clang  8.0.0svn
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  /// The macro we are expanding from. This is null if expanding a token stream.
35  MacroInfo *Macro = nullptr;
36 
37  /// The actual arguments specified for a function-like macro, or null. The
38  /// TokenLexer owns the pointed-to object.
39  MacroArgs *ActualArgs = nullptr;
40 
41  /// The current preprocessor object we are expanding for.
42  Preprocessor &PP;
43 
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.
52  const Token *Tokens;
53 
54  /// This is the length of the Tokens array.
55  unsigned NumTokens;
56 
57  /// This is the index of the next token that Lex will return.
58  unsigned CurTokenIdx;
59 
60  /// The source location range where this macro was expanded.
61  SourceLocation ExpandLocStart, ExpandLocEnd;
62 
63  /// Source location pointing at the source location entry chunk that
64  /// was reserved for the current macro expansion.
65  SourceLocation MacroExpansionStart;
66 
67  /// The offset of the macro expansion in the
68  /// "source location address space".
69  unsigned MacroStartSLocOffset;
70 
71  /// Location of the macro definition.
72  SourceLocation MacroDefStart;
73 
74  /// Length of the macro definition.
75  unsigned MacroDefLength;
76 
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;
81 
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
87  // expansion.
88  bool NextTokGetsSpace : 1;
89 
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.
94  bool OwnsTokens : 1;
95 
96  /// This is true when tokens lexed from the TokenLexer
97  /// should not be subject to further macro expansion.
98  bool DisableMacroExpansion : 1;
99 
100 public:
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.
106  MacroArgs *ActualArgs, Preprocessor &pp)
107  : PP(pp), OwnsTokens(false) {
108  Init(Tok, ILEnd, MI, ActualArgs);
109  }
110 
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);
118  }
119 
120  TokenLexer(const TokenLexer &) = delete;
121  TokenLexer &operator=(const TokenLexer &) = delete;
122  ~TokenLexer() { destroy(); }
123 
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,
129  MacroArgs *Actuals);
130 
131  /// 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  /// 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;
143 
144  /// Lex and return a token from this macro stream.
145  bool Lex(Token &Tok);
146 
147  /// isParsingPreprocessorDirective - Return true if we are in the middle of a
148  /// preprocessor directive.
149  bool isParsingPreprocessorDirective() const;
150 
151 private:
152  void destroy();
153 
154  /// Return true if the next lex call will pop this macro off the include
155  /// stack.
156  bool isAtEnd() const {
157  return CurTokenIdx == NumTokens;
158  }
159 
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.
164  ///
165  /// Also performs the MSVC extension wide-literal token pasting involved with:
166  /// \code L #macro-arg. \endcode
167  ///
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
170  /// exit.
171  ///
172  /// \param[in] TokenStream - The stream of Tokens we are lexing from.
173  ///
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.
178  ///
179  /// \returns If this returns true, the caller should immediately return the
180  /// token.
181  bool pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream,
182  unsigned int &CurIdx);
183 
184  /// Calls pasteTokens above, passing in the '*this' object's Tokens and
185  /// CurTokenIdx data members.
186  bool pasteTokens(Token &Tok);
187 
188 
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.
193  ///
194  /// \param[in,out] ReplacementToks - 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.
198  ///
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);
205 
206  /// Expand the arguments of a function-like macro so that we can quickly
207  /// return preexpanded tokens from Tokens.
208  void ExpandFunctionArguments();
209 
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);
216 
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;
221 
222  /// Creates SLocEntries and updates the locations of macro argument
223  /// tokens to their new expanded locations.
224  ///
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);
229 
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,
235  Preprocessor &PP);
236 
237  void PropagateLineStartLeadingSpaceInfo(Token &Result);
238 };
239 
240 } // namespace clang
241 
242 #endif // LLVM_CLANG_LEX_TOKENLEXER_H
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 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
void Init(Token &Tok, SourceLocation ELEnd, MacroInfo *MI, MacroArgs *Actuals)
Initialize this TokenLexer to expand from the specified macro with the specified argument information...
Definition: TokenLexer.cpp:39
TokenLexer(const Token *TokArray, unsigned NumToks, bool DisableExpansion, bool ownsTokens, Preprocessor &pp)
Create a TokenLexer for the specified token stream.
Definition: TokenLexer.h:114
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:105
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
If the next token lexed will pop this macro off the expansion stack, return 2.
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