Coverage Report

Created: 2020-09-19 12:23

/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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11.4k
  ConstantAggregateBuilderUtils(CodeGenModule &CGM) : CGM(CGM) {}
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22.8k
  CharUnits getAlignment(const llvm::Constant *C) const {
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22.8k
    return CharUnits::fromQuantity(
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22.8k
        CGM.getDataLayout().getABITypeAlignment(C->getType()));
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22.8k
  }
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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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425
  llvm::Constant *getPadding(CharUnits PadSize) const {
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425
    llvm::Type *Ty = CGM.Int8Ty;
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425
    if (PadSize > CharUnits::One())
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388
      Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity());
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425
    return llvm::UndefValue::get(Ty);
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425
  }
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8
  llvm::Constant *getZeroes(CharUnits ZeroSize) const {
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8
    llvm::Type *Ty = llvm::ArrayType::get(CGM.Int8Ty, 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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5.72k
      : 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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5.68k
  llvm::Constant *build(llvm::Type *DesiredTy, bool AllowOversized) const {
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5.68k
    return buildFrom(CGM, Elems, Offsets, CharUnits::Zero(), Size,
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                     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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  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::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_0, llvm::Constant*> > >(llvm::SmallVector<llvm::Constant*, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_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");
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34
  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
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34
}
CGExprConstant.cpp:void (anonymous namespace)::replace<llvm::SmallVector<clang::CharUnits, 32u>, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_1, clang::CharUnits> > >(llvm::SmallVector<clang::CharUnits, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_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
2
  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::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_2, clang::CharUnits> > >(llvm::SmallVector<clang::CharUnits, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_2, 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
32
  assert(BeginOff <= EndOff && "invalid replacement range");
139
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  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::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_3, llvm::Constant*> > >(llvm::SmallVector<llvm::Constant*, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_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");
139
15
  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::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_4, clang::CharUnits> > >(llvm::SmallVector<clang::CharUnits, 32u>&, unsigned long, unsigned long, llvm::iterator_range<llvm::mapped_iterator<llvm::detail::value_sequence_iterator<unsigned int>, (anonymous namespace)::ConstantAggregateBuilder::split(unsigned long, clang::CharUnits)::$_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
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  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
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  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
140
88
}
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
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static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
138
88
  assert(BeginOff <= EndOff && "invalid replacement range");
139
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  llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
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88
}
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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11.2k
    CharUnits Align = getAlignment(C);
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11.2k
    CharUnits AlignedSize = Size.alignTo(Align);
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11.2k
    if (AlignedSize > Offset || 
Offset.alignTo(Align) != Offset11.1k
)
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104
      NaturalLayout = false;
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11.1k
    else if (AlignedSize < Offset) {
151
54
      Elems.push_back(getPadding(Offset - Size));
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54
      Offsets.push_back(Size);
153
54
    }
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11.2k
    Elems.push_back(C);
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11.2k
    Offsets.push_back(Offset);
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11.2k
    Size = Offset + getSize(C);
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11.2k
    return true;
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11.2k
  }
159
70
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  // Uncommon case: constant overlaps what we've already created.
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70
  llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
162
70
  if (!FirstElemToReplace)
163
0
    return false;
164
70
165
70
  CharUnits CSize = getSize(C);
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  llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + CSize);
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70
  if (!LastElemToReplace)
168
0
    return false;
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70
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70
  assert((FirstElemToReplace == LastElemToReplace || AllowOverwrite) &&
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         "unexpectedly overwriting field");
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70
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70
  replace(Elems, *FirstElemToReplace, *LastElemToReplace, {C});
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70
  replace(Offsets, *FirstElemToReplace, *LastElemToReplace, {Offset});
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  Size = std::max(Size, Offset + CSize);
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70
  NaturalLayout = false;
177
70
  return true;
178
70
}
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bool ConstantAggregateBuilder::addBits(llvm::APInt Bits, uint64_t OffsetInBits,
181
210
                              bool AllowOverwrite) {
182
210
  const ASTContext &Context = CGM.getContext();
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210
  const uint64_t CharWidth = CGM.getContext().getCharWidth();
184
210
185
  // Offset of where we want the first bit to go within the bits of the
186
  // current char.
187
210
  unsigned OffsetWithinChar = OffsetInBits % CharWidth;
188
210
189
  // We split bit-fields up into individual bytes. Walk over the bytes and
190
  // update them.
191
210
  for (CharUnits OffsetInChars =
192
210
           Context.toCharUnitsFromBits(OffsetInBits - OffsetWithinChar);
193
392
       /**/; 
++OffsetInChars182
) {
194
    // Number of bits we want to fill in this char.
195
392
    unsigned WantedBits =
196
392
        std::min((uint64_t)Bits.getBitWidth(), CharWidth - OffsetWithinChar);
197
392
198
    // Get a char containing the bits we want in the right places. The other
199
    // bits have unspecified values.
200
392
    llvm::APInt BitsThisChar = Bits;
201
392
    if (BitsThisChar.getBitWidth() < CharWidth)
202
186
      BitsThisChar = BitsThisChar.zext(CharWidth);
203
392
    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
10
      int Shift = Bits.getBitWidth() - CharWidth + OffsetWithinChar;
207
10
      if (Shift > 0)
208
8
        BitsThisChar.lshrInPlace(Shift);
209
2
      else if (Shift < 0)
210
1
        BitsThisChar = BitsThisChar.shl(-Shift);
211
382
    } else {
212
382
      BitsThisChar = BitsThisChar.shl(OffsetWithinChar);
213
382
    }
214
392
    if (BitsThisChar.getBitWidth() > CharWidth)
215
179
      BitsThisChar = BitsThisChar.trunc(CharWidth);
216
392
217
392
    if (WantedBits == CharWidth) {
218
      // Got a full byte: just add it directly.
219
195
      add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
220
195
          OffsetInChars, AllowOverwrite);
221
197
    } 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
197
      llvm::Optional<size_t> FirstElemToUpdate = splitAt(OffsetInChars);
226
197
      if (!FirstElemToUpdate)
227
0
        return false;
228
197
      llvm::Optional<size_t> LastElemToUpdate =
229
197
          splitAt(OffsetInChars + CharUnits::One());
230
197
      if (!LastElemToUpdate)
231
0
        return false;
232
197
      assert(*LastElemToUpdate - *FirstElemToUpdate < 2 &&
233
197
             "should have at most one element covering one byte");
234
197
235
      // Figure out which bits we want and discard the rest.
236
197
      llvm::APInt UpdateMask(CharWidth, 0);
237
197
      if (CGM.getDataLayout().isBigEndian())
238
1
        UpdateMask.setBits(CharWidth - OffsetWithinChar - WantedBits,
239
1
                           CharWidth - OffsetWithinChar);
240
196
      else
241
196
        UpdateMask.setBits(OffsetWithinChar, OffsetWithinChar + WantedBits);
242
197
      BitsThisChar &= UpdateMask;
243
197
244
197
      if (*FirstElemToUpdate == *LastElemToUpdate ||
245
55
          Elems[*FirstElemToUpdate]->isNullValue() ||
246
163
          
isa<llvm::UndefValue>(Elems[*FirstElemToUpdate])36
) {
247
        // All existing bits are either zero or undef.
248
163
        add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
249
163
            OffsetInChars, /*AllowOverwrite*/ true);
250
34
      } else {
251
34
        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
34
        auto *CI = dyn_cast<llvm::ConstantInt>(ToUpdate);
255
34
        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
34
        assert(CI->getBitWidth() == CharWidth && "splitAt failed");
260
34
        assert((!(CI->getValue() & UpdateMask) || AllowOverwrite) &&
261
34
               "unexpectedly overwriting bitfield");
262
34
        BitsThisChar |= (CI->getValue() & ~UpdateMask);
263
34
        ToUpdate = llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar);
264
34
      }
265
197
    }
266
392
267
    // Stop if we've added all the bits.
268
392
    if (WantedBits == Bits.getBitWidth())
269
210
      break;
270
182
271
    // Remove the consumed bits from Bits.
272
182
    if (!CGM.getDataLayout().isBigEndian())
273
174
      Bits.lshrInPlace(WantedBits);
274
182
    Bits = Bits.trunc(Bits.getBitWidth() - WantedBits);
275
182
276
    // The remanining bits go at the start of the following bytes.
277
182
    OffsetWithinChar = 0;
278
182
  }
279
210
280
210
  return true;
281
210
}
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
570
Optional<size_t> ConstantAggregateBuilder::splitAt(CharUnits Pos) {
288
570
  if (Pos >= Size)
289
382
    return Offsets.size();
290
188
291
241
  
while (188
true) {
292
241
    auto FirstAfterPos = llvm::upper_bound(Offsets, Pos);
293
241
    if (FirstAfterPos == Offsets.begin())
294
0
      return 0;
295
241
296
    // If we already have an element starting at Pos, we're done.
297
241
    size_t LastAtOrBeforePosIndex = FirstAfterPos - Offsets.begin() - 1;
298
241
    if (Offsets[LastAtOrBeforePosIndex] == Pos)
299
184
      return LastAtOrBeforePosIndex;
300
57
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
53
306
    // Try to decompose it into smaller constants.
307
53
    if (!split(LastAtOrBeforePosIndex, Pos))
308
0
      return None;
309
53
  }
310
188
}
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
53
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
32
        isa<llvm::VectorType>(CA->getType())) {
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
19
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
4
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
4
    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
0
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
0
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
0
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
5.69k
    bool NaturalLayout, llvm::Type *DesiredTy, bool AllowOversized) {
402
5.69k
  ConstantAggregateBuilderUtils Utils(CGM);
403
5.69k
404
5.69k
  if (Elems.empty())
405
89
    return llvm::UndefValue::get(DesiredTy);
406
5.60k
407
5.60k
  auto Offset = [&](size_t I) 
{ return Offsets[I] - StartOffset; }465
;
408
5.60k
409
  // If we want an array type, see if all the elements are the same type and
410
  // appropriately spaced.
411
5.60k
  if (llvm::ArrayType *ATy = dyn_cast<llvm::ArrayType>(DesiredTy)) {
412
21
    assert(!AllowOversized && "oversized array emission not supported");
413
21
414
21
    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
74
424
      // All remaining elements must be the same type.
425
74
      if (Elems[I]->getType() != CommonType ||
426
72
          Offset(I) % ElemSize != 0) {
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
21
434
21
    if (CanEmitArray) {
435
19
      return EmitArrayConstant(CGM, ATy, CommonType, ATy->getNumElements(),
436
19
                               ArrayElements, Filler);
437
19
    }
438
5.59k
439
    // Can't emit as an array, carry on to emit as a struct.
440
21
  }
441
5.59k
442
5.59k
  CharUnits DesiredSize = Utils.getSize(DesiredTy);
443
5.59k
  CharUnits Align = CharUnits::One();
444
5.59k
  for (llvm::Constant *C : Elems)
445
11.2k
    Align = std::max(Align, Utils.getAlignment(C));
446
5.59k
  CharUnits AlignedSize = Size.alignTo(Align);
447
5.59k
448
5.59k
  bool Packed = false;
449
5.59k
  ArrayRef<llvm::Constant*> UnpackedElems = Elems;
450
5.59k
  llvm::SmallVector<llvm::Constant*, 32> UnpackedElemStorage;
451
5.59k
  if ((DesiredSize < AlignedSize && 
!AllowOversized116
) ||
452
5.47k
      DesiredSize.alignTo(Align) != DesiredSize) {
453
    // The natural layout would be the wrong size; force use of a packed layout.
454
113
    NaturalLayout = false;
455
113
    Packed = true;
456
5.47k
  } else if (DesiredSize > AlignedSize) {
457
    // The constant would be too small. Add padding to fix it.
458
359
    UnpackedElemStorage.assign(Elems.begin(), Elems.end());
459
359
    UnpackedElemStorage.push_back(Utils.getPadding(DesiredSize - Size));
460
359
    UnpackedElems = UnpackedElemStorage;
461
359
  }
462
5.59k
463
  // If we don't have a natural layout, insert padding as necessary.
464
  // As we go, double-check to see if we can actually just emit Elems
465
  // as a non-packed struct and do so opportunistically if possible.
466
5.59k
  llvm::SmallVector<llvm::Constant*, 32> PackedElems;
467
5.59k
  if (!NaturalLayout) {
468
156
    CharUnits SizeSoFar = CharUnits::Zero();
469
477
    for (size_t I = 0; I != Elems.size(); 
++I321
) {
470
321
      CharUnits Align = Utils.getAlignment(Elems[I]);
471
321
      CharUnits NaturalOffset = SizeSoFar.alignTo(Align);
472
321
      CharUnits DesiredOffset = Offset(I);
473
321
      assert(DesiredOffset >= SizeSoFar && "elements out of order");
474
321
475
321
      if (DesiredOffset != NaturalOffset)
476
106
        Packed = true;
477
321
      if (DesiredOffset != SizeSoFar)
478
3
        PackedElems.push_back(Utils.getPadding(DesiredOffset - SizeSoFar));
479
321
      PackedElems.push_back(Elems[I]);
480
321
      SizeSoFar = DesiredOffset + Utils.getSize(Elems[I]);
481
321
    }
482
    // If we're using the packed layout, pad it out to the desired size if
483
    // necessary.
484
156
    if (Packed) {
485
116
      assert((SizeSoFar <= DesiredSize || AllowOversized) &&
486
116
             "requested size is too small for contents");
487
116
      if (SizeSoFar < DesiredSize)
488
9
        PackedElems.push_back(Utils.getPadding(DesiredSize - SizeSoFar));
489
116
    }
490
156
  }
491
5.59k
492
5.59k
  llvm::StructType *STy = llvm::ConstantStruct::getTypeForElements(
493
5.47k
      CGM.getLLVMContext(), Packed ? 
PackedElems116
: UnpackedElems, Packed);
494
5.59k
495
  // Pick the type to use.  If the type is layout identical to the desired
496
  // type then use it, otherwise use whatever the builder produced for us.
497
5.59k
  if (llvm::StructType *DesiredSTy = dyn_cast<llvm::StructType>(DesiredTy)) {
498
5.58k
    if (DesiredSTy->isLayoutIdentical(STy))
499
4.67k
      STy = DesiredSTy;
500
5.58k
  }
501
5.59k
502
5.47k
  return llvm::ConstantStruct::get(STy, Packed ? 
PackedElems116
: UnpackedElems);
503
5.59k
}
504
505
void ConstantAggregateBuilder::condense(CharUnits Offset,
506
18
                                        llvm::Type *DesiredTy) {
507
18
  CharUnits Size = getSize(DesiredTy);
508
18
509
18
  llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
510
18
  if (!FirstElemToReplace)
511
0
    return;
512
18
  size_t First = *FirstElemToReplace;
513
18
514
18
  llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + Size);
515
18
  if (!LastElemToReplace)
516
0
    return;
517
18
  size_t Last = *LastElemToReplace;
518
18
519
18
  size_t Length = Last - First;
520
18
  if (Length == 0)
521
0
    return;
522
18
523
18
  if (Length == 1 && 
Offsets[First] == Offset4
&&
524
4
      getSize(Elems[First]) == Size) {
525
    // Re-wrap single element structs if necessary. Otherwise, leave any single
526
    // element constant of the right size alone even if it has the wrong type.
527
4
    auto *STy = dyn_cast<llvm::StructType>(DesiredTy);
528
4
    if (STy && STy->getNumElements() == 1 &&
529
4
        STy->getElementType(0) == Elems[First]->getType())
530
2
      Elems[First] = llvm::ConstantStruct::get(STy, Elems[First]);
531
4
    return;
532
4
  }
533
14
534
14
  llvm::Constant *Replacement = buildFrom(
535
14
      CGM, makeArrayRef(Elems).slice(First, Length),
536
14
      makeArrayRef(Offsets).slice(First, Length), Offset, getSize(DesiredTy),
537
14
      /*known to have natural layout=*/false, DesiredTy, false);
538
14
  replace(Elems, First, Last, {Replacement});
539
14
  replace(Offsets, First, Last, {Offset});
540
14
}
541
542
//===----------------------------------------------------------------------===//
543
//                            ConstStructBuilder
544
//===----------------------------------------------------------------------===//
545
546
class ConstStructBuilder {
547
  CodeGenModule &CGM;
548
  ConstantEmitter &Emitter;
549
  ConstantAggregateBuilder &Builder;
550
  CharUnits StartOffset;
551
552
public:
553
  static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
554
                                     InitListExpr *ILE, QualType StructTy);
555
  static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
556
                                     const APValue &Value, QualType ValTy);
557
  static bool UpdateStruct(ConstantEmitter &Emitter,
558
                           ConstantAggregateBuilder &Const, CharUnits Offset,
559
                           InitListExpr *Updater);
560
561
private:
562
  ConstStructBuilder(ConstantEmitter &Emitter,
563
                     ConstantAggregateBuilder &Builder, CharUnits StartOffset)
564
      : CGM(Emitter.CGM), Emitter(Emitter), Builder(Builder),
565
5.71k
        StartOffset(StartOffset) {}
566
567
  bool AppendField(const FieldDecl *Field, uint64_t FieldOffset,
568
                   llvm::Constant *InitExpr, bool AllowOverwrite = false);
569
570
  bool AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst,
571
                   bool AllowOverwrite = false);
572
573
  bool AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
574
                      llvm::ConstantInt *InitExpr, bool AllowOverwrite = false);
575
576
  bool Build(InitListExpr *ILE, bool AllowOverwrite);
577
  bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase,
578
             const CXXRecordDecl *VTableClass, CharUnits BaseOffset);
579
  llvm::Constant *Finalize(QualType Ty);
580
};
581
582
bool ConstStructBuilder::AppendField(
583
    const FieldDecl *Field, uint64_t FieldOffset, llvm::Constant *InitCst,
584
10.5k
    bool AllowOverwrite) {
585
10.5k
  const ASTContext &Context = CGM.getContext();
586
10.5k
587
10.5k
  CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
588
10.5k
589
10.5k
  return AppendBytes(FieldOffsetInChars, InitCst, AllowOverwrite);
590
10.5k
}
591
592
bool ConstStructBuilder::AppendBytes(CharUnits FieldOffsetInChars,
593
                                     llvm::Constant *InitCst,
594
10.8k
                                     bool AllowOverwrite) {
595
10.8k
  return Builder.add(InitCst, StartOffset + FieldOffsetInChars, AllowOverwrite);
596
10.8k
}
597
598
bool ConstStructBuilder::AppendBitField(
599
    const FieldDecl *Field, uint64_t FieldOffset, llvm::ConstantInt *CI,
600
210
    bool AllowOverwrite) {
601
210
  const CGRecordLayout &RL =
602
210
      CGM.getTypes().getCGRecordLayout(Field->getParent());
603
210
  const CGBitFieldInfo &Info = RL.getBitFieldInfo(Field);
604
210
  llvm::APInt FieldValue = CI->getValue();
605
210
606
  // Promote the size of FieldValue if necessary
607
  // FIXME: This should never occur, but currently it can because initializer
608
  // constants are cast to bool, and because clang is not enforcing bitfield
609
  // width limits.
610
210
  if (Info.Size > FieldValue.getBitWidth())
611
4
    FieldValue = FieldValue.zext(Info.Size);
612
210
613
  // Truncate the size of FieldValue to the bit field size.
614
210
  if (Info.Size < FieldValue.getBitWidth())
615
195
    FieldValue = FieldValue.trunc(Info.Size);
616
210
617
210
  return Builder.addBits(FieldValue,
618
210
                         CGM.getContext().toBits(StartOffset) + FieldOffset,
619
210
                         AllowOverwrite);
620
210
}
621
622
static bool EmitDesignatedInitUpdater(ConstantEmitter &Emitter,
623
                                      ConstantAggregateBuilder &Const,
624
                                      CharUnits Offset, QualType Type,
625
46
                                      InitListExpr *Updater) {
626
46
  if (Type->isRecordType())
627
25
    return ConstStructBuilder::UpdateStruct(Emitter, Const, Offset, Updater);
628
21
629
21
  auto CAT = Emitter.CGM.getContext().getAsConstantArrayType(Type);
630
21
  if (!CAT)
631
0
    return false;
632
21
  QualType ElemType = CAT->getElementType();
633
21
  CharUnits ElemSize = Emitter.CGM.getContext().getTypeSizeInChars(ElemType);
634
21
  llvm::Type *ElemTy = Emitter.CGM.getTypes().ConvertTypeForMem(ElemType);
635
21
636
21
  llvm::Constant *FillC = nullptr;
637
21
  if (Expr *Filler = Updater->getArrayFiller()) {
638
21
    if (!isa<NoInitExpr>(Filler)) {
639
3
      FillC = Emitter.tryEmitAbstractForMemory(Filler, ElemType);
640
3
      if (!FillC)
641
0
        return false;
642
21
    }
643
21
  }
644
21
645
21
  unsigned NumElementsToUpdate =
646
18
      FillC ? 
CAT->getSize().getZExtValue()3
: Updater->getNumInits();
647
111
  for (unsigned I = 0; I != NumElementsToUpdate; 
++I, Offset += ElemSize90
) {
648
90
    Expr *Init = nullptr;
649
90
    if (I < Updater->getNumInits())
650
78
      Init = Updater->getInit(I);
651
90
652
90
    if (!Init && 
FillC12
) {
653
12
      if (!Const.add(FillC, Offset, true))
654
0
        return false;
655
78
    } else if (!Init || isa<NoInitExpr>(Init)) {
656
52
      continue;
657
26
    } else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init)) {
658
4
      if (!EmitDesignatedInitUpdater(Emitter, Const, Offset, ElemType,
659
4
                                     ChildILE))
660
0
        return false;
661
      // Attempt to reduce the array element to a single constant if necessary.
662
4
      Const.condense(Offset, ElemTy);
663
22
    } else {
664
22
      llvm::Constant *Val = Emitter.tryEmitPrivateForMemory(Init, ElemType);
665
22
      if (!Const.add(Val, Offset, true))
666
0
        return false;
667
22
    }
668
90
  }
669
21
670
21
  return true;
671
21
}
672
673
2.42k
bool ConstStructBuilder::Build(InitListExpr *ILE, bool AllowOverwrite) {
674
2.42k
  RecordDecl *RD = ILE->getType()->castAs<RecordType>()->getDecl();
675
2.42k
  const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
676
2.42k
677
2.42k
  unsigned FieldNo = -1;
678
2.42k
  unsigned ElementNo = 0;
679
2.42k
680
  // Bail out if we have base classes. We could support these, but they only
681
  // arise in C++1z where we will have already constant folded most interesting
682
  // cases. FIXME: There are still a few more cases we can handle this way.
683
2.42k
  if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
684
123
    if (CXXRD->getNumBases())
685
6
      return false;
686
2.41k
687
5.39k
  
for (FieldDecl *Field : RD->fields())2.41k
{
688
5.39k
    ++FieldNo;
689
5.39k
690
    // If this is a union, skip all the fields that aren't being initialized.
691
5.39k
    if (RD->isUnion() &&
692
254
        !declaresSameEntity(ILE->getInitializedFieldInUnion(), Field))
693
125
      continue;
694
5.27k
695
    // Don't emit anonymous bitfields or zero-sized fields.
696
5.27k
    if (Field->isUnnamedBitfield() || 
Field->isZeroSize(CGM.getContext())5.24k
)
697
24
      continue;
698
5.24k
699
    // Get the initializer.  A struct can include fields without initializers,
700
    // we just use explicit null values for them.
701
5.24k
    Expr *Init = nullptr;
702
5.24k
    if (ElementNo < ILE->getNumInits())
703
5.20k
      Init = ILE->getInit(ElementNo++);
704
5.24k
    if (Init && 
isa<NoInitExpr>(Init)5.20k
)
705
15
      continue;
706
5.23k
707
    // When emitting a DesignatedInitUpdateExpr, a nested InitListExpr
708
    // represents additional overwriting of our current constant value, and not
709
    // a new constant to emit independently.
710
5.23k
    if (AllowOverwrite &&
711
27
        (Field->getType()->isArrayType() || 
Field->getType()->isRecordType()13
)) {
712
15
      if (auto *SubILE = dyn_cast<InitListExpr>(Init)) {
713
14
        CharUnits Offset = CGM.getContext().toCharUnitsFromBits(
714
14
            Layout.getFieldOffset(FieldNo));
715
14
        if (!EmitDesignatedInitUpdater(Emitter, Builder, StartOffset + Offset,
716
14
                                       Field->getType(), SubILE))
717
0
          return false;
718
        // If we split apart the field's value, try to collapse it down to a
719
        // single value now.
720
14
        Builder.condense(StartOffset + Offset,
721
14
                         CGM.getTypes().ConvertTypeForMem(Field->getType()));
722
14
        continue;
723
14
      }
724
15
    }
725
5.21k
726
5.21k
    llvm::Constant *EltInit =
727
5.17k
        Init ? Emitter.tryEmitPrivateForMemory(Init, Field->getType())
728
46
             : Emitter.emitNullForMemory(Field->getType());
729
5.21k
    if (!EltInit)
730
27
      return false;
731
5.19k
732
5.19k
    if (!Field->isBitField()) {
733
      // Handle non-bitfield members.
734
5.06k
      if (!AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit,
735
5.06k
                       AllowOverwrite))
736
0
        return false;
737
      // After emitting a non-empty field with [[no_unique_address]], we may
738
      // need to overwrite its tail padding.
739
5.06k
      if (Field->hasAttr<NoUniqueAddressAttr>())
740
0
        AllowOverwrite = true;
741
123
    } else {
742
      // Otherwise we have a bitfield.
743
123
      if (auto *CI = dyn_cast<llvm::ConstantInt>(EltInit)) {
744
120
        if (!AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI,
745
120
                            AllowOverwrite))
746
0
          return false;
747
3
      } else {
748
        // We are trying to initialize a bitfield with a non-trivial constant,
749
        // this must require run-time code.
750
3
        return false;
751
3
      }
752
123
    }
753
5.19k
  }
754
2.41k
755
2.38k
  return true;
756
2.41k
}
757
758
namespace {
759
struct BaseInfo {
760
  BaseInfo(const CXXRecordDecl *Decl, CharUnits Offset, unsigned Index)
761
412
    : Decl(Decl), Offset(Offset), Index(Index) {
762
412
  }
763
764
  const CXXRecordDecl *Decl;
765
  CharUnits Offset;
766
  unsigned Index;
767
768
63
  bool operator<(const BaseInfo &O) const { return Offset < O.Offset; }
769
};
770
}
771
772
bool ConstStructBuilder::Build(const APValue &Val, const RecordDecl *RD,
773
                               bool IsPrimaryBase,
774
                               const CXXRecordDecl *VTableClass,
775
3.70k
                               CharUnits Offset) {
776
3.70k
  const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
777
3.70k
778
3.70k
  if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
779
    // Add a vtable pointer, if we need one and it hasn't already been added.
780
3.70k
    if (Layout.hasOwnVFPtr()) {
781
343
      llvm::Constant *VTableAddressPoint =
782
343
          CGM.getCXXABI().getVTableAddressPointForConstExpr(
783
343
              BaseSubobject(CD, Offset), VTableClass);
784
343
      if (!AppendBytes(Offset, VTableAddressPoint))
785
0
        return false;
786
3.70k
    }
787
3.70k
788
    // Accumulate and sort bases, in order to visit them in address order, which
789
    // may not be the same as declaration order.
790
3.70k
    SmallVector<BaseInfo, 8> Bases;
791
3.70k
    Bases.reserve(CD->getNumBases());
792
3.70k
    unsigned BaseNo = 0;
793
3.70k
    for (CXXRecordDecl::base_class_const_iterator Base = CD->bases_begin(),
794
4.11k
         BaseEnd = CD->bases_end(); Base != BaseEnd; 
++Base, ++BaseNo412
) {
795
412
      assert(!Base->isVirtual() && "should not have virtual bases here");
796
412
      const CXXRecordDecl *BD = Base->getType()->getAsCXXRecordDecl();
797
412
      CharUnits BaseOffset = Layout.getBaseClassOffset(BD);
798
412
      Bases.push_back(BaseInfo(BD, BaseOffset, BaseNo));
799
412
    }
800
3.70k
    llvm::stable_sort(Bases);
801
3.70k
802
4.11k
    for (unsigned I = 0, N = Bases.size(); I != N; 
++I412
) {
803
412
      BaseInfo &Base = Bases[I];
804
412
805
412
      bool IsPrimaryBase = Layout.getPrimaryBase() == Base.Decl;
806
412
      Build(Val.getStructBase(Base.Index), Base.Decl, IsPrimaryBase,
807
412
            VTableClass, Offset + Base.Offset);
808
412
    }
809
3.70k
  }
810
3.70k
811
3.70k
  unsigned FieldNo = 0;
812
3.70k
  uint64_t OffsetBits = CGM.getContext().toBits(Offset);
813
3.70k
814
3.70k
  bool AllowOverwrite = false;
815
3.70k
  for (RecordDecl::field_iterator Field = RD->field_begin(),
816
9.73k
       FieldEnd = RD->field_end(); Field != FieldEnd; 
++Field, ++FieldNo6.02k
) {
817
    // If this is a union, skip all the fields that aren't being initialized.
818
6.02k
    if (RD->isUnion() && 
!declaresSameEntity(Val.getUnionField(), *Field)875
)
819
433
      continue;
820
5.59k
821
    // Don't emit anonymous bitfields or zero-sized fields.
822
5.59k
    if (Field->isUnnamedBitfield() || 
Field->isZeroSize(CGM.getContext())5.57k
)
823
43
      continue;
824
5.55k
825
    // Emit the value of the initializer.
826
5.55k
    const APValue &FieldValue =
827
5.10k
      RD->isUnion() ? 
Val.getUnionValue()442
: Val.getStructField(FieldNo);
828
5.55k
    llvm::Constant *EltInit =
829
5.55k
      Emitter.tryEmitPrivateForMemory(FieldValue, Field->getType());
830
5.55k
    if (!EltInit)
831
0
      return false;
832
5.55k
833
5.55k
    if (!Field->isBitField()) {
834
      // Handle non-bitfield members.
835
5.46k
      if (!AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
836
5.46k
                       EltInit, AllowOverwrite))
837
0
        return false;
838
      // After emitting a non-empty field with [[no_unique_address]], we may
839
      // need to overwrite its tail padding.
840
5.46k
      if (Field->hasAttr<NoUniqueAddressAttr>())
841
6
        AllowOverwrite = true;
842
90
    } else {
843
      // Otherwise we have a bitfield.
844
90
      if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
845
90
                          cast<llvm::ConstantInt>(EltInit), AllowOverwrite))
846
0
        return false;
847
90
    }
848
5.55k
  }
849
3.70k
850
3.70k
  return true;
851
3.70k
}
852
853
5.65k
llvm::Constant *ConstStructBuilder::Finalize(QualType Type) {
854
5.65k
  RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
855
5.65k
  llvm::Type *ValTy = CGM.getTypes().ConvertType(Type);
856
5.65k
  return Builder.build(ValTy, RD->hasFlexibleArrayMember());
857
5.65k
}
858
859
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
860
                                                InitListExpr *ILE,
861
2.39k
                                                QualType ValTy) {
862
2.39k
  ConstantAggregateBuilder Const(Emitter.CGM);
863
2.39k
  ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
864
2.39k
865
2.39k
  if (!Builder.Build(ILE, /*AllowOverwrite*/false))
866
36
    return nullptr;
867
2.36k
868
2.36k
  return Builder.Finalize(ValTy);
869
2.36k
}
870
871
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
872
                                                const APValue &Val,
873
3.29k
                                                QualType ValTy) {
874
3.29k
  ConstantAggregateBuilder Const(Emitter.CGM);
875
3.29k
  ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
876
3.29k
877
3.29k
  const RecordDecl *RD = ValTy->castAs<RecordType>()->getDecl();
878
3.29k
  const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
879
3.29k
  if (!Builder.Build(Val, RD, false, CD, CharUnits::Zero()))
880
0
    return nullptr;
881
3.29k
882
3.29k
  return Builder.Finalize(ValTy);
883
3.29k
}
884
885
bool ConstStructBuilder::UpdateStruct(ConstantEmitter &Emitter,
886
                                      ConstantAggregateBuilder &Const,
887
25
                                      CharUnits Offset, InitListExpr *Updater) {
888
25
  return ConstStructBuilder(Emitter, Const, Offset)
889
25
      .Build(Updater, /*AllowOverwrite*/ true);
890
25
}
891
892
//===----------------------------------------------------------------------===//
893
//                             ConstExprEmitter
894
//===----------------------------------------------------------------------===//
895
896
static ConstantAddress tryEmitGlobalCompoundLiteral(CodeGenModule &CGM,
897
                                                    CodeGenFunction *CGF,
898
17
                                              const CompoundLiteralExpr *E) {
899
17
  CharUnits Align = CGM.getContext().getTypeAlignInChars(E->getType());
900
17
  if (llvm::GlobalVariable *Addr =
901
2
          CGM.getAddrOfConstantCompoundLiteralIfEmitted(E))
902
2
    return ConstantAddress(Addr, Align);
903
15
904
15
  LangAS addressSpace = E->getType().getAddressSpace();
905
15
906
15
  ConstantEmitter emitter(CGM, CGF);
907
15
  llvm::Constant *C = emitter.tryEmitForInitializer(E->getInitializer(),
908
15
                                                    addressSpace, E->getType());
909
15
  if (!C) {
910
0
    assert(!E->isFileScope() &&
911
0
           "file-scope compound literal did not have constant initializer!");
912
0
    return ConstantAddress::invalid();
913
0
  }
914
15
915
15
  auto GV = new llvm::GlobalVariable(CGM.getModule(), C->getType(),
916
15
                                     CGM.isTypeConstant(E->getType(), true),
917
15
                                     llvm::GlobalValue::InternalLinkage,
918
15
                                     C, ".compoundliteral", nullptr,
919
15
                                     llvm::GlobalVariable::NotThreadLocal,
920
15
                    CGM.getContext().getTargetAddressSpace(addressSpace));
921
15
  emitter.finalize(GV);
922
15
  GV->setAlignment(Align.getAsAlign());
923
15
  CGM.setAddrOfConstantCompoundLiteral(E, GV);
924
15
  return ConstantAddress(GV, Align);
925
15
}
926
927
static llvm::Constant *
928
EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
929
                  llvm::Type *CommonElementType, unsigned ArrayBound,
930
                  SmallVectorImpl<llvm::Constant *> &Elements,
931
3.67k
                  llvm::Constant *Filler) {
932
  // Figure out how long the initial prefix of non-zero elements is.
933
3.67k
  unsigned NonzeroLength = ArrayBound;
934
3.67k
  if (Elements.size() < NonzeroLength && 
Filler->isNullValue()695
)
935
690
    NonzeroLength = Elements.size();
936
3.67k
  if (NonzeroLength == Elements.size()) {
937
4.16k
    while (NonzeroLength > 0 && 
Elements[NonzeroLength - 1]->isNullValue()3.58k
)
938
501
      --NonzeroLength;
939
3.66k
  }
940
3.67k
941
3.67k
  if (NonzeroLength == 0)
942
585
    return llvm::ConstantAggregateZero::get(DesiredType);
943
3.08k
944
  // Add a zeroinitializer array filler if we have lots of trailing zeroes.
945
3.08k
  unsigned TrailingZeroes = ArrayBound - NonzeroLength;
946
3.08k
  if (TrailingZeroes >= 8) {
947
41
    assert(Elements.size() >= NonzeroLength &&
948
41
           "missing initializer for non-zero element");
949
41
950
    // If all the elements had the same type up to the trailing zeroes, emit a
951
    // struct of two arrays (the nonzero data and the zeroinitializer).
952
41
    if (CommonElementType && 
NonzeroLength >= 840
) {
953
13
      llvm::Constant *Initial = llvm::ConstantArray::get(
954
13
          llvm::ArrayType::get(CommonElementType, NonzeroLength),
955
13
          makeArrayRef(Elements).take_front(NonzeroLength));
956
13
      Elements.resize(2);
957
13
      Elements[0] = Initial;
958
28
    } else {
959
28
      Elements.resize(NonzeroLength + 1);
960
28
    }
961
41
962
41
    auto *FillerType =
963
40
        CommonElementType ? CommonElementType : 
DesiredType->getElementType()1
;
964
41
    FillerType = llvm::ArrayType::get(FillerType, TrailingZeroes);
965
41
    Elements.back() = llvm::ConstantAggregateZero::get(FillerType);
966
41
    CommonElementType = nullptr;
967
3.04k
  } else if (Elements.size() != ArrayBound) {
968
    // Otherwise pad to the right size with the filler if necessary.
969
153
    Elements.resize(ArrayBound, Filler);
970
153
    if (Filler->getType() != CommonElementType)
971
5
      CommonElementType = nullptr;
972
153
  }
973
3.08k
974
  // If all elements have the same type, just emit an array constant.
975
3.08k
  if (CommonElementType)
976
3.03k
    return llvm::ConstantArray::get(
977
3.03k
        llvm::ArrayType::get(CommonElementType, ArrayBound), Elements);
978
51
979
  // We have mixed types. Use a packed struct.
980
51
  llvm::SmallVector<llvm::Type *, 16> Types;
981
51
  Types.reserve(Elements.size());
982
51
  for (llvm::Constant *Elt : Elements)
983
161
    Types.push_back(Elt->getType());
984
51
  llvm::StructType *SType =
985
51
      llvm::StructType::get(CGM.getLLVMContext(), Types, true);
986
51
  return llvm::ConstantStruct::get(SType, Elements);
987
51
}
988
989
// This class only needs to handle arrays, structs and unions. Outside C++11
990
// mode, we don't currently constant fold those types.  All other types are
991
// handled by constant folding.
992
//
993
// Constant folding is currently missing support for a few features supported
994
// here: CK_ToUnion, CK_ReinterpretMemberPointer, and DesignatedInitUpdateExpr.
995
class ConstExprEmitter :
996
  public StmtVisitor<ConstExprEmitter, llvm::Constant*, QualType> {
997
  CodeGenModule &CGM;
998
  ConstantEmitter &Emitter;
999
  llvm::LLVMContext &VMContext;
1000
public:
1001
  ConstExprEmitter(ConstantEmitter &emitter)
1002
23.1k
    : CGM(emitter.CGM), Emitter(emitter), VMContext(CGM.getLLVMContext()) {
1003
23.1k
  }
1004
1005
  //===--------------------------------------------------------------------===//
1006
  //                            Visitor Methods
1007
  //===--------------------------------------------------------------------===//
1008
1009
14.1k
  llvm::Constant *VisitStmt(Stmt *S, QualType T) {
1010
14.1k
    return nullptr;
1011
14.1k
  }
1012
1013
16
  llvm::Constant *VisitConstantExpr(ConstantExpr *CE, QualType T) {
1014
16
    if (llvm::Constant *Result = Emitter.tryEmitConstantExpr(CE))
1015
0
      return Result;
1016
16
    return Visit(CE->getSubExpr(), T);
1017
16
  }
1018
1019
141
  llvm::Constant *VisitParenExpr(ParenExpr *PE, QualType T) {
1020
141
    return Visit(PE->getSubExpr(), T);
1021
141
  }
1022
1023
  llvm::Constant *
1024
  VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *PE,
1025
0
                                    QualType T) {
1026
0
    return Visit(PE->getReplacement(), T);
1027
0
  }
1028
1029
  llvm::Constant *VisitGenericSelectionExpr(GenericSelectionExpr *GE,
1030
1
                                            QualType T) {
1031
1
    return Visit(GE->getResultExpr(), T);
1032
1
  }
1033
1034
1
  llvm::Constant *VisitChooseExpr(ChooseExpr *CE, QualType T) {
1035
1
    return Visit(CE->getChosenSubExpr(), T);
1036
1
  }
1037
1038
35
  llvm::Constant *VisitCompoundLiteralExpr(CompoundLiteralExpr *E, QualType T) {
1039
35
    return Visit(E->getInitializer(), T);
1040
35
  }
1041
1042
5.44k
  llvm::Constant *VisitCastExpr(CastExpr *E, QualType destType) {
1043
5.44k
    if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E))
1044
783
      CGM.EmitExplicitCastExprType(ECE, Emitter.CGF);
1045
5.44k
    Expr *subExpr = E->getSubExpr();
1046
5.44k
1047
5.44k
    switch (E->getCastKind()) {
1048
4
    case CK_ToUnion: {
1049
      // GCC cast to union extension
1050
4
      assert(E->getType()->isUnionType() &&
1051
4
             "Destination type is not union type!");
1052
4
1053
4
      auto field = E->getTargetUnionField();
1054
4
1055
4
      auto C = Emitter.tryEmitPrivateForMemory(subExpr, field->getType());
1056
4
      if (!C) 
return nullptr0
;
1057
4
1058
4
      auto destTy = ConvertType(destType);
1059
4
      if (C->getType() == destTy) 
return C0
;
1060
4
1061
      // Build a struct with the union sub-element as the first member,
1062
      // and padded to the appropriate size.
1063
4
      SmallVector<llvm::Constant*, 2> Elts;
1064
4
      SmallVector<llvm::Type*, 2> Types;
1065
4
      Elts.push_back(C);
1066
4
      Types.push_back(C->getType());
1067
4
      unsigned CurSize = CGM.getDataLayout().getTypeAllocSize(C->getType());
1068
4
      unsigned TotalSize = CGM.getDataLayout().getTypeAllocSize(destTy);
1069
4
1070
4
      assert(CurSize <= TotalSize && "Union size mismatch!");
1071
4
      if (unsigned NumPadBytes = TotalSize - CurSize) {
1072
2
        llvm::Type *Ty = CGM.Int8Ty;
1073
2
        if (NumPadBytes > 1)
1074
2
          Ty = llvm::ArrayType::get(Ty, NumPadBytes);
1075
2
1076
2
        Elts.push_back(llvm::UndefValue::get(Ty));
1077
2
        Types.push_back(Ty);
1078
2
      }
1079
4
1080
4
      llvm::StructType *STy = llvm::StructType::get(VMContext, Types, false);
1081
4
      return llvm::ConstantStruct::get(STy, Elts);
1082
4
    }
1083
4
1084
0
    case CK_AddressSpaceConversion: {
1085
0
      auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
1086
0
      if (!C) return nullptr;
1087
0
      LangAS destAS = E->getType()->getPointeeType().getAddressSpace();
1088
0
      LangAS srcAS = subExpr->getType()->getPointeeType().getAddressSpace();
1089
0
      llvm::Type *destTy = ConvertType(E->getType());
1090
0
      return CGM.getTargetCodeGenInfo().performAddrSpaceCast(CGM, C, srcAS,
1091
0
                                                             destAS, destTy);
1092
0
    }
1093
0
1094
4.99k
    case CK_LValueToRValue:
1095
4.99k
    case CK_AtomicToNonAtomic:
1096
4.99k
    case CK_NonAtomicToAtomic:
1097
4.99k
    case CK_NoOp:
1098
4.99k
    case CK_ConstructorConversion:
1099
4.99k
      return Visit(subExpr, destType);
1100
4.99k
1101
0
    case CK_IntToOCLSampler:
1102
0
      llvm_unreachable("global sampler variables are not generated");
1103
4.99k
1104
0
    case CK_Dependent: llvm_unreachable("saw dependent cast!");
1105
4.99k
1106
0
    case CK_BuiltinFnToFnPtr:
1107
0
      llvm_unreachable("builtin functions are handled elsewhere");
1108
4.99k
1109
57
    case CK_ReinterpretMemberPointer:
1110
57
    case CK_DerivedToBaseMemberPointer:
1111
57
    case CK_BaseToDerivedMemberPointer: {
1112
57
      auto C = Emitter.tryEmitPrivate(subExpr, subExpr->getType());
1113
57
      if (!C) 
return nullptr0
;
1114
57
      return CGM.getCXXABI().EmitMemberPointerConversion(E, C);
1115
57
    }
1116
57
1117
    // These will never be supported.
1118
34
    case CK_ObjCObjectLValueCast:
1119
34
    case CK_ARCProduceObject:
1120
34
    case CK_ARCConsumeObject:
1121
34
    case CK_ARCReclaimReturnedObject:
1122
34
    case CK_ARCExtendBlockObject:
1123
34
    case CK_CopyAndAutoreleaseBlockObject:
1124
34
      return nullptr;
1125
34
1126
    // These don't need to be handled here because Evaluate knows how to
1127
    // evaluate them in the cases where they can be folded.
1128
351
    case CK_BitCast:
1129
351
    case CK_ToVoid:
1130
351
    case CK_Dynamic:
1131
351
    case CK_LValueBitCast:
1132
351
    case CK_LValueToRValueBitCast:
1133
351
    case CK_NullToMemberPointer:
1134
351
    case CK_UserDefinedConversion:
1135
351
    case CK_CPointerToObjCPointerCast:
1136
351
    case CK_BlockPointerToObjCPointerCast:
1137
351
    case CK_AnyPointerToBlockPointerCast:
1138
351
    case CK_ArrayToPointerDecay:
1139
351
    case CK_FunctionToPointerDecay:
1140
351
    case CK_BaseToDerived:
1141
351
    case CK_DerivedToBase:
1142
351
    case CK_UncheckedDerivedToBase:
1143
351
    case CK_MemberPointerToBoolean:
1144
351
    case CK_VectorSplat:
1145
351
    case CK_FloatingRealToComplex:
1146
351
    case CK_FloatingComplexToReal:
1147
351
    case CK_FloatingComplexToBoolean:
1148
351
    case CK_FloatingComplexCast:
1149
351
    case CK_FloatingComplexToIntegralComplex:
1150
351
    case CK_IntegralRealToComplex:
1151
351
    case CK_IntegralComplexToReal:
1152
351
    case CK_IntegralComplexToBoolean:
1153
351
    case CK_IntegralComplexCast:
1154
351
    case CK_IntegralComplexToFloatingComplex:
1155
351
    case CK_PointerToIntegral:
1156
351
    case CK_PointerToBoolean:
1157
351
    case CK_NullToPointer:
1158
351
    case CK_IntegralCast:
1159
351
    case CK_BooleanToSignedIntegral:
1160
351
    case CK_IntegralToPointer:
1161
351
    case CK_IntegralToBoolean:
1162
351
    case CK_IntegralToFloating:
1163
351
    case CK_FloatingToIntegral:
1164
351
    case CK_FloatingToBoolean:
1165
351
    case CK_FloatingCast:
1166
351
    case CK_FixedPointCast:
1167
351
    case CK_FixedPointToBoolean:
1168
351
    case CK_FixedPointToIntegral:
1169
351
    case CK_IntegralToFixedPoint:
1170
351
    case CK_ZeroToOCLOpaqueType:
1171
351
      return nullptr;
1172
0
    }
1173
0
    llvm_unreachable("Invalid CastKind");
1174
0
  }
1175
1176
3
  llvm::Constant *VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE, QualType T) {
1177
    // No need for a DefaultInitExprScope: we don't handle 'this' in a
1178
    // constant expression.
1179
3
    return Visit(DIE->getExpr(), T);
1180
3
  }
1181
1182
738
  llvm::Constant *VisitExprWithCleanups(ExprWithCleanups *E, QualType T) {
1183
738
    return Visit(E->getSubExpr(), T);
1184
738
  }
1185
1186
  llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
1187
137
                                                QualType T) {
1188
137
    return Visit(E->getSubExpr(), T);
1189
137
  }
1190
1191
1.14k
  llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) {
1192
1.14k
    auto *CAT = CGM.getContext().getAsConstantArrayType(ILE->getType());
1193
1.14k
    assert(CAT && "can't emit array init for non-constant-bound array");
1194
1.14k
    unsigned NumInitElements = ILE->getNumInits();
1195
1.14k
    unsigned NumElements = CAT->getSize().getZExtValue();
1196
1.14k
1197
    // Initialising an array requires us to automatically
1198
    // initialise any elements that have not been initialised explicitly
1199
1.14k
    unsigned NumInitableElts = std::min(NumInitElements, NumElements);
1200
1.14k
1201
1.14k
    QualType EltType = CAT->getElementType();
1202
1.14k
1203
    // Initialize remaining array elements.
1204
1.14k
    llvm::Constant *fillC = nullptr;
1205
1.14k
    if (Expr *filler = ILE->getArrayFiller()) {
1206
140
      fillC = Emitter.tryEmitAbstractForMemory(filler, EltType);
1207
140
      if (!fillC)
1208
8
        return nullptr;
1209
1.13k
    }
1210
1.13k
1211
    // Copy initializer elements.
1212
1.13k
    SmallVector<llvm::Constant*, 16> Elts;
1213
1.13k
    if (fillC && 
fillC->isNullValue()132
)
1214
132
      Elts.reserve(NumInitableElts + 1);
1215
1.00k
    else
1216
1.00k
      Elts.reserve(NumElements);
1217
1.13k
1218
1.13k
    llvm::Type *CommonElementType = nullptr;
1219
6.90k
    for (unsigned i = 0; i < NumInitableElts; 
++i5.76k
) {
1220
6.15k
      Expr *Init = ILE->getInit(i);
1221
6.15k
      llvm::Constant *C = Emitter.tryEmitPrivateForMemory(Init, EltType);
1222
6.15k
      if (!C)
1223
388
        return nullptr;
1224
5.76k
      if (i == 0)
1225
729
        CommonElementType = C->getType();
1226
5.03k
      else if (C->getType() != CommonElementType)
1227
4
        CommonElementType = nullptr;
1228
5.76k
      Elts.push_back(C);
1229
5.76k
    }
1230
1.13k
1231
748
    llvm::ArrayType *Desired =
1232
748
        cast<llvm::ArrayType>(CGM.getTypes().ConvertType(ILE->getType()));
1233
748
    return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
1234
748
                             fillC);
1235
1.13k
  }
1236
1237
2.39k
  llvm::Constant *EmitRecordInitialization(InitListExpr *ILE, QualType T) {
1238
2.39k
    return ConstStructBuilder::BuildStruct(Emitter, ILE, T);
1239
2.39k
  }
1240
1241
  llvm::Constant *VisitImplicitValueInitExpr(ImplicitValueInitExpr* E,
1242
58
                                             QualType T) {
1243
58
    return CGM.EmitNullConstant(T);
1244
58
  }
1245
1246
3.55k
  llvm::Constant *VisitInitListExpr(InitListExpr *ILE, QualType T) {
1247
3.55k
    if (ILE->isTransparent())
1248
15
      return Visit(ILE->getInit(0), T);
1249
3.54k
1250
3.54k
    if (ILE->getType()->isArrayType())
1251
1.14k
      return EmitArrayInitialization(ILE, T);
1252
2.39k
1253
2.39k
    if (ILE->getType()->isRecordType())
1254
2.39k
      return EmitRecordInitialization(ILE, T);
1255
0
1256
0
    return nullptr;
1257
0
  }
1258
1259
  llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E,
1260
28
                                                QualType destType) {
1261
28
    auto C = Visit(E->getBase(), destType);
1262
28
    if (!C)
1263
0
      return nullptr;
1264
28
1265
28
    ConstantAggregateBuilder Const(CGM);
1266
28
    Const.add(C, CharUnits::Zero(), false);
1267
28
1268
28
    if (!EmitDesignatedInitUpdater(Emitter, Const, CharUnits::Zero(), destType,
1269
28
                                   E->getUpdater()))
1270
0
      return nullptr;
1271
28
1272
28
    llvm::Type *ValTy = CGM.getTypes().ConvertType(destType);
1273
28
    bool HasFlexibleArray = false;
1274
28
    if (auto *RT = destType->getAs<RecordType>())
1275
20
      HasFlexibleArray = RT->getDecl()->hasFlexibleArrayMember();
1276
28
    return Const.build(ValTy, HasFlexibleArray);
1277
28
  }
1278
1279
4.97k
  llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) {
1280
4.97k
    if (!E->getConstructor()->isTrivial())
1281
4.79k
      return nullptr;
1282
181
1283
    // Only default and copy/move constructors can be trivial.
1284
181
    if (E->getNumArgs()) {
1285
179
      assert(E->getNumArgs() == 1 && "trivial ctor with > 1 argument");
1286
179
      assert(E->getConstructor()->isCopyOrMoveConstructor() &&
1287
179
             "trivial ctor has argument but isn't a copy/move ctor");
1288
179
1289
179
      Expr *Arg = E->getArg(0);
1290
179
      assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) &&
1291
179
             "argument to copy ctor is of wrong type");
1292
179
1293
179
      return Visit(Arg, Ty);
1294
179
    }
1295
2
1296
2
    return CGM.EmitNullConstant(Ty);
1297
2
  }
1298
1299
91
  llvm::Constant *VisitStringLiteral(StringLiteral *E, QualType T) {
1300
    // This is a string literal initializing an array in an initializer.
1301
91
    return CGM.GetConstantArrayFromStringLiteral(E);
1302
91
  }
1303
1304
36
  llvm::Constant *VisitObjCEncodeExpr(ObjCEncodeExpr *E, QualType T) {
1305
    // This must be an @encode initializing an array in a static initializer.
1306
    // Don't emit it as the address of the string, emit the string data itself
1307
    // as an inline array.
1308
36
    std::string Str;
1309
36
    CGM.getContext().getObjCEncodingForType(E->getEncodedType(), Str);
1310
36
    const ConstantArrayType *CAT = CGM.getContext().getAsConstantArrayType(T);
1311
36
1312
    // Resize the string to the right size, adding zeros at the end, or
1313
    // truncating as needed.
1314
36
    Str.resize(CAT->getSize().getZExtValue(), '\0');
1315
36
    return llvm::ConstantDataArray::getString(VMContext, Str, false);
1316
36
  }
1317
1318
1
  llvm::Constant *VisitUnaryExtension(const UnaryOperator *E, QualType T) {
1319
1
    return Visit(E->getSubExpr(), T);
1320
1
  }
1321
1322
  // Utility methods
1323
4
  llvm::Type *ConvertType(QualType T) {
1324
4
    return CGM.getTypes().ConvertType(T);
1325
4
  }
1326
};
1327
1328
}  // end anonymous namespace.
1329
1330
llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C,
1331
24.5k
                                                        AbstractState saved) {
1332
24.5k
  Abstract = saved.OldValue;
1333
24.5k
1334
24.5k
  assert(saved.OldPlaceholdersSize == PlaceholderAddresses.size() &&
1335
24.5k
         "created a placeholder while doing an abstract emission?");
1336
24.5k
1337
  // No validation necessary for now.
1338
  // No cleanup to do for now.
1339
24.5k
  return C;
1340
24.5k
}
1341
1342
llvm::Constant *
1343
14.8k
ConstantEmitter::tryEmitAbstractForInitializer(const VarDecl &D) {
1344
14.8k
  auto state = pushAbstract();
1345
14.8k
  auto C = tryEmitPrivateForVarInit(D);
1346
14.8k
  return validateAndPopAbstract(C, state);
1347
14.8k
}
1348
1349
llvm::Constant *
1350
554
ConstantEmitter::tryEmitAbstract(const Expr *E, QualType destType) {
1351
554
  auto state = pushAbstract();
1352
554
  auto C = tryEmitPrivate(E, destType);
1353
554
  return validateAndPopAbstract(C, state);
1354
554
}
1355
1356
llvm::Constant *
1357
556
ConstantEmitter::tryEmitAbstract(const APValue &value, QualType destType) {
1358
556
  auto state = pushAbstract();
1359
556
  auto C = tryEmitPrivate(value, destType);
1360
556
  return validateAndPopAbstract(C, state);
1361
556
}
1362
1363
601
llvm::Constant *ConstantEmitter::tryEmitConstantExpr(const ConstantExpr *CE) {
1364
601
  if (!CE->hasAPValueResult())
1365
125
    return nullptr;
1366
476
  const Expr *Inner = CE->getSubExpr()->IgnoreImplicit();
1367
476
  QualType RetType;
1368
476
  if (auto *Call = dyn_cast<CallExpr>(Inner))
1369
20
    RetType = Call->getCallReturnType(CGF->getContext());
1370
456
  else if (auto *Ctor = dyn_cast<CXXConstructExpr>(Inner))
1371
2
    RetType = Ctor->getType();
1372
476
  llvm::Constant *Res =
1373
476
      emitAbstract(CE->getBeginLoc(), CE->getAPValueResult(), RetType);
1374
476
  return Res;
1375
476
}
1376
1377
llvm::Constant *
1378
308
ConstantEmitter::emitAbstract(const Expr *E, QualType destType) {
1379
308
  auto state = pushAbstract();
1380
308
  auto C = tryEmitPrivate(E, destType);
1381
308
  C = validateAndPopAbstract(C, state);
1382
308
  if (!C) {
1383
0
    CGM.Error(E->getExprLoc(),
1384
0
              "internal error: could not emit constant value \"abstractly\"");
1385
0
    C = CGM.EmitNullConstant(destType);
1386
0
  }
1387
308
  return C;
1388
308
}
1389
1390
llvm::Constant *
1391
ConstantEmitter::emitAbstract(SourceLocation loc, const APValue &value,
1392
8.23k
                              QualType destType) {
1393
8.23k
  auto state = pushAbstract();
1394
8.23k
  auto C = tryEmitPrivate(value, destType);
1395
8.23k
  C = validateAndPopAbstract(C, state);
1396
8.23k
  if (!C) {
1397
0
    CGM.Error(loc,
1398
0
              "internal error: could not emit constant value \"abstractly\"");
1399
0
    C = CGM.EmitNullConstant(destType);
1400
0
  }
1401
8.23k
  return C;
1402
8.23k
}
1403
1404
24.0k
llvm::Constant *ConstantEmitter::tryEmitForInitializer(const VarDecl &D) {
1405
24.0k
  initializeNonAbstract(D.getType().getAddressSpace());
1406
24.0k
  return markIfFailed(tryEmitPrivateForVarInit(D));
1407
24.0k
}
1408
1409
llvm::Constant *ConstantEmitter::tryEmitForInitializer(const Expr *E,
1410
                                                       LangAS destAddrSpace,
1411
99
                                                       QualType destType) {
1412
99
  initializeNonAbstract(destAddrSpace);
1413
99
  return markIfFailed(tryEmitPrivateForMemory(E, destType));
1414
99
}
1415
1416
llvm::Constant *ConstantEmitter::emitForInitializer(const APValue &value,
1417
                                                    LangAS destAddrSpace,
1418
142
                                                    QualType destType) {
1419
142
  initializeNonAbstract(destAddrSpace);
1420
142
  auto C = tryEmitPrivateForMemory(value, destType);
1421
142
  assert(C && "couldn't emit constant value non-abstractly?");
1422
142
  return C;
1423
142
}
1424
1425
0
llvm::GlobalValue *ConstantEmitter::getCurrentAddrPrivate() {
1426
0
  assert(!Abstract && "cannot get current address for abstract constant");
1427
0
1428
0
1429
0
1430
  // Make an obviously ill-formed global that should blow up compilation
1431
  // if it survives.
1432
0
  auto global = new llvm::GlobalVariable(CGM.getModule(), CGM.Int8Ty, true,
1433
0
                                         llvm::GlobalValue::PrivateLinkage,
1434
0
                                         /*init*/ nullptr,
1435
0
                                         /*name*/ "",
1436
0
                                         /*before*/ nullptr,
1437
0
                                         llvm::GlobalVariable::NotThreadLocal,
1438
0
                                         CGM.getContext().getTargetAddressSpace(DestAddressSpace));
1439
0
1440
0
  PlaceholderAddresses.push_back(std::make_pair(nullptr, global));
1441
0
1442
0
  return global;
1443
0
}
1444
1445
void ConstantEmitter::registerCurrentAddrPrivate(llvm::Constant *signal,
1446
0
                                           llvm::GlobalValue *placeholder) {
1447
0
  assert(!PlaceholderAddresses.empty());
1448
0
  assert(PlaceholderAddresses.back().first == nullptr);
1449
0
  assert(PlaceholderAddresses.back().second == placeholder);
1450
0
  PlaceholderAddresses.back().first = signal;
1451
0
}
1452
1453
namespace {
1454
  struct ReplacePlaceholders {
1455
    CodeGenModule &CGM;
1456
1457
    /// The base address of the global.
1458
    llvm::Constant *Base;
1459
    llvm::Type *BaseValueTy = nullptr;
1460
1461
    /// The placeholder addresses that were registered during emission.
1462
    llvm::DenseMap<llvm::Constant*, llvm::GlobalVariable*> PlaceholderAddresses;
1463
1464
    /// The locations of the placeholder signals.
1465
    llvm::DenseMap<llvm::GlobalVariable*, llvm::Constant*> Locations;
1466
1467
    /// The current index stack.  We use a simple unsigned stack because
1468
    /// we assume that placeholders will be relatively sparse in the
1469
    /// initializer, but we cache the index values we find just in case.
1470
    llvm::SmallVector<unsigned, 8> Indices;
1471
    llvm::SmallVector<llvm::Constant*, 8> IndexValues;
1472
1473
    ReplacePlaceholders(CodeGenModule &CGM, llvm::Constant *base,
1474
                        ArrayRef<std::pair<llvm::Constant*,
1475
                                           llvm::GlobalVariable*>> addresses)
1476
        : CGM(CGM), Base(base),
1477
0
          PlaceholderAddresses(addresses.begin(), addresses.end()) {
1478
0
    }
1479
1480
0
    void replaceInInitializer(llvm::Constant *init) {
1481
      // Remember the type of the top-most initializer.
1482
0
      BaseValueTy = init->getType();
1483
0
1484
      // Initialize the stack.
1485
0
      Indices.push_back(0);
1486
0
      IndexValues.push_back(nullptr);
1487
0
1488
      // Recurse into the initializer.
1489
0
      findLocations(init);
1490
0
1491
      // Check invariants.
1492
0
      assert(IndexValues.size() == Indices.size() && "mismatch");
1493
0
      assert(Indices.size() == 1 && "didn't pop all indices");
1494
0
1495
      // Do the replacement; this basically invalidates 'init'.
1496
0
      assert(Locations.size() == PlaceholderAddresses.size() &&
1497
0
             "missed a placeholder?");
1498
0
1499
      // We're iterating over a hashtable, so this would be a source of
1500
      // non-determinism in compiler output *except* that we're just
1501
      // messing around with llvm::Constant structures, which never itself
1502
      // does anything that should be visible in compiler output.
1503
0
      for (auto &entry : Locations) {
1504
0
        assert(entry.first->getParent() == nullptr && "not a placeholder!");
1505
0
        entry.first->replaceAllUsesWith(entry.second);
1506
0
        entry.first->eraseFromParent();
1507
0
      }
1508
0
    }
1509
1510
  private:
1511
0
    void findLocations(llvm::Constant *init) {
1512
      // Recurse into aggregates.
1513
0
      if (auto agg = dyn_cast<llvm::ConstantAggregate>(init)) {
1514
0
        for (unsigned i = 0, e = agg->getNumOperands(); i != e; ++i) {
1515
0
          Indices.push_back(i);
1516
0
          IndexValues.push_back(nullptr);
1517
0
1518
0
          findLocations(agg->getOperand(i));
1519
0
1520
0
          IndexValues.pop_back();
1521
0
          Indices.pop_back();
1522
0
        }
1523
0
        return;
1524
0
      }
1525
0
1526
      // Otherwise, check for registered constants.
1527
0
      while (true) {
1528
0
        auto it = PlaceholderAddresses.find(init);
1529
0
        if (it != PlaceholderAddresses.end()) {
1530
0
          setLocation(it->second);
1531
0
          break;
1532
0
        }
1533
0
1534
        // Look through bitcasts or other expressions.
1535
0
        if (auto expr = dyn_cast<llvm::ConstantExpr>(init)) {
1536
0
          init = expr->getOperand(0);
1537
0
        } else {
1538
0
          break;
1539
0
        }
1540
0
      }
1541
0
    }
1542
1543
0
    void setLocation(llvm::GlobalVariable *placeholder) {
1544
0
      assert(Locations.find(placeholder) == Locations.end() &&
1545
0
             "already found location for placeholder!");
1546
0
1547
      // Lazily fill in IndexValues with the values from Indices.
1548
      // We do this in reverse because we should always have a strict
1549
      // prefix of indices from the start.
1550
0
      assert(Indices.size() == IndexValues.size());
1551
0
      for (size_t i = Indices.size() - 1; i != size_t(-1); --i) {
1552
0
        if (IndexValues[i]) {
1553
0
#ifndef NDEBUG
1554
0
          for (size_t j = 0; j != i + 1; ++j) {
1555
0
            assert(IndexValues[j] &&
1556
0
                   isa<llvm::ConstantInt>(IndexValues[j]) &&
1557
0
                   cast<llvm::ConstantInt>(IndexValues[j])->getZExtValue()
1558
0
                     == Indices[j]);
1559
0
          }
1560
0
#endif
1561
0
          break;
1562
0
        }
1563
0
1564
0
        IndexValues[i] = llvm::ConstantInt::get(CGM.Int32Ty, Indices[i]);
1565
0
      }
1566
0
1567
      // Form a GEP and then bitcast to the placeholder type so that the
1568
      // replacement will succeed.
1569
0
      llvm::Constant *location =
1570
0
        llvm::ConstantExpr::getInBoundsGetElementPtr(BaseValueTy,
1571
0
                                                     Base, IndexValues);
1572
0
      location = llvm::ConstantExpr::getBitCast(location,
1573
0
                                                placeholder->getType());
1574
0
1575
0
      Locations.insert({placeholder, location});
1576
0
    }
1577
  };
1578
}
1579
1580
17.0k
void ConstantEmitter::finalize(llvm::GlobalVariable *global) {
1581
17.0k
  assert(InitializedNonAbstract &&
1582
17.0k
         "finalizing emitter that was used for abstract emission?");
1583
17.0k
  assert(!Finalized && "finalizing emitter multiple times");
1584
17.0k
  assert(global->getInitializer());
1585
17.0k
1586
  // Note that we might also be Failed.
1587
17.0k
  Finalized = true;
1588
17.0k
1589
17.0k
  if (!PlaceholderAddresses.empty()) {
1590
0
    ReplacePlaceholders(CGM, global, PlaceholderAddresses)
1591
0
      .replaceInInitializer(global->getInitializer());
1592
0
    PlaceholderAddresses.clear(); // satisfy
1593
0
  }
1594
17.0k
}
1595
1596
48.2k
ConstantEmitter::~ConstantEmitter() {
1597
48.2k
  assert((!InitializedNonAbstract || Finalized || Failed) &&
1598
48.2k
         "not finalized after being initialized for non-abstract emission");
1599
48.2k
  assert(PlaceholderAddresses.empty() && "unhandled placeholders");
1600
48.2k
}
1601
1602
61.6k
static QualType getNonMemoryType(CodeGenModule &CGM, QualType type) {
1603
61.6k
  if (auto AT = type->getAs<AtomicType>()) {
1604
99
    return CGM.getContext().getQualifiedType(AT->getValueType(),
1605
99
                                             type.getQualifiers());
1606
99
  }
1607
61.5k
  return type;
1608
61.5k
}
1609
1610
38.8k
llvm::Constant *ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &D) {
1611
  // Make a quick check if variable can be default NULL initialized
1612
  // and avoid going through rest of code which may do, for c++11,
1613
  // initialization of memory to all NULLs.
1614
38.8k
  if (!D.hasLocalStorage()) {
1615
24.0k
    QualType Ty = CGM.getContext().getBaseElementType(D.getType());
1616
24.0k
    if (Ty->isRecordType())
1617
6.99k
      if (const CXXConstructExpr *E =
1618
5.99k
          dyn_cast_or_null<CXXConstructExpr>(D.getInit())) {
1619
5.99k
        const CXXConstructorDecl *CD = E->getConstructor();
1620
5.99k
        if (CD->isTrivial() && 
CD->isDefaultConstructor()1.06k
)
1621
1.03k
          return CGM.EmitNullConstant(D.getType());
1622
22.9k
      }
1623
22.9k
    InConstantContext = true;
1624
22.9k
  }
1625
38.8k
1626
37.8k
  QualType destType = D.getType();
1627
37.8k
1628
  // Try to emit the initializer.  Note that this can allow some things that
1629
  // are not allowed by tryEmitPrivateForMemory alone.
1630
37.8k
  if (auto value = D.evaluateValue()) {
1631
13.1k
    return tryEmitPrivateForMemory(*value, destType);
1632
13.1k
  }
1633
24.7k
1634
  // FIXME: Implement C++11 [basic.start.init]p2: if the initializer of a
1635
  // reference is a constant expression, and the reference binds to a temporary,
1636
  // then constant initialization is performed. ConstExprEmitter will
1637
  // incorrectly emit a prvalue constant in this case, and the calling code
1638
  // interprets that as the (pointer) value of the reference, rather than the
1639
  // desired value of the referee.
1640
24.7k
  if (destType->isReferenceType())
1641
3.34k
    return nullptr;
1642
21.4k
1643
21.4k
  const Expr *E = D.getInit();
1644
21.4k
  assert(E && "No initializer to emit");
1645
21.4k
1646
21.4k
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1647
21.4k
  auto C =
1648
21.4k
    ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), nonMemoryDestType);
1649
19.1k
  return (C ? 
emitForMemory(C, destType)2.26k
: nullptr);
1650
21.4k
}
1651
1652
llvm::Constant *
1653
143
ConstantEmitter::tryEmitAbstractForMemory(const Expr *E, QualType destType) {
1654
143
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1655
143
  auto C = tryEmitAbstract(E, nonMemoryDestType);
1656
135
  return (C ? emitForMemory(C, destType) : 
nullptr8
);
1657
143
}
1658
1659
llvm::Constant *
1660
ConstantEmitter::tryEmitAbstractForMemory(const APValue &value,
1661
556
                                          QualType destType) {
1662
556
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1663
556
  auto C = tryEmitAbstract(value, nonMemoryDestType);
1664
556
  return (C ? emitForMemory(C, destType) : 
nullptr0
);
1665
556
}
1666
1667
llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const Expr *E,
1668
11.4k
                                                         QualType destType) {
1669
11.4k
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1670
11.4k
  llvm::Constant *C = tryEmitPrivate(E, nonMemoryDestType);
1671
10.9k
  return (C ? emitForMemory(C, destType) : 
nullptr471
);
1672
11.4k
}
1673
1674
llvm::Constant *ConstantEmitter::tryEmitPrivateForMemory(const APValue &value,
1675
28.0k
                                                         QualType destType) {
1676
28.0k
  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
1677
28.0k
  auto C = tryEmitPrivate(value, nonMemoryDestType);
1678
28.0k
  return (C ? emitForMemory(C, destType) : 
nullptr0
);
1679
28.0k
}
1680
1681
llvm::Constant *ConstantEmitter::emitForMemory(CodeGenModule &CGM,
1682
                                               llvm::Constant *C,
1683
42.1k
                                               QualType destType) {
1684
  // For an _Atomic-qualified constant, we may need to add tail padding.
1685
42.1k
  if (auto AT = destType->getAs<AtomicType>()) {
1686
95
    QualType destValueType = AT->getValueType();
1687
95
    C = emitForMemory(CGM, C, destValueType);
1688
95
1689
95
    uint64_t innerSize = CGM.getContext().getTypeSize(destValueType);
1690
95
    uint64_t outerSize = CGM.getContext().getTypeSize(destType);
1691
95
    if (innerSize == outerSize)
1692
94
      return C;
1693
1
1694
1
    assert(innerSize < outerSize && "emitted over-large constant for atomic");
1695
1
    llvm::Constant *elts[] = {
1696
1
      C,
1697
1
      llvm::ConstantAggregateZero::get(
1698
1
          llvm::ArrayType::get(CGM.Int8Ty, (outerSize - innerSize) / 8))
1699
1
    };
1700
1
    return llvm::ConstantStruct::getAnon(elts);
1701
1
  }
1702
42.0k
1703
  // Zero-extend bool.
1704
42.0k
  if (C->getType()->isIntegerTy(1)) {
1705
361
    llvm::Type *boolTy = CGM.getTypes().ConvertTypeForMem(destType);
1706
361
    return llvm::ConstantExpr::getZExt(C, boolTy);
1707
361
  }
1708
41.6k
1709
41.6k
  return C;
1710
41.6k
}
1711
1712
llvm::Constant *ConstantEmitter::tryEmitPrivate(const Expr *E,
1713
12.3k
                                                QualType destType) {
1714
12.3k
  Expr::EvalResult Result;
1715
12.3k
1716
12.3k
  bool Success = false;
1717
12.3k
1718
12.3k
  if (destType->isReferenceType())
1719
10
    Success = E->EvaluateAsLValue(Result, CGM.getContext());
1720
12.3k
  else
1721
12.3k
    Success = E->EvaluateAsRValue(Result, CGM.getContext(), InConstantContext);
1722
12.3k
1723
12.3k
  llvm::Constant *C;
1724
12.3k
  if (Success && 
!Result.HasSideEffects10.6k
)
1725
10.6k
    C = tryEmitPrivate(Result.Val, destType);
1726
1.71k
  else
1727
1.71k
    C = ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), destType);
1728
12.3k
1729
12.3k
  return C;
1730
12.3k
}
1731
1732
29.6k
llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) {
1733
29.6k
  return getTargetCodeGenInfo().getNullPointer(*this, T, QT);
1734
29.6k
}
1735
1736
namespace {
1737
/// A struct which can be used to peephole certain kinds of finalization
1738
/// that normally happen during l-value emission.
1739
struct ConstantLValue {
1740
  llvm::Constant *Value;
1741
  bool HasOffsetApplied;
1742
1743
  /*implicit*/ ConstantLValue(llvm::Constant *value,
1744
                              bool hasOffsetApplied = false)
1745
7.19k
    : Value(value), HasOffsetApplied(hasOffsetApplied) {}
1746
1747
  /*implicit*/ ConstantLValue(ConstantAddress address)
1748
3.95k
    : ConstantLValue(address.getPointer()) {}
1749
};
1750
1751
/// A helper class for emitting constant l-values.
1752
class ConstantLValueEmitter : public ConstStmtVisitor<ConstantLValueEmitter,
1753
                                                      ConstantLValue> {
1754
  CodeGenModule &CGM;
1755
  ConstantEmitter &Emitter;
1756
  const APValue &Value;
1757
  QualType DestType;
1758
1759
  // Befriend StmtVisitorBase so that we don't have to expose Visit*.
1760
  friend StmtVisitorBase;
1761
1762
public:
1763
  ConstantLValueEmitter(ConstantEmitter &emitter, const APValue &value,
1764
                        QualType destType)
1765
7.93k
    : CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType) {}
1766
1767
  llvm::Constant *tryEmit();
1768
1769
private:
1770
  llvm::Constant *tryEmitAbsolute(llvm::Type *destTy);
1771
  ConstantLValue tryEmitBase(const APValue::LValueBase &base);
1772
1773
0
  ConstantLValue VisitStmt(const Stmt *S) { return nullptr; }
1774
  ConstantLValue VisitConstantExpr(const ConstantExpr *E);
1775
  ConstantLValue VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
1776
  ConstantLValue VisitStringLiteral(const StringLiteral *E);
1777
  ConstantLValue VisitObjCBoxedExpr(const ObjCBoxedExpr *E);
1778
  ConstantLValue VisitObjCEncodeExpr(const ObjCEncodeExpr *E);
1779
  ConstantLValue VisitObjCStringLiteral(const ObjCStringLiteral *E);
1780
  ConstantLValue VisitPredefinedExpr(const PredefinedExpr *E);
1781
  ConstantLValue VisitAddrLabelExpr(const AddrLabelExpr *E);
1782
  ConstantLValue VisitCallExpr(const CallExpr *E);
1783
  ConstantLValue VisitBlockExpr(const BlockExpr *E);
1784
  ConstantLValue VisitCXXTypeidExpr(const CXXTypeidExpr *E);
1785
  ConstantLValue VisitMaterializeTemporaryExpr(
1786
                                         const MaterializeTemporaryExpr *E);
1787
1788
7.19k
  bool hasNonZeroOffset() const {
1789
7.19k
    return !Value.getLValueOffset().isZero();
1790
7.19k
  }
1791
1792
  /// Return the value offset.
1793
268
  llvm::Constant *getOffset() {
1794
268
    return llvm::ConstantInt::get(CGM.Int64Ty,
1795
268
                                  Value.getLValueOffset().getQuantity());
1796
268
  }
1797
1798
  /// Apply the value offset to the given constant.
1799
7.19k
  llvm::Constant *applyOffset(llvm::Constant *C) {
1800
7.19k
    if (!hasNonZeroOffset())
1801
7.14k
      return C;
1802
50
1803
50
    llvm::Type *origPtrTy = C->getType();
1804
50
    unsigned AS = origPtrTy->getPointerAddressSpace();
1805
50
    llvm::Type *charPtrTy = CGM.Int8Ty->getPointerTo(AS);
1806
50
    C = llvm::ConstantExpr::getBitCast(C, charPtrTy);
1807
50
    C = llvm::ConstantExpr::getGetElementPtr(CGM.Int8Ty, C, getOffset());
1808
50
    C = llvm::ConstantExpr::getPointerCast(C, origPtrTy);
1809
50
    return C;
1810
50
  }
1811
};
1812
1813
}
1814
1815
7.93k
llvm::Constant *ConstantLValueEmitter::tryEmit() {
1816
7.93k
  const APValue::LValueBase &base = Value.getLValueBase();
1817
7.93k
1818
  // The destination type should be a pointer or reference
1819
  // type, but it might also be a cast thereof.
1820
  //
1821
  // FIXME: the chain of casts required should be reflected in the APValue.
1822
  // We need this in order to correctly handle things like a ptrtoint of a
1823
  // non-zero null pointer and addrspace casts that aren't trivially
1824
  // represented in LLVM IR.
1825
7.93k
  auto destTy = CGM.getTypes().ConvertTypeForMem(DestType);
1826
7.93k
  assert(isa<llvm::IntegerType>(destTy) || isa<llvm::PointerType>(destTy));
1827
7.93k
1828
  // If there's no base at all, this is a null or absolute pointer,
1829
  // possibly cast back to an integer type.
1830
7.93k
  if (!base) {
1831
731
    return tryEmitAbsolute(destTy);
1832
731
  }
1833
7.19k
1834
  // Otherwise, try to emit the base.
1835
7.19k
  ConstantLValue result = tryEmitBase(base);
1836
7.19k
1837
  // If that failed, we're done.
1838
7.19k
  llvm::Constant *value = result.Value;
1839
7.19k
  if (!value) 
return nullptr0
;
1840
7.19k
1841
  // Apply the offset if necessary and not already done.
1842
7.19k
  if (!result.HasOffsetApplied) {
1843
7.19k
    value = applyOffset(value);
1844
7.19k
  }
1845
7.19k
1846
  // Convert to the appropriate type; this could be an lvalue for
1847
  // an integer.  FIXME: performAddrSpaceCast
1848
7.19k
  if (isa<llvm::PointerType>(destTy))
1849
7.18k
    return llvm::ConstantExpr::getPointerCast(value, destTy);
1850
19
1851
19
  return llvm::ConstantExpr::getPtrToInt(value, destTy);
1852
19
}
1853
1854
/// Try to emit an absolute l-value, such as a null pointer or an integer
1855
/// bitcast to pointer type.
1856
llvm::Constant *
1857
731
ConstantLValueEmitter::tryEmitAbsolute(llvm::Type *destTy) {
1858
  // If we're producing a pointer, this is easy.
1859
731
  auto destPtrTy = cast<llvm::PointerType>(destTy);
1860
731
  if (Value.isNullPointer()) {
1861
    // FIXME: integer offsets from non-zero null pointers.
1862
513
    return CGM.getNullPointer(destPtrTy, DestType);
1863
513
  }
1864
218
1865
  // Convert the integer to a pointer-sized integer before converting it
1866
  // to a pointer.
1867
  // FIXME: signedness depends on the original integer type.
1868
218
  auto intptrTy = CGM.getDataLayout().getIntPtrType(destPtrTy);
1869
218
  llvm::Constant *C;
1870
218
  C = llvm::ConstantExpr::getIntegerCast(getOffset(), intptrTy,
1871
218
                                         /*isSigned*/ false);
1872
218
  C = llvm::ConstantExpr::getIntToPtr(C, destPtrTy);
1873
218
  return C;
1874
218
}
1875
1876
ConstantLValue
1877
7.19k
ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) {
1878
  // Handle values.
1879
7.19k
  if (const ValueDecl *D = base.dyn_cast<const ValueDecl*>()) {
1880
3.01k
    if (D->hasAttr<WeakRefAttr>())
1881
5
      return CGM.GetWeakRefReference(D).getPointer();
1882
3.01k
1883
3.01k
    if (auto FD = dyn_cast<FunctionDecl>(D))
1884
2.22k
      return CGM.GetAddrOfFunction(FD);
1885
792
1886
792
    if (auto VD = dyn_cast<VarDecl>(D)) {
1887
      // We can never refer to a variable with local storage.
1888
756
      if (!VD->hasLocalStorage()) {
1889
756
        if (VD->isFileVarDecl() || 
VD->hasExternalStorage()16
)
1890
741
          return CGM.GetAddrOfGlobalVar(VD);
1891
15
1892
15
        if (VD->isLocalVarDecl()) {
1893
15
          return CGM.getOrCreateStaticVarDecl(
1894
15
              *VD, CGM.getLLVMLinkageVarDefinition(VD, /*IsConstant=*/false));
1895
15
        }
1896
36
      }
1897
756
    }
1898
36
1899
36
    if (auto *GD = dyn_cast<MSGuidDecl>(D))
1900
36
      return CGM.GetAddrOfMSGuidDecl(GD);
1901
0
1902
0
    return nullptr;
1903
0
  }
1904
4.18k
1905
  // Handle typeid(T).
1906
4.18k
  if (TypeInfoLValue TI = base.dyn_cast<TypeInfoLValue>()) {
1907
142
    llvm::Type *StdTypeInfoPtrTy =
1908
142
        CGM.getTypes().ConvertType(base.getTypeInfoType())->getPointerTo();
1909
142
    llvm::Constant *TypeInfo =
1910
142
        CGM.GetAddrOfRTTIDescriptor(QualType(TI.getType(), 0));
1911
142
    if (TypeInfo->getType() != StdTypeInfoPtrTy)
1912
142
      TypeInfo = llvm::ConstantExpr::getBitCast(TypeInfo, StdTypeInfoPtrTy);
1913
142
    return TypeInfo;
1914
142
  }
1915
4.03k
1916
  // Otherwise, it must be an expression.
1917
4.03k
  return Visit(base.get<const Expr*>());
1918
4.03k
}
1919
1920
ConstantLValue
1921
0
ConstantLValueEmitter::VisitConstantExpr(const ConstantExpr *E) {
1922
0
  if (llvm::Constant *Result = Emitter.tryEmitConstantExpr(E))
1923
0
    return Result;
1924
0
  return Visit(E->getSubExpr());
1925
0
}
1926
1927
ConstantLValue
1928
14
ConstantLValueEmitter::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
1929
14
  return tryEmitGlobalCompoundLiteral(CGM, Emitter.CGF, E);
1930
14
}
1931
1932
ConstantLValue
1933
3.08k
ConstantLValueEmitter::VisitStringLiteral(const StringLiteral *E) {
1934
3.08k
  return CGM.GetAddrOfConstantStringFromLiteral(E);
1935
3.08k
}
1936
1937
ConstantLValue
1938
9
ConstantLValueEmitter::VisitObjCEncodeExpr(const ObjCEncodeExpr *E) {
1939
9
  return CGM.GetAddrOfConstantStringFromObjCEncode(E);
1940
9
}
1941
1942
static ConstantLValue emitConstantObjCStringLiteral(const StringLiteral *S,
1943
                                                    QualType T,
1944
316
                                                    CodeGenModule &CGM) {
1945
316
  auto C = CGM.getObjCRuntime().GenerateConstantString(S);
1946
316
  return C.getElementBitCast(CGM.getTypes().ConvertTypeForMem(T));
1947
316
}
1948
1949
ConstantLValue
1950
313
ConstantLValueEmitter::VisitObjCStringLiteral(const ObjCStringLiteral *E) {
1951
313
  return emitConstantObjCStringLiteral(E->getString(), E->getType(), CGM);
1952
313
}
1953
1954
ConstantLValue
1955
3
ConstantLValueEmitter::VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
1956
3
  assert(E->isExpressibleAsConstantInitializer() &&
1957
3
         "this boxed expression can't be emitted as a compile-time constant");
1958
3
  auto *SL = cast<StringLiteral>(E->getSubExpr()->IgnoreParenCasts());
1959
3
  return emitConstantObjCStringLiteral(SL, E->getType(), CGM);
1960
3
}
1961
1962
ConstantLValue
1963
3
ConstantLValueEmitter::VisitPredefinedExpr(const PredefinedExpr *E) {
1964
3
  return CGM.GetAddrOfConstantStringFromLiteral(E->getFunctionName());
1965
3
}
1966
1967
ConstantLValue
1968
36
ConstantLValueEmitter::VisitAddrLabelExpr(const AddrLabelExpr *E) {
1969
36
  assert(Emitter.CGF && "Invalid address of label expression outside function");
1970
36
  llvm::Constant *Ptr = Emitter.CGF->GetAddrOfLabel(E->getLabel());
1971
36
  Ptr = llvm::ConstantExpr::getBitCast(Ptr,
1972
36
                                   CGM.getTypes().ConvertType(E->getType()));
1973
36
  return Ptr;
1974
36
}
1975
1976
ConstantLValue
1977
365
ConstantLValueEmitter::VisitCallExpr(const CallExpr *E) {
1978
365
  unsigned builtin = E->getBuiltinCallee();
1979
365
  if (builtin != Builtin::BI__builtin___CFStringMakeConstantString &&
1980
0
      builtin != Builtin::BI__builtin___NSStringMakeConstantString)
1981
0
    return nullptr;
1982
365
1983
365
  auto literal = cast<StringLiteral>(E->getArg(0)->IgnoreParenCasts());
1984
365
  if (builtin == Builtin::BI__builtin___NSStringMakeConstantString) {
1985
0
    return CGM.getObjCRuntime().GenerateConstantString(literal);
1986
365
  } else {
1987
    // FIXME: need to deal with UCN conversion issues.
1988
365
    return CGM.GetAddrOfConstantCFString(literal);
1989
365
  }
1990
365
}
1991
1992
ConstantLValue
1993
80
ConstantLValueEmitter::VisitBlockExpr(const BlockExpr *E) {
1994
80
  StringRef functionName;
1995
80
  if (auto CGF = Emitter.CGF)
1996
38
    functionName = CGF->CurFn->getName();
1997
42
  else
1998
42
    functionName = "global";
1999
80
2000
80
  return CGM.GetAddrOfGlobalBlock(E, functionName);
2001
80
}
2002
2003
ConstantLValue
2004
0
ConstantLValueEmitter::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
2005
0
  QualType T;
2006
0
  if (E->isTypeOperand())
2007
0
    T = E->getTypeOperand(CGM.getContext());
2008
0
  else
2009
0
    T = E->getExprOperand()->getType();
2010
0
  return CGM.GetAddrOfRTTIDescriptor(T);
2011
0
}
2012
2013
ConstantLValue
2014
ConstantLValueEmitter::VisitMaterializeTemporaryExpr(
2015
130
                                            const MaterializeTemporaryExpr *E) {
2016
130
  assert(E->getStorageDuration() == SD_Static);
2017
130
  SmallVector<const Expr *, 2> CommaLHSs;
2018
130
  SmallVector<SubobjectAdjustment, 2> Adjustments;
2019
130
  const Expr *Inner =
2020
130
      E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
2021
130
  return CGM.GetAddrOfGlobalTemporary(E, Inner);
2022
130
}
2023
2024
llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
2025
47.5k
                                                QualType DestType) {
2026
47.5k
  switch (Value.getKind()) {
2027
0
  case APValue::None:
2028
0
  case APValue::Indeterminate:
2029
    // Out-of-lifetime and indeterminate values can be modeled as 'undef'.
2030
0
    return llvm::UndefValue::get(CGM.getTypes().ConvertType(DestType));
2031
7.93k
  case APValue::LValue:
2032
7.93k
    return ConstantLValueEmitter(*this, Value, DestType).tryEmit();
2033
28.7k
  case APValue::Int:
2034
28.7k
    return llvm::ConstantInt::get(CGM.getLLVMContext(), Value.getInt());
2035
328
  case APValue::FixedPoint:
2036
328
    return llvm::ConstantInt::get(CGM.getLLVMContext(),
2037
328
                                  Value.getFixedPoint().getValue());
2038
7
  case APValue::ComplexInt: {
2039
7
    llvm::Constant *Complex[2];
2040
7
2041
7
    Complex[0] = llvm::ConstantInt::get(CGM.getLLVMContext(),
2042
7
                                        Value.getComplexIntReal());
2043
7
    Complex[1] = llvm::ConstantInt::get(CGM.getLLVMContext(),
2044
7
                                        Value.getComplexIntImag());
2045
7
2046
    // FIXME: the target may want to specify that this is packed.
2047
7
    llvm::StructType *STy =
2048
7
        llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
2049
7
    return llvm::ConstantStruct::get(STy, Complex);
2050
0
  }
2051
2.68k
  case APValue::Float: {
2052
2.68k
    const llvm::APFloat &Init = Value.getFloat();
2053
2.68k
    if (&Init.getSemantics() == &llvm::APFloat::IEEEhalf() &&
2054
73
        !CGM.getContext().getLangOpts().NativeHalfType &&
2055
65
        CGM.getContext().getTargetInfo().useFP16ConversionIntrinsics())
2056
1
      return llvm::ConstantInt::get(CGM.getLLVMContext(),
2057
1
                                    Init.bitcastToAPInt());
2058
2.68k
    else
2059
2.68k
      return llvm::ConstantFP::get(CGM.getLLVMContext(), Init);
2060
0
  }
2061
37
  case APValue::ComplexFloat: {
2062
37
    llvm::Constant *Complex[2];
2063
37
2064
37
    Complex[0] = llvm::ConstantFP::get(CGM.getLLVMContext(),
2065
37
                                       Value.getComplexFloatReal());
2066
37
    Complex[1] = llvm::ConstantFP::get(CGM.getLLVMContext(),
2067
37
                                       Value.getComplexFloatImag());
2068
37
2069
    // FIXME: the target may want to specify that this is packed.
2070
37
    llvm::StructType *STy =
2071
37
        llvm::StructType::get(Complex[0]->getType(), Complex[1]->getType());
2072
37
    return llvm::ConstantStruct::get(STy, Complex);
2073
0
  }
2074
1.28k
  case APValue::Vector: {
2075
1.28k
    unsigned NumElts = Value.getVectorLength();
2076
1.28k
    SmallVector<llvm::Constant *, 4> Inits(NumElts);
2077
1.28k
2078
9.41k
    for (unsigned I = 0; I != NumElts; 
++I8.12k
) {
2079
8.12k
      const APValue &Elt = Value.getVectorElt(I);
2080
8.12k
      if (Elt.isInt())
2081
7.06k
        Inits[I] = llvm::ConstantInt::get(CGM.getLLVMContext(), Elt.getInt());
2082
1.06k
      else if (Elt.isFloat())
2083
1.06k
        Inits[I] = llvm::ConstantFP::get(CGM.getLLVMContext(), Elt.getFloat());
2084
1.06k
      else
2085
0
        llvm_unreachable("unsupported vector element type");
2086
8.12k
    }
2087
1.28k
    return llvm::ConstantVector::get(Inits);
2088
1.28k
  }
2089
5
  case APValue::AddrLabelDiff: {
2090
5
    const AddrLabelExpr *LHSExpr = Value.getAddrLabelDiffLHS();
2091
5
    const AddrLabelExpr *RHSExpr = Value.getAddrLabelDiffRHS();
2092
5
    llvm::Constant *LHS = tryEmitPrivate(LHSExpr, LHSExpr->getType());
2093
5
    llvm::Constant *RHS = tryEmitPrivate(RHSExpr, RHSExpr->getType());
2094
5
    if (!LHS || !RHS) 
return nullptr0
;
2095
5
2096
    // Compute difference
2097
5
    llvm::Type *ResultType = CGM.getTypes().ConvertType(DestType);
2098
5
    LHS = llvm::ConstantExpr::getPtrToInt(LHS, CGM.IntPtrTy);
2099
5
    RHS = llvm::ConstantExpr::getPtrToInt(RHS, CGM.IntPtrTy);
2100
5
    llvm::Constant *AddrLabelDiff = llvm::ConstantExpr::getSub(LHS, RHS);
2101
5
2102
    // LLVM is a bit sensitive about the exact format of the
2103
    // address-of-label difference; make sure to truncate after
2104
    // the subtraction.
2105
5
    return llvm::ConstantExpr::getTruncOrBitCast(AddrLabelDiff, ResultType);
2106
5
  }
2107
3.29k
  case APValue::Struct:
2108
3.29k
  case APValue::Union:
2109
3.29k
    return ConstStructBuilder::BuildStruct(*this, Value, DestType);
2110
2.92k
  case APValue::Array: {
2111
2.92k
    const ConstantArrayType *CAT =
2112
2.92k
        CGM.getContext().getAsConstantArrayType(DestType);
2113
2.92k
    unsigned NumElements = Value.getArraySize();
2114
2.92k
    unsigned NumInitElts = Value.getArrayInitializedElts();
2115
2.92k
2116
    // Emit array filler, if there is one.
2117
2.92k
    llvm::Constant *Filler = nullptr;
2118
2.92k
    if (Value.hasArrayFiller()) {
2119
556
      Filler = tryEmitAbstractForMemory(Value.getArrayFiller(),
2120
556
                                        CAT->getElementType());
2121
556
      if (!Filler)
2122
0
        return nullptr;
2123
2.92k
    }
2124
2.92k
2125
    // Emit initializer elements.
2126
2.92k
    SmallVector<llvm::Constant*, 16> Elts;
2127
2.92k
    if (Filler && 
Filler->isNullValue()556
)
2128
551
      Elts.reserve(NumInitElts + 1);
2129
2.37k
    else
2130
2.37k
      Elts.reserve(NumElements);
2131
2.92k
2132
2.92k
    llvm::Type *CommonElementType = nullptr;
2133
12.1k
    for (unsigned I = 0; I < NumInitElts; 
++I9.25k
) {
2134
9.25k
      llvm::Constant *C = tryEmitPrivateForMemory(
2135
9.25k
          Value.getArrayInitializedElt(I), CAT->getElementType());
2136
9.25k
      if (!C) 
return nullptr0
;
2137
9.25k
2138
9.25k
      if (I == 0)
2139
2.69k
        CommonElementType = C->getType();
2140
6.55k
      else if (C->getType() != CommonElementType)
2141
7
        CommonElementType = nullptr;
2142
9.25k
      Elts.push_back(C);
2143
9.25k
    }
2144
2.92k
2145
    // This means that the array type is probably "IncompleteType" or some
2146
    // type that is not ConstantArray.
2147
2.92k
    if (CAT == nullptr && 
CommonElementType == nullptr19
&&
!NumInitElts19
) {
2148
19
      const ArrayType *AT = CGM.getContext().getAsArrayType(DestType);
2149
19
      CommonElementType = CGM.getTypes().ConvertType(AT->getElementType());
2150
19
      llvm::ArrayType *AType = llvm::ArrayType::get(CommonElementType,
2151
19
                                                    NumElements);
2152
19
      return llvm::ConstantAggregateZero::get(AType);
2153
19
    }
2154
2.90k
2155
2.90k
    llvm::ArrayType *Desired =
2156
2.90k
        cast<llvm::ArrayType>(CGM.getTypes().ConvertType(DestType));
2157
2.90k
    return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
2158
2.90k
                             Filler);
2159
2.90k
  }
2160
263
  case APValue::MemberPointer:
2161
263
    return CGM.getCXXABI().EmitMemberPointer(Value, DestType);
2162
0
  }
2163
0
  llvm_unreachable("Unknown APValue kind");
2164
0
}
2165
2166
llvm::GlobalVariable *CodeGenModule::getAddrOfConstantCompoundLiteralIfEmitted(
2167
17
    const CompoundLiteralExpr *E) {
2168
17
  return EmittedCompoundLiterals.lookup(E);
2169
17
}
2170
2171
void CodeGenModule::setAddrOfConstantCompoundLiteral(
2172
15
    const CompoundLiteralExpr *CLE, llvm::GlobalVariable *GV) {
2173
15
  bool Ok = EmittedCompoundLiterals.insert(std::make_pair(CLE, GV)).second;
2174
15
  (void)Ok;
2175
15
  assert(Ok && "CLE has already been emitted!");
2176
15
}
2177
2178
ConstantAddress
2179
3
CodeGenModule::GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr *E) {
2180
3
  assert(E->isFileScope() && "not a file-scope compound literal expr");
2181
3
  return tryEmitGlobalCompoundLiteral(*this, nullptr, E);
2182
3
}
2183
2184
llvm::Constant *
2185
606
CodeGenModule::getMemberPointerConstant(const UnaryOperator *uo) {
2186
  // Member pointer constants always have a very particular form.
2187
606
  const MemberPointerType *type = cast<MemberPointerType>(uo->getType());
2188
606
  const ValueDecl *decl = cast<DeclRefExpr>(uo->getSubExpr())->getDecl();
2189
606
2190
  // A member function pointer.
2191
606
  if (const CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(decl))
2192
553
    return getCXXABI().EmitMemberFunctionPointer(method);
2193
53
2194
  // Otherwise, a member data pointer.
2195
53
  uint64_t fieldOffset = getContext().getFieldOffset(decl);
2196
53
  CharUnits chars = getContext().toCharUnitsFromBits((int64_t) fieldOffset);
2197
53
  return getCXXABI().EmitMemberDataPointer(type, chars);
2198
53
}
2199
2200
static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
2201
                                               llvm::Type *baseType,
2202
                                               const CXXRecordDecl *base);
2203
2204
static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
2205
                                        const RecordDecl *record,
2206
69
                                        bool asCompleteObject) {
2207
69
  const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record);
2208
69
  llvm::StructType *structure =
2209
42
    (asCompleteObject ? layout.getLLVMType()
2210
27
                      : layout.getBaseSubobjectLLVMType());
2211
69
2212
69
  unsigned numElements = structure->getNumElements();
2213
69
  std::vector<llvm::Constant *> elements(numElements);
2214
69
2215
69
  auto CXXR = dyn_cast<CXXRecordDecl>(record);
2216
  // Fill in all the bases.
2217
69
  if (CXXR) {
2218
25
    for (const auto &I : CXXR->bases()) {
2219
25
      if (I.isVirtual()) {
2220
        // Ignore virtual bases; if we're laying out for a complete
2221
        // object, we'll lay these out later.
2222
17
        continue;
2223
17
      }
2224
8
2225
8
      const CXXRecordDecl *base =
2226
8
        cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
2227
8
2228
      // Ignore empty bases.
2229
8
      if (base->isEmpty() ||
2230
8
          CGM.getContext().getASTRecordLayout(base).getNonVirtualSize()
2231
8
              .isZero())
2232
1
        continue;
2233
7
2234
7
      unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
2235
7
      llvm::Type *baseType = structure->getElementType(fieldIndex);
2236
7
      elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
2237
7
    }
2238
53
  }
2239
69
2240
  // Fill in all the fields.
2241
139
  for (const auto *Field : record->fields()) {
2242
    // Fill in non-bitfields. (Bitfields always use a zero pattern, which we
2243
    // will fill in later.)
2244
139
    if (!Field->isBitField() && 
!Field->isZeroSize(CGM.getContext())137
) {
2245
137
      unsigned fieldIndex = layout.getLLVMFieldNo(Field);
2246
137
      elements[fieldIndex] = CGM.EmitNullConstant(Field->getType());
2247
137
    }
2248
139
2249
    // For unions, stop after the first named field.
2250
139
    if (record->isUnion()) {
2251
4
      if (Field->getIdentifier())
2252
3
        break;
2253
1
      if (const auto *FieldRD = Field->getType()->getAsRecordDecl())
2254
1
        if (FieldRD->findFirstNamedDataMember())
2255
1
          break;
2256
1
    }
2257
139
  }
2258
69
2259
  // Fill in the virtual bases, if we're working with the complete object.
2260
69
  if (CXXR && 
asCompleteObject53
) {
2261
5
    for (const auto &I : CXXR->vbases()) {
2262
5
      const CXXRecordDecl *base =
2263
5
        cast<CXXRecordDecl>(I.getType()->castAs<RecordType>()->getDecl());
2264
5
2265
      // Ignore empty bases.
2266
5
      if (base->isEmpty())
2267
0
        continue;
2268
5
2269
5
      unsigned fieldIndex = layout.getVirtualBaseIndex(base);
2270
5
2271
      // We might have already laid this field out.
2272
5
      if (elements[fieldIndex]) 
continue0
;
2273
5
2274
5
      llvm::Type *baseType = structure->getElementType(fieldIndex);
2275
5
      elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
2276
5
    }
2277
26
  }
2278
69
2279
  // Now go through all other fields and zero them out.
2280
247
  for (unsigned i = 0; i != numElements; 
++i178
) {
2281
178
    if (!elements[i])
2282
29
      elements[i] = llvm::Constant::getNullValue(structure->getElementType(i));
2283
178
  }
2284
69
2285
69
  return llvm::ConstantStruct::get(structure, elements);
2286
69
}
2287
2288
/// Emit the null constant for a base subobject.
2289
static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
2290
                                               llvm::Type *baseType,
2291
12
                                               const CXXRecordDecl *base) {
2292
12
  const CGRecordLayout &baseLayout = CGM.getTypes().getCGRecordLayout(base);
2293
12
2294
  // Just zero out bases that don't have any pointer to data members.
2295
12
  if (baseLayout.isZeroInitializableAsBase())
2296
4
    return llvm::Constant::getNullValue(baseType);
2297
8
2298
  // Otherwise, we can just use its null constant.
2299
8
  return EmitNullConstant(CGM, base, /*asCompleteObject=*/false);
2300
8
}
2301
2302
llvm::Constant *ConstantEmitter::emitNullForMemory(CodeGenModule &CGM,
2303
57
                                                   QualType T) {
2304
57
  return emitForMemory(CGM, CGM.EmitNullConstant(T), T);
2305
57
}
2306
2307
32.1k
llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
2308
32.1k
  if (T->getAs<PointerType>())
2309
7.69k
    return getNullPointer(
2310
7.69k
        cast<llvm::PointerType>(getTypes().ConvertTypeForMem(T)), T);
2311
24.4k
2312
24.4k
  if (getTypes().isZeroInitializable(T))
2313
24.3k
    return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
2314
142
2315
142
  if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(T)) {
2316
11
    llvm::ArrayType *ATy =
2317
11
      cast<llvm::ArrayType>(getTypes().ConvertTypeForMem(T));
2318
11
2319
11
    QualType ElementTy = CAT->getElementType();
2320
11
2321
11
    llvm::Constant *Element =
2322
11
      ConstantEmitter::emitNullForMemory(*this, ElementTy);
2323
11
    unsigned NumElements = CAT->getSize().getZExtValue();
2324
11
    SmallVector<llvm::Constant *, 8> Array(NumElements, Element);
2325
11
    return llvm::ConstantArray::get(ATy, Array);
2326
11
  }
2327
131
2328
131
  if (const RecordType *RT = T->getAs<RecordType>())
2329
42
    return ::EmitNullConstant(*this, RT->getDecl(), /*complete object*/ true);
2330
89
2331
89
  assert(T->isMemberDataPointerType() &&
2332
89
         "Should only see pointers to data members here!");
2333
89
2334
89
  return getCXXABI().EmitNullMemberPointer(T->castAs<MemberPointerType>());
2335
89
}
2336
2337
llvm::Constant *
2338
19
CodeGenModule::EmitNullConstantForBase(const CXXRecordDecl *Record) {
2339
19
  return ::EmitNullConstant(*this, Record, false);
2340
19
}