On Wed, Dec 28, 2022 at 1:47 PM Alexandre Oliva via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Dec 28, 2022, Martin Liška <mli...@suse.cz> wrote:
>
> > I really like the verification code you added. It's quite similar to what
> > I added to hash-table.h:
>
> *nod*
>
> Prompted by your encouragement, I've combined the element count
> verification code with the verify() loop, and also added it to expand,
> where it can be done cheaply.
>
>
> Add cheap verification of element and deleted entry counts during
> expand and hash verify.
>
> Regstrapped on x86_64-linux-gnu. Ok to install?
OK.
>
> for gcc/ChangeLog
>
> * hash-table.h (expand): Check elements and deleted counts.
> (verify): Likewise.
> ---
> gcc/hash-table.h | 35 ++++++++++++++++++++++++++++-------
> 1 file changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/gcc/hash-table.h b/gcc/hash-table.h
> index 53507daae26c3..f4bda6102323e 100644
> --- a/gcc/hash-table.h
> +++ b/gcc/hash-table.h
> @@ -805,19 +805,28 @@ hash_table<Descriptor, Lazy, Allocator>::expand ()
> hash_table_usage ().release_instance_overhead (this, sizeof (value_type)
> * osize);
>
> + size_t n_deleted = m_n_deleted;
> +
> m_entries = nentries;
> m_size = nsize;
> m_size_prime_index = nindex;
> m_n_elements -= m_n_deleted;
> m_n_deleted = 0;
>
> + size_t n_elements = m_n_elements;
> +
> value_type *p = oentries;
> do
> {
> value_type &x = *p;
>
> - if (!is_empty (x) && !is_deleted (x))
> + if (is_empty (x))
> + ;
> + else if (is_deleted (x))
> + n_deleted--;
> + else
> {
> + n_elements--;
> value_type *q = find_empty_slot_for_expand (Descriptor::hash (x));
> new ((void*) q) value_type (std::move (x));
> /* After the resources of 'x' have been moved to a new object at
> 'q',
> @@ -829,6 +838,8 @@ hash_table<Descriptor, Lazy, Allocator>::expand ()
> }
> while (p < olimit);
>
> + gcc_checking_assert (!n_elements && !n_deleted);
> +
> if (!m_ggc)
> Allocator <value_type> ::data_free (oentries);
> else
> @@ -1018,8 +1029,9 @@ hash_table<Descriptor, Lazy, Allocator>
> return &m_entries[index];
> }
>
> -/* Verify that all existing elements in th hash table which are
> - equal to COMPARABLE have an equal HASH value provided as argument. */
> +/* Verify that all existing elements in the hash table which are
> + equal to COMPARABLE have an equal HASH value provided as argument.
> + Also check that the hash table element counts are correct. */
>
> template<typename Descriptor, bool Lazy,
> template<typename Type> class Allocator>
> @@ -1027,14 +1039,23 @@ void
> hash_table<Descriptor, Lazy, Allocator>
> ::verify (const compare_type &comparable, hashval_t hash)
> {
> + size_t n_elements = m_n_elements;
> + size_t n_deleted = m_n_deleted;
> for (size_t i = 0; i < MIN (hash_table_sanitize_eq_limit, m_size); i++)
> {
> value_type *entry = &m_entries[i];
> - if (!is_empty (*entry) && !is_deleted (*entry)
> - && hash != Descriptor::hash (*entry)
> - && Descriptor::equal (*entry, comparable))
> - hashtab_chk_error ();
> + if (!is_empty (*entry))
> + {
> + n_elements--;
> + if (is_deleted (*entry))
> + n_deleted--;
> + else if (hash != Descriptor::hash (*entry)
> + && Descriptor::equal (*entry, comparable))
> + hashtab_chk_error ();
> + }
> }
> + if (hash_table_sanitize_eq_limit >= m_size)
> + gcc_checking_assert (!n_elements && !n_deleted);
> }
>
> /* This function deletes an element with the given COMPARABLE value
>
>
> --
> Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
> Free Software Activist GNU Toolchain Engineer
> Disinformation flourishes because many people care deeply about injustice
> but very few check the facts. Ask me about <https://stallmansupport.org>
