From 8480a37e146c40e82a93c0ecf6144571516c95c5 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Mon, 19 Feb 2024 13:07:47 -0500 Subject: gdb: pass frames as `const frame_info_ptr &` We currently pass frames to function by value, as `frame_info_ptr`. This is somewhat expensive: - the size of `frame_info_ptr` is 64 bytes, which is a bit big to pass by value - the constructors and destructor link/unlink the object in the global `frame_info_ptr::frame_list` list. This is an `intrusive_list`, so it's not so bad: it's just assigning a few points, there's no memory allocation as if it was `std::list`, but still it's useless to do that over and over. As suggested by Tom Tromey, change many function signatures to accept `const frame_info_ptr &` instead of `frame_info_ptr`. Some functions reassign their `frame_info_ptr` parameter, like: void the_func (frame_info_ptr frame) { for (; frame != nullptr; frame = get_prev_frame (frame)) { ... } } I wondered what to do about them, do I leave them as-is or change them (and need to introduce a separate local variable that can be re-assigned). I opted for the later for consistency. It might not be clear why some functions take `const frame_info_ptr &` while others take `frame_info_ptr`. Also, if a function took a `frame_info_ptr` because it did re-assign its parameter, I doubt that we would think to change it to `const frame_info_ptr &` should the implementation change such that it doesn't need to take `frame_info_ptr` anymore. It seems better to have a simple rule and apply it everywhere. Change-Id: I59d10addef687d157f82ccf4d54f5dde9a963fd0 Approved-By: Andrew Burgess --- gdb/i386-obsd-tdep.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'gdb/i386-obsd-tdep.c') diff --git a/gdb/i386-obsd-tdep.c b/gdb/i386-obsd-tdep.c index 38ba280..e1480ec 100644 --- a/gdb/i386-obsd-tdep.c +++ b/gdb/i386-obsd-tdep.c @@ -64,7 +64,7 @@ static const int i386obsd_sigreturn_offset[] = { routine. */ static int -i386obsd_sigtramp_p (frame_info_ptr this_frame) +i386obsd_sigtramp_p (const frame_info_ptr &this_frame) { CORE_ADDR pc = get_frame_pc (this_frame); CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1)); @@ -303,7 +303,7 @@ static int i386obsd_tf_reg_offset[] = }; static struct trad_frame_cache * -i386obsd_trapframe_cache (frame_info_ptr this_frame, void **this_cache) +i386obsd_trapframe_cache (const frame_info_ptr &this_frame, void **this_cache) { struct gdbarch *gdbarch = get_frame_arch (this_frame); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); @@ -350,7 +350,7 @@ i386obsd_trapframe_cache (frame_info_ptr this_frame, void **this_cache) } static void -i386obsd_trapframe_this_id (frame_info_ptr this_frame, +i386obsd_trapframe_this_id (const frame_info_ptr &this_frame, void **this_cache, struct frame_id *this_id) { struct trad_frame_cache *cache = @@ -360,7 +360,7 @@ i386obsd_trapframe_this_id (frame_info_ptr this_frame, } static struct value * -i386obsd_trapframe_prev_register (frame_info_ptr this_frame, +i386obsd_trapframe_prev_register (const frame_info_ptr &this_frame, void **this_cache, int regnum) { struct trad_frame_cache *cache = @@ -371,7 +371,7 @@ i386obsd_trapframe_prev_register (frame_info_ptr this_frame, static int i386obsd_trapframe_sniffer (const struct frame_unwind *self, - frame_info_ptr this_frame, + const frame_info_ptr &this_frame, void **this_prologue_cache) { ULONGEST cs; -- cgit v1.1