[llvm-readelf] - Improve ELF type field dumping.

This is related to https://bugs.llvm.org/show_bug.cgi?id=40868.

Currently we don't print `OS Specific`/``Processor Specific`/`<unknown>`
prefixes when dumping the ELF file type. This is not consistent
with GNU readelf. The patch fixes it.

Also, this patch removes the `types.test`, because we already have
`file-types.test`, which tests more cases and this patch revealed that
we have such a duplicate.

Differential revision: https://reviews.llvm.org/D93096

Author: Georgii Rymar

llvm/include/llvm/BinaryFormat/ELF.h

@@ -107,13 +107,17 @@ struct Elf64_Ehdr {
   unsigned char getDataEncoding() const { return e_ident[EI_DATA]; }
 };
 
-// File types
+// File types.
+// See current registered ELF types at:
+//    http://www.sco.com/developers/gabi/latest/ch4.eheader.html
 enum {
   ET_NONE = 0,        // No file type
   ET_REL = 1,         // Relocatable file
   ET_EXEC = 2,        // Executable file
   ET_DYN = 3,         // Shared object file
   ET_CORE = 4,        // Core file
+  ET_LOOS = 0xfe00,   // Beginning of operating system-specific codes
+  ET_HIOS = 0xfeff,   // Operating system-specific
   ET_LOPROC = 0xff00, // Beginning of processor-specific codes
   ET_HIPROC = 0xffff  // Processor-specific
 };

llvm/test/tools/llvm-readobj/ELF/file-types.test

@@ -56,6 +56,17 @@ FileHeader:
 # GNU-CORE: ELF Header:
 # GNU-CORE:   Type: CORE (Core file)
 
+## Test what we dump for an arbitrary unknown ELF type.
+# RUN: yaml2obj %s -DTYPE=0xFDFF -o %t.unknown
+# RUN: llvm-readobj -h %t.unknown | FileCheck %s --match-full-lines --check-prefix LLVM-UNNKNOWN
+# RUN: llvm-readelf -h %t.unknown | FileCheck %s --match-full-lines --check-prefix GNU-UNNKNOWN
+
+# LLVM-UNNKNOWN: ElfHeader {
+# LLVM-UNNKNOWN:   Type: 0xFDFF
+
+# GNU-UNNKNOWN: ELF Header:
+# GNU-UNNKNOWN:   Type: <unknown>: fdff
+
 # RUN: yaml2obj %s -DTYPE=0xfe00 -o %t6
 # RUN: llvm-readobj -h %t6 | FileCheck %s --match-full-lines --check-prefix LLVM-LOOS
 # RUN: llvm-readelf -h %t6 | FileCheck %s --match-full-lines --check-prefix GNU-LOOS
@@ -64,7 +75,7 @@ FileHeader:
 # LLVM-LOOS:   Type: 0xFE00
 
 # GNU-LOOS: ELF Header:
-# GNU-LOOS:   Type: fe00
+# GNU-LOOS:   Type: OS Specific: (fe00)
 
 # RUN: yaml2obj %s -DTYPE=0xfeff -o %t7
 # RUN: llvm-readobj -h %t7 | FileCheck %s --match-full-lines --check-prefix LLVM-HIOS
@@ -74,7 +85,7 @@ FileHeader:
 # LLVM-HIOS:   Type: 0xFEFF
 
 # GNU-HIOS: ELF Header:
-# GNU-HIOS:   Type: feff
+# GNU-HIOS:   Type: OS Specific: (feff)
 
 # RUN: yaml2obj %s -DTYPE=0xff00 -o %t8
 # RUN: llvm-readobj -h %t8 | FileCheck %s --match-full-lines --check-prefix LLVM-LOPROC
@@ -84,7 +95,7 @@ FileHeader:
 # LLVM-LOPROC:   Type: 0xFF00
 
 # GNU-LOPROC: ELF Header:
-# GNU-LOPROC:   Type: ff00
+# GNU-LOPROC:   Type: Processor Specific: (ff00)
 
 # RUN: yaml2obj %s -DTYPE=0xffff -o %t9
 # RUN: llvm-readobj -h %t9 | FileCheck %s --match-full-lines --check-prefix LLVM-HIPROC
@@ -94,4 +105,4 @@ FileHeader:
 # LLVM-HIPROC:   Type: 0xFFFF
 
 # GNU-HIPROC: ELF Header:
-# GNU-HIPROC:   Type: ffff
+# GNU-HIPROC:   Type: Processor Specific: (ffff)

llvm/test/tools/llvm-readobj/ELF/types.test

@@ -3526,8 +3526,20 @@ template <class ELFT> void GNUStyle<ELFT>::printFileHeaders() {
   printFields(OS, "OS/ABI:", Str);
   printFields(OS,
               "ABI Version:", std::to_string(e.e_ident[ELF::EI_ABIVERSION]));
+
   Str = printEnum(e.e_type, makeArrayRef(ElfObjectFileType));
+  if (e.e_type >= ET_LOPROC) {
+    Str = "Processor Specific: (" + Str + ")";
+  } else if (e.e_type >= ET_LOOS) {
+    Str = "OS Specific: (" + Str + ")";
+  } else if (makeArrayRef(ElfObjectFileType).end() ==
+             llvm::find_if(ElfObjectFileType,
+                           [&](const EnumEntry<unsigned> &E) {
+                             return E.Value == e.e_type;
+                           }))
+    Str = "<unknown>: " + Str;
   printFields(OS, "Type:", Str);
+
   Str = printEnum(e.e_machine, makeArrayRef(ElfMachineType));
   printFields(OS, "Machine:", Str);
   Str = "0x" + to_hexString(e.e_version);