clang  5.0.0
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/ArrayRef.h"
21 #include "llvm/ADT/SmallVector.h"
22 
23 namespace clang {
24 
25 class FileEntry;
26 class Preprocessor;
27 
29  virtual void anchor();
30 protected:
31  Preprocessor *PP; // Preprocessor object controlling lexing.
32 
33  /// The SourceManager FileID corresponding to the file being lexed.
34  const FileID FID;
35 
36  /// \brief Number of SLocEntries before lexing the file.
38 
39  //===--------------------------------------------------------------------===//
40  // Context-specific lexing flags set by the preprocessor.
41  //===--------------------------------------------------------------------===//
42 
43  /// \brief True when parsing \#XXX; turns '\\n' into a tok::eod token.
45 
46  /// \brief True after \#include; turns <xx> into a tok::angle_string_literal
47  /// token.
49 
50  /// \brief True if in raw mode.
51  ///
52  /// Raw mode disables interpretation of tokens and is a far faster mode to
53  /// lex in than non-raw-mode. This flag:
54  /// 1. If EOF of the current lexer is found, the include stack isn't popped.
55  /// 2. Identifier information is not looked up for identifier tokens. As an
56  /// effect of this, implicit macro expansion is naturally disabled.
57  /// 3. "#" tokens at the start of a line are treated as normal tokens, not
58  /// implicitly transformed by the lexer.
59  /// 4. All diagnostic messages are disabled.
60  /// 5. No callbacks are made into the preprocessor.
61  ///
62  /// Note that in raw mode that the PP pointer may be null.
64 
65  /// \brief A state machine that detects the \#ifndef-wrapping a file
66  /// idiom for the multiple-include optimization.
68 
69  /// \brief Information about the set of \#if/\#ifdef/\#ifndef blocks
70  /// we are currently in.
72 
73  PreprocessorLexer(const PreprocessorLexer &) = delete;
74  void operator=(const PreprocessorLexer &) = delete;
75  friend class Preprocessor;
76 
78 
80  : PP(nullptr), InitialNumSLocEntries(0),
84 
85  virtual ~PreprocessorLexer() {}
86 
87  virtual void IndirectLex(Token& Result) = 0;
88 
89  /// \brief Return the source location for the next observable location.
90  virtual SourceLocation getSourceLocation() = 0;
91 
92  //===--------------------------------------------------------------------===//
93  // #if directive handling.
94 
95  /// pushConditionalLevel - When we enter a \#if directive, this keeps track of
96  /// what we are currently in for diagnostic emission (e.g. \#if with missing
97  /// \#endif).
98  void pushConditionalLevel(SourceLocation DirectiveStart, bool WasSkipping,
99  bool FoundNonSkip, bool FoundElse) {
101  CI.IfLoc = DirectiveStart;
102  CI.WasSkipping = WasSkipping;
103  CI.FoundNonSkip = FoundNonSkip;
104  CI.FoundElse = FoundElse;
105  ConditionalStack.push_back(CI);
106  }
108  ConditionalStack.push_back(CI);
109  }
110 
111  /// popConditionalLevel - Remove an entry off the top of the conditional
112  /// stack, returning information about it. If the conditional stack is empty,
113  /// this returns true and does not fill in the arguments.
115  if (ConditionalStack.empty())
116  return true;
117  CI = ConditionalStack.pop_back_val();
118  return false;
119  }
120 
121  /// \brief Return the top of the conditional stack.
122  /// \pre This requires that there be a conditional active.
124  assert(!ConditionalStack.empty() && "No conditionals active!");
125  return ConditionalStack.back();
126  }
127 
128  unsigned getConditionalStackDepth() const { return ConditionalStack.size(); }
129 
130 public:
131 
132  //===--------------------------------------------------------------------===//
133  // Misc. lexing methods.
134 
135  /// \brief After the preprocessor has parsed a \#include, lex and
136  /// (potentially) macro expand the filename.
137  ///
138  /// If the sequence parsed is not lexically legal, emit a diagnostic and
139  /// return a result EOD token.
141 
142  /// \brief Inform the lexer whether or not we are currently lexing a
143  /// preprocessor directive.
146  }
147 
148  /// \brief Return true if this lexer is in raw mode or not.
149  bool isLexingRawMode() const { return LexingRawMode; }
150 
151  /// \brief Return the preprocessor object for this lexer.
152  Preprocessor *getPP() const { return PP; }
153 
154  FileID getFileID() const {
155  assert(PP &&
156  "PreprocessorLexer::getFileID() should only be used with a Preprocessor");
157  return FID;
158  }
159 
160  /// \brief Number of SLocEntries before lexing the file.
161  unsigned getInitialNumSLocEntries() const {
162  return InitialNumSLocEntries;
163  }
164 
165  /// getFileEntry - Return the FileEntry corresponding to this FileID. Like
166  /// getFileID(), this only works for lexers with attached preprocessors.
167  const FileEntry *getFileEntry() const;
168 
169  /// \brief Iterator that traverses the current stack of preprocessor
170  /// conditional directives (\#if/\#ifdef/\#ifndef).
173 
175  return ConditionalStack.begin();
176  }
178  return ConditionalStack.end();
179  }
180 
182  ConditionalStack.clear();
183  ConditionalStack.append(CL.begin(), CL.end());
184  }
185 };
186 
187 } // end namespace clang
188 
189 #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:323
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:313
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:319
Encodes a location in the source.
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:59
unsigned getConditionalStackDepth() const
SourceLocation IfLoc
Location where the conditional started.
Definition: Token.h:315
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 setConditionalLevels(ArrayRef< PPConditionalInfo > CL)
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:327
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:98