[llvm-readelf] - Simplify the implementation of getSectionTypeString() helper. NFCI.

[grimar]

Summary

It is used for printing section headers in the GNU style
and the implementation can be simplified.

[jhenderson]

LGTM.

llvm/tools/llvm-readobj/ELFDumper.cpp

3760–3763

FWIW, I think this clause is a bad design in the original version - a user when dumping the section headers will not be able to distinguish between SHT_RELR and SHT_ANDROID_RELR. They might be identical internally, but the sh_type value is different.

We shouldn't fix it in this patch, but it might be worth reaching out to the original people to implement it to bring this up. What do you think?

[grimar]

llvm/tools/llvm-readobj/ELFDumper.cpp

3760–3763

Yeah. The fresh GNU source code (2.34) still doesn't know about SHT_ANDROID_RELR/SHT_RELR,
so seems it should not be a problem to fix it on LLVM side. I`ll prepare a patch.

llvm/tools/llvm-readobj/ELFDumper.cpp

if (Type >= SHT_LOOS && Type <= SHT_HIOS)
     return "LOOS+0x" + to_hexString(Type - SHT_LOOS);
   else if (Type >= SHT_LOPROC && Type <= SHT_HIPROC)
     return "LOPROC+0x" + to_hexString(Type - SHT_LOPROC);
   else if (Type >= SHT_LOUSER && Type <= SHT_HIUSER)
     return "LOUSER+0x" + to_hexString(Type - SHT_LOUSER);
   return "0x" + to_hexString(Type) + ": <unknown>";
 }
 
-static std::string getSectionTypeString(unsigned Arch, unsigned Type) {
-  using namespace ELF;
+static std::string getSectionTypeString(unsigned Machine, unsigned Type) {
+  StringRef Name = getELFSectionTypeName(Machine, Type);
 
-  switch (Arch) {
-  case EM_ARM:
-    switch (Type) {
-    case SHT_ARM_EXIDX:
-      return "ARM_EXIDX";
-    case SHT_ARM_PREEMPTMAP:
-      return "ARM_PREEMPTMAP";
-    case SHT_ARM_ATTRIBUTES:
-      return "ARM_ATTRIBUTES";
-    case SHT_ARM_DEBUGOVERLAY:
-      return "ARM_DEBUGOVERLAY";
-    case SHT_ARM_OVERLAYSECTION:
-      return "ARM_OVERLAYSECTION";
-    }
-    break;
-  case EM_X86_64:
-    switch (Type) {
-    case SHT_X86_64_UNWIND:
-      return "X86_64_UNWIND";
-    }
-    break;
-  case EM_MIPS:
-  case EM_MIPS_RS3_LE:
-    switch (Type) {
-    case SHT_MIPS_REGINFO:
-      return "MIPS_REGINFO";
-    case SHT_MIPS_OPTIONS:
-      return "MIPS_OPTIONS";
-    case SHT_MIPS_DWARF:
-      return "MIPS_DWARF";
-    case SHT_MIPS_ABIFLAGS:
-      return "MIPS_ABIFLAGS";
-    }
-    break;
-  case EM_RISCV:
-    switch (Type) {
-    case SHT_RISCV_ATTRIBUTES:
-      return "RISCV_ATTRIBUTES";
-    }
+  // Handle SHT_GNU_* type names.
+  if (Name.startswith("SHT_GNU_")) {
+    if (Name == "SHT_GNU_HASH")
+      return "GNU_HASH";
+    // E.g. SHT_GNU_verneed -> VERNEED.
+    return Name.drop_front(8).upper();
   }
-  switch (Type) {
-  case SHT_NULL:
-    return "NULL";
-  case SHT_PROGBITS:
-    return "PROGBITS";
-  case SHT_SYMTAB:
-    return "SYMTAB";
-  case SHT_STRTAB:
-    return "STRTAB";
-  case SHT_RELA:
-    return "RELA";
-  case SHT_HASH:
-    return "HASH";
-  case SHT_DYNAMIC:
-    return "DYNAMIC";
-  case SHT_NOTE:
-    return "NOTE";
-  case SHT_NOBITS:
-    return "NOBITS";
-  case SHT_REL:
-    return "REL";
-  case SHT_SHLIB:
-    return "SHLIB";
-  case SHT_DYNSYM:
-    return "DYNSYM";
-  case SHT_INIT_ARRAY:
-    return "INIT_ARRAY";
-  case SHT_FINI_ARRAY:
-    return "FINI_ARRAY";
-  case SHT_PREINIT_ARRAY:
-    return "PREINIT_ARRAY";
-  case SHT_GROUP:
-    return "GROUP";
-  case SHT_SYMTAB_SHNDX:
+
+  if (Name == "SHT_SYMTAB_SHNDX")
     return "SYMTAB SECTION INDICES";
-  case SHT_ANDROID_REL:
-    return "ANDROID_REL";
-  case SHT_ANDROID_RELA:
-    return "ANDROID_RELA";
-  case SHT_RELR:
-  case SHT_ANDROID_RELR:
+
+  // The SHT_ANDROID_RELR is special, all other SHT_ANDROID_* types are handled
+  // in the common block below.
+  if (Name == "SHT_ANDROID_RELR")
     return "RELR";
-  case SHT_LLVM_ODRTAB:
-    return "LLVM_ODRTAB";
-  case SHT_LLVM_LINKER_OPTIONS:
-    return "LLVM_LINKER_OPTIONS";
-  case SHT_LLVM_CALL_GRAPH_PROFILE:
-    return "LLVM_CALL_GRAPH_PROFILE";
-  case SHT_LLVM_ADDRSIG:
-    return "LLVM_ADDRSIG";
-  case SHT_LLVM_DEPENDENT_LIBRARIES:
-    return "LLVM_DEPENDENT_LIBRARIES";
-  case SHT_LLVM_SYMPART:
-    return "LLVM_SYMPART";
-  case SHT_LLVM_PART_EHDR:
-    return "LLVM_PART_EHDR";
-  case SHT_LLVM_PART_PHDR:
-    return "LLVM_PART_PHDR";
-  // FIXME: Parse processor specific GNU attributes
-  case SHT_GNU_ATTRIBUTES:
-    return "ATTRIBUTES";
-  case SHT_GNU_HASH:
-    return "GNU_HASH";
-  case SHT_GNU_verdef:
-    return "VERDEF";
-  case SHT_GNU_verneed:
-    return "VERNEED";
-  case SHT_GNU_versym:
-    return "VERSYM";
-  default:
-    return getSectionTypeOffsetString(Type);
-  }
-  return "";
-}
+
+  if (Name.startswith("SHT_"))
+    return Name.drop_front(4).str();
 
 static void printSectionDescription(formatted_raw_ostream &OS,
                                     unsigned EMachine) {
   OS << "Key to Flags:\n";
   OS << "  W (write), A (alloc), X (execute), M (merge), S (strings), I "
         "(info),\n";
   OS << "  L (link order), O (extra OS processing required), G (group), T "
         "(TLS),\n";