Add -Wother so -Wnone suppresses all warnings.

Reported by George Neuner at
<http://lists.gnu.org/archive/html/bug-bison/2010-08/msg00002.html>.
* NEWS (2.5): Document.
* THANKS (George Neuner): Add.
* doc/bison.texinfo (Bison Options): Document.
* src/complain.c, src/complain.h
(warn_at, warn_at_indent, warn): Suppress warning if -Wno-other.
(midrule_value_at): New warning function, similar to yacc_at in
that it's controlled by its own warning category.
* src/getargs.c (warnings_flag): Initialize to warnings_other.
(warnings_args, warnings_types): Add entry for warnings_other.
(usage): Update.
* src/getargs.h (enum warnings): Add entry for warnings_other.
* src/gram.c (grammar_rules_useless_report): If -Wno-other, then
don't print useless rules.
* src/reader.c (symbol_should_be_used): Rather than adjusting the
return value based on whether midrule value warnings are enabled,
accept a new parameter for telling the caller whether true is
being returned for a potential midrule warning.
(grammar_rule_check): Use midrule_value_at for midrule value
warnings, and continue to use warn_at for all other warnings.  Let
them check whether the warnings are enabled.
* tests/local.at (AT_BISON_CHECK): Update documentation.
(AT_BISON_CHECK_NO_XML): Check that -Wnone and --warnings=none
disable all warnings exercised in the test suite.
(cherry picked from commit 8ffd7912e3)

src/complain.c

@@ -109,6 +109,8 @@ set_warning_issued (void)
 void
 warn_at (location loc, const char *message, ...)
 {
+  if (!(warnings_flag & warnings_other))
+    return;
   set_warning_issued ();
   ERROR_MESSAGE (&loc, _("warning"), message);
 }
@@ -117,6 +119,8 @@ void
 warn_at_indent (location loc, unsigned *indent,
                 const char *message, ...)
 {
+  if (!(warnings_flag & warnings_other))
+    return;
   set_warning_issued ();
   indent_ptr = indent;
   ERROR_MESSAGE (&loc, _("warning"), message);
@@ -125,6 +129,8 @@ warn_at_indent (location loc, unsigned *indent,
 void
 warn (const char *message, ...)
 {
+  if (!(warnings_flag & warnings_other))
+    return;
   set_warning_issued ();
   ERROR_MESSAGE (NULL, _("warning"), message);
 }
@@ -178,6 +184,14 @@ yacc_at (location loc, const char *message, ...)
     }
 }
 
+void
+midrule_value_at (location loc, const char *message, ...)
+{
+  if (!(warnings_flag & warnings_midrule_values))
+    return;
+  set_warning_issued ();
+  ERROR_MESSAGE (&loc, _("warning"), message);
+}
 
 /*-------------------------------------------------.
 | A severe error has occurred, we cannot proceed.  |

src/complain.h

@@ -25,7 +25,8 @@
 extern "C" {
 # endif
 
-/** Informative messages, but we proceed.  */
+/** Informative messages, but we proceed.  Report iff
+    <tt>warnings_flag & warnings_other</tt>.  */
 
 void warn (char const *format, ...)
   __attribute__ ((__format__ (__printf__, 1, 2)));
@@ -61,6 +62,11 @@ void complain_at_indent (location loc, unsigned *indent,
 void yacc_at (location loc, char const *format, ...)
   __attribute__ ((__format__ (__printf__, 2, 3)));
 
+/** A midrule-value warning.  Report iff
+    <tt>warnings_flag & warnings_midrule_values</tt>.  */
+
+void midrule_value_at (location loc, char const *format, ...)
+  __attribute__ ((__format__ (__printf__, 2, 3)));
 
 /** A fatal error, causing immediate exit.  */
 

src/getargs.c

@@ -59,7 +59,7 @@ bool glr_parser = false;
 
 int report_flag = report_none;
 int trace_flag = trace_none;
-int warnings_flag = warnings_none;
+int warnings_flag = warnings_other;
 
 static struct bison_language const valid_languages[] = {
   { "c", "c-skel.m4", ".c", ".h", true },
@@ -230,6 +230,7 @@ static const char * const warnings_args[] =
   "none            - no warnings",
   "midrule-values  - unset or unused midrule values",
   "yacc            - incompatibilities with POSIX Yacc",
+  "other           - all other warnings",
   "all             - all of the above",
   "error           - warnings are errors",
   0
@@ -240,6 +241,7 @@ static const int warnings_types[] =
   warnings_none,
   warnings_midrule_values,
   warnings_yacc,
+  warnings_other,
   warnings_all,
   warnings_error
 };
@@ -330,6 +332,7 @@ Output:\n\
 Warning categories include:\n\
   `midrule-values'  unset or unused midrule values\n\
   `yacc'            incompatibilities with POSIX Yacc\n\
+  `other'           all other warnings (enabled by default)\n\
   `all'             all the warnings\n\
   `no-CATEGORY'     turn off warnings in CATEGORY\n\
   `none'            turn off all the warnings\n\

src/getargs.h

@@ -119,6 +119,7 @@ enum warnings
     warnings_error            = 1 << 0, /**< Warnings are treated as errors.  */
     warnings_midrule_values   = 1 << 1, /**< Unset or unused midrule values.  */
     warnings_yacc             = 1 << 2, /**< POSIXME.  */
+    warnings_other            = 1 << 3, /**< All other warnings.  */
     warnings_all              = ~warnings_error /**< All above warnings.  */
   };
 /** What warnings are issued.  */

src/gram.c

@@ -24,6 +24,7 @@
 #include <quotearg.h>
 
 #include "complain.h"
+#include "getargs.h"
 #include "gram.h"
 #include "print-xml.h"
 #include "reader.h"
@@ -310,8 +311,11 @@ grammar_rules_useless_report (const char *message)
     if (!rules[r].useful)
       {
         warn_at (rules[r].location, "%s: ", message);
-        rule_print (&rules[r], stderr);
-        fflush (stderr);
+        if (warnings_flag & warnings_other)
+          {
+            rule_print (&rules[r], stderr);
+            fflush (stderr);
+          }
       }
 }
 

src/reader.c

@@ -250,22 +250,25 @@ grammar_current_rule_begin (symbol *lhs, location loc,
 /*----------------------------------------------------------------------.
 | A symbol should be used if either:                                    |
 |   1. It has a destructor.                                             |
-|   2. --warnings=midrule-values and the symbol is a mid-rule symbol    |
-|      (i.e., the generated LHS replacing a mid-rule action) that was   |
-|      assigned to or used, as in "exp: { $$ = 1; } { $$ = $1; }".      |
+|   2. The symbol is a mid-rule symbol (i.e., the generated LHS         |
+|      replacing a mid-rule action) that was assigned to or used, as in |
+|      "exp: { $$ = 1; } { $$ = $1; }".                                 |
 `----------------------------------------------------------------------*/
 
 static bool
-symbol_should_be_used (symbol_list const *s)
+symbol_should_be_used (symbol_list const *s, bool *midrule_warning)
 {
   if (symbol_destructor_get (s->content.sym)->code)
     return true;
-  if (warnings_flag & warnings_midrule_values)
-    return ((s->midrule && s->midrule->action_props.is_value_used)
-	    || (s->midrule_parent_rule
-		&& symbol_list_n_get (s->midrule_parent_rule,
-				      s->midrule_parent_rhs_index)
-                     ->action_props.is_value_used));
+  if ((s->midrule && s->midrule->action_props.is_value_used)
+      || (s->midrule_parent_rule
+          && symbol_list_n_get (s->midrule_parent_rule,
+                                s->midrule_parent_rhs_index)
+               ->action_props.is_value_used))
+    {
+      *midrule_warning = true;
+      return true;
+    }
   return false;
 }
 
@@ -309,16 +312,21 @@ grammar_rule_check (const symbol_list *r)
     symbol_list const *l = r;
     int n = 0;
     for (; l && l->content.sym; l = l->next, ++n)
-      if (! (l->action_props.is_value_used
-	     || !symbol_should_be_used (l)
-	     /* The default action, $$ = $1, `uses' both.  */
-	     || (!r->action_props.code && (n == 0 || n == 1))))
-	{
-	  if (n)
-	    warn_at (r->location, _("unused value: $%d"), n);
-	  else
-	    warn_at (r->location, _("unset value: $$"));
-	}
+      {
+        bool midrule_warning = false;
+        if (!l->action_props.is_value_used
+            && symbol_should_be_used (l, &midrule_warning)
+            /* The default action, $$ = $1, `uses' both.  */
+            && (r->action_props.code || (n != 0 && n != 1)))
+          {
+            void (*warn_at_ptr)(location, char const*, ...) =
+              midrule_warning ? midrule_value_at : warn_at;
+            if (n)
+              warn_at_ptr (r->location, _("unused value: $%d"), n);
+            else
+              warn_at_ptr (r->location, _("unset value: $$"));
+          }
+      }
   }
 
   /* See comments in grammar_current_rule_prec_set for how POSIX