5 ms·

> They are extremely complex, and were not designed for the use case e.g. relatively slow (designed to run offline on fast developer’s computers, or on even fas

• Const-me 6y ago
  I never tried to, but I think integration of runtime-generated native code gonna cause overhead. Where do you place these functions once compiled? Into a separate DLL/each? In .NET it’s quite easy to generate code that calls manually written functions, or access data provided by manually-written stuff. JIT runtime doesn’t treat generated code as something special, e.g. may inline calls across runtime-generated and manually written pieces of the program. With clang you gonna need a layer of indirection to integrate, with function pointers and such.
  • jcelerier 6y ago
    LLVM can just put the compiled code at some place in your ram and then you can just execute it
    • Const-me 6y ago
      Processors need addresses of things. Look at the following code https://godbolt.org/z/PYEqKn https://godbolt.org/z/PYEqKn note the function uses another symbol, “func.counter”. Shared libraries include relocation tables https://en.wikipedia.org/wiki/Relocation_%28computing%29 https://en.wikipedia.org/wiki/Relocation_%28computing%29 with all code locations which needs patching. That’s how the OSes can load them into arbitrary locations in memory and the code will still work.
      • jcelerier 6y ago
        ... yes ? https://github.com/weliveindetail/JitFromScratch https://github.com/weliveindetail/JitFromScratch
        • Const-me 6y ago
          Interesting, I didn’t know llvm is that flexible. Still, LLVM is a huge dependency to redistribute. And probably has many points of failure. For instance, I expect you gonna need to watch for INCLUDE and PATH environment variables when using that thing. In .NET everything is in the standard library. The generated code is even platform-independent, for no additional overhead. Here’s couple non-trivial examples: https://github.com/Const-me/ComLightInterop/blob/master/ComLight/Emit/Proxy.standard.cs https://github.com/Const-me/ComLightInterop/blob/master/ComL... https://github.com/Const-me/ComLightInterop/blob/master/ComLight/Emit/Proxy.custom.cs https://github.com/Const-me/ComLightInterop/blob/master/ComL...
          • SubjectToChange 6y ago
            > Still, LLVM is a huge dependency to redistribute. But .NET isn't?
            • Const-me 6y ago
              > But .NET isn't? Indeed. .NET runtime takes about 30 MB, or 50 MB if you're on Windows and need desktop components. Links there: https://dotnet.microsoft.com/download/dotnet/5.0 https://dotnet.microsoft.com/download/dotnet/5.0 clang+llvm package takes 300-400 MB, that's almost an order of magnitude difference: https://github.com/llvm/llvm-project/releases/tag/llvmorg-11.0.1 https://github.com/llvm/llvm-project/releases/tag/llvmorg-11...
              • jcelerier 6y ago
                > clang+llvm package takes 300-400 MB, that's almost an order of magnitude difference I ship a statically compiled llvm + clang with my software and it does not add 300-400 mb to the binary at all, only something like 20-30 mb.
    • namibj 6y ago
      I'll give Terra[0] as an example for something relatively high-level that uses LLVM as a JIT. It can also be used as an AoT compiler with fancy macro stuff in place of the C preprocessor. [0]: http://terralang.org/ http://terralang.org/