1 files changed, 46 insertions, 38 deletions

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index f01f8c072852..06c1a377c4c5 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -1,7 +1,7 @@
 ####
 # kbuild: Generic definitions
 
-# Convinient variables
+# Convenient variables
 comma   := ,
 squote  := '
 empty   :=
@@ -59,32 +59,40 @@ endef
 # output directory for tests below
 TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
 
+# try-run
+# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
+# Exit code chooses option. "$$TMP" is can be used as temporary file and
+# is automatically cleaned up.
+try-run = $(shell set -e;               \
+        TMP="$(TMPOUT).$$$$.tmp";       \
+        if ($(1)) >/dev/null 2>&1;      \
+        then echo "$(2)";               \
+        else echo "$(3)";               \
+        fi;                             \
+        rm -f "$$TMP")
+
 # as-option
-# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
+# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
 
-as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
-             -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
-             else echo "$(2)"; fi ;)
+as-option = $(call try-run,\
+        $(CC) $(CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
 
 # as-instr
-# Usage: cflags-y += $(call as-instr, instr, option1, option2)
+# Usage: cflags-y += $(call as-instr,instr,option1,option2)
 
-as-instr = $(shell if echo -e "$(1)" | \
-                      $(CC) $(AFLAGS) -c -xassembler - \
-                            -o $(TMPOUT)astest$$$$.out > /dev/null 2>&1; \
-                   then rm $(TMPOUT)astest$$$$.out; echo "$(2)"; \
-                   else echo "$(3)"; fi)
+as-instr = $(call try-run,\
+        echo -e "$(1)" | $(CC) $(AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
 
 # cc-option
-# Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
+# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
 
-cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
-             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
+cc-option = $(call try-run,\
+        $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",$(1),$(2))
 
 # cc-option-yn
-# Usage: flag := $(call cc-option-yn, -march=winchip-c6)
-cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
-                > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
+# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
+cc-option-yn = $(call try-run,\
+        $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",y,n)
 
 # cc-option-align
 # Prefix align with either -falign or -malign
@@ -92,20 +100,19 @@ cc-option-align = $(subst -functions=0,,\
         $(call cc-option,-falign-functions=0,-malign-functions=0))
 
 # cc-version
-# Usage gcc-ver := $(call cc-version, $(CC))
+# Usage gcc-ver := $(call cc-version,$(CC))
 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
 
 # cc-ifversion
 # Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
-cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
-                       echo $(3); fi;)
+cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
 
 # ld-option
 # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
-ld-option = $(shell if $(CC) $(1) -nostdlib -xc /dev/null \
-                             -o $(TMPOUT)ldtest$$$$.out > /dev/null 2>&1; \
-             then rm $(TMPOUT)ldtest$$$$.out; echo "$(1)"; \
-             else echo "$(2)"; fi)
+ld-option = $(call try-run,\
+        $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
+
+######
 
 ###
 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
@@ -113,19 +120,25 @@ ld-option = $(shell if $(CC) $(1) -nostdlib -xc /dev/null \
 # $(Q)$(MAKE) $(build)=dir
 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
 
-# Prefix -I with $(srctree) if it is not an absolute path
+# Prefix -I with $(srctree) if it is not an absolute path.
 addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
+
 # Find all -I options and call addtree
 flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 
-# If quiet is set, only print short version of command
+# echo command.
+# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
+echo-cmd = $(if $($(quiet)cmd_$(1)),\
+        echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
+
+# printing commands
 cmd = @$(echo-cmd) $(cmd_$(1))
 
-# Add $(obj)/ for paths that is not absolute
+# Add $(obj)/ for paths that are not absolute
 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 
 ###
-# if_changed      - execute command if any prerequisite is newer than 
+# if_changed      - execute command if any prerequisite is newer than
 #                   target, or command line has changed
 # if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 #                   including used config symbols
@@ -133,16 +146,12 @@ objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 # See Documentation/kbuild/makefiles.txt for more info
 
 ifneq ($(KBUILD_NOCMDDEP),1)
-# Check if both arguments has same arguments. Result in empty string if equal
+# Check if both arguments has same arguments. Result is empty string if equal.
 # User may override this check using make KBUILD_NOCMDDEP=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)))$(echo-why)';)
-
 # >'< substitution is for echo to work,
 # >$< substitution to preserve $ when reloading .cmd file
 # note: when using inline perl scripts [perl -e '...$$t=1;...']
@@ -153,15 +162,14 @@ make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
 # 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
+# Execute command if command has changed or prerequisite(s) are updated.
 #
 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
+# Execute the command and also postprocess generated .d dependencies file.
 if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
         @set -e;                                                             \
         $(echo-cmd) $(cmd_$(1));                                             \
@@ -170,8 +178,8 @@ if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
         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)
+# Will check if $(cmd_foo) or any of the prerequisites changed,
+# and if so will execute $(rule_foo).
 if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
         @set -e;                                                             \
         $(rule_$(1)))