<rdar://problem/13434605> Periodically prune the module cache so that it does not grow forever.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177918 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index f83c870..2a35ca0 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -44,6 +44,8 @@
#include "llvm/Support/Timer.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/system_error.h"
+#include <sys/stat.h>
+#include <sys/time.h>
using namespace clang;
@@ -996,6 +998,97 @@
<< false;
}
+/// \brief Write a new timestamp file with the given path.
+static void writeTimestampFile(StringRef TimestampFile) {
+ std::string ErrorInfo;
+ llvm::raw_fd_ostream Out(TimestampFile.str().c_str(), ErrorInfo,
+ llvm::raw_fd_ostream::F_Binary);
+}
+
+/// \brief Prune the module cache of modules that haven't been accessed in
+/// a long time.
+static void pruneModuleCache(const HeaderSearchOptions &HSOpts) {
+ struct stat StatBuf;
+ llvm::SmallString<128> TimestampFile;
+ TimestampFile = HSOpts.ModuleCachePath;
+ llvm::sys::path::append(TimestampFile, "modules.timestamp");
+
+ // Try to stat() the timestamp file.
+ if (::stat(TimestampFile.c_str(), &StatBuf)) {
+ // If the timestamp file wasn't there, create one now.
+ if (errno == ENOENT) {
+ writeTimestampFile(TimestampFile);
+ }
+ return;
+ }
+
+ // Check whether the time stamp is older than our pruning interval.
+ // If not, do nothing.
+ time_t TimeStampModTime = StatBuf.st_mtime;
+ time_t CurrentTime = time(0);
+ if (CurrentTime - TimeStampModTime <= HSOpts.ModuleCachePruneInterval) {
+ return;
+ }
+
+ // Write a new timestamp file so that nobody else attempts to prune.
+ // There is a benign race condition here, if two Clang instances happen to
+ // notice at the same time that the timestamp is out-of-date.
+ writeTimestampFile(TimestampFile);
+
+ // Walk the entire module cache, looking for unused module files and module
+ // indices.
+ llvm::error_code EC;
+ SmallString<128> ModuleCachePathNative;
+ llvm::sys::path::native(HSOpts.ModuleCachePath, ModuleCachePathNative);
+ for (llvm::sys::fs::directory_iterator
+ Dir(ModuleCachePathNative.str(), EC), DirEnd;
+ Dir != DirEnd && !EC; Dir.increment(EC)) {
+ // If we don't have a directory, there's nothing to look into.
+ bool IsDirectory;
+ if (llvm::sys::fs::is_directory(Dir->path(), IsDirectory) || !IsDirectory)
+ continue;
+
+ // Walk all of the files within this directory.
+ bool RemovedAllFiles = true;
+ for (llvm::sys::fs::directory_iterator File(Dir->path(), EC), FileEnd;
+ File != FileEnd && !EC; File.increment(EC)) {
+ // We only care about module and global module index files.
+ if (llvm::sys::path::extension(File->path()) != ".pcm" &&
+ llvm::sys::path::filename(File->path()) != "modules.idx") {
+ RemovedAllFiles = false;
+ continue;
+ }
+
+ // Look at this file. If we can't stat it, there's nothing interesting
+ // there.
+ if (::stat(File->path().c_str(), &StatBuf)) {
+ RemovedAllFiles = false;
+ continue;
+ }
+
+ // If the file has been used recently enough, leave it there.
+ time_t FileAccessTime = StatBuf.st_atime;
+ if (CurrentTime - FileAccessTime <= HSOpts.ModuleCachePruneAfter) {
+ RemovedAllFiles = false;;
+ continue;
+ }
+
+ // Remove the file.
+ bool Existed;
+ if (llvm::sys::fs::remove(File->path(), Existed) || !Existed) {
+ RemovedAllFiles = false;
+ }
+ }
+
+ // If we removed all of the files in the directory, remove the directory
+ // itself.
+ if (RemovedAllFiles) {
+ bool Existed;
+ llvm::sys::fs::remove(Dir->path(), Existed);
+ }
+ }
+}
+
ModuleLoadResult
CompilerInstance::loadModule(SourceLocation ImportLoc,
ModuleIdPath Path,
@@ -1042,6 +1135,14 @@
if (!hasASTContext())
createASTContext();
+ // If we're not recursively building a module, check whether we
+ // need to prune the module cache.
+ if (getSourceManager().getModuleBuildStack().empty() &&
+ getHeaderSearchOpts().ModuleCachePruneInterval > 0 &&
+ getHeaderSearchOpts().ModuleCachePruneAfter > 0) {
+ pruneModuleCache(getHeaderSearchOpts());
+ }
+
std::string Sysroot = getHeaderSearchOpts().Sysroot;
const PreprocessorOptions &PPOpts = getPreprocessorOpts();
ModuleManager = new ASTReader(getPreprocessor(), *Context,