Kbuild brought about many advantages for us but a significant performance regression was reported by Simon Glass.
After some discussions and analysis, it turned out its main cause is in $(call cc-option,...).
Historically, U-Boot parses all config.mk (arch/*/config.mk and board/*/config.mk) every time descending into subdirectories. That means cc-options are evaluated over and over again.
$(call cc-option,...) is useful but costly. So we want to evaluate them only in ./Makefile and spl/Makefile and export compiler flags.
This commit changes the build system as follows:
- Modify scripts/Makefile.build to not include config.mk Instead, add $(PLATFORM_CPPFLAGS) to asflags-y, ccflags-y, cppflags-y.
- Export many variables Going forward, Kbuild will not parse config.mk files when it descends into subdirectories. If we want to set variables in config.mk and use them in subdirectories, they must be exported.
This is the list of variables to get exported: PLATFORM_CPPFLAGS CPUDIR BOARDDIR OBJCOPYFLAGS LDFLAGS LDFLAGS_FINAL (used in nand_spl/board/*/*/Makefile) CONFIG_STANDALONE_LOAD_ADDR (used in examples/standalone/Makefile) SYM_PREFIX (used in examples/standalone/Makefile) RELFLAGS (used in examples/standalone/Makefile)
- Delete CPPFLAGS This variable has been replaced with PLATFORM_CPPFLAGS
- Copy gcclibdir from example/standalone/Makefile to arch/sparc/config.mk The reference in CONFIG_STANDALONE_LOAD_ADDR must be resolved before it is exported.
Signed-off-by: Masahiro Yamada yamada.m@jp.panasonic.com Reported-by: Simon Glass sjg@chromium.org Acked-by: Simon Glass sjg@chromium.org Tested-by: Simon Glass sjg@chromium.org [on Sandbox] Tested-by: Stephen Warren swarren@nvidia.com [on Tegra] ---
Changes in v3: - Modify spl/Makefile: Move KBUILD_CFLAGS += -ffunction-sections -fdata-sections LDFLAGS_FINAL += --gc-sections after include $(TOPDIR)/config.mk because $(TOPDIR)/config.mk resets the state of LDFLAGS_FINAL. Otherwise, microblaze-generic board will be broken.
Changes in v2: None
Makefile | 7 ++++--- arch/blackfin/config.mk | 1 + arch/sparc/config.mk | 2 ++ config.mk | 28 ++++++++++++++++++++-------- examples/standalone/Makefile | 5 ++--- scripts/Makefile.build | 10 +++++----- scripts/Makefile.lib | 7 +++---- spl/Makefile | 15 +++++++-------- 8 files changed, 44 insertions(+), 31 deletions(-)
diff --git a/Makefile b/Makefile index b546d76..9e91509 100644 --- a/Makefile +++ b/Makefile @@ -358,13 +358,13 @@ UBOOTRELEASE = $(shell cat include/config/uboot.release 2> /dev/null) UBOOTVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
export VERSION PATCHLEVEL SUBLEVEL UBOOTRELEASE UBOOTVERSION -export ARCH CPU BOARD VENDOR SOC +export ARCH CPU BOARD VENDOR SOC CPUDIR BOARDDIR export CONFIG_SHELL HOSTCC HOSTCFLAGS HOSTLDFLAGS CROSS_COMPILE AS LD CC export CPP AR NM LDR STRIP OBJCOPY OBJDUMP export MAKE AWK export DTC CHECK CHECKFLAGS
-export KBUILD_CPPFLAGS NOSTDINC_FLAGS UBOOTINCLUDE +export KBUILD_CPPFLAGS NOSTDINC_FLAGS UBOOTINCLUDE OBJCOPYFLAGS LDFLAGS export KBUILD_CFLAGS KBUILD_AFLAGS
# When compiling out-of-tree modules, put MODVERDIR in the module @@ -567,7 +567,8 @@ NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) CHECKFLAGS += $(NOSTDINC_FLAGS)
# FIX ME -cpp_flags := $(KBUILD_CPPFLAGS) $(CPPFLAGS) $(UBOOTINCLUDE) $(NOSTDINC_FLAGS) +cpp_flags := $(KBUILD_CPPFLAGS) $(PLATFORM_CPPFLAGS) $(UBOOTINCLUDE) \ + $(NOSTDINC_FLAGS) c_flags := $(KBUILD_CFLAGS) $(cpp_flags)
######################################################################### diff --git a/arch/blackfin/config.mk b/arch/blackfin/config.mk index adc9712..fcaa44f 100644 --- a/arch/blackfin/config.mk +++ b/arch/blackfin/config.mk @@ -43,6 +43,7 @@ CREATE_LDR_ENV = endif
SYM_PREFIX = _ +export SYM_PREFIX
LDR_FLAGS-y := LDR_FLAGS-$(CONFIG_BFIN_BOOTROM_USES_EVT1) += -J diff --git a/arch/sparc/config.mk b/arch/sparc/config.mk index 6dbf20f..be59f58 100644 --- a/arch/sparc/config.mk +++ b/arch/sparc/config.mk @@ -9,6 +9,8 @@ ifeq ($(CROSS_COMPILE),) CROSS_COMPILE := sparc-elf- endif
+gcclibdir := $(shell dirname `$(CC) -print-libgcc-file-name`) + CONFIG_STANDALONE_LOAD_ADDR ?= 0x00000000 -L $(gcclibdir) \ -T $(srctree)/examples/standalone/sparc.lds
diff --git a/config.mk b/config.mk index af25c11..4657577 100644 --- a/config.mk +++ b/config.mk @@ -6,11 +6,18 @@ # #########################################################################
-# clean the slate ... -PLATFORM_RELFLAGS = -PLATFORM_CPPFLAGS = -PLATFORM_LDFLAGS = - +# This file is included from ./Makefile and spl/Makefile. +# Clean the state to avoid the same flags added twice. +# +# (Tegra needs different flags for SPL. +# That's the reason why this file must be included from spl/Makefile too. +# If we did not have Tegra SoCs, build system would be much simpler...) +PLATFORM_RELFLAGS := +PLATFORM_CPPFLAGS := +PLATFORM_LDFLAGS := +LDFLAGS := +LDFLAGS_FINAL := +OBJCOPYFLAGS := #########################################################################
# Some architecture config.mk files need to know what CPUDIR is set to, @@ -41,12 +48,17 @@ endif
#########################################################################
-RELFLAGS= $(PLATFORM_RELFLAGS) +RELFLAGS := $(PLATFORM_RELFLAGS)
OBJCOPYFLAGS += --gap-fill=0xff
-CPPFLAGS = $(RELFLAGS) -CPPFLAGS += -pipe $(PLATFORM_CPPFLAGS) +PLATFORM_CPPFLAGS += $(RELFLAGS) +PLATFORM_CPPFLAGS += -pipe
LDFLAGS += $(PLATFORM_LDFLAGS) LDFLAGS_FINAL += -Bstatic + +export PLATFORM_CPPFLAGS +export RELFLAGS +export LDFLAGS_FINAL +export CONFIG_STANDALONE_LOAD_ADDR diff --git a/examples/standalone/Makefile b/examples/standalone/Makefile index 5b227cd..7e0e5b7 100644 --- a/examples/standalone/Makefile +++ b/examples/standalone/Makefile @@ -44,9 +44,8 @@ gcclibdir := $(shell dirname `$(CC) -print-libgcc-file-name`) # relocatable executable. The relocation data is not needed, and # also causes the entry point of the standalone application to be # inconsistent. -ifeq ($(ARCH),powerpc) -# FIX ME -CPPFLAGS := $(filter-out $(RELFLAGS), $(CPPFLAGS)) +ifeq ($(CONFIG_PPC),y) +PLATFORM_CPPFLAGS := $(filter-out $(RELFLAGS),$(PLATFORM_CPPFLAGS)) endif
# We don't want gcc reordering functions if possible. This ensures that an diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 59361f4..36346fd 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -55,11 +55,6 @@ endif
include scripts/Kbuild.include
-# Added for U-Boot -# We must include config.mk after Kbuild.include -# so that some config.mk can use cc-option. -include config.mk - # For backward compatibility check that these variables do not change save-cflags := $(CFLAGS)
@@ -68,6 +63,11 @@ kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) include $(kbuild-file)
+# Added for U-Boot +asflags-y += $(PLATFORM_CPPFLAGS) +ccflags-y += $(PLATFORM_CPPFLAGS) +cppflags-y += $(PLATFORM_CPPFLAGS) + # If the save-* variables changed error out ifeq ($(KBUILD_NOPEDANTIC),) ifneq ("$(save-cflags)","$(CFLAGS)") diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 02b17b1..d568fde 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -101,13 +101,12 @@ basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(call name-fix,$(basetarget)))" modname_flags = $(if $(filter 1,$(words $(modname))),\ -D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")
-# U-Boot also uses $(CPPFLAGS) -orig_c_flags = $(KBUILD_CPPFLAGS) $(CPPFLAGS) $(KBUILD_CFLAGS) $(KBUILD_SUBDIR_CCFLAGS) \ +orig_c_flags = $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(KBUILD_SUBDIR_CCFLAGS) \ $(ccflags-y) $(CFLAGS_$(basetarget).o) _c_flags = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags)) -_a_flags = $(KBUILD_CPPFLAGS) $(CPPFLAGS) $(KBUILD_AFLAGS) $(KBUILD_SUBDIR_ASFLAGS) \ +_a_flags = $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(KBUILD_SUBDIR_ASFLAGS) \ $(asflags-y) $(AFLAGS_$(basetarget).o) -_cpp_flags = $(KBUILD_CPPFLAGS) $(CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F)) +_cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F))
# # Enable gcov profiling flags for a file, directory or for all files depending diff --git a/spl/Makefile b/spl/Makefile index e1a0601..bb3d349 100644 --- a/spl/Makefile +++ b/spl/Makefile @@ -29,10 +29,6 @@ ifeq ($(CONFIG_TPL_BUILD),y) KBUILD_CPPFLAGS += -DCONFIG_TPL_BUILD endif
-# Enable garbage collection of un-used sections for SPL -KBUILD_CFLAGS += -ffunction-sections -fdata-sections -LDFLAGS_FINAL += --gc-sections - ifeq ($(CONFIG_TPL_BUILD),y) export CONFIG_TPL_BUILD SPL_BIN := u-boot-tpl @@ -50,8 +46,14 @@ endif
include $(TOPDIR)/config.mk
+# Enable garbage collection of un-used sections for SPL +KBUILD_CFLAGS += -ffunction-sections -fdata-sections +LDFLAGS_FINAL += --gc-sections + # FIX ME -c_flags := $(KBUILD_CFLAGS) $(KBUILD_CPPFLAGS) $(CPPFLAGS) $(UBOOTINCLUDE) $(NOSTDINC_FLAGS) +cpp_flags := $(KBUILD_CPPFLAGS) $(PLATFORM_CPPFLAGS) $(UBOOTINCLUDE) \ + $(NOSTDINC_FLAGS) +c_flags := $(KBUILD_CFLAGS) $(cpp_flags)
# Auto-generate the spl-autoconf.mk file (which is included by all makefiles for SPL) quiet_cmd_autoconf = GEN $@ @@ -228,9 +230,6 @@ PHONY += $(u-boot-spl-dirs) $(u-boot-spl-dirs): $(Q)$(MAKE) $(build)=$@
-# FIX ME -cpp_flags := $(KBUILD_CPPFLAGS) $(CPPFLAGS) $(UBOOTINCLUDE) $(NOSTDINC_FLAGS) - quiet_cmd_cpp_lds = LDS $@ cmd_cpp_lds = $(CPP) $(cpp_flags) $(LDPPFLAGS) -ansi -D__ASSEMBLY__ \ -x assembler-with-cpp -P -o $@ $<