Re: [Qemu-devel] [PATCH] util: Fix compilation of envlist.c for MinGW

[Paolo Bonzini <pbonzini@redhat.com>]

Il 17/01/2013 22:18, Blue Swirl ha scritto:
> On Thu, Jan 17, 2013 at 8:54 PM, Stefan Weil <sw@weilnetz.de> wrote:
>> Am 17.01.2013 21:45, schrieb Blue Swirl:
>>
>>> On Wed, Jan 16, 2013 at 6:04 PM, Stefan Weil<sw@weilnetz.de>  wrote:
>>>>
>>>> MinGW has no strtok_r, so we need a declaration in sysemu/os-win32.h.
>>>> We must also fix the include statements in util/envlist.c to include
>>>> that file.
>>>>
>>>> We currently don't need an implementation of strtok_r because the
>>>> code is compiled but not linked for MinGW.
>>>
>>>
>>> I think it would be better to fix the build system so that unnecessary
>>> files are not compiled.
>>
>>
>> That's what I suggested first, but keeping things simple is also
>> a good argument. Perhaps we should accept that libqemuutil.a
>> can contain some unnecessary files (that's the status quo!).
> 
> This could be related. I get build errors on OpenBSD:
>   LINK  i386-bsd-user/qemu-i386
> ../libqemuutil.a(oslib-posix.o)(.text+0x540): In function `qemu_vmalloc':
> /src/qemu/util/oslib-posix.c:112: multiple definition of `qemu_vmalloc'
> bsd-user/mmap.o(.text+0x400):/src/qemu/bsd-user/mmap.c:78: first defined here
> /usr/bin/ld: Warning: size of symbol `qemu_vmalloc' changed from 260
> in bsd-user/mmap.o to 124 in ../libqemuutil.a(oslib-posix.o)

Does this fix it?

diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index 5d6cffc..1f4d4a3 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -74,7 +74,7 @@ void mmap_unlock(void)
 }
 #endif

-void *qemu_vmalloc(size_t size)
+static void *qemu_vmalloc(size_t size)
 {
     void *p;
     mmap_lock();

(A better change is of course to also rename qemu_vmalloc).

>>
>> We also get the additional benefit of more portable code.
>> Even if that portability is not needed for the moment,
>> it might be useful later.
> 
> Yes, though building as an example KVM code on Win32 may be useful one
> day, that day may be distant.

That's not the kind of extra code that Stefan is talking about.  It's
extra data structures (envlist.c) that are placed in a static library
but do not appear in any final build product.

Instead, "building KVM code on Win32" is in fact something we have been
doing for years, see kvm-stub.c.

Paolo