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PrecompiledPreamble.cpp
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1 //===--- PrecompiledPreamble.cpp - Build precompiled preambles --*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Helper class to build precompiled preamble.
10 //
11 //===----------------------------------------------------------------------===//
12 
14 #include "clang/AST/DeclObjC.h"
15 #include "clang/Basic/TargetInfo.h"
20 #include "clang/Lex/Lexer.h"
21 #include "clang/Lex/Preprocessor.h"
24 #include "llvm/ADT/StringExtras.h"
25 #include "llvm/ADT/StringSet.h"
26 #include "llvm/Config/llvm-config.h"
27 #include "llvm/Support/CrashRecoveryContext.h"
28 #include "llvm/Support/FileSystem.h"
29 #include "llvm/Support/Mutex.h"
30 #include "llvm/Support/MutexGuard.h"
31 #include "llvm/Support/Process.h"
32 #include "llvm/Support/VirtualFileSystem.h"
33 #include <limits>
34 #include <utility>
35 
36 using namespace clang;
37 
38 namespace {
39 
40 StringRef getInMemoryPreamblePath() {
41 #if defined(LLVM_ON_UNIX)
42  return "/__clang_tmp/___clang_inmemory_preamble___";
43 #elif defined(_WIN32)
44  return "C:\\__clang_tmp\\___clang_inmemory_preamble___";
45 #else
46 #warning "Unknown platform. Defaulting to UNIX-style paths for in-memory PCHs"
47  return "/__clang_tmp/___clang_inmemory_preamble___";
48 #endif
49 }
50 
52 createVFSOverlayForPreamblePCH(StringRef PCHFilename,
53  std::unique_ptr<llvm::MemoryBuffer> PCHBuffer,
55  // We want only the PCH file from the real filesystem to be available,
56  // so we create an in-memory VFS with just that and overlay it on top.
58  new llvm::vfs::InMemoryFileSystem());
59  PCHFS->addFile(PCHFilename, 0, std::move(PCHBuffer));
61  new llvm::vfs::OverlayFileSystem(VFS));
62  Overlay->pushOverlay(PCHFS);
63  return Overlay;
64 }
65 
66 class PreambleDependencyCollector : public DependencyCollector {
67 public:
68  // We want to collect all dependencies for correctness. Avoiding the real
69  // system dependencies (e.g. stl from /usr/lib) would probably be a good idea,
70  // but there is no way to distinguish between those and the ones that can be
71  // spuriously added by '-isystem' (e.g. to suppress warnings from those
72  // headers).
73  bool needSystemDependencies() override { return true; }
74 };
75 
76 /// Keeps a track of files to be deleted in destructor.
77 class TemporaryFiles {
78 public:
79  // A static instance to be used by all clients.
80  static TemporaryFiles &getInstance();
81 
82 private:
83  // Disallow constructing the class directly.
84  TemporaryFiles() = default;
85  // Disallow copy.
86  TemporaryFiles(const TemporaryFiles &) = delete;
87 
88 public:
89  ~TemporaryFiles();
90 
91  /// Adds \p File to a set of tracked files.
92  void addFile(StringRef File);
93 
94  /// Remove \p File from disk and from the set of tracked files.
95  void removeFile(StringRef File);
96 
97 private:
98  llvm::sys::SmartMutex<false> Mutex;
99  llvm::StringSet<> Files;
100 };
101 
102 TemporaryFiles &TemporaryFiles::getInstance() {
103  static TemporaryFiles Instance;
104  return Instance;
105 }
106 
107 TemporaryFiles::~TemporaryFiles() {
108  llvm::MutexGuard Guard(Mutex);
109  for (const auto &File : Files)
110  llvm::sys::fs::remove(File.getKey());
111 }
112 
113 void TemporaryFiles::addFile(StringRef File) {
114  llvm::MutexGuard Guard(Mutex);
115  auto IsInserted = Files.insert(File).second;
116  (void)IsInserted;
117  assert(IsInserted && "File has already been added");
118 }
119 
120 void TemporaryFiles::removeFile(StringRef File) {
121  llvm::MutexGuard Guard(Mutex);
122  auto WasPresent = Files.erase(File);
123  (void)WasPresent;
124  assert(WasPresent && "File was not tracked");
125  llvm::sys::fs::remove(File);
126 }
127 
128 class PrecompilePreambleAction : public ASTFrontendAction {
129 public:
130  PrecompilePreambleAction(std::string *InMemStorage,
131  PreambleCallbacks &Callbacks)
132  : InMemStorage(InMemStorage), Callbacks(Callbacks) {}
133 
134  std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
135  StringRef InFile) override;
136 
137  bool hasEmittedPreamblePCH() const { return HasEmittedPreamblePCH; }
138 
139  void setEmittedPreamblePCH(ASTWriter &Writer) {
140  this->HasEmittedPreamblePCH = true;
141  Callbacks.AfterPCHEmitted(Writer);
142  }
143 
144  bool shouldEraseOutputFiles() override { return !hasEmittedPreamblePCH(); }
145  bool hasCodeCompletionSupport() const override { return false; }
146  bool hasASTFileSupport() const override { return false; }
147  TranslationUnitKind getTranslationUnitKind() override { return TU_Prefix; }
148 
149 private:
150  friend class PrecompilePreambleConsumer;
151 
152  bool HasEmittedPreamblePCH = false;
153  std::string *InMemStorage;
154  PreambleCallbacks &Callbacks;
155 };
156 
157 class PrecompilePreambleConsumer : public PCHGenerator {
158 public:
159  PrecompilePreambleConsumer(PrecompilePreambleAction &Action,
160  const Preprocessor &PP,
161  InMemoryModuleCache &ModuleCache,
162  StringRef isysroot,
163  std::unique_ptr<raw_ostream> Out)
164  : PCHGenerator(PP, ModuleCache, "", isysroot,
165  std::make_shared<PCHBuffer>(),
166  ArrayRef<std::shared_ptr<ModuleFileExtension>>(),
167  /*AllowASTWithErrors=*/true),
168  Action(Action), Out(std::move(Out)) {}
169 
170  bool HandleTopLevelDecl(DeclGroupRef DG) override {
171  Action.Callbacks.HandleTopLevelDecl(DG);
172  return true;
173  }
174 
175  void HandleTranslationUnit(ASTContext &Ctx) override {
177  if (!hasEmittedPCH())
178  return;
179 
180  // Write the generated bitstream to "Out".
181  *Out << getPCH();
182  // Make sure it hits disk now.
183  Out->flush();
184  // Free the buffer.
186  getPCH() = std::move(Empty);
187 
188  Action.setEmittedPreamblePCH(getWriter());
189  }
190 
191 private:
192  PrecompilePreambleAction &Action;
193  std::unique_ptr<raw_ostream> Out;
194 };
195 
196 std::unique_ptr<ASTConsumer>
197 PrecompilePreambleAction::CreateASTConsumer(CompilerInstance &CI,
198  StringRef InFile) {
199  std::string Sysroot;
201  return nullptr;
202 
203  std::unique_ptr<llvm::raw_ostream> OS;
204  if (InMemStorage) {
205  OS = llvm::make_unique<llvm::raw_string_ostream>(*InMemStorage);
206  } else {
207  std::string OutputFile;
208  OS = GeneratePCHAction::CreateOutputFile(CI, InFile, OutputFile);
209  }
210  if (!OS)
211  return nullptr;
212 
214  Sysroot.clear();
215 
216  return llvm::make_unique<PrecompilePreambleConsumer>(
217  *this, CI.getPreprocessor(), CI.getModuleCache(), Sysroot, std::move(OS));
218 }
219 
220 template <class T> bool moveOnNoError(llvm::ErrorOr<T> Val, T &Output) {
221  if (!Val)
222  return false;
223  Output = std::move(*Val);
224  return true;
225 }
226 
227 } // namespace
228 
230  llvm::MemoryBuffer *Buffer,
231  unsigned MaxLines) {
232  return Lexer::ComputePreamble(Buffer->getBuffer(), LangOpts, MaxLines);
233 }
234 
235 llvm::ErrorOr<PrecompiledPreamble> PrecompiledPreamble::Build(
236  const CompilerInvocation &Invocation,
237  const llvm::MemoryBuffer *MainFileBuffer, PreambleBounds Bounds,
238  DiagnosticsEngine &Diagnostics,
240  std::shared_ptr<PCHContainerOperations> PCHContainerOps, bool StoreInMemory,
241  PreambleCallbacks &Callbacks) {
242  assert(VFS && "VFS is null");
243 
244  auto PreambleInvocation = std::make_shared<CompilerInvocation>(Invocation);
245  FrontendOptions &FrontendOpts = PreambleInvocation->getFrontendOpts();
246  PreprocessorOptions &PreprocessorOpts =
247  PreambleInvocation->getPreprocessorOpts();
248 
250  if (!StoreInMemory) {
251  // Create a temporary file for the precompiled preamble. In rare
252  // circumstances, this can fail.
253  llvm::ErrorOr<PrecompiledPreamble::TempPCHFile> PreamblePCHFile =
254  PrecompiledPreamble::TempPCHFile::CreateNewPreamblePCHFile();
255  if (!PreamblePCHFile)
257  TempFile = std::move(*PreamblePCHFile);
258  }
259 
260  PCHStorage Storage = StoreInMemory ? PCHStorage(InMemoryPreamble())
261  : PCHStorage(std::move(*TempFile));
262 
263  // Save the preamble text for later; we'll need to compare against it for
264  // subsequent reparses.
265  std::vector<char> PreambleBytes(MainFileBuffer->getBufferStart(),
266  MainFileBuffer->getBufferStart() +
267  Bounds.Size);
268  bool PreambleEndsAtStartOfLine = Bounds.PreambleEndsAtStartOfLine;
269 
270  // Tell the compiler invocation to generate a temporary precompiled header.
271  FrontendOpts.ProgramAction = frontend::GeneratePCH;
272  FrontendOpts.OutputFile = StoreInMemory ? getInMemoryPreamblePath()
273  : Storage.asFile().getFilePath();
274  PreprocessorOpts.PrecompiledPreambleBytes.first = 0;
275  PreprocessorOpts.PrecompiledPreambleBytes.second = false;
276  // Inform preprocessor to record conditional stack when building the preamble.
277  PreprocessorOpts.GeneratePreamble = true;
278 
279  // Create the compiler instance to use for building the precompiled preamble.
280  std::unique_ptr<CompilerInstance> Clang(
281  new CompilerInstance(std::move(PCHContainerOps)));
282 
283  // Recover resources if we crash before exiting this method.
284  llvm::CrashRecoveryContextCleanupRegistrar<CompilerInstance> CICleanup(
285  Clang.get());
286 
287  Clang->setInvocation(std::move(PreambleInvocation));
288  Clang->setDiagnostics(&Diagnostics);
289 
290  // Create the target instance.
291  Clang->setTarget(TargetInfo::CreateTargetInfo(
292  Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
293  if (!Clang->hasTarget())
295 
296  // Inform the target of the language options.
297  //
298  // FIXME: We shouldn't need to do this, the target should be immutable once
299  // created. This complexity should be lifted elsewhere.
300  Clang->getTarget().adjust(Clang->getLangOpts());
301 
302  assert(Clang->getFrontendOpts().Inputs.size() == 1 &&
303  "Invocation must have exactly one source file!");
304  assert(Clang->getFrontendOpts().Inputs[0].getKind().getFormat() ==
306  "FIXME: AST inputs not yet supported here!");
307  assert(Clang->getFrontendOpts().Inputs[0].getKind().getLanguage() !=
309  "IR inputs not support here!");
310 
311  // Clear out old caches and data.
312  Diagnostics.Reset();
313  ProcessWarningOptions(Diagnostics, Clang->getDiagnosticOpts());
314 
315  VFS =
316  createVFSFromCompilerInvocation(Clang->getInvocation(), Diagnostics, VFS);
317 
318  // Create a file manager object to provide access to and cache the filesystem.
319  Clang->setFileManager(new FileManager(Clang->getFileSystemOpts(), VFS));
320 
321  // Create the source manager.
322  Clang->setSourceManager(
323  new SourceManager(Diagnostics, Clang->getFileManager()));
324 
325  auto PreambleDepCollector = std::make_shared<PreambleDependencyCollector>();
326  Clang->addDependencyCollector(PreambleDepCollector);
327 
328  // Remap the main source file to the preamble buffer.
329  StringRef MainFilePath = FrontendOpts.Inputs[0].getFile();
330  auto PreambleInputBuffer = llvm::MemoryBuffer::getMemBufferCopy(
331  MainFileBuffer->getBuffer().slice(0, Bounds.Size), MainFilePath);
332  if (PreprocessorOpts.RetainRemappedFileBuffers) {
333  // MainFileBuffer will be deleted by unique_ptr after leaving the method.
334  PreprocessorOpts.addRemappedFile(MainFilePath, PreambleInputBuffer.get());
335  } else {
336  // In that case, remapped buffer will be deleted by CompilerInstance on
337  // BeginSourceFile, so we call release() to avoid double deletion.
338  PreprocessorOpts.addRemappedFile(MainFilePath,
339  PreambleInputBuffer.release());
340  }
341 
342  std::unique_ptr<PrecompilePreambleAction> Act;
343  Act.reset(new PrecompilePreambleAction(
344  StoreInMemory ? &Storage.asMemory().Data : nullptr, Callbacks));
345  Callbacks.BeforeExecute(*Clang);
346  if (!Act->BeginSourceFile(*Clang.get(), Clang->getFrontendOpts().Inputs[0]))
348 
349  std::unique_ptr<PPCallbacks> DelegatedPPCallbacks =
350  Callbacks.createPPCallbacks();
351  if (DelegatedPPCallbacks)
352  Clang->getPreprocessor().addPPCallbacks(std::move(DelegatedPPCallbacks));
353  if (auto CommentHandler = Callbacks.getCommentHandler())
354  Clang->getPreprocessor().addCommentHandler(CommentHandler);
355 
356  Act->Execute();
357 
358  // Run the callbacks.
359  Callbacks.AfterExecute(*Clang);
360 
361  Act->EndSourceFile();
362 
363  if (!Act->hasEmittedPreamblePCH())
365 
366  // Keep track of all of the files that the source manager knows about,
367  // so we can verify whether they have changed or not.
368  llvm::StringMap<PrecompiledPreamble::PreambleFileHash> FilesInPreamble;
369 
370  SourceManager &SourceMgr = Clang->getSourceManager();
371  for (auto &Filename : PreambleDepCollector->getDependencies()) {
372  const FileEntry *File = Clang->getFileManager().getFile(Filename);
373  if (!File || File == SourceMgr.getFileEntryForID(SourceMgr.getMainFileID()))
374  continue;
375  if (time_t ModTime = File->getModificationTime()) {
376  FilesInPreamble[File->getName()] =
377  PrecompiledPreamble::PreambleFileHash::createForFile(File->getSize(),
378  ModTime);
379  } else {
380  llvm::MemoryBuffer *Buffer = SourceMgr.getMemoryBufferForFile(File);
381  FilesInPreamble[File->getName()] =
382  PrecompiledPreamble::PreambleFileHash::createForMemoryBuffer(Buffer);
383  }
384  }
385 
386  return PrecompiledPreamble(std::move(Storage), std::move(PreambleBytes),
387  PreambleEndsAtStartOfLine,
388  std::move(FilesInPreamble));
389 }
390 
392  return PreambleBounds(PreambleBytes.size(), PreambleEndsAtStartOfLine);
393 }
394 
396  switch (Storage.getKind()) {
397  case PCHStorage::Kind::Empty:
398  assert(false && "Calling getSize() on invalid PrecompiledPreamble. "
399  "Was it std::moved?");
400  return 0;
401  case PCHStorage::Kind::InMemory:
402  return Storage.asMemory().Data.size();
403  case PCHStorage::Kind::TempFile: {
404  uint64_t Result;
405  if (llvm::sys::fs::file_size(Storage.asFile().getFilePath(), Result))
406  return 0;
407 
408  assert(Result <= std::numeric_limits<std::size_t>::max() &&
409  "file size did not fit into size_t");
410  return Result;
411  }
412  }
413  llvm_unreachable("Unhandled storage kind");
414 }
415 
417  const llvm::MemoryBuffer *MainFileBuffer,
418  PreambleBounds Bounds,
419  llvm::vfs::FileSystem *VFS) const {
420 
421  assert(
422  Bounds.Size <= MainFileBuffer->getBufferSize() &&
423  "Buffer is too large. Bounds were calculated from a different buffer?");
424 
425  auto PreambleInvocation = std::make_shared<CompilerInvocation>(Invocation);
426  PreprocessorOptions &PreprocessorOpts =
427  PreambleInvocation->getPreprocessorOpts();
428 
429  // We've previously computed a preamble. Check whether we have the same
430  // preamble now that we did before, and that there's enough space in
431  // the main-file buffer within the precompiled preamble to fit the
432  // new main file.
433  if (PreambleBytes.size() != Bounds.Size ||
434  PreambleEndsAtStartOfLine != Bounds.PreambleEndsAtStartOfLine ||
435  !std::equal(PreambleBytes.begin(), PreambleBytes.end(),
436  MainFileBuffer->getBuffer().begin()))
437  return false;
438  // The preamble has not changed. We may be able to re-use the precompiled
439  // preamble.
440 
441  // Check that none of the files used by the preamble have changed.
442  // First, make a record of those files that have been overridden via
443  // remapping or unsaved_files.
444  std::map<llvm::sys::fs::UniqueID, PreambleFileHash> OverriddenFiles;
445  for (const auto &R : PreprocessorOpts.RemappedFiles) {
446  llvm::vfs::Status Status;
447  if (!moveOnNoError(VFS->status(R.second), Status)) {
448  // If we can't stat the file we're remapping to, assume that something
449  // horrible happened.
450  return false;
451  }
452 
453  OverriddenFiles[Status.getUniqueID()] = PreambleFileHash::createForFile(
454  Status.getSize(), llvm::sys::toTimeT(Status.getLastModificationTime()));
455  }
456 
457  for (const auto &RB : PreprocessorOpts.RemappedFileBuffers) {
458  llvm::vfs::Status Status;
459  if (!moveOnNoError(VFS->status(RB.first), Status))
460  return false;
461 
462  OverriddenFiles[Status.getUniqueID()] =
463  PreambleFileHash::createForMemoryBuffer(RB.second);
464  }
465 
466  // Check whether anything has changed.
467  for (const auto &F : FilesInPreamble) {
468  llvm::vfs::Status Status;
469  if (!moveOnNoError(VFS->status(F.first()), Status)) {
470  // If we can't stat the file, assume that something horrible happened.
471  return false;
472  }
473 
474  std::map<llvm::sys::fs::UniqueID, PreambleFileHash>::iterator Overridden =
475  OverriddenFiles.find(Status.getUniqueID());
476  if (Overridden != OverriddenFiles.end()) {
477  // This file was remapped; check whether the newly-mapped file
478  // matches up with the previous mapping.
479  if (Overridden->second != F.second)
480  return false;
481  continue;
482  }
483 
484  // The file was not remapped; check whether it has changed on disk.
485  if (Status.getSize() != uint64_t(F.second.Size) ||
486  llvm::sys::toTimeT(Status.getLastModificationTime()) !=
487  F.second.ModTime)
488  return false;
489  }
490  return true;
491 }
492 
495  llvm::MemoryBuffer *MainFileBuffer) const {
496  PreambleBounds Bounds(PreambleBytes.size(), PreambleEndsAtStartOfLine);
497  configurePreamble(Bounds, CI, VFS, MainFileBuffer);
498 }
499 
502  llvm::MemoryBuffer *MainFileBuffer) const {
503  auto Bounds = ComputePreambleBounds(*CI.getLangOpts(), MainFileBuffer, 0);
504  configurePreamble(Bounds, CI, VFS, MainFileBuffer);
505 }
506 
508  PCHStorage Storage, std::vector<char> PreambleBytes,
509  bool PreambleEndsAtStartOfLine,
510  llvm::StringMap<PreambleFileHash> FilesInPreamble)
511  : Storage(std::move(Storage)), FilesInPreamble(std::move(FilesInPreamble)),
512  PreambleBytes(std::move(PreambleBytes)),
513  PreambleEndsAtStartOfLine(PreambleEndsAtStartOfLine) {
514  assert(this->Storage.getKind() != PCHStorage::Kind::Empty);
515 }
516 
517 llvm::ErrorOr<PrecompiledPreamble::TempPCHFile>
518 PrecompiledPreamble::TempPCHFile::CreateNewPreamblePCHFile() {
519  // FIXME: This is a hack so that we can override the preamble file during
520  // crash-recovery testing, which is the only case where the preamble files
521  // are not necessarily cleaned up.
522  const char *TmpFile = ::getenv("CINDEXTEST_PREAMBLE_FILE");
523  if (TmpFile)
524  return TempPCHFile::createFromCustomPath(TmpFile);
525  return TempPCHFile::createInSystemTempDir("preamble", "pch");
526 }
527 
528 llvm::ErrorOr<PrecompiledPreamble::TempPCHFile>
529 PrecompiledPreamble::TempPCHFile::createInSystemTempDir(const Twine &Prefix,
530  StringRef Suffix) {
532  // Using a version of createTemporaryFile with a file descriptor guarantees
533  // that we would never get a race condition in a multi-threaded setting
534  // (i.e., multiple threads getting the same temporary path).
535  int FD;
536  auto EC = llvm::sys::fs::createTemporaryFile(Prefix, Suffix, FD, File);
537  if (EC)
538  return EC;
539  // We only needed to make sure the file exists, close the file right away.
540  llvm::sys::Process::SafelyCloseFileDescriptor(FD);
541  return TempPCHFile(std::move(File).str());
542 }
543 
544 llvm::ErrorOr<PrecompiledPreamble::TempPCHFile>
545 PrecompiledPreamble::TempPCHFile::createFromCustomPath(const Twine &Path) {
546  return TempPCHFile(Path.str());
547 }
548 
549 PrecompiledPreamble::TempPCHFile::TempPCHFile(std::string FilePath)
550  : FilePath(std::move(FilePath)) {
551  TemporaryFiles::getInstance().addFile(*this->FilePath);
552 }
553 
554 PrecompiledPreamble::TempPCHFile::TempPCHFile(TempPCHFile &&Other) {
555  FilePath = std::move(Other.FilePath);
556  Other.FilePath = None;
557 }
558 
559 PrecompiledPreamble::TempPCHFile &PrecompiledPreamble::TempPCHFile::
560 operator=(TempPCHFile &&Other) {
561  RemoveFileIfPresent();
562 
563  FilePath = std::move(Other.FilePath);
564  Other.FilePath = None;
565  return *this;
566 }
567 
568 PrecompiledPreamble::TempPCHFile::~TempPCHFile() { RemoveFileIfPresent(); }
569 
570 void PrecompiledPreamble::TempPCHFile::RemoveFileIfPresent() {
571  if (FilePath) {
572  TemporaryFiles::getInstance().removeFile(*FilePath);
573  FilePath = None;
574  }
575 }
576 
577 llvm::StringRef PrecompiledPreamble::TempPCHFile::getFilePath() const {
578  assert(FilePath && "TempPCHFile doesn't have a FilePath. Had it been moved?");
579  return *FilePath;
580 }
581 
582 PrecompiledPreamble::PCHStorage::PCHStorage(TempPCHFile File)
583  : StorageKind(Kind::TempFile) {
584  new (&asFile()) TempPCHFile(std::move(File));
585 }
586 
587 PrecompiledPreamble::PCHStorage::PCHStorage(InMemoryPreamble Memory)
588  : StorageKind(Kind::InMemory) {
589  new (&asMemory()) InMemoryPreamble(std::move(Memory));
590 }
591 
592 PrecompiledPreamble::PCHStorage::PCHStorage(PCHStorage &&Other) : PCHStorage() {
593  *this = std::move(Other);
594 }
595 
596 PrecompiledPreamble::PCHStorage &PrecompiledPreamble::PCHStorage::
597 operator=(PCHStorage &&Other) {
598  destroy();
599 
600  StorageKind = Other.StorageKind;
601  switch (StorageKind) {
602  case Kind::Empty:
603  // do nothing;
604  break;
605  case Kind::TempFile:
606  new (&asFile()) TempPCHFile(std::move(Other.asFile()));
607  break;
608  case Kind::InMemory:
609  new (&asMemory()) InMemoryPreamble(std::move(Other.asMemory()));
610  break;
611  }
612 
613  Other.setEmpty();
614  return *this;
615 }
616 
617 PrecompiledPreamble::PCHStorage::~PCHStorage() { destroy(); }
618 
619 PrecompiledPreamble::PCHStorage::Kind
621  return StorageKind;
622 }
623 
624 PrecompiledPreamble::TempPCHFile &PrecompiledPreamble::PCHStorage::asFile() {
625  assert(getKind() == Kind::TempFile);
626  return *reinterpret_cast<TempPCHFile *>(Storage.buffer);
627 }
628 
629 const PrecompiledPreamble::TempPCHFile &
630 PrecompiledPreamble::PCHStorage::asFile() const {
631  return const_cast<PCHStorage *>(this)->asFile();
632 }
633 
634 PrecompiledPreamble::InMemoryPreamble &
635 PrecompiledPreamble::PCHStorage::asMemory() {
636  assert(getKind() == Kind::InMemory);
637  return *reinterpret_cast<InMemoryPreamble *>(Storage.buffer);
638 }
639 
640 const PrecompiledPreamble::InMemoryPreamble &
641 PrecompiledPreamble::PCHStorage::asMemory() const {
642  return const_cast<PCHStorage *>(this)->asMemory();
643 }
644 
645 void PrecompiledPreamble::PCHStorage::destroy() {
646  switch (StorageKind) {
647  case Kind::Empty:
648  return;
649  case Kind::TempFile:
650  asFile().~TempPCHFile();
651  return;
652  case Kind::InMemory:
653  asMemory().~InMemoryPreamble();
654  return;
655  }
656 }
657 
658 void PrecompiledPreamble::PCHStorage::setEmpty() {
659  destroy();
660  StorageKind = Kind::Empty;
661 }
662 
663 PrecompiledPreamble::PreambleFileHash
664 PrecompiledPreamble::PreambleFileHash::createForFile(off_t Size,
665  time_t ModTime) {
666  PreambleFileHash Result;
667  Result.Size = Size;
668  Result.ModTime = ModTime;
669  Result.MD5 = {};
670  return Result;
671 }
672 
673 PrecompiledPreamble::PreambleFileHash
674 PrecompiledPreamble::PreambleFileHash::createForMemoryBuffer(
675  const llvm::MemoryBuffer *Buffer) {
676  PreambleFileHash Result;
677  Result.Size = Buffer->getBufferSize();
678  Result.ModTime = 0;
679 
680  llvm::MD5 MD5Ctx;
681  MD5Ctx.update(Buffer->getBuffer().data());
682  MD5Ctx.final(Result.MD5);
683 
684  return Result;
685 }
686 
687 void PrecompiledPreamble::configurePreamble(
690  llvm::MemoryBuffer *MainFileBuffer) const {
691  assert(VFS);
692 
693  auto &PreprocessorOpts = CI.getPreprocessorOpts();
694 
695  // Remap main file to point to MainFileBuffer.
696  auto MainFilePath = CI.getFrontendOpts().Inputs[0].getFile();
697  PreprocessorOpts.addRemappedFile(MainFilePath, MainFileBuffer);
698 
699  // Configure ImpicitPCHInclude.
700  PreprocessorOpts.PrecompiledPreambleBytes.first = Bounds.Size;
701  PreprocessorOpts.PrecompiledPreambleBytes.second =
703  PreprocessorOpts.DisablePCHValidation = true;
704 
705  setupPreambleStorage(Storage, PreprocessorOpts, VFS);
706 }
707 
708 void PrecompiledPreamble::setupPreambleStorage(
709  const PCHStorage &Storage, PreprocessorOptions &PreprocessorOpts,
711  if (Storage.getKind() == PCHStorage::Kind::TempFile) {
712  const TempPCHFile &PCHFile = Storage.asFile();
713  PreprocessorOpts.ImplicitPCHInclude = PCHFile.getFilePath();
714 
715  // Make sure we can access the PCH file even if we're using a VFS
717  llvm::vfs::getRealFileSystem();
718  auto PCHPath = PCHFile.getFilePath();
719  if (VFS == RealFS || VFS->exists(PCHPath))
720  return;
721  auto Buf = RealFS->getBufferForFile(PCHPath);
722  if (!Buf) {
723  // We can't read the file even from RealFS, this is clearly an error,
724  // but we'll just leave the current VFS as is and let clang's code
725  // figure out what to do with missing PCH.
726  return;
727  }
728 
729  // We have a slight inconsistency here -- we're using the VFS to
730  // read files, but the PCH was generated in the real file system.
731  VFS = createVFSOverlayForPreamblePCH(PCHPath, std::move(*Buf), VFS);
732  } else {
733  assert(Storage.getKind() == PCHStorage::Kind::InMemory);
734  // For in-memory preamble, we have to provide a VFS overlay that makes it
735  // accessible.
736  StringRef PCHPath = getInMemoryPreamblePath();
737  PreprocessorOpts.ImplicitPCHInclude = PCHPath;
738 
739  auto Buf = llvm::MemoryBuffer::getMemBuffer(Storage.asMemory().Data);
740  VFS = createVFSOverlayForPreamblePCH(PCHPath, std::move(Buf), VFS);
741  }
742 }
743 
748 std::unique_ptr<PPCallbacks> PreambleCallbacks::createPPCallbacks() {
749  return nullptr;
750 }
752 
753 static llvm::ManagedStatic<BuildPreambleErrorCategory> BuildPreambleErrCategory;
754 
756  return std::error_code(static_cast<int>(Error), *BuildPreambleErrCategory);
757 }
758 
759 const char *BuildPreambleErrorCategory::name() const noexcept {
760  return "build-preamble.error";
761 }
762 
763 std::string BuildPreambleErrorCategory::message(int condition) const {
764  switch (static_cast<BuildPreambleError>(condition)) {
766  return "Could not create temporary file for PCH";
768  return "CreateTargetInfo() return null";
770  return "BeginSourceFile() return an error";
772  return "Could not emit PCH";
773  }
774  llvm_unreachable("unexpected BuildPreambleError");
775 }
std::size_t getSize() const
Returns the size, in bytes, that preamble takes on disk or in memory.
Describes the bounds (start, size) of the preamble and a flag required by PreprocessorOptions::Precom...
Definition: Lexer.h:58
Implements support for file system lookup, file system caching, and directory search management...
Definition: FileManager.h:116
__SIZE_TYPE__ size_t
The unsigned integer type of the result of the sizeof operator.
Definition: opencl-c.h:67
time_t getModificationTime() const
Definition: FileManager.h:89
bool CanReuse(const CompilerInvocation &Invocation, const llvm::MemoryBuffer *MainFileBuffer, PreambleBounds Bounds, llvm::vfs::FileSystem *VFS) const
Check whether PrecompiledPreamble can be reused for the new contents(MainFileBuffer) of the main file...
An interface for collecting the dependencies of a compilation.
Definition: Utils.h:82
The translation unit is a prefix to a translation unit, and is not complete.
Definition: LangOptions.h:367
InMemoryModuleCache & getModuleCache() const
PreprocessorOptions - This class is used for passing the various options used in preprocessor initial...
void addRemappedFile(StringRef From, StringRef To)
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:154
void HandleTranslationUnit(ASTContext &Ctx) override
HandleTranslationUnit - This method is called when the ASTs for entire translation unit have been par...
Definition: GeneratePCH.cpp:41
Definition: Format.h:2118
static bool moveOnNoError(llvm::ErrorOr< T > Val, T &Output)
Definition: ASTUnit.cpp:146
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
unsigned RelocatablePCH
When generating PCH files, instruct the AST writer to create relocatable PCH files.
static bool ComputeASTConsumerArguments(CompilerInstance &CI, std::string &Sysroot)
Compute the AST consumer arguments that will be used to create the PCHGenerator instance returned by ...
static llvm::ManagedStatic< BuildPreambleErrorCategory > BuildPreambleErrCategory
std::error_code make_error_code(BuildPreambleError Error)
FrontendOptions & getFrontendOpts()
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:148
bool RetainRemappedFileBuffers
Whether the compiler instance should retain (i.e., not free) the buffers associated with remapped fil...
void OverridePreamble(CompilerInvocation &CI, IntrusiveRefCntPtr< llvm::vfs::FileSystem > &VFS, llvm::MemoryBuffer *MainFileBuffer) const
Configure CI to use this preamble.
void Reset()
Reset the state of the diagnostic object to its initial configuration.
Definition: Diagnostic.cpp:121
FrontendOptions & getFrontendOpts()
bool PreambleEndsAtStartOfLine
Whether the preamble ends at the start of a new line.
Definition: Lexer.h:66
A set of callbacks to gather useful information while building a preamble.
return Out str()
StringRef Filename
Definition: Format.cpp:1667
const char * name() const noexcept override
PreambleBounds getBounds() const
PreambleBounds used to build the preamble.
void AddImplicitPreamble(CompilerInvocation &CI, IntrusiveRefCntPtr< llvm::vfs::FileSystem > &VFS, llvm::MemoryBuffer *MainFileBuffer) const
Changes options inside CI to use PCH from this preamble.
static PreambleBounds ComputePreamble(StringRef Buffer, const LangOptions &LangOpts, unsigned MaxLines=0)
Compute the preamble of the given file.
Definition: Lexer.cpp:573
const FileEntry * getFileEntryForID(FileID FID) const
Returns the FileEntry record for the provided FileID.
Defines the clang::Preprocessor interface.
static TargetInfo * CreateTargetInfo(DiagnosticsEngine &Diags, const std::shared_ptr< TargetOptions > &Opts)
Construct a target for the given options.
Definition: Targets.cpp:611
bool GeneratePreamble
True indicates that a preamble is being generated.
PreambleBounds ComputePreambleBounds(const LangOptions &LangOpts, llvm::MemoryBuffer *Buffer, unsigned MaxLines)
Runs lexer to compute suggested preamble bounds.
The result type of a method or function.
In-memory cache for modules.
CompilerInstance - Helper class for managing a single instance of the Clang compiler.
StringRef getName() const
Definition: FileManager.h:83
virtual CommentHandler * getCommentHandler()
The returned CommentHandler will be added to the preprocessor if not null.
std::string ImplicitPCHInclude
The implicit PCH included at the start of the translation unit, or empty.
LLVM IR: we accept this so that we can run the optimizer on it, and compile it to assembly or object ...
std::vector< FrontendInputFile > Inputs
The input files and their types.
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:59
void ProcessWarningOptions(DiagnosticsEngine &Diags, const DiagnosticOptions &Opts, bool ReportDiags=true)
ProcessWarningOptions - Initialize the diagnostic client and process the warning options specified on...
Definition: Warnings.cpp:43
Abstract base class to use for AST consumer-based frontend actions.
virtual void BeforeExecute(CompilerInstance &CI)
Called before FrontendAction::BeginSourceFile.
virtual void AfterPCHEmitted(ASTWriter &Writer)
Called after PCH has been emitted.
llvm::MemoryBuffer * getMemoryBufferForFile(const FileEntry *File, bool *Invalid=nullptr)
Retrieve the memory buffer associated with the given file.
PrecompiledPreamble(PrecompiledPreamble &&)=default
std::string message(int condition) const override
Dataflow Directional Tag Classes.
A class holding a PCH and all information to check whether it is valid to reuse the PCH for the subse...
PreprocessorOptions & getPreprocessorOpts()
off_t getSize() const
Definition: FileManager.h:86
IntrusiveRefCntPtr< llvm::vfs::FileSystem > createVFSFromCompilerInvocation(const CompilerInvocation &CI, DiagnosticsEngine &Diags)
FileID getMainFileID() const
Returns the FileID of the main source file.
Helper class for holding the data necessary to invoke the compiler.
FrontendOptions - Options for controlling the behavior of the frontend.
virtual void AfterExecute(CompilerInstance &CI)
Called after FrontendAction::Execute(), but before FrontendAction::EndSourceFile().
static llvm::ErrorOr< PrecompiledPreamble > Build(const CompilerInvocation &Invocation, const llvm::MemoryBuffer *MainFileBuffer, PreambleBounds Bounds, DiagnosticsEngine &Diagnostics, IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS, std::shared_ptr< PCHContainerOperations > PCHContainerOps, bool StoreInMemory, PreambleCallbacks &Callbacks)
Try to build PrecompiledPreamble for Invocation.
Indicates that the tracking object is a descendant of a referenced-counted OSObject, used in the Darwin kernel.
unsigned Size
Size of the preamble in bytes.
Definition: Lexer.h:60
Generate pre-compiled header.
Preprocessor & getPreprocessor() const
Return the current preprocessor.
TranslationUnitKind
Describes the kind of translation unit being processed.
Definition: LangOptions.h:361
Writes an AST file containing the contents of a translation unit.
Definition: ASTWriter.h:103
std::pair< unsigned, bool > PrecompiledPreambleBytes
If non-zero, the implicit PCH include is actually a precompiled preamble that covers this number of b...
Defines the clang::TargetInfo interface.
__DEVICE__ int max(int __a, int __b)
static Decl::Kind getKind(const Decl *D)
Definition: DeclBase.cpp:957
Abstract base class that describes a handler that will receive source ranges for each of the comments...
An abstract superclass that describes a custom extension to the module/precompiled header file format...
AST and semantic-analysis consumer that generates a precompiled header from the parsed source code...
Definition: ASTWriter.h:969
static std::unique_ptr< llvm::raw_pwrite_stream > CreateOutputFile(CompilerInstance &CI, StringRef InFile, std::string &OutputFile)
Creates file to write the PCH into and returns a stream to write it into.
#define true
Definition: stdbool.h:32
virtual void HandleTopLevelDecl(DeclGroupRef DG)
Called for each TopLevelDecl.
This class handles loading and caching of source files into memory.
virtual std::unique_ptr< PPCallbacks > createPPCallbacks()
Creates wrapper class for PPCallbacks so we can also process information about includes that are insi...
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:123