llvm: migrate to new parameter-bearing uwtable attr

In https://reviews.llvm.org/D114543 the uwtable attribute gained a flag
so that we can ask for sync uwtables instead of async, as the former are
much cheaper. The default is async, so that's what I've done here, but I
left a TODO that we might be able to do better.

While in here I went ahead and dropped support for removing uwtable
attributes in rustc: we never did it, so I didn't write the extra C++
bridge code to make it work. Maybe I should have done the same thing
with the `sync|async` parameter but we'll see.

1 files changed, 2 insertions, 2 deletions

diff --git a/compiler/rustc_codegen_llvm/src/allocator.rs b/compiler/rustc_codegen_llvm/src/allocator.rs
index 30d91b41a8e..7680d4fd233 100644
--- a/compiler/rustc_codegen_llvm/src/allocator.rs
+++ b/compiler/rustc_codegen_llvm/src/allocator.rs
@@ -64,7 +64,7 @@ pub(crate) unsafe fn codegen(
             llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
         }
         if tcx.sess.must_emit_unwind_tables() {
-            attributes::emit_uwtable(llfn, true);
+            attributes::emit_uwtable(llfn);
         }
 
         let callee = kind.fn_name(method.name);
@@ -111,7 +111,7 @@ pub(crate) unsafe fn codegen(
         llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
     }
     if tcx.sess.must_emit_unwind_tables() {
-        attributes::emit_uwtable(llfn, true);
+        attributes::emit_uwtable(llfn);
     }
 
     let kind = if has_alloc_error_handler { AllocatorKind::Global } else { AllocatorKind::Default };