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::mir::*;
  18
  19 impl<'tcx> CFG<'tcx> {
  20     pub fn block_data(&self, blk: BasicBlock) -> &BasicBlockData<'tcx> {
  21         &self.basic_blocks[blk]
  22     }
  23
  24     pub fn block_data_mut(&mut self, blk: BasicBlock) -> &mut BasicBlockData<'tcx> {
  25         &mut self.basic_blocks[blk]
  26     }
  27
  28     // llvm.org/PR32488 makes this function use an excess of stack space. Mark
  29     // it as #[inline(never)] to keep rustc's stack use in check.
  30     #[inline(never)]
  31     pub fn start_new_block(&mut self) -> BasicBlock {
  32         self.basic_blocks.push(BasicBlockData::new(None))
  33     }
  34
  35     pub fn start_new_cleanup_block(&mut self) -> BasicBlock {
  36         let bb = self.start_new_block();
  37         self.block_data_mut(bb).is_cleanup = true;
  38         bb
  39     }
  40
  41     pub fn push(&mut self, block: BasicBlock, statement: Statement<'tcx>) {
  42         debug!("push({:?}, {:?})", block, statement);
  43         self.block_data_mut(block).statements.push(statement);
  44     }
  45
  46     pub fn push_assign(&mut self,
  47                        block: BasicBlock,
  48                        source_info: SourceInfo,
  49                        lvalue: &Lvalue<'tcx>,
  50                        rvalue: Rvalue<'tcx>) {
  51         self.push(block, Statement {
  52             source_info: source_info,
  53             kind: StatementKind::Assign(lvalue.clone(), rvalue)
  54         });
  55     }
  56
  57     pub fn push_assign_constant(&mut self,
  58                                 block: BasicBlock,
  59                                 source_info: SourceInfo,
  60                                 temp: &Lvalue<'tcx>,
  61                                 constant: Constant<'tcx>) {
  62         self.push_assign(block, source_info, temp,
  63                          Rvalue::Use(Operand::Constant(constant)));
  64     }
  65
  66     pub fn push_assign_unit(&mut self,
  67                             block: BasicBlock,
  68                             source_info: SourceInfo,
  69                             lvalue: &Lvalue<'tcx>) {
  70         self.push_assign(block, source_info, lvalue, Rvalue::Aggregate(
  71             AggregateKind::Tuple, vec![]
  72         ));
  73     }
  74
  75     pub fn terminate(&mut self,
  76                      block: BasicBlock,
  77                      source_info: SourceInfo,
  78                      kind: TerminatorKind<'tcx>) {
  79         debug!("terminating block {:?} <- {:?}", block, kind);
  80         debug_assert!(self.block_data(block).terminator.is_none(),
  81                       "terminate: block {:?}={:?} already has a terminator set",
  82                       block,
  83                       self.block_data(block));
  84         self.block_data_mut(block).terminator = Some(Terminator {
  85             source_info: source_info,
  86             kind: kind,
  87         });
  88     }
  89 }