MPPassManager::addLowerLevelRequiredPass may crash

[llvmbot]

Bugzilla Link	10684
Resolution	FIXED
Resolved on	Oct 10, 2011 11:19
Version	trunk
OS	Windows XP
Reporter	LLVM Bugzilla Contributor

Extended Description

the call 'FPP->add' in line 1635 (revision 137072 of lib/VMCore/PassManager.cpp) may destroy the 'RequiredPass' if such a Pass is already scheduled. This results in a dangling pointer of 'RequiredPass' which is added to the LU container in line 1639. Finally this leads to a core dump.

[llvmbot]

The cause of this crash is somewhere in Version llvm 2.8. In the trunk it might already be fixed.
In collectRequiredAnalysis transitive and not transitive passes are added to the vector 'RP_NotAvail'. Since AnalysisUsage::addRequiredTransitive adds a Pass to both it will be in the container 'RP_NotAvail' twice. This leads to the crash described above.

[llvmbot]

In lib/VMCore/Pass.cpp (revision 115703) addRequiredTransitiveID adds an ID in the container 'Required' and the container 'RequiredTransitive'.

This may lead to 'lib/VMCore/PassManager.cpp' a doubled entry in 'RP_NotAvail' in method PMDataManager::collectRequiredAnalysis and then to the described crash.

[llvmbot]

I believe this was fixed by r139642.