C++ 10.4 new 64-bit LLDB debugger has major issues

I am testing a trial version of C++ 10.4 with the new LLDB-based 64-bit debugger on Windows 10 to see how much better it is than the 10.3 debugger which didn't work very well for us. I am seeing many nice improvements, but also am experiencing two issues with the new debugger that are greatly impeding the debugging process:

1. The debugger does not catch OS exceptions such as Access Violation, even when configured to do so. It's a major pain to track down an exception in a large system running dozens of threads.

2. When I hit a breakpoint or when I step, the entire IDE freezes for 30 seconds every time execution stops and for each step! This makes stepping through a function extremely painful.

A coworker is also testing, and for him the delay is 18 seconds, still not great. The main difference between our rigs is that mine has an AMD Threadripper CPU with 32 cores (64 threads) and his is an Intel CPU with 8 cores / 16 threads. Any one else see these issues and maybe offer a solution?


  • Hi Bender17, I've just been experimenting with a test Windows VCL 64 bit project using 10.4. I don't get this problem. There is a pause when the first breakpoint is hit following starting to run the C++ app under the IDE debugger. But after this it single steps fine and it also displays the values of std::vector elements as "watches" or under "evaluate modify" which is great (and something that clang 32 and classic compilers still can't do.

    My project is very small but it does seem to work fine.. I have tried it on VCL GUI application and also a VCL console application. My PC has a four core i7 processor.

    I wonder what's special about your code to cause this problem?

  • Yes I get the same operation in 32 bit code, I believe it relates to the Welcome page issue.

    Hoping the recent Patch2 solves this problem.

    There are also QC reports of this type of problem where the debugger terminates on stepping into code on exception.