augmented assignments for arrays; replace the hack of "value before receiver" with a lesser hack of dupReceiver()

idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java

@@ -781,7 +781,7 @@ public class ExpressionCodegen extends JetVisitor {
     private void generateAssignmentExpression(JetBinaryExpression expression) {
         StackValue stackValue = generateIntermediateValue(expression.getLeft());
         genToJVMStack(expression.getRight());
-        stackValue.store(v, false);
+        stackValue.store(v);
     }
 
     private void generateAugmentedAssignment(JetBinaryExpression expression) {
@@ -789,11 +789,11 @@ public class ExpressionCodegen extends JetVisitor {
         final JetExpression lhs = expression.getLeft();
         Type asmType = expressionType(lhs);
         StackValue value = generateIntermediateValue(lhs);
+        value.dupReceiver(v);
         value.put(asmType, v);
         genToJVMStack(expression.getRight());
         v.visitInsn(asmType.getOpcode(opcodeForMethod(op.getName())));
-        value = generateIntermediateValue(lhs);
-        value.store(v, true);
+        value.store(v);
     }
 
     private void generateConcatenation(JetBinaryExpression expression) {
@@ -896,6 +896,7 @@ public class ExpressionCodegen extends JetVisitor {
             }
         }
         StackValue value = generateIntermediateValue(operand);
+        value.dupReceiver(v);
         value.put(asmType, v);
         if (asmType == Type.LONG_TYPE) {
             v.aconst(Long.valueOf(increment));
@@ -910,8 +911,7 @@ public class ExpressionCodegen extends JetVisitor {
             v.aconst(increment);
         }
         v.add(asmType);
-        value = generateIntermediateValue(operand);
-        value.store(v, true);
+        value.store(v);
         return value;
     }
 

idea/src/org/jetbrains/jet/codegen/StackValue.java

@@ -19,10 +19,13 @@ public abstract class StackValue {
 
     public abstract void put(Type type, InstructionAdapter v);
 
-    public void store(InstructionAdapter v, boolean valueBeforeReceiver) {
+    public void store(InstructionAdapter v) {
         throw new UnsupportedOperationException("cannot store to value " + this);
     }
 
+    public void dupReceiver(InstructionAdapter v) {
+    }
+
     public void condJump(Label label, boolean jumpIfFalse, InstructionAdapter v) {
         if (this.type == Type.BOOLEAN_TYPE) {
             put(Type.BOOLEAN_TYPE, v);
@@ -160,7 +163,7 @@ public abstract class StackValue {
         }
 
         @Override
-        public void store(InstructionAdapter v, boolean valueBeforeReceiver) {
+        public void store(InstructionAdapter v) {
             v.store(index, this.type);
         }
     }
@@ -328,9 +331,14 @@ public abstract class StackValue {
         }
 
         @Override
-        public void store(InstructionAdapter v, boolean valueBeforeReceiver) {
+        public void store(InstructionAdapter v) {
             v.astore(type);   // assumes array and index are on the stack
         }
+
+        @Override
+        public void dupReceiver(InstructionAdapter v) {
+            v.dup2();   // array and index
+        }
     }
 
     private static class Field extends StackValue {
@@ -351,11 +359,12 @@ public abstract class StackValue {
         }
 
         @Override
-        public void store(InstructionAdapter v, boolean valueBeforeReceiver) {
-            // HACK should find some way to avoid this swap
-            if (valueBeforeReceiver && !isStatic) {
-                v.swap();
-            }
+        public void dupReceiver(InstructionAdapter v) {
+            if (!isStatic) v.dup();
+        }
+
+        @Override
+        public void store(InstructionAdapter v) {
             v.visitFieldInsn(isStatic ? Opcodes.PUTSTATIC : Opcodes.PUTFIELD, owner, name, this.type.getDescriptor());
         }
     }

idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java

@@ -338,10 +338,18 @@ public class NamespaceGenTest extends CodegenTestCase {
 
     public void testArrayWrite() throws Exception {
         loadText("fun foo(c: Array<String>) { c[0] = \"jet\"; }");
-        System.out.println(generateToText());
         final Method main = generateFunction();
         String[] array = new String[] { null };
         main.invoke(null, new Object[] { array });
         assertEquals("jet", array[0]);
     }
+
+    public void testArrayAugAssign() throws Exception {
+        loadText("fun foo(c: Array<Int>) { c[0] *= 2 }");
+        System.out.println(generateToText());
+        final Method main = generateFunction();
+        int[] data = new int[] { 5 };
+        main.invoke(null, new Object[] { data });
+        assertEquals(10, data[0]);
+    }
 }