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>
This commit is contained in:
Jacob Garber 2019-10-02 18:55:23 -06:00 committed by Stefan Reinauer
parent 04540f1549
commit 5e6c30bc42
2 changed files with 14 additions and 1 deletions

View File

@ -42,6 +42,15 @@ config PAYLOAD_INFO_VERSION
help help
The version number of this payload. 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 endmenu
menu "Modules" menu "Modules"

View File

@ -76,9 +76,13 @@ ifneq ($(strip $(HAVE_DOTCONFIG)),)
include $(src)/.config include $(src)/.config
real-all: $(TARGET) real-all: $(TARGET)
ifeq ($(CONFIG_LTO),y)
CFLAGS += -flto
endif
$(TARGET): $(src)/.config $(coreinfo_obj)/config.h $(OBJS) libpayload $(TARGET): $(src)/.config $(coreinfo_obj)/config.h $(OBJS) libpayload
printf " LPCC $(subst $(CURDIR)/,,$(@)) (LINK)\n" printf " LPCC $(subst $(CURDIR)/,,$(@)) (LINK)\n"
$(LPCC) -o $@ $(OBJS) $(LPCC) $(CFLAGS) -o $@ $(OBJS)
$(OBJCOPY) --only-keep-debug $@ $(TARGET).debug $(OBJCOPY) --only-keep-debug $@ $(TARGET).debug
$(OBJCOPY) --strip-debug $@ $(OBJCOPY) --strip-debug $@
$(OBJCOPY) --add-gnu-debuglink=$(TARGET).debug $@ $(OBJCOPY) --add-gnu-debuglink=$(TARGET).debug $@