support for a brief backtrace format

This only prints symbol+offset, or an address if the symbol isn't
known.

* runtime/runtime.h (SYM_VERBOSE_NO, SYM_VERBOSE_FULL,
  SYM_VERBOSE_BRIEF): new constants
* runtime/stack.c (_stp_stack_print): support brief format
* runtime/sym.c (_stp_func_print): ditto
* tapset/ucontext-unwind.stp (print_ubacktrace_brief): new function
* testsuite/systemtap.context/fib.c: new test program
* testsuite/systemtap.context/fib.stp: new test
* testsuite/systemtap.context/fib.exp: new test

1 files changed, 18 insertions, 0 deletions

diff --git a/tapset/ucontext-unwind.stp b/tapset/ucontext-unwind.stp
index e0d883b8..399ce0c5 100644
--- a/tapset/ucontext-unwind.stp
+++ b/tapset/ucontext-unwind.stp
@@ -35,6 +35,24 @@ function print_ubacktrace () %{ /* unprivileged */
 %}
 
 /**
+ * sfunction print_ubacktrace_brief- Print stack back trace for current task. EXPERIMENTAL!
+ *
+ *  Equivalent to print_ubacktrace(), but output for each symbol is
+ *  shorter (just name and offset), and the function address is
+ *  printed if it can't be mapped to a name.
+ */
+
+function print_ubacktrace_brief () %{ /* unprivileged */
+        assert_is_myproc();
+	if (CONTEXT->regs) {
+		_stp_stack_print(CONTEXT->regs, SYM_VERBOSE_BRIEF, CONTEXT->pi,
+				 MAXTRACE, current, CONTEXT->ri);
+	} else {
+		_stp_printf("Systemtap probe: %s\n", CONTEXT->probe_point);
+	}
+%}
+
+/**
  * sfunction ubacktrace - Hex backtrace of current task stack. EXPERIMENTAL!
  *
  *  Return a string of hex addresses that are a backtrace of the