Print messages when aborting background compilation (--trace-compiler); turn on background compilat…

runtime/vm/intermediate_language_x64.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_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/compiler.h"
@@ skipping 1435 matching lines @@
 
 void GuardFieldClassInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   ASSERT(sizeof(classid_t) == kInt32Size);
   const intptr_t value_cid = value()->Type()->ToCid();
   const intptr_t field_cid = field().guarded_cid();
   const intptr_t nullability = field().is_nullable() ? kNullCid : kIllegalCid;
 
   if (field_cid == kDynamicCid) {
     if (Compiler::IsBackgroundCompilation()) {
       // Field state changed while compiling.
-      Compiler::AbortBackgroundCompilation(deopt_id());
+      Compiler::AbortBackgroundCompilation(deopt_id(),
+          "GuardFieldClassInstr: field state changed while compiling");
     }
     ASSERT(!compiler->is_optimizing());
     return;  // Nothing to emit.
   }
 
   const bool emit_full_guard =
       !compiler->is_optimizing() || (field_cid == kIllegalCid);
 
   const bool needs_value_cid_temp_reg =
       (value_cid == kDynamicCid) && (emit_full_guard || (field_cid != kSmiCid));
@@ skipping 124 matching lines @@
     return summary;
   }
   UNREACHABLE();
 }
 
 
 void GuardFieldLengthInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   if (field().guarded_list_length() == Field::kNoFixedLength) {
     if (Compiler::IsBackgroundCompilation()) {
       // Field state changed while compiling.
-      Compiler::AbortBackgroundCompilation(deopt_id());
+      Compiler::AbortBackgroundCompilation(deopt_id(),
+          "GuardFieldLengthInstr: field state changed while compiling");
     }
     ASSERT(!compiler->is_optimizing());
     return;  // Nothing to emit.
   }
 
   Label* deopt = compiler->is_optimizing() ?
       compiler->AddDeoptStub(deopt_id(), ICData::kDeoptGuardField) : NULL;
 
   const Register value_reg = locs()->in(0).reg();
 
@@ skipping 4913 matching lines @@
   __ Drop(1);
   __ popq(result);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64