[vm, gardening] Move --trace-service output to stderr.

runtime/vm/thread.cc

 // Copyright (c) 2015, 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/thread.h"
 
 #include "vm/compiler_stats.h"
 #include "vm/dart_api_state.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
@@ skipping 492 matching lines @@
 
     // Clear deferrable interrupts, if present.
     stack_limit_ &= ~deferred_interrupts_mask_;
 
     if ((stack_limit_ & kInterruptsMask) == 0) {
       // No other pending interrupts.  Restore normal stack limit.
       stack_limit_ = saved_stack_limit_;
     }
   }
   if (FLAG_trace_service && FLAG_trace_service_verbose) {
-    OS::Print("[+%" Pd64 "ms] Isolate %s deferring OOB interrupts\n",
-              Dart::UptimeMillis(), isolate()->name());
+    OS::PrintErr("[+%" Pd64 "ms] Isolate %s deferring OOB interrupts\n",
+                 Dart::UptimeMillis(), isolate()->name());
   }
 }
 
 void Thread::RestoreOOBMessageInterrupts() {
   MonitorLocker ml(thread_lock_);
   defer_oob_messages_count_--;
   if (defer_oob_messages_count_ > 0) {
     return;
   }
   ASSERT(defer_oob_messages_count_ == 0);
   ASSERT(deferred_interrupts_mask_ == kMessageInterrupt);
   deferred_interrupts_mask_ = 0;
   if (deferred_interrupts_ != 0) {
     if (stack_limit_ == saved_stack_limit_) {
       stack_limit_ = kInterruptStackLimit & ~kInterruptsMask;
     }
     stack_limit_ |= deferred_interrupts_;
     deferred_interrupts_ = 0;
   }
   if (FLAG_trace_service && FLAG_trace_service_verbose) {
-    OS::Print("[+%" Pd64 "ms] Isolate %s restoring OOB interrupts\n",
-              Dart::UptimeMillis(), isolate()->name());
+    OS::PrintErr("[+%" Pd64 "ms] Isolate %s restoring OOB interrupts\n",
+                 Dart::UptimeMillis(), isolate()->name());
   }
 }
 
 RawError* Thread::HandleInterrupts() {
   uword interrupt_bits = GetAndClearInterrupts();
   if ((interrupt_bits & kVMInterrupt) != 0) {
     if (isolate()->store_buffer()->Overflowed()) {
       if (FLAG_verbose_gc) {
         OS::PrintErr("Scavenge scheduled by store buffer overflow.\n");
       }
@@ skipping 312 matching lines @@
 
 DisableThreadInterruptsScope::~DisableThreadInterruptsScope() {
   if (thread() != NULL) {
     OSThread* os_thread = thread()->os_thread();
     ASSERT(os_thread != NULL);
     os_thread->EnableThreadInterrupts();
   }
 }
 
 }  // namespace dart