Change split code gen to use ThreadPool
Part of D15390.
llvm-svn: 262719
diff --git a/llvm/lib/CodeGen/ParallelCG.cpp b/llvm/lib/CodeGen/ParallelCG.cpp
index d93cb91..d667ee3 100644
--- a/llvm/lib/CodeGen/ParallelCG.cpp
+++ b/llvm/lib/CodeGen/ParallelCG.cpp
@@ -19,7 +19,7 @@
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/TargetRegistry.h"
-#include "llvm/Support/thread.h"
+#include "llvm/Support/ThreadPool.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Utils/SplitModule.h"
@@ -58,40 +58,48 @@
return M;
}
- std::vector<thread> Threads;
- SplitModule(std::move(M), OSs.size(), [&](std::unique_ptr<Module> MPart) {
- // We want to clone the module in a new context to multi-thread the codegen.
- // We do it by serializing partition modules to bitcode (while still on the
- // main thread, in order to avoid data races) and spinning up new threads
- // which deserialize the partitions into separate contexts.
- // FIXME: Provide a more direct way to do this in LLVM.
- SmallVector<char, 0> BC;
- raw_svector_ostream BCOS(BC);
- WriteBitcodeToFile(MPart.get(), BCOS);
+ // Create ThreadPool in nested scope so that threads will be joined
+ // on destruction.
+ {
+ ThreadPool CodegenThreadPool(OSs.size());
+ int ThreadCount = 0;
- llvm::raw_pwrite_stream *ThreadOS = OSs[Threads.size()];
- Threads.emplace_back(
- [TheTarget, CPU, Features, Options, RM, CM, OL, FileType,
- ThreadOS](const SmallVector<char, 0> &BC) {
- LLVMContext Ctx;
- ErrorOr<std::unique_ptr<Module>> MOrErr =
- parseBitcodeFile(MemoryBufferRef(StringRef(BC.data(), BC.size()),
- "<split-module>"),
- Ctx);
- if (!MOrErr)
- report_fatal_error("Failed to read bitcode");
- std::unique_ptr<Module> MPartInCtx = std::move(MOrErr.get());
+ SplitModule(
+ std::move(M), OSs.size(),
+ [&](std::unique_ptr<Module> MPart) {
+ // We want to clone the module in a new context to multi-thread the
+ // codegen. We do it by serializing partition modules to bitcode
+ // (while still on the main thread, in order to avoid data races) and
+ // spinning up new threads which deserialize the partitions into
+ // separate contexts.
+ // FIXME: Provide a more direct way to do this in LLVM.
+ SmallVector<char, 0> BC;
+ raw_svector_ostream BCOS(BC);
+ WriteBitcodeToFile(MPart.get(), BCOS);
- codegen(MPartInCtx.get(), *ThreadOS, TheTarget, CPU, Features,
- Options, RM, CM, OL, FileType);
+ llvm::raw_pwrite_stream *ThreadOS = OSs[ThreadCount++];
+ // Enqueue the task
+ CodegenThreadPool.async(
+ [TheTarget, CPU, Features, Options, RM, CM, OL, FileType,
+ ThreadOS](const SmallVector<char, 0> &BC) {
+ LLVMContext Ctx;
+ ErrorOr<std::unique_ptr<Module>> MOrErr = parseBitcodeFile(
+ MemoryBufferRef(StringRef(BC.data(), BC.size()),
+ "<split-module>"),
+ Ctx);
+ if (!MOrErr)
+ report_fatal_error("Failed to read bitcode");
+ std::unique_ptr<Module> MPartInCtx = std::move(MOrErr.get());
+
+ codegen(MPartInCtx.get(), *ThreadOS, TheTarget, CPU, Features,
+ Options, RM, CM, OL, FileType);
+ },
+ // Pass BC using std::move to ensure that it get moved rather than
+ // copied into the thread's context.
+ std::move(BC));
},
- // Pass BC using std::move to ensure that it get moved rather than
- // copied into the thread's context.
- std::move(BC));
- }, PreserveLocals);
-
- for (thread &T : Threads)
- T.join();
+ PreserveLocals);
+ }
return {};
}