1 /*
2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.nashorn.internal.codegen;
27
28 import static jdk.nashorn.internal.codegen.ClassEmitter.Flag.PRIVATE;
29 import static jdk.nashorn.internal.codegen.ClassEmitter.Flag.STATIC;
30 import static jdk.nashorn.internal.codegen.CompilerConstants.ARGUMENTS;
31 import static jdk.nashorn.internal.codegen.CompilerConstants.CALLEE;
32 import static jdk.nashorn.internal.codegen.CompilerConstants.CREATE_PROGRAM_FUNCTION;
33 import static jdk.nashorn.internal.codegen.CompilerConstants.GET_MAP;
34 import static jdk.nashorn.internal.codegen.CompilerConstants.GET_STRING;
35 import static jdk.nashorn.internal.codegen.CompilerConstants.QUICK_PREFIX;
36 import static jdk.nashorn.internal.codegen.CompilerConstants.REGEX_PREFIX;
37 import static jdk.nashorn.internal.codegen.CompilerConstants.SCOPE;
38 import static jdk.nashorn.internal.codegen.CompilerConstants.SPLIT_PREFIX;
39 import static jdk.nashorn.internal.codegen.CompilerConstants.THIS;
40 import static jdk.nashorn.internal.codegen.CompilerConstants.VARARGS;
41 import static jdk.nashorn.internal.codegen.CompilerConstants.constructorNoLookup;
42 import static jdk.nashorn.internal.codegen.CompilerConstants.interfaceCallNoLookup;
43 import static jdk.nashorn.internal.codegen.CompilerConstants.methodDescriptor;
44 import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup;
45 import static jdk.nashorn.internal.codegen.CompilerConstants.typeDescriptor;
46 import static jdk.nashorn.internal.codegen.CompilerConstants.virtualCallNoLookup;
47 import static jdk.nashorn.internal.codegen.ObjectClassGenerator.OBJECT_FIELDS_ONLY;
48 import static jdk.nashorn.internal.ir.Symbol.HAS_SLOT;
49 import static jdk.nashorn.internal.ir.Symbol.IS_INTERNAL;
50 import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.INVALID_PROGRAM_POINT;
51 import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.isValid;
52 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_APPLY_TO_CALL;
53 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_DECLARE;
54 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_FAST_SCOPE;
55 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_OPTIMISTIC;
56 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_PROGRAM_POINT_SHIFT;
57 import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_SCOPE;
58
59 import java.io.PrintWriter;
60 import java.util.ArrayDeque;
61 import java.util.ArrayList;
62 import java.util.Arrays;
63 import java.util.BitSet;
64 import java.util.Collection;
65 import java.util.Collections;
66 import java.util.Deque;
67 import java.util.EnumSet;
68 import java.util.HashMap;
69 import java.util.HashSet;
70 import java.util.Iterator;
71 import java.util.LinkedList;
72 import java.util.List;
73 import java.util.Map;
74 import java.util.Set;
75 import java.util.TreeMap;
76 import java.util.function.Supplier;
77 import jdk.nashorn.internal.AssertsEnabled;
78 import jdk.nashorn.internal.IntDeque;
79 import jdk.nashorn.internal.codegen.ClassEmitter.Flag;
80 import jdk.nashorn.internal.codegen.CompilerConstants.Call;
81 import jdk.nashorn.internal.codegen.types.ArrayType;
82 import jdk.nashorn.internal.codegen.types.Type;
83 import jdk.nashorn.internal.ir.AccessNode;
84 import jdk.nashorn.internal.ir.BaseNode;
85 import jdk.nashorn.internal.ir.BinaryNode;
86 import jdk.nashorn.internal.ir.Block;
87 import jdk.nashorn.internal.ir.BlockStatement;
88 import jdk.nashorn.internal.ir.BreakNode;
89 import jdk.nashorn.internal.ir.BreakableNode;
90 import jdk.nashorn.internal.ir.CallNode;
91 import jdk.nashorn.internal.ir.CaseNode;
92 import jdk.nashorn.internal.ir.CatchNode;
93 import jdk.nashorn.internal.ir.ContinueNode;
94 import jdk.nashorn.internal.ir.EmptyNode;
95 import jdk.nashorn.internal.ir.Expression;
96 import jdk.nashorn.internal.ir.ExpressionStatement;
97 import jdk.nashorn.internal.ir.ForNode;
98 import jdk.nashorn.internal.ir.FunctionNode;
99 import jdk.nashorn.internal.ir.FunctionNode.CompilationState;
100 import jdk.nashorn.internal.ir.GetSplitState;
101 import jdk.nashorn.internal.ir.IdentNode;
102 import jdk.nashorn.internal.ir.IfNode;
103 import jdk.nashorn.internal.ir.IndexNode;
104 import jdk.nashorn.internal.ir.JoinPredecessorExpression;
105 import jdk.nashorn.internal.ir.JumpStatement;
106 import jdk.nashorn.internal.ir.LabelNode;
107 import jdk.nashorn.internal.ir.LexicalContext;
108 import jdk.nashorn.internal.ir.LexicalContextNode;
109 import jdk.nashorn.internal.ir.LiteralNode;
110 import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode;
111 import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode.ArrayUnit;
112 import jdk.nashorn.internal.ir.LiteralNode.PrimitiveLiteralNode;
113 import jdk.nashorn.internal.ir.LocalVariableConversion;
114 import jdk.nashorn.internal.ir.LoopNode;
115 import jdk.nashorn.internal.ir.Node;
116 import jdk.nashorn.internal.ir.ObjectNode;
117 import jdk.nashorn.internal.ir.Optimistic;
118 import jdk.nashorn.internal.ir.PropertyNode;
119 import jdk.nashorn.internal.ir.ReturnNode;
120 import jdk.nashorn.internal.ir.RuntimeNode;
121 import jdk.nashorn.internal.ir.RuntimeNode.Request;
122 import jdk.nashorn.internal.ir.SetSplitState;
123 import jdk.nashorn.internal.ir.SplitReturn;
124 import jdk.nashorn.internal.ir.Statement;
125 import jdk.nashorn.internal.ir.SwitchNode;
126 import jdk.nashorn.internal.ir.Symbol;
127 import jdk.nashorn.internal.ir.TernaryNode;
128 import jdk.nashorn.internal.ir.ThrowNode;
129 import jdk.nashorn.internal.ir.TryNode;
130 import jdk.nashorn.internal.ir.UnaryNode;
131 import jdk.nashorn.internal.ir.VarNode;
132 import jdk.nashorn.internal.ir.WhileNode;
133 import jdk.nashorn.internal.ir.WithNode;
134 import jdk.nashorn.internal.ir.visitor.NodeOperatorVisitor;
135 import jdk.nashorn.internal.ir.visitor.NodeVisitor;
136 import jdk.nashorn.internal.objects.Global;
137 import jdk.nashorn.internal.objects.ScriptFunctionImpl;
138 import jdk.nashorn.internal.parser.Lexer.RegexToken;
139 import jdk.nashorn.internal.parser.TokenType;
140 import jdk.nashorn.internal.runtime.Context;
141 import jdk.nashorn.internal.runtime.Debug;
142 import jdk.nashorn.internal.runtime.ECMAException;
143 import jdk.nashorn.internal.runtime.JSType;
144 import jdk.nashorn.internal.runtime.OptimisticReturnFilters;
145 import jdk.nashorn.internal.runtime.PropertyMap;
146 import jdk.nashorn.internal.runtime.RecompilableScriptFunctionData;
147 import jdk.nashorn.internal.runtime.RewriteException;
148 import jdk.nashorn.internal.runtime.Scope;
149 import jdk.nashorn.internal.runtime.ScriptEnvironment;
150 import jdk.nashorn.internal.runtime.ScriptFunction;
151 import jdk.nashorn.internal.runtime.ScriptObject;
152 import jdk.nashorn.internal.runtime.ScriptRuntime;
153 import jdk.nashorn.internal.runtime.Source;
154 import jdk.nashorn.internal.runtime.Undefined;
155 import jdk.nashorn.internal.runtime.UnwarrantedOptimismException;
156 import jdk.nashorn.internal.runtime.arrays.ArrayData;
157 import jdk.nashorn.internal.runtime.linker.LinkerCallSite;
158 import jdk.nashorn.internal.runtime.logging.DebugLogger;
159 import jdk.nashorn.internal.runtime.logging.Loggable;
160 import jdk.nashorn.internal.runtime.logging.Logger;
161 import jdk.nashorn.internal.runtime.options.Options;
162
163 /**
164 * This is the lowest tier of the code generator. It takes lowered ASTs emitted
165 * from Lower and emits Java byte code. The byte code emission logic is broken
166 * out into MethodEmitter. MethodEmitter works internally with a type stack, and
167 * keeps track of the contents of the byte code stack. This way we avoid a large
168 * number of special cases on the form
169 * <pre>
170 * if (type == INT) {
171 * visitInsn(ILOAD, slot);
172 * } else if (type == DOUBLE) {
173 * visitInsn(DOUBLE, slot);
174 * }
175 * </pre>
176 * This quickly became apparent when the code generator was generalized to work
177 * with all types, and not just numbers or objects.
178 * <p>
179 * The CodeGenerator visits nodes only once, tags them as resolved and emits
180 * bytecode for them.
181 */
182 @Logger(name="codegen")
183 final class CodeGenerator extends NodeOperatorVisitor<CodeGeneratorLexicalContext> implements Loggable {
184
185 private static final Type SCOPE_TYPE = Type.typeFor(ScriptObject.class);
186
187 private static final String GLOBAL_OBJECT = Type.getInternalName(Global.class);
188
189 private static final String SCRIPTFUNCTION_IMPL_NAME = Type.getInternalName(ScriptFunctionImpl.class);
190 private static final Type SCRIPTFUNCTION_IMPL_TYPE = Type.typeFor(ScriptFunction.class);
191
192 private static final Call CREATE_REWRITE_EXCEPTION = CompilerConstants.staticCallNoLookup(RewriteException.class,
193 "create", RewriteException.class, UnwarrantedOptimismException.class, Object[].class, String[].class);
194 private static final Call CREATE_REWRITE_EXCEPTION_REST_OF = CompilerConstants.staticCallNoLookup(RewriteException.class,
195 "create", RewriteException.class, UnwarrantedOptimismException.class, Object[].class, String[].class, int[].class);
196
197 private static final Call ENSURE_INT = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class,
198 "ensureInt", int.class, Object.class, int.class);
199 private static final Call ENSURE_LONG = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class,
200 "ensureLong", long.class, Object.class, int.class);
201 private static final Call ENSURE_NUMBER = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class,
202 "ensureNumber", double.class, Object.class, int.class);
203
204 private static final Class<?> ITERATOR_CLASS = Iterator.class;
205 static {
206 assert ITERATOR_CLASS == CompilerConstants.ITERATOR_PREFIX.type();
207 }
208 private static final Type ITERATOR_TYPE = Type.typeFor(ITERATOR_CLASS);
209 private static final Type EXCEPTION_TYPE = Type.typeFor(CompilerConstants.EXCEPTION_PREFIX.type());
210
211 private static final Integer INT_ZERO = Integer.valueOf(0);
212
213 /** Constant data & installation. The only reason the compiler keeps this is because it is assigned
214 * by reflection in class installation */
215 private final Compiler compiler;
216
217 /** Is the current code submitted by 'eval' call? */
218 private final boolean evalCode;
219
220 /** Call site flags given to the code generator to be used for all generated call sites */
221 private final int callSiteFlags;
222
223 /** How many regexp fields have been emitted */
224 private int regexFieldCount;
225
226 /** Line number for last statement. If we encounter a new line number, line number bytecode information
227 * needs to be generated */
228 private int lastLineNumber = -1;
229
230 /** When should we stop caching regexp expressions in fields to limit bytecode size? */
231 private static final int MAX_REGEX_FIELDS = 2 * 1024;
232
233 /** Current method emitter */
234 private MethodEmitter method;
235
236 /** Current compile unit */
237 private CompileUnit unit;
238
239 private final DebugLogger log;
240
241 /** From what size should we use spill instead of fields for JavaScript objects? */
242 private static final int OBJECT_SPILL_THRESHOLD = Options.getIntProperty("nashorn.spill.threshold", 256);
243
244 private final Set<String> emittedMethods = new HashSet<>();
245
246 // Function Id -> ContinuationInfo. Used by compilation of rest-of function only.
247 private final Map<Integer, ContinuationInfo> fnIdToContinuationInfo = new HashMap<>();
248
249 private final Deque<Label> scopeEntryLabels = new ArrayDeque<>();
250
251 private static final Label METHOD_BOUNDARY = new Label("");
252 private final Deque<Label> catchLabels = new ArrayDeque<>();
253 // Number of live locals on entry to (and thus also break from) labeled blocks.
254 private final IntDeque labeledBlockBreakLiveLocals = new IntDeque();
255
256 //is this a rest of compilation
257 private final int[] continuationEntryPoints;
258
259 /**
260 * Constructor.
261 *
262 * @param compiler
263 */
264 CodeGenerator(final Compiler compiler, final int[] continuationEntryPoints) {
265 super(new CodeGeneratorLexicalContext());
266 this.compiler = compiler;
267 this.evalCode = compiler.getSource().isEvalCode();
268 this.continuationEntryPoints = continuationEntryPoints;
269 this.callSiteFlags = compiler.getScriptEnvironment()._callsite_flags;
270 this.log = initLogger(compiler.getContext());
271 }
272
273 @Override
274 public DebugLogger getLogger() {
275 return log;
276 }
277
278 @Override
279 public DebugLogger initLogger(final Context context) {
280 return context.getLogger(this.getClass());
281 }
282
283 /**
284 * Gets the call site flags, adding the strict flag if the current function
285 * being generated is in strict mode
286 *
287 * @return the correct flags for a call site in the current function
288 */
289 int getCallSiteFlags() {
290 return lc.getCurrentFunction().getCallSiteFlags() | callSiteFlags;
291 }
292
293 /**
294 * Are we generating code for 'eval' code?
295 * @return true if currently compiled code is 'eval' code.
296 */
297 boolean isEvalCode() {
298 return evalCode;
299 }
300
301 /**
302 * Load an identity node
303 *
304 * @param identNode an identity node to load
305 * @return the method generator used
306 */
307 private MethodEmitter loadIdent(final IdentNode identNode, final TypeBounds resultBounds) {
308 checkTemporalDeadZone(identNode);
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 // Any access to LET and CONST variables before their declaration must throw ReferenceError.
342 // This is called the temporal dead zone (TDZ). See https://gist.github.com/rwaldron/f0807a758aa03bcdd58a
343 private void checkTemporalDeadZone(final IdentNode identNode) {
344 if (identNode.isDead()) {
345 method.load(identNode.getSymbol().getName());
346 method.invoke(ScriptRuntime.THROW_REFERENCE_ERROR);
347 }
348 }
349
350 private boolean isRestOf() {
351 return continuationEntryPoints != null;
352 }
353
354 private boolean isOptimisticOrRestOf() {
355 return useOptimisticTypes() || isRestOf();
356 }
357
358 private boolean isCurrentContinuationEntryPoint(final int programPoint) {
359 return isRestOf() && getCurrentContinuationEntryPoint() == programPoint;
360 }
361
362 private int[] getContinuationEntryPoints() {
363 return isRestOf() ? continuationEntryPoints : null;
364 }
365
366 private int getCurrentContinuationEntryPoint() {
367 return isRestOf() ? continuationEntryPoints[0] : INVALID_PROGRAM_POINT;
368 }
369
370 private boolean isContinuationEntryPoint(final int programPoint) {
371 if (isRestOf()) {
372 assert continuationEntryPoints != null;
373 for (final int cep : continuationEntryPoints) {
374 if (cep == programPoint) {
375 return true;
376 }
377 }
378 }
379 return false;
380 }
381
382 /**
383 * Check if this symbol can be accessed directly with a putfield or getfield or dynamic load
384 *
385 * @param symbol symbol to check for fast scope
386 * @return true if fast scope
387 */
388 private boolean isFastScope(final Symbol symbol) {
389 if (!symbol.isScope()) {
390 return false;
391 }
392
393 if (!lc.inDynamicScope()) {
394 // If there's no with or eval in context, and the symbol is marked as scoped, it is fast scoped. Such a
395 // symbol must either be global, or its defining block must need scope.
396 assert symbol.isGlobal() || lc.getDefiningBlock(symbol).needsScope() : symbol.getName();
397 return true;
398 }
399
400 if (symbol.isGlobal()) {
401 // Shortcut: if there's a with or eval in context, globals can't be fast scoped
402 return false;
403 }
404
405 // Otherwise, check if there's a dynamic scope between use of the symbol and its definition
406 final String name = symbol.getName();
407 boolean previousWasBlock = false;
408 for (final Iterator<LexicalContextNode> it = lc.getAllNodes(); it.hasNext();) {
409 final LexicalContextNode node = it.next();
410 if (node instanceof Block) {
411 // If this block defines the symbol, then we can fast scope the symbol.
412 final Block block = (Block)node;
413 if (block.getExistingSymbol(name) == symbol) {
414 assert block.needsScope();
415 return true;
416 }
417 previousWasBlock = true;
418 } else {
419 if (node instanceof WithNode && previousWasBlock || node instanceof FunctionNode && ((FunctionNode)node).needsDynamicScope()) {
420 // If we hit a scope that can have symbols introduced into it at run time before finding the defining
421 // block, the symbol can't be fast scoped. A WithNode only counts if we've immediately seen a block
422 // before - its block. Otherwise, we are currently processing the WithNode's expression, and that's
423 // obviously not subjected to introducing new symbols.
424 return false;
425 }
426 previousWasBlock = false;
427 }
428 }
429 // Should've found the symbol defined in a block
430 throw new AssertionError();
431 }
432
433 private MethodEmitter loadSharedScopeVar(final Type valueType, final Symbol symbol, final int flags) {
434 assert !isOptimisticOrRestOf();
435 if (isFastScope(symbol)) {
436 method.load(getScopeProtoDepth(lc.getCurrentBlock(), symbol));
437 } else {
438 method.load(-1);
439 }
440 return lc.getScopeGet(unit, symbol, valueType, flags | CALLSITE_FAST_SCOPE).generateInvoke(method);
441 }
442
443 private class LoadScopeVar extends OptimisticOperation {
444 final IdentNode identNode;
445 private final int flags;
446
447 LoadScopeVar(final IdentNode identNode, final TypeBounds resultBounds, final int flags) {
448 super(identNode, resultBounds);
449 this.identNode = identNode;
450 this.flags = flags;
451 }
452
453 @Override
454 void loadStack() {
455 method.loadCompilerConstant(SCOPE);
456 getProto();
457 }
458
459 void getProto() {
460 //empty
461 }
462
463 @Override
464 void consumeStack() {
465 // If this is either __FILE__, __DIR__, or __LINE__ then load the property initially as Object as we'd convert
466 // it anyway for replaceLocationPropertyPlaceholder.
467 if(identNode.isCompileTimePropertyName()) {
468 method.dynamicGet(Type.OBJECT, identNode.getSymbol().getName(), flags, identNode.isFunction(), false);
469 replaceCompileTimeProperty();
470 } else {
471 dynamicGet(identNode.getSymbol().getName(), flags, identNode.isFunction(), false);
472 }
473 }
474 }
475
476 private class LoadFastScopeVar extends LoadScopeVar {
477 LoadFastScopeVar(final IdentNode identNode, final TypeBounds resultBounds, final int flags) {
478 super(identNode, resultBounds, flags | CALLSITE_FAST_SCOPE);
479 }
480
481 @Override
482 void getProto() {
483 loadFastScopeProto(identNode.getSymbol(), false);
484 }
485 }
486
487 private MethodEmitter storeFastScopeVar(final Symbol symbol, final int flags) {
488 loadFastScopeProto(symbol, true);
489 method.dynamicSet(symbol.getName(), flags | CALLSITE_FAST_SCOPE, false);
490 return method;
491 }
492
493 private int getScopeProtoDepth(final Block startingBlock, final Symbol symbol) {
494 //walk up the chain from starting block and when we bump into the current function boundary, add the external
495 //information.
496 final FunctionNode fn = lc.getCurrentFunction();
497 final int externalDepth = compiler.getScriptFunctionData(fn.getId()).getExternalSymbolDepth(symbol.getName());
498
499 //count the number of scopes from this place to the start of the function
500
501 final int internalDepth = FindScopeDepths.findInternalDepth(lc, fn, startingBlock, symbol);
502 final int scopesToStart = FindScopeDepths.findScopesToStart(lc, fn, startingBlock);
503 int depth = 0;
504 if (internalDepth == -1) {
505 depth = scopesToStart + externalDepth;
506 } else {
507 assert internalDepth <= scopesToStart;
508 depth = internalDepth;
509 }
510
511 return depth;
512 }
513
514 private void loadFastScopeProto(final Symbol symbol, final boolean swap) {
515 final int depth = getScopeProtoDepth(lc.getCurrentBlock(), symbol);
516 assert depth != -1 : "Couldn't find scope depth for symbol " + symbol.getName() + " in " + lc.getCurrentFunction();
517 if (depth > 0) {
518 if (swap) {
519 method.swap();
520 }
521 for (int i = 0; i < depth; i++) {
522 method.invoke(ScriptObject.GET_PROTO);
523 }
524 if (swap) {
525 method.swap();
526 }
527 }
528 }
529
530 /**
531 * Generate code that loads this node to the stack, not constraining its type
532 *
533 * @param expr node to load
534 *
535 * @return the method emitter used
536 */
537 private MethodEmitter loadExpressionUnbounded(final Expression expr) {
538 return loadExpression(expr, TypeBounds.UNBOUNDED);
539 }
540
541 private MethodEmitter loadExpressionAsObject(final Expression expr) {
542 return loadExpression(expr, TypeBounds.OBJECT);
543 }
544
545 MethodEmitter loadExpressionAsBoolean(final Expression expr) {
546 return loadExpression(expr, TypeBounds.BOOLEAN);
547 }
548
549 // Test whether conversion from source to target involves a call of ES 9.1 ToPrimitive
550 // with possible side effects from calling an object's toString or valueOf methods.
551 private static boolean noToPrimitiveConversion(final Type source, final Type target) {
552 // Object to boolean conversion does not cause ToPrimitive call
553 return source.isJSPrimitive() || !target.isJSPrimitive() || target.isBoolean();
554 }
555
556 MethodEmitter loadBinaryOperands(final BinaryNode binaryNode) {
557 return loadBinaryOperands(binaryNode.lhs(), binaryNode.rhs(), TypeBounds.UNBOUNDED.notWiderThan(binaryNode.getWidestOperandType()), false, false);
558 }
559
560 private MethodEmitter loadBinaryOperands(final Expression lhs, final Expression rhs, final TypeBounds explicitOperandBounds, final boolean baseAlreadyOnStack, final boolean forceConversionSeparation) {
561 // ECMAScript 5.1 specification (sections 11.5-11.11 and 11.13) prescribes that when evaluating a binary
562 // expression "LEFT op RIGHT", the order of operations must be: LOAD LEFT, LOAD RIGHT, CONVERT LEFT, CONVERT
563 // RIGHT, EXECUTE OP. Unfortunately, doing it in this order defeats potential optimizations that arise when we
564 // can combine a LOAD with a CONVERT operation (e.g. use a dynamic getter with the conversion target type as its
565 // return value). What we do here is reorder LOAD RIGHT and CONVERT LEFT when possible; it is possible only when
566 // we can prove that executing CONVERT LEFT can't have a side effect that changes the value of LOAD RIGHT.
567 // Basically, if we know that either LEFT already is a primitive value, or does not have to be converted to
568 // a primitive value, or RIGHT is an expression that loads without side effects, then we can do the
569 // reordering and collapse LOAD/CONVERT into a single operation; otherwise we need to do the more costly
570 // separate operations to preserve specification semantics.
571
572 // Operands' load type should not be narrower than the narrowest of the individual operand types, nor narrower
573 // than the lower explicit bound, but it should also not be wider than
574 final Type lhsType = undefinedToNumber(lhs.getType());
575 final Type rhsType = undefinedToNumber(rhs.getType());
576 final Type narrowestOperandType = Type.narrowest(Type.widest(lhsType, rhsType), explicitOperandBounds.widest);
577 final TypeBounds operandBounds = explicitOperandBounds.notNarrowerThan(narrowestOperandType);
578 if (noToPrimitiveConversion(lhsType, explicitOperandBounds.widest) || rhs.isLocal()) {
579 // Can reorder. We might still need to separate conversion, but at least we can do it with reordering
580 if (forceConversionSeparation) {
581 // Can reorder, but can't move conversion into the operand as the operation depends on operands
582 // exact types for its overflow guarantees. E.g. with {L}{%I}expr1 {L}* {L}{%I}expr2 we are not allowed
583 // to merge {L}{%I} into {%L}, as that can cause subsequent overflows; test for JDK-8058610 contains
584 // concrete cases where this could happen.
585 final TypeBounds safeConvertBounds = TypeBounds.UNBOUNDED.notNarrowerThan(narrowestOperandType);
586 loadExpression(lhs, safeConvertBounds, baseAlreadyOnStack);
587 method.convert(operandBounds.within(method.peekType()));
588 loadExpression(rhs, safeConvertBounds, false);
589 method.convert(operandBounds.within(method.peekType()));
590 } else {
591 // Can reorder and move conversion into the operand. Combine load and convert into single operations.
592 loadExpression(lhs, operandBounds, baseAlreadyOnStack);
593 loadExpression(rhs, operandBounds, false);
594 }
595 } else {
596 // Can't reorder. Load and convert separately.
597 final TypeBounds safeConvertBounds = TypeBounds.UNBOUNDED.notNarrowerThan(narrowestOperandType);
598 loadExpression(lhs, safeConvertBounds, baseAlreadyOnStack);
599 final Type lhsLoadedType = method.peekType();
600 loadExpression(rhs, safeConvertBounds, false);
601 final Type convertedLhsType = operandBounds.within(method.peekType());
602 if (convertedLhsType != lhsLoadedType) {
603 // Do it conditionally, so that if conversion is a no-op we don't introduce a SWAP, SWAP.
604 method.swap().convert(convertedLhsType).swap();
605 }
606 method.convert(operandBounds.within(method.peekType()));
607 }
608 assert Type.generic(method.peekType()) == operandBounds.narrowest;
609 assert Type.generic(method.peekType(1)) == operandBounds.narrowest;
610
611 return method;
612 }
613
614 private static final Type undefinedToNumber(final Type type) {
615 return type == Type.UNDEFINED ? Type.NUMBER : type;
616 }
617
618 private static final class TypeBounds {
619 final Type narrowest;
620 final Type widest;
621
622 static final TypeBounds UNBOUNDED = new TypeBounds(Type.UNKNOWN, Type.OBJECT);
623 static final TypeBounds INT = exact(Type.INT);
624 static final TypeBounds OBJECT = exact(Type.OBJECT);
625 static final TypeBounds BOOLEAN = exact(Type.BOOLEAN);
626
627 static TypeBounds exact(final Type type) {
628 return new TypeBounds(type, type);
629 }
630
631 TypeBounds(final Type narrowest, final Type widest) {
632 assert widest != null && widest != Type.UNDEFINED && widest != Type.UNKNOWN : widest;
633 assert narrowest != null && narrowest != Type.UNDEFINED : narrowest;
634 assert !narrowest.widerThan(widest) : narrowest + " wider than " + widest;
635 assert !widest.narrowerThan(narrowest);
636 this.narrowest = Type.generic(narrowest);
637 this.widest = Type.generic(widest);
638 }
639
640 TypeBounds notNarrowerThan(final Type type) {
641 return maybeNew(Type.narrowest(Type.widest(narrowest, type), widest), widest);
642 }
643
644 TypeBounds notWiderThan(final Type type) {
645 return maybeNew(Type.narrowest(narrowest, type), Type.narrowest(widest, type));
646 }
647
648 boolean canBeNarrowerThan(final Type type) {
649 return narrowest.narrowerThan(type);
650 }
651
652 TypeBounds maybeNew(final Type newNarrowest, final Type newWidest) {
653 if(newNarrowest == narrowest && newWidest == widest) {
654 return this;
655 }
656 return new TypeBounds(newNarrowest, newWidest);
657 }
658
659 TypeBounds booleanToInt() {
660 return maybeNew(CodeGenerator.booleanToInt(narrowest), CodeGenerator.booleanToInt(widest));
661 }
662
663 TypeBounds objectToNumber() {
664 return maybeNew(CodeGenerator.objectToNumber(narrowest), CodeGenerator.objectToNumber(widest));
665 }
666
667 Type within(final Type type) {
668 if(type.narrowerThan(narrowest)) {
669 return narrowest;
670 }
671 if(type.widerThan(widest)) {
672 return widest;
673 }
674 return type;
675 }
676
677 @Override
678 public String toString() {
679 return "[" + narrowest + ", " + widest + "]";
680 }
681 }
682
683 private static Type booleanToInt(final Type t) {
684 return t == Type.BOOLEAN ? Type.INT : t;
685 }
686
687 private static Type objectToNumber(final Type t) {
688 return t.isObject() ? Type.NUMBER : t;
689 }
690
691 MethodEmitter loadExpressionAsType(final Expression expr, final Type type) {
692 if(type == Type.BOOLEAN) {
693 return loadExpressionAsBoolean(expr);
694 } else if(type == Type.UNDEFINED) {
695 assert expr.getType() == Type.UNDEFINED;
696 return loadExpressionAsObject(expr);
697 }
698 // having no upper bound preserves semantics of optimistic operations in the expression (by not having them
699 // converted early) and then applies explicit conversion afterwards.
700 return loadExpression(expr, TypeBounds.UNBOUNDED.notNarrowerThan(type)).convert(type);
701 }
702
703 private MethodEmitter loadExpression(final Expression expr, final TypeBounds resultBounds) {
704 return loadExpression(expr, resultBounds, false);
705 }
706
707 /**
708 * Emits code for evaluating an expression and leaving its value on top of the stack, narrowing or widening it if
709 * necessary.
710 * @param expr the expression to load
711 * @param resultBounds the incoming type bounds. The value on the top of the stack is guaranteed to not be of narrower
712 * type than the narrowest bound, or wider type than the widest bound after it is loaded.
713 * @param baseAlreadyOnStack true if the base of an access or index node is already on the stack. Used to avoid
714 * double evaluation of bases in self-assignment expressions to access and index nodes. {@code Type.OBJECT} is used
715 * to indicate the widest possible type.
716 * @return the method emitter
717 */
718 private MethodEmitter loadExpression(final Expression expr, final TypeBounds resultBounds, final boolean baseAlreadyOnStack) {
719
720 /*
721 * The load may be of type IdentNode, e.g. "x", AccessNode, e.g. "x.y"
722 * or IndexNode e.g. "x[y]". Both AccessNodes and IndexNodes are
723 * BaseNodes and the logic for loading the base object is reused
724 */
725 final CodeGenerator codegen = this;
726
727 final Node currentDiscard = codegen.lc.getCurrentDiscard();
728 expr.accept(new NodeOperatorVisitor<LexicalContext>(new LexicalContext()) {
729 @Override
730 public boolean enterIdentNode(final IdentNode identNode) {
731 loadIdent(identNode, resultBounds);
732 return false;
733 }
734
735 @Override
736 public boolean enterAccessNode(final AccessNode accessNode) {
737 new OptimisticOperation(accessNode, resultBounds) {
738 @Override
739 void loadStack() {
740 if (!baseAlreadyOnStack) {
741 loadExpressionAsObject(accessNode.getBase());
742 }
743 assert method.peekType().isObject();
744 }
745 @Override
746 void consumeStack() {
747 final int flags = getCallSiteFlags();
748 dynamicGet(accessNode.getProperty(), flags, accessNode.isFunction(), accessNode.isIndex());
749 }
750 }.emit(baseAlreadyOnStack ? 1 : 0);
751 return false;
752 }
753
754 @Override
755 public boolean enterIndexNode(final IndexNode indexNode) {
756 new OptimisticOperation(indexNode, resultBounds) {
757 @Override
758 void loadStack() {
759 if (!baseAlreadyOnStack) {
760 loadExpressionAsObject(indexNode.getBase());
761 loadExpressionUnbounded(indexNode.getIndex());
762 }
763 }
764 @Override
765 void consumeStack() {
766 final int flags = getCallSiteFlags();
767 dynamicGetIndex(flags, indexNode.isFunction());
768 }
769 }.emit(baseAlreadyOnStack ? 2 : 0);
770 return false;
771 }
772
773 @Override
774 public boolean enterFunctionNode(final FunctionNode functionNode) {
775 // function nodes will always leave a constructed function object on stack, no need to load the symbol
776 // separately as in enterDefault()
777 lc.pop(functionNode);
778 functionNode.accept(codegen);
779 // NOTE: functionNode.accept() will produce a different FunctionNode that we discard. This incidentally
780 // doesn't cause problems as we're never touching FunctionNode again after it's visited here - codegen
781 // is the last element in the compilation pipeline, the AST it produces is not used externally. So, we
782 // re-push the original functionNode.
783 lc.push(functionNode);
784 return false;
785 }
786
787 @Override
788 public boolean enterASSIGN(final BinaryNode binaryNode) {
789 loadASSIGN(binaryNode);
790 return false;
791 }
792
793 @Override
794 public boolean enterASSIGN_ADD(final BinaryNode binaryNode) {
795 loadASSIGN_ADD(binaryNode);
796 return false;
797 }
798
799 @Override
800 public boolean enterASSIGN_BIT_AND(final BinaryNode binaryNode) {
801 loadASSIGN_BIT_AND(binaryNode);
802 return false;
803 }
804
805 @Override
806 public boolean enterASSIGN_BIT_OR(final BinaryNode binaryNode) {
807 loadASSIGN_BIT_OR(binaryNode);
808 return false;
809 }
810
811 @Override
812 public boolean enterASSIGN_BIT_XOR(final BinaryNode binaryNode) {
813 loadASSIGN_BIT_XOR(binaryNode);
814 return false;
815 }
816
817 @Override
818 public boolean enterASSIGN_DIV(final BinaryNode binaryNode) {
819 loadASSIGN_DIV(binaryNode);
820 return false;
821 }
822
823 @Override
824 public boolean enterASSIGN_MOD(final BinaryNode binaryNode) {
825 loadASSIGN_MOD(binaryNode);
826 return false;
827 }
828
829 @Override
830 public boolean enterASSIGN_MUL(final BinaryNode binaryNode) {
831 loadASSIGN_MUL(binaryNode);
832 return false;
833 }
834
835 @Override
836 public boolean enterASSIGN_SAR(final BinaryNode binaryNode) {
837 loadASSIGN_SAR(binaryNode);
838 return false;
839 }
840
841 @Override
842 public boolean enterASSIGN_SHL(final BinaryNode binaryNode) {
843 loadASSIGN_SHL(binaryNode);
844 return false;
845 }
846
847 @Override
848 public boolean enterASSIGN_SHR(final BinaryNode binaryNode) {
849 loadASSIGN_SHR(binaryNode);
850 return false;
851 }
852
853 @Override
854 public boolean enterASSIGN_SUB(final BinaryNode binaryNode) {
855 loadASSIGN_SUB(binaryNode);
856 return false;
857 }
858
859 @Override
860 public boolean enterCallNode(final CallNode callNode) {
861 return loadCallNode(callNode, resultBounds);
862 }
863
864 @Override
865 public boolean enterLiteralNode(final LiteralNode<?> literalNode) {
866 loadLiteral(literalNode, resultBounds);
867 return false;
868 }
869
870 @Override
871 public boolean enterTernaryNode(final TernaryNode ternaryNode) {
872 loadTernaryNode(ternaryNode, resultBounds);
873 return false;
874 }
875
876 @Override
877 public boolean enterADD(final BinaryNode binaryNode) {
878 loadADD(binaryNode, resultBounds);
879 return false;
880 }
881
882 @Override
883 public boolean enterSUB(final UnaryNode unaryNode) {
884 loadSUB(unaryNode, resultBounds);
885 return false;
886 }
887
888 @Override
889 public boolean enterSUB(final BinaryNode binaryNode) {
890 loadSUB(binaryNode, resultBounds);
891 return false;
892 }
893
894 @Override
895 public boolean enterMUL(final BinaryNode binaryNode) {
896 loadMUL(binaryNode, resultBounds);
897 return false;
898 }
899
900 @Override
901 public boolean enterDIV(final BinaryNode binaryNode) {
902 loadDIV(binaryNode, resultBounds);
903 return false;
904 }
905
906 @Override
907 public boolean enterMOD(final BinaryNode binaryNode) {
908 loadMOD(binaryNode, resultBounds);
909 return false;
910 }
911
912 @Override
913 public boolean enterSAR(final BinaryNode binaryNode) {
914 loadSAR(binaryNode);
915 return false;
916 }
917
918 @Override
919 public boolean enterSHL(final BinaryNode binaryNode) {
920 loadSHL(binaryNode);
921 return false;
922 }
923
924 @Override
925 public boolean enterSHR(final BinaryNode binaryNode) {
926 loadSHR(binaryNode);
927 return false;
928 }
929
930 @Override
931 public boolean enterCOMMALEFT(final BinaryNode binaryNode) {
932 loadCOMMALEFT(binaryNode, resultBounds);
933 return false;
934 }
935
936 @Override
937 public boolean enterCOMMARIGHT(final BinaryNode binaryNode) {
938 loadCOMMARIGHT(binaryNode, resultBounds);
939 return false;
940 }
941
942 @Override
943 public boolean enterAND(final BinaryNode binaryNode) {
944 loadAND_OR(binaryNode, resultBounds, true);
945 return false;
946 }
947
948 @Override
949 public boolean enterOR(final BinaryNode binaryNode) {
950 loadAND_OR(binaryNode, resultBounds, false);
951 return false;
952 }
953
954 @Override
955 public boolean enterNOT(final UnaryNode unaryNode) {
956 loadNOT(unaryNode);
957 return false;
958 }
959
960 @Override
961 public boolean enterADD(final UnaryNode unaryNode) {
962 loadADD(unaryNode, resultBounds);
963 return false;
964 }
965
966 @Override
967 public boolean enterBIT_NOT(final UnaryNode unaryNode) {
968 loadBIT_NOT(unaryNode);
969 return false;
970 }
971
972 @Override
973 public boolean enterBIT_AND(final BinaryNode binaryNode) {
974 loadBIT_AND(binaryNode);
975 return false;
976 }
977
978 @Override
979 public boolean enterBIT_OR(final BinaryNode binaryNode) {
980 loadBIT_OR(binaryNode);
981 return false;
982 }
983
984 @Override
985 public boolean enterBIT_XOR(final BinaryNode binaryNode) {
986 loadBIT_XOR(binaryNode);
987 return false;
988 }
989
990 @Override
991 public boolean enterVOID(final UnaryNode unaryNode) {
992 loadVOID(unaryNode, resultBounds);
993 return false;
994 }
995
996 @Override
997 public boolean enterEQ(final BinaryNode binaryNode) {
998 loadCmp(binaryNode, Condition.EQ);
999 return false;
1000 }
1001
1002 @Override
1003 public boolean enterEQ_STRICT(final BinaryNode binaryNode) {
1004 loadCmp(binaryNode, Condition.EQ);
1005 return false;
1006 }
1007
1008 @Override
1009 public boolean enterGE(final BinaryNode binaryNode) {
1010 loadCmp(binaryNode, Condition.GE);
1011 return false;
1012 }
1013
1014 @Override
1015 public boolean enterGT(final BinaryNode binaryNode) {
1016 loadCmp(binaryNode, Condition.GT);
1017 return false;
1018 }
1019
1020 @Override
1021 public boolean enterLE(final BinaryNode binaryNode) {
1022 loadCmp(binaryNode, Condition.LE);
1023 return false;
1024 }
1025
1026 @Override
1027 public boolean enterLT(final BinaryNode binaryNode) {
1028 loadCmp(binaryNode, Condition.LT);
1029 return false;
1030 }
1031
1032 @Override
1033 public boolean enterNE(final BinaryNode binaryNode) {
1034 loadCmp(binaryNode, Condition.NE);
1035 return false;
1036 }
1037
1038 @Override
1039 public boolean enterNE_STRICT(final BinaryNode binaryNode) {
1040 loadCmp(binaryNode, Condition.NE);
1041 return false;
1042 }
1043
1044 @Override
1045 public boolean enterObjectNode(final ObjectNode objectNode) {
1046 loadObjectNode(objectNode);
1047 return false;
1048 }
1049
1050 @Override
1051 public boolean enterRuntimeNode(final RuntimeNode runtimeNode) {
1052 loadRuntimeNode(runtimeNode);
1053 return false;
1054 }
1055
1056 @Override
1057 public boolean enterNEW(final UnaryNode unaryNode) {
1058 loadNEW(unaryNode);
1059 return false;
1060 }
1061
1062 @Override
1063 public boolean enterDECINC(final UnaryNode unaryNode) {
1064 loadDECINC(unaryNode);
1065 return false;
1066 }
1067
1068 @Override
1069 public boolean enterJoinPredecessorExpression(final JoinPredecessorExpression joinExpr) {
1070 loadExpression(joinExpr.getExpression(), resultBounds);
1071 return false;
1072 }
1073
1074 @Override
1075 public boolean enterGetSplitState(final GetSplitState getSplitState) {
1076 method.loadScope();
1077 method.invoke(Scope.GET_SPLIT_STATE);
1078 return false;
1079 }
1080
1081 @Override
1082 public boolean enterDefault(final Node otherNode) {
1083 // Must have handled all expressions that can legally be encountered.
1084 throw new AssertionError(otherNode.getClass().getName());
1085 }
1086 });
1087 if(currentDiscard != expr) {
1088 coerceStackTop(resultBounds);
1089 }
1090 return method;
1091 }
1092
1093 private MethodEmitter coerceStackTop(final TypeBounds typeBounds) {
1094 return method.convert(typeBounds.within(method.peekType()));
1095 }
1096
1097 /**
1098 * Closes any still open entries for this block's local variables in the bytecode local variable table.
1099 *
1100 * @param block block containing symbols.
1101 */
1102 private void closeBlockVariables(final Block block) {
1103 for (final Symbol symbol : block.getSymbols()) {
1104 if (symbol.isBytecodeLocal()) {
1105 method.closeLocalVariable(symbol, block.getBreakLabel());
1106 }
1107 }
1108 }
1109
1110 @Override
1111 public boolean enterBlock(final Block block) {
1112 method.label(block.getEntryLabel());
1113 if(!method.isReachable()) {
1114 return false;
1115 }
1116 if(lc.isFunctionBody() && emittedMethods.contains(lc.getCurrentFunction().getName())) {
1117 return false;
1118 }
1119 initLocals(block);
1120
1121 assert lc.getUsedSlotCount() == method.getFirstTemp();
1122 return true;
1123 }
1124
1125 private boolean useOptimisticTypes() {
1126 return !lc.inSplitNode() && compiler.useOptimisticTypes();
1127 }
1128
1129 @Override
1130 public Node leaveBlock(final Block block) {
1131 popBlockScope(block);
1132 method.beforeJoinPoint(block);
1133
1134 closeBlockVariables(block);
1135 lc.releaseSlots();
1136 assert !method.isReachable() || (lc.isFunctionBody() ? 0 : lc.getUsedSlotCount()) == method.getFirstTemp() :
1137 "reachable="+method.isReachable() +
1138 " isFunctionBody=" + lc.isFunctionBody() +
1139 " usedSlotCount=" + lc.getUsedSlotCount() +
1140 " firstTemp=" + method.getFirstTemp();
1141
1142 return block;
1143 }
1144
1145 private void popBlockScope(final Block block) {
1146 final Label breakLabel = block.getBreakLabel();
1147
1148 if(!block.needsScope() || lc.isFunctionBody()) {
1149 emitBlockBreakLabel(breakLabel);
1150 return;
1151 }
1152
1153 final Label beginTryLabel = scopeEntryLabels.pop();
1154 final Label recoveryLabel = new Label("block_popscope_catch");
1155 emitBlockBreakLabel(breakLabel);
1156 final boolean bodyCanThrow = breakLabel.isAfter(beginTryLabel);
1157 if(bodyCanThrow) {
1158 method._try(beginTryLabel, breakLabel, recoveryLabel);
1159 }
1160
1161 Label afterCatchLabel = null;
1162
1163 if(method.isReachable()) {
1164 popScope();
1165 if(bodyCanThrow) {
1166 afterCatchLabel = new Label("block_after_catch");
1167 method._goto(afterCatchLabel);
1168 }
1169 }
1170
1171 if(bodyCanThrow) {
1172 assert !method.isReachable();
1173 method._catch(recoveryLabel);
1174 popScopeException();
1175 method.athrow();
1176 }
1177 if(afterCatchLabel != null) {
1178 method.label(afterCatchLabel);
1179 }
1180 }
1181
1182 private void emitBlockBreakLabel(final Label breakLabel) {
1183 // TODO: this is totally backwards. Block should not be breakable, LabelNode should be breakable.
1184 final LabelNode labelNode = lc.getCurrentBlockLabelNode();
1185 if(labelNode != null) {
1186 // Only have conversions if we're reachable
1187 assert labelNode.getLocalVariableConversion() == null || method.isReachable();
1188 method.beforeJoinPoint(labelNode);
1189 method.breakLabel(breakLabel, labeledBlockBreakLiveLocals.pop());
1190 } else {
1191 method.label(breakLabel);
1192 }
1193 }
1194
1195 private void popScope() {
1196 popScopes(1);
1197 }
1198
1199 /**
1200 * Pop scope as part of an exception handler. Similar to {@code popScope()} but also takes care of adjusting the
1201 * number of scopes that needs to be popped in case a rest-of continuation handler encounters an exception while
1202 * performing a ToPrimitive conversion.
1203 */
1204 private void popScopeException() {
1205 popScope();
1206 final ContinuationInfo ci = getContinuationInfo();
1207 if(ci != null) {
1208 final Label catchLabel = ci.catchLabel;
1209 if(catchLabel != METHOD_BOUNDARY && catchLabel == catchLabels.peek()) {
1210 ++ci.exceptionScopePops;
1211 }
1212 }
1213 }
1214
1215 private void popScopesUntil(final LexicalContextNode until) {
1216 popScopes(lc.getScopeNestingLevelTo(until));
1217 }
1218
1219 private void popScopes(final int count) {
1220 if(count == 0) {
1221 return;
1222 }
1223 assert count > 0; // together with count == 0 check, asserts nonnegative count
1224 if (!method.hasScope()) {
1225 // We can sometimes invoke this method even if the method has no slot for the scope object. Typical example:
1226 // for(;;) { with({}) { break; } }. WithNode normally creates a scope, but if it uses no identifiers and
1227 // nothing else forces creation of a scope in the method, we just won't have the :scope local variable.
1228 return;
1229 }
1230 method.loadCompilerConstant(SCOPE);
1231 for(int i = 0; i < count; ++i) {
1232 method.invoke(ScriptObject.GET_PROTO);
1233 }
1234 method.storeCompilerConstant(SCOPE);
1235 }
1236
1237 @Override
1238 public boolean enterBreakNode(final BreakNode breakNode) {
1239 return enterJumpStatement(breakNode);
1240 }
1241
1242 private boolean enterJumpStatement(final JumpStatement jump) {
1243 if(!method.isReachable()) {
1244 return false;
1245 }
1246 enterStatement(jump);
1247
1248 method.beforeJoinPoint(jump);
1249 final BreakableNode target = jump.getTarget(lc);
1250 popScopesUntil(target);
1251 final Label targetLabel = jump.getTargetLabel(target);
1252 targetLabel.markAsBreakTarget();
1253 method._goto(targetLabel);
1254
1255 return false;
1256 }
1257
1258 private int loadArgs(final List<Expression> args) {
1259 final int argCount = args.size();
1260 // arg have already been converted to objects here.
1261 if (argCount > LinkerCallSite.ARGLIMIT) {
1262 loadArgsArray(args);
1263 return 1;
1264 }
1265
1266 for (final Expression arg : args) {
1267 assert arg != null;
1268 loadExpressionUnbounded(arg);
1269 }
1270 return argCount;
1271 }
1272
1273 private boolean loadCallNode(final CallNode callNode, final TypeBounds resultBounds) {
1274 lineNumber(callNode.getLineNumber());
1275
1276 final List<Expression> args = callNode.getArgs();
1277 final Expression function = callNode.getFunction();
1278 final Block currentBlock = lc.getCurrentBlock();
1279 final CodeGeneratorLexicalContext codegenLexicalContext = lc;
1280
1281 function.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) {
1282
1283 private MethodEmitter sharedScopeCall(final IdentNode identNode, final int flags) {
1284 final Symbol symbol = identNode.getSymbol();
1285 final boolean isFastScope = isFastScope(symbol);
1286 final int scopeCallFlags = flags | (isFastScope ? CALLSITE_FAST_SCOPE : 0);
1287 new OptimisticOperation(callNode, resultBounds) {
1288 @Override
1289 void loadStack() {
1290 method.loadCompilerConstant(SCOPE);
1291 if (isFastScope) {
1292 method.load(getScopeProtoDepth(currentBlock, symbol));
1293 } else {
1294 method.load(-1); // Bypass fast-scope code in shared callsite
1295 }
1296 loadArgs(args);
1297 }
1298 @Override
1299 void consumeStack() {
1300 final Type[] paramTypes = method.getTypesFromStack(args.size());
1301 // We have trouble finding e.g. in Type.typeFor(asm.Type) because it can't see the Context class
1302 // loader, so we need to weaken reference signatures to Object.
1303 for(int i = 0; i < paramTypes.length; ++i) {
1304 paramTypes[i] = Type.generic(paramTypes[i]);
1305 }
1306 // As shared scope calls are only used in non-optimistic compilation, we switch from using
1307 // TypeBounds to just a single definitive type, resultBounds.widest.
1308 final SharedScopeCall scopeCall = codegenLexicalContext.getScopeCall(unit, symbol,
1309 identNode.getType(), resultBounds.widest, paramTypes, scopeCallFlags);
1310 scopeCall.generateInvoke(method);
1311 }
1312 }.emit();
1313 return method;
1314 }
1315
1316 private void scopeCall(final IdentNode ident, final int flags) {
1317 new OptimisticOperation(callNode, resultBounds) {
1318 int argsCount;
1319 @Override
1320 void loadStack() {
1321 loadExpressionAsObject(ident); // foo() makes no sense if foo == 3
1322 // ScriptFunction will see CALLSITE_SCOPE and will bind scope accordingly.
1323 method.loadUndefined(Type.OBJECT); //the 'this'
1324 argsCount = loadArgs(args);
1325 }
1326 @Override
1327 void consumeStack() {
1328 dynamicCall(2 + argsCount, flags);
1329 }
1330 }.emit();
1331 }
1332
1333 private void evalCall(final IdentNode ident, final int flags) {
1334 final Label invoke_direct_eval = new Label("invoke_direct_eval");
1335 final Label is_not_eval = new Label("is_not_eval");
1336 final Label eval_done = new Label("eval_done");
1337
1338 new OptimisticOperation(callNode, resultBounds) {
1339 int argsCount;
1340 @Override
1341 void loadStack() {
1342 /**
1343 * We want to load 'eval' to check if it is indeed global builtin eval.
1344 * If this eval call is inside a 'with' statement, dyn:getMethod|getProp|getElem
1345 * would be generated if ident is a "isFunction". But, that would result in a
1346 * bound function from WithObject. We don't want that as bound function as that
1347 * won't be detected as builtin eval. So, we make ident as "not a function" which
1348 * results in "dyn:getProp|getElem|getMethod" being generated and so WithObject
1349 * would return unbounded eval function.
1350 *
1351 * Example:
1352 *
1353 * var global = this;
1354 * function func() {
1355 * with({ eval: global.eval) { eval("var x = 10;") }
1356 * }
1357 */
1358 loadExpressionAsObject(ident.setIsNotFunction()); // Type.OBJECT as foo() makes no sense if foo == 3
1359 globalIsEval();
1360 method.ifeq(is_not_eval);
1361
1362 // Load up self (scope).
1363 method.loadCompilerConstant(SCOPE);
1364 final List<Expression> evalArgs = callNode.getEvalArgs().getArgs();
1365 // load evaluated code
1366 loadExpressionAsObject(evalArgs.get(0));
1367 // load second and subsequent args for side-effect
1368 final int numArgs = evalArgs.size();
1369 for (int i = 1; i < numArgs; i++) {
1370 loadAndDiscard(evalArgs.get(i));
1371 }
1372 method._goto(invoke_direct_eval);
1373
1374 method.label(is_not_eval);
1375 // load this time but with dyn:getMethod|getProp|getElem
1376 loadExpressionAsObject(ident); // Type.OBJECT as foo() makes no sense if foo == 3
1377 // This is some scope 'eval' or global eval replaced by user
1378 // but not the built-in ECMAScript 'eval' function call
1379 method.loadNull();
1380 argsCount = loadArgs(callNode.getArgs());
1381 }
1382
1383 @Override
1384 void consumeStack() {
1385 // Ordinary call
1386 dynamicCall(2 + argsCount, flags);
1387 method._goto(eval_done);
1388
1389 method.label(invoke_direct_eval);
1390 // Special/extra 'eval' arguments. These can be loaded late (in consumeStack) as we know none of
1391 // them can ever be optimistic.
1392 method.loadCompilerConstant(THIS);
1393 method.load(callNode.getEvalArgs().getLocation());
1394 method.load(CodeGenerator.this.lc.getCurrentFunction().isStrict());
1395 // direct call to Global.directEval
1396 globalDirectEval();
1397 convertOptimisticReturnValue();
1398 coerceStackTop(resultBounds);
1399 }
1400 }.emit();
1401
1402 method.label(eval_done);
1403 }
1404
1405 @Override
1406 public boolean enterIdentNode(final IdentNode node) {
1407 final Symbol symbol = node.getSymbol();
1408
1409 if (symbol.isScope()) {
1410 final int flags = getCallSiteFlags() | CALLSITE_SCOPE;
1411 final int useCount = symbol.getUseCount();
1412
1413 // Threshold for generating shared scope callsite is lower for fast scope symbols because we know
1414 // we can dial in the correct scope. However, we also need to enable it for non-fast scopes to
1415 // support huge scripts like mandreel.js.
1416 if (callNode.isEval()) {
1417 evalCall(node, flags);
1418 } else if (useCount <= SharedScopeCall.FAST_SCOPE_CALL_THRESHOLD
1419 || !isFastScope(symbol) && useCount <= SharedScopeCall.SLOW_SCOPE_CALL_THRESHOLD
1420 || CodeGenerator.this.lc.inDynamicScope()
1421 || isOptimisticOrRestOf()) {
1422 scopeCall(node, flags);
1423 } else {
1424 sharedScopeCall(node, flags);
1425 }
1426 assert method.peekType().equals(resultBounds.within(callNode.getType())) : method.peekType() + " != " + resultBounds + "(" + callNode.getType() + ")";
1427 } else {
1428 enterDefault(node);
1429 }
1430
1431 return false;
1432 }
1433
1434 @Override
1435 public boolean enterAccessNode(final AccessNode node) {
1436 //check if this is an apply to call node. only real applies, that haven't been
1437 //shadowed from their way to the global scope counts
1438
1439 //call nodes have program points.
1440
1441 final int flags = getCallSiteFlags() | (callNode.isApplyToCall() ? CALLSITE_APPLY_TO_CALL : 0);
1442
1443 new OptimisticOperation(callNode, resultBounds) {
1444 int argCount;
1445 @Override
1446 void loadStack() {
1447 loadExpressionAsObject(node.getBase());
1448 method.dup();
1449 // NOTE: not using a nested OptimisticOperation on this dynamicGet, as we expect to get back
1450 // a callable object. Nobody in their right mind would optimistically type this call site.
1451 assert !node.isOptimistic();
1452 method.dynamicGet(node.getType(), node.getProperty(), flags, true, node.isIndex());
1453 method.swap();
1454 argCount = loadArgs(args);
1455 }
1456 @Override
1457 void consumeStack() {
1458 dynamicCall(2 + argCount, flags);
1459 }
1460 }.emit();
1461
1462 return false;
1463 }
1464
1465 @Override
1466 public boolean enterFunctionNode(final FunctionNode origCallee) {
1467 new OptimisticOperation(callNode, resultBounds) {
1468 FunctionNode callee;
1469 int argsCount;
1470 @Override
1471 void loadStack() {
1472 callee = (FunctionNode)origCallee.accept(CodeGenerator.this);
1473 if (callee.isStrict()) { // "this" is undefined
1474 method.loadUndefined(Type.OBJECT);
1475 } else { // get global from scope (which is the self)
1476 globalInstance();
1477 }
1478 argsCount = loadArgs(args);
1479 }
1480
1481 @Override
1482 void consumeStack() {
1483 final int flags = getCallSiteFlags();
1484 //assert callNodeType.equals(callee.getReturnType()) : callNodeType + " != " + callee.getReturnType();
1485 dynamicCall(2 + argsCount, flags);
1486 }
1487 }.emit();
1488 return false;
1489 }
1490
1491 @Override
1492 public boolean enterIndexNode(final IndexNode node) {
1493 new OptimisticOperation(callNode, resultBounds) {
1494 int argsCount;
1495 @Override
1496 void loadStack() {
1497 loadExpressionAsObject(node.getBase());
1498 method.dup();
1499 final Type indexType = node.getIndex().getType();
1500 if (indexType.isObject() || indexType.isBoolean()) {
1501 loadExpressionAsObject(node.getIndex()); //TODO boolean
1502 } else {
1503 loadExpressionUnbounded(node.getIndex());
1504 }
1505 // NOTE: not using a nested OptimisticOperation on this dynamicGetIndex, as we expect to get
1506 // back a callable object. Nobody in their right mind would optimistically type this call site.
1507 assert !node.isOptimistic();
1508 method.dynamicGetIndex(node.getType(), getCallSiteFlags(), true);
1509 method.swap();
1510 argsCount = loadArgs(args);
1511 }
1512 @Override
1513 void consumeStack() {
1514 final int flags = getCallSiteFlags();
1515 dynamicCall(2 + argsCount, flags);
1516 }
1517 }.emit();
1518 return false;
1519 }
1520
1521 @Override
1522 protected boolean enterDefault(final Node node) {
1523 new OptimisticOperation(callNode, resultBounds) {
1524 int argsCount;
1525 @Override
1526 void loadStack() {
1527 // Load up function.
1528 loadExpressionAsObject(function); //TODO, e.g. booleans can be used as functions
1529 method.loadUndefined(Type.OBJECT); // ScriptFunction will figure out the correct this when it sees CALLSITE_SCOPE
1530 argsCount = loadArgs(args);
1531 }
1532 @Override
1533 void consumeStack() {
1534 final int flags = getCallSiteFlags() | CALLSITE_SCOPE;
1535 dynamicCall(2 + argsCount, flags);
1536 }
1537 }.emit();
1538 return false;
1539 }
1540 });
1541
1542 return false;
1543 }
1544
1545 /**
1546 * Returns the flags with optimistic flag and program point removed.
1547 * @param flags the flags that need optimism stripped from them.
1548 * @return flags without optimism
1549 */
1550 static int nonOptimisticFlags(final int flags) {
1551 return flags & ~(CALLSITE_OPTIMISTIC | -1 << CALLSITE_PROGRAM_POINT_SHIFT);
1552 }
1553
1554 @Override
1555 public boolean enterContinueNode(final ContinueNode continueNode) {
1556 return enterJumpStatement(continueNode);
1557 }
1558
1559 @Override
1560 public boolean enterEmptyNode(final EmptyNode emptyNode) {
1561 if(!method.isReachable()) {
1562 return false;
1563 }
1564 enterStatement(emptyNode);
1565
1566 return false;
1567 }
1568
1569 @Override
1570 public boolean enterExpressionStatement(final ExpressionStatement expressionStatement) {
1571 if(!method.isReachable()) {
1572 return false;
1573 }
1574 enterStatement(expressionStatement);
1575
1576 loadAndDiscard(expressionStatement.getExpression());
1577 assert method.getStackSize() == 0;
1578
1579 return false;
1580 }
1581
1582 @Override
1583 public boolean enterBlockStatement(final BlockStatement blockStatement) {
1584 if(!method.isReachable()) {
1585 return false;
1586 }
1587 enterStatement(blockStatement);
1588
1589 blockStatement.getBlock().accept(this);
1590
1591 return false;
1592 }
1593
1594 @Override
1595 public boolean enterForNode(final ForNode forNode) {
1596 if(!method.isReachable()) {
1597 return false;
1598 }
1599 enterStatement(forNode);
1600 if (forNode.isForIn()) {
1601 enterForIn(forNode);
1602 } else {
1603 final Expression init = forNode.getInit();
1604 if (init != null) {
1605 loadAndDiscard(init);
1606 }
1607 enterForOrWhile(forNode, forNode.getModify());
1608 }
1609
1610 return false;
1611 }
1612
1613 private void enterForIn(final ForNode forNode) {
1614 loadExpression(forNode.getModify(), TypeBounds.OBJECT);
1615 method.invoke(forNode.isForEach() ? ScriptRuntime.TO_VALUE_ITERATOR : ScriptRuntime.TO_PROPERTY_ITERATOR);
1616 final Symbol iterSymbol = forNode.getIterator();
1617 final int iterSlot = iterSymbol.getSlot(Type.OBJECT);
1618 method.store(iterSymbol, ITERATOR_TYPE);
1619
1620 method.beforeJoinPoint(forNode);
1621
1622 final Label continueLabel = forNode.getContinueLabel();
1623 final Label breakLabel = forNode.getBreakLabel();
1624
1625 method.label(continueLabel);
1626 method.load(ITERATOR_TYPE, iterSlot);
1627 method.invoke(interfaceCallNoLookup(ITERATOR_CLASS, "hasNext", boolean.class));
1628 final JoinPredecessorExpression test = forNode.getTest();
1629 final Block body = forNode.getBody();
1630 if(LocalVariableConversion.hasLiveConversion(test)) {
1631 final Label afterConversion = new Label("for_in_after_test_conv");
1632 method.ifne(afterConversion);
1633 method.beforeJoinPoint(test);
1634 method._goto(breakLabel);
1635 method.label(afterConversion);
1636 } else {
1637 method.ifeq(breakLabel);
1638 }
1639
1640 new Store<Expression>(forNode.getInit()) {
1641 @Override
1642 protected void storeNonDiscard() {
1643 // This expression is neither part of a discard, nor needs to be left on the stack after it was
1644 // stored, so we override storeNonDiscard to be a no-op.
1645 }
1646
1647 @Override
1648 protected void evaluate() {
1649 new OptimisticOperation((Optimistic)forNode.getInit(), TypeBounds.UNBOUNDED) {
1650 @Override
1651 void loadStack() {
1652 method.load(ITERATOR_TYPE, iterSlot);
1653 }
1654
1655 @Override
1656 void consumeStack() {
1657 method.invoke(interfaceCallNoLookup(ITERATOR_CLASS, "next", Object.class));
1658 convertOptimisticReturnValue();
1659 }
1660 }.emit();
1661 }
1662 }.store();
1663 body.accept(this);
1664
1665 if(method.isReachable()) {
1666 method._goto(continueLabel);
1667 }
1668 method.label(breakLabel);
1669 }
1670
1671 /**
1672 * Initialize the slots in a frame to undefined.
1673 *
1674 * @param block block with local vars.
1675 */
1676 private void initLocals(final Block block) {
1677 lc.onEnterBlock(block);
1678
1679 final boolean isFunctionBody = lc.isFunctionBody();
1680 final FunctionNode function = lc.getCurrentFunction();
1681 if (isFunctionBody) {
1682 initializeMethodParameters(function);
1683 if(!function.isVarArg()) {
1684 expandParameterSlots(function);
1685 }
1686 if (method.hasScope()) {
1687 if (function.needsParentScope()) {
1688 method.loadCompilerConstant(CALLEE);
1689 method.invoke(ScriptFunction.GET_SCOPE);
1690 } else {
1691 assert function.hasScopeBlock();
1692 method.loadNull();
1693 }
1694 method.storeCompilerConstant(SCOPE);
1695 }
1696 if (function.needsArguments()) {
1697 initArguments(function);
1698 }
1699 }
1700
1701 /*
1702 * Determine if block needs scope, if not, just do initSymbols for this block.
1703 */
1704 if (block.needsScope()) {
1705 /*
1706 * Determine if function is varargs and consequently variables have to
1707 * be in the scope.
1708 */
1709 final boolean varsInScope = function.allVarsInScope();
1710
1711 // TODO for LET we can do better: if *block* does not contain any eval/with, we don't need its vars in scope.
1712
1713 final boolean hasArguments = function.needsArguments();
1714 final List<MapTuple<Symbol>> tuples = new ArrayList<>();
1715 final Iterator<IdentNode> paramIter = function.getParameters().iterator();
1716 for (final Symbol symbol : block.getSymbols()) {
1717 if (symbol.isInternal() || symbol.isThis()) {
1718 continue;
1719 }
1720
1721 if (symbol.isVar()) {
1722 assert !varsInScope || symbol.isScope();
1723 if (varsInScope || symbol.isScope()) {
1724 assert symbol.isScope() : "scope for " + symbol + " should have been set in Lower already " + function.getName();
1725 assert !symbol.hasSlot() : "slot for " + symbol + " should have been removed in Lower already" + function.getName();
1726
1727 //this tuple will not be put fielded, as it has no value, just a symbol
1728 tuples.add(new MapTuple<Symbol>(symbol.getName(), symbol, null));
1729 } else {
1730 assert symbol.hasSlot() || symbol.slotCount() == 0 : symbol + " should have a slot only, no scope";
1731 }
1732 } else if (symbol.isParam() && (varsInScope || hasArguments || symbol.isScope())) {
1733 assert symbol.isScope() : "scope for " + symbol + " should have been set in AssignSymbols already " + function.getName() + " varsInScope="+varsInScope+" hasArguments="+hasArguments+" symbol.isScope()=" + symbol.isScope();
1734 assert !(hasArguments && symbol.hasSlot()) : "slot for " + symbol + " should have been removed in Lower already " + function.getName();
1735
1736 final Type paramType;
1737 final Symbol paramSymbol;
1738
1739 if (hasArguments) {
1740 assert !symbol.hasSlot() : "slot for " + symbol + " should have been removed in Lower already ";
1741 paramSymbol = null;
1742 paramType = null;
1743 } else {
1744 paramSymbol = symbol;
1745 // NOTE: We're relying on the fact here that Block.symbols is a LinkedHashMap, hence it will
1746 // return symbols in the order they were defined, and parameters are defined in the same order
1747 // they appear in the function. That's why we can have a single pass over the parameter list
1748 // with an iterator, always just scanning forward for the next parameter that matches the symbol
1749 // name.
1750 for(;;) {
1751 final IdentNode nextParam = paramIter.next();
1752 if(nextParam.getName().equals(symbol.getName())) {
1753 paramType = nextParam.getType();
1754 break;
1755 }
1756 }
1757 }
1758
1759 tuples.add(new MapTuple<Symbol>(symbol.getName(), symbol, paramType, paramSymbol) {
1760 //this symbol will be put fielded, we can't initialize it as undefined with a known type
1761 @Override
1762 public Class<?> getValueType() {
1763 if (OBJECT_FIELDS_ONLY || value == null || paramType == null) {
1764 return Object.class;
1765 }
1766 return paramType.isBoolean() ? Object.class : paramType.getTypeClass();
1767 }
1768 });
1769 }
1770 }
1771
1772 /*
1773 * Create a new object based on the symbols and values, generate
1774 * bootstrap code for object
1775 */
1776 new FieldObjectCreator<Symbol>(this, tuples, true, hasArguments) {
1777 @Override
1778 protected void loadValue(final Symbol value, final Type type) {
1779 method.load(value, type);
1780 }
1781 }.makeObject(method);
1782 // program function: merge scope into global
1783 if (isFunctionBody && function.isProgram()) {
1784 method.invoke(ScriptRuntime.MERGE_SCOPE);
1785 }
1786
1787 method.storeCompilerConstant(SCOPE);
1788 if(!isFunctionBody) {
1789 // Function body doesn't need a try/catch to restore scope, as it'd be a dead store anyway. Allowing it
1790 // actually causes issues with UnwarrantedOptimismException handlers as ASM will sort this handler to
1791 // the top of the exception handler table, so it'll be triggered instead of the UOE handlers.
1792 final Label scopeEntryLabel = new Label("scope_entry");
1793 scopeEntryLabels.push(scopeEntryLabel);
1794 method.label(scopeEntryLabel);
1795 }
1796 } else if (isFunctionBody && function.isVarArg()) {
1797 // Since we don't have a scope, parameters didn't get assigned array indices by the FieldObjectCreator, so
1798 // we need to assign them separately here.
1799 int nextParam = 0;
1800 for (final IdentNode param : function.getParameters()) {
1801 param.getSymbol().setFieldIndex(nextParam++);
1802 }
1803 }
1804
1805 // Debugging: print symbols? @see --print-symbols flag
1806 printSymbols(block, function, (isFunctionBody ? "Function " : "Block in ") + (function.getIdent() == null ? "<anonymous>" : function.getIdent().getName()));
1807 }
1808
1809 /**
1810 * Incoming method parameters are always declared on method entry; declare them in the local variable table.
1811 * @param function function for which code is being generated.
1812 */
1813 private void initializeMethodParameters(final FunctionNode function) {
1814 final Label functionStart = new Label("fn_start");
1815 method.label(functionStart);
1816 int nextSlot = 0;
1817 if(function.needsCallee()) {
1818 initializeInternalFunctionParameter(CALLEE, function, functionStart, nextSlot++);
1819 }
1820 initializeInternalFunctionParameter(THIS, function, functionStart, nextSlot++);
1821 if(function.isVarArg()) {
1822 initializeInternalFunctionParameter(VARARGS, function, functionStart, nextSlot++);
1823 } else {
1824 for(final IdentNode param: function.getParameters()) {
1825 final Symbol symbol = param.getSymbol();
1826 if(symbol.isBytecodeLocal()) {
1827 method.initializeMethodParameter(symbol, param.getType(), functionStart);
1828 }
1829 }
1830 }
1831 }
1832
1833 private void initializeInternalFunctionParameter(final CompilerConstants cc, final FunctionNode fn, final Label functionStart, final int slot) {
1834 final Symbol symbol = initializeInternalFunctionOrSplitParameter(cc, fn, functionStart, slot);
1835 // Internal function params (:callee, this, and :varargs) are never expanded to multiple slots
1836 assert symbol.getFirstSlot() == slot;
1837 }
1838
1839 private Symbol initializeInternalFunctionOrSplitParameter(final CompilerConstants cc, final FunctionNode fn, final Label functionStart, final int slot) {
1840 final Symbol symbol = fn.getBody().getExistingSymbol(cc.symbolName());
1841 final Type type = Type.typeFor(cc.type());
1842 method.initializeMethodParameter(symbol, type, functionStart);
1843 method.onLocalStore(type, slot);
1844 return symbol;
1845 }
1846
1847 /**
1848 * Parameters come into the method packed into local variable slots next to each other. Nashorn on the other hand
1849 * can use 1-6 slots for a local variable depending on all the types it needs to store. When this method is invoked,
1850 * the symbols are already allocated such wider slots, but the values are still in tightly packed incoming slots,
1851 * and we need to spread them into their new locations.
1852 * @param function the function for which parameter-spreading code needs to be emitted
1853 */
1854 private void expandParameterSlots(final FunctionNode function) {
1855 final List<IdentNode> parameters = function.getParameters();
1856 // Calculate the total number of incoming parameter slots
1857 int currentIncomingSlot = function.needsCallee() ? 2 : 1;
1858 for(final IdentNode parameter: parameters) {
1859 currentIncomingSlot += parameter.getType().getSlots();
1860 }
1861 // Starting from last parameter going backwards, move the parameter values into their new slots.
1862 for(int i = parameters.size(); i-- > 0;) {
1863 final IdentNode parameter = parameters.get(i);
1864 final Type parameterType = parameter.getType();
1865 final int typeWidth = parameterType.getSlots();
1866 currentIncomingSlot -= typeWidth;
1867 final Symbol symbol = parameter.getSymbol();
1868 final int slotCount = symbol.slotCount();
1869 assert slotCount > 0;
1870 // Scoped parameters must not hold more than one value
1871 assert symbol.isBytecodeLocal() || slotCount == typeWidth;
1872
1873 // Mark it as having its value stored into it by the method invocation.
1874 method.onLocalStore(parameterType, currentIncomingSlot);
1875 if(currentIncomingSlot != symbol.getSlot(parameterType)) {
1876 method.load(parameterType, currentIncomingSlot);
1877 method.store(symbol, parameterType);
1878 }
1879 }
1880 }
1881
1882 private void initArguments(final FunctionNode function) {
1883 method.loadCompilerConstant(VARARGS);
1884 if (function.needsCallee()) {
1885 method.loadCompilerConstant(CALLEE);
1886 } else {
1887 // If function is strict mode, "arguments.callee" is not populated, so we don't necessarily need the
1888 // caller.
1889 assert function.isStrict();
1890 method.loadNull();
1891 }
1892 method.load(function.getParameters().size());
1893 globalAllocateArguments();
1894 method.storeCompilerConstant(ARGUMENTS);
1895 }
1896
1897 private boolean skipFunction(final FunctionNode functionNode) {
1898 final ScriptEnvironment env = compiler.getScriptEnvironment();
1899 final boolean lazy = env._lazy_compilation;
1900 final boolean onDemand = compiler.isOnDemandCompilation();
1901
1902 // If this is on-demand or lazy compilation, don't compile a nested (not topmost) function.
1903 if((onDemand || lazy) && lc.getOutermostFunction() != functionNode) {
1904 return true;
1905 }
1906
1907 // If lazy compiling with optimistic types, don't compile the program eagerly either. It will soon be
1908 // invalidated anyway. In presence of a class cache, this further means that an obsoleted program version
1909 // lingers around. Also, currently loading previously persisted optimistic types information only works if
1910 // we're on-demand compiling a function, so with this strategy the :program method can also have the warmup
1911 // benefit of using previously persisted types.
1912 //
1913 // NOTE that this means the first compiled class will effectively just have a :createProgramFunction method, and
1914 // the RecompilableScriptFunctionData (RSFD) object in its constants array. It won't even have the :program
1915 // method. This is by design. It does mean that we're wasting one compiler execution (and we could minimize this
1916 // by just running it up to scope depth calculation, which creates the RSFDs and then this limited codegen).
1917 // We could emit an initial separate compile unit with the initial version of :program in it to better utilize
1918 // the compilation pipeline, but that would need more invasive changes, as currently the assumption that
1919 // :program is emitted into the first compilation unit of the function lives in many places.
1920 return !onDemand && lazy && env._optimistic_types && functionNode.isProgram();
1921 }
1922
1923 @Override
1924 public boolean enterFunctionNode(final FunctionNode functionNode) {
1925 final int fnId = functionNode.getId();
1926
1927 if (skipFunction(functionNode)) {
1928 // In case we are not generating code for the function, we must create or retrieve the function object and
1929 // load it on the stack here.
1930 newFunctionObject(functionNode, false);
1931 return false;
1932 }
1933
1934 final String fnName = functionNode.getName();
1935
1936 // NOTE: we only emit the method for a function with the given name once. We can have multiple functions with
1937 // the same name as a result of inlining finally blocks. However, in the future -- with type specialization,
1938 // notably -- we might need to check for both name *and* signature. Of course, even that might not be
1939 // sufficient; the function might have a code dependency on the type of the variables in its enclosing scopes,
1940 // and the type of such a variable can be different in catch and finally blocks. So, in the future we will have
1941 // to decide to either generate a unique method for each inlined copy of the function, maybe figure out its
1942 // exact type closure and deduplicate based on that, or just decide that functions in finally blocks aren't
1943 // worth it, and generate one method with most generic type closure.
1944 if (!emittedMethods.contains(fnName)) {
1945 log.info("=== BEGIN ", fnName);
1946
1947 assert functionNode.getCompileUnit() != null : "no compile unit for " + fnName + " " + Debug.id(functionNode);
1948 unit = lc.pushCompileUnit(functionNode.getCompileUnit());
1949 assert lc.hasCompileUnits();
1950
1951 final ClassEmitter classEmitter = unit.getClassEmitter();
1952 pushMethodEmitter(isRestOf() ? classEmitter.restOfMethod(functionNode) : classEmitter.method(functionNode));
1953 method.setPreventUndefinedLoad();
1954 if(useOptimisticTypes()) {
1955 lc.pushUnwarrantedOptimismHandlers();
1956 }
1957
1958 // new method - reset last line number
1959 lastLineNumber = -1;
1960
1961 method.begin();
1962
1963 if (isRestOf()) {
1964 final ContinuationInfo ci = new ContinuationInfo();
1965 fnIdToContinuationInfo.put(fnId, ci);
1966 method.gotoLoopStart(ci.getHandlerLabel());
1967 }
1968 }
1969
1970 return true;
1971 }
1972
1973 private void pushMethodEmitter(final MethodEmitter newMethod) {
1974 method = lc.pushMethodEmitter(newMethod);
1975 catchLabels.push(METHOD_BOUNDARY);
1976 }
1977
1978 private void popMethodEmitter() {
1979 method = lc.popMethodEmitter(method);
1980 assert catchLabels.peek() == METHOD_BOUNDARY;
1981 catchLabels.pop();
1982 }
1983
1984 @Override
1985 public Node leaveFunctionNode(final FunctionNode functionNode) {
1986 try {
1987 final boolean markOptimistic;
1988 if (emittedMethods.add(functionNode.getName())) {
1989 markOptimistic = generateUnwarrantedOptimismExceptionHandlers(functionNode);
1990 generateContinuationHandler();
1991 method.end(); // wrap up this method
1992 unit = lc.popCompileUnit(functionNode.getCompileUnit());
1993 popMethodEmitter();
1994 log.info("=== END ", functionNode.getName());
1995 } else {
1996 markOptimistic = false;
1997 }
1998
1999 FunctionNode newFunctionNode = functionNode.setState(lc, CompilationState.BYTECODE_GENERATED);
2000 if (markOptimistic) {
2001 newFunctionNode = newFunctionNode.setFlag(lc, FunctionNode.IS_DEOPTIMIZABLE);
2002 }
2003
2004 newFunctionObject(newFunctionNode, true);
2005 return newFunctionNode;
2006 } catch (final Throwable t) {
2007 Context.printStackTrace(t);
2008 final VerifyError e = new VerifyError("Code generation bug in \"" + functionNode.getName() + "\": likely stack misaligned: " + t + " " + functionNode.getSource().getName());
2009 e.initCause(t);
2010 throw e;
2011 }
2012 }
2013
2014 @Override
2015 public boolean enterIfNode(final IfNode ifNode) {
2016 if(!method.isReachable()) {
2017 return false;
2018 }
2019 enterStatement(ifNode);
2020
2021 final Expression test = ifNode.getTest();
2022 final Block pass = ifNode.getPass();
2023 final Block fail = ifNode.getFail();
2024
2025 if (Expression.isAlwaysTrue(test)) {
2026 loadAndDiscard(test);
2027 pass.accept(this);
2028 return false;
2029 } else if (Expression.isAlwaysFalse(test)) {
2030 loadAndDiscard(test);
2031 if (fail != null) {
2032 fail.accept(this);
2033 }
2034 return false;
2035 }
2036
2037 final boolean hasFailConversion = LocalVariableConversion.hasLiveConversion(ifNode);
2038
2039 final Label failLabel = new Label("if_fail");
2040 final Label afterLabel = (fail == null && !hasFailConversion) ? null : new Label("if_done");
2041
2042 emitBranch(test, failLabel, false);
2043
2044 pass.accept(this);
2045 if(method.isReachable() && afterLabel != null) {
2046 method._goto(afterLabel); //don't fallthru to fail block
2047 }
2048 method.label(failLabel);
2049
2050 if (fail != null) {
2051 fail.accept(this);
2052 } else if(hasFailConversion) {
2053 method.beforeJoinPoint(ifNode);
2054 }
2055
2056 if(afterLabel != null && afterLabel.isReachable()) {
2057 method.label(afterLabel);
2058 }
2059
2060 return false;
2061 }
2062
2063 private void emitBranch(final Expression test, final Label label, final boolean jumpWhenTrue) {
2064 new BranchOptimizer(this, method).execute(test, label, jumpWhenTrue);
2065 }
2066
2067 private void enterStatement(final Statement statement) {
2068 lineNumber(statement);
2069 }
2070
2071 private void lineNumber(final Statement statement) {
2072 lineNumber(statement.getLineNumber());
2073 }
2074
2075 private void lineNumber(final int lineNumber) {
2076 if (lineNumber != lastLineNumber && lineNumber != Node.NO_LINE_NUMBER) {
2077 method.lineNumber(lineNumber);
2078 lastLineNumber = lineNumber;
2079 }
2080 }
2081
2082 int getLastLineNumber() {
2083 return lastLineNumber;
2084 }
2085
2086 /**
2087 * Load a list of nodes as an array of a specific type
2088 * The array will contain the visited nodes.
2089 *
2090 * @param arrayLiteralNode the array of contents
2091 * @param arrayType the type of the array, e.g. ARRAY_NUMBER or ARRAY_OBJECT
2092 *
2093 * @return the method generator that was used
2094 */
2095 private MethodEmitter loadArray(final ArrayLiteralNode arrayLiteralNode, final ArrayType arrayType) {
2096 assert arrayType == Type.INT_ARRAY || arrayType == Type.LONG_ARRAY || arrayType == Type.NUMBER_ARRAY || arrayType == Type.OBJECT_ARRAY;
2097
2098 final Expression[] nodes = arrayLiteralNode.getValue();
2099 final Object presets = arrayLiteralNode.getPresets();
2100 final int[] postsets = arrayLiteralNode.getPostsets();
2101 final Class<?> type = arrayType.getTypeClass();
2102 final List<ArrayUnit> units = arrayLiteralNode.getUnits();
2103
2104 loadConstant(presets);
2105
2106 final Type elementType = arrayType.getElementType();
2107
2108 if (units != null) {
2109 final MethodEmitter savedMethod = method;
2110 final FunctionNode currentFunction = lc.getCurrentFunction();
2111
2112 for (final ArrayUnit arrayUnit : units) {
2113 unit = lc.pushCompileUnit(arrayUnit.getCompileUnit());
2114
2115 final String className = unit.getUnitClassName();
2116 assert unit != null;
2117 final String name = currentFunction.uniqueName(SPLIT_PREFIX.symbolName());
2118 final String signature = methodDescriptor(type, ScriptFunction.class, Object.class, ScriptObject.class, type);
2119
2120 pushMethodEmitter(unit.getClassEmitter().method(EnumSet.of(Flag.PUBLIC, Flag.STATIC), name, signature));
2121
2122 method.setFunctionNode(currentFunction);
2123 method.begin();
2124
2125 defineCommonSplitMethodParameters();
2126 defineSplitMethodParameter(CompilerConstants.SPLIT_ARRAY_ARG.slot(), arrayType);
2127
2128 // NOTE: when this is no longer needed, SplitIntoFunctions will no longer have to add IS_SPLIT
2129 // to synthetic functions, and FunctionNode.needsCallee() will no longer need to test for isSplit().
2130 final int arraySlot = fixScopeSlot(currentFunction, 3);
2131
2132 lc.enterSplitNode();
2133
2134 for (int i = arrayUnit.getLo(); i < arrayUnit.getHi(); i++) {
2135 method.load(arrayType, arraySlot);
2136 storeElement(nodes, elementType, postsets[i]);
2137 }
2138
2139 method.load(arrayType, arraySlot);
2140 method._return();
2141 lc.exitSplitNode();
2142 method.end();
2143 lc.releaseSlots();
2144 popMethodEmitter();
2145
2146 assert method == savedMethod;
2147 method.loadCompilerConstant(CALLEE);
2148 method.swap();
2149 method.loadCompilerConstant(THIS);
2150 method.swap();
2151 method.loadCompilerConstant(SCOPE);
2152 method.swap();
2153 method.invokestatic(className, name, signature);
2154
2155 unit = lc.popCompileUnit(unit);
2156 }
2157
2158 return method;
2159 }
2160
2161 if(postsets.length > 0) {
2162 final int arraySlot = method.getUsedSlotsWithLiveTemporaries();
2163 method.storeTemp(arrayType, arraySlot);
2164 for (final int postset : postsets) {
2165 method.load(arrayType, arraySlot);
2166 storeElement(nodes, elementType, postset);
2167 }
2168 method.load(arrayType, arraySlot);
2169 }
2170 return method;
2171 }
2172
2173 private void storeElement(final Expression[] nodes, final Type elementType, final int index) {
2174 method.load(index);
2175
2176 final Expression element = nodes[index];
2177
2178 if (element == null) {
2179 method.loadEmpty(elementType);
2180 } else {
2181 loadExpressionAsType(element, elementType);
2182 }
2183
2184 method.arraystore();
2185 }
2186
2187 private MethodEmitter loadArgsArray(final List<Expression> args) {
2188 final Object[] array = new Object[args.size()];
2189 loadConstant(array);
2190
2191 for (int i = 0; i < args.size(); i++) {
2192 method.dup();
2193 method.load(i);
2194 loadExpression(args.get(i), TypeBounds.OBJECT); // variable arity methods always take objects
2195 method.arraystore();
2196 }
2197
2198 return method;
2199 }
2200
2201 /**
2202 * Load a constant from the constant array. This is only public to be callable from the objects
2203 * subpackage. Do not call directly.
2204 *
2205 * @param string string to load
2206 */
2207 void loadConstant(final String string) {
2208 final String unitClassName = unit.getUnitClassName();
2209 final ClassEmitter classEmitter = unit.getClassEmitter();
2210 final int index = compiler.getConstantData().add(string);
2211
2212 method.load(index);
2213 method.invokestatic(unitClassName, GET_STRING.symbolName(), methodDescriptor(String.class, int.class));
2214 classEmitter.needGetConstantMethod(String.class);
2215 }
2216
2217 /**
2218 * Load a constant from the constant array. This is only public to be callable from the objects
2219 * subpackage. Do not call directly.
2220 *
2221 * @param object object to load
2222 */
2223 void loadConstant(final Object object) {
2224 loadConstant(object, unit, method);
2225 }
2226
2227 private void loadConstant(final Object object, final CompileUnit compileUnit, final MethodEmitter methodEmitter) {
2228 final String unitClassName = compileUnit.getUnitClassName();
2229 final ClassEmitter classEmitter = compileUnit.getClassEmitter();
2230 final int index = compiler.getConstantData().add(object);
2231 final Class<?> cls = object.getClass();
2232
2233 if (cls == PropertyMap.class) {
2234 methodEmitter.load(index);
2235 methodEmitter.invokestatic(unitClassName, GET_MAP.symbolName(), methodDescriptor(PropertyMap.class, int.class));
2236 classEmitter.needGetConstantMethod(PropertyMap.class);
2237 } else if (cls.isArray()) {
2238 methodEmitter.load(index);
2239 final String methodName = ClassEmitter.getArrayMethodName(cls);
2240 methodEmitter.invokestatic(unitClassName, methodName, methodDescriptor(cls, int.class));
2241 classEmitter.needGetConstantMethod(cls);
2242 } else {
2243 methodEmitter.loadConstants().load(index).arrayload();
2244 if (object instanceof ArrayData) {
2245 // avoid cast to non-public ArrayData subclass
2246 methodEmitter.checkcast(ArrayData.class);
2247 methodEmitter.invoke(virtualCallNoLookup(ArrayData.class, "copy", ArrayData.class));
2248 } else if (cls != Object.class) {
2249 methodEmitter.checkcast(cls);
2250 }
2251 }
2252 }
2253
2254 // literal values
2255 private void loadLiteral(final LiteralNode<?> node, final TypeBounds resultBounds) {
2256 final Object value = node.getValue();
2257
2258 if (value == null) {
2259 method.loadNull();
2260 } else if (value instanceof Undefined) {
2261 method.loadUndefined(resultBounds.within(Type.OBJECT));
2262 } else if (value instanceof String) {
2263 final String string = (String)value;
2264
2265 if (string.length() > MethodEmitter.LARGE_STRING_THRESHOLD / 3) { // 3 == max bytes per encoded char
2266 loadConstant(string);
2267 } else {
2268 method.load(string);
2269 }
2270 } else if (value instanceof RegexToken) {
2271 loadRegex((RegexToken)value);
2272 } else if (value instanceof Boolean) {
2273 method.load((Boolean)value);
2274 } else if (value instanceof Integer) {
2275 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) {
2276 method.load((Integer)value);
2277 method.convert(Type.OBJECT);
2278 } else if(!resultBounds.canBeNarrowerThan(Type.NUMBER)) {
2279 method.load(((Integer)value).doubleValue());
2280 } else if(!resultBounds.canBeNarrowerThan(Type.LONG)) {
2281 method.load(((Integer)value).longValue());
2282 } else {
2283 method.load((Integer)value);
2284 }
2285 } else if (value instanceof Long) {
2286 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) {
2287 method.load((Long)value);
2288 method.convert(Type.OBJECT);
2289 } else if(!resultBounds.canBeNarrowerThan(Type.NUMBER)) {
2290 method.load(((Long)value).doubleValue());
2291 } else {
2292 method.load((Long)value);
2293 }
2294 } else if (value instanceof Double) {
2295 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) {
2296 method.load((Double)value);
2297 method.convert(Type.OBJECT);
2298 } else {
2299 method.load((Double)value);
2300 }
2301 } else if (node instanceof ArrayLiteralNode) {
2302 final ArrayLiteralNode arrayLiteral = (ArrayLiteralNode)node;
2303 final ArrayType atype = arrayLiteral.getArrayType();
2304 loadArray(arrayLiteral, atype);
2305 globalAllocateArray(atype);
2306 } else {
2307 throw new UnsupportedOperationException("Unknown literal for " + node.getClass() + " " + value.getClass() + " " + value);
2308 }
2309 }
2310
2311 private MethodEmitter loadRegexToken(final RegexToken value) {
2312 method.load(value.getExpression());
2313 method.load(value.getOptions());
2314 return globalNewRegExp();
2315 }
2316
2317 private MethodEmitter loadRegex(final RegexToken regexToken) {
2318 if (regexFieldCount > MAX_REGEX_FIELDS) {
2319 return loadRegexToken(regexToken);
2320 }
2321 // emit field
2322 final String regexName = lc.getCurrentFunction().uniqueName(REGEX_PREFIX.symbolName());
2323 final ClassEmitter classEmitter = unit.getClassEmitter();
2324
2325 classEmitter.field(EnumSet.of(PRIVATE, STATIC), regexName, Object.class);
2326 regexFieldCount++;
2327
2328 // get field, if null create new regex, finally clone regex object
2329 method.getStatic(unit.getUnitClassName(), regexName, typeDescriptor(Object.class));
2330 method.dup();
2331 final Label cachedLabel = new Label("cached");
2332 method.ifnonnull(cachedLabel);
2333
2334 method.pop();
2335 loadRegexToken(regexToken);
2336 method.dup();
2337 method.putStatic(unit.getUnitClassName(), regexName, typeDescriptor(Object.class));
2338
2339 method.label(cachedLabel);
2340 globalRegExpCopy();
2341
2342 return method;
2343 }
2344
2345 /**
2346 * Check if a property value contains a particular program point
2347 * @param value value
2348 * @param pp program point
2349 * @return true if it's there.
2350 */
2351 private static boolean propertyValueContains(final Expression value, final int pp) {
2352 return new Supplier<Boolean>() {
2353 boolean contains;
2354
2355 @Override
2356 public Boolean get() {
2357 value.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) {
2358 @Override
2359 public boolean enterFunctionNode(final FunctionNode functionNode) {
2360 return false;
2361 }
2362
2363 @Override
2364 public boolean enterObjectNode(final ObjectNode objectNode) {
2365 return false;
2366 }
2367
2368 @Override
2369 public boolean enterDefault(final Node node) {
2370 if (contains) {
2371 return false;
2372 }
2373 if (node instanceof Optimistic && ((Optimistic)node).getProgramPoint() == pp) {
2374 contains = true;
2375 return false;
2376 }
2377 return true;
2378 }
2379 });
2380
2381 return contains;
2382 }
2383 }.get();
2384 }
2385
2386 private void loadObjectNode(final ObjectNode objectNode) {
2387 final List<PropertyNode> elements = objectNode.getElements();
2388
2389 final List<MapTuple<Expression>> tuples = new ArrayList<>();
2390 final List<PropertyNode> gettersSetters = new ArrayList<>();
2391 final int ccp = getCurrentContinuationEntryPoint();
2392
2393 Expression protoNode = null;
2394 boolean restOfProperty = false;
2395
2396 for (final PropertyNode propertyNode : elements) {
2397 final Expression value = propertyNode.getValue();
2398 final String key = propertyNode.getKeyName();
2399 // Just use a pseudo-symbol. We just need something non null; use the name and zero flags.
2400 final Symbol symbol = value == null ? null : new Symbol(key, 0);
2401
2402 if (value == null) {
2403 gettersSetters.add(propertyNode);
2404 } else if (propertyNode.getKey() instanceof IdentNode &&
2405 key.equals(ScriptObject.PROTO_PROPERTY_NAME)) {
2406 // ES6 draft compliant __proto__ inside object literal
2407 // Identifier key and name is __proto__
2408 protoNode = value;
2409 continue;
2410 }
2411
2412 restOfProperty |=
2413 value != null &&
2414 isValid(ccp) &&
2415 propertyValueContains(value, ccp);
2416
2417 //for literals, a value of null means object type, i.e. the value null or getter setter function
2418 //(I think)
2419 final Class<?> valueType = (OBJECT_FIELDS_ONLY || value == null || value.getType().isBoolean()) ? Object.class : value.getType().getTypeClass();
2420 tuples.add(new MapTuple<Expression>(key, symbol, Type.typeFor(valueType), value) {
2421 @Override
2422 public Class<?> getValueType() {
2423 return type.getTypeClass();
2424 }
2425 });
2426 }
2427
2428 final ObjectCreator<?> oc;
2429 if (elements.size() > OBJECT_SPILL_THRESHOLD) {
2430 oc = new SpillObjectCreator(this, tuples);
2431 } else {
2432 oc = new FieldObjectCreator<Expression>(this, tuples) {
2433 @Override
2434 protected void loadValue(final Expression node, final Type type) {
2435 loadExpressionAsType(node, type);
2436 }};
2437 }
2438 oc.makeObject(method);
2439
2440 //if this is a rest of method and our continuation point was found as one of the values
2441 //in the properties above, we need to reset the map to oc.getMap() in the continuation
2442 //handler
2443 if (restOfProperty) {
2444 final ContinuationInfo ci = getContinuationInfo();
2445 // Can be set at most once for a single rest-of method
2446 assert ci.getObjectLiteralMap() == null;
2447 ci.setObjectLiteralMap(oc.getMap());
2448 ci.setObjectLiteralStackDepth(method.getStackSize());
2449 }
2450
2451 method.dup();
2452 if (protoNode != null) {
2453 loadExpressionAsObject(protoNode);
2454 // take care of { __proto__: 34 } or some such!
2455 method.convert(Type.OBJECT);
2456 method.invoke(ScriptObject.SET_PROTO_FROM_LITERAL);
2457 } else {
2458 method.invoke(ScriptObject.SET_GLOBAL_OBJECT_PROTO);
2459 }
2460
2461 for (final PropertyNode propertyNode : gettersSetters) {
2462 final FunctionNode getter = propertyNode.getGetter();
2463 final FunctionNode setter = propertyNode.getSetter();
2464
2465 assert getter != null || setter != null;
2466
2467 method.dup().loadKey(propertyNode.getKey());
2468 if (getter == null) {
2469 method.loadNull();
2470 } else {
2471 getter.accept(this);
2472 }
2473
2474 if (setter == null) {
2475 method.loadNull();
2476 } else {
2477 setter.accept(this);
2478 }
2479
2480 method.invoke(ScriptObject.SET_USER_ACCESSORS);
2481 }
2482 }
2483
2484 @Override
2485 public boolean enterReturnNode(final ReturnNode returnNode) {
2486 if(!method.isReachable()) {
2487 return false;
2488 }
2489 enterStatement(returnNode);
2490
2491 method.registerReturn();
2492
2493 final Type returnType = lc.getCurrentFunction().getReturnType();
2494
2495 final Expression expression = returnNode.getExpression();
2496 if (expression != null) {
2497 loadExpressionUnbounded(expression);
2498 } else {
2499 method.loadUndefined(returnType);
2500 }
2501
2502 method._return(returnType);
2503
2504 return false;
2505 }
2506
2507 private boolean undefinedCheck(final RuntimeNode runtimeNode, final List<Expression> args) {
2508 final Request request = runtimeNode.getRequest();
2509
2510 if (!Request.isUndefinedCheck(request)) {
2511 return false;
2512 }
2513
2514 final Expression lhs = args.get(0);
2515 final Expression rhs = args.get(1);
2516
2517 final Symbol lhsSymbol = lhs instanceof IdentNode ? ((IdentNode)lhs).getSymbol() : null;
2518 final Symbol rhsSymbol = rhs instanceof IdentNode ? ((IdentNode)rhs).getSymbol() : null;
2519 // One must be a "undefined" identifier, otherwise we can't get here
2520 assert lhsSymbol != null || rhsSymbol != null;
2521
2522 final Symbol undefinedSymbol;
2523 if (isUndefinedSymbol(lhsSymbol)) {
2524 undefinedSymbol = lhsSymbol;
2525 } else {
2526 assert isUndefinedSymbol(rhsSymbol);
2527 undefinedSymbol = rhsSymbol;
2528 }
2529
2530 assert undefinedSymbol != null; //remove warning
2531 if (!undefinedSymbol.isScope()) {
2532 return false; //disallow undefined as local var or parameter
2533 }
2534
2535 if (lhsSymbol == undefinedSymbol && lhs.getType().isPrimitive()) {
2536 //we load the undefined first. never mind, because this will deoptimize anyway
2537 return false;
2538 }
2539
2540 if(isDeoptimizedExpression(lhs)) {
2541 // This is actually related to "lhs.getType().isPrimitive()" above: any expression being deoptimized in
2542 // the current chain of rest-of compilations used to have a type narrower than Object (so it was primitive).
2543 // We must not perform undefined check specialization for them, as then we'd violate the basic rule of
2544 // "Thou shalt not alter the stack shape between a deoptimized method and any of its (transitive) rest-ofs."
2545 return false;
2546 }
2547
2548 //make sure that undefined has not been overridden or scoped as a local var
2549 //between us and global
2550 if (!compiler.isGlobalSymbol(lc.getCurrentFunction(), "undefined")) {
2551 return false;
2552 }
2553
2554 final boolean isUndefinedCheck = request == Request.IS_UNDEFINED;
2555 final Expression expr = undefinedSymbol == lhsSymbol ? rhs : lhs;
2556 if (expr.getType().isPrimitive()) {
2557 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
2558 method.load(!isUndefinedCheck);
2559 } else {
2560 final Label checkTrue = new Label("ud_check_true");
2561 final Label end = new Label("end");
2562 loadExpressionAsObject(expr);
2563 method.loadUndefined(Type.OBJECT);
2564 method.if_acmpeq(checkTrue);
2565 method.load(!isUndefinedCheck);
2566 method._goto(end);
2567 method.label(checkTrue);
2568 method.load(isUndefinedCheck);
2569 method.label(end);
2570 }
2571
2572 return true;
2573 }
2574
2575 private static boolean isUndefinedSymbol(final Symbol symbol) {
2576 return symbol != null && "undefined".equals(symbol.getName());
2577 }
2578
2579 private static boolean isNullLiteral(final Node node) {
2580 return node instanceof LiteralNode<?> && ((LiteralNode<?>) node).isNull();
2581 }
2582
2583 private boolean nullCheck(final RuntimeNode runtimeNode, final List<Expression> args) {
2584 final Request request = runtimeNode.getRequest();
2585
2586 if (!Request.isEQ(request) && !Request.isNE(request)) {
2587 return false;
2588 }
2589
2590 assert args.size() == 2 : "EQ or NE or TYPEOF need two args";
2591
2592 Expression lhs = args.get(0);
2593 Expression rhs = args.get(1);
2594
2595 if (isNullLiteral(lhs)) {
2596 final Expression tmp = lhs;
2597 lhs = rhs;
2598 rhs = tmp;
2599 }
2600
2601 if (!isNullLiteral(rhs)) {
2602 return false;
2603 }
2604
2605 if (!lhs.getType().isObject()) {
2606 return false;
2607 }
2608
2609 if(isDeoptimizedExpression(lhs)) {
2610 // This is actually related to "!lhs.getType().isObject()" above: any expression being deoptimized in
2611 // the current chain of rest-of compilations used to have a type narrower than Object. We must not
2612 // perform null check specialization for them, as then we'd no longer be loading aconst_null on stack
2613 // and thus violate the basic rule of "Thou shalt not alter the stack shape between a deoptimized
2614 // method and any of its (transitive) rest-ofs."
2615 // NOTE also that if we had a representation for well-known constants (e.g. null, 0, 1, -1, etc.) in
2616 // Label$Stack.localLoads then this wouldn't be an issue, as we would never (somewhat ridiculously)
2617 // allocate a temporary local to hold the result of aconst_null before attempting an optimistic
2618 // operation.
2619 return false;
2620 }
2621
2622 // this is a null literal check, so if there is implicit coercion
2623 // involved like {D}x=null, we will fail - this is very rare
2624 final Label trueLabel = new Label("trueLabel");
2625 final Label falseLabel = new Label("falseLabel");
2626 final Label endLabel = new Label("end");
2627
2628 loadExpressionUnbounded(lhs); //lhs
2629 final Label popLabel;
2630 if (!Request.isStrict(request)) {
2631 method.dup(); //lhs lhs
2632 popLabel = new Label("pop");
2633 } else {
2634 popLabel = null;
2635 }
2636
2637 if (Request.isEQ(request)) {
2638 method.ifnull(!Request.isStrict(request) ? popLabel : trueLabel);
2639 if (!Request.isStrict(request)) {
2640 method.loadUndefined(Type.OBJECT);
2641 method.if_acmpeq(trueLabel);
2642 }
2643 method.label(falseLabel);
2644 method.load(false);
2645 method._goto(endLabel);
2646 if (!Request.isStrict(request)) {
2647 method.label(popLabel);
2648 method.pop();
2649 }
2650 method.label(trueLabel);
2651 method.load(true);
2652 method.label(endLabel);
2653 } else if (Request.isNE(request)) {
2654 method.ifnull(!Request.isStrict(request) ? popLabel : falseLabel);
2655 if (!Request.isStrict(request)) {
2656 method.loadUndefined(Type.OBJECT);
2657 method.if_acmpeq(falseLabel);
2658 }
2659 method.label(trueLabel);
2660 method.load(true);
2661 method._goto(endLabel);
2662 if (!Request.isStrict(request)) {
2663 method.label(popLabel);
2664 method.pop();
2665 }
2666 method.label(falseLabel);
2667 method.load(false);
2668 method.label(endLabel);
2669 }
2670
2671 assert runtimeNode.getType().isBoolean();
2672 method.convert(runtimeNode.getType());
2673
2674 return true;
2675 }
2676
2677 /**
2678 * Was this expression or any of its subexpressions deoptimized in the current recompilation chain of rest-of methods?
2679 * @param rootExpr the expression being tested
2680 * @return true if the expression or any of its subexpressions was deoptimized in the current recompilation chain.
2681 */
2682 private boolean isDeoptimizedExpression(final Expression rootExpr) {
2683 if(!isRestOf()) {
2684 return false;
2685 }
2686 return new Supplier<Boolean>() {
2687 boolean contains;
2688 @Override
2689 public Boolean get() {
2690 rootExpr.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) {
2691 @Override
2692 public boolean enterFunctionNode(final FunctionNode functionNode) {
2693 return false;
2694 }
2695 @Override
2696 public boolean enterDefault(final Node node) {
2697 if(!contains && node instanceof Optimistic) {
2698 final int pp = ((Optimistic)node).getProgramPoint();
2699 contains = isValid(pp) && isContinuationEntryPoint(pp);
2700 }
2701 return !contains;
2702 }
2703 });
2704 return contains;
2705 }
2706 }.get();
2707 }
2708
2709 private void loadRuntimeNode(final RuntimeNode runtimeNode) {
2710 final List<Expression> args = new ArrayList<>(runtimeNode.getArgs());
2711 if (nullCheck(runtimeNode, args)) {
2712 return;
2713 } else if(undefinedCheck(runtimeNode, args)) {
2714 return;
2715 }
2716 // Revert a false undefined check to a strict equality check
2717 final RuntimeNode newRuntimeNode;
2718 final Request request = runtimeNode.getRequest();
2719 if (Request.isUndefinedCheck(request)) {
2720 newRuntimeNode = runtimeNode.setRequest(request == Request.IS_UNDEFINED ? Request.EQ_STRICT : Request.NE_STRICT);
2721 } else {
2722 newRuntimeNode = runtimeNode;
2723 }
2724
2725 new OptimisticOperation(newRuntimeNode, TypeBounds.UNBOUNDED) {
2726 @Override
2727 void loadStack() {
2728 for (final Expression arg : args) {
2729 loadExpression(arg, TypeBounds.OBJECT);
2730 }
2731 }
2732 @Override
2733 void consumeStack() {
2734 method.invokestatic(
2735 CompilerConstants.className(ScriptRuntime.class),
2736 newRuntimeNode.getRequest().toString(),
2737 new FunctionSignature(
2738 false,
2739 false,
2740 newRuntimeNode.getType(),
2741 args.size()).toString());
2742 }
2743 }.emit();
2744
2745 method.convert(newRuntimeNode.getType());
2746 }
2747
2748 private void defineCommonSplitMethodParameters() {
2749 defineSplitMethodParameter(0, CALLEE);
2750 defineSplitMethodParameter(1, THIS);
2751 defineSplitMethodParameter(2, SCOPE);
2752 }
2753
2754 private void defineSplitMethodParameter(final int slot, final CompilerConstants cc) {
2755 defineSplitMethodParameter(slot, Type.typeFor(cc.type()));
2756 }
2757
2758 private void defineSplitMethodParameter(final int slot, final Type type) {
2759 method.defineBlockLocalVariable(slot, slot + type.getSlots());
2760 method.onLocalStore(type, slot);
2761 }
2762
2763 private int fixScopeSlot(final FunctionNode functionNode, final int extraSlot) {
2764 // TODO hack to move the scope to the expected slot (needed because split methods reuse the same slots as the root method)
2765 final int actualScopeSlot = functionNode.compilerConstant(SCOPE).getSlot(SCOPE_TYPE);
2766 final int defaultScopeSlot = SCOPE.slot();
2767 int newExtraSlot = extraSlot;
2768 if (actualScopeSlot != defaultScopeSlot) {
2769 if (actualScopeSlot == extraSlot) {
2770 newExtraSlot = extraSlot + 1;
2771 method.defineBlockLocalVariable(newExtraSlot, newExtraSlot + 1);
2772 method.load(Type.OBJECT, extraSlot);
2773 method.storeHidden(Type.OBJECT, newExtraSlot);
2774 } else {
2775 method.defineBlockLocalVariable(actualScopeSlot, actualScopeSlot + 1);
2776 }
2777 method.load(SCOPE_TYPE, defaultScopeSlot);
2778 method.storeCompilerConstant(SCOPE);
2779 }
2780 return newExtraSlot;
2781 }
2782
2783 @Override
2784 public boolean enterSplitReturn(final SplitReturn splitReturn) {
2785 if (method.isReachable()) {
2786 method.loadUndefined(lc.getCurrentFunction().getReturnType())._return();
2787 }
2788 return false;
2789 }
2790
2791 @Override
2792 public boolean enterSetSplitState(final SetSplitState setSplitState) {
2793 if (method.isReachable()) {
2794 method.setSplitState(setSplitState.getState());
2795 }
2796 return false;
2797 }
2798
2799 @Override
2800 public boolean enterSwitchNode(final SwitchNode switchNode) {
2801 if(!method.isReachable()) {
2802 return false;
2803 }
2804 enterStatement(switchNode);
2805
2806 final Expression expression = switchNode.getExpression();
2807 final List<CaseNode> cases = switchNode.getCases();
2808
2809 if (cases.isEmpty()) {
2810 // still evaluate expression for side-effects.
2811 loadAndDiscard(expression);
2812 return false;
2813 }
2814
2815 final CaseNode defaultCase = switchNode.getDefaultCase();
2816 final Label breakLabel = switchNode.getBreakLabel();
2817 final int liveLocalsOnBreak = method.getUsedSlotsWithLiveTemporaries();
2818
2819 if (defaultCase != null && cases.size() == 1) {
2820 // default case only
2821 assert cases.get(0) == defaultCase;
2822 loadAndDiscard(expression);
2823 defaultCase.getBody().accept(this);
2824 method.breakLabel(breakLabel, liveLocalsOnBreak);
2825 return false;
2826 }
2827
2828 // NOTE: it can still change in the tableswitch/lookupswitch case if there's no default case
2829 // but we need to add a synthetic default case for local variable conversions
2830 Label defaultLabel = defaultCase != null ? defaultCase.getEntry() : breakLabel;
2831 final boolean hasSkipConversion = LocalVariableConversion.hasLiveConversion(switchNode);
2832
2833 if (switchNode.isUniqueInteger()) {
2834 // Tree for sorting values.
2835 final TreeMap<Integer, Label> tree = new TreeMap<>();
2836
2837 // Build up sorted tree.
2838 for (final CaseNode caseNode : cases) {
2839 final Node test = caseNode.getTest();
2840
2841 if (test != null) {
2842 final Integer value = (Integer)((LiteralNode<?>)test).getValue();
2843 final Label entry = caseNode.getEntry();
2844
2845 // Take first duplicate.
2846 if (!tree.containsKey(value)) {
2847 tree.put(value, entry);
2848 }
2849 }
2850 }
2851
2852 // Copy values and labels to arrays.
2853 final int size = tree.size();
2854 final Integer[] values = tree.keySet().toArray(new Integer[size]);
2855 final Label[] labels = tree.values().toArray(new Label[size]);
2856
2857 // Discern low, high and range.
2858 final int lo = values[0];
2859 final int hi = values[size - 1];
2860 final long range = (long)hi - (long)lo + 1;
2861
2862 // Find an unused value for default.
2863 int deflt = Integer.MIN_VALUE;
2864 for (final int value : values) {
2865 if (deflt == value) {
2866 deflt++;
2867 } else if (deflt < value) {
2868 break;
2869 }
2870 }
2871
2872 // Load switch expression.
2873 loadExpressionUnbounded(expression);
2874 final Type type = expression.getType();
2875
2876 // If expression not int see if we can convert, if not use deflt to trigger default.
2877 if (!type.isInteger()) {
2878 method.load(deflt);
2879 final Class<?> exprClass = type.getTypeClass();
2880 method.invoke(staticCallNoLookup(ScriptRuntime.class, "switchTagAsInt", int.class, exprClass.isPrimitive()? exprClass : Object.class, int.class));
2881 }
2882
2883 if(hasSkipConversion) {
2884 assert defaultLabel == breakLabel;
2885 defaultLabel = new Label("switch_skip");
2886 }
2887 // TABLESWITCH needs (range + 3) 32-bit values; LOOKUPSWITCH needs ((size * 2) + 2). Choose the one with
2888 // smaller representation, favor TABLESWITCH when they're equal size.
2889 if (range + 1 <= (size * 2) && range <= Integer.MAX_VALUE) {
2890 final Label[] table = new Label[(int)range];
2891 Arrays.fill(table, defaultLabel);
2892 for (int i = 0; i < size; i++) {
2893 final int value = values[i];
2894 table[value - lo] = labels[i];
2895 }
2896
2897 method.tableswitch(lo, hi, defaultLabel, table);
2898 } else {
2899 final int[] ints = new int[size];
2900 for (int i = 0; i < size; i++) {
2901 ints[i] = values[i];
2902 }
2903
2904 method.lookupswitch(defaultLabel, ints, labels);
2905 }
2906 // This is a synthetic "default case" used in absence of actual default case, created if we need to apply
2907 // local variable conversions if neither case is taken.
2908 if(hasSkipConversion) {
2909 method.label(defaultLabel);
2910 method.beforeJoinPoint(switchNode);
2911 method._goto(breakLabel);
2912 }
2913 } else {
2914 final Symbol tagSymbol = switchNode.getTag();
2915 // TODO: we could have non-object tag
2916 final int tagSlot = tagSymbol.getSlot(Type.OBJECT);
2917 loadExpressionAsObject(expression);
2918 method.store(tagSymbol, Type.OBJECT);
2919
2920 for (final CaseNode caseNode : cases) {
2921 final Expression test = caseNode.getTest();
2922
2923 if (test != null) {
2924 method.load(Type.OBJECT, tagSlot);
2925 loadExpressionAsObject(test);
2926 method.invoke(ScriptRuntime.EQ_STRICT);
2927 method.ifne(caseNode.getEntry());
2928 }
2929 }
2930
2931 if (defaultCase != null) {
2932 method._goto(defaultLabel);
2933 } else {
2934 method.beforeJoinPoint(switchNode);
2935 method._goto(breakLabel);
2936 }
2937 }
2938
2939 // First case is only reachable through jump
2940 assert !method.isReachable();
2941
2942 for (final CaseNode caseNode : cases) {
2943 final Label fallThroughLabel;
2944 if(caseNode.getLocalVariableConversion() != null && method.isReachable()) {
2945 fallThroughLabel = new Label("fallthrough");
2946 method._goto(fallThroughLabel);
2947 } else {
2948 fallThroughLabel = null;
2949 }
2950 method.label(caseNode.getEntry());
2951 method.beforeJoinPoint(caseNode);
2952 if(fallThroughLabel != null) {
2953 method.label(fallThroughLabel);
2954 }
2955 caseNode.getBody().accept(this);
2956 }
2957
2958 method.breakLabel(breakLabel, liveLocalsOnBreak);
2959
2960 return false;
2961 }
2962
2963 @Override
2964 public boolean enterThrowNode(final ThrowNode throwNode) {
2965 if(!method.isReachable()) {
2966 return false;
2967 }
2968 enterStatement(throwNode);
2969
2970 if (throwNode.isSyntheticRethrow()) {
2971 method.beforeJoinPoint(throwNode);
2972
2973 //do not wrap whatever this is in an ecma exception, just rethrow it
2974 final IdentNode exceptionExpr = (IdentNode)throwNode.getExpression();
2975 final Symbol exceptionSymbol = exceptionExpr.getSymbol();
2976 method.load(exceptionSymbol, EXCEPTION_TYPE);
2977 method.checkcast(EXCEPTION_TYPE.getTypeClass());
2978 method.athrow();
2979 return false;
2980 }
2981
2982 final Source source = getCurrentSource();
2983 final Expression expression = throwNode.getExpression();
2984 final int position = throwNode.position();
2985 final int line = throwNode.getLineNumber();
2986 final int column = source.getColumn(position);
2987
2988 // NOTE: we first evaluate the expression, and only after it was evaluated do we create the new ECMAException
2989 // object and then somewhat cumbersomely move it beneath the evaluated expression on the stack. The reason for
2990 // this is that if expression is optimistic (or contains an optimistic subexpression), we'd potentially access
2991 // the not-yet-<init>ialized object on the stack from the UnwarrantedOptimismException handler, and bytecode
2992 // verifier forbids that.
2993 loadExpressionAsObject(expression);
2994
2995 method.load(source.getName());
2996 method.load(line);
2997 method.load(column);
2998 method.invoke(ECMAException.CREATE);
2999
3000 method.beforeJoinPoint(throwNode);
3001 method.athrow();
3002
3003 return false;
3004 }
3005
3006 private Source getCurrentSource() {
3007 return lc.getCurrentFunction().getSource();
3008 }
3009
3010 @Override
3011 public boolean enterTryNode(final TryNode tryNode) {
3012 if(!method.isReachable()) {
3013 return false;
3014 }
3015 enterStatement(tryNode);
3016
3017 final Block body = tryNode.getBody();
3018 final List<Block> catchBlocks = tryNode.getCatchBlocks();
3019 final Symbol vmException = tryNode.getException();
3020 final Label entry = new Label("try");
3021 final Label recovery = new Label("catch");
3022 final Label exit = new Label("end_try");
3023 final Label skip = new Label("skip");
3024
3025 method.canThrow(recovery);
3026 // Effect any conversions that might be observed at the entry of the catch node before entering the try node.
3027 // This is because even the first instruction in the try block must be presumed to be able to transfer control
3028 // to the catch block. Note that this doesn't kill the original values; in this regard it works a lot like
3029 // conversions of assignments within the try block.
3030 method.beforeTry(tryNode, recovery);
3031 method.label(entry);
3032 catchLabels.push(recovery);
3033 try {
3034 body.accept(this);
3035 } finally {
3036 assert catchLabels.peek() == recovery;
3037 catchLabels.pop();
3038 }
3039
3040 method.label(exit);
3041 final boolean bodyCanThrow = exit.isAfter(entry);
3042 if(!bodyCanThrow) {
3043 // The body can't throw an exception; don't even bother emitting the catch handlers, they're all dead code.
3044 return false;
3045 }
3046
3047 method._try(entry, exit, recovery, Throwable.class);
3048
3049 if (method.isReachable()) {
3050 method._goto(skip);
3051 }
3052 method._catch(recovery);
3053 method.store(vmException, EXCEPTION_TYPE);
3054
3055 final int catchBlockCount = catchBlocks.size();
3056 final Label afterCatch = new Label("after_catch");
3057 for (int i = 0; i < catchBlockCount; i++) {
3058 assert method.isReachable();
3059 final Block catchBlock = catchBlocks.get(i);
3060
3061 // Because of the peculiarities of the flow control, we need to use an explicit push/enterBlock/leaveBlock
3062 // here.
3063 lc.push(catchBlock);
3064 enterBlock(catchBlock);
3065
3066 final CatchNode catchNode = (CatchNode)catchBlocks.get(i).getStatements().get(0);
3067 final IdentNode exception = catchNode.getException();
3068 final Expression exceptionCondition = catchNode.getExceptionCondition();
3069 final Block catchBody = catchNode.getBody();
3070
3071 new Store<IdentNode>(exception) {
3072 @Override
3073 protected void storeNonDiscard() {
3074 // This expression is neither part of a discard, nor needs to be left on the stack after it was
3075 // stored, so we override storeNonDiscard to be a no-op.
3076 }
3077
3078 @Override
3079 protected void evaluate() {
3080 if (catchNode.isSyntheticRethrow()) {
3081 method.load(vmException, EXCEPTION_TYPE);
3082 return;
3083 }
3084 /*
3085 * If caught object is an instance of ECMAException, then
3086 * bind obj.thrown to the script catch var. Or else bind the
3087 * caught object itself to the script catch var.
3088 */
3089 final Label notEcmaException = new Label("no_ecma_exception");
3090 method.load(vmException, EXCEPTION_TYPE).dup()._instanceof(ECMAException.class).ifeq(notEcmaException);
3091 method.checkcast(ECMAException.class); //TODO is this necessary?
3092 method.getField(ECMAException.THROWN);
3093 method.label(notEcmaException);
3094 }
3095 }.store();
3096
3097 final boolean isConditionalCatch = exceptionCondition != null;
3098 final Label nextCatch;
3099 if (isConditionalCatch) {
3100 loadExpressionAsBoolean(exceptionCondition);
3101 nextCatch = new Label("next_catch");
3102 nextCatch.markAsBreakTarget();
3103 method.ifeq(nextCatch);
3104 } else {
3105 nextCatch = null;
3106 }
3107
3108 catchBody.accept(this);
3109 leaveBlock(catchBlock);
3110 lc.pop(catchBlock);
3111 if(method.isReachable()) {
3112 method._goto(afterCatch);
3113 }
3114 if(nextCatch != null) {
3115 method.breakLabel(nextCatch, lc.getUsedSlotCount());
3116 }
3117 }
3118
3119 assert !method.isReachable();
3120 // afterCatch could be the same as skip, except that we need to establish that the vmException is dead.
3121 method.label(afterCatch);
3122 if(method.isReachable()) {
3123 method.markDeadLocalVariable(vmException);
3124 }
3125 method.label(skip);
3126
3127 // Finally body is always inlined elsewhere so it doesn't need to be emitted
3128 return false;
3129 }
3130
3131 @Override
3132 public boolean enterVarNode(final VarNode varNode) {
3133 if(!method.isReachable()) {
3134 return false;
3135 }
3136 final Expression init = varNode.getInit();
3137 final IdentNode identNode = varNode.getName();
3138 final Symbol identSymbol = identNode.getSymbol();
3139 assert identSymbol != null : "variable node " + varNode + " requires a name with a symbol";
3140 final boolean needsScope = identSymbol.isScope();
3141
3142 if (init == null) {
3143 if (needsScope && varNode.isBlockScoped()) {
3144 // block scoped variables need a DECLARE flag to signal end of temporal dead zone (TDZ)
3145 method.loadCompilerConstant(SCOPE);
3146 method.loadUndefined(Type.OBJECT);
3147 final int flags = CALLSITE_SCOPE | getCallSiteFlags() | (varNode.isBlockScoped() ? CALLSITE_DECLARE : 0);
3148 assert isFastScope(identSymbol);
3149 storeFastScopeVar(identSymbol, flags);
3150 }
3151 return false;
3152 }
3153
3154 enterStatement(varNode);
3155 assert method != null;
3156
3157 if (needsScope) {
3158 method.loadCompilerConstant(SCOPE);
3159 }
3160
3161 if (needsScope) {
3162 loadExpressionUnbounded(init);
3163 // block scoped variables need a DECLARE flag to signal end of temporal dead zone (TDZ)
3164 final int flags = CALLSITE_SCOPE | getCallSiteFlags() | (varNode.isBlockScoped() ? CALLSITE_DECLARE : 0);
3165 if (isFastScope(identSymbol)) {
3166 storeFastScopeVar(identSymbol, flags);
3167 } else {
3168 method.dynamicSet(identNode.getName(), flags, false);
3169 }
3170 } else {
3171 final Type identType = identNode.getType();
3172 if(identType == Type.UNDEFINED) {
3173 // The initializer is either itself undefined (explicit assignment of undefined to undefined),
3174 // or the left hand side is a dead variable.
3175 assert init.getType() == Type.UNDEFINED || identNode.getSymbol().slotCount() == 0;
3176 loadAndDiscard(init);
3177 return false;
3178 }
3179 loadExpressionAsType(init, identType);
3180 storeIdentWithCatchConversion(identNode, identType);
3181 }
3182
3183 return false;
3184 }
3185
3186 private void storeIdentWithCatchConversion(final IdentNode identNode, final Type type) {
3187 // Assignments happening in try/catch blocks need to ensure that they also store a possibly wider typed value
3188 // that will be live at the exit from the try block
3189 final LocalVariableConversion conversion = identNode.getLocalVariableConversion();
3190 final Symbol symbol = identNode.getSymbol();
3191 if(conversion != null && conversion.isLive()) {
3192 assert symbol == conversion.getSymbol();
3193 assert symbol.isBytecodeLocal();
3194 // Only a single conversion from the target type to the join type is expected.
3195 assert conversion.getNext() == null;
3196 assert conversion.getFrom() == type;
3197 // We must propagate potential type change to the catch block
3198 final Label catchLabel = catchLabels.peek();
3199 assert catchLabel != METHOD_BOUNDARY; // ident conversion only exists in try blocks
3200 assert catchLabel.isReachable();
3201 final Type joinType = conversion.getTo();
3202 final Label.Stack catchStack = catchLabel.getStack();
3203 final int joinSlot = symbol.getSlot(joinType);
3204 // With nested try/catch blocks (incl. synthetic ones for finally), we can have a supposed conversion for
3205 // the exception symbol in the nested catch, but it isn't live in the outer catch block, so prevent doing
3206 // conversions for it. E.g. in "try { try { ... } catch(e) { e = 1; } } catch(e2) { ... }", we must not
3207 // introduce an I->O conversion on "e = 1" assignment as "e" is not live in "catch(e2)".
3208 if(catchStack.getUsedSlotsWithLiveTemporaries() > joinSlot) {
3209 method.dup();
3210 method.convert(joinType);
3211 method.store(symbol, joinType);
3212 catchLabel.getStack().onLocalStore(joinType, joinSlot, true);
3213 method.canThrow(catchLabel);
3214 // Store but keep the previous store live too.
3215 method.store(symbol, type, false);
3216 return;
3217 }
3218 }
3219
3220 method.store(symbol, type, true);
3221 }
3222
3223 @Override
3224 public boolean enterWhileNode(final WhileNode whileNode) {
3225 if(!method.isReachable()) {
3226 return false;
3227 }
3228 if(whileNode.isDoWhile()) {
3229 enterDoWhile(whileNode);
3230 } else {
3231 enterStatement(whileNode);
3232 enterForOrWhile(whileNode, null);
3233 }
3234 return false;
3235 }
3236
3237 private void enterForOrWhile(final LoopNode loopNode, final JoinPredecessorExpression modify) {
3238 // NOTE: the usual pattern for compiling test-first loops is "GOTO test; body; test; IFNE body". We use the less
3239 // conventional "test; IFEQ break; body; GOTO test; break;". It has one extra unconditional GOTO in each repeat
3240 // of the loop, but it's not a problem for modern JIT compilers. We do this because our local variable type
3241 // tracking is unfortunately not really prepared for out-of-order execution, e.g. compiling the following
3242 // contrived but legal JavaScript code snippet would fail because the test changes the type of "i" from object
3243 // to double: var i = {valueOf: function() { return 1} }; while(--i >= 0) { ... }
3244 // Instead of adding more complexity to the local variable type tracking, we instead choose to emit this
3245 // different code shape.
3246 final int liveLocalsOnBreak = method.getUsedSlotsWithLiveTemporaries();
3247 final JoinPredecessorExpression test = loopNode.getTest();
3248 if(Expression.isAlwaysFalse(test)) {
3249 loadAndDiscard(test);
3250 return;
3251 }
3252
3253 method.beforeJoinPoint(loopNode);
3254
3255 final Label continueLabel = loopNode.getContinueLabel();
3256 final Label repeatLabel = modify != null ? new Label("for_repeat") : continueLabel;
3257 method.label(repeatLabel);
3258 final int liveLocalsOnContinue = method.getUsedSlotsWithLiveTemporaries();
3259
3260 final Block body = loopNode.getBody();
3261 final Label breakLabel = loopNode.getBreakLabel();
3262 final boolean testHasLiveConversion = test != null && LocalVariableConversion.hasLiveConversion(test);
3263
3264 if(Expression.isAlwaysTrue(test)) {
3265 if(test != null) {
3266 loadAndDiscard(test);
3267 if(testHasLiveConversion) {
3268 method.beforeJoinPoint(test);
3269 }
3270 }
3271 } else if (test != null) {
3272 if (testHasLiveConversion) {
3273 emitBranch(test.getExpression(), body.getEntryLabel(), true);
3274 method.beforeJoinPoint(test);
3275 method._goto(breakLabel);
3276 } else {
3277 emitBranch(test.getExpression(), breakLabel, false);
3278 }
3279 }
3280
3281 body.accept(this);
3282 if(repeatLabel != continueLabel) {
3283 emitContinueLabel(continueLabel, liveLocalsOnContinue);
3284 }
3285
3286 if (loopNode.hasPerIterationScope() && lc.getCurrentBlock().needsScope()) {
3287 // ES6 for loops with LET init need a new scope for each iteration. We just create a shallow copy here.
3288 method.loadCompilerConstant(SCOPE);
3289 method.invoke(virtualCallNoLookup(ScriptObject.class, "copy", ScriptObject.class));
3290 method.storeCompilerConstant(SCOPE);
3291 }
3292
3293 if(method.isReachable()) {
3294 if(modify != null) {
3295 lineNumber(loopNode);
3296 loadAndDiscard(modify);
3297 method.beforeJoinPoint(modify);
3298 }
3299 method._goto(repeatLabel);
3300 }
3301
3302 method.breakLabel(breakLabel, liveLocalsOnBreak);
3303 }
3304
3305 private void emitContinueLabel(final Label continueLabel, final int liveLocals) {
3306 final boolean reachable = method.isReachable();
3307 method.breakLabel(continueLabel, liveLocals);
3308 // If we reach here only through a continue statement (e.g. body does not exit normally) then the
3309 // continueLabel can have extra non-temp symbols (e.g. exception from a try/catch contained in the body). We
3310 // must make sure those are thrown away.
3311 if(!reachable) {
3312 method.undefineLocalVariables(lc.getUsedSlotCount(), false);
3313 }
3314 }
3315
3316 private void enterDoWhile(final WhileNode whileNode) {
3317 final int liveLocalsOnContinueOrBreak = method.getUsedSlotsWithLiveTemporaries();
3318 method.beforeJoinPoint(whileNode);
3319
3320 final Block body = whileNode.getBody();
3321 body.accept(this);
3322
3323 emitContinueLabel(whileNode.getContinueLabel(), liveLocalsOnContinueOrBreak);
3324 if(method.isReachable()) {
3325 lineNumber(whileNode);
3326 final JoinPredecessorExpression test = whileNode.getTest();
3327 final Label bodyEntryLabel = body.getEntryLabel();
3328 final boolean testHasLiveConversion = LocalVariableConversion.hasLiveConversion(test);
3329 if(Expression.isAlwaysFalse(test)) {
3330 loadAndDiscard(test);
3331 if(testHasLiveConversion) {
3332 method.beforeJoinPoint(test);
3333 }
3334 } else if(testHasLiveConversion) {
3335 // If we have conversions after the test in do-while, they need to be effected on both branches.
3336 final Label beforeExit = new Label("do_while_preexit");
3337 emitBranch(test.getExpression(), beforeExit, false);
3338 method.beforeJoinPoint(test);
3339 method._goto(bodyEntryLabel);
3340 method.label(beforeExit);
3341 method.beforeJoinPoint(test);
3342 } else {
3343 emitBranch(test.getExpression(), bodyEntryLabel, true);
3344 }
3345 }
3346 method.breakLabel(whileNode.getBreakLabel(), liveLocalsOnContinueOrBreak);
3347 }
3348
3349
3350 @Override
3351 public boolean enterWithNode(final WithNode withNode) {
3352 if(!method.isReachable()) {
3353 return false;
3354 }
3355 enterStatement(withNode);
3356 final Expression expression = withNode.getExpression();
3357 final Block body = withNode.getBody();
3358
3359 // It is possible to have a "pathological" case where the with block does not reference *any* identifiers. It's
3360 // pointless, but legal. In that case, if nothing else in the method forced the assignment of a slot to the
3361 // scope object, its' possible that it won't have a slot assigned. In this case we'll only evaluate expression
3362 // for its side effect and visit the body, and not bother opening and closing a WithObject.
3363 final boolean hasScope = method.hasScope();
3364
3365 if (hasScope) {
3366 method.loadCompilerConstant(SCOPE);
3367 }
3368
3369 loadExpressionAsObject(expression);
3370
3371 final Label tryLabel;
3372 if (hasScope) {
3373 // Construct a WithObject if we have a scope
3374 method.invoke(ScriptRuntime.OPEN_WITH);
3375 method.storeCompilerConstant(SCOPE);
3376 tryLabel = new Label("with_try");
3377 method.label(tryLabel);
3378 } else {
3379 // We just loaded the expression for its side effect and to check
3380 // for null or undefined value.
3381 globalCheckObjectCoercible();
3382 tryLabel = null;
3383 }
3384
3385 // Always process body
3386 body.accept(this);
3387
3388 if (hasScope) {
3389 // Ensure we always close the WithObject
3390 final Label endLabel = new Label("with_end");
3391 final Label catchLabel = new Label("with_catch");
3392 final Label exitLabel = new Label("with_exit");
3393
3394 method.label(endLabel);
3395 // Somewhat conservatively presume that if the body is not empty, it can throw an exception. In any case,
3396 // we must prevent trying to emit a try-catch for empty range, as it causes a verification error.
3397 final boolean bodyCanThrow = endLabel.isAfter(tryLabel);
3398 if(bodyCanThrow) {
3399 method._try(tryLabel, endLabel, catchLabel);
3400 }
3401
3402 final boolean reachable = method.isReachable();
3403 if(reachable) {
3404 popScope();
3405 if(bodyCanThrow) {
3406 method._goto(exitLabel);
3407 }
3408 }
3409
3410 if(bodyCanThrow) {
3411 method._catch(catchLabel);
3412 popScopeException();
3413 method.athrow();
3414 if(reachable) {
3415 method.label(exitLabel);
3416 }
3417 }
3418 }
3419 return false;
3420 }
3421
3422 private void loadADD(final UnaryNode unaryNode, final TypeBounds resultBounds) {
3423 loadExpression(unaryNode.getExpression(), resultBounds.booleanToInt().notWiderThan(Type.NUMBER));
3424 if(method.peekType() == Type.BOOLEAN) {
3425 // It's a no-op in bytecode, but we must make sure it is treated as an int for purposes of type signatures
3426 method.convert(Type.INT);
3427 }
3428 }
3429
3430 private void loadBIT_NOT(final UnaryNode unaryNode) {
3431 loadExpression(unaryNode.getExpression(), TypeBounds.INT).load(-1).xor();
3432 }
3433
3434 private void loadDECINC(final UnaryNode unaryNode) {
3435 final Expression operand = unaryNode.getExpression();
3436 final Type type = unaryNode.getType();
3437 final TypeBounds typeBounds = new TypeBounds(type, Type.NUMBER);
3438 final TokenType tokenType = unaryNode.tokenType();
3439 final boolean isPostfix = tokenType == TokenType.DECPOSTFIX || tokenType == TokenType.INCPOSTFIX;
3440 final boolean isIncrement = tokenType == TokenType.INCPREFIX || tokenType == TokenType.INCPOSTFIX;
3441
3442 assert !type.isObject();
3443
3444 new SelfModifyingStore<UnaryNode>(unaryNode, operand) {
3445
3446 private void loadRhs() {
3447 loadExpression(operand, typeBounds, true);
3448 }
3449
3450 @Override
3451 protected void evaluate() {
3452 if(isPostfix) {
3453 loadRhs();
3454 } else {
3455 new OptimisticOperation(unaryNode, typeBounds) {
3456 @Override
3457 void loadStack() {
3458 loadRhs();
3459 loadMinusOne();
3460 }
3461 @Override
3462 void consumeStack() {
3463 doDecInc(getProgramPoint());
3464 }
3465 }.emit(getOptimisticIgnoreCountForSelfModifyingExpression(operand));
3466 }
3467 }
3468
3469 @Override
3470 protected void storeNonDiscard() {
3471 super.storeNonDiscard();
3472 if (isPostfix) {
3473 new OptimisticOperation(unaryNode, typeBounds) {
3474 @Override
3475 void loadStack() {
3476 loadMinusOne();
3477 }
3478 @Override
3479 void consumeStack() {
3480 doDecInc(getProgramPoint());
3481 }
3482 }.emit(1); // 1 for non-incremented result on the top of the stack pushed in evaluate()
3483 }
3484 }
3485
3486 private void loadMinusOne() {
3487 if (type.isInteger()) {
3488 method.load(isIncrement ? 1 : -1);
3489 } else if (type.isLong()) {
3490 method.load(isIncrement ? 1L : -1L);
3491 } else {
3492 method.load(isIncrement ? 1.0 : -1.0);
3493 }
3494 }
3495
3496 private void doDecInc(final int programPoint) {
3497 method.add(programPoint);
3498 }
3499 }.store();
3500 }
3501
3502 private static int getOptimisticIgnoreCountForSelfModifyingExpression(final Expression target) {
3503 return target instanceof AccessNode ? 1 : target instanceof IndexNode ? 2 : 0;
3504 }
3505
3506 private void loadAndDiscard(final Expression expr) {
3507 // TODO: move checks for discarding to actual expression load code (e.g. as we do with void). That way we might
3508 // be able to eliminate even more checks.
3509 if(expr instanceof PrimitiveLiteralNode | isLocalVariable(expr)) {
3510 assert lc.getCurrentDiscard() != expr;
3511 // Don't bother evaluating expressions without side effects. Typical usage is "void 0" for reliably generating
3512 // undefined.
3513 return;
3514 }
3515
3516 lc.pushDiscard(expr);
3517 loadExpression(expr, TypeBounds.UNBOUNDED);
3518 if (lc.getCurrentDiscard() == expr) {
3519 assert !expr.isAssignment();
3520 // NOTE: if we had a way to load with type void, we could avoid popping
3521 method.pop();
3522 lc.popDiscard();
3523 }
3524 }
3525
3526 private void loadNEW(final UnaryNode unaryNode) {
3527 final CallNode callNode = (CallNode)unaryNode.getExpression();
3528 final List<Expression> args = callNode.getArgs();
3529
3530 // Load function reference.
3531 loadExpressionAsObject(callNode.getFunction()); // must detect type error
3532
3533 method.dynamicNew(1 + loadArgs(args), getCallSiteFlags());
3534 }
3535
3536 private void loadNOT(final UnaryNode unaryNode) {
3537 final Expression expr = unaryNode.getExpression();
3538 if(expr instanceof UnaryNode && expr.isTokenType(TokenType.NOT)) {
3539 // !!x is idiomatic boolean cast in JavaScript
3540 loadExpressionAsBoolean(((UnaryNode)expr).getExpression());
3541 } else {
3542 final Label trueLabel = new Label("true");
3543 final Label afterLabel = new Label("after");
3544
3545 emitBranch(expr, trueLabel, true);
3546 method.load(true);
3547 method._goto(afterLabel);
3548 method.label(trueLabel);
3549 method.load(false);
3550 method.label(afterLabel);
3551 }
3552 }
3553
3554 private void loadSUB(final UnaryNode unaryNode, final TypeBounds resultBounds) {
3555 final Type type = unaryNode.getType();
3556 assert type.isNumeric();
3557 final TypeBounds numericBounds = resultBounds.booleanToInt();
3558 new OptimisticOperation(unaryNode, numericBounds) {
3559 @Override
3560 void loadStack() {
3561 final Expression expr = unaryNode.getExpression();
3562 loadExpression(expr, numericBounds.notWiderThan(Type.NUMBER));
3563 }
3564 @Override
3565 void consumeStack() {
3566 // Must do an explicit conversion to the operation's type when it's double so that we correctly handle
3567 // negation of an int 0 to a double -0. With this, we get the correct negation of a local variable after
3568 // it deoptimized, e.g. "iload_2; i2d; dneg". Without this, we get "iload_2; ineg; i2d".
3569 if(type.isNumber()) {
3570 method.convert(type);
3571 }
3572 method.neg(getProgramPoint());
3573 }
3574 }.emit();
3575 }
3576
3577 public void loadVOID(final UnaryNode unaryNode, final TypeBounds resultBounds) {
3578 loadAndDiscard(unaryNode.getExpression());
3579 if(lc.getCurrentDiscard() == unaryNode) {
3580 lc.popDiscard();
3581 } else {
3582 method.loadUndefined(resultBounds.widest);
3583 }
3584 }
3585
3586 public void loadADD(final BinaryNode binaryNode, final TypeBounds resultBounds) {
3587 new OptimisticOperation(binaryNode, resultBounds) {
3588 @Override
3589 void loadStack() {
3590 final TypeBounds operandBounds;
3591 final boolean isOptimistic = isValid(getProgramPoint());
3592 boolean forceConversionSeparation = false;
3593 if(isOptimistic) {
3594 operandBounds = new TypeBounds(binaryNode.getType(), Type.OBJECT);
3595 } else {
3596 // Non-optimistic, non-FP +. Allow it to overflow.
3597 final Type widestOperationType = binaryNode.getWidestOperationType();
3598 operandBounds = new TypeBounds(Type.narrowest(binaryNode.getWidestOperandType(), resultBounds.widest), widestOperationType);
3599 forceConversionSeparation = widestOperationType.narrowerThan(resultBounds.widest);
3600 }
3601 loadBinaryOperands(binaryNode.lhs(), binaryNode.rhs(), operandBounds, false, forceConversionSeparation);
3602 }
3603
3604 @Override
3605 void consumeStack() {
3606 method.add(getProgramPoint());
3607 }
3608 }.emit();
3609 }
3610
3611 private void loadAND_OR(final BinaryNode binaryNode, final TypeBounds resultBounds, final boolean isAnd) {
3612 final Type narrowestOperandType = Type.widestReturnType(binaryNode.lhs().getType(), binaryNode.rhs().getType());
3613
3614 final Label skip = new Label("skip");
3615 if(narrowestOperandType == Type.BOOLEAN) {
3616 // optimize all-boolean logical expressions
3617 final Label onTrue = new Label("andor_true");
3618 emitBranch(binaryNode, onTrue, true);
3619 method.load(false);
3620 method._goto(skip);
3621 method.label(onTrue);
3622 method.load(true);
3623 method.label(skip);
3624 return;
3625 }
3626
3627 final TypeBounds outBounds = resultBounds.notNarrowerThan(narrowestOperandType);
3628 final JoinPredecessorExpression lhs = (JoinPredecessorExpression)binaryNode.lhs();
3629 final boolean lhsConvert = LocalVariableConversion.hasLiveConversion(lhs);
3630 final Label evalRhs = lhsConvert ? new Label("eval_rhs") : null;
3631
3632 loadExpression(lhs, outBounds).dup().convert(Type.BOOLEAN);
3633 if (isAnd) {
3634 if(lhsConvert) {
3635 method.ifne(evalRhs);
3636 } else {
3637 method.ifeq(skip);
3638 }
3639 } else if(lhsConvert) {
3640 method.ifeq(evalRhs);
3641 } else {
3642 method.ifne(skip);
3643 }
3644
3645 if(lhsConvert) {
3646 method.beforeJoinPoint(lhs);
3647 method._goto(skip);
3648 method.label(evalRhs);
3649 }
3650
3651 method.pop();
3652 final JoinPredecessorExpression rhs = (JoinPredecessorExpression)binaryNode.rhs();
3653 loadExpression(rhs, outBounds);
3654 method.beforeJoinPoint(rhs);
3655 method.label(skip);
3656 }
3657
3658 private static boolean isLocalVariable(final Expression lhs) {
3659 return lhs instanceof IdentNode && isLocalVariable((IdentNode)lhs);
3660 }
3661
3662 private static boolean isLocalVariable(final IdentNode lhs) {
3663 return lhs.getSymbol().isBytecodeLocal();
3664 }
3665
3666 // NOTE: does not use resultBounds as the assignment is driven by the type of the RHS
3667 private void loadASSIGN(final BinaryNode binaryNode) {
3668 final Expression lhs = binaryNode.lhs();
3669 final Expression rhs = binaryNode.rhs();
3670
3671 final Type rhsType = rhs.getType();
3672 // Detect dead assignments
3673 if(lhs instanceof IdentNode) {
3674 final Symbol symbol = ((IdentNode)lhs).getSymbol();
3675 if(!symbol.isScope() && !symbol.hasSlotFor(rhsType) && lc.getCurrentDiscard() == binaryNode) {
3676 loadAndDiscard(rhs);
3677 lc.popDiscard();
3678 method.markDeadLocalVariable(symbol);
3679 return;
3680 }
3681 }
3682
3683 new Store<BinaryNode>(binaryNode, lhs) {
3684 @Override
3685 protected void evaluate() {
3686 // NOTE: we're loading with "at least as wide as" so optimistic operations on the right hand side
3687 // remain optimistic, and then explicitly convert to the required type if needed.
3688 loadExpressionAsType(rhs, rhsType);
3689 }
3690 }.store();
3691 }
3692
3693 /**
3694 * Binary self-assignment that can be optimistic: +=, -=, *=, and /=.
3695 */
3696 private abstract class BinaryOptimisticSelfAssignment extends SelfModifyingStore<BinaryNode> {
3697
3698 /**
3699 * Constructor
3700 *
3701 * @param node the assign op node
3702 */
3703 BinaryOptimisticSelfAssignment(final BinaryNode node) {
3704 super(node, node.lhs());
3705 }
3706
3707 protected abstract void op(OptimisticOperation oo);
3708
3709 @Override
3710 protected void evaluate() {
3711 final Expression lhs = assignNode.lhs();
3712 final Expression rhs = assignNode.rhs();
3713 final Type widestOperationType = assignNode.getWidestOperationType();
3714 final TypeBounds bounds = new TypeBounds(assignNode.getType(), widestOperationType);
3715 new OptimisticOperation(assignNode, bounds) {
3716 @Override
3717 void loadStack() {
3718 final boolean forceConversionSeparation;
3719 if (isValid(getProgramPoint()) || widestOperationType == Type.NUMBER) {
3720 forceConversionSeparation = false;
3721 } else {
3722 final Type operandType = Type.widest(booleanToInt(objectToNumber(lhs.getType())), booleanToInt(objectToNumber(rhs.getType())));
3723 forceConversionSeparation = operandType.narrowerThan(widestOperationType);
3724 }
3725 loadBinaryOperands(lhs, rhs, bounds, true, forceConversionSeparation);
3726 }
3727 @Override
3728 void consumeStack() {
3729 op(this);
3730 }
3731 }.emit(getOptimisticIgnoreCountForSelfModifyingExpression(lhs));
3732 method.convert(assignNode.getType());
3733 }
3734 }
3735
3736 /**
3737 * Non-optimistic binary self-assignment operation. Basically, everything except +=, -=, *=, and /=.
3738 */
3739 private abstract class BinarySelfAssignment extends SelfModifyingStore<BinaryNode> {
3740 BinarySelfAssignment(final BinaryNode node) {
3741 super(node, node.lhs());
3742 }
3743
3744 protected abstract void op();
3745
3746 @Override
3747 protected void evaluate() {
3748 loadBinaryOperands(assignNode.lhs(), assignNode.rhs(), TypeBounds.UNBOUNDED.notWiderThan(assignNode.getWidestOperandType()), true, false);
3749 op();
3750 }
3751 }
3752
3753 private void loadASSIGN_ADD(final BinaryNode binaryNode) {
3754 new BinaryOptimisticSelfAssignment(binaryNode) {
3755 @Override
3756 protected void op(final OptimisticOperation oo) {
3757 assert !(binaryNode.getType().isObject() && oo.isOptimistic);
3758 method.add(oo.getProgramPoint());
3759 }
3760 }.store();
3761 }
3762
3763 private void loadASSIGN_BIT_AND(final BinaryNode binaryNode) {
3764 new BinarySelfAssignment(binaryNode) {
3765 @Override
3766 protected void op() {
3767 method.and();
3768 }
3769 }.store();
3770 }
3771
3772 private void loadASSIGN_BIT_OR(final BinaryNode binaryNode) {
3773 new BinarySelfAssignment(binaryNode) {
3774 @Override
3775 protected void op() {
3776 method.or();
3777 }
3778 }.store();
3779 }
3780
3781 private void loadASSIGN_BIT_XOR(final BinaryNode binaryNode) {
3782 new BinarySelfAssignment(binaryNode) {
3783 @Override
3784 protected void op() {
3785 method.xor();
3786 }
3787 }.store();
3788 }
3789
3790 private void loadASSIGN_DIV(final BinaryNode binaryNode) {
3791 new BinaryOptimisticSelfAssignment(binaryNode) {
3792 @Override
3793 protected void op(final OptimisticOperation oo) {
3794 method.div(oo.getProgramPoint());
3795 }
3796 }.store();
3797 }
3798
3799 private void loadASSIGN_MOD(final BinaryNode binaryNode) {
3800 new BinaryOptimisticSelfAssignment(binaryNode) {
3801 @Override
3802 protected void op(final OptimisticOperation oo) {
3803 method.rem(oo.getProgramPoint());
3804 }
3805 }.store();
3806 }
3807
3808 private void loadASSIGN_MUL(final BinaryNode binaryNode) {
3809 new BinaryOptimisticSelfAssignment(binaryNode) {
3810 @Override
3811 protected void op(final OptimisticOperation oo) {
3812 method.mul(oo.getProgramPoint());
3813 }
3814 }.store();
3815 }
3816
3817 private void loadASSIGN_SAR(final BinaryNode binaryNode) {
3818 new BinarySelfAssignment(binaryNode) {
3819 @Override
3820 protected void op() {
3821 method.sar();
3822 }
3823 }.store();
3824 }
3825
3826 private void loadASSIGN_SHL(final BinaryNode binaryNode) {
3827 new BinarySelfAssignment(binaryNode) {
3828 @Override
3829 protected void op() {
3830 method.shl();
3831 }
3832 }.store();
3833 }
3834
3835 private void loadASSIGN_SHR(final BinaryNode binaryNode) {
3836 new BinarySelfAssignment(binaryNode) {
3837 @Override
3838 protected void op() {
3839 doSHR();
3840 }
3841
3842 }.store();
3843 }
3844
3845 private void doSHR() {
3846 // TODO: make SHR optimistic
3847 method.shr();
3848 toUint();
3849 }
3850
3851 private void toUint() {
3852 JSType.TO_UINT32_I.invoke(method);
3853 }
3854
3855 private void loadASSIGN_SUB(final BinaryNode binaryNode) {
3856 new BinaryOptimisticSelfAssignment(binaryNode) {
3857 @Override
3858 protected void op(final OptimisticOperation oo) {
3859 method.sub(oo.getProgramPoint());
3860 }
3861 }.store();
3862 }
3863
3864 /**
3865 * Helper class for binary arithmetic ops
3866 */
3867 private abstract class BinaryArith {
3868 protected abstract void op(int programPoint);
3869
3870 protected void evaluate(final BinaryNode node, final TypeBounds resultBounds) {
3871 final TypeBounds numericBounds = resultBounds.booleanToInt().objectToNumber();
3872 new OptimisticOperation(node, numericBounds) {
3873 @Override
3874 void loadStack() {
3875 final TypeBounds operandBounds;
3876 boolean forceConversionSeparation = false;
3877 if(numericBounds.narrowest == Type.NUMBER) {
3878 // Result should be double always. Propagate it into the operands so we don't have lots of I2D
3879 // and L2D after operand evaluation.
3880 assert numericBounds.widest == Type.NUMBER;
3881 operandBounds = numericBounds;
3882 } else {
3883 final boolean isOptimistic = isValid(getProgramPoint());
3884 if(isOptimistic || node.isTokenType(TokenType.DIV) || node.isTokenType(TokenType.MOD)) {
3885 operandBounds = new TypeBounds(node.getType(), Type.NUMBER);
3886 } else {
3887 // Non-optimistic, non-FP subtraction or multiplication. Allow them to overflow.
3888 operandBounds = new TypeBounds(Type.narrowest(node.getWidestOperandType(),
3889 numericBounds.widest), Type.NUMBER);
3890 forceConversionSeparation = node.getWidestOperationType().narrowerThan(numericBounds.widest);
3891 }
3892 }
3893 loadBinaryOperands(node.lhs(), node.rhs(), operandBounds, false, forceConversionSeparation);
3894 }
3895
3896 @Override
3897 void consumeStack() {
3898 op(getProgramPoint());
3899 }
3900 }.emit();
3901 }
3902 }
3903
3904 private void loadBIT_AND(final BinaryNode binaryNode) {
3905 loadBinaryOperands(binaryNode);
3906 method.and();
3907 }
3908
3909 private void loadBIT_OR(final BinaryNode binaryNode) {
3910 // Optimize x|0 to (int)x
3911 if (isRhsZero(binaryNode)) {
3912 loadExpressionAsType(binaryNode.lhs(), Type.INT);
3913 } else {
3914 loadBinaryOperands(binaryNode);
3915 method.or();
3916 }
3917 }
3918
3919 private static boolean isRhsZero(final BinaryNode binaryNode) {
3920 final Expression rhs = binaryNode.rhs();
3921 return rhs instanceof LiteralNode && INT_ZERO.equals(((LiteralNode<?>)rhs).getValue());
3922 }
3923
3924 private void loadBIT_XOR(final BinaryNode binaryNode) {
3925 loadBinaryOperands(binaryNode);
3926 method.xor();
3927 }
3928
3929 private void loadCOMMARIGHT(final BinaryNode binaryNode, final TypeBounds resultBounds) {
3930 loadAndDiscard(binaryNode.lhs());
3931 loadExpression(binaryNode.rhs(), resultBounds);
3932 }
3933
3934 private void loadCOMMALEFT(final BinaryNode binaryNode, final TypeBounds resultBounds) {
3935 loadExpression(binaryNode.lhs(), resultBounds);
3936 loadAndDiscard(binaryNode.rhs());
3937 }
3938
3939 private void loadDIV(final BinaryNode binaryNode, final TypeBounds resultBounds) {
3940 new BinaryArith() {
3941 @Override
3942 protected void op(final int programPoint) {
3943 method.div(programPoint);
3944 }
3945 }.evaluate(binaryNode, resultBounds);
3946 }
3947
3948 private void loadCmp(final BinaryNode binaryNode, final Condition cond) {
3949 assert comparisonOperandsArePrimitive(binaryNode) : binaryNode;
3950 loadBinaryOperands(binaryNode);
3951
3952 final Label trueLabel = new Label("trueLabel");
3953 final Label afterLabel = new Label("skip");
3954
3955 method.conditionalJump(cond, trueLabel);
3956
3957 method.load(Boolean.FALSE);
3958 method._goto(afterLabel);
3959 method.label(trueLabel);
3960 method.load(Boolean.TRUE);
3961 method.label(afterLabel);
3962 }
3963
3964 private static boolean comparisonOperandsArePrimitive(final BinaryNode binaryNode) {
3965 final Type widest = Type.widest(binaryNode.lhs().getType(), binaryNode.rhs().getType());
3966 return widest.isNumeric() || widest.isBoolean();
3967 }
3968
3969 private void loadMOD(final BinaryNode binaryNode, final TypeBounds resultBounds) {
3970 new BinaryArith() {
3971 @Override
3972 protected void op(final int programPoint) {
3973 method.rem(programPoint);
3974 }
3975 }.evaluate(binaryNode, resultBounds);
3976 }
3977
3978 private void loadMUL(final BinaryNode binaryNode, final TypeBounds resultBounds) {
3979 new BinaryArith() {
3980 @Override
3981 protected void op(final int programPoint) {
3982 method.mul(programPoint);
3983 }
3984 }.evaluate(binaryNode, resultBounds);
3985 }
3986
3987 private void loadSAR(final BinaryNode binaryNode) {
3988 loadBinaryOperands(binaryNode);
3989 method.sar();
3990 }
3991
3992 private void loadSHL(final BinaryNode binaryNode) {
3993 loadBinaryOperands(binaryNode);
3994 method.shl();
3995 }
3996
3997 private void loadSHR(final BinaryNode binaryNode) {
3998 // Optimize x >>> 0 to (uint)x
3999 if (isRhsZero(binaryNode)) {
4000 loadExpressionAsType(binaryNode.lhs(), Type.INT);
4001 toUint();
4002 } else {
4003 loadBinaryOperands(binaryNode);
4004 doSHR();
4005 }
4006 }
4007
4008 private void loadSUB(final BinaryNode binaryNode, final TypeBounds resultBounds) {
4009 new BinaryArith() {
4010 @Override
4011 protected void op(final int programPoint) {
4012 method.sub(programPoint);
4013 }
4014 }.evaluate(binaryNode, resultBounds);
4015 }
4016
4017 @Override
4018 public boolean enterLabelNode(final LabelNode labelNode) {
4019 labeledBlockBreakLiveLocals.push(lc.getUsedSlotCount());
4020 return true;
4021 }
4022
4023 @Override
4024 protected boolean enterDefault(final Node node) {
4025 throw new AssertionError("Code generator entered node of type " + node.getClass().getName());
4026 }
4027
4028 private void loadTernaryNode(final TernaryNode ternaryNode, final TypeBounds resultBounds) {
4029 final Expression test = ternaryNode.getTest();
4030 final JoinPredecessorExpression trueExpr = ternaryNode.getTrueExpression();
4031 final JoinPredecessorExpression falseExpr = ternaryNode.getFalseExpression();
4032
4033 final Label falseLabel = new Label("ternary_false");
4034 final Label exitLabel = new Label("ternary_exit");
4035
4036 final Type outNarrowest = Type.narrowest(resultBounds.widest, Type.generic(Type.widestReturnType(trueExpr.getType(), falseExpr.getType())));
4037 final TypeBounds outBounds = resultBounds.notNarrowerThan(outNarrowest);
4038
4039 emitBranch(test, falseLabel, false);
4040
4041 loadExpression(trueExpr.getExpression(), outBounds);
4042 assert Type.generic(method.peekType()) == outBounds.narrowest;
4043 method.beforeJoinPoint(trueExpr);
4044 method._goto(exitLabel);
4045 method.label(falseLabel);
4046 loadExpression(falseExpr.getExpression(), outBounds);
4047 assert Type.generic(method.peekType()) == outBounds.narrowest;
4048 method.beforeJoinPoint(falseExpr);
4049 method.label(exitLabel);
4050 }
4051
4052 /**
4053 * Generate all shared scope calls generated during codegen.
4054 */
4055 void generateScopeCalls() {
4056 for (final SharedScopeCall scopeAccess : lc.getScopeCalls()) {
4057 scopeAccess.generateScopeCall();
4058 }
4059 }
4060
4061 /**
4062 * Debug code used to print symbols
4063 *
4064 * @param block the block we are in
4065 * @param function the function we are in
4066 * @param ident identifier for block or function where applicable
4067 */
4068 private void printSymbols(final Block block, final FunctionNode function, final String ident) {
4069 if (compiler.getScriptEnvironment()._print_symbols || function.getFlag(FunctionNode.IS_PRINT_SYMBOLS)) {
4070 final PrintWriter out = compiler.getScriptEnvironment().getErr();
4071 out.println("[BLOCK in '" + ident + "']");
4072 if (!block.printSymbols(out)) {
4073 out.println("<no symbols>");
4074 }
4075 out.println();
4076 }
4077 }
4078
4079
4080 /**
4081 * The difference between a store and a self modifying store is that
4082 * the latter may load part of the target on the stack, e.g. the base
4083 * of an AccessNode or the base and index of an IndexNode. These are used
4084 * both as target and as an extra source. Previously it was problematic
4085 * for self modifying stores if the target/lhs didn't belong to one
4086 * of three trivial categories: IdentNode, AcessNodes, IndexNodes. In that
4087 * case it was evaluated and tagged as "resolved", which meant at the second
4088 * time the lhs of this store was read (e.g. in a = a (second) + b for a += b,
4089 * it would be evaluated to a nop in the scope and cause stack underflow
4090 *
4091 * see NASHORN-703
4092 *
4093 * @param <T>
4094 */
4095 private abstract class SelfModifyingStore<T extends Expression> extends Store<T> {
4096 protected SelfModifyingStore(final T assignNode, final Expression target) {
4097 super(assignNode, target);
4098 }
4099
4100 @Override
4101 protected boolean isSelfModifying() {
4102 return true;
4103 }
4104 }
4105
4106 /**
4107 * Helper class to generate stores
4108 */
4109 private abstract class Store<T extends Expression> {
4110
4111 /** An assignment node, e.g. x += y */
4112 protected final T assignNode;
4113
4114 /** The target node to store to, e.g. x */
4115 private final Expression target;
4116
4117 /** How deep on the stack do the arguments go if this generates an indy call */
4118 private int depth;
4119
4120 /** If we have too many arguments, we need temporary storage, this is stored in 'quick' */
4121 private IdentNode quick;
4122
4123 /**
4124 * Constructor
4125 *
4126 * @param assignNode the node representing the whole assignment
4127 * @param target the target node of the assignment (destination)
4128 */
4129 protected Store(final T assignNode, final Expression target) {
4130 this.assignNode = assignNode;
4131 this.target = target;
4132 }
4133
4134 /**
4135 * Constructor
4136 *
4137 * @param assignNode the node representing the whole assignment
4138 */
4139 protected Store(final T assignNode) {
4140 this(assignNode, assignNode);
4141 }
4142
4143 /**
4144 * Is this a self modifying store operation, e.g. *= or ++
4145 * @return true if self modifying store
4146 */
4147 protected boolean isSelfModifying() {
4148 return false;
4149 }
4150
4151 private void prologue() {
4152 /**
4153 * This loads the parts of the target, e.g base and index. they are kept
4154 * on the stack throughout the store and used at the end to execute it
4155 */
4156
4157 target.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) {
4158 @Override
4159 public boolean enterIdentNode(final IdentNode node) {
4160 if (node.getSymbol().isScope()) {
4161 method.loadCompilerConstant(SCOPE);
4162 depth += Type.SCOPE.getSlots();
4163 assert depth == 1;
4164 }
4165 return false;
4166 }
4167
4168 private void enterBaseNode() {
4169 assert target instanceof BaseNode : "error - base node " + target + " must be instanceof BaseNode";
4170 final BaseNode baseNode = (BaseNode)target;
4171 final Expression base = baseNode.getBase();
4172
4173 loadExpressionAsObject(base);
4174 depth += Type.OBJECT.getSlots();
4175 assert depth == 1;
4176
4177 if (isSelfModifying()) {
4178 method.dup();
4179 }
4180 }
4181
4182 @Override
4183 public boolean enterAccessNode(final AccessNode node) {
4184 enterBaseNode();
4185 return false;
4186 }
4187
4188 @Override
4189 public boolean enterIndexNode(final IndexNode node) {
4190 enterBaseNode();
4191
4192 final Expression index = node.getIndex();
4193 if (!index.getType().isNumeric()) {
4194 // could be boolean here as well
4195 loadExpressionAsObject(index);
4196 } else {
4197 loadExpressionUnbounded(index);
4198 }
4199 depth += index.getType().getSlots();
4200
4201 if (isSelfModifying()) {
4202 //convert "base base index" to "base index base index"
4203 method.dup(1);
4204 }
4205
4206 return false;
4207 }
4208
4209 });
4210 }
4211
4212 /**
4213 * Generates an extra local variable, always using the same slot, one that is available after the end of the
4214 * frame.
4215 *
4216 * @param type the type of the variable
4217 *
4218 * @return the quick variable
4219 */
4220 private IdentNode quickLocalVariable(final Type type) {
4221 final String name = lc.getCurrentFunction().uniqueName(QUICK_PREFIX.symbolName());
4222 final Symbol symbol = new Symbol(name, IS_INTERNAL | HAS_SLOT);
4223 symbol.setHasSlotFor(type);
4224 symbol.setFirstSlot(lc.quickSlot(type));
4225
4226 final IdentNode quickIdent = IdentNode.createInternalIdentifier(symbol).setType(type);
4227
4228 return quickIdent;
4229 }
4230
4231 // store the result that "lives on" after the op, e.g. "i" in i++ postfix.
4232 protected void storeNonDiscard() {
4233 if (lc.getCurrentDiscard() == assignNode) {
4234 assert assignNode.isAssignment();
4235 lc.popDiscard();
4236 return;
4237 }
4238
4239 if (method.dup(depth) == null) {
4240 method.dup();
4241 final Type quickType = method.peekType();
4242 this.quick = quickLocalVariable(quickType);
4243 final Symbol quickSymbol = quick.getSymbol();
4244 method.storeTemp(quickType, quickSymbol.getFirstSlot());
4245 }
4246 }
4247
4248 private void epilogue() {
4249 /**
4250 * Take the original target args from the stack and use them
4251 * together with the value to be stored to emit the store code
4252 *
4253 * The case that targetSymbol is in scope (!hasSlot) and we actually
4254 * need to do a conversion on non-equivalent types exists, but is
4255 * very rare. See for example test/script/basic/access-specializer.js
4256 */
4257 target.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) {
4258 @Override
4259 protected boolean enterDefault(final Node node) {
4260 throw new AssertionError("Unexpected node " + node + " in store epilogue");
4261 }
4262
4263 @Override
4264 public boolean enterIdentNode(final IdentNode node) {
4265 final Symbol symbol = node.getSymbol();
4266 assert symbol != null;
4267 if (symbol.isScope()) {
4268 final int flags = CALLSITE_SCOPE | getCallSiteFlags();
4269 if (isFastScope(symbol)) {
4270 storeFastScopeVar(symbol, flags);
4271 } else {
4272 method.dynamicSet(node.getName(), flags, false);
4273 }
4274 } else {
4275 final Type storeType = assignNode.getType();
4276 if (symbol.hasSlotFor(storeType)) {
4277 // Only emit a convert for a store known to be live; converts for dead stores can
4278 // give us an unnecessary ClassCastException.
4279 method.convert(storeType);
4280 }
4281 storeIdentWithCatchConversion(node, storeType);
4282 }
4283 return false;
4284
4285 }
4286
4287 @Override
4288 public boolean enterAccessNode(final AccessNode node) {
4289 method.dynamicSet(node.getProperty(), getCallSiteFlags(), node.isIndex());
4290 return false;
4291 }
4292
4293 @Override
4294 public boolean enterIndexNode(final IndexNode node) {
4295 method.dynamicSetIndex(getCallSiteFlags());
4296 return false;
4297 }
4298 });
4299
4300
4301 // whatever is on the stack now is the final answer
4302 }
4303
4304 protected abstract void evaluate();
4305
4306 void store() {
4307 if (target instanceof IdentNode) {
4308 checkTemporalDeadZone((IdentNode)target);
4309 }
4310 prologue();
4311 evaluate(); // leaves an operation of whatever the operationType was on the stack
4312 storeNonDiscard();
4313 epilogue();
4314 if (quick != null) {
4315 method.load(quick);
4316 }
4317 }
4318 }
4319
4320 private void newFunctionObject(final FunctionNode functionNode, final boolean addInitializer) {
4321 assert lc.peek() == functionNode;
4322
4323 final RecompilableScriptFunctionData data = compiler.getScriptFunctionData(functionNode.getId());
4324
4325 if (functionNode.isProgram() && !compiler.isOnDemandCompilation()) {
4326 final CompileUnit fnUnit = functionNode.getCompileUnit();
4327 final MethodEmitter createFunction = fnUnit.getClassEmitter().method(
4328 EnumSet.of(Flag.PUBLIC, Flag.STATIC), CREATE_PROGRAM_FUNCTION.symbolName(),
4329 ScriptFunction.class, ScriptObject.class);
4330 createFunction.begin();
4331 createFunction._new(SCRIPTFUNCTION_IMPL_NAME, SCRIPTFUNCTION_IMPL_TYPE).dup();
4332 loadConstant(data, fnUnit, createFunction);
4333 createFunction.load(SCOPE_TYPE, 0);
4334 createFunction.invoke(constructorNoLookup(SCRIPTFUNCTION_IMPL_NAME, RecompilableScriptFunctionData.class, ScriptObject.class));
4335 createFunction._return();
4336 createFunction.end();
4337 }
4338
4339 if (addInitializer && !compiler.isOnDemandCompilation()) {
4340 compiler.addFunctionInitializer(data, functionNode);
4341 }
4342
4343 // We don't emit a ScriptFunction on stack for the outermost compiled function (as there's no code being
4344 // generated in its outer context that'd need it as a callee).
4345 if (lc.getOutermostFunction() == functionNode) {
4346 return;
4347 }
4348
4349 method._new(SCRIPTFUNCTION_IMPL_NAME, SCRIPTFUNCTION_IMPL_TYPE).dup();
4350 loadConstant(data);
4351
4352 if (functionNode.needsParentScope()) {
4353 method.loadCompilerConstant(SCOPE);
4354 } else {
4355 method.loadNull();
4356 }
4357 method.invoke(constructorNoLookup(SCRIPTFUNCTION_IMPL_NAME, RecompilableScriptFunctionData.class, ScriptObject.class));
4358 }
4359
4360 // calls on Global class.
4361 private MethodEmitter globalInstance() {
4362 return method.invokestatic(GLOBAL_OBJECT, "instance", "()L" + GLOBAL_OBJECT + ';');
4363 }
4364
4365 private MethodEmitter globalAllocateArguments() {
4366 return method.invokestatic(GLOBAL_OBJECT, "allocateArguments", methodDescriptor(ScriptObject.class, Object[].class, Object.class, int.class));
4367 }
4368
4369 private MethodEmitter globalNewRegExp() {
4370 return method.invokestatic(GLOBAL_OBJECT, "newRegExp", methodDescriptor(Object.class, String.class, String.class));
4371 }
4372
4373 private MethodEmitter globalRegExpCopy() {
4374 return method.invokestatic(GLOBAL_OBJECT, "regExpCopy", methodDescriptor(Object.class, Object.class));
4375 }
4376
4377 private MethodEmitter globalAllocateArray(final ArrayType type) {
4378 //make sure the native array is treated as an array type
4379 return method.invokestatic(GLOBAL_OBJECT, "allocate", "(" + type.getDescriptor() + ")Ljdk/nashorn/internal/objects/NativeArray;");
4380 }
4381
4382 private MethodEmitter globalIsEval() {
4383 return method.invokestatic(GLOBAL_OBJECT, "isEval", methodDescriptor(boolean.class, Object.class));
4384 }
4385
4386 private MethodEmitter globalReplaceLocationPropertyPlaceholder() {
4387 return method.invokestatic(GLOBAL_OBJECT, "replaceLocationPropertyPlaceholder", methodDescriptor(Object.class, Object.class, Object.class));
4388 }
4389
4390 private MethodEmitter globalCheckObjectCoercible() {
4391 return method.invokestatic(GLOBAL_OBJECT, "checkObjectCoercible", methodDescriptor(void.class, Object.class));
4392 }
4393
4394 private MethodEmitter globalDirectEval() {
4395 return method.invokestatic(GLOBAL_OBJECT, "directEval",
4396 methodDescriptor(Object.class, Object.class, Object.class, Object.class, Object.class, boolean.class));
4397 }
4398
4399 private abstract class OptimisticOperation {
4400 private final boolean isOptimistic;
4401 // expression and optimistic are the same reference
4402 private final Expression expression;
4403 private final Optimistic optimistic;
4404 private final TypeBounds resultBounds;
4405
4406 OptimisticOperation(final Optimistic optimistic, final TypeBounds resultBounds) {
4407 this.optimistic = optimistic;
4408 this.expression = (Expression)optimistic;
4409 this.resultBounds = resultBounds;
4410 this.isOptimistic = isOptimistic(optimistic) && useOptimisticTypes() &&
4411 // Operation is only effectively optimistic if its type, after being coerced into the result bounds
4412 // is narrower than the upper bound.
4413 resultBounds.within(Type.generic(((Expression)optimistic).getType())).narrowerThan(resultBounds.widest);
4414 }
4415
4416 MethodEmitter emit() {
4417 return emit(0);
4418 }
4419
4420 MethodEmitter emit(final int ignoredArgCount) {
4421 final int programPoint = optimistic.getProgramPoint();
4422 final boolean optimisticOrContinuation = isOptimistic || isContinuationEntryPoint(programPoint);
4423 final boolean currentContinuationEntryPoint = isCurrentContinuationEntryPoint(programPoint);
4424 final int stackSizeOnEntry = method.getStackSize() - ignoredArgCount;
4425
4426 // First store the values on the stack opportunistically into local variables. Doing it before loadStack()
4427 // allows us to not have to pop/load any arguments that are pushed onto it by loadStack() in the second
4428 // storeStack().
4429 storeStack(ignoredArgCount, optimisticOrContinuation);
4430
4431 // Now, load the stack
4432 loadStack();
4433
4434 // Now store the values on the stack ultimately into local variables. In vast majority of cases, this is
4435 // (aside from creating the local types map) a no-op, as the first opportunistic stack store will already
4436 // store all variables. However, there can be operations in the loadStack() that invalidate some of the
4437 // stack stores, e.g. in "x[i] = x[++i]", "++i" will invalidate the already stored value for "i". In such
4438 // unfortunate cases this second storeStack() will restore the invariant that everything on the stack is
4439 // stored into a local variable, although at the cost of doing a store/load on the loaded arguments as well.
4440 final int liveLocalsCount = storeStack(method.getStackSize() - stackSizeOnEntry, optimisticOrContinuation);
4441 assert optimisticOrContinuation == (liveLocalsCount != -1);
4442
4443 final Label beginTry;
4444 final Label catchLabel;
4445 final Label afterConsumeStack = isOptimistic || currentContinuationEntryPoint ? new Label("after_consume_stack") : null;
4446 if(isOptimistic) {
4447 beginTry = new Label("try_optimistic");
4448 final String catchLabelName = (afterConsumeStack == null ? "" : afterConsumeStack.toString()) + "_handler";
4449 catchLabel = new Label(catchLabelName);
4450 method.label(beginTry);
4451 } else {
4452 beginTry = catchLabel = null;
4453 }
4454
4455 consumeStack();
4456
4457 if(isOptimistic) {
4458 method._try(beginTry, afterConsumeStack, catchLabel, UnwarrantedOptimismException.class);
4459 }
4460
4461 if(isOptimistic || currentContinuationEntryPoint) {
4462 method.label(afterConsumeStack);
4463
4464 final int[] localLoads = method.getLocalLoadsOnStack(0, stackSizeOnEntry);
4465 assert everyStackValueIsLocalLoad(localLoads) : Arrays.toString(localLoads) + ", " + stackSizeOnEntry + ", " + ignoredArgCount;
4466 final List<Type> localTypesList = method.getLocalVariableTypes();
4467 final int usedLocals = method.getUsedSlotsWithLiveTemporaries();
4468 final List<Type> localTypes = method.getWidestLiveLocals(localTypesList.subList(0, usedLocals));
4469 assert everyLocalLoadIsValid(localLoads, usedLocals) : Arrays.toString(localLoads) + " ~ " + localTypes;
4470
4471 if(isOptimistic) {
4472 addUnwarrantedOptimismHandlerLabel(localTypes, catchLabel);
4473 }
4474 if(currentContinuationEntryPoint) {
4475 final ContinuationInfo ci = getContinuationInfo();
4476 assert ci != null : "no continuation info found for " + lc.getCurrentFunction();
4477 assert !ci.hasTargetLabel(); // No duplicate program points
4478 ci.setTargetLabel(afterConsumeStack);
4479 ci.getHandlerLabel().markAsOptimisticContinuationHandlerFor(afterConsumeStack);
4480 // Can't rely on targetLabel.stack.localVariableTypes.length, as it can be higher due to effectively
4481 // dead local variables.
4482 ci.lvarCount = localTypes.size();
4483 ci.setStackStoreSpec(localLoads);
4484 ci.setStackTypes(Arrays.copyOf(method.getTypesFromStack(method.getStackSize()), stackSizeOnEntry));
4485 assert ci.getStackStoreSpec().length == ci.getStackTypes().length;
4486 ci.setReturnValueType(method.peekType());
4487 ci.lineNumber = getLastLineNumber();
4488 ci.catchLabel = catchLabels.peek();
4489 }
4490 }
4491 return method;
4492 }
4493
4494 /**
4495 * Stores the current contents of the stack into local variables so they are not lost before invoking something that
4496 * can result in an {@code UnwarantedOptimizationException}.
4497 * @param ignoreArgCount the number of topmost arguments on stack to ignore when deciding on the shape of the catch
4498 * block. Those are used in the situations when we could not place the call to {@code storeStack} early enough
4499 * (before emitting code for pushing the arguments that the optimistic call will pop). This is admittedly a
4500 * deficiency in the design of the code generator when it deals with self-assignments and we should probably look
4501 * into fixing it.
4502 * @return types of the significant local variables after the stack was stored (types for local variables used
4503 * for temporary storage of ignored arguments are not returned).
4504 * @param optimisticOrContinuation if false, this method should not execute
4505 * a label for a catch block for the {@code UnwarantedOptimizationException}, suitable for capturing the
4506 * currently live local variables, tailored to their types.
4507 */
4508 private int storeStack(final int ignoreArgCount, final boolean optimisticOrContinuation) {
4509 if(!optimisticOrContinuation) {
4510 return -1; // NOTE: correct value to return is lc.getUsedSlotCount(), but it wouldn't be used anyway
4511 }
4512
4513 final int stackSize = method.getStackSize();
4514 final Type[] stackTypes = method.getTypesFromStack(stackSize);
4515 final int[] localLoadsOnStack = method.getLocalLoadsOnStack(0, stackSize);
4516 final int usedSlots = method.getUsedSlotsWithLiveTemporaries();
4517
4518 final int firstIgnored = stackSize - ignoreArgCount;
4519 // Find the first value on the stack (from the bottom) that is not a load from a local variable.
4520 int firstNonLoad = 0;
4521 while(firstNonLoad < firstIgnored && localLoadsOnStack[firstNonLoad] != Label.Stack.NON_LOAD) {
4522 firstNonLoad++;
4523 }
4524
4525 // Only do the store/load if first non-load is not an ignored argument. Otherwise, do nothing and return
4526 // the number of used slots as the number of live local variables.
4527 if(firstNonLoad >= firstIgnored) {
4528 return usedSlots;
4529 }
4530
4531 // Find the number of new temporary local variables that we need; it's the number of values on the stack that
4532 // are not direct loads of existing local variables.
4533 int tempSlotsNeeded = 0;
4534 for(int i = firstNonLoad; i < stackSize; ++i) {
4535 if(localLoadsOnStack[i] == Label.Stack.NON_LOAD) {
4536 tempSlotsNeeded += stackTypes[i].getSlots();
4537 }
4538 }
4539
4540 // Ensure all values on the stack that weren't directly loaded from a local variable are stored in a local
4541 // variable. We're starting from highest local variable index, so that in case ignoreArgCount > 0 the ignored
4542 // ones end up at the end of the local variable table.
4543 int lastTempSlot = usedSlots + tempSlotsNeeded;
4544 int ignoreSlotCount = 0;
4545 for(int i = stackSize; i -- > firstNonLoad;) {
4546 final int loadSlot = localLoadsOnStack[i];
4547 if(loadSlot == Label.Stack.NON_LOAD) {
4548 final Type type = stackTypes[i];
4549 final int slots = type.getSlots();
4550 lastTempSlot -= slots;
4551 if(i >= firstIgnored) {
4552 ignoreSlotCount += slots;
4553 }
4554 method.storeTemp(type, lastTempSlot);
4555 } else {
4556 method.pop();
4557 }
4558 }
4559 assert lastTempSlot == usedSlots; // used all temporary locals
4560
4561 final List<Type> localTypesList = method.getLocalVariableTypes();
4562
4563 // Load values back on stack.
4564 for(int i = firstNonLoad; i < stackSize; ++i) {
4565 final int loadSlot = localLoadsOnStack[i];
4566 final Type stackType = stackTypes[i];
4567 final boolean isLoad = loadSlot != Label.Stack.NON_LOAD;
4568 final int lvarSlot = isLoad ? loadSlot : lastTempSlot;
4569 final Type lvarType = localTypesList.get(lvarSlot);
4570 method.load(lvarType, lvarSlot);
4571 if(isLoad) {
4572 // Conversion operators (I2L etc.) preserve "load"-ness of the value despite the fact that, in the
4573 // strict sense they are creating a derived value from the loaded value. This special behavior of
4574 // on-stack conversion operators is necessary to accommodate for differences in local variable types
4575 // after deoptimization; having a conversion operator throw away "load"-ness would create different
4576 // local variable table shapes between optimism-failed code and its deoptimized rest-of method).
4577 // After we load the value back, we need to redo the conversion to the stack type if stack type is
4578 // different.
4579 // NOTE: this would only strictly be necessary for widening conversions (I2L, L2D, I2D), and not for
4580 // narrowing ones (L2I, D2L, D2I) as only widening conversions are the ones that can get eliminated
4581 // in a deoptimized method, as their original input argument got widened. Maybe experiment with
4582 // throwing away "load"-ness for narrowing conversions in MethodEmitter.convert()?
4583 method.convert(stackType);
4584 } else {
4585 // temporary stores never needs a convert, as their type is always the same as the stack type.
4586 assert lvarType == stackType;
4587 lastTempSlot += lvarType.getSlots();
4588 }
4589 }
4590 // used all temporaries
4591 assert lastTempSlot == usedSlots + tempSlotsNeeded;
4592
4593 return lastTempSlot - ignoreSlotCount;
4594 }
4595
4596 private void addUnwarrantedOptimismHandlerLabel(final List<Type> localTypes, final Label label) {
4597 final String lvarTypesDescriptor = getLvarTypesDescriptor(localTypes);
4598 final Map<String, Collection<Label>> unwarrantedOptimismHandlers = lc.getUnwarrantedOptimismHandlers();
4599 Collection<Label> labels = unwarrantedOptimismHandlers.get(lvarTypesDescriptor);
4600 if(labels == null) {
4601 labels = new LinkedList<>();
4602 unwarrantedOptimismHandlers.put(lvarTypesDescriptor, labels);
4603 }
4604 method.markLabelAsOptimisticCatchHandler(label, localTypes.size());
4605 labels.add(label);
4606 }
4607
4608 abstract void loadStack();
4609
4610 // Make sure that whatever indy call site you emit from this method uses {@code getCallSiteFlagsOptimistic(node)}
4611 // or otherwise ensure optimistic flag is correctly set in the call site, otherwise it doesn't make much sense
4612 // to use OptimisticExpression for emitting it.
4613 abstract void consumeStack();
4614
4615 /**
4616 * Emits the correct dynamic getter code. Normally just delegates to method emitter, except when the target
4617 * expression is optimistic, and the desired type is narrower than the optimistic type. In that case, it'll emit a
4618 * dynamic getter with its original optimistic type, and explicitly insert a narrowing conversion. This way we can
4619 * preserve the optimism of the values even if they're subsequently immediately coerced into a narrower type. This
4620 * is beneficial because in this case we can still presume that since the original getter was optimistic, the
4621 * conversion has no side effects.
4622 * @param name the name of the property being get
4623 * @param flags call site flags
4624 * @param isMethod whether we're preferrably retrieving a function
4625 * @return the current method emitter
4626 */
4627 MethodEmitter dynamicGet(final String name, final int flags, final boolean isMethod, final boolean isIndex) {
4628 if(isOptimistic) {
4629 return method.dynamicGet(getOptimisticCoercedType(), name, getOptimisticFlags(flags), isMethod, isIndex);
4630 }
4631 return method.dynamicGet(resultBounds.within(expression.getType()), name, nonOptimisticFlags(flags), isMethod, isIndex);
4632 }
4633
4634 MethodEmitter dynamicGetIndex(final int flags, final boolean isMethod) {
4635 if(isOptimistic) {
4636 return method.dynamicGetIndex(getOptimisticCoercedType(), getOptimisticFlags(flags), isMethod);
4637 }
4638 return method.dynamicGetIndex(resultBounds.within(expression.getType()), nonOptimisticFlags(flags), isMethod);
4639 }
4640
4641 MethodEmitter dynamicCall(final int argCount, final int flags) {
4642 if (isOptimistic) {
4643 return method.dynamicCall(getOptimisticCoercedType(), argCount, getOptimisticFlags(flags));
4644 }
4645 return method.dynamicCall(resultBounds.within(expression.getType()), argCount, nonOptimisticFlags(flags));
4646 }
4647
4648 int getOptimisticFlags(final int flags) {
4649 return flags | CALLSITE_OPTIMISTIC | (optimistic.getProgramPoint() << CALLSITE_PROGRAM_POINT_SHIFT); //encode program point in high bits
4650 }
4651
4652 int getProgramPoint() {
4653 return isOptimistic ? optimistic.getProgramPoint() : INVALID_PROGRAM_POINT;
4654 }
4655
4656 void convertOptimisticReturnValue() {
4657 if (isOptimistic) {
4658 final Type optimisticType = getOptimisticCoercedType();
4659 if(!optimisticType.isObject()) {
4660 method.load(optimistic.getProgramPoint());
4661 if(optimisticType.isInteger()) {
4662 method.invoke(ENSURE_INT);
4663 } else if(optimisticType.isLong()) {
4664 method.invoke(ENSURE_LONG);
4665 } else if(optimisticType.isNumber()) {
4666 method.invoke(ENSURE_NUMBER);
4667 } else {
4668 throw new AssertionError(optimisticType);
4669 }
4670 }
4671 }
4672 }
4673
4674 void replaceCompileTimeProperty() {
4675 final IdentNode identNode = (IdentNode)expression;
4676 final String name = identNode.getSymbol().getName();
4677 if (CompilerConstants.__FILE__.name().equals(name)) {
4678 replaceCompileTimeProperty(getCurrentSource().getName());
4679 } else if (CompilerConstants.__DIR__.name().equals(name)) {
4680 replaceCompileTimeProperty(getCurrentSource().getBase());
4681 } else if (CompilerConstants.__LINE__.name().equals(name)) {
4682 replaceCompileTimeProperty(getCurrentSource().getLine(identNode.position()));
4683 }
4684 }
4685
4686 /**
4687 * When an ident with name __FILE__, __DIR__, or __LINE__ is loaded, we'll try to look it up as any other
4688 * identifier. However, if it gets all the way up to the Global object, it will send back a special value that
4689 * represents a placeholder for these compile-time location properties. This method will generate code that loads
4690 * the value of the compile-time location property and then invokes a method in Global that will replace the
4691 * placeholder with the value. Effectively, if the symbol for these properties is defined anywhere in the lexical
4692 * scope, they take precedence, but if they aren't, then they resolve to the compile-time location property.
4693 * @param propertyValue the actual value of the property
4694 */
4695 private void replaceCompileTimeProperty(final Object propertyValue) {
4696 assert method.peekType().isObject();
4697 if(propertyValue instanceof String || propertyValue == null) {
4698 method.load((String)propertyValue);
4699 } else if(propertyValue instanceof Integer) {
4700 method.load(((Integer)propertyValue).intValue());
4701 method.convert(Type.OBJECT);
4702 } else {
4703 throw new AssertionError();
4704 }
4705 globalReplaceLocationPropertyPlaceholder();
4706 convertOptimisticReturnValue();
4707 }
4708
4709 /**
4710 * Returns the type that should be used as the return type of the dynamic invocation that is emitted as the code
4711 * for the current optimistic operation. If the type bounds is exact boolean or narrower than the expression's
4712 * optimistic type, then the optimistic type is returned, otherwise the coercing type. Effectively, this method
4713 * allows for moving the coercion into the optimistic type when it won't adversely affect the optimistic
4714 * evaluation semantics, and for preserving the optimistic type and doing a separate coercion when it would
4715 * affect it.
4716 * @return
4717 */
4718 private Type getOptimisticCoercedType() {
4719 final Type optimisticType = expression.getType();
4720 assert resultBounds.widest.widerThan(optimisticType);
4721 final Type narrowest = resultBounds.narrowest;
4722
4723 if(narrowest.isBoolean() || narrowest.narrowerThan(optimisticType)) {
4724 assert !optimisticType.isObject();
4725 return optimisticType;
4726 }
4727 assert !narrowest.isObject();
4728 return narrowest;
4729 }
4730 }
4731
4732 private static boolean isOptimistic(final Optimistic optimistic) {
4733 if(!optimistic.canBeOptimistic()) {
4734 return false;
4735 }
4736 final Expression expr = (Expression)optimistic;
4737 return expr.getType().narrowerThan(expr.getWidestOperationType());
4738 }
4739
4740 private static boolean everyLocalLoadIsValid(final int[] loads, final int localCount) {
4741 for (final int load : loads) {
4742 if(load < 0 || load >= localCount) {
4743 return false;
4744 }
4745 }
4746 return true;
4747 }
4748
4749 private static boolean everyStackValueIsLocalLoad(final int[] loads) {
4750 for (final int load : loads) {
4751 if(load == Label.Stack.NON_LOAD) {
4752 return false;
4753 }
4754 }
4755 return true;
4756 }
4757
4758 private String getLvarTypesDescriptor(final List<Type> localVarTypes) {
4759 final int count = localVarTypes.size();
4760 final StringBuilder desc = new StringBuilder(count);
4761 for(int i = 0; i < count;) {
4762 i += appendType(desc, localVarTypes.get(i));
4763 }
4764 return method.markSymbolBoundariesInLvarTypesDescriptor(desc.toString());
4765 }
4766
4767 private static int appendType(final StringBuilder b, final Type t) {
4768 b.append(t.getBytecodeStackType());
4769 return t.getSlots();
4770 }
4771
4772 private static int countSymbolsInLvarTypeDescriptor(final String lvarTypeDescriptor) {
4773 int count = 0;
4774 for(int i = 0; i < lvarTypeDescriptor.length(); ++i) {
4775 if(Character.isUpperCase(lvarTypeDescriptor.charAt(i))) {
4776 ++count;
4777 }
4778 }
4779 return count;
4780
4781 }
4782 /**
4783 * Generates all the required {@code UnwarrantedOptimismException} handlers for the current function. The employed
4784 * strategy strives to maximize code reuse. Every handler constructs an array to hold the local variables, then
4785 * fills in some trailing part of the local variables (those for which it has a unique suffix in the descriptor),
4786 * then jumps to a handler for a prefix that's shared with other handlers. A handler that fills up locals up to
4787 * position 0 will not jump to a prefix handler (as it has no prefix), but instead end with constructing and
4788 * throwing a {@code RewriteException}. Since we lexicographically sort the entries, we only need to check every
4789 * entry to its immediately preceding one for longest matching prefix.
4790 * @return true if there is at least one exception handler
4791 */
4792 private boolean generateUnwarrantedOptimismExceptionHandlers(final FunctionNode fn) {
4793 if(!useOptimisticTypes()) {
4794 return false;
4795 }
4796
4797 // Take the mapping of lvarSpecs -> labels, and turn them into a descending lexicographically sorted list of
4798 // handler specifications.
4799 final Map<String, Collection<Label>> unwarrantedOptimismHandlers = lc.popUnwarrantedOptimismHandlers();
4800 if(unwarrantedOptimismHandlers.isEmpty()) {
4801 return false;
4802 }
4803
4804 method.lineNumber(0);
4805
4806 final List<OptimismExceptionHandlerSpec> handlerSpecs = new ArrayList<>(unwarrantedOptimismHandlers.size() * 4/3);
4807 for(final String spec: unwarrantedOptimismHandlers.keySet()) {
4808 handlerSpecs.add(new OptimismExceptionHandlerSpec(spec, true));
4809 }
4810 Collections.sort(handlerSpecs, Collections.reverseOrder());
4811
4812 // Map of local variable specifications to labels for populating the array for that local variable spec.
4813 final Map<String, Label> delegationLabels = new HashMap<>();
4814
4815 // Do everything in a single pass over the handlerSpecs list. Note that the list can actually grow as we're
4816 // passing through it as we might add new prefix handlers into it, so can't hoist size() outside of the loop.
4817 for(int handlerIndex = 0; handlerIndex < handlerSpecs.size(); ++handlerIndex) {
4818 final OptimismExceptionHandlerSpec spec = handlerSpecs.get(handlerIndex);
4819 final String lvarSpec = spec.lvarSpec;
4820 if(spec.catchTarget) {
4821 assert !method.isReachable();
4822 // Start a catch block and assign the labels for this lvarSpec with it.
4823 method._catch(unwarrantedOptimismHandlers.get(lvarSpec));
4824 // This spec is a catch target, so emit array creation code. The length of the array is the number of
4825 // symbols - the number of uppercase characters.
4826 method.load(countSymbolsInLvarTypeDescriptor(lvarSpec));
4827 method.newarray(Type.OBJECT_ARRAY);
4828 }
4829 if(spec.delegationTarget) {
4830 // If another handler can delegate to this handler as its prefix, then put a jump target here for the
4831 // shared code (after the array creation code, which is never shared).
4832 method.label(delegationLabels.get(lvarSpec)); // label must exist
4833 }
4834
4835 final boolean lastHandler = handlerIndex == handlerSpecs.size() - 1;
4836
4837 int lvarIndex;
4838 final int firstArrayIndex;
4839 final int firstLvarIndex;
4840 Label delegationLabel;
4841 final String commonLvarSpec;
4842 if(lastHandler) {
4843 // Last handler block, doesn't delegate to anything.
4844 lvarIndex = 0;
4845 firstLvarIndex = 0;
4846 firstArrayIndex = 0;
4847 delegationLabel = null;
4848 commonLvarSpec = null;
4849 } else {
4850 // Not yet the last handler block, will definitely delegate to another handler; let's figure out which
4851 // one. It can be an already declared handler further down the list, or it might need to declare a new
4852 // prefix handler.
4853
4854 // Since we're lexicographically ordered, the common prefix handler is defined by the common prefix of
4855 // this handler and the next handler on the list.
4856 final int nextHandlerIndex = handlerIndex + 1;
4857 final String nextLvarSpec = handlerSpecs.get(nextHandlerIndex).lvarSpec;
4858 commonLvarSpec = commonPrefix(lvarSpec, nextLvarSpec);
4859 // We don't chop symbols in half
4860 assert Character.isUpperCase(commonLvarSpec.charAt(commonLvarSpec.length() - 1));
4861
4862 // Let's find if we already have a declaration for such handler, or we need to insert it.
4863 {
4864 boolean addNewHandler = true;
4865 int commonHandlerIndex = nextHandlerIndex;
4866 for(; commonHandlerIndex < handlerSpecs.size(); ++commonHandlerIndex) {
4867 final OptimismExceptionHandlerSpec forwardHandlerSpec = handlerSpecs.get(commonHandlerIndex);
4868 final String forwardLvarSpec = forwardHandlerSpec.lvarSpec;
4869 if(forwardLvarSpec.equals(commonLvarSpec)) {
4870 // We already have a handler for the common prefix.
4871 addNewHandler = false;
4872 // Make sure we mark it as a delegation target.
4873 forwardHandlerSpec.delegationTarget = true;
4874 break;
4875 } else if(!forwardLvarSpec.startsWith(commonLvarSpec)) {
4876 break;
4877 }
4878 }
4879 if(addNewHandler) {
4880 // We need to insert a common prefix handler. Note handlers created with catchTarget == false
4881 // will automatically have delegationTarget == true (because that's the only reason for their
4882 // existence).
4883 handlerSpecs.add(commonHandlerIndex, new OptimismExceptionHandlerSpec(commonLvarSpec, false));
4884 }
4885 }
4886
4887 firstArrayIndex = countSymbolsInLvarTypeDescriptor(commonLvarSpec);
4888 lvarIndex = 0;
4889 for(int j = 0; j < commonLvarSpec.length(); ++j) {
4890 lvarIndex += CodeGeneratorLexicalContext.getTypeForSlotDescriptor(commonLvarSpec.charAt(j)).getSlots();
4891 }
4892 firstLvarIndex = lvarIndex;
4893
4894 // Create a delegation label if not already present
4895 delegationLabel = delegationLabels.get(commonLvarSpec);
4896 if(delegationLabel == null) {
4897 // uo_pa == "unwarranted optimism, populate array"
4898 delegationLabel = new Label("uo_pa_" + commonLvarSpec);
4899 delegationLabels.put(commonLvarSpec, delegationLabel);
4900 }
4901 }
4902
4903 // Load local variables handled by this handler on stack
4904 int args = 0;
4905 boolean symbolHadValue = false;
4906 for(int typeIndex = commonLvarSpec == null ? 0 : commonLvarSpec.length(); typeIndex < lvarSpec.length(); ++typeIndex) {
4907 final char typeDesc = lvarSpec.charAt(typeIndex);
4908 final Type lvarType = CodeGeneratorLexicalContext.getTypeForSlotDescriptor(typeDesc);
4909 if (!lvarType.isUnknown()) {
4910 method.load(lvarType, lvarIndex);
4911 symbolHadValue = true;
4912 args++;
4913 } else if(typeDesc == 'U' && !symbolHadValue) {
4914 // Symbol boundary with undefined last value. Check if all previous values for this symbol were also
4915 // undefined; if so, emit one explicit Undefined. This serves to ensure that we're emiting exactly
4916 // one value for every symbol that uses local slots. While we could in theory ignore symbols that
4917 // are undefined (in other words, dead) at the point where this exception was thrown, unfortunately
4918 // we can't do it in practice. The reason for this is that currently our liveness analysis is
4919 // coarse (it can determine whether a symbol has not been read with a particular type anywhere in
4920 // the function being compiled, but that's it), and a symbol being promoted to Object due to a
4921 // deoptimization will suddenly show up as "live for Object type", and previously dead U->O
4922 // conversions on loop entries will suddenly become alive in the deoptimized method which will then
4923 // expect a value for that slot in its continuation handler. If we had precise liveness analysis, we
4924 // could go back to excluding known dead symbols from the payload of the RewriteException.
4925 if(method.peekType() == Type.UNDEFINED) {
4926 method.dup();
4927 } else {
4928 method.loadUndefined(Type.OBJECT);
4929 }
4930 args++;
4931 }
4932 if(Character.isUpperCase(typeDesc)) {
4933 // Reached symbol boundary; reset flag for the next symbol.
4934 symbolHadValue = false;
4935 }
4936 lvarIndex += lvarType.getSlots();
4937 }
4938 assert args > 0;
4939 // Delegate actual storing into array to an array populator utility method.
4940 //on the stack:
4941 // object array to be populated
4942 // start index
4943 // a lot of types
4944 method.dynamicArrayPopulatorCall(args + 1, firstArrayIndex);
4945 if(delegationLabel != null) {
4946 // We cascade to a prefix handler to fill out the rest of the local variables and throw the
4947 // RewriteException.
4948 assert !lastHandler;
4949 assert commonLvarSpec != null;
4950 // Must undefine the local variables that we have already processed for the sake of correct join on the
4951 // delegate label
4952 method.undefineLocalVariables(firstLvarIndex, true);
4953 final OptimismExceptionHandlerSpec nextSpec = handlerSpecs.get(handlerIndex + 1);
4954 // If the delegate immediately follows, and it's not a catch target (so it doesn't have array setup
4955 // code) don't bother emitting a jump, as we'd just jump to the next instruction.
4956 if(!nextSpec.lvarSpec.equals(commonLvarSpec) || nextSpec.catchTarget) {
4957 method._goto(delegationLabel);
4958 }
4959 } else {
4960 assert lastHandler;
4961 // Nothing to delegate to, so this handler must create and throw the RewriteException.
4962 // At this point we have the UnwarrantedOptimismException and the Object[] with local variables on
4963 // stack. We need to create a RewriteException, push two references to it below the constructor
4964 // arguments, invoke the constructor, and throw the exception.
4965 loadConstant(getByteCodeSymbolNames(fn));
4966 if (isRestOf()) {
4967 loadConstant(getContinuationEntryPoints());
4968 method.invoke(CREATE_REWRITE_EXCEPTION_REST_OF);
4969 } else {
4970 method.invoke(CREATE_REWRITE_EXCEPTION);
4971 }
4972 method.athrow();
4973 }
4974 }
4975 return true;
4976 }
4977
4978 private static String[] getByteCodeSymbolNames(final FunctionNode fn) {
4979 // Only names of local variables on the function level are captured. This information is used to reduce
4980 // deoptimizations, so as much as we can capture will help. We rely on the fact that function wide variables are
4981 // all live all the time, so the array passed to rewrite exception contains one element for every slotted symbol
4982 // here.
4983 final List<String> names = new ArrayList<>();
4984 for (final Symbol symbol: fn.getBody().getSymbols()) {
4985 if (symbol.hasSlot()) {
4986 if (symbol.isScope()) {
4987 // slot + scope can only be true for parameters
4988 assert symbol.isParam();
4989 names.add(null);
4990 } else {
4991 names.add(symbol.getName());
4992 }
4993 }
4994 }
4995 return names.toArray(new String[names.size()]);
4996 }
4997
4998 private static String commonPrefix(final String s1, final String s2) {
4999 final int l1 = s1.length();
5000 final int l = Math.min(l1, s2.length());
5001 int lms = -1; // last matching symbol
5002 for(int i = 0; i < l; ++i) {
5003 final char c1 = s1.charAt(i);
5004 if(c1 != s2.charAt(i)) {
5005 return s1.substring(0, lms + 1);
5006 } else if(Character.isUpperCase(c1)) {
5007 lms = i;
5008 }
5009 }
5010 return l == l1 ? s1 : s2;
5011 }
5012
5013 private static class OptimismExceptionHandlerSpec implements Comparable<OptimismExceptionHandlerSpec> {
5014 private final String lvarSpec;
5015 private final boolean catchTarget;
5016 private boolean delegationTarget;
5017
5018 OptimismExceptionHandlerSpec(final String lvarSpec, final boolean catchTarget) {
5019 this.lvarSpec = lvarSpec;
5020 this.catchTarget = catchTarget;
5021 if(!catchTarget) {
5022 delegationTarget = true;
5023 }
5024 }
5025
5026 @Override
5027 public int compareTo(final OptimismExceptionHandlerSpec o) {
5028 return lvarSpec.compareTo(o.lvarSpec);
5029 }
5030
5031 @Override
5032 public String toString() {
5033 final StringBuilder b = new StringBuilder(64).append("[HandlerSpec ").append(lvarSpec);
5034 if(catchTarget) {
5035 b.append(", catchTarget");
5036 }
5037 if(delegationTarget) {
5038 b.append(", delegationTarget");
5039 }
5040 return b.append("]").toString();
5041 }
5042 }
5043
5044 private static class ContinuationInfo {
5045 private final Label handlerLabel;
5046 private Label targetLabel; // Label for the target instruction.
5047 int lvarCount;
5048 // Indices of local variables that need to be loaded on the stack when this node completes
5049 private int[] stackStoreSpec;
5050 // Types of values loaded on the stack
5051 private Type[] stackTypes;
5052 // If non-null, this node should perform the requisite type conversion
5053 private Type returnValueType;
5054 // If we are in the middle of an object literal initialization, we need to update the map
5055 private PropertyMap objectLiteralMap;
5056 // Object literal stack depth for object literal - not necessarly top if property is a tree
5057 private int objectLiteralStackDepth = -1;
5058 // The line number at the continuation point
5059 private int lineNumber;
5060 // The active catch label, in case the continuation point is in a try/catch block
5061 private Label catchLabel;
5062 // The number of scopes that need to be popped before control is transferred to the catch label.
5063 private int exceptionScopePops;
5064
5065 ContinuationInfo() {
5066 this.handlerLabel = new Label("continuation_handler");
5067 }
5068
5069 Label getHandlerLabel() {
5070 return handlerLabel;
5071 }
5072
5073 boolean hasTargetLabel() {
5074 return targetLabel != null;
5075 }
5076
5077 Label getTargetLabel() {
5078 return targetLabel;
5079 }
5080
5081 void setTargetLabel(final Label targetLabel) {
5082 this.targetLabel = targetLabel;
5083 }
5084
5085 int[] getStackStoreSpec() {
5086 return stackStoreSpec.clone();
5087 }
5088
5089 void setStackStoreSpec(final int[] stackStoreSpec) {
5090 this.stackStoreSpec = stackStoreSpec;
5091 }
5092
5093 Type[] getStackTypes() {
5094 return stackTypes.clone();
5095 }
5096
5097 void setStackTypes(final Type[] stackTypes) {
5098 this.stackTypes = stackTypes;
5099 }
5100
5101 Type getReturnValueType() {
5102 return returnValueType;
5103 }
5104
5105 void setReturnValueType(final Type returnValueType) {
5106 this.returnValueType = returnValueType;
5107 }
5108
5109 int getObjectLiteralStackDepth() {
5110 return objectLiteralStackDepth;
5111 }
5112
5113 void setObjectLiteralStackDepth(final int objectLiteralStackDepth) {
5114 this.objectLiteralStackDepth = objectLiteralStackDepth;
5115 }
5116
5117 PropertyMap getObjectLiteralMap() {
5118 return objectLiteralMap;
5119 }
5120
5121 void setObjectLiteralMap(final PropertyMap objectLiteralMap) {
5122 this.objectLiteralMap = objectLiteralMap;
5123 }
5124
5125 @Override
5126 public String toString() {
5127 return "[localVariableTypes=" + targetLabel.getStack().getLocalVariableTypesCopy() + ", stackStoreSpec=" +
5128 Arrays.toString(stackStoreSpec) + ", returnValueType=" + returnValueType + "]";
5129 }
5130 }
5131
5132 private ContinuationInfo getContinuationInfo() {
5133 return fnIdToContinuationInfo.get(lc.getCurrentFunction().getId());
5134 }
5135
5136 private void generateContinuationHandler() {
5137 if (!isRestOf()) {
5138 return;
5139 }
5140
5141 final ContinuationInfo ci = getContinuationInfo();
5142 method.label(ci.getHandlerLabel());
5143
5144 // There should never be an exception thrown from the continuation handler, but in case there is (meaning,
5145 // Nashorn has a bug), then line number 0 will be an indication of where it came from (line numbers are Uint16).
5146 method.lineNumber(0);
5147
5148 final Label.Stack stack = ci.getTargetLabel().getStack();
5149 final List<Type> lvarTypes = stack.getLocalVariableTypesCopy();
5150 final BitSet symbolBoundary = stack.getSymbolBoundaryCopy();
5151 final int lvarCount = ci.lvarCount;
5152
5153 final Type rewriteExceptionType = Type.typeFor(RewriteException.class);
5154 // Store the RewriteException into an unused local variable slot.
5155 method.load(rewriteExceptionType, 0);
5156 method.storeTemp(rewriteExceptionType, lvarCount);
5157 // Get local variable array
5158 method.load(rewriteExceptionType, 0);
5159 method.invoke(RewriteException.GET_BYTECODE_SLOTS);
5160 // Store local variables. Note that deoptimization might introduce new value types for existing local variables,
5161 // so we must use both liveLocals and symbolBoundary, as in some cases (when the continuation is inside of a try
5162 // block) we need to store the incoming value into multiple slots. The optimism exception handlers will have
5163 // exactly one array element for every symbol that uses bytecode storage. If in the originating method the value
5164 // was undefined, there will be an explicit Undefined value in the array.
5165 int arrayIndex = 0;
5166 for(int lvarIndex = 0; lvarIndex < lvarCount;) {
5167 final Type lvarType = lvarTypes.get(lvarIndex);
5168 if(!lvarType.isUnknown()) {
5169 method.dup();
5170 method.load(arrayIndex).arrayload();
5171 final Class<?> typeClass = lvarType.getTypeClass();
5172 // Deoptimization in array initializers can cause arrays to undergo component type widening
5173 if(typeClass == long[].class) {
5174 method.load(rewriteExceptionType, lvarCount);
5175 method.invoke(RewriteException.TO_LONG_ARRAY);
5176 } else if(typeClass == double[].class) {
5177 method.load(rewriteExceptionType, lvarCount);
5178 method.invoke(RewriteException.TO_DOUBLE_ARRAY);
5179 } else if(typeClass == Object[].class) {
5180 method.load(rewriteExceptionType, lvarCount);
5181 method.invoke(RewriteException.TO_OBJECT_ARRAY);
5182 } else {
5183 if(!(typeClass.isPrimitive() || typeClass == Object.class)) {
5184 // NOTE: this can only happen with dead stores. E.g. for the program "1; []; f();" in which the
5185 // call to f() will deoptimize the call site, but it'll expect :return to have the type
5186 // NativeArray. However, in the more optimal version, :return's only live type is int, therefore
5187 // "{O}:return = []" is a dead store, and the variable will be sent into the continuation as
5188 // Undefined, however NativeArray can't hold Undefined instance.
5189 method.loadType(Type.getInternalName(typeClass));
5190 method.invoke(RewriteException.INSTANCE_OR_NULL);
5191 }
5192 method.convert(lvarType);
5193 }
5194 method.storeHidden(lvarType, lvarIndex, false);
5195 }
5196 final int nextLvarIndex = lvarIndex + lvarType.getSlots();
5197 if(symbolBoundary.get(nextLvarIndex - 1)) {
5198 ++arrayIndex;
5199 }
5200 lvarIndex = nextLvarIndex;
5201 }
5202 if (AssertsEnabled.assertsEnabled()) {
5203 method.load(arrayIndex);
5204 method.invoke(RewriteException.ASSERT_ARRAY_LENGTH);
5205 } else {
5206 method.pop();
5207 }
5208
5209 final int[] stackStoreSpec = ci.getStackStoreSpec();
5210 final Type[] stackTypes = ci.getStackTypes();
5211 final boolean isStackEmpty = stackStoreSpec.length == 0;
5212 boolean replacedObjectLiteralMap = false;
5213 if(!isStackEmpty) {
5214 // Load arguments on the stack
5215 final int objectLiteralStackDepth = ci.getObjectLiteralStackDepth();
5216 for(int i = 0; i < stackStoreSpec.length; ++i) {
5217 final int slot = stackStoreSpec[i];
5218 method.load(lvarTypes.get(slot), slot);
5219 method.convert(stackTypes[i]);
5220 // stack: s0=object literal being initialized
5221 // change map of s0 so that the property we are initilizing when we failed
5222 // is now ci.returnValueType
5223 if (i == objectLiteralStackDepth) {
5224 method.dup();
5225 assert ci.getObjectLiteralMap() != null;
5226 assert ScriptObject.class.isAssignableFrom(method.peekType().getTypeClass()) : method.peekType().getTypeClass() + " is not a script object";
5227 loadConstant(ci.getObjectLiteralMap());
5228 method.invoke(ScriptObject.SET_MAP);
5229 replacedObjectLiteralMap = true;
5230 }
5231 }
5232 }
5233 // Must have emitted the code for replacing the map of an object literal if we have a set object literal stack depth
5234 assert ci.getObjectLiteralStackDepth() == -1 || replacedObjectLiteralMap;
5235 // Load RewriteException back.
5236 method.load(rewriteExceptionType, lvarCount);
5237 // Get rid of the stored reference
5238 method.loadNull();
5239 method.storeHidden(Type.OBJECT, lvarCount);
5240 // Mark it dead
5241 method.markDeadSlots(lvarCount, Type.OBJECT.getSlots());
5242
5243 // Load return value on the stack
5244 method.invoke(RewriteException.GET_RETURN_VALUE);
5245
5246 final Type returnValueType = ci.getReturnValueType();
5247
5248 // Set up an exception handler for primitive type conversion of return value if needed
5249 boolean needsCatch = false;
5250 final Label targetCatchLabel = ci.catchLabel;
5251 Label _try = null;
5252 if(returnValueType.isPrimitive()) {
5253 // If the conversion throws an exception, we want to report the line number of the continuation point.
5254 method.lineNumber(ci.lineNumber);
5255
5256 if(targetCatchLabel != METHOD_BOUNDARY) {
5257 _try = new Label("");
5258 method.label(_try);
5259 needsCatch = true;
5260 }
5261 }
5262
5263 // Convert return value
5264 method.convert(returnValueType);
5265
5266 final int scopePopCount = needsCatch ? ci.exceptionScopePops : 0;
5267
5268 // Declare a try/catch for the conversion. If no scopes need to be popped until the target catch block, just
5269 // jump into it. Otherwise, we'll need to create a scope-popping catch block below.
5270 final Label catchLabel = scopePopCount > 0 ? new Label("") : targetCatchLabel;
5271 if(needsCatch) {
5272 final Label _end_try = new Label("");
5273 method.label(_end_try);
5274 method._try(_try, _end_try, catchLabel);
5275 }
5276
5277 // Jump to continuation point
5278 method._goto(ci.getTargetLabel());
5279
5280 // Make a scope-popping exception delegate if needed
5281 if(catchLabel != targetCatchLabel) {
5282 method.lineNumber(0);
5283 assert scopePopCount > 0;
5284 method._catch(catchLabel);
5285 popScopes(scopePopCount);
5286 method.uncheckedGoto(targetCatchLabel);
5287 }
5288 }
5289 }
--- EOF ---