backtrace through uprobes trampoline.

Only works in uretprobes for the moment.

* runtime/stack-x86_64.c (__stp_stack_print): Rewrite trampoline PC
  addresses if necessary.
* runtime/stack-i386.c (__stp_stack_print): ditto
* runtime/stack-arm.c (__stp_stack_print): Add extra argument
* runtime/stack-ppc.c (__stp_stack_print): ditto
* runtime/stack-s390.c (__stp_stack_print): ditto
* runtime/stack.c (_stap_stack_print): call __stp_stack_print with
  uretprobe_instance.
* testsuite/systemtap.context/uprobe_backtrace.stp: new test

1 files changed, 31 insertions, 0 deletions

diff --git a/testsuite/systemtap.context/uprobe_backtrace.stp b/testsuite/systemtap.context/uprobe_backtrace.stp
new file mode 100644
index 00000000..6d6fe3f7
--- /dev/null
+++ b/testsuite/systemtap.context/uprobe_backtrace.stp
@@ -0,0 +1,31 @@
+probe process("uprobe_uaddr").function("main").call {
+    print_ubacktrace()
+    printf("\n")
+}
+
+probe process("uprobe_uaddr").function("main").return {
+    print_ubacktrace()
+    printf("\n")
+}
+
+probe process("uprobe_uaddr").function("func").call {
+    print_ubacktrace()
+    printf("\n")
+}
+
+probe process("uprobe_uaddr").function("func").return {
+    print_ubacktrace()
+    printf("\n")
+}
+
+
+probe process("uprobe_uaddr").function("func2").call {
+    print_ubacktrace()
+    printf("\n")
+}
+
+
+probe process("uprobe_uaddr").function("func2").return {
+    print_ubacktrace()
+    printf("\n")
+}