Improve internal compiler API so that OSR code is never installed on function.

runtime/lib/mirrors.cc

 // Copyright (c) 2012, 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 "lib/mirrors.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
@@ skipping 78 matching lines @@
 
   Thread* thread = Thread::Current();
   Zone* zone = thread->zone();
   const Class& cls = Class::Handle(zone, func.Owner());
   const Error& error = Error::Handle(zone, cls.EnsureIsFinalized(thread));
   if (!error.IsNull()) {
     Exceptions::PropagateError(error);
     UNREACHABLE();
   }
   if (!func.HasCode()) {
-    const Error& error =
-        Error::Handle(zone, Compiler::CompileFunction(thread, func));
-    if (!error.IsNull()) {
-      Exceptions::PropagateError(error);
+    const Object& result =

[Vyacheslav Egorov (Google), 2017/03/30 09:58:52]

There are a lot of places that do this. Maybe you need a helper?

Compile::EnsureCode(thread, func) {
  // ...  
}

notice that returning Null in such places is also an error - so maybe assert
that it does not happen. We expect to have code attached to the function after
this invocation.

Maybe even put something on the function itself:

Function::EnsureCode() {
 if (func.HasCode()) return;
 ...
}

[erikcorry, 2017/03/30 12:26:33]

Done.

+        Object::Handle(zone, Compiler::CompileFunction(thread, func));
+    if (result.IsError()) {
+      Exceptions::PropagateError(Error::Cast(result));
       UNREACHABLE();
     }
   }
 }
 
 static RawInstance* CreateParameterMirrorList(const Function& func,
                                               const Instance& owner_mirror) {
   HANDLESCOPE(Thread::Current());
   const intptr_t implicit_param_count = func.NumImplicitParameters();
   const intptr_t non_implicit_param_count =
@@ skipping 1981 matching lines @@
 
 DEFINE_NATIVE_ENTRY(TypeMirror_subtypeTest, 2) {
   GET_NON_NULL_NATIVE_ARGUMENT(AbstractType, a, arguments->NativeArgAt(0));
   GET_NON_NULL_NATIVE_ARGUMENT(AbstractType, b, arguments->NativeArgAt(1));
   return Bool::Get(a.IsSubtypeOf(b, NULL, NULL, Heap::kNew)).raw();
 }
 
 #endif  // !PRODUCT && !DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart