fix KT-5645: 'continue' inside 'do...while' statement works as goto to the beginning of the loop (not checking loop condition)

#KT-5645 Fixed

compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java

@@ -424,10 +424,11 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
 
     @Override
     public StackValue visitDoWhileExpression(@NotNull JetDoWhileExpression expression, StackValue receiver) {
-        Label continueLabel = new Label();
-        v.mark(continueLabel);
+        Label beginLoopLabel = new Label();
+        v.mark(beginLoopLabel);
 
         Label breakLabel = new Label();
+        Label continueLabel = new Label();
 
         blockStackElements.push(new LoopBlockStackElement(breakLabel, continueLabel, targetLabel(expression)));
 
@@ -444,17 +445,17 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
             statements.addAll(doWhileStatements);
             statements.add(condition);
 
-            conditionValue = generateBlock(statements, true);
+            conditionValue = generateBlock(statements, true, continueLabel);
         }
         else {
             if (body != null) {
                 gen(body, Type.VOID_TYPE);
             }
-
+            v.mark(continueLabel);
             conditionValue = gen(condition);
         }
 
-        conditionValue.condJump(continueLabel, false, v);
+        conditionValue.condJump(beginLoopLabel, false, v);
         v.mark(breakLabel);
 
         blockStackElements.pop();
@@ -1411,6 +1412,10 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
     }
 
     private StackValue generateBlock(List<JetElement> statements, boolean lastStatementIsExpression) {
+        return generateBlock(statements, lastStatementIsExpression, null);
+    }
+
+    private StackValue generateBlock(List<JetElement> statements, boolean lastStatementIsExpression, Label labelBeforeLastExpression) {
         Label blockEnd = new Label();
 
         List<Function<StackValue, Void>> leaveTasks = Lists.newArrayList();
@@ -1443,6 +1448,9 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
             }
 
             boolean isExpression = !iterator.hasNext() && lastStatementIsExpression;
+            if (isExpression && labelBeforeLastExpression != null) {
+                v.mark(labelBeforeLastExpression);
+            }
 
             StackValue result = isExpression ? gen(statement) : genStatement(statement);
 

compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilder.java

@@ -52,6 +52,8 @@ public interface JetControlFlowBuilder {
     Label getEntryPoint(@NotNull JetElement labelElement);
     @NotNull
     Label getExitPoint(@NotNull JetElement labelElement);
+    @NotNull
+    Label getConditionEntryPoint(@NotNull JetElement labelElement);
 
     // Declarations
     void declareParameter(@NotNull JetParameter parameter);

compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowBuilderAdapter.java

@@ -183,6 +183,12 @@ public abstract class JetControlFlowBuilderAdapter implements JetControlFlowBuil
         return getDelegateBuilder().getExitPoint(labelElement);
     }
 
+    @NotNull
+    @Override
+    public Label getConditionEntryPoint(@NotNull JetElement labelElement) {
+        return getDelegateBuilder().getConditionEntryPoint(labelElement);
+    }
+
     @Override
     public LoopInfo enterLoop(@NotNull JetExpression expression, @Nullable Label loopExitPoint, Label conditionEntryPoint) {
         return getDelegateBuilder().enterLoop(expression, loopExitPoint, conditionEntryPoint);

compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java

@@ -953,7 +953,11 @@ public class JetControlFlowProcessor {
             JetElement loop = getCorrespondingLoop(expression);
             if (loop != null) {
                 checkJumpDoesNotCrossFunctionBoundary(expression, loop);
-                builder.jump(builder.getEntryPoint(loop), expression);
+                if (loop instanceof JetDoWhileExpression) {
+                    builder.jump(builder.getConditionEntryPoint(loop), expression);
+                } else {
+                    builder.jump(builder.getEntryPoint(loop), expression);
+                }
             }
         }
 

compiler/frontend/src/org/jetbrains/jet/lang/cfg/pseudocode/JetControlFlowInstructionsGenerator.java

@@ -200,6 +200,14 @@ public class JetControlFlowInstructionsGenerator extends JetControlFlowBuilderAd
             return elementToBlockInfo.get(labelElement).getEntryPoint();
         }
 
+        @NotNull
+        @Override
+        public Label getConditionEntryPoint(@NotNull JetElement labelElement) {
+            BreakableBlockInfo blockInfo = elementToBlockInfo.get(labelElement);
+            assert blockInfo instanceof LoopInfo : "expected LoopInfo for " + labelElement.getText() ;
+            return ((LoopInfo)blockInfo).getConditionEntryPoint();
+        }
+
         @NotNull
         @Override
         public Label getExitPoint(@NotNull JetElement labelElement) {

compiler/testData/codegen/box/controlStructures/doWhileWithContinue.kt

@@ -0,0 +1,21 @@
+fun box(): String {
+    var i = 0
+    do {
+        if (i++ > 100) break;
+        continue;
+    } while(false)
+    if (i != 1) return "Fail 1, expected 1, but $i"
+
+    i = 0
+    do {
+        if (i++ > 100) break;
+        continue;
+    } while(i<10)
+    if (i != 10) return "Fail 2, expected 10, but $i"
+
+    i = 0
+    do continue while(i++<10)
+    if (i != 11) return "Fail 3, expected 11, but $i"
+
+    return "OK"
+}

compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java

@@ -1468,6 +1468,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest("compiler/testData/codegen/box/controlStructures/doWhileFib.kt");
         }
         
+        @TestMetadata("doWhileWithContinue.kt")
+        public void testDoWhileWithContinue() throws Exception {
+            doTest("compiler/testData/codegen/box/controlStructures/doWhileWithContinue.kt");
+        }
+        
         @TestMetadata("emptyDoWhile.kt")
         public void testEmptyDoWhile() throws Exception {
             doTest("compiler/testData/codegen/box/controlStructures/emptyDoWhile.kt");