[wasm] Allocate a single script per wasm module

src/isolate.cc

 // Copyright 2012 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.
 
 #include "src/isolate.h"
 
 #include <stdlib.h>
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
@@ skipping 683 matching lines @@
     DCHECK(!fun->shared()->script()->IsScript());
 
     return stack_frame;
   }
 
   Handle<JSObject> NewStackFrameObject(WasmFrame* frame) {
     Handle<JSObject> stack_frame =
         factory()->NewJSObject(isolate_->object_function());
 
     if (!function_key_.is_null()) {
-      Handle<String> name = wasm::GetWasmFunctionName(
-          isolate_, handle(frame->wasm_instance(), isolate_),
-          frame->function_index());
+      // TODO(wasm): We should always have a wasm instance available (bug 5620).
+      Handle<Object> instance(frame->wasm_instance(), isolate_);
+      Handle<Object> compiled_module;
+      if (instance->IsUndefined(isolate_)) {
+        compiled_module = instance;  // undefined
+      } else {
+        compiled_module = handle(
+            wasm::GetCompiledModule(JSObject::cast(*instance)), isolate_);
+      }
+      Handle<String> name = wasm::GetWasmFunctionName(isolate_, compiled_module,
+                                                      frame->function_index());
       JSObject::AddProperty(stack_frame, function_key_, name, NONE);
     }
     // Encode the function index as line number.
     if (!line_key_.is_null()) {
       JSObject::AddProperty(
           stack_frame, line_key_,
           isolate_->factory()->NewNumberFromInt(frame->function_index()), NONE);
     }
     // Encode the byte offset as column.
     if (!column_key_.is_null()) {
@@ skipping 2772 matching lines @@
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8