src/librustc_passes/rvalues.rs

   1 // Copyright 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 // Checks that all rvalues in a crate have statically known size. check_crate
  12 // is the public starting point.
  13
  14 use rustc::dep_graph::DepNode;
  15 use rustc::middle::expr_use_visitor as euv;
  16 use rustc::middle::mem_categorization as mc;
  17 use rustc::ty::{self, TyCtxt, ParameterEnvironment};
  18 use rustc::traits::Reveal;
  19
  20 use rustc::hir;
  21 use rustc::hir::intravisit;
  22 use syntax::ast;
  23 use syntax_pos::Span;
  24
  25 pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
  26     let mut rvcx = RvalueContext { tcx: tcx };
  27     tcx.visit_all_items_in_krate(DepNode::RvalueCheck, &mut rvcx);
  28 }
  29
  30 struct RvalueContext<'a, 'tcx: 'a> {
  31     tcx: TyCtxt<'a, 'tcx, 'tcx>,
  32 }
  33
  34 impl<'a, 'tcx, 'v> intravisit::Visitor<'v> for RvalueContext<'a, 'tcx> {
  35     fn visit_fn(&mut self,
  36                 fk: intravisit::FnKind<'v>,
  37                 fd: &'v hir::FnDecl,
  38                 b: &'v hir::Block,
  39                 s: Span,
  40                 fn_id: ast::NodeId) {
  41         // FIXME (@jroesch) change this to be an inference context
  42         let param_env = ParameterEnvironment::for_item(self.tcx, fn_id);
  43         self.tcx.infer_ctxt(None, Some(param_env.clone()),
  44                             Reveal::NotSpecializable).enter(|infcx| {
  45             let mut delegate = RvalueContextDelegate {
  46                 tcx: infcx.tcx,
  47                 param_env: &param_env
  48             };
  49             let mut euv = euv::ExprUseVisitor::new(&mut delegate, &infcx);
  50             euv.walk_fn(fd, b);
  51         });
  52         intravisit::walk_fn(self, fk, fd, b, s, fn_id)
  53     }
  54 }
  55
  56 struct RvalueContextDelegate<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
  57     tcx: TyCtxt<'a, 'gcx, 'tcx>,
  58     param_env: &'a ty::ParameterEnvironment<'gcx>,
  59 }
  60
  61 impl<'a, 'gcx, 'tcx> euv::Delegate<'tcx> for RvalueContextDelegate<'a, 'gcx, 'tcx> {
  62     fn consume(&mut self,
  63                _: ast::NodeId,
  64                span: Span,
  65                cmt: mc::cmt<'tcx>,
  66                _: euv::ConsumeMode) {
  67         debug!("consume; cmt: {:?}; type: {:?}", *cmt, cmt.ty);
  68         let ty = self.tcx.lift_to_global(&cmt.ty).unwrap();
  69         if !ty.is_sized(self.tcx.global_tcx(), self.param_env, span) {
  70             span_err!(self.tcx.sess, span, E0161,
  71                 "cannot move a value of type {0}: the size of {0} cannot be statically determined",
  72                 ty);
  73         }
  74     }
  75
  76     fn matched_pat(&mut self,
  77                    _matched_pat: &hir::Pat,
  78                    _cmt: mc::cmt,
  79                    _mode: euv::MatchMode) {}
  80
  81     fn consume_pat(&mut self,
  82                    _consume_pat: &hir::Pat,
  83                    _cmt: mc::cmt,
  84                    _mode: euv::ConsumeMode) {
  85     }
  86
  87     fn borrow(&mut self,
  88               _borrow_id: ast::NodeId,
  89               _borrow_span: Span,
  90               _cmt: mc::cmt,
  91               _loan_region: &'tcx ty::Region,
  92               _bk: ty::BorrowKind,
  93               _loan_cause: euv::LoanCause) {
  94     }
  95
  96     fn decl_without_init(&mut self,
  97                          _id: ast::NodeId,
  98                          _span: Span) {
  99     }
 100
 101     fn mutate(&mut self,
 102               _assignment_id: ast::NodeId,
 103               _assignment_span: Span,
 104               _assignee_cmt: mc::cmt,
 105               _mode: euv::MutateMode) {
 106     }
 107 }