diff mbox series

c, v2: Handle scoped attributes in __has*attribute and scoped attribute parsing changes in -std=c11 etc. modes [PR114007]

Message ID ZddxU28IKjG+ayx3@tucnak
State New
Headers show
Series c, v2: Handle scoped attributes in __has*attribute and scoped attribute parsing changes in -std=c11 etc. modes [PR114007] | expand

Commit Message

Jakub Jelinek Feb. 22, 2024, 4:07 p.m. UTC 
On Thu, Feb 22, 2024 at 04:35:22PM +0100, Michael Matz wrote:
> 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
> :)

Actually, I could make it work with two simple add_flags |= PREV_WHITE;
in c_lex_with_flags.  PREV_WHITE in FE tokens is only checked in this new
spot in [[]] C parsing and in
  /* If we find the sequence `[:' after a template-name, it's probably
     a digraph-typo for `< ::'. Substitute the tokens and check if we can
     parse correctly the argument list.  */
  if (((next_token = cp_lexer_peek_token (parser->lexer))->type
       == CPP_OPEN_SQUARE)
      && next_token->flags & DIGRAPH
      && ((next_token_2 = cp_lexer_peek_nth_token (parser->lexer, 2))->type
          == CPP_COLON)
      && !(next_token_2->flags & PREV_WHITE))
    {
      cp_parser_parse_tentatively (parser);
      /* Change `:' into `::'.  */
      next_token_2->type = CPP_SCOPE;
      /* Consume the first token (CPP_OPEN_SQUARE - which we pretend it is
         CPP_LESS.  */
      cp_lexer_consume_token (parser->lexer);
in C++ FE and the same workaround in another spot.  But seems -std=c++98
-fpermissive on
struct S{};
template <typename T> struct U{};
U<::S> u;
U<:/**/:S> v;
#define FOO <:
#define BAR
U FOO BAR S> w;
actually doesn't change, u is accepted with -fpermissive and v/w are rejected
without/with the patch, apparently it already has PREV_WHITE flag set in
those cases for some reason.

2024-02-22  Jakub Jelinek  <jakub@redhat.com>

	PR c/114007
gcc/
	* doc/extend.texi: (__extension__): Remove comments about scope
	tokens vs. two colons.
gcc/c-family/
	* c-lex.cc (c_common_has_attribute): Parse 2 CPP_COLONs with
	the second one without PREV_WHITE flag the same as CPP_SCOPE.
	(c_lex_with_flags): For CPP_PADDING or CPP_COMMENT, or PREV_WHITE
	into add_flags.
gcc/c/
	* c-parser.cc (c_parser_std_attribute): Remove loose_scope_p argument.
	Instead of checking it, parse 2 CPP_COLONs with the second one without
	PREV_WHITE flag the same as CPP_SCOPE.
	(c_parser_std_attribute_list): Remove loose_scope_p argument, don't
	pass it to c_parser_std_attribute.
	(c_parser_std_attribute_specifier): Adjust c_parser_std_attribute_list
	caller.
gcc/testsuite/
	* gcc.dg/c23-attr-syntax-6.c: Adjust testcase for :: being valid
	even in -std=c11 even without __extension__ and : : etc. not being
	valid anymore even with __extension__.
	* gcc.dg/c23-attr-syntax-7.c: Likewise.
	* gcc.dg/c23-attr-syntax-8.c: New test.



	Jakub
diff mbox series

Patch

--- 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 16:40:59.003000082 +0100
@@ -357,7 +357,27 @@  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;
+	  nxt_token = cpp_peek_token (pfile, idx);
+	  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.
@@ -556,6 +576,7 @@  c_lex_with_flags (tree *value, location_
   switch (type)
     {
     case CPP_PADDING:
+      add_flags |= CPP_PADDING;
       goto retry;
 
     case CPP_NAME:
@@ -769,6 +790,7 @@  c_lex_with_flags (tree *value, location_
        when it is a FALLTHROUGH comment, in that case set
        PREV_FALLTHROUGH flag on the next non-comment token.  */
     case CPP_COMMENT:
+      add_flags |= PREV_WHITE;
       if (tok->flags & PREV_FALLTHROUGH)
 	{
 	  do
--- 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;