[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <1417955413.31745.25.camel@perches.com>
Date: Sun, 07 Dec 2014 04:30:13 -0800
From: Joe Perches <joe@...ches.com>
To: Julia Lawall <julia.lawall@...6.fr>
Cc: SF Markus Elfring <elfring@...rs.sourceforge.net>,
Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
Paul Mackerras <paulus@...ba.org>, linux-ppp@...r.kernel.org,
netdev@...r.kernel.org, Eric Dumazet <eric.dumazet@...il.com>,
LKML <linux-kernel@...r.kernel.org>,
kernel-janitors@...r.kernel.org
Subject: Re: [PATCH v2 1/6] net-PPP: Replacement of a printk() call by
pr_warn() in mppe_rekey()
On Sun, 2014-12-07 at 11:44 +0100, Julia Lawall wrote:
> > A negative to that approach is inlined functions would
> > take the function name of the parent not keep the
> > inlined function name.
>
> I tried the following:
>
> #include <stdio.h>
>
> inline int foo() {
> printf("%s %x\n",__func__,0x12345);
> }
>
> int main () {
> foo();
> }
>
> The assembly code generated for main is:
>
> 0000000000400470 <main>:
> 400470: b9 45 23 01 00 mov $0x12345,%ecx
> 400475: ba 4b 06 40 00 mov $0x40064b,%edx
> 40047a: be 44 06 40 00 mov $0x400644,%esi
> 40047f: bf 01 00 00 00 mov $0x1,%edi
> 400484: 31 c0 xor %eax,%eax
> 400486: e9 d5 ff ff ff jmpq 400460 <__printf_chk@plt>
>
> That is, the call to foo seems tom be inlined.
>
> But the output is:
>
> foo 12345
>
> So it seems that __func__ is determined before inlining.
True, and that's what I intended to describe.
If you did that with a kernel module and replaced
"%s, __func__" with "%pf, __builtin_return_address(0)"
when built with kallsyms you should get:
"modname 12345" when most would expect "foo 12345"
when built without kallsyms, that output should be
"<address> 12345"
but the object code should be smaller.
--
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