8134490: Dead var statement evacuation incorrectly descends into nested functions
authorattila
Fri, 25 Sep 2015 12:46:53 +0200
changeset 32785 3ed9323fb0cc
parent 32784 f7e0a3e05aa1
child 32786 dedf2b6ea495
8134490: Dead var statement evacuation incorrectly descends into nested functions Reviewed-by: hannesw, mhaupt
nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/FindScopeDepths.java
nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/Lower.java
nashorn/test/script/basic/JDK-8134490.js
--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/FindScopeDepths.java	Fri Sep 25 16:01:54 2015 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/FindScopeDepths.java	Fri Sep 25 12:46:53 2015 +0200
@@ -275,15 +275,11 @@
         final Set<Symbol> symbols = new HashSet<>();
         block.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) {
             @Override
-            public final boolean enterDefault(final Node node) {
-                if (!compiler.isOnDemandCompilation()) {
-                    if (node instanceof IdentNode) {
-                        final Symbol symbol = ((IdentNode)node).getSymbol();
-                        if (symbol != null && symbol.isScope()) {
-                            //if this is an internal symbol, skip it.
-                            symbols.add(symbol);
-                        }
-                    }
+            public boolean enterIdentNode(final IdentNode identNode) {
+                final Symbol symbol = identNode.getSymbol();
+                if (symbol != null && symbol.isScope()) {
+                    //if this is an internal symbol, skip it.
+                    symbols.add(symbol);
                 }
                 return true;
             }
--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/Lower.java	Fri Sep 25 16:01:54 2015 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/Lower.java	Fri Sep 25 12:46:53 2015 +0200
@@ -124,9 +124,18 @@
                         statement.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) {
                             @Override
                             public boolean enterVarNode(final VarNode varNode) {
+                                // We can't entirely eliminate dead statements, as var declarations are scoped
+                                // to the whole function so we need to preserve them although without
+                                // initializers.
                                 newStatements.add(varNode.setInit(null));
                                 return false;
                             }
+
+                            @Override
+                            public boolean enterFunctionNode(final FunctionNode functionNode) {
+                                // Don't descend into nested functions when searching for VarNodes, though.
+                                return false;
+                            }
                         });
                     }
                 }
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8134490.js	Fri Sep 25 12:46:53 2015 +0200
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2015 Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ * 
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ * 
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ * 
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ * 
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * JDK-8134490: Dead var statement evacuation incorrectly descends into nested functions
+ *
+ * @test
+ * @run
+ */
+
+var v1; 
+
+function f1() 
+{ 
+v1 = 1; 
+return true; 
+(function () { var v1; })(); 
+} 
+
+f1(); 
+// If it executes without throwing an exception in code generator, it's working.