1 /* 2 * Copyright (c) 2010, 2013, 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.runtime; 27 28 import static jdk.nashorn.internal.lookup.Lookup.MH; 29 30 import java.lang.invoke.MethodHandle; 31 import java.lang.invoke.MethodHandles; 32 import java.lang.invoke.MethodType; 33 import java.util.ArrayList; 34 import java.util.Arrays; 35 import java.util.LinkedList; 36 import jdk.internal.dynalink.support.NameCodec; 37 38 import jdk.nashorn.internal.codegen.Compiler; 39 import jdk.nashorn.internal.codegen.CompilerConstants; 40 import jdk.nashorn.internal.codegen.FunctionSignature; 41 import jdk.nashorn.internal.codegen.types.Type; 42 import jdk.nashorn.internal.ir.FunctionNode; 43 import jdk.nashorn.internal.ir.FunctionNode.CompilationState; 44 import jdk.nashorn.internal.parser.Token; 45 import jdk.nashorn.internal.parser.TokenType; 46 47 /** 48 * This is a subclass that represents a script function that may be regenerated, 49 * for example with specialization based on call site types, or lazily generated. 50 * The common denominator is that it can get new invokers during its lifespan, 51 * unlike {@code FinalScriptFunctionData} 52 */ 53 public final class RecompilableScriptFunctionData extends ScriptFunctionData { 54 55 /** FunctionNode with the code for this ScriptFunction */ 56 private FunctionNode functionNode; 57 58 /** Source from which FunctionNode was parsed. */ 59 private final Source source; 60 61 /** Token of this function within the source. */ 62 private final long token; 63 64 /** Allocator map from makeMap() */ 65 private final PropertyMap allocatorMap; 66 67 /** Code installer used for all further recompilation/specialization of this ScriptFunction */ 68 private CodeInstaller<ScriptEnvironment> installer; 69 70 /** Name of class where allocator function resides */ 71 private final String allocatorClassName; 72 73 /** lazily generated allocator */ 74 private MethodHandle allocator; 75 76 private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup(); 77 78 /** 79 * Used for specialization based on runtime arguments. Whenever we specialize on 80 * callsite parameter types at runtime, we need to use a parameter type guard to 81 * ensure that the specialized version of the script function continues to be 82 * applicable for a particular callsite * 83 */ 84 private static final MethodHandle PARAM_TYPE_GUARD = findOwnMH("paramTypeGuard", boolean.class, Type[].class, Object[].class); 85 86 /** 87 * It is usually a good gamble whever we detect a runtime callsite with a double 88 * (or java.lang.Number instance) to specialize the parameter to an integer, if the 89 * parameter in question can be represented as one. The double typically only exists 90 * because the compiler doesn't know any better than "a number type" and conservatively 91 * picks doubles when it can't prove that an integer addition wouldn't overflow 92 */ 93 private static final MethodHandle ENSURE_INT = findOwnMH("ensureInt", int.class, Object.class); 94 95 /** 96 * Constructor - public as scripts use it 97 * 98 * @param functionNode functionNode that represents this function code 99 * @param installer installer for code regeneration versions of this function 100 * @param allocatorClassName name of our allocator class, will be looked up dynamically if used as a constructor 101 * @param allocatorMap allocator map to seed instances with, when constructing 102 */ 103 public RecompilableScriptFunctionData(final FunctionNode functionNode, final CodeInstaller<ScriptEnvironment> installer, final String allocatorClassName, final PropertyMap allocatorMap) { 104 super(functionName(functionNode), 105 functionNode.getParameters().size(), 106 functionNode.isStrict(), 107 false, 108 true); 109 110 this.functionNode = functionNode; 111 this.source = functionNode.getSource(); 112 this.token = tokenFor(functionNode); 113 this.installer = installer; 114 this.allocatorClassName = allocatorClassName; 115 this.allocatorMap = allocatorMap; 116 } 117 118 @Override 119 String toSource() { 120 if (source != null && token != 0) { 121 return source.getString(Token.descPosition(token), Token.descLength(token)); 122 } 123 124 return "function " + (name == null ? "" : name) + "() { [native code] }"; 125 } 126 127 @Override 128 public String toString() { 129 final StringBuilder sb = new StringBuilder(); 130 131 if (source != null) { 132 sb.append(source.getName()) 133 .append(':') 134 .append(functionNode.getLineNumber()) 135 .append(' '); 136 } 137 138 return sb.toString() + super.toString(); 139 } 140 141 private static String functionName(final FunctionNode fn) { 142 if (fn.isAnonymous()) { 143 return ""; 144 } else { 145 final FunctionNode.Kind kind = fn.getKind(); 146 if (kind == FunctionNode.Kind.GETTER || kind == FunctionNode.Kind.SETTER) { 147 final String name = NameCodec.decode(fn.getIdent().getName()); 148 return name.substring(4); // 4 is "get " or "set " 149 } else { 150 return fn.getIdent().getName(); 151 } 152 } 153 } 154 155 private static long tokenFor(final FunctionNode fn) { 156 final int position = Token.descPosition(fn.getFirstToken()); 157 final int length = Token.descPosition(fn.getLastToken()) - position + Token.descLength(fn.getLastToken()); 158 159 return Token.toDesc(TokenType.FUNCTION, position, length); 160 } 161 162 @Override 163 ScriptObject allocate(final PropertyMap map) { 164 try { 165 ensureHasAllocator(); //if allocatorClass name is set to null (e.g. for bound functions) we don't even try 166 return allocator == null ? null : (ScriptObject)allocator.invokeExact(map); 167 } catch (final RuntimeException | Error e) { 168 throw e; 169 } catch (final Throwable t) { 170 throw new RuntimeException(t); 171 } 172 } 173 174 private void ensureHasAllocator() throws ClassNotFoundException { 175 if (allocator == null && allocatorClassName != null) { 176 this.allocator = MH.findStatic(LOOKUP, Context.forStructureClass(allocatorClassName), CompilerConstants.ALLOCATE.symbolName(), MH.type(ScriptObject.class, PropertyMap.class)); 177 } 178 } 179 180 @Override 181 PropertyMap getAllocatorMap() { 182 return allocatorMap; 183 } 184 185 @Override 186 protected synchronized void ensureCodeGenerated() { 187 if (!code.isEmpty()) { 188 return; // nothing to do, we have code, at least some. 189 } 190 191 if (functionNode.isLazy()) { 192 Compiler.LOG.info("Trampoline hit: need to do lazy compilation of '", functionNode.getName(), "'"); 193 final Compiler compiler = new Compiler(installer); 194 functionNode = compiler.compile(functionNode); 195 assert !functionNode.isLazy(); 196 compiler.install(functionNode); 197 198 /* 199 * We don't need to update any flags - varArgs and needsCallee are instrincic 200 * in the function world we need to get a destination node from the compile instead 201 * and replace it with our function node. TODO 202 */ 203 } 204 205 /* 206 * We can't get to this program point unless we have bytecode, either from 207 * eager compilation or from running a lazy compile on the lines above 208 */ 209 210 assert functionNode.hasState(CompilationState.EMITTED) : functionNode.getName() + " " + functionNode.getState() + " " + Debug.id(functionNode); 211 212 // code exists - look it up and add it into the automatically sorted invoker list 213 addCode(functionNode); 214 215 if (! functionNode.canSpecialize()) { 216 // allow GC to claim IR stuff that is not needed anymore 217 functionNode = null; 218 installer = null; 219 } 220 } 221 222 private MethodHandle addCode(final FunctionNode fn) { 223 return addCode(fn, null, null, null); 224 } 225 226 private MethodHandle addCode(final FunctionNode fn, final MethodType runtimeType, final MethodHandle guard, final MethodHandle fallback) { 227 final MethodType targetType = new FunctionSignature(fn).getMethodType(); 228 MethodHandle target = 229 MH.findStatic( 230 LOOKUP, 231 fn.getCompileUnit().getCode(), 232 fn.getName(), 233 targetType); 234 235 /* 236 * For any integer argument. a double that is representable as an integer is OK. 237 * otherwise the guard would have failed. in that case introduce a filter that 238 * casts the double to an integer, which we know will preserve all precision. 239 */ 240 for (int i = 0; i < targetType.parameterCount(); i++) { 241 if (targetType.parameterType(i) == int.class) { 242 //representable as int 243 target = MH.filterArguments(target, i, ENSURE_INT); 244 } 245 } 246 247 MethodHandle mh = target; 248 if (guard != null) { 249 mh = MH.guardWithTest(MH.asCollector(guard, Object[].class, target.type().parameterCount()), MH.asType(target, fallback.type()), fallback); 250 } 251 252 final CompiledFunction cf = new CompiledFunction(runtimeType == null ? targetType : runtimeType, mh); 253 code.add(cf); 254 255 return cf.getInvoker(); 256 } 257 258 private static Type runtimeType(final Object arg) { 259 if (arg == null) { 260 return Type.OBJECT; 261 } 262 263 final Class<?> clazz = arg.getClass(); 264 assert !clazz.isPrimitive() : "always boxed"; 265 if (clazz == Double.class) { 266 return JSType.isRepresentableAsInt((double)arg) ? Type.INT : Type.NUMBER; 267 } else if (clazz == Integer.class) { 268 return Type.INT; 269 } else if (clazz == Long.class) { 270 return Type.LONG; 271 } else if (clazz == String.class) { 272 return Type.STRING; 273 } 274 return Type.OBJECT; 275 } 276 277 private static boolean canCoerce(final Object arg, final Type type) { 278 Type argType = runtimeType(arg); 279 if (Type.widest(argType, type) == type || arg == ScriptRuntime.UNDEFINED) { 280 return true; 281 } 282 System.err.println(arg + " does not fit in "+ argType + " " + type + " " + arg.getClass()); 283 new Throwable().printStackTrace(); 284 return false; 285 } 286 287 @SuppressWarnings("unused") 288 private static boolean paramTypeGuard(final Type[] paramTypes, final Object... args) { 289 final int length = args.length; 290 assert args.length >= paramTypes.length; 291 292 //i==start, skip the this, callee params etc 293 int start = args.length - paramTypes.length; 294 for (int i = start; i < args.length; i++) { 295 final Object arg = args[i]; 296 if (!canCoerce(arg, paramTypes[i - start])) { 297 return false; 298 } 299 } 300 return true; 301 } 302 303 @SuppressWarnings("unused") 304 private static int ensureInt(final Object arg) { 305 if (arg instanceof Number) { 306 return ((Number)arg).intValue(); 307 } else if (arg instanceof Undefined) { 308 return 0; 309 } 310 throw new AssertionError(arg); 311 } 312 313 /** 314 * Given the runtime callsite args, compute a method type that is equivalent to what 315 * was passed - this is typically a lot more specific that what the compiler has been 316 * able to deduce 317 * @param callSiteType callsite type for the compiled callsite target 318 * @param args runtime arguments to the compiled callsite target 319 * @return adjusted method type, narrowed as to conform to runtime callsite type instead 320 */ 321 private static MethodType runtimeType(final MethodType callSiteType, final Object[] args) { 322 if (args == null) { 323 //for example bound, or otherwise runtime arguments to callsite unavailable, then 324 //do not change the type 325 return callSiteType; 326 } 327 final Class<?>[] paramTypes = new Class<?>[callSiteType.parameterCount()]; 328 final int start = args.length - callSiteType.parameterCount(); 329 for (int i = start; i < args.length; i++) { 330 paramTypes[i - start] = runtimeType(args[i]).getTypeClass(); 331 } 332 return MH.type(callSiteType.returnType(), paramTypes); 333 } 334 335 private static ArrayList<Type> runtimeType(final MethodType mt) { 336 final ArrayList<Type> type = new ArrayList<>(); 337 for (int i = 0; i < mt.parameterCount(); i++) { 338 type.add(Type.typeFor(mt.parameterType(i))); 339 } 340 return type; 341 } 342 343 @Override 344 synchronized MethodHandle getBestInvoker(final MethodType callSiteType, final Object[] args) { 345 final MethodType runtimeType = runtimeType(callSiteType, args); 346 assert runtimeType.parameterCount() == callSiteType.parameterCount(); 347 348 final MethodHandle mh = super.getBestInvoker(runtimeType, args); 349 350 /* 351 * Not all functions can be specialized, for example, if we deemed memory 352 * footprint too large to store a parse snapshot, or if it is meaningless 353 * to do so, such as e.g. for runScript 354 */ 355 if (functionNode == null || !functionNode.canSpecialize()) { 356 return mh; 357 } 358 359 /* 360 * Check if best invoker is equally specific or more specific than runtime 361 * type. In that case, we don't need further specialization, but can use 362 * whatever we have already. We know that it will match callSiteType, or it 363 * would not have been returned from getBestInvoker 364 */ 365 if (!code.isLessSpecificThan(runtimeType)) { 366 return mh; 367 } 368 369 int i; 370 final FunctionNode snapshot = functionNode.getSnapshot(); 371 assert snapshot != null; 372 373 /* 374 * Create a list of the arg types that the compiler knows about 375 * typically, the runtime args are a lot more specific, and we should aggressively 376 * try to use those whenever possible 377 * We WILL try to make an aggressive guess as possible, and add guards if needed. 378 * For example, if the compiler can deduce that we have a number type, but the runtime 379 * passes and int, we might still want to keep it an int, and the gamble to 380 * check that whatever is passed is int representable usually pays off 381 * If the compiler only knows that a parameter is an "Object", it is still worth 382 * it to try to specialize it by looking at the runtime arg. 383 */ 384 final LinkedList<Type> compileTimeArgs = new LinkedList<>(); 385 for (i = callSiteType.parameterCount() - 1; i >= 0 && compileTimeArgs.size() < snapshot.getParameters().size(); i--) { 386 compileTimeArgs.addFirst(Type.typeFor(callSiteType.parameterType(i))); 387 } 388 389 /* 390 * The classes known at compile time are a safe to generate as primitives without parameter guards 391 * But the classes known at runtime (if more specific than compile time types) are safe to generate as primitives 392 * IFF there are parameter guards 393 */ 394 MethodHandle guard = null; 395 final ArrayList<Type> runtimeParamTypes = runtimeType(runtimeType); 396 while (runtimeParamTypes.size() > functionNode.getParameters().size()) { 397 runtimeParamTypes.remove(0); 398 } 399 for (i = 0; i < compileTimeArgs.size(); i++) { 400 final Type rparam = Type.typeFor(runtimeType.parameterType(i)); 401 final Type cparam = compileTimeArgs.get(i); 402 403 if (cparam.isObject() && !rparam.isObject()) { 404 //check that the runtime object is still coercible to the runtime type, because compiler can't prove it's always primitive 405 if (guard == null) { 406 guard = MH.insertArguments(PARAM_TYPE_GUARD, 0, (Object)runtimeParamTypes.toArray(new Type[runtimeParamTypes.size()])); 407 } 408 } 409 } 410 411 Compiler.LOG.info("Callsite specialized ", name, " runtimeType=", runtimeType, " parameters=", snapshot.getParameters(), " args=", Arrays.asList(args)); 412 413 assert snapshot != null; 414 assert snapshot != functionNode; 415 416 final Compiler compiler = new Compiler(installer); 417 418 final FunctionNode compiledSnapshot = compiler.compile( 419 snapshot.setHints( 420 null, 421 new Compiler.Hints(runtimeParamTypes.toArray(new Type[runtimeParamTypes.size()])))); 422 423 /* 424 * No matter how narrow your types were, they can never be narrower than Attr during recompile made them. I.e. you 425 * can put an int into the function here, if you see it as a runtime type, but if the function uses a multiplication 426 * on it, it will still need to be a double. At least until we have overflow checks. Similarly, if an int is 427 * passed but it is used as a string, it makes no sense to make the parameter narrower than Object. At least until 428 * the "different types for one symbol in difference places" work is done 429 */ 430 compiler.install(compiledSnapshot); 431 432 return addCode(compiledSnapshot, runtimeType, guard, mh); 433 } 434 435 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 436 return MH.findStatic(MethodHandles.lookup(), RecompilableScriptFunctionData.class, name, MH.type(rtype, types)); 437 } 438 439 } 440 --- EOF ---