Re: [Qemu-devel] [PATCH v2] rules.mak: Force CFLAGS for all objects in DSO

[Andreas Färber]

Am 07.05.2015 um 08:55 schrieb Fam Zheng:
> Because of the trick of process-archive-undefs, all .mo objects, even
> with --enable-modules, are dependencies of executables.
> 
> This breaks CFLAGS propogation because the compiling of module object
> will happen too early before building for DSO.
> 
> With GCC 5, the linking would fail because .o doesn't have -fPIC. Also,
> BUILD_DSO will be missed. (module-common.o will have it, so the stamp
> symbol was still liked in .so).

Did you mean "linked"?

Cheers,
Andreas

> 
> Fix the problem by forcing the CFLAGS on individual .o-cflags during
> unnest-vars.
> 
> Reported-by: Alexander Graf <address@hidden>
> Signed-off-by: Fam Zheng <address@hidden>
> 
> ---
> 
> v2: Simplify as Paolo suggested, while keeping the CFLAGS of
> module-common.o
> ---
>  rules.mak | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/rules.mak b/rules.mak
> index 3a05627..aec27f8 100644
> --- a/rules.mak
> +++ b/rules.mak
> @@ -102,7 +102,8 @@ endif
>  %.o: %.dtrace
>       $(call quiet-command,dtrace -o $@ -G -s $<, "  GEN   $(TARGET_DIR)$@")
>  
> -%$(DSOSUF): CFLAGS += -fPIC -DBUILD_DSO
> +DSO_OBJ_CFLAGS := -fPIC -DBUILD_DSO
> +module-common.o: CFLAGS += $(DSO_OBJ_CFLAGS)
>  %$(DSOSUF): LDFLAGS += $(LDFLAGS_SHARED)
>  %$(DSOSUF): %.mo
>       $(call LINK,$^)
> @@ -351,6 +352,7 @@ define unnest-vars
>          # For non-module build, add -m to -y
>          $(if $(CONFIG_MODULES),
>               $(foreach o,$($v),
> +                   $(eval $($o-objs): CFLAGS += $(DSO_OBJ_CFLAGS))
>                     $(eval $o: $($o-objs)))
>               $(eval $(patsubst %-m,%-y,$v) += $($v))
>               $(eval modules: $($v:%.mo=%$(DSOSUF))),
> 


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