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SILGenConvert.cpp
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//===--- SILGenConvert.cpp - Type Conversion Routines ---------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "SILGen.h"
#include "ArgumentSource.h"
#include "Conversion.h"
#include "Initialization.h"
#include "LValue.h"
#include "RValue.h"
#include "Scope.h"
#include "SwitchEnumBuilder.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/Decl.h"
#include "swift/AST/ProtocolConformance.h"
#include "swift/AST/SubstitutionMap.h"
#include "swift/AST/Types.h"
#include "swift/Basic/SourceManager.h"
#include "swift/Basic/type_traits.h"
#include "swift/SIL/SILArgument.h"
#include "swift/SIL/TypeLowering.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/SaveAndRestore.h"
#include "llvm/Support/raw_ostream.h"
using namespace swift;
using namespace Lowering;
// 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.getOptionalObjectType();
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());
return B.createEnum(loc, objectResult, someDecl, optTy);
}
// 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.ensurePlusOne(*this, loc)
.forwardInto(*this, loc, objectBuf);
}
// Finalize the outer optional buffer.
B.createInjectEnumAddr(loc, optBuf, someDecl);
});
}
void SILGenFunction::emitInjectOptionalValueInto(SILLocation loc,
ArgumentSource &&value,
SILValue dest,
const TypeLowering &optTL) {
SILType optType = optTL.getLoweredType();
assert(dest->getType() == optType.getAddressType());
auto loweredPayloadTy = optType.getOptionalObjectType();
assert(loweredPayloadTy);
// Project out the payload area.
auto someDecl = getASTContext().getOptionalSomeDecl();
auto destPayload =
B.createInitEnumDataAddr(loc, dest, someDecl,
loweredPayloadTy.getAddressType());
// Emit the value into the payload area.
TemporaryInitialization emitInto(destPayload, CleanupHandle::invalid());
std::move(value).forwardInto(*this, &emitInto);
// Inject the tag.
B.createInjectEnumAddr(loc, dest, someDecl);
}
void SILGenFunction::emitInjectOptionalNothingInto(SILLocation loc,
SILValue dest,
const TypeLowering &optTL) {
assert(optTL.getLoweredType().getOptionalObjectType());
B.createInjectEnumAddr(loc, dest, getASTContext().getOptionalNoneDecl());
}
/// Return a value for an optional ".None" of the specified type. This only
/// works for loadable enum types.
SILValue SILGenFunction::getOptionalNoneValue(SILLocation loc,
const TypeLowering &optTL) {
assert((optTL.isLoadable() || !silConv.useLoweredAddresses()) &&
"Address-only optionals cannot use this");
assert(optTL.getLoweredType().getOptionalObjectType());
return B.createEnum(loc, SILValue(), getASTContext().getOptionalNoneDecl(),
optTL.getLoweredType());
}
/// Return a value for an optional ".Some(x)" of the specified type. This only
/// works for loadable enum types.
ManagedValue SILGenFunction::
getOptionalSomeValue(SILLocation loc, ManagedValue value,
const TypeLowering &optTL) {
assert((optTL.isLoadable() || !silConv.useLoweredAddresses()) &&
"Address-only optionals cannot use this");
SILType optType = optTL.getLoweredType();
auto formalOptType = optType.getASTType();
(void)formalOptType;
assert(formalOptType.getOptionalObjectType());
auto someDecl = getASTContext().getOptionalSomeDecl();
return B.createEnum(loc, value, someDecl, optTL.getLoweredType());
}
auto SILGenFunction::emitSourceLocationArgs(SourceLoc sourceLoc,
SILLocation emitLoc)
-> SourceLocArgs {
auto &ctx = getASTContext();
std::string filename = "";
unsigned line = 0;
unsigned column = 0;
if (sourceLoc.isValid()) {
filename = getMagicFileIDString(sourceLoc);
std::tie(line, column) =
ctx.SourceMgr.getPresumedLineAndColumnForLoc(sourceLoc);
}
bool isASCII = true;
for (unsigned char c : filename) {
if (c > 127) {
isASCII = false;
break;
}
}
auto wordTy = SILType::getBuiltinWordType(ctx);
auto i1Ty = SILType::getBuiltinIntegerType(1, ctx);
SourceLocArgs result;
SILValue literal = B.createStringLiteral(emitLoc, StringRef(filename),
StringLiteralInst::Encoding::UTF8);
result.filenameStartPointer =
ManagedValue::forObjectRValueWithoutOwnership(literal);
// File length
literal = B.createIntegerLiteral(emitLoc, wordTy, filename.size());
result.filenameLength =
ManagedValue::forObjectRValueWithoutOwnership(literal);
// File is ascii
literal = B.createIntegerLiteral(emitLoc, i1Ty, isASCII);
result.filenameIsAscii =
ManagedValue::forObjectRValueWithoutOwnership(literal);
// Line
literal = B.createIntegerLiteral(emitLoc, wordTy, line);
result.line = ManagedValue::forObjectRValueWithoutOwnership(literal);
// Column
literal = B.createIntegerLiteral(emitLoc, wordTy, column);
result.column = ManagedValue::forObjectRValueWithoutOwnership(literal);
return result;
}
ManagedValue
SILGenFunction::emitPreconditionOptionalHasValue(SILLocation loc,
ManagedValue optional,
bool isImplicitUnwrap) {
// Generate code to the optional is present, and if not, abort with a message
// (provided by the stdlib).
SILBasicBlock *contBB = createBasicBlock();
SILBasicBlock *failBB = createBasicBlock();
bool hadCleanup = optional.hasCleanup();
bool hadLValue = optional.isLValue();
auto someDecl = getASTContext().getOptionalSomeDecl();
auto noneDecl = getASTContext().getOptionalNoneDecl();
// If we have an object, make sure the object is at +1. All switch_enum of
// objects is done at +1.
bool isAddress = optional.getType().isAddress();
SwitchEnumInst *switchEnum = nullptr;
if (isAddress) {
// We forward in the creation routine for
// unchecked_take_enum_data_addr. switch_enum_addr is a +0 operation.
B.createSwitchEnumAddr(loc, optional.getValue(),
/*defaultDest*/ nullptr,
{{someDecl, contBB}, {noneDecl, failBB}});
} else {
optional = optional.ensurePlusOne(*this, loc);
hadCleanup = true;
hadLValue = false;
switchEnum = B.createSwitchEnum(loc, optional.forward(*this),
/*defaultDest*/ nullptr,
{{someDecl, contBB}, {noneDecl, failBB}});
}
B.emitBlock(failBB);
// Call the standard library implementation of _diagnoseUnexpectedNilOptional.
if (auto diagnoseFailure =
getASTContext().getDiagnoseUnexpectedNilOptional()) {
auto args = emitSourceLocationArgs(loc.getSourceLoc(), loc);
auto i1Ty = SILType::getBuiltinIntegerType(1, getASTContext());
auto isImplicitUnwrapLiteral =
B.createIntegerLiteral(loc, i1Ty, isImplicitUnwrap);
auto isImplicitUnwrapValue =
ManagedValue::forObjectRValueWithoutOwnership(isImplicitUnwrapLiteral);
emitApplyOfLibraryIntrinsic(loc, diagnoseFailure, SubstitutionMap(),
{
args.filenameStartPointer,
args.filenameLength,
args.filenameIsAscii,
args.line,
isImplicitUnwrapValue
},
SGFContext());
}
B.createUnreachable(ArtificialUnreachableLocation());
B.clearInsertionPoint();
B.emitBlock(contBB);
ManagedValue result;
if (isAddress) {
SILType payloadType = optional.getType().getOptionalObjectType();
result =
B.createUncheckedTakeEnumDataAddr(loc, optional, someDecl, payloadType);
} else {
result = B.createOptionalSomeResult(switchEnum);
}
if (hadCleanup) {
return result;
}
if (hadLValue) {
return ManagedValue::forLValue(result.forward(*this));
}
return ManagedValue::forBorrowedRValue(result.forward(*this));
}
SILValue SILGenFunction::emitDoesOptionalHaveValue(SILLocation loc,
SILValue addrOrValue) {
auto boolTy = SILType::getBuiltinIntegerType(1, getASTContext());
SILValue yes = B.createIntegerLiteral(loc, boolTy, 1);
SILValue no = B.createIntegerLiteral(loc, boolTy, 0);
auto someDecl = getASTContext().getOptionalSomeDecl();
if (addrOrValue->getType().isAddress())
return B.createSelectEnumAddr(loc, addrOrValue, boolTy, no,
std::make_pair(someDecl, yes));
return B.createSelectEnum(loc, addrOrValue, boolTy, no,
std::make_pair(someDecl, yes));
}
ManagedValue SILGenFunction::emitCheckedGetOptionalValueFrom(SILLocation loc,
ManagedValue src,
bool isImplicitUnwrap,
const TypeLowering &optTL,
SGFContext C) {
// TODO: Make this take optTL.
return emitPreconditionOptionalHasValue(loc, src, isImplicitUnwrap);
}
ManagedValue SILGenFunction::emitUncheckedGetOptionalValueFrom(
SILLocation loc, ManagedValue addrOrValue, const TypeLowering &optTL,
SGFContext C) {
SILType origPayloadTy = addrOrValue.getType().getOptionalObjectType();
auto someDecl = getASTContext().getOptionalSomeDecl();
// Take the payload from the optional.
if (!addrOrValue.getType().isAddress()) {
return B.createUncheckedEnumData(loc, addrOrValue, someDecl);
}
// Cheat a bit in the +0 case--UncheckedTakeEnumData will never actually
// invalidate an Optional enum value. This is specific to optionals.
ManagedValue payload = B.createUncheckedTakeEnumDataAddr(
loc, addrOrValue, someDecl, origPayloadTy);
if (!optTL.isLoadable())
return payload;
// If we do not have a cleanup on our address, use a load_borrow.
if (!payload.hasCleanup()) {
return B.createLoadBorrow(loc, payload);
}
// Otherwise, perform a load take.
return B.createLoadTake(loc, payload);
}
ManagedValue
SILGenFunction::emitOptionalSome(SILLocation loc, SILType optTy,
ValueProducerRef produceValue,
SGFContext C) {
// If the conversion is a bridging conversion from an optional type,
// do a bridging conversion from the non-optional type instead.
// TODO: should this be a general thing for all conversions?
if (auto optInit = C.getAsConversion()) {
const auto &optConversion = optInit->getConversion();
if (optConversion.isBridging()) {
auto sourceValueType =
optConversion.getBridgingSourceType().getOptionalObjectType();
assert(sourceValueType);
if (auto valueConversion =
optConversion.adjustForInitialOptionalConversions(sourceValueType)){
return optInit->emitWithAdjustedConversion(*this, loc, *valueConversion,
produceValue);
}
}
}
auto &optTL = getTypeLowering(optTy);
// If the type is loadable or we're not lowering address-only types
// in SILGen, use a simple scalar pattern.
if (!silConv.useLoweredAddresses() || optTL.isLoadable()) {
auto value = produceValue(*this, loc, SGFContext());
return getOptionalSomeValue(loc, value, optTL);
}
// Otherwise, emit into memory, preferably into an address from
// the context.
// Get an address to emit into.
SILValue optAddr = getBufferForExprResult(loc, optTy, C);
auto someDecl = getASTContext().getOptionalSomeDecl();
auto valueTy = optTy.getOptionalObjectType();
auto &valueTL = getTypeLowering(valueTy);
// Project the value buffer within the address.
SILValue valueAddr =
B.createInitEnumDataAddr(loc, optAddr, someDecl,
valueTy.getAddressType());
// Emit into the value buffer.
auto valueInit = useBufferAsTemporary(valueAddr, valueTL);
ManagedValue value = produceValue(*this, loc, SGFContext(valueInit.get()));
if (!value.isInContext()) {
valueInit->copyOrInitValueInto(*this, loc, value, /*isInit*/ true);
valueInit->finishInitialization(*this);
}
// Kill the cleanup on the value.
valueInit->getManagedAddress().forward(*this);
// Finish the optional.
B.createInjectEnumAddr(loc, optAddr, someDecl);
return manageBufferForExprResult(optAddr, optTL, C);
}
/// Emit an optional-to-optional transformation.
ManagedValue
SILGenFunction::emitOptionalToOptional(SILLocation loc,
ManagedValue input,
SILType resultTy,
ValueTransformRef transformValue,
SGFContext C) {
auto &Ctx = getASTContext();
// If the input is known to be 'none' just emit a 'none' value of the right
// result type right away.
auto &resultTL = getTypeLowering(resultTy);
if (auto *EI = dyn_cast<EnumInst>(input.getValue())) {
if (EI->getElement() == Ctx.getOptionalNoneDecl()) {
if (!(resultTL.isAddressOnly() && silConv.useLoweredAddresses())) {
SILValue none = B.createEnum(loc, SILValue(), EI->getElement(),
resultTy);
return emitManagedRValueWithCleanup(none);
}
}
}
// Otherwise perform a dispatch.
auto contBB = createBasicBlock();
auto isNotPresentBB = createBasicBlock();
auto isPresentBB = createBasicBlock();
// All conversions happen at +1.
input = input.ensurePlusOne(*this, loc);
SwitchEnumBuilder SEBuilder(B, loc, input);
SILType noOptResultTy = resultTy.getOptionalObjectType();
assert(noOptResultTy);
// Create a temporary for the output optional.
//
// If the result is address-only, we need to return something in memory,
// otherwise the result is the BBArgument in the merge point.
// TODO: use the SGFContext passed in.
ManagedValue resultAddress;
bool addressOnly = resultTL.isAddressOnly() && silConv.useLoweredAddresses();
if (addressOnly) {
resultAddress = emitManagedBufferWithCleanup(
emitTemporaryAllocation(loc, resultTy), resultTL);
}
ValueOwnershipKind resultOwnership = OwnershipKind::Any;
SEBuilder.addOptionalSomeCase(
isPresentBB, contBB, [&](ManagedValue input, SwitchCaseFullExpr &&scope) {
// If we have an address only type, we want to match the old behavior of
// transforming the underlying type instead of the optional type. This
// ensures that we use the more efficient non-generic code paths when
// possible.
if (getTypeLowering(input.getType()).isAddressOnly() &&
silConv.useLoweredAddresses()) {
auto *someDecl = Ctx.getOptionalSomeDecl();
input = B.createUncheckedTakeEnumDataAddr(
loc, input, someDecl, input.getType().getOptionalObjectType());
}
ManagedValue result = transformValue(*this, loc, input, noOptResultTy,
SGFContext());
resultOwnership = result.getValue()->getOwnershipKind();
if (!addressOnly) {
SILValue some = B.createOptionalSome(loc, result).forward(*this);
return scope.exitAndBranch(loc, some);
}
RValue R(*this, loc, noOptResultTy.getASTType(), result);
ArgumentSource resultValueRV(loc, std::move(R));
emitInjectOptionalValueInto(loc, std::move(resultValueRV),
resultAddress.getValue(), resultTL);
return scope.exitAndBranch(loc);
});
SEBuilder.addOptionalNoneCase(
isNotPresentBB, contBB,
[&](ManagedValue input, SwitchCaseFullExpr &&scope) {
if (!addressOnly) {
SILValue none =
B.createManagedOptionalNone(loc, resultTy).forward(*this);
return scope.exitAndBranch(loc, none);
}
emitInjectOptionalNothingInto(loc, resultAddress.getValue(), resultTL);
return scope.exitAndBranch(loc);
});
std::move(SEBuilder).emit();
B.emitBlock(contBB);
if (addressOnly)
return resultAddress;
// This phi's ownership is derived from the transformed value's
// ownership, not the input ownership. Transformation can convert a value with
// no ownership to an owned value.
return B.createPhi(resultTL.getLoweredType(), resultOwnership);
}
SILGenFunction::OpaqueValueRAII::~OpaqueValueRAII() {
auto entry = Self.OpaqueValues.find(OpaqueValue);
assert(entry != Self.OpaqueValues.end());
Self.OpaqueValues.erase(entry);
}
RValue
SILGenFunction::emitPointerToPointer(SILLocation loc,
ManagedValue input,
CanType inputType,
CanType outputType,
SGFContext C) {
auto converter = getASTContext().getConvertPointerToPointerArgument();
auto origValue = input;
if (silConv.useLoweredAddresses()) {
// The generic function currently always requires indirection, but pointers
// are always loadable.
auto origBuf = emitTemporaryAllocation(loc, input.getType());
B.emitStoreValueOperation(loc, input.forward(*this), origBuf,
StoreOwnershipQualifier::Init);
origValue = emitManagedBufferWithCleanup(origBuf);
}
// Invoke the conversion intrinsic to convert to the destination type.
auto *M = SGM.M.getSwiftModule();
auto *proto = getPointerProtocol();
auto firstSubMap = inputType->getContextSubstitutionMap(M, proto);
auto secondSubMap = outputType->getContextSubstitutionMap(M, proto);
auto genericSig = converter->getGenericSignature();
auto subMap =
SubstitutionMap::combineSubstitutionMaps(firstSubMap,
secondSubMap,
CombineSubstitutionMaps::AtIndex,
1, 0,
genericSig);
return emitApplyOfLibraryIntrinsic(loc, converter, subMap, origValue, C);
}
namespace {
/// This is an initialization for an address-only existential in memory.
class ExistentialInitialization final : public SingleBufferInitialization {
SILValue existential;
CanType concreteFormalType;
ArrayRef<ProtocolConformanceRef> conformances;
ExistentialRepresentation repr;
// Initialized lazily when the address for initialization is demanded.
SILValue concreteBuffer;
CleanupHandle deinitExistentialCleanup;
public:
/// \param existential The existential container
/// \param concreteFormalType Unlowered AST type of value
/// \param conformances Conformances for concrete type to existential's
/// protocols
ExistentialInitialization(SILGenFunction &SGF,
SILValue existential,
CanType concreteFormalType,
ArrayRef<ProtocolConformanceRef> conformances,
ExistentialRepresentation repr)
: existential(existential),
concreteFormalType(concreteFormalType),
conformances(conformances),
repr(repr)
{
assert(existential->getType().isAddress());
// Create a cleanup to deallocate an allocated but uninitialized concrete
// type buffer.
// It won't be activated until that buffer is formed later, though.
deinitExistentialCleanup =
SGF.enterDeinitExistentialCleanup(CleanupState::Dormant,
existential, concreteFormalType, repr);
}
SILValue getAddressForInPlaceInitialization(SILGenFunction &SGF,
SILLocation loc) override {
// Create the buffer when needed, because in some cases the type may
// be the opened type from another existential that hasn't been opened
// at the point the existential destination was formed.
assert(!concreteBuffer && "concrete buffer already formed?!");
auto concreteLoweredType =
SGF.getLoweredType(AbstractionPattern::getOpaque(), concreteFormalType);
switch (repr) {
case ExistentialRepresentation::Opaque: {
concreteBuffer = SGF.B.createInitExistentialAddr(loc, existential,
concreteFormalType,
concreteLoweredType.getAddressType(),
conformances);
break;
}
case ExistentialRepresentation::Boxed: {
auto box = SGF.B.createAllocExistentialBox(loc,
existential->getType().getObjectType(),
concreteFormalType,
conformances);
concreteBuffer = SGF.B.createProjectExistentialBox(loc,
concreteLoweredType.getAddressType(),
box);
SGF.B.createStore(loc, box, existential,
StoreOwnershipQualifier::Init);
break;
}
case ExistentialRepresentation::Class:
case ExistentialRepresentation::Metatype:
case ExistentialRepresentation::None:
llvm_unreachable("not supported");
}
// Activate the cleanup to deallocate the buffer we just allocated, should
SGF.Cleanups.setCleanupState(deinitExistentialCleanup,
CleanupState::Active);
return concreteBuffer;
}
bool isInPlaceInitializationOfGlobal() const override {
return isa_and_nonnull<GlobalAddrInst>(existential);
}
void finishInitialization(SILGenFunction &SGF) override {
SingleBufferInitialization::finishInitialization(SGF);
// We've fully initialized the existential by this point, so we can
// retire the partial cleanup.
SGF.Cleanups.setCleanupState(deinitExistentialCleanup,
CleanupState::Dead);
}
};
} // end anonymous namespace
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()) {
// If the concrete type is NSError or a subclass thereof, just erase it
// directly.
auto nsErrorType = ctx.getNSErrorType()->getCanonicalType();
if (nsErrorType->isExactSuperclassOf(concreteFormalType)) {
ManagedValue nsError = F(SGFContext());
if (nsErrorType != concreteFormalType) {
nsError = B.createUpcast(loc, nsError, getLoweredType(nsErrorType));
}
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.
auto storedNSErrorConformance =
SGM.getConformanceToBridgedStoredNSError(loc, concreteFormalType);
if (storedNSErrorConformance) {
auto nsErrorVar = SGM.getNSErrorRequirement(loc);
if (!nsErrorVar) return emitUndef(existentialTL.getLoweredType());
SubstitutionMap nsErrorVarSubstitutions;
// Devirtualize. Maybe this should be done implicitly by
// emitPropertyLValue?
if (storedNSErrorConformance.isConcrete()) {
if (auto normal = dyn_cast<NormalProtocolConformance>(
storedNSErrorConformance.getConcrete())) {
if (auto witnessVar = normal->getWitness(nsErrorVar)) {
nsErrorVar = cast<VarDecl>(witnessVar.getDecl());
nsErrorVarSubstitutions = witnessVar.getSubstitutions();
}
}
}
ManagedValue nativeError = F(SGFContext());
FormalEvaluationScope writebackScope(*this);
ManagedValue nsError =
emitRValueForStorageLoad(
loc, nativeError, concreteFormalType,
/*super*/ false, nsErrorVar, PreparedArguments(),
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(existentialTL.getLoweredType());
auto getEmbeddedNSErrorSubstitutions =
SubstitutionMap::getProtocolSubstitutions(ctx.getErrorDecl(),
concreteFormalType,
conformances[0]);
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 }
};
auto *switchEnum =
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(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.
auto nsError = B.createOptionalSomeResult(switchEnum);
nsError = B.createUncheckedRefCast(loc, nsError,
getLoweredType(nsErrorType));
branchArg = emitBridgedToNativeError(loc, 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(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(), OwnershipKind::Owned);
return emitManagedRValueWithCleanup(existentialResult, existentialTL);
}
}
switch (existentialTL.getLoweredType().getObjectType()
.getPreferredExistentialRepresentation(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::forObjectRValueWithoutOwnership(upcast);
}
case ExistentialRepresentation::Class: {
assert(existentialTL.isLoadable());
ManagedValue sub = F(SGFContext());
assert(concreteFormalType->isBridgeableObjectType());
return B.createInitExistentialRef(loc, existentialTL.getLoweredType(),
concreteFormalType, sub, conformances);
}
case ExistentialRepresentation::Boxed: {
// We defer allocation of the box to when the address is demanded.
// Create a stack slot to hold the box once it's allocated.
SILValue boxValue;
auto buf = B.bufferForExpr(
loc, existentialTL.getLoweredType(), existentialTL, C,
[&](SILValue existential) {
// Initialize the existential in-place.
ExistentialInitialization init(*this, existential,
concreteFormalType,
conformances,
ExistentialRepresentation::Boxed);
ManagedValue mv = F(SGFContext(&init));
if (!mv.isInContext()) {
init.copyOrInitValueInto(*this, loc, mv.ensurePlusOne(*this, loc),
/*init*/ true);
init.finishInitialization(*this);
}
});
if (buf.isInContext()) {
return buf;
}
auto value = B.createLoad(loc, buf.forward(*this),
LoadOwnershipQualifier::Take);
return emitManagedRValueWithCleanup(value);
}
case ExistentialRepresentation::Opaque: {
// If the concrete value is a pseudogeneric archetype, first erase it to
// its upper bound.
auto anyObjectTy = getASTContext().getAnyObjectType();
auto eraseToAnyObject =
[&, concreteFormalType, F](SGFContext C) -> ManagedValue {
auto concreteValue = F(SGFContext());
assert(concreteFormalType->isBridgeableObjectType());
auto *M = SGM.M.getSwiftModule();
auto conformances = M->collectExistentialConformances(
concreteFormalType, anyObjectTy);
return B.createInitExistentialRef(
loc, SILType::getPrimitiveObjectType(anyObjectTy), concreteFormalType,
concreteValue, conformances);
};
if (this->F.getLoweredFunctionType()->isPseudogeneric()) {
if (anyObjectTy && concreteFormalType->is<ArchetypeType>()) {
concreteFormalType = anyObjectTy;
F = eraseToAnyObject;
}
}
if (!silConv.useLoweredAddresses()) {
// We should never create new buffers just for init_existential under
// opaque values mode: This is a case of an opaque value that we can
// "treat" as a by-value one
ManagedValue sub = F(SGFContext());
return B.createInitExistentialValue(
loc, existentialTL.getLoweredType(), concreteFormalType,
sub, conformances);
}
// Allocate the existential.
return B.bufferForExpr(
loc, existentialTL.getLoweredType(), existentialTL, C,
[&](SILValue existential) {
// Initialize the existential in-place.
ExistentialInitialization init(*this, existential,
concreteFormalType,
conformances,
ExistentialRepresentation::Opaque);
ManagedValue mv = F(SGFContext(&init));
if (!mv.isInContext()) {
init.copyOrInitValueInto(*this, loc, mv.ensurePlusOne(*this, loc),
/*init*/ true);
init.finishInitialization(*this);
}
});
}
}
llvm_unreachable("Unhandled ExistentialRepresentation in switch.");
}
ManagedValue SILGenFunction::emitClassMetatypeToObject(SILLocation loc,
ManagedValue v,
SILType resultTy) {
SILValue value = v.getUnmanagedValue();
// Convert the metatype to objc representation.
auto metatypeTy = value->getType().castTo<MetatypeType>();
auto objcMetatypeTy = CanMetatypeType::get(metatypeTy.getInstanceType(),
MetatypeRepresentation::ObjC);
value = B.createThickToObjCMetatype(loc, value,
SILType::getPrimitiveObjectType(objcMetatypeTy));
// Convert to an object reference.
value = B.createObjCMetatypeToObject(loc, value, resultTy);
return emitManagedRValueWithCleanup(value);
}
ManagedValue SILGenFunction::emitExistentialMetatypeToObject(SILLocation loc,
ManagedValue v,
SILType resultTy) {
SILValue value = v.getUnmanagedValue();
// Convert the metatype to objc representation.
auto metatypeTy = value->getType().castTo<ExistentialMetatypeType>();
auto objcMetatypeTy = CanExistentialMetatypeType::get(
metatypeTy.getInstanceType(),
MetatypeRepresentation::ObjC);
value = B.createThickToObjCMetatype(loc, value,
SILType::getPrimitiveObjectType(objcMetatypeTy));
// Convert to an object reference.
value = B.createObjCExistentialMetatypeToObject(loc, value, resultTy);
return emitManagedRValueWithCleanup(value);
}
ManagedValue SILGenFunction::emitProtocolMetatypeToObject(SILLocation loc,
CanType inputTy,
SILType resultTy) {
auto protocolType = inputTy->castTo<MetatypeType>()->getInstanceType();
if (auto existential = protocolType->getAs<ExistentialType>())
protocolType = existential->getConstraintType();
ProtocolDecl *protocol = protocolType->castTo<ProtocolType>()->getDecl();
SILValue value = B.createObjCProtocol(loc, protocol, resultTy);
// Protocol objects, despite being global objects, inherit default reference
// counting semantics from NSObject, so we need to retain the protocol
// reference when we use it to prevent it being released and attempting to
// deallocate itself. It doesn't matter if we ever actually clean up that
// retain though.
value = B.createCopyValue(loc, value);
return emitManagedRValueWithCleanup(value);
}
ManagedValue
SILGenFunction::emitOpenExistential(
SILLocation loc,
ManagedValue existentialValue,
SILType loweredOpenedType,
AccessKind accessKind) {
assert(isInFormalEvaluationScope());
SILType existentialType = existentialValue.getType();
switch (existentialType.getPreferredExistentialRepresentation()) {
case ExistentialRepresentation::Opaque: {
// With CoW existentials we can't consume the boxed value inside of
// the existential. (We could only do so after a uniqueness check on
// the box holding the value).
if (existentialType.isAddress()) {
OpenedExistentialAccess allowedAccess =
getOpenedExistentialAccessFor(accessKind);
if (!loweredOpenedType.isAddress()) {
assert(!silConv.useLoweredAddresses() &&
"Non-address loweredOpenedType is only allowed under opaque "
"value mode");
loweredOpenedType = loweredOpenedType.getAddressType();
}
SILValue archetypeValue =
B.createOpenExistentialAddr(loc, existentialValue.getValue(),
loweredOpenedType, allowedAccess);
return ManagedValue::forBorrowedAddressRValue(archetypeValue);
} else {
// borrow the existential and return an unmanaged opened value.
return B.createOpenExistentialValue(
loc, existentialValue, loweredOpenedType);
}
}
case ExistentialRepresentation::Metatype:
assert(existentialType.isObject());
return B.createOpenExistentialMetatype(
loc, existentialValue, loweredOpenedType);
case ExistentialRepresentation::Class:
assert(existentialType.isObject());
return B.createOpenExistentialRef(loc, existentialValue, loweredOpenedType);
case ExistentialRepresentation::Boxed:
if (existentialType.isAddress()) {
existentialValue = emitLoad(loc, existentialValue.getValue(),
getTypeLowering(existentialType),
SGFContext::AllowGuaranteedPlusZero,
IsNotTake);
}
existentialType = existentialValue.getType();
assert(existentialType.isObject());
if (loweredOpenedType.isAddress()) {
return B.createOpenExistentialBox(loc, existentialValue,
loweredOpenedType);
} else {
assert(!silConv.useLoweredAddresses());
return B.createOpenExistentialBoxValue(
loc, existentialValue, loweredOpenedType);
}
case ExistentialRepresentation::None:
llvm_unreachable("not existential");
}
llvm_unreachable("covered switch");