finish `list[1]` = "fuckyou", passing more

src/main/java/chocopy/pa3/CodeGenImpl.java

@@ -398,6 +398,7 @@ public class CodeGenImpl extends CodeGenBase {
             RiscVBackend.Register tmpReg = /*regMgr.borrowOneTmp()*/ T6;
             RiscVBackend.Register tmpReg2 = /*regMgr.borrowOneTmp()*/ T5;
             betterBackend.emitPop(tmpReg, "ASSIGN: Get the value to assign: Pop the expr result from stack");
+
             SymbolType symbolType = null;
             for(Expr expr : node.targets) {
                 if (expr instanceof MemberExpr) {
@@ -433,9 +434,20 @@ public class CodeGenImpl extends CodeGenBase {
                     } else if (foundMethod) {
                         //TODO: Implement
                     }
-                } else {
+                }
+                else if(expr instanceof IndexExpr) {
+                    IndexExpr indexExpr = (IndexExpr) expr;
+                    indexExpr.list.dispatch(this);
+                    indexExpr.index.dispatch(this);
+                    RiscVBackend.Register indexReg = A6, listReg = tmpReg2, lenReg = A7, elementReg = tmpReg;
+                    betterBackend.emitPop(indexReg, "Assign list element: get index");
+                    betterBackend.emitPop(listReg, "Assign list element: get list");
+
+                    emitSetListElement(listReg, indexReg, lenReg, elementReg);
+                }
+                else {
                     SymbolInfo symbolInfo = sym.get(((Identifier) expr).name);
-                    Label label = null;
+                    /* Recolic: no need to deal with int/bool anymore. they're only wrapped before calling print.
                     if(symbolType == null) {
                         // first run:
                         if (symbolInfo instanceof GlobalVarInfo) {
@@ -449,9 +461,10 @@ public class CodeGenImpl extends CodeGenBase {
                             // first run:
                         /* All int and bool variable is not wrapped.
                         backend.emitLW(tmpReg, tmpReg, 3 * backend.getWordSize(), "ASSIGN: Load the value of INT or BOOL");
-                        */
+                        *-/
                         }
                     }
+                    */
 
                     // do assign
                     if (symbolInfo instanceof GlobalVarInfo) {
@@ -932,6 +945,7 @@ public class CodeGenImpl extends CodeGenBase {
 
         private void emitGetElementByIndex(RiscVBackend.Register listReg, RiscVBackend.Register indexReg, RiscVBackend.Register lenReg, SymbolType listType) {
             //! Note: All registers in argument will be modified! listType should be listType or STR_TYPE
+            //! Note: You need to set listReg, indexReg. lenReg is just a temp reg, no need to set it.
             //! @returns: listReg
             //! listReg is resultReg. Return list element ptr, or new string ptr.
             backend.emitLW(lenReg, listReg, 3*backend.getWordSize(), "IndexExpr: Get List/str length");
@@ -969,10 +983,39 @@ public class CodeGenImpl extends CodeGenBase {
 
                 backend.emitMV(listReg, A0, "IndexExpr: move result string to resultReg");
             }
+        }
+
+         private void emitSetListElement(RiscVBackend.Register listReg, RiscVBackend.Register indexReg, RiscVBackend.Register lenReg, RiscVBackend.Register elementReg) {
+            /* DO NOT edit this function. it's copy-pasted from emitGetElement. keep them consist. */
+            //! Note: All registers in argument will be modified! listType should be listType or STR_TYPE
+            //! Note: You need to set listReg, indexReg, elementReg. lenReg is just a temp reg, no need to set it.
+            backend.emitLW(lenReg, listReg, 3*backend.getWordSize(), "IndexExpr: Get List/str length");
+            backend.emitADDI(listReg, listReg, 4*backend.getWordSize(), "IndexExpr: listPtr = list.data");
+
+            String labelPrefix = getLabelPrefix();
+            Label skipTranslateNegIndex = new Label(labelPrefix + ".fuckNegIndexEnd");
+
+            // Get real index.
+            // Recolic: they don't like "abc"[-1], they want to crash it . Remove the feature and make them happy.
+            // backend.emitBGEZ(indexReg, skipTranslateNegIndex, "IndexExpr: Skip neg index op");
+            // backend.emitADD(indexReg, indexReg, lenReg, "IndexExpr: Add length to negative index.");
+            backend.emitBLTZ(indexReg, errorOob, "IndexExpr: Exception: negative index still negative after adding length. FUCK IT!!!");
 
+            backend.emitLocalLabel(skipTranslateNegIndex, "IndexExpr: DO REAL ACCESS");
+            // Do real access!
+            backend.emitBGE(indexReg, lenReg, errorOob, "IndexExpr: Exception: index larger than length. FUCK IT.");
+            if(true) {
+                assert backend.getWordSize() == 4;
+                backend.emitSLLI(indexReg, indexReg, 2, "IndexExpr: for list, element size = 4 char, so: indexReg *= 4");
+            }
+            backend.emitADD(listReg, listReg, indexReg, "IndexExpr: listPtr += index");
 
+            // do real set!
+            backend.emitSW(elementReg, listReg, 0, "IndexExpr Assign: Do real assign.");
         }
 
+
+
         @Override
         public Void analyze(IndexExpr node) {
             node.list.dispatch(this);