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GenMeta.cpp
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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.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "type-metadata-layout"
#include "swift/ABI/MetadataValues.h"
#include "swift/ABI/TypeIdentity.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/ASTMangler.h"
#include "swift/AST/Attr.h"
#include "swift/AST/CanTypeVisitor.h"
#include "swift/AST/Decl.h"
#include "swift/AST/DiagnosticsIRGen.h"
#include "swift/AST/GenericEnvironment.h"
#include "swift/AST/IRGenOptions.h"
#include "swift/AST/PrettyStackTrace.h"
#include "swift/AST/SubstitutionMap.h"
#include "swift/AST/Types.h"
#include "swift/Basic/Assertions.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 "clang/AST/Decl.h"
#include "clang/AST/DeclObjC.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 "Address.h"
#include "Callee.h"
#include "ClassLayout.h"
#include "ClassMetadataVisitor.h"
#include "ClassTypeInfo.h"
#include "ConstantBuilder.h"
#include "EnumMetadataVisitor.h"
#include "ExtendedExistential.h"
#include "Field.h"
#include "FixedTypeInfo.h"
#include "ForeignClassMetadataVisitor.h"
#include "GenArchetype.h"
#include "GenClass.h"
#include "GenDecl.h"
#include "GenPointerAuth.h"
#include "GenPoly.h"
#include "GenStruct.h"
#include "GenValueWitness.h"
#include "GenericArguments.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,
llvm::Value **slotPtr,
int index,
llvm::Type *objectTy,
const llvm::Twine &suffix = "") {
Address slot =
emitAddressOfMetadataSlotAtIndex(IGF, metadata, index, objectTy);
if (slotPtr) *slotPtr = slot.getAddress();
// 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::DXContainer:
case llvm::Triple::GOFF:
case llvm::Triple::SPIRV:
case llvm::Triple::UnknownObjectFormat:
llvm_unreachable("unknown object format");
case llvm::Triple::MachO:
var->setSection("__TEXT,__const");
break;
case llvm::Triple::ELF:
case llvm::Triple::Wasm:
var->setSection(".rodata");
break;
case llvm::Triple::XCOFF:
case llvm::Triple::COFF:
var->setSection(".rdata");
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.setHasNoFramePointer(f);
IGM.setColocateMetadataSection(f);
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)) {
auto flags = Flags(Flags::Kind::Init); // 'init' is considered static
if (auto *afd = dyn_cast<AbstractFunctionDecl>(fn))
flags = flags.withIsAsync(afd->hasAsync());
return flags;
}
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:
case AccessorKind::DistributedGet:
#include "swift/AST/AccessorKinds.def"
llvm_unreachable("these accessors never appear in protocols or v-tables");
}
llvm_unreachable("bad kind");
}();
bool hasAsync = false;
if (auto *afd = dyn_cast<AbstractFunctionDecl>(fn))
hasAsync = afd->hasAsync();
return Flags(kind).withIsInstance(!fn->isStatic()).withIsAsync(hasAsync);
}
static void buildMethodDescriptorFields(IRGenModule &IGM,
const SILVTable *VTable,
SILDeclRef fn,
ConstantStructBuilder &descriptor) {
auto *func = cast<AbstractFunctionDecl>(fn.getDecl());
// Classify the method.
using Flags = MethodDescriptorFlags;
auto flags = getMethodDescriptorFlags<Flags>(func);
// Remember if the declaration was dynamic.
if (func->shouldUseObjCDispatch())
flags = flags.withIsDynamic(true);
// Include the pointer-auth discriminator.
if (auto &schema = func->hasAsync()
? IGM.getOptions().PointerAuth.AsyncSwiftClassMethods
: IGM.getOptions().PointerAuth.SwiftClassMethods) {
auto discriminator =
PointerAuthInfo::getOtherDiscriminator(IGM, schema, fn);
flags = flags.withExtraDiscriminator(discriminator->getZExtValue());
}
// TODO: final? open?
descriptor.addInt(IGM.Int32Ty, flags.getIntValue());
if (auto entry = VTable->getEntry(IGM.getSILModule(), fn)) {
assert(entry->getKind() == SILVTable::Entry::Kind::Normal);
auto *impl = entry->getImplementation();
if (impl->isAsync()) {
llvm::Constant *implFn = IGM.getAddrOfAsyncFunctionPointer(impl);
descriptor.addRelativeAddress(implFn);
} else {
llvm::Function *implFn = IGM.getAddrOfSILFunction(impl, NotForDefinition);
descriptor.addCompactFunctionReference(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);
}
}
void IRGenModule::emitNonoverriddenMethodDescriptor(const SILVTable *VTable,
SILDeclRef declRef) {
auto entity = LinkEntity::forMethodDescriptor(declRef);
auto *var = cast<llvm::GlobalVariable>(
getAddrOfLLVMVariable(entity, ConstantInit(), DebugTypeInfo()));
if (!var->isDeclaration()) {
assert(IRGen.isLazilyReemittingNominalTypeDescriptor(VTable->getClass()));
return;
}
var->setConstant(true);
setTrueConstGlobal(var);
ConstantInitBuilder ib(*this);
ConstantStructBuilder sb(ib.beginStruct(MethodDescriptorStructTy));
buildMethodDescriptorFields(*this, VTable, declRef, sb);
auto init = sb.finishAndCreateFuture();
getAddrOfLLVMVariable(entity, init, DebugTypeInfo());
}
void IRGenModule::setVCallVisibility(llvm::GlobalVariable *var,
llvm::GlobalObject::VCallVisibility vis,
std::pair<uint64_t, uint64_t> range) {
// Insert attachment of !vcall_visibility !{ vis, range.first, range.second }
var->addMetadata(
llvm::LLVMContext::MD_vcall_visibility,
*llvm::MDNode::get(getLLVMContext(),
{
llvm::ConstantAsMetadata::get(
llvm::ConstantInt::get(Int64Ty, vis)),
llvm::ConstantAsMetadata::get(
llvm::ConstantInt::get(Int64Ty, range.first)),
llvm::ConstantAsMetadata::get(
llvm::ConstantInt::get(Int64Ty, range.second)),
}));
// Insert attachment of !typed_global_not_for_cfi !{}
var->addMetadata("typed_global_not_for_cfi",
*llvm::MDNode::get(getLLVMContext(), {}));
}
void IRGenModule::addVTableTypeMetadata(
ClassDecl *decl, llvm::GlobalVariable *var,
SmallVector<std::pair<Size, SILDeclRef>, 8> vtableEntries) {
if (vtableEntries.empty())
return;
uint64_t minOffset = UINT64_MAX;
uint64_t maxOffset = 0;
for (auto ventry : vtableEntries) {
auto method = ventry.second;
auto offset = ventry.first.getValue();
var->addTypeMetadata(offset, typeIdForMethod(*this, method));
minOffset = std::min(minOffset, offset);
maxOffset = std::max(maxOffset, offset);
}
using VCallVisibility = llvm::GlobalObject::VCallVisibility;
VCallVisibility vis = VCallVisibility::VCallVisibilityPublic;
auto AS = decl->getFormalAccessScope();
if (decl->isObjC()) {
// Swift methods are called from Objective-C via objc_MsgSend
// and thus such call sites are not taken into consideration
// by VFE in GlobalDCE. We cannot for the timebeing at least
// safely eliminate a virtual function that might be called from
// Objective-C. Setting vcall_visibility to public ensures this is
// prevented.
vis = VCallVisibility::VCallVisibilityPublic;
} else if (AS.isFileScope()) {
vis = VCallVisibility::VCallVisibilityTranslationUnit;
} else if (AS.isPrivate() || AS.isInternal()) {
vis = VCallVisibility::VCallVisibilityLinkageUnit;
} else if (getOptions().InternalizeAtLink) {
vis = VCallVisibility::VCallVisibilityLinkageUnit;
}
auto relptrSize = DataLayout.getTypeAllocSize(Int32Ty).getKnownMinValue();
setVCallVisibility(var, vis,
std::make_pair(minOffset, maxOffset + relptrSize));
}
static void addPaddingAfterGenericParamDescriptors(IRGenModule &IGM,
ConstantStructBuilder &b,
unsigned numDescriptors) {
unsigned padding = (unsigned) -numDescriptors & 3;
for (unsigned i = 0; i < padding; ++i)
b.addInt(IGM.Int8Ty, 0);
}
namespace {
struct GenericSignatureHeaderBuilder {
using PlaceholderPosition =
ConstantAggregateBuilderBase::PlaceholderPosition;
PlaceholderPosition NumParamsPP;
PlaceholderPosition NumRequirementsPP;
PlaceholderPosition NumGenericKeyArgumentsPP;
PlaceholderPosition FlagsPP;
unsigned NumParams = 0;
unsigned NumRequirements = 0;
unsigned NumGenericKeyArguments = 0;
SmallVector<CanType, 2> ShapeClasses;
SmallVector<GenericPackArgument, 2> GenericPackArguments;
InvertibleProtocolSet ConditionalInvertedProtocols;
GenericSignatureHeaderBuilder(IRGenModule &IGM,
ConstantStructBuilder &builder)
: NumParamsPP(builder.addPlaceholderWithSize(IGM.Int16Ty)),
NumRequirementsPP(builder.addPlaceholderWithSize(IGM.Int16Ty)),
NumGenericKeyArgumentsPP(builder.addPlaceholderWithSize(IGM.Int16Ty)),
FlagsPP(builder.addPlaceholderWithSize(IGM.Int16Ty)) {}
void add(const GenericArgumentMetadata &info) {
ShapeClasses.append(info.ShapeClasses.begin(),
info.ShapeClasses.end());
NumParams += info.NumParams;
NumRequirements += info.NumRequirements;
for (auto pack : info.GenericPackArguments) {
// Compute the final index.
pack.Index += NumGenericKeyArguments + ShapeClasses.size();
GenericPackArguments.push_back(pack);
}
NumGenericKeyArguments += info.NumGenericKeyArguments;
}
void finish(IRGenModule &IGM, ConstantStructBuilder &b) {
assert(GenericPackArguments.empty() == ShapeClasses.empty() &&
"Can't have one without the other");
assert(NumParams <= UINT16_MAX && "way too generic");
b.fillPlaceholderWithInt(NumParamsPP, IGM.Int16Ty, NumParams);
assert(NumRequirements <= UINT16_MAX && "way too generic");
b.fillPlaceholderWithInt(NumRequirementsPP, IGM.Int16Ty,
NumRequirements);
assert(NumGenericKeyArguments <= UINT16_MAX && "way too generic");
b.fillPlaceholderWithInt(NumGenericKeyArgumentsPP, IGM.Int16Ty,
NumGenericKeyArguments + ShapeClasses.size());
bool hasTypePacks = !GenericPackArguments.empty();
bool hasConditionalInvertedProtocols =
!ConditionalInvertedProtocols.empty();
GenericContextDescriptorFlags flags(
hasTypePacks, hasConditionalInvertedProtocols);
b.fillPlaceholderWithInt(FlagsPP, IGM.Int16Ty,
flags.getIntValue());
}
};
template<class Impl>
class ContextDescriptorBuilderBase {
protected:
Impl &asImpl() { return *static_cast<Impl*>(this); }
IRGenModule &IGM;
private:
ConstantInitBuilder InitBuilder;
protected:
ConstantStructBuilder B;
std::optional<GenericSignatureHeaderBuilder> SignatureHeader;
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().isNull(),
asImpl().isUniqueDescriptor(),
!asImpl().getInvertedProtocols().empty(),
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().addGenericPackShapeDescriptors();
asImpl().addConditionalInvertedProtocols();
asImpl().finishGenericParameters();
}
void addGenericParametersHeader() {
// Drop placeholders for the counts. We'll fill these in when we emit
// the related sections.
SignatureHeader.emplace(IGM, B);
}
void addGenericParameters() {
GenericSignature sig = asImpl().getGenericSignature();
auto metadata =
irgen::addGenericParameters(IGM, B,
asImpl().getGenericSignature(),
/*implicit=*/false);
assert(metadata.NumParams == metadata.NumParamsEmitted &&
"We can't use implicit GenericParamDescriptors here");
SignatureHeader->add(metadata);
// Pad the structure up to four bytes for the following requirements.
addPaddingAfterGenericParamDescriptors(IGM, B,
SignatureHeader->NumParams);
}
void addGenericRequirements() {
auto metadata =
irgen::addGenericRequirements(IGM, B, asImpl().getGenericSignature());
SignatureHeader->add(metadata);
}
/// Adds the set of suppressed protocols, which must be explicitly called
/// by the concrete subclasses.
void addInvertedProtocols() {
auto protocols = asImpl().getInvertedProtocols();
if (protocols.empty())
return;
B.addInt(IGM.Int16Ty, protocols.rawBits());
}
InvertibleProtocolSet getConditionalInvertedProtocols() {
return InvertibleProtocolSet();
}
void addConditionalInvertedProtocols() {
assert(asImpl().getConditionalInvertedProtocols().empty() &&
"Subclass must implement this operation");
}
void finishGenericParameters() {
SignatureHeader->finish(IGM, B);
}
void addGenericPackShapeDescriptors() {
const auto &shapes = SignatureHeader->ShapeClasses;
const auto &packArgs = SignatureHeader->GenericPackArguments;
assert(shapes.empty() == packArgs.empty() &&
"Can't have one without the other");
// If we don't have any pack arguments, there is nothing to emit.
if (packArgs.empty())
return;
// Emit the GenericPackShapeHeader first.
// NumPacks
B.addInt(IGM.Int16Ty, packArgs.size());
// NumShapes
B.addInt(IGM.Int16Ty, shapes.size());
// Emit each GenericPackShapeDescriptor collected previously.
irgen::addGenericPackShapeDescriptors(IGM, B, shapes, packArgs);
}
/// Retrieve the set of protocols that are suppressed in this context.
InvertibleProtocolSet getInvertedProtocols() {
return InvertibleProtocolSet();
}
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->getABIName().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.setColocateTypeDescriptorSection(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.setColocateTypeDescriptorSection(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.setColocateTypeDescriptorSection(var);
}
};
class ProtocolDescriptorBuilder
: public ContextDescriptorBuilderBase<ProtocolDescriptorBuilder> {
using super = ContextDescriptorBuilderBase;
ProtocolDecl *Proto;
SILDefaultWitnessTable *DefaultWitnesses;
std::optional<ConstantAggregateBuilderBase::PlaceholderPosition>
NumRequirementsInSignature, NumRequirements;
bool Resilient;
public:
ProtocolDescriptorBuilder(IRGenModule &IGM, ProtocolDecl *Proto,
SILDefaultWitnessTable *defaultWitnesses)
: super(IGM), Proto(Proto), DefaultWitnesses(defaultWitnesses),
Resilient(IGM.getSwiftModule()->isResilient()) {}
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.setColocateTypeDescriptorSection(var);
}
void addName() {
auto nameStr = IGM.getAddrOfGlobalString(Proto->getName().str(),
/*willBeRelativelyAddressed*/ true);
B.addRelativeAddress(nameStr);
}
void addRequirementSignature() {
SmallVector<Requirement, 2> requirements;
SmallVector<InverseRequirement, 2> inverses;
Proto->getRequirementSignature().getRequirementsWithInverses(
Proto, requirements, inverses);
auto metadata =
irgen::addGenericRequirements(IGM, B, Proto->getGenericSignature(),
requirements, inverses);
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);
if (auto &schema = IGM.getOptions().PointerAuth
.ProtocolAssociatedTypeAccessFunctions) {
addDiscriminator(flags, schema,
AssociatedType(entry.getAssociatedType()));
}
// Look for a default witness.
llvm::Constant *defaultImpl =
findDefaultTypeWitness(entry.getAssociatedType());
return { flags, defaultImpl };
}
if (entry.isAssociatedConformance()) {
auto flags = Flags(Flags::Kind::AssociatedConformanceAccessFunction);
if (auto &schema = IGM.getOptions().PointerAuth
.ProtocolAssociatedTypeWitnessTableAccessFunctions) {
addDiscriminator(flags, schema,
AssociatedConformance(Proto,
entry.getAssociatedConformancePath(),
entry.getAssociatedConformanceRequirement()));
}
// 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.getOptions().WitnessMethodElimination)
IGM.emitDispatchThunk(func);
{
auto *requirement = cast<AbstractFunctionDecl>(func.getDecl());
if (requirement->isDistributedThunk()) {
// when thunk, because in protocol we want access of for the thunk
IGM.emitDistributedTargetAccessor(requirement);
}
}
// Classify the function.
auto flags = getMethodDescriptorFlags<Flags>(func.getDecl());
if (auto &schema = IGM.getOptions().PointerAuth.ProtocolWitnesses) {
SILDeclRef declRef(func.getDecl(),
isa<ConstructorDecl>(func.getDecl())
? SILDeclRef::Kind::Allocator
: SILDeclRef::Kind::Func);
if (entry.getFunction().isAutoDiffDerivativeFunction())
declRef = declRef.asAutoDiffDerivativeFunction(
entry.getFunction().getAutoDiffDerivativeFunctionIdentifier());
if (entry.getFunction().isDistributedThunk()) {
flags = flags.withIsAsync(true);
declRef = declRef.asDistributed();
}
addDiscriminator(flags, schema, declRef);
}
// Look for a default witness.
llvm::Constant *defaultImpl = findDefaultWitness(func);
return { flags, defaultImpl };
}
void addDiscriminator(ProtocolRequirementFlags &flags,
const PointerAuthSchema &schema,
const PointerAuthEntity &entity) {
assert(schema);
auto discriminator =
PointerAuthInfo::getOtherDiscriminator(IGM, schema, entity);
flags = flags.withExtraDiscriminator(discriminator->getZExtValue());
}
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 =