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 Range: llvm::drop_begin(RangeOrContainer: IncludeMacroStack),
44 P: [&](const IncludeStackInfo &ISI) -> bool { return IsFileLexer(I: 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(C: IncludeMacroStack)) {
56 if (IsFileLexer(I: 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(Loc: FileStart)) << "";
85 return true;
86 }
87
88 if (isCodeCompletionEnabled() &&
89 SourceMgr.getFileEntryForID(FID) == CodeCompletionFile) {
90 CodeCompletionFileLoc = SourceMgr.getLocForStartOfFile(FID);
91 CodeCompletionLoc =
92 CodeCompletionFileLoc.getLocWithOffset(Offset: 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, Dir: 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(p: 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(Loc: CurLexer->getFileLoc());
134
135 FileID PrevFID;
136 SourceLocation EnterLoc;
137 if (PrevPPLexer) {
138 PrevFID = PrevPPLexer->getFileID();
139 EnterLoc = PrevPPLexer->getSourceLocation();
140 }
141 Callbacks->FileChanged(Loc: CurLexer->getFileLoc(), Reason: PPCallbacks::EnterFile,
142 FileType, PrevFID);
143 Callbacks->LexedFileChanged(FID: CurLexer->getFileID(),
144 Reason: PPCallbacks::LexedFileChangeReason::EnterFile,
145 FileType, PrevFID, Loc: 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>(args&: Tok, args&: ILEnd, args&: Macro, args&: Args, args&: *this);
156 } else {
157 TokLexer = std::move(TokenLexerCache[--NumCachedTokenLexers]);
158 TokLexer->Init(Tok, ELEnd: ILEnd, MI: Macro, Actuals: 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(I: CachedTokens.begin() + CachedLexPos,
189 From: Toks, To: 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 args&: Toks, args&: NumToks, args&: DisableMacroExpansion, args&: OwnsTokens, args&: IsReinject, args&: *this);
209 } else {
210 TokLexer = std::move(TokenLexerCache[--NumCachedTokenLexers]);
211 TokLexer->Init(TokArray: 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(DirName: Path)) {
233 if (*CurDir == Dir) {
234 Result = FilePath.substr(Start: Path.size());
235 llvm::sys::path::append(path&: Result,
236 a: llvm::sys::path::filename(path: File.getName()));
237 return;
238 }
239 }
240
241 Path = llvm::sys::path::parent_path(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(Elt: &Mod);
286 for (auto *M : Mod.submodules())
287 collectAllSubModulesWithUmbrellaHeader(Mod: *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(SourceFile: UmbrellaHeader->Entry);
295 SourceLocation ExpectedHeadersLoc = SourceMgr.getLocForEndOfFile(FID: File);
296 if (getDiagnostics().isIgnored(diag::DiagID: warn_uncovered_module_header,
297 Loc: 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(path: Entry->path()))
312 .Cases(S0: ".h", S1: ".H", S2: ".hh", S3: ".hpp", Value: true)
313 .Default(Value: false))
314 continue;
315
316 if (auto Header = getFileManager().getOptionalFileRef(Filename: Entry->path()))
317 if (!getSourceManager().hasFileInfo(File: *Header)) {
318 if (!ModMap.isHeaderInUnavailableModule(Header: *Header)) {
319 // Find the relative path that would access this header.
320 SmallString<128> RelativePath;
321 computeRelativePath(FM&: FileMgr, Dir: *Dir, File: *Header, Result&: 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(StartLoc&: 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, TokEnd: EndPos, Kind: 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(File: *FE, ControllingMacro);
371 if (MacroInfo *MI = getMacroInfo(II: ControllingMacro))
372 MI->setUsedForHeaderGuard(true);
373 if (const IdentifierInfo *DefinedMacro =
374 CurPPLexer->MIOpt.GetDefinedMacro()) {
375 if (!isMacroDefined(II: ControllingMacro) &&
376 DefinedMacro != ControllingMacro &&
377 CurLexer->isFirstTimeLexingFile()) {
378
379 // If the edit distance between the two macros is more than 50%,
380 // DefinedMacro may not be header guard, or can be header guard of
381 // another header file. Therefore, it maybe defining something
382 // completely different. This can be observed in the wild when
383 // handling feature macros or header guards in different files.
384
385 const StringRef ControllingMacroName = ControllingMacro->getName();
386 const StringRef DefinedMacroName = DefinedMacro->getName();
387 const size_t MaxHalfLength = std::max(a: ControllingMacroName.size(),
388 b: DefinedMacroName.size()) / 2;
389 const unsigned ED = ControllingMacroName.edit_distance(
390 Other: DefinedMacroName, AllowReplacements: true, MaxEditDistance: MaxHalfLength);
391 if (ED <= MaxHalfLength) {
392 // Emit a warning for a bad header guard.
393 Diag(CurPPLexer->MIOpt.GetMacroLocation(),
394 diag::warn_header_guard)
395 << CurPPLexer->MIOpt.GetMacroLocation() << ControllingMacro;
396 Diag(CurPPLexer->MIOpt.GetDefinedLocation(),
397 diag::note_header_guard)
398 << CurPPLexer->MIOpt.GetDefinedLocation() << DefinedMacro
399 << ControllingMacro
400 << FixItHint::CreateReplacement(
401 RemoveRange: CurPPLexer->MIOpt.GetDefinedLocation(),
402 Code: ControllingMacro->getName());
403 }
404 }
405 }
406 }
407 }
408 }
409
410 // Complain about reaching a true EOF within arc_cf_code_audited.
411 // We don't want to complain about reaching the end of a macro
412 // instantiation or a _Pragma.
413 if (PragmaARCCFCodeAuditedInfo.second.isValid() && !isEndOfMacro &&
414 !(CurLexer && CurLexer->Is_PragmaLexer)) {
415 Diag(PragmaARCCFCodeAuditedInfo.second,
416 diag::err_pp_eof_in_arc_cf_code_audited);
417
418 // Recover by leaving immediately.
419 PragmaARCCFCodeAuditedInfo = {nullptr, SourceLocation()};
420 }
421
422 // Complain about reaching a true EOF within assume_nonnull.
423 // We don't want to complain about reaching the end of a macro
424 // instantiation or a _Pragma.
425 if (PragmaAssumeNonNullLoc.isValid() &&
426 !isEndOfMacro && !(CurLexer && CurLexer->Is_PragmaLexer)) {
427 // If we're at the end of generating a preamble, we should record the
428 // unterminated \#pragma clang assume_nonnull so we can restore it later
429 // when the preamble is loaded into the main file.
430 if (isRecordingPreamble() && isInPrimaryFile())
431 PreambleRecordedPragmaAssumeNonNullLoc = PragmaAssumeNonNullLoc;
432 else
433 Diag(PragmaAssumeNonNullLoc, diag::err_pp_eof_in_assume_nonnull);
434 // Recover by leaving immediately.
435 PragmaAssumeNonNullLoc = SourceLocation();
436 }
437
438 bool LeavingPCHThroughHeader = false;
439
440 // If this is a #include'd file, pop it off the include stack and continue
441 // lexing the #includer file.
442 if (!IncludeMacroStack.empty()) {
443
444 // If we lexed the code-completion file, act as if we reached EOF.
445 if (isCodeCompletionEnabled() && CurPPLexer &&
446 SourceMgr.getLocForStartOfFile(FID: CurPPLexer->getFileID()) ==
447 CodeCompletionFileLoc) {
448 assert(CurLexer && "Got EOF but no current lexer set!");
449 Result.startToken();
450 CurLexer->FormTokenWithChars(Result, TokEnd: CurLexer->BufferEnd, Kind: tok::eof);
451 CurLexer.reset();
452
453 CurPPLexer = nullptr;
454 recomputeCurLexerKind();
455 return true;
456 }
457
458 if (!isEndOfMacro && CurPPLexer &&
459 (SourceMgr.getIncludeLoc(FID: CurPPLexer->getFileID()).isValid() ||
460 // Predefines file doesn't have a valid include location.
461 (PredefinesFileID.isValid() &&
462 CurPPLexer->getFileID() == PredefinesFileID))) {
463 // Notify SourceManager to record the number of FileIDs that were created
464 // during lexing of the #include'd file.
465 unsigned NumFIDs =
466 SourceMgr.local_sloc_entry_size() -
467 CurPPLexer->getInitialNumSLocEntries() + 1/*#include'd file*/;
468 SourceMgr.setNumCreatedFIDsForFileID(FID: CurPPLexer->getFileID(), NumFIDs);
469 }
470
471 bool ExitedFromPredefinesFile = false;
472 FileID ExitedFID;
473 if (!isEndOfMacro && CurPPLexer) {
474 ExitedFID = CurPPLexer->getFileID();
475
476 assert(PredefinesFileID.isValid() &&
477 "HandleEndOfFile is called before PredefinesFileId is set");
478 ExitedFromPredefinesFile = (PredefinesFileID == ExitedFID);
479 }
480
481 if (LeavingSubmodule) {
482 // We're done with this submodule.
483 Module *M = LeaveSubmodule(/*ForPragma*/false);
484
485 // Notify the parser that we've left the module.
486 const char *EndPos = getCurLexerEndPos();
487 Result.startToken();
488 CurLexer->BufferPtr = EndPos;
489 CurLexer->FormTokenWithChars(Result, TokEnd: EndPos, Kind: tok::annot_module_end);
490 Result.setAnnotationEndLoc(Result.getLocation());
491 Result.setAnnotationValue(M);
492 }
493
494 bool FoundPCHThroughHeader = false;
495 if (CurPPLexer && creatingPCHWithThroughHeader() &&
496 isPCHThroughHeader(
497 FE: SourceMgr.getFileEntryForID(FID: CurPPLexer->getFileID())))
498 FoundPCHThroughHeader = true;
499
500 // We're done with the #included file.
501 RemoveTopOfLexerStack();
502
503 // Propagate info about start-of-line/leading white-space/etc.
504 PropagateLineStartLeadingSpaceInfo(Result);
505
506 // Notify the client, if desired, that we are in a new source file.
507 if (Callbacks && !isEndOfMacro && CurPPLexer) {
508 SourceLocation Loc = CurPPLexer->getSourceLocation();
509 SrcMgr::CharacteristicKind FileType =
510 SourceMgr.getFileCharacteristic(Loc);
511 Callbacks->FileChanged(Loc, Reason: PPCallbacks::ExitFile, FileType, PrevFID: ExitedFID);
512 Callbacks->LexedFileChanged(FID: CurPPLexer->getFileID(),
513 Reason: PPCallbacks::LexedFileChangeReason::ExitFile,
514 FileType, PrevFID: ExitedFID, Loc);
515 }
516
517 // Restore conditional stack as well as the recorded
518 // \#pragma clang assume_nonnull from the preamble right after exiting
519 // from the predefines file.
520 if (ExitedFromPredefinesFile) {
521 replayPreambleConditionalStack();
522 if (PreambleRecordedPragmaAssumeNonNullLoc.isValid())
523 PragmaAssumeNonNullLoc = PreambleRecordedPragmaAssumeNonNullLoc;
524 }
525
526 if (!isEndOfMacro && CurPPLexer && FoundPCHThroughHeader &&
527 (isInPrimaryFile() ||
528 CurPPLexer->getFileID() == getPredefinesFileID())) {
529 // Leaving the through header. Continue directly to end of main file
530 // processing.
531 LeavingPCHThroughHeader = true;
532 } else {
533 // Client should lex another token unless we generated an EOM.
534 return LeavingSubmodule;
535 }
536 }
537 // If this is the end of the main file, form an EOF token.
538 assert(CurLexer && "Got EOF but no current lexer set!");
539 const char *EndPos = getCurLexerEndPos();
540 Result.startToken();
541 CurLexer->BufferPtr = EndPos;
542
543 if (getLangOpts().IncrementalExtensions) {
544 CurLexer->FormTokenWithChars(Result, TokEnd: EndPos, Kind: tok::annot_repl_input_end);
545 Result.setAnnotationEndLoc(Result.getLocation());
546 Result.setAnnotationValue(nullptr);
547 } else {
548 CurLexer->FormTokenWithChars(Result, TokEnd: EndPos, Kind: tok::eof);
549 }
550
551 if (isCodeCompletionEnabled()) {
552 // Inserting the code-completion point increases the source buffer by 1,
553 // but the main FileID was created before inserting the point.
554 // Compensate by reducing the EOF location by 1, otherwise the location
555 // will point to the next FileID.
556 // FIXME: This is hacky, the code-completion point should probably be
557 // inserted before the main FileID is created.
558 if (CurLexer->getFileLoc() == CodeCompletionFileLoc)
559 Result.setLocation(Result.getLocation().getLocWithOffset(Offset: -1));
560 }
561
562 if (creatingPCHWithThroughHeader() && !LeavingPCHThroughHeader) {
563 // Reached the end of the compilation without finding the through header.
564 Diag(CurLexer->getFileLoc(), diag::err_pp_through_header_not_seen)
565 << PPOpts->PCHThroughHeader << 0;
566 }
567
568 if (!isIncrementalProcessingEnabled())
569 // We're done with lexing.
570 CurLexer.reset();
571
572 if (!isIncrementalProcessingEnabled())
573 CurPPLexer = nullptr;
574
575 if (TUKind == TU_Complete) {
576 // This is the end of the top-level file. 'WarnUnusedMacroLocs' has
577 // collected all macro locations that we need to warn because they are not
578 // used.
579 for (WarnUnusedMacroLocsTy::iterator
580 I=WarnUnusedMacroLocs.begin(), E=WarnUnusedMacroLocs.end();
581 I!=E; ++I)
582 Diag(*I, diag::pp_macro_not_used);
583 }
584
585 // If we are building a module that has an umbrella header, make sure that
586 // each of the headers within the directory, including all submodules, is
587 // covered by the umbrella header was actually included by the umbrella
588 // header.
589 if (Module *Mod = getCurrentModule()) {
590 llvm::SmallVector<const Module *, 4> AllMods;
591 collectAllSubModulesWithUmbrellaHeader(Mod: *Mod, SubMods&: AllMods);
592 for (auto *M : AllMods)
593 diagnoseMissingHeaderInUmbrellaDir(Mod: *M);
594 }
595
596 return true;
597}
598
599/// HandleEndOfTokenLexer - This callback is invoked when the current TokenLexer
600/// hits the end of its token stream.
601bool Preprocessor::HandleEndOfTokenLexer(Token &Result) {
602 assert(CurTokenLexer && !CurPPLexer &&
603 "Ending a macro when currently in a #include file!");
604
605 if (!MacroExpandingLexersStack.empty() &&
606 MacroExpandingLexersStack.back().first == CurTokenLexer.get())
607 removeCachedMacroExpandedTokensOfLastLexer();
608
609 // Delete or cache the now-dead macro expander.
610 if (NumCachedTokenLexers == TokenLexerCacheSize)
611 CurTokenLexer.reset();
612 else
613 TokenLexerCache[NumCachedTokenLexers++] = std::move(CurTokenLexer);
614
615 // Handle this like a #include file being popped off the stack.
616 return HandleEndOfFile(Result, isEndOfMacro: true);
617}
618
619/// RemoveTopOfLexerStack - Pop the current lexer/macro exp off the top of the
620/// lexer stack. This should only be used in situations where the current
621/// state of the top-of-stack lexer is unknown.
622void Preprocessor::RemoveTopOfLexerStack() {
623 assert(!IncludeMacroStack.empty() && "Ran out of stack entries to load");
624
625 if (CurTokenLexer) {
626 // Delete or cache the now-dead macro expander.
627 if (NumCachedTokenLexers == TokenLexerCacheSize)
628 CurTokenLexer.reset();
629 else
630 TokenLexerCache[NumCachedTokenLexers++] = std::move(CurTokenLexer);
631 }
632
633 PopIncludeMacroStack();
634}
635
636/// HandleMicrosoftCommentPaste - When the macro expander pastes together a
637/// comment (/##/) in microsoft mode, this method handles updating the current
638/// state, returning the token on the next source line.
639void Preprocessor::HandleMicrosoftCommentPaste(Token &Tok) {
640 assert(CurTokenLexer && !CurPPLexer &&
641 "Pasted comment can only be formed from macro");
642 // We handle this by scanning for the closest real lexer, switching it to
643 // raw mode and preprocessor mode. This will cause it to return \n as an
644 // explicit EOD token.
645 PreprocessorLexer *FoundLexer = nullptr;
646 bool LexerWasInPPMode = false;
647 for (const IncludeStackInfo &ISI : llvm::reverse(C&: IncludeMacroStack)) {
648 if (ISI.ThePPLexer == nullptr) continue; // Scan for a real lexer.
649
650 // Once we find a real lexer, mark it as raw mode (disabling macro
651 // expansions) and preprocessor mode (return EOD). We know that the lexer
652 // was *not* in raw mode before, because the macro that the comment came
653 // from was expanded. However, it could have already been in preprocessor
654 // mode (#if COMMENT) in which case we have to return it to that mode and
655 // return EOD.
656 FoundLexer = ISI.ThePPLexer;
657 FoundLexer->LexingRawMode = true;
658 LexerWasInPPMode = FoundLexer->ParsingPreprocessorDirective;
659 FoundLexer->ParsingPreprocessorDirective = true;
660 break;
661 }
662
663 // Okay, we either found and switched over the lexer, or we didn't find a
664 // lexer. In either case, finish off the macro the comment came from, getting
665 // the next token.
666 if (!HandleEndOfTokenLexer(Result&: Tok)) Lex(Result&: Tok);
667
668 // Discarding comments as long as we don't have EOF or EOD. This 'comments
669 // out' the rest of the line, including any tokens that came from other macros
670 // that were active, as in:
671 // #define submacro a COMMENT b
672 // submacro c
673 // which should lex to 'a' only: 'b' and 'c' should be removed.
674 while (Tok.isNot(K: tok::eod) && Tok.isNot(K: tok::eof))
675 Lex(Result&: Tok);
676
677 // If we got an eod token, then we successfully found the end of the line.
678 if (Tok.is(K: tok::eod)) {
679 assert(FoundLexer && "Can't get end of line without an active lexer");
680 // Restore the lexer back to normal mode instead of raw mode.
681 FoundLexer->LexingRawMode = false;
682
683 // If the lexer was already in preprocessor mode, just return the EOD token
684 // to finish the preprocessor line.
685 if (LexerWasInPPMode) return;
686
687 // Otherwise, switch out of PP mode and return the next lexed token.
688 FoundLexer->ParsingPreprocessorDirective = false;
689 return Lex(Result&: Tok);
690 }
691
692 // If we got an EOF token, then we reached the end of the token stream but
693 // didn't find an explicit \n. This can only happen if there was no lexer
694 // active (an active lexer would return EOD at EOF if there was no \n in
695 // preprocessor directive mode), so just return EOF as our token.
696 assert(!FoundLexer && "Lexer should return EOD before EOF in PP mode");
697}
698
699void Preprocessor::EnterSubmodule(Module *M, SourceLocation ImportLoc,
700 bool ForPragma) {
701 if (!getLangOpts().ModulesLocalVisibility) {
702 // Just track that we entered this submodule.
703 BuildingSubmoduleStack.push_back(
704 Elt: BuildingSubmoduleInfo(M, ImportLoc, ForPragma, CurSubmoduleState,
705 PendingModuleMacroNames.size()));
706 if (Callbacks)
707 Callbacks->EnteredSubmodule(M, ImportLoc, ForPragma);
708 return;
709 }
710
711 // Resolve as much of the module definition as we can now, before we enter
712 // one of its headers.
713 // FIXME: Can we enable Complain here?
714 // FIXME: Can we do this when local visibility is disabled?
715 ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
716 ModMap.resolveExports(Mod: M, /*Complain=*/false);
717 ModMap.resolveUses(Mod: M, /*Complain=*/false);
718 ModMap.resolveConflicts(Mod: M, /*Complain=*/false);
719
720 // If this is the first time we've entered this module, set up its state.
721 auto R = Submodules.insert(x: std::make_pair(x&: M, y: SubmoduleState()));
722 auto &State = R.first->second;
723 bool FirstTime = R.second;
724 if (FirstTime) {
725 // Determine the set of starting macros for this submodule; take these
726 // from the "null" module (the predefines buffer).
727 //
728 // FIXME: If we have local visibility but not modules enabled, the
729 // NullSubmoduleState is polluted by #defines in the top-level source
730 // file.
731 auto &StartingMacros = NullSubmoduleState.Macros;
732
733 // Restore to the starting state.
734 // FIXME: Do this lazily, when each macro name is first referenced.
735 for (auto &Macro : StartingMacros) {
736 // Skip uninteresting macros.
737 if (!Macro.second.getLatest() &&
738 Macro.second.getOverriddenMacros().empty())
739 continue;
740
741 MacroState MS(Macro.second.getLatest());
742 MS.setOverriddenMacros(PP&: *this, Overrides: Macro.second.getOverriddenMacros());
743 State.Macros.insert(KV: std::make_pair(x&: Macro.first, y: std::move(MS)));
744 }
745 }
746
747 // Track that we entered this module.
748 BuildingSubmoduleStack.push_back(
749 Elt: BuildingSubmoduleInfo(M, ImportLoc, ForPragma, CurSubmoduleState,
750 PendingModuleMacroNames.size()));
751
752 if (Callbacks)
753 Callbacks->EnteredSubmodule(M, ImportLoc, ForPragma);
754
755 // Switch to this submodule as the current submodule.
756 CurSubmoduleState = &State;
757
758 // This module is visible to itself.
759 if (FirstTime)
760 makeModuleVisible(M, Loc: ImportLoc);
761}
762
763bool Preprocessor::needModuleMacros() const {
764 // If we're not within a submodule, we never need to create ModuleMacros.
765 if (BuildingSubmoduleStack.empty())
766 return false;
767 // If we are tracking module macro visibility even for textually-included
768 // headers, we need ModuleMacros.
769 if (getLangOpts().ModulesLocalVisibility)
770 return true;
771 // Otherwise, we only need module macros if we're actually compiling a module
772 // interface.
773 return getLangOpts().isCompilingModule();
774}
775
776Module *Preprocessor::LeaveSubmodule(bool ForPragma) {
777 if (BuildingSubmoduleStack.empty() ||
778 BuildingSubmoduleStack.back().IsPragma != ForPragma) {
779 assert(ForPragma && "non-pragma module enter/leave mismatch");
780 return nullptr;
781 }
782
783 auto &Info = BuildingSubmoduleStack.back();
784
785 Module *LeavingMod = Info.M;
786 SourceLocation ImportLoc = Info.ImportLoc;
787
788 if (!needModuleMacros() ||
789 (!getLangOpts().ModulesLocalVisibility &&
790 LeavingMod->getTopLevelModuleName() != getLangOpts().CurrentModule)) {
791 // If we don't need module macros, or this is not a module for which we
792 // are tracking macro visibility, don't build any, and preserve the list
793 // of pending names for the surrounding submodule.
794 BuildingSubmoduleStack.pop_back();
795
796 if (Callbacks)
797 Callbacks->LeftSubmodule(M: LeavingMod, ImportLoc, ForPragma);
798
799 makeModuleVisible(M: LeavingMod, Loc: ImportLoc);
800 return LeavingMod;
801 }
802
803 // Create ModuleMacros for any macros defined in this submodule.
804 llvm::SmallPtrSet<const IdentifierInfo*, 8> VisitedMacros;
805 for (unsigned I = Info.OuterPendingModuleMacroNames;
806 I != PendingModuleMacroNames.size(); ++I) {
807 const auto *II = PendingModuleMacroNames[I];
808 if (!VisitedMacros.insert(Ptr: II).second)
809 continue;
810
811 auto MacroIt = CurSubmoduleState->Macros.find(Val: II);
812 if (MacroIt == CurSubmoduleState->Macros.end())
813 continue;
814 auto &Macro = MacroIt->second;
815
816 // Find the starting point for the MacroDirective chain in this submodule.
817 MacroDirective *OldMD = nullptr;
818 auto *OldState = Info.OuterSubmoduleState;
819 if (getLangOpts().ModulesLocalVisibility)
820 OldState = &NullSubmoduleState;
821 if (OldState && OldState != CurSubmoduleState) {
822 // FIXME: It'd be better to start at the state from when we most recently
823 // entered this submodule, but it doesn't really matter.
824 auto &OldMacros = OldState->Macros;
825 auto OldMacroIt = OldMacros.find(Val: II);
826 if (OldMacroIt == OldMacros.end())
827 OldMD = nullptr;
828 else
829 OldMD = OldMacroIt->second.getLatest();
830 }
831
832 // This module may have exported a new macro. If so, create a ModuleMacro
833 // representing that fact.
834 bool ExplicitlyPublic = false;
835 for (auto *MD = Macro.getLatest(); MD != OldMD; MD = MD->getPrevious()) {
836 assert(MD && "broken macro directive chain");
837
838 if (auto *VisMD = dyn_cast<VisibilityMacroDirective>(Val: MD)) {
839 // The latest visibility directive for a name in a submodule affects
840 // all the directives that come before it.
841 if (VisMD->isPublic())
842 ExplicitlyPublic = true;
843 else if (!ExplicitlyPublic)
844 // Private with no following public directive: not exported.
845 break;
846 } else {
847 MacroInfo *Def = nullptr;
848 if (DefMacroDirective *DefMD = dyn_cast<DefMacroDirective>(Val: MD))
849 Def = DefMD->getInfo();
850
851 // FIXME: Issue a warning if multiple headers for the same submodule
852 // define a macro, rather than silently ignoring all but the first.
853 bool IsNew;
854 // Don't bother creating a module macro if it would represent a #undef
855 // that doesn't override anything.
856 if (Def || !Macro.getOverriddenMacros().empty())
857 addModuleMacro(Mod: LeavingMod, II, Macro: Def, Overrides: Macro.getOverriddenMacros(),
858 IsNew);
859
860 if (!getLangOpts().ModulesLocalVisibility) {
861 // This macro is exposed to the rest of this compilation as a
862 // ModuleMacro; we don't need to track its MacroDirective any more.
863 Macro.setLatest(nullptr);
864 Macro.setOverriddenMacros(PP&: *this, Overrides: {});
865 }
866 break;
867 }
868 }
869 }
870 PendingModuleMacroNames.resize(N: Info.OuterPendingModuleMacroNames);
871
872 // FIXME: Before we leave this submodule, we should parse all the other
873 // headers within it. Otherwise, we're left with an inconsistent state
874 // where we've made the module visible but don't yet have its complete
875 // contents.
876
877 // Put back the outer module's state, if we're tracking it.
878 if (getLangOpts().ModulesLocalVisibility)
879 CurSubmoduleState = Info.OuterSubmoduleState;
880
881 BuildingSubmoduleStack.pop_back();
882
883 if (Callbacks)
884 Callbacks->LeftSubmodule(M: LeavingMod, ImportLoc, ForPragma);
885
886 // A nested #include makes the included submodule visible.
887 makeModuleVisible(M: LeavingMod, Loc: ImportLoc);
888 return LeavingMod;
889}
890

source code of clang/lib/Lex/PPLexerChange.cpp