Added Bytecode generation Logic for datatypes and binary expressions

Source/abstractSyntaxTree/Datatype/BoolDatatype.java

@@ -2,6 +2,7 @@ package abstractSyntaxTree.Datatype;
 
 import TypeCheck.AbstractType;
 import TypeCheck.TypeCheckResult;
+import org.objectweb.asm.*;
 
 public class BoolDatatype extends AbstractType implements IDatatype{
     boolean value;
@@ -14,4 +15,13 @@ public class BoolDatatype extends AbstractType implements IDatatype{
         setTypeCheckResult(result);
         return result;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        if(value) {
+            mv.visitInsn(Opcodes.ICONST_1); // Pushes the int 1 on the stack (true)
+        } else {
+            mv.visitInsn(Opcodes.ICONST_0); // 0 for false
+        }
+    }
 }

Source/abstractSyntaxTree/Datatype/CharDatatype.java

@@ -2,6 +2,7 @@ package abstractSyntaxTree.Datatype;
 
 import TypeCheck.AbstractType;
 import TypeCheck.TypeCheckResult;
+import org.objectweb.asm.MethodVisitor;
 
 public class CharDatatype extends AbstractType implements IDatatype{
     char value;
@@ -14,4 +15,13 @@ public class CharDatatype extends AbstractType implements IDatatype{
         setTypeCheckResult(result);
         return result;
     }
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+
+        // Possible use of BIPUSH and SIPUSH if the value is small enough
+        //This saves space in the bytecode which is not very relevant at this point, but could be implemented anyway
+
+        mv.visitLdcInsn((int)value);
+    }
 }

Source/abstractSyntaxTree/Datatype/IDatatype.java

@@ -1,10 +1,15 @@
 package abstractSyntaxTree.Datatype;
 
 import TypeCheck.TypeCheckResult;
+import org.objectweb.asm.MethodVisitor;
 
 public interface IDatatype {
     // typeCheck method
     TypeCheckResult typeCheck() throws Exception;
 
     // visit method for code generation
+
+    void CodeGen(MethodVisitor mv) throws Exception;
 }
+
+//TODO: Check if we need to differentiate between primitive types and reference types --> for example in "=="

Source/abstractSyntaxTree/Datatype/IntDatatype.java

@@ -2,6 +2,8 @@ package abstractSyntaxTree.Datatype;
 
 import TypeCheck.AbstractType;
 import TypeCheck.TypeCheckResult;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
 
 public class IntDatatype extends AbstractType implements IDatatype{
     int value;
@@ -14,4 +16,19 @@ public class IntDatatype extends AbstractType implements IDatatype{
         setTypeCheckResult(result);
         return result;
     }
+
+    // visit method for code generation
+
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        
+        //Example of using BIPUSH and SIPUSH for optimizing bytecode size
+        if (value >= Byte.MIN_VALUE && value <= Byte.MAX_VALUE)
+            mv.visitIntInsn(Opcodes.BIPUSH, value);
+        else if (value >= Short.MIN_VALUE && value <= Short.MAX_VALUE)
+            mv.visitIntInsn(Opcodes.SIPUSH, value);
+        else
+            mv.visitLdcInsn(value);
+    }
 }

Source/abstractSyntaxTree/Datatype/RefType.java

@@ -4,6 +4,8 @@ import TypeCheck.AbstractType;
 import TypeCheck.TypeCheckResult;
 import abstractSyntaxTree.Class.FieldDecl;
 import abstractSyntaxTree.Class.MethodDecl;
+import jdk.jshell.spi.ExecutionControl;
+import org.objectweb.asm.MethodVisitor;
 
 import java.util.List;
 
@@ -31,4 +33,13 @@ public class RefType extends AbstractType implements IDatatype {
         setTypeCheckResult(result);
         return result;
     }
+
+    // Method for code generation which iterates over all the field declarations
+    // and method declarations and calls their CodeGen methods
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        throw new ExecutionControl.NotImplementedException("CodeGen not implemented for RefType");
+    }
+
+
 }

Source/abstractSyntaxTree/Expression/BinaryExpression.java

@@ -3,7 +3,9 @@ package abstractSyntaxTree.Expression;
 import TypeCheck.TypeCheckResult;
 import TypeCheck.TypeCheckHelper;
 import TypeCheck.AbstractType;
+import org.objectweb.asm.*;
 
+import java.beans.Expression;
 import java.util.Objects;
 
 public class BinaryExpression extends AbstractType implements IExpression{
@@ -54,4 +56,115 @@ public class BinaryExpression extends AbstractType implements IExpression{
         setTypeCheckResult(result);
         return result;
     }
+
+
+    @Override
+    public void CodeGen(MethodVisitor mv) throws Exception {
+        // Label for the jump instruction
+        Label operationFalse = new Label();   //Operation is false
+        Label operationTrue = new Label();    //Operation is true
+        // Labels are placed at the end of this method
+        Label expressionEnd = new Label();     //End of the whole expression
+
+        // Bytecode for the binary operation
+        switch (operator) {
+            case "&&":
+                left.CodeGen(mv);
+                mv.visitJumpInsn(Opcodes.IFEQ, operationFalse); // IFEQ --> "if equals to zero" (false) --> if left exp is false
+
+                right.CodeGen(mv);
+                mv.visitJumpInsn(Opcodes.IFEQ, operationFalse); // If right exp is false, jump to the end of the whole expression
+
+                mv.visitJumpInsn(Opcodes.GOTO, operationTrue); // If it reaches this point, the right exp is true
+                break;
+
+            case "||":
+                left.CodeGen(mv);
+                mv.visitJumpInsn(Opcodes.IFNE, operationTrue); // IFNE --> "if not equals to zero" (true) --> if left exp is true
+
+                right.CodeGen(mv);
+                mv.visitJumpInsn(Opcodes.IFNE, operationTrue);
+                break;
+
+           case "==":
+               // Keep in mind that only primitive types are allowed in this case (at this time)
+
+               left.CodeGen(mv);
+               right.CodeGen(mv);
+
+                mv.visitJumpInsn(Opcodes.IF_ICMPEQ, operationTrue); // If the two values are equal, jump to the end of the expression
+                break;
+
+            case "<":
+                left.CodeGen(mv);
+                right.CodeGen(mv);
+
+                mv.visitJumpInsn(Opcodes.IF_ICMPLT, operationTrue); // Checks only on less than, not equal
+                break;
+
+            case ">":
+                left.CodeGen(mv);
+                right.CodeGen(mv);
+
+                mv.visitJumpInsn(Opcodes.IF_ICMPGT, operationTrue); // Checks only on greater than, not equal
+                break;
+
+            case "<=":
+                left.CodeGen(mv);
+                right.CodeGen(mv);
+
+                mv.visitJumpInsn(Opcodes.IF_ICMPLE, operationTrue); // Checks on less than OR equal
+                break;
+
+            case ">=":
+                left.CodeGen(mv);
+                right.CodeGen(mv);
+
+                mv.visitJumpInsn(Opcodes.IF_ICMPGE, operationTrue); // Checks on greater than OR equal
+                break;
+
+            case "!=":
+                left.CodeGen(mv);
+                right.CodeGen(mv);
+
+                mv.visitJumpInsn(Opcodes.IF_ICMPNE, operationTrue); // Checks on not equal
+                break;
+
+            case "+":
+                left.CodeGen(mv);
+                right.CodeGen(mv);
+                mv.visitInsn(Opcodes.IADD);
+                break;
+
+            case "-":
+                left.CodeGen(mv);
+                right.CodeGen(mv);
+                mv.visitInsn(Opcodes.ISUB);
+                break;
+
+            case "*":
+                left.CodeGen(mv);
+                right.CodeGen(mv);
+                mv.visitInsn(Opcodes.IMUL);
+                break;
+
+            case "/":
+                left.CodeGen(mv);
+                right.CodeGen(mv);
+                mv.visitInsn(Opcodes.IDIV);
+                break;
+
+            default:
+                throw new Exception("Unknown operator: " + operator);
+        }
+
+        mv.visitLabel(operationFalse);
+        mv.visitInsn(Opcodes.ICONST_0); // Push false on the stack
+        mv.visitJumpInsn(Opcodes.GOTO, expressionEnd); // Jump to the end of the expression (skip the true push)
+
+        mv.visitLabel(operationTrue);
+        mv.visitInsn(Opcodes.ICONST_1); // Push true on the stack
+
+        mv.visitLabel(expressionEnd);
+    }
 }

Source/abstractSyntaxTree/Expression/IExpression.java

@@ -1,10 +1,12 @@
 package abstractSyntaxTree.Expression;
 
 import TypeCheck.TypeCheckResult;
+import org.objectweb.asm.MethodVisitor;
 
 public interface IExpression {
     // typeCheck method
     TypeCheckResult typeCheck() throws Exception;
 
     // visit method for code generation
+    void CodeGen(MethodVisitor mv) throws Exception;
 }