Hi!
On 2021-08-16T14:10:00-0600, Martin Sebor <mse...@gmail.com> wrote:
> On 8/16/21 6:44 AM, Thomas Schwinge wrote:
>> [...], to document the current behavior, I propose to
>> "Add more self-tests for 'hash_map' with Value type with non-trivial
>> constructor/destructor", see attached. OK to push to master branch?
>> (Also cherry-pick into release branches, eventually?)
(Attached again, for easy reference.)
> Adding more tests sounds like an excellent idea. I'm not sure about
> the idea of adding loopy selftests that iterate as many times as in
> the patch (looks like 1234 times two?)
Correct, and I agree it's a sensible concern, generally.
The current 1234 times two iterations is really arbitrary (should
document that in the test case), just so that we trigger a few hash table
expansions.
For 'selftest-c', we've got originally:
-fself-test: 74775 pass(es) in 0.309299 seconds
-fself-test: 74775 pass(es) in 0.366041 seconds
-fself-test: 74775 pass(es) in 0.356663 seconds
-fself-test: 74775 pass(es) in 0.355009 seconds
-fself-test: 74775 pass(es) in 0.367575 seconds
-fself-test: 74775 pass(es) in 0.320406 seconds
..., and with my changes we've got:
-fself-test: 94519 pass(es) in 0.327755 seconds
-fself-test: 94519 pass(es) in 0.369522 seconds
-fself-test: 94519 pass(es) in 0.355531 seconds
-fself-test: 94519 pass(es) in 0.362179 seconds
-fself-test: 94519 pass(es) in 0.363176 seconds
-fself-test: 94519 pass(es) in 0.318930 seconds
So it really seems to be all in the noise?
Yet:
> Selftests run each time GCC
> builds (i.e., even during day to day development). It seems to me
> that it might be better to run such selftests only as part of
> the bootstrap process.
I'd rather have thought about a '--param self-test-expensive' (or
similar), and then invoke the selftests via a new
'gcc/testsuite/selftests/expensive.exp' (or similar).
Or, adapt 'gcc/testsuite/gcc.dg/plugin/expensive_selftests_plugin.c',
that is, invoke them via the GCC plugin mechanism, which also seems to be
easy enough?
I don't have a strong opinion about where/when these tests get run, so
will happily take any suggestions.
Grüße
Thomas
-----------------
Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634
München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas
Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht
München, HRB 106955
>From 12fda2ece45ea477cdc9a697b5efc6e51c9da229 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <tho...@codesourcery.com>
Date: Fri, 13 Aug 2021 17:53:12 +0200
Subject: [PATCH] Add more self-tests for 'hash_map' with Value type with
non-trivial constructor/destructor
... to document the current behavior.
gcc/
* hash-map-tests.c (test_map_of_type_with_ctor_and_dtor): Extend.
(test_map_of_type_with_ctor_and_dtor_expand): Add function.
(hash_map_tests_c_tests): Call it.
---
gcc/hash-map-tests.c | 142 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 142 insertions(+)
diff --git a/gcc/hash-map-tests.c b/gcc/hash-map-tests.c
index 5b6b192cd28..3c79a13c1a8 100644
--- a/gcc/hash-map-tests.c
+++ b/gcc/hash-map-tests.c
@@ -278,6 +278,146 @@ test_map_of_type_with_ctor_and_dtor ()
ASSERT_TRUE (val_t::ndefault + val_t::ncopy == val_t::ndtor);
}
+
+
+ /* Verify basic construction and destruction of Value objects. */
+ {
+ const int N_elem = 1234;
+ void *a[N_elem];
+ for (int i = 0; i < N_elem; ++i)
+ a[i] = &a[i];
+
+ const int N_init = 44;
+
+ val_t::ndefault = 0;
+ val_t::ncopy = 0;
+ val_t::nassign = 0;
+ val_t::ndtor = 0;
+ Map m (N_init);
+ ASSERT_EQ (val_t::ndefault
+ + val_t::ncopy
+ + val_t::nassign
+ + val_t::ndtor, 0);
+
+ for (int i = 0; i < N_elem; ++i)
+ {
+ m.get_or_insert (a[i]);
+ ASSERT_EQ (val_t::ndefault, 1 + i);
+ ASSERT_EQ (val_t::ncopy, 0);
+ ASSERT_EQ (val_t::nassign, 0);
+ ASSERT_EQ (val_t::ndtor, i);
+
+ m.remove (a[i]);
+ ASSERT_EQ (val_t::ndefault, 1 + i);
+ ASSERT_EQ (val_t::ncopy, 0);
+ ASSERT_EQ (val_t::nassign, 0);
+ ASSERT_EQ (val_t::ndtor, 1 + i);
+ }
+ }
+}
+
+/* Verify 'hash_table::expand'. */
+
+static void
+test_map_of_type_with_ctor_and_dtor_expand (bool remove_some_inline)
+{
+ typedef hash_map <void *, val_t> Map;
+
+ /* Note that we are starting with a fresh 'Map'. Even if an existing one has
+ been cleared out completely, there remain 'deleted' elements, and these
+ would disturb the following logic, where we don't have access to the
+ actual 'm_n_deleted' value. */
+ size_t m_n_deleted = 0;
+
+ const int N_elem = 1234;
+ void *a[N_elem];
+ for (int i = 0; i < N_elem; ++i)
+ a[i] = &a[i];
+
+ const int N_init = 4;
+
+ val_t::ndefault = 0;
+ val_t::ncopy = 0;
+ val_t::nassign = 0;
+ val_t::ndtor = 0;
+ Map m (N_init);
+
+ /* In the following, in particular related to 'expand', we're adapting from
+ the internal logic of 'hash_table', glossing over "some details" not
+ relevant for this testing here. */
+
+ size_t m_size;
+ {
+ unsigned int size_prime_index_ = hash_table_higher_prime_index (N_init);
+ m_size = prime_tab[size_prime_index_].prime;
+ }
+ int n_expand_moved = 0;
+
+ for (int i = 0; i < N_elem; ++i)
+ {
+ int elts = m.elements ();
+
+ /* Per 'hash_table::find_slot_with_hash'. */
+ size_t m_n_elements = elts + m_n_deleted;
+ bool expand = m_size * 3 <= m_n_elements * 4;
+ m.get_or_insert (a[i]);
+ if (expand)
+ {
+ /* Per 'hash_table::expand'. */
+ {
+ unsigned int nindex = hash_table_higher_prime_index (elts * 2);
+ m_size = prime_tab[nindex].prime;
+ }
+ m_n_deleted = 0;
+
+ /* All non-deleted elements have been moved. */
+ n_expand_moved += i;
+ if (remove_some_inline)
+ n_expand_moved -= (i + 2) / 3;
+ }
+
+ ASSERT_EQ (val_t::ndefault, 1 + i);
+ ASSERT_EQ (val_t::ncopy, n_expand_moved);
+ ASSERT_EQ (val_t::nassign, 0);
+ if (remove_some_inline)
+ ASSERT_EQ (val_t::ndtor, (i + 2) / 3);
+ else
+ ASSERT_EQ (val_t::ndtor, 0);
+
+ /* Remove some inline. This never triggers an 'expand', but does
+ influence any following via 'm_n_deleted'. */
+ if (remove_some_inline
+ && !(i % 3))
+ {
+ m.remove (a[i]);
+ /* Per 'hash_table::remove_elt_with_hash'. */
+ m_n_deleted++;
+
+ ASSERT_EQ (val_t::ndefault, 1 + i);
+ ASSERT_EQ (val_t::ncopy, n_expand_moved);
+ ASSERT_EQ (val_t::nassign, 0);
+ ASSERT_EQ (val_t::ndtor, 1 + (i + 2) / 3);
+ }
+ }
+
+ int ndefault = val_t::ndefault;
+ int ncopy = val_t::ncopy;
+ int nassign = val_t::nassign;
+ int ndtor = val_t::ndtor;
+
+ for (int i = 0; i < N_elem; ++i)
+ {
+ if (remove_some_inline
+ && !(i % 3))
+ continue;
+
+ m.remove (a[i]);
+ ++ndtor;
+ ASSERT_EQ (val_t::ndefault, ndefault);
+ ASSERT_EQ (val_t::ncopy, ncopy);
+ ASSERT_EQ (val_t::nassign, nassign);
+ ASSERT_EQ (val_t::ndtor, ndtor);
+ }
}
/* Test calling empty on a hash_map that has a key type with non-zero
@@ -309,6 +449,8 @@ hash_map_tests_c_tests ()
test_map_of_strings_to_int ();
test_map_of_int_to_strings ();
test_map_of_type_with_ctor_and_dtor ();
+ test_map_of_type_with_ctor_and_dtor_expand (false);
+ test_map_of_type_with_ctor_and_dtor_expand (true);
test_nonzero_empty_key ();
}
--
2.30.2
