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
