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-rw-r--r--scripts/Kbuild.include93
1 files changed, 70 insertions, 23 deletions
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index bb19c1561f1..3d523899fdc 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -8,9 +8,13 @@ empty :=
space := $(empty) $(empty)
###
+# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
+dot-target = $(dir $@).$(notdir $@)
+
+###
# The temporary file to save gcc -MD generated dependencies must not
# contain a comma
-depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
+depfile = $(subst $(comma),_,$(dot-target).d)
###
# filename of target with directory and extension stripped
@@ -119,40 +123,83 @@ objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
ifneq ($(KBUILD_NOCMDDEP),1)
# Check if both arguments has same arguments. Result in empty string if equal
# User may override this check using make KBUILD_NOCMDDEP=1
-arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
+arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
+ $(filter-out $(cmd_$@), $(cmd_$(1))) )
endif
# echo command. Short version is $(quiet) equals quiet, otherwise full command
echo-cmd = $(if $($(quiet)cmd_$(1)), \
- echo ' $(call escsq,$($(quiet)cmd_$(1)))';)
+ echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
+# >'< substitution is for echo to work,
+# >$< substitution to preserve $ when reloading .cmd file
+# note: when using inline perl scripts [perl -e '...$$t=1;...']
+# in $(cmd_xxx) double $$ your perl vars
make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
-# function to only execute the passed command if necessary
-# >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
-# note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
+# Find any prerequisites that is newer than target or that does not exist.
+# PHONY targets skipped in both cases.
+any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
+
+# Execute command if command has changed or prerequisitei(s) are updated
#
-if_changed = $(if $(strip $(filter-out $(PHONY),$?) \
- $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
- @set -e; \
- $(echo-cmd) $(cmd_$(1)); \
- echo 'cmd_$@ := $(make-cmd)' > $(@D)/.$(@F).cmd)
+if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
+ @set -e; \
+ $(echo-cmd) $(cmd_$(1)); \
+ echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
# execute the command and also postprocess generated .d dependencies
# file
-if_changed_dep = $(if $(strip $(filter-out $(PHONY),$?) \
- $(filter-out FORCE $(wildcard $^),$^) \
- $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
- @set -e; \
- $(echo-cmd) $(cmd_$(1)); \
- scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(@D)/.$(@F).tmp; \
- rm -f $(depfile); \
- mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
+if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
+ @set -e; \
+ $(echo-cmd) $(cmd_$(1)); \
+ scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
+ rm -f $(depfile); \
+ mv -f $(dot-target).tmp $(dot-target).cmd)
# Usage: $(call if_changed_rule,foo)
# will check if $(cmd_foo) changed, or any of the prequisites changed,
# and if so will execute $(rule_foo)
-if_changed_rule = $(if $(strip $(filter-out $(PHONY),$?) \
- $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\
- @set -e; \
- $(rule_$(1)))
+if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
+ @set -e; \
+ $(rule_$(1)))
+
+###
+# why - tell why a a target got build
+# enabled by make V=2
+# Output (listed in the order they are checked):
+# (1) - due to target is PHONY
+# (2) - due to target missing
+# (3) - due to: file1.h file2.h
+# (4) - due to command line change
+# (5) - due to missing .cmd file
+# (6) - due to target not in $(targets)
+# (1) PHONY targets are always build
+# (2) No target, so we better build it
+# (3) Prerequisite is newer than target
+# (4) The command line stored in the file named dir/.target.cmd
+# differed from actual command line. This happens when compiler
+# options changes
+# (5) No dir/.target.cmd file (used to store command line)
+# (6) No dir/.target.cmd file and target not listed in $(targets)
+# This is a good hint that there is a bug in the kbuild file
+ifeq ($(KBUILD_VERBOSE),2)
+why = \
+ $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
+ $(if $(wildcard $@), \
+ $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
+ $(if $(arg-check), \
+ $(if $(cmd_$@),- due to command line change, \
+ $(if $(filter $@, $(targets)), \
+ - due to missing .cmd file, \
+ - due to $(notdir $@) not in $$(targets) \
+ ) \
+ ) \
+ ) \
+ ), \
+ - due to target missing \
+ ) \
+ )
+
+echo-why = $(call escsq, $(strip $(why)))
+endif