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      1 //===--- MacroInfo.h - Information about #defined identifiers ---*- 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 MacroInfo interface.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_CLANG_MACROINFO_H
     15 #define LLVM_CLANG_MACROINFO_H
     16 
     17 #include "clang/Lex/Token.h"
     18 #include "llvm/ADT/SmallVector.h"
     19 #include "llvm/Support/Allocator.h"
     20 #include <cassert>
     21 
     22 namespace clang {
     23   class Preprocessor;
     24 
     25 /// MacroInfo - Each identifier that is #define'd has an instance of this class
     26 /// associated with it, used to implement macro expansion.
     27 class MacroInfo {
     28   //===--------------------------------------------------------------------===//
     29   // State set when the macro is defined.
     30 
     31   /// Location - This is the place the macro is defined.
     32   SourceLocation Location;
     33   /// EndLocation - The location of the last token in the macro.
     34   SourceLocation EndLocation;
     35 
     36   /// Arguments - The list of arguments for a function-like macro.  This can be
     37   /// empty, for, e.g. "#define X()".  In a C99-style variadic macro, this
     38   /// includes the __VA_ARGS__ identifier on the list.
     39   IdentifierInfo **ArgumentList;
     40   unsigned NumArguments;
     41 
     42   /// ReplacementTokens - This is the list of tokens that the macro is defined
     43   /// to.
     44   llvm::SmallVector<Token, 8> ReplacementTokens;
     45 
     46   /// \brief Length in characters of the macro definition.
     47   mutable unsigned DefinitionLength;
     48   mutable bool IsDefinitionLengthCached : 1;
     49 
     50   /// IsFunctionLike - True if this macro is a function-like macro, false if it
     51   /// is an object-like macro.
     52   bool IsFunctionLike : 1;
     53 
     54   /// IsC99Varargs - True if this macro is of the form "#define X(...)" or
     55   /// "#define X(Y,Z,...)".  The __VA_ARGS__ token should be replaced with the
     56   /// contents of "..." in an invocation.
     57   bool IsC99Varargs : 1;
     58 
     59   /// IsGNUVarargs -  True if this macro is of the form "#define X(a...)".  The
     60   /// "a" identifier in the replacement list will be replaced with all arguments
     61   /// of the macro starting with the specified one.
     62   bool IsGNUVarargs : 1;
     63 
     64   /// IsBuiltinMacro - True if this is a builtin macro, such as __LINE__, and if
     65   /// it has not yet been redefined or undefined.
     66   bool IsBuiltinMacro : 1;
     67 
     68   /// IsFromAST - True if this macro was loaded from an AST file.
     69   bool IsFromAST : 1;
     70 
     71 private:
     72   //===--------------------------------------------------------------------===//
     73   // State that changes as the macro is used.
     74 
     75   /// IsDisabled - True if we have started an expansion of this macro already.
     76   /// This disbles recursive expansion, which would be quite bad for things like
     77   /// #define A A.
     78   bool IsDisabled : 1;
     79 
     80   /// IsUsed - True if this macro is either defined in the main file and has
     81   /// been used, or if it is not defined in the main file.  This is used to
     82   /// emit -Wunused-macros diagnostics.
     83   bool IsUsed : 1;
     84 
     85   /// AllowRedefinitionsWithoutWarning - True if this macro can be redefined
     86   /// without emitting a warning.
     87   bool IsAllowRedefinitionsWithoutWarning : 1;
     88 
     89   /// \brief Must warn if the macro is unused at the end of translation unit.
     90   bool IsWarnIfUnused : 1;
     91 
     92    ~MacroInfo() {
     93     assert(ArgumentList == 0 && "Didn't call destroy before dtor!");
     94   }
     95 
     96 public:
     97   MacroInfo(SourceLocation DefLoc);
     98   MacroInfo(const MacroInfo &MI, llvm::BumpPtrAllocator &PPAllocator);
     99 
    100   /// FreeArgumentList - Free the argument list of the macro, restoring it to a
    101   /// state where it can be reused for other devious purposes.
    102   void FreeArgumentList() {
    103     ArgumentList = 0;
    104     NumArguments = 0;
    105   }
    106 
    107   /// Destroy - destroy this MacroInfo object.
    108   void Destroy() {
    109     FreeArgumentList();
    110     this->~MacroInfo();
    111   }
    112 
    113   /// getDefinitionLoc - Return the location that the macro was defined at.
    114   ///
    115   SourceLocation getDefinitionLoc() const { return Location; }
    116 
    117   /// setDefinitionEndLoc - Set the location of the last token in the macro.
    118   ///
    119   void setDefinitionEndLoc(SourceLocation EndLoc) { EndLocation = EndLoc; }
    120   /// getDefinitionEndLoc - Return the location of the last token in the macro.
    121   ///
    122   SourceLocation getDefinitionEndLoc() const { return EndLocation; }
    123 
    124   /// \brief Get length in characters of the macro definition.
    125   unsigned getDefinitionLength(SourceManager &SM) const {
    126     if (IsDefinitionLengthCached)
    127       return DefinitionLength;
    128     return getDefinitionLengthSlow(SM);
    129   }
    130 
    131   /// isIdenticalTo - Return true if the specified macro definition is equal to
    132   /// this macro in spelling, arguments, and whitespace.  This is used to emit
    133   /// duplicate definition warnings.  This implements the rules in C99 6.10.3.
    134   bool isIdenticalTo(const MacroInfo &Other, Preprocessor &PP) const;
    135 
    136   /// setIsBuiltinMacro - Set or clear the isBuiltinMacro flag.
    137   ///
    138   void setIsBuiltinMacro(bool Val = true) {
    139     IsBuiltinMacro = Val;
    140   }
    141 
    142   /// setIsUsed - Set the value of the IsUsed flag.
    143   ///
    144   void setIsUsed(bool Val) {
    145     IsUsed = Val;
    146   }
    147 
    148   /// setIsAllowRedefinitionsWithoutWarning - Set the value of the
    149   /// IsAllowRedefinitionsWithoutWarning flag.
    150   void setIsAllowRedefinitionsWithoutWarning(bool Val) {
    151     IsAllowRedefinitionsWithoutWarning = Val;
    152   }
    153 
    154   /// \brief Set the value of the IsWarnIfUnused flag.
    155   void setIsWarnIfUnused(bool val) {
    156     IsWarnIfUnused = val;
    157   }
    158 
    159   /// setArgumentList - Set the specified list of identifiers as the argument
    160   /// list for this macro.
    161   void setArgumentList(IdentifierInfo* const *List, unsigned NumArgs,
    162                        llvm::BumpPtrAllocator &PPAllocator) {
    163     assert(ArgumentList == 0 && NumArguments == 0 &&
    164            "Argument list already set!");
    165     if (NumArgs == 0) return;
    166 
    167     NumArguments = NumArgs;
    168     ArgumentList = PPAllocator.Allocate<IdentifierInfo*>(NumArgs);
    169     for (unsigned i = 0; i != NumArgs; ++i)
    170       ArgumentList[i] = List[i];
    171   }
    172 
    173   /// Arguments - The list of arguments for a function-like macro.  This can be
    174   /// empty, for, e.g. "#define X()".
    175   typedef IdentifierInfo* const *arg_iterator;
    176   bool arg_empty() const { return NumArguments == 0; }
    177   arg_iterator arg_begin() const { return ArgumentList; }
    178   arg_iterator arg_end() const { return ArgumentList+NumArguments; }
    179   unsigned getNumArgs() const { return NumArguments; }
    180 
    181   /// getArgumentNum - Return the argument number of the specified identifier,
    182   /// or -1 if the identifier is not a formal argument identifier.
    183   int getArgumentNum(IdentifierInfo *Arg) const {
    184     for (arg_iterator I = arg_begin(), E = arg_end(); I != E; ++I)
    185       if (*I == Arg) return I-arg_begin();
    186     return -1;
    187   }
    188 
    189   /// Function/Object-likeness.  Keep track of whether this macro has formal
    190   /// parameters.
    191   void setIsFunctionLike() { IsFunctionLike = true; }
    192   bool isFunctionLike() const { return IsFunctionLike; }
    193   bool isObjectLike() const { return !IsFunctionLike; }
    194 
    195   /// Varargs querying methods.  This can only be set for function-like macros.
    196   void setIsC99Varargs() { IsC99Varargs = true; }
    197   void setIsGNUVarargs() { IsGNUVarargs = true; }
    198   bool isC99Varargs() const { return IsC99Varargs; }
    199   bool isGNUVarargs() const { return IsGNUVarargs; }
    200   bool isVariadic() const { return IsC99Varargs | IsGNUVarargs; }
    201 
    202   /// isBuiltinMacro - Return true if this macro is a builtin macro, such as
    203   /// __LINE__, which requires processing before expansion.
    204   bool isBuiltinMacro() const { return IsBuiltinMacro; }
    205 
    206   /// isFromAST - Return true if this macro was loaded from an AST file.
    207   bool isFromAST() const { return IsFromAST; }
    208 
    209   /// setIsFromAST - Set whether this macro was loaded from an AST file.
    210   void setIsFromAST(bool FromAST = true) { IsFromAST = FromAST; }
    211 
    212   /// isUsed - Return false if this macro is defined in the main file and has
    213   /// not yet been used.
    214   bool isUsed() const { return IsUsed; }
    215 
    216   /// isAllowRedefinitionsWithoutWarning - Return true if this macro can be
    217   /// redefined without warning.
    218   bool isAllowRedefinitionsWithoutWarning() const {
    219     return IsAllowRedefinitionsWithoutWarning;
    220   }
    221 
    222   /// \brief Return true if we should emit a warning if the macro is unused.
    223   bool isWarnIfUnused() const {
    224     return IsWarnIfUnused;
    225   }
    226 
    227   /// getNumTokens - Return the number of tokens that this macro expands to.
    228   ///
    229   unsigned getNumTokens() const {
    230     return ReplacementTokens.size();
    231   }
    232 
    233   const Token &getReplacementToken(unsigned Tok) const {
    234     assert(Tok < ReplacementTokens.size() && "Invalid token #");
    235     return ReplacementTokens[Tok];
    236   }
    237 
    238   typedef llvm::SmallVector<Token, 8>::const_iterator tokens_iterator;
    239   tokens_iterator tokens_begin() const { return ReplacementTokens.begin(); }
    240   tokens_iterator tokens_end() const { return ReplacementTokens.end(); }
    241   bool tokens_empty() const { return ReplacementTokens.empty(); }
    242 
    243   /// AddTokenToBody - Add the specified token to the replacement text for the
    244   /// macro.
    245   void AddTokenToBody(const Token &Tok) {
    246     assert(!IsDefinitionLengthCached &&
    247           "Changing replacement tokens after definition length got calculated");
    248     ReplacementTokens.push_back(Tok);
    249   }
    250 
    251   /// isEnabled - Return true if this macro is enabled: in other words, that we
    252   /// are not currently in an expansion of this macro.
    253   bool isEnabled() const { return !IsDisabled; }
    254 
    255   void EnableMacro() {
    256     assert(IsDisabled && "Cannot enable an already-enabled macro!");
    257     IsDisabled = false;
    258   }
    259 
    260   void DisableMacro() {
    261     assert(!IsDisabled && "Cannot disable an already-disabled macro!");
    262     IsDisabled = true;
    263   }
    264 
    265 private:
    266   unsigned getDefinitionLengthSlow(SourceManager &SM) const;
    267 };
    268 
    269 }  // end namespace clang
    270 
    271 #endif
    272