Optimize more redundant kotlin/jvm/internal/Refs

The number of initializations of the `value` field before the live range
begins does not really matter so long as we insert a write of a default
value to the local if there were none.

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

@@ -1081,27 +1081,23 @@ public class AsmUtil {
     }
 
     public static void pushDefaultValueOnStack(@NotNull Type type, @NotNull InstructionAdapter v) {
-        if (type.getSort() == Type.OBJECT || type.getSort() == Type.ARRAY) {
-            v.aconst(null);
-        }
-        else {
-            pushDefaultPrimitiveValueOnStack(type, v);
-        }
+        v.visitInsn(defaultValueOpcode(type));
     }
 
-    public static void pushDefaultPrimitiveValueOnStack(@NotNull Type type, @NotNull InstructionAdapter v) {
+    public static int defaultValueOpcode(@NotNull Type type) {
+        if (type.getSort() == Type.OBJECT || type.getSort() == Type.ARRAY) {
+            return ACONST_NULL;
+        }
         if (type.getSort() == Type.FLOAT) {
-            v.fconst(0);
+            return FCONST_0;
         }
-        else if (type.getSort() == Type.DOUBLE) {
-            v.dconst(0);
+        if (type.getSort() == Type.DOUBLE) {
+            return DCONST_0;
         }
-        else if (type.getSort() == Type.LONG) {
-            v.lconst(0);
-        }
-        else {
-            v.iconst(0);
+        if (type.getSort() == Type.LONG) {
+            return LCONST_0;
         }
+        return ICONST_0;
     }
 
     public static boolean isInstancePropertyWithStaticBackingField(@NotNull PropertyDescriptor propertyDescriptor) {

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

@@ -636,11 +636,8 @@ public abstract class StackValue {
             if (toType.equals(UNIT_TYPE) || toType.equals(OBJECT_TYPE)) {
                 putUnitInstance(v);
             }
-            else if (toType.getSort() == Type.OBJECT || toType.getSort() == Type.ARRAY) {
-                v.aconst(null);
-            }
             else {
-                pushDefaultPrimitiveValueOnStack(toType, v);
+                pushDefaultValueOnStack(toType, v);
             }
         }
         else if (toType.equals(UNIT_TYPE)) {

compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/CapturedVarsOptimizationMethodTransformer.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.codegen.optimization
 
 import org.jetbrains.kotlin.builtins.PrimitiveType
+import org.jetbrains.kotlin.codegen.AsmUtil
 import org.jetbrains.kotlin.codegen.optimization.common.*
 import org.jetbrains.kotlin.codegen.optimization.fixStack.peek
 import org.jetbrains.kotlin.codegen.optimization.fixStack.top
@@ -207,13 +208,6 @@ class CapturedVarsOptimizationMethodTransformer : MethodTransformer() {
                     refValue.localVarIndex = localVar.index
                 }
 
-                val startIndex = localVar.start.getIndex()
-                val initFieldInsns = refValue.putFieldInsns.filter { it.getIndex() < startIndex }
-                if (initFieldInsns.size != 1) {
-                    refValue.hazard = true
-                    continue
-                }
-
                 val cleanInstructions = findCleanInstructions(refValue, oldVarIndex, methodNode.instructions)
                 if (cleanInstructions.size > 1) {
                     refValue.hazard = true
@@ -227,14 +221,14 @@ class CapturedVarsOptimizationMethodTransformer : MethodTransformer() {
             return InsnSequence(instructions).filterIsInstance<VarInsnNode>().filter {
                 it.opcode == Opcodes.ASTORE && it.`var` == oldVarIndex
             }.filter {
-                    it.previous?.opcode == Opcodes.ACONST_NULL
-                }.filter {
-                    val operationIndex = instructions.indexOf(it)
-                    val localVariableNode = refValue.localVar!!
-                    instructions.indexOf(localVariableNode.start) < operationIndex && operationIndex < instructions.indexOf(
-                        localVariableNode.end
-                    )
-                }.toList()
+                it.previous?.opcode == Opcodes.ACONST_NULL
+            }.filter {
+                val operationIndex = instructions.indexOf(it)
+                val localVariableNode = refValue.localVar!!
+                instructions.indexOf(localVariableNode.start) < operationIndex && operationIndex < instructions.indexOf(
+                    localVariableNode.end
+                )
+            }.toList()
         }
 
         private fun rewrite() {
@@ -250,9 +244,17 @@ class CapturedVarsOptimizationMethodTransformer : MethodTransformer() {
 
         private fun rewriteRefValue(capturedVar: CapturedVarDescriptor) {
             methodNode.instructions.run {
-                capturedVar.localVar!!.let {
-                    it.signature = null
-                    it.desc = capturedVar.valueType.descriptor
+                val localVar = capturedVar.localVar!!
+                localVar.signature = null
+                localVar.desc = capturedVar.valueType.descriptor
+
+                val loadOpcode = capturedVar.valueType.getOpcode(Opcodes.ILOAD)
+                val storeOpcode = capturedVar.valueType.getOpcode(Opcodes.ISTORE)
+
+                if (capturedVar.putFieldInsns.none { it.getIndex() < localVar.start.getIndex() }) {
+                    // variable needs to be initialized before its live range can begin
+                    insertBefore(capturedVar.newInsn, InsnNode(AsmUtil.defaultValueOpcode(capturedVar.valueType)))
+                    insertBefore(capturedVar.newInsn, VarInsnNode(storeOpcode, capturedVar.localVarIndex))
                 }
 
                 remove(capturedVar.newInsn)
@@ -260,14 +262,8 @@ class CapturedVarsOptimizationMethodTransformer : MethodTransformer() {
                 capturedVar.stackInsns.forEach { remove(it) }
                 capturedVar.aloadInsns.forEach { remove(it) }
                 capturedVar.astoreInsns.forEach { remove(it) }
-
-                capturedVar.getFieldInsns.forEach {
-                    set(it, VarInsnNode(capturedVar.valueType.getOpcode(Opcodes.ILOAD), capturedVar.localVarIndex))
-                }
-
-                capturedVar.putFieldInsns.forEach {
-                    set(it, VarInsnNode(capturedVar.valueType.getOpcode(Opcodes.ISTORE), capturedVar.localVarIndex))
-                }
+                capturedVar.getFieldInsns.forEach { set(it, VarInsnNode(loadOpcode, capturedVar.localVarIndex)) }
+                capturedVar.putFieldInsns.forEach { set(it, VarInsnNode(storeOpcode, capturedVar.localVarIndex)) }
 
                 //after visiting block codegen tries to delete all allocated references:
                 // see ExpressionCodegen.addLeaveTaskToRemoveLocalVariableFromFrameMap

compiler/testData/codegen/bytecodeText/capturedVarsOptimization/capturedInChainOfInlineFuns.kt

@@ -1,6 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
-
 fun test() {
     var x = 0
     run {

compiler/testData/codegen/bytecodeText/capturedVarsOptimization/capturedInInlineOnly.kt

@@ -1,6 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
-
 fun test() {
     var x = 0
     run { ++x }

compiler/testData/codegen/bytecodeText/capturedVarsOptimization/capturedValInLambdaInitializedInside.kt

@@ -1,11 +1,4 @@
 // WITH_RUNTIME
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
-
-// In JVM IR, SharedVariablesLowering transforms `x` into a shared variable to be able to update it from a lambda,
-// which is a separate function (...$lambda-0).
-// If we keep the existing representation of lambda bodies as separate functions in JVM IR, the only viable option to fix this test
-// seems to support this case in the bytecode optimization pass CapturedVarsOptimizationMethodTransformer.
 
 fun box(): String {
     val x: String

compiler/testData/codegen/bytecodeText/capturedVarsOptimization/capturedVarsOfSize2.kt

@@ -1,6 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
-
 fun box(): String {
     var xl = 0L     // Long, size 2
     var xi = 0      // Int, size 1

compiler/testData/codegen/bytecodeText/capturedVarsOptimization/withStackNormalization.kt

@@ -1,6 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
-
 fun add(x: Int, y: Int) = x + y
 
 fun test() {

compiler/testData/codegen/bytecodeText/localInitializationLVT/boxing.kt

@@ -1,6 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
-
 fun test(): java.lang.Integer {
     val c: java.lang.Integer
     run {
@@ -10,4 +7,9 @@ fun test(): java.lang.Integer {
 }
 
 // 2 ASTORE 0
-// 1 LOCALVARIABLE c Ljava/lang/Integer; L1 L.* 0
+
+// JVM_TEMPLATES
+// 1 LOCALVARIABLE c Ljava/lang/Integer;
+
+// JVM_IR_TEMPLATES
+// 1 LOCALVARIABLE c Ljava/lang/Object;

compiler/testData/codegen/bytecodeText/localInitializationLVT/boxingVar.kt

@@ -6,5 +6,5 @@ fun test(): java.lang.Integer {
     return c
 }
 
-// 1 ASTORE 0
-// 1 LOCALVARIABLE c Lkotlin/jvm/internal/Ref\$ObjectRef; L1 L.* 0
+// 2 ASTORE 0
+// 1 LOCALVARIABLE c Ljava/lang/Object;

compiler/testData/codegen/bytecodeText/localInitializationLVT/generics.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-
 inline fun <reified T> foo(default: T): T {
     val t: T
     run {
@@ -13,6 +11,6 @@ fun test() {
 }
 
 // two in foo and two in test
-
 // 4 ASTORE 2
-// 1 LOCALVARIABLE t\$iv Ljava/lang/Object; L3 L.* 2
+// 1 LOCALVARIABLE t Ljava/lang/Object;
+// 1 LOCALVARIABLE t\$iv Ljava/lang/Object;

compiler/testData/codegen/bytecodeText/localInitializationLVT/genericsVar.kt

@@ -1,4 +1,3 @@
-
 inline fun <reified T> foo(default: T): T {
     var t: T
     run {
@@ -12,6 +11,6 @@ fun test() {
 }
 
 // two in foo and two in test
-
-// 2 ASTORE 2
-// 1 LOCALVARIABLE t\$iv Lkotlin/jvm/internal/Ref\$ObjectRef; L3 L.* 2
+// 4 ASTORE 2
+// 1 LOCALVARIABLE t Ljava/lang/Object;
+// 1 LOCALVARIABLE t\$iv Ljava/lang/Object;

compiler/testData/codegen/bytecodeText/localInitializationLVT/inlineClass.kt

@@ -1,5 +1,5 @@
 // IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
+// TODO: JVM_IR uses ObjectRef instead of IntRef for the value
 
 fun test(): UInt {
     val c: UInt
@@ -10,4 +10,4 @@ fun test(): UInt {
 }
 
 // 2 ISTORE 0
-// 1 LOCALVARIABLE c I L1 L.* 0
+// 1 LOCALVARIABLE c I

compiler/testData/codegen/bytecodeText/localInitializationLVT/inlineClassVar.kt

@@ -1,5 +1,5 @@
 // IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
+// TODO: JVM_IR uses ObjectRef instead of IntRef for the value
 
 fun test(): UInt {
     var c: UInt
@@ -9,5 +9,5 @@ fun test(): UInt {
     return c
 }
 
-// 1 ASTORE 0
-// 1 LOCALVARIABLE c Lkotlin/jvm/internal/Ref\$IntRef; L1 L.* 0
+// 2 ISTORE 0
+// 1 LOCALVARIABLE c I

compiler/testData/codegen/bytecodeText/localInitializationLVT/lateinit.kt

@@ -1,6 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
-
 fun test(): Char {
     lateinit var c: Any
     run {
@@ -9,5 +6,11 @@ fun test(): Char {
     return c as Char
 }
 
+// 1 LOCALVARIABLE c Ljava/lang/Object;
+
+// JVM_TEMPLATES
 // 2 ASTORE 0
-// 1 LOCALVARIABLE c Ljava/lang/Object; L1 L.* 0
+
+// JVM_IR_TEMPLATES
+// 3 ASTORE 0
+// *two* of them are after the start of c's live range

compiler/testData/codegen/bytecodeText/localInitializationLVT/run.kt

@@ -1,6 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36648 Captured variables not optimized in JVM_IR
-
 fun test(): Char {
     val c: Char
     run {
@@ -12,4 +9,4 @@ fun test(): Char {
 
 // The first on declaration, the other on initialization
 // 2 ISTORE 0
-// 1 LOCALVARIABLE c C L1 L.* 0
+// 1 LOCALVARIABLE c C

compiler/testData/codegen/bytecodeText/localInitializationLVT/runVar.kt

@@ -6,5 +6,5 @@ fun test(): Char {
     return c
 }
 
-// 1 ASTORE 0
-// 1 LOCALVARIABLE c Lkotlin/jvm/internal/Ref\$CharRef; L1 L.* 0
+// 2 ISTORE 0
+// 1 LOCALVARIABLE c C

compiler/testData/codegen/bytecodeText/nullCheckOptimization/localLateinit/checkedOnce.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36813 Support code generated by JVM_IR in redundant null check optimization
 fun almostAlwaysTrue() = true
 
 fun test() {

compiler/testData/codegen/bytecodeText/nullCheckOptimization/localLateinit/initialized.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36813 Support code generated by JVM_IR in redundant null check optimization
 fun test() {
     lateinit var z: String
     run {