Re: [OE-core] [PATCH v2] compiler-rt: Always use clang for compiler

[Gyorgy Sarvari <skandigraun@gmail.com>]

On 7/14/25 18:59, Khem Raj wrote:
> On Mon, Jul 14, 2025 at 8:03 AM Gyorgy Sarvari <skandigraun@gmail.com> wrote:
>> I realize that this is a fairly old commit... anyway.
>>
>> During the weekend I decided to update a personal project of mine to the
>> tip of master, but after performing the main required changes, I faced
>> compiler-rt build failures, complaining about unrecognized -mcpu
>> argument during the compiler sanity check in do_configure[1].
>> Bisecting oe-core points to this commit. The project I'm using uses
>> -mcpu=cortex-a72.cortex-a53+crc+crypto (DEFAULTTUNE =
>> "cortexa72-cortexa53-crypto"), which is not accepted after this change.
>>
>> Is this a user error, and I'm supposed to change something after this
>> revision, or is this a regression?
> clang has differences in syntax for big.LITTLE arm systems sadly. In meta-clang
> we have a fix for this
> https://github.com/kraj/meta-clang/blob/master/classes/clang-legacy.bbclass#L25-L38
>
> We need to do something similar in either clang bbclass or in recipes
> using toolchain-clang
> override.

Thanks a lot. Will run some tests in the coming days, and if I don't
find any issues locally, will try to submit a patch (I think it would
make sense to put it in clang.bbclass, most likely others would stumble
upon this too over time)

>> Thanks
>>
>> [1]:
>> https://gist.github.com/OldManYellsAtCloud/1e0a931a815a054a35cf61792e529b70
>>
>> On 5/6/25 22:11, Khem Raj via lists.openembedded.org wrote:
>>> This makes it build for all architectures e.g. riscv/mips/ppc etc.
>>>
>>> Using clang-native to build all variants of recipe makes it easier to
>>> handle compiling with various distros choosing different runtimes
>>>
>>> Signed-off-by: Khem Raj <raj.khem@gmail.com>
>>> ---
>>> v2: Fix builds when using clang as default system compiler
>>>
>>>  .../recipes-devtools/clang/compiler-rt_git.bb | 29 ++++++++++++-------
>>>  1 file changed, 18 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/meta/recipes-devtools/clang/compiler-rt_git.bb b/meta/recipes-devtools/clang/compiler-rt_git.bb
>>> index 93928541273..a0f9c769a06 100644
>>> --- a/meta/recipes-devtools/clang/compiler-rt_git.bb
>>> +++ b/meta/recipes-devtools/clang/compiler-rt_git.bb
>>> @@ -32,15 +32,15 @@ DEPENDS:append:class-nativesdk = " virtual/cross-c++ clang-native clang-crosssdk
>>>  DEPENDS:append:class-native = " clang-native"
>>>
>>>  # Trick clang.bbclass into not creating circular dependencies
>>> -UNWINDLIB:class-nativesdk:toolchain-clang = "--unwindlib=libgcc"
>>> -COMPILER_RT:class-nativesdk:toolchain-clang = "-rtlib=libgcc --unwindlib=libgcc"
>>> -LIBCPLUSPLUS:class-nativesdk:toolchain-clang = "-stdlib=libstdc++"
>>> -UNWINDLIB:class-native:toolchain-clang = "--unwindlib=libgcc"
>>> -COMPILER_RT:class-native:toolchain-clang = "-rtlib=libgcc --unwindlib=libgcc"
>>> -LIBCPLUSPLUS:class-native:toolchain-clang = "-stdlib=libstdc++"
>>> -UNWINDLIB:class-target:toolchain-clang = "--unwindlib=libgcc"
>>> -COMPILER_RT:class-target:toolchain-clang = "-rtlib=libgcc --unwindlib=libgcc"
>>> -LIBCPLUSPLUS:class-target:toolchain-clang = "-stdlib=libstdc++"
>>> +UNWINDLIB:class-nativesdk = "--unwindlib=libgcc"
>>> +COMPILER_RT:class-nativesdk = "-rtlib=libgcc"
>>> +LIBCPLUSPLUS:class-nativesdk = "-stdlib=libstdc++"
>>> +UNWINDLIB:class-native = "--unwindlib=libgcc"
>>> +COMPILER_RT:class-native = "-rtlib=libgcc"
>>> +LIBCPLUSPLUS:class-native = "-stdlib=libstdc++"
>>> +UNWINDLIB:class-target = "--unwindlib=libgcc"
>>> +COMPILER_RT:class-target = "-rtlib=libgcc"
>>> +LIBCPLUSPLUS:class-target = "-stdlib=libstdc++"
>>>
>>>  PACKAGECONFIG ??= ""
>>>  PACKAGECONFIG[crt] = "-DCOMPILER_RT_BUILD_CRT:BOOL=ON,-DCOMPILER_RT_BUILD_CRT:BOOL=OFF"
>>> @@ -52,6 +52,13 @@ HF = ""
>>>  HF:class-target = "${@ bb.utils.contains('TUNE_CCARGS_MFLOAT', 'hard', 'hf', '', d)}"
>>>  HF[vardepvalue] = "${HF}"
>>>
>>> +CC = "${CCACHE}${HOST_PREFIX}clang ${HOST_CC_ARCH}${TOOLCHAIN_OPTIONS}"
>>> +CXX = "${CCACHE}${HOST_PREFIX}clang++ ${HOST_CC_ARCH}${TOOLCHAIN_OPTIONS}"
>>> +BUILD_CC = "${CCACHE}clang ${BUILD_CC_ARCH}"
>>> +BUILD_CXX = "${CCACHE}clang++ ${BUILD_CC_ARCH}"
>>> +LDFLAGS += "${COMPILER_RT} ${UNWINDLIB}"
>>> +CXXFLAGS += "${LIBCPLUSPLUS}"
>>> +
>>>  OECMAKE_TARGET_COMPILE = "compiler-rt"
>>>  OECMAKE_TARGET_INSTALL = "install-compiler-rt install-compiler-rt-headers"
>>>  OECMAKE_SOURCEPATH = "${S}/llvm"
>>> @@ -72,7 +79,7 @@ EXTRA_OECMAKE += "-DCMAKE_BUILD_TYPE=RelWithDebInfo \
>>>
>>>  EXTRA_OECMAKE:append:class-native = "\
>>>                    -DCOMPILER_RT_DEFAULT_TARGET_ARCH=${HOST_ARCH} \
>>> -                  -DCMAKE_C_COMPILER_TARGET=${HOST_ARCH} \
>>> +                  -DCMAKE_C_COMPILER_TARGET=${HOST_SYS} \
>>>  "
>>>
>>>  EXTRA_OECMAKE:append:class-target = "\
>>> @@ -89,7 +96,7 @@ EXTRA_OECMAKE:append:class-nativesdk = "\
>>>                 -DCMAKE_NM=${STAGING_BINDIR_TOOLCHAIN}/${TARGET_PREFIX}llvm-nm \
>>>                 -DLLVM_TABLEGEN=${STAGING_BINDIR_NATIVE}/llvm-tblgen \
>>>                 -DCLANG_TABLEGEN=${STAGING_BINDIR_NATIVE}/clang-tblgen \
>>> -               -DCMAKE_C_COMPILER_TARGET=${HOST_ARCH}${HOST_VENDOR}-${HOST_OS}${HF} \
>>> +               -DCMAKE_C_COMPILER_TARGET=${HOST_SYS} \
>>>  "
>>>  EXTRA_OECMAKE:append:powerpc = " -DCOMPILER_RT_DEFAULT_TARGET_ARCH=powerpc "
>>>
>>>
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