/*
 * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
 * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef CodeBlock_h
#define CodeBlock_h

#include "EvalCodeCache.h"
#include "Instruction.h"
#include "JSGlobalObject.h"
#include "JumpTable.h"
#include "Nodes.h"
#include "PtrAndFlags.h"
#include "RegExp.h"
#include "UString.h"
#include <wtf/FastAllocBase.h>
#include <wtf/RefPtr.h>
#include <wtf/Vector.h>

// Register numbers used in bytecode operations have different meaning accoring to their ranges:
//      0x80000000-0xFFFFFFFF  Negative indicies from the CallFrame pointer are entries in the call frame, see RegisterFile.h.
//      0x00000000-0x3FFFFFFF  Forwards indices from the CallFrame pointer are local vars and temporaries with the function's callframe.
//      0x40000000-0x7FFFFFFF  Positive indices from 0x40000000 specify entries in the constant pool on the CodeBlock.
static const int FirstConstantRegisterIndex = 0x40000000;

namespace JSC {

    enum HasSeenShouldRepatch {
        hasSeenShouldRepatch
    };

    class ExecState;

    enum CodeType { GlobalCode, EvalCode, FunctionCode };

    static ALWAYS_INLINE int missingThisObjectMarker() { return std::numeric_limits<int>::max(); }

    struct HandlerInfo {
        uint32_t start;
        uint32_t end;
        uint32_t target;
        uint32_t scopeDepth;
    };

    struct ExpressionRangeInfo {
        enum {
            MaxOffset = (1 << 7) - 1, 
            MaxDivot = (1 << 25) - 1
        };
        uint32_t instructionOffset : 25;
        uint32_t divotPoint : 25;
        uint32_t startOffset : 7;
        uint32_t endOffset : 7;
    };

    struct LineInfo {
        uint32_t instructionOffset;
        int32_t lineNumber;
    };

    // Both op_construct and op_instanceof require a use of op_get_by_id to get
    // the prototype property from an object. The exception messages for exceptions
    // thrown by these instances op_get_by_id need to reflect this.
    struct GetByIdExceptionInfo {
        unsigned bytecodeOffset : 31;
        bool isOpConstruct : 1;
    };

    struct ExceptionInfo : FastAllocBase {
        Vector<ExpressionRangeInfo> m_expressionInfo;
        Vector<LineInfo> m_lineInfo;
        Vector<GetByIdExceptionInfo> m_getByIdExceptionInfo;
    };

    class CodeBlock : public FastAllocBase {
    protected:
        CodeBlock(ScriptExecutable* ownerExecutable, CodeType, PassRefPtr<SourceProvider>, unsigned sourceOffset, SymbolTable* symbolTable);
    public:
        virtual ~CodeBlock();

        void markAggregate(MarkStack&);
        void refStructures(Instruction* vPC) const;
        void derefStructures(Instruction* vPC) const;

        static void dumpStatistics();

#if !defined(QT_NO_DEBUG) || ENABLE_OPCODE_SAMPLING
        void dump(ExecState*) const;
        void printStructures(const Instruction*) const;
        void printStructure(const char* name, const Instruction*, int operand) const;
#endif

        inline bool isKnownNotImmediate(int index)
        {
            if (index == m_thisRegister)
                return true;

            if (isConstantRegisterIndex(index))
                return getConstant(index).isCell();

            return false;
        }

        ALWAYS_INLINE bool isTemporaryRegisterIndex(int index)
        {
            return index >= m_numVars;
        }

        HandlerInfo* handlerForBytecodeOffset(unsigned bytecodeOffset);
        int lineNumberForBytecodeOffset(CallFrame*, unsigned bytecodeOffset);
        int expressionRangeForBytecodeOffset(CallFrame*, unsigned bytecodeOffset, int& divot, int& startOffset, int& endOffset);
        bool getByIdExceptionInfoForBytecodeOffset(CallFrame*, unsigned bytecodeOffset, OpcodeID&);

        void setIsNumericCompareFunction(bool isNumericCompareFunction) { m_isNumericCompareFunction = isNumericCompareFunction; }
        bool isNumericCompareFunction() { return m_isNumericCompareFunction; }

        Vector<Instruction>& instructions() { return m_instructions; }
        void discardBytecode() { m_instructions.clear(); }

#ifndef QT_NO_DEBUG
        unsigned instructionCount() { return m_instructionCount; }
        void setInstructionCount(unsigned instructionCount) { m_instructionCount = instructionCount; }
#endif

        ScriptExecutable* ownerExecutable() const { return m_ownerExecutable; }

        void setGlobalData(JSGlobalData* globalData) { m_globalData = globalData; }

        void setThisRegister(int thisRegister) { m_thisRegister = thisRegister; }
        int thisRegister() const { return m_thisRegister; }

        void setNeedsFullScopeChain(bool needsFullScopeChain) { m_needsFullScopeChain = needsFullScopeChain; }
        bool needsFullScopeChain() const { return m_needsFullScopeChain; }
        void setUsesEval(bool usesEval) { m_usesEval = usesEval; }
        bool usesEval() const { return m_usesEval; }
        void setUsesArguments(bool usesArguments) { m_usesArguments = usesArguments; }
        bool usesArguments() const { return m_usesArguments; }

        CodeType codeType() const { return m_codeType; }

        SourceProvider* source() const { return m_source.get(); }
        unsigned sourceOffset() const { return m_sourceOffset; }

        size_t numberOfJumpTargets() const { return m_jumpTargets.size(); }
        void addJumpTarget(unsigned jumpTarget) { m_jumpTargets.append(jumpTarget); }
        unsigned jumpTarget(int index) const { return m_jumpTargets[index]; }
        unsigned lastJumpTarget() const { return m_jumpTargets.last(); }

        void addPropertyAccessInstruction(unsigned propertyAccessInstruction) { m_propertyAccessInstructions.append(propertyAccessInstruction); }
        void addGlobalResolveInstruction(unsigned globalResolveInstruction) { m_globalResolveInstructions.append(globalResolveInstruction); }
        bool hasGlobalResolveInstructionAtBytecodeOffset(unsigned bytecodeOffset);

        // Exception handling support

        size_t numberOfExceptionHandlers() const { return m_rareData ? m_rareData->m_exceptionHandlers.size() : 0; }
        void addExceptionHandler(const HandlerInfo& hanler) { createRareDataIfNecessary(); return m_rareData->m_exceptionHandlers.append(hanler); }
        HandlerInfo& exceptionHandler(int index) { Q_ASSERT(m_rareData); return m_rareData->m_exceptionHandlers[index]; }

        bool hasExceptionInfo() const { return m_exceptionInfo; }
        void clearExceptionInfo() { m_exceptionInfo.clear(); }
        ExceptionInfo* extractExceptionInfo() { Q_ASSERT(m_exceptionInfo); return m_exceptionInfo.release(); }

        void addExpressionInfo(const ExpressionRangeInfo& expressionInfo) { Q_ASSERT(m_exceptionInfo); m_exceptionInfo->m_expressionInfo.append(expressionInfo); }
        void addGetByIdExceptionInfo(const GetByIdExceptionInfo& info) { Q_ASSERT(m_exceptionInfo); m_exceptionInfo->m_getByIdExceptionInfo.append(info); }

        size_t numberOfLineInfos() const { Q_ASSERT(m_exceptionInfo); return m_exceptionInfo->m_lineInfo.size(); }
        void addLineInfo(const LineInfo& lineInfo) { Q_ASSERT(m_exceptionInfo); m_exceptionInfo->m_lineInfo.append(lineInfo); }
        LineInfo& lastLineInfo() { Q_ASSERT(m_exceptionInfo); return m_exceptionInfo->m_lineInfo.last(); }

        // Constant Pool

        size_t numberOfIdentifiers() const { return m_identifiers.size(); }
        void addIdentifier(const Identifier& i) { return m_identifiers.append(i); }
        Identifier& identifier(int index) { return m_identifiers[index]; }

        size_t numberOfConstantRegisters() const { return m_constantRegisters.size(); }
        void addConstantRegister(const Register& r) { return m_constantRegisters.append(r); }
        Register& constantRegister(int index) { return m_constantRegisters[index - FirstConstantRegisterIndex]; }
        ALWAYS_INLINE bool isConstantRegisterIndex(int index) const { return index >= FirstConstantRegisterIndex; }
        ALWAYS_INLINE JSValue getConstant(int index) const { return m_constantRegisters[index - FirstConstantRegisterIndex].jsValue(); }

        unsigned addFunctionDecl(NonNullPassRefPtr<FunctionExecutable> n) { unsigned size = m_functionDecls.size(); m_functionDecls.append(n); return size; }
        FunctionExecutable* functionDecl(int index) { return m_functionDecls[index].get(); }
        int numberOfFunctionDecls() { return m_functionDecls.size(); }
        unsigned addFunctionExpr(NonNullPassRefPtr<FunctionExecutable> n) { unsigned size = m_functionExprs.size(); m_functionExprs.append(n); return size; }
        FunctionExecutable* functionExpr(int index) { return m_functionExprs[index].get(); }

        unsigned addRegExp(RegExp* r) { createRareDataIfNecessary(); unsigned size = m_rareData->m_regexps.size(); m_rareData->m_regexps.append(r); return size; }
        RegExp* regexp(int index) const { Q_ASSERT(m_rareData); return m_rareData->m_regexps[index].get(); }


        // Jump Tables

        size_t numberOfImmediateSwitchJumpTables() const { return m_rareData ? m_rareData->m_immediateSwitchJumpTables.size() : 0; }
        SimpleJumpTable& addImmediateSwitchJumpTable() { createRareDataIfNecessary(); m_rareData->m_immediateSwitchJumpTables.append(SimpleJumpTable()); return m_rareData->m_immediateSwitchJumpTables.last(); }
        SimpleJumpTable& immediateSwitchJumpTable(int tableIndex) { Q_ASSERT(m_rareData); return m_rareData->m_immediateSwitchJumpTables[tableIndex]; }

        size_t numberOfCharacterSwitchJumpTables() const { return m_rareData ? m_rareData->m_characterSwitchJumpTables.size() : 0; }
        SimpleJumpTable& addCharacterSwitchJumpTable() { createRareDataIfNecessary(); m_rareData->m_characterSwitchJumpTables.append(SimpleJumpTable()); return m_rareData->m_characterSwitchJumpTables.last(); }
        SimpleJumpTable& characterSwitchJumpTable(int tableIndex) { Q_ASSERT(m_rareData); return m_rareData->m_characterSwitchJumpTables[tableIndex]; }

        size_t numberOfStringSwitchJumpTables() const { return m_rareData ? m_rareData->m_stringSwitchJumpTables.size() : 0; }
        StringJumpTable& addStringSwitchJumpTable() { createRareDataIfNecessary(); m_rareData->m_stringSwitchJumpTables.append(StringJumpTable()); return m_rareData->m_stringSwitchJumpTables.last(); }
        StringJumpTable& stringSwitchJumpTable(int tableIndex) { Q_ASSERT(m_rareData); return m_rareData->m_stringSwitchJumpTables[tableIndex]; }


        SymbolTable* symbolTable() { return m_symbolTable; }
        SharedSymbolTable* sharedSymbolTable() { Q_ASSERT(m_codeType == FunctionCode); return static_cast<SharedSymbolTable*>(m_symbolTable); }

        EvalCodeCache& evalCodeCache() { createRareDataIfNecessary(); return m_rareData->m_evalCodeCache; }

        void shrinkToFit();

        // FIXME: Make these remaining members private.

        int m_numCalleeRegisters;
        int m_numVars;
        int m_numParameters;

    private:
#if !defined(QT_NO_DEBUG) || ENABLE(OPCODE_SAMPLING)
        void dump(ExecState*, const Vector<Instruction>::const_iterator& begin, Vector<Instruction>::const_iterator&) const;

        const char* registerName(ExecState*, int r) const;
        void printUnaryOp(ExecState*, int location, Vector<Instruction>::const_iterator&, const char* op) const;
        void printBinaryOp(ExecState*, int location, Vector<Instruction>::const_iterator&, const char* op) const;
        void printConditionalJump(ExecState*, const Vector<Instruction>::const_iterator&, Vector<Instruction>::const_iterator&, int location, const char* op) const;
        void printGetByIdOp(ExecState*, int location, Vector<Instruction>::const_iterator&, const char* op) const;
        void printPutByIdOp(ExecState*, int location, Vector<Instruction>::const_iterator&, const char* op) const;
#endif

        void reparseForExceptionInfoIfNecessary(CallFrame*);

        void createRareDataIfNecessary()
        {
            if (!m_rareData)
                m_rareData.set(new RareData);
        }

        ScriptExecutable* m_ownerExecutable;
        JSGlobalData* m_globalData;

        Vector<Instruction> m_instructions;
#ifndef QT_NO_DEBUG
        unsigned m_instructionCount;
#endif

        int m_thisRegister;

        bool m_needsFullScopeChain;
        bool m_usesEval;
        bool m_usesArguments;
        bool m_isNumericCompareFunction;

        CodeType m_codeType;

        RefPtr<SourceProvider> m_source;
        unsigned m_sourceOffset;

        Vector<unsigned> m_propertyAccessInstructions;
        Vector<unsigned> m_globalResolveInstructions;

        Vector<unsigned> m_jumpTargets;

        // Constant Pool
        Vector<Identifier> m_identifiers;
        Vector<Register> m_constantRegisters;
        Vector<RefPtr<FunctionExecutable> > m_functionDecls;
        Vector<RefPtr<FunctionExecutable> > m_functionExprs;

        SymbolTable* m_symbolTable;

        OwnPtr<ExceptionInfo> m_exceptionInfo;

        struct RareData : FastAllocBase {
            Vector<HandlerInfo> m_exceptionHandlers;

            // Rare Constants
            Vector<RefPtr<RegExp> > m_regexps;

            // Jump Tables
            Vector<SimpleJumpTable> m_immediateSwitchJumpTables;
            Vector<SimpleJumpTable> m_characterSwitchJumpTables;
            Vector<StringJumpTable> m_stringSwitchJumpTables;

            EvalCodeCache m_evalCodeCache;
        };
        OwnPtr<RareData> m_rareData;
    };

    // Program code is not marked by any function, so we make the global object
    // responsible for marking it.

    class GlobalCodeBlock : public CodeBlock {
    public:
        GlobalCodeBlock(ScriptExecutable* ownerExecutable, CodeType codeType, PassRefPtr<SourceProvider> sourceProvider, unsigned sourceOffset, JSGlobalObject* globalObject)
            : CodeBlock(ownerExecutable, codeType, sourceProvider, sourceOffset, &m_unsharedSymbolTable)
            , m_globalObject(globalObject)
        {
            m_globalObject->codeBlocks().add(this);
        }

        ~GlobalCodeBlock()
        {
            if (m_globalObject)
                m_globalObject->codeBlocks().remove(this);
        }

        void clearGlobalObject() { m_globalObject = 0; }

    private:
        JSGlobalObject* m_globalObject; // For program and eval nodes, the global object that marks the constant pool.
        SymbolTable m_unsharedSymbolTable;
    };

    class ProgramCodeBlock : public GlobalCodeBlock {
    public:
        ProgramCodeBlock(ProgramExecutable* ownerExecutable, CodeType codeType, JSGlobalObject* globalObject, PassRefPtr<SourceProvider> sourceProvider)
            : GlobalCodeBlock(ownerExecutable, codeType, sourceProvider, 0, globalObject)
        {
        }
    };

    class EvalCodeBlock : public GlobalCodeBlock {
    public:
        EvalCodeBlock(EvalExecutable* ownerExecutable, JSGlobalObject* globalObject, PassRefPtr<SourceProvider> sourceProvider, int baseScopeDepth)
            : GlobalCodeBlock(ownerExecutable, EvalCode, sourceProvider, 0, globalObject)
            , m_baseScopeDepth(baseScopeDepth)
        {
        }

        int baseScopeDepth() const { return m_baseScopeDepth; }

        const Identifier& variable(unsigned index) { return m_variables[index]; }
        unsigned numVariables() { return m_variables.size(); }
        void adoptVariables(Vector<Identifier>& variables)
        {
            Q_ASSERT(m_variables.isEmpty());
            m_variables.swap(variables);
        }

    private:
        int m_baseScopeDepth;
        Vector<Identifier> m_variables;
    };

    class FunctionCodeBlock : public CodeBlock {
    public:
        // Rather than using the usual RefCounted::create idiom for SharedSymbolTable we just use new
        // as we need to initialise the CodeBlock before we could initialise any RefPtr to hold the shared
        // symbol table, so we just pass as a raw pointer with a ref count of 1.  We then manually deref
        // in the destructor.
        FunctionCodeBlock(FunctionExecutable* ownerExecutable, CodeType codeType, PassRefPtr<SourceProvider> sourceProvider, unsigned sourceOffset)
            : CodeBlock(ownerExecutable, codeType, sourceProvider, sourceOffset, new SharedSymbolTable)
        {
        }
        ~FunctionCodeBlock()
        {
            sharedSymbolTable()->deref();
        }
    };

    inline Register& ExecState::r(int index)
    {
        CodeBlock* codeBlock = this->codeBlock();
        if (codeBlock->isConstantRegisterIndex(index))
            return codeBlock->constantRegister(index);
        return this[index];
    }

} // namespace JSC

#endif // CodeBlock_h
