[wasm] Adding feature to JIT a wasm function at runtime and hook up the compiled code into the indi…

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 "src/api.h"
 #include "src/handles.h"
 #include "src/wasm/wasm-opcodes.h"
@@ skipping 172 matching lines @@
   std::vector<WasmExport> export_table;        // export table.
   // We store the semaphore here to extend its lifetime. In <libc-2.21, which we
   // use on the try bots, semaphore::Wait() can return while some compilation
   // tasks are still executing semaphore::Signal(). If the semaphore is cleaned
   // up right after semaphore::Wait() returns, then this can cause an
   // invalid-semaphore error in the compilation tasks.
   // TODO(wasm): Move this semaphore back to CompileInParallel when the try bots
   // switch to libc-2.21 or higher.
   base::SmartPointer<base::Semaphore> pending_tasks;
 
-  WasmModule();
+  WasmModule() : WasmModule(nullptr) {}
+  explicit WasmModule(byte* module_start);
 
   // Get a string stored in the module bytes representing a name.
   WasmName GetName(uint32_t offset, uint32_t length) const {
     if (length == 0) return {"<?>", 3};  // no name.
     CHECK(BoundsCheck(offset, offset + length));
     DCHECK_GE(static_cast<int>(length), 0);
     return {reinterpret_cast<const char*>(module_start + offset),
             static_cast<int>(length)};
   }
 
@@ skipping 182 matching lines @@
 // given encoded module. The module should have no imports.
 int32_t CompileAndRunWasmModule(Isolate* isolate, const byte* module_start,
                                 const byte* module_end, bool asm_js = false);
 
 }  // namespace testing
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_MODULE_H_