Auto merge of #119760 - matthiaskrgr:rollup-ti2xpp7, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #117744 (Add -Zuse-sync-unwind)
 - #118649 (Make inductive cycles in coherence ambiguous always)
 - #118979 (Use `assert_unsafe_precondition` for `char::from_u32_unchecked`)
 - #119619 (mir-opt and custom target fixes)
 - #119632 (Fix broken build for ESP IDF due to #119026)
 - #119712 (Adding alignment to the cases to test for specific error messages.)
 - #119734 (Miri subtree update)

r? `@ghost`
`@rustbot` modify labels: rollup

2 files changed, 6 insertions, 4 deletions

diff --git a/compiler/rustc_codegen_llvm/src/allocator.rs b/compiler/rustc_codegen_llvm/src/allocator.rs
index 58b3aa438c5..ca376029735 100644
--- a/compiler/rustc_codegen_llvm/src/allocator.rs
+++ b/compiler/rustc_codegen_llvm/src/allocator.rs
@@ -134,7 +134,8 @@ fn create_wrapper_function(
             llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
         }
         if tcx.sess.must_emit_unwind_tables() {
-            let uwtable = attributes::uwtable_attr(llcx);
+            let uwtable =
+                attributes::uwtable_attr(llcx, tcx.sess.opts.unstable_opts.use_sync_unwind);
             attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]);
         }
 
diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index b3fa7b7cd44..0a7ea599431 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -95,11 +95,12 @@ pub fn sanitize_attrs<'ll>(
 
 /// Tell LLVM to emit or not emit the information necessary to unwind the stack for the function.
 #[inline]
-pub fn uwtable_attr(llcx: &llvm::Context) -> &Attribute {
+pub fn uwtable_attr(llcx: &llvm::Context, use_sync_unwind: Option<bool>) -> &Attribute {
     // NOTE: We should determine if we even need async unwind tables, as they
     // take have more overhead and if we can use sync unwind tables we
     // probably should.
-    llvm::CreateUWTableAttr(llcx, true)
+    let async_unwind = !use_sync_unwind.unwrap_or(false);
+    llvm::CreateUWTableAttr(llcx, async_unwind)
 }
 
 pub fn frame_pointer_type_attr<'ll>(cx: &CodegenCx<'ll, '_>) -> Option<&'ll Attribute> {
@@ -333,7 +334,7 @@ pub fn from_fn_attrs<'ll, 'tcx>(
     // You can also find more info on why Windows always requires uwtables here:
     //      https://bugzilla.mozilla.org/show_bug.cgi?id=1302078
     if cx.sess().must_emit_unwind_tables() {
-        to_add.push(uwtable_attr(cx.llcx));
+        to_add.push(uwtable_attr(cx.llcx, cx.sess().opts.unstable_opts.use_sync_unwind));
     }
 
     if cx.sess().opts.unstable_opts.profile_sample_use.is_some() {