Add support for javascript incompatibility warnings.

runtime/lib/object.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/bootstrap_natives.h"
 
 #include "lib/invocation_mirror.h"
+#include "vm/code_patcher.h"
 #include "vm/exceptions.h"
 #include "vm/heap.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, trace_type_checks);
+DECLARE_FLAG(bool, warn_on_javascript_compatibility);
 
 
 DEFINE_NATIVE_ENTRY(Object_equals, 1) {
   // Implemented in the flow graph builder.
   UNREACHABLE();
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(Object_cid, 1) {
@@ skipping 73 matching lines @@
 
 
 DEFINE_NATIVE_ENTRY(Object_runtimeType, 1) {
   const Instance& instance = Instance::CheckedHandle(arguments->NativeArgAt(0));
   // Special handling for following types outside this native.
   ASSERT(!instance.IsString() && !instance.IsInteger() && !instance.IsDouble());
   return instance.GetType();
 }
 
 
+static void JSWarning(const char* msg) {
+  DartFrameIterator iterator;
+  iterator.NextFrame();  // Skip native call.
+  StackFrame* caller_frame = iterator.NextFrame();
+  ASSERT(caller_frame != NULL);
+  const Code& caller_code = Code::Handle(caller_frame->LookupDartCode());
+  ASSERT(!caller_code.IsNull());
+  const uword caller_pc = caller_frame->pc();
+  // Assume an instance call.
+  ICData& ic_data = ICData::Handle();
+  CodePatcher::GetInstanceCallAt(caller_pc, caller_code, &ic_data);
+  ASSERT(!ic_data.IsNull());
+  // Report warning only if not already reported at this location.
+  if (!ic_data.IssuedJSWarning()) {
+    ic_data.SetIssuedJSWarning();
+    Exceptions::JSWarning(caller_frame, "%s", msg);
+  }
+}
+
+
+static void WarnOnJSIntegralNumTypeTest(
+    const Instance& instance,
+    const TypeArguments& instantiator_type_arguments,
+    const AbstractType& type) {
+  const bool instance_is_int = instance.IsInteger();
+  const bool instance_is_double = instance.IsDouble();
+  if (!(instance_is_int || instance_is_double)) {
+    return;
+  }
+  AbstractType& instantiated_type = AbstractType::Handle(type.raw());
+  if (!type.IsInstantiated()) {
+    instantiated_type = type.InstantiateFrom(instantiator_type_arguments, NULL);
+  }
+  if (instance_is_double) {
+    if (instantiated_type.IsIntType()) {
+      const double value = Double::Cast(instance).value();
+      if (floor(value) == value) {
+        JSWarning("integral value of type 'double' is also considered to be "
+                  "of type 'int'");
+      }
+    }
+  } else {
+    ASSERT(instance_is_int);
+    if (instantiated_type.IsDoubleType()) {
+      JSWarning("integer value is also considered to be of type 'double'");
+    }
+  }
+}
+
+
 DEFINE_NATIVE_ENTRY(Object_instanceOf, 5) {
   const Instance& instance = Instance::CheckedHandle(arguments->NativeArgAt(0));
   // Instantiator at position 1 is not used. It is passed along so that the call
   // can be easily converted to an optimized implementation. Instantiator is
   // used to populate the subtype cache.
   const TypeArguments& instantiator_type_arguments =
       TypeArguments::CheckedHandle(arguments->NativeArgAt(2));
   const AbstractType& type =
       AbstractType::CheckedHandle(arguments->NativeArgAt(3));
   const Bool& negate = Bool::CheckedHandle(arguments->NativeArgAt(4));
   ASSERT(type.IsFinalized());
   ASSERT(!type.IsMalformed());
   ASSERT(!type.IsMalbounded());
+
+  // Check for javascript compatibility.
+  if (FLAG_warn_on_javascript_compatibility) {
+    WarnOnJSIntegralNumTypeTest(instance, instantiator_type_arguments, type);
+  }
+
   Error& bound_error = Error::Handle();
   const bool is_instance_of = instance.IsInstanceOf(type,
                                                     instantiator_type_arguments,
                                                     &bound_error);
   if (FLAG_trace_type_checks) {
     const char* result_str = is_instance_of ? "true" : "false";
     OS::Print("Native Object.instanceOf: result %s\n", result_str);
     const Type& instance_type = Type::Handle(instance.GetType());
     OS::Print("  instance type: %s\n",
               String::Handle(instance_type.Name()).ToCString());
@@ skipping 28 matching lines @@
       TypeArguments::CheckedHandle(arguments->NativeArgAt(2));
   const AbstractType& type =
       AbstractType::CheckedHandle(arguments->NativeArgAt(3));
   ASSERT(type.IsFinalized());
   ASSERT(!type.IsMalformed());
   ASSERT(!type.IsMalbounded());
   Error& bound_error = Error::Handle();
   if (instance.IsNull()) {
     return instance.raw();
   }
+
+  // Check for javascript compatibility.
+  if (FLAG_warn_on_javascript_compatibility) {
+    WarnOnJSIntegralNumTypeTest(instance, instantiator_type_arguments, type);
+  }
+
   const bool is_instance_of = instance.IsInstanceOf(type,
                                                     instantiator_type_arguments,
                                                     &bound_error);
   if (FLAG_trace_type_checks) {
     const char* result_str = is_instance_of ? "true" : "false";
     OS::Print("Object.as: result %s\n", result_str);
     const Type& instance_type = Type::Handle(instance.GetType());
     OS::Print("  instance type: %s\n",
               String::Handle(instance_type.Name()).ToCString());
     OS::Print("  cast type: %s\n", String::Handle(type.Name()).ToCString());
@@ skipping 49 matching lines @@
 
 
 DEFINE_NATIVE_ENTRY(LibraryPrefix_load, 1) {
   const LibraryPrefix& prefix =
       LibraryPrefix::CheckedHandle(arguments->NativeArgAt(0));
   prefix.LoadLibrary();
   return Bool::Get(true).raw();
 }
 
 }  // namespace dart