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diff --git a/contrib/llvm-project/clang/lib/CodeGen/CGExprConstant.cpp b/contrib/llvm-project/clang/lib/CodeGen/CGExprConstant.cpp
new file mode 100644
index 000000000000..31cf2aef1ba0
--- /dev/null
+++ b/contrib/llvm-project/clang/lib/CodeGen/CGExprConstant.cpp
@@ -0,0 +1,2327 @@
+//===--- CGExprConstant.cpp - Emit LLVM Code from Constant Expressions ----===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code to emit Constant Expr nodes as LLVM code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenFunction.h"
+#include "CGCXXABI.h"
+#include "CGObjCRuntime.h"
+#include "CGRecordLayout.h"
+#include "CodeGenModule.h"
+#include "ConstantEmitter.h"
+#include "TargetInfo.h"
+#include "clang/AST/APValue.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/RecordLayout.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/Basic/Builtins.h"
+#include "llvm/ADT/Sequence.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalVariable.h"
+using namespace clang;
+using namespace CodeGen;
+
+//===----------------------------------------------------------------------===//
+//                            ConstantAggregateBuilder
+//===----------------------------------------------------------------------===//
+
+namespace {
+class ConstExprEmitter;
+
+struct ConstantAggregateBuilderUtils {
+  CodeGenModule &CGM;
+
+  ConstantAggregateBuilderUtils(CodeGenModule &CGM) : CGM(CGM) {}
+
+  CharUnits getAlignment(const llvm::Constant *C) const {
+    return CharUnits::fromQuantity(
+        CGM.getDataLayout().getABITypeAlignment(C->getType()));
+  }
+
+  CharUnits getSize(llvm::Type *Ty) const {
+    return CharUnits::fromQuantity(CGM.getDataLayout().getTypeAllocSize(Ty));
+  }
+
+  CharUnits getSize(const llvm::Constant *C) const {
+    return getSize(C->getType());
+  }
+
+  llvm::Constant *getPadding(CharUnits PadSize) const {
+    llvm::Type *Ty = CGM.Int8Ty;
+    if (PadSize > CharUnits::One())
+      Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity());
+    return llvm::UndefValue::get(Ty);
+  }
+
+  llvm::Constant *getZeroes(CharUnits ZeroSize) const {
+    llvm::Type *Ty = llvm::ArrayType::get(CGM.Int8Ty, ZeroSize.getQuantity());
+    return llvm::ConstantAggregateZero::get(Ty);
+  }
+};
+
+/// Incremental builder for an llvm::Constant* holding a struct or array
+/// constant.
+class ConstantAggregateBuilder : private ConstantAggregateBuilderUtils {
+  /// The elements of the constant. These two arrays must have the same size;
+  /// Offsets[i] describes the offset of Elems[i] within the constant. The
+  /// elements are kept in increasing offset order, and we ensure that there
+  /// is no overlap: Offsets[i+1] >= Offsets[i] + getSize(Elemes[i]).
+  ///
+  /// This may contain explicit padding elements (in order to create a
+  /// natural layout), but need not. Gaps between elements are implicitly
+  /// considered to be filled with undef.
+  llvm::SmallVector<llvm::Constant*, 32> Elems;
+  llvm::SmallVector<CharUnits, 32> Offsets;
+
+  /// The size of the constant (the maximum end offset of any added element).
+  /// May be larger than the end of Elems.back() if we split the last element
+  /// and removed some trailing undefs.
+  CharUnits Size = CharUnits::Zero();
+
+  /// This is true only if laying out Elems in order as the elements of a
+  /// non-packed LLVM struct will give the correct layout.
+  bool NaturalLayout = true;
+
+  bool split(size_t Index, CharUnits Hint);
+  Optional<size_t> splitAt(CharUnits Pos);
+
+  static llvm::Constant *buildFrom(CodeGenModule &CGM,
+                                   ArrayRef<llvm::Constant *> Elems,
+                                   ArrayRef<CharUnits> Offsets,
+                                   CharUnits StartOffset, CharUnits Size,
+                                   bool NaturalLayout, llvm::Type *DesiredTy,
+                                   bool AllowOversized);
+
+public:
+  ConstantAggregateBuilder(CodeGenModule &CGM)
+      : ConstantAggregateBuilderUtils(CGM) {}
+
+  /// Update or overwrite the value starting at \p Offset with \c C.
+  ///
+  /// \param AllowOverwrite If \c true, this constant might overwrite (part of)
+  ///        a constant that has already been added. This flag is only used to
+  ///        detect bugs.
+  bool add(llvm::Constant *C, CharUnits Offset, bool AllowOverwrite);
+
+  /// Update or overwrite the bits starting at \p OffsetInBits with \p Bits.
+  bool addBits(llvm::APInt Bits, uint64_t OffsetInBits, bool AllowOverwrite);
+
+  /// Attempt to condense the value starting at \p Offset to a constant of type
+  /// \p DesiredTy.
+  void condense(CharUnits Offset, llvm::Type *DesiredTy);
+
+  /// Produce a constant representing the entire accumulated value, ideally of
+  /// the specified type. If \p AllowOversized, the constant might be larger
+  /// than implied by \p DesiredTy (eg, if there is a flexible array member).
+  /// Otherwise, the constant will be of exactly the same size as \p DesiredTy
+  /// even if we can't represent it as that type.
+  llvm::Constant *build(llvm::Type *DesiredTy, bool AllowOversized) const {
+    return buildFrom(CGM, Elems, Offsets, CharUnits::Zero(), Size,
+                     NaturalLayout, DesiredTy, AllowOversized);
+  }
+};
+
+template<typename Container, typename Range = std::initializer_list<
+                                 typename Container::value_type>>
+static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
+  assert(BeginOff <= EndOff && "invalid replacement range");
+  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
+}
+
+bool ConstantAggregateBuilder::add(llvm::Constant *C, CharUnits Offset,
+                          bool AllowOverwrite) {
+  // Common case: appending to a layout.
+  if (Offset >= Size) {
+    CharUnits Align = getAlignment(C);
+    CharUnits AlignedSize = Size.alignTo(Align);
+    if (AlignedSize > Offset || Offset.alignTo(Align) != Offset)
+      NaturalLayout = false;
+    else if (AlignedSize < Offset) {
+      Elems.push_back(getPadding(Offset - Size));
+      Offsets.push_back(Size);
+    }
+    Elems.push_back(C);
+    Offsets.push_back(Offset);
+    Size = Offset + getSize(C);
+    return true;
+  }
+
+  // Uncommon case: constant overlaps what we've already created.
+  llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
+  if (!FirstElemToReplace)
+    return false;
+
+  CharUnits CSize = getSize(C);
+  llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + CSize);
+  if (!LastElemToReplace)
+    return false;
+
+  assert((FirstElemToReplace == LastElemToReplace || AllowOverwrite) &&
+         "unexpectedly overwriting field");
+
+  replace(Elems, *FirstElemToReplace, *LastElemToReplace, {C});
+  replace(Offsets, *FirstElemToReplace, *LastElemToReplace, {Offset});
+  Size = std::max(Size, Offset + CSize);
+  NaturalLayout = false;
+  return true;
+}
+
+bool ConstantAggregateBuilder::addBits(llvm::APInt Bits, uint64_t OffsetInBits,
+                              bool AllowOverwrite) {
+  const ASTContext &Context = CGM.getContext();
+  const uint64_t CharWidth = CGM.getContext().getCharWidth();
+
+  // Offset of where we want the first bit to go within the bits of the
+  // current char.
+  unsigned OffsetWithinChar = OffsetInBits % CharWidth;
+
+  // We split bit-fields up into individual bytes. Walk over the bytes and
+  // update them.
+  for (CharUnits OffsetInChars =
+           Context.toCharUnitsFromBits(OffsetInBits - OffsetWithinChar);
+       /**/; ++OffsetInChars) {
+    // Number of bits we want to fill in this char.
+    unsigned WantedBits =
+        std::min((uint64_t)Bits.getBitWidth(), CharWidth - OffsetWithinChar);
+
+    // Get a char containing the bits we want in the right places. The other
+    // bits have unspecified values.
+    llvm::APInt BitsThisChar = Bits;
+    if (BitsThisChar.getBitWidth() < CharWidth)
+      BitsThisChar = BitsThisChar.zext(CharWidth);
+    if (CGM.getDataLayout().isBigEndian()) {
+      // Figure out how much to shift by. We may need to left-shift if we have
+      // less than one byte of Bits left.
+      int Shift = Bits.getBitWidth() - CharWidth + OffsetWithinChar;
+      if (Shift > 0)
+        BitsThisChar.lshrInPlace(Shift);
+      else if (Shift < 0)
+        BitsThisChar = BitsThisChar.shl(-Shift);
+    } else {
+      BitsThisChar = BitsThisChar.shl(OffsetWithinChar);
+    }
+    if (BitsThisChar.getBitWidth() > CharWidth)
+      BitsThisChar = BitsThisChar.trunc(CharWidth);
+
+    if (WantedBits == CharWidth) {
+      // Got a full byte: just add it directly.
+      add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
+          OffsetInChars, AllowOverwrite);
+    } else {
+      // Partial byte: update the existing integer if there is one. If we
+      // can't split out a 1-CharUnit range to update, then we can't add
+      // these bits and fail the entire constant emission.
+      llvm::Optional<size_t> FirstElemToUpdate = splitAt(OffsetInChars);
+      if (!FirstElemToUpdate)
+        return false;
+      llvm::Optional<size_t> LastElemToUpdate =
+          splitAt(OffsetInChars + CharUnits::One());
+      if (!LastElemToUpdate)
+        return false;
+      assert(*LastElemToUpdate - *FirstElemToUpdate < 2 &&
+             "should have at most one element covering one byte");
+
+      // Figure out which bits we want and discard the rest.
+      llvm::APInt UpdateMask(CharWidth, 0);
+      if (CGM.getDataLayout().isBigEndian())
+        UpdateMask.setBits(CharWidth - OffsetWithinChar - WantedBits,
+                           CharWidth - OffsetWithinChar);
+      else
+        UpdateMask.setBits(OffsetWithinChar, OffsetWithinChar + WantedBits);
+      BitsThisChar &= UpdateMask;
+
+      if (*FirstElemToUpdate == *LastElemToUpdate ||
+          Elems[*FirstElemToUpdate]->isNullValue() ||
+          isa<llvm::UndefValue>(Elems[*FirstElemToUpdate])) {
+        // All existing bits are either zero or undef.
+        add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
+            OffsetInChars, /*AllowOverwrite*/ true);
+      } else {
+        llvm::Constant *&ToUpdate = Elems[*FirstElemToUpdate];
+        // In order to perform a partial update, we need the existing bitwise
+        // value, which we can only extract for a constant int.
+        auto *CI = dyn_cast<llvm::ConstantInt>(ToUpdate);
+        if (!CI)
+          return false;
+        // Because this is a 1-CharUnit range, the constant occupying it must
+        // be exactly one CharUnit wide.
+        assert(CI->getBitWidth() == CharWidth && "splitAt failed");
+        assert((!(CI->getValue() & UpdateMask) || AllowOverwrite) &&
+               "unexpectedly overwriting bitfield");
+        BitsThisChar |= (CI->getValue() & ~UpdateMask);
+        ToUpdate = llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar);
+      }
+    }
+
+    // Stop if we've added all the bits.
+    if (WantedBits == Bits.getBitWidth())
+      break;
+
+    // Remove the consumed bits from Bits.
+    if (!CGM.getDataLayout().isBigEndian())
+      Bits.lshrInPlace(WantedBits);
+    Bits = Bits.trunc(Bits.getBitWidth() - WantedBits);
+
+    // The remanining bits go at the start of the following bytes.
+    OffsetWithinChar = 0;
+  }
+
+  return true;
+}
+
+/// Returns a position within Elems and Offsets such that all elements
+/// before the returned index end before Pos and all elements at or after
+/// the returned index begin at or after Pos. Splits elements as necessary
+/// to ensure this. Returns None if we find something we can't split.
+Optional<size_t> ConstantAggregateBuilder::splitAt(CharUnits Pos) {
+  if (Pos >= Size)
+    return Offsets.size();
+
+  while (true) {
+    auto FirstAfterPos = llvm::upper_bound(Offsets, Pos);
+    if (FirstAfterPos == Offsets.begin())
+      return 0;
+
+    // If we already have an element starting at Pos, we're done.
+    size_t LastAtOrBeforePosIndex = FirstAfterPos - Offsets.begin() - 1;
+    if (Offsets[LastAtOrBeforePosIndex] == Pos)
+      return LastAtOrBeforePosIndex;
+
+    // We found an element starting before Pos. Check for overlap.
+    if (Offsets[LastAtOrBeforePosIndex] +
+        getSize(Elems[LastAtOrBeforePosIndex]) <= Pos)
+      return LastAtOrBeforePosIndex + 1;
+
+    // Try to decompose it into smaller constants.
+    if (!split(LastAtOrBeforePosIndex, Pos))
+      return None;
+  }
+}
+
+/// Split the constant at index Index, if possible. Return true if we did.
+/// Hint indicates the location at which we'd like to split, but may be
+/// ignored.
+bool ConstantAggregateBuilder::split(size_t Index, CharUnits Hint) {
+  NaturalLayout = false;
+  llvm::Constant *C = Elems[Index];
+  CharUnits Offset = Offsets[Index];
+
+  if (auto *CA = dyn_cast<llvm::ConstantAggregate>(C)) {
+    replace(Elems, Index, Index + 1,
+            llvm::map_range(llvm::seq(0u, CA->getNumOperands()),
+                            [&](unsigned Op) { return CA->getOperand(Op); }));
+    if (auto *Seq = dyn_cast<llvm::SequentialType>(CA->getType())) {
+      // Array or vector.
+      CharUnits ElemSize = getSize(Seq->getElementType());
+      replace(
+          Offsets, Index, Index + 1,
+          llvm::map_range(llvm::seq(0u, CA->getNumOperands()),
+                          [&](unsigned Op) { return Offset + Op * ElemSize; }));
+    } else {
+      // Must be a struct.
+      auto *ST = cast<llvm::StructType>(CA->getType());
+      const llvm::StructLayout *Layout =
+          CGM.getDataLayout().getStructLayout(ST);
+      replace(Offsets, Index, Index + 1,
+              llvm::map_range(
+                  llvm::seq(0u, CA->getNumOperands()), [&](unsigned Op) {
+                    return Offset + CharUnits::fromQuantity(
+                                        Layout->getElementOffset(Op));
+                  }));
+    }
+    return true;
+  }
+
+  if (auto *CDS = dyn_cast<llvm::ConstantDataSequential>(C)) {
+    // FIXME: If possible, split into two ConstantDataSequentials at Hint.
+    CharUnits ElemSize = getSize(CDS->getElementType());
+    replace(Elems, Index, Index + 1,
+            llvm::map_range(llvm::seq(0u, CDS->getNumElements()),
+                            [&](unsigned Elem) {
+                              return CDS->getElementAsConstant(Elem);
+                            }));
+    replace(Offsets, Index, Index + 1,
+            llvm::map_range(
+                llvm::seq(0u, CDS->getNumElements()),
+                [&](unsigned Elem) { return Offset + Elem * ElemSize; }));
+    return true;
+  }
+
+  if (isa<llvm::ConstantAggregateZero>(C)) {
+    CharUnits ElemSize = getSize(C);
+    assert(Hint > Offset && Hint < Offset + ElemSize && "nothing to split");
+    replace(Elems, Index, Index + 1,
+            {getZeroes(Hint - Offset), getZeroes(Offset + ElemSize - Hint)});
+    replace(Offsets, Index, Index + 1, {Offset, Hint});
+    return true;
+  }
+
+  if (isa<llvm::UndefValue>(C)) {
+    replace(Elems, Index, Index + 1, {});
+    replace(Offsets, Index, Index + 1, {});
+    return true;
+  }
+
+  // FIXME: We could split a ConstantInt if the need ever arose.
+  // We don't need to do this to handle bit-fields because we always eagerly
+  // split them into 1-byte chunks.
+
+  return false;
+}
+
+static llvm::Constant *
+EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
+                  llvm::Type *CommonElementType, unsigned ArrayBound,
+                  SmallVectorImpl<llvm::Constant *> &Elements,
+                  llvm::Constant *Filler);
+
+llvm::Constant *ConstantAggregateBuilder::buildFrom(
+    CodeGenModule &CGM, ArrayRef<llvm::Constant *> Elems,
+    ArrayRef<CharUnits> Offsets, CharUnits StartOffset, CharUnits Size,
+    bool NaturalLayout, llvm::Type *DesiredTy, bool AllowOversized) {
+  ConstantAggregateBuilderUtils Utils(CGM);
+
+  if (Elems.empty())
+    return llvm::UndefValue::get(DesiredTy);
+
+  auto Offset = [&](size_t I) { return Offsets[I] - StartOffset; };
+
+  // If we want an array type, see if all the elements are the same type and
+  // appropriately spaced.
+  if (llvm::ArrayType *ATy = dyn_cast<llvm::ArrayType>(DesiredTy)) {
+    assert(!AllowOversized && "oversized array emission not supported");
+
+    bool CanEmitArray = true;
+    llvm::Type *CommonType = Elems[0]->getType();
+    llvm::Constant *Filler = llvm::Constant::getNullValue(CommonType);
+    CharUnits ElemSize = Utils.getSize(ATy->getElementType());
+    SmallVector<llvm::Constant*, 32> ArrayElements;
+    for (size_t I = 0; I != Elems.size(); ++I) {
+      // Skip zeroes; we'll use a zero value as our array filler.
+      if (Elems[I]->isNullValue())
+        continue;
+
+      // All remaining elements must be the same type.
+      if (Elems[I]->getType() != CommonType ||
+          Offset(I) % ElemSize != 0) {
+        CanEmitArray = false;
+        break;
+      }
+      ArrayElements.resize(Offset(I) / ElemSize + 1, Filler);
+      ArrayElements.back() = Elems[I];
+    }
+
+    if (CanEmitArray) {
+      return EmitArrayConstant(CGM, ATy, CommonType, ATy->getNumElements(),
+                               ArrayElements, Filler);
+    }
+
+    // Can't emit as an array, carry on to emit as a struct.
+  }
+
+  CharUnits DesiredSize = Utils.getSize(DesiredTy);
+  CharUnits Align = CharUnits::One();
+  for (llvm::Constant *C : Elems)
+    Align = std::max(Align, Utils.getAlignment(C));
+  CharUnits AlignedSize = Size.alignTo(Align);
+
+  bool Packed = false;
+  ArrayRef<llvm::Constant*> UnpackedElems = Elems;
+  llvm::SmallVector<llvm::Constant*, 32> UnpackedElemStorage;
+  if ((DesiredSize < AlignedSize && !AllowOversized) ||
+      DesiredSize.alignTo(Align) != DesiredSize) {
+    // The natural layout would be the wrong size; force use of a packed layout.
+    NaturalLayout = false;
+    Packed = true;
+  } else if (DesiredSize > AlignedSize) {
+    // The constant would be too small. Add padding to fix it.
+    UnpackedElemStorage.assign(Elems.begin(), Elems.end());
+    UnpackedElemStorage.push_back(Utils.getPadding(DesiredSize - Size));
+    UnpackedElems = UnpackedElemStorage;
+  }
+
+  // If we don't have a natural layout, insert padding as necessary.
+  // As we go, double-check to see if we can actually just emit Elems
+  // as a non-packed struct and do so opportunistically if possible.
+  llvm::SmallVector<llvm::Constant*, 32> PackedElems;
+  if (!NaturalLayout) {
+    CharUnits SizeSoFar = CharUnits::Zero();
+    for (size_t I = 0; I != Elems.size(); ++I) {
+      CharUnits Align = Utils.getAlignment(Elems[I]);
+      CharUnits NaturalOffset = SizeSoFar.alignTo(Align);
+      CharUnits DesiredOffset = Offset(I);
+      assert(DesiredOffset >= SizeSoFar && "elements out of order");
+
+      if (DesiredOffset != NaturalOffset)
+        Packed = true;
+      if (DesiredOffset != SizeSoFar)
+        PackedElems.push_back(Utils.getPadding(DesiredOffset - SizeSoFar));
+      PackedElems.push_back(Elems[I]);
+      SizeSoFar = DesiredOffset + Utils.getSize(Elems[I]);
+    }
+    // If we're using the packed layout, pad it out to the desired size if
+    // necessary.
+    if (Packed) {
+      assert((SizeSoFar <= DesiredSize || AllowOversized) &&
+             "requested size is too small for contents");
+      if (SizeSoFar < DesiredSize)
+        PackedElems.push_back(Utils.getPadding(DesiredSize - SizeSoFar));
+    }
+  }
+
+  llvm::StructType *STy = llvm::ConstantStruct::getTypeForElements(
+      CGM.getLLVMContext(), Packed ? PackedElems : UnpackedElems, Packed);
+
+  // Pick the type to use.  If the type is layout identical to the desired
+  // type then use it, otherwise use whatever the builder produced for us.
+  if (llvm::StructType *DesiredSTy = dyn_cast<llvm::StructType>(DesiredTy)) {
+    if (DesiredSTy->isLayoutIdentical(STy))
+      STy = DesiredSTy;
+  }
+
+  return llvm::ConstantStruct::get(STy, Packed ? PackedElems : UnpackedElems);
+}
+
+void ConstantAggregateBuilder::condense(CharUnits Offset,
+                                        llvm::Type *DesiredTy) {
+  CharUnits Size = getSize(DesiredTy);
+
+  llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
+  if (!FirstElemToReplace)
+    return;
+  size_t First = *FirstElemToReplace;
+
+  llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + Size);
+  if (!LastElemToReplace)
+    return;
+  size_t Last = *LastElemToReplace;
+
+  size_t Length = Last - First;
+  if (Length == 0)
+    return;
+
+  if (Length == 1 && Offsets[First] == Offset &&
+      getSize(Elems[First]) == Size) {
+    // Re-wrap single element structs if necessary. Otherwise, leave any single
+    // element constant of the right size alone even if it has the wrong type.
+    auto *STy = dyn_cast<llvm::StructType>(DesiredTy);
+    if (STy && STy->getNumElements() == 1 &&
+        STy->getElementType(0) == Elems[First]->getType())
+      Elems[First] = llvm::ConstantStruct::get(STy, Elems[First]);
+    return;
+  }
+
+  llvm::Constant *Replacement = buildFrom(
+      CGM, makeArrayRef(Elems).slice(First, Length),
+      makeArrayRef(Offsets).slice(First, Length), Offset, getSize(DesiredTy),
+      /*known to have natural layout=*/false, DesiredTy, false);
+  replace(Elems, First, Last, {Replacement});
+  replace(Offsets, First, Last, {Offset});
+}
+
+//===----------------------------------------------------------------------===//
+//                            ConstStructBuilder
+//===----------------------------------------------------------------------===//
+
+class ConstStructBuilder {
+  CodeGenModule &CGM;
+  ConstantEmitter &Emitter;
+  ConstantAggregateBuilder &Builder;
+  CharUnits StartOffset;
+
+public:
+  static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
+                                     InitListExpr *ILE, QualType StructTy);
+  static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
+                                     const APValue &Value, QualType ValTy);
+  static bool UpdateStruct(ConstantEmitter &Emitter,
+                           ConstantAggregateBuilder &Const, CharUnits Offset,
+                           InitListExpr *Updater);
+
+private:
+  ConstStructBuilder(ConstantEmitter &Emitter,
+                     ConstantAggregateBuilder &Builder, CharUnits StartOffset)
+      : CGM(Emitter.CGM), Emitter(Emitter), Builder(Builder),
+        StartOffset(StartOffset) {}
+
+  bool AppendField(const FieldDecl *Field, uint64_t FieldOffset,
+                   llvm::Constant *InitExpr, bool AllowOverwrite = false);
+
+  bool AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst,
+                   bool AllowOverwrite = false);
+
+  bool AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
+                      llvm::ConstantInt *InitExpr, bool AllowOverwrite = false);
+
+  bool Build(InitListExpr *ILE, bool AllowOverwrite);
+  bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase,
+             const CXXRecordDecl *VTableClass, CharUnits BaseOffset);
+  llvm::Constant *Finalize(QualType Ty);
+};
+
+bool ConstStructBuilder::AppendField(
+    const FieldDecl *Field, uint64_t FieldOffset, llvm::Constant *InitCst,
+    bool AllowOverwrite) {
+  const ASTContext &Context = CGM.getContext();
+
+  CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
+
+  return AppendBytes(FieldOffsetInChars, InitCst, AllowOverwrite);
+}
+
+bool ConstStructBuilder::AppendBytes(CharUnits FieldOffsetInChars,
+                                     llvm::Constant *InitCst,
+                                     bool AllowOverwrite) {
+  return Builder.add(InitCst, StartOffset + FieldOffsetInChars, AllowOverwrite);
+}
+
+bool ConstStructBuilder::AppendBitField(
+    const FieldDecl *Field, uint64_t FieldOffset, llvm::ConstantInt *CI,
+    bool AllowOverwrite) {
+  uint64_t FieldSize = Field->getBitWidthValue(CGM.getContext());
+  llvm::APInt FieldValue = CI->getValue();
+
+  // Promote the size of FieldValue if necessary
+  // FIXME: This should never occur, but currently it can because initializer
+  // constants are cast to bool, and because clang is not enforcing bitfield
+  // width limits.
+  if (FieldSize > FieldValue.getBitWidth())
+    FieldValue = FieldValue.zext(FieldSize);
+
+  // Truncate the size of FieldValue to the bit field size.
+  if (FieldSize < FieldValue.getBitWidth())
+    FieldValue = FieldValue.trunc(FieldSize);
+
+  return Builder.addBits(FieldValue,
+                         CGM.getContext().toBits(StartOffset) + FieldOffset,
+                         AllowOverwrite);
+}
+
+static bool EmitDesignatedInitUpdater(ConstantEmitter &Emitter,
+                                      ConstantAggregateBuilder &Const,
+                                      CharUnits Offset, QualType Type,
+                                      InitListExpr *Updater) {
+  if (Type->isRecordType())
+    return ConstStructBuilder::UpdateStruct(Emitter, Const, Offset, Updater);
+
+  auto CAT = Emitter.CGM.getContext().getAsConstantArrayType(Type);
+  if (!CAT)
+    return false;
+  QualType ElemType = CAT->getElementType();
+  CharUnits ElemSize = Emitter.CGM.getContext().getTypeSizeInChars(ElemType);
+  llvm::Type *ElemTy = Emitter.CGM.getTypes().ConvertTypeForMem(ElemType);
+
+  llvm::Constant *FillC = nullptr;
+  if (Expr *Filler = Updater->getArrayFiller()) {
+    if (!isa<NoInitExpr>(Filler)) {
+      FillC = Emitter.tryEmitAbstractForMemory(Filler, ElemType);
+      if (!FillC)
+        return false;
+    }
+  }
+
+  unsigned NumElementsToUpdate =
+      FillC ? CAT->getSize().getZExtValue() : Updater->getNumInits();
+  for (unsigned I = 0; I != NumElementsToUpdate; ++I, Offset += ElemSize) {
+    Expr *Init = nullptr;
+    if (I < Updater->getNumInits())
+      Init = Updater->getInit(I);
+
+    if (!Init && FillC) {
+      if (!Const.add(FillC, Offset, true))
+        return false;
+    } else if (!Init || isa<NoInitExpr>(Init)) {
+      continue;
+    } else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init)) {
+      if (!EmitDesignatedInitUpdater(Emitter, Const, Offset, ElemType,
+                                     ChildILE))
+        return false;
+      // Attempt to reduce the array element to a single constant if necessary.
+      Const.condense(Offset, ElemTy);
+    } else {
+      llvm::Constant *Val = Emitter.tryEmitPrivateForMemory(Init, ElemType);
+      if (!Const.add(Val, Offset, true))
+        return false;
+    }
+  }
+
+  return true;
+}
+
+bool ConstStructBuilder::Build(InitListExpr *ILE, bool AllowOverwrite) {
+  RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
+  const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
+
+  unsigned FieldNo = -1;
+  unsigned ElementNo = 0;
+
+  // Bail out if we have base classes. We could support these, but they only
+  // arise in C++1z where we will have already constant folded most interesting
+  // cases. FIXME: There are still a few more cases we can handle this way.
+  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
+    if (CXXRD->getNumBases())
+      return false;
+
+  for (FieldDecl *Field : RD->fields()) {
+    ++FieldNo;
+
+    // If this is a union, skip all the fields that aren't being initialized.
+    if (RD->isUnion() &&
+        !declaresSameEntity(ILE->getInitializedFieldInUnion(), Field))
+      continue;
+
+    // Don't emit anonymous bitfields or zero-sized fields.
+    if (Field->isUnnamedBitfield() || Field->isZeroSize(CGM.getContext()))
+      continue;
+
+    // Get the initializer.  A struct can include fields without initializers,
+    // we just use explicit null values for them.
+    Expr *Init = nullptr;
+    if (ElementNo < ILE->getNumInits())
+      Init = ILE->getInit(ElementNo++);
+    if (Init && isa<NoInitExpr>(Init))
+      continue;
+
+    // When emitting a DesignatedInitUpdateExpr, a nested InitListExpr
+    // represents additional overwriting of our current constant value, and not
+    // a new constant to emit independently.
+    if (AllowOverwrite &&
+        (Field->getType()->isArrayType() || Field->getType()->isRecordType())) {
+      if (auto *SubILE = dyn_cast<InitListExpr>(Init)) {
+        CharUnits Offset = CGM.getContext().toCharUnitsFromBits(
+            Layout.getFieldOffset(FieldNo));
+        if (!EmitDesignatedInitUpdater(Emitter, Builder, StartOffset + Offset,
+                                       Field->getType(), SubILE))
+          return false;
+        // If we split apart the field's value, try to collapse it down to a
+        // single value now.
+        Builder.condense(StartOffset + Offset,
+                         CGM.getTypes().ConvertTypeForMem(Field->getType()));
+        continue;
+      }
+    }
+
+    llvm::Constant *EltInit =
+        Init ? Emitter.tryEmitPrivateForMemory(Init, Field->getType())
+             : Emitter.emitNullForMemory(Field->getType());
+    if (!EltInit)
+      return false;
+
+    if (!Field->isBitField()) {
+      // Handle non-bitfield members.
+      if (!AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit,
+                       AllowOverwrite))
+        return false;
+      // After emitting a non-empty field with [[no_unique_address]], we may
+      // need to overwrite its tail padding.
+      if (Field->hasAttr<NoUniqueAddressAttr>())
+        AllowOverwrite = true;
+    } else {
+      // Otherwise we have a bitfield.
+      if (auto *CI = dyn_cast<llvm::ConstantInt>(EltInit)) {
+        if (!AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI,
+                            AllowOverwrite))
+          return false;
+      } else {
+        // We are trying to initialize a bitfield with a non-trivial constant,
+        // this must require run-time code.
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+namespace {
+struct BaseInfo {
+  BaseInfo(const CXXRecordDecl *Decl, CharUnits Offset, unsigned Index)
+    : Decl(Decl), Offset(Offset), Index(Index) {
+  }
+
+  const CXXRecordDecl *Decl;
+  CharUnits Offset;
+  unsigned Index;
+
+  bool operator<(const BaseInfo &O) const { return Offset < O.Offset; }
+};
+}
+
+bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
+                               bool IsPrimaryBase,
+                               const CXXRecordDecl *VTableClass,
+                               CharUnits Offset) {
+  const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
+
+  if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
+    // Add a vtable pointer, if we need one and it hasn't already been added.
+    if (CD->isDynamicClass() && !IsPrimaryBase) {
+      llvm::Constant *VTableAddressPoint =
+          CGM.getCXXABI().getVTableAddressPointForConstExpr(
+              BaseSubobject(CD, Offset), VTableClass);
+      if (!AppendBytes(Offset, VTableAddressPoint))
+        return false;
+    }
+
+    // Accumulate and sort bases, in order to visit them in address order, which
+    // may not be the same as declaration order.
+    SmallVector<BaseInfo, 8> Bases;
+    Bases.reserve(CD->getNumBases());
+    unsigned BaseNo = 0;
+    for (CXXRecordDecl::base_class_const_iterator Base = CD->bases_begin(),
+         BaseEnd = CD->bases_end(); Base != BaseEnd; ++Base, ++BaseNo) {
+      assert(!Base->isVirtual() && "should not have virtual bases here");
+      const CXXRecordDecl *BD = Base->getType()->getAsCXXRecordDecl();
+      CharUnits BaseOffset = Layout.getBaseClassOffset(BD);
+      Bases.push_back(BaseInfo(BD, BaseOffset, BaseNo));
+    }
+    llvm::stable_sort(Bases);
+
+    for (unsigned I = 0, N = Bases.size(); I != N; ++I) {
+      BaseInfo &Base = Bases[I];
+
+      bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl;
+      Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
+            VTableClass, Offset + Base.Offset);
+    }
+  }
+
+  unsigned FieldNo = 0;
+  uint64_t OffsetBits = CGM.getContext().toBits(Offset);
+
+  bool AllowOverwrite = false;
+  for (RecordDecl::field_iterator Field = RD->field_begin(),
+       FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
+    // If this is a union, skip all the fields that aren't being initialized.
+    if (RD->isUnion() && !declaresSameEntity(Val.getUnionField(), *Field))
+      continue;
+
+    // Don't emit anonymous bitfields or zero-sized fields.
+    if (Field->isUnnamedBitfield() || Field->isZeroSize(CGM.getContext()))
+      continue;
+
+    // Emit the value of the initializer.
+    const APValue &FieldValue =
+      RD->isUnion() ? Val.getUnionValue() : Val.getStructField(FieldNo);
+    llvm::Constant *EltInit =
+      Emitter.tryEmitPrivateForMemory(FieldValue, Field->getType());
+    if (!EltInit)
+      return false;
+
+    if (!Field->isBitField()) {
+      // Handle non-bitfield members.
+      if (!AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
+                       EltInit, AllowOverwrite))
+        return false;
+      // After emitting a non-empty field with [[no_unique_address]], we may
+      // need to overwrite its tail padding.
+      if (Field->hasAttr<NoUniqueAddressAttr>())
+        AllowOverwrite = true;
+    } else {
+      // Otherwise we have a bitfield.
+      if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
+                          cast<llvm::ConstantInt>(EltInit), AllowOverwrite))
+        return false;
+    }
+  }
+
+  return true;
+}
+
+llvm::Constant *ConstStructBuilder::Finalize(QualType Type) {
+  RecordDecl *RD = Type->getAs<RecordType>()->getDecl();
+  llvm::Type *ValTy = CGM.getTypes().ConvertType(Type);
+  return Builder.build(ValTy, RD->hasFlexibleArrayMember());
+}
+
+llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
+                                                InitListExpr *ILE,
+                                                QualType ValTy) {
+  ConstantAggregateBuilder Const(Emitter.CGM);
+  ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
+
+  if (!Builder.Build(ILE, /*AllowOverwrite*/false))
+    return nullptr;
+
+  return Builder.Finalize(ValTy);
+}
+
+llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
+                                                const APValue &Val,
+                                                QualType ValTy) {
+  ConstantAggregateBuilder Const(Emitter.CGM);
+  ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
+
+  const RecordDecl *RD = ValTy->castAs<RecordType>()->getDecl();
+  const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
+  if (!Builder.Build(Val, RD, false, CD, CharUnits::Zero()))
+    return nullptr;
+
+  return Builder.Finalize(ValTy);
+}
+
+bool ConstStructBuilder::UpdateStruct(ConstantEmitter &Emitter,
+                                      ConstantAggregateBuilder &Const,
+                                      CharUnits Offset, InitListExpr *Updater) {
+  return ConstStructBuilder(Emitter, Const, Offset)
+      .Build(Updater, /*AllowOverwrite*/ true);
+}
+
+//===----------------------------------------------------------------------===//
+//                             ConstExprEmitter
+//===----------------------------------------------------------------------===//
+
+static ConstantAddress tryEmitGlobalCompoundLiteral(CodeGenModule &CGM,
+                                                    CodeGenFunction *CGF,
+                                              const CompoundLiteralExpr *E) {
+  CharUnits Align = CGM.getContext().getTypeAlignInChars(E->getType());
+  if (llvm::GlobalVariable *Addr =
+          CGM.getAddrOfConstantCompoundLiteralIfEmitted(E))
+    return ConstantAddress(Addr, Align);
+
+  LangAS addressSpace = E->getType().getAddressSpace();
+
+  ConstantEmitter emitter(CGM, CGF);
+  llvm::Constant *C = emitter.tryEmitForInitializer(E->getInitializer(),
+                                                    addressSpace, E->getType());
+  if (!C) {
+    assert(!E->isFileScope() &&
+           "file-scope compound literal did not have constant initializer!");
+    return ConstantAddress::invalid();
+  }
+
+  auto GV = new llvm::GlobalVariable(CGM.getModule(), C->getType(),
+                                     CGM.isTypeConstant(E->getType(), true),
+                                     llvm::GlobalValue::InternalLinkage,
+                                     C, ".compoundliteral", nullptr,
+                                     llvm::GlobalVariable::NotThreadLocal,
+                    CGM.getContext().getTargetAddressSpace(addressSpace));
+  emitter.finalize(GV);
+  GV->setAlignment(Align.getQuantity());
+  CGM.setAddrOfConstantCompoundLiteral(E, GV);
+  return ConstantAddress(GV, Align);
+}
+
+static llvm::Constant *
+EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
+                  llvm::Type *CommonElementType, unsigned ArrayBound,
+                  SmallVectorImpl<llvm::Constant *> &Elements,
+                  llvm::Constant *Filler) {
+  // Figure out how long the initial prefix of non-zero elements is.
+  unsigned NonzeroLength = ArrayBound;
+  if (Elements.size() < NonzeroLength && Filler->isNullValue())
+    NonzeroLength = Elements.size();
+  if (NonzeroLength == Elements.size()) {
+    while (NonzeroLength > 0 && Elements[NonzeroLength - 1]->isNullValue())
+      --NonzeroLength;
+  }
+
+  if (NonzeroLength == 0)
+    return llvm::ConstantAggregateZero::get(DesiredType);
+
+  // Add a zeroinitializer array filler if we have lots of trailing zeroes.
+  unsigned TrailingZeroes = ArrayBound - NonzeroLength;
+  if (TrailingZeroes >= 8) {
+    assert(Elements.size() >= NonzeroLength &&
+           "missing initializer for non-zero element");
+
+    // If all the elements had the same type up to the trailing zeroes, emit a
+    // struct of two arrays (the nonzero data and the zeroinitializer).
+    if (CommonElementType && NonzeroLength >= 8) {
+      llvm::Constant *Initial = llvm::ConstantArray::get(
+          llvm::ArrayType::get(CommonElementType, NonzeroLength),
+          makeArrayRef(Elements).take_front(NonzeroLength));
+      Elements.resize(2);
+      Elements[0] = Initial;
+    } else {
+      Elements.resize(NonzeroLength + 1);
+    }
+
+    auto *FillerType =
+        CommonElementType ? CommonElementType : DesiredType->getElementType();
+    FillerType = llvm::ArrayType::get(FillerType, TrailingZeroes);
+    Elements.back() = llvm::ConstantAggregateZero::get(FillerType);
+    CommonElementType = nullptr;
+  } else if (Elements.size() != ArrayBound) {
+    // Otherwise pad to the right size with the filler if necessary.
+    Elements.resize(ArrayBound, Filler);
+    if (Filler->getType() != CommonElementType)
+      CommonElementType = nullptr;
+  }
+
+  // If all elements have the same type, just emit an array constant.
+  if (CommonElementType)
+    return llvm::ConstantArray::get(
+        llvm::ArrayType::get(CommonElementType, ArrayBound), Elements);
+
+  // We have mixed types. Use a packed struct.
+  llvm::SmallVector<llvm::Type *, 16> Types;
+  Types.reserve(Elements.size());
+  for (llvm::Constant *Elt : Elements)
+    Types.push_back(Elt->getType());
+  llvm::StructType *SType =
+      llvm::StructType::get(CGM.getLLVMContext(), Types, true);
+  return llvm::ConstantStruct::get(SType, Elements);
+}
+
+// This class only needs to handle arrays, structs and unions. Outside C++11
+// mode, we don't currently constant fold those types.  All other types are
+// handled by constant folding.
+//
+// Constant folding is currently missing support for a few features supported
+// here: CK_ToUnion, CK_ReinterpretMemberPointer, and DesignatedInitUpdateExpr.
+class ConstExprEmitter :
+  public StmtVisitor<ConstExprEmitter, llvm::Constant*, QualType> {
+  CodeGenModule &CGM;
+  ConstantEmitter &Emitter;
+  llvm::LLVMContext &VMContext;
+public:
+  ConstExprEmitter(ConstantEmitter &emitter)
+    : CGM(emitter.CGM), Emitter(emitter), VMContext(CGM.getLLVMContext()) {
+  }
+
+  //===--------------------------------------------------------------------===//
+  //                            Visitor Methods
+  //===--------------------------------------------------------------------===//
+
+  llvm::Constant *VisitStmt(Stmt *S, QualType T) {
+    return nullptr;
+  }
+
+  llvm::Constant *VisitConstantExpr(ConstantExpr *CE, QualType T) {
+    return Visit(CE->getSubExpr(), T);
+  }
+
+  llvm::Constant *VisitParenExpr(ParenExpr *PE, QualType T) {
+    return Visit(PE->getSubExpr(), T);
+  }
+
+  llvm::Constant *
+  VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *PE,
+                                    QualType T) {
+    return Visit(PE->getReplacement(), T);
+  }
+
+  llvm::Constant *VisitGenericSelectionExpr(GenericSelectionExpr *GE,
+                                            QualType T) {
+    return Visit(GE->getResultExpr(), T);
+  }
+
+  llvm::Constant *VisitChooseExpr(ChooseExpr *CE, QualType T) {
+    return Visit(CE->getChosenSubExpr(), T);
+  }
+
+  llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E, QualType T) {
+    return Visit(E->getInitializer(), T);
+  }
+
+  llvm::Constant *VisitCastExpr(CastExpr *E, QualType destType) {
+    if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
+      CGM.EmitExplicitCastExprType(ECE, Emitter.CGF);
+    Expr *subExpr = E->getSubExpr();
+
+    switch (E->getCastKind()) {
+    case CK_ToUnion: {
+      // GCC cast to union extension
+      assert(E->getType()->isUnionType() &&
+             "Destination type is not union type!");
+
+      auto field = E->getTargetUnionField();
+
+      auto C = Emitter.tryEmitPrivateForMemory(subExpr, field->getType());
+      if (!C) return nullptr;
+
+      auto destTy = ConvertType(destType);
+      if (C->getType() == destTy) return C;
+
+      // Build a struct with the union sub-element as the first member,
+      // and padded to the appropriate size.
+      SmallVector<llvm::Constant*, 2> Elts;
+      SmallVector<llvm::Type*, 2> Types;
+      Elts.push_back(C);
+      Types.push_back(C->getType());
+      unsigned CurSize = CGM.getDataLayout().getTypeAllocSize(C->getType());
+      unsigned TotalSize = CGM.getDataLayout().getTypeAllocSize(destTy);
+
+      assert(CurSize <= TotalSize && "Union size mismatch!");
+      if (unsigned NumPadBytes = TotalSize - CurSize) {
+        llvm::Type *Ty = CGM.Int8Ty;
+        if (NumPadBytes > 1)
+          Ty = llvm::ArrayType::get(Ty, NumPadBytes);
+
+        Elts.push_back(llvm::UndefValue::get(Ty));
+        Types.push_back(Ty);
+      }
+
+      llvm::StructType *STy = llvm::StructType::get(VMContext, Types, false);
+      return llvm::ConstantStruct::get(STy, Elts);
+    }
+
+    case CK_AddressSpaceConversion: {
+      auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
+      if (!C) return nullptr;
+      LangAS destAS = E->getType()->getPointeeType().getAddressSpace();
+      LangAS srcAS = subExpr->getType()->getPointeeType().getAddressSpace();
+      llvm::Type *destTy = ConvertType(E->getType());
+      return CGM.getTargetCodeGenInfo().performAddrSpaceCast(CGM, C, srcAS,
+                                                             destAS, destTy);
+    }
+
+    case CK_LValueToRValue:
+    case CK_AtomicToNonAtomic:
+    case CK_NonAtomicToAtomic:
+    case CK_NoOp:
+    case CK_ConstructorConversion:
+      return Visit(subExpr, destType);
+
+    case CK_IntToOCLSampler:
+      llvm_unreachable("global sampler variables are not generated");
+
+    case CK_Dependent: llvm_unreachable("saw dependent cast!");
+
+    case CK_BuiltinFnToFnPtr:
+      llvm_unreachable("builtin functions are handled elsewhere");
+
+    case CK_ReinterpretMemberPointer:
+    case CK_DerivedToBaseMemberPointer:
+    case CK_BaseToDerivedMemberPointer: {
+      auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
+      if (!C) return nullptr;
+      return CGM.getCXXABI().EmitMemberPointerConversion(E, C);
+    }
+
+    // These will never be supported.
+    case CK_ObjCObjectLValueCast:
+    case CK_ARCProduceObject:
+    case CK_ARCConsumeObject:
+    case CK_ARCReclaimReturnedObject:
+    case CK_ARCExtendBlockObject:
+    case CK_CopyAndAutoreleaseBlockObject:
+      return nullptr;
+
+    // These don't need to be handled here because Evaluate knows how to
+    // evaluate them in the cases where they can be folded.
+    case CK_BitCast:
+    case CK_ToVoid:
+    case CK_Dynamic:
+    case CK_LValueBitCast:
+    case CK_LValueToRValueBitCast:
+    case CK_NullToMemberPointer:
+    case CK_UserDefinedConversion:
+    case CK_CPointerToObjCPointerCast:
+    case CK_BlockPointerToObjCPointerCast:
+    case CK_AnyPointerToBlockPointerCast:
+    case CK_ArrayToPointerDecay:
+    case CK_FunctionToPointerDecay:
+    case CK_BaseToDerived:
+    case CK_DerivedToBase:
+    case CK_UncheckedDerivedToBase:
+    case CK_MemberPointerToBoolean:
+    case CK_VectorSplat:
+    case CK_FloatingRealToComplex:
+    case CK_FloatingComplexToReal:
+    case CK_FloatingComplexToBoolean:
+    case CK_FloatingComplexCast:
+    case CK_FloatingComplexToIntegralComplex:
+    case CK_IntegralRealToComplex:
+    case CK_IntegralComplexToReal:
+    case CK_IntegralComplexToBoolean:
+    case CK_IntegralComplexCast:
+    case CK_IntegralComplexToFloatingComplex:
+    case CK_PointerToIntegral:
+    case CK_PointerToBoolean:
+    case CK_NullToPointer:
+    case CK_IntegralCast:
+    case CK_BooleanToSignedIntegral:
+    case CK_IntegralToPointer:
+    case CK_IntegralToBoolean:
+    case CK_IntegralToFloating:
+    case CK_FloatingToIntegral:
+    case CK_FloatingToBoolean:
+    case CK_FloatingCast:
+    case CK_FixedPointCast:
+    case CK_FixedPointToBoolean:
+    case CK_FixedPointToIntegral:
+    case CK_IntegralToFixedPoint:
+    case CK_ZeroToOCLOpaqueType:
+      return nullptr;
+    }
+    llvm_unreachable("Invalid CastKind");
+  }
+
+  llvm::Constant *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE, QualType T) {
+    // No need for a DefaultInitExprScope: we don't handle 'this' in a
+    // constant expression.
+    return Visit(DIE->getExpr(), T);
+  }
+
+  llvm::Constant *VisitExprWithCleanups(ExprWithCleanups *E, QualType T) {
+    if (!E->cleanupsHaveSideEffects())
+      return Visit(E->getSubExpr(), T);
+    return nullptr;
+  }
+
+  llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
+                                                QualType T) {
+    return Visit(E->GetTemporaryExpr(), T);
+  }
+
+  llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) {
+    auto *CAT = CGM.getContext().getAsConstantArrayType(ILE->getType());
+    assert(CAT && "can't emit array init for non-constant-bound array");
+    unsigned NumInitElements = ILE->getNumInits();
+    unsigned NumElements = CAT->getSize().getZExtValue();
+
+    // Initialising an array requires us to automatically
+    // initialise any elements that have not been initialised explicitly
+    unsigned NumInitableElts = std::min(NumInitElements, NumElements);
+
+    QualType EltType = CAT->getElementType();
+
+    // Initialize remaining array elements.
+    llvm::Constant *fillC = nullptr;
+    if (Expr *filler = ILE->getArrayFiller()) {
+      fillC = Emitter.tryEmitAbstractForMemory(filler, EltType);
+      if (!fillC)
+        return nullptr;
+    }
+
+    // Copy initializer elements.
+    SmallVector<llvm::Constant*, 16> Elts;
+    if (fillC && fillC->isNullValue())
+      Elts.reserve(NumInitableElts + 1);
+    else
+      Elts.reserve(NumElements);
+
+    llvm::Type *CommonElementType = nullptr;
+    for (unsigned i = 0; i < NumInitableElts; ++i) {
+      Expr *Init = ILE->getInit(i);
+      llvm::Constant *C = Emitter.tryEmitPrivateForMemory(Init, EltType);
+      if (!C)
+        return nullptr;
+      if (i == 0)
+        CommonElementType = C->getType();
+      else if (C->getType() != CommonElementType)
+        CommonElementType = nullptr;
+      Elts.push_back(C);
+    }
+
+    llvm::ArrayType *Desired =
+        cast<llvm::ArrayType>(CGM.getTypes().ConvertType(ILE->getType()));
+    return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
+                             fillC);
+  }
+
+  llvm::Constant *EmitRecordInitialization(InitListExpr *ILE, QualType T) {
+    return ConstStructBuilder::BuildStruct(Emitter, ILE, T);
+  }
+
+  llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E,
+                                             QualType T) {
+    return CGM.EmitNullConstant(T);
+  }
+
+  llvm::Constant *VisitInitListExpr(InitListExpr *ILE, QualType T) {
+    if (ILE->isTransparent())
+      return Visit(ILE->getInit(0), T);
+
+    if (ILE->getType()->isArrayType())
+      return EmitArrayInitialization(ILE, T);
+
+    if (ILE->getType()->isRecordType())
+      return EmitRecordInitialization(ILE, T);
+
+    return nullptr;
+  }
+
+  llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E,
+                                                QualType destType) {
+    auto C = Visit(E->getBase(), destType);
+    if (!C)
+      return nullptr;
+
+    ConstantAggregateBuilder Const(CGM);
+    Const.add(C, CharUnits::Zero(), false);
+
+    if (!EmitDesignatedInitUpdater(Emitter, Const, CharUnits::Zero(), destType,
+                                   E->getUpdater()))
+      return nullptr;
+
+    llvm::Type *ValTy = CGM.getTypes().ConvertType(destType);
+    bool HasFlexibleArray = false;
+    if (auto *RT = destType->getAs<RecordType>())
+      HasFlexibleArray = RT->getDecl()->hasFlexibleArrayMember();
+    return Const.build(ValTy, HasFlexibleArray);
+  }
+
+  llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) {
+    if (!E->getConstructor()->isTrivial())
+      return nullptr;
+
+    // FIXME: We should not have to call getBaseElementType here.
+    const RecordType *RT =
+      CGM.getContext().getBaseElementType(Ty)->getAs<RecordType>();
+    const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+
+    // If the class doesn't have a trivial destructor, we can't emit it as a
+    // constant expr.
+    if (!RD->hasTrivialDestructor())
+      return nullptr;
+
+    // Only copy and default constructors can be trivial.
+
+
+    if (E->getNumArgs()) {
+      assert(E->getNumArgs() == 1 && "trivial ctor with > 1 argument");
+      assert(E->getConstructor()->isCopyOrMoveConstructor() &&
+             "trivial ctor has argument but isn't a copy/move ctor");
+
+      Expr *Arg = E->getArg(0);
+      assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) &&
+             "argument to copy ctor is of wrong type");
+
+      return Visit(Arg, Ty);
+    }
+
+    return CGM.EmitNullConstant(Ty);
+  }
+
+  llvm::Constant *VisitStringLiteral(StringLiteral *E, QualType T) {
+    // This is a string literal initializing an array in an initializer.
+    return CGM.GetConstantArrayFromStringLiteral(E);
+  }
+
+  llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E, QualType T) {
+    // This must be an @encode initializing an array in a static initializer.
+    // Don't emit it as the address of the string, emit the string data itself
+    // as an inline array.
+    std::string Str;
+    CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str);
+    const ConstantArrayType *CAT = CGM.getContext().getAsConstantArrayType(T);
+
+    // Resize the string to the right size, adding zeros at the end, or
+    // truncating as needed.
+    Str.resize(CAT->getSize().getZExtValue(), '\0');
+    return llvm::ConstantDataArray::getString(VMContext, Str, false);
+  }
+
+  llvm::Constant *VisitUnaryExtension(const UnaryOperator *E, QualType T) {
+    return Visit(E->getSubExpr(), T);
+  }
+
+  // Utility methods
+  llvm::Type *ConvertType(QualType T) {
+    return CGM.getTypes().ConvertType(T);
+  }
+};
+
+}  // end anonymous namespace.
+
+llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C,
+                                                        AbstractState saved) {
+  Abstract = saved.OldValue;
+
+  assert(saved.OldPlaceholdersSize == PlaceholderAddresses.size() &&
+         "created a placeholder while doing an abstract emission?");
+
+  // No validation necessary for now.
+  // No cleanup to do for now.
+  return C;
+}
+
+llvm::Constant *
+ConstantEmitter::tryEmitAbstractForInitializer(const VarDecl &D) {
+  auto state = pushAbstract();
+  auto C = tryEmitPrivateForVarInit(D);
+  return validateAndPopAbstract(C, state);
+}
+
+llvm::Constant *
+ConstantEmitter::tryEmitAbstract(const Expr *E, QualType destType) {
+  auto state = pushAbstract();
+  auto C = tryEmitPrivate(E, destType);
+  return validateAndPopAbstract(C, state);
+}
+
+llvm::Constant *
+ConstantEmitter::tryEmitAbstract(const APValue &value, QualType destType) {
+  auto state = pushAbstract();
+  auto C = tryEmitPrivate(value, destType);
+  return validateAndPopAbstract(C, state);
+}
+
+llvm::Constant *
+ConstantEmitter::emitAbstract(const Expr *E, QualType destType) {
+  auto state = pushAbstract();
+  auto C = tryEmitPrivate(E, destType);
+  C = validateAndPopAbstract(C, state);
+  if (!C) {
+    CGM.Error(E->getExprLoc(),
+              "internal error: could not emit constant value \"abstractly\"");
+    C = CGM.EmitNullConstant(destType);
+  }
+  return C;
+}
+
+llvm::Constant *
+ConstantEmitter::emitAbstract(SourceLocation loc, const APValue &value,
+                              QualType destType) {
+  auto state = pushAbstract();
+  auto C = tryEmitPrivate(value, destType);
+  C = validateAndPopAbstract(C, state);
+  if (!C) {
+    CGM.Error(loc,
+              "internal error: could not emit constant value \"abstractly\"");
+    C = CGM.EmitNullConstant(destType);
+  }
+  return C;
+}
+
+llvm::Constant *ConstantEmitter::tryEmitForInitializer(const VarDecl &D) {
+  initializeNonAbstract(D.getType().getAddressSpace());
+  return markIfFailed(tryEmitPrivateForVarInit(D));
+}
+
+llvm::Constant *ConstantEmitter::tryEmitForInitializer(const Expr *E,
+                                                       LangAS destAddrSpace,
+                                                       QualType destType) {
+  initializeNonAbstract(destAddrSpace);
+  return markIfFailed(tryEmitPrivateForMemory(E, destType));
+}
+
+llvm::Constant *ConstantEmitter::emitForInitializer(const APValue &value,
+                                                    LangAS destAddrSpace,
+                                                    QualType destType) {
+  initializeNonAbstract(destAddrSpace);
+  auto C = tryEmitPrivateForMemory(value, destType);
+  assert(C && "couldn't emit constant value non-abstractly?");
+  return C;
+}
+
+llvm::GlobalValue *ConstantEmitter::getCurrentAddrPrivate() {
+  assert(!Abstract && "cannot get current address for abstract constant");
+
+
+
+  // Make an obviously ill-formed global that should blow up compilation
+  // if it survives.
+  auto global = new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty, true,
+                                         llvm::GlobalValue::PrivateLinkage,
+                                         /*init*/ nullptr,
+                                         /*name*/ "",
+                                         /*before*/ nullptr,
+                                         llvm::GlobalVariable::NotThreadLocal,
+                                         CGM.getContext().getTargetAddressSpace(DestAddressSpace));
+
+  PlaceholderAddresses.push_back(std::make_pair(nullptr, global));
+
+  return global;
+}
+
+void ConstantEmitter::registerCurrentAddrPrivate(llvm::Constant *signal,
+                                           llvm::GlobalValue *placeholder) {
+  assert(!PlaceholderAddresses.empty());
+  assert(PlaceholderAddresses.back().first == nullptr);
+  assert(PlaceholderAddresses.back().second == placeholder);
+  PlaceholderAddresses.back().first = signal;
+}
+
+namespace {
+  struct ReplacePlaceholders {
+    CodeGenModule &CGM;
+
+    /// The base address of the global.
+    llvm::Constant *Base;
+    llvm::Type *BaseValueTy = nullptr;
+
+    /// The placeholder addresses that were registered during emission.
+    llvm::DenseMap<llvm::Constant*, llvm::GlobalVariable*> PlaceholderAddresses;
+
+    /// The locations of the placeholder signals.
+    llvm::DenseMap<llvm::GlobalVariable*, llvm::Constant*> Locations;
+
+    /// The current index stack.  We use a simple unsigned stack because
+    /// we assume that placeholders will be relatively sparse in the
+    /// initializer, but we cache the index values we find just in case.
+    llvm::SmallVector<unsigned, 8> Indices;
+    llvm::SmallVector<llvm::Constant*, 8> IndexValues;
+
+    ReplacePlaceholders(CodeGenModule &CGM, llvm::Constant *base,
+                        ArrayRef<std::pair<llvm::Constant*,
+                                           llvm::GlobalVariable*>> addresses)
+        : CGM(CGM), Base(base),
+          PlaceholderAddresses(addresses.begin(), addresses.end()) {
+    }
+
+    void replaceInInitializer(llvm::Constant *init) {
+      // Remember the type of the top-most initializer.
+      BaseValueTy = init->getType();
+
+      // Initialize the stack.
+      Indices.push_back(0);
+      IndexValues.push_back(nullptr);
+
+      // Recurse into the initializer.
+      findLocations(init);
+
+      // Check invariants.
+      assert(IndexValues.size() == Indices.size() && "mismatch");
+      assert(Indices.size() == 1 && "didn't pop all indices");
+
+      // Do the replacement; this basically invalidates 'init'.
+      assert(Locations.size() == PlaceholderAddresses.size() &&
+             "missed a placeholder?");
+
+      // We're iterating over a hashtable, so this would be a source of
+      // non-determinism in compiler output *except* that we're just
+      // messing around with llvm::Constant structures, which never itself
+      // does anything that should be visible in compiler output.
+      for (auto &entry : Locations) {
+        assert(entry.first->getParent() == nullptr && "not a placeholder!");
+        entry.first->replaceAllUsesWith(entry.second);
+        entry.first->eraseFromParent();
+      }
+    }
+
+  private:
+    void findLocations(llvm::Constant *init) {
+      // Recurse into aggregates.
+      if (auto agg = dyn_cast<llvm::ConstantAggregate>(init)) {
+        for (unsigned i = 0, e = agg->getNumOperands(); i != e; ++i) {
+          Indices.push_back(i);
+          IndexValues.push_back(nullptr);
+
+          findLocations(agg->getOperand(i));
+
+          IndexValues.pop_back();
+          Indices.pop_back();
+        }
+        return;
+      }
+
+      // Otherwise, check for registered constants.
+      while (true) {
+        auto it = PlaceholderAddresses.find(init);
+        if (it != PlaceholderAddresses.end()) {
+          setLocation(it->second);
+          break;
+        }
+
+        // Look through bitcasts or other expressions.
+        if (auto expr = dyn_cast<llvm::ConstantExpr>(init)) {
+          init = expr->getOperand(0);
+        } else {
+          break;
+        }
+      }
+    }
+
+    void setLocation(llvm::GlobalVariable *placeholder) {
+      assert(Locations.find(placeholder) == Locations.end() &&
+             "already found location for placeholder!");
+
+      // Lazily fill in IndexValues with the values from Indices.
+      // We do this in reverse because we should always have a strict
+      // prefix of indices from the start.
+      assert(Indices.size() == IndexValues.size());
+      for (size_t i = Indices.size() - 1; i != size_t(-1); --i) {
+        if (IndexValues[i]) {
+#ifndef NDEBUG
+          for (size_t j = 0; j != i + 1; ++j) {
+            assert(IndexValues[j] &&
+                   isa<llvm::ConstantInt>(IndexValues[j]) &&
+                   cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue()
+                     == Indices[j]);
+          }
+#endif
+          break;
+        }
+
+        IndexValues[i] = llvm::ConstantInt::get(CGM.Int32Ty, Indices[i]);
+      }
+
+      // Form a GEP and then bitcast to the placeholder type so that the
+      // replacement will succeed.
+      llvm::Constant *location =
+        llvm::ConstantExpr::getInBoundsGetElementPtr(BaseValueTy,
+                                                     Base, IndexValues);
+      location = llvm::ConstantExpr::getBitCast(location,
+                                                placeholder->getType());
+
+      Locations.insert({placeholder, location});
+    }
+  };
+}
+
+void ConstantEmitter::finalize(llvm::GlobalVariable *global) {
+  assert(InitializedNonAbstract &&
+         "finalizing emitter that was used for abstract emission?");
+  assert(!Finalized && "finalizing emitter multiple times");
+  assert(global->getInitializer());
+
+  // Note that we might also be Failed.
+  Finalized = true;
+
+  if (!PlaceholderAddresses.empty()) {
+    ReplacePlaceholders(CGM, global, PlaceholderAddresses)
+      .replaceInInitializer(global->getInitializer());
+    PlaceholderAddresses.clear(); // satisfy
+  }
+}
+
+ConstantEmitter::~ConstantEmitter() {
+  assert((!InitializedNonAbstract || Finalized || Failed) &&
+         "not finalized after being initialized for non-abstract emission");
+  assert(PlaceholderAddresses.empty() && "unhandled placeholders");
+}
+
+static QualType getNonMemoryType(CodeGenModule &CGM, QualType type) {
+  if (auto AT = type->getAs<AtomicType>()) {
+    return CGM.getContext().getQualifiedType(AT->getValueType(),
+                                             type.getQualifiers());
+  }
+  return type;
+}
+
+llvm::Constant *ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &D) {
+  // Make a quick check if variable can be default NULL initialized
+  // and avoid going through rest of code which may do, for c++11,
+  // initialization of memory to all NULLs.
+  if (!D.hasLocalStorage()) {
+    QualType Ty = CGM.getContext().getBaseElementType(D.getType());
+    if (Ty->isRecordType())
+      if (const CXXConstructExpr *E =
+          dyn_cast_or_null<CXXConstructExpr>(D.getInit())) {
+        const CXXConstructorDecl *CD = E->getConstructor();
+        if (CD->isTrivial() && CD->isDefaultConstructor())
+          return CGM.EmitNullConstant(D.getType());
+      }
+    InConstantContext = true;
+  }
+
+  QualType destType = D.getType();
+
+  // Try to emit the initializer.  Note that this can allow some things that
+  // are not allowed by tryEmitPrivateForMemory alone.
+  if (auto value = D.evaluateValue()) {
+    return tryEmitPrivateForMemory(*value, destType);
+  }
+
+  // FIXME: Implement C++11 [basic.start.init]p2: if the initializer of a
+  // reference is a constant expression, and the reference binds to a temporary,
+  // then constant initialization is performed. ConstExprEmitter will
+  // incorrectly emit a prvalue constant in this case, and the calling code
+  // interprets that as the (pointer) value of the reference, rather than the
+  // desired value of the referee.
+  if (destType->isReferenceType())
+    return nullptr;
+
+  const Expr *E = D.getInit();
+  assert(E && "No initializer to emit");
+
+  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
+  auto C =
+    ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), nonMemoryDestType);
+  return (C ? emitForMemory(C, destType) : nullptr);
+}
+
+llvm::Constant *
+ConstantEmitter::tryEmitAbstractForMemory(const Expr *E, QualType destType) {
+  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
+  auto C = tryEmitAbstract(E, nonMemoryDestType);
+  return (C ? emitForMemory(C, destType) : nullptr);
+}
+
+llvm::Constant *
+ConstantEmitter::tryEmitAbstractForMemory(const APValue &value,
+                                          QualType destType) {
+  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
+  auto C = tryEmitAbstract(value, nonMemoryDestType);
+  return (C ? emitForMemory(C, destType) : nullptr);
+}
+
+llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const Expr *E,
+                                                         QualType destType) {
+  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
+  llvm::Constant *C = tryEmitPrivate(E, nonMemoryDestType);
+  return (C ? emitForMemory(C, destType) : nullptr);
+}
+
+llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const APValue &value,
+                                                         QualType destType) {
+  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
+  auto C = tryEmitPrivate(value, nonMemoryDestType);
+  return (C ? emitForMemory(C, destType) : nullptr);
+}
+
+llvm::Constant *ConstantEmitter::emitForMemory(CodeGenModule &CGM,
+                                               llvm::Constant *C,
+                                               QualType destType) {
+  // For an _Atomic-qualified constant, we may need to add tail padding.
+  if (auto AT = destType->getAs<AtomicType>()) {
+    QualType destValueType = AT->getValueType();
+    C = emitForMemory(CGM, C, destValueType);
+
+    uint64_t innerSize = CGM.getContext().getTypeSize(destValueType);
+    uint64_t outerSize = CGM.getContext().getTypeSize(destType);
+    if (innerSize == outerSize)
+      return C;
+
+    assert(innerSize < outerSize && "emitted over-large constant for atomic");
+    llvm::Constant *elts[] = {
+      C,
+      llvm::ConstantAggregateZero::get(
+          llvm::ArrayType::get(CGM.Int8Ty, (outerSize - innerSize) / 8))
+    };
+    return llvm::ConstantStruct::getAnon(elts);
+  }
+
+  // Zero-extend bool.
+  if (C->getType()->isIntegerTy(1)) {
+    llvm::Type *boolTy = CGM.getTypes().ConvertTypeForMem(destType);
+    return llvm::ConstantExpr::getZExt(C, boolTy);
+  }
+
+  return C;
+}
+
+llvm::Constant *ConstantEmitter::tryEmitPrivate(const Expr *E,
+                                                QualType destType) {
+  Expr::EvalResult Result;
+
+  bool Success = false;
+
+  if (destType->isReferenceType())
+    Success = E->EvaluateAsLValue(Result, CGM.getContext());
+  else
+    Success = E->EvaluateAsRValue(Result, CGM.getContext(), InConstantContext);
+
+  llvm::Constant *C;
+  if (Success && !Result.HasSideEffects)
+    C = tryEmitPrivate(Result.Val, destType);
+  else
+    C = ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), destType);
+
+  return C;
+}
+
+llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) {
+  return getTargetCodeGenInfo().getNullPointer(*this, T, QT);
+}
+
+namespace {
+/// A struct which can be used to peephole certain kinds of finalization
+/// that normally happen during l-value emission.
+struct ConstantLValue {
+  llvm::Constant *Value;
+  bool HasOffsetApplied;
+
+  /*implicit*/ ConstantLValue(llvm::Constant *value,
+                              bool hasOffsetApplied = false)
+    : Value(value), HasOffsetApplied(false) {}
+
+  /*implicit*/ ConstantLValue(ConstantAddress address)
+    : ConstantLValue(address.getPointer()) {}
+};
+
+/// A helper class for emitting constant l-values.
+class ConstantLValueEmitter : public ConstStmtVisitor<ConstantLValueEmitter,
+                                                      ConstantLValue> {
+  CodeGenModule &CGM;
+  ConstantEmitter &Emitter;
+  const APValue &Value;
+  QualType DestType;
+
+  // Befriend StmtVisitorBase so that we don't have to expose Visit*.
+  friend StmtVisitorBase;
+
+public:
+  ConstantLValueEmitter(ConstantEmitter &emitter, const APValue &value,
+                        QualType destType)
+    : CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType) {}
+
+  llvm::Constant *tryEmit();
+
+private:
+  llvm::Constant *tryEmitAbsolute(llvm::Type *destTy);
+  ConstantLValue tryEmitBase(const APValue::LValueBase &base);
+
+  ConstantLValue VisitStmt(const Stmt *S) { return nullptr; }
+  ConstantLValue VisitConstantExpr(const ConstantExpr *E);
+  ConstantLValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
+  ConstantLValue VisitStringLiteral(const StringLiteral *E);
+  ConstantLValue VisitObjCBoxedExpr(const ObjCBoxedExpr *E);
+  ConstantLValue VisitObjCEncodeExpr(const ObjCEncodeExpr *E);
+  ConstantLValue VisitObjCStringLiteral(const ObjCStringLiteral *E);
+  ConstantLValue VisitPredefinedExpr(const PredefinedExpr *E);
+  ConstantLValue VisitAddrLabelExpr(const AddrLabelExpr *E);
+  ConstantLValue VisitCallExpr(const CallExpr *E);
+  ConstantLValue VisitBlockExpr(const BlockExpr *E);
+  ConstantLValue VisitCXXTypeidExpr(const CXXTypeidExpr *E);
+  ConstantLValue VisitCXXUuidofExpr(const CXXUuidofExpr *E);
+  ConstantLValue VisitMaterializeTemporaryExpr(
+                                         const MaterializeTemporaryExpr *E);
+
+  bool hasNonZeroOffset() const {
+    return !Value.getLValueOffset().isZero();
+  }
+
+  /// Return the value offset.
+  llvm::Constant *getOffset() {
+    return llvm::ConstantInt::get(CGM.Int64Ty,
+                                  Value.getLValueOffset().getQuantity());
+  }
+
+  /// Apply the value offset to the given constant.
+  llvm::Constant *applyOffset(llvm::Constant *C) {
+    if (!hasNonZeroOffset())
+      return C;
+
+    llvm::Type *origPtrTy = C->getType();
+    unsigned AS = origPtrTy->getPointerAddressSpace();
+    llvm::Type *charPtrTy = CGM.Int8Ty->getPointerTo(AS);
+    C = llvm::ConstantExpr::getBitCast(C, charPtrTy);
+    C = llvm::ConstantExpr::getGetElementPtr(CGM.Int8Ty, C, getOffset());
+    C = llvm::ConstantExpr::getPointerCast(C, origPtrTy);
+    return C;
+  }
+};
+
+}
+
+llvm::Constant *ConstantLValueEmitter::tryEmit() {
+  const APValue::LValueBase &base = Value.getLValueBase();
+
+  // The destination type should be a pointer or reference
+  // type, but it might also be a cast thereof.
+  //
+  // FIXME: the chain of casts required should be reflected in the APValue.
+  // We need this in order to correctly handle things like a ptrtoint of a
+  // non-zero null pointer and addrspace casts that aren't trivially
+  // represented in LLVM IR.
+  auto destTy = CGM.getTypes().ConvertTypeForMem(DestType);
+  assert(isa<llvm::IntegerType>(destTy) || isa<llvm::PointerType>(destTy));
+
+  // If there's no base at all, this is a null or absolute pointer,
+  // possibly cast back to an integer type.
+  if (!base) {
+    return tryEmitAbsolute(destTy);
+  }
+
+  // Otherwise, try to emit the base.
+  ConstantLValue result = tryEmitBase(base);
+
+  // If that failed, we're done.
+  llvm::Constant *value = result.Value;
+  if (!value) return nullptr;
+
+  // Apply the offset if necessary and not already done.
+  if (!result.HasOffsetApplied) {
+    value = applyOffset(value);
+  }
+
+  // Convert to the appropriate type; this could be an lvalue for
+  // an integer.  FIXME: performAddrSpaceCast
+  if (isa<llvm::PointerType>(destTy))
+    return llvm::ConstantExpr::getPointerCast(value, destTy);
+
+  return llvm::ConstantExpr::getPtrToInt(value, destTy);
+}
+
+/// Try to emit an absolute l-value, such as a null pointer or an integer
+/// bitcast to pointer type.
+llvm::Constant *
+ConstantLValueEmitter::tryEmitAbsolute(llvm::Type *destTy) {
+  // If we're producing a pointer, this is easy.
+  auto destPtrTy = cast<llvm::PointerType>(destTy);
+  if (Value.isNullPointer()) {
+    // FIXME: integer offsets from non-zero null pointers.
+    return CGM.getNullPointer(destPtrTy, DestType);
+  }
+
+  // Convert the integer to a pointer-sized integer before converting it
+  // to a pointer.
+  // FIXME: signedness depends on the original integer type.
+  auto intptrTy = CGM.getDataLayout().getIntPtrType(destPtrTy);
+  llvm::Constant *C;
+  C = llvm::ConstantExpr::getIntegerCast(getOffset(), intptrTy,
+                                         /*isSigned*/ false);
+  C = llvm::ConstantExpr::getIntToPtr(C, destPtrTy);
+  return C;
+}
+
+ConstantLValue
+ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) {
+  // Handle values.
+  if (const ValueDecl *D = base.dyn_cast<const ValueDecl*>()) {
+    if (D->hasAttr<WeakRefAttr>())
+      return CGM.GetWeakRefReference(D).getPointer();
+
+    if (auto FD = dyn_cast<FunctionDecl>(D))
+      return CGM.GetAddrOfFunction(FD);
+
+    if (auto VD = dyn_cast<VarDecl>(D)) {
+      // We can never refer to a variable with local storage.
+      if (!VD->hasLocalStorage()) {
+        if (VD->isFileVarDecl() || VD->hasExternalStorage())
+          return CGM.GetAddrOfGlobalVar(VD);
+
+        if (VD->isLocalVarDecl()) {
+          return CGM.getOrCreateStaticVarDecl(
+              *VD, CGM.getLLVMLinkageVarDefinition(VD, /*IsConstant=*/false));
+        }
+      }
+    }
+
+    return nullptr;
+  }
+
+  // Handle typeid(T).
+  if (TypeInfoLValue TI = base.dyn_cast<TypeInfoLValue>()) {
+    llvm::Type *StdTypeInfoPtrTy =
+        CGM.getTypes().ConvertType(base.getTypeInfoType())->getPointerTo();
+    llvm::Constant *TypeInfo =
+        CGM.GetAddrOfRTTIDescriptor(QualType(TI.getType(), 0));
+    if (TypeInfo->getType() != StdTypeInfoPtrTy)
+      TypeInfo = llvm::ConstantExpr::getBitCast(TypeInfo, StdTypeInfoPtrTy);
+    return TypeInfo;
+  }
+
+  // Otherwise, it must be an expression.
+  return Visit(base.get<const Expr*>());
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitConstantExpr(const ConstantExpr *E) {
+  return Visit(E->getSubExpr());
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
+  return tryEmitGlobalCompoundLiteral(CGM, Emitter.CGF, E);
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitStringLiteral(const StringLiteral *E) {
+  return CGM.GetAddrOfConstantStringFromLiteral(E);
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
+  return CGM.GetAddrOfConstantStringFromObjCEncode(E);
+}
+
+static ConstantLValue emitConstantObjCStringLiteral(const StringLiteral *S,
+                                                    QualType T,
+                                                    CodeGenModule &CGM) {
+  auto C = CGM.getObjCRuntime().GenerateConstantString(S);
+  return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(T));
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) {
+  return emitConstantObjCStringLiteral(E->getString(), E->getType(), CGM);
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
+  assert(E->isExpressibleAsConstantInitializer() &&
+         "this boxed expression can't be emitted as a compile-time constant");
+  auto *SL = cast<StringLiteral>(E->getSubExpr()->IgnoreParenCasts());
+  return emitConstantObjCStringLiteral(SL, E->getType(), CGM);
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitPredefinedExpr(const PredefinedExpr *E) {
+  return CGM.GetAddrOfConstantStringFromLiteral(E->getFunctionName());
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitAddrLabelExpr(const AddrLabelExpr *E) {
+  assert(Emitter.CGF && "Invalid address of label expression outside function");
+  llvm::Constant *Ptr = Emitter.CGF->GetAddrOfLabel(E->getLabel());
+  Ptr = llvm::ConstantExpr::getBitCast(Ptr,
+                                   CGM.getTypes().ConvertType(E->getType()));
+  return Ptr;
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitCallExpr(const CallExpr *E) {
+  unsigned builtin = E->getBuiltinCallee();
+  if (builtin != Builtin::BI__builtin___CFStringMakeConstantString &&
+      builtin != Builtin::BI__builtin___NSStringMakeConstantString)
+    return nullptr;
+
+  auto literal = cast<StringLiteral>(E->getArg(0)->IgnoreParenCasts());
+  if (builtin == Builtin::BI__builtin___NSStringMakeConstantString) {
+    return CGM.getObjCRuntime().GenerateConstantString(literal);
+  } else {
+    // FIXME: need to deal with UCN conversion issues.
+    return CGM.GetAddrOfConstantCFString(literal);
+  }
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitBlockExpr(const BlockExpr *E) {
+  StringRef functionName;
+  if (auto CGF = Emitter.CGF)
+    functionName = CGF->CurFn->getName();
+  else
+    functionName = "global";
+
+  return CGM.GetAddrOfGlobalBlock(E, functionName);
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
+  QualType T;
+  if (E->isTypeOperand())
+    T = E->getTypeOperand(CGM.getContext());
+  else
+    T = E->getExprOperand()->getType();
+  return CGM.GetAddrOfRTTIDescriptor(T);
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
+  return CGM.GetAddrOfUuidDescriptor(E);
+}
+
+ConstantLValue
+ConstantLValueEmitter::VisitMaterializeTemporaryExpr(
+                                            const MaterializeTemporaryExpr *E) {
+  assert(E->getStorageDuration() == SD_Static);
+  SmallVector<const Expr *, 2> CommaLHSs;
+  SmallVector<SubobjectAdjustment, 2> Adjustments;
+  const Expr *Inner = E->GetTemporaryExpr()
+      ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
+  return CGM.GetAddrOfGlobalTemporary(E, Inner);
+}
+
+llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
+                                                QualType DestType) {
+  switch (Value.getKind()) {
+  case APValue::None:
+  case APValue::Indeterminate:
+    // Out-of-lifetime and indeterminate values can be modeled as 'undef'.
+    return llvm::UndefValue::get(CGM.getTypes().ConvertType(DestType));
+  case APValue::LValue:
+    return ConstantLValueEmitter(*this, Value, DestType).tryEmit();
+  case APValue::Int:
+    return llvm::ConstantInt::get(CGM.getLLVMContext(), Value.getInt());
+  case APValue::FixedPoint:
+    return llvm::ConstantInt::get(CGM.getLLVMContext(),
+                                  Value.getFixedPoint().getValue());
+  case APValue::ComplexInt: {
+    llvm::Constant *Complex[2];
+
+    Complex[0] = llvm::ConstantInt::get(CGM.getLLVMContext(),
+                                        Value.getComplexIntReal());
+    Complex[1] = llvm::ConstantInt::get(CGM.getLLVMContext(),
+                                        Value.getComplexIntImag());
+
+    // FIXME: the target may want to specify that this is packed.
+    llvm::StructType *STy =
+        llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
+    return llvm::ConstantStruct::get(STy, Complex);
+  }
+  case APValue::Float: {
+    const llvm::APFloat &Init = Value.getFloat();
+    if (&Init.getSemantics() == &llvm::APFloat::IEEEhalf() &&
+        !CGM.getContext().getLangOpts().NativeHalfType &&
+        CGM.getContext().getTargetInfo().useFP16ConversionIntrinsics())
+      return llvm::ConstantInt::get(CGM.getLLVMContext(),
+                                    Init.bitcastToAPInt());
+    else
+      return llvm::ConstantFP::get(CGM.getLLVMContext(), Init);
+  }
+  case APValue::ComplexFloat: {
+    llvm::Constant *Complex[2];
+
+    Complex[0] = llvm::ConstantFP::get(CGM.getLLVMContext(),
+                                       Value.getComplexFloatReal());
+    Complex[1] = llvm::ConstantFP::get(CGM.getLLVMContext(),
+                                       Value.getComplexFloatImag());
+
+    // FIXME: the target may want to specify that this is packed.
+    llvm::StructType *STy =
+        llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
+    return llvm::ConstantStruct::get(STy, Complex);
+  }
+  case APValue::Vector: {
+    unsigned NumElts = Value.getVectorLength();
+    SmallVector<llvm::Constant *, 4> Inits(NumElts);
+
+    for (unsigned I = 0; I != NumElts; ++I) {
+      const APValue &Elt = Value.getVectorElt(I);
+      if (Elt.isInt())
+        Inits[I] = llvm::ConstantInt::get(CGM.getLLVMContext(), Elt.getInt());
+      else if (Elt.isFloat())
+        Inits[I] = llvm::ConstantFP::get(CGM.getLLVMContext(), Elt.getFloat());
+      else
+        llvm_unreachable("unsupported vector element type");
+    }
+    return llvm::ConstantVector::get(Inits);
+  }
+  case APValue::AddrLabelDiff: {
+    const AddrLabelExpr *LHSExpr = Value.getAddrLabelDiffLHS();
+    const AddrLabelExpr *RHSExpr = Value.getAddrLabelDiffRHS();
+    llvm::Constant *LHS = tryEmitPrivate(LHSExpr, LHSExpr->getType());
+    llvm::Constant *RHS = tryEmitPrivate(RHSExpr, RHSExpr->getType());
+    if (!LHS || !RHS) return nullptr;
+
+    // Compute difference
+    llvm::Type *ResultType = CGM.getTypes().ConvertType(DestType);
+    LHS = llvm::ConstantExpr::getPtrToInt(LHS, CGM.IntPtrTy);
+    RHS = llvm::ConstantExpr::getPtrToInt(RHS, CGM.IntPtrTy);
+    llvm::Constant *AddrLabelDiff = llvm::ConstantExpr::getSub(LHS, RHS);
+
+    // LLVM is a bit sensitive about the exact format of the
+    // address-of-label difference; make sure to truncate after
+    // the subtraction.
+    return llvm::ConstantExpr::getTruncOrBitCast(AddrLabelDiff, ResultType);
+  }
+  case APValue::Struct:
+  case APValue::Union:
+    return ConstStructBuilder::BuildStruct(*this, Value, DestType);
+  case APValue::Array: {
+    const ConstantArrayType *CAT =
+        CGM.getContext().getAsConstantArrayType(DestType);
+    unsigned NumElements = Value.getArraySize();
+    unsigned NumInitElts = Value.getArrayInitializedElts();
+
+    // Emit array filler, if there is one.
+    llvm::Constant *Filler = nullptr;
+    if (Value.hasArrayFiller()) {
+      Filler = tryEmitAbstractForMemory(Value.getArrayFiller(),
+                                        CAT->getElementType());
+      if (!Filler)
+        return nullptr;
+    }
+
+    // Emit initializer elements.
+    SmallVector<llvm::Constant*, 16> Elts;
+    if (Filler && Filler->isNullValue())
+      Elts.reserve(NumInitElts + 1);
+    else
+      Elts.reserve(NumElements);
+
+    llvm::Type *CommonElementType = nullptr;
+    for (unsigned I = 0; I < NumInitElts; ++I) {
+      llvm::Constant *C = tryEmitPrivateForMemory(
+          Value.getArrayInitializedElt(I), CAT->getElementType());
+      if (!C) return nullptr;
+
+      if (I == 0)
+        CommonElementType = C->getType();
+      else if (C->getType() != CommonElementType)
+        CommonElementType = nullptr;
+      Elts.push_back(C);
+    }
+
+    // This means that the array type is probably "IncompleteType" or some
+    // type that is not ConstantArray.
+    if (CAT == nullptr && CommonElementType == nullptr && !NumInitElts) {
+      const ArrayType *AT = CGM.getContext().getAsArrayType(DestType);
+      CommonElementType = CGM.getTypes().ConvertType(AT->getElementType());
+      llvm::ArrayType *AType = llvm::ArrayType::get(CommonElementType,
+                                                    NumElements);
+      return llvm::ConstantAggregateZero::get(AType);
+    }
+
+    llvm::ArrayType *Desired =
+        cast<llvm::ArrayType>(CGM.getTypes().ConvertType(DestType));
+    return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
+                             Filler);
+  }
+  case APValue::MemberPointer:
+    return CGM.getCXXABI().EmitMemberPointer(Value, DestType);
+  }
+  llvm_unreachable("Unknown APValue kind");
+}
+
+llvm::GlobalVariable *CodeGenModule::getAddrOfConstantCompoundLiteralIfEmitted(
+    const CompoundLiteralExpr *E) {
+  return EmittedCompoundLiterals.lookup(E);
+}
+
+void CodeGenModule::setAddrOfConstantCompoundLiteral(
+    const CompoundLiteralExpr *CLE, llvm::GlobalVariable *GV) {
+  bool Ok = EmittedCompoundLiterals.insert(std::make_pair(CLE, GV)).second;
+  (void)Ok;
+  assert(Ok && "CLE has already been emitted!");
+}
+
+ConstantAddress
+CodeGenModule::GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr *E) {
+  assert(E->isFileScope() && "not a file-scope compound literal expr");
+  return tryEmitGlobalCompoundLiteral(*this, nullptr, E);
+}
+
+llvm::Constant *
+CodeGenModule::getMemberPointerConstant(const UnaryOperator *uo) {
+  // Member pointer constants always have a very particular form.
+  const MemberPointerType *type = cast<MemberPointerType>(uo->getType());
+  const ValueDecl *decl = cast<DeclRefExpr>(uo->getSubExpr())->getDecl();
+
+  // A member function pointer.
+  if (const CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(decl))
+    return getCXXABI().EmitMemberFunctionPointer(method);
+
+  // Otherwise, a member data pointer.
+  uint64_t fieldOffset = getContext().getFieldOffset(decl);
+  CharUnits chars = getContext().toCharUnitsFromBits((int64_t) fieldOffset);
+  return getCXXABI().EmitMemberDataPointer(type, chars);
+}
+
+static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
+                                               llvm::Type *baseType,
+                                               const CXXRecordDecl *base);
+
+static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
+                                        const RecordDecl *record,
+                                        bool asCompleteObject) {
+  const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record);
+  llvm::StructType *structure =
+    (asCompleteObject ? layout.getLLVMType()
+                      : layout.getBaseSubobjectLLVMType());
+
+  unsigned numElements = structure->getNumElements();
+  std::vector<llvm::Constant *> elements(numElements);
+
+  auto CXXR = dyn_cast<CXXRecordDecl>(record);
+  // Fill in all the bases.
+  if (CXXR) {
+    for (const auto &I : CXXR->bases()) {
+      if (I.isVirtual()) {
+        // Ignore virtual bases; if we're laying out for a complete
+        // object, we'll lay these out later.
+        continue;
+      }
+
+      const CXXRecordDecl *base =
+        cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
+
+      // Ignore empty bases.
+      if (base->isEmpty() ||
+          CGM.getContext().getASTRecordLayout(base).getNonVirtualSize()
+              .isZero())
+        continue;
+
+      unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
+      llvm::Type *baseType = structure->getElementType(fieldIndex);
+      elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
+    }
+  }
+
+  // Fill in all the fields.
+  for (const auto *Field : record->fields()) {
+    // Fill in non-bitfields. (Bitfields always use a zero pattern, which we
+    // will fill in later.)
+    if (!Field->isBitField() && !Field->isZeroSize(CGM.getContext())) {
+      unsigned fieldIndex = layout.getLLVMFieldNo(Field);
+      elements[fieldIndex] = CGM.EmitNullConstant(Field->getType());
+    }
+
+    // For unions, stop after the first named field.
+    if (record->isUnion()) {
+      if (Field->getIdentifier())
+        break;
+      if (const auto *FieldRD = Field->getType()->getAsRecordDecl())
+        if (FieldRD->findFirstNamedDataMember())
+          break;
+    }
+  }
+
+  // Fill in the virtual bases, if we're working with the complete object.
+  if (CXXR && asCompleteObject) {
+    for (const auto &I : CXXR->vbases()) {
+      const CXXRecordDecl *base =
+        cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
+
+      // Ignore empty bases.
+      if (base->isEmpty())
+        continue;
+
+      unsigned fieldIndex = layout.getVirtualBaseIndex(base);
+
+      // We might have already laid this field out.
+      if (elements[fieldIndex]) continue;
+
+      llvm::Type *baseType = structure->getElementType(fieldIndex);
+      elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
+    }
+  }
+
+  // Now go through all other fields and zero them out.
+  for (unsigned i = 0; i != numElements; ++i) {
+    if (!elements[i])
+      elements[i] = llvm::Constant::getNullValue(structure->getElementType(i));
+  }
+
+  return llvm::ConstantStruct::get(structure, elements);
+}
+
+/// Emit the null constant for a base subobject.
+static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
+                                               llvm::Type *baseType,
+                                               const CXXRecordDecl *base) {
+  const CGRecordLayout &baseLayout = CGM.getTypes().getCGRecordLayout(base);
+
+  // Just zero out bases that don't have any pointer to data members.
+  if (baseLayout.isZeroInitializableAsBase())
+    return llvm::Constant::getNullValue(baseType);
+
+  // Otherwise, we can just use its null constant.
+  return EmitNullConstant(CGM, base, /*asCompleteObject=*/false);
+}
+
+llvm::Constant *ConstantEmitter::emitNullForMemory(CodeGenModule &CGM,
+                                                   QualType T) {
+  return emitForMemory(CGM, CGM.EmitNullConstant(T), T);
+}
+
+llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
+  if (T->getAs<PointerType>())
+    return getNullPointer(
+        cast<llvm::PointerType>(getTypes().ConvertTypeForMem(T)), T);
+
+  if (getTypes().isZeroInitializable(T))
+    return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
+
+  if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) {
+    llvm::ArrayType *ATy =
+      cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T));
+
+    QualType ElementTy = CAT->getElementType();
+
+    llvm::Constant *Element =
+      ConstantEmitter::emitNullForMemory(*this, ElementTy);
+    unsigned NumElements = CAT->getSize().getZExtValue();
+    SmallVector<llvm::Constant *, 8> Array(NumElements, Element);
+    return llvm::ConstantArray::get(ATy, Array);
+  }
+
+  if (const RecordType *RT = T->getAs<RecordType>())
+    return ::EmitNullConstant(*this, RT->getDecl(), /*complete object*/ true);
+
+  assert(T->isMemberDataPointerType() &&
+         "Should only see pointers to data members here!");
+
+  return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>());
+}
+
+llvm::Constant *
+CodeGenModule::EmitNullConstantForBase(const CXXRecordDecl *Record) {
+  return ::EmitNullConstant(*this, Record, false);
+}