[PATCH 1/2] Makefile: move initial clang flag handling into scripts/Makefile.clang

From: Nick Desaulniers
Date: Wed Jul 07 2021 - 18:43:20 EST


With some of the changes we'd like to make to CROSS_COMPILE, the initial
block of clang flag handling which controls things like the target triple,
whether or not to use the integrated assembler and how to find GAS,
and erroring on unknown warnings is becoming unwieldy. Move it into its
own file under scripts/.

Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
---
Changes RFC -> v1:
* Rename new file as per Nathan.

MAINTAINERS | 1 +
Makefile | 15 +--------------
scripts/Makefile.clang | 14 ++++++++++++++
3 files changed, 16 insertions(+), 14 deletions(-)
create mode 100644 scripts/Makefile.clang

diff --git a/MAINTAINERS b/MAINTAINERS
index 81e1edeceae4..9c1205c258c7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4433,6 +4433,7 @@ B: https://github.com/ClangBuiltLinux/linux/issues
C: irc://chat.freenode.net/clangbuiltlinux
F: Documentation/kbuild/llvm.rst
F: include/linux/compiler-clang.h
+F: scripts/Makefile.clang
F: scripts/clang-tools/
K: \b(?i:clang|llvm)\b

diff --git a/Makefile b/Makefile
index cbab0dc53065..010e3a4e770b 100644
--- a/Makefile
+++ b/Makefile
@@ -586,20 +586,7 @@ endif
CC_VERSION_TEXT = $(subst $(pound),,$(shell $(CC) --version 2>/dev/null | head -n 1))

ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
-ifneq ($(CROSS_COMPILE),)
-CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
-endif
-ifeq ($(LLVM_IAS),1)
-CLANG_FLAGS += -integrated-as
-else
-CLANG_FLAGS += -no-integrated-as
-GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
-CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
-endif
-CLANG_FLAGS += -Werror=unknown-warning-option
-KBUILD_CFLAGS += $(CLANG_FLAGS)
-KBUILD_AFLAGS += $(CLANG_FLAGS)
-export CLANG_FLAGS
+include $(srctree)/scripts/Makefile.clang
endif

# Include this also for config targets because some architectures need
diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang
new file mode 100644
index 000000000000..297932e973d4
--- /dev/null
+++ b/scripts/Makefile.clang
@@ -0,0 +1,14 @@
+ifneq ($(CROSS_COMPILE),)
+CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
+endif
+ifeq ($(LLVM_IAS),1)
+CLANG_FLAGS += -integrated-as
+else
+CLANG_FLAGS += -no-integrated-as
+GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
+CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
+endif
+CLANG_FLAGS += -Werror=unknown-warning-option
+KBUILD_CFLAGS += $(CLANG_FLAGS)
+KBUILD_AFLAGS += $(CLANG_FLAGS)
+export CLANG_FLAGS
--
2.32.0.93.g670b81a890-goog