llvm-objdump -m -D should disassemble all text segments

[mtrent]

Summary

When running llvm-objdump with the -macho option objdump will by default
disassemble only the TEXT,text section (or TEXT_EXEC,text when
disassembling MH_KEXT_BUNDLE files). The -disassemble-all option is
treated no diferently than -disassemble.

This change upates llvm-objdump's MachO parsing code to disassemble all
text sections found in a file when -disassemble-all is specified. This
is useful for disassembling files with more than one text section, or
when disassembling files whose text section is not present in TEXT.

I added a lit test case that verifies "llvm-objdump -m -d" and
"llvm-objdump -m -D" produce the expected results on a reference binary.
I also updated the CommandGuide documentation for llvm-objdump.rst and
verified it renders correctly as man and html.

rdar://42899338

[mtrent]

Fix whitespace indenting

[mtrent]

Fix whitespace indenting for real this time

[lhames]

LGTM!

llvm/trunk/docs/CommandGuide/llvm-objdump.rst

 The :program:`llvm-objdump` utility prints the contents of object files and
 final linked images named on the command line. If no file name is specified,
 :program:`llvm-objdump` will attempt to read from *a.out*. If *-* is used as a
 file name, :program:`llvm-objdump` will process a file on its standard input
 stream.
 
 COMMANDS
 --------
-At least one of the following commands are required, and some commands can be combined with other commands:
+At least one of the following commands are required, and some commands can be
+combined with other commands:
 
-.. option:: -disassemble
+.. option:: -d, -disassemble
 
-  Display assembler mnemonics for the machine instructions
- 
+  Display assembler mnemonics for the machine instructions. Disassembles all
+  text sections found in the input file(s).
+
+.. option:: -D, -disassemble-all
+
+  Display assembler mnemonics for the machine instructions. Disassembles all
+  sections found in the input file(s).
 .. option:: -help
 
   Display usage information and exit. Does not stack with other commands.
 
 .. option:: -r
 
   Display the relocation entries in the file.
 
 .. option:: -s
 
   Display the content of each section.
 
 .. option:: -section-headers
 
   Display summaries of the headers for each section.
 
 .. option:: -t
 
   Display the symbol table.
 
 .. option:: -version
 
   Display the version of this program. Does not stack with other commands.
-  
 OPTIONS
 -------
 :program:`llvm-objdump` supports the following options:
 
 .. option:: -arch=<architecture>
 
-  Specify the architecture to disassemble. see -version for available
+  Specify the architecture to disassemble. see ``-version`` for available
   architectures.
 
 .. option:: -cfg
 
   Create a CFG for every symbol in the object file and write it to a graphviz
   file (Mach-O-only).
 
 .. option:: -dsym=<string>
 
   Use .dSYM file for debug info.
 
 .. option:: -g
 
   Print line information from debug info if available.
 
-.. option:: -macho
+.. option:: -m, -macho
 
-  Use Mach-O specific object file parser.
+  Use Mach-O specific object file parser. Commands and other options may behave
+  differently when used with ``-macho``.
 
 .. option:: -mattr=<a1,+a2,-a3,...>
 
   Target specific attributes.
-  
 .. option:: -mc-x86-disable-arith-relaxation
 
   Disable relaxation of arithmetic instruction for X86.
 
 .. option:: -stats
 
   Enable statistics output from program.
-  
 .. option:: -triple=<string>
 
-  Target triple to disassemble for, see -version for available targets.
-  
+  Target triple to disassemble for, see ``-version`` for available targets.
 .. option:: -x86-asm-syntax=<style>
 
   When used with the ``-disassemble`` option, choose style of code to emit from
   X86 backend. Supported values are:
 
    .. option:: att
-   
     AT&T-style assembly
-   
    .. option:: intel
-   
     Intel-style assembly
 
-   
-  The default disassembly style is **att**. 
+  The default disassembly style is **att**.
 
 BUGS
 ----
 
 To report bugs, please visit <http://llvm.org/bugs/>.
 
 SEE ALSO
 --------
 
 :manpage:`llvm-nm(1)`

llvm/trunk/test/tools/llvm-objdump/X86/macho-disassemble-all.test

+// RUN: llvm-objdump -m -d -full-leading-addr -print-imm-hex -no-show-raw-insn %p/Inputs/macho-multiple-text | FileCheck %s -check-prefix=TEXT
+
+TEXT:      (__TEXT,__text) section
+TEXT_NEXT: _main:
+TEXT_NEXT: 0000000100000f60 pushq %rbp
+TEXT_NEXT: 0000000100000f61 movq  %rsp, %rbp
+TEXT_NEXT: 0000000100000f64 subq  $0x10, %rsp
+TEXT_NEXT: 0000000100000f68 movl  $0x0, -0x4(%rbp)
+TEXT_NEXT: 0000000100000f6f callq _hello
+TEXT_NEXT: 0000000100000f74 xorl  %eax, %eax
+TEXT_NEXT: 0000000100000f76 addq  $0x10, %rsp
+TEXT_NEXT: 0000000100000f7a popq  %rbp
+TEXT_NEXT: 0000000100000f7b retq
+
+// RUN: llvm-objdump -m -D -full-leading-addr -print-imm-hex -no-show-raw-insn %p/Inputs/macho-multiple-text | FileCheck %s -check-prefix=ALL
+
+ALL:      (__TEXT,__text) section
+ALL_NEXT: _main:
+ALL_NEXT: 0000000100000f60  pushq %rbp
+ALL_NEXT: 0000000100000f61  movq  %rsp, %rbp
+ALL_NEXT: 0000000100000f64  subq  $0x10, %rsp
+ALL_NEXT: 0000000100000f68  movl  $0x0, -0x4(%rbp)
+ALL_NEXT: 0000000100000f6f  callq _hello
+ALL_NEXT: 0000000100000f74  xorl  %eax, %eax
+ALL_NEXT: 0000000100000f76  addq  $0x10, %rsp
+ALL_NEXT: 0000000100000f7a  popq  %rbp
+ALL_NEXT: 0000000100000f7b  retq
+ALL:      (__TEXT_EXEC,__text) section
+ALL_NEXT: _hello:
+ALL_NEXT: 0000000100001000  pushq %rbp
+ALL_NEXT: 0000000100001001  movq  %rsp, %rbp
+ALL_NEXT: 0000000100001004  subq  $0x10, %rsp
+ALL_NEXT: 0000000100001008  leaq  -0x71(%rip), %rdi ## literal pool for: "hello, world!\n"
+ALL_NEXT: 000000010000100f  movb  $0x0, %al
+ALL_NEXT: 0000000100001011  callq 0x100000f7c ## symbol stub for: _printf
+ALL_NEXT: 0000000100001016  movl  %eax, -0x4(%rbp)
+ALL_NEXT: 0000000100001019  addq  $0x10, %rsp
+ALL_NEXT: 000000010000101d  popq  %rbp
+ALL_NEXT: 000000010000101e  retq

llvm/trunk/tools/llvm-objdump/MachODump.cpp

static void ProcessMachO(StringRef Name, MachOObjectFile *MachOOF,
   }
 
   // If we need the symbol table to do the operation then check it here to
   // produce a good error message as to where the Mach-O file comes from in
   // the error message.
   if (Disassemble || IndirectSymbols || !FilterSections.empty() || UnwindInfo)
     if (Error Err = MachOOF->checkSymbolTable())
       report_error(ArchiveName, FileName, std::move(Err), ArchitectureName);
   
-  if (Disassemble) {
+  if (DisassembleAll) {
+    for (const SectionRef &Section : MachOOF->sections()) {
+      StringRef SectName;
+      Section.getName(SectName);
+      if (SectName.equals("__text")) {
+        DataRefImpl Ref = Section.getRawDataRefImpl();
+        StringRef SegName = MachOOF->getSectionFinalSegmentName(Ref);
+        DisassembleMachO(FileName, MachOOF, SegName, SectName);
+      }
+    }
+  }
+  else if (Disassemble) {
     if (MachOOF->getHeader().filetype == MachO::MH_KEXT_BUNDLE &&
         MachOOF->getHeader().cputype == MachO::CPU_TYPE_ARM64)
       DisassembleMachO(FileName, MachOOF, "__TEXT_EXEC", "__text");
     else
       DisassembleMachO(FileName, MachOOF, "__TEXT", "__text");
   }
   if (IndirectSymbols)
     PrintIndirectSymbols(MachOOF, !NonVerbose);