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swift-mirror/lib/IRGen/GenClass.cpp
Joe Groff 9c5564f808 Allow subclasses of specific instantiations of ObjC generic classes. 
If a subclass grounds all the type parameters from its base class, we don't have to worry about any erasure edge cases. We should be able to support this, giving existing code that subclasses the nongeneric form of the class a migration path. Spot-fix some places in IRGen where we assume we can't emit static references to ObjC generic classes or metaclasses.
2016-04-06 21:19:11 -07:00

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//===--- GenClass.cpp - Swift IR Generation For 'class' Types -------------===//
//
// 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 IR generation for class types.
//
//===----------------------------------------------------------------------===//
#include "GenClass.h"
#include "swift/ABI/Class.h"
#include "swift/ABI/MetadataValues.h"
#include "swift/AST/AttrKind.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/Decl.h"
#include "swift/AST/IRGenOptions.h"
#include "swift/AST/Module.h"
#include "swift/AST/Pattern.h"
#include "swift/AST/PrettyStackTrace.h"
#include "swift/AST/TypeMemberVisitor.h"
#include "swift/AST/Types.h"
#include "swift/SIL/SILModule.h"
#include "swift/SIL/SILType.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/IR/CallSite.h"
#include "Explosion.h"
#include "GenFunc.h"
#include "GenMeta.h"
#include "GenObjC.h"
#include "GenProto.h"
#include "GenType.h"
#include "IRGenDebugInfo.h"
#include "IRGenFunction.h"
#include "IRGenModule.h"
#include "GenHeap.h"
#include "HeapTypeInfo.h"
using namespace swift;
using namespace irgen;
static ClassDecl *getRootClass(ClassDecl *theClass) {
while (theClass->hasSuperclass()) {
theClass = theClass->getSuperclass()->getClassOrBoundGenericClass();
assert(theClass && "base type of class not a class?");
}
return theClass;
}
/// What reference counting mechanism does a class have?
ReferenceCounting irgen::getReferenceCountingForClass(IRGenModule &IGM,
ClassDecl *theClass) {
// If ObjC interop is disabled, we have a Swift refcount.
if (!IGM.ObjCInterop)
return ReferenceCounting::Native;
// NOTE: if you change this, change Type::usesNativeReferenceCounting.
// If the root class is implemented in swift, then we have a swift
// refcount; otherwise, we have an ObjC refcount.
if (hasKnownSwiftImplementation(IGM, getRootClass(theClass)))
return ReferenceCounting::Native;
return ReferenceCounting::ObjC;
}
/// What isa encoding mechanism does a type have?
IsaEncoding irgen::getIsaEncodingForType(IRGenModule &IGM,
CanType type) {
if (auto theClass = type->getClassOrBoundGenericClass()) {
// We can access the isas of pure Swift classes directly.
if (hasKnownSwiftImplementation(IGM, getRootClass(theClass)))
return IsaEncoding::Pointer;
// For ObjC or mixed classes, we need to use object_getClass.
return IsaEncoding::ObjC;
}
// Non-class heap objects should be pure Swift, so we can access their isas
// directly.
return IsaEncoding::Pointer;
}
namespace {
/// Layout information for class types.
class ClassTypeInfo : public HeapTypeInfo<ClassTypeInfo> {
ClassDecl *TheClass;
mutable StructLayout *Layout;
mutable ClassLayout FieldLayout;
/// Can we use swift reference-counting, or do we have to use
/// objc_retain/release?
const ReferenceCounting Refcount;
void generateLayout(IRGenModule &IGM) const;
public:
ClassTypeInfo(llvm::PointerType *irType, Size size,
SpareBitVector spareBits, Alignment align,
ClassDecl *D, ReferenceCounting refcount)
: HeapTypeInfo(irType, size, std::move(spareBits), align), TheClass(D),
Layout(nullptr), Refcount(refcount) {}
ReferenceCounting getReferenceCounting() const {
return Refcount;
}
~ClassTypeInfo() {
delete Layout;
}
ClassDecl *getClass() const { return TheClass; }
const StructLayout &getLayout(IRGenModule &IGM) const;
const struct ClassLayout &getClassLayout(IRGenModule &IGM) const;
Alignment getHeapAlignment(IRGenModule &IGM) const {
return getLayout(IGM).getAlignment();
}
ArrayRef<ElementLayout> getElements(IRGenModule &IGM) const {
return getLayout(IGM).getElements();
}
};
} // end anonymous namespace.
/// Return the lowered type for the class's 'self' type within its context.
static SILType getSelfType(ClassDecl *base) {
auto loweredTy = base->getDeclaredTypeInContext()->getCanonicalType();
return SILType::getPrimitiveObjectType(loweredTy);
}
/// Return the type info for the class's 'self' type within its context.
static const ClassTypeInfo &getSelfTypeInfo(IRGenModule &IGM, ClassDecl *base) {
return IGM.getTypeInfo(getSelfType(base)).as<ClassTypeInfo>();
}
namespace {
class ClassLayoutBuilder : public StructLayoutBuilder {
SmallVector<ElementLayout, 8> Elements;
SmallVector<VarDecl*, 8> AllStoredProperties;
SmallVector<FieldAccess, 8> AllFieldAccesses;
// The manner in which this class embeds the field offset vector of
// the superclass.
//
// - ConstantDirect - size and content of superclass metadata is known
// at compile time.
// - NonConstantDirect - size of superclass metadata is known, however
// some field offsets depend on the sizes of resilient types, or the
// size of an imported Objective-C base class.
// - ConstantIndirect - size of superclass metadata is known, however
// some field offsets depend on generic parameters, sizes of
// resilient types, or the size of an imported Objective-C base class.
// - NonConstantIndirect - size of superclass metadata is unknown,
// so all class metadata entries for members of this class must be
// accessed indirectly.
FieldAccess MetadataAccess = FieldAccess::ConstantDirect;
unsigned NumInherited = 0;
// Does the class metadata require dynamic initialization above and
// beyond what the runtime can automatically achieve?
//
// This is true if the class or any of its ancestors:
// - is generic,
// - is resilient,
// - has a parent type which isn't emittable as a constant,
// - or has a field with resilient layout.
bool ClassMetadataRequiresDynamicInitialization = false;
// Does the superclass have a fixed number of stored properties?
// If not, and the class has generally-dependent layout, we have to
// access stored properties through an indirect offset into the field
// offset vector.
bool ClassHasFixedFieldCount = true;
// Does the class have a fixed size up until the current point?
// If not, we have to access stored properties either ivar offset globals,
// or through the field offset vector, based on whether the layout has
// dependent layout.
bool ClassHasFixedSize = true;
// Does the class have identical layout under all generic substitutions?
// If not, we can have to access stored properties through the field
// offset vector in the instantiated type metadata.
bool ClassHasConcreteLayout = true;
public:
ClassLayoutBuilder(IRGenModule &IGM, ClassDecl *theClass)
: StructLayoutBuilder(IGM)
{
// Start by adding a heap header.
addHeapHeader();
// Next, add the fields for the given class.
addFieldsForClass(theClass, getSelfType(theClass));
// Add these fields to the builder.
addFields(Elements, LayoutStrategy::Universal);
}
/// Return the element layouts.
ArrayRef<ElementLayout> getElements() const {
return Elements;
}
ClassLayout getClassLayout() const {
ClassLayout fieldLayout;
auto allStoredProps = IGM.Context.AllocateCopy(AllStoredProperties);
auto inheritedStoredProps = allStoredProps.slice(0, NumInherited);
fieldLayout.AllStoredProperties = allStoredProps;
fieldLayout.InheritedStoredProperties = inheritedStoredProps;
fieldLayout.AllFieldAccesses = IGM.Context.AllocateCopy(AllFieldAccesses);
fieldLayout.MetadataAccess = MetadataAccess;
fieldLayout.MetadataRequiresDynamicInitialization =
ClassMetadataRequiresDynamicInitialization;
return fieldLayout;
}
private:
void addFieldsForClass(ClassDecl *theClass,
SILType classType) {
if (theClass->isGenericContext())
ClassMetadataRequiresDynamicInitialization = true;
if (!ClassMetadataRequiresDynamicInitialization) {
if (auto parentType =
theClass->getDeclContext()->getDeclaredTypeInContext()) {
if (!tryEmitConstantTypeMetadataRef(IGM,
parentType->getCanonicalType(),
SymbolReferenceKind::Absolute))
ClassMetadataRequiresDynamicInitialization = true;
}
}
if (theClass->hasSuperclass()) {
// TODO: apply substitutions when computing base-class layouts!
SILType superclassType = classType.getSuperclass(nullptr);
auto superclass = superclassType.getClassOrBoundGenericClass();
assert(superclass);
if (superclass->hasClangNode()) {
// As a special case, assume NSObject has a fixed layout.
if (superclass->getName() !=
IGM.Context.getSwiftId(KnownFoundationEntity::NSObject)) {
// If the superclass was imported from Objective-C, its size is
// not known at compile time. However, since the field offset
// vector only stores offsets of stored properties defined in
// Swift, we don't have to worry about indirect indexing of
// the field offset vector.
ClassHasFixedSize = false;
}
} else if (IGM.isResilient(superclass, ResilienceExpansion::Maximal)) {
// If the superclass is resilient, the number of stored properties
// is not known at compile time.
ClassMetadataRequiresDynamicInitialization = true;
ClassHasFixedFieldCount = false;
ClassHasFixedSize = false;
// If the superclass is in a generic context, conservatively
// assume the layout depends on generic parameters, since we
// can't look at stored properties.
if (superclassType.hasArchetype())
ClassHasConcreteLayout = false;
} else {
// Otherwise, we have total knowledge of the class and its
// fields, so walk them to compute the layout.
addFieldsForClass(superclass, superclassType);
// Count the fields we got from the superclass.
NumInherited = Elements.size();
}
}
// The final value is field access for the superclass of the class we're
// building.
MetadataAccess = getCurFieldAccess();
// Collect fields from this class and add them to the layout as a chunk.
addDirectFieldsFromClass(theClass, classType);
}
void addDirectFieldsFromClass(ClassDecl *theClass,
SILType classType) {
for (VarDecl *var : theClass->getStoredProperties()) {
SILType type = classType.getFieldType(var, *IGM.SILMod);
auto &eltType = IGM.getTypeInfo(type);
if (!eltType.isFixedSize()) {
ClassMetadataRequiresDynamicInitialization = true;
ClassHasFixedSize = false;
if (type.hasArchetype())
ClassHasConcreteLayout = false;
}
Elements.push_back(ElementLayout::getIncomplete(eltType));
AllStoredProperties.push_back(var);
AllFieldAccesses.push_back(getCurFieldAccess());
}
}
FieldAccess getCurFieldAccess() const {
if (ClassHasConcreteLayout) {
if (ClassHasFixedSize) {
// No generic parameter dependencies, fixed size. The field offset
// is known at compile time.
return FieldAccess::ConstantDirect;
} else {
// No generic parameter dependencies, but some stored properties
// have unknown size. The field offset is stored in a global constant
// and set up by the Objective-C or Swift runtime, depending on the
// class's heritage.
return FieldAccess::NonConstantDirect;
}
} else {
if (ClassHasFixedFieldCount) {
// Layout depends on generic parameters, but the number of fields
// is known. The field offset is loaded from a fixed offset in the
// field offset vector in type metadata.
return FieldAccess::ConstantIndirect;
} else {
// Layout depends on generic parameters, and the number of fields
// is not known at compile time either. The field index is loaded
// from a global variable set up by the runtime, and then this
// index is used to load the offset from the field offset vector.
return FieldAccess::NonConstantIndirect;
}
}
}
};
}
void ClassTypeInfo::generateLayout(IRGenModule &IGM) const {
assert(!Layout && FieldLayout.AllStoredProperties.empty() &&
"already generated layout");
// Add the heap header.
ClassLayoutBuilder builder(IGM, getClass());
// Set the body of the class type.
auto classPtrTy = cast<llvm::PointerType>(getStorageType());
auto classTy = cast<llvm::StructType>(classPtrTy->getElementType());
builder.setAsBodyOfStruct(classTy);
// Record the layout.
Layout = new StructLayout(builder,
TheClass->getDeclaredTypeInContext()->getCanonicalType(),
classTy, builder.getElements());
FieldLayout = builder.getClassLayout();
}
const StructLayout &ClassTypeInfo::getLayout(IRGenModule &IGM) const {
// Return the cached layout if available.
if (Layout) return *Layout;
generateLayout(IGM);
return *Layout;
}
const ClassLayout &ClassTypeInfo::getClassLayout(IRGenModule &IGM) const {
// Return the cached layout if available.
if (Layout)
return FieldLayout;
generateLayout(IGM);
return FieldLayout;
}
/// Cast the base to i8*, apply the given inbounds offset (in bytes,
/// as a size_t), and cast to a pointer to the given type.
llvm::Value *IRGenFunction::emitByteOffsetGEP(llvm::Value *base,
llvm::Value *offset,
llvm::Type *objectType,
const llvm::Twine &name) {
assert(offset->getType() == IGM.SizeTy);
auto addr = Builder.CreateBitCast(base, IGM.Int8PtrTy);
addr = Builder.CreateInBoundsGEP(addr, offset);
return Builder.CreateBitCast(addr, objectType->getPointerTo(), name);
}
/// Cast the base to i8*, apply the given inbounds offset (in bytes,
/// as a size_t), and create an address in the given type.
Address IRGenFunction::emitByteOffsetGEP(llvm::Value *base,
llvm::Value *offset,
const TypeInfo &type,
const llvm::Twine &name) {
auto addr = emitByteOffsetGEP(base, offset, type.getStorageType(), name);
return type.getAddressForPointer(addr);
}
/// Emit a field l-value by applying the given offset to the given base.
static OwnedAddress emitAddressAtOffset(IRGenFunction &IGF,
SILType baseType,
llvm::Value *base,
llvm::Value *offset,
VarDecl *field) {
auto &fieldTI =
IGF.getTypeInfo(baseType.getFieldType(field, *IGF.IGM.SILMod));
auto addr = IGF.emitByteOffsetGEP(base, offset, fieldTI,
base->getName() + "." + field->getName().str());
return OwnedAddress(addr, base);
}
OwnedAddress irgen::projectPhysicalClassMemberAddress(IRGenFunction &IGF,
llvm::Value *base,
SILType baseType,
SILType fieldType,
VarDecl *field) {
// If the field is empty, its address doesn't matter.
auto &fieldTI = IGF.getTypeInfo(fieldType);
if (fieldTI.isKnownEmpty(ResilienceExpansion::Maximal)) {
return OwnedAddress(fieldTI.getUndefAddress(), base);
}
auto &baseClassTI = IGF.getTypeInfo(baseType).as<ClassTypeInfo>();
ClassDecl *baseClass = baseType.getClassOrBoundGenericClass();
// TODO: Lay out the class based on the substituted baseType rather than
// the generic type. Doing this requires that we also handle
// specialized layout in ClassTypeInfo.
auto &classLayout = baseClassTI.getClassLayout(IGF.IGM);
unsigned fieldIndex = classLayout.getFieldIndex(field);
switch (classLayout.AllFieldAccesses[fieldIndex]) {
case FieldAccess::ConstantDirect: {
Address baseAddr(base, baseClassTI.getHeapAlignment(IGF.IGM));
auto &element = baseClassTI.getElements(IGF.IGM)[fieldIndex];
Address memberAddr = element.project(IGF, baseAddr, None);
// We may need to bitcast the address if the field is of a generic type.
if (memberAddr.getType()->getElementType() != fieldTI.getStorageType())
memberAddr = IGF.Builder.CreateBitCast(memberAddr,
fieldTI.getStorageType()->getPointerTo());
return OwnedAddress(memberAddr, base);
}
case FieldAccess::NonConstantDirect: {
Address offsetA = IGF.IGM.getAddrOfFieldOffset(field, /*indirect*/ false,
NotForDefinition);
auto offsetVar = cast<llvm::GlobalVariable>(offsetA.getAddress());
offsetVar->setConstant(false);
auto offset = IGF.Builder.CreateLoad(offsetA, "offset");
return emitAddressAtOffset(IGF, baseType, base, offset, field);
}
case FieldAccess::ConstantIndirect: {
auto metadata = emitHeapMetadataRefForHeapObject(IGF, base, baseType);
auto offset = emitClassFieldOffset(IGF, baseClass, field, metadata);
return emitAddressAtOffset(IGF, baseType, base, offset, field);
}
case FieldAccess::NonConstantIndirect: {
auto metadata = emitHeapMetadataRefForHeapObject(IGF, base, baseType);
Address indirectOffsetA =
IGF.IGM.getAddrOfFieldOffset(field, /*indirect*/ true,
NotForDefinition);
auto offsetVar = cast<llvm::GlobalVariable>(indirectOffsetA.getAddress());
offsetVar->setConstant(false);
auto indirectOffset =
IGF.Builder.CreateLoad(indirectOffsetA, "indirect-offset");
auto offsetA =
IGF.emitByteOffsetGEP(metadata, indirectOffset, IGF.IGM.SizeTy);
auto offset =
IGF.Builder.CreateLoad(Address(offsetA, IGF.IGM.getPointerAlignment()));
return emitAddressAtOffset(IGF, baseType, base, offset, field);
}
}
llvm_unreachable("bad field-access strategy");
}
/// Emit an allocation of a class.
llvm::Value *irgen::emitClassAllocation(IRGenFunction &IGF, SILType selfType,
bool objc, int &StackAllocSize) {
auto &classTI = IGF.getTypeInfo(selfType).as<ClassTypeInfo>();
auto classType = selfType.getSwiftRValueType();
// If we need to use Objective-C allocation, do so.
// If the root class isn't known to use the Swift allocator, we need
// to call [self alloc].
if (objc) {
llvm::Value *metadata =
emitClassHeapMetadataRef(IGF, classType, MetadataValueType::ObjCClass,
/*allow uninitialized*/ true);
StackAllocSize = -1;
return emitObjCAllocObjectCall(IGF, metadata, selfType.getSwiftRValueType());
}
llvm::Value *metadata =
emitClassHeapMetadataRef(IGF, classType, MetadataValueType::TypeMetadata);
// FIXME: Long-term, we clearly need a specialized runtime entry point.
llvm::Value *size, *alignMask;
std::tie(size, alignMask)
= emitClassFragileInstanceSizeAndAlignMask(IGF,
selfType.getClassOrBoundGenericClass(),
metadata);
auto &layout = classTI.getLayout(IGF.IGM);
llvm::Type *destType = layout.getType()->getPointerTo();
llvm::Value *val = nullptr;
if (layout.isFixedLayout() &&
(int)layout.getSize().getValue() < StackAllocSize) {
// Allocate the object on the stack.
auto *Ty = layout.getType();
auto Alloca = IGF.createAlloca(Ty, layout.getAlignment(),
"reference.raw");
val = Alloca.getAddress();
assert(val->getType() == destType);
val = IGF.Builder.CreateBitCast(val, IGF.IGM.RefCountedPtrTy);
val = IGF.emitInitStackObjectCall(metadata, val, "reference.new");
StackAllocSize = layout.getSize().getValue();
} else {
// Allocate the object on the heap.
val = IGF.emitAllocObjectCall(metadata, size, alignMask, "reference.new");
StackAllocSize = -1;
}
return IGF.Builder.CreateBitCast(val, destType);
}
llvm::Value *irgen::emitClassAllocationDynamic(IRGenFunction &IGF,
llvm::Value *metadata,
SILType selfType,
bool objc) {
// If we need to use Objective-C allocation, do so.
if (objc) {
return emitObjCAllocObjectCall(IGF, metadata,
selfType.getSwiftRValueType());
}
// Otherwise, allocate using Swift's routines.
llvm::Value *size, *alignMask;
std::tie(size, alignMask)
= emitClassResilientInstanceSizeAndAlignMask(IGF,
selfType.getClassOrBoundGenericClass(),
metadata);
llvm::Value *val = IGF.emitAllocObjectCall(metadata, size, alignMask,
"reference.new");
auto &classTI = IGF.getTypeInfo(selfType).as<ClassTypeInfo>();
auto &layout = classTI.getLayout(IGF.IGM);
llvm::Type *destType = layout.getType()->getPointerTo();
return IGF.Builder.CreateBitCast(val, destType);
}
/// Look for the instance method:
/// func __getInstanceSizeAndAlignMask() -> (Int, Int)
/// and use it to populate 'size' and 'alignMask' if it's present.
static bool getInstanceSizeByMethod(IRGenFunction &IGF,
CanType selfType,
ClassDecl *selfClass,
llvm::Value *selfValue,
llvm::Value *&size,
llvm::Value *&alignMask) {
// Look for a single instance method with the magic name.
FuncDecl *fn; {
auto name = IGF.IGM.Context.getIdentifier("__getInstanceSizeAndAlignMask");
SmallVector<ValueDecl*, 4> results;
selfClass->lookupQualified(selfType, name, NL_KnownNonCascadingDependency,
nullptr, results);
if (results.size() != 1)
return false;
fn = dyn_cast<FuncDecl>(results[0]);
if (!fn)
return false;
}
// Check whether the SIL module defines it. (We need a type for it.)
SILDeclRef fnRef(fn, SILDeclRef::Kind::Func,
ResilienceExpansion::Minimal,
/*uncurryLevel*/ 1,
/*foreign*/ false);
SILFunction *silFn = IGF.IGM.SILMod->lookUpFunction(fnRef);
if (!silFn)
return false;
// Check that it returns two size_t's and takes no other arguments.
auto fnType = silFn->getLoweredFunctionType();
if (fnType->getParameters().size() != 1)
return false;
if (fnType->getNumDirectResults() != 2 ||
fnType->getNumIndirectResults() != 0)
return false;
auto results = fnType->getDirectResults();
if (results[0].getConvention() != ResultConvention::Unowned ||
results[1].getConvention() != ResultConvention::Unowned)
return false;
llvm::Function *llvmFn =
IGF.IGM.getAddrOfSILFunction(silFn, NotForDefinition);
auto llvmFnTy = llvmFn->getFunctionType();
if (llvmFnTy->getNumParams() != 1) return false;
auto returnType = dyn_cast<llvm::StructType>(llvmFnTy->getReturnType());
if (!returnType ||
returnType->getNumElements() != 2 ||
returnType->getElementType(0) != IGF.IGM.SizeTy ||
returnType->getElementType(1) != IGF.IGM.SizeTy)
return false;
// Retain 'self' if necessary.
if (fnType->getParameters()[0].isConsumed()) {
IGF.emitNativeStrongRetain(selfValue);
}
// Adjust down to the defining subclass type if necessary.
selfValue = IGF.Builder.CreateBitCast(selfValue, llvmFnTy->getParamType(0));
// Emit a direct call.
auto result = IGF.Builder.CreateCall(llvmFn, selfValue);
result->setCallingConv(llvmFn->getCallingConv());
// Extract the size and alignment.
size = IGF.Builder.CreateExtractValue(result, 0, "size");
alignMask = IGF.Builder.CreateExtractValue(result, 1, "alignMask");
return true;
}
/// Get the instance size and alignment mask for the given class
/// instance.
static void getInstanceSizeAndAlignMask(IRGenFunction &IGF,
SILType selfType,
ClassDecl *selfClass,
llvm::Value *selfValue,
llvm::Value *&size,
llvm::Value *&alignMask) {
// Use the magic __getInstanceSizeAndAlignMask method if we can
// see a declaration of it
if (getInstanceSizeByMethod(IGF, selfType.getSwiftRValueType(),
selfClass, selfValue, size, alignMask))
return;
// Try to determine the size of the object we're deallocating.
auto &info = IGF.IGM.getTypeInfo(selfType).as<ClassTypeInfo>();
auto &layout = info.getLayout(IGF.IGM);
// If it's fixed, emit the constant size and alignment mask.
if (layout.isFixedLayout()) {
size = layout.emitSize(IGF.IGM);
alignMask = layout.emitAlignMask(IGF.IGM);
return;
}
// Otherwise, get them from the metadata.
llvm::Value *metadata =
emitHeapMetadataRefForHeapObject(IGF, selfValue, selfType);
std::tie(size, alignMask)
= emitClassFragileInstanceSizeAndAlignMask(IGF, selfClass, metadata);
}
void irgen::emitClassDeallocation(IRGenFunction &IGF, SILType selfType,
llvm::Value *selfValue) {
auto *theClass = selfType.getClassOrBoundGenericClass();
llvm::Value *size, *alignMask;
getInstanceSizeAndAlignMask(IGF, selfType, theClass, selfValue,
size, alignMask);
selfValue = IGF.Builder.CreateBitCast(selfValue, IGF.IGM.RefCountedPtrTy);
emitDeallocateClassInstance(IGF, selfValue, size, alignMask);
}
void irgen::emitPartialClassDeallocation(IRGenFunction &IGF,
SILType selfType,
llvm::Value *selfValue,
llvm::Value *metadataValue) {
auto *theClass = selfType.getClassOrBoundGenericClass();
llvm::Value *size, *alignMask;
getInstanceSizeAndAlignMask(IGF, selfType, theClass, selfValue,
size, alignMask);
selfValue = IGF.Builder.CreateBitCast(selfValue, IGF.IGM.RefCountedPtrTy);
emitDeallocatePartialClassInstance(IGF, selfValue, metadataValue,
size, alignMask);
}
llvm::Constant *irgen::tryEmitClassConstantFragileInstanceSize(
IRGenModule &IGM,
ClassDecl *Class) {
auto &classTI = getSelfTypeInfo(IGM, Class);
auto &layout = classTI.getLayout(IGM);
if (layout.isFixedLayout())
return layout.emitSize(IGM);
return nullptr;
}
llvm::Constant *irgen::tryEmitClassConstantFragileInstanceAlignMask(
IRGenModule &IGM,
ClassDecl *Class) {
auto &classTI = getSelfTypeInfo(IGM, Class);
auto &layout = classTI.getLayout(IGM);
if (layout.isFixedLayout())
return layout.emitAlignMask(IGM);
return nullptr;
}
/// emitClassDecl - Emit all the declarations associated with this class type.
void IRGenModule::emitClassDecl(ClassDecl *D) {
PrettyStackTraceDecl prettyStackTrace("emitting class metadata for", D);
auto &classTI = Types.getTypeInfo(D).as<ClassTypeInfo>();
// Emit the class metadata.
emitClassMetadata(*this, D,
classTI.getLayout(*this),
classTI.getClassLayout(*this));
emitNestedTypeDecls(D->getMembers());
addNominalTypeDecl(D);
}
namespace {
enum ForMetaClass_t : bool {
ForClass = false,
ForMetaClass = true
};
typedef std::pair<ClassDecl*, Module*> CategoryNameKey;
/// Used to provide unique names to ObjC categories generated by Swift
/// extensions. The first category for a class in a module gets the module's
/// name as its key, e.g., NSObject (MySwiftModule). Another extension of the
/// same class in the same module gets a category name with a number appended,
/// e.g., NSObject (MySwiftModule1).
llvm::DenseMap<CategoryNameKey, unsigned> CategoryCounts;
/// A class for building ObjC class data (in Objective-C terms, class_ro_t),
/// category data (category_t), or protocol data (protocol_t).
class ClassDataBuilder : public ClassMemberVisitor<ClassDataBuilder> {
IRGenModule &IGM;
PointerUnion<ClassDecl *, ProtocolDecl *> TheEntity;
ExtensionDecl *TheExtension;
const StructLayout *Layout;
const ClassLayout *FieldLayout;
ClassDecl *getClass() const {
return TheEntity.get<ClassDecl*>();
}
ProtocolDecl *getProtocol() const {
return TheEntity.get<ProtocolDecl*>();
}
bool isBuildingClass() const {
return TheEntity.is<ClassDecl*>() && !TheExtension;
}
bool isBuildingCategory() const {
return TheEntity.is<ClassDecl*>() && TheExtension;
}
bool isBuildingProtocol() const {
return TheEntity.is<ProtocolDecl*>();
}
bool HasNonTrivialDestructor = false;
bool HasNonTrivialConstructor = false;
llvm::SmallString<16> CategoryName;
SmallVector<llvm::Constant*, 8> Ivars;
SmallVector<llvm::Constant*, 16> InstanceMethods;
SmallVector<llvm::Constant*, 16> ClassMethods;
SmallVector<llvm::Constant*, 16> OptInstanceMethods;
SmallVector<llvm::Constant*, 16> OptClassMethods;
SmallVector<llvm::Constant*, 4> Protocols;
SmallVector<llvm::Constant*, 8> InstanceProperties;
SmallVector<llvm::Constant*, 8> ClassProperties;
SmallVector<llvm::Constant*, 8> InstanceMethodTypesExt;
SmallVector<llvm::Constant*, 8> ClassMethodTypesExt;
SmallVector<llvm::Constant*, 8> OptInstanceMethodTypesExt;
SmallVector<llvm::Constant*, 8> OptClassMethodTypesExt;
llvm::Constant *Name = nullptr;
/// Index of the first non-inherited field in the layout.
unsigned FirstFieldIndex;
unsigned NextFieldIndex;
public:
ClassDataBuilder(IRGenModule &IGM, ClassDecl *theClass,
const StructLayout &layout,
const ClassLayout &fieldLayout)
: IGM(IGM), TheEntity(theClass), TheExtension(nullptr),
Layout(&layout),
FieldLayout(&fieldLayout)
{
FirstFieldIndex = fieldLayout.InheritedStoredProperties.size();
NextFieldIndex = FirstFieldIndex;
visitConformances(theClass);
visitMembers(theClass);
if (Lowering::usesObjCAllocator(theClass)) {
addIVarInitializer();
addIVarDestroyer();
}
}
ClassDataBuilder(IRGenModule &IGM, ClassDecl *theClass,
ExtensionDecl *theExtension)
: IGM(IGM), TheEntity(theClass), TheExtension(theExtension),
Layout(nullptr), FieldLayout(nullptr)
{
FirstFieldIndex = -1;
NextFieldIndex = -1;
buildCategoryName(CategoryName);
visitConformances(theExtension);
for (Decl *member : TheExtension->getMembers())
visit(member);
}
ClassDataBuilder(IRGenModule &IGM, ProtocolDecl *theProtocol)
: IGM(IGM), TheEntity(theProtocol), TheExtension(nullptr)
{
// Gather protocol references for all of the explicitly-specified
// Objective-C protocol conformances.
// FIXME: We can't use visitConformances() because there are no
// conformances for protocols to protocols right now.
for (ProtocolDecl *p : theProtocol->getInheritedProtocols(nullptr)) {
if (!p->isObjC())
continue;
// Don't emit the magic AnyObject conformance.
if (p == IGM.Context.getProtocol(KnownProtocolKind::AnyObject))
continue;
Protocols.push_back(buildProtocolRef(p));
}
for (Decl *member : theProtocol->getMembers())
visit(member);
}
/// Gather protocol records for all of the explicitly-specified Objective-C
/// protocol conformances.
void visitConformances(DeclContext *dc) {
for (auto conformance : dc->getLocalConformances(
ConformanceLookupKind::OnlyExplicit,
nullptr, /*sorted=*/true)) {
ProtocolDecl *proto = conformance->getProtocol();
if (!proto->isObjC())
continue;
// Don't emit the magic AnyObject conformance.
if (auto known = proto->getKnownProtocolKind())
if (*known == KnownProtocolKind::AnyObject)
continue;
Protocols.push_back(buildProtocolRef(proto));
}
}
llvm::Constant *getMetaclassRefOrNull(ClassDecl *theClass) {
if (theClass->isGenericContext() && !theClass->hasClangNode()) {
return llvm::ConstantPointerNull::get(IGM.ObjCClassPtrTy);
} else {
return IGM.getAddrOfMetaclassObject(theClass, NotForDefinition);
}
}
void buildMetaclassStub() {
assert(Layout && "can't build a metaclass from a category");
// The isa is the metaclass pointer for the root class.
auto rootClass = getRootClassForMetaclass(IGM, TheEntity.get<ClassDecl *>());
auto rootPtr = getMetaclassRefOrNull(rootClass);
// The superclass of the metaclass is the metaclass of the
// superclass. Note that for metaclass stubs, we can always
// ignore parent contexts and generic arguments.
//
// If this class has no formal superclass, then its actual
// superclass is SwiftObject, i.e. the root class.
llvm::Constant *superPtr;
if (getClass()->hasSuperclass()) {
auto base = getClass()->getSuperclass()->getClassOrBoundGenericClass();
superPtr = getMetaclassRefOrNull(base);
} else {
superPtr = getMetaclassRefOrNull(
IGM.getObjCRuntimeBaseForSwiftRootClass(getClass()));
}
auto dataPtr = emitROData(ForMetaClass);
dataPtr = llvm::ConstantExpr::getPtrToInt(dataPtr, IGM.IntPtrTy);
llvm::Constant *fields[] = {
rootPtr,
superPtr,
IGM.getObjCEmptyCachePtr(),
IGM.getObjCEmptyVTablePtr(),
dataPtr
};
auto init = llvm::ConstantStruct::get(IGM.ObjCClassStructTy,
makeArrayRef(fields));
auto metaclass =
cast<llvm::GlobalVariable>(
IGM.getAddrOfMetaclassObject(getClass(), ForDefinition));
metaclass->setInitializer(init);
}
private:
void buildCategoryName(SmallVectorImpl<char> &s) {
llvm::raw_svector_ostream os(s);
// Find the module the extension is declared in.
Module *TheModule = TheExtension->getParentModule();
os << TheModule->getName();
unsigned categoryCount = CategoryCounts[{getClass(), TheModule}]++;
if (categoryCount > 0)
os << categoryCount;
}
public:
llvm::Constant *emitCategory() {
assert(TheExtension && "can't emit category data for a class");
llvm::Constant *fields[8];
// struct category_t {
// char const *name;
fields[0] = IGM.getAddrOfGlobalString(CategoryName);
// const class_t *theClass;
if (getClass()->hasClangNode())
fields[1] = IGM.getAddrOfObjCClass(getClass(), NotForDefinition);
else {
auto type = getSelfType(getClass()).getSwiftRValueType();
llvm::Constant *metadata =
tryEmitConstantHeapMetadataRef(IGM, type, /*allowUninit*/ true);
assert(metadata &&
"extended objc class doesn't have constant metadata?");
fields[1] = metadata;
}
// const method_list_t *instanceMethods;
fields[2] = buildInstanceMethodList();
// const method_list_t *classMethods;
fields[3] = buildClassMethodList();
// const protocol_list_t *baseProtocols;
fields[4] = buildProtocolList();
// const property_list_t *properties;
fields[5] = buildPropertyList(ForClass);
// const property_list_t *classProperties;
fields[6] = buildPropertyList(ForMetaClass);
// uint32_t size;
auto sizeofPointer = IGM.getPointerSize().getValue();
unsigned size = sizeofPointer * llvm::array_lengthof(fields);
// Adjust for 'size', which is always 32 bits rather than pointer-sized.
// FIXME: Clang does this by using non-ad-hoc types for ObjC runtime
// structures.
size -= (sizeofPointer - 4) * 1;
fields[7] = llvm::ConstantInt::get(IGM.Int32Ty, size);
// };
return buildGlobalVariable(fields, "_CATEGORY_");
}
llvm::Constant *emitProtocol() {
llvm::Constant *fields[13];
llvm::SmallString<64> nameBuffer;
assert(isBuildingProtocol() && "not emitting a protocol");
// struct protocol_t {
// Class super;
fields[0] = null();
// char const *name;
fields[1] = IGM.getAddrOfGlobalString(getEntityName(nameBuffer));
// const protocol_list_t *baseProtocols;
fields[2] = buildProtocolList();
// const method_list_t *requiredInstanceMethods;
fields[3] = buildInstanceMethodList();
// const method_list_t *requiredClassMethods;
fields[4] = buildClassMethodList();
// const method_list_t *optionalInstanceMethods;
fields[5] = buildOptInstanceMethodList();
// const method_list_t *optionalClassMethods;
fields[6] = buildOptClassMethodList();
// const property_list_t *properties;
fields[7] = buildPropertyList(ForClass);
// uint32_t size;
auto sizeofPointer = IGM.getPointerSize().getValue();
unsigned size = sizeofPointer * llvm::array_lengthof(fields);
// Adjust for 'size' and 'flags', which are always 32 bits rather than
// pointer-sized.
// FIXME: Clang does this by using non-ad-hoc types for ObjC runtime
// structures.
size -= (sizeofPointer - 4) * 2;
fields[8] = llvm::ConstantInt::get(IGM.Int32Ty, size);
// uint32_t flags;
auto flags = ProtocolDescriptorFlags()
.withSwift(!getProtocol()->hasClangNode())
.withClassConstraint(ProtocolClassConstraint::Class)
.withDispatchStrategy(ProtocolDispatchStrategy::ObjC)
.withSpecialProtocol(getSpecialProtocolID(getProtocol()));
fields[9] = llvm::ConstantInt::get(IGM.Int32Ty, flags.getIntValue());
// const char ** extendedMethodTypes;
fields[10] = buildOptExtendedMethodTypes();
// const char *demangledName;
fields[11] = null();
// const property_list_t *classProperties;
fields[12] = buildPropertyList(ForMetaClass);
// };
return buildGlobalVariable(fields, "_PROTOCOL_");
}
llvm::Constant *emitRODataFields(ForMetaClass_t forMeta) {
assert(Layout && "can't emit rodata for a category");
SmallVector<llvm::Constant*, 11> fields;
// struct _class_ro_t {
// uint32_t flags;
fields.push_back(buildFlags(forMeta));
// uint32_t instanceStart;
// uint32_t instanceSize;
// The runtime requires that the ivar offsets be initialized to
// a valid layout of the ivars of this class, bounded by these
// two values. If the instanceSize of the superclass equals the
// stored instanceStart of the subclass, the ivar offsets
// will not be changed.
Size instanceStart;
Size instanceSize;
if (forMeta) {
// sizeof(struct class_t)
instanceSize = Size(5 * IGM.getPointerSize().getValue());
// historical nonsense
instanceStart = instanceSize;
} else {
instanceSize = Layout->getSize();
if (Layout->getElements().empty()
|| Layout->getElements().size() == FirstFieldIndex) {
instanceStart = instanceSize;
} else if (Layout->getElement(FirstFieldIndex).getKind()
== ElementLayout::Kind::Fixed ||
Layout->getElement(FirstFieldIndex).getKind()
== ElementLayout::Kind::Empty) {
// FIXME: assumes layout is always sequential!
instanceStart = Layout->getElement(FirstFieldIndex).getByteOffset();
} else {
instanceStart = Size(0);
}
}
fields.push_back(llvm::ConstantInt::get(IGM.Int32Ty,
instanceStart.getValue()));
fields.push_back(llvm::ConstantInt::get(IGM.Int32Ty,
instanceSize.getValue()));
// uint32_t reserved; // only when building for 64bit targets
if (IGM.getPointerAlignment().getValue() > 4) {
assert(IGM.getPointerAlignment().getValue() == 8);
fields.push_back(llvm::ConstantInt::get(IGM.Int32Ty, 0));
}
// const uint8_t *ivarLayout;
// GC/ARC layout. TODO.
fields.push_back(null());
// const char *name;
// It is correct to use the same name for both class and metaclass.
fields.push_back(buildName());
// const method_list_t *baseMethods;
fields.push_back(forMeta ? buildClassMethodList()
: buildInstanceMethodList());
// const protocol_list_t *baseProtocols;
// Apparently, this list is the same in the class and the metaclass.
fields.push_back(buildProtocolList());
// const ivar_list_t *ivars;
fields.push_back(forMeta ? null() : buildIvarList());
// const uint8_t *weakIvarLayout;
// More GC/ARC layout. TODO.
fields.push_back(null());
// const property_list_t *baseProperties;
fields.push_back(buildPropertyList(forMeta));
// };
return llvm::ConstantStruct::getAnon(IGM.getLLVMContext(), fields);
}
llvm::Constant *emitROData(ForMetaClass_t forMeta) {
auto fields = emitRODataFields(forMeta);
auto dataSuffix = forMeta ? "_METACLASS_DATA_" : "_DATA_";
return buildGlobalVariable(fields, dataSuffix);
}
private:
llvm::Constant *buildFlags(ForMetaClass_t forMeta) {
ObjCClassFlags flags = ObjCClassFlags::CompiledByARC;
// Mark metaclasses as appropriate.
if (forMeta) {
flags |= ObjCClassFlags::Meta;
// Non-metaclasses need us to record things whether primitive
// construction/destructor is trivial.
} else if (HasNonTrivialDestructor || HasNonTrivialConstructor) {
flags |= ObjCClassFlags::HasCXXStructors;
if (!HasNonTrivialConstructor)
flags |= ObjCClassFlags::HasCXXDestructorOnly;
}
// FIXME: set ObjCClassFlags::Hidden when appropriate
return llvm::ConstantInt::get(IGM.Int32Ty, uint32_t(flags));
}
llvm::Constant *buildName() {
if (Name) return Name;
// If the class is generic, we'll instantiate its name at runtime.
if (getClass()->isGenericContext()) {
Name = llvm::ConstantPointerNull::get(IGM.Int8PtrTy);
return Name;
}
llvm::SmallString<64> buffer;
Name = IGM.getAddrOfGlobalString(getClass()->getObjCRuntimeName(buffer));
return Name;
}
llvm::Constant *null() {
return llvm::ConstantPointerNull::get(IGM.Int8PtrTy);
}
/*** Methods ***********************************************************/
public:
/// Methods need to be collected into the appropriate methods list.
void visitFuncDecl(FuncDecl *method) {
if (!isBuildingProtocol() &&
!requiresObjCMethodDescriptor(method)) return;
// getters and setters funcdecls will be handled by their parent
// var/subscript.
if (method->isAccessor()) return;
// Don't emit getters/setters for @NSManaged methods.
if (method->getAttrs().hasAttribute<NSManagedAttr>())
return;
llvm::Constant *entry = emitObjCMethodDescriptor(IGM, method);
// This pointer will be set if we need to store the extended method type
// encoding.
SmallVectorImpl<llvm::Constant *> *ExtMethodTypesList = nullptr;
if (!method->isStatic()) {
if (method->getAttrs().hasAttribute<OptionalAttr>()) {
OptInstanceMethods.push_back(entry);
if (isBuildingProtocol())
ExtMethodTypesList = &OptInstanceMethodTypesExt;
}
else {
InstanceMethods.push_back(entry);
if (isBuildingProtocol())
ExtMethodTypesList = &InstanceMethodTypesExt;
}
} else {
if (method->getAttrs().hasAttribute<OptionalAttr>()) {
OptClassMethods.push_back(entry);
if (isBuildingProtocol())
ExtMethodTypesList = &OptClassMethodTypesExt;
}
else {
ClassMethods.push_back(entry);
if (isBuildingProtocol())
ExtMethodTypesList = &ClassMethodTypesExt;
}
}
if (ExtMethodTypesList) {
ExtMethodTypesList->push_back(
getMethodTypeExtendedEncoding(IGM, method));
}
}
/// Constructors need to be collected into the appropriate methods list.
void visitConstructorDecl(ConstructorDecl *constructor) {
if (!isBuildingProtocol() &&
!requiresObjCMethodDescriptor(constructor)) return;
llvm::Constant *entry = emitObjCMethodDescriptor(IGM, constructor);
if (constructor->getAttrs().hasAttribute<OptionalAttr>()) {
OptInstanceMethods.push_back(entry);
if (isBuildingProtocol())
OptInstanceMethodTypesExt.push_back(
getMethodTypeExtendedEncoding(IGM, constructor));
} else {
InstanceMethods.push_back(entry);
if (isBuildingProtocol())
InstanceMethodTypesExt.push_back(
getMethodTypeExtendedEncoding(IGM, constructor));
}
}
/// Determine whether the given destructor has an Objective-C
/// definition.
bool hasObjCDeallocDefinition(DestructorDecl *destructor) {
// If we have the destructor body, we know whether SILGen
// generated a -dealloc body.
if (auto braceStmt = destructor->getBody())
return braceStmt->getNumElements() != 0;
// We don't have a destructor body, so hunt for the SIL function
// for it.
SILDeclRef dtorRef(destructor, SILDeclRef::Kind::Deallocator,
ResilienceExpansion::Minimal,
SILDeclRef::ConstructAtNaturalUncurryLevel,
/*isForeign=*/true);
if (auto silFn = IGM.SILMod->lookUpFunction(dtorRef))
return silFn->isDefinition();
// The Objective-C thunk was never even declared, so it is not defined.
return false;
}
/// Destructors need to be collected into the instance methods
/// list
void visitDestructorDecl(DestructorDecl *destructor) {
auto classDecl = cast<ClassDecl>(destructor->getDeclContext());
if (Lowering::usesObjCAllocator(classDecl) &&
hasObjCDeallocDefinition(destructor)) {
llvm::Constant *entry = emitObjCMethodDescriptor(IGM, destructor);
InstanceMethods.push_back(entry);
}
}
void addIVarInitializer() {
if (auto entry = emitObjCIVarInitDestroyDescriptor(IGM, getClass(),
false)) {
InstanceMethods.push_back(*entry);
HasNonTrivialConstructor = true;
}
}
void addIVarDestroyer() {
if (auto entry = emitObjCIVarInitDestroyDescriptor(IGM, getClass(),
true)) {
InstanceMethods.push_back(*entry);
HasNonTrivialDestructor = true;
}
}
private:
StringRef chooseNamePrefix(StringRef forClass,
StringRef forCategory,
StringRef forProtocol) {
if (isBuildingCategory())
return forCategory;
if (isBuildingClass())
return forClass;
if (isBuildingProtocol())
return forProtocol;
llvm_unreachable("not a class, category, or protocol?!");
}
llvm::Constant *buildClassMethodList() {
return buildMethodList(ClassMethods,
chooseNamePrefix("_CLASS_METHODS_",
"_CATEGORY_CLASS_METHODS_",
"_PROTOCOL_CLASS_METHODS_"));
}
llvm::Constant *buildInstanceMethodList() {
return buildMethodList(InstanceMethods,
chooseNamePrefix("_INSTANCE_METHODS_",
"_CATEGORY_INSTANCE_METHODS_",
"_PROTOCOL_INSTANCE_METHODS_"));
}
llvm::Constant *buildOptClassMethodList() {
return buildMethodList(OptClassMethods,
"_PROTOCOL_CLASS_METHODS_OPT_");
}
llvm::Constant *buildOptInstanceMethodList() {
return buildMethodList(OptInstanceMethods,
"_PROTOCOL_INSTANCE_METHODS_OPT_");
}
llvm::Constant *buildOptExtendedMethodTypes() {
SmallVector<llvm::Constant*, 16> AllMethodTypesExt;
assert(InstanceMethodTypesExt.size() == InstanceMethods.size()
&& "number of instance methods does not match extended types");
assert(ClassMethodTypesExt.size() == ClassMethods.size()
&& "number of class methods does not match extended types");
assert(OptInstanceMethodTypesExt.size() == OptInstanceMethods.size()
&& "number of optional instance methods does not match extended types");
assert(OptClassMethodTypesExt.size() == OptClassMethods.size()
&& "number of optional class methods does not match extended types");
AllMethodTypesExt.insert(AllMethodTypesExt.end(),
InstanceMethodTypesExt.begin(), InstanceMethodTypesExt.end());
AllMethodTypesExt.insert(AllMethodTypesExt.end(),
ClassMethodTypesExt.begin(), ClassMethodTypesExt.end());
AllMethodTypesExt.insert(AllMethodTypesExt.end(),
OptInstanceMethodTypesExt.begin(), OptInstanceMethodTypesExt.end());
AllMethodTypesExt.insert(AllMethodTypesExt.end(),
OptClassMethodTypesExt.begin(), OptClassMethodTypesExt.end());
return buildMethodList(AllMethodTypesExt,
"_PROTOCOL_METHOD_TYPES_");
}
/// struct method_list_t {
/// uint32_t entsize; // runtime uses low bits for its own purposes
/// uint32_t count;
/// method_t list[count];
/// };
///
/// This method does not return a value of a predictable type.
llvm::Constant *buildMethodList(ArrayRef<llvm::Constant*> methods,
StringRef name) {
return buildOptionalList(methods, 3 * IGM.getPointerSize(), name);
}
/*** Protocols *********************************************************/
/// typedef uintptr_t protocol_ref_t; // protocol_t*, but unremapped
llvm::Constant *buildProtocolRef(ProtocolDecl *protocol) {
assert(protocol->isObjC());
return IGM.getAddrOfObjCProtocolRecord(protocol, NotForDefinition);
}
/// struct protocol_list_t {
/// uintptr_t count;
/// protocol_ref_t[count];
/// };
///
/// This method does not return a value of a predictable type.
llvm::Constant *buildProtocolList() {
return buildOptionalList(Protocols, Size(0),
chooseNamePrefix("_PROTOCOLS_",
"_CATEGORY_PROTOCOLS_",
"_PROTOCOL_PROTOCOLS_"));
}
/*** Ivars *************************************************************/
public:
/// Variables might be stored or computed.
void visitVarDecl(VarDecl *var) {
if (var->hasStorage() && !var->isStatic())
visitStoredVar(var);
else
visitProperty(var);
}
private:
/// Ivars need to be collected in the ivars list, and they also
/// affect flags.
void visitStoredVar(VarDecl *var) {
// FIXME: how to handle ivar extensions in categories?
if (!Layout)
return;
// For now, we never try to emit specialized versions of the
// metadata statically, so compute the field layout using the
// originally-declared type.
SILType fieldType =
IGM.getLoweredType(IGM.SILMod->Types.getAbstractionPattern(var),
var->getType());
Ivars.push_back(buildIvar(var, fieldType));
// Build property accessors for the ivar if necessary.
visitProperty(var);
}
/// struct ivar_t {
/// uintptr_t *offset;
/// const char *name;
/// const char *type;
/// uint32_t alignment; // actually the log2 of the alignment
/// uint32_t size;
/// };
llvm::Constant *buildIvar(VarDecl *ivar, SILType loweredType) {
assert(Layout && "can't build ivar for category");
// FIXME: this is not always the right thing to do!
//auto &elt = Layout->getElement(NextFieldIndex++);
auto &ivarTI = IGM.getTypeInfo(loweredType);
llvm::Constant *offsetPtr;
switch (FieldLayout->AllFieldAccesses[NextFieldIndex++]) {
case FieldAccess::ConstantDirect:
case FieldAccess::NonConstantDirect: {
// If the field offset is fixed relative to the start of the superclass,
// reference the global from the ivar metadata so that the Objective-C
// runtime will slide it down.
auto offsetAddr = IGM.getAddrOfFieldOffset(ivar, /*indirect*/ false,
NotForDefinition);
offsetPtr = cast<llvm::Constant>(offsetAddr.getAddress());
break;
}
case FieldAccess::ConstantIndirect:
case FieldAccess::NonConstantIndirect:
// Otherwise, swift_initClassMetadata_UniversalStrategy() will point
// the Objective-C runtime into the field offset vector of the
// instantiated metadata.
offsetPtr
= llvm::ConstantPointerNull::get(IGM.IntPtrTy->getPointerTo());
break;
}
// TODO: clang puts this in __TEXT,__objc_methname,cstring_literals
auto name = IGM.getAddrOfGlobalString(ivar->getName().str());
// TODO: clang puts this in __TEXT,__objc_methtype,cstring_literals
auto typeEncode = IGM.getAddrOfGlobalString("");
Size size;
Alignment alignment;
if (auto fixedTI = dyn_cast<FixedTypeInfo>(&ivarTI)) {
size = fixedTI->getFixedSize();
alignment = fixedTI->getFixedAlignment();
} else {
// FIXME: set something up to fill these in at runtime!
size = Size(0);
alignment = Alignment(1);
}
// If the size is larger than we can represent in 32-bits,
// complain about the unimplementable ivar.
if (uint32_t(size.getValue()) != size.getValue()) {
IGM.error(ivar->getLoc(),
"ivar size (" + Twine(size.getValue()) +
" bytes) overflows Objective-C ivar layout");
size = Size(0);
}
llvm::Constant *fields[] = {
offsetPtr,
name,
typeEncode,
llvm::ConstantInt::get(IGM.Int32Ty, alignment.log2()),
llvm::ConstantInt::get(IGM.Int32Ty, size.getValue()),
};
return llvm::ConstantStruct::getAnon(IGM.getLLVMContext(), fields);
}
/// struct ivar_list_t {
/// uint32_t entsize;
/// uint32_t count;
/// ivar_t list[count];
/// };
///
/// This method does not return a value of a predictable type.
llvm::Constant *buildIvarList() {
Size eltSize = 3 * IGM.getPointerSize() + Size(8);
return buildOptionalList(Ivars, eltSize, "_IVARS_");
}
/*** Properties ********************************************************/
/// Properties need to be collected in the properties list.
void visitProperty(VarDecl *var) {
if (requiresObjCPropertyDescriptor(IGM, var)) {
if (llvm::Constant *prop = buildProperty(var)) {
auto &properties =
(var->isStatic() ? ClassProperties : InstanceProperties);
properties.push_back(prop);
}
// Don't emit getter/setter descriptors for @NSManaged properties.
if (var->getAttrs().hasAttribute<NSManagedAttr>() ||
// Don't emit descriptors for properties without accessors.
var->getGetter() == nullptr)
return;
SmallVectorImpl<llvm::Constant *> *methods;
SmallVectorImpl<llvm::Constant *> *extMethodTypes = nullptr;
if (var->getAttrs().hasAttribute<OptionalAttr>()) {
if (var->isStatic()) {
methods = &OptClassMethods;
if (isBuildingProtocol())
extMethodTypes = &OptClassMethodTypesExt;
} else {
methods = &OptInstanceMethods;
if (isBuildingProtocol())
extMethodTypes = &OptInstanceMethodTypesExt;
}
} else {
if (var->isStatic()) {
methods = &ClassMethods;
if (isBuildingProtocol())
extMethodTypes = &ClassMethodTypesExt;
} else {
methods = &InstanceMethods;
if (isBuildingProtocol())
extMethodTypes = &InstanceMethodTypesExt;
}
}
auto getter_setter = emitObjCPropertyMethodDescriptors(IGM, var);
methods->push_back(getter_setter.first);
if (getter_setter.second)
methods->push_back(getter_setter.second);
// Get the getter and setter extended encodings, if needed.
if (extMethodTypes) {
extMethodTypes->push_back(
getMethodTypeExtendedEncoding(IGM, var->getGetter()));
if (auto setter = var->getSetter()) {
assert(getter_setter.second && "no descriptor for setter?!");
extMethodTypes->push_back(
getMethodTypeExtendedEncoding(IGM, setter));
}
}
}
}
/// Build the property attribute string for a property decl.
void buildPropertyAttributes(VarDecl *prop, SmallVectorImpl<char> &out) {
llvm::raw_svector_ostream outs(out);
auto propTy = prop->getType()->getReferenceStorageReferent();
// Emit the type encoding for the property.
outs << 'T';
std::string typeEnc;
getObjCEncodingForPropertyType(IGM, prop, typeEnc);
outs << typeEnc;
// Emit other attributes.
// All Swift properties are (nonatomic).
outs << ",N";
// @NSManaged properties are @dynamic.
if (prop->getAttrs().hasAttribute<NSManagedAttr>())
outs << ",D";
auto isObject = propTy->hasRetainablePointerRepresentation();
auto hasObjectEncoding = typeEnc[0] == '@';
// Determine the assignment semantics.
// Get-only properties are (readonly).
if (!prop->isSettable(prop->getDeclContext()))
outs << ",R";
// Weak and Unowned properties are (weak).
else if (prop->getAttrs().hasAttribute<OwnershipAttr>())
outs << ",W";
// If the property is @NSCopying, or is bridged to a value class, the
// property is (copy).
else if (prop->getAttrs().hasAttribute<NSCopyingAttr>()
|| (hasObjectEncoding && !isObject))
outs << ",C";
// If it's of a managed object type, it is (retain).
else if (isObject)
outs << ",&";
// Otherwise, the property is of a value type, so it is
// the default (assign).
else
(void)0;
// If the property has storage, emit the ivar name last.
if (prop->hasStorage())
outs << ",V" << prop->getName();
}
/// struct property_t {
/// const char *name;
/// const char *attributes;
/// };
llvm::Constant *buildProperty(VarDecl *prop) {
llvm::SmallString<16> propertyAttributes;
buildPropertyAttributes(prop, propertyAttributes);
llvm::Constant *fields[] = {
IGM.getAddrOfGlobalString(prop->getObjCPropertyName().str()),
IGM.getAddrOfGlobalString(propertyAttributes)
};
return llvm::ConstantStruct::getAnon(IGM.getLLVMContext(), fields);
}
/// struct property_list_t {
/// uint32_t entsize;
/// uint32_t count;
/// property_t list[count];
/// };
///
/// This method does not return a value of a predictable type.
llvm::Constant *buildPropertyList(ForMetaClass_t classOrMeta) {
Size eltSize = 2 * IGM.getPointerSize();
StringRef namePrefix;
if (classOrMeta == ForClass) {
return buildOptionalList(InstanceProperties, eltSize,
chooseNamePrefix("_PROPERTIES_",
"_CATEGORY_PROPERTIES_",
"_PROTOCOL_PROPERTIES_"));
}
return buildOptionalList(ClassProperties, eltSize,
chooseNamePrefix("_CLASS_PROPERTIES_",
"_CATEGORY_CLASS_PROPERTIES_",
"_PROTOCOL_CLASS_PROPERTIES_"));
}
/*** General ***********************************************************/
/// Build a list structure from the given array of objects.
/// If the array is empty, use null. The assumption is that every
/// initializer has the same size.
///
/// \param optionalEltSize - if non-zero, a size which needs
/// to be placed in the list header
llvm::Constant *buildOptionalList(ArrayRef<llvm::Constant*> objects,
Size optionalEltSize,
StringRef nameBase) {
if (objects.empty())
return llvm::ConstantPointerNull::get(IGM.Int8PtrTy);
SmallVector<llvm::Constant*, 3> fields;
// FIXME. _PROTOCOL_METHOD_TYPES_ does not have the first two entries.
// May want to pull this into its own routine for performance; if needed.
if (!nameBase.equals("_PROTOCOL_METHOD_TYPES_")) {
// In all of the foo_list_t structs, either:
// - there's a 32-bit entry size and a 32-bit count or
// - there's no entry size and a uintptr_t count.
if (!optionalEltSize.isZero()) {
fields.push_back(llvm::ConstantInt::get(IGM.Int32Ty,
optionalEltSize.getValue()));
fields.push_back(llvm::ConstantInt::get(IGM.Int32Ty, objects.size()));
} else {
fields.push_back(llvm::ConstantInt::get(IGM.IntPtrTy, objects.size()));
}
}
auto arrayTy =
llvm::ArrayType::get(objects[0]->getType(), objects.size());
fields.push_back(llvm::ConstantArray::get(arrayTy, objects));
return buildGlobalVariable(fields, nameBase);
}
/// Get the name of the class or protocol to mangle into the ObjC symbol
/// name.
StringRef getEntityName(llvm::SmallVectorImpl<char> &buffer) const {
if (auto theClass = TheEntity.dyn_cast<ClassDecl*>()) {
return theClass->getObjCRuntimeName(buffer);
}
if (auto theProtocol = TheEntity.dyn_cast<ProtocolDecl*>()) {
return theProtocol->getObjCRuntimeName(buffer);
}
llvm_unreachable("not a class or protocol?!");
}
/// Build a private global variable as a structure containing the
/// given fields.
llvm::Constant *buildGlobalVariable(llvm::Constant *init,
StringRef nameBase) {
llvm::SmallString<64> nameBuffer;
auto var = new llvm::GlobalVariable(IGM.Module, init->getType(),
/*constant*/ true,
llvm::GlobalVariable::PrivateLinkage,
init,
Twine(nameBase)
+ getEntityName(nameBuffer)
+ (TheExtension
? Twine("_$_") + CategoryName.str()
: Twine()));
var->setAlignment(IGM.getPointerAlignment().getValue());
switch (IGM.TargetInfo.OutputObjectFormat) {
case llvm::Triple::MachO:
var->setSection("__DATA, __objc_const");
break;
case llvm::Triple::ELF:
var->setSection(".data");
break;
default:
llvm_unreachable("Don't know how to emit private global constants for "
"the selected object format.");
}
return var;
}
llvm::Constant *buildGlobalVariable(ArrayRef<llvm::Constant*> fields,
StringRef nameBase) {
auto init = llvm::ConstantStruct::getAnon(IGM.getLLVMContext(), fields);
return buildGlobalVariable(init, nameBase);
}
public:
/// Member types don't get any representation.
/// Maybe this should change for reflection purposes?
void visitTypeDecl(TypeDecl *type) {}
/// Pattern-bindings don't require anything special as long as
/// these initializations are performed in the constructor, not
/// .cxx_construct.
void visitPatternBindingDecl(PatternBindingDecl *binding) {}
/// Subscripts should probably be collected in extended metadata.
void visitSubscriptDecl(SubscriptDecl *subscript) {
if (!requiresObjCSubscriptDescriptor(IGM, subscript)) return;
auto getter_setter = emitObjCSubscriptMethodDescriptors(IGM, subscript);
if (subscript->getAttrs().hasAttribute<OptionalAttr>()) {
OptInstanceMethods.push_back(getter_setter.first);
if (isBuildingProtocol())
OptInstanceMethodTypesExt.push_back(
getMethodTypeExtendedEncoding(IGM, subscript->getGetter()));
} else {
InstanceMethods.push_back(getter_setter.first);
if (isBuildingProtocol())
InstanceMethodTypesExt.push_back(
getMethodTypeExtendedEncoding(IGM, subscript->getGetter()));
}
if (getter_setter.second) {
assert(subscript->getSetter() && "no descriptor for setter?!");
if (subscript->getAttrs().hasAttribute<OptionalAttr>()) {
OptInstanceMethods.push_back(getter_setter.second);
if (isBuildingProtocol())
OptInstanceMethodTypesExt.push_back(
getMethodTypeExtendedEncoding(IGM, subscript->getSetter()));
} else {
InstanceMethods.push_back(getter_setter.second);
if (isBuildingProtocol())
InstanceMethodTypesExt.push_back(
getMethodTypeExtendedEncoding(IGM, subscript->getSetter()));
}
}
}
};
}
/// Emit the private data (RO-data) associated with a class.
llvm::Constant *irgen::emitClassPrivateData(IRGenModule &IGM,
ClassDecl *cls) {
assert(IGM.ObjCInterop && "emitting RO-data outside of interop mode");
SILType selfType = getSelfType(cls);
auto &classTI = IGM.getTypeInfo(selfType).as<ClassTypeInfo>();
auto &layout = classTI.getLayout(IGM);
auto &fieldLayout = classTI.getClassLayout(IGM);
ClassDataBuilder builder(IGM, cls, layout, fieldLayout);
// First, build the metaclass object.
builder.buildMetaclassStub();
// Then build the class RO-data.
return builder.emitROData(ForClass);
}
std::tuple<llvm::Constant * /*classData*/,
llvm::Constant * /*metaclassData*/,
Size>
irgen::emitClassPrivateDataFields(IRGenModule &IGM, ClassDecl *cls) {
assert(IGM.ObjCInterop && "emitting RO-data outside of interop mode");
SILType selfType = getSelfType(cls);
auto &classTI = IGM.getTypeInfo(selfType).as<ClassTypeInfo>();
auto &layout = classTI.getLayout(IGM);
auto &fieldLayout = classTI.getClassLayout(IGM);
ClassDataBuilder builder(IGM, cls, layout, fieldLayout);
auto classFields = builder.emitRODataFields(ForClass);
auto metaclassFields = builder.emitRODataFields(ForMetaClass);
Size size(IGM.DataLayout.getTypeAllocSize(classFields->getType()));
return std::make_tuple(classFields, metaclassFields, size);
}
/// Emit the metadata for an ObjC category.
llvm::Constant *irgen::emitCategoryData(IRGenModule &IGM,
ExtensionDecl *ext) {
assert(IGM.ObjCInterop && "emitting RO-data outside of interop mode");
ClassDecl *cls = ext->getAsClassOrClassExtensionContext();
assert(cls && "generating category metadata for a non-class extension");
ClassDataBuilder builder(IGM, cls, ext);
return builder.emitCategory();
}
/// Emit the metadata for an ObjC protocol.
llvm::Constant *irgen::emitObjCProtocolData(IRGenModule &IGM,
ProtocolDecl *proto) {
assert(proto->isObjC() && "not an objc protocol");
ClassDataBuilder builder(IGM, proto);
return builder.emitProtocol();
}
const TypeInfo *TypeConverter::convertClassType(ClassDecl *D) {
llvm::StructType *ST = IGM.createNominalType(D);
llvm::PointerType *irType = ST->getPointerTo();
ReferenceCounting refcount = ::getReferenceCountingForClass(IGM, D);
SpareBitVector spareBits;
// Classes known to be implemented in Swift can be assumed not to have tagged
// pointer representations, so we can use spare bits for enum layout with
// them. We can't make that assumption about imported ObjC types.
if (D->hasClangNode() && IGM.TargetInfo.hasObjCTaggedPointers())
spareBits.appendClearBits(IGM.getPointerSize().getValueInBits());
else
spareBits = IGM.getHeapObjectSpareBits();
return new ClassTypeInfo(irType, IGM.getPointerSize(),
std::move(spareBits),
IGM.getPointerAlignment(),
D, refcount);
}
/// Lazily declare a fake-looking class to represent an ObjC runtime base class.
ClassDecl *IRGenModule::getObjCRuntimeBaseClass(Identifier name,
Identifier objcName) {
auto found = SwiftRootClasses.find(name);
if (found != SwiftRootClasses.end())
return found->second;
// Make a really fake-looking class.
auto SwiftRootClass = new (Context) ClassDecl(SourceLoc(), name, SourceLoc(),
MutableArrayRef<TypeLoc>(),
/*generics*/ nullptr,
Context.TheBuiltinModule);
SwiftRootClass->computeType();
SwiftRootClass->setIsObjC(true);
SwiftRootClass->getAttrs().add(ObjCAttr::createNullary(Context, objcName,
/*implicit=*/true));
SwiftRootClass->setImplicit();
SwiftRootClass->setAccessibility(Accessibility::Public);
SwiftRootClasses.insert({name, SwiftRootClass});
return SwiftRootClass;
}
/// Lazily declare the ObjC runtime base class for a Swift root class.
ClassDecl *
IRGenModule::getObjCRuntimeBaseForSwiftRootClass(ClassDecl *theClass) {
assert(!theClass->hasSuperclass() && "must pass a root class");
Identifier name;
// If the class declares its own ObjC runtime base, use it.
if (auto baseAttr = theClass->getAttrs()
.getAttribute<SwiftNativeObjCRuntimeBaseAttr>()) {
name = baseAttr->BaseClassName;
} else {
// Otherwise, use the standard SwiftObject class.
name = Context.Id_SwiftObject;
}
return getObjCRuntimeBaseClass(name, name);
}
ClassDecl *irgen::getRootClassForMetaclass(IRGenModule &IGM, ClassDecl *C) {
while (auto superclass = C->getSuperclass())
C = superclass->getClassOrBoundGenericClass();
// If the formal root class is imported from Objective-C, then
// we should use that. For a class that's really implemented in
// Objective-C, this is obviously right. For a class that's
// really implemented in Swift, but that we're importing via an
// Objective-C interface, this would be wrong --- except such a
// class can never be a formal root class, because a Swift class
// without a formal superclass will actually be parented by
// SwiftObject (or maybe eventually something else like it),
// which will be visible in the Objective-C type system.
if (C->hasClangNode()) return C;
// FIXME: If the root class specifies its own runtime ObjC base class,
// assume that that base class ultimately inherits NSObject.
if (C->getAttrs().hasAttribute<SwiftNativeObjCRuntimeBaseAttr>())
return IGM.getObjCRuntimeBaseClass(
IGM.Context.getSwiftId(KnownFoundationEntity::NSObject),
IGM.Context.getIdentifier("NSObject"));
return IGM.getObjCRuntimeBaseClass(IGM.Context.Id_SwiftObject,
IGM.Context.Id_SwiftObject);
}
bool irgen::doesClassMetadataRequireDynamicInitialization(IRGenModule &IGM,
ClassDecl *theClass) {
// Classes imported from Objective-C never requires dynamic initialization.
if (theClass->hasClangNode())
return false;
auto &layout = getSelfTypeInfo(IGM, theClass).getClassLayout(IGM);
return layout.MetadataRequiresDynamicInitialization;
}
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