src/librustc_mir/build/misc.rs

   1 //! Miscellaneous builder routines that are not specific to building any particular
   2 //! kind of thing.
   3
   4 use crate::build::Builder;
   5
   6 use rustc::ty::{self, Ty};
   7
   8 use rustc::mir::*;
   9 use syntax_pos::{Span, DUMMY_SP};
  10
  11 impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
  12     /// Adds a new temporary value of type `ty` storing the result of
  13     /// evaluating `expr`.
  14     ///
  15     /// N.B., **No cleanup is scheduled for this temporary.** You should
  16     /// call `schedule_drop` once the temporary is initialized.
  17     pub fn temp(&mut self, ty: Ty<'tcx>, span: Span) -> Place<'tcx> {
  18         let temp = self.local_decls.push(LocalDecl::new_temp(ty, span));
  19         let place = Place::Local(temp);
  20         debug!("temp: created temp {:?} with type {:?}",
  21                place, self.local_decls[temp].ty);
  22         place
  23     }
  24
  25     /// Convenience function for creating a literal operand, one
  26     /// without any user type annotation.
  27     pub fn literal_operand(&mut self,
  28                            span: Span,
  29                            ty: Ty<'tcx>,
  30                            literal: ty::Const<'tcx>)
  31                            -> Operand<'tcx> {
  32         let constant = box Constant {
  33             span,
  34             ty,
  35             user_ty: None,
  36             literal: self.hir.tcx().mk_lazy_const(ty::LazyConst::Evaluated(literal)),
  37         };
  38         Operand::Constant(constant)
  39     }
  40
  41     pub fn unit_rvalue(&mut self) -> Rvalue<'tcx> {
  42         Rvalue::Aggregate(box AggregateKind::Tuple, vec![])
  43     }
  44
  45     // Returns a zero literal operand for the appropriate type, works for
  46     // bool, char and integers.
  47     pub fn zero_literal(&mut self, span: Span, ty: Ty<'tcx>) -> Operand<'tcx> {
  48         let literal = ty::Const::from_bits(self.hir.tcx(), 0, ty::ParamEnv::empty().and(ty));
  49
  50         self.literal_operand(span, ty, literal)
  51     }
  52
  53     pub fn push_usize(&mut self,
  54                       block: BasicBlock,
  55                       source_info: SourceInfo,
  56                       value: u64)
  57                       -> Place<'tcx> {
  58         let usize_ty = self.hir.usize_ty();
  59         let temp = self.temp(usize_ty, source_info.span);
  60         self.cfg.push_assign_constant(
  61             block, source_info, &temp,
  62             Constant {
  63                 span: source_info.span,
  64                 ty: self.hir.usize_ty(),
  65                 user_ty: None,
  66                 literal: self.hir.usize_literal(value),
  67             });
  68         temp
  69     }
  70
  71     pub fn consume_by_copy_or_move(&self, place: Place<'tcx>) -> Operand<'tcx> {
  72         let tcx = self.hir.tcx();
  73         let ty = place.ty(&self.local_decls, tcx).to_ty(tcx);
  74         if !self.hir.type_is_copy_modulo_regions(ty, DUMMY_SP) {
  75             Operand::Move(place)
  76         } else {
  77             Operand::Copy(place)
  78         }
  79     }
  80 }