/build/source/clang/lib/CodeGen/CGExprConstant.cpp

Bug Summary

File:	build/source/clang/lib/CodeGen/CGExprConstant.cpp
Warning:	line 722, column 11 Called C++ object pointer is null
Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name CGExprConstant.cpp -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -relaxed-aliasing -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/source/build-llvm -resource-dir /usr/lib/llvm-17/lib/clang/17 -D _DEBUG -D _GLIBCXX_ASSERTIONS -D _GNU_SOURCE -D _LIBCPP_ENABLE_ASSERTIONS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I tools/clang/lib/CodeGen -I /build/source/clang/lib/CodeGen -I /build/source/clang/include -I tools/clang/include -I include -I /build/source/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-17/lib/clang/17/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/source/build-llvm=build-llvm -fmacro-prefix-map=/build/source/= -fcoverage-prefix-map=/build/source/build-llvm=build-llvm -fcoverage-prefix-map=/build/source/= -source-date-epoch 1679915782 -O3 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -Wno-misleading-indentation -std=c++17 -fdeprecated-macro -fdebug-compilation-dir=/build/source/build-llvm -fdebug-prefix-map=/build/source/build-llvm=build-llvm -fdebug-prefix-map=/build/source/= -fdebug-prefix-map=/build/source/build-llvm=build-llvm -fdebug-prefix-map=/build/source/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2023-03-27-130437-16335-1 -x c++ /build/source/clang/lib/CodeGen/CGExprConstant.cpp
1//===--- CGExprConstant.cpp - Emit LLVM Code from Constant Expressions ----===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This contains code to emit Constant Expr nodes as LLVM code.
10//
11//===----------------------------------------------------------------------===//

13#include "CGCXXABI.h"
14#include "CGObjCRuntime.h"
15#include "CGRecordLayout.h"
16#include "CodeGenFunction.h"
17#include "CodeGenModule.h"
18#include "ConstantEmitter.h"
19#include "TargetInfo.h"
20#include "clang/AST/APValue.h"
21#include "clang/AST/ASTContext.h"
22#include "clang/AST/Attr.h"
23#include "clang/AST/RecordLayout.h"
24#include "clang/AST/StmtVisitor.h"
25#include "clang/Basic/Builtins.h"
26#include "llvm/ADT/STLExtras.h"
27#include "llvm/ADT/Sequence.h"
28#include "llvm/IR/Constants.h"
29#include "llvm/IR/DataLayout.h"
30#include "llvm/IR/Function.h"
31#include "llvm/IR/GlobalVariable.h"
32#include <optional>
33using namespace clang;
34using namespace CodeGen;

36//===----------------------------------------------------------------------===//
37//                            ConstantAggregateBuilder
38//===----------------------------------------------------------------------===//

40namespace {
41class ConstExprEmitter;

43struct ConstantAggregateBuilderUtils {
CodeGenModule &CGM;

ConstantAggregateBuilderUtils(CodeGenModule &CGM) : CGM(CGM) {}

CharUnits getAlignment(const llvm::Constant *C) const {
  return CharUnits::fromQuantity(
      CGM.getDataLayout().getABITypeAlign(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.CharTy;
  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.CharTy, ZeroSize.getQuantity());
  return llvm::ConstantAggregateZero::get(Ty);
}
72};

74/// Incremental builder for an llvm::Constant* holding a struct or array
75/// constant.
76class 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);
std::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);

107public:
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);
}
134};

136template<typename Container, typename Range = std::initializer_list<
                               typename Container::value_type>>
138static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
assert(BeginOff <= EndOff && "invalid replacement range")(static_cast <bool> (BeginOff <= EndOff && "invalid replacement range"
) ? void (0) : __assert_fail ("BeginOff <= EndOff && \"invalid replacement range\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 139, __extension__ __PRETTY_FUNCTION__
));
llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
141}

143bool 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.
std::optional<size_t> FirstElemToReplace = splitAt(Offset);
if (!FirstElemToReplace)
  return false;

CharUnits CSize = getSize(C);
std::optional<size_t> LastElemToReplace = splitAt(Offset + CSize);
if (!LastElemToReplace)
  return false;

assert((FirstElemToReplace == LastElemToReplace || AllowOverwrite) &&(static_cast <bool> ((FirstElemToReplace == LastElemToReplace
 || AllowOverwrite) && "unexpectedly overwriting field"
) ? void (0) : __assert_fail ("(FirstElemToReplace == LastElemToReplace || AllowOverwrite) && \"unexpectedly overwriting field\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 172, __extension__ __PRETTY_FUNCTION__
))
       "unexpectedly overwriting field")(static_cast <bool> ((FirstElemToReplace == LastElemToReplace
 || AllowOverwrite) && "unexpectedly overwriting field"
) ? void (0) : __assert_fail ("(FirstElemToReplace == LastElemToReplace || AllowOverwrite) && \"unexpectedly overwriting field\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 172, __extension__ __PRETTY_FUNCTION__
));

replace(Elems, *FirstElemToReplace, *LastElemToReplace, {C});
replace(Offsets, *FirstElemToReplace, *LastElemToReplace, {Offset});
Size = std::max(Size, Offset + CSize);
NaturalLayout = false;
return true;
179}

181bool 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.
    std::optional<size_t> FirstElemToUpdate = splitAt(OffsetInChars);
    if (!FirstElemToUpdate)
      return false;
    std::optional<size_t> LastElemToUpdate =
        splitAt(OffsetInChars + CharUnits::One());
    if (!LastElemToUpdate)
      return false;
    assert(*LastElemToUpdate - *FirstElemToUpdate < 2 &&(static_cast <bool> (*LastElemToUpdate - *FirstElemToUpdate
 < 2 && "should have at most one element covering one byte"
) ? void (0) : __assert_fail ("*LastElemToUpdate - *FirstElemToUpdate < 2 && \"should have at most one element covering one byte\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 234, __extension__ __PRETTY_FUNCTION__
))
           "should have at most one element covering one byte")(static_cast <bool> (*LastElemToUpdate - *FirstElemToUpdate
 < 2 && "should have at most one element covering one byte"
) ? void (0) : __assert_fail ("*LastElemToUpdate - *FirstElemToUpdate < 2 && \"should have at most one element covering one byte\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 234, __extension__ __PRETTY_FUNCTION__
));

    // 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")(static_cast <bool> (CI->getBitWidth() == CharWidth &&
 "splitAt failed") ? void (0) : __assert_fail ("CI->getBitWidth() == CharWidth && \"splitAt failed\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 260, __extension__ __PRETTY_FUNCTION__
));
      assert((!(CI->getValue() & UpdateMask) || AllowOverwrite) &&(static_cast <bool> ((!(CI->getValue() & UpdateMask
) || AllowOverwrite) && "unexpectedly overwriting bitfield"
) ? void (0) : __assert_fail ("(!(CI->getValue() & UpdateMask) || AllowOverwrite) && \"unexpectedly overwriting bitfield\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 262, __extension__ __PRETTY_FUNCTION__
))
             "unexpectedly overwriting bitfield")(static_cast <bool> ((!(CI->getValue() & UpdateMask
) || AllowOverwrite) && "unexpectedly overwriting bitfield"
) ? void (0) : __assert_fail ("(!(CI->getValue() & UpdateMask) || AllowOverwrite) && \"unexpectedly overwriting bitfield\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 262, __extension__ __PRETTY_FUNCTION__
));
      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;
282}

284/// Returns a position within Elems and Offsets such that all elements
285/// before the returned index end before Pos and all elements at or after
286/// the returned index begin at or after Pos. Splits elements as necessary
287/// to ensure this. Returns std::nullopt if we find something we can't split.
288std::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 std::nullopt;
}
311}

313/// Split the constant at index Index, if possible. Return true if we did.
314/// Hint indicates the location at which we'd like to split, but may be
315/// ignored.
316bool 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)) {
  // Expand the sequence into its contained elements.
  // FIXME: This assumes vector elements are byte-sized.
  replace(Elems, Index, Index + 1,
          llvm::map_range(llvm::seq(0u, CA->getNumOperands()),
                          [&](unsigned Op) { return CA->getOperand(Op); }));
  if (isa<llvm::ArrayType>(CA->getType()) ||
      isa<llvm::VectorType>(CA->getType())) {
    // Array or vector.
    llvm::Type *ElemTy =
        llvm::GetElementPtrInst::getTypeAtIndex(CA->getType(), (uint64_t)0);
    CharUnits ElemSize = getSize(ElemTy);
    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)) {
  // Expand the sequence into its contained elements.
  // FIXME: This assumes vector elements are byte-sized.
  // 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)) {
  // Split into two zeros at the hinted offset.
  CharUnits ElemSize = getSize(C);
  assert(Hint > Offset && Hint < Offset + ElemSize && "nothing to split")(static_cast <bool> (Hint > Offset && Hint <
 Offset + ElemSize && "nothing to split") ? void (0) :
 __assert_fail ("Hint > Offset && Hint < Offset + ElemSize && \"nothing to split\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 372, __extension__ __PRETTY_FUNCTION__
));
  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)) {
  // Drop undef; it doesn't contribute to the final layout.
  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;
391}

393static llvm::Constant *
394EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
                llvm::Type *CommonElementType, unsigned ArrayBound,
                SmallVectorImpl<llvm::Constant *> &Elements,
                llvm::Constant *Filler);

399llvm::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")(static_cast <bool> (!AllowOversized && "oversized array emission not supported"
) ? void (0) : __assert_fail ("!AllowOversized && \"oversized array emission not supported\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 413, __extension__ __PRETTY_FUNCTION__
));

  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.
}

// The size of the constant we plan to generate.  This is usually just
// the size of the initialized type, but in AllowOversized mode (i.e.
// flexible array init), it can be larger.
CharUnits DesiredSize = Utils.getSize(DesiredTy);
if (Size > DesiredSize) {
  assert(AllowOversized && "Elems are oversized")(static_cast <bool> (AllowOversized && "Elems are oversized"
) ? void (0) : __assert_fail ("AllowOversized && \"Elems are oversized\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 448, __extension__ __PRETTY_FUNCTION__
));
  DesiredSize = Size;
}

// The natural alignment of an unpacked LLVM struct with the given elements.
CharUnits Align = CharUnits::One();
for (llvm::Constant *C : Elems)
  Align = std::max(Align, Utils.getAlignment(C));

// The natural size of an unpacked LLVM struct with the given elements.
CharUnits AlignedSize = Size.alignTo(Align);

bool Packed = false;
ArrayRef<llvm::Constant*> UnpackedElems = Elems;
llvm::SmallVector<llvm::Constant*, 32> UnpackedElemStorage;
if (DesiredSize < AlignedSize || DesiredSize.alignTo(Align) != DesiredSize) {
  // The natural layout would be too big; force use of a packed layout.
  NaturalLayout = false;
  Packed = true;
} else if (DesiredSize > AlignedSize) {
  // The natural layout would be too small. Add padding to fix it. (This
  // is ignored if we choose a packed layout.)
  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")(static_cast <bool> (DesiredOffset >= SizeSoFar &&
 "elements out of order") ? void (0) : __assert_fail ("DesiredOffset >= SizeSoFar && \"elements out of order\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 485, __extension__ __PRETTY_FUNCTION__
));

    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 &&(static_cast <bool> (SizeSoFar <= DesiredSize &&
 "requested size is too small for contents") ? void (0) : __assert_fail
 ("SizeSoFar <= DesiredSize && \"requested size is too small for contents\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 498, __extension__ __PRETTY_FUNCTION__
))
           "requested size is too small for contents")(static_cast <bool> (SizeSoFar <= DesiredSize &&
 "requested size is too small for contents") ? void (0) : __assert_fail
 ("SizeSoFar <= DesiredSize && \"requested size is too small for contents\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 498, __extension__ __PRETTY_FUNCTION__
));
    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);
515}

517void ConstantAggregateBuilder::condense(CharUnits Offset,
                                      llvm::Type *DesiredTy) {
CharUnits Size = getSize(DesiredTy);

std::optional<size_t> FirstElemToReplace = splitAt(Offset);
if (!FirstElemToReplace)
  return;
size_t First = *FirstElemToReplace;

std::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, ArrayRef(Elems).slice(First, Length),
    ArrayRef(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});
552}

554//===----------------------------------------------------------------------===//
555//                            ConstStructBuilder
556//===----------------------------------------------------------------------===//

558class ConstStructBuilder {
CodeGenModule &CGM;
ConstantEmitter &Emitter;
ConstantAggregateBuilder &Builder;
CharUnits StartOffset;

564public:
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);

573private:
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);
592};

594bool 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);
602}

604bool ConstStructBuilder::AppendBytes(CharUnits FieldOffsetInChars,
                                   llvm::Constant *InitCst,
                                   bool AllowOverwrite) {
return Builder.add(InitCst, StartOffset + FieldOffsetInChars, AllowOverwrite);
608}

610bool ConstStructBuilder::AppendBitField(
  const FieldDecl *Field, uint64_t FieldOffset, llvm::ConstantInt *CI,
  bool AllowOverwrite) {
const CGRecordLayout &RL =
    CGM.getTypes().getCGRecordLayout(Field->getParent());
const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
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 (Info.Size > FieldValue.getBitWidth())
  FieldValue = FieldValue.zext(Info.Size);

// Truncate the size of FieldValue to the bit field size.
if (Info.Size < FieldValue.getBitWidth())
  FieldValue = FieldValue.trunc(Info.Size);

return Builder.addBits(FieldValue,
                       CGM.getContext().toBits(StartOffset) + FieldOffset,
                       AllowOverwrite);
632}

634static bool EmitDesignatedInitUpdater(ConstantEmitter &Emitter,
                                    ConstantAggregateBuilder &Const,
                                    CharUnits Offset, QualType Type,
                                    InitListExpr *Updater) {
if (Type->isRecordType())
4
←
Taking true branch→
  return ConstStructBuilder::UpdateStruct(Emitter, Const, Offset, Updater);
5
←
Calling 'ConstStructBuilder::UpdateStruct'→

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;
683}

685bool ConstStructBuilder::Build(InitListExpr *ILE, bool AllowOverwrite) {
RecordDecl *RD = ILE->getType()->castAs<RecordType>()->getDecl();
7
←
The object is a 'const RecordType *'→
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 *CXXRD8.1
'CXXRD' is null
 = dyn_cast<CXXRecordDecl>(RD))
8
←
Assuming 'RD' is not a 'CastReturnType'→
9
←
Taking false branch→
  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.
  if (Field->isUnnamedBitfield())
10
←
Taking false branch→
    continue;

  // Get the initializer.  A struct can include fields without initializers,
  // we just use explicit null values for them.
  Expr *Init = nullptr;
11
←
'Init' initialized to a null pointer value→
  if (ElementNo < ILE->getNumInits())
12
←
Assuming the condition is false→
    Init = ILE->getInit(ElementNo++);
  if (Init12.1
'Init' is null
 && isa<NoInitExpr>(Init))
    continue;

  // Zero-sized fields are not emitted, but their initializers may still
  // prevent emission of this struct as a constant.
  if (Field->isZeroSize(CGM.getContext())) {
13
←
Assuming the condition is true→
14
←
Taking true branch→
    if (Init->HasSideEffects(CGM.getContext()))
15
←
Called C++ object pointer is null
      return false;
    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;
776}

778namespace {
779struct 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; }
789};
790}

792bool 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 (Layout.hasOwnVFPtr()) {
    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")(static_cast <bool> (!Base->isVirtual() && "should not have virtual bases here"
) ? void (0) : __assert_fail ("!Base->isVirtual() && \"should not have virtual bases here\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 815, __extension__ __PRETTY_FUNCTION__
));
    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;
871}

873llvm::Constant *ConstStructBuilder::Finalize(QualType Type) {
Type = Type.getNonReferenceType();
RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
llvm::Type *ValTy = CGM.getTypes().ConvertType(Type);
return Builder.build(ValTy, RD->hasFlexibleArrayMember());
878}

880llvm::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);
890}

892llvm::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);
904}

906bool ConstStructBuilder::UpdateStruct(ConstantEmitter &Emitter,
                                    ConstantAggregateBuilder &Const,
                                    CharUnits Offset, InitListExpr *Updater) {
return ConstStructBuilder(Emitter, Const, Offset)
6
←
Calling 'ConstStructBuilder::Build'→
    .Build(Updater, /*AllowOverwrite*/ true);
911}

913//===----------------------------------------------------------------------===//
914//                             ConstExprEmitter
915//===----------------------------------------------------------------------===//

917static ConstantAddress
918tryEmitGlobalCompoundLiteral(ConstantEmitter &emitter,
                           const CompoundLiteralExpr *E) {
CodeGenModule &CGM = emitter.CGM;
CharUnits Align = CGM.getContext().getTypeAlignInChars(E->getType());
if (llvm::GlobalVariable *Addr =
        CGM.getAddrOfConstantCompoundLiteralIfEmitted(E))
  return ConstantAddress(Addr, Addr->getValueType(), Align);

LangAS addressSpace = E->getType().getAddressSpace();
llvm::Constant *C = emitter.tryEmitForInitializer(E->getInitializer(),
                                                  addressSpace, E->getType());
if (!C) {
  assert(!E->isFileScope() &&(static_cast <bool> (!E->isFileScope() && "file-scope compound literal did not have constant initializer!"
) ? void (0) : __assert_fail ("!E->isFileScope() && \"file-scope compound literal did not have constant initializer!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 931, __extension__ __PRETTY_FUNCTION__
))
         "file-scope compound literal did not have constant initializer!")(static_cast <bool> (!E->isFileScope() && "file-scope compound literal did not have constant initializer!"
) ? void (0) : __assert_fail ("!E->isFileScope() && \"file-scope compound literal did not have constant initializer!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 931, __extension__ __PRETTY_FUNCTION__
));
  return ConstantAddress::invalid();
}

auto GV = new llvm::GlobalVariable(
    CGM.getModule(), C->getType(),
    CGM.isTypeConstant(E->getType(), true, false),
    llvm::GlobalValue::InternalLinkage, C, ".compoundliteral", nullptr,
    llvm::GlobalVariable::NotThreadLocal,
    CGM.getContext().getTargetAddressSpace(addressSpace));
emitter.finalize(GV);
GV->setAlignment(Align.getAsAlign());
CGM.setAddrOfConstantCompoundLiteral(E, GV);
return ConstantAddress(GV, GV->getValueType(), Align);
945}

947static llvm::Constant *
948EmitArrayConstant(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 &&(static_cast <bool> (Elements.size() >= NonzeroLength
 && "missing initializer for non-zero element") ? void
 (0) : __assert_fail ("Elements.size() >= NonzeroLength && \"missing initializer for non-zero element\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 968, __extension__ __PRETTY_FUNCTION__
))
         "missing initializer for non-zero element")(static_cast <bool> (Elements.size() >= NonzeroLength
 && "missing initializer for non-zero element") ? void
 (0) : __assert_fail ("Elements.size() >= NonzeroLength && \"missing initializer for non-zero element\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 968, __extension__ __PRETTY_FUNCTION__
));

  // 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),
        ArrayRef(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);
1007}

1009// This class only needs to handle arrays, structs and unions. Outside C++11
1010// mode, we don't currently constant fold those types.  All other types are
1011// handled by constant folding.
1012//
1013// Constant folding is currently missing support for a few features supported
1014// here: CK_ToUnion, CK_ReinterpretMemberPointer, and DesignatedInitUpdateExpr.
1015class ConstExprEmitter :
public StmtVisitor<ConstExprEmitter, llvm::Constant*, QualType> {
CodeGenModule &CGM;
ConstantEmitter &Emitter;
llvm::LLVMContext &VMContext;
1020public:
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) {
  if (llvm::Constant *Result = Emitter.tryEmitConstantExpr(CE))
    return Result;
  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() &&(static_cast <bool> (E->getType()->isUnionType() &&
 "Destination type is not union type!") ? void (0) : __assert_fail
 ("E->getType()->isUnionType() && \"Destination type is not union type!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1071, __extension__
 __PRETTY_FUNCTION__))
           "Destination type is not union type!")(static_cast <bool> (E->getType()->isUnionType() &&
 "Destination type is not union type!") ? void (0) : __assert_fail
 ("E->getType()->isUnionType() && \"Destination type is not union type!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1071, __extension__
 __PRETTY_FUNCTION__));

    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!")(static_cast <bool> (CurSize <= TotalSize &&
 "Union size mismatch!") ? void (0) : __assert_fail ("CurSize <= TotalSize && \"Union size mismatch!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1090, __extension__
 __PRETTY_FUNCTION__));
    if (unsigned NumPadBytes = TotalSize - CurSize) {
      llvm::Type *Ty = CGM.CharTy;
      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: {
    // We don't really support doing lvalue-to-rvalue conversions here; any
    // interesting conversions should be done in Evaluate().  But as a
    // special case, allow compound literals to support the gcc extension
    // allowing "struct x {int x;} x = (struct x) {};".
    if (auto *E = dyn_cast<CompoundLiteralExpr>(subExpr->IgnoreParens()))
      return Visit(E->getInitializer(), destType);
    return nullptr;
  }

  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")::llvm::llvm_unreachable_internal("global sampler variables are not generated"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1131);

  case CK_Dependent: llvm_unreachable("saw dependent cast!")::llvm::llvm_unreachable_internal("saw dependent cast!", "clang/lib/CodeGen/CGExprConstant.cpp"
, 1133);

  case CK_BuiltinFnToFnPtr:
    llvm_unreachable("builtin functions are handled elsewhere")::llvm::llvm_unreachable_internal("builtin functions are handled elsewhere"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1136);

  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_FloatingToFixedPoint:
  case CK_FixedPointToFloating:
  case CK_FixedPointCast:
  case CK_FixedPointToBoolean:
  case CK_FixedPointToIntegral:
  case CK_IntegralToFixedPoint:
  case CK_ZeroToOCLOpaqueType:
  case CK_MatrixCast:
    return nullptr;
  }
  llvm_unreachable("Invalid CastKind")::llvm::llvm_unreachable_internal("Invalid CastKind", "clang/lib/CodeGen/CGExprConstant.cpp"
, 1205);
}

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) {
  return Visit(E->getSubExpr(), T);
}

llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
                                              QualType T) {
  return Visit(E->getSubExpr(), 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")(static_cast <bool> (CAT && "can't emit array init for non-constant-bound array"
) ? void (0) : __assert_fail ("CAT && \"can't emit array init for non-constant-bound array\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1225, __extension__
 __PRETTY_FUNCTION__));
  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)
1
Assuming 'C' is non-null→
2
←
Taking false branch→
    return nullptr;

  ConstantAggregateBuilder Const(CGM);
  Const.add(C, CharUnits::Zero(), false);

  if (!EmitDesignatedInitUpdater(Emitter, Const, CharUnits::Zero(), destType,
3
←
Calling 'EmitDesignatedInitUpdater'→
                                 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;

  // Only default and copy/move constructors can be trivial.
  if (E->getNumArgs()) {
    assert(E->getNumArgs() == 1 && "trivial ctor with > 1 argument")(static_cast <bool> (E->getNumArgs() == 1 &&
 "trivial ctor with > 1 argument") ? void (0) : __assert_fail
 ("E->getNumArgs() == 1 && \"trivial ctor with > 1 argument\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1317, __extension__
 __PRETTY_FUNCTION__));
    assert(E->getConstructor()->isCopyOrMoveConstructor() &&(static_cast <bool> (E->getConstructor()->isCopyOrMoveConstructor
() && "trivial ctor has argument but isn't a copy/move ctor"
) ? void (0) : __assert_fail ("E->getConstructor()->isCopyOrMoveConstructor() && \"trivial ctor has argument but isn't a copy/move ctor\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1319, __extension__
 __PRETTY_FUNCTION__))
           "trivial ctor has argument but isn't a copy/move ctor")(static_cast <bool> (E->getConstructor()->isCopyOrMoveConstructor
() && "trivial ctor has argument but isn't a copy/move ctor"
) ? void (0) : __assert_fail ("E->getConstructor()->isCopyOrMoveConstructor() && \"trivial ctor has argument but isn't a copy/move ctor\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1319, __extension__
 __PRETTY_FUNCTION__));

    Expr *Arg = E->getArg(0);
    assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) &&(static_cast <bool> (CGM.getContext().hasSameUnqualifiedType
(Ty, Arg->getType()) && "argument to copy ctor is of wrong type"
) ? void (0) : __assert_fail ("CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) && \"argument to copy ctor is of wrong type\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1323, __extension__
 __PRETTY_FUNCTION__))
           "argument to copy ctor is of wrong type")(static_cast <bool> (CGM.getContext().hasSameUnqualifiedType
(Ty, Arg->getType()) && "argument to copy ctor is of wrong type"
) ? void (0) : __assert_fail ("CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) && \"argument to copy ctor is of wrong type\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1323, __extension__
 __PRETTY_FUNCTION__));

    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);
}
1358};

1360}  // end anonymous namespace.

1362llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C,
                                                      AbstractState saved) {
Abstract = saved.OldValue;

assert(saved.OldPlaceholdersSize == PlaceholderAddresses.size() &&(static_cast <bool> (saved.OldPlaceholdersSize == PlaceholderAddresses
.size() && "created a placeholder while doing an abstract emission?"
) ? void (0) : __assert_fail ("saved.OldPlaceholdersSize == PlaceholderAddresses.size() && \"created a placeholder while doing an abstract emission?\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1367, __extension__
 __PRETTY_FUNCTION__))
       "created a placeholder while doing an abstract emission?")(static_cast <bool> (saved.OldPlaceholdersSize == PlaceholderAddresses
.size() && "created a placeholder while doing an abstract emission?"
) ? void (0) : __assert_fail ("saved.OldPlaceholdersSize == PlaceholderAddresses.size() && \"created a placeholder while doing an abstract emission?\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1367, __extension__
 __PRETTY_FUNCTION__));

// No validation necessary for now.
// No cleanup to do for now.
return C;
1372}

1374llvm::Constant *
1375ConstantEmitter::tryEmitAbstractForInitializer(const VarDecl &D) {
auto state = pushAbstract();
auto C = tryEmitPrivateForVarInit(D);
return validateAndPopAbstract(C, state);
1379}

1381llvm::Constant *
1382ConstantEmitter::tryEmitAbstract(const Expr *E, QualType destType) {
auto state = pushAbstract();
auto C = tryEmitPrivate(E, destType);
return validateAndPopAbstract(C, state);
1386}

1388llvm::Constant *
1389ConstantEmitter::tryEmitAbstract(const APValue &value, QualType destType) {
auto state = pushAbstract();
auto C = tryEmitPrivate(value, destType);
return validateAndPopAbstract(C, state);
1393}

1395llvm::Constant *ConstantEmitter::tryEmitConstantExpr(const ConstantExpr *CE) {
if (!CE->hasAPValueResult())
  return nullptr;

QualType RetType = CE->getType();
if (CE->isGLValue())
  RetType = CGM.getContext().getLValueReferenceType(RetType);

return emitAbstract(CE->getBeginLoc(), CE->getAPValueResult(), RetType);
1404}

1406llvm::Constant *
1407ConstantEmitter::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;
1417}

1419llvm::Constant *
1420ConstantEmitter::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;
1431}

1433llvm::Constant *ConstantEmitter::tryEmitForInitializer(const VarDecl &D) {
initializeNonAbstract(D.getType().getAddressSpace());
return markIfFailed(tryEmitPrivateForVarInit(D));
1436}

1438llvm::Constant *ConstantEmitter::tryEmitForInitializer(const Expr *E,
                                                     LangAS destAddrSpace,
                                                     QualType destType) {
initializeNonAbstract(destAddrSpace);
return markIfFailed(tryEmitPrivateForMemory(E, destType));
1443}

1445llvm::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?")(static_cast <bool> (C && "couldn't emit constant value non-abstractly?"
) ? void (0) : __assert_fail ("C && \"couldn't emit constant value non-abstractly?\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1450, __extension__
 __PRETTY_FUNCTION__));
return C;
1452}

1454llvm::GlobalValue *ConstantEmitter::getCurrentAddrPrivate() {
assert(!Abstract && "cannot get current address for abstract constant")(static_cast <bool> (!Abstract && "cannot get current address for abstract constant"
) ? void (0) : __assert_fail ("!Abstract && \"cannot get current address for abstract constant\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1455, __extension__
 __PRETTY_FUNCTION__));



// 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;
1472}

1474void ConstantEmitter::registerCurrentAddrPrivate(llvm::Constant *signal,
                                         llvm::GlobalValue *placeholder) {
assert(!PlaceholderAddresses.empty())(static_cast <bool> (!PlaceholderAddresses.empty()) ? void
 (0) : __assert_fail ("!PlaceholderAddresses.empty()", "clang/lib/CodeGen/CGExprConstant.cpp"
, 1476, __extension__ __PRETTY_FUNCTION__));
assert(PlaceholderAddresses.back().first == nullptr)(static_cast <bool> (PlaceholderAddresses.back().first ==
 nullptr) ? void (0) : __assert_fail ("PlaceholderAddresses.back().first == nullptr"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1477, __extension__
 __PRETTY_FUNCTION__));
assert(PlaceholderAddresses.back().second == placeholder)(static_cast <bool> (PlaceholderAddresses.back().second
 == placeholder) ? void (0) : __assert_fail ("PlaceholderAddresses.back().second == placeholder"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1478, __extension__
 __PRETTY_FUNCTION__));
PlaceholderAddresses.back().first = signal;
1480}

1482namespace {
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")(static_cast <bool> (IndexValues.size() == Indices.size
() && "mismatch") ? void (0) : __assert_fail ("IndexValues.size() == Indices.size() && \"mismatch\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1521, __extension__
 __PRETTY_FUNCTION__));
    assert(Indices.size() == 1 && "didn't pop all indices")(static_cast <bool> (Indices.size() == 1 && "didn't pop all indices"
) ? void (0) : __assert_fail ("Indices.size() == 1 && \"didn't pop all indices\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1522, __extension__
 __PRETTY_FUNCTION__));

    // Do the replacement; this basically invalidates 'init'.
    assert(Locations.size() == PlaceholderAddresses.size() &&(static_cast <bool> (Locations.size() == PlaceholderAddresses
.size() && "missed a placeholder?") ? void (0) : __assert_fail
 ("Locations.size() == PlaceholderAddresses.size() && \"missed a placeholder?\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1526, __extension__
 __PRETTY_FUNCTION__))
           "missed a placeholder?")(static_cast <bool> (Locations.size() == PlaceholderAddresses
.size() && "missed a placeholder?") ? void (0) : __assert_fail
 ("Locations.size() == PlaceholderAddresses.size() && \"missed a placeholder?\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1526, __extension__
 __PRETTY_FUNCTION__));

    // 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!")(static_cast <bool> (entry.first->getParent() == nullptr
 && "not a placeholder!") ? void (0) : __assert_fail (
"entry.first->getParent() == nullptr && \"not a placeholder!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1533, __extension__
 __PRETTY_FUNCTION__));
      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.contains(placeholder) &&(static_cast <bool> (!Locations.contains(placeholder) &&
 "already found location for placeholder!") ? void (0) : __assert_fail
 ("!Locations.contains(placeholder) && \"already found location for placeholder!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1574, __extension__
 __PRETTY_FUNCTION__))
           "already found location for placeholder!")(static_cast <bool> (!Locations.contains(placeholder) &&
 "already found location for placeholder!") ? void (0) : __assert_fail
 ("!Locations.contains(placeholder) && \"already found location for placeholder!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1574, __extension__
 __PRETTY_FUNCTION__));

    // 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())(static_cast <bool> (Indices.size() == IndexValues.size
()) ? void (0) : __assert_fail ("Indices.size() == IndexValues.size()"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1579, __extension__
 __PRETTY_FUNCTION__));
    for (size_t i = Indices.size() - 1; i != size_t(-1); --i) {
      if (IndexValues[i]) {
1582#ifndef NDEBUG
        for (size_t j = 0; j != i + 1; ++j) {
          assert(IndexValues[j] &&(static_cast <bool> (IndexValues[j] && isa<llvm
::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt
>(IndexValues[j])->getZExtValue() == Indices[j]) ? void
 (0) : __assert_fail ("IndexValues[j] && isa<llvm::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue() == Indices[j]"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1587, __extension__
 __PRETTY_FUNCTION__))
                 isa<llvm::ConstantInt>(IndexValues[j]) &&(static_cast <bool> (IndexValues[j] && isa<llvm
::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt
>(IndexValues[j])->getZExtValue() == Indices[j]) ? void
 (0) : __assert_fail ("IndexValues[j] && isa<llvm::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue() == Indices[j]"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1587, __extension__
 __PRETTY_FUNCTION__))
                 cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue()(static_cast <bool> (IndexValues[j] && isa<llvm
::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt
>(IndexValues[j])->getZExtValue() == Indices[j]) ? void
 (0) : __assert_fail ("IndexValues[j] && isa<llvm::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue() == Indices[j]"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1587, __extension__
 __PRETTY_FUNCTION__))
                   == Indices[j])(static_cast <bool> (IndexValues[j] && isa<llvm
::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt
>(IndexValues[j])->getZExtValue() == Indices[j]) ? void
 (0) : __assert_fail ("IndexValues[j] && isa<llvm::ConstantInt>(IndexValues[j]) && cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue() == Indices[j]"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1587, __extension__
 __PRETTY_FUNCTION__));
        }
1589#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});
  }
};
1607}

1609void ConstantEmitter::finalize(llvm::GlobalVariable *global) {
assert(InitializedNonAbstract &&(static_cast <bool> (InitializedNonAbstract && "finalizing emitter that was used for abstract emission?"
) ? void (0) : __assert_fail ("InitializedNonAbstract && \"finalizing emitter that was used for abstract emission?\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1611, __extension__
 __PRETTY_FUNCTION__))
       "finalizing emitter that was used for abstract emission?")(static_cast <bool> (InitializedNonAbstract && "finalizing emitter that was used for abstract emission?"
) ? void (0) : __assert_fail ("InitializedNonAbstract && \"finalizing emitter that was used for abstract emission?\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1611, __extension__
 __PRETTY_FUNCTION__));
assert(!Finalized && "finalizing emitter multiple times")(static_cast <bool> (!Finalized && "finalizing emitter multiple times"
) ? void (0) : __assert_fail ("!Finalized && \"finalizing emitter multiple times\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1612, __extension__
 __PRETTY_FUNCTION__));
assert(global->getInitializer())(static_cast <bool> (global->getInitializer()) ? void
 (0) : __assert_fail ("global->getInitializer()", "clang/lib/CodeGen/CGExprConstant.cpp"
, 1613, __extension__ __PRETTY_FUNCTION__));

// Note that we might also be Failed.
Finalized = true;

if (!PlaceholderAddresses.empty()) {
  ReplacePlaceholders(CGM, global, PlaceholderAddresses)
    .replaceInInitializer(global->getInitializer());
  PlaceholderAddresses.clear(); // satisfy
}
1623}

1625ConstantEmitter::~ConstantEmitter() {
assert((!InitializedNonAbstract || Finalized || Failed) &&(static_cast <bool> ((!InitializedNonAbstract || Finalized
 || Failed) && "not finalized after being initialized for non-abstract emission"
) ? void (0) : __assert_fail ("(!InitializedNonAbstract || Finalized || Failed) && \"not finalized after being initialized for non-abstract emission\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1627, __extension__
 __PRETTY_FUNCTION__))
       "not finalized after being initialized for non-abstract emission")(static_cast <bool> ((!InitializedNonAbstract || Finalized
 || Failed) && "not finalized after being initialized for non-abstract emission"
) ? void (0) : __assert_fail ("(!InitializedNonAbstract || Finalized || Failed) && \"not finalized after being initialized for non-abstract emission\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1627, __extension__
 __PRETTY_FUNCTION__));
assert(PlaceholderAddresses.empty() && "unhandled placeholders")(static_cast <bool> (PlaceholderAddresses.empty() &&
 "unhandled placeholders") ? void (0) : __assert_fail ("PlaceholderAddresses.empty() && \"unhandled placeholders\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1628, __extension__
 __PRETTY_FUNCTION__));
1629}

1631static QualType getNonMemoryType(CodeGenModule &CGM, QualType type) {
if (auto AT = type->getAs<AtomicType>()) {
  return CGM.getContext().getQualifiedType(AT->getValueType(),
                                           type.getQualifiers());
}
return type;
1637}

1639llvm::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 = D.hasConstantInitialization();

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")(static_cast <bool> (E && "No initializer to emit"
) ? void (0) : __assert_fail ("E && \"No initializer to emit\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1673, __extension__
 __PRETTY_FUNCTION__));

auto nonMemoryDestType = getNonMemoryType(CGM, destType);
auto C =
  ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), nonMemoryDestType);
return (C ? emitForMemory(C, destType) : nullptr);
1679}

1681llvm::Constant *
1682ConstantEmitter::tryEmitAbstractForMemory(const Expr *E, QualType destType) {
auto nonMemoryDestType = getNonMemoryType(CGM, destType);
auto C = tryEmitAbstract(E, nonMemoryDestType);
return (C ? emitForMemory(C, destType) : nullptr);
1686}

1688llvm::Constant *
1689ConstantEmitter::tryEmitAbstractForMemory(const APValue &value,
                                        QualType destType) {
auto nonMemoryDestType = getNonMemoryType(CGM, destType);
auto C = tryEmitAbstract(value, nonMemoryDestType);
return (C ? emitForMemory(C, destType) : nullptr);
1694}

1696llvm::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);
1701}

1703llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const APValue &value,
                                                       QualType destType) {
auto nonMemoryDestType = getNonMemoryType(CGM, destType);
auto C = tryEmitPrivate(value, nonMemoryDestType);
return (C ? emitForMemory(C, destType) : nullptr);
1708}

1710llvm::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")(static_cast <bool> (innerSize < outerSize &&
 "emitted over-large constant for atomic") ? void (0) : __assert_fail
 ("innerSize < outerSize && \"emitted over-large constant for atomic\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1723, __extension__
 __PRETTY_FUNCTION__));
  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;
1739}

1741llvm::Constant *ConstantEmitter::tryEmitPrivate(const Expr *E,
                                              QualType destType) {
assert(!destType->isVoidType() && "can't emit a void constant")(static_cast <bool> (!destType->isVoidType() &&
 "can't emit a void constant") ? void (0) : __assert_fail ("!destType->isVoidType() && \"can't emit a void constant\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 1743, __extension__
 __PRETTY_FUNCTION__));

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;
1761}

1763llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) {
return getTargetCodeGenInfo().getNullPointer(*this, T, QT);
1765}

1767namespace {
1768/// A struct which can be used to peephole certain kinds of finalization
1769/// that normally happen during l-value emission.
1770struct ConstantLValue {
llvm::Constant *Value;
bool HasOffsetApplied;

/*implicit*/ ConstantLValue(llvm::Constant *value,
                            bool hasOffsetApplied = false)
  : Value(value), HasOffsetApplied(hasOffsetApplied) {}

/*implicit*/ ConstantLValue(ConstantAddress address)
  : ConstantLValue(address.getPointer()) {}
1780};

1782/// A helper class for emitting constant l-values.
1783class 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;

1793public:
ConstantLValueEmitter(ConstantEmitter &emitter, const APValue &value,
                      QualType destType)
  : CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType) {}

llvm::Constant *tryEmit();

1800private:
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 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;
}
1842};

1844}

1846llvm::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))(static_cast <bool> (isa<llvm::IntegerType>(destTy
) || isa<llvm::PointerType>(destTy)) ? void (0) : __assert_fail
 ("isa<llvm::IntegerType>(destTy) || isa<llvm::PointerType>(destTy)"
, "clang/lib/CodeGen/CGExprConstant.cpp", 1857, __extension__
 __PRETTY_FUNCTION__));

// 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);
1883}

1885/// Try to emit an absolute l-value, such as a null pointer or an integer
1886/// bitcast to pointer type.
1887llvm::Constant *
1888ConstantLValueEmitter::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;
1905}

1907ConstantLValue
1908ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) {
// Handle values.
if (const ValueDecl *D = base.dyn_cast<const ValueDecl*>()) {
  // The constant always points to the canonical declaration. We want to look
  // at properties of the most recent declaration at the point of emission.
  D = cast<ValueDecl>(D->getMostRecentDecl());

  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));
      }
    }
  }

  if (auto *GD = dyn_cast<MSGuidDecl>(D))
    return CGM.GetAddrOfMSGuidDecl(GD);

  if (auto *GCD = dyn_cast<UnnamedGlobalConstantDecl>(D))
    return CGM.GetAddrOfUnnamedGlobalConstantDecl(GCD);

  if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(D))
    return CGM.GetAddrOfTemplateParamObject(TPO);

  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*>());
1959}

1961ConstantLValue
1962ConstantLValueEmitter::VisitConstantExpr(const ConstantExpr *E) {
if (llvm::Constant *Result = Emitter.tryEmitConstantExpr(E))
  return Result;
return Visit(E->getSubExpr());
1966}

1968ConstantLValue
1969ConstantLValueEmitter::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
ConstantEmitter CompoundLiteralEmitter(CGM, Emitter.CGF);
CompoundLiteralEmitter.setInConstantContext(Emitter.isInConstantContext());
return tryEmitGlobalCompoundLiteral(CompoundLiteralEmitter, E);
1973}

1975ConstantLValue
1976ConstantLValueEmitter::VisitStringLiteral(const StringLiteral *E) {
return CGM.GetAddrOfConstantStringFromLiteral(E);
1978}

1980ConstantLValue
1981ConstantLValueEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
return CGM.GetAddrOfConstantStringFromObjCEncode(E);
1983}

1985static ConstantLValue emitConstantObjCStringLiteral(const StringLiteral *S,
                                                  QualType T,
                                                  CodeGenModule &CGM) {
auto C = CGM.getObjCRuntime().GenerateConstantString(S);
return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(T));
1990}

1992ConstantLValue
1993ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) {
return emitConstantObjCStringLiteral(E->getString(), E->getType(), CGM);
1995}

1997ConstantLValue
1998ConstantLValueEmitter::VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
assert(E->isExpressibleAsConstantInitializer() &&(static_cast <bool> (E->isExpressibleAsConstantInitializer
() && "this boxed expression can't be emitted as a compile-time constant"
) ? void (0) : __assert_fail ("E->isExpressibleAsConstantInitializer() && \"this boxed expression can't be emitted as a compile-time constant\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 2000, __extension__
 __PRETTY_FUNCTION__))
       "this boxed expression can't be emitted as a compile-time constant")(static_cast <bool> (E->isExpressibleAsConstantInitializer
() && "this boxed expression can't be emitted as a compile-time constant"
) ? void (0) : __assert_fail ("E->isExpressibleAsConstantInitializer() && \"this boxed expression can't be emitted as a compile-time constant\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 2000, __extension__
 __PRETTY_FUNCTION__));
auto *SL = cast<StringLiteral>(E->getSubExpr()->IgnoreParenCasts());
return emitConstantObjCStringLiteral(SL, E->getType(), CGM);
2003}

2005ConstantLValue
2006ConstantLValueEmitter::VisitPredefinedExpr(const PredefinedExpr *E) {
return CGM.GetAddrOfConstantStringFromLiteral(E->getFunctionName());
2008}

2010ConstantLValue
2011ConstantLValueEmitter::VisitAddrLabelExpr(const AddrLabelExpr *E) {
assert(Emitter.CGF && "Invalid address of label expression outside function")(static_cast <bool> (Emitter.CGF && "Invalid address of label expression outside function"
) ? void (0) : __assert_fail ("Emitter.CGF && \"Invalid address of label expression outside function\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 2012, __extension__
 __PRETTY_FUNCTION__));
llvm::Constant *Ptr = Emitter.CGF->GetAddrOfLabel(E->getLabel());
Ptr = llvm::ConstantExpr::getBitCast(Ptr,
                                 CGM.getTypes().ConvertType(E->getType()));
return Ptr;
2017}

2019ConstantLValue
2020ConstantLValueEmitter::VisitCallExpr(const CallExpr *E) {
unsigned builtin = E->getBuiltinCallee();
if (builtin == Builtin::BI__builtin_function_start)
  return CGM.GetFunctionStart(
      E->getArg(0)->getAsBuiltinConstantDeclRef(CGM.getContext()));
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);
}
2036}

2038ConstantLValue
2039ConstantLValueEmitter::VisitBlockExpr(const BlockExpr *E) {
StringRef functionName;
if (auto CGF = Emitter.CGF)
  functionName = CGF->CurFn->getName();
else
  functionName = "global";

return CGM.GetAddrOfGlobalBlock(E, functionName);
2047}

2049ConstantLValue
2050ConstantLValueEmitter::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
QualType T;
if (E->isTypeOperand())
  T = E->getTypeOperand(CGM.getContext());
else
  T = E->getExprOperand()->getType();
return CGM.GetAddrOfRTTIDescriptor(T);
2057}

2059ConstantLValue
2060ConstantLValueEmitter::VisitMaterializeTemporaryExpr(
                                          const MaterializeTemporaryExpr *E) {
assert(E->getStorageDuration() == SD_Static)(static_cast <bool> (E->getStorageDuration() == SD_Static
) ? void (0) : __assert_fail ("E->getStorageDuration() == SD_Static"
, "clang/lib/CodeGen/CGExprConstant.cpp", 2062, __extension__
 __PRETTY_FUNCTION__));
SmallVector<const Expr *, 2> CommaLHSs;
SmallVector<SubobjectAdjustment, 2> Adjustments;
const Expr *Inner =
    E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
return CGM.GetAddrOfGlobalTemporary(E, Inner);
2068}

2070llvm::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")::llvm::llvm_unreachable_internal("unsupported vector element type"
, "clang/lib/CodeGen/CGExprConstant.cpp", 2131);
  }
  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 ArrayType *ArrayTy = CGM.getContext().getAsArrayType(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(),
                                      ArrayTy->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), ArrayTy->getElementType());
    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(DestType));
  return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
                           Filler);
}
case APValue::MemberPointer:
  return CGM.getCXXABI().EmitMemberPointer(Value, DestType);
}
llvm_unreachable("Unknown APValue kind")::llvm::llvm_unreachable_internal("Unknown APValue kind", "clang/lib/CodeGen/CGExprConstant.cpp"
, 2198);
2199}

2201llvm::GlobalVariable *CodeGenModule::getAddrOfConstantCompoundLiteralIfEmitted(
  const CompoundLiteralExpr *E) {
return EmittedCompoundLiterals.lookup(E);
2204}

2206void 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!")(static_cast <bool> (Ok && "CLE has already been emitted!"
) ? void (0) : __assert_fail ("Ok && \"CLE has already been emitted!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 2210, __extension__
 __PRETTY_FUNCTION__));
2211}

2213ConstantAddress
2214CodeGenModule::GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr *E) {
assert(E->isFileScope() && "not a file-scope compound literal expr")(static_cast <bool> (E->isFileScope() && "not a file-scope compound literal expr"
) ? void (0) : __assert_fail ("E->isFileScope() && \"not a file-scope compound literal expr\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 2215, __extension__
 __PRETTY_FUNCTION__));
ConstantEmitter emitter(*this);
return tryEmitGlobalCompoundLiteral(emitter, E);
2218}

2220llvm::Constant *
2221CodeGenModule::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);
2234}

2236static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
                                             llvm::Type *baseType,
                                             const CXXRecordDecl *base);

2240static 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);
2322}

2324/// Emit the null constant for a base subobject.
2325static 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);
2336}

2338llvm::Constant *ConstantEmitter::emitNullForMemory(CodeGenModule &CGM,
                                                 QualType T) {
return emitForMemory(CGM, CGM.EmitNullConstant(T), T);
2341}

2343llvm::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() &&(static_cast <bool> (T->isMemberDataPointerType() &&
 "Should only see pointers to data members here!") ? void (0)
 : __assert_fail ("T->isMemberDataPointerType() && \"Should only see pointers to data members here!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 2368, __extension__
 __PRETTY_FUNCTION__))
       "Should only see pointers to data members here!")(static_cast <bool> (T->isMemberDataPointerType() &&
 "Should only see pointers to data members here!") ? void (0)
 : __assert_fail ("T->isMemberDataPointerType() && \"Should only see pointers to data members here!\""
, "clang/lib/CodeGen/CGExprConstant.cpp", 2368, __extension__
 __PRETTY_FUNCTION__));

return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>());
2371}

2373llvm::Constant *
2374CodeGenModule::EmitNullConstantForBase(const CXXRecordDecl *Record) {
return ::EmitNullConstant(*this, Record, false);
2376}