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/ppc64-tdep.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) (limited to 'gdb/ppc64-tdep.c') diff --git a/gdb/ppc64-tdep.c b/gdb/ppc64-tdep.c index d415836..5797d55 100644 --- a/gdb/ppc64-tdep.c +++ b/gdb/ppc64-tdep.c @@ -85,7 +85,7 @@ Return the function's entry point. */ static CORE_ADDR -ppc64_plt_entry_point (frame_info_ptr frame, CORE_ADDR plt_off) +ppc64_plt_entry_point (const frame_info_ptr &frame, CORE_ADDR plt_off) { struct gdbarch *gdbarch = get_frame_arch (frame); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); @@ -108,7 +108,7 @@ ppc64_plt_entry_point (frame_info_ptr frame, CORE_ADDR plt_off) } static CORE_ADDR -ppc64_plt_pcrel_entry_point (frame_info_ptr frame, CORE_ADDR plt_off, +ppc64_plt_pcrel_entry_point (const frame_info_ptr &frame, CORE_ADDR plt_off, CORE_ADDR pc) { struct gdbarch *gdbarch = get_frame_arch (frame); @@ -546,7 +546,7 @@ static const struct ppc_insn_pattern ppc64_standard_linkage12[] = dynamic linker lazy symbol resolution stubs.) */ static CORE_ADDR -ppc64_standard_linkage1_target (frame_info_ptr frame, unsigned int *insn) +ppc64_standard_linkage1_target (const frame_info_ptr &frame, unsigned int *insn) { CORE_ADDR plt_off = ((ppc_insn_d_field (insn[0]) << 16) + ppc_insn_ds_field (insn[2])); @@ -555,7 +555,7 @@ ppc64_standard_linkage1_target (frame_info_ptr frame, unsigned int *insn) } static CORE_ADDR -ppc64_standard_linkage2_target (frame_info_ptr frame, unsigned int *insn) +ppc64_standard_linkage2_target (const frame_info_ptr &frame, unsigned int *insn) { CORE_ADDR plt_off = ((ppc_insn_d_field (insn[1]) << 16) + ppc_insn_ds_field (insn[3])); @@ -564,7 +564,7 @@ ppc64_standard_linkage2_target (frame_info_ptr frame, unsigned int *insn) } static CORE_ADDR -ppc64_standard_linkage3_target (frame_info_ptr frame, unsigned int *insn) +ppc64_standard_linkage3_target (const frame_info_ptr &frame, unsigned int *insn) { CORE_ADDR plt_off = ppc_insn_ds_field (insn[1]); @@ -572,7 +572,7 @@ ppc64_standard_linkage3_target (frame_info_ptr frame, unsigned int *insn) } static CORE_ADDR -ppc64_standard_linkage4_target (frame_info_ptr frame, unsigned int *insn) +ppc64_standard_linkage4_target (const frame_info_ptr &frame, unsigned int *insn) { CORE_ADDR plt_off = ((ppc_insn_d_field (insn[1]) << 16) + ppc_insn_ds_field (insn[2])); @@ -581,7 +581,7 @@ ppc64_standard_linkage4_target (frame_info_ptr frame, unsigned int *insn) } static CORE_ADDR -ppc64_pcrel_linkage1_target (frame_info_ptr frame, unsigned int *insn, +ppc64_pcrel_linkage1_target (const frame_info_ptr &frame, unsigned int *insn, CORE_ADDR pc) { /* insn[0] is for the std instruction. */ @@ -591,7 +591,7 @@ ppc64_pcrel_linkage1_target (frame_info_ptr frame, unsigned int *insn, } static CORE_ADDR -ppc64_pcrel_linkage2_target (frame_info_ptr frame, unsigned int *insn, +ppc64_pcrel_linkage2_target (const frame_info_ptr &frame, unsigned int *insn, CORE_ADDR pc) { CORE_ADDR plt_off; @@ -611,7 +611,7 @@ ppc64_pcrel_linkage2_target (frame_info_ptr frame, unsigned int *insn, check whether we are in the middle of a PLT stub. */ static CORE_ADDR -ppc64_skip_trampoline_code_1 (frame_info_ptr frame, CORE_ADDR pc) +ppc64_skip_trampoline_code_1 (const frame_info_ptr &frame, CORE_ADDR pc) { #define MAX(a,b) ((a) > (b) ? (a) : (b)) unsigned int insns[MAX (MAX (MAX (ARRAY_SIZE (ppc64_standard_linkage1), @@ -707,7 +707,7 @@ ppc64_skip_trampoline_code_1 (frame_info_ptr frame, CORE_ADDR pc) ppc_elfv2_skip_entrypoint. */ CORE_ADDR -ppc64_skip_trampoline_code (frame_info_ptr frame, CORE_ADDR pc) +ppc64_skip_trampoline_code (const frame_info_ptr &frame, CORE_ADDR pc) { struct gdbarch *gdbarch = get_frame_arch (frame); -- cgit v1.1