clang  10.0.0git
Tokens.h
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1 //===- Tokens.h - collect tokens from preprocessing --------------*- C++-*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 // Record tokens that a preprocessor emits and define operations to map between
9 // the tokens written in a file and tokens produced by the preprocessor.
10 //
11 // When running the compiler, there are two token streams we are interested in:
12 // - "spelled" tokens directly correspond to a substring written in some
13 // source file.
14 // - "expanded" tokens represent the result of preprocessing, parses consumes
15 // this token stream to produce the AST.
16 //
17 // Expanded tokens correspond directly to locations found in the AST, allowing
18 // to find subranges of the token stream covered by various AST nodes. Spelled
19 // tokens correspond directly to the source code written by the user.
20 //
21 // To allow composing these two use-cases, we also define operations that map
22 // between expanded and spelled tokens that produced them (macro calls,
23 // directives, etc).
24 //
25 //===----------------------------------------------------------------------===//
26 
27 #ifndef LLVM_CLANG_TOOLING_SYNTAX_TOKENS_H
28 #define LLVM_CLANG_TOOLING_SYNTAX_TOKENS_H
29 
34 #include "clang/Basic/TokenKinds.h"
35 #include "clang/Lex/Token.h"
36 #include "llvm/ADT/ArrayRef.h"
37 #include "llvm/ADT/Optional.h"
38 #include "llvm/ADT/StringRef.h"
39 #include "llvm/Support/Compiler.h"
40 #include "llvm/Support/raw_ostream.h"
41 #include <cstdint>
42 #include <tuple>
43 
44 namespace clang {
45 class Preprocessor;
46 
47 namespace syntax {
48 
49 /// A half-open character range inside a particular file, the start offset is
50 /// included and the end offset is excluded from the range.
51 struct FileRange {
52  /// EXPECTS: File.isValid() && Begin <= End.
53  FileRange(FileID File, unsigned BeginOffset, unsigned EndOffset);
54  /// EXPECTS: BeginLoc.isValid() && BeginLoc.isFileID().
55  FileRange(const SourceManager &SM, SourceLocation BeginLoc, unsigned Length);
56  /// EXPECTS: BeginLoc.isValid() && BeginLoc.isFileID(), Begin <= End and files
57  /// are the same.
58  FileRange(const SourceManager &SM, SourceLocation BeginLoc,
59  SourceLocation EndLoc);
60 
61  FileID file() const { return File; }
62  /// Start is a start offset (inclusive) in the corresponding file.
63  unsigned beginOffset() const { return Begin; }
64  /// End offset (exclusive) in the corresponding file.
65  unsigned endOffset() const { return End; }
66 
67  unsigned length() const { return End - Begin; }
68 
69  /// Check if \p Offset is inside the range.
70  bool contains(unsigned Offset) const {
71  return Begin <= Offset && Offset < End;
72  }
73  /// Check \p Offset is inside the range or equal to its endpoint.
74  bool touches(unsigned Offset) const {
75  return Begin <= Offset && Offset <= End;
76  }
77 
78  /// Gets the substring that this FileRange refers to.
79  llvm::StringRef text(const SourceManager &SM) const;
80 
81  /// Convert to the clang range. The returned range is always a char range,
82  /// never a token range.
83  CharSourceRange toCharRange(const SourceManager &SM) const;
84 
85  friend bool operator==(const FileRange &L, const FileRange &R) {
86  return std::tie(L.File, L.Begin, L.End) == std::tie(R.File, R.Begin, R.End);
87  }
88  friend bool operator!=(const FileRange &L, const FileRange &R) {
89  return !(L == R);
90  }
91 
92 private:
93  FileID File;
94  unsigned Begin;
95  unsigned End;
96 };
97 
98 /// For debugging purposes.
99 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const FileRange &R);
100 
101 /// A token coming directly from a file or from a macro invocation. Has just
102 /// enough information to locate the token in the source code.
103 /// Can represent both expanded and spelled tokens.
104 class Token {
105 public:
106  Token(SourceLocation Location, unsigned Length, tok::TokenKind Kind);
107  /// EXPECTS: clang::Token is not an annotation token.
108  explicit Token(const clang::Token &T);
109 
110  tok::TokenKind kind() const { return Kind; }
111  /// Location of the first character of a token.
112  SourceLocation location() const { return Location; }
113  /// Location right after the last character of a token.
115  return Location.getLocWithOffset(Length);
116  }
117  unsigned length() const { return Length; }
118 
119  /// Get the substring covered by the token. Note that will include all
120  /// digraphs, newline continuations, etc. E.g. tokens for 'int' and
121  /// in\
122  /// t
123  /// both have the same kind tok::kw_int, but results of text() are different.
124  llvm::StringRef text(const SourceManager &SM) const;
125 
126  /// Gets a range of this token.
127  /// EXPECTS: token comes from a file, not from a macro expansion.
128  FileRange range(const SourceManager &SM) const;
129 
130  /// Given two tokens inside the same file, returns a file range that starts at
131  /// \p First and ends at \p Last.
132  /// EXPECTS: First and Last are file tokens from the same file, Last starts
133  /// after First.
134  static FileRange range(const SourceManager &SM, const syntax::Token &First,
135  const syntax::Token &Last);
136 
137  std::string dumpForTests(const SourceManager &SM) const;
138  /// For debugging purposes.
139  std::string str() const;
140 
141 private:
142  SourceLocation Location;
143  unsigned Length;
145 };
146 /// For debugging purposes. Equivalent to a call to Token::str().
147 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Token &T);
148 
149 /// A list of tokens obtained by preprocessing a text buffer and operations to
150 /// map between the expanded and spelled tokens, i.e. TokenBuffer has
151 /// information about two token streams:
152 /// 1. Expanded tokens: tokens produced by the preprocessor after all macro
153 /// replacements,
154 /// 2. Spelled tokens: corresponding directly to the source code of a file
155 /// before any macro replacements occurred.
156 /// Here's an example to illustrate a difference between those two:
157 /// #define FOO 10
158 /// int a = FOO;
159 ///
160 /// Spelled tokens are {'#','define','FOO','10','int','a','=','FOO',';'}.
161 /// Expanded tokens are {'int','a','=','10',';','eof'}.
162 ///
163 /// Note that the expanded token stream has a tok::eof token at the end, the
164 /// spelled tokens never store a 'eof' token.
165 ///
166 /// The full list expanded tokens can be obtained with expandedTokens(). Spelled
167 /// tokens for each of the files can be obtained via spelledTokens(FileID).
168 ///
169 /// To map between the expanded and spelled tokens use findSpelledByExpanded().
170 ///
171 /// To build a token buffer use the TokenCollector class. You can also compute
172 /// the spelled tokens of a file using the tokenize() helper.
173 ///
174 /// FIXME: allow to map from spelled to expanded tokens when use-case shows up.
175 /// FIXME: allow mappings into macro arguments.
176 class TokenBuffer {
177 public:
178  TokenBuffer(const SourceManager &SourceMgr) : SourceMgr(&SourceMgr) {}
179  /// All tokens produced by the preprocessor after all macro replacements,
180  /// directives, etc. Source locations found in the clang AST will always
181  /// point to one of these tokens.
182  /// Tokens are in TU order (per SourceManager::isBeforeInTranslationUnit()).
183  /// FIXME: figure out how to handle token splitting, e.g. '>>' can be split
184  /// into two '>' tokens by the parser. However, TokenBuffer currently
185  /// keeps it as a single '>>' token.
187  return ExpandedTokens;
188  }
189 
190  /// Returns the subrange of expandedTokens() corresponding to the closed
191  /// token range R.
192  llvm::ArrayRef<syntax::Token> expandedTokens(SourceRange R) const;
193 
194  /// Find the subrange of spelled tokens that produced the corresponding \p
195  /// Expanded tokens.
196  ///
197  /// EXPECTS: \p Expanded is a subrange of expandedTokens().
198  ///
199  /// Will fail if the expanded tokens do not correspond to a
200  /// sequence of spelled tokens. E.g. for the following example:
201  ///
202  /// #define FIRST f1 f2 f3
203  /// #define SECOND s1 s2 s3
204  ///
205  /// a FIRST b SECOND c // expanded tokens are: a f1 f2 f3 b s1 s2 s3 c
206  ///
207  /// the results would be:
208  /// expanded => spelled
209  /// ------------------------
210  /// a => a
211  /// s1 s2 s3 => SECOND
212  /// a f1 f2 f3 => a FIRST
213  /// a f1 => can't map
214  /// s1 s2 => can't map
215  ///
216  /// If \p Expanded is empty, the returned value is llvm::None.
217  /// Complexity is logarithmic.
219  spelledForExpanded(llvm::ArrayRef<syntax::Token> Expanded) const;
220 
221  /// An expansion produced by the preprocessor, includes macro expansions and
222  /// preprocessor directives. Preprocessor always maps a non-empty range of
223  /// spelled tokens to a (possibly empty) range of expanded tokens. Here is a
224  /// few examples of expansions:
225  /// #pragma once // Expands to an empty range.
226  /// #define FOO 1 2 3 // Expands an empty range.
227  /// FOO // Expands to "1 2 3".
228  /// FIXME(ibiryukov): implement this, currently #include expansions are empty.
229  /// #include <vector> // Expands to tokens produced by the include.
230  struct Expansion {
233  };
234  /// If \p Spelled starts a mapping (e.g. if it's a macro name or '#' starting
235  /// a preprocessor directive) return the subrange of expanded tokens that the
236  /// macro expands to.
238  expansionStartingAt(const syntax::Token *Spelled) const;
239 
240  /// Lexed tokens of a file before preprocessing. E.g. for the following input
241  /// #define DECL(name) int name = 10
242  /// DECL(a);
243  /// spelledTokens() returns
244  /// {"#", "define", "DECL", "(", "name", ")", "int", "name", "=", "10",
245  /// "DECL", "(", "a", ")", ";"}
246  llvm::ArrayRef<syntax::Token> spelledTokens(FileID FID) const;
247 
248  /// Get all tokens that expand a macro in \p FID. For the following input
249  /// #define FOO B
250  /// #define FOO2(X) int X
251  /// FOO2(XY)
252  /// int B;
253  /// FOO;
254  /// macroExpansions() returns {"FOO2", "FOO"} (from line 3 and 5
255  /// respecitvely).
256  std::vector<const syntax::Token *> macroExpansions(FileID FID) const;
257 
258  const SourceManager &sourceManager() const { return *SourceMgr; }
259 
260  std::string dumpForTests() const;
261 
262 private:
263  /// Describes a mapping between a continuous subrange of spelled tokens and
264  /// expanded tokens. Represents macro expansions, preprocessor directives,
265  /// conditionally disabled pp regions, etc.
266  /// #define FOO 1+2
267  /// #define BAR(a) a + 1
268  /// FOO // invocation #1, tokens = {'1','+','2'}, macroTokens = {'FOO'}.
269  /// BAR(1) // invocation #2, tokens = {'a', '+', '1'},
270  /// macroTokens = {'BAR', '(', '1', ')'}.
271  struct Mapping {
272  // Positions in the corresponding spelled token stream. The corresponding
273  // range is never empty.
274  unsigned BeginSpelled = 0;
275  unsigned EndSpelled = 0;
276  // Positions in the expanded token stream. The corresponding range can be
277  // empty.
278  unsigned BeginExpanded = 0;
279  unsigned EndExpanded = 0;
280 
281  /// For debugging purposes.
282  std::string str() const;
283  };
284  /// Spelled tokens of the file with information about the subranges.
285  struct MarkedFile {
286  /// Lexed, but not preprocessed, tokens of the file. These map directly to
287  /// text in the corresponding files and include tokens of all preprocessor
288  /// directives.
289  /// FIXME: spelled tokens don't change across FileID that map to the same
290  /// FileEntry. We could consider deduplicating them to save memory.
291  std::vector<syntax::Token> SpelledTokens;
292  /// A sorted list to convert between the spelled and expanded token streams.
293  std::vector<Mapping> Mappings;
294  /// The first expanded token produced for this FileID.
295  unsigned BeginExpanded = 0;
296  unsigned EndExpanded = 0;
297  };
298 
299  friend class TokenCollector;
300 
301  /// Maps a single expanded token to its spelled counterpart or a mapping that
302  /// produced it.
303  std::pair<const syntax::Token *, const Mapping *>
304  spelledForExpandedToken(const syntax::Token *Expanded) const;
305 
306  /// Token stream produced after preprocessing, conceputally this captures the
307  /// same stream as 'clang -E' (excluding the preprocessor directives like
308  /// #file, etc.).
309  std::vector<syntax::Token> ExpandedTokens;
310  llvm::DenseMap<FileID, MarkedFile> Files;
311  // The value is never null, pointer instead of reference to avoid disabling
312  // implicit assignment operator.
313  const SourceManager *SourceMgr;
314 };
315 
316 /// The spelled tokens that overlap or touch a spelling location Loc.
317 /// This always returns 0-2 tokens.
320 
321 /// The identifier token that overlaps or touches a spelling location Loc.
322 /// If there is none, returns nullptr.
323 const syntax::Token *
325  const syntax::TokenBuffer &Tokens);
326 
327 /// Lex the text buffer, corresponding to \p FID, in raw mode and record the
328 /// resulting spelled tokens. Does minimal post-processing on raw identifiers,
329 /// setting the appropriate token kind (instead of the raw_identifier reported
330 /// by lexer in raw mode). This is a very low-level function, most users should
331 /// prefer to use TokenCollector. Lexing in raw mode produces wildly different
332 /// results from what one might expect when running a C++ frontend, e.g.
333 /// preprocessor does not run at all.
334 /// The result will *not* have a 'eof' token at the end.
335 std::vector<syntax::Token> tokenize(FileID FID, const SourceManager &SM,
336  const LangOptions &LO);
337 
338 /// Collects tokens for the main file while running the frontend action. An
339 /// instance of this object should be created on
340 /// FrontendAction::BeginSourceFile() and the results should be consumed after
341 /// FrontendAction::Execute() finishes.
343 public:
344  /// Adds the hooks to collect the tokens. Should be called before the
345  /// preprocessing starts, i.e. as a part of BeginSourceFile() or
346  /// CreateASTConsumer().
348 
349  /// Finalizes token collection. Should be called after preprocessing is
350  /// finished, i.e. after running Execute().
351  LLVM_NODISCARD TokenBuffer consume() &&;
352 
353 private:
354  /// Maps from a start to an end spelling location of transformations
355  /// performed by the preprocessor. These include:
356  /// 1. range from '#' to the last token in the line for PP directives,
357  /// 2. macro name and arguments for macro expansions.
358  /// Note that we record only top-level macro expansions, intermediate
359  /// expansions (e.g. inside macro arguments) are ignored.
360  ///
361  /// Used to find correct boundaries of macro calls and directives when
362  /// building mappings from spelled to expanded tokens.
363  ///
364  /// Logically, at each point of the preprocessor execution there is a stack of
365  /// macro expansions being processed and we could use it to recover the
366  /// location information we need. However, the public preprocessor API only
367  /// exposes the points when macro expansions start (when we push a macro onto
368  /// the stack) and not when they end (when we pop a macro from the stack).
369  /// To workaround this limitation, we rely on source location information
370  /// stored in this map.
371  using PPExpansions = llvm::DenseMap</*SourceLocation*/ int, SourceLocation>;
372  class Builder;
373  class CollectPPExpansions;
374 
375  std::vector<syntax::Token> Expanded;
376  // FIXME: we only store macro expansions, also add directives(#pragma, etc.)
377  PPExpansions Expansions;
378  Preprocessor &PP;
379  CollectPPExpansions *Collector;
380 };
381 
382 } // namespace syntax
383 } // namespace clang
384 
385 #endif
llvm::StringRef text(const SourceManager &SM) const
Gets the substring that this FileRange refers to.
Definition: Tokens.cpp:112
const SourceManager & sourceManager() const
Definition: Tokens.h:258
SourceLocation getLocWithOffset(int Offset) const
Return a source location with the specified offset from this SourceLocation.
friend bool operator==(const FileRange &L, const FileRange &R)
Definition: Tokens.h:85
Defines the clang::FileManager interface and associated types.
llvm::ArrayRef< syntax::Token > spelledTokensTouching(SourceLocation Loc, const syntax::TokenBuffer &Tokens)
The spelled tokens that overlap or touch a spelling location Loc.
Definition: Tokens.cpp:258
Defines the SourceManager interface.
llvm::raw_ostream & operator<<(llvm::raw_ostream &OS, NodeKind K)
For debugging purposes.
Definition: Nodes.cpp:13
StringRef P
A token coming directly from a file or from a macro invocation.
Definition: Tokens.h:104
RangeSelector range(RangeSelector Begin, RangeSelector End)
Selects from the start of Begin and to the end of End.
FileRange(FileID File, unsigned BeginOffset, unsigned EndOffset)
EXPECTS: File.isValid() && Begin <= End.
Definition: Tokens.cpp:78
llvm::ArrayRef< syntax::Token > expandedTokens() const
All tokens produced by the preprocessor after all macro replacements, directives, etc...
Definition: Tokens.h:186
Token - This structure provides full information about a lexed token.
Definition: Token.h:34
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:53
llvm::ArrayRef< syntax::Token > Spelled
Definition: Tokens.h:231
SourceLocation location() const
Location of the first character of a token.
Definition: Tokens.h:112
CharSourceRange toCharRange(const SourceManager &SM) const
Convert to the clang range.
Definition: Tokens.cpp:138
bool touches(unsigned Offset) const
Check Offset is inside the range or equal to its endpoint.
Definition: Tokens.h:74
SourceLocation endLocation() const
Location right after the last character of a token.
Definition: Tokens.h:114
unsigned length() const
Definition: Tokens.h:117
TokenBuffer(const SourceManager &SourceMgr)
Definition: Tokens.h:178
bool contains(unsigned Offset) const
Check if Offset is inside the range.
Definition: Tokens.h:70
unsigned Offset
Definition: Format.cpp:1827
Defines the clang::LangOptions interface.
Represents a character-granular source range.
const syntax::Token * spelledIdentifierTouching(SourceLocation Loc, const syntax::TokenBuffer &Tokens)
The identifier token that overlaps or touches a spelling location Loc.
Definition: Tokens.cpp:272
unsigned length() const
Definition: Tokens.h:67
const SourceManager & SM
Definition: Format.cpp:1685
Kind
Encodes a location in the source.
tok::TokenKind kind() const
Definition: Tokens.h:110
TokenKind
Provides a simple uniform namespace for tokens from all C languages.
Definition: TokenKinds.h:24
FileID file() const
Definition: Tokens.h:61
An opaque identifier used by SourceManager which refers to a source file (MemoryBuffer) along with it...
unsigned beginOffset() const
Start is a start offset (inclusive) in the corresponding file.
Definition: Tokens.h:63
Dataflow Directional Tag Classes.
A half-open character range inside a particular file, the start offset is included and the end offset...
Definition: Tokens.h:51
Collects tokens for the main file while running the frontend action.
Definition: Tokens.h:342
std::vector< syntax::Token > tokenize(FileID FID, const SourceManager &SM, const LangOptions &LO)
Lex the text buffer, corresponding to FID, in raw mode and record the resulting spelled tokens...
Definition: Tokens.cpp:296
Defines the clang::TokenKind enum and support functions.
Defines the clang::SourceLocation class and associated facilities.
An expansion produced by the preprocessor, includes macro expansions and preprocessor directives...
Definition: Tokens.h:230
friend bool operator!=(const FileRange &L, const FileRange &R)
Definition: Tokens.h:88
A list of tokens obtained by preprocessing a text buffer and operations to map between the expanded a...
Definition: Tokens.h:176
A trivial tuple used to represent a source range.
llvm::ArrayRef< syntax::Token > Expanded
Definition: Tokens.h:232
unsigned endOffset() const
End offset (exclusive) in the corresponding file.
Definition: Tokens.h:65
This class handles loading and caching of source files into memory.
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:128