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gdb: pass frames as const frame_info_ptr &

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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 <aburgess@redhat.com>
This commit is contained in:
Simon Marchi
2024-02-19 13:07:47 -05:00
parent 1b2c120daf
commit 8480a37e14
224 changed files with 1351 additions and 1339 deletions
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8
gdb/ft32-tdep.c
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@@ -450,7 +450,7 @@ ft32_alloc_frame_cache (void)
/* Populate a ft32_frame_cache object for this_frame. */
static struct ft32_frame_cache *
ft32_frame_cache (frame_info_ptr this_frame, void **this_cache)
ft32_frame_cache (const frame_info_ptr &this_frame, void **this_cache)
{
struct ft32_frame_cache *cache;
CORE_ADDR current_pc;
@@ -490,7 +490,7 @@ ft32_frame_cache (frame_info_ptr this_frame, void **this_cache)
frame. This will be used to create a new GDB frame struct. */
static void
ft32_frame_this_id (frame_info_ptr this_frame,
ft32_frame_this_id (const frame_info_ptr &this_frame,
void **this_prologue_cache, struct frame_id *this_id)
{
struct ft32_frame_cache *cache = ft32_frame_cache (this_frame,
@@ -506,7 +506,7 @@ ft32_frame_this_id (frame_info_ptr this_frame,
/* Get the value of register regnum in the previous stack frame. */
static struct value *
ft32_frame_prev_register (frame_info_ptr this_frame,
ft32_frame_prev_register (const frame_info_ptr &this_frame,
void **this_prologue_cache, int regnum)
{
struct ft32_frame_cache *cache = ft32_frame_cache (this_frame,
@@ -538,7 +538,7 @@ static const struct frame_unwind ft32_frame_unwind =
/* Return the base address of this_frame. */
static CORE_ADDR
ft32_frame_base_address (frame_info_ptr this_frame, void **this_cache)
ft32_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)
{
struct ft32_frame_cache *cache = ft32_frame_cache (this_frame,
this_cache);