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From: Masahiro Yamada <masahiroy@kernel.org>
To: linux-kbuild@vger.kernel.org
Cc: clang-built-linux@googlegroups.com,
	Nick Desaulniers <ndesaulniers@google.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/4] kbuild: remove LLVM=1 test from HAS_LTO_CLANG
Date: Thu,  4 Mar 2021 03:33:30 +0900	[thread overview]
Message-ID: <20210303183333.46543-1-masahiroy@kernel.org> (raw)

This guarding is wrong. As Documentation/kbuild/llvm.rst notes, LLVM=1
switches the default of tools, but you can still override CC, LD, etc.
individually.

BTW, LLVM is not 1/0 flag. If LLVM is not passed in, it is empty.

Non-zero return code is all treated as failure anyway.

So, $(success,test $(LLVM) -eq 1) and $(success,test "$(LLVM)" = 1)
works equivalently in the sense that both are expanded to 'n' if LLVM
is not given. The difference is that the former internally fails due
to syntax error.

  $ test ${LLVM} -eq 1
  bash: test: -eq: unary operator expected
  $ echo $?
  2

  $ test "${LLVM}" -eq 1
  bash: test: : integer expression expected
  $ echo $?
  2

  $ test "${LLVM}" = 1
  echo $?
  1

  $ test -n "${LLVM}"
  $ echo $?
  1

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 arch/Kconfig | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 2bb30673d8e6..2af10ebe5ed0 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -632,7 +632,6 @@ config HAS_LTO_CLANG
 	def_bool y
 	# Clang >= 11: https://github.com/ClangBuiltLinux/linux/issues/510
 	depends on CC_IS_CLANG && CLANG_VERSION >= 110000 && LD_IS_LLD
-	depends on $(success,test $(LLVM) -eq 1)
 	depends on $(success,test $(LLVM_IAS) -eq 1)
 	depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
 	depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
-- 
2.27.0


             reply	other threads:[~2021-03-03 20:58 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-03 18:33 Masahiro Yamada [this message]
2021-03-03 18:33 ` [PATCH 2/4] kbuild: collect minimum tool versions into scripts/tool-version.sh Masahiro Yamada
2021-03-04  0:11   ` Nathan Chancellor
2021-03-05  6:40     ` Masahiro Yamada
2021-03-12 17:21     ` Masahiro Yamada
2021-03-04 22:10   ` Nicolas Pitre
2021-03-05  6:41     ` Masahiro Yamada
2021-03-03 18:33 ` [PATCH 3/4] kbuild: check the minimum assembler version in Kconfig Masahiro Yamada
2021-03-04  0:28   ` Nathan Chancellor
2021-03-05  1:25   ` Nick Desaulniers
2021-03-05 17:48     ` Masahiro Yamada
2021-03-07  4:42       ` Nathan Chancellor
2021-03-03 18:33 ` [PATCH 4/4] kbuild: dwarf: use AS_VERSION instead of test_dwarf5_support.sh Masahiro Yamada
2021-03-03 20:44   ` Nick Desaulniers
2021-03-12 17:18     ` Masahiro Yamada
2021-03-04  0:30   ` Nathan Chancellor
2021-03-03 20:47 ` [PATCH 1/4] kbuild: remove LLVM=1 test from HAS_LTO_CLANG Nick Desaulniers
2021-03-05  6:06   ` Masahiro Yamada
2021-03-08 19:11   ` Sami Tolvanen
2021-03-03 23:37 ` Nathan Chancellor

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