Enable -fsanitize-address-use-after-scope only if -fsanitize=address is enabled

2016-12-08  Dmitry Vyukov  <dvyukov@google.com>

	* opts.c (finish_options): Enable
	-fsanitize-address-use-after-scope only if -fsanitize=address is enabled
	(not -fsanitize=kernel-address).
	* doc/invoke.texi (-fsanitize=kernel-address):
	Don't say that it enables -fsanitize-address-use-after-scope.

From-SVN: r243441

gcc/ChangeLog

+2016-12-08  Dmitry Vyukov  <dvyukov@google.com>
+
+	* opts.c (finish_options): Enable
+	-fsanitize-address-use-after-scope only if -fsanitize=address is enabled
+	(not -fsanitize=kernel-address).
+	* doc/invoke.texi (-fsanitize=kernel-address):
+	Don't say that it enables -fsanitize-address-use-after-scope.
+
 2016-12-08  Bin Cheng  <bin.cheng@arm.com>
 
 	PR middle-end/78684

gcc/doc/invoke.texi

@@ -10640,7 +10640,6 @@ The option can't be combined with @option{-fsanitize=thread}.
 @item -fsanitize=kernel-address
 @opindex fsanitize=kernel-address
 Enable AddressSanitizer for Linux kernel.
-The option enables @option{-fsanitize-address-use-after-scope}.
 See @uref{https://github.com/google/kasan/wiki} for more details.
 
 @item -fsanitize=thread

gcc/opts.c

@@ -990,7 +990,7 @@ finish_options (struct gcc_options *opts, struct gcc_options *opts_set,
 
   /* Enable -fsanitize-address-use-after-scope if address sanitizer is
      enabled.  */
-  if (opts->x_flag_sanitize
+  if ((opts->x_flag_sanitize & SANITIZE_USER_ADDRESS)
       && !opts_set->x_flag_sanitize_address_use_after_scope)
     opts->x_flag_sanitize_address_use_after_scope = true;