[Qemu-devel] [PATCH V3 1/5] libqblock build system

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

  Libqblock was placed in new directory ./libqblock, libtool will build
dynamic library there, source files of block layer remains in ./block.
So block related source code will generate 3 sets of binary, first is old
ones used in qemu, second and third are non PIC and PIC ones in ./libqblock.
  GCC compiler flag visibility=hidden was used with special macro, to export
only symbols that was marked as PUBLIC.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 Makefile                    |   13 ++++++++-
 Makefile.objs               |    6 ++++
 libqblock/Makefile          |   64 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+), 1 deletions(-)
 create mode 100644 libqblock/Makefile
 create mode 100644 libqblock/libqblock-error.c
 create mode 100644 libqblock/libqblock.c

diff --git a/Makefile b/Makefile
index 971e92f..b0b9b8d 100644
--- a/Makefile
+++ b/Makefile
@@ -164,6 +164,17 @@ qemu-io$(EXESUF): qemu-io.o cmd.o $(tools-obj-y) $(block-obj-y)
 
 qemu-bridge-helper$(EXESUF): qemu-bridge-helper.o
 
+######################################################################
+# Support building shared library libqblock
+ifeq ($(LIBTOOL),)
+$(libqblock-lib-la):
+	@echo "libtool is missing, please install and rerun configure"; exit 1
+else
+$(libqblock-lib-la):
+	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C libqblock V="$(V)" TARGET_DIR="$*/" $(libqblock-lib-la),)
+endif
+###########################################################################
+
 vscclient$(EXESUF): $(libcacard-y) $(oslib-obj-y) $(trace-obj-y) $(tools-obj-y) qemu-timer-common.o libcacard/vscclient.o
 	$(call quiet-command,$(CC) $(LDFLAGS) -o $@ $^ $(libcacard_libs) $(LIBS),"  LINK  $@")
 
@@ -227,7 +238,7 @@ clean:
 	rm -rf qapi-generated
 	rm -rf qga/qapi-generated
 	$(MAKE) -C tests/tcg clean
-	for d in $(ALL_SUBDIRS) $(QEMULIBS) libcacard; do \
+	for d in $(ALL_SUBDIRS) $(QEMULIBS) libcacard libqblock; do \
 	if test -d $$d; then $(MAKE) -C $$d $@ || exit 1; fi; \
 	rm -f $$d/qemu-options.def; \
         done
diff --git a/Makefile.objs b/Makefile.objs
index 4412757..8a4c9fc 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -248,3 +248,9 @@ nested-vars += \
 	common-obj-y \
 	extra-obj-y
 dummy := $(call unnest-vars)
+
+#############################################################################
+# libqblock
+
+libqblock-lib-la = libqblock.la
+libqblock-lib-path = libqblock
diff --git a/libqblock/Makefile b/libqblock/Makefile
new file mode 100644
index 0000000..bf7abcc
--- /dev/null
+++ b/libqblock/Makefile
@@ -0,0 +1,64 @@
+###########################################################################
+# libqblock Makefile
+# Todo:
+#    1 trace related files is generated in this directory, move
+#  them to the root directory.
+##########################################################################
+-include ../config-host.mak
+-include $(SRC_PATH)/Makefile.objs
+-include $(SRC_PATH)/rules.mak
+
+#############################################################################
+# Library settings
+#############################################################################
+$(call set-vpath, $(SRC_PATH))
+
+#expand the foldered vars,especially ./block
+dummy := $(call unnest-vars-1)
+
+#library objects
+tools-obj-y = $(oslib-obj-y) $(trace-obj-y) qemu-tool.o qemu-timer.o \
+	qemu-timer-common.o main-loop.o notify.o \
+	iohandler.o cutils.o iov.o async.o
+tools-obj-$(CONFIG_POSIX) += compatfd.o
+
+libqblock-y=libqblock.o libqblock-error.o
+libqblock-lib-y=$(patsubst %.o,%.lo,$(libqblock-y))
+
+QEMU_OBJS=$(tools-obj-y) $(block-obj-y)
+QEMU_OBJS_FILTERED=$(filter %.o,$(QEMU_OBJS))
+QEMU_OBJS_LIB=$(patsubst %.o, %.lo,$(QEMU_OBJS_FILTERED))
+
+QEMU_CFLAGS+= -I../ -I../include
+#adding magic macro define for symbol hiding and exposing
+QEMU_CFLAGS+= -fvisibility=hidden -D LIBQB_BUILD
+
+#dependency libraries
+LIBS+=-lz $(LIBS_TOOLS)
+
+#################################################################
+# Runtime rules
+#################################################################
+clean:
+	rm -f *.lo *.o *.d *.la libqblock-test trace.c trace.c-timestamp
+	rm -rf .libs block trace
+
+all: libqblock-test
+	@true
+
+help:
+	@echo type make libqblock-test at root dirtory, libtool is required
+
+#make dir block at runtime which would hold the output of block/*.c
+block:
+	@mkdir block
+
+ifeq ($(LIBTOOL),)
+$(libqblock-lib-la):
+	@echo "libtool is missing, please install and rerun configure"; exit 1
+else
+$(libqblock-lib-la): $(libqblock-lib-y) $(QEMU_OBJS_LIB)
+	$(call quiet-command,$(LIBTOOL) --mode=link --quiet --tag=CC $(CC) -rpath $(libdir) -o $@ $^ $(LIBS),"  lt LINK $@")
+endif
+
+.PHONY: libqblock.la
diff --git a/libqblock/libqblock-error.c b/libqblock/libqblock-error.c
new file mode 100644
index 0000000..e69de29
diff --git a/libqblock/libqblock.c b/libqblock/libqblock.c
new file mode 100644
index 0000000..e69de29
-- 
1.7.1