Merge pull request rust-lang#128 from oli-obk/align_thyself

fix size of dst in size_of_val intrinsic

Author: solson

src/terminator/intrinsic.rs

@@ -1,6 +1,6 @@
 use rustc::hir::def_id::DefId;
 use rustc::mir;
-use rustc::ty::layout::Layout;
+use rustc::ty::layout::{Layout, Size, Align};
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, Ty};
 
@@ -426,17 +426,14 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
 
                     let (sized_size, sized_align) = match *layout {
                         ty::layout::Layout::Univariant { ref variant, .. } => {
-                            // The offset of the start of the last field gives the size of the
-                            // sized part of the type.
-                            let size = variant.offsets.last().map_or(0, |f| f.bytes());
-                            (size, variant.align.abi())
+                            (variant.offsets.last().map_or(0, |o| o.bytes()), variant.align)
                         }
                         _ => {
                             bug!("size_and_align_of_dst: expcted Univariant for `{}`, found {:#?}",
                                  ty, layout);
                         }
                     };
-                    debug!("DST {} statically sized prefix size: {} align: {}",
+                    debug!("DST {} statically sized prefix size: {} align: {:?}",
                            ty, sized_size, sized_align);
 
                     // Recurse to get the size of the dynamically sized field (must be
@@ -457,7 +454,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
 
                     // Choose max of two known alignments (combined value must
                     // be aligned according to more restrictive of the two).
-                    let align = ::std::cmp::max(sized_align, unsized_align);
+                    let align = sized_align.max(Align::from_bytes(unsized_align, unsized_align).unwrap());
 
                     // Issue #27023: must add any necessary padding to `size`
                     // (to make it a multiple of `align`) before returning it.
@@ -470,11 +467,8 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
                     //
                     //   `(size + (align-1)) & -align`
 
-                    if size & (align - 1) != 0 {
-                        Ok((size + align, align))
-                    } else {
-                        Ok((size, align))
-                    }
+                    let size = Size::from_bytes(size).abi_align(align).bytes();
+                    Ok((size, align.abi()))
                 }
                 ty::TyDynamic(..) => {
                     let (_, vtable) = value.expect_ptr_vtable_pair(&self.memory)?;

tests/run-pass/issue-35815.rs

@@ -0,0 +1,25 @@
+// Copyright 2016 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.
+
+#![allow(dead_code)]
+
+use std::mem;
+
+struct Foo<T: ?Sized> {
+    a: i64,
+    b: bool,
+    c: T,
+}
+
+fn main() {
+    let foo: &Foo<i32> = &Foo { a: 1, b: false, c: 2i32 };
+    let foo_unsized: &Foo<Send> = foo;
+    assert_eq!(mem::size_of_val(foo), mem::size_of_val(foo_unsized));
+}