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/infrun.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) (limited to 'gdb/infrun.c') diff --git a/gdb/infrun.c b/gdb/infrun.c index fa68ab8..bbb98f6 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -88,9 +88,9 @@ static void follow_inferior_reset_breakpoints (void); static bool currently_stepping (struct thread_info *tp); -static void insert_hp_step_resume_breakpoint_at_frame (frame_info_ptr); +static void insert_hp_step_resume_breakpoint_at_frame (const frame_info_ptr &); -static void insert_step_resume_breakpoint_at_caller (frame_info_ptr); +static void insert_step_resume_breakpoint_at_caller (const frame_info_ptr &); static void insert_longjmp_resume_breakpoint (struct gdbarch *, CORE_ADDR); @@ -3838,7 +3838,7 @@ static void handle_step_into_function_backward (struct gdbarch *gdbarch, struct execution_control_state *ecs); static void handle_signal_stop (struct execution_control_state *ecs); static void check_exception_resume (struct execution_control_state *, - frame_info_ptr); + const frame_info_ptr &); static void end_stepping_range (struct execution_control_state *ecs); static void stop_waiting (struct execution_control_state *ecs); @@ -4771,7 +4771,7 @@ fetch_inferior_event () /* See infrun.h. */ void -set_step_info (thread_info *tp, frame_info_ptr frame, +set_step_info (thread_info *tp, const frame_info_ptr &frame, struct symtab_and_line sal) { /* This can be removed once this function no longer implicitly relies on the @@ -5003,8 +5003,10 @@ adjust_pc_after_break (struct thread_info *thread, } static bool -stepped_in_from (frame_info_ptr frame, struct frame_id step_frame_id) +stepped_in_from (const frame_info_ptr &initial_frame, frame_id step_frame_id) { + frame_info_ptr frame = initial_frame; + for (frame = get_prev_frame (frame); frame != nullptr; frame = get_prev_frame (frame)) @@ -8742,7 +8744,7 @@ insert_step_resume_breakpoint_at_sal (struct gdbarch *gdbarch, RETURN_FRAME.pc. */ static void -insert_hp_step_resume_breakpoint_at_frame (frame_info_ptr return_frame) +insert_hp_step_resume_breakpoint_at_frame (const frame_info_ptr &return_frame) { gdb_assert (return_frame != nullptr); @@ -8773,7 +8775,7 @@ insert_hp_step_resume_breakpoint_at_frame (frame_info_ptr return_frame) of frame_unwind_caller_id for an example). */ static void -insert_step_resume_breakpoint_at_caller (frame_info_ptr next_frame) +insert_step_resume_breakpoint_at_caller (const frame_info_ptr &next_frame) { /* We shouldn't have gotten here if we don't know where the call site is. */ @@ -8820,7 +8822,7 @@ insert_longjmp_resume_breakpoint (struct gdbarch *gdbarch, CORE_ADDR pc) static void insert_exception_resume_breakpoint (struct thread_info *tp, const struct block *b, - frame_info_ptr frame, + const frame_info_ptr &frame, struct symbol *sym) { try @@ -8863,7 +8865,7 @@ insert_exception_resume_breakpoint (struct thread_info *tp, static void insert_exception_resume_from_probe (struct thread_info *tp, const struct bound_probe *probe, - frame_info_ptr frame) + const frame_info_ptr &frame) { struct value *arg_value; CORE_ADDR handler; @@ -8892,7 +8894,7 @@ insert_exception_resume_from_probe (struct thread_info *tp, static void check_exception_resume (struct execution_control_state *ecs, - frame_info_ptr frame) + const frame_info_ptr &frame) { struct bound_probe probe; struct symbol *func; -- cgit v1.1