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