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fuchsia / third_party / swift / d14f10d8496a8ae290f892fe586ea9a0de1d3c96 / . / lib / IRGen / 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.
//
//===----------------------------------------------------------------------===//
#include "swift/ABI/MetadataValues.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/CanTypeVisitor.h"
#include "swift/AST/ExistentialLayout.h"
#include "swift/AST/Decl.h"
#include "swift/AST/Attr.h"
#include "swift/AST/IRGenOptions.h"
#include "swift/AST/SubstitutionMap.h"
#include "swift/AST/Types.h"
#include "swift/ClangImporter/ClangModule.h"
#include "swift/IRGen/Linking.h"
#include "swift/Runtime/Metadata.h"
#include "swift/SIL/FormalLinkage.h"
#include "swift/SIL/SILModule.h"
#include "swift/SIL/TypeLowering.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 "ClassMetadataVisitor.h"
#include "ConstantBuilder.h"
#include "EnumMetadataVisitor.h"
#include "FixedTypeInfo.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 "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);
}
// FIXME: willBeRelativelyAddressed is only needed to work around an ld64 bug
// resolving relative references to coalesceable symbols.
// It should be removed when fixed. rdar://problem/22674524
static llvm::Constant *getMangledTypeName(IRGenModule &IGM, CanType type,
bool willBeRelativelyAddressed = false) {
IRGenMangler Mangler;
std::string Name = Mangler.mangleTypeForMetadata(type);
return IGM.getAddrOfGlobalString(Name, willBeRelativelyAddressed);
}
llvm::Value *irgen::emitObjCMetadataRefForMetadata(IRGenFunction &IGF,
llvm::Value *classPtr) {
classPtr = IGF.Builder.CreateBitCast(classPtr, IGF.IGM.ObjCClassPtrTy);
// Fetch the metadata for that class.
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetObjCClassMetadataFn(),
classPtr);
call->setDoesNotThrow();
call->setDoesNotAccessMemory();
return call;
}
/// Emit a reference to the Swift metadata for an Objective-C class.
static llvm::Value *emitObjCMetadataRef(IRGenFunction &IGF,
ClassDecl *theClass) {
// Derive a pointer to the Objective-C class.
auto classPtr = emitObjCHeapMetadataRef(IGF, theClass);
return emitObjCMetadataRefForMetadata(IGF, classPtr);
}
namespace {
/// A structure for collecting generic arguments for emitting a
/// nominal metadata reference. The structure produced here is
/// consumed by swift_getGenericMetadata() and must correspond to
/// the fill operations that the compiler emits for the bound decl.
///
/// FIXME: Rework to use GenericSignature instead of AllArchetypes
struct GenericArguments {
/// The values to use to initialize the arguments structure.
SmallVector<llvm::Value *, 8> Values;
SmallVector<llvm::Type *, 8> Types;
static unsigned getNumGenericArguments(IRGenModule &IGM,
NominalTypeDecl *nominal) {
GenericTypeRequirements requirements(IGM, nominal);
return unsigned(requirements.hasParentType())
+ requirements.getNumTypeRequirements();
}
void collectTypes(IRGenModule &IGM, NominalTypeDecl *nominal) {
GenericTypeRequirements requirements(IGM, nominal);
collectTypes(IGM, requirements);
}
void collectTypes(IRGenModule &IGM,
const GenericTypeRequirements &requirements) {
if (requirements.hasParentType()) {
Types.push_back(IGM.TypeMetadataPtrTy);
}
for (auto &requirement : requirements.getRequirements()) {
if (requirement.Protocol) {
Types.push_back(IGM.WitnessTablePtrTy);
} else {
Types.push_back(IGM.TypeMetadataPtrTy);
}
}
}
void collect(IRGenFunction &IGF, CanType type) {
NominalTypeDecl *decl;
CanType parentType;
if (auto nominalType = dyn_cast<NominalType>(type)) {
decl = nominalType->getDecl();
parentType = nominalType.getParent();
} else {
auto boundType = cast<BoundGenericType>(type);
decl = boundType->getDecl();
parentType = boundType.getParent();
}
GenericTypeRequirements requirements(IGF.IGM, decl);
if (requirements.hasParentType()) {
Values.push_back(IGF.emitTypeMetadataRef(parentType));
}
auto subs =
type->getContextSubstitutionMap(IGF.IGM.getSwiftModule(), decl);
requirements.enumerateFulfillments(IGF.IGM, subs,
[&](unsigned reqtIndex, CanType type,
Optional<ProtocolConformanceRef> conf) {
if (conf) {
Values.push_back(emitWitnessTableRef(IGF, type, *conf));
} else {
Values.push_back(IGF.emitTypeMetadataRef(type));
}
});
collectTypes(IGF.IGM, decl);
assert(Types.size() == Values.size());
}
};
} // end anonymous namespace
/// Given an array of polymorphic arguments as might be set up by
/// GenericArguments, bind the polymorphic parameters.
static void emitPolymorphicParametersFromArray(IRGenFunction &IGF,
NominalTypeDecl *typeDecl,
Address array) {
GenericTypeRequirements requirements(IGF.IGM, typeDecl);
array = IGF.Builder.CreateElementBitCast(array, IGF.IGM.TypeMetadataPtrTy);
auto getInContext = [&](CanType type) -> CanType {
return typeDecl->mapTypeIntoContext(type)
->getCanonicalType();
};
// If we have a parent type, it's the first parameter.
if (requirements.hasParentType()) {
auto parentType = getInContext(requirements.getParentType());
llvm::Value *parentMetadata = IGF.Builder.CreateLoad(array);
array = IGF.Builder.CreateConstArrayGEP(array, 1, IGF.IGM.getPointerSize());
IGF.bindLocalTypeDataFromTypeMetadata(parentType, IsExact, parentMetadata);
}
// Okay, bind everything else from the context.
requirements.bindFromBuffer(IGF, array, getInContext);
}
static bool isTypeErasedGenericClass(NominalTypeDecl *ntd) {
// ObjC classes are type erased.
// TODO: Unless they have magic methods...
if (auto clas = dyn_cast<ClassDecl>(ntd))
return clas->hasClangNode() && clas->isGenericContext();
return false;
}
static bool isTypeErasedGenericClassType(CanType type) {
if (auto nom = type->getAnyNominal())
return isTypeErasedGenericClass(nom);
return false;
}
// Get the type that exists at runtime to represent a compile-time type.
CanType
irgen::getRuntimeReifiedType(IRGenModule &IGM, CanType type) {
return CanType(type.transform([&](Type t) -> Type {
if (isTypeErasedGenericClassType(CanType(t))) {
return t->getAnyNominal()->getDeclaredType()->getCanonicalType();
}
return t;
}));
}
/// Attempts to return a constant heap metadata reference for a
/// class type. This is generally only valid for specific kinds of
/// ObjC reference, like superclasses or category references.
llvm::Constant *irgen::tryEmitConstantHeapMetadataRef(IRGenModule &IGM,
CanType type,
bool allowDynamicUninitialized) {
auto theDecl = type->getClassOrBoundGenericClass();
assert(theDecl && "emitting constant heap metadata ref for non-class type?");
// If the class must not require dynamic initialization --- e.g. if it
// is a super reference --- then respect everything that might impose that.
if (!allowDynamicUninitialized) {
if (doesClassMetadataRequireDynamicInitialization(IGM, theDecl))
return nullptr;
// Otherwise, just respect genericity.
} else if (theDecl->isGenericContext() && !isTypeErasedGenericClass(theDecl)){
return nullptr;
}
// For imported classes, use the ObjC class symbol.
// This incidentally cannot coincide with most of the awkward cases, like
// having parent metadata.
if (!hasKnownSwiftMetadata(IGM, theDecl))
return IGM.getAddrOfObjCClass(theDecl, NotForDefinition);
return IGM.getAddrOfTypeMetadata(type, false);
}
/// Attempts to return a constant type metadata reference for a
/// nominal type.
ConstantReference
irgen::tryEmitConstantTypeMetadataRef(IRGenModule &IGM, CanType type,
SymbolReferenceKind refKind) {
if (!isTypeMetadataAccessTrivial(IGM, type))
return ConstantReference();
return IGM.getAddrOfTypeMetadata(type, false, refKind);
}
/// Emit a reference to an ObjC class. In general, the only things
/// you're allowed to do with the address of an ObjC class symbol are
/// (1) send ObjC messages to it (in which case the message will be
/// forwarded to the real class, if one exists) or (2) put it in
/// various data sections where the ObjC runtime will properly arrange
/// things. Therefore, we must typically force the initialization of
/// a class when emitting a reference to it.
llvm::Value *irgen::emitObjCHeapMetadataRef(IRGenFunction &IGF,
ClassDecl *theClass,
bool allowUninitialized) {
// If the class is visible only through the Objective-C runtime, form the
// appropriate runtime call.
if (theClass->getForeignClassKind() == ClassDecl::ForeignKind::RuntimeOnly) {
SmallString<64> scratch;
auto className =
IGF.IGM.getAddrOfGlobalString(theClass->getObjCRuntimeName(scratch));
return IGF.Builder.CreateCall(IGF.IGM.getLookUpClassFn(), className);
}
assert(!theClass->isForeign());
Address classRef = IGF.IGM.getAddrOfObjCClassRef(theClass);
auto classObject = IGF.Builder.CreateLoad(classRef);
if (allowUninitialized) return classObject;
// TODO: memoize this the same way that we memoize Swift type metadata?
return IGF.Builder.CreateCall(IGF.IGM.getGetInitializedObjCClassFn(),
classObject);
}
/// Emit a reference to the type metadata for a foreign type.
static llvm::Value *emitForeignTypeMetadataRef(IRGenFunction &IGF,
CanType type) {
llvm::Value *candidate = IGF.IGM.getAddrOfForeignTypeMetadataCandidate(type);
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetForeignTypeMetadataFn(),
candidate);
call->addAttribute(llvm::AttributeList::FunctionIndex,
llvm::Attribute::NoUnwind);
call->addAttribute(llvm::AttributeList::FunctionIndex,
llvm::Attribute::ReadNone);
return call;
}
/// Returns a metadata reference for a nominal type.
///
/// This is only valid in a couple of special cases:
/// 1) The nominal type is generic, in which case we emit a call to the
/// generic metadata accessor function, which must be defined separately.
/// 2) The nominal type is a value type with a fixed size from this
/// resilience domain, in which case we can reference the constant
/// metadata directly.
///
/// In any other case, a metadata accessor should be called instead.
static llvm::Value *emitNominalMetadataRef(IRGenFunction &IGF,
NominalTypeDecl *theDecl,
CanType theType) {
assert(!isa<ProtocolDecl>(theDecl));
if (!theDecl->isGenericContext()) {
assert(!IGF.IGM.isResilient(theDecl, ResilienceExpansion::Maximal));
// TODO: If Obj-C interop is off, we can relax this to allow referencing
// class metadata too.
assert(isa<StructDecl>(theDecl) || isa<EnumDecl>(theDecl));
return IGF.IGM.getAddrOfTypeMetadata(theType, false);
}
// We are applying generic parameters to a generic type.
assert(theType->isSpecialized() &&
theType->getAnyNominal() == theDecl);
// Check to see if we've maybe got a local reference already.
if (auto cache = IGF.tryGetLocalTypeData(theType,
LocalTypeDataKind::forTypeMetadata()))
return cache;
// Grab the substitutions.
GenericArguments genericArgs;
genericArgs.collect(IGF, theType);
assert(genericArgs.Values.size() > 0 && "no generic args?!");
// Call the generic metadata accessor function.
llvm::Function *accessor =
IGF.IGM.getAddrOfGenericTypeMetadataAccessFunction(theDecl,
genericArgs.Types,
NotForDefinition);
auto result = IGF.Builder.CreateCall(accessor, genericArgs.Values);
result->setDoesNotThrow();
result->addAttribute(llvm::AttributeList::FunctionIndex,
llvm::Attribute::ReadNone);
IGF.setScopedLocalTypeData(theType, LocalTypeDataKind::forTypeMetadata(),
result);
return result;
}
bool irgen::hasKnownSwiftMetadata(IRGenModule &IGM, CanType type) {
if (ClassDecl *theClass = type.getClassOrBoundGenericClass()) {
return hasKnownSwiftMetadata(IGM, theClass);
}
if (auto archetype = dyn_cast<ArchetypeType>(type)) {
if (auto superclass = archetype->getSuperclass()) {
return hasKnownSwiftMetadata(IGM, superclass->getCanonicalType());
}
}
// Class existentials, etc.
return false;
}
/// Is the given class known to have Swift-compatible metadata?
bool irgen::hasKnownSwiftMetadata(IRGenModule &IGM, ClassDecl *theClass) {
// For now, the fact that a declaration was not implemented in Swift
// is enough to conclusively force us into a slower path.
// Eventually we might have an attribute here or something based on
// the deployment target.
return theClass->hasKnownSwiftImplementation();
}
/// Is it basically trivial to access the given metadata? If so, we don't
/// need a cache variable in its accessor.
bool irgen::isTypeMetadataAccessTrivial(IRGenModule &IGM, CanType type) {
assert(!type->hasArchetype());
// Value type metadata only requires dynamic initialization on first
// access if it contains a resilient type.
if (isa<StructType>(type) || isa<EnumType>(type)) {
auto nominalType = cast<NominalType>(type);
// Imported type metadata always requires an accessor.
if (isa<ClangModuleUnit>(nominalType->getDecl()->getModuleScopeContext()))
return false;
// Metadata with a non-trivial parent node always requires an accessor.
if (auto parent = nominalType.getParent())
if (!isTypeMetadataAccessTrivial(IGM, parent))
return false;
// Resiliently-sized metadata access always requires an accessor.
return (IGM.getTypeInfoForUnlowered(type).isFixedSize());
}
// The empty tuple type has a singleton metadata.
if (auto tuple = dyn_cast<TupleType>(type))
return tuple->getNumElements() == 0;
// The builtin types generally don't require metadata, but some of them
// have nodes in the runtime anyway.
if (isa<BuiltinType>(type))
return true;
// SIL box types are artificial, but for the purposes of dynamic layout,
// we use the NativeObject metadata.
if (isa<SILBoxType>(type))
return true;
// DynamicSelfType is actually local.
if (type->hasDynamicSelfType())
return true;
return false;
}
static bool hasRequiredTypeMetadataAccessFunction(NominalTypeDecl *typeDecl) {
// This needs to be kept in sync with getTypeMetadataStrategy.
if (isa<ProtocolDecl>(typeDecl))
return false;
switch (getDeclLinkage(typeDecl)) {
case FormalLinkage::PublicUnique:
case FormalLinkage::HiddenUnique:
case FormalLinkage::Private:
return true;
case FormalLinkage::PublicNonUnique:
case FormalLinkage::HiddenNonUnique:
return false;
}
llvm_unreachable("bad formal linkage");
}
/// Return the standard access strategy for getting a non-dependent
/// type metadata object.
MetadataAccessStrategy irgen::getTypeMetadataAccessStrategy(CanType type) {
// We should not be emitting accessors for partially-substituted
// generic types.
assert(!type->hasArchetype());
// Non-generic structs, enums, and classes are special cases.
//
// Note that while protocol types don't have a metadata pattern,
// we still require an accessor since we actually want to get
// the metadata for the existential type.
//
// This needs to kept in sync with hasRequiredTypeMetadataAccessPattern.
auto nominal = type->getAnyNominal();
if (nominal && !isa<ProtocolDecl>(nominal)) {
// Metadata accessors for fully-substituted generic types are
// emitted with shared linkage.
if (nominal->isGenericContext() && !nominal->isObjC()) {
if (type->isSpecialized())
return MetadataAccessStrategy::NonUniqueAccessor;
assert(type->hasUnboundGenericType());
}
// If the type doesn't guarantee that it has an access function,
// we might have to use a non-unique accessor.
// Everything else requires accessors.
switch (getDeclLinkage(nominal)) {
case FormalLinkage::PublicUnique:
return MetadataAccessStrategy::PublicUniqueAccessor;
case FormalLinkage::HiddenUnique:
return MetadataAccessStrategy::HiddenUniqueAccessor;
case FormalLinkage::Private:
return MetadataAccessStrategy::PrivateAccessor;
case FormalLinkage::PublicNonUnique:
case FormalLinkage::HiddenNonUnique:
return MetadataAccessStrategy::NonUniqueAccessor;
}
llvm_unreachable("bad formal linkage");
}
// Everything else requires a shared accessor function.
return MetadataAccessStrategy::NonUniqueAccessor;
}
/// Emit a string encoding the labels in the given tuple type.
static llvm::Constant *getTupleLabelsString(IRGenModule &IGM,
CanTupleType type) {
bool hasLabels = false;
llvm::SmallString<128> buffer;
for (auto &elt : type->getElements()) {
if (elt.hasName()) {
hasLabels = true;
buffer.append(elt.getName().str());
}
// Each label is space-terminated.
buffer += ' ';
}
// If there are no labels, use a null pointer.
if (!hasLabels) {
return llvm::ConstantPointerNull::get(IGM.Int8PtrTy);
}
// Otherwise, create a new string literal.
// This method implicitly adds a null terminator.
return IGM.getAddrOfGlobalString(buffer);
}
namespace {
/// A visitor class for emitting a reference to a metatype object.
/// This implements a "raw" access, useful for implementing cache
/// functions or for implementing dependent accesses.
///
/// If the access requires runtime initialization, that initialization
/// must be dependency-ordered-before any load that carries a dependency
/// from the resulting metadata pointer.
class EmitTypeMetadataRef
: public CanTypeVisitor<EmitTypeMetadataRef, llvm::Value *> {
private:
IRGenFunction &IGF;
public:
EmitTypeMetadataRef(IRGenFunction &IGF) : IGF(IGF) {}
#define TREAT_AS_OPAQUE(KIND) \
llvm::Value *visit##KIND##Type(KIND##Type *type) { \
return visitOpaqueType(CanType(type)); \
}
TREAT_AS_OPAQUE(BuiltinInteger)
TREAT_AS_OPAQUE(BuiltinFloat)
TREAT_AS_OPAQUE(BuiltinVector)
TREAT_AS_OPAQUE(BuiltinRawPointer)
#undef TREAT_AS_OPAQUE
llvm::Value *emitDirectMetadataRef(CanType type) {
return IGF.IGM.getAddrOfTypeMetadata(type,
/*pattern*/ false);
}
/// The given type should use opaque type info. We assume that
/// the runtime always provides an entry for such a type; right
/// now, that mapping is as one of the power-of-two integer types.
llvm::Value *visitOpaqueType(CanType type) {
auto &opaqueTI = cast<FixedTypeInfo>(IGF.IGM.getTypeInfoForLowered(type));
unsigned numBits = opaqueTI.getFixedSize().getValueInBits();
if (!llvm::isPowerOf2_32(numBits))
numBits = llvm::NextPowerOf2(numBits);
auto intTy = BuiltinIntegerType::get(numBits, IGF.IGM.Context);
return emitDirectMetadataRef(CanType(intTy));
}
llvm::Value *visitBuiltinNativeObjectType(CanBuiltinNativeObjectType type) {
return emitDirectMetadataRef(type);
}
llvm::Value *visitBuiltinBridgeObjectType(CanBuiltinBridgeObjectType type) {
return emitDirectMetadataRef(type);
}
llvm::Value *visitBuiltinUnknownObjectType(CanBuiltinUnknownObjectType type) {
return emitDirectMetadataRef(type);
}
llvm::Value *visitBuiltinUnsafeValueBufferType(
CanBuiltinUnsafeValueBufferType type) {
return emitDirectMetadataRef(type);
}
llvm::Value *visitNominalType(CanNominalType type) {
assert(!type->isExistentialType());
return emitNominalMetadataRef(IGF, type->getDecl(), type);
}
llvm::Value *visitBoundGenericType(CanBoundGenericType type) {
assert(!type->isExistentialType());
return emitNominalMetadataRef(IGF, type->getDecl(), type);
}
llvm::Value *visitTupleType(CanTupleType type) {
if (auto cached = tryGetLocal(type))
return cached;
// I think the sanest thing to do here is drop labels, but maybe
// that's not correct. If so, that's really unfortunate in a
// lot of ways.
// Er, varargs bit? Should that go in?
switch (type->getNumElements()) {
case 0: {// Special case the empty tuple, just use the global descriptor.
llvm::Constant *fullMetadata = IGF.IGM.getEmptyTupleMetadata();
llvm::Constant *indices[] = {
llvm::ConstantInt::get(IGF.IGM.Int32Ty, 0),
llvm::ConstantInt::get(IGF.IGM.Int32Ty, 1)
};
return llvm::ConstantExpr::getInBoundsGetElementPtr(
/*Ty=*/nullptr, fullMetadata, indices);
}
case 1:
// For metadata purposes, we consider a singleton tuple to be
// isomorphic to its element type.
return IGF.emitTypeMetadataRef(type.getElementType(0));
case 2: {
// Find the metadata pointer for this element.
auto elt0Metadata = IGF.emitTypeMetadataRef(type.getElementType(0));
auto elt1Metadata = IGF.emitTypeMetadataRef(type.getElementType(1));
llvm::Value *args[] = {
elt0Metadata, elt1Metadata,
getTupleLabelsString(IGF.IGM, type),
llvm::ConstantPointerNull::get(IGF.IGM.WitnessTablePtrTy) // proposed
};
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetTupleMetadata2Fn(),
args);
call->setDoesNotThrow();
return setLocal(CanType(type), call);
}
case 3: {
// Find the metadata pointer for this element.
auto elt0Metadata = IGF.emitTypeMetadataRef(type.getElementType(0));
auto elt1Metadata = IGF.emitTypeMetadataRef(type.getElementType(1));
auto elt2Metadata = IGF.emitTypeMetadataRef(type.getElementType(2));
llvm::Value *args[] = {
elt0Metadata, elt1Metadata, elt2Metadata,
getTupleLabelsString(IGF.IGM, type),
llvm::ConstantPointerNull::get(IGF.IGM.WitnessTablePtrTy) // proposed
};
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetTupleMetadata3Fn(),
args);
call->setDoesNotThrow();
return setLocal(CanType(type), call);
}
default:
// TODO: use a caching entrypoint (with all information
// out-of-line) for non-dependent tuples.
llvm::Value *pointerToFirst = nullptr; // appease -Wuninitialized
auto elements = type.getElementTypes();
auto arrayTy = llvm::ArrayType::get(IGF.IGM.TypeMetadataPtrTy,
elements.size());
Address buffer = IGF.createAlloca(arrayTy,IGF.IGM.getPointerAlignment(),
"tuple-elements");
IGF.Builder.CreateLifetimeStart(buffer,
IGF.IGM.getPointerSize() * elements.size());
for (unsigned i = 0, e = elements.size(); i != e; ++i) {
// Find the metadata pointer for this element.
llvm::Value *eltMetadata = IGF.emitTypeMetadataRef(elements[i]);
// GEP to the appropriate element and store.
Address eltPtr = IGF.Builder.CreateStructGEP(buffer, i,
IGF.IGM.getPointerSize());
IGF.Builder.CreateStore(eltMetadata, eltPtr);
// Remember the GEP to the first element.
if (i == 0) pointerToFirst = eltPtr.getAddress();
}
llvm::Value *args[] = {
llvm::ConstantInt::get(IGF.IGM.SizeTy, elements.size()),
pointerToFirst,
getTupleLabelsString(IGF.IGM, type),
llvm::ConstantPointerNull::get(IGF.IGM.WitnessTablePtrTy) // proposed
};
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetTupleMetadataFn(),
args);
call->setDoesNotThrow();
IGF.Builder.CreateLifetimeEnd(buffer,
IGF.IGM.getPointerSize() * elements.size());
return setLocal(type, call);
}
}
llvm::Value *visitGenericFunctionType(CanGenericFunctionType type) {
IGF.unimplemented(SourceLoc(),
"metadata ref for generic function type");
return llvm::UndefValue::get(IGF.IGM.TypeMetadataPtrTy);
}
llvm::Value *extractAndMarkResultType(CanFunctionType type) {
// If the function type throws, set the lower bit of the return type
// address, so that we can carry this information over to the function
// type metadata.
auto metadata = IGF.emitTypeMetadataRef(type->getResult()->
getCanonicalType());
return metadata;
}
llvm::Value *extractAndMarkInOut(CanType type) {
// If the type is inout, get the metadata for its inner object type
// instead, and then set the lowest bit to help the runtime unique
// the metadata type for this function.
if (auto inoutType = dyn_cast<InOutType>(type)) {
auto metadata = IGF.emitTypeMetadataRef(inoutType.getObjectType());
auto metadataInt = IGF.Builder.CreatePtrToInt(metadata, IGF.IGM.SizeTy);
auto inoutFlag = llvm::ConstantInt::get(IGF.IGM.SizeTy, 1);
auto marked = IGF.Builder.CreateOr(metadataInt, inoutFlag);
return IGF.Builder.CreateIntToPtr(marked, IGF.IGM.Int8PtrTy);
}
auto metadata = IGF.emitTypeMetadataRef(type);
return IGF.Builder.CreateBitCast(metadata, IGF.IGM.Int8PtrTy);
}
llvm::Value *visitFunctionType(CanFunctionType type) {
if (auto metatype = tryGetLocal(type))
return metatype;
auto resultMetadata = extractAndMarkResultType(type);
auto inputTuple = dyn_cast<TupleType>(type.getInput());
size_t numArguments = 1;
if (inputTuple && !inputTuple->isMaterializable())
numArguments = inputTuple->getNumElements();
// Map the convention to a runtime metadata value.
FunctionMetadataConvention metadataConvention;
switch (type->getRepresentation()) {
case FunctionTypeRepresentation::Swift:
metadataConvention = FunctionMetadataConvention::Swift;
break;
case FunctionTypeRepresentation::Thin:
metadataConvention = FunctionMetadataConvention::Thin;
break;
case FunctionTypeRepresentation::Block:
metadataConvention = FunctionMetadataConvention::Block;
break;
case FunctionTypeRepresentation::CFunctionPointer:
metadataConvention = FunctionMetadataConvention::CFunctionPointer;
break;
}
auto flagsVal = FunctionTypeFlags()
.withNumArguments(numArguments)
.withConvention(metadataConvention)
.withThrows(type->throws());
auto flags = llvm::ConstantInt::get(IGF.IGM.SizeTy,
flagsVal.getIntValue());
switch (numArguments) {
case 1: {
auto arg0 = (inputTuple && !inputTuple->isMaterializable()) ?
extractAndMarkInOut(inputTuple.getElementType(0))
: extractAndMarkInOut(type.getInput());
auto call = IGF.Builder.CreateCall(
IGF.IGM.getGetFunctionMetadata1Fn(),
{flags, arg0, resultMetadata});
call->setDoesNotThrow();
return setLocal(CanType(type), call);
}
case 2: {
auto arg0 = extractAndMarkInOut(inputTuple.getElementType(0));
auto arg1 = extractAndMarkInOut(inputTuple.getElementType(1));
auto call = IGF.Builder.CreateCall(
IGF.IGM.getGetFunctionMetadata2Fn(),
{flags, arg0, arg1, resultMetadata});
call->setDoesNotThrow();
return setLocal(CanType(type), call);
}
case 3: {
auto arg0 = extractAndMarkInOut(inputTuple.getElementType(0));
auto arg1 = extractAndMarkInOut(inputTuple.getElementType(1));
auto arg2 = extractAndMarkInOut(inputTuple.getElementType(2));
auto call = IGF.Builder.CreateCall(
IGF.IGM.getGetFunctionMetadata3Fn(),
{flags, arg0, arg1, arg2,
resultMetadata});
call->setDoesNotThrow();
return setLocal(CanType(type), call);
}
default:
auto arguments = inputTuple.getElementTypes();
auto arrayTy = llvm::ArrayType::get(IGF.IGM.Int8PtrTy,
arguments.size() + 2);
Address buffer = IGF.createAlloca(arrayTy,
IGF.IGM.getPointerAlignment(),
"function-arguments");
IGF.Builder.CreateLifetimeStart(buffer,
IGF.IGM.getPointerSize() * arguments.size());
Address pointerToFirstArg = IGF.Builder.CreateStructGEP(buffer, 0,
Size(0));
Address flagsPtr = IGF.Builder.CreateBitCast(pointerToFirstArg,
IGF.IGM.SizeTy->getPointerTo());
IGF.Builder.CreateStore(flags, flagsPtr);
for (size_t i = 0; i < arguments.size(); ++i) {
auto argMetadata = extractAndMarkInOut(
inputTuple.getElementType(i));
Address argPtr = IGF.Builder.CreateStructGEP(buffer, i + 1,
IGF.IGM.getPointerSize());
IGF.Builder.CreateStore(argMetadata, argPtr);
}
Address resultPtr = IGF.Builder.CreateStructGEP(buffer,
arguments.size() + 1,
IGF.IGM.getPointerSize());
resultPtr = IGF.Builder.CreateBitCast(resultPtr,
IGF.IGM.TypeMetadataPtrTy->getPointerTo());
IGF.Builder.CreateStore(resultMetadata, resultPtr);
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetFunctionMetadataFn(),
pointerToFirstArg.getAddress());
call->setDoesNotThrow();
IGF.Builder.CreateLifetimeEnd(buffer,
IGF.IGM.getPointerSize() * arguments.size());
return setLocal(type, call);
}
}
llvm::Value *visitAnyMetatypeType(CanAnyMetatypeType type) {
// FIXME: We shouldn't accept a lowered metatype here, but we need to
// represent Optional<@objc_metatype T.Type> as an AST type for ABI
// reasons.
// assert(!type->hasRepresentation()
// && "should not be asking for a representation-specific metatype "
// "metadata");
if (auto metatype = tryGetLocal(type))
return metatype;
auto instMetadata = IGF.emitTypeMetadataRef(type.getInstanceType());
auto fn = isa<MetatypeType>(type)
? IGF.IGM.getGetMetatypeMetadataFn()
: IGF.IGM.getGetExistentialMetatypeMetadataFn();
auto call = IGF.Builder.CreateCall(fn, instMetadata);
call->setDoesNotThrow();
return setLocal(type, call);
}
llvm::Value *visitModuleType(CanModuleType type) {
IGF.unimplemented(SourceLoc(), "metadata ref for module type");
return llvm::UndefValue::get(IGF.IGM.TypeMetadataPtrTy);
}
llvm::Value *visitDynamicSelfType(CanDynamicSelfType type) {
return IGF.getLocalSelfMetadata();
}
llvm::Value *emitExistentialTypeMetadata(CanType type) {
if (auto metatype = tryGetLocal(type))
return metatype;
auto layout = type.getExistentialLayout();
auto protocols = layout.getProtocols();
// Collect references to the protocol descriptors.
auto descriptorArrayTy
= llvm::ArrayType::get(IGF.IGM.ProtocolDescriptorPtrTy,
protocols.size());
Address descriptorArray = IGF.createAlloca(descriptorArrayTy,
IGF.IGM.getPointerAlignment(),
"protocols");
IGF.Builder.CreateLifetimeStart(descriptorArray,
IGF.IGM.getPointerSize() * protocols.size());
descriptorArray = IGF.Builder.CreateBitCast(descriptorArray,
IGF.IGM.ProtocolDescriptorPtrTy->getPointerTo());
unsigned index = 0;
for (auto *protoTy : protocols) {
auto *protoDecl = protoTy->getDecl();
llvm::Value *ref = emitProtocolDescriptorRef(IGF, protoDecl);
Address slot = IGF.Builder.CreateConstArrayGEP(descriptorArray,
index, IGF.IGM.getPointerSize());
IGF.Builder.CreateStore(ref, slot);
++index;
}
// Note: ProtocolClassConstraint::Class is 0, ::Any is 1.
auto classConstraint =
llvm::ConstantInt::get(IGF.IGM.Int1Ty,
!layout.requiresClass());
llvm::Value *superclassConstraint =
llvm::ConstantPointerNull::get(IGF.IGM.TypeMetadataPtrTy);
if (layout.superclass) {
superclassConstraint = IGF.emitTypeMetadataRef(
CanType(layout.superclass));
}
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetExistentialMetadataFn(),
{classConstraint,
superclassConstraint,
IGF.IGM.getSize(Size(protocols.size())),
descriptorArray.getAddress()});
call->setDoesNotThrow();
IGF.Builder.CreateLifetimeEnd(descriptorArray,
IGF.IGM.getPointerSize() * protocols.size());
return setLocal(type, call);
}
llvm::Value *visitProtocolType(CanProtocolType type) {
return emitExistentialTypeMetadata(type);
}
llvm::Value *visitProtocolCompositionType(CanProtocolCompositionType type) {
return emitExistentialTypeMetadata(type);
}
llvm::Value *visitReferenceStorageType(CanReferenceStorageType type) {
llvm_unreachable("reference storage type should have been converted by "
"SILGen");
}
llvm::Value *visitSILFunctionType(CanSILFunctionType type) {
llvm_unreachable("should not be asking for metadata of a lowered SIL "
"function type--SILGen should have used the AST type");
}
llvm::Value *visitArchetypeType(CanArchetypeType type) {
return emitArchetypeTypeMetadataRef(IGF, type);
}
llvm::Value *visitGenericTypeParamType(CanGenericTypeParamType type) {
llvm_unreachable("dependent type should have been substituted by Sema or SILGen");
}
llvm::Value *visitDependentMemberType(CanDependentMemberType type) {
llvm_unreachable("dependent type should have been substituted by Sema or SILGen");
}
llvm::Value *visitLValueType(CanLValueType type) {
llvm_unreachable("lvalue type should have been lowered by SILGen");
}
llvm::Value *visitInOutType(CanInOutType type) {
llvm_unreachable("inout type should have been lowered by SILGen");
}
llvm::Value *visitErrorType(CanErrorType type) {
llvm_unreachable("error type should not appear in IRGen");
}
llvm::Value *visitSILBlockStorageType(CanSILBlockStorageType type) {
llvm_unreachable("cannot ask for metadata of block storage");
}
llvm::Value *visitSILBoxType(CanSILBoxType type) {
// The Builtin.NativeObject metadata can stand in for boxes.
return emitDirectMetadataRef(type->getASTContext().TheNativeObjectType);
}
/// Try to find the metatype in local data.
llvm::Value *tryGetLocal(CanType type) {
return IGF.tryGetLocalTypeData(type, LocalTypeDataKind::forTypeMetadata());
}
/// Set the metatype in local data.
llvm::Value *setLocal(CanType type, llvm::Instruction *metatype) {
IGF.setScopedLocalTypeData(type, LocalTypeDataKind::forTypeMetadata(),
metatype);
return metatype;
}
};
} // end anonymous namespace
/// Emit a type metadata reference without using an accessor function.
static llvm::Value *emitDirectTypeMetadataRef(IRGenFunction &IGF,
CanType type) {
return EmitTypeMetadataRef(IGF).visit(type);
}
static Address emitAddressOfSuperclassRefInClassMetadata(IRGenFunction &IGF,
llvm::Value *metadata) {
// The superclass field in a class type is the first field past the isa.
unsigned index = 1;
Address addr(metadata, IGF.IGM.getPointerAlignment());
addr = IGF.Builder.CreateBitCast(addr,
IGF.IGM.TypeMetadataPtrTy->getPointerTo());
return IGF.Builder.CreateConstArrayGEP(addr, index, IGF.IGM.getPointerSize());
}
static bool isLoadFrom(llvm::Value *value, Address address) {
if (auto load = dyn_cast<llvm::LoadInst>(value)) {
return load->getOperand(0) == address.getAddress();
}
return false;
}
/// Emit the body of a lazy cache accessor.
///
/// If cacheVariable is null, we perform the direct access every time.
/// This is used for metadata accessors that come about due to resilience,
/// where the direct access is completely trivial.
void irgen::emitLazyCacheAccessFunction(IRGenModule &IGM,
llvm::Function *accessor,
llvm::GlobalVariable *cacheVariable,
const llvm::function_ref<llvm::Value*(IRGenFunction &IGF)> &getValue) {
accessor->setDoesNotThrow();
// This function is logically 'readnone': the caller does not need
// to reason about any side effects or stores it might perform.
accessor->setDoesNotAccessMemory();
IRGenFunction IGF(IGM, accessor);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, accessor);
// If there's no cache variable, just perform the direct access.
if (cacheVariable == nullptr) {
IGF.Builder.CreateRet(getValue(IGF));
return;
}
// Set up the cache variable.
llvm::Constant *null =
llvm::ConstantPointerNull::get(
cast<llvm::PointerType>(cacheVariable->getValueType()));
cacheVariable->setInitializer(null);
cacheVariable->setAlignment(IGM.getPointerAlignment().getValue());
Address cache(cacheVariable, IGM.getPointerAlignment());
// Okay, first thing, check the cache variable.
//
// Conceptually, this needs to establish memory ordering with the
// store we do later in the function: if the metadata value is
// non-null, we must be able to see any stores performed by the
// initialization of the metadata. However, any attempt to read
// from the metadata will be address-dependent on the loaded
// metadata pointer, which is sufficient to provide adequate
// memory ordering guarantees on all the platforms we care about:
// ARM has special rules about address dependencies, and x86's
// memory ordering is strong enough to guarantee the visibility
// even without the address dependency.
//
// And we do not need to worry about the compiler because the
// address dependency naturally forces an order to the memory
// accesses.
//
// Therefore, we can perform a completely naked load here.
// FIXME: Technically should be "consume", but that introduces barriers in the
// current LLVM ARM backend.
auto load = IGF.Builder.CreateLoad(cache);
// Make this barrier explicit when building for TSan to avoid false positives.
if (IGM.IRGen.Opts.Sanitizers & SanitizerKind::Thread)
load->setOrdering(llvm::AtomicOrdering::Acquire);
// Compare the load result against null.
auto isNullBB = IGF.createBasicBlock("cacheIsNull");
auto contBB = IGF.createBasicBlock("cont");
llvm::Value *comparison = IGF.Builder.CreateICmpEQ(load, null);
IGF.Builder.CreateCondBr(comparison, isNullBB, contBB);
auto loadBB = IGF.Builder.GetInsertBlock();
// If the load yielded null, emit the type metadata.
IGF.Builder.emitBlock(isNullBB);
llvm::Value *directResult = getValue(IGF);
// Store it back to the cache variable. This needs to be a store-release
// because it needs to propagate memory visibility to the other threads
// that can access the cache: the initializing stores might be visible
// to this thread, but they aren't transitively guaranteed to be visible
// to other threads unless this is a store-release.
//
// However, we can skip this if the value was actually loaded from the
// cache. This is a simple, if hacky, peephole that's useful for the
// code in emitInPlaceTypeMetadataAccessFunctionBody.
if (!isLoadFrom(directResult, cache)) {
IGF.Builder.CreateStore(directResult, cache)
->setAtomic(llvm::AtomicOrdering::Release);
}
IGF.Builder.CreateBr(contBB);
auto storeBB = IGF.Builder.GetInsertBlock();
// Emit the continuation block.
IGF.Builder.emitBlock(contBB);
auto phi = IGF.Builder.CreatePHI(null->getType(), 2);
phi->addIncoming(load, loadBB);
phi->addIncoming(directResult, storeBB);
IGF.Builder.CreateRet(phi);
}
static llvm::Value *emitGenericMetadataAccessFunction(IRGenFunction &IGF,
NominalTypeDecl *nominal,
GenericArguments &genericArgs) {
CanType declaredType = nominal->getDeclaredType()->getCanonicalType();
llvm::Value *metadata = IGF.IGM.getAddrOfTypeMetadata(declaredType, true);
// Collect input arguments to the generic metadata accessor, as laid out
// by the GenericArguments class.
for (auto &arg : IGF.CurFn->args())
genericArgs.Values.push_back(&arg);
assert(genericArgs.Values.size() == genericArgs.Types.size());
assert(genericArgs.Values.size() > 0 && "no generic args?!");
// Slam that information directly into the generic arguments buffer.
auto argsBufferTy =
llvm::StructType::get(IGF.IGM.LLVMContext, genericArgs.Types);
Address argsBuffer = IGF.createAlloca(argsBufferTy,
IGF.IGM.getPointerAlignment(),
"generic.arguments");
IGF.Builder.CreateLifetimeStart(argsBuffer,
IGF.IGM.getPointerSize() * genericArgs.Values.size());
for (unsigned i = 0, e = genericArgs.Values.size(); i != e; ++i) {
Address elt = IGF.Builder.CreateStructGEP(argsBuffer, i,
IGF.IGM.getPointerSize() * i);
IGF.Builder.CreateStore(genericArgs.Values[i], elt);
}
// Cast to void*.
llvm::Value *arguments =
IGF.Builder.CreateBitCast(argsBuffer.getAddress(), IGF.IGM.Int8PtrTy);
// Make the call.
auto result = IGF.Builder.CreateCall(IGF.IGM.getGetGenericMetadataFn(),
{metadata, arguments});
result->setDoesNotThrow();
result->addAttribute(llvm::AttributeList::FunctionIndex,
llvm::Attribute::ReadOnly);
IGF.Builder.CreateLifetimeEnd(argsBuffer,
IGF.IGM.getPointerSize() * genericArgs.Values.size());
return result;
}
using InPlaceMetadataInitializer =
llvm::function_ref<llvm::Value*(IRGenFunction &IGF, llvm::Value *metadata)>;
/// Emit a helper function for swift_once that performs in-place
/// initialization of the given nominal type.
static llvm::Constant *
createInPlaceMetadataInitializationFunction(IRGenModule &IGM,
CanNominalType type,
llvm::Constant *metadata,
llvm::Constant *cacheVariable,
InPlaceMetadataInitializer &&initialize) {
// There's an ignored i8* parameter.
auto fnTy = llvm::FunctionType::get(IGM.VoidTy, {IGM.Int8PtrTy},
/*variadic*/ false);
llvm::Function *fn = llvm::Function::Create(fnTy,
llvm::GlobalValue::PrivateLinkage,
Twine("initialize_metadata_")
+ type->getDecl()->getName().str(),
&IGM.Module);
fn->setAttributes(IGM.constructInitialAttributes());
// Set up the function.
IRGenFunction IGF(IGM, fn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, fn);
// 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)
fn->removeFnAttr(llvm::Attribute::SanitizeThread);
// Emit the initialization.
llvm::Value *relocatedMetadata = initialize(IGF, metadata);
// Store back to the cache variable.
IGF.Builder.CreateStore(relocatedMetadata,
Address(cacheVariable, IGM.getPointerAlignment()))
->setAtomic(llvm::AtomicOrdering::Release);
IGF.Builder.CreateRetVoid();
return fn;
}
/// Emit the function body for the type metadata accessor of a nominal type
/// that might require in-place initialization.
static llvm::Value *
emitInPlaceTypeMetadataAccessFunctionBody(IRGenFunction &IGF,
CanNominalType type,
llvm::Constant *cacheVariable,
InPlaceMetadataInitializer &&initializer) {
llvm::Constant *metadata = IGF.IGM.getAddrOfTypeMetadata(type, false);
// We might not have interesting initialization to do.
assert((cacheVariable == nullptr) ==
isTypeMetadataAccessTrivial(IGF.IGM, type));
if (!cacheVariable)
return metadata;
// Okay, we have non-trivial initialization to do.
// Ensure that we don't have multiple threads racing to do this.
llvm::GlobalVariable *onceGuard =
new llvm::GlobalVariable(IGF.IGM.Module, IGF.IGM.OnceTy, /*constant*/ false,
llvm::GlobalValue::PrivateLinkage,
llvm::Constant::getNullValue(IGF.IGM.OnceTy),
Twine(IGF.CurFn->getName()) + ".once_token");
// There's no point in performing the fast-path token check here
// because we've already checked the cache variable. We're just using
// swift_once to guarantee thread safety.
assert(cacheVariable && "lazy initialization but no cache variable");
// Create the protected function. swift_once wants this as an i8*.
llvm::Value *onceFn =
createInPlaceMetadataInitializationFunction(IGF.IGM, type, metadata,
cacheVariable,
std::move(initializer));
onceFn = IGF.Builder.CreateBitCast(onceFn, IGF.IGM.Int8PtrTy);
auto context = llvm::UndefValue::get(IGF.IGM.Int8PtrTy);
auto onceCall = IGF.Builder.CreateCall(IGF.IGM.getOnceFn(),
{onceGuard, onceFn, context});
onceCall->setCallingConv(IGF.IGM.DefaultCC);
// We can just load the cache now.
// TODO: this should be consume-ordered when LLVM supports it.
Address cacheAddr = Address(cacheVariable, IGF.IGM.getPointerAlignment());
llvm::LoadInst *relocatedMetadata = IGF.Builder.CreateLoad(cacheAddr);
// Make this barrier explicit when building for TSan to avoid false positives.
if (IGF.IGM.IRGen.Opts.Sanitizers & SanitizerKind::Thread)
relocatedMetadata->setOrdering(llvm::AtomicOrdering::Acquire);
// emitLazyCacheAccessFunction will see that the value was loaded from
// the guard variable and skip the redundant store back.
return relocatedMetadata;
}
/// Emit the body of a metadata accessor function for the given type.
///
/// This function is appropriate for ordinary situations where the
/// construction of the metadata value just involves calling idempotent
/// metadata-construction functions. It is not used for the in-place
/// initialization of non-generic nominal type metadata.
static llvm::Value *emitTypeMetadataAccessFunctionBody(IRGenFunction &IGF,
CanType type) {
assert(!type->hasArchetype() &&
"cannot emit metadata accessor for context-dependent type");
// We only take this path for That means
// everything except non-generic nominal types.
auto typeDecl = type->getAnyNominal();
if (!typeDecl)
return emitDirectTypeMetadataRef(IGF, type);
if (typeDecl->isGenericContext() &&
!(isa<ClassDecl>(typeDecl) &&
isa<ClangModuleUnit>(typeDecl->getModuleScopeContext()))) {
// This is a metadata accessor for a fully substituted generic type.
return emitDirectTypeMetadataRef(IGF, type);
}
// We should never be emitting a metadata accessor for resilient nominal
// types outside of their defining module. We'd only do that anyway for
// types that don't guarantee the existence of a non-unique access
// function, and that should never be true of a resilient type with
// external availability.
//
// (The type might still not have a statically-known layout. It just
// can't be resilient at the top level: we have to know its immediate
// members, or we can't even begin to approach the problem of emitting
// metadata for it.)
assert(!IGF.IGM.isResilient(typeDecl, ResilienceExpansion::Maximal));
// Non-native types are just wrapped in various ways.
if (auto classDecl = dyn_cast<ClassDecl>(typeDecl)) {
// We emit a completely different pattern for foreign classes.
if (classDecl->getForeignClassKind() == ClassDecl::ForeignKind::CFType) {
return emitForeignTypeMetadataRef(IGF, type);
}
// Classes that might not have Swift metadata use a different
// symbol name.
if (!hasKnownSwiftMetadata(IGF.IGM, classDecl)) {
return emitObjCMetadataRef(IGF, classDecl);
}
// Imported value types require foreign metadata uniquing.
} else if (isa<ClangModuleUnit>(typeDecl->getModuleScopeContext())) {
return emitForeignTypeMetadataRef(IGF, type);
}
// Okay, everything else is built from a Swift metadata object.
llvm::Constant *metadata = IGF.IGM.getAddrOfTypeMetadata(type, false);
// We should not be doing more serious work along this path.
assert(isTypeMetadataAccessTrivial(IGF.IGM, type));
return metadata;
}
using MetadataAccessGenerator =
llvm::function_ref<llvm::Value*(IRGenFunction &IGF, llvm::Constant *cache)>;
/// Get or create an accessor function to the given non-dependent type.
static llvm::Function *getTypeMetadataAccessFunction(IRGenModule &IGM,
CanType type,
ForDefinition_t shouldDefine,
MetadataAccessGenerator &&generator) {
assert(!type->hasArchetype());
// Type should be bound unless it's type erased.
assert(isTypeErasedGenericClassType(type)
? !isa<BoundGenericType>(type)
: !isa<UnboundGenericType>(type));
llvm::Function *accessor =
IGM.getAddrOfTypeMetadataAccessFunction(type, shouldDefine);
// If we're not supposed to define the accessor, or if we already
// have defined it, just return the pointer.
if (!shouldDefine || !accessor->empty())
return accessor;
// Okay, define the accessor.
llvm::GlobalVariable *cacheVariable = nullptr;
// If our preferred access method is to go via an accessor, it means
// there is some non-trivial computation that needs to be cached.
if (!isTypeMetadataAccessTrivial(IGM, type)) {
cacheVariable = cast<llvm::GlobalVariable>(
IGM.getAddrOfTypeMetadataLazyCacheVariable(type, ForDefinition));
if (IGM.getOptions().OptimizeForSize)
accessor->addFnAttr(llvm::Attribute::NoInline);
}
emitLazyCacheAccessFunction(IGM, accessor, cacheVariable,
[&](IRGenFunction &IGF) -> llvm::Value* {
return generator(IGF, cacheVariable);
});
return accessor;
}
/// Get or create an accessor function to the given non-dependent type.
static llvm::Function *getTypeMetadataAccessFunction(IRGenModule &IGM,
CanType type,
ForDefinition_t shouldDefine) {
return getTypeMetadataAccessFunction(IGM, type, shouldDefine,
[&](IRGenFunction &IGF,
llvm::Constant *cacheVariable) {
// We should not be called with ForDefinition for nominal types
// that require in-place initialization.
return emitTypeMetadataAccessFunctionBody(IGF, type);
});
}
/// Get or create an accessor function to the given generic type.
static llvm::Function *getGenericTypeMetadataAccessFunction(IRGenModule &IGM,
NominalTypeDecl *nominal,
ForDefinition_t shouldDefine) {
assert(nominal->isGenericContext());
assert(!isTypeErasedGenericClass(nominal));
GenericArguments genericArgs;
genericArgs.collectTypes(IGM, nominal);
llvm::Function *accessor =
IGM.getAddrOfGenericTypeMetadataAccessFunction(
nominal, genericArgs.Types, shouldDefine);
// If we're not supposed to define the accessor, or if we already
// have defined it, just return the pointer.
if (!shouldDefine || !accessor->empty())
return accessor;
if (IGM.getOptions().OptimizeForSize)
accessor->addFnAttr(llvm::Attribute::NoInline);
emitLazyCacheAccessFunction(IGM, accessor, /*cacheVariable=*/nullptr,
[&](IRGenFunction &IGF) -> llvm::Value* {
return emitGenericMetadataAccessFunction(IGF, nominal, genericArgs);
});
return accessor;
}
/// Return the type metadata access function for the given type, if it
/// is guaranteed to exist.
static llvm::Constant *
getRequiredTypeMetadataAccessFunction(IRGenModule &IGM,
NominalTypeDecl *theDecl,
ForDefinition_t shouldDefine) {
if (!hasRequiredTypeMetadataAccessFunction(theDecl))
return nullptr;
if (theDecl->isGenericContext()) {
return getGenericTypeMetadataAccessFunction(IGM, theDecl, shouldDefine);
}
CanType declaredType = theDecl->getDeclaredType()->getCanonicalType();
return getTypeMetadataAccessFunction(IGM, declaredType, shouldDefine);
}
/// Force a public metadata access function into existence if necessary
/// for the given type.
template <class BuilderTy>
static void maybeEmitNominalTypeMetadataAccessFunction(NominalTypeDecl *theDecl,
BuilderTy &builder) {
if (!hasRequiredTypeMetadataAccessFunction(theDecl))
return;
builder.createMetadataAccessFunction();
}
/// Emit a call to the type metadata accessor for the given function.
static llvm::Value *emitCallToTypeMetadataAccessFunction(IRGenFunction &IGF,
CanType type,
ForDefinition_t shouldDefine) {
// If we already cached the metadata, use it.
if (auto local =
IGF.tryGetLocalTypeData(type, LocalTypeDataKind::forTypeMetadata()))
return local;
llvm::Constant *accessor =
getTypeMetadataAccessFunction(IGF.IGM, type, shouldDefine);
llvm::CallInst *call = IGF.Builder.CreateCall(accessor, {});
call->setCallingConv(IGF.IGM.DefaultCC);
call->setDoesNotAccessMemory();
call->setDoesNotThrow();
// Save the metadata for future lookups.
IGF.setScopedLocalTypeData(type, LocalTypeDataKind::forTypeMetadata(), call);
return call;
}
/// Produce the type metadata pointer for the given type.
llvm::Value *IRGenFunction::emitTypeMetadataRef(CanType type) {
type = getRuntimeReifiedType(IGM, type);
if (type->hasArchetype() ||
isTypeMetadataAccessTrivial(IGM, type)) {
return emitDirectTypeMetadataRef(*this, type);
}
switch (getTypeMetadataAccessStrategy(type)) {
case MetadataAccessStrategy::PublicUniqueAccessor:
case MetadataAccessStrategy::HiddenUniqueAccessor:
case MetadataAccessStrategy::PrivateAccessor:
return emitCallToTypeMetadataAccessFunction(*this, type, NotForDefinition);
case MetadataAccessStrategy::NonUniqueAccessor:
return emitCallToTypeMetadataAccessFunction(*this, type, ForDefinition);
}
llvm_unreachable("bad type metadata access strategy");
}
/// Return the address of a function that will return type metadata
/// for the given non-dependent type.
llvm::Function *irgen::getOrCreateTypeMetadataAccessFunction(IRGenModule &IGM,
CanType type) {
type = getRuntimeReifiedType(IGM, type);
assert(!type->hasArchetype() &&
"cannot create global function to return dependent type metadata");
switch (getTypeMetadataAccessStrategy(type)) {
case MetadataAccessStrategy::PublicUniqueAccessor:
case MetadataAccessStrategy::HiddenUniqueAccessor:
case MetadataAccessStrategy::PrivateAccessor:
return getTypeMetadataAccessFunction(IGM, type, NotForDefinition);
case MetadataAccessStrategy::NonUniqueAccessor:
return getTypeMetadataAccessFunction(IGM, type, ForDefinition);
}
llvm_unreachable("bad type metadata access strategy");
}
namespace {
/// A visitor class for emitting a reference to a metatype object.
/// This implements a "raw" access, useful for implementing cache
/// functions or for implementing dependent accesses.
class EmitTypeMetadataRefForLayout
: public CanTypeVisitor<EmitTypeMetadataRefForLayout, llvm::Value *> {
private:
IRGenFunction &IGF;
public:
EmitTypeMetadataRefForLayout(IRGenFunction &IGF) : IGF(IGF) {}
llvm::Value *emitDirectMetadataRef(CanType type) {
return IGF.IGM.getAddrOfTypeMetadata(type, /*pattern*/ false);
}
/// For most types, we can just emit the usual metadata.
llvm::Value *visitType(CanType t) {
return IGF.emitTypeMetadataRef(t);
}
llvm::Value *visitBoundGenericEnumType(CanBoundGenericEnumType type) {
// Optionals have a lowered payload type, so we recurse here.
if (auto objectTy = CanType(type).getAnyOptionalObjectType()) {
auto payloadMetadata = visit(objectTy);
llvm::Value *args[] = { payloadMetadata };
llvm::Type *types[] = { IGF.IGM.TypeMetadataPtrTy };
// Call the generic metadata accessor function.
llvm::Function *accessor =
IGF.IGM.getAddrOfGenericTypeMetadataAccessFunction(
type->getDecl(), types, NotForDefinition);
auto result = IGF.Builder.CreateCall(accessor, args);
result->setDoesNotThrow();
result->addAttribute(llvm::AttributeList::FunctionIndex,
llvm::Attribute::ReadNone);
return result;
}
// Otherwise, generic arguments are not lowered.
return visitType(type);
}
llvm::Value *visitTupleType(CanTupleType type) {
if (auto cached = tryGetLocal(type))
return cached;
switch (type->getNumElements()) {
case 0: {// Special case the empty tuple, just use the global descriptor.
llvm::Constant *fullMetadata = IGF.IGM.getEmptyTupleMetadata();
llvm::Constant *indices[] = {
llvm::ConstantInt::get(IGF.IGM.Int32Ty, 0),
llvm::ConstantInt::get(IGF.IGM.Int32Ty, 1)
};
return llvm::ConstantExpr::getInBoundsGetElementPtr(
/*Ty=*/nullptr, fullMetadata, indices);
}
case 1:
// For layout purposes, we consider a singleton tuple to be
// isomorphic to its element type.
return visit(type.getElementType(0));
case 2: {
// Find the layout metadata pointers for these elements.
auto elt0Metadata = visit(type.getElementType(0));
auto elt1Metadata = visit(type.getElementType(1));
llvm::Value *args[] = {
elt0Metadata, elt1Metadata,
// labels don't matter for layout
llvm::ConstantPointerNull::get(IGF.IGM.Int8PtrTy),
llvm::ConstantPointerNull::get(IGF.IGM.WitnessTablePtrTy) // proposed
};
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetTupleMetadata2Fn(),
args);
call->setDoesNotThrow();
return setLocal(CanType(type), call);
}
case 3: {
// Find the layout metadata pointers for these elements.
auto elt0Metadata = visit(type.getElementType(0));
auto elt1Metadata = visit(type.getElementType(1));
auto elt2Metadata = visit(type.getElementType(2));
llvm::Value *args[] = {
elt0Metadata, elt1Metadata, elt2Metadata,
// labels don't matter for layout
llvm::ConstantPointerNull::get(IGF.IGM.Int8PtrTy),
llvm::ConstantPointerNull::get(IGF.IGM.WitnessTablePtrTy) // proposed
};
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetTupleMetadata3Fn(),
args);
call->setDoesNotThrow();
return setLocal(CanType(type), call);
}
default:
// TODO: use a caching entrypoint (with all information
// out-of-line) for non-dependent tuples.
llvm::Value *pointerToFirst = nullptr; // appease -Wuninitialized
auto elements = type.getElementTypes();
auto arrayTy = llvm::ArrayType::get(IGF.IGM.TypeMetadataPtrTy,
elements.size());
Address buffer = IGF.createAlloca(arrayTy,IGF.IGM.getPointerAlignment(),
"tuple-elements");
IGF.Builder.CreateLifetimeStart(buffer,
IGF.IGM.getPointerSize() * elements.size());
for (unsigned i = 0, e = elements.size(); i != e; ++i) {
// Find the metadata pointer for this element.
llvm::Value *eltMetadata = visit(elements[i]);
// GEP to the appropriate element and store.
Address eltPtr = IGF.Builder.CreateStructGEP(buffer, i,
IGF.IGM.getPointerSize());
IGF.Builder.CreateStore(eltMetadata, eltPtr);
// Remember the GEP to the first element.
if (i == 0) pointerToFirst = eltPtr.getAddress();
}
llvm::Value *args[] = {
llvm::ConstantInt::get(IGF.IGM.SizeTy, elements.size()),
pointerToFirst,
// labels don't matter for layout
llvm::ConstantPointerNull::get(IGF.IGM.Int8PtrTy),
llvm::ConstantPointerNull::get(IGF.IGM.WitnessTablePtrTy) // proposed
};
auto call = IGF.Builder.CreateCall(IGF.IGM.getGetTupleMetadataFn(),
args);
call->setDoesNotThrow();
IGF.Builder.CreateLifetimeEnd(buffer,
IGF.IGM.getPointerSize() * elements.size());
return setLocal(type, call);
}
}
llvm::Value *visitAnyFunctionType(CanAnyFunctionType type) {
llvm_unreachable("not a SIL type");
}
llvm::Value *visitSILFunctionType(CanSILFunctionType type) {
// All function types have the same layout regardless of arguments or
// abstraction level. Use the metadata for () -> () for thick functions,
// or Builtin.UnknownObject for block functions.
auto &C = type->getASTContext();
switch (type->getRepresentation()) {
case SILFunctionType::Representation::Thin:
case SILFunctionType::Representation::Method:
case SILFunctionType::Representation::WitnessMethod:
case SILFunctionType::Representation::ObjCMethod:
case SILFunctionType::Representation::CFunctionPointer:
case SILFunctionType::Representation::Closure:
// A thin function looks like a plain pointer.
// FIXME: Except for extra inhabitants?
return emitDirectMetadataRef(C.TheRawPointerType);
case SILFunctionType::Representation::Thick:
// All function types look like () -> ().
// FIXME: It'd be nice not to have to call through the runtime here.
return IGF.emitTypeMetadataRef(
CanFunctionType::get(AnyFunctionType::CanParamArrayRef({ }),
C.TheEmptyTupleType,
AnyFunctionType::ExtInfo()));
case SILFunctionType::Representation::Block:
// All block types look like Builtin.UnknownObject.
return emitDirectMetadataRef(C.TheUnknownObjectType);
}
llvm_unreachable("Not a valid SILFunctionType.");
}
llvm::Value *visitAnyMetatypeType(CanAnyMetatypeType type) {
assert(type->hasRepresentation()
&& "not a lowered metatype");
switch (type->getRepresentation()) {
case MetatypeRepresentation::Thin: {
// Thin metatypes are empty, so they look like the empty tuple type.
llvm::Constant *fullMetadata = IGF.IGM.getEmptyTupleMetadata();
llvm::Constant *indices[] = {
llvm::ConstantInt::get(IGF.IGM.Int32Ty, 0),
llvm::ConstantInt::get(IGF.IGM.Int32Ty, 1)
};
return llvm::ConstantExpr::getInBoundsGetElementPtr(
/*Ty=*/nullptr, fullMetadata, indices);
}
case MetatypeRepresentation::Thick:
case MetatypeRepresentation::ObjC:
// Thick and ObjC metatypes look like pointers with extra inhabitants.
// Get the metatype metadata from the runtime.
// FIXME: It'd be nice not to need a runtime call here.
return IGF.emitTypeMetadataRef(type);
}
llvm_unreachable("Not a valid MetatypeRepresentation.");
}
/// Try to find the metatype in local data.
llvm::Value *tryGetLocal(CanType type) {
return IGF.tryGetLocalTypeDataForLayout(
IGF.IGM.getLoweredType(type),
LocalTypeDataKind::forTypeMetadata());
}
/// Set the metatype in local data.
llvm::Value *setLocal(CanType type, llvm::Instruction *metatype) {
IGF.setScopedLocalTypeDataForLayout(IGF.IGM.getLoweredType(type),
LocalTypeDataKind::forTypeMetadata(),
metatype);
return metatype;
}
};
} // end anonymous namespace
llvm::Value *IRGenFunction::emitTypeMetadataRefForLayout(SILType type) {
return EmitTypeMetadataRefForLayout(*this).visit(type.getSwiftRValueType());
}
namespace {
/// A visitor class for emitting a reference to a type layout struct.
/// There are a few ways we can emit it:
///
/// - If the type is fixed-layout and we have visibility of its value
/// witness table (or one close enough), we can project the layout struct
/// from it.
/// - If the type is fixed layout, we can emit our own copy of the layout
/// struct.
/// - If the type is dynamic-layout, we have to instantiate its metadata
/// and project out its metadata. (FIXME: This leads to deadlocks in
/// recursive cases, though we can avoid many deadlocks because most
/// valid recursive types bottom out in fixed-sized types like classes
/// or pointers.)
class EmitTypeLayoutRef
: public CanTypeVisitor<EmitTypeLayoutRef, llvm::Value *> {
private:
IRGenFunction &IGF;
public:
EmitTypeLayoutRef(IRGenFunction &IGF) : IGF(IGF) {}
llvm::Value *emitFromValueWitnessTablePointer(llvm::Value *vwtable) {
llvm::Value *indexConstant = llvm::ConstantInt::get(IGF.IGM.Int32Ty,
(unsigned)ValueWitness::First_TypeLayoutWitness);
return IGF.Builder.CreateInBoundsGEP(IGF.IGM.Int8PtrTy, vwtable,
indexConstant);
}
/// Emit the type layout by projecting it from a value witness table to
/// which we have linkage.
llvm::Value *emitFromValueWitnessTable(CanType t) {
auto *vwtable = IGF.IGM.getAddrOfValueWitnessTable(t);
return emitFromValueWitnessTablePointer(vwtable);
}
/// Emit the type layout by projecting it from dynamic type metadata.
llvm::Value *emitFromTypeMetadata(CanType t) {
auto *vwtable = IGF.emitValueWitnessTableRef(IGF.IGM.getLoweredType(t));
return emitFromValueWitnessTablePointer(vwtable);
}
bool hasVisibleValueWitnessTable(CanType t) const {
// Some builtin and structural types have value witnesses exported from
// the runtime.
auto &C = IGF.IGM.Context;
if (t == C.TheEmptyTupleType
|| t == C.TheNativeObjectType
|| t == C.TheUnknownObjectType
|| t == C.TheBridgeObjectType
|| t == C.TheRawPointerType)
return true;
if (auto intTy = dyn_cast<BuiltinIntegerType>(t)) {
auto width = intTy->getWidth();
if (width.isPointerWidth())
return true;
if (width.isFixedWidth()) {
switch (width.getFixedWidth()) {
case 8:
case 16:
case 32:
case 64:
case 128:
case 256:
return true;
default:
return false;
}
}
return false;
}
// TODO: If a nominal type is in the same source file as we're currently
// emitting, we would be able to see its value witness table.
return false;
}
/// Fallback default implementation.
llvm::Value *visitType(CanType t) {
auto silTy = IGF.IGM.getLoweredType(t);
auto &ti = IGF.getTypeInfo(silTy);
// If the type is in the same source file, or has a common value
// witness table exported from the runtime, we can project from the
// value witness table instead of emitting a new record.
if (hasVisibleValueWitnessTable(t))
return emitFromValueWitnessTable(t);
// If the type is a singleton aggregate, the field's layout is equivalent
// to the aggregate's.
if (SILType singletonFieldTy = getSingletonAggregateFieldType(IGF.IGM,
silTy, ResilienceExpansion::Maximal))
return visit(singletonFieldTy.getSwiftRValueType());
// If the type is fixed-layout, emit a copy of its layout.
if (auto fixed = dyn_cast<FixedTypeInfo>(&ti))
return IGF.IGM.emitFixedTypeLayout(t, *fixed);
return emitFromTypeMetadata(t);
}
llvm::Value *visitAnyFunctionType(CanAnyFunctionType type) {
llvm_unreachable("not a SIL type");
}
llvm::Value *visitSILFunctionType(CanSILFunctionType type) {
// All function types have the same layout regardless of arguments or
// abstraction level. Use the value witness table for
// @convention(blah) () -> () from the runtime.
auto &C = type->getASTContext();
switch (type->getRepresentation()) {
case SILFunctionType::Representation::Thin:
case SILFunctionType::Representation::Method:
case SILFunctionType::Representation::WitnessMethod:
case SILFunctionType::Representation::ObjCMethod:
case SILFunctionType::Representation::CFunctionPointer:
case SILFunctionType::Representation::Closure:
// A thin function looks like a plain pointer.
// FIXME: Except for extra inhabitants?
return emitFromValueWitnessTable(C.TheRawPointerType);
case SILFunctionType::Representation::Thick:
// All function types look like () -> ().
return emitFromValueWitnessTable(
CanFunctionType::get(AnyFunctionType::CanParamArrayRef({}),
C.TheEmptyTupleType,
AnyFunctionType::ExtInfo()));
case SILFunctionType::Representation::Block:
// All block types look like Builtin.UnknownObject.
return emitFromValueWitnessTable(C.TheUnknownObjectType);
}
llvm_unreachable("Not a valid SILFunctionType.");
}
llvm::Value *visitAnyMetatypeType(CanAnyMetatypeType type) {
assert(type->hasRepresentation()
&& "not a lowered metatype");
switch (type->getRepresentation()) {
case MetatypeRepresentation::Thin: {
// Thin metatypes are empty, so they look like the empty tuple type.
return emitFromValueWitnessTable(IGF.IGM.Context.TheEmptyTupleType);
}
case MetatypeRepresentation::Thick:
case MetatypeRepresentation::ObjC:
// Thick metatypes look like pointers with spare bits.
return emitFromValueWitnessTable(
CanMetatypeType::get(IGF.IGM.Context.TheNativeObjectType));
}
llvm_unreachable("Not a valid MetatypeRepresentation.");
}
llvm::Value *visitAnyClassType(ClassDecl *classDecl) {
// All class types have the same layout.
auto type = classDecl->getDeclaredType()->getCanonicalType();
switch (getReferenceCountingForType(IGF.IGM, type)) {
case ReferenceCounting::Native:
return emitFromValueWitnessTable(IGF.IGM.Context.TheNativeObjectType);
case ReferenceCounting::ObjC:
case ReferenceCounting::Block:
case ReferenceCounting::Unknown:
return emitFromValueWitnessTable(IGF.IGM.Context.TheUnknownObjectType);
case ReferenceCounting::Bridge:
case ReferenceCounting::Error:
llvm_unreachable("classes shouldn't have this kind of refcounting");
}
llvm_unreachable("Not a valid ReferenceCounting.");
}
llvm::Value *visitClassType(CanClassType type) {
return visitAnyClassType(type->getClassOrBoundGenericClass());
}
llvm::Value *visitBoundGenericClassType(CanBoundGenericClassType type) {
return visitAnyClassType(type->getClassOrBoundGenericClass());
}
llvm::Value *visitReferenceStorageType(CanReferenceStorageType type) {
// Other reference storage types all have the same layout for their
// storage qualification and the reference counting of their underlying
// object.
auto &C = IGF.IGM.Context;
CanType referent;
switch (type->getOwnership()) {
case Ownership::Strong:
llvm_unreachable("shouldn't be a ReferenceStorageType");
case Ownership::Weak:
referent = type.getReferentType().getAnyOptionalObjectType();
break;
case Ownership::Unmanaged:
case Ownership::Unowned:
referent = type.getReferentType();
break;
}
// Reference storage types with witness tables need open-coded layouts.
// TODO: Maybe we could provide prefabs for 1 witness table.
if (referent.isExistentialType()) {
auto layout = referent.getExistentialLayout();
for (auto *protoTy : layout.getProtocols()) {
auto *protoDecl = protoTy->getDecl();
if (IGF.getSILTypes().protocolRequiresWitnessTable(protoDecl))
return visitType(type);
}
}
// Unmanaged references are plain pointers with extra inhabitants,
// which look like thick metatypes.
//
// FIXME: This sounds wrong, an Objective-C tagged pointer could be
// stored in an unmanaged reference for instance.
if (type->getOwnership() == Ownership::Unmanaged) {
auto metatype = CanMetatypeType::get(C.TheNativeObjectType);
return emitFromValueWitnessTable(metatype);
}
CanType valueWitnessReferent;
switch (getReferenceCountingForType(IGF.IGM, referent)) {
case ReferenceCounting::Unknown:
case ReferenceCounting::Block:
case ReferenceCounting::ObjC:
valueWitnessReferent = C.TheUnknownObjectType;
break;
case ReferenceCounting::Native:
valueWitnessReferent = C.TheNativeObjectType;
break;
case ReferenceCounting::Bridge:
valueWitnessReferent = C.TheBridgeObjectType;
break;
case ReferenceCounting::Error:
llvm_unreachable("shouldn't be possible");
}
// Get the reference storage type of the builtin object whose value
// witness we can borrow.
if (type->getOwnership() == Ownership::Weak)
valueWitnessReferent = OptionalType::get(valueWitnessReferent)
->getCanonicalType();
auto valueWitnessType = CanReferenceStorageType::get(valueWitnessReferent,
type->getOwnership());
return emitFromValueWitnessTable(valueWitnessType);
}
};
} // end anonymous namespace
llvm::Value *IRGenFunction::emitTypeLayoutRef(SILType type) {
return EmitTypeLayoutRef(*this).visit(type.getSwiftRValueType());
}
void IRGenModule::setTrueConstGlobal(llvm::GlobalVariable *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:
llvm_unreachable("web assembly object format is not supported.");
break;
}
}
/// Produce the heap metadata pointer for the given class type. For
/// Swift-defined types, this is equivalent to the metatype for the
/// class, but for Objective-C-defined types, this is the class
/// object.
llvm::Value *irgen::emitClassHeapMetadataRef(IRGenFunction &IGF, CanType type,
MetadataValueType desiredType,
bool allowUninitialized) {
assert(type->mayHaveSuperclass());
// Archetypes may or may not be ObjC classes and need unwrapping to get at
// the class object.
if (auto archetype = dyn_cast<ArchetypeType>(type)) {
// Look up the Swift metadata from context.
llvm::Value *archetypeMeta = IGF.emitTypeMetadataRef(type);
// Get the class pointer.
auto classPtr = emitClassHeapMetadataRefForMetatype(IGF, archetypeMeta,
archetype);
if (desiredType == MetadataValueType::ObjCClass)
classPtr = IGF.Builder.CreateBitCast(classPtr, IGF.IGM.ObjCClassPtrTy);
return classPtr;
}
if (ClassDecl *theClass = type->getClassOrBoundGenericClass()) {
if (!hasKnownSwiftMetadata(IGF.IGM, theClass)) {
llvm::Value *result =
emitObjCHeapMetadataRef(IGF, theClass, allowUninitialized);
if (desiredType == MetadataValueType::TypeMetadata)
result = IGF.Builder.CreateBitCast(result, IGF.IGM.TypeMetadataPtrTy);
return result;
}
}
llvm::Value *result = IGF.emitTypeMetadataRef(type);
if (desiredType == MetadataValueType::ObjCClass)
result = IGF.Builder.CreateBitCast(result, IGF.IGM.ObjCClassPtrTy);
return result;
}
/// Emit a metatype value for a known type.
void irgen::emitMetatypeRef(IRGenFunction &IGF, CanMetatypeType type,
Explosion &explosion) {
switch (type->getRepresentation()) {
case MetatypeRepresentation::Thin:
// Thin types have a trivial representation.
break;
case MetatypeRepresentation::Thick:
explosion.add(IGF.emitTypeMetadataRef(type.getInstanceType()));
break;
case MetatypeRepresentation::ObjC:
explosion.add(emitClassHeapMetadataRef(IGF, type.getInstanceType(),
MetadataValueType::ObjCClass));
break;
}
}
/*****************************************************************************/
/** 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 = [&] {
switch (cast<FuncDecl>(fn)->getAccessorKind()) {
case AccessorKind::NotAccessor:
return Flags::Kind::Method;
case AccessorKind::IsGetter:
return Flags::Kind::Getter;
case AccessorKind::IsSetter:
return Flags::Kind::Setter;
case AccessorKind::IsMaterializeForSet:
return Flags::Kind::MaterializeForSet;
case AccessorKind::IsWillSet:
case AccessorKind::IsDidSet:
case AccessorKind::IsAddressor:
case AccessorKind::IsMutableAddressor:
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 NominalTypeDescriptorBuilderBase {
protected:
Impl &asImpl() { return *static_cast<Impl*>(this); }
IRGenModule &IGM;
private:
ConstantInitBuilder InitBuilder;
protected:
ConstantStructBuilder B;
NominalTypeDescriptorBuilderBase(IRGenModule &IGM)
: IGM(IGM), InitBuilder(IGM), B(InitBuilder.beginStruct()) {
B.setPacked(true);
}
public:
void layout() {
asImpl().addName();
asImpl().addKindDependentFields();
asImpl().addGenericMetadataPatternAndKind();
asImpl().addAccessFunction();
asImpl().addGenericParams();
}
CanType getAbstractType() {
return asImpl().getTarget()->getDeclaredType()->getCanonicalType();
}
void addName() {
B.addRelativeAddress(getMangledTypeName(IGM, getAbstractType(),
/*willBeRelativelyAddressed*/ true));
}
void addGenericMetadataPatternAndKind() {
NominalTypeDecl *ntd = asImpl().getTarget();
auto kind = asImpl().getKind();
if (!ntd->isGenericContext()) {
// There's no pattern to link.
B.addInt32(kind);
return;
}
B.addTaggedRelativeOffset(
IGM.RelativeAddressTy,
IGM.getAddrOfTypeMetadata(getAbstractType(), /*pattern*/ true),
kind);
}
void addAccessFunction() {
NominalTypeDecl *typeDecl = asImpl().getTarget();
llvm::Constant *accessFn =
getRequiredTypeMetadataAccessFunction(IGM, typeDecl, NotForDefinition);
B.addRelativeAddressOrNull(accessFn);
}
void addGenericParams() {
NominalTypeDecl *ntd = asImpl().getTarget();
// uint32_t GenericParameterVectorOffset;
B.addInt32(asImpl().getGenericParamsOffset() / IGM.getPointerSize());
// The archetype order here needs to be consistent with
// MetadataVisitor::addGenericFields.
GenericTypeRequirements requirements(IGM, ntd);
// uint32_t NumGenericRequirements;
B.addInt32(requirements.getStorageSizeInWords());
// uint32_t NumPrimaryGenericParameters;
B.addInt32(requirements.getNumTypeRequirements());
// GenericParameterDescriptorFlags Flags;
GenericParameterDescriptorFlags flags;
if (ntd->getDeclContext()->isTypeContext())
flags = flags.withHasParent(true);
if (requirements.hasParentType())
flags = flags.withHasGenericParent(true);
if (auto *cd = dyn_cast<ClassDecl>(ntd)) {
auto &layout = IGM.getMetadataLayout(cd);
if (layout.getVTableSize() > 0)
flags = flags.withHasVTable(true);
}
B.addInt32(flags.getIntValue());
// TODO: provide reflective descriptions of the type and
// conformance requirements stored here.
// };
}
llvm::Constant *emit() {
asImpl().layout();
auto addr = IGM.getAddrOfNominalTypeDescriptor(asImpl().getTarget(),
B.finishAndCreateFuture());
auto var = cast<llvm::GlobalVariable>(addr);
var->setConstant(true);
IGM.setTrueConstGlobal(var);
return var;
}
// Derived class must provide:
// NominalTypeDecl *getTarget();
// unsigned getKind();
// unsigned getGenericParamsOffset();
// void addKindDependentFields();
};
/// Build a doubly-null-terminated list of field names.
template<typename ValueDeclRange>
unsigned getFieldNameString(const ValueDeclRange &fields,
llvm::SmallVectorImpl<char> &out) {
unsigned numFields = 0;
{
llvm::raw_svector_ostream os(out);
for (ValueDecl *prop : fields) {
os << prop->getBaseName() << '\0';
++numFields;
}
// The final null terminator is provided by getAddrOfGlobalString.
}
return numFields;
}
/// Build the field type vector accessor for a nominal type. This is a
/// function that lazily instantiates the type metadata for all of the
/// types of the stored properties of an instance of a nominal type.
static llvm::Function *
getFieldTypeAccessorFn(IRGenModule &IGM,
NominalTypeDecl *type,
ArrayRef<FieldTypeInfo> fieldTypes) {
// The accessor function has the following signature:
// const Metadata * const *(*GetFieldTypes)(const Metadata *T);
auto metadataArrayPtrTy = IGM.TypeMetadataPtrTy->getPointerTo();
auto fnTy = llvm::FunctionType::get(metadataArrayPtrTy,
IGM.TypeMetadataPtrTy,
/*vararg*/ false);
auto fn = llvm::Function::Create(fnTy, llvm::GlobalValue::PrivateLinkage,
llvm::Twine("get_field_types_")
+ type->getName().str(),
IGM.getModule());
fn->setAttributes(IGM.constructInitialAttributes());
// Emit the body of the field type accessor later. We need to access
// the type metadata for the fields, which could lead to infinite recursion
// in recursive types if we build the field type accessor during metadata
// generation.
IGM.addLazyFieldTypeAccessor(type, fieldTypes, fn);
return fn;
}
/// Build a field type accessor for stored properties.
static llvm::Function *
getFieldTypeAccessorFn(IRGenModule &IGM,
NominalTypeDecl *type,
NominalTypeDecl::StoredPropertyRange storedProperties){
SmallVector<FieldTypeInfo, 4> types;
for (VarDecl *prop : storedProperties) {
auto propertyType = type->mapTypeIntoContext(prop->getInterfaceType())
->getCanonicalType();
types.push_back(FieldTypeInfo(propertyType,
/*indirect*/ false,
propertyType->is<WeakStorageType>()));
}
return getFieldTypeAccessorFn(IGM, type, types);
}
/// Build a case type accessor for enum payloads.
static llvm::Function *
getFieldTypeAccessorFn(IRGenModule &IGM,
NominalTypeDecl *type,
ArrayRef<EnumImplStrategy::Element> enumElements) {
SmallVector<FieldTypeInfo, 4> types;
// This is a terrible special case, but otherwise the archetypes
// aren't mapped correctly because the EnumImplStrategy ends up
// using the lowered cases, i.e. the cases for Optional<>.
if (type->classifyAsOptionalType() == OTK_ImplicitlyUnwrappedOptional) {
assert(enumElements.size() == 1);
auto decl = IGM.Context.getImplicitlyUnwrappedOptionalSomeDecl();
auto caseType = decl->getParentEnum()->mapTypeIntoContext(
decl->getArgumentInterfaceType())
->getCanonicalType();
types.push_back(FieldTypeInfo(caseType, false, false));
return getFieldTypeAccessorFn(IGM, type, types);
}
for (auto &elt : enumElements) {
auto caseType = elt.decl->getParentEnum()->mapTypeIntoContext(
elt.decl->getArgumentInterfaceType())
->getCanonicalType();
bool isIndirect = elt.decl->isIndirect()
|| elt.decl->getParentEnum()->isIndirect();
types.push_back(FieldTypeInfo(caseType, isIndirect, /*weak*/ false));
}
return getFieldTypeAccessorFn(IGM, type, types);
}
class StructNominalTypeDescriptorBuilder
: public NominalTypeDescriptorBuilderBase<StructNominalTypeDescriptorBuilder>
{
using super
= NominalTypeDescriptorBuilderBase<StructNominalTypeDescriptorBuilder>;
// Offsets of key fields in the metadata records.
Size FieldVectorOffset, GenericParamsOffset;
StructDecl *Target;
public:
StructNominalTypeDescriptorBuilder(IRGenModule &IGM,
StructDecl *s)
: super(IGM), Target(s)
{
auto &layout = IGM.getMetadataLayout(Target);
FieldVectorOffset = layout.getFieldOffsetVectorOffset().getStatic();
GenericParamsOffset = layout.getStaticGenericRequirementsOffset();
}
StructDecl *getTarget() { return Target; }
unsigned getKind() {
return unsigned(NominalTypeKind::Struct);
}
Size getGenericParamsOffset() {
return GenericParamsOffset;
}
void addKindDependentFields() {
// Build the field name list.
llvm::SmallString<64> fieldNames;
unsigned numFields = getFieldNameString(Target->getStoredProperties(),
fieldNames);
B.addInt32(numFields);
B.addInt32(FieldVectorOffset / IGM.getPointerSize());
B.addRelativeAddress(IGM.getAddrOfGlobalString(fieldNames,
/*willBeRelativelyAddressed*/ true));
// Build the field type accessor function.
llvm::Function *fieldTypeVectorAccessor
= getFieldTypeAccessorFn(IGM, Target,
Target->getStoredProperties());
B.addRelativeAddress(fieldTypeVectorAccessor);
}
};
class ClassNominalTypeDescriptorBuilder
: public NominalTypeDescriptorBuilderBase<ClassNominalTypeDescriptorBuilder>,
public SILVTableVisitor<ClassNominalTypeDescriptorBuilder>
{
using super
= NominalTypeDescriptorBuilderBase<ClassNominalTypeDescriptorBuilder>;
// Offsets of key fields in the metadata records.
Size FieldVectorOffset, GenericParamsOffset;
SILVTable *VTable;
Size VTableOffset;
unsigned VTableSize;
ClassDecl *Target;
public:
ClassNominalTypeDescriptorBuilder(IRGenModule &IGM,
ClassDecl *c)
: super(IGM),
SILVTableVisitor<ClassNominalTypeDescriptorBuilder>(IGM.getSILTypes()),
Target(c)
{
auto &layout = IGM.getMetadataLayout(Target);
FieldVectorOffset = layout.getStaticFieldOffsetVectorOffset();
GenericParamsOffset = layout.getStaticGenericRequirementsOffset();
VTable = IGM.getSILModule().lookUpVTable(Target);
VTableOffset = layout.getStaticVTableOffset();
VTableSize = layout.getVTableSize();
}
ClassDecl *getTarget() { return Target; }
unsigned getKind() {
return unsigned(NominalTypeKind::Class);
}
Size getGenericParamsOffset() {
return GenericParamsOffset;
}
void addKindDependentFields() {
// Build the field name list.
llvm::SmallString<64> fieldNames;
unsigned numFields = getFieldNameString(Target->getStoredProperties(),
fieldNames);
B.addInt32(numFields);
B.addInt32(FieldVectorOffset / IGM.getPointerSize());
B.addRelativeAddress(IGM.getAddrOfGlobalString(fieldNames,
/*willBeRelativelyAddressed*/ true));
// Build the field type accessor function.
llvm::Function *fieldTypeVectorAccessor
= getFieldTypeAccessorFn(IGM, Target,
Target->getStoredProperties());
B.addRelativeAddress(fieldTypeVectorAccessor);
}
void addVTableDescriptor() {
assert(VTableSize != 0);
B.addInt32(VTableOffset / IGM.getPointerSize());
B.addInt32(VTableSize);
if (doesClassMetadataRequireDynamicInitialization(IGM, Target))
addVTableEntries(Target);
// TODO: Emit reflection metadata for virtual methods
}
void addMethod(SILDeclRef fn) {
assert(VTable && "no vtable?!");
auto descriptor = B.beginStruct(IGM.MethodDescriptorStructTy);
// Classify the method.
using Flags = MethodDescriptorFlags;
auto flags = getMethodDescriptorFlags<Flags>(fn.getDecl());
// Remember if the declaration was dynamic.
if (fn.getDecl()->isDynamic())
flags = flags.withIsDynamic(true);
// TODO: final? open?
auto *dc = fn.getDecl()->getDeclContext();
assert(!isa<ExtensionDecl>(dc));
if (fn.getDecl()->getDeclContext() == Target) {
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.addInt(IGM.Int32Ty, flags.getIntValue());
descriptor.finishAndAddTo(B);
}
void addMethodOverride(SILDeclRef baseRef, SILDeclRef declRef) {}
void addPlaceholder(MissingMemberDecl *MMD) {
llvm_unreachable("cannot generate metadata with placeholders in it");
}
void layout() {
super::layout();
if (VTableSize != 0)
addVTableDescriptor();
}
};
class EnumNominalTypeDescriptorBuilder
: public NominalTypeDescriptorBuilderBase<EnumNominalTypeDescriptorBuilder>
{
using super
= NominalTypeDescriptorBuilderBase<EnumNominalTypeDescriptorBuilder>;
// Offsets of key fields in the metadata records.
Size GenericParamsOffset;
Size PayloadSizeOffset;
EnumDecl *Target;
public:
EnumNominalTypeDescriptorBuilder(IRGenModule &IGM, EnumDecl *c)
: super(IGM), Target(c)
{
auto &layout = IGM.getMetadataLayout(Target);
GenericParamsOffset = layout.getStaticGenericRequirementsOffset();
if (layout.hasPayloadSizeOffset())
PayloadSizeOffset = layout.getPayloadSizeOffset().getStatic();
}
EnumDecl *getTarget() { return Target; }
unsigned getKind() {
return unsigned(NominalTypeKind::Enum);
}
Size getGenericParamsOffset() {
return GenericParamsOffset;
}
void addKindDependentFields() {
auto &strategy = getEnumImplStrategy(IGM,
Target->getDeclaredTypeInContext()->getCanonicalType());
// # 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");
B.addInt32(numPayloads | (PayloadSizeOffsetInWords << 24));
// # empty cases
B.addInt32(strategy.getElementsWithNoPayload().size());
B.addRelativeAddressOrNull(strategy.emitCaseNames());
// Build the case type accessor.
llvm::Function *caseTypeVectorAccessor
= getFieldTypeAccessorFn(IGM, Target,
strategy.getElementsWithPayload());
B.addRelativeAddress(caseTypeVectorAccessor);
}
};
} // end anonymous namespace
void
IRGenModule::addLazyFieldTypeAccessor(NominalTypeDecl *type,
ArrayRef<FieldTypeInfo> fieldTypes,
llvm::Function *fn) {
IRGen.addLazyFieldTypeAccessor(type, fieldTypes, fn, this);
}
void
irgen::emitFieldTypeAccessor(IRGenModule &IGM,
NominalTypeDecl *type,
llvm::Function *fn,
ArrayRef<FieldTypeInfo> fieldTypes)
{
IRGenFunction IGF(IGM, fn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, fn);
auto metadataArrayPtrTy = IGM.TypeMetadataPtrTy->getPointerTo();
CanType formalType = type->getDeclaredTypeInContext()->getCanonicalType();
llvm::Value *metadata = IGF.collectParameters().claimNext();
setTypeMetadataName(IGM, metadata, formalType);
// Get the address at which the field type vector reference should be
// cached.
llvm::Value *vectorPtr;
auto nullVector = llvm::ConstantPointerNull::get(metadataArrayPtrTy);
// If the type is not generic, we can use a global variable to cache the
// address of the field type vector for the single instance.
if (!type->isGenericContext()) {
vectorPtr = new llvm::GlobalVariable(*IGM.getModule(),
metadataArrayPtrTy,
/*constant*/ false,
llvm::GlobalValue::PrivateLinkage,
nullVector,
llvm::Twine("field_type_vector_")
+ type->getName().str());
// For a generic type, use a slot we saved in the generic metadata pattern
// immediately after the metadata object itself, which should be
// instantiated with every generic metadata instance.
} else {
auto size = IGM.getMetadataLayout(type).getSize();
Size offset = size.getOffsetToEnd();
vectorPtr = IGF.Builder.CreateBitCast(metadata,
metadataArrayPtrTy->getPointerTo());
vectorPtr = IGF.Builder.CreateConstInBoundsGEP1_32(
/*Ty=*/nullptr, vectorPtr, IGM.getOffsetInWords(offset));
}
// First, see if the field type vector has already been populated. This
// load can be nonatomic; if we race to build the field offset vector, we
// will detect so when we try to commit our pointer and simply discard the
// redundant work.
llvm::Value *initialVector
= IGF.Builder.CreateLoad(vectorPtr, IGM.getPointerAlignment());
auto entryBB = IGF.Builder.GetInsertBlock();
auto buildBB = IGF.createBasicBlock("build_field_types");
auto raceLostBB = IGF.createBasicBlock("race_lost");
auto doneBB = IGF.createBasicBlock("done");
llvm::Value *isNull
= IGF.Builder.CreateICmpEQ(initialVector, nullVector);
IGF.Builder.CreateCondBr(isNull, buildBB, doneBB);
// Build the field type vector if we didn't already.
IGF.Builder.emitBlock(buildBB);
// Bind the metadata instance to our local type data so we
// use it to provide metadata for generic parameters in field types.
IGF.bindLocalTypeDataFromTypeMetadata(formalType, IsExact, metadata);
// Allocate storage for the field vector.
unsigned allocSize = fieldTypes.size() * IGM.getPointerSize().getValue();
auto allocSizeVal = llvm::ConstantInt::get(IGM.IntPtrTy, allocSize);
auto allocAlignMaskVal =
IGM.getSize(IGM.getPointerAlignment().asSize() - Size(1));
llvm::Value *builtVectorAlloc
= IGF.emitAllocRawCall(allocSizeVal, allocAlignMaskVal);
llvm::Value *builtVector
= IGF.Builder.CreateBitCast(builtVectorAlloc, metadataArrayPtrTy);
// Emit type metadata for the fields into the vector.
for (unsigned i : indices(fieldTypes)) {
auto fieldTy = fieldTypes[i].getType();
auto slot = IGF.Builder.CreateInBoundsGEP(builtVector,
llvm::ConstantInt::get(IGM.Int32Ty, i));
// Strip reference storage qualifiers like unowned and weak.
// FIXME: Some clients probably care about them.
if (auto refStorTy = dyn_cast<ReferenceStorageType>(fieldTy))
fieldTy = refStorTy.getReferentType();
auto metadata = IGF.emitTypeMetadataRef(fieldTy);
auto fieldTypeInfo = fieldTypes[i];
// Mix in flag bits.
if (fieldTypeInfo.hasFlags()) {
auto flags = FieldType()
.withIndirect(fieldTypeInfo.isIndirect())
.withWeak(fieldTypeInfo.isWeak());
auto metadataBits = IGF.Builder.CreatePtrToInt(metadata, IGF.IGM.SizeTy);
metadataBits = IGF.Builder.CreateOr(metadataBits,
llvm::ConstantInt::get(IGF.IGM.SizeTy, flags.getIntValue()));
metadata = IGF.Builder.CreateIntToPtr(metadataBits, metadata->getType());
}
IGF.Builder.CreateStore(metadata, slot, IGM.getPointerAlignment());
}
// Atomically compare-exchange a pointer to our vector into the slot.
auto vectorIntPtr = IGF.Builder.CreateBitCast(vectorPtr,
IGM.IntPtrTy->getPointerTo());
auto builtVectorInt = IGF.Builder.CreatePtrToInt(builtVector,
IGM.IntPtrTy);
auto zero = llvm::ConstantInt::get(IGM.IntPtrTy, 0);
llvm::Value *raceVectorInt = IGF.Builder.CreateAtomicCmpXchg(vectorIntPtr,
zero, builtVectorInt,
llvm::AtomicOrdering::SequentiallyConsistent,
llvm::AtomicOrdering::SequentiallyConsistent);
// We might have added internal control flow above.
buildBB = IGF.Builder.GetInsertBlock();
// The pointer in the slot should still have been null.
auto didStore = IGF.Builder.CreateExtractValue(raceVectorInt, 1);
raceVectorInt = IGF.Builder.CreateExtractValue(raceVectorInt, 0);
IGF.Builder.CreateCondBr(didStore, doneBB, raceLostBB);
// If the cmpxchg failed, someone beat us to landing their field type
// vector. Deallocate ours and return the winner.
IGF.Builder.emitBlock(raceLostBB);
IGF.emitDeallocRawCall(builtVectorAlloc, allocSizeVal, allocAlignMaskVal);
auto raceVector = IGF.Builder.CreateIntToPtr(raceVectorInt,
metadataArrayPtrTy);
IGF.Builder.CreateBr(doneBB);
// Return the result.
IGF.Builder.emitBlock(doneBB);
auto phi = IGF.Builder.CreatePHI(metadataArrayPtrTy, 3);
phi->addIncoming(initialVector, entryBB);
phi->addIncoming(builtVector, buildBB);
phi->addIncoming(raceVector, raceLostBB);
IGF.Builder.CreateRet(phi);
}
/*****************************************************************************/
/** Metadata Emission ********************************************************/
/*****************************************************************************/
namespace {
/// An adapter class which turns a metadata layout class into a
/// generic metadata layout class.
template <class Impl, class Base>
class GenericMetadataBuilderBase : public Base {
typedef Base super;
/// The number of generic witnesses in the type we're emitting.
/// This is not really something we need to track.
unsigned NumGenericWitnesses = 0;
struct FillOp {
CanType Type;
Optional<ProtocolConformanceRef> Conformance;
Size ToOffset;
bool IsRelative;
};
SmallVector<FillOp, 8> FillOps;
enum { TemplateHeaderFieldCount = 5 };
enum { NumPrivateDataWords = swift::NumGenericMetadataPrivateDataWords };
protected:
Size TemplateHeaderSize;
/// The offset of the address point in the type we're emitting.
Size AddressPoint = Size::invalid();
IRGenModule &IGM = super::IGM;
using super::asImpl;
using super::Target;
using super::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. If true, the value witness will be
/// tail-emplaced inside the metadata pattern and initialized by the fill
/// function. Implies HasDependentMetadata.
bool HasDependentVWT = false;
/// The offset of the tail-allocated dependent VWT, if any.
Size DependentVWTPoint = Size::invalid();
template <class... T>
GenericMetadataBuilderBase(IRGenModule &IGM, T &&...args)
: super(IGM, std::forward<T>(args)...) {}
/// Emit the create function for the template.
llvm::Function *emitCreateFunction() {
// Metadata *(*CreateFunction)(GenericMetadata*, const void * const *)
llvm::Type *argTys[] = {IGM.TypeMetadataPatternPtrTy, IGM.Int8PtrPtrTy};
auto ty = llvm::FunctionType::get(IGM.TypeMetadataPtrTy,
argTys, /*isVarArg*/ false);
llvm::Function *f = llvm::Function::Create(ty,
llvm::GlobalValue::PrivateLinkage,
llvm::Twine("create_generic_metadata_")
+ Target->getName().str(),
&IGM.Module);
f->setAttributes(IGM.constructInitialAttributes());
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 *metadataPattern = params.claimNext();
llvm::Value *args = params.claimNext();
// Bind the generic arguments.
if (Target->isGenericContext()) {
Address argsArray(args, IGM.getPointerAlignment());
emitPolymorphicParametersFromArray(IGF, Target, argsArray);
}
// Allocate the metadata.
llvm::Value *metadataValue =
asImpl().emitAllocateMetadata(IGF, metadataPattern, args);
// Execute the fill ops. Cast the parameters to word pointers because the
// fill indexes are word-indexed.
Address metadataWords(IGF.Builder.CreateBitCast(metadataValue, IGM.Int8PtrPtrTy),
IGM.getPointerAlignment());
for (auto &fillOp : FillOps) {
llvm::Value *value;
if (fillOp.Conformance) {
value = emitWitnessTableRef(IGF, fillOp.Type, *fillOp.Conformance);
} else {
value = IGF.emitTypeMetadataRef(fillOp.Type);
}
auto dest = createPointerSizedGEP(IGF, metadataWords,
fillOp.ToOffset - AddressPoint);
// A far relative indirectable pointer.
if (fillOp.IsRelative) {
dest = IGF.Builder.CreateElementBitCast(dest,
IGM.FarRelativeAddressTy);
IGF.emitStoreOfRelativeIndirectablePointer(value, dest,
/*isFar*/ true);
// A direct pointer.
} else {
value = IGF.Builder.CreateBitCast(value, IGM.Int8PtrTy);
IGF.Builder.CreateStore(value, dest);
}
}
// Initialize the instantiated dependent value witness table, if we have
// one.
llvm::Value *vwtableValue = nullptr;
if (HasDependentVWT) {
assert(!AddressPoint.isInvalid() && "did not set valid address point!");
assert(!DependentVWTPoint.isInvalid() && "did not set dependent VWT point!");
// Fill in the pointer from the metadata to the VWT. The VWT pointer
// always immediately precedes the address point.
auto vwtAddr = createPointerSizedGEP(IGF, metadataWords,
DependentVWTPoint - AddressPoint);
vwtableValue = IGF.Builder.CreateBitCast(vwtAddr.getAddress(),
IGF.IGM.WitnessTablePtrTy);
auto vwtAddrVal = IGF.Builder.CreateBitCast(vwtableValue, IGM.Int8PtrTy);
auto vwtRefAddr = createPointerSizedGEP(IGF, metadataWords,
Size(0) - IGM.getPointerSize());
IGF.Builder.CreateStore(vwtAddrVal, vwtRefAddr);
HasDependentMetadata = true;
}
if (HasDependentMetadata) {
asImpl().emitInitializeMetadata(IGF, metadataValue, vwtableValue);
}
// The metadata is now complete.
IGF.Builder.CreateRet(metadataValue);
return f;
}
void addFillOp(CanType type, Optional<ProtocolConformanceRef> conf,
bool isRelative) {
FillOps.push_back({type, conf, getNextOffsetFromTemplateHeader(),
isRelative });
}
public:
void createMetadataAccessFunction() {
(void) getGenericTypeMetadataAccessFunction(IGM, Target, ForDefinition);
}
void layout() {
TemplateHeaderSize =
((NumPrivateDataWords + 1) * IGM.getPointerSize()) + Size(8);
auto privateDataInit = getPrivateDataInit();
// Leave room for the header.
auto createFunctionField = B.addPlaceholderWithSize(IGM.Int8PtrTy);
auto sizeField = B.addPlaceholderWithSize(IGM.Int32Ty);
auto numArgumentsField = B.addPlaceholderWithSize(IGM.Int16Ty);
auto addressPointField = B.addPlaceholderWithSize(IGM.Int16Ty);
auto privateDataField =
B.addPlaceholderWithSize(privateDataInit->getType());
// Lay out the template data.
super::layout();
// Save a slot for the field type vector address to be instantiated into.
asImpl().addFieldTypeVectorReferenceSlot();
// If we have a dependent value witness table, emit its template.
if (HasDependentVWT) {
// Note the dependent VWT offset.
DependentVWTPoint = getNextOffsetFromTemplateHeader();
asImpl().addDependentValueWitnessTablePattern();
}
asImpl().addDependentData();
// Fill in the header:
// Metadata *(*CreateFunction)(GenericMetadata *, const void*);
B.fillPlaceholder(createFunctionField, emitCreateFunction());
// uint32_t MetadataSize;
// We compute this assuming that every entry in the metadata table
// is a pointer in size.
Size size = getNextOffsetFromTemplateHeader();
B.fillPlaceholderWithInt(sizeField, IGM.Int32Ty, size.getValue());
// uint16_t NumArguments;
// TODO: ultimately, this should be the number of actual template
// arguments, not the number of witness tables required.
unsigned numGenericArguments =
GenericArguments::getNumGenericArguments(IGM, Target);
B.fillPlaceholderWithInt(numArgumentsField,
IGM.Int16Ty, numGenericArguments);
// uint16_t AddressPoint;
assert(!AddressPoint.isInvalid() && "address point not noted!");
B.fillPlaceholderWithInt(addressPointField,
IGM.Int16Ty, AddressPoint.getValue());
// void *PrivateData[NumPrivateDataWords];
B.fillPlaceholder(privateDataField, privateDataInit);
}
/// Write down the index of the address point.
void noteAddressPoint() {
AddressPoint = getNextOffsetFromTemplateHeader();
super::noteAddressPoint();
}
/// Ignore the preallocated header.
Size getNextOffsetFromTemplateHeader() const {
// Note that the header fields are all pointer-sized.
return B.getNextOffsetFromGlobal() - TemplateHeaderSize;
}
/// Ignore the destructor and value witness table.
Size getNextOffsetFromAddressPoint() const {
return getNextOffsetFromTemplateHeader() - AddressPoint;
}
template <class... T>
void addGenericArgument(CanType type, T &&...args) {
NumGenericWitnesses++;
addFillOp(type, None, /*relative*/ false);
super::addGenericArgument(type, std::forward<T>(args)...);
}
template <class... T>
void addGenericWitnessTable(CanType type, ProtocolConformanceRef conf,
T &&...args) {
NumGenericWitnesses++;
addFillOp(type, conf, /*relative*/ false);
super::addGenericWitnessTable(type, conf, std::forward<T>(args)...);
}
void addFieldTypeVectorReferenceSlot() {
B.addNullPointer(IGM.TypeMetadataPtrTy->getPointerTo());
}
// Can be overridden by subclassers to emit other dependent metadata.
void addDependentData() {}
private:
static llvm::Constant *makeArray(llvm::Type *eltTy,
ArrayRef<llvm::Constant*> elts) {
auto arrayTy = llvm::ArrayType::get(eltTy, elts.size());
return llvm::ConstantArray::get(arrayTy, elts);
}
/// Produce the initializer for the private-data field of the
/// template header.
llvm::Constant *getPrivateDataInit() {
auto null = llvm::ConstantPointerNull::get(IGM.Int8PtrTy);
llvm::Constant *privateData[NumPrivateDataWords];
for (auto &element : privateData)
element = null;
return makeArray(IGM.Int8PtrTy, privateData);
}
};
} // end anonymous namespace
llvm::Value *
irgen::emitInitializeFieldOffsetVector(IRGenFunction &IGF,
SILType T,
llvm::Value *metadata,
llvm::Value *vwtable) {
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(IGF.IGM.Int8PtrPtrTy,
storedProperties.size()),
IGF.IGM.getPointerAlignment(), "classFields");
IGF.Builder.CreateLifetimeStart(fields,
IGF.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 = IGF.emitTypeLayoutRef(propTy);
Address field = IGF.Builder.CreateConstArrayGEP(fields, index,
IGF.IGM.getPointerSize());
IGF.Builder.CreateStore(metadata, field);
++index;
}
// Ask the runtime to lay out the class. This can relocate it if it
// wasn't allocated with swift_allocateGenericClassMetadata.
auto numFields = IGF.IGM.getSize(Size(storedProperties.size()));
if (isa<ClassDecl>(target)) {
assert(vwtable == nullptr);
metadata = IGF.Builder.CreateCall(IGF.IGM.getInitClassMetadataUniversalFn(),
{metadata, numFields,
fields.getAddress(), fieldVector});
} else {
assert(isa<StructDecl>(target));
IGF.Builder.CreateCall(IGF.IGM.getInitStructMetadataUniversalFn(),
{numFields, fields.getAddress(),
fieldVector, vwtable});
}
IGF.Builder.CreateLifetimeEnd(fields,
IGF.IGM.getPointerSize() * storedProperties.size());
return metadata;
}
// Classes
namespace {
/// An adapter for laying out class metadata.
template <class Impl>
class ClassMetadataBuilderBase : public ClassMetadataVisitor<Impl> {
using super = ClassMetadataVisitor<Impl>;
protected:
using super::IGM;
using super::Target;
using super::asImpl;
ConstantStructBuilder &B;
const StructLayout &Layout;
const ClassLayout &FieldLayout;
SILVTable *VTable;
struct MethodOverride {
Size Offset;
SILFunction *Method;
};
SmallVector<MethodOverride, 4> Overrides;
ClassMetadataBuilderBase(IRGenModule &IGM, ClassDecl *theClass,
ConstantStructBuilder &builder,
const StructLayout &layout,
const ClassLayout &fieldLayout)
: super(IGM, theClass), B(builder),
Layout(layout), FieldLayout(fieldLayout) {
VTable = IGM.getSILModule().lookUpVTable(Target);
}
public:
/// 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));
}
}
/// The runtime provides a value witness table for Builtin.NativeObject.
void addValueWitnessTable() {
ClassDecl *cls = Target;
auto type = (cls->checkObjCAncestry() != ObjCClassKind::NonObjC
? IGM.Context.TheUnknownObjectType
: IGM.Context.TheNativeObjectType);
auto wtable = IGM.getAddrOfValueWitnessTable(type);
B.add(wtable);
}
void addDestructorFunction() {
auto expansion = ResilienceExpansion::Minimal;
auto dtorRef = SILDeclRef(Target->getDestructor(),
SILDeclRef::Kind::Deallocator,
expansion);
SILFunction *dtorFunc = IGM.getSILModule().lookUpFunction(dtorRef);
if (dtorFunc) {
B.add(IGM.getAddrOfSILFunction(dtorFunc, NotForDefinition));
} else {
// In case the optimizer removed the function. See comment in
// addMethod().
B.addNullPointer(IGM.FunctionPtrTy);
}
}
void addNominalTypeDescriptor() {
auto descriptor =
ClassNominalTypeDescriptorBuilder(IGM, Target).emit();
B.addFarRelativeAddress(descriptor);
}
void addIVarDestroyer() {
auto dtorFunc = IGM.getAddrOfIVarInitDestroy(Target,
/*isDestroyer=*/ true,
/*isForeign=*/ false,
NotForDefinition);
if (dtorFunc) {
B.add(*dtorFunc);
} else {
B.addNullPointer(IGM.FunctionPtrTy);
}
}
bool addReferenceToHeapMetadata(CanType type, bool allowUninitialized) {
if (llvm::Constant *metadata
= tryEmitConstantHeapMetadataRef(IGM, type, allowUninitialized)) {
B.add(metadata);
return true;
} else {
// Leave a null pointer placeholder to be filled at runtime
B.addNullPointer(IGM.TypeMetadataPtrTy);
return false;
}
}
void addClassFlags() {
// Always set a flag saying that this is a Swift 1.0 class.
ClassFlags flags = ClassFlags::IsSwift1;
// Set a flag if the class uses Swift 1.0 refcounting.
auto type = Target->getDeclaredType()->getCanonicalType();
if (getReferenceCountingForType(IGM, type)
== ReferenceCounting::Native) {
flags |= ClassFlags::UsesSwift1Refcounting;
}
DeclAttributes attrs = Target->getAttrs();
if (auto objc = attrs.getAttribute<ObjCAttr>()) {
if (objc->getName())
flags |= ClassFlags::HasCustomObjCName;
}
if (attrs.hasAttribute<ObjCRuntimeNameAttr>())
flags |= ClassFlags::HasCustomObjCName;
B.addInt32((uint32_t) flags);
}
void addInstanceAddressPoint() {
// Right now, we never allocate fields before the address point.
B.addInt32(0);
}
void addInstanceSize() {
if (llvm::Constant *size
= tryEmitClassConstantFragileInstanceSize(IGM, Target)) {
// We only support a maximum 32-bit instance size.
if (IGM.SizeTy != IGM.Int32Ty)
size = llvm::ConstantExpr::getTrunc(size, IGM.Int32Ty);
B.add(size);
} else {
// Leave a zero placeholder to be filled at runtime
B.addInt32(0);
}
}
void addInstanceAlignMask() {
if (llvm::Constant *align
= tryEmitClassConstantFragileInstanceAlignMask(IGM, Target)) {
if (IGM.SizeTy != IGM.Int16Ty)
align = llvm::ConstantExpr::getTrunc(align, IGM.Int16Ty);
B.add(align);
} else {
// Leave a zero placeholder to be filled at runtime
B.addInt16(0);
}
}
void addRuntimeReservedBits() {
B.addInt16(0);
}
void addClassSize() {
auto size = IGM.getMetadataLayout(Target).getSize();
B.addInt32(size.FullSize.getValue());
}
void addClassAddressPoint() {
auto size = IGM.getMetadataLayout(Target).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.
B.addInt(IGM.IntPtrTy, 1);
return;
}
// Derive the RO-data.
llvm::Constant *data = emitClassPrivateData(IGM, Target);
// We always set the low bit to indicate this is a Swift class.
data = llvm::ConstantExpr::getPtrToInt(data, IGM.IntPtrTy);
data = llvm::ConstantExpr::getAdd(data,
llvm::ConstantInt::get(IGM.IntPtrTy, 1));
B.add(data);
}
void addFieldOffset(VarDecl *var) {
assert(var->hasStorage());
unsigned fieldIndex = FieldLayout.getFieldIndex(var);
llvm::Constant *fieldOffsetOrZero;
auto &element = Layout.getElement(fieldIndex);
if (element.getKind() == ElementLayout::Kind::Fixed) {
// 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));
}
B.add(fieldOffsetOrZero);
if (var->getDeclContext() == Target) {
auto access = FieldLayout.AllFieldAccesses[fieldIndex];
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(var, /*indirect*/ false,
ForDefinition);
auto offsetVar = cast<llvm::GlobalVariable>(offsetAddr.getAddress());
offsetVar->setInitializer(fieldOffsetOrZero);
// If we know the offset won't change, make it a constant.
offsetVar->setConstant(access == FieldAccess::ConstantDirect);
break;
}
case FieldAccess::ConstantIndirect:
// No global variable is needed.
break;
case FieldAccess::NonConstantIndirect:
// Emit a global variable storing an offset into the field offset
// vector within the class metadata. This access pattern is used
// when the field offset depends on generic parameters. As above,
// the Objective-C runtime will slide the field offsets within the
// class metadata to adjust for the superclass size.
//
// TODO: This isn't plumbed through all the way yet.
auto offsetAddr = IGM.getAddrOfFieldOffset(var, /*indirect*/ true,
ForDefinition);
auto offsetVar = cast<llvm::GlobalVariable>(offsetAddr.getAddress());
offsetVar->setConstant(false);
auto offset = getClassFieldOffsetOffset(IGM, Target, var).getValue();
auto offsetVal = llvm::ConstantInt::get(IGM.IntPtrTy, offset);
offsetVar->setInitializer(offsetVal);
break;
}
}
}
void addMethod(SILDeclRef fn) {
// Find the vtable entry.
assert(VTable && "no vtable?!");
auto entry = VTable->getEntry(IGM.getSILModule(), fn);
// If the class is resilient or generic, the runtime will construct the
// vtable for us. All we need to do is fix up overrides of superclass
// methods.
if (doesClassMetadataRequireDynamicInitialization(IGM, Target)) {
if (entry && entry->TheKind == SILVTable::Entry::Kind::Override) {
// Record the override so that we can fill it in later.
Overrides.push_back({asImpl().getNextOffsetFromAddressPoint(),
entry->Implementation});
}
B.addNullPointer(IGM.FunctionPtrTy);
return;
}
// 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 *) {
llvm_unreachable("cannot generate metadata with placeholders in it");
}
void addMethodOverride(SILDeclRef baseRef, SILDeclRef declRef) {}
void addGenericArgument(CanType argTy, ClassDecl *forClass) {
B.addNullPointer(IGM.TypeMetadataPtrTy);
}
void addGenericWitnessTable(CanType argTy, ProtocolConformanceRef conf,
ClassDecl *forClass) {
B.addNullPointer(IGM.WitnessTablePtrTy);
}
protected:
bool isFinishInitializationIdempotent() {
if (!Layout.isFixedLayout())
return false;
if (doesClassMetadataRequireDynamicInitialization(IGM, Target))
return false;
return true;
}
llvm::Value *emitFinishIdempotentInitialization(IRGenFunction &IGF,
llvm::Value *metadata) {
if (IGF.IGM.ObjCInterop) {
metadata =
IGF.Builder.CreateBitCast(metadata, IGF.IGM.ObjCClassPtrTy);
metadata =
IGF.Builder.CreateCall(IGF.IGM.getGetInitializedObjCClassFn(),
metadata);
metadata =
IGF.Builder.CreateBitCast(metadata, IGF.IGM.TypeMetadataPtrTy);
}
return metadata;
}
llvm::Value *emitFinishInitializationOfClassMetadata(IRGenFunction &IGF,
llvm::Value *metadata) {
// We assume that we've already filled in the class's generic arguments.
// We need to:
// - relocate the metadata to accommodate the superclass,
// if something in our hierarchy is resilient to us;
// - fill out the subclass's field offset vector, if its layout
// wasn't fixed;
// - copy field offsets and generic arguments from higher in the
// class hierarchy, if
// - copy the superclass data, if there are generic arguments
// or field offset vectors there that weren't filled in;
// - populate the field offset vector, if layout isn't fixed, and
// - register the class with the ObjC runtime, if ObjC interop is
// enabled.
//
// emitInitializeFieldOffsetVector will do everything in the full case.
if (doesClassMetadataRequireDynamicInitialization(IGF.IGM, Target)) {
auto classTy = Target->getDeclaredTypeInContext()->getCanonicalType();
auto loweredClassTy = IGF.IGM.getLoweredType(classTy);
metadata = emitInitializeFieldOffsetVector(IGF, loweredClassTy,
metadata,
/*vwtable=*/nullptr);
// TODO: do something intermediate when e.g. all we needed to do was
// set parent metadata pointers.
// Otherwise, all we need to do is register with the ObjC runtime.
} else {
metadata = emitFinishIdempotentInitialization(IGF, metadata);
assert(Overrides.empty());
}
emitInitializeMethodOverrides(IGF, metadata);
// 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 (!Layout.isFixedLayout() && !IGF.IGM.ObjCInterop)
emitInitializeFieldOffsets(IGF, metadata);
return metadata;
}
// Update vtable entries for method overrides. The runtime copies in
// the vtable from the superclass for us; we have to install method
// overrides ourselves.
void emitInitializeMethodOverrides(IRGenFunction &IGF,
llvm::Value *metadata) {
if (Overrides.empty())
return;
Address metadataWords(
IGF.Builder.CreateBitCast(metadata, IGM.Int8PtrPtrTy),
IGM.getPointerAlignment());
for (auto Override : Overrides) {
auto *implFn = IGM.getAddrOfSILFunction(Override.Method,
NotForDefinition);
auto dest = createPointerSizedGEP(IGF, metadataWords,
Override.Offset);
auto *value = IGF.Builder.CreateBitCast(implFn, IGM.Int8PtrTy);
IGF.Builder.CreateStore(value, dest);
}
}
// The Objective-C runtime will copy field offsets from the field offset
// vector into field offset globals for us, if present. If there's no
// Objective-C runtime, we have to do this ourselves.
void emitInitializeFieldOffsets(IRGenFunction &IGF,
llvm::Value *metadata) {
unsigned index = FieldLayout.InheritedStoredProperties.size();
for (auto prop : Target->getStoredProperties()) {
auto access = FieldLayout.AllFieldAccesses[index];
if (access == FieldAccess::NonConstantDirect) {
Address offsetA = IGF.IGM.getAddrOfFieldOffset(prop,
/*indirect*/ false,
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, Target, prop);
auto offsetVal = IGF.emitInvariantLoad(slot);
IGF.Builder.CreateStore(offsetVal, offsetA);
}
index++;
}
}
};
class ClassMetadataBuilder :
public ClassMetadataBuilderBase<ClassMetadataBuilder> {
using super = ClassMetadataBuilderBase<ClassMetadataBuilder>;
bool HasUnfilledSuperclass = false;
bool HasUnfilledParent = false;
Size AddressPoint;
public:
ClassMetadataBuilder(IRGenModule &IGM, ClassDecl *theClass,
ConstantStructBuilder &builder,
const StructLayout &layout,
const ClassLayout &fieldLayout)
: ClassMetadataBuilderBase(IGM, theClass, builder, layout, fieldLayout) {
}
void noteAddressPoint() {
super::noteAddressPoint();
AddressPoint = B.getNextOffsetFromGlobal();
}
Size getNextOffsetFromAddressPoint() const {
return B.getNextOffsetFromGlobal() - AddressPoint;
}
void addSuperClass() {
// 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 superclassTy = Target->mapTypeIntoContext(Target->getSuperclass());
if (!addReferenceToHeapMetadata(superclassTy->getCanonicalType(),
/*allowUninit*/ false)) {
HasUnfilledSuperclass = true;
}
}
void addParentMetadataRef(ClassDecl *forClass, Type classType) {
CanType parentType = classType->getCanonicalType().getNominalParent();
if (auto metadata =
tryEmitConstantTypeMetadataRef(IGM, parentType,
SymbolReferenceKind::Absolute)) {
B.add(metadata.getValue());
} else {
// Leave a null pointer placeholder to be filled by in-place
// initialization.
B.addNullPointer(IGM.TypeMetadataPtrTy);
if (forClass == Target)
HasUnfilledParent = true;
}
}
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 createMetadataAccessFunction() {
assert(!Target->isGenericContext());
auto type =cast<ClassType>(Target->getDeclaredType()->getCanonicalType());
(void) getTypeMetadataAccessFunction(IGM, type, ForDefinition,
[&](IRGenFunction &IGF, llvm::Constant *cacheVar) -> llvm::Value* {
// There's an interesting special case where we can do the
// initialization idempotently and thus avoid the need for a lock.
if (!HasUnfilledSuperclass && !HasUnfilledParent &&
isFinishInitializationIdempotent()) {
auto type = Target->getDeclaredType()->getCanonicalType();
auto metadata =
IGF.IGM.getAddrOfTypeMetadata(type, /*pattern*/ false);
return emitFinishIdempotentInitialization(IGF, metadata);
}
// Otherwise, use the generic path.
return emitInPlaceTypeMetadataAccessFunctionBody(IGF, type, cacheVar,
[&](IRGenFunction &IGF, llvm::Value *metadata) {
return emitInPlaceMetadataInitialization(IGF, type, metadata);
});
});
}
private:
llvm::Value *emitInPlaceMetadataInitialization(IRGenFunction &IGF,
CanClassType type,
llvm::Value *metadata) {
// Many of the things done by generic instantiation are unnecessary here:
// initializing the metaclass pointer
// initializing the ro-data pointer
// Initialize the superclass if we didn't do so as a constant.
if (HasUnfilledSuperclass) {
auto superclass = type->getSuperclass()->getCanonicalType();
llvm::Value *superclassMetadata =
emitClassHeapMetadataRef(IGF, superclass,
MetadataValueType::TypeMetadata,
/*allowUninit*/ false);
Address superField =
emitAddressOfSuperclassRefInClassMetadata(IGF, metadata);
superField = IGF.Builder.CreateElementBitCast(superField,
IGF.IGM.TypeMetadataPtrTy);
IGF.Builder.CreateStore(superclassMetadata, superField);
}
// Initialize the class's own parent pointer if it has one and it
// wasn't emitted as a constant.
if (HasUnfilledParent) {
auto parentType = type.getParent();
assert(parentType);
llvm::Value *parentMetadata = IGF.emitTypeMetadataRef(parentType);
auto parentSlot =
emitAddressOfParentMetadataSlot(IGF, metadata, type->getDecl());
IGF.Builder.CreateStore(parentMetadata, parentSlot);
}
metadata = emitFinishInitializationOfClassMetadata(IGF, metadata);
return metadata;
}
};
/// A builder for metadata templates.
class GenericClassMetadataBuilder :
public GenericMetadataBuilderBase<GenericClassMetadataBuilder,
ClassMetadataBuilderBase<GenericClassMetadataBuilder>>
{
typedef GenericMetadataBuilderBase super;
Size MetaclassPtrOffset = Size::invalid();
Size ClassRODataPtrOffset = Size::invalid();
Size MetaclassRODataPtrOffset = Size::invalid();
Size DependentMetaclassPoint = Size::invalid();
Size DependentClassRODataPoint = Size::invalid();
Size DependentMetaclassRODataPoint = Size::invalid();
public:
GenericClassMetadataBuilder(IRGenModule &IGM, ClassDecl *theClass,
ConstantStructBuilder &B,
const StructLayout &layout,
const ClassLayout &fieldLayout)
: super(IGM, theClass, B, layout, fieldLayout)
{
// We need special initialization of metadata objects to trick the ObjC
// runtime into initializing them.
HasDependentMetadata = true;
}
void addParentMetadataRef(ClassDecl *forClass, Type classType) {
CanType parentType = classType->getCanonicalType().getNominalParent();
this->addFillOp(parentType, None, /*relative*/ false);
B.addNullPointer(IGM.TypeMetadataPtrTy);
}
void addSuperClass() {
// Filled in by the runtime.
B.addNullPointer(IGM.TypeMetadataPtrTy);
}
llvm::Value *emitAllocateMetadata(IRGenFunction &IGF,
llvm::Value *metadataPattern,
llvm::Value *arguments) {
llvm::Value *superMetadata;
if (Target->hasSuperclass()) {
Type superclass = Target->getSuperclass();
superclass = Target->mapTypeIntoContext(superclass);
superMetadata =
emitClassHeapMetadataRef(IGF, superclass->getCanonicalType(),
MetadataValueType::ObjCClass);
} else if (IGM.ObjCInterop) {
superMetadata = emitObjCHeapMetadataRef(IGF,
IGM.getObjCRuntimeBaseForSwiftRootClass(Target));
} else {
superMetadata
= llvm::ConstantPointerNull::get(IGF.IGM.ObjCClassPtrTy);
}
return IGF.Builder.CreateCall(IGM.getAllocateGenericClassMetadataFn(),
{metadataPattern, arguments, superMetadata});
}
void addMetadataFlags() {
// The metaclass pointer will be instantiated here.
MetaclassPtrOffset = getNextOffsetFromTemplateHeader();
B.addInt(IGM.MetadataKindTy, 0);
}
void addClassDataPointer() {
// The rodata pointer will be instantiated here.
// Make sure we at least set the 'is Swift class' bit, though.
ClassRODataPtrOffset = getNextOffsetFromTemplateHeader();
B.addInt(IGM.MetadataKindTy, 1);
}
void addDependentData() {
if (!IGM.ObjCInterop) {
// Every piece of data in the dependent data appears to be related to
// Objective-C information. If we're not doing Objective-C interop, we
// can just skip adding it to the class.
return;
}
// Emit space for the dependent metaclass.
DependentMetaclassPoint = getNextOffsetFromTemplateHeader();
// 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
MetaclassRODataPtrOffset = getNextOffsetFromTemplateHeader();
B.addInt(IGM.IntPtrTy, 0);
std::tie(DependentClassRODataPoint, DependentMetaclassRODataPoint)
= emitClassPrivateDataFields(IGM, B, Target);
DependentClassRODataPoint -= TemplateHeaderSize;
DependentMetaclassRODataPoint -= TemplateHeaderSize;
}
void addDependentValueWitnessTablePattern() {
llvm_unreachable("classes should never have dependent vwtables");
}
void noteStartOfFieldOffsets(ClassDecl *whichClass) {
HasDependentMetadata = true;
}
void noteEndOfFieldOffsets(ClassDecl *whichClass) {}
// Suppress GenericMetadataBuilderBase's default behavior of introducing
// fill ops for generic arguments unless they belong directly to the target
// class and not its ancestors.
void addGenericArgument(CanType type, ClassDecl *forClass) {
if (forClass == Target) {
// Introduce the fill op.
GenericMetadataBuilderBase::addGenericArgument(type, forClass);
} else {
// Lay out the field, but don't fill it in, we will copy it from
// the superclass.
HasDependentMetadata = true;
ClassMetadataBuilderBase::addGenericArgument(type, forClass);
}
}
void addGenericWitnessTable(CanType type, ProtocolConformanceRef conf,
ClassDecl *forClass) {
if (forClass == Target) {
// Introduce the fill op.
GenericMetadataBuilderBase::addGenericWitnessTable(type, conf,forClass);
} else {
// Lay out the field, but don't provide the fill op, which we'll get
// from the superclass.
HasDependentMetadata = true;
ClassMetadataBuilderBase::addGenericWitnessTable(type, conf, forClass);
}
}
void emitInitializeMetadata(IRGenFunction &IGF,
llvm::Value *metadata,
llvm::Value *vwtable) {
assert(!HasDependentVWT && "class should never have dependent VWT");
// Fill in the metaclass pointer.
Address metadataPtr(IGF.Builder.CreateBitCast(metadata, IGF.IGM.Int8PtrPtrTy),
IGF.IGM.getPointerAlignment());
llvm::Value *metaclass;
if (IGF.IGM.ObjCInterop) {
assert(!DependentMetaclassPoint.isInvalid());
assert(!MetaclassPtrOffset.isInvalid());
Address metaclassPtrSlot = createPointerSizedGEP(IGF, metadataPtr,
MetaclassPtrOffset - AddressPoint);
metaclassPtrSlot = IGF.Builder.CreateBitCast(metaclassPtrSlot,
IGF.IGM.ObjCClassPtrTy->getPointerTo());
Address metaclassRawPtr = createPointerSizedGEP(IGF, metadataPtr,
DependentMetaclassPoint - AddressPoint);
metaclass = IGF.Builder.CreateBitCast(metaclassRawPtr,
IGF.IGM.ObjCClassPtrTy)
.getAddress();
IGF.Builder.CreateStore(metaclass, metaclassPtrSlot);
} else {
// FIXME: Remove altogether rather than injecting a NULL value.
// rdar://problem/18801263
assert(!MetaclassPtrOffset.isInvalid());
Address metaclassPtrSlot = createPointerSizedGEP(IGF, metadataPtr,
MetaclassPtrOffset - AddressPoint);
metaclassPtrSlot = IGF.Builder.CreateBitCast(metaclassPtrSlot,
IGF.IGM.ObjCClassPtrTy->getPointerTo());
IGF.Builder.CreateStore(
llvm::ConstantPointerNull::get(IGF.IGM.ObjCClassPtrTy),
metaclassPtrSlot);
}
// Fill in the rodata reference in the class.
Address classRODataPtr;
if (IGF.IGM.ObjCInterop) {
assert(!DependentClassRODataPoint.isInvalid());
assert(!ClassRODataPtrOffset.isInvalid());
Address rodataPtrSlot = createPointerSizedGEP(IGF, metadataPtr,
ClassRODataPtrOffset - AddressPoint);
rodataPtrSlot = IGF.Builder.CreateBitCast(rodataPtrSlot,
IGF.IGM.IntPtrTy->getPointerTo());
classRODataPtr = createPointerSizedGEP(IGF, metadataPtr,
DependentClassRODataPoint - AddressPoint);
// Set the low bit of the value to indicate "compiled by Swift".
llvm::Value *rodata = IGF.Builder.CreatePtrToInt(
classRODataPtr.getAddress(), IGF.IGM.IntPtrTy);
rodata = IGF.Builder.CreateOr(rodata, 1);
IGF.Builder.CreateStore(rodata, rodataPtrSlot);
} else {
// NOTE: Unlike other bits of the metadata that should later be removed,
// this one is important because things check this value's flags to
// determine what kind of object it is. That said, if those checks
// are determined to be removable, we can remove this as well per
// rdar://problem/18801263
assert(!ClassRODataPtrOffset.isInvalid());
Address rodataPtrSlot = createPointerSizedGEP(IGF, metadataPtr,
ClassRODataPtrOffset - AddressPoint);
rodataPtrSlot = IGF.Builder.CreateBitCast(rodataPtrSlot,
IGF.IGM.IntPtrTy->getPointerTo());
IGF.Builder.CreateStore(llvm::ConstantInt::get(IGF.IGM.IntPtrTy, 1),
rodataPtrSlot);
}
// Fill in the rodata reference in the metaclass.
Address metaclassRODataPtr;
if (IGF.IGM.ObjCInterop) {
assert(!DependentMetaclassRODataPoint.isInvalid());
assert(!MetaclassRODataPtrOffset.isInvalid());
Address rodataPtrSlot = createPointerSizedGEP(IGF, metadataPtr,
MetaclassRODataPtrOffset - AddressPoint);
rodataPtrSlot = IGF.Builder.CreateBitCast(rodataPtrSlot,
IGF.IGM.IntPtrTy->getPointerTo());
metaclassRODataPtr = createPointerSizedGEP(IGF, metadataPtr,
DependentMetaclassRODataPoint - AddressPoint);
llvm::Value *rodata = IGF.Builder.CreatePtrToInt(
metaclassRODataPtr.getAddress(), IGF.IGM.IntPtrTy);
IGF.Builder.CreateStore(rodata, rodataPtrSlot);
}
// We can assume that this never relocates the metadata because
// it should have been allocated properly for the class.
(void) emitFinishInitializationOfClassMetadata(IGF, metadata);
}
};
} // 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::GlobalValue *metadata) {
llvm::SmallString<32> classSymbol;
LinkEntity::forObjCClass(classDecl).mangle(classSymbol);
// Create the alias.
auto *metadataTy = cast<llvm::PointerType>(metadata->getType());
// Create the alias.
auto *alias = llvm::GlobalAlias::create(metadataTy->getElementType(),
metadataTy->getAddressSpace(),
metadata->getLinkage(),
classSymbol.str(), metadata,
IGM.getModule());
alias->setVisibility(metadata->getVisibility());
if (IGM.useDllStorage())
alias->setDLLStorageClass(metadata->getDLLStorageClass());
}
/// Emit the type metadata or metadata template for a class.
void irgen::emitClassMetadata(IRGenModule &IGM, ClassDecl *classDecl,
const StructLayout &layout,
const ClassLayout &fieldLayout) {
assert(!classDecl->isForeign());
// 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 isPattern;
bool canBeConstant;
if (classDecl->isGenericContext()) {
GenericClassMetadataBuilder builder(IGM, classDecl, init,
layout, fieldLayout);
builder.layout();
isPattern = true;
canBeConstant = false;
maybeEmitNominalTypeMetadataAccessFunction(classDecl, builder);
} else {
ClassMetadataBuilder builder(IGM, classDecl, init, layout, fieldLayout);
builder.layout();
isPattern = false;
canBeConstant = builder.canBeConstant();
maybeEmitNominalTypeMetadataAccessFunction(classDecl, builder);
}
CanType declaredType = classDecl->getDeclaredType()->getCanonicalType();
// For now, all type metadata is directly stored.
bool isIndirect = false;
StringRef section{};
if (classDecl->isObjC())
section = "__DATA,__objc_data, regular";
auto var = IGM.defineTypeMetadata(declaredType, isIndirect, isPattern,
canBeConstant,
init.finishAndCreateFuture(),
section);
// Add classes that don't require dynamic initialization to the
// ObjC class list.
if (IGM.ObjCInterop && !isPattern && !isIndirect &&
!doesClassMetadataRequireDynamicInitialization(IGM, classDecl)) {
// Emit the ObjC class symbol to make the class visible to ObjC.
if (classDecl->isObjC()) {
emitObjCClassSymbol(IGM, classDecl, var);
}
IGM.addObjCClass(var,
classDecl->getAttrs().hasAttribute<ObjCNonLazyRealizationAttr>());
}
}
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 an AST type, load its value witness table.
llvm::Value *
IRGenFunction::emitValueWitnessTableRef(CanType type) {
// See if we have a cached projection we can use.
if (auto cached = tryGetLocalTypeData(type,
LocalTypeDataKind::forValueWitnessTable())) {
return cached;
}
auto metadata = emitTypeMetadataRef(type);
auto vwtable = emitValueWitnessTableRefForMetadata(metadata);
setScopedLocalTypeData(type, LocalTypeDataKind::forValueWitnessTable(),
vwtable);
return vwtable;
}
/// 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) {
// See if we have a cached projection we can use.
if (auto cached = tryGetLocalTypeDataForLayout(type,
LocalTypeDataKind::forValueWitnessTable())) {
if (metadataSlot)
*metadataSlot = emitTypeMetadataRefForLayout(type);
return cached;
}
auto metadata = emitTypeMetadataRefForLayout(type);
if (metadataSlot) *metadataSlot = metadata;
auto vwtable = emitValueWitnessTableRefForMetadata(metadata);
setScopedLocalTypeDataForLayout(type,
LocalTypeDataKind::forValueWitnessTable(),
vwtable);
return vwtable;
}
/// Given a reference to class metadata of the given type,
/// load the fragile instance size and alignment of the class.
std::pair<llvm::Value *, llvm::Value *>
irgen::emitClassFragileInstanceSizeAndAlignMask(IRGenFunction &IGF,
ClassDecl *theClass,
llvm::Value *metadata) {
// FIXME: The below checks should capture this property already, but
// resilient class metadata layout is not fully implemented yet.
auto expansion = IGF.IGM.getResilienceExpansionForLayout(theClass);
if (IGF.IGM.isResilient(theClass, expansion)) {
return emitClassResilientInstanceSizeAndAlignMask(IGF, theClass, metadata);
}
// If the class has fragile fixed layout, return the constant size and
// alignment.
if (llvm::Constant *size
= tryEmitClassConstantFragileInstanceSize(IGF.IGM, theClass)) {
llvm::Constant *alignMask
= tryEmitClassConstantFragileInstanceAlignMask(IGF.IGM, theClass);
assert(alignMask && "static size without static align");
return {size, alignMask};
}
// Otherwise, load it from the metadata.
return emitClassResilientInstanceSizeAndAlignMask(IGF, theClass, metadata);
}
std::pair<llvm::Value *, llvm::Value *>
irgen::emitClassResilientInstanceSizeAndAlignMask(IRGenFunction &IGF,
ClassDecl *theClass,
llvm::Value *metadata) {
auto &layout = IGF.IGM.getMetadataLayout(theClass);
Address metadataAsBytes(IGF.Builder.CreateBitCast(metadata, IGF.IGM.Int8PtrTy),
IGF.IGM.getPointerAlignment());
Address slot = IGF.Builder.CreateConstByteArrayGEP(
metadataAsBytes,
layout.getInstanceSizeOffset());
slot = IGF.Builder.CreateBitCast(slot, IGF.IGM.Int32Ty->getPointerTo());
llvm::Value *size = IGF.Builder.CreateLoad(slot);
if (IGF.IGM.SizeTy != IGF.IGM.Int32Ty)
size = IGF.Builder.CreateZExt(size, IGF.IGM.SizeTy);
slot = IGF.Builder.CreateConstByteArrayGEP(
metadataAsBytes,
layout.getInstanceAlignMaskOffset());
slot = IGF.Builder.CreateBitCast(slot, IGF.IGM.Int16Ty->getPointerTo());
llvm::Value *alignMask = IGF.Builder.CreateLoad(slot);
alignMask = IGF.Builder.CreateZExt(alignMask, IGF.IGM.SizeTy);
return {size, alignMask};
}
/// Given a non-tagged object pointer, load a pointer to its class object.
llvm::Value *irgen::emitLoadOfObjCHeapMetadataRef(IRGenFunction &IGF,
llvm::Value *object) {
if (IGF.IGM.TargetInfo.hasISAMasking()) {
object = IGF.Builder.CreateBitCast(object,
IGF.IGM.IntPtrTy->getPointerTo());
llvm::Value *metadata =
IGF.Builder.CreateLoad(Address(object, IGF.IGM.getPointerAlignment()));
llvm::Value *mask = IGF.Builder.CreateLoad(IGF.IGM.getAddrOfObjCISAMask());
metadata = IGF.Builder.CreateAnd(metadata, mask);
metadata = IGF.Builder.CreateIntToPtr(metadata, IGF.IGM.TypeMetadataPtrTy);
return metadata;
} else if (IGF.IGM.TargetInfo.hasOpaqueISAs()) {
return emitHeapMetadataRefForUnknownHeapObject(IGF, object);
} else {
object = IGF.Builder.CreateBitCast(object,
IGF.IGM.TypeMetadataPtrTy->getPointerTo());
llvm::Value *metadata =
IGF.Builder.CreateLoad(Address(object, IGF.IGM.getPointerAlignment()));
return metadata;
}
}
/// Given a pointer to a heap object (i.e. definitely not a tagged
/// pointer), load its heap metadata pointer.
static llvm::Value *emitLoadOfHeapMetadataRef(IRGenFunction &IGF,
llvm::Value *object,
IsaEncoding isaEncoding,
bool suppressCast) {
switch (isaEncoding) {
case IsaEncoding::Pointer: {
// Drill into the object pointer. Rather than bitcasting, we make
// an effort to do something that should explode if we get something
// mistyped.
llvm::StructType *structTy =
cast<llvm::StructType>(
cast<llvm::PointerType>(object->getType())->getElementType());
llvm::Value *slot;
// We need a bitcast if we're dealing with an opaque class.
if (structTy->isOpaque()) {
auto metadataPtrPtrTy = IGF.IGM.TypeMetadataPtrTy->getPointerTo();
slot = IGF.Builder.CreateBitCast(object, metadataPtrPtrTy);
// Otherwise, make a GEP.
} else {
auto zero = llvm::ConstantInt::get(IGF.IGM.Int32Ty, 0);
SmallVector<llvm::Value*, 4> indexes;
indexes.push_back(zero);
do {
indexes.push_back(zero);
// Keep drilling down to the first element type.
auto eltTy = structTy->getElementType(0);
assert(isa<llvm::StructType>(eltTy) || eltTy == IGF.IGM.TypeMetadataPtrTy);
structTy = dyn_cast<llvm::StructType>(eltTy);
} while (structTy != nullptr);
slot = IGF.Builder.CreateInBoundsGEP(object, indexes);
if (!suppressCast) {
slot = IGF.Builder.CreateBitCast(slot,
IGF.IGM.TypeMetadataPtrTy->getPointerTo());
}
}
auto metadata = IGF.Builder.CreateLoad(Address(slot,
IGF.IGM.getPointerAlignment()));
if (IGF.IGM.EnableValueNames && object->hasName())
metadata->setName(llvm::Twine(object->getName()) + ".metadata");
return metadata;
}
case IsaEncoding::ObjC: {
// Feed the object pointer to object_getClass.
llvm::Value *objcClass = emitLoadOfObjCHeapMetadataRef(IGF, object);
objcClass = IGF.Builder.CreateBitCast(objcClass, IGF.IGM.TypeMetadataPtrTy);
return objcClass;
}
}
llvm_unreachable("Not a valid IsaEncoding.");
}
/// Given an object of class type, produce the heap metadata reference
/// as an %objc_class*.
llvm::Value *irgen::emitHeapMetadataRefForHeapObject(IRGenFunction &IGF,
llvm::Value *object,
CanType objectType,
bool suppressCast) {
ClassDecl *theClass = objectType.getClassOrBoundGenericClass();
if (theClass && isKnownNotTaggedPointer(IGF.IGM, theClass))
return emitLoadOfHeapMetadataRef(IGF, object,
getIsaEncodingForType(IGF.IGM, objectType),
suppressCast);
// OK, ask the runtime for the class pointer of this potentially-ObjC object.
return emitHeapMetadataRefForUnknownHeapObject(IGF, object);
}
llvm::Value *irgen::emitHeapMetadataRefForHeapObject(IRGenFunction &IGF,
llvm::Value *object,
SILType objectType,
bool suppressCast) {
return emitHeapMetadataRefForHeapObject(IGF, object,
objectType.getSwiftRValueType(),
suppressCast);
}
/// Given an opaque class instance pointer, produce the type metadata reference
/// as a %type*.
llvm::Value *irgen::emitDynamicTypeOfOpaqueHeapObject(IRGenFunction &IGF,
llvm::Value *object) {
object = IGF.Builder.CreateBitCast(object, IGF.IGM.ObjCPtrTy);
auto metadata = IGF.Builder.CreateCall(IGF.IGM.getGetObjectTypeFn(),
object,
object->getName() + ".Type");
metadata->setDoesNotThrow();
metadata->setDoesNotAccessMemory();
return metadata;
}
llvm::Value *irgen::
emitHeapMetadataRefForUnknownHeapObject(IRGenFunction &IGF,
llvm::Value *object) {
object = IGF.Builder.CreateBitCast(object, IGF.IGM.ObjCPtrTy);
auto metadata = IGF.Builder.CreateCall(IGF.IGM.getGetObjectClassFn(),
object,
object->getName() + ".Type");
metadata->setCallingConv(llvm::CallingConv::C);
metadata->setDoesNotThrow();
metadata->addAttribute(llvm::AttributeList::FunctionIndex,
llvm::Attribute::ReadOnly);
return metadata;
}
/// Given an object of class type, produce the type metadata reference
/// as a %type*.
llvm::Value *irgen::emitDynamicTypeOfHeapObject(IRGenFunction &IGF,
llvm::Value *object,
SILType objectType,
bool suppressCast) {
// If it is known to have swift metadata, just load.
if (hasKnownSwiftMetadata(IGF.IGM, objectType.getSwiftRValueType())) {
return emitLoadOfHeapMetadataRef(IGF, object,
getIsaEncodingForType(IGF.IGM, objectType.getSwiftRValueType()),
suppressCast);
}
// Okay, ask the runtime for the type metadata of this
// potentially-ObjC object.
return emitDynamicTypeOfOpaqueHeapObject(IGF, object);
}
/// Given a class metatype, produce the necessary heap metadata
/// reference. This is generally the metatype pointer, but may
/// instead be a reference type.
llvm::Value *irgen::emitClassHeapMetadataRefForMetatype(IRGenFunction &IGF,
llvm::Value *metatype,
CanType type) {
// If the type is known to have Swift metadata, this is trivial.
if (hasKnownSwiftMetadata(IGF.IGM, type))
return metatype;
// Otherwise, we inline a little operation here.
// Load the metatype kind.
auto metatypeKindAddr =
Address(IGF.Builder.CreateStructGEP(/*Ty=*/nullptr, metatype, 0),
IGF.IGM.getPointerAlignment());
auto metatypeKind =
IGF.Builder.CreateLoad(metatypeKindAddr, metatype->getName() + ".kind");
// Compare it with the class wrapper kind.
auto classWrapperKind =
llvm::ConstantInt::get(IGF.IGM.MetadataKindTy,
unsigned(MetadataKind::ObjCClassWrapper));
auto isObjCClassWrapper =
IGF.Builder.CreateICmpEQ(metatypeKind, classWrapperKind,
"isObjCClassWrapper");
// Branch based on that.
llvm::BasicBlock *contBB = IGF.createBasicBlock("metadataForClass.cont");
llvm::BasicBlock *wrapBB = IGF.createBasicBlock("isWrapper");
IGF.Builder.CreateCondBr(isObjCClassWrapper, wrapBB, contBB);
llvm::BasicBlock *origBB = IGF.Builder.GetInsertBlock();
// If it's a wrapper, load from the 'Class' field, which is at index 1.
// TODO: if we guaranteed that this load couldn't crash, we could use
// a select here instead, which might be profitable.
IGF.Builder.emitBlock(wrapBB);
auto classFromWrapper =
emitInvariantLoadFromMetadataAtIndex(IGF, metatype, 1,
IGF.IGM.TypeMetadataPtrTy);
IGF.Builder.CreateBr(contBB);
// Continuation block.
IGF.Builder.emitBlock(contBB);
auto phi = IGF.Builder.CreatePHI(IGF.IGM.TypeMetadataPtrTy, 2,
metatype->getName() + ".class");
phi->addIncoming(metatype, origBB);
phi->addIncoming(classFromWrapper, wrapBB);
return phi;
}
/// Load the correct virtual function for the given class method.
FunctionPointer irgen::emitVirtualMethodValue(IRGenFunction &IGF,
llvm::Value *base,
SILType baseType,
SILDeclRef method,
CanSILFunctionType methodType,
bool useSuperVTable) {
AbstractFunctionDecl *methodDecl
= cast<AbstractFunctionDecl>(method.getDecl());
// Find the vtable entry for this method.
SILDeclRef overridden = IGF.IGM.getSILTypes().getOverriddenVTableEntry(method);
// Find the metadata.
llvm::Value *metadata;
if (useSuperVTable) {
auto instanceTy = baseType;
if (auto metaTy = dyn_cast<MetatypeType>(baseType.getSwiftRValueType()))
instanceTy = SILType::getPrimitiveObjectType(metaTy.getInstanceType());
if (IGF.IGM.isResilient(instanceTy.getClassOrBoundGenericClass(),
ResilienceExpansion::Maximal)) {
// The derived type that is making the super call is resilient,
// for example we may be in an extension of a class outside of our
// resilience domain. So, we need to load the superclass metadata
// dynamically.
metadata = emitClassHeapMetadataRef(IGF, instanceTy.getSwiftRValueType(),
MetadataValueType::TypeMetadata);
auto superField = emitAddressOfSuperclassRefInClassMetadata(IGF, metadata);
metadata = IGF.Builder.CreateLoad(superField);
} else {
// Otherwise, we can directly load the statically known superclass's
// metadata.
auto superTy = instanceTy.getSuperclass();
metadata = emitClassHeapMetadataRef(IGF, superTy.getSwiftRValueType(),
MetadataValueType::TypeMetadata);
}
} else {
if ((isa<FuncDecl>(methodDecl) && cast<FuncDecl>(methodDecl)->isStatic()) ||
(isa<ConstructorDecl>(methodDecl) &&
method.kind == SILDeclRef::Kind::Allocator)) {
metadata = base;
} else {
metadata = emitHeapMetadataRefForHeapObject(IGF, base, baseType,
/*suppress cast*/ true);
}
}
// Use the type of the method we were type-checked against, not the
// type of the overridden method.
auto sig = IGF.IGM.getSignature(methodType);
auto declaringClass = cast<ClassDecl>(overridden.getDecl()->getDeclContext());
auto methodInfo =
IGF.IGM.getMetadataLayout(declaringClass).getMethodInfo(IGF, overridden);
auto offset = methodInfo.getOffset();
auto slot = IGF.emitAddressAtOffset(metadata, offset,
sig.getType()->getPointerTo(),
IGF.IGM.getPointerAlignment());
auto fnPtr = IGF.emitInvariantLoad(slot);
return FunctionPointer(fnPtr, sig);
}
//===----------------------------------------------------------------------===//
// Value types (structs and enums)
//===----------------------------------------------------------------------===//
namespace {
template <class Impl, class Base>
class ValueTypeMetadataBuilderBase : public Base {
using super = Base;
protected:
using super::asImpl;
using super::IGM;
using super::Target;
ConstantStructBuilder &B;
template <class DeclTy>
ValueTypeMetadataBuilderBase(IRGenModule &IGM, DeclTy *theDecl,
ConstantStructBuilder &B)
: super(IGM, theDecl), B(B) {}
CanType getParentType() const {
Type type = Target->getDeclaredTypeInContext();
Type parentType = type->getNominalParent();
if (parentType)
return parentType->getCanonicalType();
return CanType();
}
public:
void addParentMetadataRef() {
llvm::Constant *parentMetadata = nullptr;
if (auto parentType = getParentType()) {
parentMetadata =
tryEmitConstantTypeMetadataRef(IGM, parentType,
SymbolReferenceKind::Absolute)
.getDirectValue();
if (!parentMetadata) {
asImpl().flagUnfilledParent();
}
}
if (!parentMetadata)
parentMetadata = llvm::ConstantPointerNull::get(IGM.TypeMetadataPtrTy);
B.add(parentMetadata);
}
};
} // end anonymous namespace
static llvm::Value *
emitInPlaceValueTypeMetadataInitialization(IRGenFunction &IGF,
CanNominalType type,
llvm::Value *metadata,
bool hasUnfilledParent) {
// All the value types are basically similar.
assert(isa<StructType>(type) || isa<EnumType>(type));
// Initialize the parent-metadata field if it wasn't done statically.
if (hasUnfilledParent) {
CanType parentType = type.getParent();
assert(parentType);
// Value types hold the parent metadata as a far relative
// indirectable pointer.
llvm::Value *parentMetadata = IGF.emitTypeMetadataRef(parentType);
Address addr =
emitAddressOfParentMetadataSlot(IGF, metadata, type->getDecl());
IGF.Builder.CreateStore(parentMetadata, addr);
}
// Set up the value witness table if it's dependent.
SILType loweredType = IGF.IGM.getLoweredType(AbstractionPattern(type), type);
auto &ti = IGF.IGM.getTypeInfo(loweredType);
if (!ti.isFixedSize()) {
// We assume that that value witness table will already have been written
// into the metadata; just load it.
llvm::Value *vwtable = IGF.emitValueWitnessTableRefForMetadata(metadata);
// Initialize the metadata.
ti.initializeMetadata(IGF, metadata, vwtable, loweredType.getAddressType());
}
return metadata;
}
/// Create an access function for the type metadata of the given
/// non-generic nominal type.
static void createInPlaceValueTypeMetadataAccessFunction(IRGenModule &IGM,
NominalTypeDecl *typeDecl,
bool hasUnfilledParent) {
assert(!typeDecl->isGenericContext());
auto type =
cast<NominalType>(typeDecl->getDeclaredType()->getCanonicalType());
(void) getTypeMetadataAccessFunction(IGM, type, ForDefinition,
[&](IRGenFunction &IGF,
llvm::Constant *cacheVariable) {
return emitInPlaceTypeMetadataAccessFunctionBody(IGF, type, cacheVariable,
[&](IRGenFunction &IGF, llvm::Value *metadata) {
return emitInPlaceValueTypeMetadataInitialization(IGF, type, metadata,
hasUnfilledParent);
});
});
}
//===----------------------------------------------------------------------===//
// Structs
//===----------------------------------------------------------------------===//
namespace {
/// An adapter for laying out struct metadata.
template <class Impl>
class StructMetadataBuilderBase
: public ValueTypeMetadataBuilderBase<Impl,StructMetadataVisitor<Impl>>{
using super = ValueTypeMetadataBuilderBase<Impl,StructMetadataVisitor<Impl>>;
protected:
using super::IGM;
using super::Target;
using super::asImpl;
using super::B;
StructMetadataBuilderBase(IRGenModule &IGM, StructDecl *theStruct,
ConstantStructBuilder &B)
: super(IGM, theStruct, B) {
}
public:
void addMetadataFlags() {
B.addInt(IGM.MetadataKindTy, unsigned(MetadataKind::Struct));
}
void addNominalTypeDescriptor() {
llvm::Constant *descriptor =
StructNominalTypeDescriptorBuilder(IGM, Target).emit();
B.addFarRelativeAddress(descriptor);
}
void addFieldOffset(VarDecl *var) {
assert(var->hasStorage() &&
"storing field offset for computed property?!");
SILType structType =
IGM.getLoweredType(Target->getDeclaredTypeInContext());
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.IntPtrTy, 0);
}
}
void addGenericArgument(CanType type) {
B.addNullPointer(IGM.TypeMetadataPtrTy);
}
void addGenericWitnessTable(CanType type, ProtocolConformanceRef conf) {
B.addNullPointer(IGM.WitnessTablePtrTy);
}
};
class StructMetadataBuilder :
public StructMetadataBuilderBase<StructMetadataBuilder> {
bool HasUnfilledParent = false;
bool HasUnfilledFieldOffset = false;
public:
StructMetadataBuilder(IRGenModule &IGM, StructDecl *theStruct,
ConstantStructBuilder &B)
: StructMetadataBuilderBase(IGM, theStruct, B) {}
void flagUnfilledParent() {
HasUnfilledParent = true;
}
void flagUnfilledFieldOffset() {
HasUnfilledFieldOffset = true;
}
bool canBeConstant() {
return !HasUnfilledParent && !HasUnfilledFieldOffset;
}
void addValueWitnessTable() {
auto type = this->Target->getDeclaredType()->getCanonicalType();
B.add(emitValueWitnessTable(IGM, type));
}
void createMetadataAccessFunction() {
createInPlaceValueTypeMetadataAccessFunction(IGM, Target,
HasUnfilledParent);
}
};
/// Emit a value witness table for a fixed-layout generic type, or a null
/// placeholder if the value witness table is dependent on generic parameters.
/// Returns nullptr if the value witness table is dependent.
static llvm::Constant *
getValueWitnessTableForGenericValueType(IRGenModule &IGM,
NominalTypeDecl *decl,
bool &dependent) {
CanType unboundType
= decl->getDeclaredType()->getCanonicalType();
dependent = hasDependentValueWitnessTable(IGM, unboundType);
if (dependent)
return llvm::ConstantPointerNull::get(IGM.Int8PtrTy);
else
return emitValueWitnessTable(IGM, unboundType);
}
/// A builder for metadata templates.
class GenericStructMetadataBuilder :
public GenericMetadataBuilderBase<GenericStructMetadataBuilder,
StructMetadataBuilderBase<GenericStructMetadataBuilder>> {
typedef GenericMetadataBuilderBase super;
public:
GenericStructMetadataBuilder(IRGenModule &IGM, StructDecl *theStruct,
ConstantStructBuilder &B)
: super(IGM, theStruct, B) {}
llvm::Value *emitAllocateMetadata(IRGenFunction &IGF,
llvm::Value *metadataPattern,
llvm::Value *arguments) {
return IGF.Builder.CreateCall(IGM.getAllocateGenericValueMetadataFn(),
{metadataPattern, arguments});
}
void addParentMetadataRef() {
// Override to always use a fill op instead of a relocation.
if (CanType parentType = getParentType()) {
addFillOp(parentType, None, /*relative*/ false);
}
B.addInt(IGM.IntPtrTy, 0);
}
void flagUnfilledFieldOffset() {
// We just assume this might happen.
}
void addValueWitnessTable() {
B.add(getValueWitnessTableForGenericValueType(IGM, Target,
HasDependentVWT));
}
void addDependentValueWitnessTablePattern() {
emitDependentValueWitnessTablePattern(IGM, B,
Target->getDeclaredType()->getCanonicalType());
}
void emitInitializeMetadata(IRGenFunction &IGF,
llvm::Value *metadata,
llvm::Value *vwtable) {
// Nominal types are always preserved through SIL lowering.
auto structTy = Target->getDeclaredTypeInContext()->getCanonicalType();
IGM.getTypeInfoForUnlowered(structTy)
.initializeMetadata(IGF, metadata, vwtable,
IGF.IGM.getLoweredType(structTy));
}
};
} // end anonymous namespace
/// Emit the type metadata or metadata template for a struct.
void irgen::emitStructMetadata(IRGenModule &IGM, StructDecl *structDecl) {
// TODO: structs nested within generic types
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 = false;
maybeEmitNominalTypeMetadataAccessFunction(structDecl, builder);
} else {
StructMetadataBuilder builder(IGM, structDecl, init);
builder.layout();
isPattern = false;
canBeConstant = builder.canBeConstant();
maybeEmitNominalTypeMetadataAccessFunction(structDecl, builder);
}
CanType declaredType = structDecl->getDeclaredType()->getCanonicalType();
// For now, all type metadata is directly stored.
bool isIndirect = false;
IGM.defineTypeMetadata(declaredType, isIndirect, isPattern,
canBeConstant, init.finishAndCreateFuture());
}
// Enums
namespace {
template<class Impl>
class EnumMetadataBuilderBase
: public ValueTypeMetadataBuilderBase<Impl, EnumMetadataVisitor<Impl>> {
using super = ValueTypeMetadataBuilderBase<Impl, EnumMetadataVisitor<Impl>>;
protected:
using super::IGM;
using super::Target;
using super::B;
public:
EnumMetadataBuilderBase(IRGenModule &IGM, EnumDecl *theEnum,
ConstantStructBuilder &B)
: super(IGM, theEnum, B) {
}
void addMetadataFlags() {
auto kind = Target->classifyAsOptionalType()
? MetadataKind::Optional
: MetadataKind::Enum;
B.addInt(IGM.MetadataKindTy, unsigned(kind));
}
void addNominalTypeDescriptor() {
auto descriptor =
EnumNominalTypeDescriptorBuilder(IGM, Target).emit();
B.addFarRelativeAddress(descriptor);
}
void addGenericArgument(CanType type) {
B.addNullPointer(IGM.TypeMetadataPtrTy);
}
void addGenericWitnessTable(CanType type, ProtocolConformanceRef conf) {
B.addNullPointer(IGM.WitnessTablePtrTy);
}
};
class EnumMetadataBuilder
: public EnumMetadataBuilderBase<EnumMetadataBuilder> {
bool HasUnfilledParent = false;
bool HasUnfilledPayloadSize = false;
public:
EnumMetadataBuilder(IRGenModule &IGM, EnumDecl *theEnum,
ConstantStructBuilder &B)
: EnumMetadataBuilderBase(IGM, theEnum, B) {}
void addValueWitnessTable() {
auto type = Target->getDeclaredType()->getCanonicalType();
B.add(emitValueWitnessTable(IGM, type));
}
void addPayloadSize() {
auto enumTy = Target->getDeclaredTypeInContext()->getCanonicalType();
auto &enumTI = IGM.getTypeInfoForUnlowered(enumTy);
if (!enumTI.isFixedSize(ResilienceExpansion::Maximal)) {
B.addInt(IGM.IntPtrTy, 0);
HasUnfilledPayloadSize = true;
return;
}
assert(!enumTI.isFixedSize(ResilienceExpansion::Minimal) &&
"non-generic, non-resilient enums don't need payload size in metadata");
auto &strategy = getEnumImplStrategy(IGM, enumTy);
B.addInt(IGM.IntPtrTy, strategy.getPayloadSizeForMetadata());
}
void flagUnfilledParent() {
HasUnfilledParent = true;
}
bool canBeConstant() {
return !HasUnfilledParent && !HasUnfilledPayloadSize;
}
void createMetadataAccessFunction() {
createInPlaceValueTypeMetadataAccessFunction(IGM, Target,
HasUnfilledParent);
}
};
class GenericEnumMetadataBuilder
: public GenericMetadataBuilderBase<GenericEnumMetadataBuilder,
EnumMetadataBuilderBase<GenericEnumMetadataBuilder>>
{
public:
GenericEnumMetadataBuilder(IRGenModule &IGM, EnumDecl *theEnum,
ConstantStructBuilder &B)
: GenericMetadataBuilderBase(IGM, theEnum, B) {}
llvm::Value *emitAllocateMetadata(IRGenFunction &IGF,
llvm::Value *metadataPattern,
llvm::Value *arguments) {
return IGF.Builder.CreateCall(IGM.getAllocateGenericValueMetadataFn(),
{metadataPattern, arguments});
}
void addParentMetadataRef() {
// Override to always use a fill op instead of a relocation.
if (CanType parentType = getParentType()) {
addFillOp(parentType, None, /*relative*/ false);
}
B.addInt(IGM.IntPtrTy, 0);
}
void addValueWitnessTable() {
B.add(getValueWitnessTableForGenericValueType(IGM, Target,
HasDependentVWT));
}
void addDependentValueWitnessTablePattern() {
emitDependentValueWitnessTablePattern(IGM, B,
Target->getDeclaredType()->getCanonicalType());
}
void addPayloadSize() {
// In all cases where a payload size is demanded in the metadata, it's
// runtime-dependent, so fill in a zero here.
auto enumTy = Target->getDeclaredTypeInContext()->getCanonicalType();
auto &enumTI = IGM.getTypeInfoForUnlowered(enumTy);
(void) enumTI;
assert(!enumTI.isFixedSize(ResilienceExpansion::Minimal) &&
"non-generic, non-resilient enums don't need payload size in metadata");
B.addInt(IGM.IntPtrTy, 0);
}
void emitInitializeMetadata(IRGenFunction &IGF,
llvm::Value *metadata,
llvm::Value *vwtable) {
// Nominal types are always preserved through SIL lowering.
auto enumTy = Target->getDeclaredTypeInContext()->getCanonicalType();
IGM.getTypeInfoForUnlowered(enumTy)
.initializeMetadata(IGF, metadata, vwtable,
IGF.IGM.getLoweredType(enumTy));
}
};
} // end anonymous namespace
void irgen::emitEnumMetadata(IRGenModule &IGM, EnumDecl *theEnum) {
// TODO: enums nested inside generic types
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 = false;
maybeEmitNominalTypeMetadataAccessFunction(theEnum, builder);
} else {
EnumMetadataBuilder builder(IGM, theEnum, init);
builder.layout();
isPattern = false;
canBeConstant = builder.canBeConstant();
maybeEmitNominalTypeMetadataAccessFunction(theEnum, builder);
}
CanType declaredType = theEnum->getDeclaredType()->getCanonicalType();
// For now, all type metadata is directly stored.
bool isIndirect = false;
IGM.defineTypeMetadata(declaredType, isIndirect, 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 {
/// A CRTP layout class for foreign class metadata.
template <class Impl>
class ForeignClassMetadataVisitor
: public NominalMetadataVisitor<Impl> {
using super = NominalMetadataVisitor<Impl>;
protected:
ClassDecl *Target;
using super::asImpl;
public:
ForeignClassMetadataVisitor(IRGenModule &IGM, ClassDecl *target)
: super(IGM), Target(target) {}
void layout() {
super::layout();
asImpl().addSuperClass();
asImpl().addReservedWord();
asImpl().addReservedWord();
asImpl().addReservedWord();
}
bool requiresInitializationFunction() {
// TODO: superclasses?
return false;
}
CanType getTargetType() const {
return Target->getDeclaredType()->getCanonicalType();
}
};
/// An adapter that turns a metadata layout class into a foreign metadata
/// layout class. Foreign metadata has an additional header that
template<typename Impl, typename Base>
class ForeignMetadataBuilderBase : public Base {
typedef Base super;
protected:
using super::IGM;
using super::asImpl;
using super::B;
template <class... T>
ForeignMetadataBuilderBase(T &&...args) : super(std::forward<T>(args)...) {}
Size AddressPoint = Size::invalid();
bool computeUnfilledParent() {
if (auto parentType = asImpl().getTargetType().getNominalParent()) {
return !tryEmitConstantTypeMetadataRef(IGM, parentType,
SymbolReferenceKind::Absolute);
}
return false;
}
public:
void layout() {
if (asImpl().requiresInitializationFunction())
asImpl().addInitializationFunction();
asImpl().addForeignName();
asImpl().addUniquePointer();
asImpl().addForeignFlags();
super::layout();
}
void addForeignFlags() {
int64_t flags = 0;
if (asImpl().requiresInitializationFunction()) flags |= 1;
B.addInt(IGM.IntPtrTy, flags);
}
void addForeignName() {
CanType targetType = asImpl().getTargetType();
B.add(getMangledTypeName(IGM, targetType));
}
void addUniquePointer() {
B.addNullPointer(IGM.TypeMetadataPtrTy);
}
void addInitializationFunction() {
auto type = cast<NominalType>(asImpl().getTargetType());
auto fnTy = llvm::FunctionType::get(IGM.VoidTy, {IGM.TypeMetadataPtrTy},
/*variadic*/ false);
llvm::Function *fn = llvm::Function::Create(fnTy,
llvm::GlobalValue::PrivateLinkage,
Twine("initialize_metadata_")
+ type->getDecl()->getName().str(),
&IGM.Module);
fn->setAttributes(IGM.constructInitialAttributes());
// Set up the function.
IRGenFunction IGF(IGM, fn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, fn);
// Emit the initialization.
llvm::Value *metadata = IGF.collectParameters().claimNext();
asImpl().emitInitialization(IGF, metadata);
IGF.Builder.CreateRetVoid();
B.add(fn);
}
void noteAddressPoint() {
AddressPoint = B.getNextOffsetFromGlobal();
}
Size getOffsetOfAddressPoint() const { return AddressPoint; }
};
class ForeignClassMetadataBuilder;
class ForeignClassMetadataBuilderBase :
public ForeignClassMetadataVisitor<ForeignClassMetadataBuilder> {
protected:
ConstantStructBuilder &B;
ForeignClassMetadataBuilderBase(IRGenModule &IGM, ClassDecl *target,
ConstantStructBuilder &B)
: ForeignClassMetadataVisitor(IGM, target), B(B) {}
};
/// A builder for ForeignClassMetadata.
class ForeignClassMetadataBuilder :
public ForeignMetadataBuilderBase<ForeignClassMetadataBuilder,
ForeignClassMetadataBuilderBase> {
public:
ForeignClassMetadataBuilder(IRGenModule &IGM, ClassDecl *target,
ConstantStructBuilder &B)
: ForeignMetadataBuilderBase(IGM, target, B) {}
void emitInitialization(IRGenFunction &IGF, llvm::Value *metadata) {
// TODO: superclasses?
llvm_unreachable("no supported forms of initialization");
}
// Visitor methods.
void addValueWitnessTable() {
// Without Objective-C interop, foreign classes must still use
// Swift native reference counting.
auto type = (IGM.ObjCInterop
? IGM.Context.TheUnknownObjectType
: IGM.Context.TheNativeObjectType);
auto wtable = IGM.getAddrOfValueWitnessTable(type);
B.add(wtable);
}
void addMetadataFlags() {
B.addInt(IGM.MetadataKindTy, (unsigned) MetadataKind::ForeignClass);
}
void addSuperClass() {
// TODO: superclasses
B.addNullPointer(IGM.TypeMetadataPtrTy);
}
void addReservedWord() {
B.addNullPointer(IGM.Int8PtrTy);
}
};
/// A builder for ForeignStructMetadata.
class ForeignStructMetadataBuilder :
public ForeignMetadataBuilderBase<ForeignStructMetadataBuilder,
StructMetadataBuilderBase<ForeignStructMetadataBuilder>>
{
bool HasUnfilledParent = false;
public:
ForeignStructMetadataBuilder(IRGenModule &IGM, StructDecl *target,
ConstantStructBuilder &builder)
: ForeignMetadataBuilderBase(IGM, target, builder) {
HasUnfilledParent = computeUnfilledParent();
}
CanType getTargetType() const {
return Target->getDeclaredType()->getCanonicalType();
}
bool requiresInitializationFunction() const {
return HasUnfilledParent;
}
void emitInitialization(IRGenFunction &IGF, llvm::Value *metadata) {
if (HasUnfilledParent) {
auto parentType = getTargetType().getNominalParent();
auto parentMetadata = IGF.emitTypeMetadataRef(parentType);
Address slot =
emitAddressOfParentMetadataSlot(IGF, metadata, this->Target);
IGF.Builder.CreateStore(parentMetadata, slot);
}
}
void addValueWitnessTable() {
auto type = this->Target->getDeclaredType()->getCanonicalType();
B.add(emitValueWitnessTable(IGM, type));
}
void flagUnfilledParent() {
assert(HasUnfilledParent);
}
void flagUnfilledFieldOffset() {
llvm_unreachable("foreign type with non-fixed layout?");
}
};
/// A builder for ForeignEnumMetadata.
class ForeignEnumMetadataBuilder :
public ForeignMetadataBuilderBase<ForeignEnumMetadataBuilder,
EnumMetadataBuilderBase<ForeignEnumMetadataBuilder>>
{
bool HasUnfilledParent = false;
public:
ForeignEnumMetadataBuilder(IRGenModule &IGM, EnumDecl *target,
ConstantStructBuilder &builder)
: ForeignMetadataBuilderBase(IGM, target, builder) {
HasUnfilledParent = computeUnfilledParent();
}
CanType getTargetType() const {
return Target->getDeclaredType()->getCanonicalType();
}
bool requiresInitializationFunction() const {
return HasUnfilledParent;
}
void emitInitialization(IRGenFunction &IGF, llvm::Value *metadata) {
if (HasUnfilledParent) {
auto parentType = getTargetType().getNominalParent();
auto parentMetadata = IGF.emitTypeMetadataRef(parentType);
Address slot =
emitAddressOfParentMetadataSlot(IGF, metadata, this->Target);
IGF.Builder.CreateStore(parentMetadata, slot);
}
}
void addValueWitnessTable() {
auto type = this->Target->getDeclaredType()->getCanonicalType();
B.add(emitValueWitnessTable(IGM, type));
}
void addPayloadSize() const {
llvm_unreachable("nongeneric enums shouldn't need payload size in metadata");
}
void flagUnfilledParent() {
assert(HasUnfilledParent);
}
};
} // end anonymous namespace
llvm::Constant *
IRGenModule::getAddrOfForeignTypeMetadataCandidate(CanType type) {
// What we save in GlobalVars is actually the offsetted value.
auto entity = LinkEntity::forForeignTypeMetadataCandidate(type);
if (auto entry = GlobalVars[entity])
return entry;
// Create a temporary base for relative references.
ConstantInitBuilder builder(*this);
auto init = builder.beginStruct();
init.setPacked(true);
// Compute the constant initializer and the offset of the type
// metadata candidate within it.
Size addressPoint;
if (auto classType = dyn_cast<ClassType>(type)) {
assert(!classType.getParent());
auto classDecl = classType->getDecl();
assert(classDecl->isForeign());
ForeignClassMetadataBuilder builder(*this, classDecl, init);
builder.layout();
addressPoint = builder.getOffsetOfAddressPoint();
} else if (auto structType = dyn_cast<StructType>(type)) {
auto structDecl = structType->getDecl();
assert(isa<ClangModuleUnit>(structDecl->getModuleScopeContext()));
ForeignStructMetadataBuilder builder(*this, structDecl, init);
builder.layout();
addressPoint = builder.getOffsetOfAddressPoint();
} else if (auto enumType = dyn_cast<EnumType>(type)) {
auto enumDecl = enumType->getDecl();
assert(enumDecl->hasClangNode());
ForeignEnumMetadataBuilder builder(*this, enumDecl, init);
builder.layout();
addressPoint = builder.getOffsetOfAddressPoint();
} else {
llvm_unreachable("foreign metadata for unexpected type?!");
}
auto definition = init.finishAndCreateFuture();
// Create the global variable.
LinkInfo link = LinkInfo::get(*this, entity, ForDefinition);
auto var =
createVariable(*this, link, definition.getType(), getPointerAlignment());
definition.installInGlobal(var);
// Apply the offset.
llvm::Constant *result = var;
result = llvm::ConstantExpr::getBitCast(result, Int8PtrTy);
result = llvm::ConstantExpr::getInBoundsGetElementPtr(
Int8Ty, result, getSize(addressPoint));
result = llvm::ConstantExpr::getBitCast(result, TypeMetadataPtrTy);
// Only remember the offset.
GlobalVars[entity] = result;
if (NominalTypeDecl *Nominal = type->getAnyNominal()) {
addLazyConformances(Nominal);
}
return result;
}
// Protocols
/// Get the runtime identifier for a special protocol, if any.
SpecialProtocol irgen::getSpecialProtocolID(ProtocolDecl *P) {
auto known = P->getKnownProtocolKind();
if (!known)
return SpecialProtocol::None;
switch (*known) {
case KnownProtocolKind::Error:
return SpecialProtocol::Error;
// The other known protocols aren't special at runtime.
case KnownProtocolKind::Sequence:
case KnownProtocolKind::IteratorProtocol:
case KnownProtocolKind::RawRepresentable:
case KnownProtocolKind::Equatable:
case KnownProtocolKind::Hashable:
case KnownProtocolKind::Comparable:
case KnownProtocolKind::ObjectiveCBridgeable:
case KnownProtocolKind::DestructorSafeContainer:
case KnownProtocolKind::SwiftNewtypeWrapper:
case KnownProtocolKind::ExpressibleByArrayLiteral:
case KnownProtocolKind::ExpressibleByBooleanLiteral:
case KnownProtocolKind::ExpressibleByDictionaryLiteral:
case KnownProtocolKind::ExpressibleByExtendedGraphemeClusterLiteral:
case KnownProtocolKind::ExpressibleByFloatLiteral:
case KnownProtocolKind::ExpressibleByIntegerLiteral:
case KnownProtocolKind::ExpressibleByStringInterpolation:
case KnownProtocolKind::ExpressibleByStringLiteral:
case KnownProtocolKind::ExpressibleByNilLiteral:
case KnownProtocolKind::ExpressibleByUnicodeScalarLiteral:
case KnownProtocolKind::ExpressibleByColorLiteral:
case KnownProtocolKind::ExpressibleByImageLiteral:
case KnownProtocolKind::ExpressibleByFileReferenceLiteral:
case KnownProtocolKind::ExpressibleByBuiltinBooleanLiteral:
case KnownProtocolKind::ExpressibleByBuiltinUTF16ExtendedGraphemeClusterLiteral:
case KnownProtocolKind::ExpressibleByBuiltinExtendedGraphemeClusterLiteral:
case KnownProtocolKind::ExpressibleByBuiltinFloatLiteral:
case KnownProtocolKind::ExpressibleByBuiltinIntegerLiteral:
case KnownProtocolKind::ExpressibleByBuiltinStringLiteral:
case KnownProtocolKind::ExpressibleByBuiltinUTF16StringLiteral:
case KnownProtocolKind::ExpressibleByBuiltinUnicodeScalarLiteral:
case KnownProtocolKind::OptionSet:
case KnownProtocolKind::BridgedNSError:
case KnownProtocolKind::BridgedStoredNSError:
case KnownProtocolKind::CFObject:
case KnownProtocolKind::ErrorCodeProtocol:
case KnownProtocolKind::ExpressibleByBuiltinConstStringLiteral:
case KnownProtocolKind::ExpressibleByBuiltinConstUTF16StringLiteral:
case KnownProtocolKind::CodingKey:
case KnownProtocolKind::Encodable:
case KnownProtocolKind::Decodable:
return SpecialProtocol::None;
}
llvm_unreachable("Not a valid KnownProtocolKind.");
}
namespace {
class ProtocolDescriptorBuilder {
IRGenModule &IGM;
ConstantStructBuilder &B;
ProtocolDecl *Protocol;
SILDefaultWitnessTable *DefaultWitnesses;
public:
ProtocolDescriptorBuilder(IRGenModule &IGM, ProtocolDecl *protocol,
ConstantStructBuilder &B,
SILDefaultWitnessTable *defaultWitnesses)
: IGM(IGM), B(B), Protocol(protocol),
DefaultWitnesses(defaultWitnesses) {}
void layout() {
addObjCCompatibilityIsa();
addName();
addInherited();
addObjCCompatibilityTables();
addSize();
addFlags();
addRequirements();
B.suggestType(IGM.ProtocolDescriptorStructTy);
}
void addObjCCompatibilityIsa() {
// The ObjC runtime will drop a reference to its magic Protocol class
// here.
B.addNullPointer(IGM.Int8PtrTy);
}
void addName() {
// Include the _Tt prefix. Since Swift protocol descriptors are laid
// out to look like ObjC Protocol* objects, the name has to clearly be
// a Swift mangled name.
IRGenMangler mangler;
std::string Name =
mangler.mangleForProtocolDescriptor(Protocol->getDeclaredType());
auto global = IGM.getAddrOfGlobalString(Name);
B.add(global);
}
void addInherited() {
// If there are no inherited protocols, produce null.
auto inherited = Protocol->getInheritedProtocols();
if (inherited.empty()) {
B.addNullPointer(IGM.Int8PtrTy);
return;
}
// Otherwise, collect references to all of the inherited protocol
// descriptors.
SmallVector<llvm::Constant*, 4> inheritedDescriptors;
inheritedDescriptors.push_back(IGM.getSize(Size(inherited.size())));
for (ProtocolDecl *p : inherited) {
auto descriptor = IGM.getAddrOfProtocolDescriptor(p);
inheritedDescriptors.push_back(descriptor);
}
auto inheritedInit = llvm::ConstantStruct::getAnon(inheritedDescriptors);
auto inheritedVar = new llvm::GlobalVariable(IGM.Module,
inheritedInit->getType(),
/*isConstant*/ true,
llvm::GlobalValue::PrivateLinkage,
inheritedInit);
B.addBitCast(inheritedVar, IGM.Int8PtrTy);
}
void addObjCCompatibilityTables() {
// Required instance methods
B.addNullPointer(IGM.Int8PtrTy);
// Required class methods
B.addNullPointer(IGM.Int8PtrTy);
// Optional instance methods
B.addNullPointer(IGM.Int8PtrTy);
// Optional class methods
B.addNullPointer(IGM.Int8PtrTy);
// Properties
B.addNullPointer(IGM.Int8PtrTy);
}
void addSize() {
// The number of fields so far in words, plus 4 bytes for size and
// 4 bytes for flags.
B.addInt32(B.getNextOffsetFromGlobal().getValue() + 4 + 4);
}
void addFlags() {
auto flags = ProtocolDescriptorFlags()
.withSwift(true)
.withClassConstraint(Protocol->requiresClass()
? ProtocolClassConstraint::Class
: ProtocolClassConstraint::Any)
.withDispatchStrategy(
Lowering::TypeConverter::getProtocolDispatchStrategy(Protocol))
.withSpecialProtocol(getSpecialProtocolID(Protocol));
if (DefaultWitnesses)
flags = flags.withResilient(true);
B.addInt32(flags.getIntValue());
}
void addRequirements() {
auto &pi = IGM.getProtocolInfo(Protocol);
B.addInt16(DefaultWitnesses
? DefaultWitnesses->getMinimumWitnessTableSize()
: pi.getNumWitnesses());
B.addInt16(pi.getNumWitnesses());
// If there are no entries, just add a null reference and return.
if (pi.getNumWitnesses() == 0) {
B.addInt(IGM.RelativeAddressTy, 0);
return;
}
#ifndef NDEBUG
unsigned numDefaultWitnesses = 0;
#endif
ConstantInitBuilder reqtBuilder(IGM);
auto reqtsArray = reqtBuilder.beginArray(IGM.ProtocolRequirementStructTy);
for (auto &entry : pi.getWitnessEntries()) {
auto reqt = reqtsArray.beginStruct(IGM.ProtocolRequirementStructTy);
auto info = getRequirementInfo(entry);
// Flags.
reqt.addInt32(info.Flags.getIntValue());
// Default implementation.
reqt.addRelativeAddressOrNull(info.DefaultImpl);
#ifndef NDEBUG
assert((info.DefaultImpl || numDefaultWitnesses == 0) &&
"adding mandatory witness after defaulted witness");
if (info.DefaultImpl) numDefaultWitnesses++;
#endif
reqt.finishAndAddTo(reqtsArray);
}
#ifndef NDEBUG
if (DefaultWitnesses) {
assert(numDefaultWitnesses
== DefaultWitnesses->getDefaultWitnessTableSize() &&
"didn't use all the default witnesses!");
} else {
assert(numDefaultWitnesses == 0);
}
#endif
auto global =
reqtsArray.finishAndCreateGlobal("", Alignment(4), /*constant*/ true,
llvm::GlobalVariable::InternalLinkage);
global->setUnnamedAddr(llvm::GlobalVariable::UnnamedAddr::Global);
B.addRelativeOffset(IGM.Int32Ty, global);
}
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);
return { flags, nullptr };
}
if (entry.isAssociatedConformance()) {
auto flags = Flags(Flags::Kind::AssociatedConformanceAccessFunction);
return { flags, nullptr };
}
assert(entry.isFunction());
auto func = entry.getFunction();
// Classify the function.
auto flags = getMethodDescriptorFlags<Flags>(func);
// Look for a default witness.
llvm::Constant *defaultImpl = findDefaultWitness(func);
return { flags, defaultImpl };
}
llvm::Constant *findDefaultWitness(AbstractFunctionDecl *func) {
if (!DefaultWitnesses) return nullptr;
for (auto &entry : DefaultWitnesses->getResilientDefaultEntries()) {
if (entry.getRequirement().getDecl() != func)
continue;
return IGM.getAddrOfSILFunction(entry.getWitness(), NotForDefinition);
}
return nullptr;
}
};
} // end anonymous namespace
/// Emit global structures associated with the given protocol. This comprises
/// the protocol descriptor, and for ObjC interop, references to the descriptor
/// that the ObjC runtime uses for uniquing.
void IRGenModule::emitProtocolDecl(ProtocolDecl *protocol) {
// Emit remote reflection metadata for the protocol.
emitFieldMetadataRecord(protocol);
// If the protocol is Objective-C-compatible, go through the path that
// produces an ObjC-compatible protocol_t.
if (protocol->isObjC()) {
// In JIT mode, we need to create protocol descriptors using the ObjC
// runtime in JITted code.
if (IRGen.Opts.UseJIT)
return;
// Native ObjC protocols are emitted on-demand in ObjC and uniqued by the
// runtime; we don't need to try to emit a unique descriptor symbol for them.
if (protocol->hasClangNode())
return;
getObjCProtocolGlobalVars(protocol);
return;
}
SILDefaultWitnessTable *defaultWitnesses = nullptr;
if (!protocol->hasFixedLayout())
defaultWitnesses = getSILModule().lookUpDefaultWitnessTable(protocol);
ConstantInitBuilder initBuilder(*this);
auto init = initBuilder.beginStruct();
ProtocolDescriptorBuilder builder(*this, protocol, init, defaultWitnesses);
builder.layout();
auto var = cast<llvm::GlobalVariable>(
getAddrOfProtocolDescriptor(protocol, init.finishAndCreateFuture()));
var->setConstant(true);
}
/// \brief Load a reference to the protocol descriptor for the given protocol.
///
/// For Swift protocols, this is a constant reference to the protocol descriptor
/// symbol.
/// For ObjC protocols, descriptors are uniqued at runtime by the ObjC runtime.
/// We need to load the unique reference from a global variable fixed up at
/// startup.
llvm::Value *irgen::emitProtocolDescriptorRef(IRGenFunction &IGF,
ProtocolDecl *protocol) {
if (!protocol->isObjC())
return IGF.IGM.getAddrOfProtocolDescriptor(protocol);
auto refVar = IGF.IGM.getAddrOfObjCProtocolRef(protocol, NotForDefinition);
llvm::Value *val
= IGF.Builder.CreateLoad(refVar, IGF.IGM.getPointerAlignment());
val = IGF.Builder.CreateBitCast(val,
IGF.IGM.ProtocolDescriptorStructTy->getPointerTo());
return val;
}
//===----------------------------------------------------------------------===//
// Other metadata.
//===----------------------------------------------------------------------===//
llvm::Value *irgen::emitMetatypeInstanceType(IRGenFunction &IGF,
llvm::Value *metatypeMetadata) {
// The instance type field of MetatypeMetadata is immediately after
// the isa field.
return emitInvariantLoadFromMetadataAtIndex(IGF, metatypeMetadata, 1,
IGF.IGM.TypeMetadataPtrTy);
}