https://github.com/wenju-he created https://github.com/llvm/llvm-project/pull/224548
AOT-compile all split modules in a thread pool instead of one at a time, cutting AOT wall time when there are multiple split modules. >From 1ce31dddedbe12c8cad2cfc32835c09b009d88a5 Mon Sep 17 00:00:00 2001 From: Wenju He <[email protected]> Date: Fri, 18 Sep 2026 09:49:21 +0200 Subject: [PATCH] [clang-sycl-linker] AOT-compile split modules concurrently AOT-compile all split modules in a thread pool instead of one at a time, cutting AOT wall time when there are multiple split modules. Co-Authored-By: Claude Sonnet 5 <[email protected]> --- .../clang-sycl-linker/ClangSYCLLinker.cpp | 59 +++++++++++++++++-- 1 file changed, 53 insertions(+), 6 deletions(-) diff --git a/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp b/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp index 70afc6d6c4cea..c1b964d58c204 100644 --- a/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp +++ b/clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp @@ -52,6 +52,7 @@ #include "llvm/Support/Signals.h" #include "llvm/Support/StringSaver.h" #include "llvm/Support/TargetSelect.h" +#include "llvm/Support/ThreadPool.h" #include "llvm/Support/TimeProfiler.h" #include "llvm/Support/WithColor.h" #include "llvm/Target/TargetMachine.h" @@ -924,6 +925,54 @@ static bool canSkipModuleSplit(IRSplitMode Mode, const Module &M, }); } +/// AOT-compiles every already-produced image in \p SplitModules concurrently +/// and swaps each module's path to point at the compiled object. +static Error aotCompileSplitModules(SmallVectorImpl<SplitModule> &SplitModules, + const ArgList &Args, StringRef OutputFile) { + // Each worker thread writes only its own index, so this is race-free. + SmallVector<std::string, 0> AOTFiles(SplitModules.size()); + // std::optional, not Error: pre-filled Error::success() move-assigned + // from a worker thread would abort on the unchecked-value assert. + SmallVector<std::optional<Error>, 0> AOTErrors(SplitModules.size()); + for (size_t I = 0, E = SplitModules.size(); I != E; ++I) { + SmallString<64> Prefix; + (sys::path::filename(OutputFile).rsplit('.').first + "_" + Twine(I)) + .toVector(Prefix); + Expected<StringRef> AOTFileOrErr = createTempFile(Args, Prefix, "out"); + if (!AOTFileOrErr) + return AOTFileOrErr.takeError(); + AOTFiles[I] = std::string(*AOTFileOrErr); + } + { + DefaultThreadPool AOTPool(llvm::heavyweight_hardware_concurrency()); + for (size_t I = 0, E = SplitModules.size(); I != E; ++I) + AOTPool.async( + [&](size_t I) { + AOTErrors[I].emplace(runAOTCompile(SplitModules[I].ModuleFilePath, + AOTFiles[I], Args)); + }, + I); + AOTPool.wait(); + } + // Every Error must be checked once, so visit all before returning + // instead of stopping at the first failure. + Error FirstErr = Error::success(); + for (std::optional<Error> &Err : AOTErrors) { + if (!*Err) + continue; + if (FirstErr) + consumeError(std::move(*Err)); + else + FirstErr = std::move(*Err); + } + if (FirstErr) + return FirstErr; + + for (size_t I = 0, E = AOTFiles.size(); I != E; ++I) + SplitModules[I].ModuleFilePath = AOTFiles[I]; + return Error::success(); +} + /// Performs the following steps: /// 1. Link all input bitcode files together with library files. /// 2. Optionally split the linked module according to the requested @@ -1000,14 +1049,12 @@ static Error runSYCLLink(ArrayRef<std::unique_ptr<MemoryBuffer>> Inputs, } SplitModules[I].ModuleFilePath = CodeGenFile; - if (IsAOTCompileNeeded) { - std::string AOTFile = (Stem + "_" + Twine(I) + ".out").str(); - if (Error Err = runAOTCompile(CodeGenFile, AOTFile, Args)) - return Err; - SplitModules[I].ModuleFilePath = AOTFile; - } } + if (IsAOTCompileNeeded) + if (Error Err = aotCompileSplitModules(SplitModules, Args, OutputFile)) + return Err; + // Collect all images to be packed into a single OffloadBinary. SmallVector<OffloadingImage> Images; for (SplitModule &SI : SplitModules) { _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
