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No Subject

[Pete Popov]

Hi,

I'm using a mips64 dos-hosted cross
compiler which I built on my Linux box.
The compiler has been working fine and
we haven't ran into any problems, but
there's something I don't understand and
it really frustrates me.

I'm compiling all files with "-nostdinc"
switch; the files are later linked with
"-nostdlib".   I've got my own version
of "memcpy" and a few other routines;
however, for some reason, the compiler
chooses to insert the standard libc
memcpy in some of the files.  Thus, some
files get my version of memcpy, and
other get the libc version.  There's is
no apparent difference in those files;
they include the same .h files, they are
compiled with the same switches, etc.
Any suggestions?

Thanks,

Pete

Re: your mail

[Rolf Fiedler]

On Tue, 19 May 1998, Pete Popov wrote:
> 
> Hi,
> 
> I'm using a mips64 dos-hosted cross
> compiler which I built on my Linux box.
> The compiler has been working fine and
> we haven't ran into any problems, but
> there's something I don't understand and
> it really frustrates me.
> 
> I'm compiling all files with "-nostdinc"
> switch; the files are later linked with
> "-nostdlib".   I've got my own version
> of "memcpy" and a few other routines;
> however, for some reason, the compiler
> chooses to insert the standard libc
> memcpy in some of the files.  Thus, some
> files get my version of memcpy, and
> other get the libc version.  There's is
> no apparent difference in those files;
> they include the same .h files, they are
> compiled with the same switches, etc.
> Any suggestions?

the compiler is not linking in anything from the libc, but it has builtin
functions for some very common functions. when you initialize an
array (or any other datastructure) the compiler needs to have a bcopy or
memcopy. So if the
compiler already has a target-optimized memcpy, why not use it for 
libc memcpy calls as well?
if you do not like this behaviour, turn it off using -fno-builtin

       -fno-builtin
              Don't recognize built-in functions that do not  be-
              gin  with  two leading underscores.  Currently, the
              functions affected include _exit, abort, abs, allo-
              ca,  cos,  exit,  fabs,  labs, memcmp, memcpy, sin,
              sqrt, strcmp, strcpy, and strlen.

              The `-ansi' option prevents alloca and  _exit  from
              being builtin functions.

> 
> Thanks,
> 
> Pete
> 
you're welcome
rolf

+-----------------+-----------------------------------------+
|    _____        |  Rolf Fiedler                           |
|   / ___/        |  Electronic Design Engineer             |
|  / _/           |  Ferrari electronic GmbH                |
| /_/e/r/r/a/r/i/ |  phone: +49 3328 4559 0                 |
|   electronic    |  E-Mail: Rolf.Fiedler@Ferrari.DE        |
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Re: memcpy

[Jonathan Larmour]

Pete Popov wrote:
[snip 8< ]
> I've got my own version
> of "memcpy" and a few other routines;
> however, for some reason, the compiler
> chooses to insert the standard libc
> memcpy in some of the files.  Thus, some
> files get my version of memcpy, and
> other get the libc version.

I don't think its actually the libc version that's being included. If you
look at the man page for gcc you will find that gcc itself provides builtin
versions of _exit, abort, abs, alloca, cos, exit, fabs, labs, memcmp,
memcpy, sin, sqrt, strcmp, strcpy, and strlen.

To avoid this behaviour try either -fno-builtins or -mmemcpy (I haven't
tried these though so YMMV).

Jonathan L.
-- 
Cygnus Solutions, 35 Cambridge Place, Cambridge, UK.  Tel: +44 (1223) 728762
"It is impossible to enjoy idling thoroughly unless||Home e-mail: jifl @ 
one has plenty of work to do - Jerome K. Jerome"   ||     jifvik.demon.co.uk
Help fight spam! http://spam.abuse.net/  These opinions are all my own fault

Re:

[Pete Popov]

Thanks to everyone who responded to my
mail.  I now understand the "problem" and
know how to fix it.

Thanks again,

Pete

Pete Popov wrote:

> Hi,
>
> I'm using a mips64 dos-hosted cross
> compiler which I built on my Linux box.
> The compiler has been working fine and
> we haven't ran into any problems, but
> there's something I don't understand and
> it really frustrates me.
>
> I'm compiling all files with "-nostdinc"
> switch; the files are later linked with
> "-nostdlib".   I've got my own version
> of "memcpy" and a few other routines;
> however, for some reason, the compiler
> chooses to insert the standard libc
> memcpy in some of the files.  Thus, some
> files get my version of memcpy, and
> other get the libc version.  There's is
> no apparent difference in those files;
> they include the same .h files, they are
> compiled with the same switches, etc.
> Any suggestions?
>
> Thanks,
>
> Pete