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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 - 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 signature lowering
// in Swift. This includes creating the IR type, collecting IR attributes,
// performing calls, and supporting prologue and epilogue emission.
//
//===----------------------------------------------------------------------===//
#include "swift/ABI/MetadataValues.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/ClangModuleLoader.h"
#include "swift/AST/GenericEnvironment.h"
#include "swift/Basic/Assertions.h"
#include "swift/IRGen/Linking.h"
#include "swift/Runtime/Config.h"
#include "swift/SIL/SILModule.h"
#include "swift/SIL/SILType.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/GlobalDecl.h"
#include "clang/AST/RecordLayout.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/CodeGen/CodeGenABITypes.h"
#include "clang/CodeGen/ModuleBuilder.h"
#include "clang/Sema/Sema.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/GlobalPtrAuthInfo.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/Support/Compiler.h"
#include <optional>
#include "CallEmission.h"
#include "ClassTypeInfo.h"
#include "EntryPointArgumentEmission.h"
#include "Explosion.h"
#include "GenCall.h"
#include "GenFunc.h"
#include "GenHeap.h"
#include "GenKeyPath.h"
#include "GenObjC.h"
#include "GenPointerAuth.h"
#include "GenPoly.h"
#include "GenProto.h"
#include "GenType.h"
#include "IRGenFunction.h"
#include "IRGenModule.h"
#include "LoadableTypeInfo.h"
#include "NativeConventionSchema.h"
#include "Signature.h"
#include "StructLayout.h"
using namespace swift;
using namespace irgen;
static Size getYieldOnceCoroutineBufferSize(IRGenModule &IGM) {
return NumWords_YieldOnceBuffer * IGM.getPointerSize();
}
static Alignment getYieldOnceCoroutineBufferAlignment(IRGenModule &IGM) {
return IGM.getPointerAlignment();
}
static Size getYieldManyCoroutineBufferSize(IRGenModule &IGM) {
return NumWords_YieldManyBuffer * IGM.getPointerSize();
}
static Alignment getYieldManyCoroutineBufferAlignment(IRGenModule &IGM) {
return IGM.getPointerAlignment();
}
static Size getCoroutineContextSize(IRGenModule &IGM,
CanSILFunctionType fnType) {
switch (fnType->getCoroutineKind()) {
case SILCoroutineKind::None:
llvm_unreachable("expand a coroutine");
case SILCoroutineKind::YieldOnce:
return getYieldOnceCoroutineBufferSize(IGM);
case SILCoroutineKind::YieldMany:
return getYieldManyCoroutineBufferSize(IGM);
}
llvm_unreachable("bad kind");
}
AsyncContextLayout irgen::getAsyncContextLayout(IRGenModule &IGM,
SILFunction *function) {
SubstitutionMap forwardingSubstitutionMap =
function->getForwardingSubstitutionMap();
CanSILFunctionType originalType = function->getLoweredFunctionType();
CanSILFunctionType substitutedType = originalType->substGenericArgs(
IGM.getSILModule(), forwardingSubstitutionMap,
IGM.getMaximalTypeExpansionContext());
auto layout = getAsyncContextLayout(
IGM, originalType, substitutedType, forwardingSubstitutionMap);
return layout;
}
static Size getAsyncContextHeaderSize(IRGenModule &IGM) {
return 2 * IGM.getPointerSize();
}
AsyncContextLayout irgen::getAsyncContextLayout(
IRGenModule &IGM, CanSILFunctionType originalType,
CanSILFunctionType substitutedType, SubstitutionMap substitutionMap) {
// FIXME: everything about this type is way more complicated than it
// needs to be now that we no longer pass and return things in memory
// in the async context and therefore the layout is totally static.
SmallVector<const TypeInfo *, 4> typeInfos;
SmallVector<SILType, 4> valTypes;
// AsyncContext * __ptrauth_swift_async_context_parent Parent;
{
auto ty = SILType();
auto &ti = IGM.getSwiftContextPtrTypeInfo();
valTypes.push_back(ty);
typeInfos.push_back(&ti);
}
// TaskContinuationFunction * __ptrauth_swift_async_context_resume
// ResumeParent;
{
auto ty = SILType();
auto &ti = IGM.getTaskContinuationFunctionPtrTypeInfo();
valTypes.push_back(ty);
typeInfos.push_back(&ti);
}
return AsyncContextLayout(IGM, LayoutStrategy::Optimal, valTypes, typeInfos,
originalType, substitutedType, substitutionMap);
}
AsyncContextLayout::AsyncContextLayout(
IRGenModule &IGM, LayoutStrategy strategy, ArrayRef<SILType> fieldTypes,
ArrayRef<const TypeInfo *> fieldTypeInfos, CanSILFunctionType originalType,
CanSILFunctionType substitutedType, SubstitutionMap substitutionMap)
: StructLayout(IGM, /*type=*/std::nullopt, LayoutKind::NonHeapObject,
strategy, fieldTypeInfos, /*typeToFill*/ nullptr),
originalType(originalType), substitutedType(substitutedType),
substitutionMap(substitutionMap) {
assert(fieldTypeInfos.size() == fieldTypes.size() &&
"type infos don't match types");
assert(this->isFixedLayout());
assert(this->getSize() == getAsyncContextHeaderSize(IGM));
}
Alignment IRGenModule::getAsyncContextAlignment() const {
return Alignment(MaximumAlignment);
}
std::optional<Size>
FunctionPointerKind::getStaticAsyncContextSize(IRGenModule &IGM) const {
if (!isSpecial())
return std::nullopt;
auto headerSize = getAsyncContextHeaderSize(IGM);
headerSize = headerSize.roundUpToAlignment(IGM.getPointerAlignment());
switch (getSpecialKind()) {
case SpecialKind::TaskFutureWaitThrowing:
case SpecialKind::TaskFutureWait:
case SpecialKind::AsyncLetWait:
case SpecialKind::AsyncLetWaitThrowing:
case SpecialKind::AsyncLetGet:
case SpecialKind::AsyncLetGetThrowing:
case SpecialKind::AsyncLetFinish:
case SpecialKind::TaskGroupWaitNext:
case SpecialKind::TaskGroupWaitAll:
case SpecialKind::DistributedExecuteTarget:
// The current guarantee for all of these functions is the same.
// See TaskFutureWaitAsyncContext.
//
// If you add a new special runtime function, it is highly recommended
// that you make calls to it allocate a little more memory than this!
// These frames being this small is very arguably a mistake.
return headerSize + 3 * IGM.getPointerSize();
case SpecialKind::KeyPathAccessor:
return std::nullopt;
}
llvm_unreachable("covered switch");
}
void IRGenFunction::setupAsync(unsigned asyncContextIndex) {
llvm::Value *c = CurFn->getArg(asyncContextIndex);
asyncContextLocation = createAlloca(c->getType(), IGM.getPointerAlignment());
IRBuilder builder(IGM.getLLVMContext(), IGM.DebugInfo != nullptr);
// Insert the stores after the coro.begin.
builder.SetInsertPoint(getEarliestInsertionPoint()->getParent(),
getEarliestInsertionPoint()->getIterator());
builder.CreateStore(c, asyncContextLocation);
}
llvm::Value *IRGenFunction::getAsyncTask() {
auto call = Builder.CreateCall(IGM.getGetCurrentTaskFunctionPointer(), {});
call->setDoesNotThrow();
call->setCallingConv(IGM.SwiftCC);
return call;
}
llvm::Value *IRGenFunction::getAsyncContext() {
assert(isAsync());
return Builder.CreateLoad(asyncContextLocation);
}
void IRGenFunction::storeCurrentAsyncContext(llvm::Value *context) {
context = Builder.CreateBitCast(context, IGM.SwiftContextPtrTy);
Builder.CreateStore(context, asyncContextLocation);
}
llvm::CallInst *IRGenFunction::emitSuspendAsyncCall(
unsigned asyncContextIndex, llvm::StructType *resultTy,
ArrayRef<llvm::Value *> args, bool restoreCurrentContext) {
auto *id = Builder.CreateIntrinsicCall(llvm::Intrinsic::coro_suspend_async,
{resultTy}, args);
if (restoreCurrentContext) {
llvm::Value *calleeContext =
Builder.CreateExtractValue(id, asyncContextIndex);
calleeContext =
Builder.CreateBitOrPointerCast(calleeContext, IGM.Int8PtrTy);
llvm::Function *projectFn = cast<llvm::Function>(
(cast<llvm::Constant>(args[2])->stripPointerCasts()));
auto *fnTy = projectFn->getFunctionType();
llvm::Value *context =
Builder.CreateCallWithoutDbgLoc(fnTy, projectFn, {calleeContext});
storeCurrentAsyncContext(context);
}
return id;
}
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.getLLVMContext(),
fixedTI->getFixedSize().getValue()));
}
}
static void addIndirectValueParameterAttributes(IRGenModule &IGM,
llvm::AttributeList &attrs,
const TypeInfo &ti,
unsigned argIndex) {
llvm::AttrBuilder b(IGM.getLLVMContext());
// Value parameter pointers can't alias or be captured.
b.addAttribute(llvm::Attribute::NoAlias);
// Bitwise takable value types are guaranteed not to capture
// a pointer into itself.
if (ti.isBitwiseTakable(ResilienceExpansion::Maximal))
b.addAttribute(llvm::Attribute::NoCapture);
// The parameter must reference dereferenceable memory of the type.
addDereferenceableAttributeToBuilder(IGM, b, ti);
attrs = attrs.addParamAttributes(IGM.getLLVMContext(), argIndex, b);
}
static void addPackParameterAttributes(IRGenModule &IGM,
SILType paramSILType,
llvm::AttributeList &attrs,
unsigned argIndex) {
llvm::AttrBuilder b(IGM.getLLVMContext());
// Pack parameter pointers can't alias.
// Note: they are not marked `nocapture` as one
// pack parameter could be a value type (e.g. a C++ type)
// that captures its own pointer in itself.
b.addAttribute(llvm::Attribute::NoAlias);
// TODO: we could mark this dereferenceable when the pack has fixed
// components.
// TODO: add an alignment attribute
// TODO: add a nonnull attribute
attrs = attrs.addParamAttributes(IGM.getLLVMContext(), argIndex, b);
}
static void addInoutParameterAttributes(IRGenModule &IGM, SILType paramSILType,
llvm::AttributeList &attrs,
const TypeInfo &ti, unsigned argIndex,
bool aliasable) {
llvm::AttrBuilder b(IGM.getLLVMContext());
// Thanks to exclusivity checking, it is not possible to alias inouts except
// those that are inout_aliasable.
if (!aliasable && paramSILType.getASTType()->getAnyPointerElementType()) {
// To ward against issues with LLVM's alias analysis, for now, only add the
// attribute if it's a pointer being passed inout.
b.addAttribute(llvm::Attribute::NoAlias);
}
// Bitwise takable value types are guaranteed not to capture
// a pointer into itself.
if (ti.isBitwiseTakable(ResilienceExpansion::Maximal))
b.addAttribute(llvm::Attribute::NoCapture);
// The inout must reference dereferenceable memory of the type.
addDereferenceableAttributeToBuilder(IGM, b, ti);
attrs = attrs.addParamAttributes(IGM.getLLVMContext(), argIndex, b);
}
static llvm::CallingConv::ID getFreestandingConvention(IRGenModule &IGM) {
// TODO: use a custom CC that returns three scalars efficiently
return IGM.SwiftCC;
}
/// Expand the requirements of the given abstract calling convention
/// into a "physical" calling convention.
llvm::CallingConv::ID irgen::expandCallingConv(IRGenModule &IGM,
SILFunctionTypeRepresentation convention,
bool isAsync) {
switch (convention) {
case SILFunctionTypeRepresentation::CFunctionPointer:
case SILFunctionTypeRepresentation::ObjCMethod:
case SILFunctionTypeRepresentation::CXXMethod:
case SILFunctionTypeRepresentation::Block:
return IGM.getOptions().PlatformCCallingConvention;
case SILFunctionTypeRepresentation::Method:
case SILFunctionTypeRepresentation::WitnessMethod:
case SILFunctionTypeRepresentation::Closure:
case SILFunctionTypeRepresentation::Thin:
case SILFunctionTypeRepresentation::Thick:
case SILFunctionTypeRepresentation::KeyPathAccessorGetter:
case SILFunctionTypeRepresentation::KeyPathAccessorSetter:
case SILFunctionTypeRepresentation::KeyPathAccessorEquals:
case SILFunctionTypeRepresentation::KeyPathAccessorHash:
if (isAsync)
return IGM.SwiftAsyncCC;
return getFreestandingConvention(IGM);
}
llvm_unreachable("bad calling convention!");
}
static void addIndirectResultAttributes(IRGenModule &IGM,
llvm::AttributeList &attrs,
unsigned paramIndex, bool allowSRet,
llvm::Type *storageType,
const TypeInfo &typeInfo) {
llvm::AttrBuilder b(IGM.getLLVMContext());
b.addAttribute(llvm::Attribute::NoAlias);
// Bitwise takable value types are guaranteed not to capture
// a pointer into itself.
if (typeInfo.isBitwiseTakable(ResilienceExpansion::Maximal))
b.addAttribute(llvm::Attribute::NoCapture);
if (allowSRet) {
assert(storageType);
b.addStructRetAttr(storageType);
}
attrs = attrs.addParamAttributes(IGM.getLLVMContext(), paramIndex, b);
}
// This function should only be called with directly returnable
// result and error types. Errors can only be returned directly if
// they consists solely of int and ptr values.
CombinedResultAndErrorType irgen::combineResultAndTypedErrorType(
const IRGenModule &IGM, const NativeConventionSchema &resultSchema,
const NativeConventionSchema &errorSchema) {
assert(!resultSchema.requiresIndirect());
assert(!errorSchema.shouldReturnTypedErrorIndirectly());
CombinedResultAndErrorType result;
SmallVector<llvm::Type *, 8> elts;
resultSchema.enumerateComponents(
[&](clang::CharUnits offset, clang::CharUnits end, llvm::Type *type) {
elts.push_back(type);
});
SmallVector<llvm::Type *, 8> errorElts;
errorSchema.enumerateComponents(
[&](clang::CharUnits offset, clang::CharUnits end, llvm::Type *type) {
errorElts.push_back(type);
});
llvm::SmallVector<llvm::Type *, 4> combined;
auto resIt = elts.begin();
auto errorIt = errorElts.begin();
while (resIt < elts.end() && errorIt < errorElts.end()) {
auto *res = *resIt;
if (!res->isIntOrPtrTy()) {
combined.push_back(res);
++resIt;
continue;
}
auto *error = *errorIt;
assert(error->isIntOrPtrTy() &&
"Direct errors must only consist of int or ptr values");
result.errorValueMapping.push_back(combined.size());
if (res->getPrimitiveSizeInBits() >= error->getPrimitiveSizeInBits()) {
combined.push_back(res);
} else {
combined.push_back(error);
}
++resIt;
++errorIt;
}
while (resIt < elts.end()) {
combined.push_back(*resIt);
++resIt;
}
while (errorIt < errorElts.end()) {
result.errorValueMapping.push_back(combined.size());
combined.push_back(*errorIt);
++errorIt;
}
if (combined.empty()) {
result.combinedTy = llvm::Type::getVoidTy(IGM.getLLVMContext());
} else if (combined.size() == 1) {
result.combinedTy = combined[0];
} else {
result.combinedTy =
llvm::StructType::get(IGM.getLLVMContext(), combined, /*packed*/ false);
}
return result;
}
void IRGenModule::addSwiftAsyncContextAttributes(llvm::AttributeList &attrs,
unsigned argIndex) {
llvm::AttrBuilder b(getLLVMContext());
b.addAttribute(llvm::Attribute::SwiftAsync);
attrs = attrs.addParamAttributes(this->getLLVMContext(), argIndex, b);
}
void IRGenModule::addSwiftSelfAttributes(llvm::AttributeList &attrs,
unsigned argIndex) {
llvm::AttrBuilder b(getLLVMContext());
b.addAttribute(llvm::Attribute::SwiftSelf);
attrs = attrs.addParamAttributes(this->getLLVMContext(), argIndex, b);
}
void IRGenModule::addSwiftErrorAttributes(llvm::AttributeList &attrs,
unsigned argIndex) {
llvm::AttrBuilder b(getLLVMContext());
// Don't add the swifterror attribute on ABIs that don't pass it in a register.
// We create a shadow stack location of the swifterror parameter for the
// debugger on such platforms and so we can't mark the parameter with a
// swifterror attribute.
if (ShouldUseSwiftError)
b.addAttribute(llvm::Attribute::SwiftError);
// The error result should not be aliased, captured, or pointed at invalid
// addresses regardless.
b.addAttribute(llvm::Attribute::NoAlias);
b.addAttribute(llvm::Attribute::NoCapture);
b.addDereferenceableAttr(getPointerSize().getValue());
attrs = attrs.addParamAttributes(this->getLLVMContext(), argIndex, b);
}
void irgen::addByvalArgumentAttributes(IRGenModule &IGM,
llvm::AttributeList &attrs,
unsigned argIndex, Alignment align,
llvm::Type *storageType) {
llvm::AttrBuilder b(IGM.getLLVMContext());
b.addByValAttr(storageType);
b.addAttribute(llvm::Attribute::getWithAlignment(
IGM.getLLVMContext(), llvm::Align(align.getValue())));
attrs = attrs.addParamAttributes(IGM.getLLVMContext(), argIndex, b);
}
static llvm::Attribute::AttrKind attrKindForExtending(bool signExtend) {
if (signExtend)
return llvm::Attribute::SExt;
return llvm::Attribute::ZExt;
}
namespace swift {
namespace irgen {
namespace {
class SignatureExpansion {
IRGenModule &IGM;
CanSILFunctionType FnType;
bool forStaticCall = false; // Used for objc_method (direct call or not).
// Indicates this is a c++ constructor call.
const clang::CXXConstructorDecl *cxxCtorDecl = nullptr;
public:
SmallVector<llvm::Type*, 8> ParamIRTypes;
llvm::Type *ResultIRType = nullptr;
llvm::AttributeList Attrs;
ForeignFunctionInfo ForeignInfo;
CoroutineInfo CoroInfo;
bool CanUseSRet = true;
bool CanUseError = true;
bool CanUseSelf = true;
unsigned AsyncContextIdx;
unsigned AsyncResumeFunctionSwiftSelfIdx = 0;
FunctionPointerKind FnKind;
SignatureExpansion(IRGenModule &IGM, CanSILFunctionType fnType,
FunctionPointerKind fnKind, bool forStaticCall = false,
const clang::CXXConstructorDecl *cxxCtorDecl = nullptr)
: IGM(IGM), FnType(fnType), forStaticCall(forStaticCall),
cxxCtorDecl(cxxCtorDecl), FnKind(fnKind) {}
/// Expand the components of the primary entrypoint of the function type.
void expandFunctionType(
SignatureExpansionABIDetails *recordedABIDetails = nullptr);
/// Expand the components of the continuation entrypoint of the
/// function type.
void expandCoroutineContinuationType();
// Expand the components for the async continuation entrypoint of the
// function type (the function to be called on returning).
void expandAsyncReturnType();
// Expand the components for the async suspend call of the function type.
void expandAsyncAwaitType();
// Expand the components for the primary entrypoint of the async function
// type.
void expandAsyncEntryType();
Signature getSignature();
private:
const TypeInfo &expand(SILParameterInfo param);
llvm::Type *addIndirectResult(SILType resultType);
SILFunctionConventions getSILFuncConventions() const {
return SILFunctionConventions(FnType, IGM.getSILModule());
}
unsigned getCurParamIndex() {
return ParamIRTypes.size();
}
bool claimSRet() {
bool result = CanUseSRet;
CanUseSRet = false;
return result;
}
bool claimSelf() {
auto Ret = CanUseSelf;
assert(CanUseSelf && "Multiple self parameters?!");
CanUseSelf = false;
return Ret;
}
bool claimError() {
auto Ret = CanUseError;
assert(CanUseError && "Multiple error parameters?!");
CanUseError = false;
return Ret;
}
/// Add a pointer to the given type as the next parameter.
void addPointerParameter(llvm::Type *storageType) {
ParamIRTypes.push_back(storageType->getPointerTo());
}
void addCoroutineContextParameter();
void addAsyncParameters();
void expandResult(SignatureExpansionABIDetails *recordedABIDetails);
/// Returns the LLVM type pointer and its type info for
/// the direct result of this function. If the result is passed indirectly,
/// a void type is returned instead, with a \c null type info.
std::pair<llvm::Type *, const TypeInfo *> expandDirectResult();
std::pair<llvm::Type *, const TypeInfo *> expandDirectErrorType();
void expandIndirectResults();
void expandParameters(SignatureExpansionABIDetails *recordedABIDetails);
void expandKeyPathAccessorParameters();
void expandExternalSignatureTypes();
void expandCoroutineResult(bool forContinuation);
void expandCoroutineContinuationParameters();
void addIndirectThrowingResult();
llvm::Type *getErrorRegisterType();
};
} // end anonymous namespace
} // end namespace irgen
} // end namespace swift
llvm::Type *SignatureExpansion::addIndirectResult(SILType resultType) {
const TypeInfo &resultTI = IGM.getTypeInfo(resultType);
auto storageTy = resultTI.getStorageType();
addIndirectResultAttributes(IGM, Attrs, ParamIRTypes.size(), claimSRet(),
storageTy, resultTI);
addPointerParameter(storageTy);
return IGM.VoidTy;
}
/// Expand all of the direct and indirect result types.
void SignatureExpansion::expandResult(
SignatureExpansionABIDetails *recordedABIDetails) {
if (FnType->isAsync()) {
// The result will be stored within the SwiftContext that is passed to async
// functions.
ResultIRType = IGM.VoidTy;
return;
}
if (FnType->isCoroutine()) {
// This should be easy enough to support if we need to: use the
// same algorithm but add the direct results to the results as if
// they were unioned in.
return expandCoroutineResult(/*for continuation*/ false);
}
auto fnConv = getSILFuncConventions();
// Disable the use of sret if we have multiple indirect results.
if (fnConv.getNumIndirectSILResults() > 1)
CanUseSRet = false;
// Ensure that no parameters were added before to correctly record their ABI
// details.
assert(ParamIRTypes.empty());
// Expand the direct result.
const TypeInfo *directResultTypeInfo;
std::tie(ResultIRType, directResultTypeInfo) = expandDirectResult();
if (!fnConv.hasIndirectSILErrorResults()) {
llvm::Type *directErrorType;
const TypeInfo *directErrorTypeInfo;
std::tie(directErrorType, directErrorTypeInfo) = expandDirectErrorType();
if ((directResultTypeInfo || ResultIRType->isVoidTy()) &&
directErrorTypeInfo) {
ResultIRType = directErrorType;
directResultTypeInfo = directErrorTypeInfo;
}
}
// Expand the indirect results.
expandIndirectResults();
// Record ABI details if asked.
if (!recordedABIDetails)
return;
if (directResultTypeInfo)
recordedABIDetails->directResult =
SignatureExpansionABIDetails::DirectResult{*directResultTypeInfo};
for (unsigned i = 0; i < ParamIRTypes.size(); ++i) {
bool hasSRet = Attrs.hasParamAttr(i, llvm::Attribute::StructRet);
recordedABIDetails->indirectResults.push_back(
SignatureExpansionABIDetails::IndirectResult{hasSRet});
}
}
void SignatureExpansion::expandIndirectResults() {
auto fnConv = getSILFuncConventions();
// Expand the indirect results.
for (auto indirectResultType :
fnConv.getIndirectSILResultTypes(IGM.getMaximalTypeExpansionContext())) {
auto storageTy = IGM.getStorageType(indirectResultType);
auto useSRet = claimSRet();
// We need to use opaque types or non fixed size storage types because llvm
// does type based analysis based on the type of sret arguments.
const TypeInfo &typeInfo = IGM.getTypeInfo(indirectResultType);
if (useSRet && !isa<FixedTypeInfo>(typeInfo)) {
storageTy = IGM.OpaqueTy;
}
addIndirectResultAttributes(IGM, Attrs, ParamIRTypes.size(), useSRet,
storageTy, typeInfo);
addPointerParameter(storageTy);
}
}
namespace {
class YieldSchema {
SILType YieldTy;
const TypeInfo &YieldTI;
std::optional<NativeConventionSchema> NativeSchema;
bool IsIndirect;
public:
YieldSchema(IRGenModule &IGM, SILFunctionConventions fnConv,
SILYieldInfo yield)
: YieldTy(
fnConv.getSILType(yield, IGM.getMaximalTypeExpansionContext())),
YieldTI(IGM.getTypeInfo(YieldTy)) {
if (isFormalIndirect()) {
IsIndirect = true;
} else {
NativeSchema.emplace(IGM, &YieldTI, /*result*/ true);
IsIndirect = NativeSchema->requiresIndirect();
}
}
SILType getSILType() const {
return YieldTy;
}
const TypeInfo &getTypeInfo() const {
return YieldTI;
}
/// Should the yielded value be yielded as a pointer?
bool isIndirect() const { return IsIndirect; }
/// Is the yielded value formally indirect?
bool isFormalIndirect() const { return YieldTy.isAddress(); }
llvm::PointerType *getIndirectPointerType() const {
assert(isIndirect());
return YieldTI.getStorageType()->getPointerTo();
}
const NativeConventionSchema &getDirectSchema() const {
assert(!isIndirect());
return *NativeSchema;
}
void enumerateDirectComponents(llvm::function_ref<void(llvm::Type*)> fn) {
getDirectSchema().enumerateComponents([&](clang::CharUnits begin,
clang::CharUnits end,
llvm::Type *componentTy) {
fn(componentTy);
});
}
};
}
void SignatureExpansion::expandCoroutineResult(bool forContinuation) {
// The return type may be different for the ramp function vs. the
// continuations.
if (forContinuation) {
switch (FnType->getCoroutineKind()) {
case SILCoroutineKind::None:
llvm_unreachable("should have been filtered out before here");
// Yield-once coroutines may optionaly return a value from the continuation.
case SILCoroutineKind::YieldOnce: {
auto fnConv = getSILFuncConventions();
assert(fnConv.getNumIndirectSILResults() == 0);
// Ensure that no parameters were added before to correctly record their ABI
// details.
assert(ParamIRTypes.empty());
// Expand the direct result.
const TypeInfo *directResultTypeInfo;
std::tie(ResultIRType, directResultTypeInfo) = expandDirectResult();
return;
}
// Yield-many coroutines yield the same types from the continuation
// as they do from the ramp function.
case SILCoroutineKind::YieldMany:
assert(FnType->getNumResults() == 0 &&
"having both normal and yield results is currently unsupported");
break;
}
}
SmallVector<llvm::Type*, 8> components;
// The continuation pointer.
components.push_back(IGM.Int8PtrTy);
auto fnConv = getSILFuncConventions();
for (auto yield : FnType->getYields()) {
YieldSchema schema(IGM, fnConv, yield);
// If the individual value must be yielded indirectly, add a pointer.
if (schema.isIndirect()) {
components.push_back(schema.getIndirectPointerType());
continue;
}
// Otherwise, collect all the component types.
schema.enumerateDirectComponents([&](llvm::Type *type) {
components.push_back(type);
});
}
// Find the maximal sequence of the component types that we can
// convince the ABI to pass directly.
// When counting components, ignore the continuation pointer.
unsigned numDirectComponents = components.size() - 1;
SmallVector<llvm::Type*, 8> overflowTypes;
while (clang::CodeGen::swiftcall::
shouldPassIndirectly(IGM.ClangCodeGen->CGM(), components,
/*asReturnValue*/ true)) {
// If we added a pointer to the end of components, remove it.
if (!overflowTypes.empty()) components.pop_back();
// Remove the last component and add it as an overflow type.
overflowTypes.push_back(components.pop_back_val());
--numDirectComponents;
// Add a pointer to the end of components.
components.push_back(IGM.Int8PtrTy);
}
// We'd better have been able to pass at least two pointers.
assert(components.size() >= 2 || overflowTypes.empty());
CoroInfo.NumDirectYieldComponents = numDirectComponents;
// Replace the pointer type we added to components with the real
// pointer-to-overflow type.
if (!overflowTypes.empty()) {
std::reverse(overflowTypes.begin(), overflowTypes.end());
// TODO: should we use some sort of real layout here instead of
// trusting LLVM's?
CoroInfo.indirectResultsType =
llvm::StructType::get(IGM.getLLVMContext(), overflowTypes);
components.back() = CoroInfo.indirectResultsType->getPointerTo();
}
ResultIRType = components.size() == 1
? components.front()
: llvm::StructType::get(IGM.getLLVMContext(), components);
}
void SignatureExpansion::expandCoroutineContinuationParameters() {
// The coroutine context.
addCoroutineContextParameter();
// Whether this is an unwind resumption.
ParamIRTypes.push_back(IGM.Int1Ty);
}
void SignatureExpansion::addAsyncParameters() {
// using TaskContinuationFunction =
// SWIFT_CC(swift)
// void (SWIFT_ASYNC_CONTEXT AsyncContext *);
AsyncContextIdx = getCurParamIndex();
Attrs = Attrs.addParamAttribute(IGM.getLLVMContext(), AsyncContextIdx,
llvm::Attribute::SwiftAsync);
ParamIRTypes.push_back(IGM.SwiftContextPtrTy);
}
void SignatureExpansion::addCoroutineContextParameter() {
// Flag that the context is dereferenceable and unaliased.
auto contextSize = getCoroutineContextSize(IGM, FnType);
Attrs = Attrs.addDereferenceableParamAttr(IGM.getLLVMContext(),
getCurParamIndex(),
contextSize.getValue());
Attrs = Attrs.addParamAttribute(IGM.getLLVMContext(),
getCurParamIndex(),
llvm::Attribute::NoAlias);
ParamIRTypes.push_back(IGM.Int8PtrTy);
}
NativeConventionSchema::NativeConventionSchema(IRGenModule &IGM,
const TypeInfo *ti,
bool IsResult)
: Lowering(IGM.ClangCodeGen->CGM()) {
if (auto *loadable = dyn_cast<LoadableTypeInfo>(ti)) {
// Lower the type according to the Swift ABI.
loadable->addToAggLowering(IGM, Lowering, Size(0));
Lowering.finish();
// Should we pass indirectly according to the ABI?
RequiresIndirect = Lowering.shouldPassIndirectly(IsResult);
} else {
Lowering.finish();
RequiresIndirect = true;
}
}
llvm::Type *NativeConventionSchema::getExpandedType(IRGenModule &IGM) const {
if (empty())
return IGM.VoidTy;
SmallVector<llvm::Type *, 8> elts;
enumerateComponents([&](clang::CharUnits offset, clang::CharUnits end,
llvm::Type *type) { elts.push_back(type); });
if (elts.size() == 1)
return elts[0];
auto &ctx = IGM.getLLVMContext();
return llvm::StructType::get(ctx, elts, /*packed*/ false);
}
std::pair<llvm::StructType *, llvm::StructType *>
NativeConventionSchema::getCoercionTypes(
IRGenModule &IGM, SmallVectorImpl<unsigned> &expandedTyIndicesMap) const {
auto &ctx = IGM.getLLVMContext();
if (empty()) {
auto type = llvm::StructType::get(ctx);
return {type, type};
}
clang::CharUnits lastEnd = clang::CharUnits::Zero();
llvm::SmallSet<unsigned, 8> overlappedWithSuccessor;
unsigned idx = 0;
// Mark overlapping ranges.
enumerateComponents(
[&](clang::CharUnits offset, clang::CharUnits end, llvm::Type *type) {
if (offset < lastEnd) {
overlappedWithSuccessor.insert(idx);
}
lastEnd = end;
++idx;
});
// Create the coercion struct with only the integer portion of overlapped
// components and non-overlapped components.
idx = 0;
lastEnd = clang::CharUnits::Zero();
SmallVector<llvm::Type *, 8> elts;
bool packed = false;
enumerateComponents(
[&](clang::CharUnits begin, clang::CharUnits end, llvm::Type *type) {
bool overlapped = overlappedWithSuccessor.count(idx) ||
(idx && overlappedWithSuccessor.count(idx - 1));
++idx;
if (overlapped && !isa<llvm::IntegerType>(type)) {
// keep the old lastEnd for padding.
return;
}
// Add padding (which may include padding for overlapped non-integer
// components).
if (begin != lastEnd) {
auto paddingSize = begin - lastEnd;
assert(!paddingSize.isNegative());
auto padding = llvm::ArrayType::get(llvm::Type::getInt8Ty(ctx),
paddingSize.getQuantity());
elts.push_back(padding);
}
if (!packed && !begin.isMultipleOf(clang::CharUnits::fromQuantity(
IGM.DataLayout.getABITypeAlign(type))))
packed = true;
elts.push_back(type);
expandedTyIndicesMap.push_back(idx - 1);
lastEnd = begin + clang::CharUnits::fromQuantity(
IGM.DataLayout.getTypeAllocSize(type));
assert(end <= lastEnd);
});
auto *coercionType = llvm::StructType::get(ctx, elts, packed);
if (overlappedWithSuccessor.empty())
return {coercionType, llvm::StructType::get(ctx)};
// Create the coercion struct with only the non-integer overlapped
// components.
idx = 0;
lastEnd = clang::CharUnits::Zero();
elts.clear();
packed = false;
enumerateComponents(
[&](clang::CharUnits begin, clang::CharUnits end, llvm::Type *type) {
bool overlapped = overlappedWithSuccessor.count(idx) ||
(idx && overlappedWithSuccessor.count(idx - 1));
++idx;
if (!overlapped || (overlapped && isa<llvm::IntegerType>(type))) {
// Ignore and keep the old lastEnd for padding.
return;
}
// Add padding.
if (begin != lastEnd) {
auto paddingSize = begin - lastEnd;
assert(!paddingSize.isNegative());
auto padding = llvm::ArrayType::get(llvm::Type::getInt8Ty(ctx),
paddingSize.getQuantity());
elts.push_back(padding);
}
if (!packed &&
!begin.isMultipleOf(clang::CharUnits::fromQuantity(
IGM.DataLayout.getABITypeAlign(type))))
packed = true;
elts.push_back(type);
expandedTyIndicesMap.push_back(idx - 1);
lastEnd = begin + clang::CharUnits::fromQuantity(
IGM.DataLayout.getTypeAllocSize(type));