src/librustc_mir/build/cfg.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
  13
  14 //! Routines for manipulating the control-flow graph.
  15
  16 use build::CFG;
  17 use rustc::middle::region;
  18 use rustc::mir::*;
  19 use rustc::ty;
  20
  21 impl<'tcx> CFG<'tcx> {
  22     pub fn block_data(&self, blk: BasicBlock) -> &BasicBlockData<'tcx> {
  23         &self.basic_blocks[blk]
  24     }
  25
  26     pub fn block_data_mut(&mut self, blk: BasicBlock) -> &mut BasicBlockData<'tcx> {
  27         &mut self.basic_blocks[blk]
  28     }
  29
  30     // llvm.org/PR32488 makes this function use an excess of stack space. Mark
  31     // it as #[inline(never)] to keep rustc's stack use in check.
  32     #[inline(never)]
  33     pub fn start_new_block(&mut self) -> BasicBlock {
  34         self.basic_blocks.push(BasicBlockData::new(None))
  35     }
  36
  37     pub fn start_new_cleanup_block(&mut self) -> BasicBlock {
  38         let bb = self.start_new_block();
  39         self.block_data_mut(bb).is_cleanup = true;
  40         bb
  41     }
  42
  43     pub fn push(&mut self, block: BasicBlock, statement: Statement<'tcx>) {
  44         debug!("push({:?}, {:?})", block, statement);
  45         self.block_data_mut(block).statements.push(statement);
  46     }
  47
  48     pub fn push_end_region<'a, 'gcx:'a+'tcx>(&mut self,
  49                                              tcx: ty::TyCtxt<'a, 'gcx, 'tcx>,
  50                                              block: BasicBlock,
  51                                              source_info: SourceInfo,
  52                                              region_scope: region::Scope) {
  53         if tcx.sess.emit_end_regions() {
  54             self.push(block, Statement {
  55                 source_info,
  56                 kind: StatementKind::EndRegion(region_scope),
  57             });
  58         }
  59     }
  60
  61     pub fn push_assign(&mut self,
  62                        block: BasicBlock,
  63                        source_info: SourceInfo,
  64                        lvalue: &Lvalue<'tcx>,
  65                        rvalue: Rvalue<'tcx>) {
  66         self.push(block, Statement {
  67             source_info,
  68             kind: StatementKind::Assign(lvalue.clone(), rvalue)
  69         });
  70     }
  71
  72     pub fn push_assign_constant(&mut self,
  73                                 block: BasicBlock,
  74                                 source_info: SourceInfo,
  75                                 temp: &Lvalue<'tcx>,
  76                                 constant: Constant<'tcx>) {
  77         self.push_assign(block, source_info, temp,
  78                          Rvalue::Use(Operand::Constant(box constant)));
  79     }
  80
  81     pub fn push_assign_unit(&mut self,
  82                             block: BasicBlock,
  83                             source_info: SourceInfo,
  84                             lvalue: &Lvalue<'tcx>) {
  85         self.push_assign(block, source_info, lvalue, Rvalue::Aggregate(
  86             box AggregateKind::Tuple, vec![]
  87         ));
  88     }
  89
  90     pub fn terminate(&mut self,
  91                      block: BasicBlock,
  92                      source_info: SourceInfo,
  93                      kind: TerminatorKind<'tcx>) {
  94         debug!("terminating block {:?} <- {:?}", block, kind);
  95         debug_assert!(self.block_data(block).terminator.is_none(),
  96                       "terminate: block {:?}={:?} already has a terminator set",
  97                       block,
  98                       self.block_data(block));
  99         self.block_data_mut(block).terminator = Some(Terminator {
 100             source_info,
 101             kind,
 102         });
 103     }
 104 }