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/csky-tdep.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'gdb/csky-tdep.c') diff --git a/gdb/csky-tdep.c b/gdb/csky-tdep.c index 2aa6c0a..c1ce8a5 100644 --- a/gdb/csky-tdep.c +++ b/gdb/csky-tdep.c @@ -958,7 +958,7 @@ csky_analyze_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc, CORE_ADDR limit_pc, CORE_ADDR end_pc, - frame_info_ptr this_frame, + const frame_info_ptr &this_frame, struct csky_unwind_cache *this_cache, lr_type_t lr_type) { @@ -2063,7 +2063,7 @@ csky_analyze_lr_type (struct gdbarch *gdbarch, /* Heuristic unwinder. */ static struct csky_unwind_cache * -csky_frame_unwind_cache (frame_info_ptr this_frame) +csky_frame_unwind_cache (const frame_info_ptr &this_frame) { CORE_ADDR prologue_start, prologue_end, func_end, prev_pc, block_addr; struct csky_unwind_cache *cache; @@ -2122,7 +2122,7 @@ csky_frame_unwind_cache (frame_info_ptr this_frame) /* Implement the this_id function for the normal unwinder. */ static void -csky_frame_this_id (frame_info_ptr this_frame, +csky_frame_this_id (const frame_info_ptr &this_frame, void **this_prologue_cache, struct frame_id *this_id) { struct csky_unwind_cache *cache; @@ -2143,7 +2143,7 @@ csky_frame_this_id (frame_info_ptr this_frame, /* Implement the prev_register function for the normal unwinder. */ static struct value * -csky_frame_prev_register (frame_info_ptr this_frame, +csky_frame_prev_register (const frame_info_ptr &this_frame, void **this_prologue_cache, int regnum) { struct csky_unwind_cache *cache; @@ -2172,7 +2172,7 @@ static const struct frame_unwind csky_unwind_cache = { }; static CORE_ADDR -csky_check_long_branch (frame_info_ptr frame, CORE_ADDR pc) +csky_check_long_branch (const frame_info_ptr &frame, CORE_ADDR pc) { gdb_byte buf[8]; struct gdbarch *gdbarch = get_frame_arch (frame); @@ -2209,7 +2209,7 @@ csky_check_long_branch (frame_info_ptr frame, CORE_ADDR pc) static int csky_stub_unwind_sniffer (const struct frame_unwind *self, - frame_info_ptr this_frame, + const frame_info_ptr &this_frame, void **this_prologue_cache) { CORE_ADDR addr_in_block, pc; @@ -2240,7 +2240,7 @@ csky_stub_unwind_sniffer (const struct frame_unwind *self, } static struct csky_unwind_cache * -csky_make_stub_cache (frame_info_ptr this_frame) +csky_make_stub_cache (const frame_info_ptr &this_frame) { struct csky_unwind_cache *cache; @@ -2252,7 +2252,7 @@ csky_make_stub_cache (frame_info_ptr this_frame) } static void -csky_stub_this_id (frame_info_ptr this_frame, +csky_stub_this_id (const frame_info_ptr &this_frame, void **this_cache, struct frame_id *this_id) { @@ -2267,7 +2267,7 @@ csky_stub_this_id (frame_info_ptr this_frame, } static struct value * -csky_stub_prev_register (frame_info_ptr this_frame, +csky_stub_prev_register (const frame_info_ptr &this_frame, void **this_cache, int prev_regnum) { @@ -2307,7 +2307,7 @@ static frame_unwind csky_stub_unwind = { for the normal unwinder. */ static CORE_ADDR -csky_frame_base_address (frame_info_ptr this_frame, void **this_cache) +csky_frame_base_address (const frame_info_ptr &this_frame, void **this_cache) { struct csky_unwind_cache *cache; @@ -2330,7 +2330,7 @@ static const struct frame_base csky_frame_base = { static void csky_dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum, struct dwarf2_frame_state_reg *reg, - frame_info_ptr this_frame) + const frame_info_ptr &this_frame) { if (regnum == gdbarch_pc_regnum (gdbarch)) reg->how = DWARF2_FRAME_REG_RA; -- cgit v1.1