PreprocessorLexer.h revision 74d15dfd183b2082e8a5d4dfbf66bd861b220901 
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//  This file defines the PreprocessorLexer interface.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_PreprocessorLexer_H
15#define LLVM_CLANG_PreprocessorLexer_H
16
17#include "clang/Lex/MultipleIncludeOpt.h"
18#include "clang/Lex/Token.h"
19#include <vector>
20#include <string>
21
22namespace clang {
23
24class Preprocessor;
25
26class PreprocessorLexer {
27protected:
28  Preprocessor *PP;              // Preprocessor object controlling lexing.
29
30  /// The SourceManager fileID corresponding to the file being lexed.
31  const unsigned FileID;
32
33  //===--------------------------------------------------------------------===//
34  // Context-specific lexing flags set by the preprocessor.
35  //===--------------------------------------------------------------------===//
36
37  /// ParsingPreprocessorDirective - This is true when parsing #XXX.  This turns
38  /// '\n' into a tok::eom token.
39  bool ParsingPreprocessorDirective;
40
41  /// ParsingFilename - True after #include: this turns <xx> into a
42  /// tok::angle_string_literal token.
43  bool ParsingFilename;
44
45  /// LexingRawMode - True if in raw mode:  This flag disables interpretation of
46  /// tokens and is a far faster mode to lex in than non-raw-mode.  This flag:
47  ///  1. If EOF of the current lexer is found, the include stack isn't popped.
48  ///  2. Identifier information is not looked up for identifier tokens.  As an
49  ///     effect of this, implicit macro expansion is naturally disabled.
50  ///  3. "#" tokens at the start of a line are treated as normal tokens, not
51  ///     implicitly transformed by the lexer.
52  ///  4. All diagnostic messages are disabled.
53  ///  5. No callbacks are made into the preprocessor.
54  ///
55  /// Note that in raw mode that the PP pointer may be null.
56  bool LexingRawMode;
57
58  /// MIOpt - This is a state machine that detects the #ifndef-wrapping a file
59  /// idiom for the multiple-include optimization.
60  MultipleIncludeOpt MIOpt;
61
62  /// ConditionalStack - Information about the set of #if/#ifdef/#ifndef blocks
63  /// we are currently in.
64  std::vector<PPConditionalInfo> ConditionalStack;
65
66  PreprocessorLexer(const PreprocessorLexer&);          // DO NOT IMPLEMENT
67  void operator=(const PreprocessorLexer&); // DO NOT IMPLEMENT
68  friend class Preprocessor;
69
70  PreprocessorLexer(Preprocessor* pp, SourceLocation L);
71
72  PreprocessorLexer()
73    : PP(0), FileID(0),
74      ParsingPreprocessorDirective(false),
75      ParsingFilename(false),
76      LexingRawMode(false) {}
77
78  virtual ~PreprocessorLexer();
79
80  virtual void IndirectLex(Token& Result) = 0;
81
82  /// Diag - Forwarding function for diagnostics.  This translate a source
83  /// position in the current buffer into a SourceLocation object for rendering.
84  void Diag(SourceLocation Loc, unsigned DiagID,
85            const std::string &Msg = std::string()) const;
86
87  //===--------------------------------------------------------------------===//
88  // #if directive handling.
89
90  /// pushConditionalLevel - When we enter a #if directive, this keeps track of
91  /// what we are currently in for diagnostic emission (e.g. #if with missing
92  /// #endif).
93  void pushConditionalLevel(SourceLocation DirectiveStart, bool WasSkipping,
94                            bool FoundNonSkip, bool FoundElse) {
95    PPConditionalInfo CI;
96    CI.IfLoc = DirectiveStart;
97    CI.WasSkipping = WasSkipping;
98    CI.FoundNonSkip = FoundNonSkip;
99    CI.FoundElse = FoundElse;
100    ConditionalStack.push_back(CI);
101  }
102  void pushConditionalLevel(const PPConditionalInfo &CI) {
103    ConditionalStack.push_back(CI);
104  }
105
106  /// popConditionalLevel - Remove an entry off the top of the conditional
107  /// stack, returning information about it.  If the conditional stack is empty,
108  /// this returns true and does not fill in the arguments.
109  bool popConditionalLevel(PPConditionalInfo &CI) {
110    if (ConditionalStack.empty()) return true;
111    CI = ConditionalStack.back();
112    ConditionalStack.pop_back();
113    return false;
114  }
115
116  /// peekConditionalLevel - Return the top of the conditional stack.  This
117  /// requires that there be a conditional active.
118  PPConditionalInfo &peekConditionalLevel() {
119    assert(!ConditionalStack.empty() && "No conditionals active!");
120    return ConditionalStack.back();
121  }
122
123  unsigned getConditionalStackDepth() const { return ConditionalStack.size(); }
124
125  //===--------------------------------------------------------------------===//
126  // Misc. lexing methods.
127
128  /// LexIncludeFilename - After the preprocessor has parsed a #include, lex and
129  /// (potentially) macro expand the filename.  If the sequence parsed is not
130  /// lexically legal, emit a diagnostic and return a result EOM token.
131  void LexIncludeFilename(Token &Result);
132
133public:
134
135  /// isLexingRawMode - Return true if this lexer is in raw mode or not.
136  bool isLexingRawMode() const { return LexingRawMode; }
137
138  /// getPP - Return the preprocessor object for this lexer.
139  Preprocessor *getPP() const { return PP; }
140
141  unsigned getFileID() const {
142    assert(PP &&
143      "PreprocessorLexer::getFileID() should only be used with a Preprocessor");
144    return FileID;
145  }
146};
147
148}  // end namespace clang
149
150#endif
151