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"
18 #include "llvm/ADT/ArrayRef.h"
26 class VAOptExpansionContext;
28 /// TokenLexer - This implements a lexer that returns tokens from a macro body
29 /// or token stream instead of lexing from a character buffer. This is used for
30 /// macro expansion and _Pragma handling, for example.
32 friend class Preprocessor;
34 /// The macro we are expanding from. This is null if expanding a token stream.
35 MacroInfo *Macro = nullptr;
37 /// The actual arguments specified for a function-like macro, or null. The
38 /// TokenLexer owns the pointed-to object.
39 MacroArgs *ActualArgs = nullptr;
41 /// The current preprocessor object we are expanding for.
44 /// This is the pointer to an array of tokens that the macro is
45 /// defined to, with arguments expanded for function-like macros. If this is
46 /// a token stream, these are the tokens we are returning. This points into
47 /// the macro definition we are lexing from, a cache buffer that is owned by
48 /// the preprocessor, or some other buffer that we may or may not own
49 /// (depending on OwnsTokens).
50 /// Note that if it points into Preprocessor's cache buffer, the Preprocessor
51 /// may update the pointer as needed.
54 /// This is the length of the Tokens array.
57 /// This is the index of the next token that Lex will return.
60 /// The source location range where this macro was expanded.
61 SourceLocation ExpandLocStart, ExpandLocEnd;
63 /// Source location pointing at the source location entry chunk that
64 /// was reserved for the current macro expansion.
65 SourceLocation MacroExpansionStart;
67 /// The offset of the macro expansion in the
68 /// "source location address space".
69 unsigned MacroStartSLocOffset;
71 /// Location of the macro definition.
72 SourceLocation MacroDefStart;
74 /// Length of the macro definition.
75 unsigned MacroDefLength;
77 /// Lexical information about the expansion point of the macro: the identifier
78 /// that the macro expanded from had these properties.
79 bool AtStartOfLine : 1;
80 bool HasLeadingSpace : 1;
82 // When this is true, the next token appended to the
83 // output list during function argument expansion will get a leading space,
84 // regardless of whether it had one to begin with or not. This is used for
85 // placemarker support. If still true after function argument expansion, the
86 // leading space will be applied to the first token following the macro
88 bool NextTokGetsSpace : 1;
90 /// This is true if this TokenLexer allocated the Tokens
91 /// array, and thus needs to free it when destroyed. For simple object-like
92 /// macros (for example) we just point into the token buffer of the macro
93 /// definition, we don't make a copy of it.
96 /// This is true when tokens lexed from the TokenLexer
97 /// should not be subject to further macro expansion.
98 bool DisableMacroExpansion : 1;
101 /// Create a TokenLexer for the specified macro with the specified actual
102 /// arguments. Note that this ctor takes ownership of the ActualArgs pointer.
103 /// ILEnd specifies the location of the ')' for a function-like macro or the
104 /// identifier for an object-like macro.
105 TokenLexer(Token &Tok, SourceLocation ILEnd, MacroInfo *MI,
106 MacroArgs *ActualArgs, Preprocessor &pp)
107 : PP(pp), OwnsTokens(false) {
108 Init(Tok, ILEnd, MI, ActualArgs);
111 /// Create a TokenLexer for the specified token stream. If 'OwnsTokens' is
112 /// specified, this takes ownership of the tokens and delete[]'s them when
113 /// the token lexer is empty.
114 TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion,
115 bool ownsTokens, Preprocessor &pp)
116 : PP(pp), OwnsTokens(false) {
117 Init(TokArray, NumToks, DisableExpansion, ownsTokens);
120 TokenLexer(const TokenLexer &) = delete;
121 TokenLexer &operator=(const TokenLexer &) = delete;
122 ~TokenLexer() { destroy(); }
124 /// Initialize this TokenLexer to expand from the specified macro
125 /// with the specified argument information. Note that this ctor takes
126 /// ownership of the ActualArgs pointer. ILEnd specifies the location of the
127 /// ')' for a function-like macro or the identifier for an object-like macro.
128 void Init(Token &Tok, SourceLocation ELEnd, MacroInfo *MI,
131 /// 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 /// If the next token lexed will pop this macro off the
140 /// expansion stack, return 2. If the next unexpanded token is a '(', return
141 /// 1, otherwise return 0.
142 unsigned isNextTokenLParen() const;
144 /// Lex and return a token from this macro stream.
145 bool Lex(Token &Tok);
147 /// isParsingPreprocessorDirective - Return true if we are in the middle of a
148 /// preprocessor directive.
149 bool isParsingPreprocessorDirective() const;
154 /// Return true if the next lex call will pop this macro off the include
156 bool isAtEnd() const {
157 return CurTokenIdx == NumTokens;
160 /// Concatenates the next (sub-)sequence of \p Tokens separated by '##'
161 /// starting with LHSTok - stopping when we encounter a token that is neither
162 /// '##' nor preceded by '##'. Places the result back into \p LHSTok and sets
163 /// \p CurIdx to point to the token following the last one that was pasted.
165 /// Also performs the MSVC extension wide-literal token pasting involved with:
166 /// \code L #macro-arg. \endcode
168 /// \param[in,out] LHSTok - Contains the token to the left of '##' in \p
169 /// Tokens upon entry and will contain the resulting concatenated Token upon
172 /// \param[in] TokenStream - The stream of Tokens we are lexing from.
174 /// \param[in,out] CurIdx - Upon entry, \pTokens[\pCurIdx] must equal '##'
175 /// (with the exception of the MSVC extension mentioned above). Upon exit, it
176 /// is set to the index of the token following the last token that was
177 /// concatenated together.
179 /// \returns If this returns true, the caller should immediately return the
181 bool pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream,
182 unsigned int &CurIdx);
184 /// Calls pasteTokens above, passing in the '*this' object's Tokens and
185 /// CurTokenIdx data members.
186 bool pasteTokens(Token &Tok);
189 /// Takes the tail sequence of tokens within ReplacementToks that represent
190 /// the just expanded __VA_OPT__ tokens (possibly zero tokens) and transforms
191 /// them into a string. \p VCtx is used to determine which token represents
192 /// the first __VA_OPT__ replacement token.
194 /// \param[in,out] ResultToks - Contains the current Replacement Tokens
195 /// (prior to rescanning and token pasting), the tail end of which represents
196 /// the tokens just expanded through __VA_OPT__ processing. These (sub)
197 /// sequence of tokens are folded into one stringified token.
199 /// \param[in] VCtx - contains relevant contextual information about the
200 /// state of the tokens around and including the __VA_OPT__ token, necessary
201 /// for stringification.
202 void stringifyVAOPTContents(SmallVectorImpl<Token> &ResultToks,
203 const VAOptExpansionContext &VCtx,
204 SourceLocation VAOPTClosingParenLoc);
206 /// Expand the arguments of a function-like macro so that we can quickly
207 /// return preexpanded tokens from Tokens.
208 void ExpandFunctionArguments();
210 /// In microsoft compatibility mode, /##/ pastes
211 /// together to form a comment that comments out everything in the current
212 /// macro, other active macros, and anything left on the current physical
213 /// source line of the expanded buffer. Handle this by returning the
214 /// first token on the next line.
215 void HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc);
217 /// If \p loc is a FileID and points inside the current macro
218 /// definition, returns the appropriate source location pointing at the
219 /// macro expansion source location entry.
220 SourceLocation getExpansionLocForMacroDefLoc(SourceLocation loc) const;
222 /// Creates SLocEntries and updates the locations of macro argument
223 /// tokens to their new expanded locations.
225 /// \param ArgIdSpellLoc the location of the macro argument id inside the
226 /// macro definition.
227 void updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc,
228 Token *begin_tokens, Token *end_tokens);
230 /// Remove comma ahead of __VA_ARGS__, if present, according to compiler
231 /// dialect settings. Returns true if the comma is removed.
232 bool MaybeRemoveCommaBeforeVaArgs(SmallVectorImpl<Token> &ResultToks,
233 bool HasPasteOperator,
234 MacroInfo *Macro, unsigned MacroArgNo,
237 void PropagateLineStartLeadingSpaceInfo(Token &Result);
242 #endif // LLVM_CLANG_LEX_TOKENLEXER_H