DWARF and unwind support for AOT assembly output.

runtime/vm/flags.cc

Index: runtime/vm/flags.cc
diff --git a/runtime/vm/flags.cc b/runtime/vm/flags.cc
index dad1410a53f5b7a587e8d143766e2761a853f6f2..9bb5eeb8f878290be41c71f0faf9e28ae94fad1e 100644
--- a/runtime/vm/flags.cc
+++ b/runtime/vm/flags.cc
@@ -440,10 +440,20 @@ bool Flags::ProcessCommandLineFlags(int number_of_vm_flags,
     PrintFlags();
   }
 
+  if (FLAG_dwarf_stack_traces) {
+    // The Dart standard requires the output of StackTrace.toString to include
+    // all pending activations with precise source locations (i.e., to expand
+    // inlined frames and provide line and column numbers).
+    OS::PrintErr(
+        "Warning: This VM has been configured to produce stack traces "

[Cutch, 2017/03/15 14:54:13]

Is this necessary?

[rmacnak, 2017/03/16 17:50:11]

Maybe in the stack trace instead, but we should be clear the VM isn't running
Dart with this flag.

+        "that violate the Dart standard.\n");
+  }
+
   initialized_ = true;
   return true;
 }
 
+
 bool Flags::SetFlag(const char* name, const char* value, const char** error) {
   Flag* flag = Lookup(name);
   if (flag == NULL) {