Incremental parsing segfaults on libgit2

[intjftw]

When incremental parsing is executed on libgit2 on the server behind codecompass.net, building the project is successful, however, after a few TUs, parsing fails with the error message "LLVM error: out of memory". The error is thrown during the cleanup phase.

[mcserep]

Please provide further information on this bug:

• specify at which point of the parsing the error occurs (maybe also provide console dump);
• can the error be reproduced on your local computer?

[intjftw]

Answer to reproducing: it did not emerge on my computer so far.

[whisperity]

LLVM Error: is an unfortunate side-effect of depending on LLVM, which as a hot-headed bull registers itself as the global terminate handler... The issue is possible to not have come from LLVM. It says Out of memory when an std::bad_alloc is thrown. (For example, when developing #386 and trying buffer overflow attacks, I was also getting LLVM Error: Out of memory aborts until I have manually deleted the reparse plugin (which uses LLVM on the server side...) from the build.)

The actual output pops from here:

https://github.com/llvm/llvm-project/blob/llvmorg-7.0.0/llvm/lib/Support/ErrorHandling.cpp#L169-L174

I think you might have to either play with ulimit, or Linux Control Groups or just simply by manually tinkering the available memory of a virtual machine to get the error to pop out.

[intjftw]

Resolved in #493.