WasmTable.h (5338B)
1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- 2 * vim: set ts=8 sts=2 et sw=2 tw=80: 3 * 4 * Copyright 2016 Mozilla Foundation 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 #ifndef wasm_table_h 20 #define wasm_table_h 21 22 #include "gc/Policy.h" 23 #include "wasm/WasmCode.h" 24 25 namespace js { 26 namespace wasm { 27 28 // A Table is an indexable array of opaque values. Tables are first-class 29 // stateful objects exposed to WebAssembly. asm.js also uses Tables to represent 30 // its homogeneous function-pointer tables. 31 // 32 // A table of FuncRef holds FunctionTableElems, which are (code*,instance*) 33 // pairs, where the instance must be traced. 34 // 35 // A table of AnyRef holds pointers, which must be traced. 36 37 using TableAnyRefVector = GCVector<HeapPtr<AnyRef>, 0, SystemAllocPolicy>; 38 39 class Table : public ShareableBase<Table> { 40 using InstanceSet = JS::WeakCache<GCHashSet< 41 WeakHeapPtr<WasmInstanceObject*>, 42 StableCellHasher<WeakHeapPtr<WasmInstanceObject*>>, SystemAllocPolicy>>; 43 using FuncRefVector = Vector<FunctionTableElem, 0, SystemAllocPolicy>; 44 45 WeakHeapPtr<WasmTableObject*> maybeObject_; 46 InstanceSet observers_; 47 FuncRefVector functions_; // either functions_ has data 48 TableAnyRefVector objects_; // or objects_, but not both 49 const AddressType addressType_; 50 const RefType elemType_; 51 const bool isAsmJS_; 52 uint32_t length_; 53 const mozilla::Maybe<uint64_t> maximum_; 54 55 template <class> 56 friend struct js::MallocProvider; 57 Table(JSContext* cx, const TableDesc& desc, 58 Handle<WasmTableObject*> maybeObject, FuncRefVector&& functions); 59 Table(JSContext* cx, const TableDesc& desc, 60 Handle<WasmTableObject*> maybeObject, TableAnyRefVector&& objects); 61 62 void tracePrivate(JSTracer* trc); 63 friend class js::WasmTableObject; 64 65 public: 66 static RefPtr<Table> create(JSContext* cx, const TableDesc& desc, 67 Handle<WasmTableObject*> maybeObject); 68 ~Table(); 69 void trace(JSTracer* trc); 70 71 AddressType addressType() const { return addressType_; } 72 RefType elemType() const { return elemType_; } 73 TableRepr repr() const { return elemType_.tableRepr(); } 74 75 bool isAsmJS() const { 76 MOZ_ASSERT(elemType_.isFuncHierarchy()); 77 return isAsmJS_; 78 } 79 80 bool isFunction() const { return elemType().isFuncHierarchy(); } 81 uint32_t length() const { return length_; } 82 mozilla::Maybe<uint64_t> maximum() const { return maximum_; } 83 84 // Raw pointer to the table for use in TableInstanceData. 85 uint8_t* instanceElements() const; 86 87 // set/get/fillFuncRef is allowed only on table-of-funcref. 88 // get/fillAnyRef is allowed only on table-of-anyref. 89 // setNull is allowed on either. 90 91 const FunctionTableElem& getFuncRef(uint32_t address) const; 92 [[nodiscard]] bool getFuncRef(JSContext* cx, uint32_t address, 93 MutableHandleFunction fun) const; 94 void setFuncRef(uint32_t address, JSFunction* func); 95 void setFuncRef(uint32_t address, void* code, Instance* instance); 96 void fillFuncRef(uint32_t address, uint32_t fillCount, FuncRef ref, 97 JSContext* cx); 98 99 AnyRef getAnyRef(uint32_t address) const; 100 void setAnyRef(uint32_t address, AnyRef ref); 101 void fillAnyRef(uint32_t address, uint32_t fillCount, AnyRef ref); 102 103 // Sets ref automatically using the correct setter depending on the ref and 104 // table type (setNull, setFuncRef, or setAnyRef) 105 void setRef(uint32_t address, AnyRef ref); 106 107 // Get the element at address and convert it to a JS value. 108 [[nodiscard]] bool getValue(JSContext* cx, uint32_t address, 109 MutableHandleValue result) const; 110 111 void setNull(uint32_t address); 112 113 // Copy entry from |srcTable| at |srcIndex| to this table at |dstIndex|. Used 114 // by table.copy. May OOM if it needs to box up a function during an upcast. 115 [[nodiscard]] bool copy(JSContext* cx, const Table& srcTable, 116 uint32_t dstIndex, uint32_t srcIndex); 117 118 // grow() returns (uint32_t)-1 if it could not grow. 119 [[nodiscard]] uint32_t grow(uint32_t delta); 120 [[nodiscard]] bool movingGrowable() const; 121 [[nodiscard]] bool addMovingGrowObserver(JSContext* cx, 122 WasmInstanceObject* instance); 123 124 void fillUninitialized(uint32_t address, uint32_t fillCount, HandleAnyRef ref, 125 JSContext* cx); 126 #ifdef DEBUG 127 void assertRangeNull(uint32_t address, uint32_t length) const; 128 void assertRangeNotNull(uint32_t address, uint32_t length) const; 129 #endif // DEBUG 130 131 // about:memory reporting: 132 133 size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const; 134 135 size_t gcMallocBytes() const; 136 }; 137 138 using SharedTable = RefPtr<Table>; 139 using SharedTableVector = Vector<SharedTable, 0, SystemAllocPolicy>; 140 141 } // namespace wasm 142 } // namespace js 143 144 #endif // wasm_table_h