Re: [Qemu-devel] [PATCH v6 3/8] Makefile: introduce common-obj-m and block-obj-m for DSO

[Fam Zheng <famz@redhat.com>]

On Wed, 09/11 21:01, Peter Maydell wrote:
> On 11 September 2013 14:34, Fam Zheng <famz@redhat.com> wrote:
> > Add necessary rules and flags for shared object generation.
> > $(common-obj-m) will include $(block-obj-m), like $(common-obj-y) does
> > for $(block-obj-y). The new rules introduced here are:
> >
> > 0) For all %.so compiling:
> >
> >     QEMU_CFLAGS += -fPIC
> >
> > 1) %.o in $(common-obj-m) is compiled to %.o, then linked to %.so.
> >
> > 2) %.mo in $(common-obj-m) is the placeholder for %.so for pattern
> > matching in Makefile. It's linked to "-shared" with all its dependencies
> > (multiple *.o) as input. Which means the list of depended objects must
> > be ruled out in each sub-Makefile.objs with an variable:
> >
> >     foo.mo-objs := bar.o baz.o qux.o
> >
> > in the same style with foo.o-cflags and foo.o-libs.
> 
> This spectacularly breaks compilation if you don't have libtool
> (which is currently an entirely optional dependency).
> 
> Test build/configure command, for x86-64 linux:
> 
> rm -rf build/x86 && mkdir build/x86 && (cd build/x86 && LIBTOOL=
> ../../configure --target-list=arm-softmmu --enable-debug --cc='ccache
> gcc' --disable-smartcard-nss) && make -C build/x86 -j4
> 
> Fails like this:
> 
>   LINK  qemu-ga
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 0 has invalid symbol index 10
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 1 has invalid symbol index 11
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 2 has invalid symbol index 2
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 3 has invalid symbol index 2
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 4 has invalid symbol index 10
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 5 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 6 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 7 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 8 has invalid symbol index 2
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 9 has invalid symbol index 2
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 10 has invalid symbol index 11
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 11 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 12 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 13 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 14 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 15 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 16 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 17 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 18 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 19 has invalid symbol index 12
> /usr/bin/ld.bfd.real:
> /usr/lib/debug/usr/lib/x86_64-linux-gnu/Scrt1.o(.debug_info):
> relocation 20 has invalid symbol index 20
> /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/Scrt1.o:
> In function `_start':
> (.text+0x20): undefined reference to `main'
> collect2: ld returned 1 exit status
> make: *** [qemu-ga] Error 1
> 
> 
> If we make libtool mandatory then (a) we need to make configure
> bail out if it can't find it (b) we need to flag it up in the release notes
> as a new mandatory dependency.
> 
> I'd really prefer it if we could avoid it though; among other things
> MacOSX doesn't ship with a GNU libtool.
> 

It's a bug in patch 03 (missing comma, again), I'll fix it in next revision.

Thanks for testing.

Fam