CoreRegs::default() causes stack overflow

[6293]

Current Behavior

#[test]
fn my_test() { let _register = CoreRegs::default(); }

fails with

thread 'isa::exec::tests::my_test' has overflowed its stack
fatal runtime error: stack overflow

Cause

https://github.com/internet2-org/rust-aluvm/blob/a7e64abd4a7058bf9f06886452147810b4a5cf6d/src/reg/core_regs.rs#L99
With Box<[LibSite; CALL_STACK_SIZE]>, the value would be allocated to stack first, but CALL_STACK_SIZE = 1 << 16 is too big, resuting in overflow.

Possible Solutions

Use Vec<LibSite> instead.

Related Issues

rust-lang/rust#53827

[6293]

It is a bit weird that
https://github.com/internet2-org/rust-aluvm/blob/a7e64abd4a7058bf9f06886452147810b4a5cf6d/src/isa/asm.rs#L39 does not fail (because Vm::<Instr>::with calls CoreRegs::default()), but when I modified CALL_STACK_SIZE to 1 << 18, this also overflowed. So most likely 1 << 16 is near the boundary

[dr-orlovsky]

This is bad - and caused by rust compiler bug. It may be changed with stabilizing alternative box syntax, but nobody knows when (and would) it happen.

The worst is that this limits for the size are platform-dependent and will overflow on different platforms at different boundaries...

Vec seems to be the only solution here, you are right.