From 610ae2dbbf98a291782cb05c0fb31e056193e5e2 Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Wed, 20 May 2020 09:15:48 -0400 Subject: c++: spec_hasher and TYPENAME_TYPE resolution [PR95223] After enabling sanitization of the specialization tables, we are triggering one of the hash table sanity checks in the below testcase. The reason is that when looking up the specialization j in the type_specializations table, the sanity check finds that the existing entry j::m> compares equal to j but hashes differently. The discrepancy is due to structural_comptypes looking through TYPENAME_TYPEs (via resolve_typename_type), something which iterative_hash_template_arg doesn't do. So the TYPENAME_TYPE n::m is considered equal to int, but the hashes of these two template arguments are different. It seems wrong for the result of a specialization table lookup to depend on the current scope, so this patch makes structural_comptypes avoid calling resolve_typename_type when comparing_specializations. In order for the below testcase to deterministically trigger the sanitization error without this patch, we also need to fix the location of the call to hash_table::verify within hash_table::find_with_hash. gcc/ChangeLog: PR c++/95223 * hash-table.h (hash_table::find_with_hash): Move up the call to hash_table::verify. gcc/cp/ChangeLog: PR c++/95223 * typeck.c (structural_comptypes): Don't perform context-dependent resolution of TYPENAME_TYPEs when comparing_specializations. gcc/testsuite/ChangeLog: PR c++/95223 * g++.dg/template/typename23.C: New test. --- gcc/hash-table.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'gcc/hash-table.h') diff --git a/gcc/hash-table.h b/gcc/hash-table.h index a1423c7..32f3a63 100644 --- a/gcc/hash-table.h +++ b/gcc/hash-table.h @@ -912,6 +912,12 @@ hash_table if (Lazy && m_entries == NULL) m_entries = alloc_entries (size); + +#if CHECKING_P + if (m_sanitize_eq_and_hash) + verify (comparable, hash); +#endif + value_type *entry = &m_entries[index]; if (is_empty (*entry) || (!is_deleted (*entry) && Descriptor::equal (*entry, comparable))) @@ -928,13 +934,7 @@ hash_table entry = &m_entries[index]; if (is_empty (*entry) || (!is_deleted (*entry) && Descriptor::equal (*entry, comparable))) - { -#if CHECKING_P - if (m_sanitize_eq_and_hash) - verify (comparable, hash); -#endif - return *entry; - } + return *entry; } } -- cgit v1.1