From 5add3fce49f1c36a47651238fb0b0592a04d645e Mon Sep 17 00:00:00 2001 From: Luis Machado Date: Thu, 2 Feb 2023 14:00:58 +0000 Subject: sme: Fixup sigframe gdbarch when vg/svg changes With SME, where you have two different vector lengths (vl and svl), it may be the case that the current frame has a set of vector lengths (A) but the signal context has a distinct set of vector lengths (B). In this case, we may run into a situation where GDB attempts to use a gdbarch created for set A, but it is really dealing with a frame that was using set B. This is problematic, specially with SME, because now we have a different number of pseudo-registers and types that gets cached on creation of each gdbarch variation. For AArch64 we really need to be able to use the correct gdbarch for each frame, and I noticed the signal frame (tramp-frame) doesn't have a settable prev_arch field. So it ends up using the default frame_unwind_arch function and eventually calling get_frame_arch (next_frame). That means the previous frame will always have the same gdbarch as the current frame. This patch first refactors the AArch64/Linux signal context code, simplifying it and making it reusable for our purposes of calculating the previous frame's gdbarch. I introduced a struct that holds information that we have found in the signal context, and with which we can make various decisions. Finally, a small change to tramp-frame.c and tramp-frame.h to expose a prev_arch hook that the architecture can set. With this new field, AArch64/Linux can implement a hook that looks at the signal context and infers the gdbarch for the previous frame. Regression-tested on aarch64-linux Ubuntu 22.04/20.04. Approved-By: Simon Marchi Reviewed-by: Thiago Jung Bauermann --- gdb/tramp-frame.c | 1 + 1 file changed, 1 insertion(+) (limited to 'gdb/tramp-frame.c') diff --git a/gdb/tramp-frame.c b/gdb/tramp-frame.c index c69ee6e..94e42e9 100644 --- a/gdb/tramp-frame.c +++ b/gdb/tramp-frame.c @@ -170,5 +170,6 @@ tramp_frame_prepend_unwinder (struct gdbarch *gdbarch, unwinder->stop_reason = default_frame_unwind_stop_reason; unwinder->this_id = tramp_frame_this_id; unwinder->prev_register = tramp_frame_prev_register; + unwinder->prev_arch = tramp_frame->prev_arch; frame_unwind_prepend_unwinder (gdbarch, unwinder); } -- cgit v1.1