[llvm-objdump] Start on -chained_fixups for llvm-otool

And --chained-fixups for llvm-objdump.

For now, this only prints the dyld_chained_fixups_header and adds
plumbing for the flag. This will be expanded in future commits.

When Apple's effort to upstream their chained fixups code continues,
we'll replace this code with the then-upstreamed code. But we need
something in the meantime for testing ld64.lld's chained fixups
code.

Update chained-fixups.yaml with a file that actually contains
the chained fixup data (`LinkEditData` doesn't encode it yet,
so use `__LINKEDIT` via `--raw-segment=data`).

Differential Revision: https://reviews.llvm.org/D131890

9 files changed, 155 insertions, 172 deletions

diff --git a/llvm/docs/CommandGuide/llvm-objdump.rst b/llvm/docs/CommandGuide/llvm-objdump.rst
index a06e8ae..19b3339 100644
--- a/llvm/docs/CommandGuide/llvm-objdump.rst
+++ b/llvm/docs/CommandGuide/llvm-objdump.rst
@@ -312,6 +312,10 @@ MACH-O ONLY OPTIONS AND COMMANDS
 
   Disassemble just the specified symbol's instructions.
 
+.. option:: --chained-fixups
+
+  Print chained fixup information.
+
 .. option:: --dyld_info
 
   Print bind and rebase information used by dyld to resolve external
diff --git a/llvm/docs/CommandGuide/llvm-otool.rst b/llvm/docs/CommandGuide/llvm-otool.rst
index c467350..f2ed563 100644
--- a/llvm/docs/CommandGuide/llvm-otool.rst
+++ b/llvm/docs/CommandGuide/llvm-otool.rst
@@ -23,6 +23,10 @@ OPTIONS
 
  Select slice of universal Mach-O file.
 
+.. option:: -chained_fixups
+
+ Print chained fixup information.
+
 .. option:: -C
 
  Print linker optimization hints.
diff --git a/llvm/include/llvm/BinaryFormat/MachO.h b/llvm/include/llvm/BinaryFormat/MachO.h
index 3895965..ac1af5d 100644
--- a/llvm/include/llvm/BinaryFormat/MachO.h
+++ b/llvm/include/llvm/BinaryFormat/MachO.h
@@ -1002,6 +1002,19 @@ struct nlist_64 {
   uint64_t n_value;
 };
 
+// Values for dyld_chained_fixups_header::imports_format.
+enum {
+  DYLD_CHAINED_IMPORT = 1,
+  DYLD_CHAINED_IMPORT_ADDEND = 2,
+  DYLD_CHAINED_IMPORT_ADDEND64 = 3,
+};
+
+// Values for dyld_chained_fixups_header::symbols_format.
+enum {
+  DYLD_CHAINED_SYMBOL_UNCOMPRESSED = 0,
+  DYLD_CHAINED_SYMBOL_ZLIB = 1,
+};
+
 /// Structs for dyld chained fixups.
 /// dyld_chained_fixups_header is the data pointed to by LC_DYLD_CHAINED_FIXUPS
 /// load command.
diff --git a/llvm/test/tools/llvm-objdump/MachO/chained-fixups.yaml b/llvm/test/tools/llvm-objdump/MachO/chained-fixups.yaml
index 4072d8d..a3532098 100644
--- a/llvm/test/tools/llvm-objdump/MachO/chained-fixups.yaml
+++ b/llvm/test/tools/llvm-objdump/MachO/chained-fixups.yaml
@@ -1,102 +1,106 @@
 # RUN: yaml2obj %s -o %t
 # RUN: llvm-objdump -p %t | FileCheck %s
 # RUN: llvm-otool -l %t | FileCheck %s
-#
+
 # CHECK: LC_DYLD_CHAINED_FIXUPS
 # CHECK: LC_DYLD_EXPORTS_TRIE
 
+# RUN: llvm-objdump --macho --chained-fixups %t | \
+# RUN:     FileCheck --check-prefix=DETAILS -DNAME=%t %s
+# RUN: llvm-otool -chained_fixups %t | \
+# RUN:     FileCheck --check-prefix=DETAILS -DNAME=%t %s
+
+# DETAILS:      [[NAME]]:
+# DETAILS-NEXT: chained fixups header (LC_DYLD_CHAINED_FIXUPS)
+# DETAILS-NEXT:   fixups_version = 0
+# DETAILS-NEXT:   starts_offset  = 32
+# DETAILS-NEXT:   imports_offset = 44
+# DETAILS-NEXT:   symbols_offset = 44
+# DETAILS-NEXT:   imports_count  = 0
+# DETAILS-NEXT:   imports_format = 1 (DYLD_CHAINED_IMPORT)
+# DETAILS-NEXT:   symbols_format = 0
+
+## This yaml is from a dylib produced by ld64
+##   echo ".global _foo\n_foo" > dylib.s
+##   clang -target=x86_64-apple-macos12 -dynamiclib -isysroot Inputs/MacOSX.sdk dylib.s -o libdylib.dylib
+##   obj2yaml --raw-segment=data libdylib.dylib
 --- !mach-o
 FileHeader:
   magic:           0xFEEDFACF
-  cputype:         0x100000C
-  cpusubtype:      0x0
-  filetype:        0x2
-  ncmds:           16
-  sizeofcmds:      744
-  flags:           0x200085
+  cputype:         0x1000007
+  cpusubtype:      0x3
+  filetype:        0x6
+  ncmds:           13
+  sizeofcmds:      568
+  flags:           0x100085
   reserved:        0x0
 LoadCommands:
   - cmd:             LC_SEGMENT_64
-    cmdsize:         72
-    segname:         __PAGEZERO
-    vmaddr:          0
-    vmsize:          4294967296
-    fileoff:         0
-    filesize:        0
-    maxprot:         0
-    initprot:        0
-    nsects:          0
-    flags:           0
-  - cmd:             LC_SEGMENT_64
-    cmdsize:         232
+    cmdsize:         152
     segname:         __TEXT
-    vmaddr:          4294967296
+    vmaddr:          0
     vmsize:          16384
     fileoff:         0
     filesize:        16384
     maxprot:         5
     initprot:        5
-    nsects:          2
+    nsects:          1
     flags:           0
     Sections:
       - sectname:        __text
         segname:         __TEXT
-        addr:            0x100003F98
-        size:            24
-        offset:          0x3F98
-        align:           2
+        addr:            0x4000
+        size:            0
+        offset:          0x4000
+        align:           0
         reloff:          0x0
         nreloc:          0
         flags:           0x80000400
         reserved1:       0x0
         reserved2:       0x0
         reserved3:       0x0
-        content:         C0035FD6FF4300D100008052FF0F00B9FF430091C0035FD6
-      - sectname:        __unwind_info
-        segname:         __TEXT
-        addr:            0x100003FB0
-        size:            80
-        offset:          0x3FB0
-        align:           2
-        reloff:          0x0
-        nreloc:          0
-        flags:           0x0
-        reserved1:       0x0
-        reserved2:       0x0
-        reserved3:       0x0
-        content:         010000001C000000000000001C000000000000001C00000002000000983F00003400000034000000B13F00000000000034000000030000000C0002001400020000000001040000000010000200000002
+        content:         ''
   - cmd:             LC_SEGMENT_64
     cmdsize:         72
     segname:         __LINKEDIT
-    vmaddr:          4294983680
+    vmaddr:          16384
     vmsize:          16384
     fileoff:         16384
-    filesize:        753
+    filesize:        96
     maxprot:         1
     initprot:        1
     nsects:          0
     flags:           0
+  - cmd:             LC_ID_DYLIB
+    cmdsize:         48
+    dylib:
+      name:            24
+      timestamp:       1
+      current_version: 0
+      compatibility_version: 0
+    Content:         libdylib.dylib
+    ZeroPadBytes:    3
   - cmd:             LC_DYLD_CHAINED_FIXUPS
     cmdsize:         16
     dataoff:         16384
-    datasize:        56
+    datasize:        48
   - cmd:             LC_DYLD_EXPORTS_TRIE
     cmdsize:         16
-    dataoff:         16440
-    datasize:        56
+    dataoff:         16432
+    datasize:        16
   - cmd:             LC_SYMTAB
     cmdsize:         24
-    symoff:          16504
-    nsyms:           15
-    stroff:          16744
-    strsize:         120
+    symoff:          16456
+    nsyms:           1
+    stroff:          16472
+    strsize:         8
   - cmd:             LC_DYSYMTAB
     cmdsize:         80
     ilocalsym:       0
-    nlocalsym:       12
-    iextdefsym:      12
-    nextdefsym:      3
-    iundefsym:       15
+    nlocalsym:       0
+    iextdefsym:      0
+    nextdefsym:      1
+    iundefsym:       1
     nundefsym:       0
     tocoff:          0
     ntoc:            0
@@ -110,136 +114,37 @@ LoadCommands:
     nextrel:         0
     locreloff:       0
     nlocrel:         0
-  - cmd:             LC_LOAD_DYLINKER
-    cmdsize:         32
-    name:            12
-    Content:         '/usr/lib/dyld'
-    ZeroPadBytes:    7
   - cmd:             LC_UUID
     cmdsize:         24
-    uuid:            F445529E-643C-3A38-8F59-AB64566BCAFF
+    uuid:            52409B91-DF59-346A-A63F-D4E6FFDC3E04
   - cmd:             LC_BUILD_VERSION
     cmdsize:         32
     platform:        1
     minos:           786432
-    sdk:             786432
+    sdk:             851968
     ntools:          1
     Tools:
       - tool:            3
-        version:         46596096
+        version:         53674242
   - cmd:             LC_SOURCE_VERSION
     cmdsize:         16
     version:         0
-  - cmd:             LC_MAIN
-    cmdsize:         24
-    entryoff:        16284
-    stacksize:       0
   - cmd:             LC_LOAD_DYLIB
     cmdsize:         56
     dylib:
       name:            24
       timestamp:       2
-      current_version: 85917696
+      current_version: 65793
       compatibility_version: 65536
-    Content:         '/usr/lib/libSystem.B.dylib'
-    ZeroPadBytes:    6
+    Content:         '/usr/lib/libSystem.dylib'
+    ZeroPadBytes:    8
   - cmd:             LC_FUNCTION_STARTS
     cmdsize:         16
-    dataoff:         16496
+    dataoff:         16448
     datasize:        8
   - cmd:             LC_DATA_IN_CODE
     cmdsize:         16
-    dataoff:         16504
+    dataoff:         16456
     datasize:        0
-  - cmd:             LC_CODE_SIGNATURE
-    cmdsize:         16
-    dataoff:         16864
-    datasize:        273
-LinkEditData:
-  NameList:
-    - n_strx:          33
-      n_type:          0x64
-      n_sect:          0
-      n_desc:          0
-      n_value:         0
-    - n_strx:          39
-      n_type:          0x64
-      n_sect:          0
-      n_desc:          0
-      n_value:         0
-    - n_strx:          46
-      n_type:          0x66
-      n_sect:          0
-      n_desc:          1
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-    - n_strx:          1
-      n_type:          0x2E
-      n_sect:          1
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-      n_value:         4294983576
-    - n_strx:          109
-      n_type:          0x24
-      n_sect:          1
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-      n_value:         4294983576
-    - n_strx:          1
-      n_type:          0x24
-      n_sect:          0
-      n_desc:          0
-      n_value:         4
-    - n_strx:          1
-      n_type:          0x4E
-      n_sect:          1
-      n_desc:          0
-      n_value:         4
-    - n_strx:          1
-      n_type:          0x2E
-      n_sect:          1
-      n_desc:          0
-      n_value:         4294983580
-    - n_strx:          114
-      n_type:          0x24
-      n_sect:          1
-      n_desc:          0
-      n_value:         4294983580
-    - n_strx:          1
-      n_type:          0x24
-      n_sect:          0
-      n_desc:          0
-      n_value:         20
-    - n_strx:          1
-      n_type:          0x4E
-      n_sect:          1
-      n_desc:          0
-      n_value:         20
-    - n_strx:          1
-      n_type:          0x64
-      n_sect:          1
-      n_desc:          0
-      n_value:         0
-    - n_strx:          2
-      n_type:          0xF
-      n_sect:          1
-      n_desc:          16
-      n_value:         4294967296
-    - n_strx:          22
-      n_type:          0xF
-      n_sect:          1
-      n_desc:          0
-      n_value:         4294983576
-    - n_strx:          27
-      n_type:          0xF
-      n_sect:          1
-      n_desc:          0
-      n_value:         4294983580
-  StringTable:
-    - ' '
-    - __mh_execute_header
-    - _foo
-    - _main
-    - '/tmp/'
-    - main.c
-    - '/var/folders/gj/wf3swl0x215b2sq1qy84kzkm0000gn/T/main-e32fe7.o'
-    - _foo
-    - _main
+__LINKEDIT:      00000000200000002C0000002C000000000000000100000000000000000000000200000000000000000000000000000000015F666F6F000804008080010000000000000000000000020000000F010000004000000000000020005F666F6F0000
 ...
diff --git a/llvm/tools/llvm-objdump/MachODump.cpp b/llvm/tools/llvm-objdump/MachODump.cpp
index cdbecd5..a2593cf 100644
--- a/llvm/tools/llvm-objdump/MachODump.cpp
+++ b/llvm/tools/llvm-objdump/MachODump.cpp
@@ -81,6 +81,7 @@ bool objdump::DataInCode;
 bool objdump::FunctionStarts;
 bool objdump::LinkOptHints;
 bool objdump::InfoPlist;
+bool objdump::ChainedFixups;
 bool objdump::DyldInfo;
 bool objdump::DylibsUsed;
 bool objdump::DylibId;
@@ -112,6 +113,7 @@ void objdump::parseMachOOptions(const llvm::opt::InputArgList &InputArgs) {
   FunctionStarts = InputArgs.hasArg(OBJDUMP_function_starts);
   LinkOptHints = InputArgs.hasArg(OBJDUMP_link_opt_hints);
   InfoPlist = InputArgs.hasArg(OBJDUMP_info_plist);
+  ChainedFixups = InputArgs.hasArg(OBJDUMP_chained_fixups);
   DyldInfo = InputArgs.hasArg(OBJDUMP_dyld_info);
   DylibsUsed = InputArgs.hasArg(OBJDUMP_dylibs_used);
   DylibId = InputArgs.hasArg(OBJDUMP_dylib_id);
@@ -1193,6 +1195,48 @@ static void printMachOChainedFixups(object::MachOObjectFile *Obj) {
     reportError(std::move(Err), Obj->getFileName());
 }
 
+static void
+PrintChainedFixupsHeader(const MachO::dyld_chained_fixups_header &H) {
+  outs() << "chained fixups header (LC_DYLD_CHAINED_FIXUPS)\n";
+  outs() << "  fixups_version = " << H.fixups_version << '\n';
+  outs() << "  starts_offset  = " << H.starts_offset << '\n';
+  outs() << "  imports_offset = " << H.imports_offset << '\n';
+  outs() << "  symbols_offset = " << H.symbols_offset << '\n';
+  outs() << "  imports_count  = " << H.imports_count << '\n';
+
+  outs() << "  imports_format = " << H.imports_format;
+  switch (H.imports_format) {
+  case llvm::MachO::DYLD_CHAINED_IMPORT:
+    outs() << " (DYLD_CHAINED_IMPORT)";
+    break;
+  case llvm::MachO::DYLD_CHAINED_IMPORT_ADDEND:
+    outs() << " (DYLD_CHAINED_IMPORT_ADDEND)";
+    break;
+  case llvm::MachO::DYLD_CHAINED_IMPORT_ADDEND64:
+    outs() << " (DYLD_CHAINED_IMPORT_ADDEND64)";
+    break;
+  }
+  outs() << '\n';
+
+  outs() << "  symbols_format = " << H.symbols_format;
+  if (H.symbols_format == llvm::MachO::DYLD_CHAINED_SYMBOL_ZLIB)
+    outs() << " (zlib compressed)";
+  outs() << '\n';
+}
+
+static void PrintChainedFixups(MachOObjectFile *O) {
+  // MachOObjectFile::getChainedFixupsHeader() reads LC_DYLD_CHAINED_FIXUPS.
+  // FIXME: Support chained fixups in __TEXT,__chain_starts section too.
+  auto ChainedFixupHeader =
+      unwrapOrError(O->getChainedFixupsHeader(), O->getFileName());
+  if (!ChainedFixupHeader)
+    return;
+
+  PrintChainedFixupsHeader(*ChainedFixupHeader);
+
+  // FIXME: Print more things.
+}
+
 static void PrintDyldInfo(MachOObjectFile *O) {
   outs() << "dyld information:" << '\n';
   printMachOChainedFixups(O);
@@ -1916,8 +1960,9 @@ static void ProcessMachO(StringRef Name, MachOObjectFile *MachOOF,
   // UniversalHeaders or ArchiveHeaders.
   if (Disassemble || Relocations || PrivateHeaders || ExportsTrie || Rebase ||
       Bind || SymbolTable || LazyBind || WeakBind || IndirectSymbols ||
-      DataInCode || FunctionStarts || LinkOptHints || DyldInfo || DylibsUsed ||
-      DylibId || Rpaths || ObjcMetaData || (!FilterSections.empty())) {
+      DataInCode || FunctionStarts || LinkOptHints || ChainedFixups ||
+      DyldInfo || DylibsUsed || DylibId || Rpaths || ObjcMetaData ||
+      (!FilterSections.empty())) {
     if (LeadingHeaders) {
       outs() << Name;
       if (!ArchiveMemberName.empty())
@@ -1986,6 +2031,8 @@ static void ProcessMachO(StringRef Name, MachOObjectFile *MachOOF,
     DumpSectionContents(FileName, MachOOF, Verbose);
   if (InfoPlist)
     DumpInfoPlistSectionContents(FileName, MachOOF);
+  if (ChainedFixups)
+    PrintChainedFixups(MachOOF);
   if (DyldInfo)
     PrintDyldInfo(MachOOF);
   if (DylibsUsed)
diff --git a/llvm/tools/llvm-objdump/MachODump.h b/llvm/tools/llvm-objdump/MachODump.h
index 12783e1..3292042 100644
--- a/llvm/tools/llvm-objdump/MachODump.h
+++ b/llvm/tools/llvm-objdump/MachODump.h
@@ -36,6 +36,7 @@ void parseMachOOptions(const llvm::opt::InputArgList &InputArgs);
 extern bool Bind;
 extern bool DataInCode;
 extern std::string DisSymName;
+extern bool ChainedFixups;
 extern bool DyldInfo;
 extern bool DylibId;
 extern bool DylibsUsed;
diff --git a/llvm/tools/llvm-objdump/ObjdumpOpts.td b/llvm/tools/llvm-objdump/ObjdumpOpts.td
index 00d7d8c..acfdf00 100644
--- a/llvm/tools/llvm-objdump/ObjdumpOpts.td
+++ b/llvm/tools/llvm-objdump/ObjdumpOpts.td
@@ -299,11 +299,15 @@ def info_plist : Flag<["--"], "info-plist">,
            "Mach-O objects (requires --macho)">,
   Group<grp_mach_o>;
 
+def chained_fixups : Flag<["--"], "chained-fixups">,
+  HelpText<"Print chained fixup information (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>;
+  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 "
diff --git a/llvm/tools/llvm-objdump/OtoolOpts.td b/llvm/tools/llvm-objdump/OtoolOpts.td
index e8bef28..71ac541 100644
--- a/llvm/tools/llvm-objdump/OtoolOpts.td
+++ b/llvm/tools/llvm-objdump/OtoolOpts.td
@@ -37,13 +37,15 @@ def V : Flag<["-"], "V">,
 def x : Flag<["-"], "x">, HelpText<"print all text sections">;
 def X : Flag<["-"], "X">, HelpText<"omit leading addresses or headers">;
 
+def chained_fixups : Flag<["-"], "chained_fixups">,
+  HelpText<"print chained fixup information">;
+
 // 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
 
diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index efac3a8..f7b4814 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -2787,6 +2787,8 @@ static void parseOtoolOptions(const llvm::opt::InputArgList &InputArgs) {
     FilterSections.push_back(",__text");
   LeadingAddr = LeadingHeaders = !InputArgs.hasArg(OTOOL_X);
 
+  ChainedFixups = InputArgs.hasArg(OTOOL_chained_fixups);
+
   InputFilenames = InputArgs.getAllArgValues(OTOOL_INPUT);
   if (InputFilenames.empty())
     reportCmdLineError("no input file");
@@ -2990,11 +2992,12 @@ int main(int argc, char **argv) {
       !DynamicRelocations && !FileHeaders && !PrivateHeaders && !RawClangAST &&
       !Relocations && !SectionHeaders && !SectionContents && !SymbolTable &&
       !DynamicSymbolTable && !UnwindInfo && !FaultMapSection && !Offloading &&
-      !(MachOOpt && (Bind || DataInCode || DyldInfo || DylibId || DylibsUsed ||
-                     ExportsTrie || FirstPrivateHeader || FunctionStarts ||
-                     IndirectSymbols || InfoPlist || LazyBind || LinkOptHints ||
-                     ObjcMetaData || Rebase || Rpaths || UniversalHeaders ||
-                     WeakBind || !FilterSections.empty()))) {
+      !(MachOOpt &&
+        (Bind || DataInCode || ChainedFixups || DyldInfo || DylibId ||
+         DylibsUsed || ExportsTrie || FirstPrivateHeader || FunctionStarts ||
+         IndirectSymbols || InfoPlist || LazyBind || LinkOptHints ||
+         ObjcMetaData || Rebase || Rpaths || UniversalHeaders || WeakBind ||
+         !FilterSections.empty()))) {
     T->printHelp(ToolName);
     return 2;
   }