Re: [Qemu-devel] [RFC PATCH v3 3/5] Makefile: introduce common-obj-m and block-obj-m for DSO

[Paolo Bonzini]

Il 10/09/2013 03:02, Fam Zheng ha scritto:
> -all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all
> +# static linked mods are expanded to .o list
> +dummy := $(call expand-mod-obj,common-obj-y)
> +dummy := $(call expand-mod-obj,block-obj-y)
> +
> +modules-m = $(patsubst %.o,%$(DSOSUF),$(filter %.o,$(block-obj-m) 
> $(common-obj-m))) \
> +            $(patsubst %.mo,%$(DSOSUF),$(filter %.mo,$(block-obj-m) 
> $(common-obj-m)))
> +
> +all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all $(modules-m)
> +
> +# Generate rules for single file modules (%.so: %.o).
> +$(foreach o,$(filter %.o,$(block-obj-m) $(common-obj-m)),$(eval \
> +     $(patsubst %.o,%.so,$o): $o))
> +
> +# For multi file modules, dependencies should be listed explicitly in
> +# Makefile.objs as
> +#     foo.mo-objs := bar.o biz.o
> +$(foreach o,$(filter %.mo,$(block-obj-m) $(common-obj-m)),$(eval \
> +     $(patsubst %.mo,%.so,$o): $($o-objs)))

I agree that this foo.mo-objs variable is homogeneous with how you
handle libraries and cflags.  I like it now.

However, I don't like the many places in which you have to special-case
modules (expand-mod-obj, modules-m, etc.), and the duplication between
Makefile and Makefile.target.

I would prefer if you try doing this patch along the lines I suggested
in my review of v2, using .mo files as a placeholder and then doing the
final link either into the .so or in the executable.  This should remove
the need for at least expand-mod-obj, and probably for more of the
duplicated constructs you have.

In particular, I would like modules-m to be simply "$(block-obj-m)
$(common-obj-m)".

In the medium term, we need to find a way to avoid the duplication:

     block-obj-y = block/
     block-obj-m = block/

Perhaps by introducing a "dirs" variable that automatically triggers
recursion on all nested variables.  But this can be the topic of a
separate patch series, if you prefer.

Paolo

>  vl.o: QEMU_CFLAGS+=$(GPROF_CFLAGS)
>  
> @@ -251,6 +270,9 @@ clean:
>       rm -f qemu-options.def
>       find . -name '*.[oda]' -type f -exec rm -f {} +
>       find . -name '*.l[oa]' -type f -exec rm -f {} +
> +     find . -name '*.so' -type f -exec rm -f {} +
> +     find . -name '*.dll' -type f -exec rm -f {} +
> +
>       rm -f $(TOOLS) $(HELPERS-y) qemu-ga TAGS cscope.* *.pod *~ */*~
>       rm -Rf .libs
>       rm -f qemu-img-cmds.h
> diff --git a/Makefile.objs b/Makefile.objs
> index efd5b0f..abf59e6 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -19,6 +19,8 @@ block-obj-y += qemu-coroutine.o qemu-coroutine-lock.o 
> qemu-coroutine-io.o
>  block-obj-y += qemu-coroutine-sleep.o
>  block-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o
>  
> +block-obj-m = block/
> +
>  ifeq ($(CONFIG_VIRTIO)$(CONFIG_VIRTFS)$(CONFIG_PCI),yyy)
>  # Lots of the fsdev/9pcode is pulled in by vl.c via qemu_fsdev_add.
>  # only pull in the actual virtio-9p device if we also enabled virtio.
> @@ -83,6 +85,9 @@ common-obj-$(CONFIG_SMARTCARD_NSS) += $(libcacard-y)
>  
>  common-obj-y += qmp-marshal.o
>  common-obj-y += qmp.o hmp.o
> +
> +common-obj-m = $(block-obj-m)
> +
>  endif
>  
>  ######################################################################
> diff --git a/Makefile.target b/Makefile.target
> index 381022d..8d70560 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -150,6 +150,10 @@ include $(SRC_PATH)/Makefile.objs
>  obj-base := ..
>  dummy := $(call unnest-vars)
>  
> +# static linked mods are expanded to .o list
> +dummy := $(call expand-mod-obj,common-obj-y)
> +dummy := $(call expand-mod-obj,block-obj-y)
> +
>  all-obj-y = $(obj-y)
>  all-obj-y += $(addprefix ../, $(common-obj-y) $(block-obj-y))
>  
> diff --git a/configure b/configure
> index cc3cd4d..c6d4a62 100755
> --- a/configure
> +++ b/configure
> @@ -190,6 +190,8 @@ mingw32="no"
>  gcov="no"
>  gcov_tool="gcov"
>  EXESUF=""
> +DSOSUF=".so"
> +LDFLAGS_SHARED="-shared"
>  prefix="/usr/local"
>  mandir="\${prefix}/share/man"
>  datadir="\${prefix}/share"
> @@ -485,6 +487,7 @@ OpenBSD)
>  Darwin)
>    bsd="yes"
>    darwin="yes"
> +  LDFLAGS_SHARED="-bundle"
>    if [ "$cpu" = "x86_64" ] ; then
>      QEMU_CFLAGS="-arch x86_64 $QEMU_CFLAGS"
>      LDFLAGS="-arch x86_64 $LDFLAGS"
> @@ -584,6 +587,7 @@ fi
>  
>  if test "$mingw32" = "yes" ; then
>    EXESUF=".exe"
> +  DSOSUF=".dll"
>    QEMU_CFLAGS="-DWIN32_LEAN_AND_MEAN -DWINVER=0x501 $QEMU_CFLAGS"
>    # enable C99/POSIX format strings (needs mingw32-runtime 3.15 or later)
>    QEMU_CFLAGS="-D__USE_MINGW_ANSI_STDIO=1 $QEMU_CFLAGS"
> @@ -4175,6 +4179,8 @@ echo "LIBTOOLFLAGS=$LIBTOOLFLAGS" >> $config_host_mak
>  echo "LIBS+=$LIBS" >> $config_host_mak
>  echo "LIBS_TOOLS+=$libs_tools" >> $config_host_mak
>  echo "EXESUF=$EXESUF" >> $config_host_mak
> +echo "DSOSUF=$DSOSUF" >> $config_host_mak
> +echo "LDFLAGS_SHARED=$LDFLAGS_SHARED" >> $config_host_mak
>  echo "LIBS_QGA+=$libs_qga" >> $config_host_mak
>  echo "POD2MAN=$POD2MAN" >> $config_host_mak
>  echo "TRANSLATE_OPT_CFLAGS=$TRANSLATE_OPT_CFLAGS" >> $config_host_mak
> diff --git a/rules.mak b/rules.mak
> index 84ed998..b88ac75 100644
> --- a/rules.mak
> +++ b/rules.mak
> @@ -58,6 +58,10 @@ endif
>  %.o: %.dtrace
>       $(call quiet-command,dtrace -o $@ -G -s $<, "  GEN   $(TARGET_DIR)$@")
>  
> +%$(DSOSUF): QEMU_CFLAGS += -fPIC
> +%$(DSOSUF):
> +     $(call quiet-command,$(LD) $^ -o $@ $(LDFLAGS_SHARED),"  LD[M] 
> $(TARGET_DIR)$@")
> +
>  %$(EXESUF): %.o
>       $(call LINK,$^)
>  
> @@ -126,7 +130,11 @@ $(foreach v,$($1), \
>               $(eval $v-cflags := )) \
>       $(if $($v-libs), \
>               $(eval $2$v-libs := $($v-libs)) \
> -             $(eval $v-libs := )))
> +             $(eval $v-libs := )) \
> +     $(if $($v-objs), \
> +             $(eval $2$v-objs := $(addprefix $2,$($v-objs))) \
> +             $(eval $v-objs := )) \
> +)
>  endef
>  
>  define unnest-dir
> @@ -157,3 +165,9 @@ $(shell mkdir -p $(sort $(foreach 
> var,$(nested-vars),$(dir $($(var))))))
>  $(foreach var,$(nested-vars), $(eval \
>    -include $(addsuffix *.d, $(sort $(dir $($(var)))))))
>  endef
> +
> +define expand-mod-obj
> +$(eval pref = $(if $(obj-base),$(obj-base)/,))
> +$(eval t = $(foreach o,$($1),$(if $($(pref)$o-obj),$($(pref)$o-obj),$o)))
> +$(eval $1 = $t)
> +endef
> diff --git a/tests/Makefile b/tests/Makefile
> index 15ef039..0dda538 100644
> --- a/tests/Makefile
> +++ b/tests/Makefile
> @@ -113,6 +113,7 @@ QEMU_CFLAGS += -I$(SRC_PATH)/tests
>  nested-vars := block-obj-y
>  obj-base := ..
>  dummy := $(call unnest-vars)
> +dummy := $(call expand-mod-obj,block-obj-y)
>  
>  tests/test-x86-cpuid.o: QEMU_INCLUDES += -I$(SRC_PATH)/target-i386
>  
>