Fix loop over a range literal up to MAX_VALUE

#KT-492 In Progress For Byte, Char and Short explicit casting from Int is removed -- loop parameter is already stored in an Int anyway. For Int and Long comparison "i < end" at the beginning of the loop is replaced to "i != end" at the end of the loop + a special check for an empty loop
2013-06-17 21:47:41 +04:00
parent f1a6d27d35
commit 33d6347876
10 changed files with 561 additions and 31 deletions
@@ -509,6 +509,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
        Label continueLabel = new Label();

        generator.beforeLoop();
+        generator.checkEmptyLoop(loopExit);

        v.mark(loopEntry);
        generator.conditionAndJump(loopExit);
@@ -518,7 +519,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
        generator.body();
        blockStackElements.pop();
        v.mark(continueLabel);
-        generator.afterBody();
+        generator.afterBody(loopExit);

        v.goTo(loopEntry);

@@ -583,6 +584,8 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
            }
        }

+        public abstract void checkEmptyLoop(@NotNull Label loopExit);
+
        public abstract void conditionAndJump(@NotNull Label loopExit);

        public void beforeBody() {
@@ -628,7 +631,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem

        protected abstract void assignToLoopParameter();

-        protected abstract void increment();
+        protected abstract void increment(@NotNull Label loopExit);

        public void body() {
            gen(forExpression.getBody(), Type.VOID_TYPE);
@@ -649,8 +652,8 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
            return varIndex;
        }

-        public void afterBody() {
-            increment();
+        public void afterBody(@NotNull Label loopExit) {
+            increment(loopExit);

            v.mark(bodyEnd);
        }
@@ -712,6 +715,10 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
            v.store(iteratorVarIndex, asmTypeForIterator);
        }

+        @Override
+        public void checkEmptyLoop(@NotNull Label loopExit) {
+        }
+
        @Override
        public void conditionAndJump(@NotNull Label loopExit) {
            // tmp<iterator>.hasNext()
@@ -741,7 +748,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
        }

        @Override
-        protected void increment() {
+        protected void increment(@NotNull Label loopExit) {
        }
    }

@@ -777,6 +784,10 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
            v.store(indexVar, Type.INT_TYPE);
        }

+        @Override
+        public void checkEmptyLoop(@NotNull Label loopExit) {
+        }
+
        @Override
        public void conditionAndJump(@NotNull Label loopExit) {
            v.load(indexVar, Type.INT_TYPE);
@@ -803,7 +814,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
        }

        @Override
-        protected void increment() {
+        protected void increment(@NotNull Label loopExit) {
            v.iinc(indexVar, 1);
        }
    }
@@ -811,8 +822,13 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
    private abstract class AbstractForInRangeLoopGenerator extends AbstractForLoopGenerator {
        protected int endVar;

+        // True iff instead of comparing loopParameterVar < endVar at the beginning of an iteration we check whether
+        // loopParameterVar == endVar at the end of the iteration (and also if there should be any iterations at all, before the loop)
+        private final boolean checkEqualityInsteadOfComparison;
+
        private AbstractForInRangeLoopGenerator(@NotNull JetForExpression forExpression) {
            super(forExpression);
+            checkEqualityInsteadOfComparison = asmElementType.getSort() == Type.INT || asmElementType.getSort() == Type.LONG;
        }

        @Override
@@ -823,27 +839,41 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
            storeRangeStartAndEnd();
        }

+        @Override
+        public void checkEmptyLoop(@NotNull Label loopExit) {
+            if (!checkEqualityInsteadOfComparison) return;
+
+            v.load(loopParameterVar, asmElementType);
+            v.load(endVar, asmElementType);
+            if (asmElementType.getSort() == Type.INT) {
+                v.ificmpgt(loopExit);
+            }
+            else if (asmElementType.getSort() == Type.LONG) {
+                v.lcmp();
+                v.ifgt(loopExit);
+            }
+            else {
+                throw new IllegalStateException("Unexpected type for empty loop checking: " + asmElementType);
+            }
+        }
+
        protected abstract void storeRangeStartAndEnd();

        @Override
        public void conditionAndJump(@NotNull Label loopExit) {
+            if (checkEqualityInsteadOfComparison) return;
+
            v.load(loopParameterVar, asmElementType);
            v.load(endVar, asmElementType);

            int sort = asmElementType.getSort();
            switch (sort) {
-                case Type.INT:
                case Type.CHAR:
                case Type.BYTE:
                case Type.SHORT:
                    v.ificmpgt(loopExit);
                    break;

-                case Type.LONG:
-                    v.lcmp();
-                    v.ifgt(loopExit);
-                    break;
-
                case Type.FLOAT:
                case Type.DOUBLE:
                    v.cmpg(asmElementType);
@@ -859,8 +889,27 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
        protected void assignToLoopParameter() {
        }

+        private void checkPostCondition(@NotNull Label loopExit) {
+            v.load(loopParameterVar, asmElementType);
+            v.load(endVar, asmElementType);
+            if (asmElementType.getSort() == Type.INT) {
+                v.ificmpeq(loopExit);
+            }
+            else if (asmElementType.getSort() == Type.LONG) {
+                v.lcmp();
+                v.ifeq(loopExit);
+            }
+            else {
+                throw new IllegalStateException("Unexpected type for equality: " + asmElementType);
+            }
+        }
+
        @Override
-        protected void increment() {
+        protected void increment(@NotNull Label loopExit) {
+            if (checkEqualityInsteadOfComparison) {
+                checkPostCondition(loopExit);
+            }
+
            int sort = asmElementType.getSort();
            switch (sort) {
                case Type.INT:
@@ -868,11 +917,6 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
                case Type.BYTE:
                case Type.SHORT:
                    v.iinc(loopParameterVar, 1);
-                    if (sort != Type.INT) {
-                        v.load(loopParameterVar, Type.INT_TYPE);
-                        StackValue.coerce(Type.INT_TYPE, asmElementType, v);
-                        v.store(loopParameterVar, asmElementType);
-                    }
                    break;

                case Type.LONG:
@@ -973,6 +1017,10 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
            generateRangeOrProgressionProperty(asmLoopRangeType, "getIncrement", incrementType, incrementVar);
        }

+        @Override
+        public void checkEmptyLoop(@NotNull Label loopExit) {
+        }
+
        @Override
        public void conditionAndJump(@NotNull Label loopExit) {
            v.load(loopParameterVar, asmElementType);
@@ -1059,7 +1107,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
        }

        @Override
-        protected void increment() {
+        protected void increment(@NotNull Label loopExit) {

            v.load(loopParameterVar, asmElementType);
            v.load(incrementVar, asmElementType);