/format

🌈 Formatted, please merge the changes from this PR

I'm using .slang-modules as input to slangc to compile CPU-targeting Slang using a custom CMake toolchain, and would like this feature to stay. I can probably somehow work around it though if necessary.

Particularly, CMake toolchains need a way for the compiler to generate object files from sources (CMAKE_Slang_COMPILE_OBJECT). I use this to generate .slang-module files. Then, a linking stage is needed (CMAKE_Slang_LINK_EXECUTABLE), which I've implemented by feeding these object files (.slang-modules) to slangc with -target executable. Splitting them this way allows for parallel compilation (or in reality, mostly just parallel parsing I guess) of the sources in CMake.

I think I could live with CMAKE_Slang_COMPILE_OBJECT just copying the Slang source as-is, so removing this feature would likely just be a slight inconvenience.

@juliusikkala Thanks for the feedback!

This PR is definitely just an attempt on my part to find the boundaries between what is and isn't being used when it comes to this functinality, so knowing that passing a .slang-module on the command line is a useful behavior helps a lot.

Also, FWIW, I strongly agree that the behavior you describe is desirable, for the reasons you went into. It's not that I don't think slangc should have that behavior, and its more just that the way that behavior is currently implemented in the compiler is tangled up in several overly-complicated features, so that ideally we could do something a lot more narrow that would meet your needs.

I'm going to keep iterating on this work, but for now your comment plus the various test failures (including some user code integration tests I've run internally) tell me that I can't just do the easy thing and eliminate this functionality entirely.