Re: [Xen-users] Compliling Xen 4.5.0 Fails

[Ian Murray <murrayie@xxxxxxxxxxx>]

----- Original Message -----
> From: Ian Campbell <ian.campbell@xxxxxxxxxx>
> To: Ian Murray <murrayie@xxxxxxxxxxx>
> Cc: "xen-users@xxxxxxxxxxxxx" <xen-users@xxxxxxxxxxxxx>
> Sent: Friday, 13 March 2015, 16:35
> Subject: Re: [Xen-users] Compliling Xen 4.5.0 Fails
> 
> On Fri, 2015-03-13 at 11:46 +0000, Ian Murray wrote:
>>  Hi,
>> 
>> 
>>  I get an error when trying to compile Xen 4.5.0 from source. It
>>  happens from the tarball and also from Git. I have tried it on two
>>  boxes with the same result (Ubuntu 12.04.5). I can compile 4.5.0-rc4
>>  with no problems. I haven't looked at the differences in Git yet...
>>  was just curious if anyone else had had the same issue.
> 
> I've not heard any one else mention it, which does seem odd. Do you set

> any interesting CFLAGS or anything when you build Xen?

Thanks for responding.

Not as far as I know. Just:

./configure
make dist
make install

I bisected it and the issue occurs when the Config.mk's debug is set to N.

Setting this to Y allows me to compile (and run) with no issue.




> 
> "-no-nused-but-set-variable" isn't a real option AFAIK, but I 
> suppose it
> is mostly likely a cut-and-paste error (dropped a "u") not something

> you've got in your build environment.

Cut and paste error, I am afraid...


gcc -O2 -fomit-frame-pointer -m64 -fno-strict-aliasing -std=gnu99 -Wall 
-Wstrict-prototypes -Wdeclaration-after-statement -Wno-unused-but-set-variable  
 -DNDEBUG -I/root/xen450/xen-4.5.0/xen/include  
-I/root/xen450/xen-4.5.0/xen/include/asm-x86/mach-generic 
-I/root/xen450/xen-4.5.0/xen/include/asm-x86/mach-default -msoft-float 
-fno-stack-protector -fno-exceptions -Wnested-externs -DHAVE_GAS_VMX 
-DHAVE_GAS_EPT -DHAVE_GAS_FSGSBASE -mno-red-zone -mno-sse -fpic 
-fno-asynchronous-unwind-tables -DGCC_HAS_VISIBILITY_ATTRIBUTE -fno-builtin 
-fno-common -Werror -Wredundant-decls -Wno-pointer-arith -pipe -g -D__XEN__ 
-include /root/xen450/xen-4.5.0/xen/include/xen/config.h -nostdinc -DHAS_ACPI 
-DHAS_GDBSX -DHAS_PASSTHROUGH -DHAS_MEM_ACCESS -DHAS_MEM_PAGING 
-DHAS_MEM_SHARING -DHAS_PCI -DHAS_IOPORTS -DHAS_PDX -MMD -MF .hvm.o.d -c hvm.c 
-o hvm.o
hvm.c: In function âhvm_create_ioreq_serverâ:
hvm.c:487:18: error: âbufioreq_pfnâ may be used uninitialised in this function 
[-Werror=uninitialized]
hvm.c:718:30: note: âbufioreq_pfnâ was declared here
cc1: all warnings being treated as errors
make[5]: *** [hvm.o] Error 1
> 
>>  Any suggestions?
> 
> Looking at the code I think the compiler is just not smart enough to
> realise that the variable is always initialised. Or at least I'm
> struggling to find a path where it isn't... But the control flow in that
> function is pretty complex so I'd not be surprised of both gcc and
> myself were flumoxed ;-)
> 
> Unless you are passing strange options to the build process then I think
> you should take this to the -devel list so the authors of the code can
> a) see if they can spot something I can't and b) consider if they can
> rewrite it a bit to unconfuse the compiler.

I am not aware of doing anything special, unless it's environmental. OTH I 
can't believe this is a general problem and nobody has noticed.

> 
>>  Apologies if this appears twice. I used an old list address to start with.
> 
> FWIW mails to xen-*@lists.{xen.org,xenproject.org,xensource.com} all get
> routed to the appropriate list in the end.

There was a huge delay in getting the reply, so I went to look at what was 
wrong with my first attempt. Turns out Yahoo is having a bad day. :)

> 
> This copy had the benefit of not being in HTML though.

> 


I'll try to remember. :)

> 
> Ian.
> 
>>  make[5]: Entering directory `/root/xen450/xen-4.5.0/xen/arch/x86/hvm'
>>  gcc -O2 -fomit-frame-pointer -m64 -fno-strict-aliasing -std=gnu99 -Wall 
> -Wstrict-prototypes -Wdeclaration-after-statement -no-nused-but-set-variable  
> -DNDEBUG -I/root/xen450/xen-4.5.0/xen/include  
> -I/root/xen450/xen-4.5.0/xen/include/asm-x86/mach-eneric 
> -I/root/xen450/xen-4.5.0/xen/include/asm-x86/mach-default -msoft-float 
> -fno-stack-protector -fno-exceptions -Wnested-xterns -DHAVE_GAS_VMX 
> -DHAVE_GAS_EPT -DHAVE_GAS_FSGSBASE -mno-red-zone -mno-sse -fpic 
> -fno-asynchronous-unwind-tables -GCC_HAS_VISIBILITY_ATTRIBUTE -fno-builtin 
> -fno-common -Werror -Wredundant-decls -Wno-pointer-arith -pipe -g -D__XEN__ 
> -include root/xen450/xen-4.5.0/xen/include/xen/config.h -nostdinc -DHAS_ACPI 
> -DHAS_GDBSX -DHAS_PASSTHROUGH -DHAS_MEM_ACCESS -HAS_MEM_PAGING 
> -DHAS_MEM_SHARING 
> -DHAS_PCI -DHAS_IOPORTS -DHAS_PDX -MMD -MF .hvm.o.d -c hvm.c -o hvm.o
>>  hvm.c: In function âhvm_create_ioreq_serverâ:
>>  hvm.c:487:18: error: âbufioreq_pfnâ may be used uninitialised in this 
> function [-Werror=uninitialized]
>>  hvm.c:718:30: note: âbufioreq_pfnâ was declared here
>>  cc1: all warnings being treated as errors
>>  make[5]: *** [hvm.o] Error 1
>> 
>>  _______________________________________________
>>  Xen-users mailing list
>>  Xen-users@xxxxxxxxxxxxx
>>  http://lists.xen.org/xen-users
>

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users