[cfe-dev] speed up debugging a static analysis checker?

Lou Wynn via cfe-dev cfe-dev at lists.llvm.org
Wed Oct 3 23:06:50 PDT 2018

I tried that git monorepo method, but got the same slowdown about 21 
seconds as before with either gold or lldb and dynamic linking. It's 
still slower with the default static linking.


On 10/03/2018 02:46 PM, George Karpenkov wrote:
> Hi Lou,
> I find it easiest to just follow the guide at
> https://llvm.org/docs/GettingStarted.html#for-developers-to-work-with-a-git-monorepo
> specify the projects you need (probably “clang;libcxx;libcxxabi”), set 
> the linker to gold and not customize anything else.
> If you do that, do you still hit the slowdown?
> George
>> On Oct 3, 2018, at 2:25 PM, Lou Wynn <lewisurn at gmail.com 
>> <mailto:lewisurn at gmail.com>> wrote:
>>>>>> (lldb) b SimpleStreamChecker.cpp:132
>>>>>> Breakpoint 1: no locations (pending).
>>>>>> WARNING: Unable to resolve breakpoint to any actual locations.
>>>>> This is also weird. If lldb replies with “Unable to resolve 
>>>>> breakpoint”, it means that, well, it could not resolve the breakpoint.
>>>>> And yet it does stop at a breakpoint (much) later on.
>>>> My build uses dynamically linked libraries, and the symbol is not 
>>>> available when the related library isn't loaded.
>>> I think that is your problem.
>> Any idea on how to fix it?
>>>> When I use the default build which uses statically linked 
>>>> libraries, it becomes much slower, with a huge clang program that 
>>>> is 1.5G without a machine target.
>>> Is 1.5GB a problem though?
>>> In my experience “gold” linker on Linux should be performant enough.
>> I'm not sure. But it takes more than 30s to hit the breakpoint with 
>> the statically linked library.

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