Re: [PATCH] fs: Cleanup string initializations (char[] instead of char *)

[Al Viro <viro@ZenIV.linux.org.uk>]

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.