Merge pull request #555 from JetBrains/rr/yole/putfield-null

Don't generate redundant initializers for 'var' properties.

compiler/backend/src/org/jetbrains/kotlin/codegen/MemberCodegen.java

@@ -37,8 +37,12 @@ import org.jetbrains.kotlin.name.SpecialNames;
 import org.jetbrains.kotlin.psi.*;
 import org.jetbrains.kotlin.resolve.BindingContext;
 import org.jetbrains.kotlin.resolve.BindingContextUtils;
+import org.jetbrains.kotlin.resolve.BindingTrace;
+import org.jetbrains.kotlin.resolve.TemporaryBindingTrace;
 import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall;
 import org.jetbrains.kotlin.resolve.constants.CompileTimeConstant;
+import org.jetbrains.kotlin.resolve.constants.IntegerValueTypeConstant;
+import org.jetbrains.kotlin.resolve.constants.evaluate.ConstantExpressionEvaluator;
 import org.jetbrains.kotlin.storage.LockBasedStorageManager;
 import org.jetbrains.kotlin.storage.NotNullLazyValue;
 import org.jetbrains.kotlin.types.ErrorUtils;
@@ -313,14 +317,25 @@ public abstract class MemberCodegen<T extends JetElement/* TODO: & JetDeclaratio
         PropertyDescriptor propertyDescriptor = (PropertyDescriptor) bindingContext.get(VARIABLE, property);
         assert propertyDescriptor != null;
 
-        CompileTimeConstant<?> compileTimeValue = propertyDescriptor.getCompileTimeInitializer();
+        JetExpression initializer = property.getInitializer();
+
+        CompileTimeConstant<?> initializerValue;
+        if (property.isVar() && initializer != null) {
+            BindingTrace tempTrace = TemporaryBindingTrace.create(state.getBindingTrace(), "property initializer");
+            initializerValue = ConstantExpressionEvaluator.OBJECT$.evaluate(initializer, tempTrace, propertyDescriptor.getType());
+        }
+        else {
+            initializerValue = propertyDescriptor.getCompileTimeInitializer();
+        }
         // we must write constant values for fields in light classes,
         // because Java's completion for annotation arguments uses this information
-        if (compileTimeValue == null) return state.getClassBuilderMode() != ClassBuilderMode.LIGHT_CLASSES;
+        if (initializerValue == null) return state.getClassBuilderMode() != ClassBuilderMode.LIGHT_CLASSES;
 
         //TODO: OPTIMIZATION: don't initialize static final fields
 
-        Object value = compileTimeValue.getValue();
+        Object value = initializerValue instanceof IntegerValueTypeConstant
+            ? ((IntegerValueTypeConstant) initializerValue).getValue(propertyDescriptor.getType())
+            : initializerValue.getValue();
         JetType jetType = getPropertyOrDelegateType(property, propertyDescriptor);
         Type type = typeMapper.mapType(jetType);
         return !skipDefaultValue(propertyDescriptor, value, type);

compiler/testData/codegen/bytecodeText/redundantInitializer.kt

@@ -0,0 +1,7 @@
+package a
+
+class A {
+    private var x: String? = null
+}
+
+// 0 PUTFIELD

compiler/testData/codegen/bytecodeText/redundantInitializerNumber.kt

@@ -0,0 +1,7 @@
+package a
+
+class A {
+    private var x: Int = 0
+}
+
+// 0 PUTFIELD

compiler/tests/org/jetbrains/kotlin/codegen/BytecodeTextTestGenerated.java

@@ -181,6 +181,18 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
         doTest(fileName);
     }
 
+    @TestMetadata("redundantInitializer.kt")
+    public void testRedundantInitializer() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/redundantInitializer.kt");
+        doTest(fileName);
+    }
+
+    @TestMetadata("redundantInitializerNumber.kt")
+    public void testRedundantInitializerNumber() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/redundantInitializerNumber.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("stringBuilderAppend.kt")
     public void testStringBuilderAppend() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/stringBuilderAppend.kt");