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

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

Reviewers: ab, pete, lhames

Reviewed By: lhames

Subscribers: rupprecht, llvm-commits

Differential Revision: https://reviews.llvm.org/D56649

llvm-svn: 351238
This commit is contained in:
Michael Trent 2019-01-15 20:41:30 +00:00
parent d6a9bbf68e
commit 7e6602110b
4 changed files with 77 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
llvm/docs/CommandGuide/llvm-objdump.rst
View File

@ -16,12 +16,19 @@ 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. 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).
Display assembler mnemonics for the machine instructions
.. option:: -help
Display usage information and exit. Does not stack with other commands.
@ -45,14 +52,14 @@ At least one of the following commands are required, and some commands can be co
.. 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
@ -68,14 +75,15 @@ OPTIONS
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.
@ -83,26 +91,26 @@ OPTIONS
.. 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
----

BIN
llvm/test/tools/llvm-objdump/X86/Inputs/macho-multiple-text Executable file
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Binary file not shown.

39
llvm/test/tools/llvm-objdump/X86/macho-disassemble-all.test Normal file
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@ -0,0 +1,39 @@
// 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

15
llvm/tools/llvm-objdump/MachODump.cpp
View File

@ -1610,8 +1610,19 @@ static void ProcessMachO(StringRef Name, MachOObjectFile *MachOOF,
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");