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.codegen; 27 28 import static jdk.nashorn.internal.codegen.ClassEmitter.Flag.PRIVATE; 29 import static jdk.nashorn.internal.codegen.ClassEmitter.Flag.STATIC; 30 import static jdk.nashorn.internal.codegen.CompilerConstants.ARGUMENTS; 31 import static jdk.nashorn.internal.codegen.CompilerConstants.CALLEE; 32 import static jdk.nashorn.internal.codegen.CompilerConstants.CREATE_PROGRAM_FUNCTION; 33 import static jdk.nashorn.internal.codegen.CompilerConstants.GET_MAP; 34 import static jdk.nashorn.internal.codegen.CompilerConstants.GET_STRING; 35 import static jdk.nashorn.internal.codegen.CompilerConstants.QUICK_PREFIX; 36 import static jdk.nashorn.internal.codegen.CompilerConstants.REGEX_PREFIX; 37 import static jdk.nashorn.internal.codegen.CompilerConstants.RETURN; 38 import static jdk.nashorn.internal.codegen.CompilerConstants.SCOPE; 39 import static jdk.nashorn.internal.codegen.CompilerConstants.SPLIT_ARRAY_ARG; 40 import static jdk.nashorn.internal.codegen.CompilerConstants.SPLIT_PREFIX; 41 import static jdk.nashorn.internal.codegen.CompilerConstants.THIS; 42 import static jdk.nashorn.internal.codegen.CompilerConstants.VARARGS; 43 import static jdk.nashorn.internal.codegen.CompilerConstants.constructorNoLookup; 44 import static jdk.nashorn.internal.codegen.CompilerConstants.interfaceCallNoLookup; 45 import static jdk.nashorn.internal.codegen.CompilerConstants.methodDescriptor; 46 import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup; 47 import static jdk.nashorn.internal.codegen.CompilerConstants.typeDescriptor; 48 import static jdk.nashorn.internal.codegen.CompilerConstants.virtualCallNoLookup; 49 import static jdk.nashorn.internal.codegen.ObjectClassGenerator.OBJECT_FIELDS_ONLY; 50 import static jdk.nashorn.internal.ir.Symbol.HAS_SLOT; 51 import static jdk.nashorn.internal.ir.Symbol.IS_INTERNAL; 52 import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.INVALID_PROGRAM_POINT; 53 import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.isValid; 54 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_APPLY_TO_CALL; 55 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_FAST_SCOPE; 56 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_OPTIMISTIC; 57 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_PROGRAM_POINT_SHIFT; 58 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_SCOPE; 59 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_STRICT; 60 61 import java.io.PrintWriter; 62 import java.util.ArrayDeque; 63 import java.util.ArrayList; 64 import java.util.Arrays; 65 import java.util.BitSet; 66 import java.util.Collection; 67 import java.util.Collections; 68 import java.util.Deque; 69 import java.util.EnumSet; 70 import java.util.HashMap; 71 import java.util.HashSet; 72 import java.util.Iterator; 73 import java.util.LinkedList; 74 import java.util.List; 75 import java.util.Map; 76 import java.util.Set; 77 import java.util.TreeMap; 78 import java.util.function.Supplier; 79 import jdk.nashorn.internal.IntDeque; 80 import jdk.nashorn.internal.codegen.ClassEmitter.Flag; 81 import jdk.nashorn.internal.codegen.CompilerConstants.Call; 82 import jdk.nashorn.internal.codegen.types.ArrayType; 83 import jdk.nashorn.internal.codegen.types.Type; 84 import jdk.nashorn.internal.ir.AccessNode; 85 import jdk.nashorn.internal.ir.BaseNode; 86 import jdk.nashorn.internal.ir.BinaryNode; 87 import jdk.nashorn.internal.ir.Block; 88 import jdk.nashorn.internal.ir.BlockStatement; 89 import jdk.nashorn.internal.ir.BreakNode; 90 import jdk.nashorn.internal.ir.BreakableNode; 91 import jdk.nashorn.internal.ir.CallNode; 92 import jdk.nashorn.internal.ir.CaseNode; 93 import jdk.nashorn.internal.ir.CatchNode; 94 import jdk.nashorn.internal.ir.ContinueNode; 95 import jdk.nashorn.internal.ir.EmptyNode; 96 import jdk.nashorn.internal.ir.Expression; 97 import jdk.nashorn.internal.ir.ExpressionStatement; 98 import jdk.nashorn.internal.ir.ForNode; 99 import jdk.nashorn.internal.ir.FunctionNode; 100 import jdk.nashorn.internal.ir.FunctionNode.CompilationState; 101 import jdk.nashorn.internal.ir.IdentNode; 102 import jdk.nashorn.internal.ir.IfNode; 103 import jdk.nashorn.internal.ir.IndexNode; 104 import jdk.nashorn.internal.ir.JoinPredecessor; 105 import jdk.nashorn.internal.ir.JoinPredecessorExpression; 106 import jdk.nashorn.internal.ir.LabelNode; 107 import jdk.nashorn.internal.ir.LexicalContext; 108 import jdk.nashorn.internal.ir.LexicalContextNode; 109 import jdk.nashorn.internal.ir.LiteralNode; 110 import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode; 111 import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode.ArrayUnit; 112 import jdk.nashorn.internal.ir.LiteralNode.PrimitiveLiteralNode; 113 import jdk.nashorn.internal.ir.LocalVariableConversion; 114 import jdk.nashorn.internal.ir.LoopNode; 115 import jdk.nashorn.internal.ir.Node; 116 import jdk.nashorn.internal.ir.ObjectNode; 117 import jdk.nashorn.internal.ir.Optimistic; 118 import jdk.nashorn.internal.ir.PropertyNode; 119 import jdk.nashorn.internal.ir.ReturnNode; 120 import jdk.nashorn.internal.ir.RuntimeNode; 121 import jdk.nashorn.internal.ir.RuntimeNode.Request; 122 import jdk.nashorn.internal.ir.SplitNode; 123 import jdk.nashorn.internal.ir.Statement; 124 import jdk.nashorn.internal.ir.SwitchNode; 125 import jdk.nashorn.internal.ir.Symbol; 126 import jdk.nashorn.internal.ir.TernaryNode; 127 import jdk.nashorn.internal.ir.ThrowNode; 128 import jdk.nashorn.internal.ir.TryNode; 129 import jdk.nashorn.internal.ir.UnaryNode; 130 import jdk.nashorn.internal.ir.VarNode; 131 import jdk.nashorn.internal.ir.WhileNode; 132 import jdk.nashorn.internal.ir.WithNode; 133 import jdk.nashorn.internal.ir.visitor.NodeOperatorVisitor; 134 import jdk.nashorn.internal.ir.visitor.NodeVisitor; 135 import jdk.nashorn.internal.objects.Global; 136 import jdk.nashorn.internal.objects.ScriptFunctionImpl; 137 import jdk.nashorn.internal.parser.Lexer.RegexToken; 138 import jdk.nashorn.internal.parser.TokenType; 139 import jdk.nashorn.internal.runtime.Context; 140 import jdk.nashorn.internal.runtime.Debug; 141 import jdk.nashorn.internal.runtime.ECMAException; 142 import jdk.nashorn.internal.runtime.JSType; 143 import jdk.nashorn.internal.runtime.OptimisticReturnFilters; 144 import jdk.nashorn.internal.runtime.PropertyMap; 145 import jdk.nashorn.internal.runtime.RecompilableScriptFunctionData; 146 import jdk.nashorn.internal.runtime.RewriteException; 147 import jdk.nashorn.internal.runtime.Scope; 148 import jdk.nashorn.internal.runtime.ScriptEnvironment; 149 import jdk.nashorn.internal.runtime.ScriptFunction; 150 import jdk.nashorn.internal.runtime.ScriptObject; 151 import jdk.nashorn.internal.runtime.ScriptRuntime; 152 import jdk.nashorn.internal.runtime.Source; 153 import jdk.nashorn.internal.runtime.Undefined; 154 import jdk.nashorn.internal.runtime.UnwarrantedOptimismException; 155 import jdk.nashorn.internal.runtime.arrays.ArrayData; 156 import jdk.nashorn.internal.runtime.linker.LinkerCallSite; 157 import jdk.nashorn.internal.runtime.logging.DebugLogger; 158 import jdk.nashorn.internal.runtime.logging.Loggable; 159 import jdk.nashorn.internal.runtime.logging.Logger; 160 import jdk.nashorn.internal.runtime.options.Options; 161 162 /** 163 * This is the lowest tier of the code generator. It takes lowered ASTs emitted 164 * from Lower and emits Java byte code. The byte code emission logic is broken 165 * out into MethodEmitter. MethodEmitter works internally with a type stack, and 166 * keeps track of the contents of the byte code stack. This way we avoid a large 167 * number of special cases on the form 168 * <pre> 169 * if (type == INT) { 170 * visitInsn(ILOAD, slot); 171 * } else if (type == DOUBLE) { 172 * visitInsn(DOUBLE, slot); 173 * } 174 * </pre> 175 * This quickly became apparent when the code generator was generalized to work 176 * with all types, and not just numbers or objects. 177 * <p> 178 * The CodeGenerator visits nodes only once, tags them as resolved and emits 179 * bytecode for them. 180 */ 181 @Logger(name="codegen") 182 final class CodeGenerator extends NodeOperatorVisitor<CodeGeneratorLexicalContext> implements Loggable { 183 184 private static final Type SCOPE_TYPE = Type.typeFor(ScriptObject.class); 185 186 private static final String GLOBAL_OBJECT = Type.getInternalName(Global.class); 187 188 private static final String SCRIPTFUNCTION_IMPL_NAME = Type.getInternalName(ScriptFunctionImpl.class); 189 private static final Type SCRIPTFUNCTION_IMPL_TYPE = Type.typeFor(ScriptFunction.class); 190 191 private static final Call CREATE_REWRITE_EXCEPTION = CompilerConstants.staticCallNoLookup(RewriteException.class, 192 "create", RewriteException.class, UnwarrantedOptimismException.class, Object[].class, String[].class); 193 private static final Call CREATE_REWRITE_EXCEPTION_REST_OF = CompilerConstants.staticCallNoLookup(RewriteException.class, 194 "create", RewriteException.class, UnwarrantedOptimismException.class, Object[].class, String[].class, int[].class); 195 196 private static final Call ENSURE_INT = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class, 197 "ensureInt", int.class, Object.class, int.class); 198 private static final Call ENSURE_LONG = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class, 199 "ensureLong", long.class, Object.class, int.class); 200 private static final Call ENSURE_NUMBER = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class, 201 "ensureNumber", double.class, Object.class, int.class); 202 203 private static final Class<?> ITERATOR_CLASS = Iterator.class; 204 static { 205 assert ITERATOR_CLASS == CompilerConstants.ITERATOR_PREFIX.type(); 206 } 207 private static final Type ITERATOR_TYPE = Type.typeFor(ITERATOR_CLASS); 208 private static final Type EXCEPTION_TYPE = Type.typeFor(CompilerConstants.EXCEPTION_PREFIX.type()); 209 210 /** Constant data & installation. The only reason the compiler keeps this is because it is assigned 211 * by reflection in class installation */ 212 private final Compiler compiler; 213 214 /** Is the current code submitted by 'eval' call? */ 215 private final boolean evalCode; 216 217 /** Call site flags given to the code generator to be used for all generated call sites */ 218 private final int callSiteFlags; 219 220 /** How many regexp fields have been emitted */ 221 private int regexFieldCount; 222 223 /** Line number for last statement. If we encounter a new line number, line number bytecode information 224 * needs to be generated */ 225 private int lastLineNumber = -1; 226 227 /** When should we stop caching regexp expressions in fields to limit bytecode size? */ 228 private static final int MAX_REGEX_FIELDS = 2 * 1024; 229 230 /** Current method emitter */ 231 private MethodEmitter method; 232 233 /** Current compile unit */ 234 private CompileUnit unit; 235 236 private final DebugLogger log; 237 238 /** From what size should we use spill instead of fields for JavaScript objects? */ 239 private static final int OBJECT_SPILL_THRESHOLD = Options.getIntProperty("nashorn.spill.threshold", 256); 240 241 private static boolean assertsEnabled = false; 242 static { 243 assert assertsEnabled = true; // Intentional side effect 244 } 245 246 private final Set<String> emittedMethods = new HashSet<>(); 247 248 // Function Id -> ContinuationInfo. Used by compilation of rest-of function only. 249 private final Map<Integer, ContinuationInfo> fnIdToContinuationInfo = new HashMap<>(); 250 251 private final Deque<Label> scopeEntryLabels = new ArrayDeque<>(); 252 253 private final Set<Integer> initializedFunctionIds = new HashSet<>(); 254 255 private static final Label METHOD_BOUNDARY = new Label(""); 256 private final Deque<Label> catchLabels = new ArrayDeque<>(); 257 // Number of live locals on entry to (and thus also break from) labeled blocks. 258 private final IntDeque labeledBlockBreakLiveLocals = new IntDeque(); 259 260 //is this a rest of compilation 261 private final int[] continuationEntryPoints; 262 263 /** 264 * Constructor. 265 * 266 * @param compiler 267 */ 268 CodeGenerator(final Compiler compiler, final int[] continuationEntryPoints) { 269 super(new CodeGeneratorLexicalContext()); 270 this.compiler = compiler; 271 this.evalCode = compiler.getSource().isEvalCode(); 272 this.continuationEntryPoints = continuationEntryPoints; 273 this.callSiteFlags = compiler.getScriptEnvironment()._callsite_flags; 274 this.log = initLogger(compiler.getContext()); 275 } 276 277 @Override 278 public DebugLogger getLogger() { 279 return log; 280 } 281 282 @Override 283 public DebugLogger initLogger(final Context context) { 284 return context.getLogger(this.getClass()); 285 } 286 287 /** 288 * Gets the call site flags, adding the strict flag if the current function 289 * being generated is in strict mode 290 * 291 * @return the correct flags for a call site in the current function 292 */ 293 int getCallSiteFlags() { 294 return lc.getCurrentFunction().isStrict() ? callSiteFlags | CALLSITE_STRICT : callSiteFlags; 295 } 296 297 /** 298 * Are we generating code for 'eval' code? 299 * @return true if currently compiled code is 'eval' code. 300 */ 301 boolean isEvalCode() { 302 return evalCode; 303 } 304 305 /** 306 * Load an identity node 307 * 308 * @param identNode an identity node to load 309 * @return the method generator used 310 */ 311 private MethodEmitter loadIdent(final IdentNode identNode, final TypeBounds resultBounds) { 312 final Symbol symbol = identNode.getSymbol(); 313 314 if (!symbol.isScope()) { 315 final Type type = identNode.getType(); 316 if(type == Type.UNDEFINED) { 317 return method.loadUndefined(Type.OBJECT); 318 } 319 320 assert symbol.hasSlot() || symbol.isParam(); 321 return method.load(identNode); 322 } 323 324 assert identNode.getSymbol().isScope() : identNode + " is not in scope!"; 325 final int flags = CALLSITE_SCOPE | getCallSiteFlags(); 326 if (isFastScope(symbol)) { 327 // Only generate shared scope getter for fast-scope symbols so we know we can dial in correct scope. 328 if (symbol.getUseCount() > SharedScopeCall.FAST_SCOPE_GET_THRESHOLD && !isOptimisticOrRestOf()) { 329 method.loadCompilerConstant(SCOPE); 330 // As shared scope vars are only used in non-optimistic compilation, we switch from using TypeBounds to 331 // just a single definitive type, resultBounds.widest. 332 loadSharedScopeVar(resultBounds.widest, symbol, flags); 333 } else { 334 new LoadFastScopeVar(identNode, resultBounds, flags).emit(); 335 } 336 } else { 337 //slow scope load, we have no proto depth 338 new LoadScopeVar(identNode, resultBounds, flags).emit(); 339 } 340 341 return method; 342 } 343 344 private boolean isRestOf() { 345 return continuationEntryPoints != null; 346 } 347 348 private boolean isOptimisticOrRestOf() { 349 return useOptimisticTypes() || isRestOf(); 350 } 351 352 private boolean isCurrentContinuationEntryPoint(final int programPoint) { 353 return isRestOf() && getCurrentContinuationEntryPoint() == programPoint; 354 } 355 356 private int[] getContinuationEntryPoints() { 357 return isRestOf() ? continuationEntryPoints : null; 358 } 359 360 private int getCurrentContinuationEntryPoint() { 361 return isRestOf() ? continuationEntryPoints[0] : INVALID_PROGRAM_POINT; 362 } 363 364 private boolean isContinuationEntryPoint(final int programPoint) { 365 if (isRestOf()) { 366 assert continuationEntryPoints != null; 367 for (final int cep : continuationEntryPoints) { 368 if (cep == programPoint) { 369 return true; 370 } 371 } 372 } 373 return false; 374 } 375 376 /** 377 * Check if this symbol can be accessed directly with a putfield or getfield or dynamic load 378 * 379 * @param symbol symbol to check for fast scope 380 * @return true if fast scope 381 */ 382 private boolean isFastScope(final Symbol symbol) { 383 if (!symbol.isScope()) { 384 return false; 385 } 386 387 if (!lc.inDynamicScope()) { 388 // If there's no with or eval in context, and the symbol is marked as scoped, it is fast scoped. Such a 389 // symbol must either be global, or its defining block must need scope. 390 assert symbol.isGlobal() || lc.getDefiningBlock(symbol).needsScope() : symbol.getName(); 391 return true; 392 } 393 394 if (symbol.isGlobal()) { 395 // Shortcut: if there's a with or eval in context, globals can't be fast scoped 396 return false; 397 } 398 399 // Otherwise, check if there's a dynamic scope between use of the symbol and its definition 400 final String name = symbol.getName(); 401 boolean previousWasBlock = false; 402 for (final Iterator<LexicalContextNode> it = lc.getAllNodes(); it.hasNext();) { 403 final LexicalContextNode node = it.next(); 404 if (node instanceof Block) { 405 // If this block defines the symbol, then we can fast scope the symbol. 406 final Block block = (Block)node; 407 if (block.getExistingSymbol(name) == symbol) { 408 assert block.needsScope(); 409 return true; 410 } 411 previousWasBlock = true; 412 } else { 413 if (node instanceof WithNode && previousWasBlock || node instanceof FunctionNode && ((FunctionNode)node).needsDynamicScope()) { 414 // If we hit a scope that can have symbols introduced into it at run time before finding the defining 415 // block, the symbol can't be fast scoped. A WithNode only counts if we've immediately seen a block 416 // before - its block. Otherwise, we are currently processing the WithNode's expression, and that's 417 // obviously not subjected to introducing new symbols. 418 return false; 419 } 420 previousWasBlock = false; 421 } 422 } 423 // Should've found the symbol defined in a block 424 throw new AssertionError(); 425 } 426 427 private MethodEmitter loadSharedScopeVar(final Type valueType, final Symbol symbol, final int flags) { 428 assert !isOptimisticOrRestOf(); 429 if (isFastScope(symbol)) { 430 method.load(getScopeProtoDepth(lc.getCurrentBlock(), symbol)); 431 } else { 432 method.load(-1); 433 } 434 return lc.getScopeGet(unit, symbol, valueType, flags | CALLSITE_FAST_SCOPE).generateInvoke(method); 435 } 436 437 private class LoadScopeVar extends OptimisticOperation { 438 final IdentNode identNode; 439 private final int flags; 440 441 LoadScopeVar(final IdentNode identNode, final TypeBounds resultBounds, final int flags) { 442 super(identNode, resultBounds); 443 this.identNode = identNode; 444 this.flags = flags; 445 } 446 447 @Override 448 void loadStack() { 449 method.loadCompilerConstant(SCOPE); 450 getProto(); 451 } 452 453 void getProto() { 454 //empty 455 } 456 457 @Override 458 void consumeStack() { 459 // If this is either __FILE__, __DIR__, or __LINE__ then load the property initially as Object as we'd convert 460 // it anyway for replaceLocationPropertyPlaceholder. 461 if(identNode.isCompileTimePropertyName()) { 462 method.dynamicGet(Type.OBJECT, identNode.getSymbol().getName(), flags, identNode.isFunction()); 463 replaceCompileTimeProperty(); 464 } else { 465 dynamicGet(identNode.getSymbol().getName(), flags, identNode.isFunction()); 466 } 467 } 468 } 469 470 private class LoadFastScopeVar extends LoadScopeVar { 471 LoadFastScopeVar(final IdentNode identNode, final TypeBounds resultBounds, final int flags) { 472 super(identNode, resultBounds, flags | CALLSITE_FAST_SCOPE); 473 } 474 475 @Override 476 void getProto() { 477 loadFastScopeProto(identNode.getSymbol(), false); 478 } 479 } 480 481 private MethodEmitter storeFastScopeVar(final Symbol symbol, final int flags) { 482 loadFastScopeProto(symbol, true); 483 method.dynamicSet(symbol.getName(), flags | CALLSITE_FAST_SCOPE); 484 return method; 485 } 486 487 private int getScopeProtoDepth(final Block startingBlock, final Symbol symbol) { 488 //walk up the chain from starting block and when we bump into the current function boundary, add the external 489 //information. 490 final FunctionNode fn = lc.getCurrentFunction(); 491 final int fnId = fn.getId(); 492 final int externalDepth = compiler.getScriptFunctionData(fnId).getExternalSymbolDepth(symbol.getName()); 493 494 //count the number of scopes from this place to the start of the function 495 496 final int internalDepth = FindScopeDepths.findInternalDepth(lc, fn, startingBlock, symbol); 497 final int scopesToStart = FindScopeDepths.findScopesToStart(lc, fn, startingBlock); 498 int depth = 0; 499 if (internalDepth == -1) { 500 depth = scopesToStart + externalDepth; 501 } else { 502 assert internalDepth <= scopesToStart; 503 depth = internalDepth; 504 } 505 506 return depth; 507 } 508 509 private void loadFastScopeProto(final Symbol symbol, final boolean swap) { 510 final int depth = getScopeProtoDepth(lc.getCurrentBlock(), symbol); 511 assert depth != -1 : "Couldn't find scope depth for symbol " + symbol.getName() + " in " + lc.getCurrentFunction(); 512 if (depth > 0) { 513 if (swap) { 514 method.swap(); 515 } 516 for (int i = 0; i < depth; i++) { 517 method.invoke(ScriptObject.GET_PROTO); 518 } 519 if (swap) { 520 method.swap(); 521 } 522 } 523 } 524 525 /** 526 * Generate code that loads this node to the stack, not constraining its type 527 * 528 * @param expr node to load 529 * 530 * @return the method emitter used 531 */ 532 private MethodEmitter loadExpressionUnbounded(final Expression expr) { 533 return loadExpression(expr, TypeBounds.UNBOUNDED); 534 } 535 536 private MethodEmitter loadExpressionAsObject(final Expression expr) { 537 return loadExpression(expr, TypeBounds.OBJECT); 538 } 539 540 MethodEmitter loadExpressionAsBoolean(final Expression expr) { 541 return loadExpression(expr, TypeBounds.BOOLEAN); 542 } 543 544 // Test whether conversion from source to target involves a call of ES 9.1 ToPrimitive 545 // with possible side effects from calling an object's toString or valueOf methods. 546 private static boolean noToPrimitiveConversion(final Type source, final Type target) { 547 // Object to boolean conversion does not cause ToPrimitive call 548 return source.isJSPrimitive() || !target.isJSPrimitive() || target.isBoolean(); 549 } 550 551 MethodEmitter loadBinaryOperands(final BinaryNode binaryNode) { 552 return loadBinaryOperands(binaryNode.lhs(), binaryNode.rhs(), TypeBounds.UNBOUNDED.notWiderThan(binaryNode.getWidestOperandType()), false); 553 } 554 555 private MethodEmitter loadBinaryOperands(final Expression lhs, final Expression rhs, final TypeBounds explicitOperandBounds, final boolean baseAlreadyOnStack) { 556 // ECMAScript 5.1 specification (sections 11.5-11.11 and 11.13) prescribes that when evaluating a binary 557 // expression "LEFT op RIGHT", the order of operations must be: LOAD LEFT, LOAD RIGHT, CONVERT LEFT, CONVERT 558 // RIGHT, EXECUTE OP. Unfortunately, doing it in this order defeats potential optimizations that arise when we 559 // can combine a LOAD with a CONVERT operation (e.g. use a dynamic getter with the conversion target type as its 560 // return value). What we do here is reorder LOAD RIGHT and CONVERT LEFT when possible; it is possible only when 561 // we can prove that executing CONVERT LEFT can't have a side effect that changes the value of LOAD RIGHT. 562 // Basically, if we know that either LEFT already is a primitive value, or does not have to be converted to 563 // a primitive value, or RIGHT is an expression that loads without side effects, then we can do the 564 // reordering and collapse LOAD/CONVERT into a single operation; otherwise we need to do the more costly 565 // separate operations to preserve specification semantics. 566 567 // Operands' load type should not be narrower than the narrowest of the individual operand types, nor narrower 568 // than the lower explicit bound, but it should also not be wider than 569 final Type narrowestOperandType = Type.narrowest(Type.widest(lhs.getType(), rhs.getType()), explicitOperandBounds.widest); 570 final TypeBounds operandBounds = explicitOperandBounds.notNarrowerThan(narrowestOperandType); 571 if (noToPrimitiveConversion(lhs.getType(), explicitOperandBounds.widest) || rhs.isLocal()) { 572 // Can reorder. Combine load and convert into single operations. 573 loadExpression(lhs, operandBounds, baseAlreadyOnStack); 574 loadExpression(rhs, operandBounds, false); 575 } else { 576 // Can't reorder. Load and convert separately. 577 final TypeBounds safeConvertBounds = TypeBounds.UNBOUNDED.notNarrowerThan(narrowestOperandType); 578 loadExpression(lhs, safeConvertBounds, baseAlreadyOnStack); 579 loadExpression(rhs, safeConvertBounds, false); 580 method.swap().convert(operandBounds.within(method.peekType())).swap().convert(operandBounds.within(method.peekType())); 581 } 582 assert Type.generic(method.peekType()) == operandBounds.narrowest; 583 assert Type.generic(method.peekType(1)) == operandBounds.narrowest; 584 585 return method; 586 } 587 588 private static final class TypeBounds { 589 final Type narrowest; 590 final Type widest; 591 592 static final TypeBounds UNBOUNDED = new TypeBounds(Type.UNKNOWN, Type.OBJECT); 593 static final TypeBounds INT = exact(Type.INT); 594 static final TypeBounds NUMBER = exact(Type.NUMBER); 595 static final TypeBounds OBJECT = exact(Type.OBJECT); 596 static final TypeBounds BOOLEAN = exact(Type.BOOLEAN); 597 598 static TypeBounds exact(final Type type) { 599 return new TypeBounds(type, type); 600 } 601 602 TypeBounds(final Type narrowest, final Type widest) { 603 assert widest != null && widest != Type.UNDEFINED && widest != Type.UNKNOWN : widest; 604 assert narrowest != null && narrowest != Type.UNDEFINED : narrowest; 605 assert !narrowest.widerThan(widest) : narrowest + " wider than " + widest; 606 assert !widest.narrowerThan(narrowest); 607 this.narrowest = Type.generic(narrowest); 608 this.widest = Type.generic(widest); 609 } 610 611 TypeBounds notNarrowerThan(final Type type) { 612 return maybeNew(Type.narrowest(Type.widest(narrowest, type), widest), widest); 613 } 614 615 TypeBounds notWiderThan(final Type type) { 616 return maybeNew(Type.narrowest(narrowest, type), Type.narrowest(widest, type)); 617 } 618 619 boolean canBeNarrowerThan(final Type type) { 620 return narrowest.narrowerThan(type); 621 } 622 623 TypeBounds maybeNew(final Type newNarrowest, final Type newWidest) { 624 if(newNarrowest == narrowest && newWidest == widest) { 625 return this; 626 } 627 return new TypeBounds(newNarrowest, newWidest); 628 } 629 630 TypeBounds booleanToInt() { 631 return maybeNew(booleanToInt(narrowest), booleanToInt(widest)); 632 } 633 634 TypeBounds objectToNumber() { 635 return maybeNew(objectToNumber(narrowest), objectToNumber(widest)); 636 } 637 638 private static Type booleanToInt(final Type t) { 639 return t == Type.BOOLEAN ? Type.INT : t; 640 } 641 642 private static Type objectToNumber(final Type t) { 643 return t.isObject() ? Type.NUMBER : t; 644 } 645 646 Type within(final Type type) { 647 if(type.narrowerThan(narrowest)) { 648 return narrowest; 649 } 650 if(type.widerThan(widest)) { 651 return widest; 652 } 653 return type; 654 } 655 656 @Override 657 public String toString() { 658 return "[" + narrowest + ", " + widest + "]"; 659 } 660 } 661 662 MethodEmitter loadExpressionAsType(final Expression expr, final Type type) { 663 if(type == Type.BOOLEAN) { 664 return loadExpressionAsBoolean(expr); 665 } else if(type == Type.UNDEFINED) { 666 assert expr.getType() == Type.UNDEFINED; 667 return loadExpressionAsObject(expr); 668 } 669 // having no upper bound preserves semantics of optimistic operations in the expression (by not having them 670 // converted early) and then applies explicit conversion afterwards. 671 return loadExpression(expr, TypeBounds.UNBOUNDED.notNarrowerThan(type)).convert(type); 672 } 673 674 private MethodEmitter loadExpression(final Expression expr, final TypeBounds resultBounds) { 675 return loadExpression(expr, resultBounds, false); 676 } 677 678 /** 679 * Emits code for evaluating an expression and leaving its value on top of the stack, narrowing or widening it if 680 * necessary. 681 * @param expr the expression to load 682 * @param resultBounds the incoming type bounds. The value on the top of the stack is guaranteed to not be of narrower 683 * type than the narrowest bound, or wider type than the widest bound after it is loaded. 684 * @param baseAlreadyOnStack true if the base of an access or index node is already on the stack. Used to avoid 685 * double evaluation of bases in self-assignment expressions to access and index nodes. {@code Type.OBJECT} is used 686 * to indicate the widest possible type. 687 * @return the method emitter 688 */ 689 private MethodEmitter loadExpression(final Expression expr, final TypeBounds resultBounds, final boolean baseAlreadyOnStack) { 690 691 /* 692 * The load may be of type IdentNode, e.g. "x", AccessNode, e.g. "x.y" 693 * or IndexNode e.g. "x[y]". Both AccessNodes and IndexNodes are 694 * BaseNodes and the logic for loading the base object is reused 695 */ 696 final CodeGenerator codegen = this; 697 698 final Node currentDiscard = codegen.lc.getCurrentDiscard(); 699 expr.accept(new NodeOperatorVisitor<LexicalContext>(new LexicalContext()) { 700 @Override 701 public boolean enterIdentNode(final IdentNode identNode) { 702 loadIdent(identNode, resultBounds); 703 return false; 704 } 705 706 @Override 707 public boolean enterAccessNode(final AccessNode accessNode) { 708 new OptimisticOperation(accessNode, resultBounds) { 709 @Override 710 void loadStack() { 711 if (!baseAlreadyOnStack) { 712 loadExpressionAsObject(accessNode.getBase()); 713 } 714 assert method.peekType().isObject(); 715 } 716 @Override 717 void consumeStack() { 718 final int flags = getCallSiteFlags(); 719 dynamicGet(accessNode.getProperty(), flags, accessNode.isFunction()); 720 } 721 }.emit(baseAlreadyOnStack ? 1 : 0); 722 return false; 723 } 724 725 @Override 726 public boolean enterIndexNode(final IndexNode indexNode) { 727 new OptimisticOperation(indexNode, resultBounds) { 728 @Override 729 void loadStack() { 730 if (!baseAlreadyOnStack) { 731 loadExpressionAsObject(indexNode.getBase()); 732 loadExpressionUnbounded(indexNode.getIndex()); 733 } 734 } 735 @Override 736 void consumeStack() { 737 final int flags = getCallSiteFlags(); 738 dynamicGetIndex(flags, indexNode.isFunction()); 739 } 740 }.emit(baseAlreadyOnStack ? 2 : 0); 741 return false; 742 } 743 744 @Override 745 public boolean enterFunctionNode(final FunctionNode functionNode) { 746 // function nodes will always leave a constructed function object on stack, no need to load the symbol 747 // separately as in enterDefault() 748 lc.pop(functionNode); 749 functionNode.accept(codegen); 750 // NOTE: functionNode.accept() will produce a different FunctionNode that we discard. This incidentally 751 // doesn't cause problems as we're never touching FunctionNode again after it's visited here - codegen 752 // is the last element in the compilation pipeline, the AST it produces is not used externally. So, we 753 // re-push the original functionNode. 754 lc.push(functionNode); 755 return false; 756 } 757 758 @Override 759 public boolean enterASSIGN(final BinaryNode binaryNode) { 760 loadASSIGN(binaryNode); 761 return false; 762 } 763 764 @Override 765 public boolean enterASSIGN_ADD(final BinaryNode binaryNode) { 766 loadASSIGN_ADD(binaryNode); 767 return false; 768 } 769 770 @Override 771 public boolean enterASSIGN_BIT_AND(final BinaryNode binaryNode) { 772 loadASSIGN_BIT_AND(binaryNode); 773 return false; 774 } 775 776 @Override 777 public boolean enterASSIGN_BIT_OR(final BinaryNode binaryNode) { 778 loadASSIGN_BIT_OR(binaryNode); 779 return false; 780 } 781 782 @Override 783 public boolean enterASSIGN_BIT_XOR(final BinaryNode binaryNode) { 784 loadASSIGN_BIT_XOR(binaryNode); 785 return false; 786 } 787 788 @Override 789 public boolean enterASSIGN_DIV(final BinaryNode binaryNode) { 790 loadASSIGN_DIV(binaryNode); 791 return false; 792 } 793 794 @Override 795 public boolean enterASSIGN_MOD(final BinaryNode binaryNode) { 796 loadASSIGN_MOD(binaryNode); 797 return false; 798 } 799 800 @Override 801 public boolean enterASSIGN_MUL(final BinaryNode binaryNode) { 802 loadASSIGN_MUL(binaryNode); 803 return false; 804 } 805 806 @Override 807 public boolean enterASSIGN_SAR(final BinaryNode binaryNode) { 808 loadASSIGN_SAR(binaryNode); 809 return false; 810 } 811 812 @Override 813 public boolean enterASSIGN_SHL(final BinaryNode binaryNode) { 814 loadASSIGN_SHL(binaryNode); 815 return false; 816 } 817 818 @Override 819 public boolean enterASSIGN_SHR(final BinaryNode binaryNode) { 820 loadASSIGN_SHR(binaryNode); 821 return false; 822 } 823 824 @Override 825 public boolean enterASSIGN_SUB(final BinaryNode binaryNode) { 826 loadASSIGN_SUB(binaryNode); 827 return false; 828 } 829 830 @Override 831 public boolean enterCallNode(final CallNode callNode) { 832 return loadCallNode(callNode, resultBounds); 833 } 834 835 @Override 836 public boolean enterLiteralNode(final LiteralNode<?> literalNode) { 837 loadLiteral(literalNode, resultBounds); 838 return false; 839 } 840 841 @Override 842 public boolean enterTernaryNode(final TernaryNode ternaryNode) { 843 loadTernaryNode(ternaryNode, resultBounds); 844 return false; 845 } 846 847 @Override 848 public boolean enterADD(final BinaryNode binaryNode) { 849 loadADD(binaryNode, resultBounds); 850 return false; 851 } 852 853 @Override 854 public boolean enterSUB(final UnaryNode unaryNode) { 855 loadSUB(unaryNode, resultBounds); 856 return false; 857 } 858 859 @Override 860 public boolean enterSUB(final BinaryNode binaryNode) { 861 loadSUB(binaryNode, resultBounds); 862 return false; 863 } 864 865 @Override 866 public boolean enterMUL(final BinaryNode binaryNode) { 867 loadMUL(binaryNode, resultBounds); 868 return false; 869 } 870 871 @Override 872 public boolean enterDIV(final BinaryNode binaryNode) { 873 loadDIV(binaryNode, resultBounds); 874 return false; 875 } 876 877 @Override 878 public boolean enterMOD(final BinaryNode binaryNode) { 879 loadMOD(binaryNode, resultBounds); 880 return false; 881 } 882 883 @Override 884 public boolean enterSAR(final BinaryNode binaryNode) { 885 loadSAR(binaryNode); 886 return false; 887 } 888 889 @Override 890 public boolean enterSHL(final BinaryNode binaryNode) { 891 loadSHL(binaryNode); 892 return false; 893 } 894 895 @Override 896 public boolean enterSHR(final BinaryNode binaryNode) { 897 loadSHR(binaryNode); 898 return false; 899 } 900 901 @Override 902 public boolean enterCOMMALEFT(final BinaryNode binaryNode) { 903 loadCOMMALEFT(binaryNode, resultBounds); 904 return false; 905 } 906 907 @Override 908 public boolean enterCOMMARIGHT(final BinaryNode binaryNode) { 909 loadCOMMARIGHT(binaryNode, resultBounds); 910 return false; 911 } 912 913 @Override 914 public boolean enterAND(final BinaryNode binaryNode) { 915 loadAND_OR(binaryNode, resultBounds, true); 916 return false; 917 } 918 919 @Override 920 public boolean enterOR(final BinaryNode binaryNode) { 921 loadAND_OR(binaryNode, resultBounds, false); 922 return false; 923 } 924 925 @Override 926 public boolean enterNOT(final UnaryNode unaryNode) { 927 loadNOT(unaryNode); 928 return false; 929 } 930 931 @Override 932 public boolean enterADD(final UnaryNode unaryNode) { 933 loadADD(unaryNode, resultBounds); 934 return false; 935 } 936 937 @Override 938 public boolean enterBIT_NOT(final UnaryNode unaryNode) { 939 loadBIT_NOT(unaryNode); 940 return false; 941 } 942 943 @Override 944 public boolean enterBIT_AND(final BinaryNode binaryNode) { 945 loadBIT_AND(binaryNode); 946 return false; 947 } 948 949 @Override 950 public boolean enterBIT_OR(final BinaryNode binaryNode) { 951 loadBIT_OR(binaryNode); 952 return false; 953 } 954 955 @Override 956 public boolean enterBIT_XOR(final BinaryNode binaryNode) { 957 loadBIT_XOR(binaryNode); 958 return false; 959 } 960 961 @Override 962 public boolean enterVOID(final UnaryNode unaryNode) { 963 loadVOID(unaryNode, resultBounds); 964 return false; 965 } 966 967 @Override 968 public boolean enterEQ(final BinaryNode binaryNode) { 969 loadCmp(binaryNode, Condition.EQ); 970 return false; 971 } 972 973 @Override 974 public boolean enterEQ_STRICT(final BinaryNode binaryNode) { 975 loadCmp(binaryNode, Condition.EQ); 976 return false; 977 } 978 979 @Override 980 public boolean enterGE(final BinaryNode binaryNode) { 981 loadCmp(binaryNode, Condition.GE); 982 return false; 983 } 984 985 @Override 986 public boolean enterGT(final BinaryNode binaryNode) { 987 loadCmp(binaryNode, Condition.GT); 988 return false; 989 } 990 991 @Override 992 public boolean enterLE(final BinaryNode binaryNode) { 993 loadCmp(binaryNode, Condition.LE); 994 return false; 995 } 996 997 @Override 998 public boolean enterLT(final BinaryNode binaryNode) { 999 loadCmp(binaryNode, Condition.LT); 1000 return false; 1001 } 1002 1003 @Override 1004 public boolean enterNE(final BinaryNode binaryNode) { 1005 loadCmp(binaryNode, Condition.NE); 1006 return false; 1007 } 1008 1009 @Override 1010 public boolean enterNE_STRICT(final BinaryNode binaryNode) { 1011 loadCmp(binaryNode, Condition.NE); 1012 return false; 1013 } 1014 1015 @Override 1016 public boolean enterObjectNode(final ObjectNode objectNode) { 1017 loadObjectNode(objectNode); 1018 return false; 1019 } 1020 1021 @Override 1022 public boolean enterRuntimeNode(final RuntimeNode runtimeNode) { 1023 loadRuntimeNode(runtimeNode); 1024 return false; 1025 } 1026 1027 @Override 1028 public boolean enterNEW(final UnaryNode unaryNode) { 1029 loadNEW(unaryNode); 1030 return false; 1031 } 1032 1033 @Override 1034 public boolean enterDECINC(final UnaryNode unaryNode) { 1035 loadDECINC(unaryNode); 1036 return false; 1037 } 1038 1039 @Override 1040 public boolean enterJoinPredecessorExpression(final JoinPredecessorExpression joinExpr) { 1041 loadExpression(joinExpr.getExpression(), resultBounds); 1042 return false; 1043 } 1044 1045 @Override 1046 public boolean enterDefault(final Node otherNode) { 1047 // Must have handled all expressions that can legally be encountered. 1048 throw new AssertionError(otherNode.getClass().getName()); 1049 } 1050 }); 1051 if(currentDiscard != expr) { 1052 coerceStackTop(resultBounds); 1053 } 1054 return method; 1055 } 1056 1057 private MethodEmitter coerceStackTop(final TypeBounds typeBounds) { 1058 return method.convert(typeBounds.within(method.peekType())); 1059 } 1060 1061 /** 1062 * Closes any still open entries for this block's local variables in the bytecode local variable table. 1063 * 1064 * @param block block containing symbols. 1065 */ 1066 private void closeBlockVariables(final Block block) { 1067 for (final Symbol symbol : block.getSymbols()) { 1068 if (symbol.isBytecodeLocal()) { 1069 method.closeLocalVariable(symbol, block.getBreakLabel()); 1070 } 1071 } 1072 } 1073 1074 @Override 1075 public boolean enterBlock(final Block block) { 1076 method.label(block.getEntryLabel()); 1077 if(!method.isReachable()) { 1078 return false; 1079 } 1080 if(lc.isFunctionBody() && emittedMethods.contains(lc.getCurrentFunction().getName())) { 1081 return false; 1082 } 1083 initLocals(block); 1084 1085 assert lc.getUsedSlotCount() == method.getFirstTemp(); 1086 return true; 1087 } 1088 1089 private boolean useOptimisticTypes() { 1090 return !lc.inSplitNode() && compiler.useOptimisticTypes(); 1091 } 1092 1093 @Override 1094 public Node leaveBlock(final Block block) { 1095 popBlockScope(block); 1096 method.beforeJoinPoint(block); 1097 1098 closeBlockVariables(block); 1099 lc.releaseSlots(); 1100 assert !method.isReachable() || (lc.isFunctionBody() ? 0 : lc.getUsedSlotCount()) == method.getFirstTemp() : 1101 "reachable="+method.isReachable() + 1102 " isFunctionBody=" + lc.isFunctionBody() + 1103 " usedSlotCount=" + lc.getUsedSlotCount() + 1104 " firstTemp=" + method.getFirstTemp(); 1105 1106 return block; 1107 } 1108 1109 private void popBlockScope(final Block block) { 1110 final Label breakLabel = block.getBreakLabel(); 1111 1112 if(!block.needsScope() || lc.isFunctionBody()) { 1113 emitBlockBreakLabel(breakLabel); 1114 return; 1115 } 1116 1117 final Label beginTryLabel = scopeEntryLabels.pop(); 1118 final Label recoveryLabel = new Label("block_popscope_catch"); 1119 emitBlockBreakLabel(breakLabel); 1120 final boolean bodyCanThrow = breakLabel.isAfter(beginTryLabel); 1121 if(bodyCanThrow) { 1122 method._try(beginTryLabel, breakLabel, recoveryLabel); 1123 } 1124 1125 Label afterCatchLabel = null; 1126 1127 if(method.isReachable()) { 1128 popScope(); 1129 if(bodyCanThrow) { 1130 afterCatchLabel = new Label("block_after_catch"); 1131 method._goto(afterCatchLabel); 1132 } 1133 } 1134 1135 if(bodyCanThrow) { 1136 assert !method.isReachable(); 1137 method._catch(recoveryLabel); 1138 popScopeException(); 1139 method.athrow(); 1140 } 1141 if(afterCatchLabel != null) { 1142 method.label(afterCatchLabel); 1143 } 1144 } 1145 1146 private void emitBlockBreakLabel(final Label breakLabel) { 1147 // TODO: this is totally backwards. Block should not be breakable, LabelNode should be breakable. 1148 final LabelNode labelNode = lc.getCurrentBlockLabelNode(); 1149 if(labelNode != null) { 1150 // Only have conversions if we're reachable 1151 assert labelNode.getLocalVariableConversion() == null || method.isReachable(); 1152 method.beforeJoinPoint(labelNode); 1153 method.breakLabel(breakLabel, labeledBlockBreakLiveLocals.pop()); 1154 } else { 1155 method.label(breakLabel); 1156 } 1157 } 1158 1159 private void popScope() { 1160 popScopes(1); 1161 } 1162 1163 /** 1164 * Pop scope as part of an exception handler. Similar to {@code popScope()} but also takes care of adjusting the 1165 * number of scopes that needs to be popped in case a rest-of continuation handler encounters an exception while 1166 * performing a ToPrimitive conversion. 1167 */ 1168 private void popScopeException() { 1169 popScope(); 1170 final ContinuationInfo ci = getContinuationInfo(); 1171 if(ci != null) { 1172 final Label catchLabel = ci.catchLabel; 1173 if(catchLabel != METHOD_BOUNDARY && catchLabel == catchLabels.peek()) { 1174 ++ci.exceptionScopePops; 1175 } 1176 } 1177 } 1178 1179 private void popScopesUntil(final LexicalContextNode until) { 1180 popScopes(lc.getScopeNestingLevelTo(until)); 1181 } 1182 1183 private void popScopes(final int count) { 1184 if(count == 0) { 1185 return; 1186 } 1187 assert count > 0; // together with count == 0 check, asserts nonnegative count 1188 if (!method.hasScope()) { 1189 // We can sometimes invoke this method even if the method has no slot for the scope object. Typical example: 1190 // for(;;) { with({}) { break; } }. WithNode normally creates a scope, but if it uses no identifiers and 1191 // nothing else forces creation of a scope in the method, we just won't have the :scope local variable. 1192 return; 1193 } 1194 method.loadCompilerConstant(SCOPE); 1195 for(int i = 0; i < count; ++i) { 1196 method.invoke(ScriptObject.GET_PROTO); 1197 } 1198 method.storeCompilerConstant(SCOPE); 1199 } 1200 1201 @Override 1202 public boolean enterBreakNode(final BreakNode breakNode) { 1203 if(!method.isReachable()) { 1204 return false; 1205 } 1206 enterStatement(breakNode); 1207 1208 method.beforeJoinPoint(breakNode); 1209 final BreakableNode breakFrom = lc.getBreakable(breakNode.getLabelName()); 1210 popScopesUntil(breakFrom); 1211 final Label breakLabel = breakFrom.getBreakLabel(); 1212 breakLabel.markAsBreakTarget(); 1213 method.splitAwareGoto(lc, breakLabel, breakFrom); 1214 1215 return false; 1216 } 1217 1218 private int loadArgs(final List<Expression> args) { 1219 final int argCount = args.size(); 1220 // arg have already been converted to objects here. 1221 if (argCount > LinkerCallSite.ARGLIMIT) { 1222 loadArgsArray(args); 1223 return 1; 1224 } 1225 1226 for (final Expression arg : args) { 1227 assert arg != null; 1228 loadExpressionUnbounded(arg); 1229 } 1230 return argCount; 1231 } 1232 1233 private boolean loadCallNode(final CallNode callNode, final TypeBounds resultBounds) { 1234 lineNumber(callNode.getLineNumber()); 1235 1236 final List<Expression> args = callNode.getArgs(); 1237 final Expression function = callNode.getFunction(); 1238 final Block currentBlock = lc.getCurrentBlock(); 1239 final CodeGeneratorLexicalContext codegenLexicalContext = lc; 1240 1241 function.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 1242 1243 private MethodEmitter sharedScopeCall(final IdentNode identNode, final int flags) { 1244 final Symbol symbol = identNode.getSymbol(); 1245 final boolean isFastScope = isFastScope(symbol); 1246 final int scopeCallFlags = flags | (isFastScope ? CALLSITE_FAST_SCOPE : 0); 1247 new OptimisticOperation(callNode, resultBounds) { 1248 @Override 1249 void loadStack() { 1250 method.loadCompilerConstant(SCOPE); 1251 if (isFastScope) { 1252 method.load(getScopeProtoDepth(currentBlock, symbol)); 1253 } else { 1254 method.load(-1); // Bypass fast-scope code in shared callsite 1255 } 1256 loadArgs(args); 1257 } 1258 @Override 1259 void consumeStack() { 1260 final Type[] paramTypes = method.getTypesFromStack(args.size()); 1261 // We have trouble finding e.g. in Type.typeFor(asm.Type) because it can't see the Context class 1262 // loader, so we need to weaken reference signatures to Object. 1263 for(int i = 0; i < paramTypes.length; ++i) { 1264 paramTypes[i] = Type.generic(paramTypes[i]); 1265 } 1266 // As shared scope calls are only used in non-optimistic compilation, we switch from using 1267 // TypeBounds to just a single definitive type, resultBounds.widest. 1268 final SharedScopeCall scopeCall = codegenLexicalContext.getScopeCall(unit, symbol, 1269 identNode.getType(), resultBounds.widest, paramTypes, scopeCallFlags); 1270 scopeCall.generateInvoke(method); 1271 } 1272 }.emit(); 1273 return method; 1274 } 1275 1276 private void scopeCall(final IdentNode ident, final int flags) { 1277 new OptimisticOperation(callNode, resultBounds) { 1278 int argsCount; 1279 @Override 1280 void loadStack() { 1281 loadExpressionAsObject(ident); // foo() makes no sense if foo == 3 1282 // ScriptFunction will see CALLSITE_SCOPE and will bind scope accordingly. 1283 method.loadUndefined(Type.OBJECT); //the 'this' 1284 argsCount = loadArgs(args); 1285 } 1286 @Override 1287 void consumeStack() { 1288 dynamicCall(2 + argsCount, flags); 1289 } 1290 }.emit(); 1291 } 1292 1293 private void evalCall(final IdentNode ident, final int flags) { 1294 final Label invoke_direct_eval = new Label("invoke_direct_eval"); 1295 final Label is_not_eval = new Label("is_not_eval"); 1296 final Label eval_done = new Label("eval_done"); 1297 1298 new OptimisticOperation(callNode, resultBounds) { 1299 int argsCount; 1300 @Override 1301 void loadStack() { 1302 /** 1303 * We want to load 'eval' to check if it is indeed global builtin eval. 1304 * If this eval call is inside a 'with' statement, dyn:getMethod|getProp|getElem 1305 * would be generated if ident is a "isFunction". But, that would result in a 1306 * bound function from WithObject. We don't want that as bound function as that 1307 * won't be detected as builtin eval. So, we make ident as "not a function" which 1308 * results in "dyn:getProp|getElem|getMethod" being generated and so WithObject 1309 * would return unbounded eval function. 1310 * 1311 * Example: 1312 * 1313 * var global = this; 1314 * function func() { 1315 * with({ eval: global.eval) { eval("var x = 10;") } 1316 * } 1317 */ 1318 loadExpressionAsObject(ident.setIsNotFunction()); // Type.OBJECT as foo() makes no sense if foo == 3 1319 globalIsEval(); 1320 method.ifeq(is_not_eval); 1321 1322 // Load up self (scope). 1323 method.loadCompilerConstant(SCOPE); 1324 final List<Expression> evalArgs = callNode.getEvalArgs().getArgs(); 1325 // load evaluated code 1326 loadExpressionAsObject(evalArgs.get(0)); 1327 // load second and subsequent args for side-effect 1328 final int numArgs = evalArgs.size(); 1329 for (int i = 1; i < numArgs; i++) { 1330 loadAndDiscard(evalArgs.get(i)); 1331 } 1332 method._goto(invoke_direct_eval); 1333 1334 method.label(is_not_eval); 1335 // load this time but with dyn:getMethod|getProp|getElem 1336 loadExpressionAsObject(ident); // Type.OBJECT as foo() makes no sense if foo == 3 1337 // This is some scope 'eval' or global eval replaced by user 1338 // but not the built-in ECMAScript 'eval' function call 1339 method.loadNull(); 1340 argsCount = loadArgs(callNode.getArgs()); 1341 } 1342 1343 @Override 1344 void consumeStack() { 1345 // Ordinary call 1346 dynamicCall(2 + argsCount, flags); 1347 method._goto(eval_done); 1348 1349 method.label(invoke_direct_eval); 1350 // Special/extra 'eval' arguments. These can be loaded late (in consumeStack) as we know none of 1351 // them can ever be optimistic. 1352 method.loadCompilerConstant(THIS); 1353 method.load(callNode.getEvalArgs().getLocation()); 1354 method.load(CodeGenerator.this.lc.getCurrentFunction().isStrict()); 1355 // direct call to Global.directEval 1356 globalDirectEval(); 1357 convertOptimisticReturnValue(); 1358 coerceStackTop(resultBounds); 1359 } 1360 }.emit(); 1361 1362 method.label(eval_done); 1363 } 1364 1365 @Override 1366 public boolean enterIdentNode(final IdentNode node) { 1367 final Symbol symbol = node.getSymbol(); 1368 1369 if (symbol.isScope()) { 1370 final int flags = getCallSiteFlags() | CALLSITE_SCOPE; 1371 final int useCount = symbol.getUseCount(); 1372 1373 // Threshold for generating shared scope callsite is lower for fast scope symbols because we know 1374 // we can dial in the correct scope. However, we also need to enable it for non-fast scopes to 1375 // support huge scripts like mandreel.js. 1376 if (callNode.isEval()) { 1377 evalCall(node, flags); 1378 } else if (useCount <= SharedScopeCall.FAST_SCOPE_CALL_THRESHOLD 1379 || !isFastScope(symbol) && useCount <= SharedScopeCall.SLOW_SCOPE_CALL_THRESHOLD 1380 || CodeGenerator.this.lc.inDynamicScope() 1381 || isOptimisticOrRestOf()) { 1382 scopeCall(node, flags); 1383 } else { 1384 sharedScopeCall(node, flags); 1385 } 1386 assert method.peekType().equals(resultBounds.within(callNode.getType())) : method.peekType() + " != " + resultBounds + "(" + callNode.getType() + ")"; 1387 } else { 1388 enterDefault(node); 1389 } 1390 1391 return false; 1392 } 1393 1394 @Override 1395 public boolean enterAccessNode(final AccessNode node) { 1396 //check if this is an apply to call node. only real applies, that haven't been 1397 //shadowed from their way to the global scope counts 1398 1399 //call nodes have program points. 1400 1401 final int flags = getCallSiteFlags() | (callNode.isApplyToCall() ? CALLSITE_APPLY_TO_CALL : 0); 1402 1403 new OptimisticOperation(callNode, resultBounds) { 1404 int argCount; 1405 @Override 1406 void loadStack() { 1407 loadExpressionAsObject(node.getBase()); 1408 method.dup(); 1409 // NOTE: not using a nested OptimisticOperation on this dynamicGet, as we expect to get back 1410 // a callable object. Nobody in their right mind would optimistically type this call site. 1411 assert !node.isOptimistic(); 1412 method.dynamicGet(node.getType(), node.getProperty(), flags, true); 1413 method.swap(); 1414 argCount = loadArgs(args); 1415 } 1416 @Override 1417 void consumeStack() { 1418 dynamicCall(2 + argCount, flags); 1419 } 1420 }.emit(); 1421 1422 return false; 1423 } 1424 1425 @Override 1426 public boolean enterFunctionNode(final FunctionNode origCallee) { 1427 new OptimisticOperation(callNode, resultBounds) { 1428 FunctionNode callee; 1429 int argsCount; 1430 @Override 1431 void loadStack() { 1432 callee = (FunctionNode)origCallee.accept(CodeGenerator.this); 1433 if (callee.isStrict()) { // "this" is undefined 1434 method.loadUndefined(Type.OBJECT); 1435 } else { // get global from scope (which is the self) 1436 globalInstance(); 1437 } 1438 argsCount = loadArgs(args); 1439 } 1440 1441 @Override 1442 void consumeStack() { 1443 final int flags = getCallSiteFlags(); 1444 //assert callNodeType.equals(callee.getReturnType()) : callNodeType + " != " + callee.getReturnType(); 1445 dynamicCall(2 + argsCount, flags); 1446 } 1447 }.emit(); 1448 return false; 1449 } 1450 1451 @Override 1452 public boolean enterIndexNode(final IndexNode node) { 1453 new OptimisticOperation(callNode, resultBounds) { 1454 int argsCount; 1455 @Override 1456 void loadStack() { 1457 loadExpressionAsObject(node.getBase()); 1458 method.dup(); 1459 final Type indexType = node.getIndex().getType(); 1460 if (indexType.isObject() || indexType.isBoolean()) { 1461 loadExpressionAsObject(node.getIndex()); //TODO boolean 1462 } else { 1463 loadExpressionUnbounded(node.getIndex()); 1464 } 1465 // NOTE: not using a nested OptimisticOperation on this dynamicGetIndex, as we expect to get 1466 // back a callable object. Nobody in their right mind would optimistically type this call site. 1467 assert !node.isOptimistic(); 1468 method.dynamicGetIndex(node.getType(), getCallSiteFlags(), true); 1469 method.swap(); 1470 argsCount = loadArgs(args); 1471 } 1472 @Override 1473 void consumeStack() { 1474 final int flags = getCallSiteFlags(); 1475 dynamicCall(2 + argsCount, flags); 1476 } 1477 }.emit(); 1478 return false; 1479 } 1480 1481 @Override 1482 protected boolean enterDefault(final Node node) { 1483 new OptimisticOperation(callNode, resultBounds) { 1484 int argsCount; 1485 @Override 1486 void loadStack() { 1487 // Load up function. 1488 loadExpressionAsObject(function); //TODO, e.g. booleans can be used as functions 1489 method.loadUndefined(Type.OBJECT); // ScriptFunction will figure out the correct this when it sees CALLSITE_SCOPE 1490 argsCount = loadArgs(args); 1491 } 1492 @Override 1493 void consumeStack() { 1494 final int flags = getCallSiteFlags() | CALLSITE_SCOPE; 1495 dynamicCall(2 + argsCount, flags); 1496 } 1497 }.emit(); 1498 return false; 1499 } 1500 }); 1501 1502 return false; 1503 } 1504 1505 /** 1506 * Returns the flags with optimistic flag and program point removed. 1507 * @param flags the flags that need optimism stripped from them. 1508 * @return flags without optimism 1509 */ 1510 static int nonOptimisticFlags(final int flags) { 1511 return flags & ~(CALLSITE_OPTIMISTIC | -1 << CALLSITE_PROGRAM_POINT_SHIFT); 1512 } 1513 1514 @Override 1515 public boolean enterContinueNode(final ContinueNode continueNode) { 1516 if(!method.isReachable()) { 1517 return false; 1518 } 1519 enterStatement(continueNode); 1520 method.beforeJoinPoint(continueNode); 1521 1522 final LoopNode continueTo = lc.getContinueTo(continueNode.getLabelName()); 1523 popScopesUntil(continueTo); 1524 final Label continueLabel = continueTo.getContinueLabel(); 1525 continueLabel.markAsBreakTarget(); 1526 method.splitAwareGoto(lc, continueLabel, continueTo); 1527 1528 return false; 1529 } 1530 1531 @Override 1532 public boolean enterEmptyNode(final EmptyNode emptyNode) { 1533 if(!method.isReachable()) { 1534 return false; 1535 } 1536 enterStatement(emptyNode); 1537 1538 return false; 1539 } 1540 1541 @Override 1542 public boolean enterExpressionStatement(final ExpressionStatement expressionStatement) { 1543 if(!method.isReachable()) { 1544 return false; 1545 } 1546 enterStatement(expressionStatement); 1547 1548 loadAndDiscard(expressionStatement.getExpression()); 1549 assert method.getStackSize() == 0; 1550 1551 return false; 1552 } 1553 1554 @Override 1555 public boolean enterBlockStatement(final BlockStatement blockStatement) { 1556 if(!method.isReachable()) { 1557 return false; 1558 } 1559 enterStatement(blockStatement); 1560 1561 blockStatement.getBlock().accept(this); 1562 1563 return false; 1564 } 1565 1566 @Override 1567 public boolean enterForNode(final ForNode forNode) { 1568 if(!method.isReachable()) { 1569 return false; 1570 } 1571 enterStatement(forNode); 1572 if (forNode.isForIn()) { 1573 enterForIn(forNode); 1574 } else { 1575 final Expression init = forNode.getInit(); 1576 if (init != null) { 1577 loadAndDiscard(init); 1578 } 1579 enterForOrWhile(forNode, forNode.getModify()); 1580 } 1581 1582 return false; 1583 } 1584 1585 private void enterForIn(final ForNode forNode) { 1586 loadExpression(forNode.getModify(), TypeBounds.OBJECT); 1587 method.invoke(forNode.isForEach() ? ScriptRuntime.TO_VALUE_ITERATOR : ScriptRuntime.TO_PROPERTY_ITERATOR); 1588 final Symbol iterSymbol = forNode.getIterator(); 1589 final int iterSlot = iterSymbol.getSlot(Type.OBJECT); 1590 method.store(iterSymbol, ITERATOR_TYPE); 1591 1592 method.beforeJoinPoint(forNode); 1593 1594 final Label continueLabel = forNode.getContinueLabel(); 1595 final Label breakLabel = forNode.getBreakLabel(); 1596 1597 method.label(continueLabel); 1598 method.load(ITERATOR_TYPE, iterSlot); 1599 method.invoke(interfaceCallNoLookup(ITERATOR_CLASS, "hasNext", boolean.class)); 1600 final JoinPredecessorExpression test = forNode.getTest(); 1601 final Block body = forNode.getBody(); 1602 if(LocalVariableConversion.hasLiveConversion(test)) { 1603 final Label afterConversion = new Label("for_in_after_test_conv"); 1604 method.ifne(afterConversion); 1605 method.beforeJoinPoint(test); 1606 method._goto(breakLabel); 1607 method.label(afterConversion); 1608 } else { 1609 method.ifeq(breakLabel); 1610 } 1611 1612 new Store<Expression>(forNode.getInit()) { 1613 @Override 1614 protected void storeNonDiscard() { 1615 // This expression is neither part of a discard, nor needs to be left on the stack after it was 1616 // stored, so we override storeNonDiscard to be a no-op. 1617 } 1618 1619 @Override 1620 protected void evaluate() { 1621 method.load(ITERATOR_TYPE, iterSlot); 1622 // TODO: optimistic for-in iteration 1623 method.invoke(interfaceCallNoLookup(ITERATOR_CLASS, "next", Object.class)); 1624 } 1625 }.store(); 1626 body.accept(this); 1627 1628 if(method.isReachable()) { 1629 method._goto(continueLabel); 1630 } 1631 method.label(breakLabel); 1632 } 1633 1634 /** 1635 * Initialize the slots in a frame to undefined. 1636 * 1637 * @param block block with local vars. 1638 */ 1639 private void initLocals(final Block block) { 1640 lc.onEnterBlock(block); 1641 1642 final boolean isFunctionBody = lc.isFunctionBody(); 1643 final FunctionNode function = lc.getCurrentFunction(); 1644 if (isFunctionBody) { 1645 initializeMethodParameters(function); 1646 if(!function.isVarArg()) { 1647 expandParameterSlots(function); 1648 } 1649 if (method.hasScope()) { 1650 if (function.needsParentScope()) { 1651 method.loadCompilerConstant(CALLEE); 1652 method.invoke(ScriptFunction.GET_SCOPE); 1653 } else { 1654 assert function.hasScopeBlock(); 1655 method.loadNull(); 1656 } 1657 method.storeCompilerConstant(SCOPE); 1658 } 1659 if (function.needsArguments()) { 1660 initArguments(function); 1661 } 1662 } 1663 1664 /* 1665 * Determine if block needs scope, if not, just do initSymbols for this block. 1666 */ 1667 if (block.needsScope()) { 1668 /* 1669 * Determine if function is varargs and consequently variables have to 1670 * be in the scope. 1671 */ 1672 final boolean varsInScope = function.allVarsInScope(); 1673 1674 // TODO for LET we can do better: if *block* does not contain any eval/with, we don't need its vars in scope. 1675 1676 final boolean hasArguments = function.needsArguments(); 1677 final List<MapTuple<Symbol>> tuples = new ArrayList<>(); 1678 final Iterator<IdentNode> paramIter = function.getParameters().iterator(); 1679 for (final Symbol symbol : block.getSymbols()) { 1680 if (symbol.isInternal() || symbol.isThis()) { 1681 continue; 1682 } 1683 1684 if (symbol.isVar()) { 1685 assert !varsInScope || symbol.isScope(); 1686 if (varsInScope || symbol.isScope()) { 1687 assert symbol.isScope() : "scope for " + symbol + " should have been set in Lower already " + function.getName(); 1688 assert !symbol.hasSlot() : "slot for " + symbol + " should have been removed in Lower already" + function.getName(); 1689 1690 //this tuple will not be put fielded, as it has no value, just a symbol 1691 tuples.add(new MapTuple<Symbol>(symbol.getName(), symbol, null)); 1692 } else { 1693 assert symbol.hasSlot() || symbol.slotCount() == 0 : symbol + " should have a slot only, no scope"; 1694 } 1695 } else if (symbol.isParam() && (varsInScope || hasArguments || symbol.isScope())) { 1696 assert symbol.isScope() : "scope for " + symbol + " should have been set in AssignSymbols already " + function.getName() + " varsInScope="+varsInScope+" hasArguments="+hasArguments+" symbol.isScope()=" + symbol.isScope(); 1697 assert !(hasArguments && symbol.hasSlot()) : "slot for " + symbol + " should have been removed in Lower already " + function.getName(); 1698 1699 final Type paramType; 1700 final Symbol paramSymbol; 1701 1702 if (hasArguments) { 1703 assert !symbol.hasSlot() : "slot for " + symbol + " should have been removed in Lower already "; 1704 paramSymbol = null; 1705 paramType = null; 1706 } else { 1707 paramSymbol = symbol; 1708 // NOTE: We're relying on the fact here that Block.symbols is a LinkedHashMap, hence it will 1709 // return symbols in the order they were defined, and parameters are defined in the same order 1710 // they appear in the function. That's why we can have a single pass over the parameter list 1711 // with an iterator, always just scanning forward for the next parameter that matches the symbol 1712 // name. 1713 for(;;) { 1714 final IdentNode nextParam = paramIter.next(); 1715 if(nextParam.getName().equals(symbol.getName())) { 1716 paramType = nextParam.getType(); 1717 break; 1718 } 1719 } 1720 } 1721 1722 tuples.add(new MapTuple<Symbol>(symbol.getName(), symbol, paramType, paramSymbol) { 1723 //this symbol will be put fielded, we can't initialize it as undefined with a known type 1724 @Override 1725 public Class<?> getValueType() { 1726 if (OBJECT_FIELDS_ONLY || value == null || paramType == null) { 1727 return Object.class; 1728 } 1729 return paramType.isBoolean() ? Object.class : paramType.getTypeClass(); 1730 } 1731 }); 1732 } 1733 } 1734 1735 /* 1736 * Create a new object based on the symbols and values, generate 1737 * bootstrap code for object 1738 */ 1739 new FieldObjectCreator<Symbol>(this, tuples, true, hasArguments) { 1740 @Override 1741 protected void loadValue(final Symbol value, final Type type) { 1742 method.load(value, type); 1743 } 1744 }.makeObject(method); 1745 // program function: merge scope into global 1746 if (isFunctionBody && function.isProgram()) { 1747 method.invoke(ScriptRuntime.MERGE_SCOPE); 1748 } 1749 1750 method.storeCompilerConstant(SCOPE); 1751 if(!isFunctionBody) { 1752 // Function body doesn't need a try/catch to restore scope, as it'd be a dead store anyway. Allowing it 1753 // actually causes issues with UnwarrantedOptimismException handlers as ASM will sort this handler to 1754 // the top of the exception handler table, so it'll be triggered instead of the UOE handlers. 1755 final Label scopeEntryLabel = new Label("scope_entry"); 1756 scopeEntryLabels.push(scopeEntryLabel); 1757 method.label(scopeEntryLabel); 1758 } 1759 } else if (isFunctionBody && function.isVarArg()) { 1760 // Since we don't have a scope, parameters didn't get assigned array indices by the FieldObjectCreator, so 1761 // we need to assign them separately here. 1762 int nextParam = 0; 1763 for (final IdentNode param : function.getParameters()) { 1764 param.getSymbol().setFieldIndex(nextParam++); 1765 } 1766 } 1767 1768 // Debugging: print symbols? @see --print-symbols flag 1769 printSymbols(block, (isFunctionBody ? "Function " : "Block in ") + (function.getIdent() == null ? "<anonymous>" : function.getIdent().getName())); 1770 } 1771 1772 /** 1773 * Incoming method parameters are always declared on method entry; declare them in the local variable table. 1774 * @param function function for which code is being generated. 1775 */ 1776 private void initializeMethodParameters(final FunctionNode function) { 1777 final Label functionStart = new Label("fn_start"); 1778 method.label(functionStart); 1779 int nextSlot = 0; 1780 if(function.needsCallee()) { 1781 initializeInternalFunctionParameter(CALLEE, function, functionStart, nextSlot++); 1782 } 1783 initializeInternalFunctionParameter(THIS, function, functionStart, nextSlot++); 1784 if(function.isVarArg()) { 1785 initializeInternalFunctionParameter(VARARGS, function, functionStart, nextSlot++); 1786 } else { 1787 for(final IdentNode param: function.getParameters()) { 1788 final Symbol symbol = param.getSymbol(); 1789 if(symbol.isBytecodeLocal()) { 1790 method.initializeMethodParameter(symbol, param.getType(), functionStart); 1791 } 1792 } 1793 } 1794 } 1795 1796 private void initializeInternalFunctionParameter(final CompilerConstants cc, final FunctionNode fn, final Label functionStart, final int slot) { 1797 final Symbol symbol = initializeInternalFunctionOrSplitParameter(cc, fn, functionStart, slot); 1798 // Internal function params (:callee, this, and :varargs) are never expanded to multiple slots 1799 assert symbol.getFirstSlot() == slot; 1800 } 1801 1802 private Symbol initializeInternalFunctionOrSplitParameter(final CompilerConstants cc, final FunctionNode fn, final Label functionStart, final int slot) { 1803 final Symbol symbol = fn.getBody().getExistingSymbol(cc.symbolName()); 1804 final Type type = Type.typeFor(cc.type()); 1805 method.initializeMethodParameter(symbol, type, functionStart); 1806 method.onLocalStore(type, slot); 1807 return symbol; 1808 } 1809 1810 /** 1811 * Parameters come into the method packed into local variable slots next to each other. Nashorn on the other hand 1812 * can use 1-6 slots for a local variable depending on all the types it needs to store. When this method is invoked, 1813 * the symbols are already allocated such wider slots, but the values are still in tightly packed incoming slots, 1814 * and we need to spread them into their new locations. 1815 * @param function the function for which parameter-spreading code needs to be emitted 1816 */ 1817 private void expandParameterSlots(final FunctionNode function) { 1818 final List<IdentNode> parameters = function.getParameters(); 1819 // Calculate the total number of incoming parameter slots 1820 int currentIncomingSlot = function.needsCallee() ? 2 : 1; 1821 for(final IdentNode parameter: parameters) { 1822 currentIncomingSlot += parameter.getType().getSlots(); 1823 } 1824 // Starting from last parameter going backwards, move the parameter values into their new slots. 1825 for(int i = parameters.size(); i-- > 0;) { 1826 final IdentNode parameter = parameters.get(i); 1827 final Type parameterType = parameter.getType(); 1828 final int typeWidth = parameterType.getSlots(); 1829 currentIncomingSlot -= typeWidth; 1830 final Symbol symbol = parameter.getSymbol(); 1831 final int slotCount = symbol.slotCount(); 1832 assert slotCount > 0; 1833 // Scoped parameters must not hold more than one value 1834 assert symbol.isBytecodeLocal() || slotCount == typeWidth; 1835 1836 // Mark it as having its value stored into it by the method invocation. 1837 method.onLocalStore(parameterType, currentIncomingSlot); 1838 if(currentIncomingSlot != symbol.getSlot(parameterType)) { 1839 method.load(parameterType, currentIncomingSlot); 1840 method.store(symbol, parameterType); 1841 } 1842 } 1843 } 1844 1845 private void initArguments(final FunctionNode function) { 1846 method.loadCompilerConstant(VARARGS); 1847 if (function.needsCallee()) { 1848 method.loadCompilerConstant(CALLEE); 1849 } else { 1850 // If function is strict mode, "arguments.callee" is not populated, so we don't necessarily need the 1851 // caller. 1852 assert function.isStrict(); 1853 method.loadNull(); 1854 } 1855 method.load(function.getParameters().size()); 1856 globalAllocateArguments(); 1857 method.storeCompilerConstant(ARGUMENTS); 1858 } 1859 1860 private boolean skipFunction(final FunctionNode functionNode) { 1861 final ScriptEnvironment env = compiler.getScriptEnvironment(); 1862 final boolean lazy = env._lazy_compilation; 1863 final boolean onDemand = compiler.isOnDemandCompilation(); 1864 1865 // If this is on-demand or lazy compilation, don't compile a nested (not topmost) function. 1866 if((onDemand || lazy) && lc.getOutermostFunction() != functionNode) { 1867 return true; 1868 } 1869 1870 // If lazy compiling with optimistic types, don't compile the program eagerly either. It will soon be 1871 // invalidated anyway. In presence of a class cache, this further means that an obsoleted program version 1872 // lingers around. Also, currently loading previously persisted optimistic types information only works if 1873 // we're on-demand compiling a function, so with this strategy the :program method can also have the warmup 1874 // benefit of using previously persisted types. 1875 // NOTE that this means the first compiled class will effectively just have a :createProgramFunction method, and 1876 // the RecompilableScriptFunctionData (RSFD) object in its constants array. It won't even have the :program 1877 // method. This is by design. It does mean that we're wasting one compiler execution (and we could minimize this 1878 // by just running it up to scope depth calculation, which creates the RSFDs and then this limited codegen). 1879 // We could emit an initial separate compile unit with the initial version of :program in it to better utilize 1880 // the compilation pipeline, but that would need more invasive changes, as currently the assumption that 1881 // :program is emitted into the first compilation unit of the function lives in many places. 1882 if(!onDemand && lazy && env._optimistic_types && functionNode.isProgram()) { 1883 return true; 1884 } 1885 1886 return false; 1887 } 1888 1889 @Override 1890 public boolean enterFunctionNode(final FunctionNode functionNode) { 1891 final int fnId = functionNode.getId(); 1892 1893 if (skipFunction(functionNode)) { 1894 // In case we are not generating code for the function, we must create or retrieve the function object and 1895 // load it on the stack here. 1896 newFunctionObject(functionNode, false); 1897 return false; 1898 } 1899 1900 final String fnName = functionNode.getName(); 1901 1902 // NOTE: we only emit the method for a function with the given name once. We can have multiple functions with 1903 // the same name as a result of inlining finally blocks. However, in the future -- with type specialization, 1904 // notably -- we might need to check for both name *and* signature. Of course, even that might not be 1905 // sufficient; the function might have a code dependency on the type of the variables in its enclosing scopes, 1906 // and the type of such a variable can be different in catch and finally blocks. So, in the future we will have 1907 // to decide to either generate a unique method for each inlined copy of the function, maybe figure out its 1908 // exact type closure and deduplicate based on that, or just decide that functions in finally blocks aren't 1909 // worth it, and generate one method with most generic type closure. 1910 if (!emittedMethods.contains(fnName)) { 1911 log.info("=== BEGIN ", fnName); 1912 1913 assert functionNode.getCompileUnit() != null : "no compile unit for " + fnName + " " + Debug.id(functionNode); 1914 unit = lc.pushCompileUnit(functionNode.getCompileUnit()); 1915 assert lc.hasCompileUnits(); 1916 1917 final ClassEmitter classEmitter = unit.getClassEmitter(); 1918 pushMethodEmitter(isRestOf() ? classEmitter.restOfMethod(functionNode) : classEmitter.method(functionNode)); 1919 method.setPreventUndefinedLoad(); 1920 if(useOptimisticTypes()) { 1921 lc.pushUnwarrantedOptimismHandlers(); 1922 } 1923 1924 // new method - reset last line number 1925 lastLineNumber = -1; 1926 1927 method.begin(); 1928 1929 if (isRestOf()) { 1930 final ContinuationInfo ci = new ContinuationInfo(); 1931 fnIdToContinuationInfo.put(fnId, ci); 1932 method.gotoLoopStart(ci.getHandlerLabel()); 1933 } 1934 } 1935 1936 return true; 1937 } 1938 1939 private void pushMethodEmitter(final MethodEmitter newMethod) { 1940 method = lc.pushMethodEmitter(newMethod); 1941 catchLabels.push(METHOD_BOUNDARY); 1942 } 1943 1944 private void popMethodEmitter() { 1945 method = lc.popMethodEmitter(method); 1946 assert catchLabels.peek() == METHOD_BOUNDARY; 1947 catchLabels.pop(); 1948 } 1949 1950 @Override 1951 public Node leaveFunctionNode(final FunctionNode functionNode) { 1952 try { 1953 final boolean markOptimistic; 1954 if (emittedMethods.add(functionNode.getName())) { 1955 markOptimistic = generateUnwarrantedOptimismExceptionHandlers(functionNode); 1956 generateContinuationHandler(); 1957 method.end(); // wrap up this method 1958 unit = lc.popCompileUnit(functionNode.getCompileUnit()); 1959 popMethodEmitter(); 1960 log.info("=== END ", functionNode.getName()); 1961 } else { 1962 markOptimistic = false; 1963 } 1964 1965 FunctionNode newFunctionNode = functionNode.setState(lc, CompilationState.BYTECODE_GENERATED); 1966 if (markOptimistic) { 1967 newFunctionNode = newFunctionNode.setFlag(lc, FunctionNode.IS_DEOPTIMIZABLE); 1968 } 1969 1970 newFunctionObject(newFunctionNode, true); 1971 return newFunctionNode; 1972 } catch (final Throwable t) { 1973 Context.printStackTrace(t); 1974 final VerifyError e = new VerifyError("Code generation bug in \"" + functionNode.getName() + "\": likely stack misaligned: " + t + " " + functionNode.getSource().getName()); 1975 e.initCause(t); 1976 throw e; 1977 } 1978 } 1979 1980 @Override 1981 public boolean enterIfNode(final IfNode ifNode) { 1982 if(!method.isReachable()) { 1983 return false; 1984 } 1985 enterStatement(ifNode); 1986 1987 final Expression test = ifNode.getTest(); 1988 final Block pass = ifNode.getPass(); 1989 final Block fail = ifNode.getFail(); 1990 final boolean hasFailConversion = LocalVariableConversion.hasLiveConversion(ifNode); 1991 1992 final Label failLabel = new Label("if_fail"); 1993 final Label afterLabel = (fail == null && !hasFailConversion) ? null : new Label("if_done"); 1994 1995 emitBranch(test, failLabel, false); 1996 1997 pass.accept(this); 1998 if(method.isReachable() && afterLabel != null) { 1999 method._goto(afterLabel); //don't fallthru to fail block 2000 } 2001 method.label(failLabel); 2002 2003 if (fail != null) { 2004 fail.accept(this); 2005 } else if(hasFailConversion) { 2006 method.beforeJoinPoint(ifNode); 2007 } 2008 2009 if(afterLabel != null) { 2010 method.label(afterLabel); 2011 } 2012 2013 return false; 2014 } 2015 2016 private void emitBranch(final Expression test, final Label label, final boolean jumpWhenTrue) { 2017 new BranchOptimizer(this, method).execute(test, label, jumpWhenTrue); 2018 } 2019 2020 private void enterStatement(final Statement statement) { 2021 lineNumber(statement); 2022 } 2023 2024 private void lineNumber(final Statement statement) { 2025 lineNumber(statement.getLineNumber()); 2026 } 2027 2028 private void lineNumber(final int lineNumber) { 2029 if (lineNumber != lastLineNumber) { 2030 method.lineNumber(lineNumber); 2031 } 2032 lastLineNumber = lineNumber; 2033 } 2034 2035 int getLastLineNumber() { 2036 return lastLineNumber; 2037 } 2038 2039 /** 2040 * Load a list of nodes as an array of a specific type 2041 * The array will contain the visited nodes. 2042 * 2043 * @param arrayLiteralNode the array of contents 2044 * @param arrayType the type of the array, e.g. ARRAY_NUMBER or ARRAY_OBJECT 2045 * 2046 * @return the method generator that was used 2047 */ 2048 private MethodEmitter loadArray(final ArrayLiteralNode arrayLiteralNode, final ArrayType arrayType) { 2049 assert arrayType == Type.INT_ARRAY || arrayType == Type.LONG_ARRAY || arrayType == Type.NUMBER_ARRAY || arrayType == Type.OBJECT_ARRAY; 2050 2051 final Expression[] nodes = arrayLiteralNode.getValue(); 2052 final Object presets = arrayLiteralNode.getPresets(); 2053 final int[] postsets = arrayLiteralNode.getPostsets(); 2054 final Class<?> type = arrayType.getTypeClass(); 2055 final List<ArrayUnit> units = arrayLiteralNode.getUnits(); 2056 2057 loadConstant(presets); 2058 2059 final Type elementType = arrayType.getElementType(); 2060 2061 if (units != null) { 2062 final MethodEmitter savedMethod = method; 2063 final FunctionNode currentFunction = lc.getCurrentFunction(); 2064 2065 for (final ArrayUnit arrayUnit : units) { 2066 unit = lc.pushCompileUnit(arrayUnit.getCompileUnit()); 2067 2068 final String className = unit.getUnitClassName(); 2069 assert unit != null; 2070 final String name = currentFunction.uniqueName(SPLIT_PREFIX.symbolName()); 2071 final String signature = methodDescriptor(type, ScriptFunction.class, Object.class, ScriptObject.class, type); 2072 2073 pushMethodEmitter(unit.getClassEmitter().method(EnumSet.of(Flag.PUBLIC, Flag.STATIC), name, signature)); 2074 2075 method.setFunctionNode(currentFunction); 2076 method.begin(); 2077 2078 defineCommonSplitMethodParameters(); 2079 defineSplitMethodParameter(3, arrayType); 2080 2081 fixScopeSlot(currentFunction); 2082 2083 lc.enterSplitNode(); 2084 2085 final int arraySlot = SPLIT_ARRAY_ARG.slot(); 2086 for (int i = arrayUnit.getLo(); i < arrayUnit.getHi(); i++) { 2087 method.load(arrayType, arraySlot); 2088 storeElement(nodes, elementType, postsets[i]); 2089 } 2090 2091 method.load(arrayType, arraySlot); 2092 method._return(); 2093 lc.exitSplitNode(); 2094 method.end(); 2095 lc.releaseSlots(); 2096 popMethodEmitter(); 2097 2098 assert method == savedMethod; 2099 method.loadCompilerConstant(CALLEE); 2100 method.swap(); 2101 method.loadCompilerConstant(THIS); 2102 method.swap(); 2103 method.loadCompilerConstant(SCOPE); 2104 method.swap(); 2105 method.invokestatic(className, name, signature); 2106 2107 unit = lc.popCompileUnit(unit); 2108 } 2109 2110 return method; 2111 } 2112 2113 if(postsets.length > 0) { 2114 final int arraySlot = method.getUsedSlotsWithLiveTemporaries(); 2115 method.storeTemp(arrayType, arraySlot); 2116 for (final int postset : postsets) { 2117 method.load(arrayType, arraySlot); 2118 storeElement(nodes, elementType, postset); 2119 } 2120 method.load(arrayType, arraySlot); 2121 } 2122 return method; 2123 } 2124 2125 private void storeElement(final Expression[] nodes, final Type elementType, final int index) { 2126 method.load(index); 2127 2128 final Expression element = nodes[index]; 2129 2130 if (element == null) { 2131 method.loadEmpty(elementType); 2132 } else { 2133 loadExpressionAsType(element, elementType); 2134 } 2135 2136 method.arraystore(); 2137 } 2138 2139 private MethodEmitter loadArgsArray(final List<Expression> args) { 2140 final Object[] array = new Object[args.size()]; 2141 loadConstant(array); 2142 2143 for (int i = 0; i < args.size(); i++) { 2144 method.dup(); 2145 method.load(i); 2146 loadExpression(args.get(i), TypeBounds.OBJECT); // variable arity methods always take objects 2147 method.arraystore(); 2148 } 2149 2150 return method; 2151 } 2152 2153 /** 2154 * Load a constant from the constant array. This is only public to be callable from the objects 2155 * subpackage. Do not call directly. 2156 * 2157 * @param string string to load 2158 */ 2159 void loadConstant(final String string) { 2160 final String unitClassName = unit.getUnitClassName(); 2161 final ClassEmitter classEmitter = unit.getClassEmitter(); 2162 final int index = compiler.getConstantData().add(string); 2163 2164 method.load(index); 2165 method.invokestatic(unitClassName, GET_STRING.symbolName(), methodDescriptor(String.class, int.class)); 2166 classEmitter.needGetConstantMethod(String.class); 2167 } 2168 2169 /** 2170 * Load a constant from the constant array. This is only public to be callable from the objects 2171 * subpackage. Do not call directly. 2172 * 2173 * @param object object to load 2174 */ 2175 void loadConstant(final Object object) { 2176 loadConstant(object, unit, method); 2177 } 2178 2179 private void loadConstant(final Object object, final CompileUnit compileUnit, final MethodEmitter methodEmitter) { 2180 final String unitClassName = compileUnit.getUnitClassName(); 2181 final ClassEmitter classEmitter = compileUnit.getClassEmitter(); 2182 final int index = compiler.getConstantData().add(object); 2183 final Class<?> cls = object.getClass(); 2184 2185 if (cls == PropertyMap.class) { 2186 methodEmitter.load(index); 2187 methodEmitter.invokestatic(unitClassName, GET_MAP.symbolName(), methodDescriptor(PropertyMap.class, int.class)); 2188 classEmitter.needGetConstantMethod(PropertyMap.class); 2189 } else if (cls.isArray()) { 2190 methodEmitter.load(index); 2191 final String methodName = ClassEmitter.getArrayMethodName(cls); 2192 methodEmitter.invokestatic(unitClassName, methodName, methodDescriptor(cls, int.class)); 2193 classEmitter.needGetConstantMethod(cls); 2194 } else { 2195 methodEmitter.loadConstants().load(index).arrayload(); 2196 if (object instanceof ArrayData) { 2197 // avoid cast to non-public ArrayData subclass 2198 methodEmitter.checkcast(ArrayData.class); 2199 methodEmitter.invoke(virtualCallNoLookup(ArrayData.class, "copy", ArrayData.class)); 2200 } else if (cls != Object.class) { 2201 methodEmitter.checkcast(cls); 2202 } 2203 } 2204 } 2205 2206 // literal values 2207 private void loadLiteral(final LiteralNode<?> node, final TypeBounds resultBounds) { 2208 final Object value = node.getValue(); 2209 2210 if (value == null) { 2211 method.loadNull(); 2212 } else if (value instanceof Undefined) { 2213 method.loadUndefined(resultBounds.within(Type.OBJECT)); 2214 } else if (value instanceof String) { 2215 final String string = (String)value; 2216 2217 if (string.length() > MethodEmitter.LARGE_STRING_THRESHOLD / 3) { // 3 == max bytes per encoded char 2218 loadConstant(string); 2219 } else { 2220 method.load(string); 2221 } 2222 } else if (value instanceof RegexToken) { 2223 loadRegex((RegexToken)value); 2224 } else if (value instanceof Boolean) { 2225 method.load((Boolean)value); 2226 } else if (value instanceof Integer) { 2227 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) { 2228 method.load((Integer)value); 2229 method.convert(Type.OBJECT); 2230 } else if(!resultBounds.canBeNarrowerThan(Type.NUMBER)) { 2231 method.load(((Integer)value).doubleValue()); 2232 } else if(!resultBounds.canBeNarrowerThan(Type.LONG)) { 2233 method.load(((Integer)value).longValue()); 2234 } else { 2235 method.load((Integer)value); 2236 } 2237 } else if (value instanceof Long) { 2238 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) { 2239 method.load((Long)value); 2240 method.convert(Type.OBJECT); 2241 } else if(!resultBounds.canBeNarrowerThan(Type.NUMBER)) { 2242 method.load(((Long)value).doubleValue()); 2243 } else { 2244 method.load((Long)value); 2245 } 2246 } else if (value instanceof Double) { 2247 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) { 2248 method.load((Double)value); 2249 method.convert(Type.OBJECT); 2250 } else { 2251 method.load((Double)value); 2252 } 2253 } else if (node instanceof ArrayLiteralNode) { 2254 final ArrayLiteralNode arrayLiteral = (ArrayLiteralNode)node; 2255 final ArrayType atype = arrayLiteral.getArrayType(); 2256 loadArray(arrayLiteral, atype); 2257 globalAllocateArray(atype); 2258 } else { 2259 throw new UnsupportedOperationException("Unknown literal for " + node.getClass() + " " + value.getClass() + " " + value); 2260 } 2261 } 2262 2263 private MethodEmitter loadRegexToken(final RegexToken value) { 2264 method.load(value.getExpression()); 2265 method.load(value.getOptions()); 2266 return globalNewRegExp(); 2267 } 2268 2269 private MethodEmitter loadRegex(final RegexToken regexToken) { 2270 if (regexFieldCount > MAX_REGEX_FIELDS) { 2271 return loadRegexToken(regexToken); 2272 } 2273 // emit field 2274 final String regexName = lc.getCurrentFunction().uniqueName(REGEX_PREFIX.symbolName()); 2275 final ClassEmitter classEmitter = unit.getClassEmitter(); 2276 2277 classEmitter.field(EnumSet.of(PRIVATE, STATIC), regexName, Object.class); 2278 regexFieldCount++; 2279 2280 // get field, if null create new regex, finally clone regex object 2281 method.getStatic(unit.getUnitClassName(), regexName, typeDescriptor(Object.class)); 2282 method.dup(); 2283 final Label cachedLabel = new Label("cached"); 2284 method.ifnonnull(cachedLabel); 2285 2286 method.pop(); 2287 loadRegexToken(regexToken); 2288 method.dup(); 2289 method.putStatic(unit.getUnitClassName(), regexName, typeDescriptor(Object.class)); 2290 2291 method.label(cachedLabel); 2292 globalRegExpCopy(); 2293 2294 return method; 2295 } 2296 2297 /** 2298 * Check if a property value contains a particular program point 2299 * @param value value 2300 * @param pp program point 2301 * @return true if it's there. 2302 */ 2303 private static boolean propertyValueContains(final Expression value, final int pp) { 2304 return new Supplier<Boolean>() { 2305 boolean contains; 2306 2307 @Override 2308 public Boolean get() { 2309 value.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 2310 @Override 2311 public boolean enterFunctionNode(final FunctionNode functionNode) { 2312 return false; 2313 } 2314 2315 @Override 2316 public boolean enterObjectNode(final ObjectNode objectNode) { 2317 return false; 2318 } 2319 2320 @Override 2321 public boolean enterDefault(final Node node) { 2322 if (contains) { 2323 return false; 2324 } 2325 if (node instanceof Optimistic && ((Optimistic)node).getProgramPoint() == pp) { 2326 contains = true; 2327 return false; 2328 } 2329 return true; 2330 } 2331 }); 2332 2333 return contains; 2334 } 2335 }.get(); 2336 } 2337 2338 private void loadObjectNode(final ObjectNode objectNode) { 2339 final List<PropertyNode> elements = objectNode.getElements(); 2340 2341 final List<MapTuple<Expression>> tuples = new ArrayList<>(); 2342 final List<PropertyNode> gettersSetters = new ArrayList<>(); 2343 final int ccp = getCurrentContinuationEntryPoint(); 2344 2345 Expression protoNode = null; 2346 boolean restOfProperty = false; 2347 2348 for (final PropertyNode propertyNode : elements) { 2349 final Expression value = propertyNode.getValue(); 2350 final String key = propertyNode.getKeyName(); 2351 // Just use a pseudo-symbol. We just need something non null; use the name and zero flags. 2352 final Symbol symbol = value == null ? null : new Symbol(key, 0); 2353 2354 if (value == null) { 2355 gettersSetters.add(propertyNode); 2356 } else if (propertyNode.getKey() instanceof IdentNode && 2357 key.equals(ScriptObject.PROTO_PROPERTY_NAME)) { 2358 // ES6 draft compliant __proto__ inside object literal 2359 // Identifier key and name is __proto__ 2360 protoNode = value; 2361 continue; 2362 } 2363 2364 restOfProperty |= 2365 value != null && 2366 isValid(ccp) && 2367 propertyValueContains(value, ccp); 2368 2369 //for literals, a value of null means object type, i.e. the value null or getter setter function 2370 //(I think) 2371 final Class<?> valueType = (OBJECT_FIELDS_ONLY || value == null || value.getType().isBoolean()) ? Object.class : value.getType().getTypeClass(); 2372 tuples.add(new MapTuple<Expression>(key, symbol, Type.typeFor(valueType), value) { 2373 @Override 2374 public Class<?> getValueType() { 2375 return type.getTypeClass(); 2376 } 2377 }); 2378 } 2379 2380 final ObjectCreator<?> oc; 2381 if (elements.size() > OBJECT_SPILL_THRESHOLD) { 2382 oc = new SpillObjectCreator(this, tuples); 2383 } else { 2384 oc = new FieldObjectCreator<Expression>(this, tuples) { 2385 @Override 2386 protected void loadValue(final Expression node, final Type type) { 2387 loadExpressionAsType(node, type); 2388 }}; 2389 } 2390 oc.makeObject(method); 2391 2392 //if this is a rest of method and our continuation point was found as one of the values 2393 //in the properties above, we need to reset the map to oc.getMap() in the continuation 2394 //handler 2395 if (restOfProperty) { 2396 final ContinuationInfo ci = getContinuationInfo(); 2397 // Can be set at most once for a single rest-of method 2398 assert ci.getObjectLiteralMap() == null; 2399 ci.setObjectLiteralMap(oc.getMap()); 2400 ci.setObjectLiteralStackDepth(method.getStackSize()); 2401 } 2402 2403 method.dup(); 2404 if (protoNode != null) { 2405 loadExpressionAsObject(protoNode); 2406 // take care of { __proto__: 34 } or some such! 2407 method.convert(Type.OBJECT); 2408 method.invoke(ScriptObject.SET_PROTO_FROM_LITERAL); 2409 } else { 2410 method.invoke(ScriptObject.SET_GLOBAL_OBJECT_PROTO); 2411 } 2412 2413 for (final PropertyNode propertyNode : gettersSetters) { 2414 final FunctionNode getter = propertyNode.getGetter(); 2415 final FunctionNode setter = propertyNode.getSetter(); 2416 2417 assert getter != null || setter != null; 2418 2419 method.dup().loadKey(propertyNode.getKey()); 2420 if (getter == null) { 2421 method.loadNull(); 2422 } else { 2423 getter.accept(this); 2424 } 2425 2426 if (setter == null) { 2427 method.loadNull(); 2428 } else { 2429 setter.accept(this); 2430 } 2431 2432 method.invoke(ScriptObject.SET_USER_ACCESSORS); 2433 } 2434 } 2435 2436 @Override 2437 public boolean enterReturnNode(final ReturnNode returnNode) { 2438 if(!method.isReachable()) { 2439 return false; 2440 } 2441 enterStatement(returnNode); 2442 2443 method.registerReturn(); 2444 2445 final Type returnType = lc.getCurrentFunction().getReturnType(); 2446 2447 final Expression expression = returnNode.getExpression(); 2448 if (expression != null) { 2449 loadExpressionUnbounded(expression); 2450 } else { 2451 method.loadUndefined(returnType); 2452 } 2453 2454 method._return(returnType); 2455 2456 return false; 2457 } 2458 2459 private boolean undefinedCheck(final RuntimeNode runtimeNode, final List<Expression> args) { 2460 final Request request = runtimeNode.getRequest(); 2461 2462 if (!Request.isUndefinedCheck(request)) { 2463 return false; 2464 } 2465 2466 final Expression lhs = args.get(0); 2467 final Expression rhs = args.get(1); 2468 2469 final Symbol lhsSymbol = lhs instanceof IdentNode ? ((IdentNode)lhs).getSymbol() : null; 2470 final Symbol rhsSymbol = rhs instanceof IdentNode ? ((IdentNode)rhs).getSymbol() : null; 2471 // One must be a "undefined" identifier, otherwise we can't get here 2472 assert lhsSymbol != null || rhsSymbol != null; 2473 2474 final Symbol undefinedSymbol; 2475 if (isUndefinedSymbol(lhsSymbol)) { 2476 undefinedSymbol = lhsSymbol; 2477 } else { 2478 assert isUndefinedSymbol(rhsSymbol); 2479 undefinedSymbol = rhsSymbol; 2480 } 2481 2482 assert undefinedSymbol != null; //remove warning 2483 if (!undefinedSymbol.isScope()) { 2484 return false; //disallow undefined as local var or parameter 2485 } 2486 2487 if (lhsSymbol == undefinedSymbol && lhs.getType().isPrimitive()) { 2488 //we load the undefined first. never mind, because this will deoptimize anyway 2489 return false; 2490 } 2491 2492 if(isDeoptimizedExpression(lhs)) { 2493 // This is actually related to "lhs.getType().isPrimitive()" above: any expression being deoptimized in 2494 // the current chain of rest-of compilations used to have a type narrower than Object (so it was primitive). 2495 // We must not perform undefined check specialization for them, as then we'd violate the basic rule of 2496 // "Thou shalt not alter the stack shape between a deoptimized method and any of its (transitive) rest-ofs." 2497 return false; 2498 } 2499 2500 //make sure that undefined has not been overridden or scoped as a local var 2501 //between us and global 2502 if (!compiler.isGlobalSymbol(lc.getCurrentFunction(), "undefined")) { 2503 return false; 2504 } 2505 2506 final boolean isUndefinedCheck = request == Request.IS_UNDEFINED; 2507 final Expression expr = undefinedSymbol == lhsSymbol ? rhs : lhs; 2508 if (expr.getType().isPrimitive()) { 2509 loadAndDiscard(expr); //throw away lhs, but it still needs to be evaluated for side effects, even if not in scope, as it can be optimistic 2510 method.load(!isUndefinedCheck); 2511 } else { 2512 final Label checkTrue = new Label("ud_check_true"); 2513 final Label end = new Label("end"); 2514 loadExpressionAsObject(expr); 2515 method.loadUndefined(Type.OBJECT); 2516 method.if_acmpeq(checkTrue); 2517 method.load(!isUndefinedCheck); 2518 method._goto(end); 2519 method.label(checkTrue); 2520 method.load(isUndefinedCheck); 2521 method.label(end); 2522 } 2523 2524 return true; 2525 } 2526 2527 private static boolean isUndefinedSymbol(final Symbol symbol) { 2528 return symbol != null && "undefined".equals(symbol.getName()); 2529 } 2530 2531 private static boolean isNullLiteral(final Node node) { 2532 return node instanceof LiteralNode<?> && ((LiteralNode<?>) node).isNull(); 2533 } 2534 2535 private boolean nullCheck(final RuntimeNode runtimeNode, final List<Expression> args) { 2536 final Request request = runtimeNode.getRequest(); 2537 2538 if (!Request.isEQ(request) && !Request.isNE(request)) { 2539 return false; 2540 } 2541 2542 assert args.size() == 2 : "EQ or NE or TYPEOF need two args"; 2543 2544 Expression lhs = args.get(0); 2545 Expression rhs = args.get(1); 2546 2547 if (isNullLiteral(lhs)) { 2548 final Expression tmp = lhs; 2549 lhs = rhs; 2550 rhs = tmp; 2551 } 2552 2553 if (!isNullLiteral(rhs)) { 2554 return false; 2555 } 2556 2557 if (!lhs.getType().isObject()) { 2558 return false; 2559 } 2560 2561 if(isDeoptimizedExpression(lhs)) { 2562 // This is actually related to "!lhs.getType().isObject()" above: any expression being deoptimized in 2563 // the current chain of rest-of compilations used to have a type narrower than Object. We must not 2564 // perform null check specialization for them, as then we'd no longer be loading aconst_null on stack 2565 // and thus violate the basic rule of "Thou shalt not alter the stack shape between a deoptimized 2566 // method and any of its (transitive) rest-ofs." 2567 // NOTE also that if we had a representation for well-known constants (e.g. null, 0, 1, -1, etc.) in 2568 // Label$Stack.localLoads then this wouldn't be an issue, as we would never (somewhat ridiculously) 2569 // allocate a temporary local to hold the result of aconst_null before attempting an optimistic 2570 // operation. 2571 return false; 2572 } 2573 2574 // this is a null literal check, so if there is implicit coercion 2575 // involved like {D}x=null, we will fail - this is very rare 2576 final Label trueLabel = new Label("trueLabel"); 2577 final Label falseLabel = new Label("falseLabel"); 2578 final Label endLabel = new Label("end"); 2579 2580 loadExpressionUnbounded(lhs); //lhs 2581 final Label popLabel; 2582 if (!Request.isStrict(request)) { 2583 method.dup(); //lhs lhs 2584 popLabel = new Label("pop"); 2585 } else { 2586 popLabel = null; 2587 } 2588 2589 if (Request.isEQ(request)) { 2590 method.ifnull(!Request.isStrict(request) ? popLabel : trueLabel); 2591 if (!Request.isStrict(request)) { 2592 method.loadUndefined(Type.OBJECT); 2593 method.if_acmpeq(trueLabel); 2594 } 2595 method.label(falseLabel); 2596 method.load(false); 2597 method._goto(endLabel); 2598 if (!Request.isStrict(request)) { 2599 method.label(popLabel); 2600 method.pop(); 2601 } 2602 method.label(trueLabel); 2603 method.load(true); 2604 method.label(endLabel); 2605 } else if (Request.isNE(request)) { 2606 method.ifnull(!Request.isStrict(request) ? popLabel : falseLabel); 2607 if (!Request.isStrict(request)) { 2608 method.loadUndefined(Type.OBJECT); 2609 method.if_acmpeq(falseLabel); 2610 } 2611 method.label(trueLabel); 2612 method.load(true); 2613 method._goto(endLabel); 2614 if (!Request.isStrict(request)) { 2615 method.label(popLabel); 2616 method.pop(); 2617 } 2618 method.label(falseLabel); 2619 method.load(false); 2620 method.label(endLabel); 2621 } 2622 2623 assert runtimeNode.getType().isBoolean(); 2624 method.convert(runtimeNode.getType()); 2625 2626 return true; 2627 } 2628 2629 /** 2630 * Was this expression or any of its subexpressions deoptimized in the current recompilation chain of rest-of methods? 2631 * @param rootExpr the expression being tested 2632 * @return true if the expression or any of its subexpressions was deoptimized in the current recompilation chain. 2633 */ 2634 private boolean isDeoptimizedExpression(final Expression rootExpr) { 2635 if(!isRestOf()) { 2636 return false; 2637 } 2638 return new Supplier<Boolean>() { 2639 boolean contains; 2640 @Override 2641 public Boolean get() { 2642 rootExpr.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 2643 @Override 2644 public boolean enterFunctionNode(final FunctionNode functionNode) { 2645 return false; 2646 } 2647 @Override 2648 public boolean enterDefault(final Node node) { 2649 if(!contains && node instanceof Optimistic) { 2650 final int pp = ((Optimistic)node).getProgramPoint(); 2651 contains = isValid(pp) && isContinuationEntryPoint(pp); 2652 } 2653 return !contains; 2654 } 2655 }); 2656 return contains; 2657 } 2658 }.get(); 2659 } 2660 2661 private void loadRuntimeNode(final RuntimeNode runtimeNode) { 2662 final List<Expression> args = new ArrayList<>(runtimeNode.getArgs()); 2663 if (nullCheck(runtimeNode, args)) { 2664 return; 2665 } else if(undefinedCheck(runtimeNode, args)) { 2666 return; 2667 } 2668 // Revert a false undefined check to a strict equality check 2669 final RuntimeNode newRuntimeNode; 2670 final Request request = runtimeNode.getRequest(); 2671 if (Request.isUndefinedCheck(request)) { 2672 newRuntimeNode = runtimeNode.setRequest(request == Request.IS_UNDEFINED ? Request.EQ_STRICT : Request.NE_STRICT); 2673 } else { 2674 newRuntimeNode = runtimeNode; 2675 } 2676 2677 new OptimisticOperation(newRuntimeNode, TypeBounds.UNBOUNDED) { 2678 @Override 2679 void loadStack() { 2680 for (final Expression arg : args) { 2681 loadExpression(arg, TypeBounds.OBJECT); 2682 } 2683 } 2684 @Override 2685 void consumeStack() { 2686 method.invokestatic( 2687 CompilerConstants.className(ScriptRuntime.class), 2688 newRuntimeNode.getRequest().toString(), 2689 new FunctionSignature( 2690 false, 2691 false, 2692 newRuntimeNode.getType(), 2693 args.size()).toString()); 2694 } 2695 }.emit(); 2696 2697 method.convert(newRuntimeNode.getType()); 2698 } 2699 2700 @Override 2701 public boolean enterSplitNode(final SplitNode splitNode) { 2702 if(!method.isReachable()) { 2703 return false; 2704 } 2705 2706 final CompileUnit splitCompileUnit = splitNode.getCompileUnit(); 2707 2708 final FunctionNode fn = lc.getCurrentFunction(); 2709 final String className = splitCompileUnit.getUnitClassName(); 2710 final String name = splitNode.getName(); 2711 2712 final Type returnType = fn.getReturnType(); 2713 2714 final Class<?> rtype = fn.getReturnType().getTypeClass(); 2715 final boolean needsArguments = fn.needsArguments(); 2716 final Class<?>[] ptypes = needsArguments ? 2717 new Class<?>[] {ScriptFunction.class, Object.class, ScriptObject.class, ScriptObject.class} : 2718 new Class<?>[] {ScriptFunction.class, Object.class, ScriptObject.class}; 2719 2720 final MethodEmitter caller = method; 2721 unit = lc.pushCompileUnit(splitCompileUnit); 2722 2723 final Call splitCall = staticCallNoLookup( 2724 className, 2725 name, 2726 methodDescriptor(rtype, ptypes)); 2727 2728 final MethodEmitter splitEmitter = 2729 splitCompileUnit.getClassEmitter().method( 2730 splitNode, 2731 name, 2732 rtype, 2733 ptypes); 2734 2735 pushMethodEmitter(splitEmitter); 2736 method.setFunctionNode(fn); 2737 2738 assert fn.needsCallee() : "split function should require callee"; 2739 caller.loadCompilerConstant(CALLEE); 2740 caller.loadCompilerConstant(THIS); 2741 caller.loadCompilerConstant(SCOPE); 2742 if (needsArguments) { 2743 caller.loadCompilerConstant(ARGUMENTS); 2744 } 2745 caller.invoke(splitCall); 2746 caller.storeCompilerConstant(RETURN, returnType); 2747 2748 method.begin(); 2749 2750 defineCommonSplitMethodParameters(); 2751 if(needsArguments) { 2752 defineSplitMethodParameter(3, ARGUMENTS); 2753 } 2754 2755 // Copy scope to its target slot as first thing because the original slot could be used by return symbol. 2756 fixScopeSlot(fn); 2757 2758 final int returnSlot = fn.compilerConstant(RETURN).getSlot(returnType); 2759 method.defineBlockLocalVariable(returnSlot, returnSlot + returnType.getSlots()); 2760 method.loadUndefined(returnType); 2761 method.storeCompilerConstant(RETURN, returnType); 2762 2763 lc.enterSplitNode(); 2764 return true; 2765 } 2766 2767 private void defineCommonSplitMethodParameters() { 2768 defineSplitMethodParameter(0, CALLEE); 2769 defineSplitMethodParameter(1, THIS); 2770 defineSplitMethodParameter(2, SCOPE); 2771 } 2772 2773 private void defineSplitMethodParameter(final int slot, final CompilerConstants cc) { 2774 defineSplitMethodParameter(slot, Type.typeFor(cc.type())); 2775 } 2776 2777 private void defineSplitMethodParameter(final int slot, final Type type) { 2778 method.defineBlockLocalVariable(slot, slot + type.getSlots()); 2779 method.onLocalStore(type, slot); 2780 } 2781 2782 private void fixScopeSlot(final FunctionNode functionNode) { 2783 // TODO hack to move the scope to the expected slot (needed because split methods reuse the same slots as the root method) 2784 final int actualScopeSlot = functionNode.compilerConstant(SCOPE).getSlot(SCOPE_TYPE); 2785 final int defaultScopeSlot = SCOPE.slot(); 2786 if (actualScopeSlot != defaultScopeSlot) { 2787 method.defineBlockLocalVariable(actualScopeSlot, actualScopeSlot + 1); 2788 method.load(SCOPE_TYPE, defaultScopeSlot); 2789 method.storeCompilerConstant(SCOPE); 2790 } 2791 } 2792 2793 @Override 2794 public Node leaveSplitNode(final SplitNode splitNode) { 2795 assert method instanceof SplitMethodEmitter; 2796 lc.exitSplitNode(); 2797 final boolean hasReturn = method.hasReturn(); 2798 final SplitMethodEmitter splitMethod = ((SplitMethodEmitter)method); 2799 final List<Label> targets = splitMethod.getExternalTargets(); 2800 final List<BreakableNode> targetNodes = splitMethod.getExternalTargetNodes(); 2801 final Type returnType = lc.getCurrentFunction().getReturnType(); 2802 2803 try { 2804 // Wrap up this method. 2805 2806 if(method.isReachable()) { 2807 method.loadCompilerConstant(RETURN, returnType); 2808 method._return(returnType); 2809 } 2810 method.end(); 2811 2812 lc.releaseSlots(); 2813 2814 unit = lc.popCompileUnit(splitNode.getCompileUnit()); 2815 popMethodEmitter(); 2816 2817 } catch (final Throwable t) { 2818 Context.printStackTrace(t); 2819 final VerifyError e = new VerifyError("Code generation bug in \"" + splitNode.getName() + "\": likely stack misaligned: " + t + " " + getCurrentSource().getName()); 2820 e.initCause(t); 2821 throw e; 2822 } 2823 2824 // Handle return from split method if there was one. 2825 final MethodEmitter caller = method; 2826 final int targetCount = targets.size(); 2827 2828 //no external jump targets or return in switch node 2829 if (!hasReturn && targets.isEmpty()) { 2830 return splitNode; 2831 } 2832 2833 caller.loadCompilerConstant(SCOPE); 2834 caller.checkcast(Scope.class); 2835 caller.invoke(Scope.GET_SPLIT_STATE); 2836 2837 final Label breakLabel = new Label("no_split_state"); 2838 // Split state is -1 for no split state, 0 for return, 1..n+1 for break/continue 2839 2840 //the common case is that we don't need a switch 2841 if (targetCount == 0) { 2842 assert hasReturn; 2843 caller.ifne(breakLabel); 2844 //has to be zero 2845 caller.label(new Label("split_return")); 2846 caller.loadCompilerConstant(RETURN, returnType); 2847 caller._return(returnType); 2848 caller.label(breakLabel); 2849 } else { 2850 assert !targets.isEmpty(); 2851 2852 final int low = hasReturn ? 0 : 1; 2853 final int labelCount = targetCount + 1 - low; 2854 final Label[] labels = new Label[labelCount]; 2855 2856 for (int i = 0; i < labelCount; i++) { 2857 labels[i] = new Label(i == 0 ? "split_return" : "split_" + targets.get(i - 1)); 2858 } 2859 caller.tableswitch(low, targetCount, breakLabel, labels); 2860 for (int i = low; i <= targetCount; i++) { 2861 caller.label(labels[i - low]); 2862 if (i == 0) { 2863 caller.loadCompilerConstant(RETURN, returnType); 2864 caller._return(returnType); 2865 } else { 2866 // Clear split state. 2867 caller.loadCompilerConstant(SCOPE); 2868 caller.checkcast(Scope.class); 2869 caller.load(-1); 2870 caller.invoke(Scope.SET_SPLIT_STATE); 2871 final BreakableNode targetNode = targetNodes.get(i - 1); 2872 final Label label = targets.get(i - 1); 2873 final JoinPredecessor jumpOrigin = splitNode.getJumpOrigin(label); 2874 if(jumpOrigin != null) { 2875 method.beforeJoinPoint(jumpOrigin); 2876 } 2877 popScopesUntil(targetNode); 2878 caller.splitAwareGoto(lc, targets.get(i - 1), targetNode); 2879 } 2880 } 2881 caller.label(breakLabel); 2882 } 2883 2884 // If split has a return and caller is itself a split method it needs to propagate the return. 2885 if (hasReturn) { 2886 caller.setHasReturn(); 2887 } 2888 2889 return splitNode; 2890 } 2891 2892 @Override 2893 public boolean enterSwitchNode(final SwitchNode switchNode) { 2894 if(!method.isReachable()) { 2895 return false; 2896 } 2897 enterStatement(switchNode); 2898 2899 final Expression expression = switchNode.getExpression(); 2900 final List<CaseNode> cases = switchNode.getCases(); 2901 2902 if (cases.isEmpty()) { 2903 // still evaluate expression for side-effects. 2904 loadAndDiscard(expression); 2905 return false; 2906 } 2907 2908 final CaseNode defaultCase = switchNode.getDefaultCase(); 2909 final Label breakLabel = switchNode.getBreakLabel(); 2910 final int liveLocalsOnBreak = method.getUsedSlotsWithLiveTemporaries(); 2911 2912 if (defaultCase != null && cases.size() == 1) { 2913 // default case only 2914 assert cases.get(0) == defaultCase; 2915 loadAndDiscard(expression); 2916 defaultCase.getBody().accept(this); 2917 method.breakLabel(breakLabel, liveLocalsOnBreak); 2918 return false; 2919 } 2920 2921 // NOTE: it can still change in the tableswitch/lookupswitch case if there's no default case 2922 // but we need to add a synthetic default case for local variable conversions 2923 Label defaultLabel = defaultCase != null ? defaultCase.getEntry() : breakLabel; 2924 final boolean hasSkipConversion = LocalVariableConversion.hasLiveConversion(switchNode); 2925 2926 if (switchNode.isInteger()) { 2927 // Tree for sorting values. 2928 final TreeMap<Integer, Label> tree = new TreeMap<>(); 2929 2930 // Build up sorted tree. 2931 for (final CaseNode caseNode : cases) { 2932 final Node test = caseNode.getTest(); 2933 2934 if (test != null) { 2935 final Integer value = (Integer)((LiteralNode<?>)test).getValue(); 2936 final Label entry = caseNode.getEntry(); 2937 2938 // Take first duplicate. 2939 if (!tree.containsKey(value)) { 2940 tree.put(value, entry); 2941 } 2942 } 2943 } 2944 2945 // Copy values and labels to arrays. 2946 final int size = tree.size(); 2947 final Integer[] values = tree.keySet().toArray(new Integer[size]); 2948 final Label[] labels = tree.values().toArray(new Label[size]); 2949 2950 // Discern low, high and range. 2951 final int lo = values[0]; 2952 final int hi = values[size - 1]; 2953 final long range = (long)hi - (long)lo + 1; 2954 2955 // Find an unused value for default. 2956 int deflt = Integer.MIN_VALUE; 2957 for (final int value : values) { 2958 if (deflt == value) { 2959 deflt++; 2960 } else if (deflt < value) { 2961 break; 2962 } 2963 } 2964 2965 // Load switch expression. 2966 loadExpressionUnbounded(expression); 2967 final Type type = expression.getType(); 2968 2969 // If expression not int see if we can convert, if not use deflt to trigger default. 2970 if (!type.isInteger()) { 2971 method.load(deflt); 2972 final Class<?> exprClass = type.getTypeClass(); 2973 method.invoke(staticCallNoLookup(ScriptRuntime.class, "switchTagAsInt", int.class, exprClass.isPrimitive()? exprClass : Object.class, int.class)); 2974 } 2975 2976 if(hasSkipConversion) { 2977 assert defaultLabel == breakLabel; 2978 defaultLabel = new Label("switch_skip"); 2979 } 2980 // TABLESWITCH needs (range + 3) 32-bit values; LOOKUPSWITCH needs ((size * 2) + 2). Choose the one with 2981 // smaller representation, favor TABLESWITCH when they're equal size. 2982 if (range + 1 <= (size * 2) && range <= Integer.MAX_VALUE) { 2983 final Label[] table = new Label[(int)range]; 2984 Arrays.fill(table, defaultLabel); 2985 for (int i = 0; i < size; i++) { 2986 final int value = values[i]; 2987 table[value - lo] = labels[i]; 2988 } 2989 2990 method.tableswitch(lo, hi, defaultLabel, table); 2991 } else { 2992 final int[] ints = new int[size]; 2993 for (int i = 0; i < size; i++) { 2994 ints[i] = values[i]; 2995 } 2996 2997 method.lookupswitch(defaultLabel, ints, labels); 2998 } 2999 // This is a synthetic "default case" used in absence of actual default case, created if we need to apply 3000 // local variable conversions if neither case is taken. 3001 if(hasSkipConversion) { 3002 method.label(defaultLabel); 3003 method.beforeJoinPoint(switchNode); 3004 method._goto(breakLabel); 3005 } 3006 } else { 3007 final Symbol tagSymbol = switchNode.getTag(); 3008 // TODO: we could have non-object tag 3009 final int tagSlot = tagSymbol.getSlot(Type.OBJECT); 3010 loadExpressionAsObject(expression); 3011 method.store(tagSymbol, Type.OBJECT); 3012 3013 for (final CaseNode caseNode : cases) { 3014 final Expression test = caseNode.getTest(); 3015 3016 if (test != null) { 3017 method.load(Type.OBJECT, tagSlot); 3018 loadExpressionAsObject(test); 3019 method.invoke(ScriptRuntime.EQ_STRICT); 3020 method.ifne(caseNode.getEntry()); 3021 } 3022 } 3023 3024 if (defaultCase != null) { 3025 method._goto(defaultLabel); 3026 } else { 3027 method.beforeJoinPoint(switchNode); 3028 method._goto(breakLabel); 3029 } 3030 } 3031 3032 // First case is only reachable through jump 3033 assert !method.isReachable(); 3034 3035 for (final CaseNode caseNode : cases) { 3036 final Label fallThroughLabel; 3037 if(caseNode.getLocalVariableConversion() != null && method.isReachable()) { 3038 fallThroughLabel = new Label("fallthrough"); 3039 method._goto(fallThroughLabel); 3040 } else { 3041 fallThroughLabel = null; 3042 } 3043 method.label(caseNode.getEntry()); 3044 method.beforeJoinPoint(caseNode); 3045 if(fallThroughLabel != null) { 3046 method.label(fallThroughLabel); 3047 } 3048 caseNode.getBody().accept(this); 3049 } 3050 3051 method.breakLabel(breakLabel, liveLocalsOnBreak); 3052 3053 return false; 3054 } 3055 3056 @Override 3057 public boolean enterThrowNode(final ThrowNode throwNode) { 3058 if(!method.isReachable()) { 3059 return false; 3060 } 3061 enterStatement(throwNode); 3062 3063 if (throwNode.isSyntheticRethrow()) { 3064 method.beforeJoinPoint(throwNode); 3065 3066 //do not wrap whatever this is in an ecma exception, just rethrow it 3067 final IdentNode exceptionExpr = (IdentNode)throwNode.getExpression(); 3068 final Symbol exceptionSymbol = exceptionExpr.getSymbol(); 3069 method.load(exceptionSymbol, EXCEPTION_TYPE); 3070 method.checkcast(EXCEPTION_TYPE.getTypeClass()); 3071 method.athrow(); 3072 return false; 3073 } 3074 3075 final Source source = getCurrentSource(); 3076 final Expression expression = throwNode.getExpression(); 3077 final int position = throwNode.position(); 3078 final int line = throwNode.getLineNumber(); 3079 final int column = source.getColumn(position); 3080 3081 // NOTE: we first evaluate the expression, and only after it was evaluated do we create the new ECMAException 3082 // object and then somewhat cumbersomely move it beneath the evaluated expression on the stack. The reason for 3083 // this is that if expression is optimistic (or contains an optimistic subexpression), we'd potentially access 3084 // the not-yet-<init>ialized object on the stack from the UnwarrantedOptimismException handler, and bytecode 3085 // verifier forbids that. 3086 loadExpressionAsObject(expression); 3087 3088 method.load(source.getName()); 3089 method.load(line); 3090 method.load(column); 3091 method.invoke(ECMAException.CREATE); 3092 3093 method.beforeJoinPoint(throwNode); 3094 method.athrow(); 3095 3096 return false; 3097 } 3098 3099 private Source getCurrentSource() { 3100 return lc.getCurrentFunction().getSource(); 3101 } 3102 3103 @Override 3104 public boolean enterTryNode(final TryNode tryNode) { 3105 if(!method.isReachable()) { 3106 return false; 3107 } 3108 enterStatement(tryNode); 3109 3110 final Block body = tryNode.getBody(); 3111 final List<Block> catchBlocks = tryNode.getCatchBlocks(); 3112 final Symbol vmException = tryNode.getException(); 3113 final Label entry = new Label("try"); 3114 final Label recovery = new Label("catch"); 3115 final Label exit = new Label("end_try"); 3116 final Label skip = new Label("skip"); 3117 3118 method.canThrow(recovery); 3119 // Effect any conversions that might be observed at the entry of the catch node before entering the try node. 3120 // This is because even the first instruction in the try block must be presumed to be able to transfer control 3121 // to the catch block. Note that this doesn't kill the original values; in this regard it works a lot like 3122 // conversions of assignments within the try block. 3123 method.beforeTry(tryNode, recovery); 3124 method.label(entry); 3125 catchLabels.push(recovery); 3126 try { 3127 body.accept(this); 3128 } finally { 3129 assert catchLabels.peek() == recovery; 3130 catchLabels.pop(); 3131 } 3132 3133 method.label(exit); 3134 final boolean bodyCanThrow = exit.isAfter(entry); 3135 if(!bodyCanThrow) { 3136 // The body can't throw an exception; don't even bother emitting the catch handlers, they're all dead code. 3137 return false; 3138 } 3139 3140 method._try(entry, exit, recovery, Throwable.class); 3141 3142 if (method.isReachable()) { 3143 method._goto(skip); 3144 } 3145 method._catch(recovery); 3146 method.store(vmException, EXCEPTION_TYPE); 3147 3148 final int catchBlockCount = catchBlocks.size(); 3149 final Label afterCatch = new Label("after_catch"); 3150 for (int i = 0; i < catchBlockCount; i++) { 3151 assert method.isReachable(); 3152 final Block catchBlock = catchBlocks.get(i); 3153 3154 // Because of the peculiarities of the flow control, we need to use an explicit push/enterBlock/leaveBlock 3155 // here. 3156 lc.push(catchBlock); 3157 enterBlock(catchBlock); 3158 3159 final CatchNode catchNode = (CatchNode)catchBlocks.get(i).getStatements().get(0); 3160 final IdentNode exception = catchNode.getException(); 3161 final Expression exceptionCondition = catchNode.getExceptionCondition(); 3162 final Block catchBody = catchNode.getBody(); 3163 3164 new Store<IdentNode>(exception) { 3165 @Override 3166 protected void storeNonDiscard() { 3167 // This expression is neither part of a discard, nor needs to be left on the stack after it was 3168 // stored, so we override storeNonDiscard to be a no-op. 3169 } 3170 3171 @Override 3172 protected void evaluate() { 3173 if (catchNode.isSyntheticRethrow()) { 3174 method.load(vmException, EXCEPTION_TYPE); 3175 return; 3176 } 3177 /* 3178 * If caught object is an instance of ECMAException, then 3179 * bind obj.thrown to the script catch var. Or else bind the 3180 * caught object itself to the script catch var. 3181 */ 3182 final Label notEcmaException = new Label("no_ecma_exception"); 3183 method.load(vmException, EXCEPTION_TYPE).dup()._instanceof(ECMAException.class).ifeq(notEcmaException); 3184 method.checkcast(ECMAException.class); //TODO is this necessary? 3185 method.getField(ECMAException.THROWN); 3186 method.label(notEcmaException); 3187 } 3188 }.store(); 3189 3190 final boolean isConditionalCatch = exceptionCondition != null; 3191 final Label nextCatch; 3192 if (isConditionalCatch) { 3193 loadExpressionAsBoolean(exceptionCondition); 3194 nextCatch = new Label("next_catch"); 3195 method.ifeq(nextCatch); 3196 } else { 3197 nextCatch = null; 3198 } 3199 3200 catchBody.accept(this); 3201 leaveBlock(catchBlock); 3202 lc.pop(catchBlock); 3203 if(method.isReachable()) { 3204 method._goto(afterCatch); 3205 } 3206 if(nextCatch != null) { 3207 method.label(nextCatch); 3208 } 3209 } 3210 3211 assert !method.isReachable(); 3212 // afterCatch could be the same as skip, except that we need to establish that the vmException is dead. 3213 method.label(afterCatch); 3214 if(method.isReachable()) { 3215 method.markDeadLocalVariable(vmException); 3216 } 3217 method.label(skip); 3218 3219 // Finally body is always inlined elsewhere so it doesn't need to be emitted 3220 return false; 3221 } 3222 3223 @Override 3224 public boolean enterVarNode(final VarNode varNode) { 3225 if(!method.isReachable()) { 3226 return false; 3227 } 3228 final Expression init = varNode.getInit(); 3229 3230 if (init == null) { 3231 return false; 3232 } 3233 3234 enterStatement(varNode); 3235 3236 final IdentNode identNode = varNode.getName(); 3237 final Symbol identSymbol = identNode.getSymbol(); 3238 assert identSymbol != null : "variable node " + varNode + " requires a name with a symbol"; 3239 3240 assert method != null; 3241 3242 final boolean needsScope = identSymbol.isScope(); 3243 if (needsScope) { 3244 method.loadCompilerConstant(SCOPE); 3245 } 3246 3247 if (needsScope) { 3248 loadExpressionUnbounded(init); 3249 final int flags = CALLSITE_SCOPE | getCallSiteFlags(); 3250 if (isFastScope(identSymbol)) { 3251 storeFastScopeVar(identSymbol, flags); 3252 } else { 3253 method.dynamicSet(identNode.getName(), flags); 3254 } 3255 } else { 3256 final Type identType = identNode.getType(); 3257 if(identType == Type.UNDEFINED) { 3258 // The symbol must not be slotted; the initializer is either itself undefined (explicit assignment of 3259 // undefined to undefined), or the left hand side is a dead variable. 3260 assert !identNode.getSymbol().isScope(); 3261 assert init.getType() == Type.UNDEFINED || identNode.getSymbol().slotCount() == 0; 3262 loadAndDiscard(init); 3263 return false; 3264 } 3265 loadExpressionAsType(init, identType); 3266 storeIdentWithCatchConversion(identNode, identType); 3267 } 3268 3269 return false; 3270 } 3271 3272 private void storeIdentWithCatchConversion(final IdentNode identNode, final Type type) { 3273 // Assignments happening in try/catch blocks need to ensure that they also store a possibly wider typed value 3274 // that will be live at the exit from the try block 3275 final LocalVariableConversion conversion = identNode.getLocalVariableConversion(); 3276 final Symbol symbol = identNode.getSymbol(); 3277 if(conversion != null && conversion.isLive()) { 3278 assert symbol == conversion.getSymbol(); 3279 assert symbol.isBytecodeLocal(); 3280 // Only a single conversion from the target type to the join type is expected. 3281 assert conversion.getNext() == null; 3282 assert conversion.getFrom() == type; 3283 // We must propagate potential type change to the catch block 3284 final Label catchLabel = catchLabels.peek(); 3285 assert catchLabel != METHOD_BOUNDARY; // ident conversion only exists in try blocks 3286 assert catchLabel.isReachable(); 3287 final Type joinType = conversion.getTo(); 3288 final Label.Stack catchStack = catchLabel.getStack(); 3289 final int joinSlot = symbol.getSlot(joinType); 3290 // With nested try/catch blocks (incl. synthetic ones for finally), we can have a supposed conversion for 3291 // the exception symbol in the nested catch, but it isn't live in the outer catch block, so prevent doing 3292 // conversions for it. E.g. in "try { try { ... } catch(e) { e = 1; } } catch(e2) { ... }", we must not 3293 // introduce an I->O conversion on "e = 1" assignment as "e" is not live in "catch(e2)". 3294 if(catchStack.getUsedSlotsWithLiveTemporaries() > joinSlot) { 3295 method.dup(); 3296 method.convert(joinType); 3297 method.store(symbol, joinType); 3298 catchLabel.getStack().onLocalStore(joinType, joinSlot, true); 3299 method.canThrow(catchLabel); 3300 // Store but keep the previous store live too. 3301 method.store(symbol, type, false); 3302 return; 3303 } 3304 } 3305 3306 method.store(symbol, type, true); 3307 } 3308 3309 @Override 3310 public boolean enterWhileNode(final WhileNode whileNode) { 3311 if(!method.isReachable()) { 3312 return false; 3313 } 3314 if(whileNode.isDoWhile()) { 3315 enterDoWhile(whileNode); 3316 } else { 3317 enterStatement(whileNode); 3318 enterForOrWhile(whileNode, null); 3319 } 3320 return false; 3321 } 3322 3323 private void enterForOrWhile(final LoopNode loopNode, final JoinPredecessorExpression modify) { 3324 // NOTE: the usual pattern for compiling test-first loops is "GOTO test; body; test; IFNE body". We use the less 3325 // conventional "test; IFEQ break; body; GOTO test; break;". It has one extra unconditional GOTO in each repeat 3326 // of the loop, but it's not a problem for modern JIT compilers. We do this because our local variable type 3327 // tracking is unfortunately not really prepared for out-of-order execution, e.g. compiling the following 3328 // contrived but legal JavaScript code snippet would fail because the test changes the type of "i" from object 3329 // to double: var i = {valueOf: function() { return 1} }; while(--i >= 0) { ... } 3330 // Instead of adding more complexity to the local variable type tracking, we instead choose to emit this 3331 // different code shape. 3332 final int liveLocalsOnBreak = method.getUsedSlotsWithLiveTemporaries(); 3333 final JoinPredecessorExpression test = loopNode.getTest(); 3334 if(Expression.isAlwaysFalse(test)) { 3335 loadAndDiscard(test); 3336 return; 3337 } 3338 3339 method.beforeJoinPoint(loopNode); 3340 3341 final Label continueLabel = loopNode.getContinueLabel(); 3342 final Label repeatLabel = modify != null ? new Label("for_repeat") : continueLabel; 3343 method.label(repeatLabel); 3344 final int liveLocalsOnContinue = method.getUsedSlotsWithLiveTemporaries(); 3345 3346 final Block body = loopNode.getBody(); 3347 final Label breakLabel = loopNode.getBreakLabel(); 3348 final boolean testHasLiveConversion = test != null && LocalVariableConversion.hasLiveConversion(test); 3349 3350 if(Expression.isAlwaysTrue(test)) { 3351 if(test != null) { 3352 loadAndDiscard(test); 3353 if(testHasLiveConversion) { 3354 method.beforeJoinPoint(test); 3355 } 3356 } 3357 } else if (test != null) { 3358 if (testHasLiveConversion) { 3359 emitBranch(test.getExpression(), body.getEntryLabel(), true); 3360 method.beforeJoinPoint(test); 3361 method._goto(breakLabel); 3362 } else { 3363 emitBranch(test.getExpression(), breakLabel, false); 3364 } 3365 } 3366 3367 body.accept(this); 3368 if(repeatLabel != continueLabel) { 3369 emitContinueLabel(continueLabel, liveLocalsOnContinue); 3370 } 3371 3372 if(method.isReachable()) { 3373 if(modify != null) { 3374 lineNumber(loopNode); 3375 loadAndDiscard(modify); 3376 method.beforeJoinPoint(modify); 3377 } 3378 method._goto(repeatLabel); 3379 } 3380 3381 method.breakLabel(breakLabel, liveLocalsOnBreak); 3382 } 3383 3384 private void emitContinueLabel(final Label continueLabel, final int liveLocals) { 3385 final boolean reachable = method.isReachable(); 3386 method.breakLabel(continueLabel, liveLocals); 3387 // If we reach here only through a continue statement (e.g. body does not exit normally) then the 3388 // continueLabel can have extra non-temp symbols (e.g. exception from a try/catch contained in the body). We 3389 // must make sure those are thrown away. 3390 if(!reachable) { 3391 method.undefineLocalVariables(lc.getUsedSlotCount(), false); 3392 } 3393 } 3394 3395 private void enterDoWhile(final WhileNode whileNode) { 3396 final int liveLocalsOnContinueOrBreak = method.getUsedSlotsWithLiveTemporaries(); 3397 method.beforeJoinPoint(whileNode); 3398 3399 final Block body = whileNode.getBody(); 3400 body.accept(this); 3401 3402 emitContinueLabel(whileNode.getContinueLabel(), liveLocalsOnContinueOrBreak); 3403 if(method.isReachable()) { 3404 lineNumber(whileNode); 3405 final JoinPredecessorExpression test = whileNode.getTest(); 3406 final Label bodyEntryLabel = body.getEntryLabel(); 3407 final boolean testHasLiveConversion = LocalVariableConversion.hasLiveConversion(test); 3408 if(Expression.isAlwaysFalse(test)) { 3409 loadAndDiscard(test); 3410 if(testHasLiveConversion) { 3411 method.beforeJoinPoint(test); 3412 } 3413 } else if(testHasLiveConversion) { 3414 // If we have conversions after the test in do-while, they need to be effected on both branches. 3415 final Label beforeExit = new Label("do_while_preexit"); 3416 emitBranch(test.getExpression(), beforeExit, false); 3417 method.beforeJoinPoint(test); 3418 method._goto(bodyEntryLabel); 3419 method.label(beforeExit); 3420 method.beforeJoinPoint(test); 3421 } else { 3422 emitBranch(test.getExpression(), bodyEntryLabel, true); 3423 } 3424 } 3425 method.breakLabel(whileNode.getBreakLabel(), liveLocalsOnContinueOrBreak); 3426 } 3427 3428 3429 @Override 3430 public boolean enterWithNode(final WithNode withNode) { 3431 if(!method.isReachable()) { 3432 return false; 3433 } 3434 enterStatement(withNode); 3435 final Expression expression = withNode.getExpression(); 3436 final Block body = withNode.getBody(); 3437 3438 // It is possible to have a "pathological" case where the with block does not reference *any* identifiers. It's 3439 // pointless, but legal. In that case, if nothing else in the method forced the assignment of a slot to the 3440 // scope object, its' possible that it won't have a slot assigned. In this case we'll only evaluate expression 3441 // for its side effect and visit the body, and not bother opening and closing a WithObject. 3442 final boolean hasScope = method.hasScope(); 3443 3444 if (hasScope) { 3445 method.loadCompilerConstant(SCOPE); 3446 } 3447 3448 loadExpressionAsObject(expression); 3449 3450 final Label tryLabel; 3451 if (hasScope) { 3452 // Construct a WithObject if we have a scope 3453 method.invoke(ScriptRuntime.OPEN_WITH); 3454 method.storeCompilerConstant(SCOPE); 3455 tryLabel = new Label("with_try"); 3456 method.label(tryLabel); 3457 } else { 3458 // We just loaded the expression for its side effect and to check 3459 // for null or undefined value. 3460 globalCheckObjectCoercible(); 3461 tryLabel = null; 3462 } 3463 3464 // Always process body 3465 body.accept(this); 3466 3467 if (hasScope) { 3468 // Ensure we always close the WithObject 3469 final Label endLabel = new Label("with_end"); 3470 final Label catchLabel = new Label("with_catch"); 3471 final Label exitLabel = new Label("with_exit"); 3472 3473 method.label(endLabel); 3474 // Somewhat conservatively presume that if the body is not empty, it can throw an exception. In any case, 3475 // we must prevent trying to emit a try-catch for empty range, as it causes a verification error. 3476 final boolean bodyCanThrow = endLabel.isAfter(tryLabel); 3477 if(bodyCanThrow) { 3478 method._try(tryLabel, endLabel, catchLabel); 3479 } 3480 3481 final boolean reachable = method.isReachable(); 3482 if(reachable) { 3483 popScope(); 3484 if(bodyCanThrow) { 3485 method._goto(exitLabel); 3486 } 3487 } 3488 3489 if(bodyCanThrow) { 3490 method._catch(catchLabel); 3491 popScopeException(); 3492 method.athrow(); 3493 if(reachable) { 3494 method.label(exitLabel); 3495 } 3496 } 3497 } 3498 return false; 3499 } 3500 3501 private void loadADD(final UnaryNode unaryNode, final TypeBounds resultBounds) { 3502 loadExpression(unaryNode.getExpression(), resultBounds.booleanToInt().notWiderThan(Type.NUMBER)); 3503 if(method.peekType() == Type.BOOLEAN) { 3504 // It's a no-op in bytecode, but we must make sure it is treated as an int for purposes of type signatures 3505 method.convert(Type.INT); 3506 } 3507 } 3508 3509 private void loadBIT_NOT(final UnaryNode unaryNode) { 3510 loadExpression(unaryNode.getExpression(), TypeBounds.INT).load(-1).xor(); 3511 } 3512 3513 private void loadDECINC(final UnaryNode unaryNode) { 3514 final Expression operand = unaryNode.getExpression(); 3515 final Type type = unaryNode.getType(); 3516 final TypeBounds typeBounds = new TypeBounds(type, Type.NUMBER); 3517 final TokenType tokenType = unaryNode.tokenType(); 3518 final boolean isPostfix = tokenType == TokenType.DECPOSTFIX || tokenType == TokenType.INCPOSTFIX; 3519 final boolean isIncrement = tokenType == TokenType.INCPREFIX || tokenType == TokenType.INCPOSTFIX; 3520 3521 assert !type.isObject(); 3522 3523 new SelfModifyingStore<UnaryNode>(unaryNode, operand) { 3524 3525 private void loadRhs() { 3526 loadExpression(operand, typeBounds, true); 3527 } 3528 3529 @Override 3530 protected void evaluate() { 3531 if(isPostfix) { 3532 loadRhs(); 3533 } else { 3534 new OptimisticOperation(unaryNode, typeBounds) { 3535 @Override 3536 void loadStack() { 3537 loadRhs(); 3538 loadMinusOne(); 3539 } 3540 @Override 3541 void consumeStack() { 3542 doDecInc(getProgramPoint()); 3543 } 3544 }.emit(getOptimisticIgnoreCountForSelfModifyingExpression(operand)); 3545 } 3546 } 3547 3548 @Override 3549 protected void storeNonDiscard() { 3550 super.storeNonDiscard(); 3551 if (isPostfix) { 3552 new OptimisticOperation(unaryNode, typeBounds) { 3553 @Override 3554 void loadStack() { 3555 loadMinusOne(); 3556 } 3557 @Override 3558 void consumeStack() { 3559 doDecInc(getProgramPoint()); 3560 } 3561 }.emit(1); // 1 for non-incremented result on the top of the stack pushed in evaluate() 3562 } 3563 } 3564 3565 private void loadMinusOne() { 3566 if (type.isInteger()) { 3567 method.load(isIncrement ? 1 : -1); 3568 } else if (type.isLong()) { 3569 method.load(isIncrement ? 1L : -1L); 3570 } else { 3571 method.load(isIncrement ? 1.0 : -1.0); 3572 } 3573 } 3574 3575 private void doDecInc(final int programPoint) { 3576 method.add(programPoint); 3577 } 3578 }.store(); 3579 } 3580 3581 private static int getOptimisticIgnoreCountForSelfModifyingExpression(final Expression target) { 3582 return target instanceof AccessNode ? 1 : target instanceof IndexNode ? 2 : 0; 3583 } 3584 3585 private void loadAndDiscard(final Expression expr) { 3586 // TODO: move checks for discarding to actual expression load code (e.g. as we do with void). That way we might 3587 // be able to eliminate even more checks. 3588 if(expr instanceof PrimitiveLiteralNode | isLocalVariable(expr)) { 3589 assert lc.getCurrentDiscard() != expr; 3590 // Don't bother evaluating expressions without side effects. Typical usage is "void 0" for reliably generating 3591 // undefined. 3592 return; 3593 } 3594 3595 lc.pushDiscard(expr); 3596 loadExpression(expr, TypeBounds.UNBOUNDED); 3597 if (lc.getCurrentDiscard() == expr) { 3598 assert !expr.isAssignment(); 3599 // NOTE: if we had a way to load with type void, we could avoid popping 3600 method.pop(); 3601 lc.popDiscard(); 3602 } 3603 } 3604 3605 private void loadNEW(final UnaryNode unaryNode) { 3606 final CallNode callNode = (CallNode)unaryNode.getExpression(); 3607 final List<Expression> args = callNode.getArgs(); 3608 3609 // Load function reference. 3610 loadExpressionAsObject(callNode.getFunction()); // must detect type error 3611 3612 method.dynamicNew(1 + loadArgs(args), getCallSiteFlags()); 3613 } 3614 3615 private void loadNOT(final UnaryNode unaryNode) { 3616 final Expression expr = unaryNode.getExpression(); 3617 if(expr instanceof UnaryNode && expr.isTokenType(TokenType.NOT)) { 3618 // !!x is idiomatic boolean cast in JavaScript 3619 loadExpressionAsBoolean(((UnaryNode)expr).getExpression()); 3620 } else { 3621 final Label trueLabel = new Label("true"); 3622 final Label afterLabel = new Label("after"); 3623 3624 emitBranch(expr, trueLabel, true); 3625 method.load(true); 3626 method._goto(afterLabel); 3627 method.label(trueLabel); 3628 method.load(false); 3629 method.label(afterLabel); 3630 } 3631 } 3632 3633 private void loadSUB(final UnaryNode unaryNode, final TypeBounds resultBounds) { 3634 final Type type = unaryNode.getType(); 3635 assert type.isNumeric(); 3636 final TypeBounds numericBounds = resultBounds.booleanToInt(); 3637 new OptimisticOperation(unaryNode, numericBounds) { 3638 @Override 3639 void loadStack() { 3640 final Expression expr = unaryNode.getExpression(); 3641 loadExpression(expr, numericBounds.notWiderThan(Type.NUMBER)); 3642 } 3643 @Override 3644 void consumeStack() { 3645 // Must do an explicit conversion to the operation's type when it's double so that we correctly handle 3646 // negation of an int 0 to a double -0. With this, we get the correct negation of a local variable after 3647 // it deoptimized, e.g. "iload_2; i2d; dneg". Without this, we get "iload_2; ineg; i2d". 3648 if(type.isNumber()) { 3649 method.convert(type); 3650 } 3651 method.neg(getProgramPoint()); 3652 } 3653 }.emit(); 3654 } 3655 3656 public void loadVOID(final UnaryNode unaryNode, final TypeBounds resultBounds) { 3657 loadAndDiscard(unaryNode.getExpression()); 3658 if(lc.getCurrentDiscard() == unaryNode) { 3659 lc.popDiscard(); 3660 } else { 3661 method.loadUndefined(resultBounds.widest); 3662 } 3663 } 3664 3665 public void loadADD(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3666 new OptimisticOperation(binaryNode, resultBounds) { 3667 @Override 3668 void loadStack() { 3669 final TypeBounds operandBounds; 3670 final boolean isOptimistic = isValid(getProgramPoint()); 3671 if(isOptimistic) { 3672 operandBounds = new TypeBounds(binaryNode.getType(), Type.OBJECT); 3673 } else { 3674 // Non-optimistic, non-FP +. Allow it to overflow. 3675 operandBounds = new TypeBounds(binaryNode.getWidestOperandType(), Type.OBJECT); 3676 } 3677 loadBinaryOperands(binaryNode.lhs(), binaryNode.rhs(), operandBounds, false); 3678 } 3679 3680 @Override 3681 void consumeStack() { 3682 method.add(getProgramPoint()); 3683 } 3684 }.emit(); 3685 } 3686 3687 private void loadAND_OR(final BinaryNode binaryNode, final TypeBounds resultBounds, final boolean isAnd) { 3688 final Type narrowestOperandType = Type.widestReturnType(binaryNode.lhs().getType(), binaryNode.rhs().getType()); 3689 3690 final Label skip = new Label("skip"); 3691 if(narrowestOperandType == Type.BOOLEAN) { 3692 // optimize all-boolean logical expressions 3693 final Label onTrue = new Label("andor_true"); 3694 emitBranch(binaryNode, onTrue, true); 3695 method.load(false); 3696 method._goto(skip); 3697 method.label(onTrue); 3698 method.load(true); 3699 method.label(skip); 3700 return; 3701 } 3702 3703 final TypeBounds outBounds = resultBounds.notNarrowerThan(narrowestOperandType); 3704 final JoinPredecessorExpression lhs = (JoinPredecessorExpression)binaryNode.lhs(); 3705 final boolean lhsConvert = LocalVariableConversion.hasLiveConversion(lhs); 3706 final Label evalRhs = lhsConvert ? new Label("eval_rhs") : null; 3707 3708 loadExpression(lhs, outBounds).dup().convert(Type.BOOLEAN); 3709 if (isAnd) { 3710 if(lhsConvert) { 3711 method.ifne(evalRhs); 3712 } else { 3713 method.ifeq(skip); 3714 } 3715 } else if(lhsConvert) { 3716 method.ifeq(evalRhs); 3717 } else { 3718 method.ifne(skip); 3719 } 3720 3721 if(lhsConvert) { 3722 method.beforeJoinPoint(lhs); 3723 method._goto(skip); 3724 method.label(evalRhs); 3725 } 3726 3727 method.pop(); 3728 final JoinPredecessorExpression rhs = (JoinPredecessorExpression)binaryNode.rhs(); 3729 loadExpression(rhs, outBounds); 3730 method.beforeJoinPoint(rhs); 3731 method.label(skip); 3732 } 3733 3734 private static boolean isLocalVariable(final Expression lhs) { 3735 return lhs instanceof IdentNode && isLocalVariable((IdentNode)lhs); 3736 } 3737 3738 private static boolean isLocalVariable(final IdentNode lhs) { 3739 return lhs.getSymbol().isBytecodeLocal(); 3740 } 3741 3742 // NOTE: does not use resultBounds as the assignment is driven by the type of the RHS 3743 private void loadASSIGN(final BinaryNode binaryNode) { 3744 final Expression lhs = binaryNode.lhs(); 3745 final Expression rhs = binaryNode.rhs(); 3746 3747 final Type rhsType = rhs.getType(); 3748 // Detect dead assignments 3749 if(lhs instanceof IdentNode) { 3750 final Symbol symbol = ((IdentNode)lhs).getSymbol(); 3751 if(!symbol.isScope() && !symbol.hasSlotFor(rhsType) && lc.getCurrentDiscard() == binaryNode) { 3752 loadAndDiscard(rhs); 3753 lc.popDiscard(); 3754 method.markDeadLocalVariable(symbol); 3755 return; 3756 } 3757 } 3758 3759 new Store<BinaryNode>(binaryNode, lhs) { 3760 @Override 3761 protected void evaluate() { 3762 // NOTE: we're loading with "at least as wide as" so optimistic operations on the right hand side 3763 // remain optimistic, and then explicitly convert to the required type if needed. 3764 loadExpressionAsType(rhs, rhsType); 3765 } 3766 }.store(); 3767 } 3768 3769 /** 3770 * Binary self-assignment that can be optimistic: +=, -=, *=, and /=. 3771 */ 3772 private abstract class BinaryOptimisticSelfAssignment extends SelfModifyingStore<BinaryNode> { 3773 3774 /** 3775 * Constructor 3776 * 3777 * @param node the assign op node 3778 */ 3779 BinaryOptimisticSelfAssignment(final BinaryNode node) { 3780 super(node, node.lhs()); 3781 } 3782 3783 protected abstract void op(OptimisticOperation oo); 3784 3785 @Override 3786 protected void evaluate() { 3787 final Expression lhs = assignNode.lhs(); 3788 final Type widest = assignNode.isTokenType(TokenType.ASSIGN_ADD) ? Type.OBJECT : assignNode.getWidestOperationType(); 3789 final TypeBounds bounds = new TypeBounds(assignNode.getType(), widest); 3790 new OptimisticOperation(assignNode, bounds) { 3791 @Override 3792 void loadStack() { 3793 loadBinaryOperands(lhs, assignNode.rhs(), bounds, true); 3794 } 3795 @Override 3796 void consumeStack() { 3797 op(this); 3798 } 3799 }.emit(getOptimisticIgnoreCountForSelfModifyingExpression(lhs)); 3800 method.convert(assignNode.getType()); 3801 } 3802 } 3803 3804 /** 3805 * Non-optimistic binary self-assignment operation. Basically, everything except +=, -=, *=, and /=. 3806 */ 3807 private abstract class BinarySelfAssignment extends SelfModifyingStore<BinaryNode> { 3808 BinarySelfAssignment(final BinaryNode node) { 3809 super(node, node.lhs()); 3810 } 3811 3812 protected abstract void op(); 3813 3814 @Override 3815 protected void evaluate() { 3816 loadBinaryOperands(assignNode.lhs(), assignNode.rhs(), TypeBounds.UNBOUNDED.notWiderThan(assignNode.getWidestOperandType()), true); 3817 op(); 3818 } 3819 } 3820 3821 private void loadASSIGN_ADD(final BinaryNode binaryNode) { 3822 new BinaryOptimisticSelfAssignment(binaryNode) { 3823 @Override 3824 protected void op(final OptimisticOperation oo) { 3825 assert !(binaryNode.getType().isObject() && oo.isOptimistic); 3826 method.add(oo.getProgramPoint()); 3827 } 3828 }.store(); 3829 } 3830 3831 private void loadASSIGN_BIT_AND(final BinaryNode binaryNode) { 3832 new BinarySelfAssignment(binaryNode) { 3833 @Override 3834 protected void op() { 3835 method.and(); 3836 } 3837 }.store(); 3838 } 3839 3840 private void loadASSIGN_BIT_OR(final BinaryNode binaryNode) { 3841 new BinarySelfAssignment(binaryNode) { 3842 @Override 3843 protected void op() { 3844 method.or(); 3845 } 3846 }.store(); 3847 } 3848 3849 private void loadASSIGN_BIT_XOR(final BinaryNode binaryNode) { 3850 new BinarySelfAssignment(binaryNode) { 3851 @Override 3852 protected void op() { 3853 method.xor(); 3854 } 3855 }.store(); 3856 } 3857 3858 private void loadASSIGN_DIV(final BinaryNode binaryNode) { 3859 new BinaryOptimisticSelfAssignment(binaryNode) { 3860 @Override 3861 protected void op(final OptimisticOperation oo) { 3862 method.div(oo.getProgramPoint()); 3863 } 3864 }.store(); 3865 } 3866 3867 private void loadASSIGN_MOD(final BinaryNode binaryNode) { 3868 new BinaryOptimisticSelfAssignment(binaryNode) { 3869 @Override 3870 protected void op(final OptimisticOperation oo) { 3871 method.rem(oo.getProgramPoint()); 3872 } 3873 }.store(); 3874 } 3875 3876 private void loadASSIGN_MUL(final BinaryNode binaryNode) { 3877 new BinaryOptimisticSelfAssignment(binaryNode) { 3878 @Override 3879 protected void op(final OptimisticOperation oo) { 3880 method.mul(oo.getProgramPoint()); 3881 } 3882 }.store(); 3883 } 3884 3885 private void loadASSIGN_SAR(final BinaryNode binaryNode) { 3886 new BinarySelfAssignment(binaryNode) { 3887 @Override 3888 protected void op() { 3889 method.sar(); 3890 } 3891 }.store(); 3892 } 3893 3894 private void loadASSIGN_SHL(final BinaryNode binaryNode) { 3895 new BinarySelfAssignment(binaryNode) { 3896 @Override 3897 protected void op() { 3898 method.shl(); 3899 } 3900 }.store(); 3901 } 3902 3903 private void loadASSIGN_SHR(final BinaryNode binaryNode) { 3904 new BinarySelfAssignment(binaryNode) { 3905 @Override 3906 protected void op() { 3907 doSHR(); 3908 } 3909 3910 }.store(); 3911 } 3912 3913 private void doSHR() { 3914 // TODO: make SHR optimistic 3915 method.shr().convert(Type.LONG).load(JSType.MAX_UINT).and(); 3916 } 3917 3918 private void loadASSIGN_SUB(final BinaryNode binaryNode) { 3919 new BinaryOptimisticSelfAssignment(binaryNode) { 3920 @Override 3921 protected void op(final OptimisticOperation oo) { 3922 method.sub(oo.getProgramPoint()); 3923 } 3924 }.store(); 3925 } 3926 3927 /** 3928 * Helper class for binary arithmetic ops 3929 */ 3930 private abstract class BinaryArith { 3931 protected abstract void op(int programPoint); 3932 3933 protected void evaluate(final BinaryNode node, final TypeBounds resultBounds) { 3934 final TypeBounds numericBounds = resultBounds.booleanToInt().objectToNumber(); 3935 new OptimisticOperation(node, numericBounds) { 3936 @Override 3937 void loadStack() { 3938 final TypeBounds operandBounds; 3939 if(numericBounds.narrowest == Type.NUMBER) { 3940 // Result should be double always. Propagate it into the operands so we don't have lots of I2D 3941 // and L2D after operand evaluation. 3942 assert numericBounds.widest == Type.NUMBER; 3943 operandBounds = numericBounds; 3944 } else { 3945 final boolean isOptimistic = isValid(getProgramPoint()); 3946 if(isOptimistic) { 3947 operandBounds = new TypeBounds(node.getType(), Type.NUMBER); 3948 } else if(node.isTokenType(TokenType.DIV) || node.isTokenType(TokenType.MOD)) { 3949 // Non-optimistic division must always take double arguments as its result must also be 3950 // double. 3951 operandBounds = TypeBounds.NUMBER; 3952 } else { 3953 // Non-optimistic, non-FP subtraction or multiplication. Allow them to overflow. 3954 operandBounds = new TypeBounds(Type.narrowest(node.getWidestOperandType(), 3955 numericBounds.widest), Type.NUMBER); 3956 } 3957 } 3958 loadBinaryOperands(node.lhs(), node.rhs(), operandBounds, false); 3959 } 3960 3961 @Override 3962 void consumeStack() { 3963 op(getProgramPoint()); 3964 } 3965 }.emit(); 3966 } 3967 } 3968 3969 private void loadBIT_AND(final BinaryNode binaryNode) { 3970 loadBinaryOperands(binaryNode); 3971 method.and(); 3972 } 3973 3974 private void loadBIT_OR(final BinaryNode binaryNode) { 3975 loadBinaryOperands(binaryNode); 3976 method.or(); 3977 } 3978 3979 private void loadBIT_XOR(final BinaryNode binaryNode) { 3980 loadBinaryOperands(binaryNode); 3981 method.xor(); 3982 } 3983 3984 private void loadCOMMARIGHT(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3985 loadAndDiscard(binaryNode.lhs()); 3986 loadExpression(binaryNode.rhs(), resultBounds); 3987 } 3988 3989 private void loadCOMMALEFT(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3990 loadExpression(binaryNode.lhs(), resultBounds); 3991 loadAndDiscard(binaryNode.rhs()); 3992 } 3993 3994 private void loadDIV(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3995 new BinaryArith() { 3996 @Override 3997 protected void op(final int programPoint) { 3998 method.div(programPoint); 3999 } 4000 }.evaluate(binaryNode, resultBounds); 4001 } 4002 4003 private void loadCmp(final BinaryNode binaryNode, final Condition cond) { 4004 assert comparisonOperandsArePrimitive(binaryNode) : binaryNode; 4005 loadBinaryOperands(binaryNode); 4006 4007 final Label trueLabel = new Label("trueLabel"); 4008 final Label afterLabel = new Label("skip"); 4009 4010 method.conditionalJump(cond, trueLabel); 4011 4012 method.load(Boolean.FALSE); 4013 method._goto(afterLabel); 4014 method.label(trueLabel); 4015 method.load(Boolean.TRUE); 4016 method.label(afterLabel); 4017 } 4018 4019 private static boolean comparisonOperandsArePrimitive(final BinaryNode binaryNode) { 4020 final Type widest = Type.widest(binaryNode.lhs().getType(), binaryNode.rhs().getType()); 4021 return widest.isNumeric() || widest.isBoolean(); 4022 } 4023 4024 private void loadMOD(final BinaryNode binaryNode, final TypeBounds resultBounds) { 4025 new BinaryArith() { 4026 @Override 4027 protected void op(final int programPoint) { 4028 method.rem(programPoint); 4029 } 4030 }.evaluate(binaryNode, resultBounds); 4031 } 4032 4033 private void loadMUL(final BinaryNode binaryNode, final TypeBounds resultBounds) { 4034 new BinaryArith() { 4035 @Override 4036 protected void op(final int programPoint) { 4037 method.mul(programPoint); 4038 } 4039 }.evaluate(binaryNode, resultBounds); 4040 } 4041 4042 private void loadSAR(final BinaryNode binaryNode) { 4043 loadBinaryOperands(binaryNode); 4044 method.sar(); 4045 } 4046 4047 private void loadSHL(final BinaryNode binaryNode) { 4048 loadBinaryOperands(binaryNode); 4049 method.shl(); 4050 } 4051 4052 private void loadSHR(final BinaryNode binaryNode) { 4053 loadBinaryOperands(binaryNode); 4054 doSHR(); 4055 } 4056 4057 private void loadSUB(final BinaryNode binaryNode, final TypeBounds resultBounds) { 4058 new BinaryArith() { 4059 @Override 4060 protected void op(final int programPoint) { 4061 method.sub(programPoint); 4062 } 4063 }.evaluate(binaryNode, resultBounds); 4064 } 4065 4066 @Override 4067 public boolean enterLabelNode(final LabelNode labelNode) { 4068 labeledBlockBreakLiveLocals.push(lc.getUsedSlotCount()); 4069 return true; 4070 } 4071 4072 @Override 4073 protected boolean enterDefault(final Node node) { 4074 throw new AssertionError("Code generator entered node of type " + node.getClass().getName()); 4075 } 4076 4077 private void loadTernaryNode(final TernaryNode ternaryNode, final TypeBounds resultBounds) { 4078 final Expression test = ternaryNode.getTest(); 4079 final JoinPredecessorExpression trueExpr = ternaryNode.getTrueExpression(); 4080 final JoinPredecessorExpression falseExpr = ternaryNode.getFalseExpression(); 4081 4082 final Label falseLabel = new Label("ternary_false"); 4083 final Label exitLabel = new Label("ternary_exit"); 4084 4085 final Type outNarrowest = Type.narrowest(resultBounds.widest, Type.generic(Type.widestReturnType(trueExpr.getType(), falseExpr.getType()))); 4086 final TypeBounds outBounds = resultBounds.notNarrowerThan(outNarrowest); 4087 4088 emitBranch(test, falseLabel, false); 4089 4090 loadExpression(trueExpr.getExpression(), outBounds); 4091 assert Type.generic(method.peekType()) == outBounds.narrowest; 4092 method.beforeJoinPoint(trueExpr); 4093 method._goto(exitLabel); 4094 method.label(falseLabel); 4095 loadExpression(falseExpr.getExpression(), outBounds); 4096 assert Type.generic(method.peekType()) == outBounds.narrowest; 4097 method.beforeJoinPoint(falseExpr); 4098 method.label(exitLabel); 4099 } 4100 4101 /** 4102 * Generate all shared scope calls generated during codegen. 4103 */ 4104 void generateScopeCalls() { 4105 for (final SharedScopeCall scopeAccess : lc.getScopeCalls()) { 4106 scopeAccess.generateScopeCall(); 4107 } 4108 } 4109 4110 /** 4111 * Debug code used to print symbols 4112 * 4113 * @param block the block we are in 4114 * @param ident identifier for block or function where applicable 4115 */ 4116 private void printSymbols(final Block block, final String ident) { 4117 if (!compiler.getScriptEnvironment()._print_symbols) { 4118 return; 4119 } 4120 4121 final PrintWriter out = compiler.getScriptEnvironment().getErr(); 4122 out.println("[BLOCK in '" + ident + "']"); 4123 if (!block.printSymbols(out)) { 4124 out.println("<no symbols>"); 4125 } 4126 out.println(); 4127 } 4128 4129 4130 /** 4131 * The difference between a store and a self modifying store is that 4132 * the latter may load part of the target on the stack, e.g. the base 4133 * of an AccessNode or the base and index of an IndexNode. These are used 4134 * both as target and as an extra source. Previously it was problematic 4135 * for self modifying stores if the target/lhs didn't belong to one 4136 * of three trivial categories: IdentNode, AcessNodes, IndexNodes. In that 4137 * case it was evaluated and tagged as "resolved", which meant at the second 4138 * time the lhs of this store was read (e.g. in a = a (second) + b for a += b, 4139 * it would be evaluated to a nop in the scope and cause stack underflow 4140 * 4141 * see NASHORN-703 4142 * 4143 * @param <T> 4144 */ 4145 private abstract class SelfModifyingStore<T extends Expression> extends Store<T> { 4146 protected SelfModifyingStore(final T assignNode, final Expression target) { 4147 super(assignNode, target); 4148 } 4149 4150 @Override 4151 protected boolean isSelfModifying() { 4152 return true; 4153 } 4154 } 4155 4156 /** 4157 * Helper class to generate stores 4158 */ 4159 private abstract class Store<T extends Expression> { 4160 4161 /** An assignment node, e.g. x += y */ 4162 protected final T assignNode; 4163 4164 /** The target node to store to, e.g. x */ 4165 private final Expression target; 4166 4167 /** How deep on the stack do the arguments go if this generates an indy call */ 4168 private int depth; 4169 4170 /** If we have too many arguments, we need temporary storage, this is stored in 'quick' */ 4171 private IdentNode quick; 4172 4173 /** 4174 * Constructor 4175 * 4176 * @param assignNode the node representing the whole assignment 4177 * @param target the target node of the assignment (destination) 4178 */ 4179 protected Store(final T assignNode, final Expression target) { 4180 this.assignNode = assignNode; 4181 this.target = target; 4182 } 4183 4184 /** 4185 * Constructor 4186 * 4187 * @param assignNode the node representing the whole assignment 4188 */ 4189 protected Store(final T assignNode) { 4190 this(assignNode, assignNode); 4191 } 4192 4193 /** 4194 * Is this a self modifying store operation, e.g. *= or ++ 4195 * @return true if self modifying store 4196 */ 4197 protected boolean isSelfModifying() { 4198 return false; 4199 } 4200 4201 private void prologue() { 4202 /** 4203 * This loads the parts of the target, e.g base and index. they are kept 4204 * on the stack throughout the store and used at the end to execute it 4205 */ 4206 4207 target.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 4208 @Override 4209 public boolean enterIdentNode(final IdentNode node) { 4210 if (node.getSymbol().isScope()) { 4211 method.loadCompilerConstant(SCOPE); 4212 depth += Type.SCOPE.getSlots(); 4213 assert depth == 1; 4214 } 4215 return false; 4216 } 4217 4218 private void enterBaseNode() { 4219 assert target instanceof BaseNode : "error - base node " + target + " must be instanceof BaseNode"; 4220 final BaseNode baseNode = (BaseNode)target; 4221 final Expression base = baseNode.getBase(); 4222 4223 loadExpressionAsObject(base); 4224 depth += Type.OBJECT.getSlots(); 4225 assert depth == 1; 4226 4227 if (isSelfModifying()) { 4228 method.dup(); 4229 } 4230 } 4231 4232 @Override 4233 public boolean enterAccessNode(final AccessNode node) { 4234 enterBaseNode(); 4235 return false; 4236 } 4237 4238 @Override 4239 public boolean enterIndexNode(final IndexNode node) { 4240 enterBaseNode(); 4241 4242 final Expression index = node.getIndex(); 4243 if (!index.getType().isNumeric()) { 4244 // could be boolean here as well 4245 loadExpressionAsObject(index); 4246 } else { 4247 loadExpressionUnbounded(index); 4248 } 4249 depth += index.getType().getSlots(); 4250 4251 if (isSelfModifying()) { 4252 //convert "base base index" to "base index base index" 4253 method.dup(1); 4254 } 4255 4256 return false; 4257 } 4258 4259 }); 4260 } 4261 4262 /** 4263 * Generates an extra local variable, always using the same slot, one that is available after the end of the 4264 * frame. 4265 * 4266 * @param type the type of the variable 4267 * 4268 * @return the quick variable 4269 */ 4270 private IdentNode quickLocalVariable(final Type type) { 4271 final String name = lc.getCurrentFunction().uniqueName(QUICK_PREFIX.symbolName()); 4272 final Symbol symbol = new Symbol(name, IS_INTERNAL | HAS_SLOT); 4273 symbol.setHasSlotFor(type); 4274 symbol.setFirstSlot(lc.quickSlot(type)); 4275 4276 final IdentNode quickIdent = IdentNode.createInternalIdentifier(symbol).setType(type); 4277 4278 return quickIdent; 4279 } 4280 4281 // store the result that "lives on" after the op, e.g. "i" in i++ postfix. 4282 protected void storeNonDiscard() { 4283 if (lc.getCurrentDiscard() == assignNode) { 4284 assert assignNode.isAssignment(); 4285 lc.popDiscard(); 4286 return; 4287 } 4288 4289 if (method.dup(depth) == null) { 4290 method.dup(); 4291 final Type quickType = method.peekType(); 4292 this.quick = quickLocalVariable(quickType); 4293 final Symbol quickSymbol = quick.getSymbol(); 4294 method.storeTemp(quickType, quickSymbol.getFirstSlot()); 4295 } 4296 } 4297 4298 private void epilogue() { 4299 /** 4300 * Take the original target args from the stack and use them 4301 * together with the value to be stored to emit the store code 4302 * 4303 * The case that targetSymbol is in scope (!hasSlot) and we actually 4304 * need to do a conversion on non-equivalent types exists, but is 4305 * very rare. See for example test/script/basic/access-specializer.js 4306 */ 4307 target.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 4308 @Override 4309 protected boolean enterDefault(final Node node) { 4310 throw new AssertionError("Unexpected node " + node + " in store epilogue"); 4311 } 4312 4313 @Override 4314 public boolean enterIdentNode(final IdentNode node) { 4315 final Symbol symbol = node.getSymbol(); 4316 assert symbol != null; 4317 if (symbol.isScope()) { 4318 final int flags = CALLSITE_SCOPE | getCallSiteFlags(); 4319 if (isFastScope(symbol)) { 4320 storeFastScopeVar(symbol, flags); 4321 } else { 4322 method.dynamicSet(node.getName(), flags); 4323 } 4324 } else { 4325 final Type storeType = assignNode.getType(); 4326 method.convert(storeType); 4327 storeIdentWithCatchConversion(node, storeType); 4328 } 4329 return false; 4330 4331 } 4332 4333 @Override 4334 public boolean enterAccessNode(final AccessNode node) { 4335 method.dynamicSet(node.getProperty(), getCallSiteFlags()); 4336 return false; 4337 } 4338 4339 @Override 4340 public boolean enterIndexNode(final IndexNode node) { 4341 method.dynamicSetIndex(getCallSiteFlags()); 4342 return false; 4343 } 4344 }); 4345 4346 4347 // whatever is on the stack now is the final answer 4348 } 4349 4350 protected abstract void evaluate(); 4351 4352 void store() { 4353 prologue(); 4354 evaluate(); // leaves an operation of whatever the operationType was on the stack 4355 storeNonDiscard(); 4356 epilogue(); 4357 if (quick != null) { 4358 method.load(quick); 4359 } 4360 } 4361 } 4362 4363 private void newFunctionObject(final FunctionNode functionNode, final boolean addInitializer) { 4364 assert lc.peek() == functionNode; 4365 4366 final int fnId = functionNode.getId(); 4367 4368 final RecompilableScriptFunctionData data = compiler.getScriptFunctionData(fnId); 4369 4370 assert data != null : functionNode.getName() + " has no data"; 4371 4372 if (functionNode.isProgram() && !compiler.isOnDemandCompilation()) { 4373 final CompileUnit fnUnit = functionNode.getCompileUnit(); 4374 final MethodEmitter createFunction = fnUnit.getClassEmitter().method( 4375 EnumSet.of(Flag.PUBLIC, Flag.STATIC), CREATE_PROGRAM_FUNCTION.symbolName(), 4376 ScriptFunction.class, ScriptObject.class); 4377 createFunction.begin(); 4378 createFunction._new(SCRIPTFUNCTION_IMPL_NAME, SCRIPTFUNCTION_IMPL_TYPE).dup(); 4379 loadConstant(data, fnUnit, createFunction); 4380 createFunction.load(SCOPE_TYPE, 0); 4381 createFunction.invoke(constructorNoLookup(SCRIPTFUNCTION_IMPL_NAME, RecompilableScriptFunctionData.class, ScriptObject.class)); 4382 createFunction._return(); 4383 createFunction.end(); 4384 } 4385 4386 if (addInitializer && !initializedFunctionIds.contains(fnId) && !compiler.isOnDemandCompilation()) { 4387 functionNode.getCompileUnit().addFunctionInitializer(data, functionNode); 4388 initializedFunctionIds.add(fnId); 4389 } 4390 4391 // We don't emit a ScriptFunction on stack for the outermost compiled function (as there's no code being 4392 // generated in its outer context that'd need it as a callee). 4393 if (lc.getOutermostFunction() == functionNode) { 4394 return; 4395 } 4396 4397 method._new(SCRIPTFUNCTION_IMPL_NAME, SCRIPTFUNCTION_IMPL_TYPE).dup(); 4398 loadConstant(data); 4399 4400 if (functionNode.needsParentScope()) { 4401 method.loadCompilerConstant(SCOPE); 4402 } else { 4403 method.loadNull(); 4404 } 4405 method.invoke(constructorNoLookup(SCRIPTFUNCTION_IMPL_NAME, RecompilableScriptFunctionData.class, ScriptObject.class)); 4406 } 4407 4408 // calls on Global class. 4409 private MethodEmitter globalInstance() { 4410 return method.invokestatic(GLOBAL_OBJECT, "instance", "()L" + GLOBAL_OBJECT + ';'); 4411 } 4412 4413 private MethodEmitter globalAllocateArguments() { 4414 return method.invokestatic(GLOBAL_OBJECT, "allocateArguments", methodDescriptor(ScriptObject.class, Object[].class, Object.class, int.class)); 4415 } 4416 4417 private MethodEmitter globalNewRegExp() { 4418 return method.invokestatic(GLOBAL_OBJECT, "newRegExp", methodDescriptor(Object.class, String.class, String.class)); 4419 } 4420 4421 private MethodEmitter globalRegExpCopy() { 4422 return method.invokestatic(GLOBAL_OBJECT, "regExpCopy", methodDescriptor(Object.class, Object.class)); 4423 } 4424 4425 private MethodEmitter globalAllocateArray(final ArrayType type) { 4426 //make sure the native array is treated as an array type 4427 return method.invokestatic(GLOBAL_OBJECT, "allocate", "(" + type.getDescriptor() + ")Ljdk/nashorn/internal/objects/NativeArray;"); 4428 } 4429 4430 private MethodEmitter globalIsEval() { 4431 return method.invokestatic(GLOBAL_OBJECT, "isEval", methodDescriptor(boolean.class, Object.class)); 4432 } 4433 4434 private MethodEmitter globalReplaceLocationPropertyPlaceholder() { 4435 return method.invokestatic(GLOBAL_OBJECT, "replaceLocationPropertyPlaceholder", methodDescriptor(Object.class, Object.class, Object.class)); 4436 } 4437 4438 private MethodEmitter globalCheckObjectCoercible() { 4439 return method.invokestatic(GLOBAL_OBJECT, "checkObjectCoercible", methodDescriptor(void.class, Object.class)); 4440 } 4441 4442 private MethodEmitter globalDirectEval() { 4443 return method.invokestatic(GLOBAL_OBJECT, "directEval", 4444 methodDescriptor(Object.class, Object.class, Object.class, Object.class, Object.class, boolean.class)); 4445 } 4446 4447 private abstract class OptimisticOperation { 4448 private final boolean isOptimistic; 4449 // expression and optimistic are the same reference 4450 private final Expression expression; 4451 private final Optimistic optimistic; 4452 private final TypeBounds resultBounds; 4453 4454 OptimisticOperation(final Optimistic optimistic, final TypeBounds resultBounds) { 4455 this.optimistic = optimistic; 4456 this.expression = (Expression)optimistic; 4457 this.resultBounds = resultBounds; 4458 this.isOptimistic = isOptimistic(optimistic) && useOptimisticTypes() && 4459 // Operation is only effectively optimistic if its type, after being coerced into the result bounds 4460 // is narrower than the upper bound. 4461 resultBounds.within(Type.generic(((Expression)optimistic).getType())).narrowerThan(resultBounds.widest); 4462 } 4463 4464 MethodEmitter emit() { 4465 return emit(0); 4466 } 4467 4468 MethodEmitter emit(final int ignoredArgCount) { 4469 final int programPoint = optimistic.getProgramPoint(); 4470 final boolean optimisticOrContinuation = isOptimistic || isContinuationEntryPoint(programPoint); 4471 final boolean currentContinuationEntryPoint = isCurrentContinuationEntryPoint(programPoint); 4472 final int stackSizeOnEntry = method.getStackSize() - ignoredArgCount; 4473 4474 // First store the values on the stack opportunistically into local variables. Doing it before loadStack() 4475 // allows us to not have to pop/load any arguments that are pushed onto it by loadStack() in the second 4476 // storeStack(). 4477 storeStack(ignoredArgCount, optimisticOrContinuation); 4478 4479 // Now, load the stack 4480 loadStack(); 4481 4482 // Now store the values on the stack ultimately into local variables. In vast majority of cases, this is 4483 // (aside from creating the local types map) a no-op, as the first opportunistic stack store will already 4484 // store all variables. However, there can be operations in the loadStack() that invalidate some of the 4485 // stack stores, e.g. in "x[i] = x[++i]", "++i" will invalidate the already stored value for "i". In such 4486 // unfortunate cases this second storeStack() will restore the invariant that everything on the stack is 4487 // stored into a local variable, although at the cost of doing a store/load on the loaded arguments as well. 4488 final int liveLocalsCount = storeStack(method.getStackSize() - stackSizeOnEntry, optimisticOrContinuation); 4489 assert optimisticOrContinuation == (liveLocalsCount != -1); 4490 4491 final Label beginTry; 4492 final Label catchLabel; 4493 final Label afterConsumeStack = isOptimistic || currentContinuationEntryPoint ? new Label("after_consume_stack") : null; 4494 if(isOptimistic) { 4495 beginTry = new Label("try_optimistic"); 4496 final String catchLabelName = (afterConsumeStack == null ? "" : afterConsumeStack.toString()) + "_handler"; 4497 catchLabel = new Label(catchLabelName); 4498 method.label(beginTry); 4499 } else { 4500 beginTry = catchLabel = null; 4501 } 4502 4503 consumeStack(); 4504 4505 if(isOptimistic) { 4506 method._try(beginTry, afterConsumeStack, catchLabel, UnwarrantedOptimismException.class); 4507 } 4508 4509 if(isOptimistic || currentContinuationEntryPoint) { 4510 method.label(afterConsumeStack); 4511 4512 final int[] localLoads = method.getLocalLoadsOnStack(0, stackSizeOnEntry); 4513 assert everyStackValueIsLocalLoad(localLoads) : Arrays.toString(localLoads) + ", " + stackSizeOnEntry + ", " + ignoredArgCount; 4514 final List<Type> localTypesList = method.getLocalVariableTypes(); 4515 final int usedLocals = method.getUsedSlotsWithLiveTemporaries(); 4516 final List<Type> localTypes = method.getWidestLiveLocals(localTypesList.subList(0, usedLocals)); 4517 assert everyLocalLoadIsValid(localLoads, usedLocals) : Arrays.toString(localLoads) + " ~ " + localTypes; 4518 4519 if(isOptimistic) { 4520 addUnwarrantedOptimismHandlerLabel(localTypes, catchLabel); 4521 } 4522 if(currentContinuationEntryPoint) { 4523 final ContinuationInfo ci = getContinuationInfo(); 4524 assert ci != null : "no continuation info found for " + lc.getCurrentFunction(); 4525 assert !ci.hasTargetLabel(); // No duplicate program points 4526 ci.setTargetLabel(afterConsumeStack); 4527 ci.getHandlerLabel().markAsOptimisticContinuationHandlerFor(afterConsumeStack); 4528 // Can't rely on targetLabel.stack.localVariableTypes.length, as it can be higher due to effectively 4529 // dead local variables. 4530 ci.lvarCount = localTypes.size(); 4531 ci.setStackStoreSpec(localLoads); 4532 ci.setStackTypes(Arrays.copyOf(method.getTypesFromStack(method.getStackSize()), stackSizeOnEntry)); 4533 assert ci.getStackStoreSpec().length == ci.getStackTypes().length; 4534 ci.setReturnValueType(method.peekType()); 4535 ci.lineNumber = getLastLineNumber(); 4536 ci.catchLabel = catchLabels.peek(); 4537 } 4538 } 4539 return method; 4540 } 4541 4542 /** 4543 * Stores the current contents of the stack into local variables so they are not lost before invoking something that 4544 * can result in an {@code UnwarantedOptimizationException}. 4545 * @param ignoreArgCount the number of topmost arguments on stack to ignore when deciding on the shape of the catch 4546 * block. Those are used in the situations when we could not place the call to {@code storeStack} early enough 4547 * (before emitting code for pushing the arguments that the optimistic call will pop). This is admittedly a 4548 * deficiency in the design of the code generator when it deals with self-assignments and we should probably look 4549 * into fixing it. 4550 * @return types of the significant local variables after the stack was stored (types for local variables used 4551 * for temporary storage of ignored arguments are not returned). 4552 * @param optimisticOrContinuation if false, this method should not execute 4553 * a label for a catch block for the {@code UnwarantedOptimizationException}, suitable for capturing the 4554 * currently live local variables, tailored to their types. 4555 */ 4556 private int storeStack(final int ignoreArgCount, final boolean optimisticOrContinuation) { 4557 if(!optimisticOrContinuation) { 4558 return -1; // NOTE: correct value to return is lc.getUsedSlotCount(), but it wouldn't be used anyway 4559 } 4560 4561 final int stackSize = method.getStackSize(); 4562 final Type[] stackTypes = method.getTypesFromStack(stackSize); 4563 final int[] localLoadsOnStack = method.getLocalLoadsOnStack(0, stackSize); 4564 final int usedSlots = method.getUsedSlotsWithLiveTemporaries(); 4565 4566 final int firstIgnored = stackSize - ignoreArgCount; 4567 // Find the first value on the stack (from the bottom) that is not a load from a local variable. 4568 int firstNonLoad = 0; 4569 while(firstNonLoad < firstIgnored && localLoadsOnStack[firstNonLoad] != Label.Stack.NON_LOAD) { 4570 firstNonLoad++; 4571 } 4572 4573 // Only do the store/load if first non-load is not an ignored argument. Otherwise, do nothing and return 4574 // the number of used slots as the number of live local variables. 4575 if(firstNonLoad >= firstIgnored) { 4576 return usedSlots; 4577 } 4578 4579 // Find the number of new temporary local variables that we need; it's the number of values on the stack that 4580 // are not direct loads of existing local variables. 4581 int tempSlotsNeeded = 0; 4582 for(int i = firstNonLoad; i < stackSize; ++i) { 4583 if(localLoadsOnStack[i] == Label.Stack.NON_LOAD) { 4584 tempSlotsNeeded += stackTypes[i].getSlots(); 4585 } 4586 } 4587 4588 // Ensure all values on the stack that weren't directly loaded from a local variable are stored in a local 4589 // variable. We're starting from highest local variable index, so that in case ignoreArgCount > 0 the ignored 4590 // ones end up at the end of the local variable table. 4591 int lastTempSlot = usedSlots + tempSlotsNeeded; 4592 int ignoreSlotCount = 0; 4593 for(int i = stackSize; i -- > firstNonLoad;) { 4594 final int loadSlot = localLoadsOnStack[i]; 4595 if(loadSlot == Label.Stack.NON_LOAD) { 4596 final Type type = stackTypes[i]; 4597 final int slots = type.getSlots(); 4598 lastTempSlot -= slots; 4599 if(i >= firstIgnored) { 4600 ignoreSlotCount += slots; 4601 } 4602 method.storeTemp(type, lastTempSlot); 4603 } else { 4604 method.pop(); 4605 } 4606 } 4607 assert lastTempSlot == usedSlots; // used all temporary locals 4608 4609 final List<Type> localTypesList = method.getLocalVariableTypes(); 4610 4611 // Load values back on stack. 4612 for(int i = firstNonLoad; i < stackSize; ++i) { 4613 final int loadSlot = localLoadsOnStack[i]; 4614 final Type stackType = stackTypes[i]; 4615 final boolean isLoad = loadSlot != Label.Stack.NON_LOAD; 4616 final int lvarSlot = isLoad ? loadSlot : lastTempSlot; 4617 final Type lvarType = localTypesList.get(lvarSlot); 4618 method.load(lvarType, lvarSlot); 4619 if(isLoad) { 4620 // Conversion operators (I2L etc.) preserve "load"-ness of the value despite the fact that, in the 4621 // strict sense they are creating a derived value from the loaded value. This special behavior of 4622 // on-stack conversion operators is necessary to accommodate for differences in local variable types 4623 // after deoptimization; having a conversion operator throw away "load"-ness would create different 4624 // local variable table shapes between optimism-failed code and its deoptimized rest-of method). 4625 // After we load the value back, we need to redo the conversion to the stack type if stack type is 4626 // different. 4627 // NOTE: this would only strictly be necessary for widening conversions (I2L, L2D, I2D), and not for 4628 // narrowing ones (L2I, D2L, D2I) as only widening conversions are the ones that can get eliminated 4629 // in a deoptimized method, as their original input argument got widened. Maybe experiment with 4630 // throwing away "load"-ness for narrowing conversions in MethodEmitter.convert()? 4631 method.convert(stackType); 4632 } else { 4633 // temporary stores never needs a convert, as their type is always the same as the stack type. 4634 assert lvarType == stackType; 4635 lastTempSlot += lvarType.getSlots(); 4636 } 4637 } 4638 // used all temporaries 4639 assert lastTempSlot == usedSlots + tempSlotsNeeded; 4640 4641 return lastTempSlot - ignoreSlotCount; 4642 } 4643 4644 private void addUnwarrantedOptimismHandlerLabel(final List<Type> localTypes, final Label label) { 4645 final String lvarTypesDescriptor = getLvarTypesDescriptor(localTypes); 4646 final Map<String, Collection<Label>> unwarrantedOptimismHandlers = lc.getUnwarrantedOptimismHandlers(); 4647 Collection<Label> labels = unwarrantedOptimismHandlers.get(lvarTypesDescriptor); 4648 if(labels == null) { 4649 labels = new LinkedList<>(); 4650 unwarrantedOptimismHandlers.put(lvarTypesDescriptor, labels); 4651 } 4652 method.markLabelAsOptimisticCatchHandler(label, localTypes.size()); 4653 labels.add(label); 4654 } 4655 4656 abstract void loadStack(); 4657 4658 // Make sure that whatever indy call site you emit from this method uses {@code getCallSiteFlagsOptimistic(node)} 4659 // or otherwise ensure optimistic flag is correctly set in the call site, otherwise it doesn't make much sense 4660 // to use OptimisticExpression for emitting it. 4661 abstract void consumeStack(); 4662 4663 /** 4664 * Emits the correct dynamic getter code. Normally just delegates to method emitter, except when the target 4665 * expression is optimistic, and the desired type is narrower than the optimistic type. In that case, it'll emit a 4666 * dynamic getter with its original optimistic type, and explicitly insert a narrowing conversion. This way we can 4667 * preserve the optimism of the values even if they're subsequently immediately coerced into a narrower type. This 4668 * is beneficial because in this case we can still presume that since the original getter was optimistic, the 4669 * conversion has no side effects. 4670 * @param name the name of the property being get 4671 * @param flags call site flags 4672 * @param isMethod whether we're preferrably retrieving a function 4673 * @return the current method emitter 4674 */ 4675 MethodEmitter dynamicGet(final String name, final int flags, final boolean isMethod) { 4676 if(isOptimistic) { 4677 return method.dynamicGet(getOptimisticCoercedType(), name, getOptimisticFlags(flags), isMethod); 4678 } 4679 return method.dynamicGet(resultBounds.within(expression.getType()), name, nonOptimisticFlags(flags), isMethod); 4680 } 4681 4682 MethodEmitter dynamicGetIndex(final int flags, final boolean isMethod) { 4683 if(isOptimistic) { 4684 return method.dynamicGetIndex(getOptimisticCoercedType(), getOptimisticFlags(flags), isMethod); 4685 } 4686 return method.dynamicGetIndex(resultBounds.within(expression.getType()), nonOptimisticFlags(flags), isMethod); 4687 } 4688 4689 MethodEmitter dynamicCall(final int argCount, final int flags) { 4690 if (isOptimistic) { 4691 return method.dynamicCall(getOptimisticCoercedType(), argCount, getOptimisticFlags(flags)); 4692 } 4693 return method.dynamicCall(resultBounds.within(expression.getType()), argCount, nonOptimisticFlags(flags)); 4694 } 4695 4696 int getOptimisticFlags(final int flags) { 4697 return flags | CALLSITE_OPTIMISTIC | (optimistic.getProgramPoint() << CALLSITE_PROGRAM_POINT_SHIFT); //encode program point in high bits 4698 } 4699 4700 int getProgramPoint() { 4701 return isOptimistic ? optimistic.getProgramPoint() : INVALID_PROGRAM_POINT; 4702 } 4703 4704 void convertOptimisticReturnValue() { 4705 if (isOptimistic) { 4706 final Type optimisticType = getOptimisticCoercedType(); 4707 if(!optimisticType.isObject()) { 4708 method.load(optimistic.getProgramPoint()); 4709 if(optimisticType.isInteger()) { 4710 method.invoke(ENSURE_INT); 4711 } else if(optimisticType.isLong()) { 4712 method.invoke(ENSURE_LONG); 4713 } else if(optimisticType.isNumber()) { 4714 method.invoke(ENSURE_NUMBER); 4715 } else { 4716 throw new AssertionError(optimisticType); 4717 } 4718 } 4719 } 4720 } 4721 4722 void replaceCompileTimeProperty() { 4723 final IdentNode identNode = (IdentNode)expression; 4724 final String name = identNode.getSymbol().getName(); 4725 if (CompilerConstants.__FILE__.name().equals(name)) { 4726 replaceCompileTimeProperty(getCurrentSource().getName()); 4727 } else if (CompilerConstants.__DIR__.name().equals(name)) { 4728 replaceCompileTimeProperty(getCurrentSource().getBase()); 4729 } else if (CompilerConstants.__LINE__.name().equals(name)) { 4730 replaceCompileTimeProperty(getCurrentSource().getLine(identNode.position())); 4731 } 4732 } 4733 4734 /** 4735 * When an ident with name __FILE__, __DIR__, or __LINE__ is loaded, we'll try to look it up as any other 4736 * identifier. However, if it gets all the way up to the Global object, it will send back a special value that 4737 * represents a placeholder for these compile-time location properties. This method will generate code that loads 4738 * the value of the compile-time location property and then invokes a method in Global that will replace the 4739 * placeholder with the value. Effectively, if the symbol for these properties is defined anywhere in the lexical 4740 * scope, they take precedence, but if they aren't, then they resolve to the compile-time location property. 4741 * @param propertyValue the actual value of the property 4742 */ 4743 private void replaceCompileTimeProperty(final Object propertyValue) { 4744 assert method.peekType().isObject(); 4745 if(propertyValue instanceof String || propertyValue == null) { 4746 method.load((String)propertyValue); 4747 } else if(propertyValue instanceof Integer) { 4748 method.load(((Integer)propertyValue).intValue()); 4749 method.convert(Type.OBJECT); 4750 } else { 4751 throw new AssertionError(); 4752 } 4753 globalReplaceLocationPropertyPlaceholder(); 4754 convertOptimisticReturnValue(); 4755 } 4756 4757 /** 4758 * Returns the type that should be used as the return type of the dynamic invocation that is emitted as the code 4759 * for the current optimistic operation. If the type bounds is exact boolean or narrower than the expression's 4760 * optimistic type, then the optimistic type is returned, otherwise the coercing type. Effectively, this method 4761 * allows for moving the coercion into the optimistic type when it won't adversely affect the optimistic 4762 * evaluation semantics, and for preserving the optimistic type and doing a separate coercion when it would 4763 * affect it. 4764 * @return 4765 */ 4766 private Type getOptimisticCoercedType() { 4767 final Type optimisticType = expression.getType(); 4768 assert resultBounds.widest.widerThan(optimisticType); 4769 final Type narrowest = resultBounds.narrowest; 4770 4771 if(narrowest.isBoolean() || narrowest.narrowerThan(optimisticType)) { 4772 assert !optimisticType.isObject(); 4773 return optimisticType; 4774 } 4775 assert !narrowest.isObject(); 4776 return narrowest; 4777 } 4778 } 4779 4780 private static boolean isOptimistic(final Optimistic optimistic) { 4781 if(!optimistic.canBeOptimistic()) { 4782 return false; 4783 } 4784 final Expression expr = (Expression)optimistic; 4785 return expr.getType().narrowerThan(expr.getWidestOperationType()); 4786 } 4787 4788 private static boolean everyLocalLoadIsValid(final int[] loads, final int localCount) { 4789 for (final int load : loads) { 4790 if(load < 0 || load >= localCount) { 4791 return false; 4792 } 4793 } 4794 return true; 4795 } 4796 4797 private static boolean everyStackValueIsLocalLoad(final int[] loads) { 4798 for (final int load : loads) { 4799 if(load == Label.Stack.NON_LOAD) { 4800 return false; 4801 } 4802 } 4803 return true; 4804 } 4805 4806 private String getLvarTypesDescriptor(final List<Type> localVarTypes) { 4807 final int count = localVarTypes.size(); 4808 final StringBuilder desc = new StringBuilder(count); 4809 for(int i = 0; i < count;) { 4810 i += appendType(desc, localVarTypes.get(i)); 4811 } 4812 return method.markSymbolBoundariesInLvarTypesDescriptor(desc.toString()); 4813 } 4814 4815 private static int appendType(final StringBuilder b, final Type t) { 4816 b.append(t.getBytecodeStackType()); 4817 return t.getSlots(); 4818 } 4819 4820 private static int countSymbolsInLvarTypeDescriptor(final String lvarTypeDescriptor) { 4821 int count = 0; 4822 for(int i = 0; i < lvarTypeDescriptor.length(); ++i) { 4823 if(Character.isUpperCase(lvarTypeDescriptor.charAt(i))) { 4824 ++count; 4825 } 4826 } 4827 return count; 4828 4829 } 4830 /** 4831 * Generates all the required {@code UnwarrantedOptimismException} handlers for the current function. The employed 4832 * strategy strives to maximize code reuse. Every handler constructs an array to hold the local variables, then 4833 * fills in some trailing part of the local variables (those for which it has a unique suffix in the descriptor), 4834 * then jumps to a handler for a prefix that's shared with other handlers. A handler that fills up locals up to 4835 * position 0 will not jump to a prefix handler (as it has no prefix), but instead end with constructing and 4836 * throwing a {@code RewriteException}. Since we lexicographically sort the entries, we only need to check every 4837 * entry to its immediately preceding one for longest matching prefix. 4838 * @return true if there is at least one exception handler 4839 */ 4840 private boolean generateUnwarrantedOptimismExceptionHandlers(final FunctionNode fn) { 4841 if(!useOptimisticTypes()) { 4842 return false; 4843 } 4844 4845 // Take the mapping of lvarSpecs -> labels, and turn them into a descending lexicographically sorted list of 4846 // handler specifications. 4847 final Map<String, Collection<Label>> unwarrantedOptimismHandlers = lc.popUnwarrantedOptimismHandlers(); 4848 if(unwarrantedOptimismHandlers.isEmpty()) { 4849 return false; 4850 } 4851 4852 method.lineNumber(0); 4853 4854 final List<OptimismExceptionHandlerSpec> handlerSpecs = new ArrayList<>(unwarrantedOptimismHandlers.size() * 4/3); 4855 for(final String spec: unwarrantedOptimismHandlers.keySet()) { 4856 handlerSpecs.add(new OptimismExceptionHandlerSpec(spec, true)); 4857 } 4858 Collections.sort(handlerSpecs, Collections.reverseOrder()); 4859 4860 // Map of local variable specifications to labels for populating the array for that local variable spec. 4861 final Map<String, Label> delegationLabels = new HashMap<>(); 4862 4863 // Do everything in a single pass over the handlerSpecs list. Note that the list can actually grow as we're 4864 // passing through it as we might add new prefix handlers into it, so can't hoist size() outside of the loop. 4865 for(int handlerIndex = 0; handlerIndex < handlerSpecs.size(); ++handlerIndex) { 4866 final OptimismExceptionHandlerSpec spec = handlerSpecs.get(handlerIndex); 4867 final String lvarSpec = spec.lvarSpec; 4868 if(spec.catchTarget) { 4869 assert !method.isReachable(); 4870 // Start a catch block and assign the labels for this lvarSpec with it. 4871 method._catch(unwarrantedOptimismHandlers.get(lvarSpec)); 4872 // This spec is a catch target, so emit array creation code. The length of the array is the number of 4873 // symbols - the number of uppercase characters. 4874 method.load(countSymbolsInLvarTypeDescriptor(lvarSpec)); 4875 method.newarray(Type.OBJECT_ARRAY); 4876 } 4877 if(spec.delegationTarget) { 4878 // If another handler can delegate to this handler as its prefix, then put a jump target here for the 4879 // shared code (after the array creation code, which is never shared). 4880 method.label(delegationLabels.get(lvarSpec)); // label must exist 4881 } 4882 4883 final boolean lastHandler = handlerIndex == handlerSpecs.size() - 1; 4884 4885 int lvarIndex; 4886 final int firstArrayIndex; 4887 final int firstLvarIndex; 4888 Label delegationLabel; 4889 final String commonLvarSpec; 4890 if(lastHandler) { 4891 // Last handler block, doesn't delegate to anything. 4892 lvarIndex = 0; 4893 firstLvarIndex = 0; 4894 firstArrayIndex = 0; 4895 delegationLabel = null; 4896 commonLvarSpec = null; 4897 } else { 4898 // Not yet the last handler block, will definitely delegate to another handler; let's figure out which 4899 // one. It can be an already declared handler further down the list, or it might need to declare a new 4900 // prefix handler. 4901 4902 // Since we're lexicographically ordered, the common prefix handler is defined by the common prefix of 4903 // this handler and the next handler on the list. 4904 final int nextHandlerIndex = handlerIndex + 1; 4905 final String nextLvarSpec = handlerSpecs.get(nextHandlerIndex).lvarSpec; 4906 commonLvarSpec = commonPrefix(lvarSpec, nextLvarSpec); 4907 // We don't chop symbols in half 4908 assert Character.isUpperCase(commonLvarSpec.charAt(commonLvarSpec.length() - 1)); 4909 4910 // Let's find if we already have a declaration for such handler, or we need to insert it. 4911 { 4912 boolean addNewHandler = true; 4913 int commonHandlerIndex = nextHandlerIndex; 4914 for(; commonHandlerIndex < handlerSpecs.size(); ++commonHandlerIndex) { 4915 final OptimismExceptionHandlerSpec forwardHandlerSpec = handlerSpecs.get(commonHandlerIndex); 4916 final String forwardLvarSpec = forwardHandlerSpec.lvarSpec; 4917 if(forwardLvarSpec.equals(commonLvarSpec)) { 4918 // We already have a handler for the common prefix. 4919 addNewHandler = false; 4920 // Make sure we mark it as a delegation target. 4921 forwardHandlerSpec.delegationTarget = true; 4922 break; 4923 } else if(!forwardLvarSpec.startsWith(commonLvarSpec)) { 4924 break; 4925 } 4926 } 4927 if(addNewHandler) { 4928 // We need to insert a common prefix handler. Note handlers created with catchTarget == false 4929 // will automatically have delegationTarget == true (because that's the only reason for their 4930 // existence). 4931 handlerSpecs.add(commonHandlerIndex, new OptimismExceptionHandlerSpec(commonLvarSpec, false)); 4932 } 4933 } 4934 4935 firstArrayIndex = countSymbolsInLvarTypeDescriptor(commonLvarSpec); 4936 lvarIndex = 0; 4937 for(int j = 0; j < commonLvarSpec.length(); ++j) { 4938 lvarIndex += CodeGeneratorLexicalContext.getTypeForSlotDescriptor(commonLvarSpec.charAt(j)).getSlots(); 4939 } 4940 firstLvarIndex = lvarIndex; 4941 4942 // Create a delegation label if not already present 4943 delegationLabel = delegationLabels.get(commonLvarSpec); 4944 if(delegationLabel == null) { 4945 // uo_pa == "unwarranted optimism, populate array" 4946 delegationLabel = new Label("uo_pa_" + commonLvarSpec); 4947 delegationLabels.put(commonLvarSpec, delegationLabel); 4948 } 4949 } 4950 4951 // Load local variables handled by this handler on stack 4952 int args = 0; 4953 boolean symbolHadValue = false; 4954 for(int typeIndex = commonLvarSpec == null ? 0 : commonLvarSpec.length(); typeIndex < lvarSpec.length(); ++typeIndex) { 4955 final char typeDesc = lvarSpec.charAt(typeIndex); 4956 final Type lvarType = CodeGeneratorLexicalContext.getTypeForSlotDescriptor(typeDesc); 4957 if (!lvarType.isUnknown()) { 4958 method.load(lvarType, lvarIndex); 4959 symbolHadValue = true; 4960 args++; 4961 } else if(typeDesc == 'U' && !symbolHadValue) { 4962 // Symbol boundary with undefined last value. Check if all previous values for this symbol were also 4963 // undefined; if so, emit one explicit Undefined. This serves to ensure that we're emiting exactly 4964 // one value for every symbol that uses local slots. While we could in theory ignore symbols that 4965 // are undefined (in other words, dead) at the point where this exception was thrown, unfortunately 4966 // we can't do it in practice. The reason for this is that currently our liveness analysis is 4967 // coarse (it can determine whether a symbol has not been read with a particular type anywhere in 4968 // the function being compiled, but that's it), and a symbol being promoted to Object due to a 4969 // deoptimization will suddenly show up as "live for Object type", and previously dead U->O 4970 // conversions on loop entries will suddenly become alive in the deoptimized method which will then 4971 // expect a value for that slot in its continuation handler. If we had precise liveness analysis, we 4972 // could go back to excluding known dead symbols from the payload of the RewriteException. 4973 if(method.peekType() == Type.UNDEFINED) { 4974 method.dup(); 4975 } else { 4976 method.loadUndefined(Type.OBJECT); 4977 } 4978 args++; 4979 } 4980 if(Character.isUpperCase(typeDesc)) { 4981 // Reached symbol boundary; reset flag for the next symbol. 4982 symbolHadValue = false; 4983 } 4984 lvarIndex += lvarType.getSlots(); 4985 } 4986 assert args > 0; 4987 // Delegate actual storing into array to an array populator utility method. 4988 //on the stack: 4989 // object array to be populated 4990 // start index 4991 // a lot of types 4992 method.dynamicArrayPopulatorCall(args + 1, firstArrayIndex); 4993 if(delegationLabel != null) { 4994 // We cascade to a prefix handler to fill out the rest of the local variables and throw the 4995 // RewriteException. 4996 assert !lastHandler; 4997 assert commonLvarSpec != null; 4998 // Must undefine the local variables that we have already processed for the sake of correct join on the 4999 // delegate label 5000 method.undefineLocalVariables(firstLvarIndex, true); 5001 final OptimismExceptionHandlerSpec nextSpec = handlerSpecs.get(handlerIndex + 1); 5002 // If the delegate immediately follows, and it's not a catch target (so it doesn't have array setup 5003 // code) don't bother emitting a jump, as we'd just jump to the next instruction. 5004 if(!nextSpec.lvarSpec.equals(commonLvarSpec) || nextSpec.catchTarget) { 5005 method._goto(delegationLabel); 5006 } 5007 } else { 5008 assert lastHandler; 5009 // Nothing to delegate to, so this handler must create and throw the RewriteException. 5010 // At this point we have the UnwarrantedOptimismException and the Object[] with local variables on 5011 // stack. We need to create a RewriteException, push two references to it below the constructor 5012 // arguments, invoke the constructor, and throw the exception. 5013 loadConstant(getByteCodeSymbolNames(fn)); 5014 if (isRestOf()) { 5015 loadConstant(getContinuationEntryPoints()); 5016 method.invoke(CREATE_REWRITE_EXCEPTION_REST_OF); 5017 } else { 5018 method.invoke(CREATE_REWRITE_EXCEPTION); 5019 } 5020 method.athrow(); 5021 } 5022 } 5023 return true; 5024 } 5025 5026 private static String[] getByteCodeSymbolNames(final FunctionNode fn) { 5027 // Only names of local variables on the function level are captured. This information is used to reduce 5028 // deoptimizations, so as much as we can capture will help. We rely on the fact that function wide variables are 5029 // all live all the time, so the array passed to rewrite exception contains one element for every slotted symbol 5030 // here. 5031 final List<String> names = new ArrayList<>(); 5032 for (final Symbol symbol: fn.getBody().getSymbols()) { 5033 if (symbol.hasSlot()) { 5034 if (symbol.isScope()) { 5035 // slot + scope can only be true for parameters 5036 assert symbol.isParam(); 5037 names.add(null); 5038 } else { 5039 names.add(symbol.getName()); 5040 } 5041 } 5042 } 5043 return names.toArray(new String[names.size()]); 5044 } 5045 5046 private static String commonPrefix(final String s1, final String s2) { 5047 final int l1 = s1.length(); 5048 final int l = Math.min(l1, s2.length()); 5049 int lms = -1; // last matching symbol 5050 for(int i = 0; i < l; ++i) { 5051 final char c1 = s1.charAt(i); 5052 if(c1 != s2.charAt(i)) { 5053 return s1.substring(0, lms + 1); 5054 } else if(Character.isUpperCase(c1)) { 5055 lms = i; 5056 } 5057 } 5058 return l == l1 ? s1 : s2; 5059 } 5060 5061 private static class OptimismExceptionHandlerSpec implements Comparable<OptimismExceptionHandlerSpec> { 5062 private final String lvarSpec; 5063 private final boolean catchTarget; 5064 private boolean delegationTarget; 5065 5066 OptimismExceptionHandlerSpec(final String lvarSpec, final boolean catchTarget) { 5067 this.lvarSpec = lvarSpec; 5068 this.catchTarget = catchTarget; 5069 if(!catchTarget) { 5070 delegationTarget = true; 5071 } 5072 } 5073 5074 @Override 5075 public int compareTo(final OptimismExceptionHandlerSpec o) { 5076 return lvarSpec.compareTo(o.lvarSpec); 5077 } 5078 5079 @Override 5080 public String toString() { 5081 final StringBuilder b = new StringBuilder(64).append("[HandlerSpec ").append(lvarSpec); 5082 if(catchTarget) { 5083 b.append(", catchTarget"); 5084 } 5085 if(delegationTarget) { 5086 b.append(", delegationTarget"); 5087 } 5088 return b.append("]").toString(); 5089 } 5090 } 5091 5092 private static class ContinuationInfo { 5093 private final Label handlerLabel; 5094 private Label targetLabel; // Label for the target instruction. 5095 int lvarCount; 5096 // Indices of local variables that need to be loaded on the stack when this node completes 5097 private int[] stackStoreSpec; 5098 // Types of values loaded on the stack 5099 private Type[] stackTypes; 5100 // If non-null, this node should perform the requisite type conversion 5101 private Type returnValueType; 5102 // If we are in the middle of an object literal initialization, we need to update the map 5103 private PropertyMap objectLiteralMap; 5104 // Object literal stack depth for object literal - not necessarly top if property is a tree 5105 private int objectLiteralStackDepth = -1; 5106 // The line number at the continuation point 5107 private int lineNumber; 5108 // The active catch label, in case the continuation point is in a try/catch block 5109 private Label catchLabel; 5110 // The number of scopes that need to be popped before control is transferred to the catch label. 5111 private int exceptionScopePops; 5112 5113 ContinuationInfo() { 5114 this.handlerLabel = new Label("continuation_handler"); 5115 } 5116 5117 Label getHandlerLabel() { 5118 return handlerLabel; 5119 } 5120 5121 boolean hasTargetLabel() { 5122 return targetLabel != null; 5123 } 5124 5125 Label getTargetLabel() { 5126 return targetLabel; 5127 } 5128 5129 void setTargetLabel(final Label targetLabel) { 5130 this.targetLabel = targetLabel; 5131 } 5132 5133 int[] getStackStoreSpec() { 5134 return stackStoreSpec.clone(); 5135 } 5136 5137 void setStackStoreSpec(final int[] stackStoreSpec) { 5138 this.stackStoreSpec = stackStoreSpec; 5139 } 5140 5141 Type[] getStackTypes() { 5142 return stackTypes.clone(); 5143 } 5144 5145 void setStackTypes(final Type[] stackTypes) { 5146 this.stackTypes = stackTypes; 5147 } 5148 5149 Type getReturnValueType() { 5150 return returnValueType; 5151 } 5152 5153 void setReturnValueType(final Type returnValueType) { 5154 this.returnValueType = returnValueType; 5155 } 5156 5157 int getObjectLiteralStackDepth() { 5158 return objectLiteralStackDepth; 5159 } 5160 5161 void setObjectLiteralStackDepth(final int objectLiteralStackDepth) { 5162 this.objectLiteralStackDepth = objectLiteralStackDepth; 5163 } 5164 5165 PropertyMap getObjectLiteralMap() { 5166 return objectLiteralMap; 5167 } 5168 5169 void setObjectLiteralMap(final PropertyMap objectLiteralMap) { 5170 this.objectLiteralMap = objectLiteralMap; 5171 } 5172 5173 @Override 5174 public String toString() { 5175 return "[localVariableTypes=" + targetLabel.getStack().getLocalVariableTypesCopy() + ", stackStoreSpec=" + 5176 Arrays.toString(stackStoreSpec) + ", returnValueType=" + returnValueType + "]"; 5177 } 5178 } 5179 5180 private ContinuationInfo getContinuationInfo() { 5181 return fnIdToContinuationInfo.get(lc.getCurrentFunction().getId()); 5182 } 5183 5184 private void generateContinuationHandler() { 5185 if (!isRestOf()) { 5186 return; 5187 } 5188 5189 final ContinuationInfo ci = getContinuationInfo(); 5190 method.label(ci.getHandlerLabel()); 5191 5192 // There should never be an exception thrown from the continuation handler, but in case there is (meaning, 5193 // Nashorn has a bug), then line number 0 will be an indication of where it came from (line numbers are Uint16). 5194 method.lineNumber(0); 5195 5196 final Label.Stack stack = ci.getTargetLabel().getStack(); 5197 final List<Type> lvarTypes = stack.getLocalVariableTypesCopy(); 5198 final BitSet symbolBoundary = stack.getSymbolBoundaryCopy(); 5199 final int lvarCount = ci.lvarCount; 5200 5201 final Type rewriteExceptionType = Type.typeFor(RewriteException.class); 5202 // Store the RewriteException into an unused local variable slot. 5203 method.load(rewriteExceptionType, 0); 5204 method.storeTemp(rewriteExceptionType, lvarCount); 5205 // Get local variable array 5206 method.load(rewriteExceptionType, 0); 5207 method.invoke(RewriteException.GET_BYTECODE_SLOTS); 5208 // Store local variables. Note that deoptimization might introduce new value types for existing local variables, 5209 // so we must use both liveLocals and symbolBoundary, as in some cases (when the continuation is inside of a try 5210 // block) we need to store the incoming value into multiple slots. The optimism exception handlers will have 5211 // exactly one array element for every symbol that uses bytecode storage. If in the originating method the value 5212 // was undefined, there will be an explicit Undefined value in the array. 5213 int arrayIndex = 0; 5214 for(int lvarIndex = 0; lvarIndex < lvarCount;) { 5215 final Type lvarType = lvarTypes.get(lvarIndex); 5216 if(!lvarType.isUnknown()) { 5217 method.dup(); 5218 method.load(arrayIndex).arrayload(); 5219 final Class<?> typeClass = lvarType.getTypeClass(); 5220 // Deoptimization in array initializers can cause arrays to undergo component type widening 5221 if(typeClass == long[].class) { 5222 method.load(rewriteExceptionType, lvarCount); 5223 method.invoke(RewriteException.TO_LONG_ARRAY); 5224 } else if(typeClass == double[].class) { 5225 method.load(rewriteExceptionType, lvarCount); 5226 method.invoke(RewriteException.TO_DOUBLE_ARRAY); 5227 } else if(typeClass == Object[].class) { 5228 method.load(rewriteExceptionType, lvarCount); 5229 method.invoke(RewriteException.TO_OBJECT_ARRAY); 5230 } else { 5231 if(!(typeClass.isPrimitive() || typeClass == Object.class)) { 5232 // NOTE: this can only happen with dead stores. E.g. for the program "1; []; f();" in which the 5233 // call to f() will deoptimize the call site, but it'll expect :return to have the type 5234 // NativeArray. However, in the more optimal version, :return's only live type is int, therefore 5235 // "{O}:return = []" is a dead store, and the variable will be sent into the continuation as 5236 // Undefined, however NativeArray can't hold Undefined instance. 5237 method.loadType(Type.getInternalName(typeClass)); 5238 method.invoke(RewriteException.INSTANCE_OR_NULL); 5239 } 5240 method.convert(lvarType); 5241 } 5242 method.storeHidden(lvarType, lvarIndex, false); 5243 } 5244 final int nextLvarIndex = lvarIndex + lvarType.getSlots(); 5245 if(symbolBoundary.get(nextLvarIndex - 1)) { 5246 ++arrayIndex; 5247 } 5248 lvarIndex = nextLvarIndex; 5249 } 5250 if(assertsEnabled) { 5251 method.load(arrayIndex); 5252 method.invoke(RewriteException.ASSERT_ARRAY_LENGTH); 5253 } else { 5254 method.pop(); 5255 } 5256 5257 final int[] stackStoreSpec = ci.getStackStoreSpec(); 5258 final Type[] stackTypes = ci.getStackTypes(); 5259 final boolean isStackEmpty = stackStoreSpec.length == 0; 5260 boolean replacedObjectLiteralMap = false; 5261 if(!isStackEmpty) { 5262 // Load arguments on the stack 5263 final int objectLiteralStackDepth = ci.getObjectLiteralStackDepth(); 5264 for(int i = 0; i < stackStoreSpec.length; ++i) { 5265 final int slot = stackStoreSpec[i]; 5266 method.load(lvarTypes.get(slot), slot); 5267 method.convert(stackTypes[i]); 5268 // stack: s0=object literal being initialized 5269 // change map of s0 so that the property we are initilizing when we failed 5270 // is now ci.returnValueType 5271 if (i == objectLiteralStackDepth) { 5272 method.dup(); 5273 assert ci.getObjectLiteralMap() != null; 5274 assert ScriptObject.class.isAssignableFrom(method.peekType().getTypeClass()) : method.peekType().getTypeClass() + " is not a script object"; 5275 loadConstant(ci.getObjectLiteralMap()); 5276 method.invoke(ScriptObject.SET_MAP); 5277 replacedObjectLiteralMap = true; 5278 } 5279 } 5280 } 5281 // Must have emitted the code for replacing the map of an object literal if we have a set object literal stack depth 5282 assert ci.getObjectLiteralStackDepth() == -1 || replacedObjectLiteralMap; 5283 // Load RewriteException back. 5284 method.load(rewriteExceptionType, lvarCount); 5285 // Get rid of the stored reference 5286 method.loadNull(); 5287 method.storeHidden(Type.OBJECT, lvarCount); 5288 // Mark it dead 5289 method.markDeadSlots(lvarCount, Type.OBJECT.getSlots()); 5290 5291 // Load return value on the stack 5292 method.invoke(RewriteException.GET_RETURN_VALUE); 5293 5294 final Type returnValueType = ci.getReturnValueType(); 5295 5296 // Set up an exception handler for primitive type conversion of return value if needed 5297 boolean needsCatch = false; 5298 final Label targetCatchLabel = ci.catchLabel; 5299 Label _try = null; 5300 if(returnValueType.isPrimitive()) { 5301 // If the conversion throws an exception, we want to report the line number of the continuation point. 5302 method.lineNumber(ci.lineNumber); 5303 5304 if(targetCatchLabel != METHOD_BOUNDARY) { 5305 _try = new Label(""); 5306 method.label(_try); 5307 needsCatch = true; 5308 } 5309 } 5310 5311 // Convert return value 5312 method.convert(returnValueType); 5313 5314 final int scopePopCount = needsCatch ? ci.exceptionScopePops : 0; 5315 5316 // Declare a try/catch for the conversion. If no scopes need to be popped until the target catch block, just 5317 // jump into it. Otherwise, we'll need to create a scope-popping catch block below. 5318 final Label catchLabel = scopePopCount > 0 ? new Label("") : targetCatchLabel; 5319 if(needsCatch) { 5320 final Label _end_try = new Label(""); 5321 method.label(_end_try); 5322 method._try(_try, _end_try, catchLabel); 5323 } 5324 5325 // Jump to continuation point 5326 method._goto(ci.getTargetLabel()); 5327 5328 // Make a scope-popping exception delegate if needed 5329 if(catchLabel != targetCatchLabel) { 5330 method.lineNumber(0); 5331 assert scopePopCount > 0; 5332 method._catch(catchLabel); 5333 popScopes(scopePopCount); 5334 method.uncheckedGoto(targetCatchLabel); 5335 } 5336 } 5337 }