[wasm] Cleanup unneeded casts to WasmInstanceObject

src/runtime/runtime-wasm.cc

 // Copyright 2016 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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/assembler.h"
 #include "src/compiler/wasm-compiler.h"
 #include "src/conversions.h"
 #include "src/debug/debug.h"
 #include "src/factory.h"
 #include "src/frames-inl.h"
 #include "src/objects-inl.h"
 #include "src/v8memory.h"
 #include "src/wasm/wasm-module.h"
 #include "src/wasm/wasm-objects.h"
 #include "src/wasm/wasm-opcodes.h"
 
 namespace v8 {
 namespace internal {
 
+namespace {
+Handle<WasmInstanceObject> GetWasmInstanceOnStackTop(Isolate* isolate) {
+  DisallowHeapAllocation no_allocation;
+  const Address entry = Isolate::c_entry_fp(isolate->thread_local_top());
+  Address pc =
+      Memory::Address_at(entry + StandardFrameConstants::kCallerPCOffset);
+  Code* code = isolate->inner_pointer_to_code_cache()->GetCacheEntry(pc)->code;
+  DCHECK_EQ(Code::WASM_FUNCTION, code->kind());
+  WasmInstanceObject* owning_instance = wasm::GetOwningWasmInstance(code);
+  CHECK_NOT_NULL(owning_instance);
+  return handle(owning_instance, isolate);
+}
+}  // namespace
+
 RUNTIME_FUNCTION(Runtime_WasmMemorySize) {
   HandleScope scope(isolate);
   DCHECK_EQ(0, args.length());
 
-  Handle<WasmInstanceObject> instance;
-  {
-    // Get the module JSObject
-    DisallowHeapAllocation no_allocation;
-    const Address entry = Isolate::c_entry_fp(isolate->thread_local_top());
-    Address pc =
-        Memory::Address_at(entry + StandardFrameConstants::kCallerPCOffset);
-    Code* code =
-        isolate->inner_pointer_to_code_cache()->GetCacheEntry(pc)->code;
-    WasmInstanceObject* owning_instance = wasm::GetOwningWasmInstance(code);
-    CHECK_NOT_NULL(owning_instance);
-    instance = handle(owning_instance, isolate);
-  }
+  Handle<WasmInstanceObject> instance = GetWasmInstanceOnStackTop(isolate);
   return *isolate->factory()->NewNumberFromInt(
       wasm::GetInstanceMemorySize(isolate, instance));
 }
 
 RUNTIME_FUNCTION(Runtime_WasmGrowMemory) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_UINT32_ARG_CHECKED(delta_pages, 0);
-  Handle<WasmInstanceObject> instance;
-  {
-    // Get the module JSObject
-    DisallowHeapAllocation no_allocation;
-    const Address entry = Isolate::c_entry_fp(isolate->thread_local_top());
-    Address pc =
-        Memory::Address_at(entry + StandardFrameConstants::kCallerPCOffset);
-    Code* code =
-        isolate->inner_pointer_to_code_cache()->GetCacheEntry(pc)->code;
-    WasmInstanceObject* owning_instance = wasm::GetOwningWasmInstance(code);
-    CHECK_NOT_NULL(owning_instance);
-    instance = handle(owning_instance, isolate);
-  }
+  Handle<WasmInstanceObject> instance = GetWasmInstanceOnStackTop(isolate);
   return *isolate->factory()->NewNumberFromInt(
       wasm::GrowMemory(isolate, instance, delta_pages));
 }
 
 Object* ThrowRuntimeError(Isolate* isolate, int message_id, int byte_offset,
                           bool patch_source_position) {
   HandleScope scope(isolate);
   Handle<Object> error_obj = isolate->factory()->NewWasmRuntimeError(
       static_cast<MessageTemplate::Template>(message_id));
 
@@ skipping 86 matching lines @@
   Object* exception = args[0];
   // The unwinder will only deliver exceptions to wasm if the exception is a
   // Number or a Smi (which we have just converted to a Number.) This logic
   // lives in Isolate::is_catchable_by_wasm(Object*).
   CHECK(exception->IsNumber());
   return exception;
 }
 
 }  // namespace internal
 }  // namespace v8