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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 MemoryBuffer;
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 
68  PreambleBounds(unsigned Size, bool PreambleEndsAtStartOfLine)
69  : Size(Size), PreambleEndsAtStartOfLine(PreambleEndsAtStartOfLine) {}
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  // CurrentConflictMarkerState - The kind of conflict marker we are handling.
132  ConflictMarkerKind CurrentConflictMarkerState;
133 
134  void InitLexer(const char *BufStart, const char *BufPtr, const char *BufEnd);
135 
136 public:
137  /// Lexer constructor - Create a new lexer object for the specified buffer
138  /// with the specified preprocessor managing the lexing process. This lexer
139  /// assumes that the associated file buffer and Preprocessor objects will
140  /// outlive it, so it doesn't take ownership of either of them.
141  Lexer(FileID FID, const llvm::MemoryBuffer *InputFile, Preprocessor &PP);
142 
143  /// Lexer constructor - Create a new raw lexer object. This object is only
144  /// suitable for calls to 'LexFromRawLexer'. This lexer assumes that the
145  /// text range will outlive it, so it doesn't take ownership of it.
146  Lexer(SourceLocation FileLoc, const LangOptions &LangOpts,
147  const char *BufStart, const char *BufPtr, const char *BufEnd);
148 
149  /// Lexer constructor - Create a new raw lexer object. This object is only
150  /// suitable for calls to 'LexFromRawLexer'. This lexer assumes that the
151  /// text range will outlive it, so it doesn't take ownership of it.
152  Lexer(FileID FID, const llvm::MemoryBuffer *FromFile,
153  const SourceManager &SM, const LangOptions &LangOpts);
154 
155  Lexer(const Lexer &) = delete;
156  Lexer &operator=(const Lexer &) = delete;
157 
158  /// Create_PragmaLexer: Lexer constructor - Create a new lexer object for
159  /// _Pragma expansion. This has a variety of magic semantics that this method
160  /// sets up. It returns a new'd Lexer that must be delete'd when done.
161  static Lexer *Create_PragmaLexer(SourceLocation SpellingLoc,
162  SourceLocation ExpansionLocStart,
163  SourceLocation ExpansionLocEnd,
164  unsigned TokLen, Preprocessor &PP);
165 
166  /// getLangOpts - Return the language features currently enabled.
167  /// NOTE: this lexer modifies features as a file is parsed!
168  const LangOptions &getLangOpts() const { return LangOpts; }
169 
170  /// getFileLoc - Return the File Location for the file we are lexing out of.
171  /// The physical location encodes the location where the characters come from,
172  /// the virtual location encodes where we should *claim* the characters came
173  /// from. Currently this is only used by _Pragma handling.
174  SourceLocation getFileLoc() const { return FileLoc; }
175 
176 private:
177  /// Lex - Return the next token in the file. If this is the end of file, it
178  /// return the tok::eof token. This implicitly involves the preprocessor.
179  bool Lex(Token &Result);
180 
181 public:
182  /// isPragmaLexer - Returns true if this Lexer is being used to lex a pragma.
183  bool isPragmaLexer() const { return Is_PragmaLexer; }
184 
185 private:
186  /// IndirectLex - An indirect call to 'Lex' that can be invoked via
187  /// the PreprocessorLexer interface.
188  void IndirectLex(Token &Result) override { Lex(Result); }
189 
190 public:
191  /// LexFromRawLexer - Lex a token from a designated raw lexer (one with no
192  /// associated preprocessor object. Return true if the 'next character to
193  /// read' pointer points at the end of the lexer buffer, false otherwise.
194  bool LexFromRawLexer(Token &Result) {
195  assert(LexingRawMode && "Not already in raw mode!");
196  Lex(Result);
197  // Note that lexing to the end of the buffer doesn't implicitly delete the
198  // lexer when in raw mode.
199  return BufferPtr == BufferEnd;
200  }
201 
202  /// isKeepWhitespaceMode - Return true if the lexer should return tokens for
203  /// every character in the file, including whitespace and comments. This
204  /// should only be used in raw mode, as the preprocessor is not prepared to
205  /// deal with the excess tokens.
206  bool isKeepWhitespaceMode() const {
207  return ExtendedTokenMode > 1;
208  }
209 
210  /// SetKeepWhitespaceMode - This method lets clients enable or disable
211  /// whitespace retention mode.
212  void SetKeepWhitespaceMode(bool Val) {
213  assert((!Val || LexingRawMode || LangOpts.TraditionalCPP) &&
214  "Can only retain whitespace in raw mode or -traditional-cpp");
215  ExtendedTokenMode = Val ? 2 : 0;
216  }
217 
218  /// inKeepCommentMode - Return true if the lexer should return comments as
219  /// tokens.
220  bool inKeepCommentMode() const {
221  return ExtendedTokenMode > 0;
222  }
223 
224  /// SetCommentRetentionMode - Change the comment retention mode of the lexer
225  /// to the specified mode. This is really only useful when lexing in raw
226  /// mode, because otherwise the lexer needs to manage this.
227  void SetCommentRetentionState(bool Mode) {
228  assert(!isKeepWhitespaceMode() &&
229  "Can't play with comment retention state when retaining whitespace");
230  ExtendedTokenMode = Mode ? 1 : 0;
231  }
232 
233  /// Sets the extended token mode back to its initial value, according to the
234  /// language options and preprocessor. This controls whether the lexer
235  /// produces comment and whitespace tokens.
236  ///
237  /// This requires the lexer to have an associated preprocessor. A standalone
238  /// lexer has nothing to reset to.
239  void resetExtendedTokenMode();
240 
241  /// Gets source code buffer.
242  StringRef getBuffer() const {
243  return StringRef(BufferStart, BufferEnd - BufferStart);
244  }
245 
246  /// ReadToEndOfLine - Read the rest of the current preprocessor line as an
247  /// uninterpreted string. This switches the lexer out of directive mode.
248  void ReadToEndOfLine(SmallVectorImpl<char> *Result = nullptr);
249 
250 
251  /// Diag - Forwarding function for diagnostics. This translate a source
252  /// position in the current buffer into a SourceLocation object for rendering.
253  DiagnosticBuilder Diag(const char *Loc, unsigned DiagID) const;
254 
255  /// getSourceLocation - Return a source location identifier for the specified
256  /// offset in the current file.
257  SourceLocation getSourceLocation(const char *Loc, unsigned TokLen = 1) const;
258 
259  /// getSourceLocation - Return a source location for the next character in
260  /// the current file.
262  return getSourceLocation(BufferPtr);
263  }
264 
265  /// Return the current location in the buffer.
266  const char *getBufferLocation() const { return BufferPtr; }
267 
268  /// Stringify - Convert the specified string into a C string by i) escaping
269  /// '\\' and " characters and ii) replacing newline character(s) with "\\n".
270  /// If Charify is true, this escapes the ' character instead of ".
271  static std::string Stringify(StringRef Str, bool Charify = false);
272 
273  /// Stringify - Convert the specified string into a C string by i) escaping
274  /// '\\' and " characters and ii) replacing newline character(s) with "\\n".
275  static void Stringify(SmallVectorImpl<char> &Str);
276 
277  /// getSpelling - This method is used to get the spelling of a token into a
278  /// preallocated buffer, instead of as an std::string. The caller is required
279  /// to allocate enough space for the token, which is guaranteed to be at least
280  /// Tok.getLength() bytes long. The length of the actual result is returned.
281  ///
282  /// Note that this method may do two possible things: it may either fill in
283  /// the buffer specified with characters, or it may *change the input pointer*
284  /// to point to a constant buffer with the data already in it (avoiding a
285  /// copy). The caller is not allowed to modify the returned buffer pointer
286  /// if an internal buffer is returned.
287  static unsigned getSpelling(const Token &Tok, const char *&Buffer,
288  const SourceManager &SourceMgr,
289  const LangOptions &LangOpts,
290  bool *Invalid = nullptr);
291 
292  /// getSpelling() - Return the 'spelling' of the Tok token. The spelling of a
293  /// token is the characters used to represent the token in the source file
294  /// after trigraph expansion and escaped-newline folding. In particular, this
295  /// wants to get the true, uncanonicalized, spelling of things like digraphs
296  /// UCNs, etc.
297  static std::string getSpelling(const Token &Tok,
298  const SourceManager &SourceMgr,
299  const LangOptions &LangOpts,
300  bool *Invalid = nullptr);
301 
302  /// getSpelling - This method is used to get the spelling of the
303  /// token at the given source location. If, as is usually true, it
304  /// is not necessary to copy any data, then the returned string may
305  /// not point into the provided buffer.
306  ///
307  /// This method lexes at the expansion depth of the given
308  /// location and does not jump to the expansion or spelling
309  /// location.
310  static StringRef getSpelling(SourceLocation loc,
311  SmallVectorImpl<char> &buffer,
312  const SourceManager &SM,
313  const LangOptions &options,
314  bool *invalid = nullptr);
315 
316  /// MeasureTokenLength - Relex the token at the specified location and return
317  /// its length in bytes in the input file. If the token needs cleaning (e.g.
318  /// includes a trigraph or an escaped newline) then this count includes bytes
319  /// that are part of that.
320  static unsigned MeasureTokenLength(SourceLocation Loc,
321  const SourceManager &SM,
322  const LangOptions &LangOpts);
323 
324  /// Relex the token at the specified location.
325  /// \returns true if there was a failure, false on success.
326  static bool getRawToken(SourceLocation Loc, Token &Result,
327  const SourceManager &SM,
328  const LangOptions &LangOpts,
329  bool IgnoreWhiteSpace = false);
330 
331  /// Given a location any where in a source buffer, find the location
332  /// that corresponds to the beginning of the token in which the original
333  /// source location lands.
334  static SourceLocation GetBeginningOfToken(SourceLocation Loc,
335  const SourceManager &SM,
336  const LangOptions &LangOpts);
337 
338  /// Get the physical length (including trigraphs and escaped newlines) of the
339  /// first \p Characters characters of the token starting at TokStart.
340  static unsigned getTokenPrefixLength(SourceLocation TokStart,
341  unsigned CharNo,
342  const SourceManager &SM,
343  const LangOptions &LangOpts);
344 
345  /// AdvanceToTokenCharacter - If the current SourceLocation specifies a
346  /// location at the start of a token, return a new location that specifies a
347  /// character within the token. This handles trigraphs and escaped newlines.
349  unsigned Characters,
350  const SourceManager &SM,
351  const LangOptions &LangOpts) {
352  return TokStart.getLocWithOffset(
353  getTokenPrefixLength(TokStart, Characters, SM, LangOpts));
354  }
355 
356  /// Computes the source location just past the end of the
357  /// token at this source location.
358  ///
359  /// This routine can be used to produce a source location that
360  /// points just past the end of the token referenced by \p Loc, and
361  /// is generally used when a diagnostic needs to point just after a
362  /// token where it expected something different that it received. If
363  /// the returned source location would not be meaningful (e.g., if
364  /// it points into a macro), this routine returns an invalid
365  /// source location.
366  ///
367  /// \param Offset an offset from the end of the token, where the source
368  /// location should refer to. The default offset (0) produces a source
369  /// location pointing just past the end of the token; an offset of 1 produces
370  /// a source location pointing to the last character in the token, etc.
371  static SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset,
372  const SourceManager &SM,
373  const LangOptions &LangOpts);
374 
375  /// Given a token range, produce a corresponding CharSourceRange that
376  /// is not a token range. This allows the source range to be used by
377  /// components that don't have access to the lexer and thus can't find the
378  /// end of the range for themselves.
380  const SourceManager &SM,
381  const LangOptions &LangOpts) {
382  SourceLocation End = getLocForEndOfToken(Range.getEnd(), 0, SM, LangOpts);
383  return End.isInvalid() ? CharSourceRange()
384  : CharSourceRange::getCharRange(
385  Range.getBegin(), End.getLocWithOffset(-1));
386  }
388  const SourceManager &SM,
389  const LangOptions &LangOpts) {
390  return Range.isTokenRange()
391  ? getAsCharRange(Range.getAsRange(), SM, LangOpts)
392  : Range;
393  }
394 
395  /// Returns true if the given MacroID location points at the first
396  /// token of the macro expansion.
397  ///
398  /// \param MacroBegin If non-null and function returns true, it is set to
399  /// begin location of the macro.
400  static bool isAtStartOfMacroExpansion(SourceLocation loc,
401  const SourceManager &SM,
402  const LangOptions &LangOpts,
403  SourceLocation *MacroBegin = nullptr);
404 
405  /// Returns true if the given MacroID location points at the last
406  /// token of the macro expansion.
407  ///
408  /// \param MacroEnd If non-null and function returns true, it is set to
409  /// end location of the macro.
410  static bool isAtEndOfMacroExpansion(SourceLocation loc,
411  const SourceManager &SM,
412  const LangOptions &LangOpts,
413  SourceLocation *MacroEnd = nullptr);
414 
415  /// Accepts a range and returns a character range with file locations.
416  ///
417  /// Returns a null range if a part of the range resides inside a macro
418  /// expansion or the range does not reside on the same FileID.
419  ///
420  /// This function is trying to deal with macros and return a range based on
421  /// file locations. The cases where it can successfully handle macros are:
422  ///
423  /// -begin or end range lies at the start or end of a macro expansion, in
424  /// which case the location will be set to the expansion point, e.g:
425  /// \#define M 1 2
426  /// a M
427  /// If you have a range [a, 2] (where 2 came from the macro), the function
428  /// will return a range for "a M"
429  /// if you have range [a, 1], the function will fail because the range
430  /// overlaps with only a part of the macro
431  ///
432  /// -The macro is a function macro and the range can be mapped to the macro
433  /// arguments, e.g:
434  /// \#define M 1 2
435  /// \#define FM(x) x
436  /// FM(a b M)
437  /// if you have range [b, 2], the function will return the file range "b M"
438  /// inside the macro arguments.
439  /// if you have range [a, 2], the function will return the file range
440  /// "FM(a b M)" since the range includes all of the macro expansion.
441  static CharSourceRange makeFileCharRange(CharSourceRange Range,
442  const SourceManager &SM,
443  const LangOptions &LangOpts);
444 
445  /// Returns a string for the source that the range encompasses.
446  static StringRef getSourceText(CharSourceRange Range,
447  const SourceManager &SM,
448  const LangOptions &LangOpts,
449  bool *Invalid = nullptr);
450 
451  /// Retrieve the name of the immediate macro expansion.
452  ///
453  /// This routine starts from a source location, and finds the name of the macro
454  /// responsible for its immediate expansion. It looks through any intervening
455  /// macro argument expansions to compute this. It returns a StringRef which
456  /// refers to the SourceManager-owned buffer of the source where that macro
457  /// name is spelled. Thus, the result shouldn't out-live that SourceManager.
458  static StringRef getImmediateMacroName(SourceLocation Loc,
459  const SourceManager &SM,
460  const LangOptions &LangOpts);
461 
462  /// Retrieve the name of the immediate macro expansion.
463  ///
464  /// This routine starts from a source location, and finds the name of the
465  /// macro responsible for its immediate expansion. It looks through any
466  /// intervening macro argument expansions to compute this. It returns a
467  /// StringRef which refers to the SourceManager-owned buffer of the source
468  /// where that macro name is spelled. Thus, the result shouldn't out-live
469  /// that SourceManager.
470  ///
471  /// This differs from Lexer::getImmediateMacroName in that any macro argument
472  /// location will result in the topmost function macro that accepted it.
473  /// e.g.
474  /// \code
475  /// MAC1( MAC2(foo) )
476  /// \endcode
477  /// for location of 'foo' token, this function will return "MAC1" while
478  /// Lexer::getImmediateMacroName will return "MAC2".
479  static StringRef getImmediateMacroNameForDiagnostics(
480  SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts);
481 
482  /// Compute the preamble of the given file.
483  ///
484  /// The preamble of a file contains the initial comments, include directives,
485  /// and other preprocessor directives that occur before the code in this
486  /// particular file actually begins. The preamble of the main source file is
487  /// a potential prefix header.
488  ///
489  /// \param Buffer The memory buffer containing the file's contents.
490  ///
491  /// \param MaxLines If non-zero, restrict the length of the preamble
492  /// to fewer than this number of lines.
493  ///
494  /// \returns The offset into the file where the preamble ends and the rest
495  /// of the file begins along with a boolean value indicating whether
496  /// the preamble ends at the beginning of a new line.
497  static PreambleBounds ComputePreamble(StringRef Buffer,
498  const LangOptions &LangOpts,
499  unsigned MaxLines = 0);
500 
501  /// Finds the token that comes right after the given location.
502  ///
503  /// Returns the next token, or none if the location is inside a macro.
504  static Optional<Token> findNextToken(SourceLocation Loc,
505  const SourceManager &SM,
506  const LangOptions &LangOpts);
507 
508  /// Checks that the given token is the first token that occurs after
509  /// the given location (this excludes comments and whitespace). Returns the
510  /// location immediately after the specified token. If the token is not found
511  /// or the location is inside a macro, the returned source location will be
512  /// invalid.
513  static SourceLocation findLocationAfterToken(SourceLocation loc,
514  tok::TokenKind TKind,
515  const SourceManager &SM,
516  const LangOptions &LangOpts,
517  bool SkipTrailingWhitespaceAndNewLine);
518 
519  /// Returns true if the given character could appear in an identifier.
520  static bool isIdentifierBodyChar(char c, const LangOptions &LangOpts);
521 
522  /// Checks whether new line pointed by Str is preceded by escape
523  /// sequence.
524  static bool isNewLineEscaped(const char *BufferStart, const char *Str);
525 
526  /// getCharAndSizeNoWarn - Like the getCharAndSize method, but does not ever
527  /// emit a warning.
528  static inline char getCharAndSizeNoWarn(const char *Ptr, unsigned &Size,
529  const LangOptions &LangOpts) {
530  // If this is not a trigraph and not a UCN or escaped newline, return
531  // quickly.
532  if (isObviouslySimpleCharacter(Ptr[0])) {
533  Size = 1;
534  return *Ptr;
535  }
536 
537  Size = 0;
538  return getCharAndSizeSlowNoWarn(Ptr, Size, LangOpts);
539  }
540 
541  /// Returns the leading whitespace for line that corresponds to the given
542  /// location \p Loc.
543  static StringRef getIndentationForLine(SourceLocation Loc,
544  const SourceManager &SM);
545 
546 private:
547  //===--------------------------------------------------------------------===//
548  // Internal implementation interfaces.
549 
550  /// LexTokenInternal - Internal interface to lex a preprocessing token. Called
551  /// by Lex.
552  ///
553  bool LexTokenInternal(Token &Result, bool TokAtPhysicalStartOfLine);
554 
555  bool CheckUnicodeWhitespace(Token &Result, uint32_t C, const char *CurPtr);
556 
557  /// Given that a token begins with the Unicode character \p C, figure out
558  /// what kind of token it is and dispatch to the appropriate lexing helper
559  /// function.
560  bool LexUnicode(Token &Result, uint32_t C, const char *CurPtr);
561 
562  /// FormTokenWithChars - When we lex a token, we have identified a span
563  /// starting at BufferPtr, going to TokEnd that forms the token. This method
564  /// takes that range and assigns it to the token as its location and size. In
565  /// addition, since tokens cannot overlap, this also updates BufferPtr to be
566  /// TokEnd.
567  void FormTokenWithChars(Token &Result, const char *TokEnd,
569  unsigned TokLen = TokEnd-BufferPtr;
570  Result.setLength(TokLen);
571  Result.setLocation(getSourceLocation(BufferPtr, TokLen));
572  Result.setKind(Kind);
573  BufferPtr = TokEnd;
574  }
575 
576  /// isNextPPTokenLParen - Return 1 if the next unexpanded token will return a
577  /// tok::l_paren token, 0 if it is something else and 2 if there are no more
578  /// tokens in the buffer controlled by this lexer.
579  unsigned isNextPPTokenLParen();
580 
581  //===--------------------------------------------------------------------===//
582  // Lexer character reading interfaces.
583 
584  // This lexer is built on two interfaces for reading characters, both of which
585  // automatically provide phase 1/2 translation. getAndAdvanceChar is used
586  // when we know that we will be reading a character from the input buffer and
587  // that this character will be part of the result token. This occurs in (f.e.)
588  // string processing, because we know we need to read until we find the
589  // closing '"' character.
590  //
591  // The second interface is the combination of getCharAndSize with
592  // ConsumeChar. getCharAndSize reads a phase 1/2 translated character,
593  // returning it and its size. If the lexer decides that this character is
594  // part of the current token, it calls ConsumeChar on it. This two stage
595  // approach allows us to emit diagnostics for characters (e.g. warnings about
596  // trigraphs), knowing that they only are emitted if the character is
597  // consumed.
598 
599  /// isObviouslySimpleCharacter - Return true if the specified character is
600  /// obviously the same in translation phase 1 and translation phase 3. This
601  /// can return false for characters that end up being the same, but it will
602  /// never return true for something that needs to be mapped.
603  static bool isObviouslySimpleCharacter(char C) {
604  return C != '?' && C != '\\';
605  }
606 
607  /// getAndAdvanceChar - Read a single 'character' from the specified buffer,
608  /// advance over it, and return it. This is tricky in several cases. Here we
609  /// just handle the trivial case and fall-back to the non-inlined
610  /// getCharAndSizeSlow method to handle the hard case.
611  inline char getAndAdvanceChar(const char *&Ptr, Token &Tok) {
612  // If this is not a trigraph and not a UCN or escaped newline, return
613  // quickly.
614  if (isObviouslySimpleCharacter(Ptr[0])) return *Ptr++;
615 
616  unsigned Size = 0;
617  char C = getCharAndSizeSlow(Ptr, Size, &Tok);
618  Ptr += Size;
619  return C;
620  }
621 
622  /// ConsumeChar - When a character (identified by getCharAndSize) is consumed
623  /// and added to a given token, check to see if there are diagnostics that
624  /// need to be emitted or flags that need to be set on the token. If so, do
625  /// it.
626  const char *ConsumeChar(const char *Ptr, unsigned Size, Token &Tok) {
627  // Normal case, we consumed exactly one token. Just return it.
628  if (Size == 1)
629  return Ptr+Size;
630 
631  // Otherwise, re-lex the character with a current token, allowing
632  // diagnostics to be emitted and flags to be set.
633  Size = 0;
634  getCharAndSizeSlow(Ptr, Size, &Tok);
635  return Ptr+Size;
636  }
637 
638  /// getCharAndSize - Peek a single 'character' from the specified buffer,
639  /// get its size, and return it. This is tricky in several cases. Here we
640  /// just handle the trivial case and fall-back to the non-inlined
641  /// getCharAndSizeSlow method to handle the hard case.
642  inline char getCharAndSize(const char *Ptr, unsigned &Size) {
643  // If this is not a trigraph and not a UCN or escaped newline, return
644  // quickly.
645  if (isObviouslySimpleCharacter(Ptr[0])) {
646  Size = 1;
647  return *Ptr;
648  }
649 
650  Size = 0;
651  return getCharAndSizeSlow(Ptr, Size);
652  }
653 
654  /// getCharAndSizeSlow - Handle the slow/uncommon case of the getCharAndSize
655  /// method.
656  char getCharAndSizeSlow(const char *Ptr, unsigned &Size,
657  Token *Tok = nullptr);
658 
659  /// getEscapedNewLineSize - Return the size of the specified escaped newline,
660  /// or 0 if it is not an escaped newline. P[-1] is known to be a "\" on entry
661  /// to this function.
662  static unsigned getEscapedNewLineSize(const char *P);
663 
664  /// SkipEscapedNewLines - If P points to an escaped newline (or a series of
665  /// them), skip over them and return the first non-escaped-newline found,
666  /// otherwise return P.
667  static const char *SkipEscapedNewLines(const char *P);
668 
669  /// getCharAndSizeSlowNoWarn - Same as getCharAndSizeSlow, but never emits a
670  /// diagnostic.
671  static char getCharAndSizeSlowNoWarn(const char *Ptr, unsigned &Size,
672  const LangOptions &LangOpts);
673 
674  //===--------------------------------------------------------------------===//
675  // Other lexer functions.
676 
677  void SetByteOffset(unsigned Offset, bool StartOfLine);
678 
679  void PropagateLineStartLeadingSpaceInfo(Token &Result);
680 
681  const char *LexUDSuffix(Token &Result, const char *CurPtr,
682  bool IsStringLiteral);
683 
684  // Helper functions to lex the remainder of a token of the specific type.
685  bool LexIdentifier (Token &Result, const char *CurPtr);
686  bool LexNumericConstant (Token &Result, const char *CurPtr);
687  bool LexStringLiteral (Token &Result, const char *CurPtr,
688  tok::TokenKind Kind);
689  bool LexRawStringLiteral (Token &Result, const char *CurPtr,
690  tok::TokenKind Kind);
691  bool LexAngledStringLiteral(Token &Result, const char *CurPtr);
692  bool LexCharConstant (Token &Result, const char *CurPtr,
693  tok::TokenKind Kind);
694  bool LexEndOfFile (Token &Result, const char *CurPtr);
695  bool SkipWhitespace (Token &Result, const char *CurPtr,
696  bool &TokAtPhysicalStartOfLine);
697  bool SkipLineComment (Token &Result, const char *CurPtr,
698  bool &TokAtPhysicalStartOfLine);
699  bool SkipBlockComment (Token &Result, const char *CurPtr,
700  bool &TokAtPhysicalStartOfLine);
701  bool SaveLineComment (Token &Result, const char *CurPtr);
702 
703  bool IsStartOfConflictMarker(const char *CurPtr);
704  bool HandleEndOfConflictMarker(const char *CurPtr);
705 
706  bool lexEditorPlaceholder(Token &Result, const char *CurPtr);
707 
708  bool isCodeCompletionPoint(const char *CurPtr) const;
709  void cutOffLexing() { BufferPtr = BufferEnd; }
710 
711  bool isHexaLiteral(const char *Start, const LangOptions &LangOpts);
712 
713  void codeCompleteIncludedFile(const char *PathStart,
714  const char *CompletionPoint, bool IsAngled);
715 
716  /// Read a universal character name.
717  ///
718  /// \param StartPtr The position in the source buffer after the initial '\'.
719  /// If the UCN is syntactically well-formed (but not
720  /// necessarily valid), this parameter will be updated to
721  /// point to the character after the UCN.
722  /// \param SlashLoc The position in the source buffer of the '\'.
723  /// \param Result The token being formed. Pass \c nullptr to suppress
724  /// diagnostics and handle token formation in the caller.
725  ///
726  /// \return The Unicode codepoint specified by the UCN, or 0 if the UCN is
727  /// invalid.
728  uint32_t tryReadUCN(const char *&StartPtr, const char *SlashLoc, Token *Result);
729 
730  /// Try to consume a UCN as part of an identifier at the current
731  /// location.
732  /// \param CurPtr Initially points to the range of characters in the source
733  /// buffer containing the '\'. Updated to point past the end of
734  /// the UCN on success.
735  /// \param Size The number of characters occupied by the '\' (including
736  /// trigraphs and escaped newlines).
737  /// \param Result The token being produced. Marked as containing a UCN on
738  /// success.
739  /// \return \c true if a UCN was lexed and it produced an acceptable
740  /// identifier character, \c false otherwise.
741  bool tryConsumeIdentifierUCN(const char *&CurPtr, unsigned Size,
742  Token &Result);
743 
744  /// Try to consume an identifier character encoded in UTF-8.
745  /// \param CurPtr Points to the start of the (potential) UTF-8 code unit
746  /// sequence. On success, updated to point past the end of it.
747  /// \return \c true if a UTF-8 sequence mapping to an acceptable identifier
748  /// character was lexed, \c false otherwise.
749  bool tryConsumeIdentifierUTF8Char(const char *&CurPtr);
750 };
751 
752 } // namespace clang
753 
754 #endif // LLVM_CLANG_LEX_LEXER_H
Describes the bounds (start, size) of the preamble and a flag required by PreprocessorOptions::Precom...
Definition: Lexer.h:58
static DiagnosticBuilder Diag(DiagnosticsEngine *Diags, const LangOptions &Features, FullSourceLoc TokLoc, const char *TokBegin, const char *TokRangeBegin, const char *TokRangeEnd, unsigned DiagID)
Produce a diagnostic highlighting some portion of a literal.
Lexer - This provides a simple interface that turns a text buffer into a stream of tokens...
Definition: Lexer.h:76
SourceLocation getLocWithOffset(int Offset) const
Return a source location with the specified offset from this SourceLocation.
const char * getBufferLocation() const
Return the current location in the buffer.
Definition: Lexer.h:266
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:29
bool LexFromRawLexer(Token &Result)
LexFromRawLexer - Lex a token from a designated raw lexer (one with no associated preprocessor object...
Definition: Lexer.h:194
StringRef P
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:528
ConflictMarkerKind
ConflictMarkerKind - Kinds of conflict marker which the lexer might be recovering from...
Definition: Lexer.h:42
static CharSourceRange getAsCharRange(CharSourceRange Range, const SourceManager &SM, const LangOptions &LangOpts)
Definition: Lexer.h:387
Token - This structure provides full information about a lexed token.
Definition: Token.h:34
void setKind(tok::TokenKind K)
Definition: Token.h:90
SourceLocation getFileLoc() const
getFileLoc - Return the File Location for the file we are lexing out of.
Definition: Lexer.h:174
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
bool isPragmaLexer() const
isPragmaLexer - Returns true if this Lexer is being used to lex a pragma.
Definition: Lexer.h:183
A Perforce-style conflict marker, initiated by 4 ">"s, separated by 4 "="s, and terminated by 4 "<"s...
Definition: Lexer.h:52
SourceLocation getSourceLocation() override
getSourceLocation - Return a source location for the next character in the current file...
Definition: Lexer.h:261
const FormatToken & Tok
StringRef getBuffer() const
Gets source code buffer.
Definition: Lexer.h:242
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:348
bool PreambleEndsAtStartOfLine
Whether the preamble ends at the start of a new line.
Definition: Lexer.h:66
A little helper class used to produce diagnostics.
Definition: Diagnostic.h:1044
const LangOptions & getLangOpts() const
getLangOpts - Return the language features currently enabled.
Definition: Lexer.h:168
unsigned Offset
Definition: Format.cpp:1709
Defines the clang::LangOptions interface.
SourceLocation End
Represents a character-granular source range.
bool isKeepWhitespaceMode() const
isKeepWhitespaceMode - Return true if the lexer should return tokens for every character in the file...
Definition: Lexer.h:206
SourceLocation getEnd() const
const SourceManager & SM
Definition: Format.cpp:1568
Kind
Encodes a location in the source.
void setLength(unsigned Len)
Definition: Token.h:132
PreambleBounds(unsigned Size, bool PreambleEndsAtStartOfLine)
Definition: Lexer.h:68
TokenKind
Provides a simple uniform namespace for tokens from all C languages.
Definition: TokenKinds.h:24
bool inKeepCommentMode() const
inKeepCommentMode - Return true if the lexer should return comments as tokens.
Definition: Lexer.h:220
bool isTokenRange() const
Return true if the end of this range specifies the start of the last token.
An opaque identifier used by SourceManager which refers to a source file (MemoryBuffer) along with it...
SourceRange getAsRange() const
Dataflow Directional Tag Classes.
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:379
unsigned Size
Size of the preamble in bytes.
Definition: Lexer.h:60
Defines the clang::TokenKind enum and support functions.
Defines the clang::SourceLocation class and associated facilities.
Not within a conflict marker.
Definition: Lexer.h:44
void SetCommentRetentionState(bool Mode)
SetCommentRetentionMode - Change the comment retention mode of the lexer to the specified mode...
Definition: Lexer.h:227
void setLocation(SourceLocation L)
Definition: Token.h:131
A normal or diff3 conflict marker, initiated by at least 7 "<"s, separated by at least 7 "="s or "|"s...
Definition: Lexer.h:48
A trivial tuple used to represent a source range.
Defines the PreprocessorLexer interface.
void SetKeepWhitespaceMode(bool Val)
SetKeepWhitespaceMode - This method lets clients enable or disable whitespace retention mode...
Definition: Lexer.h:212
SourceLocation getBegin() const
This class handles loading and caching of source files into memory.
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:123