Fix ICE when trying to drop an unsized type from a different crate

The code to get the LLVM type signature for the drop function doesn't
handle unsized types correctly.

src/librustc_trans/trans/type_of.rs

@@ -472,6 +472,9 @@ fn llvm_type_name<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 }
 
 pub fn type_of_dtor<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, self_ty: Ty<'tcx>) -> Type {
-    let self_ty = type_of(ccx, self_ty).ptr_to();
-    Type::func(&[self_ty], &Type::void(ccx))
+    if type_is_sized(ccx.tcx(), self_ty) {
+        Type::func(&[type_of(ccx, self_ty).ptr_to()], &Type::void(ccx))
+    } else {
+        Type::func(&type_of(ccx, self_ty).field_types(), &Type::void(ccx))
+    }
 }

src/test/auxiliary/fat_drop.rs

@@ -0,0 +1,23 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub static mut DROPPED: bool = false;
+
+pub struct S {
+    _unsized: [u8]
+}
+
+impl Drop for S {
+    fn drop(&mut self) {
+        unsafe {
+            DROPPED = true;
+        }
+    }
+}

src/test/run-pass/extern_fat_drop.rs

@@ -0,0 +1,23 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// aux-build:fat_drop.rs
+
+#![feature(core_intrinsics)]
+
+extern crate fat_drop;
+
+fn main() {
+    unsafe {
+        let s: &mut fat_drop::S = std::mem::uninitialized();
+        std::intrinsics::drop_in_place(s);
+        assert!(fat_drop::DROPPED);
+    }
+}