From 026f9cf24f3c9d30c47c42bac622a64338caf596 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 5 Mar 2014 16:59:40 +0900 Subject: kbuild: improve Kbuild speed 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 Reported-by: Simon Glass Acked-by: Simon Glass Tested-by: Simon Glass [on Sandbox] Tested-by: Stephen Warren [on Tegra] --- examples/standalone/Makefile | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'examples') 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 -- cgit v1.1