1//===--- TokenLexer.h - Lex from a token buffer -----------------*- 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 TokenLexer interface.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_TOKENLEXER_H
15#define LLVM_CLANG_TOKENLEXER_H
16
17#include "clang/Basic/SourceLocation.h"
18
19namespace clang {
20  class MacroInfo;
21  class Preprocessor;
22  class Token;
23  class MacroArgs;
24
25/// TokenLexer - This implements a lexer that returns tokens from a macro body
26/// or token stream instead of lexing from a character buffer.  This is used for
27/// macro expansion and _Pragma handling, for example.
28///
29class TokenLexer {
30  /// Macro - The macro we are expanding from.  This is null if expanding a
31  /// token stream.
32  ///
33  MacroInfo *Macro;
34
35  /// ActualArgs - The actual arguments specified for a function-like macro, or
36  /// null.  The TokenLexer owns the pointed-to object.
37  MacroArgs *ActualArgs;
38
39  /// PP - The current preprocessor object we are expanding for.
40  ///
41  Preprocessor &PP;
42
43  /// Tokens - This is the pointer to an array of tokens that the macro is
44  /// defined to, with arguments expanded for function-like macros.  If this is
45  /// a token stream, these are the tokens we are returning.  This points into
46  /// the macro definition we are lexing from, a cache buffer that is owned by
47  /// the preprocessor, or some other buffer that we may or may not own
48  /// (depending on OwnsTokens).
49  /// Note that if it points into Preprocessor's cache buffer, the Preprocessor
50  /// may update the pointer as needed.
51  const Token *Tokens;
52  friend class Preprocessor;
53
54  /// NumTokens - This is the length of the Tokens array.
55  ///
56  unsigned NumTokens;
57
58  /// CurToken - This is the next token that Lex will return.
59  ///
60  unsigned CurToken;
61
62  /// ExpandLocStart/End - The source location range where this macro was
63  /// expanded.
64  SourceLocation ExpandLocStart, ExpandLocEnd;
65
66  /// \brief Source location pointing at the source location entry chunk that
67  /// was reserved for the current macro expansion.
68  SourceLocation MacroExpansionStart;
69
70  /// \brief The offset of the macro expansion in the
71  /// "source location address space".
72  unsigned MacroStartSLocOffset;
73
74  /// \brief Location of the macro definition.
75  SourceLocation MacroDefStart;
76  /// \brief Length of the macro definition.
77  unsigned MacroDefLength;
78
79  /// Lexical information about the expansion point of the macro: the identifier
80  /// that the macro expanded from had these properties.
81  bool AtStartOfLine : 1;
82  bool HasLeadingSpace : 1;
83
84  // NextTokGetsSpace - When this is true, the next token appended to the
85  // output list during function argument expansion will get a leading space,
86  // regardless of whether it had one to begin with or not. This is used for
87  // placemarker support. If still true after function argument expansion, the
88  // leading space will be applied to the first token following the macro
89  // expansion.
90  bool NextTokGetsSpace : 1;
91
92  /// OwnsTokens - This is true if this TokenLexer allocated the Tokens
93  /// array, and thus needs to free it when destroyed.  For simple object-like
94  /// macros (for example) we just point into the token buffer of the macro
95  /// definition, we don't make a copy of it.
96  bool OwnsTokens : 1;
97
98  /// DisableMacroExpansion - This is true when tokens lexed from the TokenLexer
99  /// should not be subject to further macro expansion.
100  bool DisableMacroExpansion : 1;
101
102  TokenLexer(const TokenLexer &) LLVM_DELETED_FUNCTION;
103  void operator=(const TokenLexer &) LLVM_DELETED_FUNCTION;
104public:
105  /// Create a TokenLexer for the specified macro with the specified actual
106  /// arguments.  Note that this ctor takes ownership of the ActualArgs pointer.
107  /// ILEnd specifies the location of the ')' for a function-like macro or the
108  /// identifier for an object-like macro.
109  TokenLexer(Token &Tok, SourceLocation ILEnd, MacroInfo *MI,
110             MacroArgs *ActualArgs, Preprocessor &pp)
111    : Macro(nullptr), ActualArgs(nullptr), PP(pp), OwnsTokens(false) {
112    Init(Tok, ILEnd, MI, ActualArgs);
113  }
114
115  /// Init - Initialize this TokenLexer to expand from the specified macro
116  /// with the specified argument information.  Note that this ctor takes
117  /// ownership of the ActualArgs pointer.  ILEnd specifies the location of the
118  /// ')' for a function-like macro or the identifier for an object-like macro.
119  void Init(Token &Tok, SourceLocation ILEnd, MacroInfo *MI,
120            MacroArgs *ActualArgs);
121
122  /// Create a TokenLexer for the specified token stream.  If 'OwnsTokens' is
123  /// specified, this takes ownership of the tokens and delete[]'s them when
124  /// the token lexer is empty.
125  TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion,
126             bool ownsTokens, Preprocessor &pp)
127    : Macro(nullptr), ActualArgs(nullptr), PP(pp), OwnsTokens(false) {
128    Init(TokArray, NumToks, DisableExpansion, ownsTokens);
129  }
130
131  /// Init - Initialize this TokenLexer with the specified token stream.
132  /// This does not take ownership of the specified token vector.
133  ///
134  /// DisableExpansion is true when macro expansion of tokens lexed from this
135  /// stream should be disabled.
136  void Init(const Token *TokArray, unsigned NumToks,
137            bool DisableMacroExpansion, bool OwnsTokens);
138
139  ~TokenLexer() { destroy(); }
140
141  /// isNextTokenLParen - If the next token lexed will pop this macro off the
142  /// expansion stack, return 2.  If the next unexpanded token is a '(', return
143  /// 1, otherwise return 0.
144  unsigned isNextTokenLParen() const;
145
146  /// Lex - Lex and return a token from this macro stream.
147  bool Lex(Token &Tok);
148
149  /// isParsingPreprocessorDirective - Return true if we are in the middle of a
150  /// preprocessor directive.
151  bool isParsingPreprocessorDirective() const;
152
153private:
154  void destroy();
155
156  /// isAtEnd - Return true if the next lex call will pop this macro off the
157  /// include stack.
158  bool isAtEnd() const {
159    return CurToken == NumTokens;
160  }
161
162  /// PasteTokens - Tok is the LHS of a ## operator, and CurToken is the ##
163  /// operator.  Read the ## and RHS, and paste the LHS/RHS together.  If there
164  /// are is another ## after it, chomp it iteratively.  Return the result as
165  /// Tok.  If this returns true, the caller should immediately return the
166  /// token.
167  bool PasteTokens(Token &Tok);
168
169  /// Expand the arguments of a function-like macro so that we can quickly
170  /// return preexpanded tokens from Tokens.
171  void ExpandFunctionArguments();
172
173  /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes
174  /// together to form a comment that comments out everything in the current
175  /// macro, other active macros, and anything left on the current physical
176  /// source line of the expanded buffer.  Handle this by returning the
177  /// first token on the next line.
178  void HandleMicrosoftCommentPaste(Token &Tok);
179
180  /// \brief If \p loc is a FileID and points inside the current macro
181  /// definition, returns the appropriate source location pointing at the
182  /// macro expansion source location entry.
183  SourceLocation getExpansionLocForMacroDefLoc(SourceLocation loc) const;
184
185  /// \brief Creates SLocEntries and updates the locations of macro argument
186  /// tokens to their new expanded locations.
187  ///
188  /// \param ArgIdSpellLoc the location of the macro argument id inside the
189  /// macro definition.
190  void updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc,
191                                  Token *begin_tokens, Token *end_tokens);
192
193  /// Remove comma ahead of __VA_ARGS__, if present, according to compiler
194  /// dialect settings.  Returns true if the comma is removed.
195  bool MaybeRemoveCommaBeforeVaArgs(SmallVectorImpl<Token> &ResultToks,
196                                    bool HasPasteOperator,
197                                    MacroInfo *Macro, unsigned MacroArgNo,
198                                    Preprocessor &PP);
199
200  void PropagateLineStartLeadingSpaceInfo(Token &Result);
201};
202
203}  // end namespace clang
204
205#endif
206