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//===--- GenMeta.cpp - IR generation for metadata constructs --------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements IR generation for type metadata constructs.
//
//===----------------------------------------------------------------------===//
#include "swift/ABI/MetadataValues.h"
#include "swift/ABI/TypeIdentity.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/ASTMangler.h"
#include "swift/AST/CanTypeVisitor.h"
#include "swift/AST/Decl.h"
#include "swift/AST/Attr.h"
#include "swift/AST/IRGenOptions.h"
#include "swift/AST/PrettyStackTrace.h"
#include "swift/AST/SubstitutionMap.h"
#include "swift/AST/Types.h"
#include "swift/ClangImporter/ClangModule.h"
#include "swift/IRGen/Linking.h"
#include "swift/SIL/FormalLinkage.h"
#include "swift/SIL/SILModule.h"
#include "swift/SIL/TypeLowering.h"
#include "swift/Strings.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Module.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclObjC.h"
#include "Address.h"
#include "Callee.h"
#include "ClassLayout.h"
#include "ClassMetadataVisitor.h"
#include "ConstantBuilder.h"
#include "EnumMetadataVisitor.h"
#include "FixedTypeInfo.h"
#include "ForeignClassMetadataVisitor.h"
#include "GenArchetype.h"
#include "GenClass.h"
#include "GenDecl.h"
#include "GenPoly.h"
#include "GenStruct.h"
#include "GenValueWitness.h"
#include "HeapTypeInfo.h"
#include "IRGenDebugInfo.h"
#include "IRGenMangler.h"
#include "IRGenModule.h"
#include "MetadataLayout.h"
#include "MetadataRequest.h"
#include "ProtocolInfo.h"
#include "ScalarTypeInfo.h"
#include "StructLayout.h"
#include "StructMetadataVisitor.h"
#include "GenMeta.h"
using namespace swift;
using namespace irgen;
static Address emitAddressOfMetadataSlotAtIndex(IRGenFunction &IGF,
llvm::Value *metadata,
int index,
llvm::Type *objectTy) {
// Require the metadata to be some type that we recognize as a
// metadata pointer.
assert(metadata->getType() == IGF.IGM.TypeMetadataPtrTy);
return IGF.emitAddressAtOffset(metadata,
Offset(index * IGF.IGM.getPointerSize()),
objectTy, IGF.IGM.getPointerAlignment());
}
/// Emit a load from the given metadata at a constant index.
static llvm::LoadInst *emitLoadFromMetadataAtIndex(IRGenFunction &IGF,
llvm::Value *metadata,
int index,
llvm::Type *objectTy,
const llvm::Twine &suffix = "") {
Address slot =
emitAddressOfMetadataSlotAtIndex(IGF, metadata, index, objectTy);
// Load.
return IGF.Builder.CreateLoad(slot, metadata->getName() + suffix);
}
static Address createPointerSizedGEP(IRGenFunction &IGF,
Address base,
Size offset) {
return IGF.Builder.CreateConstArrayGEP(base,
IGF.IGM.getOffsetInWords(offset),
offset);
}
void IRGenModule::setTrueConstGlobal(llvm::GlobalVariable *var) {
disableAddressSanitizer(*this, var);
switch (TargetInfo.OutputObjectFormat) {
case llvm::Triple::UnknownObjectFormat:
llvm_unreachable("unknown object format");
case llvm::Triple::MachO:
var->setSection("__TEXT,__const");
break;
case llvm::Triple::ELF:
var->setSection(".rodata");
break;
case llvm::Triple::COFF:
var->setSection(".rdata");
break;
case llvm::Triple::Wasm:
var->setSection(".rodata");
break;
}
}
/*****************************************************************************/
/** Metadata completion ******************************************************/
/*****************************************************************************/
/// Does the metadata for the given type, which we are currently emitting,
/// require singleton metadata initialization structures and functions?
static bool needsSingletonMetadataInitialization(IRGenModule &IGM,
NominalTypeDecl *typeDecl) {
// Generic types never have singleton metadata initialization.
if (typeDecl->isGenericContext())
return false;
// Non-generic classes use singleton initialization if they have anything
// non-trivial about their metadata.
if (auto *classDecl = dyn_cast<ClassDecl>(typeDecl)) {
switch (IGM.getClassMetadataStrategy(classDecl)) {
case ClassMetadataStrategy::Resilient:
case ClassMetadataStrategy::Singleton:
case ClassMetadataStrategy::Update:
case ClassMetadataStrategy::FixedOrUpdate:
return true;
case ClassMetadataStrategy::Fixed:
return false;
}
}
assert(isa<StructDecl>(typeDecl) || isa<EnumDecl>(typeDecl));
// If the type is known to be fixed-layout, we can emit its metadata such
// that it doesn't need dynamic initialization.
auto &ti = IGM.getTypeInfoForUnlowered(typeDecl->getDeclaredTypeInContext());
if (ti.isFixedSize(ResilienceExpansion::Maximal))
return false;
return true;
}
using MetadataCompletionBodyEmitter =
void (IRGenFunction &IGF,
llvm::Value *metadata,
MetadataDependencyCollector *collector);
static void emitMetadataCompletionFunction(IRGenModule &IGM,
NominalTypeDecl *typeDecl,
llvm::function_ref<MetadataCompletionBodyEmitter> body) {
llvm::Function *f =
IGM.getAddrOfTypeMetadataCompletionFunction(typeDecl, ForDefinition);
f->setAttributes(IGM.constructInitialAttributes());
f->setDoesNotThrow();
IGM.setHasFramePointer(f, false);
IRGenFunction IGF(IGM, f);
// Skip instrumentation when building for TSan to avoid false positives.
// The synchronization for this happens in the Runtime and we do not see it.
if (IGM.IRGen.Opts.Sanitizers & SanitizerKind::Thread)
f->removeFnAttr(llvm::Attribute::SanitizeThread);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, f);
Explosion params = IGF.collectParameters();
llvm::Value *metadata = params.claimNext();
llvm::Value *context = params.claimNext();
llvm::Value *templatePointer = params.claimNext();
// TODO: use these?
(void) context;
(void) templatePointer;
MetadataDependencyCollector collector;
body(IGF, metadata, &collector);
// At the current insertion point, the metadata is now complete.
// Merge with any metadata dependencies we may have collected.
auto dependency = collector.finish(IGF);
auto returnValue = dependency.combine(IGF);
IGF.Builder.CreateRet(returnValue);
}
static bool needsForeignMetadataCompletionFunction(IRGenModule &IGM,
StructDecl *decl) {
// Currently, foreign structs never need a completion function.
return false;
}
static bool needsForeignMetadataCompletionFunction(IRGenModule &IGM,
EnumDecl *decl) {
// Currently, foreign enums never need a completion function.
return false;
}
static bool needsForeignMetadataCompletionFunction(IRGenModule &IGM,
ClassDecl *decl) {
return IGM.getOptions().LazyInitializeClassMetadata || decl->hasSuperclass();
}
/*****************************************************************************/
/** Nominal Type Descriptor Emission *****************************************/
/*****************************************************************************/
template <class Flags>
static Flags getMethodDescriptorFlags(ValueDecl *fn) {
if (isa<ConstructorDecl>(fn))
return Flags(Flags::Kind::Init); // 'init' is considered static
auto kind = [&] {
auto accessor = dyn_cast<AccessorDecl>(fn);
if (!accessor) return Flags::Kind::Method;
switch (accessor->getAccessorKind()) {
case AccessorKind::Get:
return Flags::Kind::Getter;
case AccessorKind::Set:
return Flags::Kind::Setter;
case AccessorKind::Read:
return Flags::Kind::ReadCoroutine;
case AccessorKind::Modify:
return Flags::Kind::ModifyCoroutine;
#define OPAQUE_ACCESSOR(ID, KEYWORD)
#define ACCESSOR(ID) \
case AccessorKind::ID:
#include "swift/AST/AccessorKinds.def"
llvm_unreachable("these accessors never appear in protocols or v-tables");
}
llvm_unreachable("bad kind");
}();
return Flags(kind).withIsInstance(!fn->isStatic());
}
namespace {
template<class Impl>
class ContextDescriptorBuilderBase {
protected:
Impl &asImpl() { return *static_cast<Impl*>(this); }
IRGenModule &IGM;
private:
ConstantInitBuilder InitBuilder;
protected:
ConstantStructBuilder B;
Optional<ConstantAggregateBuilderBase::PlaceholderPosition>
GenericParamCount,
GenericRequirementCount,
GenericKeyArgumentCount,
GenericExtraArgumentCount;
unsigned NumGenericKeyArguments = 0;
unsigned NumGenericExtraArguments = 0;
ContextDescriptorBuilderBase(IRGenModule &IGM)
: IGM(IGM), InitBuilder(IGM), B(InitBuilder.beginStruct()) {
B.setPacked(true);
}
public:
void layout() {
asImpl().addFlags();
asImpl().addParent();
}
void addFlags() {
B.addInt32(
ContextDescriptorFlags(asImpl().getContextKind(),
asImpl().getGenericSignature() != nullptr,
asImpl().isUniqueDescriptor(),
asImpl().getVersion(),
asImpl().getKindSpecificFlags())
.getIntValue());
}
void addParent() {
ConstantReference parent = asImpl().getParent();
if (parent.getValue()) {
B.addRelativeAddress(parent);
} else {
B.addInt32(0); // null offset
}
}
void addGenericSignature() {
if (!asImpl().getGenericSignature())
return;
asImpl().addGenericParametersHeader();
asImpl().addGenericParameters();
asImpl().addGenericRequirements();
asImpl().finishGenericParameters();
}
void addGenericParametersHeader() {
// Drop placeholders for the counts. We'll fill these in when we emit
// the related sections.
GenericParamCount = B.addPlaceholderWithSize(IGM.Int16Ty);
GenericRequirementCount = B.addPlaceholderWithSize(IGM.Int16Ty);
GenericKeyArgumentCount = B.addPlaceholderWithSize(IGM.Int16Ty);
GenericExtraArgumentCount = B.addPlaceholderWithSize(IGM.Int16Ty);
}
void addGenericParameters() {
GenericSignature *sig = asImpl().getGenericSignature();
assert(sig);
auto canSig = sig->getCanonicalSignature();
canSig->forEachParam([&](GenericTypeParamType *param, bool canonical) {
// Currently, there are only type parameters. The parameter is a key
// argument if it's canonical in its generic context.
asImpl().addGenericParameter(GenericParamKind::Type,
/*key argument*/ canonical,
/*extra argument*/ false);
});
// Pad the structure up to four bytes for the following requirements.
unsigned padding = (unsigned) -canSig->getGenericParams().size() & 3;
for (unsigned i = 0; i < padding; ++i)
B.addInt(IGM.Int8Ty, 0);
// Fill in the parameter count.
assert(canSig->getGenericParams().size() <= UINT16_MAX
&& "way too generic");
B.fillPlaceholderWithInt(*GenericParamCount, IGM.Int16Ty,
canSig->getGenericParams().size());
}
void addGenericParameter(GenericParamKind kind,
bool isKeyArgument, bool isExtraArgument) {
if (isKeyArgument)
++NumGenericKeyArguments;
if (isExtraArgument)
++NumGenericExtraArguments;
B.addInt(IGM.Int8Ty,
GenericParamDescriptor(kind, isKeyArgument, isExtraArgument)
.getIntValue());
}
void addGenericRequirements() {
auto metadata =
irgen::addGenericRequirements(IGM, B,
asImpl().getGenericSignature(),
asImpl().getGenericSignature()->getRequirements());
// Fill in the final requirement count.
assert(metadata.NumRequirements <= UINT16_MAX
&& "way too generic");
B.fillPlaceholderWithInt(*GenericRequirementCount, IGM.Int16Ty,
metadata.NumRequirements);
NumGenericKeyArguments += metadata.NumGenericKeyArguments;
NumGenericExtraArguments += metadata.NumGenericExtraArguments;
}
void finishGenericParameters() {
assert(NumGenericKeyArguments <= UINT16_MAX
&& NumGenericExtraArguments <= UINT16_MAX
&& "way too generic");
B.fillPlaceholderWithInt(*GenericKeyArgumentCount, IGM.Int16Ty,
NumGenericKeyArguments);
B.fillPlaceholderWithInt(*GenericExtraArgumentCount, IGM.Int16Ty,
NumGenericExtraArguments);
}
uint8_t getVersion() {
return 0;
}
uint16_t getKindSpecificFlags() {
return 0;
}
// Subclasses should provide:
//
// bool isUniqueDescriptor();
// llvm::Constant *getParent();
// ContextDescriptorKind getContextKind();
// GenericSignature *getGenericSignature();
// void emit();
};
class ModuleContextDescriptorBuilder
: public ContextDescriptorBuilderBase<ModuleContextDescriptorBuilder> {
using super = ContextDescriptorBuilderBase;
ModuleDecl *M;
public:
ModuleContextDescriptorBuilder(IRGenModule &IGM, ModuleDecl *M)
: super(IGM), M(M)
{}
void layout() {
super::layout();
addName();
}
void addName() {
B.addRelativeAddress(IGM.getAddrOfGlobalString(M->getName().str(),
/*willBeRelativelyAddressed*/ true));
}
bool isUniqueDescriptor() {
return false;
}
ConstantReference getParent() {
return {nullptr, ConstantReference::Direct};
}
ContextDescriptorKind getContextKind() {
return ContextDescriptorKind::Module;
}
GenericSignature *getGenericSignature() {
return nullptr;
}
void emit() {
asImpl().layout();
auto addr = IGM.getAddrOfModuleContextDescriptor(M,
B.finishAndCreateFuture());
auto var = cast<llvm::GlobalVariable>(addr);
var->setConstant(true);
IGM.setTrueConstGlobal(var);
}
};
class ExtensionContextDescriptorBuilder
: public ContextDescriptorBuilderBase<ExtensionContextDescriptorBuilder> {
using super = ContextDescriptorBuilderBase;
ExtensionDecl *E;
public:
ExtensionContextDescriptorBuilder(IRGenModule &IGM, ExtensionDecl *E)
: super(IGM), E(E)
{}
void layout() {
super::layout();
addExtendedContext();
addGenericSignature();
}
void addExtendedContext() {
auto string = IGM.getTypeRef(E->getSelfInterfaceType(),
E->getGenericSignature(),
MangledTypeRefRole::Metadata).first;
B.addRelativeAddress(string);
}
ConstantReference getParent() {
return {IGM.getAddrOfModuleContextDescriptor(E->getParentModule()),
ConstantReference::Direct};
}
bool isUniqueDescriptor() {
// Extensions generated by the Clang importer will be emitted into any
// binary that uses the Clang module. Otherwise, we can guarantee that
// an extension (and any of its possible sub-contexts) belong to one
// translation unit.
return !isa<ClangModuleUnit>(E->getModuleScopeContext());
}
ContextDescriptorKind getContextKind() {
return ContextDescriptorKind::Extension;
}
GenericSignature *getGenericSignature() {
return E->getGenericSignature();
}
void emit() {
asImpl().layout();
auto addr = IGM.getAddrOfExtensionContextDescriptor(E,
B.finishAndCreateFuture());
auto var = cast<llvm::GlobalVariable>(addr);
var->setConstant(true);
IGM.setTrueConstGlobal(var);
}
};
class AnonymousContextDescriptorBuilder
: public ContextDescriptorBuilderBase<AnonymousContextDescriptorBuilder> {
using super = ContextDescriptorBuilderBase;
PointerUnion<DeclContext *, VarDecl *> Name;
DeclContext *getInnermostDeclContext() {
if (auto DC = Name.dyn_cast<DeclContext *>()) {
return DC;
}
if (auto VD = Name.dyn_cast<VarDecl *>()) {
return VD->getInnermostDeclContext();
}
llvm_unreachable("unknown name kind");
}
public:
AnonymousContextDescriptorBuilder(IRGenModule &IGM,
PointerUnion<DeclContext *, VarDecl *> Name)
: super(IGM), Name(Name)
{
}
void layout() {
super::layout();
asImpl().addGenericSignature();
asImpl().addMangledName();
}
ConstantReference getParent() {
return IGM.getAddrOfParentContextDescriptor(
getInnermostDeclContext(), /*fromAnonymousContext=*/true);
}
ContextDescriptorKind getContextKind() {
return ContextDescriptorKind::Anonymous;
}
GenericSignature *getGenericSignature() {
return getInnermostDeclContext()->getGenericSignatureOfContext();
}
bool isUniqueDescriptor() {
return true;
}
uint16_t getKindSpecificFlags() {
AnonymousContextDescriptorFlags flags{};
flags.setHasMangledName(
IGM.IRGen.Opts.EnableAnonymousContextMangledNames);
return flags.getOpaqueValue();
}
void addMangledName() {
if (!IGM.IRGen.Opts.EnableAnonymousContextMangledNames)
return;
IRGenMangler mangler;
auto mangledName = mangler.mangleAnonymousDescriptorName(Name);
auto mangledNameConstant =
IGM.getAddrOfGlobalString(mangledName,
/*willBeRelativelyAddressed*/ true);
B.addRelativeAddress(mangledNameConstant);
}
void emit() {
asImpl().layout();
auto addr = IGM.getAddrOfAnonymousContextDescriptor(Name,
B.finishAndCreateFuture());
auto var = cast<llvm::GlobalVariable>(addr);
var->setConstant(true);
IGM.setTrueConstGlobal(var);
}
};
class ProtocolDescriptorBuilder
: public ContextDescriptorBuilderBase<ProtocolDescriptorBuilder> {
using super = ContextDescriptorBuilderBase;
ProtocolDecl *Proto;
SILDefaultWitnessTable *DefaultWitnesses;
Optional<ConstantAggregateBuilderBase::PlaceholderPosition>
NumRequirementsInSignature,
NumRequirements;
bool Resilient;
public:
ProtocolDescriptorBuilder(IRGenModule &IGM, ProtocolDecl *Proto,
SILDefaultWitnessTable *defaultWitnesses)
: super(IGM), Proto(Proto), DefaultWitnesses(defaultWitnesses),
Resilient(IGM.isResilient(Proto, ResilienceExpansion::Minimal)) {}
void layout() {
super::layout();
}
ConstantReference getParent() {
return IGM.getAddrOfParentContextDescriptor(
Proto, /*fromAnonymousContext=*/false);
}
ContextDescriptorKind getContextKind() {
return ContextDescriptorKind::Protocol;
}
GenericSignature *getGenericSignature() {
return nullptr;
}
bool isUniqueDescriptor() {
return true;
}
uint16_t getKindSpecificFlags() {
ProtocolContextDescriptorFlags flags;
flags.setClassConstraint(Proto->requiresClass()
? ProtocolClassConstraint::Class
: ProtocolClassConstraint::Any);
flags.setSpecialProtocol(getSpecialProtocolID(Proto));
flags.setIsResilient(DefaultWitnesses != nullptr);
return flags.getOpaqueValue();
}
void emit() {
asImpl().layout();
asImpl().addName();
NumRequirementsInSignature = B.addPlaceholderWithSize(IGM.Int32Ty);
NumRequirements = B.addPlaceholderWithSize(IGM.Int32Ty);
asImpl().addAssociatedTypeNames();
asImpl().addRequirementSignature();
asImpl().addRequirements();
auto addr = IGM.getAddrOfProtocolDescriptor(Proto,
B.finishAndCreateFuture());
auto var = cast<llvm::GlobalVariable>(addr);
var->setConstant(true);
IGM.setTrueConstGlobal(var);
}
void addName() {
auto nameStr = IGM.getAddrOfGlobalString(Proto->getName().str(),
/*willBeRelativelyAddressed*/ true);
B.addRelativeAddress(nameStr);
}
void addRequirementSignature() {
auto metadata =
irgen::addGenericRequirements(IGM, B, Proto->getGenericSignature(),
Proto->getRequirementSignature());
B.fillPlaceholderWithInt(*NumRequirementsInSignature, IGM.Int32Ty,
metadata.NumRequirements);
}
struct RequirementInfo {
ProtocolRequirementFlags Flags;
llvm::Constant *DefaultImpl;
};
/// Build the information which will go into a ProtocolRequirement entry.
RequirementInfo getRequirementInfo(const WitnessTableEntry &entry) {
using Flags = ProtocolRequirementFlags;
if (entry.isBase()) {
assert(entry.isOutOfLineBase());
auto flags = Flags(Flags::Kind::BaseProtocol);
return { flags, nullptr };
}
if (entry.isAssociatedType()) {
auto flags = Flags(Flags::Kind::AssociatedTypeAccessFunction);
// Look for a default witness.
llvm::Constant *defaultImpl =
findDefaultTypeWitness(entry.getAssociatedType());
return { flags, defaultImpl };
}
if (entry.isAssociatedConformance()) {
auto flags = Flags(Flags::Kind::AssociatedConformanceAccessFunction);
// Look for a default witness.
llvm::Constant *defaultImpl =
findDefaultAssociatedConformanceWitness(
entry.getAssociatedConformancePath(),
entry.getAssociatedConformanceRequirement());
return { flags, defaultImpl };
}
assert(entry.isFunction());
SILDeclRef func(entry.getFunction());
// Emit the dispatch thunk.
if (Resilient)
IGM.emitDispatchThunk(func);
// Classify the function.
auto flags = getMethodDescriptorFlags<Flags>(func.getDecl());
// Look for a default witness.
llvm::Constant *defaultImpl = findDefaultWitness(func);
return { flags, defaultImpl };
}
void addRequirements() {
auto &pi = IGM.getProtocolInfo(Proto, ProtocolInfoKind::Full);
B.fillPlaceholderWithInt(*NumRequirements, IGM.Int32Ty,
pi.getNumWitnesses());
if (pi.getNumWitnesses() > 0) {
// Define the protocol requirements "base" descriptor, which references
// the beginning of the protocol requirements, offset so that
// subtracting this address from the address of a given protocol
// requirements gives the corresponding offset into the witness
// table.
auto address =
B.getAddrOfCurrentPosition(IGM.ProtocolRequirementStructTy);
int offset = WitnessTableFirstRequirementOffset;
auto firstReqAdjustment = llvm::ConstantInt::get(IGM.Int32Ty, -offset);
address = llvm::ConstantExpr::getGetElementPtr(nullptr, address,
firstReqAdjustment);
IGM.defineProtocolRequirementsBaseDescriptor(Proto, address);
}
for (auto &entry : pi.getWitnessEntries()) {
if (Resilient) {
if (entry.isFunction()) {
// Define the method descriptor.
SILDeclRef func(entry.getFunction());
auto *descriptor =
B.getAddrOfCurrentPosition(
IGM.ProtocolRequirementStructTy);
IGM.defineMethodDescriptor(func, Proto, descriptor);
}
}
if (entry.isAssociatedType()) {
auto assocType = entry.getAssociatedType();
// Define the associated type descriptor to point to the current
// position in the protocol descriptor.
IGM.defineAssociatedTypeDescriptor(
assocType,
B.getAddrOfCurrentPosition(IGM.ProtocolRequirementStructTy));
}
if (entry.isAssociatedConformance()) {
// Define the associated conformance descriptor to point to the
// current position in the protocol descriptor.
AssociatedConformance conformance(
Proto,
entry.getAssociatedConformancePath(),
entry.getAssociatedConformanceRequirement());
IGM.defineAssociatedConformanceDescriptor(
conformance,
B.getAddrOfCurrentPosition(IGM.ProtocolRequirementStructTy));
}
if (entry.isBase()) {
// Define a base conformance descriptor, which is just an associated
// conformance descriptor for a base protocol.
BaseConformance conformance(Proto, entry.getBase());
IGM.defineBaseConformanceDescriptor(
conformance,
B.getAddrOfCurrentPosition(IGM.ProtocolRequirementStructTy));
}
auto reqt = B.beginStruct(IGM.ProtocolRequirementStructTy);
auto info = getRequirementInfo(entry);
// Flags.
reqt.addInt32(info.Flags.getIntValue());
// Default implementation.
reqt.addRelativeAddressOrNull(info.DefaultImpl);
reqt.finishAndAddTo(B);
}
}
llvm::Constant *findDefaultWitness(SILDeclRef func) {
if (!DefaultWitnesses) return nullptr;
for (auto &entry : DefaultWitnesses->getEntries()) {
if (!entry.isValid() || entry.getKind() != SILWitnessTable::Method ||
entry.getMethodWitness().Requirement != func)
continue;
return IGM.getAddrOfSILFunction(entry.getMethodWitness().Witness,
NotForDefinition);
}
return nullptr;
}
llvm::Constant *findDefaultTypeWitness(AssociatedTypeDecl *assocType) {
if (!DefaultWitnesses) return nullptr;
for (auto &entry : DefaultWitnesses->getEntries()) {
if (!entry.isValid() ||
entry.getKind() != SILWitnessTable::AssociatedType ||
entry.getAssociatedTypeWitness().Requirement != assocType)
continue;
auto witness =
entry.getAssociatedTypeWitness().Witness->mapTypeOutOfContext();
return IGM.getAssociatedTypeWitness(witness,
/*inProtocolContext=*/true);
}
return nullptr;
}
llvm::Constant *findDefaultAssociatedConformanceWitness(
CanType association,
ProtocolDecl *requirement) {
if (!DefaultWitnesses) return nullptr;
for (auto &entry : DefaultWitnesses->getEntries()) {
if (!entry.isValid() ||
entry.getKind() != SILWitnessTable::AssociatedTypeProtocol ||
entry.getAssociatedTypeProtocolWitness().Protocol != requirement ||
entry.getAssociatedTypeProtocolWitness().Requirement != association)
continue;
auto witness = entry.getAssociatedTypeProtocolWitness().Witness;
AssociatedConformance conformance(Proto, association, requirement);
defineDefaultAssociatedConformanceAccessFunction(conformance, witness);
return IGM.getMangledAssociatedConformance(nullptr, conformance);
}
return nullptr;
}
void defineDefaultAssociatedConformanceAccessFunction(
AssociatedConformance requirement,
ProtocolConformanceRef conformance) {
auto accessor =
IGM.getAddrOfDefaultAssociatedConformanceAccessor(requirement);
IRGenFunction IGF(IGM, accessor);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, accessor);
Explosion parameters = IGF.collectParameters();
llvm::Value *associatedTypeMetadata = parameters.claimNext();
llvm::Value *self = parameters.claimNext();
llvm::Value *wtable = parameters.claimNext();
bool hasArchetype =
!conformance.isConcrete() ||
conformance.getConcrete()->getType()->hasArchetype();
if (hasArchetype) {
// Bind local Self type data from the metadata argument.
auto selfInContext = Proto->getSelfTypeInContext()->getCanonicalType();
IGF.bindLocalTypeDataFromTypeMetadata(selfInContext, IsExact, self,
MetadataState::Abstract);
IGF.setUnscopedLocalTypeData(
selfInContext,
LocalTypeDataKind::forAbstractProtocolWitnessTable(Proto),
wtable);
// Bind the associated type metadata.
IGF.bindLocalTypeDataFromTypeMetadata(requirement.getAssociation(),
IsExact,
associatedTypeMetadata,
MetadataState::Abstract);
}
// For a concrete witness table, call it.
ProtocolDecl *associatedProtocol = requirement.getAssociatedRequirement();
if (conformance.isConcrete()) {
auto conformanceI = &IGM.getConformanceInfo(associatedProtocol,
conformance.getConcrete());
auto returnValue = conformanceI->getTable(IGF, &associatedTypeMetadata);
IGF.Builder.CreateRet(returnValue);
return;
}
// For an abstract table, emit a reference to the witness table.
CanType associatedTypeInContext
= Proto->mapTypeIntoContext(requirement.getAssociation())
->getCanonicalType();
auto returnValue =
emitArchetypeWitnessTableRef(
IGF,
cast<ArchetypeType>(associatedTypeInContext),
associatedProtocol);
IGF.Builder.CreateRet(returnValue);
return;
}
void addAssociatedTypeNames() {
std::string AssociatedTypeNames;
auto &pi = IGM.getProtocolInfo(Proto,
ProtocolInfoKind::RequirementSignature);
for (auto &entry : pi.getWitnessEntries()) {
// Add the associated type name to the list.
if (entry.isAssociatedType()) {
if (!AssociatedTypeNames.empty())
AssociatedTypeNames += ' ';
AssociatedTypeNames += entry.getAssociatedType()->getName().str();
}
}
llvm::Constant *global = nullptr;
if (!AssociatedTypeNames.empty()) {
global = IGM.getAddrOfGlobalString(AssociatedTypeNames,
/*willBeRelativelyAddressed=*/true);
}
B.addRelativeAddressOrNull(global);
}
};
template<class Impl, class DeclType>
class TypeContextDescriptorBuilderBase
: public ContextDescriptorBuilderBase<Impl> {
using super = ContextDescriptorBuilderBase<Impl>;
protected:
DeclType *Type;
RequireMetadata_t HasMetadata;
TypeContextDescriptorFlags::MetadataInitializationKind
MetadataInitialization;
StringRef UserFacingName;
Optional<TypeImportInfo<std::string>> ImportInfo;
using super::IGM;
using super::B;
using super::asImpl;
public:
using super::addGenericSignature;
TypeContextDescriptorBuilderBase(IRGenModule &IGM, DeclType *Type,
RequireMetadata_t requireMetadata)
: super(IGM), Type(Type),
HasMetadata(requireMetadata),
MetadataInitialization(computeMetadataInitialization()) {
}
void layout() {
asImpl().computeIdentity();
super::layout();
asImpl().addName();
asImpl().addAccessFunction();
asImpl().addReflectionFieldDescriptor();
asImpl().addLayoutInfo();
asImpl().addGenericSignature();
asImpl().maybeAddResilientSuperclass();
asImpl().maybeAddMetadataInitialization();
}
/// Fill out all the aspects of the type identity.
void computeIdentity() {
// Remember the user-facing name.
UserFacingName = Type->getName().str();
// For related entities, set the original type name as the ABI name
// and remember the related entity tag.
StringRef abiName;
if (auto *synthesizedTypeAttr =
Type->getAttrs()
.template getAttribute<ClangImporterSynthesizedTypeAttr>()) {
abiName = synthesizedTypeAttr->originalTypeName;
getMutableImportInfo().RelatedEntityName =
synthesizedTypeAttr->getManglingName();
// Otherwise, if this was imported from a Clang declaration, use that
// declaration's name as the ABI name.
} else if (auto clangDecl =
Mangle::ASTMangler::getClangDeclForMangling(Type)) {
abiName = clangDecl->getName();
// Typedefs and compatibility aliases that have been promoted to
// their own nominal types need to be marked specially.
if (isa<clang::TypedefNameDecl>(clangDecl) ||
isa<clang::ObjCCompatibleAliasDecl>(clangDecl)) {
getMutableImportInfo().SymbolNamespace =
TypeImportSymbolNamespace::CTypedef;
}
}
// If the ABI name differs from the user-facing name, add it as
// an override.
if (!abiName.empty() && abiName != UserFacingName) {
getMutableImportInfo().ABIName = abiName;
}
}
/// Get the mutable import info. Note that calling this method itself
/// changes the code to cause it to be used, so don't set it unless
/// you're about to write something into it.
TypeImportInfo<std::string> &getMutableImportInfo() {
if (!ImportInfo)
ImportInfo.emplace();
return *ImportInfo;
}
void addName() {
SmallString<32> name;
name += UserFacingName;
// Collect the import info if present.
if (ImportInfo) {
name += '\0';
ImportInfo->appendTo(name);
// getAddrOfGlobalString will add its own null terminator, so pop
// off the second one.
assert(name.back() == '\0');
name.pop_back();
assert(name.back() == '\0');
}
auto nameStr = IGM.getAddrOfGlobalString(name,
/*willBeRelativelyAddressed*/ true);
B.addRelativeAddress(nameStr);
}
void addAccessFunction() {
llvm::Constant *accessor;
// Don't include an access function if we're emitting the context
// descriptor without metadata.
if (!HasMetadata) {
accessor = nullptr;
// If it's a generic type, use the generic access function.
// This has a different prototype from an ordinary function, but
// the runtime knows to check for that.
} else if (Type->isGenericContext()) {
accessor = getGenericTypeMetadataAccessFunction(IGM, Type,
NotForDefinition);
// Otherwise, use the ordinary access function, which we'll define
// when we emit the metadata.
} else {
CanType type = Type->getDeclaredType()->getCanonicalType();
accessor = getOtherwiseDefinedTypeMetadataAccessFunction(IGM, type);
}
B.addRelativeAddressOrNull(accessor);
}
ConstantReference getParent() {
return IGM.getAddrOfParentContextDescriptor(
Type, /*fromAnonymousContext=*/false);
}
GenericSignature *getGenericSignature() {
return Type->getGenericSignature();
}
/// Fill in the fields of a TypeGenericContextDescriptorHeader.
void addGenericParametersHeader() {
asImpl().addMetadataInstantiationCache();
asImpl().addMetadataInstantiationPattern();
super::addGenericParametersHeader();
}
void addMetadataInstantiationPattern() {
if (!HasMetadata) {
B.addInt32(0);
return;
}
auto pattern = IGM.getAddrOfTypeMetadataPattern(Type);
B.addRelativeAddress(pattern);
}
void addMetadataInstantiationCache() {
if (!HasMetadata) {
B.addInt32(0);
return;
}
auto cache =
IGM.getAddrOfTypeMetadataInstantiationCache(Type, NotForDefinition);
B.addRelativeAddress(cache);
}
bool isUniqueDescriptor() {
return !isa<ClangModuleUnit>(Type->getModuleScopeContext());
}
llvm::Constant *emit() {
asImpl().layout();
auto addr = IGM.getAddrOfTypeContextDescriptor(Type, HasMetadata,
B.finishAndCreateFuture());
auto var = cast<llvm::GlobalVariable>(addr);
var->setConstant(true);
IGM.setTrueConstGlobal(var);
return var;
}
void setCommonFlags(TypeContextDescriptorFlags &flags) {
setClangImportedFlags(flags);
setMetadataInitializationKind(flags);
}
void setClangImportedFlags(TypeContextDescriptorFlags &flags) {
if (ImportInfo) {
flags.setHasImportInfo(true);
}
}
TypeContextDescriptorFlags::MetadataInitializationKind
computeMetadataInitialization() {
// Not if we don't have metadata.
if (!HasMetadata)
return TypeContextDescriptorFlags::NoMetadataInitialization;
// Generic types use their own system.
if (Type->isGenericContext())
return TypeContextDescriptorFlags::NoMetadataInitialization;
// Check for foreign metadata.
if (requiresForeignTypeMetadata(Type))
return TypeContextDescriptorFlags::ForeignMetadataInitialization;
// The only other option is singleton initialization.
if (needsSingletonMetadataInitialization(IGM, Type))
return TypeContextDescriptorFlags::SingletonMetadataInitialization;
return TypeContextDescriptorFlags::NoMetadataInitialization;
}
void setMetadataInitializationKind(TypeContextDescriptorFlags &flags) {
flags.setMetadataInitialization(MetadataInitialization);
}
void maybeAddMetadataInitialization() {
switch (MetadataInitialization) {
case TypeContextDescriptorFlags::NoMetadataInitialization:
return;
case TypeContextDescriptorFlags::ForeignMetadataInitialization:
addForeignMetadataInitialization();
return;
case TypeContextDescriptorFlags::SingletonMetadataInitialization:
addSingletonMetadataInitialization();
return;
}
llvm_unreachable("bad kind");
}
/// Add a ForeignMetadataInitialization structure to the descriptor.
void addForeignMetadataInitialization() {
llvm::Constant *completionFunction = nullptr;
if (asImpl().needsForeignMetadataCompletionFunction()) {
completionFunction =
IGM.getAddrOfTypeMetadataCompletionFunction(Type, NotForDefinition);
}
B.addRelativeAddressOrNull(completionFunction);
}
bool needsForeignMetadataCompletionFunction() {
return ::needsForeignMetadataCompletionFunction(IGM, Type);
}
/// Add an SingletonMetadataInitialization structure to the descriptor.
void addSingletonMetadataInitialization() {
// Relative pointer to the initialization cache.
// Note that we trigger the definition of it when emitting the
// completion function.
auto cache = IGM.getAddrOfTypeMetadataSingletonInitializationCache(Type,
NotForDefinition);
B.addRelativeAddress(cache);
asImpl().addIncompleteMetadataOrRelocationFunction();
// Completion function.
auto completionFunction =
IGM.getAddrOfTypeMetadataCompletionFunction(Type, NotForDefinition);
B.addRelativeAddress(completionFunction);
}
void addIncompleteMetadata() {
// Relative pointer to the metadata.
auto type = Type->getDeclaredTypeInContext()->getCanonicalType();
auto metadata = IGM.getAddrOfTypeMetadata(type);
B.addRelativeAddress(metadata);
}
/// Customization point for ClassContextDescriptorBuilder.
void addIncompleteMetadataOrRelocationFunction() {
addIncompleteMetadata();
}
// Subclasses should provide:
// ContextDescriptorKind getContextKind();
// void addLayoutInfo();
// void addReflectionFieldDescriptor();
};
class StructContextDescriptorBuilder
: public TypeContextDescriptorBuilderBase<StructContextDescriptorBuilder,
StructDecl>
{
using super = TypeContextDescriptorBuilderBase;
StructDecl *getType() {
return cast<StructDecl>(Type);
}
Size FieldVectorOffset;
public:
StructContextDescriptorBuilder(IRGenModule &IGM, StructDecl *Type,
RequireMetadata_t requireMetadata)
: super(IGM, Type, requireMetadata)
{
auto &layout = IGM.getMetadataLayout(getType());
FieldVectorOffset = layout.getFieldOffsetVectorOffset().getStatic();
}
ContextDescriptorKind getContextKind() {
return ContextDescriptorKind::Struct;
}
void addLayoutInfo() {
auto properties = getType()->getStoredProperties();
// uint32_t NumFields;
B.addInt32(properties.size());
// uint32_t FieldOffsetVectorOffset;
B.addInt32(FieldVectorOffset / IGM.getPointerSize());
}
uint16_t getKindSpecificFlags() {
TypeContextDescriptorFlags flags;
setCommonFlags(flags);
return flags.getOpaqueValue();
}
void maybeAddResilientSuperclass() { }
void addReflectionFieldDescriptor() {
if (!IGM.IRGen.Opts.EnableReflectionMetadata) {
B.addInt32(0);
return;
}
IGM.IRGen.noteUseOfFieldDescriptor(getType());
B.addRelativeAddress(IGM.getAddrOfReflectionFieldDescriptor(
getType()->getDeclaredType()->getCanonicalType()));
}
};
class EnumContextDescriptorBuilder
: public TypeContextDescriptorBuilderBase<EnumContextDescriptorBuilder,
EnumDecl>
{
using super = TypeContextDescriptorBuilderBase;
EnumDecl *getType() {
return cast<EnumDecl>(Type);
}
Size PayloadSizeOffset;
const EnumImplStrategy &Strategy;
public:
EnumContextDescriptorBuilder(IRGenModule &IGM, EnumDecl *Type,
RequireMetadata_t requireMetadata)
: super(IGM, Type, requireMetadata),
Strategy(getEnumImplStrategy(IGM,
getType()->getDeclaredTypeInContext()->getCanonicalType()))
{
auto &layout = IGM.getMetadataLayout(getType());
if (layout.hasPayloadSizeOffset())
PayloadSizeOffset = layout.getPayloadSizeOffset().getStatic();
}
ContextDescriptorKind getContextKind() {
return ContextDescriptorKind::Enum;
}
void addLayoutInfo() {
// # payload cases in the low 24 bits, payload size offset in the high 8.
unsigned numPayloads = Strategy.getElementsWithPayload().size();
assert(numPayloads < (1<<24) && "too many payload elements for runtime");
assert(PayloadSizeOffset % IGM.getPointerAlignment() == Size(0)
&& "payload size not word-aligned");
unsigned PayloadSizeOffsetInWords
= PayloadSizeOffset / IGM.getPointerSize();
assert(PayloadSizeOffsetInWords < 0x100 &&
"payload size offset too far from address point for runtime");
// uint32_t NumPayloadCasesAndPayloadSizeOffset;
B.addInt32(numPayloads | (PayloadSizeOffsetInWords << 24));
// uint32_t NumEmptyCases;
B.addInt32(Strategy.getElementsWithNoPayload().size());
}
uint16_t getKindSpecificFlags() {
TypeContextDescriptorFlags flags;
setCommonFlags(flags);
return flags.getOpaqueValue();
}
void maybeAddResilientSuperclass() { }
void addReflectionFieldDescriptor() {
if (!IGM.IRGen.Opts.EnableReflectionMetadata) {
B.addInt32(0);
return;
}
// Force the emission of the field descriptor or fixed descriptor.
IGM.IRGen.noteUseOfFieldDescriptor(getType());
// Some enum layout strategies (viz. C compatible layout) aren't
// supported by reflection.
if (!Strategy.isReflectable()) {
B.addInt32(0);
return;
}
B.addRelativeAddress(IGM.getAddrOfReflectionFieldDescriptor(
getType()->getDeclaredType()->getCanonicalType()));
}
};
class ClassContextDescriptorBuilder
: public TypeContextDescriptorBuilderBase<ClassContextDescriptorBuilder,
ClassDecl>,
public SILVTableVisitor<ClassContextDescriptorBuilder>
{
using super = TypeContextDescriptorBuilderBase;
ClassDecl *getType() {
return cast<ClassDecl>(Type);
}
// Non-null unless the type is foreign.
ClassMetadataLayout *MetadataLayout = nullptr;
Optional<TypeEntityReference> ResilientSuperClassRef;
SILVTable *VTable;
bool Resilient;
SmallVector<SILDeclRef, 8> VTableEntries;
SmallVector<std::pair<SILDeclRef, SILDeclRef>, 8> OverrideTableEntries;
public:
ClassContextDescriptorBuilder(IRGenModule &IGM, ClassDecl *Type,
RequireMetadata_t requireMetadata)
: super(IGM, Type, requireMetadata),
VTable(IGM.getSILModule().lookUpVTable(getType())),
Resilient(IGM.hasResilientMetadata(Type, ResilienceExpansion::Minimal)) {
if (getType()->isForeign()) return;
MetadataLayout = &IGM.getClassMetadataLayout(Type);
if (auto superclassDecl = getType()->getSuperclassDecl()) {
if (MetadataLayout && MetadataLayout->hasResilientSuperclass())
ResilientSuperClassRef = IGM.getTypeEntityReference(superclassDecl);
}
addVTableEntries(getType());
}
void addMethod(SILDeclRef fn) {
VTableEntries.push_back(fn);
}
void addMethodOverride(SILDeclRef baseRef, SILDeclRef declRef) {
OverrideTableEntries.emplace_back(baseRef, declRef);
}
void layout() {
super::layout();
addVTable();
addOverrideTable();
addObjCResilientClassStubInfo();
}
void addIncompleteMetadataOrRelocationFunction() {
if (MetadataLayout == nullptr ||
!MetadataLayout->hasResilientSuperclass()) {
addIncompleteMetadata();
return;
}
auto *pattern = IGM.getAddrOfTypeMetadataPattern(Type);
B.addRelativeAddress(pattern);
}
ContextDescriptorKind getContextKind() {
return ContextDescriptorKind::Class;
}
uint16_t getKindSpecificFlags() {
TypeContextDescriptorFlags flags;
setCommonFlags(flags);
if (!getType()->isForeign()) {
if (MetadataLayout->areImmediateMembersNegative())
flags.class_setAreImmediateMembersNegative(true);
if (!VTableEntries.empty())
flags.class_setHasVTable(true);
if (!OverrideTableEntries.empty())
flags.class_setHasOverrideTable(true);
if (MetadataLayout->hasResilientSuperclass())
flags.class_setHasResilientSuperclass(true);
}
if (ResilientSuperClassRef) {
flags.class_setResilientSuperclassReferenceKind(
ResilientSuperClassRef->getKind());
}
return flags.getOpaqueValue();
}
void maybeAddResilientSuperclass() {
// RelativeDirectPointer<const void, /*nullable*/ true> SuperClass;
if (ResilientSuperClassRef) {
B.addRelativeAddress(ResilientSuperClassRef->getValue());
}
}
void addReflectionFieldDescriptor() {
// Classes are always reflectable, unless reflection is disabled or this
// is a foreign class.
if (!IGM.IRGen.Opts.EnableReflectionMetadata ||
getType()->isForeign()) {
B.addInt32(0);
return;
}
B.addRelativeAddress(IGM.getAddrOfReflectionFieldDescriptor(
getType()->getDeclaredType()->getCanonicalType()));
}
Size getFieldVectorOffset() {
if (!MetadataLayout) return Size(0);
return (MetadataLayout->hasResilientSuperclass()
? MetadataLayout->getRelativeFieldOffsetVectorOffset()
: MetadataLayout->getStaticFieldOffsetVectorOffset());
}
void addVTable() {
if (VTableEntries.empty())
return;
// Only emit a method lookup function if the class is resilient
// and has a non-empty vtable.
if (IGM.hasResilientMetadata(getType(), ResilienceExpansion::Minimal))
IGM.emitMethodLookupFunction(getType());
auto offset = MetadataLayout->hasResilientSuperclass()
? MetadataLayout->getRelativeVTableOffset()
: MetadataLayout->getStaticVTableOffset();
B.addInt32(offset / IGM.getPointerSize());
B.addInt32(VTableEntries.size());
for (auto fn : VTableEntries)
emitMethodDescriptor(fn);
}
void emitMethodDescriptor(SILDeclRef fn) {
// Define the method descriptor to point to the current position in the
// nominal type descriptor.
IGM.defineMethodDescriptor(fn, Type,
B.getAddrOfCurrentPosition(IGM.MethodDescriptorStructTy));
// Actually build the descriptor.
auto *func = cast<AbstractFunctionDecl>(fn.getDecl());
auto descriptor = B.beginStruct(IGM.MethodDescriptorStructTy);
// Classify the method.
using Flags = MethodDescriptorFlags;
auto flags = getMethodDescriptorFlags<Flags>(func);
// Remember if the declaration was dynamic.
if (func->isObjCDynamic())
flags = flags.withIsDynamic(true);
// TODO: final? open?
descriptor.addInt(IGM.Int32Ty, flags.getIntValue());
if (auto entry = VTable->getEntry(IGM.getSILModule(), fn)) {
assert(entry->TheKind == SILVTable::Entry::Kind::Normal);
auto *implFn = IGM.getAddrOfSILFunction(entry->Implementation,
NotForDefinition);
descriptor.addRelativeAddress(implFn);
} else {
// The method is removed by dead method elimination.
// It should be never called. We add a pointer to an error function.
descriptor.addRelativeAddressOrNull(nullptr);
}
descriptor.finishAndAddTo(B);
// Emit method dispatch thunk if the class is resilient.
if (Resilient &&
func->getEffectiveAccess() >= AccessLevel::Public) {
IGM.emitDispatchThunk(fn);
}
}
void addOverrideTable() {
if (OverrideTableEntries.empty())
return;
B.addInt32(OverrideTableEntries.size());
for (auto pair : OverrideTableEntries)
emitMethodOverrideDescriptor(pair.first, pair.second);
}
void emitMethodOverrideDescriptor(SILDeclRef baseRef, SILDeclRef declRef) {
auto descriptor = B.beginStruct(IGM.MethodOverrideDescriptorStructTy);
// The class containing the base method.
auto *baseClass = cast<ClassDecl>(baseRef.getDecl()->getDeclContext());
IGM.IRGen.noteUseOfTypeContextDescriptor(baseClass, DontRequireMetadata);
auto baseClassEntity = LinkEntity::forNominalTypeDescriptor(baseClass);
auto baseClassDescriptor =
IGM.getAddrOfLLVMVariableOrGOTEquivalent(baseClassEntity);
descriptor.addRelativeAddress(baseClassDescriptor);
// The base method.
auto baseMethodEntity = LinkEntity::forMethodDescriptor(baseRef);
auto baseMethodDescriptor =
IGM.getAddrOfLLVMVariableOrGOTEquivalent(baseMethodEntity);
descriptor.addRelativeAddress(baseMethodDescriptor);
// The implementation of the override.
if (auto entry = VTable->getEntry(IGM.getSILModule(), baseRef)) {
assert(entry->TheKind == SILVTable::Entry::Kind::Override);
auto *implFn = IGM.getAddrOfSILFunction(entry->Implementation,
NotForDefinition);
descriptor.addRelativeAddress(implFn);
} else {
// The method is removed by dead method elimination.
// It should be never called. We add a pointer to an error function.
descriptor.addRelativeAddressOrNull(nullptr);
}
descriptor.finishAndAddTo(B);
}
void addPlaceholder(MissingMemberDecl *MMD) {
llvm_unreachable("cannot generate metadata with placeholders in it");
}
void addLayoutInfo() {
// TargetRelativeDirectPointer<Runtime, const char> SuperclassType;
if (auto superclassType = getType()->getSuperclass()) {
GenericSignature *genericSig = getType()->getGenericSignature();
B.addRelativeAddress(IGM.getTypeRef(superclassType->getCanonicalType(),
genericSig,
MangledTypeRefRole::Metadata)
.first);
} else {
B.addInt32(0);
}
auto properties = getType()->getStoredProperties();
// union {
// uint32_t MetadataNegativeSizeInWords;
// RelativeDirectPointer<StoredClassMetadataBounds>
// ResilientMetadataBounds;
// };
if (!MetadataLayout) {
// FIXME: do something meaningful for foreign classes?
B.addInt32(0);
} else if (!MetadataLayout->hasResilientSuperclass()) {
B.addInt32(MetadataLayout->getSize().AddressPoint
/ IGM.getPointerSize());
} else {
B.addRelativeAddress(
IGM.getAddrOfClassMetadataBounds(getType(), NotForDefinition));
}
// union {
// uint32_t MetadataPositiveSizeInWords;
// ExtraClassContextFlags ExtraClassFlags;
// };
if (!MetadataLayout) {
// FIXME: do something meaningful for foreign classes?
B.addInt32(0);
} else if (!MetadataLayout->hasResilientSuperclass()) {
B.addInt32(MetadataLayout->getSize().getOffsetToEnd()
/ IGM.getPointerSize());
} else {
ExtraClassDescriptorFlags flags;
if (hasObjCResilientClassStub(IGM, getType()))
flags.setObjCResilientClassStub(true);
B.addInt32(flags.getOpaqueValue());
}
// uint32_t NumImmediateMembers;
auto numImmediateMembers =
(MetadataLayout ? MetadataLayout->getNumImmediateMembers() : 0);
B.addInt32(numImmediateMembers);
// uint32_t NumFields;
B.addInt32(properties.size());
// uint32_t FieldOffsetVectorOffset;
B.addInt32(getFieldVectorOffset() / IGM.getPointerSize());
}
void addObjCResilientClassStubInfo() {
if (IGM.getClassMetadataStrategy(getType()) !=
ClassMetadataStrategy::Resilient)
return;
if (!hasObjCResilientClassStub(IGM, getType()))
return;
B.addRelativeAddress(
IGM.getAddrOfObjCResilientClassStub(
getType(), NotForDefinition,
TypeMetadataAddress::AddressPoint));
}
};
class OpaqueTypeDescriptorBuilder
: public ContextDescriptorBuilderBase<OpaqueTypeDescriptorBuilder>
{
using super = ContextDescriptorBuilderBase;
OpaqueTypeDecl *O;
public:
OpaqueTypeDescriptorBuilder(IRGenModule &IGM, OpaqueTypeDecl *O)
: super(IGM), O(O)
{}
void layout() {
super::layout();
addGenericSignature();
addUnderlyingTypeAndConformances();
}
void addUnderlyingTypeAndConformances() {
auto underlyingType = Type(O->getUnderlyingInterfaceType())
.subst(*O->getUnderlyingTypeSubstitutions())
->getCanonicalType(O->getOpaqueInterfaceGenericSignature());
B.addRelativeAddress(IGM.getTypeRef(underlyingType,
MangledTypeRefRole::Metadata).first);
auto opaqueType = O->getDeclaredInterfaceType()
->castTo<OpaqueTypeArchetypeType>();
for (auto proto : opaqueType->getConformsTo()) {
auto conformance = ProtocolConformanceRef(proto);
auto underlyingConformance = conformance
.subst(O->getUnderlyingInterfaceType(),
*O->getUnderlyingTypeSubstitutions());
auto witnessTableRef = IGM.emitWitnessTableRefString(
underlyingType, underlyingConformance,
O->getGenericSignature(),
/*setLowBit*/ false);
B.addRelativeAddress(witnessTableRef);
}
}
bool isUniqueDescriptor() {
switch (LinkEntity::forOpaqueTypeDescriptor(O)
.getLinkage(NotForDefinition)) {
case SILLinkage::Public:
case SILLinkage::PublicExternal:
case SILLinkage::Hidden:
case SILLinkage::HiddenExternal:
case SILLinkage::Private:
case SILLinkage::PrivateExternal:
return true;
case SILLinkage::Shared:
case SILLinkage::SharedExternal:
case SILLinkage::PublicNonABI:
return false;
}
llvm_unreachable("covered switch");
}
GenericSignature *getGenericSignature() {
return O->getOpaqueInterfaceGenericSignature();
}
ConstantReference getParent() {
// VarDecls aren't normally contexts, but we still want to mangle
// an anonymous context for one.
if (IGM.IRGen.Opts.EnableAnonymousContextMangledNames) {
if (auto namingVar = dyn_cast<VarDecl>(O->getNamingDecl())) {
return ConstantReference(
IGM.getAddrOfAnonymousContextDescriptor(namingVar),
ConstantReference::Direct);
}
}
DeclContext *parent = O->getNamingDecl()->getInnermostDeclContext();
// If we have debug mangled names enabled for anonymous contexts, nest
// the opaque type descriptor inside an anonymous context for the
// defining function. This will let type reconstruction in the debugger
// match the opaque context back into the AST.
//
// Otherwise, we can use the module context for nongeneric contexts.
if (!IGM.IRGen.Opts.EnableAnonymousContextMangledNames
&& !parent->isGenericContext()) {
parent = parent->getParentModule();
}
return IGM.getAddrOfContextDescriptorForParent(parent, parent,
/*fromAnonymous*/ false);
}
ContextDescriptorKind getContextKind() {
return ContextDescriptorKind::OpaqueType;
}
void emit() {
asImpl().layout();
auto addr = IGM.getAddrOfOpaqueTypeDescriptor(O,
B.finishAndCreateFuture());
auto var = cast<llvm::GlobalVariable>(addr);
var->setConstant(true);
IGM.setTrueConstGlobal(var);
IGM.emitOpaqueTypeDescriptorAccessor(O);
}
uint16_t getKindSpecificFlags() {
// Store the size of the type and conformances vector in the flags.
auto opaqueType = O->getDeclaredInterfaceType()
->castTo<OpaqueTypeArchetypeType>();
return 1 + opaqueType->getConformsTo().size();
}
};
} // end anonymous namespace
static void eraseExistingTypeContextDescriptor(IRGenModule &IGM,
NominalTypeDecl *type) {
// We may have emitted a partial type context descriptor with some empty
// fields, and then later discovered we're emitting complete metadata.
// Remove existing definitions of the type context so that we can regenerate
// a complete descriptor.
auto entity = IGM.getAddrOfTypeContextDescriptor(type, DontRequireMetadata);
entity = entity->stripPointerCasts();
auto existingContext = dyn_cast<llvm::GlobalVariable>(entity);
if (existingContext && !existingContext->isDeclaration()) {
existingContext->setInitializer(nullptr);
}
}
void irgen::emitLazyTypeContextDescriptor(IRGenModule &IGM,
NominalTypeDecl *type,
RequireMetadata_t requireMetadata) {
eraseExistingTypeContextDescriptor(IGM, type);
if (auto sd = dyn_cast<StructDecl>(type)) {
StructContextDescriptorBuilder(IGM, sd, requireMetadata).emit();
} else if (auto ed = dyn_cast<EnumDecl>(type)) {
EnumContextDescriptorBuilder(IGM, ed, requireMetadata).emit();
} else if (auto cd = dyn_cast<ClassDecl>(type)) {
ClassContextDescriptorBuilder(IGM, cd, requireMetadata).emit();
} else {
llvm_unreachable("type does not have a context descriptor");
}
}
void irgen::emitLazyTypeMetadata(IRGenModule &IGM, NominalTypeDecl *type) {
eraseExistingTypeContextDescriptor(IGM, type);
if (requiresForeignTypeMetadata(type)) {
emitForeignTypeMetadata(IGM, type);
} else if (auto sd = dyn_cast<StructDecl>(type)) {
emitStructMetadata(IGM, sd);
} else if (auto ed = dyn_cast<EnumDecl>(type)) {
emitEnumMetadata(IGM, ed);
} else if (auto pd = dyn_cast<ProtocolDecl>(type)) {
IGM.emitProtocolDecl(pd);
} else {
llvm_unreachable("should not have enqueued a class decl here!");
}
}
llvm::Constant *
IRGenModule::getAddrOfSharedContextDescriptor(LinkEntity entity,
ConstantInit definition,
llvm::function_ref<void()> emit) {
if (!definition) {
// Generate the definition if it hasn't been generated yet.
auto existing = GlobalVars.find(entity);
if (existing == GlobalVars.end() ||
!existing->second
|| cast<llvm::GlobalValue>(existing->second)->isDeclaration()) {
// In some cases we have multiple declarations in the AST that end up
// with the same context mangling (a clang module and its overlay,
// equivalent extensions, etc.). These can share a context descriptor
// at runtime.
auto mangledName = entity.mangleAsString();
if (auto otherDefinition = Module.getGlobalVariable(mangledName)) {
GlobalVars.insert({entity, otherDefinition});
return otherDefinition;
}
// Otherwise, emit the descriptor.
emit();
}
}
return getAddrOfLLVMVariable(entity,
definition,
DebugTypeInfo());
}
llvm::Constant *
IRGenModule::getAddrOfModuleContextDescriptor(ModuleDecl *D,
ConstantInit definition) {
auto entity = LinkEntity::forModuleDescriptor(D);
return getAddrOfSharedContextDescriptor(entity, definition,
[&]{ ModuleContextDescriptorBuilder(*this, D).emit(); });
}
llvm::Constant *
IRGenModule::getAddrOfObjCModuleContextDescriptor() {
if (!ObjCModule)
ObjCModule = ModuleDecl::create(
Context.getIdentifier(MANGLING_MODULE_OBJC),
Context);
return getAddrOfModuleContextDescriptor(ObjCModule);
}
llvm::Constant *
IRGenModule::getAddrOfClangImporterModuleContextDescriptor() {
if (!ClangImporterModule)
ClangImporterModule = ModuleDecl::create(
Context.getIdentifier(MANGLING_MODULE_CLANG_IMPORTER),
Context);
return getAddrOfModuleContextDescriptor(ClangImporterModule);
}
llvm::Constant *
IRGenModule::getAddrOfExtensionContextDescriptor(ExtensionDecl *ED,
ConstantInit definition) {
auto entity = LinkEntity::forExtensionDescriptor(ED);
return getAddrOfSharedContextDescriptor(entity, definition,
[&]{ ExtensionContextDescriptorBuilder(*this, ED).emit(); });
}
llvm::Constant *
IRGenModule::getAddrOfAnonymousContextDescriptor(
PointerUnion<DeclContext *, VarDecl *> DC,
ConstantInit definition) {
auto entity = LinkEntity::forAnonymousDescriptor(DC);
return getAddrOfSharedContextDescriptor(entity, definition,
[&]{ AnonymousContextDescriptorBuilder(*this, DC).emit(); });
}
static void emitInitializeFieldOffsetVector(IRGenFunction &IGF,
SILType T,
llvm::Value *metadata,
bool isVWTMutable,
MetadataDependencyCollector *collector) {
auto &IGM = IGF.IGM;
auto *target = T.getNominalOrBoundGenericNominal();
llvm::Value *fieldVector
= emitAddressOfFieldOffsetVector(IGF, metadata, target)
.getAddress();
// Collect the stored properties of the type.
llvm::SmallVector<VarDecl*, 4> storedProperties;
for (auto prop : target->getStoredProperties()) {
storedProperties.push_back(prop);
}
// Fill out an array with the field type metadata records.
Address fields = IGF.createAlloca(
llvm::ArrayType::get(IGM.Int8PtrPtrTy,
storedProperties.size()),
IGM.getPointerAlignment(), "classFields");
IGF.Builder.CreateLifetimeStart(fields,
IGM.getPointerSize() * storedProperties.size());
fields = IGF.Builder.CreateStructGEP(fields, 0, Size(0));
unsigned index = 0;
for (auto prop : storedProperties) {
auto propTy = T.getFieldType(prop, IGF.getSILModule());
llvm::Value *metadata = emitTypeLayoutRef(IGF, propTy, collector);
Address field = IGF.Builder.CreateConstArrayGEP(fields, index,
IGM.getPointerSize());
IGF.Builder.CreateStore(metadata, field);
++index;
}
// Ask the runtime to lay out the struct or class.
auto numFields = IGM.getSize(Size(storedProperties.size()));
if (auto *classDecl = dyn_cast<ClassDecl>(target)) {
// Compute class layout flags.
ClassLayoutFlags flags = ClassLayoutFlags::Swift5Algorithm;
switch (IGM.getClassMetadataStrategy(classDecl)) {
case ClassMetadataStrategy::Resilient:
break;
case ClassMetadataStrategy::Singleton:
case ClassMetadataStrategy::Update:
case ClassMetadataStrategy::FixedOrUpdate:
flags |= ClassLayoutFlags::HasStaticVTable;
break;
case ClassMetadataStrategy::Fixed:
llvm_unreachable("Emitting metadata init for fixed class metadata?");
}
llvm::Value *dependency;
switch (IGM.getClassMetadataStrategy(classDecl)) {
case ClassMetadataStrategy::Resilient:
case ClassMetadataStrategy::Singleton:
// Call swift_initClassMetadata().
dependency =
IGF.Builder.CreateCall(IGM.getInitClassMetadata2Fn(),
{metadata,
IGM.getSize(Size(uintptr_t(flags))),
numFields, fields.getAddress(), fieldVector});
break;
case ClassMetadataStrategy::Update:
case ClassMetadataStrategy::FixedOrUpdate:
assert(IGM.Context.LangOpts.EnableObjCInterop);
// Call swift_updateClassMetadata(). Note that the static metadata
// already references the superclass in this case, but we still want
// to ensure the superclass metadata is initialized first.
dependency =
IGF.Builder.CreateCall(IGM.getUpdateClassMetadata2Fn(),
{metadata,
IGM.getSize(Size(uintptr_t(flags))),
numFields, fields.getAddress(), fieldVector});
break;
case ClassMetadataStrategy::Fixed:
llvm_unreachable("Emitting metadata init for fixed class metadata?");
}
// Collect any possible dependency from initializing the class; generally
// this involves the superclass.
assert(collector);
collector->collect(IGF, dependency);
} else {
assert(isa<StructDecl>(target));
// Compute struct layout flags.
StructLayoutFlags flags = StructLayoutFlags::Swift5Algorithm;
if (isVWTMutable)
flags |= StructLayoutFlags::IsVWTMutable;
// Call swift_initStructMetadata().
IGF.Builder.CreateCall(IGM.getInitStructMetadataFn(),
{metadata, IGM.getSize(Size(uintptr_t(flags))),
numFields, fields.getAddress(), fieldVector});
}
IGF.Builder.CreateLifetimeEnd(fields,
IGM.getPointerSize() * storedProperties.size());
}
static void emitInitializeValueMetadata(IRGenFunction &IGF,
NominalTypeDecl *nominalDecl,
llvm::Value *metadata,
bool isVWTMutable,
MetadataDependencyCollector *collector) {
auto loweredTy =
IGF.IGM.getLoweredType(nominalDecl->getDeclaredTypeInContext());
if (isa<StructDecl>(nominalDecl)) {
auto &fixedTI = IGF.IGM.getTypeInfo(loweredTy);
if (isa<FixedTypeInfo>(fixedTI)) return;
emitInitializeFieldOffsetVector(IGF, loweredTy, metadata, isVWTMutable,
collector);
} else {
assert(isa<EnumDecl>(nominalDecl));
auto &strategy = getEnumImplStrategy(IGF.IGM, loweredTy);
strategy.initializeMetadata(IGF, metadata, isVWTMutable, loweredTy,
collector);
}
}
static void emitInitializeClassMetadata(IRGenFunction &IGF,
ClassDecl *classDecl,
const ClassLayout &fieldLayout,
llvm::Value *metadata,
MetadataDependencyCollector *collector) {
auto &IGM = IGF.IGM;
assert(IGM.getClassMetadataStrategy(classDecl)
!= ClassMetadataStrategy::Fixed);
auto loweredTy =
IGM.getLoweredType(classDecl->getDeclaredTypeInContext());
// Set the superclass, fill out the field offset vector, and copy vtable
// entries, generic requirements and field offsets from superclasses.
emitInitializeFieldOffsetVector(IGF, loweredTy,
metadata, /*VWT is mutable*/ false,
collector);
// Realizing the class with the ObjC runtime will copy back to the
// field offset globals for us; but if ObjC interop is disabled, we
// have to do that ourselves, assuming we didn't just emit them all
// correctly in the first place.
if (!IGM.ObjCInterop) {
for (auto prop : classDecl->getStoredProperties()) {
auto fieldInfo = fieldLayout.getFieldAccessAndElement(prop);
if (fieldInfo.first == FieldAccess::NonConstantDirect) {
Address offsetA = IGM.getAddrOfFieldOffset(prop, ForDefinition);
// We can't use emitClassFieldOffset() here because that creates
// an invariant load, which could be hoisted above the point
// where the metadata becomes fully initialized
auto slot =
emitAddressOfClassFieldOffset(IGF, metadata, classDecl, prop);
auto offsetVal = IGF.emitInvariantLoad(slot);
IGF.Builder.CreateStore(offsetVal, offsetA);
}
}
}
}
static MetadataKind getMetadataKind(NominalTypeDecl *nominalDecl) {
if (isa<StructDecl>(nominalDecl))
return MetadataKind::Struct;
assert(isa<EnumDecl>(nominalDecl));
return (nominalDecl->isOptionalDecl()
? MetadataKind::Optional
: MetadataKind::Enum);
}
/*****************************************************************************/
/** Metadata Emission ********************************************************/
/*****************************************************************************/
namespace {
/// An adapter class which turns a metadata layout class into a
/// generic metadata layout class.
template <class Impl, class DeclType>
class GenericMetadataBuilderBase {
protected:
IRGenModule &IGM;
DeclType *Target;
ConstantStructBuilder &B;
/// Set to true if the metadata record for the generic type has fields
/// outside of the generic parameter vector.
bool HasDependentMetadata = false;
/// Set to true if the value witness table for the generic type is dependent
/// on its generic parameters. Implies HasDependentMetadata.
bool HasDependentVWT = false;
GenericMetadataBuilderBase(IRGenModule &IGM, DeclType *Target,
ConstantStructBuilder &B)
: IGM(IGM), Target(Target), B(B) {}
/// Emit the instantiation cache variable for the template.
void emitInstantiationCache() {
auto cache = cast<llvm::GlobalVariable>(
IGM.getAddrOfTypeMetadataInstantiationCache(Target, ForDefinition));
auto init =
llvm::ConstantAggregateZero::get(cache->getValueType());
cache->setInitializer(init);
}
Impl &asImpl() { return *static_cast<Impl*>(this); }
/// Emit the create function for the template.
void emitInstantiationFunction() {
// using MetadataInstantiator =
// Metadata *(TypeContextDescriptor *type,
// const void * const *arguments,
// const GenericMetadataPattern *pattern);
llvm::Function *f =
IGM.getAddrOfTypeMetadataInstantiationFunction(Target, ForDefinition);
f->setAttributes(IGM.constructInitialAttributes());
f->setDoesNotThrow();
IGM.setHasFramePointer(f, false);
IRGenFunction IGF(IGM, f);
// Skip instrumentation when building for TSan to avoid false positives.
// The synchronization for this happens in the Runtime and we do not see it.
if (IGM.IRGen.Opts.Sanitizers & SanitizerKind::Thread)
f->removeFnAttr(llvm::Attribute::SanitizeThread);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, f);
Explosion params = IGF.collectParameters();
llvm::Value *descriptor = params.claimNext();
llvm::Value *args = params.claimNext();
llvm::Value *templatePointer = params.claimNext();
// Bind the generic arguments.
if (Target->isGenericContext()) {
Address argsArray(args, IGM.getPointerAlignment());
emitPolymorphicParametersFromArray(IGF, Target, argsArray,
MetadataState::Abstract);
}
// Allocate the metadata.
llvm::Value *metadata =
asImpl().emitAllocateMetadata(IGF, descriptor, args, templatePointer);
IGF.Builder.CreateRet(metadata);
}
void emitCompletionFunction() {
// using MetadataCompleter =
// MetadataDependency(Metadata *type,
// MetadataCompletionContext *context,
// const GenericMetadataPattern *pattern);
emitMetadataCompletionFunction(IGM, Target,
[&](IRGenFunction &IGF, llvm::Value *metadata,
MetadataDependencyCollector *collector) {
// Bind the generic arguments.
// FIXME: this will be problematic if we ever try to bind superclass
// types from type metadata!
assert(Target->isGenericContext());
auto type = Target->getDeclaredTypeInContext()->getCanonicalType();
IGF.bindLocalTypeDataFromTypeMetadata(type, IsExact, metadata,
MetadataState::Abstract);
// A dependent VWT means that we have dependent metadata.
if (HasDependentVWT)
HasDependentMetadata = true;
if (HasDependentMetadata)
asImpl().emitInitializeMetadata(IGF, metadata, false, collector);
});
}
/// The information necessary to fill in a GenericMetadataPartialPattern
/// structure.
struct PartialPattern {
llvm::Constant *Data;
Size DataOffset;
Size DataSize;
};
void addPartialPattern(PartialPattern pattern) {
// RelativeDirectPointer<void*> Pattern;
B.addRelativeAddress(pattern.Data);
// uint16_t OffsetInWords;
B.addInt16(IGM.getOffsetInWords(pattern.DataOffset));
// uint16_t SizeInWords;
B.addInt16(IGM.getOffsetInWords(pattern.DataSize));
}
public:
void createMetadataAccessFunction() {
(void) getGenericTypeMetadataAccessFunction(IGM, Target, ForDefinition);
}
void layout() {
asImpl().layoutHeader();
if (asImpl().hasExtraDataPattern()) {
asImpl().addExtraDataPattern();
}
// Immediate-members pattern. This is only valid for classes.
if (asImpl().hasImmediateMembersPattern()) {
asImpl().addImmediateMembersPattern();
}
// We're done with the pattern now.
#ifndef NDEBUG
auto finalOffset = B.getNextOffsetFromGlobal();
#endif
asImpl().emitInstantiationDefinitions();
assert(finalOffset == B.getNextOffsetFromGlobal() &&
"emitInstantiationDefinitions added members to the pattern!");
}
// Emit the fields of GenericMetadataPattern.
void layoutHeader() {
// RelativePointer<MetadataInstantiator> InstantiationFunction;
asImpl().addInstantiationFunction();
// RelativePointer<MetadataCompleter> CompletionFunction;
asImpl().addCompletionFunction();
// ClassMetadataPatternFlags PatternFlags;
asImpl().addPatternFlags();
}
void addInstantiationFunction() {
auto function = IGM.getAddrOfTypeMetadataInstantiationFunction(Target,
NotForDefinition);
B.addRelativeAddress(function);
}
void addCompletionFunction() {
if (!asImpl().hasCompletionFunction()) {
B.addInt32(0);
return;
}
auto function = IGM.getAddrOfTypeMetadataCompletionFunction(Target,
NotForDefinition);
B.addRelativeAddress(function);
}
void addPatternFlags() {
GenericMetadataPatternFlags flags = asImpl().getPatternFlags();
B.addInt32(flags.getOpaqueValue());
}
GenericMetadataPatternFlags getPatternFlags() {
GenericMetadataPatternFlags flags;
if (asImpl().hasExtraDataPattern())
flags.setHasExtraDataPattern(true);
return flags;
}
bool hasExtraDataPattern() {
return false;
}
void addExtraDataPattern() {
asImpl().addPartialPattern(asImpl().buildExtraDataPattern());
}
PartialPattern buildExtraDataPattern() {
llvm_unreachable("no extra data pattern!");
}
bool hasImmediateMembersPattern() {
return false;
}
void addImmediateMembersPattern() {
asImpl().addPartialPattern(asImpl().buildImmediateMembersPattern());
}
PartialPattern buildImmediateMembersPattern() {
llvm_unreachable("no immediate members pattern!");
}
void emitInstantiationDefinitions() {
// Force the emission of the nominal type descriptor, although we
// don't use it yet.
(void) asImpl().emitNominalTypeDescriptor();
// Emit the instantiation function.
asImpl().emitInstantiationFunction();
// Emit the completion function.
if (asImpl().hasCompletionFunction())
asImpl().emitCompletionFunction();
// Emit the instantiation cache.
asImpl().emitInstantiationCache();
}
};
template <class Impl, class DeclType>
class GenericValueMetadataBuilderBase
: public GenericMetadataBuilderBase<Impl, DeclType> {
using super = GenericMetadataBuilderBase<Impl, DeclType>;
protected:
using super::IGM;
using super::asImpl;
using super::Target;
using super::B;
template <class... T>
GenericValueMetadataBuilderBase(IRGenModule &IGM, DeclType *Target,
ConstantStructBuilder &B)
: super(IGM, Target, B) {}
SILType getLoweredType() {
return IGM.getLoweredType(Target->getDeclaredTypeInContext());
}
public:
/// Emit the fields of a GenericValueMetadataPattern.
void layoutHeader() {
super::layoutHeader();
// RelativeIndirectablePointer<const ValueWitnessTable> ValueWitnesses;
asImpl().addValueWitnessTable();
}
GenericMetadataPatternFlags getPatternFlags() {
auto flags = super::getPatternFlags();
flags.value_setMetadataKind(getMetadataKind(Target));
assert(!asImpl().hasImmediateMembersPattern());
return flags;
}
void addValueWitnessTable() {
ConstantReference table =
asImpl().emitValueWitnessTable(/*relative*/ true);
B.addRelativeAddress(table);
}
void emitInitializeMetadata(IRGenFunction &IGF,
llvm::Value *metadata,
bool isVWTMutable,
MetadataDependencyCollector *collector) {
emitInitializeValueMetadata(IGF, Target, metadata,
isVWTMutable, collector);
}
};
} // end anonymous namespace
/// Create an access function for the given type which triggers the
/// in-place initialization path.
static void
createSingletonInitializationMetadataAccessFunction(IRGenModule &IGM,
NominalTypeDecl *typeDecl,
CanType type) {
assert(!typeDecl->isGenericContext());
(void) createTypeMetadataAccessFunction(IGM, type,
CacheStrategy::SingletonInitialization,
[&](IRGenFunction &IGF,
DynamicMetadataRequest request,
llvm::Constant *cacheVariable) {
llvm::Value *descriptor =
IGF.IGM.getAddrOfTypeContextDescriptor(typeDecl, RequireMetadata);
auto responsePair =
IGF.Builder.CreateCall(IGF.IGM.getGetSingletonMetadataFn(),
{request.get(IGF), descriptor});
return MetadataResponse::handle(IGF, request, responsePair);
});
}
/// Create an access function for the given non-generic type.
static void createNonGenericMetadataAccessFunction(IRGenModule &IGM,
NominalTypeDecl *typeDecl) {
assert(!typeDecl->isGenericContext());
auto type = typeDecl->getDeclaredType()->getCanonicalType();
// If the type requires the in-place initialization pattern, use it.
if (needsSingletonMetadataInitialization(IGM, typeDecl)) {
createSingletonInitializationMetadataAccessFunction(IGM, typeDecl, type);
return;
}
// Otherwise, use the lazy pattern, which should be emitted using a
// direct reference to the metadata.
createDirectTypeMetadataAccessFunction(IGM, type, /*allow existing*/ false);
}
// Classes
/// Emit the base-offset variable for the class.
static void emitClassMetadataBaseOffset(IRGenModule &IGM,
ClassDecl *classDecl) {
// Otherwise, we know the offset at compile time, even if our
// clients do not, so just emit a constant.
auto &layout = IGM.getClassMetadataLayout(classDecl);
// Only classes defined in resilient modules, or those that have
// a resilient superclass need this.
if (!layout.hasResilientSuperclass() &&
!IGM.hasResilientMetadata(classDecl, ResilienceExpansion::Minimal)) {
return;
}
auto *offsetAddr =
IGM.getAddrOfClassMetadataBounds(classDecl, ForDefinition);
auto *offsetVar = cast<llvm::GlobalVariable>(offsetAddr);
if (layout.hasResilientSuperclass()) {
// If the superclass is resilient to us, we have to compute and
// initialize the global when we initialize the metadata.
auto init = llvm::ConstantAggregateZero::get(offsetVar->getValueType());
offsetVar->setInitializer(init);
offsetVar->setConstant(false);
return;
}
auto immediateMembersOffset = layout.getStartOfImmediateMembers();
auto size = layout.getSize();
auto negativeSizeInWords = size.AddressPoint / IGM.getPointerSize();
auto positiveSizeInWords = size.getOffsetToEnd() / IGM.getPointerSize();
auto initTy = cast<llvm::StructType>(offsetVar->getValueType());
auto *init = llvm::ConstantStruct::get(initTy, {
llvm::ConstantInt::get(IGM.SizeTy, immediateMembersOffset.getValue()),
llvm::ConstantInt::get(IGM.Int32Ty, negativeSizeInWords),
llvm::ConstantInt::get(IGM.Int32Ty, positiveSizeInWords)
});
offsetVar->setInitializer(init);
offsetVar->setConstant(true);
}
static Optional<llvm::Constant *>
getAddrOfDestructorFunction(IRGenModule &IGM, ClassDecl *classDecl) {
auto dtorRef = SILDeclRef(classDecl->getDestructor(),
SILDeclRef::Kind::Deallocator);
SILFunction *dtorFunc = IGM.getSILModule().lookUpFunction(dtorRef);
if (!dtorFunc) return llvm::None;
return IGM.getAddrOfSILFunction(dtorFunc, NotForDefinition);
}
static void emitFieldOffsetGlobals(IRGenModule &IGM,
ClassDecl *classDecl,
const ClassLayout &fragileLayout,
const ClassLayout &resilientLayout) {
for (auto prop : classDecl->getStoredProperties()) {
auto fieldInfo = fragileLayout.getFieldAccessAndElement(prop);
auto access = fieldInfo.first;
auto element = fieldInfo.second;
llvm::Constant *fieldOffsetOrZero;
if (element.hasByteOffset()) {
// Use a fixed offset if we have one.
fieldOffsetOrZero = IGM.getSize(element.getByteOffset());
} else {
// Otherwise, leave a placeholder for the runtime to populate at runtime.
fieldOffsetOrZero = IGM.getSize(Size(0));
}
switch (access) {
case FieldAccess::ConstantDirect:
case FieldAccess::NonConstantDirect: {
// Emit a global variable storing the constant field offset.
// If the superclass was imported from Objective-C, the offset
// does not include the superclass size; we rely on the
// Objective-C runtime sliding it down.
//
// TODO: Don't emit the symbol if field has a fixed offset and size
// in all resilience domains
auto offsetAddr = IGM.getAddrOfFieldOffset(prop, ForDefinition);
auto offsetVar = cast<llvm::GlobalVariable>(offsetAddr.getAddress());
offsetVar->setInitializer(fieldOffsetOrZero);
// If the offset is constant in the resilient layout, it will not change
// at runtime, and the global can be true const.
//
// If it is constant in the fragile layout only, newer Objective-C
// runtimes will still update them in place, so make sure to check the
// correct layout.
//
// The one exception to this rule is with empty fields with
// ObjC-resilient heritage. The ObjC runtime will attempt to slide
// these offsets if it slides the rest of the class, and in doing so
// it will compute a different offset than we computed statically.
// But this is ultimately unimportant because we do not care about the
// offset of an empty field.
auto resilientInfo = resilientLayout.getFieldAccessAndElement(prop);
if (resilientInfo.first == FieldAccess::ConstantDirect &&
(!resilientInfo.second.isEmpty() ||
!resilientLayout.mayRuntimeAssignNonZeroOffsetsToEmptyFields())) {
// If it is constant in the resilient layout, it should be constant in
// the fragile layout also.
assert(access == FieldAccess::ConstantDirect);
assert(element.hasByteOffset());
offsetVar->setConstant(true);
}
break;
}
case FieldAccess::ConstantIndirect:
// No global variable is needed.
break;
}
}
}
static ClassFlags getClassFlags(ClassDecl *classDecl) {
auto flags = ClassFlags();
// Set a flag if the class uses Swift refcounting.
auto type = classDecl->getDeclaredType()->getCanonicalType();
if (type->getReferenceCounting() == ReferenceCounting::Native) {
flags |= ClassFlags::UsesSwiftRefcounting;
}
// Set a flag if the class has a custom ObjC name.
DeclAttributes attrs = classDecl->getAttrs();
if (auto objc = attrs.getAttribute<ObjCAttr>()) {
if (objc->getName())
flags |= ClassFlags::HasCustomObjCName;
}
if (attrs.hasAttribute<ObjCRuntimeNameAttr>())
flags |= ClassFlags::HasCustomObjCName;
return flags;
}
namespace {
/// Base class for layout of non-generic class metadata.
template<class Impl>
class ClassMetadataBuilderBase : public ClassMetadataVisitor<Impl> {
using super = ClassMetadataVisitor<Impl>;
protected:
using super::IGM;
using super::Target;
ConstantStructBuilder &B;
const ClassLayout &FieldLayout;
const ClassMetadataLayout &MetadataLayout;
const SILVTable *VTable;
Size AddressPoint;
public:
ClassMetadataBuilderBase(IRGenModule &IGM, ClassDecl *theClass,
ConstantStructBuilder &builder,
const ClassLayout &fieldLayout)
: super(IGM, theClass), B(builder),
FieldLayout(fieldLayout),
MetadataLayout(IGM.getClassMetadataLayout(theClass)),
VTable(IGM.getSILModule().lookUpVTable(theClass)) {}
public:
void noteAddressPoint() {
ClassMetadataVisitor<Impl>::noteAddressPoint();
AddressPoint = B.getNextOffsetFromGlobal();
}
void addClassFlags() {
B.addInt32((uint32_t) getClassFlags(Target));
}
void noteResilientSuperclass() {}
void noteStartOfImmediateMembers(ClassDecl *theClass) {}
void addValueWitnessTable() {
switch (IGM.getClassMetadataStrategy(Target)) {
case ClassMetadataStrategy::Resilient:
case ClassMetadataStrategy::Singleton:
// The runtime fills in the value witness table for us.
B.add(llvm::ConstantPointerNull::get(IGM.WitnessTablePtrTy));
break;
case ClassMetadataStrategy::Update:
case ClassMetadataStrategy::FixedOrUpdate:
case ClassMetadataStrategy::Fixed: {
// FIXME: Should this check HasImported instead?
auto type = (Target->checkAncestry(AncestryFlags::ObjC)
? IGM.Context.TheUnknownObjectType
: IGM.Context.TheNativeObjectType);
auto wtable = IGM.getAddrOfValueWitnessTable(type);
B.add(wtable);
break;
}
}
}
/// The 'metadata flags' field in a class is actually a pointer to
/// the metaclass object for the class.
///
/// NONAPPLE: This is only really required for ObjC interop; maybe
/// suppress this for classes that don't need to be exposed to
/// ObjC, e.g. for non-Apple platforms?
void addMetadataFlags() {
static_assert(unsigned(MetadataKind::Class) == 0,
"class metadata kind is non-zero?");
if (IGM.ObjCInterop) {
// Get the metaclass pointer as an intptr_t.
auto metaclass = IGM.getAddrOfMetaclassObject(Target,
NotForDefinition);
auto flags =
llvm::ConstantExpr::getPtrToInt(metaclass, IGM.MetadataKindTy);
B.add(flags);
} else {
// On non-objc platforms just fill it with a null, there
// is no Objective-C metaclass.
// FIXME: Remove this to save metadata space.
// rdar://problem/18801263
B.addInt(IGM.MetadataKindTy, unsigned(MetadataKind::Class));
}
}
void addSuperclass() {
// If we might have generic ancestry, leave a placeholder since
// swift_initClassMetdata() will fill in the superclass.
switch (IGM.getClassMetadataStrategy(Target)) {
case ClassMetadataStrategy::Resilient:
case ClassMetadataStrategy::Singleton:
B.addNullPointer(IGM.TypeMetadataPtrTy);
return;
case ClassMetadataStrategy::Update:
case ClassMetadataStrategy::FixedOrUpdate:
case ClassMetadataStrategy::Fixed:
break;
}
// If this is a root class, use SwiftObject as our formal parent.
if (!Target->hasSuperclass()) {
// This is only required for ObjC interoperation.
if (!IGM.ObjCInterop) {
B.addNullPointer(IGM.TypeMetadataPtrTy);
return;
}
// We have to do getAddrOfObjCClass ourselves here because
// the ObjC runtime base needs to be ObjC-mangled but isn't
// actually imported from a clang module.
B.add(IGM.getAddrOfObjCClass(
IGM.getObjCRuntimeBaseForSwiftRootClass(Target),
NotForDefinition));
return;
}
Type type = Target->mapTypeIntoContext(Target->getSuperclass());
auto *metadata = tryEmitConstantHeapMetadataRef(
IGM, type->getCanonicalType(),
/*allowUninit*/ false);
assert(metadata != nullptr);
B.add(metadata);
}
void addDestructorFunction() {
if (auto ptr = getAddrOfDestructorFunction(IGM, Target)) {
B.add(*ptr);
} else {
// In case the optimizer removed the function. See comment in
// addMethod().
B.addNullPointer(IGM.FunctionPtrTy);
}
}
void addIVarDestroyer() {
auto dtorFunc = IGM.getAddrOfIVarInitDestroy(Target,
/*isDestroyer=*/ true,
/*isForeign=*/ false,
NotForDefinition);
if (dtorFunc) {
B.add(*dtorFunc);
} else {
B.addNullPointer(IGM.FunctionPtrTy);
}
}
llvm::Constant *emitNominalTypeDescriptor() {
return ClassContextDescriptorBuilder(IGM, Target, RequireMetadata).emit();
}
void addNominalTypeDescriptor() {
B.add(emitNominalTypeDescriptor());
}
bool canBeConstant() {
// TODO: the metadata global can actually be constant in a very
// special case: it's not a pattern, ObjC interoperation isn't
// required, there are no class fields, and there is nothing that
// needs to be runtime-adjusted.
return false;
}
void addInstanceAddressPoint() {
// Right now, we never allocate fields before the address point.
B.addInt32(0);
}
void addInstanceSize() {
if (FieldLayout.isFixedLayout()) {
B.addInt32(FieldLayout.getSize().getValue());
} else {
// Leave a zero placeholder to be filled at runtime
B.addInt32(0);
}
}
void addInstanceAlignMask() {
if (FieldLayout.isFixedLayout()) {
B.addInt16(FieldLayout.getAlignMask().getValue());
} else {
// Leave a zero placeholder to be filled at runtime
B.addInt16(0);
}
}
void addRuntimeReservedBits() {
B.addInt16(0);
}
void addClassSize() {
auto size = MetadataLayout.getSize();
B.addInt32(size.FullSize.getValue());
}
void addClassAddressPoint() {
// FIXME: Wrong
auto size = MetadataLayout.getSize();
B.addInt32(size.AddressPoint.getValue());
}
void addClassCacheData() {
// We initially fill in these fields with addresses taken from
// the ObjC runtime.
// FIXME: Remove null data altogether rdar://problem/18801263
B.add(IGM.getObjCEmptyCachePtr());
B.add(IGM.getObjCEmptyVTablePtr());
}
void addClassDataPointer() {
if (!IGM.ObjCInterop) {
// with no Objective-C runtime, just give an empty pointer with the
// swift bit set.
// FIXME: Remove null data altogether rdar://problem/18801263
B.addInt(IGM.IntPtrTy, 1);
return;
}
// Derive the RO-data.
llvm::Constant *data = emitClassPrivateData(IGM, Target);
// Set a low bit to indicate this class has Swift metadata.
auto bit = llvm::ConstantInt::get(IGM.IntPtrTy,
IGM.UseDarwinPreStableABIBit ? 1 : 2);
// Emit data + bit.
data = llvm::ConstantExpr::getPtrToInt(data, IGM.IntPtrTy);
data = llvm::ConstantExpr::getAdd(data, bit);
B.add(data);
}
void addMethod(SILDeclRef fn) {
// Find the vtable entry.
assert(VTable && "no vtable?!");
auto entry = VTable->getEntry(IGM.getSILModule(), fn);
// The class is fragile. Emit a direct reference to the vtable entry.
if (entry) {
B.add(IGM.getAddrOfSILFunction(entry->Implementation, NotForDefinition));
return;
}
// The method is removed by dead method elimination.
// It should be never called. We add a pointer to an error function.
B.addBitCast(IGM.getDeletedMethodErrorFn(), IGM.FunctionPtrTy);
}
void addPlaceholder(MissingMemberDecl *m) {
assert(m->getNumberOfVTableEntries() == 0
&& "cannot generate metadata with placeholders in it");
}
void addMethodOverride(SILDeclRef baseRef, SILDeclRef declRef) {}
void createMetadataAccessFunction() {
assert(!Target->isGenericContext());
emitClassMetadataBaseOffset(IGM, Target);
createNonGenericMetadataAccessFunction(IGM, Target);
if (IGM.getClassMetadataStrategy(Target) == ClassMetadataStrategy::Fixed)
return;
emitMetadataCompletionFunction(
IGM, Target,
[&](IRGenFunction &IGF, llvm::Value *metadata,
MetadataDependencyCollector *collector) {
emitInitializeClassMetadata(IGF, Target, FieldLayout, metadata,
collector);
});
}
};
/// A builder for non-generic class metadata which does not require any
/// runtime initialization, or that only requires runtime initialization
/// on newer Objective-C runtimes.
class FixedClassMetadataBuilder :
public ClassMetadataBuilderBase<FixedClassMetadataBuilder> {
using super = ClassMetadataBuilderBase<FixedClassMetadataBuilder>;
using super::IGM;
using super::B;
public:
FixedClassMetadataBuilder(IRGenModule &IGM, ClassDecl *theClass,
ConstantStructBuilder &builder,
const ClassLayout &fieldLayout)
: super(IGM, theClass, builder, fieldLayout) {}
void addFieldOffset(VarDecl *var) {
SILType baseType = SILType::getPrimitiveObjectType(
var->getDeclContext()->getDeclaredTypeInContext()
->getCanonicalType());
B.addInt(IGM.SizeTy, getClassFieldOffset(IGM, baseType, var).getValue());
}
void addFieldOffsetPlaceholders(MissingMemberDecl *placeholder) {
llvm_unreachable("Fixed class metadata cannot have missing members");
}
void addGenericArgument(ClassDecl *forClass) {
llvm_unreachable("Fixed class metadata cannot have generic parameters");
}
void addGenericWitnessTable(ClassDecl *forClass) {
llvm_unreachable("Fixed class metadata cannot have generic requirements");
}
};
/// A builder for non-generic class metadata with resiliently-sized
/// fields or generic ancestry.
class SingletonClassMetadataBuilder :
public ClassMetadataBuilderBase<SingletonClassMetadataBuilder> {
using super = ClassMetadataBuilderBase<SingletonClassMetadataBuilder>;
using super::IGM;
using super::B;
public:
SingletonClassMetadataBuilder(IRGenModule &IGM, ClassDecl *theClass,
ConstantStructBuilder &builder,
const ClassLayout &fieldLayout)
: super(IGM, theClass, builder, fieldLayout) {}
void addFieldOffset(VarDecl *var) {
// Field offsets are either copied from the superclass or calculated
// at runtime.
B.addInt(IGM.SizeTy, 0);
}
void addFieldOffsetPlaceholders(MissingMemberDecl *placeholder) {
for (unsigned i = 0,
e = placeholder->getNumberOfFieldOffsetVectorEntries();
i < e; ++i) {
// Emit placeholder values for some number of stored properties we
// know exist but aren't able to reference directly.
B.addInt(IGM.SizeTy, 0);
}
}
void addGenericArgument(ClassDecl *forClass) {
// Filled in at runtime.
B.addNullPointer(IGM.TypeMetadataPtrTy);
}
void addGenericWitnessTable(ClassDecl *forClass) {
// Filled in at runtime.
B.addNullPointer(IGM.WitnessTablePtrTy);
}
};
/// A builder for metadata patterns for non-generic class with
/// resilient ancestry.
class ResilientClassMetadataBuilder {
IRGenModule &IGM;
ClassDecl *Target;
ConstantStructBuilder &B;
const ClassLayout &FieldLayout;
public:
ResilientClassMetadataBuilder(IRGenModule &IGM, ClassDecl *theClass,
ConstantStructBuilder &builder,
const ClassLayout &fieldLayout)
: IGM(IGM), Target(theClass), B(builder), FieldLayout(fieldLayout) {}
llvm::Constant *emitNominalTypeDescriptor() {
return ClassContextDescriptorBuilder(IGM, Target, RequireMetadata).emit();
}
void layout() {
emitNominalTypeDescriptor();
addRelocationFunction();
addDestructorFunction();
addIVarDestroyer();
addClassFlags();
addClassDataPointer();
addMetaclass();
}
void addRelocationFunction() {
// We don't use this yet, but it's available as a future customization
// point.
B.addRelativeAddressOrNull(nullptr);
}
void addDestructorFunction() {
auto function = getAddrOfDestructorFunction(IGM, Target);
B.addRelativeAddressOrNull(function ? *function : nullptr);
}
void addIVarDestroyer() {
auto function = IGM.getAddrOfIVarInitDestroy(Target,
/*isDestroyer=*/ true,
/*isForeign=*/ false,
NotForDefinition);
B.addRelativeAddressOrNull(function ? *function : nullptr);
}
void addClassFlags() {
B.addInt32((uint32_t) getClassFlags(Target));
}
void addClassDataPointer() {
auto data = (IGM.ObjCInterop
? emitClassPrivateData(IGM, Target)
: nullptr);
B.addRelativeAddressOrNull(data);
}
void addMetaclass() {
auto metaclass = (IGM.ObjCInterop
? IGM.getAddrOfMetaclassObject(Target, NotForDefinition)
: nullptr);
B.addRelativeAddressOrNull(metaclass);
}
void createMetadataAccessFunction() {
assert(IGM.getClassMetadataStrategy(Target)
== ClassMetadataStrategy::Resilient);
assert(!Target->isGenericContext());
emitClassMetadataBaseOffset(IGM, Target);
createNonGenericMetadataAccessFunction(IGM, Target);
emitMetadataCompletionFunction(
IGM, Target,
[&](IRGenFunction &IGF, llvm::Value *metadata,
MetadataDependencyCollector *collector) {
emitInitializeClassMetadata(IGF, Target, FieldLayout, metadata,
collector);
});
}
};
/// A builder for GenericClassMetadataPattern objects.
class GenericClassMetadataBuilder :
public GenericMetadataBuilderBase<GenericClassMetadataBuilder,
ClassDecl>
{
using super = GenericMetadataBuilderBase;
const ClassLayout &FieldLayout;
Optional<ConstantAggregateBuilderBase::PlaceholderPosition>
ClassRODataOffset, MetaclassObjectOffset, MetaclassRODataOffset;
public:
GenericClassMetadataBuilder(IRGenModule &IGM, ClassDecl *theClass,
ConstantStructBuilder &B,
const ClassLayout &fieldLayout)
: super(IGM, theClass, B), FieldLayout(fieldLayout)
{
// We need special initialization of metadata objects to trick the ObjC
// runtime into initializing them.
HasDependentMetadata = true;
}
void layoutHeader() {
super::layoutHeader();
// RelativePointer<HeapObjectDestroyer> Destroy;
addDestructorFunction();
// RelativePointer<ClassIVarDestroyer> IVarDestroyer;
addIVarDestroyer();
// ClassFlags Flags;
B.addInt32((uint32_t) getClassFlags(Target));
// uint16_t ClassRODataOffset;
if (IGM.ObjCInterop)
ClassRODataOffset = B.addPlaceholderWithSize(IGM.Int16Ty);
else
B.addInt16(0);
// uint16_t MetaclassObjectOffset;
if (IGM.ObjCInterop)
MetaclassObjectOffset = B.addPlaceholderWithSize(IGM.Int16Ty);
else
B.addInt16(0);
// uint16_t MetadataRODataOffset;
if (IGM.ObjCInterop)
MetaclassRODataOffset = B.addPlaceholderWithSize(IGM.Int16Ty);
else
B.addInt16(0);
// uint16_t Reserved;
B.addInt16(0);
}
llvm::Constant *emitNominalTypeDescriptor() {
return ClassContextDescriptorBuilder(IGM, Target, RequireMetadata).emit();
}
GenericMetadataPatternFlags getPatternFlags() {
auto flags = super::getPatternFlags();
flags.class_setHasImmediateMembersPattern(hasImmediateMembersPattern());
return flags;
}
void emitInstantiationDefinitions() {
// Emit the base-offset variable.
emitClassMetadataBaseOffset(IGM, Target);
super::emitInstantiationDefinitions();
}
void addDestructorFunction() {
auto function = getAddrOfDestructorFunction(IGM, Target);
B.addRelativeAddressOrNull(function ? *function : nullptr);
}
void addIVarDestroyer() {
auto function = IGM.getAddrOfIVarInitDestroy(Target,
/*isDestroyer=*/ true,
/*isForeign=*/ false,
NotForDefinition);
B.addRelativeAddressOrNull(function ? *function : nullptr);
}
bool hasExtraDataPattern() {
return IGM.ObjCInterop;
}
PartialPattern buildExtraDataPattern() {
ConstantInitBuilder subBuilder(IGM);
auto subB = subBuilder.beginStruct();
subB.setPacked(true);
// The offset of the pattern bytes in the overall extra-data section.
// Any bytes before this will be zeroed. Currently we don't take
// advantage of this.
Size patternOffset = Size(0);
if (IGM.ObjCInterop) {
// Add the metaclass object.
B.fillPlaceholderWithInt(*MetaclassObjectOffset, IGM.Int16Ty,
IGM.getOffsetInWords(patternOffset + subB.getNextOffsetFromGlobal()));
addMetaclassObject(subB);
// Add the RO-data objects.
auto roDataPoints =
emitClassPrivateDataFields(IGM, subB, Target);
B.fillPlaceholderWithInt(*ClassRODataOffset, IGM.Int16Ty,
IGM.getOffsetInWords(patternOffset + roDataPoints.first));
B.fillPlaceholderWithInt(*MetaclassRODataOffset, IGM.Int16Ty,
IGM.getOffsetInWords(patternOffset + roDataPoints.second));
}
auto patternSize = subB.getNextOffsetFromGlobal();
auto global = subB.finishAndCreateGlobal("", IGM.getPointerAlignment(),
/*constant*/ true);
return { global, patternOffset, patternSize };
}
void addMetaclassObject(ConstantStructBuilder &B) {
// isa
ClassDecl *rootClass = getRootClassForMetaclass(IGM, Target);
auto isa = IGM.getAddrOfMetaclassObject(rootClass, NotForDefinition);
B.add(isa);
// super, which is dependent if the superclass is generic
B.addNullPointer(IGM.ObjCClassPtrTy);
// cache
B.add(IGM.getObjCEmptyCachePtr());
// vtable
B.add(IGM.getObjCEmptyVTablePtr());
// rodata, which is always dependent
B.addInt(IGM.IntPtrTy, 0);
}
bool hasImmediateMembersPattern() {
// TODO: use the real field offsets if they're known statically.
return false;
}
llvm::Value *emitAllocateMetadata(IRGenFunction &IGF,
llvm::Value *descriptor,
llvm::Value *arguments,
llvm::Value *templatePointer) {
auto metadata =
IGF.Builder.CreateCall(IGM.getAllocateGenericClassMetadataFn(),
{descriptor, arguments, templatePointer});
return metadata;
}
bool hasCompletionFunction() {
// TODO: recognize cases where this is not required.
// For example, under ObjCInterop mode we can move class realization
// into the allocation phase if the superclass is trivial and there's
// no layout to do.
return true;
}
void emitInitializeMetadata(IRGenFunction &IGF,
llvm::Value *metadata,
bool isVWTMutable,
MetadataDependencyCollector *collector) {
assert(!HasDependentVWT && "class should never have dependent VWT");
emitInitializeClassMetadata(IGF, Target, FieldLayout,
metadata, collector);
}
};
} // end anonymous namespace
/// Emit the ObjC-compatible class symbol for a class.
/// Since LLVM and many system linkers do not have a notion of relative symbol
/// references, we emit the symbol as a global asm block.
static void emitObjCClassSymbol(IRGenModule &IGM,
ClassDecl *classDecl,
llvm::Constant *metadata) {
auto entity = LinkEntity::forObjCClass(classDecl);
LinkInfo link = LinkInfo::get(IGM, entity, ForDefinition);
// Create the alias.
auto *ptrTy = cast<llvm::PointerType>(metadata->getType());
auto *alias = llvm::GlobalAlias::create(
ptrTy->getElementType(), ptrTy->getAddressSpace(), link.getLinkage(),
link.getName(), metadata, &IGM.Module);
ApplyIRLinkage({link.getLinkage(), link.getVisibility(), link.getDLLStorage()})
.to(alias);
}
/// Emit the type metadata or metadata template for a class.
void irgen::emitClassMetadata(IRGenModule &IGM, ClassDecl *classDecl,
const ClassLayout &fragileLayout,
const ClassLayout &resilientLayout) {
assert(!classDecl->isForeign());
PrettyStackTraceDecl stackTraceRAII("emitting metadata for", classDecl);
emitFieldOffsetGlobals(IGM, classDecl, fragileLayout, resilientLayout);
// Set up a dummy global to stand in for the metadata object while we produce
// relative references.
ConstantInitBuilder builder(IGM);
auto init = builder.beginStruct();
init.setPacked(true);
bool canBeConstant;
auto strategy = IGM.getClassMetadataStrategy(classDecl);
switch (strategy) {
case ClassMetadataStrategy::Resilient: {
if (classDecl->isGenericContext()) {
GenericClassMetadataBuilder builder(IGM, classDecl, init,
resilientLayout);
builder.layout();
canBeConstant = true;
builder.createMetadataAccessFunction();
break;
}
ResilientClassMetadataBuilder builder(IGM, classDecl, init,
resilientLayout);
builder.layout();
canBeConstant = true;
builder.createMetadataAccessFunction();
break;
}
case ClassMetadataStrategy::Singleton:
case ClassMetadataStrategy::Update: {
SingletonClassMetadataBuilder builder(IGM, classDecl, init,
resilientLayout);
builder.layout();
canBeConstant = builder.canBeConstant();
builder.createMetadataAccessFunction();
break;
}
case ClassMetadataStrategy::FixedOrUpdate:
case ClassMetadataStrategy::Fixed: {
FixedClassMetadataBuilder builder(IGM, classDecl, init,
fragileLayout);
builder.layout();
canBeConstant = builder.canBeConstant();
builder.createMetadataAccessFunction();
break;
}
}
CanType declaredType = classDecl->getDeclaredType()->getCanonicalType();
StringRef section{};
if (classDecl->isObjC() &&
IGM.TargetInfo.OutputObjectFormat == llvm::Triple::MachO)
section = "__DATA,__objc_data, regular";
bool isPattern = (strategy == ClassMetadataStrategy::Resilient);
auto var = IGM.defineTypeMetadata(declaredType, isPattern, canBeConstant,
init.finishAndCreateFuture(), section);
// If the class does not require dynamic initialization, or if it only
// requires dynamic initialization on a newer Objective-C runtime, add it
// to the Objctive-C class list.
if (IGM.ObjCInterop) {
switch (strategy) {
case ClassMetadataStrategy::Resilient:
// Even non-@objc classes can have Objective-C categories attached, so
// we always emit a resilient class stub as long as -enable-objc-interop
// is set.
if (hasObjCResilientClassStub(IGM, classDecl)) {
emitObjCResilientClassStub(IGM, classDecl);
if (classDecl->isObjC()) {
auto *stub = IGM.getAddrOfObjCResilientClassStub(
classDecl, NotForDefinition,
TypeMetadataAddress::AddressPoint);
emitObjCClassSymbol(IGM, classDecl, stub);
}
}
break;
case ClassMetadataStrategy::Singleton:
break;
case ClassMetadataStrategy::Update:
case ClassMetadataStrategy::FixedOrUpdate:
case ClassMetadataStrategy::Fixed:
if (classDecl->isObjC())
emitObjCClassSymbol(IGM, classDecl, var);
IGM.addObjCClass(var,
classDecl->getAttrs().hasAttribute<ObjCNonLazyRealizationAttr>());
break;
}
}
}
llvm::Value *IRGenFunction::emitInvariantLoad(Address address,
const llvm::Twine &name) {
auto load = Builder.CreateLoad(address, name);
setInvariantLoad(load);
return load;
}
void IRGenFunction::setInvariantLoad(llvm::LoadInst *load) {
load->setMetadata(IGM.InvariantMetadataID, IGM.InvariantNode);
}
void IRGenFunction::setDereferenceableLoad(llvm::LoadInst *load,
unsigned size) {
auto sizeConstant = llvm::ConstantInt::get(IGM.Int64Ty, size);
auto sizeNode = llvm::MDNode::get(IGM.LLVMContext,
llvm::ConstantAsMetadata::get(sizeConstant));
load->setMetadata(IGM.DereferenceableID, sizeNode);
}
/// Emit a load from the given metadata at a constant index.
///
/// The load is marked invariant. This function should not be called
/// on metadata objects that are in the process of being initialized.
static llvm::LoadInst *
emitInvariantLoadFromMetadataAtIndex(IRGenFunction &IGF,
llvm::Value *metadata,
int index,
llvm::Type *objectTy,
const Twine &suffix = Twine::createNull()) {
auto result = emitLoadFromMetadataAtIndex(IGF, metadata, index, objectTy,
suffix);
IGF.setInvariantLoad(result);
return result;
}
/// Given a type metadata pointer, load its value witness table.
llvm::Value *
IRGenFunction::emitValueWitnessTableRefForMetadata(llvm::Value *metadata) {
auto witness = emitInvariantLoadFromMetadataAtIndex(*this, metadata, -1,
IGM.WitnessTablePtrTy,
".valueWitnesses");
// A value witness table is dereferenceable to the number of value witness
// pointers.
// TODO: If we know the type statically has extra inhabitants, we know
// there are more witnesses.
auto numValueWitnesses
= unsigned(ValueWitness::Last_RequiredValueWitness) + 1;
setDereferenceableLoad(witness,
IGM.getPointerSize().getValue() * numValueWitnesses);
return witness;
}
/// Given a lowered SIL type, load a value witness table that represents its
/// layout.
llvm::Value *
IRGenFunction::emitValueWitnessTableRef(SILType type,
llvm::Value **metadataSlot) {
return emitValueWitnessTableRef(type, MetadataState::Complete, metadataSlot);
}
llvm::Value *
IRGenFunction::emitValueWitnessTableRef(SILType type,
DynamicMetadataRequest request,
llvm::Value **metadataSlot) {
assert(request.canResponseStatusBeIgnored());
assert(!request.isStaticallyAbstract() &&
"cannot make an abstract request for a value witness table");
// See if we have a cached projection we can use.
if (auto cached = tryGetLocalTypeDataForLayout(type,
LocalTypeDataKind::forValueWitnessTable())) {
if (metadataSlot)
*metadataSlot = emitTypeMetadataRefForLayout(type, request);
return cached;
}
auto metadata = emitTypeMetadataRefForLayout(type, request);
if (metadataSlot) *metadataSlot = metadata;
auto vwtable = emitValueWitnessTableRefForMetadata(metadata);
setScopedLocalTypeDataForLayout(type,
LocalTypeDataKind::forValueWitnessTable(),
vwtable);
return vwtable;
}
//===----------------------------------------------------------------------===//
// Value types (structs and enums)
//===----------------------------------------------------------------------===//
namespace {
/// A helper class for laying out value metadata.
template <class Base>
class ValueMetadataBuilderBase : public Base {
protected:
using Base::IGM;
using Base::Target;
using Base::asImpl;
using Base::Base;
public:
SILType getLoweredType() {
return IGM.getLoweredType(Target->getDeclaredTypeInContext());
}
/// Create the runtime data structures and functions necessary to
/// support in-place metadata initialization on this type.
void maybeCreateSingletonMetadataInitialization() {
if (!needsSingletonMetadataInitialization(IGM, Target))
return;
emitMetadataCompletionFunction(IGM, Target,
[&](IRGenFunction &IGF, llvm::Value *metadata,
MetadataDependencyCollector *collector) {
emitInitializeValueMetadata(IGF, Target, metadata,
/*vwt mutable*/true, collector);
});
}
};
}
//===----------------------------------------------------------------------===//
// Structs
//===----------------------------------------------------------------------===//
namespace {
/// An adapter for laying out struct metadata.
template <class Impl>
class StructMetadataBuilderBase
: public ValueMetadataBuilderBase<StructMetadataVisitor<Impl>> {
using super = ValueMetadataBuilderBase<StructMetadataVisitor<Impl>>;
protected:
ConstantStructBuilder &B;
using super::IGM;
using super::Target;
using super::asImpl;
using super::getLoweredType;
StructMetadataBuilderBase(IRGenModule &IGM, StructDecl *theStruct,
ConstantStructBuilder &B)
: super(IGM, theStruct), B(B) {
}
public:
void noteStartOfTypeSpecificMembers() {}
void addMetadataFlags() {
B.addInt(IGM.MetadataKindTy, unsigned(getMetadataKind(Target)));
}
llvm::Constant *emitNominalTypeDescriptor() {
auto descriptor =
StructContextDescriptorBuilder(IGM, Target, RequireMetadata).emit();
return descriptor;
}
void addNominalTypeDescriptor() {
B.add(emitNominalTypeDescriptor());
}
ConstantReference emitValueWitnessTable(bool relativeReference) {
auto type = this->Target->getDeclaredType()->getCanonicalType();
return irgen::emitValueWitnessTable(IGM, type, false, relativeReference);
}
void addValueWitnessTable() {
B.add(emitValueWitnessTable(false).getValue());
}
void addFieldOffset(VarDecl *var) {
assert(var->hasStorage() &&
"storing field offset for computed property?!");
SILType structType = getLoweredType();
llvm::Constant *offset =
emitPhysicalStructMemberFixedOffset(IGM, structType, var);
// If we have a fixed offset, add it. Otherwise, leave zero as a
// placeholder.
if (offset) {
B.add(offset);
} else {
asImpl().flagUnfilledFieldOffset();
B.addInt(IGM.Int32Ty, 0);
}
}
void noteEndOfFieldOffsets() {
B.addAlignmentPadding(super::IGM.getPointerAlignment());
}
void addGenericArgument() {
llvm_unreachable("Concrete type metadata cannot have generic parameters");
}
void addGenericWitnessTable() {
llvm_unreachable("Concrete type metadata cannot have generic requirements");
}
};
class StructMetadataBuilder :
public StructMetadataBuilderBase<StructMetadataBuilder> {
bool HasUnfilledFieldOffset = false;
public:
StructMetadataBuilder(IRGenModule &IGM, StructDecl *theStruct,
ConstantStructBuilder &B)
: StructMetadataBuilderBase(IGM, theStruct, B) {}
void flagUnfilledFieldOffset() {
HasUnfilledFieldOffset = true;
}
bool canBeConstant() {
return !HasUnfilledFieldOffset;
}
void createMetadataAccessFunction() {
createNonGenericMetadataAccessFunction(IGM, Target);
maybeCreateSingletonMetadataInitialization();
}
};
/// Emit a value witness table for a fixed-layout generic type, or a template
/// if the value witness table is dependent on generic parameters.
static ConstantReference
getValueWitnessTableForGenericValueType(IRGenModule &IGM,
NominalTypeDecl *decl,
bool &dependent) {
CanType unboundType
= decl->getDeclaredType()->getCanonicalType();
dependent = hasDependentValueWitnessTable(IGM, unboundType);
return emitValueWitnessTable(IGM, unboundType, dependent,
/*relative reference*/ true);
}
/// A builder for metadata templates.
class GenericStructMetadataBuilder :
public GenericValueMetadataBuilderBase<GenericStructMetadataBuilder,
StructDecl> {
using super = GenericValueMetadataBuilderBase;
public:
GenericStructMetadataBuilder(IRGenModule &IGM, StructDecl *theStruct,
ConstantStructBuilder &B)
: super(IGM, theStruct, B) {}
llvm::Value *emitAllocateMetadata(IRGenFunction &IGF,
llvm::Value *descriptor,
llvm::Value *arguments,
llvm::Value *templatePointer) {
auto &layout = IGM.getMetadataLayout(Target);
auto extraSize = layout.getSize().getOffsetToEnd()
- IGM.getOffsetOfStructTypeSpecificMetadataMembers();
auto extraSizeV = IGM.getSize(extraSize);
return IGF.Builder.CreateCall(IGM.getAllocateGenericValueMetadataFn(),
{descriptor, arguments, templatePointer,
extraSizeV});
}
void flagUnfilledFieldOffset() {
// We just assume this might happen.
}
llvm::Constant *emitNominalTypeDescriptor() {
return StructContextDescriptorBuilder(IGM, Target, RequireMetadata).emit();
}
ConstantReference emitValueWitnessTable(bool relativeReference) {
assert(relativeReference && "should only relative reference");
return getValueWitnessTableForGenericValueType(IGM, Target,
HasDependentVWT);
}
bool hasExtraDataPattern() {
auto &ti = IGM.getTypeInfo(getLoweredType());
if (!isa<FixedTypeInfo>(ti))
return false;
if (Target->getStoredProperties().empty())
return false;
return true;
}
/// Fill in a constant field offset vector if possible.
PartialPattern buildExtraDataPattern() {
ConstantInitBuilder builder(IGM);
auto init = builder.beginArray(IGM.Int32Ty);
struct Scanner : StructMetadataScanner<Scanner> {
SILType Type;
ConstantArrayBuilder &B;
Scanner(IRGenModule &IGM, StructDecl *target, SILType type,
ConstantArrayBuilder &B)
: StructMetadataScanner(IGM, target), Type(type), B(B) {}
void addFieldOffset(VarDecl *field) {
auto offset = emitPhysicalStructMemberFixedOffset(IGM, Type, field);
if (offset) {
B.add(offset);
return;
}
assert(IGM.getTypeInfo(Type.getFieldType(field, IGM.getSILModule()))
.isKnownEmpty(ResilienceExpansion::Maximal));
B.addInt32(0);
}
void noteEndOfFieldOffsets() {
B.addAlignmentPadding(IGM.getPointerAlignment());
}
};
Scanner(IGM, Target, getLoweredType(), init).layout();
Size vectorSize = init.getNextOffsetFromGlobal();
auto global = init.finishAndCreateGlobal("", IGM.getPointerAlignment(),
/*constant*/ true);
auto &layout = IGM.getMetadataLayout(Target);
return { global,
layout.getFieldOffsetVectorOffset().getStatic()
- IGM.getOffsetOfStructTypeSpecificMetadataMembers(),
vectorSize };
}
bool hasCompletionFunction() {
return !isa<FixedTypeInfo>(IGM.getTypeInfo(getLoweredType()));
}
};
} // end anonymous namespace
/// Emit the type metadata or metadata template for a struct.
void irgen::emitStructMetadata(IRGenModule &IGM, StructDecl *structDecl) {
PrettyStackTraceDecl stackTraceRAII("emitting metadata for", structDecl);
ConstantInitBuilder initBuilder(IGM);
auto init = initBuilder.beginStruct();
init.setPacked(true);
bool isPattern;
bool canBeConstant;
if (structDecl->isGenericContext()) {
GenericStructMetadataBuilder builder(IGM, structDecl, init);
builder.layout();
isPattern = true;
canBeConstant = true;
builder.createMetadataAccessFunction();
} else {
StructMetadataBuilder builder(IGM, structDecl, init);
builder.layout();
isPattern = false;
canBeConstant = builder.canBeConstant();
builder.createMetadataAccessFunction();
}
CanType declaredType = structDecl->getDeclaredType()->getCanonicalType();
IGM.defineTypeMetadata(declaredType, isPattern, canBeConstant,
init.finishAndCreateFuture());
}
// Enums
static Optional<Size> getConstantPayloadSize(IRGenModule &IGM,
EnumDecl *enumDecl) {
auto enumTy = enumDecl->getDeclaredTypeInContext()->getCanonicalType();
auto &enumTI = IGM.getTypeInfoForUnlowered(enumTy);
if (!enumTI.isFixedSize(ResilienceExpansion::Maximal)) {
return None;
}
assert(!enumTI.isFixedSize(ResilienceExpansion::Minimal) &&
"non-generic, non-resilient enums don't need payload size in metadata");
auto &strategy = getEnumImplStrategy(IGM, enumTy);
return Size(strategy.getPayloadSizeForMetadata());
}
namespace {
template<class Impl>
class EnumMetadataBuilderBase
: public ValueMetadataBuilderBase<EnumMetadataVisitor<Impl>> {
using super = ValueMetadataBuilderBase<EnumMetadataVisitor<Impl>>;
protected:
ConstantStructBuilder &B;
using super::IGM;
using super::Target;
EnumMetadataBuilderBase(IRGenModule &IGM, EnumDecl *theEnum,
ConstantStructBuilder &B)
: super(IGM, theEnum), B(B) {
}
public:
void noteStartOfTypeSpecificMembers() {}
void addMetadataFlags() {
B.addInt(IGM.MetadataKindTy, unsigned(getMetadataKind(Target)));
}
ConstantReference emitValueWitnessTable(bool relativeReference) {
auto type = Target->getDeclaredType()->getCanonicalType();
return irgen::emitValueWitnessTable(IGM, type, false, relativeReference);
}
void addValueWitnessTable() {
B.add(emitValueWitnessTable(/*relative*/ false).getValue());
}
llvm::Constant *emitNominalTypeDescriptor() {
auto descriptor =
EnumContextDescriptorBuilder(IGM, Target, RequireMetadata).emit();
return descriptor;
}
void addNominalTypeDescriptor() {
B.add(emitNominalTypeDescriptor());
}
void addGenericArgument() {
llvm_unreachable("Concrete type metadata cannot have generic parameters");
}
void addGenericWitnessTable() {
llvm_unreachable("Concrete type metadata cannot have generic requirements");
}
};
class EnumMetadataBuilder
: public EnumMetadataBuilderBase<EnumMetadataBuilder> {
bool HasUnfilledPayloadSize = false;
public:
EnumMetadataBuilder(IRGenModule &IGM, EnumDecl *theEnum,
ConstantStructBuilder &B)
: EnumMetadataBuilderBase(IGM, theEnum, B) {}
void addPayloadSize() {
auto payloadSize = getConstantPayloadSize(IGM, Target);
if (!payloadSize) {
B.addInt(IGM.IntPtrTy, 0);
HasUnfilledPayloadSize = true;
return;
}
B.addInt(IGM.IntPtrTy, payloadSize->getValue());
}
bool canBeConstant() {
return !HasUnfilledPayloadSize;
}
void createMetadataAccessFunction() {
createNonGenericMetadataAccessFunction(IGM, Target);
maybeCreateSingletonMetadataInitialization();
}
};
class GenericEnumMetadataBuilder
: public GenericValueMetadataBuilderBase<GenericEnumMetadataBuilder,
EnumDecl> {
using super = GenericValueMetadataBuilderBase;
public:
GenericEnumMetadataBuilder(IRGenModule &IGM, EnumDecl *theEnum,
ConstantStructBuilder &B)
: super(IGM, theEnum, B) {}
llvm::Value *emitAllocateMetadata(IRGenFunction &IGF,
llvm::Value *descriptor,
llvm::Value *arguments,
llvm::Value *templatePointer) {
auto &layout = IGM.getMetadataLayout(Target);
auto extraSize = layout.getSize().getOffsetToEnd()
- IGM.getOffsetOfEnumTypeSpecificMetadataMembers();
auto extraSizeV = IGM.getSize(extraSize);
auto metadata =
IGF.Builder.CreateCall(IGM.getAllocateGenericValueMetadataFn(),
{descriptor, arguments, templatePointer,
extraSizeV});
// Initialize the payload-size field if we have a constant value for it.
// This is so small that we just do it inline instead of bothering
// with a pattern.
if (layout.hasPayloadSizeOffset()) {
if (auto size = getConstantPayloadSize(IGM, Target)) {
auto offset = layout.getPayloadSizeOffset();
auto slot = IGF.emitAddressAtOffset(metadata, offset, IGM.SizeTy,
IGM.getPointerAlignment());
IGF.Builder.CreateStore(IGM.getSize(*size), slot);
}
}
return metadata;
}
llvm::Constant *emitNominalTypeDescriptor() {
return EnumContextDescriptorBuilder(IGM, Target, RequireMetadata).emit();
}
ConstantReference emitValueWitnessTable(bool relativeReference) {
assert(relativeReference && "should only relative reference");
return getValueWitnessTableForGenericValueType(IGM, Target,
HasDependentVWT);
}
bool hasCompletionFunction() {
return !isa<FixedTypeInfo>(IGM.getTypeInfo(getLoweredType()));
}
};
} // end anonymous namespace
void irgen::emitEnumMetadata(IRGenModule &IGM, EnumDecl *theEnum) {
PrettyStackTraceDecl stackTraceRAII("emitting metadata for", theEnum);
ConstantInitBuilder initBuilder(IGM);
auto init = initBuilder.beginStruct();
init.setPacked(true);
bool isPattern;
bool canBeConstant;
if (theEnum->isGenericContext()) {
GenericEnumMetadataBuilder builder(IGM, theEnum, init);
builder.layout();
isPattern = true;
canBeConstant = true;
builder.createMetadataAccessFunction();
} else {
EnumMetadataBuilder builder(IGM, theEnum, init);
builder.layout();
isPattern = false;
canBeConstant = builder.canBeConstant();
builder.createMetadataAccessFunction();
}
CanType declaredType = theEnum->getDeclaredType()->getCanonicalType();
IGM.defineTypeMetadata(declaredType, isPattern, canBeConstant,
init.finishAndCreateFuture());
}
llvm::Value *IRGenFunction::emitObjCSelectorRefLoad(StringRef selector) {
llvm::Constant *loadSelRef = IGM.getAddrOfObjCSelectorRef(selector);
llvm::Value *loadSel =
Builder.CreateLoad(Address(loadSelRef, IGM.getPointerAlignment()));
// When generating JIT'd code, we need to call sel_registerName() to force
// the runtime to unique the selector. For non-JIT'd code, the linker will
// do it for us.
if (IGM.IRGen.Opts.UseJIT) {
loadSel = Builder.CreateCall(IGM.getObjCSelRegisterNameFn(), loadSel);
}
return loadSel;
}
//===----------------------------------------------------------------------===//
// Foreign types
//===----------------------------------------------------------------------===//
namespace {
/// An adapter that turns a metadata layout class into a foreign metadata
/// layout class.
///
/// Foreign metadata is generated for declarations that are
/// synthesized by the Clang importer from C declarations, meaning they don't
/// have a single Swift binary that is responsible for their emission.
/// In this case, we emit the record into every binary that needs it, with
/// a header with a unique identifier string that the runtime can use to pick
/// the first-used instance as the canonical instance for a process.
template<typename Impl, typename Base>
class ForeignMetadataBuilderBase : public Base {
using super = Base;
protected:
using super::IGM;
using super::Target;
using super::asImpl;
using super::B;
template <class... T>
ForeignMetadataBuilderBase(T &&...args) : super(std::forward<T>(args)...) {}
Size AddressPoint = Size::invalid();
bool CanBeConstant = true;
public:
void noteAddressPoint() {
AddressPoint = B.getNextOffsetFromGlobal();
}
bool canBeConstant() {
return CanBeConstant;
}
Size getOffsetOfAddressPoint() const { return AddressPoint; }
void createMetadataAccessFunction() {
if (asImpl().needsMetadataCompletionFunction())
asImpl().createMetadataCompletionFunction();
auto type = cast<NominalType>(asImpl().getTargetType());
(void) createTypeMetadataAccessFunction(IGM, type, CacheStrategy::Lazy,
[&](IRGenFunction &IGF,
DynamicMetadataRequest request,
llvm::Constant *cacheVariable) {
auto candidate = IGF.IGM.getAddrOfTypeMetadata(type);
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetForeignTypeMetadataFn(),
{request.get(IGF), candidate});
call->addAttribute(llvm::AttributeList::FunctionIndex,