[Lldb-commits] [lldb][PATCH] Clear thread unwinder when stack is reset

[Kaylor, Andrew]

In debugging a problem with expression evaluation after an inferior function call, I tracked it back to the Thread object's m_unwinder_ap member not being cleared when the Thread state was restored from a checkpoint.  I was able to fix the problem by inserting a call to Unwind::Clear in the Thread::ResetFrameZeroRegisters function.  I thought that it might make sense to clear the unwinder every time the thread's stack was cleared (i.e. from Thread::ClearStackFrames), but I wasn't sure how that is used and whether it always indicates an actual stack change that the unwinder needs to know about.

The problem in question showed up in the BasicExprCommandsTestCase.test_many_expr_commands test on x86_64 Linux.

I'm attaching two patches, one with each implementation, though only one is needed.  Can someone offer some guidance as to which approach is preferred?

Thanks,
Andy

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