Index: lld/MachO/Writer.cpp =================================================================== --- lld/MachO/Writer.cpp +++ lld/MachO/Writer.cpp @@ -1075,7 +1075,8 @@ // Round-up integer division size_t chunkSize = (data.size() + chunkCount - 1) / chunkCount; std::vector> chunks = split(data, chunkSize); - std::vector hashes(chunks.size()); + // Leave one slot for filename + std::vector hashes(chunks.size() + 1); SmallVector> threadFutures; threadFutures.reserve(chunks.size()); for (size_t i = 0; i < chunks.size(); ++i) @@ -1083,7 +1084,9 @@ [&](size_t j) { hashes[j] = xxHash64(chunks[j]); }, i)); for (std::shared_future &future : threadFutures) future.wait(); - + // Append the output filename so that identical binaries with different names + // don't get the same UUID. + hashes[chunks.size()] = xxHash64(sys::path::filename(config->finalOutput)); uint64_t digest = xxHash64({reinterpret_cast(hashes.data()), hashes.size() * sizeof(uint64_t)}); uuidCommand->writeUuid(digest); Index: lld/test/MachO/uuid.s =================================================================== --- lld/test/MachO/uuid.s +++ lld/test/MachO/uuid.s @@ -1,8 +1,15 @@ # REQUIRES: x86 -# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o -# RUN: %lld -lSystem %t.o -o %t -# RUN: llvm-dwarfdump --uuid %t | FileCheck %s -# CHECK: 4C4C44{{([[:xdigit:]]{2})}}-5555-{{([[:xdigit:]]{4})}}-A1{{([[:xdigit:]]{2})}}-{{([[:xdigit:]]{12})}} (x86_64) +# RUN: rm -rf %t && mkdir -p %t +# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t/test.o +# RUN: %lld -lSystem %t/test.o -o %t/a +# RUN: %lld -lSystem %t/test.o -o %t/b +# RUN: llvm-dwarfdump --uuid %t/a | awk '{print $2}' > %t/uuida +# RUN: llvm-dwarfdump --uuid %t/b | awk '{print $2}' > %t/uuidb +# RUN: FileCheck %s < %t/uuida +# RUN: FileCheck %s < %t/uuidb +# RUN: not cmp %t/uuida %t/uuidb + +# CHECK: 4C4C44{{([[:xdigit:]]{2})}}-5555-{{([[:xdigit:]]{4})}}-A1{{([[:xdigit:]]{2})}}-{{([[:xdigit:]]{12})}} .globl _main _main: