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fuchsia / third_party / swift / refs/tags/swift-DEVELOPMENT-SNAPSHOT-2016-08-07-a / . / lib / IRGen / GenCall.cpp
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//===--- GenCall.cpp - Swift IR Generation for Function Calls -------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements IR generation for function signature lowering
// in Swift. This includes creating the IR type, collecting IR attributes,
// performing calls, and supporting prologue and epilogue emission.
//
//===----------------------------------------------------------------------===//
#include "GenCall.h"
#include "Signature.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/RecordLayout.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/CodeGen/CodeGenABITypes.h"
#include "clang/CodeGen/ModuleBuilder.h"
#include "swift/Basic/Fallthrough.h"
#include "swift/AST/ArchetypeBuilder.h"
#include "llvm/IR/CallSite.h"
#include "CallEmission.h"
#include "Explosion.h"
#include "GenObjC.h"
#include "GenPoly.h"
#include "GenProto.h"
#include "GenType.h"
#include "IRGenFunction.h"
#include "IRGenModule.h"
#include "LoadableTypeInfo.h"
using namespace swift;
using namespace irgen;
bool ExplosionSchema::requiresIndirectResult(IRGenModule &IGM) const {
return containsAggregate() ||
size() > IGM.TargetInfo.MaxScalarsForDirectResult;
}
bool ExplosionSchema::requiresIndirectParameter(IRGenModule &IGM) const {
// For now, use the same condition as requiresIndirectSchema. We may want
// to diverge at some point.
return requiresIndirectResult(IGM);
}
llvm::Type *ExplosionSchema::getScalarResultType(IRGenModule &IGM) const {
if (size() == 0) {
return IGM.VoidTy;
} else if (size() == 1) {
return begin()->getScalarType();
} else {
SmallVector<llvm::Type*, 16> elts;
for (auto &elt : *this) elts.push_back(elt.getScalarType());
return llvm::StructType::get(IGM.getLLVMContext(), elts);
}
}
static void addDereferenceableAttributeToBuilder(IRGenModule &IGM,
llvm::AttrBuilder &b,
const TypeInfo &ti) {
// The addresses of empty values are undefined, so we can't safely mark them
// dereferenceable.
if (ti.isKnownEmpty(ResilienceExpansion::Maximal))
return;
// If we know the type to have a fixed nonempty size, then the pointer is
// dereferenceable to at least that size.
// TODO: Would be nice to have a "getMinimumKnownSize" on TypeInfo for
// dynamic-layout aggregates.
if (auto fixedTI = dyn_cast<FixedTypeInfo>(&ti)) {
b.addAttribute(
llvm::Attribute::getWithDereferenceableBytes(IGM.LLVMContext,
fixedTI->getFixedSize().getValue()));
}
}
static void addIndirectValueParameterAttributes(IRGenModule &IGM,
llvm::AttributeSet &attrs,
const TypeInfo &ti,
unsigned argIndex) {
llvm::AttrBuilder b;
// Value parameter pointers can't alias or be captured.
b.addAttribute(llvm::Attribute::NoAlias);
b.addAttribute(llvm::Attribute::NoCapture);
// The parameter must reference dereferenceable memory of the type.
addDereferenceableAttributeToBuilder(IGM, b, ti);
auto resultAttrs = llvm::AttributeSet::get(IGM.LLVMContext, argIndex+1, b);
attrs = attrs.addAttributes(IGM.LLVMContext, argIndex+1, resultAttrs);
}
static void addInoutParameterAttributes(IRGenModule &IGM,
llvm::AttributeSet &attrs,
const TypeInfo &ti,
unsigned argIndex,
bool aliasable) {
llvm::AttrBuilder b;
// Aliasing inouts is unspecified, but we still want aliasing to be memory-
// safe, so we can't mark inouts as noalias at the LLVM level.
// They still can't be captured without doing unsafe stuff, though.
b.addAttribute(llvm::Attribute::NoCapture);
// The inout must reference dereferenceable memory of the type.
addDereferenceableAttributeToBuilder(IGM, b, ti);
auto resultAttrs = llvm::AttributeSet::get(IGM.LLVMContext, argIndex+1, b);
attrs = attrs.addAttributes(IGM.LLVMContext, argIndex+1, resultAttrs);
}
void ExplosionSchema::addToArgTypes(IRGenModule &IGM,
const TypeInfo &TI,
llvm::AttributeSet &Attrs,
SmallVectorImpl<llvm::Type*> &types) const {
// Pass large arguments as indirect value parameters.
if (requiresIndirectParameter(IGM)) {
addIndirectValueParameterAttributes(IGM, Attrs, TI, types.size());
types.push_back(TI.getStorageType()->getPointerTo());
return;
}
for (auto &elt : *this) {
if (elt.isAggregate())
types.push_back(elt.getAggregateType()->getPointerTo());
else
types.push_back(elt.getScalarType());
}
}
static llvm::CallingConv::ID getFreestandingConvention(IRGenModule &IGM) {
// TODO: use a custom CC that returns three scalars efficiently
return llvm::CallingConv::C;
}
/// Expand the requirements of the given abstract calling convention
/// into a "physical" calling convention.
llvm::CallingConv::ID irgen::expandCallingConv(IRGenModule &IGM,
SILFunctionTypeRepresentation convention) {
switch (convention) {
case SILFunctionTypeRepresentation::CFunctionPointer:
case SILFunctionTypeRepresentation::ObjCMethod:
case SILFunctionTypeRepresentation::Block:
return llvm::CallingConv::C;
case SILFunctionTypeRepresentation::Method:
case SILFunctionTypeRepresentation::WitnessMethod:
SWIFT_FALLTHROUGH;
case SILFunctionTypeRepresentation::Thin:
case SILFunctionTypeRepresentation::Thick:
return getFreestandingConvention(IGM);
}
llvm_unreachable("bad calling convention!");
}
static void addIndirectResultAttributes(IRGenModule &IGM,
llvm::AttributeSet &attrs,
unsigned paramIndex,
bool allowSRet) {
static const llvm::Attribute::AttrKind attrKindsWithSRet[] = {
llvm::Attribute::StructRet,
llvm::Attribute::NoAlias,
llvm::Attribute::NoCapture,
};
static const llvm::Attribute::AttrKind attrKindsWithoutSRet[] = {
llvm::Attribute::NoAlias,
llvm::Attribute::NoCapture,
};
auto resultAttrs =
llvm::AttributeSet::get(IGM.LLVMContext, paramIndex + 1,
(allowSRet ? makeArrayRef(attrKindsWithSRet)
: makeArrayRef(attrKindsWithoutSRet)));
attrs = attrs.addAttributes(IGM.LLVMContext, paramIndex + 1, resultAttrs);
}
static void addSwiftSelfAttributes(IRGenModule &IGM,
llvm::AttributeSet &attrs,
unsigned argIndex) {
static const llvm::Attribute::AttrKind attrKinds[] = {
llvm::Attribute::SwiftSelf,
};
auto argAttrs =
llvm::AttributeSet::get(IGM.LLVMContext, argIndex + 1, attrKinds);
attrs = attrs.addAttributes(IGM.LLVMContext, argIndex + 1, argAttrs);
}
static void addSwiftErrorAttributes(IRGenModule &IGM,
llvm::AttributeSet &attrs,
unsigned argIndex) {
static const llvm::Attribute::AttrKind attrKinds[] = {
llvm::Attribute::SwiftError,
};
auto argAttrs =
llvm::AttributeSet::get(IGM.LLVMContext, argIndex + 1, attrKinds);
attrs = attrs.addAttributes(IGM.LLVMContext, argIndex + 1, argAttrs);
}
void irgen::addByvalArgumentAttributes(IRGenModule &IGM,
llvm::AttributeSet &attrs,
unsigned argIndex,
Alignment align) {
llvm::AttrBuilder b;
b.addAttribute(llvm::Attribute::ByVal);
b.addAttribute(llvm::Attribute::getWithAlignment(IGM.LLVMContext,
align.getValue()));
auto resultAttrs = llvm::AttributeSet::get(IGM.LLVMContext, argIndex+1, b);
attrs = attrs.addAttributes(IGM.LLVMContext,
argIndex+1,
resultAttrs);
}
void irgen::addExtendAttribute(IRGenModule &IGM,
llvm::AttributeSet &attrs,
unsigned index, bool signExtend) {
llvm::AttrBuilder b;
if (signExtend)
b.addAttribute(llvm::Attribute::SExt);
else
b.addAttribute(llvm::Attribute::ZExt);
auto resultAttrs = llvm::AttributeSet::get(IGM.LLVMContext, index, b);
attrs = attrs.addAttributes(IGM.LLVMContext, index, resultAttrs);
}
namespace {
class SignatureExpansion {
IRGenModule &IGM;
CanSILFunctionType FnType;
public:
SmallVector<llvm::Type*, 8> ParamIRTypes;
llvm::AttributeSet Attrs;
ForeignFunctionInfo ForeignInfo;
bool CanUseSRet = true;
SignatureExpansion(IRGenModule &IGM, CanSILFunctionType fnType)
: IGM(IGM), FnType(fnType) {}
llvm::Type *expandSignatureTypes();
private:
void expand(SILParameterInfo param);
llvm::Type *addIndirectResult();
unsigned getCurParamIndex() {
return ParamIRTypes.size();
}
bool claimSRet() {
bool result = CanUseSRet;
CanUseSRet = false;
return result;
}
/// Add a pointer to the given type as the next parameter.
void addPointerParameter(llvm::Type *storageType) {
ParamIRTypes.push_back(storageType->getPointerTo());
}
llvm::Type *expandResult();
llvm::Type *expandDirectResult();
void expandParameters();
llvm::Type *expandExternalSignatureTypes();
};
}
llvm::Type *SignatureExpansion::addIndirectResult() {
auto resultType = FnType->getSILResult();
const TypeInfo &resultTI = IGM.getTypeInfo(resultType);
addIndirectResultAttributes(IGM, Attrs, ParamIRTypes.size(), claimSRet());
addPointerParameter(resultTI.getStorageType());
return IGM.VoidTy;
}
/// Expand all of the direct and indirect result types.
llvm::Type *SignatureExpansion::expandResult() {
// Disable the use of sret if we have multiple indirect results.
if (FnType->getNumIndirectResults() > 1)
CanUseSRet = false;
// Expand the direct result.
llvm::Type *resultType = expandDirectResult();
// Expand the indirect results.
for (auto indirectResult : FnType->getIndirectResults()) {
addIndirectResultAttributes(IGM, Attrs, ParamIRTypes.size(), claimSRet());
addPointerParameter(IGM.getStorageType(indirectResult.getSILType()));
}
return resultType;
}
llvm::Type *SignatureExpansion::expandDirectResult() {
// Handle the direct result type, checking for supposedly scalar
// result types that we actually want to return indirectly.
auto resultType = FnType->getSILResult();
// Fast-path the empty tuple type.
if (auto tuple = resultType.getAs<TupleType>())
if (tuple->getNumElements() == 0)
return IGM.VoidTy;
ExplosionSchema schema = IGM.getSchema(resultType);
switch (FnType->getLanguage()) {
case SILFunctionLanguage::C:
llvm_unreachable("Expanding C/ObjC parameters in the wrong place!");
break;
case SILFunctionLanguage::Swift: {
if (schema.requiresIndirectResult(IGM))
return addIndirectResult();
// Disable the use of sret if we have a non-trivial direct result.
if (!schema.empty()) CanUseSRet = false;
return schema.getScalarResultType(IGM);
}
}
}
static const clang::FieldDecl *
getLargestUnionField(const clang::RecordDecl *record,
const clang::ASTContext &ctx) {
const clang::FieldDecl *largestField = nullptr;
clang::CharUnits unionSize = clang::CharUnits::Zero();
for (auto field : record->fields()) {
assert(!field->isBitField());
clang::CharUnits fieldSize = ctx.getTypeSizeInChars(field->getType());
if (unionSize < fieldSize) {
unionSize = fieldSize;
largestField = field;
}
}
assert(largestField && "empty union?");
return largestField;
}
namespace {
/// A CRTP class for working with Clang's ABIArgInfo::Expand
/// argument type expansions.
template <class Impl, class... Args> struct ClangExpand {
IRGenModule &IGM;
const clang::ASTContext &Ctx;
ClangExpand(IRGenModule &IGM) : IGM(IGM), Ctx(IGM.getClangASTContext()) {}
Impl &asImpl() { return *static_cast<Impl*>(this); }
void visit(clang::CanQualType type, Args... args) {
switch (type->getTypeClass()) {
#define TYPE(Class, Base)
#define NON_CANONICAL_TYPE(Class, Base) \
case clang::Type::Class:
#define DEPENDENT_TYPE(Class, Base) \
case clang::Type::Class:
#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) \
case clang::Type::Class:
#include "clang/AST/TypeNodes.def"
llvm_unreachable("canonical or dependent type in ABI lowering");
// These shouldn't occur in expandable struct types.
case clang::Type::IncompleteArray:
case clang::Type::VariableArray:
llvm_unreachable("variable-sized or incomplete array in ABI lowering");
// We should only ever get ObjC pointers, not underlying objects.
case clang::Type::ObjCInterface:
case clang::Type::ObjCObject:
llvm_unreachable("ObjC object type in ABI lowering");
// We should only ever get function pointers.
case clang::Type::FunctionProto:
case clang::Type::FunctionNoProto:
llvm_unreachable("non-pointer function type in ABI lowering");
// We currently never import C++ code, and we should be able to
// kill Expand before we do.
case clang::Type::LValueReference:
case clang::Type::RValueReference:
case clang::Type::MemberPointer:
case clang::Type::Auto:
llvm_unreachable("C++ type in ABI lowering?");
case clang::Type::Pipe:
llvm_unreachable("OpenCL type in ABI lowering?");
case clang::Type::ConstantArray: {
auto array = Ctx.getAsConstantArrayType(type);
auto elt = Ctx.getCanonicalType(array->getElementType());
auto &&context = asImpl().beginArrayElements(elt);
uint64_t n = array->getSize().getZExtValue();
for (uint64_t i = 0; i != n; ++i) {
asImpl().visitArrayElement(elt, i, context, args...);
}
return;
}
case clang::Type::Record: {
auto record = cast<clang::RecordType>(type)->getDecl();
if (record->isUnion()) {
auto largest = getLargestUnionField(record, Ctx);
asImpl().visitUnionField(record, largest, args...);
} else {
auto &&context = asImpl().beginStructFields(record);
for (auto field : record->fields()) {
asImpl().visitStructField(record, field, context, args...);
}
}
return;
}
case clang::Type::Complex: {
auto elt = type.castAs<clang::ComplexType>().getElementType();
asImpl().visitComplexElement(elt, 0, args...);
asImpl().visitComplexElement(elt, 1, args...);
return;
}
// Just handle this types as opaque integers.
case clang::Type::Enum:
case clang::Type::Atomic:
asImpl().visitScalar(convertTypeAsInteger(type), args...);
return;
case clang::Type::Builtin:
asImpl().visitScalar(
convertBuiltinType(type.castAs<clang::BuiltinType>()),
args...);
return;
case clang::Type::Vector:
case clang::Type::ExtVector:
asImpl().visitScalar(
convertVectorType(type.castAs<clang::VectorType>()),
args...);
return;
case clang::Type::Pointer:
case clang::Type::BlockPointer:
case clang::Type::ObjCObjectPointer:
asImpl().visitScalar(IGM.Int8PtrTy, args...);
return;
}
llvm_unreachable("bad type kind");
}
Size getSizeOfType(clang::QualType type) {
auto clangSize = Ctx.getTypeSizeInChars(type);
return Size(clangSize.getQuantity());
}
private:
llvm::Type *convertVectorType(clang::CanQual<clang::VectorType> type) {
auto eltTy =
convertBuiltinType(type->getElementType().castAs<clang::BuiltinType>());
return llvm::VectorType::get(eltTy, type->getNumElements());
}
llvm::Type *convertBuiltinType(clang::CanQual<clang::BuiltinType> type) {
switch (type.getTypePtr()->getKind()) {
#define BUILTIN_TYPE(Id, SingletonId)
#define PLACEHOLDER_TYPE(Id, SingletonId) \
case clang::BuiltinType::Id:
#include "clang/AST/BuiltinTypes.def"
case clang::BuiltinType::Dependent:
llvm_unreachable("placeholder type in ABI lowering");
// We should never see these unadorned.
case clang::BuiltinType::ObjCId:
case clang::BuiltinType::ObjCClass:
case clang::BuiltinType::ObjCSel:
llvm_unreachable("bare Objective-C object type in ABI lowering");
// This should never be the type of an argument or field.
case clang::BuiltinType::Void:
llvm_unreachable("bare void type in ABI lowering");
// We should never see the OpenCL builtin types at all.
case clang::BuiltinType::OCLImage1d:
case clang::BuiltinType::OCLImage1dArray:
case clang::BuiltinType::OCLImage1dBuffer:
case clang::BuiltinType::OCLImage2d:
case clang::BuiltinType::OCLImage2dArray:
case clang::BuiltinType::OCLImage2dDepth:
case clang::BuiltinType::OCLImage2dArrayDepth:
case clang::BuiltinType::OCLImage2dMSAA:
case clang::BuiltinType::OCLImage2dArrayMSAA:
case clang::BuiltinType::OCLImage2dMSAADepth:
case clang::BuiltinType::OCLImage2dArrayMSAADepth:
case clang::BuiltinType::OCLImage3d:
case clang::BuiltinType::OCLSampler:
case clang::BuiltinType::OCLEvent:
case clang::BuiltinType::OCLClkEvent:
case clang::BuiltinType::OCLQueue:
case clang::BuiltinType::OCLNDRange:
case clang::BuiltinType::OCLReserveID:
llvm_unreachable("OpenCL type in ABI lowering");
// Handle all the integer types as opaque values.
#define BUILTIN_TYPE(Id, SingletonId)
#define SIGNED_TYPE(Id, SingletonId) \
case clang::BuiltinType::Id:
#define UNSIGNED_TYPE(Id, SingletonId) \
case clang::BuiltinType::Id:
#include "clang/AST/BuiltinTypes.def"
return convertTypeAsInteger(type);
// Lower all the floating-point values by their semantics.
case clang::BuiltinType::Half:
return convertFloatingType(Ctx.getTargetInfo().getHalfFormat());
case clang::BuiltinType::Float:
return convertFloatingType(Ctx.getTargetInfo().getFloatFormat());
case clang::BuiltinType::Double:
return convertFloatingType(Ctx.getTargetInfo().getDoubleFormat());
case clang::BuiltinType::LongDouble:
return convertFloatingType(Ctx.getTargetInfo().getLongDoubleFormat());
// nullptr_t -> void*
case clang::BuiltinType::NullPtr:
return IGM.Int8PtrTy;
}
llvm_unreachable("bad builtin type");
}
llvm::Type *convertFloatingType(const llvm::fltSemantics &format) {
if (&format == &llvm::APFloat::IEEEhalf)
return llvm::Type::getHalfTy(IGM.getLLVMContext());
if (&format == &llvm::APFloat::IEEEsingle)
return llvm::Type::getFloatTy(IGM.getLLVMContext());
if (&format == &llvm::APFloat::IEEEdouble)
return llvm::Type::getDoubleTy(IGM.getLLVMContext());
if (&format == &llvm::APFloat::IEEEquad)
return llvm::Type::getFP128Ty(IGM.getLLVMContext());
if (&format == &llvm::APFloat::PPCDoubleDouble)
return llvm::Type::getPPC_FP128Ty(IGM.getLLVMContext());
if (&format == &llvm::APFloat::x87DoubleExtended)
return llvm::Type::getX86_FP80Ty(IGM.getLLVMContext());
llvm_unreachable("bad float format");
}
llvm::Type *convertTypeAsInteger(clang::QualType type) {
auto size = getSizeOfType(type);
return llvm::IntegerType::get(IGM.getLLVMContext(),
size.getValueInBits());
}
};
/// A CRTP specialization of ClangExpand which projects down to
/// various aggregate elements of an address.
///
/// Subclasses should only have to define visitScalar.
template <class Impl>
class ClangExpandProjection : public ClangExpand<Impl, Address> {
using super = ClangExpand<Impl, Address>;
using super::asImpl;
using super::IGM;
using super::Ctx;
using super::getSizeOfType;
protected:
IRGenFunction &IGF;
ClangExpandProjection(IRGenFunction &IGF)
: super(IGF.IGM), IGF(IGF) {}
public:
void visit(clang::CanQualType type, Address addr) {
assert(addr.getType() == IGM.Int8PtrTy);
super::visit(type, addr);
}
Size beginArrayElements(clang::CanQualType element) {
return getSizeOfType(element);
}
void visitArrayElement(clang::CanQualType element, unsigned i,
Size elementSize, Address arrayAddr) {
asImpl().visit(element, createGEPAtOffset(arrayAddr, elementSize * i));
}
void visitComplexElement(clang::CanQualType element, unsigned i,
Address complexAddr) {
Address addr = complexAddr;
if (i) { addr = createGEPAtOffset(complexAddr, getSizeOfType(element)); }
asImpl().visit(element, addr);
}
void visitUnionField(const clang::RecordDecl *record,
const clang::FieldDecl *field,
Address structAddr) {
asImpl().visit(Ctx.getCanonicalType(field->getType()), structAddr);
}
const clang::ASTRecordLayout &
beginStructFields(const clang::RecordDecl *record) {
return Ctx.getASTRecordLayout(record);
}
void visitStructField(const clang::RecordDecl *record,
const clang::FieldDecl *field,
const clang::ASTRecordLayout &layout,
Address structAddr) {
auto fieldIndex = field->getFieldIndex();
assert(!field->isBitField());
auto fieldOffset = Size(layout.getFieldOffset(fieldIndex) / 8);
asImpl().visit(Ctx.getCanonicalType(field->getType()),
createGEPAtOffset(structAddr, fieldOffset));
}
private:
Address createGEPAtOffset(Address addr, Size offset) {
if (offset.isZero()) {
return addr;
} else {
return IGF.Builder.CreateConstByteArrayGEP(addr, offset);
}
}
};
/// A class for collecting the types of a Clang ABIArgInfo::Expand
/// argument expansion.
struct ClangExpandTypeCollector : ClangExpand<ClangExpandTypeCollector> {
SmallVectorImpl<llvm::Type*> &Types;
ClangExpandTypeCollector(IRGenModule &IGM,
SmallVectorImpl<llvm::Type*> &types)
: ClangExpand(IGM), Types(types) {}
bool beginArrayElements(clang::CanQualType element) { return true; }
void visitArrayElement(clang::CanQualType element, unsigned i, bool _) {
visit(element);
}
void visitComplexElement(clang::CanQualType element, unsigned i) {
visit(element);
}
void visitUnionField(const clang::RecordDecl *record,
const clang::FieldDecl *field) {
visit(Ctx.getCanonicalType(field->getType()));
}
bool beginStructFields(const clang::RecordDecl *record) { return true; }
void visitStructField(const clang::RecordDecl *record,
const clang::FieldDecl *field,
bool _) {
visit(Ctx.getCanonicalType(field->getType()));
}
void visitScalar(llvm::Type *type) {
Types.push_back(type);
}
};
}
static bool doesClangExpansionMatchSchema(IRGenModule &IGM,
clang::CanQualType type,
const ExplosionSchema &schema) {
assert(!schema.containsAggregate());
SmallVector<llvm::Type *, 4> expansion;
ClangExpandTypeCollector(IGM, expansion).visit(type);
if (expansion.size() != schema.size())
return false;
for (size_t i = 0, e = schema.size(); i != e; ++i) {
if (schema[i].getScalarType() != expansion[i])
return false;
}
return true;
}
/// Expand the result and parameter types to the appropriate LLVM IR
/// types for C and Objective-C signatures.
llvm::Type *SignatureExpansion::expandExternalSignatureTypes() {
assert(FnType->getLanguage() == SILFunctionLanguage::C);
// Convert the SIL result type to a Clang type.
auto clangResultTy = IGM.getClangType(FnType->getCSemanticResult());
// Now convert the parameters to Clang types.
auto params = FnType->getParameters();
SmallVector<clang::CanQualType,4> paramTys;
auto const &clangCtx = IGM.getClangASTContext();
switch (FnType->getRepresentation()) {
case SILFunctionTypeRepresentation::ObjCMethod: {
// ObjC methods take their 'self' argument first, followed by an
// implicit _cmd argument.
auto &self = params.back();
auto clangTy = IGM.getClangType(self);
paramTys.push_back(clangTy);
paramTys.push_back(clangCtx.VoidPtrTy);
params = params.drop_back();
break;
}
case SILFunctionTypeRepresentation::Block:
// Blocks take their context argument first.
paramTys.push_back(clangCtx.VoidPtrTy);
break;
case SILFunctionTypeRepresentation::CFunctionPointer:
// No implicit arguments.
break;
case SILFunctionTypeRepresentation::Thin:
case SILFunctionTypeRepresentation::Thick:
case SILFunctionTypeRepresentation::Method:
case SILFunctionTypeRepresentation::WitnessMethod:
llvm_unreachable("not a C representation");
}
// Given an index within the clang parameters list, what do we need
// to subtract from it to get to the corresponding index within the
// Swift parameters list?
size_t clangToSwiftParamOffset = paramTys.size();
// Convert each parameter to a Clang type.
for (auto param : params) {
auto clangTy = IGM.getClangType(param);
paramTys.push_back(clangTy);
}
// Generate function info for this signature.
auto extInfo = clang::FunctionType::ExtInfo();
auto &FI = clang::CodeGen::arrangeFreeFunctionCall(IGM.ClangCodeGen->CGM(),
clangResultTy, paramTys, extInfo,
clang::CodeGen::RequiredArgs::All);
ForeignInfo.ClangInfo = &FI;
assert(FI.arg_size() == paramTys.size() &&
"Expected one ArgInfo for each parameter type!");
auto &returnInfo = FI.getReturnInfo();
// Does the result need an extension attribute?
if (returnInfo.isExtend()) {
bool signExt = clangResultTy->hasSignedIntegerRepresentation();
assert((signExt || clangResultTy->hasUnsignedIntegerRepresentation()) &&
"Invalid attempt to add extension attribute to argument!");
addExtendAttribute(IGM, Attrs, llvm::AttributeSet::ReturnIndex, signExt);
}
// If we return indirectly, that is the first parameter type.
if (returnInfo.isIndirect()) {
addIndirectResult();
}
size_t firstParamToLowerNormally = 0;
// Use a special IR type for passing block pointers.
if (FnType->getRepresentation() == SILFunctionTypeRepresentation::Block) {
assert(FI.arg_begin()[0].info.isDirect() &&
"block pointer not passed directly?");
ParamIRTypes.push_back(IGM.ObjCBlockPtrTy);
firstParamToLowerNormally = 1;
}
for (auto i : indices(paramTys).slice(firstParamToLowerNormally)) {
auto &AI = FI.arg_begin()[i].info;
// Add a padding argument if required.
if (auto *padType = AI.getPaddingType())
ParamIRTypes.push_back(padType);
switch (AI.getKind()) {
case clang::CodeGen::ABIArgInfo::Extend: {
bool signExt = paramTys[i]->hasSignedIntegerRepresentation();
assert((signExt || paramTys[i]->hasUnsignedIntegerRepresentation()) &&
"Invalid attempt to add extension attribute to argument!");
addExtendAttribute(IGM, Attrs, getCurParamIndex()+1, signExt);
SWIFT_FALLTHROUGH;
}
case clang::CodeGen::ABIArgInfo::Direct: {
switch (FI.getExtParameterInfo(i).getABI()) {
case clang::ParameterABI::Ordinary:
break;
case clang::ParameterABI::SwiftContext:
addSwiftSelfAttributes(IGM, Attrs, getCurParamIndex());
break;
case clang::ParameterABI::SwiftErrorResult:
addSwiftErrorAttributes(IGM, Attrs, getCurParamIndex());
break;
case clang::ParameterABI::SwiftIndirectResult:
addIndirectResultAttributes(IGM, Attrs, getCurParamIndex(),claimSRet());
break;
}
// If the coercion type is a struct, we need to expand it.
auto type = AI.getCoerceToType();
if (auto expandedType = dyn_cast<llvm::StructType>(type)) {
for (size_t j = 0, e = expandedType->getNumElements(); j != e; ++j)
ParamIRTypes.push_back(expandedType->getElementType(j));
} else {
ParamIRTypes.push_back(type);
}
break;
}
case clang::CodeGen::ABIArgInfo::CoerceAndExpand: {
auto types = AI.getCoerceAndExpandTypeSequence();
ParamIRTypes.append(types.begin(), types.end());
break;
}
case clang::CodeGen::ABIArgInfo::Indirect: {
assert(i >= clangToSwiftParamOffset &&
"Unexpected index for indirect byval argument");
auto &param = params[i - clangToSwiftParamOffset];
auto &paramTI = cast<FixedTypeInfo>(IGM.getTypeInfo(param.getSILType()));
if (AI.getIndirectByVal())
addByvalArgumentAttributes(IGM, Attrs, getCurParamIndex(),
paramTI.getFixedAlignment());
addPointerParameter(paramTI.getStorageType());
break;
}
case clang::CodeGen::ABIArgInfo::Expand:
ClangExpandTypeCollector(IGM, ParamIRTypes).visit(paramTys[i]);
break;
case clang::CodeGen::ABIArgInfo::Ignore:
break;
case clang::CodeGen::ABIArgInfo::InAlloca:
llvm_unreachable("Need to handle InAlloca during signature expansion");
}
}
if (returnInfo.isIndirect() || returnInfo.isIgnore())
return IGM.VoidTy;
return returnInfo.getCoerceToType();
}
void SignatureExpansion::expand(SILParameterInfo param) {
auto &ti = IGM.getTypeInfo(param.getSILType());
switch (auto conv = param.getConvention()) {
case ParameterConvention::Indirect_In:
case ParameterConvention::Indirect_In_Guaranteed:
addIndirectValueParameterAttributes(IGM, Attrs, ti, ParamIRTypes.size());
addPointerParameter(IGM.getStorageType(param.getSILType()));
return;
case ParameterConvention::Indirect_Inout:
case ParameterConvention::Indirect_InoutAliasable:
addInoutParameterAttributes(IGM, Attrs, ti, ParamIRTypes.size(),
conv == ParameterConvention::Indirect_InoutAliasable);
addPointerParameter(IGM.getStorageType(param.getSILType()));
return;
case ParameterConvention::Direct_Owned:
case ParameterConvention::Direct_Unowned:
case ParameterConvention::Direct_Guaranteed:
case ParameterConvention::Direct_Deallocating:
switch (FnType->getLanguage()) {
case SILFunctionLanguage::C: {
llvm_unreachable("Unexpected C/ObjC method in parameter expansion!");
return;
}
case SILFunctionLanguage::Swift: {
auto schema = ti.getSchema();
schema.addToArgTypes(IGM, ti, Attrs, ParamIRTypes);
return;
}
}
llvm_unreachable("bad abstract CC");
}
llvm_unreachable("bad parameter convention");
}
/// Should the given self parameter be given the special treatment
/// for self parameters?
///
/// It's important that this only return true for things that are
/// passed as a single pointer.
bool irgen::isSelfContextParameter(SILParameterInfo param) {
// All the indirect conventions pass a single pointer.
if (param.isIndirect()) {
return true;
}
// Direct conventions depends on the type.
CanType type = param.getType();
// Thick or @objc metatypes (but not existential metatypes).
if (auto metatype = dyn_cast<MetatypeType>(type)) {
return metatype->getRepresentation() != MetatypeRepresentation::Thin;
}
// Classes and class-bounded archetypes.
// No need to apply this to existentials.
// The direct check for SubstitutableType works because only
// class-bounded generic types can be passed directly.
if (type->mayHaveSuperclass() || isa<SubstitutableType>(type)) {
return true;
}
return false;
}
/// Expand the abstract parameters of a SIL function type into the
/// physical parameters of an LLVM function type.
void SignatureExpansion::expandParameters() {
assert(FnType->getRepresentation() != SILFunctionTypeRepresentation::Block
&& "block with non-C calling conv?!");
// First, the formal parameters. But 'self' is treated as the
// context if it has pointer representation.
auto params = FnType->getParameters();
bool hasSelfContext = false;
if (FnType->hasSelfParam() &&
isSelfContextParameter(FnType->getSelfParameter())) {
hasSelfContext = true;
params = params.drop_back();
}
for (auto param : params) {
expand(param);
}
// Next, the generic signature.
if (hasPolymorphicParameters(FnType))
expandPolymorphicSignature(IGM, FnType, ParamIRTypes);
// Context is next.
if (hasSelfContext) {
auto curLength = ParamIRTypes.size(); (void) curLength;
// TODO: 'swift_context' IR attribute
expand(FnType->getSelfParameter());
assert(ParamIRTypes.size() == curLength + 1 &&
"adding 'self' added unexpected number of parameters");
} else {
auto needsContext = [=]() -> bool {
switch (FnType->getRepresentation()) {
case SILFunctionType::Representation::Block:
llvm_unreachable("adding block parameter in Swift CC expansion?");
// Always leave space for a context argument if we have an error result.
case SILFunctionType::Representation::CFunctionPointer:
case SILFunctionType::Representation::Method:
case SILFunctionType::Representation::WitnessMethod:
case SILFunctionType::Representation::ObjCMethod:
case SILFunctionType::Representation::Thin:
return FnType->hasErrorResult();
case SILFunctionType::Representation::Thick:
return true;
}
llvm_unreachable("bad representation kind");
};
if (needsContext()) {
// TODO: 'swift_context' IR attribute
ParamIRTypes.push_back(IGM.RefCountedPtrTy);
}
}
// Error results are last. We always pass them as a pointer to the
// formal error type; LLVM will magically turn this into a non-pointer
// if we set the right attribute.
if (FnType->hasErrorResult()) {
// TODO: 'swift_error' IR attribute
llvm::Type *errorType =
IGM.getStorageType(FnType->getErrorResult().getSILType());
ParamIRTypes.push_back(errorType->getPointerTo());
}
// Witness methods have some extra parameter types.
if (FnType->getRepresentation() ==
SILFunctionTypeRepresentation::WitnessMethod) {
expandTrailingWitnessSignature(IGM, FnType, ParamIRTypes);
}
}
/// Expand the result and parameter types of a SIL function into the
/// physical parameter types of an LLVM function and return the result
/// type.
llvm::Type *SignatureExpansion::expandSignatureTypes() {
switch (FnType->getLanguage()) {
case SILFunctionLanguage::Swift: {
llvm::Type *resultType = expandResult();
expandParameters();
return resultType;
}
case SILFunctionLanguage::C:
return expandExternalSignatureTypes();
}
llvm_unreachable("bad abstract calling convention");
}
Signature Signature::get(IRGenModule &IGM, CanSILFunctionType formalType) {
GenericContextScope scope(IGM, formalType->getGenericSignature());
SignatureExpansion expansion(IGM, formalType);
llvm::Type *resultType = expansion.expandSignatureTypes();
// Create the appropriate LLVM type.
llvm::FunctionType *llvmType =
llvm::FunctionType::get(resultType, expansion.ParamIRTypes,
/*variadic*/ false);
assert((expansion.ForeignInfo.ClangInfo != nullptr) ==
(formalType->getLanguage() == SILFunctionLanguage::C) &&
"C function type without C function info");
Signature result;
result.Type = llvmType;
result.Attributes = expansion.Attrs;
result.ForeignInfo = expansion.ForeignInfo;
return result;
}
/// Return this function pointer, bitcasted to an i8*.
llvm::Value *Callee::getOpaqueFunctionPointer(IRGenFunction &IGF) const {
if (FnPtr->getType() == IGF.IGM.Int8PtrTy)
return FnPtr;
return IGF.Builder.CreateBitCast(FnPtr, IGF.IGM.Int8PtrTy);
}
/// Return this data pointer.
llvm::Value *Callee::getDataPointer(IRGenFunction &IGF) const {
if (hasDataPointer()) return DataPtr;
return IGF.IGM.RefCountedNull;
}
void irgen::extractScalarResults(IRGenFunction &IGF, llvm::Type *bodyType,
llvm::Value *call, Explosion &out) {
assert(!bodyType->isVoidTy() && "Unexpected void result type!");
auto *returned = call;
auto *callType = call->getType();
// If the type of the result of the call differs from the type used
// elsewhere in the caller due to ABI type coercion, we need to
// coerce the result back from the ABI type before extracting the
// elements.
if (bodyType != callType)
returned = IGF.coerceValue(returned, bodyType, IGF.IGM.DataLayout);
if (llvm::StructType *structType = dyn_cast<llvm::StructType>(bodyType))
for (unsigned i = 0, e = structType->getNumElements(); i != e; ++i)
out.add(IGF.Builder.CreateExtractValue(returned, i));
else
out.add(returned);
}
/// Emit the unsubstituted result of this call into the given explosion.
/// The unsubstituted result must be naturally returned directly.
void CallEmission::emitToUnmappedExplosion(Explosion &out) {
assert(LastArgWritten == 0 && "emitting unnaturally to explosion");
auto call = emitCallSite();
// Bail out immediately on a void result.
llvm::Value *result = call.getInstruction();
if (result->getType()->isVoidTy()) return;
CanSILFunctionType origFunctionType = getCallee().getOrigFunctionType();
// If the result was returned autoreleased, implicitly insert the reclaim.
// This is only allowed on a single direct result.
auto directResults = origFunctionType->getDirectResults();
if (directResults.size() == 1 &&
directResults[0].getConvention() == ResultConvention::Autoreleased) {
result = emitObjCRetainAutoreleasedReturnValue(IGF, result);
}
// Get the natural IR type in the body of the function that makes
// the call. This may be different than the IR type returned by the
// call itself due to ABI type coercion.
auto resultType = origFunctionType->getSILResult();
auto schema = IGF.IGM.getSchema(resultType);
auto *bodyType = schema.getScalarResultType(IGF.IGM);
// Extract out the scalar results.
extractScalarResults(IGF, bodyType, result, out);
}
/// Emit the unsubstituted result of this call to the given address.
/// The unsubstituted result must be naturally returned indirectly.
void CallEmission::emitToUnmappedMemory(Address result) {
assert(LastArgWritten == 1 && "emitting unnaturally to indirect result");
Args[0] = result.getAddress();
addIndirectResultAttributes(IGF.IGM, Attrs, 0, true);
#ifndef NDEBUG
LastArgWritten = 0; // appease an assert
#endif
emitCallSite();
}
// FIXME: This doesn't belong on IGF.
llvm::CallSite CallEmission::emitInvoke(llvm::CallingConv::ID convention,
llvm::Value *fn,
ArrayRef<llvm::Value*> args,
const llvm::AttributeSet &attrs) {
// TODO: exceptions!
llvm::CallInst *call = IGF.Builder.CreateCall(fn, args);
call->setAttributes(attrs);
call->setCallingConv(convention);
return call;
}
/// The private routine to ultimately emit a call or invoke instruction.
llvm::CallSite CallEmission::emitCallSite() {
assert(LastArgWritten == 0);
assert(!EmittedCall);
EmittedCall = true;
// Determine the calling convention.
// FIXME: collect attributes in the CallEmission.
auto cc = expandCallingConv(IGF.IGM, getCallee().getRepresentation());
// Make the call and clear the arguments array.
auto fnPtr = getCallee().getFunctionPointer();
auto fnPtrTy = cast<llvm::PointerType>(fnPtr->getType());
auto fnTy = cast<llvm::FunctionType>(fnPtrTy->getElementType());
// Coerce argument types for those cases where the IR type required
// by the ABI differs from the type used within the function body.
assert(fnTy->getNumParams() == Args.size());
for (int i = 0, e = fnTy->getNumParams(); i != e; ++i) {
auto *paramTy = fnTy->getParamType(i);
auto *argTy = Args[i]->getType();
if (paramTy != argTy)
Args[i] = IGF.coerceValue(Args[i], paramTy, IGF.IGM.DataLayout);
}
llvm::CallSite call = emitInvoke(cc, fnPtr, Args,
llvm::AttributeSet::get(fnPtr->getContext(),
Attrs));
Args.clear();
// Return.
return call;
}
/// Emit the result of this call to memory.
void CallEmission::emitToMemory(Address addr,
const LoadableTypeInfo &indirectedResultTI) {
assert(LastArgWritten <= 1);
// If the call is naturally to an explosion, emit it that way and
// then initialize the temporary.
if (LastArgWritten == 0) {
Explosion result;
emitToExplosion(result);
indirectedResultTI.initialize(IGF, result, addr);
return;
}
// Okay, we're naturally emitting to memory.
Address origAddr = addr;
auto origFnType = CurCallee.getOrigFunctionType();
auto substFnType = CurCallee.getSubstFunctionType();
// We're never being asked to do anything with *formal*
// indirect results here, just the possibility of a direct-in-SIL
// result that's actually being passed indirectly.
CanType origResultType = origFnType->getSILResult().getSwiftRValueType();
CanType substResultType = substFnType->getSILResult().getSwiftRValueType();
if (origResultType->hasTypeParameter())
origResultType = IGF.IGM.getContextArchetypes()
.substDependentType(origResultType)
->getCanonicalType();
if (origResultType != substResultType) {
auto origTy = IGF.IGM.getStoragePointerTypeForLowered(origResultType);
origAddr = IGF.Builder.CreateBitCast(origAddr, origTy);
}
emitToUnmappedMemory(origAddr);
}
/// Emit the result of this call to an explosion.
void CallEmission::emitToExplosion(Explosion &out) {
assert(LastArgWritten <= 1);
SILType substResultType =
getCallee().getSubstFunctionType()->getSILResult();
auto &substResultTI =
cast<LoadableTypeInfo>(IGF.getTypeInfo(substResultType));
// If the call is naturally to memory, emit it that way and then
// explode that temporary.
if (LastArgWritten == 1) {
ContainedAddress ctemp = substResultTI.allocateStack(IGF, substResultType,
"call.aggresult");
Address temp = ctemp.getAddress();
emitToMemory(temp, substResultTI);
// We can use a take.
substResultTI.loadAsTake(IGF, temp, out);
substResultTI.deallocateStack(IGF, ctemp.getContainer(), substResultType);
return;
}
// Okay, we're naturally emitting to an explosion.
Explosion temp;
emitToUnmappedExplosion(temp);
// We might need to bitcast the results.
ExplosionSchema resultSchema = substResultTI.getSchema();
assert(temp.size() == resultSchema.size());
for (unsigned i = 0, e = temp.size(); i != e; ++i) {
llvm::Type *expectedType = resultSchema.begin()[i].getScalarType();
llvm::Value *value = temp.claimNext();
if (value->getType() != expectedType)
value = IGF.Builder.CreateBitCast(value, expectedType,
value->getName() + ".asSubstituted");
out.add(value);
}
}
CallEmission::CallEmission(CallEmission &&other)
: IGF(other.IGF),
Attrs(other.Attrs),
Args(std::move(other.Args)),
CurCallee(std::move(other.CurCallee)),
LastArgWritten(other.LastArgWritten),
EmittedCall(other.EmittedCall) {
// Prevent other's destructor from asserting.
other.invalidate();
}
CallEmission::~CallEmission() {
assert(LastArgWritten == 0);
assert(EmittedCall);
}
void CallEmission::invalidate() {
LastArgWritten = 0;
EmittedCall = true;
}
/// Set up this emitter afresh from the current callee specs.
void CallEmission::setFromCallee() {
EmittedCall = false;
unsigned numArgs = CurCallee.getLLVMFunctionType()->getNumParams();
// Set up the args array.
assert(Args.empty());
Args.reserve(numArgs);
Args.set_size(numArgs);
LastArgWritten = numArgs;
auto fnType = CurCallee.getOrigFunctionType();
Attrs = Signature::get(IGF.IGM, fnType).getAttributes();
if (fnType->getRepresentation()
== SILFunctionTypeRepresentation::WitnessMethod) {
unsigned n = getTrailingWitnessSignatureLength(IGF.IGM, fnType);
while (n--) {
Args[--LastArgWritten] = nullptr;
}
}
llvm::Value *contextPtr = nullptr;
if (CurCallee.hasDataPointer())
contextPtr = CurCallee.getDataPointer(IGF);
// Add the error result if we have one.
if (fnType->hasErrorResult()) {
// The invariant is that this is always zero-initialized, so we
// don't need to do anything extra here.
Address errorResultSlot =
IGF.getErrorResultSlot(fnType->getErrorResult().getSILType());
// TODO: Add swift_error attribute.
assert(LastArgWritten > 0);
Args[--LastArgWritten] = errorResultSlot.getAddress();
addAttribute(LastArgWritten + 1, llvm::Attribute::NoCapture);
// Fill in the context pointer if necessary.
if (!contextPtr) {
contextPtr = llvm::UndefValue::get(IGF.IGM.RefCountedPtrTy);
}
}
// Add the data pointer if we have one.
// (Note that we're emitting backwards, so this correctly goes
// *before* the error pointer.)
if (contextPtr) {
assert(fnType->getRepresentation() != SILFunctionTypeRepresentation::Block
&& "block function should not claimed to have data pointer");
assert(LastArgWritten > 0);
Args[--LastArgWritten] = contextPtr;
}
}
bool irgen::canCoerceToSchema(IRGenModule &IGM,
ArrayRef<llvm::Type*> expandedTys,
const ExplosionSchema &schema) {
// If the schemas don't even match in number, we have to go
// through memory.
if (expandedTys.size() != schema.size())
return false;
// If there's just one element, we can always coerce as a scalar.
if (expandedTys.size() == 1) return true;
// If there are multiple elements, the pairs of types need to
// match in size for the coercion to work.
for (size_t i = 0, e = expandedTys.size(); i != e; ++i) {
llvm::Type *inputTy = schema[i].getScalarType();
llvm::Type *outputTy = expandedTys[i];
if (inputTy != outputTy &&
IGM.DataLayout.getTypeSizeInBits(inputTy) !=
IGM.DataLayout.getTypeSizeInBits(outputTy))
return false;
}
// Okay, everything is fine.
return true;
}
static llvm::Type *getOutputType(TranslationDirection direction, unsigned index,
const ExplosionSchema &nativeSchema,
ArrayRef<llvm::Type*> expandedForeignTys) {
assert(nativeSchema.size() == expandedForeignTys.size());
return (direction == TranslationDirection::ToForeign
? expandedForeignTys[index]
: nativeSchema[index].getScalarType());
}
static void emitCoerceAndExpand(IRGenFunction &IGF,
Explosion &in, Explosion &out, SILType paramTy,
const LoadableTypeInfo &paramTI,
llvm::StructType *coercionTy,
ArrayRef<llvm::Type*> expandedTys,
TranslationDirection direction) {
// If we can directly coerce the scalar values, avoid going through memory.
auto schema = paramTI.getSchema();
if (canCoerceToSchema(IGF.IGM, expandedTys, schema)) {
for (auto index : indices(expandedTys)) {
llvm::Value *arg = in.claimNext();
assert(arg->getType() ==
getOutputType(reverse(direction), index, schema, expandedTys));
auto outputTy = getOutputType(direction, index, schema, expandedTys);
if (arg->getType() != outputTy)
arg = IGF.coerceValue(arg, outputTy, IGF.IGM.DataLayout);
out.add(arg);
}
return;
}
// Otherwise, materialize to a temporary.
Address temporary =
paramTI.allocateStack(IGF, paramTy, "coerce-and-expand.temp").getAddress();
auto coercionTyLayout = IGF.IGM.DataLayout.getStructLayout(coercionTy);
// Make the alloca at least as aligned as the coercion struct, just
// so that the element accesses we make don't end up under-aligned.
Alignment coercionTyAlignment = Alignment(coercionTyLayout->getAlignment());
auto alloca = cast<llvm::AllocaInst>(temporary.getAddress());
if (alloca->getAlignment() < coercionTyAlignment.getValue()) {
alloca->setAlignment(coercionTyAlignment.getValue());
temporary = Address(temporary.getAddress(), coercionTyAlignment);
}
// If we're translating *to* the foreign expansion, do an ordinary
// initialization from the input explosion.
if (direction == TranslationDirection::ToForeign) {
paramTI.initialize(IGF, in, temporary);
}
Address coercedTemporary =
IGF.Builder.CreateElementBitCast(temporary, coercionTy);
#ifndef NDEBUG
size_t expandedTyIndex = 0;
#endif
for (auto eltIndex : indices(coercionTy->elements())) {
auto eltTy = coercionTy->getElementType(eltIndex);
// Skip padding fields.
if (eltTy->isArrayTy()) continue;
assert(expandedTys[expandedTyIndex++] == eltTy);
// Project down to the field.
Address eltAddr =
IGF.Builder.CreateStructGEP(coercedTemporary, eltIndex, coercionTyLayout);
// If we're translating *to* the foreign expansion, pull the value out
// of the field and add it to the output.
if (direction == TranslationDirection::ToForeign) {
llvm::Value *value = IGF.Builder.CreateLoad(eltAddr);
out.add(value);
// Otherwise, claim the next value from the input and store that
// in the field.
} else {
llvm::Value *value = in.claimNext();
IGF.Builder.CreateStore(value, eltAddr);
}
}
assert(expandedTyIndex == expandedTys.size());
// If we're translating *from* the foreign expansion, do an ordinary
// load into the output explosion.
if (direction == TranslationDirection::ToNative) {
paramTI.loadAsTake(IGF, temporary, out);
}
paramTI.deallocateStack(IGF, temporary, paramTy);
}
static void emitDirectExternalArgument(IRGenFunction &IGF,
SILType argType, llvm::Type *toTy,
Explosion &in, Explosion &out) {
// If we're supposed to pass directly as a struct type, that
// really means expanding out as multiple arguments.
ArrayRef<llvm::Type*> expandedTys;
if (auto expansionTy = dyn_cast<llvm::StructType>(toTy)) {
// Is there any good reason this isn't public API of llvm::StructType?
expandedTys = makeArrayRef(expansionTy->element_begin(),
expansionTy->getNumElements());
} else {
expandedTys = toTy;
}
auto &argTI = cast<LoadableTypeInfo>(IGF.getTypeInfo(argType));
auto inputSchema = argTI.getSchema();
// Check to see if we can pairwise coerce Swift's exploded scalars
// to Clang's expanded elements.
if (canCoerceToSchema(IGF.IGM, expandedTys, inputSchema)) {
for (auto outputTy : expandedTys) {
llvm::Value *arg = in.claimNext();
if (arg->getType() != outputTy)
arg = IGF.coerceValue(arg, outputTy, IGF.IGM.DataLayout);
out.add(arg);
}
return;
}
// Otherwise, we need to coerce through memory.
// Store to a temporary.
Address temporary = argTI.allocateStack(IGF, argType,
"coerced-arg").getAddress();
argTI.initializeFromParams(IGF, in, temporary, argType);
// Bitcast the temporary to the expected type.
Address coercedAddr =
IGF.Builder.CreateBitCast(temporary, toTy->getPointerTo());
// Project out individual elements if necessary.
if (auto expansionTy = dyn_cast<llvm::StructType>(toTy)) {
auto layout = IGF.IGM.DataLayout.getStructLayout(expansionTy);
for (unsigned i = 0, e = expansionTy->getNumElements(); i != e; ++i) {
auto fieldOffset = Size(layout->getElementOffset(i));
auto fieldAddr = IGF.Builder.CreateStructGEP(coercedAddr, i, fieldOffset);
out.add(IGF.Builder.CreateLoad(fieldAddr));
}
// Otherwise, collect the single scalar.
} else {
out.add(IGF.Builder.CreateLoad(coercedAddr));
}
argTI.deallocateStack(IGF, temporary, argType);
}
namespace {
/// Load a clang argument expansion from a buffer.
struct ClangExpandLoadEmitter :
ClangExpandProjection<ClangExpandLoadEmitter> {
Explosion &Out;
ClangExpandLoadEmitter(IRGenFunction &IGF, Explosion &out)
: ClangExpandProjection(IGF), Out(out) {}
void visitScalar(llvm::Type *scalarTy, Address addr) {
addr = IGF.Builder.CreateBitCast(addr, scalarTy->getPointerTo());
auto value = IGF.Builder.CreateLoad(addr);
Out.add(value);
}
};
/// Store a clang argument expansion into a buffer.
struct ClangExpandStoreEmitter :
ClangExpandProjection<ClangExpandStoreEmitter> {
Explosion &In;
ClangExpandStoreEmitter(IRGenFunction &IGF, Explosion &in)
: ClangExpandProjection(IGF), In(in) {}
void visitScalar(llvm::Type *scalarTy, Address addr) {
auto value = In.claimNext();
addr = IGF.Builder.CreateBitCast(addr, scalarTy->getPointerTo());
IGF.Builder.CreateStore(value, addr);
}
};
}
/// Given a Swift value explosion in 'in', produce a Clang expansion
/// (according to ABIArgInfo::Expand) in 'out'.
static void emitClangExpandedArgument(IRGenFunction &IGF,
Explosion &in, Explosion &out,
clang::CanQualType clangType,
SILType swiftType,
const LoadableTypeInfo &swiftTI) {
// If Clang's expansion schema matches Swift's, great.
auto swiftSchema = swiftTI.getSchema();
if (doesClangExpansionMatchSchema(IGF.IGM, clangType, swiftSchema)) {
return in.transferInto(out, swiftSchema.size());
}
// Otherwise, materialize to a temporary.
Address temp = swiftTI.allocateStack(IGF, swiftType,
"clang-expand-arg.temp").getAddress();
swiftTI.initialize(IGF, in, temp);
Address castTemp = IGF.Builder.CreateBitCast(temp, IGF.IGM.Int8PtrTy);
ClangExpandLoadEmitter(IGF, out).visit(clangType, castTemp);
}
/// Given a Clang-expanded (according to ABIArgInfo::Expand) parameter
/// in 'in', produce a Swift value explosion in 'out'.
void irgen::emitClangExpandedParameter(IRGenFunction &IGF,
Explosion &in, Explosion &out,
clang::CanQualType clangType,
SILType swiftType,
const LoadableTypeInfo &swiftTI) {
// If Clang's expansion schema matches Swift's, great.
auto swiftSchema = swiftTI.getSchema();
if (doesClangExpansionMatchSchema(IGF.IGM, clangType, swiftSchema)) {
return in.transferInto(out, swiftSchema.size());
}
// Otherwise, materialize to a temporary.
Address temp = swiftTI.allocateStack(IGF, swiftType,
"clang-expand-param.temp").getAddress();
Address castTemp = IGF.Builder.CreateBitCast(temp, IGF.IGM.Int8PtrTy);
ClangExpandStoreEmitter(IGF, in).visit(clangType, castTemp);
// Then load out.
swiftTI.loadAsTake(IGF, temp, out);
}
static void externalizeArguments(IRGenFunction &IGF, const Callee &callee,
Explosion &in, Explosion &out) {
auto fnType = callee.getOrigFunctionType();
auto params = fnType->getParameters();
assert(callee.getForeignInfo().ClangInfo);
auto &FI = *callee.getForeignInfo().ClangInfo;
// The index of the first "physical" parameter from paramTys/FI that
// corresponds to a logical parameter from params.
unsigned firstParam = 0;
auto claimNextDirect = [&] {
assert(FI.arg_begin()[firstParam].info.isDirect());
assert(!FI.arg_begin()[firstParam].info.getPaddingType());
out.add(in.claimNext());
firstParam++;
};
// Handle the ObjC prefix.
if (callee.getRepresentation() == SILFunctionTypeRepresentation::ObjCMethod) {
// The first two parameters are pointers, and we make some
// simplifying assumptions.
claimNextDirect();
claimNextDirect();
params = params.drop_back();
// Or the block prefix.
} else if (fnType->getRepresentation()
== SILFunctionTypeRepresentation::Block) {
claimNextDirect();
}
for (unsigned i = firstParam, e = FI.arg_size(); i != e; ++i) {
auto clangParamTy = FI.arg_begin()[i].type;
auto &AI = FI.arg_begin()[i].info;
// We don't need to do anything to handle the Swift parameter-ABI
// attributes here because we shouldn't be trying to round-trip
// swiftcall function pointers through SIL as C functions anyway.
assert(FI.getExtParameterInfo(i).getABI() == clang::ParameterABI::Ordinary);
// Add a padding argument if required.
if (auto *padType = AI.getPaddingType())
out.add(llvm::UndefValue::get(padType));
SILType paramType = params[i - firstParam].getSILType();
switch (AI.getKind()) {
case clang::CodeGen::ABIArgInfo::Extend: {
bool signExt = clangParamTy->hasSignedIntegerRepresentation();
assert((signExt || clangParamTy->hasUnsignedIntegerRepresentation()) &&
"Invalid attempt to add extension attribute to argument!");
(void) signExt;
SWIFT_FALLTHROUGH;
}
case clang::CodeGen::ABIArgInfo::Direct: {
auto toTy = AI.getCoerceToType();
// Indirect parameters are bridged as Clang pointer types.
if (params[i - firstParam].isIndirect()) {
assert(paramType.isAddress() && "SIL type is not an address?");
auto addr = in.claimNext();
if (addr->getType() != toTy)
addr = IGF.coerceValue(addr, toTy, IGF.IGM.DataLayout);
out.add(addr);
break;
}
emitDirectExternalArgument(IGF, paramType, toTy, in, out);
break;
}
case clang::CodeGen::ABIArgInfo::Indirect: {
auto &ti = cast<LoadableTypeInfo>(IGF.getTypeInfo(paramType));
Address addr = ti.allocateStack(IGF, paramType,
"indirect-temporary").getAddress();
ti.initialize(IGF, in, addr);
out.add(addr.getAddress());
break;
}
case clang::CodeGen::ABIArgInfo::CoerceAndExpand: {
auto &paramTI = cast<LoadableTypeInfo>(IGF.getTypeInfo(paramType));
emitCoerceAndExpand(IGF, in, out, paramType, paramTI,
AI.getCoerceAndExpandType(),
AI.getCoerceAndExpandTypeSequence(),
TranslationDirection::ToForeign);
break;
}
case clang::CodeGen::ABIArgInfo::Expand:
emitClangExpandedArgument(IGF, in, out, clangParamTy, paramType,
cast<LoadableTypeInfo>(IGF.getTypeInfo(paramType)));
break;
case clang::CodeGen::ABIArgInfo::Ignore:
break;
case clang::CodeGen::ABIArgInfo::InAlloca:
llvm_unreachable("Need to handle InAlloca when externalizing arguments");
break;
}
}
}
bool irgen::addNativeArgument(IRGenFunction &IGF, Explosion &in,
SILParameterInfo origParamInfo, Explosion &out) {
// Addresses consist of a single pointer argument.
if (isIndirectParameter(origParamInfo.getConvention())) {
out.add(in.claimNext());
return false;
}
auto &ti = cast<LoadableTypeInfo>(IGF.getTypeInfo(origParamInfo.getSILType()));
auto schema = ti.getSchema();
if (schema.requiresIndirectParameter(IGF.IGM)) {
// Pass the argument indirectly.
auto buf = IGF.createAlloca(ti.getStorageType(),
ti.getFixedAlignment(), "");
ti.initialize(IGF, in, buf);
out.add(buf.getAddress());
return true;
} else {
// Pass the argument explosion directly.
ti.reexplode(IGF, in, out);
return false;
}
}
/// Emit a direct parameter that was passed under a C-based CC.
static void emitDirectForeignParameter(IRGenFunction &IGF,
Explosion &in,
llvm::Type *coercionTy,
Explosion &out,
SILType paramType,
const LoadableTypeInfo &paramTI) {
// The ABI IR types for the entrypoint might differ from the
// Swift IR types for the body of the function.
ArrayRef<llvm::Type*> expandedTys;
if (auto expansionTy = dyn_cast<llvm::StructType>(coercionTy)) {
expandedTys = makeArrayRef(expansionTy->element_begin(),
expansionTy->getNumElements());
// Fast-path a really common case. This check assumes that either
// the storage type of a type is an llvm::StructType or it has a
// single-element explosion.
} else if (coercionTy == paramTI.getStorageType()) {
out.add(in.claimNext());
return;
} else {
expandedTys = coercionTy;
}
auto outputSchema = paramTI.getSchema();
// Check to see if we can pairwise-coerce Swift's exploded scalars
// to Clang's expanded elements.
if (canCoerceToSchema(IGF.IGM, expandedTys, outputSchema)) {
for (auto &outputElt : outputSchema) {
llvm::Value *param = in.claimNext();
llvm::Type *outputTy = outputElt.getScalarType();
if (param->getType() != outputTy)
param = IGF.coerceValue(param, outputTy, IGF.IGM.DataLayout);
out.add(param);
}
return;
}
// Otherwise, we need to traffic through memory.
// Create a temporary.
Address temporary; Size tempSize;
std::tie(temporary, tempSize) = allocateForCoercion(IGF,
coercionTy,
paramTI.getStorageType(),
"");
IGF.Builder.CreateLifetimeStart(temporary, tempSize);
// Write the input parameters into the temporary:
Address coercedAddr =
IGF.Builder.CreateBitCast(temporary, coercionTy->getPointerTo());
// Break down a struct expansion if necessary.
if (auto expansionTy = dyn_cast<llvm::StructType>(coercionTy)) {
auto layout = IGF.IGM.DataLayout.getStructLayout(expansionTy);
for (unsigned i = 0, e = expansionTy->getNumElements(); i != e; ++i) {
auto fieldOffset = Size(layout->getElementOffset(i));
auto fieldAddr = IGF.Builder.CreateStructGEP(coercedAddr, i, fieldOffset);
IGF.Builder.CreateStore(in.claimNext(), fieldAddr);
}
// Otherwise, store the single scalar.
} else {
IGF.Builder.CreateStore(in.claimNext(), coercedAddr);
}
// Pull out the elements.
temporary = IGF.Builder.CreateBitCast(temporary,
paramTI.getStorageType()->getPointerTo());
paramTI.loadAsTake(IGF, temporary, out);
// Deallocate the temporary.
// `deallocateStack` emits the lifetime.end marker for us.
paramTI.deallocateStack(IGF, temporary, paramType);
}
void irgen::emitForeignParameter(IRGenFunction &IGF, Explosion &params,
ForeignFunctionInfo foreignInfo,
unsigned foreignParamIndex,
SILType paramTy,
const LoadableTypeInfo &paramTI,
Explosion &paramExplosion) {
assert(foreignInfo.ClangInfo);
auto &FI = *foreignInfo.ClangInfo;
auto clangArgTy = FI.arg_begin()[foreignParamIndex].type;
auto AI = FI.arg_begin()[foreignParamIndex].info;
// We don't need to do anything to handle the Swift parameter-ABI
// attributes here because we shouldn't be trying to round-trip
// swiftcall function pointers through SIL as C functions anyway.
assert(FI.getExtParameterInfo(foreignParamIndex).getABI()
== clang::ParameterABI::Ordinary);
// Drop padding arguments.
if (AI.getPaddingType())
params.claimNext();
switch (AI.getKind()) {
case clang::CodeGen::ABIArgInfo::Extend:
case clang::CodeGen::ABIArgInfo::Direct: {
emitDirectForeignParameter(IGF, params, AI.getCoerceToType(),
paramExplosion, paramTy, paramTI);
return;
}
case clang::CodeGen::ABIArgInfo::Indirect: {
Address address = paramTI.getAddressForPointer(params.claimNext());
paramTI.loadAsTake(IGF, address, paramExplosion);
return;
}
case clang::CodeGen::ABIArgInfo::Expand: {
emitClangExpandedParameter(IGF, params, paramExplosion, clangArgTy,
paramTy, paramTI);
return;
}
case clang::CodeGen::ABIArgInfo::CoerceAndExpand: {
auto &paramTI = cast<LoadableTypeInfo>(IGF.getTypeInfo(paramTy));
emitCoerceAndExpand(IGF, params, paramExplosion, paramTy, paramTI,
AI.getCoerceAndExpandType(),
AI.getCoerceAndExpandTypeSequence(),
TranslationDirection::ToNative);
break;
}
case clang::CodeGen::ABIArgInfo::Ignore:
return;
case clang::CodeGen::ABIArgInfo::InAlloca:
llvm_unreachable("Need to handle InAlloca during signature expansion");
}
}
/// Add a new set of arguments to the function.
void CallEmission::setArgs(Explosion &arg, WitnessMetadata *witnessMetadata) {
// Convert arguments to a representation appropriate to the calling
// convention.
Explosion adjustedArg;
switch (getCallee().getRepresentation()) {
case SILFunctionTypeRepresentation::CFunctionPointer:
case SILFunctionTypeRepresentation::ObjCMethod:
case SILFunctionTypeRepresentation::Block: {
externalizeArguments(IGF, getCallee(), arg, adjustedArg);
break;
}
case SILFunctionTypeRepresentation::WitnessMethod:
assert(witnessMetadata);
assert(witnessMetadata->SelfMetadata->getType() ==
IGF.IGM.TypeMetadataPtrTy);
assert(witnessMetadata->SelfWitnessTable->getType() ==
IGF.IGM.WitnessTablePtrTy);
Args.rbegin()[1] = witnessMetadata->SelfMetadata;
Args.rbegin()[0] = witnessMetadata->SelfWitnessTable;
SWIFT_FALLTHROUGH;
case SILFunctionTypeRepresentation::Method:
case SILFunctionTypeRepresentation::Thin:
case SILFunctionTypeRepresentation::Thick: {
auto origCalleeType = getCallee().getOrigFunctionType();
// Pass along the indirect results.
arg.transferInto(adjustedArg, origCalleeType->getNumIndirectResults());
// Check for value arguments that need to be passed indirectly.
// But don't expect to see 'self' if it's been moved to the context
// position.
auto params = origCalleeType->getParameters();
if (origCalleeType->hasSelfParam() &&
isSelfContextParameter(origCalleeType->getSelfParameter())) {
params = params.drop_back();
}
for (auto param : params) {
addNativeArgument(IGF, arg, param, adjustedArg);
}
// Anything else, just pass along.
adjustedArg.add(arg.claimAll());
break;
}
}
// Add the given number of arguments.
assert(LastArgWritten >= adjustedArg.size());
size_t targetIndex = LastArgWritten - adjustedArg.size();
assert(targetIndex <= 1);
LastArgWritten = targetIndex;
auto argIterator = Args.begin() + targetIndex;
for (auto value : adjustedArg.claimAll()) {
*argIterator++ = value;
}
}
void CallEmission::addAttribute(unsigned Index, llvm::Attribute::AttrKind Attr) {
Attrs = Attrs.addAttribute(IGF.IGM.LLVMContext, Index, Attr);
}
/// Initialize an Explosion with the parameters of the current
/// function. All of the objects will be added unmanaged. This is
/// really only useful when writing prologue code.
Explosion IRGenFunction::collectParameters() {
Explosion params;
for (auto i = CurFn->arg_begin(), e = CurFn->arg_end(); i != e; ++i)
params.add(&*i);
return params;
}
/// Fetch the error result slot.
Address IRGenFunction::getErrorResultSlot(SILType errorType) {
if (!ErrorResultSlot) {
auto &errorTI = cast<FixedTypeInfo>(getTypeInfo(errorType));
IRBuilder builder(IGM.getLLVMContext(), IGM.DebugInfo);
builder.SetInsertPoint(AllocaIP->getParent(), AllocaIP->getIterator());
// Create the alloca. We don't use allocateStack because we're
// not allocating this in stack order.
auto addr = builder.CreateAlloca(errorTI.getStorageType(), nullptr,
"swifterror");
addr->setAlignment(errorTI.getFixedAlignment().getValue());
// TODO: add swift_error attribute
// Initialize at the alloca point.
auto nullError = llvm::ConstantPointerNull::get(
cast<llvm::PointerType>(errorTI.getStorageType()));
builder.CreateStore(nullError, addr, errorTI.getFixedAlignment());
ErrorResultSlot = addr;
}
return Address(ErrorResultSlot, IGM.getPointerAlignment());
}
/// Fetch the error result slot received from the caller.
Address IRGenFunction::getCallerErrorResultSlot() {
assert(ErrorResultSlot && "no error result slot!");
assert(isa<llvm::Argument>(ErrorResultSlot) && "error result slot is local!");
return Address(ErrorResultSlot, IGM.getPointerAlignment());
}
// Set the error result slot. This should only be done in the prologue.
void IRGenFunction::setErrorResultSlot(llvm::Value *address) {
assert(!ErrorResultSlot && "already have error result slot!");
assert(isa<llvm::PointerType>(address->getType()));
ErrorResultSlot = address;
}
/// Emit the basic block that 'return' should branch to and insert it into
/// the current function. This creates a second
/// insertion point that most blocks should be inserted before.
void IRGenFunction::emitBBForReturn() {
ReturnBB = createBasicBlock("return");
CurFn->getBasicBlockList().push_back(ReturnBB);
}
/// Emit the prologue for the function.
void IRGenFunction::emitPrologue() {
// Set up the IRBuilder.
llvm::BasicBlock *EntryBB = createBasicBlock("entry");
assert(CurFn->getBasicBlockList().empty() && "prologue already emitted?");
CurFn->getBasicBlockList().push_back(EntryBB);
Builder.SetInsertPoint(EntryBB);
// Set up the alloca insertion point.
AllocaIP = Builder.CreateAlloca(IGM.Int1Ty, /*array size*/ nullptr,
"alloca point");
}
/// Emit a branch to the return block and set the insert point there.
/// Returns true if the return block is reachable, false otherwise.
bool IRGenFunction::emitBranchToReturnBB() {
// If there are no edges to the return block, we never want to emit it.
if (ReturnBB->use_empty()) {
ReturnBB->eraseFromParent();
// Normally this means that we'll just insert the epilogue in the
// current block, but if the current IP is unreachable then so is
// the entire epilogue.
if (!Builder.hasValidIP())
return false;
// Otherwise, branch to it if the current IP is reachable.
} else if (Builder.hasValidIP()) {
Builder.CreateBr(ReturnBB);
Builder.SetInsertPoint(ReturnBB);
// Otherwise, if there is exactly one use of the return block, merge
// it into its predecessor.
} else if (ReturnBB->hasOneUse()) {
// return statements are never emitted as conditional branches.
llvm::BranchInst *Br = cast<llvm::BranchInst>(*ReturnBB->use_begin());
assert(Br->isUnconditional());
Builder.SetInsertPoint(Br->getParent());
Br->eraseFromParent();
ReturnBB->eraseFromParent();
// Otherwise, just move the IP to the return block.
} else {
Builder.SetInsertPoint(ReturnBB);
}
return true;
}
/// Emit the epilogue for the function.
void IRGenFunction::emitEpilogue() {
// Destroy the alloca insertion point.
AllocaIP->eraseFromParent();
}
std::pair<Address, Size>
irgen::allocateForCoercion(IRGenFunction &IGF,
llvm::Type *fromTy,
llvm::Type *toTy,
const llvm::Twine &basename) {
auto &DL = IGF.IGM.DataLayout;
auto fromSize = DL.getTypeSizeInBits(fromTy);
auto toSize = DL.getTypeSizeInBits(toTy);
auto bufferTy = fromSize >= toSize
? fromTy
: toTy;
auto alignment = std::max(DL.getABITypeAlignment(fromTy),
DL.getABITypeAlignment(toTy));
auto buffer = IGF.createAlloca(bufferTy, Alignment(alignment),
basename + ".coerced");
Size size(std::max(fromSize, toSize));
return {buffer, size};
}
llvm::Value* IRGenFunction::coerceValue(llvm::Value *value, llvm::Type *toTy,
const llvm::DataLayout &DL)
{
llvm::Type *fromTy = value->getType();
assert(fromTy != toTy && "Unexpected same types in type coercion!");
assert(!fromTy->isVoidTy()
&& "Unexpected void source type in type coercion!");
assert(!toTy->isVoidTy()
&& "Unexpected void destination type in type coercion!");
// Use the pointer/pointer and pointer/int casts if we can.
if (toTy->isPointerTy()) {
if (fromTy->isPointerTy())
return Builder.CreateBitCast(value, toTy);
if (fromTy == IGM.IntPtrTy)
return Builder.CreateIntToPtr(value, toTy);
} else if (fromTy->isPointerTy()) {
if (toTy == IGM.IntPtrTy) {
return Builder.CreatePtrToInt(value, toTy);
}
}
// Otherwise we need to store, bitcast, and load.
Address address; Size size;
std::tie(address, size) = allocateForCoercion(*this, fromTy, toTy,
value->getName() + ".coercion");
Builder.CreateLifetimeStart(address, size);
auto orig = Builder.CreateBitCast(address, fromTy->getPointerTo());
Builder.CreateStore(value, orig);
auto coerced = Builder.CreateBitCast(address, toTy->getPointerTo());
auto loaded = Builder.CreateLoad(coerced);
Builder.CreateLifetimeEnd(address, size);
return loaded;
}
void IRGenFunction::emitScalarReturn(llvm::Type *resultType,
Explosion &result) {
if (result.size() == 0) {
Builder.CreateRetVoid();
return;
}
auto *ABIType = CurFn->getReturnType();
if (result.size() == 1) {
auto *returned = result.claimNext();
if (ABIType != returned->getType())
returned = coerceValue(returned, ABIType, IGM.DataLayout);
Builder.CreateRet(returned);
return;
}
// Multiple return values are returned as a struct.
assert(cast<llvm::StructType>(resultType)->getNumElements() == result.size());
llvm::Value *resultAgg = llvm::UndefValue::get(resultType);
for (unsigned i = 0, e = result.size(); i != e; ++i) {
llvm::Value *elt = result.claimNext();
resultAgg = Builder.CreateInsertValue(resultAgg, elt, i);
}
if (ABIType != resultType)
resultAgg = coerceValue(resultAgg, ABIType, IGM.DataLayout);
Builder.CreateRet(resultAgg);
}
void IRGenFunction::emitScalarReturn(SILType resultType, Explosion &result) {
if (result.size() == 0) {
Builder.CreateRetVoid();
return;
}
auto *ABIType = CurFn->getReturnType();
if (result.size() == 1) {
auto *returned = result.claimNext();
if (ABIType != returned->getType())
returned = coerceValue(returned, ABIType, IGM.DataLayout);
Builder.CreateRet(returned);
return;
}
auto &resultTI = IGM.getTypeInfo(resultType);
auto schema = resultTI.getSchema();
auto *bodyType = schema.getScalarResultType(IGM);
// Multiple return values are returned as a struct.
assert(cast<llvm::StructType>(bodyType)->getNumElements() == result.size());
llvm::Value *resultAgg = llvm::UndefValue::get(bodyType);
for (unsigned i = 0, e = result.size(); i != e; ++i) {
llvm::Value *elt = result.claimNext();
resultAgg = Builder.CreateInsertValue(resultAgg, elt, i);
}
if (ABIType != bodyType)
resultAgg = coerceValue(resultAgg, ABIType, IGM.DataLayout);
Builder.CreateRet(resultAgg);
}