Re: [PATCH v2 20/20] arm64: vdso32: Enable Clang Compilation
From: Nathan Chancellor <hidden>
Date: 2020-03-10 01:40:44
Also in:
linux-arch, linux-mips, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
On Fri, Mar 06, 2020 at 01:32:42PM +0000, Vincenzo Frascino wrote:
quoted hunk ↗ jump to hunk
Enable Clang Compilation for the vdso32 library. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> --- arch/arm64/kernel/vdso32/Makefile | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index 04df57b43cb1..650cfc5757eb 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile@@ -10,7 +10,18 @@ include $(srctree)/lib/vdso/Makefile # Same as cc-*option, but using CC_COMPAT instead of CC ifeq ($(CONFIG_CC_IS_CLANG), y) -CC_COMPAT ?= $(CC) +COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE_COMPAT)elfedit)) +COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..) + +CLANG_CC_COMPAT := $(CC) +CLANG_CC_COMPAT += --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) +CLANG_CC_COMPAT += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR) +CLANG_CC_COMPAT += -no-integrated-as -Qunused-arguments +ifneq ($(COMPAT_GCC_TOOLCHAIN),) +CLANG_CC_COMPAT += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN) +endif + +CC_COMPAT ?= $(CLANG_CC_COMPAT) else CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc endif-- 2.25.1
If CC_COMPAT is ever specified on the command line as clang (maybe by some unsuspecting user), we'd loose all of the above flags. Maybe it would be better to build a set of COMPAT_CLANG_FLAGS and append them to CC_COMPAT, maybe like below? Regardless, the current approach works in my testing with clang 9.0.1 and master (clang 11.0.0). This patch specifically is: Reviewed-by: Nathan Chancellor <redacted> Tested-by: Nathan Chancellor <redacted> # build ==================================================================================
diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
index 650cfc5757eb..df5145fab287 100644
--- a/arch/arm64/kernel/vdso32/Makefile
+++ b/arch/arm64/kernel/vdso32/Makefile@@ -13,15 +13,16 @@ ifeq ($(CONFIG_CC_IS_CLANG), y) COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE_COMPAT)elfedit)) COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..) -CLANG_CC_COMPAT := $(CC) -CLANG_CC_COMPAT += --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) -CLANG_CC_COMPAT += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR) -CLANG_CC_COMPAT += -no-integrated-as -Qunused-arguments +COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%)) +COMPAT_CLANG_FLAGS += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR) +COMPAT_CLANG_FLAGS += -no-integrated-as -Qunused-arguments ifneq ($(COMPAT_GCC_TOOLCHAIN),) -CLANG_CC_COMPAT += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN) +COMPAT_CLANG_FLAGS += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN) endif -CC_COMPAT ?= $(CLANG_CC_COMPAT) +CC_COMPAT ?= $(CC) +CC_COMPAT += $(COMPAT_CLANG_FLAGS) + else CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc endif
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