[Buildroot] [PATCH v9 6/8] Makefile: add support for top-level parallel make

[Fabio Porcedda <fabio.porcedda@gmail.com>]

To be able to use top-level parallel make we must not depend in a rule
on the order of evaluation of the prerequisites, so instead of relyng on
the left to right ordering of evaluation of the prerequisites add an
explicit rule to describe the dependencies.

Add explicit rules to describe the following dependency chain:
$(TARGETS) -> target-finalize -> rootfs-* -> target-post-image

Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
---
 Makefile     | 15 ++++++---------
 fs/common.mk |  4 ++--
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/Makefile b/Makefile
index efd5ac6..ae8b087 100644
--- a/Makefile
+++ b/Makefile
@@ -329,8 +329,6 @@ include boot/common.mk
 include linux/linux.mk
 include system/system.mk
 
-TARGETS+=target-finalize
-
 ifeq ($(BR2_ENABLE_LOCALE_PURGE),y)
 TARGETS+=target-purgelocales
 endif
@@ -347,8 +345,6 @@ endif
 
 include fs/common.mk
 
-TARGETS+=target-post-image
-
 TARGETS_CLEAN:=$(patsubst %,%-clean,$(TARGETS))
 TARGETS_SOURCE:=$(patsubst %,%-source,$(TARGETS) $(BASE_TARGETS))
 TARGETS_DIRCLEAN:=$(patsubst %,%-dirclean,$(TARGETS))
@@ -382,11 +378,12 @@ $(BUILD_DIR)/buildroot-config/auto.conf: $(BUILDROOT_CONFIG)
 
 prepare: $(BUILD_DIR)/buildroot-config/auto.conf
 
-world: $(TARGETS)
+world: target-post-image
 
 .PHONY: all world toolchain dirs clean distclean source outputmakefile \
 	legal-info legal-info-prepare legal-info-clean printvars \
-	$(BASE_TARGETS) $(TARGETS) \
+	target-finalize target-post-image \
+	$(BASE_TARGETS) $(TARGETS) $(TARGETS_ROOTFS) \
 	$(TARGETS_CLEAN) $(TARGETS_DIRCLEAN) $(TARGETS_SOURCE) $(TARGETS_LEGAL_INFO) \
 	$(BUILD_DIR) $(STAGING_DIR) $(TARGET_DIR) \
 	$(HOST_DIR) $(BINARIES_DIR) $(STAMP_DIR)
@@ -446,7 +443,7 @@ endif
 STRIP_FIND_CMD += -type f -perm /111
 STRIP_FIND_CMD += -not \( $(call findfileclauses,libpthread*.so* $(call qstrip,$(BR2_STRIP_EXCLUDE_FILES))) \) -print
 
-target-finalize:
+target-finalize: $(TARGETS)
 	rm -rf $(TARGET_DIR)/usr/include $(TARGET_DIR)/usr/share/aclocal \
 		$(TARGET_DIR)/usr/lib/pkgconfig $(TARGET_DIR)/usr/share/pkgconfig \
 		$(TARGET_DIR)/usr/lib/cmake $(TARGET_DIR)/usr/share/cmake
@@ -552,7 +549,7 @@ target-generatelocales: host-localedef
 	done
 endif
 
-target-post-image:
+target-post-image: target-finalize $(TARGETS_ROOTFS)
 	@$(foreach s, $(call qstrip,$(BR2_ROOTFS_POST_IMAGE_SCRIPT)), \
 		$(call MESSAGE,"Executing post-image script $(s)"); \
 		$(USER_HOOKS_EXTRA_ENV) $(s) $(BINARIES_DIR) $(call qstrip,$(BR2_ROOTFS_POST_SCRIPT_ARGS))$(sep))
@@ -588,7 +585,7 @@ legal-info: dirs legal-info-clean legal-info-prepare $(REDIST_SOURCES_DIR) \
 	@rm -f $(LEGAL_WARNINGS)
 
 show-targets:
-	@echo $(TARGETS)
+	@echo $(TARGETS) $(TARGETS_ROOTFS)
 
 else # ifeq ($(BR2_HAVE_DOT_CONFIG),y)
 
diff --git a/fs/common.mk b/fs/common.mk
index aa9d961..0d054b5 100644
--- a/fs/common.mk
+++ b/fs/common.mk
@@ -63,7 +63,7 @@ ROOTFS_$(2)_COMPRESS_EXT = .xz
 ROOTFS_$(2)_COMPRESS_CMD = $$(XZ) -9 -C crc32 -c
 endif
 
-$$(BINARIES_DIR)/rootfs.$(1): $$(ROOTFS_$(2)_DEPENDENCIES)
+$$(BINARIES_DIR)/rootfs.$(1): target-finalize $$(ROOTFS_$(2)_DEPENDENCIES)
 	@$$(call MESSAGE,"Generating root filesystem image rootfs.$(1)")
 	$$(foreach hook,$$(ROOTFS_$(2)_PRE_GEN_HOOKS),$$(call $$(hook))$$(sep))
 	rm -f $$(FAKEROOT_SCRIPT)
@@ -94,7 +94,7 @@ rootfs-$(1)-show-depends:
 rootfs-$(1): $$(BINARIES_DIR)/rootfs.$(1) $$(ROOTFS_$(2)_POST_TARGETS)
 
 ifeq ($$(BR2_TARGET_ROOTFS_$(2)),y)
-TARGETS += rootfs-$(1)
+TARGETS_ROOTFS += rootfs-$(1)
 endif
 endef
 
-- 
1.8.4.2