private List<Statement> RestoreControlFlow(List<ExpressionStatement> statements)
{
MarkTargetStatements(statements);
var blocks = BuildBasicBlocks(statements);
MarkJumpTargets(blocks);
RemoveRedundantBlocks(blocks);
int i = 0;
while(i < blocks.Count)
{
var block = blocks[i];
if (block.Predecessors.Count == 1 && block.Successors.Count == 2)
{
var thenBlock = block.Successors[0];
var nextBlock = block.Successors[1];
var condition = block.Condition;
if (condition != null &&
thenBlock.Predecessors.Count == 1 && thenBlock.Successors.Count == 1)
{
if (nextBlock.HasPredecessors(block, thenBlock))
{
block.RemoveSelf();
thenBlock.RemoveSelf();
var ifBlock = new ControlStatement(block.Predecessors[0], "if (" + condition + ")", thenBlock);
ifBlock.AddSuccessor(nextBlock);
blocks.Remove(block);
blocks.Remove(thenBlock);
blocks.Insert(i, ifBlock);
continue;
}
var jumpBlock = thenBlock.Successors[0];
var elseBlock = nextBlock;
if (jumpBlock.Successors.Count == 1)
{
nextBlock = jumpBlock.Successors[0];
if (nextBlock.HasPredecessors(jumpBlock, elseBlock))
{
block.RemoveSelf();
thenBlock.RemoveSelf();
jumpBlock.RemoveSelf();
elseBlock.RemoveSelf();
var ifStmt = new ControlStatement(block.Predecessors[0], "if (" + condition + ")",
thenBlock);
var elseStmt = new ControlStatement(ifStmt, "else", elseBlock);
elseStmt.AddSuccessor(nextBlock);
blocks.Remove(block);
blocks.Remove(thenBlock);
blocks.Remove(jumpBlock);
blocks.Remove(elseBlock);
blocks.Insert(i, ifStmt);
blocks.Insert(i+1, elseStmt);
continue;
}
}
}
}
if (block.Predecessors.Count == 2 && block.Successors.Count == 2)
{
var loopBody = block.Successors[0];
var loopEnd = block.Successors[1];
var condition = block.Condition;
if (condition != null &&
loopBody.Predecessors.Count == 1 && loopBody.Successors.Count == 1 &&
loopEnd.Predecessors.Count == 1)
{
var loopJump = loopBody.Successors[0];
if (loopJump.HasSuccessors(block))
{
block.RemoveSelf();
loopBody.RemoveSelf();
loopJump.RemoveSelf();
var whileBlock = new ControlStatement(block.Predecessors[0], "while (" + condition + ")", loopBody);
whileBlock.AddSuccessor(loopEnd);
blocks.Remove(block);
blocks.Remove(loopBody);
blocks.Remove(loopJump);
blocks.Insert(i, whileBlock);
}
}
}
i++;
}
if (IsControlFlowBuilt(blocks))
{
blocks.ForEach(block => block.ControlFlowDone = true);
}
return new List<Statement>(blocks);
}
private List <Statement> RestoreControlFlow(List <ExpressionStatement> statements)
{
MarkTargetStatements(statements);
var blocks = BuildBasicBlocks(statements);
MarkJumpTargets(blocks);
RemoveRedundantBlocks(blocks);
int i = 0;
while (i < blocks.Count)
{
var block = blocks[i];
if (block.Predecessors.Count == 1 && block.Successors.Count == 2)
{
var thenBlock = block.Successors[0];
var nextBlock = block.Successors[1];
var condition = block.Condition;
if (condition != null &&
thenBlock.Predecessors.Count == 1 && thenBlock.Successors.Count == 1)
{
if (nextBlock.HasPredecessors(block, thenBlock))
{
block.RemoveSelf();
thenBlock.RemoveSelf();
var ifBlock = new ControlStatement(block.Predecessors[0], "if (" + condition + ")", thenBlock);
ifBlock.AddSuccessor(nextBlock);
blocks.Remove(block);
blocks.Remove(thenBlock);
blocks.Insert(i, ifBlock);
continue;
}
var jumpBlock = thenBlock.Successors[0];
var elseBlock = nextBlock;
if (jumpBlock.Successors.Count == 1)
{
nextBlock = jumpBlock.Successors[0];
if (nextBlock.HasPredecessors(jumpBlock, elseBlock))
{
block.RemoveSelf();
thenBlock.RemoveSelf();
jumpBlock.RemoveSelf();
elseBlock.RemoveSelf();
var ifStmt = new ControlStatement(block.Predecessors[0], "if (" + condition + ")",
thenBlock);
var elseStmt = new ControlStatement(ifStmt, "else", elseBlock);
elseStmt.AddSuccessor(nextBlock);
blocks.Remove(block);
blocks.Remove(thenBlock);
blocks.Remove(jumpBlock);
blocks.Remove(elseBlock);
blocks.Insert(i, ifStmt);
blocks.Insert(i + 1, elseStmt);
continue;
}
}
}
}
if (block.Predecessors.Count == 2 && block.Successors.Count == 2)
{
var loopBody = block.Successors[0];
var loopEnd = block.Successors[1];
var condition = block.Condition;
if (condition != null &&
loopBody.Predecessors.Count == 1 && loopBody.Successors.Count == 1 &&
loopEnd.Predecessors.Count == 1)
{
var loopJump = loopBody.Successors[0];
if (loopJump.HasSuccessors(block))
{
block.RemoveSelf();
loopBody.RemoveSelf();
loopJump.RemoveSelf();
var whileBlock = new ControlStatement(block.Predecessors[0], "while (" + condition + ")", loopBody);
whileBlock.AddSuccessor(loopEnd);
blocks.Remove(block);
blocks.Remove(loopBody);
blocks.Remove(loopJump);
blocks.Insert(i, whileBlock);
}
}
}
i++;
}
if (IsControlFlowBuilt(blocks))
{
blocks.ForEach(block => block.ControlFlowDone = true);
}
return(new List <Statement>(blocks));
}
