Auto merge of #136352 - lqd:ensure-stacks, r=compiler-errors

Add a couple of missing `ensure_sufficient_stacks`

r? `@saethlin` I hope you didn't spend time on this already.

(I couldn't sleep, opened `check_tail_calls`, there was a single call where it could happen, might as well fix it)

This PR adds a couple of missing `ensure_sufficient_stack`s:
- one in `check_tail_calls` that prevented the #135709 backport on some targets.
- after that was fixed, the test still didn't pass starting at 4MB, so I also added one in `check_unsafety` and that made it pass.

I didn't add an `rmake` test purposefully limiting the min stack size on `issue-74564-if-expr-stack-overflow.rs`, but we could if we wanted to.

On `apple-aarch64-darwin`, this is enough to make `RUST_MIN_STACK=$((1024*1024*3)) ./x test tests/ui --test-args tests/ui/issues/issue-74564-if-expr-stack-overflow.rs` pass for me locally, and it does stack overflow otherwise.

Author: bors

compiler/rustc_mir_build/src/check_tail_calls.rs

@@ -1,4 +1,5 @@
 use rustc_abi::ExternAbi;
+use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::Applicability;
 use rustc_hir::LangItem;
 use rustc_hir::def::DefKind;
@@ -344,12 +345,14 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for TailCallCkVisitor<'a, 'tcx> {
     }
 
     fn visit_expr(&mut self, expr: &'a Expr<'tcx>) {
-        if let ExprKind::Become { value } = expr.kind {
-            let call = &self.thir[value];
-            self.check_tail_call(call, expr);
-        }
+        ensure_sufficient_stack(|| {
+            if let ExprKind::Become { value } = expr.kind {
+                let call = &self.thir[value];
+                self.check_tail_call(call, expr);
+            }
 
-        visit::walk_expr(self, expr);
+            visit::walk_expr(self, expr);
+        });
     }
 }
 

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -2,6 +2,7 @@ use std::borrow::Cow;
 use std::mem;
 use std::ops::Bound;
 
+use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::DiagArgValue;
 use rustc_hir::def::DefKind;
 use rustc_hir::{self as hir, BindingMode, ByRef, HirId, Mutability};
@@ -476,7 +477,9 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
             ExprKind::Scope { value, lint_level: LintLevel::Explicit(hir_id), region_scope: _ } => {
                 let prev_id = self.hir_context;
                 self.hir_context = hir_id;
-                self.visit_expr(&self.thir[value]);
+                ensure_sufficient_stack(|| {
+                    self.visit_expr(&self.thir[value]);
+                });
                 self.hir_context = prev_id;
                 return; // don't visit the whole expression
             }