Adds a flag to the standalone vm to throw an exception on 53-bit integer overflow.

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 23032)
+++ runtime/vm/object.cc	(working copy)
@@ -10386,6 +10386,17 @@
 }
 
 
+// Throw kFiftyThreeBitOverflow if the result of an operation overflows
+// 53 bits.
+void Integer::CheckForFiftyThreeBitOverflow(const Integer& i, const char* msg) {
+  if (i.FitsIn53Bits()) return;
+  const Array& exc_args = Array::Handle(Array::New(1));
+  exc_args.SetAt(0, Object::Handle(String::New(msg)));
+  Exceptions::ThrowByType(Exceptions::kFiftyThreeBitOverflowError, exc_args);
+  return;
+}
+
+
 double Integer::AsDoubleValue() const {
   UNIMPLEMENTED();
   return 0.0;
@@ -10398,6 +10409,12 @@
 }
 
 
+bool Integer::FitsIn53Bits() const {
+  UNIMPLEMENTED();
+  return false;
+}
+
+
 int Integer::CompareWith(const Integer& other) const {
   UNIMPLEMENTED();
   return 0;
@@ -10772,6 +10789,12 @@
 }
 
 
+bool Mint::FitsIn53Bits() const {
+  int64_t v = AsInt64Value();
+  return Utils::IsInt(53, v);
+}
+
+
 int Mint::CompareWith(const Integer& other) const {
   ASSERT(!FitsIntoSmi(*this));
   if (other.IsMint() || other.IsSmi()) {