clang  6.0.0svn
TokenLexer.h
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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_LEX_TOKENLEXER_H
15 #define LLVM_CLANG_LEX_TOKENLEXER_H
16 
18 #include "llvm/ADT/ArrayRef.h"
19 
20 namespace clang {
21 
22 class MacroArgs;
23 class MacroInfo;
24 class Preprocessor;
25 class Token;
26 class VAOptExpansionContext;
27 
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.
31 class TokenLexer {
32  friend class Preprocessor;
33 
34  /// Macro - The macro we are expanding from. This is null if expanding a
35  /// token stream.
36  MacroInfo *Macro = nullptr;
37 
38  /// ActualArgs - The actual arguments specified for a function-like macro, or
39  /// null. The TokenLexer owns the pointed-to object.
40  MacroArgs *ActualArgs = nullptr;
41 
42  /// PP - The current preprocessor object we are expanding for.
43  Preprocessor &PP;
44 
45  /// Tokens - This is the pointer to an array of tokens that the macro is
46  /// defined to, with arguments expanded for function-like macros. If this is
47  /// a token stream, these are the tokens we are returning. This points into
48  /// the macro definition we are lexing from, a cache buffer that is owned by
49  /// the preprocessor, or some other buffer that we may or may not own
50  /// (depending on OwnsTokens).
51  /// Note that if it points into Preprocessor's cache buffer, the Preprocessor
52  /// may update the pointer as needed.
53  const Token *Tokens;
54 
55  /// NumTokens - This is the length of the Tokens array.
56  unsigned NumTokens;
57 
58  /// This is the index of the next token that Lex will return.
59  unsigned CurTokenIdx;
60 
61  /// ExpandLocStart/End - The source location range where this macro was
62  /// expanded.
63  SourceLocation ExpandLocStart, ExpandLocEnd;
64 
65  /// \brief Source location pointing at the source location entry chunk that
66  /// was reserved for the current macro expansion.
67  SourceLocation MacroExpansionStart;
68 
69  /// \brief The offset of the macro expansion in the
70  /// "source location address space".
71  unsigned MacroStartSLocOffset;
72 
73  /// \brief Location of the macro definition.
74  SourceLocation MacroDefStart;
75 
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 public:
103  /// Create a TokenLexer for the specified macro with the specified actual
104  /// arguments. Note that this ctor takes ownership of the ActualArgs pointer.
105  /// ILEnd specifies the location of the ')' for a function-like macro or the
106  /// identifier for an object-like macro.
108  MacroArgs *ActualArgs, Preprocessor &pp)
109  : PP(pp), OwnsTokens(false) {
110  Init(Tok, ILEnd, MI, ActualArgs);
111  }
112 
113  /// Create a TokenLexer for the specified token stream. If 'OwnsTokens' is
114  /// specified, this takes ownership of the tokens and delete[]'s them when
115  /// the token lexer is empty.
116  TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion,
117  bool ownsTokens, Preprocessor &pp)
118  : PP(pp), OwnsTokens(false) {
119  Init(TokArray, NumToks, DisableExpansion, ownsTokens);
120  }
121 
122  TokenLexer(const TokenLexer &) = delete;
123  TokenLexer &operator=(const TokenLexer &) = delete;
124  ~TokenLexer() { destroy(); }
125 
126  /// Init - Initialize this TokenLexer to expand from the specified macro
127  /// with the specified argument information. Note that this ctor takes
128  /// ownership of the ActualArgs pointer. ILEnd specifies the location of the
129  /// ')' for a function-like macro or the identifier for an object-like macro.
130  void Init(Token &Tok, SourceLocation ILEnd, MacroInfo *MI,
131  MacroArgs *ActualArgs);
132 
133  /// Init - Initialize this TokenLexer with the specified token stream.
134  /// This does not take ownership of the specified token vector.
135  ///
136  /// DisableExpansion is true when macro expansion of tokens lexed from this
137  /// stream should be disabled.
138  void Init(const Token *TokArray, unsigned NumToks,
139  bool DisableMacroExpansion, bool OwnsTokens);
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 
153 private:
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 CurTokenIdx == NumTokens;
160  }
161 
162  /// Concatenates the next (sub-)sequence of \p Tokens separated by '##'
163  /// starting with LHSTok - stopping when we encounter a token that is neither
164  /// '##' nor preceded by '##'. Places the result back into \p LHSTok and sets
165  /// \p CurIdx to point to the token following the last one that was pasted.
166  ///
167  /// Also performs the MSVC extension wide-literal token pasting involved with:
168  /// \code L #macro-arg. \endcode
169  ///
170  /// \param[in,out] LHSTok - Contains the token to the left of '##' in \p
171  /// Tokens upon entry and will contain the resulting concatenated Token upon
172  /// exit.
173  ///
174  /// \param[in] TokenStream - The stream of Tokens we are lexing from.
175  ///
176  /// \param[in,out] CurIdx - Upon entry, \pTokens[\pCurIdx] must equal '##'
177  /// (with the exception of the MSVC extension mentioned above). Upon exit, it
178  /// is set to the index of the token following the last token that was
179  /// concatenated together.
180  ///
181  /// \returns If this returns true, the caller should immediately return the
182  /// token.
183  bool pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream,
184  unsigned int &CurIdx);
185 
186  /// Calls pasteTokens above, passing in the '*this' object's Tokens and
187  /// CurTokenIdx data members.
188  bool pasteTokens(Token &Tok);
189 
190 
191  /// Takes the tail sequence of tokens within ReplacementToks that represent
192  /// the just expanded __VA_OPT__ tokens (possibly zero tokens) and transforms
193  /// them into a string. \p VCtx is used to determine which token represents
194  /// the first __VA_OPT__ replacement token.
195  ///
196  /// \param[in,out] ReplacementToks - Contains the current Replacement Tokens
197  /// (prior to rescanning and token pasting), the tail end of which represents
198  /// the tokens just expanded through __VA_OPT__ processing. These (sub)
199  /// sequence of tokens are folded into one stringified token.
200  ///
201  /// \param[in] VCtx - contains relevent contextual information about the
202  /// state of the tokens around and including the __VA_OPT__ token, necessary
203  /// for stringification.
204  void stringifyVAOPTContents(SmallVectorImpl<Token> &ReplacementToks,
205  const VAOptExpansionContext &VCtx,
206  SourceLocation VAOPTClosingParenLoc);
207 
208  /// Expand the arguments of a function-like macro so that we can quickly
209  /// return preexpanded tokens from Tokens.
210  void ExpandFunctionArguments();
211 
212  /// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes
213  /// together to form a comment that comments out everything in the current
214  /// macro, other active macros, and anything left on the current physical
215  /// source line of the expanded buffer. Handle this by returning the
216  /// first token on the next line.
217  void HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc);
218 
219  /// \brief If \p loc is a FileID and points inside the current macro
220  /// definition, returns the appropriate source location pointing at the
221  /// macro expansion source location entry.
222  SourceLocation getExpansionLocForMacroDefLoc(SourceLocation loc) const;
223 
224  /// \brief Creates SLocEntries and updates the locations of macro argument
225  /// tokens to their new expanded locations.
226  ///
227  /// \param ArgIdSpellLoc the location of the macro argument id inside the
228  /// macro definition.
229  void updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc,
230  Token *begin_tokens, Token *end_tokens);
231 
232  /// Remove comma ahead of __VA_ARGS__, if present, according to compiler
233  /// dialect settings. Returns true if the comma is removed.
234  bool MaybeRemoveCommaBeforeVaArgs(SmallVectorImpl<Token> &ResultToks,
235  bool HasPasteOperator,
236  MacroInfo *Macro, unsigned MacroArgNo,
237  Preprocessor &PP);
238 
239  void PropagateLineStartLeadingSpaceInfo(Token &Result);
240 };
241 
242 } // namespace clang
243 
244 #endif // LLVM_CLANG_LEX_TOKENLEXER_H
void Init(Token &Tok, SourceLocation ILEnd, MacroInfo *MI, MacroArgs *ActualArgs)
Init - Initialize this TokenLexer to expand from the specified macro with the specified argument info...
Definition: TokenLexer.cpp:39
A class for tracking whether we&#39;re inside a VA_OPT during a traversal of the tokens of a macro during...
TokenLexer & operator=(const TokenLexer &)=delete
Token - This structure provides full information about a lexed token.
Definition: Token.h:35
bool Lex(Token &Tok)
Lex - Lex and return a token from this macro stream.
Definition: TokenLexer.cpp:586
const FormatToken & Tok
TokenLexer - This implements a lexer that returns tokens from a macro body or token stream instead of...
Definition: TokenLexer.h:31
TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion, bool ownsTokens, Preprocessor &pp)
Create a TokenLexer for the specified token stream.
Definition: TokenLexer.h:116
MacroArgs - An instance of this class captures information about the formal arguments specified to a ...
Definition: MacroArgs.h:30
TokenLexer(Token &Tok, SourceLocation ILEnd, MacroInfo *MI, MacroArgs *ActualArgs, Preprocessor &pp)
Create a TokenLexer for the specified macro with the specified actual arguments.
Definition: TokenLexer.h:107
The result type of a method or function.
#define false
Definition: stdbool.h:33
Encodes a location in the source.
Dataflow Directional Tag Classes.
Encapsulates the data about a macro definition (e.g.
Definition: MacroInfo.h:40
unsigned isNextTokenLParen() const
isNextTokenLParen - If the next token lexed will pop this macro off the expansion stack...
Definition: TokenLexer.cpp:889
Defines the clang::SourceLocation class and associated facilities.
bool isParsingPreprocessorDirective() const
isParsingPreprocessorDirective - Return true if we are in the middle of a preprocessor directive...
Definition: TokenLexer.cpp:898
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:127