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, 31 insertions, 0 deletions

diff --git a/testsuite/systemtap.context/fib.c b/testsuite/systemtap.context/fib.c
new file mode 100644
index 00000000..61fee0a7
--- /dev/null
+++ b/testsuite/systemtap.context/fib.c
@@ -0,0 +1,31 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+long fib(int x)
+{
+  if (x == 0 || x == 1)
+    return 1;
+  else
+    return fib(x - 1) + fib(x - 2);
+}
+
+int main(int argc, char **argv)
+{
+  int x = 0;
+  long result = 0;
+
+  if (argc != 2)
+    {
+      printf("0\n");
+      return 1;
+    }
+  x = atoi(argv[1]);
+  if (x < 0)
+    {
+      printf("0\n");
+      return 1;
+    }
+  result = fib(x);
+  printf("%ld\n", result);
+  return 0;
+}