src/librustc_mir/tcx/mod.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 /*!
  12  * Methods for the various MIR types. These are intended for use after
  13  * building is complete.
  14  */
  15
  16 use repr::*;
  17 use rustc::middle::subst::Substs;
  18 use rustc::middle::ty::{self, AdtDef, Ty};
  19 use rustc_front::hir;
  20
  21 #[derive(Copy, Clone, Debug)]
  22 pub enum LvalueTy<'tcx> {
  23     /// Normal type.
  24     Ty { ty: Ty<'tcx> },
  25
  26     /// Downcast to a particular variant of an enum.
  27     Downcast { adt_def: AdtDef<'tcx>,
  28                substs: &'tcx Substs<'tcx>,
  29                variant_index: usize },
  30 }
  31
  32 impl<'tcx> LvalueTy<'tcx> {
  33     pub fn from_ty(ty: Ty<'tcx>) -> LvalueTy<'tcx> {
  34         LvalueTy::Ty { ty: ty }
  35     }
  36
  37     pub fn to_ty(&self, tcx: &ty::ctxt<'tcx>) -> Ty<'tcx> {
  38         match *self {
  39             LvalueTy::Ty { ty } =>
  40                 ty,
  41             LvalueTy::Downcast { adt_def, substs, variant_index: _ } =>
  42                 tcx.mk_enum(adt_def, substs),
  43         }
  44     }
  45
  46     pub fn projection_ty(self,
  47                          tcx: &ty::ctxt<'tcx>,
  48                          elem: &LvalueElem<'tcx>)
  49                          -> LvalueTy<'tcx>
  50     {
  51         match *elem {
  52             ProjectionElem::Deref =>
  53                 LvalueTy::Ty {
  54                     ty: self.to_ty(tcx).builtin_deref(true, ty::LvaluePreference::NoPreference)
  55                                           .unwrap()
  56                                           .ty
  57                 },
  58             ProjectionElem::Index(_) | ProjectionElem::ConstantIndex { .. } =>
  59                 LvalueTy::Ty {
  60                     ty: self.to_ty(tcx).builtin_index().unwrap()
  61                 },
  62             ProjectionElem::Downcast(adt_def1, index) =>
  63                 match self.to_ty(tcx).sty {
  64                     ty::TyEnum(adt_def, substs) => {
  65                         assert!(index < adt_def.variants.len());
  66                         assert_eq!(adt_def, adt_def1);
  67                         LvalueTy::Downcast { adt_def: adt_def,
  68                                              substs: substs,
  69                                              variant_index: index }
  70                     }
  71                     _ => {
  72                         tcx.sess.bug(&format!("cannot downcast non-enum type: `{:?}`", self))
  73                     }
  74                 },
  75             ProjectionElem::Field(field) => {
  76                 let field_ty = match self {
  77                     LvalueTy::Ty { ty } => match ty.sty {
  78                         ty::TyStruct(adt_def, substs) =>
  79                             adt_def.struct_variant().fields[field.index()].ty(tcx, substs),
  80                         ty::TyTuple(ref tys) =>
  81                             tys[field.index()],
  82                         ty::TyClosure(_, ref closure_substs) =>
  83                             closure_substs.upvar_tys[field.index()],
  84                         _ =>
  85                             tcx.sess.bug(&format!("cannot get field of type: `{:?}`", ty)),
  86                     },
  87                     LvalueTy::Downcast { adt_def, substs, variant_index } =>
  88                         adt_def.variants[variant_index].fields[field.index()].ty(tcx, substs),
  89                 };
  90                 LvalueTy::Ty { ty: field_ty }
  91             }
  92         }
  93     }
  94 }
  95
  96 impl<'tcx> Mir<'tcx> {
  97     pub fn operand_ty(&self,
  98                       tcx: &ty::ctxt<'tcx>,
  99                       operand: &Operand<'tcx>)
 100                       -> Ty<'tcx>
 101     {
 102         match *operand {
 103             Operand::Consume(ref l) => self.lvalue_ty(tcx, l).to_ty(tcx),
 104             Operand::Constant(ref c) => c.ty,
 105         }
 106     }
 107
 108     pub fn binop_ty(&self,
 109                     tcx: &ty::ctxt<'tcx>,
 110                     op: BinOp,
 111                     lhs_ty: Ty<'tcx>,
 112                     rhs_ty: Ty<'tcx>)
 113                     -> Ty<'tcx>
 114     {
 115         // FIXME: handle SIMD correctly
 116         match op {
 117             BinOp::Add | BinOp::Sub | BinOp::Mul | BinOp::Div | BinOp::Rem |
 118             BinOp::BitXor | BinOp::BitAnd | BinOp::BitOr => {
 119                 // these should be integers or floats of the same size.
 120                 assert_eq!(lhs_ty, rhs_ty);
 121                 lhs_ty
 122             }
 123             BinOp::Shl | BinOp::Shr => {
 124                 lhs_ty // lhs_ty can be != rhs_ty
 125             }
 126             BinOp::Eq | BinOp::Lt | BinOp::Le |
 127             BinOp::Ne | BinOp::Ge | BinOp::Gt => {
 128                 tcx.types.bool
 129             }
 130         }
 131     }
 132
 133     pub fn lvalue_ty(&self,
 134                      tcx: &ty::ctxt<'tcx>,
 135                      lvalue: &Lvalue<'tcx>)
 136                      -> LvalueTy<'tcx>
 137     {
 138         match *lvalue {
 139             Lvalue::Var(index) =>
 140                 LvalueTy::Ty { ty: self.var_decls[index as usize].ty },
 141             Lvalue::Temp(index) =>
 142                 LvalueTy::Ty { ty: self.temp_decls[index as usize].ty },
 143             Lvalue::Arg(index) =>
 144                 LvalueTy::Ty { ty: self.arg_decls[index as usize].ty },
 145             Lvalue::Static(def_id) =>
 146                 LvalueTy::Ty { ty: tcx.lookup_item_type(def_id).ty },
 147             Lvalue::ReturnPointer =>
 148                 LvalueTy::Ty { ty: self.return_ty.unwrap() },
 149             Lvalue::Projection(ref proj) =>
 150                 self.lvalue_ty(tcx, &proj.base).projection_ty(tcx, &proj.elem)
 151         }
 152     }
 153 }
 154
 155 impl BorrowKind {
 156     pub fn to_mutbl_lossy(self) -> hir::Mutability {
 157         match self {
 158             BorrowKind::Mut => hir::MutMutable,
 159             BorrowKind::Shared => hir::MutImmutable,
 160
 161             // We have no type corresponding to a unique imm borrow, so
 162             // use `&mut`. It gives all the capabilities of an `&uniq`
 163             // and hence is a safe "over approximation".
 164             BorrowKind::Unique => hir::MutMutable,
 165         }
 166     }
 167 }
 168
 169 impl BinOp {
 170     pub fn to_hir_binop(self) -> hir::BinOp_ {
 171         match self {
 172             BinOp::Add => hir::BinOp_::BiAdd,
 173             BinOp::Sub => hir::BinOp_::BiSub,
 174             BinOp::Mul => hir::BinOp_::BiMul,
 175             BinOp::Div => hir::BinOp_::BiDiv,
 176             BinOp::Rem => hir::BinOp_::BiRem,
 177             BinOp::BitXor => hir::BinOp_::BiBitXor,
 178             BinOp::BitAnd => hir::BinOp_::BiBitAnd,
 179             BinOp::BitOr => hir::BinOp_::BiBitOr,
 180             BinOp::Shl => hir::BinOp_::BiShl,
 181             BinOp::Shr => hir::BinOp_::BiShr,
 182             BinOp::Eq => hir::BinOp_::BiEq,
 183             BinOp::Ne => hir::BinOp_::BiNe,
 184             BinOp::Lt => hir::BinOp_::BiLt,
 185             BinOp::Gt => hir::BinOp_::BiGt,
 186             BinOp::Le => hir::BinOp_::BiLe,
 187             BinOp::Ge => hir::BinOp_::BiGe
 188         }
 189     }
 190 }