From 8baae95531b36273b6e1188bb330f316b9d1346d Mon Sep 17 00:00:00 2001
From: Dmitry Jemerov <yole@jetbrains.com>
Date: Fri, 8 Jun 2012 17:58:09 +0200
Subject: [PATCH] if a shared variable is a result of the block, release it
 only after it has been put #KT-2151 Fixed

---
 .../jet/codegen/ExpressionCodegen.java          |  9 +++++++--
 .../org/jetbrains/jet/codegen/StackValue.java   | 17 +++++++++++++++--
 compiler/testData/codegen/regressions/kt2151.kt | 11 +++++++++++
 .../jetbrains/jet/codegen/ClosuresGenTest.java  |  4 ++++
 4 files changed, 37 insertions(+), 4 deletions(-)
 create mode 100644 compiler/testData/codegen/regressions/kt2151.kt

diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java b/compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
index fe0007114ec..5218d25a1fa 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
@@ -917,8 +917,13 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
                 final Type sharedVarType = typeMapper.getSharedVarType(variableDescriptor);
                 final Type type = sharedVarType != null ? sharedVarType : asmType(variableDescriptor.getType());
                 if(sharedVarType != null) {
-                    v.aconst(null);
-                    v.store(index, TYPE_OBJECT);
+                    if (answer instanceof StackValue.Shared && index == ((StackValue.Shared) answer).getIndex()) {
+                        ((StackValue.Shared) answer).releaseOnPut();
+                    }
+                    else {
+                        v.aconst(null);
+                        v.store(index, TYPE_OBJECT);
+                    }
                 }
 
                 v.visitLocalVariable(var.getName(), type.getDescriptor(), null, blockStart, blockEnd, index);
diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/StackValue.java b/compiler/backend/src/org/jetbrains/jet/codegen/StackValue.java
index 0ec3c7b2bf5..8b06d756332 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/StackValue.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/StackValue.java
@@ -924,20 +924,33 @@ public abstract class StackValue {
 
     public static class Shared extends StackValue {
         private final int index;
+        private boolean isReleaseOnPut = false;
 
         public Shared(int index, Type type) {
             super(type);
             this.index = index;
         }
 
+        public void releaseOnPut() {
+            isReleaseOnPut = true;
+        }
+
+        public int getIndex() {
+            return index;
+        }
+
         @Override
         public void put(Type type, InstructionAdapter v) {
             v.load(index, JetTypeMapper.TYPE_OBJECT);
             Type refType = refType(this.type);
             Type sharedType = sharedTypeForType(this.type);
             v.visitFieldInsn(Opcodes.GETFIELD, sharedType.getInternalName(), "ref", refType.getDescriptor());
-            StackValue.onStack(refType).coerce(this.type, v);
-            StackValue.onStack(this.type).coerce(type, v);
+            coerce(refType, this.type, v);
+            coerce(this.type, type, v);
+            if (isReleaseOnPut) {
+                v.aconst(null);
+                v.store(index, JetTypeMapper.TYPE_OBJECT);
+            }
         }
 
         @Override
diff --git a/compiler/testData/codegen/regressions/kt2151.kt b/compiler/testData/codegen/regressions/kt2151.kt
new file mode 100644
index 00000000000..5b0da23f6ea
--- /dev/null
+++ b/compiler/testData/codegen/regressions/kt2151.kt
@@ -0,0 +1,11 @@
+fun foo(): String {
+    return if (true) {
+        var x = "OK"
+        fun foo() { x += "fail" }
+        x
+    } else "fail"
+}
+
+fun box(): String {
+    return foo()
+}
diff --git a/compiler/tests/org/jetbrains/jet/codegen/ClosuresGenTest.java b/compiler/tests/org/jetbrains/jet/codegen/ClosuresGenTest.java
index f83c43d5fcd..e5591cdc5c3 100644
--- a/compiler/tests/org/jetbrains/jet/codegen/ClosuresGenTest.java
+++ b/compiler/tests/org/jetbrains/jet/codegen/ClosuresGenTest.java
@@ -62,4 +62,8 @@ public class ClosuresGenTest extends CodegenTestCase {
     public void testEnclosingThis() throws Exception {
         blackBoxFile("classes/enclosingThis.jet");
     }
+
+    public void testKt2151() {
+        blackBoxFile("regressions/kt2151.kt");
+    }
 }