re PR middle-end/7651 (Define -Wextra strictly in terms of other warning flags)

2006-12-22  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR middle-end/7651
	* c.opt (Wclobbered): New.
	* doc/invoke.texi (Wclobbered): Document it.
	(Wextra): Enabled by -Wextra.
	* c-opts.c (c_common_post_options): Enabled by -Wextra.
	* flow.c (rest_of_handle_life): Replace Wextra with Wclobbered.
	* function.c (setjmp_vars_warning): Only warn for Wclobbered.
	(setjmp_args_warning): Likewise.

testsuite/

	* gcc.dg/attr-returns_twice-1.c: Replace Wextra with Wclobbered.
	* gcc.dg/setjmp-1.c: Add explicit Wclobbered.

From-SVN: r120151

gcc/ChangeLog

@@ -1,3 +1,14 @@
+2006-12-22  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR middle-end/7651
+	* c.opt (Wclobbered): New.
+	* doc/invoke.texi (Wclobbered): Document it.
+	(Wextra): Enabled by -Wextra.
+	* c-opts.c (c_common_post_options): Enabled by -Wextra.
+	* flow.c (rest_of_handle_life): Replace Wextra with Wclobbered.
+	* function.c (setjmp_vars_warning): Only warn for Wclobbered.
+	(setjmp_args_warning): Likewise.
+	
 2006-12-22  Kazu Hirata  <kazu@codesourcery.com>
 
 	* config/elfos.h, config/spu/spu.c, tree-ssa-operands.h,

gcc/c-opts.c

@@ -1025,9 +1025,11 @@ c_common_post_options (const char **pfilename)
   if (flag_objc_exceptions && !flag_objc_sjlj_exceptions)
     flag_exceptions = 1;
 
-  /* -Wextra implies -Wempty-body, -Wsign-compare, 
+  /* -Wextra implies -Wclobbered, -Wempty-body, -Wsign-compare, 
      -Wmissing-field-initializers and -Woverride-init, 
      but not if explicitly overridden.  */
+  if (warn_clobbered == -1)
+    warn_clobbered = extra_warnings;
   if (warn_empty_body == -1)
     warn_empty_body = extra_warnings;
   if (warn_sign_compare == -1)

gcc/c.opt

@@ -141,6 +141,10 @@ Wchar-subscripts
 C ObjC C++ ObjC++ Var(warn_char_subscripts)
 Warn about subscripts whose type is \"char\"
 
+Wclobbered
+C ObjC C++ ObjC++ Var(warn_clobbered) Init(-1)
+Warn about variables that might be changed by \"longjmp\" or \"vfork\"
+
 Wcomment
 C ObjC C++ ObjC++
 Warn about possibly nested block comments, and C++ comments spanning more than one physical line

gcc/doc/invoke.texi

@@ -222,7 +222,8 @@ Objective-C and Objective-C++ Dialects}.
 @xref{Warning Options,,Options to Request or Suppress Warnings}.
 @gccoptlist{-fsyntax-only  -pedantic  -pedantic-errors @gol
 -w  -Wextra  -Wall  -Waggregate-return -Walways-true -Wno-attributes @gol
--Wc++-compat -Wcast-align  -Wcast-qual  -Wchar-subscripts  -Wcomment @gol
+-Wc++-compat -Wcast-align  -Wcast-qual  -Wchar-subscripts @gol
+-Wclobbered  -Wcomment @gol
 -Wconversion  -Wno-deprecated-declarations @gol
 -Wdisabled-optimization  -Wno-div-by-zero  @gol
 -Wempty-body  -Wno-endif-labels @gol
@@ -2925,6 +2926,7 @@ A pointer is compared against integer zero with @samp{<}, @samp{<=},
 
 @item
 A variable might be changed by @samp{longjmp} or @samp{vfork}.
+This warning can be independently controlled by @option{-Wclobbered}.
 
 @item
 Any of several floating-point events that often indicate errors, such as
@@ -3157,6 +3159,11 @@ only if you have been very careful about using @code{const} in
 declarations and prototypes.  Otherwise, it will just be a nuisance;
 this is why we did not make @option{-Wall} request these warnings.
 
+@item -Wclobbered
+@opindex Wclobbered
+Warn for variables that might be changed by @samp{longjmp} or
+@samp{vfork}.  This warning is also enabled by @option{-Wextra}.
+
 @item -Wconversion
 @opindex Wconversion
 Warn for implicit conversions that may alter a value. This includes

gcc/flow.c

@@ -4695,7 +4695,7 @@ rest_of_handle_life (void)
     cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_UPDATE_LIFE | CLEANUP_LOG_LINKS
                  | (flag_thread_jumps ? CLEANUP_THREADING : 0));
 
-  if (extra_warnings)
+  if (warn_clobbered)
     {
       setjmp_vars_warning (DECL_INITIAL (current_function_decl));
       setjmp_args_warning ();

gcc/function.c

@@ -3536,9 +3536,8 @@ setjmp_vars_warning (tree block)
 	  && DECL_RTL_SET_P (decl)
 	  && REG_P (DECL_RTL (decl))
 	  && regno_clobbered_at_setjmp (REGNO (DECL_RTL (decl))))
-	warning (0, "variable %q+D might be clobbered by %<longjmp%>"
-		 " or %<vfork%>",
-		 decl);
+	warning (OPT_Wclobbered, "variable %q+D might be clobbered by" 
+                 " %<longjmp%> or %<vfork%>", decl);
     }
 
   for (sub = BLOCK_SUBBLOCKS (block); sub; sub = TREE_CHAIN (sub))
@@ -3557,7 +3556,8 @@ setjmp_args_warning (void)
     if (DECL_RTL (decl) != 0
 	&& REG_P (DECL_RTL (decl))
 	&& regno_clobbered_at_setjmp (REGNO (DECL_RTL (decl))))
-      warning (0, "argument %q+D might be clobbered by %<longjmp%> or %<vfork%>",
+      warning (OPT_Wclobbered, 
+               "argument %q+D might be clobbered by %<longjmp%> or %<vfork%>",
 	       decl);
 }
 

gcc/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2006-12-22  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR middle-end/7651
+	* gcc.dg/attr-returns_twice-1.c: Replace Wextra with Wclobbered.
+	* gcc.dg/setjmp-1.c: Add explicit Wclobbered.
+
 2006-12-21  Andrew Pinski  <pinskia@gmail.com>
 
 	PR C++/30168

gcc/testsuite/gcc.dg/attr-returns_twice-1.c

@@ -1,5 +1,5 @@
 /* { dg-do compile { target i?86-*-* x86_64-*-* } } */
-/* { dg-options "-W" } */
+/* { dg-options "-Wclobbered" } */
 
 int newsetjmp(void) __attribute__((returns_twice));
 void g(int);

gcc/testsuite/gcc.dg/setjmp-1.c

@@ -2,7 +2,7 @@
    Inspired by cse.c:simplify_relational_operation. */
 
 /* { dg-do compile } */
-/* { dg-options "-O -W -Wall" } */
+/* { dg-options "-O -Wclobbered -Wextra -Wall" } */
 
 #include <setjmp.h>