1698beb542
In the past, timestamps used for `-fmodules-validate-once-per-build-session` were found to be a source of contention in the dependency scanner ([D149802](https://reviews.llvm.org/D149802), https://github.com/llvm/llvm-project/pull/112452). This PR is yet another attempt to optimize these. We now make use of the new `ModuleCache` interface to implement the in-process version in terms of atomic `std::time_t` variables rather the mtime attribute on `.timestamp` files.
68 lines
2.3 KiB
C++
68 lines
2.3 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Serialization/ModuleCache.h"
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#include "clang/Serialization/InMemoryModuleCache.h"
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#include "clang/Serialization/ModuleFile.h"
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#include "llvm/Support/FileSystem.h"
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#include "llvm/Support/LockFileManager.h"
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#include "llvm/Support/Path.h"
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using namespace clang;
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namespace {
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class CrossProcessModuleCache : public ModuleCache {
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InMemoryModuleCache InMemory;
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public:
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void prepareForGetLock(StringRef ModuleFilename) override {
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// FIXME: Do this in LockFileManager and only if the directory doesn't
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// exist.
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StringRef Dir = llvm::sys::path::parent_path(ModuleFilename);
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llvm::sys::fs::create_directories(Dir);
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}
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std::unique_ptr<llvm::AdvisoryLock>
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getLock(StringRef ModuleFilename) override {
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return std::make_unique<llvm::LockFileManager>(ModuleFilename);
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}
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std::time_t getModuleTimestamp(StringRef ModuleFilename) override {
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std::string TimestampFilename =
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serialization::ModuleFile::getTimestampFilename(ModuleFilename);
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llvm::sys::fs::file_status Status;
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if (llvm::sys::fs::status(ModuleFilename, Status) != std::error_code{})
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return 0;
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return llvm::sys::toTimeT(Status.getLastModificationTime());
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}
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void updateModuleTimestamp(StringRef ModuleFilename) override {
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// Overwrite the timestamp file contents so that file's mtime changes.
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std::error_code EC;
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llvm::raw_fd_ostream OS(
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serialization::ModuleFile::getTimestampFilename(ModuleFilename), EC,
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llvm::sys::fs::OF_TextWithCRLF);
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if (EC)
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return;
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OS << "Timestamp file\n";
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OS.close();
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OS.clear_error(); // Avoid triggering a fatal error.
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}
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InMemoryModuleCache &getInMemoryModuleCache() override { return InMemory; }
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const InMemoryModuleCache &getInMemoryModuleCache() const override {
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return InMemory;
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}
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};
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} // namespace
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IntrusiveRefCntPtr<ModuleCache> clang::createCrossProcessModuleCache() {
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return llvm::makeIntrusiveRefCnt<CrossProcessModuleCache>();
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}
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