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      1 //===--- MacroInfo.cpp - Information about #defined identifiers -----------===//
      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 implements the MacroInfo interface.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "clang/Lex/MacroInfo.h"
     15 #include "clang/Lex/Preprocessor.h"
     16 using namespace clang;
     17 
     18 MacroInfo::MacroInfo(SourceLocation DefLoc)
     19   : Location(DefLoc),
     20     ArgumentList(nullptr),
     21     NumArguments(0),
     22     IsDefinitionLengthCached(false),
     23     IsFunctionLike(false),
     24     IsC99Varargs(false),
     25     IsGNUVarargs(false),
     26     IsBuiltinMacro(false),
     27     HasCommaPasting(false),
     28     IsDisabled(false),
     29     IsUsed(false),
     30     IsAllowRedefinitionsWithoutWarning(false),
     31     IsWarnIfUnused(false),
     32     FromASTFile(false),
     33     UsedForHeaderGuard(false) {
     34 }
     35 
     36 unsigned MacroInfo::getDefinitionLengthSlow(SourceManager &SM) const {
     37   assert(!IsDefinitionLengthCached);
     38   IsDefinitionLengthCached = true;
     39 
     40   if (ReplacementTokens.empty())
     41     return (DefinitionLength = 0);
     42 
     43   const Token &firstToken = ReplacementTokens.front();
     44   const Token &lastToken = ReplacementTokens.back();
     45   SourceLocation macroStart = firstToken.getLocation();
     46   SourceLocation macroEnd = lastToken.getLocation();
     47   assert(macroStart.isValid() && macroEnd.isValid());
     48   assert((macroStart.isFileID() || firstToken.is(tok::comment)) &&
     49          "Macro defined in macro?");
     50   assert((macroEnd.isFileID() || lastToken.is(tok::comment)) &&
     51          "Macro defined in macro?");
     52   std::pair<FileID, unsigned>
     53       startInfo = SM.getDecomposedExpansionLoc(macroStart);
     54   std::pair<FileID, unsigned>
     55       endInfo = SM.getDecomposedExpansionLoc(macroEnd);
     56   assert(startInfo.first == endInfo.first &&
     57          "Macro definition spanning multiple FileIDs ?");
     58   assert(startInfo.second <= endInfo.second);
     59   DefinitionLength = endInfo.second - startInfo.second;
     60   DefinitionLength += lastToken.getLength();
     61 
     62   return DefinitionLength;
     63 }
     64 
     65 /// \brief Return true if the specified macro definition is equal to
     66 /// this macro in spelling, arguments, and whitespace.
     67 ///
     68 /// \param Syntactically if true, the macro definitions can be identical even
     69 /// if they use different identifiers for the function macro parameters.
     70 /// Otherwise the comparison is lexical and this implements the rules in
     71 /// C99 6.10.3.
     72 bool MacroInfo::isIdenticalTo(const MacroInfo &Other, Preprocessor &PP,
     73                               bool Syntactically) const {
     74   bool Lexically = !Syntactically;
     75 
     76   // Check # tokens in replacement, number of args, and various flags all match.
     77   if (ReplacementTokens.size() != Other.ReplacementTokens.size() ||
     78       getNumArgs() != Other.getNumArgs() ||
     79       isFunctionLike() != Other.isFunctionLike() ||
     80       isC99Varargs() != Other.isC99Varargs() ||
     81       isGNUVarargs() != Other.isGNUVarargs())
     82     return false;
     83 
     84   if (Lexically) {
     85     // Check arguments.
     86     for (arg_iterator I = arg_begin(), OI = Other.arg_begin(), E = arg_end();
     87          I != E; ++I, ++OI)
     88       if (*I != *OI) return false;
     89   }
     90 
     91   // Check all the tokens.
     92   for (unsigned i = 0, e = ReplacementTokens.size(); i != e; ++i) {
     93     const Token &A = ReplacementTokens[i];
     94     const Token &B = Other.ReplacementTokens[i];
     95     if (A.getKind() != B.getKind())
     96       return false;
     97 
     98     // If this isn't the first first token, check that the whitespace and
     99     // start-of-line characteristics match.
    100     if (i != 0 &&
    101         (A.isAtStartOfLine() != B.isAtStartOfLine() ||
    102          A.hasLeadingSpace() != B.hasLeadingSpace()))
    103       return false;
    104 
    105     // If this is an identifier, it is easy.
    106     if (A.getIdentifierInfo() || B.getIdentifierInfo()) {
    107       if (A.getIdentifierInfo() == B.getIdentifierInfo())
    108         continue;
    109       if (Lexically)
    110         return false;
    111       // With syntactic equivalence the parameter names can be different as long
    112       // as they are used in the same place.
    113       int AArgNum = getArgumentNum(A.getIdentifierInfo());
    114       if (AArgNum == -1)
    115         return false;
    116       if (AArgNum != Other.getArgumentNum(B.getIdentifierInfo()))
    117         return false;
    118       continue;
    119     }
    120 
    121     // Otherwise, check the spelling.
    122     if (PP.getSpelling(A) != PP.getSpelling(B))
    123       return false;
    124   }
    125 
    126   return true;
    127 }
    128 
    129 MacroDirective::DefInfo MacroDirective::getDefinition() {
    130   MacroDirective *MD = this;
    131   SourceLocation UndefLoc;
    132   Optional<bool> isPublic;
    133   for (; MD; MD = MD->getPrevious()) {
    134     if (DefMacroDirective *DefMD = dyn_cast<DefMacroDirective>(MD))
    135       return DefInfo(DefMD, UndefLoc,
    136                      !isPublic.hasValue() || isPublic.getValue());
    137 
    138     if (UndefMacroDirective *UndefMD = dyn_cast<UndefMacroDirective>(MD)) {
    139       UndefLoc = UndefMD->getLocation();
    140       continue;
    141     }
    142 
    143     VisibilityMacroDirective *VisMD = cast<VisibilityMacroDirective>(MD);
    144     if (!isPublic.hasValue())
    145       isPublic = VisMD->isPublic();
    146   }
    147 
    148   return DefInfo(nullptr, UndefLoc,
    149                  !isPublic.hasValue() || isPublic.getValue());
    150 }
    151 
    152 const MacroDirective::DefInfo
    153 MacroDirective::findDirectiveAtLoc(SourceLocation L, SourceManager &SM) const {
    154   assert(L.isValid() && "SourceLocation is invalid.");
    155   for (DefInfo Def = getDefinition(); Def; Def = Def.getPreviousDefinition()) {
    156     if (Def.getLocation().isInvalid() ||  // For macros defined on the command line.
    157         SM.isBeforeInTranslationUnit(Def.getLocation(), L))
    158       return (!Def.isUndefined() ||
    159               SM.isBeforeInTranslationUnit(L, Def.getUndefLocation()))
    160                   ? Def : DefInfo();
    161   }
    162   return DefInfo();
    163 }
    164