Use existing declaration of rust_eh_personality

If crate declares `rust_eh_personality`, re-use existing declaration
as otherwise attempts to set function attributes that follow the
declaration will fail (unless it happens to have exactly the same
type signature as the one predefined in the compiler).

1 files changed, 8 insertions, 3 deletions

diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index d1aecd32e2f..cccf2f8498c 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -385,11 +385,16 @@ impl MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                 } else {
                     "rust_eh_personality"
                 };
-                let fty = self.type_variadic_func(&[], self.type_i32());
-                self.declare_cfn(name, llvm::UnnamedAddr::Global, fty)
+                if let Some(llfn) = self.get_declared_value(name) {
+                    llfn
+                } else {
+                    let fty = self.type_variadic_func(&[], self.type_i32());
+                    let llfn = self.declare_cfn(name, llvm::UnnamedAddr::Global, fty);
+                    attributes::apply_target_cpu_attr(self, llfn);
+                    llfn
+                }
             }
         };
-        attributes::apply_target_cpu_attr(self, llfn);
         self.eh_personality.set(Some(llfn));
         llfn
     }