE0)
+# CHECK: }
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_REL
+  Machine: EM_AMDGPU
+  OSABI:   ELFOSABI_AMDGPU_MESA3D
+...

tools/llvm-readobj/ELFDumper.cpp

static const EnumEntry<unsigned> ElfOSABI[] = {
   {"CloudABI",     "CloudABI",             ELF::ELFOSABI_CLOUDABI},
   {"C6000_ELFABI", "Bare-metal C6000",     ELF::ELFOSABI_C6000_ELFABI},
   {"C6000_LINUX",  "Linux C6000",          ELF::ELFOSABI_C6000_LINUX},
   {"ARM",          "ARM",                  ELF::ELFOSABI_ARM},
   {"Standalone",   "Standalone App",       ELF::ELFOSABI_STANDALONE}
 };
 
 static const EnumEntry<unsigned> AMDGPUElfOSABI[] = {
-  {"AMDHSA", "AMDGPU - HSA", ELF::ELFOSABI_AMDGPU_HSA},
-  {"AMDPAL", "AMDGPU - PAL", ELF::ELFOSABI_AMDGPU_PAL}
+  {"AMDHSA", "AMDGPU - HSA",    ELF::ELFOSABI_AMDGPU_HSA},
+  {"AMDPAL", "AMDGPU - PAL",    ELF::ELFOSABI_AMDGPU_PAL},
+  {"MESA3D", "AMDGPU - MESA3D", ELF::ELFOSABI_AMDGPU_MESA3D}
 };
 
 static const EnumEntry<unsigned> ElfMachineType[] = {
   ENUM_ENT(EM_NONE,          "None"),
   ENUM_ENT(EM_M32,           "WE32100"),
   ENUM_ENT(EM_SPARC,         "Sparc"),
   ENUM_ENT(EM_386,           "Intel 80386"),
   ENUM_ENT(EM_68K,           "MC68000"),