From 610ae2dbbf98a291782cb05c0fb31e056193e5e2 Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Wed, 20 May 2020 09:15:48 -0400 Subject: [PATCH] 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/ChangeLog | 6 ++++++ gcc/cp/ChangeLog | 7 +++++++ gcc/cp/typeck.c | 15 +++++++++------ gcc/hash-table.h | 14 +++++++------- gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/g++.dg/template/typename23.C | 10 ++++++++++ 6 files changed, 44 insertions(+), 13 deletions(-) create mode 100644 gcc/testsuite/g++.dg/template/typename23.C diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2fe9f0dfdf5..cef2e7bfd03 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2020-05-20 Patrick Palka + + PR c++/95223 + * hash-table.h (hash_table::find_with_hash): Move up the call to + hash_table::verify. + 2020-05-20 Martin Liska * lto-compress.c (lto_compression_zstd): Fill up diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index a81a6200ff5..c59137faa3f 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,10 @@ +2020-05-20 Patrick Palka + + PR c++/95223 + * typeck.c (structural_comptypes): Don't perform + context-dependent resolution of TYPENAME_TYPEs when + comparing_specializations. + 2020-05-19 Nathan Sidwell * pt.c (lookup_template_class_1): Do not reinit template_info of an diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c index d2e6c907622..0181984bb99 100644 --- a/gcc/cp/typeck.c +++ b/gcc/cp/typeck.c @@ -1256,13 +1256,16 @@ structural_comptypes (tree t1, tree t2, int strict) gcc_assert (TYPE_P (t1) && TYPE_P (t2)); - /* TYPENAME_TYPEs should be resolved if the qualifying scope is the - current instantiation. */ - if (TREE_CODE (t1) == TYPENAME_TYPE) - t1 = resolve_typename_type (t1, /*only_current_p=*/true); + if (!comparing_specializations) + { + /* TYPENAME_TYPEs should be resolved if the qualifying scope is the + current instantiation. */ + if (TREE_CODE (t1) == TYPENAME_TYPE) + t1 = resolve_typename_type (t1, /*only_current_p=*/true); - if (TREE_CODE (t2) == TYPENAME_TYPE) - t2 = resolve_typename_type (t2, /*only_current_p=*/true); + if (TREE_CODE (t2) == TYPENAME_TYPE) + t2 = resolve_typename_type (t2, /*only_current_p=*/true); + } if (TYPE_PTRMEMFUNC_P (t1)) t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1); diff --git a/gcc/hash-table.h b/gcc/hash-table.h index a1423c78112..32f3a634e1e 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; } } diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 49f8cd7cf9c..3594d01cb93 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-05-20 Patrick Palka + + PR c++/95223 + * g++.dg/template/typename23.C: New test. + 2020-05-20 Srinath Parvathaneni PR target/94959 diff --git a/gcc/testsuite/g++.dg/template/typename23.C b/gcc/testsuite/g++.dg/template/typename23.C new file mode 100644 index 00000000000..d2fb0ca72f5 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/typename23.C @@ -0,0 +1,10 @@ +// PR c++/95223 +// { dg-do compile } +// { dg-additional-options "--param=hash-table-verification-limit=10000" } + +template struct j {}; +template struct n { + typedef int m; + j::m> p(); +}; +template j::m> n::p() { return o::f(); } -- 2.30.2