CODEWITHSUNDEEP
c++macosexceptionlldb
daybreak
daybreak

Reputation: 181

lldb - breaking before C++ exception thrown

In lldb I'd like to break before C++ throws the exception, on when the actual signal is generated. I'd like to do this for any type of exception.

The following command will break on the C++ throw catcher break set -E c++

I'd like to break on the cause of the exception and ignore the C++ throw/catch as if the application was crashing. I'd also like to do this for applications without source.

Is there any lldb voodoo I can use here?

Upvotes: 1

Views: 619

Answers (1)

Jim Ingham
Jim Ingham

Reputation: 27110

I'm not entirely sure what you are asking.

Exceptions throws in C++ do two things, create the exception object, and then directly call some runtime routine (__cxa_throw on most Unixen) to implement the unwinding. The latter is the point where the exception breakpoint stops. There isn't any more preliminary than this that you could hook onto.

You could try breaking when the exception object is allocated. On OS X & Linux this is __cxa_allocate_exception, but I don't know if that will always get called or if there are alternate ways to make the exception... I don't see how you would gain much from that, however, it's just a couple of instructions later that you'll see the call to the throw method.

But maybe if you describe the problem you are actually trying to solve, we can answer more helpfully...

Upvotes: 1

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