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1 //===--- Lexer.h - C Language Family Lexer ----------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file defines the Lexer interface.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_LEX_LEXER_H
15 #define LLVM_CLANG_LEX_LEXER_H
16 
17 #include "clang/Basic/LangOptions.h"
18 #include "clang/Lex/PreprocessorLexer.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include <cassert>
21 #include <string>
22 
23 namespace clang {
24 class DiagnosticsEngine;
25 class SourceManager;
26 class Preprocessor;
27 class DiagnosticBuilder;
28 
29 /// ConflictMarkerKind - Kinds of conflict marker which the lexer might be
30 /// recovering from.
31 enum ConflictMarkerKind {
32   /// Not within a conflict marker.
33   CMK_None,
34   /// A normal or diff3 conflict marker, initiated by at least 7 "<"s,
35   /// separated by at least 7 "="s or "|"s, and terminated by at least 7 ">"s.
36   CMK_Normal,
37   /// A Perforce-style conflict marker, initiated by 4 ">"s,
38   /// separated by 4 "="s, and terminated by 4 "<"s.
39   CMK_Perforce
40 };
41 
42 /// Lexer - This provides a simple interface that turns a text buffer into a
43 /// stream of tokens.  This provides no support for file reading or buffering,
44 /// or buffering/seeking of tokens, only forward lexing is supported.  It relies
45 /// on the specified Preprocessor object to handle preprocessor directives, etc.
46 class Lexer : public PreprocessorLexer {
47   void anchor() override;
48 
49   //===--------------------------------------------------------------------===//
50   // Constant configuration values for this lexer.
51   const char *BufferStart;       // Start of the buffer.
52   const char *BufferEnd;         // End of the buffer.
53   SourceLocation FileLoc;        // Location for start of file.
54   LangOptions LangOpts;          // LangOpts enabled by this language (cache).
55   bool Is_PragmaLexer;           // True if lexer for _Pragma handling.
56 
57   //===--------------------------------------------------------------------===//
58   // Context-specific lexing flags set by the preprocessor.
59   //
60 
61   /// ExtendedTokenMode - The lexer can optionally keep comments and whitespace
62   /// and return them as tokens.  This is used for -C and -CC modes, and
63   /// whitespace preservation can be useful for some clients that want to lex
64   /// the file in raw mode and get every character from the file.
65   ///
66   /// When this is set to 2 it returns comments and whitespace.  When set to 1
67   /// it returns comments, when it is set to 0 it returns normal tokens only.
68   unsigned char ExtendedTokenMode;
69 
70   //===--------------------------------------------------------------------===//
71   // Context that changes as the file is lexed.
72   // NOTE: any state that mutates when in raw mode must have save/restore code
73   // in Lexer::isNextPPTokenLParen.
74 
75   // BufferPtr - Current pointer into the buffer.  This is the next character
76   // to be lexed.
77   const char *BufferPtr;
78 
79   // IsAtStartOfLine - True if the next lexed token should get the "start of
80   // line" flag set on it.
81   bool IsAtStartOfLine;
82 
83   bool IsAtPhysicalStartOfLine;
84 
85   bool HasLeadingSpace;
86 
87   bool HasLeadingEmptyMacro;
88 
89   // CurrentConflictMarkerState - The kind of conflict marker we are handling.
90   ConflictMarkerKind CurrentConflictMarkerState;
91 
92   Lexer(const Lexer &) = delete;
93   void operator=(const Lexer &) = delete;
94   friend class Preprocessor;
95 
96   void InitLexer(const char *BufStart, const char *BufPtr, const char *BufEnd);
97 public:
98 
99   /// Lexer constructor - Create a new lexer object for the specified buffer
100   /// with the specified preprocessor managing the lexing process.  This lexer
101   /// assumes that the associated file buffer and Preprocessor objects will
102   /// outlive it, so it doesn't take ownership of either of them.
103   Lexer(FileID FID, const llvm::MemoryBuffer *InputBuffer, Preprocessor &PP);
104 
105   /// Lexer constructor - Create a new raw lexer object.  This object is only
106   /// suitable for calls to 'LexFromRawLexer'.  This lexer assumes that the
107   /// text range will outlive it, so it doesn't take ownership of it.
108   Lexer(SourceLocation FileLoc, const LangOptions &LangOpts,
109         const char *BufStart, const char *BufPtr, const char *BufEnd);
110 
111   /// Lexer constructor - Create a new raw lexer object.  This object is only
112   /// suitable for calls to 'LexFromRawLexer'.  This lexer assumes that the
113   /// text range will outlive it, so it doesn't take ownership of it.
114   Lexer(FileID FID, const llvm::MemoryBuffer *InputBuffer,
115         const SourceManager &SM, const LangOptions &LangOpts);
116 
117   /// Create_PragmaLexer: Lexer constructor - Create a new lexer object for
118   /// _Pragma expansion.  This has a variety of magic semantics that this method
119   /// sets up.  It returns a new'd Lexer that must be delete'd when done.
120   static Lexer *Create_PragmaLexer(SourceLocation SpellingLoc,
121                                    SourceLocation ExpansionLocStart,
122                                    SourceLocation ExpansionLocEnd,
123                                    unsigned TokLen, Preprocessor &PP);
124 
125 
126   /// getLangOpts - Return the language features currently enabled.
127   /// NOTE: this lexer modifies features as a file is parsed!
getLangOpts()128   const LangOptions &getLangOpts() const { return LangOpts; }
129 
130   /// getFileLoc - Return the File Location for the file we are lexing out of.
131   /// The physical location encodes the location where the characters come from,
132   /// the virtual location encodes where we should *claim* the characters came
133   /// from.  Currently this is only used by _Pragma handling.
getFileLoc()134   SourceLocation getFileLoc() const { return FileLoc; }
135 
136 private:
137   /// Lex - Return the next token in the file.  If this is the end of file, it
138   /// return the tok::eof token.  This implicitly involves the preprocessor.
139   bool Lex(Token &Result);
140 
141 public:
142   /// isPragmaLexer - Returns true if this Lexer is being used to lex a pragma.
isPragmaLexer()143   bool isPragmaLexer() const { return Is_PragmaLexer; }
144 
145 private:
146   /// IndirectLex - An indirect call to 'Lex' that can be invoked via
147   ///  the PreprocessorLexer interface.
IndirectLex(Token & Result)148   void IndirectLex(Token &Result) override { Lex(Result); }
149 
150 public:
151   /// LexFromRawLexer - Lex a token from a designated raw lexer (one with no
152   /// associated preprocessor object.  Return true if the 'next character to
153   /// read' pointer points at the end of the lexer buffer, false otherwise.
LexFromRawLexer(Token & Result)154   bool LexFromRawLexer(Token &Result) {
155     assert(LexingRawMode && "Not already in raw mode!");
156     Lex(Result);
157     // Note that lexing to the end of the buffer doesn't implicitly delete the
158     // lexer when in raw mode.
159     return BufferPtr == BufferEnd;
160   }
161 
162   /// isKeepWhitespaceMode - Return true if the lexer should return tokens for
163   /// every character in the file, including whitespace and comments.  This
164   /// should only be used in raw mode, as the preprocessor is not prepared to
165   /// deal with the excess tokens.
isKeepWhitespaceMode()166   bool isKeepWhitespaceMode() const {
167     return ExtendedTokenMode > 1;
168   }
169 
170   /// SetKeepWhitespaceMode - This method lets clients enable or disable
171   /// whitespace retention mode.
SetKeepWhitespaceMode(bool Val)172   void SetKeepWhitespaceMode(bool Val) {
173     assert((!Val || LexingRawMode || LangOpts.TraditionalCPP) &&
174            "Can only retain whitespace in raw mode or -traditional-cpp");
175     ExtendedTokenMode = Val ? 2 : 0;
176   }
177 
178   /// inKeepCommentMode - Return true if the lexer should return comments as
179   /// tokens.
inKeepCommentMode()180   bool inKeepCommentMode() const {
181     return ExtendedTokenMode > 0;
182   }
183 
184   /// SetCommentRetentionMode - Change the comment retention mode of the lexer
185   /// to the specified mode.  This is really only useful when lexing in raw
186   /// mode, because otherwise the lexer needs to manage this.
SetCommentRetentionState(bool Mode)187   void SetCommentRetentionState(bool Mode) {
188     assert(!isKeepWhitespaceMode() &&
189            "Can't play with comment retention state when retaining whitespace");
190     ExtendedTokenMode = Mode ? 1 : 0;
191   }
192 
193   /// Sets the extended token mode back to its initial value, according to the
194   /// language options and preprocessor. This controls whether the lexer
195   /// produces comment and whitespace tokens.
196   ///
197   /// This requires the lexer to have an associated preprocessor. A standalone
198   /// lexer has nothing to reset to.
199   void resetExtendedTokenMode();
200 
201   /// Gets source code buffer.
getBuffer()202   StringRef getBuffer() const {
203     return StringRef(BufferStart, BufferEnd - BufferStart);
204   }
205 
206   /// ReadToEndOfLine - Read the rest of the current preprocessor line as an
207   /// uninterpreted string.  This switches the lexer out of directive mode.
208   void ReadToEndOfLine(SmallVectorImpl<char> *Result = nullptr);
209 
210 
211   /// Diag - Forwarding function for diagnostics.  This translate a source
212   /// position in the current buffer into a SourceLocation object for rendering.
213   DiagnosticBuilder Diag(const char *Loc, unsigned DiagID) const;
214 
215   /// getSourceLocation - Return a source location identifier for the specified
216   /// offset in the current file.
217   SourceLocation getSourceLocation(const char *Loc, unsigned TokLen = 1) const;
218 
219   /// getSourceLocation - Return a source location for the next character in
220   /// the current file.
getSourceLocation()221   SourceLocation getSourceLocation() override {
222     return getSourceLocation(BufferPtr);
223   }
224 
225   /// \brief Return the current location in the buffer.
getBufferLocation()226   const char *getBufferLocation() const { return BufferPtr; }
227 
228   /// Stringify - Convert the specified string into a C string by escaping '\'
229   /// and " characters.  This does not add surrounding ""'s to the string.
230   /// If Charify is true, this escapes the ' character instead of ".
231   static std::string Stringify(StringRef Str, bool Charify = false);
232 
233   /// Stringify - Convert the specified string into a C string by escaping '\'
234   /// and " characters.  This does not add surrounding ""'s to the string.
235   static void Stringify(SmallVectorImpl<char> &Str);
236 
237 
238   /// getSpelling - This method is used to get the spelling of a token into a
239   /// preallocated buffer, instead of as an std::string.  The caller is required
240   /// to allocate enough space for the token, which is guaranteed to be at least
241   /// Tok.getLength() bytes long.  The length of the actual result is returned.
242   ///
243   /// Note that this method may do two possible things: it may either fill in
244   /// the buffer specified with characters, or it may *change the input pointer*
245   /// to point to a constant buffer with the data already in it (avoiding a
246   /// copy).  The caller is not allowed to modify the returned buffer pointer
247   /// if an internal buffer is returned.
248   static unsigned getSpelling(const Token &Tok, const char *&Buffer,
249                               const SourceManager &SourceMgr,
250                               const LangOptions &LangOpts,
251                               bool *Invalid = nullptr);
252 
253   /// getSpelling() - Return the 'spelling' of the Tok token.  The spelling of a
254   /// token is the characters used to represent the token in the source file
255   /// after trigraph expansion and escaped-newline folding.  In particular, this
256   /// wants to get the true, uncanonicalized, spelling of things like digraphs
257   /// UCNs, etc.
258   static std::string getSpelling(const Token &Tok,
259                                  const SourceManager &SourceMgr,
260                                  const LangOptions &LangOpts,
261                                  bool *Invalid = nullptr);
262 
263   /// getSpelling - This method is used to get the spelling of the
264   /// token at the given source location.  If, as is usually true, it
265   /// is not necessary to copy any data, then the returned string may
266   /// not point into the provided buffer.
267   ///
268   /// This method lexes at the expansion depth of the given
269   /// location and does not jump to the expansion or spelling
270   /// location.
271   static StringRef getSpelling(SourceLocation loc,
272                                SmallVectorImpl<char> &buffer,
273                                const SourceManager &SourceMgr,
274                                const LangOptions &LangOpts,
275                                bool *invalid = nullptr);
276 
277   /// MeasureTokenLength - Relex the token at the specified location and return
278   /// its length in bytes in the input file.  If the token needs cleaning (e.g.
279   /// includes a trigraph or an escaped newline) then this count includes bytes
280   /// that are part of that.
281   static unsigned MeasureTokenLength(SourceLocation Loc,
282                                      const SourceManager &SM,
283                                      const LangOptions &LangOpts);
284 
285   /// \brief Relex the token at the specified location.
286   /// \returns true if there was a failure, false on success.
287   static bool getRawToken(SourceLocation Loc, Token &Result,
288                           const SourceManager &SM,
289                           const LangOptions &LangOpts,
290                           bool IgnoreWhiteSpace = false);
291 
292   /// \brief Given a location any where in a source buffer, find the location
293   /// that corresponds to the beginning of the token in which the original
294   /// source location lands.
295   static SourceLocation GetBeginningOfToken(SourceLocation Loc,
296                                             const SourceManager &SM,
297                                             const LangOptions &LangOpts);
298 
299   /// AdvanceToTokenCharacter - If the current SourceLocation specifies a
300   /// location at the start of a token, return a new location that specifies a
301   /// character within the token.  This handles trigraphs and escaped newlines.
302   static SourceLocation AdvanceToTokenCharacter(SourceLocation TokStart,
303                                                 unsigned Character,
304                                                 const SourceManager &SM,
305                                                 const LangOptions &LangOpts);
306 
307   /// \brief Computes the source location just past the end of the
308   /// token at this source location.
309   ///
310   /// This routine can be used to produce a source location that
311   /// points just past the end of the token referenced by \p Loc, and
312   /// is generally used when a diagnostic needs to point just after a
313   /// token where it expected something different that it received. If
314   /// the returned source location would not be meaningful (e.g., if
315   /// it points into a macro), this routine returns an invalid
316   /// source location.
317   ///
318   /// \param Offset an offset from the end of the token, where the source
319   /// location should refer to. The default offset (0) produces a source
320   /// location pointing just past the end of the token; an offset of 1 produces
321   /// a source location pointing to the last character in the token, etc.
322   static SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset,
323                                             const SourceManager &SM,
324                                             const LangOptions &LangOpts);
325 
326   /// \brief Given a token range, produce a corresponding CharSourceRange that
327   /// is not a token range. This allows the source range to be used by
328   /// components that don't have access to the lexer and thus can't find the
329   /// end of the range for themselves.
getAsCharRange(SourceRange Range,const SourceManager & SM,const LangOptions & LangOpts)330   static CharSourceRange getAsCharRange(SourceRange Range,
331                                         const SourceManager &SM,
332                                         const LangOptions &LangOpts) {
333     SourceLocation End = getLocForEndOfToken(Range.getEnd(), 0, SM, LangOpts);
334     return End.isInvalid() ? CharSourceRange()
335                            : CharSourceRange::getCharRange(
336                                  Range.getBegin(), End.getLocWithOffset(-1));
337   }
getAsCharRange(CharSourceRange Range,const SourceManager & SM,const LangOptions & LangOpts)338   static CharSourceRange getAsCharRange(CharSourceRange Range,
339                                         const SourceManager &SM,
340                                         const LangOptions &LangOpts) {
341     return Range.isTokenRange()
342                ? getAsCharRange(Range.getAsRange(), SM, LangOpts)
343                : Range;
344   }
345 
346   /// \brief Returns true if the given MacroID location points at the first
347   /// token of the macro expansion.
348   ///
349   /// \param MacroBegin If non-null and function returns true, it is set to
350   /// begin location of the macro.
351   static bool isAtStartOfMacroExpansion(SourceLocation loc,
352                                         const SourceManager &SM,
353                                         const LangOptions &LangOpts,
354                                         SourceLocation *MacroBegin = nullptr);
355 
356   /// \brief Returns true if the given MacroID location points at the last
357   /// token of the macro expansion.
358   ///
359   /// \param MacroEnd If non-null and function returns true, it is set to
360   /// end location of the macro.
361   static bool isAtEndOfMacroExpansion(SourceLocation loc,
362                                       const SourceManager &SM,
363                                       const LangOptions &LangOpts,
364                                       SourceLocation *MacroEnd = nullptr);
365 
366   /// \brief Accepts a range and returns a character range with file locations.
367   ///
368   /// Returns a null range if a part of the range resides inside a macro
369   /// expansion or the range does not reside on the same FileID.
370   ///
371   /// This function is trying to deal with macros and return a range based on
372   /// file locations. The cases where it can successfully handle macros are:
373   ///
374   /// -begin or end range lies at the start or end of a macro expansion, in
375   ///  which case the location will be set to the expansion point, e.g:
376   ///    \#define M 1 2
377   ///    a M
378   /// If you have a range [a, 2] (where 2 came from the macro), the function
379   /// will return a range for "a M"
380   /// if you have range [a, 1], the function will fail because the range
381   /// overlaps with only a part of the macro
382   ///
383   /// -The macro is a function macro and the range can be mapped to the macro
384   ///  arguments, e.g:
385   ///    \#define M 1 2
386   ///    \#define FM(x) x
387   ///    FM(a b M)
388   /// if you have range [b, 2], the function will return the file range "b M"
389   /// inside the macro arguments.
390   /// if you have range [a, 2], the function will return the file range
391   /// "FM(a b M)" since the range includes all of the macro expansion.
392   static CharSourceRange makeFileCharRange(CharSourceRange Range,
393                                            const SourceManager &SM,
394                                            const LangOptions &LangOpts);
395 
396   /// \brief Returns a string for the source that the range encompasses.
397   static StringRef getSourceText(CharSourceRange Range,
398                                  const SourceManager &SM,
399                                  const LangOptions &LangOpts,
400                                  bool *Invalid = nullptr);
401 
402   /// \brief Retrieve the name of the immediate macro expansion.
403   ///
404   /// This routine starts from a source location, and finds the name of the macro
405   /// responsible for its immediate expansion. It looks through any intervening
406   /// macro argument expansions to compute this. It returns a StringRef which
407   /// refers to the SourceManager-owned buffer of the source where that macro
408   /// name is spelled. Thus, the result shouldn't out-live that SourceManager.
409   static StringRef getImmediateMacroName(SourceLocation Loc,
410                                          const SourceManager &SM,
411                                          const LangOptions &LangOpts);
412 
413   /// \brief Retrieve the name of the immediate macro expansion.
414   ///
415   /// This routine starts from a source location, and finds the name of the
416   /// macro responsible for its immediate expansion. It looks through any
417   /// intervening macro argument expansions to compute this. It returns a
418   /// StringRef which refers to the SourceManager-owned buffer of the source
419   /// where that macro name is spelled. Thus, the result shouldn't out-live
420   /// that SourceManager.
421   ///
422   /// This differs from Lexer::getImmediateMacroName in that any macro argument
423   /// location will result in the topmost function macro that accepted it.
424   /// e.g.
425   /// \code
426   ///   MAC1( MAC2(foo) )
427   /// \endcode
428   /// for location of 'foo' token, this function will return "MAC1" while
429   /// Lexer::getImmediateMacroName will return "MAC2".
430   static StringRef getImmediateMacroNameForDiagnostics(
431       SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts);
432 
433   /// \brief Compute the preamble of the given file.
434   ///
435   /// The preamble of a file contains the initial comments, include directives,
436   /// and other preprocessor directives that occur before the code in this
437   /// particular file actually begins. The preamble of the main source file is
438   /// a potential prefix header.
439   ///
440   /// \param Buffer The memory buffer containing the file's contents.
441   ///
442   /// \param MaxLines If non-zero, restrict the length of the preamble
443   /// to fewer than this number of lines.
444   ///
445   /// \returns The offset into the file where the preamble ends and the rest
446   /// of the file begins along with a boolean value indicating whether
447   /// the preamble ends at the beginning of a new line.
448   static std::pair<unsigned, bool> ComputePreamble(StringRef Buffer,
449                                                    const LangOptions &LangOpts,
450                                                    unsigned MaxLines = 0);
451 
452   /// \brief Checks that the given token is the first token that occurs after
453   /// the given location (this excludes comments and whitespace). Returns the
454   /// location immediately after the specified token. If the token is not found
455   /// or the location is inside a macro, the returned source location will be
456   /// invalid.
457   static SourceLocation findLocationAfterToken(SourceLocation loc,
458                                          tok::TokenKind TKind,
459                                          const SourceManager &SM,
460                                          const LangOptions &LangOpts,
461                                          bool SkipTrailingWhitespaceAndNewLine);
462 
463   /// \brief Returns true if the given character could appear in an identifier.
464   static bool isIdentifierBodyChar(char c, const LangOptions &LangOpts);
465 
466   /// getCharAndSizeNoWarn - Like the getCharAndSize method, but does not ever
467   /// emit a warning.
getCharAndSizeNoWarn(const char * Ptr,unsigned & Size,const LangOptions & LangOpts)468   static inline char getCharAndSizeNoWarn(const char *Ptr, unsigned &Size,
469                                           const LangOptions &LangOpts) {
470     // If this is not a trigraph and not a UCN or escaped newline, return
471     // quickly.
472     if (isObviouslySimpleCharacter(Ptr[0])) {
473       Size = 1;
474       return *Ptr;
475     }
476 
477     Size = 0;
478     return getCharAndSizeSlowNoWarn(Ptr, Size, LangOpts);
479   }
480 
481   //===--------------------------------------------------------------------===//
482   // Internal implementation interfaces.
483 private:
484 
485   /// LexTokenInternal - Internal interface to lex a preprocessing token. Called
486   /// by Lex.
487   ///
488   bool LexTokenInternal(Token &Result, bool TokAtPhysicalStartOfLine);
489 
490   bool CheckUnicodeWhitespace(Token &Result, uint32_t C, const char *CurPtr);
491 
492   /// Given that a token begins with the Unicode character \p C, figure out
493   /// what kind of token it is and dispatch to the appropriate lexing helper
494   /// function.
495   bool LexUnicode(Token &Result, uint32_t C, const char *CurPtr);
496 
497   /// FormTokenWithChars - When we lex a token, we have identified a span
498   /// starting at BufferPtr, going to TokEnd that forms the token.  This method
499   /// takes that range and assigns it to the token as its location and size.  In
500   /// addition, since tokens cannot overlap, this also updates BufferPtr to be
501   /// TokEnd.
FormTokenWithChars(Token & Result,const char * TokEnd,tok::TokenKind Kind)502   void FormTokenWithChars(Token &Result, const char *TokEnd,
503                           tok::TokenKind Kind) {
504     unsigned TokLen = TokEnd-BufferPtr;
505     Result.setLength(TokLen);
506     Result.setLocation(getSourceLocation(BufferPtr, TokLen));
507     Result.setKind(Kind);
508     BufferPtr = TokEnd;
509   }
510 
511   /// isNextPPTokenLParen - Return 1 if the next unexpanded token will return a
512   /// tok::l_paren token, 0 if it is something else and 2 if there are no more
513   /// tokens in the buffer controlled by this lexer.
514   unsigned isNextPPTokenLParen();
515 
516   //===--------------------------------------------------------------------===//
517   // Lexer character reading interfaces.
518 
519   // This lexer is built on two interfaces for reading characters, both of which
520   // automatically provide phase 1/2 translation.  getAndAdvanceChar is used
521   // when we know that we will be reading a character from the input buffer and
522   // that this character will be part of the result token. This occurs in (f.e.)
523   // string processing, because we know we need to read until we find the
524   // closing '"' character.
525   //
526   // The second interface is the combination of getCharAndSize with
527   // ConsumeChar.  getCharAndSize reads a phase 1/2 translated character,
528   // returning it and its size.  If the lexer decides that this character is
529   // part of the current token, it calls ConsumeChar on it.  This two stage
530   // approach allows us to emit diagnostics for characters (e.g. warnings about
531   // trigraphs), knowing that they only are emitted if the character is
532   // consumed.
533 
534   /// isObviouslySimpleCharacter - Return true if the specified character is
535   /// obviously the same in translation phase 1 and translation phase 3.  This
536   /// can return false for characters that end up being the same, but it will
537   /// never return true for something that needs to be mapped.
isObviouslySimpleCharacter(char C)538   static bool isObviouslySimpleCharacter(char C) {
539     return C != '?' && C != '\\';
540   }
541 
542   /// getAndAdvanceChar - Read a single 'character' from the specified buffer,
543   /// advance over it, and return it.  This is tricky in several cases.  Here we
544   /// just handle the trivial case and fall-back to the non-inlined
545   /// getCharAndSizeSlow method to handle the hard case.
getAndAdvanceChar(const char * & Ptr,Token & Tok)546   inline char getAndAdvanceChar(const char *&Ptr, Token &Tok) {
547     // If this is not a trigraph and not a UCN or escaped newline, return
548     // quickly.
549     if (isObviouslySimpleCharacter(Ptr[0])) return *Ptr++;
550 
551     unsigned Size = 0;
552     char C = getCharAndSizeSlow(Ptr, Size, &Tok);
553     Ptr += Size;
554     return C;
555   }
556 
557   /// ConsumeChar - When a character (identified by getCharAndSize) is consumed
558   /// and added to a given token, check to see if there are diagnostics that
559   /// need to be emitted or flags that need to be set on the token.  If so, do
560   /// it.
ConsumeChar(const char * Ptr,unsigned Size,Token & Tok)561   const char *ConsumeChar(const char *Ptr, unsigned Size, Token &Tok) {
562     // Normal case, we consumed exactly one token.  Just return it.
563     if (Size == 1)
564       return Ptr+Size;
565 
566     // Otherwise, re-lex the character with a current token, allowing
567     // diagnostics to be emitted and flags to be set.
568     Size = 0;
569     getCharAndSizeSlow(Ptr, Size, &Tok);
570     return Ptr+Size;
571   }
572 
573   /// getCharAndSize - Peek a single 'character' from the specified buffer,
574   /// get its size, and return it.  This is tricky in several cases.  Here we
575   /// just handle the trivial case and fall-back to the non-inlined
576   /// getCharAndSizeSlow method to handle the hard case.
getCharAndSize(const char * Ptr,unsigned & Size)577   inline char getCharAndSize(const char *Ptr, unsigned &Size) {
578     // If this is not a trigraph and not a UCN or escaped newline, return
579     // quickly.
580     if (isObviouslySimpleCharacter(Ptr[0])) {
581       Size = 1;
582       return *Ptr;
583     }
584 
585     Size = 0;
586     return getCharAndSizeSlow(Ptr, Size);
587   }
588 
589   /// getCharAndSizeSlow - Handle the slow/uncommon case of the getCharAndSize
590   /// method.
591   char getCharAndSizeSlow(const char *Ptr, unsigned &Size,
592                           Token *Tok = nullptr);
593 
594   /// getEscapedNewLineSize - Return the size of the specified escaped newline,
595   /// or 0 if it is not an escaped newline. P[-1] is known to be a "\" on entry
596   /// to this function.
597   static unsigned getEscapedNewLineSize(const char *P);
598 
599   /// SkipEscapedNewLines - If P points to an escaped newline (or a series of
600   /// them), skip over them and return the first non-escaped-newline found,
601   /// otherwise return P.
602   static const char *SkipEscapedNewLines(const char *P);
603 
604   /// getCharAndSizeSlowNoWarn - Same as getCharAndSizeSlow, but never emits a
605   /// diagnostic.
606   static char getCharAndSizeSlowNoWarn(const char *Ptr, unsigned &Size,
607                                        const LangOptions &LangOpts);
608 
609   //===--------------------------------------------------------------------===//
610   // Other lexer functions.
611 
612   void SkipBytes(unsigned Bytes, bool StartOfLine);
613 
614   void PropagateLineStartLeadingSpaceInfo(Token &Result);
615 
616   const char *LexUDSuffix(Token &Result, const char *CurPtr,
617                           bool IsStringLiteral);
618 
619   // Helper functions to lex the remainder of a token of the specific type.
620   bool LexIdentifier         (Token &Result, const char *CurPtr);
621   bool LexNumericConstant    (Token &Result, const char *CurPtr);
622   bool LexStringLiteral      (Token &Result, const char *CurPtr,
623                               tok::TokenKind Kind);
624   bool LexRawStringLiteral   (Token &Result, const char *CurPtr,
625                               tok::TokenKind Kind);
626   bool LexAngledStringLiteral(Token &Result, const char *CurPtr);
627   bool LexCharConstant       (Token &Result, const char *CurPtr,
628                               tok::TokenKind Kind);
629   bool LexEndOfFile          (Token &Result, const char *CurPtr);
630   bool SkipWhitespace        (Token &Result, const char *CurPtr,
631                               bool &TokAtPhysicalStartOfLine);
632   bool SkipLineComment       (Token &Result, const char *CurPtr,
633                               bool &TokAtPhysicalStartOfLine);
634   bool SkipBlockComment      (Token &Result, const char *CurPtr,
635                               bool &TokAtPhysicalStartOfLine);
636   bool SaveLineComment       (Token &Result, const char *CurPtr);
637 
638   bool IsStartOfConflictMarker(const char *CurPtr);
639   bool HandleEndOfConflictMarker(const char *CurPtr);
640 
641   bool isCodeCompletionPoint(const char *CurPtr) const;
cutOffLexing()642   void cutOffLexing() { BufferPtr = BufferEnd; }
643 
644   bool isHexaLiteral(const char *Start, const LangOptions &LangOpts);
645 
646 
647   /// Read a universal character name.
648   ///
649   /// \param CurPtr The position in the source buffer after the initial '\'.
650   ///               If the UCN is syntactically well-formed (but not necessarily
651   ///               valid), this parameter will be updated to point to the
652   ///               character after the UCN.
653   /// \param SlashLoc The position in the source buffer of the '\'.
654   /// \param Tok The token being formed. Pass \c NULL to suppress diagnostics
655   ///            and handle token formation in the caller.
656   ///
657   /// \return The Unicode codepoint specified by the UCN, or 0 if the UCN is
658   ///         invalid.
659   uint32_t tryReadUCN(const char *&CurPtr, const char *SlashLoc, Token *Tok);
660 
661   /// \brief Try to consume a UCN as part of an identifier at the current
662   /// location.
663   /// \param CurPtr Initially points to the range of characters in the source
664   ///               buffer containing the '\'. Updated to point past the end of
665   ///               the UCN on success.
666   /// \param Size The number of characters occupied by the '\' (including
667   ///             trigraphs and escaped newlines).
668   /// \param Result The token being produced. Marked as containing a UCN on
669   ///               success.
670   /// \return \c true if a UCN was lexed and it produced an acceptable
671   ///         identifier character, \c false otherwise.
672   bool tryConsumeIdentifierUCN(const char *&CurPtr, unsigned Size,
673                                Token &Result);
674 
675   /// \brief Try to consume an identifier character encoded in UTF-8.
676   /// \param CurPtr Points to the start of the (potential) UTF-8 code unit
677   ///        sequence. On success, updated to point past the end of it.
678   /// \return \c true if a UTF-8 sequence mapping to an acceptable identifier
679   ///         character was lexed, \c false otherwise.
680   bool tryConsumeIdentifierUTF8Char(const char *&CurPtr);
681 };
682 
683 }  // end namespace clang
684 
685 #endif
686