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//===--- SILGenBridging.cpp - SILGen for bridging to Clang ASTs -----------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#include "SILGenFunction.h"
#include "RValue.h"
#include "Scope.h"
#include "swift/AST/ArchetypeBuilder.h"
#include "swift/AST/AST.h"
#include "swift/AST/DiagnosticsSIL.h"
#include "swift/AST/ForeignErrorConvention.h"
#include "swift/AST/ParameterList.h"
#include "swift/Basic/Fallthrough.h"
#include "swift/SIL/SILArgument.h"
#include "swift/SIL/SILUndef.h"
#include "swift/SIL/TypeLowering.h"
using namespace swift;
using namespace Lowering;
/// Bridge the given Swift value to its corresponding Objective-C
/// object, using the appropriate witness for the
/// _ObjectiveCBridgeable._bridgeToObjectiveC requirement.
static Optional<ManagedValue>
emitBridgeNativeToObjectiveC(SILGenFunction &gen,
SILLocation loc,
ManagedValue swiftValue,
ProtocolConformance *conformance) {
// Dig out the nominal type we're bridging from.
Type swiftValueType = swiftValue.getSwiftType()->getRValueType();
// Find the _bridgeToObjectiveC requirement.
auto requirement = gen.SGM.getBridgeToObjectiveCRequirement(loc);
if (!requirement) return None;
// Retrieve the _bridgeToObjectiveC witness.
auto witness = conformance->getWitness(requirement, nullptr);
assert(witness);
// Determine the type we're bridging to.
auto objcTypeReq = gen.SGM.getBridgedObjectiveCTypeRequirement(loc);
if (!objcTypeReq) return None;
Type objcType =
conformance->getTypeWitness(objcTypeReq, nullptr).getReplacement();
assert(objcType);
// Create a reference to the witness.
SILDeclRef witnessConstant(witness.getDecl());
auto witnessRef = gen.emitGlobalFunctionRef(loc, witnessConstant);
// Determine the substitutions.
auto witnessFnTy = witnessRef->getType();
// Compute the substitutions.
ArrayRef<Substitution> substitutions =
swiftValueType->gatherAllSubstitutions(
gen.SGM.SwiftModule, nullptr);
if (!substitutions.empty()) {
// Substitute into the witness function type.
witnessFnTy = witnessFnTy.substGenericArgs(gen.SGM.M, substitutions);
}
// Call the witness.
SILType resultTy = gen.getLoweredType(objcType);
SILValue bridgedValue = gen.B.createApply(loc, witnessRef, witnessFnTy,
resultTy, substitutions,
swiftValue.borrow()
.getUnmanagedValue());
return gen.emitManagedRValueWithCleanup(bridgedValue);
}
/// Bridge the given Objective-C object to its corresponding Swift
/// value, using the appropriate witness for the
/// _ObjectiveCBridgeable._unconditionallyBridgeFromObjectiveC requirement.
static Optional<ManagedValue>
emitBridgeObjectiveCToNative(SILGenFunction &gen,
SILLocation loc,
ManagedValue objcValue,
ProtocolConformance *conformance) {
// Find the _unconditionallyBridgeFromObjectiveC requirement.
auto requirement =
gen.SGM.getUnconditionallyBridgeFromObjectiveCRequirement(loc);
if (!requirement) return None;
// Retrieve the _unconditionallyBridgeFromObjectiveC witness.
auto witness = conformance->getWitness(requirement, nullptr);
assert(witness);
// Create a reference to the witness.
SILDeclRef witnessConstant(witness.getDecl());
auto witnessRef = gen.emitGlobalFunctionRef(loc, witnessConstant);
// Determine the substitutions.
auto witnessFnTy = witnessRef->getType().castTo<SILFunctionType>();
Type swiftValueType = conformance->getType();
ArrayRef<Substitution> substitutions =
swiftValueType->gatherAllSubstitutions(
gen.SGM.SwiftModule, nullptr);
// Substitute into the witness function type.
if (!substitutions.empty())
witnessFnTy = witnessFnTy->substGenericArgs(gen.SGM.M, gen.SGM.SwiftModule,
substitutions);
// If the Objective-C value isn't optional, wrap it in an optional.
Type objcValueType = objcValue.getType().getSwiftRValueType();
if (!objcValueType->getOptionalObjectType()) {
SILType loweredOptTy =
gen.SGM.getLoweredType(OptionalType::get(objcValueType));
auto *someDecl = gen.getASTContext().getOptionalSomeDecl();
auto *enumInst = gen.B.createEnum(loc, objcValue.getValue(), someDecl,
loweredOptTy);
objcValue = ManagedValue(enumInst, objcValue.getCleanup());
}
// Call the witness.
Type metatype = MetatypeType::get(swiftValueType);
SILValue metatypeValue = gen.B.createMetatype(loc,
gen.getLoweredType(metatype));
auto witnessCI = gen.getConstantInfo(witnessConstant);
CanType formalResultTy = witnessCI.LoweredInterfaceType.getResult();
// Set up the generic signature.
CanGenericSignature witnessGenericSignature;
if (auto genericSig =
cast<AbstractFunctionDecl>(witness.getDecl())->getGenericSignature())
witnessGenericSignature = genericSig->getCanonicalSignature();
GenericContextScope genericContextScope(gen.SGM.Types,
witnessGenericSignature);
return gen.emitApply(loc, ManagedValue::forUnmanaged(witnessRef),
substitutions,
{ objcValue, ManagedValue::forUnmanaged(metatypeValue) },
witnessFnTy,
AbstractionPattern(witnessGenericSignature,
formalResultTy),
swiftValueType->getCanonicalType(),
ApplyOptions::None, None, None,
SGFContext())
.getAsSingleValue(gen, loc);
}
static ManagedValue emitBridgeBoolToObjCBool(SILGenFunction &gen,
SILLocation loc,
ManagedValue swiftBool) {
// func _convertBoolToObjCBool(Bool) -> ObjCBool
SILValue boolToObjCBoolFn
= gen.emitGlobalFunctionRef(loc, gen.SGM.getBoolToObjCBoolFn());
SILType resultTy =gen.getLoweredLoadableType(gen.SGM.Types.getObjCBoolType());
SILValue result = gen.B.createApply(loc, boolToObjCBoolFn,
boolToObjCBoolFn->getType(),
resultTy, {}, swiftBool.forward(gen));
return gen.emitManagedRValueWithCleanup(result);
}
static ManagedValue emitBridgeBoolToDarwinBoolean(SILGenFunction &gen,
SILLocation loc,
ManagedValue swiftBool) {
// func _convertBoolToDarwinBoolean(Bool) -> DarwinBoolean
SILValue boolToDarwinBooleanFn
= gen.emitGlobalFunctionRef(loc, gen.SGM.getBoolToDarwinBooleanFn());
SILType resultTy =
gen.getLoweredLoadableType(gen.SGM.Types.getDarwinBooleanType());
SILValue result = gen.B.createApply(loc, boolToDarwinBooleanFn,
boolToDarwinBooleanFn->getType(),
resultTy, {}, swiftBool.forward(gen));
return gen.emitManagedRValueWithCleanup(result);
}
static ManagedValue emitBridgeForeignBoolToBool(SILGenFunction &gen,
SILLocation loc,
ManagedValue foreignBool,
SILDeclRef bridgingFnRef) {
// func _convertObjCBoolToBool(ObjCBool) -> Bool
SILValue bridgingFn = gen.emitGlobalFunctionRef(loc, bridgingFnRef);
SILType resultTy = gen.getLoweredLoadableType(gen.SGM.Types.getBoolType());
SILValue result = gen.B.createApply(loc, bridgingFn, bridgingFn->getType(),
resultTy, {}, foreignBool.forward(gen));
return gen.emitManagedRValueWithCleanup(result);
}
static void buildFuncToBlockInvokeBody(SILGenFunction &gen,
SILLocation loc,
CanSILFunctionType blockTy,
CanSILBlockStorageType blockStorageTy,
CanSILFunctionType funcTy) {
Scope scope(gen.Cleanups, CleanupLocation::get(loc));
SILBasicBlock *entry = &*gen.F.begin();
// Get the captured native function value out of the block.
auto storageAddrTy = SILType::getPrimitiveAddressType(blockStorageTy);
auto storage = new (gen.SGM.M) SILArgument(entry, storageAddrTy);
auto capture = gen.B.createProjectBlockStorage(loc, storage);
auto &funcTL = gen.getTypeLowering(funcTy);
auto fn = gen.emitLoad(loc, capture, funcTL, SGFContext(), IsNotTake);
// Collect the block arguments, which may have nonstandard conventions.
assert(blockTy->getParameters().size()
== funcTy->getParameters().size()
&& "block and function types don't match");
SmallVector<ManagedValue, 4> args;
for (unsigned i : indices(funcTy->getParameters())) {
auto &funcParam = funcTy->getParameters()[i];
auto &param = blockTy->getParameters()[i];
SILValue v = new (gen.SGM.M) SILArgument(entry, param.getSILType());
ManagedValue mv;
// If the parameter is a block, we need to copy it to ensure it lives on
// the heap. The adapted closure value might outlive the block's original
// scope.
if (param.getSILType().isBlockPointerCompatible()) {
// We still need to consume the original block if it was owned.
switch (param.getConvention()) {
case ParameterConvention::Direct_Owned:
gen.emitManagedRValueWithCleanup(v);
break;
case ParameterConvention::Direct_Deallocating:
case ParameterConvention::Direct_Guaranteed:
case ParameterConvention::Direct_Unowned:
break;
case ParameterConvention::Indirect_In:
case ParameterConvention::Indirect_In_Guaranteed:
case ParameterConvention::Indirect_Inout:
case ParameterConvention::Indirect_InoutAliasable:
llvm_unreachable("indirect params to blocks not supported");
}
SILValue blockCopy = gen.B.createCopyBlock(loc, v);
mv = gen.emitManagedRValueWithCleanup(blockCopy);
} else {
switch (param.getConvention()) {
case ParameterConvention::Direct_Owned:
// Consume owned parameters at +1.
mv = gen.emitManagedRValueWithCleanup(v);
break;
case ParameterConvention::Direct_Guaranteed:
case ParameterConvention::Direct_Unowned:
// We need to independently retain the value.
mv = gen.emitManagedRetain(loc, v);
break;
case ParameterConvention::Direct_Deallocating:
// We do not need to retain the value since the value is already being
// deallocated.
mv = ManagedValue::forUnmanaged(v);
break;
case ParameterConvention::Indirect_In_Guaranteed:
case ParameterConvention::Indirect_In:
case ParameterConvention::Indirect_Inout:
case ParameterConvention::Indirect_InoutAliasable:
llvm_unreachable("indirect arguments to blocks not supported");
}
}
args.push_back(gen.emitBridgedToNativeValue(loc, mv,
SILFunctionTypeRepresentation::CFunctionPointer,
funcParam.getType()));
}
CanType resultType;
SILValue indirectResult;
if (funcTy->getNumAllResults() == 0)
resultType = TupleType::getEmpty(gen.SGM.getASTContext());
else {
auto result = funcTy->getSingleResult();
resultType = result.getType();
auto &tl = gen.getTypeLowering(result.getSILType());
if (tl.isAddressOnly()) {
assert(result.getConvention() == ResultConvention::Indirect);
}
}
// Call the native function.
ManagedValue result = gen.emitMonomorphicApply(loc, fn, args,
resultType,
ApplyOptions::None,
None, None)
.getAsSingleValue(gen, loc);
// Bridge the result back to ObjC.
result = gen.emitNativeToBridgedValue(loc, result,
SILFunctionTypeRepresentation::CFunctionPointer,
blockTy->getSILResult().getSwiftRValueType());
auto resultVal = result.forward(gen);
scope.pop();
gen.B.createReturn(loc, resultVal);
}
/// Bridge a native function to a block with a thunk.
ManagedValue SILGenFunction::emitFuncToBlock(SILLocation loc,
ManagedValue fn,
CanSILFunctionType blockTy) {
// Build the invoke function signature. The block will capture the original
// function value.
auto fnTy = fn.getType().castTo<SILFunctionType>();
auto fnInterfaceTy = cast<SILFunctionType>(CanType(
ArchetypeBuilder::mapTypeOutOfContext(SGM.M.getSwiftModule(),
F.getContextGenericParams(),
fnTy)));
auto blockInterfaceTy = cast<SILFunctionType>(CanType(
ArchetypeBuilder::mapTypeOutOfContext(SGM.M.getSwiftModule(),
F.getContextGenericParams(),
blockTy)));
auto storageTy = SILBlockStorageType::get(fnTy);
auto storageInterfaceTy = SILBlockStorageType::get(fnInterfaceTy);
// Build the invoke function type.
SmallVector<SILParameterInfo, 4> params;
params.push_back(SILParameterInfo(storageInterfaceTy,
ParameterConvention::Indirect_InoutAliasable));
std::copy(blockInterfaceTy->getParameters().begin(),
blockInterfaceTy->getParameters().end(),
std::back_inserter(params));
// The block invoke function must be pseudogeneric. This should be OK for now
// since a bridgeable function's parameters and returns should all be
// trivially representable in ObjC so not need to exercise the type metadata.
//
// Ultimately we may need to capture generic parameters in block storage, but
// that will require a redesign of the interface to support dependent-layout
// context. Currently we don't capture anything directly into a block but a
// Swift closure, but that's totally dumb.
auto invokeTy =
SILFunctionType::get(F.getLoweredFunctionType()->getGenericSignature(),
SILFunctionType::ExtInfo()
.withRepresentation(SILFunctionType::Representation::
CFunctionPointer)
.withIsPseudogeneric(),
ParameterConvention::Direct_Unowned,
params,
blockInterfaceTy->getAllResults(),
blockInterfaceTy->getOptionalErrorResult(),
getASTContext());
// Create the invoke function. Borrow the mangling scheme from reabstraction
// thunks, which is what we are in spirit.
auto thunk = SGM.getOrCreateReabstractionThunk(F.getContextGenericParams(),
invokeTy,
fnTy,
blockTy,
F.isFragile());
// Build it if necessary.
if (thunk->empty()) {
thunk->setContextGenericParams(F.getContextGenericParams());
SILGenFunction thunkSGF(SGM, *thunk);
auto loc = RegularLocation::getAutoGeneratedLocation();
buildFuncToBlockInvokeBody(thunkSGF, loc, blockTy, storageTy, fnTy);
}
// Form the block on the stack.
auto storageAddrTy = SILType::getPrimitiveAddressType(storageTy);
auto storage = emitTemporaryAllocation(loc, storageAddrTy);
auto capture = B.createProjectBlockStorage(loc, storage);
// Store the function to the block without claiming it, so that it still
// gets cleaned up in scope. Copying the block will create an independent
// reference.
B.createStore(loc, fn.getValue(), capture);
auto invokeFn = B.createFunctionRef(loc, thunk);
auto stackBlock = B.createInitBlockStorageHeader(loc, storage, invokeFn,
SILType::getPrimitiveObjectType(blockTy),
getForwardingSubstitutions());
// Copy the block so we have an independent heap object we can hand off.
auto heapBlock = B.createCopyBlock(loc, stackBlock);
return emitManagedRValueWithCleanup(heapBlock);
}
static ManagedValue emitNativeToCBridgedNonoptionalValue(SILGenFunction &gen,
SILLocation loc,
ManagedValue v,
SILType bridgedTy) {
CanType loweredBridgedTy = bridgedTy.getSwiftRValueType();
CanType loweredNativeTy = v.getType().getSwiftRValueType();
if (loweredNativeTy == loweredBridgedTy)
return v;
// If the input is a native type with a bridged mapping, convert it.
#define BRIDGE_TYPE(BridgedModule,BridgedType, NativeModule,NativeType,Opt) \
if (loweredNativeTy == gen.SGM.Types.get##NativeType##Type() \
&& loweredBridgedTy == gen.SGM.Types.get##BridgedType##Type()) { \
return emitBridge##NativeType##To##BridgedType(gen, loc, v); \
}
#include "swift/SIL/BridgedTypes.def"
// Bridge thick to Objective-C metatypes.
if (auto bridgedMetaTy = dyn_cast<AnyMetatypeType>(loweredBridgedTy)) {
if (bridgedMetaTy->getRepresentation() == MetatypeRepresentation::ObjC) {
SILValue native = gen.B.emitThickToObjCMetatype(loc, v.getValue(),
SILType::getPrimitiveObjectType(loweredBridgedTy));
return ManagedValue(native, v.getCleanup());
}
}
// Bridge native functions to blocks.
auto bridgedFTy = dyn_cast<SILFunctionType>(loweredBridgedTy);
if (bridgedFTy
&& bridgedFTy->getRepresentation() == SILFunctionType::Representation::Block){
auto nativeFTy = cast<SILFunctionType>(loweredNativeTy);
if (nativeFTy->getRepresentation() != SILFunctionType::Representation::Block)
return gen.emitFuncToBlock(loc, v, bridgedFTy);
}
// If the native type conforms to _ObjectiveCBridgeable, use its
// _bridgeToObjectiveC witness.
if (auto conformance =
gen.SGM.getConformanceToObjectiveCBridgeable(loc, loweredNativeTy)) {
if (auto result = emitBridgeNativeToObjectiveC(gen, loc, v, conformance))
return *result;
assert(gen.SGM.getASTContext().Diags.hadAnyError() &&
"Bridging code should have complained");
return gen.emitUndef(loc, bridgedTy);
}
// Bridge Error to NSError.
if (loweredBridgedTy == gen.SGM.Types.getNSErrorType()) {
return gen.emitNativeToBridgedError(loc, v, loweredBridgedTy);
}
// Fall back to dynamic Any-to-id bridging.
// The destination type should be AnyObject in this case.
assert(loweredBridgedTy->isEqual(
gen.getASTContext().getProtocol(KnownProtocolKind::AnyObject)
->getDeclaredType()));
// If the input argument is known to be an existential, save the runtime
// some work by opening it.
if (loweredNativeTy->isExistentialType()) {
auto openedTy = ArchetypeType::getOpened(loweredNativeTy);
auto openedExistential = gen.emitOpenExistential(loc, v, openedTy,
gen.getLoweredType(openedTy));
v = gen.manageOpaqueValue(openedExistential, loc, SGFContext());
loweredNativeTy = openedTy;
}
// Call into the stdlib intrinsic.
if (auto bridgeAnything =
gen.getASTContext().getBridgeAnythingToObjectiveC(nullptr)) {
Substitution sub(loweredNativeTy, {});
// Put the value into memory if necessary.
assert(v.getType().isTrivial(gen.SGM.M) || v.hasCleanup());
if (v.getType().isObject()) {
auto tmp = gen.emitTemporaryAllocation(loc, v.getType());
v.forwardInto(gen, loc, tmp);
v = gen.emitManagedBufferWithCleanup(tmp);
}
return gen.emitApplyOfLibraryIntrinsic(loc, bridgeAnything, sub, v,
SGFContext())
.getAsSingleValue(gen, loc);
}
// Shouldn't get here unless the standard library is busted.
return gen.emitUndef(loc, bridgedTy);
}
static ManagedValue emitNativeToCBridgedValue(SILGenFunction &gen,
SILLocation loc,
ManagedValue v,
SILType bridgedTy) {
CanType loweredBridgedTy = bridgedTy.getSwiftRValueType();
CanType loweredNativeTy = v.getType().getSwiftRValueType();
if (loweredNativeTy == loweredBridgedTy)
return v;
if (loweredBridgedTy.getAnyOptionalObjectType()
&& loweredNativeTy.getAnyOptionalObjectType()) {
return gen.emitOptionalToOptional(loc, v, bridgedTy,
emitNativeToCBridgedValue);
}
// Check if we need to wrap the bridged result in an optional.
OptionalTypeKind OTK;
if (SILType bridgedObjectType =
bridgedTy.getAnyOptionalObjectType(gen.SGM.M, OTK)) {
auto bridgedPayload
= emitNativeToCBridgedNonoptionalValue(gen, loc, v, bridgedObjectType);
return gen.getOptionalSomeValue(loc, bridgedPayload,
gen.getTypeLowering(bridgedTy));
}
return emitNativeToCBridgedNonoptionalValue(gen, loc, v, bridgedTy);
}
ManagedValue SILGenFunction::emitNativeToBridgedValue(SILLocation loc,
ManagedValue v,
SILFunctionTypeRepresentation destRep,
CanType loweredBridgedTy){
switch (getSILFunctionLanguage(destRep)) {
case SILFunctionLanguage::Swift:
// No additional bridging needed for native functions.
return v;
case SILFunctionLanguage::C:
return emitNativeToCBridgedValue(*this, loc, v,
SILType::getPrimitiveObjectType(loweredBridgedTy));
}
llvm_unreachable("bad CC");
}
static void buildBlockToFuncThunkBody(SILGenFunction &gen,
SILLocation loc,
CanSILFunctionType blockTy,
CanSILFunctionType funcTy) {
// Collect the native arguments, which should all be +1.
Scope scope(gen.Cleanups, CleanupLocation::get(loc));
assert(blockTy->getParameters().size()
== funcTy->getParameters().size()
&& "block and function types don't match");
SmallVector<ManagedValue, 4> args;
SILBasicBlock *entry = &*gen.F.begin();
CanType resultType;
SILValue indirectResult;
if (funcTy->getNumAllResults() == 0)
resultType = TupleType::getEmpty(gen.SGM.getASTContext());
else {
auto result = funcTy->getSingleResult();
resultType = result.getType();
auto &tl = gen.getTypeLowering(result.getSILType());
if (tl.isAddressOnly()) {
assert(result.getConvention() == ResultConvention::Indirect);
indirectResult = new (gen.SGM.M) SILArgument(entry, result.getSILType());
}
}
for (unsigned i : indices(funcTy->getParameters())) {
auto &param = funcTy->getParameters()[i];
auto &blockParam = blockTy->getParameters()[i];
auto &tl = gen.getTypeLowering(param.getSILType());
SILValue v = new (gen.SGM.M) SILArgument(entry, param.getSILType());
auto mv = gen.emitManagedRValueWithCleanup(v, tl);
args.push_back(gen.emitNativeToBridgedValue(loc, mv,
SILFunctionTypeRepresentation::Block,
blockParam.getType()));
}
// Add the block argument.
SILValue blockV
= new (gen.SGM.M) SILArgument(entry,
SILType::getPrimitiveObjectType(blockTy));
ManagedValue block = gen.emitManagedRValueWithCleanup(blockV);
// Call the block.
// TODO: Emit directly into the indirect result.
ManagedValue result = gen.emitMonomorphicApply(loc, block, args,
resultType,
ApplyOptions::None,
/*override CC*/ SILFunctionTypeRepresentation::Block,
/*foreign error*/ None)
.getAsSingleValue(gen, loc);
// Return the result at +1.
auto r = result.forward(gen);
if (indirectResult) {
gen.B.createCopyAddr(loc, r, indirectResult,
IsTake, IsInitialization);
r = gen.B.createTuple(loc, funcTy->getSILResult(), {});
}
scope.pop();
gen.B.createReturn(loc, r);
}
/// Bridge a native function to a block with a thunk.
ManagedValue
SILGenFunction::emitBlockToFunc(SILLocation loc,
ManagedValue block,
CanSILFunctionType funcTy) {
CanSILFunctionType substFnTy;
SmallVector<Substitution, 4> subs;
// Declare the thunk.
auto blockTy = block.getType().castTo<SILFunctionType>();
auto thunkTy = buildThunkType(block, funcTy, substFnTy, subs);
auto thunk = SGM.getOrCreateReabstractionThunk(F.getContextGenericParams(),
thunkTy,
blockTy,
funcTy,
F.isFragile());
// Build it if necessary.
if (thunk->empty()) {
SILGenFunction thunkSGF(SGM, *thunk);
thunk->setContextGenericParams(F.getContextGenericParams());
auto loc = RegularLocation::getAutoGeneratedLocation();
buildBlockToFuncThunkBody(thunkSGF, loc, blockTy, funcTy);
}
// Create it in the current function.
auto thunkValue = B.createFunctionRef(loc, thunk);
auto thunkedFn = B.createPartialApply(loc, thunkValue,
SILType::getPrimitiveObjectType(substFnTy),
subs, block.forward(*this),
SILType::getPrimitiveObjectType(funcTy));
return emitManagedRValueWithCleanup(thunkedFn);
}
static ManagedValue emitCBridgedToNativeValue(SILGenFunction &gen,
SILLocation loc,
ManagedValue v,
SILType nativeTy) {
CanType loweredNativeTy = nativeTy.getSwiftRValueType();
CanType loweredBridgedTy = v.getType().getSwiftRValueType();
if (loweredNativeTy == loweredBridgedTy)
return v;
if (loweredNativeTy.getAnyOptionalObjectType()) {
return gen.emitOptionalToOptional(loc, v, nativeTy,
emitCBridgedToNativeValue);
}
// Bridge Bool to ObjCBool or DarwinBoolean when requested.
if (loweredNativeTy == gen.SGM.Types.getBoolType()) {
if (loweredBridgedTy == gen.SGM.Types.getObjCBoolType()) {
return emitBridgeForeignBoolToBool(gen, loc, v,
gen.SGM.getObjCBoolToBoolFn());
}
if (loweredBridgedTy == gen.SGM.Types.getDarwinBooleanType()) {
return emitBridgeForeignBoolToBool(gen, loc, v,
gen.SGM.getDarwinBooleanToBoolFn());
}
}
// Bridge Objective-C to thick metatypes.
if (auto bridgedMetaTy = dyn_cast<AnyMetatypeType>(loweredBridgedTy)){
if (bridgedMetaTy->getRepresentation() == MetatypeRepresentation::ObjC) {
SILValue native = gen.B.emitObjCToThickMetatype(loc, v.getValue(),
gen.getLoweredType(loweredNativeTy));
return ManagedValue(native, v.getCleanup());
}
}
// Bridge blocks back into native function types.
auto bridgedFTy = dyn_cast<SILFunctionType>(loweredBridgedTy);
if (bridgedFTy
&& bridgedFTy->getRepresentation() == SILFunctionType::Representation::Block){
auto nativeFTy = cast<SILFunctionType>(loweredNativeTy);
if (nativeFTy->getRepresentation() != SILFunctionType::Representation::Block)
return gen.emitBlockToFunc(loc, v, nativeFTy);
}
// Bridge via _ObjectiveCBridgeable.
if (auto conformance =
gen.SGM.getConformanceToObjectiveCBridgeable(loc, loweredNativeTy)) {
if (auto result = emitBridgeObjectiveCToNative(gen, loc, v, conformance))
return *result;
assert(gen.SGM.getASTContext().Diags.hadAnyError() &&
"Bridging code should have complained");
return gen.emitUndef(loc, nativeTy);
}
// Bridge NSError to Error.
if (loweredBridgedTy == gen.SGM.Types.getNSErrorType())
return gen.emitBridgedToNativeError(loc, v);
// id-to-Any bridging.
if (loweredNativeTy->isAny()) {
assert(loweredBridgedTy->isEqual(
gen.getASTContext().getProtocol(KnownProtocolKind::AnyObject)
->getDeclaredType())
&& "Any should bridge to AnyObject");
// TODO: Ever need to handle +0 values here?
assert(v.hasCleanup());
// Use a runtime call to bridge the AnyObject to Any. We do this instead of
// a simple AnyObject-to-Any upcast because the ObjC API may have returned
// a null object in spite of its annotation.
// Bitcast to Optional. This provides a barrier to the optimizer to prevent
// it from attempting to eliminate null checks.
auto optionalBridgedTy = OptionalType::get(loweredBridgedTy)
->getCanonicalType();
auto optionalV = gen.B.createUncheckedBitCast(loc, v.getValue(),
SILType::getPrimitiveObjectType(optionalBridgedTy));
auto optionalMV = ManagedValue(optionalV, v.getCleanup());
return gen.emitApplyOfLibraryIntrinsic(loc,
gen.getASTContext().getBridgeAnyObjectToAny(nullptr),
{}, optionalMV, SGFContext())
.getAsSingleValue(gen, loc);
}
return v;
}
ManagedValue SILGenFunction::emitBridgedToNativeValue(SILLocation loc,
ManagedValue v,
SILFunctionTypeRepresentation srcRep,
CanType nativeTy) {
switch (getSILFunctionLanguage(srcRep)) {
case SILFunctionLanguage::Swift:
// No additional bridging needed for native functions.
return v;
case SILFunctionLanguage::C:
return emitCBridgedToNativeValue(*this, loc, v, getLoweredType(nativeTy));
}
llvm_unreachable("bad CC");
}
/// Bridge a possibly-optional foreign error type to Error.
ManagedValue SILGenFunction::emitBridgedToNativeError(SILLocation loc,
ManagedValue bridgedError) {
// If the incoming error is non-optional, just do an existential erasure.
CanType bridgedErrorTy = bridgedError.getType().getSwiftRValueType();
if (!bridgedErrorTy.getAnyOptionalObjectType()) {
auto nativeErrorTy = SILType::getExceptionType(getASTContext());
auto conformance = SGM.getNSErrorConformanceToError();
if (!conformance) return emitUndef(loc, nativeErrorTy);
ProtocolConformanceRef conformanceArray[] = {
ProtocolConformanceRef(conformance)
};
auto conformances = getASTContext().AllocateCopy(conformanceArray);
SILValue nativeError =
B.createInitExistentialRef(loc, nativeErrorTy, bridgedErrorTy,
bridgedError.forward(*this), conformances);
return emitManagedRValueWithCleanup(nativeError);
}
// Otherwise, we need to call a runtime function to potential substitute
// a standard error for a nil NSError.
auto bridgeFn = emitGlobalFunctionRef(loc, SGM.getNSErrorToErrorFn());
auto bridgeFnType = bridgeFn->getType().castTo<SILFunctionType>();
assert(bridgeFnType->getNumAllResults() == 1);
assert(bridgeFnType->getAllResults()[0].getConvention()
== ResultConvention::Owned);
auto nativeErrorType = bridgeFnType->getAllResults()[0].getSILType();
assert(bridgeFnType->getParameters()[0].getConvention()
== ParameterConvention::Direct_Owned);
SILValue nativeError = B.createApply(loc, bridgeFn, bridgeFn->getType(),
nativeErrorType, {},
bridgedError.forward(*this));
return emitManagedRValueWithCleanup(nativeError);
}
/// Bridge Error to a foreign error type.
ManagedValue SILGenFunction::emitNativeToBridgedError(SILLocation loc,
ManagedValue nativeError,
CanType bridgedErrorProto) {
assert(bridgedErrorProto == SGM.Types.getNSErrorType() &&
"only handling NSError for now");
auto bridgeFn = emitGlobalFunctionRef(loc, SGM.getErrorToNSErrorFn());
auto bridgeFnType = bridgeFn->getType().castTo<SILFunctionType>();
assert(bridgeFnType->getNumAllResults() == 1);
assert(bridgeFnType->getAllResults()[0].getConvention()
== ResultConvention::Owned);
auto bridgeErrorType = bridgeFnType->getAllResults()[0].getSILType();
assert(bridgeFnType->getParameters()[0].getConvention()
== ParameterConvention::Direct_Owned);
SILValue bridgedError = B.createApply(loc, bridgeFn, bridgeFn->getType(),
bridgeErrorType, {},
nativeError.forward(*this));
return emitManagedRValueWithCleanup(bridgedError);
}
//===----------------------------------------------------------------------===//
// ObjC method thunks
//===----------------------------------------------------------------------===//
static SILValue emitBridgeReturnValue(SILGenFunction &gen,
SILLocation loc,
SILValue result,
SILFunctionTypeRepresentation fnTypeRepr,
CanType bridgedTy) {
Scope scope(gen.Cleanups, CleanupLocation::get(loc));
ManagedValue native = gen.emitManagedRValueWithCleanup(result);
ManagedValue bridged = gen.emitNativeToBridgedValue(loc, native, fnTypeRepr,
bridgedTy);
return bridged.forward(gen);
}
/// Take an argument at +0 and bring it to +1.
static SILValue emitObjCUnconsumedArgument(SILGenFunction &gen,
SILLocation loc,
SILValue arg) {
auto &lowering = gen.getTypeLowering(arg->getType());
// If address-only, make a +1 copy and operate on that.
if (lowering.isAddressOnly()) {
auto tmp = gen.emitTemporaryAllocation(loc, arg->getType().getObjectType());
gen.B.createCopyAddr(loc, arg, tmp, IsNotTake, IsInitialization);
return tmp;
}
lowering.emitRetainValue(gen.B, loc, arg);
return arg;
}
/// Bridge argument types and adjust retain count conventions for an ObjC thunk.
static SILFunctionType *emitObjCThunkArguments(SILGenFunction &gen,
SILLocation loc,
SILDeclRef thunk,
SmallVectorImpl<SILValue> &args,
SILValue &foreignErrorSlot,
Optional<ForeignErrorConvention> &foreignError) {
SILDeclRef native = thunk.asForeign(false);
auto mod = gen.SGM.M.getSwiftModule();
auto subs = gen.F.getForwardingSubstitutions();
auto objcInfo = gen.SGM.Types.getConstantInfo(thunk);
auto objcFnTy = objcInfo.SILFnType->substGenericArgs(gen.SGM.M, mod, subs);
auto swiftInfo = gen.SGM.Types.getConstantInfo(native);
auto swiftFnTy = swiftInfo.SILFnType->substGenericArgs(gen.SGM.M, mod, subs);
// We must have the same context archetypes as the unthunked function.
assert(objcInfo.ContextGenericParams == swiftInfo.ContextGenericParams);
SmallVector<ManagedValue, 8> bridgedArgs;
bridgedArgs.reserve(objcFnTy->getParameters().size());
SILFunction *orig = gen.SGM.getFunction(native, NotForDefinition);
// Find the foreign error convention if we have one.
if (orig->getLoweredFunctionType()->hasErrorResult()) {
auto func = cast<AbstractFunctionDecl>(thunk.getDecl());
foreignError = func->getForeignErrorConvention();
assert(foreignError && "couldn't find foreign error convention!");
}
// We don't know what to do with indirect results from the Objective-C side.
assert(objcFnTy->getNumIndirectResults() == 0 &&
"Objective-C methods cannot have indirect results");
// Emit the other arguments, taking ownership of arguments if necessary.
auto inputs = objcFnTy->getParameters();
auto nativeInputs = swiftFnTy->getParameters();
assert(inputs.size() ==
nativeInputs.size() + unsigned(foreignError.hasValue()));
for (unsigned i = 0, e = inputs.size(); i < e; ++i) {
SILType argTy = inputs[i].getSILType();
SILValue arg = new(gen.F.getModule()) SILArgument(gen.F.begin(), argTy);
// If this parameter is the foreign error slot, pull it out.
// It does not correspond to a native argument.
if (foreignError && i == foreignError->getErrorParameterIndex()) {
foreignErrorSlot = arg;
continue;
}
// If this parameter is deallocating, emit an unmanaged rvalue and
// continue. The object has the deallocating bit set so retain, release is
// irrelevant.
if (inputs[i].isDeallocating()) {
bridgedArgs.push_back(ManagedValue::forUnmanaged(arg));
continue;
}
// If the argument is a block, copy it.
if (argTy.isBlockPointerCompatible()) {
auto copy = gen.B.createCopyBlock(loc, arg);
// If the argument is consumed, we're still responsible for releasing the
// original.
if (inputs[i].isConsumed())
gen.emitManagedRValueWithCleanup(arg);
arg = copy;
}
// Convert the argument to +1 if necessary.
else if (!inputs[i].isConsumed()) {
arg = emitObjCUnconsumedArgument(gen, loc, arg);
}
auto managedArg = gen.emitManagedRValueWithCleanup(arg);
bridgedArgs.push_back(managedArg);
}
assert(bridgedArgs.size() + unsigned(foreignError.hasValue())
== objcFnTy->getParameters().size() &&
"objc inputs don't match number of arguments?!");
assert(bridgedArgs.size() == swiftFnTy->getParameters().size() &&
"swift inputs don't match number of arguments?!");
assert((foreignErrorSlot || !foreignError) &&
"didn't find foreign error slot");
// Bridge the input types.
// FIXME: We really want alloc_stacks to outlive this scope, because
// bridging id-to-Any requires allocating an Any which gets passed to
// the native entry point.
// Scope scope(gen.Cleanups, CleanupLocation::get(loc));
assert(bridgedArgs.size() == nativeInputs.size());
for (unsigned i = 0, size = bridgedArgs.size(); i < size; ++i) {
SILType argTy = swiftFnTy->getParameters()[i].getSILType();
ManagedValue native =
gen.emitBridgedToNativeValue(loc,
bridgedArgs[i],
SILFunctionTypeRepresentation::ObjCMethod,
argTy.getSwiftType());
SILValue argValue;
if (nativeInputs[i].isConsumed())
argValue = native.forward(gen);
else
argValue = native.getValue();
args.push_back(argValue);
}
return objcFnTy;
}
void SILGenFunction::emitNativeToForeignThunk(SILDeclRef thunk) {
assert(thunk.isForeign);
SILDeclRef native = thunk.asForeign(false);
auto nativeInfo = getConstantInfo(native);
auto subs = F.getForwardingSubstitutions();
auto substTy = nativeInfo.SILFnType->substGenericArgs(
SGM.M, SGM.M.getSwiftModule(), subs);
SILType substSILTy = SILType::getPrimitiveObjectType(substTy);
// Use the same context generic params as the native entry point.
F.setContextGenericParams(nativeInfo.ContextGenericParams);
auto loc = thunk.getAsRegularLocation();
loc.markAutoGenerated();
Scope scope(Cleanups, CleanupLocation::get(loc));
// If we are bridging a Swift method with an Any return value, create a
// stack allocation to hold the result, since Any is address-only.
SmallVector<SILValue, 4> args;
if (substTy->getNumIndirectResults() > 0) {
SILResultInfo indirectResult = substTy->getSingleResult();
args.push_back(emitTemporaryAllocation(loc, indirectResult.getSILType()));
}
// Now, enter a cleanup used for bridging the arguments. Note that if we
// have an indirect result, it must be outside of this scope, otherwise
// we will deallocate it too early.
Scope argScope(Cleanups, CleanupLocation::get(loc));
// Bridge the arguments.
Optional<ForeignErrorConvention> foreignError;
SILValue foreignErrorSlot;
auto objcFnTy = emitObjCThunkArguments(*this, loc, thunk, args,
foreignErrorSlot, foreignError);
auto swiftResultTy =
F.mapTypeIntoContext(nativeInfo.SILFnType->getSILResult());
auto objcResultTy = objcFnTy->getSILResult();
// Call the native entry point.
SILValue nativeFn = emitGlobalFunctionRef(loc, native, nativeInfo);
CanType bridgedResultType = objcResultTy.getSwiftRValueType();
SILValue result;
assert(foreignError.hasValue() == substTy->hasErrorResult());
if (!substTy->hasErrorResult()) {
// Create the apply.
result = B.createApply(loc, nativeFn, substSILTy,
swiftResultTy, subs, args);
if (substTy->hasIndirectResults()) {
assert(substTy->getNumAllResults() == 1);
result = args[0];
}
// Leave the argument cleanup scope immediately. This isn't really
// necessary; it just limits lifetimes a little bit more.
argScope.pop();
// Now bridge the return value.
result = emitBridgeReturnValue(*this, loc, result,
objcFnTy->getRepresentation(),
bridgedResultType);
} else {
SILBasicBlock *contBB = createBasicBlock();
SILBasicBlock *errorBB = createBasicBlock();
SILBasicBlock *normalBB = createBasicBlock();
B.createTryApply(loc, nativeFn, substSILTy, subs, args,
normalBB, errorBB);
// Emit the non-error destination.
{
B.emitBlock(normalBB);
SILValue nativeResult = normalBB->createBBArg(swiftResultTy);
if (substTy->hasIndirectResults()) {
assert(substTy->getNumAllResults() == 1);
nativeResult = args[0];
}
// In this branch, the eventual return value is mostly created
// by bridging the native return value, but we may need to
// adjust it slightly.
SILValue bridgedResult =
emitBridgeReturnValueForForeignError(loc, nativeResult,
objcFnTy->getRepresentation(),
objcResultTy,
foreignErrorSlot, *foreignError);
B.createBranch(loc, contBB, bridgedResult);
}
// Emit the error destination.
{
B.emitBlock(errorBB);
SILValue nativeError =
errorBB->createBBArg(substTy->getErrorResult().getSILType());
// In this branch, the eventual return value is mostly invented.
// Store the native error in the appropriate location and return.
SILValue bridgedResult =
emitBridgeErrorForForeignError(loc, nativeError, objcResultTy,
foreignErrorSlot, *foreignError);
B.createBranch(loc, contBB, bridgedResult);
}
// Emit the join block.
B.emitBlock(contBB);
result = contBB->createBBArg(objcResultTy);
// Leave the scope now.
argScope.pop();
}
scope.pop();
B.createReturn(loc, result);
}
static SILValue
getThunkedForeignFunctionRef(SILGenFunction &gen,
SILLocation loc,
SILDeclRef foreign,
ArrayRef<ManagedValue> args,
ArrayRef<Substitution> subs,
const SILConstantInfo &foreignCI) {
assert(!foreign.isCurried
&& "should not thunk calling convention when curried");
// Produce a witness_method when thunking ObjC protocol methods.
auto dc = foreign.getDecl()->getDeclContext();
if (isa<ProtocolDecl>(dc) && cast<ProtocolDecl>(dc)->isObjC()) {
assert(subs.size() == 1);
auto thisType = subs[0].getReplacement()->getCanonicalType();
assert(isa<ArchetypeType>(thisType) && "no archetype for witness?!");
SILValue thisArg = args.back().getValue();
SILValue OpenedExistential;
if (!cast<ArchetypeType>(thisType)->getOpenedExistentialType().isNull())
OpenedExistential = thisArg;
auto conformance = ProtocolConformanceRef(cast<ProtocolDecl>(dc));
return gen.B.createWitnessMethod(loc, thisType, conformance, foreign,
foreignCI.getSILType(),
OpenedExistential);
// Produce a class_method when thunking imported ObjC methods.
} else if (foreignCI.SILFnType->getRepresentation()
== SILFunctionTypeRepresentation::ObjCMethod) {
// assert(subs.empty());
SILValue thisArg = args.back().getValue();
return gen.B.createClassMethod(loc, thisArg, foreign,
SILType::getPrimitiveObjectType(foreignCI.SILFnType),
/*volatile*/ true);
}
// Otherwise, emit a function_ref.
return gen.emitGlobalFunctionRef(loc, foreign);
}
/// Generate code to emit a thunk with native conventions that calls a
/// function with foreign conventions.
void SILGenFunction::emitForeignToNativeThunk(SILDeclRef thunk) {
assert(!thunk.isForeign && "foreign-to-native thunks only");
// Wrap the function in its original form.
auto fd = cast<AbstractFunctionDecl>(thunk.getDecl());
auto nativeCI = getConstantInfo(thunk);
auto nativeFormalResultTy = nativeCI.LoweredInterfaceType.getResult();
auto nativeFnTy = F.getLoweredFunctionType();
assert(nativeFnTy == nativeCI.SILFnType);
// Use the same context generic params as the native entry point.
F.setContextGenericParams(nativeCI.ContextGenericParams);
// Find the foreign error convention and 'self' parameter index.
Optional<ForeignErrorConvention> foreignError;
if (nativeFnTy->hasErrorResult()) {
foreignError = fd->getForeignErrorConvention();
assert(foreignError && "couldn't find foreign error convention!");
}
ImportAsMemberStatus memberStatus = fd->getImportAsMemberStatus();
// Forward the arguments.
auto forwardedParameters = fd->getParameterLists();
// For allocating constructors, 'self' is a metatype, not the 'self' value
// formally present in the constructor body.
Type allocatorSelfType;
if (thunk.kind == SILDeclRef::Kind::Allocator) {
allocatorSelfType = forwardedParameters[0]->getType(getASTContext())
->getLValueOrInOutObjectType();
forwardedParameters = forwardedParameters.slice(1);
}
SmallVector<SILValue, 8> params;
// Introduce indirect returns if necessary.
// TODO: Handle exploded results? We don't currently need to since the only
// bridged indirect type is Any.
SILValue indirectResult;
if (!nativeFnTy->getIndirectResults().empty()) {
assert(nativeFnTy->getIndirectResults().size() == 1
&& "bridged exploded result?!");
indirectResult = new (F.getModule()) SILArgument(F.begin(),
nativeFnTy->getIndirectResults()[0].getSILType());
}
for (auto *paramList : reversed(forwardedParameters))
bindParametersForForwarding(paramList, params);
if (allocatorSelfType) {
auto selfMetatype =
CanMetatypeType::get(allocatorSelfType->getCanonicalType());
auto selfArg = new (F.getModule()) SILArgument(
F.begin(),
getLoweredLoadableType(selfMetatype),
fd->getImplicitSelfDecl());
params.push_back(selfArg);
}
// Set up the throw destination if necessary.
CleanupLocation cleanupLoc(fd);
if (foreignError) {
prepareRethrowEpilog(cleanupLoc);
}
SILValue result;
{
Scope scope(Cleanups, fd);
SILDeclRef foreignDeclRef = thunk.asForeign(true);
SILConstantInfo foreignCI = getConstantInfo(foreignDeclRef);
auto foreignFnTy = foreignCI.SILFnType;
// Bridge all the arguments.
SmallVector<ManagedValue, 8> args;
unsigned foreignArgIndex = 0;
// A helper function to add a function error argument in the
// appropriate position.
auto maybeAddForeignErrorArg = [&] {
if (foreignError &&
foreignArgIndex == foreignError->getErrorParameterIndex()) {
args.push_back(ManagedValue());
foreignArgIndex++;
}
};
{
for (unsigned nativeParamIndex : indices(params)) {
// Bring the parameter to +1.
auto paramValue = params[nativeParamIndex];
auto thunkParam = nativeFnTy->getParameters()[nativeParamIndex];
// TODO: Could avoid a retain if the bridged parameter is also +0 and
// doesn't require a bridging conversion.
ManagedValue param;
switch (thunkParam.getConvention()) {
case ParameterConvention::Direct_Owned:
param = emitManagedRValueWithCleanup(paramValue);
break;
case ParameterConvention::Direct_Guaranteed:
case ParameterConvention::Direct_Unowned:
param = emitManagedRetain(fd, paramValue);
break;
case ParameterConvention::Direct_Deallocating:
param = ManagedValue::forUnmanaged(paramValue);
break;
case ParameterConvention::Indirect_Inout:
case ParameterConvention::Indirect_InoutAliasable:
param = ManagedValue::forLValue(paramValue);
break;
case ParameterConvention::Indirect_In:
param = emitManagedRValueWithCleanup(paramValue);
break;
case ParameterConvention::Indirect_In_Guaranteed:
auto tmp = emitTemporaryAllocation(fd, paramValue->getType());
B.createCopyAddr(fd, paramValue, tmp, IsNotTake, IsInitialization);
param = emitManagedRValueWithCleanup(tmp);
break;
}
maybeAddForeignErrorArg();
bool isSelf = nativeParamIndex == params.size() - 1;
if (memberStatus.isInstance()) {
// Leave space for `self` to be filled in later.
if (foreignArgIndex == memberStatus.getSelfIndex()) {
args.push_back({});
foreignArgIndex++;
}
// Use the `self` space we skipped earlier if it's time.
if (isSelf) {
foreignArgIndex = memberStatus.getSelfIndex();
}
} else if (memberStatus.isStatic() && isSelf) {
// Lose a static `self` parameter.
break;
}
auto foreignParam = foreignFnTy->getParameters()[foreignArgIndex++];
SILType foreignArgTy = F.mapTypeIntoContext(foreignParam.getSILType());
auto bridged = emitNativeToBridgedValue(fd, param,
SILFunctionTypeRepresentation::CFunctionPointer,
foreignArgTy.getSwiftRValueType());
// Handle C pointer arguments imported as indirect `self` arguments.
if (foreignParam.getConvention() == ParameterConvention::Indirect_In) {
auto temp = emitTemporaryAllocation(fd, bridged.getType());
bridged.forwardInto(*this, fd, temp);
bridged = emitManagedBufferWithCleanup(temp);
}
if (memberStatus.isInstance() && isSelf) {
// Fill in the `self` space.
args[memberStatus.getSelfIndex()] = bridged;
} else {
args.push_back(bridged);
}
}
}
maybeAddForeignErrorArg();
// Call the original.
auto subs = getForwardingSubstitutions();
auto fn = getThunkedForeignFunctionRef(*this, fd, foreignDeclRef, args, subs,
foreignCI);
auto fnType = fn->getType().castTo<SILFunctionType>();
fnType = fnType->substGenericArgs(SGM.M, SGM.SwiftModule, subs);
CanType substResultTy{
ArchetypeBuilder::mapTypeIntoContext(fd, nativeFormalResultTy)};
auto resultMV = emitApply(fd, ManagedValue::forUnmanaged(fn),
subs, args, fnType,
AbstractionPattern(nativeFnTy->getGenericSignature(),
nativeFormalResultTy),
substResultTy,
ApplyOptions::None, None, foreignError,
SGFContext())
.getAsSingleValue(*this, fd);
// TODO: Emit directly into the indirect result.
if (indirectResult) {
resultMV.forwardInto(*this, fd, indirectResult);
result = emitEmptyTuple(fd);
} else {
result = resultMV.forward(*this);
}
}
B.createReturn(ImplicitReturnLocation::getImplicitReturnLoc(fd), result);
// Emit the throw destination.
emitRethrowEpilog(fd);
}