replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Add lightweight shim "clang::StatSysCallCache" that caches 'stat' system calls 

for use by FileManager. FileManager now takes a StatSysCallCache* in its
constructor (which defaults to NULL). This will be used for evaluating whether
or not caching 'stat' system calls in PTH is a performance win. This shim adds
no observable performance impact in the case where the 'StatSysCallCache*' is
null.

llvm-svn: 64345
This commit is contained in:
Ted Kremenek 2009-02-12 00:39:05 +00:00
parent 6752502b81
commit c8b740eade
2 changed files with 27 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
clang/include/clang/Basic/FileManager.h
View File

@ -22,6 +22,7 @@
#include <string>
// FIXME: Enhance libsystem to support inode and other fields in stat.
#include <sys/types.h>
#include <sys/stat.h>
namespace clang {
class FileManager;
@ -68,6 +69,14 @@ public:
}
};
// FIXME: This is a lightweight shim that is used by FileManager to cache
// 'stat' system calls. We will use it with PTH to identify if caching
// stat calls in PTH files is a performance win.
class StatSysCallCache {
public:
virtual ~StatSysCallCache() {}
virtual int stat(const char *path, struct stat *buf) = 0;
};
/// FileManager - Implements support for file system lookup, file system
/// caching, and directory search management. This also handles more advanced
@ -97,8 +106,15 @@ class FileManager {
// Statistics.
unsigned NumDirLookups, NumFileLookups;
unsigned NumDirCacheMisses, NumFileCacheMisses;
// Caching.
StatSysCallCache *StatCache;
int stat_cached(const char* path, struct stat* buf) {
return StatCache ? StatCache->stat(path, buf) : stat(path, buf);
}
public:
FileManager();
FileManager(StatSysCallCache *statCache = 0);
~FileManager();
/// getDirectory - Lookup, cache, and verify the specified directory. This

18
clang/lib/Basic/FileManager.cpp
View File

@ -29,7 +29,7 @@ using namespace clang;
#include <sys/stat.h>
#if defined(_MSC_VER)
#define S_ISDIR(s) (_S_IFDIR & s)
#defisstne S_ISDIR(s) (_S_IFDIR & s)
#endif
/// NON_EXISTENT_DIR - A special value distinct from null that is used to
@ -134,10 +134,11 @@ public:
// Common logic.
//===----------------------------------------------------------------------===//
FileManager::FileManager() : UniqueDirs(*new UniqueDirContainer),
UniqueFiles(*new UniqueFileContainer),
DirEntries(64), FileEntries(64), NextFileUID(0)
{
FileManager::FileManager(StatSysCallCache* statCache)
: UniqueDirs(*new UniqueDirContainer),
UniqueFiles(*new UniqueFileContainer),
DirEntries(64), FileEntries(64), NextFileUID(0),
StatCache(statCache) {
NumDirLookups = NumFileLookups = 0;
NumDirCacheMisses = NumFileCacheMisses = 0;
}
@ -145,6 +146,7 @@ FileManager::FileManager() : UniqueDirs(*new UniqueDirContainer),
FileManager::~FileManager() {
delete &UniqueDirs;
delete &UniqueFiles;
delete StatCache;
}
@ -173,7 +175,7 @@ const DirectoryEntry *FileManager::getDirectory(const char *NameStart,
// Check to see if the directory exists.
struct stat StatBuf;
if (stat(InterndDirName, &StatBuf) || // Error stat'ing.
if (stat_cached(InterndDirName, &StatBuf) || // Error stat'ing.
!S_ISDIR(StatBuf.st_mode)) // Not a directory?
return 0;
@ -246,8 +248,8 @@ const FileEntry *FileManager::getFile(const char *NameStart,
// Nope, there isn't. Check to see if the file exists.
struct stat StatBuf;
//llvm::cerr << "STATING: " << Filename;
if (stat(InterndFileName, &StatBuf) || // Error stat'ing.
S_ISDIR(StatBuf.st_mode)) { // A directory?
if (stat_cached(InterndFileName, &StatBuf) || // Error stat'ing.
S_ISDIR(StatBuf.st_mode)) { // A directory?
// If this file doesn't exist, we leave a null in FileEntries for this path.
//llvm::cerr << ": Not existing\n";
return 0;