On Tue, Jun 14, 2022 at 09:01:54PM +0530, Siddhesh Poyarekar wrote:
> The addr_expr computation does not check for error_mark_node before
> returning the size expression. This used to work in the constant case
> because the conversion to uhwi would end up causing it to return
> size_unknown, but that won't work for the dynamic case.
Regarding subject/first line of commit, it should be something like:
tree-object-size: Don't let error_mark_node escape for ADDR_EXPR [PR105736]
instead of what you have.
> Modify the control flow to explicitly return size_unknown if the offset
> computation returns an error_mark_node.
>
> gcc/ChangeLog:
>
> PR tree-optimization/105736
> * tree-object-size.cc (addr_object_size): Return size_unknown
> when object offset computation returns an error.
>
> gcc/testsuite/ChangeLog:
>
> PR tree-optimization/105736
> * gcc.dg/builtin-dynamic-object-size-0.c (TV4, val3,
> test_pr105736): New struct declaration, variable and function to
> test PR.
If you want to spell the exact changes in the test, it would be better
to do it separately when it is different changes.
* gcc.dg/builtin-dynamic-object-size-0.c (struct TV4): New type.
(val3): New variable.
(test_pr105736): New function.
> (main): Use them.
Otherwise LGTM, but for GCC 13, it would be nice to add support
for BIT_FIELD_REF if both second and third arguments are multiples of
BITS_PER_UNIT.
Something like:
case BIT_FIELD_REF:
if (!tree_fits_shwi_p (TREE_OPERAND (expr, 1))
|| !tree_fits_shwi_p (TREE_OPERAND (expr, 2))
|| (tree_to_shwi (TREE_OPERAND (expr, 1)) % BITS_PER_UNIT)
|| (tree_to_shwi (TREE_OPERAND (expr, 2)) % BITS_PER_UNIT))
return error_mark_node;
base = compute_object_offset (TREE_OPERAND (expr, 0), var);
if (base == error_mark_node)
return base;
off = size_int (tree_to_shwi (TREE_OPERAND (expr, 2)
/ BITS_PER_UNIT));
break;
or so.
>
> Signed-off-by: Siddhesh Poyarekar <siddh...@gotplt.org>
> ---
> Changes from v1:
> - Used FAIL() instead of __builtin_abort() in the test.
>
> Tested:
>
> - x86_64 bootstrap and test
> - --with-build-config=bootstrap-ubsan build
>
> May I also backport this to gcc12?
Ok.
Jakub
