build: do not sprinkle around GENERATED_HEADERS dependencies

Keeping GENERATED_HEADERS dependencies up-to-date everywhere is complex.
We can simply make the Makefile depend on them, and they will be built
before all other targets.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Makefile

@@ -91,19 +91,18 @@ qemu-options.def: $(SRC_PATH)/qemu-options.hx
 
 SUBDIR_RULES=$(patsubst %,subdir-%, $(TARGET_DIRS))
 
-subdir-%: $(GENERATED_HEADERS)
+subdir-%:
 	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C $* V="$(V)" TARGET_DIR="$*/" all,)
 
 ifneq ($(wildcard config-host.mak),)
 include $(SRC_PATH)/Makefile.objs
 endif
 
-$(universal-obj-y) $(common-obj-y): $(GENERATED_HEADERS)
 subdir-libcacard: $(oslib-obj-y) $(trace-obj-y) qemu-timer-common.o
 
 $(filter %-softmmu,$(SUBDIR_RULES)): $(universal-obj-y) $(trace-obj-y) $(common-obj-y) subdir-libdis
 
-$(filter %-user,$(SUBDIR_RULES)): $(GENERATED_HEADERS) $(universal-obj-y) $(trace-obj-y) subdir-libdis-user subdir-libuser
+$(filter %-user,$(SUBDIR_RULES)): $(universal-obj-y) $(trace-obj-y) subdir-libdis-user subdir-libuser
 
 ROMSUBDIR_RULES=$(patsubst %,romsubdir-%, $(ROMS))
 romsubdir-%:
@@ -142,7 +141,7 @@ libcacard.la:
 install-libcacard:
 	@echo "libtool is missing, please install and rerun configure"; exit 1
 else
-libcacard.la: $(GENERATED_HEADERS) $(oslib-obj-y) qemu-timer-common.o $(addsuffix .lo, $(basename $(trace-obj-y)))
+libcacard.la: $(oslib-obj-y) qemu-timer-common.o $(addsuffix .lo, $(basename $(trace-obj-y)))
 	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C libcacard V="$(V)" TARGET_DIR="$*/" libcacard.la,)
 
 install-libcacard: libcacard.la
@@ -151,7 +150,6 @@ endif
 ######################################################################
 
 qemu-img.o: qemu-img-cmds.h
-qemu-img.o qemu-tool.o qemu-nbd.o qemu-io.o cmd.o qemu-ga.o: $(GENERATED_HEADERS)
 
 tools-obj-y = $(oslib-obj-y) $(trace-obj-y) qemu-tool.o qemu-timer.o \
 	qemu-timer-common.o main-loop.o notify.o iohandler.o cutils.o async.o
@@ -162,7 +160,6 @@ qemu-nbd$(EXESUF): qemu-nbd.o $(tools-obj-y) $(block-obj-y)
 qemu-io$(EXESUF): qemu-io.o cmd.o $(tools-obj-y) $(block-obj-y)
 
 qemu-bridge-helper$(EXESUF): qemu-bridge-helper.o
-qemu-bridge-helper.o: $(GENERATED_HEADERS)
 
 fsdev/virtfs-proxy-helper$(EXESUF): fsdev/virtfs-proxy-helper.o fsdev/virtio-9p-marshal.o oslib-posix.o $(trace-obj-y)
 fsdev/virtfs-proxy-helper$(EXESUF): LIBS += -lcap
@@ -170,7 +167,6 @@ fsdev/virtfs-proxy-helper$(EXESUF): LIBS += -lcap
 qemu-img-cmds.h: $(SRC_PATH)/qemu-img-cmds.hx
 	$(call quiet-command,sh $(SRC_PATH)/scripts/hxtool -h < $< > $@,"  GEN   $@")
 
-$(qapi-obj-y): $(GENERATED_HEADERS)
 qapi-dir := $(BUILD_DIR)/qapi-generated
 qemu-ga$(EXESUF): LIBS = $(LIBS_QGA)
 qemu-ga$(EXESUF): QEMU_CFLAGS += -I $(qapi-dir)
@@ -203,8 +199,8 @@ $(SRC_PATH)/qapi-schema.json $(SRC_PATH)/scripts/qapi-commands.py
 
 QGALIB_OBJ=$(addprefix $(qapi-dir)/, qga-qapi-types.o qga-qapi-visit.o qga-qmp-marshal.o)
 QGALIB_GEN=$(addprefix $(qapi-dir)/, qga-qapi-types.h qga-qapi-visit.h qga-qmp-commands.h)
-$(QGALIB_OBJ): $(QGALIB_GEN) $(GENERATED_HEADERS)
-$(qga-obj-y) qemu-ga.o: $(QGALIB_GEN) $(GENERATED_HEADERS)
+$(QGALIB_OBJ): $(QGALIB_GEN)
+$(qga-obj-y) qemu-ga.o: $(QGALIB_GEN)
 
 qemu-ga$(EXESUF): qemu-ga.o $(qga-obj-y) $(tools-obj-y) $(qapi-obj-y) $(qobject-obj-y) $(version-obj-y) $(QGALIB_OBJ)
 
@@ -399,5 +395,9 @@ tar:
 	cd /tmp && tar zcvf ~/$(FILE).tar.gz $(FILE) --exclude CVS --exclude .git --exclude .svn
 	rm -rf /tmp/$(FILE)
 
+# Add a dependency on the generated files, so that they are always
+# rebuilt before other object files
+Makefile: $(GENERATED_HEADERS)
+
 # Include automatically generated dependency files
 -include $(wildcard *.d audio/*.d slirp/*.d block/*.d net/*.d ui/*.d qapi/*.d qga/*.d)

Makefile.target

 # -*- Mode: makefile -*-
 
-GENERATED_HEADERS = config-target.h
 CONFIG_NO_PCI = $(if $(subst n,,$(CONFIG_PCI)),n,y)
 CONFIG_NO_KVM = $(if $(subst n,,$(CONFIG_KVM)),n,y)
 CONFIG_NO_XEN = $(if $(subst n,,$(CONFIG_XEN)),n,y)
@@ -105,8 +104,6 @@ libobj-$(CONFIG_TCI_DIS) += tci-dis.o
 
 tci-dis.o: QEMU_CFLAGS += -I$(SRC_PATH)/tcg -I$(SRC_PATH)/tcg/tci
 
-$(libobj-y): $(GENERATED_HEADERS)
-
 # HELPER_CFLAGS is used for all the legacy code compiled with static register
 # variables
 ifneq ($(TARGET_BASE_ARCH), sparc)
@@ -143,8 +140,6 @@ obj-arm-y += arm-semi.o
 
 obj-m68k-y += m68k-sim.o m68k-semi.o
 
-$(obj-y) $(obj-$(TARGET_BASE_ARCH)-y): $(GENERATED_HEADERS)
-
 obj-y += $(addprefix ../, $(universal-obj-y))
 obj-y += $(addprefix ../libuser/, $(user-obj-y))
 obj-y += $(addprefix ../libdis-user/, $(libdis-y))
@@ -166,8 +161,6 @@ obj-y = main.o bsdload.o elfload.o mmap.o signal.o strace.o syscall.o \
 
 obj-i386-y += ioport-user.o
 
-$(obj-y) $(obj-$(TARGET_BASE_ARCH)-y): $(GENERATED_HEADERS)
-
 obj-y += $(addprefix ../, $(universal-obj-y))
 obj-y += $(addprefix ../libuser/, $(user-obj-y))
 obj-y += $(addprefix ../libdis-user/, $(libdis-y))
@@ -392,9 +385,7 @@ obj-xtensa-y += core-fsf.o
 
 main.o: QEMU_CFLAGS+=$(GPROF_CFLAGS)
 
-monitor.o: hmp-commands.h qmp-commands-old.h
-
-$(obj-y) $(obj-$(TARGET_BASE_ARCH)-y): $(GENERATED_HEADERS)
+GENERATED_HEADERS += hmp-commands.h qmp-commands-old.h
 
 obj-y += $(addprefix ../, $(universal-obj-y))
 obj-y += $(addprefix ../, $(common-obj-y))
@@ -457,5 +448,8 @@ ifdef CONFIG_TRACE_SYSTEMTAP
 	$(INSTALL_DATA) $(QEMU_PROG).stp "$(DESTDIR)$(qemu_datadir)/../systemtap/tapset"
 endif
 
+GENERATED_HEADERS += config-target.h
+Makefile: $(GENERATED_HEADERS)
+
 # Include automatically generated dependency files
 -include $(wildcard *.d */*.d)

tests/Makefile

@@ -37,7 +37,6 @@ test-qapi-obj-y =  $(qobject-obj-y) $(qapi-obj-y) $(tools-obj-y)
 test-qapi-obj-y += tests/test-qapi-visit.o tests/test-qapi-types.o
 test-qapi-obj-y += module.o
 
-$(test-obj-y): $(GENERATED_HEADERS)
 $(test-obj-y): QEMU_INCLUDES += -Itests
 
 tests/check-qint$(EXESUF): tests/check-qint.o qint.o $(tools-obj-y)