SIGSEGV when compiling for wasm #60540
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Labels
A-LLVM
Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues.
C-bug
Category: This is a bug.
I-crash
Issue: The compiler crashes (SIGSEGV, SIGABRT, etc). Use I-ICE instead when the compiler panics.
I-unsound
Issue: A soundness hole (worst kind of bug), see: https://en.wikipedia.org/wiki/Soundness
O-wasm
Target: WASM (WebAssembly), http://webassembly.org/
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
Comments
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Got backtraces for all thread by loading a core dump: |
jonas-schievink
added
C-bug
|
After trying compiling it many times it does succeed, but the resulting wasm file is corrupt: |
Centril
added
the
I-unsound
|
Based on ^-- I'm tentatively labeling as a soundness hole since it seems that type preservation is violated? (Haven't looked closely) |
|
Reduced repro: $ rustc lib.rs --crate-type lib --target wasm32-unknown-wasilib.rs#![allow(unused_variables)]
type ExpInt = i16;
type Limb = u128;
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum Loss {
ExactlyZero,
}
fn shift_left(dst: &mut [Limb], exp: &mut ExpInt, bits: usize) {
loop {}
}
fn shift_right(dst: &mut [Limb], exp: &mut ExpInt, bits: usize) -> Loss {
loop {}
}
fn sub(a: &mut [Limb], b: &[Limb], c: Limb) -> Limb {
loop {}
}
pub fn add_or_sub(
a_sig: &mut [Limb],
a_exp: &mut ExpInt,
a_sign: &mut bool,
b_sig: &mut [Limb],
b_exp: ExpInt,
b_sign: bool,
) {
let bits = *a_exp - b_exp;
let (reverse, loss);
if bits == 0 {
loop {}
} else if bits > 0 {
loss = shift_right(b_sig, &mut 0, (bits - 1) as usize);
shift_left(a_sig, a_exp, 1);
reverse = false;
} else {
loss = shift_right(a_sig, a_exp, (-bits - 1) as usize);
shift_left(b_sig, &mut 0, 1);
reverse = true;
}
let borrow = (loss != Loss::ExactlyZero) as Limb;
if reverse {
assert_eq!(sub(b_sig, a_sig, borrow), 0);
}
}Edit: Reduced it even more. |
I've got a bit more specific one from Node.js:
|
|
LLVM IR for @bjorn3's reproducer: https://gist.github.com/nikic/fb45d54844f6feb698a309418e948866 Running this through With backtrace: |
nikic
added
the
A-LLVM
|
Reduced test case: |
|
Upstream report: https://bugs.llvm.org/show_bug.cgi?id=41841 |
|
Fixed upstream: llvm/llvm-project@323dc63 |
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this issue
May 14, 2019
More details can be found in rust-lang#60540! Closes rust-lang#60540
Centril
added a commit
to Centril/rust
that referenced
this issue
May 15, 2019
…=nikic Update LLVM to fix assertion when compiling to wasm More details can be found in rust-lang#60540! Closes rust-lang#60540
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Unfortunately I can't get a backtrace as running inside a debugger prevents it from crashing.
Reproduction:
Clone https://github.com/bjorn3/rust. Checkout commit 8c17e4aec8e187addf8fc187b64bd411a6038dea and follow the instructions on the top of the readme. Sometimes the execution succeeds, so you may have to remove the
targetdir when it succeeded.The text was updated successfully, but these errors were encountered: