From b787b333fb56b7fe670ba78335d84f48304303d0 Mon Sep 17 00:00:00 2001
From: Jochen Seyfried <j.seyfriedj@gmail.com>
Date: Fri, 28 Jun 2024 20:29:58 +0200
Subject: [PATCH] Fixed usage of fields

---
 .../Expression/LocalVarIdentifier.java        | 80 +++++++++++--------
 1 file changed, 47 insertions(+), 33 deletions(-)

diff --git a/src/main/java/abstractSyntaxTree/Expression/LocalVarIdentifier.java b/src/main/java/abstractSyntaxTree/Expression/LocalVarIdentifier.java
index a4ccd73..772eef6 100644
--- a/src/main/java/abstractSyntaxTree/Expression/LocalVarIdentifier.java
+++ b/src/main/java/abstractSyntaxTree/Expression/LocalVarIdentifier.java
@@ -46,46 +46,60 @@ public class LocalVarIdentifier extends AbstractType implements IExpression{
 
     @Override
     public void codeGen(MethodVisitor mv, LinkedHashMap<String, String> localVars, HashMap<String, HashMap<String, String>> typeContext, HashMap<String, HashMap<String, HashMap<String, ParameterList>>> methodContext) throws Exception {
-        // Check if the variable is in the list of local variables
-
         String type = null;
-        if (localVars.containsKey(identifier)){
+
+        // if it's a local variable
+        if (localVars.containsKey(identifier)) {
             type = localVars.get(identifier);
-        } else {
-            // check if instvar
-            type = typeContext.get(thisClass).get(identifier);
-        }
-        if (type == null){
-            throw new Exception("Variable " + identifier + " not declared");
-        }
-
-        //TODO: What if field
-
-        // Find the index of the variable
-        int index = -1;
-        int counter = 0;
-        for (String key : localVars.keySet()){
-            if (key.equals(identifier)){
-                index = counter+1; // +1 because the first local variable is at index 1, 0 is used for "this"
-                break;
+            // Find the index of the variable
+            int index = -1;
+            int counter = 0;
+            for (String key : localVars.keySet()) {
+                if (key.equals(identifier)) {
+                    index = counter + 1; // +1 because the first local variable is at index 1, 0 is used for "this"
+                    break;
+                }
+                counter++;
             }
-            counter++;
-        }
 
-        if (index == -1){
+            if (index == -1) {
+                throw new Exception("Variable " + identifier + " not found");
+            }
+
+            // Load the variable onto the stack
+            switch (type) {
+                case "int", "boolean", "char":
+                    mv.visitVarInsn(Opcodes.ILOAD, index);
+                    break;
+                case "void":
+                    break;
+                default:
+                    mv.visitVarInsn(Opcodes.ALOAD, index);
+                    break;
+            }
+            // If it's a field
+        } else if (typeContext.get(thisClass).get(identifier) != null){
+            type = typeContext.get(thisClass).get(identifier);
+
+            // Load "this" onto the stack
+            mv.visitVarInsn(Opcodes.ALOAD, 0);
+            // Get the field from "this"
+            mv.visitFieldInsn(Opcodes.GETFIELD, thisClass, identifier, getFieldDescriptor(type));
+        } else
             throw new Exception("Variable " + identifier + " not found");
-        }
+    }
 
-        // Load the variable onto the stack
-        switch (type){
-            case "int", "boolean", "char":
-                mv.visitVarInsn(Opcodes.ILOAD, index);
-                break;
-            case "void":
-                break;
+    //TODO move this to a helper class and remove the doubled code in MethodDecl and in other places
+    private String getFieldDescriptor(String type) {
+        switch (type) {
+            case "int":
+                return "I";
+            case "boolean":
+                return "Z";
+            case "char":
+                return "C";
             default:
-                mv.visitVarInsn(Opcodes.ALOAD, index);
-                break;
+                return "L" + type + ";";
         }
     }