1 //===--- Lexer.h - C Language Family Lexer ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the Lexer interface.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_LEXER_H
15 #define LLVM_CLANG_LEXER_H
17 #include "clang/Lex/PreprocessorLexer.h"
18 #include "clang/Basic/LangOptions.h"
19 #include "llvm/ADT/SmallVector.h"
24 class DiagnosticsEngine;
27 class DiagnosticBuilder;
29 /// ConflictMarkerKind - Kinds of conflict marker which the lexer might be
31 enum ConflictMarkerKind {
32 /// Not within a conflict marker.
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.
37 /// A Perforce-style conflict marker, initiated by 4 >s, separated by 4 =s,
38 /// and terminated by 4 <s.
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 virtual void anchor();
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.
57 //===--------------------------------------------------------------------===//
58 // Context-specific lexing flags set by the preprocessor.
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.
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;
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.
75 // BufferPtr - Current pointer into the buffer. This is the next character
77 const char *BufferPtr;
79 // IsAtStartOfLine - True if the next lexed token should get the "start of
80 // line" flag set on it.
83 // CurrentConflictMarkerState - The kind of conflict marker we are handling.
84 ConflictMarkerKind CurrentConflictMarkerState;
86 Lexer(const Lexer&); // DO NOT IMPLEMENT
87 void operator=(const Lexer&); // DO NOT IMPLEMENT
88 friend class Preprocessor;
90 void InitLexer(const char *BufStart, const char *BufPtr, const char *BufEnd);
93 /// Lexer constructor - Create a new lexer object for the specified buffer
94 /// with the specified preprocessor managing the lexing process. This lexer
95 /// assumes that the associated file buffer and Preprocessor objects will
96 /// outlive it, so it doesn't take ownership of either of them.
97 Lexer(FileID FID, const llvm::MemoryBuffer *InputBuffer, Preprocessor &PP);
99 /// Lexer constructor - Create a new raw lexer object. This object is only
100 /// suitable for calls to 'LexRawToken'. This lexer assumes that the text
101 /// range will outlive it, so it doesn't take ownership of it.
102 Lexer(SourceLocation FileLoc, const LangOptions &LangOpts,
103 const char *BufStart, const char *BufPtr, const char *BufEnd);
105 /// Lexer constructor - Create a new raw lexer object. This object is only
106 /// suitable for calls to 'LexRawToken'. This lexer assumes that the text
107 /// range will outlive it, so it doesn't take ownership of it.
108 Lexer(FileID FID, const llvm::MemoryBuffer *InputBuffer,
109 const SourceManager &SM, const LangOptions &LangOpts);
111 /// Create_PragmaLexer: Lexer constructor - Create a new lexer object for
112 /// _Pragma expansion. This has a variety of magic semantics that this method
113 /// sets up. It returns a new'd Lexer that must be delete'd when done.
114 static Lexer *Create_PragmaLexer(SourceLocation SpellingLoc,
115 SourceLocation ExpansionLocStart,
116 SourceLocation ExpansionLocEnd,
117 unsigned TokLen, Preprocessor &PP);
120 /// getLangOpts - Return the language features currently enabled.
121 /// NOTE: this lexer modifies features as a file is parsed!
122 const LangOptions &getLangOpts() const { return LangOpts; }
124 /// getFileLoc - Return the File Location for the file we are lexing out of.
125 /// The physical location encodes the location where the characters come from,
126 /// the virtual location encodes where we should *claim* the characters came
127 /// from. Currently this is only used by _Pragma handling.
128 SourceLocation getFileLoc() const { return FileLoc; }
130 /// Lex - Return the next token in the file. If this is the end of file, it
131 /// return the tok::eof token. Return true if an error occurred and
132 /// compilation should terminate, false if normal. This implicitly involves
133 /// the preprocessor.
134 void Lex(Token &Result) {
135 // Start a new token.
138 // NOTE, any changes here should also change code after calls to
139 // Preprocessor::HandleDirective
140 if (IsAtStartOfLine) {
141 Result.setFlag(Token::StartOfLine);
142 IsAtStartOfLine = false;
145 // Get a token. Note that this may delete the current lexer if the end of
147 LexTokenInternal(Result);
150 /// isPragmaLexer - Returns true if this Lexer is being used to lex a pragma.
151 bool isPragmaLexer() const { return Is_PragmaLexer; }
153 /// IndirectLex - An indirect call to 'Lex' that can be invoked via
154 /// the PreprocessorLexer interface.
155 void IndirectLex(Token &Result) { Lex(Result); }
157 /// LexFromRawLexer - Lex a token from a designated raw lexer (one with no
158 /// associated preprocessor object. Return true if the 'next character to
159 /// read' pointer points at the end of the lexer buffer, false otherwise.
160 bool LexFromRawLexer(Token &Result) {
161 assert(LexingRawMode && "Not already in raw mode!");
163 // Note that lexing to the end of the buffer doesn't implicitly delete the
164 // lexer when in raw mode.
165 return BufferPtr == BufferEnd;
168 /// isKeepWhitespaceMode - Return true if the lexer should return tokens for
169 /// every character in the file, including whitespace and comments. This
170 /// should only be used in raw mode, as the preprocessor is not prepared to
171 /// deal with the excess tokens.
172 bool isKeepWhitespaceMode() const {
173 return ExtendedTokenMode > 1;
176 /// SetKeepWhitespaceMode - This method lets clients enable or disable
177 /// whitespace retention mode.
178 void SetKeepWhitespaceMode(bool Val) {
179 assert((!Val || LexingRawMode) &&
180 "Can only enable whitespace retention in raw mode");
181 ExtendedTokenMode = Val ? 2 : 0;
184 /// inKeepCommentMode - Return true if the lexer should return comments as
186 bool inKeepCommentMode() const {
187 return ExtendedTokenMode > 0;
190 /// SetCommentRetentionMode - Change the comment retention mode of the lexer
191 /// to the specified mode. This is really only useful when lexing in raw
192 /// mode, because otherwise the lexer needs to manage this.
193 void SetCommentRetentionState(bool Mode) {
194 assert(!isKeepWhitespaceMode() &&
195 "Can't play with comment retention state when retaining whitespace");
196 ExtendedTokenMode = Mode ? 1 : 0;
199 const char *getBufferStart() const { return BufferStart; }
201 /// ReadToEndOfLine - Read the rest of the current preprocessor line as an
202 /// uninterpreted string. This switches the lexer out of directive mode.
203 std::string ReadToEndOfLine();
206 /// Diag - Forwarding function for diagnostics. This translate a source
207 /// position in the current buffer into a SourceLocation object for rendering.
208 DiagnosticBuilder Diag(const char *Loc, unsigned DiagID) const;
210 /// getSourceLocation - Return a source location identifier for the specified
211 /// offset in the current file.
212 SourceLocation getSourceLocation(const char *Loc, unsigned TokLen = 1) const;
214 /// getSourceLocation - Return a source location for the next character in
215 /// the current file.
216 SourceLocation getSourceLocation() { return getSourceLocation(BufferPtr); }
218 /// \brief Return the current location in the buffer.
219 const char *getBufferLocation() const { return BufferPtr; }
221 /// Stringify - Convert the specified string into a C string by escaping '\'
222 /// and " characters. This does not add surrounding ""'s to the string.
223 /// If Charify is true, this escapes the ' character instead of ".
224 static std::string Stringify(const std::string &Str, bool Charify = false);
226 /// Stringify - Convert the specified string into a C string by escaping '\'
227 /// and " characters. This does not add surrounding ""'s to the string.
228 static void Stringify(SmallVectorImpl<char> &Str);
231 /// getSpelling - This method is used to get the spelling of a token into a
232 /// preallocated buffer, instead of as an std::string. The caller is required
233 /// to allocate enough space for the token, which is guaranteed to be at least
234 /// Tok.getLength() bytes long. The length of the actual result is returned.
236 /// Note that this method may do two possible things: it may either fill in
237 /// the buffer specified with characters, or it may *change the input pointer*
238 /// to point to a constant buffer with the data already in it (avoiding a
239 /// copy). The caller is not allowed to modify the returned buffer pointer
240 /// if an internal buffer is returned.
241 static unsigned getSpelling(const Token &Tok, const char *&Buffer,
242 const SourceManager &SourceMgr,
243 const LangOptions &LangOpts,
246 /// getSpelling() - Return the 'spelling' of the Tok token. The spelling of a
247 /// token is the characters used to represent the token in the source file
248 /// after trigraph expansion and escaped-newline folding. In particular, this
249 /// wants to get the true, uncanonicalized, spelling of things like digraphs
251 static std::string getSpelling(const Token &Tok,
252 const SourceManager &SourceMgr,
253 const LangOptions &LangOpts,
256 /// getSpelling - This method is used to get the spelling of the
257 /// token at the given source location. If, as is usually true, it
258 /// is not necessary to copy any data, then the returned string may
259 /// not point into the provided buffer.
261 /// This method lexes at the expansion depth of the given
262 /// location and does not jump to the expansion or spelling
264 static StringRef getSpelling(SourceLocation loc,
265 SmallVectorImpl<char> &buffer,
266 const SourceManager &SourceMgr,
267 const LangOptions &LangOpts,
270 /// MeasureTokenLength - Relex the token at the specified location and return
271 /// its length in bytes in the input file. If the token needs cleaning (e.g.
272 /// includes a trigraph or an escaped newline) then this count includes bytes
273 /// that are part of that.
274 static unsigned MeasureTokenLength(SourceLocation Loc,
275 const SourceManager &SM,
276 const LangOptions &LangOpts);
278 /// \brief Given a location any where in a source buffer, find the location
279 /// that corresponds to the beginning of the token in which the original
280 /// source location lands.
283 static SourceLocation GetBeginningOfToken(SourceLocation Loc,
284 const SourceManager &SM,
285 const LangOptions &LangOpts);
287 /// AdvanceToTokenCharacter - If the current SourceLocation specifies a
288 /// location at the start of a token, return a new location that specifies a
289 /// character within the token. This handles trigraphs and escaped newlines.
290 static SourceLocation AdvanceToTokenCharacter(SourceLocation TokStart,
292 const SourceManager &SM,
293 const LangOptions &LangOpts);
295 /// \brief Computes the source location just past the end of the
296 /// token at this source location.
298 /// This routine can be used to produce a source location that
299 /// points just past the end of the token referenced by \p Loc, and
300 /// is generally used when a diagnostic needs to point just after a
301 /// token where it expected something different that it received. If
302 /// the returned source location would not be meaningful (e.g., if
303 /// it points into a macro), this routine returns an invalid
306 /// \param Offset an offset from the end of the token, where the source
307 /// location should refer to. The default offset (0) produces a source
308 /// location pointing just past the end of the token; an offset of 1 produces
309 /// a source location pointing to the last character in the token, etc.
310 static SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset,
311 const SourceManager &SM,
312 const LangOptions &LangOpts);
314 /// \brief Returns true if the given MacroID location points at the first
315 /// token of the macro expansion.
317 /// \param MacroBegin If non-null and function returns true, it is set to
318 /// begin location of the macro.
319 static bool isAtStartOfMacroExpansion(SourceLocation loc,
320 const SourceManager &SM,
321 const LangOptions &LangOpts,
322 SourceLocation *MacroBegin = 0);
324 /// \brief Returns true if the given MacroID location points at the last
325 /// token of the macro expansion.
327 /// \param MacroBegin If non-null and function returns true, it is set to
328 /// end location of the macro.
329 static bool isAtEndOfMacroExpansion(SourceLocation loc,
330 const SourceManager &SM,
331 const LangOptions &LangOpts,
332 SourceLocation *MacroEnd = 0);
334 /// \brief Accepts a range and returns a character range with file locations.
336 /// Returns a null range if a part of the range resides inside a macro
337 /// expansion or the range does not reside on the same FileID.
338 static CharSourceRange makeFileCharRange(CharSourceRange Range,
339 const SourceManager &SM,
340 const LangOptions &LangOpts);
342 /// \brief Returns a string for the source that the range encompasses.
343 static StringRef getSourceText(CharSourceRange Range,
344 const SourceManager &SM,
345 const LangOptions &LangOpts,
348 /// \brief Retrieve the name of the immediate macro expansion.
350 /// This routine starts from a source location, and finds the name of the macro
351 /// responsible for its immediate expansion. It looks through any intervening
352 /// macro argument expansions to compute this. It returns a StringRef which
353 /// refers to the SourceManager-owned buffer of the source where that macro
354 /// name is spelled. Thus, the result shouldn't out-live that SourceManager.
355 static StringRef getImmediateMacroName(SourceLocation Loc,
356 const SourceManager &SM,
357 const LangOptions &LangOpts);
359 /// \brief Compute the preamble of the given file.
361 /// The preamble of a file contains the initial comments, include directives,
362 /// and other preprocessor directives that occur before the code in this
363 /// particular file actually begins. The preamble of the main source file is
364 /// a potential prefix header.
366 /// \param Buffer The memory buffer containing the file's contents.
368 /// \param MaxLines If non-zero, restrict the length of the preamble
369 /// to fewer than this number of lines.
371 /// \returns The offset into the file where the preamble ends and the rest
372 /// of the file begins along with a boolean value indicating whether
373 /// the preamble ends at the beginning of a new line.
374 static std::pair<unsigned, bool>
375 ComputePreamble(const llvm::MemoryBuffer *Buffer, const LangOptions &LangOpts,
376 unsigned MaxLines = 0);
378 //===--------------------------------------------------------------------===//
379 // Internal implementation interfaces.
382 /// LexTokenInternal - Internal interface to lex a preprocessing token. Called
385 void LexTokenInternal(Token &Result);
387 /// FormTokenWithChars - When we lex a token, we have identified a span
388 /// starting at BufferPtr, going to TokEnd that forms the token. This method
389 /// takes that range and assigns it to the token as its location and size. In
390 /// addition, since tokens cannot overlap, this also updates BufferPtr to be
392 void FormTokenWithChars(Token &Result, const char *TokEnd,
393 tok::TokenKind Kind) {
394 unsigned TokLen = TokEnd-BufferPtr;
395 Result.setLength(TokLen);
396 Result.setLocation(getSourceLocation(BufferPtr, TokLen));
397 Result.setKind(Kind);
401 /// isNextPPTokenLParen - Return 1 if the next unexpanded token will return a
402 /// tok::l_paren token, 0 if it is something else and 2 if there are no more
403 /// tokens in the buffer controlled by this lexer.
404 unsigned isNextPPTokenLParen();
406 //===--------------------------------------------------------------------===//
407 // Lexer character reading interfaces.
410 // This lexer is built on two interfaces for reading characters, both of which
411 // automatically provide phase 1/2 translation. getAndAdvanceChar is used
412 // when we know that we will be reading a character from the input buffer and
413 // that this character will be part of the result token. This occurs in (f.e.)
414 // string processing, because we know we need to read until we find the
415 // closing '"' character.
417 // The second interface is the combination of getCharAndSize with
418 // ConsumeChar. getCharAndSize reads a phase 1/2 translated character,
419 // returning it and its size. If the lexer decides that this character is
420 // part of the current token, it calls ConsumeChar on it. This two stage
421 // approach allows us to emit diagnostics for characters (e.g. warnings about
422 // trigraphs), knowing that they only are emitted if the character is
425 /// isObviouslySimpleCharacter - Return true if the specified character is
426 /// obviously the same in translation phase 1 and translation phase 3. This
427 /// can return false for characters that end up being the same, but it will
428 /// never return true for something that needs to be mapped.
429 static bool isObviouslySimpleCharacter(char C) {
430 return C != '?' && C != '\\';
433 /// getAndAdvanceChar - Read a single 'character' from the specified buffer,
434 /// advance over it, and return it. This is tricky in several cases. Here we
435 /// just handle the trivial case and fall-back to the non-inlined
436 /// getCharAndSizeSlow method to handle the hard case.
437 inline char getAndAdvanceChar(const char *&Ptr, Token &Tok) {
438 // If this is not a trigraph and not a UCN or escaped newline, return
440 if (isObviouslySimpleCharacter(Ptr[0])) return *Ptr++;
443 char C = getCharAndSizeSlow(Ptr, Size, &Tok);
449 /// ConsumeChar - When a character (identified by getCharAndSize) is consumed
450 /// and added to a given token, check to see if there are diagnostics that
451 /// need to be emitted or flags that need to be set on the token. If so, do
453 const char *ConsumeChar(const char *Ptr, unsigned Size, Token &Tok) {
454 // Normal case, we consumed exactly one token. Just return it.
458 // Otherwise, re-lex the character with a current token, allowing
459 // diagnostics to be emitted and flags to be set.
461 getCharAndSizeSlow(Ptr, Size, &Tok);
465 /// getCharAndSize - Peek a single 'character' from the specified buffer,
466 /// get its size, and return it. This is tricky in several cases. Here we
467 /// just handle the trivial case and fall-back to the non-inlined
468 /// getCharAndSizeSlow method to handle the hard case.
469 inline char getCharAndSize(const char *Ptr, unsigned &Size) {
470 // If this is not a trigraph and not a UCN or escaped newline, return
472 if (isObviouslySimpleCharacter(Ptr[0])) {
478 return getCharAndSizeSlow(Ptr, Size);
481 /// getCharAndSizeSlow - Handle the slow/uncommon case of the getCharAndSize
483 char getCharAndSizeSlow(const char *Ptr, unsigned &Size, Token *Tok = 0);
486 /// getCharAndSizeNoWarn - Like the getCharAndSize method, but does not ever
488 static inline char getCharAndSizeNoWarn(const char *Ptr, unsigned &Size,
489 const LangOptions &LangOpts) {
490 // If this is not a trigraph and not a UCN or escaped newline, return
492 if (isObviouslySimpleCharacter(Ptr[0])) {
498 return getCharAndSizeSlowNoWarn(Ptr, Size, LangOpts);
501 /// getEscapedNewLineSize - Return the size of the specified escaped newline,
502 /// or 0 if it is not an escaped newline. P[-1] is known to be a "\" on entry
503 /// to this function.
504 static unsigned getEscapedNewLineSize(const char *P);
506 /// SkipEscapedNewLines - If P points to an escaped newline (or a series of
507 /// them), skip over them and return the first non-escaped-newline found,
508 /// otherwise return P.
509 static const char *SkipEscapedNewLines(const char *P);
511 /// \brief Checks that the given token is the first token that occurs after
512 /// the given location (this excludes comments and whitespace). Returns the
513 /// location immediately after the specified token. If the token is not found
514 /// or the location is inside a macro, the returned source location will be
516 static SourceLocation findLocationAfterToken(SourceLocation loc,
517 tok::TokenKind TKind,
518 const SourceManager &SM,
519 const LangOptions &LangOpts,
520 bool SkipTrailingWhitespaceAndNewLine);
524 /// getCharAndSizeSlowNoWarn - Same as getCharAndSizeSlow, but never emits a
526 static char getCharAndSizeSlowNoWarn(const char *Ptr, unsigned &Size,
527 const LangOptions &LangOpts);
529 //===--------------------------------------------------------------------===//
530 // Other lexer functions.
532 void SkipBytes(unsigned Bytes, bool StartOfLine);
534 const char *LexUDSuffix(Token &Result, const char *CurPtr);
536 // Helper functions to lex the remainder of a token of the specific type.
537 void LexIdentifier (Token &Result, const char *CurPtr);
538 void LexNumericConstant (Token &Result, const char *CurPtr);
539 void LexStringLiteral (Token &Result, const char *CurPtr,
540 tok::TokenKind Kind);
541 void LexRawStringLiteral (Token &Result, const char *CurPtr,
542 tok::TokenKind Kind);
543 void LexAngledStringLiteral(Token &Result, const char *CurPtr);
544 void LexCharConstant (Token &Result, const char *CurPtr,
545 tok::TokenKind Kind);
546 bool LexEndOfFile (Token &Result, const char *CurPtr);
548 bool SkipWhitespace (Token &Result, const char *CurPtr);
549 bool SkipBCPLComment (Token &Result, const char *CurPtr);
550 bool SkipBlockComment (Token &Result, const char *CurPtr);
551 bool SaveBCPLComment (Token &Result, const char *CurPtr);
553 bool IsStartOfConflictMarker(const char *CurPtr);
554 bool HandleEndOfConflictMarker(const char *CurPtr);
556 bool isCodeCompletionPoint(const char *CurPtr) const;
557 void cutOffLexing() { BufferPtr = BufferEnd; }
561 } // end namespace clang