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" 16 using namespace clang; 17 18 MemorizeStatCalls::LookupResult 19 MemorizeStatCalls::getStat(const char *Path, struct stat &StatBuf) { 20 LookupResult Result = statChained(Path, StatBuf); 21 22 // If the chained cache didn't know anything about the file, do the stat now 23 // so we can record the result. 24 if (Result == CacheMiss) 25 Result = ::stat(Path, &StatBuf) ? CacheHitMissing : CacheHitExists; 26 27 // Do not cache failed stats, it is easy to construct common inconsistent 28 // situations if we do, and they are not important for PCH performance (which 29 // currently only needs the stats to construct the initial FileManager 30 // entries). 31 if (Result == CacheHitMissing) 32 return Result; 33 34 // Cache file 'stat' results and directories with absolutely paths. 35 if (!S_ISDIR(StatBuf.st_mode) || llvm::sys::Path(Path).isAbsolute()) 36 StatCalls[Path] = StatBuf; 37 38 return Result; 39 } 40