[cfe-dev] [clangd] Worker threads stack size

[Eric Liu via cfe-dev]

+clangd-dev at lists.llvm.org <clangd-dev at lists.llvm.org> +Ilya Biryukov
<ibiryukov at google.com>

On Fri, Aug 17, 2018 at 2:41 PM Dmitry.Kozhevnikov at jetbrains.com via
cfe-dev <cfe-dev at lists.llvm.org> wrote:

> Hello!
>
> clangd uses std::thread for spawning worker threads to parse files (see
> AsyncTaskRunner::runAsync in tools/clang/tools/extra/clangd/Threading.cpp).
> Unfortunately, std::thread lacks the ability to customize the stack size,
> and the default one might be insufficient for parsing complex source files.
> For example, on macOS, the default stack size for non-main threads is 512K,
> so the following code causes a stack overflow (on my machine) with clangd,
> while being way below the default constexpr evaluation depth threshold:
>
>         constexpr int foo(int x) {
>             return x == 1 ? 1 : foo(x - 1) + 1;
>         }
>         static_assert(foo(50) > 0, "");
>
> This also can be observed on some real-world projects.
>
> Do I understand correctly that the only way to fix it would be to abandon
> std::thread and reimplement the platform-specific thread spawning (using
> pthreads/WinAPI), or is there another solution available in LLVM/clang
> codebase?
>
> Best regards,
> Dmitry Kozhevnikov._______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
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