From fa4a37759be06c2b96c133cfc0f85b7cf2ce00b4 Mon Sep 17 00:00:00 2001
From: bjorn3 <bjorn3@users.noreply.github.com>
Date: Wed, 22 Aug 2018 17:58:25 +0200
Subject: [PATCH] Rvalue::Len

---
 src/base.rs   | 10 +++++++++-
 src/common.rs | 15 ++++++---------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/src/base.rs b/src/base.rs
index 9b44cd2e4b73..c0ea7644f903 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -474,7 +474,15 @@ fn trans_stmt<'a, 'tcx: 'a>(
                         to.write_cvalue(fx, operand);
                     }
                 }
-                Rvalue::Len(lval) => unimpl!("rval len {:?}", lval),
+                Rvalue::Len(place) => {
+                    let place = trans_place(fx, place);
+                    let size = match place {
+                        CPlace::Addr(_, size, _) => size.unwrap(),
+                        CPlace::Var(_, _) => unreachable!(),
+                    };
+                    let usize_layout = fx.layout_of(fx.tcx.types.usize);
+                    lval.write_cvalue(fx, CValue::ByVal(size, usize_layout));
+                }
                 Rvalue::NullaryOp(NullOp::Box, ty) => unimplemented!("rval box {:?}", ty),
                 Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
                     assert!(
diff --git a/src/common.rs b/src/common.rs
index b785177251fa..9bd3e823fcb3 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -433,23 +433,20 @@ impl<'a, 'tcx: 'a> CPlace<'tcx> {
         fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
         index: Value,
     ) -> CPlace<'tcx> {
-        let addr = self.expect_addr();
-        let layout = self.layout();
-        if layout.is_unsized() {
-            unimpl!("unsized place_field");
-        }
-
-        match layout.ty.sty {
+        match self.layout().ty.sty {
             ty::Array(elem_ty, _) => {
                 let elem_layout = fx.layout_of(elem_ty);
+
                 let offset = fx
                     .bcx
                     .ins()
                     .imul_imm(index, elem_layout.size.bytes() as i64);
+
+                let addr = self.expect_addr();
                 CPlace::Addr(fx.bcx.ins().iadd(addr, offset), None, elem_layout)
             }
-            ty::Slice(_elem_ty) => unimplemented!("place_index(TySlice)"),
-            _ => bug!("place_index({:?})", layout.ty),
+            ty::Slice(_elem_ty) => unimpl!("place_index(TySlice)"),
+            _ => bug!("place_index({:?})", self.layout().ty),
         }
     }