bytecompiler/BytecodeGenerator.h

   1 /*
   2  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
   3  * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1.  Redistributions of source code must retain the above copyright
  10  *     notice, this list of conditions and the following disclaimer.
  11  * 2.  Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  15  *     its contributors may be used to endorse or promote products derived
  16  *     from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  22  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  24  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  25  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #ifndef BytecodeGenerator_h
  31 #define BytecodeGenerator_h
  32
  33 #include "CodeBlock.h"
  34 #include "HashTraits.h"
  35 #include "Instruction.h"
  36 #include "Label.h"
  37 #include "LabelScope.h"
  38 #include "Interpreter.h"
  39 #include "RegisterID.h"
  40 #include "SymbolTable.h"
  41 #include "Debugger.h"
  42 #include "Nodes.h"
  43 #include <wtf/FastAllocBase.h>
  44 #include <wtf/PassRefPtr.h>
  45 #include <wtf/SegmentedVector.h>
  46 #include <wtf/Vector.h>
  47
  48 namespace JSC {
  49
  50     class Identifier;
  51     class ScopeChain;
  52     class ScopeNode;
  53
  54     struct FinallyContext {
  55         Label* finallyAddr;
  56         RegisterID* retAddrDst;
  57     };
  58
  59     struct ControlFlowContext {
  60         bool isFinallyBlock;
  61         FinallyContext finallyContext;
  62     };
  63
  64     struct ForInContext {
  65         RefPtr<RegisterID> expectedSubscriptRegister;
  66         RefPtr<RegisterID> iterRegister;
  67         RefPtr<RegisterID> indexRegister;
  68         RefPtr<RegisterID> propertyRegister;
  69     };
  70
  71     class BytecodeGenerator : public FastAllocBase {
  72     public:
  73         typedef DeclarationStacks::VarStack VarStack;
  74         typedef DeclarationStacks::FunctionStack FunctionStack;
  75
  76         static void setDumpsGeneratedCode(bool dumpsGeneratedCode);
  77         static bool dumpsGeneratedCode();
  78
  79         BytecodeGenerator(ProgramNode*, const Debugger*, const ScopeChain&, SymbolTable*, ProgramCodeBlock*);
  80         BytecodeGenerator(FunctionBodyNode*, const Debugger*, const ScopeChain&, SymbolTable*, CodeBlock*);
  81         BytecodeGenerator(EvalNode*, const Debugger*, const ScopeChain&, SymbolTable*, EvalCodeBlock*);
  82
  83         JSGlobalData* globalData() const { return m_globalData; }
  84         const CommonIdentifiers& propertyNames() const { return *m_globalData->propertyNames; }
  85
  86         void generate();
  87
  88         // Returns the register corresponding to a local variable, or 0 if no
  89         // such register exists. Registers returned by registerFor do not
  90         // require explicit reference counting.
  91         RegisterID* registerFor(const Identifier&);
  92
  93         bool willResolveToArguments(const Identifier&);
  94         RegisterID* uncheckedRegisterForArguments();
  95
  96         // Behaves as registerFor does, but ignores dynamic scope as
  97         // dynamic scope should not interfere with const initialisation
  98         RegisterID* constRegisterFor(const Identifier&);
  99
 100         // Searches the scope chain in an attempt to  statically locate the requested
 101         // property.  Returns false if for any reason the property cannot be safely
 102         // optimised at all.  Otherwise it will return the index and depth of the
 103         // VariableObject that defines the property.  If the property cannot be found
 104         // statically, depth will contain the depth of the scope chain where dynamic
 105         // lookup must begin.
 106         //
 107         // NB: depth does _not_ include the local scope.  eg. a depth of 0 refers
 108         // to the scope containing this codeblock.
 109         bool findScopedProperty(const Identifier&, int& index, size_t& depth, bool forWriting, JSObject*& globalObject);
 110
 111         // Returns the register storing "this"
 112         RegisterID* thisRegister() { return &m_thisRegister; }
 113
 114         bool isLocal(const Identifier&);
 115         bool isLocalConstant(const Identifier&);
 116
 117         // Returns the next available temporary register. Registers returned by
 118         // newTemporary require a modified form of reference counting: any
 119         // register with a refcount of 0 is considered "available", meaning that
 120         // the next instruction may overwrite it.
 121         RegisterID* newTemporary();
 122
 123         RegisterID* highestUsedRegister();
 124
 125         // The same as newTemporary(), but this function returns "suggestion" if
 126         // "suggestion" is a temporary. This function is helpful in situations
 127         // where you've put "suggestion" in a RefPtr, but you'd like to allow
 128         // the next instruction to overwrite it anyway.
 129         RegisterID* newTemporaryOr(RegisterID* suggestion) { return suggestion->isTemporary() ? suggestion : newTemporary(); }
 130
 131         // Functions for handling of dst register
 132
 133         RegisterID* ignoredResult() { return &m_ignoredResultRegister; }
 134
 135         // Returns a place to write intermediate values of an operation
 136         // which reuses dst if it is safe to do so.
 137         RegisterID* tempDestination(RegisterID* dst)
 138         {
 139             return (dst && dst != ignoredResult() && dst->isTemporary()) ? dst : newTemporary();
 140         }
 141
 142         // Returns the place to write the final output of an operation.
 143         RegisterID* finalDestination(RegisterID* originalDst, RegisterID* tempDst = 0)
 144         {
 145             if (originalDst && originalDst != ignoredResult())
 146                 return originalDst;
 147             ASSERT(tempDst != ignoredResult());
 148             if (tempDst && tempDst->isTemporary())
 149                 return tempDst;
 150             return newTemporary();
 151         }
 152
 153         RegisterID* destinationForAssignResult(RegisterID* dst)
 154         {
 155             if (dst && dst != ignoredResult() && m_codeBlock->needsFullScopeChain())
 156                 return dst->isTemporary() ? dst : newTemporary();
 157             return 0;
 158         }
 159
 160         // Moves src to dst if dst is not null and is different from src, otherwise just returns src.
 161         RegisterID* moveToDestinationIfNeeded(RegisterID* dst, RegisterID* src)
 162         {
 163             return dst == ignoredResult() ? 0 : (dst && dst != src) ? emitMove(dst, src) : src;
 164         }
 165
 166         PassRefPtr<LabelScope> newLabelScope(LabelScope::Type, const Identifier* = 0);
 167         PassRefPtr<Label> newLabel();
 168
 169         // The emitNode functions are just syntactic sugar for calling
 170         // Node::emitCode. These functions accept a 0 for the register,
 171         // meaning that the node should allocate a register, or ignoredResult(),
 172         // meaning that the node need not put the result in a register.
 173         // Other emit functions do not accept 0 or ignoredResult().
 174         RegisterID* emitNode(RegisterID* dst, Node* n)
 175         {
 176             // Node::emitCode assumes that dst, if provided, is either a local or a referenced temporary.
 177             ASSERT(!dst || dst == ignoredResult() || !dst->isTemporary() || dst->refCount());
 178             if (!m_codeBlock->numberOfLineInfos() || m_codeBlock->lastLineInfo().lineNumber != n->lineNo()) {
 179                 LineInfo info = { instructions().size(), n->lineNo() };
 180                 m_codeBlock->addLineInfo(info);
 181             }
 182             if (m_emitNodeDepth >= s_maxEmitNodeDepth)
 183                 return emitThrowExpressionTooDeepException();
 184             ++m_emitNodeDepth;
 185             RegisterID* r = n->emitBytecode(*this, dst);
 186             --m_emitNodeDepth;
 187             return r;
 188         }
 189
 190         RegisterID* emitNode(Node* n)
 191         {
 192             return emitNode(0, n);
 193         }
 194
 195         void emitNodeInConditionContext(ExpressionNode* n, Label* trueTarget, Label* falseTarget, bool fallThroughMeansTrue)
 196         {
 197             if (!m_codeBlock->numberOfLineInfos() || m_codeBlock->lastLineInfo().lineNumber != n->lineNo()) {
 198                 LineInfo info = { instructions().size(), n->lineNo() };
 199                 m_codeBlock->addLineInfo(info);
 200             }
 201             if (m_emitNodeDepth >= s_maxEmitNodeDepth)
 202                 emitThrowExpressionTooDeepException();
 203             ++m_emitNodeDepth;
 204             n->emitBytecodeInConditionContext(*this, trueTarget, falseTarget, fallThroughMeansTrue);
 205             --m_emitNodeDepth;
 206         }
 207
 208         void emitExpressionInfo(unsigned divot, unsigned startOffset, unsigned endOffset)
 209         {
 210             divot -= m_codeBlock->sourceOffset();
 211             if (divot > ExpressionRangeInfo::MaxDivot) {
 212                 // Overflow has occurred, we can only give line number info for errors for this region
 213                 divot = 0;
 214                 startOffset = 0;
 215                 endOffset = 0;
 216             } else if (startOffset > ExpressionRangeInfo::MaxOffset) {
 217                 // If the start offset is out of bounds we clear both offsets
 218                 // so we only get the divot marker.  Error message will have to be reduced
 219                 // to line and column number.
 220                 startOffset = 0;
 221                 endOffset = 0;
 222             } else if (endOffset > ExpressionRangeInfo::MaxOffset) {
 223                 // The end offset is only used for additional context, and is much more likely
 224                 // to overflow (eg. function call arguments) so we are willing to drop it without
 225                 // dropping the rest of the range.
 226                 endOffset = 0;
 227             }
 228
 229             ExpressionRangeInfo info;
 230             info.instructionOffset = instructions().size();
 231             info.divotPoint = divot;
 232             info.startOffset = startOffset;
 233             info.endOffset = endOffset;
 234             m_codeBlock->addExpressionInfo(info);
 235         }
 236
 237         void emitGetByIdExceptionInfo(OpcodeID opcodeID)
 238         {
 239             // Only op_construct and op_instanceof need exception info for
 240             // a preceding op_get_by_id.
 241             ASSERT(opcodeID == op_construct || opcodeID == op_instanceof);
 242             GetByIdExceptionInfo info;
 243             info.bytecodeOffset = instructions().size();
 244             info.isOpConstruct = (opcodeID == op_construct);
 245             m_codeBlock->addGetByIdExceptionInfo(info);
 246         }
 247
 248         ALWAYS_INLINE bool leftHandSideNeedsCopy(bool rightHasAssignments, bool rightIsPure)
 249         {
 250             return (m_codeType != FunctionCode || m_codeBlock->needsFullScopeChain() || rightHasAssignments) && !rightIsPure;
 251         }
 252
 253         ALWAYS_INLINE PassRefPtr<RegisterID> emitNodeForLeftHandSide(ExpressionNode* n, bool rightHasAssignments, bool rightIsPure)
 254         {
 255             if (leftHandSideNeedsCopy(rightHasAssignments, rightIsPure)) {
 256                 PassRefPtr<RegisterID> dst = newTemporary();
 257                 emitNode(dst.get(), n);
 258                 return dst;
 259             }
 260
 261             return PassRefPtr<RegisterID>(emitNode(n));
 262         }
 263
 264         RegisterID* emitLoad(RegisterID* dst, bool);
 265         RegisterID* emitLoad(RegisterID* dst, double);
 266         RegisterID* emitLoad(RegisterID* dst, const Identifier&);
 267         RegisterID* emitLoad(RegisterID* dst, JSValue);
 268
 269         RegisterID* emitUnaryOp(OpcodeID, RegisterID* dst, RegisterID* src);
 270         RegisterID* emitBinaryOp(OpcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2, OperandTypes);
 271         RegisterID* emitEqualityOp(OpcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2);
 272         RegisterID* emitUnaryNoDstOp(OpcodeID, RegisterID* src);
 273
 274         RegisterID* emitNewObject(RegisterID* dst);
 275         RegisterID* emitNewArray(RegisterID* dst, ElementNode*); // stops at first elision
 276
 277         RegisterID* emitNewFunction(RegisterID* dst, FunctionBodyNode* body);
 278         RegisterID* emitNewFunctionExpression(RegisterID* dst, FuncExprNode* func);
 279         RegisterID* emitNewRegExp(RegisterID* dst, RegExp* regExp);
 280
 281         RegisterID* emitMove(RegisterID* dst, RegisterID* src);
 282
 283         RegisterID* emitToJSNumber(RegisterID* dst, RegisterID* src) { return emitUnaryOp(op_to_jsnumber, dst, src); }
 284         RegisterID* emitPreInc(RegisterID* srcDst);
 285         RegisterID* emitPreDec(RegisterID* srcDst);
 286         RegisterID* emitPostInc(RegisterID* dst, RegisterID* srcDst);
 287         RegisterID* emitPostDec(RegisterID* dst, RegisterID* srcDst);
 288
 289         RegisterID* emitInstanceOf(RegisterID* dst, RegisterID* value, RegisterID* base, RegisterID* basePrototype);
 290         RegisterID* emitTypeOf(RegisterID* dst, RegisterID* src) { return emitUnaryOp(op_typeof, dst, src); }
 291         RegisterID* emitIn(RegisterID* dst, RegisterID* property, RegisterID* base) { return emitBinaryOp(op_in, dst, property, base, OperandTypes()); }
 292
 293         RegisterID* emitResolve(RegisterID* dst, const Identifier& property);
 294         RegisterID* emitGetScopedVar(RegisterID* dst, size_t skip, int index, JSValue globalObject);
 295         RegisterID* emitPutScopedVar(size_t skip, int index, RegisterID* value, JSValue globalObject);
 296
 297         RegisterID* emitResolveBase(RegisterID* dst, const Identifier& property);
 298         RegisterID* emitResolveWithBase(RegisterID* baseDst, RegisterID* propDst, const Identifier& property);
 299
 300         void emitMethodCheck();
 301
 302         RegisterID* emitGetById(RegisterID* dst, RegisterID* base, const Identifier& property);
 303         RegisterID* emitPutById(RegisterID* base, const Identifier& property, RegisterID* value);
 304         RegisterID* emitDeleteById(RegisterID* dst, RegisterID* base, const Identifier&);
 305         RegisterID* emitGetByVal(RegisterID* dst, RegisterID* base, RegisterID* property);
 306         RegisterID* emitPutByVal(RegisterID* base, RegisterID* property, RegisterID* value);
 307         RegisterID* emitDeleteByVal(RegisterID* dst, RegisterID* base, RegisterID* property);
 308         RegisterID* emitPutByIndex(RegisterID* base, unsigned index, RegisterID* value);
 309         RegisterID* emitPutGetter(RegisterID* base, const Identifier& property, RegisterID* value);
 310         RegisterID* emitPutSetter(RegisterID* base, const Identifier& property, RegisterID* value);
 311
 312         RegisterID* emitCall(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, ArgumentsNode*, unsigned divot, unsigned startOffset, unsigned endOffset);
 313         RegisterID* emitCallEval(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, ArgumentsNode*, unsigned divot, unsigned startOffset, unsigned endOffset);
 314         RegisterID* emitCallVarargs(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, RegisterID* argCount, unsigned divot, unsigned startOffset, unsigned endOffset);
 315         RegisterID* emitLoadVarargs(RegisterID* argCountDst, RegisterID* args);
 316
 317         RegisterID* emitReturn(RegisterID* src);
 318         RegisterID* emitEnd(RegisterID* src) { return emitUnaryNoDstOp(op_end, src); }
 319
 320         RegisterID* emitConstruct(RegisterID* dst, RegisterID* func, ArgumentsNode*, unsigned divot, unsigned startOffset, unsigned endOffset);
 321         RegisterID* emitStrcat(RegisterID* dst, RegisterID* src, int count);
 322         void emitToPrimitive(RegisterID* dst, RegisterID* src);
 323
 324         PassRefPtr<Label> emitLabel(Label*);
 325         PassRefPtr<Label> emitJump(Label* target);
 326         PassRefPtr<Label> emitJumpIfTrue(RegisterID* cond, Label* target);
 327         PassRefPtr<Label> emitJumpIfFalse(RegisterID* cond, Label* target);
 328         PassRefPtr<Label> emitJumpIfNotFunctionCall(RegisterID* cond, Label* target);
 329         PassRefPtr<Label> emitJumpIfNotFunctionApply(RegisterID* cond, Label* target);
 330         PassRefPtr<Label> emitJumpScopes(Label* target, int targetScopeDepth);
 331
 332         PassRefPtr<Label> emitJumpSubroutine(RegisterID* retAddrDst, Label*);
 333         void emitSubroutineReturn(RegisterID* retAddrSrc);
 334
 335         RegisterID* emitGetPropertyNames(RegisterID* dst, RegisterID* base, RegisterID* i, RegisterID* size, Label* breakTarget);
 336         RegisterID* emitNextPropertyName(RegisterID* dst, RegisterID* base, RegisterID* i, RegisterID* size, RegisterID* iter, Label* target);
 337
 338         RegisterID* emitCatch(RegisterID*, Label* start, Label* end);
 339         void emitThrow(RegisterID* exc) { emitUnaryNoDstOp(op_throw, exc); }
 340         RegisterID* emitNewError(RegisterID* dst, ErrorType type, JSValue message);
 341         void emitPushNewScope(RegisterID* dst, const Identifier& property, RegisterID* value);
 342
 343         RegisterID* emitPushScope(RegisterID* scope);
 344         void emitPopScope();
 345
 346         void emitDebugHook(DebugHookID, int firstLine, int lastLine);
 347
 348         int scopeDepth() { return m_dynamicScopeDepth + m_finallyDepth; }
 349         bool hasFinaliser() { return m_finallyDepth != 0; }
 350
 351         void pushFinallyContext(Label* target, RegisterID* returnAddrDst);
 352         void popFinallyContext();
 353
 354         void pushOptimisedForIn(RegisterID* expectedBase, RegisterID* iter, RegisterID* index, RegisterID* propertyRegister)
 355         {
 356             ForInContext context = { expectedBase, iter, index, propertyRegister };
 357             m_forInContextStack.append(context);
 358         }
 359
 360         void popOptimisedForIn()
 361         {
 362             m_forInContextStack.removeLast();
 363         }
 364
 365         LabelScope* breakTarget(const Identifier&);
 366         LabelScope* continueTarget(const Identifier&);
 367
 368         void beginSwitch(RegisterID*, SwitchInfo::SwitchType);
 369         void endSwitch(uint32_t clauseCount, RefPtr<Label>*, ExpressionNode**, Label* defaultLabel, int32_t min, int32_t range);
 370
 371         CodeType codeType() const { return m_codeType; }
 372
 373         void setRegeneratingForExceptionInfo(CodeBlock* originalCodeBlock)
 374         {
 375             m_regeneratingForExceptionInfo = true;
 376             m_codeBlockBeingRegeneratedFrom = originalCodeBlock;
 377         }
 378
 379     private:
 380         void emitOpcode(OpcodeID);
 381         void retrieveLastBinaryOp(int& dstIndex, int& src1Index, int& src2Index);
 382         void retrieveLastUnaryOp(int& dstIndex, int& srcIndex);
 383         void rewindBinaryOp();
 384         void rewindUnaryOp();
 385
 386         PassRefPtr<Label> emitComplexJumpScopes(Label* target, ControlFlowContext* topScope, ControlFlowContext* bottomScope);
 387
 388         typedef HashMap<EncodedJSValue, unsigned, EncodedJSValueHash, EncodedJSValueHashTraits> JSValueMap;
 389
 390         struct IdentifierMapIndexHashTraits {
 391             typedef int TraitType;
 392             typedef IdentifierMapIndexHashTraits StorageTraits;
 393             static int emptyValue() { return std::numeric_limits<int>::max(); }
 394             static const bool emptyValueIsZero = false;
 395             static const bool needsDestruction = false;
 396             static const bool needsRef = false;
 397         };
 398
 399         typedef HashMap<RefPtr<UString::Rep>, int, IdentifierRepHash, HashTraits<RefPtr<UString::Rep> >, IdentifierMapIndexHashTraits> IdentifierMap;
 400         typedef HashMap<double, JSValue> NumberMap;
 401         typedef HashMap<UString::Rep*, JSString*, IdentifierRepHash> IdentifierStringMap;
 402
 403         RegisterID* emitCall(OpcodeID, RegisterID* dst, RegisterID* func, RegisterID* thisRegister, ArgumentsNode*, unsigned divot, unsigned startOffset, unsigned endOffset);
 404
 405         RegisterID* newRegister();
 406
 407         // Returns the RegisterID corresponding to ident.
 408         RegisterID* addVar(const Identifier& ident, bool isConstant)
 409         {
 410             RegisterID* local;
 411             addVar(ident, isConstant, local);
 412             return local;
 413         }
 414         // Returns true if a new RegisterID was added, false if a pre-existing RegisterID was re-used.
 415         bool addVar(const Identifier&, bool isConstant, RegisterID*&);
 416
 417         // Returns the RegisterID corresponding to ident.
 418         RegisterID* addGlobalVar(const Identifier& ident, bool isConstant)
 419         {
 420             RegisterID* local;
 421             addGlobalVar(ident, isConstant, local);
 422             return local;
 423         }
 424         // Returns true if a new RegisterID was added, false if a pre-existing RegisterID was re-used.
 425         bool addGlobalVar(const Identifier&, bool isConstant, RegisterID*&);
 426
 427         RegisterID* addParameter(const Identifier&);
 428
 429         void preserveLastVar();
 430
 431         RegisterID& registerFor(int index)
 432         {
 433             if (index >= 0)
 434                 return m_calleeRegisters[index];
 435
 436             if (index == RegisterFile::OptionalCalleeArguments)
 437                 return m_argumentsRegister;
 438
 439             if (m_parameters.size()) {
 440                 ASSERT(!m_globals.size());
 441                 return m_parameters[index + m_parameters.size() + RegisterFile::CallFrameHeaderSize];
 442             }
 443
 444             return m_globals[-index - 1];
 445         }
 446
 447         unsigned addConstant(const Identifier&);
 448         RegisterID* addConstantValue(JSValue);
 449         unsigned addRegExp(RegExp*);
 450
 451         PassRefPtr<FunctionExecutable> makeFunction(ExecState* exec, FunctionBodyNode* body)
 452         {
 453             return FunctionExecutable::create(exec, body->ident(), body->source(), body->usesArguments(), body->parameters(), body->lineNo(), body->lastLine());
 454         }
 455
 456         PassRefPtr<FunctionExecutable> makeFunction(JSGlobalData* globalData, FunctionBodyNode* body)
 457         {
 458             return FunctionExecutable::create(globalData, body->ident(), body->source(), body->usesArguments(), body->parameters(), body->lineNo(), body->lastLine());
 459         }
 460
 461         Vector<Instruction>& instructions() { return m_codeBlock->instructions(); }
 462         SymbolTable& symbolTable() { return *m_symbolTable; }
 463
 464         bool shouldOptimizeLocals() { return (m_codeType != EvalCode) && !m_dynamicScopeDepth; }
 465         bool canOptimizeNonLocals() { return (m_codeType == FunctionCode) && !m_dynamicScopeDepth && !m_codeBlock->usesEval(); }
 466
 467         RegisterID* emitThrowExpressionTooDeepException();
 468
 469         void createArgumentsIfNecessary();
 470
 471         bool m_shouldEmitDebugHooks;
 472         bool m_shouldEmitProfileHooks;
 473
 474         const ScopeChain* m_scopeChain;
 475         SymbolTable* m_symbolTable;
 476
 477         ScopeNode* m_scopeNode;
 478         CodeBlock* m_codeBlock;
 479
 480         // Some of these objects keep pointers to one another. They are arranged
 481         // to ensure a sane destruction order that avoids references to freed memory.
 482         HashSet<RefPtr<UString::Rep>, IdentifierRepHash> m_functions;
 483         RegisterID m_ignoredResultRegister;
 484         RegisterID m_thisRegister;
 485         RegisterID m_argumentsRegister;
 486         int m_activationRegisterIndex;
 487         SegmentedVector<RegisterID, 32> m_constantPoolRegisters;
 488         SegmentedVector<RegisterID, 32> m_calleeRegisters;
 489         SegmentedVector<RegisterID, 32> m_parameters;
 490         SegmentedVector<RegisterID, 32> m_globals;
 491         SegmentedVector<Label, 32> m_labels;
 492         SegmentedVector<LabelScope, 8> m_labelScopes;
 493         RefPtr<RegisterID> m_lastVar;
 494         int m_finallyDepth;
 495         int m_dynamicScopeDepth;
 496         int m_baseScopeDepth;
 497         CodeType m_codeType;
 498
 499         Vector<ControlFlowContext> m_scopeContextStack;
 500         Vector<SwitchInfo> m_switchContextStack;
 501         Vector<ForInContext> m_forInContextStack;
 502
 503         int m_nextGlobalIndex;
 504         int m_nextParameterIndex;
 505         int m_firstConstantIndex;
 506         int m_nextConstantOffset;
 507         unsigned m_globalConstantIndex;
 508
 509         int m_globalVarStorageOffset;
 510
 511         // Constant pool
 512         IdentifierMap m_identifierMap;
 513         JSValueMap m_jsValueMap;
 514         NumberMap m_numberMap;
 515         IdentifierStringMap m_stringMap;
 516
 517         JSGlobalData* m_globalData;
 518
 519         OpcodeID m_lastOpcodeID;
 520
 521         unsigned m_emitNodeDepth;
 522
 523         bool m_regeneratingForExceptionInfo;
 524         CodeBlock* m_codeBlockBeingRegeneratedFrom;
 525
 526         static const unsigned s_maxEmitNodeDepth = 5000;
 527     };
 528
 529 }
 530
 531 #endif // BytecodeGenerator_h