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//===------------- Array.cpp - Swift Array Operations Support -------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Implementations of the array runtime functions.
//
// arrayInitWithCopy(T *dest, T *src, size_t count, M* self)
// arrayInitWithTake(NoAlias|FrontToBack|BackToFront)(T *dest, T *src,
// size_t count, M* self)
// arrayAssignWithCopy(NoAlias|FrontToBack|BackToFront)(T *dest, T *src,
// size_t count, M* self)
// arrayAssignWithTake(T *dest, T *src, size_t count, M* self)
// arrayDestroy(T *dst, size_t count, M* self)
//
//===----------------------------------------------------------------------===//
#include "BytecodeLayouts.h"
#include "swift/Runtime/Config.h"
#include "swift/Runtime/HeapObject.h"
#include "swift/Runtime/Metadata.h"
using namespace swift;
namespace {
enum class ArrayCopy : unsigned {
NoAlias = 0,
FrontToBack = 1,
BackToFront = 2
};
enum class ArraySource {
Copy,
Take
};
enum class ArrayDest {
Init,
Assign
};
} // end anonymous namespace.
static void array_pod_copy(ArrayCopy copyKind, OpaqueValue *dest,
OpaqueValue *src, size_t stride, size_t count) {
if (copyKind == ArrayCopy::NoAlias) {
memcpy(dest, src, stride * count);
return;
}
assert(copyKind == ArrayCopy::FrontToBack ||
copyKind == ArrayCopy::BackToFront);
memmove(dest, src, stride * count);
}
namespace {
typedef OpaqueValue *(*const WitnessFunction)(OpaqueValue *, OpaqueValue *,
const Metadata *);
}
template <ArrayDest destOp, ArraySource srcOp>
static WitnessFunction get_witness_function(const ValueWitnessTable *wtable) {
if (destOp == ArrayDest::Init) {
if (srcOp == ArraySource::Copy)
return wtable->initializeWithCopy;
else {
assert(srcOp == ArraySource::Take);
return wtable->initializeWithTake;
}
} else {
assert(destOp == ArrayDest::Assign);
if (srcOp == ArraySource::Copy) {
return wtable->assignWithCopy;
} else {
assert(srcOp == ArraySource::Take);
return wtable->assignWithTake;
}
}
}
template <ArrayDest destOp, ArraySource srcOp, ArrayCopy copyKind>
static void array_copy_operation(OpaqueValue *dest, OpaqueValue *src,
size_t count, const Metadata *self) {
if (count == 0)
return;
auto wtable = self->getValueWitnesses();
auto stride = wtable->getStride();
// If we are doing a copy we need PODness for a memcpy.
if (srcOp == ArraySource::Copy) {
auto isPOD = wtable->isPOD();
if (isPOD) {
array_pod_copy(copyKind, dest, src, stride, count);
return;
}
} else {
// Otherwise, we are doing a take and need bitwise takability for a copy.
assert(srcOp == ArraySource::Take);
auto isBitwiseTakable = wtable->isBitwiseTakable();
if (isBitwiseTakable && (destOp == ArrayDest::Init || wtable->isPOD())) {
array_pod_copy(copyKind, dest, src, stride, count);
return;
}
}
// Call the witness to do the copy.
if (copyKind == ArrayCopy::NoAlias || copyKind == ArrayCopy::FrontToBack) {
if (self->hasLayoutString() && destOp == ArrayDest::Init &&
srcOp == ArraySource::Copy) {
return swift_generic_arrayInitWithCopy(dest, src, count, stride, self);
}
if (self->hasLayoutString() && destOp == ArrayDest::Assign &&
srcOp == ArraySource::Copy) {
return swift_generic_arrayAssignWithCopy(dest, src, count, stride, self);
}
auto copy = get_witness_function<destOp, srcOp>(wtable);
for (size_t i = 0; i < count; ++i) {
auto offset = i * stride;
auto *from = reinterpret_cast<OpaqueValue *>((char *)src + offset);
auto *to = reinterpret_cast<OpaqueValue *>((char *)dest + offset);
copy(to, from, self);
}
return;
}
// Back-to-front copy.
assert(copyKind == ArrayCopy::BackToFront);
assert(count != 0);
auto copy = get_witness_function<destOp, srcOp>(wtable);
size_t i = count;
do {
auto offset = --i * stride;
auto *from = reinterpret_cast<OpaqueValue *>((char *)src + offset);
auto *to = reinterpret_cast<OpaqueValue *>((char *)dest + offset);
copy(to, from, self);
} while (i != 0);
}
SWIFT_RUNTIME_EXPORT
void swift_arrayInitWithCopy(OpaqueValue *dest, OpaqueValue *src, size_t count,
const Metadata *self) {
array_copy_operation<ArrayDest::Init, ArraySource::Copy, ArrayCopy::NoAlias>(
dest, src, count, self);
}
SWIFT_RUNTIME_EXPORT
void swift_arrayInitWithTakeNoAlias(OpaqueValue *dest, OpaqueValue *src,
size_t count, const Metadata *self) {
array_copy_operation<ArrayDest::Init, ArraySource::Take, ArrayCopy::NoAlias>(
dest, src, count, self);
}
SWIFT_RUNTIME_EXPORT
void swift_arrayInitWithTakeFrontToBack(OpaqueValue *dest, OpaqueValue *src,
size_t count, const Metadata *self) {
array_copy_operation<ArrayDest::Init, ArraySource::Take,
ArrayCopy::FrontToBack>(dest, src, count, self);
}
SWIFT_RUNTIME_EXPORT
void swift_arrayInitWithTakeBackToFront(OpaqueValue *dest, OpaqueValue *src,
size_t count, const Metadata *self) {
array_copy_operation<ArrayDest::Init, ArraySource::Take,
ArrayCopy::BackToFront>(dest, src, count, self);
}
SWIFT_RUNTIME_EXPORT
void swift_arrayAssignWithCopyNoAlias(OpaqueValue *dest, OpaqueValue *src,
size_t count, const Metadata *self) {
array_copy_operation<ArrayDest::Assign, ArraySource::Copy,
ArrayCopy::NoAlias>(dest, src, count, self);
}
SWIFT_RUNTIME_EXPORT
void swift_arrayAssignWithCopyFrontToBack(OpaqueValue *dest, OpaqueValue *src,
size_t count, const Metadata *self) {
array_copy_operation<ArrayDest::Assign, ArraySource::Copy,
ArrayCopy::FrontToBack>(dest, src, count, self);
}
SWIFT_RUNTIME_EXPORT
void swift_arrayAssignWithCopyBackToFront(OpaqueValue *dest, OpaqueValue *src,
size_t count, const Metadata *self) {
array_copy_operation<ArrayDest::Assign, ArraySource::Copy,
ArrayCopy::BackToFront>(dest, src, count, self);
}
SWIFT_RUNTIME_EXPORT
void swift_arrayAssignWithTake(OpaqueValue *dest, OpaqueValue *src,
size_t count, const Metadata *self) {
array_copy_operation<ArrayDest::Assign, ArraySource::Take,
ArrayCopy::NoAlias>(dest, src, count, self);
}
SWIFT_RUNTIME_EXPORT
void swift_arrayDestroy(OpaqueValue *begin, size_t count, const Metadata *self) {
if (count == 0)
return;
auto wtable = self->getValueWitnesses();
// Nothing to do if the type is POD.
if (wtable->isPOD())
return;
auto stride = wtable->getStride();
if (self->hasLayoutString()) {
return swift_generic_arrayDestroy(begin, count, stride, self);
}
for (size_t i = 0; i < count; ++i) {
auto offset = i * stride;
auto *obj = reinterpret_cast<OpaqueValue *>((char *)begin + offset);
wtable->destroy(obj, self);
}
}
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