From: Jason Merrill <jason@redhat.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] c++: Implement C++23 P2589R1 - - static operator[]
Date: Mon, 14 Nov 2022 18:29:44 -0500 [thread overview]
Message-ID: <1ec099de-4247-29ec-0e06-602a90370388@redhat.com> (raw)
In-Reply-To: <Y238ewF+UgXC2kFk@tucnak>
On 11/10/22 21:40, Jakub Jelinek wrote:
> Hi!
>
> As stage1 is very close, here is a patch that implements the static
> operator[] paper.
> One thing that doesn't work properly is the same problem as I've filed
> yesterday for static operator() - PR107624 - that side-effects of
> the postfix-expression on which the call or subscript operator are
> applied are thrown away, I assume we have to add them into COMPOUND_EXPR
> somewhere after we find out that the we've chosen a static member function
> operator.
Indeed. The code in build_new_method_call for this case has the comment
/* In an expression of the form `a->f()' where `f' turns
out to be a static member function, `a' is
none-the-less evaluated. */
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk
> provided the paper gets voted into C++23?
OK.
> 2022-11-11 Jakub Jelinek <jakub@redhat.com>
>
> gcc/c-family/
> * c-cppbuiltin.cc (c_cpp_builtins): Bump C++23
> __cpp_multidimensional_subscript macro value to 202211L.
> gcc/cp/
> * decl.cc (grok_op_properties): Implement C++23 P2589R1
> - static operator[]. Handle operator[] similarly to operator()
> - allow static member functions, but pedwarn on it for C++20 and
> older. Unlike operator(), perform rest of checks on it though for
> C++20.
> * call.cc (add_operator_candidates): For operator[] with class
> typed first parameter, pass that parameter as first_arg and
> an adjusted arglist without that parameter.
> gcc/testsuite/
> * g++.dg/cpp23/subscript9.C: New test.
> * g++.dg/cpp23/feat-cxx2b.C: Expect a newer
> __cpp_multidimensional_subscript value.
> * g++.old-deja/g++.bugs/900210_10.C: Don't expect an error
> for C++23 or later.
>
> --- gcc/c-family/c-cppbuiltin.cc.jj 2022-10-14 09:35:56.182990495 +0200
> +++ gcc/c-family/c-cppbuiltin.cc 2022-11-10 22:29:12.539832741 +0100
> @@ -1075,7 +1075,7 @@ c_cpp_builtins (cpp_reader *pfile)
> cpp_define (pfile, "__cpp_size_t_suffix=202011L");
> cpp_define (pfile, "__cpp_if_consteval=202106L");
> cpp_define (pfile, "__cpp_constexpr=202110L");
> - cpp_define (pfile, "__cpp_multidimensional_subscript=202110L");
> + cpp_define (pfile, "__cpp_multidimensional_subscript=202211L");
> cpp_define (pfile, "__cpp_named_character_escapes=202207L");
> cpp_define (pfile, "__cpp_static_call_operator=202207L");
> cpp_define (pfile, "__cpp_implicit_move=202207L");
> --- gcc/cp/decl.cc.jj 2022-11-08 09:54:37.313400209 +0100
> +++ gcc/cp/decl.cc 2022-11-10 21:26:06.891359343 +0100
> @@ -15377,7 +15377,15 @@ grok_op_properties (tree decl, bool comp
> an enumeration, or a reference to an enumeration. 13.4.0.6 */
> if (! methodp || DECL_STATIC_FUNCTION_P (decl))
> {
> - if (operator_code == CALL_EXPR)
> + if (operator_code == TYPE_EXPR
> + || operator_code == COMPONENT_REF
> + || operator_code == NOP_EXPR)
> + {
> + error_at (loc, "%qD must be a non-static member function", decl);
> + return false;
> + }
> +
> + if (operator_code == CALL_EXPR || operator_code == ARRAY_REF)
> {
> if (! DECL_STATIC_FUNCTION_P (decl))
> {
> @@ -15386,52 +15394,41 @@ grok_op_properties (tree decl, bool comp
> }
> if (cxx_dialect < cxx23
> /* For lambdas we diagnose static lambda specifier elsewhere. */
> - && ! LAMBDA_FUNCTION_P (decl)
> + && (operator_code == ARRAY_REF || ! LAMBDA_FUNCTION_P (decl))
> /* For instantiations, we have diagnosed this already. */
> && ! DECL_USE_TEMPLATE (decl))
> pedwarn (loc, OPT_Wc__23_extensions, "%qD may be a static member "
> - "function only with %<-std=c++23%> or %<-std=gnu++23%>", decl);
> - /* There are no further restrictions on the arguments to an
> - overloaded "operator ()". */
> - return true;
> - }
> - if (operator_code == TYPE_EXPR
> - || operator_code == COMPONENT_REF
> - || operator_code == ARRAY_REF
> - || operator_code == NOP_EXPR)
> - {
> - error_at (loc, "%qD must be a non-static member function", decl);
> - return false;
> + "function only with %<-std=c++23%> or %<-std=gnu++23%>",
> + decl);
> }
> -
> - if (DECL_STATIC_FUNCTION_P (decl))
> + else if (DECL_STATIC_FUNCTION_P (decl))
> {
> error_at (loc, "%qD must be either a non-static member "
> "function or a non-member function", decl);
> return false;
> }
> -
> - for (tree arg = argtypes; ; arg = TREE_CHAIN (arg))
> - {
> - if (!arg || arg == void_list_node)
> - {
> - if (complain)
> - error_at(loc, "%qD must have an argument of class or "
> - "enumerated type", decl);
> - return false;
> - }
> + else
> + for (tree arg = argtypes; ; arg = TREE_CHAIN (arg))
> + {
> + if (!arg || arg == void_list_node)
> + {
> + if (complain)
> + error_at (loc, "%qD must have an argument of class or "
> + "enumerated type", decl);
> + return false;
> + }
>
> - tree type = non_reference (TREE_VALUE (arg));
> - if (type == error_mark_node)
> - return false;
> -
> - /* MAYBE_CLASS_TYPE_P, rather than CLASS_TYPE_P, is used
> - because these checks are performed even on template
> - functions. */
> - if (MAYBE_CLASS_TYPE_P (type)
> - || TREE_CODE (type) == ENUMERAL_TYPE)
> - break;
> - }
> + tree type = non_reference (TREE_VALUE (arg));
> + if (type == error_mark_node)
> + return false;
> +
> + /* MAYBE_CLASS_TYPE_P, rather than CLASS_TYPE_P, is used
> + because these checks are performed even on template
> + functions. */
> + if (MAYBE_CLASS_TYPE_P (type)
> + || TREE_CODE (type) == ENUMERAL_TYPE)
> + break;
> + }
> }
>
> if (operator_code == CALL_EXPR)
> --- gcc/cp/call.cc.jj 2022-11-08 09:54:37.283400616 +0100
> +++ gcc/cp/call.cc 2022-11-10 22:26:38.096936491 +0100
> @@ -6589,12 +6589,36 @@ add_operator_candidates (z_candidate **c
> if (fns == error_mark_node)
> return error_mark_node;
> if (fns)
> - add_candidates (BASELINK_FUNCTIONS (fns),
> - NULL_TREE, arglist, NULL_TREE,
> - NULL_TREE, false,
> - BASELINK_BINFO (fns),
> - BASELINK_ACCESS_BINFO (fns),
> - flags, candidates, complain);
> + {
> + if (code == ARRAY_REF)
> + {
> + vec<tree,va_gc> *restlist = make_tree_vector ();
> + for (unsigned i = 1; i < nargs; ++i)
> + vec_safe_push (restlist, (*arglist)[i]);
> + z_candidate *save_cand = *candidates;
> + add_candidates (BASELINK_FUNCTIONS (fns),
> + (*arglist)[0], restlist, NULL_TREE,
> + NULL_TREE, false,
> + BASELINK_BINFO (fns),
> + BASELINK_ACCESS_BINFO (fns),
> + flags, candidates, complain);
> + /* Release the vec if we didn't add a candidate that uses it. */
> + for (z_candidate *c = *candidates; c != save_cand; c = c->next)
> + if (c->args == restlist)
> + {
> + restlist = NULL;
> + break;
> + }
> + release_tree_vector (restlist);
> + }
> + else
> + add_candidates (BASELINK_FUNCTIONS (fns),
> + NULL_TREE, arglist, NULL_TREE,
> + NULL_TREE, false,
> + BASELINK_BINFO (fns),
> + BASELINK_ACCESS_BINFO (fns),
> + flags, candidates, complain);
> + }
> }
> /* Per [over.match.oper]3.2, if no operand has a class type, then
> only non-member functions that have type T1 or reference to
> --- gcc/testsuite/g++.dg/cpp23/subscript9.C.jj 2022-11-10 21:06:58.155974655 +0100
> +++ gcc/testsuite/g++.dg/cpp23/subscript9.C 2022-11-11 08:26:26.502445107 +0100
> @@ -0,0 +1,29 @@
> +// P2589R1
> +// { dg-do run { target c++23 } }
> +
> +extern "C" void abort ();
> +
> +struct S
> +{
> + S () {};
> + static int &operator[] () { return a[0]; }
> + static int &operator[] (int x) { return a[x]; }
> + static int &operator[] (int x, long y) { return a[x + y * 8]; }
> + static int a[64];
> +};
> +int S::a[64];
> +
> +int
> +main ()
> +{
> + S s;
> + for (int i = 0; i < 64; i++)
> + s.a[i] = 64 - i;
> + if (s[] != 64 || s[3] != 61 || s[4, 5] != 20)
> + abort ();
> + s[]++;
> + s[42]++;
> + ++s[3, 2];
> + if (s.a[0] != 65 || s.a[42] != 23 || s.a[19] != 46)
> + abort ();
> +}
> --- gcc/testsuite/g++.dg/cpp23/feat-cxx2b.C.jj 2022-10-06 08:56:28.785125656 +0200
> +++ gcc/testsuite/g++.dg/cpp23/feat-cxx2b.C 2022-11-10 22:31:49.187698955 +0100
> @@ -556,8 +556,8 @@
>
> #ifndef __cpp_multidimensional_subscript
> # error "__cpp_multidimensional_subscript"
> -#elif __cpp_multidimensional_subscript != 202110
> -# error "__cpp_multidimensional_subscript != 202110"
> +#elif __cpp_multidimensional_subscript != 202211
> +# error "__cpp_multidimensional_subscript != 202211"
> #endif
>
> #ifndef __cpp_named_character_escapes
> --- gcc/testsuite/g++.old-deja/g++.bugs/900210_10.C.jj 2020-01-14 20:02:47.021606269 +0100
> +++ gcc/testsuite/g++.old-deja/g++.bugs/900210_10.C 2022-11-11 01:41:13.840971578 +0100
> @@ -9,7 +9,7 @@
> // keywords: operator[], static function members
>
> struct struct0 {
> - static int operator[] (); /* { dg-error "" } */
> + static int operator[] (); /* { dg-error "" "" { target c++20_down } } */
> };
>
> int main () { return 0; }
>
> Jakub
>
next prev parent reply other threads:[~2022-11-14 23:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-11 7:40 Jakub Jelinek
2022-11-14 23:29 ` Jason Merrill [this message]
2022-11-15 12:28 ` [PATCH] c++: Fix up calls to static operator() or operator[] [PR107624] Jakub Jelinek
2022-11-15 21:49 ` Jason Merrill
2022-11-16 8:25 ` [PATCH] c++, v2: " Jakub Jelinek
2022-11-16 13:13 ` Jason Merrill
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