From 173f1fc7d15e7381a16c7ccdc659821726e24584 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Steven=20Sch=C3=A4fer?= <stevenschaefer@google.com>
Date: Tue, 23 Jul 2019 13:59:56 +0200
Subject: [PATCH] Fix statement order in LocalDeclarationsLowering

Previously, the order of IrSetField statements in this lowering was
non-deterministic. This broke the inliner in the JVM backend which
expects statements to be in argument order.
---
 .../common/lower/LocalDeclarationsLowering.kt | 36 ++++++++++---------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LocalDeclarationsLowering.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LocalDeclarationsLowering.kt
index 5214faf992e..16b384b6428 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LocalDeclarationsLowering.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LocalDeclarationsLowering.kt
@@ -87,7 +87,7 @@ class LocalDeclarationsLowering(
         abstract val declaration: IrFunction
         abstract val transformedDeclaration: IrFunction
 
-        val capturedValueToParameter: MutableMap<IrValueDeclaration, IrValueParameter> = HashMap()
+        val capturedValueToParameter: MutableMap<IrValueDeclaration, IrValueParameter> = mutableMapOf()
 
         override fun irGet(startOffset: Int, endOffset: Int, valueDeclaration: IrValueDeclaration): IrExpression? {
             val parameter = capturedValueToParameter[valueDeclaration] ?: return null
@@ -114,7 +114,9 @@ class LocalDeclarationsLowering(
     private class LocalClassContext(val declaration: IrClass) : LocalContext() {
         lateinit var closure: Closure
 
-        val capturedValueToField: MutableMap<IrValueDeclaration, IrField> = HashMap()
+        // NOTE: This map is iterated over in `rewriteClassMembers` and we're relying on
+        // the deterministic iteration order that `mutableMapOf` provides.
+        val capturedValueToField: MutableMap<IrValueDeclaration, IrField> = mutableMapOf()
 
         override fun irGet(startOffset: Int, endOffset: Int, valueDeclaration: IrValueDeclaration): IrExpression? {
             val field = capturedValueToField[valueDeclaration] ?: return null
@@ -380,26 +382,26 @@ class LocalDeclarationsLowering(
 
             assert(constructorsCallingSuper.any()) { "Expected at least one constructor calling super; class: $irClass" }
 
-            localClassContext.capturedValueToField.forEach { (capturedValue, field) ->
-                val startOffset = irClass.startOffset
-                val endOffset = irClass.endOffset
-                irClass.declarations.add(field)
+            irClass.declarations += localClassContext.capturedValueToField.values
 
-                for (constructorContext in constructorsCallingSuper) {
-                    val blockBody = constructorContext.declaration.body as? IrBlockBody
-                        ?: throw AssertionError("Unexpected constructor body: ${constructorContext.declaration.body}")
-                    val capturedValueExpression = constructorContext.irGet(startOffset, endOffset, capturedValue)!!
-                    blockBody.statements.add(
-                        0,
+            for (constructorContext in constructorsCallingSuper) {
+                val blockBody = constructorContext.declaration.body as? IrBlockBody
+                    ?: throw AssertionError("Unexpected constructor body: ${constructorContext.declaration.body}")
+
+                // NOTE: It's important to set the fields for captured values in the same order as the arguments,
+                // since `AnonymousObjectTransformer` relies on this ordering.
+                blockBody.statements.addAll(
+                    0,
+                    localClassContext.capturedValueToField.map { (capturedValue, field) ->
                         IrSetFieldImpl(
-                            startOffset, endOffset, field.symbol,
-                            IrGetValueImpl(startOffset, endOffset, irClass.thisReceiver!!.symbol),
-                            capturedValueExpression,
+                            irClass.startOffset, irClass.endOffset, field.symbol,
+                            IrGetValueImpl(irClass.startOffset, irClass.endOffset, irClass.thisReceiver!!.symbol),
+                            constructorContext.irGet(irClass.startOffset, irClass.endOffset, capturedValue)!!,
                             context.irBuiltIns.unitType,
                             STATEMENT_ORIGIN_INITIALIZER_OF_FIELD_FOR_CAPTURED_VALUE
                         )
-                    )
-                }
+                    }
+                )
             }
         }