asm qualifiers (PR55681)

PR55681 observes that currently only one qualifier is allowed for
inline asm, so that e.g. "volatile asm" is allowed, "const asm" is also
okay (with a warning), but "const volatile asm" gives an error.  Also
"goto" has to be last.

This patch changes things so that only "asm-qualifiers" are allowed,
that is "volatile" and "goto", in any combination, in any order, but
without repetitions.


	PR inline-asm/55681
	* doc/extend.texi (Basic Asm): Update grammar.
	(Extended Asm): Update grammar.

gcc/c/
	PR inline-asm/55681
	* c-parser.c (c_parser_asm_statement): Update grammar.  Allow any
	combination of volatile and goto, in any order, without repetitions.

gcc/cp/
	PR inline-asm/55681
	* parser.c (cp_parser_asm_definition): Update grammar.  Allow any
	combination of volatile and goto, in any order, without repetitions.

gcc/testsuite/
	PR inline-asm/55681
	* gcc.dg/asm-qual-1.c: Test that "const" and "restrict" are refused.
	* gcc.dg/asm-qual-2.c: New test, test that asm-qualifiers are allowed
	in any order, but that duplicates are not allowed.

From-SVN: r266859

1 files changed, 51 insertions, 26 deletions

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index ac19cb4..ac953d0 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -19590,22 +19590,34 @@ cp_parser_using_directive (cp_parser* parser)
 
 /* Parse an asm-definition.
 
+  asm-qualifier:
+    volatile
+    goto
+
+  asm-qualifier-list:
+    asm-qualifier
+    asm-qualifier-list asm-qualifier
+
    asm-definition:
      asm ( string-literal ) ;
 
    GNU Extension:
 
    asm-definition:
-     asm volatile [opt] ( string-literal ) ;
-     asm volatile [opt] ( string-literal : asm-operand-list [opt] ) ;
-     asm volatile [opt] ( string-literal : asm-operand-list [opt]
-			  : asm-operand-list [opt] ) ;
-     asm volatile [opt] ( string-literal : asm-operand-list [opt]
-			  : asm-operand-list [opt]
+     asm asm-qualifier-list [opt] ( string-literal ) ;
+     asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt] ) ;
+     asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt]
+				    : asm-operand-list [opt] ) ;
+     asm asm-qualifier-list [opt] ( string-literal : asm-operand-list [opt]
+				    : asm-operand-list [opt]
 			  : asm-clobber-list [opt] ) ;
-     asm volatile [opt] goto ( string-literal : : asm-operand-list [opt]
-			       : asm-clobber-list [opt]
-			       : asm-goto-list ) ;  */
+     asm asm-qualifier-list [opt] ( string-literal : : asm-operand-list [opt]
+				    : asm-clobber-list [opt]
+				    : asm-goto-list ) ;
+
+  The form with asm-goto-list is valid if and only if the asm-qualifier-list
+  contains goto, and is the only allowed form in that case.  No duplicates are
+  allowed in an asm-qualifier-list.  */
 
 static void
 cp_parser_asm_definition (cp_parser* parser)
@@ -19634,23 +19646,36 @@ cp_parser_asm_definition (cp_parser* parser)
     }
 
   /* See if the next token is `volatile'.  */
-  if (cp_parser_allow_gnu_extensions_p (parser)
-      && cp_lexer_next_token_is_keyword (parser->lexer, RID_VOLATILE))
-    {
-      /* Remember that we saw the `volatile' keyword.  */
-      volatile_p = true;
-      /* Consume the token.  */
-      cp_lexer_consume_token (parser->lexer);
-    }
-  if (cp_parser_allow_gnu_extensions_p (parser)
-      && parser->in_function_body
-      && cp_lexer_next_token_is_keyword (parser->lexer, RID_GOTO))
-    {
-      /* Remember that we saw the `goto' keyword.  */
-      goto_p = true;
-      /* Consume the token.  */
-      cp_lexer_consume_token (parser->lexer);
-    }
+  if (cp_parser_allow_gnu_extensions_p (parser))
+    for (bool done = false; !done ; )
+      switch (cp_lexer_peek_token (parser->lexer)->keyword)
+	{
+	case RID_VOLATILE:
+	  if (!volatile_p)
+	    {
+	      /* Remember that we saw the `volatile' keyword.  */
+	      volatile_p = true;
+	      /* Consume the token.  */
+	      cp_lexer_consume_token (parser->lexer);
+	    }
+	  else
+	    done = true;
+	  break;
+	case RID_GOTO:
+	  if (!goto_p && parser->in_function_body)
+	    {
+	      /* Remember that we saw the `goto' keyword.  */
+	      goto_p = true;
+	      /* Consume the token.  */
+	      cp_lexer_consume_token (parser->lexer);
+	    }
+	  else
+	    done = true;
+	  break;
+	default:
+	  done = true;
+	}
+
   /* Look for the opening `('.  */
   if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
     return;