DBC: Enables unboxed doubles

runtime/vm/deopt_instructions.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/deopt_instructions.h"
 
 #include "vm/assembler.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
 #include "vm/intermediate_language.h"
@@ skipping 1104 matching lines @@
       }
       case kUnboxedInt32:
         deopt_instr = new(zone()) DeoptInt32Instr(
             ToCpuRegisterSource(source_loc));
         break;
       case kUnboxedUint32:
         deopt_instr = new(zone()) DeoptUint32Instr(
             ToCpuRegisterSource(source_loc));
         break;
       case kUnboxedDouble:
+#if !defined(TARGET_ARCH_DBC)
         deopt_instr = new(zone()) DeoptDoubleInstr(
             ToFpuRegisterSource(source_loc, Location::kDoubleStackSlot));
+#else
+        // DBC stores unboxed doubles in regular registers (i.e. stack slots).
+        deopt_instr = new(zone()) DeoptWordInstr(

[Vyacheslav Egorov (Google), 2016/07/14 16:26:24]

This seems incorrect. DeoptDoubleInstr takes care of materializing Double object
on deoptimization. DeoptWorkInstr would not do it. It just copies things as is.

Please write some microtest that deoptimizes with unboxed double to verify that
it is materialized correctly.

[zra, 2016/07/14 21:12:10]

Done.

+            ToCpuRegisterSource(source_loc));
+#endif
         break;
       case kUnboxedFloat32x4:
         deopt_instr = new(zone()) DeoptFloat32x4Instr(
             ToFpuRegisterSource(source_loc, Location::kQuadStackSlot));
         break;
       case kUnboxedFloat64x2:
         deopt_instr = new(zone()) DeoptFloat64x2Instr(
             ToFpuRegisterSource(source_loc, Location::kQuadStackSlot));
         break;
       case kUnboxedInt32x4:
@@ skipping 203 matching lines @@
                           Smi* offset,
                           TypedData* info,
                           Smi* reason) {
   intptr_t i = index * kEntrySize;
   *offset ^= table.At(i);
   *info ^= table.At(i + 1);
   *reason ^= table.At(i + 2);
 }
 
 }  // namespace dart