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

runtime/vm/intrinsifier_mips.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/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 1625 matching lines @@
   const Class& random_class = Class::Handle(
       math_lib.LookupClassAllowPrivate(Symbols::_Random()));
   ASSERT(!random_class.IsNull());
   const Field& state_field = Field::ZoneHandle(
       random_class.LookupInstanceFieldAllowPrivate(Symbols::_state()));
   ASSERT(!state_field.IsNull());
   const Field& random_A_field = Field::ZoneHandle(
       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));
   int32_t a_int32_value = static_cast<int32_t>(a_int_value);
 
   // Receiver.
   __ lw(T0, Address(SP, 0 * kWordSize));
   // Field '_state'.
   __ lw(T1, FieldAddress(T0, state_field.Offset()));
 
@@ skipping 748 matching lines @@
   __ lw(T0, Address(V0, TimelineStream::enabled_offset()));
   __ LoadObject(V0, Bool::True());
   __ LoadObject(V1, Bool::False());
   __ Ret();
   __ delay_slot()->movz(V0, V1, T0);  // V0 = (T0 == 0) ? V1 : V0.
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS