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Additional details from author here.


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    Wow. The performance of this thing is nuts. Loving it.

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      For more details about “how” zapcc caches (at a high level), there are some talk slides in a PDF in the repo: https://raw.githubusercontent.com/yrnkrn/zapcc/51f37ca2b46b48862d7dec4010f06f50483433d9/docs/zapcc/catc17-zapcc-an-accelerating-c-compiler.pdf

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        That’s great. Thanks for the link!

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          No worries. I got to the end of the README and went digging around for some more high-level details of what zapcc was doing, noticed that.

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        No, caching is disabled for C files.

        …any idea why? I wouldn’t expect a huge speedup, because C headers aren’t entirely insane, but it seems an odd decision.

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          I noticed that the 2015 mailing list post says .c files are cached, so some time between then and the 2018 public release it was disabled for C.

          If I had to guess, the actual parsing pass is always going to be a lot less complex for C vs C++, so a simpler approach like ccache’s may get similar gains for less overhead generating & maintaining the actual cache.

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            I agree. I push caching as the general rule if checking if it’s in the cache costs less than the time to compile the file. I’d think that was true for most languages.