On Thu, May 2, 2024 at 7:43 PM Jason Merrill <ja...@redhat.com> wrote:
>
> On 5/2/24 16:47, Ken Matsui wrote:
> > On Thu, May 2, 2024 at 1:38 PM Jason Merrill <ja...@redhat.com> wrote:
> >>
> >> On 5/2/24 16:12, Ken Matsui wrote:
> >>> This patch implements built-in trait for std::is_invocable.
> >>>
> >>> gcc/cp/ChangeLog:
> >>>
> >>> * cp-trait.def: Define __is_invocable.
> >>> * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_INVOCABLE.
> >>> * semantics.cc (trait_expr_value): Likewise.
> >>> (finish_trait_expr): Likewise.
> >>> * cp-tree.h (build_invoke): New function.
> >>> * method.cc (build_invoke): New function.
> >>>
> >>> gcc/testsuite/ChangeLog:
> >>>
> >>> * g++.dg/ext/has-builtin-1.C: Test existence of __is_invocable.
> >>> * g++.dg/ext/is_invocable1.C: New test.
> >>> * g++.dg/ext/is_invocable2.C: New test.
> >>> * g++.dg/ext/is_invocable3.C: New test.
> >>> * g++.dg/ext/is_invocable4.C: New test.
> >>>
> >>> Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
> >>> ---
> >>> gcc/cp/constraint.cc | 6 +
> >>> gcc/cp/cp-trait.def | 1 +
> >>> gcc/cp/cp-tree.h | 2 +
> >>> gcc/cp/method.cc | 134 +++++++++
> >>> gcc/cp/semantics.cc | 5 +
> >>> gcc/testsuite/g++.dg/ext/has-builtin-1.C | 3 +
> >>> gcc/testsuite/g++.dg/ext/is_invocable1.C | 349 +++++++++++++++++++++++
> >>> gcc/testsuite/g++.dg/ext/is_invocable2.C | 139 +++++++++
> >>> gcc/testsuite/g++.dg/ext/is_invocable3.C | 51 ++++
> >>> gcc/testsuite/g++.dg/ext/is_invocable4.C | 33 +++
> >>> 10 files changed, 723 insertions(+)
> >>> create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable1.C
> >>> create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable2.C
> >>> create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable3.C
> >>> create mode 100644 gcc/testsuite/g++.dg/ext/is_invocable4.C
> >>>
> >>> diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> >>> index c28d7bf428e..6d14ef7dcc7 100644
> >>> --- a/gcc/cp/constraint.cc
> >>> +++ b/gcc/cp/constraint.cc
> >>> @@ -3792,6 +3792,12 @@ diagnose_trait_expr (tree expr, tree args)
> >>> case CPTK_IS_FUNCTION:
> >>> inform (loc, " %qT is not a function", t1);
> >>> break;
> >>> + case CPTK_IS_INVOCABLE:
> >>> + if (!t2)
> >>> + inform (loc, " %qT is not invocable", t1);
> >>> + else
> >>> + inform (loc, " %qT is not invocable by %qE", t1, t2);
> >>> + break;
> >>> case CPTK_IS_LAYOUT_COMPATIBLE:
> >>> inform (loc, " %qT is not layout compatible with %qT", t1, t2);
> >>> break;
> >>> diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> >>> index b1c875a6e7d..4e420d5390a 100644
> >>> --- a/gcc/cp/cp-trait.def
> >>> +++ b/gcc/cp/cp-trait.def
> >>> @@ -75,6 +75,7 @@ DEFTRAIT_EXPR (IS_EMPTY, "__is_empty", 1)
> >>> DEFTRAIT_EXPR (IS_ENUM, "__is_enum", 1)
> >>> DEFTRAIT_EXPR (IS_FINAL, "__is_final", 1)
> >>> DEFTRAIT_EXPR (IS_FUNCTION, "__is_function", 1)
> >>> +DEFTRAIT_EXPR (IS_INVOCABLE, "__is_invocable", -1)
> >>> DEFTRAIT_EXPR (IS_LAYOUT_COMPATIBLE, "__is_layout_compatible", 2)
> >>> DEFTRAIT_EXPR (IS_LITERAL_TYPE, "__is_literal_type", 1)
> >>> DEFTRAIT_EXPR (IS_MEMBER_FUNCTION_POINTER,
> >>> "__is_member_function_pointer", 1)
> >>> diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
> >>> index 1938ada0268..83dc20e1130 100644
> >>> --- a/gcc/cp/cp-tree.h
> >>> +++ b/gcc/cp/cp-tree.h
> >>> @@ -7338,6 +7338,8 @@ extern tree get_copy_assign
> >>> (tree);
> >>> extern tree get_default_ctor (tree);
> >>> extern tree get_dtor (tree,
> >>> tsubst_flags_t);
> >>> extern tree build_stub_object (tree);
> >>> +extern tree build_invoke (tree, const_tree,
> >>> + tsubst_flags_t);
> >>> extern tree strip_inheriting_ctors (tree);
> >>> extern tree inherited_ctor_binfo (tree);
> >>> extern bool base_ctor_omit_inherited_parms (tree);
> >>> diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
> >>> index 08a3d34fb01..faf932258e6 100644
> >>> --- a/gcc/cp/method.cc
> >>> +++ b/gcc/cp/method.cc
> >>> @@ -1928,6 +1928,140 @@ build_trait_object (tree type)
> >>> return build_stub_object (type);
> >>> }
> >>>
> >>> +/* [func.require] Build an expression of INVOKE(FN_TYPE, ARG_TYPES...).
> >>> If the
> >>> + given is not invocable, returns error_mark_node. */
> >>> +
> >>> +tree
> >>> +build_invoke (tree fn_type, const_tree arg_types, tsubst_flags_t
> >>> complain)
> >>> +{
> >>> + if (error_operand_p (fn_type) || error_operand_p (arg_types))
> >>> + return error_mark_node;
> >>> +
> >>> + gcc_assert (TYPE_P (fn_type));
> >>> + gcc_assert (TREE_CODE (arg_types) == TREE_VEC);
> >>> +
> >>> + /* Access check is required to determine if the given is invocable. */
> >>> + deferring_access_check_sentinel acs (dk_no_deferred);
> >>> +
> >>> + /* INVOKE is an unevaluated context. */
> >>> + cp_unevaluated cp_uneval_guard;
> >>> +
> >>> + bool is_ptrdatamem;
> >>> + bool is_ptrmemfunc;
> >>> + if (TREE_CODE (fn_type) == REFERENCE_TYPE)
> >>> + {
> >>> + tree deref_fn_type = TREE_TYPE (fn_type);
> >>> + is_ptrdatamem = TYPE_PTRDATAMEM_P (deref_fn_type);
> >>> + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (deref_fn_type);
> >>> +
> >>> + /* Dereference fn_type if it is a pointer to member. */
> >>> + if (is_ptrdatamem || is_ptrmemfunc)
> >>> + fn_type = deref_fn_type;
> >>> + }
> >>> + else
> >>> + {
> >>> + is_ptrdatamem = TYPE_PTRDATAMEM_P (fn_type);
> >>> + is_ptrmemfunc = TYPE_PTRMEMFUNC_P (fn_type);
> >>> + }
> >>> +
> >>> + if (is_ptrdatamem && TREE_VEC_LENGTH (arg_types) != 1)
> >>> + {
> >>> + if (complain & tf_error)
> >>> + error ("pointer to data member type %qT can only be invoked with "
> >>> + "one argument", fn_type);
> >>> + return error_mark_node;
> >>> + }
> >>> +
> >>> + if (is_ptrmemfunc && TREE_VEC_LENGTH (arg_types) == 0)
> >>> + {
> >>> + if (complain & tf_error)
> >>> + error ("pointer to member function type %qT must be invoked with "
> >>> + "at least one argument", fn_type);
> >>> + return error_mark_node;
> >>> + }
> >>> +
> >>> + /* Construct an expression of a pointer to member. */
> >>> + tree ptrmem_expr;
> >>> + if (is_ptrdatamem || is_ptrmemfunc)
> >>> + {
> >>> + tree datum_type = TREE_VEC_ELT (arg_types, 0);
> >>> +
> >>> + /* datum must be a class type or a reference/pointer to a class
> >>> type. */
> >>> + if (!(CLASS_TYPE_P (datum_type)
> >>> + || ((TYPE_REF_P (datum_type) || POINTER_TYPE_P (datum_type))
> >>> + && CLASS_TYPE_P (TREE_TYPE (datum_type)))))
> >>> + {
> >>> + if (complain & tf_error)
> >>> + error ("first argument type %qT of a pointer to member must be"
> >>> + "a class type or a reference/pointer to a class type",
> >>> + datum_type);
> >>> + return error_mark_node;
> >>> + }
> >>> +
> >>> + bool is_refwrap = false;
> >>> + if (CLASS_TYPE_P (datum_type))
> >>> + {
> >>> + /* 1.2 & 1.5: Handle std::reference_wrapper. */
> >>> + tree datum_decl = TYPE_NAME (TYPE_MAIN_VARIANT (datum_type));
> >>> + if (decl_in_std_namespace_p (datum_decl))
> >>> + {
> >>> + const_tree name = DECL_NAME (datum_decl);
> >>> + if (name && (id_equal (name, "reference_wrapper")))
> >>> + {
> >>> + /* Retrieve T from std::reference_wrapper<T>,
> >>> + i.e., decltype(datum.get()). */
> >>> + datum_type = TREE_VEC_ELT (TYPE_TI_ARGS (datum_type), 0);
> >>> + is_refwrap = true;
> >>> + }
> >>> + }
> >>> + }
> >>> +
> >>> + tree ptrmem_class_type = TYPE_PTRMEM_CLASS_TYPE (fn_type);
> >>> + const bool ptrmem_is_base_of_datum =
> >>> + (NON_UNION_CLASS_TYPE_P (ptrmem_class_type)
> >>> + && NON_UNION_CLASS_TYPE_P (datum_type)
> >>
> >> Why NON_UNION? That doesn't seem to be based on anything in the standard.
> >
> > This comes from the __is_base_of implementation in semantics.cc:
> >
> > case CPTK_IS_BASE_OF:
> > return (NON_UNION_CLASS_TYPE_P (type1) && NON_UNION_CLASS_TYPE_P
> > (type2)
> > && (same_type_ignoring_top_level_qualifiers_p (type1, type2)
> > || DERIVED_FROM_P (type1, type2)));
>
> OK, but non-union isn't a requirement for is_same, but you're applying
> that requirement for the same-type case as well as for the base case.
>
> >> This check and the one for reference_wrapper need to ignore
> >> REFERENCE_TYPE; INVOKE is defined in terms of expressions, and the type
> >> of an expression is never a reference.
>
> > I think ptrmem_is_base_of_datum and is_refwrap checks are ignoring
> > REFERENCE_TYPE, leading to false, ...
>
> I mean they need to look through REFERENCE_TYPE; if the first argument
> is reference to reference_wrapper, we need to use the reference_wrapper
> handling. Likewise if it's a reference to T or a base of T.
>
> >>> + && (same_type_ignoring_top_level_qualifiers_p (ptrmem_class_type,
> >>> + datum_type)
> >>> + || DERIVED_FROM_P (ptrmem_class_type, datum_type)));
> >>> +
> >>> + tree datum_expr = build_trait_object (datum_type);
> >>> + if (!ptrmem_is_base_of_datum && !is_refwrap && !TYPE_REF_P
> >>> (datum_type))
> >>
> >> ...so we shouldn't need to check TYPE_REF_P here.
>
> > ... which is why I think we need to check TYPE_REF_P here.
>
> The standard says that if t1 isn't either same, base, or
> reference_wrapper, we dereference it. There's no exception for
> references because they shouldn't get this far.
Oh, that makes sense! Thank you so much for your review!
>
> Jason
>
