I changed to `wasm/abi.zig`, this design is certainly better than the previous one. Still there is some conflict of interest between llvm and self-hosted backend, better design will appear when abi tests will be tested with self-hosted.
Resolves: #23304Resolves: #23305
The last Intel Quark MCU was released in 2015. Quark was announced to be EOL in
2019, and stopped shipping entirely in 2022.
The OS tag was only meaningful for Intel's weird fork of Linux 3.8.7 with a
special ABI that differs from the regular i386 System V ABI; beyond that, the
CPU itself is just a plain old P54C (i586). We of course keep support for the
CPU itself, just not Intel's Linux fork.
* This has not seen meaningful development for about a decade.
* The Linux kernel port was never upstreamed.
* The glibc port was never upstreamed.
* GCC 15.1 recently deprecated support it.
It may still make sense to support an ILP32 ABI on AArch64 more broadly (which
we already have the Abi.ilp32 tag for), but, to the extent that it even existed
in any "official" sense, the *GNU* ILP32 ABI is certainly dead.
The "musl" part of the Zig target triples `wasm32-wasi-musl` and
`wasm32-emscripten-musl` refers to the libc, not really the ABI.
For WASM, most LLVM-based tooling uses `wasm32-wasi`, which is
normalized into `wasm32-unknown-wasi`, with an implicit `-unknown` and
without `-musl`.
Similarly, Emscripten uses `wasm32-unknown-emscripten` without `-musl`.
By using `-unknown` instead of `-musl` we get better compatibility with
external tooling.
Emscripten currently implements `emscripten_return_address()` by calling
out into JavaScript and parsing a stack trace, which introduces
significant overhead that we would prefer to avoid in release builds.
This is especially problematic for allocators because the generic parts
of `std.mem.Allocator` make frequent use of `@returnAddress`, even
though very few allocator implementations even observe the return
address, which makes allocators nigh unusable for performance-critical
applications like games if the compiler is unable to devirtualize the
allocator calls.
Too many bugs have been found with `truncate` at this point, so it was
rewritten from scratch.
Based on the doc comment, the utility of `convertToTwosComplement` over
`r.truncate(a, .unsigned, bit_count)` is unclear and it has a subtle
behavior difference that is almost certainly a bug, so it was deleted.
This should be a lot easier to maintain. It's also a small step towards
eventually making the builder API parse the data layout string in order to
answer layout questions that we need to ask during code generation.
