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Extend stat query APIs to explicitly specify if the query is for

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a file or directory, allowing just a stat call if a file descriptor
is not needed.

Doing just 'stat' is faster than 'open/fstat/close'.
This has the effect of cutting down system time for validating the input files of a PCH.

llvm-svn: 169831
This commit is contained in:
Argyrios Kyrtzidis
2012-12-11 07:48:23 +00:00
parent 53c3877f94
commit 3b7793797f
7 changed files with 35 additions and 36 deletions
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20
clang/lib/Basic/FileSystemStatCache.cpp
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@@ -34,21 +34,23 @@ void FileSystemStatCache::anchor() { }
/// path, using the cache to accelerate it if possible. This returns true if
/// the path does not exist or false if it exists.
///
/// If FileDescriptor is non-null, then this lookup should only return success
/// for files (not directories). If it is null this lookup should only return
/// If isFile is true, then this lookup should only return success for files
/// (not directories). If it is false this lookup should only return
/// success for directories (not files). On a successful file lookup, the
/// implementation can optionally fill in FileDescriptor with a valid
/// descriptor and the client guarantees that it will close it.
bool FileSystemStatCache::get(const char *Path, struct stat &StatBuf,
int *FileDescriptor, FileSystemStatCache *Cache) {
bool isFile, int *FileDescriptor,
FileSystemStatCache *Cache) {
LookupResult R;
bool isForDir = FileDescriptor == 0;
bool isForDir = !isFile;
// If we have a cache, use it to resolve the stat query.
if (Cache)
R = Cache->getStat(Path, StatBuf, FileDescriptor);
else if (isForDir) {
// If this is a directory and we have no cache, just go to the file system.
R = Cache->getStat(Path, StatBuf, isFile, FileDescriptor);
else if (isForDir || !FileDescriptor) {
// If this is a directory or a file descriptor is not needed and we have
// no cache, just go to the file system.
R = ::stat(Path, &StatBuf) != 0 ? CacheMissing : CacheExists;
} else {
// Otherwise, we have to go to the filesystem. We can always just use
@@ -104,8 +106,8 @@ bool FileSystemStatCache::get(const char *Path, struct stat &StatBuf,
MemorizeStatCalls::LookupResult
MemorizeStatCalls::getStat(const char *Path, struct stat &StatBuf,
int *FileDescriptor) {
LookupResult Result = statChained(Path, StatBuf, FileDescriptor);
bool isFile, int *FileDescriptor) {
LookupResult Result = statChained(Path, StatBuf, isFile, FileDescriptor);
// Do not cache failed stats, it is easy to construct common inconsistent
// situations if we do, and they are not important for PCH performance (which