More work on miri_start_panic

src/libcore/intrinsics.rs

@@ -1352,7 +1352,12 @@ extern "rust-intrinsic" {
     /// Internal hook used by Miri to implement unwinding.
     /// Perma-unstable: do not use
     #[cfg(not(bootstrap))]
-    pub fn miri_start_panic(data: u128) -> !;
+    // Note that the type is data is pretty arbitrary:
+    // we just need something that's guarnateed to be a fat
+    // pointer. Using `*mut [()]` instead of the actual type
+    // `*mut (Any + Send)` allows us to avoid making `Any` and `Send`
+    // lang items
+    pub fn miri_start_panic(data: *mut [()]) -> !;
 }
 
 // Some functions are defined here because they accidentally got made

src/libpanic_unwind/miri.rs

@@ -6,7 +6,7 @@ pub fn payload() -> *mut u8 {
 }
 
 pub unsafe fn panic(data: Box<dyn Any + Send>) -> ! {
-    let raw_val = core::mem::transmute::<_, u128>(Box::into_raw(data));
+    let raw_val: *mut [()] = core::mem::transmute::<*mut (dyn Any + Send), _>(Box::into_raw(data));
     core::intrinsics::miri_start_panic(raw_val)
 }
 
@@ -14,3 +14,11 @@ pub unsafe fn cleanup(ptr: *mut u8) -> Box<dyn Any + Send> {
     Box::from_raw(ptr)
 }
 
+
+// This is required by the compiler to exist (e.g., it's a lang item),
+// but is never used by Miri. Therefore, we just use a stub here
+#[lang = "eh_personality"]
+#[cfg(not(test))]
+fn rust_eh_personality() {
+    unsafe { core::intrinsics::abort() }
+}

src/librustc_typeck/check/intrinsic.rs

@@ -385,7 +385,7 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem) {
             }
 
             "miri_start_panic" => {
-                (0, vec![tcx.types.u128], tcx.types.never)
+                (0, vec![tcx.mk_mut_ptr(tcx.mk_slice(tcx.mk_unit()))], tcx.types.never)
             }
 
             ref other => {