1 files changed, 57 insertions, 0 deletions
diff --git a/libgo/runtime/go-callers.c b/libgo/runtime/go-callers.c
new file mode 100644
index 00000000000..65babbe1221
--- /dev/null
+++ b/libgo/runtime/go-callers.c
@@ -0,0 +1,57 @@
+/* go-callers.c -- get callers for Go.
+
+   Copyright 2012 The Go Authors. All rights reserved.
+   Use of this source code is governed by a BSD-style
+   license that can be found in the LICENSE file.  */
+
+#include "config.h"
+
+#include "unwind.h"
+
+#include "runtime.h"
+
+/* Argument passed to backtrace function.  */
+
+struct callers_data
+{
+  int skip;
+  uintptr *pcbuf;
+  int index;
+  int max;
+};
+
+static _Unwind_Reason_Code
+backtrace (struct _Unwind_Context *context, void *varg)
+{
+  struct callers_data *arg = (struct callers_data *) varg;
+  uintptr pc;
+
+  pc = _Unwind_GetIP (context);
+
+  /* FIXME: If PC is in the __morestack routine, we should ignore
+     it.  */
+
+  if (arg->skip > 0)
+    --arg->skip;
+  else if (arg->index >= arg->max)
+    return _URC_END_OF_STACK;
+  else
+    {
+      arg->pcbuf[arg->index] = pc;
+      ++arg->index;
+    }
+  return _URC_NO_REASON;
+}
+
+int32
+runtime_callers (int32 skip, uintptr *pcbuf, int32 m)
+{
+  struct callers_data arg;
+
+  arg.skip = skip;
+  arg.pcbuf = pcbuf;
+  arg.index = 0;
+  arg.max = m;
+  _Unwind_Backtrace (backtrace, &arg);
+  return arg.index;
+}