decisions

This commit is contained in:
dcode
2019-03-15 09:26:31 +01:00
parent 139cec0846
commit 968b0321a0
20 changed files with 619 additions and 557 deletions

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@ -1,135 +1,166 @@
import { AL_MASK, MAX_SIZE_32 } from "./util/allocator";
import { HEAP_BASE, memory } from "./memory";
import { gc } from "./gc";
/** Common runtime. */
export namespace runtime {
/** Whether the memory manager interface is implemented. */
// @ts-ignore: decorator, stub
@lazy export const MM_IMPLEMENTED: bool = isDefined(__memory_allocate);
/** Common runtime header of all objects. */
@unmanaged export class Header {
/** Whether the garbage collector interface is implemented. */
// @ts-ignore: decorator, stub
@lazy export const GC_IMPLEMENTED: bool = isDefined(__gc_register);
/** Size of a runtime header. */
// @ts-ignore: decorator
@lazy @inline
static readonly SIZE: usize = gc.implemented
? (offsetof<runtime.Header>( ) + AL_MASK) & ~AL_MASK // full header if GC is present
: (offsetof<runtime.Header>("gc1") + AL_MASK) & ~AL_MASK; // half header if GC is absent
/** Common runtime header. Each managed object has one. */
@unmanaged export class HEADER {
/** Unique id of the respective class or a magic value if not yet registered.*/
classId: u32;
/** Size of the allocated payload. */
payloadSize: u32;
/** Reserved field for use by GC. Only present if GC is. */
gc1: usize; // itcm: tagged next
/** Reserved field for use by GC. Only present if GC is. */
gc2: usize; // itcm: prev
}
/** Magic value used to validate runtime headers. */
// @ts-ignore: decorator
@lazy @inline
static readonly MAGIC: u32 = 0xA55E4B17;
/** Common runtime header size. */
export const HEADER_SIZE: usize = GC_IMPLEMENTED
? (offsetof<HEADER>( ) + AL_MASK) & ~AL_MASK // full header if GC is present
: (offsetof<HEADER>("gc1") + AL_MASK) & ~AL_MASK; // half header if GC is absent
/** Unique id of the respective class or a magic value if not yet registered.*/
classId: u32;
/** Size of the allocated payload. */
payloadSize: u32;
/** Reserved field for use by GC. Only present if GC is. */
gc1: usize; // itcm: tagged next
/** Reserved field for use by GC. Only present if GC is. */
gc2: usize; // itcm: prev
/** Common runtime header magic. Used to assert registered/unregistered status. */
export const HEADER_MAGIC: u32 = 0xA55E4B17;
/** Gets the computed unique class id of a class type. */
// @ts-ignore: decorator
@unsafe @builtin
export declare function CLASSID<T>(): u32;
/** Iterates over all root objects of a reference type. */
// @ts-ignore: decorator
@unsafe @builtin
export declare function ITERATEROOTS(fn: (ref: usize) => void): void;
/** Adjusts an allocation to actual block size. Primarily targets TLSF. */
export function ADJUST(payloadSize: usize): usize {
// round up to power of 2, e.g. with HEADER_SIZE=8:
// 0 -> 2^3 = 8
// 1..8 -> 2^4 = 16
// 9..24 -> 2^5 = 32
// ...
// MAX_LENGTH -> 2^30 = 0x40000000 (MAX_SIZE_32)
return <usize>1 << <usize>(<u32>32 - clz<u32>(payloadSize + HEADER_SIZE - 1));
}
/** Allocates a new object and returns a pointer to its payload. Does not fill. */
// @ts-ignore: decorator
@unsafe
export function ALLOCATE(payloadSize: usize): usize {
var header = changetype<HEADER>(memory.allocate(ADJUST(payloadSize)));
header.classId = HEADER_MAGIC;
header.payloadSize = payloadSize;
if (GC_IMPLEMENTED) {
header.gc1 = 0;
header.gc2 = 0;
}
return changetype<usize>(header) + HEADER_SIZE;
}
// Note that header data and layout isn't quite optimal depending on which allocator one
// decides to use, but it's done this way for maximum flexibility. Also remember that the
// runtime will most likely change significantly once reftypes and WASM GC are a thing.
/** Adjusts an allocation to actual block size. Primarily targets TLSF. */
function adjust(payloadSize: usize): usize {
// round up to power of 2, e.g. with HEADER_SIZE=8:
// 0 -> 2^3 = 8
// 1..8 -> 2^4 = 16
// 9..24 -> 2^5 = 32
// ...
// MAX_LENGTH -> 2^30 = 0x40000000 (MAX_SIZE_32)
return <usize>1 << <usize>(<u32>32 - clz<u32>(payloadSize + Header.SIZE - 1));
}
/** Allocates a new object and returns a pointer to its payload. Does not fill. */
// @ts-ignore: decorator
@unsafe
export function alloc(payloadSize: u32): usize {
var header = changetype<Header>(memory.allocate(adjust(payloadSize)));
header.classId = Header.MAGIC;
header.payloadSize = payloadSize;
if (gc.implemented) {
header.gc1 = 0;
header.gc2 = 0;
}
return changetype<usize>(header) + Header.SIZE;
}
/** Reallocates an object if necessary. Returns a pointer to its (moved) payload. */
// @ts-ignore: decorator
@unsafe
export function realloc(ref: usize, newPayloadSize: u32): usize {
// Background: When managed objects are allocated these aren't immediately registered with GC
// but can be used as scratch objects while unregistered. This is useful in situations where
// the object must be reallocated multiple times because its final size isn't known beforehand,
// e.g. in Array#filter, with only the final object making it into GC'ed userland.
var header = changetype<Header>(ref - Header.SIZE);
var payloadSize = header.payloadSize;
if (payloadSize < newPayloadSize) {
let newAdjustedSize = adjust(newPayloadSize);
if (select(adjust(payloadSize), 0, ref > HEAP_BASE) < newAdjustedSize) {
// move if the allocation isn't large enough or not a heap object
let newHeader = changetype<Header>(memory.allocate(newAdjustedSize));
newHeader.classId = header.classId;
if (gc.implemented) {
newHeader.gc1 = 0;
newHeader.gc2 = 0;
}
let newRef = changetype<usize>(newHeader) + Header.SIZE;
memory.copy(newRef, ref, payloadSize);
memory.fill(newRef + payloadSize, 0, newPayloadSize - payloadSize);
if (header.classId == Header.MAGIC) {
// free right away if not registered yet
assert(ref > HEAP_BASE); // static objects aren't scratch objects
memory.free(changetype<usize>(header));
} else if (gc.implemented) {
// if previously registered, register again
// @ts-ignore: stub
__gc_register(ref);
}
header = newHeader;
ref = newRef;
} else {
// otherwise just clear additional memory within this block
memory.fill(ref + payloadSize, 0, newPayloadSize - payloadSize);
/** Reallocates an object if necessary. Returns a pointer to its (moved) payload. */
// @ts-ignore: decorator
@unsafe
export function REALLOCATE(ref: usize, newPayloadSize: usize): usize {
// Background: When managed objects are allocated these aren't immediately registered with GC
// but can be used as scratch objects while unregistered. This is useful in situations where
// the object must be reallocated multiple times because its final size isn't known beforehand,
// e.g. in Array#filter, with only the final object making it into GC'ed userland.
var header = changetype<HEADER>(ref - HEADER_SIZE);
var payloadSize = header.payloadSize;
if (payloadSize < newPayloadSize) {
let newAdjustedSize = ADJUST(newPayloadSize);
if (select(ADJUST(payloadSize), 0, ref > HEAP_BASE) < newAdjustedSize) {
// move if the allocation isn't large enough or not a heap object
let newHeader = changetype<HEADER>(memory.allocate(newAdjustedSize));
newHeader.classId = header.classId;
if (GC_IMPLEMENTED) {
newHeader.gc1 = 0;
newHeader.gc2 = 0;
}
let newRef = changetype<usize>(newHeader) + HEADER_SIZE;
memory.copy(newRef, ref, payloadSize);
memory.fill(newRef + payloadSize, 0, newPayloadSize - payloadSize);
if (header.classId == HEADER_MAGIC) {
// free right away if not registered yet
assert(ref > HEAP_BASE); // static objects aren't scratch objects
memory.free(changetype<usize>(header));
} else if (GC_IMPLEMENTED) {
// if previously registered, register again
// @ts-ignore: stub
__gc_register(ref);
}
header = newHeader;
ref = newRef;
} else {
// if the size is the same or less, just update the header accordingly.
// unused space is cleared when grown, so no need to do this here.
// otherwise just clear additional memory within this block
memory.fill(ref + payloadSize, 0, newPayloadSize - payloadSize);
}
header.payloadSize = newPayloadSize;
return ref;
} else {
// if the size is the same or less, just update the header accordingly.
// unused space is cleared when grown, so no need to do this here.
}
header.payloadSize = newPayloadSize;
return ref;
}
// @ts-ignore: decorator
@unsafe
export function unrefUnregistered(ref: usize): Header {
assert(ref >= HEAP_BASE + Header.SIZE); // must be a heap object
var header = changetype<Header>(ref - Header.SIZE);
assert(header.classId == Header.MAGIC); // must be unregistered
return header;
}
/** Registers a managed object to be tracked by the garbage collector, if present. */
// @ts-ignore: decorator
@unsafe @inline
export function REGISTER<T>(ref: usize): T {
ASSERT_UNREGISTERED(ref);
changetype<HEADER>(ref - HEADER_SIZE).classId = CLASSID<T>();
// @ts-ignore: stub
if (GC_IMPLEMENTED) __gc_register(ref);
return changetype<T>(ref);
}
/** Frees an unregistered object that turned out to be unnecessary. */
// @ts-ignore: decorator
@unsafe @inline
export function freeUnregistered<T>(ref: T): void {
memory.free(changetype<usize>(unrefUnregistered(changetype<usize>(ref))));
}
/** Links a registered object with the (registered) object now referencing it. */
// @ts-ignore: decorator
@unsafe @inline
export function LINK<T,TParent>(ref: T, parentRef: TParent): void {
ASSERT_REGISTERED(changetype<usize>(ref));
ASSERT_REGISTERED(changetype<usize>(parentRef));
// @ts-ignore: stub
if (GC_IMPLEMENTED) __gc_link(changetype<usize>(ref), changetype<usize>(parentRef));
}
/** Discards an unregistered object that turned out to be unnecessary. */
// @ts-ignore: decorator
export function DISCARD(ref: usize): void {
ASSERT_UNREGISTERED(ref);
memory.free(changetype<usize>(ref - HEADER_SIZE));
}
// Helpers
/** Asserts that a managed object is still unregistered. */
function ASSERT_UNREGISTERED(ref: usize): void {
assert(ref > HEAP_BASE); // must be a heap object
assert(changetype<HEADER>(ref - HEADER_SIZE).classId == HEADER_MAGIC);
}
/** Asserts that a managed object has already been registered. */
function ASSERT_REGISTERED(ref: usize): void {
assert(ref > HEAP_BASE); // must be a heap object
assert(changetype<HEADER>(ref - HEADER_SIZE).classId != HEADER_MAGIC);
}
import { ArrayBuffer } from "./arraybuffer";
/** Maximum byte length of any buffer. */
// @ts-ignore: decorator
@lazy
export const MAX_BYTELENGTH: i32 = MAX_SIZE_32 - HEADER_SIZE;
/** Hard wired ArrayBufferView interface. */
export abstract class ArrayBufferView {
// @ts-ignore: decorator
@lazy
static readonly MAX_BYTELENGTH: i32 = MAX_SIZE_32 - runtime.Header.SIZE;
[key: number]: number;
// @ts-ignore: decorator
@ -145,7 +176,7 @@ export abstract class ArrayBufferView {
dataEnd: usize;
constructor(length: i32, alignLog2: i32) {
if (<u32>length > <u32>ArrayBufferView.MAX_BYTELENGTH >>> alignLog2) throw new RangeError("Invalid length");
if (<u32>length > <u32>MAX_BYTELENGTH >>> alignLog2) throw new RangeError("Invalid length");
var buffer = new ArrayBuffer(length << alignLog2);
this.data = buffer;
this.dataStart = changetype<usize>(buffer);
@ -161,7 +192,7 @@ export abstract class ArrayBufferView {
}
get length(): i32 {
ERROR("missing implementation: [T extends ArrayBufferView]#length");
ERROR("missing implementation: subclasses must implement ArrayBufferView#length");
return unreachable();
}
}