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GenHeap.cpp
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//===--- GenHeap.cpp - Layout of heap objects and their metadata ----------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements routines for arbitrary Swift-native heap objects,
// such as layout and reference-counting.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/ErrorHandling.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Intrinsics.h"
#include "swift/Basic/Fallthrough.h"
#include "swift/Basic/SourceLoc.h"
#include "swift/ABI/MetadataValues.h"
#include "swift/AST/IRGenOptions.h"
#include "Explosion.h"
#include "GenProto.h"
#include "GenType.h"
#include "IRGenDebugInfo.h"
#include "IRGenFunction.h"
#include "IRGenModule.h"
#include "HeapTypeInfo.h"
#include "IndirectTypeInfo.h"
#include "WeakTypeInfo.h"
#include "GenHeap.h"
using namespace swift;
using namespace irgen;
/// Produce a constant to place in a metatype's isa field
/// corresponding to the given metadata kind.
static llvm::ConstantInt *getMetadataKind(IRGenModule &IGM,
MetadataKind kind) {
return llvm::ConstantInt::get(IGM.MetadataKindTy, uint8_t(kind));
}
/// Perform the layout required for a heap object.
HeapLayout::HeapLayout(IRGenModule &IGM, LayoutStrategy strategy,
ArrayRef<SILType> fieldTypes,
ArrayRef<const TypeInfo *> fieldTypeInfos,
llvm::StructType *typeToFill,
NecessaryBindings &&bindings)
: StructLayout(IGM, CanType(), LayoutKind::HeapObject, strategy,
fieldTypeInfos, typeToFill),
ElementTypes(fieldTypes.begin(), fieldTypes.end()),
Bindings(std::move(bindings))
{
#ifndef NDEBUG
assert(fieldTypeInfos.size() == fieldTypes.size()
&& "type infos don't match types");
if (!Bindings.empty()) {
assert(fieldTypeInfos.size() >= 1 && "no field for bindings");
auto fixedBindingsField = dyn_cast<FixedTypeInfo>(fieldTypeInfos[0]);
assert(fixedBindingsField
&& "bindings field is not fixed size");
assert(fixedBindingsField->getFixedSize()
== Bindings.getBufferSize(IGM)
&& fixedBindingsField->getFixedAlignment()
== IGM.getPointerAlignment()
&& "bindings field doesn't fit bindings");
}
#endif
}
HeapNonFixedOffsets::HeapNonFixedOffsets(IRGenFunction &IGF,
const HeapLayout &layout) {
if (!layout.isFixedLayout()) {
// Calculate all the non-fixed layouts.
// TODO: We could be lazier about this.
llvm::Value *offset = nullptr;
llvm::Value *totalAlign = llvm::ConstantInt::get(IGF.IGM.SizeTy,
layout.getAlignment().getMaskValue());
for (unsigned i : indices(layout.getElements())) {
auto &elt = layout.getElement(i);
auto eltTy = layout.getElementTypes()[i];
switch (elt.getKind()) {
case ElementLayout::Kind::InitialNonFixedSize:
// Factor the non-fixed-size field's alignment into the total alignment.
totalAlign = IGF.Builder.CreateOr(totalAlign,
elt.getType().getAlignmentMask(IGF, eltTy));
SWIFT_FALLTHROUGH;
case ElementLayout::Kind::Empty:
case ElementLayout::Kind::Fixed:
// Don't need to dynamically calculate this offset.
Offsets.push_back(nullptr);
break;
case ElementLayout::Kind::NonFixed:
// Start calculating non-fixed offsets from the end of the first fixed
// field.
assert(i > 0 && "shouldn't begin with a non-fixed field");
auto &prevElt = layout.getElement(i-1);
auto prevType = layout.getElementTypes()[i-1];
// Start calculating offsets from the last fixed-offset field.
if (!offset) {
Size lastFixedOffset = layout.getElement(i-1).getByteOffset();
if (auto *fixedType = dyn_cast<FixedTypeInfo>(&prevElt.getType())) {
// If the last fixed-offset field is also fixed-size, we can
// statically compute the end of the fixed-offset fields.
auto fixedEnd = lastFixedOffset + fixedType->getFixedSize();
offset
= llvm::ConstantInt::get(IGF.IGM.SizeTy, fixedEnd.getValue());
} else {
// Otherwise, we need to add the dynamic size to the fixed start
// offset.
offset
= llvm::ConstantInt::get(IGF.IGM.SizeTy,
lastFixedOffset.getValue());
offset = IGF.Builder.CreateAdd(offset,
prevElt.getType().getSize(IGF, prevType));
}
}
// Round up to alignment to get the offset.
auto alignMask = elt.getType().getAlignmentMask(IGF, eltTy);
auto notAlignMask = IGF.Builder.CreateNot(alignMask);
offset = IGF.Builder.CreateAdd(offset, alignMask);
offset = IGF.Builder.CreateAnd(offset, notAlignMask);
Offsets.push_back(offset);
// Advance by the field's size to start the next field.
offset = IGF.Builder.CreateAdd(offset,
elt.getType().getSize(IGF, eltTy));
totalAlign = IGF.Builder.CreateOr(totalAlign, alignMask);
break;
}
}
TotalSize = offset;
TotalAlignMask = totalAlign;
} else {
TotalSize = layout.emitSize(IGF.IGM);
TotalAlignMask = layout.emitAlignMask(IGF.IGM);
}
}
void irgen::emitDeallocateHeapObject(IRGenFunction &IGF,
llvm::Value *object,
llvm::Value *size,
llvm::Value *alignMask) {
// FIXME: We should call a fast deallocator for heap objects with
// known size.
IGF.Builder.CreateCall(IGF.IGM.getDeallocObjectFn(),
{object, size, alignMask});
}
void irgen::emitDeallocateClassInstance(IRGenFunction &IGF,
llvm::Value *object,
llvm::Value *size,
llvm::Value *alignMask) {
// FIXME: We should call a fast deallocator for heap objects with
// known size.
IGF.Builder.CreateCall(IGF.IGM.getDeallocClassInstanceFn(),
{object, size, alignMask});
}
void irgen::emitDeallocatePartialClassInstance(IRGenFunction &IGF,
llvm::Value *object,
llvm::Value *metadata,
llvm::Value *size,
llvm::Value *alignMask) {
// FIXME: We should call a fast deallocator for heap objects with
// known size.
IGF.Builder.CreateCall(IGF.IGM.getDeallocPartialClassInstanceFn(),
{object, metadata, size, alignMask});
}
/// Create the destructor function for a layout.
/// TODO: give this some reasonable name and possibly linkage.
static llvm::Function *createDtorFn(IRGenModule &IGM,
const HeapLayout &layout) {
llvm::Function *fn =
llvm::Function::Create(IGM.DeallocatingDtorTy,
llvm::Function::PrivateLinkage,
"objectdestroy", &IGM.Module);
fn->setAttributes(IGM.constructInitialAttributes());
IRGenFunction IGF(IGM, fn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, fn);
Address structAddr = layout.emitCastTo(IGF, &*fn->arg_begin());
// Bind necessary bindings, if we have them.
if (layout.hasBindings()) {
// The type metadata bindings should be at a fixed offset, so we can pass
// None for NonFixedOffsets. If we didn't, we'd have a chicken-egg problem.
auto bindingsAddr = layout.getElement(0).project(IGF, structAddr, None);
layout.getBindings().restore(IGF, bindingsAddr);
}
// Figure out the non-fixed offsets.
HeapNonFixedOffsets offsets(IGF, layout);
// Destroy the fields.
for (unsigned i : indices(layout.getElements())) {
auto &field = layout.getElement(i);
auto fieldTy = layout.getElementTypes()[i];
if (field.isPOD())
continue;
field.getType().destroy(IGF, field.project(IGF, structAddr, offsets),
fieldTy);
}
emitDeallocateHeapObject(IGF, &*fn->arg_begin(), offsets.getSize(),
offsets.getAlignMask());
IGF.Builder.CreateRetVoid();
return fn;
}
/// Create the size function for a layout.
/// TODO: give this some reasonable name and possibly linkage.
llvm::Constant *HeapLayout::createSizeFn(IRGenModule &IGM) const {
llvm::Function *fn =
llvm::Function::Create(IGM.DeallocatingDtorTy,
llvm::Function::PrivateLinkage,
"objectsize", &IGM.Module);
fn->setAttributes(IGM.constructInitialAttributes());
IRGenFunction IGF(IGM, fn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, fn);
// Ignore the object pointer; we aren't a dynamically-sized array,
// so it's pointless.
llvm::Value *size = emitSize(IGM);
IGF.Builder.CreateRet(size);
return fn;
}
static llvm::Constant *buildPrivateMetadata(IRGenModule &IGM,
const HeapLayout &layout,
llvm::Constant *dtorFn,
MetadataKind kind) {
// Build the fields of the private metadata.
SmallVector<llvm::Constant*, 4> fields;
fields.push_back(dtorFn);
fields.push_back(llvm::ConstantPointerNull::get(IGM.WitnessTablePtrTy));
fields.push_back(llvm::ConstantStruct::get(IGM.TypeMetadataStructTy,
getMetadataKind(IGM, kind)));
// Figure out the offset to the first element, which is necessary to be able
// to polymorphically project as a generic box.
auto elements = layout.getElements();
Size offset;
if (!elements.empty()
&& elements[0].getKind() == ElementLayout::Kind::Fixed)
offset = elements[0].getByteOffset();
else
offset = Size(0);
fields.push_back(llvm::ConstantInt::get(IGM.Int32Ty, offset.getValue()));
llvm::Constant *init =
llvm::ConstantStruct::get(IGM.FullBoxMetadataStructTy, fields);
llvm::GlobalVariable *var =
new llvm::GlobalVariable(IGM.Module, IGM.FullBoxMetadataStructTy,
/*constant*/ true,
llvm::GlobalVariable::PrivateLinkage, init,
"metadata");
llvm::Constant *indices[] = {
llvm::ConstantInt::get(IGM.Int32Ty, 0),
llvm::ConstantInt::get(IGM.Int32Ty, 2)
};
return llvm::ConstantExpr::getInBoundsGetElementPtr(
/*Ty=*/nullptr, var, indices);
}
llvm::Constant *HeapLayout::getPrivateMetadata(IRGenModule &IGM) const {
if (!privateMetadata)
privateMetadata = buildPrivateMetadata(IGM, *this, createDtorFn(IGM, *this),
MetadataKind::HeapLocalVariable);
return privateMetadata;
}
llvm::Value *IRGenFunction::emitUnmanagedAlloc(const HeapLayout &layout,
const llvm::Twine &name,
const HeapNonFixedOffsets *offsets) {
llvm::Value *metadata = layout.getPrivateMetadata(IGM);
llvm::Value *size, *alignMask;
if (offsets) {
size = offsets->getSize();
alignMask = offsets->getAlignMask();
} else {
size = layout.emitSize(IGM);
alignMask = layout.emitAlignMask(IGM);
}
return emitAllocObjectCall(metadata, size, alignMask, name);
}
namespace {
class BuiltinNativeObjectTypeInfo
: public HeapTypeInfo<BuiltinNativeObjectTypeInfo> {
public:
BuiltinNativeObjectTypeInfo(llvm::PointerType *storage,
Size size, SpareBitVector spareBits,
Alignment align)
: HeapTypeInfo(storage, size, spareBits, align) {}
/// Builtin.NativeObject uses Swift native reference-counting.
ReferenceCounting getReferenceCounting() const {
return ReferenceCounting::Native;
}
};
}
const LoadableTypeInfo *TypeConverter::convertBuiltinNativeObject() {
return new BuiltinNativeObjectTypeInfo(IGM.RefCountedPtrTy,
IGM.getPointerSize(),
IGM.getHeapObjectSpareBits(),
IGM.getPointerAlignment());
}
namespace {
/// A type implementation for an @unowned(unsafe) reference to an
/// object.
class UnmanagedReferenceTypeInfo
: public PODSingleScalarTypeInfo<UnmanagedReferenceTypeInfo,
LoadableTypeInfo> {
public:
UnmanagedReferenceTypeInfo(llvm::Type *type,
const SpareBitVector &spareBits,
Size size, Alignment alignment)
: PODSingleScalarTypeInfo(type, size, spareBits, alignment) {}
// Unmanaged types have the same spare bits as managed heap objects.
bool mayHaveExtraInhabitants(IRGenModule &IGM) const override {
return true;
}
unsigned getFixedExtraInhabitantCount(IRGenModule &IGM) const override {
return getHeapObjectExtraInhabitantCount(IGM);
}
APInt getFixedExtraInhabitantValue(IRGenModule &IGM,
unsigned bits,
unsigned index) const override {
return getHeapObjectFixedExtraInhabitantValue(IGM, bits, index, 0);
}
llvm::Value *getExtraInhabitantIndex(IRGenFunction &IGF, Address src,
SILType T)
const override {
return getHeapObjectExtraInhabitantIndex(IGF, src);
}
void storeExtraInhabitant(IRGenFunction &IGF, llvm::Value *index,
Address dest, SILType T) const override {
return storeHeapObjectExtraInhabitant(IGF, index, dest);
}
};
}
const LoadableTypeInfo *
TypeConverter::createUnmanagedStorageType(llvm::Type *valueType) {
return new UnmanagedReferenceTypeInfo(valueType,
IGM.getHeapObjectSpareBits(),
IGM.getPointerSize(),
IGM.getPointerAlignment());
}
namespace {
/// A type implementation for an [unowned] reference to an object
/// with a known-Swift reference count.
class NativeUnownedReferenceTypeInfo
: public SingleScalarTypeInfo<NativeUnownedReferenceTypeInfo,
LoadableTypeInfo> {
llvm::Type *ValueType;
public:
NativeUnownedReferenceTypeInfo(llvm::Type *valueType,
llvm::Type *unownedType,
SpareBitVector &&spareBits,
Size size, Alignment alignment)
: SingleScalarTypeInfo(unownedType, size, std::move(spareBits),
alignment, IsNotPOD, IsFixedSize),
ValueType(valueType) {}
enum { IsScalarPOD = false };
llvm::Type *getScalarType() const {
return ValueType;
}
Address projectScalar(IRGenFunction &IGF, Address addr) const {
return IGF.Builder.CreateBitCast(addr, ValueType->getPointerTo());
}
void emitScalarRetain(IRGenFunction &IGF, llvm::Value *value) const {
IGF.emitNativeUnownedRetain(value);
}
void emitScalarRelease(IRGenFunction &IGF, llvm::Value *value) const {
IGF.emitNativeUnownedRelease(value);
}
void emitScalarFixLifetime(IRGenFunction &IGF, llvm::Value *value) const {
IGF.emitFixLifetime(value);
}
unsigned getFixedExtraInhabitantCount(IRGenModule &IGM) const override {
return IGM.getUnownedExtraInhabitantCount(ReferenceCounting::Native);
}
APInt getFixedExtraInhabitantValue(IRGenModule &IGM,
unsigned bits,
unsigned index) const override {
return IGM.getUnownedExtraInhabitantValue(bits, index,
ReferenceCounting::Native);
}
llvm::Value *getExtraInhabitantIndex(IRGenFunction &IGF, Address src,
SILType T) const override {
return IGF.getUnownedExtraInhabitantIndex(src,
ReferenceCounting::Native);
}
void storeExtraInhabitant(IRGenFunction &IGF, llvm::Value *index,
Address dest, SILType T) const override {
return IGF.storeUnownedExtraInhabitant(index, dest,
ReferenceCounting::Native);
}
APInt getFixedExtraInhabitantMask(IRGenModule &IGM) const override {
return IGM.getUnownedExtraInhabitantMask(ReferenceCounting::Native);
}
};
/// A type implementation for a [weak] reference to an object
/// with a known-Swift reference count.
class NativeWeakReferenceTypeInfo
: public IndirectTypeInfo<NativeWeakReferenceTypeInfo,
WeakTypeInfo> {
llvm::Type *ValueType;
public:
NativeWeakReferenceTypeInfo(llvm::Type *valueType,
llvm::Type *weakType,
Size size, Alignment alignment,
SpareBitVector &&spareBits)
: IndirectTypeInfo(weakType, size, alignment, std::move(spareBits)),
ValueType(valueType) {}
void initializeWithCopy(IRGenFunction &IGF, Address destAddr,
Address srcAddr, SILType T) const override {
IGF.emitNativeWeakCopyInit(destAddr, srcAddr);
}
void initializeWithTake(IRGenFunction &IGF, Address destAddr,
Address srcAddr, SILType T) const override {
IGF.emitNativeWeakTakeInit(destAddr, srcAddr);
}
void assignWithCopy(IRGenFunction &IGF, Address destAddr,
Address srcAddr, SILType T) const override {
IGF.emitNativeWeakCopyAssign(destAddr, srcAddr);
}
void assignWithTake(IRGenFunction &IGF, Address destAddr,
Address srcAddr, SILType T) const override {
IGF.emitNativeWeakTakeAssign(destAddr, srcAddr);
}
void destroy(IRGenFunction &IGF, Address addr, SILType T) const override {
IGF.emitNativeWeakDestroy(addr);
}
llvm::Type *getOptionalIntType() const {
return llvm::IntegerType::get(ValueType->getContext(),
getFixedSize().getValueInBits());
}
void weakLoadStrong(IRGenFunction &IGF, Address addr,
Explosion &out) const override {
auto value = IGF.emitNativeWeakLoadStrong(addr, ValueType);
// The optional will be lowered to an integer type the size of the word.
out.add(IGF.Builder.CreatePtrToInt(value, getOptionalIntType()));
}
void weakTakeStrong(IRGenFunction &IGF, Address addr,
Explosion &out) const override {
auto value = IGF.emitNativeWeakTakeStrong(addr, ValueType);
// The optional will be lowered to an integer type the size of the word.
out.add(IGF.Builder.CreatePtrToInt(value, getOptionalIntType()));
}
void weakInit(IRGenFunction &IGF, Explosion &in,
Address dest) const override {
llvm::Value *value = in.claimNext();
// The optional will be lowered to an integer type the size of the word.
assert(value->getType() == getOptionalIntType());
value = IGF.Builder.CreateIntToPtr(value, ValueType);
IGF.emitNativeWeakInit(value, dest);
}
void weakAssign(IRGenFunction &IGF, Explosion &in,
Address dest) const override {
llvm::Value *value = in.claimNext();
// The optional will be lowered to an integer type the size of the word.
assert(value->getType() == getOptionalIntType());
value = IGF.Builder.CreateIntToPtr(value, ValueType);
IGF.emitNativeWeakAssign(value, dest);
}
};
}
SpareBitVector IRGenModule::getWeakReferenceSpareBits() const {
// The runtime needs to be able to freely manipulate live weak
// references without worrying about us mucking around with their
// bits, so weak references are completely opaque.
return SpareBitVector::getConstant(getWeakReferenceSize().getValueInBits(),
false);
}
SpareBitVector
IRGenModule::getUnownedReferenceSpareBits(ReferenceCounting style) const {
// If unknown references don't exist, we can just use the same rules as
// regular pointers.
if (!ObjCInterop) {
assert(style == ReferenceCounting::Native);
return getHeapObjectSpareBits();
}
// Otherwise, we have to be conservative (even with native
// reference-counting) in order to interoperate with code that might
// be working more generically with the memory/type.
return SpareBitVector::getConstant(getPointerSize().getValueInBits(), false);
}
unsigned IRGenModule::getUnownedExtraInhabitantCount(ReferenceCounting style) {
if (!ObjCInterop) {
assert(style == ReferenceCounting::Native);
return getHeapObjectExtraInhabitantCount(*this);
}
return 1;
}
APInt IRGenModule::getUnownedExtraInhabitantValue(unsigned bits, unsigned index,
ReferenceCounting style) {
if (!ObjCInterop) {
assert(style == ReferenceCounting::Native);
return getHeapObjectFixedExtraInhabitantValue(*this, bits, index, 0);
}
assert(index == 0);
return APInt(bits, 0);
}
APInt IRGenModule::getUnownedExtraInhabitantMask(ReferenceCounting style) {
return APInt::getAllOnesValue(getPointerSize().getValueInBits());
}
llvm::Value *IRGenFunction::getUnownedExtraInhabitantIndex(Address src,
ReferenceCounting style) {
if (!IGM.ObjCInterop) {
assert(style == ReferenceCounting::Native);
return getHeapObjectExtraInhabitantIndex(*this, src);
}
assert(src.getAddress()->getType() == IGM.UnownedReferencePtrTy);
src = Builder.CreateStructGEP(src, 0, Size(0));
llvm::Value *ptr = Builder.CreateLoad(src);
llvm::Value *isNull = Builder.CreateIsNull(ptr);
llvm::Value *result =
Builder.CreateSelect(isNull, Builder.getInt32(0),
llvm::ConstantInt::getSigned(IGM.Int32Ty, -1));
return result;
}
void IRGenFunction::storeUnownedExtraInhabitant(llvm::Value *index,
Address dest,
ReferenceCounting style) {
if (!IGM.ObjCInterop) {
assert(style == ReferenceCounting::Native);
return storeHeapObjectExtraInhabitant(*this, index, dest);
}
// Since there's only one legal extra inhabitant, it has to have
// the null pattern.
assert(dest.getAddress()->getType() == IGM.UnownedReferencePtrTy);
dest = Builder.CreateStructGEP(dest, 0, Size(0));
llvm::Value *null = llvm::ConstantPointerNull::get(IGM.RefCountedPtrTy);
Builder.CreateStore(null, dest);
}
namespace {
/// A type implementation for an [unowned] reference to an object
/// that is not necessarily a Swift object.
class UnknownUnownedReferenceTypeInfo :
public IndirectTypeInfo<UnknownUnownedReferenceTypeInfo, FixedTypeInfo> {
public:
UnknownUnownedReferenceTypeInfo(llvm::Type *unownedType,
SpareBitVector &&spareBits,
Size size, Alignment alignment)
: IndirectTypeInfo(unownedType, size, std::move(spareBits), alignment,
IsNotPOD, IsNotBitwiseTakable, IsFixedSize) {
}
void assignWithCopy(IRGenFunction &IGF, Address dest,
Address src, SILType type) const override {
IGF.emitUnknownUnownedCopyAssign(dest, src);
}
void initializeWithCopy(IRGenFunction &IGF, Address dest,
Address src, SILType type) const override {
IGF.emitUnknownUnownedCopyInit(dest, src);
}
void assignWithTake(IRGenFunction &IGF, Address dest,
Address src, SILType type) const override {
IGF.emitUnknownUnownedTakeAssign(dest, src);
}
void initializeWithTake(IRGenFunction &IGF, Address dest,
Address src, SILType type) const override {
IGF.emitUnknownUnownedTakeInit(dest, src);
}
void destroy(IRGenFunction &IGF, Address addr,
SILType type) const override {
IGF.emitUnknownUnownedDestroy(addr);
}
// Unowned types have the same extra inhabitants as normal pointers.
// They do not, however, necessarily have any spare bits.
unsigned getFixedExtraInhabitantCount(IRGenModule &IGM) const override {
return IGM.getUnownedExtraInhabitantCount(ReferenceCounting::Unknown);
}
APInt getFixedExtraInhabitantValue(IRGenModule &IGM,
unsigned bits,
unsigned index) const override {
return IGM.getUnownedExtraInhabitantValue(bits, index,
ReferenceCounting::Unknown);
}
llvm::Value *getExtraInhabitantIndex(IRGenFunction &IGF, Address src,
SILType T) const override {
return IGF.getUnownedExtraInhabitantIndex(src,
ReferenceCounting::Unknown);
}
void storeExtraInhabitant(IRGenFunction &IGF, llvm::Value *index,
Address dest, SILType T) const override {
return IGF.storeUnownedExtraInhabitant(index, dest,
ReferenceCounting::Unknown);
}
APInt getFixedExtraInhabitantMask(IRGenModule &IGM) const override {
return IGM.getUnownedExtraInhabitantMask(ReferenceCounting::Unknown);
}
};
/// A type implementation for a [weak] reference to an object
/// that is not necessarily a Swift object.
class UnknownWeakReferenceTypeInfo :
public IndirectTypeInfo<UnknownWeakReferenceTypeInfo,
WeakTypeInfo> {
/// We need to separately store the value type because we always
/// use the same type to store the weak reference struct.
llvm::Type *ValueType;
public:
UnknownWeakReferenceTypeInfo(llvm::Type *valueType,
llvm::Type *weakType,
Size size, Alignment alignment,
SpareBitVector &&spareBits)
: IndirectTypeInfo(weakType, size, alignment, std::move(spareBits)),
ValueType(valueType) {}
void initializeWithCopy(IRGenFunction &IGF, Address destAddr,
Address srcAddr, SILType T) const override {
IGF.emitUnknownWeakCopyInit(destAddr, srcAddr);
}
void initializeWithTake(IRGenFunction &IGF, Address destAddr,
Address srcAddr, SILType T) const override {
IGF.emitUnknownWeakTakeInit(destAddr, srcAddr);
}
void assignWithCopy(IRGenFunction &IGF, Address destAddr,
Address srcAddr, SILType T) const override {
IGF.emitUnknownWeakCopyAssign(destAddr, srcAddr);
}
void assignWithTake(IRGenFunction &IGF, Address destAddr,
Address srcAddr, SILType T) const override {
IGF.emitUnknownWeakTakeAssign(destAddr, srcAddr);
}
void destroy(IRGenFunction &IGF, Address addr, SILType T) const override {
IGF.emitUnknownWeakDestroy(addr);
}
llvm::Type *getOptionalIntType() const {
return llvm::IntegerType::get(ValueType->getContext(),
getFixedSize().getValueInBits());
}
void weakLoadStrong(IRGenFunction &IGF, Address addr,
Explosion &out) const override {
auto value = IGF.emitUnknownWeakLoadStrong(addr, ValueType);
// The optional will be lowered to an integer type the size of the word.
out.add(IGF.Builder.CreatePtrToInt(value, getOptionalIntType()));
}
void weakTakeStrong(IRGenFunction &IGF, Address addr,
Explosion &out) const override {
auto value = IGF.emitUnknownWeakTakeStrong(addr, ValueType);
// The optional will be lowered to an integer type the size of the word.
out.add(IGF.Builder.CreatePtrToInt(value, getOptionalIntType()));
}
void weakInit(IRGenFunction &IGF, Explosion &in,
Address dest) const override {
llvm::Value *value = in.claimNext();
// The optional will be lowered to an integer type the size of the word.
assert(value->getType() == getOptionalIntType());
value = IGF.Builder.CreateIntToPtr(value, ValueType);
IGF.emitUnknownWeakInit(value, dest);
}
void weakAssign(IRGenFunction &IGF, Explosion &in,
Address dest) const override {
llvm::Value *value = in.claimNext();
// The optional will be lowered to an integer type the size of the word.
assert(value->getType() == getOptionalIntType());
value = IGF.Builder.CreateIntToPtr(value, ValueType);
IGF.emitUnknownWeakAssign(value, dest);
}
};
}
const TypeInfo *TypeConverter::createUnownedStorageType(llvm::Type *valueType,
ReferenceCounting style) {
auto &&spareBits = IGM.getUnownedReferenceSpareBits(style);
switch (style) {
case ReferenceCounting::Native:
return new NativeUnownedReferenceTypeInfo(valueType,
IGM.UnownedReferencePtrTy->getElementType(),
std::move(spareBits),
IGM.getPointerSize(),
IGM.getPointerAlignment());
case ReferenceCounting::ObjC:
case ReferenceCounting::Block:
case ReferenceCounting::Unknown:
return new UnknownUnownedReferenceTypeInfo(
IGM.UnownedReferencePtrTy->getElementType(),
std::move(spareBits),
IGM.getPointerSize(),
IGM.getPointerAlignment());
case ReferenceCounting::Bridge:
case ReferenceCounting::Error:
llvm_unreachable("not supported!");
}
llvm_unreachable("bad reference-counting style");
}
const WeakTypeInfo *TypeConverter::createWeakStorageType(llvm::Type *valueType,
ReferenceCounting style) {
switch (style) {
case ReferenceCounting::Native:
return new NativeWeakReferenceTypeInfo(valueType,
IGM.WeakReferencePtrTy->getElementType(),
IGM.getWeakReferenceSize(),
IGM.getWeakReferenceAlignment(),
IGM.getWeakReferenceSpareBits());
case ReferenceCounting::ObjC:
case ReferenceCounting::Block:
case ReferenceCounting::Unknown:
return new UnknownWeakReferenceTypeInfo(valueType,
IGM.WeakReferencePtrTy->getElementType(),
IGM.getWeakReferenceSize(),
IGM.getWeakReferenceAlignment(),
IGM.getWeakReferenceSpareBits());
case ReferenceCounting::Bridge:
case ReferenceCounting::Error:
llvm_unreachable("not supported!");
}
llvm_unreachable("bad reference-counting style");
}
/// Does the given value superficially not require reference-counting?
static bool doesNotRequireRefCounting(llvm::Value *value) {
// Constants never require reference-counting.
return isa<llvm::ConstantPointerNull>(value);
}
static llvm::FunctionType *getTypeOfFunction(llvm::Constant *fn) {
return cast<llvm::FunctionType>(fn->getType()->getPointerElementType());
}
/// Emit a unary call to perform a ref-counting operation.
///
/// \param fn - expected signature 'void (T)'
static void emitUnaryRefCountCall(IRGenFunction &IGF,
llvm::Constant *fn,
llvm::Value *value) {
auto cc = IGF.IGM.DefaultCC;
if (auto fun = dyn_cast<llvm::Function>(fn))
cc = fun->getCallingConv();
// Instead of casting the input, we cast the function type.
// This tends to produce less IR, but might be evil.
if (value->getType() != getTypeOfFunction(fn)->getParamType(0)) {
llvm::FunctionType *fnType =
llvm::FunctionType::get(IGF.IGM.VoidTy, value->getType(), false);
fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
}
// Emit the call.
llvm::CallInst *call = IGF.Builder.CreateCall(fn, value);
call->setCallingConv(cc);
call->setDoesNotThrow();
}
/// Emit a copy-like call to perform a ref-counting operation.
///
/// \param fn - expected signature 'void (T, T)'
static void emitCopyLikeCall(IRGenFunction &IGF,
llvm::Constant *fn,
llvm::Value *dest,
llvm::Value *src) {
assert(dest->getType() == src->getType() &&
"type mismatch in binary refcounting operation");
auto cc = IGF.IGM.DefaultCC;
if (auto fun = dyn_cast<llvm::Function>(fn))
cc = fun->getCallingConv();
// Instead of casting the inputs, we cast the function type.
// This tends to produce less IR, but might be evil.
if (dest->getType() != getTypeOfFunction(fn)->getParamType(0)) {
llvm::Type *paramTypes[] = { dest->getType(), dest->getType() };
llvm::FunctionType *fnType =
llvm::FunctionType::get(IGF.IGM.VoidTy, paramTypes, false);
fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
}
// Emit the call.
llvm::CallInst *call = IGF.Builder.CreateCall(fn, {dest, src});
call->setCallingConv(cc);
call->setDoesNotThrow();
}
/// Emit a call to a function with a loadWeak-like signature.
///
/// \param fn - expected signature 'T (Weak*)'
static llvm::Value *emitLoadWeakLikeCall(IRGenFunction &IGF,
llvm::Constant *fn,
llvm::Value *addr,
llvm::Type *resultType) {
assert((addr->getType() == IGF.IGM.WeakReferencePtrTy ||
addr->getType() == IGF.IGM.UnownedReferencePtrTy) &&
"address is not of a weak or unowned reference");
auto cc = IGF.IGM.DefaultCC;
if (auto fun = dyn_cast<llvm::Function>(fn))
cc = fun->getCallingConv();
// Instead of casting the output, we cast the function type.
// This tends to produce less IR, but might be evil.
if (resultType != getTypeOfFunction(fn)->getReturnType()) {
llvm::Type *paramTypes[] = { addr->getType() };
llvm::FunctionType *fnType =
llvm::FunctionType::get(resultType, paramTypes, false);
fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
}
// Emit the call.
llvm::CallInst *call = IGF.Builder.CreateCall(fn, addr);
call->setCallingConv(cc);
call->setDoesNotThrow();
return call;
}
/// Emit a call to a function with a storeWeak-like signature.
///
/// \param fn - expected signature 'void (Weak*, T)'
static void emitStoreWeakLikeCall(IRGenFunction &IGF,
llvm::Constant *fn,
llvm::Value *addr,
llvm::Value *value) {
assert((addr->getType() == IGF.IGM.WeakReferencePtrTy ||
addr->getType() == IGF.IGM.UnownedReferencePtrTy) &&
"address is not of a weak or unowned reference");
auto cc = IGF.IGM.DefaultCC;
if (auto fun = dyn_cast<llvm::Function>(fn))
cc = fun->getCallingConv();
// Instead of casting the inputs, we cast the function type.
// This tends to produce less IR, but might be evil.
if (value->getType() != getTypeOfFunction(fn)->getParamType(1)) {
llvm::Type *paramTypes[] = { addr->getType(), value->getType() };
llvm::FunctionType *fnType =
llvm::FunctionType::get(IGF.IGM.VoidTy, paramTypes, false);
fn = llvm::ConstantExpr::getBitCast(fn, fnType->getPointerTo());
}
// Emit the call.
llvm::CallInst *call = IGF.Builder.CreateCall(fn, {addr, value});
call->setCallingConv(cc);
call->setDoesNotThrow();
}
/// Emit a call to swift_retain.
void IRGenFunction::emitNativeStrongRetain(llvm::Value *value) {
if (doesNotRequireRefCounting(value))
return;
// Make sure the input pointer is the right type.
if (value->getType() != IGM.RefCountedPtrTy)
value = Builder.CreateBitCast(value, IGM.RefCountedPtrTy);
// Emit the call.
llvm::CallInst *call =
Builder.CreateCall(IGM.getNativeStrongRetainFn(), value);
call->setDoesNotThrow();
}
/// Emit a store of a live value to the given retaining variable.
void IRGenFunction::emitNativeStrongAssign(llvm::Value *newValue,
Address address) {
// Pull the old value out of the address.
llvm::Value *oldValue = Builder.CreateLoad(address);
// We assume the new value is already retained.
Builder.CreateStore(newValue, address);
// Release the old value.
emitNativeStrongRelease(oldValue);
}
/// Emit an initialize of a live value to the given retaining variable.
void IRGenFunction::emitNativeStrongInit(llvm::Value *newValue,
Address address) {
// We assume the new value is already retained.
Builder.CreateStore(newValue, address);
}
/// Emit a release of a live value with the given refcounting implementation.
void IRGenFunction::emitStrongRelease(llvm::Value *value,
ReferenceCounting refcounting) {
switch (refcounting) {
case ReferenceCounting::Native:
return emitNativeStrongRelease(value);
case ReferenceCounting::ObjC:
return emitObjCStrongRelease(value);
case ReferenceCounting::Block:
return emitBlockRelease(value);
case ReferenceCounting::Unknown:
return emitUnknownStrongRelease(value);
case ReferenceCounting::Bridge:
return emitBridgeStrongRelease(value);
case ReferenceCounting::Error:
return emitErrorStrongRelease(value);
}
}
void IRGenFunction::emitStrongRetain(llvm::Value *value,
ReferenceCounting refcounting) {
switch (refcounting) {
case ReferenceCounting::Native:
emitNativeStrongRetain(value);
return;
case ReferenceCounting::Bridge:
emitBridgeStrongRetain(value);
return;
case ReferenceCounting::ObjC:
emitObjCStrongRetain(value);
return;
case ReferenceCounting::Block:
emitBlockCopyCall(value);
return;
case ReferenceCounting::Unknown:
emitUnknownStrongRetain(value);