compiler-rt-sanitizers, compiler-rt: skip for armv5

$ echo 'MACHINE = "qemuarmv5"' >> conf/local.conf
$ bitbake compiler-rt compiler-rt-sanitizers
...
tmp/work-shared/llvm-project-source-20.1.2-r0/llvm-project-20.1.2.src/compiler-rt/lib/builtins/arm/sync-ops.h:22:2: error: #error DMB is only supported on ARMv6+
|    22 | #error DMB is only supported on ARMv6+
|       |  ^~~~~

Due to upstream commit [[compiler-rt][builtins] Move DMB definition
to syn-ops.h][1], compiler-rt cross-compile for ARMv5 fails.

[1] https://github.com/llvm/llvm-project/commit/1c9415806ba6d0d48a160637eea7d1b70efaae69

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
 meta/recipes-devtools/clang/compiler-rt-sanitizers_git.bb | 1 +
 meta/recipes-devtools/clang/compiler-rt_git.bb            | 2 ++
 2 files changed, 3 insertions(+)

On Fri, May 9, 2025 at 4:58 AM hongxu via lists.openembedded.org
<hongxu.jia=eng.windriver.com@lists.openembedded.org> wrote:
>
> $ echo 'MACHINE = "qemuarmv5"' >> conf/local.conf
> $ bitbake compiler-rt compiler-rt-sanitizers
> ...
> tmp/work-shared/llvm-project-source-20.1.2-r0/llvm-project-20.1.2.src/compiler-rt/lib/builtins/arm/sync-ops.h:22:2: error: #error DMB is only supported on ARMv6+
> |    22 | #error DMB is only supported on ARMv6+
> |       |  ^~~~~
>
> Due to upstream commit [[compiler-rt][builtins] Move DMB definition
> to syn-ops.h][1], compiler-rt cross-compile for ARMv5 fails.
>
> [1] https://github.com/llvm/llvm-project/commit/1c9415806ba6d0d48a160637eea7d1b70efaae69
>

while it might be fine to have it disabled for armv5, I think there is
a compilation problem we are seeing here due
to misconfiguration. qemuarmv5 is using armv5te for DEFAULTTUNE which
also shows up in -march=armv5te in
TUNE_CCARGS, compiler-rt build system skips compiling the
sync_fetch_and_* routines if its armv5te and those routines
are the only one's using DMB macro, now I wonder why compiler-rt cmake
thinks it should be compiling for armv7 as
it seems to be the case here, perhaps we are missing to feed the right
value through configure arguments to cmake.
We are passing HOST_ARCH to -DCOMPILER_RT_DEFAULT_TARGET_ARCH=${HOST_ARCH}

Perhaps it should be more qualified for qemuarmv5 case, it should be
deduced from DEFAULTTUNE can you try
building for qemuarmv5 using
-DCOMPILER_RT_DEFAULT_TARGET_ARCH="${@bb.utils.contains('TUNE_FEATURES',
'armv5 thumb dsp', 'armv5te', '${HOST_ARCH}', d)}"

if this works then we need to define it more comprehensively we will
need similar mapping for armv4t and armv6 as well.

> Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
> ---
>  meta/recipes-devtools/clang/compiler-rt-sanitizers_git.bb | 1 +
>  meta/recipes-devtools/clang/compiler-rt_git.bb            | 2 ++
>  2 files changed, 3 insertions(+)
>
> diff --git a/meta/recipes-devtools/clang/compiler-rt-sanitizers_git.bb b/meta/recipes-devtools/clang/compiler-rt-sanitizers_git.bb
> index b3c4bfcffdc..8b591b757e3 100644
> --- a/meta/recipes-devtools/clang/compiler-rt-sanitizers_git.bb
> +++ b/meta/recipes-devtools/clang/compiler-rt-sanitizers_git.bb
> @@ -129,3 +129,4 @@ COMPATIBLE_HOST:libc-musl:x86-64 = "(.*)"
>  COMPATIBLE_HOST:libc-musl:riscv64 = "(.*)"
>  COMPATIBLE_HOST:libc-musl:riscv32 = "(.*)"
>  COMPATIBLE_HOST:libc-musl = "null"
> +COMPATIBLE_HOST:armv5 = "null"
> diff --git a/meta/recipes-devtools/clang/compiler-rt_git.bb b/meta/recipes-devtools/clang/compiler-rt_git.bb
> index 93928541273..d634c148508 100644
> --- a/meta/recipes-devtools/clang/compiler-rt_git.bb
> +++ b/meta/recipes-devtools/clang/compiler-rt_git.bb
> @@ -119,3 +119,5 @@ BBCLASSEXTEND = "native nativesdk"
>  ALLOW_EMPTY:${PN} = "1"
>
>  SYSROOT_DIRS:append:class-target = " ${nonarch_libdir}"
> +
> +COMPATIBLE_HOST:armv5 = "null"
> --
> 2.34.1
>
>
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