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

src/wasm/wasm-module.h

Index: src/wasm/wasm-module.h
diff --git a/src/wasm/wasm-module.h b/src/wasm/wasm-module.h
index 62f4285af4ddc2d60c5d32458ed8e44e86b6c7cc..9ae1cc2aa81b7fb7e81b80517ef1e99d4c2c06d5 100644
--- a/src/wasm/wasm-module.h
+++ b/src/wasm/wasm-module.h
@@ -36,6 +36,10 @@ 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
@@ -557,6 +561,8 @@ 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,