Compile.h Error on building kernel w clang

./include/generated/compile.h:7:24: warning: missing terminating '"' character [-Winvalid-pp-token]
#define LINUX_COMPILER "Android (7284624, based on r416183b) clang version 12.0.5 (https://android.googlesource.com/toolchain/llvm-project c935d99d7cf2016289302412d708641d52d2f7ee)
                       ^
./include/generated/compile.h:8:1: error: unknown type name 'Found'

去看 error source，是在 kernel source 里：
kernel-4.19/include/generated/compile.h
在產生 compile.h 的時候...

#define LINUX_COMPILER "Android (7284624, based on r416183b) clang version 12.0.5 (https://android.googlesource.com/toolchain/llvm-project c935d99d7cf2016289302412d708641d52d2f7ee)
Found CUDA installation: /usr/local/cuda, version 11.0, LLD 12.0.5 (/buildbot/src/android/llvm-toolchain/out/llvm-project/lld c935d99d7cf2016289302412d708641d52d2f7ee)"

define 不支援斷行...

init/Makefile:

   $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@   \
    "$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)"    \
    "$(CC) $(KBUILD_CFLAGS)" "$(LD)"

然後 mkcompile_h 中：

TARGET=$1
ARCH=$2
SMP=$3
PREEMPT=$4
CC=$5
LD=$6

..

( echo /\* This file is auto generated, version $VERSION \*/
  if [ -n "$CONFIG_FLAGS" ] ; then echo "/* $CONFIG_FLAGS */"; fi

  echo \#define UTS_MACHINE \"$ARCH\"

  echo \#define UTS_VERSION \"`echo $UTS_VERSION | $UTS_TRUNCATE`\"

  echo \#define LINUX_COMPILE_BY \"`echo $LINUX_COMPILE_BY | $UTS_TRUNCATE`\"
  echo \#define LINUX_COMPILE_HOST \"`echo $LINUX_COMPILE_HOST | $UTS_TRUNCATE`\"

  CC_VERSION=$($CC -v 2>&1 | grep ' version ' | sed 's/[[:space:]]*$//')
  LD_VERSION=$($LD -v | head -n1 | sed 's/(compatible with [^)]*)//' \
              | sed 's/[[:space:]]*$//')
  printf '#define LINUX_COMPILER "%s"\n' "$CC_VERSION, $LD_VERSION"
) > .tmpcompile

這個script 在 kernel 5.X 之後由 Kconfig 取代了。

測試一下 CC_VERSION 的產生： $CC -v
Android 這邊是用 prebuild 內的 clang。
執行結果：

prebuilts/clang/host/linux-x86/clang-3289846$ bin/clang -v
Android clang version 3.8.275480  (based on LLVM 3.8.275480)
Target: x86_64-unknown-linux
Thread model: posix
InstalledDir: /home/charles-chang/Android12/prebuilts/clang/host/linux-x86/clang-3289846/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
Found CUDA installation: /usr/local/cuda, version unknown

果然出現 CUDA，因為也有 version 字樣，所以有出現在後面的 grep 結果。

所以把 grep ' version ' 改 'clang version ' 試試...
好像 OK, compile.h 有問題的部份變成...

#define LINUX_COMPILER "Android (7284624, based on r416183b) clang version 12.0.5 (https://android.googlesource.com/toolchain/llvm-project c935d99d7cf2016289302412d708641d52d2f7ee), LLD 12.0.5 (/buildbot/src/android/llvm-toolchain/out/llvm-project/lld c935d99d7cf2016289302412d708641d52d2f7ee)"

--- 但是要是不是用 clang 就會 fail 吧...
改只取line 1 好了...

kernel-4.19$ git diff
diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h
index 19de4cdef1ec..b1e1d7540b9c 100755
--- a/scripts/mkcompile_h
+++ b/scripts/mkcompile_h
@@ -73,7 +73,7 @@ UTS_TRUNCATE="cut -b -$UTS_LEN"
   echo \#define LINUX_COMPILE_BY \"`echo $LINUX_COMPILE_BY | $UTS_TRUNCATE`\"
   echo \#define LINUX_COMPILE_HOST \"`echo $LINUX_COMPILE_HOST | $UTS_TRUNCATE`\"
 
-  CC_VERSION=$($CC -v 2>&1 | grep ' version ' | sed 's/[[:space:]]*$//')
+  CC_VERSION=$($CC -v 2>&1 | grep ' version ' | sed 's/[[:space:]]*$//' | head -n 1)
   LD_VERSION=$($LD -v | head -n1 | sed 's/(compatible with [^)]*)//' \
                      | sed 's/[[:space:]]*$//')
   printf '#define LINUX_COMPILER "%s"\n' "$CC_VERSION, $LD_VERSION"