def visitWhileStmt(self, ctx: DecafParser.WhileStmtContext):
self.enterScope('whileblock' + str(self.anonCounter))
self.anonCounter += 1
whileNode = ICNode('while')
code = []
conditionlabel = self.gen_label()
elselabel = self.gen_label()
expr = self.visit(ctx.expression())
condition = expr.lt
self.free_temporal(condition)
code.append(conditionlabel)
code += expr.code
code.append('IFNOT ' + condition + ' goto ' + elselabel)
whileblock = self.visit(ctx.block())
code += whileblock.code
code.append('goto ' + conditionlabel)
code.append(elselabel)
whileNode.code = code
self.exitScope()
return whileNode
def visitBlock(self, ctx: DecafParser.BlockContext):
blockNode = ICNode('none')
code = []
for statement in ctx.statement():
v = self.visitStatement(statement)
code += v.code if v else []
blockNode.code = code
return blockNode
def visitNegationExpr(self, ctx: DecafParser.NegativeExprContext):
t = self.visit(ctx.expression)
new_temp = self.get_temporal()
code = []
negated = ICNode('!', right=t)
code += t.code
code.append(new_temp + ' = NOT ' + t.lt)
self.free_temporal(t.lt)
negated.code = code
negated.lt = new_temp
return negated
def visitReturnStmt(self, ctx: DecafParser.ReturnStmtContext):
expr = self.visit(ctx.expression())
returnNode = ICNode('return')
code = []
code += expr.code
code.append(self.gen_code(RETURN_REGISTER, expr.lt, '', ''))
self.free_temporal(expr.lt)
code.append('BX LR')
returnNode.code = code
return returnNode
def visitLocation(self, ctx: DecafParser.LocationExprContext, struct=None):
var_name = ctx.name.text
scope = self.scopes.peek()
var, scopeName = scope.lookup(var_name)
tokenEXPR = ctx.expr
tokenLOC = ctx.loc
locNode = ICNode('location')
if not tokenEXPR and not tokenLOC:
locNode.lt = self.get_location(scopeName, var.offset)
return locNode
#We have a list
elif tokenEXPR and not tokenLOC:
size = scope.typeTable.getSize(var.stype)
# EZ index is a number
if (index := ctx.expr.getText()).isnumeric():
locNode.lt = self.get_location(scopeName,
var.offset + size * int(index))
return locNode
# Index is an expression
code = []
expr = self.visit(tokenEXPR)
# 2 new temporals, to compute the new offset
new_temp = self.get_temporal()
new_temp2 = self.get_temporal()
# if expression is a location, we get a string, if not we get an ICNode
location = expr
if not isinstance(expr, str):
code += expr.code
location = expr.lt
self.free_temporal(expr.lt)
code.append(self.gen_code(new_temp, location, '*', size))
code.append(self.gen_code(new_temp2, new_temp, '+', var.offset))
self.free_temporal(new_temp)
self.free_temporal(new_temp2)
locNode.code = code
locNode.lt = self.get_location(scopeName, new_temp2)
return locNode
def visitAssignStmt(self, ctx: DecafParser.AssignStmtContext):
destination = self.visit(ctx.left)
right = self.visit(ctx.right)
loc = destination
assignNode = ICNode('=', left=destination, right=right)
code = []
code += right.code
if not isinstance(destination, str):
code += destination.code
loc = destination.lt
code.append(self.gen_code(loc, right.lt, '', ''))
self.free_temporal(right.lt)
assignNode.code = code
return assignNode
def visitMethodCall(self, ctx: DecafParser.MethodCallExprContext):
methodCallNode = ICNode('call')
code = []
method_label = str(ctx.ID())
scope = self.scopes.peek()
method = scope.typeExists(method_label, 'method')
for argument in ctx.arg():
argNode = self.visitArg(argument)
code += argNode.code
code.append('PushParam ' + argNode.lt)
self.free_temporal(argNode.lt)
code.append('LCall ' + method_label)
code.append('PopParams ' + str(method.size))
methodCallNode.lt = RETURN_REGISTER
methodCallNode.code = code
return methodCallNode
def visitIfStmt(self, ctx: DecafParser.IfStmtContext):
self.enterScope('ifblock' + str(self.anonCounter))
self.anonCounter += 1
ifNode = ICNode('if')
code = []
elselabel = self.gen_label()
expr = self.visit(ctx.expression())
condition = expr.lt
self.free_temporal(condition)
code += expr.code
code.append('IFNOT ' + condition + ' goto ' + elselabel)
ifblock = self.visit(ctx.ifblock)
code += ifblock.code
if ctx.elseblock:
endlabel = self.gen_label()
code.append('goto ' + endlabel)
code.append(elselabel)
elseblock = self.visit(ctx.elseblock)
code += elseblock.code
code.append(endlabel)
else:
code.append(elselabel)
ifNode.code = code
self.exitScope()
return ifNode
def visitRelationOp(self, ctx: DecafParser.RelationOpContext):
op = ctx.op.getText()
left_node = self.visit(ctx.left)
right_node = self.visit(ctx.right)
self.free_temporal(left_node.lt)
self.free_temporal(right_node.lt)
rel = ICNode(op, right_node, left_node)
code = []
code += left_node.code
code += right_node.code
new_temp = self.get_temporal()
code.append(self.gen_code(new_temp, left_node.lt, op, right_node.lt))
rel.code = code
rel.lt = new_temp
return rel
def visitArithOp(self, ctx: DecafParser.ArithOpContext):
op = ctx.op.getText()
left_node = self.visit(ctx.left)
right_node = self.visit(ctx.right)
self.free_temporal(left_node.lt)
self.free_temporal(right_node.lt)
arith = ICNode(op, right_node, left_node)
code = []
code += left_node.code
code += right_node.code
new_temp = self.get_temporal()
code.append(self.gen_code(new_temp, left_node.lt, op, right_node.lt))
arith.code = code
arith.lt = new_temp
return arith
def visitEqualityOp(self, ctx: DecafParser.EqualityOpContext):
op = ctx.op.getText()
left_node = self.visit(ctx.left)
right_node = self.visit(ctx.right)
self.free_temporal(left_node.lt)
self.free_temporal(right_node.lt)
eq = ICNode(op, right_node, left_node)
code = []
code += left_node.code
code += right_node.code
new_temp = self.get_temporal()
code.append(self.gen_code(new_temp, left_node.lt, op, right_node.lt))
eq.code = code
eq.lt = new_temp
return eq