lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Sat, 17 May 2014 17:53:45 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Manuel Schölling <manuel.schoelling@....de>
Cc:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fs: Cleanup string initializations (char[] instead of
 char *)

On Sat, May 17, 2014 at 05:00:18PM +0200, Manuel Schölling wrote:
> Initializations like 'char *foo = "bar"' will create two variables: a static
> string and a pointer (foo) to that static string. Instead 'char foo[] = "bar"'
> will declare a single variable and will end up in shorter
> assembly (according to Jeff Garzik on the KernelJanitor's TODO list).

The hell it will.  Compare assembler generated e.g. for 32bit x86 before
and after.

>  {
>  	char *dp;
>  	char *status = "disabled";
> -	const char * flags = "flags: ";
> +	const char flags[] = "flags: ";

The first variant puts address of constant array into local variable
(on stack or in a register).  The second one fills local _array_ - the
string itself goes on stack.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists