Code Generator

package compiler ;

import java.io.* ;
import java.util.* ;
import COM.sootNsmoke.jvm.* ;
import COM.sootNsmoke.instructions.* ;

public class CodeGenerator extends Instructions implements RuntimeConstants, ASTVisitor {

   JavaClass jcf ;
   String progname ;

   int count ;             // global count for unique labels.

   /*
   * Number of local variables in current procedure.
   * Also includes parameter values of the procedure.
   */
   int proc_localvars ;

   boolean procdecs ;        // Are we in procedure declaration ?
   boolean procparamdecs ; // Are we in procedure params declaration ?

   Hashtable localvars ;   // This is a hack. Ideally this information should
                       // be part of the symbol table.
   String procsig ;        // Signature of the current proc.

   Hashtable proctable ;   // Another hack. holds methods and their signature.
                         // Should have used symbol table.

   public CodeGenerator() {
       jcf = null ;
       progname = null ;
       count = -1 ;
       proc_localvars = -1 ;        // -1 for meaningless.
       procdecs = false ;
       procparamdecs = false ;
       localvars = null ;
       procsig = null ;
       proctable = new Hashtable() ;
   }

   public void generate(AST ast){
       ast.visit(this, null) ;
   }

      public Object visitCompilationUnit(CompilationUnit p, Object arg) {
       if(p.cd != null){
           p.cd.visit(this,null);
       }
       return null ;
   }

   public Object visitClassDeclaration(ClassDeclaration p, Object arg) {
       Sequence main_codeseq ;
       jcf = new JavaClass(p.classname.terminal, "java/lang/Object");
       progname = p.classname.terminal ;

       main_codeseq = nop();
       if(p.classbody != null){
           main_codeseq = (Sequence) p.classbody.visit(this, null) ;
       }

       // Add the default constructor to the class
       // Assumption : 0 will be the number for this object always
       Sequence const_sequence = aload(0) ;

       // This is the default one argument constructor. So it always calls
       // java.lang.Object's
       // init (<init> is the name of the constructor within bytecode format) and returns
       // Ideally this should be done withing visitFunctionDec aftet checking the method
       // name is equal to class name then generating the code for the method, which will
       // then be the constructor with name <init>

       const_sequence = const_sequence.append(invokespecial("java/lang/Object", "<init>", "()V"));
       const_sequence = const_sequence.append(return_()) ;


       System.out.println(const_sequence.toString());
       jcf.addMethod("<init>", "()V", ACC_PUBLIC, const_sequence.max_stack(),1, const_sequence.toByteArray(jcf), null, null, null) ;

       // ie do the following
       // Move all the new changes above classbody.visit()

       //main_codeseq = main_codeseq.append(return_()) ;
       //System.out.println(main_codeseq.toString());
       //byte[] code = main_codeseq.toByteArray(jcf);
       //jcf.addMethod("main", "([Ljava/lang/String;)V",(ACC_PUBLIC | ACC_STATIC), main_codeseq.max_stack(),1, code, null, null, null) ;

       try{
           jcf.write(new FileOutputStream(p.classname.terminal+".class"));
       }catch (java.io.IOException ioe){
           System.out.println(ioe) ;
       }
       return null ;
   }

   public Object visitClassBody(ClassBody p,Object arg) {
       Sequence seq = (Sequence) p.ds.visit(this,null);
       return seq ;
   }

   public Object visitVariableDeclarations(VariableDeclarations p,Object arg) {
                System.out.println("Code Generation: In Visit Variable Declarations");

       if (!procdecs && (p.type.primitivetype.toString().equals("[ int ]") || p.type.primitivetype.toString().equals("[ boolean ]"))){
           if(p.staticvariable!=null){
               jcf.addField(p.variablename.terminal, (ACC_PUBLIC | ACC_STATIC), 0) ;
           }else{
               jcf.addField(p.variablename.terminal, (ACC_PUBLIC ), 0) ;
           }
       }

       else if (procdecs) {
           localvars.put(p.variablename.terminal, new Integer(proc_localvars)) ;

           if (procparamdecs && (p.type.primitivetype.toString().equals("[ int ]") || p.type.primitivetype.toString().equals("[ boolean ]"))){
               System.out.println("Adding int to signature ") ;
               procsig = procsig+"I" ;
           }
           else
               { System.out.println("not Adding int to signature "+p.type.primitivetype+procparamdecs) ; }
           proc_localvars = proc_localvars + 1 ;
       }
       // TBD , should be changed for HW6.
       return null ;
   }

   public Object visitFunctionDeclarations(FunctionDeclarations p,Object arg) {
       Sequence procseq = null ;

       procseq = nop() ;

       proc_localvars = 0 ;
       procdecs = true ;
       localvars = new Hashtable() ;
       procsig = "(" ;

       if (p.parameterlist != null)   {
           procparamdecs = true ;
           p.parameterlist.visit(this, null) ;
           procparamdecs = false ;

           procsig = procsig+")" ;

           // TBD : handle image.
           if(p.type.ptype == true){
               if (p.type.primitivetype.terminal.equals("int") || p.type.primitivetype.terminal.equals("boolean")) {
                   //procseq = procseq.append(ireturn()) ;   // TBD : remove this ?
                   procsig = procsig+"I" ;
               }else if (p.type.primitivetype.terminal.equals("void")){
                   //procseq = procseq.append(return_()) ;
                   procsig = procsig+"V" ;
               }
           }
           proctable.put(p.functionname.terminal, procsig) ;
       }else{
           procsig = procsig+")" ;

           // TBD : handle image.
           if(p.type.ptype == true){
               if (p.type.primitivetype.terminal.equals("int") || p.type.primitivetype.terminal.equals("boolean")) {
                   //procseq = procseq.append(ireturn()) ;   // TBD : remove this ?
                   procsig = procsig+"I" ;
               }else if (p.type.primitivetype.terminal.equals("void")){
                   //procseq = procseq.append(return_()) ;
                   procsig = procsig+"V" ;
               }
           }
       }

       if(p.block != null){
           if (p.block.dec != null) {
               p.block.dec.visit(this, null) ;
           }
           if (p.block.cmd != null) {
               procseq = (Sequence) p.block.cmd.visit(this, null) ;
           }
       }

       // TBD : chk this jcf
       byte[] procCode = procseq.toByteArray(jcf);
       System.out.println(" Fnction : "+p.functionname.terminal+" start ************") ;
       System.out.println("No of local vars + params :"+proc_localvars);
       System.out.println("Local Variables :"+localvars);
       System.out.println("Stack size :"+procseq.max_stack());
       System.out.println("Signature :"+procsig);
       System.out.println(procseq.toString());
       System.out.println(" Function : "+p.functionname.terminal+"end ************") ;

            if(p.staticfunction!=null){

       // I really don't know why this proc_localvars+1 is required. But with this it works.

       jcf.addMethod(p.functionname.terminal, procsig, (ACC_PUBLIC | ACC_STATIC),
                   procseq.max_stack(), proc_localvars+1, procCode,
                       null, null, null) ;
       }else{
       // I really don't know why this proc_localvars+1 is required. But with this it works.
       jcf.addMethod(p.functionname.terminal, procsig, (ACC_PUBLIC),
                   procseq.max_stack(), proc_localvars+1, procCode,
                       null, null, null) ;

       }
       proc_localvars = -1 ;
       procdecs = false ;
       localvars = null ;
       procsig = null ;
       return procseq ;
   }

   public Object visitBlock(Block p,Object arg) {
       return null ;
   }

   public Object visitMethodCallExpression(MethodCallExpression p,Object arg) {
       System.out.println("Code Generation : In Visit MethodCall Expression") ;
       Sequence codeseq = null ;
       String signature = (String) proctable.get(p.tan.name.name) ;
       if (p.exp   != null){
           codeseq = (Sequence) p.exp.visit(this, null) ;
           System.out.println("Code Generation : In Visit Function Expression" + p.tan.name.name + signature) ;
           codeseq = codeseq.append(invokestatic(progname, p.tan.name.name, signature));
       }else{
           codeseq = invokestatic(progname, p.tan.name.name, signature) ;
       }
       return codeseq ;
   }

   public Object visitMethodCallCommand(MethodCallCommand p,Object arg) {
       System.out.println("Code Generation : In Visit MethodCall Command ") ;
       Sequence codeseq = null ;
       String signature = (String) proctable.get(p.tan.name.name) ;
       if (p.exp != null){
           codeseq = (Sequence) p.exp.visit(this, null) ;
           codeseq = codeseq.append(invokestatic(progname, p.tan.name.name, signature));
       }else{
           codeseq = invokestatic(progname, p.tan.name.name, signature) ;
       }
       return codeseq ;
   }

   public Object visitAssignmentCommand(AssignmentCommand p,Object arg) {
       Sequence codeseq = null ;
       System.out.println("Code Generation : In Visit Assignment Command ") ;
       codeseq = (Sequence) p.exp.visit(this, null) ;

       if (procdecs){
           Integer location = (Integer) localvars.get(p.tan.name.name) ;

           // THIS WILL RAISE A CLASS CAST EXCEPTION IF YOU TRY SAY j = 10 anywhere.
           // p.exp.visit will always return a sequence object. You cannot convert that
           // to string. Get the type information from the symbol table as you know the
           // variable name.
           // presently I am commenting this piece of code and assuming only ints are
           // there so that I can test the rest of the code.

           // String temp = (String)p.exp.visit(this,null);
           if ( location != null) {
               // THIS IS MY TEMP FIX
                   codeseq = codeseq.append(istore(location.intValue())) ;

               // the varexpr refers to local variable.
/*               if ( temp.equals("int") || temp.equals("bool") ){
                   codeseq = codeseq.append(istore(location.intValue())) ;
               }
               if ( p.exp.type.equals("image") ){
                   codeseq = codeseq.append(astore(location.intValue())) ;
               }*/
               return codeseq ;
           }
           // the varexpr refers to global variable.
       }

// SAME AS ABOVE ASSUMING ONLY INTS
       codeseq = codeseq.append(putstatic(progname, p.tan.name.name, "I")) ;

// IMPORTANT : Infact this is sufficient as you don't have image or any other objects for now, but only ints and
// bools.
       // String temp = (String)p.exp.visit(this,null);
       // System.out.println("Code Generation: In Visit Assignment command "+temp) ;
/*       if ( temp.equals("int") || temp.equals("bool") ){
           codeseq = codeseq.append(putstatic(progname, p.tan.name.name, "I")) ;
       }

       else if ( p.exp.type.equals("image") ){
           codeseq = codeseq.append(putstatic(progname, p.id.t,
                    "Ljava/awt/image/BufferedImage;")) ;
       }*/
       return codeseq ;
   }

   public Object visitUnaryOpExpression(UnaryOpExpression p,Object arg){
       System.out.println("Code Generation : In Visit UnaryOp Expression") ;
       Sequence codeseq = null ;
       String id = null ;
       codeseq = (Sequence) p.exp.visit(this, null) ;

       if (p.op.terminal.equals("+")){
           codeseq = codeseq.append(nop()) ;
       }else if (p.op.terminal.equals("-")){
           codeseq = codeseq.append(ldc(-1)) ;
           codeseq = codeseq.append(imul()) ;
       }else if (p.op.terminal.equals("!")){//SOME CHANGE HERE. I USED SAME CODE FOR "~"
           id = getNewId() ;
           codeseq = codeseq.append(ifeq("zero"+id)) ;
           codeseq = codeseq.append(ldc(0)) ;
           codeseq = codeseq.append(goto_("done_una"+id)) ;
           codeseq = codeseq.append(label("zero"+id)) ;
           codeseq = codeseq.append(ldc(1)) ;
           codeseq = codeseq.append(label("done_una"+id)) ;
       }
       return codeseq ;
   }

   public Object visitBinaryOpExpression(BinaryOpExpression p,Object arg){
       System.out.println("Code Generation : In Visit BinaryOp Expression") ;

       Sequence codeseq = null ;
       Sequence tmpseq = null ;
       String id = null ;
       codeseq = (Sequence) p.expressionone.visit(this, null) ;
       tmpseq = (Sequence) p.expressiontwo.visit(this, null) ;
       codeseq = codeseq.append(tmpseq) ;

       if (p.operator.terminal.equals("+")){
           codeseq = codeseq.append(iadd()) ;
       }else if (p.operator.terminal.equals("-")){
           codeseq = codeseq.append(isub()) ;
       }else if (p.operator.terminal.equals("*")){
           codeseq = codeseq.append(imul()) ;
       }else if (p.operator.terminal.equals("/")){
           codeseq = codeseq.append(idiv()) ;
       }else if (p.operator.terminal.equals("&&")){
           codeseq = codeseq.append(iand()) ;
       }else if (p.operator.terminal.equals("||")){
           codeseq = codeseq.append(ior()) ;
       }else if (p.operator.terminal.equals("==")){
           id = getNewId() ;
           codeseq = codeseq.append(if_icmpeq("true"+id)) ;
           codeseq = codeseq.append(ldc(0)) ;
           codeseq = codeseq.append(goto_("done"+id)) ;
           codeseq = codeseq.append(label("true"+id)) ;
           codeseq = codeseq.append(ldc(1)) ;
           codeseq = codeseq.append(label("done"+id)) ;
       }else if (p.operator.terminal.equals("!=")){
           id = getNewId() ;
           codeseq = codeseq.append(if_icmpne("true"+id)) ;
           codeseq = codeseq.append(ldc(0)) ;
           codeseq = codeseq.append(goto_("done"+id)) ;
           codeseq = codeseq.append(label("true"+id)) ;
           codeseq = codeseq.append(ldc(1)) ;
           codeseq = codeseq.append(label("done"+id)) ;
       }else if (p.operator.terminal.equals("<=")){
           id = getNewId() ;
           codeseq = codeseq.append(if_icmple("true"+id)) ;
           codeseq = codeseq.append(ldc(0)) ;
           codeseq = codeseq.append(goto_("done"+id)) ;
           codeseq = codeseq.append(label("true"+id)) ;
           codeseq = codeseq.append(ldc(1)) ;
           codeseq = codeseq.append(label("done"+id)) ;
       }else if (p.operator.terminal.equals("<")){
           id = getNewId() ;
           codeseq = codeseq.append(if_icmplt("true"+id)) ;
           codeseq = codeseq.append(ldc(0)) ;
           codeseq = codeseq.append(goto_("done"+id)) ;
           codeseq = codeseq.append(label("true"+id)) ;
           codeseq = codeseq.append(ldc(1)) ;
           codeseq = codeseq.append(label("done"+id)) ;
       }else if (p.operator.terminal.equals(">")){
           id = getNewId() ;
           codeseq = codeseq.append(if_icmpgt("true"+id)) ;
           codeseq = codeseq.append(ldc(0)) ;
           codeseq = codeseq.append(goto_("done"+id)) ;
           codeseq = codeseq.append(label("true"+id)) ;
           codeseq = codeseq.append(ldc(1)) ;
           codeseq = codeseq.append(label("done"+id)) ;
       }else if (p.operator.terminal.equals(">=")){
           id = getNewId() ;
           codeseq = codeseq.append(if_icmpge("true"+id)) ;
           codeseq = codeseq.append(ldc(0)) ;
           codeseq = codeseq.append(goto_("done"+id)) ;
           codeseq = codeseq.append(label("true"+id)) ;
           codeseq = codeseq.append(ldc(1)) ;
           codeseq = codeseq.append(label("done"+id)) ;
       }
       return codeseq ;
   }

   public Object visitIntegerLiteralExpression(IntegerLiteralExpression p,Object arg) {
       System.out.println("Code Generation : In Visit Integer Literal Expression") ;
       Sequence codeseq = null ;

       System.out.println("Value:........"+p.value);
       int numlit = (new Integer(p.value)).intValue() ;
       System.out.println("Value:........"+numlit);
       //codeseq = codeseq.append(ldc(numlit)) ;
       codeseq = ldc(numlit) ;

       return codeseq ;
   }

   public Object visitBooleanLiteralExpression(BooleanLiteralExpression p,Object arg) {
       System.out.println("Code Generation : In Visit Boolean Literal Expression") ;
       Sequence codeseq = null ;
       String boollit = p.value;

       if (boollit.equals("true")){
           //codeseq = codeseq.append(ldc(1)) ;
           codeseq = ldc(1) ;
       }else
           if (boollit.equals("false")){
               //codeseq = codeseq.append(ldc(0)) ;
               codeseq = ldc(0) ;
           }
       return codeseq ;
   }

   public Object visitNullLiteralExpression(NullLiteralExpression p,Object arg) {
       return null ;
   }

   public Object visitSequenceExpression(SequenceExpression p,Object arg){
       System.out.println("Code Generation : In Visit Sequence Expression ") ;
       Sequence s1 = (Sequence) p.expressionone.visit(this, null) ;
       Sequence s2 = (Sequence) p.expressiontwo.visit(this, null) ;
               // SIVA CHANGED s2 can be null
       if ( s2 != null)
       {
       s1 = s1.append(s2) ;
       }
       return s1 ;
   }

   public Object visitSequenceCommand(SequenceCommand p,Object arg) {
       System.out.println("Code Generation : In Visit Sequence Command ") ;
       Sequence s1 = (Sequence) p.commandone.visit(this, arg) ;
       Sequence s2 = (Sequence) p.commandtwo.visit(this, arg) ;
       // SIVA CHANGED s2 can be null
       if ( s2 != null )
       {
       s1 = s1.append(s2) ;
       }
       return s1 ;
   }

   public Object visitSequenceDeclarations(SequenceDeclarations p,Object arg) {
       p.declarationsone.visit(this, null) ;
       p.declarationstwo.visit(this, null) ;
       return null ;
   }

   public Object visitIfElseCommand(IfElseCommand p, Object arg) {
       System.out.println("Code Generation : In Visit IfElse Command ") ;
       Sequence codeseq = null ;
       String id = getNewId() ;

       codeseq = (Sequence) p.expression.visit(this, null) ;
       codeseq = codeseq.append(ifeq("elsepart"+id)) ;

       if (p.command != null){
           codeseq = codeseq.append((Sequence) p.command.visit(this, null)) ;
       }

       codeseq = codeseq.append(goto_("endif"+id)) ;
       codeseq = codeseq.append(label("elsepart"+id)) ;

       if (p.ecommand != null){
               codeseq = codeseq.append((Sequence) p.ecommand.visit(this, null)) ;
       }

       codeseq = codeseq.append(label("endif"+id)) ;

       return codeseq ;
   }

   public Object visitWhileCommand(WhileCommand p, Object arg) {
       System.out.println("Code Generation : In Visit While Command ") ;
       Sequence codeseq = null ;
       String id = getNewId() ;

       codeseq = goto_("test"+id) ;
       codeseq = codeseq.append(label("body"+id)) ;
       if (p.command != null){
           codeseq = codeseq.append((Sequence) p.command.visit(this, null)) ;
       }

       codeseq = codeseq.append(label("test"+id)) ;
       codeseq = codeseq.append((Sequence) p.expression.visit(this, null)) ;
       codeseq = codeseq.append(ifne("body"+id)) ;

       return codeseq ;
   }


   public Object visitReturnCommand(ReturnCommand p, Object arg) {
       System.out.println("Code Generation : In Visit Return Command ") ;
       Sequence codeseq = null ;

       if (p.expression != null){
           codeseq = (Sequence) p.expression.visit(this, null) ;
           System.out.println("Type of expression : "+p.expression.type_of_expression) ;

           // It is "thisandname". something wrong with the assumption.
            // as we don't handle any other types than int and bool in codegen
           // I am removing the type check and always returning int.
           codeseq = codeseq.append(ireturn()) ;

/*
                        if (p.expression.type_of_expression.equals("int") || p.expression.type_of_expression.equals("boolean")){
               codeseq = codeseq.append(ireturn()) ;
           }else
               if (p.expression.type_of_expression.equals("void")){
                   // Should not be here
                   //codeseq = codeseq.append(return_()) ;
                   //codeseq = return_() ;
               } */
       }else{
           codeseq = return_() ;
       }
       return codeseq ;
   }

   public Object visitName(Name p,Object arg){

       // not of type objects. will work for local and instance variables.

       Sequence codeseq = null ;
       System.out.println("Code Generation : In Visit Name ") ;


       if (procdecs){
           Integer location = (Integer) localvars.get(p.name) ;
               codeseq = iload(location.intValue()) ;
               return codeseq ;
           // the varexpr refers to global variable.
       }

       codeseq = getstatic(progname, p.name, "I") ;

       return codeseq ;
   }

   public Object visitStatic(Static p,Object arg){
       return null ;
   }

   public Object visitModifier(Modifier p,Object arg){
       return null ;
   }

   public Object visitTerminal(Terminal p,Object arg){
       return null ;
   }

   public String getNewId(){
       count = count + 1 ;
       return (new Integer(count).toString()) ;
   }

   public Object visitSimplePWLExpression(SimplePWLExpression p,Object arg) { return null ;}

   public Object visitClassInstanceCreationExpression(ClassInstanceCreationExpression p,Object arg){ return null ;}

   public Object visitThisAndNameExpression(ThisAndNameExpression p,Object arg) {


   // Assuming "this" won't be there.
   return p.tan.visit(this, null) ;

   }

   public Object visitJustThis(JustThis p,Object arg) { return null ;}

   public Object visitThisAndName(ThisAndName p,Object arg){

   // Assuming "this" won't be there.
   // SIVA changed ...
   return p.name.visit(this, null) ;

   }

   public Object visitPrimitiveType(PrimitiveType p,Object arg){ return null ;}

   public Object visitReferenceType(ReferenceType p,Object arg){ return null ;}
}

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