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* Copyright (c) 2010, 2016, 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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.
*
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package jdk.nashorn.internal.ir.debug;
import java.lang.reflect.Field;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Deque;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import jdk.nashorn.internal.ir.BinaryNode;
import jdk.nashorn.internal.ir.Block;
import jdk.nashorn.internal.ir.Expression;
import jdk.nashorn.internal.ir.IdentNode;
import jdk.nashorn.internal.ir.Node;
import jdk.nashorn.internal.ir.Statement;
import jdk.nashorn.internal.ir.Symbol;
import jdk.nashorn.internal.ir.Terminal;
import jdk.nashorn.internal.ir.TernaryNode;
import jdk.nashorn.internal.ir.annotations.Ignore;
import jdk.nashorn.internal.ir.annotations.Reference;
import jdk.nashorn.internal.parser.Token;
import jdk.nashorn.internal.runtime.Context;
import jdk.nashorn.internal.runtime.Debug;
/**
* AST-as-text visualizer. Sometimes you want tree form and not source
* code. This works for both lowered and unlowered IR
*
* see the flags --print-ast and --print-ast-lower
*/
public final class ASTWriter {
private static final ClassValue<Field[]> accessibleFields = new ClassValue<Field[]>() {
@Override
protected Field[] computeValue(final Class<?> type) {
final Field[] fields = type.getDeclaredFields();
for(final Field f: fields) {
f.setAccessible(true);
}
return fields;
}
};
/** Root node from which to start the traversal */
private final Node root;
private static final int TABWIDTH = 4;
/**
* Constructor
* @param root root of the AST to visualize
*/
public ASTWriter(final Node root) {
this.root = root;
}
/**
* Use the ASTWriter by instantiating it and retrieving its String
* representation
*
* @return the string representation of the AST
*/
@Override
public String toString() {
final StringBuilder sb = new StringBuilder();
printAST(sb, null, null, "root", root, 0);
return sb.toString();
}
/**
* Return the visited nodes in an ordered list
* @return the list of nodes in order
*/
public Node[] toArray() {
final List<Node> preorder = new ArrayList<>();
printAST(new StringBuilder(), preorder, null, "root", root, 0);
return preorder.toArray(new Node[0]);
}
@SuppressWarnings("unchecked")
private void printAST(final StringBuilder sb, final List<Node> preorder, final Field field, final String name, final Node node, final int indent) {
ASTWriter.indent(sb, indent);
if (node == null) {
sb.append("[Object ");
sb.append(name);
sb.append(" null]\n");
return;
}
if (preorder != null) {
preorder.add(node);
}
final boolean isReference = field != null && field.isAnnotationPresent(Reference.class);
final Class<?> clazz = node.getClass();
String type = clazz.getName();
type = type.substring(type.lastIndexOf('.') + 1, type.length());
int truncate = type.indexOf("Node");
if (truncate == -1) {
truncate = type.indexOf("Statement");
}
if (truncate != -1) {
type = type.substring(0, truncate);
}
type = type.toLowerCase();
if (isReference) {
type = "ref: " + type;
}
final Symbol symbol;
if (node instanceof IdentNode) {
symbol = ((IdentNode)node).getSymbol();
} else {
symbol = null;
}
if (symbol != null) {
type += ">" + symbol;
}
if (node instanceof Block && ((Block)node).needsScope()) {
type += " <scope>";
}
final List<Field> children = new LinkedList<>();
if (!isReference) {
enqueueChildren(node, clazz, children);
}
String status = "";
if (node instanceof Terminal && ((Terminal)node).isTerminal()) {
status += " Terminal";
}
if (node instanceof Statement && ((Statement)node).hasGoto()) {
status += " Goto ";
}
if (symbol != null) {
status += symbol;
}
status = status.trim();
if (!"".equals(status)) {
status = " [" + status + "]";
}
if (symbol != null) {
String tname = ((Expression)node).getType().toString();
if (tname.indexOf('.') != -1) {
tname = tname.substring(tname.lastIndexOf('.') + 1, tname.length());
}
status += " (" + tname + ")";
}
status += " @" + Debug.id(node);
if (children.isEmpty()) {
sb.append("[").
append(type).
append(' ').
append(name).
append(" = '").
append(node).
append("'").
append(status).
append("] ").
append('\n');
} else {
sb.append("[").
append(type).
append(' ').
append(name).
append(' ').
append(Token.toString(node.getToken())).
append(status).
append("]").
append('\n');
for (final Field child : children) {
if (child.isAnnotationPresent(Ignore.class)) {
continue;
}
Object value;
try {
value = child.get(node);
} catch (final IllegalArgumentException | IllegalAccessException e) {
Context.printStackTrace(e);
return;
}
if (value instanceof Node) {
printAST(sb, preorder, child, child.getName(), (Node)value, indent + 1);
} else if (value instanceof Collection) {
int pos = 0;
ASTWriter.indent(sb, indent + 1);
sb.append('[').
append(child.getName()).
append("[0..").
append(((Collection<Node>)value).size()).
append("]]").
append('\n');
for (final Node member : (Collection<Node>)value) {
printAST(sb, preorder, child, child.getName() + "[" + pos++ + "]", member, indent + 2);
}
}
}
}
}
private static void enqueueChildren(final Node node, final Class<?> nodeClass, final List<Field> children) {
final Deque<Class<?>> stack = new ArrayDeque<>();
/**
* Here is some ugliness that can be overcome by proper ChildNode annotations
* with proper orders. Right now we basically sort all classes up to Node
* with super class first, as this often is the natural order, e.g. base
* before index for an IndexNode.
*
* Also there are special cases as this is not true for UnaryNodes(lhs) and
* BinaryNodes extends UnaryNode (with lhs), and TernaryNodes.
*
* TODO - generalize traversal with an order built on annotations and this
* will go away.
*/
Class<?> clazz = nodeClass;
do {
stack.push(clazz);
clazz = clazz.getSuperclass();
} while (clazz != null);
if (node instanceof TernaryNode) {
// HACK juggle "third"
stack.push(stack.removeLast());
}
// HACK change operator order for BinaryNodes to get lhs first.
final Iterator<Class<?>> iter = node instanceof BinaryNode ? stack.descendingIterator() : stack.iterator();
while (iter.hasNext()) {
final Class<?> c = iter.next();
for (final Field f : accessibleFields.get(c)) {
try {
final Object child = f.get(node);
if (child == null) {
continue;
}
if (child instanceof Node) {
children.add(f);
} else if (child instanceof Collection) {
if (!((Collection<?>)child).isEmpty()) {
children.add(f);
}
}
} catch (final IllegalArgumentException | IllegalAccessException e) {
return;
}
}
}
}
private static void indent(final StringBuilder sb, final int indent) {
for (int i = 0; i < indent; i++) {
for (int j = 0; j < TABWIDTH; j++) {
sb.append(' ');
}
}
}
}