mcs/class/Mono.CodeContracts/Mono.CodeContracts.Static.ControlFlow.Subroutines.Builders/BlockBuilder.cs

   1 //
   2 // BlockBuilder.cs
   3 //
   4 // Authors:
   5 //      Alexander Chebaturkin (chebaturkin@gmail.com)
   6 //
   7 // Copyright (C) 2011 Alexander Chebaturkin
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using Mono.CodeContracts.Static.AST;
  30 using Mono.CodeContracts.Static.AST.Visitors;
  31 using Mono.CodeContracts.Static.ControlFlow.Blocks;
  32 using Mono.CodeContracts.Static.DataStructures;
  33
  34 namespace Mono.CodeContracts.Static.ControlFlow.Subroutines.Builders {
  35         class BlockBuilder<TLabel> : ILVisitorBase<TLabel, Dummy, Dummy, BlockWithLabels<TLabel>, bool>,
  36                                      IAggregateVisitor<TLabel, BlockWithLabels<TLabel>, bool> {
  37                 private readonly SubroutineBuilder<TLabel> builder;
  38                 private BlockWithLabels<TLabel> current_block;
  39
  40                 private BlockBuilder (SubroutineBuilder<TLabel> builder)
  41                 {
  42                         this.builder = builder;
  43                 }
  44
  45                 private SubroutineBase<TLabel> CurrentSubroutine
  46                 {
  47                         get { return this.builder.CurrentSubroutine; }
  48                 }
  49
  50                 #region IAggregateVisitor<Label,BlockWithLabels<Label>,bool> Members
  51                 public override bool Branch (TLabel pc, TLabel target, bool leavesExceptionBlock, BlockWithLabels<TLabel> currentBlock)
  52                 {
  53                         currentBlock.AddLabel (pc);
  54                         CurrentSubroutine.AddSuccessor (currentBlock, EdgeTag.Branch, CurrentSubroutine.GetTargetBlock (target));
  55
  56                         return true;
  57                 }
  58
  59                 public override bool BranchCond (TLabel pc, TLabel target, BranchOperator bop, Dummy value1, Dummy value2, BlockWithLabels<TLabel> currentBlock)
  60                 {
  61                         return HandleConditionalBranch (pc, target, true, currentBlock);
  62                 }
  63
  64                 public override bool BranchFalse (TLabel pc, TLabel target, Dummy cond, BlockWithLabels<TLabel> currentBlock)
  65                 {
  66                         return HandleConditionalBranch (pc, target, false, currentBlock);
  67                 }
  68
  69                 public override bool BranchTrue (TLabel pc, TLabel target, Dummy cond, BlockWithLabels<TLabel> currentBlock)
  70                 {
  71                         return HandleConditionalBranch (pc, target, true, currentBlock);
  72                 }
  73
  74                 public override bool Throw (TLabel pc, Dummy exception, BlockWithLabels<TLabel> currentBlock)
  75                 {
  76                         currentBlock.AddLabel (pc);
  77                         return true;
  78                 }
  79
  80                 public override bool Rethrow (TLabel pc, BlockWithLabels<TLabel> currentBlock)
  81                 {
  82                         currentBlock.AddLabel (pc);
  83                         return true;
  84                 }
  85
  86                 public override bool EndFinally (TLabel pc, BlockWithLabels<TLabel> currentBlock)
  87                 {
  88                         currentBlock.AddLabel (pc);
  89                         CurrentSubroutine.AddSuccessor (currentBlock, EdgeTag.EndSubroutine, CurrentSubroutine.Exit);
  90                         return true;
  91                 }
  92
  93                 public override bool Return (TLabel pc, Dummy source, BlockWithLabels<TLabel> currentBlock)
  94                 {
  95                         currentBlock.AddLabel (pc);
  96                         CurrentSubroutine.AddSuccessor (currentBlock, EdgeTag.Return, CurrentSubroutine.Exit);
  97                         CurrentSubroutine.AddReturnBlock (currentBlock);
  98
  99                         return true;
 100                 }
 101
 102                 public override bool Nop (TLabel pc, BlockWithLabels<TLabel> currentBlock)
 103                 {
 104                         return false;
 105                 }
 106
 107                 public override bool LoadField (TLabel pc, Field field, Dummy dest, Dummy obj, BlockWithLabels<TLabel> data)
 108                 {
 109                         if (CurrentSubroutine.IsMethod) {
 110                                 var methodInfo = (IMethodInfo) CurrentSubroutine;
 111                                 Property property;
 112                                 if (this.builder.MetaDataProvider.IsPropertyGetter (methodInfo.Method, out property))
 113                                         this.builder.SubroutineFacade.AddReads (methodInfo.Method, field);
 114                         }
 115                         this.current_block.AddLabel (pc);
 116                         return false;
 117                 }
 118
 119                 public override bool StoreField (TLabel pc, Field field, Dummy obj, Dummy value, BlockWithLabels<TLabel> data)
 120                 {
 121                         if (CurrentSubroutine.IsMethod) {
 122                                 var methodInfo = (IMethodInfo) CurrentSubroutine;
 123                                 Property property;
 124                                 if (this.builder.MetaDataProvider.IsPropertySetter (methodInfo.Method, out property))
 125                                         this.builder.SubroutineFacade.AddReads (methodInfo.Method, field);
 126                         }
 127                         this.current_block.AddLabel (pc);
 128                         return false;
 129                 }
 130
 131                 public override bool EndOld (TLabel pc, TLabel matchingBegin, TypeNode type, Dummy dest, Dummy source, BlockWithLabels<TLabel> data)
 132                 {
 133                         this.current_block.AddLabel (pc);
 134                         CurrentSubroutine.AddSuccessor (this.current_block, EdgeTag.EndOld, CurrentSubroutine.Exit);
 135                         return false;
 136                 }
 137
 138                 public bool Aggregate (TLabel pc, TLabel aggregateStart, bool canBeTargetOfBranch, BlockWithLabels<TLabel> data)
 139                 {
 140                         TraceAggregateSequentally (aggregateStart);
 141                         return false;
 142                 }
 143                 #endregion
 144
 145                 public static BlockWithLabels<TLabel> BuildBlocks (TLabel entry, SubroutineBuilder<TLabel> subroutineBuilder)
 146                 {
 147                         var blockBuilder = new BlockBuilder<TLabel> (subroutineBuilder);
 148                         blockBuilder.TraceAggregateSequentally (entry);
 149                         if (blockBuilder.current_block == null)
 150                                 return null;
 151
 152                         SubroutineBase<TLabel> subroutine = blockBuilder.CurrentSubroutine;
 153
 154                         subroutine.AddSuccessor (blockBuilder.current_block, EdgeTag.FallThroughReturn, subroutine.Exit);
 155                         subroutine.AddReturnBlock (blockBuilder.current_block);
 156
 157                         return blockBuilder.current_block;
 158                 }
 159
 160                 private void TraceAggregateSequentally (TLabel currentLabel)
 161                 {
 162                         do {
 163                                 if (this.builder.IsBlockStart (currentLabel))
 164                                         this.current_block = this.builder.RecordInformationForNewBlock (currentLabel, this.current_block);
 165                                 if (this.builder.CodeProvider.Decode<BlockBuilder<TLabel>, BlockWithLabels<TLabel>, bool> (currentLabel, this, this.current_block))
 166                                         this.current_block = null;
 167                         } while (this.builder.CodeProvider.Next (currentLabel, out currentLabel));
 168                 }
 169
 170                 public override bool DefaultVisit (TLabel pc, BlockWithLabels<TLabel> currentBlock)
 171                 {
 172                         currentBlock.AddLabel (pc);
 173                         return false;
 174                 }
 175
 176                 private bool HandleConditionalBranch (TLabel pc, TLabel target, bool isTrueBranch, BlockWithLabels<TLabel> currentBlock)
 177                 {
 178                         currentBlock.AddLabel (pc);
 179                         EdgeTag trueTag = isTrueBranch ? EdgeTag.True : EdgeTag.False;
 180                         EdgeTag falseTag = isTrueBranch ? EdgeTag.False : EdgeTag.True;
 181
 182                         AssumeBlock<TLabel> trueBlock = CurrentSubroutine.NewAssumeBlock (pc, trueTag);
 183                         this.builder.RecordInformationSameAsOtherBlock (trueBlock, this.current_block);
 184                         CurrentSubroutine.AddSuccessor (currentBlock, trueTag, trueBlock);
 185                         CurrentSubroutine.AddSuccessor (trueBlock, EdgeTag.FallThrough, CurrentSubroutine.GetTargetBlock (target));
 186
 187                         AssumeBlock<TLabel> falseBlock = CurrentSubroutine.NewAssumeBlock (pc, falseTag);
 188                         this.builder.RecordInformationSameAsOtherBlock (falseBlock, this.current_block);
 189                         CurrentSubroutine.AddSuccessor (currentBlock, falseTag, falseBlock);
 190                         this.current_block = falseBlock;
 191
 192                         return false;
 193                 }
 194         }
 195 }