clang  14.0.0git
Lexer.h
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1 //===- Lexer.h - C Language Family Lexer ------------------------*- 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 // This file defines the Lexer interface.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_LEX_LEXER_H
14 #define LLVM_CLANG_LEX_LEXER_H
15 
18 #include "clang/Basic/TokenKinds.h"
20 #include "clang/Lex/Token.h"
21 #include "llvm/ADT/Optional.h"
22 #include "llvm/ADT/SmallVector.h"
23 #include "llvm/ADT/StringRef.h"
24 #include <cassert>
25 #include <cstdint>
26 #include <string>
27 
28 namespace llvm {
29 
30 class MemoryBufferRef;
31 
32 } // namespace llvm
33 
34 namespace clang {
35 
36 class DiagnosticBuilder;
37 class Preprocessor;
38 class SourceManager;
39 
40 /// ConflictMarkerKind - Kinds of conflict marker which the lexer might be
41 /// recovering from.
43  /// Not within a conflict marker.
45 
46  /// A normal or diff3 conflict marker, initiated by at least 7 "<"s,
47  /// separated by at least 7 "="s or "|"s, and terminated by at least 7 ">"s.
49 
50  /// A Perforce-style conflict marker, initiated by 4 ">"s,
51  /// separated by 4 "="s, and terminated by 4 "<"s.
53 };
54 
55 /// Describes the bounds (start, size) of the preamble and a flag required by
56 /// PreprocessorOptions::PrecompiledPreambleBytes.
57 /// The preamble includes the BOM, if any.
59  /// Size of the preamble in bytes.
60  unsigned Size;
61 
62  /// Whether the preamble ends at the start of a new line.
63  ///
64  /// Used to inform the lexer as to whether it's starting at the beginning of
65  /// a line after skipping the preamble.
67 
70 };
71 
72 /// Lexer - This provides a simple interface that turns a text buffer into a
73 /// stream of tokens. This provides no support for file reading or buffering,
74 /// or buffering/seeking of tokens, only forward lexing is supported. It relies
75 /// on the specified Preprocessor object to handle preprocessor directives, etc.
76 class Lexer : public PreprocessorLexer {
77  friend class Preprocessor;
78 
79  void anchor() override;
80 
81  //===--------------------------------------------------------------------===//
82  // Constant configuration values for this lexer.
83 
84  // Start of the buffer.
85  const char *BufferStart;
86 
87  // End of the buffer.
88  const char *BufferEnd;
89 
90  // Location for start of file.
91  SourceLocation FileLoc;
92 
93  // LangOpts enabled by this language (cache).
94  LangOptions LangOpts;
95 
96  // True if lexer for _Pragma handling.
97  bool Is_PragmaLexer;
98 
99  //===--------------------------------------------------------------------===//
100  // Context-specific lexing flags set by the preprocessor.
101  //
102 
103  /// ExtendedTokenMode - The lexer can optionally keep comments and whitespace
104  /// and return them as tokens. This is used for -C and -CC modes, and
105  /// whitespace preservation can be useful for some clients that want to lex
106  /// the file in raw mode and get every character from the file.
107  ///
108  /// When this is set to 2 it returns comments and whitespace. When set to 1
109  /// it returns comments, when it is set to 0 it returns normal tokens only.
110  unsigned char ExtendedTokenMode;
111 
112  //===--------------------------------------------------------------------===//
113  // Context that changes as the file is lexed.
114  // NOTE: any state that mutates when in raw mode must have save/restore code
115  // in Lexer::isNextPPTokenLParen.
116 
117  // BufferPtr - Current pointer into the buffer. This is the next character
118  // to be lexed.
119  const char *BufferPtr;
120 
121  // IsAtStartOfLine - True if the next lexed token should get the "start of
122  // line" flag set on it.
123  bool IsAtStartOfLine;
124 
125  bool IsAtPhysicalStartOfLine;
126 
127  bool HasLeadingSpace;
128 
129  bool HasLeadingEmptyMacro;
130 
131  /// True if this is the first time we're lexing the input file.
132  bool IsFirstTimeLexingFile;
133 
134  // NewLinePtr - A pointer to new line character '\n' being lexed. For '\r\n',
135  // it also points to '\n.'
136  const char *NewLinePtr;
137 
138  // CurrentConflictMarkerState - The kind of conflict marker we are handling.
139  ConflictMarkerKind CurrentConflictMarkerState;
140 
141  void InitLexer(const char *BufStart, const char *BufPtr, const char *BufEnd);
142 
143 public:
144  /// Lexer constructor - Create a new lexer object for the specified buffer
145  /// with the specified preprocessor managing the lexing process. This lexer
146  /// assumes that the associated file buffer and Preprocessor objects will
147  /// outlive it, so it doesn't take ownership of either of them.
148  Lexer(FileID FID, const llvm::MemoryBufferRef &InputFile, Preprocessor &PP,
149  bool IsFirstIncludeOfFile = true);
150 
151  /// Lexer constructor - Create a new raw lexer object. This object is only
152  /// suitable for calls to 'LexFromRawLexer'. This lexer assumes that the
153  /// text range will outlive it, so it doesn't take ownership of it.
154  Lexer(SourceLocation FileLoc, const LangOptions &LangOpts,
155  const char *BufStart, const char *BufPtr, const char *BufEnd,
156  bool IsFirstIncludeOfFile = true);
157 
158  /// Lexer constructor - Create a new raw lexer object. This object is only
159  /// suitable for calls to 'LexFromRawLexer'. This lexer assumes that the
160  /// text range will outlive it, so it doesn't take ownership of it.
161  Lexer(FileID FID, const llvm::MemoryBufferRef &FromFile,
162  const SourceManager &SM, const LangOptions &LangOpts,
163  bool IsFirstIncludeOfFile = true);
164 
165  Lexer(const Lexer &) = delete;
166  Lexer &operator=(const Lexer &) = delete;
167 
168  /// Create_PragmaLexer: Lexer constructor - Create a new lexer object for
169  /// _Pragma expansion. This has a variety of magic semantics that this method
170  /// sets up. It returns a new'd Lexer that must be delete'd when done.
171  static Lexer *Create_PragmaLexer(SourceLocation SpellingLoc,
172  SourceLocation ExpansionLocStart,
173  SourceLocation ExpansionLocEnd,
174  unsigned TokLen, Preprocessor &PP);
175 
176  /// getLangOpts - Return the language features currently enabled.
177  /// NOTE: this lexer modifies features as a file is parsed!
178  const LangOptions &getLangOpts() const { return LangOpts; }
179 
180  /// getFileLoc - Return the File Location for the file we are lexing out of.
181  /// The physical location encodes the location where the characters come from,
182  /// the virtual location encodes where we should *claim* the characters came
183  /// from. Currently this is only used by _Pragma handling.
184  SourceLocation getFileLoc() const { return FileLoc; }
185 
186 private:
187  /// Lex - Return the next token in the file. If this is the end of file, it
188  /// return the tok::eof token. This implicitly involves the preprocessor.
189  bool Lex(Token &Result);
190 
191 public:
192  /// isPragmaLexer - Returns true if this Lexer is being used to lex a pragma.
193  bool isPragmaLexer() const { return Is_PragmaLexer; }
194 
195 private:
196  /// IndirectLex - An indirect call to 'Lex' that can be invoked via
197  /// the PreprocessorLexer interface.
198  void IndirectLex(Token &Result) override { Lex(Result); }
199 
200 public:
201  /// LexFromRawLexer - Lex a token from a designated raw lexer (one with no
202  /// associated preprocessor object. Return true if the 'next character to
203  /// read' pointer points at the end of the lexer buffer, false otherwise.
204  bool LexFromRawLexer(Token &Result) {
205  assert(LexingRawMode && "Not already in raw mode!");
206  Lex(Result);
207  // Note that lexing to the end of the buffer doesn't implicitly delete the
208  // lexer when in raw mode.
209  return BufferPtr == BufferEnd;
210  }
211 
212  /// isKeepWhitespaceMode - Return true if the lexer should return tokens for
213  /// every character in the file, including whitespace and comments. This
214  /// should only be used in raw mode, as the preprocessor is not prepared to
215  /// deal with the excess tokens.
216  bool isKeepWhitespaceMode() const {
217  return ExtendedTokenMode > 1;
218  }
219 
220  /// SetKeepWhitespaceMode - This method lets clients enable or disable
221  /// whitespace retention mode.
222  void SetKeepWhitespaceMode(bool Val) {
223  assert((!Val || LexingRawMode || LangOpts.TraditionalCPP) &&
224  "Can only retain whitespace in raw mode or -traditional-cpp");
225  ExtendedTokenMode = Val ? 2 : 0;
226  }
227 
228  /// inKeepCommentMode - Return true if the lexer should return comments as
229  /// tokens.
230  bool inKeepCommentMode() const {
231  return ExtendedTokenMode > 0;
232  }
233 
234  /// SetCommentRetentionMode - Change the comment retention mode of the lexer
235  /// to the specified mode. This is really only useful when lexing in raw
236  /// mode, because otherwise the lexer needs to manage this.
237  void SetCommentRetentionState(bool Mode) {
238  assert(!isKeepWhitespaceMode() &&
239  "Can't play with comment retention state when retaining whitespace");
240  ExtendedTokenMode = Mode ? 1 : 0;
241  }
242 
243  /// Sets the extended token mode back to its initial value, according to the
244  /// language options and preprocessor. This controls whether the lexer
245  /// produces comment and whitespace tokens.
246  ///
247  /// This requires the lexer to have an associated preprocessor. A standalone
248  /// lexer has nothing to reset to.
249  void resetExtendedTokenMode();
250 
251  /// Gets source code buffer.
252  StringRef getBuffer() const {
253  return StringRef(BufferStart, BufferEnd - BufferStart);
254  }
255 
256  /// ReadToEndOfLine - Read the rest of the current preprocessor line as an
257  /// uninterpreted string. This switches the lexer out of directive mode.
258  void ReadToEndOfLine(SmallVectorImpl<char> *Result = nullptr);
259 
260 
261  /// Diag - Forwarding function for diagnostics. This translate a source
262  /// position in the current buffer into a SourceLocation object for rendering.
263  DiagnosticBuilder Diag(const char *Loc, unsigned DiagID) const;
264 
265  /// getSourceLocation - Return a source location identifier for the specified
266  /// offset in the current file.
267  SourceLocation getSourceLocation(const char *Loc, unsigned TokLen = 1) const;
268 
269  /// getSourceLocation - Return a source location for the next character in
270  /// the current file.
272  return getSourceLocation(BufferPtr);
273  }
274 
275  /// Return the current location in the buffer.
276  const char *getBufferLocation() const { return BufferPtr; }
277 
278  /// Returns the current lexing offset.
280  assert(BufferPtr >= BufferStart && "Invalid buffer state");
281  return BufferPtr - BufferStart;
282  }
283 
284  /// Skip over \p NumBytes bytes.
285  ///
286  /// If the skip is successful, the next token will be lexed from the new
287  /// offset. The lexer also assumes that we skipped to the start of the line.
288  ///
289  /// \returns true if the skip failed (new offset would have been past the
290  /// end of the buffer), false otherwise.
291  bool skipOver(unsigned NumBytes);
292 
293  /// Stringify - Convert the specified string into a C string by i) escaping
294  /// '\\' and " characters and ii) replacing newline character(s) with "\\n".
295  /// If Charify is true, this escapes the ' character instead of ".
296  static std::string Stringify(StringRef Str, bool Charify = false);
297 
298  /// Stringify - Convert the specified string into a C string by i) escaping
299  /// '\\' and " characters and ii) replacing newline character(s) with "\\n".
300  static void Stringify(SmallVectorImpl<char> &Str);
301 
302  /// getSpelling - This method is used to get the spelling of a token into a
303  /// preallocated buffer, instead of as an std::string. The caller is required
304  /// to allocate enough space for the token, which is guaranteed to be at least
305  /// Tok.getLength() bytes long. The length of the actual result is returned.
306  ///
307  /// Note that this method may do two possible things: it may either fill in
308  /// the buffer specified with characters, or it may *change the input pointer*
309  /// to point to a constant buffer with the data already in it (avoiding a
310  /// copy). The caller is not allowed to modify the returned buffer pointer
311  /// if an internal buffer is returned.
312  static unsigned getSpelling(const Token &Tok, const char *&Buffer,
313  const SourceManager &SourceMgr,
314  const LangOptions &LangOpts,
315  bool *Invalid = nullptr);
316 
317  /// getSpelling() - Return the 'spelling' of the Tok token. The spelling of a
318  /// token is the characters used to represent the token in the source file
319  /// after trigraph expansion and escaped-newline folding. In particular, this
320  /// wants to get the true, uncanonicalized, spelling of things like digraphs
321  /// UCNs, etc.
322  static std::string getSpelling(const Token &Tok,
323  const SourceManager &SourceMgr,
324  const LangOptions &LangOpts,
325  bool *Invalid = nullptr);
326 
327  /// getSpelling - This method is used to get the spelling of the
328  /// token at the given source location. If, as is usually true, it
329  /// is not necessary to copy any data, then the returned string may
330  /// not point into the provided buffer.
331  ///
332  /// This method lexes at the expansion depth of the given
333  /// location and does not jump to the expansion or spelling
334  /// location.
335  static StringRef getSpelling(SourceLocation loc,
336  SmallVectorImpl<char> &buffer,
337  const SourceManager &SM,
338  const LangOptions &options,
339  bool *invalid = nullptr);
340 
341  /// MeasureTokenLength - Relex the token at the specified location and return
342  /// its length in bytes in the input file. If the token needs cleaning (e.g.
343  /// includes a trigraph or an escaped newline) then this count includes bytes
344  /// that are part of that.
345  static unsigned MeasureTokenLength(SourceLocation Loc,
346  const SourceManager &SM,
347  const LangOptions &LangOpts);
348 
349  /// Relex the token at the specified location.
350  /// \returns true if there was a failure, false on success.
351  static bool getRawToken(SourceLocation Loc, Token &Result,
352  const SourceManager &SM,
353  const LangOptions &LangOpts,
354  bool IgnoreWhiteSpace = false);
355 
356  /// Given a location any where in a source buffer, find the location
357  /// that corresponds to the beginning of the token in which the original
358  /// source location lands.
360  const SourceManager &SM,
361  const LangOptions &LangOpts);
362 
363  /// Get the physical length (including trigraphs and escaped newlines) of the
364  /// first \p Characters characters of the token starting at TokStart.
365  static unsigned getTokenPrefixLength(SourceLocation TokStart,
366  unsigned CharNo,
367  const SourceManager &SM,
368  const LangOptions &LangOpts);
369 
370  /// AdvanceToTokenCharacter - If the current SourceLocation specifies a
371  /// location at the start of a token, return a new location that specifies a
372  /// character within the token. This handles trigraphs and escaped newlines.
374  unsigned Characters,
375  const SourceManager &SM,
376  const LangOptions &LangOpts) {
377  return TokStart.getLocWithOffset(
378  getTokenPrefixLength(TokStart, Characters, SM, LangOpts));
379  }
380 
381  /// Computes the source location just past the end of the
382  /// token at this source location.
383  ///
384  /// This routine can be used to produce a source location that
385  /// points just past the end of the token referenced by \p Loc, and
386  /// is generally used when a diagnostic needs to point just after a
387  /// token where it expected something different that it received. If
388  /// the returned source location would not be meaningful (e.g., if
389  /// it points into a macro), this routine returns an invalid
390  /// source location.
391  ///
392  /// \param Offset an offset from the end of the token, where the source
393  /// location should refer to. The default offset (0) produces a source
394  /// location pointing just past the end of the token; an offset of 1 produces
395  /// a source location pointing to the last character in the token, etc.
397  const SourceManager &SM,
398  const LangOptions &LangOpts);
399 
400  /// Given a token range, produce a corresponding CharSourceRange that
401  /// is not a token range. This allows the source range to be used by
402  /// components that don't have access to the lexer and thus can't find the
403  /// end of the range for themselves.
405  const SourceManager &SM,
406  const LangOptions &LangOpts) {
407  SourceLocation End = getLocForEndOfToken(Range.getEnd(), 0, SM, LangOpts);
408  return End.isInvalid() ? CharSourceRange()
410  Range.getBegin(), End);
411  }
413  const SourceManager &SM,
414  const LangOptions &LangOpts) {
415  return Range.isTokenRange()
416  ? getAsCharRange(Range.getAsRange(), SM, LangOpts)
417  : Range;
418  }
419 
420  /// Returns true if the given MacroID location points at the first
421  /// token of the macro expansion.
422  ///
423  /// \param MacroBegin If non-null and function returns true, it is set to
424  /// begin location of the macro.
426  const SourceManager &SM,
427  const LangOptions &LangOpts,
428  SourceLocation *MacroBegin = nullptr);
429 
430  /// Returns true if the given MacroID location points at the last
431  /// token of the macro expansion.
432  ///
433  /// \param MacroEnd If non-null and function returns true, it is set to
434  /// end location of the macro.
435  static bool isAtEndOfMacroExpansion(SourceLocation loc,
436  const SourceManager &SM,
437  const LangOptions &LangOpts,
438  SourceLocation *MacroEnd = nullptr);
439 
440  /// Accepts a range and returns a character range with file locations.
441  ///
442  /// Returns a null range if a part of the range resides inside a macro
443  /// expansion or the range does not reside on the same FileID.
444  ///
445  /// This function is trying to deal with macros and return a range based on
446  /// file locations. The cases where it can successfully handle macros are:
447  ///
448  /// -begin or end range lies at the start or end of a macro expansion, in
449  /// which case the location will be set to the expansion point, e.g:
450  /// \#define M 1 2
451  /// a M
452  /// If you have a range [a, 2] (where 2 came from the macro), the function
453  /// will return a range for "a M"
454  /// if you have range [a, 1], the function will fail because the range
455  /// overlaps with only a part of the macro
456  ///
457  /// -The macro is a function macro and the range can be mapped to the macro
458  /// arguments, e.g:
459  /// \#define M 1 2
460  /// \#define FM(x) x
461  /// FM(a b M)
462  /// if you have range [b, 2], the function will return the file range "b M"
463  /// inside the macro arguments.
464  /// if you have range [a, 2], the function will return the file range
465  /// "FM(a b M)" since the range includes all of the macro expansion.
467  const SourceManager &SM,
468  const LangOptions &LangOpts);
469 
470  /// Returns a string for the source that the range encompasses.
471  static StringRef getSourceText(CharSourceRange Range,
472  const SourceManager &SM,
473  const LangOptions &LangOpts,
474  bool *Invalid = nullptr);
475 
476  /// Retrieve the name of the immediate macro expansion.
477  ///
478  /// This routine starts from a source location, and finds the name of the macro
479  /// responsible for its immediate expansion. It looks through any intervening
480  /// macro argument expansions to compute this. It returns a StringRef which
481  /// refers to the SourceManager-owned buffer of the source where that macro
482  /// name is spelled. Thus, the result shouldn't out-live that SourceManager.
483  static StringRef getImmediateMacroName(SourceLocation Loc,
484  const SourceManager &SM,
485  const LangOptions &LangOpts);
486 
487  /// Retrieve the name of the immediate macro expansion.
488  ///
489  /// This routine starts from a source location, and finds the name of the
490  /// macro responsible for its immediate expansion. It looks through any
491  /// intervening macro argument expansions to compute this. It returns a
492  /// StringRef which refers to the SourceManager-owned buffer of the source
493  /// where that macro name is spelled. Thus, the result shouldn't out-live
494  /// that SourceManager.
495  ///
496  /// This differs from Lexer::getImmediateMacroName in that any macro argument
497  /// location will result in the topmost function macro that accepted it.
498  /// e.g.
499  /// \code
500  /// MAC1( MAC2(foo) )
501  /// \endcode
502  /// for location of 'foo' token, this function will return "MAC1" while
503  /// Lexer::getImmediateMacroName will return "MAC2".
504  static StringRef getImmediateMacroNameForDiagnostics(
505  SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts);
506 
507  /// Compute the preamble of the given file.
508  ///
509  /// The preamble of a file contains the initial comments, include directives,
510  /// and other preprocessor directives that occur before the code in this
511  /// particular file actually begins. The preamble of the main source file is
512  /// a potential prefix header.
513  ///
514  /// \param Buffer The memory buffer containing the file's contents.
515  ///
516  /// \param MaxLines If non-zero, restrict the length of the preamble
517  /// to fewer than this number of lines.
518  ///
519  /// \returns The offset into the file where the preamble ends and the rest
520  /// of the file begins along with a boolean value indicating whether
521  /// the preamble ends at the beginning of a new line.
522  static PreambleBounds ComputePreamble(StringRef Buffer,
523  const LangOptions &LangOpts,
524  unsigned MaxLines = 0);
525 
526  /// Finds the token that comes right after the given location.
527  ///
528  /// Returns the next token, or none if the location is inside a macro.
530  const SourceManager &SM,
531  const LangOptions &LangOpts);
532 
533  /// Checks that the given token is the first token that occurs after
534  /// the given location (this excludes comments and whitespace). Returns the
535  /// location immediately after the specified token. If the token is not found
536  /// or the location is inside a macro, the returned source location will be
537  /// invalid.
539  tok::TokenKind TKind,
540  const SourceManager &SM,
541  const LangOptions &LangOpts,
542  bool SkipTrailingWhitespaceAndNewLine);
543 
544  /// Returns true if the given character could appear in an identifier.
545  static bool isAsciiIdentifierContinueChar(char c,
546  const LangOptions &LangOpts);
547 
548  /// Checks whether new line pointed by Str is preceded by escape
549  /// sequence.
550  static bool isNewLineEscaped(const char *BufferStart, const char *Str);
551 
552  /// getCharAndSizeNoWarn - Like the getCharAndSize method, but does not ever
553  /// emit a warning.
554  static inline char getCharAndSizeNoWarn(const char *Ptr, unsigned &Size,
555  const LangOptions &LangOpts) {
556  // If this is not a trigraph and not a UCN or escaped newline, return
557  // quickly.
558  if (isObviouslySimpleCharacter(Ptr[0])) {
559  Size = 1;
560  return *Ptr;
561  }
562 
563  Size = 0;
564  return getCharAndSizeSlowNoWarn(Ptr, Size, LangOpts);
565  }
566 
567  /// Returns the leading whitespace for line that corresponds to the given
568  /// location \p Loc.
569  static StringRef getIndentationForLine(SourceLocation Loc,
570  const SourceManager &SM);
571 
572  /// Check if this is the first time we're lexing the input file.
573  bool isFirstTimeLexingFile() const { return IsFirstTimeLexingFile; }
574 
575 private:
576  //===--------------------------------------------------------------------===//
577  // Internal implementation interfaces.
578 
579  /// LexTokenInternal - Internal interface to lex a preprocessing token. Called
580  /// by Lex.
581  ///
582  bool LexTokenInternal(Token &Result, bool TokAtPhysicalStartOfLine);
583 
584  bool CheckUnicodeWhitespace(Token &Result, uint32_t C, const char *CurPtr);
585 
586  bool LexUnicodeIdentifierStart(Token &Result, uint32_t C, const char *CurPtr);
587 
588  /// FormTokenWithChars - When we lex a token, we have identified a span
589  /// starting at BufferPtr, going to TokEnd that forms the token. This method
590  /// takes that range and assigns it to the token as its location and size. In
591  /// addition, since tokens cannot overlap, this also updates BufferPtr to be
592  /// TokEnd.
593  void FormTokenWithChars(Token &Result, const char *TokEnd,
595  unsigned TokLen = TokEnd-BufferPtr;
596  Result.setLength(TokLen);
597  Result.setLocation(getSourceLocation(BufferPtr, TokLen));
598  Result.setKind(Kind);
599  BufferPtr = TokEnd;
600  }
601 
602  /// isNextPPTokenLParen - Return 1 if the next unexpanded token will return a
603  /// tok::l_paren token, 0 if it is something else and 2 if there are no more
604  /// tokens in the buffer controlled by this lexer.
605  unsigned isNextPPTokenLParen();
606 
607  //===--------------------------------------------------------------------===//
608  // Lexer character reading interfaces.
609 
610  // This lexer is built on two interfaces for reading characters, both of which
611  // automatically provide phase 1/2 translation. getAndAdvanceChar is used
612  // when we know that we will be reading a character from the input buffer and
613  // that this character will be part of the result token. This occurs in (f.e.)
614  // string processing, because we know we need to read until we find the
615  // closing '"' character.
616  //
617  // The second interface is the combination of getCharAndSize with
618  // ConsumeChar. getCharAndSize reads a phase 1/2 translated character,
619  // returning it and its size. If the lexer decides that this character is
620  // part of the current token, it calls ConsumeChar on it. This two stage
621  // approach allows us to emit diagnostics for characters (e.g. warnings about
622  // trigraphs), knowing that they only are emitted if the character is
623  // consumed.
624 
625  /// isObviouslySimpleCharacter - Return true if the specified character is
626  /// obviously the same in translation phase 1 and translation phase 3. This
627  /// can return false for characters that end up being the same, but it will
628  /// never return true for something that needs to be mapped.
629  static bool isObviouslySimpleCharacter(char C) {
630  return C != '?' && C != '\\';
631  }
632 
633  /// getAndAdvanceChar - Read a single 'character' from the specified buffer,
634  /// advance over it, and return it. This is tricky in several cases. Here we
635  /// just handle the trivial case and fall-back to the non-inlined
636  /// getCharAndSizeSlow method to handle the hard case.
637  inline char getAndAdvanceChar(const char *&Ptr, Token &Tok) {
638  // If this is not a trigraph and not a UCN or escaped newline, return
639  // quickly.
640  if (isObviouslySimpleCharacter(Ptr[0])) return *Ptr++;
641 
642  unsigned Size = 0;
643  char C = getCharAndSizeSlow(Ptr, Size, &Tok);
644  Ptr += Size;
645  return C;
646  }
647 
648  /// ConsumeChar - When a character (identified by getCharAndSize) is consumed
649  /// and added to a given token, check to see if there are diagnostics that
650  /// need to be emitted or flags that need to be set on the token. If so, do
651  /// it.
652  const char *ConsumeChar(const char *Ptr, unsigned Size, Token &Tok) {
653  // Normal case, we consumed exactly one token. Just return it.
654  if (Size == 1)
655  return Ptr+Size;
656 
657  // Otherwise, re-lex the character with a current token, allowing
658  // diagnostics to be emitted and flags to be set.
659  Size = 0;
660  getCharAndSizeSlow(Ptr, Size, &Tok);
661  return Ptr+Size;
662  }
663 
664  /// getCharAndSize - Peek a single 'character' from the specified buffer,
665  /// get its size, and return it. This is tricky in several cases. Here we
666  /// just handle the trivial case and fall-back to the non-inlined
667  /// getCharAndSizeSlow method to handle the hard case.
668  inline char getCharAndSize(const char *Ptr, unsigned &Size) {
669  // If this is not a trigraph and not a UCN or escaped newline, return
670  // quickly.
671  if (isObviouslySimpleCharacter(Ptr[0])) {
672  Size = 1;
673  return *Ptr;
674  }
675 
676  Size = 0;
677  return getCharAndSizeSlow(Ptr, Size);
678  }
679 
680  /// getCharAndSizeSlow - Handle the slow/uncommon case of the getCharAndSize
681  /// method.
682  char getCharAndSizeSlow(const char *Ptr, unsigned &Size,
683  Token *Tok = nullptr);
684 
685  /// getEscapedNewLineSize - Return the size of the specified escaped newline,
686  /// or 0 if it is not an escaped newline. P[-1] is known to be a "\" on entry
687  /// to this function.
688  static unsigned getEscapedNewLineSize(const char *P);
689 
690  /// SkipEscapedNewLines - If P points to an escaped newline (or a series of
691  /// them), skip over them and return the first non-escaped-newline found,
692  /// otherwise return P.
693  static const char *SkipEscapedNewLines(const char *P);
694 
695  /// getCharAndSizeSlowNoWarn - Same as getCharAndSizeSlow, but never emits a
696  /// diagnostic.
697  static char getCharAndSizeSlowNoWarn(const char *Ptr, unsigned &Size,
698  const LangOptions &LangOpts);
699 
700  //===--------------------------------------------------------------------===//
701  // Other lexer functions.
702 
703  void SetByteOffset(unsigned Offset, bool StartOfLine);
704 
705  void PropagateLineStartLeadingSpaceInfo(Token &Result);
706 
707  const char *LexUDSuffix(Token &Result, const char *CurPtr,
708  bool IsStringLiteral);
709 
710  // Helper functions to lex the remainder of a token of the specific type.
711 
712  // This function handles both ASCII and Unicode identifiers after
713  // the first codepoint of the identifyier has been parsed.
714  bool LexIdentifierContinue(Token &Result, const char *CurPtr);
715 
716  bool LexNumericConstant (Token &Result, const char *CurPtr);
717  bool LexStringLiteral (Token &Result, const char *CurPtr,
719  bool LexRawStringLiteral (Token &Result, const char *CurPtr,
721  bool LexAngledStringLiteral(Token &Result, const char *CurPtr);
722  bool LexCharConstant (Token &Result, const char *CurPtr,
724  bool LexEndOfFile (Token &Result, const char *CurPtr);
725  bool SkipWhitespace (Token &Result, const char *CurPtr,
726  bool &TokAtPhysicalStartOfLine);
727  bool SkipLineComment (Token &Result, const char *CurPtr,
728  bool &TokAtPhysicalStartOfLine);
729  bool SkipBlockComment (Token &Result, const char *CurPtr,
730  bool &TokAtPhysicalStartOfLine);
731  bool SaveLineComment (Token &Result, const char *CurPtr);
732 
733  bool IsStartOfConflictMarker(const char *CurPtr);
734  bool HandleEndOfConflictMarker(const char *CurPtr);
735 
736  bool lexEditorPlaceholder(Token &Result, const char *CurPtr);
737 
738  bool isCodeCompletionPoint(const char *CurPtr) const;
739  void cutOffLexing() { BufferPtr = BufferEnd; }
740 
741  bool isHexaLiteral(const char *Start, const LangOptions &LangOpts);
742 
743  void codeCompleteIncludedFile(const char *PathStart,
744  const char *CompletionPoint, bool IsAngled);
745 
746  /// Read a universal character name.
747  ///
748  /// \param StartPtr The position in the source buffer after the initial '\'.
749  /// If the UCN is syntactically well-formed (but not
750  /// necessarily valid), this parameter will be updated to
751  /// point to the character after the UCN.
752  /// \param SlashLoc The position in the source buffer of the '\'.
753  /// \param Result The token being formed. Pass \c nullptr to suppress
754  /// diagnostics and handle token formation in the caller.
755  ///
756  /// \return The Unicode codepoint specified by the UCN, or 0 if the UCN is
757  /// invalid.
758  uint32_t tryReadUCN(const char *&StartPtr, const char *SlashLoc, Token *Result);
759 
760  /// Try to consume a UCN as part of an identifier at the current
761  /// location.
762  /// \param CurPtr Initially points to the range of characters in the source
763  /// buffer containing the '\'. Updated to point past the end of
764  /// the UCN on success.
765  /// \param Size The number of characters occupied by the '\' (including
766  /// trigraphs and escaped newlines).
767  /// \param Result The token being produced. Marked as containing a UCN on
768  /// success.
769  /// \return \c true if a UCN was lexed and it produced an acceptable
770  /// identifier character, \c false otherwise.
771  bool tryConsumeIdentifierUCN(const char *&CurPtr, unsigned Size,
772  Token &Result);
773 
774  /// Try to consume an identifier character encoded in UTF-8.
775  /// \param CurPtr Points to the start of the (potential) UTF-8 code unit
776  /// sequence. On success, updated to point past the end of it.
777  /// \return \c true if a UTF-8 sequence mapping to an acceptable identifier
778  /// character was lexed, \c false otherwise.
779  bool tryConsumeIdentifierUTF8Char(const char *&CurPtr);
780 };
781 
782 } // namespace clang
783 
784 #endif // LLVM_CLANG_LEX_LEXER_H
clang::Lexer::isAtEndOfMacroExpansion
static bool isAtEndOfMacroExpansion(SourceLocation loc, const SourceManager &SM, const LangOptions &LangOpts, SourceLocation *MacroEnd=nullptr)
Returns true if the given MacroID location points at the last token of the macro expansion.
Definition: Lexer.cpp:831
clang::Lexer::makeFileCharRange
static CharSourceRange makeFileCharRange(CharSourceRange Range, const SourceManager &SM, const LangOptions &LangOpts)
Accepts a range and returns a character range with file locations.
Definition: Lexer.cpp:892
PreprocessorLexer.h
llvm
YAML serialization mapping.
Definition: Dominators.h:30
clang::Lexer::SetCommentRetentionState
void SetCommentRetentionState(bool Mode)
SetCommentRetentionMode - Change the comment retention mode of the lexer to the specified mode.
Definition: Lexer.h:237
clang::DiagnosticBuilder
A little helper class used to produce diagnostics.
Definition: Diagnostic.h:1264
clang::CMK_Perforce
@ CMK_Perforce
A Perforce-style conflict marker, initiated by 4 ">"s, separated by 4 "="s, and terminated by 4 "<"s.
Definition: Lexer.h:52
clang::SourceRange
A trivial tuple used to represent a source range.
Definition: SourceLocation.h:210
string
string(SUBSTRING ${CMAKE_CURRENT_BINARY_DIR} 0 ${PATH_LIB_START} PATH_HEAD) string(SUBSTRING $
Definition: CMakeLists.txt:22
clang::Lexer::getLangOpts
const LangOptions & getLangOpts() const
getLangOpts - Return the language features currently enabled.
Definition: Lexer.h:178
clang::Lexer::getRawToken
static bool getRawToken(SourceLocation Loc, Token &Result, const SourceManager &SM, const LangOptions &LangOpts, bool IgnoreWhiteSpace=false)
Relex the token at the specified location.
Definition: Lexer.cpp:462
clang::Lexer::isAsciiIdentifierContinueChar
static bool isAsciiIdentifierContinueChar(char c, const LangOptions &LangOpts)
Returns true if the given character could appear in an identifier.
Definition: Lexer.cpp:1069
clang::ConflictMarkerKind
ConflictMarkerKind
ConflictMarkerKind - Kinds of conflict marker which the lexer might be recovering from.
Definition: Lexer.h:42
clang::Lexer::getSpelling
static unsigned getSpelling(const Token &Tok, const char *&Buffer, const SourceManager &SourceMgr, const LangOptions &LangOpts, bool *Invalid=nullptr)
getSpelling - This method is used to get the spelling of a token into a preallocated buffer,...
Definition: Lexer.cpp:404
clang::SourceLocation
Encodes a location in the source.
Definition: SourceLocation.h:86
clang::SourceLocation::getLocWithOffset
SourceLocation getLocWithOffset(IntTy Offset) const
Return a source location with the specified offset from this SourceLocation.
Definition: SourceLocation.h:134
clang::Lexer::getFileLoc
SourceLocation getFileLoc() const
getFileLoc - Return the File Location for the file we are lexing out of.
Definition: Lexer.h:184
clang::Lexer::inKeepCommentMode
bool inKeepCommentMode() const
inKeepCommentMode - Return true if the lexer should return comments as tokens.
Definition: Lexer.h:230
clang::PreprocessorLexer
Definition: PreprocessorLexer.h:31
clang::Lexer::Create_PragmaLexer
static Lexer * Create_PragmaLexer(SourceLocation SpellingLoc, SourceLocation ExpansionLocStart, SourceLocation ExpansionLocEnd, unsigned TokLen, Preprocessor &PP)
Create_PragmaLexer: Lexer constructor - Create a new lexer object for _Pragma expansion.
Definition: Lexer.cpp:193
AttributeLangSupport::C
@ C
Definition: SemaDeclAttr.cpp:54
llvm::Optional
Definition: LLVM.h:40
clang::Lexer::getSourceText
static StringRef getSourceText(CharSourceRange Range, const SourceManager &SM, const LangOptions &LangOpts, bool *Invalid=nullptr)
Returns a string for the source that the range encompasses.
Definition: Lexer.cpp:961
clang::Lexer::skipOver
bool skipOver(unsigned NumBytes)
Skip over NumBytes bytes.
Definition: Lexer.cpp:228
clang::PreprocessorLexer::LexingRawMode
bool LexingRawMode
True if in raw mode.
Definition: PreprocessorLexer.h:69
clang::Lexer::isKeepWhitespaceMode
bool isKeepWhitespaceMode() const
isKeepWhitespaceMode - Return true if the lexer should return tokens for every character in the file,...
Definition: Lexer.h:216
clang::Lexer::MeasureTokenLength
static unsigned MeasureTokenLength(SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts)
MeasureTokenLength - Relex the token at the specified location and return its length in bytes in the ...
Definition: Lexer.cpp:451
clang::Lexer::LexFromRawLexer
bool LexFromRawLexer(Token &Result)
LexFromRawLexer - Lex a token from a designated raw lexer (one with no associated preprocessor object...
Definition: Lexer.h:204
clang::Token
Token - This structure provides full information about a lexed token.
Definition: Token.h:34
End
SourceLocation End
Definition: USRLocFinder.cpp:167
clang::SourceManager
This class handles loading and caching of source files into memory.
Definition: SourceManager.h:626
clang::Lexer::Stringify
static std::string Stringify(StringRef Str, bool Charify=false)
Stringify - Convert the specified string into a C string by i) escaping '\' and " characters and ii) ...
Definition: Lexer.cpp:262
clang::Lexer
Lexer - This provides a simple interface that turns a text buffer into a stream of tokens.
Definition: Lexer.h:76
Offset
unsigned Offset
Definition: Format.cpp:2431
TokenKinds.h
clang::CharSourceRange::getCharRange
static CharSourceRange getCharRange(SourceRange R)
Definition: SourceLocation.h:265
clang::CMK_Normal
@ CMK_Normal
A normal or diff3 conflict marker, initiated by at least 7 "<"s, separated by at least 7 "="s or "|"s...
Definition: Lexer.h:48
clang::Lexer::Diag
DiagnosticBuilder Diag(const char *Loc, unsigned DiagID) const
Diag - Forwarding function for diagnostics.
Definition: Lexer.cpp:1167
LangOptions.h
clang::Lexer::isNewLineEscaped
static bool isNewLineEscaped(const char *BufferStart, const char *Str)
Checks whether new line pointed by Str is preceded by escape sequence.
Definition: Lexer.cpp:1073
clang::Lexer::Lexer
Lexer(FileID FID, const llvm::MemoryBufferRef &InputFile, Preprocessor &PP, bool IsFirstIncludeOfFile=true)
Lexer constructor - Create a new lexer object for the specified buffer with the specified preprocesso...
Definition: Lexer.cpp:135
clang::Lexer::getTokenPrefixLength
static unsigned getTokenPrefixLength(SourceLocation TokStart, unsigned CharNo, const SourceManager &SM, const LangOptions &LangOpts)
Get the physical length (including trigraphs and escaped newlines) of the first Characters characters...
Definition: Lexer.cpp:727
clang::Lexer::getIndentationForLine
static StringRef getIndentationForLine(SourceLocation Loc, const SourceManager &SM)
Returns the leading whitespace for line that corresponds to the given location Loc.
Definition: Lexer.cpp:1093
clang::PreambleBounds
Describes the bounds (start, size) of the preamble and a flag required by PreprocessorOptions::Precom...
Definition: Lexer.h:58
clang::PreprocessorLexer::FID
const FileID FID
The SourceManager FileID corresponding to the file being lexed.
Definition: PreprocessorLexer.h:41
clang::PreambleBounds::Size
unsigned Size
Size of the preamble in bytes.
Definition: Lexer.h:60
clang::Lexer::ReadToEndOfLine
void ReadToEndOfLine(SmallVectorImpl< char > *Result=nullptr)
ReadToEndOfLine - Read the rest of the current preprocessor line as an uninterpreted string.
Definition: Lexer.cpp:2802
clang::PreprocessorLexer::PP
Preprocessor * PP
Definition: PreprocessorLexer.h:38
clang::Lexer::findNextToken
static Optional< Token > findNextToken(SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts)
Finds the token that comes right after the given location.
Definition: Lexer.cpp:1259
clang::Lexer::getImmediateMacroName
static StringRef getImmediateMacroName(SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts)
Retrieve the name of the immediate macro expansion.
Definition: Lexer.cpp:997
clang::Lexer::isFirstTimeLexingFile
bool isFirstTimeLexingFile() const
Check if this is the first time we're lexing the input file.
Definition: Lexer.h:573
SourceLocation.h
clang::tok::TokenKind
TokenKind
Provides a simple uniform namespace for tokens from all C languages.
Definition: TokenKinds.h:25
P
StringRef P
Definition: ASTMatchersInternal.cpp:563
clang::Lexer::getBufferLocation
const char * getBufferLocation() const
Return the current location in the buffer.
Definition: Lexer.h:276
clang::syntax::NodeRole::Size
@ Size
clang::PreambleBounds::PreambleBounds
PreambleBounds(unsigned Size, bool PreambleEndsAtStartOfLine)
Definition: Lexer.h:68
clang::Lexer::operator=
Lexer & operator=(const Lexer &)=delete
clang::Lexer::getCurrentBufferOffset
unsigned getCurrentBufferOffset()
Returns the current lexing offset.
Definition: Lexer.h:279
clang::CharSourceRange
Represents a character-granular source range.
Definition: SourceLocation.h:253
clang::LangOptions
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:58
clang::Lexer::SetKeepWhitespaceMode
void SetKeepWhitespaceMode(bool Val)
SetKeepWhitespaceMode - This method lets clients enable or disable whitespace retention mode.
Definition: Lexer.h:222
clang::ObjCPropertyAttribute::Kind
Kind
Definition: DeclObjCCommon.h:22
clang::Lexer::getImmediateMacroNameForDiagnostics
static StringRef getImmediateMacroNameForDiagnostics(SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts)
Retrieve the name of the immediate macro expansion.
Definition: Lexer.cpp:1044
clang::Lexer::getBuffer
StringRef getBuffer() const
Gets source code buffer.
Definition: Lexer.h:252
clang
Definition: CalledOnceCheck.h:17
clang::Lexer::isAtStartOfMacroExpansion
static bool isAtStartOfMacroExpansion(SourceLocation loc, const SourceManager &SM, const LangOptions &LangOpts, SourceLocation *MacroBegin=nullptr)
Returns true if the given MacroID location points at the first token of the macro expansion.
Definition: Lexer.cpp:809
clang::PreambleBounds::PreambleEndsAtStartOfLine
bool PreambleEndsAtStartOfLine
Whether the preamble ends at the start of a new line.
Definition: Lexer.h:66
clang::Lexer::GetBeginningOfToken
static SourceLocation GetBeginningOfToken(SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts)
Given a location any where in a source buffer, find the location that corresponds to the beginning of...
Definition: Lexer.cpp:561
clang::Lexer::isPragmaLexer
bool isPragmaLexer() const
isPragmaLexer - Returns true if this Lexer is being used to lex a pragma.
Definition: Lexer.h:193
clang::FileID
An opaque identifier used by SourceManager which refers to a source file (MemoryBuffer) along with it...
Definition: SourceLocation.h:38
clang::Lexer::resetExtendedTokenMode
void resetExtendedTokenMode()
Sets the extended token mode back to its initial value, according to the language options and preproc...
Definition: Lexer.cpp:170
c
__device__ __2f16 float c
Definition: __clang_hip_libdevice_declares.h:315
clang::Lexer::AdvanceToTokenCharacter
static SourceLocation AdvanceToTokenCharacter(SourceLocation TokStart, unsigned Characters, const SourceManager &SM, const LangOptions &LangOpts)
AdvanceToTokenCharacter - If the current SourceLocation specifies a location at the start of a token,...
Definition: Lexer.h:373
clang::Lexer::getLocForEndOfToken
static SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset, const SourceManager &SM, const LangOptions &LangOpts)
Computes the source location just past the end of the token at this source location.
Definition: Lexer.cpp:787
clang::Lexer::ComputePreamble
static PreambleBounds ComputePreamble(StringRef Buffer, const LangOptions &LangOpts, unsigned MaxLines=0)
Compute the preamble of the given file.
Definition: Lexer.cpp:589
llvm::SmallVectorImpl< char >
clang::Lexer::findLocationAfterToken
static SourceLocation findLocationAfterToken(SourceLocation loc, tok::TokenKind TKind, const SourceManager &SM, const LangOptions &LangOpts, bool SkipTrailingWhitespaceAndNewLine)
Checks that the given token is the first token that occurs after the given location (this excludes co...
Definition: Lexer.cpp:1292
clang::Lexer::getCharAndSizeNoWarn
static char getCharAndSizeNoWarn(const char *Ptr, unsigned &Size, const LangOptions &LangOpts)
getCharAndSizeNoWarn - Like the getCharAndSize method, but does not ever emit a warning.
Definition: Lexer.h:554
clang::Preprocessor
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:130
SM
#define SM(sm)
Definition: Cuda.cpp:81
clang::Lexer::getSourceLocation
SourceLocation getSourceLocation() override
getSourceLocation - Return a source location for the next character in the current file.
Definition: Lexer.h:271
clang::Lexer::getAsCharRange
static CharSourceRange getAsCharRange(CharSourceRange Range, const SourceManager &SM, const LangOptions &LangOpts)
Definition: Lexer.h:412
Token.h
clang::CMK_None
@ CMK_None
Not within a conflict marker.
Definition: Lexer.h:44
clang::Lexer::getAsCharRange
static CharSourceRange getAsCharRange(SourceRange Range, const SourceManager &SM, const LangOptions &LangOpts)
Given a token range, produce a corresponding CharSourceRange that is not a token range.
Definition: Lexer.h:404