diff options
| -rw-r--r-- | lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp index a0a3df44ccd..f85dbba9d6e 100644 --- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp +++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp @@ -943,13 +943,16 @@ std::error_code MachOFileLayout::writeLoadCommands() { // If main executable, add LC_MAIN. if (_file.fileType == llvm::MachO::MH_EXECUTE) { // Build LC_MAIN load command. - entry_point_command* ep = reinterpret_cast<entry_point_command*>(lc); - ep->cmd = LC_MAIN; - ep->cmdsize = sizeof(entry_point_command); - ep->entryoff = _file.entryAddress - _seg1addr; - ep->stacksize = _file.stackSize; + // Note, using a temporary here to appease UB as we may not be aligned + // enough for a struct containing a uint64_t when emitting a 32-bit binary + entry_point_command ep; + ep.cmd = LC_MAIN; + ep.cmdsize = sizeof(entry_point_command); + ep.entryoff = _file.entryAddress - _seg1addr; + ep.stacksize = _file.stackSize; if (_swap) - swapStruct(*ep); + swapStruct(ep); + memcpy(lc, &ep, sizeof(entry_point_command)); lc += sizeof(entry_point_command); } |
