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//===--- ExistentialMetadataImpl.h - Existential metadata -------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Declarations used to implement value witnesses for Swift
// existential types.
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_RUNTIME_EXISTENTIALMETADATAIMPL_H
#define SWIFT_RUNTIME_EXISTENTIALMETADATAIMPL_H
#include "MetadataImpl.h"
#include "swift/Runtime/ExistentialContainer.h"
namespace swift {
namespace metadataimpl {
/// A common base class for opaque-existential and class-existential boxes.
template <typename Impl> struct SWIFT_LIBRARY_VISIBILITY ExistentialBoxBase {};
/// A common base class for fixed and non-fixed opaque-existential box
/// implementations.
struct SWIFT_LIBRARY_VISIBILITY OpaqueExistentialBoxBase
: ExistentialBoxBase<OpaqueExistentialBoxBase> {
template <class Container, class... A>
static void destroy(Container *value, A... args) {
auto *type = value->getType();
auto *vwt = type->getValueWitnesses();
if (vwt->isValueInline()) {
// destroy(&valueBuffer)
type->vw_destroy(
reinterpret_cast<OpaqueValue *>(value->getBuffer(args...)));
} else {
// release(valueBuffer[0])
swift_release(
*reinterpret_cast<HeapObject **>(value->getBuffer(args...)));
}
}
enum class Dest {
Assign,
Init,
};
enum class Source {
Copy,
Take
};
template <class Container, class... A>
static void copyReference(Container *dest, Container *src, Dest d, Source s,
A... args) {
auto *destRefAddr =
reinterpret_cast<HeapObject **>(dest->getBuffer(args...));
// Load the source reference.
auto *srcRef = *reinterpret_cast<HeapObject **>(src->getBuffer(args...));
// Load the old destination reference so we can release it later if this is
// an assignment.
HeapObject *destRef = d == Dest::Assign ? *destRefAddr : nullptr;
// Do the assignment.
*destRefAddr = srcRef;
// If we copy the source retain the reference.
if (s == Source::Copy)
swift_retain(srcRef);
// If we have an assignment release the old reference.
if (d == Dest::Assign)
swift_release(destRef);
}
template <class Container, class... A>
static Container *initializeWithCopy(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
auto *type = src->getType();
auto *vwt = type->getValueWitnesses();
if (vwt->isValueInline()) {
auto *destValue =
reinterpret_cast<OpaqueValue *>(dest->getBuffer(args...));
auto *srcValue =
reinterpret_cast<OpaqueValue *>(src->getBuffer(args...));
type->vw_initializeWithCopy(destValue, srcValue);
} else {
// initWithCopy of the reference to the cow box.
copyReference(dest, src, Dest::Init, Source::Copy, args...);
}
return dest;
}
template <class Container, class... A>
static Container *initializeWithTake(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
auto from = src->getBuffer(args...);
auto to = dest->getBuffer(args...);
memcpy(to, from, sizeof(ValueBuffer));
return dest;
}
template <class Container, class... A>
static Container *assignWithCopy(Container *dest, Container *src,
A... args) {
auto srcType = src->getType();
auto destType = dest->getType();
if (src == dest)
return dest;
if (srcType == destType) {
// Types match.
auto *vwt = srcType->getValueWitnesses();
if (vwt->isValueInline()) {
// Inline.
auto *destValue =
reinterpret_cast<OpaqueValue *>(dest->getBuffer(args...));
auto *srcValue =
reinterpret_cast<OpaqueValue *>(src->getBuffer(args...));
// assignWithCopy.
srcType->vw_assignWithCopy(destValue, srcValue);
} else {
// Outline (boxed value).
// assignWithCopy.
copyReference(dest, src, Dest::Assign, Source::Copy, args...);
}
} else {
// Different types.
auto *destVwt = destType->getValueWitnesses();
auto *srcVwt = srcType->getValueWitnesses();
if (destVwt->isValueInline()) {
// Inline destination value.
ValueBuffer tmpBuffer;
auto *opaqueTmpBuffer = reinterpret_cast<OpaqueValue *>(&tmpBuffer);
auto *destValue =
reinterpret_cast<OpaqueValue *>(dest->getBuffer(args...));
auto *srcValue =
reinterpret_cast<OpaqueValue *>(src->getBuffer(args...));
// Move dest value aside so we can destroy it later.
destType->vw_initializeWithTake(opaqueTmpBuffer, destValue);
src->copyTypeInto(dest, args...);
if (srcVwt->isValueInline()) {
// Inline src value.
srcType->vw_initializeWithCopy(destValue, srcValue);
} else {
// Outline src value.
// initWithCopy of reference to cow box.
copyReference(dest, src, Dest::Init, Source::Copy, args...);
}
// Finally, destroy the old dest value.
destType->vw_destroy(opaqueTmpBuffer);
} else {
// Outline destination value.
// Get the dest reference so we can release it later.
auto *destRef =
*reinterpret_cast<HeapObject **>(dest->getBuffer(args...));
src->copyTypeInto(dest, args...);
if (srcVwt->isValueInline()) {
// initWithCopy.
auto *destValue =
reinterpret_cast<OpaqueValue *>(dest->getBuffer(args...));
auto *srcValue =
reinterpret_cast<OpaqueValue *>(src->getBuffer(args...));
srcType->vw_initializeWithCopy(destValue, srcValue);
} else {
// initWithCopy of reference to cow box.
copyReference(dest, src, Dest::Init, Source::Copy, args...);
}
// Release dest reference.
swift_release(destRef);
}
}
return dest;
}
template <class Container, class... A>
static Container *assignWithTake(Container *dest, Container *src,
A... args) {
auto srcType = src->getType();
auto destType = dest->getType();
if (src == dest)
return dest;
if (srcType == destType) {
// Types match.
auto *vwt = srcType->getValueWitnesses();
if (vwt->isValueInline()) {
// Inline.
auto *destValue =
reinterpret_cast<OpaqueValue *>(dest->getBuffer(args...));
auto *srcValue =
reinterpret_cast<OpaqueValue *>(src->getBuffer(args...));
// assignWithTake.
srcType->vw_assignWithTake(destValue, srcValue);
} else {
// Outline (boxed value).
// assignWithTake of reference to cow box.
copyReference(dest, src, Dest::Assign, Source::Take, args...);
}
} else {
// Different types.
auto *destVwt = destType->getValueWitnesses();
auto *srcVwt = srcType->getValueWitnesses();
if (destVwt->isValueInline()) {
// Inline destination value.
ValueBuffer tmpBuffer;
auto *opaqueTmpBuffer = reinterpret_cast<OpaqueValue *>(&tmpBuffer);
auto *destValue =
reinterpret_cast<OpaqueValue *>(dest->getBuffer(args...));
auto *srcValue =
reinterpret_cast<OpaqueValue *>(src->getBuffer(args...));
// Move dest value aside.
destType->vw_initializeWithTake(opaqueTmpBuffer, destValue);
src->copyTypeInto(dest, args...);
if (srcVwt->isValueInline()) {
// Inline src value.
srcType->vw_initializeWithTake(destValue, srcValue);
} else {
// Outline src value.
// initWithTake of reference to cow box.
copyReference(dest, src, Dest::Init, Source::Take, args...);
}
// Destroy old dest value.
destType->vw_destroy(opaqueTmpBuffer);
} else {
// Outline destination value.
// Get the old dest reference.
auto *destRef =
*reinterpret_cast<HeapObject **>(dest->getBuffer(args...));
src->copyTypeInto(dest, args...);
if (srcVwt->isValueInline()) {
// initWithCopy.
auto *destValue =
reinterpret_cast<OpaqueValue *>(dest->getBuffer(args...));
auto *srcValue =
reinterpret_cast<OpaqueValue *>(src->getBuffer(args...));
// initWithTake.
srcType->vw_initializeWithTake(destValue, srcValue);
} else {
// initWithTake of reference to cow box.
copyReference(dest, src, Dest::Init, Source::Take, args...);
}
// Release old dest reference.
swift_release(destRef);
}
}
return dest;
}
};
/// The basic layout of an opaque existential with a fixed number of
/// witness tables. Note that the WitnessTables field is accessed via
/// spooky action from Header.
template <unsigned NumWitnessTables>
struct SWIFT_LIBRARY_VISIBILITY FixedOpaqueExistentialContainer {
OpaqueExistentialContainer Header;
const void *WitnessTables[NumWitnessTables];
};
// We need to be able to instantiate for NumWitnessTables==0, which
// requires an explicit specialization.
template <>
struct FixedOpaqueExistentialContainer<0> {
OpaqueExistentialContainer Header;
};
/// A box implementation class for an opaque existential type with
/// a fixed number of witness tables.
template <unsigned NumWitnessTables>
struct SWIFT_LIBRARY_VISIBILITY OpaqueExistentialBox
: OpaqueExistentialBoxBase {
struct Container : FixedOpaqueExistentialContainer<NumWitnessTables> {
const Metadata *getType() const {
return this->Header.Type;
}
ValueBuffer *getBuffer() {
return &this->Header.Buffer;
}
void copyTypeInto(Container *dest) const {
this->Header.copyTypeInto(&dest->Header, NumWitnessTables);
}
static size_t getContainerStride() {
return sizeof(Container);
}
};
using type = Container;
static constexpr size_t size = sizeof(Container);
static constexpr size_t alignment = alignof(Container);
static constexpr size_t stride = sizeof(Container);
static constexpr size_t isPOD = false;
static constexpr bool isBitwiseTakable = true;
static constexpr unsigned numExtraInhabitants =
swift_getHeapObjectExtraInhabitantCount();
static void storeExtraInhabitantTag(Container *dest, unsigned tag) {
swift_storeHeapObjectExtraInhabitant(
const_cast<HeapObject **>(
reinterpret_cast<const HeapObject **>(&dest->Header.Type)),
tag - 1);
}
static unsigned getExtraInhabitantTag(const Container *src) {
return swift_getHeapObjectExtraInhabitantIndex(const_cast<HeapObject **>(
reinterpret_cast<const HeapObject *const *>(&src->Header.Type))) + 1;
}
};
/// A non-fixed box implementation class for an opaque existential
/// type with a dynamic number of witness tables.
struct SWIFT_LIBRARY_VISIBILITY NonFixedOpaqueExistentialBox
: OpaqueExistentialBoxBase {
struct Container {
OpaqueExistentialContainer Header;
const Metadata *getType() {
return Header.Type;
}
ValueBuffer *getBuffer(const Metadata *self) {
return &Header.Buffer;
}
void copyTypeInto(Container *dest, const Metadata *self) {
Header.copyTypeInto(&dest->Header, getNumWitnessTables(self));
}
static unsigned getNumWitnessTables(const Metadata *self) {
auto castSelf = static_cast<const ExistentialTypeMetadata*>(self);
return castSelf->Flags.getNumWitnessTables();
}
static size_t getAlignment(unsigned numWitnessTables) {
return std::max(alignof(void*), alignof(ValueBuffer));
}
static size_t getSize(unsigned numWitnessTables) {
constexpr size_t base = sizeof(OpaqueExistentialContainer);
static_assert(base > 0, "stride needs base size > 0");
return base + numWitnessTables * sizeof(void*);
}
static size_t getStride(unsigned numWitnessTables) {
return getSize(numWitnessTables);
}
static size_t getContainerStride(const Metadata *self) {
return getStride(getNumWitnessTables(self));
}
};
using type = Container;
static constexpr unsigned numExtraInhabitants =
swift_getHeapObjectExtraInhabitantCount();
static void storeExtraInhabitantTag(Container *dest, unsigned tag) {
swift_storeHeapObjectExtraInhabitant(
(HeapObject**)(uintptr_t)&dest->Header.Type, tag - 1);
}
static unsigned getExtraInhabitantTag(const Container *src) {
return swift_getHeapObjectExtraInhabitantIndex(
(HeapObject* const *)(uintptr_t)&src->Header.Type) + 1;
}
};
/// A common base class for fixed and non-fixed class-existential box
/// implementations.
struct SWIFT_LIBRARY_VISIBILITY ClassExistentialBoxBase
: ExistentialBoxBase<ClassExistentialBoxBase> {
static constexpr unsigned numExtraInhabitants =
swift_getHeapObjectExtraInhabitantCount();
template <class Container, class... A>
static void destroy(Container *value, A... args) {
swift_unknownObjectRelease(*value->getValueSlot());
}
template <class Container, class... A>
static Container *initializeWithCopy(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
auto newValue = *src->getValueSlot();
*dest->getValueSlot() = newValue;
swift_unknownObjectRetain(newValue);
return dest;
}
template <class Container, class... A>
static Container *initializeWithTake(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
*dest->getValueSlot() = *src->getValueSlot();
return dest;
}
template <class Container, class... A>
static Container *assignWithCopy(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
auto newValue = *src->getValueSlot();
auto oldValue = *dest->getValueSlot();
*dest->getValueSlot() = newValue;
swift_unknownObjectRetain(newValue);
swift_unknownObjectRelease(oldValue);
return dest;
}
template <class Container, class... A>
static Container *assignWithTake(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
auto newValue = *src->getValueSlot();
auto oldValue = *dest->getValueSlot();
*dest->getValueSlot() = newValue;
swift_unknownObjectRelease(oldValue);
return dest;
}
template <class Container, class... A>
static void storeExtraInhabitantTag(Container *dest, unsigned tag, A... args) {
swift_storeHeapObjectExtraInhabitant((HeapObject**) dest->getValueSlot(),
tag - 1);
}
template <class Container, class... A>
static int getExtraInhabitantTag(const Container *src, A... args) {
return swift_getHeapObjectExtraInhabitantIndex(
(HeapObject* const *) src->getValueSlot()) + 1;
}
};
/// A box implementation class for an existential container with
/// a class constraint and a fixed number of protocol witness tables.
template <unsigned NumWitnessTables>
struct SWIFT_LIBRARY_VISIBILITY ClassExistentialBox : ClassExistentialBoxBase {
struct Container {
ClassExistentialContainer Header;
const void *TypeInfo[NumWitnessTables];
void copyTypeInto(Container *dest) const {
for (unsigned i = 0; i != NumWitnessTables; ++i)
dest->TypeInfo[i] = TypeInfo[i];
}
void **getValueSlot() { return &Header.Value; }
void * const *getValueSlot() const { return &Header.Value; }
static size_t getContainerStride() { return sizeof(Container); }
};
using type = Container;
static constexpr size_t size = sizeof(Container);
static constexpr size_t alignment = alignof(Container);
static constexpr size_t stride = sizeof(Container);
static constexpr size_t isPOD = false;
static constexpr size_t isBitwiseTakable = true;
};
/// A non-fixed box implementation class for a class existential
/// type with a dynamic number of witness tables.
struct SWIFT_LIBRARY_VISIBILITY NonFixedClassExistentialBox
: ClassExistentialBoxBase {
struct Container {
ClassExistentialContainer Header;
static unsigned getNumWitnessTables(const Metadata *self) {
auto castSelf = static_cast<const ExistentialTypeMetadata*>(self);
return castSelf->Flags.getNumWitnessTables();
}
void copyTypeInto(Container *dest, const Metadata *self) {
Header.copyTypeInto(&dest->Header, getNumWitnessTables(self));
}
void **getValueSlot() { return &Header.Value; }
void * const *getValueSlot() const { return &Header.Value; }
static size_t getAlignment(unsigned numWitnessTables) {
return alignof(void*);
}
static size_t getSize(unsigned numWitnessTables) {
constexpr size_t base = sizeof(ClassExistentialContainer);
static_assert(base > 0, "stride needs base size > 0");
return base + numWitnessTables * sizeof(void*);
}
static size_t getStride(unsigned numWitnessTables) {
return getSize(numWitnessTables);
}
static size_t getContainerStride(const Metadata *self) {
return getStride(getNumWitnessTables(self));
}
};
using type = Container;
};
/// A common base class for fixed and non-fixed existential metatype box
/// implementations.
struct SWIFT_LIBRARY_VISIBILITY ExistentialMetatypeBoxBase
: ExistentialBoxBase<ExistentialMetatypeBoxBase> {
static constexpr unsigned numExtraInhabitants =
swift_getHeapObjectExtraInhabitantCount();
template <class Container, class... A>
static void destroy(Container *value, A... args) {
}
template <class Container, class... A>
static Container *initializeWithCopy(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
*dest->getValueSlot() = *src->getValueSlot();
return dest;
}
template <class Container, class... A>
static Container *initializeWithTake(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
*dest->getValueSlot() = *src->getValueSlot();
return dest;
}
template <class Container, class... A>
static Container *assignWithCopy(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
*dest->getValueSlot() = *src->getValueSlot();
return dest;
}
template <class Container, class... A>
static Container *assignWithTake(Container *dest, Container *src,
A... args) {
src->copyTypeInto(dest, args...);
*dest->getValueSlot() = *src->getValueSlot();
return dest;
}
template <class Container, class... A>
static void storeExtraInhabitantTag(Container *dest, unsigned tag, A... args) {
Metadata **MD = const_cast<Metadata **>(dest->getValueSlot());
swift_storeHeapObjectExtraInhabitant(reinterpret_cast<HeapObject **>(MD),
tag - 1);
}
template <class Container, class... A>
static int getExtraInhabitantTag(const Container *src, A... args) {
Metadata **MD = const_cast<Metadata **>(src->getValueSlot());
return swift_getHeapObjectExtraInhabitantIndex(
reinterpret_cast<HeapObject *const *>(MD)) + 1;
}
};
/// A box implementation class for an existential metatype container
/// with a fixed number of protocol witness tables.
template <unsigned NumWitnessTables>
struct SWIFT_LIBRARY_VISIBILITY ExistentialMetatypeBox
: ExistentialMetatypeBoxBase {
struct Container {
ExistentialMetatypeContainer Header;
const void *TypeInfo[NumWitnessTables];
void copyTypeInto(Container *dest) const {
for (unsigned i = 0; i != NumWitnessTables; ++i)
dest->TypeInfo[i] = TypeInfo[i];
}
const Metadata **getValueSlot() { return &Header.Value; }
const Metadata * const *getValueSlot() const { return &Header.Value; }
static size_t getContainerStride() { return sizeof(Container); }
};
using type = Container;
static constexpr size_t size = sizeof(Container);
static constexpr size_t alignment = alignof(Container);
static constexpr size_t stride = sizeof(Container);
static constexpr size_t isPOD = true;
static constexpr size_t isBitwiseTakable = true;
};
/// A non-fixed box implementation class for an existential metatype
/// type with a dynamic number of witness tables.
struct SWIFT_LIBRARY_VISIBILITY NonFixedExistentialMetatypeBox
: ExistentialMetatypeBoxBase {
struct Container {
ExistentialMetatypeContainer Header;
static unsigned getNumWitnessTables(const Metadata *self) {
auto castSelf = static_cast<const ExistentialMetatypeMetadata*>(self);
return castSelf->Flags.getNumWitnessTables();
}
void copyTypeInto(Container *dest, const Metadata *self) {
Header.copyTypeInto(&dest->Header, getNumWitnessTables(self));
}
const Metadata **getValueSlot() { return &Header.Value; }
const Metadata * const *getValueSlot() const { return &Header.Value; }
static size_t getAlignment(unsigned numWitnessTables) {
return alignof(void*);
}
static size_t getSize(unsigned numWitnessTables) {
constexpr size_t base = sizeof(ExistentialMetatypeContainer);
static_assert(base > 0, "stride needs base size > 0");
return base + numWitnessTables * sizeof(void*);
}
static size_t getStride(unsigned numWitnessTables) {
return getSize(numWitnessTables);
}
static size_t getContainerStride(const Metadata *self) {
return getStride(getNumWitnessTables(self));
}
};
using type = Container;
};
} // end namespace metadataimpl
} // end namespace swift
#endif /* SWIFT_RUNTIME_EXISTENTIALMETADATAIMPL_H */
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