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
48namespace 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
532