Auto merge of #36406 - arielb1:constant-padding, r=eddyb

use `adt::trans_const` when translating constant closures and tuples

The previous way dropped padding on the floor.

Fixes #36401

r? @eddyb

src/librustc_trans/mir/constant.rs

@@ -38,6 +38,7 @@ use value::Value;
 use syntax::ast;
 use syntax_pos::{Span, DUMMY_SP};
 
+use std::fmt;
 use std::ptr;
 
 use super::operand::{OperandRef, OperandValue};
@@ -149,6 +150,12 @@ impl<'tcx> Const<'tcx> {
     }
 }
 
+impl<'tcx> fmt::Debug for Const<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Const({:?}: {:?})", Value(self.llval), self.ty)
+    }
+}
+
 #[derive(Copy, Clone)]
 enum Base {
     /// A constant value without an unique address.
@@ -472,7 +479,8 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
 
     fn const_operand(&self, operand: &mir::Operand<'tcx>, span: Span)
                      -> Result<Const<'tcx>, ConstEvalErr> {
-        match *operand {
+        debug!("const_operand({:?} @ {:?})", operand, span);
+        let result = match *operand {
             mir::Operand::Consume(ref lvalue) => {
                 Ok(self.const_lvalue(lvalue, span)?.to_const(span))
             }
@@ -501,29 +509,41 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
                     }
                 }
             }
-        }
+        };
+        debug!("const_operand({:?} @ {:?}) = {:?}", operand, span,
+               result.as_ref().ok());
+        result
+    }
+
+    fn const_array(&self, array_ty: Ty<'tcx>, fields: &[ValueRef])
+                   -> Const<'tcx>
+    {
+        let elem_ty = array_ty.builtin_index().unwrap_or_else(|| {
+            bug!("bad array type {:?}", array_ty)
+        });
+        let llunitty = type_of::type_of(self.ccx, elem_ty);
+        // If the array contains enums, an LLVM array won't work.
+        let val = if fields.iter().all(|&f| val_ty(f) == llunitty) {
+            C_array(llunitty, fields)
+        } else {
+            C_struct(self.ccx, fields, false)
+        };
+        Const::new(val, array_ty)
     }
 
     fn const_rvalue(&self, rvalue: &mir::Rvalue<'tcx>,
                     dest_ty: Ty<'tcx>, span: Span)
                     -> Result<Const<'tcx>, ConstEvalErr> {
         let tcx = self.ccx.tcx();
+        debug!("const_rvalue({:?}: {:?} @ {:?})", rvalue, dest_ty, span);
         let val = match *rvalue {
             mir::Rvalue::Use(ref operand) => self.const_operand(operand, span)?,
 
             mir::Rvalue::Repeat(ref elem, ref count) => {
                 let elem = self.const_operand(elem, span)?;
                 let size = count.value.as_u64(tcx.sess.target.uint_type);
                 let fields = vec![elem.llval; size as usize];
-
-                let llunitty = type_of::type_of(self.ccx, elem.ty);
-                // If the array contains enums, an LLVM array won't work.
-                let val = if val_ty(elem.llval) == llunitty {
-                    C_array(llunitty, &fields)
-                } else {
-                    C_struct(self.ccx, &fields, false)
-                };
-                Const::new(val, dest_ty)
+                self.const_array(dest_ty, &fields)
             }
 
             mir::Rvalue::Aggregate(ref kind, ref operands) => {
@@ -547,22 +567,26 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
                                                         self.monomorphize(&substs));
                 }
 
-                let val = if let mir::AggregateKind::Adt(adt_def, index, _, _) = *kind {
-                    let repr = adt::represent_type(self.ccx, dest_ty);
-                    let disr = Disr::from(adt_def.variants[index].disr_val);
-                    adt::trans_const(self.ccx, &repr, disr, &fields)
-                } else if let ty::TyArray(elem_ty, _) = dest_ty.sty {
-                    let llunitty = type_of::type_of(self.ccx, elem_ty);
-                    // If the array contains enums, an LLVM array won't work.
-                    if fields.iter().all(|&f| val_ty(f) == llunitty) {
-                        C_array(llunitty, &fields)
-                    } else {
-                        C_struct(self.ccx, &fields, false)
+                match *kind {
+                    mir::AggregateKind::Vec => {
+                        self.const_array(dest_ty, &fields)
                     }
-                } else {
-                    C_struct(self.ccx, &fields, false)
-                };
-                Const::new(val, dest_ty)
+                    mir::AggregateKind::Adt(..) |
+                    mir::AggregateKind::Closure(..) |
+                    mir::AggregateKind::Tuple => {
+                        let disr = match *kind {
+                            mir::AggregateKind::Adt(adt_def, index, _, _) => {
+                                Disr::from(adt_def.variants[index].disr_val)
+                            }
+                            _ => Disr(0)
+                        };
+                        let repr = adt::represent_type(self.ccx, dest_ty);
+                        Const::new(
+                            adt::trans_const(self.ccx, &repr, disr, &fields),
+                            dest_ty
+                        )
+                    }
+                }
             }
 
             mir::Rvalue::Cast(ref kind, ref source, cast_ty) => {
@@ -786,6 +810,8 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
             _ => span_bug!(span, "{:?} in constant", rvalue)
         };
 
+        debug!("const_rvalue({:?}: {:?} @ {:?}) = {:?}", rvalue, dest_ty, span, val);
+
         Ok(val)
     }
 
@@ -935,6 +961,7 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
                           constant: &mir::Constant<'tcx>)
                           -> Const<'tcx>
     {
+        debug!("trans_constant({:?})", constant);
         let ty = bcx.monomorphize(&constant.ty);
         let result = match constant.literal.clone() {
             mir::Literal::Item { def_id, substs } => {
@@ -959,11 +986,14 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
             }
         };
 
-        result.unwrap_or_else(|_| {
+        let result = result.unwrap_or_else(|_| {
             // We've errored, so we don't have to produce working code.
             let llty = type_of::type_of(bcx.ccx(), ty);
             Const::new(C_undef(llty), ty)
-        })
+        });
+
+        debug!("trans_constant({:?}) = {:?}", constant, result);
+        result
     }
 }
 

src/test/run-pass/issue-36401.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.
+
+#[derive(Debug)]
+pub enum Event {
+    Key(u8),
+    Resize,
+    Unknown(u16),
+}
+
+static XTERM_SINGLE_BYTES : [(u8, Event); 1] = [(1,  Event::Resize)];
+
+fn main() {
+    match XTERM_SINGLE_BYTES[0] {
+        (1, Event::Resize) => {},
+        ref bad => panic!("unexpected {:?}", bad)
+    }
+}