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Auto merge of #30337 - wesleywiser:mir_switch, r=nikomatsakis

Fixes #29574
This commit is contained in:
bors 2015-12-16 16:10:26 +00:00
commit 073b0f9b85
2 changed files with 71 additions and 2 deletions

View file

@ -10,6 +10,7 @@
use llvm::BasicBlockRef;
use rustc::mir::repr as mir;
use trans::adt;
use trans::base;
use trans::build;
use trans::common::Block;
@ -46,8 +47,28 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
build::CondBr(bcx, cond.immediate(), lltrue, llfalse, DebugLoc::None);
}
mir::Terminator::Switch { .. } => {
unimplemented!()
mir::Terminator::Switch { ref discr, ref adt_def, ref targets } => {
let adt_ty = bcx.tcx().lookup_item_type(adt_def.did).ty;
let represented_ty = adt::represent_type(bcx.ccx(), adt_ty);
let discr_lvalue = self.trans_lvalue(bcx, discr);
let discr = adt::trans_get_discr(bcx, &represented_ty, discr_lvalue.llval, None);
// The else branch of the Switch can't be hit, so branch to an unreachable
// instruction so LLVM knows that
// FIXME it might be nice to have just one such block (created lazilly), we could
// store it in the "MIR trans" state.
let unreachable_blk = bcx.fcx.new_temp_block("enum-variant-unreachable");
build::Unreachable(unreachable_blk);
let switch = build::Switch(bcx, discr, unreachable_blk.llbb, targets.len());
assert_eq!(adt_def.variants.len(), targets.len());
for (adt_variant, target) in adt_def.variants.iter().zip(targets) {
let llval = adt::trans_case(bcx, &*represented_ty, adt_variant.disr_val);
let llbb = self.llblock(*target);
build::AddCase(switch, llval, llbb)
}
}
mir::Terminator::SwitchInt { ref discr, switch_ty, ref values, ref targets } => {

View file

@ -0,0 +1,48 @@
// 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.
#![feature(rustc_attrs)]
enum Abc {
A(u8),
B(i8),
C,
D,
}
#[rustc_mir]
fn foo(x: Abc) -> i32 {
match x {
Abc::C => 3,
Abc::D => 4,
Abc::B(_) => 2,
Abc::A(_) => 1,
}
}
#[rustc_mir]
fn foo2(x: Abc) -> bool {
match x {
Abc::D => true,
_ => false
}
}
fn main() {
assert_eq!(1, foo(Abc::A(42)));
assert_eq!(2, foo(Abc::B(-100)));
assert_eq!(3, foo(Abc::C));
assert_eq!(4, foo(Abc::D));
assert_eq!(false, foo2(Abc::A(1)));
assert_eq!(false, foo2(Abc::B(2)));
assert_eq!(false, foo2(Abc::C));
assert_eq!(true, foo2(Abc::D));
}