Disable concurrent compilation to prevent dangling Module pointers#565
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0xeb wants to merge 1 commit intoroot-project:masterfrom
Open
Disable concurrent compilation to prevent dangling Module pointers#5650xeb wants to merge 1 commit intoroot-project:masterfrom
0xeb wants to merge 1 commit intoroot-project:masterfrom
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Cling uses a single LLVMContext (SingleThreadedContext) and keeps raw pointers to Modules (Transaction::m_CompiledModule) for later unloading via TransactionUnloader::unloadModule. When concurrent compilation is enabled, LLJIT sets CloneToNewContextOnEmit which clones each Module into a fresh context during materialization, destroying the original. That turns m_CompiledModule into a dangling pointer and crashes in RevertTransaction (use-after-free in the Module's function list). Fix: call Builder.setSupportConcurrentCompilation(false) in the IncrementalJIT constructor.
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Summary
Cling uses a single
LLVMContext(SingleThreadedContext) and keeps raw pointers toModules (Transaction::m_CompiledModule) for later unloading viaTransactionUnloader::unloadModule. When concurrent compilation is enabled, LLJIT setsCloneToNewContextOnEmitwhich clones eachModuleinto a fresh context during materialization, destroying the original. That turnsm_CompiledModuleinto a dangling pointer and crashes inRevertTransaction(use-after-free in the Module's function list).Fix: Call
Builder.setSupportConcurrentCompilation(false)in theIncrementalJITconstructor.Test plan
undo()/RevertTransactioncrashes with use-after-free