public void Visit(Program program)
{
// the init op code sets up the call stack, to read command line arguments
var main = program.Definitions.Single(d => d.Name == "main");
tacs.Add(Tac.Init(main.Formals.Count));
// call main
tacs.Add(Tac.BeginCall(main.Name, main.Formals.Count, "t0"));
for (int i = 0; i < main.Formals.Count; i++)
{
tacs.Add(Tac.Param($"arg{i}"));
}
tacs.Add(Tac.Call("main", "t0"));
// call print
tacs.Add(Tac.BeginCall("print", 1, "t1"));
tacs.Add(Tac.Param("t0"));
tacs.Add(Tac.Call("print", "t1"));
tacs.Add(Tac.Halt());
// declare print function
tacs.Add(Tac.BeginFunc("print", 1));
tacs.Add(Tac.PrintVariable("arg0"));
tacs.Add(Tac.EndFunc("print"));
foreach (var definition in program.Definitions)
{
definition.Accept(this);
}
}
public void Visit(Definition definition)
{
// temps are local to the function so reset the counter for each func
// (makes it easy to work out where the temp is stored in the stack frame)
tempCounter = 0;
Ast.SymbolTable.CurrentFunction = definition.Name;
tacs.Add(Tac.BeginFunc(definition.Name, definition.Formals.Count));
definition.Body.Accept(this);
tacs.Add(Tac.EndFunc(definition.Name));
}
