text: //===--- Comment.cpp - Comment AST node implementation --------------------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  
  #include "clang/AST/Comment.h"
  #include "clang/AST/ASTContext.h"
  #include "clang/AST/Decl.h"
  #include "clang/AST/DeclObjC.h"
  #include "clang/AST/DeclTemplate.h"
  #include "clang/Basic/CharInfo.h"
  #include "llvm/Support/ErrorHandling.h"
  
  namespace clang {
  namespace comments {
  
  const char *Comment::getCommentKindName() const {
    switch (getCommentKind()) {
    case NoCommentKind: return "NoCommentKind";
  #define ABSTRACT_COMMENT(COMMENT)
  #define COMMENT(CLASS, PARENT) \
    case CLASS##Kind: \
      return #CLASS;
  #include "clang/AST/CommentNodes.inc"
  #undef COMMENT
  #undef ABSTRACT_COMMENT
    }
    llvm_unreachable("Unknown comment kind!");
  }
  
  namespace {
  struct good {};
  struct bad {};
  
  template <typename T>
  good implements_child_begin_end(Comment::child_iterator (T::*)() const) {
    return good();
  }
  
  LLVM_ATTRIBUTE_UNUSED
  static inline bad implements_child_begin_end(
                        Comment::child_iterator (Comment::*)() const) {
    return bad();
  }
  
  #define ASSERT_IMPLEMENTS_child_begin(function) \
    (void) good(implements_child_begin_end(function))
  
  LLVM_ATTRIBUTE_UNUSED
  static inline void CheckCommentASTNodes() {
  #define ABSTRACT_COMMENT(COMMENT)
  #define COMMENT(CLASS, PARENT) \
    ASSERT_IMPLEMENTS_child_begin(&CLASS::child_begin); \
    ASSERT_IMPLEMENTS_child_begin(&CLASS::child_end);
  #include "clang/AST/CommentNodes.inc"
  #undef COMMENT
  #undef ABSTRACT_COMMENT
  }
  
  #undef ASSERT_IMPLEMENTS_child_begin
  
  } // end unnamed namespace
  
  Comment::child_iterator Comment::child_begin() const {
    switch (getCommentKind()) {
    case NoCommentKind: llvm_unreachable("comment without a kind");
  #define ABSTRACT_COMMENT(COMMENT)
  #define COMMENT(CLASS, PARENT) \
    case CLASS##Kind: \
      return static_cast<const CLASS *>(this)->child_begin();
  #include "clang/AST/CommentNodes.inc"
  #undef COMMENT
  #undef ABSTRACT_COMMENT
    }
    llvm_unreachable("Unknown comment kind!");
  }
  
  Comment::child_iterator Comment::child_end() const {
    switch (getCommentKind()) {
    case NoCommentKind: llvm_unreachable("comment without a kind");
  #define ABSTRACT_COMMENT(COMMENT)
  #define COMMENT(CLASS, PARENT) \
    case CLASS##Kind: \
      return static_cast<const CLASS *>(this)->child_end();
  #include "clang/AST/CommentNodes.inc"
  #undef COMMENT
  #undef ABSTRACT_COMMENT
    }
    llvm_unreachable("Unknown comment kind!");
  }
  
  bool TextComment::isWhitespaceNoCache() const {
    for (StringRef::const_iterator I = Text.begin(), E = Text.end();
         I != E; ++I) {
      if (!clang::isWhitespace(*I))
        return false;
    }
    return true;
  }
  
  bool ParagraphComment::isWhitespaceNoCache() const {
    for (child_iterator I = child_begin(), E = child_end(); I != E; ++I) {
      if (const TextComment *TC = dyn_cast<TextComment>(*I)) {
        if (!TC->isWhitespace())
          return false;
      } else
        return false;
    }
    return true;
  }
  
  static TypeLoc lookThroughTypedefOrTypeAliasLocs(TypeLoc &SrcTL) {
    TypeLoc TL = SrcTL.IgnoreParens();
  
    // Look through attribute types.
    if (AttributedTypeLoc AttributeTL = TL.getAs<AttributedTypeLoc>())
      return AttributeTL.getModifiedLoc();
    // Look through qualified types.
    if (QualifiedTypeLoc QualifiedTL = TL.getAs<QualifiedTypeLoc>())
      return QualifiedTL.getUnqualifiedLoc();
    // Look through pointer types.
    if (PointerTypeLoc PointerTL = TL.getAs<PointerTypeLoc>())
      return PointerTL.getPointeeLoc().getUnqualifiedLoc();
    // Look through reference types.
    if (ReferenceTypeLoc ReferenceTL = TL.getAs<ReferenceTypeLoc>())
      return ReferenceTL.getPointeeLoc().getUnqualifiedLoc();
    // Look through adjusted types.
    if (AdjustedTypeLoc ATL = TL.getAs<AdjustedTypeLoc>())
      return ATL.getOriginalLoc();
    if (BlockPointerTypeLoc BlockPointerTL = TL.getAs<BlockPointerTypeLoc>())
      return BlockPointerTL.getPointeeLoc().getUnqualifiedLoc();
    if (MemberPointerTypeLoc MemberPointerTL = TL.getAs<MemberPointerTypeLoc>())
      return MemberPointerTL.getPointeeLoc().getUnqualifiedLoc();
    if (ElaboratedTypeLoc ETL = TL.getAs<ElaboratedTypeLoc>())
      return ETL.getNamedTypeLoc();
  
    return TL;
  }
  
  static bool getFunctionTypeLoc(TypeLoc TL, FunctionTypeLoc &ResFTL) {
    TypeLoc PrevTL;
    while (PrevTL != TL) {
      PrevTL = TL;
      TL = lookThroughTypedefOrTypeAliasLocs(TL);
    }
  
    if (FunctionTypeLoc FTL = TL.getAs<FunctionTypeLoc>()) {
      ResFTL = FTL;
      return true;
    }
  
    if (TemplateSpecializationTypeLoc STL =
            TL.getAs<TemplateSpecializationTypeLoc>()) {
      // If we have a typedef to a template specialization with exactly one
      // template argument of a function type, this looks like std::function,
      // boost::function, or other function wrapper.  Treat these typedefs as
      // functions.
      if (STL.getNumArgs() != 1)
        return false;
      TemplateArgumentLoc MaybeFunction = STL.getArgLoc(0);
      if (MaybeFunction.getArgument().getKind() != TemplateArgument::Type)
        return false;
      TypeSourceInfo *MaybeFunctionTSI = MaybeFunction.getTypeSourceInfo();
      TypeLoc TL = MaybeFunctionTSI->getTypeLoc().getUnqualifiedLoc();
      if (FunctionTypeLoc FTL = TL.getAs<FunctionTypeLoc>()) {
        ResFTL = FTL;
        return true;
      }
    }
  
    return false;
  }
  
  const char *ParamCommandComment::getDirectionAsString(PassDirection D) {
    switch (D) {
    case ParamCommandComment::In:
      return "[in]";
    case ParamCommandComment::Out:
      return "[out]";
    case ParamCommandComment::InOut:
      return "[in,out]";
    }
    llvm_unreachable("unknown PassDirection");
  }
  
  void DeclInfo::fill() {
    assert(!IsFilled);
  
    // Set defaults.
    Kind = OtherKind;
    TemplateKind = NotTemplate;
    IsObjCMethod = false;
    IsInstanceMethod = false;
    IsClassMethod = false;
    ParamVars = None;
    TemplateParameters = nullptr;
  
    if (!CommentDecl) {
      // If there is no declaration, the defaults is our only guess.
      IsFilled = true;
      return;
    }
    CurrentDecl = CommentDecl;
  
    Decl::Kind K = CommentDecl->getKind();
    switch (K) {
    default:
      // Defaults are should be good for declarations we don't handle explicitly.
      break;
    case Decl::Function:
    case Decl::CXXMethod:
    case Decl::CXXConstructor:
    case Decl::CXXDestructor:
    case Decl::CXXConversion: {
      const FunctionDecl *FD = cast<FunctionDecl>(CommentDecl);
      Kind = FunctionKind;
      ParamVars = FD->parameters();
      ReturnType = FD->getReturnType();
      unsigned NumLists = FD->getNumTemplateParameterLists();
      if (NumLists != 0) {
        TemplateKind = TemplateSpecialization;
        TemplateParameters =
            FD->getTemplateParameterList(NumLists - 1);
      }
  
      if (K == Decl::CXXMethod || K == Decl::CXXConstructor ||
          K == Decl::CXXDestructor || K == Decl::CXXConversion) {
        const CXXMethodDecl *MD = cast<CXXMethodDecl>(CommentDecl);
        IsInstanceMethod = MD->isInstance();
        IsClassMethod = !IsInstanceMethod;
      }
      break;
    }
    case Decl::ObjCMethod: {
      const ObjCMethodDecl *MD = cast<ObjCMethodDecl>(CommentDecl);
      Kind = FunctionKind;
      ParamVars = MD->parameters();
      ReturnType = MD->getReturnType();
      IsObjCMethod = true;
      IsInstanceMethod = MD->isInstanceMethod();
      IsClassMethod = !IsInstanceMethod;
      break;
    }
    case Decl::FunctionTemplate: {
      const FunctionTemplateDecl *FTD = cast<FunctionTemplateDecl>(CommentDecl);
      Kind = FunctionKind;
      TemplateKind = Template;
      const FunctionDecl *FD = FTD->getTemplatedDecl();
      ParamVars = FD->parameters();
      ReturnType = FD->getReturnType();
      TemplateParameters = FTD->getTemplateParameters();
      break;
    }
    case Decl::ClassTemplate: {
      const ClassTemplateDecl *CTD = cast<ClassTemplateDecl>(CommentDecl);
      Kind = ClassKind;
      TemplateKind = Template;
      TemplateParameters = CTD->getTemplateParameters();
      break;
    }
    case Decl::ClassTemplatePartialSpecialization: {
      const ClassTemplatePartialSpecializationDecl *CTPSD =
          cast<ClassTemplatePartialSpecializationDecl>(CommentDecl);
      Kind = ClassKind;
      TemplateKind = TemplatePartialSpecialization;
      TemplateParameters = CTPSD->getTemplateParameters();
      break;
    }
    case Decl::ClassTemplateSpecialization:
      Kind = ClassKind;
      TemplateKind = TemplateSpecialization;
      break;
    case Decl::Record:
    case Decl::CXXRecord:
      Kind = ClassKind;
      break;
    case Decl::Var:
    case Decl::Field:
    case Decl::EnumConstant:
    case Decl::ObjCIvar:
    case Decl::ObjCAtDefsField:
    case Decl::ObjCProperty: {
      const TypeSourceInfo *TSI;
      if (const auto *VD = dyn_cast<DeclaratorDecl>(CommentDecl))
        TSI = VD->getTypeSourceInfo();
      else if (const auto *PD = dyn_cast<ObjCPropertyDecl>(CommentDecl))
        TSI = PD->getTypeSourceInfo();
      else
        TSI = nullptr;
      if (TSI) {
        TypeLoc TL = TSI->getTypeLoc().getUnqualifiedLoc();
        FunctionTypeLoc FTL;
        if (getFunctionTypeLoc(TL, FTL)) {
          ParamVars = FTL.getParams();
          ReturnType = FTL.getReturnLoc().getType();
        }
      }
      Kind = VariableKind;
      break;
    }
    case Decl::Namespace:
      Kind = NamespaceKind;
      break;
    case Decl::TypeAlias:
    case Decl::Typedef: {
      Kind = TypedefKind;
      // If this is a typedef / using to something we consider a function, extract
      // arguments and return type.
      const TypeSourceInfo *TSI =
          K == Decl::Typedef
              ? cast<TypedefDecl>(CommentDecl)->getTypeSourceInfo()
              : cast<TypeAliasDecl>(CommentDecl)->getTypeSourceInfo();
      if (!TSI)
        break;
      TypeLoc TL = TSI->getTypeLoc().getUnqualifiedLoc();
      FunctionTypeLoc FTL;
      if (getFunctionTypeLoc(TL, FTL)) {
        Kind = FunctionKind;
        ParamVars = FTL.getParams();
        ReturnType = FTL.getReturnLoc().getType();
      }
      break;
    }
    case Decl::TypeAliasTemplate: {
      const TypeAliasTemplateDecl *TAT = cast<TypeAliasTemplateDecl>(CommentDecl);
      Kind = TypedefKind;
      TemplateKind = Template;
      TemplateParameters = TAT->getTemplateParameters();
      TypeAliasDecl *TAD = TAT->getTemplatedDecl();
      if (!TAD)
        break;
  
      const TypeSourceInfo *TSI = TAD->getTypeSourceInfo();
      if (!TSI)
        break;
      TypeLoc TL = TSI->getTypeLoc().getUnqualifiedLoc();
      FunctionTypeLoc FTL;
      if (getFunctionTypeLoc(TL, FTL)) {
        Kind = FunctionKind;
        ParamVars = FTL.getParams();
        ReturnType = FTL.getReturnLoc().getType();
      }
      break;
    }
    case Decl::Enum:
      Kind = EnumKind;
      break;
    }
  
    IsFilled = true;
  }
  
  StringRef ParamCommandComment::getParamName(const FullComment *FC) const {
    assert(isParamIndexValid());
    if (isVarArgParam())
      return "...";
    return FC->getDeclInfo()->ParamVars[getParamIndex()]->getName();
  }
  
  StringRef TParamCommandComment::getParamName(const FullComment *FC) const {
    assert(isPositionValid());
    const TemplateParameterList *TPL = FC->getDeclInfo()->TemplateParameters;
    for (unsigned i = 0, e = getDepth(); i != e; ++i) {
      if (i == e-1)
        return TPL->getParam(getIndex(i))->getName();
      const NamedDecl *Param = TPL->getParam(getIndex(i));
      if (const TemplateTemplateParmDecl *TTP =
            dyn_cast<TemplateTemplateParmDecl>(Param))
        TPL = TTP->getTemplateParameters();
    }
    return "";
  }
  
  } // end namespace comments
  } // end namespace clang
  
  