On Thu, May 19, 2016 at 2:59 AM, Emanuel Hoogeveen < emanuel.hoogev...@gmail.com> wrote:
> They do get the baseline compiler, which can still be significantly faster > than the interpreter, but Ion requires SSE2. Since the runtime detection > does just turn Ion off altogether, I don't know if we would gain much by > removing it (the ability to disable Ion isn't going away). > We will have to make a similar decision for WebAssembly. Odin (our Ion-based asm.js compiler) requires SSE2, but there we can at least use the much slower 'normal JS' path. For WebAssembly, we have the following options IIUC: (1) Don't support wasm on those ancient CPUs. This may work for a while, but at some point we may include wasm modules in Firefox, normal websites will start to use it, etc. (2) Add x87 floating-point support to the wasm baseline JIT - very complicated and likely not worth it. (3) Call into C++ for all floating point and SIMD operations. This will be horribly slow. (4) Add a wasm interpreter. Again, likely not worth the effort if it's just for this. Jan > IIRC our fuzzers already compile with SSE2 enabled to avoid hitting > floating point differences during differential testing (testing the > interpreter against baseline, against Ion). Enabling SSE2 for all builds > would remove those differences, which might be beneficial in its own right > (since content JS running in Ion would no longer behave differently than in > baseline or the interpreter). > _______________________________________________ > dev-platform mailing list > dev-platform@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-platform > _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
