Re: [Qemu-devel] [PATCH v5 2/9] make: ensure all members of libqemuutil.a are linked

[Eric Blake <eblake@redhat.com>]

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On 08/26/2015 09:05 AM, Daniel P. Berrange wrote:
> The libqemuutil.a archive may contain QOM objects which are
> only indirectly referenced via __attribute__((constructor))
> annotations. Despite the constructor annotation the linker
> will think these objects are unused by the executable and
> so drop them when linking, to the system emulator. As a
> result the objects in question will be missing from QOM.
> 
> Using the -Wl,--whole-archive flag instructs the linker
> to pull in everything in libqemuutil.a regardless of
> whether it thinks it is used or not.
> 
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  Makefile.target | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/Makefile.target b/Makefile.target
> index 3e7aafd..5b08f0f 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -180,8 +180,13 @@ all-obj-$(CONFIG_SOFTMMU) += $(block-obj-y)
>  $(QEMU_PROG_BUILD): config-devices.mak
>  
>  # build either PROG or PROGW
> +# We must use --whole-archive with libqemuutil.a otherwise the
> +# linker will drop any objects from the archive which are only
> +# indirectly referenced via __attribute__(constructor) annotations
>  $(QEMU_PROG_BUILD): $(all-obj-y) ../libqemuutil.a ../libqemustub.a
> -	$(call LINK, $(filter-out %.mak, $^))
> +	$(call LINK, $(filter-out %.mak, $(sort $(all-obj-y)))) \

Why the added $(sort)? Should that be a separate patch?

> +		-Wl,--whole-archive ../libqemuutil.a -Wl,--no-whole-archive \
> +		../libqemustub.a

Otherwise makes sense to me.
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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