Coverage Report

Created: 2022-05-14 11:35

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/CodeGen/CGExprConstant.cpp
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//===--- CGExprConstant.cpp - Emit LLVM Code from Constant Expressions ----===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code to emit Constant Expr nodes as LLVM code.
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//
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//===----------------------------------------------------------------------===//
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#include "CGCXXABI.h"
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#include "CGObjCRuntime.h"
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#include "CGRecordLayout.h"
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#include "CodeGenFunction.h"
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#include "CodeGenModule.h"
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#include "ConstantEmitter.h"
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#include "TargetInfo.h"
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#include "clang/AST/APValue.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/Attr.h"
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#include "clang/AST/RecordLayout.h"
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#include "clang/AST/StmtVisitor.h"
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#include "clang/Basic/Builtins.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/Sequence.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GlobalVariable.h"
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using namespace clang;
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using namespace CodeGen;
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//===----------------------------------------------------------------------===//
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//                            ConstantAggregateBuilder
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//===----------------------------------------------------------------------===//
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namespace {
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class ConstExprEmitter;
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struct ConstantAggregateBuilderUtils {
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  CodeGenModule &CGM;
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11.5k
  ConstantAggregateBuilderUtils(CodeGenModule &CGM) : CGM(CGM) {}
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22.7k
  CharUnits getAlignment(const llvm::Constant *C) const {
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22.7k
    return CharUnits::fromQuantity(
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22.7k
        CGM.getDataLayout().getABITypeAlignment(C->getType()));
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22.7k
  }
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17.3k
  CharUnits getSize(llvm::Type *Ty) const {
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17.3k
    return CharUnits::fromQuantity(CGM.getDataLayout().getTypeAllocSize(Ty));
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17.3k
  }
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11.6k
  CharUnits getSize(const llvm::Constant *C) const {
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11.6k
    return getSize(C->getType());
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11.6k
  }
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456
  llvm::Constant *getPadding(CharUnits PadSize) const {
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456
    llvm::Type *Ty = CGM.CharTy;
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456
    if (PadSize > CharUnits::One())
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417
      Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity());
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456
    return llvm::UndefValue::get(Ty);
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456
  }
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8
  llvm::Constant *getZeroes(CharUnits ZeroSize) const {
68
8
    llvm::Type *Ty = llvm::ArrayType::get(CGM.CharTy, ZeroSize.getQuantity());
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8
    return llvm::ConstantAggregateZero::get(Ty);
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8
  }
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};
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/// Incremental builder for an llvm::Constant* holding a struct or array
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/// constant.
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class ConstantAggregateBuilder : private ConstantAggregateBuilderUtils {
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  /// The elements of the constant. These two arrays must have the same size;
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  /// Offsets[i] describes the offset of Elems[i] within the constant. The
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  /// elements are kept in increasing offset order, and we ensure that there
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  /// is no overlap: Offsets[i+1] >= Offsets[i] + getSize(Elemes[i]).
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  ///
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  /// This may contain explicit padding elements (in order to create a
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  /// natural layout), but need not. Gaps between elements are implicitly
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  /// considered to be filled with undef.
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  llvm::SmallVector<llvm::Constant*, 32> Elems;
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  llvm::SmallVector<CharUnits, 32> Offsets;
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  /// The size of the constant (the maximum end offset of any added element).
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  /// May be larger than the end of Elems.back() if we split the last element
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  /// and removed some trailing undefs.
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  CharUnits Size = CharUnits::Zero();
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  /// This is true only if laying out Elems in order as the elements of a
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  /// non-packed LLVM struct will give the correct layout.
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  bool NaturalLayout = true;
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  bool split(size_t Index, CharUnits Hint);
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  Optional<size_t> splitAt(CharUnits Pos);
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  static llvm::Constant *buildFrom(CodeGenModule &CGM,
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                                   ArrayRef<llvm::Constant *> Elems,
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                                   ArrayRef<CharUnits> Offsets,
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                                   CharUnits StartOffset, CharUnits Size,
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                                   bool NaturalLayout, llvm::Type *DesiredTy,
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                                   bool AllowOversized);
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public:
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  ConstantAggregateBuilder(CodeGenModule &CGM)
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5.78k
      : ConstantAggregateBuilderUtils(CGM) {}
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  /// Update or overwrite the value starting at \p Offset with \c C.
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  ///
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  /// \param AllowOverwrite If \c true, this constant might overwrite (part of)
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  ///        a constant that has already been added. This flag is only used to
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  ///        detect bugs.
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  bool add(llvm::Constant *C, CharUnits Offset, bool AllowOverwrite);
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  /// Update or overwrite the bits starting at \p OffsetInBits with \p Bits.
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  bool addBits(llvm::APInt Bits, uint64_t OffsetInBits, bool AllowOverwrite);
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  /// Attempt to condense the value starting at \p Offset to a constant of type
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  /// \p DesiredTy.
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  void condense(CharUnits Offset, llvm::Type *DesiredTy);
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  /// Produce a constant representing the entire accumulated value, ideally of
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  /// the specified type. If \p AllowOversized, the constant might be larger
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  /// than implied by \p DesiredTy (eg, if there is a flexible array member).
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  /// Otherwise, the constant will be of exactly the same size as \p DesiredTy
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  /// even if we can't represent it as that type.
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5.74k
  llvm::Constant *build(llvm::Type *DesiredTy, bool AllowOversized) const {
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5.74k
    return buildFrom(CGM, Elems, Offsets, CharUnits::Zero(), Size,
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5.74k
                     NaturalLayout, DesiredTy, AllowOversized);
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  }
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};
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template<typename Container, typename Range = std::initializer_list<
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                                 typename Container::value_type>>
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static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
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  assert(BeginOff <= EndOff && "invalid replacement range");
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0
  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
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}
CGExprConstant.cpp:void (anonymous namespace)::replace<llvm::SmallVector<llvm::Constant*, 32u>, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_0, llvm::Constant*> > >(llvm::SmallVector<llvm::Constant*, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_0, llvm::Constant*> >)
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137
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static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
138
34
  assert(BeginOff <= EndOff && "invalid replacement range");
139
0
  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
140
34
}
CGExprConstant.cpp:void (anonymous namespace)::replace<llvm::SmallVector<clang::CharUnits, 32u>, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_1, clang::CharUnits> > >(llvm::SmallVector<clang::CharUnits, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_1, clang::CharUnits> >)
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137
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static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
138
2
  assert(BeginOff <= EndOff && "invalid replacement range");
139
0
  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
140
2
}
CGExprConstant.cpp:void (anonymous namespace)::replace<llvm::SmallVector<clang::CharUnits, 32u>, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_2, clang::CharUnits> > >(llvm::SmallVector<clang::CharUnits, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_2, clang::CharUnits> >)
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static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
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  assert(BeginOff <= EndOff && "invalid replacement range");
139
0
  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
140
32
}
CGExprConstant.cpp:void (anonymous namespace)::replace<llvm::SmallVector<llvm::Constant*, 32u>, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_3, llvm::Constant*> > >(llvm::SmallVector<llvm::Constant*, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_3, llvm::Constant*> >)
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137
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static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
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15
  assert(BeginOff <= EndOff && "invalid replacement range");
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0
  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
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15
}
CGExprConstant.cpp:void (anonymous namespace)::replace<llvm::SmallVector<clang::CharUnits, 32u>, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_4, clang::CharUnits> > >(llvm::SmallVector<clang::CharUnits, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::SafeIntIterator<unsigned int, false>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_4, clang::CharUnits> >)
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137
15
static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
138
15
  assert(BeginOff <= EndOff && "invalid replacement range");
139
0
  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
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15
}
CGExprConstant.cpp:void (anonymous namespace)::replace<llvm::SmallVector<llvm::Constant*, 32u>, std::initializer_list<llvm::Constant*> >(llvm::SmallVector<llvm::Constant*, 32u>&, unsigned long, unsigned long, std::initializer_list<llvm::Constant*>)
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137
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static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
138
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  assert(BeginOff <= EndOff && "invalid replacement range");
139
0
  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
140
110
}
CGExprConstant.cpp:void (anonymous namespace)::replace<llvm::SmallVector<clang::CharUnits, 32u>, std::initializer_list<clang::CharUnits> >(llvm::SmallVector<clang::CharUnits, 32u>&, unsigned long, unsigned long, std::initializer_list<clang::CharUnits>)
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137
110
static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
138
110
  assert(BeginOff <= EndOff && "invalid replacement range");
139
0
  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
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110
}
141
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bool ConstantAggregateBuilder::add(llvm::Constant *C, CharUnits Offset,
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11.2k
                          bool AllowOverwrite) {
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  // Common case: appending to a layout.
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11.2k
  if (Offset >= Size) {
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11.1k
    CharUnits Align = getAlignment(C);
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11.1k
    CharUnits AlignedSize = Size.alignTo(Align);
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11.1k
    if (AlignedSize > Offset || 
Offset.alignTo(Align) != Offset11.1k
)
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88
      NaturalLayout = false;
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11.1k
    else if (AlignedSize < Offset) {
151
53
      Elems.push_back(getPadding(Offset - Size));
152
53
      Offsets.push_back(Size);
153
53
    }
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11.1k
    Elems.push_back(C);
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11.1k
    Offsets.push_back(Offset);
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11.1k
    Size = Offset + getSize(C);
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11.1k
    return true;
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11.1k
  }
159
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  // Uncommon case: constant overlaps what we've already created.
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92
  llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
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92
  if (!FirstElemToReplace)
163
0
    return false;
164
165
92
  CharUnits CSize = getSize(C);
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92
  llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + CSize);
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92
  if (!LastElemToReplace)
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0
    return false;
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170
92
  assert((FirstElemToReplace == LastElemToReplace || AllowOverwrite) &&
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         "unexpectedly overwriting field");
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0
  replace(Elems, *FirstElemToReplace, *LastElemToReplace, {C});
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  replace(Offsets, *FirstElemToReplace, *LastElemToReplace, {Offset});
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92
  Size = std::max(Size, Offset + CSize);
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92
  NaturalLayout = false;
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92
  return true;
178
92
}
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bool ConstantAggregateBuilder::addBits(llvm::APInt Bits, uint64_t OffsetInBits,
181
267
                              bool AllowOverwrite) {
182
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  const ASTContext &Context = CGM.getContext();
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267
  const uint64_t CharWidth = CGM.getContext().getCharWidth();
184
185
  // Offset of where we want the first bit to go within the bits of the
186
  // current char.
187
267
  unsigned OffsetWithinChar = OffsetInBits % CharWidth;
188
189
  // We split bit-fields up into individual bytes. Walk over the bytes and
190
  // update them.
191
267
  for (CharUnits OffsetInChars =
192
267
           Context.toCharUnitsFromBits(OffsetInBits - OffsetWithinChar);
193
491
       /**/; 
++OffsetInChars224
) {
194
    // Number of bits we want to fill in this char.
195
491
    unsigned WantedBits =
196
491
        std::min((uint64_t)Bits.getBitWidth(), CharWidth - OffsetWithinChar);
197
198
    // Get a char containing the bits we want in the right places. The other
199
    // bits have unspecified values.
200
491
    llvm::APInt BitsThisChar = Bits;
201
491
    if (BitsThisChar.getBitWidth() < CharWidth)
202
239
      BitsThisChar = BitsThisChar.zext(CharWidth);
203
491
    if (CGM.getDataLayout().isBigEndian()) {
204
      // Figure out how much to shift by. We may need to left-shift if we have
205
      // less than one byte of Bits left.
206
19
      int Shift = Bits.getBitWidth() - CharWidth + OffsetWithinChar;
207
19
      if (Shift > 0)
208
10
        BitsThisChar.lshrInPlace(Shift);
209
9
      else if (Shift < 0)
210
8
        BitsThisChar = BitsThisChar.shl(-Shift);
211
472
    } else {
212
472
      BitsThisChar = BitsThisChar.shl(OffsetWithinChar);
213
472
    }
214
491
    if (BitsThisChar.getBitWidth() > CharWidth)
215
221
      BitsThisChar = BitsThisChar.trunc(CharWidth);
216
217
491
    if (WantedBits == CharWidth) {
218
      // Got a full byte: just add it directly.
219
238
      add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
220
238
          OffsetInChars, AllowOverwrite);
221
253
    } else {
222
      // Partial byte: update the existing integer if there is one. If we
223
      // can't split out a 1-CharUnit range to update, then we can't add
224
      // these bits and fail the entire constant emission.
225
253
      llvm::Optional<size_t> FirstElemToUpdate = splitAt(OffsetInChars);
226
253
      if (!FirstElemToUpdate)
227
0
        return false;
228
253
      llvm::Optional<size_t> LastElemToUpdate =
229
253
          splitAt(OffsetInChars + CharUnits::One());
230
253
      if (!LastElemToUpdate)
231
0
        return false;
232
253
      assert(*LastElemToUpdate - *FirstElemToUpdate < 2 &&
233
253
             "should have at most one element covering one byte");
234
235
      // Figure out which bits we want and discard the rest.
236
0
      llvm::APInt UpdateMask(CharWidth, 0);
237
253
      if (CGM.getDataLayout().isBigEndian())
238
8
        UpdateMask.setBits(CharWidth - OffsetWithinChar - WantedBits,
239
8
                           CharWidth - OffsetWithinChar);
240
245
      else
241
245
        UpdateMask.setBits(OffsetWithinChar, OffsetWithinChar + WantedBits);
242
253
      BitsThisChar &= UpdateMask;
243
244
253
      if (*FirstElemToUpdate == *LastElemToUpdate ||
245
253
          
Elems[*FirstElemToUpdate]->isNullValue()78
||
246
253
          
isa<llvm::UndefValue>(Elems[*FirstElemToUpdate])37
) {
247
        // All existing bits are either zero or undef.
248
218
        add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
249
218
            OffsetInChars, /*AllowOverwrite*/ true);
250
218
      } else {
251
35
        llvm::Constant *&ToUpdate = Elems[*FirstElemToUpdate];
252
        // In order to perform a partial update, we need the existing bitwise
253
        // value, which we can only extract for a constant int.
254
35
        auto *CI = dyn_cast<llvm::ConstantInt>(ToUpdate);
255
35
        if (!CI)
256
0
          return false;
257
        // Because this is a 1-CharUnit range, the constant occupying it must
258
        // be exactly one CharUnit wide.
259
35
        assert(CI->getBitWidth() == CharWidth && "splitAt failed");
260
0
        assert((!(CI->getValue() & UpdateMask) || AllowOverwrite) &&
261
35
               "unexpectedly overwriting bitfield");
262
0
        BitsThisChar |= (CI->getValue() & ~UpdateMask);
263
35
        ToUpdate = llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar);
264
35
      }
265
253
    }
266
267
    // Stop if we've added all the bits.
268
491
    if (WantedBits == Bits.getBitWidth())
269
267
      break;
270
271
    // Remove the consumed bits from Bits.
272
224
    if (!CGM.getDataLayout().isBigEndian())
273
214
      Bits.lshrInPlace(WantedBits);
274
224
    Bits = Bits.trunc(Bits.getBitWidth() - WantedBits);
275
276
    // The remanining bits go at the start of the following bytes.
277
224
    OffsetWithinChar = 0;
278
224
  }
279
280
267
  return true;
281
267
}
282
283
/// Returns a position within Elems and Offsets such that all elements
284
/// before the returned index end before Pos and all elements at or after
285
/// the returned index begin at or after Pos. Splits elements as necessary
286
/// to ensure this. Returns None if we find something we can't split.
287
726
Optional<size_t> ConstantAggregateBuilder::splitAt(CharUnits Pos) {
288
726
  if (Pos >= Size)
289
493
    return Offsets.size();
290
291
286
  
while (233
true) {
292
286
    auto FirstAfterPos = llvm::upper_bound(Offsets, Pos);
293
286
    if (FirstAfterPos == Offsets.begin())
294
0
      return 0;
295
296
    // If we already have an element starting at Pos, we're done.
297
286
    size_t LastAtOrBeforePosIndex = FirstAfterPos - Offsets.begin() - 1;
298
286
    if (Offsets[LastAtOrBeforePosIndex] == Pos)
299
229
      return LastAtOrBeforePosIndex;
300
301
    // We found an element starting before Pos. Check for overlap.
302
57
    if (Offsets[LastAtOrBeforePosIndex] +
303
57
        getSize(Elems[LastAtOrBeforePosIndex]) <= Pos)
304
4
      return LastAtOrBeforePosIndex + 1;
305
306
    // Try to decompose it into smaller constants.
307
53
    if (!split(LastAtOrBeforePosIndex, Pos))
308
0
      return None;
309
53
  }
310
233
}
311
312
/// Split the constant at index Index, if possible. Return true if we did.
313
/// Hint indicates the location at which we'd like to split, but may be
314
/// ignored.
315
53
bool ConstantAggregateBuilder::split(size_t Index, CharUnits Hint) {
316
53
  NaturalLayout = false;
317
53
  llvm::Constant *C = Elems[Index];
318
53
  CharUnits Offset = Offsets[Index];
319
320
53
  if (auto *CA = dyn_cast<llvm::ConstantAggregate>(C)) {
321
    // Expand the sequence into its contained elements.
322
    // FIXME: This assumes vector elements are byte-sized.
323
34
    replace(Elems, Index, Index + 1,
324
34
            llvm::map_range(llvm::seq(0u, CA->getNumOperands()),
325
75
                            [&](unsigned Op) { return CA->getOperand(Op); }));
326
34
    if (isa<llvm::ArrayType>(CA->getType()) ||
327
34
        
isa<llvm::VectorType>(CA->getType())32
) {
328
      // Array or vector.
329
2
      llvm::Type *ElemTy =
330
2
          llvm::GetElementPtrInst::getTypeAtIndex(CA->getType(), (uint64_t)0);
331
2
      CharUnits ElemSize = getSize(ElemTy);
332
2
      replace(
333
2
          Offsets, Index, Index + 1,
334
2
          llvm::map_range(llvm::seq(0u, CA->getNumOperands()),
335
6
                          [&](unsigned Op) { return Offset + Op * ElemSize; }));
336
32
    } else {
337
      // Must be a struct.
338
32
      auto *ST = cast<llvm::StructType>(CA->getType());
339
32
      const llvm::StructLayout *Layout =
340
32
          CGM.getDataLayout().getStructLayout(ST);
341
32
      replace(Offsets, Index, Index + 1,
342
32
              llvm::map_range(
343
69
                  llvm::seq(0u, CA->getNumOperands()), [&](unsigned Op) {
344
69
                    return Offset + CharUnits::fromQuantity(
345
69
                                        Layout->getElementOffset(Op));
346
69
                  }));
347
32
    }
348
34
    return true;
349
34
  }
350
351
19
  if (auto *CDS = dyn_cast<llvm::ConstantDataSequential>(C)) {
352
    // Expand the sequence into its contained elements.
353
    // FIXME: This assumes vector elements are byte-sized.
354
    // FIXME: If possible, split into two ConstantDataSequentials at Hint.
355
15
    CharUnits ElemSize = getSize(CDS->getElementType());
356
15
    replace(Elems, Index, Index + 1,
357
15
            llvm::map_range(llvm::seq(0u, CDS->getNumElements()),
358
87
                            [&](unsigned Elem) {
359
87
                              return CDS->getElementAsConstant(Elem);
360
87
                            }));
361
15
    replace(Offsets, Index, Index + 1,
362
15
            llvm::map_range(
363
15
                llvm::seq(0u, CDS->getNumElements()),
364
87
                [&](unsigned Elem) { return Offset + Elem * ElemSize; }));
365
15
    return true;
366
15
  }
367
368
4
  if (isa<llvm::ConstantAggregateZero>(C)) {
369
    // Split into two zeros at the hinted offset.
370
4
    CharUnits ElemSize = getSize(C);
371
4
    assert(Hint > Offset && Hint < Offset + ElemSize && "nothing to split");
372
0
    replace(Elems, Index, Index + 1,
373
4
            {getZeroes(Hint - Offset), getZeroes(Offset + ElemSize - Hint)});
374
4
    replace(Offsets, Index, Index + 1, {Offset, Hint});
375
4
    return true;
376
4
  }
377
378
0
  if (isa<llvm::UndefValue>(C)) {
379
    // Drop undef; it doesn't contribute to the final layout.
380
0
    replace(Elems, Index, Index + 1, {});
381
0
    replace(Offsets, Index, Index + 1, {});
382
0
    return true;
383
0
  }
384
385
  // FIXME: We could split a ConstantInt if the need ever arose.
386
  // We don't need to do this to handle bit-fields because we always eagerly
387
  // split them into 1-byte chunks.
388
389
0
  return false;
390
0
}
391
392
static llvm::Constant *
393
EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
394
                  llvm::Type *CommonElementType, unsigned ArrayBound,
395
                  SmallVectorImpl<llvm::Constant *> &Elements,
396
                  llvm::Constant *Filler);
397
398
llvm::Constant *ConstantAggregateBuilder::buildFrom(
399
    CodeGenModule &CGM, ArrayRef<llvm::Constant *> Elems,
400
    ArrayRef<CharUnits> Offsets, CharUnits StartOffset, CharUnits Size,
401
5.76k
    bool NaturalLayout, llvm::Type *DesiredTy, bool AllowOversized) {
402
5.76k
  ConstantAggregateBuilderUtils Utils(CGM);
403
404
5.76k
  if (Elems.empty())
405
100
    return llvm::UndefValue::get(DesiredTy);
406
407
5.66k
  auto Offset = [&](size_t I) 
{ return Offsets[I] - StartOffset; }441
;
408
409
  // If we want an array type, see if all the elements are the same type and
410
  // appropriately spaced.
411
5.66k
  if (llvm::ArrayType *ATy = dyn_cast<llvm::ArrayType>(DesiredTy)) {
412
21
    assert(!AllowOversized && "oversized array emission not supported");
413
414
0
    bool CanEmitArray = true;
415
21
    llvm::Type *CommonType = Elems[0]->getType();
416
21
    llvm::Constant *Filler = llvm::Constant::getNullValue(CommonType);
417
21
    CharUnits ElemSize = Utils.getSize(ATy->getElementType());
418
21
    SmallVector<llvm::Constant*, 32> ArrayElements;
419
128
    for (size_t I = 0; I != Elems.size(); 
++I107
) {
420
      // Skip zeroes; we'll use a zero value as our array filler.
421
109
      if (Elems[I]->isNullValue())
422
35
        continue;
423
424
      // All remaining elements must be the same type.
425
74
      if (Elems[I]->getType() != CommonType ||
426
74
          
Offset(I) % ElemSize != 072
) {
427
2
        CanEmitArray = false;
428
2
        break;
429
2
      }
430
72
      ArrayElements.resize(Offset(I) / ElemSize + 1, Filler);
431
72
      ArrayElements.back() = Elems[I];
432
72
    }
433
434
21
    if (CanEmitArray) {
435
19
      return EmitArrayConstant(CGM, ATy, CommonType, ATy->getNumElements(),
436
19
                               ArrayElements, Filler);
437
19
    }
438
439
    // Can't emit as an array, carry on to emit as a struct.
440
21
  }
441
442
  // The size of the constant we plan to generate.  This is usually just
443
  // the size of the initialized type, but in AllowOversized mode (i.e.
444
  // flexible array init), it can be larger.
445
5.64k
  CharUnits DesiredSize = Utils.getSize(DesiredTy);
446
5.64k
  if (Size > DesiredSize) {
447
14
    assert(AllowOversized && "Elems are oversized");
448
0
    DesiredSize = Size;
449
14
  }
450
451
  // The natural alignment of an unpacked LLVM struct with the given elements.
452
0
  CharUnits Align = CharUnits::One();
453
5.64k
  for (llvm::Constant *C : Elems)
454
11.2k
    Align = std::max(Align, Utils.getAlignment(C));
455
456
  // The natural size of an unpacked LLVM struct with the given elements.
457
5.64k
  CharUnits AlignedSize = Size.alignTo(Align);
458
459
5.64k
  bool Packed = false;
460
5.64k
  ArrayRef<llvm::Constant*> UnpackedElems = Elems;
461
5.64k
  llvm::SmallVector<llvm::Constant*, 32> UnpackedElemStorage;
462
5.64k
  if (DesiredSize < AlignedSize || 
DesiredSize.alignTo(Align) != DesiredSize5.54k
) {
463
    // The natural layout would be too big; force use of a packed layout.
464
97
    NaturalLayout = false;
465
97
    Packed = true;
466
5.54k
  } else if (DesiredSize > AlignedSize) {
467
    // The natural layout would be too small. Add padding to fix it. (This
468
    // is ignored if we choose a packed layout.)
469
390
    UnpackedElemStorage.assign(Elems.begin(), Elems.end());
470
390
    UnpackedElemStorage.push_back(Utils.getPadding(DesiredSize - Size));
471
390
    UnpackedElems = UnpackedElemStorage;
472
390
  }
473
474
  // If we don't have a natural layout, insert padding as necessary.
475
  // As we go, double-check to see if we can actually just emit Elems
476
  // as a non-packed struct and do so opportunistically if possible.
477
5.64k
  llvm::SmallVector<llvm::Constant*, 32> PackedElems;
478
5.64k
  if (!NaturalLayout) {
479
145
    CharUnits SizeSoFar = CharUnits::Zero();
480
442
    for (size_t I = 0; I != Elems.size(); 
++I297
) {
481
297
      CharUnits Align = Utils.getAlignment(Elems[I]);
482
297
      CharUnits NaturalOffset = SizeSoFar.alignTo(Align);
483
297
      CharUnits DesiredOffset = Offset(I);
484
297
      assert(DesiredOffset >= SizeSoFar && "elements out of order");
485
486
297
      if (DesiredOffset != NaturalOffset)
487
90
        Packed = true;
488
297
      if (DesiredOffset != SizeSoFar)
489
3
        PackedElems.push_back(Utils.getPadding(DesiredOffset - SizeSoFar));
490
297
      PackedElems.push_back(Elems[I]);
491
297
      SizeSoFar = DesiredOffset + Utils.getSize(Elems[I]);
492
297
    }
493
    // If we're using the packed layout, pad it out to the desired size if
494
    // necessary.
495
145
    if (Packed) {
496
101
      assert(SizeSoFar <= DesiredSize &&
497
101
             "requested size is too small for contents");
498
101
      if (SizeSoFar < DesiredSize)
499
10
        PackedElems.push_back(Utils.getPadding(DesiredSize - SizeSoFar));
500
101
    }
501
145
  }
502
503
0
  llvm::StructType *STy = llvm::ConstantStruct::getTypeForElements(
504
5.64k
      CGM.getLLVMContext(), Packed ? 
PackedElems101
:
UnpackedElems5.54k
, Packed);
505
506
  // Pick the type to use.  If the type is layout identical to the desired
507
  // type then use it, otherwise use whatever the builder produced for us.
508
5.64k
  if (llvm::StructType *DesiredSTy = dyn_cast<llvm::StructType>(DesiredTy)) {
509
5.63k
    if (DesiredSTy->isLayoutIdentical(STy))
510
4.71k
      STy = DesiredSTy;
511
5.63k
  }
512
513
5.64k
  return llvm::ConstantStruct::get(STy, Packed ? 
PackedElems101
:
UnpackedElems5.54k
);
514
5.66k
}
515
516
void ConstantAggregateBuilder::condense(CharUnits Offset,
517
18
                                        llvm::Type *DesiredTy) {
518
18
  CharUnits Size = getSize(DesiredTy);
519
520
18
  llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
521
18
  if (!FirstElemToReplace)
522
0
    return;
523
18
  size_t First = *FirstElemToReplace;
524
525
18
  llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + Size);
526
18
  if (!LastElemToReplace)
527
0
    return;
528
18
  size_t Last = *LastElemToReplace;
529
530
18
  size_t Length = Last - First;
531
18
  if (Length == 0)
532
0
    return;
533
534
18
  if (Length == 1 && 
Offsets[First] == Offset4
&&
535
18
      
getSize(Elems[First]) == Size4
) {
536
    // Re-wrap single element structs if necessary. Otherwise, leave any single
537
    // element constant of the right size alone even if it has the wrong type.
538
4
    auto *STy = dyn_cast<llvm::StructType>(DesiredTy);
539
4
    if (STy && STy->getNumElements() == 1 &&
540
4
        STy->getElementType(0) == Elems[First]->getType())
541
2
      Elems[First] = llvm::ConstantStruct::get(STy, Elems[First]);
542
4
    return;
543
4
  }
544
545
14
  llvm::Constant *Replacement = buildFrom(
546
14
      CGM, makeArrayRef(Elems).slice(First, Length),
547
14
      makeArrayRef(Offsets).slice(First, Length), Offset, getSize(DesiredTy),
548
14
      /*known to have natural layout=*/false, DesiredTy, false);
549
14
  replace(Elems, First, Last, {Replacement});
550
14
  replace(Offsets, First, Last, {Offset});
551
14
}
552
553
//===----------------------------------------------------------------------===//
554
//                            ConstStructBuilder
555
//===----------------------------------------------------------------------===//
556
557
class ConstStructBuilder {
558
  CodeGenModule &CGM;
559
  ConstantEmitter &Emitter;
560
  ConstantAggregateBuilder &Builder;
561
  CharUnits StartOffset;
562
563
public:
564
  static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
565
                                     InitListExpr *ILE, QualType StructTy);
566
  static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
567
                                     const APValue &Value, QualType ValTy);
568
  static bool UpdateStruct(ConstantEmitter &Emitter,
569
                           ConstantAggregateBuilder &Const, CharUnits Offset,
570
                           InitListExpr *Updater);
571
572
private:
573
  ConstStructBuilder(ConstantEmitter &Emitter,
574
                     ConstantAggregateBuilder &Builder, CharUnits StartOffset)
575
      : CGM(Emitter.CGM), Emitter(Emitter), Builder(Builder),
576
5.78k
        StartOffset(StartOffset) {}
577
578
  bool AppendField(const FieldDecl *Field, uint64_t FieldOffset,
579
                   llvm::Constant *InitExpr, bool AllowOverwrite = false);
580
581
  bool AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst,
582
                   bool AllowOverwrite = false);
583
584
  bool AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
585
                      llvm::ConstantInt *InitExpr, bool AllowOverwrite = false);
586
587
  bool Build(InitListExpr *ILE, bool AllowOverwrite);
588
  bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase,
589
             const CXXRecordDecl *VTableClass, CharUnits BaseOffset);
590
  llvm::Constant *Finalize(QualType Ty);
591
};
592
593
bool ConstStructBuilder::AppendField(
594
    const FieldDecl *Field, uint64_t FieldOffset, llvm::Constant *InitCst,
595
10.4k
    bool AllowOverwrite) {
596
10.4k
  const ASTContext &Context = CGM.getContext();
597
598
10.4k
  CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
599
600
10.4k
  return AppendBytes(FieldOffsetInChars, InitCst, AllowOverwrite);
601
10.4k
}
602
603
bool ConstStructBuilder::AppendBytes(CharUnits FieldOffsetInChars,
604
                                     llvm::Constant *InitCst,
605
10.7k
                                     bool AllowOverwrite) {
606
10.7k
  return Builder.add(InitCst, StartOffset + FieldOffsetInChars, AllowOverwrite);
607
10.7k
}
608
609
bool ConstStructBuilder::AppendBitField(
610
    const FieldDecl *Field, uint64_t FieldOffset, llvm::ConstantInt *CI,
611
267
    bool AllowOverwrite) {
612
267
  const CGRecordLayout &RL =
613
267
      CGM.getTypes().getCGRecordLayout(Field->getParent());
614
267
  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
615
267
  llvm::APInt FieldValue = CI->getValue();
616
617
  // Promote the size of FieldValue if necessary
618
  // FIXME: This should never occur, but currently it can because initializer
619
  // constants are cast to bool, and because clang is not enforcing bitfield
620
  // width limits.
621
267
  if (Info.Size > FieldValue.getBitWidth())
622
5
    FieldValue = FieldValue.zext(Info.Size);
623
624
  // Truncate the size of FieldValue to the bit field size.
625
267
  if (Info.Size < FieldValue.getBitWidth())
626
250
    FieldValue = FieldValue.trunc(Info.Size);
627
628
267
  return Builder.addBits(FieldValue,
629
267
                         CGM.getContext().toBits(StartOffset) + FieldOffset,
630
267
                         AllowOverwrite);
631
267
}
632
633
static bool EmitDesignatedInitUpdater(ConstantEmitter &Emitter,
634
                                      ConstantAggregateBuilder &Const,
635
                                      CharUnits Offset, QualType Type,
636
46
                                      InitListExpr *Updater) {
637
46
  if (Type->isRecordType())
638
25
    return ConstStructBuilder::UpdateStruct(Emitter, Const, Offset, Updater);
639
640
21
  auto CAT = Emitter.CGM.getContext().getAsConstantArrayType(Type);
641
21
  if (!CAT)
642
0
    return false;
643
21
  QualType ElemType = CAT->getElementType();
644
21
  CharUnits ElemSize = Emitter.CGM.getContext().getTypeSizeInChars(ElemType);
645
21
  llvm::Type *ElemTy = Emitter.CGM.getTypes().ConvertTypeForMem(ElemType);
646
647
21
  llvm::Constant *FillC = nullptr;
648
21
  if (Expr *Filler = Updater->getArrayFiller()) {
649
21
    if (!isa<NoInitExpr>(Filler)) {
650
3
      FillC = Emitter.tryEmitAbstractForMemory(Filler, ElemType);
651
3
      if (!FillC)
652
0
        return false;
653
3
    }
654
21
  }
655
656
21
  unsigned NumElementsToUpdate =
657
21
      FillC ? 
CAT->getSize().getZExtValue()3
:
Updater->getNumInits()18
;
658
111
  for (unsigned I = 0; I != NumElementsToUpdate; 
++I, Offset += ElemSize90
) {
659
90
    Expr *Init = nullptr;
660
90
    if (I < Updater->getNumInits())
661
78
      Init = Updater->getInit(I);
662
663
90
    if (!Init && 
FillC12
) {
664
12
      if (!Const.add(FillC, Offset, true))
665
0
        return false;
666
78
    } else if (!Init || isa<NoInitExpr>(Init)) {
667
52
      continue;
668
52
    } else 
if (InitListExpr *26
ChildILE26
= dyn_cast<InitListExpr>(Init)) {
669
4
      if (!EmitDesignatedInitUpdater(Emitter, Const, Offset, ElemType,
670
4
                                     ChildILE))
671
0
        return false;
672
      // Attempt to reduce the array element to a single constant if necessary.
673
4
      Const.condense(Offset, ElemTy);
674
22
    } else {
675
22
      llvm::Constant *Val = Emitter.tryEmitPrivateForMemory(Init, ElemType);
676
22
      if (!Const.add(Val, Offset, true))
677
0
        return false;
678
22
    }
679
90
  }
680
681
21
  return true;
682
21
}
683
684
2.34k
bool ConstStructBuilder::Build(InitListExpr *ILE, bool AllowOverwrite) {
685
2.34k
  RecordDecl *RD = ILE->getType()->castAs<RecordType>()->getDecl();
686
2.34k
  const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
687
688
2.34k
  unsigned FieldNo = -1;
689
2.34k
  unsigned ElementNo = 0;
690
691
  // Bail out if we have base classes. We could support these, but they only
692
  // arise in C++1z where we will have already constant folded most interesting
693
  // cases. FIXME: There are still a few more cases we can handle this way.
694
2.34k
  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
695
138
    if (CXXRD->getNumBases())
696
6
      return false;
697
698
5.21k
  
for (FieldDecl *Field : RD->fields())2.34k
{
699
5.21k
    ++FieldNo;
700
701
    // If this is a union, skip all the fields that aren't being initialized.
702
5.21k
    if (RD->isUnion() &&
703
5.21k
        
!declaresSameEntity(ILE->getInitializedFieldInUnion(), Field)229
)
704
107
      continue;
705
706
    // Don't emit anonymous bitfields or zero-sized fields.
707
5.10k
    if (Field->isUnnamedBitfield() || 
Field->isZeroSize(CGM.getContext())5.08k
)
708
26
      continue;
709
710
    // Get the initializer.  A struct can include fields without initializers,
711
    // we just use explicit null values for them.
712
5.08k
    Expr *Init = nullptr;
713
5.08k
    if (ElementNo < ILE->getNumInits())
714
5.03k
      Init = ILE->getInit(ElementNo++);
715
5.08k
    if (Init && 
isa<NoInitExpr>(Init)5.03k
)
716
15
      continue;
717
718
    // When emitting a DesignatedInitUpdateExpr, a nested InitListExpr
719
    // represents additional overwriting of our current constant value, and not
720
    // a new constant to emit independently.
721
5.06k
    if (AllowOverwrite &&
722
5.06k
        
(27
Field->getType()->isArrayType()27
||
Field->getType()->isRecordType()13
)) {
723
15
      if (auto *SubILE = dyn_cast<InitListExpr>(Init)) {
724
14
        CharUnits Offset = CGM.getContext().toCharUnitsFromBits(
725
14
            Layout.getFieldOffset(FieldNo));
726
14
        if (!EmitDesignatedInitUpdater(Emitter, Builder, StartOffset + Offset,
727
14
                                       Field->getType(), SubILE))
728
0
          return false;
729
        // If we split apart the field's value, try to collapse it down to a
730
        // single value now.
731
14
        Builder.condense(StartOffset + Offset,
732
14
                         CGM.getTypes().ConvertTypeForMem(Field->getType()));
733
14
        continue;
734
14
      }
735
15
    }
736
737
5.05k
    llvm::Constant *EltInit =
738
5.05k
        Init ? 
Emitter.tryEmitPrivateForMemory(Init, Field->getType())5.00k
739
5.05k
             : 
Emitter.emitNullForMemory(Field->getType())46
;
740
5.05k
    if (!EltInit)
741
32
      return false;
742
743
5.02k
    if (!Field->isBitField()) {
744
      // Handle non-bitfield members.
745
4.87k
      if (!AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit,
746
4.87k
                       AllowOverwrite))
747
0
        return false;
748
      // After emitting a non-empty field with [[no_unique_address]], we may
749
      // need to overwrite its tail padding.
750
4.87k
      if (Field->hasAttr<NoUniqueAddressAttr>())
751
0
        AllowOverwrite = true;
752
4.87k
    } else {
753
      // Otherwise we have a bitfield.
754
144
      if (auto *CI = dyn_cast<llvm::ConstantInt>(EltInit)) {
755
141
        if (!AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI,
756
141
                            AllowOverwrite))
757
0
          return false;
758
141
      } else {
759
        // We are trying to initialize a bitfield with a non-trivial constant,
760
        // this must require run-time code.
761
3
        return false;
762
3
      }
763
144
    }
764
5.02k
  }
765
766
2.30k
  return true;
767
2.34k
}
768
769
namespace {
770
struct BaseInfo {
771
  BaseInfo(const CXXRecordDecl *Decl, CharUnits Offset, unsigned Index)
772
418
    : Decl(Decl), Offset(Offset), Index(Index) {
773
418
  }
774
775
  const CXXRecordDecl *Decl;
776
  CharUnits Offset;
777
  unsigned Index;
778
779
63
  bool operator<(const BaseInfo &O) const { return Offset < O.Offset; }
780
};
781
}
782
783
bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
784
                               bool IsPrimaryBase,
785
                               const CXXRecordDecl *VTableClass,
786
3.85k
                               CharUnits Offset) {
787
3.85k
  const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
788
789
3.85k
  if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
790
    // Add a vtable pointer, if we need one and it hasn't already been added.
791
3.85k
    if (Layout.hasOwnVFPtr()) {
792
346
      llvm::Constant *VTableAddressPoint =
793
346
          CGM.getCXXABI().getVTableAddressPointForConstExpr(
794
346
              BaseSubobject(CD, Offset), VTableClass);
795
346
      if (!AppendBytes(Offset, VTableAddressPoint))
796
0
        return false;
797
346
    }
798
799
    // Accumulate and sort bases, in order to visit them in address order, which
800
    // may not be the same as declaration order.
801
3.85k
    SmallVector<BaseInfo, 8> Bases;
802
3.85k
    Bases.reserve(CD->getNumBases());
803
3.85k
    unsigned BaseNo = 0;
804
3.85k
    for (CXXRecordDecl::base_class_const_iterator Base = CD->bases_begin(),
805
4.27k
         BaseEnd = CD->bases_end(); Base != BaseEnd; 
++Base, ++BaseNo418
) {
806
418
      assert(!Base->isVirtual() && "should not have virtual bases here");
807
0
      const CXXRecordDecl *BD = Base->getType()->getAsCXXRecordDecl();
808
418
      CharUnits BaseOffset = Layout.getBaseClassOffset(BD);
809
418
      Bases.push_back(BaseInfo(BD, BaseOffset, BaseNo));
810
418
    }
811
3.85k
    llvm::stable_sort(Bases);
812
813
4.27k
    for (unsigned I = 0, N = Bases.size(); I != N; 
++I418
) {
814
418
      BaseInfo &Base = Bases[I];
815
816
418
      bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl;
817
418
      Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
818
418
            VTableClass, Offset + Base.Offset);
819
418
    }
820
3.85k
  }
821
822
3.85k
  unsigned FieldNo = 0;
823
3.85k
  uint64_t OffsetBits = CGM.getContext().toBits(Offset);
824
825
3.85k
  bool AllowOverwrite = false;
826
3.85k
  for (RecordDecl::field_iterator Field = RD->field_begin(),
827
10.0k
       FieldEnd = RD->field_end(); Field != FieldEnd; 
++Field, ++FieldNo6.14k
) {
828
    // If this is a union, skip all the fields that aren't being initialized.
829
6.14k
    if (RD->isUnion() && 
!declaresSameEntity(Val.getUnionField(), *Field)913
)
830
434
      continue;
831
832
    // Don't emit anonymous bitfields or zero-sized fields.
833
5.71k
    if (Field->isUnnamedBitfield() || 
Field->isZeroSize(CGM.getContext())5.69k
)
834
39
      continue;
835
836
    // Emit the value of the initializer.
837
5.67k
    const APValue &FieldValue =
838
5.67k
      RD->isUnion() ? 
Val.getUnionValue()479
:
Val.getStructField(FieldNo)5.19k
;
839
5.67k
    llvm::Constant *EltInit =
840
5.67k
      Emitter.tryEmitPrivateForMemory(FieldValue, Field->getType());
841
5.67k
    if (!EltInit)
842
0
      return false;
843
844
5.67k
    if (!Field->isBitField()) {
845
      // Handle non-bitfield members.
846
5.54k
      if (!AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
847
5.54k
                       EltInit, AllowOverwrite))
848
0
        return false;
849
      // After emitting a non-empty field with [[no_unique_address]], we may
850
      // need to overwrite its tail padding.
851
5.54k
      if (Field->hasAttr<NoUniqueAddressAttr>())
852
6
        AllowOverwrite = true;
853
5.54k
    } else {
854
      // Otherwise we have a bitfield.
855
126
      if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
856
126
                          cast<llvm::ConstantInt>(EltInit), AllowOverwrite))
857
0
        return false;
858
126
    }
859
5.67k
  }
860
861
3.85k
  return true;
862
3.85k
}
863
864
5.71k
llvm::Constant *ConstStructBuilder::Finalize(QualType Type) {
865
5.71k
  Type = Type.getNonReferenceType();
866
5.71k
  RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
867
5.71k
  llvm::Type *ValTy = CGM.getTypes().ConvertType(Type);
868
5.71k
  return Builder.build(ValTy, RD->hasFlexibleArrayMember());
869
5.71k
}
870
871
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
872
                                                InitListExpr *ILE,
873
2.32k
                                                QualType ValTy) {
874
2.32k
  ConstantAggregateBuilder Const(Emitter.CGM);
875
2.32k
  ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
876
877
2.32k
  if (!Builder.Build(ILE, /*AllowOverwrite*/false))
878
41
    return nullptr;
879
880
2.28k
  return Builder.Finalize(ValTy);
881
2.32k
}
882
883
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
884
                                                const APValue &Val,
885
3.43k
                                                QualType ValTy) {
886
3.43k
  ConstantAggregateBuilder Const(Emitter.CGM);
887
3.43k
  ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
888
889
3.43k
  const RecordDecl *RD = ValTy->castAs<RecordType>()->getDecl();
890
3.43k
  const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
891
3.43k
  if (!Builder.Build(Val, RD, false, CD, CharUnits::Zero()))
892
0
    return nullptr;
893
894
3.43k
  return Builder.Finalize(ValTy);
895
3.43k
}
896
897
bool ConstStructBuilder::UpdateStruct(ConstantEmitter &Emitter,
898
                                      ConstantAggregateBuilder &Const,
899
25
                                      CharUnits Offset, InitListExpr *Updater) {
900
25
  return ConstStructBuilder(Emitter, Const, Offset)
901
25
      .Build(Updater, /*AllowOverwrite*/ true);
902
25
}
903
904
//===----------------------------------------------------------------------===//
905
//                             ConstExprEmitter
906
//===----------------------------------------------------------------------===//
907
908
static ConstantAddress tryEmitGlobalCompoundLiteral(CodeGenModule &CGM,
909
                                                    CodeGenFunction *CGF,
910
23
                                              const CompoundLiteralExpr *E) {
911
23
  CharUnits Align = CGM.getContext().getTypeAlignInChars(E->getType());
912
23
  if (llvm::GlobalVariable *Addr =
913
23
          CGM.getAddrOfConstantCompoundLiteralIfEmitted(E))
914
2
    return ConstantAddress(Addr, Addr->getValueType(), Align);
915
916
21
  LangAS addressSpace = E->getType().getAddressSpace();
917
918
21
  ConstantEmitter emitter(CGM, CGF);
919
21
  llvm::Constant *C = emitter.tryEmitForInitializer(E->getInitializer(),
920
21
                                                    addressSpace, E->getType());
921
21
  if (!C) {
922
0
    assert(!E->isFileScope() &&
923
0
           "file-scope compound literal did not have constant initializer!");
924
0
    return ConstantAddress::invalid();
925
0
  }
926
927
21
  auto GV = new llvm::GlobalVariable(CGM.getModule(), C->getType(),
928
21
                                     CGM.isTypeConstant(E->getType(), true),
929
21
                                     llvm::GlobalValue::InternalLinkage,
930
21
                                     C, ".compoundliteral", nullptr,
931
21
                                     llvm::GlobalVariable::NotThreadLocal,
932
21
                    CGM.getContext().getTargetAddressSpace(addressSpace));
933
21
  emitter.finalize(GV);
934
21
  GV->setAlignment(Align.getAsAlign());
935
21
  CGM.setAddrOfConstantCompoundLiteral(E, GV);
936
21
  return ConstantAddress(GV, GV->getValueType(), Align);
937
21
}
938
939
static llvm::Constant *
940
EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
941
                  llvm::Type *CommonElementType, unsigned ArrayBound,
942
                  SmallVectorImpl<llvm::Constant *> &Elements,
943
3.82k
                  llvm::Constant *Filler) {
944
  // Figure out how long the initial prefix of non-zero elements is.
945
3.82k
  unsigned NonzeroLength = ArrayBound;
946
3.82k
  if (Elements.size() < NonzeroLength && 
Filler->isNullValue()839
)
947
831
    NonzeroLength = Elements.size();
948
3.82k
  if (NonzeroLength == Elements.size()) {
949
4.37k
    while (NonzeroLength > 0 && 
Elements[NonzeroLength - 1]->isNullValue()3.73k
)
950
561
      --NonzeroLength;
951
3.81k
  }
952
953
3.82k
  if (NonzeroLength == 0)
954
639
    return llvm::ConstantAggregateZero::get(DesiredType);
955
956
  // Add a zeroinitializer array filler if we have lots of trailing zeroes.
957
3.18k
  unsigned TrailingZeroes = ArrayBound - NonzeroLength;
958
3.18k
  if (TrailingZeroes >= 8) {
959
64
    assert(Elements.size() >= NonzeroLength &&
960
64
           "missing initializer for non-zero element");
961
962
    // If all the elements had the same type up to the trailing zeroes, emit a
963
    // struct of two arrays (the nonzero data and the zeroinitializer).
964
64
    if (CommonElementType && 
NonzeroLength >= 862
) {
965
18
      llvm::Constant *Initial = llvm::ConstantArray::get(
966
18
          llvm::ArrayType::get(CommonElementType, NonzeroLength),
967
18
          makeArrayRef(Elements).take_front(NonzeroLength));
968
18
      Elements.resize(2);
969
18
      Elements[0] = Initial;
970
46
    } else {
971
46
      Elements.resize(NonzeroLength + 1);
972
46
    }
973
974
64
    auto *FillerType =
975
64
        CommonElementType ? 
CommonElementType62
:
DesiredType->getElementType()2
;
976
64
    FillerType = llvm::ArrayType::get(FillerType, TrailingZeroes);
977
64
    Elements.back() = llvm::ConstantAggregateZero::get(FillerType);
978
64
    CommonElementType = nullptr;
979
3.11k
  } else if (Elements.size() != ArrayBound) {
980
    // Otherwise pad to the right size with the filler if necessary.
981
236
    Elements.resize(ArrayBound, Filler);
982
236
    if (Filler->getType() != CommonElementType)
983
8
      CommonElementType = nullptr;
984
236
  }
985
986
  // If all elements have the same type, just emit an array constant.
987
3.18k
  if (CommonElementType)
988
3.10k
    return llvm::ConstantArray::get(
989
3.10k
        llvm::ArrayType::get(CommonElementType, ArrayBound), Elements);
990
991
  // We have mixed types. Use a packed struct.
992
77
  llvm::SmallVector<llvm::Type *, 16> Types;
993
77
  Types.reserve(Elements.size());
994
77
  for (llvm::Constant *Elt : Elements)
995
245
    Types.push_back(Elt->getType());
996
77
  llvm::StructType *SType =
997
77
      llvm::StructType::get(CGM.getLLVMContext(), Types, true);
998
77
  return llvm::ConstantStruct::get(SType, Elements);
999
3.18k
}
1000
1001
// This class only needs to handle arrays, structs and unions. Outside C++11
1002
// mode, we don't currently constant fold those types.  All other types are
1003
// handled by constant folding.
1004
//
1005
// Constant folding is currently missing support for a few features supported
1006
// here: CK_ToUnion, CK_ReinterpretMemberPointer, and DesignatedInitUpdateExpr.
1007
class ConstExprEmitter :
1008
  public StmtVisitor<ConstExprEmitter, llvm::Constant*, QualType> {
1009
  CodeGenModule &CGM;
1010
  ConstantEmitter &Emitter;
1011
  llvm::LLVMContext &VMContext;
1012
public:
1013
  ConstExprEmitter(ConstantEmitter &emitter)
1014
29.6k
    : CGM(emitter.CGM), Emitter(emitter), VMContext(CGM.getLLVMContext()) {
1015
29.6k
  }
1016
1017
  //===--------------------------------------------------------------------===//
1018
  //                            Visitor Methods
1019
  //===--------------------------------------------------------------------===//
1020
1021
13.2k
  llvm::Constant *VisitStmt(Stmt *S, QualType T) {
1022
13.2k
    return nullptr;
1023
13.2k
  }
1024
1025
18
  llvm::Constant *VisitConstantExpr(ConstantExpr *CE, QualType T) {
1026
18
    if (llvm::Constant *Result = Emitter.tryEmitConstantExpr(CE))
1027
0
      return Result;
1028
18
    return Visit(CE->getSubExpr(), T);
1029
18
  }
1030
1031
28
  llvm::Constant *VisitParenExpr(ParenExpr *PE, QualType T) {
1032
28
    return Visit(PE->getSubExpr(), T);
1033
28
  }
1034
1035
  llvm::Constant *
1036
  VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *PE,
1037
0
                                    QualType T) {
1038
0
    return Visit(PE->getReplacement(), T);
1039
0
  }
1040
1041
  llvm::Constant *VisitGenericSelectionExpr(GenericSelectionExpr *GE,
1042
1
                                            QualType T) {
1043
1
    return Visit(GE->getResultExpr(), T);
1044
1
  }
1045
1046
1
  llvm::Constant *VisitChooseExpr(ChooseExpr *CE, QualType T) {
1047
1
    return Visit(CE->getChosenSubExpr(), T);
1048
1
  }
1049
1050
16
  llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E, QualType T) {
1051
16
    return Visit(E->getInitializer(), T);
1052
16
  }
1053
1054
8.38k
  llvm::Constant *VisitCastExpr(CastExpr *E, QualType destType) {
1055
8.38k
    if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
1056
392
      CGM.EmitExplicitCastExprType(ECE, Emitter.CGF);
1057
8.38k
    Expr *subExpr = E->getSubExpr();
1058
1059
8.38k
    switch (E->getCastKind()) {
1060
4
    case CK_ToUnion: {
1061
      // GCC cast to union extension
1062
4
      assert(E->getType()->isUnionType() &&
1063
4
             "Destination type is not union type!");
1064
1065
0
      auto field = E->getTargetUnionField();
1066
1067
4
      auto C = Emitter.tryEmitPrivateForMemory(subExpr, field->getType());
1068
4
      if (!C) 
return nullptr0
;
1069
1070
4
      auto destTy = ConvertType(destType);
1071
4
      if (C->getType() == destTy) 
return C0
;
1072
1073
      // Build a struct with the union sub-element as the first member,
1074
      // and padded to the appropriate size.
1075
4
      SmallVector<llvm::Constant*, 2> Elts;
1076
4
      SmallVector<llvm::Type*, 2> Types;
1077
4
      Elts.push_back(C);
1078
4
      Types.push_back(C->getType());
1079
4
      unsigned CurSize = CGM.getDataLayout().getTypeAllocSize(C->getType());
1080
4
      unsigned TotalSize = CGM.getDataLayout().getTypeAllocSize(destTy);
1081
1082
4
      assert(CurSize <= TotalSize && "Union size mismatch!");
1083
4
      if (unsigned NumPadBytes = TotalSize - CurSize) {
1084
2
        llvm::Type *Ty = CGM.CharTy;
1085
2
        if (NumPadBytes > 1)
1086
2
          Ty = llvm::ArrayType::get(Ty, NumPadBytes);
1087
1088
2
        Elts.push_back(llvm::UndefValue::get(Ty));
1089
2
        Types.push_back(Ty);
1090
2
      }
1091
1092
4
      llvm::StructType *STy = llvm::StructType::get(VMContext, Types, false);
1093
4
      return llvm::ConstantStruct::get(STy, Elts);
1094
4
    }
1095
1096
0
    case CK_AddressSpaceConversion: {
1097
0
      auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
1098
0
      if (!C) return nullptr;
1099
0
      LangAS destAS = E->getType()->getPointeeType().getAddressSpace();
1100
0
      LangAS srcAS = subExpr->getType()->getPointeeType().getAddressSpace();
1101
0
      llvm::Type *destTy = ConvertType(E->getType());
1102
0
      return CGM.getTargetCodeGenInfo().performAddrSpaceCast(CGM, C, srcAS,
1103
0
                                                             destAS, destTy);
1104
0
    }
1105
1106
7.49k
    case CK_LValueToRValue: {
1107
      // We don't really support doing lvalue-to-rvalue conversions here; any
1108
      // interesting conversions should be done in Evaluate().  But as a
1109
      // special case, allow compound literals to support the gcc extension
1110
      // allowing "struct x {int x;} x = (struct x) {};".
1111
7.49k
      if (auto *E = dyn_cast<CompoundLiteralExpr>(subExpr->IgnoreParens()))
1112
22
        return Visit(E->getInitializer(), destType);
1113
7.47k
      return nullptr;
1114
7.49k
    }
1115
1116
0
    case CK_AtomicToNonAtomic:
1117
4
    case CK_NonAtomicToAtomic:
1118
414
    case CK_NoOp:
1119
442
    case CK_ConstructorConversion:
1120
442
      return Visit(subExpr, destType);
1121
1122
0
    case CK_IntToOCLSampler:
1123
0
      llvm_unreachable("global sampler variables are not generated");
1124
1125
0
    case CK_Dependent: llvm_unreachable("saw dependent cast!");
1126
1127
0
    case CK_BuiltinFnToFnPtr:
1128
0
      llvm_unreachable("builtin functions are handled elsewhere");
1129
1130
39
    case CK_ReinterpretMemberPointer:
1131
41
    case CK_DerivedToBaseMemberPointer:
1132
52
    case CK_BaseToDerivedMemberPointer: {
1133
52
      auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
1134
52
      if (!C) 
return nullptr0
;
1135
52
      return CGM.getCXXABI().EmitMemberPointerConversion(E, C);
1136
52
    }
1137
1138
    // These will never be supported.
1139
0
    case CK_ObjCObjectLValueCast:
1140
0
    case CK_ARCProduceObject:
1141
3
    case CK_ARCConsumeObject:
1142
34
    case CK_ARCReclaimReturnedObject:
1143
34
    case CK_ARCExtendBlockObject:
1144
34
    case CK_CopyAndAutoreleaseBlockObject:
1145
34
      return nullptr;
1146
1147
    // These don't need to be handled here because Evaluate knows how to
1148
    // evaluate them in the cases where they can be folded.
1149
70
    case CK_BitCast:
1150
70
    case CK_ToVoid:
1151
70
    case CK_Dynamic:
1152
70
    case CK_LValueBitCast:
1153
70
    case CK_LValueToRValueBitCast:
1154
71
    case CK_NullToMemberPointer:
1155
120
    case CK_UserDefinedConversion:
1156
123
    case CK_CPointerToObjCPointerCast:
1157
123
    case CK_BlockPointerToObjCPointerCast:
1158
123
    case CK_AnyPointerToBlockPointerCast:
1159
125
    case CK_ArrayToPointerDecay:
1160
125
    case CK_FunctionToPointerDecay:
1161
125
    case CK_BaseToDerived:
1162
137
    case CK_DerivedToBase:
1163
137
    case CK_UncheckedDerivedToBase:
1164
137
    case CK_MemberPointerToBoolean:
1165
137
    case CK_VectorSplat:
1166
137
    case CK_FloatingRealToComplex:
1167
137
    case CK_FloatingComplexToReal:
1168
137
    case CK_FloatingComplexToBoolean:
1169
137
    case CK_FloatingComplexCast:
1170
137
    case CK_FloatingComplexToIntegralComplex:
1171
137
    case CK_IntegralRealToComplex:
1172
137
    case CK_IntegralComplexToReal:
1173
137
    case CK_IntegralComplexToBoolean:
1174
137
    case CK_IntegralComplexCast:
1175
137
    case CK_IntegralComplexToFloatingComplex:
1176
142
    case CK_PointerToIntegral:
1177
142
    case CK_PointerToBoolean:
1178
144
    case CK_NullToPointer:
1179
347
    case CK_IntegralCast:
1180
347
    case CK_BooleanToSignedIntegral:
1181
350
    case CK_IntegralToPointer:
1182
350
    case CK_IntegralToBoolean:
1183
355
    case CK_IntegralToFloating:
1184
357
    case CK_FloatingToIntegral:
1185
357
    case CK_FloatingToBoolean:
1186
357
    case CK_FloatingCast:
1187
357
    case CK_FloatingToFixedPoint:
1188
357
    case CK_FixedPointToFloating:
1189
357
    case CK_FixedPointCast:
1190
357
    case CK_FixedPointToBoolean:
1191
357
    case CK_FixedPointToIntegral:
1192
357
    case CK_IntegralToFixedPoint:
1193
357
    case CK_ZeroToOCLOpaqueType:
1194
357
    case CK_MatrixCast:
1195
357
      return nullptr;
1196
8.38k
    }
1197
0
    llvm_unreachable("Invalid CastKind");
1198
0
  }
1199
1200
4
  llvm::Constant *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE, QualType T) {
1201
    // No need for a DefaultInitExprScope: we don't handle 'this' in a
1202
    // constant expression.
1203
4
    return Visit(DIE->getExpr(), T);
1204
4
  }
1205
1206
693
  llvm::Constant *VisitExprWithCleanups(ExprWithCleanups *E, QualType T) {
1207
693
    return Visit(E->getSubExpr(), T);
1208
693
  }
1209
1210
  llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
1211
175
                                                QualType T) {
1212
175
    return Visit(E->getSubExpr(), T);
1213
175
  }
1214
1215
1.11k
  llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) {
1216
1.11k
    auto *CAT = CGM.getContext().getAsConstantArrayType(ILE->getType());
1217
1.11k
    assert(CAT && "can't emit array init for non-constant-bound array");
1218
0
    unsigned NumInitElements = ILE->getNumInits();
1219
1.11k
    unsigned NumElements = CAT->getSize().getZExtValue();
1220
1221
    // Initialising an array requires us to automatically
1222
    // initialise any elements that have not been initialised explicitly
1223
1.11k
    unsigned NumInitableElts = std::min(NumInitElements, NumElements);
1224
1225
1.11k
    QualType EltType = CAT->getElementType();
1226
1227
    // Initialize remaining array elements.
1228
1.11k
    llvm::Constant *fillC = nullptr;
1229
1.11k
    if (Expr *filler = ILE->getArrayFiller()) {
1230
153
      fillC = Emitter.tryEmitAbstractForMemory(filler, EltType);
1231
153
      if (!fillC)
1232
11
        return nullptr;
1233
153
    }
1234
1235
    // Copy initializer elements.
1236
1.10k
    SmallVector<llvm::Constant*, 16> Elts;
1237
1.10k
    if (fillC && 
fillC->isNullValue()142
)
1238
142
      Elts.reserve(NumInitableElts + 1);
1239
960
    else
1240
960
      Elts.reserve(NumElements);
1241
1242
1.10k
    llvm::Type *CommonElementType = nullptr;
1243
6.48k
    for (unsigned i = 0; i < NumInitableElts; 
++i5.37k
) {
1244
5.76k
      Expr *Init = ILE->getInit(i);
1245
5.76k
      llvm::Constant *C = Emitter.tryEmitPrivateForMemory(Init, EltType);
1246
5.76k
      if (!C)
1247
387
        return nullptr;
1248
5.37k
      if (i == 0)
1249
697
        CommonElementType = C->getType();
1250
4.68k
      else if (C->getType() != CommonElementType)
1251
4
        CommonElementType = nullptr;
1252
5.37k
      Elts.push_back(C);
1253
5.37k
    }
1254
1255
715
    llvm::ArrayType *Desired =
1256
715
        cast<llvm::ArrayType>(CGM.getTypes().ConvertType(ILE->getType()));
1257
715
    return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
1258
715
                             fillC);
1259
1.10k
  }
1260
1261
2.32k
  llvm::Constant *EmitRecordInitialization(InitListExpr *ILE, QualType T) {
1262
2.32k
    return ConstStructBuilder::BuildStruct(Emitter, ILE, T);
1263
2.32k
  }
1264
1265
  llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E,
1266
54
                                             QualType T) {
1267
54
    return CGM.EmitNullConstant(T);
1268
54
  }
1269
1270
3.45k
  llvm::Constant *VisitInitListExpr(InitListExpr *ILE, QualType T) {
1271
3.45k
    if (ILE->isTransparent())
1272
18
      return Visit(ILE->getInit(0), T);
1273
1274
3.43k
    if (ILE->getType()->isArrayType())
1275
1.11k
      return EmitArrayInitialization(ILE, T);
1276
1277
2.32k
    if (ILE->getType()->isRecordType())
1278
2.32k
      return EmitRecordInitialization(ILE, T);
1279
1280
0
    return nullptr;
1281
2.32k
  }
1282
1283
  llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E,
1284
28
                                                QualType destType) {
1285
28
    auto C = Visit(E->getBase(), destType);
1286
28
    if (!C)
1287
0
      return nullptr;
1288
1289
28
    ConstantAggregateBuilder Const(CGM);
1290
28
    Const.add(C, CharUnits::Zero(), false);
1291
1292
28
    if (!EmitDesignatedInitUpdater(Emitter, Const, CharUnits::Zero(), destType,
1293
28
                                   E->getUpdater()))
1294
0
      return nullptr;
1295
1296
28
    llvm::Type *ValTy = CGM.getTypes().ConvertType(destType);
1297
28
    bool HasFlexibleArray = false;
1298
28
    if (auto *RT = destType->getAs<RecordType>())
1299
20
      HasFlexibleArray = RT->getDecl()->hasFlexibleArrayMember();
1300
28
    return Const.build(ValTy, HasFlexibleArray);
1301
28
  }
1302
1303
5.02k
  llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) {
1304
5.02k
    if (!E->getConstructor()->isTrivial())
1305
4.80k
      return nullptr;
1306
1307
    // Only default and copy/move constructors can be trivial.
1308
222
    if (E->getNumArgs()) {
1309
220
      assert(E->getNumArgs() == 1 && "trivial ctor with > 1 argument");
1310
0
      assert(E->getConstructor()->isCopyOrMoveConstructor() &&
1311
220
             "trivial ctor has argument but isn't a copy/move ctor");
1312
1313
0
      Expr *Arg = E->getArg(0);
1314
220
      assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) &&
1315
220
             "argument to copy ctor is of wrong type");
1316
1317
0
      return Visit(Arg, Ty);
1318
220
    }
1319
1320
2
    return CGM.EmitNullConstant(Ty);
1321
222
  }
1322
1323
99
  llvm::Constant *VisitStringLiteral(StringLiteral *E, QualType T) {
1324
    // This is a string literal initializing an array in an initializer.
1325
99
    return CGM.GetConstantArrayFromStringLiteral(E);
1326
99
  }
1327
1328
64
  llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E, QualType T) {
1329
    // This must be an @encode initializing an array in a static initializer.
1330
    // Don't emit it as the address of the string, emit the string data itself
1331
    // as an inline array.
1332
64
    std::string Str;
1333
64
    CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str);
1334
64
    const ConstantArrayType *CAT = CGM.getContext().getAsConstantArrayType(T);
1335
1336
    // Resize the string to the right size, adding zeros at the end, or
1337
    // truncating as needed.
1338
64
    Str.resize(CAT->getSize().getZExtValue(), '\0');
1339
64
    return llvm::ConstantDataArray::getString(VMContext, Str, false);
1340
64
  }
1341
1342
1
  llvm::Constant *VisitUnaryExtension(const UnaryOperator *E, QualType T) {
1343
1
    return Visit(E->getSubExpr(), T);
1344
1
  }
1345
1346
  // Utility methods
1347
4
  llvm::Type *ConvertType(QualType T) {
1348
4
    return CGM.getTypes().ConvertType(T);
1349
4
  }
1350
};
1351
1352
}  // end anonymous namespace.
1353
1354
llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C,
1355
28.7k
                                                        AbstractState saved) {
1356
28.7k
  Abstract = saved.OldValue;
1357
1358
28.7k
  assert(saved.OldPlaceholdersSize == PlaceholderAddresses.size() &&
1359
28.7k
         "created a placeholder while doing an abstract emission?");
1360
1361
  // No validation necessary for now.
1362
  // No cleanup to do for now.
1363
0
  return C;
1364
28.7k
}
1365
1366
llvm::Constant *
1367
19.9k
ConstantEmitter::tryEmitAbstractForInitializer(const VarDecl &D) {
1368
19.9k
  auto state = pushAbstract();
1369
19.9k
  auto C = tryEmitPrivateForVarInit(D);
1370
19.9k
  return validateAndPopAbstract(C, state);
1371
19.9k
}
1372
1373
llvm::Constant *
1374
577
ConstantEmitter::tryEmitAbstract(const Expr *E, QualType destType) {
1375
577
  auto state = pushAbstract();
1376
577
  auto C = tryEmitPrivate(E, destType);
1377
577
  return validateAndPopAbstract(C, state);
1378
577
}
1379
1380
llvm::Constant *
1381
690
ConstantEmitter::tryEmitAbstract(const APValue &value, QualType destType) {
1382
690
  auto state = pushAbstract();
1383
690
  auto C = tryEmitPrivate(value, destType);
1384
690
  return validateAndPopAbstract(C, state);
1385
690
}
1386
1387
590
llvm::Constant *ConstantEmitter::tryEmitConstantExpr(const ConstantExpr *CE) {
1388
590
  if (!CE->hasAPValueResult())
1389
19
    return nullptr;
1390
571
  const Expr *Inner = CE->getSubExpr()->IgnoreImplicit();
1391
571
  QualType RetType;
1392
571
  if (auto *Call = dyn_cast<CallExpr>(Inner))
1393
17
    RetType = Call->getCallReturnType(CGM.getContext());
1394
554
  else if (auto *Ctor = dyn_cast<CXXConstructExpr>(Inner))
1395
1
    RetType = Ctor->getType();
1396
571
  llvm::Constant *Res =
1397
571
      emitAbstract(CE->getBeginLoc(), CE->getAPValueResult(), RetType);
1398
571
  return Res;
1399
590
}
1400
1401
llvm::Constant *
1402
283
ConstantEmitter::emitAbstract(const Expr *E, QualType destType) {
1403
283
  auto state = pushAbstract();
1404
283
  auto C = tryEmitPrivate(E, destType);
1405
283
  C = validateAndPopAbstract(C, state);
1406
283
  if (!C) {
1407
0
    CGM.Error(E->getExprLoc(),
1408
0
              "internal error: could not emit constant value \"abstractly\"");
1409
0
    C = CGM.EmitNullConstant(destType);
1410
0
  }
1411
283
  return C;
1412
283
}
1413
1414
llvm::Constant *
1415
ConstantEmitter::emitAbstract(SourceLocation loc, const APValue &value,
1416
7.22k
                              QualType destType) {
1417
7.22k
  auto state = pushAbstract();
1418
7.22k
  auto C = tryEmitPrivate(value, destType);
1419
7.22k
  C = validateAndPopAbstract(C, state);
1420
7.22k
  if (!C) {
1421
0
    CGM.Error(loc,
1422
0
              "internal error: could not emit constant value \"abstractly\"");
1423
0
    C = CGM.EmitNullConstant(destType);
1424
0
  }
1425
7.22k
  return C;
1426
7.22k
}
1427
1428
26.6k
llvm::Constant *ConstantEmitter::tryEmitForInitializer(const VarDecl &D) {
1429
26.6k
  initializeNonAbstract(D.getType().getAddressSpace());
1430
26.6k
  return markIfFailed(tryEmitPrivateForVarInit(D));
1431
26.6k
}
1432
1433
llvm::Constant *ConstantEmitter::tryEmitForInitializer(const Expr *E,
1434
                                                       LangAS destAddrSpace,
1435
108
                                                       QualType destType) {
1436
108
  initializeNonAbstract(destAddrSpace);
1437
108
  return markIfFailed(tryEmitPrivateForMemory(E, destType));
1438
108
}
1439
1440
llvm::Constant *ConstantEmitter::emitForInitializer(const APValue &value,
1441
                                                    LangAS destAddrSpace,
1442
196
                                                    QualType destType) {
1443
196
  initializeNonAbstract(destAddrSpace);
1444
196
  auto C = tryEmitPrivateForMemory(value, destType);
1445
196
  assert(C && "couldn't emit constant value non-abstractly?");
1446
0
  return C;
1447
196
}
1448
1449
0
llvm::GlobalValue *ConstantEmitter::getCurrentAddrPrivate() {
1450
0
  assert(!Abstract && "cannot get current address for abstract constant");
1451
1452
1453
1454
  // Make an obviously ill-formed global that should blow up compilation
1455
  // if it survives.
1456
0
  auto global = new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty, true,
1457
0
                                         llvm::GlobalValue::PrivateLinkage,
1458
0
                                         /*init*/ nullptr,
1459
0
                                         /*name*/ "",
1460
0
                                         /*before*/ nullptr,
1461
0
                                         llvm::GlobalVariable::NotThreadLocal,
1462
0
                                         CGM.getContext().getTargetAddressSpace(DestAddressSpace));
1463
1464
0
  PlaceholderAddresses.push_back(std::make_pair(nullptr, global));
1465
1466
0
  return global;
1467
0
}
1468
1469
void ConstantEmitter::registerCurrentAddrPrivate(llvm::Constant *signal,
1470
0
                                           llvm::GlobalValue *placeholder) {
1471
0
  assert(!PlaceholderAddresses.empty());
1472
0
  assert(PlaceholderAddresses.back().first == nullptr);
1473
0
  assert(PlaceholderAddresses.back().second == placeholder);
1474
0
  PlaceholderAddresses.back().first = signal;
1475
0
}
1476
1477
namespace {
1478
  struct ReplacePlaceholders {
1479
    CodeGenModule &CGM;
1480
1481
    /// The base address of the global.
1482
    llvm::Constant *Base;
1483
    llvm::Type *BaseValueTy = nullptr;
1484
1485
    /// The placeholder addresses that were registered during emission.
1486
    llvm::DenseMap<llvm::Constant*, llvm::GlobalVariable*> PlaceholderAddresses;
1487
1488
    /// The locations of the placeholder signals.
1489
    llvm::DenseMap<llvm::GlobalVariable*, llvm::Constant*> Locations;
1490
1491
    /// The current index stack.  We use a simple unsigned stack because
1492
    /// we assume that placeholders will be relatively sparse in the
1493
    /// initializer, but we cache the index values we find just in case.
1494
    llvm::SmallVector<unsigned, 8> Indices;
1495
    llvm::SmallVector<llvm::Constant*, 8> IndexValues;
1496
1497
    ReplacePlaceholders(CodeGenModule &CGM, llvm::Constant *base,
1498
                        ArrayRef<std::pair<llvm::Constant*,
1499
                                           llvm::GlobalVariable*>> addresses)
1500
        : CGM(CGM), Base(base),
1501
0
          PlaceholderAddresses(addresses.begin(), addresses.end()) {
1502
0
    }
1503
1504
0
    void replaceInInitializer(llvm::Constant *init) {
1505
      // Remember the type of the top-most initializer.
1506
0
      BaseValueTy = init->getType();
1507
1508
      // Initialize the stack.
1509
0
      Indices.push_back(0);
1510
0
      IndexValues.push_back(nullptr);
1511
1512
      // Recurse into the initializer.
1513
0
      findLocations(init);
1514
1515
      // Check invariants.
1516
0
      assert(IndexValues.size() == Indices.size() && "mismatch");
1517
0
      assert(Indices.size() == 1 && "didn't pop all indices");
1518
1519
      // Do the replacement; this basically invalidates 'init'.
1520
0
      assert(Locations.size() == PlaceholderAddresses.size() &&
1521
0
             "missed a placeholder?");
1522
1523
      // We're iterating over a hashtable, so this would be a source of
1524
      // non-determinism in compiler output *except* that we're just
1525
      // messing around with llvm::Constant structures, which never itself
1526
      // does anything that should be visible in compiler output.
1527
0
      for (auto &entry : Locations) {
1528
0
        assert(entry.first->getParent() == nullptr && "not a placeholder!");
1529
0
        entry.first->replaceAllUsesWith(entry.second);
1530
0
        entry.first->eraseFromParent();
1531
0
      }
1532
0
    }
1533
1534
  private:
1535
0
    void findLocations(llvm::Constant *init) {
1536
      // Recurse into aggregates.
1537
0
      if (auto agg = dyn_cast<llvm::ConstantAggregate>(init)) {
1538
0
        for (unsigned i = 0, e = agg->getNumOperands(); i != e; ++i) {
1539
0
          Indices.push_back(i);
1540
0
          IndexValues.push_back(nullptr);
1541
1542
0
          findLocations(agg->getOperand(i));
1543
1544
0
          IndexValues.pop_back();
1545
0
          Indices.pop_back();
1546
0
        }
1547
0
        return;
1548
0
      }
1549
1550
      // Otherwise, check for registered constants.
1551
0
      while (true) {
1552
0
        auto it = PlaceholderAddresses.find(init);
1553
0
        if (it != PlaceholderAddresses.end()) {
1554
0
          setLocation(it->second);
1555
0
          break;
1556
0
        }
1557
1558
        // Look through bitcasts or other expressions.
1559
0
        if (auto expr = dyn_cast<llvm::ConstantExpr>(init)) {
1560
0
          init = expr->getOperand(0);
1561
0
        } else {
1562
0
          break;
1563
0
        }
1564
0
      }
1565
0
    }
1566
1567
0
    void setLocation(llvm::GlobalVariable *placeholder) {
1568
0
      assert(Locations.find(placeholder) == Locations.end() &&
1569
0
             "already found location for placeholder!");
1570
1571
      // Lazily fill in IndexValues with the values from Indices.
1572
      // We do this in reverse because we should always have a strict
1573
      // prefix of indices from the start.
1574
0
      assert(Indices.size() == IndexValues.size());
1575
0
      for (size_t i = Indices.size() - 1; i != size_t(-1); --i) {
1576
0
        if (IndexValues[i]) {
1577
0
#ifndef NDEBUG
1578
0
          for (size_t j = 0; j != i + 1; ++j) {
1579
0
            assert(IndexValues[j] &&
1580
0
                   isa<llvm::ConstantInt>(IndexValues[j]) &&
1581
0
                   cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue()
1582
0
                     == Indices[j]);
1583
0
          }
1584
0
#endif
1585
0
          break;
1586
0
        }
1587
1588
0
        IndexValues[i] = llvm::ConstantInt::get(CGM.Int32Ty, Indices[i]);
1589
0
      }
1590
1591
      // Form a GEP and then bitcast to the placeholder type so that the
1592
      // replacement will succeed.
1593
0
      llvm::Constant *location =
1594
0
        llvm::ConstantExpr::getInBoundsGetElementPtr(BaseValueTy,
1595
0
                                                     Base, IndexValues);
1596
0
      location = llvm::ConstantExpr::getBitCast(location,
1597
0
                                                placeholder->getType());
1598
1599
0
      Locations.insert({placeholder, location});
1600
0
    }
1601
  };
1602
}
1603
1604
18.0k
void ConstantEmitter::finalize(llvm::GlobalVariable *global) {
1605
18.0k
  assert(InitializedNonAbstract &&
1606
18.0k
         "finalizing emitter that was used for abstract emission?");
1607
0
  assert(!Finalized && "finalizing emitter multiple times");
1608
0
  assert(global->getInitializer());
1609
1610
  // Note that we might also be Failed.
1611
0
  Finalized = true;
1612
1613
18.0k
  if (!PlaceholderAddresses.empty()) {
1614
0
    ReplacePlaceholders(CGM, global, PlaceholderAddresses)
1615
0
      .replaceInInitializer(global->getInitializer());
1616
0
    PlaceholderAddresses.clear(); // satisfy
1617
0
  }
1618
18.0k
}
1619
1620
54.8k
ConstantEmitter::~ConstantEmitter() {
1621
54.8k
  assert((!InitializedNonAbstract || Finalized || Failed) &&
1622
54.8k
         "not finalized after being initialized for non-abstract emission");
1623
0
  assert(PlaceholderAddresses.empty() && "unhandled placeholders");
1624
54.8k
}
1625
1626
69.2k
static QualType getNonMemoryType(CodeGenModule &CGM, QualType type) {
1627
69.2k
  if (auto AT = type->getAs<AtomicType>()) {
1628
101
    return CGM.getContext().getQualifiedType(AT->getValueType(),
1629
101
                                             type.getQualifiers());
1630
101
  }
1631
69.1k
  return type;
1632
69.2k
}
1633
1634
46.5k
llvm::Constant *ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &D) {
1635
  // Make a quick check if variable can be default NULL initialized
1636
  // and avoid going through rest of code which may do, for c++11,
1637
  // initialization of memory to all NULLs.
1638
46.5k
  if (!D.hasLocalStorage()) {
1639
26.6k
    QualType Ty = CGM.getContext().getBaseElementType(D.getType());
1640
26.6k
    if (Ty->isRecordType())
1641
7.41k
      if (const CXXConstructExpr *E =
1642
7.41k
          dyn_cast_or_null<CXXConstructExpr>(D.getInit())) {
1643
6.30k
        const CXXConstructorDecl *CD = E->getConstructor();
1644
6.30k
        if (CD->isTrivial() && 
CD->isDefaultConstructor()1.32k
)
1645
1.29k
          return CGM.EmitNullConstant(D.getType());
1646
6.30k
      }
1647
26.6k
  }
1648
45.3k
  InConstantContext = D.hasConstantInitialization();
1649
1650
45.3k
  QualType destType = D.getType();
1651
1652
  // Try to emit the initializer.  Note that this can allow some things that
1653
  // are not allowed by tryEmitPrivateForMemory alone.
1654
45.3k
  if (auto value = D.evaluateValue()) {
1655
13.8k
    return tryEmitPrivateForMemory(*value, destType);
1656
13.8k
  }
1657
1658
  // FIXME: Implement C++11 [basic.start.init]p2: if the initializer of a
1659
  // reference is a constant expression, and the reference binds to a temporary,
1660
  // then constant initialization is performed. ConstExprEmitter will
1661
  // incorrectly emit a prvalue constant in this case, and the calling code
1662
  // interprets that as the (pointer) value of the reference, rather than the
1663
  // desired value of the referee.
1664
31.4k
  if (destType->isReferenceType())
1665
3.46k
    return nullptr;
1666
1667
27.9k
  const Expr *E = D.getInit();
1668
27.9k
  assert(E && "No initializer to emit");
1669
1670
0
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1671
27.9k
  auto C =
1672
27.9k
    ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), nonMemoryDestType);
1673
27.9k
  return (C ? 
emitForMemory(C, destType)2.19k
:
nullptr25.7k
);
1674
31.4k
}
1675
1676
llvm::Constant *
1677
156
ConstantEmitter::tryEmitAbstractForMemory(const Expr *E, QualType destType) {
1678
156
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1679
156
  auto C = tryEmitAbstract(E, nonMemoryDestType);
1680
156
  return (C ? 
emitForMemory(C, destType)145
:
nullptr11
);
1681
156
}
1682
1683
llvm::Constant *
1684
ConstantEmitter::tryEmitAbstractForMemory(const APValue &value,
1685
690
                                          QualType destType) {
1686
690
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1687
690
  auto C = tryEmitAbstract(value, nonMemoryDestType);
1688
690
  return (C ? emitForMemory(C, destType) : 
nullptr0
);
1689
690
}
1690
1691
llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const Expr *E,
1692
10.9k
                                                         QualType destType) {
1693
10.9k
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1694
10.9k
  llvm::Constant *C = tryEmitPrivate(E, nonMemoryDestType);
1695
10.9k
  return (C ? 
emitForMemory(C, destType)10.4k
:
nullptr473
);
1696
10.9k
}
1697
1698
llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const APValue &value,
1699
29.6k
                                                         QualType destType) {
1700
29.6k
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1701
29.6k
  auto C = tryEmitPrivate(value, nonMemoryDestType);
1702
29.6k
  return (C ? emitForMemory(C, destType) : 
nullptr0
);
1703
29.6k
}
1704
1705
llvm::Constant *ConstantEmitter::emitForMemory(CodeGenModule &CGM,
1706
                                               llvm::Constant *C,
1707
43.2k
                                               QualType destType) {
1708
  // For an _Atomic-qualified constant, we may need to add tail padding.
1709
43.2k
  if (auto AT = destType->getAs<AtomicType>()) {
1710
97
    QualType destValueType = AT->getValueType();
1711
97
    C = emitForMemory(CGM, C, destValueType);
1712
1713
97
    uint64_t innerSize = CGM.getContext().getTypeSize(destValueType);
1714
97
    uint64_t outerSize = CGM.getContext().getTypeSize(destType);
1715
97
    if (innerSize == outerSize)
1716
96
      return C;
1717
1718
1
    assert(innerSize < outerSize && "emitted over-large constant for atomic");
1719
0
    llvm::Constant *elts[] = {
1720
1
      C,
1721
1
      llvm::ConstantAggregateZero::get(
1722
1
          llvm::ArrayType::get(CGM.Int8Ty, (outerSize - innerSize) / 8))
1723
1
    };
1724
1
    return llvm::ConstantStruct::getAnon(elts);
1725
97
  }
1726
1727
  // Zero-extend bool.
1728
43.1k
  if (C->getType()->isIntegerTy(1)) {
1729
389
    llvm::Type *boolTy = CGM.getTypes().ConvertTypeForMem(destType);
1730
389
    return llvm::ConstantExpr::getZExt(C, boolTy);
1731
389
  }
1732
1733
42.7k
  return C;
1734
43.1k
}
1735
1736
llvm::Constant *ConstantEmitter::tryEmitPrivate(const Expr *E,
1737
11.8k
                                                QualType destType) {
1738
11.8k
  assert(!destType->isVoidType() && "can't emit a void constant");
1739
1740
0
  Expr::EvalResult Result;
1741
1742
11.8k
  bool Success = false;
1743
1744
11.8k
  if (destType->isReferenceType())
1745
11
    Success = E->EvaluateAsLValue(Result, CGM.getContext());
1746
11.8k
  else
1747
11.8k
    Success = E->EvaluateAsRValue(Result, CGM.getContext(), InConstantContext);
1748
1749
11.8k
  llvm::Constant *C;
1750
11.8k
  if (Success && 
!Result.HasSideEffects10.1k
)
1751
10.1k
    C = tryEmitPrivate(Result.Val, destType);
1752
1.70k
  else
1753
1.70k
    C = ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), destType);
1754
1755
11.8k
  return C;
1756
11.8k
}
1757
1758
35.4k
llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) {
1759
35.4k
  return getTargetCodeGenInfo().getNullPointer(*this, T, QT);
1760
35.4k
}
1761
1762
namespace {
1763
/// A struct which can be used to peephole certain kinds of finalization
1764
/// that normally happen during l-value emission.
1765
struct ConstantLValue {
1766
  llvm::Constant *Value;
1767
  bool HasOffsetApplied;
1768
1769
  /*implicit*/ ConstantLValue(llvm::Constant *value,
1770
                              bool hasOffsetApplied = false)
1771
5.56k
    : Value(value), HasOffsetApplied(hasOffsetApplied) {}
1772
1773
  /*implicit*/ ConstantLValue(ConstantAddress address)
1774
2.09k
    : ConstantLValue(address.getPointer()) {}
1775
};
1776
1777
/// A helper class for emitting constant l-values.
1778
class ConstantLValueEmitter : public ConstStmtVisitor<ConstantLValueEmitter,
1779
                                                      ConstantLValue> {
1780
  CodeGenModule &CGM;
1781
  ConstantEmitter &Emitter;
1782
  const APValue &Value;
1783
  QualType DestType;
1784
1785
  // Befriend StmtVisitorBase so that we don't have to expose Visit*.
1786
  friend StmtVisitorBase;
1787
1788
public:
1789
  ConstantLValueEmitter(ConstantEmitter &emitter, const APValue &value,
1790
                        QualType destType)
1791
6.25k
    : CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType) {}
1792
1793
  llvm::Constant *tryEmit();
1794
1795
private:
1796
  llvm::Constant *tryEmitAbsolute(llvm::Type *destTy);
1797
  ConstantLValue tryEmitBase(const APValue::LValueBase &base);
1798
1799
0
  ConstantLValue VisitStmt(const Stmt *S) { return nullptr; }
1800
  ConstantLValue VisitConstantExpr(const ConstantExpr *E);
1801
  ConstantLValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
1802
  ConstantLValue VisitStringLiteral(const StringLiteral *E);
1803
  ConstantLValue VisitObjCBoxedExpr(const ObjCBoxedExpr *E);
1804
  ConstantLValue VisitObjCEncodeExpr(const ObjCEncodeExpr *E);
1805
  ConstantLValue VisitObjCStringLiteral(const ObjCStringLiteral *E);
1806
  ConstantLValue VisitPredefinedExpr(const PredefinedExpr *E);
1807
  ConstantLValue VisitAddrLabelExpr(const AddrLabelExpr *E);
1808
  ConstantLValue VisitCallExpr(const CallExpr *E);
1809
  ConstantLValue VisitBlockExpr(const BlockExpr *E);
1810
  ConstantLValue VisitCXXTypeidExpr(const CXXTypeidExpr *E);
1811
  ConstantLValue VisitMaterializeTemporaryExpr(
1812
                                         const MaterializeTemporaryExpr *E);
1813
1814
5.56k
  bool hasNonZeroOffset() const {
1815
5.56k
    return !Value.getLValueOffset().isZero();
1816
5.56k
  }
1817
1818
  /// Return the value offset.
1819
252
  llvm::Constant *getOffset() {
1820
252
    return llvm::ConstantInt::get(CGM.Int64Ty,
1821
252
                                  Value.getLValueOffset().getQuantity());
1822
252
  }
1823
1824
  /// Apply the value offset to the given constant.
1825
5.56k
  llvm::Constant *applyOffset(llvm::Constant *C) {
1826
5.56k
    if (!hasNonZeroOffset())
1827
5.50k
      return C;
1828
1829
56
    llvm::Type *origPtrTy = C->getType();
1830
56
    unsigned AS = origPtrTy->getPointerAddressSpace();
1831
56
    llvm::Type *charPtrTy = CGM.Int8Ty->getPointerTo(AS);
1832
56
    C = llvm::ConstantExpr::getBitCast(C, charPtrTy);
1833
56
    C = llvm::ConstantExpr::getGetElementPtr(CGM.Int8Ty, C, getOffset());
1834
56
    C = llvm::ConstantExpr::getPointerCast(C, origPtrTy);
1835
56
    return C;
1836
5.56k
  }
1837
};
1838
1839
}
1840
1841
6.25k
llvm::Constant *ConstantLValueEmitter::tryEmit() {
1842
6.25k
  const APValue::LValueBase &base = Value.getLValueBase();
1843
1844
  // The destination type should be a pointer or reference
1845
  // type, but it might also be a cast thereof.
1846
  //
1847
  // FIXME: the chain of casts required should be reflected in the APValue.
1848
  // We need this in order to correctly handle things like a ptrtoint of a
1849
  // non-zero null pointer and addrspace casts that aren't trivially
1850
  // represented in LLVM IR.
1851
6.25k
  auto destTy = CGM.getTypes().ConvertTypeForMem(DestType);
1852
6.25k
  assert(isa<llvm::IntegerType>(destTy) || isa<llvm::PointerType>(destTy));
1853
1854
  // If there's no base at all, this is a null or absolute pointer,
1855
  // possibly cast back to an integer type.
1856
6.25k
  if (!base) {
1857
689
    return tryEmitAbsolute(destTy);
1858
689
  }
1859
1860
  // Otherwise, try to emit the base.
1861
5.56k
  ConstantLValue result = tryEmitBase(base);
1862
1863
  // If that failed, we're done.
1864
5.56k
  llvm::Constant *value = result.Value;
1865
5.56k
  if (!value) 
return nullptr0
;
1866
1867
  // Apply the offset if necessary and not already done.
1868
5.56k
  if (!result.HasOffsetApplied) {
1869
5.56k
    value = applyOffset(value);
1870
5.56k
  }
1871
1872
  // Convert to the appropriate type; this could be an lvalue for
1873
  // an integer.  FIXME: performAddrSpaceCast
1874
5.56k
  if (isa<llvm::PointerType>(destTy))
1875
5.54k
    return llvm::ConstantExpr::getPointerCast(value, destTy);
1876
1877
19
  return llvm::ConstantExpr::getPtrToInt(value, destTy);
1878
5.56k
}
1879
1880
/// Try to emit an absolute l-value, such as a null pointer or an integer
1881
/// bitcast to pointer type.
1882
llvm::Constant *
1883
689
ConstantLValueEmitter::tryEmitAbsolute(llvm::Type *destTy) {
1884
  // If we're producing a pointer, this is easy.
1885
689
  auto destPtrTy = cast<llvm::PointerType>(destTy);
1886
689
  if (Value.isNullPointer()) {
1887
    // FIXME: integer offsets from non-zero null pointers.
1888
493
    return CGM.getNullPointer(destPtrTy, DestType);
1889
493
  }
1890
1891
  // Convert the integer to a pointer-sized integer before converting it
1892
  // to a pointer.
1893
  // FIXME: signedness depends on the original integer type.
1894
196
  auto intptrTy = CGM.getDataLayout().getIntPtrType(destPtrTy);
1895
196
  llvm::Constant *C;
1896
196
  C = llvm::ConstantExpr::getIntegerCast(getOffset(), intptrTy,
1897
196
                                         /*isSigned*/ false);
1898
196
  C = llvm::ConstantExpr::getIntToPtr(C, destPtrTy);
1899
196
  return C;
1900
689
}
1901
1902
ConstantLValue
1903
5.56k
ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) {
1904
  // Handle values.
1905
5.56k
  if (const ValueDecl *D = base.dyn_cast<const ValueDecl*>()) {
1906
    // The constant always points to the canonical declaration. We want to look
1907
    // at properties of the most recent declaration at the point of emission.
1908
3.24k
    D = cast<ValueDecl>(D->getMostRecentDecl());
1909
1910
3.24k
    if (D->hasAttr<WeakRefAttr>())
1911
5
      return CGM.GetWeakRefReference(D).getPointer();
1912
1913
3.24k
    if (auto FD = dyn_cast<FunctionDecl>(D))
1914
2.33k
      return CGM.GetAddrOfFunction(FD);
1915
1916
911
    if (auto VD = dyn_cast<VarDecl>(D)) {
1917
      // We can never refer to a variable with local storage.
1918
833
      if (!VD->hasLocalStorage()) {
1919
833
        if (VD->isFileVarDecl() || 
VD->hasExternalStorage()16
)
1920
818
          return CGM.GetAddrOfGlobalVar(VD);
1921
1922
15
        if (VD->isLocalVarDecl()) {
1923
15
          return CGM.getOrCreateStaticVarDecl(
1924
15
              *VD, CGM.getLLVMLinkageVarDefinition(VD, /*IsConstant=*/false));
1925
15
        }
1926
15
      }
1927
833
    }
1928
1929
78
    if (auto *GD = dyn_cast<MSGuidDecl>(D))
1930
36
      return CGM.GetAddrOfMSGuidDecl(GD);
1931
1932
42
    if (auto *GCD = dyn_cast<UnnamedGlobalConstantDecl>(D))
1933
38
      return CGM.GetAddrOfUnnamedGlobalConstantDecl(GCD);
1934
1935
4
    if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(D))
1936
4
      return CGM.GetAddrOfTemplateParamObject(TPO);
1937
1938
0
    return nullptr;
1939
4
  }
1940
1941
  // Handle typeid(T).
1942
2.31k
  if (TypeInfoLValue TI = base.dyn_cast<TypeInfoLValue>()) {
1943
142
    llvm::Type *StdTypeInfoPtrTy =
1944
142
        CGM.getTypes().ConvertType(base.getTypeInfoType())->getPointerTo();
1945
142
    llvm::Constant *TypeInfo =
1946
142
        CGM.GetAddrOfRTTIDescriptor(QualType(TI.getType(), 0));
1947
142
    if (TypeInfo->getType() != StdTypeInfoPtrTy)
1948
45
      TypeInfo = llvm::ConstantExpr::getBitCast(TypeInfo, StdTypeInfoPtrTy);
1949
142
    return TypeInfo;
1950
142
  }
1951
1952
  // Otherwise, it must be an expression.
1953
2.17k
  return Visit(base.get<const Expr*>());
1954
2.31k
}
1955
1956
ConstantLValue
1957
0
ConstantLValueEmitter::VisitConstantExpr(const ConstantExpr *E) {
1958
0
  if (llvm::Constant *Result = Emitter.tryEmitConstantExpr(E))
1959
0
    return Result;
1960
0
  return Visit(E->getSubExpr());
1961
0
}
1962
1963
ConstantLValue
1964
20
ConstantLValueEmitter::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
1965
20
  return tryEmitGlobalCompoundLiteral(CGM, Emitter.CGF, E);
1966
20
}
1967
1968
ConstantLValue
1969
1.15k
ConstantLValueEmitter::VisitStringLiteral(const StringLiteral *E) {
1970
1.15k
  return CGM.GetAddrOfConstantStringFromLiteral(E);
1971
1.15k
}
1972
1973
ConstantLValue
1974
54
ConstantLValueEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
1975
54
  return CGM.GetAddrOfConstantStringFromObjCEncode(E);
1976
54
}
1977
1978
static ConstantLValue emitConstantObjCStringLiteral(const StringLiteral *S,
1979
                                                    QualType T,
1980
292
                                                    CodeGenModule &CGM) {
1981
292
  auto C = CGM.getObjCRuntime().GenerateConstantString(S);
1982
292
  return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(T));
1983
292
}
1984
1985
ConstantLValue
1986
289
ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) {
1987
289
  return emitConstantObjCStringLiteral(E->getString(), E->getType(), CGM);
1988
289
}
1989
1990
ConstantLValue
1991
3
ConstantLValueEmitter::VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
1992
3
  assert(E->isExpressibleAsConstantInitializer() &&
1993
3
         "this boxed expression can't be emitted as a compile-time constant");
1994
0
  auto *SL = cast<StringLiteral>(E->getSubExpr()->IgnoreParenCasts());
1995
3
  return emitConstantObjCStringLiteral(SL, E->getType(), CGM);
1996
3
}
1997
1998
ConstantLValue
1999
3
ConstantLValueEmitter::VisitPredefinedExpr(const PredefinedExpr *E) {
2000
3
  return CGM.GetAddrOfConstantStringFromLiteral(E->getFunctionName());
2001
3
}
2002
2003
ConstantLValue
2004
36
ConstantLValueEmitter::VisitAddrLabelExpr(const AddrLabelExpr *E) {
2005
36
  assert(Emitter.CGF && "Invalid address of label expression outside function");
2006
0
  llvm::Constant *Ptr = Emitter.CGF->GetAddrOfLabel(E->getLabel());
2007
36
  Ptr = llvm::ConstantExpr::getBitCast(Ptr,
2008
36
                                   CGM.getTypes().ConvertType(E->getType()));
2009
36
  return Ptr;
2010
36
}
2011
2012
ConstantLValue
2013
344
ConstantLValueEmitter::VisitCallExpr(const CallExpr *E) {
2014
344
  unsigned builtin = E->getBuiltinCallee();
2015
344
  if (builtin == Builtin::BI__builtin_function_start)
2016
3
    return CGM.GetFunctionStart(
2017
3
        E->getArg(0)->getAsBuiltinConstantDeclRef(CGM.getContext()));
2018
341
  if (builtin != Builtin::BI__builtin___CFStringMakeConstantString &&
2019
341
      
builtin != Builtin::BI__builtin___NSStringMakeConstantString0
)
2020
0
    return nullptr;
2021
2022
341
  auto literal = cast<StringLiteral>(E->getArg(0)->IgnoreParenCasts());
2023
341
  if (builtin == Builtin::BI__builtin___NSStringMakeConstantString) {
2024
0
    return CGM.getObjCRuntime().GenerateConstantString(literal);
2025
341
  } else {
2026
    // FIXME: need to deal with UCN conversion issues.
2027
341
    return CGM.GetAddrOfConstantCFString(literal);
2028
341
  }
2029
341
}
2030
2031
ConstantLValue
2032
120
ConstantLValueEmitter::VisitBlockExpr(const BlockExpr *E) {
2033
120
  StringRef functionName;
2034
120
  if (auto CGF = Emitter.CGF)
2035
71
    functionName = CGF->CurFn->getName();
2036
49
  else
2037
49
    functionName = "global";
2038
2039
120
  return CGM.GetAddrOfGlobalBlock(E, functionName);
2040
120
}
2041
2042
ConstantLValue
2043
0
ConstantLValueEmitter::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
2044
0
  QualType T;
2045
0
  if (E->isTypeOperand())
2046
0
    T = E->getTypeOperand(CGM.getContext());
2047
0
  else
2048
0
    T = E->getExprOperand()->getType();
2049
0
  return CGM.GetAddrOfRTTIDescriptor(T);
2050
0
}
2051
2052
ConstantLValue
2053
ConstantLValueEmitter::VisitMaterializeTemporaryExpr(
2054
148
                                            const MaterializeTemporaryExpr *E) {
2055
148
  assert(E->getStorageDuration() == SD_Static);
2056
0
  SmallVector<const Expr *, 2> CommaLHSs;
2057
148
  SmallVector<SubobjectAdjustment, 2> Adjustments;
2058
148
  const Expr *Inner =
2059
148
      E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
2060
148
  return CGM.GetAddrOfGlobalTemporary(E, Inner);
2061
148
}
2062
2063
llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
2064
47.6k
                                                QualType DestType) {
2065
47.6k
  switch (Value.getKind()) {
2066
0
  case APValue::None:
2067
0
  case APValue::Indeterminate:
2068
    // Out-of-lifetime and indeterminate values can be modeled as 'undef'.
2069
0
    return llvm::UndefValue::get(CGM.getTypes().ConvertType(DestType));
2070
6.25k
  case APValue::LValue:
2071
6.25k
    return ConstantLValueEmitter(*this, Value, DestType).tryEmit();
2072
30.5k
  case APValue::Int:
2073
30.5k
    return llvm::ConstantInt::get(CGM.getLLVMContext(), Value.getInt());
2074
344
  case APValue::FixedPoint:
2075
344
    return llvm::ConstantInt::get(CGM.getLLVMContext(),
2076
344
                                  Value.getFixedPoint().getValue());
2077
7
  case APValue::ComplexInt: {
2078
7
    llvm::Constant *Complex[2];
2079
2080
7
    Complex[0] = llvm::ConstantInt::get(CGM.getLLVMContext(),
2081
7
                                        Value.getComplexIntReal());
2082
7
    Complex[1] = llvm::ConstantInt::get(CGM.getLLVMContext(),
2083
7
                                        Value.getComplexIntImag());
2084
2085
    // FIXME: the target may want to specify that this is packed.
2086
7
    llvm::StructType *STy =
2087
7
        llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
2088
7
    return llvm::ConstantStruct::get(STy, Complex);
2089
0
  }
2090
2.76k
  case APValue::Float: {
2091
2.76k
    const llvm::APFloat &Init = Value.getFloat();
2092
2.76k
    if (&Init.getSemantics() == &llvm::APFloat::IEEEhalf() &&
2093
2.76k
        
!CGM.getContext().getLangOpts().NativeHalfType67
&&
2094
2.76k
        
CGM.getContext().getTargetInfo().useFP16ConversionIntrinsics()55
)
2095
1
      return llvm::ConstantInt::get(CGM.getLLVMContext(),
2096
1
                                    Init.bitcastToAPInt());
2097
2.76k
    else
2098
2.76k
      return llvm::ConstantFP::get(CGM.getLLVMContext(), Init);
2099
2.76k
  }
2100
40
  case APValue::ComplexFloat: {
2101
40
    llvm::Constant *Complex[2];
2102
2103
40
    Complex[0] = llvm::ConstantFP::get(CGM.getLLVMContext(),
2104
40
                                       Value.getComplexFloatReal());
2105
40
    Complex[1] = llvm::ConstantFP::get(CGM.getLLVMContext(),
2106
40
                                       Value.getComplexFloatImag());
2107
2108
    // FIXME: the target may want to specify that this is packed.
2109
40
    llvm::StructType *STy =
2110
40
        llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
2111
40
    return llvm::ConstantStruct::get(STy, Complex);
2112
2.76k
  }
2113
919
  case APValue::Vector: {
2114
919
    unsigned NumElts = Value.getVectorLength();
2115
919
    SmallVector<llvm::Constant *, 4> Inits(NumElts);
2116
2117
6.48k
    for (unsigned I = 0; I != NumElts; 
++I5.57k
) {
2118
5.57k
      const APValue &Elt = Value.getVectorElt(I);
2119
5.57k
      if (Elt.isInt())
2120
4.58k
        Inits[I] = llvm::ConstantInt::get(CGM.getLLVMContext(), Elt.getInt());
2121
983
      else if (Elt.isFloat())
2122
983
        Inits[I] = llvm::ConstantFP::get(CGM.getLLVMContext(), Elt.getFloat());
2123
0
      else
2124
0
        llvm_unreachable("unsupported vector element type");
2125
5.57k
    }
2126
919
    return llvm::ConstantVector::get(Inits);
2127
2.76k
  }
2128
5
  case APValue::AddrLabelDiff: {
2129
5
    const AddrLabelExpr *LHSExpr = Value.getAddrLabelDiffLHS();
2130
5
    const AddrLabelExpr *RHSExpr = Value.getAddrLabelDiffRHS();
2131
5
    llvm::Constant *LHS = tryEmitPrivate(LHSExpr, LHSExpr->getType());
2132
5
    llvm::Constant *RHS = tryEmitPrivate(RHSExpr, RHSExpr->getType());
2133
5
    if (!LHS || !RHS) 
return nullptr0
;
2134
2135
    // Compute difference
2136
5
    llvm::Type *ResultType = CGM.getTypes().ConvertType(DestType);
2137
5
    LHS = llvm::ConstantExpr::getPtrToInt(LHS, CGM.IntPtrTy);
2138
5
    RHS = llvm::ConstantExpr::getPtrToInt(RHS, CGM.IntPtrTy);
2139
5
    llvm::Constant *AddrLabelDiff = llvm::ConstantExpr::getSub(LHS, RHS);
2140
2141
    // LLVM is a bit sensitive about the exact format of the
2142
    // address-of-label difference; make sure to truncate after
2143
    // the subtraction.
2144
5
    return llvm::ConstantExpr::getTruncOrBitCast(AddrLabelDiff, ResultType);
2145
5
  }
2146
2.95k
  case APValue::Struct:
2147
3.43k
  case APValue::Union:
2148
3.43k
    return ConstStructBuilder::BuildStruct(*this, Value, DestType);
2149
3.08k
  case APValue::Array: {
2150
3.08k
    const ArrayType *ArrayTy = CGM.getContext().getAsArrayType(DestType);
2151
3.08k
    unsigned NumElements = Value.getArraySize();
2152
3.08k
    unsigned NumInitElts = Value.getArrayInitializedElts();
2153
2154
    // Emit array filler, if there is one.
2155
3.08k
    llvm::Constant *Filler = nullptr;
2156
3.08k
    if (Value.hasArrayFiller()) {
2157
690
      Filler = tryEmitAbstractForMemory(Value.getArrayFiller(),
2158
690
                                        ArrayTy->getElementType());
2159
690
      if (!Filler)
2160
0
        return nullptr;
2161
690
    }
2162
2163
    // Emit initializer elements.
2164
3.08k
    SmallVector<llvm::Constant*, 16> Elts;
2165
3.08k
    if (Filler && 
Filler->isNullValue()690
)
2166
682
      Elts.reserve(NumInitElts + 1);
2167
2.40k
    else
2168
2.40k
      Elts.reserve(NumElements);
2169
2170
3.08k
    llvm::Type *CommonElementType = nullptr;
2171
12.9k
    for (unsigned I = 0; I < NumInitElts; 
++I9.84k
) {
2172
9.84k
      llvm::Constant *C = tryEmitPrivateForMemory(
2173
9.84k
          Value.getArrayInitializedElt(I), ArrayTy->getElementType());
2174
9.84k
      if (!C) 
return nullptr0
;
2175
2176
9.84k
      if (I == 0)
2177
2.86k
        CommonElementType = C->getType();
2178
6.97k
      else if (C->getType() != CommonElementType)
2179
11
        CommonElementType = nullptr;
2180
9.84k
      Elts.push_back(C);
2181
9.84k
    }
2182
2183
3.08k
    llvm::ArrayType *Desired =
2184
3.08k
        cast<llvm::ArrayType>(CGM.getTypes().ConvertType(DestType));
2185
3.08k
    return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
2186
3.08k
                             Filler);
2187
3.08k
  }
2188
251
  case APValue::MemberPointer:
2189
251
    return CGM.getCXXABI().EmitMemberPointer(Value, DestType);
2190
47.6k
  }
2191
0
  llvm_unreachable("Unknown APValue kind");
2192
0
}
2193
2194
llvm::GlobalVariable *CodeGenModule::getAddrOfConstantCompoundLiteralIfEmitted(
2195
23
    const CompoundLiteralExpr *E) {
2196
23
  return EmittedCompoundLiterals.lookup(E);
2197
23
}
2198
2199
void CodeGenModule::setAddrOfConstantCompoundLiteral(
2200
21
    const CompoundLiteralExpr *CLE, llvm::GlobalVariable *GV) {
2201
21
  bool Ok = EmittedCompoundLiterals.insert(std::make_pair(CLE, GV)).second;
2202
21
  (void)Ok;
2203
21
  assert(Ok && "CLE has already been emitted!");
2204
21
}
2205
2206
ConstantAddress
2207
3
CodeGenModule::GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr *E) {
2208
3
  assert(E->isFileScope() && "not a file-scope compound literal expr");
2209
0
  return tryEmitGlobalCompoundLiteral(*this, nullptr, E);
2210
3
}
2211
2212
llvm::Constant *
2213
607
CodeGenModule::getMemberPointerConstant(const UnaryOperator *uo) {
2214
  // Member pointer constants always have a very particular form.
2215
607
  const MemberPointerType *type = cast<MemberPointerType>(uo->getType());
2216
607
  const ValueDecl *decl = cast<DeclRefExpr>(uo->getSubExpr())->getDecl();
2217
2218
  // A member function pointer.
2219
607
  if (const CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(decl))
2220
552
    return getCXXABI().EmitMemberFunctionPointer(method);
2221
2222
  // Otherwise, a member data pointer.
2223
55
  uint64_t fieldOffset = getContext().getFieldOffset(decl);
2224
55
  CharUnits chars = getContext().toCharUnitsFromBits((int64_t) fieldOffset);
2225
55
  return getCXXABI().EmitMemberDataPointer(type, chars);
2226
607
}
2227
2228
static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
2229
                                               llvm::Type *baseType,
2230
                                               const CXXRecordDecl *base);
2231
2232
static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
2233
                                        const RecordDecl *record,
2234
73
                                        bool asCompleteObject) {
2235
73
  const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record);
2236
73
  llvm::StructType *structure =
2237
73
    (asCompleteObject ? 
layout.getLLVMType()45
2238
73
                      : 
layout.getBaseSubobjectLLVMType()28
);
2239
2240
73
  unsigned numElements = structure->getNumElements();
2241
73
  std::vector<llvm::Constant *> elements(numElements);
2242
2243
73
  auto CXXR = dyn_cast<CXXRecordDecl>(record);
2244
  // Fill in all the bases.
2245
73
  if (CXXR) {
2246
57
    for (const auto &I : CXXR->bases()) {
2247
26
      if (I.isVirtual()) {
2248
        // Ignore virtual bases; if we're laying out for a complete
2249
        // object, we'll lay these out later.
2250
17
        continue;
2251
17
      }
2252
2253
9
      const CXXRecordDecl *base =
2254
9
        cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
2255
2256
      // Ignore empty bases.
2257
9
      if (base->isEmpty() ||
2258
9
          CGM.getContext().getASTRecordLayout(base).getNonVirtualSize()
2259
9
              .isZero())
2260
1
        continue;
2261
2262
8
      unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
2263
8
      llvm::Type *baseType = structure->getElementType(fieldIndex);
2264
8
      elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
2265
8
    }
2266
57
  }
2267
2268
  // Fill in all the fields.
2269
144
  for (const auto *Field : record->fields()) {
2270
    // Fill in non-bitfields. (Bitfields always use a zero pattern, which we
2271
    // will fill in later.)
2272
144
    if (!Field->isBitField() && 
!Field->isZeroSize(CGM.getContext())142
) {
2273
142
      unsigned fieldIndex = layout.getLLVMFieldNo(Field);
2274
142
      elements[fieldIndex] = CGM.EmitNullConstant(Field->getType());
2275
142
    }
2276
2277
    // For unions, stop after the first named field.
2278
144
    if (record->isUnion()) {
2279
4
      if (Field->getIdentifier())
2280
3
        break;
2281
1
      if (const auto *FieldRD = Field->getType()->getAsRecordDecl())
2282
1
        if (FieldRD->findFirstNamedDataMember())
2283
1
          break;
2284
1
    }
2285
144
  }
2286
2287
  // Fill in the virtual bases, if we're working with the complete object.
2288
73
  if (CXXR && 
asCompleteObject57
) {
2289
29
    for (const auto &I : CXXR->vbases()) {
2290
5
      const CXXRecordDecl *base =
2291
5
        cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
2292
2293
      // Ignore empty bases.
2294
5
      if (base->isEmpty())
2295
0
        continue;
2296
2297
5
      unsigned fieldIndex = layout.getVirtualBaseIndex(base);
2298
2299
      // We might have already laid this field out.
2300
5
      if (elements[fieldIndex]) 
continue0
;
2301
2302
5
      llvm::Type *baseType = structure->getElementType(fieldIndex);
2303
5
      elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
2304
5
    }
2305
29
  }
2306
2307
  // Now go through all other fields and zero them out.
2308
257
  for (unsigned i = 0; i != numElements; 
++i184
) {
2309
184
    if (!elements[i])
2310
29
      elements[i] = llvm::Constant::getNullValue(structure->getElementType(i));
2311
184
  }
2312
2313
73
  return llvm::ConstantStruct::get(structure, elements);
2314
73
}
2315
2316
/// Emit the null constant for a base subobject.
2317
static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
2318
                                               llvm::Type *baseType,
2319
13
                                               const CXXRecordDecl *base) {
2320
13
  const CGRecordLayout &baseLayout = CGM.getTypes().getCGRecordLayout(base);
2321
2322
  // Just zero out bases that don't have any pointer to data members.
2323
13
  if (baseLayout.isZeroInitializableAsBase())
2324
4
    return llvm::Constant::getNullValue(baseType);
2325
2326
  // Otherwise, we can just use its null constant.
2327
9
  return EmitNullConstant(CGM, base, /*asCompleteObject=*/false);
2328
13
}
2329
2330
llvm::Constant *ConstantEmitter::emitNullForMemory(CodeGenModule &CGM,
2331
57
                                                   QualType T) {
2332
57
  return emitForMemory(CGM, CGM.EmitNullConstant(T), T);
2333
57
}
2334
2335
37.8k
llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
2336
37.8k
  if (T->getAs<PointerType>())
2337
9.53k
    return getNullPointer(
2338
9.53k
        cast<llvm::PointerType>(getTypes().ConvertTypeForMem(T)), T);
2339
2340
28.3k
  if (getTypes().isZeroInitializable(T))
2341
28.1k
    return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
2342
2343
147
  if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) {
2344
11
    llvm::ArrayType *ATy =
2345
11
      cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T));
2346
2347
11
    QualType ElementTy = CAT->getElementType();
2348
2349
11
    llvm::Constant *Element =
2350
11
      ConstantEmitter::emitNullForMemory(*this, ElementTy);
2351
11
    unsigned NumElements = CAT->getSize().getZExtValue();
2352
11
    SmallVector<llvm::Constant *, 8> Array(NumElements, Element);
2353
11
    return llvm::ConstantArray::get(ATy, Array);
2354
11
  }
2355
2356
136
  if (const RecordType *RT = T->getAs<RecordType>())
2357
45
    return ::EmitNullConstant(*this, RT->getDecl(), /*complete object*/ true);
2358
2359
91
  assert(T->isMemberDataPointerType() &&
2360
91
         "Should only see pointers to data members here!");
2361
2362
0
  return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>());
2363
136
}
2364
2365
llvm::Constant *
2366
19
CodeGenModule::EmitNullConstantForBase(const CXXRecordDecl *Record) {
2367
19
  return ::EmitNullConstant(*this, Record, false);
2368
19
}