path: root/scripts/Makefile.lib
diff options
authorMasahiro Yamada <>2014-03-05 16:59:40 +0900
committerTom Rini <>2014-03-07 10:59:06 -0500
commit026f9cf24f3c9d30c47c42bac622a64338caf596 (patch)
tree6449f4e4401aaf4eabc558a30558539de56a3bfd /scripts/Makefile.lib
parenta0a15b441cfd5a192aacfb88a8d062d008488614 (diff)
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 (arch/*/ and board/*/ 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/ to not include Instead, add $(PLATFORM_CPPFLAGS) to asflags-y, ccflags-y, cppflags-y. - Export many variables Going forward, Kbuild will not parse files when it descends into subdirectories. If we want to set variables in and use them in subdirectories, they must be exported. This is the list of variables to get exported: PLATFORM_CPPFLAGS CPUDIR BOARDDIR OBJCOPYFLAGS LDFLAGS LDFLAGS_FINAL (used in nand_spl/board/*/*/Makefile) CONFIG_STANDALONE_LOAD_ADDR (used in examples/standalone/Makefile) SYM_PREFIX (used in examples/standalone/Makefile) RELFLAGS (used in examples/standalone/Makefile) - Delete CPPFLAGS This variable has been replaced with PLATFORM_CPPFLAGS - Copy gcclibdir from example/standalone/Makefile to arch/sparc/ The reference in CONFIG_STANDALONE_LOAD_ADDR must be resolved before it is exported. Signed-off-by: Masahiro Yamada <> Reported-by: Simon Glass <> Acked-by: Simon Glass <> Tested-by: Simon Glass <> [on Sandbox] Tested-by: Stephen Warren <> [on Tegra]
Diffstat (limited to 'scripts/Makefile.lib')
1 files changed, 3 insertions, 4 deletions
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 02b17b1057..d568fde2cc 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -101,13 +101,12 @@ basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(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)
$(ccflags-y) $(CFLAGS_$(basetarget).o)
_c_flags = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))
$(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
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