public static bool TransformToIncDec(BlockNode block)
{
var children = block.GetChildren().ToList();
var changesmade = false;
for (var i = 0; i < children.Count; i++)
{
var node = children[i];
if (!(node is VariableAssignmentNode assignment))
{
continue;
}
BinaryOperatorNode expression = null;
if (assignment.Value is AdditionNode add)
{
expression = add;
}
if (assignment.Value is SubtractionNode sub)
{
expression = sub;
}
if (expression == null)
{
continue;
}
ExpressionNode left, right;
if (expression.Left is ShortValueNode)
{
left = expression.Left;
right = expression.Right;
}
else
{
right = expression.Left;
left = expression.Right;
}
if (left is ShortValueNode value && value.Value == 1 && right is VariableValueNode var && var.VariableName == assignment.VariableName)
{
children.RemoveAt(i);
block.RemoveChild(i);
if (expression is AdditionNode)
{
block.AddChild(new IncrementNode(assignment.VariableName));
}
else
{
block.AddChild(new DecrementNode(assignment.VariableName));
}
changesmade = true;
}
}
return(changesmade);
}
public void EmitAssembly_If_CreatesBlock_WithElse()
{
var ast = new ASTNode();
ast.AddChild(new VariableDeclarationNode("byte", "x"));
ast.AddChild(new VariableAssignmentNode("x", new ShortValueNode(1)));
var iftrueblock = new BlockNode();
iftrueblock.AddChild(new VariableAssignmentNode("x", new ShortValueNode(1)));
var iffalseblock = new BlockNode();
iffalseblock.AddChild(new VariableAssignmentNode("x", new ShortValueNode(2)));
ast.AddChild(new IfNode(new VariableValueNode("x"), iftrueblock, iffalseblock));
var asm = EmitAssembly(ast).ToArray();
ListEqual(new[] {
"LD C 1",
"XOR A",
"CP C",
"JP NZ generatedLabel1",
"LD C 1",
"JP generatedLabel2",
"generatedLabel1:",
"LD C 2",
"generatedLabel2:"
}, asm);
}
public override Node Visit(BlockNode block)
{
var blockNode = new BlockNode(block.Token, block.Depth);
foreach (var statement in block.ChildNodes)
{
blockNode.AddChild(statement.Accept(this));
}
return(blockNode);
}
public void PropagteConstants_If_ExtractsTrueBody()
{
var ast = new ASTNode();
ast.AddChild(new VariableDeclarationNode("byte", "x"));
ast.AddChild(new VariableAssignmentNode("x", new ShortValueNode(1)));
var block = new BlockNode();
block.AddChild(new VariableDeclarationNode("byte", "a"));
block.AddChild(new VariableAssignmentNode("a", new ShortValueNode(1)));
ast.AddChild(new IfNode(new VariableValueNode("x"), block));
var changesmade = PropagateConstants(ast);
Assert.IsTrue(changesmade);
var children = ast.GetChildren().ToList();
Assert.AreEqual(4, children.Count);
Assert.IsInstanceOfType(children[2], typeof(VariableDeclarationNode));
Assert.IsInstanceOfType(children[3], typeof(VariableAssignmentNode));
}
private void Block(BlockNode node)
{
RequiredToken(Tag.DL_LBRACE);
while (!TagIs(Tag.DL_RBRACE) && !TagIs(Tag.NULL))
{
if (Utils.IsTypeTag(next.Tag) || TagIs(Tag.KW_CONST))
{
DeclNode decl = new DeclNode();
node.AddChild(decl);
Decl(decl);
}
else
{
StmtNode stmt = new StmtNode();
node.AddChild(stmt);
Stmt(stmt);
}
}
RequiredToken(Tag.DL_RBRACE);
}
public override Node VisitBlock(BlockContext context)
{
_blockDepth++;
var blockNode = new BlockNode(context.Start, _blockDepth);
foreach (StatementContext x in context.statement())
{
blockNode.AddChild(Visit(x));
}
_blockDepth--;
return(blockNode);
}
public void PropagteConstants_If_ExtractsFalseBody()
{
var ast = new ASTNode();
ast.AddChild(new VariableDeclarationNode("byte", "x"));
ast.AddChild(new VariableAssignmentNode("x", new ShortValueNode(0)));
var iftrue = new BlockNode();
iftrue.AddChild(new VariableAssignmentNode("x", new ShortValueNode(1)));
var iffalse = new BlockNode();
iffalse.AddChild(new AdditionAssignmentNode("x", new ShortValueNode(2)));
ast.AddChild(new IfNode(new VariableValueNode("x"), iftrue, iffalse));
var changesmade = PropagateConstants(ast);
Assert.IsTrue(changesmade);
var children = ast.GetChildren().ToList();
Assert.AreEqual(3, children.Count);
Assert.IsInstanceOfType(children[2], typeof(AdditionAssignmentNode));
}