Coverage Report

Created: 2022-07-16 07:03

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Lex/Lexer.h
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Count
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//===- Lexer.h - C Language Family Lexer ------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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//  This file defines the Lexer interface.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_LEX_LEXER_H
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#define LLVM_CLANG_LEX_LEXER_H
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#include "clang/Basic/LangOptions.h"
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#include "clang/Basic/SourceLocation.h"
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#include "clang/Basic/TokenKinds.h"
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#include "clang/Lex/DependencyDirectivesScanner.h"
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#include "clang/Lex/PreprocessorLexer.h"
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#include "clang/Lex/Token.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringRef.h"
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#include <cassert>
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#include <cstdint>
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#include <string>
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namespace llvm {
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class MemoryBufferRef;
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33
} // namespace llvm
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35
namespace clang {
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37
class DiagnosticBuilder;
38
class Preprocessor;
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class SourceManager;
40
class LangOptions;
41
42
/// ConflictMarkerKind - Kinds of conflict marker which the lexer might be
43
/// recovering from.
44
enum ConflictMarkerKind {
45
  /// Not within a conflict marker.
46
  CMK_None,
47
48
  /// A normal or diff3 conflict marker, initiated by at least 7 "<"s,
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  /// separated by at least 7 "="s or "|"s, and terminated by at least 7 ">"s.
50
  CMK_Normal,
51
52
  /// A Perforce-style conflict marker, initiated by 4 ">"s,
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  /// separated by 4 "="s, and terminated by 4 "<"s.
54
  CMK_Perforce
55
};
56
57
/// Describes the bounds (start, size) of the preamble and a flag required by
58
/// PreprocessorOptions::PrecompiledPreambleBytes.
59
/// The preamble includes the BOM, if any.
60
struct PreambleBounds {
61
  /// Size of the preamble in bytes.
62
  unsigned Size;
63
64
  /// Whether the preamble ends at the start of a new line.
65
  ///
66
  /// Used to inform the lexer as to whether it's starting at the beginning of
67
  /// a line after skipping the preamble.
68
  bool PreambleEndsAtStartOfLine;
69
70
  PreambleBounds(unsigned Size, bool PreambleEndsAtStartOfLine)
71
1.39k
      : Size(Size), PreambleEndsAtStartOfLine(PreambleEndsAtStartOfLine) {}
72
};
73
74
/// Lexer - This provides a simple interface that turns a text buffer into a
75
/// stream of tokens.  This provides no support for file reading or buffering,
76
/// or buffering/seeking of tokens, only forward lexing is supported.  It relies
77
/// on the specified Preprocessor object to handle preprocessor directives, etc.
78
class Lexer : public PreprocessorLexer {
79
  friend class Preprocessor;
80
81
  void anchor() override;
82
83
  //===--------------------------------------------------------------------===//
84
  // Constant configuration values for this lexer.
85
86
  // Start of the buffer.
87
  const char *BufferStart;
88
89
  // End of the buffer.
90
  const char *BufferEnd;
91
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  // Location for start of file.
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  SourceLocation FileLoc;
94
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  // LangOpts enabled by this language.
96
  // Storing LangOptions as reference here is important from performance point
97
  // of view. Lack of reference means that LangOptions copy constructor would be
98
  // called by Lexer(..., const LangOptions &LangOpts,...). Given that local
99
  // Lexer objects are created thousands times (in Lexer::getRawToken,
100
  // Preprocessor::EnterSourceFile and other places) during single module
101
  // processing in frontend it would make std::vector<std::string> copy
102
  // constructors surprisingly hot.
103
  const LangOptions &LangOpts;
104
105
  // True if '//' line comments are enabled.
106
  bool LineComment;
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108
  // True if lexer for _Pragma handling.
109
  bool Is_PragmaLexer;
110
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  //===--------------------------------------------------------------------===//
112
  // Context-specific lexing flags set by the preprocessor.
113
  //
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115
  /// ExtendedTokenMode - The lexer can optionally keep comments and whitespace
116
  /// and return them as tokens.  This is used for -C and -CC modes, and
117
  /// whitespace preservation can be useful for some clients that want to lex
118
  /// the file in raw mode and get every character from the file.
119
  ///
120
  /// When this is set to 2 it returns comments and whitespace.  When set to 1
121
  /// it returns comments, when it is set to 0 it returns normal tokens only.
122
  unsigned char ExtendedTokenMode;
123
124
  //===--------------------------------------------------------------------===//
125
  // Context that changes as the file is lexed.
126
  // NOTE: any state that mutates when in raw mode must have save/restore code
127
  // in Lexer::isNextPPTokenLParen.
128
129
  // BufferPtr - Current pointer into the buffer.  This is the next character
130
  // to be lexed.
131
  const char *BufferPtr;
132
133
  // IsAtStartOfLine - True if the next lexed token should get the "start of
134
  // line" flag set on it.
135
  bool IsAtStartOfLine;
136
137
  bool IsAtPhysicalStartOfLine;
138
139
  bool HasLeadingSpace;
140
141
  bool HasLeadingEmptyMacro;
142
143
  /// True if this is the first time we're lexing the input file.
144
  bool IsFirstTimeLexingFile;
145
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  // NewLinePtr - A pointer to new line character '\n' being lexed. For '\r\n',
147
  // it also points to '\n.'
148
  const char *NewLinePtr;
149
150
  // CurrentConflictMarkerState - The kind of conflict marker we are handling.
151
  ConflictMarkerKind CurrentConflictMarkerState;
152
153
  /// Non-empty if this \p Lexer is \p isDependencyDirectivesLexer().
154
  ArrayRef<dependency_directives_scan::Directive> DepDirectives;
155
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  /// If this \p Lexer is \p isDependencyDirectivesLexer(), it represents the
157
  /// next token to use from the current dependency directive.
158
  unsigned NextDepDirectiveTokenIndex = 0;
159
160
  void InitLexer(const char *BufStart, const char *BufPtr, const char *BufEnd);
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public:
163
  /// Lexer constructor - Create a new lexer object for the specified buffer
164
  /// with the specified preprocessor managing the lexing process.  This lexer
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  /// assumes that the associated file buffer and Preprocessor objects will
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  /// outlive it, so it doesn't take ownership of either of them.
167
  Lexer(FileID FID, const llvm::MemoryBufferRef &InputFile, Preprocessor &PP,
168
        bool IsFirstIncludeOfFile = true);
169
170
  /// Lexer constructor - Create a new raw lexer object.  This object is only
171
  /// suitable for calls to 'LexFromRawLexer'.  This lexer assumes that the
172
  /// text range will outlive it, so it doesn't take ownership of it.
173
  Lexer(SourceLocation FileLoc, const LangOptions &LangOpts,
174
        const char *BufStart, const char *BufPtr, const char *BufEnd,
175
        bool IsFirstIncludeOfFile = true);
176
177
  /// Lexer constructor - Create a new raw lexer object.  This object is only
178
  /// suitable for calls to 'LexFromRawLexer'.  This lexer assumes that the
179
  /// text range will outlive it, so it doesn't take ownership of it.
180
  Lexer(FileID FID, const llvm::MemoryBufferRef &FromFile,
181
        const SourceManager &SM, const LangOptions &LangOpts,
182
        bool IsFirstIncludeOfFile = true);
183
184
  Lexer(const Lexer &) = delete;
185
  Lexer &operator=(const Lexer &) = delete;
186
187
  /// Create_PragmaLexer: Lexer constructor - Create a new lexer object for
188
  /// _Pragma expansion.  This has a variety of magic semantics that this method
189
  /// sets up.  It returns a new'd Lexer that must be delete'd when done.
190
  static Lexer *Create_PragmaLexer(SourceLocation SpellingLoc,
191
                                   SourceLocation ExpansionLocStart,
192
                                   SourceLocation ExpansionLocEnd,
193
                                   unsigned TokLen, Preprocessor &PP);
194
195
  /// getFileLoc - Return the File Location for the file we are lexing out of.
196
  /// The physical location encodes the location where the characters come from,
197
  /// the virtual location encodes where we should *claim* the characters came
198
  /// from.  Currently this is only used by _Pragma handling.
199
1.81M
  SourceLocation getFileLoc() const { return FileLoc; }
200
201
private:
202
  /// Lex - Return the next token in the file.  If this is the end of file, it
203
  /// return the tok::eof token.  This implicitly involves the preprocessor.
204
  bool Lex(Token &Result);
205
206
  /// Called when the preprocessor is in 'dependency scanning lexing mode'.
207
  bool LexDependencyDirectiveToken(Token &Result);
208
209
  /// Called when the preprocessor is in 'dependency scanning lexing mode' and
210
  /// is skipping a conditional block.
211
  bool LexDependencyDirectiveTokenWhileSkipping(Token &Result);
212
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  /// True when the preprocessor is in 'dependency scanning lexing mode' and
214
  /// created this \p Lexer for lexing a set of dependency directive tokens.
215
1.58G
  bool isDependencyDirectivesLexer() const { return !DepDirectives.empty(); }
216
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  /// Initializes \p Result with data from \p DDTok and advances \p BufferPtr to
218
  /// the position just after the token.
219
  /// \returns the buffer pointer at the beginning of the token.
220
  const char *convertDependencyDirectiveToken(
221
      const dependency_directives_scan::Token &DDTok, Token &Result);
222
223
public:
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  /// isPragmaLexer - Returns true if this Lexer is being used to lex a pragma.
225
4.44M
  bool isPragmaLexer() const { return Is_PragmaLexer; }
226
227
private:
228
  /// IndirectLex - An indirect call to 'Lex' that can be invoked via
229
  ///  the PreprocessorLexer interface.
230
13.0k
  void IndirectLex(Token &Result) override { Lex(Result); }
231
232
public:
233
  /// LexFromRawLexer - Lex a token from a designated raw lexer (one with no
234
  /// associated preprocessor object.  Return true if the 'next character to
235
  /// read' pointer points at the end of the lexer buffer, false otherwise.
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70.6M
  bool LexFromRawLexer(Token &Result) {
237
70.6M
    assert(LexingRawMode && "Not already in raw mode!");
238
0
    Lex(Result);
239
    // Note that lexing to the end of the buffer doesn't implicitly delete the
240
    // lexer when in raw mode.
241
70.6M
    return BufferPtr == BufferEnd;
242
70.6M
  }
243
244
  /// isKeepWhitespaceMode - Return true if the lexer should return tokens for
245
  /// every character in the file, including whitespace and comments.  This
246
  /// should only be used in raw mode, as the preprocessor is not prepared to
247
  /// deal with the excess tokens.
248
792M
  bool isKeepWhitespaceMode() const {
249
792M
    return ExtendedTokenMode > 1;
250
792M
  }
251
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  /// SetKeepWhitespaceMode - This method lets clients enable or disable
253
  /// whitespace retention mode.
254
78.7M
  void SetKeepWhitespaceMode(bool Val) {
255
78.7M
    assert((!Val || LexingRawMode || LangOpts.TraditionalCPP) &&
256
78.7M
           "Can only retain whitespace in raw mode or -traditional-cpp");
257
78.7M
    ExtendedTokenMode = Val ? 
280.8k
:
078.6M
;
258
78.7M
  }
259
260
  /// inKeepCommentMode - Return true if the lexer should return comments as
261
  /// tokens.
262
91.6M
  bool inKeepCommentMode() const {
263
91.6M
    return ExtendedTokenMode > 0;
264
91.6M
  }
265
266
  /// SetCommentRetentionMode - Change the comment retention mode of the lexer
267
  /// to the specified mode.  This is really only useful when lexing in raw
268
  /// mode, because otherwise the lexer needs to manage this.
269
180M
  void SetCommentRetentionState(bool Mode) {
270
180M
    assert(!isKeepWhitespaceMode() &&
271
180M
           "Can't play with comment retention state when retaining whitespace");
272
180M
    ExtendedTokenMode = Mode ? 
150.8M
:
0129M
;
273
180M
  }
274
275
  /// Sets the extended token mode back to its initial value, according to the
276
  /// language options and preprocessor. This controls whether the lexer
277
  /// produces comment and whitespace tokens.
278
  ///
279
  /// This requires the lexer to have an associated preprocessor. A standalone
280
  /// lexer has nothing to reset to.
281
  void resetExtendedTokenMode();
282
283
  /// Gets source code buffer.
284
6.70k
  StringRef getBuffer() const {
285
6.70k
    return StringRef(BufferStart, BufferEnd - BufferStart);
286
6.70k
  }
287
288
  /// ReadToEndOfLine - Read the rest of the current preprocessor line as an
289
  /// uninterpreted string.  This switches the lexer out of directive mode.
290
  void ReadToEndOfLine(SmallVectorImpl<char> *Result = nullptr);
291
292
293
  /// Diag - Forwarding function for diagnostics.  This translate a source
294
  /// position in the current buffer into a SourceLocation object for rendering.
295
  DiagnosticBuilder Diag(const char *Loc, unsigned DiagID) const;
296
297
  /// getSourceLocation - Return a source location identifier for the specified
298
  /// offset in the current file.
299
  SourceLocation getSourceLocation(const char *Loc, unsigned TokLen = 1) const;
300
301
  /// getSourceLocation - Return a source location for the next character in
302
  /// the current file.
303
1.97M
  SourceLocation getSourceLocation() override {
304
1.97M
    return getSourceLocation(BufferPtr);
305
1.97M
  }
306
307
  /// Return the current location in the buffer.
308
16.7M
  const char *getBufferLocation() const { return BufferPtr; }
309
310
  /// Returns the current lexing offset.
311
3.93M
  unsigned getCurrentBufferOffset() {
312
3.93M
    assert(BufferPtr >= BufferStart && "Invalid buffer state");
313
0
    return BufferPtr - BufferStart;
314
3.93M
  }
315
316
  /// Set the lexer's buffer pointer to \p Offset.
317
  void seek(unsigned Offset, bool IsAtStartOfLine);
318
319
  /// Stringify - Convert the specified string into a C string by i) escaping
320
  /// '\\' and " characters and ii) replacing newline character(s) with "\\n".
321
  /// If Charify is true, this escapes the ' character instead of ".
322
  static std::string Stringify(StringRef Str, bool Charify = false);
323
324
  /// Stringify - Convert the specified string into a C string by i) escaping
325
  /// '\\' and " characters and ii) replacing newline character(s) with "\\n".
326
  static void Stringify(SmallVectorImpl<char> &Str);
327
328
  /// getSpelling - This method is used to get the spelling of a token into a
329
  /// preallocated buffer, instead of as an std::string.  The caller is required
330
  /// to allocate enough space for the token, which is guaranteed to be at least
331
  /// Tok.getLength() bytes long.  The length of the actual result is returned.
332
  ///
333
  /// Note that this method may do two possible things: it may either fill in
334
  /// the buffer specified with characters, or it may *change the input pointer*
335
  /// to point to a constant buffer with the data already in it (avoiding a
336
  /// copy).  The caller is not allowed to modify the returned buffer pointer
337
  /// if an internal buffer is returned.
338
  static unsigned getSpelling(const Token &Tok, const char *&Buffer,
339
                              const SourceManager &SourceMgr,
340
                              const LangOptions &LangOpts,
341
                              bool *Invalid = nullptr);
342
343
  /// getSpelling() - Return the 'spelling' of the Tok token.  The spelling of a
344
  /// token is the characters used to represent the token in the source file
345
  /// after trigraph expansion and escaped-newline folding.  In particular, this
346
  /// wants to get the true, uncanonicalized, spelling of things like digraphs
347
  /// UCNs, etc.
348
  static std::string getSpelling(const Token &Tok,
349
                                 const SourceManager &SourceMgr,
350
                                 const LangOptions &LangOpts,
351
                                 bool *Invalid = nullptr);
352
353
  /// getSpelling - This method is used to get the spelling of the
354
  /// token at the given source location.  If, as is usually true, it
355
  /// is not necessary to copy any data, then the returned string may
356
  /// not point into the provided buffer.
357
  ///
358
  /// This method lexes at the expansion depth of the given
359
  /// location and does not jump to the expansion or spelling
360
  /// location.
361
  static StringRef getSpelling(SourceLocation loc,
362
                               SmallVectorImpl<char> &buffer,
363
                               const SourceManager &SM,
364
                               const LangOptions &options,
365
                               bool *invalid = nullptr);
366
367
  /// MeasureTokenLength - Relex the token at the specified location and return
368
  /// its length in bytes in the input file.  If the token needs cleaning (e.g.
369
  /// includes a trigraph or an escaped newline) then this count includes bytes
370
  /// that are part of that.
371
  static unsigned MeasureTokenLength(SourceLocation Loc,
372
                                     const SourceManager &SM,
373
                                     const LangOptions &LangOpts);
374
375
  /// Relex the token at the specified location.
376
  /// \returns true if there was a failure, false on success.
377
  static bool getRawToken(SourceLocation Loc, Token &Result,
378
                          const SourceManager &SM,
379
                          const LangOptions &LangOpts,
380
                          bool IgnoreWhiteSpace = false);
381
382
  /// Given a location any where in a source buffer, find the location
383
  /// that corresponds to the beginning of the token in which the original
384
  /// source location lands.
385
  static SourceLocation GetBeginningOfToken(SourceLocation Loc,
386
                                            const SourceManager &SM,
387
                                            const LangOptions &LangOpts);
388
389
  /// Get the physical length (including trigraphs and escaped newlines) of the
390
  /// first \p Characters characters of the token starting at TokStart.
391
  static unsigned getTokenPrefixLength(SourceLocation TokStart,
392
                                       unsigned CharNo,
393
                                       const SourceManager &SM,
394
                                       const LangOptions &LangOpts);
395
396
  /// AdvanceToTokenCharacter - If the current SourceLocation specifies a
397
  /// location at the start of a token, return a new location that specifies a
398
  /// character within the token.  This handles trigraphs and escaped newlines.
399
  static SourceLocation AdvanceToTokenCharacter(SourceLocation TokStart,
400
                                                unsigned Characters,
401
                                                const SourceManager &SM,
402
60.8k
                                                const LangOptions &LangOpts) {
403
60.8k
    return TokStart.getLocWithOffset(
404
60.8k
        getTokenPrefixLength(TokStart, Characters, SM, LangOpts));
405
60.8k
  }
406
407
  /// Computes the source location just past the end of the
408
  /// token at this source location.
409
  ///
410
  /// This routine can be used to produce a source location that
411
  /// points just past the end of the token referenced by \p Loc, and
412
  /// is generally used when a diagnostic needs to point just after a
413
  /// token where it expected something different that it received. If
414
  /// the returned source location would not be meaningful (e.g., if
415
  /// it points into a macro), this routine returns an invalid
416
  /// source location.
417
  ///
418
  /// \param Offset an offset from the end of the token, where the source
419
  /// location should refer to. The default offset (0) produces a source
420
  /// location pointing just past the end of the token; an offset of 1 produces
421
  /// a source location pointing to the last character in the token, etc.
422
  static SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset,
423
                                            const SourceManager &SM,
424
                                            const LangOptions &LangOpts);
425
426
  /// Given a token range, produce a corresponding CharSourceRange that
427
  /// is not a token range. This allows the source range to be used by
428
  /// components that don't have access to the lexer and thus can't find the
429
  /// end of the range for themselves.
430
  static CharSourceRange getAsCharRange(SourceRange Range,
431
                                        const SourceManager &SM,
432
6.48k
                                        const LangOptions &LangOpts) {
433
6.48k
    SourceLocation End = getLocForEndOfToken(Range.getEnd(), 0, SM, LangOpts);
434
6.48k
    return End.isInvalid() ? 
CharSourceRange()1
435
6.48k
                           : CharSourceRange::getCharRange(
436
6.48k
                                 Range.getBegin(), End);
437
6.48k
  }
438
  static CharSourceRange getAsCharRange(CharSourceRange Range,
439
                                        const SourceManager &SM,
440
2.07k
                                        const LangOptions &LangOpts) {
441
2.07k
    return Range.isTokenRange()
442
2.07k
               ? 
getAsCharRange(Range.getAsRange(), SM, LangOpts)2.03k
443
2.07k
               : 
Range41
;
444
2.07k
  }
445
446
  /// Returns true if the given MacroID location points at the first
447
  /// token of the macro expansion.
448
  ///
449
  /// \param MacroBegin If non-null and function returns true, it is set to
450
  /// begin location of the macro.
451
  static bool isAtStartOfMacroExpansion(SourceLocation loc,
452
                                        const SourceManager &SM,
453
                                        const LangOptions &LangOpts,
454
                                        SourceLocation *MacroBegin = nullptr);
455
456
  /// Returns true if the given MacroID location points at the last
457
  /// token of the macro expansion.
458
  ///
459
  /// \param MacroEnd If non-null and function returns true, it is set to
460
  /// end location of the macro.
461
  static bool isAtEndOfMacroExpansion(SourceLocation loc,
462
                                      const SourceManager &SM,
463
                                      const LangOptions &LangOpts,
464
                                      SourceLocation *MacroEnd = nullptr);
465
466
  /// Accepts a range and returns a character range with file locations.
467
  ///
468
  /// Returns a null range if a part of the range resides inside a macro
469
  /// expansion or the range does not reside on the same FileID.
470
  ///
471
  /// This function is trying to deal with macros and return a range based on
472
  /// file locations. The cases where it can successfully handle macros are:
473
  ///
474
  /// -begin or end range lies at the start or end of a macro expansion, in
475
  ///  which case the location will be set to the expansion point, e.g:
476
  ///    \#define M 1 2
477
  ///    a M
478
  /// If you have a range [a, 2] (where 2 came from the macro), the function
479
  /// will return a range for "a M"
480
  /// if you have range [a, 1], the function will fail because the range
481
  /// overlaps with only a part of the macro
482
  ///
483
  /// -The macro is a function macro and the range can be mapped to the macro
484
  ///  arguments, e.g:
485
  ///    \#define M 1 2
486
  ///    \#define FM(x) x
487
  ///    FM(a b M)
488
  /// if you have range [b, 2], the function will return the file range "b M"
489
  /// inside the macro arguments.
490
  /// if you have range [a, 2], the function will return the file range
491
  /// "FM(a b M)" since the range includes all of the macro expansion.
492
  static CharSourceRange makeFileCharRange(CharSourceRange Range,
493
                                           const SourceManager &SM,
494
                                           const LangOptions &LangOpts);
495
496
  /// Returns a string for the source that the range encompasses.
497
  static StringRef getSourceText(CharSourceRange Range,
498
                                 const SourceManager &SM,
499
                                 const LangOptions &LangOpts,
500
                                 bool *Invalid = nullptr);
501
502
  /// Retrieve the name of the immediate macro expansion.
503
  ///
504
  /// This routine starts from a source location, and finds the name of the macro
505
  /// responsible for its immediate expansion. It looks through any intervening
506
  /// macro argument expansions to compute this. It returns a StringRef which
507
  /// refers to the SourceManager-owned buffer of the source where that macro
508
  /// name is spelled. Thus, the result shouldn't out-live that SourceManager.
509
  static StringRef getImmediateMacroName(SourceLocation Loc,
510
                                         const SourceManager &SM,
511
                                         const LangOptions &LangOpts);
512
513
  /// Retrieve the name of the immediate macro expansion.
514
  ///
515
  /// This routine starts from a source location, and finds the name of the
516
  /// macro responsible for its immediate expansion. It looks through any
517
  /// intervening macro argument expansions to compute this. It returns a
518
  /// StringRef which refers to the SourceManager-owned buffer of the source
519
  /// where that macro name is spelled. Thus, the result shouldn't out-live
520
  /// that SourceManager.
521
  ///
522
  /// This differs from Lexer::getImmediateMacroName in that any macro argument
523
  /// location will result in the topmost function macro that accepted it.
524
  /// e.g.
525
  /// \code
526
  ///   MAC1( MAC2(foo) )
527
  /// \endcode
528
  /// for location of 'foo' token, this function will return "MAC1" while
529
  /// Lexer::getImmediateMacroName will return "MAC2".
530
  static StringRef getImmediateMacroNameForDiagnostics(
531
      SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts);
532
533
  /// Compute the preamble of the given file.
534
  ///
535
  /// The preamble of a file contains the initial comments, include directives,
536
  /// and other preprocessor directives that occur before the code in this
537
  /// particular file actually begins. The preamble of the main source file is
538
  /// a potential prefix header.
539
  ///
540
  /// \param Buffer The memory buffer containing the file's contents.
541
  ///
542
  /// \param MaxLines If non-zero, restrict the length of the preamble
543
  /// to fewer than this number of lines.
544
  ///
545
  /// \returns The offset into the file where the preamble ends and the rest
546
  /// of the file begins along with a boolean value indicating whether
547
  /// the preamble ends at the beginning of a new line.
548
  static PreambleBounds ComputePreamble(StringRef Buffer,
549
                                        const LangOptions &LangOpts,
550
                                        unsigned MaxLines = 0);
551
552
  /// Finds the token that comes right after the given location.
553
  ///
554
  /// Returns the next token, or none if the location is inside a macro.
555
  static Optional<Token> findNextToken(SourceLocation Loc,
556
                                       const SourceManager &SM,
557
                                       const LangOptions &LangOpts);
558
559
  /// Checks that the given token is the first token that occurs after
560
  /// the given location (this excludes comments and whitespace). Returns the
561
  /// location immediately after the specified token. If the token is not found
562
  /// or the location is inside a macro, the returned source location will be
563
  /// invalid.
564
  static SourceLocation findLocationAfterToken(SourceLocation loc,
565
                                         tok::TokenKind TKind,
566
                                         const SourceManager &SM,
567
                                         const LangOptions &LangOpts,
568
                                         bool SkipTrailingWhitespaceAndNewLine);
569
570
  /// Returns true if the given character could appear in an identifier.
571
  static bool isAsciiIdentifierContinueChar(char c,
572
                                            const LangOptions &LangOpts);
573
574
  /// Checks whether new line pointed by Str is preceded by escape
575
  /// sequence.
576
  static bool isNewLineEscaped(const char *BufferStart, const char *Str);
577
578
  /// getCharAndSizeNoWarn - Like the getCharAndSize method, but does not ever
579
  /// emit a warning.
580
  static inline char getCharAndSizeNoWarn(const char *Ptr, unsigned &Size,
581
315k
                                          const LangOptions &LangOpts) {
582
    // If this is not a trigraph and not a UCN or escaped newline, return
583
    // quickly.
584
315k
    if (isObviouslySimpleCharacter(Ptr[0])) {
585
304k
      Size = 1;
586
304k
      return *Ptr;
587
304k
    }
588
589
11.4k
    Size = 0;
590
11.4k
    return getCharAndSizeSlowNoWarn(Ptr, Size, LangOpts);
591
315k
  }
592
593
  /// Returns the leading whitespace for line that corresponds to the given
594
  /// location \p Loc.
595
  static StringRef getIndentationForLine(SourceLocation Loc,
596
                                         const SourceManager &SM);
597
598
  /// Check if this is the first time we're lexing the input file.
599
14
  bool isFirstTimeLexingFile() const { return IsFirstTimeLexingFile; }
600
601
private:
602
  //===--------------------------------------------------------------------===//
603
  // Internal implementation interfaces.
604
605
  /// LexTokenInternal - Internal interface to lex a preprocessing token. Called
606
  /// by Lex.
607
  ///
608
  bool LexTokenInternal(Token &Result, bool TokAtPhysicalStartOfLine);
609
610
  bool CheckUnicodeWhitespace(Token &Result, uint32_t C, const char *CurPtr);
611
612
  bool LexUnicodeIdentifierStart(Token &Result, uint32_t C, const char *CurPtr);
613
614
  /// FormTokenWithChars - When we lex a token, we have identified a span
615
  /// starting at BufferPtr, going to TokEnd that forms the token.  This method
616
  /// takes that range and assigns it to the token as its location and size.  In
617
  /// addition, since tokens cannot overlap, this also updates BufferPtr to be
618
  /// TokEnd.
619
  void FormTokenWithChars(Token &Result, const char *TokEnd,
620
1.56G
                          tok::TokenKind Kind) {
621
1.56G
    unsigned TokLen = TokEnd-BufferPtr;
622
1.56G
    Result.setLength(TokLen);
623
1.56G
    Result.setLocation(getSourceLocation(BufferPtr, TokLen));
624
1.56G
    Result.setKind(Kind);
625
1.56G
    BufferPtr = TokEnd;
626
1.56G
  }
627
628
  /// isNextPPTokenLParen - Return 1 if the next unexpanded token will return a
629
  /// tok::l_paren token, 0 if it is something else and 2 if there are no more
630
  /// tokens in the buffer controlled by this lexer.
631
  unsigned isNextPPTokenLParen();
632
633
  //===--------------------------------------------------------------------===//
634
  // Lexer character reading interfaces.
635
636
  // This lexer is built on two interfaces for reading characters, both of which
637
  // automatically provide phase 1/2 translation.  getAndAdvanceChar is used
638
  // when we know that we will be reading a character from the input buffer and
639
  // that this character will be part of the result token. This occurs in (f.e.)
640
  // string processing, because we know we need to read until we find the
641
  // closing '"' character.
642
  //
643
  // The second interface is the combination of getCharAndSize with
644
  // ConsumeChar.  getCharAndSize reads a phase 1/2 translated character,
645
  // returning it and its size.  If the lexer decides that this character is
646
  // part of the current token, it calls ConsumeChar on it.  This two stage
647
  // approach allows us to emit diagnostics for characters (e.g. warnings about
648
  // trigraphs), knowing that they only are emitted if the character is
649
  // consumed.
650
651
  /// isObviouslySimpleCharacter - Return true if the specified character is
652
  /// obviously the same in translation phase 1 and translation phase 3.  This
653
  /// can return false for characters that end up being the same, but it will
654
  /// never return true for something that needs to be mapped.
655
3.08G
  static bool isObviouslySimpleCharacter(char C) {
656
3.08G
    return C != '?' && 
C != '\\'3.08G
;
657
3.08G
  }
658
659
  /// getAndAdvanceChar - Read a single 'character' from the specified buffer,
660
  /// advance over it, and return it.  This is tricky in several cases.  Here we
661
  /// just handle the trivial case and fall-back to the non-inlined
662
  /// getCharAndSizeSlow method to handle the hard case.
663
1.94G
  inline char getAndAdvanceChar(const char *&Ptr, Token &Tok) {
664
    // If this is not a trigraph and not a UCN or escaped newline, return
665
    // quickly.
666
1.94G
    if (isObviouslySimpleCharacter(Ptr[0])) 
return *Ptr++1.94G
;
667
668
6.97M
    unsigned Size = 0;
669
6.97M
    char C = getCharAndSizeSlow(Ptr, Size, &Tok);
670
6.97M
    Ptr += Size;
671
6.97M
    return C;
672
1.94G
  }
673
674
  /// ConsumeChar - When a character (identified by getCharAndSize) is consumed
675
  /// and added to a given token, check to see if there are diagnostics that
676
  /// need to be emitted or flags that need to be set on the token.  If so, do
677
  /// it.
678
202M
  const char *ConsumeChar(const char *Ptr, unsigned Size, Token &Tok) {
679
    // Normal case, we consumed exactly one token.  Just return it.
680
202M
    if (Size == 1)
681
202M
      return Ptr+Size;
682
683
    // Otherwise, re-lex the character with a current token, allowing
684
    // diagnostics to be emitted and flags to be set.
685
88
    Size = 0;
686
88
    getCharAndSizeSlow(Ptr, Size, &Tok);
687
88
    return Ptr+Size;
688
202M
  }
689
690
  /// getCharAndSize - Peek a single 'character' from the specified buffer,
691
  /// get its size, and return it.  This is tricky in several cases.  Here we
692
  /// just handle the trivial case and fall-back to the non-inlined
693
  /// getCharAndSizeSlow method to handle the hard case.
694
1.13G
  inline char getCharAndSize(const char *Ptr, unsigned &Size) {
695
    // If this is not a trigraph and not a UCN or escaped newline, return
696
    // quickly.
697
1.13G
    if (isObviouslySimpleCharacter(Ptr[0])) {
698
1.13G
      Size = 1;
699
1.13G
      return *Ptr;
700
1.13G
    }
701
702
421
    Size = 0;
703
421
    return getCharAndSizeSlow(Ptr, Size);
704
1.13G
  }
705
706
  /// getCharAndSizeSlow - Handle the slow/uncommon case of the getCharAndSize
707
  /// method.
708
  char getCharAndSizeSlow(const char *Ptr, unsigned &Size,
709
                          Token *Tok = nullptr);
710
711
  /// getEscapedNewLineSize - Return the size of the specified escaped newline,
712
  /// or 0 if it is not an escaped newline. P[-1] is known to be a "\" on entry
713
  /// to this function.
714
  static unsigned getEscapedNewLineSize(const char *P);
715
716
  /// SkipEscapedNewLines - If P points to an escaped newline (or a series of
717
  /// them), skip over them and return the first non-escaped-newline found,
718
  /// otherwise return P.
719
  static const char *SkipEscapedNewLines(const char *P);
720
721
  /// getCharAndSizeSlowNoWarn - Same as getCharAndSizeSlow, but never emits a
722
  /// diagnostic.
723
  static char getCharAndSizeSlowNoWarn(const char *Ptr, unsigned &Size,
724
                                       const LangOptions &LangOpts);
725
726
  //===--------------------------------------------------------------------===//
727
  // Other lexer functions.
728
729
  void SetByteOffset(unsigned Offset, bool StartOfLine);
730
731
  void PropagateLineStartLeadingSpaceInfo(Token &Result);
732
733
  const char *LexUDSuffix(Token &Result, const char *CurPtr,
734
                          bool IsStringLiteral);
735
736
  // Helper functions to lex the remainder of a token of the specific type.
737
738
  // This function handles both ASCII and Unicode identifiers after
739
  // the first codepoint of the identifyier has been parsed.
740
  bool LexIdentifierContinue(Token &Result, const char *CurPtr);
741
742
  bool LexNumericConstant    (Token &Result, const char *CurPtr);
743
  bool LexStringLiteral      (Token &Result, const char *CurPtr,
744
                              tok::TokenKind Kind);
745
  bool LexRawStringLiteral   (Token &Result, const char *CurPtr,
746
                              tok::TokenKind Kind);
747
  bool LexAngledStringLiteral(Token &Result, const char *CurPtr);
748
  bool LexCharConstant       (Token &Result, const char *CurPtr,
749
                              tok::TokenKind Kind);
750
  bool LexEndOfFile          (Token &Result, const char *CurPtr);
751
  bool SkipWhitespace        (Token &Result, const char *CurPtr,
752
                              bool &TokAtPhysicalStartOfLine);
753
  bool SkipLineComment       (Token &Result, const char *CurPtr,
754
                              bool &TokAtPhysicalStartOfLine);
755
  bool SkipBlockComment      (Token &Result, const char *CurPtr,
756
                              bool &TokAtPhysicalStartOfLine);
757
  bool SaveLineComment       (Token &Result, const char *CurPtr);
758
759
  bool IsStartOfConflictMarker(const char *CurPtr);
760
  bool HandleEndOfConflictMarker(const char *CurPtr);
761
762
  bool lexEditorPlaceholder(Token &Result, const char *CurPtr);
763
764
  bool isCodeCompletionPoint(const char *CurPtr) const;
765
66
  void cutOffLexing() { BufferPtr = BufferEnd; }
766
767
  bool isHexaLiteral(const char *Start, const LangOptions &LangOpts);
768
769
  void codeCompleteIncludedFile(const char *PathStart,
770
                                const char *CompletionPoint, bool IsAngled);
771
772
  llvm::Optional<uint32_t>
773
  tryReadNumericUCN(const char *&StartPtr, const char *SlashLoc, Token *Result);
774
  llvm::Optional<uint32_t> tryReadNamedUCN(const char *&StartPtr,
775
                                           Token *Result);
776
777
  /// Read a universal character name.
778
  ///
779
  /// \param StartPtr The position in the source buffer after the initial '\'.
780
  ///                 If the UCN is syntactically well-formed (but not
781
  ///                 necessarily valid), this parameter will be updated to
782
  ///                 point to the character after the UCN.
783
  /// \param SlashLoc The position in the source buffer of the '\'.
784
  /// \param Result   The token being formed. Pass \c nullptr to suppress
785
  ///                 diagnostics and handle token formation in the caller.
786
  ///
787
  /// \return The Unicode codepoint specified by the UCN, or 0 if the UCN is
788
  ///         invalid.
789
  uint32_t tryReadUCN(const char *&StartPtr, const char *SlashLoc, Token *Result);
790
791
  /// Try to consume a UCN as part of an identifier at the current
792
  /// location.
793
  /// \param CurPtr Initially points to the range of characters in the source
794
  ///               buffer containing the '\'. Updated to point past the end of
795
  ///               the UCN on success.
796
  /// \param Size The number of characters occupied by the '\' (including
797
  ///             trigraphs and escaped newlines).
798
  /// \param Result The token being produced. Marked as containing a UCN on
799
  ///               success.
800
  /// \return \c true if a UCN was lexed and it produced an acceptable
801
  ///         identifier character, \c false otherwise.
802
  bool tryConsumeIdentifierUCN(const char *&CurPtr, unsigned Size,
803
                               Token &Result);
804
805
  /// Try to consume an identifier character encoded in UTF-8.
806
  /// \param CurPtr Points to the start of the (potential) UTF-8 code unit
807
  ///        sequence. On success, updated to point past the end of it.
808
  /// \return \c true if a UTF-8 sequence mapping to an acceptable identifier
809
  ///         character was lexed, \c false otherwise.
810
  bool tryConsumeIdentifierUTF8Char(const char *&CurPtr);
811
};
812
813
} // namespace clang
814
815
#endif // LLVM_CLANG_LEX_LEXER_H