remove support for rustc_safe_intrinsic attribute; use rustc_intrinsic functions instead

Author: RalfJung

compiler/rustc_codegen_gcc/tests/run/slice.rs

@@ -103,9 +103,11 @@ fn panic_bounds_check(index: usize, len: usize) -> ! {
 mod intrinsics {
     use super::Sized;
 
-    extern "rust-intrinsic" {
-        #[rustc_safe_intrinsic]
-        pub fn abort() -> !;
+    #[rustc_nounwind]
+    #[rustc_intrinsic]
+    #[rustc_intrinsic_must_be_overridden]
+    pub fn abort() -> ! {
+        loop {}
     }
 }
 

compiler/rustc_codegen_gcc/tests/run/static.rs

@@ -46,9 +46,11 @@ pub(crate) unsafe auto trait Freeze {}
 mod intrinsics {
     use super::Sized;
 
-    extern "rust-intrinsic" {
-        #[rustc_safe_intrinsic]
-        pub fn abort() -> !;
+    #[rustc_nounwind]
+    #[rustc_intrinsic]
+    #[rustc_intrinsic_must_be_overridden]
+    pub fn abort() -> ! {
+        loop {}
     }
 }