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Merged
cuviper merged 2 commits into from
Jun 24, 2026
Merged

Backport #203680 and #205044 #198

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6758c39
[llvm-objcopy][MachO] Align __LINKEDIT entries to pointer size (#203680)
goranmoomin Jun 20, 2026
3c3f130
[yaml2obj][MachO] Fix byte order of the indirect symbol table (#205044)
goranmoomin Jun 22, 2026
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85 changes: 51 additions & 34 deletions llvm/lib/ObjCopy/MachO/MachOLayoutBuilder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -235,24 +235,27 @@ Error MachOLayoutBuilder::layoutTail(uint64_t Offset) {
"Incorrect tail offset");
Offset = std::max(Offset, HeaderSize + O.Header.SizeOfCmds);

const uint64_t LinkEditAlign = Is64Bit ? 8 : 4;
Offset = alignToPowerOf2(Offset, LinkEditAlign);

// The exports trie can be in either LC_DYLD_INFO or in
// LC_DYLD_EXPORTS_TRIE, but not both.
size_t DyldInfoExportsTrieSize = 0;
size_t DyldExportsTrieSize = 0;
uint64_t DyldInfoExportsTrieRawSize = 0;
uint64_t DyldExportsTrieRawSize = 0;
for (const auto &LC : O.LoadCommands) {
switch (LC.MachOLoadCommand.load_command_data.cmd) {
case MachO::LC_DYLD_INFO:
case MachO::LC_DYLD_INFO_ONLY:
DyldInfoExportsTrieSize = O.Exports.Trie.size();
DyldInfoExportsTrieRawSize = O.Exports.Trie.size();
break;
case MachO::LC_DYLD_EXPORTS_TRIE:
DyldExportsTrieSize = O.Exports.Trie.size();
DyldExportsTrieRawSize = O.Exports.Trie.size();
break;
default:
break;
}
}
assert((DyldInfoExportsTrieSize == 0 || DyldExportsTrieSize == 0) &&
assert((DyldInfoExportsTrieRawSize == 0 || DyldExportsTrieRawSize == 0) &&
"Export trie in both LCs");

uint64_t NListSize = Is64Bit ? sizeof(MachO::nlist_64) : sizeof(MachO::nlist);
Expand All @@ -263,28 +266,43 @@ Error MachOLayoutBuilder::layoutTail(uint64_t Offset) {
// trie, chained fixups, dyld exports trie, function starts, data-in-code,
// symbol table, indirect symbol table, symbol table strings,
// dylib codesign drs, and code signature.
auto updateOffset = [&Offset](size_t Size) {
auto updateOffset = [&Offset, LinkEditAlign](uint64_t Size) {
uint64_t PreviousOffset = Offset;
Offset += Size;
return PreviousOffset;
// Match ld64 and lld-macho behavior by aligning all LINKEDIT entries to
// pointer size. This is safe because zero padding is valid for all entries.
uint64_t PaddedSize = alignToPowerOf2(Size, LinkEditAlign);
Offset += PaddedSize;
return std::make_pair(PreviousOffset, PaddedSize);
};

uint64_t StartOfRebaseInfo = updateOffset(O.Rebases.Opcodes.size());
uint64_t StartOfBindingInfo = updateOffset(O.Binds.Opcodes.size());
uint64_t StartOfWeakBindingInfo = updateOffset(O.WeakBinds.Opcodes.size());
uint64_t StartOfLazyBindingInfo = updateOffset(O.LazyBinds.Opcodes.size());
uint64_t StartOfExportTrie = updateOffset(DyldInfoExportsTrieSize);
uint64_t StartOfChainedFixups = updateOffset(O.ChainedFixups.Data.size());
uint64_t StartOfDyldExportsTrie = updateOffset(DyldExportsTrieSize);
uint64_t StartOfFunctionStarts = updateOffset(O.FunctionStarts.Data.size());
uint64_t StartOfDataInCode = updateOffset(O.DataInCode.Data.size());
uint64_t StartOfLinkerOptimizationHint =
auto [StartOfRebaseInfo, RebaseInfoSize] =
updateOffset(O.Rebases.Opcodes.size());
auto [StartOfBindingInfo, BindingInfoSize] =
updateOffset(O.Binds.Opcodes.size());
auto [StartOfWeakBindingInfo, WeakBindingInfoSize] =
updateOffset(O.WeakBinds.Opcodes.size());
auto [StartOfLazyBindingInfo, LazyBindingInfoSize] =
updateOffset(O.LazyBinds.Opcodes.size());
auto [StartOfExportTrie, ExportTrieSize] =
updateOffset(DyldInfoExportsTrieRawSize);
auto [StartOfChainedFixups, ChainedFixupsSize] =
updateOffset(O.ChainedFixups.Data.size());
auto [StartOfDyldExportsTrie, DyldExportsTrieSize] =
updateOffset(DyldExportsTrieRawSize);
auto [StartOfFunctionStarts, FunctionStartsSize] =
updateOffset(O.FunctionStarts.Data.size());
auto [StartOfDataInCode, DataInCodeSize] =
updateOffset(O.DataInCode.Data.size());
auto [StartOfLinkerOptimizationHint, LinkerOptimizationHintSize] =
updateOffset(O.LinkerOptimizationHint.Data.size());
uint64_t StartOfSymbols = updateOffset(NListSize * O.SymTable.Symbols.size());
uint64_t StartOfSymbols =
updateOffset(NListSize * O.SymTable.Symbols.size()).first;
uint64_t StartOfIndirectSymbols =
updateOffset(sizeof(uint32_t) * O.IndirectSymTable.Symbols.size());
uint64_t StartOfSymbolStrings = updateOffset(StrTableBuilder.getSize());
uint64_t StartOfDylibCodeSignDRs = updateOffset(O.DylibCodeSignDRs.Data.size());
updateOffset(sizeof(uint32_t) * O.IndirectSymTable.Symbols.size()).first;
auto [StartOfSymbolStrings, SymbolStringsSize] =
updateOffset(StrTableBuilder.getSize());
auto [StartOfDylibCodeSignDRs, DylibCodeSignDRsSize] =
updateOffset(O.DylibCodeSignDRs.Data.size());

uint64_t StartOfCodeSignature = Offset;
uint32_t CodeSignatureSize = 0;
Expand Down Expand Up @@ -343,13 +361,13 @@ Error MachOLayoutBuilder::layoutTail(uint64_t Offset) {
break;
case MachO::LC_DYLIB_CODE_SIGN_DRS:
MLC.linkedit_data_command_data.dataoff = StartOfDylibCodeSignDRs;
MLC.linkedit_data_command_data.datasize = O.DylibCodeSignDRs.Data.size();
MLC.linkedit_data_command_data.datasize = DylibCodeSignDRsSize;
break;
case MachO::LC_SYMTAB:
MLC.symtab_command_data.symoff = StartOfSymbols;
MLC.symtab_command_data.nsyms = O.SymTable.Symbols.size();
MLC.symtab_command_data.stroff = StartOfSymbolStrings;
MLC.symtab_command_data.strsize = StrTableBuilder.getSize();
MLC.symtab_command_data.strsize = SymbolStringsSize;
break;
case MachO::LC_DYSYMTAB: {
if (MLC.dysymtab_command_data.ntoc != 0 ||
Expand All @@ -368,20 +386,19 @@ Error MachOLayoutBuilder::layoutTail(uint64_t Offset) {
}
case MachO::LC_DATA_IN_CODE:
MLC.linkedit_data_command_data.dataoff = StartOfDataInCode;
MLC.linkedit_data_command_data.datasize = O.DataInCode.Data.size();
MLC.linkedit_data_command_data.datasize = DataInCodeSize;
break;
case MachO::LC_LINKER_OPTIMIZATION_HINT:
MLC.linkedit_data_command_data.dataoff = StartOfLinkerOptimizationHint;
MLC.linkedit_data_command_data.datasize =
O.LinkerOptimizationHint.Data.size();
MLC.linkedit_data_command_data.datasize = LinkerOptimizationHintSize;
break;
case MachO::LC_FUNCTION_STARTS:
MLC.linkedit_data_command_data.dataoff = StartOfFunctionStarts;
MLC.linkedit_data_command_data.datasize = O.FunctionStarts.Data.size();
MLC.linkedit_data_command_data.datasize = FunctionStartsSize;
break;
case MachO::LC_DYLD_CHAINED_FIXUPS:
MLC.linkedit_data_command_data.dataoff = StartOfChainedFixups;
MLC.linkedit_data_command_data.datasize = O.ChainedFixups.Data.size();
MLC.linkedit_data_command_data.datasize = ChainedFixupsSize;
break;
case MachO::LC_DYLD_EXPORTS_TRIE:
MLC.linkedit_data_command_data.dataoff = StartOfDyldExportsTrie;
Expand All @@ -391,19 +408,19 @@ Error MachOLayoutBuilder::layoutTail(uint64_t Offset) {
case MachO::LC_DYLD_INFO_ONLY:
MLC.dyld_info_command_data.rebase_off =
O.Rebases.Opcodes.empty() ? 0 : StartOfRebaseInfo;
MLC.dyld_info_command_data.rebase_size = O.Rebases.Opcodes.size();
MLC.dyld_info_command_data.rebase_size = RebaseInfoSize;
MLC.dyld_info_command_data.bind_off =
O.Binds.Opcodes.empty() ? 0 : StartOfBindingInfo;
MLC.dyld_info_command_data.bind_size = O.Binds.Opcodes.size();
MLC.dyld_info_command_data.bind_size = BindingInfoSize;
MLC.dyld_info_command_data.weak_bind_off =
O.WeakBinds.Opcodes.empty() ? 0 : StartOfWeakBindingInfo;
MLC.dyld_info_command_data.weak_bind_size = O.WeakBinds.Opcodes.size();
MLC.dyld_info_command_data.weak_bind_size = WeakBindingInfoSize;
MLC.dyld_info_command_data.lazy_bind_off =
O.LazyBinds.Opcodes.empty() ? 0 : StartOfLazyBindingInfo;
MLC.dyld_info_command_data.lazy_bind_size = O.LazyBinds.Opcodes.size();
MLC.dyld_info_command_data.lazy_bind_size = LazyBindingInfoSize;
MLC.dyld_info_command_data.export_off =
O.Exports.Trie.empty() ? 0 : StartOfExportTrie;
MLC.dyld_info_command_data.export_size = DyldInfoExportsTrieSize;
MLC.dyld_info_command_data.export_size = ExportTrieSize;
break;
// Note that LC_ENCRYPTION_INFO.cryptoff despite its name and the comment in
// <mach-o/loader.h> is not an offset in the binary file, instead, it is a
Expand Down
42 changes: 30 additions & 12 deletions llvm/lib/ObjCopy/MachO/MachOWriter.cpp
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Expand Up @@ -24,6 +24,12 @@ using namespace llvm;
using namespace llvm::objcopy::macho;
using namespace llvm::support::endian;

#ifndef NDEBUG
static uint64_t paddedLinkEditEntrySize(uint64_t Size, bool Is64Bit) {
return alignToPowerOf2(Size, Is64Bit ? 8 : 4);
}
#endif

size_t MachOWriter::headerSize() const {
return Is64Bit ? sizeof(MachO::mach_header_64) : sizeof(MachO::mach_header);
}
Expand Down Expand Up @@ -55,29 +61,34 @@ size_t MachOWriter::totalSize() const {
O.LoadCommands[*O.DyLdInfoCommandIndex]
.MachOLoadCommand.dyld_info_command_data;
if (DyLdInfoCommand.rebase_off) {
assert((DyLdInfoCommand.rebase_size == O.Rebases.Opcodes.size()) &&
assert((DyLdInfoCommand.rebase_size ==
paddedLinkEditEntrySize(O.Rebases.Opcodes.size(), Is64Bit)) &&
"Incorrect rebase opcodes size");
Ends.push_back(DyLdInfoCommand.rebase_off + DyLdInfoCommand.rebase_size);
}
if (DyLdInfoCommand.bind_off) {
assert((DyLdInfoCommand.bind_size == O.Binds.Opcodes.size()) &&
assert((DyLdInfoCommand.bind_size ==
paddedLinkEditEntrySize(O.Binds.Opcodes.size(), Is64Bit)) &&
"Incorrect bind opcodes size");
Ends.push_back(DyLdInfoCommand.bind_off + DyLdInfoCommand.bind_size);
}
if (DyLdInfoCommand.weak_bind_off) {
assert((DyLdInfoCommand.weak_bind_size == O.WeakBinds.Opcodes.size()) &&
assert((DyLdInfoCommand.weak_bind_size ==
paddedLinkEditEntrySize(O.WeakBinds.Opcodes.size(), Is64Bit)) &&
"Incorrect weak bind opcodes size");
Ends.push_back(DyLdInfoCommand.weak_bind_off +
DyLdInfoCommand.weak_bind_size);
}
if (DyLdInfoCommand.lazy_bind_off) {
assert((DyLdInfoCommand.lazy_bind_size == O.LazyBinds.Opcodes.size()) &&
assert((DyLdInfoCommand.lazy_bind_size ==
paddedLinkEditEntrySize(O.LazyBinds.Opcodes.size(), Is64Bit)) &&
"Incorrect lazy bind opcodes size");
Ends.push_back(DyLdInfoCommand.lazy_bind_off +
DyLdInfoCommand.lazy_bind_size);
}
if (DyLdInfoCommand.export_off) {
assert((DyLdInfoCommand.export_size == O.Exports.Trie.size()) &&
assert((DyLdInfoCommand.export_size ==
paddedLinkEditEntrySize(O.Exports.Trie.size(), Is64Bit)) &&
"Incorrect trie size");
Ends.push_back(DyLdInfoCommand.export_off + DyLdInfoCommand.export_size);
}
Expand Down Expand Up @@ -320,7 +331,8 @@ void MachOWriter::writeRebaseInfo() {
O.LoadCommands[*O.DyLdInfoCommandIndex]
.MachOLoadCommand.dyld_info_command_data;
char *Out = Buf->getBufferStart() + DyLdInfoCommand.rebase_off;
assert((DyLdInfoCommand.rebase_size == O.Rebases.Opcodes.size()) &&
assert((DyLdInfoCommand.rebase_size ==
paddedLinkEditEntrySize(O.Rebases.Opcodes.size(), Is64Bit)) &&
"Incorrect rebase opcodes size");
memcpy(Out, O.Rebases.Opcodes.data(), O.Rebases.Opcodes.size());
}
Expand All @@ -332,7 +344,8 @@ void MachOWriter::writeBindInfo() {
O.LoadCommands[*O.DyLdInfoCommandIndex]
.MachOLoadCommand.dyld_info_command_data;
char *Out = Buf->getBufferStart() + DyLdInfoCommand.bind_off;
assert((DyLdInfoCommand.bind_size == O.Binds.Opcodes.size()) &&
assert((DyLdInfoCommand.bind_size ==
paddedLinkEditEntrySize(O.Binds.Opcodes.size(), Is64Bit)) &&
"Incorrect bind opcodes size");
memcpy(Out, O.Binds.Opcodes.data(), O.Binds.Opcodes.size());
}
Expand All @@ -344,7 +357,8 @@ void MachOWriter::writeWeakBindInfo() {
O.LoadCommands[*O.DyLdInfoCommandIndex]
.MachOLoadCommand.dyld_info_command_data;
char *Out = Buf->getBufferStart() + DyLdInfoCommand.weak_bind_off;
assert((DyLdInfoCommand.weak_bind_size == O.WeakBinds.Opcodes.size()) &&
assert((DyLdInfoCommand.weak_bind_size ==
paddedLinkEditEntrySize(O.WeakBinds.Opcodes.size(), Is64Bit)) &&
"Incorrect weak bind opcodes size");
memcpy(Out, O.WeakBinds.Opcodes.data(), O.WeakBinds.Opcodes.size());
}
Expand All @@ -356,7 +370,8 @@ void MachOWriter::writeLazyBindInfo() {
O.LoadCommands[*O.DyLdInfoCommandIndex]
.MachOLoadCommand.dyld_info_command_data;
char *Out = Buf->getBufferStart() + DyLdInfoCommand.lazy_bind_off;
assert((DyLdInfoCommand.lazy_bind_size == O.LazyBinds.Opcodes.size()) &&
assert((DyLdInfoCommand.lazy_bind_size ==
paddedLinkEditEntrySize(O.LazyBinds.Opcodes.size(), Is64Bit)) &&
"Incorrect lazy bind opcodes size");
memcpy(Out, O.LazyBinds.Opcodes.data(), O.LazyBinds.Opcodes.size());
}
Expand All @@ -368,7 +383,8 @@ void MachOWriter::writeExportInfo() {
O.LoadCommands[*O.DyLdInfoCommandIndex]
.MachOLoadCommand.dyld_info_command_data;
char *Out = Buf->getBufferStart() + DyLdInfoCommand.export_off;
assert((DyLdInfoCommand.export_size == O.Exports.Trie.size()) &&
assert((DyLdInfoCommand.export_size ==
paddedLinkEditEntrySize(O.Exports.Trie.size(), Is64Bit)) &&
"Incorrect export trie size");
memcpy(Out, O.Exports.Trie.data(), O.Exports.Trie.size());
}
Expand Down Expand Up @@ -398,7 +414,8 @@ void MachOWriter::writeLinkData(std::optional<size_t> LCIndex,
const MachO::linkedit_data_command &LinkEditDataCommand =
O.LoadCommands[*LCIndex].MachOLoadCommand.linkedit_data_command_data;
char *Out = Buf->getBufferStart() + LinkEditDataCommand.dataoff;
assert((LinkEditDataCommand.datasize == LD.Data.size()) &&
assert((LinkEditDataCommand.datasize ==
paddedLinkEditEntrySize(LD.Data.size(), Is64Bit)) &&
"Incorrect data size");
memcpy(Out, LD.Data.data(), LD.Data.size());
}
Expand Down Expand Up @@ -575,7 +592,8 @@ void MachOWriter::writeExportsTrieData() {
O.LoadCommands[*O.ExportsTrieCommandIndex]
.MachOLoadCommand.linkedit_data_command_data;
char *Out = Buf->getBufferStart() + ExportsTrieCmd.dataoff;
assert((ExportsTrieCmd.datasize == O.Exports.Trie.size()) &&
assert((ExportsTrieCmd.datasize ==
paddedLinkEditEntrySize(O.Exports.Trie.size(), Is64Bit)) &&
"Incorrect export trie size");
memcpy(Out, O.Exports.Trie.data(), O.Exports.Trie.size());
}
Expand Down
9 changes: 6 additions & 3 deletions llvm/lib/ObjectYAML/MachOEmitter.cpp
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Expand Up @@ -625,9 +625,12 @@ void MachOWriter::writeStringTable(raw_ostream &OS) {
}

void MachOWriter::writeDynamicSymbolTable(raw_ostream &OS) {
for (auto Data : Obj.LinkEdit.IndirectSymbols)
OS.write(reinterpret_cast<const char *>(&Data),
sizeof(yaml::Hex32::BaseType));
for (auto Data : Obj.LinkEdit.IndirectSymbols) {
uint32_t Value = Data;
if (Obj.IsLittleEndian != sys::IsLittleEndianHost)
MachO::swapStruct(Value);
OS.write(reinterpret_cast<const char *>(&Value), sizeof(uint32_t));
}
}

void MachOWriter::writeFunctionStarts(raw_ostream &OS) {
Expand Down
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