FROMLIST: BACKPORT: Kbuild: Support nested composite objects
Kbuild composite objects only supports one level of composite objects.
That is, a composite object may only be composed of real compilable
source files.
As a simple example, the following Kbuild description is now supported:
bar-a-y := a/bar0.o a/bar1.o
bar-b-y := b/bar2.o b/bar3.o
foo-objs := bar-a.o bar-b.o
obj-m += foo.o
Add such support by recursively searching for composite objects and
listing them in $(multi-used-*) and $(real-obj-*).
Signed-off-by: Elliot Berman <eberman@codeaurora.org>
Bug: 175420575
Change-Id: I08880422bc462c38b80f1a8bd85498250898c85e
Link: https://lore.kernel.org/linux-kbuild/1611343638-28206-3-git-send-email-eberman@codeaurora.org/
[eberman@codeaurora.org: Fix compile error so that multi-search does not
recurse when foo-y contains foo.o]
Signed-off-by: Elliot Berman <eberman@codeaurora.org>
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 2d52224..d519ebb 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -59,14 +59,24 @@
# Expand $(foo-objs) $(foo-y) by calling $(call suffix-search,foo.o,-objs -y)
suffix-search = $(foreach s,$(2),$($(1:.o=$s)))
# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
-multi-search = $(sort $(foreach m,$(1), $(if $(strip $(call suffix-search,$(m),$(2) -)), $(m))))
+# Do this recursively to find nested composite objects.
+# foo-y may contain foo.o bar.o . For backwards compatibility, don't treat this
+# foo.o as a nested object
+multi-search = $(sort $(foreach m,$(1),$(if $(strip $(call suffix-search,$(m),$(2) -)),\
+ $(if $(filter $(m),$(strip $(call suffix-search,$(m),$(2) -))),,\
+ $(m) $(call multi-search,$(call suffix-search,$(m),$(2)),$(2))))))
multi-used-y := $(call multi-search,$(obj-y),-objs -y)
multi-used-m := $(call multi-search,$(obj-m),-objs -y -m)
multi-used := $(multi-used-y) $(multi-used-m)
# Replace multi-part objects by their individual parts,
# including built-in.a from subdirectories
-real-search = $(foreach m,$(1), $(if $(strip $(call suffix-search,$(m),$(2) -)),$(call suffix-search,$(m),$(2)),$(m)))
+# Recursively search for real files. For backwards compatibility,
+# foo-y may contain foo.o bar.o . foo.o in this context is a real object, and
+# shouldn't be recursed into.
+real-search = $(foreach m,$(1), $(if $(strip $(call suffix-search,$(m),$(2) -)), \
+ $(filter $(m),$(call suffix-search,$(m),$(2))) $(call real-search,$(filter-out $(m),$(call suffix-search,$(m),$(2))),$(2)),\
+ $(m)))
real-obj-y := $(call real-search, $(obj-y),-objs -y)
real-obj-m := $(call real-search, $(obj-m),-objs -y -m)