Fixes for the profiler on arm64.

runtime/vm/signal_handler_macos.cc

Index: runtime/vm/signal_handler_macos.cc
===================================================================
--- runtime/vm/signal_handler_macos.cc	(revision 40496)
+++ runtime/vm/signal_handler_macos.cc	(working copy)
@@ -20,6 +20,8 @@
   pc = static_cast<uintptr_t>(mcontext->__ss.__eip);
 #elif defined(TARGET_ARCH_ARM) && defined(USING_SIMULATOR)
   pc = static_cast<uintptr_t>(mcontext->__ss.__eip);
+#elif defined(TARGET_ARCH_ARM64) && defined(USING_SIMULATOR)
+  pc = static_cast<uintptr_t>(mcontext->__ss.__rip);
 #else
   UNIMPLEMENTED();
 #endif  // TARGET_ARCH_...
@@ -39,6 +41,8 @@
   fp = static_cast<uintptr_t>(mcontext->__ss.__ebp);
 #elif defined(TARGET_ARCH_ARM) && defined(USING_SIMULATOR)
   fp = static_cast<uintptr_t>(mcontext->__ss.__ebp);
+#elif defined(TARGET_ARCH_ARM64) && defined(USING_SIMULATOR)
+  fp = static_cast<uintptr_t>(mcontext->__ss.__rbp);
 #else
   UNIMPLEMENTED();
 #endif  // TARGET_ARCH_...
@@ -47,7 +51,7 @@
 }
 
 
-uintptr_t SignalHandler::GetStackPointer(const mcontext_t& mcontext) {
+uintptr_t SignalHandler::GetCStackPointer(const mcontext_t& mcontext) {
   uintptr_t sp = 0;
 
 #if defined(TARGET_ARCH_IA32)
@@ -58,6 +62,8 @@
   sp = static_cast<uintptr_t>(mcontext->__ss.__esp);
 #elif defined(TARGET_ARCH_ARM) && defined(USING_SIMULATOR)
   sp = static_cast<uintptr_t>(mcontext->__ss.__esp);
+#elif defined(TARGET_ARCH_ARM64) && defined(USING_SIMULATOR)
+  sp = static_cast<uintptr_t>(mcontext->__ss.__rsp);
 #else
   UNIMPLEMENTED();
 #endif  // TARGET_ARCH_...
@@ -66,6 +72,11 @@
 }
 
 
+uintptr_t SignalHandler::GetDartStackPointer(const mcontext_t& mcontext) {
+  return GetCStackPointer(mcontext);
+}
+
+
 void SignalHandler::Install(SignalAction action) {
   struct sigaction act;
   act.sa_handler = NULL;