Add support for javascript incompatibility warnings.

runtime/vm/code_generator.cc

 // Copyright (c) 2013, 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/code_generator.h"
 
 #include "vm/assembler.h"
 #include "vm/ast.h"
 #include "vm/bigint_operations.h"
 #include "vm/code_patcher.h"
@@ skipping 38 matching lines @@
     "Trace IC miss in optimized code");
 DEFINE_FLAG(bool, trace_optimized_ic_calls, false,
     "Trace IC calls in optimized code.");
 DEFINE_FLAG(bool, trace_patching, false, "Trace patching of code.");
 DEFINE_FLAG(bool, trace_runtime_calls, false, "Trace runtime calls");
 DEFINE_FLAG(bool, trace_type_checks, false, "Trace runtime type checks.");
 
 DECLARE_FLAG(int, deoptimization_counter_threshold);
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, report_usage_count);
+DECLARE_FLAG(bool, warn_on_javascript_compatibility);
 
 DEFINE_FLAG(bool, use_osr, true, "Use on-stack replacement.");
 DEFINE_FLAG(bool, trace_osr, false, "Trace attempts at on-stack replacement.");
 
 DEFINE_FLAG(int, stacktrace_every, 0,
             "Compute debugger stacktrace on every N stack overflow checks");
 DEFINE_FLAG(charp, stacktrace_filter, NULL,
             "Compute stacktrace in named function on stack overflow checks");
 DEFINE_FLAG(int, deoptimize_every, 0,
             "Deoptimize on every N stack overflow checks");
@@ skipping 711 matching lines @@
           caller_frame->pc(),
           Class::Handle(receiver.clazz()).ToCString(),
           receiver.GetClassId(),
           target_function.ToCString());
     }
   }
   return target_function.raw();
 }
 
 
-// Handles inline cache misses by updating the IC data array of the call
-// site.
+static void JSWarning(const ICData& ic_data, const char* msg) {
+  DartFrameIterator iterator;
+  StackFrame* caller_frame = iterator.NextFrame();
+  ASSERT(caller_frame != NULL);
+  // Report warning only if not already reported at this location.
+  if (!ic_data.IssuedJSWarning()) {
+    ic_data.SetIssuedJSWarning();
+    Exceptions::JSWarning(caller_frame, "%s", msg);
+  }
+}
+
+
+// Handles inline cache misses by updating the IC data array of the call site.
 //   Arg0: Receiver object.
 //   Arg1: IC data object.
 //   Returns: target function with compiled code or null.
 // Modifies the instance call to hold the updated IC data array.
 DEFINE_RUNTIME_ENTRY(InlineCacheMissHandlerOneArg, 2) {
   const Instance& receiver = Instance::CheckedHandle(arguments.ArgAt(0));
   const ICData& ic_data = ICData::CheckedHandle(arguments.ArgAt(1));
   GrowableArray<const Instance*> args(1);
   args.Add(&receiver);
+  if (FLAG_warn_on_javascript_compatibility) {
+    if (receiver.IsDouble() &&
+        String::Handle(ic_data.target_name()).Equals(Symbols::toString())) {
+      const double value = Double::Cast(receiver).value();
+      if (floor(value) == value) {
+        JSWarning(ic_data,
+                  "string representation of an integral value of type "
+                  "'double' has no decimal mark and no fractional part");
+      }
+    }
+  }
   const Function& result =
       Function::Handle(InlineCacheMissHandler(args, ic_data));
   arguments.SetReturn(result);
 }
 
 
-// Handles inline cache misses by updating the IC data array of the call
-// site.
+// Handles inline cache misses by updating the IC data array of the call site.
 //   Arg0: Receiver object.
 //   Arg1: Argument after receiver.
 //   Arg2: IC data object.
 //   Returns: target function with compiled code or null.
 // Modifies the instance call to hold the updated IC data array.
 DEFINE_RUNTIME_ENTRY(InlineCacheMissHandlerTwoArgs, 3) {
   const Instance& receiver = Instance::CheckedHandle(arguments.ArgAt(0));
   const Instance& other = Instance::CheckedHandle(arguments.ArgAt(1));
   const ICData& ic_data = ICData::CheckedHandle(arguments.ArgAt(2));
   GrowableArray<const Instance*> args(2);
   args.Add(&receiver);
   args.Add(&other);
   const Function& result =
       Function::Handle(InlineCacheMissHandler(args, ic_data));
   arguments.SetReturn(result);
 }
 
 
-// Handles inline cache misses by updating the IC data array of the call
-// site.
+// Handles inline cache misses by updating the IC data array of the call site.
 //   Arg0: Receiver object.
 //   Arg1: Argument after receiver.
 //   Arg2: Second argument after receiver.
 //   Arg3: IC data object.
 //   Returns: target function with compiled code or null.
 // Modifies the instance call to hold the updated IC data array.
 DEFINE_RUNTIME_ENTRY(InlineCacheMissHandlerThreeArgs, 4) {
   const Instance& receiver = Instance::CheckedHandle(arguments.ArgAt(0));
   const Instance& arg1 = Instance::CheckedHandle(arguments.ArgAt(1));
   const Instance& arg2 = Instance::CheckedHandle(arguments.ArgAt(2));
@@ skipping 658 matching lines @@
 // of the given value.
 //   Arg0: Field object;
 //   Arg1: Value that is being stored.
 DEFINE_RUNTIME_ENTRY(UpdateFieldCid, 2) {
   const Field& field = Field::CheckedHandle(arguments.ArgAt(0));
   const Object& value = Object::Handle(arguments.ArgAt(1));
   field.UpdateGuardedCidAndLength(value);
 }
 
 }  // namespace dart