Fail to build compiler-builtins for target x86_64-pc-windows-gnu

[malbarbo]

> git clone https://github.com/rust-lang-nursery/compiler-builtins
> compiler-builtins

Works with nightly-2017-04-25 (llvm 3.9)

> rustup toolchain install nightly-2017-04-25
> rustup target add --toolchain nightly-2017-04-25 x86_64-pc-windows-gnu
> rustc +nightly-2017-04-25 -v --version
rustc 1.18.0-nightly (63c77214c 2017-04-24)
binary: rustc
commit-hash: 63c77214c1d38789652b465694b254205d1886e0
commit-date: 2017-04-24
host: x86_64-unknown-linux-gnu
release: 1.18.0-nightly
LLVM version: 3.9
> cargo +nightly-2017-04-25 build --target x86_64-pc-windows-gnu
   Compiling compiler_builtins v0.1.0 (file:///tmp/compiler-builtins)
    Finished dev [unoptimized + debuginfo] target(s) in 2.11 secs

Fails with nightly-2017-04-26 (llvm 4.0)

> rustup toolchain install nightly-2017-04-26
> rustup target add --toolchain nightly-2017-04-26 x86_64-pc-windows-gnu
> rustc +nightly-2017-04-26 -v --version
rustc 1.18.0-nightly (2b4c91158 2017-04-25)
binary: rustc
commit-hash: 2b4c911581099e247a68b3a8adc782d778f5190b
commit-date: 2017-04-25
host: x86_64-unknown-linux-gnu
release: 1.18.0-nightly
LLVM version: 4.0
> cargo +nightly-2017-04-26 build --target x86_64-pc-windows-gnu
   Compiling compiler_builtins v0.1.0 (file:///tmp/compiler-builtins)
rustc: /checkout/src/llvm/include/llvm/CodeGen/MachineFunction.h:452: bool llvm::MachineFunction::hasWinCFI() const: Assertion `HasWinCFI.hasValue() && "HasWinCFI not set yet!"' failed.
error: Could not compile `compiler_builtins`.

[malbarbo]

@TimNN Do you have some thought about this?

[TimNN]

Sorry, I'm not really that much of a windows expert, although I can try and minify / reproduce if that also occurs when cross-compiling.

[malbarbo]

Thanks for your attention @TimNN. I'm cross compiling from a Linux machine. I minified the case. The problems seems to be with naked functions

#![feature(naked_functions)]

#[cfg(windows)]
#[naked]
pub unsafe fn f() {}

pub fn main() {}

Do you have any suggestion who to contact?

[TimNN]

This affects 64bit MinGW and Msvc targets, here is a non-core repro:

#![feature(lang_items, naked_functions, no_core)]
#![crate_type = "lib"]
#![no_core]

#[lang = "sized"]
trait Sized {}

#[lang = "copy"]
trait Copy {}

#[naked]
unsafe fn _f() {}

I'l get try and get some minified IR.

Nominating since this breaks rust-lang-nursery.

[TimNN]

IR:

target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-windows-msvc"

define internal void @_ZN5naked2_f17h37d58925d66289bcE() naked {
start:
  ret void
}

Upstream bug: https://bugs.llvm.org/show_bug.cgi?id=32912

[TimNN]

Potential patch: https://reviews.llvm.org/D32822

Edit: Another patch has been committed: llvm-mirror/llvm@6e53fe2