Calling function with bad signature, Rust 0.13.0-nightly

[alexispurslane]

So, i am compileing a version of rustboot that uses some changes that someone else had made so that it could display text on the screen, but when I compile I get this:

rustc: /home/rustbuild/src/rust-buildbot/slave/nightly-linux/build/src/llvm/lib/IR/Instructions.cpp:276: void llvm::CallInst::init(llvm::Value*, llvm::ArrayRef<llvm::Value*>, const llvm::Twine&): Assertion `(Args.size() == FTy->getNumParams() || (FTy->isVarArg() && Args.size() > FTy->getNumParams())) && "Calling a function with bad signature!"' failed.
make: *** [main.o] Aborted (core dumped)

i have checked all the other issues about this, but none of them have helped. My code looks like this:

#![no_std]
#![allow(ctypes)]
#![feature(lang_items)]

#[allow(dead_code)]
enum Color {
    Black      = 0,
    Blue       = 1,
    Green      = 2,
    Cyan       = 3,
    Red        = 4,
    Pink       = 5,
    Brown      = 6,
    LightGray  = 7,
    DarkGray   = 8,
    LightBlue  = 9,
    LightGreen = 10,
    LightCyan  = 11,
    LightRed   = 12,
    LightPink  = 13,
    Yellow     = 14,
    White      = 15,
}

enum DisplayInfo {
    VGAWIDTH = 80,
    VGAHEIGHT = 25,
    VGAADDRESS = 0xb8000,
}

#[lang="sized"]
fn clear_screen(background: Color) {
    let limit = 80u * 25u;
    let mut i = 0u;
    while i < limit {
        unsafe {
            *((VGAADDRESS as u16 + i as u16 * 2) as *mut u16) = (background as u16) << 12;
        }
        i += 1;
    }
}

fn make_vgaentry(c: u8, fg: Color, bg: Color) -> u16 {
    let color = fg as u16 | (bg as u16 << 4);
    c as u16 | (color << 8)
}
pub fn putc(x: u16, y: u16, c: u8) {
    let idx: uint = (y * VGAWIDTH as u16 * 2 + x * 2) as uint;
    unsafe {
        *((VGAADDRESS as u16 + idx as u16) as *mut u16) = make_vgaentry(c, Green, Black)
    }
}

#[lang="fail_bounds_check"]
pub fn write_x_y(s: &[u8], x: u16, y: u16, len: uint) {
    let mut i = 0u;
    while i < len {
        putc(x + i as u16, y, s[i]);
        i += 1;
    }
}


#[no_mangle]
#[no_split_stack]
pub fn main() {
    clear_screen(Black);
    let prompt = b"==> ";
    write_x_y(prompt, 2, 3, 4);
}

I am fairly new to rust, and pretty much copy-and-pasteing stuff in. You will notice I cannot program very rust-idiomaticly becouse I have to do without the standard library, and cannot compile libcore for i386-intel-linux, which is what the loader assembly code is written for.

[bkoropoff]

I'm guessing it's due to #[lang="fail_bounds_check"] being attached to write_x_y. It needs to be attached to a separate function with the correct prototype:

#[lang="fail_bounds_check"]
fn fail_bounds_check(file_line: &(&'static str, uint), index: uint, len: uint) -> ! {
    // This should probably do something more intelligent
    loop {}
}

The sized lang item also needs to be attached to a trait:

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

This bug should be left open, though, as the compiler should give an error message instead of asserting in llvm.

[ghost]

The issue tracking type checking of lang items is #9307.

[alexispurslane]

Cool, thanks. I hope I'm not making myself a nuisance, but when I compile my code with your changes, I get:

main.o: In function `write_x_y::h7be34e5c69623465Tda':
main.0.rs:(.text._ZN9write_x_y20h7be34e5c69623465TdaE+0x14): undefined reference to `__morestack'
make: *** [main.bin] Error 1

I looked through my code, and I don't actually see a reference anywhere to __morestack. At least it is a different error! ]-:

[thestinger]

Closing as a duplicate of #9307.