[PATCH v18 23/26] c++: Implement __is_invocable built-in trait
Jason Merrill
jason@redhat.com
Thu May 2 20:38:16 GMT 2024
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 <kmatsui@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 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.
> + && (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.
Jason
> + /* 1.3 & 1.6: Try to dereference datum_expr. */
> + datum_expr = build_x_indirect_ref (UNKNOWN_LOCATION, datum_expr,
> + RO_UNARY_STAR, NULL_TREE, complain);
> + /* 1.1, 1.2, 1.4, & 1.5: Otherwise. */
> +
> + tree fn_expr = build_trait_object (fn_type);
> + ptrmem_expr = build_m_component_ref (datum_expr, fn_expr, complain);
> +
> + if (error_operand_p (ptrmem_expr))
> + return error_mark_node;
> +
> + if (is_ptrdatamem)
> + return ptrmem_expr;
> + }
> +
> + /* Construct expressions for arguments to INVOKE. For a pointer to member
> + function, the first argument, which is the object, is not arguments to
> + the function. */
> + releasing_vec args;
> + for (int i = is_ptrmemfunc ? 1 : 0; i < TREE_VEC_LENGTH (arg_types); ++i)
> + {
> + tree arg_type = TREE_VEC_ELT (arg_types, i);
> + tree arg = build_trait_object (arg_type);
> + vec_safe_push (args, arg);
> + }
> +
> + tree invoke_expr;
> + if (is_ptrmemfunc)
> + invoke_expr = build_offset_ref_call_from_tree (ptrmem_expr, &args,
> + complain);
> + else /* 1.7. */
> + invoke_expr = finish_call_expr (build_trait_object (fn_type), &args, false,
> + false, complain);
> + return invoke_expr;
> +}
> +
> /* Determine which function will be called when looking up NAME in TYPE,
> called with a single ARGTYPE argument, or no argument if ARGTYPE is
> null. FLAGS and COMPLAIN are as for build_new_method_call.
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