Add ELFOSABI_FIRST_ARCH, ELFOSABI_LAST_ARCH and start using those in llvm-readobj

[kzhuravl]

Summary

ELFOSABI value range 64-255 is architecture-specific.

[kzhuravl]

Rebase on top of trunk

[t-tye]

include/llvm/BinaryFormat/ELF.h

337–338

Suggest group by architecture.

338

// First architecture-specific OS ABI

339

// Last architecture-specific OS ABI

tools/llvm-readobj/ELFDumper.cpp

3527

Should the range checking also apply to the other architecture cases:

ELFOSABI_C6000_ELFABI = 64, // Bare-metal TMS320C6000
ELFOSABI_C6000_LINUX = 65,  // Linux TMS320C6000
ELFOSABI_ARM = 97,          // ARM

Not sure where ELFOSABI_STANDALONE belongs so maybe treat it as a non-architecture value even though it is in the range.

For example:

auto OSABI = makeArrayRef(ElfOSABI);
if (e->e_ident[ELF::EI_OSABI] >= ELF::ELFOSABI_FIRST_ARCH &&
    e->e_ident[ELF::EI_OSABI] <= ELF::ELFOSABI_LAST_ARCH) {
  switch (e->e_machine) {
  case ELF::EM_ARM:
    OSABI = makeArrayRef(ARMElfOSABI);
    break;
  case ELF::EM_TI_C6000:
    OSABI = makeArrayRef(C6000ElfOSABI);
    break;
  case ELF::EM_AMDGPU:
    OSABI = makeArrayRef(AMDGPUElfOSABI);
    break;
  }
}
W.printEnum("OS/ABI", e->e_ident[ELF::EI_OSABI], OSABI);

[kzhuravl]

Address review feedback.

[t-tye]

LGTM

include/llvm/BinaryFormat/ELF.h

 // Object file byte orderings.
 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_FIRST_ARCH = 64,    // First architecture-specific ABI
   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
+  ELFOSABI_STANDALONE = 255,   // Standalone (embedded) application
+  ELFOSABI_LAST_ARCH = 255     // Last Architecture-specific ABI
 };
 
 #define ELF_RELOC(name, value) name = value,
 
 // X86_64 relocations.
 enum {
 #include "ELFRelocs/x86_64.def"
 };

tools/llvm-readobj/ELFDumper.cpp

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