Prohibit from eliminating non-local temporary variables

js/js.inliner/src/org/jetbrains/kotlin/js/inline/clean/TemporaryAssignmentElimination.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.js.inline.clean
 import com.google.dart.compiler.backend.js.ast.*
 import com.google.dart.compiler.backend.js.ast.metadata.synthetic
 import org.jetbrains.kotlin.js.inline.util.canHaveSideEffect
+import org.jetbrains.kotlin.js.inline.util.collectDefinedNames
 import org.jetbrains.kotlin.js.inline.util.collectFreeVariables
 import org.jetbrains.kotlin.js.translate.utils.JsAstUtils
 
@@ -29,6 +30,7 @@ internal class TemporaryAssignmentElimination(private val root: JsBlock) {
     private val mappedUsages = mutableMapOf<JsName, Usage>()
     private val syntheticNames = mutableSetOf<JsName>()
     private var hasChanges = false
+    private val namesToProcess = mutableSetOf<JsName>()
 
     fun apply(): Boolean {
         analyze()
@@ -39,6 +41,8 @@ internal class TemporaryAssignmentElimination(private val root: JsBlock) {
     }
 
     private fun analyze() {
+        namesToProcess.addAll(collectDefinedNames(root))
+
         object : JsVisitorWithContextImpl() {
             override fun visit(x: JsReturn, ctx: JsContext<*>): Boolean {
                 val returnExpr = x.expression
@@ -253,6 +257,7 @@ internal class TemporaryAssignmentElimination(private val root: JsBlock) {
     private fun tryRecord(expr: JsExpression, usage: Usage): Boolean {
         if (expr !is JsNameRef) return false
         val name = expr.name ?: return false
+        if (name !in namesToProcess) return false
 
         usages[name] = usage
         return true

js/js.inliner/src/org/jetbrains/kotlin/js/inline/clean/TemporaryVariableElimination.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.js.inline.clean
 import com.google.dart.compiler.backend.js.ast.*
 import com.google.dart.compiler.backend.js.ast.metadata.synthetic
 import org.jetbrains.kotlin.js.inline.util.canHaveSideEffect
+import org.jetbrains.kotlin.js.inline.util.collectDefinedNames
 import org.jetbrains.kotlin.js.inline.util.collectFreeVariables
 import org.jetbrains.kotlin.js.translate.utils.JsAstUtils
 
@@ -28,6 +29,7 @@ internal class TemporaryVariableElimination(private val root: JsStatement) {
     private val definedValues = mutableMapOf<JsName, JsExpression>()
     private val temporary = mutableSetOf<JsName>()
     private var hasChanges = false
+    private val namesToProcess = mutableSetOf<JsName>()
 
     fun apply(): Boolean {
         analyze()
@@ -36,6 +38,8 @@ internal class TemporaryVariableElimination(private val root: JsStatement) {
     }
 
     private fun analyze() {
+        namesToProcess.addAll(collectDefinedNames(root))
+
         object : JsVisitorWithContextImpl() {
             val lastAssignedVars = mutableListOf<JsName>()
 
@@ -44,7 +48,7 @@ internal class TemporaryVariableElimination(private val root: JsStatement) {
                 if (name != null && x.qualifier == null) {
                     val expr = definedValues[name]
                     useVariable(name)
-                    if (lastAssignedVars.lastOrNull() == name) {
+                    if (lastAssignedVars.lastOrNull() == name && name in namesToProcess) {
                         lastAssignedVars.removeAt(lastAssignedVars.lastIndex)
                     }
                     else if (expr == null || expr.canHaveSideEffect()) {
@@ -95,7 +99,7 @@ internal class TemporaryVariableElimination(private val root: JsStatement) {
                     val (name, value) = assignment
                     assignVariable(name, value)
                     accept(value)
-                    if (x.synthetic) {
+                    if (x.synthetic && name in namesToProcess) {
                         temporary += name
                     }
                     else if (value.canHaveSideEffect()) {

js/js.tests/test/org/jetbrains/kotlin/js/test/optimizer/TemporaryAssignmentEliminationTest.kt

@@ -24,4 +24,6 @@ class TemporaryAssignmentEliminationTest : BasicOptimizerTest("temporary-assignm
     @Test fun returnStatement() = box()
 
     @Test fun declaration() = box()
+
+    @Test fun skipsGlobalDeclarations() = box()
 }

js/js.tests/test/org/jetbrains/kotlin/js/test/optimizer/TemporaryVariableEliminationTest.kt

@@ -22,4 +22,6 @@ class TemporaryVariableEliminationTest : BasicOptimizerTest("temporary-variable"
     @Test fun declaration() = box()
 
     @Test fun assignment() = box()
+
+    @Test fun skipsGlobalDeclarations() = box()
 }

js/js.translator/testData/js-optimizer/temporary-assignment/declaration.optimized.js

@@ -10,10 +10,10 @@ function test(n) {
 }
 
 function box() {
-    var result = test(20)
+    var result = test(20);
     if (result != 20) return "fail1: " + result;
 
-    result = test(-20)
+    result = test(-20);
     if (result != 20) return "fail2: " + result;
 
     return "OK"

js/js.translator/testData/js-optimizer/temporary-assignment/skipsGlobalDeclarations.optimized.js

@@ -0,0 +1,24 @@
+var $tmp;
+
+function test(n) {
+    if (n >= 0) {
+        $tmp = n;
+    }
+    else {
+        $tmp = -n;
+    }
+    var result = $tmp;
+    return result;
+}
+
+function box() {
+    var result = test(20);
+    if (result != 20) return "fail1: " + result;
+
+    result = test(-20);
+    if (result != 20) return "fail2: " + result;
+
+    if ($tmp != 20) return "fail3: " + result;
+
+    return "OK"
+}

js/js.translator/testData/js-optimizer/temporary-assignment/skipsGlobalDeclarations.original.js

@@ -0,0 +1,24 @@
+var $tmp;
+
+function test(n) {
+    if (n >= 0) {
+        $tmp = n;
+    }
+    else {
+        $tmp = -n;
+    }
+    var result = $tmp;
+    return result;
+}
+
+function box() {
+    var result = test(20);
+    if (result != 20) return "fail1: " + result;
+
+    result = test(-20);
+    if (result != 20) return "fail2: " + result;
+
+    if ($tmp != 20) return "fail3: " + result;
+
+    return "OK"
+}

js/js.translator/testData/js-optimizer/temporary-variable/skipsGlobalDeclarations.optimized.js

@@ -0,0 +1,14 @@
+var $tmp;
+
+function test(a, b, c) {
+    $tmp = a + b;
+    return $tmp + c;
+}
+
+function box() {
+    var result = test(2, 3, 4);
+    if (result != 9) return "fail1: " + result;
+    if ($tmp != 5) return "fail2: " + $tmp; 
+
+    return "OK"
+}

js/js.translator/testData/js-optimizer/temporary-variable/skipsGlobalDeclarations.original.js

@@ -0,0 +1,14 @@
+var $tmp;
+
+function test(a, b, c) {
+    $tmp = a + b;
+    return $tmp + c;
+}
+
+function box() {
+    var result = test(2, 3, 4);
+    if (result != 9) return "fail1: " + result;
+    if ($tmp != 5) return "fail2: " + $tmp; 
+
+    return "OK"
+}