diff options
| author | Jason Merrill <jason@redhat.com> | 2021-01-22 13:17:10 -0500 |
|---|---|---|
| committer | Jason Merrill <jason@redhat.com> | 2021-01-25 10:36:27 -0500 |
| commit | 94ff4c9dd98f39280fba22d1ad0958fb25a5363b (patch) | |
| tree | ab662beb03a2eb1997cef9866d0c14c4d3f5f3b4 /gcc/cp | |
| parent | 10c83fb7131779ee27fbaa9091065ca6cfedc0c5 (diff) | |
| download | gcc-94ff4c9dd98f39280fba22d1ad0958fb25a5363b.zip gcc-94ff4c9dd98f39280fba22d1ad0958fb25a5363b.tar.gz gcc-94ff4c9dd98f39280fba22d1ad0958fb25a5363b.tar.bz2 | |
c++: [[no_unique_address]] in empty base [PR98463]
In this testcase, cxx_eval_store_expression got confused trying to build up
CONSTRUCTORs for initializing a subobject because the subobject is a member
of an empty base. In C++14 mode and below we don't build FIELD_DECLs for
empty bases, so the CONSTRUCTOR skipped the empty base, and treated the
member as a member of the derived class, which breaks.
Fixed by recognizing this situation and giving up on trying to build a
CONSTRUCTOR for the inner target at that point; since it doesn't have any
data, we don't need to actually store anything.
gcc/cp/ChangeLog:
PR c++/98463
* constexpr.c (get_or_insert_ctor_field): Add check.
(cxx_eval_store_expression): Handle discontinuity of refs.
gcc/testsuite/ChangeLog:
PR c++/98463
* g++.dg/cpp2a/no_unique_address8.C: New test.
Diffstat (limited to 'gcc/cp')
| -rw-r--r-- | gcc/cp/constexpr.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index b787919..c121753 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -3474,7 +3474,9 @@ get_or_insert_ctor_field (tree ctor, tree index, int pos_hint = -1) } else { - gcc_assert (TREE_CODE (index) == FIELD_DECL); + gcc_assert (TREE_CODE (index) == FIELD_DECL + && (same_type_ignoring_top_level_qualifiers_p + (DECL_CONTEXT (index), TREE_TYPE (ctor)))); /* We must keep the CONSTRUCTOR's ELTS in FIELD order. Usually we meet initializers in that order, but it is @@ -5277,7 +5279,7 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, }; CONSTRUCTOR_ELTS (ary_ctor)->quick_push (elt); } - + *valp = ary_ctor; } @@ -5289,6 +5291,18 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, type = refs->pop(); tree index = refs->pop(); + if (TREE_CODE (index) == FIELD_DECL + && !(same_type_ignoring_top_level_qualifiers_p + (DECL_CONTEXT (index), TREE_TYPE (*valp)))) + { + /* INDEX isn't a member of *valp. This can happen if it's a member + of an empty base which isn't represented with a FIELD_DECL. Stop + trying to build a CONSTRUCTOR for the inner target; we'll notice + this disconnect again below and just return init. */ + gcc_assert (is_empty_class (DECL_CONTEXT (index))); + break; + } + if (code == UNION_TYPE && CONSTRUCTOR_NELTS (*valp) && CONSTRUCTOR_ELT (*valp, 0)->index != index) { |