[llvm-readobj] Accept (and ignore) --wide (-W) command-line switch

[mcgrathr]

Summary

Accept and ignore --wide/-W. In GNU readelf this switch is
necessary to get the output format that's consistent between
32-bit and 64-bit targets. llvm-readobj always produces that
output format.

[davide]

LGTM independently from what we decide to do with the options in the end.

[mcgrathr]

I'd appreciate if someone could land this for me. (To land it before its parents will just have some trivial patch conflicts but there is no real interaction between the three changes.)

Thanks,
Roland

[mcgrathr]

One line from this one got dropped into the llvm-readelf patch.

test/tools/llvm-readobj/gnu-sections.test

 RUN: llvm-readobj -s %p/Inputs/relocs.obj.elf-i386 --elf-output-style=GNU \
 RUN:   | FileCheck %s -check-prefix ELF32
 RUN: llvm-readobj -S %p/Inputs/relocs.obj.elf-x86_64 --elf-output-style=GNU \
 RUN:   | FileCheck %s -check-prefix ELF64
+RUN: llvm-readobj --wide --sections \
+RUN:   %p/Inputs/relocs.obj.elf-x86_64 --elf-output-style=GNU \
+RUN:   | FileCheck %s -check-prefix ELF64
+RUN: llvm-readobj -W --sections \
+RUN:   %p/Inputs/relocs.obj.elf-x86_64 --elf-output-style=GNU \
+RUN:   | FileCheck %s -check-prefix ELF64
 
 ELF32:    Section Headers:
 ELF32-NEXT:      [Nr] Name              Type            Address  Off    Size   ES Flg Lk Inf Al
 ELF32-NEXT:      [ 0]                   NULL            00000000 000000 000000 00      0   0  0
 ELF32-NEXT:      [ 1] .text             PROGBITS        00000000 000034 0000f6 00  AX  0   0  4
 ELF32-NEXT:      [ 2] .rel.text         REL             00000000 000318 000148 08      6   1  4
 ELF32-NEXT:      [ 3] .data             PROGBITS        00000000 00012c 000000 00  WA  0   0  4
 ELF32-NEXT:      [ 4] .bss              NOBITS          00000000 00012c 000000 00  WA  0   0  4

tools/llvm-readobj/llvm-readobj.cpp

 using namespace llvm;
 using namespace llvm::object;
 
 namespace opts {
   cl::list<std::string> InputFilenames(cl::Positional,
     cl::desc("<input object files>"),
     cl::ZeroOrMore);
 
+  // -wide, -W
+  cl::opt<bool> WideOutput("wide",
+    cl::desc("Ignored for compatibility with GNU readelf"));
+  cl::alias WideOutputShort("W",
+    cl::desc("Alias for --wide"),
+    cl::aliasopt(WideOutput));
+
   // -file-headers, -h
   cl::opt<bool> FileHeaders("file-headers",
     cl::desc("Display file headers "));
   cl::alias FileHeadersShort("h",
     cl::desc("Alias for --file-headers"),
     cl::aliasopt(FileHeaders));
 
   // -sections, -s, -S