LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Changbin Du <changbin.du@gmail.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Linux-Next Mailing List <linux-next@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Hans de Goede <hdegoede@redhat.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: linux-next: Tree for Oct 31 (vboxguest)
Date: Sun, 4 Nov 2018 11:43:44 +0900	[thread overview]
Message-ID: <CAK7LNAQp2xU_ThE_q3TmoT16cwUjKx=rB9msVB12+Y9FkaQVmw@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a1w8p8OC-9_0mtMUxEojvyVfXvF8Ka4J7TnoyZ=gr2Fow@mail.gmail.com>

On Sat, Nov 3, 2018 at 12:55 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On 11/2/18, Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
> > On Thu, Nov 1, 2018 at 11:32 PM Changbin Du <changbin.du@gmail.com> wrote:
> >> On Thu, Nov 01, 2018 at 12:32:48PM +0900, Masahiro Yamada wrote:
> >
> > How about clang?
> >
> > For clang, -Og might be equivalent to -O1 at this moment, but I am not
> > sure.
> >
> > In my understanding, Clang does not inline functions marked with 'static
> > inline'
> > for -Og (or -O1) optimization level.
> >
> > Theoretically, 'inline' keyword is a just hint for the compiler, after all.
>
> I think this means that we cannot build the kernel in that configuration,
> at least with CONFIG_OPTIMIZE_INLINING=y. Without that option,
> every 'inline' becomes 'always_inline'.
>

Sorry, I missed that fact.


At this moment of time, it is OK given the following:

 - CONFIG_OPTIMIZE_INLINING is defined only for x86
 - Clang cannot build x86 due to missing asm-goto


However, Clang with -Og
does not inline even such simple code like this:


-----test code------
static inline int foo(int x)
{
        return x;
}

int bar(int x)
{
        return foo(x);
}
-------------------



$ clang -Og -c -o bar.o  bar.c
$ objdump -d  bar.o
bar.o:     file format elf64-x86-64


Disassembly of section .text:

0000000000000000 <bar>:
   0: eb 0e                jmp    10 <foo>
   2: 66 2e 0f 1f 84 00 00 nopw   %cs:0x0(%rax,%rax,1)
   9: 00 00 00
   c: 0f 1f 40 00          nopl   0x0(%rax)

0000000000000010 <foo>:
  10: 89 f8                mov    %edi,%eax
  12: c3                    retq



-- 
Best Regards
Masahiro Yamada

  parent reply	other threads:[~2018-11-04  2:44 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-31  3:59 linux-next: Tree for Oct 31 Stephen Rothwell
2018-10-31 15:51 ` linux-next: Tree for Oct 31 (vboxguest) Randy Dunlap
2018-10-31 16:50   ` Hans de Goede
2018-10-31 19:06     ` Randy Dunlap
2018-10-31 21:41   ` Arnd Bergmann
2018-10-31 21:45     ` Randy Dunlap
2018-11-01  3:32     ` Masahiro Yamada
2018-11-01 14:29       ` Changbin Du
2018-11-02  8:25         ` Masahiro Yamada
2018-11-02 15:54           ` Arnd Bergmann
2018-11-02 23:59             ` Changbin Du
2018-11-04  2:43             ` Masahiro Yamada [this message]
2018-11-04 23:38               ` Changbin Du
2018-11-05  3:00                 ` Masahiro Yamada
2018-11-02 23:59           ` Changbin Du

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAK7LNAQp2xU_ThE_q3TmoT16cwUjKx=rB9msVB12+Y9FkaQVmw@mail.gmail.com' \
    --to=yamada.masahiro@socionext.com \
    --cc=arnd@arndb.de \
    --cc=changbin.du@gmail.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hdegoede@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-next@vger.kernel.org \
    --cc=rdunlap@infradead.org \
    --cc=rostedt@goodmis.org \
    --cc=sfr@canb.auug.org.au \
    --subject='Re: linux-next: Tree for Oct 31 (vboxguest)' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).