From a154d838a70e96d888620c072e2d6ea8bdf044ca Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Tue, 29 Jun 2021 12:05:03 -0400 Subject: gdb: add names to unwinders, add debug messages when looking for unwinder I wrote this while debugging a problem where the expected unwinder for a frame wasn't used. It adds messages to show which unwinders are considered for a frame, why they are not selected (if an exception is thrown), and finally which unwinder is selected in the end. To be able to show a meaningful, human-readable name for the unwinders, add a "name" field to struct frame_unwind, and update all instances to include a name. Here's an example of the output: [frame] frame_unwind_find_by_frame: this_frame=0 [frame] frame_unwind_try_unwinder: trying unwinder "dummy" [frame] frame_unwind_try_unwinder: no [frame] frame_unwind_try_unwinder: trying unwinder "dwarf2 tailcall" [frame] frame_unwind_try_unwinder: no [frame] frame_unwind_try_unwinder: trying unwinder "inline" [frame] frame_unwind_try_unwinder: no [frame] frame_unwind_try_unwinder: trying unwinder "jit" [frame] frame_unwind_try_unwinder: no [frame] frame_unwind_try_unwinder: trying unwinder "python" [frame] frame_unwind_try_unwinder: no [frame] frame_unwind_try_unwinder: trying unwinder "amd64 epilogue" [frame] frame_unwind_try_unwinder: no [frame] frame_unwind_try_unwinder: trying unwinder "i386 epilogue" [frame] frame_unwind_try_unwinder: no [frame] frame_unwind_try_unwinder: trying unwinder "dwarf2" [frame] frame_unwind_try_unwinder: yes gdb/ChangeLog: * frame-unwind.h (struct frame_unwind) : New. Update instances everywhere to include this field. * frame-unwind.c (frame_unwind_try_unwinder, frame_unwind_find_by_frame): Add debug messages. Change-Id: I813f17777422425f0d08b22499817b23922e8ddb --- gdb/frame-unwind.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'gdb/frame-unwind.c') diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c index b19e95d..0fef2c1 100644 --- a/gdb/frame-unwind.c +++ b/gdb/frame-unwind.c @@ -127,10 +127,13 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache, try { + frame_debug_printf ("trying unwinder \"%s\"", unwinder->name); res = unwinder->sniffer (unwinder, this_frame, this_cache); } catch (const gdb_exception &ex) { + frame_debug_printf ("caught exception: %s", ex.message->c_str ()); + /* Catch all exceptions, caused by either interrupt or error. Reset *THIS_CACHE, unless something reinitialized the frame cache meanwhile, in which case THIS_FRAME/THIS_CACHE are now @@ -153,9 +156,13 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache, } if (res) - return 1; + { + frame_debug_printf ("yes"); + return 1; + } else { + frame_debug_printf ("no"); /* Don't set *THIS_CACHE to NULL here, because sniffer has to do so. */ frame_cleanup_after_sniffer (this_frame); @@ -171,6 +178,8 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache, void frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache) { + frame_debug_printf ("this_frame=%d", frame_relative_level (this_frame)); + struct gdbarch *gdbarch = get_frame_arch (this_frame); struct frame_unwind_table *table = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data); -- cgit v1.1