[wasm] Add guard regions to end of WebAssembly.Memory buffers

src/wasm/wasm-module.h

 // Copyright 2015 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.
 
 #ifndef V8_WASM_MODULE_H_
 #define V8_WASM_MODULE_H_
 
 #include <memory>
 
 #include "src/api.h"
@@ skipping 18 matching lines @@
 
 const size_t kMaxModuleSize = 1024 * 1024 * 1024;
 const size_t kMaxFunctionSize = 128 * 1024;
 const size_t kMaxStringSize = 256;
 const uint32_t kWasmMagic = 0x6d736100;
 const uint32_t kWasmVersion = 0x0c;
 
 const uint8_t kWasmFunctionTypeForm = 0x40;
 const uint8_t kWasmAnyFunctionTypeForm = 0x20;
 
+#if V8_HOST_ARCH_64_BIT
+const size_t kWasmMaxHeapOffset = static_cast<size_t>(8) << 30;  // 8GB
+#endif
+
 enum WasmSectionCode {
   kUnknownSectionCode = 0,   // code for unknown sections
   kTypeSectionCode = 1,      // Function signature declarations
   kImportSectionCode = 2,    // Import declarations
   kFunctionSectionCode = 3,  // Function declarations
   kTableSectionCode = 4,     // Indirect function table and other tables
   kMemorySectionCode = 5,    // Memory attributes
   kGlobalSectionCode = 6,    // Global declarations
   kExportSectionCode = 7,    // Exports
   kStartSectionCode = 8,     // Start function declaration
@@ skipping 501 matching lines @@
 Object* GetOwningWasmInstance(Code* code);
 
 MaybeHandle<JSArrayBuffer> GetInstanceMemory(Isolate* isolate,
                                              Handle<JSObject> instance);
 
 int32_t GetInstanceMemorySize(Isolate* isolate, Handle<JSObject> instance);
 
 int32_t GrowInstanceMemory(Isolate* isolate, Handle<JSObject> instance,
                            uint32_t pages);
 
+Handle<JSArrayBuffer> NewArrayBuffer(Isolate* isolate, size_t size, bool guard);
+
 namespace testing {
 
 void ValidateInstancesChain(Isolate* isolate, Handle<JSObject> wasm_module,
                             int instance_count);
 void ValidateModuleState(Isolate* isolate, Handle<JSObject> wasm_module);
 void ValidateOrphanedInstance(Isolate* isolate, Handle<JSObject> instance);
 
 }  // namespace testing
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_MODULE_H_