gecko-dev/js/js2/icodegenerator.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express oqr
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the JavaScript 2 Prototype.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation.  Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s): 
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU Public License (the "GPL"), in which case the
* provisions of the GPL are applicable instead of those above.
* If you wish to allow use of your version of this file only
* under the terms of the GPL and not to allow others to use your
* version of this file under the NPL, indicate your decision by
* deleting the provisions above and replace them with the notice
* and other provisions required by the GPL.  If you do not delete
* the provisions above, a recipient may use your version of this
* file under either the NPL or the GPL.
*/

#include "numerics.h"
#include "world.h"
#include "vmtypes.h"
#include "jstypes.h"
#include "icodegenerator.h"

#include <stdexcept>

namespace JavaScript {
namespace ICG {

using namespace VM;
using namespace JSTypes;

uint32 ICodeModule::sMaxID = 0;
    
Formatter& operator<<(Formatter &f, ICodeGenerator &i)
{
    return i.print(f);
}

Formatter& operator<<(Formatter &f, ICodeModule &i)
{
    return i.print(f);
}

//
// ICodeGenerator
//

ICodeGenerator::ICodeGenerator(World *world, bool hasTryStatement, uint32 switchStatementNesting)
    :   topRegister(0), 
        registerBase(0), 
        maxRegister(0), 
        parameterCount(0),
        exceptionRegister(NotARegister),
        switchRegister(NotARegister),
        variableList(new VariableList()),
        mWorld(world)
{ 
    iCode = new InstructionStream();
    iCodeOwner = true;
    if (hasTryStatement) 
        exceptionRegister = allocateVariable(world->identifiers[widenCString("__exceptionObject__")]);
    for (uint i = 0; i < switchStatementNesting; i++) {
        String s = widenCString("__switchControlVariable__");
        char num[8]; 
        sprintf(num, "%.2d", i);
        appendChars(s, num, strlen(num));
        if (switchRegister == NotARegister)
            switchRegister = allocateVariable(world->identifiers[s]);
        else
            allocateVariable(world->identifiers[s]);
    }
    labelSet = new StatementLabels();
}


ICodeModule *ICodeGenerator::complete()
{
    ASSERT(stitcher.empty());
    //ASSERT(labelSet == NULL);
#ifdef DEBUG
    for (LabelList::iterator i = labels.begin();
         i != labels.end(); i++) {
        ASSERT((*i)->mBase == iCode);
        ASSERT((*i)->mOffset <= iCode->size());
    }
#endif
    /*
    for (InstructionIterator ii = iCode->begin(); 
         ii != iCode->end(); ii++) {            
        if ((*ii)->op() == BRANCH) {
            Instruction *t = *ii;
            *ii = new ResolvedBranch(static_cast<Branch *>(*ii)->operand1->itsOffset);
            delete t;
        }
        else 
            if ((*ii)->itsOp >= BRANCH_LT && (*ii)->itsOp <= BRANCH_GT) {
                Instruction *t = *ii;
                *ii = new ResolvedBranchCond((*ii)->itsOp, 
                                             static_cast<BranchCond *>(*ii)->itsOperand1->itsOffset,
                                             static_cast<BranchCond *>(*ii)->itsOperand2);
                delete t;
            }
    }
    */
    markMaxRegister();
    ICodeModule* module = new ICodeModule(iCode, variableList, maxRegister, 0);
    iCodeOwner = false;   // give ownership to the module.
    return module;
}

TryCodeState::TryCodeState(Label *catchLabel, Label *finallyLabel, ICodeGenerator *icg) 
    : ICodeState(Try_state, icg), 
            catchHandler(catchLabel), 
            finallyHandler(finallyLabel),
            finallyInvoker(NULL),
            beyondCatch(NULL)
{ 
    if (catchHandler) {
        beyondCatch = icg->getLabel();
        if (finallyLabel)
            finallyInvoker = icg->getLabel();
    }
}


/********************************************************************/

Register ICodeGenerator::loadImmediate(double value)
{
    Register dest = getRegister();
    LoadImmediate *instr = new LoadImmediate(dest, value);
    iCode->push_back(instr);
    return dest;
}

Register ICodeGenerator::loadString(String &value)
{
    Register dest = getRegister();
    LoadString *instr = new LoadString(dest, new JSString(value));
    iCode->push_back(instr);
    return dest;
}

Register ICodeGenerator::loadValue(JSValue value)
{
    Register dest = getRegister();
    LoadValue *instr = new LoadValue(dest, value);
    iCode->push_back(instr);
    return dest;
}

Register ICodeGenerator::newObject()
{
    Register dest = getRegister();
    NewObject *instr = new NewObject(dest);
    iCode->push_back(instr);
    return dest;
}

Register ICodeGenerator::newArray()
{
    Register dest = getRegister();
    NewArray *instr = new NewArray(dest);
    iCode->push_back(instr);
    return dest;
}



Register ICodeGenerator::loadName(const StringAtom &name)
{
    Register dest = getRegister();
    LoadName *instr = new LoadName(dest, &name);
    iCode->push_back(instr);
    return dest;
}

void ICodeGenerator::saveName(const StringAtom &name, Register value)
{
    SaveName *instr = new SaveName(&name, value);
    iCode->push_back(instr);
}

Register ICodeGenerator::nameInc(const StringAtom &name)
{
    Register dest = getRegister();
    NameXcr *instr = new NameXcr(dest, &name, 1.0);
    iCode->push_back(instr);
    return dest;
}

Register ICodeGenerator::nameDec(const StringAtom &name)
{
    Register dest = getRegister();
    NameXcr *instr = new NameXcr(dest, &name, -1.0);
    iCode->push_back(instr);
    return dest;
}



Register ICodeGenerator::getProperty(Register base, const StringAtom &name)
{
    Register dest = getRegister();
    GetProp *instr = new GetProp(dest, base, &name);
    iCode->push_back(instr);
    return dest;
}

void ICodeGenerator::setProperty(Register base, const StringAtom &name,
                                 Register value)
{
    SetProp *instr = new SetProp(base, &name, value);
    iCode->push_back(instr);
}

Register ICodeGenerator::propertyInc(Register base, const StringAtom &name)
{
    Register dest = getRegister();
    PropXcr *instr = new PropXcr(dest, base, &name, 1.0);
    iCode->push_back(instr);
    return dest;
}

Register ICodeGenerator::propertyDec(Register base, const StringAtom &name)
{
    Register dest = getRegister();
    PropXcr *instr = new PropXcr(dest, base, &name, -1.0);
    iCode->push_back(instr);
    return dest;
}



Register ICodeGenerator::getElement(Register base, Register index)
{
    Register dest = getRegister();
    GetElement *instr = new GetElement(dest, base, index);
    iCode->push_back(instr);
    return dest;
}

void ICodeGenerator::setElement(Register base, Register index,
                                Register value)
{
    SetElement *instr = new SetElement(base, index, value);
    iCode->push_back(instr);
}

Register ICodeGenerator::elementInc(Register base, Register index)
{
    Register dest = getRegister();
    ElemXcr *instr = new ElemXcr(dest, base, index, 1.0);
    iCode->push_back(instr);
    return dest;
}

Register ICodeGenerator::elementDec(Register base, Register index)
{
    Register dest = getRegister();
    ElemXcr *instr = new ElemXcr(dest, base, index, -1.0);
    iCode->push_back(instr);
    return dest;
}


Register ICodeGenerator::op(ICodeOp op, Register source)
{
    Register dest = getRegister();
    ASSERT(source != NotARegister);    
    Compare *instr = new Compare (op, dest, source);
    iCode->push_back(instr);
    return dest;
}
    
void ICodeGenerator::move(Register destination, Register source)
{
    ASSERT(destination != NotARegister);    
    ASSERT(source != NotARegister);    
    Move *instr = new Move(destination, source);
    iCode->push_back(instr);
} 

void ICodeGenerator::complement(Register destination, Register source)
{
    Not *instr = new Not(destination, source);
    iCode->push_back(instr);
} 

Register ICodeGenerator::test(Register source)
{
    Register dest = getRegister();
    Test *instr = new Test(dest, source);
    iCode->push_back(instr);
    return dest;
}

Register ICodeGenerator::op(ICodeOp op, Register source1, 
                            Register source2)
{
    ASSERT(source1 != NotARegister);    
    ASSERT(source2 != NotARegister);    
    Register dest = getRegister();
    Arithmetic *instr = new Arithmetic(op, dest, source1, source2);
    iCode->push_back(instr);
    return dest;
} 
    
Register ICodeGenerator::call(Register target, RegisterList args)
{
    Register dest = getRegister();
    Call *instr = new Call(dest, target, args);
    iCode->push_back(instr);
    return dest;
}

void ICodeGenerator::callVoid(Register target, RegisterList args)
{
    Call *instr = new Call(NotARegister, target, args);
    iCode->push_back(instr);
}

void ICodeGenerator::branch(Label *label)
{
    Branch *instr = new Branch(label);
    iCode->push_back(instr);
}

void ICodeGenerator::branchConditional(Label *label, Register condition)
{
    ICodeOp branchOp = getBranchOp();
    ASSERT(branchOp != NOP);
    GenericBranch *instr = new GenericBranch(branchOp, label, condition);
    iCode->push_back(instr);
}

void ICodeGenerator::branchTrue(Label *label, Register condition)
{
    GenericBranch *instr = new GenericBranch(BRANCH_TRUE, label, condition);
    iCode->push_back(instr);
}

void ICodeGenerator::branchFalse(Label *label, Register condition)
{
    GenericBranch *instr = new GenericBranch(BRANCH_FALSE, label, condition);
    iCode->push_back(instr);
}

void ICodeGenerator::branchNotConditional(Label *label, Register condition)
{
    ICodeOp branchOp = getBranchOp();
    ASSERT(branchOp != NOP);
    switch (branchOp) {
        case BRANCH_FALSE   : branchOp = BRANCH_TRUE;   break;
        case BRANCH_TRUE    : branchOp = BRANCH_FALSE;  break;
        case BRANCH_EQ      : branchOp = BRANCH_NE;     break;
        case BRANCH_GE      : branchOp = BRANCH_LT;     break;
        case BRANCH_GT      : branchOp = BRANCH_LE;     break;
        case BRANCH_LE      : branchOp = BRANCH_GT;     break;
        case BRANCH_LT      : branchOp = BRANCH_GE;     break;
        case BRANCH_NE      : branchOp = BRANCH_EQ;     break;
        default : NOT_REACHED("Expected a branch op");  break;
    }
    GenericBranch *instr = new GenericBranch(branchOp, label, condition);
    iCode->push_back(instr);
}

/********************************************************************/

Label *ICodeGenerator::getLabel()
{
    labels.push_back(new Label(NULL));
    return labels.back();
}

void ICodeGenerator::setLabel(Label *l)
{
    l->mBase = iCode;
    l->mOffset = iCode->size();
}

void ICodeGenerator::setLabel(InstructionStream *stream, Label *l)
{
    l->mBase = stream;
    l->mOffset = stream->size();
}

/********************************************************************/

void ICodeGenerator::mergeStream(InstructionStream *sideStream)
{
    // change InstructionStream to be a class that also remembers
    // if it contains any labels (maybe even remembers the labels
    // themselves?) in order to avoid running this loop unnecessarily.
    for (LabelList::iterator i = labels.begin();
         i != labels.end(); i++) {
        if ((*i)->mBase == sideStream) {
            (*i)->mBase = iCode;
            (*i)->mOffset += iCode->size();
        }
    }

    for (InstructionIterator ii = sideStream->begin();
         ii != sideStream->end(); ii++) {
        iCode->push_back(*ii);
    }

}

/********************************************************************/

void ICodeGenerator::beginWhileStatement(uint32)
{
    WhileCodeState *ics = new WhileCodeState(this);
    addStitcher(ics);

    // insert a branch to the while condition, which we're 
    // moving to follow the while block
    branch(ics->whileCondition);

    iCode = new InstructionStream();
}

void ICodeGenerator::endWhileExpression(Register condition)
{
    WhileCodeState *ics = static_cast<WhileCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == While_state);

    branchConditional(ics->whileBody, condition);
    resetTopRegister();
    // stash away the condition expression and switch 
    // back to the main stream
    iCode = ics->swapStream(iCode);
    // mark the start of the while block
    setLabel(ics->whileBody);
}

void ICodeGenerator::endWhileStatement()
{
    // recover the while stream
    WhileCodeState *ics = static_cast<WhileCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == While_state);
    stitcher.pop_back();

        // mark the start of the condition code
        // which is where continues will target
    setLabel(ics->whileCondition);
    
    // and re-attach it to the main stream
    mergeStream(ics->whileExpressionStream);

    if (ics->breakLabel != NULL)
        setLabel(ics->breakLabel);

    delete ics;

    resetStatement();
}

/********************************************************************/

void ICodeGenerator::beginForStatement(uint32)
{
    ForCodeState *ics = new ForCodeState(this);
    addStitcher(ics);
    branch(ics->forCondition);

    // begin the stream for collecting the condition expression
    iCode = new InstructionStream();
    setLabel(ics->forCondition);

    resetTopRegister();
}

void ICodeGenerator::forCondition(Register condition)
{
    ForCodeState *ics = static_cast<ForCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == For_state);

    // finsh off the test expression by adding the branch to the body
    branchConditional(ics->forBody, condition);

    // switch back to main stream
    iCode = ics->swapStream(iCode);
    // begin the stream for collecting the increment expression
    iCode = new InstructionStream();

    ics->continueLabel = getLabel();
    // can't lazily insert this since we haven't seen the body yet
    // ??? could just remember the offset
    setLabel(ics->continueLabel);       

    resetTopRegister();
}

void ICodeGenerator::forIncrement()
{
    ForCodeState *ics = static_cast<ForCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == For_state);

    // now switch back to the main stream
    iCode = ics->swapStream2(iCode);
    setLabel(ics->forBody);

    resetTopRegister();
}

void ICodeGenerator::endForStatement()
{
    ForCodeState *ics = static_cast<ForCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == For_state);
    stitcher.pop_back();

    mergeStream(ics->forIncrementStream);
    mergeStream(ics->forConditionStream);

    if (ics->breakLabel != NULL)
        setLabel(ics->breakLabel);

    delete ics;
    resetStatement();
}

/********************************************************************/

void ICodeGenerator::beginDoStatement(uint32)
{
    DoCodeState *ics = new DoCodeState(this);
    addStitcher(ics);

    // mark the top of the loop body
    setLabel(ics->doBody);
}

void ICodeGenerator::endDoStatement()
{
    DoCodeState *ics = static_cast<DoCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Do_state);

    // mark the start of the do conditional
    setLabel(ics->doCondition);
    if (ics->continueLabel != NULL)
        setLabel(ics->continueLabel);

    resetTopRegister();
}

void ICodeGenerator::endDoExpression(Register condition)
{
    DoCodeState *ics = static_cast<DoCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Do_state);
    stitcher.pop_back();

    // add branch to top of do block
    branchConditional(ics->doBody, condition);
    if (ics->breakLabel != NULL)
        setLabel(ics->breakLabel);

    delete ics;

    resetStatement();
}

/********************************************************************/

void ICodeGenerator::beginSwitchStatement(uint32, Register expression)
{
    // stash the control expression value

    // hmmm, need to track depth of nesting here....
    move(switchRegister, expression);

    // build an instruction stream for the case statements, the case
    // expressions are generated into the main stream directly, the
    // case statements are then added back in afterwards.
    InstructionStream *x = new InstructionStream();
    SwitchCodeState *ics = new SwitchCodeState(switchRegister++, this);
    ics->swapStream(x);
    addStitcher(ics);
}

void ICodeGenerator::endCaseCondition(Register expression)
{
    SwitchCodeState *ics =
        static_cast<SwitchCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Switch_state);

    Label *caseLabel = getLabel();
    Register r = op(COMPARE_EQ, expression, ics->controlValue);
    branchConditional(caseLabel, r);

    // mark the case in the Case Statement stream 
    setLabel(ics->caseStatementsStream, caseLabel);
    resetTopRegister();
}

void ICodeGenerator::beginCaseStatement(uint32 /* pos */)
{
    SwitchCodeState *ics = 
        static_cast<SwitchCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Switch_state);
    // switch to Case Statement stream
    iCode = ics->swapStream(iCode);
}

void ICodeGenerator::endCaseStatement()
{
    SwitchCodeState *ics = 
        static_cast<SwitchCodeState *>(stitcher.back());
    // do more to guarantee correct blocking?
    ASSERT(ics->stateKind == Switch_state);
    // switch back to Case Conditional stream
    iCode = ics->swapStream(iCode);
    resetTopRegister();
}

void ICodeGenerator::beginDefaultStatement(uint32 /* pos */)
{
    SwitchCodeState *ics = 
        static_cast<SwitchCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Switch_state);
    ASSERT(ics->defaultLabel == NULL);
    ics->defaultLabel = getLabel();
    setLabel(ics->caseStatementsStream, ics->defaultLabel);
    // switch to Case Statement stream
    iCode = ics->swapStream(iCode);
}

void ICodeGenerator::endDefaultStatement()
{
    SwitchCodeState *ics = 
        static_cast<SwitchCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Switch_state);
    // do more to guarantee correct blocking?
    ASSERT(ics->defaultLabel != NULL);
    // switch to Case Statement stream
    iCode = ics->swapStream(iCode);
    resetTopRegister();
}

void ICodeGenerator::endSwitchStatement()
{
    SwitchCodeState *ics = 
        static_cast<SwitchCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Switch_state);
    stitcher.pop_back();

    // ground out the case chain at the default block or fall thru
    // to the break label
    if (ics->defaultLabel != NULL)       
        branch(ics->defaultLabel);
    else {
        if (ics->breakLabel == NULL)
            ics->breakLabel = getLabel();
        branch(ics->breakLabel);
    }

    // dump all the case statements into the main stream
    mergeStream(ics->caseStatementsStream);

    if (ics->breakLabel != NULL)
        setLabel(ics->breakLabel);

    delete ics;
    
    --switchRegister;

    resetStatement();
}


/********************************************************************/

void ICodeGenerator::beginIfStatement(uint32, Register condition)
{
    IfCodeState *ics = new IfCodeState(this);
    addStitcher(ics);

    branchNotConditional(ics->elseLabel, condition);

    resetTopRegister();
}

void ICodeGenerator::beginElseStatement(bool hasElse)
{
    IfCodeState *ics = static_cast<IfCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == If_state);

    if (hasElse) {
        Label *beyondElse = getLabel();
        ics->beyondElse = beyondElse;
        branch(beyondElse);
    }
    setLabel(ics->elseLabel);
    resetTopRegister();
}

void ICodeGenerator::endIfStatement()
{
    IfCodeState *ics = static_cast<IfCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == If_state);
    stitcher.pop_back();

    if (ics->beyondElse != NULL) {   // had an else
        setLabel(ics->beyondElse);   // the beyond else label
    }

    delete ics;
    resetStatement();
}

/************************************************************************/

void ICodeGenerator::breakStatement(uint32 /* pos */)
{
    for (std::vector<ICodeState *>::reverse_iterator p =
             stitcher.rbegin(); p != stitcher.rend(); p++) {
        if ((*p)->breakLabel != NULL) {
            branch((*p)->breakLabel);
            return;
        }
        if (((*p)->stateKind == While_state)
            || ((*p)->stateKind == Do_state)
            || ((*p)->stateKind == For_state)
            || ((*p)->stateKind == Switch_state)) {
            (*p)->breakLabel = getLabel();
            branch((*p)->breakLabel);
            return;
        }
    }
    NOT_REACHED("no break target available");
}

void ICodeGenerator::breakStatement(uint32 /* pos */,
                                    const StringAtom &label)
{
    for (std::vector<ICodeState *>::reverse_iterator p =
                stitcher.rbegin(); p != stitcher.rend(); p++) {
        if ((*p)->labelSet) {
            for (StatementLabels::iterator i = (*p)->labelSet->begin();
                        i != (*p)->labelSet->end(); i++) {
                if ((*i) == &label) {
		            if ((*p)->breakLabel == NULL)
			            (*p)->breakLabel = getLabel();
                    branch((*p)->breakLabel);
                    return;
                }
            }
        }
    }
    NOT_REACHED("no break target available");
}

void ICodeGenerator::continueStatement(uint32 /* pos */)
{
    for (std::vector<ICodeState *>::reverse_iterator p =
             stitcher.rbegin(); p != stitcher.rend(); p++) {
        if ((*p)->continueLabel != NULL) {
            branch((*p)->continueLabel);
            return;
        }
        if (((*p)->stateKind == While_state)
            || ((*p)->stateKind == Do_state)
            || ((*p)->stateKind == For_state)) {
            (*p)->continueLabel = getLabel();
            branch((*p)->continueLabel);
            return;
        }
    }
    NOT_REACHED("no continue target available");
}    

void ICodeGenerator::continueStatement(uint32 /* pos */,
                                       const StringAtom &label)
{
    for (std::vector<ICodeState *>::reverse_iterator p =
                stitcher.rbegin(); p != stitcher.rend(); p++) {
        if ((*p)->labelSet) {
            for (StatementLabels::iterator i = (*p)->labelSet->begin();
                        i != (*p)->labelSet->end(); i++) {
                if ((*i) == &label) {
        		    if ((*p)->continueLabel == NULL)
		            	(*p)->continueLabel = getLabel();
                    branch((*p)->continueLabel);
                    return;
                }
            }
        }
    }
    NOT_REACHED("no continue target available");
}
/********************************************************************/

void ICodeGenerator::beginTryStatement(uint32 /* pos */,
                                       bool hasCatch, bool hasFinally)
{
    ASSERT(exceptionRegister != NotARegister);
    TryCodeState *ics = new TryCodeState((hasCatch) ? getLabel() : NULL,
                                 (hasFinally) ? getLabel() : NULL, this);
    addStitcher(ics);
    beginTry(ics->catchHandler, ics->finallyInvoker);
}

void ICodeGenerator::endTryBlock()
{
    TryCodeState *ics = static_cast<TryCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Try_state);

    endTry();
    if (ics->finallyHandler)
        jsr(ics->finallyHandler);
    if (ics->beyondCatch)
        branch(ics->beyondCatch);
}

void ICodeGenerator::endTryStatement()
{
    TryCodeState *ics = static_cast<TryCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Try_state);
    stitcher.pop_back();
    if (ics->beyondCatch)
        setLabel(ics->beyondCatch);
    resetStatement();
}

void ICodeGenerator::beginCatchStatement(uint32 /* pos */)
{
    TryCodeState *ics = static_cast<TryCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Try_state);
    ASSERT(ics->catchHandler);
    setLabel(ics->catchHandler);
}

void ICodeGenerator::endCatchExpression(Register exceptionId)
{
    TryCodeState *ics = static_cast<TryCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Try_state);
    move(exceptionRegister, exceptionId);
}

void ICodeGenerator::endCatchStatement()
{
    TryCodeState *ics = static_cast<TryCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Try_state);
    if (ics->finallyHandler)
        jsr(ics->finallyHandler);
    throwStatement(0, exceptionRegister);
}

void ICodeGenerator::beginFinallyStatement(uint32 /* pos */)
{
    TryCodeState *ics = static_cast<TryCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Try_state);
    ASSERT(ics->finallyHandler);
    if (ics->finallyInvoker) {
        setLabel(ics->finallyInvoker);
        jsr(ics->finallyHandler);
        throwStatement(0, exceptionRegister);
    }
    setLabel(ics->finallyHandler);
}

void ICodeGenerator::endFinallyStatement()
{
    TryCodeState *ics = static_cast<TryCodeState *>(stitcher.back());
    ASSERT(ics->stateKind == Try_state);
    rts();
}

/************************************************************************/




ICodeOp ICodeGenerator::mapExprNodeToICodeOp(ExprNode::Kind kind)
{
    // can be an array later, when everything has settled down
    switch (kind) {
    // binary
    case ExprNode::add:
        return ADD;
    case ExprNode::subtract:
        return SUBTRACT;
    case ExprNode::multiply:
        return MULTIPLY;
    case ExprNode::divide:
        return DIVIDE;
    case ExprNode::modulo:
        return REMAINDER;
    case ExprNode::leftShift:
        return SHIFTLEFT;
    case ExprNode::rightShift:
        return SHIFTRIGHT;
    case ExprNode::logicalRightShift:
        return USHIFTRIGHT;
    case ExprNode::bitwiseAnd:
        return AND;
    case ExprNode::bitwiseXor:
        return XOR;
    case ExprNode::bitwiseOr:
        return OR;
    // unary
    case ExprNode::plus:
        return POSATE;
    case ExprNode::minus:
        return NEGATE;
    case ExprNode::complement:
        return NOT;

   // relational
    case ExprNode::equal:
        return COMPARE_EQ;
    case ExprNode::notEqual:
        return COMPARE_NE;
    case ExprNode::lessThan:
        return COMPARE_LT;
    case ExprNode::lessThanOrEqual:
        return COMPARE_LE;
    case ExprNode::greaterThan:
        return COMPARE_GT;
    case ExprNode::greaterThanOrEqual:
        return COMPARE_GE;
    case ExprNode::identical:
        return STRICT_EQ;
    case ExprNode::notIdentical:
        return STRICT_NE;
    case ExprNode::In:
        return COMPARE_IN;
    case ExprNode::Instanceof:
        return INSTANCEOF;


    default:
        NOT_REACHED("Unimplemented kind");
        return NOP;
    }
}


static bool generatedBoolean(ExprNode *p)
{
    switch (p->getKind()) {
    case ExprNode::parentheses: 
        {
            UnaryExprNode *u = static_cast<UnaryExprNode *>(p);
            return generatedBoolean(u->op);
        }
    case ExprNode::True:
    case ExprNode::False:
    case ExprNode::equal:
    case ExprNode::notEqual:
    case ExprNode::lessThan:
    case ExprNode::lessThanOrEqual:
    case ExprNode::greaterThan:
    case ExprNode::greaterThanOrEqual:
    case ExprNode::identical:
    case ExprNode::notIdentical:
    case ExprNode::In:
    case ExprNode::Instanceof:
    case ExprNode::logicalAnd:
    case ExprNode::logicalXor:
    case ExprNode::logicalOr:
        return true;
    }
    return false;
}


/*
    if trueBranch OR falseBranch are not null, the sub-expression should generate
    a conditional branch do the appropriate target. If either branch is NULL, it
    indicates that the label is immediately forthcoming.
*/
Register ICodeGenerator::genExpr(ExprNode *p, bool needBoolValueInBranch, Label *trueBranch, Label *falseBranch)
{
    Register ret = NotARegister;
    switch (p->getKind()) {
    case ExprNode::True:
        if (trueBranch || falseBranch) {
            if (needBoolValueInBranch)
                ret = loadValue(kTrue);
            if (trueBranch)
                branch(trueBranch);
        }
        else
            ret = loadValue(kTrue);
        break;
    case ExprNode::False:
        if (trueBranch || falseBranch) {
            if (needBoolValueInBranch)
                ret = loadValue(kFalse);
            if (falseBranch)
                branch(falseBranch);
        }
        else
            ret = loadValue(kFalse);
        break;
    case ExprNode::parentheses:
        {
            UnaryExprNode *u = static_cast<UnaryExprNode *>(p);
            ret = genExpr(u->op, needBoolValueInBranch, trueBranch, falseBranch);
        }
        break;
    case ExprNode::call : 
        {
            InvokeExprNode *i = static_cast<InvokeExprNode *>(p);
            Register fn = genExpr(i->op);
            RegisterList args;
            ExprPairList *p = i->pairs;
            while (p) {
                args.push_back(genExpr(p->value));
                p = p->next;
            }
            ret = call(fn, args);
        }
        break;
    case ExprNode::index :
        {
            BinaryExprNode *b = static_cast<BinaryExprNode *>(p);
            Register base = genExpr(b->op1);       
            Register index = genExpr(b->op2);
            ret = getElement(base, index);
        }
        break;
    case ExprNode::dot :
        {
            BinaryExprNode *b = static_cast<BinaryExprNode *>(p);
            Register base = genExpr(b->op1);            
            ret = getProperty(base, static_cast<IdentifierExprNode *>(b->op2)->name);
        }
        break;
    case ExprNode::identifier :
        {
            /*
                variable or name? If there's a 'with' in this scope, then it's
                a name, otherwise look it up in the function variable map.
            */

            ret = loadName((static_cast<IdentifierExprNode *>(p))->name);
        }
        break;
    case ExprNode::number :
        ret = loadImmediate((static_cast<NumberExprNode *>(p))->value);
        break;
    case ExprNode::string :
        ret = loadString(mWorld->identifiers[(static_cast<StringExprNode *>(p))->str]);
        break;
    case ExprNode::postIncrement: 
        {
            UnaryExprNode *u = static_cast<UnaryExprNode *>(p);
            if (u->op->getKind() == ExprNode::dot) {
                BinaryExprNode *b = static_cast<BinaryExprNode *>(u->op);
                Register base = genExpr(b->op1);
                ret = propertyInc(base, static_cast<IdentifierExprNode *>(b->op2)->name);
            }
            else
                if (u->op->getKind() == ExprNode::identifier) {
                    // variable or name? see above
                    ret = nameInc((static_cast<IdentifierExprNode *>(u->op))->name);
                }
                else
                    if (u->op->getKind() == ExprNode::index) {
                        BinaryExprNode *b = static_cast<BinaryExprNode *>(u->op);
                        Register base = genExpr(b->op1);
                        Register index = genExpr(b->op2);
                        ret = elementInc(base, index);
                    }
        }
        break;
    case ExprNode::postDecrement: 
        {
            UnaryExprNode *u = static_cast<UnaryExprNode *>(p);
            if (u->op->getKind() == ExprNode::dot) {
                BinaryExprNode *b = static_cast<BinaryExprNode *>(u->op);
                Register base = genExpr(b->op1);
                ret = propertyDec(base, static_cast<IdentifierExprNode *>(b->op2)->name);
            }
            else
                if (u->op->getKind() == ExprNode::identifier) {
                    // variable or name? see above
                    ret = nameDec((static_cast<IdentifierExprNode *>(u->op))->name);
                }
                else
                    if (u->op->getKind() == ExprNode::index) {
                        BinaryExprNode *b = static_cast<BinaryExprNode *>(u->op);
                        Register base = genExpr(b->op1);
                        Register index = genExpr(b->op2);
                        ret = elementInc(base, index);
                    }
        }
        break;
    case ExprNode::plus:
    case ExprNode::minus:
    case ExprNode::complement:
        {
            UnaryExprNode *u = static_cast<UnaryExprNode *>(p);
            Register r = genExpr(u->op);
            ret = op(mapExprNodeToICodeOp(p->getKind()), r);
        }
        break;
    case ExprNode::add:
    case ExprNode::subtract:
    case ExprNode::multiply:
    case ExprNode::divide:
    case ExprNode::modulo:
    case ExprNode::leftShift:
    case ExprNode::rightShift:
    case ExprNode::logicalRightShift:
    case ExprNode::bitwiseAnd:
    case ExprNode::bitwiseXor:
    case ExprNode::bitwiseOr:
        {
            BinaryExprNode *b = static_cast<BinaryExprNode *>(p);
            Register r1 = genExpr(b->op1);
            Register r2 = genExpr(b->op2);
            ret = op(mapExprNodeToICodeOp(p->getKind()), r1, r2);
        }
        break;
    case ExprNode::assignment:
        {
            BinaryExprNode *b = static_cast<BinaryExprNode *>(p);
            ret = genExpr(b->op2);
            if (b->op1->getKind() == ExprNode::identifier) {
                saveName((static_cast<IdentifierExprNode *>(b->op1))->name, ret);
            }
            else
                if (b->op1->getKind() == ExprNode::dot) {
                    BinaryExprNode *lb = static_cast<BinaryExprNode *>(b->op1);
                    Register base = genExpr(lb->op1);            
                    setProperty(base, static_cast<IdentifierExprNode *>(lb->op2)->name, ret);
                }
                else
                    if (b->op1->getKind() == ExprNode::index) {
                        BinaryExprNode *lb = static_cast<BinaryExprNode *>(b->op1);
                        Register base = genExpr(lb->op1);
                        Register index = genExpr(lb->op2);
                        setElement(base, index, ret);
                    }
        }
        break;
    case ExprNode::equal:
    case ExprNode::notEqual:
    case ExprNode::lessThan:
    case ExprNode::lessThanOrEqual:
    case ExprNode::greaterThan:
    case ExprNode::greaterThanOrEqual:
    case ExprNode::identical:
    case ExprNode::notIdentical:
    case ExprNode::In:
    case ExprNode::Instanceof:
        {
            BinaryExprNode *b = static_cast<BinaryExprNode *>(p);
            Register r1 = genExpr(b->op1);
            Register r2 = genExpr(b->op2);
            ret = op(mapExprNodeToICodeOp(p->getKind()), r1, r2);
            if (trueBranch || falseBranch) {
                if (trueBranch == NULL)
                    branchNotConditional(falseBranch, ret);
                else {
                    branchConditional(trueBranch, ret);
                    if (falseBranch)
                        branch(falseBranch);
                }
            }
        }
        break;
    case ExprNode::logicalAnd:
        {
            BinaryExprNode *b = static_cast<BinaryExprNode *>(p);
            if (trueBranch || falseBranch) {
                genExpr(b->op1, needBoolValueInBranch, NULL, falseBranch);
                genExpr(b->op2, needBoolValueInBranch, trueBranch, falseBranch);
            }
            else {
                Label *fBranch = getLabel();
                Register r1 = genExpr(b->op1, true, NULL, fBranch);
                if (!generatedBoolean(b->op1)) {
                    r1 = test(r1);
                    branchFalse(fBranch, r1);
                }
                Register r2 = genExpr(b->op2);
                if (!generatedBoolean(b->op2)) {
                    r2 = test(r2);
                }
                if (r1 != r2)       // FIXME, need a way to specify a dest???
                    move(r1, r2);
                setLabel(fBranch);
                ret = r1;
            }
        }
        break;
    case ExprNode::logicalOr:
        {
            BinaryExprNode *b = static_cast<BinaryExprNode *>(p);
            if (trueBranch || falseBranch) {
                genExpr(b->op1, needBoolValueInBranch, trueBranch, NULL);
                genExpr(b->op2, needBoolValueInBranch, trueBranch, falseBranch);
            }
            else {
                Label *tBranch = getLabel();
                Register r1 = genExpr(b->op1, true, tBranch, NULL);
                if (!generatedBoolean(b->op1)) {
                    r1 = test(r1);
                    branchTrue(tBranch, r1);
                }
                Register r2 = genExpr(b->op2);
                if (!generatedBoolean(b->op2)) {
                    r2 = test(r2);
                }
                if (r1 != r2)       // FIXME, need a way to specify a dest???
                    move(r1, r2);
                setLabel(tBranch);
                ret = r1;
            }
        }
        break;

    case ExprNode::conditional:
        {
            TernaryExprNode *t = static_cast<TernaryExprNode *>(p);
            Label *fBranch = getLabel();
            Label *beyondBranch = getLabel();
            Register c = genExpr(t->op1, false, NULL, fBranch);
            if (!generatedBoolean(t->op1)) {
                c = test(c);
                branchNotConditional(fBranch, c);
            }
            Register r1 = genExpr(t->op2);
            branch(beyondBranch);
            setLabel(fBranch);
            Register r2 = genExpr(t->op3);
            if (r1 != r2)       // FIXME, need a way to specify a dest???
                move(r1, r2);
            setLabel(beyondBranch);
            ret = r1;
        }
        break;
    }
    return ret;
}

/*
 pre-pass to find: 
    variable & function definitions,
    #nested switch statements
    contains 'with' or 'eval'
    contains 'try {} catch {} finally {}'
*/

/************************************************************************/


Formatter& ICodeGenerator::print(Formatter& f)
{
    f << "ICG! " << (uint32)iCode->size() << "\n"; // << *iCode;
    return VM::operator<<(f, *iCode);
}

Formatter& ICodeModule::print(Formatter& f)
{
    f << "ICM! " << (uint32)its_iCode->size() << "\n";
    return VM::operator<<(f, *its_iCode);
}

    
} // namespace ICG

} // namespace JavaScript