FileSystemStatCache.cpp revision 72f6130a17742e9c9078b4b60ad8f7ac2c690a3b 
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
18#if defined(_MSC_VER)
19#define S_ISDIR(s) (_S_IFDIR & s)
20#endif
21
22MemorizeStatCalls::LookupResult
23MemorizeStatCalls::getStat(const char *Path, struct stat &StatBuf) {
24  LookupResult Result = statChained(Path, StatBuf);
25
26  // Do not cache failed stats, it is easy to construct common inconsistent
27  // situations if we do, and they are not important for PCH performance (which
28  // currently only needs the stats to construct the initial FileManager
29  // entries).
30  if (Result == CacheMissing)
31    return Result;
32
33  // Cache file 'stat' results and directories with absolutely paths.
34  if (!S_ISDIR(StatBuf.st_mode) || llvm::sys::Path(Path).isAbsolute())
35    StatCalls[Path] = StatBuf;
36
37  return Result;
38}
39