CodeGenerator.java revision 971:c93b6091b11e
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 26package jdk.nashorn.internal.codegen; 27 28import static jdk.nashorn.internal.codegen.ClassEmitter.Flag.PRIVATE; 29import static jdk.nashorn.internal.codegen.ClassEmitter.Flag.STATIC; 30import static jdk.nashorn.internal.codegen.CompilerConstants.ARGUMENTS; 31import static jdk.nashorn.internal.codegen.CompilerConstants.CALLEE; 32import static jdk.nashorn.internal.codegen.CompilerConstants.CREATE_PROGRAM_FUNCTION; 33import static jdk.nashorn.internal.codegen.CompilerConstants.GET_MAP; 34import static jdk.nashorn.internal.codegen.CompilerConstants.GET_STRING; 35import static jdk.nashorn.internal.codegen.CompilerConstants.QUICK_PREFIX; 36import static jdk.nashorn.internal.codegen.CompilerConstants.REGEX_PREFIX; 37import static jdk.nashorn.internal.codegen.CompilerConstants.RETURN; 38import static jdk.nashorn.internal.codegen.CompilerConstants.SCOPE; 39import static jdk.nashorn.internal.codegen.CompilerConstants.SPLIT_ARRAY_ARG; 40import static jdk.nashorn.internal.codegen.CompilerConstants.SPLIT_PREFIX; 41import static jdk.nashorn.internal.codegen.CompilerConstants.THIS; 42import static jdk.nashorn.internal.codegen.CompilerConstants.VARARGS; 43import static jdk.nashorn.internal.codegen.CompilerConstants.constructorNoLookup; 44import static jdk.nashorn.internal.codegen.CompilerConstants.interfaceCallNoLookup; 45import static jdk.nashorn.internal.codegen.CompilerConstants.methodDescriptor; 46import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup; 47import static jdk.nashorn.internal.codegen.CompilerConstants.typeDescriptor; 48import static jdk.nashorn.internal.codegen.CompilerConstants.virtualCallNoLookup; 49import static jdk.nashorn.internal.codegen.ObjectClassGenerator.OBJECT_FIELDS_ONLY; 50import static jdk.nashorn.internal.ir.Symbol.HAS_SLOT; 51import static jdk.nashorn.internal.ir.Symbol.IS_INTERNAL; 52import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.INVALID_PROGRAM_POINT; 53import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.isValid; 54import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_APPLY_TO_CALL; 55import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_FAST_SCOPE; 56import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_OPTIMISTIC; 57import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_PROGRAM_POINT_SHIFT; 58import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_SCOPE; 59 60import java.io.PrintWriter; 61import java.util.ArrayDeque; 62import java.util.ArrayList; 63import java.util.Arrays; 64import java.util.BitSet; 65import java.util.Collection; 66import java.util.Collections; 67import java.util.Deque; 68import java.util.EnumSet; 69import java.util.HashMap; 70import java.util.HashSet; 71import java.util.Iterator; 72import java.util.LinkedList; 73import java.util.List; 74import java.util.Map; 75import java.util.Set; 76import java.util.TreeMap; 77import java.util.function.Supplier; 78import jdk.nashorn.internal.IntDeque; 79import jdk.nashorn.internal.codegen.ClassEmitter.Flag; 80import jdk.nashorn.internal.codegen.CompilerConstants.Call; 81import jdk.nashorn.internal.codegen.types.ArrayType; 82import jdk.nashorn.internal.codegen.types.Type; 83import jdk.nashorn.internal.ir.AccessNode; 84import jdk.nashorn.internal.ir.BaseNode; 85import jdk.nashorn.internal.ir.BinaryNode; 86import jdk.nashorn.internal.ir.Block; 87import jdk.nashorn.internal.ir.BlockStatement; 88import jdk.nashorn.internal.ir.BreakNode; 89import jdk.nashorn.internal.ir.BreakableNode; 90import jdk.nashorn.internal.ir.CallNode; 91import jdk.nashorn.internal.ir.CaseNode; 92import jdk.nashorn.internal.ir.CatchNode; 93import jdk.nashorn.internal.ir.ContinueNode; 94import jdk.nashorn.internal.ir.EmptyNode; 95import jdk.nashorn.internal.ir.Expression; 96import jdk.nashorn.internal.ir.ExpressionStatement; 97import jdk.nashorn.internal.ir.ForNode; 98import jdk.nashorn.internal.ir.FunctionNode; 99import jdk.nashorn.internal.ir.FunctionNode.CompilationState; 100import jdk.nashorn.internal.ir.IdentNode; 101import jdk.nashorn.internal.ir.IfNode; 102import jdk.nashorn.internal.ir.IndexNode; 103import jdk.nashorn.internal.ir.JoinPredecessor; 104import jdk.nashorn.internal.ir.JoinPredecessorExpression; 105import jdk.nashorn.internal.ir.LabelNode; 106import jdk.nashorn.internal.ir.LexicalContext; 107import jdk.nashorn.internal.ir.LexicalContextNode; 108import jdk.nashorn.internal.ir.LiteralNode; 109import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode; 110import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode.ArrayUnit; 111import jdk.nashorn.internal.ir.LiteralNode.PrimitiveLiteralNode; 112import jdk.nashorn.internal.ir.LocalVariableConversion; 113import jdk.nashorn.internal.ir.LoopNode; 114import jdk.nashorn.internal.ir.Node; 115import jdk.nashorn.internal.ir.ObjectNode; 116import jdk.nashorn.internal.ir.Optimistic; 117import jdk.nashorn.internal.ir.PropertyNode; 118import jdk.nashorn.internal.ir.ReturnNode; 119import jdk.nashorn.internal.ir.RuntimeNode; 120import jdk.nashorn.internal.ir.RuntimeNode.Request; 121import jdk.nashorn.internal.ir.SplitNode; 122import jdk.nashorn.internal.ir.Statement; 123import jdk.nashorn.internal.ir.SwitchNode; 124import jdk.nashorn.internal.ir.Symbol; 125import jdk.nashorn.internal.ir.TernaryNode; 126import jdk.nashorn.internal.ir.ThrowNode; 127import jdk.nashorn.internal.ir.TryNode; 128import jdk.nashorn.internal.ir.UnaryNode; 129import jdk.nashorn.internal.ir.VarNode; 130import jdk.nashorn.internal.ir.WhileNode; 131import jdk.nashorn.internal.ir.WithNode; 132import jdk.nashorn.internal.ir.visitor.NodeOperatorVisitor; 133import jdk.nashorn.internal.ir.visitor.NodeVisitor; 134import jdk.nashorn.internal.objects.Global; 135import jdk.nashorn.internal.objects.ScriptFunctionImpl; 136import jdk.nashorn.internal.parser.Lexer.RegexToken; 137import jdk.nashorn.internal.parser.TokenType; 138import jdk.nashorn.internal.runtime.Context; 139import jdk.nashorn.internal.runtime.Debug; 140import jdk.nashorn.internal.runtime.ECMAException; 141import jdk.nashorn.internal.runtime.JSType; 142import jdk.nashorn.internal.runtime.OptimisticReturnFilters; 143import jdk.nashorn.internal.runtime.PropertyMap; 144import jdk.nashorn.internal.runtime.RecompilableScriptFunctionData; 145import jdk.nashorn.internal.runtime.RewriteException; 146import jdk.nashorn.internal.runtime.Scope; 147import jdk.nashorn.internal.runtime.ScriptEnvironment; 148import jdk.nashorn.internal.runtime.ScriptFunction; 149import jdk.nashorn.internal.runtime.ScriptObject; 150import jdk.nashorn.internal.runtime.ScriptRuntime; 151import jdk.nashorn.internal.runtime.Source; 152import jdk.nashorn.internal.runtime.Undefined; 153import jdk.nashorn.internal.runtime.UnwarrantedOptimismException; 154import jdk.nashorn.internal.runtime.arrays.ArrayData; 155import jdk.nashorn.internal.runtime.linker.LinkerCallSite; 156import jdk.nashorn.internal.runtime.logging.DebugLogger; 157import jdk.nashorn.internal.runtime.logging.Loggable; 158import jdk.nashorn.internal.runtime.logging.Logger; 159import jdk.nashorn.internal.runtime.options.Options; 160 161/** 162 * This is the lowest tier of the code generator. It takes lowered ASTs emitted 163 * from Lower and emits Java byte code. The byte code emission logic is broken 164 * out into MethodEmitter. MethodEmitter works internally with a type stack, and 165 * keeps track of the contents of the byte code stack. This way we avoid a large 166 * number of special cases on the form 167 * <pre> 168 * if (type == INT) { 169 * visitInsn(ILOAD, slot); 170 * } else if (type == DOUBLE) { 171 * visitInsn(DOUBLE, slot); 172 * } 173 * </pre> 174 * This quickly became apparent when the code generator was generalized to work 175 * with all types, and not just numbers or objects. 176 * <p> 177 * The CodeGenerator visits nodes only once, tags them as resolved and emits 178 * bytecode for them. 179 */ 180@Logger(name="codegen") 181final class CodeGenerator extends NodeOperatorVisitor<CodeGeneratorLexicalContext> implements Loggable { 182 183 private static final Type SCOPE_TYPE = Type.typeFor(ScriptObject.class); 184 185 private static final String GLOBAL_OBJECT = Type.getInternalName(Global.class); 186 187 private static final String SCRIPTFUNCTION_IMPL_NAME = Type.getInternalName(ScriptFunctionImpl.class); 188 private static final Type SCRIPTFUNCTION_IMPL_TYPE = Type.typeFor(ScriptFunction.class); 189 190 private static final Call CREATE_REWRITE_EXCEPTION = CompilerConstants.staticCallNoLookup(RewriteException.class, 191 "create", RewriteException.class, UnwarrantedOptimismException.class, Object[].class, String[].class); 192 private static final Call CREATE_REWRITE_EXCEPTION_REST_OF = CompilerConstants.staticCallNoLookup(RewriteException.class, 193 "create", RewriteException.class, UnwarrantedOptimismException.class, Object[].class, String[].class, int[].class); 194 195 private static final Call ENSURE_INT = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class, 196 "ensureInt", int.class, Object.class, int.class); 197 private static final Call ENSURE_LONG = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class, 198 "ensureLong", long.class, Object.class, int.class); 199 private static final Call ENSURE_NUMBER = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class, 200 "ensureNumber", double.class, Object.class, int.class); 201 202 private static final Class<?> ITERATOR_CLASS = Iterator.class; 203 static { 204 assert ITERATOR_CLASS == CompilerConstants.ITERATOR_PREFIX.type(); 205 } 206 private static final Type ITERATOR_TYPE = Type.typeFor(ITERATOR_CLASS); 207 private static final Type EXCEPTION_TYPE = Type.typeFor(CompilerConstants.EXCEPTION_PREFIX.type()); 208 209 /** Constant data & installation. The only reason the compiler keeps this is because it is assigned 210 * by reflection in class installation */ 211 private final Compiler compiler; 212 213 /** Is the current code submitted by 'eval' call? */ 214 private final boolean evalCode; 215 216 /** Call site flags given to the code generator to be used for all generated call sites */ 217 private final int callSiteFlags; 218 219 /** How many regexp fields have been emitted */ 220 private int regexFieldCount; 221 222 /** Line number for last statement. If we encounter a new line number, line number bytecode information 223 * needs to be generated */ 224 private int lastLineNumber = -1; 225 226 /** When should we stop caching regexp expressions in fields to limit bytecode size? */ 227 private static final int MAX_REGEX_FIELDS = 2 * 1024; 228 229 /** Current method emitter */ 230 private MethodEmitter method; 231 232 /** Current compile unit */ 233 private CompileUnit unit; 234 235 private final DebugLogger log; 236 237 /** From what size should we use spill instead of fields for JavaScript objects? */ 238 private static final int OBJECT_SPILL_THRESHOLD = Options.getIntProperty("nashorn.spill.threshold", 256); 239 240 private static boolean assertsEnabled = false; 241 static { 242 assert assertsEnabled = true; // Intentional side effect 243 } 244 245 private final Set<String> emittedMethods = new HashSet<>(); 246 247 // Function Id -> ContinuationInfo. Used by compilation of rest-of function only. 248 private final Map<Integer, ContinuationInfo> fnIdToContinuationInfo = new HashMap<>(); 249 250 private final Deque<Label> scopeEntryLabels = new ArrayDeque<>(); 251 252 private static final Label METHOD_BOUNDARY = new Label(""); 253 private final Deque<Label> catchLabels = new ArrayDeque<>(); 254 // Number of live locals on entry to (and thus also break from) labeled blocks. 255 private final IntDeque labeledBlockBreakLiveLocals = new IntDeque(); 256 257 //is this a rest of compilation 258 private final int[] continuationEntryPoints; 259 260 /** 261 * Constructor. 262 * 263 * @param compiler 264 */ 265 CodeGenerator(final Compiler compiler, final int[] continuationEntryPoints) { 266 super(new CodeGeneratorLexicalContext()); 267 this.compiler = compiler; 268 this.evalCode = compiler.getSource().isEvalCode(); 269 this.continuationEntryPoints = continuationEntryPoints; 270 this.callSiteFlags = compiler.getScriptEnvironment()._callsite_flags; 271 this.log = initLogger(compiler.getContext()); 272 } 273 274 @Override 275 public DebugLogger getLogger() { 276 return log; 277 } 278 279 @Override 280 public DebugLogger initLogger(final Context context) { 281 return context.getLogger(this.getClass()); 282 } 283 284 /** 285 * Gets the call site flags, adding the strict flag if the current function 286 * being generated is in strict mode 287 * 288 * @return the correct flags for a call site in the current function 289 */ 290 int getCallSiteFlags() { 291 return lc.getCurrentFunction().getCallSiteFlags() | callSiteFlags; 292 } 293 294 /** 295 * Are we generating code for 'eval' code? 296 * @return true if currently compiled code is 'eval' code. 297 */ 298 boolean isEvalCode() { 299 return evalCode; 300 } 301 302 /** 303 * Load an identity node 304 * 305 * @param identNode an identity node to load 306 * @return the method generator used 307 */ 308 private MethodEmitter loadIdent(final IdentNode identNode, final TypeBounds resultBounds) { 309 final Symbol symbol = identNode.getSymbol(); 310 311 if (!symbol.isScope()) { 312 final Type type = identNode.getType(); 313 if(type == Type.UNDEFINED) { 314 return method.loadUndefined(resultBounds.widest); 315 } 316 317 assert symbol.hasSlot() || symbol.isParam(); 318 return method.load(identNode); 319 } 320 321 assert identNode.getSymbol().isScope() : identNode + " is not in scope!"; 322 final int flags = CALLSITE_SCOPE | getCallSiteFlags(); 323 if (isFastScope(symbol)) { 324 // Only generate shared scope getter for fast-scope symbols so we know we can dial in correct scope. 325 if (symbol.getUseCount() > SharedScopeCall.FAST_SCOPE_GET_THRESHOLD && !isOptimisticOrRestOf()) { 326 method.loadCompilerConstant(SCOPE); 327 // As shared scope vars are only used in non-optimistic compilation, we switch from using TypeBounds to 328 // just a single definitive type, resultBounds.widest. 329 loadSharedScopeVar(resultBounds.widest, symbol, flags); 330 } else { 331 new LoadFastScopeVar(identNode, resultBounds, flags).emit(); 332 } 333 } else { 334 //slow scope load, we have no proto depth 335 new LoadScopeVar(identNode, resultBounds, flags).emit(); 336 } 337 338 return method; 339 } 340 341 private boolean isRestOf() { 342 return continuationEntryPoints != null; 343 } 344 345 private boolean isOptimisticOrRestOf() { 346 return useOptimisticTypes() || isRestOf(); 347 } 348 349 private boolean isCurrentContinuationEntryPoint(final int programPoint) { 350 return isRestOf() && getCurrentContinuationEntryPoint() == programPoint; 351 } 352 353 private int[] getContinuationEntryPoints() { 354 return isRestOf() ? continuationEntryPoints : null; 355 } 356 357 private int getCurrentContinuationEntryPoint() { 358 return isRestOf() ? continuationEntryPoints[0] : INVALID_PROGRAM_POINT; 359 } 360 361 private boolean isContinuationEntryPoint(final int programPoint) { 362 if (isRestOf()) { 363 assert continuationEntryPoints != null; 364 for (final int cep : continuationEntryPoints) { 365 if (cep == programPoint) { 366 return true; 367 } 368 } 369 } 370 return false; 371 } 372 373 /** 374 * Check if this symbol can be accessed directly with a putfield or getfield or dynamic load 375 * 376 * @param symbol symbol to check for fast scope 377 * @return true if fast scope 378 */ 379 private boolean isFastScope(final Symbol symbol) { 380 if (!symbol.isScope()) { 381 return false; 382 } 383 384 if (!lc.inDynamicScope()) { 385 // If there's no with or eval in context, and the symbol is marked as scoped, it is fast scoped. Such a 386 // symbol must either be global, or its defining block must need scope. 387 assert symbol.isGlobal() || lc.getDefiningBlock(symbol).needsScope() : symbol.getName(); 388 return true; 389 } 390 391 if (symbol.isGlobal()) { 392 // Shortcut: if there's a with or eval in context, globals can't be fast scoped 393 return false; 394 } 395 396 // Otherwise, check if there's a dynamic scope between use of the symbol and its definition 397 final String name = symbol.getName(); 398 boolean previousWasBlock = false; 399 for (final Iterator<LexicalContextNode> it = lc.getAllNodes(); it.hasNext();) { 400 final LexicalContextNode node = it.next(); 401 if (node instanceof Block) { 402 // If this block defines the symbol, then we can fast scope the symbol. 403 final Block block = (Block)node; 404 if (block.getExistingSymbol(name) == symbol) { 405 assert block.needsScope(); 406 return true; 407 } 408 previousWasBlock = true; 409 } else { 410 if (node instanceof WithNode && previousWasBlock || node instanceof FunctionNode && ((FunctionNode)node).needsDynamicScope()) { 411 // If we hit a scope that can have symbols introduced into it at run time before finding the defining 412 // block, the symbol can't be fast scoped. A WithNode only counts if we've immediately seen a block 413 // before - its block. Otherwise, we are currently processing the WithNode's expression, and that's 414 // obviously not subjected to introducing new symbols. 415 return false; 416 } 417 previousWasBlock = false; 418 } 419 } 420 // Should've found the symbol defined in a block 421 throw new AssertionError(); 422 } 423 424 private MethodEmitter loadSharedScopeVar(final Type valueType, final Symbol symbol, final int flags) { 425 assert !isOptimisticOrRestOf(); 426 if (isFastScope(symbol)) { 427 method.load(getScopeProtoDepth(lc.getCurrentBlock(), symbol)); 428 } else { 429 method.load(-1); 430 } 431 return lc.getScopeGet(unit, symbol, valueType, flags | CALLSITE_FAST_SCOPE).generateInvoke(method); 432 } 433 434 private class LoadScopeVar extends OptimisticOperation { 435 final IdentNode identNode; 436 private final int flags; 437 438 LoadScopeVar(final IdentNode identNode, final TypeBounds resultBounds, final int flags) { 439 super(identNode, resultBounds); 440 this.identNode = identNode; 441 this.flags = flags; 442 } 443 444 @Override 445 void loadStack() { 446 method.loadCompilerConstant(SCOPE); 447 getProto(); 448 } 449 450 void getProto() { 451 //empty 452 } 453 454 @Override 455 void consumeStack() { 456 // If this is either __FILE__, __DIR__, or __LINE__ then load the property initially as Object as we'd convert 457 // it anyway for replaceLocationPropertyPlaceholder. 458 if(identNode.isCompileTimePropertyName()) { 459 method.dynamicGet(Type.OBJECT, identNode.getSymbol().getName(), flags, identNode.isFunction()); 460 replaceCompileTimeProperty(); 461 } else { 462 dynamicGet(identNode.getSymbol().getName(), flags, identNode.isFunction()); 463 } 464 } 465 } 466 467 private class LoadFastScopeVar extends LoadScopeVar { 468 LoadFastScopeVar(final IdentNode identNode, final TypeBounds resultBounds, final int flags) { 469 super(identNode, resultBounds, flags | CALLSITE_FAST_SCOPE); 470 } 471 472 @Override 473 void getProto() { 474 loadFastScopeProto(identNode.getSymbol(), false); 475 } 476 } 477 478 private MethodEmitter storeFastScopeVar(final Symbol symbol, final int flags) { 479 loadFastScopeProto(symbol, true); 480 method.dynamicSet(symbol.getName(), flags | CALLSITE_FAST_SCOPE); 481 return method; 482 } 483 484 private int getScopeProtoDepth(final Block startingBlock, final Symbol symbol) { 485 //walk up the chain from starting block and when we bump into the current function boundary, add the external 486 //information. 487 final FunctionNode fn = lc.getCurrentFunction(); 488 final int fnId = fn.getId(); 489 final int externalDepth = compiler.getScriptFunctionData(fnId).getExternalSymbolDepth(symbol.getName()); 490 491 //count the number of scopes from this place to the start of the function 492 493 final int internalDepth = FindScopeDepths.findInternalDepth(lc, fn, startingBlock, symbol); 494 final int scopesToStart = FindScopeDepths.findScopesToStart(lc, fn, startingBlock); 495 int depth = 0; 496 if (internalDepth == -1) { 497 depth = scopesToStart + externalDepth; 498 } else { 499 assert internalDepth <= scopesToStart; 500 depth = internalDepth; 501 } 502 503 return depth; 504 } 505 506 private void loadFastScopeProto(final Symbol symbol, final boolean swap) { 507 final int depth = getScopeProtoDepth(lc.getCurrentBlock(), symbol); 508 assert depth != -1 : "Couldn't find scope depth for symbol " + symbol.getName() + " in " + lc.getCurrentFunction(); 509 if (depth > 0) { 510 if (swap) { 511 method.swap(); 512 } 513 for (int i = 0; i < depth; i++) { 514 method.invoke(ScriptObject.GET_PROTO); 515 } 516 if (swap) { 517 method.swap(); 518 } 519 } 520 } 521 522 /** 523 * Generate code that loads this node to the stack, not constraining its type 524 * 525 * @param expr node to load 526 * 527 * @return the method emitter used 528 */ 529 private MethodEmitter loadExpressionUnbounded(final Expression expr) { 530 return loadExpression(expr, TypeBounds.UNBOUNDED); 531 } 532 533 private MethodEmitter loadExpressionAsObject(final Expression expr) { 534 return loadExpression(expr, TypeBounds.OBJECT); 535 } 536 537 MethodEmitter loadExpressionAsBoolean(final Expression expr) { 538 return loadExpression(expr, TypeBounds.BOOLEAN); 539 } 540 541 // Test whether conversion from source to target involves a call of ES 9.1 ToPrimitive 542 // with possible side effects from calling an object's toString or valueOf methods. 543 private static boolean noToPrimitiveConversion(final Type source, final Type target) { 544 // Object to boolean conversion does not cause ToPrimitive call 545 return source.isJSPrimitive() || !target.isJSPrimitive() || target.isBoolean(); 546 } 547 548 MethodEmitter loadBinaryOperands(final BinaryNode binaryNode) { 549 return loadBinaryOperands(binaryNode.lhs(), binaryNode.rhs(), TypeBounds.UNBOUNDED.notWiderThan(binaryNode.getWidestOperandType()), false); 550 } 551 552 private MethodEmitter loadBinaryOperands(final Expression lhs, final Expression rhs, final TypeBounds explicitOperandBounds, final boolean baseAlreadyOnStack) { 553 // ECMAScript 5.1 specification (sections 11.5-11.11 and 11.13) prescribes that when evaluating a binary 554 // expression "LEFT op RIGHT", the order of operations must be: LOAD LEFT, LOAD RIGHT, CONVERT LEFT, CONVERT 555 // RIGHT, EXECUTE OP. Unfortunately, doing it in this order defeats potential optimizations that arise when we 556 // can combine a LOAD with a CONVERT operation (e.g. use a dynamic getter with the conversion target type as its 557 // return value). What we do here is reorder LOAD RIGHT and CONVERT LEFT when possible; it is possible only when 558 // we can prove that executing CONVERT LEFT can't have a side effect that changes the value of LOAD RIGHT. 559 // Basically, if we know that either LEFT already is a primitive value, or does not have to be converted to 560 // a primitive value, or RIGHT is an expression that loads without side effects, then we can do the 561 // reordering and collapse LOAD/CONVERT into a single operation; otherwise we need to do the more costly 562 // separate operations to preserve specification semantics. 563 564 // Operands' load type should not be narrower than the narrowest of the individual operand types, nor narrower 565 // than the lower explicit bound, but it should also not be wider than 566 final Type narrowestOperandType = Type.narrowest(Type.widest(lhs.getType(), rhs.getType()), explicitOperandBounds.widest); 567 final TypeBounds operandBounds = explicitOperandBounds.notNarrowerThan(narrowestOperandType); 568 if (noToPrimitiveConversion(lhs.getType(), explicitOperandBounds.widest) || rhs.isLocal()) { 569 // Can reorder. Combine load and convert into single operations. 570 loadExpression(lhs, operandBounds, baseAlreadyOnStack); 571 loadExpression(rhs, operandBounds, false); 572 } else { 573 // Can't reorder. Load and convert separately. 574 final TypeBounds safeConvertBounds = TypeBounds.UNBOUNDED.notNarrowerThan(narrowestOperandType); 575 loadExpression(lhs, safeConvertBounds, baseAlreadyOnStack); 576 loadExpression(rhs, safeConvertBounds, false); 577 method.swap().convert(operandBounds.within(method.peekType())).swap().convert(operandBounds.within(method.peekType())); 578 } 579 assert Type.generic(method.peekType()) == operandBounds.narrowest; 580 assert Type.generic(method.peekType(1)) == operandBounds.narrowest; 581 582 return method; 583 } 584 585 private static final class TypeBounds { 586 final Type narrowest; 587 final Type widest; 588 589 static final TypeBounds UNBOUNDED = new TypeBounds(Type.UNKNOWN, Type.OBJECT); 590 static final TypeBounds INT = exact(Type.INT); 591 static final TypeBounds NUMBER = exact(Type.NUMBER); 592 static final TypeBounds OBJECT = exact(Type.OBJECT); 593 static final TypeBounds BOOLEAN = exact(Type.BOOLEAN); 594 595 static TypeBounds exact(final Type type) { 596 return new TypeBounds(type, type); 597 } 598 599 TypeBounds(final Type narrowest, final Type widest) { 600 assert widest != null && widest != Type.UNDEFINED && widest != Type.UNKNOWN : widest; 601 assert narrowest != null && narrowest != Type.UNDEFINED : narrowest; 602 assert !narrowest.widerThan(widest) : narrowest + " wider than " + widest; 603 assert !widest.narrowerThan(narrowest); 604 this.narrowest = Type.generic(narrowest); 605 this.widest = Type.generic(widest); 606 } 607 608 TypeBounds notNarrowerThan(final Type type) { 609 return maybeNew(Type.narrowest(Type.widest(narrowest, type), widest), widest); 610 } 611 612 TypeBounds notWiderThan(final Type type) { 613 return maybeNew(Type.narrowest(narrowest, type), Type.narrowest(widest, type)); 614 } 615 616 boolean canBeNarrowerThan(final Type type) { 617 return narrowest.narrowerThan(type); 618 } 619 620 TypeBounds maybeNew(final Type newNarrowest, final Type newWidest) { 621 if(newNarrowest == narrowest && newWidest == widest) { 622 return this; 623 } 624 return new TypeBounds(newNarrowest, newWidest); 625 } 626 627 TypeBounds booleanToInt() { 628 return maybeNew(booleanToInt(narrowest), booleanToInt(widest)); 629 } 630 631 TypeBounds objectToNumber() { 632 return maybeNew(objectToNumber(narrowest), objectToNumber(widest)); 633 } 634 635 private static Type booleanToInt(final Type t) { 636 return t == Type.BOOLEAN ? Type.INT : t; 637 } 638 639 private static Type objectToNumber(final Type t) { 640 return t.isObject() ? Type.NUMBER : t; 641 } 642 643 Type within(final Type type) { 644 if(type.narrowerThan(narrowest)) { 645 return narrowest; 646 } 647 if(type.widerThan(widest)) { 648 return widest; 649 } 650 return type; 651 } 652 653 @Override 654 public String toString() { 655 return "[" + narrowest + ", " + widest + "]"; 656 } 657 } 658 659 MethodEmitter loadExpressionAsType(final Expression expr, final Type type) { 660 if(type == Type.BOOLEAN) { 661 return loadExpressionAsBoolean(expr); 662 } else if(type == Type.UNDEFINED) { 663 assert expr.getType() == Type.UNDEFINED; 664 return loadExpressionAsObject(expr); 665 } 666 // having no upper bound preserves semantics of optimistic operations in the expression (by not having them 667 // converted early) and then applies explicit conversion afterwards. 668 return loadExpression(expr, TypeBounds.UNBOUNDED.notNarrowerThan(type)).convert(type); 669 } 670 671 private MethodEmitter loadExpression(final Expression expr, final TypeBounds resultBounds) { 672 return loadExpression(expr, resultBounds, false); 673 } 674 675 /** 676 * Emits code for evaluating an expression and leaving its value on top of the stack, narrowing or widening it if 677 * necessary. 678 * @param expr the expression to load 679 * @param resultBounds the incoming type bounds. The value on the top of the stack is guaranteed to not be of narrower 680 * type than the narrowest bound, or wider type than the widest bound after it is loaded. 681 * @param baseAlreadyOnStack true if the base of an access or index node is already on the stack. Used to avoid 682 * double evaluation of bases in self-assignment expressions to access and index nodes. {@code Type.OBJECT} is used 683 * to indicate the widest possible type. 684 * @return the method emitter 685 */ 686 private MethodEmitter loadExpression(final Expression expr, final TypeBounds resultBounds, final boolean baseAlreadyOnStack) { 687 688 /* 689 * The load may be of type IdentNode, e.g. "x", AccessNode, e.g. "x.y" 690 * or IndexNode e.g. "x[y]". Both AccessNodes and IndexNodes are 691 * BaseNodes and the logic for loading the base object is reused 692 */ 693 final CodeGenerator codegen = this; 694 695 final Node currentDiscard = codegen.lc.getCurrentDiscard(); 696 expr.accept(new NodeOperatorVisitor<LexicalContext>(new LexicalContext()) { 697 @Override 698 public boolean enterIdentNode(final IdentNode identNode) { 699 loadIdent(identNode, resultBounds); 700 return false; 701 } 702 703 @Override 704 public boolean enterAccessNode(final AccessNode accessNode) { 705 new OptimisticOperation(accessNode, resultBounds) { 706 @Override 707 void loadStack() { 708 if (!baseAlreadyOnStack) { 709 loadExpressionAsObject(accessNode.getBase()); 710 } 711 assert method.peekType().isObject(); 712 } 713 @Override 714 void consumeStack() { 715 final int flags = getCallSiteFlags(); 716 dynamicGet(accessNode.getProperty(), flags, accessNode.isFunction()); 717 } 718 }.emit(baseAlreadyOnStack ? 1 : 0); 719 return false; 720 } 721 722 @Override 723 public boolean enterIndexNode(final IndexNode indexNode) { 724 new OptimisticOperation(indexNode, resultBounds) { 725 @Override 726 void loadStack() { 727 if (!baseAlreadyOnStack) { 728 loadExpressionAsObject(indexNode.getBase()); 729 loadExpressionUnbounded(indexNode.getIndex()); 730 } 731 } 732 @Override 733 void consumeStack() { 734 final int flags = getCallSiteFlags(); 735 dynamicGetIndex(flags, indexNode.isFunction()); 736 } 737 }.emit(baseAlreadyOnStack ? 2 : 0); 738 return false; 739 } 740 741 @Override 742 public boolean enterFunctionNode(final FunctionNode functionNode) { 743 // function nodes will always leave a constructed function object on stack, no need to load the symbol 744 // separately as in enterDefault() 745 lc.pop(functionNode); 746 functionNode.accept(codegen); 747 // NOTE: functionNode.accept() will produce a different FunctionNode that we discard. This incidentally 748 // doesn't cause problems as we're never touching FunctionNode again after it's visited here - codegen 749 // is the last element in the compilation pipeline, the AST it produces is not used externally. So, we 750 // re-push the original functionNode. 751 lc.push(functionNode); 752 return false; 753 } 754 755 @Override 756 public boolean enterASSIGN(final BinaryNode binaryNode) { 757 loadASSIGN(binaryNode); 758 return false; 759 } 760 761 @Override 762 public boolean enterASSIGN_ADD(final BinaryNode binaryNode) { 763 loadASSIGN_ADD(binaryNode); 764 return false; 765 } 766 767 @Override 768 public boolean enterASSIGN_BIT_AND(final BinaryNode binaryNode) { 769 loadASSIGN_BIT_AND(binaryNode); 770 return false; 771 } 772 773 @Override 774 public boolean enterASSIGN_BIT_OR(final BinaryNode binaryNode) { 775 loadASSIGN_BIT_OR(binaryNode); 776 return false; 777 } 778 779 @Override 780 public boolean enterASSIGN_BIT_XOR(final BinaryNode binaryNode) { 781 loadASSIGN_BIT_XOR(binaryNode); 782 return false; 783 } 784 785 @Override 786 public boolean enterASSIGN_DIV(final BinaryNode binaryNode) { 787 loadASSIGN_DIV(binaryNode); 788 return false; 789 } 790 791 @Override 792 public boolean enterASSIGN_MOD(final BinaryNode binaryNode) { 793 loadASSIGN_MOD(binaryNode); 794 return false; 795 } 796 797 @Override 798 public boolean enterASSIGN_MUL(final BinaryNode binaryNode) { 799 loadASSIGN_MUL(binaryNode); 800 return false; 801 } 802 803 @Override 804 public boolean enterASSIGN_SAR(final BinaryNode binaryNode) { 805 loadASSIGN_SAR(binaryNode); 806 return false; 807 } 808 809 @Override 810 public boolean enterASSIGN_SHL(final BinaryNode binaryNode) { 811 loadASSIGN_SHL(binaryNode); 812 return false; 813 } 814 815 @Override 816 public boolean enterASSIGN_SHR(final BinaryNode binaryNode) { 817 loadASSIGN_SHR(binaryNode); 818 return false; 819 } 820 821 @Override 822 public boolean enterASSIGN_SUB(final BinaryNode binaryNode) { 823 loadASSIGN_SUB(binaryNode); 824 return false; 825 } 826 827 @Override 828 public boolean enterCallNode(final CallNode callNode) { 829 return loadCallNode(callNode, resultBounds); 830 } 831 832 @Override 833 public boolean enterLiteralNode(final LiteralNode<?> literalNode) { 834 loadLiteral(literalNode, resultBounds); 835 return false; 836 } 837 838 @Override 839 public boolean enterTernaryNode(final TernaryNode ternaryNode) { 840 loadTernaryNode(ternaryNode, resultBounds); 841 return false; 842 } 843 844 @Override 845 public boolean enterADD(final BinaryNode binaryNode) { 846 loadADD(binaryNode, resultBounds); 847 return false; 848 } 849 850 @Override 851 public boolean enterSUB(final UnaryNode unaryNode) { 852 loadSUB(unaryNode, resultBounds); 853 return false; 854 } 855 856 @Override 857 public boolean enterSUB(final BinaryNode binaryNode) { 858 loadSUB(binaryNode, resultBounds); 859 return false; 860 } 861 862 @Override 863 public boolean enterMUL(final BinaryNode binaryNode) { 864 loadMUL(binaryNode, resultBounds); 865 return false; 866 } 867 868 @Override 869 public boolean enterDIV(final BinaryNode binaryNode) { 870 loadDIV(binaryNode, resultBounds); 871 return false; 872 } 873 874 @Override 875 public boolean enterMOD(final BinaryNode binaryNode) { 876 loadMOD(binaryNode, resultBounds); 877 return false; 878 } 879 880 @Override 881 public boolean enterSAR(final BinaryNode binaryNode) { 882 loadSAR(binaryNode); 883 return false; 884 } 885 886 @Override 887 public boolean enterSHL(final BinaryNode binaryNode) { 888 loadSHL(binaryNode); 889 return false; 890 } 891 892 @Override 893 public boolean enterSHR(final BinaryNode binaryNode) { 894 loadSHR(binaryNode); 895 return false; 896 } 897 898 @Override 899 public boolean enterCOMMALEFT(final BinaryNode binaryNode) { 900 loadCOMMALEFT(binaryNode, resultBounds); 901 return false; 902 } 903 904 @Override 905 public boolean enterCOMMARIGHT(final BinaryNode binaryNode) { 906 loadCOMMARIGHT(binaryNode, resultBounds); 907 return false; 908 } 909 910 @Override 911 public boolean enterAND(final BinaryNode binaryNode) { 912 loadAND_OR(binaryNode, resultBounds, true); 913 return false; 914 } 915 916 @Override 917 public boolean enterOR(final BinaryNode binaryNode) { 918 loadAND_OR(binaryNode, resultBounds, false); 919 return false; 920 } 921 922 @Override 923 public boolean enterNOT(final UnaryNode unaryNode) { 924 loadNOT(unaryNode); 925 return false; 926 } 927 928 @Override 929 public boolean enterADD(final UnaryNode unaryNode) { 930 loadADD(unaryNode, resultBounds); 931 return false; 932 } 933 934 @Override 935 public boolean enterBIT_NOT(final UnaryNode unaryNode) { 936 loadBIT_NOT(unaryNode); 937 return false; 938 } 939 940 @Override 941 public boolean enterBIT_AND(final BinaryNode binaryNode) { 942 loadBIT_AND(binaryNode); 943 return false; 944 } 945 946 @Override 947 public boolean enterBIT_OR(final BinaryNode binaryNode) { 948 loadBIT_OR(binaryNode); 949 return false; 950 } 951 952 @Override 953 public boolean enterBIT_XOR(final BinaryNode binaryNode) { 954 loadBIT_XOR(binaryNode); 955 return false; 956 } 957 958 @Override 959 public boolean enterVOID(final UnaryNode unaryNode) { 960 loadVOID(unaryNode, resultBounds); 961 return false; 962 } 963 964 @Override 965 public boolean enterEQ(final BinaryNode binaryNode) { 966 loadCmp(binaryNode, Condition.EQ); 967 return false; 968 } 969 970 @Override 971 public boolean enterEQ_STRICT(final BinaryNode binaryNode) { 972 loadCmp(binaryNode, Condition.EQ); 973 return false; 974 } 975 976 @Override 977 public boolean enterGE(final BinaryNode binaryNode) { 978 loadCmp(binaryNode, Condition.GE); 979 return false; 980 } 981 982 @Override 983 public boolean enterGT(final BinaryNode binaryNode) { 984 loadCmp(binaryNode, Condition.GT); 985 return false; 986 } 987 988 @Override 989 public boolean enterLE(final BinaryNode binaryNode) { 990 loadCmp(binaryNode, Condition.LE); 991 return false; 992 } 993 994 @Override 995 public boolean enterLT(final BinaryNode binaryNode) { 996 loadCmp(binaryNode, Condition.LT); 997 return false; 998 } 999 1000 @Override 1001 public boolean enterNE(final BinaryNode binaryNode) { 1002 loadCmp(binaryNode, Condition.NE); 1003 return false; 1004 } 1005 1006 @Override 1007 public boolean enterNE_STRICT(final BinaryNode binaryNode) { 1008 loadCmp(binaryNode, Condition.NE); 1009 return false; 1010 } 1011 1012 @Override 1013 public boolean enterObjectNode(final ObjectNode objectNode) { 1014 loadObjectNode(objectNode); 1015 return false; 1016 } 1017 1018 @Override 1019 public boolean enterRuntimeNode(final RuntimeNode runtimeNode) { 1020 loadRuntimeNode(runtimeNode); 1021 return false; 1022 } 1023 1024 @Override 1025 public boolean enterNEW(final UnaryNode unaryNode) { 1026 loadNEW(unaryNode); 1027 return false; 1028 } 1029 1030 @Override 1031 public boolean enterDECINC(final UnaryNode unaryNode) { 1032 loadDECINC(unaryNode); 1033 return false; 1034 } 1035 1036 @Override 1037 public boolean enterJoinPredecessorExpression(final JoinPredecessorExpression joinExpr) { 1038 loadExpression(joinExpr.getExpression(), resultBounds); 1039 return false; 1040 } 1041 1042 @Override 1043 public boolean enterDefault(final Node otherNode) { 1044 // Must have handled all expressions that can legally be encountered. 1045 throw new AssertionError(otherNode.getClass().getName()); 1046 } 1047 }); 1048 if(currentDiscard != expr) { 1049 coerceStackTop(resultBounds); 1050 } 1051 return method; 1052 } 1053 1054 private MethodEmitter coerceStackTop(final TypeBounds typeBounds) { 1055 return method.convert(typeBounds.within(method.peekType())); 1056 } 1057 1058 /** 1059 * Closes any still open entries for this block's local variables in the bytecode local variable table. 1060 * 1061 * @param block block containing symbols. 1062 */ 1063 private void closeBlockVariables(final Block block) { 1064 for (final Symbol symbol : block.getSymbols()) { 1065 if (symbol.isBytecodeLocal()) { 1066 method.closeLocalVariable(symbol, block.getBreakLabel()); 1067 } 1068 } 1069 } 1070 1071 @Override 1072 public boolean enterBlock(final Block block) { 1073 method.label(block.getEntryLabel()); 1074 if(!method.isReachable()) { 1075 return false; 1076 } 1077 if(lc.isFunctionBody() && emittedMethods.contains(lc.getCurrentFunction().getName())) { 1078 return false; 1079 } 1080 initLocals(block); 1081 1082 assert lc.getUsedSlotCount() == method.getFirstTemp(); 1083 return true; 1084 } 1085 1086 private boolean useOptimisticTypes() { 1087 return !lc.inSplitNode() && compiler.useOptimisticTypes(); 1088 } 1089 1090 @Override 1091 public Node leaveBlock(final Block block) { 1092 popBlockScope(block); 1093 method.beforeJoinPoint(block); 1094 1095 closeBlockVariables(block); 1096 lc.releaseSlots(); 1097 assert !method.isReachable() || (lc.isFunctionBody() ? 0 : lc.getUsedSlotCount()) == method.getFirstTemp() : 1098 "reachable="+method.isReachable() + 1099 " isFunctionBody=" + lc.isFunctionBody() + 1100 " usedSlotCount=" + lc.getUsedSlotCount() + 1101 " firstTemp=" + method.getFirstTemp(); 1102 1103 return block; 1104 } 1105 1106 private void popBlockScope(final Block block) { 1107 final Label breakLabel = block.getBreakLabel(); 1108 1109 if(!block.needsScope() || lc.isFunctionBody()) { 1110 emitBlockBreakLabel(breakLabel); 1111 return; 1112 } 1113 1114 final Label beginTryLabel = scopeEntryLabels.pop(); 1115 final Label recoveryLabel = new Label("block_popscope_catch"); 1116 emitBlockBreakLabel(breakLabel); 1117 final boolean bodyCanThrow = breakLabel.isAfter(beginTryLabel); 1118 if(bodyCanThrow) { 1119 method._try(beginTryLabel, breakLabel, recoveryLabel); 1120 } 1121 1122 Label afterCatchLabel = null; 1123 1124 if(method.isReachable()) { 1125 popScope(); 1126 if(bodyCanThrow) { 1127 afterCatchLabel = new Label("block_after_catch"); 1128 method._goto(afterCatchLabel); 1129 } 1130 } 1131 1132 if(bodyCanThrow) { 1133 assert !method.isReachable(); 1134 method._catch(recoveryLabel); 1135 popScopeException(); 1136 method.athrow(); 1137 } 1138 if(afterCatchLabel != null) { 1139 method.label(afterCatchLabel); 1140 } 1141 } 1142 1143 private void emitBlockBreakLabel(final Label breakLabel) { 1144 // TODO: this is totally backwards. Block should not be breakable, LabelNode should be breakable. 1145 final LabelNode labelNode = lc.getCurrentBlockLabelNode(); 1146 if(labelNode != null) { 1147 // Only have conversions if we're reachable 1148 assert labelNode.getLocalVariableConversion() == null || method.isReachable(); 1149 method.beforeJoinPoint(labelNode); 1150 method.breakLabel(breakLabel, labeledBlockBreakLiveLocals.pop()); 1151 } else { 1152 method.label(breakLabel); 1153 } 1154 } 1155 1156 private void popScope() { 1157 popScopes(1); 1158 } 1159 1160 /** 1161 * Pop scope as part of an exception handler. Similar to {@code popScope()} but also takes care of adjusting the 1162 * number of scopes that needs to be popped in case a rest-of continuation handler encounters an exception while 1163 * performing a ToPrimitive conversion. 1164 */ 1165 private void popScopeException() { 1166 popScope(); 1167 final ContinuationInfo ci = getContinuationInfo(); 1168 if(ci != null) { 1169 final Label catchLabel = ci.catchLabel; 1170 if(catchLabel != METHOD_BOUNDARY && catchLabel == catchLabels.peek()) { 1171 ++ci.exceptionScopePops; 1172 } 1173 } 1174 } 1175 1176 private void popScopesUntil(final LexicalContextNode until) { 1177 popScopes(lc.getScopeNestingLevelTo(until)); 1178 } 1179 1180 private void popScopes(final int count) { 1181 if(count == 0) { 1182 return; 1183 } 1184 assert count > 0; // together with count == 0 check, asserts nonnegative count 1185 if (!method.hasScope()) { 1186 // We can sometimes invoke this method even if the method has no slot for the scope object. Typical example: 1187 // for(;;) { with({}) { break; } }. WithNode normally creates a scope, but if it uses no identifiers and 1188 // nothing else forces creation of a scope in the method, we just won't have the :scope local variable. 1189 return; 1190 } 1191 method.loadCompilerConstant(SCOPE); 1192 for(int i = 0; i < count; ++i) { 1193 method.invoke(ScriptObject.GET_PROTO); 1194 } 1195 method.storeCompilerConstant(SCOPE); 1196 } 1197 1198 @Override 1199 public boolean enterBreakNode(final BreakNode breakNode) { 1200 if(!method.isReachable()) { 1201 return false; 1202 } 1203 enterStatement(breakNode); 1204 1205 method.beforeJoinPoint(breakNode); 1206 final BreakableNode breakFrom = lc.getBreakable(breakNode.getLabelName()); 1207 popScopesUntil(breakFrom); 1208 final Label breakLabel = breakFrom.getBreakLabel(); 1209 breakLabel.markAsBreakTarget(); 1210 method.splitAwareGoto(lc, breakLabel, breakFrom); 1211 1212 return false; 1213 } 1214 1215 private int loadArgs(final List<Expression> args) { 1216 final int argCount = args.size(); 1217 // arg have already been converted to objects here. 1218 if (argCount > LinkerCallSite.ARGLIMIT) { 1219 loadArgsArray(args); 1220 return 1; 1221 } 1222 1223 for (final Expression arg : args) { 1224 assert arg != null; 1225 loadExpressionUnbounded(arg); 1226 } 1227 return argCount; 1228 } 1229 1230 private boolean loadCallNode(final CallNode callNode, final TypeBounds resultBounds) { 1231 lineNumber(callNode.getLineNumber()); 1232 1233 final List<Expression> args = callNode.getArgs(); 1234 final Expression function = callNode.getFunction(); 1235 final Block currentBlock = lc.getCurrentBlock(); 1236 final CodeGeneratorLexicalContext codegenLexicalContext = lc; 1237 1238 function.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 1239 1240 private MethodEmitter sharedScopeCall(final IdentNode identNode, final int flags) { 1241 final Symbol symbol = identNode.getSymbol(); 1242 final boolean isFastScope = isFastScope(symbol); 1243 final int scopeCallFlags = flags | (isFastScope ? CALLSITE_FAST_SCOPE : 0); 1244 new OptimisticOperation(callNode, resultBounds) { 1245 @Override 1246 void loadStack() { 1247 method.loadCompilerConstant(SCOPE); 1248 if (isFastScope) { 1249 method.load(getScopeProtoDepth(currentBlock, symbol)); 1250 } else { 1251 method.load(-1); // Bypass fast-scope code in shared callsite 1252 } 1253 loadArgs(args); 1254 } 1255 @Override 1256 void consumeStack() { 1257 final Type[] paramTypes = method.getTypesFromStack(args.size()); 1258 // We have trouble finding e.g. in Type.typeFor(asm.Type) because it can't see the Context class 1259 // loader, so we need to weaken reference signatures to Object. 1260 for(int i = 0; i < paramTypes.length; ++i) { 1261 paramTypes[i] = Type.generic(paramTypes[i]); 1262 } 1263 // As shared scope calls are only used in non-optimistic compilation, we switch from using 1264 // TypeBounds to just a single definitive type, resultBounds.widest. 1265 final SharedScopeCall scopeCall = codegenLexicalContext.getScopeCall(unit, symbol, 1266 identNode.getType(), resultBounds.widest, paramTypes, scopeCallFlags); 1267 scopeCall.generateInvoke(method); 1268 } 1269 }.emit(); 1270 return method; 1271 } 1272 1273 private void scopeCall(final IdentNode ident, final int flags) { 1274 new OptimisticOperation(callNode, resultBounds) { 1275 int argsCount; 1276 @Override 1277 void loadStack() { 1278 loadExpressionAsObject(ident); // foo() makes no sense if foo == 3 1279 // ScriptFunction will see CALLSITE_SCOPE and will bind scope accordingly. 1280 method.loadUndefined(Type.OBJECT); //the 'this' 1281 argsCount = loadArgs(args); 1282 } 1283 @Override 1284 void consumeStack() { 1285 dynamicCall(2 + argsCount, flags); 1286 } 1287 }.emit(); 1288 } 1289 1290 private void evalCall(final IdentNode ident, final int flags) { 1291 final Label invoke_direct_eval = new Label("invoke_direct_eval"); 1292 final Label is_not_eval = new Label("is_not_eval"); 1293 final Label eval_done = new Label("eval_done"); 1294 1295 new OptimisticOperation(callNode, resultBounds) { 1296 int argsCount; 1297 @Override 1298 void loadStack() { 1299 /** 1300 * We want to load 'eval' to check if it is indeed global builtin eval. 1301 * If this eval call is inside a 'with' statement, dyn:getMethod|getProp|getElem 1302 * would be generated if ident is a "isFunction". But, that would result in a 1303 * bound function from WithObject. We don't want that as bound function as that 1304 * won't be detected as builtin eval. So, we make ident as "not a function" which 1305 * results in "dyn:getProp|getElem|getMethod" being generated and so WithObject 1306 * would return unbounded eval function. 1307 * 1308 * Example: 1309 * 1310 * var global = this; 1311 * function func() { 1312 * with({ eval: global.eval) { eval("var x = 10;") } 1313 * } 1314 */ 1315 loadExpressionAsObject(ident.setIsNotFunction()); // Type.OBJECT as foo() makes no sense if foo == 3 1316 globalIsEval(); 1317 method.ifeq(is_not_eval); 1318 1319 // Load up self (scope). 1320 method.loadCompilerConstant(SCOPE); 1321 final List<Expression> evalArgs = callNode.getEvalArgs().getArgs(); 1322 // load evaluated code 1323 loadExpressionAsObject(evalArgs.get(0)); 1324 // load second and subsequent args for side-effect 1325 final int numArgs = evalArgs.size(); 1326 for (int i = 1; i < numArgs; i++) { 1327 loadAndDiscard(evalArgs.get(i)); 1328 } 1329 method._goto(invoke_direct_eval); 1330 1331 method.label(is_not_eval); 1332 // load this time but with dyn:getMethod|getProp|getElem 1333 loadExpressionAsObject(ident); // Type.OBJECT as foo() makes no sense if foo == 3 1334 // This is some scope 'eval' or global eval replaced by user 1335 // but not the built-in ECMAScript 'eval' function call 1336 method.loadNull(); 1337 argsCount = loadArgs(callNode.getArgs()); 1338 } 1339 1340 @Override 1341 void consumeStack() { 1342 // Ordinary call 1343 dynamicCall(2 + argsCount, flags); 1344 method._goto(eval_done); 1345 1346 method.label(invoke_direct_eval); 1347 // Special/extra 'eval' arguments. These can be loaded late (in consumeStack) as we know none of 1348 // them can ever be optimistic. 1349 method.loadCompilerConstant(THIS); 1350 method.load(callNode.getEvalArgs().getLocation()); 1351 method.load(CodeGenerator.this.lc.getCurrentFunction().isStrict()); 1352 // direct call to Global.directEval 1353 globalDirectEval(); 1354 convertOptimisticReturnValue(); 1355 coerceStackTop(resultBounds); 1356 } 1357 }.emit(); 1358 1359 method.label(eval_done); 1360 } 1361 1362 @Override 1363 public boolean enterIdentNode(final IdentNode node) { 1364 final Symbol symbol = node.getSymbol(); 1365 1366 if (symbol.isScope()) { 1367 final int flags = getCallSiteFlags() | CALLSITE_SCOPE; 1368 final int useCount = symbol.getUseCount(); 1369 1370 // Threshold for generating shared scope callsite is lower for fast scope symbols because we know 1371 // we can dial in the correct scope. However, we also need to enable it for non-fast scopes to 1372 // support huge scripts like mandreel.js. 1373 if (callNode.isEval()) { 1374 evalCall(node, flags); 1375 } else if (useCount <= SharedScopeCall.FAST_SCOPE_CALL_THRESHOLD 1376 || !isFastScope(symbol) && useCount <= SharedScopeCall.SLOW_SCOPE_CALL_THRESHOLD 1377 || CodeGenerator.this.lc.inDynamicScope() 1378 || isOptimisticOrRestOf()) { 1379 scopeCall(node, flags); 1380 } else { 1381 sharedScopeCall(node, flags); 1382 } 1383 assert method.peekType().equals(resultBounds.within(callNode.getType())) : method.peekType() + " != " + resultBounds + "(" + callNode.getType() + ")"; 1384 } else { 1385 enterDefault(node); 1386 } 1387 1388 return false; 1389 } 1390 1391 @Override 1392 public boolean enterAccessNode(final AccessNode node) { 1393 //check if this is an apply to call node. only real applies, that haven't been 1394 //shadowed from their way to the global scope counts 1395 1396 //call nodes have program points. 1397 1398 final int flags = getCallSiteFlags() | (callNode.isApplyToCall() ? CALLSITE_APPLY_TO_CALL : 0); 1399 1400 new OptimisticOperation(callNode, resultBounds) { 1401 int argCount; 1402 @Override 1403 void loadStack() { 1404 loadExpressionAsObject(node.getBase()); 1405 method.dup(); 1406 // NOTE: not using a nested OptimisticOperation on this dynamicGet, as we expect to get back 1407 // a callable object. Nobody in their right mind would optimistically type this call site. 1408 assert !node.isOptimistic(); 1409 method.dynamicGet(node.getType(), node.getProperty(), flags, true); 1410 method.swap(); 1411 argCount = loadArgs(args); 1412 } 1413 @Override 1414 void consumeStack() { 1415 dynamicCall(2 + argCount, flags); 1416 } 1417 }.emit(); 1418 1419 return false; 1420 } 1421 1422 @Override 1423 public boolean enterFunctionNode(final FunctionNode origCallee) { 1424 new OptimisticOperation(callNode, resultBounds) { 1425 FunctionNode callee; 1426 int argsCount; 1427 @Override 1428 void loadStack() { 1429 callee = (FunctionNode)origCallee.accept(CodeGenerator.this); 1430 if (callee.isStrict()) { // "this" is undefined 1431 method.loadUndefined(Type.OBJECT); 1432 } else { // get global from scope (which is the self) 1433 globalInstance(); 1434 } 1435 argsCount = loadArgs(args); 1436 } 1437 1438 @Override 1439 void consumeStack() { 1440 final int flags = getCallSiteFlags(); 1441 //assert callNodeType.equals(callee.getReturnType()) : callNodeType + " != " + callee.getReturnType(); 1442 dynamicCall(2 + argsCount, flags); 1443 } 1444 }.emit(); 1445 return false; 1446 } 1447 1448 @Override 1449 public boolean enterIndexNode(final IndexNode node) { 1450 new OptimisticOperation(callNode, resultBounds) { 1451 int argsCount; 1452 @Override 1453 void loadStack() { 1454 loadExpressionAsObject(node.getBase()); 1455 method.dup(); 1456 final Type indexType = node.getIndex().getType(); 1457 if (indexType.isObject() || indexType.isBoolean()) { 1458 loadExpressionAsObject(node.getIndex()); //TODO boolean 1459 } else { 1460 loadExpressionUnbounded(node.getIndex()); 1461 } 1462 // NOTE: not using a nested OptimisticOperation on this dynamicGetIndex, as we expect to get 1463 // back a callable object. Nobody in their right mind would optimistically type this call site. 1464 assert !node.isOptimistic(); 1465 method.dynamicGetIndex(node.getType(), getCallSiteFlags(), true); 1466 method.swap(); 1467 argsCount = loadArgs(args); 1468 } 1469 @Override 1470 void consumeStack() { 1471 final int flags = getCallSiteFlags(); 1472 dynamicCall(2 + argsCount, flags); 1473 } 1474 }.emit(); 1475 return false; 1476 } 1477 1478 @Override 1479 protected boolean enterDefault(final Node node) { 1480 new OptimisticOperation(callNode, resultBounds) { 1481 int argsCount; 1482 @Override 1483 void loadStack() { 1484 // Load up function. 1485 loadExpressionAsObject(function); //TODO, e.g. booleans can be used as functions 1486 method.loadUndefined(Type.OBJECT); // ScriptFunction will figure out the correct this when it sees CALLSITE_SCOPE 1487 argsCount = loadArgs(args); 1488 } 1489 @Override 1490 void consumeStack() { 1491 final int flags = getCallSiteFlags() | CALLSITE_SCOPE; 1492 dynamicCall(2 + argsCount, flags); 1493 } 1494 }.emit(); 1495 return false; 1496 } 1497 }); 1498 1499 return false; 1500 } 1501 1502 /** 1503 * Returns the flags with optimistic flag and program point removed. 1504 * @param flags the flags that need optimism stripped from them. 1505 * @return flags without optimism 1506 */ 1507 static int nonOptimisticFlags(final int flags) { 1508 return flags & ~(CALLSITE_OPTIMISTIC | -1 << CALLSITE_PROGRAM_POINT_SHIFT); 1509 } 1510 1511 @Override 1512 public boolean enterContinueNode(final ContinueNode continueNode) { 1513 if(!method.isReachable()) { 1514 return false; 1515 } 1516 enterStatement(continueNode); 1517 method.beforeJoinPoint(continueNode); 1518 1519 final LoopNode continueTo = lc.getContinueTo(continueNode.getLabelName()); 1520 popScopesUntil(continueTo); 1521 final Label continueLabel = continueTo.getContinueLabel(); 1522 continueLabel.markAsBreakTarget(); 1523 method.splitAwareGoto(lc, continueLabel, continueTo); 1524 1525 return false; 1526 } 1527 1528 @Override 1529 public boolean enterEmptyNode(final EmptyNode emptyNode) { 1530 if(!method.isReachable()) { 1531 return false; 1532 } 1533 enterStatement(emptyNode); 1534 1535 return false; 1536 } 1537 1538 @Override 1539 public boolean enterExpressionStatement(final ExpressionStatement expressionStatement) { 1540 if(!method.isReachable()) { 1541 return false; 1542 } 1543 enterStatement(expressionStatement); 1544 1545 loadAndDiscard(expressionStatement.getExpression()); 1546 assert method.getStackSize() == 0; 1547 1548 return false; 1549 } 1550 1551 @Override 1552 public boolean enterBlockStatement(final BlockStatement blockStatement) { 1553 if(!method.isReachable()) { 1554 return false; 1555 } 1556 enterStatement(blockStatement); 1557 1558 blockStatement.getBlock().accept(this); 1559 1560 return false; 1561 } 1562 1563 @Override 1564 public boolean enterForNode(final ForNode forNode) { 1565 if(!method.isReachable()) { 1566 return false; 1567 } 1568 enterStatement(forNode); 1569 if (forNode.isForIn()) { 1570 enterForIn(forNode); 1571 } else { 1572 final Expression init = forNode.getInit(); 1573 if (init != null) { 1574 loadAndDiscard(init); 1575 } 1576 enterForOrWhile(forNode, forNode.getModify()); 1577 } 1578 1579 return false; 1580 } 1581 1582 private void enterForIn(final ForNode forNode) { 1583 loadExpression(forNode.getModify(), TypeBounds.OBJECT); 1584 method.invoke(forNode.isForEach() ? ScriptRuntime.TO_VALUE_ITERATOR : ScriptRuntime.TO_PROPERTY_ITERATOR); 1585 final Symbol iterSymbol = forNode.getIterator(); 1586 final int iterSlot = iterSymbol.getSlot(Type.OBJECT); 1587 method.store(iterSymbol, ITERATOR_TYPE); 1588 1589 method.beforeJoinPoint(forNode); 1590 1591 final Label continueLabel = forNode.getContinueLabel(); 1592 final Label breakLabel = forNode.getBreakLabel(); 1593 1594 method.label(continueLabel); 1595 method.load(ITERATOR_TYPE, iterSlot); 1596 method.invoke(interfaceCallNoLookup(ITERATOR_CLASS, "hasNext", boolean.class)); 1597 final JoinPredecessorExpression test = forNode.getTest(); 1598 final Block body = forNode.getBody(); 1599 if(LocalVariableConversion.hasLiveConversion(test)) { 1600 final Label afterConversion = new Label("for_in_after_test_conv"); 1601 method.ifne(afterConversion); 1602 method.beforeJoinPoint(test); 1603 method._goto(breakLabel); 1604 method.label(afterConversion); 1605 } else { 1606 method.ifeq(breakLabel); 1607 } 1608 1609 new Store<Expression>(forNode.getInit()) { 1610 @Override 1611 protected void storeNonDiscard() { 1612 // This expression is neither part of a discard, nor needs to be left on the stack after it was 1613 // stored, so we override storeNonDiscard to be a no-op. 1614 } 1615 1616 @Override 1617 protected void evaluate() { 1618 method.load(ITERATOR_TYPE, iterSlot); 1619 // TODO: optimistic for-in iteration 1620 method.invoke(interfaceCallNoLookup(ITERATOR_CLASS, "next", Object.class)); 1621 } 1622 }.store(); 1623 body.accept(this); 1624 1625 if(method.isReachable()) { 1626 method._goto(continueLabel); 1627 } 1628 method.label(breakLabel); 1629 } 1630 1631 /** 1632 * Initialize the slots in a frame to undefined. 1633 * 1634 * @param block block with local vars. 1635 */ 1636 private void initLocals(final Block block) { 1637 lc.onEnterBlock(block); 1638 1639 final boolean isFunctionBody = lc.isFunctionBody(); 1640 final FunctionNode function = lc.getCurrentFunction(); 1641 if (isFunctionBody) { 1642 initializeMethodParameters(function); 1643 if(!function.isVarArg()) { 1644 expandParameterSlots(function); 1645 } 1646 if (method.hasScope()) { 1647 if (function.needsParentScope()) { 1648 method.loadCompilerConstant(CALLEE); 1649 method.invoke(ScriptFunction.GET_SCOPE); 1650 } else { 1651 assert function.hasScopeBlock(); 1652 method.loadNull(); 1653 } 1654 method.storeCompilerConstant(SCOPE); 1655 } 1656 if (function.needsArguments()) { 1657 initArguments(function); 1658 } 1659 } 1660 1661 /* 1662 * Determine if block needs scope, if not, just do initSymbols for this block. 1663 */ 1664 if (block.needsScope()) { 1665 /* 1666 * Determine if function is varargs and consequently variables have to 1667 * be in the scope. 1668 */ 1669 final boolean varsInScope = function.allVarsInScope(); 1670 1671 // TODO for LET we can do better: if *block* does not contain any eval/with, we don't need its vars in scope. 1672 1673 final boolean hasArguments = function.needsArguments(); 1674 final List<MapTuple<Symbol>> tuples = new ArrayList<>(); 1675 final Iterator<IdentNode> paramIter = function.getParameters().iterator(); 1676 for (final Symbol symbol : block.getSymbols()) { 1677 if (symbol.isInternal() || symbol.isThis()) { 1678 continue; 1679 } 1680 1681 if (symbol.isVar()) { 1682 assert !varsInScope || symbol.isScope(); 1683 if (varsInScope || symbol.isScope()) { 1684 assert symbol.isScope() : "scope for " + symbol + " should have been set in Lower already " + function.getName(); 1685 assert !symbol.hasSlot() : "slot for " + symbol + " should have been removed in Lower already" + function.getName(); 1686 1687 //this tuple will not be put fielded, as it has no value, just a symbol 1688 tuples.add(new MapTuple<Symbol>(symbol.getName(), symbol, null)); 1689 } else { 1690 assert symbol.hasSlot() || symbol.slotCount() == 0 : symbol + " should have a slot only, no scope"; 1691 } 1692 } else if (symbol.isParam() && (varsInScope || hasArguments || symbol.isScope())) { 1693 assert symbol.isScope() : "scope for " + symbol + " should have been set in AssignSymbols already " + function.getName() + " varsInScope="+varsInScope+" hasArguments="+hasArguments+" symbol.isScope()=" + symbol.isScope(); 1694 assert !(hasArguments && symbol.hasSlot()) : "slot for " + symbol + " should have been removed in Lower already " + function.getName(); 1695 1696 final Type paramType; 1697 final Symbol paramSymbol; 1698 1699 if (hasArguments) { 1700 assert !symbol.hasSlot() : "slot for " + symbol + " should have been removed in Lower already "; 1701 paramSymbol = null; 1702 paramType = null; 1703 } else { 1704 paramSymbol = symbol; 1705 // NOTE: We're relying on the fact here that Block.symbols is a LinkedHashMap, hence it will 1706 // return symbols in the order they were defined, and parameters are defined in the same order 1707 // they appear in the function. That's why we can have a single pass over the parameter list 1708 // with an iterator, always just scanning forward for the next parameter that matches the symbol 1709 // name. 1710 for(;;) { 1711 final IdentNode nextParam = paramIter.next(); 1712 if(nextParam.getName().equals(symbol.getName())) { 1713 paramType = nextParam.getType(); 1714 break; 1715 } 1716 } 1717 } 1718 1719 tuples.add(new MapTuple<Symbol>(symbol.getName(), symbol, paramType, paramSymbol) { 1720 //this symbol will be put fielded, we can't initialize it as undefined with a known type 1721 @Override 1722 public Class<?> getValueType() { 1723 if (OBJECT_FIELDS_ONLY || value == null || paramType == null) { 1724 return Object.class; 1725 } 1726 return paramType.isBoolean() ? Object.class : paramType.getTypeClass(); 1727 } 1728 }); 1729 } 1730 } 1731 1732 /* 1733 * Create a new object based on the symbols and values, generate 1734 * bootstrap code for object 1735 */ 1736 new FieldObjectCreator<Symbol>(this, tuples, true, hasArguments) { 1737 @Override 1738 protected void loadValue(final Symbol value, final Type type) { 1739 method.load(value, type); 1740 } 1741 }.makeObject(method); 1742 // program function: merge scope into global 1743 if (isFunctionBody && function.isProgram()) { 1744 method.invoke(ScriptRuntime.MERGE_SCOPE); 1745 } 1746 1747 method.storeCompilerConstant(SCOPE); 1748 if(!isFunctionBody) { 1749 // Function body doesn't need a try/catch to restore scope, as it'd be a dead store anyway. Allowing it 1750 // actually causes issues with UnwarrantedOptimismException handlers as ASM will sort this handler to 1751 // the top of the exception handler table, so it'll be triggered instead of the UOE handlers. 1752 final Label scopeEntryLabel = new Label("scope_entry"); 1753 scopeEntryLabels.push(scopeEntryLabel); 1754 method.label(scopeEntryLabel); 1755 } 1756 } else if (isFunctionBody && function.isVarArg()) { 1757 // Since we don't have a scope, parameters didn't get assigned array indices by the FieldObjectCreator, so 1758 // we need to assign them separately here. 1759 int nextParam = 0; 1760 for (final IdentNode param : function.getParameters()) { 1761 param.getSymbol().setFieldIndex(nextParam++); 1762 } 1763 } 1764 1765 // Debugging: print symbols? @see --print-symbols flag 1766 printSymbols(block, function, (isFunctionBody ? "Function " : "Block in ") + (function.getIdent() == null ? "<anonymous>" : function.getIdent().getName())); 1767 } 1768 1769 /** 1770 * Incoming method parameters are always declared on method entry; declare them in the local variable table. 1771 * @param function function for which code is being generated. 1772 */ 1773 private void initializeMethodParameters(final FunctionNode function) { 1774 final Label functionStart = new Label("fn_start"); 1775 method.label(functionStart); 1776 int nextSlot = 0; 1777 if(function.needsCallee()) { 1778 initializeInternalFunctionParameter(CALLEE, function, functionStart, nextSlot++); 1779 } 1780 initializeInternalFunctionParameter(THIS, function, functionStart, nextSlot++); 1781 if(function.isVarArg()) { 1782 initializeInternalFunctionParameter(VARARGS, function, functionStart, nextSlot++); 1783 } else { 1784 for(final IdentNode param: function.getParameters()) { 1785 final Symbol symbol = param.getSymbol(); 1786 if(symbol.isBytecodeLocal()) { 1787 method.initializeMethodParameter(symbol, param.getType(), functionStart); 1788 } 1789 } 1790 } 1791 } 1792 1793 private void initializeInternalFunctionParameter(final CompilerConstants cc, final FunctionNode fn, final Label functionStart, final int slot) { 1794 final Symbol symbol = initializeInternalFunctionOrSplitParameter(cc, fn, functionStart, slot); 1795 // Internal function params (:callee, this, and :varargs) are never expanded to multiple slots 1796 assert symbol.getFirstSlot() == slot; 1797 } 1798 1799 private Symbol initializeInternalFunctionOrSplitParameter(final CompilerConstants cc, final FunctionNode fn, final Label functionStart, final int slot) { 1800 final Symbol symbol = fn.getBody().getExistingSymbol(cc.symbolName()); 1801 final Type type = Type.typeFor(cc.type()); 1802 method.initializeMethodParameter(symbol, type, functionStart); 1803 method.onLocalStore(type, slot); 1804 return symbol; 1805 } 1806 1807 /** 1808 * Parameters come into the method packed into local variable slots next to each other. Nashorn on the other hand 1809 * can use 1-6 slots for a local variable depending on all the types it needs to store. When this method is invoked, 1810 * the symbols are already allocated such wider slots, but the values are still in tightly packed incoming slots, 1811 * and we need to spread them into their new locations. 1812 * @param function the function for which parameter-spreading code needs to be emitted 1813 */ 1814 private void expandParameterSlots(final FunctionNode function) { 1815 final List<IdentNode> parameters = function.getParameters(); 1816 // Calculate the total number of incoming parameter slots 1817 int currentIncomingSlot = function.needsCallee() ? 2 : 1; 1818 for(final IdentNode parameter: parameters) { 1819 currentIncomingSlot += parameter.getType().getSlots(); 1820 } 1821 // Starting from last parameter going backwards, move the parameter values into their new slots. 1822 for(int i = parameters.size(); i-- > 0;) { 1823 final IdentNode parameter = parameters.get(i); 1824 final Type parameterType = parameter.getType(); 1825 final int typeWidth = parameterType.getSlots(); 1826 currentIncomingSlot -= typeWidth; 1827 final Symbol symbol = parameter.getSymbol(); 1828 final int slotCount = symbol.slotCount(); 1829 assert slotCount > 0; 1830 // Scoped parameters must not hold more than one value 1831 assert symbol.isBytecodeLocal() || slotCount == typeWidth; 1832 1833 // Mark it as having its value stored into it by the method invocation. 1834 method.onLocalStore(parameterType, currentIncomingSlot); 1835 if(currentIncomingSlot != symbol.getSlot(parameterType)) { 1836 method.load(parameterType, currentIncomingSlot); 1837 method.store(symbol, parameterType); 1838 } 1839 } 1840 } 1841 1842 private void initArguments(final FunctionNode function) { 1843 method.loadCompilerConstant(VARARGS); 1844 if (function.needsCallee()) { 1845 method.loadCompilerConstant(CALLEE); 1846 } else { 1847 // If function is strict mode, "arguments.callee" is not populated, so we don't necessarily need the 1848 // caller. 1849 assert function.isStrict(); 1850 method.loadNull(); 1851 } 1852 method.load(function.getParameters().size()); 1853 globalAllocateArguments(); 1854 method.storeCompilerConstant(ARGUMENTS); 1855 } 1856 1857 private boolean skipFunction(final FunctionNode functionNode) { 1858 final ScriptEnvironment env = compiler.getScriptEnvironment(); 1859 final boolean lazy = env._lazy_compilation; 1860 final boolean onDemand = compiler.isOnDemandCompilation(); 1861 1862 // If this is on-demand or lazy compilation, don't compile a nested (not topmost) function. 1863 if((onDemand || lazy) && lc.getOutermostFunction() != functionNode) { 1864 return true; 1865 } 1866 1867 // If lazy compiling with optimistic types, don't compile the program eagerly either. It will soon be 1868 // invalidated anyway. In presence of a class cache, this further means that an obsoleted program version 1869 // lingers around. Also, currently loading previously persisted optimistic types information only works if 1870 // we're on-demand compiling a function, so with this strategy the :program method can also have the warmup 1871 // benefit of using previously persisted types. 1872 // 1873 // NOTE that this means the first compiled class will effectively just have a :createProgramFunction method, and 1874 // the RecompilableScriptFunctionData (RSFD) object in its constants array. It won't even have the :program 1875 // method. This is by design. It does mean that we're wasting one compiler execution (and we could minimize this 1876 // by just running it up to scope depth calculation, which creates the RSFDs and then this limited codegen). 1877 // We could emit an initial separate compile unit with the initial version of :program in it to better utilize 1878 // the compilation pipeline, but that would need more invasive changes, as currently the assumption that 1879 // :program is emitted into the first compilation unit of the function lives in many places. 1880 return !onDemand && lazy && env._optimistic_types && functionNode.isProgram(); 1881 } 1882 1883 @Override 1884 public boolean enterFunctionNode(final FunctionNode functionNode) { 1885 final int fnId = functionNode.getId(); 1886 1887 if (skipFunction(functionNode)) { 1888 // In case we are not generating code for the function, we must create or retrieve the function object and 1889 // load it on the stack here. 1890 newFunctionObject(functionNode, false); 1891 return false; 1892 } 1893 1894 final String fnName = functionNode.getName(); 1895 1896 // NOTE: we only emit the method for a function with the given name once. We can have multiple functions with 1897 // the same name as a result of inlining finally blocks. However, in the future -- with type specialization, 1898 // notably -- we might need to check for both name *and* signature. Of course, even that might not be 1899 // sufficient; the function might have a code dependency on the type of the variables in its enclosing scopes, 1900 // and the type of such a variable can be different in catch and finally blocks. So, in the future we will have 1901 // to decide to either generate a unique method for each inlined copy of the function, maybe figure out its 1902 // exact type closure and deduplicate based on that, or just decide that functions in finally blocks aren't 1903 // worth it, and generate one method with most generic type closure. 1904 if (!emittedMethods.contains(fnName)) { 1905 log.info("=== BEGIN ", fnName); 1906 1907 assert functionNode.getCompileUnit() != null : "no compile unit for " + fnName + " " + Debug.id(functionNode); 1908 unit = lc.pushCompileUnit(functionNode.getCompileUnit()); 1909 assert lc.hasCompileUnits(); 1910 1911 final ClassEmitter classEmitter = unit.getClassEmitter(); 1912 pushMethodEmitter(isRestOf() ? classEmitter.restOfMethod(functionNode) : classEmitter.method(functionNode)); 1913 method.setPreventUndefinedLoad(); 1914 if(useOptimisticTypes()) { 1915 lc.pushUnwarrantedOptimismHandlers(); 1916 } 1917 1918 // new method - reset last line number 1919 lastLineNumber = -1; 1920 1921 method.begin(); 1922 1923 if (isRestOf()) { 1924 final ContinuationInfo ci = new ContinuationInfo(); 1925 fnIdToContinuationInfo.put(fnId, ci); 1926 method.gotoLoopStart(ci.getHandlerLabel()); 1927 } 1928 } 1929 1930 return true; 1931 } 1932 1933 private void pushMethodEmitter(final MethodEmitter newMethod) { 1934 method = lc.pushMethodEmitter(newMethod); 1935 catchLabels.push(METHOD_BOUNDARY); 1936 } 1937 1938 private void popMethodEmitter() { 1939 method = lc.popMethodEmitter(method); 1940 assert catchLabels.peek() == METHOD_BOUNDARY; 1941 catchLabels.pop(); 1942 } 1943 1944 @Override 1945 public Node leaveFunctionNode(final FunctionNode functionNode) { 1946 try { 1947 final boolean markOptimistic; 1948 if (emittedMethods.add(functionNode.getName())) { 1949 markOptimistic = generateUnwarrantedOptimismExceptionHandlers(functionNode); 1950 generateContinuationHandler(); 1951 method.end(); // wrap up this method 1952 unit = lc.popCompileUnit(functionNode.getCompileUnit()); 1953 popMethodEmitter(); 1954 log.info("=== END ", functionNode.getName()); 1955 } else { 1956 markOptimistic = false; 1957 } 1958 1959 FunctionNode newFunctionNode = functionNode.setState(lc, CompilationState.BYTECODE_GENERATED); 1960 if (markOptimistic) { 1961 newFunctionNode = newFunctionNode.setFlag(lc, FunctionNode.IS_DEOPTIMIZABLE); 1962 } 1963 1964 newFunctionObject(newFunctionNode, true); 1965 return newFunctionNode; 1966 } catch (final Throwable t) { 1967 Context.printStackTrace(t); 1968 final VerifyError e = new VerifyError("Code generation bug in \"" + functionNode.getName() + "\": likely stack misaligned: " + t + " " + functionNode.getSource().getName()); 1969 e.initCause(t); 1970 throw e; 1971 } 1972 } 1973 1974 @Override 1975 public boolean enterIfNode(final IfNode ifNode) { 1976 if(!method.isReachable()) { 1977 return false; 1978 } 1979 enterStatement(ifNode); 1980 1981 final Expression test = ifNode.getTest(); 1982 final Block pass = ifNode.getPass(); 1983 final Block fail = ifNode.getFail(); 1984 final boolean hasFailConversion = LocalVariableConversion.hasLiveConversion(ifNode); 1985 1986 final Label failLabel = new Label("if_fail"); 1987 final Label afterLabel = (fail == null && !hasFailConversion) ? null : new Label("if_done"); 1988 1989 emitBranch(test, failLabel, false); 1990 1991 pass.accept(this); 1992 if(method.isReachable() && afterLabel != null) { 1993 method._goto(afterLabel); //don't fallthru to fail block 1994 } 1995 method.label(failLabel); 1996 1997 if (fail != null) { 1998 fail.accept(this); 1999 } else if(hasFailConversion) { 2000 method.beforeJoinPoint(ifNode); 2001 } 2002 2003 if(afterLabel != null) { 2004 method.label(afterLabel); 2005 } 2006 2007 return false; 2008 } 2009 2010 private void emitBranch(final Expression test, final Label label, final boolean jumpWhenTrue) { 2011 new BranchOptimizer(this, method).execute(test, label, jumpWhenTrue); 2012 } 2013 2014 private void enterStatement(final Statement statement) { 2015 lineNumber(statement); 2016 } 2017 2018 private void lineNumber(final Statement statement) { 2019 lineNumber(statement.getLineNumber()); 2020 } 2021 2022 private void lineNumber(final int lineNumber) { 2023 if (lineNumber != lastLineNumber) { 2024 method.lineNumber(lineNumber); 2025 } 2026 lastLineNumber = lineNumber; 2027 } 2028 2029 int getLastLineNumber() { 2030 return lastLineNumber; 2031 } 2032 2033 /** 2034 * Load a list of nodes as an array of a specific type 2035 * The array will contain the visited nodes. 2036 * 2037 * @param arrayLiteralNode the array of contents 2038 * @param arrayType the type of the array, e.g. ARRAY_NUMBER or ARRAY_OBJECT 2039 * 2040 * @return the method generator that was used 2041 */ 2042 private MethodEmitter loadArray(final ArrayLiteralNode arrayLiteralNode, final ArrayType arrayType) { 2043 assert arrayType == Type.INT_ARRAY || arrayType == Type.LONG_ARRAY || arrayType == Type.NUMBER_ARRAY || arrayType == Type.OBJECT_ARRAY; 2044 2045 final Expression[] nodes = arrayLiteralNode.getValue(); 2046 final Object presets = arrayLiteralNode.getPresets(); 2047 final int[] postsets = arrayLiteralNode.getPostsets(); 2048 final Class<?> type = arrayType.getTypeClass(); 2049 final List<ArrayUnit> units = arrayLiteralNode.getUnits(); 2050 2051 loadConstant(presets); 2052 2053 final Type elementType = arrayType.getElementType(); 2054 2055 if (units != null) { 2056 final MethodEmitter savedMethod = method; 2057 final FunctionNode currentFunction = lc.getCurrentFunction(); 2058 2059 for (final ArrayUnit arrayUnit : units) { 2060 unit = lc.pushCompileUnit(arrayUnit.getCompileUnit()); 2061 2062 final String className = unit.getUnitClassName(); 2063 assert unit != null; 2064 final String name = currentFunction.uniqueName(SPLIT_PREFIX.symbolName()); 2065 final String signature = methodDescriptor(type, ScriptFunction.class, Object.class, ScriptObject.class, type); 2066 2067 pushMethodEmitter(unit.getClassEmitter().method(EnumSet.of(Flag.PUBLIC, Flag.STATIC), name, signature)); 2068 2069 method.setFunctionNode(currentFunction); 2070 method.begin(); 2071 2072 defineCommonSplitMethodParameters(); 2073 defineSplitMethodParameter(3, arrayType); 2074 2075 fixScopeSlot(currentFunction); 2076 2077 lc.enterSplitNode(); 2078 2079 final int arraySlot = SPLIT_ARRAY_ARG.slot(); 2080 for (int i = arrayUnit.getLo(); i < arrayUnit.getHi(); i++) { 2081 method.load(arrayType, arraySlot); 2082 storeElement(nodes, elementType, postsets[i]); 2083 } 2084 2085 method.load(arrayType, arraySlot); 2086 method._return(); 2087 lc.exitSplitNode(); 2088 method.end(); 2089 lc.releaseSlots(); 2090 popMethodEmitter(); 2091 2092 assert method == savedMethod; 2093 method.loadCompilerConstant(CALLEE); 2094 method.swap(); 2095 method.loadCompilerConstant(THIS); 2096 method.swap(); 2097 method.loadCompilerConstant(SCOPE); 2098 method.swap(); 2099 method.invokestatic(className, name, signature); 2100 2101 unit = lc.popCompileUnit(unit); 2102 } 2103 2104 return method; 2105 } 2106 2107 if(postsets.length > 0) { 2108 final int arraySlot = method.getUsedSlotsWithLiveTemporaries(); 2109 method.storeTemp(arrayType, arraySlot); 2110 for (final int postset : postsets) { 2111 method.load(arrayType, arraySlot); 2112 storeElement(nodes, elementType, postset); 2113 } 2114 method.load(arrayType, arraySlot); 2115 } 2116 return method; 2117 } 2118 2119 private void storeElement(final Expression[] nodes, final Type elementType, final int index) { 2120 method.load(index); 2121 2122 final Expression element = nodes[index]; 2123 2124 if (element == null) { 2125 method.loadEmpty(elementType); 2126 } else { 2127 loadExpressionAsType(element, elementType); 2128 } 2129 2130 method.arraystore(); 2131 } 2132 2133 private MethodEmitter loadArgsArray(final List<Expression> args) { 2134 final Object[] array = new Object[args.size()]; 2135 loadConstant(array); 2136 2137 for (int i = 0; i < args.size(); i++) { 2138 method.dup(); 2139 method.load(i); 2140 loadExpression(args.get(i), TypeBounds.OBJECT); // variable arity methods always take objects 2141 method.arraystore(); 2142 } 2143 2144 return method; 2145 } 2146 2147 /** 2148 * Load a constant from the constant array. This is only public to be callable from the objects 2149 * subpackage. Do not call directly. 2150 * 2151 * @param string string to load 2152 */ 2153 void loadConstant(final String string) { 2154 final String unitClassName = unit.getUnitClassName(); 2155 final ClassEmitter classEmitter = unit.getClassEmitter(); 2156 final int index = compiler.getConstantData().add(string); 2157 2158 method.load(index); 2159 method.invokestatic(unitClassName, GET_STRING.symbolName(), methodDescriptor(String.class, int.class)); 2160 classEmitter.needGetConstantMethod(String.class); 2161 } 2162 2163 /** 2164 * Load a constant from the constant array. This is only public to be callable from the objects 2165 * subpackage. Do not call directly. 2166 * 2167 * @param object object to load 2168 */ 2169 void loadConstant(final Object object) { 2170 loadConstant(object, unit, method); 2171 } 2172 2173 private void loadConstant(final Object object, final CompileUnit compileUnit, final MethodEmitter methodEmitter) { 2174 final String unitClassName = compileUnit.getUnitClassName(); 2175 final ClassEmitter classEmitter = compileUnit.getClassEmitter(); 2176 final int index = compiler.getConstantData().add(object); 2177 final Class<?> cls = object.getClass(); 2178 2179 if (cls == PropertyMap.class) { 2180 methodEmitter.load(index); 2181 methodEmitter.invokestatic(unitClassName, GET_MAP.symbolName(), methodDescriptor(PropertyMap.class, int.class)); 2182 classEmitter.needGetConstantMethod(PropertyMap.class); 2183 } else if (cls.isArray()) { 2184 methodEmitter.load(index); 2185 final String methodName = ClassEmitter.getArrayMethodName(cls); 2186 methodEmitter.invokestatic(unitClassName, methodName, methodDescriptor(cls, int.class)); 2187 classEmitter.needGetConstantMethod(cls); 2188 } else { 2189 methodEmitter.loadConstants().load(index).arrayload(); 2190 if (object instanceof ArrayData) { 2191 // avoid cast to non-public ArrayData subclass 2192 methodEmitter.checkcast(ArrayData.class); 2193 methodEmitter.invoke(virtualCallNoLookup(ArrayData.class, "copy", ArrayData.class)); 2194 } else if (cls != Object.class) { 2195 methodEmitter.checkcast(cls); 2196 } 2197 } 2198 } 2199 2200 // literal values 2201 private void loadLiteral(final LiteralNode<?> node, final TypeBounds resultBounds) { 2202 final Object value = node.getValue(); 2203 2204 if (value == null) { 2205 method.loadNull(); 2206 } else if (value instanceof Undefined) { 2207 method.loadUndefined(resultBounds.within(Type.OBJECT)); 2208 } else if (value instanceof String) { 2209 final String string = (String)value; 2210 2211 if (string.length() > MethodEmitter.LARGE_STRING_THRESHOLD / 3) { // 3 == max bytes per encoded char 2212 loadConstant(string); 2213 } else { 2214 method.load(string); 2215 } 2216 } else if (value instanceof RegexToken) { 2217 loadRegex((RegexToken)value); 2218 } else if (value instanceof Boolean) { 2219 method.load((Boolean)value); 2220 } else if (value instanceof Integer) { 2221 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) { 2222 method.load((Integer)value); 2223 method.convert(Type.OBJECT); 2224 } else if(!resultBounds.canBeNarrowerThan(Type.NUMBER)) { 2225 method.load(((Integer)value).doubleValue()); 2226 } else if(!resultBounds.canBeNarrowerThan(Type.LONG)) { 2227 method.load(((Integer)value).longValue()); 2228 } else { 2229 method.load((Integer)value); 2230 } 2231 } else if (value instanceof Long) { 2232 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) { 2233 method.load((Long)value); 2234 method.convert(Type.OBJECT); 2235 } else if(!resultBounds.canBeNarrowerThan(Type.NUMBER)) { 2236 method.load(((Long)value).doubleValue()); 2237 } else { 2238 method.load((Long)value); 2239 } 2240 } else if (value instanceof Double) { 2241 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) { 2242 method.load((Double)value); 2243 method.convert(Type.OBJECT); 2244 } else { 2245 method.load((Double)value); 2246 } 2247 } else if (node instanceof ArrayLiteralNode) { 2248 final ArrayLiteralNode arrayLiteral = (ArrayLiteralNode)node; 2249 final ArrayType atype = arrayLiteral.getArrayType(); 2250 loadArray(arrayLiteral, atype); 2251 globalAllocateArray(atype); 2252 } else { 2253 throw new UnsupportedOperationException("Unknown literal for " + node.getClass() + " " + value.getClass() + " " + value); 2254 } 2255 } 2256 2257 private MethodEmitter loadRegexToken(final RegexToken value) { 2258 method.load(value.getExpression()); 2259 method.load(value.getOptions()); 2260 return globalNewRegExp(); 2261 } 2262 2263 private MethodEmitter loadRegex(final RegexToken regexToken) { 2264 if (regexFieldCount > MAX_REGEX_FIELDS) { 2265 return loadRegexToken(regexToken); 2266 } 2267 // emit field 2268 final String regexName = lc.getCurrentFunction().uniqueName(REGEX_PREFIX.symbolName()); 2269 final ClassEmitter classEmitter = unit.getClassEmitter(); 2270 2271 classEmitter.field(EnumSet.of(PRIVATE, STATIC), regexName, Object.class); 2272 regexFieldCount++; 2273 2274 // get field, if null create new regex, finally clone regex object 2275 method.getStatic(unit.getUnitClassName(), regexName, typeDescriptor(Object.class)); 2276 method.dup(); 2277 final Label cachedLabel = new Label("cached"); 2278 method.ifnonnull(cachedLabel); 2279 2280 method.pop(); 2281 loadRegexToken(regexToken); 2282 method.dup(); 2283 method.putStatic(unit.getUnitClassName(), regexName, typeDescriptor(Object.class)); 2284 2285 method.label(cachedLabel); 2286 globalRegExpCopy(); 2287 2288 return method; 2289 } 2290 2291 /** 2292 * Check if a property value contains a particular program point 2293 * @param value value 2294 * @param pp program point 2295 * @return true if it's there. 2296 */ 2297 private static boolean propertyValueContains(final Expression value, final int pp) { 2298 return new Supplier<Boolean>() { 2299 boolean contains; 2300 2301 @Override 2302 public Boolean get() { 2303 value.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 2304 @Override 2305 public boolean enterFunctionNode(final FunctionNode functionNode) { 2306 return false; 2307 } 2308 2309 @Override 2310 public boolean enterObjectNode(final ObjectNode objectNode) { 2311 return false; 2312 } 2313 2314 @Override 2315 public boolean enterDefault(final Node node) { 2316 if (contains) { 2317 return false; 2318 } 2319 if (node instanceof Optimistic && ((Optimistic)node).getProgramPoint() == pp) { 2320 contains = true; 2321 return false; 2322 } 2323 return true; 2324 } 2325 }); 2326 2327 return contains; 2328 } 2329 }.get(); 2330 } 2331 2332 private void loadObjectNode(final ObjectNode objectNode) { 2333 final List<PropertyNode> elements = objectNode.getElements(); 2334 2335 final List<MapTuple<Expression>> tuples = new ArrayList<>(); 2336 final List<PropertyNode> gettersSetters = new ArrayList<>(); 2337 final int ccp = getCurrentContinuationEntryPoint(); 2338 2339 Expression protoNode = null; 2340 boolean restOfProperty = false; 2341 2342 for (final PropertyNode propertyNode : elements) { 2343 final Expression value = propertyNode.getValue(); 2344 final String key = propertyNode.getKeyName(); 2345 // Just use a pseudo-symbol. We just need something non null; use the name and zero flags. 2346 final Symbol symbol = value == null ? null : new Symbol(key, 0); 2347 2348 if (value == null) { 2349 gettersSetters.add(propertyNode); 2350 } else if (propertyNode.getKey() instanceof IdentNode && 2351 key.equals(ScriptObject.PROTO_PROPERTY_NAME)) { 2352 // ES6 draft compliant __proto__ inside object literal 2353 // Identifier key and name is __proto__ 2354 protoNode = value; 2355 continue; 2356 } 2357 2358 restOfProperty |= 2359 value != null && 2360 isValid(ccp) && 2361 propertyValueContains(value, ccp); 2362 2363 //for literals, a value of null means object type, i.e. the value null or getter setter function 2364 //(I think) 2365 final Class<?> valueType = (OBJECT_FIELDS_ONLY || value == null || value.getType().isBoolean()) ? Object.class : value.getType().getTypeClass(); 2366 tuples.add(new MapTuple<Expression>(key, symbol, Type.typeFor(valueType), value) { 2367 @Override 2368 public Class<?> getValueType() { 2369 return type.getTypeClass(); 2370 } 2371 }); 2372 } 2373 2374 final ObjectCreator<?> oc; 2375 if (elements.size() > OBJECT_SPILL_THRESHOLD) { 2376 oc = new SpillObjectCreator(this, tuples); 2377 } else { 2378 oc = new FieldObjectCreator<Expression>(this, tuples) { 2379 @Override 2380 protected void loadValue(final Expression node, final Type type) { 2381 loadExpressionAsType(node, type); 2382 }}; 2383 } 2384 oc.makeObject(method); 2385 2386 //if this is a rest of method and our continuation point was found as one of the values 2387 //in the properties above, we need to reset the map to oc.getMap() in the continuation 2388 //handler 2389 if (restOfProperty) { 2390 final ContinuationInfo ci = getContinuationInfo(); 2391 // Can be set at most once for a single rest-of method 2392 assert ci.getObjectLiteralMap() == null; 2393 ci.setObjectLiteralMap(oc.getMap()); 2394 ci.setObjectLiteralStackDepth(method.getStackSize()); 2395 } 2396 2397 method.dup(); 2398 if (protoNode != null) { 2399 loadExpressionAsObject(protoNode); 2400 // take care of { __proto__: 34 } or some such! 2401 method.convert(Type.OBJECT); 2402 method.invoke(ScriptObject.SET_PROTO_FROM_LITERAL); 2403 } else { 2404 method.invoke(ScriptObject.SET_GLOBAL_OBJECT_PROTO); 2405 } 2406 2407 for (final PropertyNode propertyNode : gettersSetters) { 2408 final FunctionNode getter = propertyNode.getGetter(); 2409 final FunctionNode setter = propertyNode.getSetter(); 2410 2411 assert getter != null || setter != null; 2412 2413 method.dup().loadKey(propertyNode.getKey()); 2414 if (getter == null) { 2415 method.loadNull(); 2416 } else { 2417 getter.accept(this); 2418 } 2419 2420 if (setter == null) { 2421 method.loadNull(); 2422 } else { 2423 setter.accept(this); 2424 } 2425 2426 method.invoke(ScriptObject.SET_USER_ACCESSORS); 2427 } 2428 } 2429 2430 @Override 2431 public boolean enterReturnNode(final ReturnNode returnNode) { 2432 if(!method.isReachable()) { 2433 return false; 2434 } 2435 enterStatement(returnNode); 2436 2437 method.registerReturn(); 2438 2439 final Type returnType = lc.getCurrentFunction().getReturnType(); 2440 2441 final Expression expression = returnNode.getExpression(); 2442 if (expression != null) { 2443 loadExpressionUnbounded(expression); 2444 } else { 2445 method.loadUndefined(returnType); 2446 } 2447 2448 method._return(returnType); 2449 2450 return false; 2451 } 2452 2453 private boolean undefinedCheck(final RuntimeNode runtimeNode, final List<Expression> args) { 2454 final Request request = runtimeNode.getRequest(); 2455 2456 if (!Request.isUndefinedCheck(request)) { 2457 return false; 2458 } 2459 2460 final Expression lhs = args.get(0); 2461 final Expression rhs = args.get(1); 2462 2463 final Symbol lhsSymbol = lhs instanceof IdentNode ? ((IdentNode)lhs).getSymbol() : null; 2464 final Symbol rhsSymbol = rhs instanceof IdentNode ? ((IdentNode)rhs).getSymbol() : null; 2465 // One must be a "undefined" identifier, otherwise we can't get here 2466 assert lhsSymbol != null || rhsSymbol != null; 2467 2468 final Symbol undefinedSymbol; 2469 if (isUndefinedSymbol(lhsSymbol)) { 2470 undefinedSymbol = lhsSymbol; 2471 } else { 2472 assert isUndefinedSymbol(rhsSymbol); 2473 undefinedSymbol = rhsSymbol; 2474 } 2475 2476 assert undefinedSymbol != null; //remove warning 2477 if (!undefinedSymbol.isScope()) { 2478 return false; //disallow undefined as local var or parameter 2479 } 2480 2481 if (lhsSymbol == undefinedSymbol && lhs.getType().isPrimitive()) { 2482 //we load the undefined first. never mind, because this will deoptimize anyway 2483 return false; 2484 } 2485 2486 if(isDeoptimizedExpression(lhs)) { 2487 // This is actually related to "lhs.getType().isPrimitive()" above: any expression being deoptimized in 2488 // the current chain of rest-of compilations used to have a type narrower than Object (so it was primitive). 2489 // We must not perform undefined check specialization for them, as then we'd violate the basic rule of 2490 // "Thou shalt not alter the stack shape between a deoptimized method and any of its (transitive) rest-ofs." 2491 return false; 2492 } 2493 2494 //make sure that undefined has not been overridden or scoped as a local var 2495 //between us and global 2496 if (!compiler.isGlobalSymbol(lc.getCurrentFunction(), "undefined")) { 2497 return false; 2498 } 2499 2500 final boolean isUndefinedCheck = request == Request.IS_UNDEFINED; 2501 final Expression expr = undefinedSymbol == lhsSymbol ? rhs : lhs; 2502 if (expr.getType().isPrimitive()) { 2503 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 2504 method.load(!isUndefinedCheck); 2505 } else { 2506 final Label checkTrue = new Label("ud_check_true"); 2507 final Label end = new Label("end"); 2508 loadExpressionAsObject(expr); 2509 method.loadUndefined(Type.OBJECT); 2510 method.if_acmpeq(checkTrue); 2511 method.load(!isUndefinedCheck); 2512 method._goto(end); 2513 method.label(checkTrue); 2514 method.load(isUndefinedCheck); 2515 method.label(end); 2516 } 2517 2518 return true; 2519 } 2520 2521 private static boolean isUndefinedSymbol(final Symbol symbol) { 2522 return symbol != null && "undefined".equals(symbol.getName()); 2523 } 2524 2525 private static boolean isNullLiteral(final Node node) { 2526 return node instanceof LiteralNode<?> && ((LiteralNode<?>) node).isNull(); 2527 } 2528 2529 private boolean nullCheck(final RuntimeNode runtimeNode, final List<Expression> args) { 2530 final Request request = runtimeNode.getRequest(); 2531 2532 if (!Request.isEQ(request) && !Request.isNE(request)) { 2533 return false; 2534 } 2535 2536 assert args.size() == 2 : "EQ or NE or TYPEOF need two args"; 2537 2538 Expression lhs = args.get(0); 2539 Expression rhs = args.get(1); 2540 2541 if (isNullLiteral(lhs)) { 2542 final Expression tmp = lhs; 2543 lhs = rhs; 2544 rhs = tmp; 2545 } 2546 2547 if (!isNullLiteral(rhs)) { 2548 return false; 2549 } 2550 2551 if (!lhs.getType().isObject()) { 2552 return false; 2553 } 2554 2555 if(isDeoptimizedExpression(lhs)) { 2556 // This is actually related to "!lhs.getType().isObject()" above: any expression being deoptimized in 2557 // the current chain of rest-of compilations used to have a type narrower than Object. We must not 2558 // perform null check specialization for them, as then we'd no longer be loading aconst_null on stack 2559 // and thus violate the basic rule of "Thou shalt not alter the stack shape between a deoptimized 2560 // method and any of its (transitive) rest-ofs." 2561 // NOTE also that if we had a representation for well-known constants (e.g. null, 0, 1, -1, etc.) in 2562 // Label$Stack.localLoads then this wouldn't be an issue, as we would never (somewhat ridiculously) 2563 // allocate a temporary local to hold the result of aconst_null before attempting an optimistic 2564 // operation. 2565 return false; 2566 } 2567 2568 // this is a null literal check, so if there is implicit coercion 2569 // involved like {D}x=null, we will fail - this is very rare 2570 final Label trueLabel = new Label("trueLabel"); 2571 final Label falseLabel = new Label("falseLabel"); 2572 final Label endLabel = new Label("end"); 2573 2574 loadExpressionUnbounded(lhs); //lhs 2575 final Label popLabel; 2576 if (!Request.isStrict(request)) { 2577 method.dup(); //lhs lhs 2578 popLabel = new Label("pop"); 2579 } else { 2580 popLabel = null; 2581 } 2582 2583 if (Request.isEQ(request)) { 2584 method.ifnull(!Request.isStrict(request) ? popLabel : trueLabel); 2585 if (!Request.isStrict(request)) { 2586 method.loadUndefined(Type.OBJECT); 2587 method.if_acmpeq(trueLabel); 2588 } 2589 method.label(falseLabel); 2590 method.load(false); 2591 method._goto(endLabel); 2592 if (!Request.isStrict(request)) { 2593 method.label(popLabel); 2594 method.pop(); 2595 } 2596 method.label(trueLabel); 2597 method.load(true); 2598 method.label(endLabel); 2599 } else if (Request.isNE(request)) { 2600 method.ifnull(!Request.isStrict(request) ? popLabel : falseLabel); 2601 if (!Request.isStrict(request)) { 2602 method.loadUndefined(Type.OBJECT); 2603 method.if_acmpeq(falseLabel); 2604 } 2605 method.label(trueLabel); 2606 method.load(true); 2607 method._goto(endLabel); 2608 if (!Request.isStrict(request)) { 2609 method.label(popLabel); 2610 method.pop(); 2611 } 2612 method.label(falseLabel); 2613 method.load(false); 2614 method.label(endLabel); 2615 } 2616 2617 assert runtimeNode.getType().isBoolean(); 2618 method.convert(runtimeNode.getType()); 2619 2620 return true; 2621 } 2622 2623 /** 2624 * Was this expression or any of its subexpressions deoptimized in the current recompilation chain of rest-of methods? 2625 * @param rootExpr the expression being tested 2626 * @return true if the expression or any of its subexpressions was deoptimized in the current recompilation chain. 2627 */ 2628 private boolean isDeoptimizedExpression(final Expression rootExpr) { 2629 if(!isRestOf()) { 2630 return false; 2631 } 2632 return new Supplier<Boolean>() { 2633 boolean contains; 2634 @Override 2635 public Boolean get() { 2636 rootExpr.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 2637 @Override 2638 public boolean enterFunctionNode(final FunctionNode functionNode) { 2639 return false; 2640 } 2641 @Override 2642 public boolean enterDefault(final Node node) { 2643 if(!contains && node instanceof Optimistic) { 2644 final int pp = ((Optimistic)node).getProgramPoint(); 2645 contains = isValid(pp) && isContinuationEntryPoint(pp); 2646 } 2647 return !contains; 2648 } 2649 }); 2650 return contains; 2651 } 2652 }.get(); 2653 } 2654 2655 private void loadRuntimeNode(final RuntimeNode runtimeNode) { 2656 final List<Expression> args = new ArrayList<>(runtimeNode.getArgs()); 2657 if (nullCheck(runtimeNode, args)) { 2658 return; 2659 } else if(undefinedCheck(runtimeNode, args)) { 2660 return; 2661 } 2662 // Revert a false undefined check to a strict equality check 2663 final RuntimeNode newRuntimeNode; 2664 final Request request = runtimeNode.getRequest(); 2665 if (Request.isUndefinedCheck(request)) { 2666 newRuntimeNode = runtimeNode.setRequest(request == Request.IS_UNDEFINED ? Request.EQ_STRICT : Request.NE_STRICT); 2667 } else { 2668 newRuntimeNode = runtimeNode; 2669 } 2670 2671 new OptimisticOperation(newRuntimeNode, TypeBounds.UNBOUNDED) { 2672 @Override 2673 void loadStack() { 2674 for (final Expression arg : args) { 2675 loadExpression(arg, TypeBounds.OBJECT); 2676 } 2677 } 2678 @Override 2679 void consumeStack() { 2680 method.invokestatic( 2681 CompilerConstants.className(ScriptRuntime.class), 2682 newRuntimeNode.getRequest().toString(), 2683 new FunctionSignature( 2684 false, 2685 false, 2686 newRuntimeNode.getType(), 2687 args.size()).toString()); 2688 } 2689 }.emit(); 2690 2691 method.convert(newRuntimeNode.getType()); 2692 } 2693 2694 @Override 2695 public boolean enterSplitNode(final SplitNode splitNode) { 2696 if(!method.isReachable()) { 2697 return false; 2698 } 2699 2700 final CompileUnit splitCompileUnit = splitNode.getCompileUnit(); 2701 2702 final FunctionNode fn = lc.getCurrentFunction(); 2703 final String className = splitCompileUnit.getUnitClassName(); 2704 final String name = splitNode.getName(); 2705 2706 final Type returnType = fn.getReturnType(); 2707 2708 final Class<?> rtype = fn.getReturnType().getTypeClass(); 2709 final boolean needsArguments = fn.needsArguments(); 2710 final Class<?>[] ptypes = needsArguments ? 2711 new Class<?>[] {ScriptFunction.class, Object.class, ScriptObject.class, ScriptObject.class} : 2712 new Class<?>[] {ScriptFunction.class, Object.class, ScriptObject.class}; 2713 2714 final MethodEmitter caller = method; 2715 unit = lc.pushCompileUnit(splitCompileUnit); 2716 2717 final Call splitCall = staticCallNoLookup( 2718 className, 2719 name, 2720 methodDescriptor(rtype, ptypes)); 2721 2722 final MethodEmitter splitEmitter = 2723 splitCompileUnit.getClassEmitter().method( 2724 splitNode, 2725 name, 2726 rtype, 2727 ptypes); 2728 2729 pushMethodEmitter(splitEmitter); 2730 method.setFunctionNode(fn); 2731 2732 assert fn.needsCallee() : "split function should require callee"; 2733 caller.loadCompilerConstant(CALLEE); 2734 caller.loadCompilerConstant(THIS); 2735 caller.loadCompilerConstant(SCOPE); 2736 if (needsArguments) { 2737 caller.loadCompilerConstant(ARGUMENTS); 2738 } 2739 caller.invoke(splitCall); 2740 caller.storeCompilerConstant(RETURN, returnType); 2741 2742 method.begin(); 2743 2744 defineCommonSplitMethodParameters(); 2745 if(needsArguments) { 2746 defineSplitMethodParameter(3, ARGUMENTS); 2747 } 2748 2749 // Copy scope to its target slot as first thing because the original slot could be used by return symbol. 2750 fixScopeSlot(fn); 2751 2752 final int returnSlot = fn.compilerConstant(RETURN).getSlot(returnType); 2753 method.defineBlockLocalVariable(returnSlot, returnSlot + returnType.getSlots()); 2754 method.loadUndefined(returnType); 2755 method.storeCompilerConstant(RETURN, returnType); 2756 2757 lc.enterSplitNode(); 2758 return true; 2759 } 2760 2761 private void defineCommonSplitMethodParameters() { 2762 defineSplitMethodParameter(0, CALLEE); 2763 defineSplitMethodParameter(1, THIS); 2764 defineSplitMethodParameter(2, SCOPE); 2765 } 2766 2767 private void defineSplitMethodParameter(final int slot, final CompilerConstants cc) { 2768 defineSplitMethodParameter(slot, Type.typeFor(cc.type())); 2769 } 2770 2771 private void defineSplitMethodParameter(final int slot, final Type type) { 2772 method.defineBlockLocalVariable(slot, slot + type.getSlots()); 2773 method.onLocalStore(type, slot); 2774 } 2775 2776 private void fixScopeSlot(final FunctionNode functionNode) { 2777 // TODO hack to move the scope to the expected slot (needed because split methods reuse the same slots as the root method) 2778 final int actualScopeSlot = functionNode.compilerConstant(SCOPE).getSlot(SCOPE_TYPE); 2779 final int defaultScopeSlot = SCOPE.slot(); 2780 if (actualScopeSlot != defaultScopeSlot) { 2781 method.defineBlockLocalVariable(actualScopeSlot, actualScopeSlot + 1); 2782 method.load(SCOPE_TYPE, defaultScopeSlot); 2783 method.storeCompilerConstant(SCOPE); 2784 } 2785 } 2786 2787 @Override 2788 public Node leaveSplitNode(final SplitNode splitNode) { 2789 assert method instanceof SplitMethodEmitter; 2790 lc.exitSplitNode(); 2791 final boolean hasReturn = method.hasReturn(); 2792 final SplitMethodEmitter splitMethod = ((SplitMethodEmitter)method); 2793 final List<Label> targets = splitMethod.getExternalTargets(); 2794 final List<BreakableNode> targetNodes = splitMethod.getExternalTargetNodes(); 2795 final Type returnType = lc.getCurrentFunction().getReturnType(); 2796 2797 try { 2798 // Wrap up this method. 2799 2800 if(method.isReachable()) { 2801 method.loadCompilerConstant(RETURN, returnType); 2802 method._return(returnType); 2803 } 2804 method.end(); 2805 2806 lc.releaseSlots(); 2807 2808 unit = lc.popCompileUnit(splitNode.getCompileUnit()); 2809 popMethodEmitter(); 2810 2811 } catch (final Throwable t) { 2812 Context.printStackTrace(t); 2813 final VerifyError e = new VerifyError("Code generation bug in \"" + splitNode.getName() + "\": likely stack misaligned: " + t + " " + getCurrentSource().getName()); 2814 e.initCause(t); 2815 throw e; 2816 } 2817 2818 // Handle return from split method if there was one. 2819 final MethodEmitter caller = method; 2820 final int targetCount = targets.size(); 2821 2822 //no external jump targets or return in switch node 2823 if (!hasReturn && targets.isEmpty()) { 2824 return splitNode; 2825 } 2826 2827 caller.loadCompilerConstant(SCOPE); 2828 caller.checkcast(Scope.class); 2829 caller.invoke(Scope.GET_SPLIT_STATE); 2830 2831 final Label breakLabel = new Label("no_split_state"); 2832 // Split state is -1 for no split state, 0 for return, 1..n+1 for break/continue 2833 2834 //the common case is that we don't need a switch 2835 if (targetCount == 0) { 2836 assert hasReturn; 2837 caller.ifne(breakLabel); 2838 //has to be zero 2839 caller.label(new Label("split_return")); 2840 caller.loadCompilerConstant(RETURN, returnType); 2841 caller._return(returnType); 2842 caller.label(breakLabel); 2843 } else { 2844 assert !targets.isEmpty(); 2845 2846 final int low = hasReturn ? 0 : 1; 2847 final int labelCount = targetCount + 1 - low; 2848 final Label[] labels = new Label[labelCount]; 2849 2850 for (int i = 0; i < labelCount; i++) { 2851 labels[i] = new Label(i == 0 ? "split_return" : "split_" + targets.get(i - 1)); 2852 } 2853 caller.tableswitch(low, targetCount, breakLabel, labels); 2854 for (int i = low; i <= targetCount; i++) { 2855 caller.label(labels[i - low]); 2856 if (i == 0) { 2857 caller.loadCompilerConstant(RETURN, returnType); 2858 caller._return(returnType); 2859 } else { 2860 // Clear split state. 2861 caller.loadCompilerConstant(SCOPE); 2862 caller.checkcast(Scope.class); 2863 caller.load(-1); 2864 caller.invoke(Scope.SET_SPLIT_STATE); 2865 final BreakableNode targetNode = targetNodes.get(i - 1); 2866 final Label label = targets.get(i - 1); 2867 final JoinPredecessor jumpOrigin = splitNode.getJumpOrigin(label); 2868 if(jumpOrigin != null) { 2869 method.beforeJoinPoint(jumpOrigin); 2870 } 2871 popScopesUntil(targetNode); 2872 caller.splitAwareGoto(lc, targets.get(i - 1), targetNode); 2873 } 2874 } 2875 caller.label(breakLabel); 2876 } 2877 2878 // If split has a return and caller is itself a split method it needs to propagate the return. 2879 if (hasReturn) { 2880 caller.setHasReturn(); 2881 } 2882 2883 return splitNode; 2884 } 2885 2886 @Override 2887 public boolean enterSwitchNode(final SwitchNode switchNode) { 2888 if(!method.isReachable()) { 2889 return false; 2890 } 2891 enterStatement(switchNode); 2892 2893 final Expression expression = switchNode.getExpression(); 2894 final List<CaseNode> cases = switchNode.getCases(); 2895 2896 if (cases.isEmpty()) { 2897 // still evaluate expression for side-effects. 2898 loadAndDiscard(expression); 2899 return false; 2900 } 2901 2902 final CaseNode defaultCase = switchNode.getDefaultCase(); 2903 final Label breakLabel = switchNode.getBreakLabel(); 2904 final int liveLocalsOnBreak = method.getUsedSlotsWithLiveTemporaries(); 2905 2906 if (defaultCase != null && cases.size() == 1) { 2907 // default case only 2908 assert cases.get(0) == defaultCase; 2909 loadAndDiscard(expression); 2910 defaultCase.getBody().accept(this); 2911 method.breakLabel(breakLabel, liveLocalsOnBreak); 2912 return false; 2913 } 2914 2915 // NOTE: it can still change in the tableswitch/lookupswitch case if there's no default case 2916 // but we need to add a synthetic default case for local variable conversions 2917 Label defaultLabel = defaultCase != null ? defaultCase.getEntry() : breakLabel; 2918 final boolean hasSkipConversion = LocalVariableConversion.hasLiveConversion(switchNode); 2919 2920 if (switchNode.isInteger()) { 2921 // Tree for sorting values. 2922 final TreeMap<Integer, Label> tree = new TreeMap<>(); 2923 2924 // Build up sorted tree. 2925 for (final CaseNode caseNode : cases) { 2926 final Node test = caseNode.getTest(); 2927 2928 if (test != null) { 2929 final Integer value = (Integer)((LiteralNode<?>)test).getValue(); 2930 final Label entry = caseNode.getEntry(); 2931 2932 // Take first duplicate. 2933 if (!tree.containsKey(value)) { 2934 tree.put(value, entry); 2935 } 2936 } 2937 } 2938 2939 // Copy values and labels to arrays. 2940 final int size = tree.size(); 2941 final Integer[] values = tree.keySet().toArray(new Integer[size]); 2942 final Label[] labels = tree.values().toArray(new Label[size]); 2943 2944 // Discern low, high and range. 2945 final int lo = values[0]; 2946 final int hi = values[size - 1]; 2947 final long range = (long)hi - (long)lo + 1; 2948 2949 // Find an unused value for default. 2950 int deflt = Integer.MIN_VALUE; 2951 for (final int value : values) { 2952 if (deflt == value) { 2953 deflt++; 2954 } else if (deflt < value) { 2955 break; 2956 } 2957 } 2958 2959 // Load switch expression. 2960 loadExpressionUnbounded(expression); 2961 final Type type = expression.getType(); 2962 2963 // If expression not int see if we can convert, if not use deflt to trigger default. 2964 if (!type.isInteger()) { 2965 method.load(deflt); 2966 final Class<?> exprClass = type.getTypeClass(); 2967 method.invoke(staticCallNoLookup(ScriptRuntime.class, "switchTagAsInt", int.class, exprClass.isPrimitive()? exprClass : Object.class, int.class)); 2968 } 2969 2970 if(hasSkipConversion) { 2971 assert defaultLabel == breakLabel; 2972 defaultLabel = new Label("switch_skip"); 2973 } 2974 // TABLESWITCH needs (range + 3) 32-bit values; LOOKUPSWITCH needs ((size * 2) + 2). Choose the one with 2975 // smaller representation, favor TABLESWITCH when they're equal size. 2976 if (range + 1 <= (size * 2) && range <= Integer.MAX_VALUE) { 2977 final Label[] table = new Label[(int)range]; 2978 Arrays.fill(table, defaultLabel); 2979 for (int i = 0; i < size; i++) { 2980 final int value = values[i]; 2981 table[value - lo] = labels[i]; 2982 } 2983 2984 method.tableswitch(lo, hi, defaultLabel, table); 2985 } else { 2986 final int[] ints = new int[size]; 2987 for (int i = 0; i < size; i++) { 2988 ints[i] = values[i]; 2989 } 2990 2991 method.lookupswitch(defaultLabel, ints, labels); 2992 } 2993 // This is a synthetic "default case" used in absence of actual default case, created if we need to apply 2994 // local variable conversions if neither case is taken. 2995 if(hasSkipConversion) { 2996 method.label(defaultLabel); 2997 method.beforeJoinPoint(switchNode); 2998 method._goto(breakLabel); 2999 } 3000 } else { 3001 final Symbol tagSymbol = switchNode.getTag(); 3002 // TODO: we could have non-object tag 3003 final int tagSlot = tagSymbol.getSlot(Type.OBJECT); 3004 loadExpressionAsObject(expression); 3005 method.store(tagSymbol, Type.OBJECT); 3006 3007 for (final CaseNode caseNode : cases) { 3008 final Expression test = caseNode.getTest(); 3009 3010 if (test != null) { 3011 method.load(Type.OBJECT, tagSlot); 3012 loadExpressionAsObject(test); 3013 method.invoke(ScriptRuntime.EQ_STRICT); 3014 method.ifne(caseNode.getEntry()); 3015 } 3016 } 3017 3018 if (defaultCase != null) { 3019 method._goto(defaultLabel); 3020 } else { 3021 method.beforeJoinPoint(switchNode); 3022 method._goto(breakLabel); 3023 } 3024 } 3025 3026 // First case is only reachable through jump 3027 assert !method.isReachable(); 3028 3029 for (final CaseNode caseNode : cases) { 3030 final Label fallThroughLabel; 3031 if(caseNode.getLocalVariableConversion() != null && method.isReachable()) { 3032 fallThroughLabel = new Label("fallthrough"); 3033 method._goto(fallThroughLabel); 3034 } else { 3035 fallThroughLabel = null; 3036 } 3037 method.label(caseNode.getEntry()); 3038 method.beforeJoinPoint(caseNode); 3039 if(fallThroughLabel != null) { 3040 method.label(fallThroughLabel); 3041 } 3042 caseNode.getBody().accept(this); 3043 } 3044 3045 method.breakLabel(breakLabel, liveLocalsOnBreak); 3046 3047 return false; 3048 } 3049 3050 @Override 3051 public boolean enterThrowNode(final ThrowNode throwNode) { 3052 if(!method.isReachable()) { 3053 return false; 3054 } 3055 enterStatement(throwNode); 3056 3057 if (throwNode.isSyntheticRethrow()) { 3058 method.beforeJoinPoint(throwNode); 3059 3060 //do not wrap whatever this is in an ecma exception, just rethrow it 3061 final IdentNode exceptionExpr = (IdentNode)throwNode.getExpression(); 3062 final Symbol exceptionSymbol = exceptionExpr.getSymbol(); 3063 method.load(exceptionSymbol, EXCEPTION_TYPE); 3064 method.checkcast(EXCEPTION_TYPE.getTypeClass()); 3065 method.athrow(); 3066 return false; 3067 } 3068 3069 final Source source = getCurrentSource(); 3070 final Expression expression = throwNode.getExpression(); 3071 final int position = throwNode.position(); 3072 final int line = throwNode.getLineNumber(); 3073 final int column = source.getColumn(position); 3074 3075 // NOTE: we first evaluate the expression, and only after it was evaluated do we create the new ECMAException 3076 // object and then somewhat cumbersomely move it beneath the evaluated expression on the stack. The reason for 3077 // this is that if expression is optimistic (or contains an optimistic subexpression), we'd potentially access 3078 // the not-yet-<init>ialized object on the stack from the UnwarrantedOptimismException handler, and bytecode 3079 // verifier forbids that. 3080 loadExpressionAsObject(expression); 3081 3082 method.load(source.getName()); 3083 method.load(line); 3084 method.load(column); 3085 method.invoke(ECMAException.CREATE); 3086 3087 method.beforeJoinPoint(throwNode); 3088 method.athrow(); 3089 3090 return false; 3091 } 3092 3093 private Source getCurrentSource() { 3094 return lc.getCurrentFunction().getSource(); 3095 } 3096 3097 @Override 3098 public boolean enterTryNode(final TryNode tryNode) { 3099 if(!method.isReachable()) { 3100 return false; 3101 } 3102 enterStatement(tryNode); 3103 3104 final Block body = tryNode.getBody(); 3105 final List<Block> catchBlocks = tryNode.getCatchBlocks(); 3106 final Symbol vmException = tryNode.getException(); 3107 final Label entry = new Label("try"); 3108 final Label recovery = new Label("catch"); 3109 final Label exit = new Label("end_try"); 3110 final Label skip = new Label("skip"); 3111 3112 method.canThrow(recovery); 3113 // Effect any conversions that might be observed at the entry of the catch node before entering the try node. 3114 // This is because even the first instruction in the try block must be presumed to be able to transfer control 3115 // to the catch block. Note that this doesn't kill the original values; in this regard it works a lot like 3116 // conversions of assignments within the try block. 3117 method.beforeTry(tryNode, recovery); 3118 method.label(entry); 3119 catchLabels.push(recovery); 3120 try { 3121 body.accept(this); 3122 } finally { 3123 assert catchLabels.peek() == recovery; 3124 catchLabels.pop(); 3125 } 3126 3127 method.label(exit); 3128 final boolean bodyCanThrow = exit.isAfter(entry); 3129 if(!bodyCanThrow) { 3130 // The body can't throw an exception; don't even bother emitting the catch handlers, they're all dead code. 3131 return false; 3132 } 3133 3134 method._try(entry, exit, recovery, Throwable.class); 3135 3136 if (method.isReachable()) { 3137 method._goto(skip); 3138 } 3139 method._catch(recovery); 3140 method.store(vmException, EXCEPTION_TYPE); 3141 3142 final int catchBlockCount = catchBlocks.size(); 3143 final Label afterCatch = new Label("after_catch"); 3144 for (int i = 0; i < catchBlockCount; i++) { 3145 assert method.isReachable(); 3146 final Block catchBlock = catchBlocks.get(i); 3147 3148 // Because of the peculiarities of the flow control, we need to use an explicit push/enterBlock/leaveBlock 3149 // here. 3150 lc.push(catchBlock); 3151 enterBlock(catchBlock); 3152 3153 final CatchNode catchNode = (CatchNode)catchBlocks.get(i).getStatements().get(0); 3154 final IdentNode exception = catchNode.getException(); 3155 final Expression exceptionCondition = catchNode.getExceptionCondition(); 3156 final Block catchBody = catchNode.getBody(); 3157 3158 new Store<IdentNode>(exception) { 3159 @Override 3160 protected void storeNonDiscard() { 3161 // This expression is neither part of a discard, nor needs to be left on the stack after it was 3162 // stored, so we override storeNonDiscard to be a no-op. 3163 } 3164 3165 @Override 3166 protected void evaluate() { 3167 if (catchNode.isSyntheticRethrow()) { 3168 method.load(vmException, EXCEPTION_TYPE); 3169 return; 3170 } 3171 /* 3172 * If caught object is an instance of ECMAException, then 3173 * bind obj.thrown to the script catch var. Or else bind the 3174 * caught object itself to the script catch var. 3175 */ 3176 final Label notEcmaException = new Label("no_ecma_exception"); 3177 method.load(vmException, EXCEPTION_TYPE).dup()._instanceof(ECMAException.class).ifeq(notEcmaException); 3178 method.checkcast(ECMAException.class); //TODO is this necessary? 3179 method.getField(ECMAException.THROWN); 3180 method.label(notEcmaException); 3181 } 3182 }.store(); 3183 3184 final boolean isConditionalCatch = exceptionCondition != null; 3185 final Label nextCatch; 3186 if (isConditionalCatch) { 3187 loadExpressionAsBoolean(exceptionCondition); 3188 nextCatch = new Label("next_catch"); 3189 method.ifeq(nextCatch); 3190 } else { 3191 nextCatch = null; 3192 } 3193 3194 catchBody.accept(this); 3195 leaveBlock(catchBlock); 3196 lc.pop(catchBlock); 3197 if(method.isReachable()) { 3198 method._goto(afterCatch); 3199 } 3200 if(nextCatch != null) { 3201 method.label(nextCatch); 3202 } 3203 } 3204 3205 assert !method.isReachable(); 3206 // afterCatch could be the same as skip, except that we need to establish that the vmException is dead. 3207 method.label(afterCatch); 3208 if(method.isReachable()) { 3209 method.markDeadLocalVariable(vmException); 3210 } 3211 method.label(skip); 3212 3213 // Finally body is always inlined elsewhere so it doesn't need to be emitted 3214 return false; 3215 } 3216 3217 @Override 3218 public boolean enterVarNode(final VarNode varNode) { 3219 if(!method.isReachable()) { 3220 return false; 3221 } 3222 final Expression init = varNode.getInit(); 3223 3224 if (init == null) { 3225 return false; 3226 } 3227 3228 enterStatement(varNode); 3229 3230 final IdentNode identNode = varNode.getName(); 3231 final Symbol identSymbol = identNode.getSymbol(); 3232 assert identSymbol != null : "variable node " + varNode + " requires a name with a symbol"; 3233 3234 assert method != null; 3235 3236 final boolean needsScope = identSymbol.isScope(); 3237 if (needsScope) { 3238 method.loadCompilerConstant(SCOPE); 3239 } 3240 3241 if (needsScope) { 3242 loadExpressionUnbounded(init); 3243 final int flags = CALLSITE_SCOPE | getCallSiteFlags(); 3244 if (isFastScope(identSymbol)) { 3245 storeFastScopeVar(identSymbol, flags); 3246 } else { 3247 method.dynamicSet(identNode.getName(), flags); 3248 } 3249 } else { 3250 final Type identType = identNode.getType(); 3251 if(identType == Type.UNDEFINED) { 3252 // The symbol must not be slotted; the initializer is either itself undefined (explicit assignment of 3253 // undefined to undefined), or the left hand side is a dead variable. 3254 assert !identNode.getSymbol().isScope(); 3255 assert init.getType() == Type.UNDEFINED || identNode.getSymbol().slotCount() == 0; 3256 loadAndDiscard(init); 3257 return false; 3258 } 3259 loadExpressionAsType(init, identType); 3260 storeIdentWithCatchConversion(identNode, identType); 3261 } 3262 3263 return false; 3264 } 3265 3266 private void storeIdentWithCatchConversion(final IdentNode identNode, final Type type) { 3267 // Assignments happening in try/catch blocks need to ensure that they also store a possibly wider typed value 3268 // that will be live at the exit from the try block 3269 final LocalVariableConversion conversion = identNode.getLocalVariableConversion(); 3270 final Symbol symbol = identNode.getSymbol(); 3271 if(conversion != null && conversion.isLive()) { 3272 assert symbol == conversion.getSymbol(); 3273 assert symbol.isBytecodeLocal(); 3274 // Only a single conversion from the target type to the join type is expected. 3275 assert conversion.getNext() == null; 3276 assert conversion.getFrom() == type; 3277 // We must propagate potential type change to the catch block 3278 final Label catchLabel = catchLabels.peek(); 3279 assert catchLabel != METHOD_BOUNDARY; // ident conversion only exists in try blocks 3280 assert catchLabel.isReachable(); 3281 final Type joinType = conversion.getTo(); 3282 final Label.Stack catchStack = catchLabel.getStack(); 3283 final int joinSlot = symbol.getSlot(joinType); 3284 // With nested try/catch blocks (incl. synthetic ones for finally), we can have a supposed conversion for 3285 // the exception symbol in the nested catch, but it isn't live in the outer catch block, so prevent doing 3286 // conversions for it. E.g. in "try { try { ... } catch(e) { e = 1; } } catch(e2) { ... }", we must not 3287 // introduce an I->O conversion on "e = 1" assignment as "e" is not live in "catch(e2)". 3288 if(catchStack.getUsedSlotsWithLiveTemporaries() > joinSlot) { 3289 method.dup(); 3290 method.convert(joinType); 3291 method.store(symbol, joinType); 3292 catchLabel.getStack().onLocalStore(joinType, joinSlot, true); 3293 method.canThrow(catchLabel); 3294 // Store but keep the previous store live too. 3295 method.store(symbol, type, false); 3296 return; 3297 } 3298 } 3299 3300 method.store(symbol, type, true); 3301 } 3302 3303 @Override 3304 public boolean enterWhileNode(final WhileNode whileNode) { 3305 if(!method.isReachable()) { 3306 return false; 3307 } 3308 if(whileNode.isDoWhile()) { 3309 enterDoWhile(whileNode); 3310 } else { 3311 enterStatement(whileNode); 3312 enterForOrWhile(whileNode, null); 3313 } 3314 return false; 3315 } 3316 3317 private void enterForOrWhile(final LoopNode loopNode, final JoinPredecessorExpression modify) { 3318 // NOTE: the usual pattern for compiling test-first loops is "GOTO test; body; test; IFNE body". We use the less 3319 // conventional "test; IFEQ break; body; GOTO test; break;". It has one extra unconditional GOTO in each repeat 3320 // of the loop, but it's not a problem for modern JIT compilers. We do this because our local variable type 3321 // tracking is unfortunately not really prepared for out-of-order execution, e.g. compiling the following 3322 // contrived but legal JavaScript code snippet would fail because the test changes the type of "i" from object 3323 // to double: var i = {valueOf: function() { return 1} }; while(--i >= 0) { ... } 3324 // Instead of adding more complexity to the local variable type tracking, we instead choose to emit this 3325 // different code shape. 3326 final int liveLocalsOnBreak = method.getUsedSlotsWithLiveTemporaries(); 3327 final JoinPredecessorExpression test = loopNode.getTest(); 3328 if(Expression.isAlwaysFalse(test)) { 3329 loadAndDiscard(test); 3330 return; 3331 } 3332 3333 method.beforeJoinPoint(loopNode); 3334 3335 final Label continueLabel = loopNode.getContinueLabel(); 3336 final Label repeatLabel = modify != null ? new Label("for_repeat") : continueLabel; 3337 method.label(repeatLabel); 3338 final int liveLocalsOnContinue = method.getUsedSlotsWithLiveTemporaries(); 3339 3340 final Block body = loopNode.getBody(); 3341 final Label breakLabel = loopNode.getBreakLabel(); 3342 final boolean testHasLiveConversion = test != null && LocalVariableConversion.hasLiveConversion(test); 3343 3344 if(Expression.isAlwaysTrue(test)) { 3345 if(test != null) { 3346 loadAndDiscard(test); 3347 if(testHasLiveConversion) { 3348 method.beforeJoinPoint(test); 3349 } 3350 } 3351 } else if (test != null) { 3352 if (testHasLiveConversion) { 3353 emitBranch(test.getExpression(), body.getEntryLabel(), true); 3354 method.beforeJoinPoint(test); 3355 method._goto(breakLabel); 3356 } else { 3357 emitBranch(test.getExpression(), breakLabel, false); 3358 } 3359 } 3360 3361 body.accept(this); 3362 if(repeatLabel != continueLabel) { 3363 emitContinueLabel(continueLabel, liveLocalsOnContinue); 3364 } 3365 3366 if(method.isReachable()) { 3367 if(modify != null) { 3368 lineNumber(loopNode); 3369 loadAndDiscard(modify); 3370 method.beforeJoinPoint(modify); 3371 } 3372 method._goto(repeatLabel); 3373 } 3374 3375 method.breakLabel(breakLabel, liveLocalsOnBreak); 3376 } 3377 3378 private void emitContinueLabel(final Label continueLabel, final int liveLocals) { 3379 final boolean reachable = method.isReachable(); 3380 method.breakLabel(continueLabel, liveLocals); 3381 // If we reach here only through a continue statement (e.g. body does not exit normally) then the 3382 // continueLabel can have extra non-temp symbols (e.g. exception from a try/catch contained in the body). We 3383 // must make sure those are thrown away. 3384 if(!reachable) { 3385 method.undefineLocalVariables(lc.getUsedSlotCount(), false); 3386 } 3387 } 3388 3389 private void enterDoWhile(final WhileNode whileNode) { 3390 final int liveLocalsOnContinueOrBreak = method.getUsedSlotsWithLiveTemporaries(); 3391 method.beforeJoinPoint(whileNode); 3392 3393 final Block body = whileNode.getBody(); 3394 body.accept(this); 3395 3396 emitContinueLabel(whileNode.getContinueLabel(), liveLocalsOnContinueOrBreak); 3397 if(method.isReachable()) { 3398 lineNumber(whileNode); 3399 final JoinPredecessorExpression test = whileNode.getTest(); 3400 final Label bodyEntryLabel = body.getEntryLabel(); 3401 final boolean testHasLiveConversion = LocalVariableConversion.hasLiveConversion(test); 3402 if(Expression.isAlwaysFalse(test)) { 3403 loadAndDiscard(test); 3404 if(testHasLiveConversion) { 3405 method.beforeJoinPoint(test); 3406 } 3407 } else if(testHasLiveConversion) { 3408 // If we have conversions after the test in do-while, they need to be effected on both branches. 3409 final Label beforeExit = new Label("do_while_preexit"); 3410 emitBranch(test.getExpression(), beforeExit, false); 3411 method.beforeJoinPoint(test); 3412 method._goto(bodyEntryLabel); 3413 method.label(beforeExit); 3414 method.beforeJoinPoint(test); 3415 } else { 3416 emitBranch(test.getExpression(), bodyEntryLabel, true); 3417 } 3418 } 3419 method.breakLabel(whileNode.getBreakLabel(), liveLocalsOnContinueOrBreak); 3420 } 3421 3422 3423 @Override 3424 public boolean enterWithNode(final WithNode withNode) { 3425 if(!method.isReachable()) { 3426 return false; 3427 } 3428 enterStatement(withNode); 3429 final Expression expression = withNode.getExpression(); 3430 final Block body = withNode.getBody(); 3431 3432 // It is possible to have a "pathological" case where the with block does not reference *any* identifiers. It's 3433 // pointless, but legal. In that case, if nothing else in the method forced the assignment of a slot to the 3434 // scope object, its' possible that it won't have a slot assigned. In this case we'll only evaluate expression 3435 // for its side effect and visit the body, and not bother opening and closing a WithObject. 3436 final boolean hasScope = method.hasScope(); 3437 3438 if (hasScope) { 3439 method.loadCompilerConstant(SCOPE); 3440 } 3441 3442 loadExpressionAsObject(expression); 3443 3444 final Label tryLabel; 3445 if (hasScope) { 3446 // Construct a WithObject if we have a scope 3447 method.invoke(ScriptRuntime.OPEN_WITH); 3448 method.storeCompilerConstant(SCOPE); 3449 tryLabel = new Label("with_try"); 3450 method.label(tryLabel); 3451 } else { 3452 // We just loaded the expression for its side effect and to check 3453 // for null or undefined value. 3454 globalCheckObjectCoercible(); 3455 tryLabel = null; 3456 } 3457 3458 // Always process body 3459 body.accept(this); 3460 3461 if (hasScope) { 3462 // Ensure we always close the WithObject 3463 final Label endLabel = new Label("with_end"); 3464 final Label catchLabel = new Label("with_catch"); 3465 final Label exitLabel = new Label("with_exit"); 3466 3467 method.label(endLabel); 3468 // Somewhat conservatively presume that if the body is not empty, it can throw an exception. In any case, 3469 // we must prevent trying to emit a try-catch for empty range, as it causes a verification error. 3470 final boolean bodyCanThrow = endLabel.isAfter(tryLabel); 3471 if(bodyCanThrow) { 3472 method._try(tryLabel, endLabel, catchLabel); 3473 } 3474 3475 final boolean reachable = method.isReachable(); 3476 if(reachable) { 3477 popScope(); 3478 if(bodyCanThrow) { 3479 method._goto(exitLabel); 3480 } 3481 } 3482 3483 if(bodyCanThrow) { 3484 method._catch(catchLabel); 3485 popScopeException(); 3486 method.athrow(); 3487 if(reachable) { 3488 method.label(exitLabel); 3489 } 3490 } 3491 } 3492 return false; 3493 } 3494 3495 private void loadADD(final UnaryNode unaryNode, final TypeBounds resultBounds) { 3496 loadExpression(unaryNode.getExpression(), resultBounds.booleanToInt().notWiderThan(Type.NUMBER)); 3497 if(method.peekType() == Type.BOOLEAN) { 3498 // It's a no-op in bytecode, but we must make sure it is treated as an int for purposes of type signatures 3499 method.convert(Type.INT); 3500 } 3501 } 3502 3503 private void loadBIT_NOT(final UnaryNode unaryNode) { 3504 loadExpression(unaryNode.getExpression(), TypeBounds.INT).load(-1).xor(); 3505 } 3506 3507 private void loadDECINC(final UnaryNode unaryNode) { 3508 final Expression operand = unaryNode.getExpression(); 3509 final Type type = unaryNode.getType(); 3510 final TypeBounds typeBounds = new TypeBounds(type, Type.NUMBER); 3511 final TokenType tokenType = unaryNode.tokenType(); 3512 final boolean isPostfix = tokenType == TokenType.DECPOSTFIX || tokenType == TokenType.INCPOSTFIX; 3513 final boolean isIncrement = tokenType == TokenType.INCPREFIX || tokenType == TokenType.INCPOSTFIX; 3514 3515 assert !type.isObject(); 3516 3517 new SelfModifyingStore<UnaryNode>(unaryNode, operand) { 3518 3519 private void loadRhs() { 3520 loadExpression(operand, typeBounds, true); 3521 } 3522 3523 @Override 3524 protected void evaluate() { 3525 if(isPostfix) { 3526 loadRhs(); 3527 } else { 3528 new OptimisticOperation(unaryNode, typeBounds) { 3529 @Override 3530 void loadStack() { 3531 loadRhs(); 3532 loadMinusOne(); 3533 } 3534 @Override 3535 void consumeStack() { 3536 doDecInc(getProgramPoint()); 3537 } 3538 }.emit(getOptimisticIgnoreCountForSelfModifyingExpression(operand)); 3539 } 3540 } 3541 3542 @Override 3543 protected void storeNonDiscard() { 3544 super.storeNonDiscard(); 3545 if (isPostfix) { 3546 new OptimisticOperation(unaryNode, typeBounds) { 3547 @Override 3548 void loadStack() { 3549 loadMinusOne(); 3550 } 3551 @Override 3552 void consumeStack() { 3553 doDecInc(getProgramPoint()); 3554 } 3555 }.emit(1); // 1 for non-incremented result on the top of the stack pushed in evaluate() 3556 } 3557 } 3558 3559 private void loadMinusOne() { 3560 if (type.isInteger()) { 3561 method.load(isIncrement ? 1 : -1); 3562 } else if (type.isLong()) { 3563 method.load(isIncrement ? 1L : -1L); 3564 } else { 3565 method.load(isIncrement ? 1.0 : -1.0); 3566 } 3567 } 3568 3569 private void doDecInc(final int programPoint) { 3570 method.add(programPoint); 3571 } 3572 }.store(); 3573 } 3574 3575 private static int getOptimisticIgnoreCountForSelfModifyingExpression(final Expression target) { 3576 return target instanceof AccessNode ? 1 : target instanceof IndexNode ? 2 : 0; 3577 } 3578 3579 private void loadAndDiscard(final Expression expr) { 3580 // TODO: move checks for discarding to actual expression load code (e.g. as we do with void). That way we might 3581 // be able to eliminate even more checks. 3582 if(expr instanceof PrimitiveLiteralNode | isLocalVariable(expr)) { 3583 assert lc.getCurrentDiscard() != expr; 3584 // Don't bother evaluating expressions without side effects. Typical usage is "void 0" for reliably generating 3585 // undefined. 3586 return; 3587 } 3588 3589 lc.pushDiscard(expr); 3590 loadExpression(expr, TypeBounds.UNBOUNDED); 3591 if (lc.getCurrentDiscard() == expr) { 3592 assert !expr.isAssignment(); 3593 // NOTE: if we had a way to load with type void, we could avoid popping 3594 method.pop(); 3595 lc.popDiscard(); 3596 } 3597 } 3598 3599 private void loadNEW(final UnaryNode unaryNode) { 3600 final CallNode callNode = (CallNode)unaryNode.getExpression(); 3601 final List<Expression> args = callNode.getArgs(); 3602 3603 // Load function reference. 3604 loadExpressionAsObject(callNode.getFunction()); // must detect type error 3605 3606 method.dynamicNew(1 + loadArgs(args), getCallSiteFlags()); 3607 } 3608 3609 private void loadNOT(final UnaryNode unaryNode) { 3610 final Expression expr = unaryNode.getExpression(); 3611 if(expr instanceof UnaryNode && expr.isTokenType(TokenType.NOT)) { 3612 // !!x is idiomatic boolean cast in JavaScript 3613 loadExpressionAsBoolean(((UnaryNode)expr).getExpression()); 3614 } else { 3615 final Label trueLabel = new Label("true"); 3616 final Label afterLabel = new Label("after"); 3617 3618 emitBranch(expr, trueLabel, true); 3619 method.load(true); 3620 method._goto(afterLabel); 3621 method.label(trueLabel); 3622 method.load(false); 3623 method.label(afterLabel); 3624 } 3625 } 3626 3627 private void loadSUB(final UnaryNode unaryNode, final TypeBounds resultBounds) { 3628 final Type type = unaryNode.getType(); 3629 assert type.isNumeric(); 3630 final TypeBounds numericBounds = resultBounds.booleanToInt(); 3631 new OptimisticOperation(unaryNode, numericBounds) { 3632 @Override 3633 void loadStack() { 3634 final Expression expr = unaryNode.getExpression(); 3635 loadExpression(expr, numericBounds.notWiderThan(Type.NUMBER)); 3636 } 3637 @Override 3638 void consumeStack() { 3639 // Must do an explicit conversion to the operation's type when it's double so that we correctly handle 3640 // negation of an int 0 to a double -0. With this, we get the correct negation of a local variable after 3641 // it deoptimized, e.g. "iload_2; i2d; dneg". Without this, we get "iload_2; ineg; i2d". 3642 if(type.isNumber()) { 3643 method.convert(type); 3644 } 3645 method.neg(getProgramPoint()); 3646 } 3647 }.emit(); 3648 } 3649 3650 public void loadVOID(final UnaryNode unaryNode, final TypeBounds resultBounds) { 3651 loadAndDiscard(unaryNode.getExpression()); 3652 if(lc.getCurrentDiscard() == unaryNode) { 3653 lc.popDiscard(); 3654 } else { 3655 method.loadUndefined(resultBounds.widest); 3656 } 3657 } 3658 3659 public void loadADD(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3660 new OptimisticOperation(binaryNode, resultBounds) { 3661 @Override 3662 void loadStack() { 3663 final TypeBounds operandBounds; 3664 final boolean isOptimistic = isValid(getProgramPoint()); 3665 if(isOptimistic) { 3666 operandBounds = new TypeBounds(binaryNode.getType(), Type.OBJECT); 3667 } else { 3668 // Non-optimistic, non-FP +. Allow it to overflow. 3669 operandBounds = new TypeBounds(binaryNode.getWidestOperandType(), Type.OBJECT); 3670 } 3671 loadBinaryOperands(binaryNode.lhs(), binaryNode.rhs(), operandBounds, false); 3672 } 3673 3674 @Override 3675 void consumeStack() { 3676 method.add(getProgramPoint()); 3677 } 3678 }.emit(); 3679 } 3680 3681 private void loadAND_OR(final BinaryNode binaryNode, final TypeBounds resultBounds, final boolean isAnd) { 3682 final Type narrowestOperandType = Type.widestReturnType(binaryNode.lhs().getType(), binaryNode.rhs().getType()); 3683 3684 final Label skip = new Label("skip"); 3685 if(narrowestOperandType == Type.BOOLEAN) { 3686 // optimize all-boolean logical expressions 3687 final Label onTrue = new Label("andor_true"); 3688 emitBranch(binaryNode, onTrue, true); 3689 method.load(false); 3690 method._goto(skip); 3691 method.label(onTrue); 3692 method.load(true); 3693 method.label(skip); 3694 return; 3695 } 3696 3697 final TypeBounds outBounds = resultBounds.notNarrowerThan(narrowestOperandType); 3698 final JoinPredecessorExpression lhs = (JoinPredecessorExpression)binaryNode.lhs(); 3699 final boolean lhsConvert = LocalVariableConversion.hasLiveConversion(lhs); 3700 final Label evalRhs = lhsConvert ? new Label("eval_rhs") : null; 3701 3702 loadExpression(lhs, outBounds).dup().convert(Type.BOOLEAN); 3703 if (isAnd) { 3704 if(lhsConvert) { 3705 method.ifne(evalRhs); 3706 } else { 3707 method.ifeq(skip); 3708 } 3709 } else if(lhsConvert) { 3710 method.ifeq(evalRhs); 3711 } else { 3712 method.ifne(skip); 3713 } 3714 3715 if(lhsConvert) { 3716 method.beforeJoinPoint(lhs); 3717 method._goto(skip); 3718 method.label(evalRhs); 3719 } 3720 3721 method.pop(); 3722 final JoinPredecessorExpression rhs = (JoinPredecessorExpression)binaryNode.rhs(); 3723 loadExpression(rhs, outBounds); 3724 method.beforeJoinPoint(rhs); 3725 method.label(skip); 3726 } 3727 3728 private static boolean isLocalVariable(final Expression lhs) { 3729 return lhs instanceof IdentNode && isLocalVariable((IdentNode)lhs); 3730 } 3731 3732 private static boolean isLocalVariable(final IdentNode lhs) { 3733 return lhs.getSymbol().isBytecodeLocal(); 3734 } 3735 3736 // NOTE: does not use resultBounds as the assignment is driven by the type of the RHS 3737 private void loadASSIGN(final BinaryNode binaryNode) { 3738 final Expression lhs = binaryNode.lhs(); 3739 final Expression rhs = binaryNode.rhs(); 3740 3741 final Type rhsType = rhs.getType(); 3742 // Detect dead assignments 3743 if(lhs instanceof IdentNode) { 3744 final Symbol symbol = ((IdentNode)lhs).getSymbol(); 3745 if(!symbol.isScope() && !symbol.hasSlotFor(rhsType) && lc.getCurrentDiscard() == binaryNode) { 3746 loadAndDiscard(rhs); 3747 lc.popDiscard(); 3748 method.markDeadLocalVariable(symbol); 3749 return; 3750 } 3751 } 3752 3753 new Store<BinaryNode>(binaryNode, lhs) { 3754 @Override 3755 protected void evaluate() { 3756 // NOTE: we're loading with "at least as wide as" so optimistic operations on the right hand side 3757 // remain optimistic, and then explicitly convert to the required type if needed. 3758 loadExpressionAsType(rhs, rhsType); 3759 } 3760 }.store(); 3761 } 3762 3763 /** 3764 * Binary self-assignment that can be optimistic: +=, -=, *=, and /=. 3765 */ 3766 private abstract class BinaryOptimisticSelfAssignment extends SelfModifyingStore<BinaryNode> { 3767 3768 /** 3769 * Constructor 3770 * 3771 * @param node the assign op node 3772 */ 3773 BinaryOptimisticSelfAssignment(final BinaryNode node) { 3774 super(node, node.lhs()); 3775 } 3776 3777 protected abstract void op(OptimisticOperation oo); 3778 3779 @Override 3780 protected void evaluate() { 3781 final Expression lhs = assignNode.lhs(); 3782 final Type widest = assignNode.isTokenType(TokenType.ASSIGN_ADD) ? Type.OBJECT : assignNode.getWidestOperationType(); 3783 final TypeBounds bounds = new TypeBounds(assignNode.getType(), widest); 3784 new OptimisticOperation(assignNode, bounds) { 3785 @Override 3786 void loadStack() { 3787 loadBinaryOperands(lhs, assignNode.rhs(), bounds, true); 3788 } 3789 @Override 3790 void consumeStack() { 3791 op(this); 3792 } 3793 }.emit(getOptimisticIgnoreCountForSelfModifyingExpression(lhs)); 3794 method.convert(assignNode.getType()); 3795 } 3796 } 3797 3798 /** 3799 * Non-optimistic binary self-assignment operation. Basically, everything except +=, -=, *=, and /=. 3800 */ 3801 private abstract class BinarySelfAssignment extends SelfModifyingStore<BinaryNode> { 3802 BinarySelfAssignment(final BinaryNode node) { 3803 super(node, node.lhs()); 3804 } 3805 3806 protected abstract void op(); 3807 3808 @Override 3809 protected void evaluate() { 3810 loadBinaryOperands(assignNode.lhs(), assignNode.rhs(), TypeBounds.UNBOUNDED.notWiderThan(assignNode.getWidestOperandType()), true); 3811 op(); 3812 } 3813 } 3814 3815 private void loadASSIGN_ADD(final BinaryNode binaryNode) { 3816 new BinaryOptimisticSelfAssignment(binaryNode) { 3817 @Override 3818 protected void op(final OptimisticOperation oo) { 3819 assert !(binaryNode.getType().isObject() && oo.isOptimistic); 3820 method.add(oo.getProgramPoint()); 3821 } 3822 }.store(); 3823 } 3824 3825 private void loadASSIGN_BIT_AND(final BinaryNode binaryNode) { 3826 new BinarySelfAssignment(binaryNode) { 3827 @Override 3828 protected void op() { 3829 method.and(); 3830 } 3831 }.store(); 3832 } 3833 3834 private void loadASSIGN_BIT_OR(final BinaryNode binaryNode) { 3835 new BinarySelfAssignment(binaryNode) { 3836 @Override 3837 protected void op() { 3838 method.or(); 3839 } 3840 }.store(); 3841 } 3842 3843 private void loadASSIGN_BIT_XOR(final BinaryNode binaryNode) { 3844 new BinarySelfAssignment(binaryNode) { 3845 @Override 3846 protected void op() { 3847 method.xor(); 3848 } 3849 }.store(); 3850 } 3851 3852 private void loadASSIGN_DIV(final BinaryNode binaryNode) { 3853 new BinaryOptimisticSelfAssignment(binaryNode) { 3854 @Override 3855 protected void op(final OptimisticOperation oo) { 3856 method.div(oo.getProgramPoint()); 3857 } 3858 }.store(); 3859 } 3860 3861 private void loadASSIGN_MOD(final BinaryNode binaryNode) { 3862 new BinaryOptimisticSelfAssignment(binaryNode) { 3863 @Override 3864 protected void op(final OptimisticOperation oo) { 3865 method.rem(oo.getProgramPoint()); 3866 } 3867 }.store(); 3868 } 3869 3870 private void loadASSIGN_MUL(final BinaryNode binaryNode) { 3871 new BinaryOptimisticSelfAssignment(binaryNode) { 3872 @Override 3873 protected void op(final OptimisticOperation oo) { 3874 method.mul(oo.getProgramPoint()); 3875 } 3876 }.store(); 3877 } 3878 3879 private void loadASSIGN_SAR(final BinaryNode binaryNode) { 3880 new BinarySelfAssignment(binaryNode) { 3881 @Override 3882 protected void op() { 3883 method.sar(); 3884 } 3885 }.store(); 3886 } 3887 3888 private void loadASSIGN_SHL(final BinaryNode binaryNode) { 3889 new BinarySelfAssignment(binaryNode) { 3890 @Override 3891 protected void op() { 3892 method.shl(); 3893 } 3894 }.store(); 3895 } 3896 3897 private void loadASSIGN_SHR(final BinaryNode binaryNode) { 3898 new BinarySelfAssignment(binaryNode) { 3899 @Override 3900 protected void op() { 3901 doSHR(); 3902 } 3903 3904 }.store(); 3905 } 3906 3907 private void doSHR() { 3908 // TODO: make SHR optimistic 3909 method.shr().convert(Type.LONG).load(JSType.MAX_UINT).and(); 3910 } 3911 3912 private void loadASSIGN_SUB(final BinaryNode binaryNode) { 3913 new BinaryOptimisticSelfAssignment(binaryNode) { 3914 @Override 3915 protected void op(final OptimisticOperation oo) { 3916 method.sub(oo.getProgramPoint()); 3917 } 3918 }.store(); 3919 } 3920 3921 /** 3922 * Helper class for binary arithmetic ops 3923 */ 3924 private abstract class BinaryArith { 3925 protected abstract void op(int programPoint); 3926 3927 protected void evaluate(final BinaryNode node, final TypeBounds resultBounds) { 3928 final TypeBounds numericBounds = resultBounds.booleanToInt().objectToNumber(); 3929 new OptimisticOperation(node, numericBounds) { 3930 @Override 3931 void loadStack() { 3932 final TypeBounds operandBounds; 3933 if(numericBounds.narrowest == Type.NUMBER) { 3934 // Result should be double always. Propagate it into the operands so we don't have lots of I2D 3935 // and L2D after operand evaluation. 3936 assert numericBounds.widest == Type.NUMBER; 3937 operandBounds = numericBounds; 3938 } else { 3939 final boolean isOptimistic = isValid(getProgramPoint()); 3940 if(isOptimistic) { 3941 operandBounds = new TypeBounds(node.getType(), Type.NUMBER); 3942 } else if(node.isTokenType(TokenType.DIV) || node.isTokenType(TokenType.MOD)) { 3943 // Non-optimistic division must always take double arguments as its result must also be 3944 // double. 3945 operandBounds = TypeBounds.NUMBER; 3946 } else { 3947 // Non-optimistic, non-FP subtraction or multiplication. Allow them to overflow. 3948 operandBounds = new TypeBounds(Type.narrowest(node.getWidestOperandType(), 3949 numericBounds.widest), Type.NUMBER); 3950 } 3951 } 3952 loadBinaryOperands(node.lhs(), node.rhs(), operandBounds, false); 3953 } 3954 3955 @Override 3956 void consumeStack() { 3957 op(getProgramPoint()); 3958 } 3959 }.emit(); 3960 } 3961 } 3962 3963 private void loadBIT_AND(final BinaryNode binaryNode) { 3964 loadBinaryOperands(binaryNode); 3965 method.and(); 3966 } 3967 3968 private void loadBIT_OR(final BinaryNode binaryNode) { 3969 loadBinaryOperands(binaryNode); 3970 method.or(); 3971 } 3972 3973 private void loadBIT_XOR(final BinaryNode binaryNode) { 3974 loadBinaryOperands(binaryNode); 3975 method.xor(); 3976 } 3977 3978 private void loadCOMMARIGHT(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3979 loadAndDiscard(binaryNode.lhs()); 3980 loadExpression(binaryNode.rhs(), resultBounds); 3981 } 3982 3983 private void loadCOMMALEFT(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3984 loadExpression(binaryNode.lhs(), resultBounds); 3985 loadAndDiscard(binaryNode.rhs()); 3986 } 3987 3988 private void loadDIV(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3989 new BinaryArith() { 3990 @Override 3991 protected void op(final int programPoint) { 3992 method.div(programPoint); 3993 } 3994 }.evaluate(binaryNode, resultBounds); 3995 } 3996 3997 private void loadCmp(final BinaryNode binaryNode, final Condition cond) { 3998 assert comparisonOperandsArePrimitive(binaryNode) : binaryNode; 3999 loadBinaryOperands(binaryNode); 4000 4001 final Label trueLabel = new Label("trueLabel"); 4002 final Label afterLabel = new Label("skip"); 4003 4004 method.conditionalJump(cond, trueLabel); 4005 4006 method.load(Boolean.FALSE); 4007 method._goto(afterLabel); 4008 method.label(trueLabel); 4009 method.load(Boolean.TRUE); 4010 method.label(afterLabel); 4011 } 4012 4013 private static boolean comparisonOperandsArePrimitive(final BinaryNode binaryNode) { 4014 final Type widest = Type.widest(binaryNode.lhs().getType(), binaryNode.rhs().getType()); 4015 return widest.isNumeric() || widest.isBoolean(); 4016 } 4017 4018 private void loadMOD(final BinaryNode binaryNode, final TypeBounds resultBounds) { 4019 new BinaryArith() { 4020 @Override 4021 protected void op(final int programPoint) { 4022 method.rem(programPoint); 4023 } 4024 }.evaluate(binaryNode, resultBounds); 4025 } 4026 4027 private void loadMUL(final BinaryNode binaryNode, final TypeBounds resultBounds) { 4028 new BinaryArith() { 4029 @Override 4030 protected void op(final int programPoint) { 4031 method.mul(programPoint); 4032 } 4033 }.evaluate(binaryNode, resultBounds); 4034 } 4035 4036 private void loadSAR(final BinaryNode binaryNode) { 4037 loadBinaryOperands(binaryNode); 4038 method.sar(); 4039 } 4040 4041 private void loadSHL(final BinaryNode binaryNode) { 4042 loadBinaryOperands(binaryNode); 4043 method.shl(); 4044 } 4045 4046 private void loadSHR(final BinaryNode binaryNode) { 4047 loadBinaryOperands(binaryNode); 4048 doSHR(); 4049 } 4050 4051 private void loadSUB(final BinaryNode binaryNode, final TypeBounds resultBounds) { 4052 new BinaryArith() { 4053 @Override 4054 protected void op(final int programPoint) { 4055 method.sub(programPoint); 4056 } 4057 }.evaluate(binaryNode, resultBounds); 4058 } 4059 4060 @Override 4061 public boolean enterLabelNode(final LabelNode labelNode) { 4062 labeledBlockBreakLiveLocals.push(lc.getUsedSlotCount()); 4063 return true; 4064 } 4065 4066 @Override 4067 protected boolean enterDefault(final Node node) { 4068 throw new AssertionError("Code generator entered node of type " + node.getClass().getName()); 4069 } 4070 4071 private void loadTernaryNode(final TernaryNode ternaryNode, final TypeBounds resultBounds) { 4072 final Expression test = ternaryNode.getTest(); 4073 final JoinPredecessorExpression trueExpr = ternaryNode.getTrueExpression(); 4074 final JoinPredecessorExpression falseExpr = ternaryNode.getFalseExpression(); 4075 4076 final Label falseLabel = new Label("ternary_false"); 4077 final Label exitLabel = new Label("ternary_exit"); 4078 4079 final Type outNarrowest = Type.narrowest(resultBounds.widest, Type.generic(Type.widestReturnType(trueExpr.getType(), falseExpr.getType()))); 4080 final TypeBounds outBounds = resultBounds.notNarrowerThan(outNarrowest); 4081 4082 emitBranch(test, falseLabel, false); 4083 4084 loadExpression(trueExpr.getExpression(), outBounds); 4085 assert Type.generic(method.peekType()) == outBounds.narrowest; 4086 method.beforeJoinPoint(trueExpr); 4087 method._goto(exitLabel); 4088 method.label(falseLabel); 4089 loadExpression(falseExpr.getExpression(), outBounds); 4090 assert Type.generic(method.peekType()) == outBounds.narrowest; 4091 method.beforeJoinPoint(falseExpr); 4092 method.label(exitLabel); 4093 } 4094 4095 /** 4096 * Generate all shared scope calls generated during codegen. 4097 */ 4098 void generateScopeCalls() { 4099 for (final SharedScopeCall scopeAccess : lc.getScopeCalls()) { 4100 scopeAccess.generateScopeCall(); 4101 } 4102 } 4103 4104 /** 4105 * Debug code used to print symbols 4106 * 4107 * @param block the block we are in 4108 * @param function the function we are in 4109 * @param ident identifier for block or function where applicable 4110 */ 4111 private void printSymbols(final Block block, final FunctionNode function, final String ident) { 4112 if (compiler.getScriptEnvironment()._print_symbols || function.getFlag(FunctionNode.IS_PRINT_SYMBOLS)) { 4113 final PrintWriter out = compiler.getScriptEnvironment().getErr(); 4114 out.println("[BLOCK in '" + ident + "']"); 4115 if (!block.printSymbols(out)) { 4116 out.println("<no symbols>"); 4117 } 4118 out.println(); 4119 } 4120 } 4121 4122 4123 /** 4124 * The difference between a store and a self modifying store is that 4125 * the latter may load part of the target on the stack, e.g. the base 4126 * of an AccessNode or the base and index of an IndexNode. These are used 4127 * both as target and as an extra source. Previously it was problematic 4128 * for self modifying stores if the target/lhs didn't belong to one 4129 * of three trivial categories: IdentNode, AcessNodes, IndexNodes. In that 4130 * case it was evaluated and tagged as "resolved", which meant at the second 4131 * time the lhs of this store was read (e.g. in a = a (second) + b for a += b, 4132 * it would be evaluated to a nop in the scope and cause stack underflow 4133 * 4134 * see NASHORN-703 4135 * 4136 * @param <T> 4137 */ 4138 private abstract class SelfModifyingStore<T extends Expression> extends Store<T> { 4139 protected SelfModifyingStore(final T assignNode, final Expression target) { 4140 super(assignNode, target); 4141 } 4142 4143 @Override 4144 protected boolean isSelfModifying() { 4145 return true; 4146 } 4147 } 4148 4149 /** 4150 * Helper class to generate stores 4151 */ 4152 private abstract class Store<T extends Expression> { 4153 4154 /** An assignment node, e.g. x += y */ 4155 protected final T assignNode; 4156 4157 /** The target node to store to, e.g. x */ 4158 private final Expression target; 4159 4160 /** How deep on the stack do the arguments go if this generates an indy call */ 4161 private int depth; 4162 4163 /** If we have too many arguments, we need temporary storage, this is stored in 'quick' */ 4164 private IdentNode quick; 4165 4166 /** 4167 * Constructor 4168 * 4169 * @param assignNode the node representing the whole assignment 4170 * @param target the target node of the assignment (destination) 4171 */ 4172 protected Store(final T assignNode, final Expression target) { 4173 this.assignNode = assignNode; 4174 this.target = target; 4175 } 4176 4177 /** 4178 * Constructor 4179 * 4180 * @param assignNode the node representing the whole assignment 4181 */ 4182 protected Store(final T assignNode) { 4183 this(assignNode, assignNode); 4184 } 4185 4186 /** 4187 * Is this a self modifying store operation, e.g. *= or ++ 4188 * @return true if self modifying store 4189 */ 4190 protected boolean isSelfModifying() { 4191 return false; 4192 } 4193 4194 private void prologue() { 4195 /** 4196 * This loads the parts of the target, e.g base and index. they are kept 4197 * on the stack throughout the store and used at the end to execute it 4198 */ 4199 4200 target.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 4201 @Override 4202 public boolean enterIdentNode(final IdentNode node) { 4203 if (node.getSymbol().isScope()) { 4204 method.loadCompilerConstant(SCOPE); 4205 depth += Type.SCOPE.getSlots(); 4206 assert depth == 1; 4207 } 4208 return false; 4209 } 4210 4211 private void enterBaseNode() { 4212 assert target instanceof BaseNode : "error - base node " + target + " must be instanceof BaseNode"; 4213 final BaseNode baseNode = (BaseNode)target; 4214 final Expression base = baseNode.getBase(); 4215 4216 loadExpressionAsObject(base); 4217 depth += Type.OBJECT.getSlots(); 4218 assert depth == 1; 4219 4220 if (isSelfModifying()) { 4221 method.dup(); 4222 } 4223 } 4224 4225 @Override 4226 public boolean enterAccessNode(final AccessNode node) { 4227 enterBaseNode(); 4228 return false; 4229 } 4230 4231 @Override 4232 public boolean enterIndexNode(final IndexNode node) { 4233 enterBaseNode(); 4234 4235 final Expression index = node.getIndex(); 4236 if (!index.getType().isNumeric()) { 4237 // could be boolean here as well 4238 loadExpressionAsObject(index); 4239 } else { 4240 loadExpressionUnbounded(index); 4241 } 4242 depth += index.getType().getSlots(); 4243 4244 if (isSelfModifying()) { 4245 //convert "base base index" to "base index base index" 4246 method.dup(1); 4247 } 4248 4249 return false; 4250 } 4251 4252 }); 4253 } 4254 4255 /** 4256 * Generates an extra local variable, always using the same slot, one that is available after the end of the 4257 * frame. 4258 * 4259 * @param type the type of the variable 4260 * 4261 * @return the quick variable 4262 */ 4263 private IdentNode quickLocalVariable(final Type type) { 4264 final String name = lc.getCurrentFunction().uniqueName(QUICK_PREFIX.symbolName()); 4265 final Symbol symbol = new Symbol(name, IS_INTERNAL | HAS_SLOT); 4266 symbol.setHasSlotFor(type); 4267 symbol.setFirstSlot(lc.quickSlot(type)); 4268 4269 final IdentNode quickIdent = IdentNode.createInternalIdentifier(symbol).setType(type); 4270 4271 return quickIdent; 4272 } 4273 4274 // store the result that "lives on" after the op, e.g. "i" in i++ postfix. 4275 protected void storeNonDiscard() { 4276 if (lc.getCurrentDiscard() == assignNode) { 4277 assert assignNode.isAssignment(); 4278 lc.popDiscard(); 4279 return; 4280 } 4281 4282 if (method.dup(depth) == null) { 4283 method.dup(); 4284 final Type quickType = method.peekType(); 4285 this.quick = quickLocalVariable(quickType); 4286 final Symbol quickSymbol = quick.getSymbol(); 4287 method.storeTemp(quickType, quickSymbol.getFirstSlot()); 4288 } 4289 } 4290 4291 private void epilogue() { 4292 /** 4293 * Take the original target args from the stack and use them 4294 * together with the value to be stored to emit the store code 4295 * 4296 * The case that targetSymbol is in scope (!hasSlot) and we actually 4297 * need to do a conversion on non-equivalent types exists, but is 4298 * very rare. See for example test/script/basic/access-specializer.js 4299 */ 4300 target.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 4301 @Override 4302 protected boolean enterDefault(final Node node) { 4303 throw new AssertionError("Unexpected node " + node + " in store epilogue"); 4304 } 4305 4306 @Override 4307 public boolean enterIdentNode(final IdentNode node) { 4308 final Symbol symbol = node.getSymbol(); 4309 assert symbol != null; 4310 if (symbol.isScope()) { 4311 final int flags = CALLSITE_SCOPE | getCallSiteFlags(); 4312 if (isFastScope(symbol)) { 4313 storeFastScopeVar(symbol, flags); 4314 } else { 4315 method.dynamicSet(node.getName(), flags); 4316 } 4317 } else { 4318 final Type storeType = assignNode.getType(); 4319 method.convert(storeType); 4320 storeIdentWithCatchConversion(node, storeType); 4321 } 4322 return false; 4323 4324 } 4325 4326 @Override 4327 public boolean enterAccessNode(final AccessNode node) { 4328 method.dynamicSet(node.getProperty(), getCallSiteFlags()); 4329 return false; 4330 } 4331 4332 @Override 4333 public boolean enterIndexNode(final IndexNode node) { 4334 method.dynamicSetIndex(getCallSiteFlags()); 4335 return false; 4336 } 4337 }); 4338 4339 4340 // whatever is on the stack now is the final answer 4341 } 4342 4343 protected abstract void evaluate(); 4344 4345 void store() { 4346 prologue(); 4347 evaluate(); // leaves an operation of whatever the operationType was on the stack 4348 storeNonDiscard(); 4349 epilogue(); 4350 if (quick != null) { 4351 method.load(quick); 4352 } 4353 } 4354 } 4355 4356 private void newFunctionObject(final FunctionNode functionNode, final boolean addInitializer) { 4357 assert lc.peek() == functionNode; 4358 4359 final int fnId = functionNode.getId(); 4360 4361 final RecompilableScriptFunctionData data = compiler.getScriptFunctionData(fnId); 4362 4363 assert data != null : functionNode.getName() + " has no data"; 4364 4365 if (functionNode.isProgram() && !compiler.isOnDemandCompilation()) { 4366 final CompileUnit fnUnit = functionNode.getCompileUnit(); 4367 final MethodEmitter createFunction = fnUnit.getClassEmitter().method( 4368 EnumSet.of(Flag.PUBLIC, Flag.STATIC), CREATE_PROGRAM_FUNCTION.symbolName(), 4369 ScriptFunction.class, ScriptObject.class); 4370 createFunction.begin(); 4371 createFunction._new(SCRIPTFUNCTION_IMPL_NAME, SCRIPTFUNCTION_IMPL_TYPE).dup(); 4372 loadConstant(data, fnUnit, createFunction); 4373 createFunction.load(SCOPE_TYPE, 0); 4374 createFunction.invoke(constructorNoLookup(SCRIPTFUNCTION_IMPL_NAME, RecompilableScriptFunctionData.class, ScriptObject.class)); 4375 createFunction._return(); 4376 createFunction.end(); 4377 } 4378 4379 if (addInitializer && !compiler.isOnDemandCompilation()) { 4380 compiler.addFunctionInitializer(data, functionNode); 4381 } 4382 4383 // We don't emit a ScriptFunction on stack for the outermost compiled function (as there's no code being 4384 // generated in its outer context that'd need it as a callee). 4385 if (lc.getOutermostFunction() == functionNode) { 4386 return; 4387 } 4388 4389 method._new(SCRIPTFUNCTION_IMPL_NAME, SCRIPTFUNCTION_IMPL_TYPE).dup(); 4390 loadConstant(data); 4391 4392 if (functionNode.needsParentScope()) { 4393 method.loadCompilerConstant(SCOPE); 4394 } else { 4395 method.loadNull(); 4396 } 4397 method.invoke(constructorNoLookup(SCRIPTFUNCTION_IMPL_NAME, RecompilableScriptFunctionData.class, ScriptObject.class)); 4398 } 4399 4400 // calls on Global class. 4401 private MethodEmitter globalInstance() { 4402 return method.invokestatic(GLOBAL_OBJECT, "instance", "()L" + GLOBAL_OBJECT + ';'); 4403 } 4404 4405 private MethodEmitter globalAllocateArguments() { 4406 return method.invokestatic(GLOBAL_OBJECT, "allocateArguments", methodDescriptor(ScriptObject.class, Object[].class, Object.class, int.class)); 4407 } 4408 4409 private MethodEmitter globalNewRegExp() { 4410 return method.invokestatic(GLOBAL_OBJECT, "newRegExp", methodDescriptor(Object.class, String.class, String.class)); 4411 } 4412 4413 private MethodEmitter globalRegExpCopy() { 4414 return method.invokestatic(GLOBAL_OBJECT, "regExpCopy", methodDescriptor(Object.class, Object.class)); 4415 } 4416 4417 private MethodEmitter globalAllocateArray(final ArrayType type) { 4418 //make sure the native array is treated as an array type 4419 return method.invokestatic(GLOBAL_OBJECT, "allocate", "(" + type.getDescriptor() + ")Ljdk/nashorn/internal/objects/NativeArray;"); 4420 } 4421 4422 private MethodEmitter globalIsEval() { 4423 return method.invokestatic(GLOBAL_OBJECT, "isEval", methodDescriptor(boolean.class, Object.class)); 4424 } 4425 4426 private MethodEmitter globalReplaceLocationPropertyPlaceholder() { 4427 return method.invokestatic(GLOBAL_OBJECT, "replaceLocationPropertyPlaceholder", methodDescriptor(Object.class, Object.class, Object.class)); 4428 } 4429 4430 private MethodEmitter globalCheckObjectCoercible() { 4431 return method.invokestatic(GLOBAL_OBJECT, "checkObjectCoercible", methodDescriptor(void.class, Object.class)); 4432 } 4433 4434 private MethodEmitter globalDirectEval() { 4435 return method.invokestatic(GLOBAL_OBJECT, "directEval", 4436 methodDescriptor(Object.class, Object.class, Object.class, Object.class, Object.class, boolean.class)); 4437 } 4438 4439 private abstract class OptimisticOperation { 4440 private final boolean isOptimistic; 4441 // expression and optimistic are the same reference 4442 private final Expression expression; 4443 private final Optimistic optimistic; 4444 private final TypeBounds resultBounds; 4445 4446 OptimisticOperation(final Optimistic optimistic, final TypeBounds resultBounds) { 4447 this.optimistic = optimistic; 4448 this.expression = (Expression)optimistic; 4449 this.resultBounds = resultBounds; 4450 this.isOptimistic = isOptimistic(optimistic) && useOptimisticTypes() && 4451 // Operation is only effectively optimistic if its type, after being coerced into the result bounds 4452 // is narrower than the upper bound. 4453 resultBounds.within(Type.generic(((Expression)optimistic).getType())).narrowerThan(resultBounds.widest); 4454 } 4455 4456 MethodEmitter emit() { 4457 return emit(0); 4458 } 4459 4460 MethodEmitter emit(final int ignoredArgCount) { 4461 final int programPoint = optimistic.getProgramPoint(); 4462 final boolean optimisticOrContinuation = isOptimistic || isContinuationEntryPoint(programPoint); 4463 final boolean currentContinuationEntryPoint = isCurrentContinuationEntryPoint(programPoint); 4464 final int stackSizeOnEntry = method.getStackSize() - ignoredArgCount; 4465 4466 // First store the values on the stack opportunistically into local variables. Doing it before loadStack() 4467 // allows us to not have to pop/load any arguments that are pushed onto it by loadStack() in the second 4468 // storeStack(). 4469 storeStack(ignoredArgCount, optimisticOrContinuation); 4470 4471 // Now, load the stack 4472 loadStack(); 4473 4474 // Now store the values on the stack ultimately into local variables. In vast majority of cases, this is 4475 // (aside from creating the local types map) a no-op, as the first opportunistic stack store will already 4476 // store all variables. However, there can be operations in the loadStack() that invalidate some of the 4477 // stack stores, e.g. in "x[i] = x[++i]", "++i" will invalidate the already stored value for "i". In such 4478 // unfortunate cases this second storeStack() will restore the invariant that everything on the stack is 4479 // stored into a local variable, although at the cost of doing a store/load on the loaded arguments as well. 4480 final int liveLocalsCount = storeStack(method.getStackSize() - stackSizeOnEntry, optimisticOrContinuation); 4481 assert optimisticOrContinuation == (liveLocalsCount != -1); 4482 4483 final Label beginTry; 4484 final Label catchLabel; 4485 final Label afterConsumeStack = isOptimistic || currentContinuationEntryPoint ? new Label("after_consume_stack") : null; 4486 if(isOptimistic) { 4487 beginTry = new Label("try_optimistic"); 4488 final String catchLabelName = (afterConsumeStack == null ? "" : afterConsumeStack.toString()) + "_handler"; 4489 catchLabel = new Label(catchLabelName); 4490 method.label(beginTry); 4491 } else { 4492 beginTry = catchLabel = null; 4493 } 4494 4495 consumeStack(); 4496 4497 if(isOptimistic) { 4498 method._try(beginTry, afterConsumeStack, catchLabel, UnwarrantedOptimismException.class); 4499 } 4500 4501 if(isOptimistic || currentContinuationEntryPoint) { 4502 method.label(afterConsumeStack); 4503 4504 final int[] localLoads = method.getLocalLoadsOnStack(0, stackSizeOnEntry); 4505 assert everyStackValueIsLocalLoad(localLoads) : Arrays.toString(localLoads) + ", " + stackSizeOnEntry + ", " + ignoredArgCount; 4506 final List<Type> localTypesList = method.getLocalVariableTypes(); 4507 final int usedLocals = method.getUsedSlotsWithLiveTemporaries(); 4508 final List<Type> localTypes = method.getWidestLiveLocals(localTypesList.subList(0, usedLocals)); 4509 assert everyLocalLoadIsValid(localLoads, usedLocals) : Arrays.toString(localLoads) + " ~ " + localTypes; 4510 4511 if(isOptimistic) { 4512 addUnwarrantedOptimismHandlerLabel(localTypes, catchLabel); 4513 } 4514 if(currentContinuationEntryPoint) { 4515 final ContinuationInfo ci = getContinuationInfo(); 4516 assert ci != null : "no continuation info found for " + lc.getCurrentFunction(); 4517 assert !ci.hasTargetLabel(); // No duplicate program points 4518 ci.setTargetLabel(afterConsumeStack); 4519 ci.getHandlerLabel().markAsOptimisticContinuationHandlerFor(afterConsumeStack); 4520 // Can't rely on targetLabel.stack.localVariableTypes.length, as it can be higher due to effectively 4521 // dead local variables. 4522 ci.lvarCount = localTypes.size(); 4523 ci.setStackStoreSpec(localLoads); 4524 ci.setStackTypes(Arrays.copyOf(method.getTypesFromStack(method.getStackSize()), stackSizeOnEntry)); 4525 assert ci.getStackStoreSpec().length == ci.getStackTypes().length; 4526 ci.setReturnValueType(method.peekType()); 4527 ci.lineNumber = getLastLineNumber(); 4528 ci.catchLabel = catchLabels.peek(); 4529 } 4530 } 4531 return method; 4532 } 4533 4534 /** 4535 * Stores the current contents of the stack into local variables so they are not lost before invoking something that 4536 * can result in an {@code UnwarantedOptimizationException}. 4537 * @param ignoreArgCount the number of topmost arguments on stack to ignore when deciding on the shape of the catch 4538 * block. Those are used in the situations when we could not place the call to {@code storeStack} early enough 4539 * (before emitting code for pushing the arguments that the optimistic call will pop). This is admittedly a 4540 * deficiency in the design of the code generator when it deals with self-assignments and we should probably look 4541 * into fixing it. 4542 * @return types of the significant local variables after the stack was stored (types for local variables used 4543 * for temporary storage of ignored arguments are not returned). 4544 * @param optimisticOrContinuation if false, this method should not execute 4545 * a label for a catch block for the {@code UnwarantedOptimizationException}, suitable for capturing the 4546 * currently live local variables, tailored to their types. 4547 */ 4548 private int storeStack(final int ignoreArgCount, final boolean optimisticOrContinuation) { 4549 if(!optimisticOrContinuation) { 4550 return -1; // NOTE: correct value to return is lc.getUsedSlotCount(), but it wouldn't be used anyway 4551 } 4552 4553 final int stackSize = method.getStackSize(); 4554 final Type[] stackTypes = method.getTypesFromStack(stackSize); 4555 final int[] localLoadsOnStack = method.getLocalLoadsOnStack(0, stackSize); 4556 final int usedSlots = method.getUsedSlotsWithLiveTemporaries(); 4557 4558 final int firstIgnored = stackSize - ignoreArgCount; 4559 // Find the first value on the stack (from the bottom) that is not a load from a local variable. 4560 int firstNonLoad = 0; 4561 while(firstNonLoad < firstIgnored && localLoadsOnStack[firstNonLoad] != Label.Stack.NON_LOAD) { 4562 firstNonLoad++; 4563 } 4564 4565 // Only do the store/load if first non-load is not an ignored argument. Otherwise, do nothing and return 4566 // the number of used slots as the number of live local variables. 4567 if(firstNonLoad >= firstIgnored) { 4568 return usedSlots; 4569 } 4570 4571 // Find the number of new temporary local variables that we need; it's the number of values on the stack that 4572 // are not direct loads of existing local variables. 4573 int tempSlotsNeeded = 0; 4574 for(int i = firstNonLoad; i < stackSize; ++i) { 4575 if(localLoadsOnStack[i] == Label.Stack.NON_LOAD) { 4576 tempSlotsNeeded += stackTypes[i].getSlots(); 4577 } 4578 } 4579 4580 // Ensure all values on the stack that weren't directly loaded from a local variable are stored in a local 4581 // variable. We're starting from highest local variable index, so that in case ignoreArgCount > 0 the ignored 4582 // ones end up at the end of the local variable table. 4583 int lastTempSlot = usedSlots + tempSlotsNeeded; 4584 int ignoreSlotCount = 0; 4585 for(int i = stackSize; i -- > firstNonLoad;) { 4586 final int loadSlot = localLoadsOnStack[i]; 4587 if(loadSlot == Label.Stack.NON_LOAD) { 4588 final Type type = stackTypes[i]; 4589 final int slots = type.getSlots(); 4590 lastTempSlot -= slots; 4591 if(i >= firstIgnored) { 4592 ignoreSlotCount += slots; 4593 } 4594 method.storeTemp(type, lastTempSlot); 4595 } else { 4596 method.pop(); 4597 } 4598 } 4599 assert lastTempSlot == usedSlots; // used all temporary locals 4600 4601 final List<Type> localTypesList = method.getLocalVariableTypes(); 4602 4603 // Load values back on stack. 4604 for(int i = firstNonLoad; i < stackSize; ++i) { 4605 final int loadSlot = localLoadsOnStack[i]; 4606 final Type stackType = stackTypes[i]; 4607 final boolean isLoad = loadSlot != Label.Stack.NON_LOAD; 4608 final int lvarSlot = isLoad ? loadSlot : lastTempSlot; 4609 final Type lvarType = localTypesList.get(lvarSlot); 4610 method.load(lvarType, lvarSlot); 4611 if(isLoad) { 4612 // Conversion operators (I2L etc.) preserve "load"-ness of the value despite the fact that, in the 4613 // strict sense they are creating a derived value from the loaded value. This special behavior of 4614 // on-stack conversion operators is necessary to accommodate for differences in local variable types 4615 // after deoptimization; having a conversion operator throw away "load"-ness would create different 4616 // local variable table shapes between optimism-failed code and its deoptimized rest-of method). 4617 // After we load the value back, we need to redo the conversion to the stack type if stack type is 4618 // different. 4619 // NOTE: this would only strictly be necessary for widening conversions (I2L, L2D, I2D), and not for 4620 // narrowing ones (L2I, D2L, D2I) as only widening conversions are the ones that can get eliminated 4621 // in a deoptimized method, as their original input argument got widened. Maybe experiment with 4622 // throwing away "load"-ness for narrowing conversions in MethodEmitter.convert()? 4623 method.convert(stackType); 4624 } else { 4625 // temporary stores never needs a convert, as their type is always the same as the stack type. 4626 assert lvarType == stackType; 4627 lastTempSlot += lvarType.getSlots(); 4628 } 4629 } 4630 // used all temporaries 4631 assert lastTempSlot == usedSlots + tempSlotsNeeded; 4632 4633 return lastTempSlot - ignoreSlotCount; 4634 } 4635 4636 private void addUnwarrantedOptimismHandlerLabel(final List<Type> localTypes, final Label label) { 4637 final String lvarTypesDescriptor = getLvarTypesDescriptor(localTypes); 4638 final Map<String, Collection<Label>> unwarrantedOptimismHandlers = lc.getUnwarrantedOptimismHandlers(); 4639 Collection<Label> labels = unwarrantedOptimismHandlers.get(lvarTypesDescriptor); 4640 if(labels == null) { 4641 labels = new LinkedList<>(); 4642 unwarrantedOptimismHandlers.put(lvarTypesDescriptor, labels); 4643 } 4644 method.markLabelAsOptimisticCatchHandler(label, localTypes.size()); 4645 labels.add(label); 4646 } 4647 4648 abstract void loadStack(); 4649 4650 // Make sure that whatever indy call site you emit from this method uses {@code getCallSiteFlagsOptimistic(node)} 4651 // or otherwise ensure optimistic flag is correctly set in the call site, otherwise it doesn't make much sense 4652 // to use OptimisticExpression for emitting it. 4653 abstract void consumeStack(); 4654 4655 /** 4656 * Emits the correct dynamic getter code. Normally just delegates to method emitter, except when the target 4657 * expression is optimistic, and the desired type is narrower than the optimistic type. In that case, it'll emit a 4658 * dynamic getter with its original optimistic type, and explicitly insert a narrowing conversion. This way we can 4659 * preserve the optimism of the values even if they're subsequently immediately coerced into a narrower type. This 4660 * is beneficial because in this case we can still presume that since the original getter was optimistic, the 4661 * conversion has no side effects. 4662 * @param name the name of the property being get 4663 * @param flags call site flags 4664 * @param isMethod whether we're preferrably retrieving a function 4665 * @return the current method emitter 4666 */ 4667 MethodEmitter dynamicGet(final String name, final int flags, final boolean isMethod) { 4668 if(isOptimistic) { 4669 return method.dynamicGet(getOptimisticCoercedType(), name, getOptimisticFlags(flags), isMethod); 4670 } 4671 return method.dynamicGet(resultBounds.within(expression.getType()), name, nonOptimisticFlags(flags), isMethod); 4672 } 4673 4674 MethodEmitter dynamicGetIndex(final int flags, final boolean isMethod) { 4675 if(isOptimistic) { 4676 return method.dynamicGetIndex(getOptimisticCoercedType(), getOptimisticFlags(flags), isMethod); 4677 } 4678 return method.dynamicGetIndex(resultBounds.within(expression.getType()), nonOptimisticFlags(flags), isMethod); 4679 } 4680 4681 MethodEmitter dynamicCall(final int argCount, final int flags) { 4682 if (isOptimistic) { 4683 return method.dynamicCall(getOptimisticCoercedType(), argCount, getOptimisticFlags(flags)); 4684 } 4685 return method.dynamicCall(resultBounds.within(expression.getType()), argCount, nonOptimisticFlags(flags)); 4686 } 4687 4688 int getOptimisticFlags(final int flags) { 4689 return flags | CALLSITE_OPTIMISTIC | (optimistic.getProgramPoint() << CALLSITE_PROGRAM_POINT_SHIFT); //encode program point in high bits 4690 } 4691 4692 int getProgramPoint() { 4693 return isOptimistic ? optimistic.getProgramPoint() : INVALID_PROGRAM_POINT; 4694 } 4695 4696 void convertOptimisticReturnValue() { 4697 if (isOptimistic) { 4698 final Type optimisticType = getOptimisticCoercedType(); 4699 if(!optimisticType.isObject()) { 4700 method.load(optimistic.getProgramPoint()); 4701 if(optimisticType.isInteger()) { 4702 method.invoke(ENSURE_INT); 4703 } else if(optimisticType.isLong()) { 4704 method.invoke(ENSURE_LONG); 4705 } else if(optimisticType.isNumber()) { 4706 method.invoke(ENSURE_NUMBER); 4707 } else { 4708 throw new AssertionError(optimisticType); 4709 } 4710 } 4711 } 4712 } 4713 4714 void replaceCompileTimeProperty() { 4715 final IdentNode identNode = (IdentNode)expression; 4716 final String name = identNode.getSymbol().getName(); 4717 if (CompilerConstants.__FILE__.name().equals(name)) { 4718 replaceCompileTimeProperty(getCurrentSource().getName()); 4719 } else if (CompilerConstants.__DIR__.name().equals(name)) { 4720 replaceCompileTimeProperty(getCurrentSource().getBase()); 4721 } else if (CompilerConstants.__LINE__.name().equals(name)) { 4722 replaceCompileTimeProperty(getCurrentSource().getLine(identNode.position())); 4723 } 4724 } 4725 4726 /** 4727 * When an ident with name __FILE__, __DIR__, or __LINE__ is loaded, we'll try to look it up as any other 4728 * identifier. However, if it gets all the way up to the Global object, it will send back a special value that 4729 * represents a placeholder for these compile-time location properties. This method will generate code that loads 4730 * the value of the compile-time location property and then invokes a method in Global that will replace the 4731 * placeholder with the value. Effectively, if the symbol for these properties is defined anywhere in the lexical 4732 * scope, they take precedence, but if they aren't, then they resolve to the compile-time location property. 4733 * @param propertyValue the actual value of the property 4734 */ 4735 private void replaceCompileTimeProperty(final Object propertyValue) { 4736 assert method.peekType().isObject(); 4737 if(propertyValue instanceof String || propertyValue == null) { 4738 method.load((String)propertyValue); 4739 } else if(propertyValue instanceof Integer) { 4740 method.load(((Integer)propertyValue).intValue()); 4741 method.convert(Type.OBJECT); 4742 } else { 4743 throw new AssertionError(); 4744 } 4745 globalReplaceLocationPropertyPlaceholder(); 4746 convertOptimisticReturnValue(); 4747 } 4748 4749 /** 4750 * Returns the type that should be used as the return type of the dynamic invocation that is emitted as the code 4751 * for the current optimistic operation. If the type bounds is exact boolean or narrower than the expression's 4752 * optimistic type, then the optimistic type is returned, otherwise the coercing type. Effectively, this method 4753 * allows for moving the coercion into the optimistic type when it won't adversely affect the optimistic 4754 * evaluation semantics, and for preserving the optimistic type and doing a separate coercion when it would 4755 * affect it. 4756 * @return 4757 */ 4758 private Type getOptimisticCoercedType() { 4759 final Type optimisticType = expression.getType(); 4760 assert resultBounds.widest.widerThan(optimisticType); 4761 final Type narrowest = resultBounds.narrowest; 4762 4763 if(narrowest.isBoolean() || narrowest.narrowerThan(optimisticType)) { 4764 assert !optimisticType.isObject(); 4765 return optimisticType; 4766 } 4767 assert !narrowest.isObject(); 4768 return narrowest; 4769 } 4770 } 4771 4772 private static boolean isOptimistic(final Optimistic optimistic) { 4773 if(!optimistic.canBeOptimistic()) { 4774 return false; 4775 } 4776 final Expression expr = (Expression)optimistic; 4777 return expr.getType().narrowerThan(expr.getWidestOperationType()); 4778 } 4779 4780 private static boolean everyLocalLoadIsValid(final int[] loads, final int localCount) { 4781 for (final int load : loads) { 4782 if(load < 0 || load >= localCount) { 4783 return false; 4784 } 4785 } 4786 return true; 4787 } 4788 4789 private static boolean everyStackValueIsLocalLoad(final int[] loads) { 4790 for (final int load : loads) { 4791 if(load == Label.Stack.NON_LOAD) { 4792 return false; 4793 } 4794 } 4795 return true; 4796 } 4797 4798 private String getLvarTypesDescriptor(final List<Type> localVarTypes) { 4799 final int count = localVarTypes.size(); 4800 final StringBuilder desc = new StringBuilder(count); 4801 for(int i = 0; i < count;) { 4802 i += appendType(desc, localVarTypes.get(i)); 4803 } 4804 return method.markSymbolBoundariesInLvarTypesDescriptor(desc.toString()); 4805 } 4806 4807 private static int appendType(final StringBuilder b, final Type t) { 4808 b.append(t.getBytecodeStackType()); 4809 return t.getSlots(); 4810 } 4811 4812 private static int countSymbolsInLvarTypeDescriptor(final String lvarTypeDescriptor) { 4813 int count = 0; 4814 for(int i = 0; i < lvarTypeDescriptor.length(); ++i) { 4815 if(Character.isUpperCase(lvarTypeDescriptor.charAt(i))) { 4816 ++count; 4817 } 4818 } 4819 return count; 4820 4821 } 4822 /** 4823 * Generates all the required {@code UnwarrantedOptimismException} handlers for the current function. The employed 4824 * strategy strives to maximize code reuse. Every handler constructs an array to hold the local variables, then 4825 * fills in some trailing part of the local variables (those for which it has a unique suffix in the descriptor), 4826 * then jumps to a handler for a prefix that's shared with other handlers. A handler that fills up locals up to 4827 * position 0 will not jump to a prefix handler (as it has no prefix), but instead end with constructing and 4828 * throwing a {@code RewriteException}. Since we lexicographically sort the entries, we only need to check every 4829 * entry to its immediately preceding one for longest matching prefix. 4830 * @return true if there is at least one exception handler 4831 */ 4832 private boolean generateUnwarrantedOptimismExceptionHandlers(final FunctionNode fn) { 4833 if(!useOptimisticTypes()) { 4834 return false; 4835 } 4836 4837 // Take the mapping of lvarSpecs -> labels, and turn them into a descending lexicographically sorted list of 4838 // handler specifications. 4839 final Map<String, Collection<Label>> unwarrantedOptimismHandlers = lc.popUnwarrantedOptimismHandlers(); 4840 if(unwarrantedOptimismHandlers.isEmpty()) { 4841 return false; 4842 } 4843 4844 method.lineNumber(0); 4845 4846 final List<OptimismExceptionHandlerSpec> handlerSpecs = new ArrayList<>(unwarrantedOptimismHandlers.size() * 4/3); 4847 for(final String spec: unwarrantedOptimismHandlers.keySet()) { 4848 handlerSpecs.add(new OptimismExceptionHandlerSpec(spec, true)); 4849 } 4850 Collections.sort(handlerSpecs, Collections.reverseOrder()); 4851 4852 // Map of local variable specifications to labels for populating the array for that local variable spec. 4853 final Map<String, Label> delegationLabels = new HashMap<>(); 4854 4855 // Do everything in a single pass over the handlerSpecs list. Note that the list can actually grow as we're 4856 // passing through it as we might add new prefix handlers into it, so can't hoist size() outside of the loop. 4857 for(int handlerIndex = 0; handlerIndex < handlerSpecs.size(); ++handlerIndex) { 4858 final OptimismExceptionHandlerSpec spec = handlerSpecs.get(handlerIndex); 4859 final String lvarSpec = spec.lvarSpec; 4860 if(spec.catchTarget) { 4861 assert !method.isReachable(); 4862 // Start a catch block and assign the labels for this lvarSpec with it. 4863 method._catch(unwarrantedOptimismHandlers.get(lvarSpec)); 4864 // This spec is a catch target, so emit array creation code. The length of the array is the number of 4865 // symbols - the number of uppercase characters. 4866 method.load(countSymbolsInLvarTypeDescriptor(lvarSpec)); 4867 method.newarray(Type.OBJECT_ARRAY); 4868 } 4869 if(spec.delegationTarget) { 4870 // If another handler can delegate to this handler as its prefix, then put a jump target here for the 4871 // shared code (after the array creation code, which is never shared). 4872 method.label(delegationLabels.get(lvarSpec)); // label must exist 4873 } 4874 4875 final boolean lastHandler = handlerIndex == handlerSpecs.size() - 1; 4876 4877 int lvarIndex; 4878 final int firstArrayIndex; 4879 final int firstLvarIndex; 4880 Label delegationLabel; 4881 final String commonLvarSpec; 4882 if(lastHandler) { 4883 // Last handler block, doesn't delegate to anything. 4884 lvarIndex = 0; 4885 firstLvarIndex = 0; 4886 firstArrayIndex = 0; 4887 delegationLabel = null; 4888 commonLvarSpec = null; 4889 } else { 4890 // Not yet the last handler block, will definitely delegate to another handler; let's figure out which 4891 // one. It can be an already declared handler further down the list, or it might need to declare a new 4892 // prefix handler. 4893 4894 // Since we're lexicographically ordered, the common prefix handler is defined by the common prefix of 4895 // this handler and the next handler on the list. 4896 final int nextHandlerIndex = handlerIndex + 1; 4897 final String nextLvarSpec = handlerSpecs.get(nextHandlerIndex).lvarSpec; 4898 commonLvarSpec = commonPrefix(lvarSpec, nextLvarSpec); 4899 // We don't chop symbols in half 4900 assert Character.isUpperCase(commonLvarSpec.charAt(commonLvarSpec.length() - 1)); 4901 4902 // Let's find if we already have a declaration for such handler, or we need to insert it. 4903 { 4904 boolean addNewHandler = true; 4905 int commonHandlerIndex = nextHandlerIndex; 4906 for(; commonHandlerIndex < handlerSpecs.size(); ++commonHandlerIndex) { 4907 final OptimismExceptionHandlerSpec forwardHandlerSpec = handlerSpecs.get(commonHandlerIndex); 4908 final String forwardLvarSpec = forwardHandlerSpec.lvarSpec; 4909 if(forwardLvarSpec.equals(commonLvarSpec)) { 4910 // We already have a handler for the common prefix. 4911 addNewHandler = false; 4912 // Make sure we mark it as a delegation target. 4913 forwardHandlerSpec.delegationTarget = true; 4914 break; 4915 } else if(!forwardLvarSpec.startsWith(commonLvarSpec)) { 4916 break; 4917 } 4918 } 4919 if(addNewHandler) { 4920 // We need to insert a common prefix handler. Note handlers created with catchTarget == false 4921 // will automatically have delegationTarget == true (because that's the only reason for their 4922 // existence). 4923 handlerSpecs.add(commonHandlerIndex, new OptimismExceptionHandlerSpec(commonLvarSpec, false)); 4924 } 4925 } 4926 4927 firstArrayIndex = countSymbolsInLvarTypeDescriptor(commonLvarSpec); 4928 lvarIndex = 0; 4929 for(int j = 0; j < commonLvarSpec.length(); ++j) { 4930 lvarIndex += CodeGeneratorLexicalContext.getTypeForSlotDescriptor(commonLvarSpec.charAt(j)).getSlots(); 4931 } 4932 firstLvarIndex = lvarIndex; 4933 4934 // Create a delegation label if not already present 4935 delegationLabel = delegationLabels.get(commonLvarSpec); 4936 if(delegationLabel == null) { 4937 // uo_pa == "unwarranted optimism, populate array" 4938 delegationLabel = new Label("uo_pa_" + commonLvarSpec); 4939 delegationLabels.put(commonLvarSpec, delegationLabel); 4940 } 4941 } 4942 4943 // Load local variables handled by this handler on stack 4944 int args = 0; 4945 boolean symbolHadValue = false; 4946 for(int typeIndex = commonLvarSpec == null ? 0 : commonLvarSpec.length(); typeIndex < lvarSpec.length(); ++typeIndex) { 4947 final char typeDesc = lvarSpec.charAt(typeIndex); 4948 final Type lvarType = CodeGeneratorLexicalContext.getTypeForSlotDescriptor(typeDesc); 4949 if (!lvarType.isUnknown()) { 4950 method.load(lvarType, lvarIndex); 4951 symbolHadValue = true; 4952 args++; 4953 } else if(typeDesc == 'U' && !symbolHadValue) { 4954 // Symbol boundary with undefined last value. Check if all previous values for this symbol were also 4955 // undefined; if so, emit one explicit Undefined. This serves to ensure that we're emiting exactly 4956 // one value for every symbol that uses local slots. While we could in theory ignore symbols that 4957 // are undefined (in other words, dead) at the point where this exception was thrown, unfortunately 4958 // we can't do it in practice. The reason for this is that currently our liveness analysis is 4959 // coarse (it can determine whether a symbol has not been read with a particular type anywhere in 4960 // the function being compiled, but that's it), and a symbol being promoted to Object due to a 4961 // deoptimization will suddenly show up as "live for Object type", and previously dead U->O 4962 // conversions on loop entries will suddenly become alive in the deoptimized method which will then 4963 // expect a value for that slot in its continuation handler. If we had precise liveness analysis, we 4964 // could go back to excluding known dead symbols from the payload of the RewriteException. 4965 if(method.peekType() == Type.UNDEFINED) { 4966 method.dup(); 4967 } else { 4968 method.loadUndefined(Type.OBJECT); 4969 } 4970 args++; 4971 } 4972 if(Character.isUpperCase(typeDesc)) { 4973 // Reached symbol boundary; reset flag for the next symbol. 4974 symbolHadValue = false; 4975 } 4976 lvarIndex += lvarType.getSlots(); 4977 } 4978 assert args > 0; 4979 // Delegate actual storing into array to an array populator utility method. 4980 //on the stack: 4981 // object array to be populated 4982 // start index 4983 // a lot of types 4984 method.dynamicArrayPopulatorCall(args + 1, firstArrayIndex); 4985 if(delegationLabel != null) { 4986 // We cascade to a prefix handler to fill out the rest of the local variables and throw the 4987 // RewriteException. 4988 assert !lastHandler; 4989 assert commonLvarSpec != null; 4990 // Must undefine the local variables that we have already processed for the sake of correct join on the 4991 // delegate label 4992 method.undefineLocalVariables(firstLvarIndex, true); 4993 final OptimismExceptionHandlerSpec nextSpec = handlerSpecs.get(handlerIndex + 1); 4994 // If the delegate immediately follows, and it's not a catch target (so it doesn't have array setup 4995 // code) don't bother emitting a jump, as we'd just jump to the next instruction. 4996 if(!nextSpec.lvarSpec.equals(commonLvarSpec) || nextSpec.catchTarget) { 4997 method._goto(delegationLabel); 4998 } 4999 } else { 5000 assert lastHandler; 5001 // Nothing to delegate to, so this handler must create and throw the RewriteException. 5002 // At this point we have the UnwarrantedOptimismException and the Object[] with local variables on 5003 // stack. We need to create a RewriteException, push two references to it below the constructor 5004 // arguments, invoke the constructor, and throw the exception. 5005 loadConstant(getByteCodeSymbolNames(fn)); 5006 if (isRestOf()) { 5007 loadConstant(getContinuationEntryPoints()); 5008 method.invoke(CREATE_REWRITE_EXCEPTION_REST_OF); 5009 } else { 5010 method.invoke(CREATE_REWRITE_EXCEPTION); 5011 } 5012 method.athrow(); 5013 } 5014 } 5015 return true; 5016 } 5017 5018 private static String[] getByteCodeSymbolNames(final FunctionNode fn) { 5019 // Only names of local variables on the function level are captured. This information is used to reduce 5020 // deoptimizations, so as much as we can capture will help. We rely on the fact that function wide variables are 5021 // all live all the time, so the array passed to rewrite exception contains one element for every slotted symbol 5022 // here. 5023 final List<String> names = new ArrayList<>(); 5024 for (final Symbol symbol: fn.getBody().getSymbols()) { 5025 if (symbol.hasSlot()) { 5026 if (symbol.isScope()) { 5027 // slot + scope can only be true for parameters 5028 assert symbol.isParam(); 5029 names.add(null); 5030 } else { 5031 names.add(symbol.getName()); 5032 } 5033 } 5034 } 5035 return names.toArray(new String[names.size()]); 5036 } 5037 5038 private static String commonPrefix(final String s1, final String s2) { 5039 final int l1 = s1.length(); 5040 final int l = Math.min(l1, s2.length()); 5041 int lms = -1; // last matching symbol 5042 for(int i = 0; i < l; ++i) { 5043 final char c1 = s1.charAt(i); 5044 if(c1 != s2.charAt(i)) { 5045 return s1.substring(0, lms + 1); 5046 } else if(Character.isUpperCase(c1)) { 5047 lms = i; 5048 } 5049 } 5050 return l == l1 ? s1 : s2; 5051 } 5052 5053 private static class OptimismExceptionHandlerSpec implements Comparable<OptimismExceptionHandlerSpec> { 5054 private final String lvarSpec; 5055 private final boolean catchTarget; 5056 private boolean delegationTarget; 5057 5058 OptimismExceptionHandlerSpec(final String lvarSpec, final boolean catchTarget) { 5059 this.lvarSpec = lvarSpec; 5060 this.catchTarget = catchTarget; 5061 if(!catchTarget) { 5062 delegationTarget = true; 5063 } 5064 } 5065 5066 @Override 5067 public int compareTo(final OptimismExceptionHandlerSpec o) { 5068 return lvarSpec.compareTo(o.lvarSpec); 5069 } 5070 5071 @Override 5072 public String toString() { 5073 final StringBuilder b = new StringBuilder(64).append("[HandlerSpec ").append(lvarSpec); 5074 if(catchTarget) { 5075 b.append(", catchTarget"); 5076 } 5077 if(delegationTarget) { 5078 b.append(", delegationTarget"); 5079 } 5080 return b.append("]").toString(); 5081 } 5082 } 5083 5084 private static class ContinuationInfo { 5085 private final Label handlerLabel; 5086 private Label targetLabel; // Label for the target instruction. 5087 int lvarCount; 5088 // Indices of local variables that need to be loaded on the stack when this node completes 5089 private int[] stackStoreSpec; 5090 // Types of values loaded on the stack 5091 private Type[] stackTypes; 5092 // If non-null, this node should perform the requisite type conversion 5093 private Type returnValueType; 5094 // If we are in the middle of an object literal initialization, we need to update the map 5095 private PropertyMap objectLiteralMap; 5096 // Object literal stack depth for object literal - not necessarly top if property is a tree 5097 private int objectLiteralStackDepth = -1; 5098 // The line number at the continuation point 5099 private int lineNumber; 5100 // The active catch label, in case the continuation point is in a try/catch block 5101 private Label catchLabel; 5102 // The number of scopes that need to be popped before control is transferred to the catch label. 5103 private int exceptionScopePops; 5104 5105 ContinuationInfo() { 5106 this.handlerLabel = new Label("continuation_handler"); 5107 } 5108 5109 Label getHandlerLabel() { 5110 return handlerLabel; 5111 } 5112 5113 boolean hasTargetLabel() { 5114 return targetLabel != null; 5115 } 5116 5117 Label getTargetLabel() { 5118 return targetLabel; 5119 } 5120 5121 void setTargetLabel(final Label targetLabel) { 5122 this.targetLabel = targetLabel; 5123 } 5124 5125 int[] getStackStoreSpec() { 5126 return stackStoreSpec.clone(); 5127 } 5128 5129 void setStackStoreSpec(final int[] stackStoreSpec) { 5130 this.stackStoreSpec = stackStoreSpec; 5131 } 5132 5133 Type[] getStackTypes() { 5134 return stackTypes.clone(); 5135 } 5136 5137 void setStackTypes(final Type[] stackTypes) { 5138 this.stackTypes = stackTypes; 5139 } 5140 5141 Type getReturnValueType() { 5142 return returnValueType; 5143 } 5144 5145 void setReturnValueType(final Type returnValueType) { 5146 this.returnValueType = returnValueType; 5147 } 5148 5149 int getObjectLiteralStackDepth() { 5150 return objectLiteralStackDepth; 5151 } 5152 5153 void setObjectLiteralStackDepth(final int objectLiteralStackDepth) { 5154 this.objectLiteralStackDepth = objectLiteralStackDepth; 5155 } 5156 5157 PropertyMap getObjectLiteralMap() { 5158 return objectLiteralMap; 5159 } 5160 5161 void setObjectLiteralMap(final PropertyMap objectLiteralMap) { 5162 this.objectLiteralMap = objectLiteralMap; 5163 } 5164 5165 @Override 5166 public String toString() { 5167 return "[localVariableTypes=" + targetLabel.getStack().getLocalVariableTypesCopy() + ", stackStoreSpec=" + 5168 Arrays.toString(stackStoreSpec) + ", returnValueType=" + returnValueType + "]"; 5169 } 5170 } 5171 5172 private ContinuationInfo getContinuationInfo() { 5173 return fnIdToContinuationInfo.get(lc.getCurrentFunction().getId()); 5174 } 5175 5176 private void generateContinuationHandler() { 5177 if (!isRestOf()) { 5178 return; 5179 } 5180 5181 final ContinuationInfo ci = getContinuationInfo(); 5182 method.label(ci.getHandlerLabel()); 5183 5184 // There should never be an exception thrown from the continuation handler, but in case there is (meaning, 5185 // Nashorn has a bug), then line number 0 will be an indication of where it came from (line numbers are Uint16). 5186 method.lineNumber(0); 5187 5188 final Label.Stack stack = ci.getTargetLabel().getStack(); 5189 final List<Type> lvarTypes = stack.getLocalVariableTypesCopy(); 5190 final BitSet symbolBoundary = stack.getSymbolBoundaryCopy(); 5191 final int lvarCount = ci.lvarCount; 5192 5193 final Type rewriteExceptionType = Type.typeFor(RewriteException.class); 5194 // Store the RewriteException into an unused local variable slot. 5195 method.load(rewriteExceptionType, 0); 5196 method.storeTemp(rewriteExceptionType, lvarCount); 5197 // Get local variable array 5198 method.load(rewriteExceptionType, 0); 5199 method.invoke(RewriteException.GET_BYTECODE_SLOTS); 5200 // Store local variables. Note that deoptimization might introduce new value types for existing local variables, 5201 // so we must use both liveLocals and symbolBoundary, as in some cases (when the continuation is inside of a try 5202 // block) we need to store the incoming value into multiple slots. The optimism exception handlers will have 5203 // exactly one array element for every symbol that uses bytecode storage. If in the originating method the value 5204 // was undefined, there will be an explicit Undefined value in the array. 5205 int arrayIndex = 0; 5206 for(int lvarIndex = 0; lvarIndex < lvarCount;) { 5207 final Type lvarType = lvarTypes.get(lvarIndex); 5208 if(!lvarType.isUnknown()) { 5209 method.dup(); 5210 method.load(arrayIndex).arrayload(); 5211 final Class<?> typeClass = lvarType.getTypeClass(); 5212 // Deoptimization in array initializers can cause arrays to undergo component type widening 5213 if(typeClass == long[].class) { 5214 method.load(rewriteExceptionType, lvarCount); 5215 method.invoke(RewriteException.TO_LONG_ARRAY); 5216 } else if(typeClass == double[].class) { 5217 method.load(rewriteExceptionType, lvarCount); 5218 method.invoke(RewriteException.TO_DOUBLE_ARRAY); 5219 } else if(typeClass == Object[].class) { 5220 method.load(rewriteExceptionType, lvarCount); 5221 method.invoke(RewriteException.TO_OBJECT_ARRAY); 5222 } else { 5223 if(!(typeClass.isPrimitive() || typeClass == Object.class)) { 5224 // NOTE: this can only happen with dead stores. E.g. for the program "1; []; f();" in which the 5225 // call to f() will deoptimize the call site, but it'll expect :return to have the type 5226 // NativeArray. However, in the more optimal version, :return's only live type is int, therefore 5227 // "{O}:return = []" is a dead store, and the variable will be sent into the continuation as 5228 // Undefined, however NativeArray can't hold Undefined instance. 5229 method.loadType(Type.getInternalName(typeClass)); 5230 method.invoke(RewriteException.INSTANCE_OR_NULL); 5231 } 5232 method.convert(lvarType); 5233 } 5234 method.storeHidden(lvarType, lvarIndex, false); 5235 } 5236 final int nextLvarIndex = lvarIndex + lvarType.getSlots(); 5237 if(symbolBoundary.get(nextLvarIndex - 1)) { 5238 ++arrayIndex; 5239 } 5240 lvarIndex = nextLvarIndex; 5241 } 5242 if(assertsEnabled) { 5243 method.load(arrayIndex); 5244 method.invoke(RewriteException.ASSERT_ARRAY_LENGTH); 5245 } else { 5246 method.pop(); 5247 } 5248 5249 final int[] stackStoreSpec = ci.getStackStoreSpec(); 5250 final Type[] stackTypes = ci.getStackTypes(); 5251 final boolean isStackEmpty = stackStoreSpec.length == 0; 5252 boolean replacedObjectLiteralMap = false; 5253 if(!isStackEmpty) { 5254 // Load arguments on the stack 5255 final int objectLiteralStackDepth = ci.getObjectLiteralStackDepth(); 5256 for(int i = 0; i < stackStoreSpec.length; ++i) { 5257 final int slot = stackStoreSpec[i]; 5258 method.load(lvarTypes.get(slot), slot); 5259 method.convert(stackTypes[i]); 5260 // stack: s0=object literal being initialized 5261 // change map of s0 so that the property we are initilizing when we failed 5262 // is now ci.returnValueType 5263 if (i == objectLiteralStackDepth) { 5264 method.dup(); 5265 assert ci.getObjectLiteralMap() != null; 5266 assert ScriptObject.class.isAssignableFrom(method.peekType().getTypeClass()) : method.peekType().getTypeClass() + " is not a script object"; 5267 loadConstant(ci.getObjectLiteralMap()); 5268 method.invoke(ScriptObject.SET_MAP); 5269 replacedObjectLiteralMap = true; 5270 } 5271 } 5272 } 5273 // Must have emitted the code for replacing the map of an object literal if we have a set object literal stack depth 5274 assert ci.getObjectLiteralStackDepth() == -1 || replacedObjectLiteralMap; 5275 // Load RewriteException back. 5276 method.load(rewriteExceptionType, lvarCount); 5277 // Get rid of the stored reference 5278 method.loadNull(); 5279 method.storeHidden(Type.OBJECT, lvarCount); 5280 // Mark it dead 5281 method.markDeadSlots(lvarCount, Type.OBJECT.getSlots()); 5282 5283 // Load return value on the stack 5284 method.invoke(RewriteException.GET_RETURN_VALUE); 5285 5286 final Type returnValueType = ci.getReturnValueType(); 5287 5288 // Set up an exception handler for primitive type conversion of return value if needed 5289 boolean needsCatch = false; 5290 final Label targetCatchLabel = ci.catchLabel; 5291 Label _try = null; 5292 if(returnValueType.isPrimitive()) { 5293 // If the conversion throws an exception, we want to report the line number of the continuation point. 5294 method.lineNumber(ci.lineNumber); 5295 5296 if(targetCatchLabel != METHOD_BOUNDARY) { 5297 _try = new Label(""); 5298 method.label(_try); 5299 needsCatch = true; 5300 } 5301 } 5302 5303 // Convert return value 5304 method.convert(returnValueType); 5305 5306 final int scopePopCount = needsCatch ? ci.exceptionScopePops : 0; 5307 5308 // Declare a try/catch for the conversion. If no scopes need to be popped until the target catch block, just 5309 // jump into it. Otherwise, we'll need to create a scope-popping catch block below. 5310 final Label catchLabel = scopePopCount > 0 ? new Label("") : targetCatchLabel; 5311 if(needsCatch) { 5312 final Label _end_try = new Label(""); 5313 method.label(_end_try); 5314 method._try(_try, _end_try, catchLabel); 5315 } 5316 5317 // Jump to continuation point 5318 method._goto(ci.getTargetLabel()); 5319 5320 // Make a scope-popping exception delegate if needed 5321 if(catchLabel != targetCatchLabel) { 5322 method.lineNumber(0); 5323 assert scopePopCount > 0; 5324 method._catch(catchLabel); 5325 popScopes(scopePopCount); 5326 method.uncheckedGoto(targetCatchLabel); 5327 } 5328 } 5329} 5330