From 024cddfa95cdeed073dd4eebcd8edd96b1d93955 Mon Sep 17 00:00:00 2001
From: Apoorva Ranade <apoorvaranade02@gmail.com>
Date: Sun, 25 Apr 2021 22:15:20 +0530
Subject: [PATCH] Analyze if expr and stmt

---
 src/main/java/chocopy/pa3/CodeGenImpl.java | 54 ++++++++++++++--------
 1 file changed, 36 insertions(+), 18 deletions(-)

diff --git a/src/main/java/chocopy/pa3/CodeGenImpl.java b/src/main/java/chocopy/pa3/CodeGenImpl.java
index 9a264a7..7e3a7ef 100644
--- a/src/main/java/chocopy/pa3/CodeGenImpl.java
+++ b/src/main/java/chocopy/pa3/CodeGenImpl.java
@@ -68,7 +68,7 @@ public class CodeGenImpl extends CodeGenBase {
     private final Label errorDiv = new Label("error.Div");
     /** Index out of bounds. */
     private final Label errorOob = new Label("error.OOB");
-
+    
     /**
      * Emits the top level of the program.
      *
@@ -158,6 +158,11 @@ public class CodeGenImpl extends CodeGenBase {
         /** The descriptor for the current function, or null at the top level. */
         private final FuncInfo funcInfo;
 
+        /** Label of code that exits from block. */
+        protected Label elseBlock;
+        // Variable to store offset from frame pointer to identify next 
+        // empty space on stack frame to store variable
+        private final int offset = 12;
         /**
          * An analyzer for the function described by FUNCINFO0, which is null for the
          * top level.
@@ -236,38 +241,52 @@ public class CodeGenImpl extends CodeGenBase {
             return null;
         }
         
-        @Override
-        public Void analyze(BinaryExpr node) {
-            return null;
-         }
          @Override
          public Void analyze(ExprStmt node) {
             node.expr.dispatch(this);
             return null;
          }
-     
          @Override
-         public Void analyze(ForStmt node) {
-                 // control flow
-             return defaultAction(node);
+         public Void analyze(IfExpr node) {
+            node.condition.dispatch(this);
+            Label ln = generateLocalLabel();
+            node.thenExpr.dispatch(this);
+            backend.emitJ(ln, "Jump to end of if expression");
+            backend.emitLocalLabel(elseBlock, "Else part of if expression");
+            node.elseExpr.dispatch(this);
+            backend.emitLocalLabel(ln, "End of if expression");
+            return null;
          }
          @Override
-         public Void analyze(Identifier node) {
-                 // statement
-             return defaultAction(node);
+         public Void analyze(IfStmt node) {
+            node.condition.dispatch(this);
+            Label ln = generateLocalLabel();
+            for(Stmt s:node.thenBody)
+                s.dispatch(this);
+            backend.emitJ(ln, "Jump to end of if statement");
+            backend.emitLocalLabel(elseBlock, "Else part of if statement");
+            for(Stmt s:node.elseBody)
+                s.dispatch(this);
+            backend.emitLocalLabel(ln, "End of if statement");
+            return null;
          }
-     
          @Override
-         public Void analyze(IfExpr node) {
+        public Void analyze(BinaryExpr node) {
+            elseBlock = generateLocalLabel();
+            return null;
+         }
+        
+         @Override
+         public Void analyze(ForStmt node) {
                  // control flow
              return defaultAction(node);
          }
-     
          @Override
-         public Void analyze(IfStmt node) {
-                // control flow
+         public Void analyze(Identifier node) {
+                 // statement
              return defaultAction(node);
          }
+         
      
          @Override
          public Void analyze(IndexExpr node) {
@@ -276,7 +295,6 @@ public class CodeGenImpl extends CodeGenBase {
          }
      
          
-     
          @Override
          public Void analyze(ListExpr node) {
                  // statement