Re: [Qemu-devel] [RFC PATCH v4 3/6] Makefile: introduce common-obj-m and block-obj-m for DSO

[Paolo Bonzini <pbonzini@redhat.com>]

Il 10/09/2013 15:16, Fam Zheng ha scritto:
> 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:
> 
>     $(obj)/foo.mo : $(addprefix $(obj)/, bar.o baz.o qux.o)
> 
> With target and dependencies both prefixed with $(obj)/.

Just curious why you abandoned the foo.mo-objs idea.  But anyway it can
be implemented on top, together with "dirs".

> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  Makefile      | 20 +++++++++++++++++++-
>  Makefile.objs |  2 ++
>  configure     |  6 ++++++
>  rules.mak     | 26 +++++++++++++++++++-------
>  4 files changed, 46 insertions(+), 8 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index 9e603c6..3685bbd 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -125,7 +125,9 @@ dummy := $(call unnest-vars,, \
>                  util-obj-y \
>                  qga-obj-y \
>                  block-obj-y \
> -                common-obj-y)
> +                block-obj-m \
> +                common-obj-y \
> +                common-obj-m)

Do block-obj-m and common-obj-m need to be expanded in Makefile.target too?

Perhaps unnest-vars should automatically handle both -y and -m variants;
possibly even call add-modules.  Even though it would be unused in
Makefile.target, it would keep all the logic in one place in rules.mak.

>  ifneq ($(wildcard config-host.mak),)
>  include $(SRC_PATH)/tests/Makefile
> @@ -133,6 +135,18 @@ endif
>  
>  all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all
>  
> +define add-modules
> +$(foreach o,$(filter %.o,$($1)),$(eval \
> +	$(patsubst %.o,%.mo,$o): $o))
> +$(eval modules-m += $(patsubst %.o,%.mo,$($1)))
> +endef
> +
> +dummy := $(call add-modules,block-obj-m)
> +dummy := $(call add-modules,common-obj-m)
> +
> +modules: $(patsubst %.mo,%$(DSOSUF),$(modules-m))
> +all: modules
> +
>  vl.o: QEMU_CFLAGS+=$(GPROF_CFLAGS)
>  
>  vl.o: QEMU_CFLAGS+=$(SDL_CFLAGS)
> @@ -249,6 +263,10 @@ 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 '*.mo' -type f -exec rm -f {} +
> +	find . -name '*.dll' -type f -exec rm -f {} +
> +
>  	rm -f $(TOOLS) $(HELPERS-y) qemu-ga TAGS cscope.* *.pod *~ */*~
>  	rm -Rf .libs
>  	rm -f qemu-img-cmds.h
> diff --git a/Makefile.objs b/Makefile.objs
> index 4f7a364..023166b 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -19,6 +19,8 @@ block-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o
>  block-obj-y += qemu-coroutine-sleep.o
>  block-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o
>  
> +block-obj-m = block/
> +
>  ifeq ($(CONFIG_VIRTIO)$(CONFIG_VIRTFS)$(CONFIG_PCI),yyy)
>  # Lots of the fsdev/9pcode is pulled in by vl.c via qemu_fsdev_add.
>  # only pull in the actual virtio-9p device if we also enabled virtio.
> diff --git a/configure b/configure
> index cc3cd4d..c6d4a62 100755
> --- a/configure
> +++ b/configure
> @@ -190,6 +190,8 @@ mingw32="no"
>  gcov="no"
>  gcov_tool="gcov"
>  EXESUF=""
> +DSOSUF=".so"
> +LDFLAGS_SHARED="-shared"
>  prefix="/usr/local"
>  mandir="\${prefix}/share/man"
>  datadir="\${prefix}/share"
> @@ -485,6 +487,7 @@ OpenBSD)
>  Darwin)
>    bsd="yes"
>    darwin="yes"
> +  LDFLAGS_SHARED="-bundle"
>    if [ "$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 6342d60..2be7901 100644
> --- a/rules.mak
> +++ b/rules.mak
> @@ -18,6 +18,10 @@ QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(*D)/$(*F).d
>  QEMU_INCLUDES += -I$(<D) -I$(@D)
>  
>  extract-libs = $(strip $(foreach o,$1,$($o-libs)))
> +expand-objs = $(strip $(sort $(filter %.o,$1)) \
> +			  $(if $(realpath $(filter %.mo,$1)), \
> +				$(shell cat $(realpath $(filter %.mo,$1)))) \

Why test realpath?

> +			  $(filter-out %.o %.mo,$1))
>  
>  %.o: %.c
>  	$(call quiet-command,$(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) $($@-cflags) -c -o $@ $<,"  CC    $(TARGET_DIR)$@")
> @@ -26,8 +30,8 @@ extract-libs = $(strip $(foreach o,$1,$($o-libs)))
>  
>  ifeq ($(LIBTOOL),)
>  LINK = $(call quiet-command,$(CC) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ \
> -       $(sort $(filter %.o, $1)) $(filter-out %.o, $1) $(version-obj-y) \
> -       $(call extract-libs,$^) $(LIBS),"  LINK  $(TARGET_DIR)$@")
> +       $(call expand-objs $1) $(version-obj-y) \
> +       $(call extract-libs,$1) $(LIBS),"  LINK  $(TARGET_DIR)$@")
>  else
>  LIBTOOL += $(if $(V),,--quiet)
>  %.lo: %.c
> @@ -38,12 +42,12 @@ LIBTOOL += $(if $(V),,--quiet)
>  	$(call quiet-command,$(LIBTOOL) --mode=compile --tag=CC dtrace -o $@ -G -s $<, " lt GEN $(TARGET_DIR)$@")
>  
>  LINK = $(call quiet-command,\
> -       $(if $(filter %.lo %.la,$^),$(LIBTOOL) --mode=link --tag=CC \
> +       $(if $(filter %.lo %.la,$1),$(LIBTOOL) --mode=link --tag=CC \
>         )$(CC) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ \
> -       $(sort $(filter %.o, $1)) $(filter-out %.o, $1) \
> -       $(if $(filter %.lo %.la,$^),$(version-lobj-y),$(version-obj-y)) \
> -       $(if $(filter %.lo %.la,$^),$(LIBTOOLFLAGS)) \
> -       $(call extract-libs,$^) $(LIBS),$(if $(filter %.lo %.la,$^),"lt LINK ", "  LINK  ")"$(TARGET_DIR)$@")
> +       $(call expand-objs,$1) \
> +       $(if $(filter %.lo %.la,$1),$(version-lobj-y),$(version-obj-y)) \
> +       $(if $(filter %.lo %.la,$1),$(LIBTOOLFLAGS)) \
> +       $(call extract-libs,$1) $(LIBS),$(if $(filter %.lo %.la,$1),"lt LINK ", "  LINK  ")"$(TARGET_DIR)$@")
>  endif
>  
>  %.asm: %.S
> @@ -58,6 +62,14 @@ endif
>  %.o: %.dtrace
>  	$(call quiet-command,dtrace -o $@ -G -s $<, "  GEN   $(TARGET_DIR)$@")
>  
> +%$(DSOSUF): QEMU_CFLAGS += -fPIC
> +%$(DSOSUF): LDFLAGS += $(LDFLAGS_SHARED)
> +%$(DSOSUF): %.mo
> +	$(call LINK,$^)
> +
> +%.mo:
> +	$(call quiet-command,echo $(sort $^) > $@,"  GEN    $(TARGET_DIR)$@")
> +
>  %$(EXESUF): %.o
>  	$(call LINK,$^)

Personally I find this easier to read, but I'm obviously biased.

Thanks,

Paolo