[yaml2obj/obj2yaml] - Support dumping/parsing ABI version.

[grimar]

Summary

These tools were assuming ABI version is 0,
that is not always true.

Patch teaches them to work with that field.

include/llvm/ObjectYAML/ELFYAML.h

 LLVM_YAML_STRONG_TYPEDEF(uint32_t, MIPS_ISA)
 
 // For now, hardcode 64 bits everywhere that 32 or 64 would be needed
 // since 64-bit can hold 32-bit values too.
 struct FileHeader {
   ELF_ELFCLASS Class;
   ELF_ELFDATA Data;
   ELF_ELFOSABI OSABI;
+  llvm::yaml::Hex8 ABIVersion;
   ELF_ET Type;
   ELF_EM Machine;
   ELF_EF Flags;
   llvm::yaml::Hex64 Entry;
 };
 
 struct SectionName {
   StringRef Section;

lib/ObjectYAML/ELFYAML.cpp

 #undef BCase
 }
 
 void MappingTraits<ELFYAML::FileHeader>::mapping(IO &IO,
                                                  ELFYAML::FileHeader &FileHdr) {
   IO.mapRequired("Class", FileHdr.Class);
   IO.mapRequired("Data", FileHdr.Data);
   IO.mapOptional("OSABI", FileHdr.OSABI, ELFYAML::ELF_ELFOSABI(0));
+  IO.mapOptional("ABIVersion", FileHdr.ABIVersion, Hex8(0));
   IO.mapRequired("Type", FileHdr.Type);
   IO.mapRequired("Machine", FileHdr.Machine);
   IO.mapOptional("Flags", FileHdr.Flags, ELFYAML::ELF_EF(0));
   IO.mapOptional("Entry", FileHdr.Entry, Hex64(0));
 }
 
 void MappingTraits<ELFYAML::ProgramHeader>::mapping(
     IO &IO, ELFYAML::ProgramHeader &Phdr) {

test/tools/yaml2obj/elf-abiversion.yaml

+# RUN: yaml2obj %s -o %t
+# RUN: llvm-readobj -file-headers %t | FileCheck %s --check-prefix=FROMYAML
+# RUN: obj2yaml %t | FileCheck %s --check-prefix=TOYAML
+
+## Check we are able to parse/emit the ABI version with yaml2obj/obj2yaml.
+
+# FROMYAML: ABIVersion: 5
+# TOYAML:   ABIVersion: 0x05
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_X86_64
+  ABIVersion:      0x05

tools/obj2yaml/elf2yaml.cpp

 
 template <class ELFT> ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
   auto Y = make_unique<ELFYAML::Object>();
 
   // Dump header
   Y->Header.Class = ELFYAML::ELF_ELFCLASS(Obj.getHeader()->getFileClass());
   Y->Header.Data = ELFYAML::ELF_ELFDATA(Obj.getHeader()->getDataEncoding());
   Y->Header.OSABI = Obj.getHeader()->e_ident[ELF::EI_OSABI];
+  Y->Header.ABIVersion = Obj.getHeader()->e_ident[ELF::EI_ABIVERSION];
   Y->Header.Type = Obj.getHeader()->e_type;
   Y->Header.Machine = Obj.getHeader()->e_machine;
   Y->Header.Flags = Obj.getHeader()->e_flags;
   Y->Header.Entry = Obj.getHeader()->e_entry;
 
   const Elf_Shdr *Symtab = nullptr;
   const Elf_Shdr *DynSymtab = nullptr;
 

tools/yaml2obj/yaml2elf.cpp

void ELFState<ELFT>::initELFHeader(Elf_Ehdr &Header) {
   Header.e_ident[EI_MAG1] = 'E';
   Header.e_ident[EI_MAG2] = 'L';
   Header.e_ident[EI_MAG3] = 'F';
   Header.e_ident[EI_CLASS] = ELFT::Is64Bits ? ELFCLASS64 : ELFCLASS32;
   bool IsLittleEndian = ELFT::TargetEndianness == support::little;
   Header.e_ident[EI_DATA] = IsLittleEndian ? ELFDATA2LSB : ELFDATA2MSB;
   Header.e_ident[EI_VERSION] = EV_CURRENT;
   Header.e_ident[EI_OSABI] = Doc.Header.OSABI;
-  Header.e_ident[EI_ABIVERSION] = 0;
+  Header.e_ident[EI_ABIVERSION] = Doc.Header.ABIVersion;
   Header.e_type = Doc.Header.Type;
   Header.e_machine = Doc.Header.Machine;
   Header.e_version = EV_CURRENT;
   Header.e_entry = Doc.Header.Entry;
   Header.e_phoff = sizeof(Header);
   Header.e_flags = Doc.Header.Flags;
   Header.e_ehsize = sizeof(Elf_Ehdr);
   Header.e_phentsize = sizeof(Elf_Phdr);