Key the object cache on the sources that generate the objects - #19
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dreamsailing59-ops merged 1 commit intoAug 22, 2026
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DOLLLVM_CACHE_VERSION is a hand-edited string, so the generated-object cache only invalidates when someone remembers to bump it. It does not invalidate when the emitter changes, which is the case that matters: a stale object is a measurement of code that is no longer in the tree. Hash the sources that decide what gets emitted and fold the digest into every job key. The file list is a CONFIGURE_DEPENDS glob rather than an explicit list -- an explicit list has to be maintained, and the backend rewrite renamed most of the files one would have contained. Editing any covered file re-runs configure and changes the digest, which changes every cache key. Verified: touching src/backend/llvm/psq.cpp moved the digest from 0f6d8569 to 880db2ba across the 46 covered files, and 28/28 ctest passes with it applied. Note this branch is cut from main, which does not currently link against the official LLVM 20 Windows package; the digest was verified on a tree that also carries that link fix.
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What
DOLLLVM_CACHE_VERSIONis a hand-edited string, so the generated-object cache only invalidates when someone remembers to bump it. It does not invalidate when the emitter changes — which is the case that matters, because a stale object means measuring code that is no longer in the tree.Fix
Hash the sources that decide what gets emitted and fold the digest into every job key:
A
CONFIGURE_DEPENDSglob rather than an explicit file list, deliberately: an explicit list has to be maintained, and the recent backend rewrite renamed most of the files one would have contained. Editing any covered file re-runs configure, changes the digest, and changes every cache key.Verification
Touching
src/backend/llvm/psq.cppmoved the digest across the 46 covered files:28/28 ctest with it applied.
Note
This branch is cut from
main, which does not currently link against the official LLVM 20 Windows package (see the target-registration PR). The digest was verified on a tree that also carries that link fix.