C99 pedantry patch

["Joseph S. Myers" <jsm28 at cam dot ac dot uk>]

This patch fixes the following points about GCC's pedantic C99
behaviour (at least the first two having I believe been discussed before
but not acted on):

* `long long' is part of C99 and should not get a pedwarn in C99 mode.
* Likewise, duplicate type qualifiers are permitted by C99.
* Implicit int warnings with C99 should be pedwarns so that
  -pedantic-errors makes them into errors.
* C99 forbids `return' without a value in a function returning
  non-void, so I made this into an unconditional pedwarn if
  flag_isoc99.

(An alternative approach to some of the changes where the same warning
may be either a plain warning, or a pedwarn in C99, would be a
pedwarn_c99 or similar function, which does pedwarn () if flag_isoc99
and warning () otherwise.)

Bootstrapped and C testsuite run on i686-pc-linux-gnu; no regressions.

If this is committed, I believe the following changes can be made to my
patch <URL:http://gcc.gnu.org/ml/gcc-patches/2000-06/msg00350.html> to
c9xstatus.html: "idempotent type qualifiers" and "return without
expression not permitted in function that returns a value" can both be
listed as Done instead of Missing.

2000-06-14  Joseph S. Myers  <jsm28@cam.ac.uk>

	* c-decl.c (grokdeclarator): Don't warn about `long long' in C99.
	Make warnings about implicit int be pedwarns in C99.  Don't warn
	about duplicate type qualifiers in C99.
	(start_function): Make warning about implict int return type be a
	pedwarn in C99.
	* c-lex.c (yylex): Don't warn about `long long' in C99.
	* c-typeck.c (c_expand_return): In C99, always pedwarn about
	`return' with no value in function returning non-void.

--- c-decl.c.orig	Tue Jun 13 00:31:30 2000
+++ c-decl.c	Thu Jun 15 11:15:53 2000
@@ -3952,7 +3952,8 @@ grokdeclarator (declarator, declspecs, d
 		      error ("`long long long' is too long for GCC");
 		    else
 		      {
-			if (pedantic && ! in_system_header && warn_long_long)
+			if (pedantic && ! flag_isoc99 && ! in_system_header
+			    && warn_long_long)
 			  pedwarn ("ANSI C does not support `long long'");
 			longlong = 1;
 		      }
@@ -4014,7 +4015,9 @@ grokdeclarator (declarator, declspecs, d
 	     warning since it is more explicit.  */
 	  if ((warn_implicit_int || warn_return_type) && funcdef_flag)
 	    warn_about_return_type = 1;
-	  else if (warn_implicit_int || flag_isoc99)
+	  else if (flag_isoc99)
+	    pedwarn ("type defaults to `int' in declaration of `%s'", name);
+	  else if (warn_implicit_int)
 	    warning ("type defaults to `int' in declaration of `%s'", name);
 	}
 
@@ -4165,11 +4168,11 @@ grokdeclarator (declarator, declspecs, d
   restrictp = !! (specbits & 1 << (int) RID_RESTRICT) + TYPE_RESTRICT (type);
   volatilep = !! (specbits & 1 << (int) RID_VOLATILE) + TYPE_VOLATILE (type);
   inlinep = !! (specbits & (1 << (int) RID_INLINE));
-  if (constp > 1)
+  if (constp > 1 && ! flag_isoc99)
     pedwarn ("duplicate `const'");
-  if (restrictp > 1)
+  if (restrictp > 1 && ! flag_isoc99)
     pedwarn ("duplicate `restrict'");
-  if (volatilep > 1)
+  if (volatilep > 1 && ! flag_isoc99)
     pedwarn ("duplicate `volatile'");
   if (! flag_gen_aux_info && (TYPE_QUALS (type)))
     type = TYPE_MAIN_VARIANT (type);
@@ -4523,11 +4526,11 @@ grokdeclarator (declarator, declspecs, d
 		      error ("invalid type modifier within pointer declarator");
 		    }
 		}
-	      if (constp > 1)
+	      if (constp > 1 && ! flag_isoc99)
 		pedwarn ("duplicate `const'");
-	      if (volatilep > 1)
+	      if (volatilep > 1 && ! flag_isoc99)
 		pedwarn ("duplicate `volatile'");
-	      if (restrictp > 1)
+	      if (restrictp > 1 && ! flag_isoc99)
 		pedwarn ("duplicate `restrict'");
 
 	      type_quals = ((constp ? TYPE_QUAL_CONST : 0)
@@ -5739,7 +5742,12 @@ start_function (declspecs, declarator, p
     }
 
   if (warn_about_return_type)
-    warning ("return-type defaults to `int'");
+    {
+      if (flag_isoc99)
+	pedwarn ("return-type defaults to `int'");
+      else
+	warning ("return-type defaults to `int'");
+    }
 
   /* Save the parm names or decls from this function's declarator
      where store_parm_decls will find them.  */
--- c-lex.c.orig	Tue Jun 13 00:31:30 2000
+++ c-lex.c	Wed Jun 14 23:16:26 2000
@@ -1783,7 +1783,8 @@ yylex ()
 		      {
 			if (spec_long_long)
 			  error ("three `l's in integer constant");
-			else if (pedantic && ! in_system_header && warn_long_long)
+			else if (pedantic && ! flag_isoc99
+				 && ! in_system_header && warn_long_long)
 			  pedwarn ("ANSI C forbids long long integer constants");
 			spec_long_long = 1;
 		      }
--- c-typeck.c.orig	Tue Jun 13 00:31:30 2000
+++ c-typeck.c	Wed Jun 14 23:23:40 2000
@@ -6529,8 +6529,14 @@ c_expand_return (retval)
   if (!retval)
     {
       current_function_returns_null = 1;
-      if (warn_return_type && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
-	warning ("`return' with no value, in function returning non-void");
+      if ((warn_return_type || flag_isoc99)
+	  && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
+	{
+	  if (flag_isoc99)
+	    pedwarn ("`return' with no value, in function returning non-void");
+	  else
+	    warning ("`return' with no value, in function returning non-void");
+	}
       expand_null_return ();
     }
   else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)



-- 
Joseph S. Myers
jsm28@cam.ac.uk