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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* Copyright 2016 Mozilla Foundation
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#ifndef wasm_table_h
#define wasm_table_h
#include "gc/Policy.h"
#include "wasm/WasmCode.h"
namespace js {
namespace wasm {
// A Table is an indexable array of opaque values. Tables are first-class
// stateful objects exposed to WebAssembly. asm.js also uses Tables to represent
// its homogeneous function-pointer tables.
// A table of FuncRef holds FunctionTableElems, which are (code*,tls*) pairs,
// where the tls must be traced.
// A table of AnyRef holds JSObject pointers, which must be traced.
// TODO/AnyRef-boxing: With boxed immediates and strings, JSObject* is no longer
// the most appropriate representation for Cell::anyref.
typedef GCVector<HeapPtr<JSObject*>, 0, SystemAllocPolicy> TableAnyRefVector;
class Table : public ShareableBase<Table> {
using InstanceSet =
using UniqueFuncRefArray = UniquePtr<FunctionTableElem[], JS::FreePolicy>;
WeakHeapPtrWasmTableObject maybeObject_;
InstanceSet observers_;
UniqueFuncRefArray functions_; // either functions_ has data
TableAnyRefVector objects_; // or objects_, but not both
const TableKind kind_;
uint32_t length_;
const Maybe<uint32_t> maximum_;
template <class>
friend struct js::MallocProvider;
Table(JSContext* cx, const TableDesc& td, HandleWasmTableObject maybeObject,
UniqueFuncRefArray functions);
Table(JSContext* cx, const TableDesc& td, HandleWasmTableObject maybeObject,
TableAnyRefVector&& objects);
void tracePrivate(JSTracer* trc);
friend class js::WasmTableObject;
static RefPtr<Table> create(JSContext* cx, const TableDesc& desc,
HandleWasmTableObject maybeObject);
void trace(JSTracer* trc);
TableKind kind() const { return kind_; }
TableRepr repr() const {
switch (kind()) {
case TableKind::AnyRef:
return TableRepr::Ref;
case TableKind::FuncRef:
case TableKind::AsmJS:
return TableRepr::Func;
bool isFunction() const {
return kind_ == TableKind::FuncRef || kind_ == TableKind::AsmJS;
uint32_t length() const { return length_; }
Maybe<uint32_t> maximum() const { return maximum_; }
// Only for function values. Raw pointer to the table.
uint8_t* functionBase() const;
// set/get/fillFuncRef is allowed only on table-of-funcref.
// get/fillAnyRef is allowed only on table-of-anyref.
// setNull is allowed on either.
const FunctionTableElem& getFuncRef(uint32_t index) const;
bool getFuncRef(JSContext* cx, uint32_t index,
MutableHandleFunction fun) const;
void setFuncRef(uint32_t index, void* code, const Instance* instance);
void fillFuncRef(uint32_t index, uint32_t fillCount, FuncRef ref,
JSContext* cx);
AnyRef getAnyRef(uint32_t index) const;
void fillAnyRef(uint32_t index, uint32_t fillCount, AnyRef ref);
void setNull(uint32_t index);
// Copy entry from |srcTable| at |srcIndex| to this table at |dstIndex|. Used
// by table.copy. May OOM if it needs to box up a function during an upcast.
bool copy(const Table& srcTable, uint32_t dstIndex, uint32_t srcIndex);
// grow() returns (uint32_t)-1 if it could not grow.
uint32_t grow(uint32_t delta);
bool movingGrowable() const;
bool addMovingGrowObserver(JSContext* cx, WasmInstanceObject* instance);
// about:memory reporting:
size_t sizeOfExcludingThis(MallocSizeOf mallocSizeOf) const;
size_t gcMallocBytes() const;
using SharedTable = RefPtr<Table>;
typedef Vector<SharedTable, 0, SystemAllocPolicy> SharedTableVector;
} // namespace wasm
} // namespace js
#endif // wasm_table_h