[ALPS05556626] kernel: introduce LLVM=1 and gas toolchain to kenv.mk

Linux can now be built with LLVM=1, all necessary llvm params
such as CC, LD, OBJCOPY, and NM will be set correctly.

Introduce LLVM=1 to kenv.mk and drop legacy approach.
To make it work, we have to also change build.config.mtk* files.

With commit commit 2c71673913c12528c77bd0f75ce2c6adc9ac5059
("Revert "ANDROID: Kbuild, LLVMLinux: allow overriding clang target triple""),
we must not use "CLANG_TRIPLE" in build commands, otherwise well
have boot failures.

MTK-Commit-Id: 52ced0a041efb0231efb134de7f821b3f678ced8

Change-Id: I76f2ec556e14d8ed28a89bc13e3b551fda625037
CR-Id: ALPS05556626
Feature: [Module]Kernel Maintenance
Signed-off-by: Miles Chen <[email protected]>

build.config.mtk.aarch64

@@ -1,12 +1,18 @@
 ARCH=arm64
-CLANG_TRIPLE=aarch64-linux-gnu-
-CROSS_COMPILE=aarch64-linux-androidkernel-
-CC=clang
-LD=ld.lld
+CROSS_COMPILE=aarch64-linux-gnu-
+LLVM=1
+LLVM_IAS=1
 LD_LIBRARY_PATH=prebuilts/clang/host/linux-x86/clang-r383902/lib64:$$LD_LIBRARY_PATH
-NM=llvm-nm
-OBJCOPY=llvm-objcopy
 # DEFCONFIG=defconfig
 KERNEL_DIR=kernel-4.19
 CLANG_PREBUILT_BIN=prebuilts/clang/host/linux-x86/clang-r383902/bin
-LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN=prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin
+# for check scripts
+CC=clang
+LD=ld.lld
+AR=llvm-ar
+NM=llvm-nm
+OBJCOPY=llvm-objcopy
+OBJDUMP=llvm-objdump
+READELF=llvm-readelf
+OBJSIZE=llvm-size
+STRIP=llvm-strip

build.config.mtk.aarch64.kasan

@@ -1,12 +1,18 @@
 ARCH=arm64
-CLANG_TRIPLE=aarch64-linux-gnu-
-CROSS_COMPILE=aarch64-linux-androidkernel-
-CC=clang
-LD=ld.lld
+CROSS_COMPILE=aarch64-linux-gnu-
+LLVM=1
+LLVM_IAS=1
 LD_LIBRARY_PATH=prebuilts/clang/host/linux-x86/clang-r383902/lib64:$$LD_LIBRARY_PATH
-NM=llvm-nm
-OBJCOPY=llvm-objcopy
 # DEFCONFIG=defconfig
 KERNEL_DIR=kernel-4.19
 CLANG_PREBUILT_BIN=prebuilts/clang/host/linux-x86/clang-r383902/bin
-LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN=prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin
+# for check scripts
+CC=clang
+LD=ld.lld
+AR=llvm-ar
+NM=llvm-nm
+OBJCOPY=llvm-objcopy
+OBJDUMP=llvm-objdump
+READELF=llvm-readelf
+OBJSIZE=llvm-size
+STRIP=llvm-strip

build.config.mtk.aarch64.ubsan

@@ -1,12 +1,18 @@
 ARCH=arm64
-CLANG_TRIPLE=aarch64-linux-gnu-
-CROSS_COMPILE=aarch64-linux-androidkernel-
-CC=clang
-LD=ld.lld
+CROSS_COMPILE=aarch64-linux-gnu-
+LLVM=1
+LLVM_IAS=1
 LD_LIBRARY_PATH=prebuilts/clang/host/linux-x86/clang-r383902/lib64:$$LD_LIBRARY_PATH
-NM=llvm-nm
-OBJCOPY=llvm-objcopy
 # DEFCONFIG=defconfig
 KERNEL_DIR=kernel-4.19
 CLANG_PREBUILT_BIN=prebuilts/clang/host/linux-x86/clang-r383902/bin
-LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN=prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin
+# for check scripts
+CC=clang
+LD=ld.lld
+AR=llvm-ar
+NM=llvm-nm
+OBJCOPY=llvm-objcopy
+OBJDUMP=llvm-objdump
+READELF=llvm-readelf
+OBJSIZE=llvm-size
+STRIP=llvm-strip

build.config.mtk.arm

@@ -1,9 +1,19 @@
 ARCH=arm
-CLANG_TRIPLE=arm-linux-gnueabi-
-CROSS_COMPILE=arm-linux-androidkernel-
-CC=clang
-LD=ld.lld
+
+CROSS_COMPILE=arm-linux-gnueabi-
+LLVM=1
+
 # DEFCONFIG=defconfig
 KERNEL_DIR=kernel-4.19
 CLANG_PREBUILT_BIN=prebuilts/clang/host/linux-x86/clang-r383902/bin
-LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN=prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.9/bin
+LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN=prebuilts/gas/linux-x86
+# for check scripts
+CC=clang
+LD=ld.lld
+AR=llvm-ar
+NM=llvm-nm
+OBJCOPY=llvm-objcopy
+OBJDUMP=llvm-objdump
+READELF=llvm-readelf
+OBJSIZE=llvm-size
+STRIP=llvm-strip

kenv.mk

@@ -38,38 +38,37 @@ ifneq ($(strip $(TARGET_NO_KERNEL)),true)
   endif
 
   ARGS := CROSS_COMPILE=$(CROSS_COMPILE)
-  ifneq ($(CLANG_TRIPLE),)
-    ARGS += CLANG_TRIPLE=$(CLANG_TRIPLE)
-  endif
-  ifneq ($(LD),)
-    ARGS += LD=$(LD)
-  endif
-  ifneq ($(LD_LIBRARY_PATH),)
-    ARGS += LD_LIBRARY_PATH=$(KERNEL_ROOT_DIR)/$(LD_LIBRARY_PATH)
-  endif
-  ifneq ($(NM),)
-    ARGS += NM=$(NM)
-  endif
-  ifneq ($(OBJCOPY),)
-    ARGS += OBJCOPY=$(OBJCOPY)
-  endif
-  ifeq ("$(CC)", "gcc")
-    CC :=
-  endif
-
-  ifneq ($(filter-out false,$(USE_CCACHE)),)
-    CCACHE_EXEC ?= /usr/bin/ccache
-    CCACHE_EXEC := $(abspath $(wildcard $(CCACHE_EXEC)))
-  else
-    CCACHE_EXEC :=
-  endif
-  ifneq ($(CCACHE_EXEC),)
-    ifneq ($(CC),)
-      ARGS += CCACHE_CPP2=yes CC='$(CCACHE_EXEC) $(CC)'
+  ifneq ($(LLVM),)
+    ARGS += LLVM=1
+    ifneq ($(filter-out false,$(USE_CCACHE)),)
+      CCACHE_EXEC ?= /usr/bin/ccache
+      CCACHE_EXEC := $(abspath $(wildcard $(CCACHE_EXEC)))
+    else
+      CCACHE_EXEC :=
     endif
-  else
-    ifneq ($(CC),)
-      ARGS += CC=$(CC)
+    ifneq ($(CCACHE_EXEC),)
+      ARGS += CCACHE_CPP2=yes CC='$(CCACHE_EXEC) clang'
+    else
+      ARGS += CC=clang
+    endif
+    ifneq ($(LLVM_IAS),)
+      ARGS += LLVM_IAS=$(LLVM_IAS)
+    endif
+    ifeq ($(HOSTCC),)
+      ifneq ($(CC),)
+        ARGS += HOSTCC=$(CC)
+      endif
+    else
+      ARGS += HOSTCC=$(HOSTCC)
+    endif
+    ifneq ($(LD),)
+      ARGS += LD=$(LD) HOSTLD=$(LD)
+      ifneq ($(suffix $(LD)),)
+        ARGS += HOSTLDFLAGS=-fuse-ld=$(subst .,,$(suffix $(LD)))
+      endif
+    endif
+    ifneq ($(LD_LIBRARY_PATH),)
+      ARGS += LD_LIBRARY_PATH=$(KERNEL_ROOT_DIR)/$(LD_LIBRARY_PATH)
     endif
   endif