| Message ID | ZdcFafKIf8KkI7RP@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | c: Handle scoped attributes in __has*attribute and scoped attribute parsing changes in -std=c11 etc. modes [PR114007] | expand |
Hello, On Thu, 22 Feb 2024, Jakub Jelinek wrote: > So, the following patch adds a flag during preprocessing at the point > where we normally create CPP_SCOPE tokens out of 2 consecutive colons > on the first CPP_COLON to mark the consecutive case (as we are tight > on the bits, I've reused the PURE_ZERO flag, which is used just by the > C++ FE and only ever set (both C and C++) on CPP_NUMBER tokens, this > new flag has the same value and is only ever used on CPP_COLON tokens) Hmm, shouldn't you be able to use (nonexistence of) the PREV_WHITE flag on the second COLON token to see that it's indeed a '::' without intervening whitespace? Instead of setting a new flag on the first COLON token? I.e. something like this: if (c_parser_next_token_is (parser, CPP_SCOPE) - || (loose_scope_p - && c_parser_next_token_is (parser, CPP_COLON) && c_parser_peek_2nd_token (parser)->type == CPP_COLON)) + && !(c_parser_peek_2nd_token (parser)->flags & PREV_WHITE))) ? Ciao, Michael.
On Thu, Feb 22, 2024 at 03:59:31PM +0100, Michael Matz wrote: > Hello, > > On Thu, 22 Feb 2024, Jakub Jelinek wrote: > > > So, the following patch adds a flag during preprocessing at the point > > where we normally create CPP_SCOPE tokens out of 2 consecutive colons > > on the first CPP_COLON to mark the consecutive case (as we are tight > > on the bits, I've reused the PURE_ZERO flag, which is used just by the > > C++ FE and only ever set (both C and C++) on CPP_NUMBER tokens, this > > new flag has the same value and is only ever used on CPP_COLON tokens) > > Hmm, shouldn't you be able to use (nonexistence of) the PREV_WHITE flag on > the second COLON token to see that it's indeed a '::' without intervening > whitespace? Instead of setting a new flag on the first COLON token? > > I.e. something like this: > > if (c_parser_next_token_is (parser, CPP_SCOPE) > - || (loose_scope_p > - && c_parser_next_token_is (parser, CPP_COLON) > && c_parser_peek_2nd_token (parser)->type == CPP_COLON)) > + && !(c_parser_peek_2nd_token (parser)->flags & PREV_WHITE))) > > ? That doesn't seem to work. Compared to the posted patch it doesn't raise the 2 extra errors on gcc.dg/c23-attr-syntax-6.c #define JOIN2(A, B) A##B typedef int [[__extension__ gnu JOIN2(:,:) vector_size (4)]] b5; and that is just fine, that is error recovery after another error, but doesn't diagnose: #define BAR : typedef int [[__extension__ gnu BAR BAR vector_size (4)]] b8; nor #define JOIN(A, B) A/**/B typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] b10; (nor similar cases without __extension__). Maybe it is about whether there are CPP_PADDING tokens in between if PREV_WHITE is missing, but on c_parser_peek*_token we don't know if there were any. Sure, on the c_common_has_attribute side that could be done just by dropping the second loop. --- gcc/doc/extend.texi.jj 2024-02-22 10:10:18.907029080 +0100 +++ gcc/doc/extend.texi 2024-02-22 16:06:33.197555930 +0100 @@ -12626,10 +12626,7 @@ In C, writing: @end smallexample suppresses warnings about using @samp{[[]]} attributes in C versions -that predate C23@. Since the scope token @samp{::} is not a single -lexing token in earlier versions of C, this construct also allows two colons -to be used in place of @code{::}. GCC does not check whether the two -colons are immediately adjacent. +that predate C23@. @end itemize @code{__extension__} has no effect aside from this. --- gcc/c-family/c-lex.cc.jj 2024-02-22 10:09:48.408450163 +0100 +++ gcc/c-family/c-lex.cc 2024-02-22 16:09:50.822825035 +0100 @@ -357,7 +357,29 @@ c_common_has_attribute (cpp_reader *pfil do nxt_token = cpp_peek_token (pfile, idx++); while (nxt_token->type == CPP_PADDING); - if (nxt_token->type == CPP_SCOPE) + if (!c_dialect_cxx () + && flag_iso + && !flag_isoc23 + && nxt_token->type == CPP_COLON) + { + const cpp_token *prev_token = nxt_token; + do + nxt_token = cpp_peek_token (pfile, idx++); + while (nxt_token->type == CPP_PADDING); + if (nxt_token->type == CPP_COLON + && (nxt_token->flags & PREV_WHITE) == 0) + { + /* __has_attribute (vendor::attr) in -std=c17 etc. modes. + :: isn't CPP_SCOPE but 2 CPP_COLON tokens, where the + second one shouldn't have PREV_WHITE flag to distinguish + it from : :. */ + have_scope = true; + get_token_no_padding (pfile); // Eat first colon. + } + else + nxt_token = prev_token; + } + if (nxt_token->type == CPP_SCOPE || have_scope) { have_scope = true; get_token_no_padding (pfile); // Eat scope. --- gcc/c/c-parser.cc.jj 2024-02-22 10:09:48.467449349 +0100 +++ gcc/c/c-parser.cc 2024-02-22 16:11:05.320795586 +0100 @@ -5705,8 +5705,7 @@ c_parser_omp_sequence_args (c_parser *pa indicates whether this relaxation is in effect. */ static tree -c_parser_std_attribute (c_parser *parser, bool for_tm, - bool loose_scope_p = false) +c_parser_std_attribute (c_parser *parser, bool for_tm) { c_token *token = c_parser_peek_token (parser); tree ns, name, attribute; @@ -5720,9 +5719,10 @@ c_parser_std_attribute (c_parser *parser name = canonicalize_attr_name (token->value); c_parser_consume_token (parser); if (c_parser_next_token_is (parser, CPP_SCOPE) - || (loose_scope_p + || (!flag_isoc23 && c_parser_next_token_is (parser, CPP_COLON) - && c_parser_peek_2nd_token (parser)->type == CPP_COLON)) + && c_parser_peek_2nd_token (parser)->type == CPP_COLON + && (c_parser_peek_2nd_token (parser)->flags & PREV_WHITE) == 0)) { ns = name; if (c_parser_next_token_is (parser, CPP_COLON)) @@ -5841,8 +5841,7 @@ c_parser_std_attribute (c_parser *parser } static tree -c_parser_std_attribute_list (c_parser *parser, bool for_tm, - bool loose_scope_p = false) +c_parser_std_attribute_list (c_parser *parser, bool for_tm) { tree attributes = NULL_TREE; while (true) @@ -5855,7 +5854,7 @@ c_parser_std_attribute_list (c_parser *p c_parser_consume_token (parser); continue; } - tree attribute = c_parser_std_attribute (parser, for_tm, loose_scope_p); + tree attribute = c_parser_std_attribute (parser, for_tm); if (attribute != error_mark_node) { TREE_CHAIN (attribute) = attributes; @@ -5883,7 +5882,7 @@ c_parser_std_attribute_specifier (c_pars { auto ext = disable_extension_diagnostics (); c_parser_consume_token (parser); - attributes = c_parser_std_attribute_list (parser, for_tm, true); + attributes = c_parser_std_attribute_list (parser, for_tm); restore_extension_diagnostics (ext); } else --- gcc/testsuite/gcc.dg/c23-attr-syntax-6.c.jj 2024-02-22 10:09:48.912443204 +0100 +++ gcc/testsuite/gcc.dg/c23-attr-syntax-6.c 2024-02-22 16:06:33.227555515 +0100 @@ -9,19 +9,14 @@ typedef int [[__extension__ gnu::vector_size (4)]] g1; typedef int [[__extension__ gnu :: vector_size (4)]] g2; -typedef int [[__extension__ gnu : : vector_size (4)]] g3; -typedef int [[__extension__ gnu: :vector_size (4)]] g4; -typedef int [[__extension__ gnu FOO vector_size (4)]] g5; -typedef int [[__extension__ gnu BAR BAR vector_size (4)]] g6; -typedef int [[__extension__ gnu :/**/: vector_size (4)]] g7; -typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] g8; -typedef int [[__extension__ gnu :: vector_size (sizeof (void (*)(...)))]] g10; -typedef int [[__extension__]] g11; -typedef int [[__extension__,]] g12; -typedef int [[__extension__, ,,,, ,, ,]] g13; -[[__extension__ deprecated]] int g14 (); -[[__extension__ nodiscard]] int g15 (); -[[__extension__ noreturn]] void g16 (); +typedef int [[__extension__ gnu FOO vector_size (4)]] g3; +typedef int [[__extension__ gnu :: vector_size (sizeof (void (*)(...)))]] g4; +typedef int [[__extension__]] g5; +typedef int [[__extension__,]] g6; +typedef int [[__extension__, ,,,, ,, ,]] g7; +[[__extension__ deprecated]] int g8 (); +[[__extension__ nodiscard]] int g9 (); +[[__extension__ noreturn]] void g10 (); int cases (int x) @@ -51,12 +46,42 @@ typedef int [[__extension__ unknown_attr typedef int [[__extension__ gnu:vector_size(4)]] b4; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ typedef int [[__extension__ gnu JOIN2(:,:) vector_size (4)]] b5; /* { dg-error {pasting ":" and ":" does not give a valid preprocessing token} } */ -typedef int [[gnu::vector_size(4)]] b6; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {expected '\]' before ':'} "" { target *-*-* } .-1 } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-2 } */ +typedef int [[__extension__ gnu : : vector_size (4)]] b6; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu: :vector_size (4)]] b7; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu BAR BAR vector_size (4)]] b8; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu :/**/: vector_size (4)]] b9; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] b10; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[gnu::vector_size(4)]] b11; /* { dg-error {attributes before C23} } */ +typedef int [[gnu : : vector_size(4)]] b12; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu : vector_size(4)]] b13; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu: :vector_size (4)]] b14; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu BAR BAR vector_size (4)]] b15; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ -typedef int [[gnu : : vector_size(4)]] b7; /* { dg-error {expected '\]' before ':'} } */ +typedef int [[gnu :/**/: vector_size (4)]] b16; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ -typedef int [[gnu : vector_size(4)]] b8; /* { dg-error {expected '\]' before ':'} } */ +typedef int [[gnu JOIN(:,:) vector_size (4)]] b17; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu :: vector_size (4)]] b18; /* { dg-error {attributes before C23} } */ +typedef int [[gnu FOO vector_size (4)]] b19; /* { dg-error {attributes before C23} } */ +typedef int [[gnu :: vector_size (sizeof (void (*)(...)))]] b20; /* { dg-error {attributes before C23} } */ +/* { dg-error {requires a named argument before} "" { target *-*-* } .-1 } */ +typedef int [[gnu JOIN2(:,:) vector_size (4)]] b21; /* { dg-error {pasting ":" and ":" does not give a valid preprocessing token} } */ +/* { dg-error {expected '\]' before ':'} "" { target *-*-* } .-1 } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-2 } */ +/* { dg-error {attributes before C23} "" { target *-*-* } .-3 } */ --- gcc/testsuite/gcc.dg/c23-attr-syntax-7.c.jj 2024-02-22 10:09:48.957442583 +0100 +++ gcc/testsuite/gcc.dg/c23-attr-syntax-7.c 2024-02-22 16:06:33.227555515 +0100 @@ -9,19 +9,14 @@ typedef int [[__extension__ gnu::vector_size (4)]] g1; typedef int [[__extension__ gnu :: vector_size (4)]] g2; -typedef int [[__extension__ gnu : : vector_size (4)]] g3; -typedef int [[__extension__ gnu: :vector_size (4)]] g4; -typedef int [[__extension__ gnu FOO vector_size (4)]] g5; -typedef int [[__extension__ gnu BAR BAR vector_size (4)]] g6; -typedef int [[__extension__ gnu :/**/: vector_size (4)]] g7; -typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] g8; -typedef int [[__extension__ gnu :: vector_size (sizeof (void (*)(...)))]] g10; -typedef int [[__extension__]] g11; -typedef int [[__extension__,]] g12; -typedef int [[__extension__, ,,,, ,, ,]] g13; -[[__extension__ deprecated]] int g14 (); -[[__extension__ nodiscard]] int g15 (); -[[__extension__ noreturn]] void g16 (); +typedef int [[__extension__ gnu FOO vector_size (4)]] g3; +typedef int [[__extension__ gnu :: vector_size (sizeof (void (*)(...)))]] g4; +typedef int [[__extension__]] g5; +typedef int [[__extension__,]] g6; +typedef int [[__extension__, ,,,, ,, ,]] g7; +[[__extension__ deprecated]] int g8 (); +[[__extension__ nodiscard]] int g9 (); +[[__extension__ noreturn]] void g10 (); int cases (int x) @@ -51,10 +46,37 @@ typedef int [[__extension__ unknown_attr typedef int [[__extension__ gnu:vector_size(4)]] b4; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ typedef int [[__extension__ gnu JOIN2(:,:) vector_size (4)]] b5; -typedef int [[gnu::vector_size(4)]] b6; /* { dg-warning {attributes before C23} } */ -typedef int [[gnu : : vector_size(4)]] b7; /* { dg-error {expected '\]' before ':'} } */ +typedef int [[__extension__ gnu : : vector_size (4)]] b6; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu: :vector_size (4)]] b7; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu BAR BAR vector_size (4)]] b8; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu :/**/: vector_size (4)]] b9; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] b10; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[gnu::vector_size(4)]] b11; /* { dg-warning {attributes before C23} } */ +typedef int [[gnu : : vector_size(4)]] b12; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu : vector_size(4)]] b13; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu: :vector_size (4)]] b14; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu BAR BAR vector_size (4)]] b15; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu :/**/: vector_size (4)]] b16; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ -typedef int [[gnu : vector_size(4)]] b8; /* { dg-error {expected '\]' before ':'} } */ +typedef int [[gnu JOIN(:,:) vector_size (4)]] b17; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu :: vector_size (4)]] b18; /* { dg-warning {attributes before C23} } */ +typedef int [[gnu FOO vector_size (4)]] b19; /* { dg-warning {attributes before C23} } */ +typedef int [[gnu :: vector_size (sizeof (void (*)(...)))]] b20; /* { dg-warning {attributes before C23} } */ +/* { dg-warning {requires a named argument before} "" { target *-*-* } .-1 } */ +typedef int [[gnu JOIN2(:,:) vector_size (4)]] b21; /* { dg-warning {attributes before C23} } */ --- gcc/testsuite/gcc.dg/c23-attr-syntax-8.c.jj 2024-02-22 16:06:33.227555515 +0100 +++ gcc/testsuite/gcc.dg/c23-attr-syntax-8.c 2024-02-22 16:06:33.227555515 +0100 @@ -0,0 +1,12 @@ +/* PR c/114007 */ +/* { dg-do compile } */ +/* { dg-options "-std=c11" } */ + +#if __has_c_attribute (gnu::unused) +[[gnu::unused]] +#endif +int i; +#if __has_cpp_attribute (gnu::unused) +[[gnu::unused]] +#endif +int j; Jakub
Hi, On Thu, 22 Feb 2024, Jakub Jelinek wrote: > > Hmm, shouldn't you be able to use (nonexistence of) the PREV_WHITE flag on > > the second COLON token to see that it's indeed a '::' without intervening > > whitespace? Instead of setting a new flag on the first COLON token? > > > > I.e. something like this: > > > > if (c_parser_next_token_is (parser, CPP_SCOPE) > > - || (loose_scope_p > > - && c_parser_next_token_is (parser, CPP_COLON) > > && c_parser_peek_2nd_token (parser)->type == CPP_COLON)) > > + && !(c_parser_peek_2nd_token (parser)->flags & PREV_WHITE))) > > > > ? > > That doesn't seem to work. Too bad then. I had hoped it would make the code easier without changes to c-lex. Well, then ... was worth a try, I'll crouch back under my stone :) Ciao, Michael.
On Thu, 22 Feb 2024, Jakub Jelinek wrote: > Hi! > > We aren't able to parse __has_attribute (vendor::attr) (and __has_c_attribute > and __has_cpp_attribute) in strict C < C23 modes. While in -std=gnu* modes > or in -std=c23 there is CPP_SCOPE token, in -std=c* (except for -std=c23) > there are is just a pair of CPP_COLON tokens. > The c-lex.cc hunk adds support for that. > > That leads to a question if we should return 1 or 0 from > __has_attribute (gnu::unused) or not, because while > [[gnu::unused]] is parsed fine in -std=gnu*/-std=c23 modes (sure, with > pedwarn for < C23), we do not parse it at all in -std=c* (except for > -std=c23), we only parse [[__extension__ gnu::unused]] there. While > the __extension__ in there helps to avoid the pedwarn, I think it is > better to be consistent between GNU and strict C < C23 modes and > parse [[gnu::unused]] too; on the other side, I think parsing > [[__extension__ gnu : : unused]] is too weird and undesirable. > > So, the following patch adds a flag during preprocessing at the point > where we normally create CPP_SCOPE tokens out of 2 consecutive colons > on the first CPP_COLON to mark the consecutive case (as we are tight > on the bits, I've reused the PURE_ZERO flag, which is used just by the > C++ FE and only ever set (both C and C++) on CPP_NUMBER tokens, this > new flag has the same value and is only ever used on CPP_COLON tokens) > and instead of checking loose_scope_p argument (i.e. whether it is > [[__extension__ ...]] or not), it just parses CPP_SCOPE or CPP_COLON > with CLONE_SCOPE flag followed by another CPP_COLON the same. > The latter will never appear in >= C23 or -std=gnu* modes, though > guarding its use say with flag_iso && !flag_isoc23 && doesn't really > work because the __extension__ case temporarily clears flag_iso flag. This patch (the one using COLON_SCOPE, *not* the one using PREV_WHITE) is OK. PREV_WHITE is about whether there is whitespace between the tokens in the macro expansion, for the purposes of stringization - I don't think it's appropriate to use here. For example, given #define COLON() : then [[gnu COLON()COLON() unused]] int x; should preferably not be valid; stringizing the results of expanding COLON()COLON() will produce "::" (PREV_WHITE not set), but that wouldn't be a valid attribute in C23 and I don't think anyone could reasonably expect it to be valid with previous standard versions.
On Thu, Feb 22, 2024 at 05:49:12PM +0000, Joseph Myers wrote: > This patch (the one using COLON_SCOPE, *not* the one using PREV_WHITE) is > OK. > > PREV_WHITE is about whether there is whitespace between the tokens in the > macro expansion, for the purposes of stringization - I don't think it's > appropriate to use here. For example, given > > #define COLON() : > > then > > [[gnu COLON()COLON() unused]] int x; > > should preferably not be valid; stringizing the results of expanding > COLON()COLON() will produce "::" (PREV_WHITE not set), but that wouldn't > be a valid attribute in C23 and I don't think anyone could reasonably > expect it to be valid with previous standard versions. It is not valid in either version of the patch, with any of -std=c11, -std=gnu11 or -std=c23 with both compilers I get the same /tmp/test.c:2:1: warning: ‘gnu’ attribute ignored [-Wattributes] 2 | [[gnu COLON()COLON() unused]] int x; | ^ /tmp/test.c:2:6: error: expected ‘]’ before ‘:’ token 2 | [[gnu COLON()COLON() unused]] int x; | ^ | ] message all the time. But sure, if you prefer the COLON_SCOPE version of the patch, I can commit that. There is no PREV_WHITE in the preprocessor, there is CPP_PADDING token in between the CPP_COLONs though and that translates into PREV_WHITE on the second CPP_COLON in the FE token. When trying to verify it, I've noticed one typo in the PREV_WHITE patch: @@ -73,7 +73,7 @@ gcc/testsuite/ switch (type) { case CPP_PADDING: -+ add_flags |= CPP_PADDING; ++ add_flags |= PREV_WHITE; goto retry; case CPP_NAME: but it doesn't change anything on the outcome of those tests nor your testcase above nor the C++ -std=c++98 -fpermissive test. CPP_PADDING is 85 and PREV_WHITE 1, so it was setting PREV_WHITE too (just 3 other flags too). Jakub
On Thu, 22 Feb 2024, Jakub Jelinek wrote: > But sure, if you prefer the COLON_SCOPE version of the patch, I can commit > that. There is no PREV_WHITE in the preprocessor, there is Yes, I prefer the COLON_SCOPE version.
--- gcc/doc/extend.texi.jj 2024-02-21 10:46:55.746515061 +0100 +++ gcc/doc/extend.texi 2024-02-21 17:03:22.137717754 +0100 @@ -12626,10 +12626,7 @@ In C, writing: @end smallexample suppresses warnings about using @samp{[[]]} attributes in C versions -that predate C23@. Since the scope token @samp{::} is not a single -lexing token in earlier versions of C, this construct also allows two colons -to be used in place of @code{::}. GCC does not check whether the two -colons are immediately adjacent. +that predate C23@. @end itemize @code{__extension__} has no effect aside from this. --- gcc/c-family/c-lex.cc.jj 2024-01-03 12:07:02.171734141 +0100 +++ gcc/c-family/c-lex.cc 2024-02-21 18:07:37.615640395 +0100 @@ -357,7 +357,24 @@ c_common_has_attribute (cpp_reader *pfil do nxt_token = cpp_peek_token (pfile, idx++); while (nxt_token->type == CPP_PADDING); - if (nxt_token->type == CPP_SCOPE) + if (!c_dialect_cxx () + && nxt_token->type == CPP_COLON + && (nxt_token->flags & COLON_SCOPE) != 0) + { + do + nxt_token = cpp_peek_token (pfile, idx++); + while (nxt_token->type == CPP_PADDING); + if (nxt_token->type == CPP_COLON) + { + /* __has_attribute (vendor::attr) in -std=c17 etc. modes. + :: isn't CPP_SCOPE but 2 CPP_COLON tokens, where the + first one should have COLON_SCOPE flag to distinguish + it from : :. */ + have_scope = true; + get_token_no_padding (pfile); // Eat first colon. + } + } + if (nxt_token->type == CPP_SCOPE || have_scope) { have_scope = true; get_token_no_padding (pfile); // Eat scope. --- gcc/c/c-parser.cc.jj 2024-02-14 14:26:19.599812963 +0100 +++ gcc/c/c-parser.cc 2024-02-21 18:07:20.583874512 +0100 @@ -5705,8 +5705,7 @@ c_parser_omp_sequence_args (c_parser *pa indicates whether this relaxation is in effect. */ static tree -c_parser_std_attribute (c_parser *parser, bool for_tm, - bool loose_scope_p = false) +c_parser_std_attribute (c_parser *parser, bool for_tm) { c_token *token = c_parser_peek_token (parser); tree ns, name, attribute; @@ -5720,8 +5719,8 @@ c_parser_std_attribute (c_parser *parser name = canonicalize_attr_name (token->value); c_parser_consume_token (parser); if (c_parser_next_token_is (parser, CPP_SCOPE) - || (loose_scope_p - && c_parser_next_token_is (parser, CPP_COLON) + || (c_parser_next_token_is (parser, CPP_COLON) + && (c_parser_peek_token (parser)->flags & COLON_SCOPE) != 0 && c_parser_peek_2nd_token (parser)->type == CPP_COLON)) { ns = name; @@ -5841,8 +5840,7 @@ c_parser_std_attribute (c_parser *parser } static tree -c_parser_std_attribute_list (c_parser *parser, bool for_tm, - bool loose_scope_p = false) +c_parser_std_attribute_list (c_parser *parser, bool for_tm) { tree attributes = NULL_TREE; while (true) @@ -5855,7 +5853,7 @@ c_parser_std_attribute_list (c_parser *p c_parser_consume_token (parser); continue; } - tree attribute = c_parser_std_attribute (parser, for_tm, loose_scope_p); + tree attribute = c_parser_std_attribute (parser, for_tm); if (attribute != error_mark_node) { TREE_CHAIN (attribute) = attributes; @@ -5883,7 +5881,7 @@ c_parser_std_attribute_specifier (c_pars { auto ext = disable_extension_diagnostics (); c_parser_consume_token (parser); - attributes = c_parser_std_attribute_list (parser, for_tm, true); + attributes = c_parser_std_attribute_list (parser, for_tm); restore_extension_diagnostics (ext); } else --- gcc/testsuite/gcc.dg/c23-attr-syntax-6.c.jj 2023-11-09 09:04:19.499530894 +0100 +++ gcc/testsuite/gcc.dg/c23-attr-syntax-6.c 2024-02-21 19:16:48.904662570 +0100 @@ -9,19 +9,14 @@ typedef int [[__extension__ gnu::vector_size (4)]] g1; typedef int [[__extension__ gnu :: vector_size (4)]] g2; -typedef int [[__extension__ gnu : : vector_size (4)]] g3; -typedef int [[__extension__ gnu: :vector_size (4)]] g4; -typedef int [[__extension__ gnu FOO vector_size (4)]] g5; -typedef int [[__extension__ gnu BAR BAR vector_size (4)]] g6; -typedef int [[__extension__ gnu :/**/: vector_size (4)]] g7; -typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] g8; -typedef int [[__extension__ gnu :: vector_size (sizeof (void (*)(...)))]] g10; -typedef int [[__extension__]] g11; -typedef int [[__extension__,]] g12; -typedef int [[__extension__, ,,,, ,, ,]] g13; -[[__extension__ deprecated]] int g14 (); -[[__extension__ nodiscard]] int g15 (); -[[__extension__ noreturn]] void g16 (); +typedef int [[__extension__ gnu FOO vector_size (4)]] g3; +typedef int [[__extension__ gnu :: vector_size (sizeof (void (*)(...)))]] g4; +typedef int [[__extension__]] g5; +typedef int [[__extension__,]] g6; +typedef int [[__extension__, ,,,, ,, ,]] g7; +[[__extension__ deprecated]] int g8 (); +[[__extension__ nodiscard]] int g9 (); +[[__extension__ noreturn]] void g10 (); int cases (int x) @@ -51,12 +46,42 @@ typedef int [[__extension__ unknown_attr typedef int [[__extension__ gnu:vector_size(4)]] b4; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ typedef int [[__extension__ gnu JOIN2(:,:) vector_size (4)]] b5; /* { dg-error {pasting ":" and ":" does not give a valid preprocessing token} } */ -typedef int [[gnu::vector_size(4)]] b6; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {expected '\]' before ':'} "" { target *-*-* } .-1 } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-2 } */ +typedef int [[__extension__ gnu : : vector_size (4)]] b6; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu: :vector_size (4)]] b7; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu BAR BAR vector_size (4)]] b8; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu :/**/: vector_size (4)]] b9; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] b10; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[gnu::vector_size(4)]] b11; /* { dg-error {attributes before C23} } */ +typedef int [[gnu : : vector_size(4)]] b12; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu : vector_size(4)]] b13; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu: :vector_size (4)]] b14; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu BAR BAR vector_size (4)]] b15; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ -typedef int [[gnu : : vector_size(4)]] b7; /* { dg-error {expected '\]' before ':'} } */ +typedef int [[gnu :/**/: vector_size (4)]] b16; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ -typedef int [[gnu : vector_size(4)]] b8; /* { dg-error {expected '\]' before ':'} } */ +typedef int [[gnu JOIN(:,:) vector_size (4)]] b17; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-error {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu :: vector_size (4)]] b18; /* { dg-error {attributes before C23} } */ +typedef int [[gnu FOO vector_size (4)]] b19; /* { dg-error {attributes before C23} } */ +typedef int [[gnu :: vector_size (sizeof (void (*)(...)))]] b20; /* { dg-error {attributes before C23} } */ +/* { dg-error {requires a named argument before} "" { target *-*-* } .-1 } */ +typedef int [[gnu JOIN2(:,:) vector_size (4)]] b21; /* { dg-error {pasting ":" and ":" does not give a valid preprocessing token} } */ +/* { dg-error {expected '\]' before ':'} "" { target *-*-* } .-1 } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-2 } */ +/* { dg-error {attributes before C23} "" { target *-*-* } .-3 } */ --- gcc/testsuite/gcc.dg/c23-attr-syntax-7.c.jj 2023-11-09 09:04:19.499530894 +0100 +++ gcc/testsuite/gcc.dg/c23-attr-syntax-7.c 2024-02-21 19:17:19.193247405 +0100 @@ -9,19 +9,14 @@ typedef int [[__extension__ gnu::vector_size (4)]] g1; typedef int [[__extension__ gnu :: vector_size (4)]] g2; -typedef int [[__extension__ gnu : : vector_size (4)]] g3; -typedef int [[__extension__ gnu: :vector_size (4)]] g4; -typedef int [[__extension__ gnu FOO vector_size (4)]] g5; -typedef int [[__extension__ gnu BAR BAR vector_size (4)]] g6; -typedef int [[__extension__ gnu :/**/: vector_size (4)]] g7; -typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] g8; -typedef int [[__extension__ gnu :: vector_size (sizeof (void (*)(...)))]] g10; -typedef int [[__extension__]] g11; -typedef int [[__extension__,]] g12; -typedef int [[__extension__, ,,,, ,, ,]] g13; -[[__extension__ deprecated]] int g14 (); -[[__extension__ nodiscard]] int g15 (); -[[__extension__ noreturn]] void g16 (); +typedef int [[__extension__ gnu FOO vector_size (4)]] g3; +typedef int [[__extension__ gnu :: vector_size (sizeof (void (*)(...)))]] g4; +typedef int [[__extension__]] g5; +typedef int [[__extension__,]] g6; +typedef int [[__extension__, ,,,, ,, ,]] g7; +[[__extension__ deprecated]] int g8 (); +[[__extension__ nodiscard]] int g9 (); +[[__extension__ noreturn]] void g10 (); int cases (int x) @@ -51,10 +46,37 @@ typedef int [[__extension__ unknown_attr typedef int [[__extension__ gnu:vector_size(4)]] b4; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ typedef int [[__extension__ gnu JOIN2(:,:) vector_size (4)]] b5; -typedef int [[gnu::vector_size(4)]] b6; /* { dg-warning {attributes before C23} } */ -typedef int [[gnu : : vector_size(4)]] b7; /* { dg-error {expected '\]' before ':'} } */ +typedef int [[__extension__ gnu : : vector_size (4)]] b6; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu: :vector_size (4)]] b7; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu BAR BAR vector_size (4)]] b8; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu :/**/: vector_size (4)]] b9; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] b10; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +typedef int [[gnu::vector_size(4)]] b11; /* { dg-warning {attributes before C23} } */ +typedef int [[gnu : : vector_size(4)]] b12; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu : vector_size(4)]] b13; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu: :vector_size (4)]] b14; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu BAR BAR vector_size (4)]] b15; /* { dg-error {expected '\]' before ':'} } */ +/* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ +/* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu :/**/: vector_size (4)]] b16; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ -typedef int [[gnu : vector_size(4)]] b8; /* { dg-error {expected '\]' before ':'} } */ +typedef int [[gnu JOIN(:,:) vector_size (4)]] b17; /* { dg-error {expected '\]' before ':'} } */ /* { dg-error {'gnu' attribute ignored} "" { target *-*-* } .-1 } */ /* { dg-warning {attributes before C23} "" { target *-*-* } .-2 } */ +typedef int [[gnu :: vector_size (4)]] b18; /* { dg-warning {attributes before C23} } */ +typedef int [[gnu FOO vector_size (4)]] b19; /* { dg-warning {attributes before C23} } */ +typedef int [[gnu :: vector_size (sizeof (void (*)(...)))]] b20; /* { dg-warning {attributes before C23} } */ +/* { dg-warning {requires a named argument before} "" { target *-*-* } .-1 } */ +typedef int [[gnu JOIN2(:,:) vector_size (4)]] b21; /* { dg-warning {attributes before C23} } */ --- gcc/testsuite/gcc.dg/c23-attr-syntax-8.c.jj 2024-02-21 17:12:06.949467337 +0100 +++ gcc/testsuite/gcc.dg/c23-attr-syntax-8.c 2024-02-21 17:07:37.412189117 +0100 @@ -0,0 +1,12 @@ +/* PR c/114007 */ +/* { dg-do compile } */ +/* { dg-options "-std=c11" } */ + +#if __has_c_attribute (gnu::unused) +[[gnu::unused]] +#endif +int i; +#if __has_cpp_attribute (gnu::unused) +[[gnu::unused]] +#endif +int j; --- libcpp/include/cpplib.h.jj 2024-01-05 08:35:13.720827001 +0100 +++ libcpp/include/cpplib.h 2024-02-21 16:45:17.134709568 +0100 @@ -200,6 +200,7 @@ struct GTY(()) cpp_string { #define DECIMAL_INT (1 << 6) /* Decimal integer, set in c-lex.cc. */ #define PURE_ZERO (1 << 7) /* Single 0 digit, used by the C++ frontend, set in c-lex.cc. */ +#define COLON_SCOPE PURE_ZERO /* Adjacent colons in C < 23. */ #define SP_DIGRAPH (1 << 8) /* # or ## token was a digraph. */ #define SP_PREV_WHITE (1 << 9) /* If whitespace before a ## operator, or before this token --- libcpp/lex.cc.jj 2024-01-03 12:07:27.589378046 +0100 +++ libcpp/lex.cc 2024-02-21 16:38:38.719164770 +0100 @@ -4235,8 +4235,13 @@ _cpp_lex_direct (cpp_reader *pfile) case ':': result->type = CPP_COLON; - if (*buffer->cur == ':' && CPP_OPTION (pfile, scope)) - buffer->cur++, result->type = CPP_SCOPE; + if (*buffer->cur == ':') + { + if (CPP_OPTION (pfile, scope)) + buffer->cur++, result->type = CPP_SCOPE; + else + result->flags |= COLON_SCOPE; + } else if (*buffer->cur == '>' && CPP_OPTION (pfile, digraphs)) { buffer->cur++;