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From: Remus Clearwater <remus.clearwater@gmail.com>
To: Xi Ruoyao <xry111@mengyan1223.wang>
Cc: Andrew Haley <aph@redhat.com>, gcc-help@gcc.gnu.org
Subject: Re: Which spec has defined the calling sequence of static C functions (like the extern C functions' has been defined in the Sys V ABI specs)?
Date: Sun, 30 Dec 2018 13:27:00 -0000	[thread overview]
Message-ID: <CAMjELSvfXrm4=xJYSKP31RBjWn-t8oEmfoKmzO113vCbffj_jA@mail.gmail.com> (raw)
In-Reply-To: <3a5716b0b40ec55097347012a3b800d9f23987b4.camel@mengyan1223.wang>

>
> > Furthermore, could I make the following conclusion under GCC and Linux?
> > Conclusion:
> >
> >    For the "calling" of the C static functions, it has only two
> > possibilities -- either it's been inlined by the compiler optimization
> > (i.e. not actually been called by the `call` instruction but been
> optimized
> > for the reason of speed), Or it would be actually called (with the `call`
> > instruction) under the "Function Calling Sequence" constraints which have
> > been described in the Sys V ABI specs (same as the calling of those
> extern
> > C functions).
>
> No.  The compiler may use customized calling convention to maximize the
> performance unless this function may be called in other translation units.
>

Thank you very much, Xi. This information is very useful to me. Because I
have never known the existence of such kind optimization before. It is
brilliant! Do you mind to provide an example about such optimization --
"customized calling convention about the calling of some static functions"
in GCC?

Thanks a lot :-)

  parent reply	other threads:[~2018-12-30 13:21 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-29 18:52 Remus Clearwater
2018-12-30  9:58 ` Andrew Haley
2018-12-30 10:43   ` Remus Clearwater
2018-12-30 11:30     ` Xi Ruoyao
2018-12-30 12:52       ` Andrew Haley
2018-12-30 13:21       ` Remus Clearwater
2018-12-31 10:49         ` Remus Clearwater
2018-12-30 13:27       ` Remus Clearwater [this message]
2019-01-03 13:46   ` Florian Weimer

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