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From:   Tor Vic <torvic9@mailbox.org>
Subject: [PATCH 1/1] Makefile: Pass -warn-stack-size only on LLD < 13.0.0
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        masahiroy@kernel.org, Nathan Chancellor <nathan@kernel.org>,
        "ndesaulniers@google.com" <ndesaulniers@google.com>,
        keescook@chromium.org
Cc:     "clang-built-linux@googlegroups.com" 
        <clang-built-linux@googlegroups.com>, linux-kbuild@vger.kernel.org
Message-ID: <7631bab7-a8ab-f884-ab54-f4198976125c@mailbox.org>
Date:   Sun, 13 Jun 2021 13:07:49 +0000
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Since LLVM commit fc018eb, the '-warn-stack-size' flag has been dropped
[1], leading to the following error message when building with Clang-13
and LLD-13:

    ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
    '-warn-stack-size=2048'.  Try: 'ld.lld --help'
    ld.lld: Did you mean '--asan-stack=2048'?

In the same way as with commit 2398ce80152a ("x86, lto: Pass
-stack-alignment only on LLD < 13.0.0") , make '-warn-stack-size'
conditional on LLD < 13.0.0.

[1] https://reviews.llvm.org/D103928

Fixes: 24845dcb170e ("Makefile: LTO: have linker check -Wframe-larger-than")
Cc: stable@vger.kernel.org
Link: https://github.com/ClangBuiltLinux/linux/issues/1377
Signed-off-by: Tor Vic <torvic9@mailbox.org>
---
 Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 144d4f8b7eb3..51a1b6b2c2ab 100644
--- a/Makefile
+++ b/Makefile
@@ -929,11 +929,14 @@ CC_FLAGS_LTO	+= -fvisibility=hidden
 # Limit inlining across translation units to reduce binary size
 KBUILD_LDFLAGS += -mllvm -import-instr-limit=5

-# Check for frame size exceeding threshold during prolog/epilog insertion.
+# Check for frame size exceeding threshold during prolog/epilog insertion
+# when using lld < 13.0.0.
 ifneq ($(CONFIG_FRAME_WARN),0)
+ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
 KBUILD_LDFLAGS	+= -plugin-opt=-warn-stack-size=$(CONFIG_FRAME_WARN)
 endif
 endif
+endif

 ifdef CONFIG_LTO
 KBUILD_CFLAGS	+= -fno-lto $(CC_FLAGS_LTO)
-- 
2.32.0