Problem adding new source files

Problem adding new source files

[Hacking, Stuart]

Hello,
 
We have beening doing some experimentation with modifications to the
migration code in the Qemu and came up against a problem.  We included
some code in a different file and are receiving the following error from
make:
 
---
Migration.o: In function `migrate_prepare_page':
/root/tmp/KVM/qemu/migration.c:367: undefined reference to
`get_cached_page'
/root/tmp/KVM/qemu/migration.c:367: undefined reference to
`get_cached_page'
/root/tmp/KVM/qemu/migration.c:367: undefined reference to
`get_cached_page'
collect2: ld returned 1 exit status
Make[2]: *** [qemu-system_x86_64] Error 1
Make[1]: *** [subdir-x86_64-softmmu] Error2
Make: *** [qemu] Error 2
---

We see from looking at the code that everything seems to be correct and
we suspect that the error is coming from the order that the files are
being compiled.  Is there any special consideration we need to take when
adding new headers and code files to the tree?  (at the minute any new
files we added are in the same directory as migration.c.)
 
We aren't sure if the kvm maintainers are using a custom makefile,
however, would it be more appropriate to post this on the Qemu mailing
list?
 
regards
Stuart
 

Stuart Hacking
SAP Research, CEC Belfast
SAP (UK) Limited
TEIC Building, University of Ulster
BT37 0QB Newtownabbey, U.K.
( +44 (28) 90930094 
stuart.hacking@sap.com <mailto:stuart.hacking@sap.com>  

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Re: Problem adding new source files

[Uri Lublin]

Hacking, Stuart wrote:
> Hello,
Hi,
>  
> We have been doing some experimentation with modifications to the
> migration code in the Qemu and came up against a problem.  We included
> some code in a different file and are receiving the following error from
> make:
>  
> ---
> Migration.o: In function `migrate_prepare_page':
> /root/tmp/KVM/qemu/migration.c:367: undefined reference to
> `get_cached_page'
> /root/tmp/KVM/qemu/migration.c:367: undefined reference to
> `get_cached_page'
> /root/tmp/KVM/qemu/migration.c:367: undefined reference to
> `get_cached_page'
> collect2: ld returned 1 exit status
> Make[2]: *** [qemu-system_x86_64] Error 1
> Make[1]: *** [subdir-x86_64-softmmu] Error2
> Make: *** [qemu] Error 2
> ---

Did you define new functions in a different .c file(s) ? Did you provide 
prototypes for all new functions ? Did you add all new files to the Makefile ?

> 
> We see from looking at the code that everything seems to be correct and
> we suspect that the error is coming from the order that the files are
> being compiled.  Is there any special consideration we need to take when
> adding new headers and code files to the tree?  (at the minute any new
> files we added are in the same directory as migration.c.)
>  
> We aren't sure if the kvm maintainers are using a custom makefile,
> however, would it be more appropriate to post this on the Qemu mailing
> list?
Speculations...
I'm sure kvm maintainer and developers (and users) use the released Makefile.

Regards,
Uri.

RE: Problem adding new source files

[Hacking, Stuart]

 

> -----Original Message-----
> From: Uri Lublin [mailto:uril@qumranet.com] 
> Sent: 18 September 2008 14:18
> To: Hacking, Stuart
> Cc: kvm@vger.kernel.org
> Subject: Re: Problem adding new source files
> 
> Hacking, Stuart wrote:
> > Hello,
> Hi,
> >  
> > We have been doing some experimentation with modifications to the 
> > migration code in the Qemu and came up against a problem.  
> We included 
> > some code in a different file and are receiving the following error 
> > from
> > make:
> >  
> > ---
> > Migration.o: In function `migrate_prepare_page':
> > /root/tmp/KVM/qemu/migration.c:367: undefined reference to 
> > `get_cached_page'
> > /root/tmp/KVM/qemu/migration.c:367: undefined reference to 
> > `get_cached_page'
> > /root/tmp/KVM/qemu/migration.c:367: undefined reference to 
> > `get_cached_page'
> > collect2: ld returned 1 exit status
> > Make[2]: *** [qemu-system_x86_64] Error 1
> > Make[1]: *** [subdir-x86_64-softmmu] Error2
> > Make: *** [qemu] Error 2
> > ---
> 
> Did you define new functions in a different .c file(s) ? Did 
> you provide prototypes for all new functions ? Did you add 
> all new files to the Makefile ?
> 

As far as I know all the code is organised properly and the function
prototypes provided in header files.  As for adding to the Makefile -
that's where we are struggling.  We have tried the following
'experiments':  adding our new source files to the 'OBJS' variable
(OBJS+=s1.o s2.o); creating a migration.o directive which depends on
s1.o and s2.o (this actually produces a slightly different error:

---
In File included from s1.h:11,
                 from s1.c:14:
Qemu-kvm.h:11:17: error: cpu.h: No such file or directory
In File included from s1.h:11,
                 from s1.c:14:
Qemu-kvm.h:18: error: expected declaration specifiers of '...' before
'CPUState'
<ommitted further cascading errors>
Make[1]: *** [arc.o] Error 1
Make[1]: Leaving directory `/root/tmp/KVM2/qemu'
Make: *** [qemu] Error 2
---

This is why we are wondering if any special consideratinos need to be
made when adding to the makefile, or if there is already a howto
somewhere?

> 
> Regards,
> Uri.
> 

Re: Problem adding new source files

[Uri Lublin]

Hacking, Stuart wrote:
>> From: Uri Lublin [mailto:uril@qumranet.com] 
>> Hacking, Stuart wrote:
>>> Hello,
>> Hi,
>>>  
>>> We have been doing some experimentation with modifications to the 
>>> migration code in the Qemu and came up against a problem.  
>> We included 
>>> some code in a different file and are receiving the following error 
>>> from
>>> make:
>>>  
>>> ---
>>> Migration.o: In function `migrate_prepare_page':
>>> /root/tmp/KVM/qemu/migration.c:367: undefined reference to 
>>> `get_cached_page'
>>> /root/tmp/KVM/qemu/migration.c:367: undefined reference to 
>>> `get_cached_page'
>>> /root/tmp/KVM/qemu/migration.c:367: undefined reference to 
>>> `get_cached_page'
>>> collect2: ld returned 1 exit status
>>> Make[2]: *** [qemu-system_x86_64] Error 1
>>> Make[1]: *** [subdir-x86_64-softmmu] Error2
>>> Make: *** [qemu] Error 2
>>> ---
>> Did you define new functions in a different .c file(s) ? Did 
>> you provide prototypes for all new functions ? Did you add 
>> all new files to the Makefile ?
>>
> 
> As far as I know all the code is organised properly and the function
> prototypes provided in header files.  As for adding to the Makefile -
> that's where we are struggling.  We have tried the following
> 'experiments':  adding our new source files to the 'OBJS' variable
> (OBJS+=s1.o s2.o); creating a migration.o directive which depends on
> s1.o and s2.o (this actually produces a slightly different error:
> 

Try just adding your new .o files (e.g: OBJS+=s1.o s2.o) to 
<kvmdir>/qemu/Makefile.target

RE: Problem adding new source files

[Hacking, Stuart]

 

> -----Original Message-----
> From: Uri Lublin [mailto:uril@qumranet.com] 
> Sent: 18 September 2008 17:01
> To: Hacking, Stuart
> Cc: kvm@vger.kernel.org
> Subject: Re: Problem adding new source files
> 
> 
> Try just adding your new .o files (e.g: OBJS+=s1.o s2.o) to 
> <kvmdir>/qemu/Makefile.target
> 
> 

Thanks, that seems to have done the trick.  Now all our coding errors
are being revealed! :-)

--Stuart