[llvm-objdump] Use "--" for long options in --help text

[DavidSpickett]

Summary

Single dash for these options is not recognised.

Changes found by running this on the --help output
and the user guide:
grep -e ' -[a-zA-Z]\{2,\}'

The user guide was updated in https://reviews.llvm.org/D92305
so no change there.

[jhenderson]

Mostly seems sensible to me. However, you might want to get the opinion of a Mach-O user as to whether the single or double-dash option makes more sense for the Mach-O specific options. I've added a couple of others who I know use Mach-O as reviewers.

[DavidSpickett]

For reference it's listed as --macho in https://llvm.org/docs/CommandGuide/llvm-objdump.html#cmdoption-llvm-objdump-macho. However that page is missing some of the "requires -macho" statements so could be a mistake.

Currently it only accepts --:

$ ./bin/llvm-objdump  /tmp/arm64.o -d -macho
llvm-objdump: Unknown command line argument '-macho'.  Try: './bin/llvm-objdump --help'
llvm-objdump: Did you mean '-h'?
$ ./bin/llvm-objdump  /tmp/arm64.o -d --macho
llvm-objdump: error: /tmp/arm64.o': object is not a Mach-O file type.

But yes, perhaps it is intended to work.

[jhenderson]

It's quite possible there are mistakes in the llvm-objdump docs - I have attempted to get them somewhat clean, but don't really know much about mach-o nor do I use it at all so it's quite likely I've either missed something or accidentally broken some related documentation in my attempts to clean things up! Alterantively, it's quite possible the docs were in a bad state before I even touched them!

[DavidSpickett]

Ping on -macho vs --macho question. Anyone else want to chime in?

(thanks for the review so far)

llvm/tools/llvm-objdump/MachODump.cpp

static cl::opt<bool> FullLeadingAddr("full-leading-addr",
                                      cl::cat(MachOCat));
 
 static cl::opt<bool> NoLeadingHeaders("no-leading-headers",
                                       cl::desc("Print no leading headers"),
                                       cl::cat(MachOCat));
 
 cl::opt<bool> objdump::UniversalHeaders(
     "universal-headers",
-    cl::desc("Print Mach-O universal headers (requires -macho)"),
+    cl::desc("Print Mach-O universal headers (requires --macho)"),
     cl::cat(MachOCat));
 
 static cl::opt<bool> ArchiveMemberOffsets(
     "archive-member-offsets",
     cl::desc("Print the offset to each archive member for Mach-O archives "
-             "(requires -macho and -archive-headers)"),
+             "(requires --macho and --archive-headers)"),
     cl::cat(MachOCat));
 
 cl::opt<bool> objdump::IndirectSymbols(
     "indirect-symbols",
     cl::desc(
-        "Print indirect symbol table for Mach-O objects (requires -macho)"),
+        "Print indirect symbol table for Mach-O objects (requires --macho)"),
     cl::cat(MachOCat));
 
 cl::opt<bool> objdump::DataInCode(
     "data-in-code",
     cl::desc(
-        "Print the data in code table for Mach-O objects (requires -macho)"),
+        "Print the data in code table for Mach-O objects (requires --macho)"),
     cl::cat(MachOCat));
 
 cl::opt<bool>
     objdump::LinkOptHints("link-opt-hints",
                           cl::desc("Print the linker optimization hints for "
-                                   "Mach-O objects (requires -macho)"),
+                                   "Mach-O objects (requires --macho)"),
                           cl::cat(MachOCat));
 
 cl::opt<bool>
     objdump::InfoPlist("info-plist",
                        cl::desc("Print the info plist section as strings for "
-                                "Mach-O objects (requires -macho)"),
+                                "Mach-O objects (requires --macho)"),
                        cl::cat(MachOCat));
 
 cl::opt<bool>
     objdump::DylibsUsed("dylibs-used",
                         cl::desc("Print the shared libraries used for linked "
-                                 "Mach-O files (requires -macho)"),
+                                 "Mach-O files (requires --macho)"),
                         cl::cat(MachOCat));
 
 cl::opt<bool> objdump::DylibId("dylib-id",
                                cl::desc("Print the shared library's id for the "
-                                        "dylib Mach-O file (requires -macho)"),
+                                        "dylib Mach-O file (requires --macho)"),
                                cl::cat(MachOCat));
 
 static cl::opt<bool>
     NonVerbose("non-verbose",
                cl::desc("Print the info for Mach-O objects in non-verbose or "
-                        "numeric form (requires -macho)"),
+                        "numeric form (requires --macho)"),
                cl::cat(MachOCat));
 
 cl::opt<bool>
     objdump::ObjcMetaData("objc-meta-data",
                           cl::desc("Print the Objective-C runtime meta data "
-                                   "for Mach-O files (requires -macho)"),
+                                   "for Mach-O files (requires --macho)"),
                           cl::cat(MachOCat));
 
 static cl::opt<std::string> DisSymName(
     "dis-symname",
-    cl::desc("disassemble just this symbol's instructions (requires -macho)"),
+    cl::desc("disassemble just this symbol's instructions (requires --macho)"),
     cl::cat(MachOCat));
 
 static cl::opt<bool> NoSymbolicOperands(
     "no-symbolic-operands",
-    cl::desc("do not symbolic operands when disassembling (requires -macho)"),
+    cl::desc("do not symbolic operands when disassembling (requires --macho)"),
     cl::cat(MachOCat));
 
 static cl::list<std::string>
     ArchFlags("arch", cl::desc("architecture(s) from a Mach-O file to dump"),
               cl::ZeroOrMore, cl::cat(MachOCat));
 
 static bool ArchAll = false;
 

llvm/tools/llvm-objdump/llvm-objdump.cpp

AllHeaders("all-headers",
                cl::cat(ObjdumpCat));
 static cl::alias AllHeadersShort("x", cl::desc("Alias for --all-headers"),
                                  cl::NotHidden, cl::Grouping,
                                  cl::aliasopt(AllHeaders));
 
 static cl::opt<std::string>
     ArchName("arch-name",
              cl::desc("Target arch to disassemble for, "
-                      "see -version for available targets"),
+                      "see --version for available targets"),
              cl::cat(ObjdumpCat));
 
 cl::opt<bool>
     objdump::ArchiveHeaders("archive-headers",
                             cl::desc("Display archive header information"),
                             cl::cat(ObjdumpCat));
 static cl::alias ArchiveHeadersShort("a",
                                      cl::desc("Alias for --archive-headers"),

 static cl::alias PrivateHeadersShort("p",
                                      cl::desc("Alias for --private-headers"),
                                      cl::NotHidden, cl::Grouping,
                                      cl::aliasopt(PrivateHeaders));
 
 cl::list<std::string>
     objdump::FilterSections("section",
                             cl::desc("Operate on the specified sections only. "
-                                     "With -macho dump segment,section"),
+                                     "With --macho dump segment,section"),
                             cl::cat(ObjdumpCat));
 static cl::alias FilterSectionsj("j", cl::desc("Alias for --section"),
                                  cl::NotHidden, cl::Grouping, cl::Prefix,
                                  cl::aliasopt(FilterSections));
 
 cl::opt<bool> objdump::SectionHeaders(
     "section-headers",
     cl::desc("Display summaries of the headers for each section."),
ShowLMA("show-lma",
             cl::desc("Display LMA column when dumping ELF section headers"),
             cl::cat(ObjdumpCat));
 
 static cl::opt<bool> PrintSource(
     "source",
     cl::desc(
         "Display source inlined with disassembly. Implies disassemble object"),
     cl::cat(ObjdumpCat));
-static cl::alias PrintSourceShort("S", cl::desc("Alias for -source"),
+static cl::alias PrintSourceShort("S", cl::desc("Alias for --source"),
                                   cl::NotHidden, cl::Grouping,
                                   cl::aliasopt(PrintSource));
 
 static cl::opt<uint64_t>
     StartAddress("start-address", cl::desc("Disassemble beginning at address"),
                  cl::value_desc("address"), cl::init(0), cl::cat(ObjdumpCat));
 static cl::opt<uint64_t> StopAddress("stop-address",
                                      cl::desc("Stop disassembly at address"),
static cl::opt<bool> DynamicSymbolTable(
     "dynamic-syms",
     cl::desc("Display the contents of the dynamic symbol table"),
     cl::cat(ObjdumpCat));
 static cl::alias DynamicSymbolTableShort("T",
                                          cl::desc("Alias for --dynamic-syms"),
                                          cl::NotHidden, cl::Grouping,
                                          cl::aliasopt(DynamicSymbolTable));
 
-cl::opt<std::string> objdump::TripleName(
-    "triple",
-    cl::desc(
-        "Target triple to disassemble for, see -version for available targets"),
+cl::opt<std::string>
+    objdump::TripleName("triple",
+                        cl::desc("Target triple to disassemble for, see "
+                                 "--version for available targets"),
                         cl::cat(ObjdumpCat));
 
 cl::opt<bool> objdump::UnwindInfo("unwind-info",
                                   cl::desc("Display unwind information"),
                                   cl::cat(ObjdumpCat));
 static cl::alias UnwindInfoShort("u", cl::desc("Alias for --unwind-info"),
                                  cl::NotHidden, cl::Grouping,
                                  cl::aliasopt(UnwindInfo));