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_LEX_TOKENLEXER_H
15 #define LLVM_CLANG_LEX_TOKENLEXER_H
17 #include "clang/Basic/SourceLocation.h"
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.
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 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.
52 friend class Preprocessor;
54 /// NumTokens - This is the length of the Tokens array.
58 /// CurToken - This is the next token that Lex will return.
62 /// ExpandLocStart/End - The source location range where this macro was
64 SourceLocation ExpandLocStart, ExpandLocEnd;
66 /// \brief Source location pointing at the source location entry chunk that
67 /// was reserved for the current macro expansion.
68 SourceLocation MacroExpansionStart;
70 /// \brief The offset of the macro expansion in the
71 /// "source location address space".
72 unsigned MacroStartSLocOffset;
74 /// \brief Location of the macro definition.
75 SourceLocation MacroDefStart;
76 /// \brief Length of the macro definition.
77 unsigned MacroDefLength;
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;
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
90 bool NextTokGetsSpace : 1;
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.
98 /// DisableMacroExpansion - This is true when tokens lexed from the TokenLexer
99 /// should not be subject to further macro expansion.
100 bool DisableMacroExpansion : 1;
102 TokenLexer(const TokenLexer &) LLVM_DELETED_FUNCTION;
103 void operator=(const TokenLexer &) LLVM_DELETED_FUNCTION;
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);
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);
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);
131 /// Init - Initialize this TokenLexer with the specified token stream.
132 /// This does not take ownership of the specified token vector.
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);
139 ~TokenLexer() { destroy(); }
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;
146 /// Lex - Lex and return a token from this macro stream.
147 bool Lex(Token &Tok);
149 /// isParsingPreprocessorDirective - Return true if we are in the middle of a
150 /// preprocessor directive.
151 bool isParsingPreprocessorDirective() const;
156 /// isAtEnd - Return true if the next lex call will pop this macro off the
158 bool isAtEnd() const {
159 return CurToken == NumTokens;
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
167 bool PasteTokens(Token &Tok);
169 /// Expand the arguments of a function-like macro so that we can quickly
170 /// return preexpanded tokens from Tokens.
171 void ExpandFunctionArguments();
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);
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;
185 /// \brief Creates SLocEntries and updates the locations of macro argument
186 /// tokens to their new expanded locations.
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);
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,
200 void PropagateLineStartLeadingSpaceInfo(Token &Result);
203 } // end namespace clang