shared_source/c_tcl_base_7_5_w_mods/tclcompile.c

/* $Header$ */
/* 
 * tclCompile.c --
 *
 *      This file contains procedures that compile Tcl commands or parts
 *      of commands (like quoted strings or nested sub-commands) into a
 *      sequence of instructions ("bytecodes"). 
 *
 * Copyright (c) 1996-1998 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclcompile.c,v 1.1.1.1 2001/06/13 04:36:17 dtashley Exp $
 */

#include "tclInt.h"
#include "tclCompile.h"

/*
 * Table of all AuxData types.
 */
 
static Tcl_HashTable auxDataTypeTable;
static int auxDataTypeTableInitialized; /* 0 means not yet initialized. */

TCL_DECLARE_MUTEX(tableMutex)

/*
 * Variable that controls whether compilation tracing is enabled and, if so,
 * what level of tracing is desired:
 *    0: no compilation tracing
 *    1: summarize compilation of top level cmds and proc bodies
 *    2: display all instructions of each ByteCode compiled
 * This variable is linked to the Tcl variable "tcl_traceCompile".
 */

int tclTraceCompile = 0;
static int traceInitialized = 0;

/*
 * A table describing the Tcl bytecode instructions. Entries in this table
 * must correspond to the instruction opcode definitions in tclCompile.h.
 * The names "op1" and "op4" refer to an instruction's one or four byte
 * first operand. Similarly, "stktop" and "stknext" refer to the topmost
 * and next to topmost stack elements.
 *
 * Note that the load, store, and incr instructions do not distinguish local
 * from global variables; the bytecode interpreter at runtime uses the
 * existence of a procedure call frame to distinguish these.
 */

InstructionDesc instructionTable[] = {
   /* Name            Bytes #Opnds Operand types        Stack top, next   */
    {"done",              1,   0,   {OPERAND_NONE}},
        /* Finish ByteCode execution and return stktop (top stack item) */
    {"push1",             2,   1,   {OPERAND_UINT1}},
        /* Push object at ByteCode objArray[op1] */
    {"push4",             5,   1,   {OPERAND_UINT4}},
        /* Push object at ByteCode objArray[op4] */
    {"pop",               1,   0,   {OPERAND_NONE}},
        /* Pop the topmost stack object */
    {"dup",               1,   0,   {OPERAND_NONE}},
        /* Duplicate the topmost stack object and push the result */
    {"concat1",           2,   1,   {OPERAND_UINT1}},
        /* Concatenate the top op1 items and push result */
    {"invokeStk1",        2,   1,   {OPERAND_UINT1}},
        /* Invoke command named objv[0]; <objc,objv> = <op1,top op1> */
    {"invokeStk4",        5,   1,   {OPERAND_UINT4}},
        /* Invoke command named objv[0]; <objc,objv> = <op4,top op4> */
    {"evalStk",           1,   0,   {OPERAND_NONE}},
        /* Evaluate command in stktop using Tcl_EvalObj. */
    {"exprStk",           1,   0,   {OPERAND_NONE}},
        /* Execute expression in stktop using Tcl_ExprStringObj. */
    
    {"loadScalar1",       2,   1,   {OPERAND_UINT1}},
        /* Load scalar variable at index op1 <= 255 in call frame */
    {"loadScalar4",       5,   1,   {OPERAND_UINT4}},
        /* Load scalar variable at index op1 >= 256 in call frame */
    {"loadScalarStk",     1,   0,   {OPERAND_NONE}},
        /* Load scalar variable; scalar's name is stktop */
    {"loadArray1",        2,   1,   {OPERAND_UINT1}},
        /* Load array element; array at slot op1<=255, element is stktop */
    {"loadArray4",        5,   1,   {OPERAND_UINT4}},
        /* Load array element; array at slot op1 > 255, element is stktop */
    {"loadArrayStk",      1,   0,   {OPERAND_NONE}},
        /* Load array element; element is stktop, array name is stknext */
    {"loadStk",           1,   0,   {OPERAND_NONE}},
        /* Load general variable; unparsed variable name is stktop */
    {"storeScalar1",      2,   1,   {OPERAND_UINT1}},
        /* Store scalar variable at op1<=255 in frame; value is stktop */
    {"storeScalar4",      5,   1,   {OPERAND_UINT4}},
        /* Store scalar variable at op1 > 255 in frame; value is stktop */
    {"storeScalarStk",    1,   0,   {OPERAND_NONE}},
        /* Store scalar; value is stktop, scalar name is stknext */
    {"storeArray1",       2,   1,   {OPERAND_UINT1}},
        /* Store array element; array at op1<=255, value is top then elem */
    {"storeArray4",       5,   1,   {OPERAND_UINT4}},
        /* Store array element; array at op1>=256, value is top then elem */
    {"storeArrayStk",     1,   0,   {OPERAND_NONE}},
        /* Store array element; value is stktop, then elem, array names */
    {"storeStk",          1,   0,   {OPERAND_NONE}},
        /* Store general variable; value is stktop, then unparsed name */
    
    {"incrScalar1",       2,   1,   {OPERAND_UINT1}},
        /* Incr scalar at index op1<=255 in frame; incr amount is stktop */
    {"incrScalarStk",     1,   0,   {OPERAND_NONE}},
        /* Incr scalar; incr amount is stktop, scalar's name is stknext */
    {"incrArray1",        2,   1,   {OPERAND_UINT1}},
        /* Incr array elem; arr at slot op1<=255, amount is top then elem */
    {"incrArrayStk",      1,   0,   {OPERAND_NONE}},
        /* Incr array element; amount is top then elem then array names */
    {"incrStk",           1,   0,   {OPERAND_NONE}},
        /* Incr general variable; amount is stktop then unparsed var name */
    {"incrScalar1Imm",    3,   2,   {OPERAND_UINT1, OPERAND_INT1}},
        /* Incr scalar at slot op1 <= 255; amount is 2nd operand byte */
    {"incrScalarStkImm",  2,   1,   {OPERAND_INT1}},
        /* Incr scalar; scalar name is stktop; incr amount is op1 */
    {"incrArray1Imm",     3,   2,   {OPERAND_UINT1, OPERAND_INT1}},
        /* Incr array elem; array at slot op1 <= 255, elem is stktop,
         * amount is 2nd operand byte */
    {"incrArrayStkImm",   2,   1,   {OPERAND_INT1}},
        /* Incr array element; elem is top then array name, amount is op1 */
    {"incrStkImm",        2,   1,   {OPERAND_INT1}},
        /* Incr general variable; unparsed name is top, amount is op1 */
    
    {"jump1",             2,   1,   {OPERAND_INT1}},
        /* Jump relative to (pc + op1) */
    {"jump4",             5,   1,   {OPERAND_INT4}},
        /* Jump relative to (pc + op4) */
    {"jumpTrue1",         2,   1,   {OPERAND_INT1}},
        /* Jump relative to (pc + op1) if stktop expr object is true */
    {"jumpTrue4",         5,   1,   {OPERAND_INT4}},
        /* Jump relative to (pc + op4) if stktop expr object is true */
    {"jumpFalse1",        2,   1,   {OPERAND_INT1}},
        /* Jump relative to (pc + op1) if stktop expr object is false */
    {"jumpFalse4",        5,   1,   {OPERAND_INT4}},
        /* Jump relative to (pc + op4) if stktop expr object is false */

    {"lor",               1,   0,   {OPERAND_NONE}},
        /* Logical or:  push (stknext || stktop) */
    {"land",              1,   0,   {OPERAND_NONE}},
        /* Logical and: push (stknext && stktop) */
    {"bitor",             1,   0,   {OPERAND_NONE}},
        /* Bitwise or:  push (stknext | stktop) */
    {"bitxor",            1,   0,   {OPERAND_NONE}},
        /* Bitwise xor  push (stknext ^ stktop) */
    {"bitand",            1,   0,   {OPERAND_NONE}},
        /* Bitwise and: push (stknext & stktop) */
    {"eq",                1,   0,   {OPERAND_NONE}},
        /* Equal:       push (stknext == stktop) */
    {"neq",               1,   0,   {OPERAND_NONE}},
        /* Not equal:   push (stknext != stktop) */
    {"lt",                1,   0,   {OPERAND_NONE}},
        /* Less:        push (stknext < stktop) */
    {"gt",                1,   0,   {OPERAND_NONE}},
        /* Greater:     push (stknext || stktop) */
    {"le",                1,   0,   {OPERAND_NONE}},
        /* Logical or:  push (stknext || stktop) */
    {"ge",                1,   0,   {OPERAND_NONE}},
        /* Logical or:  push (stknext || stktop) */
    {"lshift",            1,   0,   {OPERAND_NONE}},
        /* Left shift:  push (stknext << stktop) */
    {"rshift",            1,   0,   {OPERAND_NONE}},
        /* Right shift: push (stknext >> stktop) */
    {"add",               1,   0,   {OPERAND_NONE}},
        /* Add:         push (stknext + stktop) */
    {"sub",               1,   0,   {OPERAND_NONE}},
        /* Sub:         push (stkext - stktop) */
    {"mult",              1,   0,   {OPERAND_NONE}},
        /* Multiply:    push (stknext * stktop) */
    {"div",               1,   0,   {OPERAND_NONE}},
        /* Divide:      push (stknext / stktop) */
    {"mod",               1,   0,   {OPERAND_NONE}},
        /* Mod:         push (stknext % stktop) */
    {"uplus",             1,   0,   {OPERAND_NONE}},
        /* Unary plus:  push +stktop */
    {"uminus",            1,   0,   {OPERAND_NONE}},
        /* Unary minus: push -stktop */
    {"bitnot",            1,   0,   {OPERAND_NONE}},
        /* Bitwise not: push ~stktop */
    {"not",               1,   0,   {OPERAND_NONE}},
        /* Logical not: push !stktop */
    {"callBuiltinFunc1",  2,   1,   {OPERAND_UINT1}},
        /* Call builtin math function with index op1; any args are on stk */
    {"callFunc1",         2,   1,   {OPERAND_UINT1}},
        /* Call non-builtin func objv[0]; <objc,objv>=<op1,top op1>  */
    {"tryCvtToNumeric",   1,   0,   {OPERAND_NONE}},
        /* Try converting stktop to first int then double if possible. */

    {"break",             1,   0,   {OPERAND_NONE}},
        /* Abort closest enclosing loop; if none, return TCL_BREAK code. */
    {"continue",          1,   0,   {OPERAND_NONE}},
        /* Skip to next iteration of closest enclosing loop; if none,
         * return TCL_CONTINUE code. */

    {"foreach_start4",    5,   1,   {OPERAND_UINT4}},
        /* Initialize execution of a foreach loop. Operand is aux data index
         * of the ForeachInfo structure for the foreach command. */
    {"foreach_step4",     5,   1,   {OPERAND_UINT4}},
        /* "Step" or begin next iteration of foreach loop. Push 0 if to
         *  terminate loop, else push 1. */

    {"beginCatch4",       5,   1,   {OPERAND_UINT4}},
        /* Record start of catch with the operand's exception index.
         * Push the current stack depth onto a special catch stack. */
    {"endCatch",          1,   0,   {OPERAND_NONE}},
        /* End of last catch. Pop the bytecode interpreter's catch stack. */
    {"pushResult",        1,   0,   {OPERAND_NONE}},
        /* Push the interpreter's object result onto the stack. */
    {"pushReturnCode",    1,   0,   {OPERAND_NONE}},
        /* Push interpreter's return code (e.g. TCL_OK or TCL_ERROR) as
         * a new object onto the stack. */
    {0}
};

/*
 * Prototypes for procedures defined later in this file:
 */

static void             DupByteCodeInternalRep _ANSI_ARGS_((Tcl_Obj *srcPtr,
                            Tcl_Obj *copyPtr));
static unsigned char *  EncodeCmdLocMap _ANSI_ARGS_((
                            CompileEnv *envPtr, ByteCode *codePtr,
                            unsigned char *startPtr));
static void             EnterCmdExtentData _ANSI_ARGS_((
                            CompileEnv *envPtr, int cmdNumber,
                            int numSrcBytes, int numCodeBytes));
static void             EnterCmdStartData _ANSI_ARGS_((
                            CompileEnv *envPtr, int cmdNumber,
                            int srcOffset, int codeOffset));
static void             FreeByteCodeInternalRep _ANSI_ARGS_((
                            Tcl_Obj *objPtr));
static int              GetCmdLocEncodingSize _ANSI_ARGS_((
                            CompileEnv *envPtr));
static void             LogCompilationInfo _ANSI_ARGS_((Tcl_Interp *interp,
                            char *script, char *command, int length));
#ifdef TCL_COMPILE_STATS
static void             RecordByteCodeStats _ANSI_ARGS_((
                            ByteCode *codePtr));
#endif /* TCL_COMPILE_STATS */
static int              SetByteCodeFromAny _ANSI_ARGS_((Tcl_Interp *interp,
                            Tcl_Obj *objPtr));

/*
 * The structure below defines the bytecode Tcl object type by
 * means of procedures that can be invoked by generic object code.
 */

Tcl_ObjType tclByteCodeType = {
    "bytecode",                         /* name */
    FreeByteCodeInternalRep,            /* freeIntRepProc */
    DupByteCodeInternalRep,             /* dupIntRepProc */
    (Tcl_UpdateStringProc *) NULL,      /* updateStringProc */
    SetByteCodeFromAny                  /* setFromAnyProc */
};

/*
 *----------------------------------------------------------------------
 *
 * TclSetByteCodeFromAny --
 *
 *      Part of the bytecode Tcl object type implementation. Attempts to
 *      generate an byte code internal form for the Tcl object "objPtr" by
 *      compiling its string representation.  This function also takes
 *      a hook procedure that will be invoked to perform any needed post
 *      processing on the compilation results before generating byte
 *      codes.
 *
 * Results:
 *      The return value is a standard Tcl object result. If an error occurs
 *      during compilation, an error message is left in the interpreter's
 *      result unless "interp" is NULL.
 *
 * Side effects:
 *      Frees the old internal representation. If no error occurs, then the
 *      compiled code is stored as "objPtr"s bytecode representation.
 *      Also, if debugging, initializes the "tcl_traceCompile" Tcl variable
 *      used to trace compilations.
 *
 *----------------------------------------------------------------------
 */

int
TclSetByteCodeFromAny(interp, objPtr, hookProc, clientData)
    Tcl_Interp *interp;         /* The interpreter for which the code is
                                 * being compiled.  Must not be NULL. */
    Tcl_Obj *objPtr;            /* The object to make a ByteCode object. */
    CompileHookProc *hookProc;  /* Procedure to invoke after compilation. */
    ClientData clientData;      /* Hook procedure private data. */
{
    Interp *iPtr = (Interp *) interp;
    CompileEnv compEnv;         /* Compilation environment structure
                                 * allocated in frame. */
    LiteralTable *localTablePtr = &(compEnv.localLitTable);
    register AuxData *auxDataPtr;
    LiteralEntry *entryPtr;
    register int i;
    int length, nested, result;
    char *string;

    if (!traceInitialized) {
        if (Tcl_LinkVar(interp, "tcl_traceCompile",
                    (char *) &tclTraceCompile,  TCL_LINK_INT) != TCL_OK) {
            panic("SetByteCodeFromAny: unable to create link for tcl_traceCompile variable");
        }
        traceInitialized = 1;
    }

    if (iPtr->evalFlags & TCL_BRACKET_TERM) {
        nested = 1;
    } else {
        nested = 0;
    }
    string = Tcl_GetStringFromObj(objPtr, &length);
    TclInitCompileEnv(interp, &compEnv, string, length);
    result = TclCompileScript(interp, string, length, nested, &compEnv);

    if (result == TCL_OK) {
        /*
         * Successful compilation. Add a "done" instruction at the end.
         */

        compEnv.numSrcBytes = iPtr->termOffset;
        TclEmitOpcode(INST_DONE, &compEnv);

        /*
         * Invoke the compilation hook procedure if one exists.
         */

        if (hookProc) {
            result = (*hookProc)(interp, &compEnv, clientData);
        }

        /*
         * Change the object into a ByteCode object. Ownership of the literal
         * objects and aux data items is given to the ByteCode object.
         */
    
#ifdef TCL_COMPILE_DEBUG
        TclVerifyLocalLiteralTable(&compEnv);
#endif /*TCL_COMPILE_DEBUG*/

        TclInitByteCodeObj(objPtr, &compEnv);
#ifdef TCL_COMPILE_DEBUG
        if (tclTraceCompile == 2) {
            TclPrintByteCodeObj(interp, objPtr);
        }
#endif /* TCL_COMPILE_DEBUG */
    }
        
    if (result != TCL_OK) {
        /*
         * Compilation errors. 
         */

        entryPtr = compEnv.literalArrayPtr;
        for (i = 0;  i < compEnv.literalArrayNext;  i++) {
            TclReleaseLiteral(interp, entryPtr->objPtr);
            entryPtr++;
        }
#ifdef TCL_COMPILE_DEBUG
        TclVerifyGlobalLiteralTable(iPtr);
#endif /*TCL_COMPILE_DEBUG*/

        auxDataPtr = compEnv.auxDataArrayPtr;
        for (i = 0;  i < compEnv.auxDataArrayNext;  i++) {
            if (auxDataPtr->type->freeProc != NULL) {
                auxDataPtr->type->freeProc(auxDataPtr->clientData);
            }
            auxDataPtr++;
        }
    }


    /*
     * Free storage allocated during compilation.
     */
    
    if (localTablePtr->buckets != localTablePtr->staticBuckets) {
        ckfree((char *) localTablePtr->buckets);
    }
    TclFreeCompileEnv(&compEnv);
    return result;
}

/*
 *-----------------------------------------------------------------------
 *
 * SetByteCodeFromAny --
 *
 *      Part of the bytecode Tcl object type implementation. Attempts to
 *      generate an byte code internal form for the Tcl object "objPtr" by
 *      compiling its string representation.
 *
 * Results:
 *      The return value is a standard Tcl object result. If an error occurs
 *      during compilation, an error message is left in the interpreter's
 *      result unless "interp" is NULL.
 *
 * Side effects:
 *      Frees the old internal representation. If no error occurs, then the
 *      compiled code is stored as "objPtr"s bytecode representation.
 *      Also, if debugging, initializes the "tcl_traceCompile" Tcl variable
 *      used to trace compilations.
 *
 *----------------------------------------------------------------------
 */

static int
SetByteCodeFromAny(interp, objPtr)
    Tcl_Interp *interp;         /* The interpreter for which the code is
                                 * being compiled.  Must not be NULL. */
    Tcl_Obj *objPtr;            /* The object to make a ByteCode object. */
{
    return TclSetByteCodeFromAny(interp, objPtr,
            (CompileHookProc *) NULL, (ClientData) NULL);
}

/*
 *----------------------------------------------------------------------
 *
 * DupByteCodeInternalRep --
 *
 *      Part of the bytecode Tcl object type implementation. However, it
 *      does not copy the internal representation of a bytecode Tcl_Obj, but
 *      instead leaves the new object untyped (with a NULL type pointer).
 *      Code will be compiled for the new object only if necessary.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

static void
DupByteCodeInternalRep(srcPtr, copyPtr)
    Tcl_Obj *srcPtr;            /* Object with internal rep to copy. */
    Tcl_Obj *copyPtr;           /* Object with internal rep to set. */
{
    return;
}

/*
 *----------------------------------------------------------------------
 *
 * FreeByteCodeInternalRep --
 *
 *      Part of the bytecode Tcl object type implementation. Frees the
 *      storage associated with a bytecode object's internal representation
 *      unless its code is actively being executed.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The bytecode object's internal rep is marked invalid and its
 *      code gets freed unless the code is actively being executed.
 *      In that case the cleanup is delayed until the last execution
 *      of the code completes.
 *
 *----------------------------------------------------------------------
 */

static void
FreeByteCodeInternalRep(objPtr)
    register Tcl_Obj *objPtr;   /* Object whose internal rep to free. */
{
    register ByteCode *codePtr =
            (ByteCode *) objPtr->internalRep.otherValuePtr;

    codePtr->refCount--;
    if (codePtr->refCount <= 0) {
        TclCleanupByteCode(codePtr);
    }
    objPtr->typePtr = NULL;
    objPtr->internalRep.otherValuePtr = NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCleanupByteCode --
 *
 *      This procedure does all the real work of freeing up a bytecode
 *      object's ByteCode structure. It's called only when the structure's
 *      reference count becomes zero.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Frees objPtr's bytecode internal representation and sets its type
 *      and objPtr->internalRep.otherValuePtr NULL. Also releases its
 *      literals and frees its auxiliary data items.
 *
 *----------------------------------------------------------------------
 */

void
TclCleanupByteCode(codePtr)
    register ByteCode *codePtr; /* Points to the ByteCode to free. */
{
    Tcl_Interp *interp = (Tcl_Interp *) *codePtr->interpHandle;
    int numLitObjects = codePtr->numLitObjects;
    int numAuxDataItems = codePtr->numAuxDataItems;
    register Tcl_Obj **objArrayPtr;
    register AuxData *auxDataPtr;
    int i;
#ifdef TCL_COMPILE_STATS

    if (interp != NULL) {
        ByteCodeStats *statsPtr;
        Tcl_Time destroyTime;
        int lifetimeSec, lifetimeMicroSec, log2;

        statsPtr = &((Interp *) interp)->stats;

        statsPtr->numByteCodesFreed++;
        statsPtr->currentSrcBytes -= (double) codePtr->numSrcBytes;
        statsPtr->currentByteCodeBytes -= (double) codePtr->structureSize;

        statsPtr->currentInstBytes   -= (double) codePtr->numCodeBytes;
        statsPtr->currentLitBytes    -=
                (double) (codePtr->numLitObjects * sizeof(Tcl_Obj *)); 
        statsPtr->currentExceptBytes -=
                (double) (codePtr->numExceptRanges * sizeof(ExceptionRange));
        statsPtr->currentAuxBytes    -=
                (double) (codePtr->numAuxDataItems * sizeof(AuxData));
        statsPtr->currentCmdMapBytes -= (double) codePtr->numCmdLocBytes;

        TclpGetTime(&destroyTime);
        lifetimeSec = destroyTime.sec - codePtr->createTime.sec;
        if (lifetimeSec > 2000) {       /* avoid overflow */
            lifetimeSec = 2000;
        }
        lifetimeMicroSec =
            1000000*lifetimeSec + (destroyTime.usec - codePtr->createTime.usec);
        
        log2 = TclLog2(lifetimeMicroSec);
        if (log2 > 31) {
            log2 = 31;
        }
        statsPtr->lifetimeCount[log2]++;
    }
#endif /* TCL_COMPILE_STATS */

    /*
     * A single heap object holds the ByteCode structure and its code,
     * object, command location, and auxiliary data arrays. This means we
     * only need to 1) decrement the ref counts of the LiteralEntry's in
     * its literal array, 2) call the free procs for the auxiliary data
     * items, and 3) free the ByteCode structure's heap object.
     *
     * The case for TCL_BYTECODE_PRECOMPILED (precompiled ByteCodes,
     * like those generated from tbcload) is special, as they doesn't
     * make use of the global literal table.  They instead maintain
     * private references to their literals which must be decremented.
     */

    if (codePtr->flags & TCL_BYTECODE_PRECOMPILED) {
        register Tcl_Obj *objPtr;
 
        objArrayPtr = codePtr->objArrayPtr;
        for (i = 0;  i < numLitObjects;  i++) {
            objPtr = *objArrayPtr;
            if (objPtr) {
                Tcl_DecrRefCount(objPtr);
            }
            objArrayPtr++;
        }
        codePtr->numLitObjects = 0;
    } else if (interp != NULL) {
        /*
         * If the interp has already been freed, then Tcl will have already 
         * forcefully released all the literals used by ByteCodes compiled
         * with respect to that interp.
         */
         
        objArrayPtr = codePtr->objArrayPtr;
        for (i = 0;  i < numLitObjects;  i++) {
            /*
             * TclReleaseLiteral sets a ByteCode's object array entry NULL to
             * indicate that it has already freed the literal.
             */
            
            if (*objArrayPtr != NULL) {
                TclReleaseLiteral(interp, *objArrayPtr);
            }
            objArrayPtr++;
        }
    }
    
    auxDataPtr = codePtr->auxDataArrayPtr;
    for (i = 0;  i < numAuxDataItems;  i++) {
        if (auxDataPtr->type->freeProc != NULL) {
            (*auxDataPtr->type->freeProc)(auxDataPtr->clientData);
        }
        auxDataPtr++;
    }

    TclHandleRelease(codePtr->interpHandle);
    ckfree((char *) codePtr);
}

/*
 *----------------------------------------------------------------------
 *
 * TclInitCompileEnv --
 *
 *      Initializes a CompileEnv compilation environment structure for the
 *      compilation of a string in an interpreter.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The CompileEnv structure is initialized.
 *
 *----------------------------------------------------------------------
 */

void
TclInitCompileEnv(interp, envPtr, string, numBytes)
    Tcl_Interp *interp;          /* The interpreter for which a CompileEnv
                                  * structure is initialized. */
    register CompileEnv *envPtr; /* Points to the CompileEnv structure to
                                  * initialize. */
    char *string;                /* The source string to be compiled. */
    int numBytes;                /* Number of bytes in source string. */
{
    Interp *iPtr = (Interp *) interp;
    
    envPtr->iPtr = iPtr;
    envPtr->source = string;
    envPtr->numSrcBytes = numBytes;
    envPtr->procPtr = iPtr->compiledProcPtr;
    envPtr->numCommands = 0;
    envPtr->exceptDepth = 0;
    envPtr->maxExceptDepth = 0;
    envPtr->maxStackDepth = 0;
    TclInitLiteralTable(&(envPtr->localLitTable));
    envPtr->exprIsJustVarRef = 0;
    envPtr->exprIsComparison = 0;

    envPtr->codeStart = envPtr->staticCodeSpace;
    envPtr->codeNext = envPtr->codeStart;
    envPtr->codeEnd = (envPtr->codeStart + COMPILEENV_INIT_CODE_BYTES);
    envPtr->mallocedCodeArray = 0;

    envPtr->literalArrayPtr = envPtr->staticLiteralSpace;
    envPtr->literalArrayNext = 0;
    envPtr->literalArrayEnd = COMPILEENV_INIT_NUM_OBJECTS;
    envPtr->mallocedLiteralArray = 0;
    
    envPtr->exceptArrayPtr = envPtr->staticExceptArraySpace;
    envPtr->exceptArrayNext = 0;
    envPtr->exceptArrayEnd = COMPILEENV_INIT_EXCEPT_RANGES;
    envPtr->mallocedExceptArray = 0;
    
    envPtr->cmdMapPtr = envPtr->staticCmdMapSpace;
    envPtr->cmdMapEnd = COMPILEENV_INIT_CMD_MAP_SIZE;
    envPtr->mallocedCmdMap = 0;
    
    envPtr->auxDataArrayPtr = envPtr->staticAuxDataArraySpace;
    envPtr->auxDataArrayNext = 0;
    envPtr->auxDataArrayEnd = COMPILEENV_INIT_AUX_DATA_SIZE;
    envPtr->mallocedAuxDataArray = 0;
}

/*
 *----------------------------------------------------------------------
 *
 * TclFreeCompileEnv --
 *
 *      Free the storage allocated in a CompileEnv compilation environment
 *      structure.
 *
 * Results:
 *      None.
 * 
 * Side effects:
 *      Allocated storage in the CompileEnv structure is freed. Note that
 *      its local literal table is not deleted and its literal objects are
 *      not released. In addition, storage referenced by its auxiliary data
 *      items is not freed. This is done so that, when compilation is
 *      successful, "ownership" of these objects and aux data items is
 *      handed over to the corresponding ByteCode structure.
 *
 *----------------------------------------------------------------------
 */

void
TclFreeCompileEnv(envPtr)
    register CompileEnv *envPtr; /* Points to the CompileEnv structure. */
{
    if (envPtr->mallocedCodeArray) {
        ckfree((char *) envPtr->codeStart);
    }
    if (envPtr->mallocedLiteralArray) {
        ckfree((char *) envPtr->literalArrayPtr);
    }
    if (envPtr->mallocedExceptArray) {
        ckfree((char *) envPtr->exceptArrayPtr);
    }
    if (envPtr->mallocedCmdMap) {
        ckfree((char *) envPtr->cmdMapPtr);
    }
    if (envPtr->mallocedAuxDataArray) {
        ckfree((char *) envPtr->auxDataArrayPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileScript --
 *
 *      Compile a Tcl script in a string.
 *
 * Results:
 *      The return value is TCL_OK on a successful compilation and TCL_ERROR
 *      on failure. If TCL_ERROR is returned, then the interpreter's result
 *      contains an error message.
 *
 *      interp->termOffset is set to the offset of the character in the
 *      script just after the last one successfully processed; this will be
 *      the offset of the ']' if (flags & TCL_BRACKET_TERM).
 *      envPtr->maxStackDepth is set to the maximum number of stack elements
 *      needed to execute the script's commands.
 *
 * Side effects:
 *      Adds instructions to envPtr to evaluate the script at runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileScript(interp, script, numBytes, nested, envPtr)
    Tcl_Interp *interp;         /* Used for error and status reporting. */
    char *script;               /* The source script to compile. */
    int numBytes;               /* Number of bytes in script. If < 0, the
                                 * script consists of all bytes up to the
                                 * first null character. */
    int nested;                 /* Non-zero means this is a nested command:
                                 * close bracket ']' should be considered a
                                 * command terminator. If zero, close
                                 * bracket has no special meaning. */
    CompileEnv *envPtr;         /* Holds resulting instructions. */
{
    Interp *iPtr = (Interp *) interp;
    Tcl_Parse parse;
    int maxDepth = 0;           /* Maximum number of stack elements needed
                                 * to execute all cmds. */
    int lastTopLevelCmdIndex = -1;
                                /* Index of most recent toplevel command in
                                 * the command location table. Initialized
                                 * to avoid compiler warning. */
    int startCodeOffset = -1;   /* Offset of first byte of current command's
                                 * code. Init. to avoid compiler warning. */
    unsigned char *entryCodeNext = envPtr->codeNext;
    char *p, *next;
    Namespace *cmdNsPtr;
    Command *cmdPtr;
    Tcl_Token *tokenPtr;
    int bytesLeft, isFirstCmd, gotParse, wordIdx, currCmdIndex;
    int commandLength, objIndex, code;
    char prev;
    Tcl_DString ds;

    Tcl_DStringInit(&ds);

    if (numBytes < 0) {
        numBytes = strlen(script);
    }
    Tcl_ResetResult(interp);
    isFirstCmd = 1;

    /*
     * Each iteration through the following loop compiles the next
     * command from the script.
     */

    p = script;
    bytesLeft = numBytes;
    gotParse = 0;
    while (bytesLeft > 0) {
        if (Tcl_ParseCommand(interp, p, bytesLeft, nested, &parse) != TCL_OK) {
            code = TCL_ERROR;
            goto error;
        }
        gotParse = 1;
        if (parse.numWords > 0) {
            /*
             * If not the first command, pop the previous command's result
             * and, if we're compiling a top level command, update the last
             * command's code size to account for the pop instruction.
             */

            if (!isFirstCmd) {
                TclEmitOpcode(INST_POP, envPtr);
                if (!nested) {
                    envPtr->cmdMapPtr[lastTopLevelCmdIndex].numCodeBytes =
                           (envPtr->codeNext - envPtr->codeStart)
                           - startCodeOffset;
                }
            }

            /*
             * Determine the actual length of the command.
             */

            commandLength = parse.commandSize;
            prev = '\0';
            if (commandLength > 0) {
                prev = parse.commandStart[commandLength-1];
            }
            if (((parse.commandStart+commandLength) != (script+numBytes))
                    || ((prev=='\n') || (nested && (prev==']')))) {
                /*
                 * The command didn't end at the end of the script (i.e.  it
                 * ended at a terminator character such as ";".  Reduce the
                 * length by one so that the trace message doesn't include
                 * the terminator character.
                 */
                
                commandLength -= 1;
            }

            /*
             * If tracing, print a line for each top level command compiled.
             */

            if ((tclTraceCompile >= 1)
                    && !nested && (envPtr->procPtr == NULL)) {
                fprintf(stdout, "  Compiling: ");
                TclPrintSource(stdout, parse.commandStart,
                        TclMin(commandLength, 55));
                fprintf(stdout, "\n");
            }

            /*
             * Each iteration of the following loop compiles one word
             * from the command.
             */
            
            envPtr->numCommands++;
            currCmdIndex = (envPtr->numCommands - 1);
            if (!nested) {
                lastTopLevelCmdIndex = currCmdIndex;
            }
            startCodeOffset = (envPtr->codeNext - envPtr->codeStart);
            EnterCmdStartData(envPtr, currCmdIndex,
                    (parse.commandStart - envPtr->source), startCodeOffset);
            
            for (wordIdx = 0, tokenPtr = parse.tokenPtr;
                    wordIdx < parse.numWords;
                    wordIdx++, tokenPtr += (tokenPtr->numComponents + 1)) {
                if (tokenPtr->type == TCL_TOKEN_SIMPLE_WORD) {
                    /*
                     * If this is the first word and the command has a
                     * compile procedure, let it compile the command.
                     */

                    if (wordIdx == 0) {
                        if (envPtr->procPtr != NULL) {
                            cmdNsPtr = envPtr->procPtr->cmdPtr->nsPtr;
                        } else {
                            cmdNsPtr = NULL; /* use current NS */
                        }

                        /*
                         * We copy the string before trying to find the command
                         * by name.  We used to modify the string in place, but
                         * this is not safe because the name resolution
                         * handlers could have side effects that rely on the
                         * unmodified string.
                         */

                        Tcl_DStringSetLength(&ds, 0);
                        Tcl_DStringAppend(&ds, tokenPtr[1].start,
                                tokenPtr[1].size);

                        cmdPtr = (Command *) Tcl_FindCommand(interp,
                                Tcl_DStringValue(&ds),
                                (Tcl_Namespace *) cmdNsPtr, /*flags*/ 0);

                        if ((cmdPtr != NULL)
                                && (cmdPtr->compileProc != NULL)
                                && !(iPtr->flags & DONT_COMPILE_CMDS_INLINE)) {
                            code = (*(cmdPtr->compileProc))(interp, &parse,
                                    envPtr);
                            if (code == TCL_OK) {
                                maxDepth = TclMax(envPtr->maxStackDepth,
                                        maxDepth);
                                goto finishCommand;
                            } else if (code == TCL_OUT_LINE_COMPILE) {
                                /* do nothing */
                            } else { /* an error */
                                /*
                                 * There was a compilation error, the last
                                 * command did not get compiled into (*envPtr).
                                 * Decrement the number of commands
                                 * claimed to be in (*envPtr).
                                 */
                                envPtr->numCommands--;
                                goto error;
                            }
                        }

                        /*
                         * No compile procedure so push the word. If the
                         * command was found, push a CmdName object to
                         * reduce runtime lookups.
                         */

                        objIndex = TclRegisterLiteral(envPtr,
                                tokenPtr[1].start, tokenPtr[1].size,
                                /*onHeap*/ 0);
                        if (cmdPtr != NULL) {
                            TclSetCmdNameObj(interp,
                                   envPtr->literalArrayPtr[objIndex].objPtr,
                                   cmdPtr);
                        }
                    } else {
                        objIndex = TclRegisterLiteral(envPtr,
                                tokenPtr[1].start, tokenPtr[1].size,
                                /*onHeap*/ 0);
                    }
                    TclEmitPush(objIndex, envPtr);
                    maxDepth = TclMax((wordIdx + 1), maxDepth);
                } else {
                    /*
                     * The word is not a simple string of characters.
                     */
                    
                    code = TclCompileTokens(interp, tokenPtr+1,
                            tokenPtr->numComponents, envPtr);
                    if (code != TCL_OK) {
                        goto error;
                    }
                    maxDepth = TclMax((wordIdx + envPtr->maxStackDepth),
                           maxDepth);
                }
            }

            /*
             * Emit an invoke instruction for the command. We skip this
             * if a compile procedure was found for the command.
             */
            
            if (wordIdx > 0) {
                if (wordIdx <= 255) {
                    TclEmitInstInt1(INST_INVOKE_STK1, wordIdx, envPtr);
                } else {
                    TclEmitInstInt4(INST_INVOKE_STK4, wordIdx, envPtr);
                }
            }

            /*
             * Update the compilation environment structure and record the
             * offsets of the source and code for the command.
             */

            finishCommand:
            EnterCmdExtentData(envPtr, currCmdIndex, commandLength,
                    (envPtr->codeNext-envPtr->codeStart) - startCodeOffset);
            isFirstCmd = 0;
        } /* end if parse.numWords > 0 */

        /*
         * Advance to the next command in the script.
         */
        
        next = parse.commandStart + parse.commandSize;
        bytesLeft -= (next - p);
        p = next;
        Tcl_FreeParse(&parse);
        gotParse = 0;
        if (nested && (p[-1] == ']')) {
            /*
             * We get here in the special case where TCL_BRACKET_TERM was
             * set in the interpreter and we reached a close bracket in the
             * script. Stop compilation.
             */
            
            break;
        }
    }

    /*
     * If the source script yielded no instructions (e.g., if it was empty),
     * push an empty string as the command's result.
     */
    
    if (envPtr->codeNext == entryCodeNext) {
        TclEmitPush(TclRegisterLiteral(envPtr, "", 0, /*onHeap*/ 0),
                envPtr);
        maxDepth = 1;
    }
    
    if ((nested != 0) && (p > script) && (p[-1] == ']')) {
        iPtr->termOffset = (p - 1) - script;
    } else {
        iPtr->termOffset = (p - script);
    }
    envPtr->maxStackDepth = maxDepth;
    Tcl_DStringFree(&ds);
    return TCL_OK;
        
    error:
    /*
     * Generate various pieces of error information, such as the line
     * number where the error occurred and information to add to the
     * errorInfo variable. Then free resources that had been allocated
     * to the command.
     */

    commandLength = parse.commandSize;
    prev = '\0';
    if (commandLength > 0) {
        prev = parse.commandStart[commandLength-1];
    }
    if (((parse.commandStart+commandLength) != (script+numBytes))
            || ((prev == '\n') || (nested && (prev == ']')))) {
        /*
         * The command where the error occurred didn't end at the end
         * of the script (i.e. it ended at a terminator character such
         * as ";".  Reduce the length by one so that the error message
         * doesn't include the terminator character.
         */

        commandLength -= 1;
    }
    LogCompilationInfo(interp, script, parse.commandStart, commandLength);
    if (gotParse) {
        Tcl_FreeParse(&parse);
    }
    iPtr->termOffset = (p - script);
    envPtr->maxStackDepth = maxDepth;
    Tcl_DStringFree(&ds);
    return code;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileTokens --
 *
 *      Given an array of tokens parsed from a Tcl command (e.g., the tokens
 *      that make up a word) this procedure emits instructions to evaluate
 *      the tokens and concatenate their values to form a single result
 *      value on the interpreter's runtime evaluation stack.
 *
 * Results:
 *      The return value is a standard Tcl result. If an error occurs, an
 *      error message is left in the interpreter's result.
 *      
 *      envPtr->maxStackDepth is updated with the maximum number of stack
 *      elements needed to evaluate the tokens.
 *
 * Side effects:
 *      Instructions are added to envPtr to push and evaluate the tokens
 *      at runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileTokens(interp, tokenPtr, count, envPtr)
    Tcl_Interp *interp;         /* Used for error and status reporting. */
    Tcl_Token *tokenPtr;        /* Pointer to first in an array of tokens
                                 * to compile. */
    int count;                  /* Number of tokens to consider at tokenPtr.
                                 * Must be at least 1. */
    CompileEnv *envPtr;         /* Holds the resulting instructions. */
{
    Tcl_DString textBuffer;     /* Holds concatenated chars from adjacent
                                 * TCL_TOKEN_TEXT, TCL_TOKEN_BS tokens. */
    char buffer[TCL_UTF_MAX];
    char *name, *p;
    int numObjsToConcat, nameBytes, hasNsQualifiers, localVar;
    int length, maxDepth, depthForVar, i, code;
    unsigned char *entryCodeNext = envPtr->codeNext;

    Tcl_DStringInit(&textBuffer);
    maxDepth = 0;
    numObjsToConcat = 0;
    for ( ;  count > 0;  count--, tokenPtr++) {
        switch (tokenPtr->type) {
            case TCL_TOKEN_TEXT:
                Tcl_DStringAppend(&textBuffer, tokenPtr->start,
                        tokenPtr->size);
                break;

            case TCL_TOKEN_BS:
                length = Tcl_UtfBackslash(tokenPtr->start, (int *) NULL,
                        buffer);
                Tcl_DStringAppend(&textBuffer, buffer, length);
                break;

            case TCL_TOKEN_COMMAND:
                /*
                 * Push any accumulated chars appearing before the command.
                 */
                
                if (Tcl_DStringLength(&textBuffer) > 0) {
                    int literal;
                    
                    literal = TclRegisterLiteral(envPtr,
                            Tcl_DStringValue(&textBuffer),
                            Tcl_DStringLength(&textBuffer), /*onHeap*/ 0);
                    TclEmitPush(literal, envPtr);
                    numObjsToConcat++;
                    maxDepth = TclMax(numObjsToConcat, maxDepth);
                    Tcl_DStringFree(&textBuffer);
                }
                
                code = TclCompileScript(interp, tokenPtr->start+1,
                        tokenPtr->size-2, /*nested*/ 1, envPtr);
                if (code != TCL_OK) {
                    goto error;
                }
                maxDepth = TclMax((numObjsToConcat + envPtr->maxStackDepth),
                        maxDepth);
                numObjsToConcat++;
                break;

            case TCL_TOKEN_VARIABLE:
                /*
                 * Push any accumulated chars appearing before the $<var>.
                 */
                
                if (Tcl_DStringLength(&textBuffer) > 0) {
                    int literal;
                    
                    literal = TclRegisterLiteral(envPtr,
                            Tcl_DStringValue(&textBuffer),
                            Tcl_DStringLength(&textBuffer), /*onHeap*/ 0);
                    TclEmitPush(literal, envPtr);
                    numObjsToConcat++;
                    maxDepth = TclMax(numObjsToConcat, maxDepth);
                    Tcl_DStringFree(&textBuffer);
                }
                
                /*
                 * Check if the name contains any namespace qualifiers.
                 */
                
                name = tokenPtr[1].start;
                nameBytes = tokenPtr[1].size;
                hasNsQualifiers = 0;
                for (i = 0, p = name;  i < nameBytes;  i++, p++) {
                    if ((*p == ':') && (i < (nameBytes-1))
                            && (*(p+1) == ':')) {
                        hasNsQualifiers = 1;
                        break;
                    }
                }

                /*
                 * Either push the variable's name, or find its index in
                 * the array of local variables in a procedure frame.
                 */

                depthForVar = 0;
                if ((envPtr->procPtr == NULL) || hasNsQualifiers) {
                    localVar = -1;
                    TclEmitPush(TclRegisterLiteral(envPtr, name, nameBytes,
                            /*onHeap*/ 0), envPtr);
                    depthForVar = 1;
                } else {
                    localVar = TclFindCompiledLocal(name, nameBytes, 
                            /*create*/ 0, /*flags*/ 0, envPtr->procPtr);
                    if (localVar < 0) {
                        TclEmitPush(TclRegisterLiteral(envPtr, name,
                                nameBytes, /*onHeap*/ 0), envPtr); 
                        depthForVar = 1;
                    }
                }

                /*
                 * Emit instructions to load the variable.
                 */
                
                if (tokenPtr->numComponents == 1) {
                    if (localVar < 0) {
                        TclEmitOpcode(INST_LOAD_SCALAR_STK, envPtr);
                    } else if (localVar <= 255) {
                        TclEmitInstInt1(INST_LOAD_SCALAR1, localVar,
                                envPtr);
                    } else {
                        TclEmitInstInt4(INST_LOAD_SCALAR4, localVar,
                                envPtr);
                    }
                } else {
                    code = TclCompileTokens(interp, tokenPtr+2,
                            tokenPtr->numComponents-1, envPtr);
                    if (code != TCL_OK) {
                        sprintf(buffer,
                                "\n    (parsing index for array \"%.*s\")",
                                ((nameBytes > 100)? 100 : nameBytes), name);
                        Tcl_AddObjErrorInfo(interp, buffer, -1);
                        goto error;
                    }
                    depthForVar += envPtr->maxStackDepth;
                    if (localVar < 0) {
                        TclEmitOpcode(INST_LOAD_ARRAY_STK, envPtr);
                    } else if (localVar <= 255) {
                        TclEmitInstInt1(INST_LOAD_ARRAY1, localVar,
                                envPtr);
                    } else {
                        TclEmitInstInt4(INST_LOAD_ARRAY4, localVar,
                                envPtr);
                    }
                }
                maxDepth = TclMax(numObjsToConcat + depthForVar, maxDepth);
                numObjsToConcat++;
                count -= tokenPtr->numComponents;
                tokenPtr += tokenPtr->numComponents;
                break;

            default:
                panic("Unexpected token type in TclCompileTokens");
        }
    }

    /*
     * Push any accumulated characters appearing at the end.
     */

    if (Tcl_DStringLength(&textBuffer) > 0) {
        int literal;

        literal = TclRegisterLiteral(envPtr, Tcl_DStringValue(&textBuffer),
                Tcl_DStringLength(&textBuffer), /*onHeap*/ 0);
        TclEmitPush(literal, envPtr);
        numObjsToConcat++;
        maxDepth = TclMax(numObjsToConcat, maxDepth);
    }

    /*
     * If necessary, concatenate the parts of the word.
     */

    while (numObjsToConcat > 255) {
        TclEmitInstInt1(INST_CONCAT1, 255, envPtr);
        numObjsToConcat -= 254; /* concat pushes 1 obj, the result */
    }
    if (numObjsToConcat > 1) {
        TclEmitInstInt1(INST_CONCAT1, numObjsToConcat, envPtr);
    }

    /*
     * If the tokens yielded no instructions, push an empty string.
     */
    
    if (envPtr->codeNext == entryCodeNext) {
        TclEmitPush(TclRegisterLiteral(envPtr, "", 0, /*onHeap*/ 0),
                envPtr);
        maxDepth = 1;
    }
    Tcl_DStringFree(&textBuffer);
    envPtr->maxStackDepth = maxDepth;
    return TCL_OK;

    error:
    Tcl_DStringFree(&textBuffer);
    envPtr->maxStackDepth = maxDepth;
    return code;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileCmdWord --
 *
 *      Given an array of parse tokens for a word containing one or more Tcl
 *      commands, emit inline instructions to execute them. This procedure
 *      differs from TclCompileTokens in that a simple word such as a loop
 *      body enclosed in braces is not just pushed as a string, but is
 *      itself parsed into tokens and compiled.
 *
 * Results:
 *      The return value is a standard Tcl result. If an error occurs, an
 *      error message is left in the interpreter's result.
 *      
 *      envPtr->maxStackDepth is updated with the maximum number of stack
 *      elements needed to execute the tokens.
 *
 * Side effects:
 *      Instructions are added to envPtr to execute the tokens at runtime.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileCmdWord(interp, tokenPtr, count, envPtr)
    Tcl_Interp *interp;         /* Used for error and status reporting. */
    Tcl_Token *tokenPtr;        /* Pointer to first in an array of tokens
                                 * for a command word to compile inline. */
    int count;                  /* Number of tokens to consider at tokenPtr.
                                 * Must be at least 1. */
    CompileEnv *envPtr;         /* Holds the resulting instructions. */
{
    int code;

    /*
     * Handle the common case: if there is a single text token, compile it
     * into an inline sequence of instructions.
     */
    
    envPtr->maxStackDepth = 0;
    if ((count == 1) && (tokenPtr->type == TCL_TOKEN_TEXT)) {
        code = TclCompileScript(interp, tokenPtr->start, tokenPtr->size,
                /*nested*/ 0, envPtr);
        return code;
    }

    /*
     * Multiple tokens or the single token involves substitutions. Emit
     * instructions to invoke the eval command procedure at runtime on the
     * result of evaluating the tokens.
     */

    code = TclCompileTokens(interp, tokenPtr, count, envPtr);
    if (code != TCL_OK) {
        return code;
    }
    TclEmitOpcode(INST_EVAL_STK, envPtr);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCompileExprWords --
 *
 *      Given an array of parse tokens representing one or more words that
 *      contain a Tcl expression, emit inline instructions to execute the
 *      expression. This procedure differs from TclCompileExpr in that it
 *      supports Tcl's two-level substitution semantics for expressions that
 *      appear as command words.
 *
 * Results:
 *      The return value is a standard Tcl result. If an error occurs, an
 *      error message is left in the interpreter's result.
 *      
 *      envPtr->maxStackDepth is updated with the maximum number of stack
 *      elements needed to execute the expression.
 *
 * Side effects:
 *      Instructions are added to envPtr to execute the expression.
 *
 *----------------------------------------------------------------------
 */

int
TclCompileExprWords(interp, tokenPtr, numWords, envPtr)
    Tcl_Interp *interp;         /* Used for error and status reporting. */
    Tcl_Token *tokenPtr;        /* Points to first in an array of word
                                 * tokens tokens for the expression to
                                 * compile inline. */
    int numWords;               /* Number of word tokens starting at
                                 * tokenPtr. Must be at least 1. Each word
                                 * token contains one or more subtokens. */
    CompileEnv *envPtr;         /* Holds the resulting instructions. */
{
    Tcl_Token *wordPtr;
    int maxDepth, range, numBytes, i, code;
    char *script;
    int saveExprIsJustVarRef = envPtr->exprIsJustVarRef;
    int saveExprIsComparison = envPtr->exprIsComparison;

    envPtr->maxStackDepth = 0;
    maxDepth = 0;
    range = -1;
    code = TCL_OK;

    /*
     * If the expression is a single word that doesn't require
     * substitutions, just compile it's string into inline instructions.
     */

    if ((numWords == 1) && (tokenPtr->type == TCL_TOKEN_SIMPLE_WORD)) {
        /*
         * Temporarily overwrite the character just after the end of the
         * string with a 0 byte.
         */

        script = tokenPtr[1].start;
        numBytes = tokenPtr[1].size;
        code = TclCompileExpr(interp, script, numBytes, envPtr);
        return code;
    }
   
    /*
     * Emit code to call the expr command proc at runtime. Concatenate the
     * (already substituted once) expr tokens with a space between each.
     */

    wordPtr = tokenPtr;
    for (i = 0;  i < numWords;  i++) {
        code = TclCompileTokens(interp, wordPtr+1, wordPtr->numComponents,
                envPtr);
        if (code != TCL_OK) {
            break;
        }
        if (i < (numWords - 1)) {
            TclEmitPush(TclRegisterLiteral(envPtr, " ", 1, /*onHeap*/ 0),
                    envPtr);
            maxDepth = TclMax((envPtr->maxStackDepth + 1), maxDepth);
        } else {
            maxDepth = TclMax(envPtr->maxStackDepth, maxDepth);
        }
        wordPtr += (wordPtr->numComponents + 1);
    }
    if (code == TCL_OK) {
        int concatItems = 2*numWords - 1;
        while (concatItems > 255) {
            TclEmitInstInt1(INST_CONCAT1, 255, envPtr);
            concatItems -= 254;
        }
        if (concatItems > 1) {
            TclEmitInstInt1(INST_CONCAT1, concatItems, envPtr);
        }
        TclEmitOpcode(INST_EXPR_STK, envPtr);
    }

    envPtr->exprIsJustVarRef = saveExprIsJustVarRef;
    envPtr->exprIsComparison = saveExprIsComparison;
    envPtr->maxStackDepth = maxDepth;
    return code;
}

/*
 *----------------------------------------------------------------------
 *
 * TclInitByteCodeObj --
 *
 *      Create a ByteCode structure and initialize it from a CompileEnv
 *      compilation environment structure. The ByteCode structure is
 *      smaller and contains just that information needed to execute
 *      the bytecode instructions resulting from compiling a Tcl script.
 *      The resulting structure is placed in the specified object.
 *
 * Results:
 *      A newly constructed ByteCode object is stored in the internal
 *      representation of the objPtr.
 *
 * Side effects:
 *      A single heap object is allocated to hold the new ByteCode structure
 *      and its code, object, command location, and aux data arrays. Note
 *      that "ownership" (i.e., the pointers to) the Tcl objects and aux
 *      data items will be handed over to the new ByteCode structure from
 *      the CompileEnv structure.
 *
 *----------------------------------------------------------------------
 */

void
TclInitByteCodeObj(objPtr, envPtr)
    Tcl_Obj *objPtr;             /* Points object that should be
                                  * initialized, and whose string rep
                                  * contains the source code. */
    register CompileEnv *envPtr; /* Points to the CompileEnv structure from
                                  * which to create a ByteCode structure. */
{
    register ByteCode *codePtr;
    size_t codeBytes, objArrayBytes, exceptArrayBytes, cmdLocBytes;
    size_t auxDataArrayBytes, structureSize;
    register unsigned char *p;
    unsigned char *nextPtr;
    int numLitObjects = envPtr->literalArrayNext;
    Namespace *namespacePtr;
    int i;
    Interp *iPtr;

    iPtr = envPtr->iPtr;

    codeBytes = (envPtr->codeNext - envPtr->codeStart);
    objArrayBytes = (envPtr->literalArrayNext * sizeof(Tcl_Obj *));
    exceptArrayBytes = (envPtr->exceptArrayNext * sizeof(ExceptionRange));
    auxDataArrayBytes = (envPtr->auxDataArrayNext * sizeof(AuxData));
    cmdLocBytes = GetCmdLocEncodingSize(envPtr);
    
    /*
     * Compute the total number of bytes needed for this bytecode.
     */

    structureSize = sizeof(ByteCode);
    structureSize += TCL_ALIGN(codeBytes);        /* align object array */
    structureSize += TCL_ALIGN(objArrayBytes);    /* align exc range arr */
    structureSize += TCL_ALIGN(exceptArrayBytes); /* align AuxData array */
    structureSize += auxDataArrayBytes;
    structureSize += cmdLocBytes;

    if (envPtr->iPtr->varFramePtr != NULL) {
        namespacePtr = envPtr->iPtr->varFramePtr->nsPtr;
    } else {
        namespacePtr = envPtr->iPtr->globalNsPtr;
    }
    
    p = (unsigned char *) ckalloc((size_t) structureSize);
    codePtr = (ByteCode *) p;
    codePtr->interpHandle = TclHandlePreserve(iPtr->handle);
    codePtr->compileEpoch = iPtr->compileEpoch;
    codePtr->nsPtr = namespacePtr;
    codePtr->nsEpoch = namespacePtr->resolverEpoch;
    codePtr->refCount = 1;
    codePtr->flags = 0;
    codePtr->source = envPtr->source;
    codePtr->procPtr = envPtr->procPtr;

    codePtr->numCommands = envPtr->numCommands;
    codePtr->numSrcBytes = envPtr->numSrcBytes;
    codePtr->numCodeBytes = codeBytes;
    codePtr->numLitObjects = numLitObjects;
    codePtr->numExceptRanges = envPtr->exceptArrayNext;
    codePtr->numAuxDataItems = envPtr->auxDataArrayNext;
    codePtr->numCmdLocBytes = cmdLocBytes;
    codePtr->maxExceptDepth = envPtr->maxExceptDepth;
    codePtr->maxStackDepth = envPtr->maxStackDepth;
    
    p += sizeof(ByteCode);
    codePtr->codeStart = p;
    memcpy((VOID *) p, (VOID *) envPtr->codeStart, (size_t) codeBytes);
    
    p += TCL_ALIGN(codeBytes);        /* align object array */
    codePtr->objArrayPtr = (Tcl_Obj **) p;
    for (i = 0;  i < numLitObjects;  i++) {
        codePtr->objArrayPtr[i] = envPtr->literalArrayPtr[i].objPtr;
    }

    p += TCL_ALIGN(objArrayBytes);    /* align exception range array */
    if (exceptArrayBytes > 0) {
        codePtr->exceptArrayPtr = (ExceptionRange *) p;
        memcpy((VOID *) p, (VOID *) envPtr->exceptArrayPtr,
                (size_t) exceptArrayBytes);
    } else {
        codePtr->exceptArrayPtr = NULL;
    }
    
    p += TCL_ALIGN(exceptArrayBytes); /* align AuxData array */
    if (auxDataArrayBytes > 0) {
        codePtr->auxDataArrayPtr = (AuxData *) p;
        memcpy((VOID *) p, (VOID *) envPtr->auxDataArrayPtr,
                (size_t) auxDataArrayBytes);
    } else {
        codePtr->auxDataArrayPtr = NULL;
    }

    p += auxDataArrayBytes;
    nextPtr = EncodeCmdLocMap(envPtr, codePtr, (unsigned char *) p);
#ifdef TCL_COMPILE_DEBUG
    if (((size_t)(nextPtr - p)) != cmdLocBytes) {       
        panic("TclInitByteCodeObj: encoded cmd location bytes %d != expected size %d\n", (nextPtr - p), cmdLocBytes);
    }
#endif
    
    /*
     * Record various compilation-related statistics about the new ByteCode
     * structure. Don't include overhead for statistics-related fields.
     */

#ifdef TCL_COMPILE_STATS
    codePtr->structureSize = structureSize
            - (sizeof(size_t) + sizeof(Tcl_Time));
    TclpGetTime(&(codePtr->createTime));
    
    RecordByteCodeStats(codePtr);
#endif /* TCL_COMPILE_STATS */
    
    /*
     * Free the old internal rep then convert the object to a
     * bytecode object by making its internal rep point to the just
     * compiled ByteCode.
     */
            
    if ((objPtr->typePtr != NULL) &&
            (objPtr->typePtr->freeIntRepProc != NULL)) {
        (*objPtr->typePtr->freeIntRepProc)(objPtr);
    }
    objPtr->internalRep.otherValuePtr = (VOID *) codePtr;
    objPtr->typePtr = &tclByteCodeType;
}

/*
 *----------------------------------------------------------------------
 *
 * LogCompilationInfo --
 *
 *      This procedure is invoked after an error occurs during compilation.
 *      It adds information to the "errorInfo" variable to describe the
 *      command that was being compiled when the error occurred.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Information about the command is added to errorInfo and the
 *      line number stored internally in the interpreter is set.  If this
 *      is the first call to this procedure or Tcl_AddObjErrorInfo since
 *      an error occurred, then old information in errorInfo is
 *      deleted.
 *
 *----------------------------------------------------------------------
 */

static void
LogCompilationInfo(interp, script, command, length)
    Tcl_Interp *interp;         /* Interpreter in which to log the
                                 * information. */
    char *script;               /* First character in script containing
                                 * command (must be <= command). */
    char *command;              /* First character in command that
                                 * generated the error. */
    int length;                 /* Number of bytes in command (-1 means
                                 * use all bytes up to first null byte). */
{
    char buffer[200];
    register char *p;
    char *ellipsis = "";
    Interp *iPtr = (Interp *) interp;

    if (iPtr->flags & ERR_ALREADY_LOGGED) {
        /*
         * Someone else has already logged error information for this
         * command; we shouldn't add anything more.
         */

        return;
    }

    /*
     * Compute the line number where the error occurred.
     */

    iPtr->errorLine = 1;
    for (p = script; p != command; p++) {
        if (*p == '\n') {
            iPtr->errorLine++;
        }
    }

    /*
     * Create an error message to add to errorInfo, including up to a
     * maximum number of characters of the command.
     */

    if (length < 0) {
        length = strlen(command);
    }
    if (length > 150) {
        length = 150;
        ellipsis = "...";
    }
    sprintf(buffer, "\n    while compiling\n\"%.*s%s\"",
            length, command, ellipsis);
    Tcl_AddObjErrorInfo(interp, buffer, -1);
}

/*
 *----------------------------------------------------------------------
 *
 * TclFindCompiledLocal --
 *
 *      This procedure is called at compile time to look up and optionally
 *      allocate an entry ("slot") for a variable in a procedure's array of
 *      local variables. If the variable's name is NULL, a new temporary
 *      variable is always created. (Such temporary variables can only be
 *      referenced using their slot index.)
 *
 * Results:
 *      If create is 0 and the name is non-NULL, then if the variable is
 *      found, the index of its entry in the procedure's array of local
 *      variables is returned; otherwise -1 is returned. If name is NULL,
 *      the index of a new temporary variable is returned. Finally, if
 *      create is 1 and name is non-NULL, the index of a new entry is
 *      returned.
 *
 * Side effects:
 *      Creates and registers a new local variable if create is 1 and
 *      the variable is unknown, or if the name is NULL.
 *
 *----------------------------------------------------------------------
 */

int
TclFindCompiledLocal(name, nameBytes, create, flags, procPtr)
    register char *name;        /* Points to first character of the name of
                                 * a scalar or array variable. If NULL, a
                                 * temporary var should be created. */
    int nameBytes;              /* Number of bytes in the name. */
    int create;                 /* If 1, allocate a local frame entry for
                                 * the variable if it is new. */
    int flags;                  /* Flag bits for the compiled local if
                                 * created. Only VAR_SCALAR, VAR_ARRAY, and
                                 * VAR_LINK make sense. */
    register Proc *procPtr;     /* Points to structure describing procedure
                                 * containing the variable reference. */
{
    register CompiledLocal *localPtr;
    int localVar = -1;
    register int i;

    /*
     * If not creating a temporary, does a local variable of the specified
     * name already exist?
     */

    if (name != NULL) { 
        int localCt = procPtr->numCompiledLocals;
        localPtr = procPtr->firstLocalPtr;
        for (i = 0;  i < localCt;  i++) {
            if (!TclIsVarTemporary(localPtr)) {
                char *localName = localPtr->name;
                if ((nameBytes == localPtr->nameLength)
                        && (strncmp(name, localName, (unsigned) nameBytes) == 0)) {
                    return i;
                }
            }
            localPtr = localPtr->nextPtr;
        }
    }

    /*
     * Create a new variable if appropriate.
     */
    
    if (create || (name == NULL)) {
        localVar = procPtr->numCompiledLocals;
        localPtr = (CompiledLocal *) ckalloc((unsigned) 
                (sizeof(CompiledLocal) - sizeof(localPtr->name)
                + nameBytes+1));
        if (procPtr->firstLocalPtr == NULL) {
            procPtr->firstLocalPtr = procPtr->lastLocalPtr = localPtr;
        } else {
            procPtr->lastLocalPtr->nextPtr = localPtr;
            procPtr->lastLocalPtr = localPtr;
        }
        localPtr->nextPtr = NULL;
        localPtr->nameLength = nameBytes;
        localPtr->frameIndex = localVar;
        localPtr->flags = flags;
        if (name == NULL) {
            localPtr->flags |= VAR_TEMPORARY;
        }
        localPtr->defValuePtr = NULL;
        localPtr->resolveInfo = NULL;

        if (name != NULL) {
            memcpy((VOID *) localPtr->name, (VOID *) name,
                    (size_t) nameBytes);
        }
        localPtr->name[nameBytes] = '\0';
        procPtr->numCompiledLocals++;
    }
    return localVar;
}

/*
 *----------------------------------------------------------------------
 *
 * TclInitCompiledLocals --
 *
 *      This routine is invoked in order to initialize the compiled
 *      locals table for a new call frame.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      May invoke various name resolvers in order to determine which
 *      variables are being referenced at runtime.
 *
 *----------------------------------------------------------------------
 */

void
TclInitCompiledLocals(interp, framePtr, nsPtr)
    Tcl_Interp *interp;         /* Current interpreter. */
    CallFrame *framePtr;        /* Call frame to initialize. */
    Namespace *nsPtr;           /* Pointer to current namespace. */
{
    register CompiledLocal *localPtr;
    Interp *iPtr = (Interp*) interp;
    Tcl_ResolvedVarInfo *vinfo, *resVarInfo;
    Var *varPtr = framePtr->compiledLocals;
    Var *resolvedVarPtr;
    ResolverScheme *resPtr;
    int result;

    /*
     * Initialize the array of local variables stored in the call frame.
     * Some variables may have special resolution rules.  In that case,
     * we call their "resolver" procs to get our hands on the variable,
     * and we make the compiled local a link to the real variable.
     */

    for (localPtr = framePtr->procPtr->firstLocalPtr;
         localPtr != NULL;
         localPtr = localPtr->nextPtr) {

        /*
         * Check to see if this local is affected by namespace or
         * interp resolvers.  The resolver to use is cached for the
         * next invocation of the procedure.
         */

        if (!(localPtr->flags & (VAR_ARGUMENT|VAR_TEMPORARY|VAR_RESOLVED))
                && (nsPtr->compiledVarResProc || iPtr->resolverPtr)) {
            resPtr = iPtr->resolverPtr;

            if (nsPtr->compiledVarResProc) {
                result = (*nsPtr->compiledVarResProc)(nsPtr->interp,
                        localPtr->name, localPtr->nameLength,
                        (Tcl_Namespace *) nsPtr, &vinfo);
            } else {
                result = TCL_CONTINUE;
            }

            while ((result == TCL_CONTINUE) && resPtr) {
                if (resPtr->compiledVarResProc) {
                    result = (*resPtr->compiledVarResProc)(nsPtr->interp,
                            localPtr->name, localPtr->nameLength,
                            (Tcl_Namespace *) nsPtr, &vinfo);
                }
                resPtr = resPtr->nextPtr;
            }
            if (result == TCL_OK) {
                localPtr->resolveInfo = vinfo;
                localPtr->flags |= VAR_RESOLVED;
            }
        }

        /*
         * Now invoke the resolvers to determine the exact variables that
         * should be used.
         */

        resVarInfo = localPtr->resolveInfo;
        resolvedVarPtr = NULL;

        if (resVarInfo && resVarInfo->fetchProc) {
            resolvedVarPtr = (Var*) (*resVarInfo->fetchProc)(interp,
                    resVarInfo);
        }

        if (resolvedVarPtr) {
            varPtr->name = localPtr->name; /* will be just '\0' if temp var */
            varPtr->nsPtr = NULL;
            varPtr->hPtr = NULL;
            varPtr->refCount = 0;
            varPtr->tracePtr = NULL;
            varPtr->searchPtr = NULL;
            varPtr->flags = 0;
            TclSetVarLink(varPtr);
            varPtr->value.linkPtr = resolvedVarPtr;
            resolvedVarPtr->refCount++;
        } else {
            varPtr->value.objPtr = NULL;
            varPtr->name = localPtr->name; /* will be just '\0' if temp var */
            varPtr->nsPtr = NULL;
            varPtr->hPtr = NULL;
            varPtr->refCount = 0;
            varPtr->tracePtr = NULL;
            varPtr->searchPtr = NULL;
            varPtr->flags = (localPtr->flags | VAR_UNDEFINED);
        }
        varPtr++;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclExpandCodeArray --
 *
 *      Procedure that uses malloc to allocate more storage for a
 *      CompileEnv's code array.
 *
 * Results:
 *      None. 
 *
 * Side effects:
 *      The byte code array in *envPtr is reallocated to a new array of
 *      double the size, and if envPtr->mallocedCodeArray is non-zero the
 *      old array is freed. Byte codes are copied from the old array to the
 *      new one.
 *
 *----------------------------------------------------------------------
 */

void
TclExpandCodeArray(envPtr)
    CompileEnv *envPtr;         /* Points to the CompileEnv whose code array
                                 * must be enlarged. */
{
    /*
     * envPtr->codeNext is equal to envPtr->codeEnd. The currently defined
     * code bytes are stored between envPtr->codeStart and
     * (envPtr->codeNext - 1) [inclusive].
     */
    
    size_t currBytes = (envPtr->codeNext - envPtr->codeStart);
    size_t newBytes  = 2*(envPtr->codeEnd  - envPtr->codeStart);
    unsigned char *newPtr = (unsigned char *) ckalloc((unsigned) newBytes);

    /*
     * Copy from old code array to new, free old code array if needed, and
     * mark new code array as malloced.
     */
 
    memcpy((VOID *) newPtr, (VOID *) envPtr->codeStart, currBytes);
    if (envPtr->mallocedCodeArray) {
        ckfree((char *) envPtr->codeStart);
    }
    envPtr->codeStart = newPtr;
    envPtr->codeNext = (newPtr + currBytes);
    envPtr->codeEnd  = (newPtr + newBytes);
    envPtr->mallocedCodeArray = 1;
}

/*
 *----------------------------------------------------------------------
 *
 * EnterCmdStartData --
 *
 *      Registers the starting source and bytecode location of a
 *      command. This information is used at runtime to map between
 *      instruction pc and source locations.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Inserts source and code location information into the compilation
 *      environment envPtr for the command at index cmdIndex. The
 *      compilation environment's CmdLocation array is grown if necessary.
 *
 *----------------------------------------------------------------------
 */

static void
EnterCmdStartData(envPtr, cmdIndex, srcOffset, codeOffset)
    CompileEnv *envPtr;         /* Points to the compilation environment
                                 * structure in which to enter command
                                 * location information. */
    int cmdIndex;               /* Index of the command whose start data
                                 * is being set. */
    int srcOffset;              /* Offset of first char of the command. */
    int codeOffset;             /* Offset of first byte of command code. */
{
    CmdLocation *cmdLocPtr;
    
    if ((cmdIndex < 0) || (cmdIndex >= envPtr->numCommands)) {
        panic("EnterCmdStartData: bad command index %d\n", cmdIndex);
    }
    
    if (cmdIndex >= envPtr->cmdMapEnd) {
        /*
         * Expand the command location array by allocating more storage from
         * the heap. The currently allocated CmdLocation entries are stored
         * from cmdMapPtr[0] up to cmdMapPtr[envPtr->cmdMapEnd] (inclusive).
         */

        size_t currElems = envPtr->cmdMapEnd;
        size_t newElems  = 2*currElems;
        size_t currBytes = currElems * sizeof(CmdLocation);
        size_t newBytes  = newElems  * sizeof(CmdLocation);
        CmdLocation *newPtr = (CmdLocation *) ckalloc((unsigned) newBytes);
        
        /*
         * Copy from old command location array to new, free old command
         * location array if needed, and mark new array as malloced.
         */
        
        memcpy((VOID *) newPtr, (VOID *) envPtr->cmdMapPtr, currBytes);
        if (envPtr->mallocedCmdMap) {
            ckfree((char *) envPtr->cmdMapPtr);
        }
        envPtr->cmdMapPtr = (CmdLocation *) newPtr;
        envPtr->cmdMapEnd = newElems;
        envPtr->mallocedCmdMap = 1;
    }

    if (cmdIndex > 0) {
        if (codeOffset < envPtr->cmdMapPtr[cmdIndex-1].codeOffset) {
            panic("EnterCmdStartData: cmd map not sorted by code offset");
        }
    }

    cmdLocPtr = &(envPtr->cmdMapPtr[cmdIndex]);
    cmdLocPtr->codeOffset = codeOffset;
    cmdLocPtr->srcOffset = srcOffset;
    cmdLocPtr->numSrcBytes = -1;
    cmdLocPtr->numCodeBytes = -1;
}

/*
 *----------------------------------------------------------------------
 *
 * EnterCmdExtentData --
 *
 *      Registers the source and bytecode length for a command. This
 *      information is used at runtime to map between instruction pc and
 *      source locations.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Inserts source and code length information into the compilation
 *      environment envPtr for the command at index cmdIndex. Starting
 *      source and bytecode information for the command must already
 *      have been registered.
 *
 *----------------------------------------------------------------------
 */

static void
EnterCmdExtentData(envPtr, cmdIndex, numSrcBytes, numCodeBytes)
    CompileEnv *envPtr;         /* Points to the compilation environment
                                 * structure in which to enter command
                                 * location information. */
    int cmdIndex;               /* Index of the command whose source and
                                 * code length data is being set. */
    int numSrcBytes;            /* Number of command source chars. */
    int numCodeBytes;           /* Offset of last byte of command code. */
{
    CmdLocation *cmdLocPtr;

    if ((cmdIndex < 0) || (cmdIndex >= envPtr->numCommands)) {
        panic("EnterCmdExtentData: bad command index %d\n", cmdIndex);
    }
    
    if (cmdIndex > envPtr->cmdMapEnd) {
        panic("EnterCmdExtentData: missing start data for command %d\n",
                cmdIndex);
    }

    cmdLocPtr = &(envPtr->cmdMapPtr[cmdIndex]);
    cmdLocPtr->numSrcBytes = numSrcBytes;
    cmdLocPtr->numCodeBytes = numCodeBytes;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCreateExceptRange --
 *
 *      Procedure that allocates and initializes a new ExceptionRange
 *      structure of the specified kind in a CompileEnv.
 *
 * Results:
 *      Returns the index for the newly created ExceptionRange.
 *
 * Side effects:
 *      If there is not enough room in the CompileEnv's ExceptionRange
 *      array, the array in expanded: a new array of double the size is
 *      allocated, if envPtr->mallocedExceptArray is non-zero the old
 *      array is freed, and ExceptionRange entries are copied from the old
 *      array to the new one.
 *
 *----------------------------------------------------------------------
 */

int
TclCreateExceptRange(type, envPtr)
    ExceptionRangeType type;    /* The kind of ExceptionRange desired. */
    register CompileEnv *envPtr;/* Points to CompileEnv for which to
                                 * create a new ExceptionRange structure. */
{
    register ExceptionRange *rangePtr;
    int index = envPtr->exceptArrayNext;
    
    if (index >= envPtr->exceptArrayEnd) {
        /*
         * Expand the ExceptionRange array. The currently allocated entries
         * are stored between elements 0 and (envPtr->exceptArrayNext - 1)
         * [inclusive].
         */
        
        size_t currBytes =
                envPtr->exceptArrayNext * sizeof(ExceptionRange);
        int newElems = 2*envPtr->exceptArrayEnd;
        size_t newBytes = newElems * sizeof(ExceptionRange);
        ExceptionRange *newPtr = (ExceptionRange *)
                ckalloc((unsigned) newBytes);
        
        /*
         * Copy from old ExceptionRange array to new, free old
         * ExceptionRange array if needed, and mark the new ExceptionRange
         * array as malloced.
         */
        
        memcpy((VOID *) newPtr, (VOID *) envPtr->exceptArrayPtr,
                currBytes);
        if (envPtr->mallocedExceptArray) {
            ckfree((char *) envPtr->exceptArrayPtr);
        }
        envPtr->exceptArrayPtr = (ExceptionRange *) newPtr;
        envPtr->exceptArrayEnd = newElems;
        envPtr->mallocedExceptArray = 1;
    }
    envPtr->exceptArrayNext++;
    
    rangePtr = &(envPtr->exceptArrayPtr[index]);
    rangePtr->type = type;
    rangePtr->nestingLevel = envPtr->exceptDepth;
    rangePtr->codeOffset = -1;
    rangePtr->numCodeBytes = -1;
    rangePtr->breakOffset = -1;
    rangePtr->continueOffset = -1;
    rangePtr->catchOffset = -1;
    return index;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCreateAuxData --
 *
 *      Procedure that allocates and initializes a new AuxData structure in
 *      a CompileEnv's array of compilation auxiliary data records. These
 *      AuxData records hold information created during compilation by
 *      CompileProcs and used by instructions during execution.
 *
 * Results:
 *      Returns the index for the newly created AuxData structure.
 *
 * Side effects:
 *      If there is not enough room in the CompileEnv's AuxData array,
 *      the AuxData array in expanded: a new array of double the size
 *      is allocated, if envPtr->mallocedAuxDataArray is non-zero
 *      the old array is freed, and AuxData entries are copied from
 *      the old array to the new one.
 *
 *----------------------------------------------------------------------
 */

int
TclCreateAuxData(clientData, typePtr, envPtr)
    ClientData clientData;      /* The compilation auxiliary data to store
                                 * in the new aux data record. */
    AuxDataType *typePtr;       /* Pointer to the type to attach to this AuxData */
    register CompileEnv *envPtr;/* Points to the CompileEnv for which a new
                                 * aux data structure is to be allocated. */
{
    int index;                  /* Index for the new AuxData structure. */
    register AuxData *auxDataPtr;
                                /* Points to the new AuxData structure */
    
    index = envPtr->auxDataArrayNext;
    if (index >= envPtr->auxDataArrayEnd) {
        /*
         * Expand the AuxData array. The currently allocated entries are
         * stored between elements 0 and (envPtr->auxDataArrayNext - 1)
         * [inclusive].
         */
        
        size_t currBytes = envPtr->auxDataArrayNext * sizeof(AuxData);
        int newElems = 2*envPtr->auxDataArrayEnd;
        size_t newBytes = newElems * sizeof(AuxData);
        AuxData *newPtr = (AuxData *) ckalloc((unsigned) newBytes);
        
        /*
         * Copy from old AuxData array to new, free old AuxData array if
         * needed, and mark the new AuxData array as malloced.
         */
        
        memcpy((VOID *) newPtr, (VOID *) envPtr->auxDataArrayPtr,
                currBytes);
        if (envPtr->mallocedAuxDataArray) {
            ckfree((char *) envPtr->auxDataArrayPtr);
        }
        envPtr->auxDataArrayPtr = newPtr;
        envPtr->auxDataArrayEnd = newElems;
        envPtr->mallocedAuxDataArray = 1;
    }
    envPtr->auxDataArrayNext++;
    
    auxDataPtr = &(envPtr->auxDataArrayPtr[index]);
    auxDataPtr->clientData = clientData;
    auxDataPtr->type = typePtr;
    return index;
}

/*
 *----------------------------------------------------------------------
 *
 * TclInitJumpFixupArray --
 *
 *      Initializes a JumpFixupArray structure to hold some number of
 *      jump fixup entries.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The JumpFixupArray structure is initialized.
 *
 *----------------------------------------------------------------------
 */

void
TclInitJumpFixupArray(fixupArrayPtr)
    register JumpFixupArray *fixupArrayPtr;
                                 /* Points to the JumpFixupArray structure
                                  * to initialize. */
{
    fixupArrayPtr->fixup = fixupArrayPtr->staticFixupSpace;
    fixupArrayPtr->next = 0;
    fixupArrayPtr->end = (JUMPFIXUP_INIT_ENTRIES - 1);
    fixupArrayPtr->mallocedArray = 0;
}

/*
 *----------------------------------------------------------------------
 *
 * TclExpandJumpFixupArray --
 *
 *      Procedure that uses malloc to allocate more storage for a
 *      jump fixup array.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The jump fixup array in *fixupArrayPtr is reallocated to a new array
 *      of double the size, and if fixupArrayPtr->mallocedArray is non-zero
 *      the old array is freed. Jump fixup structures are copied from the
 *      old array to the new one.
 *
 *----------------------------------------------------------------------
 */

void
TclExpandJumpFixupArray(fixupArrayPtr)
    register JumpFixupArray *fixupArrayPtr;
                                 /* Points to the JumpFixupArray structure
                                  * to enlarge. */
{
    /*
     * The currently allocated jump fixup entries are stored from fixup[0]
     * up to fixup[fixupArrayPtr->fixupNext] (*not* inclusive). We assume
     * fixupArrayPtr->fixupNext is equal to fixupArrayPtr->fixupEnd.
     */

    size_t currBytes = fixupArrayPtr->next * sizeof(JumpFixup);
    int newElems = 2*(fixupArrayPtr->end + 1);
    size_t newBytes = newElems * sizeof(JumpFixup);
    JumpFixup *newPtr = (JumpFixup *) ckalloc((unsigned) newBytes);

    /*
     * Copy from the old array to new, free the old array if needed,
     * and mark the new array as malloced.
     */
 
    memcpy((VOID *) newPtr, (VOID *) fixupArrayPtr->fixup, currBytes);
    if (fixupArrayPtr->mallocedArray) {
        ckfree((char *) fixupArrayPtr->fixup);
    }
    fixupArrayPtr->fixup = (JumpFixup *) newPtr;
    fixupArrayPtr->end = newElems;
    fixupArrayPtr->mallocedArray = 1;
}

/*
 *----------------------------------------------------------------------
 *
 * TclFreeJumpFixupArray --
 *
 *      Free any storage allocated in a jump fixup array structure.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Allocated storage in the JumpFixupArray structure is freed.
 *
 *----------------------------------------------------------------------
 */

void
TclFreeJumpFixupArray(fixupArrayPtr)
    register JumpFixupArray *fixupArrayPtr;
                                 /* Points to the JumpFixupArray structure
                                  * to free. */
{
    if (fixupArrayPtr->mallocedArray) {
        ckfree((char *) fixupArrayPtr->fixup);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclEmitForwardJump --
 *
 *      Procedure to emit a two-byte forward jump of kind "jumpType". Since
 *      the jump may later have to be grown to five bytes if the jump target
 *      is more than, say, 127 bytes away, this procedure also initializes a
 *      JumpFixup record with information about the jump. 
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The JumpFixup record pointed to by "jumpFixupPtr" is initialized
 *      with information needed later if the jump is to be grown. Also,
 *      a two byte jump of the designated type is emitted at the current
 *      point in the bytecode stream.
 *
 *----------------------------------------------------------------------
 */

void
TclEmitForwardJump(envPtr, jumpType, jumpFixupPtr)
    CompileEnv *envPtr;         /* Points to the CompileEnv structure that
                                 * holds the resulting instruction. */
    TclJumpType jumpType;       /* Indicates the kind of jump: if true or
                                 * false or unconditional. */
    JumpFixup *jumpFixupPtr;    /* Points to the JumpFixup structure to
                                 * initialize with information about this
                                 * forward jump. */
{
    /*
     * Initialize the JumpFixup structure:
     *    - codeOffset is offset of first byte of jump below
     *    - cmdIndex is index of the command after the current one
     *    - exceptIndex is the index of the first ExceptionRange after
     *      the current one.
     */
    
    jumpFixupPtr->jumpType = jumpType;
    jumpFixupPtr->codeOffset = (envPtr->codeNext - envPtr->codeStart);
    jumpFixupPtr->cmdIndex = envPtr->numCommands;
    jumpFixupPtr->exceptIndex = envPtr->exceptArrayNext;
    
    switch (jumpType) {
    case TCL_UNCONDITIONAL_JUMP:
        TclEmitInstInt1(INST_JUMP1, 0, envPtr);
        break;
    case TCL_TRUE_JUMP:
        TclEmitInstInt1(INST_JUMP_TRUE1, 0, envPtr);
        break;
    default:
        TclEmitInstInt1(INST_JUMP_FALSE1, 0, envPtr);
        break;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclFixupForwardJump --
 *
 *      Procedure that updates a previously-emitted forward jump to jump
 *      a specified number of bytes, "jumpDist". If necessary, the jump is
 *      grown from two to five bytes; this is done if the jump distance is
 *      greater than "distThreshold" (normally 127 bytes). The jump is
 *      described by a JumpFixup record previously initialized by
 *      TclEmitForwardJump.
 *
 * Results:
 *      1 if the jump was grown and subsequent instructions had to be moved;
 *      otherwise 0. This result is returned to allow callers to update
 *      any additional code offsets they may hold.
 *
 * Side effects:
 *      The jump may be grown and subsequent instructions moved. If this
 *      happens, the code offsets for any commands and any ExceptionRange
 *      records between the jump and the current code address will be
 *      updated to reflect the moved code. Also, the bytecode instruction
 *      array in the CompileEnv structure may be grown and reallocated.
 *
 *----------------------------------------------------------------------
 */

int
TclFixupForwardJump(envPtr, jumpFixupPtr, jumpDist, distThreshold)
    CompileEnv *envPtr;         /* Points to the CompileEnv structure that
                                 * holds the resulting instruction. */
    JumpFixup *jumpFixupPtr;    /* Points to the JumpFixup structure that
                                 * describes the forward jump. */
    int jumpDist;               /* Jump distance to set in jump
                                 * instruction. */
    int distThreshold;          /* Maximum distance before the two byte
                                 * jump is grown to five bytes. */
{
    unsigned char *jumpPc, *p;
    int firstCmd, lastCmd, firstRange, lastRange, k;
    unsigned int numBytes;
    
    if (jumpDist <= distThreshold) {
        jumpPc = (envPtr->codeStart + jumpFixupPtr->codeOffset);
        switch (jumpFixupPtr->jumpType) {
        case TCL_UNCONDITIONAL_JUMP:
            TclUpdateInstInt1AtPc(INST_JUMP1, jumpDist, jumpPc);
            break;
        case TCL_TRUE_JUMP:
            TclUpdateInstInt1AtPc(INST_JUMP_TRUE1, jumpDist, jumpPc);
            break;
        default:
            TclUpdateInstInt1AtPc(INST_JUMP_FALSE1, jumpDist, jumpPc);
            break;
        }
        return 0;
    }

    /*
     * We must grow the jump then move subsequent instructions down.
     * Note that if we expand the space for generated instructions,
     * code addresses might change; be careful about updating any of
     * these addresses held in variables.
     */
    
    if ((envPtr->codeNext + 3) > envPtr->codeEnd) {
        TclExpandCodeArray(envPtr);
    }
    jumpPc = (envPtr->codeStart + jumpFixupPtr->codeOffset);
    for (numBytes = envPtr->codeNext-jumpPc-2, p = jumpPc+2+numBytes-1;
            numBytes > 0;  numBytes--, p--) {
        p[3] = p[0];
    }
    envPtr->codeNext += 3;
    jumpDist += 3;
    switch (jumpFixupPtr->jumpType) {
    case TCL_UNCONDITIONAL_JUMP:
        TclUpdateInstInt4AtPc(INST_JUMP4, jumpDist, jumpPc);
        break;
    case TCL_TRUE_JUMP:
        TclUpdateInstInt4AtPc(INST_JUMP_TRUE4, jumpDist, jumpPc);
        break;
    default:
        TclUpdateInstInt4AtPc(INST_JUMP_FALSE4, jumpDist, jumpPc);
        break;
    }
    
    /*
     * Adjust the code offsets for any commands and any ExceptionRange
     * records between the jump and the current code address.
     */
    
    firstCmd = jumpFixupPtr->cmdIndex;
    lastCmd  = (envPtr->numCommands - 1);
    if (firstCmd < lastCmd) {
        for (k = firstCmd;  k <= lastCmd;  k++) {
            (envPtr->cmdMapPtr[k]).codeOffset += 3;
        }
    }
    
    firstRange = jumpFixupPtr->exceptIndex;
    lastRange  = (envPtr->exceptArrayNext - 1);
    for (k = firstRange;  k <= lastRange;  k++) {
        ExceptionRange *rangePtr = &(envPtr->exceptArrayPtr[k]);
        rangePtr->codeOffset += 3;
        
        switch (rangePtr->type) {
        case LOOP_EXCEPTION_RANGE:
            rangePtr->breakOffset += 3;
            if (rangePtr->continueOffset != -1) {
                rangePtr->continueOffset += 3;
            }
            break;
        case CATCH_EXCEPTION_RANGE:
            rangePtr->catchOffset += 3;
            break;
        default:
            panic("TclFixupForwardJump: bad ExceptionRange type %d\n",
                    rangePtr->type);
        }
    }
    return 1;                   /* the jump was grown */
}

/*
 *----------------------------------------------------------------------
 *
 * TclGetInstructionTable --
 *
 *  Returns a pointer to the table describing Tcl bytecode instructions.
 *  This procedure is defined so that clients can access the pointer from
 *  outside the TCL DLLs.
 *
 * Results:
 *      Returns a pointer to the global instruction table, same as the
 *      expression (&instructionTable[0]).
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

InstructionDesc *
TclGetInstructionTable()
{
    return &instructionTable[0];
}

/*
 *--------------------------------------------------------------
 *
 * TclRegisterAuxDataType --
 *
 *      This procedure is called to register a new AuxData type
 *      in the table of all AuxData types supported by Tcl.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      The type is registered in the AuxData type table. If there was already
 *      a type with the same name as in typePtr, it is replaced with the
 *      new type.
 *
 *--------------------------------------------------------------
 */

void
TclRegisterAuxDataType(typePtr)
    AuxDataType *typePtr;       /* Information about object type;
                             * storage must be statically
                             * allocated (must live forever). */
{
    register Tcl_HashEntry *hPtr;
    int new;

    Tcl_MutexLock(&tableMutex);
    if (!auxDataTypeTableInitialized) {
        TclInitAuxDataTypeTable();
    }

    /*
     * If there's already a type with the given name, remove it.
     */

    hPtr = Tcl_FindHashEntry(&auxDataTypeTable, typePtr->name);
    if (hPtr != (Tcl_HashEntry *) NULL) {
        Tcl_DeleteHashEntry(hPtr);
    }

    /*
     * Now insert the new object type.
     */

    hPtr = Tcl_CreateHashEntry(&auxDataTypeTable, typePtr->name, &new);
    if (new) {
        Tcl_SetHashValue(hPtr, typePtr);
    }
    Tcl_MutexUnlock(&tableMutex);
}

/*
 *----------------------------------------------------------------------
 *
 * TclGetAuxDataType --
 *
 *      This procedure looks up an Auxdata type by name.
 *
 * Results:
 *      If an AuxData type with name matching "typeName" is found, a pointer
 *      to its AuxDataType structure is returned; otherwise, NULL is returned.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

AuxDataType *
TclGetAuxDataType(typeName)
    char *typeName;             /* Name of AuxData type to look up. */
{
    register Tcl_HashEntry *hPtr;
    AuxDataType *typePtr = NULL;

    Tcl_MutexLock(&tableMutex);
    if (!auxDataTypeTableInitialized) {
        TclInitAuxDataTypeTable();
    }

    hPtr = Tcl_FindHashEntry(&auxDataTypeTable, typeName);
    if (hPtr != (Tcl_HashEntry *) NULL) {
        typePtr = (AuxDataType *) Tcl_GetHashValue(hPtr);
    }
    Tcl_MutexUnlock(&tableMutex);

    return typePtr;
}

/*
 *--------------------------------------------------------------
 *
 * TclInitAuxDataTypeTable --
 *
 *      This procedure is invoked to perform once-only initialization of
 *      the AuxData type table. It also registers the AuxData types defined in 
 *      this file.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Initializes the table of defined AuxData types "auxDataTypeTable" with
 *      builtin AuxData types defined in this file.
 *
 *--------------------------------------------------------------
 */

void
TclInitAuxDataTypeTable()
{
    /*
     * The table mutex must already be held before this routine is invoked.
     */

    auxDataTypeTableInitialized = 1;
    Tcl_InitHashTable(&auxDataTypeTable, TCL_STRING_KEYS);

    /*
     * There is only one AuxData type at this time, so register it here.
     */

    TclRegisterAuxDataType(&tclForeachInfoType);
}

/*
 *----------------------------------------------------------------------
 *
 * TclFinalizeAuxDataTypeTable --
 *
 *      This procedure is called by Tcl_Finalize after all exit handlers
 *      have been run to free up storage associated with the table of AuxData
 *      types.  This procedure is called by TclFinalizeExecution() which
 *      is called by Tcl_Finalize().
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Deletes all entries in the hash table of AuxData types.
 *
 *----------------------------------------------------------------------
 */

void
TclFinalizeAuxDataTypeTable()
{
    Tcl_MutexLock(&tableMutex);
    if (auxDataTypeTableInitialized) {
        Tcl_DeleteHashTable(&auxDataTypeTable);
        auxDataTypeTableInitialized = 0;
    }
    Tcl_MutexUnlock(&tableMutex);
}

/*
 *----------------------------------------------------------------------
 *
 * GetCmdLocEncodingSize --
 *
 *      Computes the total number of bytes needed to encode the command
 *      location information for some compiled code.
 *
 * Results:
 *      The byte count needed to encode the compiled location information.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

static int
GetCmdLocEncodingSize(envPtr)
     CompileEnv *envPtr;        /* Points to compilation environment
                                 * structure containing the CmdLocation
                                 * structure to encode. */
{
    register CmdLocation *mapPtr = envPtr->cmdMapPtr;
    int numCmds = envPtr->numCommands;
    int codeDelta, codeLen, srcDelta, srcLen;
    int codeDeltaNext, codeLengthNext, srcDeltaNext, srcLengthNext;
                                /* The offsets in their respective byte
                                 * sequences where the next encoded offset
                                 * or length should go. */
    int prevCodeOffset, prevSrcOffset, i;

    codeDeltaNext = codeLengthNext = srcDeltaNext = srcLengthNext = 0;
    prevCodeOffset = prevSrcOffset = 0;
    for (i = 0;  i < numCmds;  i++) {
        codeDelta = (mapPtr[i].codeOffset - prevCodeOffset);
        if (codeDelta < 0) {
            panic("GetCmdLocEncodingSize: bad code offset");
        } else if (codeDelta <= 127) {
            codeDeltaNext++;
        } else {
            codeDeltaNext += 5;  /* 1 byte for 0xFF, 4 for positive delta */
        }
        prevCodeOffset = mapPtr[i].codeOffset;

        codeLen = mapPtr[i].numCodeBytes;
        if (codeLen < 0) {
            panic("GetCmdLocEncodingSize: bad code length");
        } else if (codeLen <= 127) {
            codeLengthNext++;
        } else {
            codeLengthNext += 5; /* 1 byte for 0xFF, 4 for length */
        }

        srcDelta = (mapPtr[i].srcOffset - prevSrcOffset);
        if ((-127 <= srcDelta) && (srcDelta <= 127)) {
            srcDeltaNext++;
        } else {
            srcDeltaNext += 5;   /* 1 byte for 0xFF, 4 for delta */
        }
        prevSrcOffset = mapPtr[i].srcOffset;

        srcLen = mapPtr[i].numSrcBytes;
        if (srcLen < 0) {
            panic("GetCmdLocEncodingSize: bad source length");
        } else if (srcLen <= 127) {
            srcLengthNext++;
        } else {
            srcLengthNext += 5;  /* 1 byte for 0xFF, 4 for length */
        }
    }

    return (codeDeltaNext + codeLengthNext + srcDeltaNext + srcLengthNext);
}

/*
 *----------------------------------------------------------------------
 *
 * EncodeCmdLocMap --
 *
 *      Encode the command location information for some compiled code into
 *      a ByteCode structure. The encoded command location map is stored as
 *      three adjacent byte sequences.
 *
 * Results:
 *      Pointer to the first byte after the encoded command location
 *      information.
 *
 * Side effects:
 *      The encoded information is stored into the block of memory headed
 *      by codePtr. Also records pointers to the start of the four byte
 *      sequences in fields in codePtr's ByteCode header structure.
 *
 *----------------------------------------------------------------------
 */

static unsigned char *
EncodeCmdLocMap(envPtr, codePtr, startPtr)
     CompileEnv *envPtr;        /* Points to compilation environment
                                 * structure containing the CmdLocation
                                 * structure to encode. */
     ByteCode *codePtr;         /* ByteCode in which to encode envPtr's
                                 * command location information. */
     unsigned char *startPtr;   /* Points to the first byte in codePtr's
                                 * memory block where the location
                                 * information is to be stored. */
{
    register CmdLocation *mapPtr = envPtr->cmdMapPtr;
    int numCmds = envPtr->numCommands;
    register unsigned char *p = startPtr;
    int codeDelta, codeLen, srcDelta, srcLen, prevOffset;
    register int i;
    
    /*
     * Encode the code offset for each command as a sequence of deltas.
     */

    codePtr->codeDeltaStart = p;
    prevOffset = 0;
    for (i = 0;  i < numCmds;  i++) {
        codeDelta = (mapPtr[i].codeOffset - prevOffset);
        if (codeDelta < 0) {
            panic("EncodeCmdLocMap: bad code offset");
        } else if (codeDelta <= 127) {
            TclStoreInt1AtPtr(codeDelta, p);
            p++;
        } else {
            TclStoreInt1AtPtr(0xFF, p);
            p++;
            TclStoreInt4AtPtr(codeDelta, p);
            p += 4;
        }
        prevOffset = mapPtr[i].codeOffset;
    }

    /*
     * Encode the code length for each command.
     */

    codePtr->codeLengthStart = p;
    for (i = 0;  i < numCmds;  i++) {
        codeLen = mapPtr[i].numCodeBytes;
        if (codeLen < 0) {
            panic("EncodeCmdLocMap: bad code length");
        } else if (codeLen <= 127) {
            TclStoreInt1AtPtr(codeLen, p);
            p++;
        } else {
            TclStoreInt1AtPtr(0xFF, p);
            p++;
            TclStoreInt4AtPtr(codeLen, p);
            p += 4;
        }
    }

    /*
     * Encode the source offset for each command as a sequence of deltas.
     */

    codePtr->srcDeltaStart = p;
    prevOffset = 0;
    for (i = 0;  i < numCmds;  i++) {
        srcDelta = (mapPtr[i].srcOffset - prevOffset);
        if ((-127 <= srcDelta) && (srcDelta <= 127)) {
            TclStoreInt1AtPtr(srcDelta, p);
            p++;
        } else {
            TclStoreInt1AtPtr(0xFF, p);
            p++;
            TclStoreInt4AtPtr(srcDelta, p);
            p += 4;
        }
        prevOffset = mapPtr[i].srcOffset;
    }

    /*
     * Encode the source length for each command.
     */

    codePtr->srcLengthStart = p;
    for (i = 0;  i < numCmds;  i++) {
        srcLen = mapPtr[i].numSrcBytes;
        if (srcLen < 0) {
            panic("EncodeCmdLocMap: bad source length");
        } else if (srcLen <= 127) {
            TclStoreInt1AtPtr(srcLen, p);
            p++;
        } else {
            TclStoreInt1AtPtr(0xFF, p);
            p++;
            TclStoreInt4AtPtr(srcLen, p);
            p += 4;
        }
    }
    
    return p;
}

#ifdef TCL_COMPILE_DEBUG
/*
 *----------------------------------------------------------------------
 *
 * TclPrintByteCodeObj --
 *
 *      This procedure prints ("disassembles") the instructions of a
 *      bytecode object to stdout.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

void
TclPrintByteCodeObj(interp, objPtr)
    Tcl_Interp *interp;         /* Used only for Tcl_GetStringFromObj. */
    Tcl_Obj *objPtr;            /* The bytecode object to disassemble. */
{
    ByteCode* codePtr = (ByteCode *) objPtr->internalRep.otherValuePtr;
    unsigned char *codeStart, *codeLimit, *pc;
    unsigned char *codeDeltaNext, *codeLengthNext;
    unsigned char *srcDeltaNext, *srcLengthNext;
    int codeOffset, codeLen, srcOffset, srcLen, numCmds, delta, i;
    Interp *iPtr = (Interp *) *codePtr->interpHandle;

    if (codePtr->refCount <= 0) {
        return;                 /* already freed */
    }

    codeStart = codePtr->codeStart;
    codeLimit = (codeStart + codePtr->numCodeBytes);
    numCmds = codePtr->numCommands;

    /*
     * Print header lines describing the ByteCode.
     */

    fprintf(stdout, "\nByteCode 0x%x, refCt %u, epoch %u, interp 0x%x (epoch %u)\n",
            (unsigned int) codePtr, codePtr->refCount,
            codePtr->compileEpoch, (unsigned int) iPtr,
            iPtr->compileEpoch);
    fprintf(stdout, "  Source ");
    TclPrintSource(stdout, codePtr->source,
            TclMin(codePtr->numSrcBytes, 55));
    fprintf(stdout, "\n  Cmds %d, src %d, inst %d, litObjs %u, aux %d, stkDepth %u, code/src %.2f\n",
            numCmds, codePtr->numSrcBytes, codePtr->numCodeBytes,
            codePtr->numLitObjects, codePtr->numAuxDataItems,
            codePtr->maxStackDepth,
#ifdef TCL_COMPILE_STATS
            (codePtr->numSrcBytes?
                    ((float)codePtr->structureSize)/((float)codePtr->numSrcBytes) : 0.0));
#else
            0.0);
#endif
#ifdef TCL_COMPILE_STATS
    fprintf(stdout,
            "  Code %d = header %d+inst %d+litObj %d+exc %d+aux %d+cmdMap %d\n",
            codePtr->structureSize,
            (sizeof(ByteCode) - (sizeof(size_t) + sizeof(Tcl_Time))),
            codePtr->numCodeBytes,
            (codePtr->numLitObjects * sizeof(Tcl_Obj *)),
            (codePtr->numExceptRanges * sizeof(ExceptionRange)),
            (codePtr->numAuxDataItems * sizeof(AuxData)),
            codePtr->numCmdLocBytes);
#endif /* TCL_COMPILE_STATS */
    
    /*
     * If the ByteCode is the compiled body of a Tcl procedure, print
     * information about that procedure. Note that we don't know the
     * procedure's name since ByteCode's can be shared among procedures.
     */
    
    if (codePtr->procPtr != NULL) {
        Proc *procPtr = codePtr->procPtr;
        int numCompiledLocals = procPtr->numCompiledLocals;
        fprintf(stdout,
                "  Proc 0x%x, refCt %d, args %d, compiled locals %d\n",
                (unsigned int) procPtr, procPtr->refCount, procPtr->numArgs,
                numCompiledLocals);
        if (numCompiledLocals > 0) {
            CompiledLocal *localPtr = procPtr->firstLocalPtr;
            for (i = 0;  i < numCompiledLocals;  i++) {
                fprintf(stdout, "      slot %d%s%s%s%s%s%s", i, 
                        ((localPtr->flags & VAR_SCALAR)?  ", scalar"  : ""),
                        ((localPtr->flags & VAR_ARRAY)?  ", array"  : ""),
                        ((localPtr->flags & VAR_LINK)?  ", link"  : ""),
                        ((localPtr->flags & VAR_ARGUMENT)?  ", arg"  : ""),
                        ((localPtr->flags & VAR_TEMPORARY)? ", temp" : ""),
                        ((localPtr->flags & VAR_RESOLVED)? ", resolved" : ""));
                if (TclIsVarTemporary(localPtr)) {
                    fprintf(stdout,     "\n");
                } else {
                    fprintf(stdout,     ", \"%s\"\n", localPtr->name);
                }
                localPtr = localPtr->nextPtr;
            }
        }
    }

    /*
     * Print the ExceptionRange array.
     */

    if (codePtr->numExceptRanges > 0) {
        fprintf(stdout, "  Exception ranges %d, depth %d:\n",
                codePtr->numExceptRanges, codePtr->maxExceptDepth);
        for (i = 0;  i < codePtr->numExceptRanges;  i++) {
            ExceptionRange *rangePtr = &(codePtr->exceptArrayPtr[i]);
            fprintf(stdout, "      %d: level %d, %s, pc %d-%d, ",
                    i, rangePtr->nestingLevel,
                    ((rangePtr->type == LOOP_EXCEPTION_RANGE)
                            ? "loop" : "catch"),
                    rangePtr->codeOffset,
                    (rangePtr->codeOffset + rangePtr->numCodeBytes - 1));
            switch (rangePtr->type) {
            case LOOP_EXCEPTION_RANGE:
                fprintf(stdout, "continue %d, break %d\n",
                        rangePtr->continueOffset, rangePtr->breakOffset);
                break;
            case CATCH_EXCEPTION_RANGE:
                fprintf(stdout, "catch %d\n", rangePtr->catchOffset);
                break;
            default:
                panic("TclPrintByteCodeObj: bad ExceptionRange type %d\n",
                        rangePtr->type);
            }
        }
    }
    
    /*
     * If there were no commands (e.g., an expression or an empty string
     * was compiled), just print all instructions and return.
     */

    if (numCmds == 0) {
        pc = codeStart;
        while (pc < codeLimit) {
            fprintf(stdout, "    ");
            pc += TclPrintInstruction(codePtr, pc);
        }
        return;
    }
    
    /*
     * Print table showing the code offset, source offset, and source
     * length for each command. These are encoded as a sequence of bytes.
     */

    fprintf(stdout, "  Commands %d:", numCmds);
    codeDeltaNext = codePtr->codeDeltaStart;
    codeLengthNext = codePtr->codeLengthStart;
    srcDeltaNext  = codePtr->srcDeltaStart;
    srcLengthNext = codePtr->srcLengthStart;
    codeOffset = srcOffset = 0;
    for (i = 0;  i < numCmds;  i++) {
        if ((unsigned int) (*codeDeltaNext) == (unsigned int) 0xFF) {
            codeDeltaNext++;
            delta = TclGetInt4AtPtr(codeDeltaNext);
            codeDeltaNext += 4;
        } else {
            delta = TclGetInt1AtPtr(codeDeltaNext);
            codeDeltaNext++;
        }
        codeOffset += delta;

        if ((unsigned int) (*codeLengthNext) == (unsigned int) 0xFF) {
            codeLengthNext++;
            codeLen = TclGetInt4AtPtr(codeLengthNext);
            codeLengthNext += 4;
        } else {
            codeLen = TclGetInt1AtPtr(codeLengthNext);
            codeLengthNext++;
        }
        
        if ((unsigned int) (*srcDeltaNext) == (unsigned int) 0xFF) {
            srcDeltaNext++;
            delta = TclGetInt4AtPtr(srcDeltaNext);
            srcDeltaNext += 4;
        } else {
            delta = TclGetInt1AtPtr(srcDeltaNext);
            srcDeltaNext++;
        }
        srcOffset += delta;

        if ((unsigned int) (*srcLengthNext) == (unsigned int) 0xFF) {
            srcLengthNext++;
            srcLen = TclGetInt4AtPtr(srcLengthNext);
            srcLengthNext += 4;
        } else {
            srcLen = TclGetInt1AtPtr(srcLengthNext);
            srcLengthNext++;
        }
        
        fprintf(stdout, "%s%4d: pc %d-%d, src %d-%d",
                ((i % 2)? "     " : "\n   "),
                (i+1), codeOffset, (codeOffset + codeLen - 1),
                srcOffset, (srcOffset + srcLen - 1));
    }
    if (numCmds > 0) {
        fprintf(stdout, "\n");
    }
    
    /*
     * Print each instruction. If the instruction corresponds to the start
     * of a command, print the command's source. Note that we don't need
     * the code length here.
     */

    codeDeltaNext = codePtr->codeDeltaStart;
    srcDeltaNext  = codePtr->srcDeltaStart;
    srcLengthNext = codePtr->srcLengthStart;
    codeOffset = srcOffset = 0;
    pc = codeStart;
    for (i = 0;  i < numCmds;  i++) {
        if ((unsigned int) (*codeDeltaNext) == (unsigned int) 0xFF) {
            codeDeltaNext++;
            delta = TclGetInt4AtPtr(codeDeltaNext);
            codeDeltaNext += 4;
        } else {
            delta = TclGetInt1AtPtr(codeDeltaNext);
            codeDeltaNext++;
        }
        codeOffset += delta;

        if ((unsigned int) (*srcDeltaNext) == (unsigned int) 0xFF) {
            srcDeltaNext++;
            delta = TclGetInt4AtPtr(srcDeltaNext);
            srcDeltaNext += 4;
        } else {
            delta = TclGetInt1AtPtr(srcDeltaNext);
            srcDeltaNext++;
        }
        srcOffset += delta;

        if ((unsigned int) (*srcLengthNext) == (unsigned int) 0xFF) {
            srcLengthNext++;
            srcLen = TclGetInt4AtPtr(srcLengthNext);
            srcLengthNext += 4;
        } else {
            srcLen = TclGetInt1AtPtr(srcLengthNext);
            srcLengthNext++;
        }

        /*
         * Print instructions before command i.
         */
        
        while ((pc-codeStart) < codeOffset) {
            fprintf(stdout, "    ");
            pc += TclPrintInstruction(codePtr, pc);
        }

        fprintf(stdout, "  Command %d: ", (i+1));
        TclPrintSource(stdout, (codePtr->source + srcOffset),
                TclMin(srcLen, 55));
        fprintf(stdout, "\n");
    }
    if (pc < codeLimit) {
        /*
         * Print instructions after the last command.
         */

        while (pc < codeLimit) {
            fprintf(stdout, "    ");
            pc += TclPrintInstruction(codePtr, pc);
        }
    }
}
#endif /* TCL_COMPILE_DEBUG */

/*
 *----------------------------------------------------------------------
 *
 * TclPrintInstruction --
 *
 *      This procedure prints ("disassembles") one instruction from a
 *      bytecode object to stdout.
 *
 * Results:
 *      Returns the length in bytes of the current instruiction.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

int
TclPrintInstruction(codePtr, pc)
    ByteCode* codePtr;          /* Bytecode containing the instruction. */
    unsigned char *pc;          /* Points to first byte of instruction. */
{
    Proc *procPtr = codePtr->procPtr;
    unsigned char opCode = *pc;
    register InstructionDesc *instDesc = &instructionTable[opCode];
    unsigned char *codeStart = codePtr->codeStart;
    unsigned int pcOffset = (pc - codeStart);
    int opnd, i, j;
    
    fprintf(stdout, "(%u) %s ", pcOffset, instDesc->name);
    for (i = 0;  i < instDesc->numOperands;  i++) {
        switch (instDesc->opTypes[i]) {
        case OPERAND_INT1:
            opnd = TclGetInt1AtPtr(pc+1+i);
            if ((i == 0) && ((opCode == INST_JUMP1)
                             || (opCode == INST_JUMP_TRUE1)
                             || (opCode == INST_JUMP_FALSE1))) {
                fprintf(stdout, "%d     # pc %u", opnd, (pcOffset + opnd));
            } else {
                fprintf(stdout, "%d", opnd);
            }
            break;
        case OPERAND_INT4:
            opnd = TclGetInt4AtPtr(pc+1+i);
            if ((i == 0) && ((opCode == INST_JUMP4)
                             || (opCode == INST_JUMP_TRUE4)
                             || (opCode == INST_JUMP_FALSE4))) {
                fprintf(stdout, "%d     # pc %u", opnd, (pcOffset + opnd));
            } else {
                fprintf(stdout, "%d", opnd);
            }
            break;
        case OPERAND_UINT1:
            opnd = TclGetUInt1AtPtr(pc+1+i);
            if ((i == 0) && (opCode == INST_PUSH1)) {
                fprintf(stdout, "%u     # ", (unsigned int) opnd);
                TclPrintObject(stdout, codePtr->objArrayPtr[opnd], 40);
            } else if ((i == 0) && ((opCode == INST_LOAD_SCALAR1)
                                    || (opCode == INST_LOAD_ARRAY1)
                                    || (opCode == INST_STORE_SCALAR1)
                                    || (opCode == INST_STORE_ARRAY1))) {
                int localCt = procPtr->numCompiledLocals;
                CompiledLocal *localPtr = procPtr->firstLocalPtr;
                if (opnd >= localCt) {
                    panic("TclPrintInstruction: bad local var index %u (%u locals)\n",
                             (unsigned int) opnd, localCt);
                    return instDesc->numBytes;
                }
                for (j = 0;  j < opnd;  j++) {
                    localPtr = localPtr->nextPtr;
                }
                if (TclIsVarTemporary(localPtr)) {
                    fprintf(stdout, "%u # temp var %u",
                            (unsigned int) opnd, (unsigned int) opnd);
                } else {
                    fprintf(stdout, "%u # var ", (unsigned int) opnd);
                    TclPrintSource(stdout, localPtr->name, 40);
                }
            } else {
                fprintf(stdout, "%u ", (unsigned int) opnd);
            }
            break;
        case OPERAND_UINT4:
            opnd = TclGetUInt4AtPtr(pc+1+i);
            if (opCode == INST_PUSH4) {
                fprintf(stdout, "%u     # ", opnd);
                TclPrintObject(stdout, codePtr->objArrayPtr[opnd], 40);
            } else if ((i == 0) && ((opCode == INST_LOAD_SCALAR4)
                                    || (opCode == INST_LOAD_ARRAY4)
                                    || (opCode == INST_STORE_SCALAR4)
                                    || (opCode == INST_STORE_ARRAY4))) {
                int localCt = procPtr->numCompiledLocals;
                CompiledLocal *localPtr = procPtr->firstLocalPtr;
                if (opnd >= localCt) {
                    panic("TclPrintInstruction: bad local var index %u (%u locals)\n",
                             (unsigned int) opnd, localCt);
                    return instDesc->numBytes;
                }
                for (j = 0;  j < opnd;  j++) {
                    localPtr = localPtr->nextPtr;
                }
                if (TclIsVarTemporary(localPtr)) {
                    fprintf(stdout, "%u # temp var %u",
                            (unsigned int) opnd, (unsigned int) opnd);
                } else {
                    fprintf(stdout, "%u # var ", (unsigned int) opnd);
                    TclPrintSource(stdout, localPtr->name, 40);
                }
            } else {
                fprintf(stdout, "%u ", (unsigned int) opnd);
            }
            break;
        case OPERAND_NONE:
        default:
            break;
        }
    }
    fprintf(stdout, "\n");
    return instDesc->numBytes;
}

/*
 *----------------------------------------------------------------------
 *
 * TclPrintObject --
 *
 *      This procedure prints up to a specified number of characters from
 *      the argument Tcl object's string representation to a specified file.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Outputs characters to the specified file.
 *
 *----------------------------------------------------------------------
 */

void
TclPrintObject(outFile, objPtr, maxChars)
    FILE *outFile;              /* The file to print the source to. */
    Tcl_Obj *objPtr;            /* Points to the Tcl object whose string
                                 * representation should be printed. */
    int maxChars;               /* Maximum number of chars to print. */
{
    char *bytes;
    int length;
    
    bytes = Tcl_GetStringFromObj(objPtr, &length);
    TclPrintSource(outFile, bytes, TclMin(length, maxChars));
}

/*
 *----------------------------------------------------------------------
 *
 * TclPrintSource --
 *
 *      This procedure prints up to a specified number of characters from
 *      the argument string to a specified file. It tries to produce legible
 *      output by adding backslashes as necessary.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Outputs characters to the specified file.
 *
 *----------------------------------------------------------------------
 */

void
TclPrintSource(outFile, string, maxChars)
    FILE *outFile;              /* The file to print the source to. */
    char *string;               /* The string to print. */
    int maxChars;               /* Maximum number of chars to print. */
{
    register char *p;
    register int i = 0;

    if (string == NULL) {
        fprintf(outFile, "\"\"");
        return;
    }

    fprintf(outFile, "\"");
    p = string;
    for (;  (*p != '\0') && (i < maxChars);  p++, i++) {
        switch (*p) {
            case '"':
                fprintf(outFile, "\\\"");
                continue;
            case '\f':
                fprintf(outFile, "\\f");
                continue;
            case '\n':
                fprintf(outFile, "\\n");
                continue;
            case '\r':
                fprintf(outFile, "\\r");
                continue;
            case '\t':
                fprintf(outFile, "\\t");
                continue;
            case '\v':
                fprintf(outFile, "\\v");
                continue;
            default:
                fprintf(outFile, "%c", *p);
                continue;
        }
    }
    fprintf(outFile, "\"");
}

#ifdef TCL_COMPILE_STATS
/*
 *----------------------------------------------------------------------
 *
 * RecordByteCodeStats --
 *
 *      Accumulates various compilation-related statistics for each newly
 *      compiled ByteCode. Called by the TclInitByteCodeObj when Tcl is
 *      compiled with the -DTCL_COMPILE_STATS flag
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Accumulates aggregate code-related statistics in the interpreter's
 *      ByteCodeStats structure. Records statistics specific to a ByteCode
 *      in its ByteCode structure.
 *
 *----------------------------------------------------------------------
 */

void
RecordByteCodeStats(codePtr)
    ByteCode *codePtr;          /* Points to ByteCode structure with info
                                 * to add to accumulated statistics. */
{
    Interp *iPtr = (Interp *) *codePtr->interpHandle;
    register ByteCodeStats *statsPtr = &(iPtr->stats);

    statsPtr->numCompilations++;
    statsPtr->totalSrcBytes        += (double) codePtr->numSrcBytes;
    statsPtr->totalByteCodeBytes   += (double) codePtr->structureSize;
    statsPtr->currentSrcBytes      += (double) codePtr->numSrcBytes;
    statsPtr->currentByteCodeBytes += (double) codePtr->structureSize;
    
    statsPtr->srcCount[TclLog2(codePtr->numSrcBytes)]++;
    statsPtr->byteCodeCount[TclLog2(codePtr->structureSize)]++;

    statsPtr->currentInstBytes   += (double) codePtr->numCodeBytes;
    statsPtr->currentLitBytes    +=
            (double) (codePtr->numLitObjects * sizeof(Tcl_Obj *)); 
    statsPtr->currentExceptBytes +=
            (double) (codePtr->numExceptRanges * sizeof(ExceptionRange));
    statsPtr->currentAuxBytes    +=
            (double) (codePtr->numAuxDataItems * sizeof(AuxData));
    statsPtr->currentCmdMapBytes += (double) codePtr->numCmdLocBytes;
}
#endif /* TCL_COMPILE_STATS */

/* End of tclcompile.c */