Remove wasm32-freestanding-musl#22240
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andrewrk merged 2 commits intoziglang:masterfrom Dec 15, 2024
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It'll still pick .musl for os.tag == .wasi.
This is, at least today, a very broken target: It doesn't actually build either musl or wasi-libc even if you use -lc. It does give you musl headers, but that's it. Those headers are not terribly useful, however, without any implementation code. You can sort of call some math functions because they just so happen to have implementations in compiler-rt. But that's only true for a small subset, and I don't think users should be relying on the ABI surface of a library that is an implementation detail of the compiler. Clearly, a freestanding-capable libc of sorts is a useful thing as evidenced by newlib, picolibc, etc existing. However, calling it "musl" is misleading when it isn't actually musl-compatible, nor can it ever be because the musl API surface is inextricably tied to the Linux kernel. In the discussion on #20690, there was agreement that once we split up the API and ABI components in the target string, the API component should be about compatibility, not whether you literally get a particular implementation of it. Also, we decided that Linux musl and wasi-libc musl shouldn't use the same API tag precisely because they're not actually compatible. (And besides, how would any syscall even be implemented in freestanding? Who or what would we be calling?) So I think we should remove this triple for now. If we decide to reintroduce something like this, especially once #2879 gets going, we should come up with a bespoke name for it rather than using "musl".
This was referenced Apr 11, 2025
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This is, at least today, a very broken target: It doesn't actually build either musl or wasi-libc even if you use
-lc. It does give you musl headers, but that's it. Those headers are not terribly useful, however, without any implementation code. You can sort of call some math functions because they just so happen to have implementations in compiler-rt. But that's only true for a small subset, and I don't think users should be relying on the ABI surface of a library that is an implementation detail of the compiler.Clearly, a freestanding-capable libc of sorts is a useful thing as evidenced by newlib, picolibc, etc existing. However, calling it "musl" is misleading when it isn't actually musl-compatible, nor can it ever be because the musl API surface is inextricably tied to the Linux kernel. In the discussion on #20690, there was agreement that once we split up the API and ABI components in the target string, the API component should be about compatibility, not whether you literally get a particular implementation of it. Also, we decided that Linux musl and wasi-libc musl shouldn't use the same API tag precisely because they're not actually compatible.
(And besides, how would any syscall even be implemented in freestanding? Who or what would we be calling?)
So I think we should remove this triple for now. If we decide to reintroduce something like this, especially once #2879 gets going, we should come up with a bespoke name for it rather than using "musl".