Stefan Reinauer has submitted this change. ( https://review.coreboot.org/c/coreboot/+/38293 )
Change subject: coreinfo: Add support for link time optimization ......................................................................
coreinfo: Add support for link time optimization
This introduces a Kconfig option for compiling coreinfo with LTO. This option can be used independently of LTO in libpayload, though will benefit most if that is enabled as well. If both are enabled, the final size of coreinfo.elf is reduced from 95 KiB to 92 KiB.
Tested in QEMU and on Thinkpad T500.
Change-Id: I6feacdb911b52b946869bff369e03dcf72897c9f Signed-off-by: Jacob Garber jgarber1@ualberta.ca Reviewed-on: https://review.coreboot.org/c/coreboot/+/38293 Reviewed-by: Michael Niewöhner foss@mniewoehner.de Reviewed-by: Martin Roth martinroth@google.com Tested-by: build bot (Jenkins) no-reply@coreboot.org --- M payloads/coreinfo/Kconfig M payloads/coreinfo/Makefile 2 files changed, 14 insertions(+), 1 deletion(-)
Approvals: build bot (Jenkins): Verified Martin Roth: Looks good to me, approved Michael Niewöhner: Looks good to me, but someone else must approve
diff --git a/payloads/coreinfo/Kconfig b/payloads/coreinfo/Kconfig index eafb879..2c1f91c 100644 --- a/payloads/coreinfo/Kconfig +++ b/payloads/coreinfo/Kconfig @@ -42,6 +42,15 @@ help The version number of this payload.
+config LTO + bool "Use link time optimization (LTO)" + default n + help + Compile with link time optimization. This can often decrease the + final binary size, but may increase compilation time. This option + is most effective when LTO is also enabled in libpayload, which + is done separately. + endmenu
menu "Modules" diff --git a/payloads/coreinfo/Makefile b/payloads/coreinfo/Makefile index d842b46..cd58f39 100644 --- a/payloads/coreinfo/Makefile +++ b/payloads/coreinfo/Makefile @@ -76,9 +76,13 @@ include $(src)/.config real-all: $(TARGET)
+ifeq ($(CONFIG_LTO),y) +CFLAGS += -flto +endif + $(TARGET): $(src)/.config $(coreinfo_obj)/config.h $(OBJS) libpayload printf " LPCC $(subst $(CURDIR)/,,$(@)) (LINK)\n" - $(LPCC) -o $@ $(OBJS) + $(LPCC) $(CFLAGS) -o $@ $(OBJS) $(OBJCOPY) --only-keep-debug $@ $(TARGET).debug $(OBJCOPY) --strip-debug $@ $(OBJCOPY) --add-gnu-debuglink=$(TARGET).debug $@