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Date:   Thu, 29 Jul 2021 09:50:38 -0700
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Subject: [PATCH v3 1/2] Makefile: move initial clang flag handling into scripts/Makefile.clang
From:   Nick Desaulniers <ndesaulniers@google.com>
To:     Masahiro Yamada <masahiroy@kernel.org>
Cc:     Miguel Ojeda <ojeda@kernel.org>, Fangrui Song <maskray@google.com>,
        Michal Marek <michal.lkml@markovi.net>,
        Arnd Bergmann <arnd@kernel.org>, linux-kernel@vger.kernel.org,
        linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Christoph Hellwig <hch@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nathan Chancellor <nathan@kernel.org>
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Precedence: bulk

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/.

Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Changes V2 -> V3:
* Pick up Nathan's RB tag.

 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
-- 
2.32.0.432.gabb21c7263-goog