r246985 - Compute and preserve alignment more faithfully in IR-generation.

David Majnemer via cfe-commits cfe-commits at lists.llvm.org
Thu Sep 10 15:13:14 PDT 2015


The failure can be reproduced using ./libjpeg-turbo/build/.libs/lt-djpeg
-dct fast -outfile testout_420_q100_ifast.ppm
testout_420_q100_ifast_prog.jpg, it will die
in jsimd_ycc_rgb_convert_sse2.rowloop

I am using https://github.com/libjpeg-turbo/libjpeg-turbo.git at
revision 0d293537728f211888b04bed6ee19f71e0bda504

Let me know if this isn't enough to reproduce.

On Thu, Sep 10, 2015 at 2:39 PM, Chandler Carruth via cfe-commits <
cfe-commits at lists.llvm.org> wrote:

> In case anyone else is chasing the same thing, I wanted to post that we're
> seeing crashes in code introduced by this commit. Specifically, crashes
> inside of libjpeg-turbo's assembly implementation code, so its proving very
> challenging to track down. It looks like either incorrect vaargs stack
> setup, reaching past the redzone due to alignment padding, or something
> else weird.
>
> Notably, it is *not* a SIGILL due to an overaligned access to memory.
>
> Anyways, if we get a test case I'll probably file it and revert, but its
> proving *very* hard to track down so wanted to see if others have seen
> something here.
>
> -Chandler
>
>
> On Tue, Sep 8, 2015 at 1:07 AM John McCall via cfe-commits <
> cfe-commits at lists.llvm.org> wrote:
>
>> Modified: cfe/trunk/lib/CodeGen/TargetInfo.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/TargetInfo.cpp?rev=246985&r1=246984&r2=246985&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/CodeGen/TargetInfo.cpp (original)
>> +++ cfe/trunk/lib/CodeGen/TargetInfo.cpp Tue Sep  8 03:05:57 2015
>> @@ -39,7 +39,7 @@ static void AssignToArrayRange(CodeGen::
>>    for (unsigned I = FirstIndex; I <= LastIndex; ++I) {
>>      llvm::Value *Cell =
>>          Builder.CreateConstInBoundsGEP1_32(Builder.getInt8Ty(), Array,
>> I);
>> -    Builder.CreateStore(Value, Cell);
>> +    Builder.CreateAlignedStore(Value, Cell, CharUnits::One());
>>    }
>>  }
>>
>> @@ -48,6 +48,19 @@ static bool isAggregateTypeForABI(QualTy
>>           T->isMemberFunctionPointerType();
>>  }
>>
>> +ABIArgInfo
>> +ABIInfo::getNaturalAlignIndirect(QualType Ty, bool ByRef, bool Realign,
>> +                                 llvm::Type *Padding) const {
>> +  return ABIArgInfo::getIndirect(getContext().getTypeAlignInChars(Ty),
>> +                                 ByRef, Realign, Padding);
>> +}
>> +
>> +ABIArgInfo
>> +ABIInfo::getNaturalAlignIndirectInReg(QualType Ty, bool Realign) const {
>> +  return
>> ABIArgInfo::getIndirectInReg(getContext().getTypeAlignInChars(Ty),
>> +                                      /*ByRef*/ false, Realign);
>> +}
>> +
>>  ABIInfo::~ABIInfo() {}
>>
>>  static CGCXXABI::RecordArgABI getRecordArgABI(const RecordType *RT,
>> @@ -133,7 +146,7 @@ void ABIArgInfo::dump() const {
>>      OS << "InAlloca Offset=" << getInAllocaFieldIndex();
>>      break;
>>    case Indirect:
>> -    OS << "Indirect Align=" << getIndirectAlign()
>> +    OS << "Indirect Align=" << getIndirectAlign().getQuantity()
>>         << " ByVal=" << getIndirectByVal()
>>         << " Realign=" << getIndirectRealign();
>>      break;
>> @@ -144,6 +157,125 @@ void ABIArgInfo::dump() const {
>>    OS << ")\n";
>>  }
>>
>> +/// Emit va_arg for a platform using the common void* representation,
>> +/// where arguments are simply emitted in an array of slots on the stack.
>> +///
>> +/// This version implements the core direct-value passing rules.
>> +///
>> +/// \param SlotSize - The size and alignment of a stack slot.
>> +///   Each argument will be allocated to a multiple of this number of
>> +///   slots, and all the slots will be aligned to this value.
>> +/// \param AllowHigherAlign - The slot alignment is not a cap;
>> +///   an argument type with an alignment greater than the slot size
>> +///   will be emitted on a higher-alignment address, potentially
>> +///   leaving one or more empty slots behind as padding.  If this
>> +///   is false, the returned address might be less-aligned than
>> +///   DirectAlign.
>> +static Address emitVoidPtrDirectVAArg(CodeGenFunction &CGF,
>> +                                      Address VAListAddr,
>> +                                      llvm::Type *DirectTy,
>> +                                      CharUnits DirectSize,
>> +                                      CharUnits DirectAlign,
>> +                                      CharUnits SlotSize,
>> +                                      bool AllowHigherAlign) {
>> +  // Cast the element type to i8* if necessary.  Some platforms define
>> +  // va_list as a struct containing an i8* instead of just an i8*.
>> +  if (VAListAddr.getElementType() != CGF.Int8PtrTy)
>> +    VAListAddr = CGF.Builder.CreateElementBitCast(VAListAddr,
>> CGF.Int8PtrTy);
>> +
>> +  llvm::Value *Ptr = CGF.Builder.CreateLoad(VAListAddr, "argp.cur");
>> +
>> +  // If the CC aligns values higher than the slot size, do so if needed.
>> +  Address Addr = Address::invalid();
>> +  if (AllowHigherAlign && DirectAlign > SlotSize) {
>> +    llvm::Value *PtrAsInt = Ptr;
>> +    PtrAsInt = CGF.Builder.CreatePtrToInt(PtrAsInt, CGF.IntPtrTy);
>> +    PtrAsInt = CGF.Builder.CreateAdd(PtrAsInt,
>> +          llvm::ConstantInt::get(CGF.IntPtrTy, DirectAlign.getQuantity()
>> - 1));
>> +    PtrAsInt = CGF.Builder.CreateAnd(PtrAsInt,
>> +             llvm::ConstantInt::get(CGF.IntPtrTy,
>> -DirectAlign.getQuantity()));
>> +    Addr = Address(CGF.Builder.CreateIntToPtr(PtrAsInt, Ptr->getType(),
>> +                                              "argp.cur.aligned"),
>> +                   DirectAlign);
>> +  } else {
>> +    Addr = Address(Ptr, SlotSize);
>> +  }
>> +
>> +  // Advance the pointer past the argument, then store that back.
>> +  CharUnits FullDirectSize = DirectSize.RoundUpToAlignment(SlotSize);
>> +  llvm::Value *NextPtr =
>> +    CGF.Builder.CreateConstInBoundsByteGEP(Addr.getPointer(),
>> FullDirectSize,
>> +                                           "argp.next");
>> +  CGF.Builder.CreateStore(NextPtr, VAListAddr);
>> +
>> +  // If the argument is smaller than a slot, and this is a big-endian
>> +  // target, the argument will be right-adjusted in its slot.
>> +  if (DirectSize < SlotSize && CGF.CGM.getDataLayout().isBigEndian()) {
>> +    Addr = CGF.Builder.CreateConstInBoundsByteGEP(Addr, SlotSize -
>> DirectSize);
>> +  }
>> +
>> +  Addr = CGF.Builder.CreateElementBitCast(Addr, DirectTy);
>> +  return Addr;
>> +}
>> +
>> +/// Emit va_arg for a platform using the common void* representation,
>> +/// where arguments are simply emitted in an array of slots on the stack.
>> +///
>> +/// \param IsIndirect - Values of this type are passed indirectly.
>> +/// \param ValueInfo - The size and alignment of this type, generally
>> +///   computed with getContext().getTypeInfoInChars(ValueTy).
>> +/// \param SlotSizeAndAlign - The size and alignment of a stack slot.
>> +///   Each argument will be allocated to a multiple of this number of
>> +///   slots, and all the slots will be aligned to this value.
>> +/// \param AllowHigherAlign - The slot alignment is not a cap;
>> +///   an argument type with an alignment greater than the slot size
>> +///   will be emitted on a higher-alignment address, potentially
>> +///   leaving one or more empty slots behind as padding.
>> +static Address emitVoidPtrVAArg(CodeGenFunction &CGF, Address VAListAddr,
>> +                                QualType ValueTy, bool IsIndirect,
>> +                                std::pair<CharUnits, CharUnits>
>> ValueInfo,
>> +                                CharUnits SlotSizeAndAlign,
>> +                                bool AllowHigherAlign) {
>> +  // The size and alignment of the value that was passed directly.
>> +  CharUnits DirectSize, DirectAlign;
>> +  if (IsIndirect) {
>> +    DirectSize = CGF.getPointerSize();
>> +    DirectAlign = CGF.getPointerAlign();
>> +  } else {
>> +    DirectSize = ValueInfo.first;
>> +    DirectAlign = ValueInfo.second;
>> +  }
>> +
>> +  // Cast the address we've calculated to the right type.
>> +  llvm::Type *DirectTy = CGF.ConvertTypeForMem(ValueTy);
>> +  if (IsIndirect)
>> +    DirectTy = DirectTy->getPointerTo(0);
>> +
>> +  Address Addr = emitVoidPtrDirectVAArg(CGF, VAListAddr, DirectTy,
>> +                                        DirectSize, DirectAlign,
>> +                                        SlotSizeAndAlign,
>> +                                        AllowHigherAlign);
>> +
>> +  if (IsIndirect) {
>> +    Addr = Address(CGF.Builder.CreateLoad(Addr), ValueInfo.second);
>> +  }
>> +
>> +  return Addr;
>> +
>> +}
>> +
>> +static Address emitMergePHI(CodeGenFunction &CGF,
>> +                            Address Addr1, llvm::BasicBlock *Block1,
>> +                            Address Addr2, llvm::BasicBlock *Block2,
>> +                            const llvm::Twine &Name = "") {
>> +  assert(Addr1.getType() == Addr2.getType());
>> +  llvm::PHINode *PHI = CGF.Builder.CreatePHI(Addr1.getType(), 2, Name);
>> +  PHI->addIncoming(Addr1.getPointer(), Block1);
>> +  PHI->addIncoming(Addr2.getPointer(), Block2);
>> +  CharUnits Align = std::min(Addr1.getAlignment(), Addr2.getAlignment());
>> +  return Address(PHI, Align);
>> +}
>> +
>>  TargetCodeGenInfo::~TargetCodeGenInfo() { delete Info; }
>>
>>  // If someone can figure out a general rule for this, that would be
>> great.
>> @@ -394,8 +526,8 @@ public:
>>        I.info = classifyArgumentType(I.type);
>>    }
>>
>> -  llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                         CodeGenFunction &CGF) const override;
>> +  Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
>> +                    QualType Ty) const override;
>>  };
>>
>>  class DefaultTargetCodeGenInfo : public TargetCodeGenInfo {
>> @@ -404,9 +536,9 @@ public:
>>      : TargetCodeGenInfo(new DefaultABIInfo(CGT)) {}
>>  };
>>
>> -llvm::Value *DefaultABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType
>> Ty,
>> -                                       CodeGenFunction &CGF) const {
>> -  return nullptr;
>> +Address DefaultABIInfo::EmitVAArg(CodeGenFunction &CGF, Address
>> VAListAddr,
>> +                                  QualType Ty) const {
>> +  return Address::invalid();
>>  }
>>
>>  ABIArgInfo DefaultABIInfo::classifyArgumentType(QualType Ty) const {
>> @@ -416,9 +548,9 @@ ABIArgInfo DefaultABIInfo::classifyArgum
>>      // Records with non-trivial destructors/copy-constructors should not
>> be
>>      // passed by value.
>>      if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, getCXXABI()))
>> -      return ABIArgInfo::getIndirect(0, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>> +      return getNaturalAlignIndirect(Ty, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>>
>> -    return ABIArgInfo::getIndirect(0);
>> +    return getNaturalAlignIndirect(Ty);
>>    }
>>
>>    // Treat an enum type as its underlying type.
>> @@ -434,7 +566,7 @@ ABIArgInfo DefaultABIInfo::classifyRetur
>>      return ABIArgInfo::getIgnore();
>>
>>    if (isAggregateTypeForABI(RetTy))
>> -    return ABIArgInfo::getIndirect(0);
>> +    return getNaturalAlignIndirect(RetTy);
>>
>>    // Treat an enum type as its underlying type.
>>    if (const EnumType *EnumTy = RetTy->getAs<EnumType>())
>> @@ -482,10 +614,8 @@ ABIArgInfo WebAssemblyABIInfo::classifyA
>>    if (isAggregateTypeForABI(Ty)) {
>>      // Records with non-trivial destructors/copy-constructors should not
>> be
>>      // passed by value.
>> -    unsigned TypeAlign =
>> getContext().getTypeAlignInChars(Ty).getQuantity();
>>      if (auto RAA = getRecordArgABI(Ty, getCXXABI()))
>> -      return ABIArgInfo::getIndirect(TypeAlign,
>> -                                     RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>> +      return getNaturalAlignIndirect(Ty, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>>      // Ignore empty structs/unions.
>>      if (isEmptyRecord(getContext(), Ty, true))
>>        return ABIArgInfo::getIgnore();
>> @@ -494,7 +624,7 @@ ABIArgInfo WebAssemblyABIInfo::classifyA
>>      // though watch out for things like bitfields.
>>      if (const Type *SeltTy = isSingleElementStruct(Ty, getContext()))
>>        return ABIArgInfo::getDirect(CGT.ConvertType(QualType(SeltTy, 0)));
>> -    return ABIArgInfo::getIndirect(TypeAlign);
>> +    return getNaturalAlignIndirect(Ty);
>>    }
>>
>>    // Otherwise just do the default thing.
>> @@ -536,8 +666,8 @@ class PNaClABIInfo : public ABIInfo {
>>    ABIArgInfo classifyArgumentType(QualType RetTy) const;
>>
>>    void computeInfo(CGFunctionInfo &FI) const override;
>> -  llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                         CodeGenFunction &CGF) const override;
>> +  Address EmitVAArg(CodeGenFunction &CGF,
>> +                    Address VAListAddr, QualType Ty) const override;
>>  };
>>
>>  class PNaClTargetCodeGenInfo : public TargetCodeGenInfo {
>> @@ -554,17 +684,17 @@ void PNaClABIInfo::computeInfo(CGFunctio
>>      I.info = classifyArgumentType(I.type);
>>  }
>>
>> -llvm::Value *PNaClABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType
>> Ty,
>> -                                       CodeGenFunction &CGF) const {
>> -  return nullptr;
>> +Address PNaClABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
>> +                                QualType Ty) const {
>> +  return Address::invalid();
>>  }
>>
>>  /// \brief Classify argument of given type \p Ty.
>>  ABIArgInfo PNaClABIInfo::classifyArgumentType(QualType Ty) const {
>>    if (isAggregateTypeForABI(Ty)) {
>>      if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, getCXXABI()))
>> -      return ABIArgInfo::getIndirect(0, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>> -    return ABIArgInfo::getIndirect(0);
>> +      return getNaturalAlignIndirect(Ty, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>> +    return getNaturalAlignIndirect(Ty);
>>    } else if (const EnumType *EnumTy = Ty->getAs<EnumType>()) {
>>      // Treat an enum type as its underlying type.
>>      Ty = EnumTy->getDecl()->getIntegerType();
>> @@ -583,7 +713,7 @@ ABIArgInfo PNaClABIInfo::classifyReturnT
>>
>>    // In the PNaCl ABI we always return records/structures on the stack.
>>    if (isAggregateTypeForABI(RetTy))
>> -    return ABIArgInfo::getIndirect(0);
>> +    return getNaturalAlignIndirect(RetTy);
>>
>>    // Treat an enum type as its underlying type.
>>    if (const EnumType *EnumTy = RetTy->getAs<EnumType>())
>> @@ -687,7 +817,7 @@ class X86_32ABIInfo : public ABIInfo {
>>    /// such that the argument will be passed in memory.
>>    ABIArgInfo getIndirectResult(QualType Ty, bool ByVal, CCState &State)
>> const;
>>
>> -  ABIArgInfo getIndirectReturnResult(CCState &State) const;
>> +  ABIArgInfo getIndirectReturnResult(QualType Ty, CCState &State) const;
>>
>>    /// \brief Return the alignment to use for the given type on the stack.
>>    unsigned getTypeStackAlignInBytes(QualType Ty, unsigned Align) const;
>> @@ -702,14 +832,14 @@ class X86_32ABIInfo : public ABIInfo {
>>    void rewriteWithInAlloca(CGFunctionInfo &FI) const;
>>
>>    void addFieldToArgStruct(SmallVector<llvm::Type *, 6> &FrameFields,
>> -                           unsigned &StackOffset, ABIArgInfo &Info,
>> +                           CharUnits &StackOffset, ABIArgInfo &Info,
>>                             QualType Type) const;
>>
>>  public:
>>
>>    void computeInfo(CGFunctionInfo &FI) const override;
>> -  llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                         CodeGenFunction &CGF) const override;
>> +  Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
>> +                    QualType Ty) const override;
>>
>>    X86_32ABIInfo(CodeGen::CodeGenTypes &CGT, bool d, bool p, bool w,
>>                  unsigned r)
>> @@ -893,14 +1023,14 @@ bool X86_32ABIInfo::shouldReturnTypeInRe
>>    return true;
>>  }
>>
>> -ABIArgInfo X86_32ABIInfo::getIndirectReturnResult(CCState &State) const {
>> +ABIArgInfo X86_32ABIInfo::getIndirectReturnResult(QualType RetTy,
>> CCState &State) const {
>>    // If the return value is indirect, then the hidden argument is
>> consuming one
>>    // integer register.
>>    if (State.FreeRegs) {
>>      --State.FreeRegs;
>> -    return ABIArgInfo::getIndirectInReg(/*Align=*/0, /*ByVal=*/false);
>> +    return getNaturalAlignIndirectInReg(RetTy);
>>    }
>> -  return ABIArgInfo::getIndirect(/*Align=*/0, /*ByVal=*/false);
>> +  return getNaturalAlignIndirect(RetTy, /*ByVal=*/false);
>>  }
>>
>>  ABIArgInfo X86_32ABIInfo::classifyReturnType(QualType RetTy,
>> @@ -935,7 +1065,7 @@ ABIArgInfo X86_32ABIInfo::classifyReturn
>>          return
>> ABIArgInfo::getDirect(llvm::IntegerType::get(getVMContext(),
>>                                                              Size));
>>
>> -      return getIndirectReturnResult(State);
>> +      return getIndirectReturnResult(RetTy, State);
>>      }
>>
>>      return ABIArgInfo::getDirect();
>> @@ -945,12 +1075,12 @@ ABIArgInfo X86_32ABIInfo::classifyReturn
>>      if (const RecordType *RT = RetTy->getAs<RecordType>()) {
>>        // Structures with flexible arrays are always indirect.
>>        if (RT->getDecl()->hasFlexibleArrayMember())
>> -        return getIndirectReturnResult(State);
>> +        return getIndirectReturnResult(RetTy, State);
>>      }
>>
>>      // If specified, structs and unions are always indirect.
>>      if (!IsSmallStructInRegABI && !RetTy->isAnyComplexType())
>> -      return getIndirectReturnResult(State);
>> +      return getIndirectReturnResult(RetTy, State);
>>
>>      // Small structures which are register sized are generally returned
>>      // in a register.
>> @@ -972,7 +1102,7 @@ ABIArgInfo X86_32ABIInfo::classifyReturn
>>        return
>> ABIArgInfo::getDirect(llvm::IntegerType::get(getVMContext(),Size));
>>      }
>>
>> -    return getIndirectReturnResult(State);
>> +    return getIndirectReturnResult(RetTy, State);
>>    }
>>
>>    // Treat an enum type as its underlying type.
>> @@ -1038,21 +1168,22 @@ ABIArgInfo X86_32ABIInfo::getIndirectRes
>>    if (!ByVal) {
>>      if (State.FreeRegs) {
>>        --State.FreeRegs; // Non-byval indirects just use one pointer.
>> -      return ABIArgInfo::getIndirectInReg(0, false);
>> +      return getNaturalAlignIndirectInReg(Ty);
>>      }
>> -    return ABIArgInfo::getIndirect(0, false);
>> +    return getNaturalAlignIndirect(Ty, false);
>>    }
>>
>>    // Compute the byval alignment.
>>    unsigned TypeAlign = getContext().getTypeAlign(Ty) / 8;
>>    unsigned StackAlign = getTypeStackAlignInBytes(Ty, TypeAlign);
>>    if (StackAlign == 0)
>> -    return ABIArgInfo::getIndirect(4, /*ByVal=*/true);
>> +    return ABIArgInfo::getIndirect(CharUnits::fromQuantity(4),
>> /*ByVal=*/true);
>>
>>    // If the stack alignment is less than the type alignment, realign the
>>    // argument.
>>    bool Realign = TypeAlign > StackAlign;
>> -  return ABIArgInfo::getIndirect(StackAlign, /*ByVal=*/true, Realign);
>> +  return ABIArgInfo::getIndirect(CharUnits::fromQuantity(StackAlign),
>> +                                 /*ByVal=*/true, Realign);
>>  }
>>
>>  X86_32ABIInfo::Class X86_32ABIInfo::classify(QualType Ty) const {
>> @@ -1259,22 +1390,23 @@ void X86_32ABIInfo::computeInfo(CGFuncti
>>
>>  void
>>  X86_32ABIInfo::addFieldToArgStruct(SmallVector<llvm::Type *, 6>
>> &FrameFields,
>> -                                   unsigned &StackOffset,
>> -                                   ABIArgInfo &Info, QualType Type)
>> const {
>> -  assert(StackOffset % 4U == 0 && "unaligned inalloca struct");
>> +                                   CharUnits &StackOffset, ABIArgInfo
>> &Info,
>> +                                   QualType Type) const {
>> +  // Arguments are always 4-byte-aligned.
>> +  CharUnits FieldAlign = CharUnits::fromQuantity(4);
>> +
>> +  assert(StackOffset.isMultipleOf(FieldAlign) && "unaligned inalloca
>> struct");
>>    Info = ABIArgInfo::getInAlloca(FrameFields.size());
>>    FrameFields.push_back(CGT.ConvertTypeForMem(Type));
>> -  StackOffset += getContext().getTypeSizeInChars(Type).getQuantity();
>> +  StackOffset += getContext().getTypeSizeInChars(Type);
>>
>> -  // Insert padding bytes to respect alignment.  For x86_32, each
>> argument is 4
>> -  // byte aligned.
>> -  if (StackOffset % 4U) {
>> -    unsigned OldOffset = StackOffset;
>> -    StackOffset = llvm::RoundUpToAlignment(StackOffset, 4U);
>> -    unsigned NumBytes = StackOffset - OldOffset;
>> -    assert(NumBytes);
>> +  // Insert padding bytes to respect alignment.
>> +  CharUnits FieldEnd = StackOffset;
>> +  StackOffset = FieldEnd.RoundUpToAlignment(FieldAlign);
>> +  if (StackOffset != FieldEnd) {
>> +    CharUnits NumBytes = StackOffset - FieldEnd;
>>      llvm::Type *Ty = llvm::Type::getInt8Ty(getVMContext());
>> -    Ty = llvm::ArrayType::get(Ty, NumBytes);
>> +    Ty = llvm::ArrayType::get(Ty, NumBytes.getQuantity());
>>      FrameFields.push_back(Ty);
>>    }
>>  }
>> @@ -1305,7 +1437,10 @@ void X86_32ABIInfo::rewriteWithInAlloca(
>>    // Build a packed struct type for all of the arguments in memory.
>>    SmallVector<llvm::Type *, 6> FrameFields;
>>
>> -  unsigned StackOffset = 0;
>> +  // The stack alignment is always 4.
>> +  CharUnits StackAlign = CharUnits::fromQuantity(4);
>> +
>> +  CharUnits StackOffset;
>>    CGFunctionInfo::arg_iterator I = FI.arg_begin(), E = FI.arg_end();
>>
>>    // Put 'this' into the struct before 'sret', if necessary.
>> @@ -1337,47 +1472,25 @@ void X86_32ABIInfo::rewriteWithInAlloca(
>>    }
>>
>>    FI.setArgStruct(llvm::StructType::get(getVMContext(), FrameFields,
>> -                                        /*isPacked=*/true));
>> +                                        /*isPacked=*/true),
>> +                  StackAlign);
>>  }
>>
>> -llvm::Value *X86_32ABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType
>> Ty,
>> -                                      CodeGenFunction &CGF) const {
>> -  llvm::Type *BPP = CGF.Int8PtrPtrTy;
>> +Address X86_32ABIInfo::EmitVAArg(CodeGenFunction &CGF,
>> +                                 Address VAListAddr, QualType Ty) const {
>>
>> -  CGBuilderTy &Builder = CGF.Builder;
>> -  llvm::Value *VAListAddrAsBPP = Builder.CreateBitCast(VAListAddr, BPP,
>> -                                                       "ap");
>> -  llvm::Value *Addr = Builder.CreateLoad(VAListAddrAsBPP, "ap.cur");
>> -
>> -  // Compute if the address needs to be aligned
>> -  unsigned Align =
>> CGF.getContext().getTypeAlignInChars(Ty).getQuantity();
>> -  Align = getTypeStackAlignInBytes(Ty, Align);
>> -  Align = std::max(Align, 4U);
>> -  if (Align > 4) {
>> -    // addr = (addr + align - 1) & -align;
>> -    llvm::Value *Offset =
>> -      llvm::ConstantInt::get(CGF.Int32Ty, Align - 1);
>> -    Addr = CGF.Builder.CreateGEP(Addr, Offset);
>> -    llvm::Value *AsInt = CGF.Builder.CreatePtrToInt(Addr,
>> -                                                    CGF.Int32Ty);
>> -    llvm::Value *Mask = llvm::ConstantInt::get(CGF.Int32Ty, -Align);
>> -    Addr = CGF.Builder.CreateIntToPtr(CGF.Builder.CreateAnd(AsInt, Mask),
>> -                                      Addr->getType(),
>> -                                      "ap.cur.aligned");
>> -  }
>> -
>> -  llvm::Type *PTy =
>> -    llvm::PointerType::getUnqual(CGF.ConvertType(Ty));
>> -  llvm::Value *AddrTyped = Builder.CreateBitCast(Addr, PTy);
>> -
>> -  uint64_t Offset =
>> -    llvm::RoundUpToAlignment(CGF.getContext().getTypeSize(Ty) / 8,
>> Align);
>> -  llvm::Value *NextAddr =
>> -    Builder.CreateGEP(Addr, llvm::ConstantInt::get(CGF.Int32Ty, Offset),
>> -                      "ap.next");
>> -  Builder.CreateStore(NextAddr, VAListAddrAsBPP);
>> +  auto TypeInfo = getContext().getTypeInfoInChars(Ty);
>>
>> -  return AddrTyped;
>> +  // x86-32 changes the alignment of certain arguments on the stack.
>> +  //
>> +  // Just messing with TypeInfo like this works because we never pass
>> +  // anything indirectly.
>> +  TypeInfo.second = CharUnits::fromQuantity(
>> +                getTypeStackAlignInBytes(Ty,
>> TypeInfo.second.getQuantity()));
>> +
>> +  return emitVoidPtrVAArg(CGF, VAListAddr, Ty, /*Indirect*/ false,
>> +                          TypeInfo, CharUnits::fromQuantity(4),
>> +                          /*AllowHigherAlign*/ true);
>>  }
>>
>>  bool X86_32TargetCodeGenInfo::isStructReturnInRegABI(
>> @@ -1449,8 +1562,9 @@ bool X86_32TargetCodeGenInfo::initDwarfE
>>    } else {
>>      // 9 is %eflags, which doesn't get a size on Darwin for some
>>      // reason.
>> -    Builder.CreateStore(
>> -        Four8, Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, Address,
>> 9));
>> +    Builder.CreateAlignedStore(
>> +        Four8, Builder.CreateConstInBoundsGEP1_32(CGF.Int8Ty, Address,
>> 9),
>> +                               CharUnits::One());
>>
>>      // 11-16 are st(0..5).  Not sure why we stop at 5.
>>      // These have size 12, which is sizeof(long double) on
>> @@ -1619,8 +1733,8 @@ public:
>>
>>    void computeInfo(CGFunctionInfo &FI) const override;
>>
>> -  llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                         CodeGenFunction &CGF) const override;
>> +  Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
>> +                    QualType Ty) const override;
>>
>>    bool has64BitPointers() const {
>>      return Has64BitPointers;
>> @@ -1638,8 +1752,8 @@ public:
>>
>>    void computeInfo(CGFunctionInfo &FI) const override;
>>
>> -  llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                         CodeGenFunction &CGF) const override;
>> +  Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
>> +                    QualType Ty) const override;
>>
>>    bool isHomogeneousAggregateBaseType(QualType Ty) const override {
>>      // FIXME: Assumes vectorcall is in use.
>> @@ -2257,7 +2371,7 @@ ABIArgInfo X86_64ABIInfo::getIndirectRet
>>              ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
>>    }
>>
>> -  return ABIArgInfo::getIndirect(0);
>> +  return getNaturalAlignIndirect(Ty);
>>  }
>>
>>  bool X86_64ABIInfo::IsIllegalVectorType(QualType Ty) const {
>> @@ -2291,7 +2405,7 @@ ABIArgInfo X86_64ABIInfo::getIndirectRes
>>    }
>>
>>    if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, getCXXABI()))
>> -    return ABIArgInfo::getIndirect(0, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>> +    return getNaturalAlignIndirect(Ty, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>>
>>    // Compute the byval alignment. We specify the alignment of the byval
>> in all
>>    // cases so that the mid-level optimizer knows the alignment of the
>> byval.
>> @@ -2328,7 +2442,7 @@ ABIArgInfo X86_64ABIInfo::getIndirectRes
>>                                                            Size));
>>    }
>>
>> -  return ABIArgInfo::getIndirect(Align);
>> +  return ABIArgInfo::getIndirect(CharUnits::fromQuantity(Align));
>>  }
>>
>>  /// The ABI specifies that a value should be passed in a full vector
>> XMM/YMM
>> @@ -2912,11 +3026,10 @@ void X86_64ABIInfo::computeInfo(CGFuncti
>>    }
>>  }
>>
>> -static llvm::Value *EmitVAArgFromMemory(llvm::Value *VAListAddr,
>> -                                        QualType Ty,
>> -                                        CodeGenFunction &CGF) {
>> -  llvm::Value *overflow_arg_area_p = CGF.Builder.CreateStructGEP(
>> -      nullptr, VAListAddr, 2, "overflow_arg_area_p");
>> +static Address EmitX86_64VAArgFromMemory(CodeGenFunction &CGF,
>> +                                         Address VAListAddr, QualType
>> Ty) {
>> +  Address overflow_arg_area_p = CGF.Builder.CreateStructGEP(
>> +      VAListAddr, 2, CharUnits::fromQuantity(8), "overflow_arg_area_p");
>>    llvm::Value *overflow_arg_area =
>>      CGF.Builder.CreateLoad(overflow_arg_area_p, "overflow_arg_area");
>>
>> @@ -2924,7 +3037,7 @@ static llvm::Value *EmitVAArgFromMemory(
>>    // byte boundary if alignment needed by type exceeds 8 byte boundary.
>>    // It isn't stated explicitly in the standard, but in practice we use
>>    // alignment greater than 16 where necessary.
>> -  uint64_t Align = CGF.getContext().getTypeAlign(Ty) / 8;
>> +  uint64_t Align =
>> CGF.getContext().getTypeAlignInChars(Ty).getQuantity();
>>    if (Align > 8) {
>>      // overflow_arg_area = (overflow_arg_area + align - 1) & -align;
>>      llvm::Value *Offset =
>> @@ -2958,11 +3071,11 @@ static llvm::Value *EmitVAArgFromMemory(
>>    CGF.Builder.CreateStore(overflow_arg_area, overflow_arg_area_p);
>>
>>    // AMD64-ABI 3.5.7p5: Step 11. Return the fetched type.
>> -  return Res;
>> +  return Address(Res, CharUnits::fromQuantity(Align));
>>  }
>>
>> -llvm::Value *X86_64ABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType
>> Ty,
>> -                                      CodeGenFunction &CGF) const {
>> +Address X86_64ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address
>> VAListAddr,
>> +                                 QualType Ty) const {
>>    // Assume that va_list type is correct; should be pointer to LLVM type:
>>    // struct {
>>    //   i32 gp_offset;
>> @@ -2972,14 +3085,14 @@ llvm::Value *X86_64ABIInfo::EmitVAArg(ll
>>    // };
>>    unsigned neededInt, neededSSE;
>>
>> -  Ty = CGF.getContext().getCanonicalType(Ty);
>> +  Ty = getContext().getCanonicalType(Ty);
>>    ABIArgInfo AI = classifyArgumentType(Ty, 0, neededInt, neededSSE,
>>                                         /*isNamedArg*/false);
>>
>>    // AMD64-ABI 3.5.7p5: Step 1. Determine whether type may be passed
>>    // in the registers. If not go to step 7.
>>    if (!neededInt && !neededSSE)
>> -    return EmitVAArgFromMemory(VAListAddr, Ty, CGF);
>> +    return EmitX86_64VAArgFromMemory(CGF, VAListAddr, Ty);
>>
>>    // AMD64-ABI 3.5.7p5: Step 2. Compute num_gp to hold the number of
>>    // general purpose registers needed to pass type and num_fp to hold
>> @@ -2993,11 +3106,12 @@ llvm::Value *X86_64ABIInfo::EmitVAArg(ll
>>    // register save space).
>>
>>    llvm::Value *InRegs = nullptr;
>> -  llvm::Value *gp_offset_p = nullptr, *gp_offset = nullptr;
>> -  llvm::Value *fp_offset_p = nullptr, *fp_offset = nullptr;
>> +  Address gp_offset_p = Address::invalid(), fp_offset_p =
>> Address::invalid();
>> +  llvm::Value *gp_offset = nullptr, *fp_offset = nullptr;
>>    if (neededInt) {
>>      gp_offset_p =
>> -        CGF.Builder.CreateStructGEP(nullptr, VAListAddr, 0,
>> "gp_offset_p");
>> +        CGF.Builder.CreateStructGEP(VAListAddr, 0, CharUnits::Zero(),
>> +                                    "gp_offset_p");
>>      gp_offset = CGF.Builder.CreateLoad(gp_offset_p, "gp_offset");
>>      InRegs = llvm::ConstantInt::get(CGF.Int32Ty, 48 - neededInt * 8);
>>      InRegs = CGF.Builder.CreateICmpULE(gp_offset, InRegs, "fits_in_gp");
>> @@ -3005,7 +3119,8 @@ llvm::Value *X86_64ABIInfo::EmitVAArg(ll
>>
>>    if (neededSSE) {
>>      fp_offset_p =
>> -        CGF.Builder.CreateStructGEP(nullptr, VAListAddr, 1,
>> "fp_offset_p");
>> +        CGF.Builder.CreateStructGEP(VAListAddr, 1,
>> CharUnits::fromQuantity(4),
>> +                                    "fp_offset_p");
>>      fp_offset = CGF.Builder.CreateLoad(fp_offset_p, "fp_offset");
>>      llvm::Value *FitsInFP =
>>        llvm::ConstantInt::get(CGF.Int32Ty, 176 - neededSSE * 16);
>> @@ -3033,14 +3148,17 @@ llvm::Value *X86_64ABIInfo::EmitVAArg(ll
>>    // simple assembling of a structure from scattered addresses has many
>> more
>>    // loads than necessary. Can we clean this up?
>>    llvm::Type *LTy = CGF.ConvertTypeForMem(Ty);
>> -  llvm::Value *RegAddr = CGF.Builder.CreateLoad(
>> -      CGF.Builder.CreateStructGEP(nullptr, VAListAddr, 3),
>> "reg_save_area");
>> +  llvm::Value *RegSaveArea = CGF.Builder.CreateLoad(
>> +      CGF.Builder.CreateStructGEP(VAListAddr, 3,
>> CharUnits::fromQuantity(16)),
>> +                                  "reg_save_area");
>> +
>> +  Address RegAddr = Address::invalid();
>>    if (neededInt && neededSSE) {
>>      // FIXME: Cleanup.
>>      assert(AI.isDirect() && "Unexpected ABI info for mixed regs");
>>      llvm::StructType *ST = cast<llvm::StructType>(AI.getCoerceToType());
>> -    llvm::Value *Tmp = CGF.CreateMemTemp(Ty);
>> -    Tmp = CGF.Builder.CreateBitCast(Tmp, ST->getPointerTo());
>> +    Address Tmp = CGF.CreateMemTemp(Ty);
>> +    Tmp = CGF.Builder.CreateElementBitCast(Tmp, ST);
>>      assert(ST->getNumElements() == 2 && "Unexpected ABI info for mixed
>> regs");
>>      llvm::Type *TyLo = ST->getElementType(0);
>>      llvm::Type *TyHi = ST->getElementType(1);
>> @@ -3048,57 +3166,77 @@ llvm::Value *X86_64ABIInfo::EmitVAArg(ll
>>             "Unexpected ABI info for mixed regs");
>>      llvm::Type *PTyLo = llvm::PointerType::getUnqual(TyLo);
>>      llvm::Type *PTyHi = llvm::PointerType::getUnqual(TyHi);
>> -    llvm::Value *GPAddr = CGF.Builder.CreateGEP(RegAddr, gp_offset);
>> -    llvm::Value *FPAddr = CGF.Builder.CreateGEP(RegAddr, fp_offset);
>> +    llvm::Value *GPAddr = CGF.Builder.CreateGEP(RegSaveArea, gp_offset);
>> +    llvm::Value *FPAddr = CGF.Builder.CreateGEP(RegSaveArea, fp_offset);
>>      llvm::Value *RegLoAddr = TyLo->isFPOrFPVectorTy() ? FPAddr : GPAddr;
>>      llvm::Value *RegHiAddr = TyLo->isFPOrFPVectorTy() ? GPAddr : FPAddr;
>> +
>> +    // Copy the first element.
>>      llvm::Value *V =
>> -      CGF.Builder.CreateLoad(CGF.Builder.CreateBitCast(RegLoAddr,
>> PTyLo));
>> -    CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(ST, Tmp, 0));
>> -    V = CGF.Builder.CreateLoad(CGF.Builder.CreateBitCast(RegHiAddr,
>> PTyHi));
>> -    CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(ST, Tmp, 1));
>> +      CGF.Builder.CreateDefaultAlignedLoad(
>> +                               CGF.Builder.CreateBitCast(RegLoAddr,
>> PTyLo));
>> +    CGF.Builder.CreateStore(V,
>> +                    CGF.Builder.CreateStructGEP(Tmp, 0,
>> CharUnits::Zero()));
>> +
>> +    // Copy the second element.
>> +    V = CGF.Builder.CreateDefaultAlignedLoad(
>> +                               CGF.Builder.CreateBitCast(RegHiAddr,
>> PTyHi));
>> +    CharUnits Offset = CharUnits::fromQuantity(
>> +
>>  getDataLayout().getStructLayout(ST)->getElementOffset(1));
>> +    CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(Tmp, 1,
>> Offset));
>>
>> -    RegAddr = CGF.Builder.CreateBitCast(Tmp,
>> -
>> llvm::PointerType::getUnqual(LTy));
>> +    RegAddr = CGF.Builder.CreateElementBitCast(Tmp, LTy);
>>    } else if (neededInt) {
>> -    RegAddr = CGF.Builder.CreateGEP(RegAddr, gp_offset);
>> -    RegAddr = CGF.Builder.CreateBitCast(RegAddr,
>> -
>> llvm::PointerType::getUnqual(LTy));
>> +    RegAddr = Address(CGF.Builder.CreateGEP(RegSaveArea, gp_offset),
>> +                      CharUnits::fromQuantity(8));
>> +    RegAddr = CGF.Builder.CreateElementBitCast(RegAddr, LTy);
>>
>>      // Copy to a temporary if necessary to ensure the appropriate
>> alignment.
>>      std::pair<CharUnits, CharUnits> SizeAlign =
>> -        CGF.getContext().getTypeInfoInChars(Ty);
>> +        getContext().getTypeInfoInChars(Ty);
>>      uint64_t TySize = SizeAlign.first.getQuantity();
>> -    unsigned TyAlign = SizeAlign.second.getQuantity();
>> -    if (TyAlign > 8) {
>> -      llvm::Value *Tmp = CGF.CreateMemTemp(Ty);
>> -      CGF.Builder.CreateMemCpy(Tmp, RegAddr, TySize, 8, false);
>> +    CharUnits TyAlign = SizeAlign.second;
>> +
>> +    // Copy into a temporary if the type is more aligned than the
>> +    // register save area.
>> +    if (TyAlign.getQuantity() > 8) {
>> +      Address Tmp = CGF.CreateMemTemp(Ty);
>> +      CGF.Builder.CreateMemCpy(Tmp, RegAddr, TySize, false);
>>        RegAddr = Tmp;
>>      }
>> +
>>    } else if (neededSSE == 1) {
>> -    RegAddr = CGF.Builder.CreateGEP(RegAddr, fp_offset);
>> -    RegAddr = CGF.Builder.CreateBitCast(RegAddr,
>> -
>> llvm::PointerType::getUnqual(LTy));
>> +    RegAddr = Address(CGF.Builder.CreateGEP(RegSaveArea, fp_offset),
>> +                      CharUnits::fromQuantity(16));
>> +    RegAddr = CGF.Builder.CreateElementBitCast(RegAddr, LTy);
>>    } else {
>>      assert(neededSSE == 2 && "Invalid number of needed registers!");
>>      // SSE registers are spaced 16 bytes apart in the register save
>>      // area, we need to collect the two eightbytes together.
>> -    llvm::Value *RegAddrLo = CGF.Builder.CreateGEP(RegAddr, fp_offset);
>> -    llvm::Value *RegAddrHi = CGF.Builder.CreateConstGEP1_32(RegAddrLo,
>> 16);
>> +    // The ABI isn't explicit about this, but it seems reasonable
>> +    // to assume that the slots are 16-byte aligned, since the stack is
>> +    // naturally 16-byte aligned and the prologue is expected to store
>> +    // all the SSE registers to the RSA.
>> +    Address RegAddrLo = Address(CGF.Builder.CreateGEP(RegSaveArea,
>> fp_offset),
>> +                                CharUnits::fromQuantity(16));
>> +    Address RegAddrHi =
>> +      CGF.Builder.CreateConstInBoundsByteGEP(RegAddrLo,
>> +
>>  CharUnits::fromQuantity(16));
>>      llvm::Type *DoubleTy = CGF.DoubleTy;
>> -    llvm::Type *DblPtrTy =
>> -      llvm::PointerType::getUnqual(DoubleTy);
>>      llvm::StructType *ST = llvm::StructType::get(DoubleTy, DoubleTy,
>> nullptr);
>> -    llvm::Value *V, *Tmp = CGF.CreateMemTemp(Ty);
>> -    Tmp = CGF.Builder.CreateBitCast(Tmp, ST->getPointerTo());
>> -    V = CGF.Builder.CreateLoad(CGF.Builder.CreateBitCast(RegAddrLo,
>> -                                                         DblPtrTy));
>> -    CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(ST, Tmp, 0));
>> -    V = CGF.Builder.CreateLoad(CGF.Builder.CreateBitCast(RegAddrHi,
>> -                                                         DblPtrTy));
>> -    CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(ST, Tmp, 1));
>> -    RegAddr = CGF.Builder.CreateBitCast(Tmp,
>> -
>> llvm::PointerType::getUnqual(LTy));
>> +    llvm::Value *V;
>> +    Address Tmp = CGF.CreateMemTemp(Ty);
>> +    Tmp = CGF.Builder.CreateElementBitCast(Tmp, ST);
>> +    V = CGF.Builder.CreateLoad(
>> +                   CGF.Builder.CreateElementBitCast(RegAddrLo,
>> DoubleTy));
>> +    CGF.Builder.CreateStore(V,
>> +                   CGF.Builder.CreateStructGEP(Tmp, 0,
>> CharUnits::Zero()));
>> +    V = CGF.Builder.CreateLoad(
>> +                   CGF.Builder.CreateElementBitCast(RegAddrHi,
>> DoubleTy));
>> +    CGF.Builder.CreateStore(V,
>> +          CGF.Builder.CreateStructGEP(Tmp, 1,
>> CharUnits::fromQuantity(8)));
>> +
>> +    RegAddr = CGF.Builder.CreateElementBitCast(Tmp, LTy);
>>    }
>>
>>    // AMD64-ABI 3.5.7p5: Step 5. Set:
>> @@ -3119,15 +3257,13 @@ llvm::Value *X86_64ABIInfo::EmitVAArg(ll
>>    // Emit code to load the value if it was passed in memory.
>>
>>    CGF.EmitBlock(InMemBlock);
>> -  llvm::Value *MemAddr = EmitVAArgFromMemory(VAListAddr, Ty, CGF);
>> +  Address MemAddr = EmitX86_64VAArgFromMemory(CGF, VAListAddr, Ty);
>>
>>    // Return the appropriate result.
>>
>>    CGF.EmitBlock(ContBlock);
>> -  llvm::PHINode *ResAddr = CGF.Builder.CreatePHI(RegAddr->getType(), 2,
>> -                                                 "vaarg.addr");
>> -  ResAddr->addIncoming(RegAddr, InRegBlock);
>> -  ResAddr->addIncoming(MemAddr, InMemBlock);
>> +  Address ResAddr = emitMergePHI(CGF, RegAddr, InRegBlock, MemAddr,
>> InMemBlock,
>> +                                 "vaarg.addr");
>>    return ResAddr;
>>  }
>>
>> @@ -3148,11 +3284,11 @@ ABIArgInfo WinX86_64ABIInfo::classify(Qu
>>    if (RT) {
>>      if (!IsReturnType) {
>>        if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(RT, getCXXABI()))
>> -        return ABIArgInfo::getIndirect(0, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>> +        return getNaturalAlignIndirect(Ty, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>>      }
>>
>>      if (RT->getDecl()->hasFlexibleArrayMember())
>> -      return ABIArgInfo::getIndirect(0, /*ByVal=*/false);
>> +      return getNaturalAlignIndirect(Ty, /*ByVal=*/false);
>>
>>      // FIXME: mingw-w64-gcc emits 128-bit struct as i128
>>      if (Width == 128 &&
>> getTarget().getTriple().isWindowsGNUEnvironment())
>> @@ -3171,7 +3307,8 @@ ABIArgInfo WinX86_64ABIInfo::classify(Qu
>>          return ABIArgInfo::getDirect();
>>        return ABIArgInfo::getExpand();
>>      }
>> -    return ABIArgInfo::getIndirect(Align, /*ByVal=*/false);
>> +    return ABIArgInfo::getIndirect(CharUnits::fromQuantity(Align),
>> +                                   /*ByVal=*/false);
>>    }
>>
>>
>> @@ -3187,7 +3324,7 @@ ABIArgInfo WinX86_64ABIInfo::classify(Qu
>>      // MS x64 ABI requirement: "Any argument that doesn't fit in 8
>> bytes, or is
>>      // not 1, 2, 4, or 8 bytes, must be passed by reference."
>>      if (Width > 64 || !llvm::isPowerOf2_64(Width))
>> -      return ABIArgInfo::getIndirect(0, /*ByVal=*/false);
>> +      return getNaturalAlignIndirect(Ty, /*ByVal=*/false);
>>
>>      // Otherwise, coerce it to a small integer.
>>      return ABIArgInfo::getDirect(llvm::IntegerType::get(getVMContext(),
>> Width));
>> @@ -3217,26 +3354,12 @@ void WinX86_64ABIInfo::computeInfo(CGFun
>>      I.info = classify(I.type, FreeSSERegs, false);
>>  }
>>
>> -llvm::Value *WinX86_64ABIInfo::EmitVAArg(llvm::Value *VAListAddr,
>> QualType Ty,
>> -                                      CodeGenFunction &CGF) const {
>> -  llvm::Type *BPP = CGF.Int8PtrPtrTy;
>> -
>> -  CGBuilderTy &Builder = CGF.Builder;
>> -  llvm::Value *VAListAddrAsBPP = Builder.CreateBitCast(VAListAddr, BPP,
>> -                                                       "ap");
>> -  llvm::Value *Addr = Builder.CreateLoad(VAListAddrAsBPP, "ap.cur");
>> -  llvm::Type *PTy =
>> -    llvm::PointerType::getUnqual(CGF.ConvertType(Ty));
>> -  llvm::Value *AddrTyped = Builder.CreateBitCast(Addr, PTy);
>> -
>> -  uint64_t Offset =
>> -    llvm::RoundUpToAlignment(CGF.getContext().getTypeSize(Ty) / 8, 8);
>> -  llvm::Value *NextAddr =
>> -    Builder.CreateGEP(Addr, llvm::ConstantInt::get(CGF.Int32Ty, Offset),
>> -                      "ap.next");
>> -  Builder.CreateStore(NextAddr, VAListAddrAsBPP);
>> -
>> -  return AddrTyped;
>> +Address WinX86_64ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address
>> VAListAddr,
>> +                                    QualType Ty) const {
>> +  return emitVoidPtrVAArg(CGF, VAListAddr, Ty, /*indirect*/ false,
>> +                          CGF.getContext().getTypeInfoInChars(Ty),
>> +                          CharUnits::fromQuantity(8),
>> +                          /*allowHigherAlign*/ false);
>>  }
>>
>>  // PowerPC-32
>> @@ -3246,8 +3369,8 @@ class PPC32_SVR4_ABIInfo : public Defaul
>>  public:
>>    PPC32_SVR4_ABIInfo(CodeGen::CodeGenTypes &CGT) : DefaultABIInfo(CGT) {}
>>
>> -  llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                         CodeGenFunction &CGF) const override;
>> +  Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
>> +                    QualType Ty) const override;
>>  };
>>
>>  class PPC32TargetCodeGenInfo : public TargetCodeGenInfo {
>> @@ -3266,64 +3389,50 @@ public:
>>
>>  }
>>
>> -llvm::Value *PPC32_SVR4_ABIInfo::EmitVAArg(llvm::Value *VAListAddr,
>> -                                           QualType Ty,
>> -                                           CodeGenFunction &CGF) const {
>> +Address PPC32_SVR4_ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address
>> VAList,
>> +                                      QualType Ty) const {
>>    if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
>>      // TODO: Implement this. For now ignore.
>>      (void)CTy;
>> -    return nullptr;
>> +    return Address::invalid();
>>    }
>>
>> +  // struct __va_list_tag {
>> +  //   unsigned char gpr;
>> +  //   unsigned char fpr;
>> +  //   unsigned short reserved;
>> +  //   void *overflow_arg_area;
>> +  //   void *reg_save_area;
>> +  // };
>> +
>>    bool isI64 = Ty->isIntegerType() && getContext().getTypeSize(Ty) == 64;
>>    bool isInt =
>>        Ty->isIntegerType() || Ty->isPointerType() ||
>> Ty->isAggregateType();
>> -  llvm::Type *CharPtr = CGF.Int8PtrTy;
>> -  llvm::Type *CharPtrPtr = CGF.Int8PtrPtrTy;
>> +
>> +  // All aggregates are passed indirectly?  That doesn't seem consistent
>> +  // with the argument-lowering code.
>> +  bool isIndirect = Ty->isAggregateType();
>>
>>    CGBuilderTy &Builder = CGF.Builder;
>> -  llvm::Value *GPRPtr = Builder.CreateBitCast(VAListAddr, CharPtr,
>> "gprptr");
>> -  llvm::Value *GPRPtrAsInt = Builder.CreatePtrToInt(GPRPtr, CGF.Int32Ty);
>> -  llvm::Value *FPRPtrAsInt =
>> -      Builder.CreateAdd(GPRPtrAsInt, Builder.getInt32(1));
>> -  llvm::Value *FPRPtr = Builder.CreateIntToPtr(FPRPtrAsInt, CharPtr);
>> -  llvm::Value *OverflowAreaPtrAsInt =
>> -      Builder.CreateAdd(FPRPtrAsInt, Builder.getInt32(3));
>> -  llvm::Value *OverflowAreaPtr =
>> -      Builder.CreateIntToPtr(OverflowAreaPtrAsInt, CharPtrPtr);
>> -  llvm::Value *RegsaveAreaPtrAsInt =
>> -      Builder.CreateAdd(OverflowAreaPtrAsInt, Builder.getInt32(4));
>> -  llvm::Value *RegsaveAreaPtr =
>> -      Builder.CreateIntToPtr(RegsaveAreaPtrAsInt, CharPtrPtr);
>> -  llvm::Value *GPR = Builder.CreateLoad(GPRPtr, false, "gpr");
>> -  // Align GPR when TY is i64.
>> -  if (isI64) {
>> -    llvm::Value *GPRAnd = Builder.CreateAnd(GPR, Builder.getInt8(1));
>> -    llvm::Value *CC64 = Builder.CreateICmpEQ(GPRAnd, Builder.getInt8(1));
>> -    llvm::Value *GPRPlusOne = Builder.CreateAdd(GPR, Builder.getInt8(1));
>> -    GPR = Builder.CreateSelect(CC64, GPRPlusOne, GPR);
>> -  }
>> -  llvm::Value *FPR = Builder.CreateLoad(FPRPtr, false, "fpr");
>> -  llvm::Value *OverflowArea =
>> -      Builder.CreateLoad(OverflowAreaPtr, false, "overflow_area");
>> -  llvm::Value *OverflowAreaAsInt =
>> -      Builder.CreatePtrToInt(OverflowArea, CGF.Int32Ty);
>> -  llvm::Value *RegsaveArea =
>> -      Builder.CreateLoad(RegsaveAreaPtr, false, "regsave_area");
>> -  llvm::Value *RegsaveAreaAsInt =
>> -      Builder.CreatePtrToInt(RegsaveArea, CGF.Int32Ty);
>>
>> -  llvm::Value *CC =
>> -      Builder.CreateICmpULT(isInt ? GPR : FPR, Builder.getInt8(8),
>> "cond");
>> +  // The calling convention either uses 1-2 GPRs or 1 FPR.
>> +  Address NumRegsAddr = Address::invalid();
>> +  if (isInt) {
>> +    NumRegsAddr = Builder.CreateStructGEP(VAList, 0, CharUnits::Zero(),
>> "gpr");
>> +  } else {
>> +    NumRegsAddr = Builder.CreateStructGEP(VAList, 1, CharUnits::One(),
>> "fpr");
>> +  }
>>
>> -  llvm::Value *RegConstant =
>> -      Builder.CreateMul(isInt ? GPR : FPR, Builder.getInt8(isInt ? 4 :
>> 8));
>> +  llvm::Value *NumRegs = Builder.CreateLoad(NumRegsAddr, "numUsedRegs");
>>
>> -  llvm::Value *OurReg = Builder.CreateAdd(
>> -      RegsaveAreaAsInt, Builder.CreateSExt(RegConstant, CGF.Int32Ty));
>> +  // "Align" the register count when TY is i64.
>> +  if (isI64) {
>> +    NumRegs = Builder.CreateAdd(NumRegs, Builder.getInt8(1));
>> +    NumRegs = Builder.CreateAnd(NumRegs, Builder.getInt8((uint8_t) ~1U));
>> +  }
>>
>> -  if (Ty->isFloatingType())
>> -    OurReg = Builder.CreateAdd(OurReg, Builder.getInt32(32));
>> +  llvm::Value *CC =
>> +      Builder.CreateICmpULT(NumRegs, Builder.getInt8(8), "cond");
>>
>>    llvm::BasicBlock *UsingRegs = CGF.createBasicBlock("using_regs");
>>    llvm::BasicBlock *UsingOverflow =
>> CGF.createBasicBlock("using_overflow");
>> @@ -3331,39 +3440,84 @@ llvm::Value *PPC32_SVR4_ABIInfo::EmitVAA
>>
>>    Builder.CreateCondBr(CC, UsingRegs, UsingOverflow);
>>
>> -  CGF.EmitBlock(UsingRegs);
>> +  llvm::Type *DirectTy = CGF.ConvertType(Ty);
>> +  if (isIndirect) DirectTy = DirectTy->getPointerTo(0);
>>
>> -  llvm::Type *PTy = llvm::PointerType::getUnqual(CGF.ConvertType(Ty));
>> -  llvm::Value *Result1 = Builder.CreateIntToPtr(OurReg, PTy);
>> -  // Increase the GPR/FPR indexes.
>> -  if (isInt) {
>> -    GPR = Builder.CreateAdd(GPR, Builder.getInt8(isI64 ? 2 : 1));
>> -    Builder.CreateStore(GPR, GPRPtr);
>> -  } else {
>> -    FPR = Builder.CreateAdd(FPR, Builder.getInt8(1));
>> -    Builder.CreateStore(FPR, FPRPtr);
>> -  }
>> -  CGF.EmitBranch(Cont);
>> -
>> -  CGF.EmitBlock(UsingOverflow);
>> +  // Case 1: consume registers.
>> +  Address RegAddr = Address::invalid();
>> +  {
>> +    CGF.EmitBlock(UsingRegs);
>> +
>> +    Address RegSaveAreaPtr =
>> +      Builder.CreateStructGEP(VAList, 4, CharUnits::fromQuantity(8));
>> +    RegAddr = Address(Builder.CreateLoad(RegSaveAreaPtr),
>> +                      CharUnits::fromQuantity(8));
>> +    assert(RegAddr.getElementType() == CGF.Int8Ty);
>> +
>> +    // Floating-point registers start after the general-purpose
>> registers.
>> +    if (!isInt) {
>> +      RegAddr = Builder.CreateConstInBoundsByteGEP(RegAddr,
>> +
>>  CharUnits::fromQuantity(32));
>> +    }
>> +
>> +    // Get the address of the saved value by scaling the number of
>> +    // registers we've used by the number of
>> +    CharUnits RegSize = CharUnits::fromQuantity(isInt ? 4 : 8);
>> +    llvm::Value *RegOffset =
>> +      Builder.CreateMul(NumRegs, Builder.getInt8(RegSize.getQuantity()));
>> +    RegAddr = Address(Builder.CreateInBoundsGEP(CGF.Int8Ty,
>> +                                            RegAddr.getPointer(),
>> RegOffset),
>> +
>> RegAddr.getAlignment().alignmentOfArrayElement(RegSize));
>> +    RegAddr = Builder.CreateElementBitCast(RegAddr, DirectTy);
>> +
>> +    // Increase the used-register count.
>> +    NumRegs = Builder.CreateAdd(NumRegs, Builder.getInt8(isI64 ? 2 : 1));
>> +    Builder.CreateStore(NumRegs, NumRegsAddr);
>> +
>> +    CGF.EmitBranch(Cont);
>> +  }
>> +
>> +  // Case 2: consume space in the overflow area.
>> +  Address MemAddr = Address::invalid();
>> +  {
>> +    CGF.EmitBlock(UsingOverflow);
>> +
>> +    // Everything in the overflow area is rounded up to a size of at
>> least 4.
>> +    CharUnits OverflowAreaAlign = CharUnits::fromQuantity(4);
>> +
>> +    CharUnits Size;
>> +    if (!isIndirect) {
>> +      auto TypeInfo = CGF.getContext().getTypeInfoInChars(Ty);
>> +      Size = TypeInfo.first.RoundUpToAlignment(OverflowAreaAlign);
>> +    } else {
>> +      Size = CGF.getPointerSize();
>> +    }
>>
>> -  // Increase the overflow area.
>> -  llvm::Value *Result2 = Builder.CreateIntToPtr(OverflowAreaAsInt, PTy);
>> -  OverflowAreaAsInt =
>> -      Builder.CreateAdd(OverflowAreaAsInt, Builder.getInt32(isInt ? 4 :
>> 8));
>> -  Builder.CreateStore(Builder.CreateIntToPtr(OverflowAreaAsInt, CharPtr),
>> -                      OverflowAreaPtr);
>> -  CGF.EmitBranch(Cont);
>> +    Address OverflowAreaAddr =
>> +      Builder.CreateStructGEP(VAList, 3, CharUnits::fromQuantity(4));
>> +    Address OverflowArea(Builder.CreateLoad(OverflowAreaAddr),
>> +                         OverflowAreaAlign);
>> +
>> +    // The current address is the address of the varargs element.
>> +    // FIXME: do we not need to round up to alignment?
>> +    MemAddr = Builder.CreateElementBitCast(OverflowArea, DirectTy);
>> +
>> +    // Increase the overflow area.
>> +    OverflowArea = Builder.CreateConstInBoundsByteGEP(OverflowArea,
>> Size);
>> +    Builder.CreateStore(OverflowArea.getPointer(), OverflowAreaAddr);
>> +    CGF.EmitBranch(Cont);
>> +  }
>>
>>    CGF.EmitBlock(Cont);
>>
>> -  llvm::PHINode *Result = CGF.Builder.CreatePHI(PTy, 2, "vaarg.addr");
>> -  Result->addIncoming(Result1, UsingRegs);
>> -  Result->addIncoming(Result2, UsingOverflow);
>> -
>> -  if (Ty->isAggregateType()) {
>> -    llvm::Value *AGGPtr = Builder.CreateBitCast(Result, CharPtrPtr,
>> "aggrptr");
>> -    return Builder.CreateLoad(AGGPtr, false, "aggr");
>> +  // Merge the cases with a phi.
>> +  Address Result = emitMergePHI(CGF, RegAddr, UsingRegs, MemAddr,
>> UsingOverflow,
>> +                                "vaarg.addr");
>> +
>> +  // Load the pointer if the argument was passed indirectly.
>> +  if (isIndirect) {
>> +    Result = Address(Builder.CreateLoad(Result, "aggr"),
>> +                     getContext().getTypeAlignInChars(Ty));
>>    }
>>
>>    return Result;
>> @@ -3459,7 +3613,7 @@ public:
>>      : DefaultABIInfo(CGT), Kind(Kind), HasQPX(HasQPX) {}
>>
>>    bool isPromotableTypeForABI(QualType Ty) const;
>> -  bool isAlignedParamType(QualType Ty, bool &Align32) const;
>> +  CharUnits getParamTypeAlignment(QualType Ty) const;
>>
>>    ABIArgInfo classifyReturnType(QualType RetTy) const;
>>    ABIArgInfo classifyArgumentType(QualType Ty) const;
>> @@ -3496,8 +3650,8 @@ public:
>>      }
>>    }
>>
>> -  llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                         CodeGenFunction &CGF) const override;
>> +  Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
>> +                    QualType Ty) const override;
>>  };
>>
>>  class PPC64_SVR4_TargetCodeGenInfo : public TargetCodeGenInfo {
>> @@ -3557,12 +3711,9 @@ PPC64_SVR4_ABIInfo::isPromotableTypeForA
>>    return false;
>>  }
>>
>> -/// isAlignedParamType - Determine whether a type requires 16-byte
>> -/// alignment in the parameter area.
>> -bool
>> -PPC64_SVR4_ABIInfo::isAlignedParamType(QualType Ty, bool &Align32) const
>> {
>> -  Align32 = false;
>> -
>> +/// isAlignedParamType - Determine whether a type requires 16-byte or
>> +/// higher alignment in the parameter area.  Always returns at least 8.
>> +CharUnits PPC64_SVR4_ABIInfo::getParamTypeAlignment(QualType Ty) const {
>>    // Complex types are passed just like their elements.
>>    if (const ComplexType *CTy = Ty->getAs<ComplexType>())
>>      Ty = CTy->getElementType();
>> @@ -3571,11 +3722,11 @@ PPC64_SVR4_ABIInfo::isAlignedParamType(Q
>>    // passed via reference, smaller types are not aligned).
>>    if (IsQPXVectorTy(Ty)) {
>>      if (getContext().getTypeSize(Ty) > 128)
>> -      Align32 = true;
>> +      return CharUnits::fromQuantity(32);
>>
>> -    return true;
>> +    return CharUnits::fromQuantity(16);
>>    } else if (Ty->isVectorType()) {
>> -    return getContext().getTypeSize(Ty) == 128;
>> +    return CharUnits::fromQuantity(getContext().getTypeSize(Ty) == 128 ?
>> 16 : 8);
>>    }
>>
>>    // For single-element float/vector structs, we consider the whole type
>> @@ -3600,22 +3751,22 @@ PPC64_SVR4_ABIInfo::isAlignedParamType(Q
>>    // With special case aggregates, only vector base types need alignment.
>>    if (AlignAsType && IsQPXVectorTy(AlignAsType)) {
>>      if (getContext().getTypeSize(AlignAsType) > 128)
>> -      Align32 = true;
>> +      return CharUnits::fromQuantity(32);
>>
>> -    return true;
>> +    return CharUnits::fromQuantity(16);
>>    } else if (AlignAsType) {
>> -    return AlignAsType->isVectorType();
>> +    return CharUnits::fromQuantity(AlignAsType->isVectorType() ? 16 : 8);
>>    }
>>
>>    // Otherwise, we only need alignment for any aggregate type that
>>    // has an alignment requirement of >= 16 bytes.
>>    if (isAggregateTypeForABI(Ty) && getContext().getTypeAlign(Ty) >= 128)
>> {
>>      if (HasQPX && getContext().getTypeAlign(Ty) >= 256)
>> -      Align32 = true;
>> -    return true;
>> +      return CharUnits::fromQuantity(32);
>> +    return CharUnits::fromQuantity(16);
>>    }
>>
>> -  return false;
>> +  return CharUnits::fromQuantity(8);
>>  }
>>
>>  /// isHomogeneousAggregate - Return true if a type is an ELFv2
>> homogeneous
>> @@ -3748,7 +3899,7 @@ PPC64_SVR4_ABIInfo::classifyArgumentType
>>    if (Ty->isVectorType() && !IsQPXVectorTy(Ty)) {
>>      uint64_t Size = getContext().getTypeSize(Ty);
>>      if (Size > 128)
>> -      return ABIArgInfo::getIndirect(0, /*ByVal=*/false);
>> +      return getNaturalAlignIndirect(Ty, /*ByVal=*/false);
>>      else if (Size < 128) {
>>        llvm::Type *CoerceTy = llvm::IntegerType::get(getVMContext(),
>> Size);
>>        return ABIArgInfo::getDirect(CoerceTy);
>> @@ -3757,12 +3908,10 @@ PPC64_SVR4_ABIInfo::classifyArgumentType
>>
>>    if (isAggregateTypeForABI(Ty)) {
>>      if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, getCXXABI()))
>> -      return ABIArgInfo::getIndirect(0, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>> +      return getNaturalAlignIndirect(Ty, RAA ==
>> CGCXXABI::RAA_DirectInMemory);
>>
>> -    bool Align32;
>> -    uint64_t ABIAlign = isAlignedParamType(Ty, Align32) ?
>> -                          (Align32 ? 32 : 16) : 8;
>> -    uint64_t TyAlign = getContext().getTypeAlign(Ty) / 8;
>> +    uint64_t ABIAlign = getParamTypeAlignment(Ty).getQuantity();
>> +    uint64_t TyAlign =
>> getContext().getTypeAlignInChars(Ty).getQuantity();
>>
>>      // ELFv2 homogeneous aggregates are passed as array types.
>>      const Type *Base = nullptr;
>> @@ -3800,7 +3949,8 @@ PPC64_SVR4_ABIInfo::classifyArgumentType
>>      }
>>
>>      // All other aggregates are passed ByVal.
>> -    return ABIArgInfo::getIndirect(ABIAlign, /*ByVal=*/true,
>> +    return ABIArgInfo::getIndirect(CharUnits::fromQuantity(ABIAlign),
>> +                                   /*ByVal=*/true,
>>                                     /*Realign=*/TyAlign > ABIAlign);
>>    }
>>
>> @@ -3821,7 +3971,7 @@ PPC64_SVR4_ABIInfo::classifyReturnType(Q
>>    if (RetTy->isVectorType() && !IsQPXVectorTy(RetTy)) {
>>      uint64_t Size = getContext().getTypeSize(RetTy);
>>      if (Size > 128)
>> -      return ABIArgInfo::getIndirect(0);
>> +      return getNaturalAlignIndirect(RetTy);
>>      else if (Size < 128) {
>>        llvm::Type *CoerceTy = llvm::IntegerType::get(getVMContext(),
>> Size);
>>        return ABIArgInfo::getDirect(CoerceTy);
>> @@ -3856,7 +4006,7 @@ PPC64_SVR4_ABIInfo::classifyReturnType(Q
>>      }
>>
>>      // All other aggregates are returned indirectly.
>> -    return ABIArgInfo::getIndirect(0);
>> +    return getNaturalAlignIndirect(RetTy);
>>    }
>>
>>    return (isPromotableTypeForABI(RetTy) ?
>> @@ -3864,47 +4014,12 @@ PPC64_SVR4_ABIInfo::classifyReturnType(Q
>>  }
>>
>>  // Based on ARMABIInfo::EmitVAArg, adjusted for 64-bit machine.
>> -llvm::Value *PPC64_SVR4_ABIInfo::EmitVAArg(llvm::Value *VAListAddr,
>> -                                           QualType Ty,
>> -                                           CodeGenFunction &CGF) const {
>> -  llvm::Type *BP = CGF.Int8PtrTy;
>> -  llvm::Type *BPP = CGF.Int8PtrPtrTy;
>> -
>> -  CGBuilderTy &Builder = CGF.Builder;
>> -  llvm::Value *VAListAddrAsBPP = Builder.CreateBitCast(VAListAddr, BPP,
>> "ap");
>> -  llvm::Value *Addr = Builder.CreateLoad(VAListAddrAsBPP, "ap.cur");
>> -
>> -  // Handle types that require 16-byte alignment in the parameter save
>> area.
>> -  bool Align32;
>> -  if (isAlignedParamType(Ty, Align32)) {
>> -    llvm::Value *AddrAsInt = Builder.CreatePtrToInt(Addr, CGF.Int64Ty);
>> -    AddrAsInt = Builder.CreateAdd(AddrAsInt,
>> -                                  Builder.getInt64(Align32 ? 31 : 15));
>> -    AddrAsInt = Builder.CreateAnd(AddrAsInt,
>> -                                  Builder.getInt64(Align32 ? -32 : -16));
>> -    Addr = Builder.CreateIntToPtr(AddrAsInt, BP, "ap.align");
>> -  }
>> -
>> -  // Update the va_list pointer.  The pointer should be bumped by the
>> -  // size of the object.  We can trust getTypeSize() except for a complex
>> -  // type whose base type is smaller than a doubleword.  For these, the
>> -  // size of the object is 16 bytes; see below for further explanation.
>> -  unsigned SizeInBytes = CGF.getContext().getTypeSize(Ty) / 8;
>> -  QualType BaseTy;
>> -  unsigned CplxBaseSize = 0;
>> -
>> -  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
>> -    BaseTy = CTy->getElementType();
>> -    CplxBaseSize = CGF.getContext().getTypeSize(BaseTy) / 8;
>> -    if (CplxBaseSize < 8)
>> -      SizeInBytes = 16;
>> -  }
>> +Address PPC64_SVR4_ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address
>> VAListAddr,
>> +                                      QualType Ty) const {
>> +  auto TypeInfo = getContext().getTypeInfoInChars(Ty);
>> +  TypeInfo.second = getParamTypeAlignment(Ty);
>>
>> -  unsigned Offset = llvm::RoundUpToAlignment(SizeInBytes, 8);
>> -  llvm::Value *NextAddr =
>> -    Builder.CreateGEP(Addr, llvm::ConstantInt::get(CGF.Int64Ty, Offset),
>> -                      "ap.next");
>> -  Builder.CreateStore(NextAddr, VAListAddrAsBPP);
>> +  CharUnits SlotSize = CharUnits::fromQuantity(8);
>>
>>    // If we have a complex type and the base type is smaller than 8 bytes,
>>    // the ABI calls for the real and imaginary parts to be right-adjusted
>> @@ -3912,44 +4027,40 @@ llvm::Value *PPC64_SVR4_ABIInfo::EmitVAA
>>    // pointer to a structure with the two parts packed tightly.  So
>> generate
>>    // loads of the real and imaginary parts relative to the va_list
>> pointer,
>>    // and store them to a temporary structure.
>> -  if (CplxBaseSize && CplxBaseSize < 8) {
>> -    llvm::Value *RealAddr = Builder.CreatePtrToInt(Addr, CGF.Int64Ty);
>> -    llvm::Value *ImagAddr = RealAddr;
>> -    if (CGF.CGM.getDataLayout().isBigEndian()) {
>> -      RealAddr =
>> -          Builder.CreateAdd(RealAddr, Builder.getInt64(8 -
>> CplxBaseSize));
>> -      ImagAddr =
>> -          Builder.CreateAdd(ImagAddr, Builder.getInt64(16 -
>> CplxBaseSize));
>> -    } else {
>> -      ImagAddr = Builder.CreateAdd(ImagAddr, Builder.getInt64(8));
>> +  if (const ComplexType *CTy = Ty->getAs<ComplexType>()) {
>> +    CharUnits EltSize = TypeInfo.first / 2;
>> +    if (EltSize < SlotSize) {
>> +      Address Addr = emitVoidPtrDirectVAArg(CGF, VAListAddr, CGF.Int8Ty,
>> +                                            SlotSize * 2, SlotSize,
>> +                                            SlotSize, /*AllowHigher*/
>> true);
>> +
>> +      Address RealAddr = Addr;
>> +      Address ImagAddr = RealAddr;
>> +      if (CGF.CGM.getDataLayout().isBigEndian()) {
>> +        RealAddr = CGF.Builder.CreateConstInBoundsByteGEP(RealAddr,
>> +                                                          SlotSize -
>> EltSize);
>> +        ImagAddr = CGF.Builder.CreateConstInBoundsByteGEP(ImagAddr,
>> +                                                      2 * SlotSize -
>> EltSize);
>> +      } else {
>> +        ImagAddr = CGF.Builder.CreateConstInBoundsByteGEP(RealAddr,
>> SlotSize);
>> +      }
>> +
>> +      llvm::Type *EltTy = CGF.ConvertTypeForMem(CTy->getElementType());
>> +      RealAddr = CGF.Builder.CreateElementBitCast(RealAddr, EltTy);
>> +      ImagAddr = CGF.Builder.CreateElementBitCast(ImagAddr, EltTy);
>> +      llvm::Value *Real = CGF.Builder.CreateLoad(RealAddr, ".vareal");
>> +      llvm::Value *Imag = CGF.Builder.CreateLoad(ImagAddr, ".vaimag");
>> +
>> +      Address Temp = CGF.CreateMemTemp(Ty, "vacplx");
>> +      CGF.EmitStoreOfComplex({Real, Imag}, CGF.MakeAddrLValue(Temp, Ty),
>> +                             /*init*/ true);
>> +      return Temp;
>>      }
>> -    llvm::Type *PBaseTy =
>> llvm::PointerType::getUnqual(CGF.ConvertType(BaseTy));
>> -    RealAddr = Builder.CreateIntToPtr(RealAddr, PBaseTy);
>> -    ImagAddr = Builder.CreateIntToPtr(ImagAddr, PBaseTy);
>> -    llvm::Value *Real = Builder.CreateLoad(RealAddr, false, ".vareal");
>> -    llvm::Value *Imag = Builder.CreateLoad(ImagAddr, false, ".vaimag");
>> -    llvm::AllocaInst *Ptr =
>> -        CGF.CreateTempAlloca(CGT.ConvertTypeForMem(Ty), "vacplx");
>> -    llvm::Value *RealPtr =
>> -        Builder.CreateStructGEP(Ptr->getAllocatedType(), Ptr, 0,
>> ".real");
>> -    llvm::Value *ImagPtr =
>> -        Builder.CreateStructGEP(Ptr->getAllocatedType(), Ptr, 1,
>> ".imag");
>> -    Builder.CreateStore(Real, RealPtr, false);
>> -    Builder.CreateStore(Imag, ImagPtr, false);
>> -    return Ptr;
>> -  }
>> -
>> -  // If the argument is smaller than 8 bytes, it is right-adjusted in
>> -  // its doubleword slot.  Adjust the pointer to pick it up from the
>> -  // correct offset.
>> -  if (SizeInBytes < 8 && CGF.CGM.getDataLayout().isBigEndian()) {
>> -    llvm::Value *AddrAsInt = Builder.CreatePtrToInt(Addr, CGF.Int64Ty);
>> -    AddrAsInt = Builder.CreateAdd(AddrAsInt, Builder.getInt64(8 -
>> SizeInBytes));
>> -    Addr = Builder.CreateIntToPtr(AddrAsInt, BP);
>>    }
>>
>> -  llvm::Type *PTy = llvm::PointerType::getUnqual(CGF.ConvertType(Ty));
>> -  return Builder.CreateBitCast(Addr, PTy);
>> +  // Otherwise, just use the general rule.
>> +  return emitVoidPtrVAArg(CGF, VAListAddr, Ty, /*Indirect*/ false,
>> +                          TypeInfo, SlotSize, /*AllowHigher*/ true);
>>  }
>>
>>  static bool
>> @@ -4047,14 +4158,14 @@ private:
>>        it.info = classifyArgumentType(it.type);
>>    }
>>
>> -  llvm::Value *EmitDarwinVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                               CodeGenFunction &CGF) const;
>> +  Address EmitDarwinVAArg(Address VAListAddr, QualType Ty,
>> +                          CodeGenFunction &CGF) const;
>>
>> -  llvm::Value *EmitAAPCSVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                              CodeGenFunction &CGF) const;
>> +  Address EmitAAPCSVAArg(Address VAListAddr, QualType Ty,
>> +                         CodeGenFunction &CGF) const;
>>
>> -  llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
>> -                         CodeGenFunction &CGF) const override {
>> +  Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
>> +                    QualType Ty) const override {
>>      return isDarwinPCS() ? EmitDarwinVAArg(VAListAddr, Ty, CGF)
>>                           : EmitAAPCSVAArg(VAListAddr, Ty, CGF);
>>    }
>> @@ -4097,7 +4208,7 @@ ABIArgInfo AArch64ABIInfo::classifyArgum
>>            llvm::VectorType::get(llvm::Type::getInt32Ty(getVMContext()),
>> 4);
>>        return ABIArgInfo::getDirect(ResType);
>>      }
>> -    return ABIArgInfo::getIndirect(0, /*ByVal=*/false);
>> +    return getNaturalAlignIndirect(Ty, /*ByVal=*/false);
>>    }
>>
>>    if (!isAggregateTypeForABI(Ty)) {
>> @@ -4113,8 +4224,8 @@ ABIArgInfo AArch64ABIInfo::classifyArgum
>>    // Structures with either a non-trivial destructor or a non-trivial
>>    // copy constructor are always indirect.
>>    if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, getCXXABI())) {
>> -    return ABIArgInfo::getIndirect(0, /*ByVal=*/RAA ==
>> -                                   CGCXXABI::RAA_DirectInMemory);
>> +    return getNaturalAlignIndirect(Ty, /*ByVal=*/RAA ==
>> +                                     CGCXXABI::RAA_DirectInMemory);
>>    }
>>
>>    // Empty records are always ignored on Darwin, but actually passed in
>> C++ mode
>> @@ -4149,7 +4260,7 @@ ABIArgInfo AArch64ABIInfo::classifyArgum
>>      return ABIArgInfo::getDirect(llvm::IntegerType::get(getVMContext(),
>> Size));
>>    }
>>
>> -  return ABIArgInfo::getIndirect(0, /*ByVal=*/false);
>> +  return getNaturalAlignIndirect(Ty, /*ByVal=*/false);
>>  }
>>
>>  ABIArgInfo AArch64ABIInfo::classifyReturnType(QualType RetTy) const {
>> @@ -4158,7 +4269,7 @@ ABIArgInfo AArch64ABIInfo::classifyRetur
>>
>>    // Large vector types should be returned via memory.
>>    if (RetTy->isVectorType() && getContext().getTypeSize(RetTy) > 128)
>> -    return ABIArgInfo::getIndirect(0);
>> +    return getNaturalAlignIndirect(RetTy);
>>
>>    if (!isAggregateTypeForABI(RetTy)) {
>>      // Treat an enum type as its underlying type.
>> @@ -4194,7 +4305,7 @@ ABIArgInfo AArch64ABIInfo::classifyRetur
>>      return ABIArgInfo::getDirect(llvm::IntegerType::get(getVMContext(),
>> Size));
>>    }
>>
>> -  return ABIArgInfo::getIndirect(0);
>> +  return getNaturalAlignIndirect(RetTy);
>>  }
>>
>>  /// isIllegalVectorType - check whether the vector type is legal for
>> AArch64.
>> @@ -4232,7 +4343,7 @@ bool AArch64ABIInfo::isHomogeneousAggreg
>>    return Members <= 4;
>>  }
>>
>> -llvm::Value *AArch64ABIInfo::EmitAAPCSVAArg(llvm::Value *VAListAddr,
>> +Address AArch64ABIInfo::EmitAAPCSVAArg(Address VAListAddr,
>>                                              QualType Ty,
>>                                              CodeGenFunction &CGF) const {
>>    ABIArgInfo AI = classifyArgumentType(Ty);
>> @@ -4266,24 +4377,32 @@ llvm::Value *AArch64ABIInfo::EmitAAPCSVA
>>    llvm::BasicBlock *InRegBlock = CGF.createBasicBlock("vaarg.in_reg");
>>    llvm::BasicBlock *OnStackBlock =
>> CGF.createBasicBlock("vaarg.on_stack");
>>    llvm::BasicBlock *ContBlock = CGF.createBasicBlock("vaarg.end");
>> -  auto &Ctx = CGF.getContext();
>>
>> -  llvm::Value *reg_offs_p = nullptr, *reg_offs = nullptr;
>> +  auto TyInfo = getContext().getTypeInfoInChars(Ty);
>> +  CharUnits TyAlign = TyInfo.second;
>> +
>> +  Address reg_offs_p = Address::invalid();
>> +  llvm::Value *reg_offs = nullptr;
>>    int reg_top_index;
>> -  int RegSize = IsIndirect ? 8 : getContext().getTypeSize(Ty) / 8;
>> +  CharUnits reg_top_offset;
>> +  int RegSize = IsIndirect ? 8 : TyInfo.first.getQuantity();
>>    if (!IsFPR) {
>>      // 3 is the field number of __gr_offs
>>      reg_offs_p =
>> -        CGF.Builder.CreateStructGEP(nullptr, VAListAddr, 3, "gr_offs_p");
>> +        CGF.Builder.CreateStructGEP(VAListAddr, 3,
>> CharUnits::fromQuantity(24),
>> +                                    "gr_offs_p");
>>      reg_offs = CGF.Builder.CreateLoad(reg_offs_p, "gr_offs");
>>      reg_top_index = 1; // field number for __gr_top
>> +    reg_top_offset = CharUnits::fromQuantity(8);
>>      RegSize = llvm::RoundUpToAlignment(RegSize, 8);
>>    } else {
>>      // 4 is the field number of __vr_offs.
>>      reg_offs_p =
>> -        CGF.Builder.CreateStructGEP(nullptr, VAListAddr, 4, "vr_offs_p");
>> +        CGF.Builder.CreateStructGEP(VAListAddr, 4,
>> CharUnits::fromQuantity(28),
>> +                                    "vr_offs_p");
>>      reg_offs = CGF.Builder.CreateLoad(reg_offs_p, "vr_offs");
>>      reg_top_index = 2; // field number for __vr_top
>> +    reg_top_offset = CharUnits::fromQuantity(16);
>>      RegSize = 16 * NumRegs;
>>    }
>>
>> @@ -4308,8 +4427,8 @@ llvm::Value *AArch64ABIInfo::EmitAAPCSVA
>>    // Integer arguments may need to correct register alignment (for
>> example a
>>    // "struct { __int128 a; };" gets passed in x_2N, x_{2N+1}). In this
>> case we
>>    // align __gr_offs to calculate the potential address.
>> -  if (!IsFPR && !IsIndirect && Ctx.getTypeAlign(Ty) > 64) {
>> -    int Align = Ctx.getTypeAlign(Ty) / 8;
>> +  if (!IsFPR && !IsIndirect && TyAlign.getQuantity() > 8) {
>> +    int Align = TyAlign.getQuantity();
>>
>>      reg_offs = CGF.Builder.CreateAdd(
>>          reg_offs, llvm::ConstantInt::get(CGF.Int32Ty, Align - 1),
>> @@ -4320,6 +4439,9 @@ llvm::Value *AArch64ABIInfo::EmitAAPCSVA
>>    }
>>
>>    // Update the gr_offs/vr_offs pointer for next call to va_arg on this
>> va_list.
>> +  // The fact that this is done unconditionally reflects the fact that
>> +  // allocating an argument to the stack also uses up all the remaining
>> +  // registers of the appropriate kind.
>>    llvm::Value *NewOffset = nullptr;
>>    NewOffset = CGF.Builder.CreateAdd(
>>        reg_offs, llvm::ConstantInt::get(CGF.Int32Ty, RegSize),
>> "new_reg_offs");
>> @@ -4341,13 +4463,14 @@ llvm::Value *AArch64ABIInfo::EmitAAPCSVA
>>    // registers. First start the appropriate block:
>>    CGF.EmitBlock(InRegBlock);
>>
>> -  llvm::Value *reg_top_p = nullptr, *reg_top = nullptr;
>> -  reg_top_p = CGF.Builder.CreateStructGEP(nullptr, VAListAddr,
>> reg_top_index,
>> -                                          "reg_top_p");
>> +  llvm::Value *reg_top = nullptr;
>> +  Address reg_top_p = CGF.Builder.CreateStructGEP(VAListAddr,
>> reg_top_index,
>> +                                                  reg_top_offset,
>> "reg_top_p");
>>    reg_top = CGF.Builder.CreateLoad(reg_top_p, "reg_top");
>> -  llvm::Value *BaseAddr = CGF.Builder.CreateGEP(reg_top, reg_offs);
>> -  llvm::Value *RegAddr = nullptr;
>> -  llvm::Type *MemTy =
>> llvm::PointerType::getUnqual(CGF.ConvertTypeForMem(Ty));
>> +  Address BaseAddr(CGF.Builder.CreateInBoundsGEP(reg_top, reg_offs),
>> +                   CharUnits::fromQuantity(IsFPR ? 16 : 8));
>> +  Address RegAddr = Address::invalid();
>> +  llvm::Type *MemTy = CGF.ConvertTypeForMem(Ty);
>>
>>    if (IsIndirect) {
>>      // If it's been passed indirectly (actually a struct), whatever we
>> find from
>> @@ -4364,43 +4487,45 @@ llvm::Value *AArch64ABIInfo::EmitAAPCSVA
>>      // qN+1, ...). We reload and store into a temporary local variable
>>      // contiguously.
>>      assert(!IsIndirect &&
>
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