1 //===--- Token.h - Token interface ------------------------------*- 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 //
9 //  This file defines the Token interface.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_LEX_TOKEN_H
14 #define LLVM_CLANG_LEX_TOKEN_H
15 
16 #include "clang/Basic/SourceLocation.h"
17 #include "clang/Basic/TokenKinds.h"
18 #include "llvm/ADT/StringRef.h"
19 #include <cassert>
20 
21 namespace clang {
22 
23 class IdentifierInfo;
24 
25 /// Token - This structure provides full information about a lexed token.
26 /// It is not intended to be space efficient, it is intended to return as much
27 /// information as possible about each returned token.  This is expected to be
28 /// compressed into a smaller form if memory footprint is important.
29 ///
30 /// The parser can create a special "annotation token" representing a stream of
31 /// tokens that were parsed and semantically resolved, e.g.: "foo::MyClass<int>"
32 /// can be represented by a single typename annotation token that carries
33 /// information about the SourceRange of the tokens and the type object.
34 class Token {
35   /// The location of the token. This is actually a SourceLocation.
36   SourceLocation::UIntTy Loc;
37 
38   // Conceptually these next two fields could be in a union.  However, this
39   // causes gcc 4.2 to pessimize LexTokenInternal, a very performance critical
40   // routine. Keeping as separate members with casts until a more beautiful fix
41   // presents itself.
42 
43   /// UintData - This holds either the length of the token text, when
44   /// a normal token, or the end of the SourceRange when an annotation
45   /// token.
46   SourceLocation::UIntTy UintData;
47 
48   /// PtrData - This is a union of four different pointer types, which depends
49   /// on what type of token this is:
50   ///  Identifiers, keywords, etc:
51   ///    This is an IdentifierInfo*, which contains the uniqued identifier
52   ///    spelling.
53   ///  Literals:  isLiteral() returns true.
54   ///    This is a pointer to the start of the token in a text buffer, which
55   ///    may be dirty (have trigraphs / escaped newlines).
56   ///  Annotations (resolved type names, C++ scopes, etc): isAnnotation().
57   ///    This is a pointer to sema-specific data for the annotation token.
58   ///  Eof:
59   //     This is a pointer to a Decl.
60   ///  Other:
61   ///    This is null.
62   void *PtrData;
63 
64   /// Kind - The actual flavor of token this is.
65   tok::TokenKind Kind;
66 
67   /// Flags - Bits we track about this token, members of the TokenFlags enum.
68   unsigned short Flags;
69 
70 public:
71   // Various flags set per token:
72   enum TokenFlags {
73     StartOfLine = 0x01,   // At start of line or only after whitespace
74                           // (considering the line after macro expansion).
75     LeadingSpace = 0x02,  // Whitespace exists before this token (considering
76                           // whitespace after macro expansion).
77     DisableExpand = 0x04, // This identifier may never be macro expanded.
78     NeedsCleaning = 0x08, // Contained an escaped newline or trigraph.
79     LeadingEmptyMacro = 0x10, // Empty macro exists before this token.
80     HasUDSuffix = 0x20,  // This string or character literal has a ud-suffix.
81     HasUCN = 0x40,       // This identifier contains a UCN.
82     IgnoredComma = 0x80, // This comma is not a macro argument separator (MS).
83     StringifiedInMacro = 0x100, // This string or character literal is formed by
84                                 // macro stringizing or charizing operator.
85     CommaAfterElided = 0x200, // The comma following this token was elided (MS).
86     IsEditorPlaceholder = 0x400, // This identifier is a placeholder.
87     IsReinjected = 0x800, // A phase 4 token that was produced before and
88                           // re-added, e.g. via EnterTokenStream. Annotation
89                           // tokens are *not* reinjected.
90   };
91 
92   tok::TokenKind getKind() const { return Kind; }
93   void setKind(tok::TokenKind K) { Kind = K; }
94 
95   /// is/isNot - Predicates to check if this token is a specific kind, as in
96   /// "if (Tok.is(tok::l_brace)) {...}".
97   bool is(tok::TokenKind K) const { return Kind == K; }
98   bool isNot(tok::TokenKind K) const { return Kind != K; }
99   bool isOneOf(tok::TokenKind K1, tok::TokenKind K2) const {
100     return is(K1) || is(K2);
101   }
102   template <typename... Ts> bool isOneOf(tok::TokenKind K1, Ts... Ks) const {
103     return is(K1) || isOneOf(Ks...);
104   }
105 
106   /// Return true if this is a raw identifier (when lexing
107   /// in raw mode) or a non-keyword identifier (when lexing in non-raw mode).
108   bool isAnyIdentifier() const {
109     return tok::isAnyIdentifier(getKind());
110   }
111 
112   /// Return true if this is a "literal", like a numeric
113   /// constant, string, etc.
114   bool isLiteral() const {
115     return tok::isLiteral(getKind());
116   }
117 
118   /// Return true if this is any of tok::annot_* kind tokens.
119   bool isAnnotation() const {
120     return tok::isAnnotation(getKind());
121   }
122 
123   /// Return a source location identifier for the specified
124   /// offset in the current file.
125   SourceLocation getLocation() const {
126     return SourceLocation::getFromRawEncoding(Loc);
127   }
128   unsigned getLength() const {
129     assert(!isAnnotation() && "Annotation tokens have no length field");
130     return UintData;
131   }
132 
133   void setLocation(SourceLocation L) { Loc = L.getRawEncoding(); }
134   void setLength(unsigned Len) {
135     assert(!isAnnotation() && "Annotation tokens have no length field");
136     UintData = Len;
137   }
138 
139   SourceLocation getAnnotationEndLoc() const {
140     assert(isAnnotation() && "Used AnnotEndLocID on non-annotation token");
141     return SourceLocation::getFromRawEncoding(UintData ? UintData : Loc);
142   }
143   void setAnnotationEndLoc(SourceLocation L) {
144     assert(isAnnotation() && "Used AnnotEndLocID on non-annotation token");
145     UintData = L.getRawEncoding();
146   }
147 
148   SourceLocation getLastLoc() const {
149     return isAnnotation() ? getAnnotationEndLoc() : getLocation();
150   }
151 
152   SourceLocation getEndLoc() const {
153     return isAnnotation() ? getAnnotationEndLoc()
154                           : getLocation().getLocWithOffset(getLength());
155   }
156 
157   /// SourceRange of the group of tokens that this annotation token
158   /// represents.
159   SourceRange getAnnotationRange() const {
160     return SourceRange(getLocation(), getAnnotationEndLoc());
161   }
162   void setAnnotationRange(SourceRange R) {
163     setLocation(R.getBegin());
164     setAnnotationEndLoc(R.getEnd());
165   }
166 
167   const char *getName() const { return tok::getTokenName(Kind); }
168 
169   /// Reset all flags to cleared.
170   void startToken() {
171     Kind = tok::unknown;
172     Flags = 0;
173     PtrData = nullptr;
174     UintData = 0;
175     Loc = SourceLocation().getRawEncoding();
176   }
177 
178   IdentifierInfo *getIdentifierInfo() const {
179     assert(isNot(tok::raw_identifier) &&
180            "getIdentifierInfo() on a tok::raw_identifier token!");
181     assert(!isAnnotation() &&
182            "getIdentifierInfo() on an annotation token!");
183     if (isLiteral()) return nullptr;
184     if (is(tok::eof)) return nullptr;
185     return (IdentifierInfo*) PtrData;
186   }
187   void setIdentifierInfo(IdentifierInfo *II) {
188     PtrData = (void*) II;
189   }
190 
191   const void *getEofData() const {
192     assert(is(tok::eof));
193     return reinterpret_cast<const void *>(PtrData);
194   }
195   void setEofData(const void *D) {
196     assert(is(tok::eof));
197     assert(!PtrData);
198     PtrData = const_cast<void *>(D);
199   }
200 
201   /// getRawIdentifier - For a raw identifier token (i.e., an identifier
202   /// lexed in raw mode), returns a reference to the text substring in the
203   /// buffer if known.
204   StringRef getRawIdentifier() const {
205     assert(is(tok::raw_identifier));
206     return StringRef(reinterpret_cast<const char *>(PtrData), getLength());
207   }
208   void setRawIdentifierData(const char *Ptr) {
209     assert(is(tok::raw_identifier));
210     PtrData = const_cast<char*>(Ptr);
211   }
212 
213   /// getLiteralData - For a literal token (numeric constant, string, etc), this
214   /// returns a pointer to the start of it in the text buffer if known, null
215   /// otherwise.
216   const char *getLiteralData() const {
217     assert(isLiteral() && "Cannot get literal data of non-literal");
218     return reinterpret_cast<const char*>(PtrData);
219   }
220   void setLiteralData(const char *Ptr) {
221     assert(isLiteral() && "Cannot set literal data of non-literal");
222     PtrData = const_cast<char*>(Ptr);
223   }
224 
225   void *getAnnotationValue() const {
226     assert(isAnnotation() && "Used AnnotVal on non-annotation token");
227     return PtrData;
228   }
229   void setAnnotationValue(void *val) {
230     assert(isAnnotation() && "Used AnnotVal on non-annotation token");
231     PtrData = val;
232   }
233 
234   /// Set the specified flag.
235   void setFlag(TokenFlags Flag) {
236     Flags |= Flag;
237   }
238 
239   /// Get the specified flag.
240   bool getFlag(TokenFlags Flag) const {
241     return (Flags & Flag) != 0;
242   }
243 
244   /// Unset the specified flag.
245   void clearFlag(TokenFlags Flag) {
246     Flags &= ~Flag;
247   }
248 
249   /// Return the internal represtation of the flags.
250   ///
251   /// This is only intended for low-level operations such as writing tokens to
252   /// disk.
253   unsigned getFlags() const {
254     return Flags;
255   }
256 
257   /// Set a flag to either true or false.
258   void setFlagValue(TokenFlags Flag, bool Val) {
259     if (Val)
260       setFlag(Flag);
261     else
262       clearFlag(Flag);
263   }
264 
265   /// isAtStartOfLine - Return true if this token is at the start of a line.
266   ///
267   bool isAtStartOfLine() const { return getFlag(StartOfLine); }
268 
269   /// Return true if this token has whitespace before it.
270   ///
271   bool hasLeadingSpace() const { return getFlag(LeadingSpace); }
272 
273   /// Return true if this identifier token should never
274   /// be expanded in the future, due to C99 6.10.3.4p2.
275   bool isExpandDisabled() const { return getFlag(DisableExpand); }
276 
277   /// Return true if we have an ObjC keyword identifier.
278   bool isObjCAtKeyword(tok::ObjCKeywordKind objcKey) const;
279 
280   /// Return the ObjC keyword kind.
281   tok::ObjCKeywordKind getObjCKeywordID() const;
282 
283   /// Return true if this token has trigraphs or escaped newlines in it.
284   bool needsCleaning() const { return getFlag(NeedsCleaning); }
285 
286   /// Return true if this token has an empty macro before it.
287   ///
288   bool hasLeadingEmptyMacro() const { return getFlag(LeadingEmptyMacro); }
289 
290   /// Return true if this token is a string or character literal which
291   /// has a ud-suffix.
292   bool hasUDSuffix() const { return getFlag(HasUDSuffix); }
293 
294   /// Returns true if this token contains a universal character name.
295   bool hasUCN() const { return getFlag(HasUCN); }
296 
297   /// Returns true if this token is formed by macro by stringizing or charizing
298   /// operator.
299   bool stringifiedInMacro() const { return getFlag(StringifiedInMacro); }
300 
301   /// Returns true if the comma after this token was elided.
302   bool commaAfterElided() const { return getFlag(CommaAfterElided); }
303 
304   /// Returns true if this token is an editor placeholder.
305   ///
306   /// Editor placeholders are produced by the code-completion engine and are
307   /// represented as characters between '<#' and '#>' in the source code. The
308   /// lexer uses identifier tokens to represent placeholders.
309   bool isEditorPlaceholder() const { return getFlag(IsEditorPlaceholder); }
310 };
311 
312 /// Information about the conditional stack (\#if directives)
313 /// currently active.
314 struct PPConditionalInfo {
315   /// Location where the conditional started.
316   SourceLocation IfLoc;
317 
318   /// True if this was contained in a skipping directive, e.g.,
319   /// in a "\#if 0" block.
320   bool WasSkipping;
321 
322   /// True if we have emitted tokens already, and now we're in
323   /// an \#else block or something.  Only useful in Skipping blocks.
324   bool FoundNonSkip;
325 
326   /// True if we've seen a \#else in this block.  If so,
327   /// \#elif/\#else directives are not allowed.
328   bool FoundElse;
329 };
330 
331 } // end namespace clang
332 
333 #endif // LLVM_CLANG_LEX_TOKEN_H
334