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//===--- GenKeyPath.cpp - IRGen support for key path objects --------------===//
//
// 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 contains code for emitting key path patterns, which can be used
// by the standard library to instantiate key path objects.
//
//===----------------------------------------------------------------------===//
#include "Callee.h"
#include "ConstantBuilder.h"
#include "Explosion.h"
#include "GenClass.h"
#include "GenDecl.h"
#include "GenMeta.h"
#include "GenProto.h"
#include "GenStruct.h"
#include "GenType.h"
#include "GenericRequirement.h"
#include "IRGenDebugInfo.h"
#include "IRGenFunction.h"
#include "IRGenModule.h"
#include "MetadataLayout.h"
#include "ProtocolInfo.h"
#include "StructLayout.h"
#include "TypeInfo.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/IR/Module.h"
#include "swift/SIL/SILInstruction.h"
#include "swift/SIL/SILLocation.h"
#include "swift/SIL/TypeLowering.h"
#include "swift/ABI/KeyPath.h"
#include "swift/ABI/HeapObject.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/Decl.h"
#include "swift/AST/DiagnosticEngine.h"
#include "swift/AST/DiagnosticsIRGen.h"
#include "swift/AST/GenericEnvironment.h"
#include "swift/AST/ParameterList.h"
#include "swift/AST/Types.h"
#include "swift/IRGen/Linking.h"
using namespace swift;
using namespace irgen;
enum KeyPathAccessor {
Getter,
Setter,
Equals,
Hash,
};
static void
bindPolymorphicArgumentsFromComponentIndices(IRGenFunction &IGF,
const KeyPathPatternComponent &component,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements,
llvm::Value *args,
llvm::Value *size,
bool hasSubscriptIndices) {
if (!genericEnv)
return;
// The generic environment is marshaled into the end of the component
// argument area inside the instance. Bind the generic information out of
// the buffer.
if (hasSubscriptIndices) {
auto genericArgsSize = llvm::ConstantInt::get(IGF.IGM.SizeTy,
requirements.size() * IGF.IGM.getPointerSize().getValue());
auto genericArgsOffset = IGF.Builder.CreateSub(size, genericArgsSize);
args = IGF.Builder.CreateInBoundsGEP(args, genericArgsOffset);
}
bindFromGenericRequirementsBuffer(IGF, requirements,
Address(args, IGF.IGM.getPointerAlignment()),
MetadataState::Complete,
[&](CanType t) {
return genericEnv->mapTypeIntoContext(t)->getCanonicalType();
});
}
static llvm::Function *
getAccessorForComputedComponent(IRGenModule &IGM,
const KeyPathPatternComponent &component,
KeyPathAccessor whichAccessor,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements,
bool hasSubscriptIndices) {
SILFunction *accessor;
switch (whichAccessor) {
case Getter:
accessor = component.getComputedPropertyGetter();
break;
case Setter:
accessor = component.getComputedPropertySetter();
break;
case Equals:
accessor = component.getSubscriptIndexEquals();
break;
case Hash:
accessor = component.getSubscriptIndexHash();
break;
}
auto accessorFn = IGM.getAddrOfSILFunction(accessor, NotForDefinition);
// If the accessor is not generic, we can use it as is.
if (requirements.empty()) {
return accessorFn;
}
auto accessorFnTy = cast<llvm::FunctionType>(
accessorFn->getType()->getPointerElementType());;
// Otherwise, we need a thunk to unmarshal the generic environment from the
// argument area. It'd be nice to have a good way to represent this
// directly in SIL, of course...
const char *thunkName;
unsigned numArgsToForward;
switch (whichAccessor) {
case Getter:
thunkName = "keypath_get";
numArgsToForward = 2;
break;
case Setter:
thunkName = "keypath_set";
numArgsToForward = 2;
break;
case Equals:
thunkName = "keypath_equals";
numArgsToForward = 2;
break;
case Hash:
thunkName = "keypath_hash";
numArgsToForward = 1;
break;
}
SmallVector<llvm::Type *, 4> thunkParams;
for (unsigned i = 0; i < numArgsToForward; ++i)
thunkParams.push_back(accessorFnTy->getParamType(i));
switch (whichAccessor) {
case Getter:
case Setter:
thunkParams.push_back(IGM.Int8PtrTy);
break;
case Equals:
case Hash:
break;
}
thunkParams.push_back(IGM.SizeTy);
auto thunkType = llvm::FunctionType::get(accessorFnTy->getReturnType(),
thunkParams,
/*vararg*/ false);
auto accessorThunk = llvm::Function::Create(thunkType,
llvm::GlobalValue::PrivateLinkage, thunkName, IGM.getModule());
accessorThunk->setAttributes(IGM.constructInitialAttributes());
accessorThunk->setCallingConv(IGM.SwiftCC);
switch (whichAccessor) {
case Getter:
// Original accessor's args should be @in or @out, meaning they won't be
// captured or aliased.
accessorThunk->addAttribute(1, llvm::Attribute::NoCapture);
accessorThunk->addAttribute(1, llvm::Attribute::NoAlias);
accessorThunk->addAttribute(2, llvm::Attribute::NoCapture);
accessorThunk->addAttribute(2, llvm::Attribute::NoAlias);
// Output is sret.
accessorThunk->addAttribute(1, llvm::Attribute::StructRet);
break;
case Setter:
// Original accessor's args should be @in or @out, meaning they won't be
// captured or aliased.
accessorThunk->addAttribute(1, llvm::Attribute::NoCapture);
accessorThunk->addAttribute(1, llvm::Attribute::NoAlias);
accessorThunk->addAttribute(2, llvm::Attribute::NoCapture);
accessorThunk->addAttribute(2, llvm::Attribute::NoAlias);
break;
case Equals:
case Hash:
break;
}
{
IRGenFunction IGF(IGM, accessorThunk);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, accessorThunk);
auto params = IGF.collectParameters();
Explosion forwardedArgs;
forwardedArgs.add(params.claim(numArgsToForward));
llvm::Value *componentArgsBuf;
switch (whichAccessor) {
case Getter:
case Setter:
// The component arguments are passed alongside the base being projected.
componentArgsBuf = params.claimNext();
// Pass the argument pointer down to the underlying function, if it
// wants it.
if (hasSubscriptIndices) {
forwardedArgs.add(componentArgsBuf);
}
break;
case Equals:
case Hash:
// We're operating directly on the component argument buffer.
componentArgsBuf = forwardedArgs.getAll()[0];
break;
}
auto componentArgsBufSize = params.claimNext();
bindPolymorphicArgumentsFromComponentIndices(IGF, component,
genericEnv, requirements,
componentArgsBuf,
componentArgsBufSize,
hasSubscriptIndices);
// Use the bound generic metadata to form a call to the original generic
// accessor.
WitnessMetadata ignoreWitnessMetadata;
auto forwardingSubs = genericEnv->getForwardingSubstitutionMap();
emitPolymorphicArguments(IGF, accessor->getLoweredFunctionType(),
forwardingSubs,
&ignoreWitnessMetadata,
forwardedArgs);
auto fnPtr = FunctionPointer::forDirect(IGM, accessorFn,
accessor->getLoweredFunctionType());
auto call = IGF.Builder.CreateCall(fnPtr, forwardedArgs.claimAll());
if (call->getType()->isVoidTy())
IGF.Builder.CreateRetVoid();
else
IGF.Builder.CreateRet(call);
}
return accessorThunk;
}
static llvm::Constant *
getLayoutFunctionForComputedComponent(IRGenModule &IGM,
const KeyPathPatternComponent &component,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements) {
// Generate a function that returns the expected size and alignment necessary
// to store captured generic context and subscript index arguments.
auto retTy = llvm::StructType::get(IGM.getLLVMContext(),
{IGM.SizeTy, IGM.SizeTy});
auto fnTy = llvm::FunctionType::get(
retTy, { IGM.Int8PtrTy }, /*vararg*/ false);
auto layoutFn = llvm::Function::Create(fnTy,
llvm::GlobalValue::PrivateLinkage, "keypath_get_arg_layout", IGM.getModule());
{
IRGenFunction IGF(IGM, layoutFn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, layoutFn);
// Unmarshal the generic environment from the argument buffer.
auto parameters = IGF.collectParameters();
auto args = parameters.claimNext();
if (genericEnv) {
bindFromGenericRequirementsBuffer(IGF, requirements,
Address(args, IGF.IGM.getPointerAlignment()),
MetadataState::Complete,
[&](CanType t) {
return genericEnv->mapTypeIntoContext(t)->getCanonicalType();
});
}
// Run through the captured index types to determine the size and alignment
// needed. Start with pointer alignment for the generic environment.
llvm::Value *size = llvm::ConstantInt::get(IGM.SizeTy, 0);
llvm::Value *alignMask = llvm::ConstantInt::get(IGM.SizeTy, 0);
for (auto &index : component.getSubscriptIndices()) {
auto ty = genericEnv
? genericEnv->mapTypeIntoContext(IGM.getSILModule(), index.LoweredType)
: index.LoweredType;
auto &ti = IGM.getTypeInfo(ty);
auto indexSize = ti.getSize(IGF, ty);
auto indexAlign = ti.getAlignmentMask(IGF, ty);
auto notIndexAlign = IGF.Builder.CreateNot(indexAlign);
size = IGF.Builder.CreateAdd(size, indexAlign);
size = IGF.Builder.CreateAnd(size, notIndexAlign);
size = IGF.Builder.CreateAdd(size, indexSize);
alignMask = IGF.Builder.CreateOr(alignMask, indexAlign);
}
// If there's generic environment to capture, then it's stored as a block
// of pointer-aligned words after the captured values.
auto genericsSize = llvm::ConstantInt::get(IGM.SizeTy,
IGM.getPointerSize().getValue() * requirements.size());
auto genericsAlign = llvm::ConstantInt::get(IGM.SizeTy,
IGM.getPointerAlignment().getValue() - 1);
auto notGenericsAlign = llvm::ConstantExpr::getNot(genericsAlign);
size = IGF.Builder.CreateAdd(size, genericsAlign);
size = IGF.Builder.CreateAnd(size, notGenericsAlign);
size = IGF.Builder.CreateAdd(size, genericsSize);
alignMask = IGF.Builder.CreateOr(alignMask, genericsAlign);
llvm::Value *retValue = IGF.Builder.CreateInsertValue(
llvm::UndefValue::get(retTy), size, 0);
retValue = IGF.Builder.CreateInsertValue(
retValue, alignMask, 1);
IGF.Builder.CreateRet(retValue);
}
return layoutFn;
}
static llvm::Constant *
getWitnessTableForComputedComponent(IRGenModule &IGM,
const KeyPathPatternComponent &component,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements) {
// If the only thing we're capturing is generic environment, then we can
// use a prefab witness table from the runtime.
if (component.getSubscriptIndices().empty()) {
if (auto existing =
IGM.Module.getNamedGlobal("swift_keyPathGenericWitnessTable"))
return existing;
auto linkInfo = LinkInfo::get(UniversalLinkageInfo(IGM),
"swift_keyPathGenericWitnessTable",
SILLinkage::PublicExternal, NotForDefinition,
/*weak imported*/ false);
return createVariable(IGM, linkInfo,
IGM.Int8PtrTy, IGM.getPointerAlignment());
}
// Are the index values trivial?
bool isTrivial = true;
for (auto &component : component.getSubscriptIndices()) {
auto ty = genericEnv
? genericEnv->mapTypeIntoContext(IGM.getSILModule(), component.LoweredType)
: component.LoweredType;
auto &ti = IGM.getTypeInfo(ty);
isTrivial &= ti.isPOD(ResilienceExpansion::Minimal);
}
llvm::Constant *destroy;
llvm::Constant *copy;
if (isTrivial) {
// We can use prefab witnesses for handling trivial copying and destruction.
// A null destructor witness signals that the payload is trivial.
destroy = llvm::ConstantPointerNull::get(IGM.Int8PtrTy);
copy = IGM.getCopyKeyPathTrivialIndicesFn();
} else {
// Generate a destructor for this set of indices.
{
auto destroyType = llvm::FunctionType::get(IGM.VoidTy,
{IGM.Int8PtrTy, IGM.SizeTy},
/*vararg*/ false);
auto destroyFn = llvm::Function::Create(destroyType,
llvm::GlobalValue::PrivateLinkage, "keypath_destroy", IGM.getModule());
destroy = destroyFn;
IRGenFunction IGF(IGM, destroyFn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, destroyFn);
auto params = IGF.collectParameters();
auto componentArgsBuf = params.claimNext();
auto componentArgsBufSize = params.claimNext();
bindPolymorphicArgumentsFromComponentIndices(IGF, component,
genericEnv, requirements,
componentArgsBuf,
componentArgsBufSize,
!component.getSubscriptIndices().empty());
llvm::Value *offset = nullptr;
for (auto &component : component.getSubscriptIndices()) {
auto ty = genericEnv
? genericEnv->mapTypeIntoContext(IGM.getSILModule(),
component.LoweredType)
: component.LoweredType;
auto &ti = IGM.getTypeInfo(ty);
if (offset) {
auto align = ti.getAlignmentMask(IGF, ty);
auto notAlign = IGF.Builder.CreateNot(align);
offset = IGF.Builder.CreateAdd(offset, align);
offset = IGF.Builder.CreateAnd(offset, notAlign);
} else {
offset = llvm::ConstantInt::get(IGM.SizeTy, 0);
}
auto elt = IGF.Builder.CreateInBoundsGEP(componentArgsBuf, offset);
auto eltAddr = ti.getAddressForPointer(
IGF.Builder.CreateBitCast(elt, ti.getStorageType()->getPointerTo()));
ti.destroy(IGF, eltAddr, ty,
true /*witness table: need it to be fast*/);
auto size = ti.getSize(IGF, ty);
offset = IGF.Builder.CreateAdd(offset, size);
}
IGF.Builder.CreateRetVoid();
}
// Generate a copier for this set of indices.
{
auto copyType = llvm::FunctionType::get(IGM.VoidTy,
{IGM.Int8PtrTy, IGM.Int8PtrTy,
IGM.SizeTy},
/*vararg*/ false);
auto copyFn = llvm::Function::Create(copyType,
llvm::GlobalValue::PrivateLinkage, "keypath_copy", IGM.getModule());
copy = copyFn;
IRGenFunction IGF(IGM, copyFn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, copyFn);
auto params = IGF.collectParameters();
auto sourceArgsBuf = params.claimNext();
auto destArgsBuf = params.claimNext();
auto componentArgsBufSize = params.claimNext();
bindPolymorphicArgumentsFromComponentIndices(IGF, component,
genericEnv, requirements,
sourceArgsBuf,
componentArgsBufSize,
!component.getSubscriptIndices().empty());
// Copy over the index values.
llvm::Value *offset = nullptr;
for (auto &component : component.getSubscriptIndices()) {
auto ty = genericEnv
? genericEnv->mapTypeIntoContext(IGM.getSILModule(),
component.LoweredType)
: component.LoweredType;
auto &ti = IGM.getTypeInfo(ty);
if (offset) {
auto align = ti.getAlignmentMask(IGF, ty);
auto notAlign = IGF.Builder.CreateNot(align);
offset = IGF.Builder.CreateAdd(offset, align);
offset = IGF.Builder.CreateAnd(offset, notAlign);
} else {
offset = llvm::ConstantInt::get(IGM.SizeTy, 0);
}
auto sourceElt = IGF.Builder.CreateInBoundsGEP(sourceArgsBuf, offset);
auto destElt = IGF.Builder.CreateInBoundsGEP(destArgsBuf, offset);
auto sourceEltAddr = ti.getAddressForPointer(
IGF.Builder.CreateBitCast(sourceElt,
ti.getStorageType()->getPointerTo()));
auto destEltAddr = ti.getAddressForPointer(
IGF.Builder.CreateBitCast(destElt,
ti.getStorageType()->getPointerTo()));
ti.initializeWithCopy(IGF, destEltAddr, sourceEltAddr, ty, false);
auto size = ti.getSize(IGF, ty);
offset = IGF.Builder.CreateAdd(offset, size);
}
// Copy over the generic environment.
if (genericEnv) {
auto envAlignMask = llvm::ConstantInt::get(IGM.SizeTy,
IGM.getPointerAlignment().getMaskValue());
auto notAlignMask = IGF.Builder.CreateNot(envAlignMask);
offset = IGF.Builder.CreateAdd(offset, envAlignMask);
offset = IGF.Builder.CreateAnd(offset, notAlignMask);
auto sourceEnv = IGF.Builder.CreateInBoundsGEP(sourceArgsBuf, offset);
auto destEnv = IGF.Builder.CreateInBoundsGEP(destArgsBuf, offset);
IGF.Builder.CreateMemCpy(destEnv, sourceEnv,
IGM.getPointerSize().getValue() * requirements.size(),
IGM.getPointerAlignment().getValue());
}
IGF.Builder.CreateRetVoid();
}
}
auto equals = getAccessorForComputedComponent(IGM, component, Equals,
genericEnv, requirements,
!component.getSubscriptIndices().empty());
auto hash = getAccessorForComputedComponent(IGM, component, Hash,
genericEnv, requirements,
!component.getSubscriptIndices().empty());
auto witnesses = llvm::ConstantStruct::getAnon({destroy, copy, equals, hash});
return new llvm::GlobalVariable(IGM.Module, witnesses->getType(),
/*constant*/ true,
llvm::GlobalValue::PrivateLinkage,
witnesses,
"keypath_witnesses");
}
/// Information about each index operand for a key path pattern that is used
/// to lay out and consume the argument packet.
struct KeyPathIndexOperand {
SILType LoweredType;
const KeyPathPatternComponent *LastUser;
};
static llvm::Constant *
getInitializerForComputedComponent(IRGenModule &IGM,
const KeyPathPatternComponent &component,
ArrayRef<KeyPathIndexOperand> operands,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements) {
auto fnTy = llvm::FunctionType::get(IGM.VoidTy,
{ /*src*/ IGM.Int8PtrTy,
/*dest*/ IGM.Int8PtrTy }, /*vararg*/ false);
auto initFn = llvm::Function::Create(fnTy,
llvm::GlobalValue::PrivateLinkage, "keypath_arg_init", IGM.getModule());
{
IRGenFunction IGF(IGM, initFn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, initFn);
auto params = IGF.collectParameters();
// Pointer to the argument packet passed into swift_getKeyPath
auto src = params.claimNext();
// Pointer to the destination component's argument buffer
auto dest = params.claimNext();
SmallVector<Address, 4> srcAddresses;
int lastOperandNeeded = -1;
for (auto &index : component.getSubscriptIndices()) {
lastOperandNeeded = std::max(lastOperandNeeded, (int)index.Operand);
}
llvm::Value *offset;
if (genericEnv) {
// We'll copy over the generic environment after we copy in the indexes.
offset = llvm::ConstantInt::get(IGM.SizeTy,
IGM.getPointerSize().getValue() * requirements.size());
// Bind the generic environment from the argument buffer.
bindFromGenericRequirementsBuffer(IGF, requirements,
Address(src, IGF.IGM.getPointerAlignment()),
MetadataState::Complete,
[&](CanType t) {
return genericEnv->mapTypeIntoContext(t)->getCanonicalType();
});
} else {
offset = llvm::ConstantInt::get(IGM.SizeTy, 0);
}
// Figure out the offsets of the operands in the source buffer.
for (int i = 0; i <= lastOperandNeeded; ++i) {
auto ty = genericEnv
? genericEnv->mapTypeIntoContext(IGM.getSILModule(),
operands[i].LoweredType)
: operands[i].LoweredType;
auto &ti = IGM.getTypeInfo(ty);
if (i != 0 || genericEnv) {
auto alignMask = ti.getAlignmentMask(IGF, ty);
auto notAlignMask = IGF.Builder.CreateNot(alignMask);
offset = IGF.Builder.CreateAdd(offset, alignMask);
offset = IGF.Builder.CreateAnd(offset, notAlignMask);
}
auto ptr = IGF.Builder.CreateInBoundsGEP(src, offset);
auto addr = ti.getAddressForPointer(IGF.Builder.CreateBitCast(
ptr, ti.getStorageType()->getPointerTo()));
srcAddresses.push_back(addr);
auto size = ti.getSize(IGF, ty);
offset = IGF.Builder.CreateAdd(offset, size);
}
offset = llvm::ConstantInt::get(IGM.SizeTy, 0);
// Transfer the operands we want into the destination buffer.
for (unsigned i : indices(component.getSubscriptIndices())) {
auto &index = component.getSubscriptIndices()[i];
auto ty = genericEnv
? genericEnv->mapTypeIntoContext(IGM.getSILModule(),
index.LoweredType)
: index.LoweredType;
auto &ti = IGM.getTypeInfo(ty);
if (i != 0) {
auto alignMask = ti.getAlignmentMask(IGF, ty);
auto notAlignMask = IGF.Builder.CreateNot(alignMask);
offset = IGF.Builder.CreateAdd(offset, alignMask);
offset = IGF.Builder.CreateAnd(offset, notAlignMask);
}
auto ptr = IGF.Builder.CreateInBoundsGEP(dest, offset);
auto destAddr = ti.getAddressForPointer(IGF.Builder.CreateBitCast(
ptr, ti.getStorageType()->getPointerTo()));
// The last component using an operand can move the value out of the
// buffer.
if (&component == operands[index.Operand].LastUser) {
ti.initializeWithTake(IGF, destAddr, srcAddresses[index.Operand], ty,
false);
} else {
ti.initializeWithCopy(IGF, destAddr, srcAddresses[index.Operand], ty,
false);
}
auto size = ti.getSize(IGF, ty);
offset = IGF.Builder.CreateAdd(offset, size);
}
// Transfer the generic environment.
// External components don't need to store the key path environment (and
// can't), since they need to already have enough information to function
// independently of any context using the component.
if (genericEnv &&
component.getKind() != KeyPathPatternComponent::Kind::External) {
auto destGenericEnv = dest;
if (!component.getSubscriptIndices().empty()) {
auto genericEnvAlignMask = llvm::ConstantInt::get(IGM.SizeTy,
IGM.getPointerAlignment().getMaskValue());
auto notGenericEnvAlignMask = IGF.Builder.CreateNot(genericEnvAlignMask);
offset = IGF.Builder.CreateAdd(offset, genericEnvAlignMask);
offset = IGF.Builder.CreateAnd(offset, notGenericEnvAlignMask);
destGenericEnv = IGF.Builder.CreateInBoundsGEP(dest, offset);
}
IGF.Builder.CreateMemCpy(destGenericEnv, src,
IGM.getPointerSize().getValue() * requirements.size(),
IGM.getPointerAlignment().getValue());
}
IGF.Builder.CreateRetVoid();
}
return initFn;
}
/// Emit a generator function to produce a reference to a type or
/// protocol conformance metadata record.
/// TODO: It would be much better to emit typeref strings and use runtime
/// demangling here.
static llvm::Function *
emitGeneratorForKeyPath(IRGenModule &IGM,
StringRef name, CanType type, llvm::Type *returnType,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements,
llvm::function_ref<void(IRGenFunction&,CanType)> emit) {
// TODO: Use the standard metadata accessor when there are no arguments
// and the metadata accessor is defined.
// Build a stub that loads the necessary bindings from the key path's
// argument buffer then fetches the metadata.
auto fnTy = llvm::FunctionType::get(returnType,
{IGM.Int8PtrTy}, /*vararg*/ false);
auto accessorThunk = llvm::Function::Create(fnTy,
llvm::GlobalValue::PrivateLinkage,
name, IGM.getModule());
accessorThunk->setAttributes(IGM.constructInitialAttributes());
{
IRGenFunction IGF(IGM, accessorThunk);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(IGF, accessorThunk);
if (type->hasTypeParameter()) {
auto bindingsBufPtr = IGF.collectParameters().claimNext();
bindFromGenericRequirementsBuffer(IGF, requirements,
Address(bindingsBufPtr, IGM.getPointerAlignment()),
MetadataState::Complete,
[&](CanType t) {
return genericEnv->mapTypeIntoContext(t)->getCanonicalType();
});
type = genericEnv->mapTypeIntoContext(type)->getCanonicalType();
}
emit(IGF, type);
}
return accessorThunk;
}
static llvm::Function *
emitMetadataGeneratorForKeyPath(IRGenModule &IGM,
CanType type,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements) {
// TODO: Use the standard metadata accessor when there are no arguments
// and the metadata accessor is defined.
return emitGeneratorForKeyPath(IGM, "keypath_get_type", type,
IGM.TypeMetadataPtrTy,
genericEnv, requirements,
[&](IRGenFunction &IGF, CanType substType) {
auto ret = IGF.emitTypeMetadataRef(substType);
IGF.Builder.CreateRet(ret);
});
};
static llvm::Function *
emitWitnessTableGeneratorForKeyPath(IRGenModule &IGM,
CanType type,
ProtocolConformanceRef conformance,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements) {
// TODO: Use the standard conformance accessor when there are no arguments
// and the conformance accessor is defined.
return emitGeneratorForKeyPath(IGM, "keypath_get_witness_table", type,
IGM.WitnessTablePtrTy,
genericEnv, requirements,
[&](IRGenFunction &IGF, CanType substType) {
if (type->hasTypeParameter())
conformance = conformance.subst(type,
QueryInterfaceTypeSubstitutions(genericEnv),
LookUpConformanceInSignature(*genericEnv->getGenericSignature()));
auto ret = emitWitnessTableRef(IGF, substType, conformance);
IGF.Builder.CreateRet(ret);
});
}
static void
emitKeyPathComponent(IRGenModule &IGM,
ConstantStructBuilder &fields,
const KeyPathPatternComponent &component,
bool isInstantiableInPlace,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements,
CanType baseTy,
ArrayRef<KeyPathIndexOperand> operands,
bool hasSubscriptIndices) {
assert(fields.getNextOffsetFromGlobal() % IGM.getPointerAlignment() == Size(0)
&& "must be pointer-aligned here");
SILType loweredBaseTy;
GenericContextScope scope(IGM,
genericEnv ? genericEnv->getGenericSignature()->getCanonicalSignature()
: nullptr);
loweredBaseTy = IGM.getLoweredType(AbstractionPattern::getOpaque(),
baseTy->getWithoutSpecifierType());
switch (auto kind = component.getKind()) {
case KeyPathPatternComponent::Kind::External: {
fields.addInt32(KeyPathComponentHeader::forExternalComponent().getData());
// Emit accessors for all of the external declaration's necessary
// bindings.
SmallVector<llvm::Constant*, 4> descriptorArgs;
auto componentSig = component.getExternalDecl()->getInnermostDeclContext()
->getGenericSignatureOfContext();
auto subs = component.getExternalSubstitutions();
enumerateGenericSignatureRequirements(
componentSig->getCanonicalSignature(),
[&](GenericRequirement reqt) {
auto substType = reqt.TypeParameter.subst(subs)
->getCanonicalType();
if (!reqt.Protocol) {
// Type requirement.
descriptorArgs.push_back(
emitMetadataGeneratorForKeyPath(IGM, substType,
genericEnv, requirements));
} else {
// Protocol requirement.
auto conformance = subs.lookupConformance(
reqt.TypeParameter->getCanonicalType(), reqt.Protocol);
descriptorArgs.push_back(
emitWitnessTableGeneratorForKeyPath(IGM, substType,
*conformance,
genericEnv, requirements));
}
});
// If instantiable in-place, pad out the argument count here to ensure
// there's room enough to instantiate a settable computed property
// with two captured words in-place. The runtime instantiation of the
// external component will ignore the padding, and this will make in-place
// instantiation more likely to avoid needing an allocation.
unsigned argSize = descriptorArgs.size();
if (isInstantiableInPlace) {
argSize = std::max(argSize, 3u);
}
fields.addInt32(argSize);
fields.add(IGM.getAddrOfPropertyDescriptor(component.getExternalDecl()));
// Add an initializer function that copies generic arguments out of the
// pattern argument buffer into the instantiated object, along with the
// index equality/hash operations we have from our perspective, or null
// if there are no arguments.
if (component.getSubscriptIndices().empty()) {
fields.addInt(IGM.IntPtrTy, 0);
fields.addInt(IGM.IntPtrTy, 0);
fields.addInt(IGM.IntPtrTy, 0);
} else {
fields.add(getInitializerForComputedComponent(IGM, component,
operands,
genericEnv,
requirements));
fields.add(IGM.getAddrOfSILFunction(component.getSubscriptIndexEquals(),
NotForDefinition));
fields.add(IGM.getAddrOfSILFunction(component.getSubscriptIndexHash(),
NotForDefinition));
}
// Add the generic arguments for the external context.
for (auto arg : descriptorArgs)
fields.add(arg);
// Add padding.
for (unsigned i = descriptorArgs.size(); i < argSize; ++i)
fields.addInt(IGM.IntPtrTy, 0);
break;
}
case KeyPathPatternComponent::Kind::StoredProperty: {
auto property = cast<VarDecl>(component.getStoredPropertyDecl());
auto addFixedOffset = [&](bool isStruct, llvm::Constant *offset) {
if (auto offsetInt = dyn_cast_or_null<llvm::ConstantInt>(offset)) {
auto offsetValue = offsetInt->getValue().getZExtValue();
if (KeyPathComponentHeader::offsetCanBeInline(offsetValue)) {
auto header = isStruct
? KeyPathComponentHeader
::forStructComponentWithInlineOffset(offsetValue)
: KeyPathComponentHeader
::forClassComponentWithInlineOffset(offsetValue);
fields.addInt32(header.getData());
return;
}
}
auto header = isStruct
? KeyPathComponentHeader::forStructComponentWithOutOfLineOffset()
: KeyPathComponentHeader::forClassComponentWithOutOfLineOffset();
fields.addInt32(header.getData());
fields.add(llvm::ConstantExpr::getTruncOrBitCast(offset, IGM.Int32Ty));
};
// For a struct stored property, we may know the fixed offset of the field,
// or we may need to fetch it out of the type's metadata at instantiation
// time.
if (auto theStruct = loweredBaseTy.getStructOrBoundGenericStruct()) {
if (auto offset = emitPhysicalStructMemberFixedOffset(IGM,
loweredBaseTy,
property)) {
// We have a known constant fixed offset.
addFixedOffset(/*struct*/ true, offset);
break;
}
// If the offset isn't fixed, try instead to get the field offset out
// of the type metadata at instantiation time.
auto &metadataLayout = IGM.getMetadataLayout(theStruct);
auto fieldOffset = metadataLayout.getStaticFieldOffset(property);
auto header = KeyPathComponentHeader
::forStructComponentWithUnresolvedFieldOffset();
fields.addInt32(header.getData());
fields.addInt32(fieldOffset.getValue());
break;
}
// For a class, we may know the fixed offset of a field at compile time,
// or we may need to fetch it at instantiation time. Depending on the
// ObjC-ness and resilience of the class hierarchy, there might be a few
// different ways we need to go about this.
if (loweredBaseTy.getClassOrBoundGenericClass()) {
switch (getClassFieldAccess(IGM, loweredBaseTy, property)) {
case FieldAccess::ConstantDirect: {
// Known constant fixed offset.
auto offset = tryEmitConstantClassFragilePhysicalMemberOffset(IGM,
loweredBaseTy,
property);
assert(offset && "no constant offset for ConstantDirect field?!");
addFixedOffset(/*struct*/ false, offset);
break;
}
case FieldAccess::NonConstantDirect: {
// A constant offset that's determined at class realization time.
// We have to load the offset from a global ivar.
auto header = KeyPathComponentHeader
::forClassComponentWithUnresolvedIndirectOffset();
fields.addInt32(header.getData());
fields.addAlignmentPadding(IGM.getPointerAlignment());
auto offsetVar = IGM.getAddrOfFieldOffset(property, NotForDefinition);
fields.add(cast<llvm::Constant>(offsetVar.getAddress()));
break;
}
case FieldAccess::ConstantIndirect: {
// An offset that depends on the instance's generic parameterization,
// but whose field offset is at a known vtable offset.
auto header =
KeyPathComponentHeader::forClassComponentWithUnresolvedFieldOffset();
fields.addInt32(header.getData());
auto fieldOffset =
getClassFieldOffsetOffset(IGM,
loweredBaseTy.getClassOrBoundGenericClass(),
property);
fields.addInt32(fieldOffset.getValue());
break;
}
}
break;
}
llvm_unreachable("not struct or class");
}
case KeyPathPatternComponent::Kind::GettableProperty:
case KeyPathPatternComponent::Kind::SettableProperty: {
// Encode the settability.
bool settable = kind == KeyPathPatternComponent::Kind::SettableProperty;
KeyPathComponentHeader::ComputedPropertyKind componentKind;
if (settable) {
componentKind = component.isComputedSettablePropertyMutating()
? KeyPathComponentHeader::SettableMutating
: KeyPathComponentHeader::SettableNonmutating;
} else {
componentKind = KeyPathComponentHeader::GetOnly;
}
// Lower the id reference.
auto id = component.getComputedPropertyId();
KeyPathComponentHeader::ComputedPropertyIDKind idKind;
llvm::Constant *idValue;
bool idResolved;
switch (id.getKind()) {
case KeyPathPatternComponent::ComputedPropertyId::Function:
idKind = KeyPathComponentHeader::Pointer;
idValue = IGM.getAddrOfSILFunction(id.getFunction(), NotForDefinition);
idResolved = true;
break;
case KeyPathPatternComponent::ComputedPropertyId::DeclRef: {
auto declRef = id.getDeclRef();
// Foreign method refs identify using a selector
// reference, which is doubly-indirected and filled in with a unique
// pointer by dyld.
if (declRef.isForeign) {
assert(IGM.ObjCInterop && "foreign keypath component w/o objc interop?!");
idKind = KeyPathComponentHeader::Pointer;
idValue = IGM.getAddrOfObjCSelectorRef(declRef);
idResolved = false;
} else {
idKind = KeyPathComponentHeader::VTableOffset;
auto dc = declRef.getDecl()->getDeclContext();
if (isa<ClassDecl>(dc) && !cast<ClassDecl>(dc)->isForeign()) {
auto overridden = declRef.getOverriddenVTableEntry();
auto declaringClass =
cast<ClassDecl>(overridden.getDecl()->getDeclContext());
auto &metadataLayout = IGM.getClassMetadataLayout(declaringClass);
// FIXME: Resilience. We don't want vtable layout to be ABI, so this
// should be encoded as a reference to the method dispatch thunk
// instead.
auto offset = metadataLayout.getStaticMethodOffset(overridden);
idValue = llvm::ConstantInt::get(IGM.SizeTy, offset.getValue());
idResolved = true;
} else if (auto methodProto = dyn_cast<ProtocolDecl>(dc)) {
// FIXME: Resilience. We don't want witness table layout to be ABI,
// so this should be encoded as a reference to the method dispatch
// thunk instead.
auto &protoInfo = IGM.getProtocolInfo(methodProto);
auto index = protoInfo.getFunctionIndex(
cast<AbstractFunctionDecl>(declRef.getDecl()));
idValue = llvm::ConstantInt::get(IGM.SizeTy, -index.getValue());
idResolved = true;
} else {
llvm_unreachable("neither a class nor protocol dynamic method?");
}
}
break;
}
case KeyPathPatternComponent::ComputedPropertyId::Property:
// Use the index of the stored property within the aggregate to key
// the property.
auto property = id.getProperty();
idKind = KeyPathComponentHeader::StoredPropertyIndex;
if (auto struc = baseTy->getStructOrBoundGenericStruct()) {
// Scan the stored properties of the struct to find the index. We should
// only ever use a struct field as a uniquing key from inside the
// struct's own module, so this is OK.
idResolved = true;
Optional<unsigned> structIdx;
unsigned i = 0;
for (auto storedProp : struc->getStoredProperties()) {
if (storedProp == property) {
structIdx = i;
break;
}
++i;
}
assert(structIdx && "not a stored property of the struct?!");
idValue = llvm::ConstantInt::get(IGM.SizeTy, structIdx.getValue());
} else if (baseTy->getClassOrBoundGenericClass()) {
// TODO: This field index would require runtime resolution with Swift
// native class resilience. We never directly access ObjC-imported
// ivars so we can disregard ObjC ivar resilience for this computation
// and start counting at the Swift native root.
switch (getClassFieldAccess(IGM, loweredBaseTy, property)) {
case FieldAccess::ConstantDirect:
case FieldAccess::ConstantIndirect:
case FieldAccess::NonConstantDirect:
idResolved = true;
idValue = llvm::ConstantInt::get(IGM.SizeTy,
getClassFieldIndex(IGM,
SILType::getPrimitiveAddressType(baseTy), property));
break;
}
} else {
llvm_unreachable("neither struct nor class");
}
break;
}
auto header = KeyPathComponentHeader::forComputedProperty(componentKind,
idKind, !isInstantiableInPlace, idResolved);
fields.addInt32(header.getData());
fields.addAlignmentPadding(IGM.getPointerAlignment());
fields.add(idValue);
if (isInstantiableInPlace) {
// No generic arguments or indexes, so we can invoke the
// getter/setter as is.
fields.add(IGM.getAddrOfSILFunction(component.getComputedPropertyGetter(),
NotForDefinition));
if (settable)
fields.add(IGM.getAddrOfSILFunction(component.getComputedPropertySetter(),
NotForDefinition));
} else {
// If there's generic context or subscript indexes, embed as
// arguments in the component. Thunk the SIL-level accessors to give the
// runtime implementation a polymorphically-callable interface.
// Push the accessors, possibly thunked to marshal generic environment.
fields.add(getAccessorForComputedComponent(IGM, component, Getter,
genericEnv, requirements,
hasSubscriptIndices));
if (settable)
fields.add(getAccessorForComputedComponent(IGM, component, Setter,
genericEnv, requirements,
hasSubscriptIndices));
fields.add(getLayoutFunctionForComputedComponent(IGM, component,
genericEnv, requirements));
// Set up a "witness table" for the component that handles copying,
// destroying, equating, and hashing the captured contents of the
// component.
// If there are only generic parameters, we can use a prefab witness
// table from the runtime.
// For subscripts we generate functions that dispatch out to
// the copy/destroy/equals/hash functionality of the subscript indexes.
fields.add(getWitnessTableForComputedComponent(IGM, component,
genericEnv, requirements));
// Add an initializer function that copies generic arguments out of the
// pattern argument buffer into the instantiated object.
fields.add(getInitializerForComputedComponent(IGM, component, operands,
genericEnv, requirements));
}
break;
}
case KeyPathPatternComponent::Kind::OptionalChain:
fields.addInt32(KeyPathComponentHeader::forOptionalChain().getData());
break;
case KeyPathPatternComponent::Kind::OptionalForce:
fields.addInt32(KeyPathComponentHeader::forOptionalForce().getData());
break;
case KeyPathPatternComponent::Kind::OptionalWrap:
fields.addInt32(KeyPathComponentHeader::forOptionalWrap().getData());
break;
}
}
llvm::Constant *
IRGenModule::getAddrOfKeyPathPattern(KeyPathPattern *pattern,
SILLocation diagLoc) {
// See if we already emitted this.
auto found = KeyPathPatterns.find(pattern);
if (found != KeyPathPatterns.end())
return found->second;
// Gather type arguments from the root and leaf types of the key path.
auto rootTy = pattern->getRootType();
auto valueTy = pattern->getValueType();
// Check for parameterization, whether by subscript indexes or by the generic
// environment. If there isn't any, we can instantiate the pattern in-place.
bool isInstantiableInPlace = pattern->getNumOperands() == 0
&& !pattern->getGenericSignature();
// Collect the required parameters for the keypath's generic environment.
SmallVector<GenericRequirement, 4> requirements;
GenericEnvironment *genericEnv = nullptr;
if (auto sig = pattern->getGenericSignature()) {
genericEnv = sig->createGenericEnvironment();
enumerateGenericSignatureRequirements(pattern->getGenericSignature(),
[&](GenericRequirement reqt) { requirements.push_back(reqt); });
}
// Start building the key path pattern.
ConstantInitBuilder builder(*this);
ConstantStructBuilder fields = builder.beginStruct();
fields.setPacked(true);
// Add a zero-initialized header we can use for lazy initialization.
fields.add(llvm::ConstantInt::get(SizeTy, 0));
#ifndef NDEBUG
auto startOfObject = fields.getNextOffsetFromGlobal();
#endif
// Store references to metadata generator functions to generate the metadata
// for the root and leaf. These sit in the "isa" and object header parts of
// the final object.
fields.add(emitMetadataGeneratorForKeyPath(*this, rootTy,
genericEnv, requirements));
fields.add(emitMetadataGeneratorForKeyPath(*this, valueTy,
genericEnv, requirements));
#ifndef NDEBUG
auto endOfObjectHeader = fields.getNextOffsetFromGlobal();
unsigned expectedObjectHeaderSize;
if (SizeTy == Int64Ty)
expectedObjectHeaderSize = SWIFT_ABI_HEAP_OBJECT_HEADER_SIZE_64;
else if (SizeTy == Int32Ty)
expectedObjectHeaderSize = SWIFT_ABI_HEAP_OBJECT_HEADER_SIZE_32;
else
llvm_unreachable("unexpected pointer size");
assert((endOfObjectHeader - startOfObject).getValue()
== expectedObjectHeaderSize
&& "key path pattern header size doesn't match heap object header size");
#endif
// Add a pointer to the ObjC KVC compatibility string, if there is one, or
// null otherwise.
llvm::Constant *objcString;
if (!pattern->getObjCString().empty()) {
objcString = getAddrOfGlobalString(pattern->getObjCString());
} else {
objcString = llvm::ConstantPointerNull::get(Int8PtrTy);
}
fields.add(objcString);
// Leave a placeholder for the buffer header, since we need to know the full
// buffer size to fill it in.
auto headerPlaceholder = fields.addPlaceholderWithSize(Int32Ty);
fields.addAlignmentPadding(getPointerAlignment());
auto startOfKeyPathBuffer = fields.getNextOffsetFromGlobal();
// Build out the components.
auto baseTy = rootTy;
// Collect the order and types of any captured index operands, which will
// determine the layout of the buffer that gets passed to the initializer
// for each component.
SmallVector<KeyPathIndexOperand, 4> operands;
operands.resize(pattern->getNumOperands());
for (auto &component : pattern->getComponents()) {
switch (component.getKind()) {
case KeyPathPatternComponent::Kind::GettableProperty:
case KeyPathPatternComponent::Kind::SettableProperty:
case KeyPathPatternComponent::Kind::External:
for (auto &index : component.getSubscriptIndices()) {
operands[index.Operand].LoweredType = index.LoweredType;
operands[index.Operand].LastUser = &component;
}
break;
case KeyPathPatternComponent::Kind::StoredProperty:
case KeyPathPatternComponent::Kind::OptionalChain:
case KeyPathPatternComponent::Kind::OptionalForce:
case KeyPathPatternComponent::Kind::OptionalWrap:
break;
}
}
for (unsigned i : indices(pattern->getComponents())) {
auto &component = pattern->getComponents()[i];
emitKeyPathComponent(*this, fields, component, isInstantiableInPlace,
genericEnv, requirements,
baseTy, operands,
!component.getSubscriptIndices().empty());
// For all but the last component, we pack in the type of the component.
if (i + 1 != pattern->getComponents().size()) {
fields.addAlignmentPadding(getPointerAlignment());
fields.add(
emitMetadataGeneratorForKeyPath(*this, component.getComponentType(),
genericEnv, requirements));
}
baseTy = component.getComponentType();
}
// Save the total size of the buffer.
Size componentSize = fields.getNextOffsetFromGlobal()
- startOfKeyPathBuffer;
// We now have enough info to build the header.
KeyPathBufferHeader header(componentSize.getValue(), isInstantiableInPlace,
/*reference prefix*/ false);
// Add the header, followed by the components.
fields.fillPlaceholder(headerPlaceholder,
llvm::ConstantInt::get(Int32Ty, header.getData()));
// Create the global variable.
// TODO: The pattern could be immutable if
// it isn't instantiable in place, and if we made the type metadata accessor
// references private, it could go in true-const memory.
auto patternVar = fields.finishAndCreateGlobal("keypath",
getPointerAlignment(),
/*constant*/ false,
llvm::GlobalVariable::PrivateLinkage);
KeyPathPatterns.insert({pattern, patternVar});
return patternVar;
}
void IRGenModule::emitSILProperty(SILProperty *prop) {
ConstantInitBuilder builder(*this);
ConstantStructBuilder fields = builder.beginStruct();
fields.setPacked(true);
bool hasSubscriptIndices = false;
bool isInstantiableInPlace = true;
if (prop->getDecl()->getInnermostDeclContext()->isGenericContext()) {
isInstantiableInPlace = false;
}
if (auto subscript = dyn_cast<SubscriptDecl>(prop->getDecl())) {
hasSubscriptIndices = subscript->getIndices()->size() != 0;
isInstantiableInPlace &= !hasSubscriptIndices;
}
auto genericEnv = prop->getDecl()->getInnermostDeclContext()
->getGenericEnvironmentOfContext();
SmallVector<GenericRequirement, 4> requirements;
CanGenericSignature genericSig;
if (genericEnv) {
genericSig = prop->getDecl()->getInnermostDeclContext()
->getGenericSignatureOfContext()
->getCanonicalSignature();
enumerateGenericSignatureRequirements(genericSig,
[&](GenericRequirement reqt) { requirements.push_back(reqt); });
}
emitKeyPathComponent(*this, fields, prop->getComponent(),
isInstantiableInPlace, genericEnv, requirements,
prop->getDecl()->getInnermostDeclContext()
->getInnermostTypeContext()
->getSelfInterfaceType()
->getCanonicalType(genericSig),
{},
hasSubscriptIndices);
auto size = fields.getNextOffsetFromGlobal();
auto var = cast<llvm::GlobalVariable>(
getAddrOfPropertyDescriptor(prop->getDecl(),
fields.finishAndCreateFuture()));
var->setConstant(true);
// A simple stored component descriptor can fit in four bytes. Anything else
// needs pointer alignment.
if (size <= Size(4))
var->setAlignment(4);
else
var->setAlignment(getPointerAlignment().getValue());
}