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

3 files changed, 85 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;
+}
diff --git a/testsuite/systemtap.context/fib.exp b/testsuite/systemtap.context/fib.exp
new file mode 100644
index 00000000..cc4d75a1
--- /dev/null
+++ b/testsuite/systemtap.context/fib.exp
@@ -0,0 +1,37 @@
+# Tests backtrace in the classic Fibonacci program
+
+
+set test "fib"
+
+# Only run on make installcheck and utrace present.
+if {! [installtest_p]} { untested "$test"; return }
+if {! [utrace_p]} { untested "$test"; return }
+
+set testpath  "$srcdir/$subdir"
+set testsrc   "$testpath/fib.c"
+set testexe   "[pwd]/$test"
+
+# We want debug info and no optimization (is that totally necessary?)
+set testflags "additional_flags=-g additional_flags=-O0"
+set teststp   "$testpath/$test.stp"
+
+set res [target_compile $testsrc $testexe executable $testflags]
+if { $res != "" } {
+    verbose "target_compile failed: $res" 2
+    fail "unable to compile $testsrc"
+    return
+}
+
+spawn stap -c "$testexe 10" $teststp
+set fibcalls 0
+set maincalls 0
+expect {
+    -timeout 120
+    -re {^fib[^\r\n]*[\r\n]} { incr fibcalls; exp_continue }
+    -re {^main[^\r\n]*[\r\n]} { incr maincalls; exp_continue }
+    -re {^[^\r\n]*[\r\n]} {exp_continue}
+    timeout { fail "$test (timeout)" }
+    eof { }
+}
+wait
+if {$fibcalls == 18 && $maincalls == 2} { pass "$test ($fibcalls $maincalls)" } { fail "$test ($fibcalls $maincalls)" }
diff --git a/testsuite/systemtap.context/fib.stp b/testsuite/systemtap.context/fib.stp
new file mode 100644
index 00000000..85c2fc1d
--- /dev/null
+++ b/testsuite/systemtap.context/fib.stp
@@ -0,0 +1,17 @@
+global depth = 0
+global max_depth = 0
+
+probe process("fib").function("fib").call {
+    depth++
+    if (depth > max_depth) {
+            max_depth = depth
+    }
+}
+
+probe process("fib").function("fib").return {
+    if (depth == max_depth) {
+            print_ubacktrace_brief()
+            printf("\n")
+    }
+    depth--
+}