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.
perf: Unify the undo log of all snapshot types
Extracted from #69218 and extended to all the current snapshot types.
Since snapshotting is such a frequent action in the compiler and many of the scopes execute so little work, the act of creating the snapshot and rolling back empty/small snapshots end up showing in perf. By unifying all the logs into one the creation of snapshots becomes significantly cheaper at the cost of some complexity when combining the log with the specific data structures that are being mutated.
Depends on https://github.com/rust-lang-nursery/ena/pull/29
In addition to fixing the toolstate, this also changes the default
compilation model to the out-of-process one, which should hopefully
target considerable memory usage for long-running instances of the RLS.
By merging the undo_log of all structures part of the snapshot the cost
of creating a snapshot becomes much cheaper. Since snapshots with no or
few changes are so frequent this ends up mattering more than the slight
overhead of dispatching on the variants that map to each field.
Implement `confusable_idents` lint.
This collects all identifier symbols into `ParseSession` and examines them within the non-ascii-idents lint.
The skeleton generation part needs to be added to `unicode-security` crate. Will update this PR when the crate is updated.
r? @petrochenkov
EDIT: also included the `concat_idents` part.
We anticipate this to have uses in all sorts of crates and keeping it in
`rustc_data_structures` enables access to it from more locations without
necessarily pulling in the large `librustc` crate.
Miri: port error backtraces to std::backtrace
No need to pull in an external dependency if libstd already includes this feature (using the same dependency internally, but... still).
r? @oli-obk
Have the per-query caches store the results on arenas
This PR leverages the cache for each query to serve as storage area for the query results.
It introduces a new cache `ArenaCache`, which moves the result to an arena,
and only stores the reference in the hash map.
This allows to remove a sizeable part of the usage of the global `TyCtxt` arena.
I only migrated queries that already used arenas before.
Update backtrace-sys
Diff:
- Don't look for old RUSTC_DEBUGINFO vars (rust-lang/backtrace-rs#313)
This fixes an issue of libbacktrace never being built with debuginfo.
r? @Mark-Simulacrum
cc @alexcrichton
Move `{Free,}RegionRelations` and `FreeRegionMap` to `rustc_infer`
...and out of `rustc_middle`. This is to further #65031, albeit in a very minor way
r? @Mark-Simulacrum
Detect mistyped associated consts in `Instance::resolve`.
*Based on #71049 to prevent redundant/misleading downstream errors.*
Fixes#70942 by refusing to resolve an associated `const` if it doesn't have the same type in the `impl` that it does in the `trait` (which we assume had errored, and `delay_span_bug` guards against bugs).
Deprecate the asm! macro in favor of llvm_asm!
Since we will be changing the syntax of `asm!` soon, deprecate it and encourage people to use `llvm_asm!` instead (which preserves the old syntax). This will avoid breakage when `asm!` is changed.
RFC: https://github.com/rust-lang/rfcs/pull/2843
