btrace: check for indirect jump return in _Unwind_RaiseException
Commit Message
Some versions of _Unwind_RaiseException, e.g. on Fedora 28, use an
indirect jump to return to the exception handler.
This messes up the output of "record function-call-history /c" since the
return is interpreted as cross-function goto. It had been detected by
gdb.btrace/exception.exp.
Add a heuristic for "_Unwind_*" functions to interpret an indirect jump
that ends in one of our caller functions as return to the first instance
of that function in our call stack.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
gdb/
* btrace.c (ftrace_update_function): Add indirect jump heuristic.
---
gdb/btrace.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
@@ -620,6 +620,20 @@ ftrace_update_function (struct btrace_thread_info *btinfo, CORE_ADDR pc)
if (start == pc)
return ftrace_new_tailcall (btinfo, mfun, fun);
+ /* Some versions of _Unwind_RaiseException use an indirect
+ jump to 'return' to the exception handler of the caller
+ handling the exception instead of a return. Let's restrict
+ this heuristic to that and related functions. */
+ const char *fname = ftrace_print_function_name (bfun);
+ if (strncmp (fname, "_Unwind_", strlen ("_Unwind_")) == 0)
+ {
+ struct btrace_function *caller
+ = ftrace_find_call_by_number (btinfo, bfun->up);
+ caller = ftrace_find_caller (btinfo, caller, mfun, fun);
+ if (caller != NULL)
+ return ftrace_new_return (btinfo, mfun, fun);
+ }
+
/* If we can't determine the function for PC, we treat a jump at
the end of the block as tail call if we're switching functions
and as an intra-function branch if we don't. */