static void boxIndirectEnumPayload(SILGenFunction &gen,
ManagedValue &payload,
SILLocation loc,
EnumElementDecl *element) {
// If the payload is indirect, we'll need to box it.
if (payload && (element->isIndirect() ||
element->getParentEnum()->isIndirect())) {
auto box = gen.B.createAllocBox(loc, payload.getType());
payload.forwardInto(gen, loc, box->getAddressResult());
payload = gen.emitManagedRValueWithCleanup(box);
}
}
/// Emit a materializeForSet operation that simply loads the l-value
/// into the result buffer. This operation creates a callback to write
/// the l-value back.
SILValue
MaterializeForSetEmitter::emitUsingGetterSetter(SILGenFunction &gen,
SILLocation loc,
ManagedValue self,
RValue &&indices,
SILValue resultBuffer,
SILValue callbackBuffer,
SILFunction *&callback) {
// Copy the indices into the callback storage.
const TypeLowering *indicesTL = nullptr;
CleanupHandle indicesCleanup = CleanupHandle::invalid();
CanType indicesFormalType;
if (isa<SubscriptDecl>(WitnessStorage)) {
indicesFormalType = indices.getType();
indicesTL = &gen.getTypeLowering(indicesFormalType);
SILValue allocatedCallbackBuffer =
gen.B.createAllocValueBuffer(loc, indicesTL->getLoweredType(),
callbackBuffer);
// Emit into the buffer.
auto init = gen.useBufferAsTemporary(loc, allocatedCallbackBuffer,
*indicesTL);
indicesCleanup = init->getInitializedCleanup();
indices.copyInto(gen, init.get(), loc);
}
// Set up the result buffer.
resultBuffer =
gen.B.createPointerToAddress(loc, resultBuffer,
Conformance
? RequirementStorageType.getAddressType()
: WitnessStorageType.getAddressType());
TemporaryInitialization init(resultBuffer, CleanupHandle::invalid());
// Evaluate the getter into the result buffer.
LValue lv = buildLValue(gen, loc, self, std::move(indices), AccessKind::Read);
ManagedValue result = gen.emitLoadOfLValue(loc, std::move(lv),
SGFContext(&init));
if (!result.isInContext()) {
result.forwardInto(gen, loc, resultBuffer);
}
// Forward the cleanup on the saved indices.
if (indicesCleanup.isValid()) {
gen.Cleanups.setCleanupState(indicesCleanup, CleanupState::Dead);
}
callback = createSetterCallback(gen.F, indicesTL, indicesFormalType);
return resultBuffer;
}
SILValue Lowering::emitIsa(SILGenFunction &SGF, SILLocation loc,
Expr *operand, Type targetType,
CheckedCastKind castKind) {
// Handle collection downcasts separately.
if (castKind == CheckedCastKind::ArrayDowncast ||
castKind == CheckedCastKind::DictionaryDowncast ||
castKind == CheckedCastKind::SetDowncast) {
ManagedValue operandMV = SGF.emitRValueAsSingleValue(operand);
ManagedValue optValue = emitCollectionDowncastExpr(
SGF, operandMV, operand->getType(), loc,
targetType,
SGFContext(), /*conditional=*/true)
.getAsSingleValue(SGF, loc);
// Materialize the input.
SILValue optValueTemp;
if (optValue.getType().isAddress()) {
optValueTemp = optValue.forward(SGF);
} else {
optValueTemp = SGF.emitTemporaryAllocation(loc, optValue.getType());
optValue.forwardInto(SGF, loc, optValueTemp);
}
return SGF.emitDoesOptionalHaveValue(loc, optValueTemp);
}
// Prepare a jump destination here.
ExitableFullExpr scope(SGF, CleanupLocation::get(loc));
auto i1Ty = SILType::getBuiltinIntegerType(1, SGF.getASTContext());
SGF.emitCheckedCastBranch(loc, operand, targetType, SGFContext(),
[&](ManagedValue value) {
SILValue yes = SGF.B.createIntegerLiteral(loc, i1Ty, 1);
SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc, yes);
},
[&] {
SILValue no = SGF.B.createIntegerLiteral(loc, i1Ty, 0);
SGF.Cleanups.emitBranchAndCleanups(scope.getExitDest(), loc, no);
});
auto contBB = scope.exit();
auto isa = new (SGF.SGM.M) SILArgument(contBB, i1Ty);
return isa;
}
static void emitAddressOnlyEnumConstructor(SILGenFunction &gen,
SILType enumTy,
EnumElementDecl *element) {
RegularLocation Loc(element);
CleanupLocation CleanupLoc(element);
Loc.markAutoGenerated();
// Emit the indirect return slot.
auto &AC = gen.getASTContext();
auto VD = new (AC) ParamDecl(/*IsLet*/ false, SourceLoc(),
AC.getIdentifier("$return_value"),
SourceLoc(),
AC.getIdentifier("$return_value"),
enumTy.getSwiftType(),
element->getDeclContext());
SILValue resultSlot
= new (gen.F.getModule()) SILArgument(gen.F.begin(), enumTy, VD);
Scope scope(gen.Cleanups, CleanupLoc);
// Emit the exploded constructor argument.
ManagedValue argValue;
if (element->hasArgumentType()) {
RValue arg = emitImplicitValueConstructorArg
(gen, Loc, element->getArgumentType()->getCanonicalType(),
element->getDeclContext());
argValue = std::move(arg).getAsSingleValue(gen, Loc);
}
emitConstructorMetatypeArg(gen, element);
boxIndirectEnumPayload(gen, argValue, Loc, element);
// Store the data, if any.
if (argValue) {
SILValue resultData = gen.B.createInitEnumDataAddr(element, resultSlot,
element, argValue.getType().getAddressType());
argValue.forwardInto(gen, element, resultData);
}
// Apply the tag.
gen.B.createInjectEnumAddr(Loc, resultSlot, element);
scope.pop();
gen.B.createReturn(ImplicitReturnLocation::getImplicitReturnLoc(Loc),
gen.emitEmptyTuple(element));
}
// FIXME: With some changes to their callers, all of the below functions
// could be re-worked to use emitInjectEnum().
ManagedValue
SILGenFunction::emitInjectOptional(SILLocation loc,
const TypeLowering &optTL,
SGFContext ctxt,
llvm::function_ref<ManagedValue(SGFContext)> generator) {
SILType optTy = optTL.getLoweredType();
SILType objectTy = optTy.getAnyOptionalObjectType();
assert(objectTy && "expected type was not optional");
auto someDecl = getASTContext().getOptionalSomeDecl();
// If the value is loadable, just emit and wrap.
// TODO: honor +0 contexts?
if (optTL.isLoadable() || !silConv.useLoweredAddresses()) {
ManagedValue objectResult = generator(SGFContext());
auto some = B.createEnum(loc, objectResult.forward(*this), someDecl, optTy);
return emitManagedRValueWithCleanup(some, optTL);
}
// Otherwise it's address-only; try to avoid spurious copies by
// evaluating into the context.
// Prepare a buffer for the object value.
return B.bufferForExpr(
loc, optTy.getObjectType(), optTL, ctxt,
[&](SILValue optBuf) {
auto objectBuf = B.createInitEnumDataAddr(loc, optBuf, someDecl, objectTy);
// Evaluate the value in-place into that buffer.
TemporaryInitialization init(objectBuf, CleanupHandle::invalid());
ManagedValue objectResult = generator(SGFContext(&init));
if (!objectResult.isInContext()) {
objectResult.forwardInto(*this, loc, objectBuf);
}
// Finalize the outer optional buffer.
B.createInjectEnumAddr(loc, optBuf, someDecl);
});
}
ManagedValue SILGenFunction::emitExistentialErasure(
SILLocation loc,
CanType concreteFormalType,
const TypeLowering &concreteTL,
const TypeLowering &existentialTL,
ArrayRef<ProtocolConformanceRef> conformances,
SGFContext C,
llvm::function_ref<ManagedValue (SGFContext)> F,
bool allowEmbeddedNSError) {
// Mark the needed conformances as used.
for (auto conformance : conformances)
SGM.useConformance(conformance);
// If we're erasing to the 'Error' type, we might be able to get an NSError
// representation more efficiently.
auto &ctx = getASTContext();
if (ctx.LangOpts.EnableObjCInterop && conformances.size() == 1 &&
conformances[0].getRequirement() == ctx.getErrorDecl() &&
ctx.getNSErrorDecl()) {
auto nsErrorDecl = ctx.getNSErrorDecl();
// If the concrete type is NSError or a subclass thereof, just erase it
// directly.
auto nsErrorType = nsErrorDecl->getDeclaredType()->getCanonicalType();
if (nsErrorType->isExactSuperclassOf(concreteFormalType, nullptr)) {
ManagedValue nsError = F(SGFContext());
if (nsErrorType != concreteFormalType) {
nsError = ManagedValue(B.createUpcast(loc, nsError.getValue(),
getLoweredType(nsErrorType)),
nsError.getCleanup());
}
return emitBridgedToNativeError(loc, nsError);
}
// If the concrete type is known to conform to _BridgedStoredNSError,
// call the _nsError witness getter to extract the NSError directly,
// then just erase the NSError.
if (auto storedNSErrorConformance =
SGM.getConformanceToBridgedStoredNSError(loc, concreteFormalType)) {
auto nsErrorVar = SGM.getNSErrorRequirement(loc);
if (!nsErrorVar) return emitUndef(loc, existentialTL.getLoweredType());
SubstitutionList nsErrorVarSubstitutions;
// Devirtualize. Maybe this should be done implicitly by
// emitPropertyLValue?
if (storedNSErrorConformance->isConcrete()) {
if (auto witnessVar = storedNSErrorConformance->getConcrete()
->getWitness(nsErrorVar, nullptr)) {
nsErrorVar = cast<VarDecl>(witnessVar.getDecl());
nsErrorVarSubstitutions = witnessVar.getSubstitutions();
}
}
auto nativeError = F(SGFContext());
WritebackScope writebackScope(*this);
auto nsError =
emitRValueForPropertyLoad(loc, nativeError, concreteFormalType,
/*super*/ false, nsErrorVar,
nsErrorVarSubstitutions,
AccessSemantics::Ordinary, nsErrorType,
SGFContext())
.getAsSingleValue(*this, loc);
return emitBridgedToNativeError(loc, nsError);
}
// Otherwise, if it's an archetype, try calling the _getEmbeddedNSError()
// witness to try to dig out the embedded NSError. But don't do this
// when we're being called recursively.
if (isa<ArchetypeType>(concreteFormalType) && allowEmbeddedNSError) {
auto contBB = createBasicBlock();
auto isNotPresentBB = createBasicBlock();
auto isPresentBB = createBasicBlock();
// Call swift_stdlib_getErrorEmbeddedNSError to attempt to extract an
// NSError from the value.
auto getEmbeddedNSErrorFn = SGM.getGetErrorEmbeddedNSError(loc);
if (!getEmbeddedNSErrorFn)
return emitUndef(loc, existentialTL.getLoweredType());
Substitution getEmbeddedNSErrorSubstitutions[1] = {
Substitution(concreteFormalType, conformances)
};
ManagedValue concreteValue = F(SGFContext());
ManagedValue potentialNSError =
emitApplyOfLibraryIntrinsic(loc,
getEmbeddedNSErrorFn,
getEmbeddedNSErrorSubstitutions,
{ concreteValue.copy(*this, loc) },
SGFContext())
.getAsSingleValue(*this, loc);
// We're going to consume 'concreteValue' in exactly one branch,
// so kill its cleanup now and recreate it on both branches.
(void) concreteValue.forward(*this);
// Check whether we got an NSError back.
std::pair<EnumElementDecl*, SILBasicBlock*> cases[] = {
{ ctx.getOptionalSomeDecl(), isPresentBB },
{ ctx.getOptionalNoneDecl(), isNotPresentBB }
};
B.createSwitchEnum(loc, potentialNSError.forward(*this),
/*default*/ nullptr, cases);
// If we did get an NSError, emit the existential erasure from that
// NSError.
B.emitBlock(isPresentBB);
SILValue branchArg;
{
// Don't allow cleanups to escape the conditional block.
FullExpr presentScope(Cleanups, CleanupLocation::get(loc));
enterDestroyCleanup(concreteValue.getValue());
// Receive the error value. It's typed as an 'AnyObject' for
// layering reasons, so perform an unchecked cast down to NSError.
SILType anyObjectTy =
potentialNSError.getType().getAnyOptionalObjectType();
SILValue nsError = isPresentBB->createPHIArgument(
anyObjectTy, ValueOwnershipKind::Owned);
nsError = B.createUncheckedRefCast(loc, nsError,
getLoweredType(nsErrorType));
branchArg = emitBridgedToNativeError(loc,
emitManagedRValueWithCleanup(nsError))
.forward(*this);
}
B.createBranch(loc, contBB, branchArg);
// If we did not get an NSError, just directly emit the existential.
// Since this is a recursive call, make sure we don't end up in this
// path again.
B.emitBlock(isNotPresentBB);
{
FullExpr presentScope(Cleanups, CleanupLocation::get(loc));
concreteValue = emitManagedRValueWithCleanup(concreteValue.getValue());
branchArg = emitExistentialErasure(loc, concreteFormalType, concreteTL,
existentialTL, conformances,
SGFContext(),
[&](SGFContext C) {
return concreteValue;
},
/*allowEmbeddedNSError=*/false)
.forward(*this);
}
B.createBranch(loc, contBB, branchArg);
// Continue.
B.emitBlock(contBB);
SILValue existentialResult = contBB->createPHIArgument(
existentialTL.getLoweredType(), ValueOwnershipKind::Owned);
return emitManagedRValueWithCleanup(existentialResult, existentialTL);
}
}
switch (existentialTL.getLoweredType().getObjectType()
.getPreferredExistentialRepresentation(SGM.M, concreteFormalType)) {
case ExistentialRepresentation::None:
llvm_unreachable("not an existential type");
case ExistentialRepresentation::Metatype: {
assert(existentialTL.isLoadable());
SILValue metatype = F(SGFContext()).getUnmanagedValue();
assert(metatype->getType().castTo<AnyMetatypeType>()->getRepresentation()
== MetatypeRepresentation::Thick);
auto upcast =
B.createInitExistentialMetatype(loc, metatype,
existentialTL.getLoweredType(),
conformances);
return ManagedValue::forUnmanaged(upcast);
}
case ExistentialRepresentation::Class: {
assert(existentialTL.isLoadable());
ManagedValue sub = F(SGFContext());
SILValue v = B.createInitExistentialRef(loc,
existentialTL.getLoweredType(),
concreteFormalType,
sub.getValue(),
conformances);
return ManagedValue(v, sub.getCleanup());
}
case ExistentialRepresentation::Boxed: {
// Allocate the existential.
auto *existential = B.createAllocExistentialBox(loc,
existentialTL.getLoweredType(),
concreteFormalType,
conformances);
auto *valueAddr = B.createProjectExistentialBox(loc,
concreteTL.getLoweredType(),
existential);
// Initialize the concrete value in-place.
ExistentialInitialization init(existential, valueAddr, concreteFormalType,
ExistentialRepresentation::Boxed, *this);
ManagedValue mv = F(SGFContext(&init));
if (!mv.isInContext()) {
mv.forwardInto(*this, loc, init.getAddress());
init.finishInitialization(*this);
}
return emitManagedRValueWithCleanup(existential);
}
case ExistentialRepresentation::Opaque: {
// If the concrete value is a pseudogeneric archetype, first erase it to
// its upper bound.
auto anyObjectProto = getASTContext()
.getProtocol(KnownProtocolKind::AnyObject);
auto anyObjectTy = anyObjectProto
? anyObjectProto->getDeclaredType()->getCanonicalType()
: CanType();
auto eraseToAnyObject =
[&, concreteFormalType, F](SGFContext C) -> ManagedValue {
auto concreteValue = F(SGFContext());
auto anyObjectConformance = SGM.SwiftModule
->lookupConformance(concreteFormalType, anyObjectProto, nullptr);
ProtocolConformanceRef buf[] = {
*anyObjectConformance,
};
auto asAnyObject = B.createInitExistentialRef(loc,
SILType::getPrimitiveObjectType(anyObjectTy),
concreteFormalType,
concreteValue.getValue(),
getASTContext().AllocateCopy(buf));
return ManagedValue(asAnyObject, concreteValue.getCleanup());
};
auto concreteTLPtr = &concreteTL;
if (this->F.getLoweredFunctionType()->isPseudogeneric()) {
if (anyObjectTy && concreteFormalType->is<ArchetypeType>()) {
concreteFormalType = anyObjectTy;
concreteTLPtr = &getTypeLowering(anyObjectTy);
F = eraseToAnyObject;
}
}
// Allocate the existential.
SILValue existential =
getBufferForExprResult(loc, existentialTL.getLoweredType(), C);
// Allocate the concrete value inside the container.
SILValue valueAddr = B.createInitExistentialAddr(
loc, existential,
concreteFormalType,
concreteTLPtr->getLoweredType(),
conformances);
// Initialize the concrete value in-place.
InitializationPtr init(
new ExistentialInitialization(existential, valueAddr, concreteFormalType,
ExistentialRepresentation::Opaque,
*this));
ManagedValue mv = F(SGFContext(init.get()));
if (!mv.isInContext()) {
mv.forwardInto(*this, loc, init->getAddress());
init->finishInitialization(*this);
}
return manageBufferForExprResult(existential, existentialTL, C);
}
}
llvm_unreachable("Unhandled ExistentialRepresentation in switch.");
}
ManagedValue SILGenFunction::emitExistentialErasure(
SILLocation loc,
CanType concreteFormalType,
const TypeLowering &concreteTL,
const TypeLowering &existentialTL,
ArrayRef<ProtocolConformanceRef> conformances,
SGFContext C,
llvm::function_ref<ManagedValue (SGFContext)> F,
bool allowEmbeddedNSError) {
// Mark the needed conformances as used.
for (auto conformance : conformances)
SGM.useConformance(conformance);
// If we're erasing to the 'Error' type, we might be able to get an NSError
// representation more efficiently.
auto &ctx = getASTContext();
auto nsError = ctx.getNSErrorDecl();
if (allowEmbeddedNSError && nsError &&
existentialTL.getSemanticType().getSwiftRValueType()->getAnyNominal() ==
ctx.getErrorDecl()) {
// Check whether the concrete type conforms to the _BridgedStoredNSError
// protocol. In that case, call the _nsError witness getter to extract the
// NSError directly.
auto conformance =
SGM.getConformanceToBridgedStoredNSError(loc, concreteFormalType);
CanType nsErrorType =
nsError->getDeclaredInterfaceType()->getCanonicalType();
ProtocolConformanceRef nsErrorConformances[1] = {
ProtocolConformanceRef(SGM.getNSErrorConformanceToError())
};
if (conformance && nsError && SGM.getNSErrorConformanceToError()) {
if (auto witness =
conformance->getWitness(SGM.getNSErrorRequirement(loc), nullptr)) {
// Create a reference to the getter witness.
SILDeclRef getter =
getGetterDeclRef(cast<VarDecl>(witness.getDecl()),
/*isDirectAccessorUse=*/true);
// Compute the substitutions.
ArrayRef<Substitution> substitutions =
concreteFormalType->gatherAllSubstitutions(
SGM.SwiftModule, nullptr);
// Emit the erasure, through the getter to _nsError.
return emitExistentialErasure(
loc, nsErrorType,
getTypeLowering(nsErrorType),
existentialTL,
ctx.AllocateCopy(nsErrorConformances),
C,
[&](SGFContext innerC) -> ManagedValue {
// Call the getter.
return emitGetAccessor(loc, getter, substitutions,
ArgumentSource(loc,
RValue(*this, loc,
concreteFormalType,
F(SGFContext()))),
/*isSuper=*/false,
/*isDirectAccessorUse=*/true,
RValue(), innerC)
.getAsSingleValue(*this, loc);
});
}
}
// Check whether the concrete type is an archetype. If so, call the
// _getEmbeddedNSError() witness to try to dig out the embedded NSError.
if (auto archetypeType = concreteFormalType->getAs<ArchetypeType>()) {
if (std::find(archetypeType->getConformsTo().begin(),
archetypeType->getConformsTo().end(),
ctx.getErrorDecl())
!= archetypeType->getConformsTo().end()) {
auto contBB = createBasicBlock();
auto isNotPresentBB = createBasicBlock();
auto isPresentBB = createBasicBlock();
SILValue existentialResult =
contBB->createBBArg(existentialTL.getLoweredType());
ProtocolConformanceRef trivialErrorConformances[1] = {
ProtocolConformanceRef(ctx.getErrorDecl())
};
Substitution substitutions[1] = {
Substitution(concreteFormalType,
ctx.AllocateCopy(trivialErrorConformances))
};
// Call swift_stdlib_getErrorEmbeddedNSError to attempt to extract an
// NSError from the value.
ManagedValue concreteValue = F(SGFContext());
ManagedValue potentialNSError =
emitApplyOfLibraryIntrinsic(loc,
SGM.getGetErrorEmbeddedNSError(loc),
ctx.AllocateCopy(substitutions),
{ concreteValue },
SGFContext())
.getAsSingleValue(*this, loc);
// Check whether we got an NSError back.
SILValue hasNSError =
emitDoesOptionalHaveValue(loc, potentialNSError.getValue());
B.createCondBranch(loc, hasNSError, isPresentBB, isNotPresentBB);
// If we did get an NSError, emit the existential erasure from that
// NSError.
B.emitBlock(isPresentBB);
SILValue branchArg;
{
// Don't allow cleanups to escape the conditional block.
FullExpr presentScope(Cleanups, CleanupLocation::get(loc));
// Emit the existential erasure from the NSError.
branchArg = emitExistentialErasure(
loc, nsErrorType,
getTypeLowering(nsErrorType),
existentialTL,
ctx.AllocateCopy(nsErrorConformances),
C,
[&](SGFContext innerC) -> ManagedValue {
// Pull the NSError object out of the optional result.
auto &inputTL = getTypeLowering(potentialNSError.getType());
auto nsErrorValue =
emitUncheckedGetOptionalValueFrom(loc, potentialNSError,
inputTL);
// Perform an unchecked cast down to NSError, because it was typed
// as 'AnyObject' for layering reasons.
return ManagedValue(B.createUncheckedRefCast(
loc,
nsErrorValue.getValue(),
getLoweredType(nsErrorType)),
nsErrorValue.getCleanup());
}).forward(*this);
}
B.createBranch(loc, contBB, branchArg);
// If we did not get an NSError, just directly emit the existential
// (recursively).
B.emitBlock(isNotPresentBB);
branchArg = emitExistentialErasure(loc, concreteFormalType, concreteTL,
existentialTL, conformances,
SGFContext(), F,
/*allowEmbeddedNSError=*/false)
.forward(*this);
B.createBranch(loc, contBB, branchArg);
// Continue.
B.emitBlock(contBB);
return emitManagedRValueWithCleanup(existentialResult, existentialTL);
}
}
}
switch (existentialTL.getLoweredType().getObjectType()
.getPreferredExistentialRepresentation(SGM.M, concreteFormalType)) {
case ExistentialRepresentation::None:
llvm_unreachable("not an existential type");
case ExistentialRepresentation::Metatype: {
assert(existentialTL.isLoadable());
SILValue metatype = F(SGFContext()).getUnmanagedValue();
assert(metatype->getType().castTo<AnyMetatypeType>()->getRepresentation()
== MetatypeRepresentation::Thick);
auto upcast =
B.createInitExistentialMetatype(loc, metatype,
existentialTL.getLoweredType(),
conformances);
return ManagedValue::forUnmanaged(upcast);
}
case ExistentialRepresentation::Class: {
assert(existentialTL.isLoadable());
ManagedValue sub = F(SGFContext());
SILValue v = B.createInitExistentialRef(loc,
existentialTL.getLoweredType(),
concreteFormalType,
sub.getValue(),
conformances);
return ManagedValue(v, sub.getCleanup());
}
case ExistentialRepresentation::Boxed: {
// Allocate the existential.
auto *existential = B.createAllocExistentialBox(loc,
existentialTL.getLoweredType(),
concreteFormalType,
conformances);
auto *valueAddr = B.createProjectExistentialBox(loc,
concreteTL.getLoweredType(),
existential);
// Initialize the concrete value in-place.
InitializationPtr init(
new ExistentialInitialization(existential, valueAddr, concreteFormalType,
ExistentialRepresentation::Boxed,
*this));
ManagedValue mv = F(SGFContext(init.get()));
if (!mv.isInContext()) {
mv.forwardInto(*this, loc, init->getAddress());
init->finishInitialization(*this);
}
return emitManagedRValueWithCleanup(existential);
}
case ExistentialRepresentation::Opaque: {
// Allocate the existential.
SILValue existential =
getBufferForExprResult(loc, existentialTL.getLoweredType(), C);
// Allocate the concrete value inside the container.
SILValue valueAddr = B.createInitExistentialAddr(
loc, existential,
concreteFormalType,
concreteTL.getLoweredType(),
conformances);
// Initialize the concrete value in-place.
InitializationPtr init(
new ExistentialInitialization(existential, valueAddr, concreteFormalType,
ExistentialRepresentation::Opaque,
*this));
ManagedValue mv = F(SGFContext(init.get()));
if (!mv.isInContext()) {
mv.forwardInto(*this, loc, init->getAddress());
init->finishInitialization(*this);
}
return manageBufferForExprResult(existential, existentialTL, C);
}
}
}
ManagedValue SILGenFunction::emitExistentialErasure(
SILLocation loc,
CanType concreteFormalType,
const TypeLowering &concreteTL,
const TypeLowering &existentialTL,
const ArrayRef<ProtocolConformance *> &conformances,
SGFContext C,
llvm::function_ref<ManagedValue (SGFContext)> F) {
// Mark the needed conformances as used.
for (auto *conformance : conformances)
SGM.useConformance(conformance);
switch (existentialTL.getLoweredType().getObjectType()
.getPreferredExistentialRepresentation(SGM.M, concreteFormalType)) {
case ExistentialRepresentation::None:
llvm_unreachable("not an existential type");
case ExistentialRepresentation::Metatype: {
assert(existentialTL.isLoadable());
SILValue metatype = F(SGFContext()).getUnmanagedValue();
assert(metatype.getType().castTo<AnyMetatypeType>()->getRepresentation()
== MetatypeRepresentation::Thick);
auto upcast =
B.createInitExistentialMetatype(loc, metatype,
existentialTL.getLoweredType(),
conformances);
return ManagedValue::forUnmanaged(upcast);
}
case ExistentialRepresentation::Class: {
assert(existentialTL.isLoadable());
ManagedValue sub = F(SGFContext());
SILValue v = B.createInitExistentialRef(loc,
existentialTL.getLoweredType(),
concreteFormalType,
sub.getValue(),
conformances);
return ManagedValue(v, sub.getCleanup());
}
case ExistentialRepresentation::Boxed: {
// Allocate the existential.
auto box = B.createAllocExistentialBox(loc,
existentialTL.getLoweredType(),
concreteFormalType,
concreteTL.getLoweredType(),
conformances);
auto existential = box->getExistentialResult();
auto valueAddr = box->getValueAddressResult();
// Initialize the concrete value in-place.
InitializationPtr init(
new ExistentialInitialization(existential, valueAddr, concreteFormalType,
ExistentialRepresentation::Boxed,
*this));
ManagedValue mv = F(SGFContext(init.get()));
if (!mv.isInContext()) {
mv.forwardInto(*this, loc, init->getAddress());
init->finishInitialization(*this);
}
return emitManagedRValueWithCleanup(existential);
}
case ExistentialRepresentation::Opaque: {
// Allocate the existential.
SILValue existential =
getBufferForExprResult(loc, existentialTL.getLoweredType(), C);
// Allocate the concrete value inside the container.
SILValue valueAddr = B.createInitExistentialAddr(
loc, existential,
concreteFormalType,
concreteTL.getLoweredType(),
conformances);
// Initialize the concrete value in-place.
InitializationPtr init(
new ExistentialInitialization(existential, valueAddr, concreteFormalType,
ExistentialRepresentation::Opaque,
*this));
ManagedValue mv = F(SGFContext(init.get()));
if (!mv.isInContext()) {
mv.forwardInto(*this, loc, init->getAddress());
init->finishInitialization(*this);
}
return manageBufferForExprResult(existential, existentialTL, C);
}
}
}
