1 /*
2 * Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.nashorn.internal.codegen;
27
28 import static jdk.nashorn.internal.codegen.CompilerConstants.ARGUMENTS_VAR;
29 import static jdk.nashorn.internal.codegen.CompilerConstants.EXPLODED_ARGUMENT_PREFIX;
30
31 import java.lang.invoke.MethodType;
32 import java.net.URL;
33 import java.util.ArrayDeque;
34 import java.util.ArrayList;
35 import java.util.Deque;
36 import java.util.HashSet;
37 import java.util.List;
38 import java.util.Set;
39 import jdk.nashorn.internal.ir.AccessNode;
40 import jdk.nashorn.internal.ir.CallNode;
41 import jdk.nashorn.internal.ir.Expression;
42 import jdk.nashorn.internal.ir.FunctionNode;
43 import jdk.nashorn.internal.ir.IdentNode;
44 import jdk.nashorn.internal.ir.Node;
45 import jdk.nashorn.internal.ir.visitor.SimpleNodeVisitor;
46 import jdk.nashorn.internal.objects.Global;
47 import jdk.nashorn.internal.runtime.Context;
48 import jdk.nashorn.internal.runtime.logging.DebugLogger;
49 import jdk.nashorn.internal.runtime.logging.Loggable;
50 import jdk.nashorn.internal.runtime.logging.Logger;
51 import jdk.nashorn.internal.runtime.options.Options;
52
53 /**
54 * An optimization that attempts to turn applies into calls. This pattern
55 * is very common for fake class instance creation, and apply
56 * introduces expensive args collection and boxing
57 *
58 * <pre>
59 * var Class = {
60 * create: function() {
61 * return function() { //vararg
62 * this.initialize.apply(this, arguments);
63 * }
64 * }
65 * };
66 *
67 * Color = Class.create();
68 *
69 * Color.prototype = {
70 * red: 0, green: 0, blue: 0,
71 * initialize: function(r,g,b) {
72 * this.red = r;
73 * this.green = g;
74 * this.blue = b;
75 * }
76 * }
77 *
78 * new Color(17, 47, 11);
79 * </pre>
80 */
81
82 @Logger(name="apply2call")
83 public final class ApplySpecialization extends SimpleNodeVisitor implements Loggable {
84
85 private static final boolean USE_APPLY2CALL = Options.getBooleanProperty("nashorn.apply2call", true);
86
87 private final DebugLogger log;
88
89 private final Compiler compiler;
90
91 private final Set<Integer> changed = new HashSet<>();
92
93 private final Deque<List<IdentNode>> explodedArguments = new ArrayDeque<>();
94
95 private final Deque<MethodType> callSiteTypes = new ArrayDeque<>();
96
97 private static final String ARGUMENTS = ARGUMENTS_VAR.symbolName();
98
99 /**
100 * Apply specialization optimization. Try to explode arguments and call
101 * applies as calls if they just pass on the "arguments" array and
102 * "arguments" doesn't escape.
103 *
104 * @param compiler compiler
105 */
106 public ApplySpecialization(final Compiler compiler) {
107 this.compiler = compiler;
108 this.log = initLogger(compiler.getContext());
109 }
110
111 @Override
112 public DebugLogger getLogger() {
113 return log;
114 }
115
116 @Override
117 public DebugLogger initLogger(final Context context) {
118 return context.getLogger(this.getClass());
119 }
120
121 @SuppressWarnings("serial")
122 private static class TransformFailedException extends RuntimeException {
123 TransformFailedException(final FunctionNode fn, final String message) {
124 super(massageURL(fn.getSource().getURL()) + '.' + fn.getName() + " => " + message, null, false, false);
125 }
126 }
127
128 @SuppressWarnings("serial")
129 private static class AppliesFoundException extends RuntimeException {
130 AppliesFoundException() {
131 super("applies_found", null, false, false);
132 }
133 }
134
135 private static final AppliesFoundException HAS_APPLIES = new AppliesFoundException();
136
137 private boolean hasApplies(final FunctionNode functionNode) {
138 try {
139 functionNode.accept(new SimpleNodeVisitor() {
140 @Override
141 public boolean enterFunctionNode(final FunctionNode fn) {
142 return fn == functionNode;
143 }
144
145 @Override
146 public boolean enterCallNode(final CallNode callNode) {
147 if (isApply(callNode)) {
148 throw HAS_APPLIES;
149 }
150 return true;
151 }
152 });
153 } catch (final AppliesFoundException e) {
154 return true;
155 }
156
157 log.fine("There are no applies in ", DebugLogger.quote(functionNode.getName()), " - nothing to do.");
158 return false; // no applies
159 }
160
161 /**
162 * Arguments may only be used as args to the apply. Everything else is disqualified
163 * We cannot control arguments if they escape from the method and go into an unknown
164 * scope, thus we are conservative and treat any access to arguments outside the
165 * apply call as a case of "we cannot apply the optimization".
166 */
167 private static void checkValidTransform(final FunctionNode functionNode) {
168
169 final Set<Expression> argumentsFound = new HashSet<>();
170 final Deque<Set<Expression>> stack = new ArrayDeque<>();
171
172 //ensure that arguments is only passed as arg to apply
173 functionNode.accept(new SimpleNodeVisitor() {
174
175 private boolean isCurrentArg(final Expression expr) {
176 return !stack.isEmpty() && stack.peek().contains(expr); //args to current apply call
177 }
178
179 private boolean isArguments(final Expression expr) {
180 if (expr instanceof IdentNode && ARGUMENTS.equals(((IdentNode)expr).getName())) {
181 argumentsFound.add(expr);
182 return true;
183 }
184 return false;
185 }
186
187 private boolean isParam(final String name) {
188 for (final IdentNode param : functionNode.getParameters()) {
189 if (param.getName().equals(name)) {
190 return true;
191 }
192 }
193 return false;
194 }
195
196 @Override
197 public Node leaveIdentNode(final IdentNode identNode) {
198 if (isParam(identNode.getName())) {
199 throw new TransformFailedException(lc.getCurrentFunction(), "parameter: " + identNode.getName());
200 }
201 // it's OK if 'argument' occurs as the current argument of an apply
202 if (isArguments(identNode) && !isCurrentArg(identNode)) {
203 throw new TransformFailedException(lc.getCurrentFunction(), "is 'arguments': " + identNode.getName());
204 }
205 return identNode;
206 }
207
208 @Override
209 public boolean enterCallNode(final CallNode callNode) {
210 final Set<Expression> callArgs = new HashSet<>();
211 if (isApply(callNode)) {
212 final List<Expression> argList = callNode.getArgs();
213 if (argList.size() != 2 || !isArguments(argList.get(argList.size() - 1))) {
214 throw new TransformFailedException(lc.getCurrentFunction(), "argument pattern not matched: " + argList);
215 }
216 callArgs.addAll(callNode.getArgs());
217 }
218 stack.push(callArgs);
219 return true;
220 }
221
222 @Override
223 public Node leaveCallNode(final CallNode callNode) {
224 stack.pop();
225 return callNode;
226 }
227 });
228 }
229
230 @Override
231 public boolean enterCallNode(final CallNode callNode) {
232 return !explodedArguments.isEmpty();
233 }
234
235 @Override
236 public Node leaveCallNode(final CallNode callNode) {
237 //apply needs to be a global symbol or we don't allow it
238
239 final List<IdentNode> newParams = explodedArguments.peek();
240 if (isApply(callNode)) {
241 final List<Expression> newArgs = new ArrayList<>();
242 for (final Expression arg : callNode.getArgs()) {
243 if (arg instanceof IdentNode && ARGUMENTS.equals(((IdentNode)arg).getName())) {
244 newArgs.addAll(newParams);
245 } else {
246 newArgs.add(arg);
247 }
248 }
249
250 changed.add(lc.getCurrentFunction().getId());
251
252 final CallNode newCallNode = callNode.setArgs(newArgs).setIsApplyToCall();
253
254 if (log.isEnabled()) {
255 log.fine("Transformed ",
256 callNode,
257 " from apply to call => ",
258 newCallNode,
259 " in ",
260 DebugLogger.quote(lc.getCurrentFunction().getName()));
261 }
262
263 return newCallNode;
264 }
265
266 return callNode;
267 }
268
269 private void pushExplodedArgs(final FunctionNode functionNode) {
270 int start = 0;
271
272 final MethodType actualCallSiteType = compiler.getCallSiteType(functionNode);
273 if (actualCallSiteType == null) {
274 throw new TransformFailedException(lc.getCurrentFunction(), "No callsite type");
275 }
276 assert actualCallSiteType.parameterType(actualCallSiteType.parameterCount() - 1) != Object[].class : "error vararg callsite passed to apply2call " + functionNode.getName() + " " + actualCallSiteType;
277
278 final TypeMap ptm = compiler.getTypeMap();
279 if (ptm.needsCallee()) {
280 start++;
281 }
282
283 start++; // we always use this
284
285 assert functionNode.getNumOfParams() == 0 : "apply2call on function with named paramaters!";
286 final List<IdentNode> newParams = new ArrayList<>();
287 final long to = actualCallSiteType.parameterCount() - start;
288 for (int i = 0; i < to; i++) {
289 newParams.add(new IdentNode(functionNode.getToken(), functionNode.getFinish(), EXPLODED_ARGUMENT_PREFIX.symbolName() + (i)));
290 }
291
292 callSiteTypes.push(actualCallSiteType);
293 explodedArguments.push(newParams);
294 }
295
296 @Override
297 public boolean enterFunctionNode(final FunctionNode functionNode) {
298 // Cheap tests first
299 if (!(
300 // is the transform globally enabled?
301 USE_APPLY2CALL
302
303 // Are we compiling lazily? We can't known the number and types of the actual parameters at
304 // the caller when compiling eagerly, so this only works with on-demand compilation.
305 && compiler.isOnDemandCompilation()
306
307 // Does the function even reference the "arguments" identifier (without redefining it)? If not,
308 // it trivially can't have an expression of form "f.apply(self, arguments)" that this transform
309 // is targeting.
310 && functionNode.needsArguments()
311
312 // Does the function have eval? If so, it can arbitrarily modify arguments so we can't touch it.
313 && !functionNode.hasEval()
314
315 // Finally, does the function declare any parameters explicitly? We don't support that. It could
316 // be done, but has some complications. Therefore only a function with no explicit parameters
317 // is considered.
318 && functionNode.getNumOfParams() == 0))
319 {
320 return false;
321 }
322
323 if (!Global.isBuiltinFunctionPrototypeApply()) {
324 log.fine("Apply transform disabled: apply/call overridden");
325 assert !Global.isBuiltinFunctionPrototypeCall() : "call and apply should have the same SwitchPoint";
326 return false;
327 }
328
329 if (!hasApplies(functionNode)) {
330 return false;
331 }
332
333 if (log.isEnabled()) {
334 log.info("Trying to specialize apply to call in '",
335 functionNode.getName(),
336 "' params=",
337 functionNode.getParameters(),
338 " id=",
339 functionNode.getId(),
340 " source=",
341 massageURL(functionNode.getSource().getURL()));
342 }
343
344 try {
345 checkValidTransform(functionNode);
346 pushExplodedArgs(functionNode);
347 } catch (final TransformFailedException e) {
348 log.info("Failure: ", e.getMessage());
349 return false;
350 }
351
352 return true;
353 }
354
355 /**
356 * Try to do the apply to call transformation
357 * @return true if successful, false otherwise
358 */
359 @Override
360 public Node leaveFunctionNode(final FunctionNode functionNode) {
361 FunctionNode newFunctionNode = functionNode;
362 final String functionName = newFunctionNode.getName();
363
364 if (changed.contains(newFunctionNode.getId())) {
365 newFunctionNode = newFunctionNode.clearFlag(lc, FunctionNode.USES_ARGUMENTS).
366 setFlag(lc, FunctionNode.HAS_APPLY_TO_CALL_SPECIALIZATION).
367 setParameters(lc, explodedArguments.peek());
368
369 if (log.isEnabled()) {
370 log.info("Success: ",
371 massageURL(newFunctionNode.getSource().getURL()),
372 '.',
373 functionName,
374 "' id=",
375 newFunctionNode.getId(),
376 " params=",
377 callSiteTypes.peek());
378 }
379 }
380
381 callSiteTypes.pop();
382 explodedArguments.pop();
383
384 return newFunctionNode;
385 }
386
387 private static boolean isApply(final CallNode callNode) {
388 final Expression f = callNode.getFunction();
389 return f instanceof AccessNode && "apply".equals(((AccessNode)f).getProperty());
390 }
391
392 private static String massageURL(final URL url) {
393 if (url == null) {
394 return "<null>";
395 }
396 final String str = url.toString();
397 final int slash = str.lastIndexOf('/');
398 if (slash == -1) {
399 return str;
400 }
401 return str.substring(slash + 1);
402 }
403 }