[Qemu-devel] [PATCH v12 4/8] build-sys: introduce common-obj-m and block-obj-m for DSO

[Fam Zheng]

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 specified in each sub-Makefile.objs:

    foo.mo-objs := bar.o baz.o qux.o

in the same style with foo.o-cflags and foo.o-libs. The objects here
will be prefixed with "$(obj)/" if it's a subdirectory Makefile.objs.

Also introduce --enable-modules in configure, the option will enable
support of shared object build. Otherwise objects are static linked to
executables.

Signed-off-by: Fam Zheng <address@hidden>
---
 Makefile        |  9 +++++++--
 Makefile.objs   |  2 ++
 Makefile.target |  6 +++++-
 configure       | 14 ++++++++++++++
 rules.mak       | 54 +++++++++++++++++++++++++++++++++++++++++++++---------
 5 files changed, 73 insertions(+), 12 deletions(-)

diff --git a/Makefile b/Makefile
index 44eb55e..a8488d6 100644
--- a/Makefile
+++ b/Makefile
@@ -122,7 +122,9 @@ 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)
 
 ifneq ($(wildcard config-host.mak),)
 include $(SRC_PATH)/tests/Makefile
@@ -131,7 +133,7 @@ ifeq ($(CONFIG_SMARTCARD_NSS),y)
 include $(SRC_PATH)/libcacard/Makefile
 endif
 
-all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all
+all: $(DOCS) $(TOOLS) $(HELPERS-y) recurse-all modules
 
 vl.o: QEMU_CFLAGS+=$(GPROF_CFLAGS)
 
@@ -249,6 +251,9 @@ 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 '*.mo' -type f -exec rm -f {} +
+       find . -name '*.dll' -type f -exec rm -f {} +
        rm -f $(filter-out %.tlb,$(TOOLS)) $(HELPERS-y) qemu-ga TAGS cscope.* 
*.pod *~ */*~
        rm -f fsdev/*.pod
        rm -rf .libs */.libs
diff --git a/Makefile.objs b/Makefile.objs
index 91235a6..072d2e5 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -19,6 +19,8 @@ block-obj-y += qemu-coroutine.o qemu-coroutine-lock.o 
qemu-coroutine-io.o
 block-obj-y += qemu-coroutine-sleep.o
 block-obj-y += coroutine-$(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/Makefile.target b/Makefile.target
index 87906ea..7fb9e4d 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -152,7 +152,11 @@ obj-y-save := $(obj-y)
 block-obj-y :=
 common-obj-y :=
 include $(SRC_PATH)/Makefile.objs
-dummy := $(call unnest-vars,..,block-obj-y common-obj-y)
+dummy := $(call unnest-vars,.., \
+               block-obj-y \
+               block-obj-m \
+               common-obj-y \
+               common-obj-m)
 
 # Now restore obj-y
 obj-y := $(obj-y-save)
diff --git a/configure b/configure
index f66adb7..7b8771a 100755
--- a/configure
+++ b/configure
@@ -190,6 +190,9 @@ mingw32="no"
 gcov="no"
 gcov_tool="gcov"
 EXESUF=""
+DSOSUF=".so"
+LDFLAGS_SHARED="-shared"
+modules="no"
 prefix="/usr/local"
 mandir="\${prefix}/share/man"
 datadir="\${prefix}/share"
@@ -496,6 +499,7 @@ OpenBSD)
 Darwin)
   bsd="yes"
   darwin="yes"
+  LDFLAGS_SHARED="-bundle"
   if [ "$cpu" = "x86_64" ] ; then
     QEMU_CFLAGS="-arch x86_64 $QEMU_CFLAGS"
     LDFLAGS="-arch x86_64 $LDFLAGS"
@@ -591,6 +595,7 @@ 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 $QEMU_CFLAGS"
@@ -655,6 +660,8 @@ for opt do
   ;;
   --disable-debug-info)
   ;;
+  --enable-modules) modules="yes"
+  ;;
   --cpu=*)
   ;;
   --target-list=*) target_list="$optarg"
@@ -1080,6 +1087,7 @@ echo "  --libdir=PATH            install libraries in 
PATH"
 echo "  --sysconfdir=PATH        install config in PATH$confsuffix"
 echo "  --localstatedir=PATH     install local state in PATH (set at runtime 
on win32)"
 echo "  --with-confsuffix=SUFFIX suffix for QEMU data inside datadir and 
sysconfdir [$confsuffix]"
+echo "  --enable-modules         enable modules support"
 echo "  --enable-debug-tcg       enable TCG debugging"
 echo "  --disable-debug-tcg      disable TCG debugging (default)"
 echo "  --enable-debug-info       enable debugging information (default)"
@@ -3677,6 +3685,7 @@ echo "python            $python"
 if test "$slirp" = "yes" ; then
     echo "smbd              $smbd"
 fi
+echo "module support    $modules"
 echo "host CPU          $cpu"
 echo "host big endian   $bigendian"
 echo "target list       $target_list"
@@ -3795,6 +3804,9 @@ echo "libs_softmmu=$libs_softmmu" >> $config_host_mak
 
 echo "ARCH=$ARCH" >> $config_host_mak
 
+if test "$modules" = "yes"; then
+  echo "CONFIG_MODULES=y" >> $config_host_mak
+fi
 case "$cpu" in
   aarch64 | arm | i386 | x86_64 | x32 | ppc*)
     # The TCG interpreter currently does not support ld/st optimization.
@@ -4275,6 +4287,8 @@ 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 e732261..2ff2f16 100644
--- a/rules.mak
+++ b/rules.mak
@@ -21,7 +21,11 @@ QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(*D)/$(*F).d
 # Same as -I$(SRC_PATH) -I., but for the nested source/object directories
 QEMU_INCLUDES += -I$(<D) -I$(@D)
 
-extract-libs = $(strip $(foreach o,$1,$($o-libs)))
+extract-libs = $(strip $(sort $(foreach o,$1,$($o-libs)) \
+                  $(foreach o,$(call expand-objs,$1),$($o-libs))))
+expand-objs = $(strip $(sort $(filter %.o,$1)) \
+                  $(foreach o,$(filter %.mo,$1),$($o-objs)) \
+                  $(filter-out %.o %.mo,$1))
 
 %.o: %.c
        $(call quiet-command,$(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) 
$(QEMU_DGFLAGS) $(CFLAGS) $(address@hidden) -c -o $@ $<,"  CC    
$(TARGET_DIR)$@")
@@ -30,8 +34,8 @@ 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
@@ -42,12 +46,12 @@ 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
@@ -65,6 +69,17 @@ endif
 %.o: %.dtrace
        $(call quiet-command,dtrace -o $@ -G -s $<, "  GEN   $(TARGET_DIR)$@")
 
+%$(DSOSUF): QEMU_CFLAGS += -fPIC
+%$(DSOSUF): LDFLAGS += $(LDFLAGS_SHARED)
+%$(DSOSUF): %.mo libqemustub.a
+       $(call LINK,$^)
+
+.PHONY: modules
+modules:
+
+%.mo:
+       $(call quiet-command,touch $@,"  GEN   $(TARGET_DIR)$@")
+
 %$(EXESUF): %.o
        $(call LINK,$^)
 
@@ -130,7 +145,10 @@ $(foreach v,$($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
@@ -154,6 +172,15 @@ $(if $(nested-dirs),
   $(call unnest-vars-1))
 endef
 
+define add-modules
+$(foreach o,$(filter %.o,$($1)),
+       $(eval $(patsubst %.o,%.mo,$o): $o) \
+       $(eval $(patsubst %.o,%.mo,$o)-objs := $o))
+$(foreach o,$(filter %.mo,$($1)),$(eval \
+    $o: $($o-objs)))
+$(eval modules-m += $(patsubst %.o,%.mo,$($1)))
+endef
+
 define unnest-vars
 $(eval obj := $1)
 $(eval nested-vars := $2)
@@ -165,4 +192,13 @@ $(foreach var,$(nested-vars),$(eval $(var) := $(filter-out 
%/, $($(var)))))
 $(shell mkdir -p $(sort $(foreach var,$(nested-vars),$(dir $($(var))))))
 $(foreach var,$(nested-vars), $(eval \
   -include $(addsuffix *.d, $(sort $(dir $($(var)))))))
+$(foreach v,$(filter %-m,$(nested-vars)), \
+    $(call add-modules,$v))
+
+$(if $(CONFIG_MODULES), \
+    $(eval modules: $(patsubst %.mo,%$(DSOSUF),$(modules-m))), \
+    $(foreach v,$(filter %-m,$(nested-vars)), \
+        $(eval $(patsubst %-m,%-y,$v) += $($v)) \
+        $(eval $v := )))
+
 endef
-- 
1.8.3.1