diff options
| author | Patrick Palka <ppalka@redhat.com> | 2020-05-20 09:15:48 -0400 |
|---|---|---|
| committer | Patrick Palka <ppalka@redhat.com> | 2020-05-20 09:15:48 -0400 |
| commit | 610ae2dbbf98a291782cb05c0fb31e056193e5e2 (patch) | |
| tree | f5edf193aa25d5def8c3a2ab87a7ac47912ca9dd /gcc/cp | |
| parent | 053dc901e0227bb62b65f3a8d7a9deccb61dffa1 (diff) | |
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<int> in the
type_specializations table, the sanity check finds that the existing
entry j<n<t>::m> compares equal to j<int> 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<t>::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.
Diffstat (limited to 'gcc/cp')
| -rw-r--r-- | gcc/cp/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/cp/typeck.c | 15 |
2 files changed, 16 insertions, 6 deletions
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 <ppalka@redhat.com> + + PR c++/95223 + * typeck.c (structural_comptypes): Don't perform + context-dependent resolution of TYPENAME_TYPEs when + comparing_specializations. + 2020-05-19 Nathan Sidwell <nathan@acm.org> * 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); |