Should be able to change stack limit

[orium]

It is currently not possible to change the stack limit. It would be great to get that functionality back!

Original report

Maybe I'm doing something wrong, but I'm unable to set the stack limit for miri.

If I call cargo miri test --help it says:

The config flag `miri` is automatically defined for convenience. You can use
it to configure the resource limits

    #![cfg_attr(miri, memory_size = 42)]

available resource limits are `memory_size`, `step_limit`, `stack_limit`

After adding

#![cfg_attr(miri, stack_limit = 100000)]

to my lib.rs I get "stack limit reached error" at the same depth.

[RalfJung]

@oli-obk did that get lost in the move to rustc?

[orium]

I think it was. From quickly grepping rustc's repository it looks like this value is hardcoded to 100:

https://github.com/rust-lang/rust/blob/f47ec2ad5b6887b3d400aee49e2294bd27733d18/src/librustc/session/mod.rs#L1188

I didn't find any place where this field gets changed (https://github.com/rust-lang/rust/search?q=const_eval_stack_frame_limit).

Not sure about the other configurations (memory_size, step_limit).

[oli-obk]

Hm. yes, they seem to have gotten lost. We should probably just remove that limitation entirely, just like we got rid of the memory limit.

[orium]

Currently rustc uses this stack_limit = 100 when evaluating const fn.

Do we want to keep this limit for compilation?

[oli-obk]

For const eval we can just use the recursion limit, which is already configurable by users

[RalfJung]

The bug part of this is now "fixed" by removing this text from --help.

I am turning this into a ticket to track the enhancement request that the stack limit should be changeable.

[CAD97]

I think rust-lang/rust#66726 should address this?

I would just like to note that I hit the stack frame limit exactly, which prompted me to check how difficult it'd be to change this:

>cargo miri test
[...]
error: Miri evaluation error: reached the configured maximum number of stack frames
   --> D:\usr\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\src\libcore\mem\mod.rs:245:5
    |
245 |     intrinsics::size_of::<T>()
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ Miri evaluation error: reached the configured maximum number of stack frames
    |