Prevent compiler stack overflow for deeply recursive code
I was unable to write a test that
1. runs in under 1s
2. overflows on my machine without this patch
The following reproduces the issue, but I don't think it's sensible to include a test that takes 30s to compile. We can now easily squash newly appearing overflows by the strategic insertion of calls to `ensure_sufficient_stack`.
```rust
// compile-pass
#![recursion_limit="1000000"]
macro_rules! chain {
(EE $e:expr) => {$e.sin()};
(RECURSE $i:ident $e:expr) => {chain!($i chain!($i chain!($i chain!($i $e))))};
(Z $e:expr) => {chain!(RECURSE EE $e)};
(Y $e:expr) => {chain!(RECURSE Z $e)};
(X $e:expr) => {chain!(RECURSE Y $e)};
(A $e:expr) => {chain!(RECURSE X $e)};
(B $e:expr) => {chain!(RECURSE A $e)};
(C $e:expr) => {chain!(RECURSE B $e)};
// causes overflow on x86_64 linux
// less than 1 second until overflow on test machine
// after overflow has been fixed, takes 30s to compile :/
(D $e:expr) => {chain!(RECURSE C $e)};
(E $e:expr) => {chain!(RECURSE D $e)};
(F $e:expr) => {chain!(RECURSE E $e)};
// more than 10 seconds
(G $e:expr) => {chain!(RECURSE F $e)};
(H $e:expr) => {chain!(RECURSE G $e)};
(I $e:expr) => {chain!(RECURSE H $e)};
(J $e:expr) => {chain!(RECURSE I $e)};
(K $e:expr) => {chain!(RECURSE J $e)};
(L $e:expr) => {chain!(RECURSE L $e)};
}
fn main() {
let x = chain!(D 42.0_f32);
}
```
fixes#55471fixes#41884fixes#40161fixes#34844fixes#32594
cc @alexcrichton @rust-lang/compiler
I looked at all code that checks the recursion limit and inserted stack growth calls where appropriate.
97f3eeec82