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fuchsia / third_party / swift / refs/tags/swift-5.0-DEVELOPMENT-SNAPSHOT-2019-01-23-a / . / lib / IRGen / GenKeyPath.cpp
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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 "ClassLayout.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 "IRGenMangler.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 "llvm/IR/Function.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/Basic/Statistic.h"
#include "swift/IRGen/Linking.h"
using namespace swift;
using namespace irgen;
#define DEBUG_TYPE "IRGen key paths"
STATISTIC(NumTrivialPropertyDescriptors, "# of trivial property descriptors");
STATISTIC(NumNonTrivialPropertyDescriptors, "# of nontrivial property descriptors");
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;
}
// If the accessor is not generic, and locally available, we can use it as is.
// If it's only externally available, we need a local thunk to relative-
// reference.
if (requirements.empty() &&
!isAvailableExternally(accessor->getLinkage()) &&
&IGM == IGM.IRGen.getGenModule(accessor)) {
return IGM.getAddrOfSILFunction(accessor, NotForDefinition);
}
auto accessorFn = IGM.getAddrOfSILFunction(accessor, NotForDefinition);
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.
if (genericEnv) {
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. A null reference will be
// filled in by the runtime.
if (component.getSubscriptIndices().empty()) {
return nullptr;
}
// 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);
auto align = IGM.getPointerAlignment().getValue();
IGF.Builder.CreateMemCpy(destEnv, align, sourceEnv, align,
IGM.getPointerSize().getValue() * requirements.size());
}
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) {
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);
}
auto align = IGM.getPointerAlignment().getValue();
IGF.Builder.CreateMemCpy(destGenericEnv, align, src, align,
IGM.getPointerSize().getValue() * requirements.size());
}
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::Constant *
emitGeneratorForKeyPath(IRGenModule &IGM,
StringRef name, CanType type, llvm::Type *returnType,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements,
llvm::function_ref<void(IRGenFunction&,CanType)> emit) {
return IGM.getAddrOfStringForMetadataRef(name, /*alignment=*/2,
/*shouldSetLowBit=*/true,
[&](ConstantInitBuilder &B) {
// 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);
}
// Form the mangled name with its relative reference.
auto S = B.beginStruct();
S.setPacked(true);
S.add(llvm::ConstantInt::get(IGM.Int8Ty, 255));
S.add(llvm::ConstantInt::get(IGM.Int8Ty, 9));
S.addRelativeAddress(accessorThunk);
// And a null terminator!
S.addInt(IGM.Int8Ty, 0);
return S.finishAndCreateFuture();
});
}
static llvm::Constant *
emitMetadataGeneratorForKeyPath(IRGenModule &IGM,
CanType type,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements) {
// Produce a mangled name for the type.
auto constant = IGM.getTypeRef(type, MangledTypeRefRole::Metadata);
auto bitConstant = llvm::ConstantInt::get(IGM.IntPtrTy, 1);
return llvm::ConstantExpr::getGetElementPtr(nullptr, constant, bitConstant);
}
static llvm::Constant *
emitWitnessTableGeneratorForKeyPath(IRGenModule &IGM,
CanType type,
ProtocolConformanceRef conformance,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements) {
CanGenericSignature genericSig;
if (genericEnv)
genericSig = genericEnv->getGenericSignature()->getCanonicalSignature();
IRGenMangler mangler;
std::string symbolName =
mangler.mangleSymbolNameForKeyPathMetadata(
"keypath_get_witness_table", genericSig, type, conformance);
// TODO: Use the standard conformance accessor when there are no arguments
// and the conformance accessor is defined.
return emitGeneratorForKeyPath(IGM, symbolName, 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 unsigned getClassFieldIndex(ClassDecl *classDecl, VarDecl *property) {
SmallVector<ClassDecl *, 3> superclasses;
for (auto *superDecl = classDecl; superDecl != nullptr;
superDecl = superDecl->getSuperclassDecl()) {
superclasses.push_back(superDecl);
}
std::reverse(superclasses.begin(), superclasses.end());
unsigned index = 0;
for (auto *superDecl : superclasses) {
for (auto *other : superDecl->getStoredProperties()) {
if (other == property)
return index;
index++;
}
}
llvm_unreachable("Did not find stored property in class");
}
static void
emitKeyPathComponent(IRGenModule &IGM,
ConstantStructBuilder &fields,
const KeyPathPatternComponent &component,
bool isInstantiableOnce,
GenericEnvironment *genericEnv,
ArrayRef<GenericRequirement> requirements,
CanType baseTy,
ArrayRef<KeyPathIndexOperand> operands,
bool hasSubscriptIndices) {
assert(fields.getNextOffsetFromGlobal() % Alignment(4) == Size(0)
&& "must be 32-bit-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::StoredProperty: {
auto property = cast<VarDecl>(component.getStoredPropertyDecl());
auto addFixedOffset = [&](bool isStruct, bool isLet,
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(isLet, offsetValue)
: KeyPathComponentHeader
::forClassComponentWithInlineOffset(isLet, offsetValue);
fields.addInt32(header.getData());
return;
}
}
auto header = isStruct
? KeyPathComponentHeader::forStructComponentWithOutOfLineOffset(isLet)
: KeyPathComponentHeader::forClassComponentWithOutOfLineOffset(isLet);
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, property->isLet(), 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(property->isLet());
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()) {
// Use the property's class type to determine the field access.
auto propertyBaseDecl = property->getDeclContext()->getSelfClassDecl();
auto currentBaseTy =
loweredBaseTy.getASTType()->getSuperclassForDecl(propertyBaseDecl);
assert(currentBaseTy->getClassOrBoundGenericClass() == propertyBaseDecl);
loweredBaseTy =
IGM.getLoweredType(AbstractionPattern::getOpaque(), currentBaseTy);
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, property->isLet(), 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(property->isLet());
fields.addInt32(header.getData());
auto offsetRef = IGM.getAddrOfLLVMVariableOrGOTEquivalent(
LinkEntity::forFieldOffset(property));
fields.addRelativeAddress(offsetRef);
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(property->isLet());
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: {
// If the component references an external property, encode that in a
// header before the local attempt header, so that we can consult the
// external descriptor at instantiation time.
if (auto externalDecl = component.getExternalDecl()) {
SmallVector<llvm::Constant *, 4> externalSubArgs;
auto componentSig = externalDecl->getInnermostDeclContext()
->getGenericSignatureOfContext();
auto subs = component.getExternalSubstitutions();
if (!subs.empty()) {
enumerateGenericSignatureRequirements(
componentSig->getCanonicalSignature(),
[&](GenericRequirement reqt) {
auto substType = reqt.TypeParameter.subst(subs)
->getCanonicalType();
if (!reqt.Protocol) {
// Type requirement.
externalSubArgs.push_back(
emitMetadataGeneratorForKeyPath(IGM, substType,
genericEnv, requirements));
} else {
// Protocol requirement.
auto conformance = subs.lookupConformance(
reqt.TypeParameter->getCanonicalType(), reqt.Protocol);
externalSubArgs.push_back(
emitWitnessTableGeneratorForKeyPath(IGM, substType,
*conformance,
genericEnv, requirements));
}
});
}
fields.addInt32(
KeyPathComponentHeader::forExternalComponent(externalSubArgs.size())
.getData());
auto descriptor = IGM.getAddrOfLLVMVariableOrGOTEquivalent(
LinkEntity::forPropertyDescriptor(externalDecl));
fields.addRelativeAddress(descriptor);
for (auto *arg : externalSubArgs)
fields.addRelativeAddress(arg);
}
// 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;
KeyPathComponentHeader::ComputedPropertyIDResolution idResolution;
switch (id.getKind()) {
case KeyPathPatternComponent::ComputedPropertyId::Function: {
idKind = KeyPathComponentHeader::Pointer;
auto idRef = IGM.getAddrOfLLVMVariableOrGOTEquivalent(
LinkEntity::forSILFunction(id.getFunction(), false));
idValue = idRef.getValue();
// If we got an indirect reference, we'll need to resolve it at
// instantiation time.
idResolution = idRef.isIndirect()
? KeyPathComponentHeader::IndirectPointer
: KeyPathComponentHeader::Resolved;
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;
// FIXME: In non-JIT mode, ideally we would just refer to the selector
// reference variable here with an indirectpointer resolution,
// but ld64 section coalescing on the __objc_sel section can break
// relative references (and on some platforms, mach-o just doesn't
// support the necessary relocations).
// As a workaround, generate a stub function to resolve the selector.
//
// Note that we'd need to do this anyway in JIT mode because we would
// need to unique the selector at runtime anyway.
auto selectorName = IGM.getObjCSelectorName(declRef);
llvm::Type *fnParams[] = {IGM.Int8PtrTy};
auto fnTy = llvm::FunctionType::get(IGM.Int8PtrTy, fnParams, false);
SmallString<32> fnName;
fnName.append("keypath_get_selector_");
fnName.append(selectorName);
auto fn = cast<llvm::Function>(
IGM.Module.getOrInsertFunction(fnName, fnTy));
if (fn->empty()) {
fn->setLinkage(llvm::Function::PrivateLinkage);
IRGenFunction subIGF(IGM, fn);
if (IGM.DebugInfo)
IGM.DebugInfo->emitArtificialFunction(subIGF, fn);
auto selectorValue = subIGF.emitObjCSelectorRefLoad(selectorName);
subIGF.Builder.CreateRet(selectorValue);
}
idValue = fn;
idResolution = KeyPathComponentHeader::FunctionCall;
} else {
if (auto overridden = declRef.getOverriddenVTableEntry())
declRef = overridden;
if (auto overridden = declRef.getOverriddenWitnessTableEntry())
declRef = overridden;
auto dc = declRef.getDecl()->getDeclContext();
// We can use a method descriptor if we have a class or resilient
// protocol.
if (isa<ClassDecl>(dc) ||
IGM.isResilient(cast<NominalTypeDecl>(dc),
ResilienceExpansion::Minimal)) {
idKind = KeyPathComponentHeader::Pointer;
auto idRef = IGM.getAddrOfLLVMVariableOrGOTEquivalent(
LinkEntity::forMethodDescriptor(declRef));
idValue = idRef.getValue();
idResolution = idRef.isIndirect()
? KeyPathComponentHeader::IndirectPointer
: KeyPathComponentHeader::Resolved;
break;
}
idKind = KeyPathComponentHeader::VTableOffset;
auto methodProto = cast<ProtocolDecl>(dc);
auto &protoInfo = IGM.getProtocolInfo(methodProto,
ProtocolInfoKind::Full);
auto index = protoInfo.getFunctionIndex(
cast<AbstractFunctionDecl>(declRef.getDecl()));
idValue = llvm::ConstantInt::get(IGM.SizeTy, -index.getValue());
idResolution = KeyPathComponentHeader::Resolved;
}
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.
idResolution = KeyPathComponentHeader::Resolved;
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 (auto *classDecl = 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:
idResolution = KeyPathComponentHeader::Resolved;
idValue = llvm::ConstantInt::get(IGM.SizeTy,
getClassFieldIndex(classDecl, property));
break;
}
} else {
llvm_unreachable("neither struct nor class");
}
break;
}
auto header = KeyPathComponentHeader::forComputedProperty(componentKind,
idKind, !isInstantiableOnce, idResolution);
fields.addInt32(header.getData());
switch (idKind) {
case KeyPathComponentHeader::Pointer:
// Use a relative offset to the referent.
fields.addRelativeAddress(idValue);
break;
case KeyPathComponentHeader::VTableOffset:
case KeyPathComponentHeader::StoredPropertyIndex:
// Store the offset as an i32.
fields.add(llvm::ConstantExpr::getTruncOrBitCast(idValue, IGM.Int32Ty));
break;
}
// Push the accessors, possibly thunked to marshal generic environment.
fields.addRelativeAddress(
getAccessorForComputedComponent(IGM, component, Getter,
genericEnv, requirements,
hasSubscriptIndices));
if (settable)
fields.addRelativeAddress(
getAccessorForComputedComponent(IGM, component, Setter,
genericEnv, requirements,
hasSubscriptIndices));
if (!isInstantiableOnce) {
// 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.
fields.addRelativeAddress(
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 (auto witnessTable =
getWitnessTableForComputedComponent(IGM, component,
genericEnv, requirements)) {
fields.addRelativeAddress(witnessTable);
} else {
// If there are only generic parameters, we can use a prefab witness
// table from the runtime. Leaving a null reference here will let
// the runtime fill it in.
fields.addInt32(0);
}
// Add an initializer function that copies generic arguments out of the
// pattern argument buffer into the instantiated object.
fields.addRelativeAddress(
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 isInstantiableOnce = 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);
// If the pattern has no parameterization, add a pointer to a cache variable
// that can be used for the one-time initialization of the key path.
if (isInstantiableOnce) {
auto onceVar = new llvm::GlobalVariable(Module, OnceTy,
/*constant*/ false,
llvm::GlobalValue::PrivateLinkage,
llvm::ConstantInt::get(OnceTy, 0),
"keypath_once");
onceVar->setAlignment(getPointerAlignment().getValue());
fields.addRelativeAddress(onceVar);
} else {
fields.addInt32(0);
}
// Add the generic environment.
fields.addRelativeAddressOrNull(
getAddrOfGenericEnvironment(pattern->getGenericSignature()));
// Store type references for the root and leaf.
fields.addRelativeAddress(
emitMetadataGeneratorForKeyPath(*this, rootTy, genericEnv, requirements));
fields.addRelativeAddress(
emitMetadataGeneratorForKeyPath(*this, valueTy, genericEnv, requirements));
// Add a pointer to the ObjC KVC compatibility string, if there is one, or
// null otherwise.
if (!pattern->getObjCString().empty()) {
auto objcString = getAddrOfGlobalString(pattern->getObjCString(),
/*relatively addressed*/ true);
fields.addRelativeAddress(objcString);
} else {
fields.addInt32(0);
}
// 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);
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:
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, isInstantiableOnce,
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.addRelativeAddress(
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(), isInstantiableOnce,
/*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);
setTrueConstGlobal(patternVar);
KeyPathPatterns.insert({pattern, patternVar});
return patternVar;
}
void IRGenModule::emitSILProperty(SILProperty *prop) {
if (prop->isTrivial()) {
++NumTrivialPropertyDescriptors;
// All trivial property descriptors can share a single definition in the
// translation unit.
if (!TheTrivialPropertyDescriptor) {
// Emit a definition if we don't have one yet.
ConstantInitBuilder builder(*this);
ConstantStructBuilder fields = builder.beginStruct();
fields.addInt32(
_SwiftKeyPathComponentHeader_TrivialPropertyDescriptorMarker);
auto var = cast<llvm::GlobalVariable>(
getAddrOfPropertyDescriptor(prop->getDecl(),
fields.finishAndCreateFuture()));
var->setConstant(true);
var->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
var->setAlignment(4);
TheTrivialPropertyDescriptor = var;
} else {
auto entity = LinkEntity::forPropertyDescriptor(prop->getDecl());
auto linkInfo = LinkInfo::get(*this, entity, ForDefinition);
llvm::GlobalAlias::create(linkInfo.getLinkage(),
linkInfo.getName(),
TheTrivialPropertyDescriptor);
}
return;
}
++NumNonTrivialPropertyDescriptors;
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 var = cast<llvm::GlobalVariable>(
getAddrOfPropertyDescriptor(prop->getDecl(),
fields.finishAndCreateFuture()));
var->setConstant(true);
var->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
var->setAlignment(4);
}