[wasm][gc] Add code ref on NativeModule::GetCode

Since {NativeModule::GetCode} returns a raw pointer to {WasmCode}, it
needs to increment the reference counter on that code object.
{HasCode} on the other hand does not return a code pointer, so it's
implemented separately now.

R=mstarzinger@chromium.org

Bug: v8:8217
Change-Id: I812981aaf89281fb0296682114f248079e57a5e3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1566514Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60843}

src/runtime/runtime-test.cc

@@ -1226,6 +1226,7 @@ RUNTIME_FUNCTION(Runtime_IsLiftoffFunction) {
   wasm::NativeModule* native_module =
       exp_fun->instance()->module_object()->native_module();
   uint32_t func_index = exp_fun->function_index();
+  wasm::WasmCodeRefScope code_ref_scope;
   wasm::WasmCode* code = native_module->GetCode(func_index);
   return isolate->heap()->ToBoolean(code && code->is_liftoff());
 }

src/wasm/module-compiler.cc

@@ -626,7 +626,7 @@ void CompileLazy(Isolate* isolate, NativeModule* native_module,
 
   NativeModuleModificationScope native_module_modification_scope(native_module);
 
-  DCHECK(!native_module->has_code(static_cast<uint32_t>(func_index)));
+  DCHECK(!native_module->HasCode(static_cast<uint32_t>(func_index)));
 
   compilation_timer.Start();
 

src/wasm/wasm-code-manager.cc

@@ -835,6 +835,22 @@ std::vector<WasmCode*> NativeModule::SnapshotCodeTable() const {
   return std::vector<WasmCode*>{start, end};
 }
 
+WasmCode* NativeModule::GetCode(uint32_t index) const {
+  base::MutexGuard guard(&allocation_mutex_);
+  DCHECK_LT(index, num_functions());
+  DCHECK_LE(module_->num_imported_functions, index);
+  WasmCode* code = code_table_[index - module_->num_imported_functions];
+  WasmCodeRefScope::AddRef(code);
+  return code;
+}
+
+bool NativeModule::HasCode(uint32_t index) const {
+  base::MutexGuard guard(&allocation_mutex_);
+  DCHECK_LT(index, num_functions());
+  DCHECK_LE(module_->num_imported_functions, index);
+  return code_table_[index - module_->num_imported_functions] != nullptr;
+}
+
 WasmCode* NativeModule::CreateEmptyJumpTable(uint32_t jump_table_size) {
   // Only call this if we really need a jump table.
   DCHECK_LT(0, jump_table_size);

src/wasm/wasm-code-manager.h

@@ -319,14 +319,8 @@ class V8_EXPORT_PRIVATE NativeModule final {
   // to get a consistent view of the table (e.g. used by the serializer).
   std::vector<WasmCode*> SnapshotCodeTable() const;
 
-  WasmCode* GetCode(uint32_t index) const {
-    base::MutexGuard guard(&allocation_mutex_);
-    DCHECK_LT(index, num_functions());
-    DCHECK_LE(module_->num_imported_functions, index);
-    return code_table_[index - module_->num_imported_functions];
-  }
-
-  bool has_code(uint32_t index) const { return GetCode(index) != nullptr; }
+  WasmCode* GetCode(uint32_t index) const;
+  bool HasCode(uint32_t index) const;
 
   Address runtime_stub_entry(WasmCode::RuntimeStubId index) const {
     DCHECK_LT(index, WasmCode::kRuntimeStubCount);