Fix codegen of do-while condition

The condition of a do-while loop can use variables declared in the loop
(variables can only be declared inside a block). Previously this behaviour
caused crash because after the block was generated, all variables declared
inside that block were gone from myFrameMap

 #KT-3280 Fixed

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

@@ -55,7 +55,6 @@ import org.jetbrains.jet.lang.resolve.constants.CompileTimeConstant;
 import org.jetbrains.jet.lang.resolve.java.AsmTypeConstants;
 import org.jetbrains.jet.lang.resolve.java.JvmAbi;
 import org.jetbrains.jet.lang.resolve.java.JvmClassName;
-import org.jetbrains.jet.lang.resolve.java.JvmPrimitiveType;
 import org.jetbrains.jet.lang.resolve.scopes.receivers.*;
 import org.jetbrains.jet.lang.types.JetType;
 import org.jetbrains.jet.lang.types.checker.JetTypeChecker;
@@ -421,22 +420,38 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
 
     @Override
     public StackValue visitDoWhileExpression(JetDoWhileExpression expression, StackValue receiver) {
-        Label condition = new Label();
-        v.mark(condition);
+        Label continueLabel = new Label();
+        v.mark(continueLabel);
 
-        Label end = new Label();
+        Label breakLabel = new Label();
 
-        blockStackElements.push(new LoopBlockStackElement(end, condition, targetLabel(expression)));
+        blockStackElements.push(new LoopBlockStackElement(breakLabel, continueLabel, targetLabel(expression)));
 
-        gen(expression.getBody(), Type.VOID_TYPE);
+        JetExpression body = expression.getBody();
+        JetExpression condition = expression.getCondition();
+        StackValue conditionValue;
 
-        final StackValue conditionValue = gen(expression.getCondition());
-        conditionValue.condJump(condition, false, v);
+        if (body instanceof JetBlockExpression) {
+            // If body's a block, it can contain variable declarations which may be used in the condition of a do-while loop.
+            // We handle this case separately because otherwise such variable will be out of the frame map after the block ends
+            List<JetElement> doWhileStatements = ((JetBlockExpression) body).getStatements();
 
-        v.mark(end);
+            List<JetElement> statements = new ArrayList<JetElement>(doWhileStatements.size() + 1);
+            statements.addAll(doWhileStatements);
+            statements.add(condition);
+
+            conditionValue = generateBlock(statements, true);
+        }
+        else {
+            gen(body, Type.VOID_TYPE);
+            conditionValue = gen(condition);
+        }
+
+        conditionValue.condJump(continueLabel, false, v);
+        v.mark(breakLabel);
 
         blockStackElements.pop();
-        return StackValue.onStack(Type.VOID_TYPE);
+        return StackValue.none();
     }
 
     @Override

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

@@ -0,0 +1,15 @@
+fun box(): String {
+    var x = 0
+    do x++ while (x < 5)
+    if (x != 5) return "Fail 1 $x"
+    
+    var y = 0
+    do { y++ } while (y < 5)
+    if (y != 5) return "Fail 2 $y"
+    
+    var z = ""
+    do { z += z.length } while (z.length < 5)
+    if (z != "01234") return "Fail 3 $z"
+    
+    return "OK"
+}

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

@@ -0,0 +1,12 @@
+fun box(): String {
+    var fx = 1
+    var fy = 1
+    
+    do {
+        var tmp = fy
+        fy = fx + fy
+        fx = tmp
+    } while (fy < 100)
+    
+    return if (fy == 144) "OK" else "Fail $fx $fy"
+}

compiler/testData/codegen/box/controlStructures/kt3280.kt

@@ -0,0 +1,24 @@
+fun foo() {
+    var x = 0
+    do {
+        x++
+        var y = x + 5
+    } while (y < 10)
+    if (x != 5) throw AssertionError("$x")
+}
+
+fun bar() {
+    var b = false
+    do {
+        var x = "X"
+        var y = "Y"
+        b = true
+    } while (x + y != "XY")
+    if (!b) throw AssertionError()
+}
+
+fun box(): String {
+    foo()
+    bar()
+    return "OK"
+}

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

@@ -1012,6 +1012,16 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             blackBoxFileByFullPath("compiler/testData/codegen/box/controlStructures/continueToLabelInFor.kt");
         }
         
+        @TestMetadata("doWhile.kt")
+        public void testDoWhile() throws Exception {
+            blackBoxFileByFullPath("compiler/testData/codegen/box/controlStructures/doWhile.kt");
+        }
+        
+        @TestMetadata("doWhileFib.kt")
+        public void testDoWhileFib() throws Exception {
+            blackBoxFileByFullPath("compiler/testData/codegen/box/controlStructures/doWhileFib.kt");
+        }
+        
         @TestMetadata("finallyOnEmptyReturn.kt")
         public void testFinallyOnEmptyReturn() throws Exception {
             blackBoxFileByFullPath("compiler/testData/codegen/box/controlStructures/finallyOnEmptyReturn.kt");
@@ -1157,6 +1167,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             blackBoxFileByFullPath("compiler/testData/codegen/box/controlStructures/kt3273.kt");
         }
         
+        @TestMetadata("kt3280.kt")
+        public void testKt3280() throws Exception {
+            blackBoxFileByFullPath("compiler/testData/codegen/box/controlStructures/kt3280.kt");
+        }
+        
         @TestMetadata("kt416.kt")
         public void testKt416() throws Exception {
             blackBoxFileByFullPath("compiler/testData/codegen/box/controlStructures/kt416.kt");