kernel: Implement build time LTO choice
Change-Id: I898eb50fadb6bde5beebf46f443c5de7e6acc907
diff --git a/build/tasks/kernel.mk b/build/tasks/kernel.mk
index a4bd140..88215cb 100644
--- a/build/tasks/kernel.mk
+++ b/build/tasks/kernel.mk
@@ -55,6 +55,8 @@
# aarch64-linux-gnu- for arm64
# x86_64-linux-gnu- for x86
#
+# KERNEL_LTO = Optional, force LTO to none / thin / full
+#
# NEED_KERNEL_MODULE_ROOT = Optional, if true, install kernel
# modules in root instead of vendor
# NEED_KERNEL_MODULE_SYSTEM = Optional, if true, install kernel
@@ -275,6 +277,31 @@
# $(2): The defconfig to process (just the filename, no need for full path to file)
define make-kernel-config
$(call internal-make-kernel-target,$(1),VARIANT_DEFCONFIG=$(VARIANT_DEFCONFIG) SELINUX_DEFCONFIG=$(SELINUX_DEFCONFIG) $(2))
+ $(hide) if [ "$(KERNEL_LTO)" = "none" ]; then \
+ $(KERNEL_SRC)/scripts/config --file $(1)/.config \
+ -d LTO_CLANG \
+ -e LTO_NONE \
+ -d LTO_CLANG_THIN \
+ -d LTO_CLANG_FULL \
+ -d THINLTO; \
+ $(call make-kernel-target,olddefconfig); \
+ elif [ "$(KERNEL_LTO)" = "thin" ]; then \
+ $(KERNEL_SRC)/scripts/config --file $(1)/.config \
+ -e LTO_CLANG \
+ -d LTO_NONE \
+ -e LTO_CLANG_THIN \
+ -d LTO_CLANG_FULL \
+ -e THINLTO; \
+ $(call make-kernel-target,olddefconfig); \
+ elif [ "$(KERNEL_LTO)" = "full" ]; then \
+ $(KERNEL_SRC)/scripts/config --file $(1)/.config \
+ -e LTO_CLANG \
+ -d LTO_NONE \
+ -d LTO_CLANG_THIN \
+ -e LTO_CLANG_FULL \
+ -d THINLTO; \
+ $(call make-kernel-target,olddefconfig); \
+ fi
$(hide) if [ ! -z "$(KERNEL_CONFIG_OVERRIDE)" ]; then \
echo "Overriding kernel config with '$(KERNEL_CONFIG_OVERRIDE)'"; \
echo $(KERNEL_CONFIG_OVERRIDE) >> $(1)/.config; \