Files
swift-mirror/lib/IRGen/GenStruct.cpp
Jordan Rose e05c03d5bc Standardize terminology for "computed", "stored", "variable", and "property".
These are the terms sent out in the proposal last week and described in
StoredAndComputedVariables.rst.

variable
  anything declared with 'var'
member variable
  a variable inside a nominal type (may be an instance variable or not)
property
  another term for "member variable"
computed variable
  a variable with a custom getter or setter
stored variable
  a variable with backing storage; any non-computed variable

These terms pre-exist in SIL and IRGen, so I only attempted to solidify
their definitions. Other than the use of "field" for "tuple element",
none of these should be exposed to users.

field
  a tuple element, or
  the underlying storage for a stored variable in a struct or class
physical
  describes an entity whose value can be accessed directly
logical
  describes an entity whose value must be accessed through some accessor

Swift SVN r8698
2013-09-26 18:50:44 +00:00

329 lines
12 KiB
C++

//===--- GenStruct.cpp - Swift IR Generation For 'struct' Types -----------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements IR generation for struct types.
//
//===----------------------------------------------------------------------===//
#include "GenStruct.h"
#include "swift/AST/Types.h"
#include "swift/AST/Decl.h"
#include "swift/AST/Pattern.h"
#include "swift/Basic/Optional.h"
#include "swift/IRGen/Options.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "GenMeta.h"
#include "GenSequential.h"
#include "GenType.h"
#include "IRGenFunction.h"
#include "IRGenModule.h"
#include "Linking.h"
#include "IndirectTypeInfo.h"
#include "NonFixedTypeInfo.h"
using namespace swift;
using namespace irgen;
namespace {
class StructFieldInfo : public SequentialField<StructFieldInfo> {
public:
StructFieldInfo(VarDecl *field, const TypeInfo &type)
: SequentialField(type), Field(field) {}
/// The field.
VarDecl *Field;
StringRef getFieldName() const {
return Field->getName().str();
}
};
/// A common base class for structs.
template <class Impl, class Base>
class StructTypeInfoBase :
public SequentialTypeInfo<Impl, Base, StructFieldInfo> {
typedef SequentialTypeInfo<Impl, Base, StructFieldInfo> super;
protected:
template <class... As>
StructTypeInfoBase(As &&...args) : super(std::forward<As>(args)...) {}
using super::asImpl;
public:
const StructFieldInfo &getFieldInfo(VarDecl *field) const {
// FIXME: cache the physical field index in the VarDecl.
for (auto &fieldInfo : asImpl().getFields()) {
if (fieldInfo.Field == field)
return fieldInfo;
}
llvm_unreachable("field not in struct?");
}
/// Given a full struct explosion, project out a single field.
void projectFieldFromExplosion(IRGenFunction &IGF,
Explosion &in,
VarDecl *field,
Explosion &out) const {
assert(in.getKind() == out.getKind());
auto &fieldInfo = getFieldInfo(field);
// If the field requires no storage, there's nothing to do.
if (fieldInfo.isEmpty())
return;
// Otherwise, project from the base.
auto fieldRange = fieldInfo.getProjectionRange(out.getKind());
auto elements = in.getRange(fieldRange.first, fieldRange.second);
out.add(elements);
}
/// Given the address of a tuple, project out the address of a
/// single element.
Address projectFieldAddress(IRGenFunction &IGF,
Address addr,
VarDecl *field) const {
auto &fieldInfo = getFieldInfo(field);
if (fieldInfo.isEmpty())
return fieldInfo.getTypeInfo().getUndefAddress();
auto offsets = asImpl().getNonFixedOffsets(IGF);
return fieldInfo.projectAddress(IGF, addr, offsets);
}
};
/// A type implementation for loadable struct types.
class LoadableStructTypeInfo
: public StructTypeInfoBase<LoadableStructTypeInfo, LoadableTypeInfo> {
public:
// FIXME: Spare bits between struct members.
LoadableStructTypeInfo(unsigned numFields, llvm::Type *T, Size size,
Alignment align, IsPOD_t isPOD)
: StructTypeInfoBase(numFields, T, size, llvm::BitVector{}, align, isPOD)
{}
bool isIndirectArgument(ExplosionKind kind) const override { return false; }
void initializeFromParams(IRGenFunction &IGF, Explosion &params,
Address addr) const override {
LoadableStructTypeInfo::initialize(IGF, params, addr);
}
Nothing_t getNonFixedOffsets(IRGenFunction &IGF) const { return Nothing; }
};
/// A type implementation for non-loadable but fixed-size struct types.
class FixedStructTypeInfo
: public StructTypeInfoBase<FixedStructTypeInfo,
IndirectTypeInfo<FixedStructTypeInfo,
FixedTypeInfo>> {
public:
// FIXME: Spare bits between struct members.
FixedStructTypeInfo(unsigned numFields, llvm::Type *T, Size size,
Alignment align, IsPOD_t isPOD)
: StructTypeInfoBase(numFields, T, size, llvm::BitVector{}, align, isPOD)
{}
Nothing_t getNonFixedOffsets(IRGenFunction &IGF) const { return Nothing; }
};
/// A type implementation for non-fixed struct types.
class NonFixedStructTypeInfo
: public StructTypeInfoBase<NonFixedStructTypeInfo,
WitnessSizedTypeInfo<NonFixedStructTypeInfo>> {
CanType TheType;
public:
NonFixedStructTypeInfo(unsigned numFields, llvm::Type *T, CanType theType,
Alignment align, IsPOD_t isPOD)
: StructTypeInfoBase(numFields, T, align, isPOD), TheType(theType) {
}
// FIXME: implement
Nothing_t getNonFixedOffsets(IRGenFunction &IGF) const { return Nothing; }
llvm::Value *getMetadataRef(IRGenFunction &IGF) const {
return IGF.emitTypeMetadataRef(TheType);
}
llvm::Value *getValueWitnessTable(IRGenFunction &IGF) const {
auto metadata = getMetadataRef(IGF);
return IGF.emitValueWitnessTableRefForMetadata(metadata);
}
void initializeValueWitnessTable(IRGenFunction &IGF,
llvm::Value *metadata,
llvm::Value *vwtable) const override {
// FIXME
}
};
class StructTypeBuilder :
public SequentialTypeBuilder<StructTypeBuilder, StructFieldInfo, VarDecl*> {
llvm::StructType *StructTy;
CanType TheStruct;
public:
StructTypeBuilder(IRGenModule &IGM, llvm::StructType *structTy,
CanType type) :
SequentialTypeBuilder(IGM), StructTy(structTy), TheStruct(type) {
}
LoadableStructTypeInfo *createLoadable(ArrayRef<StructFieldInfo> fields,
const StructLayout &layout) {
return create<LoadableStructTypeInfo>(fields, layout.getType(),
layout.getSize(),
layout.getAlignment(),
layout.isKnownPOD());
}
FixedStructTypeInfo *createFixed(ArrayRef<StructFieldInfo> fields,
const StructLayout &layout) {
return create<FixedStructTypeInfo>(fields, layout.getType(),
layout.getSize(),
layout.getAlignment(),
layout.isKnownPOD());
}
NonFixedStructTypeInfo *createNonFixed(ArrayRef<StructFieldInfo> fields,
const StructLayout &layout) {
return create<NonFixedStructTypeInfo>(fields, layout.getType(),
TheStruct,
layout.getAlignment(),
layout.isKnownPOD());
}
StructFieldInfo getFieldInfo(VarDecl *field, const TypeInfo &fieldTI) {
return StructFieldInfo(field, fieldTI);
}
Type getType(VarDecl *field) { return field->getType(); }
StructLayout performLayout(ArrayRef<const TypeInfo *> fieldTypes) {
return StructLayout(IGM, LayoutKind::NonHeapObject,
LayoutStrategy::Optimal, fieldTypes, StructTy);
}
};
} // end anonymous namespace.
/// A convenient macro for delegating an operation to all of the
/// various struct implementations.
#define FOR_STRUCT_IMPL(IGF, type, op, ...) do { \
auto &structTI = IGF.getTypeInfo(type); \
if (isa<LoadableStructTypeInfo>(structTI)) { \
return structTI.as<LoadableStructTypeInfo>().op(IGF, __VA_ARGS__); \
} else if (isa<FixedTypeInfo>(structTI)) { \
return structTI.as<FixedStructTypeInfo>().op(IGF, __VA_ARGS__); \
} else { \
return structTI.as<NonFixedStructTypeInfo>().op(IGF, __VA_ARGS__); \
} \
} while(0)
Address irgen::projectPhysicalStructMemberAddress(IRGenFunction &IGF,
Address base,
SILType baseType,
VarDecl *field) {
FOR_STRUCT_IMPL(IGF, baseType, projectFieldAddress, base, field);
}
void irgen::projectPhysicalStructMemberFromExplosion(IRGenFunction &IGF,
SILType baseType,
Explosion &base,
VarDecl *field,
Explosion &out) {
FOR_STRUCT_IMPL(IGF, baseType, projectFieldFromExplosion, base, field, out);
}
/// emitStructDecl - Emit all the declarations associated with this struct type.
void IRGenModule::emitStructDecl(StructDecl *st) {
emitStructMetadata(*this, st);
// FIXME: This is mostly copy-paste from emitExtension;
// figure out how to refactor!
for (Decl *member : st->getMembers()) {
switch (member->getKind()) {
case DeclKind::Import:
case DeclKind::TopLevelCode:
case DeclKind::Protocol:
case DeclKind::Extension:
case DeclKind::Destructor:
case DeclKind::EnumCase:
case DeclKind::EnumElement:
case DeclKind::InfixOperator:
case DeclKind::PrefixOperator:
case DeclKind::PostfixOperator:
llvm_unreachable("decl not allowed in struct!");
// We can have meaningful initializers for variables, but
// we can't handle them yet. For the moment, just ignore them.
case DeclKind::PatternBinding:
continue;
case DeclKind::Subscript:
// Getter/setter will be handled separately.
continue;
case DeclKind::TypeAlias:
case DeclKind::AssociatedType:
case DeclKind::GenericTypeParam:
continue;
case DeclKind::Enum:
emitEnumDecl(cast<EnumDecl>(member));
continue;
case DeclKind::Struct:
emitStructDecl(cast<StructDecl>(member));
continue;
case DeclKind::Class:
emitClassDecl(cast<ClassDecl>(member));
continue;
case DeclKind::Var:
if (cast<VarDecl>(member)->isComputed())
// 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");
}
}
const TypeInfo *TypeConverter::convertStructType(CanType type, StructDecl *D) {
// Collect all the fields from the type.
SmallVector<VarDecl*, 8> fields;
for (Decl *D : D->getMembers())
if (VarDecl *VD = dyn_cast<VarDecl>(D))
if (!VD->isComputed()) {
if (!IGM.Opts.EnableDynamicValueTypeLayout &&
!IGM.getTypeInfo(VD->getType()).isFixedSize()) {
IGM.unimplemented(VD->getLoc(), "dynamic field layout in structs");
exit(1);
}
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(type.getPointer(), ty);
// Build the type.
StructTypeBuilder builder(IGM, ty, type);
return builder.layout(fields);
}