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template: build warning-free under clang 22 - #37
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- gen-vmlinux.sh: prepend `#pragma clang system_header` to the generated vmlinux.h. bpftool dumps the kernel's tagged anonymous members verbatim (`struct foo;` inside a union), which clang 22 reports under -Wmissing-declarations. Diagnostics only; CO-RE is untouched. - runqlat.bpf.c: replace the `#pragma unroll` log2 loop (clang 22 refuses to unroll a loop with an early exit) with the branchless binary-search log2 from libbpf-tools. Same bucketing, fixed instruction count. - Makefile: default TOOLCHAIN_TAG to v0.10.1, matching the synced vendor.
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Summary
-Wmissing-declarationswarnings from vmlinux.h. bpftool dumps the kernel's tagged anonymous members verbatim (struct slock_owned;inside a union), which clang 22 now flags.gen-vmlinux.shprepends#pragma clang system_headerto the generated header. Diagnostics only: CO-RE relocations andpreserve_access_indexare unaffected, and user headers insrc/bpf/includekeep full-Wall.loop not unrolledwarning in runqlat.bpf.c. clang 22 refuses#pragma unrollon a loop with an earlybreak. The log2 bucketing now uses the branchless binary-search log2 from libbpf-tools: samefloor(log2(delta))result, fixed instruction count, nothing for the verifier to bound.TOOLCHAIN_TAGto v0.10.1, matching the already-synced vendored toolchain (it still said v0.1, which no longer exists on the release server).Test plan
scripts/newinto a scratch dir, thenmake: both BPF units compile with the v0.10.1 clang, link intobin/probe.bpf.o, esbuild bundles.make clean-bpf && make bpfproduces zero warning lines (previously 19).