Added Bytecodegeneration to the missing classes

Also included some TODOs in areas where parameters and some connections are missing

Source/abstractSyntaxTree/Expression/InstVarExpression.java

@@ -1,10 +1,32 @@
 package abstractSyntaxTree.Expression;
 
 import TypeCheck.TypeCheckResult;
+import abstractSyntaxTree.Datatype.RefType;
+import jdk.jshell.spi.ExecutionControl;
+import org.objectweb.asm.MethodVisitor;
 
 public class InstVarExpression implements IExpression{
+
+    //TODO: We have to decide upon more parameters and where they come from, for
+    // example here we need the index of the field, the class reference and the field name
+    private RefType classRef;
+    private String fieldName;
+
+/*    public InstVarExpression(RefType classRef, String fieldName){
+        this.classRef = classRef;
+        this.fieldName = fieldName;
+    }*/
     @Override
     public TypeCheckResult typeCheck() throws Exception {
         return null;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        throw new ExecutionControl.NotImplementedException("CodeGen not implemented for InstVarExpression");
+
+        //ALOAD the index of the var
+        //GETFIELD the field
+        //visitFieldInsn(Opcodes.GETFIELD, "class reference", "field name", type);
+    }
 }

Source/abstractSyntaxTree/Expression/UnaryExpression.java

@@ -4,6 +4,8 @@ import TypeCheck.AbstractType;
 import TypeCheck.TypeCheckHelper;
 import TypeCheck.TypeCheckResult;
 import abstractSyntaxTree.Datatype.IDatatype;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
 
 import java.util.Objects;
 
@@ -38,4 +40,26 @@ public class UnaryExpression extends AbstractType implements IExpression{
         setTypeCheckResult(result);
         return result;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+
+        operand.CodeGen(mv);
+
+        switch (operator) {
+            case "!":
+                //XOR with 1 to get the negation
+                mv.visitInsn(Opcodes.ICONST_1);
+                mv.visitInsn(Opcodes.IXOR);
+                break;
+            case "-":
+                mv.visitInsn(Opcodes.INEG);
+                break;
+            case "+":
+                break;
+
+            default: throw new Exception("Unknown operator :" + operator);
+        }
+
+    }
 }

Source/abstractSyntaxTree/Expression/VarRefExpression.java

@@ -1,10 +1,23 @@
 package abstractSyntaxTree.Expression;
 
 import TypeCheck.TypeCheckResult;
+import org.objectweb.asm.MethodVisitor;
+
+import java.util.Map;
 
 public class VarRefExpression implements IExpression{
+
+    //Parameters that are needed here
+    private String varName;
+    private Map<String, Integer> localVars;
+
     @Override
     public TypeCheckResult typeCheck() throws Exception {
         return null;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        throw new Exception("CodeGen not implemented for VarRefExpression");
+    }
 }

Source/abstractSyntaxTree/Modifier/IModifier.java

@@ -1,6 +1,10 @@
 package abstractSyntaxTree.Modifier;
 
 public interface IModifier {
+
+    //TODO: Maybe we can just use an enum for the Modifier
+    //      if there is no typeCheck and no CodeGen
+
     // not type or type check
 
     // visit method for code generation

Source/abstractSyntaxTree/Statement/BlockStatement.java

@@ -3,10 +3,13 @@ package abstractSyntaxTree.Statement;
 import TypeCheck.TypeCheckResult;
 import TypeCheck.AbstractType;
 import abstractSyntaxTree.Expression.IExpression;
+import org.objectweb.asm.MethodVisitor;
 
 import java.util.List;
 
 public class BlockStatement extends AbstractType implements IStatement{
+
+    //We will need a parameter which holds the symbol table
     List<IStatement> statements;
     public BlockStatement(List<IStatement> statements){
         this.statements = statements;
@@ -31,4 +34,11 @@ public class BlockStatement extends AbstractType implements IStatement{
         }
         return result;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        for (IStatement statement : statements) {
+            statement.CodeGen(mv); //TODO: I think we need to pass the symbol table here
+        }
+    }
 }

Source/abstractSyntaxTree/Statement/EmptyStatement.java

@@ -2,6 +2,7 @@ package abstractSyntaxTree.Statement;
 
 import TypeCheck.TypeCheckResult;
 import TypeCheck.AbstractType;
+import org.objectweb.asm.MethodVisitor;
 
 public class EmptyStatement  extends AbstractType implements IStatement{
     @Override
@@ -10,4 +11,9 @@ public class EmptyStatement  extends AbstractType implements IStatement{
         result.type = "void";
         return result;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        //An empty statement does not generate any code
+    }
 }

Source/abstractSyntaxTree/Statement/IStatement.java

@@ -1,10 +1,11 @@
 package abstractSyntaxTree.Statement;
 
 import TypeCheck.TypeCheckResult;
+import org.objectweb.asm.MethodVisitor;
 
 public interface IStatement {
 
     TypeCheckResult typeCheck() throws Exception;
 
-    // visit method for code generation
+    void CodeGen(MethodVisitor mv) throws Exception;
 }

Source/abstractSyntaxTree/Statement/IfElseStatement.java

@@ -3,6 +3,7 @@ package abstractSyntaxTree.Statement;
 import TypeCheck.TypeCheckResult;
 import TypeCheck.AbstractType;
 import abstractSyntaxTree.Expression.IExpression;
+import org.objectweb.asm.*;
 
 public class IfElseStatement extends AbstractType implements IStatement{
     IExpression condition;
@@ -35,4 +36,23 @@ public class IfElseStatement extends AbstractType implements IStatement{
         result.type = elseStatementType.type;
         return result;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+
+        Label conditionFalse = new Label();
+        Label statementEnd = new Label();
+
+        condition.CodeGen(mv);
+
+        mv.visitJumpInsn(Opcodes.IFEQ, conditionFalse); //Checks if the condition is false (0)
+        ifStatement.CodeGen(mv); //If the condition is true, execute the ifBlock
+        mv.visitJumpInsn(Opcodes.GOTO, statementEnd); //Jump to the end of the if-else statement
+
+        mv.visitLabel(conditionFalse);
+        elseStatement.CodeGen(mv); //If the condition is false, execute the elseBlock
+
+        mv.visitLabel(statementEnd); //End of the if-else statement
+
+    }
 }

Source/abstractSyntaxTree/Statement/IfStatement.java

@@ -3,9 +3,12 @@ package abstractSyntaxTree.Statement;
 import TypeCheck.TypeCheckResult;
 import TypeCheck.AbstractType;
 import abstractSyntaxTree.Expression.IExpression;
+import org.objectweb.asm.*;
 
 public class IfStatement extends AbstractType implements IStatement{
     IExpression condition;
+
+    //Do we need a block statement here?
     IStatement ifStatement;
 
     public IfStatement(IExpression condition, IStatement ifStatement) {
@@ -27,6 +30,18 @@ public class IfStatement extends AbstractType implements IStatement{
         return result;
     }
 
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+
+        Label conditionFalse = new Label();
+
+        condition.CodeGen(mv);
+
+        mv.visitJumpInsn(Opcodes.IFEQ, conditionFalse); //Checks if the condition is false (0)
+        ifStatement.CodeGen(mv);
+
+        mv.visitLabel(conditionFalse); // If the condition is false, the Statements in the ifBlock will not be executed
+    }
 }
 
 

Source/abstractSyntaxTree/Statement/ReturnStatement.java

@@ -3,6 +3,7 @@ package abstractSyntaxTree.Statement;
 import TypeCheck.TypeCheckResult;
 import TypeCheck.AbstractType;
 import abstractSyntaxTree.Expression.IExpression;
+import org.objectweb.asm.*;
 
 public class ReturnStatement extends AbstractType implements IStatement{
     IExpression expression;
@@ -24,4 +25,27 @@ public class ReturnStatement extends AbstractType implements IStatement{
 
         return result;
     }
+
+
+    //TODO: We do not differentiate between primitive types and reference types
+    //      This is a problem at "BinaryExpression" and here because we need to know the type to return
+    //      At this point in time we can either return reference types or have an error message
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+
+        if (expression != null) {
+            expression.CodeGen(mv);
+            //Get the Type of the expression
+            String type = expression.typeCheck().type;
+
+            if (type.equals("int") || type.equals("bool")) {
+                mv.visitInsn(Opcodes.IRETURN);
+            } else {
+                mv.visitInsn(Opcodes.ARETURN);
+
+            }
+        } else {
+            mv.visitInsn(Opcodes.RETURN);
+        }
+    }
 }

Source/abstractSyntaxTree/Statement/WhileStatement.java

@@ -3,14 +3,17 @@ package abstractSyntaxTree.Statement;
 import TypeCheck.TypeCheckResult;
 import TypeCheck.AbstractType;
 import abstractSyntaxTree.Expression.IExpression;
+import org.objectweb.asm.*;
 
-public class WhileStatement extends AbstractType implements IStatement{
+public class WhileStatement extends AbstractType implements IStatement {
     IExpression condition;
     IStatement statement;
+
     public WhileStatement(IExpression condition, IStatement statement) {
         this.condition = condition;
         this.statement = statement;
     }
+
     @Override
     public TypeCheckResult typeCheck() throws Exception {
         TypeCheckResult result = new TypeCheckResult();
@@ -26,4 +29,22 @@ public class WhileStatement extends AbstractType implements IStatement{
         result.type = statementType.type;
         return result;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        Label conditionFalse = new Label();
+        Label LoopStart = new Label();
+
+        mv.visitLabel(LoopStart);
+
+        condition.CodeGen(mv);
+        mv.visitJumpInsn(Opcodes.IFEQ, conditionFalse); // Checks if the condition is false (0)
+
+        statement.CodeGen(mv);
+        //TODO: If the block ends with a return statement, we might have to pop it from the stack
+        //      So the next iteration starts with a clean stack
+        mv.visitJumpInsn(Opcodes.GOTO, LoopStart); // Jump to the start of the while loop
+
+        mv.visitLabel(conditionFalse);
+    }
 }

Source/abstractSyntaxTree/StatementExpression/AssignStatementExpression.java

@@ -4,7 +4,10 @@ import TypeCheck.AbstractType;
 import TypeCheck.TypeCheckHelper;
 import TypeCheck.TypeCheckResult;
 import abstractSyntaxTree.Expression.IExpression;
+import abstractSyntaxTree.Expression.InstVarExpression;
+import abstractSyntaxTree.Expression.VarRefExpression;
 import abstractSyntaxTree.Statement.IStatement;
+import org.objectweb.asm.*;
 
 import java.util.Objects;
 
@@ -28,4 +31,20 @@ public class AssignStatementExpression extends AbstractType implements IExpressi
         setTypeCheckResult(result);
         return result;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        left.CodeGen(mv);
+        right.CodeGen(mv);
+
+        if (left instanceof VarRefExpression varRef) {
+            //TODO: Implement the handling of a variable reference --> I need a lis of local variables
+            //      for that to determine if the variable is a local or field variable
+        } else if (left instanceof InstVarExpression instVar) {
+            mv.visitInsn(Opcodes.DUP_X1);
+
+            // We now again need the owner (class reference), name (of the Field in the owner) and type of the field
+            //mv.visitFieldInsn(Opcodes.PUTFIELD, instVar.className, instVar.varName, instVar.type);
+        }
+    }
 }

Source/abstractSyntaxTree/StatementExpression/MethodCallStatementExpression.java

@@ -6,6 +6,8 @@ import abstractSyntaxTree.Class.MethodDecl;
 import abstractSyntaxTree.Datatype.RefType;
 import abstractSyntaxTree.Expression.IExpression;
 import abstractSyntaxTree.Statement.IStatement;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
 
 import java.util.List;
 
@@ -39,4 +41,22 @@ public class MethodCallStatementExpression extends AbstractType implements IExpr
 
         return result;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        //Generate Bytecode for the receiver
+        if(classThatHasTheMethodIfNotThis != null){
+            classThatHasTheMethodIfNotThis.CodeGen(mv);
+        } else {
+            mv.visitVarInsn(Opcodes.ALOAD, 0);
+        }
+
+        for (IExpression argument : arguments) {
+            argument.CodeGen(mv);
+        }
+
+        //We need the class reference and the return type of the method
+        //mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, thisClass.name, methodName, return type);
+
+    }
 }

Source/abstractSyntaxTree/StatementExpression/NewStatementExpression.java

@@ -4,10 +4,16 @@ import TypeCheck.AbstractType;
 import TypeCheck.TypeCheckResult;
 import abstractSyntaxTree.Expression.IExpression;
 import abstractSyntaxTree.Statement.IStatement;
+import org.objectweb.asm.MethodVisitor;
 
 public class NewStatementExpression extends AbstractType implements IExpression, IStatement {
     @Override
     public TypeCheckResult typeCheck() throws Exception {
         return null;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        throw new Exception("CodeGen not implemented for NewStatementExpression");
+    }
 }