In builds of linux-firmware when TOOLCHAIN=clang, the package_qa is non-deterministic. The ldflags test in package_qa_hash_style() uses elf.run_objdump() which calls ${OBJDUMP}, but notably just returns the empty string if objdump fails with an error. With TOOLCHAIN=clang, OBJDUMP is "${HOST_PREFIX}llvm-objdump". The package_qa task depends on POPULATESYSROOTDEPS which for target builds is "virtual/cross-binutils:do_populate_sysroot", which is not where llvm-objdump is. Several issues jump out at me: 1) run_objdump() should likely _at least_ warn if it fails, if not fail 2) clang.bbclass should extend POPULATESYSROOTDEPS to include llvm-native.
3) allarch clears POPULATESYSROOTDEPS
I wish bugzilla let you edit comments. Re (3) we can't not unset POPULATESYSROOTDEPS because otherwise it depends on cross-binutils-allarch, which doesn't exist. A horrible but interesting solution would be to use binutils-native as a provider of cross-binutils-allarch. Another approach might be to actually build both binutils-native (strip, etc) and binutils-cross (ld and anything else that needs to know about sysroots) which means we can be more specific about dependencies.