mirror of
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c57dac63ae
for extra inhabitants. For structs in particular, this eliminates a major source of abstraction penatlies. For example, an optional struct containing an object pointer is now represented the same way as an optional object pointer, which is critical for correctly importing CF types as Unmanaged<T>!. In time, we should generalize this to consider all elements as sources for extra inhabitants, as well as exploiting spare bits in the representation, but getting the single-element case right really provides the bulk of the benefit. This commit restores r17242 and r17243 with a fix to use value witnesses that actually forward the right type metadata down. We were already generating these value witnesses in the dependent struct VWT pattern, but I was being too clever and trying to use the underlying value witness directly. Swift SVN r17267
525 lines
21 KiB
C++
525 lines
21 KiB
C++
//===--- GenStruct.cpp - Swift IR Generation For 'struct' Types -----------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements IR generation for struct types.
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//
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//===----------------------------------------------------------------------===//
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#include "GenStruct.h"
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#include "swift/AST/Types.h"
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#include "swift/AST/Decl.h"
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#include "swift/AST/IRGenOptions.h"
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#include "swift/AST/Pattern.h"
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#include "swift/Basic/Optional.h"
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#include "swift/SIL/SILModule.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/Function.h"
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#include "GenMeta.h"
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#include "GenSequential.h"
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#include "GenType.h"
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#include "IRGenFunction.h"
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#include "IRGenModule.h"
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#include "Linking.h"
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#include "IndirectTypeInfo.h"
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#include "NonFixedTypeInfo.h"
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#include "StructMetadataLayout.h"
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using namespace swift;
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using namespace irgen;
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namespace {
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class StructFieldInfo : public SequentialField<StructFieldInfo> {
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public:
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StructFieldInfo(VarDecl *field, const TypeInfo &type)
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: SequentialField(type), Field(field) {}
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/// The field.
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VarDecl * const Field;
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StringRef getFieldName() const {
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return Field->getName().str();
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}
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CanType getType(IRGenModule &IGM, CanType T) const {
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return T->getTypeOfMember(IGM.SILMod->getSwiftModule(),
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Field, nullptr)
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->getCanonicalType();
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}
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};
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/// A common base class for structs.
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template <class Impl, class Base>
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class StructTypeInfoBase :
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public SequentialTypeInfo<Impl, Base, StructFieldInfo> {
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typedef SequentialTypeInfo<Impl, Base, StructFieldInfo> super;
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protected:
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template <class... As>
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StructTypeInfoBase(As &&...args) : super(std::forward<As>(args)...) {}
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using super::asImpl;
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public:
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const StructFieldInfo &getFieldInfo(VarDecl *field) const {
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// FIXME: cache the physical field index in the VarDecl.
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for (auto &fieldInfo : asImpl().getFields()) {
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if (fieldInfo.Field == field)
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return fieldInfo;
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}
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llvm_unreachable("field not in struct?");
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}
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/// Given a full struct explosion, project out a single field.
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void projectFieldFromExplosion(IRGenFunction &IGF,
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Explosion &in,
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VarDecl *field,
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Explosion &out) const {
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assert(in.getKind() == out.getKind());
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auto &fieldInfo = getFieldInfo(field);
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// If the field requires no storage, there's nothing to do.
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if (fieldInfo.isEmpty())
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return;
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// Otherwise, project from the base.
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auto fieldRange = fieldInfo.getProjectionRange(out.getKind());
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auto elements = in.getRange(fieldRange.first, fieldRange.second);
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out.add(elements);
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}
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/// Given the address of a tuple, project out the address of a
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/// single element.
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Address projectFieldAddress(IRGenFunction &IGF,
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Address addr,
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CanType T,
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VarDecl *field) const {
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const StructFieldInfo &fieldInfo = getFieldInfo(field);
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if (fieldInfo.isEmpty())
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return fieldInfo.getTypeInfo().getUndefAddress();
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auto offsets = asImpl().getNonFixedOffsets(IGF, T);
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return fieldInfo.projectAddress(IGF, addr, offsets);
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}
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/// Return the constant offset of a field as a SizeTy, or nullptr if the
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/// field is not at a fixed offset.
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llvm::Constant *getConstantFieldOffset(IRGenModule &IGM,
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VarDecl *field) const {
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const StructFieldInfo &fieldInfo = getFieldInfo(field);
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if (fieldInfo.getKind() == ElementLayout::Kind::Fixed) {
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return llvm::ConstantInt::get(IGM.SizeTy,
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fieldInfo.getFixedByteOffset().getValue());
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}
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return nullptr;
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}
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// For now, just use extra inhabitants from the first field.
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// FIXME: generalize
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bool mayHaveExtraInhabitants(IRGenModule &IGM) const override {
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if (asImpl().getFields().empty()) return false;
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return asImpl().getFields()[0].getTypeInfo().mayHaveExtraInhabitants(IGM);
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}
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// This is dead code in NonFixedStructTypeInfo.
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unsigned getFixedExtraInhabitantCount(IRGenModule &IGM) const {
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if (asImpl().getFields().empty()) return 0;
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auto &fieldTI = cast<FixedTypeInfo>(asImpl().getFields()[0].getTypeInfo());
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return fieldTI.getFixedExtraInhabitantCount(IGM);
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}
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// This is dead code in NonFixedStructTypeInfo.
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llvm::ConstantInt *getFixedExtraInhabitantValue(IRGenModule &IGM,
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unsigned bits,
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unsigned index) const {
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auto &fieldTI = cast<FixedTypeInfo>(asImpl().getFields()[0].getTypeInfo());
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return fieldTI.getFixedExtraInhabitantValue(IGM, bits, index);
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}
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// This is dead code in NonFixedStructTypeInfo.
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llvm::Value *maskFixedExtraInhabitant(IRGenFunction &IGF,
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llvm::Value *structValue) const {
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// Truncate down to the width of the field, mask it recursively,
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// and then zext back out to the payload size.
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auto &fieldTI = cast<FixedTypeInfo>(asImpl().getFields()[0].getTypeInfo());
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unsigned fieldWidth = fieldTI.getFixedSize().getValueInBits();
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auto fieldTy = llvm::IntegerType::get(IGF.IGM.getLLVMContext(), fieldWidth);
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auto fieldValue = IGF.Builder.CreateTrunc(structValue, fieldTy);
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fieldValue = fieldTI.maskFixedExtraInhabitant(IGF, fieldValue);
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return IGF.Builder.CreateZExt(fieldValue, structValue->getType());
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}
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llvm::Value *getExtraInhabitantIndex(IRGenFunction &IGF,
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Address structAddr,
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CanType structType) const override {
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auto &field = asImpl().getFields()[0];
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Address fieldAddr =
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asImpl().projectFieldAddress(IGF, structAddr, structType, field.Field);
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return field.getTypeInfo().getExtraInhabitantIndex(IGF, fieldAddr,
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field.getType(IGF.IGM, structType));
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}
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void storeExtraInhabitant(IRGenFunction &IGF,
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llvm::Value *index,
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Address structAddr,
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CanType structType) const override {
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auto &field = asImpl().getFields()[0];
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Address fieldAddr =
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asImpl().projectFieldAddress(IGF, structAddr, structType, field.Field);
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field.getTypeInfo().storeExtraInhabitant(IGF, index, fieldAddr,
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field.getType(IGF.IGM, structType));
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}
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};
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/// A type implementation for loadable struct types.
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class LoadableStructTypeInfo
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: public StructTypeInfoBase<LoadableStructTypeInfo, LoadableTypeInfo> {
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public:
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// FIXME: Spare bits between struct members.
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LoadableStructTypeInfo(unsigned numFields, llvm::Type *T, Size size,
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llvm::BitVector spareBits,
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Alignment align, IsPOD_t isPOD)
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: StructTypeInfoBase(numFields, T, size, std::move(spareBits),
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align, isPOD)
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{}
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bool isIndirectArgument(ResilienceExpansion kind) const override { return false; }
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void initializeFromParams(IRGenFunction &IGF, Explosion ¶ms,
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Address addr, CanType T) const override {
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LoadableStructTypeInfo::initialize(IGF, params, addr);
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}
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Nothing_t getNonFixedOffsets(IRGenFunction &IGF, CanType T) const {
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return Nothing;
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}
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Nothing_t getNonFixedOffsets(IRGenFunction &IGF) const {
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return Nothing;
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}
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};
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/// A type implementation for non-loadable but fixed-size struct types.
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class FixedStructTypeInfo
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: public StructTypeInfoBase<FixedStructTypeInfo,
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IndirectTypeInfo<FixedStructTypeInfo,
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FixedTypeInfo>> {
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public:
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// FIXME: Spare bits between struct members.
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FixedStructTypeInfo(unsigned numFields, llvm::Type *T, Size size,
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llvm::BitVector spareBits,
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Alignment align, IsPOD_t isPOD, IsBitwiseTakable_t isBT)
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: StructTypeInfoBase(numFields, T, size, std::move(spareBits), align,
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isPOD, isBT)
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{}
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Nothing_t getNonFixedOffsets(IRGenFunction &IGF, CanType T) const {
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return Nothing;
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}
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Nothing_t getNonFixedOffsets(IRGenFunction &IGF) const { return Nothing; }
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};
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/// Find the beginning of the field offset vector in a struct's metadata.
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static Address
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emitAddressOfFieldOffsetVector(IRGenFunction &IGF,
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StructDecl *S,
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llvm::Value *metadata) {
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struct GetStartOfFieldOffsets
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: StructMetadataScanner<GetStartOfFieldOffsets>
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{
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GetStartOfFieldOffsets(IRGenModule &IGM, StructDecl *target)
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: StructMetadataScanner(IGM, target) {}
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Size StartOfFieldOffsets = Size::invalid();
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void noteAddressPoint() {
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assert(StartOfFieldOffsets == Size::invalid()
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&& "found field offsets before address point?");
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NextOffset = Size(0);
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}
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void noteStartOfFieldOffsets() { StartOfFieldOffsets = NextOffset; }
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};
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// Find where the field offsets begin.
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GetStartOfFieldOffsets scanner(IGF.IGM, S);
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scanner.layout();
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assert(scanner.StartOfFieldOffsets != Size::invalid()
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&& "did not find start of field offsets?!");
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Size StartOfFieldOffsets = scanner.StartOfFieldOffsets;
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// Find that offset into the metadata.
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llvm::Value *fieldVector
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= IGF.Builder.CreateBitCast(metadata, IGF.IGM.SizeTy->getPointerTo());
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return IGF.Builder.CreateConstArrayGEP(
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Address(fieldVector, IGF.IGM.getPointerAlignment()),
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StartOfFieldOffsets / IGF.IGM.getPointerSize(),
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StartOfFieldOffsets);
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}
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/// Accessor for the non-fixed offsets of a struct type.
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class StructNonFixedOffsets : public NonFixedOffsetsImpl {
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CanType TheStruct;
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public:
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StructNonFixedOffsets(CanType type) : TheStruct(type) {
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assert(TheStruct->getStructOrBoundGenericStruct());
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}
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llvm::Value *getOffsetForIndex(IRGenFunction &IGF, unsigned index) {
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// Get the field offset vector from the struct metadata.
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llvm::Value *metadata = IGF.emitTypeMetadataRef(TheStruct);
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Address fieldVector = emitAddressOfFieldOffsetVector(IGF,
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TheStruct->getStructOrBoundGenericStruct(),
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metadata);
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// Grab the indexed offset.
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fieldVector = IGF.Builder.CreateConstArrayGEP(fieldVector, index,
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IGF.IGM.getPointerSize());
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return IGF.Builder.CreateLoad(fieldVector);
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}
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};
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/// A type implementation for non-fixed struct types.
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class NonFixedStructTypeInfo
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: public StructTypeInfoBase<NonFixedStructTypeInfo,
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WitnessSizedTypeInfo<NonFixedStructTypeInfo>>
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{
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public:
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NonFixedStructTypeInfo(unsigned numFields, llvm::Type *T,
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Alignment align,
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IsPOD_t isPOD, IsBitwiseTakable_t isBT)
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: StructTypeInfoBase(numFields, T, align, isPOD, isBT) {
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}
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// We have an indirect schema.
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void getSchema(ExplosionSchema &s) const override {
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s.add(ExplosionSchema::Element::forAggregate(getStorageType(),
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getBestKnownAlignment()));
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}
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StructNonFixedOffsets
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getNonFixedOffsets(IRGenFunction &IGF, CanType T) const {
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return StructNonFixedOffsets(T);
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}
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void initializeMetadata(IRGenFunction &IGF,
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llvm::Value *metadata,
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llvm::Value *vwtable,
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CanType T) const override {
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// Get the field offset vector.
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llvm::Value *fieldVector = emitAddressOfFieldOffsetVector(IGF,
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T->getStructOrBoundGenericStruct(),
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metadata).getAddress();
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// Collect the stored properties of the type.
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llvm::SmallVector<VarDecl*, 4> storedProperties;
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for (auto prop : T->getStructOrBoundGenericStruct()
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->getStoredProperties()) {
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storedProperties.push_back(prop);
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}
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// Fill out an array with the field type metadata records.
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Address fields = IGF.createAlloca(
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llvm::ArrayType::get(IGF.IGM.TypeMetadataPtrTy,
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storedProperties.size()),
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IGF.IGM.getPointerAlignment(), "structFields");
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fields = IGF.Builder.CreateBitCast(fields,
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IGF.IGM.TypeMetadataPtrTy->getPointerTo());
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unsigned index = 0;
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for (auto prop : storedProperties) {
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llvm::Value *metadata = IGF.emitTypeMetadataRef(
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prop->getType()->getCanonicalType());
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Address field = IGF.Builder.CreateConstArrayGEP(fields, index,
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IGF.IGM.getPointerSize());
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IGF.Builder.CreateStore(metadata, field);
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++index;
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}
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// Ask the runtime to lay out the struct.
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auto numFields = llvm::ConstantInt::get(IGF.IGM.SizeTy,
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storedProperties.size());
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IGF.Builder.CreateCall4(IGF.IGM.getInitStructMetadataUniversalFn(),
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numFields, fields.getAddress(),
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fieldVector, vwtable);
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}
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};
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class StructTypeBuilder :
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public SequentialTypeBuilder<StructTypeBuilder, StructFieldInfo, VarDecl*> {
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llvm::StructType *StructTy;
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CanType TheStruct;
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public:
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StructTypeBuilder(IRGenModule &IGM, llvm::StructType *structTy,
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CanType type) :
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SequentialTypeBuilder(IGM), StructTy(structTy), TheStruct(type) {
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}
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LoadableStructTypeInfo *createLoadable(ArrayRef<StructFieldInfo> fields,
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const StructLayout &layout) {
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return create<LoadableStructTypeInfo>(fields, layout.getType(),
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layout.getSize(),
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layout.getSpareBits(),
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layout.getAlignment(),
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layout.isKnownPOD());
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}
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FixedStructTypeInfo *createFixed(ArrayRef<StructFieldInfo> fields,
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const StructLayout &layout) {
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return create<FixedStructTypeInfo>(fields, layout.getType(),
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layout.getSize(),
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layout.getSpareBits(),
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layout.getAlignment(),
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layout.isKnownPOD(),
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layout.isKnownBitwiseTakable());
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}
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NonFixedStructTypeInfo *createNonFixed(ArrayRef<StructFieldInfo> fields,
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const StructLayout &layout) {
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return create<NonFixedStructTypeInfo>(fields, layout.getType(),
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layout.getAlignment(),
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layout.isKnownPOD(),
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layout.isKnownBitwiseTakable());
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}
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StructFieldInfo getFieldInfo(unsigned index,
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VarDecl *field, const TypeInfo &fieldTI) {
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return StructFieldInfo(field, fieldTI);
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}
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SILType getType(VarDecl *field) {
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assert(field->getDeclContext() == TheStruct->getAnyNominal());
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auto silType = SILType::getPrimitiveAddressType(TheStruct);
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return silType.getFieldType(field, *IGM.SILMod);
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}
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StructLayout performLayout(ArrayRef<const TypeInfo *> fieldTypes) {
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return StructLayout(IGM, LayoutKind::NonHeapObject,
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LayoutStrategy::Optimal, fieldTypes, StructTy);
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}
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};
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} // end anonymous namespace.
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/// A convenient macro for delegating an operation to all of the
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/// various struct implementations.
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#define FOR_STRUCT_IMPL(IGF, type, op, ...) do { \
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auto &structTI = IGF.getTypeInfo(type); \
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if (isa<LoadableStructTypeInfo>(structTI)) { \
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return structTI.as<LoadableStructTypeInfo>().op(IGF, __VA_ARGS__); \
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} else if (isa<FixedTypeInfo>(structTI)) { \
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return structTI.as<FixedStructTypeInfo>().op(IGF, __VA_ARGS__); \
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} else { \
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return structTI.as<NonFixedStructTypeInfo>().op(IGF, __VA_ARGS__); \
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} \
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} while(0)
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Address irgen::projectPhysicalStructMemberAddress(IRGenFunction &IGF,
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Address base,
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SILType baseType,
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VarDecl *field) {
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FOR_STRUCT_IMPL(IGF, baseType, projectFieldAddress, base,
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baseType.getSwiftRValueType(), field);
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}
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void irgen::projectPhysicalStructMemberFromExplosion(IRGenFunction &IGF,
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SILType baseType,
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Explosion &base,
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VarDecl *field,
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Explosion &out) {
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FOR_STRUCT_IMPL(IGF, baseType, projectFieldFromExplosion, base, field, out);
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}
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llvm::Constant *irgen::emitPhysicalStructMemberFixedOffset(IRGenModule &IGM,
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SILType baseType,
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VarDecl *field) {
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FOR_STRUCT_IMPL(IGM, baseType, getConstantFieldOffset, field);
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}
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/// emitStructDecl - Emit all the declarations associated with this struct type.
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void IRGenModule::emitStructDecl(StructDecl *st) {
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emitStructMetadata(*this, st);
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// FIXME: This is mostly copy-paste from emitExtension;
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// figure out how to refactor!
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for (Decl *member : st->getMembers()) {
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switch (member->getKind()) {
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case DeclKind::Import:
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case DeclKind::TopLevelCode:
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case DeclKind::Protocol:
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case DeclKind::Extension:
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case DeclKind::Destructor:
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case DeclKind::EnumCase:
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case DeclKind::EnumElement:
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case DeclKind::InfixOperator:
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case DeclKind::PrefixOperator:
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case DeclKind::PostfixOperator:
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case DeclKind::Param:
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llvm_unreachable("decl not allowed in struct!");
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// We can have meaningful initializers for variables, but
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// we can't handle them yet. For the moment, just ignore them.
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case DeclKind::PatternBinding:
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continue;
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// Active members of the IfConfig block are handled separately.
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case DeclKind::IfConfig:
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continue;
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case DeclKind::Subscript:
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// Getter/setter will be handled separately.
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continue;
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case DeclKind::TypeAlias:
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case DeclKind::AssociatedType:
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case DeclKind::GenericTypeParam:
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continue;
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case DeclKind::Enum:
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emitEnumDecl(cast<EnumDecl>(member));
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continue;
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case DeclKind::Struct:
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emitStructDecl(cast<StructDecl>(member));
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continue;
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case DeclKind::Class:
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emitClassDecl(cast<ClassDecl>(member));
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continue;
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case DeclKind::Var:
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|
if (!cast<VarDecl>(member)->hasStorage())
|
|
// Getter/setter will be handled separately.
|
|
continue;
|
|
// FIXME: Will need an implementation here for resilience
|
|
continue;
|
|
case DeclKind::Func:
|
|
emitLocalDecls(cast<FuncDecl>(member));
|
|
continue;
|
|
case DeclKind::Constructor:
|
|
emitLocalDecls(cast<ConstructorDecl>(member));
|
|
continue;
|
|
}
|
|
llvm_unreachable("bad extension member kind");
|
|
}
|
|
}
|
|
#include "llvm/Support/raw_ostream.h"
|
|
|
|
const TypeInfo *TypeConverter::convertStructType(TypeBase *key, CanType type,
|
|
StructDecl *D) {
|
|
// Collect all the fields from the type.
|
|
SmallVector<VarDecl*, 8> fields;
|
|
for (VarDecl *VD : D->getStoredProperties())
|
|
fields.push_back(VD);
|
|
|
|
// Create the struct type.
|
|
auto ty = IGM.createNominalType(D);
|
|
|
|
// Register a forward declaration before we look at any of the child types.
|
|
addForwardDecl(key, ty);
|
|
|
|
// Build the type.
|
|
StructTypeBuilder builder(IGM, ty, type);
|
|
return builder.layout(fields);
|
|
}
|