VM: Support bootstrapping core libraries from Kernel binaries instead of source.

runtime/vm/intrinsifier_mips.cc

Index: runtime/vm/intrinsifier_mips.cc
diff --git a/runtime/vm/intrinsifier_mips.cc b/runtime/vm/intrinsifier_mips.cc
index aa512ad211b3fe290025346da25961f43a1970e9..4195bcf942c1dc966a9463659b04a5d6bf2d4528 100644
--- a/runtime/vm/intrinsifier_mips.cc
+++ b/runtime/vm/intrinsifier_mips.cc
@@ -1643,7 +1643,12 @@ void Intrinsifier::Random_nextState(Assembler* assembler) {
       random_class.LookupStaticFieldAllowPrivate(Symbols::_A()));
   ASSERT(!random_A_field.IsNull());
   ASSERT(random_A_field.is_const());
-  const Instance& a_value = Instance::Handle(random_A_field.StaticValue());
+  Instance& a_value = Instance::Handle(random_A_field.StaticValue());
+  if (a_value.raw() == Object::sentinel().raw() ||

[hausner, 2016/11/09 00:42:49]

Why is this additional check needed now?

[Vyacheslav Egorov (Google), 2016/11/09 14:43:16]

Due to front-end differences issues we might arrive here without evaluating the
initializer first (it's a pure coincidence that the field is initialized in the
source based front-end - we essentially rely on the fact that this field is
eagerly initialized which is not guaranteed in any way).

+      a_value.raw() == Object::transition_sentinel().raw()) {
+    random_A_field.EvaluateInitializer();
+    a_value = random_A_field.StaticValue();
+  }
   const int64_t a_int_value = Integer::Cast(a_value).AsInt64Value();
   // 'a_int_value' is a mask.
   ASSERT(Utils::IsUint(32, a_int_value));