src/librustc_trans/trans/mir/constant.rs

   1 // Copyright 2012-2014 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 use back::abi;
  12 use llvm::ValueRef;
  13 use middle::subst::Substs;
  14 use middle::ty::{Ty, TypeFoldable};
  15 use rustc::middle::const_eval::ConstVal;
  16 use rustc::mir::repr as mir;
  17 use trans::common::{self, Block, C_bool, C_bytes, C_floating_f64, C_integral, C_str_slice};
  18 use trans::consts;
  19 use trans::expr;
  20 use trans::type_of;
  21
  22 use super::operand::{OperandRef, OperandValue};
  23 use super::MirContext;
  24
  25
  26 impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
  27     pub fn trans_constval(&mut self,
  28                           bcx: Block<'bcx, 'tcx>,
  29                           cv: &ConstVal,
  30                           ty: Ty<'tcx>)
  31                           -> OperandRef<'tcx>
  32     {
  33         let ccx = bcx.ccx();
  34         let val = self.trans_constval_inner(bcx, cv, ty, bcx.fcx.param_substs);
  35         let val = if common::type_is_immediate(ccx, ty) {
  36             OperandValue::Immediate(val)
  37         } else if common::type_is_fat_ptr(bcx.tcx(), ty) {
  38             let data = common::const_get_elt(ccx, val, &[abi::FAT_PTR_ADDR as u32]);
  39             let extra = common::const_get_elt(ccx, val, &[abi::FAT_PTR_EXTRA as u32]);
  40             OperandValue::FatPtr(data, extra)
  41         } else {
  42             OperandValue::Ref(val)
  43         };
  44
  45         assert!(!ty.has_erasable_regions());
  46
  47         OperandRef {
  48             ty: ty,
  49             val: val
  50         }
  51     }
  52
  53     /// Translate ConstVal into a bare LLVM ValueRef.
  54     fn trans_constval_inner(&mut self,
  55                             bcx: common::Block<'bcx, 'tcx>,
  56                             cv: &ConstVal,
  57                             ty: Ty<'tcx>,
  58                             param_substs: &'tcx Substs<'tcx>)
  59                             -> ValueRef
  60     {
  61         let ccx = bcx.ccx();
  62         let llty = type_of::type_of(ccx, ty);
  63         match *cv {
  64             ConstVal::Float(v) => C_floating_f64(v, llty),
  65             ConstVal::Bool(v) => C_bool(ccx, v),
  66             ConstVal::Int(v) => C_integral(llty, v as u64, true),
  67             ConstVal::Uint(v) => C_integral(llty, v, false),
  68             ConstVal::Str(ref v) => C_str_slice(ccx, v.clone()),
  69             ConstVal::ByteStr(ref v) => consts::addr_of(ccx, C_bytes(ccx, v), 1, "byte_str"),
  70             ConstVal::Struct(id) | ConstVal::Tuple(id) |
  71             ConstVal::Array(id, _) | ConstVal::Repeat(id, _) => {
  72                 let expr = bcx.tcx().map.expect_expr(id);
  73                 expr::trans(bcx, expr).datum.val
  74             },
  75             ConstVal::Function(did) =>
  76                 self.trans_fn_ref(bcx, ty, param_substs, did).immediate()
  77         }
  78     }
  79
  80     pub fn trans_constant(&mut self,
  81                           bcx: Block<'bcx, 'tcx>,
  82                           constant: &mir::Constant<'tcx>)
  83                           -> OperandRef<'tcx>
  84     {
  85         let ty = bcx.monomorphize(&constant.ty);
  86         match constant.literal {
  87             mir::Literal::Item { def_id, kind, substs } => {
  88                 let substs = bcx.tcx().mk_substs(bcx.monomorphize(&substs));
  89                 self.trans_item_ref(bcx, ty, kind, substs, def_id)
  90             }
  91             mir::Literal::Value { ref value } => {
  92                 self.trans_constval(bcx, value, ty)
  93             }
  94         }
  95     }
  96 }