On 2025-06-19 12:07, Siddhesh Poyarekar wrote:
On 2025-06-16 18:08, Qing Zhao wrote:
gcc/ChangeLog:
* tree-object-size.cc (access_with_size_object_size): Handle pointers
with counted_by.
This should probably just say "Update comment for .ACCESS_WITH_SIZE.".
(collect_object_sizes_for): Likewise.
Oh, and this should be updated accordingly as well.
@@ -1854,6 +1856,10 @@ collect_object_sizes_for (struct
object_size_info *osi, tree var)
if (TREE_CODE (rhs) == SSA_NAME
&& POINTER_TYPE_P (TREE_TYPE (rhs)))
reexamine = merge_object_sizes (osi, var, rhs);
+ else if (TREE_CODE (rhs) == MEM_REF
+ && POINTER_TYPE_P (TREE_TYPE (rhs))
+ && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
+ reexamine = merge_object_sizes (osi, var, TREE_OPERAND
(rhs, 0));
else
expr_object_size (osi, var, rhs);
}
Interesting, looks like this would improve coverage for more than just
this specific case of pointers within structs. Nice! Is this what
pointer-counted-by-7.c covers?
Actually, I wonder if this is incomplete. We should be able to get the
object size even if TREE_OPERAND (rhs, 0) is not an SSA_NAME, like we do
in addr_object_size:
```
if (TREE_CODE (pt_var) == MEM_REF)
{
tree sz, wholesize;
if (!osi || (object_size_type & OST_SUBOBJECT) != 0
|| TREE_CODE (TREE_OPERAND (pt_var, 0)) != SSA_NAME)
{
compute_builtin_object_size (TREE_OPERAND (pt_var, 0),
object_size_type &
~OST_SUBOBJECT, &sz);
wholesize = sz;
}
else
{
tree var = TREE_OPERAND (pt_var, 0);
if (osi->pass == 0)
collect_object_sizes_for (osi, var);
if (bitmap_bit_p (computed[object_size_type],
SSA_NAME_VERSION (var)))
{
sz = object_sizes_get (osi, SSA_NAME_VERSION (var));
wholesize = object_sizes_get (osi, SSA_NAME_VERSION
(var), true);
}
else
sz = wholesize = size_unknown (object_size_type);
}
if (!size_unknown_p (sz, object_size_type))
sz = size_for_offset (sz, TREE_OPERAND (pt_var, 1), wholesize);
if (!size_unknown_p (sz, object_size_type)
&& (TREE_CODE (sz) != INTEGER_CST
|| compare_tree_int (sz, offset_limit) < 0))
{
pt_var_size = sz;
pt_var_wholesize = wholesize;
}
}
```
Maybe refactor this to handle MEM_REF and update addr_object_size (and
collect_object_sizes_for for the gimple_assign_single_p case) to use it?
However, that's a more general change and we'd probably need a new test
case to validate it. I won't block on this though, your minimal change
is a step forward, maybe just add a comment about this?
Thanks,
Sid
