kernel: Allow devices to opt-in for full LLVM build
android11-5.4 kernel can fully compile with LLVM with a few cherrypicks
from android12-5.4 and android12-5.10
Change-Id: Ib71935d284ad78f1c23d039c15bfc5e0314a19eb
diff --git a/config/BoardConfigKernel.mk b/config/BoardConfigKernel.mk
index d60297e..19e5574 100644
--- a/config/BoardConfigKernel.mk
+++ b/config/BoardConfigKernel.mk
@@ -31,6 +31,8 @@
# TARGET_KERNEL_CLANG_PATH = Clang prebuilts path, optional
#
# TARGET_KERNEL_LLVM_BINUTILS = Use LLVM binutils, defaults to true
+# TARGET_KERNEL_NO_GCC = Fully compile the kernel without GCC.
+# Defaults to false
# TARGET_KERNEL_VERSION = Reported kernel version in top level kernel
# makefile. Can be overriden in device trees
# in the event of prebuilt kernel.
@@ -71,6 +73,15 @@
KERNEL_PATCHLEVEL := $(shell grep -s "^PATCHLEVEL = " $(TARGET_KERNEL_SOURCE)/Makefile | awk '{ print $$3 }')
TARGET_KERNEL_VERSION ?= $(shell echo $(KERNEL_VERSION)"."$(KERNEL_PATCHLEVEL))
+# 5.10+ can fully compile without GCC by default
+ifneq (,$(filter 5.10, $(TARGET_KERNEL_VERSION)))
+ TARGET_KERNEL_NO_GCC ?= true
+endif
+
+ifeq ($(TARGET_KERNEL_NO_GCC), true)
+ KERNEL_NO_GCC := true
+endif
+
ifneq ($(TARGET_KERNEL_CLANG_VERSION),)
KERNEL_CLANG_VERSION := clang-$(TARGET_KERNEL_CLANG_VERSION)
else
@@ -95,8 +106,7 @@
TOOLS_PATH_OVERRIDE := \
PERL5LIB=$(BUILD_TOP)/prebuilts/tools-lineage/common/perl-base
-# 5.10+ can fully compile without gcc
-ifeq (,$(filter 5.10, $(TARGET_KERNEL_VERSION)))
+ifneq ($(KERNEL_NO_GCC), true)
GCC_PREBUILTS := $(BUILD_TOP)/prebuilts/gcc/$(HOST_PREBUILT_TAG)
# arm64 toolchain
KERNEL_TOOLCHAIN_arm64 := $(GCC_PREBUILTS)/aarch64/aarch64-linux-android-4.9/bin