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// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
namespace torque_internal {
// Unsafe is a marker that we require to be passed when calling internal APIs
// that might lead to unsoundness when used incorrectly. Unsafe markers should
// therefore not be instantiated anywhere outside of this namespace.
struct Unsafe {}
// Size of a type in memory (on the heap). For class types, this is the size
// of the pointer, not of the instance.
intrinsic %SizeOf<T: type>(): constexpr int31;
struct Reference<T: type> {
const object: HeapObject;
const offset: intptr;
unsafeMarker: Unsafe;
}
type ConstReference<T: type> extends Reference<T>;
type MutableReference<T: type> extends ConstReference<T>;
namespace unsafe {
macro NewReference<T: type>(object: HeapObject, offset: intptr):&T {
return %RawDownCast<&T>(
Reference<T>{object: object, offset: offset, unsafeMarker: Unsafe {}});
}
} // namespace unsafe
struct Slice<T: type> {
macro TryAtIndex(index: intptr):&T labels OutOfBounds {
if (Convert<uintptr>(index) < Convert<uintptr>(this.length)) {
return unsafe::NewReference<T>(
this.object, this.offset + index * %SizeOf<T>());
} else {
goto OutOfBounds;
}
}
macro AtIndex(index: intptr):&T {
return this.TryAtIndex(index) otherwise unreachable;
}
macro AtIndex(index: uintptr):&T {
return this.TryAtIndex(Convert<intptr>(index)) otherwise unreachable;
}
macro AtIndex(index: constexpr int31):&T {
const i: intptr = Convert<intptr>(index);
return this.TryAtIndex(i) otherwise unreachable;
}
macro AtIndex(index: Smi):&T {
const i: intptr = Convert<intptr>(index);
return this.TryAtIndex(i) otherwise unreachable;
}
macro Iterator(): SliceIterator<T> {
const end = this.offset + this.length * %SizeOf<T>();
return SliceIterator<T>{
object: this.object,
start: this.offset,
end: end,
unsafeMarker: Unsafe {}
};
}
macro Iterator(startIndex: intptr, endIndex: intptr): SliceIterator<T> {
check(
Convert<uintptr>(endIndex) <= Convert<uintptr>(this.length) &&
Convert<uintptr>(startIndex) <= Convert<uintptr>(endIndex));
const start = this.offset + startIndex * %SizeOf<T>();
const end = this.offset + endIndex * %SizeOf<T>();
return SliceIterator<T>{
object: this.object,
start,
end,
unsafeMarker: Unsafe {}
};
}
const object: HeapObject;
const offset: intptr;
const length: intptr;
unsafeMarker: Unsafe;
}
macro UnsafeNewSlice<T: type>(
object: HeapObject, offset: intptr, length: intptr): Slice<T> {
return Slice<T>{
object: object,
offset: offset,
length: length,
unsafeMarker: Unsafe {}
};
}
struct SliceIterator<T: type> {
macro Empty(): bool {
return this.start == this.end;
}
macro Next(): T labels NoMore {
return * this.NextReference() otherwise NoMore;
}
macro NextReference():&T labels NoMore {
if (this.Empty()) {
goto NoMore;
} else {
const result = unsafe::NewReference<T>(this.object, this.start);
this.start += %SizeOf<T>();
return result;
}
}
object: HeapObject;
start: intptr;
end: intptr;
unsafeMarker: Unsafe;
}
macro AddIndexedFieldSizeToObjectSize(
baseSize: intptr, arrayLength: intptr, fieldSize: constexpr int32): intptr {
const arrayLength = Convert<int32>(arrayLength);
const byteLength = TryInt32Mul(arrayLength, fieldSize)
otherwise unreachable;
return TryIntPtrAdd(baseSize, Convert<intptr>(byteLength))
otherwise unreachable;
}
macro AlignTagged(x: intptr): intptr {
// Round up to a multiple of kTaggedSize.
return (x + kObjectAlignmentMask) & ~kObjectAlignmentMask;
}
macro IsTaggedAligned(x: intptr): bool {
return (x & kObjectAlignmentMask) == 0;
}
macro ValidAllocationSize(sizeInBytes: intptr, map: Map): bool {
if (sizeInBytes <= 0) return false;
if (!IsTaggedAligned(sizeInBytes)) return false;
const instanceSizeInWords = Convert<intptr>(map.instance_size_in_words);
return instanceSizeInWords == kVariableSizeSentinel ||
instanceSizeInWords * kTaggedSize == sizeInBytes;
}
type UninitializedHeapObject extends HeapObject;
extern macro AllocateAllowLOS(intptr): UninitializedHeapObject;
extern macro GetInstanceTypeMap(constexpr InstanceType): Map;
macro Allocate(sizeInBytes: intptr, map: Map): UninitializedHeapObject {
assert(ValidAllocationSize(sizeInBytes, map));
return AllocateAllowLOS(sizeInBytes);
}
macro InitializeFieldsFromIterator<T: type, Iterator: type>(
target: Slice<T>, originIterator: Iterator) {
let targetIterator = target.Iterator();
let originIterator = originIterator;
while (true) {
const ref:&T = targetIterator.NextReference() otherwise break;
* ref = originIterator.Next() otherwise unreachable;
}
}
// Dummy implementations: do not initialize for UninitializedIterator.
InitializeFieldsFromIterator<char8, UninitializedIterator>(
_target: Slice<char8>, _originIterator: UninitializedIterator) {}
InitializeFieldsFromIterator<char16, UninitializedIterator>(
_target: Slice<char16>, _originIterator: UninitializedIterator) {}
extern macro IsDoubleHole(HeapObject, intptr): bool;
extern macro StoreDoubleHole(HeapObject, intptr);
macro LoadFloat64OrHole(r:&float64_or_hole): float64_or_hole {
return float64_or_hole{
is_hole: IsDoubleHole(r.object, r.offset - kHeapObjectTag),
value: * unsafe::NewReference<float64>(r.object, r.offset)
};
}
macro StoreFloat64OrHole(r:&float64_or_hole, value: float64_or_hole) {
if (value.is_hole) {
StoreDoubleHole(r.object, r.offset - kHeapObjectTag);
} else {
* unsafe::NewReference<float64>(r.object, r.offset) = value.value;
}
}
} // namespace torque_internal
// Indicates that an array-field should not be initialized.
// For safety reasons, this is only allowed for untagged types.
struct UninitializedIterator {}
// %RawDownCast should *never* be used anywhere in Torque code except for
// in Torque-based UnsafeCast operators preceeded by an appropriate
// type assert()
intrinsic %RawDownCast<To: type, From: type>(x: From): To;
intrinsic %RawConstexprCast<To: type, From: type>(f: From): To;
struct IteratorSequence<T: type, FirstIterator: type, SecondIterator: type> {
macro Empty(): bool {
return this.first.Empty() && this.second.Empty();
}
macro Next(): T labels NoMore {
return this.first.Next()
otherwise return (this.second.Next() otherwise NoMore);
}
first: FirstIterator;
second: SecondIterator;
}
macro IteratorSequence<T: type, FirstIterator: type, SecondIterator: type>(
first: FirstIterator, second: SecondIterator):
IteratorSequence<T, FirstIterator, SecondIterator> {
return IteratorSequence<T>{first, second};
}
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