Add gdb helper functions for creating a handle and using ToCString with RawObjects.

runtime/vm/gdb_helpers.cc

Index: runtime/vm/gdb_helpers.cc
diff --git a/runtime/vm/gdb_helpers.cc b/runtime/vm/gdb_helpers.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2a9ab6bb7480d5a9786dbf0df786aadec22f358a
--- /dev/null
+++ b/runtime/vm/gdb_helpers.cc
@@ -0,0 +1,76 @@
+// Copyright (c) 2017, 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/object.h"
+#include "vm/stack_frame.h"
+
+#include "lib/stacktrace.h"
+
+namespace dart {
+
+DART_NOINLINE
+void _printRawObject(RawObject* object) {
+  OS::PrintErr("%s\n", Object::Handle(object).ToCString());
+}
+
+
+DART_NOINLINE
+Object& _handle(RawObject* object) {
+  return Object::Handle(object);
+}
+
+
+// An utility method for convenient printing of dart stack traces when
+// inside 'gdb'. Note: This function will only work when there is a
+// valid exit frame information. It will not work when a breakpoint is
+// set in dart code and control is got inside 'gdb' without going through
+// the runtime or native transition stub.
+DART_NOINLINE
+void _printDartStackTrace() {
+  const StackTrace& stacktrace = GetCurrentStackTrace(0);
+  OS::PrintErr("=== Current Trace:\n%s===\n", stacktrace.ToCString());
+}
+
+
+DART_NOINLINE

[siva, 2017/06/26 20:19:05]

Seems to have lost the comment
// Like _printCurrentStackTrace, but works in a NoSafepointScope.

maybe add a comment describing when this method should be used.

[rmacnak, 2017/06/28 00:03:00]

Done.

+void _printStackTrace() {
+  StackFrameIterator frames(StackFrameIterator::kDontValidateFrames,
+                            Thread::Current(),
+                            StackFrameIterator::kNoCrossThreadIteration);
+  StackFrame* frame = frames.NextFrame();
+  while (frame != NULL) {
+    OS::PrintErr("%s\n", frame->ToCString());
+    frame = frames.NextFrame();
+  }
+}
+
+
+class PrintObjectPointersVisitor : public ObjectPointerVisitor {
+ public:
+  PrintObjectPointersVisitor() : ObjectPointerVisitor(Isolate::Current()) {}
+
+  void VisitPointers(RawObject** first, RawObject** last) {
+    for (RawObject** p = first; p <= last; p++) {
+      Object& obj = Object::Handle(*p);
+      OS::PrintErr("%p: %s\n", p, obj.ToCString());
+    }
+  }
+};
+
+
+DART_NOINLINE
+void _printStackTraceWithLocals() {
+  PrintObjectPointersVisitor visitor;
+  StackFrameIterator frames(StackFrameIterator::kDontValidateFrames,
+                            Thread::Current(),
+                            StackFrameIterator::kNoCrossThreadIteration);
+  StackFrame* frame = frames.NextFrame();
+  while (frame != NULL) {
+    OS::PrintErr("%s\n", frame->ToCString());
+    frame->VisitObjectPointers(&visitor);
+    frame = frames.NextFrame();
+  }
+}
+

[siva, 2017/06/26 20:19:05]

Should this entire file be wrapped under #if !defined(PRODUCT) ... #endif

[zra, 2017/06/26 20:31:23]

+1

[rmacnak, 2017/06/28 00:03:00]

Done.

+}  // namespace dart