Auto merge of rust-lang#116088 - nbdd0121:unwind, r=Amanieu,RalfJung

Stabilise `c_unwind`

Fix rust-lang#74990
Fix rust-lang#115285 (that's also where FCP is happening)

Marking as draft PR for now due to `compiler_builtins` issues

r? `@Amanieu`

alloc/src/lib.rs

@@ -165,12 +165,12 @@
 //
 // Language features:
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(c_unwind))]
 #![cfg_attr(not(test), feature(coroutine_trait))]
 #![cfg_attr(test, feature(panic_update_hook))]
 #![cfg_attr(test, feature(test))]
 #![feature(allocator_internals)]
 #![feature(allow_internal_unstable)]
-#![feature(c_unwind)]
 #![feature(cfg_sanitize)]
 #![feature(const_mut_refs)]
 #![feature(const_precise_live_drops)]

core/src/lib.rs

@@ -199,13 +199,13 @@
 //
 // Language features:
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(c_unwind))]
 #![feature(abi_unadjusted)]
 #![feature(adt_const_params)]
 #![feature(allow_internal_unsafe)]
 #![feature(allow_internal_unstable)]
 #![feature(asm_const)]
 #![feature(auto_traits)]
-#![feature(c_unwind)]
 #![feature(cfg_sanitize)]
 #![feature(cfg_target_has_atomic)]
 #![feature(cfg_target_has_atomic_equal_alignment)]

panic_abort/src/lib.rs

@@ -14,7 +14,7 @@
 #![feature(std_internals)]
 #![feature(staged_api)]
 #![feature(rustc_attrs)]
-#![feature(c_unwind)]
+#![cfg_attr(bootstrap, feature(c_unwind))]
 #![allow(internal_features)]
 
 #[cfg(target_os = "android")]

panic_unwind/src/lib.rs

@@ -24,7 +24,7 @@
 #![feature(rustc_attrs)]
 #![panic_runtime]
 #![feature(panic_runtime)]
-#![feature(c_unwind)]
+#![cfg_attr(bootstrap, feature(c_unwind))]
 // `real_imp` is unused with Miri, so silence warnings.
 #![cfg_attr(miri, allow(dead_code))]
 #![allow(internal_features)]

proc_macro/src/bridge/buffer.rs

@@ -119,7 +119,9 @@ impl Write for Buffer {
 }
 
 impl Drop for Buffer {
-    #[inline]
+    // HACK(nbdd0121): Hack to prevent LLVM < 17.0.4 from misoptimising,
+    // change to `#[inline]` if fixed.
+    #[inline(never)]
     fn drop(&mut self) {
         let b = self.take();
         (b.drop)(b);

std/src/lib.rs

@@ -273,12 +273,12 @@
 //
 // Language features:
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(c_unwind))]
 #![feature(alloc_error_handler)]
 #![feature(allocator_internals)]
 #![feature(allow_internal_unsafe)]
 #![feature(allow_internal_unstable)]
 #![feature(asm_experimental_arch)]
-#![feature(c_unwind)]
 #![feature(cfg_sanitizer_cfi)]
 #![feature(cfg_target_thread_local)]
 #![feature(cfi_encoding)]

unwind/src/lib.rs

@@ -2,7 +2,7 @@
 #![unstable(feature = "panic_unwind", issue = "32837")]
 #![feature(link_cfg)]
 #![feature(staged_api)]
-#![feature(c_unwind)]
+#![cfg_attr(bootstrap, feature(c_unwind))]
 #![feature(strict_provenance)]
 #![cfg_attr(target_arch = "wasm64", feature(simd_wasm64))]
 #![cfg_attr(not(target_env = "msvc"), feature(libc))]