Fix RejectNegative handling for -Wno- options

["Joseph S. Myers" <joseph at codesourcery dot com>]

My previous option-handling patches accidentally caused -Wno- versions
of -W options marked RejectNegative to be treated like -Wno- versions
of completely unknown options: quietly ignored unless some other
warning was given, and in that case diagnosed with a warning.

I don't think that is appropriate for these options; the point of
RejectNegative markings for these options that take arguments is that
we know that the negative version is not meaningful (or hopelessly
confusing and likely to be a mistake, as in the case of "-Wno-" for
"-Wno-extra"), rather than being an option that might be known to a
later GCC version.  This patch causes such options to get errors
again, independent of whether any other diagnostics are given.

Bootstrapped with no regressions on x86_64-unknown-linux-gnu.  OK to
commit?

2010-08-29  Joseph Myers  <joseph@codesourcery.com>

	* opts.h (CL_ERR_NEGATIVE): Define.
	* opts.c (unknown_option_callback): Don't postpone warnings for
	options marked with CL_ERR_NEGATIVE.
	* opts-common.c (decode_cmdline_option): Set CL_ERR_NEGATIVE error
	for negative versions of CL_REJECT_NEGATIVE options.

testsuite:
2010-08-29  Joseph Myers  <joseph@codesourcery.com>

	* gcc.dg/opts-1.c: Expect errors, not warnings.

Index: gcc/opts-common.c
===================================================================
--- gcc/opts-common.c	(revision 163616)
+++ gcc/opts-common.c	(working copy)
@@ -197,6 +197,7 @@ decode_cmdline_option (const char **argv
   if (!value && (option->flags & CL_REJECT_NEGATIVE))
     {
       opt_index = OPT_SPECIAL_unknown;
+      errors |= CL_ERR_NEGATIVE;
       arg = argv[0];
       goto done;
     }
Index: gcc/testsuite/gcc.dg/opts-1.c
===================================================================
--- gcc/testsuite/gcc.dg/opts-1.c	(revision 163616)
+++ gcc/testsuite/gcc.dg/opts-1.c	(working copy)
@@ -5,5 +5,5 @@
 /* { dg-error "-fno-abi-version" "-fno-abi-version" { target *-*-* } 0 } */
 /* { dg-error "-fno-lto-compression-level" "-fno-lto-compression-level" { target *-*-* } 0 } */
 /* { dg-error "-fno-tree-parallelize-loops" "-fno-tree-parallelize-loops" { target *-*-* } 0 } */
-/* { dg-warning "-Wno-strict-overflow" "-Wno-strict-overflow" { target *-*-* } 0 } */
-/* { dg-warning "-Wno-strict-aliasing" "-Wno-strict-aliasing" { target *-*-* } 0 } */
+/* { dg-error "-Wno-strict-overflow" "-Wno-strict-overflow" { target *-*-* } 0 } */
+/* { dg-error "-Wno-strict-aliasing" "-Wno-strict-aliasing" { target *-*-* } 0 } */
Index: gcc/opts.c
===================================================================
--- gcc/opts.c	(revision 163616)
+++ gcc/opts.c	(working copy)
@@ -482,7 +482,8 @@ unknown_option_callback (const struct cl
 {
   const char *opt = decoded->arg;
 
-  if (opt[1] == 'W' && opt[2] == 'n' && opt[3] == 'o' && opt[4] == '-')
+  if (opt[1] == 'W' && opt[2] == 'n' && opt[3] == 'o' && opt[4] == '-'
+      && !(decoded->errors & CL_ERR_NEGATIVE))
     {
       /* We don't generate warnings for unknown -Wno-* options unless
 	 we issue diagnostics.  */
Index: gcc/opts.h
===================================================================
--- gcc/opts.h	(revision 163616)
+++ gcc/opts.h	(working copy)
@@ -102,6 +102,9 @@ extern const unsigned int cl_lang_count;
 #define CL_ERR_MISSING_ARG	(1 << 1) /* Argument required but missing.  */
 #define CL_ERR_WRONG_LANG	(1 << 2) /* Option for wrong language.  */
 #define CL_ERR_UINT_ARG		(1 << 3) /* Bad unsigned integer argument.  */
+#define CL_ERR_NEGATIVE		(1 << 4) /* Negative form of option
+					    not permitted (together
+					    with OPT_SPECIAL_unknown).  */
 
 /* Structure describing the result of decoding an option.  */
 

-- 
Joseph S. Myers
joseph@codesourcery.com