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//===--- GenFunc.cpp - Swift IR Generation for Function Types -------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements IR generation for function types in Swift. This
// includes creating the IR type as well as capturing variables and
// performing calls.
//
// Swift supports three representations of functions:
//
// - thin, which are just a function pointer;
//
// - thick, which are a pair of a function pointer and
// an optional ref-counted opaque context pointer; and
//
// - block, which match the Apple blocks extension: a ref-counted
// pointer to a mostly-opaque structure with the function pointer
// stored at a fixed offset.
//
// The order of function parameters is as follows:
//
// - indirect return pointer
// - block context parameter, if applicable
// - expanded formal parameter types
// - implicit generic parameters
// - thick context parameter, if applicable
// - error result out-parameter, if applicable
// - witness_method generic parameters, if applicable
//
// The context and error parameters are last because they are
// optional: we'd like to be able to turn a thin function into a
// thick function, or a non-throwing function into a throwing one,
// without adding a thunk. A thick context parameter is required
// (but can be passed undef) if an error result is required.
//
// The additional generic parameters for witness methods follow the
// same logic: we'd like to be able to use non-generic method
// implementations directly as protocol witnesses if the rest of the
// ABI matches up.
//
// Note that some of this business with context parameters and error
// results is just IR formalism; on most of our targets, both of
// these are passed in registers. This is also why passing them
// as the final argument isn't bad for performance.
//
// For now, function pointer types are always stored as opaque
// pointers in LLVM IR; using a well-typed function type is
// very challenging because of issues with recursive type expansion,
// which can potentially introduce infinite types. For example:
// struct A {
// var fn: (A) -> ()
// }
// Our CC lowering expands the fields of A into the argument list
// of A.fn, which is necessarily infinite. Attempting to use better
// types when not in a situation like this would just make the
// compiler complacent, leading to a long tail of undiscovered
// crashes. So instead we always store as i8* and require the
// bitcast whenever we change representations.
//
//===----------------------------------------------------------------------===//
#include "swift/AST/ASTContext.h"
#include "swift/AST/ASTWalker.h"
#include "swift/AST/Builtins.h"
#include "swift/AST/Decl.h"
#include "swift/AST/IRGenOptions.h"
#include "swift/AST/Module.h"
#include "swift/AST/Pattern.h"
#include "swift/AST/PrettyStackTrace.h"
#include "swift/AST/SubstitutionMap.h"
#include "swift/AST/Types.h"
#include "swift/IRGen/Linking.h"
#include "clang/AST/ASTContext.h"
#include "clang/CodeGen/CodeGenABITypes.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Module.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/StringSwitch.h"
#include "BitPatternBuilder.h"
#include "Callee.h"
#include "ConstantBuilder.h"
#include "EnumPayload.h"
#include "Explosion.h"
#include "FixedTypeInfo.h"
#include "GenCall.h"
#include "GenClass.h"
#include "GenFunc.h"
#include "GenHeap.h"
#include "GenMeta.h"
#include "GenObjC.h"
#include "GenPointerAuth.h"
#include "GenPoly.h"
#include "GenProto.h"
#include "GenType.h"
#include "HeapTypeInfo.h"
#include "IRGenDebugInfo.h"
#include "IRGenFunction.h"
#include "IRGenModule.h"
#include "IndirectTypeInfo.h"
#include "ScalarPairTypeInfo.h"
#include "Signature.h"
#include "IRGenMangler.h"
using namespace swift;
using namespace irgen;
namespace {
/// Information about the IR-level signature of a function type.
class FuncSignatureInfo {
private:
/// The SIL function type being represented.
const CanSILFunctionType FormalType;
mutable Signature TheSignature;
public:
FuncSignatureInfo(CanSILFunctionType formalType)
: FormalType(formalType) {}
Signature getSignature(IRGenModule &IGM) const;
};
/// The @thin function type-info class.
class ThinFuncTypeInfo : public PODSingleScalarTypeInfo<ThinFuncTypeInfo,
LoadableTypeInfo>,
public FuncSignatureInfo {
ThinFuncTypeInfo(CanSILFunctionType formalType, llvm::Type *storageType,
Size size, Alignment align,
const SpareBitVector &spareBits)
: PODSingleScalarTypeInfo(storageType, size, spareBits, align),
FuncSignatureInfo(formalType)
{
}
public:
static const ThinFuncTypeInfo *create(CanSILFunctionType formalType,
llvm::Type *storageType,
Size size, Alignment align,
const SpareBitVector &spareBits) {
return new ThinFuncTypeInfo(formalType, storageType, size, align,
spareBits);
}
TypeLayoutEntry *buildTypeLayoutEntry(IRGenModule &IGM,
SILType T) const override {
return IGM.typeLayoutCache.getOrCreateScalarEntry(*this, T);
}
bool mayHaveExtraInhabitants(IRGenModule &IGM) const override {
return true;
}
unsigned getFixedExtraInhabitantCount(IRGenModule &IGM) const override {
return getFunctionPointerExtraInhabitantCount(IGM);
}
APInt getFixedExtraInhabitantValue(IRGenModule &IGM,
unsigned bits,
unsigned index) const override {
return getFunctionPointerFixedExtraInhabitantValue(IGM, bits, index, 0);
}
llvm::Value *getExtraInhabitantIndex(IRGenFunction &IGF, Address src,
SILType T, bool isOutlined)
const override {
return getFunctionPointerExtraInhabitantIndex(IGF, src);
}
void storeExtraInhabitant(IRGenFunction &IGF, llvm::Value *index,
Address dest, SILType T, bool isOutlined)
const override {
return storeFunctionPointerExtraInhabitant(IGF, index, dest);
}
};
/// The @thick function type-info class.
class FuncTypeInfo :
public ScalarPairTypeInfo<FuncTypeInfo, ReferenceTypeInfo>,
public FuncSignatureInfo {
protected:
FuncTypeInfo(CanSILFunctionType formalType, llvm::StructType *storageType,
Size size, Alignment align, SpareBitVector &&spareBits,
IsPOD_t pod)
: ScalarPairTypeInfo(storageType, size, std::move(spareBits), align, pod),
FuncSignatureInfo(formalType)
{
}
public:
static const FuncTypeInfo *create(CanSILFunctionType formalType,
llvm::StructType *storageType,
Size size, Alignment align,
SpareBitVector &&spareBits,
IsPOD_t pod) {
return new FuncTypeInfo(formalType, storageType, size, align,
std::move(spareBits), pod);
}
// Function types do not satisfy allowsOwnership.
#define REF_STORAGE(Name, name, ...) \
const TypeInfo * \
create##Name##StorageType(TypeConverter &TC, \
bool isOptional) const override { \
llvm_unreachable("[" #name "] function type"); \
}
#include "swift/AST/ReferenceStorage.def"
TypeLayoutEntry *buildTypeLayoutEntry(IRGenModule &IGM,
SILType T) const override {
return IGM.typeLayoutCache.getOrCreateScalarEntry(*this, T);
}
static Size getFirstElementSize(IRGenModule &IGM) {
return IGM.getPointerSize();
}
static StringRef getFirstElementLabel() {
return ".fn";
}
static bool isFirstElementTrivial() {
return true;
}
void emitRetainFirstElement(IRGenFunction &IGF, llvm::Value *fn,
Optional<Atomicity> atomicity = None) const {}
void emitReleaseFirstElement(IRGenFunction &IGF, llvm::Value *fn,
Optional<Atomicity> atomicity = None) const {}
void emitAssignFirstElement(IRGenFunction &IGF, llvm::Value *fn,
Address fnAddr) const {
IGF.Builder.CreateStore(fn, fnAddr);
}
static Size getSecondElementOffset(IRGenModule &IGM) {
return IGM.getPointerSize();
}
static Size getSecondElementSize(IRGenModule &IGM) {
return IGM.getPointerSize();
}
static StringRef getSecondElementLabel() {
return ".data";
}
bool isSecondElementTrivial() const {
return isPOD(ResilienceExpansion::Maximal);
}
void emitRetainSecondElement(IRGenFunction &IGF, llvm::Value *data,
Optional<Atomicity> atomicity = None) const {
if (!isPOD(ResilienceExpansion::Maximal)) {
if (!atomicity) atomicity = IGF.getDefaultAtomicity();
IGF.emitNativeStrongRetain(data, *atomicity);
}
}
void emitReleaseSecondElement(IRGenFunction &IGF, llvm::Value *data,
Optional<Atomicity> atomicity = None) const {
if (!isPOD(ResilienceExpansion::Maximal)) {
if (!atomicity) atomicity = IGF.getDefaultAtomicity();
IGF.emitNativeStrongRelease(data, *atomicity);
}
}
void emitAssignSecondElement(IRGenFunction &IGF, llvm::Value *context,
Address dataAddr) const {
if (isPOD(ResilienceExpansion::Maximal))
IGF.Builder.CreateStore(context, dataAddr);
else
IGF.emitNativeStrongAssign(context, dataAddr);
}
Address projectFunction(IRGenFunction &IGF, Address address) const {
return projectFirstElement(IGF, address);
}
Address projectData(IRGenFunction &IGF, Address address) const {
return IGF.Builder.CreateStructGEP(address, 1, IGF.IGM.getPointerSize(),
address->getName() + ".data");
}
void strongRetain(IRGenFunction &IGF, Explosion &e,
Atomicity atomicity) const override {
e.claimNext();
emitRetainSecondElement(IGF, e.claimNext(), atomicity);
}
void strongRelease(IRGenFunction &IGF, Explosion &e,
Atomicity atomicity) const override {
e.claimNext();
emitReleaseSecondElement(IGF, e.claimNext(), atomicity);
}
#define NEVER_LOADABLE_CHECKED_REF_STORAGE(Name, name, ...) \
void name##LoadStrong(IRGenFunction &IGF, Address src, \
Explosion &out, bool isOptional) const override { \
llvm_unreachable(#name " references to functions are not supported"); \
} \
void name##TakeStrong(IRGenFunction &IGF, Address src, \
Explosion &out, bool isOptional) const override { \
llvm_unreachable(#name " references to functions are not supported"); \
} \
void name##Init(IRGenFunction &IGF, Explosion &in, \
Address dest, bool isOptional) const override { \
llvm_unreachable(#name " references to functions are not supported"); \
} \
void name##Assign(IRGenFunction &IGF, Explosion &in, \
Address dest, bool isOptional) const override { \
llvm_unreachable(#name " references to functions are not supported"); \
}
#define ALWAYS_LOADABLE_CHECKED_REF_STORAGE(Name, name, ...) \
void strongRetain##Name(IRGenFunction &IGF, Explosion &e, \
Atomicity atomicity) const override { \
llvm_unreachable(#name " references to functions are not supported"); \
} \
void strongRetain##Name##Release(IRGenFunction &IGF, \
Explosion &e, \
Atomicity atomicity) const override { \
llvm_unreachable(#name " references to functions are not supported"); \
} \
void name##Retain(IRGenFunction &IGF, Explosion &e, \
Atomicity atomicity) const override { \
llvm_unreachable(#name " references to functions are not supported"); \
} \
void name##Release(IRGenFunction &IGF, Explosion &e, \
Atomicity atomicity) const override { \
llvm_unreachable(#name " references to functions are not supported"); \
}
#define SOMETIMES_LOADABLE_CHECKED_REF_STORAGE(Name, name, ...) \
NEVER_LOADABLE_CHECKED_REF_STORAGE(Name, name, "...") \
ALWAYS_LOADABLE_CHECKED_REF_STORAGE(Name, name, "...")
#include "swift/AST/ReferenceStorage.def"
bool mayHaveExtraInhabitants(IRGenModule &IGM) const override {
return true;
}
unsigned getFixedExtraInhabitantCount(IRGenModule &IGM) const override {
return getFunctionPointerExtraInhabitantCount(IGM);
}
APInt getFixedExtraInhabitantValue(IRGenModule &IGM,
unsigned bits,
unsigned index) const override {
return getFunctionPointerFixedExtraInhabitantValue(IGM, bits, index, 0);
}
llvm::Value *getExtraInhabitantIndex(IRGenFunction &IGF, Address src,
SILType T, bool isOutlined)
const override {
src = projectFunction(IGF, src);
return getFunctionPointerExtraInhabitantIndex(IGF, src);
}
APInt getFixedExtraInhabitantMask(IRGenModule &IGM) const override {
// Only the function pointer value is used for extra inhabitants.
auto pointerSize = IGM.getPointerSize();
auto mask = BitPatternBuilder(IGM.Triple.isLittleEndian());
mask.appendSetBits(pointerSize.getValueInBits());
mask.appendClearBits(pointerSize.getValueInBits());
return mask.build().getValue();
}
void storeExtraInhabitant(IRGenFunction &IGF, llvm::Value *index,
Address dest, SILType T, bool isOutlined)
const override {
dest = projectFunction(IGF, dest);
return storeFunctionPointerExtraInhabitant(IGF, index, dest);
}
};
/// The type-info class for ObjC blocks, which are represented by an ObjC
/// heap pointer.
class BlockTypeInfo : public HeapTypeInfo<BlockTypeInfo>,
public FuncSignatureInfo
{
public:
BlockTypeInfo(CanSILFunctionType ty,
llvm::PointerType *storageType,
Size size, SpareBitVector spareBits, Alignment align)
: HeapTypeInfo(storageType, size, spareBits, align),
FuncSignatureInfo(ty)
{
}
ReferenceCounting getReferenceCounting() const {
return ReferenceCounting::Block;
}
TypeLayoutEntry *buildTypeLayoutEntry(IRGenModule &IGM,
SILType T) const override {
return IGM.typeLayoutCache.getOrCreateScalarEntry(*this, T);
}
};
/// The type info class for the on-stack representation of an ObjC block.
///
/// TODO: May not be fixed-layout if we capture generics.
class BlockStorageTypeInfo final
: public IndirectTypeInfo<BlockStorageTypeInfo, FixedTypeInfo>
{
Size CaptureOffset;
public:
BlockStorageTypeInfo(llvm::Type *type, Size size, Alignment align,
SpareBitVector &&spareBits,
IsPOD_t pod, IsBitwiseTakable_t bt, Size captureOffset)
: IndirectTypeInfo(type, size, std::move(spareBits), align, pod, bt,
IsFixedSize),
CaptureOffset(captureOffset)
{}
TypeLayoutEntry *buildTypeLayoutEntry(IRGenModule &IGM,
SILType T) const override {
return IGM.typeLayoutCache.getOrCreateScalarEntry(*this, T);
}
// The lowered type should be an LLVM struct comprising the block header
// (IGM.ObjCBlockStructTy) as its first element and the capture as its
// second.
Address projectBlockHeader(IRGenFunction &IGF, Address storage) const {
return IGF.Builder.CreateStructGEP(storage, 0, Size(0));
}
Address projectCapture(IRGenFunction &IGF, Address storage) const {
return IGF.Builder.CreateStructGEP(storage, 1, CaptureOffset);
}
// TODO
// The frontend will currently never emit copy_addr or destroy_addr for
// block storage.
void assignWithCopy(IRGenFunction &IGF, Address dest, Address src,
SILType T, bool isOutlined) const override {
IGF.unimplemented(SourceLoc(), "copying @block_storage");
}
void initializeWithCopy(IRGenFunction &IGF, Address dest, Address src,
SILType T, bool isOutlined) const override {
IGF.unimplemented(SourceLoc(), "copying @block_storage");
}
void destroy(IRGenFunction &IGF, Address addr, SILType T,
bool isOutlined) const override {
IGF.unimplemented(SourceLoc(), "destroying @block_storage");
}
};
} // end anonymous namespace
const TypeInfo *TypeConverter::convertBlockStorageType(SILBlockStorageType *T) {
// The block storage consists of the block header (ObjCBlockStructTy)
// followed by the lowered type of the capture.
auto &capture = IGM.getTypeInfoForLowered(T->getCaptureType());
// TODO: Support dynamic-sized captures.
const auto *fixedCapture = dyn_cast<FixedTypeInfo>(&capture);
llvm::Type *fixedCaptureTy;
// The block header is pointer aligned. The capture may be worse aligned.
Alignment align = IGM.getPointerAlignment();
Size captureOffset(
IGM.DataLayout.getStructLayout(IGM.ObjCBlockStructTy)->getSizeInBytes());
auto spareBits = BitPatternBuilder(IGM.Triple.isLittleEndian());
spareBits.appendClearBits(captureOffset.getValueInBits());
Size size = captureOffset;
IsPOD_t pod = IsNotPOD;
IsBitwiseTakable_t bt = IsNotBitwiseTakable;
if (!fixedCapture) {
IGM.unimplemented(SourceLoc(), "dynamic @block_storage capture");
fixedCaptureTy = llvm::StructType::get(IGM.getLLVMContext(), {});
} else {
fixedCaptureTy = cast<FixedTypeInfo>(capture).getStorageType();
align = std::max(align, fixedCapture->getFixedAlignment());
captureOffset = captureOffset.roundUpToAlignment(align);
spareBits.padWithSetBitsTo(captureOffset.getValueInBits());
spareBits.append(fixedCapture->getSpareBits());
size = captureOffset + fixedCapture->getFixedSize();
pod = fixedCapture->isPOD(ResilienceExpansion::Maximal);
bt = fixedCapture->isBitwiseTakable(ResilienceExpansion::Maximal);
}
llvm::Type *storageElts[] = {
IGM.ObjCBlockStructTy,
fixedCaptureTy,
};
auto storageTy = llvm::StructType::get(IGM.getLLVMContext(), storageElts,
/*packed*/ false);
return new BlockStorageTypeInfo(storageTy, size, align, spareBits.build(),
pod, bt, captureOffset);
}
Address irgen::projectBlockStorageCapture(IRGenFunction &IGF,
Address storageAddr,
CanSILBlockStorageType storageTy) {
auto &tl = IGF.getTypeInfoForLowered(storageTy).as<BlockStorageTypeInfo>();
return tl.projectCapture(IGF, storageAddr);
}
const TypeInfo *TypeConverter::convertFunctionType(SILFunctionType *T) {
// Handle `@differentiable` and `@differentiable(linear)` functions.
switch (T->getDifferentiabilityKind()) {
case DifferentiabilityKind::Normal:
return convertNormalDifferentiableFunctionType(T);
case DifferentiabilityKind::Linear:
return convertLinearDifferentiableFunctionType(T);
case DifferentiabilityKind::NonDifferentiable:
break;
}
switch (T->getRepresentation()) {
case SILFunctionType::Representation::Block:
return new BlockTypeInfo(CanSILFunctionType(T),
IGM.ObjCBlockPtrTy,
IGM.getPointerSize(),
IGM.getHeapObjectSpareBits(),
IGM.getPointerAlignment());
case SILFunctionType::Representation::Thin:
case SILFunctionType::Representation::Method:
case SILFunctionType::Representation::WitnessMethod:
case SILFunctionType::Representation::ObjCMethod:
case SILFunctionType::Representation::CFunctionPointer:
case SILFunctionType::Representation::Closure:
return ThinFuncTypeInfo::create(CanSILFunctionType(T),
IGM.FunctionPtrTy,
IGM.getPointerSize(),
IGM.getPointerAlignment(),
IGM.getFunctionPointerSpareBits());
case SILFunctionType::Representation::Thick: {
SpareBitVector spareBits;
spareBits.append(IGM.getFunctionPointerSpareBits());
// Although the context pointer of a closure (at least, an escaping one)
// is a refcounted pointer, we'd like to reserve the right to pack small
// contexts into the pointer value, so let's not take any spare bits from
// it.
spareBits.appendClearBits(IGM.getPointerSize().getValueInBits());
if (T->isNoEscape()) {
// @noescape thick functions are trivial types.
return FuncTypeInfo::create(
CanSILFunctionType(T), IGM.NoEscapeFunctionPairTy,
IGM.getPointerSize() * 2, IGM.getPointerAlignment(),
std::move(spareBits), IsPOD);
}
return FuncTypeInfo::create(
CanSILFunctionType(T), IGM.FunctionPairTy, IGM.getPointerSize() * 2,
IGM.getPointerAlignment(), std::move(spareBits), IsNotPOD);
}
}
llvm_unreachable("bad function type representation");
}
Signature FuncSignatureInfo::getSignature(IRGenModule &IGM) const {
// If it's already been filled in, we're done.
if (TheSignature.isValid())
return TheSignature;
// Update the cache and return.
TheSignature = Signature::getUncached(IGM, FormalType);
assert(TheSignature.isValid());
return TheSignature;
}
static const FuncSignatureInfo &
getFuncSignatureInfoForLowered(IRGenModule &IGM, CanSILFunctionType type) {
auto &ti = IGM.getTypeInfoForLowered(type);
switch (type->getRepresentation()) {
case SILFunctionType::Representation::Block:
return ti.as<BlockTypeInfo>();
case SILFunctionType::Representation::Thin:
case SILFunctionType::Representation::CFunctionPointer:
case SILFunctionType::Representation::Method:
case SILFunctionType::Representation::WitnessMethod:
case SILFunctionType::Representation::ObjCMethod:
case SILFunctionType::Representation::Closure:
return ti.as<ThinFuncTypeInfo>();
case SILFunctionType::Representation::Thick:
return ti.as<FuncTypeInfo>();
}
llvm_unreachable("bad function type representation");
}
Signature
IRGenModule::getSignature(CanSILFunctionType type) {
auto &sigInfo = getFuncSignatureInfoForLowered(*this, type);
return sigInfo.getSignature(*this);
}
llvm::FunctionType *
IRGenModule::getFunctionType(CanSILFunctionType type,
llvm::AttributeList &attrs,
ForeignFunctionInfo *foreignInfo) {
auto &sigInfo = getFuncSignatureInfoForLowered(*this, type);
Signature sig = sigInfo.getSignature(*this);
attrs = sig.getAttributes();
if (foreignInfo) *foreignInfo = sig.getForeignInfo();
return sig.getType();
}
ForeignFunctionInfo
IRGenModule::getForeignFunctionInfo(CanSILFunctionType type) {
if (type->getLanguage() == SILFunctionLanguage::Swift)
return ForeignFunctionInfo();
auto &sigInfo = getFuncSignatureInfoForLowered(*this, type);
return sigInfo.getSignature(*this).getForeignInfo();
}
static void emitApplyArgument(IRGenFunction &IGF,
CanSILFunctionType origFnTy,
SILParameterInfo origParam,
CanSILFunctionType substFnTy,
SILParameterInfo substParam,
Explosion &in,
Explosion &out) {
auto silConv = IGF.IGM.silConv;
auto context = IGF.IGM.getMaximalTypeExpansionContext();
bool isSubstituted =
(silConv.getSILType(substParam, substFnTy, context)
!= silConv.getSILType(origParam, origFnTy, context));
// For indirect arguments, we just need to pass a pointer.
if (silConv.isSILIndirect(origParam)) {
// This address is of the substituted type.
auto addr = in.claimNext();
// If a substitution is in play, just bitcast the address.
if (isSubstituted) {
auto origType = IGF.IGM.getStoragePointerType(
silConv.getSILType(origParam, origFnTy, context));
addr = IGF.Builder.CreateBitCast(addr, origType);
}
out.add(addr);
return;
}
assert(!silConv.isSILIndirect(origParam)
&& "Unexpected opaque apply parameter.");
// Otherwise, it's an explosion, which we may need to translate,
// both in terms of explosion level and substitution levels.
// Handle the last unsubstituted case.
if (!isSubstituted) {
auto &substArgTI = cast<LoadableTypeInfo>(
IGF.getTypeInfo(silConv.getSILType(substParam, substFnTy, context)));
substArgTI.reexplode(IGF, in, out);
return;
}
reemitAsUnsubstituted(IGF, silConv.getSILType(origParam, origFnTy, context),
silConv.getSILType(substParam, substFnTy, context), in,
out);
}
CanType irgen::getArgumentLoweringType(CanType type, SILParameterInfo paramInfo,
bool isNoEscape) {
switch (paramInfo.getConvention()) {
// Capture value parameters by value, consuming them.
case ParameterConvention::Direct_Owned:
case ParameterConvention::Direct_Unowned:
case ParameterConvention::Direct_Guaranteed:
return type;
// Capture indirect parameters if the closure is not [onstack]. [onstack]
// closures don't take ownership of their arguments so we just capture the
// address.
case ParameterConvention::Indirect_In:
case ParameterConvention::Indirect_In_Constant:
case ParameterConvention::Indirect_In_Guaranteed:
if (isNoEscape)
return CanInOutType::get(type);
else
return type;
// Capture inout parameters by pointer.
case ParameterConvention::Indirect_Inout:
case ParameterConvention::Indirect_InoutAliasable:
return CanInOutType::get(type);
}
llvm_unreachable("unhandled convention");
}
static bool isABIIgnoredParameterWithoutStorage(IRGenModule &IGM,
IRGenFunction &IGF,
CanSILFunctionType substType,
unsigned paramIdx) {
auto param = substType->getParameters()[paramIdx];
if (param.isFormalIndirect())
return false;
SILType argType = IGM.silConv.getSILType(
param, substType, IGM.getMaximalTypeExpansionContext());
auto &ti = IGF.getTypeInfoForLowered(argType.getASTType());
// Empty values don't matter.
return ti.getSchema().empty();
}
/// Find the parameter index for the one (assuming there was only one) partially
/// applied argument ignoring empty types that are not passed as part of the
/// ABI.
static unsigned findSinglePartiallyAppliedParameterIndexIgnoringEmptyTypes(
IRGenFunction &IGF, CanSILFunctionType substType,
CanSILFunctionType outType) {
auto substParameters = substType->getParameters();
auto outParamters = outType->getParameters();
unsigned firstNonEmpty = -1U;
for (unsigned paramIdx = outParamters.size() ; paramIdx != substParameters.size(); ++paramIdx) {
bool isEmpty =
isABIIgnoredParameterWithoutStorage(IGF.IGM, IGF, substType, paramIdx);
assert((isEmpty || firstNonEmpty == -1U) && "Expect at most one partially "
"applied that is passed as an "
"ABI argument");
if (!isEmpty)
firstNonEmpty = paramIdx;
}
assert(firstNonEmpty != -1U);
return firstNonEmpty;
}
namespace {
class PartialApplicationForwarderEmission {
protected:
IRGenModule &IGM;
IRGenFunction &subIGF;
llvm::Function *fwd;
const Optional<FunctionPointer> &staticFnPtr;
bool calleeHasContext;
const Signature &origSig;
CanSILFunctionType origType;
CanSILFunctionType substType;
CanSILFunctionType outType;
SubstitutionMap subs;
HeapLayout const *layout;
const ArrayRef<ParameterConvention> conventions;
SILFunctionConventions origConv;
SILFunctionConventions outConv;
Explosion origParams;
PartialApplicationForwarderEmission(
IRGenModule &IGM, IRGenFunction &subIGF, llvm::Function *fwd,
const Optional<FunctionPointer> &staticFnPtr, bool calleeHasContext,
const Signature &origSig, CanSILFunctionType origType,
CanSILFunctionType substType, CanSILFunctionType outType,
SubstitutionMap subs, HeapLayout const *layout,
ArrayRef<ParameterConvention> conventions)
: IGM(IGM), subIGF(subIGF), fwd(fwd), staticFnPtr(staticFnPtr),
calleeHasContext(calleeHasContext), origSig(origSig),
origType(origType), substType(substType), outType(outType), subs(subs),
conventions(conventions), origConv(origType, IGM.getSILModule()),
outConv(outType, IGM.getSILModule()),
origParams(subIGF.collectParameters()) {}
public:
enum class DynamicFunctionKind {
Witness,
PartialApply,
};
virtual void begin(){};
virtual void gatherArgumentsFromApply() = 0;
virtual unsigned getCurrentArgumentIndex() = 0;
virtual bool transformArgumentToNative(SILParameterInfo origParamInfo,
Explosion &in, Explosion &out) = 0;
virtual void addArgument(Explosion &explosion) = 0;
virtual void addArgument(llvm::Value *argValue) = 0;
virtual void addArgument(Explosion &explosion, unsigned index) = 0;
virtual void addArgument(llvm::Value *argValue, unsigned index) = 0;
virtual SILParameterInfo getParameterInfo(unsigned index) = 0;
virtual llvm::Value *getContext() = 0;
virtual llvm::Value *getDynamicFunctionPointer(PointerAuthInfo &authInfo) = 0;
virtual llvm::Value *getDynamicFunctionContext() = 0;
virtual void addDynamicFunctionContext(Explosion &explosion,
DynamicFunctionKind kind) = 0;
virtual void addDynamicFunctionPointer(Explosion &explosion,
DynamicFunctionKind kind) = 0;
virtual void addSelf(Explosion &explosion) = 0;
virtual void addWitnessSelfMetadata(llvm::Value *value) = 0;
virtual void addWitnessSelfWitnessTable(llvm::Value *value) = 0;
virtual void forwardErrorResult() = 0;
virtual bool originalParametersConsumed() = 0;
virtual void addPolymorphicArguments(Explosion polyArgs) = 0;
virtual llvm::CallInst *createCall(FunctionPointer &fnPtr) = 0;
virtual void createReturn(llvm::CallInst *call) = 0;
virtual void end(){};
virtual ~PartialApplicationForwarderEmission() {}
};
class SyncPartialApplicationForwarderEmission
: public PartialApplicationForwarderEmission {
using super = PartialApplicationForwarderEmission;
// Create a new explosion for potentially reabstracted parameters.
Explosion args;
Address resultValueAddr;
public:
SyncPartialApplicationForwarderEmission(
IRGenModule &IGM, IRGenFunction &subIGF, llvm::Function *fwd,
const Optional<FunctionPointer> &staticFnPtr, bool calleeHasContext,
const Signature &origSig, CanSILFunctionType origType,
CanSILFunctionType substType, CanSILFunctionType outType,
SubstitutionMap subs, HeapLayout const *layout,
ArrayRef<ParameterConvention> conventions)
: PartialApplicationForwarderEmission(
IGM, subIGF, fwd, staticFnPtr, calleeHasContext, origSig, origType,
substType, outType, subs, layout, conventions) {}
void begin() override { super::begin(); }
void gatherArgumentsFromApply() override {
// Lower the forwarded arguments in the original function's generic context.
GenericContextScope scope(IGM, origType->getInvocationGenericSignature());
SILFunctionConventions origConv(origType, IGM.getSILModule());
auto &outResultTI = IGM.getTypeInfo(
outConv.getSILResultType(IGM.getMaximalTypeExpansionContext()));
auto &nativeResultSchema = outResultTI.nativeReturnValueSchema(IGM);
auto &origResultTI = IGM.getTypeInfo(
origConv.getSILResultType(IGM.getMaximalTypeExpansionContext()));
auto &origNativeSchema = origResultTI.nativeReturnValueSchema(IGM);
// Forward the indirect return values. We might have to reabstract the
// return value.
if (nativeResultSchema.requiresIndirect()) {
assert(origNativeSchema.requiresIndirect());
auto resultAddr = origParams.claimNext();
resultAddr = subIGF.Builder.CreateBitCast(
resultAddr, IGM.getStoragePointerType(origConv.getSILResultType(
IGM.getMaximalTypeExpansionContext())));
args.add(resultAddr);
} else if (origNativeSchema.requiresIndirect()) {
assert(!nativeResultSchema.requiresIndirect());
auto stackAddr = outResultTI.allocateStack(
subIGF,
outConv.getSILResultType(IGM.getMaximalTypeExpansionContext()),
"return.temp");
resultValueAddr = stackAddr.getAddress();
auto resultAddr = subIGF.Builder.CreateBitCast(
resultValueAddr, IGM.getStoragePointerType(origConv.getSILResultType(
IGM.getMaximalTypeExpansionContext())));
args.add(resultAddr.getAddress());
}
for (auto resultType : origConv.getIndirectSILResultTypes(
IGM.getMaximalTypeExpansionContext())) {
auto addr = origParams.claimNext();
addr = subIGF.Builder.CreateBitCast(
addr, IGM.getStoragePointerType(resultType));
args.add(addr);
}
// Reemit the parameters as unsubstituted.
for (unsigned i = 0; i < outType->getParameters().size(); ++i) {
auto origParamInfo = origType->getParameters()[i];
auto &ti = IGM.getTypeInfoForLowered(origParamInfo.getArgumentType(
IGM.getSILModule(), origType, IGM.getMaximalTypeExpansionContext()));
auto schema = ti.getSchema();
auto origParamSILType = IGM.silConv.getSILType(
origParamInfo, origType, IGM.getMaximalTypeExpansionContext());
// Forward the address of indirect value params.
auto &nativeSchemaOrigParam = ti.nativeParameterValueSchema(IGM);
bool isIndirectParam = origConv.isSILIndirect(origParamInfo);
if (!isIndirectParam && nativeSchemaOrigParam.requiresIndirect()) {
auto addr = origParams.claimNext();
if (addr->getType() != ti.getStorageType()->getPointerTo())
addr = subIGF.Builder.CreateBitCast(addr,
ti.getStorageType()->getPointerTo());
args.add(addr);
continue;
}
auto outTypeParamInfo = outType->getParameters()[i];
// Indirect parameters need no mapping through the native calling
// convention.
if (isIndirectParam) {
emitApplyArgument(subIGF,
origType,
origParamInfo,
outType,
outTypeParamInfo,
origParams, args);
continue;
}
// Map from the native calling convention into the explosion schema.
auto outTypeParamSILType = IGM.silConv.getSILType(
origParamInfo, origType, IGM.getMaximalTypeExpansionContext());
auto &nativeSchemaOutTypeParam =
IGM.getTypeInfo(outTypeParamSILType).nativeParameterValueSchema(IGM);
Explosion nativeParam;
origParams.transferInto(nativeParam, nativeSchemaOutTypeParam.size());
bindPolymorphicParameter(subIGF, origType, substType, nativeParam, i);
Explosion nonNativeParam = nativeSchemaOutTypeParam.mapFromNative(
subIGF.IGM, subIGF, nativeParam, outTypeParamSILType);
assert(nativeParam.empty());
// Emit unsubstituted argument for call.
Explosion nonNativeApplyArg;
emitApplyArgument(subIGF,
origType, origParamInfo,
outType, outTypeParamInfo,
nonNativeParam,
nonNativeApplyArg);
assert(nonNativeParam.empty());
// Map back from the explosion scheme to the native calling convention for
// the call.
Explosion nativeApplyArg = nativeSchemaOrigParam.mapIntoNative(
subIGF.IGM, subIGF, nonNativeApplyArg, origParamSILType, false);
assert(nonNativeApplyArg.empty());
nativeApplyArg.transferInto(args, nativeApplyArg.size());
}
}
unsigned getCurrentArgumentIndex() override { return args.size(); }
bool transformArgumentToNative(SILParameterInfo origParamInfo, Explosion &in,
Explosion &out) override {
return addNativeArgument(subIGF, in, origType, origParamInfo, out, false);
}
void addArgument(Explosion &explosion) override {
args.add(explosion.claimAll());
}
void addArgument(llvm::Value *argValue) override { args.add(argValue); }
void addArgument(Explosion &explosion, unsigned index) override {
addArgument(explosion);
}
void addArgument(llvm::Value *argValue, unsigned index) override {
addArgument(argValue);
}
SILParameterInfo getParameterInfo(unsigned index) override {
return substType->getParameters()[index];
}
llvm::Value *getContext() override { return origParams.claimNext(); }
llvm::Value *getDynamicFunctionPointer(PointerAuthInfo &authInfo) override {
return args.takeLast();
}
llvm::Value *getDynamicFunctionContext() override { return args.takeLast(); }
void addDynamicFunctionContext(Explosion &explosion,
DynamicFunctionKind kind) override {
addArgument(explosion);
}
void addDynamicFunctionPointer(Explosion &explosion,
DynamicFunctionKind kind) override {
addArgument(explosion);
}
void addSelf(Explosion &explosion) override { addArgument(explosion); }
void addWitnessSelfMetadata(llvm::Value *value) override {
addArgument(value);
}
void addWitnessSelfWitnessTable(llvm::Value *value) override {
addArgument(value);
}
void forwardErrorResult() override {
llvm::Value *errorResultPtr = origParams.claimNext();
args.add(errorResultPtr);
}
bool originalParametersConsumed() override { return origParams.empty(); }
void addPolymorphicArguments(Explosion polyArgs) override {
polyArgs.transferInto(args, polyArgs.size());
}
llvm::CallInst *createCall(FunctionPointer &fnPtr) override {
return subIGF.Builder.CreateCall(fnPtr, args.claimAll());
}
void createReturn(llvm::CallInst *call) override {
// Reabstract the result value as substituted.
SILFunctionConventions origConv(origType, IGM.getSILModule());
auto &outResultTI = IGM.getTypeInfo(
outConv.getSILResultType(IGM.getMaximalTypeExpansionContext()));
auto &nativeResultSchema = outResultTI.nativeReturnValueSchema(IGM);
if (call->getType()->isVoidTy()) {
if (!resultValueAddr.isValid())
subIGF.Builder.CreateRetVoid();
else {
// Okay, we have called a function that expects an indirect return type
// but the partially applied return type is direct.
assert(!nativeResultSchema.requiresIndirect());
Explosion loadedResult;
cast<LoadableTypeInfo>(outResultTI)
.loadAsTake(subIGF, resultValueAddr, loadedResult);
Explosion nativeResult = nativeResultSchema.mapIntoNative(
IGM, subIGF, loadedResult,
outConv.getSILResultType(IGM.getMaximalTypeExpansionContext()),
false);
outResultTI.deallocateStack(
subIGF, resultValueAddr,
outConv.getSILResultType(IGM.getMaximalTypeExpansionContext()));
if (nativeResult.size() == 1)
subIGF.Builder.CreateRet(nativeResult.claimNext());
else {
llvm::Value *nativeAgg =
llvm::UndefValue::get(nativeResultSchema.getExpandedType(IGM));
for (unsigned i = 0, e = nativeResult.size(); i != e; ++i) {
auto *elt = nativeResult.claimNext();
nativeAgg = subIGF.Builder.CreateInsertValue(nativeAgg, elt, i);
}
subIGF.Builder.CreateRet(nativeAgg);
}
}
} else {
llvm::Value *callResult = call;
// If the result type is dependent on a type parameter we might have to
// cast to the result type - it could be substituted.
if (origConv.getSILResultType(IGM.getMaximalTypeExpansionContext())
.hasTypeParameter()) {
auto ResType = fwd->getReturnType();
if (ResType != callResult->getType())
callResult =
subIGF.coerceValue(callResult, ResType, subIGF.IGM.DataLayout);
}
subIGF.Builder.CreateRet(callResult);
}
}
void end() override { super::end(); }
};
class AsyncPartialApplicationForwarderEmission
: public PartialApplicationForwarderEmission {
using super = PartialApplicationForwarderEmission;
AsyncContextLayout layout;
llvm::Value *task;
llvm::Value *executor;
llvm::Value *contextBuffer;
Size contextSize;
Address context;
unsigned currentArgumentIndex;
struct DynamicFunction {
using Kind = DynamicFunctionKind;
Kind kind;
llvm::Value *pointer;
llvm::Value *context;
};
Optional<DynamicFunction> dynamicFunction = llvm::None;
struct Self {
enum class Kind {
Method,
WitnessMethod,
};
Kind kind;
llvm::Value *value;
};
Optional<Self> self = llvm::None;
llvm::Value *loadValue(ElementLayout layout) {
Address addr = layout.project(subIGF, context, /*offsets*/ llvm::None);
auto &ti = cast<LoadableTypeInfo>(layout.getType());
Explosion explosion;
ti.loadAsTake(subIGF, addr, explosion);
return explosion.claimNext();
}
void saveValue(ElementLayout layout, Explosion &explosion) {
Address addr = layout.project(subIGF, context, /*offsets*/ llvm::None);
auto &ti = cast<LoadableTypeInfo>(layout.getType());
ti.initialize(subIGF, explosion, addr, /*isOutlined*/ false);
}
void loadValue(ElementLayout layout, Explosion &explosion) {
Address addr = layout.project(subIGF, context, /*offsets*/ llvm::None);
auto &ti = cast<LoadableTypeInfo>(layout.getType());
ti.loadAsTake(subIGF, addr, explosion);
}
public:
AsyncPartialApplicationForwarderEmission(
IRGenModule &IGM, IRGenFunction &subIGF, llvm::Function *fwd,
const Optional<FunctionPointer> &staticFnPtr, bool calleeHasContext,
const Signature &origSig, CanSILFunctionType origType,
CanSILFunctionType substType, CanSILFunctionType outType,
SubstitutionMap subs, HeapLayout const *layout,
ArrayRef<ParameterConvention> conventions)
: PartialApplicationForwarderEmission(
IGM, subIGF, fwd, staticFnPtr, calleeHasContext, origSig, origType,
substType, outType, subs, layout, conventions),
layout(getAsyncContextLayout(subIGF.IGM, origType, substType, subs)),
currentArgumentIndex(outType->getNumParameters()) {
task = origParams.claimNext();
executor = origParams.claimNext();
contextBuffer = origParams.claimNext();
}
void begin() override {
super::begin();
assert(task);
assert(executor);
assert(contextBuffer);
context = layout.emitCastTo(subIGF, contextBuffer);
}
bool transformArgumentToNative(SILParameterInfo origParamInfo, Explosion &in,
Explosion &out) override {
out.add(in.claimAll());
return false;
}
unsigned getCurrentArgumentIndex() override { return currentArgumentIndex; }
void gatherArgumentsFromApply() override {
// The provided %swift.context* already contains all the values from the
// apply site. All that remains to do is bind polymorphic parameters.
for (unsigned index = 0; index < outType->getParameters().size(); ++index) {
auto fieldLayout = layout.getArgumentLayout(index);
Explosion explosion;
loadValue(fieldLayout, explosion);
bindPolymorphicParameter(subIGF, origType, substType, explosion, index);
(void)explosion.claimAll();
// TODO: Rather than just discard this explosion, avoid loading the
// parameters if no polymorphic binding is necessary.
}
}
void addArgument(llvm::Value *argValue) override {
addArgument(argValue, currentArgumentIndex);
}
void addArgument(Explosion &explosion) override {
addArgument(explosion, currentArgumentIndex);
}
void addArgument(llvm::Value *argValue, unsigned index) override {
Explosion explosion;
explosion.add(argValue);
addArgument(explosion, index);
}
void addArgument(Explosion &explosion, unsigned index) override {
currentArgumentIndex = index + 1;
auto isLocalContext = (hasSelfContextParameter(origType) &&
index == origType->getParameters().size() - 1);
if (isLocalContext) {
addSelf(explosion);
return;
}
auto fieldLayout = layout.getArgumentLayout(index);
saveValue(fieldLayout, explosion);
}
SILParameterInfo getParameterInfo(unsigned index) override {
return origType->getParameters()[index];
}
llvm::Value *getContext() override {
return loadValue(layout.getLocalContextLayout());
}
llvm::Value *getDynamicFunctionPointer(PointerAuthInfo &authInfo) override {
assert(dynamicFunction && dynamicFunction->pointer);
auto *context = dynamicFunction->context;
if (!context) {
return dynamicFunction->pointer;
}
auto *rawFunction = subIGF.Builder.CreateBitCast(
dynamicFunction->pointer, origSig.getType()->getPointerTo());
auto functionPointer =
FunctionPointer(FunctionPointer::KindTy::AsyncFunctionPointer,
rawFunction, authInfo, origSig);
llvm::Value *size = nullptr;
llvm::Value *function = nullptr;
std::tie(function, size) = getAsyncFunctionAndSize(
subIGF, origType->getRepresentation(), functionPointer, context,
{/*function*/ true, /*size*/ false});
assert(size == nullptr);
return function;
}
llvm::Value *getDynamicFunctionContext() override {
assert((dynamicFunction && dynamicFunction->context) ||
(self && self->value));
return dynamicFunction ? dynamicFunction->context : self->value;
}
void addDynamicFunctionContext(Explosion &explosion,
DynamicFunction::Kind kind) override {
auto *value = explosion.claimNext();
assert(explosion.empty());
if (dynamicFunction) {
assert(dynamicFunction->kind == kind);
if (dynamicFunction->context) {
assert(dynamicFunction->context == value);
} else {
dynamicFunction->context = value;
}
return;
}
dynamicFunction = {kind, /*pointer*/ nullptr, /*context*/ value};
}
void addDynamicFunctionPointer(Explosion &explosion,
DynamicFunction::Kind kind) override {
auto *value = explosion.claimNext();
assert(explosion.empty());
if (dynamicFunction) {
assert(dynamicFunction->kind == kind);
if (dynamicFunction->pointer) {
assert(dynamicFunction->pointer == value);
} else {
dynamicFunction->pointer = value;
}
return;
}
dynamicFunction = {kind, /*pointer*/ value, /*context*/ nullptr};
}
void addSelf(Explosion &explosion) override {
auto *value = explosion.claimNext();
assert(explosion.empty());
Self::Kind kind = [&](SILFunctionTypeRepresentation representation) {
switch (representation) {
case SILFunctionTypeRepresentation::Method:
return Self::Kind::Method;
case SILFunctionTypeRepresentation::WitnessMethod:
return Self::Kind::WitnessMethod;
default:
llvm_unreachable("representation does not have a self");
}
}(origType->getRepresentation());
if (self) {
assert(self->kind == kind);
if (self->value) {
assert(self->value == value);
} else {
self->value = value;
}
return;
}
self = {kind, value};
Explosion toSave;
toSave.add(value);
auto fieldLayout = layout.getLocalContextLayout();
saveValue(fieldLayout, toSave);
}
void addWitnessSelfMetadata(llvm::Value *value) override {
auto fieldLayout = layout.getSelfMetadataLayout();
Explosion explosion;
explosion.add(value);
saveValue(fieldLayout, explosion);
}
void addWitnessSelfWitnessTable(llvm::Value *value) override {
auto fieldLayout = layout.getSelfWitnessTableLayout();
Explosion explosion;
explosion.add(value);
saveValue(fieldLayout, explosion);
}
void forwardErrorResult() override {
// Nothing to do here. The error result pointer is already in the
// appropriate position.
}
bool originalParametersConsumed() override {
// The original parameters remain in the initially allocated
// %swift.context*, so they have always already been consumed.
return true;
}
void addPolymorphicArguments(Explosion polyArgs) override {
if (polyArgs.size() == 0) {
return;
}
assert(layout.hasBindings());
auto bindingsLayout = layout.getBindingsLayout();
auto bindingsAddr =
bindingsLayout.project(subIGF, context, /*offsets*/ None);
layout.getBindings().save(subIGF, bindingsAddr, polyArgs);
}
llvm::CallInst *createCall(FunctionPointer &fnPtr) override {
Explosion asyncExplosion;
asyncExplosion.add(subIGF.getAsyncTask());
asyncExplosion.add(subIGF.getAsyncExecutor());
asyncExplosion.add(contextBuffer);
if (dynamicFunction &&
dynamicFunction->kind == DynamicFunction::Kind::PartialApply) {
// Just before making the call, replace the old thick context with the
// new thick context so that (1) the new thick context is never used by
// this partial apply forwarder and (2) the old thick context is never
// used by the callee partial apply forwarder.
assert(dynamicFunction->context);
auto fieldLayout = layout.getLocalContextLayout();
Explosion explosion;
explosion.add(dynamicFunction->context);
saveValue(fieldLayout, explosion);
}
return subIGF.Builder.CreateCall(fnPtr.getAsFunction(subIGF),
asyncExplosion.claimAll());
}
void createReturn(llvm::CallInst *call) override {
subIGF.Builder.CreateRetVoid();
}
void end() override {
assert(context.isValid());
super::end();
}
};
std::unique_ptr<PartialApplicationForwarderEmission>
getPartialApplicationForwarderEmission(
IRGenModule &IGM, IRGenFunction &subIGF, llvm::Function *fwd,
const Optional<FunctionPointer> &staticFnPtr, bool calleeHasContext,
const Signature &origSig, CanSILFunctionType origType,
CanSILFunctionType substType, CanSILFunctionType outType,
SubstitutionMap subs, HeapLayout const *layout,
ArrayRef<ParameterConvention> conventions) {
if (origType->isAsync()) {
return std::make_unique<AsyncPartialApplicationForwarderEmission>(
IGM, subIGF, fwd, staticFnPtr, calleeHasContext, origSig, origType,
substType, outType, subs, layout, conventions);
} else {
return std::make_unique<SyncPartialApplicationForwarderEmission>(
IGM, subIGF, fwd, staticFnPtr, calleeHasContext, origSig, origType,
substType, outType, subs, layout, conventions);
}
}
} // end anonymous namespace
/// Emit the forwarding stub function for a partial application.
///
/// If 'layout' is null, there is a single captured value of
/// Swift-refcountable type that is being used directly as the
/// context object.
static llvm::Function *emitPartialApplicationForwarder(IRGenModule &IGM,
const Optional<FunctionPointer> &staticFnPtr,
bool calleeHasContext,
const Signature &origSig,
CanSILFunctionType origType,
CanSILFunctionType substType,
CanSILFunctionType outType,
SubstitutionMap subs,
HeapLayout const *layout,
ArrayRef<ParameterConvention> conventions) {
auto outSig = IGM.getSignature(outType);
llvm::AttributeList outAttrs = outSig.getAttributes();
llvm::FunctionType *fwdTy = outSig.getType();
SILFunctionConventions outConv(outType, IGM.getSILModule());
StringRef FnName;
if (staticFnPtr)
FnName = staticFnPtr->getName(IGM);
IRGenMangler Mangler;
std::string thunkName = Mangler.manglePartialApplyForwarder(FnName);
// FIXME: Maybe cache the thunk by function and closure types?.
llvm::Function *fwd =
llvm::Function::Create(fwdTy, llvm::Function::InternalLinkage,
llvm::StringRef(thunkName), &IGM.Module);
fwd->setCallingConv(outSig.getCallingConv());
fwd->setAttributes(outAttrs);
// Merge initial attributes with outAttrs.
llvm::AttrBuilder b;
IGM.constructInitialFnAttributes(b);
fwd->addAttributes(llvm::AttributeList::FunctionIndex, b);
IRGenFunction subIGF(IGM, fwd);
if (origType->isAsync())
subIGF.setupAsync();
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(subIGF, fwd);
auto emission = getPartialApplicationForwarderEmission(
IGM, subIGF, fwd, staticFnPtr, calleeHasContext, origSig, origType,
substType, outType, subs, layout, conventions);
emission->begin();
emission->gatherArgumentsFromApply();
struct AddressToDeallocate {
SILType Type;
const TypeInfo &TI;
StackAddress Addr;
};
SmallVector<AddressToDeallocate, 4> addressesToDeallocate;
bool dependsOnContextLifetime = false;
bool consumesContext;
bool needsAllocas = false;
switch (outType->getCalleeConvention()) {
case ParameterConvention::Direct_Owned:
consumesContext = true;
break;
case ParameterConvention::Direct_Unowned:
case ParameterConvention::Direct_Guaranteed:
consumesContext = false;
break;
case ParameterConvention::Indirect_Inout:
case ParameterConvention::Indirect_InoutAliasable:
case ParameterConvention::Indirect_In:
case ParameterConvention::Indirect_In_Constant:
case ParameterConvention::Indirect_In_Guaranteed:
llvm_unreachable("indirect callables not supported");
}
// Lower the captured arguments in the original function's generic context.
GenericContextScope scope(IGM, origType->getInvocationGenericSignature());
// This is where the context parameter appears.
llvm::Value *rawData = nullptr;
Address data;
unsigned nextCapturedField = 0;
if (!layout) {
rawData = emission->getContext();
} else if (!layout->isKnownEmpty()) {
rawData = emission->getContext();
data = layout->emitCastTo(subIGF, rawData);
if (origType->isAsync()) {
// Async layouts contain the size of the needed async context as their
// first element. It is not a parameter and needs to be skipped.
++nextCapturedField;
}
// Restore type metadata bindings, if we have them.
if (layout->hasBindings()) {
auto bindingLayout = layout->getElement(nextCapturedField++);
// The bindings should be fixed-layout inside the object, so we can
// pass None here. If they weren't, we'd have a chicken-egg problem.
auto bindingsAddr = bindingLayout.project(subIGF, data, /*offsets*/ None);
layout->getBindings().restore(subIGF, bindingsAddr,
MetadataState::Complete);
}
// There's still a placeholder to claim if the target type is thick
// or there's an error result.
} else if (outType->getRepresentation()==SILFunctionTypeRepresentation::Thick
|| outType->hasErrorResult()) {
llvm::Value *contextPtr = emission->getContext(); (void)contextPtr;
assert(contextPtr->getType() == IGM.RefCountedPtrTy);
}
Explosion polyArgs;
// Emit the polymorphic arguments.
assert((subs.hasAnySubstitutableParams()
== hasPolymorphicParameters(origType) ||
(!subs.hasAnySubstitutableParams() && origType->getRepresentation() ==
SILFunctionTypeRepresentation::WitnessMethod))
&& "should have substitutions iff original function is generic");
WitnessMetadata witnessMetadata;
// If we have a layout we might have to bind polymorphic arguments from the
// captured arguments which we will do later. Otherwise, we have to
// potentially bind polymorphic arguments from the context if it was a
// partially applied argument.
bool hasPolymorphicParams = hasPolymorphicParameters(origType);
if (!layout && hasPolymorphicParams) {
assert(conventions.size() == 1);
// We could have either partially applied an argument from the function
// signature or otherwise we could have a closure context to forward. We only
// care for the former for the purpose of reconstructing polymorphic
// parameters from regular arguments.
if (!calleeHasContext) {
unsigned paramI =
findSinglePartiallyAppliedParameterIndexIgnoringEmptyTypes(
subIGF, substType, outType);
auto paramInfo = substType->getParameters()[paramI];
auto &ti = IGM.getTypeInfoForLowered(paramInfo.getArgumentType(
IGM.getSILModule(), substType, IGM.getMaximalTypeExpansionContext()));
Explosion param;
auto ref = rawData;
// We can get a '{ swift.refcounted* }' type for AnyObject on linux.
if (!ti.getStorageType()->isPointerTy() &&
ti.isSingleSwiftRetainablePointer(ResilienceExpansion::Maximal))
ref = subIGF.coerceValue(rawData, ti.getStorageType(),
subIGF.IGM.DataLayout);
else
ref = subIGF.Builder.CreateBitCast(rawData, ti.getStorageType());
param.add(ref);
bindPolymorphicParameter(subIGF, origType, substType, param, paramI);
(void)param.claimAll();
}
emitPolymorphicArguments(subIGF, origType, subs,
&witnessMetadata, polyArgs);
}
auto haveContextArgument =
calleeHasContext || hasSelfContextParameter(origType);
// Witness method calls expect self, followed by the self type followed by,
// the witness table at the end of the parameter list. But polymorphic
// arguments come before this.
bool isWitnessMethodCallee = origType->getRepresentation() ==
SILFunctionTypeRepresentation::WitnessMethod;
bool isMethodCallee =
origType->getRepresentation() == SILFunctionTypeRepresentation::Method;
Explosion witnessMethodSelfValue;
llvm::Value *lastCapturedFieldPtr = nullptr;
// If there's a data pointer required, but it's a swift-retainable
// value being passed as the context, just forward it down.
if (!layout) {
assert(conventions.size() == 1);
// We need to retain the parameter if:
// - we received at +0 (either) and are passing as owned
// - we received as unowned and are passing as guaranteed
auto argConvention = conventions[nextCapturedField++];
switch (argConvention) {
case ParameterConvention::Indirect_In:
case ParameterConvention::Indirect_In_Constant:
case ParameterConvention::Direct_Owned:
if (!consumesContext) subIGF.emitNativeStrongRetain(rawData, subIGF.getDefaultAtomicity());
break;
case ParameterConvention::Indirect_In_Guaranteed:
case ParameterConvention::Direct_Guaranteed:
dependsOnContextLifetime = true;
if (outType->getCalleeConvention() ==
ParameterConvention::Direct_Unowned) {
subIGF.emitNativeStrongRetain(rawData, subIGF.getDefaultAtomicity());
consumesContext = true;
}
break;
case ParameterConvention::Direct_Unowned:
// Make sure we release later if we received at +1.
if (consumesContext)
dependsOnContextLifetime = true;
break;
case ParameterConvention::Indirect_Inout:
case ParameterConvention::Indirect_InoutAliasable:
llvm_unreachable("should never happen!");
}
// FIXME: The naming and documentation here isn't ideal. This
// parameter is always present which is evident since we always
// grab a type to cast to, but sometimes after the polymorphic
// arguments. This is just following the lead of existing (and not
// terribly easy to follow) code.
// If there is a context argument, it comes after the polymorphic
// arguments.
auto argIndex = emission->getCurrentArgumentIndex();
if (haveContextArgument)
argIndex += polyArgs.size();
llvm::Type *expectedArgTy = origSig.getType()->getParamType(argIndex);
llvm::Value *argValue;
if (isIndirectFormalParameter(argConvention)) {
// We can use rawData's type for the alloca because it is a swift
// retainable value. Defensively, give it that type. We can't use the
// expectedArgType because it might be a generic parameter and therefore
// have opaque storage.
auto RetainableValue = rawData;
if (RetainableValue->getType() != subIGF.IGM.RefCountedPtrTy)
RetainableValue = subIGF.Builder.CreateBitCast(
RetainableValue, subIGF.IGM.RefCountedPtrTy);
needsAllocas = true;
auto temporary = subIGF.createAlloca(RetainableValue->getType(),
subIGF.IGM.getPointerAlignment(),
"partial-apply.context");
subIGF.Builder.CreateStore(RetainableValue, temporary);
argValue = temporary.getAddress();
argValue = subIGF.Builder.CreateBitCast(argValue, expectedArgTy);
} else {
argValue = subIGF.Builder.CreateBitCast(rawData, expectedArgTy);
}
emission->addArgument(argValue);
// If there's a data pointer required, grab it and load out the
// extra, previously-curried parameters.
} else {
unsigned origParamI = outType->getParameters().size();
unsigned extraFieldIndex = 0;
assert(layout->getElements().size() == conventions.size()
&& "conventions don't match context layout");
// Calculate non-fixed field offsets.
HeapNonFixedOffsets offsets(subIGF, *layout);
// Perform the loads.
for (unsigned n = layout->getElements().size();
nextCapturedField < n;
++nextCapturedField) {
auto &fieldLayout = layout->getElement(nextCapturedField);
auto &fieldTy = layout->getElementTypes()[nextCapturedField];
auto fieldConvention = conventions[nextCapturedField];
Address fieldAddr = fieldLayout.project(subIGF, data, offsets);
auto &fieldTI = fieldLayout.getType();
lastCapturedFieldPtr = fieldAddr.getAddress();
Explosion param;
switch (fieldConvention) {
case ParameterConvention::Indirect_In:
case ParameterConvention::Indirect_In_Constant: {
auto initStackCopy = [&addressesToDeallocate, &needsAllocas, &param,
&subIGF](const TypeInfo &fieldTI, SILType fieldTy,
Address fieldAddr) {
// The +1 argument is passed indirectly, so we need to copy into a
// temporary.
needsAllocas = true;
auto stackAddr = fieldTI.allocateStack(subIGF, fieldTy, "arg.temp");
auto addressPointer = stackAddr.getAddress().getAddress();
fieldTI.initializeWithCopy(subIGF, stackAddr.getAddress(), fieldAddr,
fieldTy, false);
param.add(addressPointer);
// Remember to deallocate later.
addressesToDeallocate.push_back(
AddressToDeallocate{fieldTy, fieldTI, stackAddr});
};
if (outType->isNoEscape()) {
// If the closure is [onstack] it only captured the address of the
// value. Load that address from the context.
Explosion addressExplosion;
cast<LoadableTypeInfo>(fieldTI).loadAsCopy(subIGF, fieldAddr,
addressExplosion);
assert(fieldTy.isAddress());
auto newFieldTy = fieldTy.getObjectType();
auto &newFieldTI =
subIGF.getTypeInfoForLowered(newFieldTy.getASTType());
fieldAddr =
newFieldTI.getAddressForPointer(addressExplosion.claimNext());
initStackCopy(newFieldTI, newFieldTy, fieldAddr);
} else {
initStackCopy(fieldTI, fieldTy, fieldAddr);
}
break;
}
case ParameterConvention::Indirect_In_Guaranteed:
if (outType->isNoEscape()) {
cast<LoadableTypeInfo>(fieldTI).loadAsCopy(subIGF, fieldAddr, param);
} else {
// The argument is +0, so we can use the address of the param in
// the context directly.
param.add(fieldAddr.getAddress());
dependsOnContextLifetime = true;
}
break;
case ParameterConvention::Indirect_Inout:
case ParameterConvention::Indirect_InoutAliasable:
// Load the address of the inout parameter.
cast<LoadableTypeInfo>(fieldTI).loadAsCopy(subIGF, fieldAddr, param);
break;
case ParameterConvention::Direct_Guaranteed:
case ParameterConvention::Direct_Unowned:
// If the type is nontrivial, keep the context alive since the field
// depends on the context to not be deallocated.
if (!fieldTI.isPOD(ResilienceExpansion::Maximal))
dependsOnContextLifetime = true;
// Load these parameters directly. We can "take" since the parameter is
// +0. This can happen since the context will keep the parameter alive.
cast<LoadableTypeInfo>(fieldTI).loadAsTake(subIGF, fieldAddr, param);
break;
case ParameterConvention::Direct_Owned:
// Copy the value out at +1.
cast<LoadableTypeInfo>(fieldTI).loadAsCopy(subIGF, fieldAddr, param);
break;
}
// Reemit the capture params as unsubstituted.
// Skip empty parameters.
while (origParamI < origType->getParameters().size()) {
if (!isABIIgnoredParameterWithoutStorage(IGM, subIGF, substType,
origParamI))
break;
++origParamI;
}
if (origParamI < origType->getParameters().size()) {
Explosion origParam;
auto origParamInfo = origType->getParameters()[origParamI];
if (hasPolymorphicParams)
bindPolymorphicParameter(subIGF, origType, substType, param,
origParamI);
emitApplyArgument(subIGF, origType, origParamInfo, substType,
emission->getParameterInfo(origParamI), param,
origParam);
bool isWitnessMethodCalleeSelf = (isWitnessMethodCallee &&
origParamI + 1 == origType->getParameters().size());
Explosion arg;
needsAllocas |= emission->transformArgumentToNative(
origParamInfo, origParam,
isWitnessMethodCalleeSelf ? witnessMethodSelfValue : arg);
if (!isWitnessMethodCalleeSelf) {
emission->addArgument(arg, origParamI);
}
++origParamI;
} else {
switch (extraFieldIndex) {
case 0:
emission->addDynamicFunctionContext(
param, isWitnessMethodCallee
? PartialApplicationForwarderEmission::
DynamicFunctionKind::Witness
: PartialApplicationForwarderEmission::
DynamicFunctionKind::PartialApply);
break;
case 1:
emission->addDynamicFunctionPointer(
param, isWitnessMethodCallee
? PartialApplicationForwarderEmission::
DynamicFunctionKind::Witness
: PartialApplicationForwarderEmission::
DynamicFunctionKind::PartialApply);
break;
default:
llvm_unreachable("unexpected extra field in thick context");
}
++extraFieldIndex;
}
}
// If the parameters can live independent of the context, release it now
// so we can tail call. The safety of this assumes that neither this release
// nor any of the loads can throw.
if (consumesContext && !dependsOnContextLifetime && rawData) {
assert(!outType->isNoEscape() && "Trivial context must not be released");
subIGF.emitNativeStrongRelease(rawData, subIGF.getDefaultAtomicity());
}
// Now that we have bound generic parameters from the captured arguments
// emit the polymorphic arguments.
if (hasPolymorphicParameters(origType)) {
emitPolymorphicArguments(subIGF, origType, subs,
&witnessMetadata, polyArgs);
}
}
// Derive the callee function pointer.
auto fnTy = origSig.getType()->getPointerTo();
FunctionPointer fnPtr = [&]() -> FunctionPointer {
// If we found a function pointer statically, great.
if (staticFnPtr) {
if (staticFnPtr->getPointer(subIGF)->getType() != fnTy) {
auto fnPtr = staticFnPtr->getPointer(subIGF);
fnPtr = subIGF.Builder.CreateBitCast(fnPtr, fnTy);
return FunctionPointer(origType, fnPtr, origSig);
}
return *staticFnPtr;
}
// Otherwise, it was the last thing we added to the layout.
assert(lastCapturedFieldPtr);
auto authInfo = PointerAuthInfo::emit(subIGF,
IGM.getOptions().PointerAuth.PartialApplyCapture,
lastCapturedFieldPtr,
PointerAuthEntity::Special::PartialApplyCapture);
// The dynamic function pointer is packed "last" into the context,
// and we pulled it out as an argument. Just pop it off.
auto fnPtr = emission->getDynamicFunctionPointer(authInfo);
// It comes out of the context as an i8*. Cast to the function type.
fnPtr = subIGF.Builder.CreateBitCast(fnPtr, fnTy);
return FunctionPointer(FunctionPointer::KindTy::Function, fnPtr, authInfo,
origSig);
}();
// Derive the context argument if needed. This is either:
// - the saved context argument, in which case it was the last
// thing we added to the layout other than a possible non-static
// function pointer (which we already popped off of 'args'); or
// - 'self', in which case it was the last formal argument.
// In either case, it's the last thing in 'args'.
llvm::Value *fnContext = nullptr;
if (haveContextArgument)
fnContext = emission->getDynamicFunctionContext();
emission->addPolymorphicArguments(std::move(polyArgs));
// If we have a witness method call, the inner context is the
// witness table. Metadata for Self is derived inside the partial
// application thunk and doesn't need to be stored in the outer
// context.
if (isWitnessMethodCallee) {
assert(fnContext->getType() == IGM.Int8PtrTy);
llvm::Value *wtable = subIGF.Builder.CreateBitCast(
fnContext, IGM.WitnessTablePtrTy);
assert(wtable->getType() == IGM.WitnessTablePtrTy);
witnessMetadata.SelfWitnessTable = wtable;
// Okay, this is where the callee context goes.
} else if (fnContext) {
Explosion explosion;
explosion.add(fnContext);
if (isMethodCallee) {
emission->addSelf(explosion);
} else {
emission->addDynamicFunctionContext(
explosion, isWitnessMethodCallee
? PartialApplicationForwarderEmission::
DynamicFunctionKind::Witness
: PartialApplicationForwarderEmission::
DynamicFunctionKind::PartialApply);
}
// Pass a placeholder for thin function calls.
} else if (origType->hasErrorResult() && !origType->isAsync()) {
emission->addArgument(llvm::UndefValue::get(IGM.RefCountedPtrTy));
}
// Add the witness methods self argument before the error parameter after the
// polymorphic arguments.
if (isWitnessMethodCallee)
emission->addSelf(witnessMethodSelfValue);
// Pass down the error result.
if (origType->hasErrorResult()) {
emission->forwardErrorResult();
}
assert(emission->originalParametersConsumed());
if (isWitnessMethodCallee) {
assert(witnessMetadata.SelfMetadata->getType() == IGM.TypeMetadataPtrTy);
emission->addWitnessSelfMetadata(witnessMetadata.SelfMetadata);
assert(witnessMetadata.SelfWitnessTable->getType() == IGM.WitnessTablePtrTy);
emission->addWitnessSelfWitnessTable(witnessMetadata.SelfWitnessTable);
}
llvm::CallInst *call = emission->createCall(fnPtr);
if (addressesToDeallocate.empty() && !needsAllocas &&
(!consumesContext || !dependsOnContextLifetime))
call->setTailCall();
// Deallocate everything we allocated above.
// FIXME: exceptions?
for (auto &entry : addressesToDeallocate) {
entry.TI.deallocateStack(subIGF, entry.Addr, entry.Type);
}
// If the parameters depended on the context, consume the context now.
if (rawData && consumesContext && dependsOnContextLifetime) {
assert(!outType->isNoEscape() && "Trivial context must not be released");
subIGF.emitNativeStrongRelease(rawData, subIGF.getDefaultAtomicity());
}
emission->createReturn(call);
emission->end();
return fwd;
}
/// Emit a partial application thunk for a function pointer applied to a partial
/// set of argument values.
Optional<StackAddress> irgen::emitFunctionPartialApplication(
IRGenFunction &IGF, SILFunction &SILFn, const FunctionPointer &fn,
llvm::Value *fnContext, Explosion &args, ArrayRef<SILParameterInfo> params,
SubstitutionMap subs, CanSILFunctionType origType,
CanSILFunctionType substType, CanSILFunctionType outType, Explosion &out,
bool isOutlined) {
// If we have a single Swift-refcounted context value, we can adopt it
// directly as our closure context without creating a box and thunk.
enum HasSingleSwiftRefcountedContext { Maybe, Yes, No, Thunkable }
hasSingleSwiftRefcountedContext = Maybe;
Optional<ParameterConvention> singleRefcountedConvention;
SmallVector<const TypeInfo *, 4> argTypeInfos;
SmallVector<SILType, 4> argValTypes;
SmallVector<ParameterConvention, 4> argConventions;
if (origType->isAsync()) {
// Store the size of the partially applied async function's context here so
// that it can be recovered by at the apply site.
auto int32ASTType =
BuiltinIntegerType::get(32, IGF.IGM.IRGen.SIL.getASTContext())
->getCanonicalType();
auto int32SILType = SILType::getPrimitiveObjectType(int32ASTType);
const TypeInfo &int32TI = IGF.IGM.getTypeInfo(int32SILType);
argValTypes.push_back(int32SILType);
argTypeInfos.push_back(&int32TI);
argConventions.push_back(ParameterConvention::Direct_Unowned);
}
// A context's HeapLayout stores all of the partially applied args.
// A HeapLayout is "fixed" if all of its fields have a fixed layout.
// Otherwise the HeapLayout is "non-fixed".
// Only a non-fixed HeapLayout needs TypeMetadata of the non-fixed fields
// during IRGen of the HeapLayout's destructor function.
// We should not consider partially applied args as TypeMetadata sources,
// because they are available only in the caller and the partial application
// forwarder, but not in the destructor function.
// It is safe to consider partially applied args as TypeMetadata sources for
// "fixed" HeapLayout, because they are not accessed during the IRGen of the
// destructor function.
bool considerParameterSources = true;
for (auto param : params) {
SILType argType = IGF.IGM.silConv.getSILType(
param, origType, IGF.IGM.getMaximalTypeExpansionContext());
auto argLoweringTy = getArgumentLoweringType(argType.getASTType(), param,
outType->isNoEscape());
auto &ti = IGF.getTypeInfoForLowered(argLoweringTy);
if (!isa<FixedTypeInfo>(ti)) {
considerParameterSources = false;
break;
}
}
// Reserve space for polymorphic bindings.
auto bindings = NecessaryBindings::forPartialApplyForwarder(
IGF.IGM, origType, subs, considerParameterSources);
if (origType->isAsync()) {
// The size of the async context needs to be available at the apply site.
//
// TODO: In the "single refcounted context" case the async "function
// pointer" (actually a pointer to a
// constant {
// /*context size*/ i32,
// /*relative address of function*/ i32
// }
// rather than a pointer directly to the function) would be able to
// provide the async context size required. At the apply site, it is
// possible to determine whether we're in the "single refcounted
// context" by looking at the metadata of a nonnull context pointer
// and checking whether it is TargetHeapMetadata.
hasSingleSwiftRefcountedContext = No;
}
if (!bindings.empty()) {
hasSingleSwiftRefcountedContext = No;
auto bindingsSize = bindings.getBufferSize(IGF.IGM);
auto &bindingsTI = IGF.IGM.getOpaqueStorageTypeInfo(bindingsSize,
IGF.IGM.getPointerAlignment());
argValTypes.push_back(SILType());
argTypeInfos.push_back(&bindingsTI);
argConventions.push_back(ParameterConvention::Direct_Unowned);
}
// Collect the type infos for the context parameters.
for (auto param : params) {
SILType argType = IGF.IGM.silConv.getSILType(
param, origType, IGF.IGM.getMaximalTypeExpansionContext());
auto argLoweringTy = getArgumentLoweringType(argType.getASTType(), param,
outType->isNoEscape());
auto &ti = IGF.getTypeInfoForLowered(argLoweringTy);
// Empty values don't matter.
auto schema = ti.getSchema();
if (schema.empty() && !param.isFormalIndirect())
continue;
argValTypes.push_back(argType);
argConventions.push_back(param.getConvention());
argTypeInfos.push_back(&ti);
// Update the single-swift-refcounted check, unless we already ruled that
// out.
if (hasSingleSwiftRefcountedContext == No)
continue;
// Adding nonempty values when we already have a single refcounted pointer
// means we don't have a single value anymore.
if (hasSingleSwiftRefcountedContext != Maybe) {
hasSingleSwiftRefcountedContext = No;
continue;
}
if (ti.isSingleSwiftRetainablePointer(ResilienceExpansion::Maximal)) {
hasSingleSwiftRefcountedContext = Yes;
singleRefcountedConvention = param.getConvention();
} else {
hasSingleSwiftRefcountedContext = No;
}
}
// We can't just bitcast if there's an error parameter to forward.
// This is an unfortunate restriction arising from the fact that a
// thin throwing function will have the signature:
// %result (%arg*, %context*, %error*)
// but the output signature needs to be
// %result (%context*, %error*)
//
// 'swifterror' fixes this physically, but there's still a risk of
// miscompiles because the LLVM optimizer may forward arguments
// positionally without considering 'swifterror'.
//
// Note, however, that we will override this decision below if the
// only thing we have to forward is already a context pointer.
// That's fine.
//
// The proper long-term fix is that closure functions should be
// emitted with a convention that takes the closure box as the
// context parameter. When we do that, all of this code will
// disappear.
if (hasSingleSwiftRefcountedContext == Yes &&
origType->hasErrorResult()) {
hasSingleSwiftRefcountedContext = Thunkable;
}
// If the function pointer is a witness method call, include the witness
// table in the context.
if (origType->getRepresentation() ==
SILFunctionTypeRepresentation::WitnessMethod) {
llvm::Value *wtable = fnContext;
assert(wtable->getType() == IGF.IGM.WitnessTablePtrTy);
// TheRawPointerType lowers as i8*, not i8**.
args.add(IGF.Builder.CreateBitCast(wtable, IGF.IGM.Int8PtrTy));
argValTypes.push_back(SILType::getRawPointerType(IGF.IGM.Context));
argTypeInfos.push_back(
&IGF.getTypeInfoForLowered(IGF.IGM.Context.TheRawPointerType));
argConventions.push_back(ParameterConvention::Direct_Unowned);
hasSingleSwiftRefcountedContext = No;
// Otherwise, we might have a reference-counted context pointer.
} else if (fnContext) {
args.add(fnContext);
argValTypes.push_back(SILType::getNativeObjectType(IGF.IGM.Context));
argConventions.push_back(origType->getCalleeConvention());
argTypeInfos.push_back(
&IGF.getTypeInfoForLowered(IGF.IGM.Context.TheNativeObjectType));
// If this is the only context argument we end up with, we can just share
// it.
if (args.size() == 1) {
assert(bindings.empty());
hasSingleSwiftRefcountedContext = Yes;
singleRefcountedConvention = origType->getCalleeConvention();
}
}
auto outAuthInfo = PointerAuthInfo::forFunctionPointer(IGF.IGM, outType);
// If we have a single refcounted pointer context (and no polymorphic args
// to capture), and the dest ownership semantics match the parameter's,
// skip building the box and thunk and just take the pointer as
// context.
// TODO: We can only do this and use swiftself if all our swiftcc emit the
// last parameter that fits into a register as swiftself.
// We should get this optimization back using the @convention(closure) whose
// box argument should just be swift self.
if (/* DISABLES CODE */ (false) &&
!origType->isPolymorphic() &&
hasSingleSwiftRefcountedContext == Yes &&
outType->getCalleeConvention() == *singleRefcountedConvention) {
assert(args.size() == 1);
auto fnPtr = emitPointerAuthResign(IGF, fn, outAuthInfo).getPointer(IGF);
fnPtr = IGF.Builder.CreateBitCast(fnPtr, IGF.IGM.Int8PtrTy);
out.add(fnPtr);
llvm::Value *ctx = args.claimNext();
ctx = IGF.Builder.CreateBitCast(ctx, IGF.IGM.RefCountedPtrTy);
out.add(ctx);
return {};
}
Optional<FunctionPointer> staticFn;
if (fn.isConstant()) staticFn = fn;
// If the function pointer is dynamic, include it in the context.
size_t nonStaticFnIndex = ~size_t(0);
if (!staticFn) {
nonStaticFnIndex = argTypeInfos.size();
argValTypes.push_back(SILType::getRawPointerType(IGF.IGM.Context));
argTypeInfos.push_back(
&IGF.getTypeInfoForLowered(IGF.IGM.Context.TheRawPointerType));
argConventions.push_back(ParameterConvention::Direct_Unowned);
hasSingleSwiftRefcountedContext = No;
}
// If we only need to capture a single Swift-refcounted object, we
// still need to build a thunk, but we don't need to allocate anything.
if ((hasSingleSwiftRefcountedContext == Yes ||
hasSingleSwiftRefcountedContext == Thunkable) &&
*singleRefcountedConvention != ParameterConvention::Indirect_Inout &&
*singleRefcountedConvention !=
ParameterConvention::Indirect_InoutAliasable) {
assert(bindings.empty());
assert(args.size() == 1);
auto origSig = IGF.IGM.getSignature(origType);
llvm::Value *forwarder =
emitPartialApplicationForwarder(IGF.IGM, staticFn, fnContext != nullptr,
origSig, origType, substType,
outType, subs, nullptr, argConventions);
if (origType->isAsync()) {
llvm_unreachable(
"async functions never have a single refcounted context");
} else {
forwarder = emitPointerAuthSign(IGF, forwarder, outAuthInfo);
forwarder = IGF.Builder.CreateBitCast(forwarder, IGF.IGM.Int8PtrTy);
}
out.add(forwarder);
llvm::Value *ctx = args.claimNext();
if (isIndirectFormalParameter(*singleRefcountedConvention))
ctx = IGF.Builder.CreateLoad(ctx, IGF.IGM.getPointerAlignment());
auto expectedClosureTy =
outType->isNoEscape() ? IGF.IGM.OpaquePtrTy : IGF.IGM.RefCountedPtrTy;
// We might get a struct containing a pointer e.g type <{ %AClass* }>
if (ctx->getType() != expectedClosureTy)
ctx = IGF.coerceValue(ctx, expectedClosureTy, IGF.IGM.DataLayout);
out.add(ctx);
if (outType->isNoEscape())
return StackAddress();
return {};
}
// Store the context arguments on the heap/stack.
assert(argValTypes.size() == argTypeInfos.size()
&& argTypeInfos.size() == argConventions.size()
&& "argument info lists out of sync");
HeapLayout layout(IGF.IGM, LayoutStrategy::Optimal, argValTypes, argTypeInfos,
/*typeToFill*/ nullptr, std::move(bindings),
/*bindingsIndex*/ origType->isAsync() ? 1 : 0);
llvm::Value *data;
Optional<StackAddress> stackAddr;
if (args.empty() && layout.isKnownEmpty()) {
if (outType->isNoEscape())
data = llvm::ConstantPointerNull::get(IGF.IGM.OpaquePtrTy);
else
data = IGF.IGM.RefCountedNull;
} else {
// Allocate a new object on the heap or stack.
HeapNonFixedOffsets offsets(IGF, layout);
if (outType->isNoEscape()) {
stackAddr = IGF.emitDynamicAlloca(
IGF.IGM.Int8Ty, layout.isFixedLayout() ? layout.emitSize(IGF.IGM) : offsets.getSize() , Alignment(16));
stackAddr = stackAddr->withAddress(IGF.Builder.CreateBitCast(
stackAddr->getAddress(), IGF.IGM.OpaquePtrTy));
data = stackAddr->getAddress().getAddress();
} else {
auto descriptor = IGF.IGM.getAddrOfCaptureDescriptor(SILFn, origType,
substType, subs,
layout);
data = IGF.emitUnmanagedAlloc(layout, "closure", descriptor, &offsets);
}
Address dataAddr = layout.emitCastTo(IGF, data);
unsigned i = 0;
if (origType->isAsync()) {
auto &fieldLayout = layout.getElement(i);
auto &fieldTI = fieldLayout.getType();
Address fieldAddr = fieldLayout.project(IGF, dataAddr, offsets);
cast<LoadableTypeInfo>(fieldTI).initialize(IGF, args, fieldAddr,
isOutlined);
++i;
}
// Store necessary bindings, if we have them.
if (layout.hasBindings()) {
auto &bindingsLayout = layout.getElement(i);
Address bindingsAddr = bindingsLayout.project(IGF, dataAddr, offsets);
layout.getBindings().save(IGF, bindingsAddr);
++i;
}
// Store the context arguments.
for (unsigned end = layout.getElements().size(); i < end; ++i) {
auto &fieldLayout = layout.getElement(i);
auto &fieldTy = layout.getElementTypes()[i];
Address fieldAddr = fieldLayout.project(IGF, dataAddr, offsets);
// We don't add non-constant function pointers to the explosion above,
// so we need to handle them specially now.
if (i == nonStaticFnIndex) {
llvm::Value *fnPtr;
if (auto &schema = IGF.getOptions().PointerAuth.PartialApplyCapture) {
auto schemaAuthInfo =
PointerAuthInfo::emit(IGF, schema, fieldAddr.getAddress(),
PointerAuthEntity::Special::PartialApplyCapture);
fnPtr =
emitPointerAuthResign(IGF, fn, schemaAuthInfo).getRawPointer();
} else {
fnPtr = fn.getRawPointer();
}
fnPtr = IGF.Builder.CreateBitCast(fnPtr, IGF.IGM.Int8PtrTy);
IGF.Builder.CreateStore(fnPtr, fieldAddr);
continue;
}
switch (argConventions[i]) {
// Take indirect value arguments out of memory.
case ParameterConvention::Indirect_In:
case ParameterConvention::Indirect_In_Constant:
case ParameterConvention::Indirect_In_Guaranteed: {
if (outType->isNoEscape()) {
cast<LoadableTypeInfo>(fieldLayout.getType())
.initialize(IGF, args, fieldAddr, isOutlined);
} else {
auto addr =
fieldLayout.getType().getAddressForPointer(args.claimNext());
fieldLayout.getType().initializeWithTake(IGF, fieldAddr, addr,
fieldTy, isOutlined);
}
break;
}
// Take direct value arguments and inout pointers by value.
case ParameterConvention::Direct_Unowned:
case ParameterConvention::Direct_Owned:
case ParameterConvention::Direct_Guaranteed:
case ParameterConvention::Indirect_Inout:
case ParameterConvention::Indirect_InoutAliasable:
cast<LoadableTypeInfo>(fieldLayout.getType())
.initialize(IGF, args, fieldAddr, isOutlined);
break;
}
}
}
assert(args.empty() && "unused args in partial application?!");
// Create the forwarding stub.
auto origSig = IGF.IGM.getSignature(origType);
llvm::Value *forwarder = emitPartialApplicationForwarder(
IGF.IGM, staticFn, fnContext != nullptr, origSig, origType, substType,
outType, subs, &layout, argConventions);
forwarder = emitPointerAuthSign(IGF, forwarder, outAuthInfo);
forwarder = IGF.Builder.CreateBitCast(forwarder, IGF.IGM.Int8PtrTy);
out.add(forwarder);
out.add(data);
return stackAddr;
}
/// Emit the block copy helper for a block.
static llvm::Function *emitBlockCopyHelper(IRGenModule &IGM,
CanSILBlockStorageType blockTy,
const BlockStorageTypeInfo &blockTL){
// See if we've produced a block copy helper for this type before.
// TODO
// Create the helper.
llvm::Type *args[] = {
blockTL.getStorageType()->getPointerTo(),
blockTL.getStorageType()->getPointerTo(),
};
auto copyTy = llvm::FunctionType::get(IGM.VoidTy, args, /*vararg*/ false);
// TODO: Give these predictable mangled names and shared linkage.
auto func = llvm::Function::Create(copyTy, llvm::GlobalValue::InternalLinkage,
"block_copy_helper",
IGM.getModule());
func->setAttributes(IGM.constructInitialAttributes());
IRGenFunction IGF(IGM, func);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, func);
// Copy the captures from the source to the destination.
Explosion params = IGF.collectParameters();
auto dest = Address(params.claimNext(), blockTL.getFixedAlignment());
auto src = Address(params.claimNext(), blockTL.getFixedAlignment());
auto destCapture = blockTL.projectCapture(IGF, dest);
auto srcCapture = blockTL.projectCapture(IGF, src);
auto &captureTL = IGM.getTypeInfoForLowered(blockTy->getCaptureType());
captureTL.initializeWithCopy(IGF, destCapture, srcCapture,
blockTy->getCaptureAddressType(), false);
IGF.Builder.CreateRetVoid();
return func;
}
/// Emit the block copy helper for a block.
static llvm::Function *emitBlockDisposeHelper(IRGenModule &IGM,
CanSILBlockStorageType blockTy,
const BlockStorageTypeInfo &blockTL){
// See if we've produced a block destroy helper for this type before.
// TODO
// Create the helper.
auto destroyTy = llvm::FunctionType::get(IGM.VoidTy,
blockTL.getStorageType()->getPointerTo(),
/*vararg*/ false);
// TODO: Give these predictable mangled names and shared linkage.
auto func = llvm::Function::Create(destroyTy,
llvm::GlobalValue::InternalLinkage,
"block_destroy_helper",
IGM.getModule());
func->setAttributes(IGM.constructInitialAttributes());
IRGenFunction IGF(IGM, func);
assert(!func->hasFnAttribute(llvm::Attribute::SanitizeThread));
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, func);
// Destroy the captures.
Explosion params = IGF.collectParameters();
auto storage = Address(params.claimNext(), blockTL.getFixedAlignment());
auto capture = blockTL.projectCapture(IGF, storage);
auto &captureTL = IGM.getTypeInfoForLowered(blockTy->getCaptureType());
captureTL.destroy(IGF, capture, blockTy->getCaptureAddressType(),
false /*block storage code path: never outlined*/);
IGF.Builder.CreateRetVoid();
return func;
}
/// Emit the block header into a block storage slot.
void irgen::emitBlockHeader(IRGenFunction &IGF,
Address storage,
CanSILBlockStorageType blockTy,
llvm::Constant *invokeFunction,
CanSILFunctionType invokeTy,
ForeignFunctionInfo foreignInfo) {
auto &storageTL
= IGF.getTypeInfoForLowered(blockTy).as<BlockStorageTypeInfo>();
Address headerAddr = storageTL.projectBlockHeader(IGF, storage);
//
// Initialize the "isa" pointer, which is _NSConcreteStackBlock.
auto NSConcreteStackBlock =
IGF.IGM.getModule()->getOrInsertGlobal("_NSConcreteStackBlock",
IGF.IGM.ObjCClassStructTy);
ApplyIRLinkage(IRLinkage::ExternalImport)
.to(cast<llvm::GlobalVariable>(NSConcreteStackBlock));
//
// Set the flags.
// - HAS_COPY_DISPOSE unless the capture type is POD
uint32_t flags = 0;
auto &captureTL
= IGF.getTypeInfoForLowered(blockTy->getCaptureType());
bool isPOD = captureTL.isPOD(ResilienceExpansion::Maximal);
if (!isPOD)
flags |= 1 << 25;
// - HAS_STRET, if the invoke function is sret
assert(foreignInfo.ClangInfo);
if (foreignInfo.ClangInfo->getReturnInfo().isIndirect())
flags |= 1 << 29;
// - HAS_SIGNATURE
flags |= 1 << 30;
auto flagsVal = llvm::ConstantInt::get(IGF.IGM.Int32Ty, flags);
// Collect the reserved and invoke pointer fields.
auto reserved = llvm::ConstantInt::get(IGF.IGM.Int32Ty, 0);
llvm::Value *invokeVal = llvm::ConstantExpr::getBitCast(invokeFunction,
IGF.IGM.FunctionPtrTy);
// Build the block descriptor.
ConstantInitBuilder builder(IGF.IGM);
auto descriptorFields = builder.beginStruct();
const clang::ASTContext &ASTContext = IGF.IGM.getClangASTContext();
llvm::IntegerType *UnsignedLongTy =
llvm::IntegerType::get(IGF.IGM.getLLVMContext(),
ASTContext.getTypeSize(ASTContext.UnsignedLongTy));
descriptorFields.addInt(UnsignedLongTy, 0);
descriptorFields.addInt(UnsignedLongTy,
storageTL.getFixedSize().getValue());
if (!isPOD) {
// Define the copy and dispose helpers.
descriptorFields.addSignedPointer(
emitBlockCopyHelper(IGF.IGM, blockTy, storageTL),
IGF.getOptions().PointerAuth.BlockHelperFunctionPointers,
PointerAuthEntity::Special::BlockCopyHelper);
descriptorFields.addSignedPointer(
emitBlockDisposeHelper(IGF.IGM, blockTy, storageTL),
IGF.getOptions().PointerAuth.BlockHelperFunctionPointers,
PointerAuthEntity::Special::BlockDisposeHelper);
}
// Build the descriptor signature.
descriptorFields.add(getBlockTypeExtendedEncoding(IGF.IGM, invokeTy));
// Create the descriptor.
auto descriptor =
descriptorFields.finishAndCreateGlobal("block_descriptor",
IGF.IGM.getPointerAlignment(),
/*constant*/ true);
auto descriptorVal = llvm::ConstantExpr::getBitCast(descriptor,
IGF.IGM.Int8PtrTy);
// Store the block header.
auto layout = IGF.IGM.DataLayout.getStructLayout(IGF.IGM.ObjCBlockStructTy);
IGF.Builder.CreateStore(NSConcreteStackBlock,
IGF.Builder.CreateStructGEP(headerAddr, 0, layout));
IGF.Builder.CreateStore(flagsVal,
IGF.Builder.CreateStructGEP(headerAddr, 1, layout));
IGF.Builder.CreateStore(reserved,
IGF.Builder.CreateStructGEP(headerAddr, 2, layout));
auto invokeAddr = IGF.Builder.CreateStructGEP(headerAddr, 3, layout);
if (auto &schema =
IGF.getOptions().PointerAuth.BlockInvocationFunctionPointers) {
auto invokeAuthInfo = PointerAuthInfo::emit(IGF, schema,
invokeAddr.getAddress(),
invokeTy);
invokeVal = emitPointerAuthSign(IGF, invokeVal, invokeAuthInfo);
}
IGF.Builder.CreateStore(invokeVal, invokeAddr);
IGF.Builder.CreateStore(descriptorVal,
IGF.Builder.CreateStructGEP(headerAddr, 4, layout));
}
llvm::Function *IRGenFunction::getOrCreateResumePrjFn() {
auto name = "__swift_async_resume_project_context";
return cast<llvm::Function>(IGM.getOrCreateHelperFunction(
name, IGM.Int8PtrTy, {IGM.Int8PtrTy},
[&](IRGenFunction &IGF) {
auto it = IGF.CurFn->arg_begin();
auto &Builder = IGF.Builder;
auto addr = Builder.CreateBitOrPointerCast(&(*it), IGF.IGM.Int8PtrPtrTy);
Address callerContextAddr(addr, IGF.IGM.getPointerAlignment());
llvm::Value *callerContext = Builder.CreateLoad(callerContextAddr);
if (auto schema = IGF.IGM.getOptions().PointerAuth.AsyncContextParent) {
auto authInfo =
PointerAuthInfo::emit(IGF, schema, addr, PointerAuthEntity());
callerContext = emitPointerAuthAuth(IGF, callerContext, authInfo);
}
Builder.CreateRet(callerContext);
},
false /*isNoInline*/));
}
llvm::Function *
IRGenFunction::createAsyncDispatchFn(const FunctionPointer &fnPtr,
ArrayRef<llvm::Value *> args) {
SmallVector<llvm::Type*, 8> argTys;
for (auto arg : args) {
auto *ty = arg->getType();
argTys.push_back(ty);
}
return createAsyncDispatchFn(fnPtr, argTys);
}
llvm::Function *
IRGenFunction::createAsyncDispatchFn(const FunctionPointer &fnPtr,
ArrayRef<llvm::Type *> argTypes) {
SmallVector<llvm::Type*, 8> argTys;
argTys.push_back(IGM.Int8PtrTy); // Function pointer to be called.
auto originalAuthInfo = fnPtr.getAuthInfo();
if (fnPtr.getAuthInfo()) {
argTys.push_back(IGM.Int64Ty); // Discriminator for the function pointer.
}
for (auto ty : argTypes) {
argTys.push_back(ty);
}
auto calleeFnPtrType = fnPtr.getRawPointer()->getType();
auto *dispatchFnTy =
llvm::FunctionType::get(IGM.VoidTy, argTys, false /*vaargs*/);
llvm::SmallString<40> name;
llvm::raw_svector_ostream(name)
<< "__swift_suspend_dispatch_" << argTypes.size();
llvm::Function *dispatch =
llvm::Function::Create(dispatchFnTy, llvm::Function::InternalLinkage,
llvm::StringRef(name), &IGM.Module);
dispatch->setCallingConv(IGM.DefaultCC);
dispatch->setDoesNotThrow();
IRGenFunction dispatchIGF(IGM, dispatch);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(dispatchIGF, dispatch);
auto &Builder = dispatchIGF.Builder;
auto it = dispatchIGF.CurFn->arg_begin(), end = dispatchIGF.CurFn->arg_end();
llvm::Value *fnPtrArg = &*(it++);
llvm::Value *discriminatorArg = ((bool)originalAuthInfo) ? &*(it++) : nullptr;
SmallVector<llvm::Value *, 8> callArgs;
for (; it != end; ++it) {
callArgs.push_back(&*it);
}
fnPtrArg = Builder.CreateBitOrPointerCast(fnPtrArg, calleeFnPtrType);
PointerAuthInfo newAuthInfo =
((bool)originalAuthInfo)
? PointerAuthInfo(fnPtr.getAuthInfo().getKey(), discriminatorArg)
: originalAuthInfo;
auto callee = FunctionPointer(fnPtr.getKind(), fnPtrArg, newAuthInfo,
fnPtr.getSignature());
auto call = Builder.CreateCall(callee, callArgs);
call->setTailCall();
Builder.CreateRetVoid();
return dispatch;
}
void IRGenFunction::emitSuspensionPoint(llvm::Value *toExecutor,
llvm::Value *asyncResume) {
llvm::Value *task = getAsyncTask();
llvm::Value *callableResume = asyncResume;
if (auto schema = IGM.getOptions().PointerAuth.TaskResumeFunction) {
auto *resumeAddr = Builder.CreateStructGEP(task, 4);
auto authInfo = PointerAuthInfo::emit(
*this, schema, resumeAddr, PointerAuthEntity());
callableResume = emitPointerAuthSign(*this, asyncResume, authInfo);
}
// Setup the suspend point.
SmallVector<llvm::Value *, 8> arguments;
arguments.push_back(asyncResume);
auto resumeProjFn = getOrCreateResumeFromSuspensionFn();
arguments.push_back(
Builder.CreateBitOrPointerCast(resumeProjFn, IGM.Int8PtrTy));
llvm::Function *suspendFn = createAsyncSuspendFn();
arguments.push_back(
Builder.CreateBitOrPointerCast(suspendFn, IGM.Int8PtrTy));
arguments.push_back(callableResume);
arguments.push_back(
Builder.CreateBitOrPointerCast(toExecutor, getAsyncExecutor()->getType()));
arguments.push_back(task);
arguments.push_back(getAsyncExecutor());
arguments.push_back(getAsyncContext());
emitSuspendAsyncCall(arguments);
}
llvm::Function *IRGenFunction::getOrCreateResumeFromSuspensionFn() {
auto name = "__swift_async_resume_get_context";
return cast<llvm::Function>(IGM.getOrCreateHelperFunction(
name, IGM.Int8PtrTy, {IGM.Int8PtrTy},
[&](IRGenFunction &IGF) {
auto &Builder = IGF.Builder;
Builder.CreateRet(&*IGF.CurFn->arg_begin());
},
false /*isNoInline*/));
}
llvm::Function *IRGenFunction::createAsyncSuspendFn() {
SmallVector<llvm::Type*, 8> argTys;
argTys.push_back(IGM.Int8PtrTy); // Resume function.
argTys.push_back(getAsyncExecutor()->getType()); // Executor to hop to.
argTys.push_back(getAsyncTask()->getType());
argTys.push_back(getAsyncExecutor()->getType());
argTys.push_back(getAsyncContext()->getType());
auto *suspendFnTy =
llvm::FunctionType::get(IGM.VoidTy, argTys, false /*vaargs*/);
StringRef name = "__swift_suspend_point";
if (llvm::GlobalValue *F = IGM.Module.getNamedValue(name))
return cast<llvm::Function>(F);
llvm::Function *suspendFn =
llvm::Function::Create(suspendFnTy, llvm::Function::InternalLinkage,
name, &IGM.Module);
suspendFn->setCallingConv(IGM.DefaultCC);
suspendFn->setDoesNotThrow();
IRGenFunction suspendIGF(IGM, suspendFn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(suspendIGF, suspendFn);
auto &Builder = suspendIGF.Builder;
llvm::Value *resumeFunction = suspendFn->getArg(0);
llvm::Value *targetExecutor = suspendFn->getArg(1);
llvm::Value *task = suspendFn->getArg(2);
llvm::Value *executor = suspendFn->getArg(3);
llvm::Value *context = suspendFn->getArg(4);
Alignment ptrAlign = IGM.getPointerAlignment();
auto *resumeAddr = Builder.CreateStructGEP(task, 4);
Builder.CreateStore(resumeFunction, Address(resumeAddr, ptrAlign));
auto *contextAddr = Builder.CreateStructGEP(task, 5);
Builder.CreateStore(context, Address(contextAddr, ptrAlign));
auto *suspendCall = Builder.CreateCall(
IGM.getTaskSwitchFuncFn(),
{ task, executor, targetExecutor });
suspendCall->setDoesNotThrow();
suspendCall->setCallingConv(IGM.SwiftCC);
suspendCall->setTailCall();
Builder.CreateRetVoid();
return suspendFn;
}