Rollup merge of #122847 - workingjubilee:suggest-rust-min-stack-workaround-on-overflow, r=TaKO8Ki

Suggest `RUST_MIN_STACK` workaround on overflow

For some Rust crates, like p384, we can't do a whole lot about it even if the stack overflow is reported like in rust-lang/rust#122357 because the problem may be inside LLVM or another codegen backend. We can, however, suggest people set a new `RUST_MIN_STACK` value while handling the SIGSEGV, as that stack-setting will carry forward into the dylib.

As a bonus, this also leads to cleaning up the stack-setting code a bit.

1 files changed, 5 insertions, 1 deletions

diff --git a/compiler/rustc_driver_impl/src/signal_handler.rs b/compiler/rustc_driver_impl/src/signal_handler.rs
index deca1082221..441219eec90 100644
--- a/compiler/rustc_driver_impl/src/signal_handler.rs
+++ b/compiler/rustc_driver_impl/src/signal_handler.rs
@@ -1,6 +1,7 @@
 //! Signal handler for rustc
 //! Primarily used to extract a backtrace from stack overflow
 
+use rustc_interface::util::{DEFAULT_STACK_SIZE, STACK_SIZE};
 use std::alloc::{alloc, Layout};
 use std::{fmt, mem, ptr};
 
@@ -100,7 +101,10 @@ extern "C" fn print_stack_trace(_: libc::c_int) {
         written += 1;
     }
     raw_errln!("note: we would appreciate a report at https://github.com/rust-lang/rust");
-    written += 1;
+    // get the current stack size WITHOUT blocking and double it
+    let new_size = STACK_SIZE.get().copied().unwrap_or(DEFAULT_STACK_SIZE) * 2;
+    raw_errln!("help: you can increase rustc's stack size by setting RUST_MIN_STACK={new_size}");
+    written += 2;
     if written > 24 {
         // We probably just scrolled the earlier "we got SIGSEGV" message off the terminal
         raw_errln!("note: backtrace dumped due to SIGSEGV! resuming signal");