1 //===--- FileManager.cpp - File System Probing and Caching ----------------===// 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 implements the FileManager interface. 11 // 12 //===----------------------------------------------------------------------===// 13 // 14 // TODO: This should index all interesting directories with dirent calls. 15 // getdirentries ? 16 // opendir/readdir_r/closedir ? 17 // 18 //===----------------------------------------------------------------------===// 19 20 #include "clang/Basic/FileManager.h" 21 #include "clang/Basic/FileSystemStatCache.h" 22 #include "llvm/ADT/SmallString.h" 23 #include "llvm/Config/llvm-config.h" 24 #include "llvm/ADT/STLExtras.h" 25 #include "llvm/Support/FileSystem.h" 26 #include "llvm/Support/MemoryBuffer.h" 27 #include "llvm/Support/Path.h" 28 #include "llvm/Support/raw_ostream.h" 29 #include <map> 30 #include <set> 31 #include <string> 32 #include <system_error> 33 34 using namespace clang; 35 36 /// NON_EXISTENT_DIR - A special value distinct from null that is used to 37 /// represent a dir name that doesn't exist on the disk. 38 #define NON_EXISTENT_DIR reinterpret_cast<DirectoryEntry*>((intptr_t)-1) 39 40 /// NON_EXISTENT_FILE - A special value distinct from null that is used to 41 /// represent a filename that doesn't exist on the disk. 42 #define NON_EXISTENT_FILE reinterpret_cast<FileEntry*>((intptr_t)-1) 43 44 //===----------------------------------------------------------------------===// 45 // Common logic. 46 //===----------------------------------------------------------------------===// 47 48 FileManager::FileManager(const FileSystemOptions &FSO, 49 IntrusiveRefCntPtr<vfs::FileSystem> FS) 50 : FS(FS), FileSystemOpts(FSO), 51 SeenDirEntries(64), SeenFileEntries(64), NextFileUID(0) { 52 NumDirLookups = NumFileLookups = 0; 53 NumDirCacheMisses = NumFileCacheMisses = 0; 54 55 // If the caller doesn't provide a virtual file system, just grab the real 56 // file system. 57 if (!FS) 58 this->FS = vfs::getRealFileSystem(); 59 } 60 61 FileManager::~FileManager() = default; 62 63 void FileManager::addStatCache(std::unique_ptr<FileSystemStatCache> statCache, 64 bool AtBeginning) { 65 assert(statCache && "No stat cache provided?"); 66 if (AtBeginning || !StatCache.get()) { 67 statCache->setNextStatCache(std::move(StatCache)); 68 StatCache = std::move(statCache); 69 return; 70 } 71 72 FileSystemStatCache *LastCache = StatCache.get(); 73 while (LastCache->getNextStatCache()) 74 LastCache = LastCache->getNextStatCache(); 75 76 LastCache->setNextStatCache(std::move(statCache)); 77 } 78 79 void FileManager::removeStatCache(FileSystemStatCache *statCache) { 80 if (!statCache) 81 return; 82 83 if (StatCache.get() == statCache) { 84 // This is the first stat cache. 85 StatCache = StatCache->takeNextStatCache(); 86 return; 87 } 88 89 // Find the stat cache in the list. 90 FileSystemStatCache *PrevCache = StatCache.get(); 91 while (PrevCache && PrevCache->getNextStatCache() != statCache) 92 PrevCache = PrevCache->getNextStatCache(); 93 94 assert(PrevCache && "Stat cache not found for removal"); 95 PrevCache->setNextStatCache(statCache->takeNextStatCache()); 96 } 97 98 void FileManager::clearStatCaches() { 99 StatCache.reset(); 100 } 101 102 /// \brief Retrieve the directory that the given file name resides in. 103 /// Filename can point to either a real file or a virtual file. 104 static const DirectoryEntry *getDirectoryFromFile(FileManager &FileMgr, 105 StringRef Filename, 106 bool CacheFailure) { 107 if (Filename.empty()) 108 return nullptr; 109 110 if (llvm::sys::path::is_separator(Filename[Filename.size() - 1])) 111 return nullptr; // If Filename is a directory. 112 113 StringRef DirName = llvm::sys::path::parent_path(Filename); 114 // Use the current directory if file has no path component. 115 if (DirName.empty()) 116 DirName = "."; 117 118 return FileMgr.getDirectory(DirName, CacheFailure); 119 } 120 121 /// Add all ancestors of the given path (pointing to either a file or 122 /// a directory) as virtual directories. 123 void FileManager::addAncestorsAsVirtualDirs(StringRef Path) { 124 StringRef DirName = llvm::sys::path::parent_path(Path); 125 if (DirName.empty()) 126 DirName = "."; 127 128 auto &NamedDirEnt = 129 *SeenDirEntries.insert(std::make_pair(DirName, nullptr)).first; 130 131 // When caching a virtual directory, we always cache its ancestors 132 // at the same time. Therefore, if DirName is already in the cache, 133 // we don't need to recurse as its ancestors must also already be in 134 // the cache. 135 if (NamedDirEnt.second && NamedDirEnt.second != NON_EXISTENT_DIR) 136 return; 137 138 // Add the virtual directory to the cache. 139 auto UDE = llvm::make_unique<DirectoryEntry>(); 140 UDE->Name = NamedDirEnt.first().data(); 141 NamedDirEnt.second = UDE.get(); 142 VirtualDirectoryEntries.push_back(std::move(UDE)); 143 144 // Recursively add the other ancestors. 145 addAncestorsAsVirtualDirs(DirName); 146 } 147 148 const DirectoryEntry *FileManager::getDirectory(StringRef DirName, 149 bool CacheFailure) { 150 // stat doesn't like trailing separators except for root directory. 151 // At least, on Win32 MSVCRT, stat() cannot strip trailing '/'. 152 // (though it can strip '\\') 153 if (DirName.size() > 1 && 154 DirName != llvm::sys::path::root_path(DirName) && 155 llvm::sys::path::is_separator(DirName.back())) 156 DirName = DirName.substr(0, DirName.size()-1); 157 #ifdef LLVM_ON_WIN32 158 // Fixing a problem with "clang C:test.c" on Windows. 159 // Stat("C:") does not recognize "C:" as a valid directory 160 std::string DirNameStr; 161 if (DirName.size() > 1 && DirName.back() == ':' && 162 DirName.equals_lower(llvm::sys::path::root_name(DirName))) { 163 DirNameStr = DirName.str() + '.'; 164 DirName = DirNameStr; 165 } 166 #endif 167 168 ++NumDirLookups; 169 auto &NamedDirEnt = 170 *SeenDirEntries.insert(std::make_pair(DirName, nullptr)).first; 171 172 // See if there was already an entry in the map. Note that the map 173 // contains both virtual and real directories. 174 if (NamedDirEnt.second) 175 return NamedDirEnt.second == NON_EXISTENT_DIR ? nullptr 176 : NamedDirEnt.second; 177 178 ++NumDirCacheMisses; 179 180 // By default, initialize it to invalid. 181 NamedDirEnt.second = NON_EXISTENT_DIR; 182 183 // Get the null-terminated directory name as stored as the key of the 184 // SeenDirEntries map. 185 const char *InterndDirName = NamedDirEnt.first().data(); 186 187 // Check to see if the directory exists. 188 FileData Data; 189 if (getStatValue(InterndDirName, Data, false, nullptr /*directory lookup*/)) { 190 // There's no real directory at the given path. 191 if (!CacheFailure) 192 SeenDirEntries.erase(DirName); 193 return nullptr; 194 } 195 196 // It exists. See if we have already opened a directory with the 197 // same inode (this occurs on Unix-like systems when one dir is 198 // symlinked to another, for example) or the same path (on 199 // Windows). 200 DirectoryEntry &UDE = UniqueRealDirs[Data.UniqueID]; 201 202 NamedDirEnt.second = &UDE; 203 if (!UDE.getName()) { 204 // We don't have this directory yet, add it. We use the string 205 // key from the SeenDirEntries map as the string. 206 UDE.Name = InterndDirName; 207 } 208 209 return &UDE; 210 } 211 212 const FileEntry *FileManager::getFile(StringRef Filename, bool openFile, 213 bool CacheFailure) { 214 ++NumFileLookups; 215 216 // See if there is already an entry in the map. 217 auto &NamedFileEnt = 218 *SeenFileEntries.insert(std::make_pair(Filename, nullptr)).first; 219 220 // See if there is already an entry in the map. 221 if (NamedFileEnt.second) 222 return NamedFileEnt.second == NON_EXISTENT_FILE ? nullptr 223 : NamedFileEnt.second; 224 225 ++NumFileCacheMisses; 226 227 // By default, initialize it to invalid. 228 NamedFileEnt.second = NON_EXISTENT_FILE; 229 230 // Get the null-terminated file name as stored as the key of the 231 // SeenFileEntries map. 232 const char *InterndFileName = NamedFileEnt.first().data(); 233 234 // Look up the directory for the file. When looking up something like 235 // sys/foo.h we'll discover all of the search directories that have a 'sys' 236 // subdirectory. This will let us avoid having to waste time on known-to-fail 237 // searches when we go to find sys/bar.h, because all the search directories 238 // without a 'sys' subdir will get a cached failure result. 239 const DirectoryEntry *DirInfo = getDirectoryFromFile(*this, Filename, 240 CacheFailure); 241 if (DirInfo == nullptr) { // Directory doesn't exist, file can't exist. 242 if (!CacheFailure) 243 SeenFileEntries.erase(Filename); 244 245 return nullptr; 246 } 247 248 // FIXME: Use the directory info to prune this, before doing the stat syscall. 249 // FIXME: This will reduce the # syscalls. 250 251 // Nope, there isn't. Check to see if the file exists. 252 std::unique_ptr<vfs::File> F; 253 FileData Data; 254 if (getStatValue(InterndFileName, Data, true, openFile ? &F : nullptr)) { 255 // There's no real file at the given path. 256 if (!CacheFailure) 257 SeenFileEntries.erase(Filename); 258 259 return nullptr; 260 } 261 262 assert((openFile || !F) && "undesired open file"); 263 264 // It exists. See if we have already opened a file with the same inode. 265 // This occurs when one dir is symlinked to another, for example. 266 FileEntry &UFE = UniqueRealFiles[Data.UniqueID]; 267 268 NamedFileEnt.second = &UFE; 269 270 // If the name returned by getStatValue is different than Filename, re-intern 271 // the name. 272 if (Data.Name != Filename) { 273 auto &NamedFileEnt = 274 *SeenFileEntries.insert(std::make_pair(Data.Name, nullptr)).first; 275 if (!NamedFileEnt.second) 276 NamedFileEnt.second = &UFE; 277 else 278 assert(NamedFileEnt.second == &UFE && 279 "filename from getStatValue() refers to wrong file"); 280 InterndFileName = NamedFileEnt.first().data(); 281 } 282 283 if (UFE.isValid()) { // Already have an entry with this inode, return it. 284 285 // FIXME: this hack ensures that if we look up a file by a virtual path in 286 // the VFS that the getDir() will have the virtual path, even if we found 287 // the file by a 'real' path first. This is required in order to find a 288 // module's structure when its headers/module map are mapped in the VFS. 289 // We should remove this as soon as we can properly support a file having 290 // multiple names. 291 if (DirInfo != UFE.Dir && Data.IsVFSMapped) 292 UFE.Dir = DirInfo; 293 294 // Always update the name to use the last name by which a file was accessed. 295 // FIXME: Neither this nor always using the first name is correct; we want 296 // to switch towards a design where we return a FileName object that 297 // encapsulates both the name by which the file was accessed and the 298 // corresponding FileEntry. 299 UFE.Name = InterndFileName; 300 301 return &UFE; 302 } 303 304 // Otherwise, we don't have this file yet, add it. 305 UFE.Name = InterndFileName; 306 UFE.Size = Data.Size; 307 UFE.ModTime = Data.ModTime; 308 UFE.Dir = DirInfo; 309 UFE.UID = NextFileUID++; 310 UFE.UniqueID = Data.UniqueID; 311 UFE.IsNamedPipe = Data.IsNamedPipe; 312 UFE.InPCH = Data.InPCH; 313 UFE.File = std::move(F); 314 UFE.IsValid = true; 315 if (UFE.File) 316 if (auto RealPathName = UFE.File->getName()) 317 UFE.RealPathName = *RealPathName; 318 return &UFE; 319 } 320 321 const FileEntry * 322 FileManager::getVirtualFile(StringRef Filename, off_t Size, 323 time_t ModificationTime) { 324 ++NumFileLookups; 325 326 // See if there is already an entry in the map. 327 auto &NamedFileEnt = 328 *SeenFileEntries.insert(std::make_pair(Filename, nullptr)).first; 329 330 // See if there is already an entry in the map. 331 if (NamedFileEnt.second && NamedFileEnt.second != NON_EXISTENT_FILE) 332 return NamedFileEnt.second; 333 334 ++NumFileCacheMisses; 335 336 // By default, initialize it to invalid. 337 NamedFileEnt.second = NON_EXISTENT_FILE; 338 339 addAncestorsAsVirtualDirs(Filename); 340 FileEntry *UFE = nullptr; 341 342 // Now that all ancestors of Filename are in the cache, the 343 // following call is guaranteed to find the DirectoryEntry from the 344 // cache. 345 const DirectoryEntry *DirInfo = getDirectoryFromFile(*this, Filename, 346 /*CacheFailure=*/true); 347 assert(DirInfo && 348 "The directory of a virtual file should already be in the cache."); 349 350 // Check to see if the file exists. If so, drop the virtual file 351 FileData Data; 352 const char *InterndFileName = NamedFileEnt.first().data(); 353 if (getStatValue(InterndFileName, Data, true, nullptr) == 0) { 354 Data.Size = Size; 355 Data.ModTime = ModificationTime; 356 UFE = &UniqueRealFiles[Data.UniqueID]; 357 358 NamedFileEnt.second = UFE; 359 360 // If we had already opened this file, close it now so we don't 361 // leak the descriptor. We're not going to use the file 362 // descriptor anyway, since this is a virtual file. 363 if (UFE->File) 364 UFE->closeFile(); 365 366 // If we already have an entry with this inode, return it. 367 if (UFE->isValid()) 368 return UFE; 369 370 UFE->UniqueID = Data.UniqueID; 371 UFE->IsNamedPipe = Data.IsNamedPipe; 372 UFE->InPCH = Data.InPCH; 373 } 374 375 if (!UFE) { 376 VirtualFileEntries.push_back(llvm::make_unique<FileEntry>()); 377 UFE = VirtualFileEntries.back().get(); 378 NamedFileEnt.second = UFE; 379 } 380 381 UFE->Name = InterndFileName; 382 UFE->Size = Size; 383 UFE->ModTime = ModificationTime; 384 UFE->Dir = DirInfo; 385 UFE->UID = NextFileUID++; 386 UFE->File.reset(); 387 return UFE; 388 } 389 390 bool FileManager::FixupRelativePath(SmallVectorImpl<char> &path) const { 391 StringRef pathRef(path.data(), path.size()); 392 393 if (FileSystemOpts.WorkingDir.empty() 394 || llvm::sys::path::is_absolute(pathRef)) 395 return false; 396 397 SmallString<128> NewPath(FileSystemOpts.WorkingDir); 398 llvm::sys::path::append(NewPath, pathRef); 399 path = NewPath; 400 return true; 401 } 402 403 bool FileManager::makeAbsolutePath(SmallVectorImpl<char> &Path) const { 404 bool Changed = FixupRelativePath(Path); 405 406 if (!llvm::sys::path::is_absolute(StringRef(Path.data(), Path.size()))) { 407 llvm::sys::fs::make_absolute(Path); 408 Changed = true; 409 } 410 411 return Changed; 412 } 413 414 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> 415 FileManager::getBufferForFile(const FileEntry *Entry, bool isVolatile, 416 bool ShouldCloseOpenFile) { 417 uint64_t FileSize = Entry->getSize(); 418 // If there's a high enough chance that the file have changed since we 419 // got its size, force a stat before opening it. 420 if (isVolatile) 421 FileSize = -1; 422 423 const char *Filename = Entry->getName(); 424 // If the file is already open, use the open file descriptor. 425 if (Entry->File) { 426 auto Result = 427 Entry->File->getBuffer(Filename, FileSize, 428 /*RequiresNullTerminator=*/true, isVolatile); 429 // FIXME: we need a set of APIs that can make guarantees about whether a 430 // FileEntry is open or not. 431 if (ShouldCloseOpenFile) 432 Entry->closeFile(); 433 return Result; 434 } 435 436 // Otherwise, open the file. 437 438 if (FileSystemOpts.WorkingDir.empty()) 439 return FS->getBufferForFile(Filename, FileSize, 440 /*RequiresNullTerminator=*/true, isVolatile); 441 442 SmallString<128> FilePath(Entry->getName()); 443 FixupRelativePath(FilePath); 444 return FS->getBufferForFile(FilePath, FileSize, 445 /*RequiresNullTerminator=*/true, isVolatile); 446 } 447 448 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> 449 FileManager::getBufferForFile(StringRef Filename) { 450 if (FileSystemOpts.WorkingDir.empty()) 451 return FS->getBufferForFile(Filename); 452 453 SmallString<128> FilePath(Filename); 454 FixupRelativePath(FilePath); 455 return FS->getBufferForFile(FilePath.c_str()); 456 } 457 458 /// getStatValue - Get the 'stat' information for the specified path, 459 /// using the cache to accelerate it if possible. This returns true 460 /// if the path points to a virtual file or does not exist, or returns 461 /// false if it's an existent real file. If FileDescriptor is NULL, 462 /// do directory look-up instead of file look-up. 463 bool FileManager::getStatValue(const char *Path, FileData &Data, bool isFile, 464 std::unique_ptr<vfs::File> *F) { 465 // FIXME: FileSystemOpts shouldn't be passed in here, all paths should be 466 // absolute! 467 if (FileSystemOpts.WorkingDir.empty()) 468 return FileSystemStatCache::get(Path, Data, isFile, F,StatCache.get(), *FS); 469 470 SmallString<128> FilePath(Path); 471 FixupRelativePath(FilePath); 472 473 return FileSystemStatCache::get(FilePath.c_str(), Data, isFile, F, 474 StatCache.get(), *FS); 475 } 476 477 bool FileManager::getNoncachedStatValue(StringRef Path, 478 vfs::Status &Result) { 479 SmallString<128> FilePath(Path); 480 FixupRelativePath(FilePath); 481 482 llvm::ErrorOr<vfs::Status> S = FS->status(FilePath.c_str()); 483 if (!S) 484 return true; 485 Result = *S; 486 return false; 487 } 488 489 void FileManager::invalidateCache(const FileEntry *Entry) { 490 assert(Entry && "Cannot invalidate a NULL FileEntry"); 491 492 SeenFileEntries.erase(Entry->getName()); 493 494 // FileEntry invalidation should not block future optimizations in the file 495 // caches. Possible alternatives are cache truncation (invalidate last N) or 496 // invalidation of the whole cache. 497 UniqueRealFiles.erase(Entry->getUniqueID()); 498 } 499 500 501 void FileManager::GetUniqueIDMapping( 502 SmallVectorImpl<const FileEntry *> &UIDToFiles) const { 503 UIDToFiles.clear(); 504 UIDToFiles.resize(NextFileUID); 505 506 // Map file entries 507 for (llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator>::const_iterator 508 FE = SeenFileEntries.begin(), FEEnd = SeenFileEntries.end(); 509 FE != FEEnd; ++FE) 510 if (FE->getValue() && FE->getValue() != NON_EXISTENT_FILE) 511 UIDToFiles[FE->getValue()->getUID()] = FE->getValue(); 512 513 // Map virtual file entries 514 for (const auto &VFE : VirtualFileEntries) 515 if (VFE && VFE.get() != NON_EXISTENT_FILE) 516 UIDToFiles[VFE->getUID()] = VFE.get(); 517 } 518 519 void FileManager::modifyFileEntry(FileEntry *File, 520 off_t Size, time_t ModificationTime) { 521 File->Size = Size; 522 File->ModTime = ModificationTime; 523 } 524 525 StringRef FileManager::getCanonicalName(const DirectoryEntry *Dir) { 526 // FIXME: use llvm::sys::fs::canonical() when it gets implemented 527 llvm::DenseMap<const DirectoryEntry *, llvm::StringRef>::iterator Known 528 = CanonicalDirNames.find(Dir); 529 if (Known != CanonicalDirNames.end()) 530 return Known->second; 531 532 StringRef CanonicalName(Dir->getName()); 533 534 #ifdef LLVM_ON_UNIX 535 char CanonicalNameBuf[PATH_MAX]; 536 if (realpath(Dir->getName(), CanonicalNameBuf)) 537 CanonicalName = StringRef(CanonicalNameBuf).copy(CanonicalNameStorage); 538 #else 539 SmallString<256> CanonicalNameBuf(CanonicalName); 540 llvm::sys::fs::make_absolute(CanonicalNameBuf); 541 llvm::sys::path::native(CanonicalNameBuf); 542 // We've run into needing to remove '..' here in the wild though, so 543 // remove it. 544 // On Windows, symlinks are significantly less prevalent, so removing 545 // '..' is pretty safe. 546 // Ideally we'd have an equivalent of `realpath` and could implement 547 // sys::fs::canonical across all the platforms. 548 llvm::sys::path::remove_dots(CanonicalNameBuf, /* remove_dot_dot */ true); 549 CanonicalName = StringRef(CanonicalNameBuf).copy(CanonicalNameStorage); 550 #endif 551 552 CanonicalDirNames.insert(std::make_pair(Dir, CanonicalName)); 553 return CanonicalName; 554 } 555 556 void FileManager::PrintStats() const { 557 llvm::errs() << "\n*** File Manager Stats:\n"; 558 llvm::errs() << UniqueRealFiles.size() << " real files found, " 559 << UniqueRealDirs.size() << " real dirs found.\n"; 560 llvm::errs() << VirtualFileEntries.size() << " virtual files found, " 561 << VirtualDirectoryEntries.size() << " virtual dirs found.\n"; 562 llvm::errs() << NumDirLookups << " dir lookups, " 563 << NumDirCacheMisses << " dir cache misses.\n"; 564 llvm::errs() << NumFileLookups << " file lookups, " 565 << NumFileCacheMisses << " file cache misses.\n"; 566 567 //llvm::errs() << PagesMapped << BytesOfPagesMapped << FSLookups; 568 } 569