* [PATCH] c++: Disallow this specifier except for parameter declarations [PR113788]
@ 2024-02-06 20:37 Jakub Jelinek
2024-02-06 20:45 ` Marek Polacek
0 siblings, 1 reply; 3+ messages in thread
From: Jakub Jelinek @ 2024-02-06 20:37 UTC (permalink / raw)
To: Jason Merrill; +Cc: gcc-patches
Hi!
The deducing this patchset added parsing of this specifier to
cp_parser_decl_specifier_seq unconditionally, but in the C++ grammar
this[opt] only appears in the parameter-declaration non-terminal, so
rather than checking in all the callers of cp_parser_decl_specifier_seq
except for cp_parser_parameter_declaration that this specifier didn't
appear I think it is far easier and closer to what the standard says
to only parse this specifier when called from
cp_parser_parameter_declaration.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2024-02-06 Jakub Jelinek <jakub@redhat.com>
PR c++/113788
* parser.cc (CP_PARSER_FLAGS_PARAMETER): New enumerator.
(cp_parser_decl_specifier_seq): Parse RID_THIS only if
CP_PARSER_FLAGS_PARAMETER is set in flags.
(cp_parser_parameter_declaration): Or in CP_PARSER_FLAGS_PARAMETER
when calling cp_parser_decl_specifier_seq.
* g++.dg/parse/pr113788.C: New test.
--- gcc/cp/parser.cc.jj 2024-01-17 10:34:45.337660930 +0100
+++ gcc/cp/parser.cc 2024-02-06 18:31:35.587193903 +0100
@@ -2088,7 +2088,9 @@ enum
/* When parsing of the noexcept-specifier should be delayed. */
CP_PARSER_FLAGS_DELAY_NOEXCEPT = 0x40,
/* When parsing a consteval declarator. */
- CP_PARSER_FLAGS_CONSTEVAL = 0x80
+ CP_PARSER_FLAGS_CONSTEVAL = 0x80,
+ /* When parsing a parameter declaration. */
+ CP_PARSER_FLAGS_PARAMETER = 0x100
};
/* This type is used for parameters and variables which hold
@@ -16342,7 +16344,7 @@ cp_parser_decl_specifier_seq (cp_parser*
/* Special case for "this" specifier, indicating a parm is an xobj parm.
The "this" specifier must be the first specifier in the declaration,
after any attributes. */
- if (token->keyword == RID_THIS)
+ if (token->keyword == RID_THIS && (flags & CP_PARSER_FLAGS_PARAMETER))
{
cp_lexer_consume_token (parser->lexer);
if (token != first_specifier)
@@ -25607,7 +25609,7 @@ cp_parser_parameter_declaration (cp_pars
/* Parse the declaration-specifiers. */
cp_token *decl_spec_token_start = cp_lexer_peek_token (parser->lexer);
cp_parser_decl_specifier_seq (parser,
- flags,
+ flags | CP_PARSER_FLAGS_PARAMETER,
&decl_specifiers,
&declares_class_or_enum);
--- gcc/testsuite/g++.dg/parse/pr113788.C.jj 2024-02-06 18:40:29.553791028 +0100
+++ gcc/testsuite/g++.dg/parse/pr113788.C 2024-02-06 18:41:23.326045703 +0100
@@ -0,0 +1,20 @@
+// PR c++/113788
+// { dg-do compile { target c++11 } }
+
+struct S { int a, b; };
+struct U {
+ void foo () { this int g = 1; } // { dg-error "expected ';' before 'int'" }
+};
+this auto h = 1; // { dg-error "expected unqualified-id before 'this'" }
+
+int
+main ()
+{
+ S s = { 1, 2 };
+ short t[3] = { 3, 4, 5 };
+ this auto &[a, b] = s; // { dg-error "invalid use of 'this' in non-member function" }
+ this auto &[c, d, e] = t; // { dg-error "invalid use of 'this' in non-member function" }
+ this int f = 1; // { dg-error "invalid use of 'this' in non-member function" }
+ for (this auto &i : t) // { dg-error "invalid use of 'this' in non-member function" }
+ ; // { dg-error "expected" }
+} // { dg-error "expected" }
Jakub
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] c++: Disallow this specifier except for parameter declarations [PR113788]
2024-02-06 20:37 [PATCH] c++: Disallow this specifier except for parameter declarations [PR113788] Jakub Jelinek
@ 2024-02-06 20:45 ` Marek Polacek
2024-02-06 21:32 ` Jason Merrill
0 siblings, 1 reply; 3+ messages in thread
From: Marek Polacek @ 2024-02-06 20:45 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: Jason Merrill, gcc-patches
On Tue, Feb 06, 2024 at 09:37:44PM +0100, Jakub Jelinek wrote:
> Hi!
>
> The deducing this patchset added parsing of this specifier to
> cp_parser_decl_specifier_seq unconditionally, but in the C++ grammar
> this[opt] only appears in the parameter-declaration non-terminal, so
> rather than checking in all the callers of cp_parser_decl_specifier_seq
> except for cp_parser_parameter_declaration that this specifier didn't
> appear I think it is far easier and closer to what the standard says
> to only parse this specifier when called from
> cp_parser_parameter_declaration.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
FWIW, the patch looks good to me.
> 2024-02-06 Jakub Jelinek <jakub@redhat.com>
>
> PR c++/113788
> * parser.cc (CP_PARSER_FLAGS_PARAMETER): New enumerator.
> (cp_parser_decl_specifier_seq): Parse RID_THIS only if
> CP_PARSER_FLAGS_PARAMETER is set in flags.
> (cp_parser_parameter_declaration): Or in CP_PARSER_FLAGS_PARAMETER
> when calling cp_parser_decl_specifier_seq.
>
> * g++.dg/parse/pr113788.C: New test.
>
> --- gcc/cp/parser.cc.jj 2024-01-17 10:34:45.337660930 +0100
> +++ gcc/cp/parser.cc 2024-02-06 18:31:35.587193903 +0100
> @@ -2088,7 +2088,9 @@ enum
> /* When parsing of the noexcept-specifier should be delayed. */
> CP_PARSER_FLAGS_DELAY_NOEXCEPT = 0x40,
> /* When parsing a consteval declarator. */
> - CP_PARSER_FLAGS_CONSTEVAL = 0x80
> + CP_PARSER_FLAGS_CONSTEVAL = 0x80,
> + /* When parsing a parameter declaration. */
> + CP_PARSER_FLAGS_PARAMETER = 0x100
> };
>
> /* This type is used for parameters and variables which hold
> @@ -16342,7 +16344,7 @@ cp_parser_decl_specifier_seq (cp_parser*
> /* Special case for "this" specifier, indicating a parm is an xobj parm.
> The "this" specifier must be the first specifier in the declaration,
> after any attributes. */
> - if (token->keyword == RID_THIS)
> + if (token->keyword == RID_THIS && (flags & CP_PARSER_FLAGS_PARAMETER))
> {
> cp_lexer_consume_token (parser->lexer);
> if (token != first_specifier)
> @@ -25607,7 +25609,7 @@ cp_parser_parameter_declaration (cp_pars
> /* Parse the declaration-specifiers. */
> cp_token *decl_spec_token_start = cp_lexer_peek_token (parser->lexer);
> cp_parser_decl_specifier_seq (parser,
> - flags,
> + flags | CP_PARSER_FLAGS_PARAMETER,
> &decl_specifiers,
> &declares_class_or_enum);
>
> --- gcc/testsuite/g++.dg/parse/pr113788.C.jj 2024-02-06 18:40:29.553791028 +0100
> +++ gcc/testsuite/g++.dg/parse/pr113788.C 2024-02-06 18:41:23.326045703 +0100
> @@ -0,0 +1,20 @@
> +// PR c++/113788
> +// { dg-do compile { target c++11 } }
> +
> +struct S { int a, b; };
> +struct U {
> + void foo () { this int g = 1; } // { dg-error "expected ';' before 'int'" }
> +};
> +this auto h = 1; // { dg-error "expected unqualified-id before 'this'" }
> +
> +int
> +main ()
> +{
> + S s = { 1, 2 };
> + short t[3] = { 3, 4, 5 };
> + this auto &[a, b] = s; // { dg-error "invalid use of 'this' in non-member function" }
> + this auto &[c, d, e] = t; // { dg-error "invalid use of 'this' in non-member function" }
> + this int f = 1; // { dg-error "invalid use of 'this' in non-member function" }
> + for (this auto &i : t) // { dg-error "invalid use of 'this' in non-member function" }
> + ; // { dg-error "expected" }
> +} // { dg-error "expected" }
>
> Jakub
>
Marek
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] c++: Disallow this specifier except for parameter declarations [PR113788]
2024-02-06 20:45 ` Marek Polacek
@ 2024-02-06 21:32 ` Jason Merrill
0 siblings, 0 replies; 3+ messages in thread
From: Jason Merrill @ 2024-02-06 21:32 UTC (permalink / raw)
To: Marek Polacek, Jakub Jelinek; +Cc: gcc-patches
On 2/6/24 15:45, Marek Polacek wrote:
> On Tue, Feb 06, 2024 at 09:37:44PM +0100, Jakub Jelinek wrote:
>> Hi!
>>
>> The deducing this patchset added parsing of this specifier to
>> cp_parser_decl_specifier_seq unconditionally, but in the C++ grammar
>> this[opt] only appears in the parameter-declaration non-terminal, so
>> rather than checking in all the callers of cp_parser_decl_specifier_seq
>> except for cp_parser_parameter_declaration that this specifier didn't
>> appear I think it is far easier and closer to what the standard says
>> to only parse this specifier when called from
>> cp_parser_parameter_declaration.
>>
>> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> FWIW, the patch looks good to me.
Agreed, OK.
Jason
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-02-06 20:37 [PATCH] c++: Disallow this specifier except for parameter declarations [PR113788] Jakub Jelinek
2024-02-06 20:45 ` Marek Polacek
2024-02-06 21:32 ` Jason Merrill
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