[yaml2obj] Rename SHOffset (e_shoff) field to SHOff. NFC

[MaskRay]

Summary

struct Elf*_Shdr has a field sh_offset, named ShOffset in
llvm::ELFYAML::Section. Rename SHOffset (e_shoff) to SHOff to prevent confusion.

[MaskRay]

Fix test/Object/invalid.test and a reference in a comment

[grimar]

LGTM

[grimar]

nit: I'd add "NFC" to title.

[MaskRay]

Add NFC to the title

[jhenderson]

Um... Why was this marked NFC? It changed one of the tags...

[grimar]

Oh indeed... I did not notice it changed the tag too. It is my fault, I asked for this.

include/llvm/ObjectYAML/ELFYAML.h

struct FileHeader {
   ELF_ELFOSABI OSABI;
   llvm::yaml::Hex8 ABIVersion;
   ELF_ET Type;
   ELF_EM Machine;
   ELF_EF Flags;
   llvm::yaml::Hex64 Entry;
 
   Optional<llvm::yaml::Hex16> SHEntSize;
-  Optional<llvm::yaml::Hex64> SHOffset;
+  Optional<llvm::yaml::Hex64> SHOff;
   Optional<llvm::yaml::Hex16> SHNum;
   Optional<llvm::yaml::Hex16> SHStrNdx;
 };
 
 struct SectionName {
   StringRef Section;
 };
 

lib/ObjectYAML/ELFEmitter.cpp

void ELFState<ELFT>::writeELFHeader(ContiguousBlobAccumulator &CBA, raw_ostream &OS) {
   Header.e_ehsize = sizeof(Elf_Ehdr);
   Header.e_phentsize = sizeof(Elf_Phdr);
   Header.e_phnum = Doc.ProgramHeaders.size();
 
   Header.e_shentsize =
       Doc.Header.SHEntSize ? (uint16_t)*Doc.Header.SHEntSize : sizeof(Elf_Shdr);
   // Immediately following the ELF header and program headers.
   // Align the start of the section header and write the ELF header.
-  uint64_t ShOffset;
-  CBA.getOSAndAlignedOffset(ShOffset, sizeof(typename ELFT::uint));
-  Header.e_shoff = Doc.Header.SHOffset
-                       ? typename ELFT::uint(*Doc.Header.SHOffset)
-                       : ShOffset;
+  uint64_t SHOff;
+  CBA.getOSAndAlignedOffset(SHOff, sizeof(typename ELFT::uint));
+  Header.e_shoff =
+      Doc.Header.SHOff ? typename ELFT::uint(*Doc.Header.SHOff) : SHOff;
   Header.e_shnum =
       Doc.Header.SHNum ? (uint16_t)*Doc.Header.SHNum : Doc.Sections.size();
   Header.e_shstrndx = Doc.Header.SHStrNdx ? (uint16_t)*Doc.Header.SHStrNdx
                                           : SN2I.get(".shstrtab");
 
   OS.write((const char *)&Header, sizeof(Header));
 }
 

lib/ObjectYAML/ELFYAML.cpp

void MappingTraits<ELFYAML::FileHeader>::mapping(IO &IO,
   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));
 
   IO.mapOptional("SHEntSize", FileHdr.SHEntSize);
-  IO.mapOptional("SHOffset", FileHdr.SHOffset);
+  IO.mapOptional("SHOff", FileHdr.SHOff);
   IO.mapOptional("SHNum", FileHdr.SHNum);
   IO.mapOptional("SHStrNdx", FileHdr.SHStrNdx);
 }
 
 void MappingTraits<ELFYAML::ProgramHeader>::mapping(
     IO &IO, ELFYAML::ProgramHeader &Phdr) {
   IO.mapRequired("Type", Phdr.Type);
   IO.mapOptional("Flags", Phdr.Flags, ELFYAML::ELF_PF(0));

test/Object/invalid.test

FileHeader:
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64
   SHNum:   0x0
 Sections:
   - Type: SHT_NULL
     Size: 288230376151711744
 
-## Check the case when SHOffset is too large. SHOffset + sizeof(Elf_Shdr) overflows the uint64 type.
+## Check the case when SHOff is too large. SHOff + sizeof(Elf_Shdr) overflows the uint64 type.
 
 # RUN: yaml2obj --docnum=28 %s -o %t28
 # RUN: not llvm-readobj -h %t28 2>&1 | FileCheck -DFILE=%t28 --check-prefix=INVALID-SEC-NUM3 %s
 
 # INVALID-SEC-NUM3: error: '[[FILE]]': section header table goes past the end of the file: e_shoff = 0xffffffffffffffff
  
 --- !ELF
 FileHeader:
   Class:    ELFCLASS64
   Data:     ELFDATA2LSB
   Type:     ET_REL
   Machine:  EM_X86_64
-  SHOffset: 0xffffffffffffffff
+  SHOff:    0xffffffffffffffff
 
 ## Check that llvm-objdump reports an error when it tries to dump a
 ## symbol name and .strtab is empty.
 
 # RUN: yaml2obj %s --docnum=29 -o %t29
 # RUN: not llvm-objdump -syms %t29 2>&1 | FileCheck -DFILE=%t29 --check-prefix=STRTAB-EMPTY2 %s
 
 # STRTAB-EMPTY2: error: '[[FILE]]': SHT_STRTAB string table section [index 1] is empty

test/tools/yaml2obj/elf-header-sh-fields.yaml

 
 --- !ELF
 FileHeader:
   Class:     ELFCLASS64
   Data:      ELFDATA2LSB
   Type:      ET_REL
   Machine:   EM_X86_64
   SHEntSize: 64
-  SHOffset:  2
+  SHOff:     2
   SHNum:     3
   SHStrNdx:  4
 
 ## Finally, we use the same YAML as above, but set e_shentsize to 1.
 ## Check the result using raw output from 'od' because llvm-readelf
 ## is unable to dump such headers.
 
 # RUN: yaml2obj --docnum=3 %s -o %t3
 # RUN: od -A n -t x1 -v -j 0x3a -N 1 %t3 | FileCheck %s --check-prefix=NEWSIZE
 # RUN: od -A n -t x1 -v -j 0x3a -N 1 %t2 | FileCheck %s --check-prefix=OLDSIZE
 # NEWSIZE: 01
 # OLDSIZE: 40
 
 --- !ELF
 FileHeader:
   Class:     ELFCLASS64
   Data:      ELFDATA2LSB
   Type:      ET_REL
   Machine:   EM_X86_64
   SHEntSize: 1
-  SHOffset:  2
+  SHOff:     2
   SHNum:     3
   SHStrNdx:  4

tools/obj2yaml/elf2yaml.cpp

ELFDumper<ELFT>::getUniquedSymbolName(const Elf_Sym *Sym, StringRef StrTable,
   }
 
   return Name;
 }
 
 template <class ELFT> Expected<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
   auto Y = std::make_unique<ELFYAML::Object>();
 
-  // Dump header. We do not dump SHEntSize, SHOffset, SHNum and SHStrNdx field.
+  // Dump header. We do not dump SHEntSize, SHOff, SHNum and SHStrNdx fields.
   // When not explicitly set, the values are set by yaml2obj automatically
   // and there is no need to dump them here.
   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;