cargo +nightly-i686-pc-windows-msvc build crashes with very little info on what caused the error

[super-continent]

I'm attempting to build a small project I've been working on for 32-bit systems, it builds fine on 64-bit but after some quick porting rustc just crashes and outputs that the process didn't return successfully.

All the code I was attempting to compile can be found in this repo

I'm unsure what the actual cause of the bug is, as the output data with the -vv flag added only outputs the commands used to compile, no ICE or anything else, unsure what to make of it.

rustc --version --verbose:

rustc 1.46.0-nightly (e55d3f9c5 2020-06-18)
binary: rustc
commit-hash: e55d3f9c5213fe1a25366450127bdff67ad1eca2
commit-date: 2020-06-18
host: i686-pc-windows-msvc
release: 1.46.0-nightly
LLVM version: 10.0

[tesuji]

Try to run rustc in debugger like lldb or visual studio.

[super-continent]

I ran it in Visual Studio JIT debugger on crash and it gives me an unhandled exception for 0x10FD8305 (rustc_driver-c2b8445fecb811f3.dll) in rustc.exe: 0xC0000005: Access violation reading location 0x00007E47.

There seems to be a point where it accesses [EAX(0x7E3B) + 0x0C] and crashes, not sure how I would figure out where exactly in the program this is happening, are there debug symbols available?

[super-continent]

Ok, I set RUSTC_LOG so it outputs info and heres the last 20 lines before a crash happens in the log. This probably narrows down the scope of where the issue might be, right?

[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::align_of_val::<alloc::sync::ArcInner<std::cell::UnsafeCell<std::option::Option<std::result::Result<(), std::boxed::Box<dyn std::any::Any + std::marker::Send>>>>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::align_of_val::<alloc::sync::ArcInner<std::sync::Mutex<helpers::Config>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::align_of_val::<alloc::sync::ArcInner<std::sync::Mutex<std::vec::Vec<std::vec::Vec<u8>>>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::align_of_val::<alloc::sync::ArcInner<std::thread::Inner>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::ManuallyDrop::<std::vec::Vec<u8>>::new)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::ManuallyDrop::<std::boxed::Box<detour::detours::generic::GenericDetour<extern "win64" fn(u32, u32, u32)>>>::new)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::min_align_of_val::<alloc::sync::ArcInner<std::sync::Mutex<std::vec::Vec<std::vec::Vec<u8>>>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::min_align_of_val::<alloc::sync::ArcInner<std::cell::UnsafeCell<std::option::Option<std::result::Result<(), std::boxed::Box<dyn std::any::Any + std::marker::Send>>>>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::min_align_of_val::<alloc::sync::ArcInner<std::thread::Inner>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::min_align_of_val::<alloc::sync::ArcInner<std::sync::Mutex<helpers::Config>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::drop::<std::sync::Weak<std::cell::UnsafeCell<std::option::Option<std::result::Result<(), std::boxed::Box<dyn std::any::Any + std::marker::Send>>>>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::drop::<std::boxed::Box<std::boxed::Box<dyn std::ops::Fn(u32, u32, u32)>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::drop::<std::sync::Weak<std::thread::Inner>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::drop::<std::sync::Weak<std::sync::Mutex<std::vec::Vec<std::vec::Vec<u8>>>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::drop::<std::sync::Weak<std::sync::Mutex<helpers::Config>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::forget::<std::vec::Vec<u8>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::mem::forget::<std::boxed::Box<detour::detours::generic::GenericDetour<extern "win64" fn(u32, u32, u32)>>>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::option::Option::<usize>::unwrap_or_else::<fn() -> usize {std::sys_common::thread::min_stack}>)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::option::Option::<&std::boxed::Box<dyn std::ops::Fn(u32, u32, u32)>>::ok_or::<detour::error::Error>)
error: could not compile `win32-dll-test`.

[super-continent]

If I do cargo clean before building I get this output, seems to crash before that too.

[INFO  rustc_codegen_ssa::base] codegen_instance(<std::mem::ManuallyDrop<std::panic::AssertUnwindSafe<[closure@std::thread::Builder::spawn_unchecked::{{closure}}#0::{{closure}}#0 0:fn() {initialize}]>> as std::ops::DerefMut>::deref_mut)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::string::String::new)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::string::String::from_utf8)
[INFO  rustc_codegen_ssa::base] codegen_instance(<std::string::String as std::fmt::Display>::fmt)
[INFO  rustc_codegen_ssa::base] codegen_instance(<std::string::String as std::string::ToString>::to_string)
[INFO  rustc_codegen_ssa::base] codegen_instance(<std::string::String as std::ops::Deref>::deref)
[INFO  rustc_codegen_ssa::base] codegen_instance(<std::string::String as std::convert::AsRef<str>>::as_ref)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::sync::atomic::AtomicBool::load)
[INFO  rustc_codegen_ssa::base] codegen_instance(std::sync::atomic::AtomicBool::store)
error: could not compile `win32-dll-test`.

[super-continent]

Is there any speculation possible on what the issue is? This is preventing me entirely from working on a project I want to start and I've been unsuccessful in figuring out the problem

[super-continent]

Re-ran in debugger, seems that there is now a UD2 instruction in the execution? This is what my VS debug disassembly shows, throws exception as the instruction normally does. Odd thing is that before the crash was from an invalid memory access

[workingjubilee]

Triaging this... very peculiar. Appears to deal with codegen. Only on 32-bit.