Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

Pull kbuild updates from Michal Marek:

 - new option CONFIG_TRIM_UNUSED_KSYMS which does a two-pass build and
   unexports symbols which are not used in the current config [Nicolas
   Pitre]

 - several kbuild rule cleanups [Masahiro Yamada]

 - warning option adjustments for gcov etc [Arnd Bergmann]

 - a few more small fixes

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (31 commits)
  kbuild: move -Wunused-const-variable to W=1 warning level
  kbuild: fix if_change and friends to consider argument order
  kbuild: fix adjust_autoksyms.sh for modules that need only one symbol
  kbuild: fix ksym_dep_filter when multiple EXPORT_SYMBOL() on the same line
  gcov: disable -Wmaybe-uninitialized warning
  gcov: disable tree-loop-im to reduce stack usage
  gcov: disable for COMPILE_TEST
  Kbuild: disable 'maybe-uninitialized' warning for CONFIG_PROFILE_ALL_BRANCHES
  Kbuild: change CC_OPTIMIZE_FOR_SIZE definition
  kbuild: forbid kernel directory to contain spaces and colons
  kbuild: adjust ksym_dep_filter for some cmd_* renames
  kbuild: Fix dependencies for final vmlinux link
  kbuild: better abstract vmlinux sequential prerequisites
  kbuild: fix call to adjust_autoksyms.sh when output directory specified
  kbuild: Get rid of KBUILD_STR
  kbuild: rename cmd_as_s_S to cmd_cpp_s_S
  kbuild: rename cmd_cc_i_c to cmd_cpp_i_c
  kbuild: drop redundant "PHONY += FORCE"
  kbuild: delete unnecessary "@:"
  kbuild: mark help target as PHONY
  ...

1 files changed, 47 insertions, 19 deletions

diff --git a/Makefile b/Makefile
index 0f9cb36d45c2c..9ee5863dae233 100644
--- a/Makefile
+++ b/Makefile
@@ -128,6 +128,10 @@ _all:
 # Cancel implicit rules on top Makefile
 $(CURDIR)/Makefile Makefile: ;
 
+ifneq ($(words $(subst :, ,$(CURDIR))), 1)
+  $(error main directory cannot contain spaces nor colons)
+endif
+
 ifneq ($(KBUILD_OUTPUT),)
 # Invoke a second make in the output directory, passing relevant variables
 # check that the output directory actually exists
@@ -142,7 +146,7 @@ PHONY += $(MAKECMDGOALS) sub-make
 $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
 	@:
 
-sub-make: FORCE
+sub-make:
 	$(Q)$(MAKE) -C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR) \
 	-f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS))
 
@@ -364,7 +368,7 @@ AFLAGS_MODULE   =
 LDFLAGS_MODULE  =
 CFLAGS_KERNEL	=
 AFLAGS_KERNEL	=
-CFLAGS_GCOV	= -fprofile-arcs -ftest-coverage
+CFLAGS_GCOV	= -fprofile-arcs -ftest-coverage -fno-tree-loop-im -Wno-maybe-uninitialized
 CFLAGS_KCOV	= -fsanitize-coverage=trace-pc
 
 
@@ -617,7 +621,11 @@ KBUILD_CFLAGS	+= $(call cc-option,-fno-delete-null-pointer-checks,)
 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 KBUILD_CFLAGS	+= -Os $(call cc-disable-warning,maybe-uninitialized,)
 else
-KBUILD_CFLAGS	+= -O2
+ifdef CONFIG_PROFILE_ALL_BRANCHES
+KBUILD_CFLAGS	+= -O2 $(call cc-disable-warning,maybe-uninitialized,)
+else
+KBUILD_CFLAGS   += -O2
+endif
 endif
 
 # Tell gcc to never replace conditional load with a non-conditional one
@@ -697,9 +705,10 @@ KBUILD_CFLAGS += $(call cc-option, -mno-global-merge,)
 KBUILD_CFLAGS += $(call cc-option, -fcatch-undefined-behavior)
 else
 
-# This warning generated too much noise in a regular build.
-# Use make W=1 to enable this warning (see scripts/Makefile.build)
+# These warnings generated too much noise in a regular build.
+# Use make W=1 to enable them (see scripts/Makefile.build)
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
+KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
 endif
 
 ifdef CONFIG_FRAME_POINTER
@@ -926,27 +935,41 @@ export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Doc
 
 vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN)
 
-# Final link of vmlinux
-      cmd_link-vmlinux = $(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux)
-quiet_cmd_link-vmlinux = LINK    $@
-
-# Include targets which we want to
-# execute if the rest of the kernel build went well.
-vmlinux: scripts/link-vmlinux.sh $(vmlinux-deps) FORCE
+# Include targets which we want to execute sequentially if the rest of the
+# kernel build went well. If CONFIG_TRIM_UNUSED_KSYMS is set, this might be
+# evaluated more than once.
+PHONY += vmlinux_prereq
+vmlinux_prereq: $(vmlinux-deps) FORCE
 ifdef CONFIG_HEADERS_CHECK
 	$(Q)$(MAKE) -f $(srctree)/Makefile headers_check
 endif
-ifdef CONFIG_SAMPLES
-	$(Q)$(MAKE) $(build)=samples
-endif
 ifdef CONFIG_BUILD_DOCSRC
 	$(Q)$(MAKE) $(build)=Documentation
 endif
 ifdef CONFIG_GDB_SCRIPTS
 	$(Q)ln -fsn `cd $(srctree) && /bin/pwd`/scripts/gdb/vmlinux-gdb.py
 endif
+ifdef CONFIG_TRIM_UNUSED_KSYMS
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
+	  "$(MAKE) KBUILD_MODULES=1 -f $(srctree)/Makefile vmlinux_prereq"
+endif
+
+# standalone target for easier testing
+include/generated/autoksyms.h: FORCE
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh true
+
+# Final link of vmlinux
+      cmd_link-vmlinux = $(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux)
+quiet_cmd_link-vmlinux = LINK    $@
+
+vmlinux: scripts/link-vmlinux.sh vmlinux_prereq $(vmlinux-deps) FORCE
 	+$(call if_changed,link-vmlinux)
 
+# Build samples along the rest of the kernel
+ifdef CONFIG_SAMPLES
+vmlinux-dirs += samples
+endif
+
 # The actual objects are generated when descending,
 # make sure no implicit rule kicks in
 $(sort $(vmlinux-deps)): $(vmlinux-dirs) ;
@@ -998,10 +1021,12 @@ prepare2: prepare3 outputmakefile asm-generic
 prepare1: prepare2 $(version_h) include/generated/utsrelease.h \
                    include/config/auto.conf
 	$(cmd_crmodverdir)
+	$(Q)test -e include/generated/autoksyms.h || \
+	    touch   include/generated/autoksyms.h
 
 archprepare: archheaders archscripts prepare1 scripts_basic
 
-prepare0: archprepare FORCE
+prepare0: archprepare
 	$(Q)$(MAKE) $(build)=.
 
 # All the preparing..
@@ -1061,7 +1086,7 @@ INSTALL_FW_PATH=$(INSTALL_MOD_PATH)/lib/firmware
 export INSTALL_FW_PATH
 
 PHONY += firmware_install
-firmware_install: FORCE
+firmware_install:
 	@mkdir -p $(objtree)/firmware
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_install
 
@@ -1081,7 +1106,7 @@ PHONY += archscripts
 archscripts:
 
 PHONY += __headers
-__headers: $(version_h) scripts_basic asm-generic archheaders archscripts FORCE
+__headers: $(version_h) scripts_basic asm-generic archheaders archscripts
 	$(Q)$(MAKE) $(build)=scripts build_unifdef
 
 PHONY += headers_install_all
@@ -1192,7 +1217,8 @@ else # CONFIG_MODULES
 # Modules not configured
 # ---------------------------------------------------------------------------
 
-modules modules_install: FORCE
+PHONY += modules modules_install
+modules modules_install:
 	@echo >&2
 	@echo >&2 "The present kernel configuration has modules disabled."
 	@echo >&2 "Type 'make config' and enable loadable module support."
@@ -1283,6 +1309,7 @@ boards := $(sort $(notdir $(boards)))
 board-dirs := $(dir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*/*_defconfig))
 board-dirs := $(sort $(notdir $(board-dirs:/=)))
 
+PHONY += help
 help:
 	@echo  'Cleaning targets:'
 	@echo  '  clean		  - Remove most generated files but keep the config and'
@@ -1453,6 +1480,7 @@ $(clean-dirs):
 clean:	rm-dirs := $(MODVERDIR)
 clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
 
+PHONY += help
 help:
 	@echo  '  Building external modules.'
 	@echo  '  Syntax: make -C path/to/kernel/src M=$$PWD target'