Coverage Report

Created: 2020-02-15 09:57

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/AST/ItaniumCXXABI.cpp
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//===------- ItaniumCXXABI.cpp - AST support for the Itanium C++ ABI ------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This provides C++ AST support targeting the Itanium C++ ABI, which is
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// documented at:
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//  http://www.codesourcery.com/public/cxx-abi/abi.html
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//  http://www.codesourcery.com/public/cxx-abi/abi-eh.html
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//
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// It also supports the closely-related ARM C++ ABI, documented at:
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// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf
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//
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//===----------------------------------------------------------------------===//
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#include "CXXABI.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/AST/Mangle.h"
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#include "clang/AST/MangleNumberingContext.h"
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#include "clang/AST/RecordLayout.h"
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#include "clang/AST/Type.h"
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#include "clang/Basic/TargetInfo.h"
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#include "llvm/ADT/FoldingSet.h"
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#include "llvm/ADT/iterator.h"
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using namespace clang;
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namespace {
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/// According to Itanium C++ ABI 5.1.2:
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/// the name of an anonymous union is considered to be
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/// the name of the first named data member found by a pre-order,
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/// depth-first, declaration-order walk of the data members of
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/// the anonymous union.
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/// If there is no such data member (i.e., if all of the data members
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/// in the union are unnamed), then there is no way for a program to
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/// refer to the anonymous union, and there is therefore no need to mangle its name.
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///
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/// Returns the name of anonymous union VarDecl or nullptr if it is not found.
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static const IdentifierInfo *findAnonymousUnionVarDeclName(const VarDecl& VD) {
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  const RecordType *RT = VD.getType()->getAs<RecordType>();
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  assert(RT && "type of VarDecl is expected to be RecordType.");
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  assert(RT->getDecl()->isUnion() && "RecordType is expected to be a union.");
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  if (const FieldDecl *FD = RT->getDecl()->findFirstNamedDataMember()) {
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    return FD->getIdentifier();
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  }
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1
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  return nullptr;
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1
}
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/// The name of a decomposition declaration.
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struct DecompositionDeclName {
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  using BindingArray = ArrayRef<const BindingDecl*>;
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  /// Representative example of a set of bindings with these names.
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  BindingArray Bindings;
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  /// Iterators over the sequence of identifiers in the name.
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  struct Iterator
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      : llvm::iterator_adaptor_base<Iterator, BindingArray::const_iterator,
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                                    std::random_access_iterator_tag,
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                                    const IdentifierInfo *> {
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2
    Iterator(BindingArray::const_iterator It) : iterator_adaptor_base(It) {}
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1
    const IdentifierInfo *operator*() const {
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1
      return (*this->I)->getIdentifier();
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1
    }
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  };
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  Iterator begin() const { return Iterator(Bindings.begin()); }
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1
  Iterator end() const { return Iterator(Bindings.end()); }
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};
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}
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namespace llvm {
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template<typename T> bool isDenseMapKeyEmpty(T V) {
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  return llvm::DenseMapInfo<T>::isEqual(
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      V, llvm::DenseMapInfo<T>::getEmptyKey());
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}
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template<typename T> bool isDenseMapKeyTombstone(T V) {
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  return llvm::DenseMapInfo<T>::isEqual(
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      V, llvm::DenseMapInfo<T>::getTombstoneKey());
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}
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template<typename T>
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Optional<bool> areDenseMapKeysEqualSpecialValues(T LHS, T RHS) {
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  bool LHSEmpty = isDenseMapKeyEmpty(LHS);
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  bool RHSEmpty = isDenseMapKeyEmpty(RHS);
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  if (LHSEmpty || 
RHSEmpty7
)
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    return LHSEmpty && 
RHSEmpty65
;
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3
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  bool LHSTombstone = isDenseMapKeyTombstone(LHS);
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  bool RHSTombstone = isDenseMapKeyTombstone(RHS);
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  if (LHSTombstone || RHSTombstone)
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    return LHSTombstone && 
RHSTombstone0
;
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0
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  return None;
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0
}
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template<>
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struct DenseMapInfo<DecompositionDeclName> {
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  using ArrayInfo = llvm::DenseMapInfo<ArrayRef<const BindingDecl*>>;
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  static DecompositionDeclName getEmptyKey() {
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    return {ArrayInfo::getEmptyKey()};
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  }
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  static DecompositionDeclName getTombstoneKey() {
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    return {ArrayInfo::getTombstoneKey()};
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  }
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  static unsigned getHashValue(DecompositionDeclName Key) {
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    assert(!isEqual(Key, getEmptyKey()) && !isEqual(Key, getTombstoneKey()));
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    return llvm::hash_combine_range(Key.begin(), Key.end());
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  }
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  static bool isEqual(DecompositionDeclName LHS, DecompositionDeclName RHS) {
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    if (Optional<bool> Result = areDenseMapKeysEqualSpecialValues(
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            LHS.Bindings, RHS.Bindings))
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      return *Result;
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    return LHS.Bindings.size() == RHS.Bindings.size() &&
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           std::equal(LHS.begin(), LHS.end(), RHS.begin());
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  }
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};
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}
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namespace {
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/// Keeps track of the mangled names of lambda expressions and block
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/// literals within a particular context.
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class ItaniumNumberingContext : public MangleNumberingContext {
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  ItaniumMangleContext *Mangler;
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  llvm::StringMap<unsigned> LambdaManglingNumbers;
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  unsigned BlockManglingNumber = 0;
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  llvm::DenseMap<const IdentifierInfo *, unsigned> VarManglingNumbers;
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  llvm::DenseMap<const IdentifierInfo *, unsigned> TagManglingNumbers;
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  llvm::DenseMap<DecompositionDeclName, unsigned>
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      DecompsitionDeclManglingNumbers;
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public:
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33.0k
  ItaniumNumberingContext(ItaniumMangleContext *Mangler) : Mangler(Mangler) {}
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  unsigned getManglingNumber(const CXXMethodDecl *CallOperator) override {
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    const CXXRecordDecl *Lambda = CallOperator->getParent();
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    assert(Lambda->isLambda());
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    // Computation of the <lambda-sig> is non-trivial and subtle. Rather than
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    // duplicating it here, just mangle the <lambda-sig> directly.
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    llvm::SmallString<128> LambdaSig;
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    llvm::raw_svector_ostream Out(LambdaSig);
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    Mangler->mangleLambdaSig(Lambda, Out);
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    return ++LambdaManglingNumbers[LambdaSig];
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  }
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  unsigned getManglingNumber(const BlockDecl *BD) override {
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    return ++BlockManglingNumber;
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  }
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  unsigned getStaticLocalNumber(const VarDecl *VD) override {
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    return 0;
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  }
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  /// Variable decls are numbered by identifier.
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3.89k
  unsigned getManglingNumber(const VarDecl *VD, unsigned) override {
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3.89k
    if (auto *DD = dyn_cast<DecompositionDecl>(VD)) {
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      DecompositionDeclName Name{DD->bindings()};
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      return ++DecompsitionDeclManglingNumbers[Name];
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    }
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    const IdentifierInfo *Identifier = VD->getIdentifier();
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    if (!Identifier) {
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      // VarDecl without an identifier represents an anonymous union
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      // declaration.
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      Identifier = findAnonymousUnionVarDeclName(*VD);
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    }
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    return ++VarManglingNumbers[Identifier];
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  }
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  unsigned getManglingNumber(const TagDecl *TD, unsigned) override {
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    return ++TagManglingNumbers[TD->getIdentifier()];
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  }
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};
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class ItaniumCXXABI : public CXXABI {
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private:
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  std::unique_ptr<MangleContext> Mangler;
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protected:
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  ASTContext &Context;
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public:
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  ItaniumCXXABI(ASTContext &Ctx)
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      : Mangler(Ctx.createMangleContext()), Context(Ctx) {}
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  MemberPointerInfo
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  getMemberPointerInfo(const MemberPointerType *MPT) const override {
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    const TargetInfo &Target = Context.getTargetInfo();
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    TargetInfo::IntType PtrDiff = Target.getPtrDiffType(0);
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    MemberPointerInfo MPI;
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    MPI.Width = Target.getTypeWidth(PtrDiff);
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    MPI.Align = Target.getTypeAlign(PtrDiff);
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    MPI.HasPadding = false;
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    if (MPT->isMemberFunctionPointer())
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      MPI.Width *= 2;
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    return MPI;
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  }
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1.92M
  CallingConv getDefaultMethodCallConv(bool isVariadic) const override {
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1.92M
    const llvm::Triple &T = Context.getTargetInfo().getTriple();
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1.92M
    if (!isVariadic && 
T.isWindowsGNUEnvironment()1.90M
&&
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1.92M
        
T.getArch() == llvm::Triple::x867.23k
)
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      return CC_X86ThisCall;
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    return Context.getTargetInfo().getDefaultCallingConv();
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  }
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  // We cheat and just check that the class has a vtable pointer, and that it's
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  // only big enough to have a vtable pointer and nothing more (or less).
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  bool isNearlyEmpty(const CXXRecordDecl *RD) const override {
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    // Check that the class has a vtable pointer.
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    if (!RD->isDynamicClass())
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      return false;
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    const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
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    CharUnits PointerSize =
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      Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
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    return Layout.getNonVirtualSize() == PointerSize;
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  }
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  const CXXConstructorDecl *
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  getCopyConstructorForExceptionObject(CXXRecordDecl *RD) override {
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    return nullptr;
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  }
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  void addCopyConstructorForExceptionObject(CXXRecordDecl *RD,
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                                            CXXConstructorDecl *CD) override {}
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  void addTypedefNameForUnnamedTagDecl(TagDecl *TD,
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                                       TypedefNameDecl *DD) override {}
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708k
  TypedefNameDecl *getTypedefNameForUnnamedTagDecl(const TagDecl *TD) override {
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    return nullptr;
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  }
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  void addDeclaratorForUnnamedTagDecl(TagDecl *TD,
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                                      DeclaratorDecl *DD) override {}
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708k
  DeclaratorDecl *getDeclaratorForUnnamedTagDecl(const TagDecl *TD) override {
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    return nullptr;
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  }
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  std::unique_ptr<MangleNumberingContext>
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33.0k
  createMangleNumberingContext() const override {
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33.0k
    return std::make_unique<ItaniumNumberingContext>(
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33.0k
        cast<ItaniumMangleContext>(Mangler.get()));
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33.0k
  }
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};
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}
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47.9k
CXXABI *clang::CreateItaniumCXXABI(ASTContext &Ctx) {
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47.9k
  return new ItaniumCXXABI(Ctx);
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}