public static bool TryOptimizeShortCircuit(Node head)
{
if ((head is BasicBlock) &&
(head as BasicBlock).BranchBasicBlock != null &&
(head as BasicBlock).FallThroughBasicBlock != null) {
head.Parent.MergeChilds<SimpleBranch>(head);
return true;
}
Branch top = head as Branch;
if (top == null) return false;
Branch left = head.FloatUpToNeighbours(top.TrueSuccessor) as Branch;
Branch right = head.FloatUpToNeighbours(top.FalseSuccessor) as Branch;
// A & B
if (left != null &&
left.Predecessors.Count == 1 &&
left.FalseSuccessor == top.FalseSuccessor) {
ShortCircuitBranch scBranch = top.Parent.MergeChilds<ShortCircuitBranch>(top, left);
scBranch.Operator = ShortCircuitOperator.LeftAndRight;
return true;
}
// ~A | B
if (left != null &&
left.Predecessors.Count == 1 &&
left.TrueSuccessor == top.FalseSuccessor) {
ShortCircuitBranch scBranch = top.Parent.MergeChilds<ShortCircuitBranch>(top, left);
scBranch.Operator = ShortCircuitOperator.NotLeftOrRight;
return true;
}
// A | B
if (right != null &&
right.Predecessors.Count == 1 &&
right.TrueSuccessor == top.TrueSuccessor) {
ShortCircuitBranch scBranch = top.Parent.MergeChilds<ShortCircuitBranch>(top, right);
scBranch.Operator = ShortCircuitOperator.LeftOrRight;
return true;
}
// ~A & B
if (right != null &&
right.Predecessors.Count == 1 &&
right.FalseSuccessor == top.TrueSuccessor) {
ShortCircuitBranch scBranch = top.Parent.MergeChilds<ShortCircuitBranch>(top, right);
scBranch.Operator = ShortCircuitOperator.NotLeftAndRight;
return true;
}
return false;
}
IEnumerable<Ast.INode> TransformNode(Node node)
{
if (Options.NodeComments) {
yield return MakeComment("// " + node.Description);
}
yield return new Ast.LabelStatement(node.Label);
if (node is BasicBlock) {
foreach(ILNode expr in ((BasicBlock)node).Body) {
if (expr is ILLabel) {
yield return new Ast.LabelStatement(((ILLabel)expr).Name);
} else {
Statement stmt = TransformExpressionToStatement((ILExpression)expr);
if (stmt != null) {
yield return stmt;
}
}
}
foreach(Ast.INode inode in TransformNodes(node.Childs)) {
yield return inode;
}
Node fallThroughNode = ((BasicBlock)node).FallThroughBasicBlock;
// If there is default branch and it is not the following node
if (fallThroughNode != null) {
yield return new Ast.GotoStatement(fallThroughNode.Label);
}
} else if (node is AcyclicGraph) {
foreach(Ast.INode inode in TransformNodes(node.Childs)) {
yield return inode;
}
} else if (node is Loop) {
Ast.BlockStatement blockStatement = new Ast.BlockStatement();
blockStatement.Children.AddRange(TransformNodes(node.Childs));
yield return new Ast.ForStatement(
null,
null,
null,
blockStatement
);
} else if (node is Block) {
foreach(Ast.INode inode in TransformNodes(node.Childs)) {
yield return inode;
}
} else if (node is Branch) {
yield return new Ast.LabelStatement(((Branch)node).FirstBasicBlock.Label);
Ast.BlockStatement trueBlock = new Ast.BlockStatement();
trueBlock.Children.Add(new Ast.GotoStatement(((Branch)node).TrueSuccessor.Label));
Ast.BlockStatement falseBlock = new Ast.BlockStatement();
falseBlock.Children.Add(new Ast.GotoStatement(((Branch)node).FalseSuccessor.Label));
Ast.IfElseStatement ifElseStmt = new Ast.IfElseStatement(
MakeBranchCondition((Branch)node),
trueBlock,
falseBlock
);
trueBlock.Parent = ifElseStmt;
falseBlock.Parent = ifElseStmt;
yield return ifElseStmt;
} else if (node is ConditionalNode) {
ConditionalNode conditionalNode = (ConditionalNode)node;
yield return new Ast.LabelStatement(conditionalNode.Condition.FirstBasicBlock.Label);
Ast.BlockStatement trueBlock = new Ast.BlockStatement();
// The block entry code
trueBlock.Children.Add(new Ast.GotoStatement(conditionalNode.Condition.TrueSuccessor.Label));
// Sugested content
trueBlock.Children.AddRange(TransformNode(conditionalNode.TrueBody));
Ast.BlockStatement falseBlock = new Ast.BlockStatement();
// The block entry code
falseBlock.Children.Add(new Ast.GotoStatement(conditionalNode.Condition.FalseSuccessor.Label));
// Sugested content
falseBlock.Children.AddRange(TransformNode(conditionalNode.FalseBody));
Ast.IfElseStatement ifElseStmt = new Ast.IfElseStatement(
// Method bodies are swapped
new Ast.UnaryOperatorExpression(
new Ast.ParenthesizedExpression(
MakeBranchCondition(conditionalNode.Condition)
),
UnaryOperatorType.Not
),
falseBlock,
trueBlock
);
trueBlock.Parent = ifElseStmt;
falseBlock.Parent = ifElseStmt;
yield return ifElseStmt;
} else if (node is TryCatchNode) {
TryCatchNode tryCachNode = ((TryCatchNode)node);
Ast.BlockStatement tryBlock = new Ast.BlockStatement();
tryBlock.Children.AddRange(TransformNode(tryCachNode.Childs[0]));
Ast.BlockStatement finallyBlock = null;
if (tryCachNode.Childs[1].Childs.Count > 0) {
finallyBlock = new Ast.BlockStatement();
finallyBlock.Children.AddRange(TransformNode(tryCachNode.Childs[1]));
}
List<Ast.CatchClause> ccs = new List<CatchClause>();
for (int i = 0; i < tryCachNode.Types.Count; i++) {
Ast.BlockStatement catchBlock = new Ast.BlockStatement();
catchBlock.Children.AddRange(TransformNode(tryCachNode.Childs[i + 2]));
Ast.CatchClause cc = new Ast.CatchClause(
new Ast.TypeReference(tryCachNode.Types[i].FullName),
"exception",
catchBlock
);
ccs.Add(cc);
}
Ast.TryCatchStatement tryCachStmt = new Ast.TryCatchStatement(tryBlock, ccs, finallyBlock);
yield return tryCachStmt;
} else {
throw new Exception("Bad node type");
}
if (Options.NodeComments) {
yield return MakeComment("");
}
}