C++ method_iterator::getCanonicalDecl方法代码示例

void FinalOverriderCollector::Collect(const CXXRecordDecl *RD, 
                                      bool VirtualBase,
                                      const CXXRecordDecl *InVirtualSubobject,
                                      CXXFinalOverriderMap &Overriders) {
  unsigned SubobjectNumber = 0;
  if (!VirtualBase)
    SubobjectNumber
      = ++SubobjectCount[cast<CXXRecordDecl>(RD->getCanonicalDecl())];

  for (CXXRecordDecl::base_class_const_iterator Base = RD->bases_begin(),
         BaseEnd = RD->bases_end(); Base != BaseEnd; ++Base) {
    if (const RecordType *RT = Base->getType()->getAs<RecordType>()) {
      const CXXRecordDecl *BaseDecl = cast<CXXRecordDecl>(RT->getDecl());
      if (!BaseDecl->isPolymorphic())
        continue;

      if (Overriders.empty() && !Base->isVirtual()) {
        // There are no other overriders of virtual member functions,
        // so let the base class fill in our overriders for us.
        Collect(BaseDecl, false, InVirtualSubobject, Overriders);
        continue;
      }

      // Collect all of the overridders from the base class subobject
      // and merge them into the set of overridders for this class.
      // For virtual base classes, populate or use the cached virtual
      // overrides so that we do not walk the virtual base class (and
      // its base classes) more than once.
      CXXFinalOverriderMap ComputedBaseOverriders;
      CXXFinalOverriderMap *BaseOverriders = &ComputedBaseOverriders;
      if (Base->isVirtual()) {
        CXXFinalOverriderMap *&MyVirtualOverriders = VirtualOverriders[BaseDecl];
        BaseOverriders = MyVirtualOverriders;
        if (!MyVirtualOverriders) {
          MyVirtualOverriders = new CXXFinalOverriderMap;

          // Collect may cause VirtualOverriders to reallocate, invalidating the
          // MyVirtualOverriders reference. Set BaseOverriders to the right
          // value now.
          BaseOverriders = MyVirtualOverriders;

          Collect(BaseDecl, true, BaseDecl, *MyVirtualOverriders);
        }
      } else
        Collect(BaseDecl, false, InVirtualSubobject, ComputedBaseOverriders);

      // Merge the overriders from this base class into our own set of
      // overriders.
      for (CXXFinalOverriderMap::iterator OM = BaseOverriders->begin(), 
                               OMEnd = BaseOverriders->end();
           OM != OMEnd;
           ++OM) {
        const CXXMethodDecl *CanonOM
          = cast<CXXMethodDecl>(OM->first->getCanonicalDecl());
        Overriders[CanonOM].add(OM->second);
      }
    }
  }

  for (CXXRecordDecl::method_iterator M = RD->method_begin(), 
                                   MEnd = RD->method_end();
       M != MEnd;
       ++M) {
    // We only care about virtual methods.
    if (!M->isVirtual())
      continue;

    CXXMethodDecl *CanonM = cast<CXXMethodDecl>(M->getCanonicalDecl());

    if (CanonM->begin_overridden_methods()
                                       == CanonM->end_overridden_methods()) {
      // This is a new virtual function that does not override any
      // other virtual function. Add it to the map of virtual
      // functions for which we are tracking overridders. 

      // C++ [class.virtual]p2:
      //   For convenience we say that any virtual function overrides itself.
      Overriders[CanonM].add(SubobjectNumber,
                             UniqueVirtualMethod(CanonM, SubobjectNumber,
                                                 InVirtualSubobject));
      continue;
    }

    // This virtual method overrides other virtual methods, so it does
    // not add any new slots into the set of overriders. Instead, we
    // replace entries in the set of overriders with the new
    // overrider. To do so, we dig down to the original virtual
    // functions using data recursion and update all of the methods it
    // overrides.
    typedef std::pair<CXXMethodDecl::method_iterator, 
                      CXXMethodDecl::method_iterator> OverriddenMethods;
    SmallVector<OverriddenMethods, 4> Stack;
    Stack.push_back(std::make_pair(CanonM->begin_overridden_methods(),
                                   CanonM->end_overridden_methods()));
    while (!Stack.empty()) {
      OverriddenMethods OverMethods = Stack.back();
      Stack.pop_back();

      for (; OverMethods.first != OverMethods.second; ++OverMethods.first) {
        const CXXMethodDecl *CanonOM
//.........这里部分代码省略.........