clang  3.9.0
PreprocessorLexer.h
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1 //===--- PreprocessorLexer.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 /// \file
11 /// \brief Defines the PreprocessorLexer interface.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_LEX_PREPROCESSORLEXER_H
16 #define LLVM_CLANG_LEX_PREPROCESSORLEXER_H
17 
19 #include "clang/Lex/Token.h"
20 #include "llvm/ADT/SmallVector.h"
21 
22 namespace clang {
23 
24 class FileEntry;
25 class Preprocessor;
26 
28  virtual void anchor();
29 protected:
30  Preprocessor *PP; // Preprocessor object controlling lexing.
31 
32  /// The SourceManager FileID corresponding to the file being lexed.
33  const FileID FID;
34 
35  /// \brief Number of SLocEntries before lexing the file.
37 
38  //===--------------------------------------------------------------------===//
39  // Context-specific lexing flags set by the preprocessor.
40  //===--------------------------------------------------------------------===//
41 
42  /// \brief True when parsing \#XXX; turns '\\n' into a tok::eod token.
44 
45  /// \brief True after \#include; turns <xx> into a tok::angle_string_literal
46  /// token.
48 
49  /// \brief True if in raw mode.
50  ///
51  /// Raw mode disables interpretation of tokens and is a far faster mode to
52  /// lex in than non-raw-mode. This flag:
53  /// 1. If EOF of the current lexer is found, the include stack isn't popped.
54  /// 2. Identifier information is not looked up for identifier tokens. As an
55  /// effect of this, implicit macro expansion is naturally disabled.
56  /// 3. "#" tokens at the start of a line are treated as normal tokens, not
57  /// implicitly transformed by the lexer.
58  /// 4. All diagnostic messages are disabled.
59  /// 5. No callbacks are made into the preprocessor.
60  ///
61  /// Note that in raw mode that the PP pointer may be null.
63 
64  /// \brief A state machine that detects the \#ifndef-wrapping a file
65  /// idiom for the multiple-include optimization.
67 
68  /// \brief Information about the set of \#if/\#ifdef/\#ifndef blocks
69  /// we are currently in.
71 
72  PreprocessorLexer(const PreprocessorLexer &) = delete;
73  void operator=(const PreprocessorLexer &) = delete;
74  friend class Preprocessor;
75 
77 
79  : PP(nullptr), InitialNumSLocEntries(0),
83 
84  virtual ~PreprocessorLexer() {}
85 
86  virtual void IndirectLex(Token& Result) = 0;
87 
88  /// \brief Return the source location for the next observable location.
89  virtual SourceLocation getSourceLocation() = 0;
90 
91  //===--------------------------------------------------------------------===//
92  // #if directive handling.
93 
94  /// pushConditionalLevel - When we enter a \#if directive, this keeps track of
95  /// what we are currently in for diagnostic emission (e.g. \#if with missing
96  /// \#endif).
97  void pushConditionalLevel(SourceLocation DirectiveStart, bool WasSkipping,
98  bool FoundNonSkip, bool FoundElse) {
100  CI.IfLoc = DirectiveStart;
101  CI.WasSkipping = WasSkipping;
102  CI.FoundNonSkip = FoundNonSkip;
103  CI.FoundElse = FoundElse;
104  ConditionalStack.push_back(CI);
105  }
107  ConditionalStack.push_back(CI);
108  }
109 
110  /// popConditionalLevel - Remove an entry off the top of the conditional
111  /// stack, returning information about it. If the conditional stack is empty,
112  /// this returns true and does not fill in the arguments.
114  if (ConditionalStack.empty())
115  return true;
116  CI = ConditionalStack.pop_back_val();
117  return false;
118  }
119 
120  /// \brief Return the top of the conditional stack.
121  /// \pre This requires that there be a conditional active.
123  assert(!ConditionalStack.empty() && "No conditionals active!");
124  return ConditionalStack.back();
125  }
126 
127  unsigned getConditionalStackDepth() const { return ConditionalStack.size(); }
128 
129 public:
130 
131  //===--------------------------------------------------------------------===//
132  // Misc. lexing methods.
133 
134  /// \brief After the preprocessor has parsed a \#include, lex and
135  /// (potentially) macro expand the filename.
136  ///
137  /// If the sequence parsed is not lexically legal, emit a diagnostic and
138  /// return a result EOD token.
140 
141  /// \brief Inform the lexer whether or not we are currently lexing a
142  /// preprocessor directive.
145  }
146 
147  /// \brief Return true if this lexer is in raw mode or not.
148  bool isLexingRawMode() const { return LexingRawMode; }
149 
150  /// \brief Return the preprocessor object for this lexer.
151  Preprocessor *getPP() const { return PP; }
152 
153  FileID getFileID() const {
154  assert(PP &&
155  "PreprocessorLexer::getFileID() should only be used with a Preprocessor");
156  return FID;
157  }
158 
159  /// \brief Number of SLocEntries before lexing the file.
160  unsigned getInitialNumSLocEntries() const {
161  return InitialNumSLocEntries;
162  }
163 
164  /// getFileEntry - Return the FileEntry corresponding to this FileID. Like
165  /// getFileID(), this only works for lexers with attached preprocessors.
166  const FileEntry *getFileEntry() const;
167 
168  /// \brief Iterator that traverses the current stack of preprocessor
169  /// conditional directives (\#if/\#ifdef/\#ifndef).
172 
174  return ConditionalStack.begin();
175  }
177  return ConditionalStack.end();
178  }
179 };
180 
181 } // end namespace clang
182 
183 #endif
unsigned getInitialNumSLocEntries() const
Number of SLocEntries before lexing the file.
conditional_iterator conditional_begin() const
PPConditionalInfo & peekConditionalLevel()
Return the top of the conditional stack.
unsigned InitialNumSLocEntries
Number of SLocEntries before lexing the file.
void operator=(const PreprocessorLexer &)=delete
void pushConditionalLevel(SourceLocation DirectiveStart, bool WasSkipping, bool FoundNonSkip, bool FoundElse)
pushConditionalLevel - When we enter a #if directive, this keeps track of what we are currently in fo...
Defines the MultipleIncludeOpt interface.
bool ParsingPreprocessorDirective
True when parsing #XXX; turns '\n' into a tok::eod token.
SmallVector< PPConditionalInfo, 4 > ConditionalStack
Information about the set of #if/#ifdef/#ifndef blocks we are currently in.
Token - This structure provides full information about a lexed token.
Definition: Token.h:35
conditional_iterator conditional_end() const
bool popConditionalLevel(PPConditionalInfo &CI)
popConditionalLevel - Remove an entry off the top of the conditional stack, returning information abo...
Implements the simple state machine that the Lexer class uses to detect files subject to the 'multipl...
void setParsingPreprocessorDirective(bool f)
Inform the lexer whether or not we are currently lexing a preprocessor directive. ...
SmallVectorImpl< PPConditionalInfo >::const_iterator conditional_iterator
Iterator that traverses the current stack of preprocessor conditional directives (#if/#ifdef/#ifndef)...
bool FoundNonSkip
True if we have emitted tokens already, and now we're in an #else block or something.
Definition: Token.h:315
const FileID FID
The SourceManager FileID corresponding to the file being lexed.
const FileEntry * getFileEntry() const
getFileEntry - Return the FileEntry corresponding to this FileID.
bool ParsingFilename
True after #include; turns <xx> into a tok::angle_string_literal token.
bool LexingRawMode
True if in raw mode.
void pushConditionalLevel(const PPConditionalInfo &CI)
MultipleIncludeOpt MIOpt
A state machine that detects the #ifndef-wrapping a file idiom for the multiple-include optimization...
Information about the conditional stack (#if directives) currently active.
Definition: Token.h:305
The result type of a method or function.
virtual SourceLocation getSourceLocation()=0
Return the source location for the next observable location.
#define false
Definition: stdbool.h:33
bool WasSkipping
True if this was contained in a skipping directive, e.g., in a "\#if 0" block.
Definition: Token.h:311
Encodes a location in the source.
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:53
unsigned getConditionalStackDepth() const
SourceLocation IfLoc
Location where the conditional started.
Definition: Token.h:307
An opaque identifier used by SourceManager which refers to a source file (MemoryBuffer) along with it...
Preprocessor * getPP() const
Return the preprocessor object for this lexer.
void LexIncludeFilename(Token &Result)
After the preprocessor has parsed a #include, lex and (potentially) macro expand the filename...
bool isLexingRawMode() const
Return true if this lexer is in raw mode or not.
virtual void IndirectLex(Token &Result)=0
bool FoundElse
True if we've seen a #else in this block.
Definition: Token.h:319
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:97