ABIInfo.cpp

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//===- ABIInfo.cpp --------------------------------------------------------===//
//
// 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 "ABIInfo.h"
#include "ABIInfoImpl.h"
 
using namespace clang;
using namespace clang::CodeGen;
 
// Pin the vtable to this file.
ABIInfo::~ABIInfo() = default;
 
CGCXXABI &ABIInfo::getCXXABI() const { return CGT.getCXXABI(); }
 
ASTContext &ABIInfo::getContext() const { return CGT.getContext(); }
 
llvm::LLVMContext &ABIInfo::getVMContext() const {
  return CGT.getLLVMContext();
}
 
const llvm::DataLayout &ABIInfo::getDataLayout() const {
  return CGT.getDataLayout();
}
 
const TargetInfo &ABIInfo::getTarget() const { return CGT.getTarget(); }
 
const CodeGenOptions &ABIInfo::getCodeGenOpts() const {
  return CGT.getCodeGenOpts();
}
 
bool ABIInfo::isAndroid() const { return getTarget().getTriple().isAndroid(); }
 
bool ABIInfo::isOHOSFamily() const {
  return getTarget().getTriple().isOHOSFamily();
}
 
RValue ABIInfo::EmitMSVAArg(CodeGenFunction &CGF, Address VAListAddr,
                            QualType Ty, AggValueSlot Slot) const {
  return RValue::getIgnored();
}
 
bool ABIInfo::isHomogeneousAggregateBaseType(QualType Ty) const {
  return false;
}
 
bool ABIInfo::isHomogeneousAggregateSmallEnough(const Type *Base,
                                                uint64_t Members) const {
  return false;
}
 
bool ABIInfo::isZeroLengthBitfieldPermittedInHomogeneousAggregate() const {
  // For compatibility with GCC, ignore empty bitfields in C++ mode.
  return getContext().getLangOpts().CPlusPlus;
}
 
bool ABIInfo::isHomogeneousAggregate(QualType Ty, const Type *&Base,
                                     uint64_t &Members) const {
  if (const ConstantArrayType *AT = getContext().getAsConstantArrayType(Ty)) {
    uint64_t NElements = AT->getZExtSize();
    if (NElements == 0)
      return false;
    if (!isHomogeneousAggregate(AT->getElementType(), Base, Members))
      return false;
    Members *= NElements;
  } else if (const RecordType *RT = Ty->getAs<RecordType>()) {
    const RecordDecl *RD = RT->getDecl();
    if (RD->hasFlexibleArrayMember())
      return false;
 
    Members = 0;
 
    // If this is a C++ record, check the properties of the record such as
    // bases and ABI specific restrictions
    if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
      if (!getCXXABI().isPermittedToBeHomogeneousAggregate(CXXRD))
        return false;
 
      for (const auto &I : CXXRD->bases()) {
        // Ignore empty records.
        if (isEmptyRecord(getContext(), I.getType(), true))
          continue;
 
        uint64_t FldMembers;
        if (!isHomogeneousAggregate(I.getType(), Base, FldMembers))
          return false;
 
        Members += FldMembers;
      }
    }
 
    for (const auto *FD : RD->fields()) {
      // Ignore (non-zero arrays of) empty records.
      QualType FT = FD->getType();
      while (const ConstantArrayType *AT =
             getContext().getAsConstantArrayType(FT)) {
        if (AT->isZeroSize())
          return false;
        FT = AT->getElementType();
      }
      if (isEmptyRecord(getContext(), FT, true))
        continue;
 
      if (isZeroLengthBitfieldPermittedInHomogeneousAggregate() &&
          FD->isZeroLengthBitField())
        continue;
 
      uint64_t FldMembers;
      if (!isHomogeneousAggregate(FD->getType(), Base, FldMembers))
        return false;
 
      Members = (RD->isUnion() ?
                 std::max(Members, FldMembers) : Members + FldMembers);
    }
 
    if (!Base)
      return false;
 
    // Ensure there is no padding.
    if (getContext().getTypeSize(Base) * Members !=
        getContext().getTypeSize(Ty))
      return false;
  } else {
    Members = 1;
    if (const ComplexType *CT = Ty->getAs<ComplexType>()) {
      Members = 2;
      Ty = CT->getElementType();
    }
 
    // Most ABIs only support float, double, and some vector type widths.
    if (!isHomogeneousAggregateBaseType(Ty))
      return false;
 
    // The base type must be the same for all members.  Types that
    // agree in both total size and mode (float vs. vector) are
    // treated as being equivalent here.
    const Type *TyPtr = Ty.getTypePtr();
    if (!Base) {
      Base = TyPtr;
      // If it's a non-power-of-2 vector, its size is already a power-of-2,
      // so make sure to widen it explicitly.
      if (const VectorType *VT = Base->getAs<VectorType>()) {
        QualType EltTy = VT->getElementType();
        unsigned NumElements =
            getContext().getTypeSize(VT) / getContext().getTypeSize(EltTy);
        Base = getContext()
                   .getVectorType(EltTy, NumElements, VT->getVectorKind())
                   .getTypePtr();
      }
    }
 
    if (Base->isVectorType() != TyPtr->isVectorType() ||
        getContext().getTypeSize(Base) != getContext().getTypeSize(TyPtr))
      return false;
  }
  return Members > 0 && isHomogeneousAggregateSmallEnough(Base, Members);
}
 
bool ABIInfo::isPromotableIntegerTypeForABI(QualType Ty) const {
  if (getContext().isPromotableIntegerType(Ty))
    return true;
 
  if (const auto *EIT = Ty->