Re: [Qemu-devel] [PATCH RFC] Makefile.target: prepend $libs_softmmu to $LIBS

[Paolo Bonzini]

On 09/03/2015 15:54, Wei Liu wrote:
> I discovered a problem when trying to build QEMU statically with gcc.
> libm is an element of LIBS while libpixman-1 is an element in
> libs_softmmu. Libpixman references functions in libm, so the original
> ordering makes linking fail.
> 
> This fix is to reorder $libs_softmmu and $LIBS to make -lm appear after
> -lpixman-1. However I'm not quite sure if this is the right fix, hence
> the RFC tag.
> 
> Normally QEMU is built with c++ compiler which happens to link in libm
> (at least this is the case with g++), so building QEMU statically
> normally just works and nobody notices this issue.
> 
> Signed-off-by: Wei Liu <address@hidden>
> ---
>  Makefile.target | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Makefile.target b/Makefile.target
> index 2262d89..1083377 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -134,7 +134,7 @@ obj-$(CONFIG_KVM) += kvm-all.o
>  obj-y += memory.o savevm.o cputlb.o
>  obj-y += memory_mapping.o
>  obj-y += dump.o
> -LIBS+=$(libs_softmmu)
> +LIBS := $(libs_softmmu) $(LIBS)

A side effect of the patch is that changes to libs_softmmu do not
propagate into LIBS.  So you also need this:

diff --git a/hw/display/Makefile.objs b/hw/display/Makefile.objs
index 7ed76a9..4eb9e98 100644
--- a/hw/display/Makefile.objs
+++ b/hw/display/Makefile.objs
@@ -20,7 +20,7 @@ common-obj-$(CONFIG_ZAURUS) += tc6393xb.o
 
 ifeq ($(CONFIG_MILKYMIST_TMU2),y)
 common-obj-y += milkymist-tmu2.o
-libs_softmmu += $(GLX_LIBS)
+milkymist-tmu2.o-libs += $(GLX_LIBS)
 endif
 
 obj-$(CONFIG_OMAP) += omap_dss.o


Because there are pending changes to OpenGL detection, I'll keep
this patch queued in my tree and will probably submit it only for
2.4.

Paolo