Building with --cfg disable_float still generates SSE error

[hawkw]

I'm trying to build libcore from this repo using a target that disables SSE. When I run rustc with --cfg disable_float, I still get LLVM ERROR: SSE register return with SSE disabled.

Here's the whole command:

$ rustc --verbose --target x86_64-unknown-none-gnu --cfg disable_float -Z no-landing-pads lib/libcore/src/lib.rs
LLVM ERROR: SSE register return with SSE disabled

And here's my x86_64-unknown-none-gnu target:

{
    "llvm-target": "x86_64-unknown-none-gnu",
    "target-endian": "little",
    "target-pointer-width": "64",
    "os": "none",
    "arch": "x86_64",
    "data-layout": "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128",
    "pre-link-args": [ "-m64" ],
    "cpu": "x86-64",
    "features": "-mmx,-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-3dnow,-3dnowa,-avx,-avx2",
    "disable-redzone": true,
    "eliminate-frame-pointer": true,
    "linker-is-gnu": true,
    "no-compiler-rt": true,
    "archive-format": "gnu"
}

It's quite possible that I'm doing something wrong and this is my fault, but I'm really not sure what. Otherwise, it seems to me that there must be some floating-point code somewhere in libcore that the disable_float config doesn't disable. It's possible that something was added after the version of libcore that the patch was written against, I suppose?

Any help with this issue would be greatly appreciated. Thanks!

[phil-opp]

I'm on mobile right now, so just a guess:

Try building it using cargo, see the Readme for instructions. Config flags of rustc are different to cargo features. I think the correct flag for rustc would be something like --cfg "feature = disable_float".

[hawkw]

Oh, thank you so much, that fixes it. Building with cargo works just fine. For rustc, the option you gave is almost correct, but the "disable_float" needs (escaped) quotes, so it's actually --cfg "feature = \"disable_float\"". Thank you!

[phil-opp]

Great! Thanks for the rustc flag, maybe I should add it to the Readme.

[phil-opp]

Btw, I created the same thing for liballoc and libcollections as well. Maybe it's useful.

I plan to add some scripts to automate the needed steps. But I'm pretty busy at the moment, so it will take some time

[hawkw]

Oh, neat, I hadn't realised that. I'm currently including submodules for both nightly-libcore and the main Rust repo for liballoc, libcollections, and librustc_unicode, but my project might clone much faster if I just included your repos for those libraries, since I wouldn't need to clone the entire Rust repository....