Fix static field initialization in optimzed DBC code.

runtime/vm/intermediate_language_dbc.cc

 // Copyright (c) 2016, 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_DBC.
 #if defined(TARGET_ARCH_DBC)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/cpu.h"
@@ skipping 400 matching lines @@
     __ LoadField(locs()->out(0).reg(),
                  locs()->in(0).reg(),
                  Field::static_value_offset() / kWordSize);
   } else {
     const intptr_t kidx = __ AddConstant(StaticField());
     __ PushStatic(kidx);
   }
 }
 
 
-EMIT_NATIVE_CODE(InitStaticField, 0) {
-  ASSERT(!compiler->is_optimizing());
-  __ InitStaticTOS();
+EMIT_NATIVE_CODE(InitStaticField, 1) {
+  if (compiler->is_optimizing()) {
+    __ Push(locs()->in(0).reg());
+    __ InitStaticTOS();

[Vyacheslav Egorov (Google), 2016/11/09 09:28:28]

This looks like a call. Does this need compiler->RecordAfterCall(this)?

[Florian Schneider, 2016/11/09 13:51:52]

Actually yes, good point. It could throw, or cause a lazy deopt. 

Will deopt still work with the input pushed on the stack, or do I have to add a
InitStaticFieldOpt bytecode that takes a register as input?

[Vyacheslav Egorov (Google), 2016/11/09 13:55:11]

I think it should work. 

Maybe write a test?

+  } else {
+    __ InitStaticTOS();
+  }
 }
 
 
 EMIT_NATIVE_CODE(ClosureCall,
                  1,
                  Location::RegisterLocation(0),
                  LocationSummary::kCall) {
   if (compiler->is_optimizing()) {
     __ Push(locs()->in(0).reg());
   }
@@ skipping 1532 matching lines @@
   __ IfULe(length, index);
   compiler->EmitDeopt(deopt_id(),
                       ICData::kDeoptCheckArrayBound,
                       (generalized_ ? ICData::kGeneralized : 0) |
                       (licm_hoisted_ ? ICData::kHoisted : 0));
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_DBC