[lld] Reject --read-workers when lld is built without thread support

[DavidSpickett]

Also expand the #ifdef to remove unused code in this configuration. As suggested in #147134 (comment).

I have also:

• Expanded the error message to explain why it's not allowed.
• Added a test for the error.
• Marked the original test as unsupported when threads are disabled.

Fixes issues we have had on Armv8 with threading disabled where this test would crash every so often.

This change will hopefully be superseded by #157917, but that has been in review a long time and I want to make the bot stable again.

I could just disable the test, but I'd like lld to function properly in general in the meantime too.

Co-authored-by: John Holdsworth github@johnholdsworth.com

[llvmbot]

@llvm/pr-subscribers-lld

@llvm/pr-subscribers-lld-macho

Author: David Spickett (DavidSpickett)

Changes

Also expand the #ifdef to remove unused code in this configuration. As suggested in #147134 (comment).

I have also:

• Expanded the error message to explain why it's not allowed.
• Added a test for the error.
• Marked the original test as unsupported when threads are disabled.

Fixes issues we have had on Armv8 with threading disabled where this test would crash every so often.

This change will hopefully be superseded by #157917, but that has been in review a long time and I want to make the bot stable again.

I could just disable the test, but I'd like lld to function properly in general in the meantime too.

Co-authored-by: John Holdsworth <github@johnholdsworth.com>

---

Full diff: https://github.com/llvm/llvm-project/pull/163925.diff

6 Files Affected:

• (modified) lld/MachO/Driver.cpp (+9-2)
• (modified) lld/test/CMakeLists.txt (+1)
• (added) lld/test/MachO/read-workers-no-thread-support.s (+10)
• (modified) lld/test/MachO/read-workers.s (+1-1)
• (modified) lld/test/lit.cfg.py (+3)
• (modified) lld/test/lit.site.cfg.py.in (+1)

diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp index bfd35aef72b58..9b67db9fa55cf 100644 --- a/lld/MachO/Driver.cpp +++ b/lld/MachO/Driver.cpp @@ -291,6 +291,7 @@ struct DeferredFile { }; using DeferredFiles = std::vector<DeferredFile>; +#if LLVM_ENABLE_THREADS class SerialBackgroundQueue { std::deque<std::function<void()>> queue; std::thread *running; @@ -359,7 +360,6 @@ void multiThreadedPageInBackground(DeferredFiles &deferred) { (void)t; } }; -#if LLVM_ENABLE_THREADS { // Create scope for waiting for the taskGroup std::atomic_size_t index = 0; llvm::parallel::TaskGroup taskGroup; @@ -373,7 +373,6 @@ void multiThreadedPageInBackground(DeferredFiles &deferred) { } }); } -#endif #ifndef NDEBUG auto dt = high_resolution_clock::now() - t0; if (Process::GetEnv("LLD_MULTI_THREAD_PAGE")) @@ -390,6 +389,7 @@ static void multiThreadedPageIn(const DeferredFiles &deferred) { multiThreadedPageInBackground(files); }); } +#endif static InputFile *processFile(std::optional<MemoryBufferRef> buffer, DeferredFiles *archiveContents, StringRef path, @@ -1430,6 +1430,7 @@ static void createFiles(const InputArgList &args) { } } +#if LLVM_ENABLE_THREADS if (config->readWorkers) { multiThreadedPageIn(deferredFiles); @@ -1447,6 +1448,7 @@ static void createFiles(const InputArgList &args) { for (auto *archive : archives) archive->addLazySymbols(); } +#endif } static void gatherInputSections() { @@ -1834,6 +1836,7 @@ bool link(ArrayRef<const char *> argsArr, llvm::raw_ostream &stdoutOS, } if (auto *arg = args.getLastArg(OPT_read_workers)) { +#if LLVM_ENABLE_THREADS StringRef v(arg->getValue()); unsigned workers = 0; if (!llvm::to_integer(v, workers, 0)) @@ -1841,6 +1844,10 @@ bool link(ArrayRef<const char *> argsArr, llvm::raw_ostream &stdoutOS, ": expected a non-negative integer, but got '" + arg->getValue() + "'"); config->readWorkers = workers; +#else + error(arg->getSpelling() + + ": option unavailable because lld was not built with thread support"); +#endif } if (auto *arg = args.getLastArg(OPT_threads_eq)) { StringRef v(arg->getValue()); diff --git a/lld/test/CMakeLists.txt b/lld/test/CMakeLists.txt index abc8ea75da180..1bd3ad7e1765b 100644 --- a/lld/test/CMakeLists.txt +++ b/lld/test/CMakeLists.txt @@ -1,5 +1,6 @@ llvm_canonicalize_cmake_booleans( ENABLE_BACKTRACES + LLVM_ENABLE_THREADS LLVM_ENABLE_ZLIB LLVM_ENABLE_ZSTD LLVM_ENABLE_LIBXML2 diff --git a/lld/test/MachO/read-workers-no-thread-support.s b/lld/test/MachO/read-workers-no-thread-support.s new file mode 100644 index 0000000000000..16256be42af73 --- /dev/null +++ b/lld/test/MachO/read-workers-no-thread-support.s @@ -0,0 +1,10 @@ +# REQUIRES: x86 && !thread_support +# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o + +# RUN: not %lld --read-workers=1 %t.o -o /dev/null + +# CHECK: error: --read-workers=: option unavailable because lld was built without thread support + +.globl _main +_main: + ret diff --git a/lld/test/MachO/read-workers.s b/lld/test/MachO/read-workers.s index 6f0ea4d894408..4d2f88c2a757c 100644 --- a/lld/test/MachO/read-workers.s +++ b/lld/test/MachO/read-workers.s @@ -1,4 +1,4 @@ -# REQUIRES: x86 +# REQUIRES: x86 && thread_support # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o ## A non-negative integer is allowed. diff --git a/lld/test/lit.cfg.py b/lld/test/lit.cfg.py index 336945729954e..906afc52a0d09 100644 --- a/lld/test/lit.cfg.py +++ b/lld/test/lit.cfg.py @@ -182,3 +182,6 @@ # ELF tests expect the default target for ld.lld to be ELF. if config.ld_lld_default_mingw: config.excludes.append("ELF") + +if config.enable_threads: + config.available_features.add("thread_support") \ No newline at end of file diff --git a/lld/test/lit.site.cfg.py.in b/lld/test/lit.site.cfg.py.in index bb99976005543..703d3b1fd5337 100644 --- a/lld/test/lit.site.cfg.py.in +++ b/lld/test/lit.site.cfg.py.in @@ -26,6 +26,7 @@ config.ld_lld_default_mingw = @LLD_DEFAULT_LD_LLD_IS_MINGW@ config.build_examples = @LLVM_BUILD_EXAMPLES@ config.has_plugins = @LLVM_ENABLE_PLUGINS@ config.linked_bye_extension = @LLVM_BYE_LINK_INTO_TOOLS@ +config.enable_threads = @LLVM_ENABLE_THREADS@ import lit.llvm lit.llvm.initialize(lit_config, config) 

[llvm-ci]

LLVM Buildbot has detected a new failure on builder ppc64le-lld-multistage-test running on ppc64le-lld-multistage-test while building lld at step 12 "build-stage2-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/168/builds/16688

Here is the relevant piece of the build log for the reference

Step 12 (build-stage2-unified-tree) failure: build (failure) (timed out) ... 1139.171 [57/10/6679] Linking CXX executable bin/llvm-isel-fuzzer 1139.190 [57/9/6680] Linking CXX executable bin/dsymutil 1139.425 [57/8/6681] Linking CXX executable bin/clang-linker-wrapper 1139.560 [57/7/6682] Linking CXX executable bin/llvm-split 1139.563 [57/6/6683] Linking CXX executable unittests/MI/MITests 1140.056 [57/5/6684] Linking CXX executable tools/lld/unittests/AsLibAll/LLDAsLibAllTests 1140.072 [57/4/6685] Linking CXX executable bin/opt 1140.331 [57/3/6686] Linking CXX executable bin/lld 1157.122 [57/2/6687] Building CXX object tools/bugpoint-passes/CMakeFiles/BugpointPasses.dir/TestPasses.cpp.o 1157.678 [56/2/6688] Linking CXX shared module lib/BugpointPasses.so command timed out: 1200 seconds without output running [b'ninja'], attempting to kill process killed by signal 9 program finished with exit code -1 elapsedTime=2358.485816