[wasm] Stack inspection support for asm.js frames

src/wasm/wasm-module.cc

 // 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.
 
 #include <memory>
 
 #include "src/base/atomic-utils.h"
 #include "src/code-stubs.h"
 
 #include "src/macro-assembler.h"
@@ skipping 1366 matching lines @@
     ProcessExports(globals, code_table, instance);
 
     if (num_imported_functions > 0 || !owner.is_null()) {
       // If the code was cloned, or new imports were compiled, patch.
       PatchDirectCalls(old_code_table, code_table, num_imported_functions);
     }
 
     FlushICache(isolate_, code_table);
 
     //--------------------------------------------------------------------------
-    // Run the start function if one was specified.
+    // Set up and link the new instance.
     //--------------------------------------------------------------------------
-    if (compiled_module_->has_startup_function()) {
-      Handle<FixedArray> startup_data = compiled_module_->startup_function();
-      HandleScope scope(isolate_);
-      int32_t start_index =
-          startup_data->GetValueChecked<Smi>(isolate_, kExportIndex)->value();
-      Handle<Code> startup_code =
-          code_table->GetValueChecked<Code>(isolate_, start_index);
-      int arity = Smi::cast(startup_data->get(kExportArity))->value();
-      MaybeHandle<ByteArray> startup_signature =
-          startup_data->GetValue<ByteArray>(isolate_, kExportedSignature);
-      Handle<JSFunction> startup_fct = WrapExportCodeAsJSFunction(
-          isolate_, startup_code, factory->InternalizeUtf8String("start"),
-          arity, startup_signature, instance);
-      RecordStats(isolate_, *startup_code);
-      // Call the JS function.
-      Handle<Object> undefined = factory->undefined_value();
-      MaybeHandle<Object> retval =
-          Execution::Call(isolate_, startup_fct, undefined, 0, nullptr);
-
-      if (retval.is_null()) {
-        thrower_->Error("WASM.instantiateModule(): start function failed");
-        return nothing;
-      }
-    }
-
     {
       Handle<Object> global_handle =
           isolate_->global_handles()->Create(*instance);
       Handle<WeakCell> link_to_clone = factory->NewWeakCell(compiled_module_);
       Handle<WeakCell> link_to_owning_instance = factory->NewWeakCell(instance);
       MaybeHandle<WeakCell> link_to_original;
       MaybeHandle<WasmCompiledModule> original;
       if (!owner.is_null()) {
         // prepare the data needed for publishing in a chain, but don't link
         // just yet, because
@@ skipping 15 matching lines @@
         }
         module_object_->SetInternalField(0, *compiled_module_);
         instance->SetInternalField(kWasmCompiledModule, *compiled_module_);
         compiled_module_->set_weak_owning_instance(link_to_owning_instance);
         GlobalHandles::MakeWeak(global_handle.location(),
                                 global_handle.location(), &InstanceFinalizer,
                                 v8::WeakCallbackType::kFinalizer);
       }
     }
 
+    //--------------------------------------------------------------------------
+    // Run the start function if one was specified.
+    //--------------------------------------------------------------------------
+    if (compiled_module_->has_startup_function()) {
+      Handle<FixedArray> startup_data = compiled_module_->startup_function();
+      HandleScope scope(isolate_);
+      int32_t start_index =
+          startup_data->GetValueChecked<Smi>(isolate_, kExportIndex)->value();
+      Handle<Code> startup_code =
+          code_table->GetValueChecked<Code>(isolate_, start_index);
+      int arity = Smi::cast(startup_data->get(kExportArity))->value();
+      MaybeHandle<ByteArray> startup_signature =
+          startup_data->GetValue<ByteArray>(isolate_, kExportedSignature);
+      Handle<JSFunction> startup_fct = WrapExportCodeAsJSFunction(
+          isolate_, startup_code, factory->InternalizeUtf8String("start"),
+          arity, startup_signature, instance);
+      RecordStats(isolate_, *startup_code);
+      // Call the JS function.
+      Handle<Object> undefined = factory->undefined_value();
+      MaybeHandle<Object> retval =
+          Execution::Call(isolate_, startup_fct, undefined, 0, nullptr);
+
+      if (retval.is_null()) {
+        thrower_->Error("WASM.instantiateModule(): start function failed");
+        // It's unfortunate that the new instance is already linked in the
+        // chain. However, we need to set up everything before executing the
+        // start function, such that stack trace information can be generated
+        // correctly already in the start function.
+        return nothing;
+      }
+    }
+
     DCHECK(wasm::IsWasmObject(*instance));
 
     TRACE("Finishing instance %d\n", compiled_module_->instance_id());
     TRACE_CHAIN(WasmCompiledModule::cast(module_object_->GetInternalField(0)));
     return instance;
   }
 
  private:
   Isolate* isolate_;
   ErrorThrower* thrower_;
@@ skipping 854 matching lines @@
   CHECK(IsWasmObject(*instance));
   WasmCompiledModule* compiled_module = GetCompiledModule(*instance);
   CHECK(compiled_module->has_weak_module_object());
   CHECK(compiled_module->ptr_to_weak_module_object()->cleared());
 }
 
 }  // namespace testing
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8