1 //===--- TokenLexer.h - Lex from a token buffer -----------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the TokenLexer interface.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_TOKENLEXER_H
15 #define LLVM_CLANG_TOKENLEXER_H
17 #include "clang/Basic/SourceLocation.h"
25 /// TokenLexer - This implements a lexer that returns token 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.
30 /// Macro - The macro we are expanding from. This is null if expanding a
35 /// ActualArgs - The actual arguments specified for a function-like macro, or
36 /// null. The TokenLexer owns the pointed-to object.
37 MacroArgs *ActualArgs;
39 /// PP - The current preprocessor object we are expanding for.
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 scratch buffer allocated from
47 /// the preprocessor's bump pointer allocator, or some other buffer that we
48 /// may or may not own (depending on OwnsTokens).
51 /// NumTokens - This is the length of the Tokens array.
55 /// CurToken - This is the next token that Lex will return.
59 /// InstantiateLocStart/End - The source location range where this macro was
61 SourceLocation InstantiateLocStart, InstantiateLocEnd;
63 /// Lexical information about the expansion point of the macro: the identifier
64 /// that the macro expanded from had these properties.
65 bool AtStartOfLine : 1;
66 bool HasLeadingSpace : 1;
68 /// OwnsTokens - This is true if this TokenLexer allocated the Tokens
69 /// array, and thus needs to free it when destroyed. For simple object-like
70 /// macros (for example) we just point into the token buffer of the macro
71 /// definition, we don't make a copy of it.
74 /// DisableMacroExpansion - This is true when tokens lexed from the TokenLexer
75 /// should not be subject to further macro expansion.
76 bool DisableMacroExpansion : 1;
78 TokenLexer(const TokenLexer&); // DO NOT IMPLEMENT
79 void operator=(const TokenLexer&); // DO NOT IMPLEMENT
81 /// Create a TokenLexer for the specified macro with the specified actual
82 /// arguments. Note that this ctor takes ownership of the ActualArgs pointer.
83 /// ILEnd specifies the location of the ')' for a function-like macro or the
84 /// identifier for an object-like macro.
85 TokenLexer(Token &Tok, SourceLocation ILEnd, MacroArgs *ActualArgs,
87 : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) {
88 Init(Tok, ILEnd, ActualArgs);
91 /// Init - Initialize this TokenLexer to expand from the specified macro
92 /// with the specified argument information. Note that this ctor takes
93 /// ownership of the ActualArgs pointer. ILEnd specifies the location of the
94 /// ')' for a function-like macro or the identifier for an object-like macro.
95 void Init(Token &Tok, SourceLocation ILEnd, MacroArgs *ActualArgs);
97 /// Create a TokenLexer for the specified token stream. If 'OwnsTokens' is
98 /// specified, this takes ownership of the tokens and delete[]'s them when
99 /// the token lexer is empty.
100 TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion,
101 bool ownsTokens, Preprocessor &pp)
102 : Macro(0), ActualArgs(0), PP(pp), OwnsTokens(false) {
103 Init(TokArray, NumToks, DisableExpansion, ownsTokens);
106 /// Init - Initialize this TokenLexer with the specified token stream.
107 /// This does not take ownership of the specified token vector.
109 /// DisableExpansion is true when macro expansion of tokens lexed from this
110 /// stream should be disabled.
111 void Init(const Token *TokArray, unsigned NumToks,
112 bool DisableMacroExpansion, bool OwnsTokens);
114 ~TokenLexer() { destroy(); }
116 /// isNextTokenLParen - If the next token lexed will pop this macro off the
117 /// expansion stack, return 2. If the next unexpanded token is a '(', return
118 /// 1, otherwise return 0.
119 unsigned isNextTokenLParen() const;
121 /// Lex - Lex and return a token from this macro stream.
122 void Lex(Token &Tok);
124 /// isParsingPreprocessorDirective - Return true if we are in the middle of a
125 /// preprocessor directive.
126 bool isParsingPreprocessorDirective() const;
131 /// isAtEnd - Return true if the next lex call will pop this macro off the
133 bool isAtEnd() const {
134 return CurToken == NumTokens;
137 /// PasteTokens - Tok is the LHS of a ## operator, and CurToken is the ##
138 /// operator. Read the ## and RHS, and paste the LHS/RHS together. If there
139 /// are is another ## after it, chomp it iteratively. Return the result as
140 /// Tok. If this returns true, the caller should immediately return the
142 bool PasteTokens(Token &Tok);
144 /// Expand the arguments of a function-like macro so that we can quickly
145 /// return preexpanded tokens from Tokens.
146 void ExpandFunctionArguments();
148 /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes
149 /// together to form a comment that comments out everything in the current
150 /// macro, other active macros, and anything left on the current physical
151 /// source line of the instantiated buffer. Handle this by returning the
152 /// first token on the next line.
153 void HandleMicrosoftCommentPaste(Token &Tok);
156 } // end namespace clang