[PATCH 1/2] Makefile: libfdt: build only the strict necessary

[Claudio Fontana]

when building dtc/libfdt, we were previously using dtc/Makefile,
which tries to build some artifacts that are not needed,
and can complain on stderr about the absence of tools that
are not required to build just libfdt.

Instead, build only the strict necessary to get libfdt.a .

Signed-off-by: Claudio Fontana <address@hidden>
---
 Makefile  | 21 +++++++++++++--------
 configure |  4 ----
 rules.mak |  2 ++
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/Makefile b/Makefile
index 84ef881600..7be15eeb7c 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,10 @@ ifneq ($(words $(subst :, ,$(CURDIR))), 1)
   $(error main directory cannot contain spaces nor colons)
 endif
 
+# some pattern rules in rules.mak are confused by an empty DSOSUF,
+# and UNCHECKED_GOALS for testing (docker-) can run without prior configure.
+DSOSUF ?= ".so"
+
 # Always point to the root of the build tree (needs GNU make).
 BUILD_DIR=$(CURDIR)
 
@@ -526,15 +530,17 @@ $(SOFTMMU_FUZZ_RULES): $(edk2-decompressed)
 $(TARGET_DIRS_RULES):
        $(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C $(dir $@) V="$(V)" 
TARGET_DIR="$(dir $@)" $(notdir $@),)
 
-DTC_MAKE_ARGS=-I$(SRC_PATH)/dtc VPATH=$(SRC_PATH)/dtc -C dtc V="$(V)" 
LIBFDT_srcdir=$(SRC_PATH)/dtc/libfdt
-DTC_CFLAGS=$(CFLAGS) $(QEMU_CFLAGS)
-DTC_CPPFLAGS=-I$(BUILD_DIR)/dtc -I$(SRC_PATH)/dtc -I$(SRC_PATH)/dtc/libfdt
-
+LIBFDT_objdir = dtc/libfdt
+-include $(SRC_PATH)/dtc/libfdt/Makefile.libfdt
+LIBFDT_objects = $(addprefix $(LIBFDT_objdir)/, $(LIBFDT_OBJS))
+# the name dtc/all is for backward compatibility
 .PHONY: dtc/all
-dtc/all: .git-submodule-status dtc/libfdt dtc/tests
-       $(call quiet-command,$(MAKE) $(DTC_MAKE_ARGS) 
CPPFLAGS="$(DTC_CPPFLAGS)" CFLAGS="$(DTC_CFLAGS)" LDFLAGS="$(QEMU_LDFLAGS)" 
ARFLAGS="$(ARFLAGS)" CC="$(CC)" AR="$(AR)" LD="$(LD)" $(SUBDIR_MAKEFLAGS) 
libfdt/libfdt.a,)
+dtc/all: .git-submodule-status $(LIBFDT_objdir)/libfdt.a
+$(LIBFDT_objdir)/libfdt.a: $(LIBFDT_objects)
+       $(if $(LIBFDT_objects),$(call quiet-command,rm -f $@ && $(AR) rcs $@ 
$^,"AR","$(TARGET_DIR)$@"),)
 
-dtc/%: .git-submodule-status
+$(LIBFDT_objects): | $(LIBFDT_objdir)
+$(LIBFDT_objdir): .git-submodule-status
        @mkdir -p $@
 
 # Overriding CFLAGS causes us to lose defines added in the sub-makefile.
@@ -821,7 +827,6 @@ distclean: clean
        rm -rf $$d || exit 1 ; \
         done
        rm -Rf .sdk
-       if test -f dtc/version_gen.h; then $(MAKE) $(DTC_MAKE_ARGS) clean; fi
 
 KEYMAPS=da     en-gb  et  fr     fr-ch  is  lt  no  pt-br  sv \
 ar      de     en-us  fi  fr-be  hr     it  lv  nl         pl  ru     th \
diff --git a/configure b/configure
index 233c671aaa..cf32bfb75b 100755
--- a/configure
+++ b/configure
@@ -4278,10 +4278,6 @@ EOF
       if test -d "${source_path}/dtc/libfdt" || test -e "${source_path}/.git" 
; then
           fdt=git
           mkdir -p dtc
-          if [ "$pwd_is_source_path" != "y" ] ; then
-              symlink "$source_path/dtc/Makefile" "dtc/Makefile"
-              symlink "$source_path/dtc/scripts" "dtc/scripts"
-          fi
           fdt_cflags="-I\$(SRC_PATH)/dtc/libfdt"
           fdt_ldflags="-L\$(BUILD_DIR)/dtc/libfdt"
           fdt_libs="$fdt_libs"
diff --git a/rules.mak b/rules.mak
index 694865b63e..61eb474ba4 100644
--- a/rules.mak
+++ b/rules.mak
@@ -105,6 +105,8 @@ LINK = $(call quiet-command, $(LINKPROG) $(CFLAGS) 
$(QEMU_LDFLAGS) -o $@ \
 
 DSO_OBJ_CFLAGS := -fPIC -DBUILD_DSO
 module-common.o: CFLAGS += $(DSO_OBJ_CFLAGS)
+
+# Note: DSOSUF must not be empty, or these rules will try to match too much
 %$(DSOSUF): QEMU_LDFLAGS += $(LDFLAGS_SHARED)
 %$(DSOSUF): %.mo
        $(call LINK,$^)
-- 
2.16.4