Use Dart stack walker when we have an exit frame.

runtime/vm/profiler.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 "platform/utils.h"
 
 #include "vm/allocation.h"
 #include "vm/atomic.h"
 #include "vm/code_patcher.h"
 #include "vm/isolate.h"
@@ skipping 18 matching lines @@
 #endif
 DEFINE_FLAG(bool, trace_profiled_isolates, false, "Trace profiled isolates.");
 DEFINE_FLAG(charp, profile_dir, NULL,
             "Enable writing profile data into specified directory.");
 DEFINE_FLAG(int, profile_period, 1000,
             "Time between profiler samples in microseconds. Minimum 50.");
 DEFINE_FLAG(int, profile_depth, 8,
             "Maximum number stack frames walked. Minimum 1. Maximum 255.");
 DEFINE_FLAG(bool, profile_verify_stack_walk, false,
             "Verify instruction addresses while walking the stack.");
-DEFINE_FLAG(bool, profile_native_stack, true,
+DEFINE_FLAG(bool, profile_native_stack, false,
             "Use native stack in profiler.");
 
 bool Profiler::initialized_ = false;
 SampleBuffer* Profiler::sample_buffer_ = NULL;
 
 void Profiler::InitOnce() {
   // Place some sane restrictions on user controlled flags.
   SetSamplePeriod(FLAG_profile_period);
   SetSampleDepth(FLAG_profile_depth);
   if (!FLAG_profile) {
@@ skipping 1577 matching lines @@
 
 
 class ProfilerDartStackWalker : public ValueObject {
  public:
   explicit ProfilerDartStackWalker(Sample* sample)
       : sample_(sample),
         frame_iterator_() {
     ASSERT(sample_ != NULL);
   }
 
-  ProfilerDartStackWalker(Sample* sample, uword pc, uword fp, uword sp)
-      : sample_(sample),
-        frame_iterator_(fp, sp, pc) {
-    ASSERT(sample_ != NULL);
-  }
-
   ProfilerDartStackWalker(Sample* sample, uword fp)
       : sample_(sample),
         frame_iterator_(fp) {
     ASSERT(sample_ != NULL);
   }
 
   int walk() {
     intptr_t frame_index = 0;
     StackFrame* frame = frame_iterator_.NextFrame();
     while (frame != NULL) {
@@ skipping 184 matching lines @@
   SampleBuffer* sample_buffer = profiler_data->sample_buffer();
   if (sample_buffer == NULL) {
     return;
   }
   Sample* sample = sample_buffer->ReserveSample();
   sample->Init(isolate, OS::GetCurrentTimeMicros(), state.tid);
   sample->set_vm_tag(isolate->vm_tag());
   sample->set_user_tag(isolate->user_tag());
   sample->set_sp(state.sp);
   sample->set_fp(state.fp);
+
+  uword stack_lower = 0;
+  uword stack_upper = 0;
+  isolate->GetStackBounds(&stack_lower, &stack_upper);
+  if ((stack_lower == 0) || (stack_upper == 0)) {
+    stack_lower = 0;
+    stack_upper = 0;
+  }
   if (FLAG_profile_native_stack) {
     // Collect native and Dart frames.
-    uword stack_lower = 0;
-    uword stack_upper = 0;
-    isolate->GetStackBounds(&stack_lower, &stack_upper);
-    if ((stack_lower == 0) || (stack_upper == 0)) {
-      stack_lower = 0;
-      stack_upper = 0;
-    }
     ProfilerNativeStackWalker stackWalker(sample, stack_lower, stack_upper,
                                           state.pc, state.fp, state.sp);
     stackWalker.walk(isolate->heap());
-  } else {
-    if ((isolate->top_exit_frame_info() != 0) &&
-        (isolate->stub_code() != NULL)) {
+  } else if (isolate->stub_code() != NULL) {
+    if (isolate->top_exit_frame_info() != 0) {
       ProfilerDartStackWalker stackWalker(sample);
       stackWalker.walk();
     } else {
-      // TODO(johnmccutchan): Support collecting only Dart frames with
-      // ProfilerNativeStackWalker.
+      ProfilerNativeStackWalker stackWalker(sample, stack_lower, stack_upper,
+                                            state.pc, state.fp, state.sp);
+      stackWalker.walk(isolate->heap());
     }
   }

[siva, 2014/06/19 20:22:17]

Should there be an UNREACHEABLE() here, i.e you do not expect to record samples
before the stub code has been generated for the isolate.

[Cutch, 2014/06/23 17:30:12]

We want to collect samples during isolate start up.

 }
 
 }  // namespace dart