Build dxcompiler dependency for MacOS

libsdl-org / SDL_shadercross

Shader translation library for SDL's GPU API.

zlib License

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Build dxcompiler dependency for MacOS #38

Closed thatcosmonaut closed 3 days ago

thatcosmonaut commented 2 weeks ago

This is required for cross-platform HLSL workflows.

flibitijibibo commented 2 weeks ago

Since we'd have to build it anyway, should we also link this statically? I guess it would depend on whether or not the dxil-less builds are still technically proprietary, otherwise it'd ensure the one DLL supports all configurations (which would help obsolete #28)

TheSpydog commented 2 weeks ago

It’d be really nice if we could, but…

https://devlog.hexops.com/2024/building-the-directx-shader-compiler-better-than-microsoft/#well-why-not-just-statically-link-against-it

I wonder if the situation has improved at all since this blog post was written. Integrating DXIL signing into dxcompiler itself solves at least that problem, but I have no idea about the build system.

thatcosmonaut commented 2 weeks ago

This might be something we can do more easily once HLSL is upstreamed into clang.

thatcosmonaut commented 2 weeks ago

To recap:

It's basically impossible to statically link dxcompiler at this time due to Microsoft's bungled build setup.
The only scenarios where dxcompiler is actually needed at runtime are when clients are shipping HLSL source or when compiling SPIR-V to DXIL on Windows at runtime. At some point in the future even the latter workflow will be obsoleted as Microsoft plans to accept SPIR-V directly as a bytecode format.
Microsoft doesn't provide libdxcompiler builds for MacOS, so we need to build and package it ourselves.
At some point in the future when HLSL support is upstreamed into clang, we can revisit statically including dxcompiler.

thatcosmonaut commented 3 days ago

Resolved by https://github.com/libsdl-org/SDL_gpu_shadercross/commit/933e058bc2f442461b4358b3fc2e896c34775478