Partially implement DBC profiler.

runtime/vm/profiler.cc

Index: runtime/vm/profiler.cc
diff --git a/runtime/vm/profiler.cc b/runtime/vm/profiler.cc
index ddd5b26817bfdea01f4dd4b7ff9d14ba51db6256..3509c4a54ba224f4a76c3d101c48524232b54362 100644
--- a/runtime/vm/profiler.cc
+++ b/runtime/vm/profiler.cc
@@ -529,7 +529,8 @@ class ProfilerDartStackWalker : public ProfilerStackWalker {
       return NextExit();
     }
     uword* new_fp = CallerFP();
-    if (new_fp <= fp_) {
+    if (!IsCalleeFrameOf(reinterpret_cast<uword>(new_fp),
+                         reinterpret_cast<uword>(fp_))) {
       // FP didn't move to a higher address.

[Cutch, 2016/08/19 13:49:31]

fix comment

[rmacnak, 2016/08/19 23:28:16]

Done.

       return false;
     }
@@ -837,8 +838,8 @@ static bool GetAndValidateIsolateStackBounds(Thread* thread,
   ASSERT(os_thread != NULL);
   ASSERT(stack_lower != NULL);
   ASSERT(stack_upper != NULL);
-#if defined(USING_SIMULATOR)
   const bool in_dart_code = thread->IsExecutingDartCode();
+#if defined(USING_SIMULATOR)
   if (in_dart_code) {
     Isolate* isolate = thread->isolate();
     ASSERT(isolate != NULL);
@@ -859,7 +860,8 @@ static bool GetAndValidateIsolateStackBounds(Thread* thread,
     return false;
   }
 #endif
-  if (sp > *stack_lower) {
+
+  if (!in_dart_code && sp > *stack_lower) {

[Cutch, 2016/08/19 13:49:31]

can this "!in_dart_code" be made DBC specific somehow?

[zra, 2016/08/19 15:40:08]

please add parens (sp > *stack_lower)

[rmacnak, 2016/08/19 23:28:16]

Done.

     // The stack pointer gives us a tighter lower bound.
     *stack_lower = sp;
   }
@@ -1125,11 +1127,6 @@ void Profiler::SampleThreadSingleFrame(Thread* thread, uintptr_t pc) {
 
 void Profiler::SampleThread(Thread* thread,
                             const InterruptedThreadState& state) {
-#if defined(TARGET_ARCH_DBC)
-  // TODO(vegorov) implement simulator stack sampling.
-  return;
-#endif
-
   ASSERT(thread != NULL);
   OSThread* os_thread = thread->os_thread();
   ASSERT(os_thread != NULL);
@@ -1155,14 +1152,17 @@ void Profiler::SampleThread(Thread* thread,
   uintptr_t sp = 0;
   uintptr_t fp = state.fp;
   uintptr_t pc = state.pc;
-#if defined(USING_SIMULATOR) && !defined(TARGET_ARCH_DBC)
+#if defined(USING_SIMULATOR)
   Simulator* simulator = NULL;
 #endif
 
   if (in_dart_code) {
     // If we're in Dart code, use the Dart stack pointer.
 #if defined(TARGET_ARCH_DBC)

[Cutch, 2016/08/19 13:49:31]

why not fold this into:

#if defined(TARGET_ARCH_DBC) || defined(USING_SIMULATOR)
simulator = isolate->simulator();
sp = ..
fp = ..
pc = ..
#else
...

[rmacnak, 2016/08/19 23:28:16]

DBC doesn't define Simulator::get_register.

-    UNIMPLEMENTED();
+    simulator = isolate->simulator();
+    sp = simulator->get_sp();
+    fp = simulator->get_fp();
+    pc = simulator->get_pc();
 #elif defined(USING_SIMULATOR)
     simulator = isolate->simulator();
     sp = simulator->get_register(SPREG);