154 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "clang/Serialization/ModuleCache.h"10 11#include "clang/Serialization/InMemoryModuleCache.h"12#include "clang/Serialization/ModuleFile.h"13#include "llvm/Support/FileSystem.h"14#include "llvm/Support/LockFileManager.h"15#include "llvm/Support/Path.h"16 17using namespace clang;18 19/// Write a new timestamp file with the given path.20static void writeTimestampFile(StringRef TimestampFile) {21 std::error_code EC;22 llvm::raw_fd_ostream Out(TimestampFile.str(), EC, llvm::sys::fs::OF_None);23}24 25void clang::maybePruneImpl(StringRef Path, time_t PruneInterval,26 time_t PruneAfter) {27 if (PruneInterval <= 0 || PruneAfter <= 0)28 return;29 30 llvm::SmallString<128> TimestampFile(Path);31 llvm::sys::path::append(TimestampFile, "modules.timestamp");32 33 // Try to stat() the timestamp file.34 llvm::sys::fs::file_status StatBuf;35 if (std::error_code EC = llvm::sys::fs::status(TimestampFile, StatBuf)) {36 // If the timestamp file wasn't there, create one now.37 if (EC == std::errc::no_such_file_or_directory)38 writeTimestampFile(TimestampFile);39 return;40 }41 42 // Check whether the time stamp is older than our pruning interval.43 // If not, do nothing.44 time_t TimestampModTime =45 llvm::sys::toTimeT(StatBuf.getLastModificationTime());46 time_t CurrentTime = time(nullptr);47 if (CurrentTime - TimestampModTime <= PruneInterval)48 return;49 50 // Write a new timestamp file so that nobody else attempts to prune.51 // There is a benign race condition here, if two Clang instances happen to52 // notice at the same time that the timestamp is out-of-date.53 writeTimestampFile(TimestampFile);54 55 // Walk the entire module cache, looking for unused module files and module56 // indices.57 std::error_code EC;58 for (llvm::sys::fs::directory_iterator Dir(Path, EC), DirEnd;59 Dir != DirEnd && !EC; Dir.increment(EC)) {60 // If we don't have a directory, there's nothing to look into.61 if (!llvm::sys::fs::is_directory(Dir->path()))62 continue;63 64 // Walk all the files within this directory.65 for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;66 File != FileEnd && !EC; File.increment(EC)) {67 // We only care about module and global module index files.68 StringRef Extension = llvm::sys::path::extension(File->path());69 if (Extension != ".pcm" && Extension != ".timestamp" &&70 llvm::sys::path::filename(File->path()) != "modules.idx")71 continue;72 73 // Look at this file. If we can't stat it, there's nothing interesting74 // there.75 if (llvm::sys::fs::status(File->path(), StatBuf))76 continue;77 78 // If the file has been used recently enough, leave it there.79 time_t FileAccessTime = llvm::sys::toTimeT(StatBuf.getLastAccessedTime());80 if (CurrentTime - FileAccessTime <= PruneAfter)81 continue;82 83 // Remove the file.84 llvm::sys::fs::remove(File->path());85 86 // Remove the timestamp file.87 std::string TimpestampFilename = File->path() + ".timestamp";88 llvm::sys::fs::remove(TimpestampFilename);89 }90 91 // If we removed all the files in the directory, remove the directory92 // itself.93 if (llvm::sys::fs::directory_iterator(Dir->path(), EC) ==94 llvm::sys::fs::directory_iterator() &&95 !EC)96 llvm::sys::fs::remove(Dir->path());97 }98}99 100namespace {101class CrossProcessModuleCache : public ModuleCache {102 InMemoryModuleCache InMemory;103 104public:105 void prepareForGetLock(StringRef ModuleFilename) override {106 // FIXME: Do this in LockFileManager and only if the directory doesn't107 // exist.108 StringRef Dir = llvm::sys::path::parent_path(ModuleFilename);109 llvm::sys::fs::create_directories(Dir);110 }111 112 std::unique_ptr<llvm::AdvisoryLock>113 getLock(StringRef ModuleFilename) override {114 return std::make_unique<llvm::LockFileManager>(ModuleFilename);115 }116 117 std::time_t getModuleTimestamp(StringRef ModuleFilename) override {118 std::string TimestampFilename =119 serialization::ModuleFile::getTimestampFilename(ModuleFilename);120 llvm::sys::fs::file_status Status;121 if (llvm::sys::fs::status(TimestampFilename, Status) != std::error_code{})122 return 0;123 return llvm::sys::toTimeT(Status.getLastModificationTime());124 }125 126 void updateModuleTimestamp(StringRef ModuleFilename) override {127 // Overwrite the timestamp file contents so that file's mtime changes.128 std::error_code EC;129 llvm::raw_fd_ostream OS(130 serialization::ModuleFile::getTimestampFilename(ModuleFilename), EC,131 llvm::sys::fs::OF_TextWithCRLF);132 if (EC)133 return;134 OS << "Timestamp file\n";135 OS.close();136 OS.clear_error(); // Avoid triggering a fatal error.137 }138 139 void maybePrune(StringRef Path, time_t PruneInterval,140 time_t PruneAfter) override {141 maybePruneImpl(Path, PruneInterval, PruneAfter);142 }143 144 InMemoryModuleCache &getInMemoryModuleCache() override { return InMemory; }145 const InMemoryModuleCache &getInMemoryModuleCache() const override {146 return InMemory;147 }148};149} // namespace150 151IntrusiveRefCntPtr<ModuleCache> clang::createCrossProcessModuleCache() {152 return llvm::makeIntrusiveRefCnt<CrossProcessModuleCache>();153}154