1//===--- PPLexerChange.cpp - Handle changing lexers in the preprocessor ---===//
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// This file implements pieces of the Preprocessor interface that manage the
10// current lexer stack.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Basic/FileManager.h"
15#include "clang/Basic/SourceManager.h"
16#include "clang/Lex/HeaderSearch.h"
17#include "clang/Lex/LexDiagnostic.h"
18#include "clang/Lex/MacroInfo.h"
19#include "clang/Lex/Preprocessor.h"
20#include "clang/Lex/PreprocessorOptions.h"
21#include "llvm/ADT/StringSwitch.h"
22#include "llvm/Support/FileSystem.h"
23#include "llvm/Support/MemoryBufferRef.h"
24#include "llvm/Support/Path.h"
25#include <optional>
26
27using namespace clang;
28
29//===----------------------------------------------------------------------===//
30// Miscellaneous Methods.
31//===----------------------------------------------------------------------===//
32
33/// isInPrimaryFile - Return true if we're in the top-level file, not in a
34/// \#include.  This looks through macro expansions and active _Pragma lexers.
35bool Preprocessor::isInPrimaryFile() const {
36  if (IsFileLexer())
37    return IncludeMacroStack.empty();
38
39  // If there are any stacked lexers, we're in a #include.
40  assert(IsFileLexer(IncludeMacroStack[0]) &&
41         "Top level include stack isn't our primary lexer?");
42  return llvm::none_of(
43      llvm::drop_begin(IncludeMacroStack),
44      [&](const IncludeStackInfo &ISI) -> bool { return IsFileLexer(ISI); });
45}
46
47/// getCurrentLexer - Return the current file lexer being lexed from.  Note
48/// that this ignores any potentially active macro expansions and _Pragma
49/// expansions going on at the time.
50PreprocessorLexer *Preprocessor::getCurrentFileLexer() const {
51  if (IsFileLexer())
52    return CurPPLexer;
53
54  // Look for a stacked lexer.
55  for (const IncludeStackInfo &ISI : llvm::reverse(IncludeMacroStack)) {
56    if (IsFileLexer(ISI))
57      return ISI.ThePPLexer;
58  }
59  return nullptr;
60}
61
62
63//===----------------------------------------------------------------------===//
64// Methods for Entering and Callbacks for leaving various contexts
65//===----------------------------------------------------------------------===//
66
67/// EnterSourceFile - Add a source file to the top of the include stack and
68/// start lexing tokens from it instead of the current buffer.
69bool Preprocessor::EnterSourceFile(FileID FID, ConstSearchDirIterator CurDir,
70                                   SourceLocation Loc,
71                                   bool IsFirstIncludeOfFile) {
72  assert(!CurTokenLexer && "Cannot #include a file inside a macro!");
73  ++NumEnteredSourceFiles;
74
75  if (MaxIncludeStackDepth < IncludeMacroStack.size())
76    MaxIncludeStackDepth = IncludeMacroStack.size();
77
78  // Get the MemoryBuffer for this FID, if it fails, we fail.
79  std::optional<llvm::MemoryBufferRef> InputFile =
80      getSourceManager().getBufferOrNone(FID, Loc);
81  if (!InputFile) {
82    SourceLocation FileStart = SourceMgr.getLocForStartOfFile(FID);
83    Diag(Loc, diag::err_pp_error_opening_file)
84        << std::string(SourceMgr.getBufferName(FileStart)) << "";
85    return true;
86  }
87
88  if (isCodeCompletionEnabled() &&
89      SourceMgr.getFileEntryForID(FID) == CodeCompletionFile) {
90    CodeCompletionFileLoc = SourceMgr.getLocForStartOfFile(FID);
91    CodeCompletionLoc =
92        CodeCompletionFileLoc.getLocWithOffset(CodeCompletionOffset);
93  }
94
95  Lexer *TheLexer = new Lexer(FID, *InputFile, *this, IsFirstIncludeOfFile);
96  if (getPreprocessorOpts().DependencyDirectivesForFile &&
97      FID != PredefinesFileID) {
98    if (OptionalFileEntryRef File = SourceMgr.getFileEntryRefForID(FID)) {
99      if (std::optional<ArrayRef<dependency_directives_scan::Directive>>
100              DepDirectives =
101                  getPreprocessorOpts().DependencyDirectivesForFile(*File)) {
102        TheLexer->DepDirectives = *DepDirectives;
103      }
104    }
105  }
106
107  EnterSourceFileWithLexer(TheLexer, CurDir);
108  return false;
109}
110
111/// EnterSourceFileWithLexer - Add a source file to the top of the include stack
112///  and start lexing tokens from it instead of the current buffer.
113void Preprocessor::EnterSourceFileWithLexer(Lexer *TheLexer,
114                                            ConstSearchDirIterator CurDir) {
115  PreprocessorLexer *PrevPPLexer = CurPPLexer;
116
117  // Add the current lexer to the include stack.
118  if (CurPPLexer || CurTokenLexer)
119    PushIncludeMacroStack();
120
121  CurLexer.reset(TheLexer);
122  CurPPLexer = TheLexer;
123  CurDirLookup = CurDir;
124  CurLexerSubmodule = nullptr;
125  if (CurLexerCallback != CLK_LexAfterModuleImport)
126    CurLexerCallback = TheLexer->isDependencyDirectivesLexer()
127                           ? CLK_DependencyDirectivesLexer
128                           : CLK_Lexer;
129
130  // Notify the client, if desired, that we are in a new source file.
131  if (Callbacks && !CurLexer->Is_PragmaLexer) {
132    SrcMgr::CharacteristicKind FileType =
133       SourceMgr.getFileCharacteristic(CurLexer->getFileLoc());
134
135    FileID PrevFID;
136    SourceLocation EnterLoc;
137    if (PrevPPLexer) {
138      PrevFID = PrevPPLexer->getFileID();
139      EnterLoc = PrevPPLexer->getSourceLocation();
140    }
141    Callbacks->FileChanged(CurLexer->getFileLoc(), PPCallbacks::EnterFile,
142                           FileType, PrevFID);
143    Callbacks->LexedFileChanged(CurLexer->getFileID(),
144                                PPCallbacks::LexedFileChangeReason::EnterFile,
145                                FileType, PrevFID, EnterLoc);
146  }
147}
148
149/// EnterMacro - Add a Macro to the top of the include stack and start lexing
150/// tokens from it instead of the current buffer.
151void Preprocessor::EnterMacro(Token &Tok, SourceLocation ILEnd,
152                              MacroInfo *Macro, MacroArgs *Args) {
153  std::unique_ptr<TokenLexer> TokLexer;
154  if (NumCachedTokenLexers == 0) {
155    TokLexer = std::make_unique<TokenLexer>(Tok, ILEnd, Macro, Args, *this);
156  } else {
157    TokLexer = std::move(TokenLexerCache[--NumCachedTokenLexers]);
158    TokLexer->Init(Tok, ILEnd, Macro, Args);
159  }
160
161  PushIncludeMacroStack();
162  CurDirLookup = nullptr;
163  CurTokenLexer = std::move(TokLexer);
164  if (CurLexerCallback != CLK_LexAfterModuleImport)
165    CurLexerCallback = CLK_TokenLexer;
166}
167
168/// EnterTokenStream - Add a "macro" context to the top of the include stack,
169/// which will cause the lexer to start returning the specified tokens.
170///
171/// If DisableMacroExpansion is true, tokens lexed from the token stream will
172/// not be subject to further macro expansion.  Otherwise, these tokens will
173/// be re-macro-expanded when/if expansion is enabled.
174///
175/// If OwnsTokens is false, this method assumes that the specified stream of
176/// tokens has a permanent owner somewhere, so they do not need to be copied.
177/// If it is true, it assumes the array of tokens is allocated with new[] and
178/// must be freed.
179///
180void Preprocessor::EnterTokenStream(const Token *Toks, unsigned NumToks,
181                                    bool DisableMacroExpansion, bool OwnsTokens,
182                                    bool IsReinject) {
183  if (CurLexerCallback == CLK_CachingLexer) {
184    if (CachedLexPos < CachedTokens.size()) {
185      assert(IsReinject && "new tokens in the middle of cached stream");
186      // We're entering tokens into the middle of our cached token stream. We
187      // can't represent that, so just insert the tokens into the buffer.
188      CachedTokens.insert(CachedTokens.begin() + CachedLexPos,
189                          Toks, Toks + NumToks);
190      if (OwnsTokens)
191        delete [] Toks;
192      return;
193    }
194
195    // New tokens are at the end of the cached token sequnece; insert the
196    // token stream underneath the caching lexer.
197    ExitCachingLexMode();
198    EnterTokenStream(Toks, NumToks, DisableMacroExpansion, OwnsTokens,
199                     IsReinject);
200    EnterCachingLexMode();
201    return;
202  }
203
204  // Create a macro expander to expand from the specified token stream.
205  std::unique_ptr<TokenLexer> TokLexer;
206  if (NumCachedTokenLexers == 0) {
207    TokLexer = std::make_unique<TokenLexer>(
208        Toks, NumToks, DisableMacroExpansion, OwnsTokens, IsReinject, *this);
209  } else {
210    TokLexer = std::move(TokenLexerCache[--NumCachedTokenLexers]);
211    TokLexer->Init(Toks, NumToks, DisableMacroExpansion, OwnsTokens,
212                   IsReinject);
213  }
214
215  // Save our current state.
216  PushIncludeMacroStack();
217  CurDirLookup = nullptr;
218  CurTokenLexer = std::move(TokLexer);
219  if (CurLexerCallback != CLK_LexAfterModuleImport)
220    CurLexerCallback = CLK_TokenLexer;
221}
222
223/// Compute the relative path that names the given file relative to
224/// the given directory.
225static void computeRelativePath(FileManager &FM, const DirectoryEntry *Dir,
226                                FileEntryRef File, SmallString<128> &Result) {
227  Result.clear();
228
229  StringRef FilePath = File.getDir().getName();
230  StringRef Path = FilePath;
231  while (!Path.empty()) {
232    if (auto CurDir = FM.getDirectory(Path)) {
233      if (*CurDir == Dir) {
234        Result = FilePath.substr(Path.size());
235        llvm::sys::path::append(Result,
236                                llvm::sys::path::filename(File.getName()));
237        return;
238      }
239    }
240
241    Path = llvm::sys::path::parent_path(Path);
242  }
243
244  Result = File.getName();
245}
246
247void Preprocessor::PropagateLineStartLeadingSpaceInfo(Token &Result) {
248  if (CurTokenLexer) {
249    CurTokenLexer->PropagateLineStartLeadingSpaceInfo(Result);
250    return;
251  }
252  if (CurLexer) {
253    CurLexer->PropagateLineStartLeadingSpaceInfo(Result);
254    return;
255  }
256  // FIXME: Handle other kinds of lexers?  It generally shouldn't matter,
257  // but it might if they're empty?
258}
259
260/// Determine the location to use as the end of the buffer for a lexer.
261///
262/// If the file ends with a newline, form the EOF token on the newline itself,
263/// rather than "on the line following it", which doesn't exist.  This makes
264/// diagnostics relating to the end of file include the last file that the user
265/// actually typed, which is goodness.
266const char *Preprocessor::getCurLexerEndPos() {
267  const char *EndPos = CurLexer->BufferEnd;
268  if (EndPos != CurLexer->BufferStart &&
269      (EndPos[-1] == '\n' || EndPos[-1] == '\r')) {
270    --EndPos;
271
272    // Handle \n\r and \r\n:
273    if (EndPos != CurLexer->BufferStart &&
274        (EndPos[-1] == '\n' || EndPos[-1] == '\r') &&
275        EndPos[-1] != EndPos[0])
276      --EndPos;
277  }
278
279  return EndPos;
280}
281
282static void collectAllSubModulesWithUmbrellaHeader(
283    const Module &Mod, SmallVectorImpl<const Module *> &SubMods) {
284  if (Mod.getUmbrellaHeaderAsWritten())
285    SubMods.push_back(&Mod);
286  for (auto *M : Mod.submodules())
287    collectAllSubModulesWithUmbrellaHeader(*M, SubMods);
288}
289
290void Preprocessor::diagnoseMissingHeaderInUmbrellaDir(const Module &Mod) {
291  std::optional<Module::Header> UmbrellaHeader =
292      Mod.getUmbrellaHeaderAsWritten();
293  assert(UmbrellaHeader && "Module must use umbrella header");
294  const FileID &File = SourceMgr.translateFile(UmbrellaHeader->Entry);
295  SourceLocation ExpectedHeadersLoc = SourceMgr.getLocForEndOfFile(File);
296  if (getDiagnostics().isIgnored(diag::warn_uncovered_module_header,
297                                 ExpectedHeadersLoc))
298    return;
299
300  ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
301  OptionalDirectoryEntryRef Dir = Mod.getEffectiveUmbrellaDir();
302  llvm::vfs::FileSystem &FS = FileMgr.getVirtualFileSystem();
303  std::error_code EC;
304  for (llvm::vfs::recursive_directory_iterator Entry(FS, Dir->getName(), EC),
305       End;
306       Entry != End && !EC; Entry.increment(EC)) {
307    using llvm::StringSwitch;
308
309    // Check whether this entry has an extension typically associated with
310    // headers.
311    if (!StringSwitch<bool>(llvm::sys::path::extension(Entry->path()))
312             .Cases(".h", ".H", ".hh", ".hpp", true)
313             .Default(false))
314      continue;
315
316    if (auto Header = getFileManager().getOptionalFileRef(Entry->path()))
317      if (!getSourceManager().hasFileInfo(*Header)) {
318        if (!ModMap.isHeaderInUnavailableModule(*Header)) {
319          // Find the relative path that would access this header.
320          SmallString<128> RelativePath;
321          computeRelativePath(FileMgr, *Dir, *Header, RelativePath);
322          Diag(ExpectedHeadersLoc, diag::warn_uncovered_module_header)
323              << Mod.getFullModuleName() << RelativePath;
324        }
325      }
326  }
327}
328
329/// HandleEndOfFile - This callback is invoked when the lexer hits the end of
330/// the current file.  This either returns the EOF token or pops a level off
331/// the include stack and keeps going.
332bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) {
333  assert(!CurTokenLexer &&
334         "Ending a file when currently in a macro!");
335
336  SourceLocation UnclosedSafeBufferOptOutLoc;
337
338  if (IncludeMacroStack.empty() &&
339      isPPInSafeBufferOptOutRegion(UnclosedSafeBufferOptOutLoc)) {
340    // To warn if a "-Wunsafe-buffer-usage" opt-out region is still open by the
341    // end of a file.
342    Diag(UnclosedSafeBufferOptOutLoc,
343         diag::err_pp_unclosed_pragma_unsafe_buffer_usage);
344  }
345  // If we have an unclosed module region from a pragma at the end of a
346  // module, complain and close it now.
347  const bool LeavingSubmodule = CurLexer && CurLexerSubmodule;
348  if ((LeavingSubmodule || IncludeMacroStack.empty()) &&
349      !BuildingSubmoduleStack.empty() &&
350      BuildingSubmoduleStack.back().IsPragma) {
351    Diag(BuildingSubmoduleStack.back().ImportLoc,
352         diag::err_pp_module_begin_without_module_end);
353    Module *M = LeaveSubmodule(/*ForPragma*/true);
354
355    Result.startToken();
356    const char *EndPos = getCurLexerEndPos();
357    CurLexer->BufferPtr = EndPos;
358    CurLexer->FormTokenWithChars(Result, EndPos, tok::annot_module_end);
359    Result.setAnnotationEndLoc(Result.getLocation());
360    Result.setAnnotationValue(M);
361    return true;
362  }
363
364  // See if this file had a controlling macro.
365  if (CurPPLexer) {  // Not ending a macro, ignore it.
366    if (const IdentifierInfo *ControllingMacro =
367          CurPPLexer->MIOpt.GetControllingMacroAtEndOfFile()) {
368      // Okay, this has a controlling macro, remember in HeaderFileInfo.
369      if (OptionalFileEntryRef FE = CurPPLexer->getFileEntry()) {
370        HeaderInfo.SetFileControllingMacro(*FE, ControllingMacro);
371        if (MacroInfo *MI =
372              getMacroInfo(const_cast<IdentifierInfo*>(ControllingMacro)))
373          MI->setUsedForHeaderGuard(true);
374        if (const IdentifierInfo *DefinedMacro =
375              CurPPLexer->MIOpt.GetDefinedMacro()) {
376          if (!isMacroDefined(ControllingMacro) &&
377              DefinedMacro != ControllingMacro &&
378              CurLexer->isFirstTimeLexingFile()) {
379
380            // If the edit distance between the two macros is more than 50%,
381            // DefinedMacro may not be header guard, or can be header guard of
382            // another header file. Therefore, it maybe defining something
383            // completely different. This can be observed in the wild when
384            // handling feature macros or header guards in different files.
385
386            const StringRef ControllingMacroName = ControllingMacro->getName();
387            const StringRef DefinedMacroName = DefinedMacro->getName();
388            const size_t MaxHalfLength = std::max(ControllingMacroName.size(),
389                                                  DefinedMacroName.size()) / 2;
390            const unsigned ED = ControllingMacroName.edit_distance(
391                DefinedMacroName, true, MaxHalfLength);
392            if (ED <= MaxHalfLength) {
393              // Emit a warning for a bad header guard.
394              Diag(CurPPLexer->MIOpt.GetMacroLocation(),
395                   diag::warn_header_guard)
396                  << CurPPLexer->MIOpt.GetMacroLocation() << ControllingMacro;
397              Diag(CurPPLexer->MIOpt.GetDefinedLocation(),
398                   diag::note_header_guard)
399                  << CurPPLexer->MIOpt.GetDefinedLocation() << DefinedMacro
400                  << ControllingMacro
401                  << FixItHint::CreateReplacement(
402                         CurPPLexer->MIOpt.GetDefinedLocation(),
403                         ControllingMacro->getName());
404            }
405          }
406        }
407      }
408    }
409  }
410
411  // Complain about reaching a true EOF within arc_cf_code_audited.
412  // We don't want to complain about reaching the end of a macro
413  // instantiation or a _Pragma.
414  if (PragmaARCCFCodeAuditedInfo.second.isValid() && !isEndOfMacro &&
415      !(CurLexer && CurLexer->Is_PragmaLexer)) {
416    Diag(PragmaARCCFCodeAuditedInfo.second,
417         diag::err_pp_eof_in_arc_cf_code_audited);
418
419    // Recover by leaving immediately.
420    PragmaARCCFCodeAuditedInfo = {nullptr, SourceLocation()};
421  }
422
423  // Complain about reaching a true EOF within assume_nonnull.
424  // We don't want to complain about reaching the end of a macro
425  // instantiation or a _Pragma.
426  if (PragmaAssumeNonNullLoc.isValid() &&
427      !isEndOfMacro && !(CurLexer && CurLexer->Is_PragmaLexer)) {
428    // If we're at the end of generating a preamble, we should record the
429    // unterminated \#pragma clang assume_nonnull so we can restore it later
430    // when the preamble is loaded into the main file.
431    if (isRecordingPreamble() && isInPrimaryFile())
432      PreambleRecordedPragmaAssumeNonNullLoc = PragmaAssumeNonNullLoc;
433    else
434      Diag(PragmaAssumeNonNullLoc, diag::err_pp_eof_in_assume_nonnull);
435    // Recover by leaving immediately.
436    PragmaAssumeNonNullLoc = SourceLocation();
437  }
438
439  bool LeavingPCHThroughHeader = false;
440
441  // If this is a #include'd file, pop it off the include stack and continue
442  // lexing the #includer file.
443  if (!IncludeMacroStack.empty()) {
444
445    // If we lexed the code-completion file, act as if we reached EOF.
446    if (isCodeCompletionEnabled() && CurPPLexer &&
447        SourceMgr.getLocForStartOfFile(CurPPLexer->getFileID()) ==
448            CodeCompletionFileLoc) {
449      assert(CurLexer && "Got EOF but no current lexer set!");
450      Result.startToken();
451      CurLexer->FormTokenWithChars(Result, CurLexer->BufferEnd, tok::eof);
452      CurLexer.reset();
453
454      CurPPLexer = nullptr;
455      recomputeCurLexerKind();
456      return true;
457    }
458
459    if (!isEndOfMacro && CurPPLexer &&
460        (SourceMgr.getIncludeLoc(CurPPLexer->getFileID()).isValid() ||
461         // Predefines file doesn't have a valid include location.
462         (PredefinesFileID.isValid() &&
463          CurPPLexer->getFileID() == PredefinesFileID))) {
464      // Notify SourceManager to record the number of FileIDs that were created
465      // during lexing of the #include'd file.
466      unsigned NumFIDs =
467          SourceMgr.local_sloc_entry_size() -
468          CurPPLexer->getInitialNumSLocEntries() + 1/*#include'd file*/;
469      SourceMgr.setNumCreatedFIDsForFileID(CurPPLexer->getFileID(), NumFIDs);
470    }
471
472    bool ExitedFromPredefinesFile = false;
473    FileID ExitedFID;
474    if (!isEndOfMacro && CurPPLexer) {
475      ExitedFID = CurPPLexer->getFileID();
476
477      assert(PredefinesFileID.isValid() &&
478             "HandleEndOfFile is called before PredefinesFileId is set");
479      ExitedFromPredefinesFile = (PredefinesFileID == ExitedFID);
480    }
481
482    if (LeavingSubmodule) {
483      // We're done with this submodule.
484      Module *M = LeaveSubmodule(/*ForPragma*/false);
485
486      // Notify the parser that we've left the module.
487      const char *EndPos = getCurLexerEndPos();
488      Result.startToken();
489      CurLexer->BufferPtr = EndPos;
490      CurLexer->FormTokenWithChars(Result, EndPos, tok::annot_module_end);
491      Result.setAnnotationEndLoc(Result.getLocation());
492      Result.setAnnotationValue(M);
493    }
494
495    bool FoundPCHThroughHeader = false;
496    if (CurPPLexer && creatingPCHWithThroughHeader() &&
497        isPCHThroughHeader(
498            SourceMgr.getFileEntryForID(CurPPLexer->getFileID())))
499      FoundPCHThroughHeader = true;
500
501    // We're done with the #included file.
502    RemoveTopOfLexerStack();
503
504    // Propagate info about start-of-line/leading white-space/etc.
505    PropagateLineStartLeadingSpaceInfo(Result);
506
507    // Notify the client, if desired, that we are in a new source file.
508    if (Callbacks && !isEndOfMacro && CurPPLexer) {
509      SourceLocation Loc = CurPPLexer->getSourceLocation();
510      SrcMgr::CharacteristicKind FileType =
511          SourceMgr.getFileCharacteristic(Loc);
512      Callbacks->FileChanged(Loc, PPCallbacks::ExitFile, FileType, ExitedFID);
513      Callbacks->LexedFileChanged(CurPPLexer->getFileID(),
514                                  PPCallbacks::LexedFileChangeReason::ExitFile,
515                                  FileType, ExitedFID, Loc);
516    }
517
518    // Restore conditional stack as well as the recorded
519    // \#pragma clang assume_nonnull from the preamble right after exiting
520    // from the predefines file.
521    if (ExitedFromPredefinesFile) {
522      replayPreambleConditionalStack();
523      if (PreambleRecordedPragmaAssumeNonNullLoc.isValid())
524        PragmaAssumeNonNullLoc = PreambleRecordedPragmaAssumeNonNullLoc;
525    }
526
527    if (!isEndOfMacro && CurPPLexer && FoundPCHThroughHeader &&
528        (isInPrimaryFile() ||
529         CurPPLexer->getFileID() == getPredefinesFileID())) {
530      // Leaving the through header. Continue directly to end of main file
531      // processing.
532      LeavingPCHThroughHeader = true;
533    } else {
534      // Client should lex another token unless we generated an EOM.
535      return LeavingSubmodule;
536    }
537  }
538  // If this is the end of the main file, form an EOF token.
539  assert(CurLexer && "Got EOF but no current lexer set!");
540  const char *EndPos = getCurLexerEndPos();
541  Result.startToken();
542  CurLexer->BufferPtr = EndPos;
543
544  if (getLangOpts().IncrementalExtensions) {
545    CurLexer->FormTokenWithChars(Result, EndPos, tok::annot_repl_input_end);
546    Result.setAnnotationEndLoc(Result.getLocation());
547    Result.setAnnotationValue(nullptr);
548  } else {
549    CurLexer->FormTokenWithChars(Result, EndPos, tok::eof);
550  }
551
552  if (isCodeCompletionEnabled()) {
553    // Inserting the code-completion point increases the source buffer by 1,
554    // but the main FileID was created before inserting the point.
555    // Compensate by reducing the EOF location by 1, otherwise the location
556    // will point to the next FileID.
557    // FIXME: This is hacky, the code-completion point should probably be
558    // inserted before the main FileID is created.
559    if (CurLexer->getFileLoc() == CodeCompletionFileLoc)
560      Result.setLocation(Result.getLocation().getLocWithOffset(-1));
561  }
562
563  if (creatingPCHWithThroughHeader() && !LeavingPCHThroughHeader) {
564    // Reached the end of the compilation without finding the through header.
565    Diag(CurLexer->getFileLoc(), diag::err_pp_through_header_not_seen)
566        << PPOpts->PCHThroughHeader << 0;
567  }
568
569  if (!isIncrementalProcessingEnabled())
570    // We're done with lexing.
571    CurLexer.reset();
572
573  if (!isIncrementalProcessingEnabled())
574    CurPPLexer = nullptr;
575
576  if (TUKind == TU_Complete) {
577    // This is the end of the top-level file. 'WarnUnusedMacroLocs' has
578    // collected all macro locations that we need to warn because they are not
579    // used.
580    for (WarnUnusedMacroLocsTy::iterator
581           I=WarnUnusedMacroLocs.begin(), E=WarnUnusedMacroLocs.end();
582           I!=E; ++I)
583      Diag(*I, diag::pp_macro_not_used);
584  }
585
586  // If we are building a module that has an umbrella header, make sure that
587  // each of the headers within the directory, including all submodules, is
588  // covered by the umbrella header was actually included by the umbrella
589  // header.
590  if (Module *Mod = getCurrentModule()) {
591    llvm::SmallVector<const Module *, 4> AllMods;
592    collectAllSubModulesWithUmbrellaHeader(*Mod, AllMods);
593    for (auto *M : AllMods)
594      diagnoseMissingHeaderInUmbrellaDir(*M);
595  }
596
597  return true;
598}
599
600/// HandleEndOfTokenLexer - This callback is invoked when the current TokenLexer
601/// hits the end of its token stream.
602bool Preprocessor::HandleEndOfTokenLexer(Token &Result) {
603  assert(CurTokenLexer && !CurPPLexer &&
604         "Ending a macro when currently in a #include file!");
605
606  if (!MacroExpandingLexersStack.empty() &&
607      MacroExpandingLexersStack.back().first == CurTokenLexer.get())
608    removeCachedMacroExpandedTokensOfLastLexer();
609
610  // Delete or cache the now-dead macro expander.
611  if (NumCachedTokenLexers == TokenLexerCacheSize)
612    CurTokenLexer.reset();
613  else
614    TokenLexerCache[NumCachedTokenLexers++] = std::move(CurTokenLexer);
615
616  // Handle this like a #include file being popped off the stack.
617  return HandleEndOfFile(Result, true);
618}
619
620/// RemoveTopOfLexerStack - Pop the current lexer/macro exp off the top of the
621/// lexer stack.  This should only be used in situations where the current
622/// state of the top-of-stack lexer is unknown.
623void Preprocessor::RemoveTopOfLexerStack() {
624  assert(!IncludeMacroStack.empty() && "Ran out of stack entries to load");
625
626  if (CurTokenLexer) {
627    // Delete or cache the now-dead macro expander.
628    if (NumCachedTokenLexers == TokenLexerCacheSize)
629      CurTokenLexer.reset();
630    else
631      TokenLexerCache[NumCachedTokenLexers++] = std::move(CurTokenLexer);
632  }
633
634  PopIncludeMacroStack();
635}
636
637/// HandleMicrosoftCommentPaste - When the macro expander pastes together a
638/// comment (/##/) in microsoft mode, this method handles updating the current
639/// state, returning the token on the next source line.
640void Preprocessor::HandleMicrosoftCommentPaste(Token &Tok) {
641  assert(CurTokenLexer && !CurPPLexer &&
642         "Pasted comment can only be formed from macro");
643  // We handle this by scanning for the closest real lexer, switching it to
644  // raw mode and preprocessor mode.  This will cause it to return \n as an
645  // explicit EOD token.
646  PreprocessorLexer *FoundLexer = nullptr;
647  bool LexerWasInPPMode = false;
648  for (const IncludeStackInfo &ISI : llvm::reverse(IncludeMacroStack)) {
649    if (ISI.ThePPLexer == nullptr) continue;  // Scan for a real lexer.
650
651    // Once we find a real lexer, mark it as raw mode (disabling macro
652    // expansions) and preprocessor mode (return EOD).  We know that the lexer
653    // was *not* in raw mode before, because the macro that the comment came
654    // from was expanded.  However, it could have already been in preprocessor
655    // mode (#if COMMENT) in which case we have to return it to that mode and
656    // return EOD.
657    FoundLexer = ISI.ThePPLexer;
658    FoundLexer->LexingRawMode = true;
659    LexerWasInPPMode = FoundLexer->ParsingPreprocessorDirective;
660    FoundLexer->ParsingPreprocessorDirective = true;
661    break;
662  }
663
664  // Okay, we either found and switched over the lexer, or we didn't find a
665  // lexer.  In either case, finish off the macro the comment came from, getting
666  // the next token.
667  if (!HandleEndOfTokenLexer(Tok)) Lex(Tok);
668
669  // Discarding comments as long as we don't have EOF or EOD.  This 'comments
670  // out' the rest of the line, including any tokens that came from other macros
671  // that were active, as in:
672  //  #define submacro a COMMENT b
673  //    submacro c
674  // which should lex to 'a' only: 'b' and 'c' should be removed.
675  while (Tok.isNot(tok::eod) && Tok.isNot(tok::eof))
676    Lex(Tok);
677
678  // If we got an eod token, then we successfully found the end of the line.
679  if (Tok.is(tok::eod)) {
680    assert(FoundLexer && "Can't get end of line without an active lexer");
681    // Restore the lexer back to normal mode instead of raw mode.
682    FoundLexer->LexingRawMode = false;
683
684    // If the lexer was already in preprocessor mode, just return the EOD token
685    // to finish the preprocessor line.
686    if (LexerWasInPPMode) return;
687
688    // Otherwise, switch out of PP mode and return the next lexed token.
689    FoundLexer->ParsingPreprocessorDirective = false;
690    return Lex(Tok);
691  }
692
693  // If we got an EOF token, then we reached the end of the token stream but
694  // didn't find an explicit \n.  This can only happen if there was no lexer
695  // active (an active lexer would return EOD at EOF if there was no \n in
696  // preprocessor directive mode), so just return EOF as our token.
697  assert(!FoundLexer && "Lexer should return EOD before EOF in PP mode");
698}
699
700void Preprocessor::EnterSubmodule(Module *M, SourceLocation ImportLoc,
701                                  bool ForPragma) {
702  if (!getLangOpts().ModulesLocalVisibility) {
703    // Just track that we entered this submodule.
704    BuildingSubmoduleStack.push_back(
705        BuildingSubmoduleInfo(M, ImportLoc, ForPragma, CurSubmoduleState,
706                              PendingModuleMacroNames.size()));
707    if (Callbacks)
708      Callbacks->EnteredSubmodule(M, ImportLoc, ForPragma);
709    return;
710  }
711
712  // Resolve as much of the module definition as we can now, before we enter
713  // one of its headers.
714  // FIXME: Can we enable Complain here?
715  // FIXME: Can we do this when local visibility is disabled?
716  ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
717  ModMap.resolveExports(M, /*Complain=*/false);
718  ModMap.resolveUses(M, /*Complain=*/false);
719  ModMap.resolveConflicts(M, /*Complain=*/false);
720
721  // If this is the first time we've entered this module, set up its state.
722  auto R = Submodules.insert(std::make_pair(M, SubmoduleState()));
723  auto &State = R.first->second;
724  bool FirstTime = R.second;
725  if (FirstTime) {
726    // Determine the set of starting macros for this submodule; take these
727    // from the "null" module (the predefines buffer).
728    //
729    // FIXME: If we have local visibility but not modules enabled, the
730    // NullSubmoduleState is polluted by #defines in the top-level source
731    // file.
732    auto &StartingMacros = NullSubmoduleState.Macros;
733
734    // Restore to the starting state.
735    // FIXME: Do this lazily, when each macro name is first referenced.
736    for (auto &Macro : StartingMacros) {
737      // Skip uninteresting macros.
738      if (!Macro.second.getLatest() &&
739          Macro.second.getOverriddenMacros().empty())
740        continue;
741
742      MacroState MS(Macro.second.getLatest());
743      MS.setOverriddenMacros(*this, Macro.second.getOverriddenMacros());
744      State.Macros.insert(std::make_pair(Macro.first, std::move(MS)));
745    }
746  }
747
748  // Track that we entered this module.
749  BuildingSubmoduleStack.push_back(
750      BuildingSubmoduleInfo(M, ImportLoc, ForPragma, CurSubmoduleState,
751                            PendingModuleMacroNames.size()));
752
753  if (Callbacks)
754    Callbacks->EnteredSubmodule(M, ImportLoc, ForPragma);
755
756  // Switch to this submodule as the current submodule.
757  CurSubmoduleState = &State;
758
759  // This module is visible to itself.
760  if (FirstTime)
761    makeModuleVisible(M, ImportLoc);
762}
763
764bool Preprocessor::needModuleMacros() const {
765  // If we're not within a submodule, we never need to create ModuleMacros.
766  if (BuildingSubmoduleStack.empty())
767    return false;
768  // If we are tracking module macro visibility even for textually-included
769  // headers, we need ModuleMacros.
770  if (getLangOpts().ModulesLocalVisibility)
771    return true;
772  // Otherwise, we only need module macros if we're actually compiling a module
773  // interface.
774  return getLangOpts().isCompilingModule();
775}
776
777Module *Preprocessor::LeaveSubmodule(bool ForPragma) {
778  if (BuildingSubmoduleStack.empty() ||
779      BuildingSubmoduleStack.back().IsPragma != ForPragma) {
780    assert(ForPragma && "non-pragma module enter/leave mismatch");
781    return nullptr;
782  }
783
784  auto &Info = BuildingSubmoduleStack.back();
785
786  Module *LeavingMod = Info.M;
787  SourceLocation ImportLoc = Info.ImportLoc;
788
789  if (!needModuleMacros() ||
790      (!getLangOpts().ModulesLocalVisibility &&
791       LeavingMod->getTopLevelModuleName() != getLangOpts().CurrentModule)) {
792    // If we don't need module macros, or this is not a module for which we
793    // are tracking macro visibility, don't build any, and preserve the list
794    // of pending names for the surrounding submodule.
795    BuildingSubmoduleStack.pop_back();
796
797    if (Callbacks)
798      Callbacks->LeftSubmodule(LeavingMod, ImportLoc, ForPragma);
799
800    makeModuleVisible(LeavingMod, ImportLoc);
801    return LeavingMod;
802  }
803
804  // Create ModuleMacros for any macros defined in this submodule.
805  llvm::SmallPtrSet<const IdentifierInfo*, 8> VisitedMacros;
806  for (unsigned I = Info.OuterPendingModuleMacroNames;
807       I != PendingModuleMacroNames.size(); ++I) {
808    auto *II = const_cast<IdentifierInfo*>(PendingModuleMacroNames[I]);
809    if (!VisitedMacros.insert(II).second)
810      continue;
811
812    auto MacroIt = CurSubmoduleState->Macros.find(II);
813    if (MacroIt == CurSubmoduleState->Macros.end())
814      continue;
815    auto &Macro = MacroIt->second;
816
817    // Find the starting point for the MacroDirective chain in this submodule.
818    MacroDirective *OldMD = nullptr;
819    auto *OldState = Info.OuterSubmoduleState;
820    if (getLangOpts().ModulesLocalVisibility)
821      OldState = &NullSubmoduleState;
822    if (OldState && OldState != CurSubmoduleState) {
823      // FIXME: It'd be better to start at the state from when we most recently
824      // entered this submodule, but it doesn't really matter.
825      auto &OldMacros = OldState->Macros;
826      auto OldMacroIt = OldMacros.find(II);
827      if (OldMacroIt == OldMacros.end())
828        OldMD = nullptr;
829      else
830        OldMD = OldMacroIt->second.getLatest();
831    }
832
833    // This module may have exported a new macro. If so, create a ModuleMacro
834    // representing that fact.
835    bool ExplicitlyPublic = false;
836    for (auto *MD = Macro.getLatest(); MD != OldMD; MD = MD->getPrevious()) {
837      assert(MD && "broken macro directive chain");
838
839      if (auto *VisMD = dyn_cast<VisibilityMacroDirective>(MD)) {
840        // The latest visibility directive for a name in a submodule affects
841        // all the directives that come before it.
842        if (VisMD->isPublic())
843          ExplicitlyPublic = true;
844        else if (!ExplicitlyPublic)
845          // Private with no following public directive: not exported.
846          break;
847      } else {
848        MacroInfo *Def = nullptr;
849        if (DefMacroDirective *DefMD = dyn_cast<DefMacroDirective>(MD))
850          Def = DefMD->getInfo();
851
852        // FIXME: Issue a warning if multiple headers for the same submodule
853        // define a macro, rather than silently ignoring all but the first.
854        bool IsNew;
855        // Don't bother creating a module macro if it would represent a #undef
856        // that doesn't override anything.
857        if (Def || !Macro.getOverriddenMacros().empty())
858          addModuleMacro(LeavingMod, II, Def,
859                         Macro.getOverriddenMacros(), IsNew);
860
861        if (!getLangOpts().ModulesLocalVisibility) {
862          // This macro is exposed to the rest of this compilation as a
863          // ModuleMacro; we don't need to track its MacroDirective any more.
864          Macro.setLatest(nullptr);
865          Macro.setOverriddenMacros(*this, {});
866        }
867        break;
868      }
869    }
870  }
871  PendingModuleMacroNames.resize(Info.OuterPendingModuleMacroNames);
872
873  // FIXME: Before we leave this submodule, we should parse all the other
874  // headers within it. Otherwise, we're left with an inconsistent state
875  // where we've made the module visible but don't yet have its complete
876  // contents.
877
878  // Put back the outer module's state, if we're tracking it.
879  if (getLangOpts().ModulesLocalVisibility)
880    CurSubmoduleState = Info.OuterSubmoduleState;
881
882  BuildingSubmoduleStack.pop_back();
883
884  if (Callbacks)
885    Callbacks->LeftSubmodule(LeavingMod, ImportLoc, ForPragma);
886
887  // A nested #include makes the included submodule visible.
888  makeModuleVisible(LeavingMod, ImportLoc);
889  return LeavingMod;
890}
891