Implement ProjectionElem::ConstantIndex

0006-alloc-Disable-some-unsupported-stuff.patch

@@ -5,7 +5,6 @@ Subject: [PATCH] [alloc] Disable some unsupported stuff
 
 ---
  src/liballoc/boxed.rs | 6 ------
- src/liballoc/str.rs   | 4 ++++
  src/liballoc/vec.rs   | 2 --
  3 files changed, 4 insertions(+), 8 deletions(-)
 
@@ -33,42 +32,6 @@ index f989e70..597dd15 100644
      fn write_isize(&mut self, i: isize) {
          (**self).write_isize(i)
      }
-diff --git a/src/liballoc/str.rs b/src/liballoc/str.rs
-index 2af8956..23dbb79 100644
---- a/src/liballoc/str.rs
-+++ b/src/liballoc/str.rs
-@@ -361,6 +361,7 @@ impl str {
-     #[stable(feature = "unicode_case_mapping", since = "1.2.0")]
-     pub fn to_lowercase(&self) -> String {
-         let mut s = String::with_capacity(self.len());
-+        /*
-         for (i, c) in self[..].char_indices() {
-             if c == 'Σ' {
-                 // Σ maps to σ, except at the end of a word where it maps to ς.
-@@ -384,6 +385,7 @@ impl str {
-                 }
-             }
-         }
-+        */
-         return s;
- 
-         fn map_uppercase_sigma(from: &str, i: usize, to: &mut String) {
-@@ -435,6 +437,7 @@ impl str {
-     #[stable(feature = "unicode_case_mapping", since = "1.2.0")]
-     pub fn to_uppercase(&self) -> String {
-         let mut s = String::with_capacity(self.len());
-+        /*
-         for c in self[..].chars() {
-             match conversions::to_upper(c) {
-                 [a, '\0', _] => s.push(a),
-@@ -449,6 +452,7 @@ impl str {
-                 }
-             }
-         }
-+        */
-         return s;
-     }
- 
 diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
 index 2bc037e..2fe8894 100644
 --- a/src/liballoc/vec.rs
@@ -79,14 +42,13 @@ index 2bc037e..2fe8894 100644
  impl_is_zero!(i64, |x| x == 0);
 -impl_is_zero!(i128, |x| x == 0);
  impl_is_zero!(isize, |x| x == 0);
- 
+
  impl_is_zero!(u16, |x| x == 0);
  impl_is_zero!(u32, |x| x == 0);
  impl_is_zero!(u64, |x| x == 0);
 -impl_is_zero!(u128, |x| x == 0);
  impl_is_zero!(usize, |x| x == 0);
- 
- impl_is_zero!(char, |x| x == '\0');
--- 
-2.17.1 (Apple Git-112)
 
+ impl_is_zero!(char, |x| x == '\0');
+--
+2.17.1 (Apple Git-112)

src/base.rs

@@ -588,18 +588,7 @@ fn trans_stmt<'a, 'tcx: 'a>(
                 Rvalue::Len(place) => {
                     let place = trans_place(fx, place);
                     let usize_layout = fx.layout_of(fx.tcx.types.usize);
-                    let len = match place.layout().ty.sty {
-                        ty::Array(_elem_ty, len) => {
-                            let len = crate::constant::force_eval_const(fx, len)
-                                .unwrap_usize(fx.tcx) as i64;
-                            fx.bcx.ins().iconst(fx.pointer_type, len)
-                        }
-                        ty::Slice(_elem_ty) => match place {
-                            CPlace::Addr(_, size, _) => size.unwrap(),
-                            CPlace::Var(_, _) => unreachable!(),
-                        },
-                        _ => bug!("Rvalue::Len({:?})", place),
-                    };
+                    let len = codegen_array_len(fx, place);
                     lval.write_cvalue(fx, CValue::ByVal(len, usize_layout));
                 }
                 Rvalue::NullaryOp(NullOp::Box, content_ty) => {
@@ -660,6 +649,24 @@ fn trans_stmt<'a, 'tcx: 'a>(
     }
 }
 
+fn codegen_array_len<'a, 'tcx: 'a>(
+    fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
+    place: CPlace<'tcx>,
+) -> Value {
+    match place.layout().ty.sty {
+        ty::Array(_elem_ty, len) => {
+            let len = crate::constant::force_eval_const(fx, len)
+                .unwrap_usize(fx.tcx) as i64;
+            fx.bcx.ins().iconst(fx.pointer_type, len)
+        }
+        ty::Slice(_elem_ty) => match place {
+            CPlace::Addr(_, size, _) => size.unwrap(),
+            CPlace::Var(_, _) => unreachable!(),
+        },
+        _ => bug!("Rvalue::Len({:?})", place),
+    }
+}
+
 pub fn trans_get_discriminant<'a, 'tcx: 'a>(
     fx: &mut FunctionCx<'a, 'tcx, impl Backend>,
     value: CValue<'tcx>,
@@ -1060,21 +1067,16 @@ pub fn trans_place<'a, 'tcx: 'a>(
                 ProjectionElem::ConstantIndex {
                     offset,
                     min_length: _,
-                    from_end: false,
-                } => unimpl!(
-                    "projection const index {:?} offset {:?} not from end",
-                    projection.base,
-                    offset
-                ),
-                ProjectionElem::ConstantIndex {
-                    offset,
-                    min_length: _,
-                    from_end: true,
-                } => unimpl!(
-                    "projection const index {:?} offset {:?} from end",
-                    projection.base,
-                    offset
-                ),
+                    from_end,
+                } => {
+                    let index = if !from_end {
+                        fx.bcx.ins().iconst(fx.pointer_type, offset as i64)
+                    } else {
+                        let len = codegen_array_len(fx, base);
+                        fx.bcx.ins().iadd_imm(len, -(offset as i64))
+                    };
+                    base.place_index(fx, index)
+                },
                 ProjectionElem::Subslice { from, to } => unimpl!(
                     "projection subslice {:?} from {} to {}",
                     projection.base,