Re: [PATCH] fix warning about duplicate 'const'

[Richard Henderson <rth at redhat dot com>]

On Wed, Mar 10, 2004 at 11:20:03AM +0100, Gabriel Dos Reis wrote:
> I would suggest the existing practice (in nearby language) for this:
> 
>    (1) reject "direct" duplicate cv-qualifiers, .e.g.
> 
>          const const int i = 90;       // ERROR

Perhaps you meant pedwarn, not error?

The following has been through the test suite, and doesn't warn
for *any* duplicated qualifiers.  I chose this because that's
what C99 does, and that's easier to document and more forward
compatible.


r~


	* c-decl.c (grokdeclarator): Don't warn for duplicate qualifiers
	except for pedantic c90 mode.

Index: c-decl.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/c-decl.c,v
retrieving revision 1.483
diff -u -p -r1.483 c-decl.c
--- c-decl.c	9 Mar 2004 23:39:14 -0000	1.483
+++ c-decl.c	10 Mar 2004 22:15:28 -0000
@@ -3372,7 +3372,7 @@ grokdeclarator (tree declarator, tree de
 		{
 		  if (i == RID_CONST || i == RID_VOLATILE || i == RID_RESTRICT)
 		    {
-		      if (!flag_isoc99)
+		      if (pedantic && !flag_isoc99)
 			pedwarn ("duplicate `%s'", IDENTIFIER_POINTER (id));
 		    }
 		  else
@@ -3629,12 +3629,15 @@ grokdeclarator (tree declarator, tree de
   volatilep
     = !! (specbits & 1 << (int) RID_VOLATILE) + TYPE_VOLATILE (element_type);
   inlinep = !! (specbits & (1 << (int) RID_INLINE));
-  if (constp > 1 && ! flag_isoc99)
-    pedwarn ("duplicate `const'");
-  if (restrictp > 1 && ! flag_isoc99)
-    pedwarn ("duplicate `restrict'");
-  if (volatilep > 1 && ! flag_isoc99)
-    pedwarn ("duplicate `volatile'");
+  if (pedantic && !flag_isoc99)
+    {
+      if (constp > 1)
+	pedwarn ("duplicate `const'");
+      if (restrictp > 1)
+	pedwarn ("duplicate `restrict'");
+      if (volatilep > 1)
+	pedwarn ("duplicate `volatile'");
+    }
   if (! flag_gen_aux_info && (TYPE_QUALS (type)))
     type = TYPE_MAIN_VARIANT (type);
   type_quals = ((constp ? TYPE_QUAL_CONST : 0)
@@ -4087,12 +4090,15 @@ grokdeclarator (tree declarator, tree de
 
 	      if (erred)
 		error ("invalid type modifier within pointer declarator");
-	      if (constp > 1 && ! flag_isoc99)
-		pedwarn ("duplicate `const'");
-	      if (volatilep > 1 && ! flag_isoc99)
-		pedwarn ("duplicate `volatile'");
-	      if (restrictp > 1 && ! flag_isoc99)
-		pedwarn ("duplicate `restrict'");
+	      if (pedantic && !flag_isoc99)
+		{
+		  if (constp > 1)
+		    pedwarn ("duplicate `const'");
+		  if (volatilep > 1)
+		    pedwarn ("duplicate `volatile'");
+		  if (restrictp > 1)
+		    pedwarn ("duplicate `restrict'");
+		}
 
 	      type_quals = ((constp ? TYPE_QUAL_CONST : 0)
 			    | (restrictp ? TYPE_QUAL_RESTRICT : 0)
Index: testsuite/gcc.dg/c90-dupqual-1.c
===================================================================
RCS file: testsuite/gcc.dg/c90-dupqual-1.c
diff -N testsuite/gcc.dg/c90-dupqual-1.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gcc.dg/c90-dupqual-1.c	10 Mar 2004 22:15:29 -0000
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1990 -pedantic-errors" } */
+
+typedef const int CI;
+const const int c1;		/* { dg-error "duplicate" } */
+const CI c2;			/* { dg-error "duplicate" } */
+const CI *c3;			/* { dg-error "duplicate" } */
+
+typedef volatile int VI;
+volatile volatile int v1;	/* { dg-error "duplicate" } */
+volatile VI v2;			/* { dg-error "duplicate" } */
+volatile VI *v3;		/* { dg-error "duplicate" } */
Index: testsuite/gcc.dg/c99-dupqual-1.c
===================================================================
RCS file: testsuite/gcc.dg/c99-dupqual-1.c
diff -N testsuite/gcc.dg/c99-dupqual-1.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gcc.dg/c99-dupqual-1.c	10 Mar 2004 22:15:29 -0000
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
+
+typedef const int CI;
+const const int c1;		/* { dg-bogus "duplicate" } */
+const CI c2;			/* { dg-bogus "duplicate" } */
+const CI *c3;			/* { dg-bogus "duplicate" } */
+
+typedef volatile int VI;
+volatile volatile int v1;	/* { dg-bogus "duplicate" } */
+volatile VI v2;			/* { dg-bogus "duplicate" } */
+volatile VI *v3;		/* { dg-bogus "duplicate" } */
Index: testsuite/gcc.dg/gnu89-dupqual-1.c
===================================================================
RCS file: testsuite/gcc.dg/gnu89-dupqual-1.c
diff -N testsuite/gcc.dg/gnu89-dupqual-1.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gcc.dg/gnu89-dupqual-1.c	10 Mar 2004 22:15:29 -0000
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu89 -Werror" } */
+
+typedef const int CI;
+const const int c1;		/* { dg-bogus "duplicate" } */
+const CI c2;			/* { dg-bogus "duplicate" } */
+const CI *c3;			/* { dg-bogus "duplicate" } */
+
+typedef volatile int VI;
+volatile volatile int v1;	/* { dg-bogus "duplicate" } */
+volatile VI v2;			/* { dg-bogus "duplicate" } */
+volatile VI *v3;		/* { dg-bogus "duplicate" } */