FileSystemStatCache.cpp revision d6f611198089b78e32d3a15fe8bc986204aee1aa 
1//===--- FileSystemStatCache.cpp - Caching for 'stat' calls ---------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file defines the FileSystemStatCache interface.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Basic/FileSystemStatCache.h"
15#include "llvm/System/Path.h"
16using namespace clang;
17
18MemorizeStatCalls::LookupResult
19MemorizeStatCalls::getStat(const char *Path, struct stat &StatBuf) {
20  LookupResult Result = statChained(Path, StatBuf);
21
22  // Do not cache failed stats, it is easy to construct common inconsistent
23  // situations if we do, and they are not important for PCH performance (which
24  // currently only needs the stats to construct the initial FileManager
25  // entries).
26  if (Result == CacheMissing)
27    return Result;
28
29  // Cache file 'stat' results and directories with absolutely paths.
30  if (!S_ISDIR(StatBuf.st_mode) || llvm::sys::Path(Path).isAbsolute())
31    StatCalls[Path] = StatBuf;
32
33  return Result;
34}
35