+# fix-paths
+# Usage: $(call fix-paths, obj_path, src_path, vars)
+# Add prefix @obj_path to all objects in @vars, and add prefix @src_path to all
+# directories in @vars.
+define fix-paths
+ $(foreach v,$3,
+ $(foreach o,$($v),
+ $(if $($o-libs),
+ $(eval $1$o-libs := $(value $o-libs)))
+ $(if $($o-cflags),
+ $(eval $1$o-cflags := $(value $o-cflags)))
+ $(if $($o-objs),
+ $(eval $1$o-objs := $(addprefix $1,$(value $o-objs)))))
+ $(eval $v := $(addprefix $1,$(filter-out %/,$(value $v))) \
+ $(addprefix $2,$(filter %/,$(value $v)))))
endef
-define process-modules
-$(foreach o,$(filter %.o,$($1)),
- $(eval $(patsubst %.o,%.mo,$o): $o) \
- $(eval $(patsubst %.o,%.mo,$o)-objs := $o))
-$(foreach o,$(filter-out $(modules-m), $(patsubst %.o,%.mo,$($1))), \
- $(eval $o-objs += module-common.o)
- $(eval $o: $($o-objs))
- $(eval modules-objs-m += $($o-objs))
- $(eval modules-m += $o)
- $(eval $o:; $$(call quiet-command,touch $$@," GEN $$(TARGET_DIR)$$@"))
- $(if $(CONFIG_MODULES),$(eval modules: $(patsubst %.mo,%$(DSOSUF),$o)))) \
-$(eval modules-objs-m := $(sort $(modules-objs-m)))
-$(foreach o,$(modules-objs-m), \
- $(if $(CONFIG_MODULES),$(eval $o-cflags := $(call maybe-add,
$(DSO_CFLAGS), $($o-cflags)))))
-$(eval $(patsubst %-m,%-$(call lnot,$(CONFIG_MODULES)),$1) += $($1))
+# unnest-var-recursive
+# Usage: $(call unnest-var-recursive, obj_prefix, vars, var)
+#
+# Unnest @var by including subdir Makefile.objs, while protect others in @vars
+# unchanged.
+#
+# @obj_prefix is the starting point of object path prefix.
+#
+define unnest-var-recursive
+ $(eval dirs := $(sort $(filter %/,$($3))))
+ $(eval $3 := $(filter-out %/,$($3)))
+ $(foreach d,$(dirs:%/=%),
+ $(call save-vars,$2)
+ $(eval obj := $(if $1,$1/)$d)
+ $(eval -include $(SRC_PATH)/$d/Makefile.objs)
+ $(call fix-paths,$(if $1,$1/)$d/,$d/,$2)
+ $(call load-vars,$2,$3)
+ $(call unnest-var-recursive,$1,$2,$3))
endef
+# unnest-vars
+# Usage: $(call unnest-vars, obj_prefix, vars)
+#
+# @obj_prefix: object path prefix, can be empty, or '..', etc. Don't include
+# ending '/'.
+#
+# @vars: the list of variable names to unnest.
+#
+# This macro will scan subdirectories's Makefile.objs, include them, to build
+# up each variable listed in @vars.
+#
+# Per object and per module cflags and libs are saved with relative path fixed
+# as well, those variables include -libs, -cflags and -objs. Items in -objs are
+# also fixed to relative path against SRC_PATH plus the prefix @obj_prefix.
+#
+# All nested variables postfixed by -m in names are treated as DSO variables,
+# and will be built as modules, if enabled.
+#
+# A simple example of the unnest:
+#
+# obj_prefix = ..
+# vars = hot cold
+# hot = fire.o sun.o season/
+# cold = snow.o water/ season/
+#
+# Unnest through a faked source directory structure:
+#
+# SRC_PATH
+# ├── water
+# │ └── Makefile.objs──────────────────┐
+# │ │ hot += steam.o │
+# │ │ cold += ice.mo │
+# │ │ ice.mo-libs := -licemaker │
+# │ │ ice.mo-objs := ice1.o ice2.o │
+# │ └──────────────────────────────┘
+# │
+# └── season
+# └── Makefile.objs──────┐
+# │ hot += summer.o │
+# │ cold += winter.o │
+# └──────────────────┘
+#
+# In the end, the result will be:
+#
+# hot = ../fire.o ../sun.o ../season/summer.o
+# cold = ../snow.o ../water/ice.mo ../season/winter.o
+# ../water/ice.mo-libs = -licemaker
+# ../water/ice.mo-objs = ../water/ice1.o ../water/ice2.o
+#
+# Note that 'hot' didn't include 'season/' in the input, so 'summer.o' is not
+# included.
+#
define unnest-vars
-$(eval obj := $1)
-$(eval nested-vars := $2)
-$(foreach v,$(nested-vars),$(call fix-obj-vars,$v,$(obj)))
-$(eval old-nested-dirs := )
-$(call unnest-vars-1)
-$(if $1,$(foreach v,$(nested-vars),$(eval \
- $v := $(addprefix $1/,$($v)))))
-$(foreach var,$(nested-vars),$(eval $(var) := $(filter-out %/, $($(var)))))
-$(shell mkdir -p $(sort $(foreach var,$(nested-vars),$(dir $($(var))))))
-$(foreach var,$(nested-vars), $(eval \
- -include $(addsuffix *.d, $(sort $(dir $($(var)))))))
-$(foreach v,$(filter %-m,$(nested-vars)), \
- $(call process-modules,$v))
+ # In the case of target build (i.e. $1 == ..), fix path for top level
+ # Makefile.objs objects
+ $(if $1,$(call fix-paths,$1/,,$2))
+
+ # Descend and include every subdir Makefile.objs
+ $(foreach v, $2, $(call unnest-var-recursive,$1,$2,$v))
+
+ $(foreach v,$(filter %-m,$2),
+ # All .o found in *-m variables are single object modules, create .mo
+ # for them
+ $(foreach o,$(filter %.o,$($v)),
+ $(eval $(o:%.o=%.mo)-objs := $o))
+ # Now unify .o in -m variable to .mo
+ $(eval $v := $($v:%.o=%.mo))
+
+ $(eval modules: $($v:%.mo=%$(DSOSUF)))
+ $(eval modules-m += $($v:%.mo=%$(DSOSUF)))
+
+ # For non-module build, add -m to -y
+ $(if $(CONFIG_MODULES),,$(eval $(patsubst %-m,%-y,$v) += $($v))))
+
+ # .mo's are .PHONY targets
+ $(eval .PHONY: $(modules-m))
+ $(eval $(modules-m): module-common.o)
+
+ # Post-process all the unnested vars
+ $(foreach v,$2,
+ $(foreach o, $(filter %.mo,$($v)),
+ # Find all the .mo objects in variables and add dependency rules
+ # according to .mo-objs. Report error if not set
+ $(if $($o-objs),
+ $(eval $o: $($o-objs)),
+ $(error $o added in $v but $o-objs is not set))
+ # Pass the .mo-cflags along to member objects
+ $(if $($o-cflags),
+ $(foreach p,$($o-objs),
+ $(eval $p-cflags := $($o-cflags)))))
+ $(shell mkdir -p ./ $(sort $(dir $($v))))
+ # Include all the .d files
+ $(eval -include $(addsuffix *.d, $(sort $(dir $($v)))))
+ $(eval $v := $(filter-out %/,$($v))))
endef