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[core] Fix Declare failing to autoload symbols for static initializers - #22939
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Jul 28, 2026
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Thanks for fixing this long standing bug! I added a comment and Would like to solicit a statement by @devajithvs or @hahnjo
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Jul 28, 2026
TInterpreter::Declare of a global whose static initializer needs symbols from a not-yet-loaded library (e.g. TVectorT<float> from libMatrix) failed with "Failed to materialize symbols". It worked in 6.30 but regressed in 6.32. Declare wraps parsing in a SuspendAutoLoadingRAII to behave like a plain compiler; that is a parse-time, class/dictionary-autoloading concern. But commit e601bf8 ("Reduce symbol search only to when autoloading is enabled", first released in 6.32) gated the AutoloadLibraryGenerator ORC definition generator on IsAutoLoadingEnabled() for performance, which inadvertently coupled the two: during Declare the global's static initializer runs, the JIT needs the constructor symbol from libMatrix, and the generator bailed out because class autoloading was suspended. The generator's gate cannot be relaxed for all Static lookups: a passive address query such as TGlobal::GetAddress() also issues a Static lookup, and it must keep returning "not loaded" while autoloading is suspended (see the gGeoManager check in TClingDataMemberInfo.Offset). The distinguishing factor is that the issue's suspension is Declare-internal, not a user request. Therefore let Declare opt back into JIT symbol autoloading for exactly the window where it emits and runs code, via a dedicated TClingCallbacks::IsAutoLoadingForJITSymbols() flag the generator also honors. Passive lookups outside Declare are unaffected, so the gGeoManager semantics are preserved. Closes root-project#16601. 🤖 Done with the help of AI.
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The two failures seem unrelated to the changes proposed in this PR. |
Test Results 23 files 23 suites 3d 15h 30m 4s ⏱️ For more details on these failures, see this check. Results for commit 1fea5f1. |
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TInterpreter::Declare of a global whose static initializer needs symbols from a not-yet-loaded library (e.g. TVectorT from libMatrix) failed with "Failed to materialize symbols". It worked in 6.30 but regressed in 6.32.
Declare wraps parsing in a SuspendAutoLoadingRAII to behave like a plain compiler. That is a parse-time, class/dictionary-autoloading concern. But commit e601bf8 ("Reduce symbol search only to when autoloading is enabled", first released in 6.32) gated the AutoloadLibraryGenerator ORC definition generator on IsAutoLoadingEnabled() for performance, which inadvertently coupled the two: during Declare the global's static initializer runs, the JIT needs the constructor symbol from libMatrix, and the generator bailed out because class autoloading was suspended.
Gate the generator on the lookup kind instead: only skip the (costly) library scan for speculative DLSym probes, never for Static lookups, i.e. symbols genuinely required to link and run JITed code. This mirrors LLVM's own DynamicLibrarySearchGenerator / StaticLibraryDefinitionGenerator, which act only on Static lookups, and preserves the performance intent of the original gate.
Closes #16601.
🤖 Done with the help of AI.