Add a (nonfunctional) -dyld_info flag to llvm-objdump.

[aprantl]

Summary

Darwin otool implements this flag as a one-stop solution for displaying bind and rebase info. As I am working on upstreaming chained fixup support this command will be useful to write testcases.

[jhenderson]

Please remember to add new options to the .rst file for llvm-otool.

What's the motivation for adding the option without implementation at this point?

llvm/test/tools/llvm-objdump/MachO/dyld_info.test

3

Probably want to add --implicit-check-not={{.}} to catch any new/additional output too.

I have a slight personal preference for putting the | at the end of the continued line, to indicate that the next line will be the start of a new command entirely, but I'm not fussed either way.

llvm/tools/llvm-objdump/MachODump.cpp

1187–1189

I don't think we usually bother with these sorts of comments? NB: I haven't bothered looking at the context, so there may be precedent in this file for it.

[aprantl]

What's the motivation for adding the option without implementation at this point?

This patch is part of a series of patches to upstream chained fixup support in MachOObjectFile and I need an implementation of -dyld_info to write tests for that feature. I'm trying break the patch into small pieces to make reviewing easier. With every patch the implementation will become more complete.

llvm/tools/llvm-objdump/MachODump.cpp

1187–1189

You're right, the rest of the file also doesn't use them.

[aprantl]

Address review feedback.

[jhenderson]

llvm/test/tools/llvm-objdump/MachO/dyld_info.test

7–8

Consider also CHECK-NEXT, for full clarity (not needed for test explicitness, thanks to --strict-whitespace, but might make it easier to follow what is the exact output for those not looking at the FileCheck command line).

llvm/tools/llvm-objdump/MachODump.cpp

1188

llvm/tools/llvm-objdump/ObjdumpOpts.td

300–301

1. Other Mach-O specific options state something like "(requires --macho)" in their help text.
2. Other options don't look to have a trailing full stop.

llvm/tools/llvm-objdump/OtoolOpts.td

44

You're removing this option from the list of llvm-otool unsupported options, but as I understand it, you've added the option to llvm-objdump, but not llvm-otool. I'm not sure that's quite right?

[aprantl]

Address review feedback

[keith]

llvm/docs/CommandGuide/llvm-objdump.rst

305

It looks like all of the llvm-objdump flags today use dashes and not underscores, I know this matches apple's otool instead, but I wonder if it would be better to be consistent with the other ones in this version

[jhenderson]

LGTM from my point of view.

[aprantl]

llvm/docs/CommandGuide/llvm-objdump.rst

305

this matches apple's otool instead

that's the only reason for the name, yes.

llvm/docs/CommandGuide/llvm-objdump.rst

 .. option:: --data-in-code
 
   Display the data in code table.
 
 .. option:: --dis-symname=<name>
 
   Disassemble just the specified symbol's instructions.
 
+.. option:: --dyld_info
+
+  Print bind and rebase information used by dyld to resolve external
+  references in a final linked binary.
+
 .. option:: --dylibs-used
 
   Display the shared libraries used for linked files.
 
 .. option:: --dsym=<string>
 
   Use .dSYM file for debug info.
 

llvm/test/tools/llvm-objdump/MachO/dyld_info.test

+RUN: llvm-objdump --macho --dyld_info %p/Inputs/bind.macho-x86_64 \
+RUN:   | FileCheck %s --match-full-lines --strict-whitespace \
+RUN:     --implicit-check-not={{.}}
+
+CHECK:{{.*}}bind.macho-x86_64:
+CHECK-NEXT:dyld information:
+CHECK-NEXT:[not yet implemented].

llvm/tools/llvm-objdump/MachODump.h

 namespace objdump {
 
 void parseMachOOptions(const llvm::opt::InputArgList &InputArgs);
 
 // MachO specific options
 extern bool Bind;
 extern bool DataInCode;
 extern std::string DisSymName;
+extern bool DyldInfo;
 extern bool DylibId;
 extern bool DylibsUsed;
 extern bool ExportsTrie;
 extern bool FirstPrivateHeader;
 extern bool FullLeadingAddr;
 extern bool FunctionStarts;
 extern bool IndirectSymbols;
 extern bool InfoPlist;

llvm/tools/llvm-objdump/MachODump.cpp

 bool objdump::LeadingHeaders;
 bool objdump::UniversalHeaders;
 static bool ArchiveMemberOffsets;
 bool objdump::IndirectSymbols;
 bool objdump::DataInCode;
 bool objdump::FunctionStarts;
 bool objdump::LinkOptHints;
 bool objdump::InfoPlist;
+bool objdump::DyldInfo;
 bool objdump::DylibsUsed;
 bool objdump::DylibId;
 bool objdump::Verbose;
 bool objdump::ObjcMetaData;
 std::string objdump::DisSymName;
 bool objdump::SymbolicOperands;
 static std::vector<std::string> ArchFlags;
 
void objdump::parseMachOOptions(const llvm::opt::InputArgList &InputArgs) {
   LeadingHeaders = !InputArgs.hasArg(OBJDUMP_no_leading_headers);
   UniversalHeaders = InputArgs.hasArg(OBJDUMP_universal_headers);
   ArchiveMemberOffsets = InputArgs.hasArg(OBJDUMP_archive_member_offsets);
   IndirectSymbols = InputArgs.hasArg(OBJDUMP_indirect_symbols);
   DataInCode = InputArgs.hasArg(OBJDUMP_data_in_code);
   FunctionStarts = InputArgs.hasArg(OBJDUMP_function_starts);
   LinkOptHints = InputArgs.hasArg(OBJDUMP_link_opt_hints);
   InfoPlist = InputArgs.hasArg(OBJDUMP_info_plist);
+  DyldInfo = InputArgs.hasArg(OBJDUMP_dyld_info);
   DylibsUsed = InputArgs.hasArg(OBJDUMP_dylibs_used);
   DylibId = InputArgs.hasArg(OBJDUMP_dylib_id);
   Verbose = !InputArgs.hasArg(OBJDUMP_non_verbose);
   ObjcMetaData = InputArgs.hasArg(OBJDUMP_objc_meta_data);
   DisSymName = InputArgs.getLastArgValue(OBJDUMP_dis_symname).str();
   SymbolicOperands = !InputArgs.hasArg(OBJDUMP_no_symbolic_operands);
   ArchFlags = InputArgs.getAllArgValues(OBJDUMP_arch_EQ);
 }
for (uint32_t j = 0; j < narguments; j++) {
       i += n;
       outs() << "\tvalue " << format("0x%" PRIx64, value) << "\n";
       if (i >= nloh)
         return;
     }
   }
 }
 
+static void PrintDyldInfo(MachOObjectFile *O) {
+  outs() << "dyld information:\n";
+  outs() << "[not yet implemented].\n";
+}
+
 static void PrintDylibs(MachOObjectFile *O, bool JustId) {
   unsigned Index = 0;
   for (const auto &Load : O->load_commands()) {
     if ((JustId && Load.C.cmd == MachO::LC_ID_DYLIB) ||
         (!JustId && (Load.C.cmd == MachO::LC_ID_DYLIB ||
                      Load.C.cmd == MachO::LC_LOAD_DYLIB ||
                      Load.C.cmd == MachO::LC_LOAD_WEAK_DYLIB ||
                      Load.C.cmd == MachO::LC_REEXPORT_DYLIB ||

 static void ProcessMachO(StringRef Name, MachOObjectFile *MachOOF,
                          StringRef ArchiveMemberName = StringRef(),
                          StringRef ArchitectureName = StringRef()) {
   // If we are doing some processing here on the Mach-O file print the header
   // info.  And don't print it otherwise like in the case of printing the
   // UniversalHeaders or ArchiveHeaders.
   if (Disassemble || Relocations || PrivateHeaders || ExportsTrie || Rebase ||
       Bind || SymbolTable || LazyBind || WeakBind || IndirectSymbols ||
-      DataInCode || FunctionStarts || LinkOptHints || DylibsUsed || DylibId ||
-      Rpaths || ObjcMetaData || (!FilterSections.empty())) {
+      DataInCode || FunctionStarts || LinkOptHints || DyldInfo || DylibsUsed ||
+      DylibId || Rpaths || ObjcMetaData || (!FilterSections.empty())) {
     if (LeadingHeaders) {
       outs() << Name;
       if (!ArchiveMemberName.empty())
         outs() << '(' << ArchiveMemberName << ')';
       if (!ArchitectureName.empty())
         outs() << " (architecture " << ArchitectureName << ")";
       outs() << ":\n";
     }
static void ProcessMachO(StringRef Name, MachOObjectFile *MachOOF,
   if (SectionHeaders)
     printSectionHeaders(MachOOF);
   if (SectionContents)
     printSectionContents(MachOOF);
   if (!FilterSections.empty())
     DumpSectionContents(FileName, MachOOF, Verbose);
   if (InfoPlist)
     DumpInfoPlistSectionContents(FileName, MachOOF);
+  if (DyldInfo)
+    PrintDyldInfo(MachOOF);
   if (DylibsUsed)
     PrintDylibs(MachOOF, false);
   if (DylibId)
     PrintDylibs(MachOOF, true);
   if (SymbolTable)
     printSymbolTable(MachOOF, ArchiveName, ArchitectureName);
   if (UnwindInfo)
     printMachOUnwindInfo(MachOOF);

llvm/tools/llvm-objdump/ObjdumpOpts.td

HelpText<"Print the linker optimization hints for "
            "Mach-O objects (requires --macho)">,
   Group<grp_mach_o>;
 
 def info_plist : Flag<["--"], "info-plist">,
   HelpText<"Print the info plist section as strings for "
            "Mach-O objects (requires --macho)">,
   Group<grp_mach_o>;
 
+def dyld_info : Flag<["--"], "dyld_info">,
+      HelpText<"Print bind and rebase information used by dyld to resolve "
+               "external references in a final linked binary "
+               "(requires --macho)">,
+      Group<grp_mach_o>;
+
 def dylibs_used : Flag<["--"], "dylibs-used">,
   HelpText<"Print the shared libraries used for linked "
            "Mach-O files (requires --macho)">,
   Group<grp_mach_o>;
 
 def dylib_id : Flag<["--"], "dylib-id">,
   HelpText<"Print the shared library's id for the "
            "dylib Mach-O file (requires --macho)">,

llvm/tools/llvm-objdump/OtoolOpts.td

def V : Flag<["-"], "V">,
   HelpText<"symbolize disassembled operands (implies -v)">;
 def x : Flag<["-"], "x">, HelpText<"print all text sections">;
 def X : Flag<["-"], "X">, HelpText<"omit leading addresses or headers">;
 
 // Not (yet?) implemented:
 // def a : Flag<["-"], "a">, HelpText<"print archive header">;
 // -c print argument strings of a core file
 // -m don't use archive(member) syntax
 // -dyld_info
 // -dyld_opcodes
 // -chained_fixups
 // -addr_slide=arg
 // -function_offsets
 
-
 // Obsolete and unsupported:
 def grp_obsolete : OptionGroup<"kind">,
   HelpText<"Obsolete and unsupported flags">;
 
 def : Flag<["-"], "B">, Flags<[HelpHidden]>, Group<grp_obsolete>,
   HelpText<"force Thum disassembly (ARM 32-bit objects only)">;
 def : Flag<["-"], "H">, Flags<[HelpHidden]>, Group<grp_obsolete>,
   HelpText<"print two-level hints table">;

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

int main(int argc, char **argv) {
   if (DisassembleAll || PrintSource || PrintLines ||
       !DisassembleSymbols.empty())
     Disassemble = true;
 
   if (!ArchiveHeaders && !Disassemble && DwarfDumpType == DIDT_Null &&
       !DynamicRelocations && !FileHeaders && !PrivateHeaders && !RawClangAST &&
       !Relocations && !SectionHeaders && !SectionContents && !SymbolTable &&
       !DynamicSymbolTable && !UnwindInfo && !FaultMapSection &&
-      !(MachOOpt &&
-        (Bind || DataInCode || DylibId || DylibsUsed || ExportsTrie ||
-         FirstPrivateHeader || FunctionStarts || IndirectSymbols || InfoPlist ||
-         LazyBind || LinkOptHints || ObjcMetaData || Rebase || Rpaths ||
-         UniversalHeaders || WeakBind || !FilterSections.empty()))) {
+      !(MachOOpt && (Bind || DataInCode || DyldInfo || DylibId || DylibsUsed ||
+                     ExportsTrie || FirstPrivateHeader || FunctionStarts ||
+                     IndirectSymbols || InfoPlist || LazyBind || LinkOptHints ||
+                     ObjcMetaData || Rebase || Rpaths || UniversalHeaders ||
+                     WeakBind || !FilterSections.empty()))) {
     T->printHelp(ToolName);
     return 2;
   }
 
   DisasmSymbolSet.insert(DisassembleSymbols.begin(), DisassembleSymbols.end());
 
   llvm::for_each(InputFilenames, dumpInput);
 
   warnOnNoMatchForSections();
 
   return EXIT_SUCCESS;
 }