From 4c451dba25d2829a6a0c532196cce83e2e65b47e Mon Sep 17 00:00:00 2001 From: Greg Hackmann Date: Tue, 25 Oct 2016 13:59:59 -0700 Subject: [PATCH] ANDROID: Kbuild, LLVMLinux: allow overriding clang target triple Android has an unusual setup where the kernel needs to target [arch]-linux-gnu to avoid Android userspace-specific flags and optimizations, but AOSP doesn't ship a matching binutils. Add a new variable CLANG_TRIPLE which can override the "-target" triple used to compile the kernel, while using a different CROSS_COMPILE to pick the binutils/gcc installation. For Android you'd do something like: export CLANG_TRIPLE=aarch64-linux-gnu- export CROSS_COMPILE=aarch64-linux-android- If you don't need something like this, leave CLANG_TRIPLE unset and it will default to CROSS_COMPILE. Change-Id: I85d63599c6ab8ed458071cdf9197d85b1f7f150b Signed-off-by: Greg Hackmann [astrachan: Added a script to check for incorrectly falling back to the default when CLANG_TRIPLE is unset] Bug: 118439987 Bug: 120440614 Test: make CLANG_TRIPLE=x86_64-linux-gnu CC=clang Signed-off-by: Alistair Strachan --- Makefile | 6 +++++- scripts/clang-android.sh | 4 ++++ 2 files changed, 9 insertions(+), 1 deletion(-) create mode 100755 scripts/clang-android.sh diff --git a/Makefile b/Makefile index f6159092ac79..2e4da12544f7 100644 --- a/Makefile +++ b/Makefile @@ -482,7 +482,11 @@ endif ifeq ($(cc-name),clang) ifneq ($(CROSS_COMPILE),) -CLANG_TARGET := --target=$(notdir $(CROSS_COMPILE:%-=%)) +CLANG_TRIPLE ?= $(CROSS_COMPILE) +CLANG_TARGET := --target=$(notdir $(CLANG_TRIPLE:%-=%)) +ifeq ($(shell $(srctree)/scripts/clang-android.sh $(CC) $(CLANG_TARGET)), y) +$(error "Clang with Android --target detected. Did you specify CLANG_TRIPLE?") +endif GCC_TOOLCHAIN_DIR := $(dir $(shell which $(LD))) CLANG_PREFIX := --prefix=$(GCC_TOOLCHAIN_DIR) GCC_TOOLCHAIN := $(realpath $(GCC_TOOLCHAIN_DIR)/..) diff --git a/scripts/clang-android.sh b/scripts/clang-android.sh new file mode 100755 index 000000000000..9186c4f48576 --- /dev/null +++ b/scripts/clang-android.sh @@ -0,0 +1,4 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +$* -dM -E - &1 | grep -q __ANDROID__ && echo "y"