if (getenv("TCL_PKG_PREFER_LATEST") == NULL) {
	iPtr->packagePrefer = PKG_PREFER_STABLE;
    } else
#endif
	iPtr->packagePrefer = PKG_PREFER_LATEST;

    iPtr->cmdCount = 0;
    TclInitLiteralTable(&iPtr->literalTable);
    iPtr->compileEpoch = 1;
    iPtr->compiledProcPtr = NULL;
    iPtr->resolverPtr = NULL;
    iPtr->evalFlags = 0;
    iPtr->scriptFile = NULL;
    iPtr->flags = 0;
    iPtr->tracePtr = NULL;

    while (resPtr) {
	nextResPtr = resPtr->nextPtr;
	Tcl_Free(resPtr->name);
	Tcl_Free(resPtr);
	resPtr = nextResPtr;
    }

    /*
     * Free up literal objects created for scripts compiled by the
     * interpreter.
     */

    TclDeleteLiteralTable(interp, &iPtr->literalTable);

    /*
     * TIP #280 - Release the arrays for ByteCode/Proc extension, and
     * contents.
     */

    for (hPtr = Tcl_FirstHashEntry(iPtr->linePBodyPtr, &search);
	    hPtr != NULL;

EvalStatsCmd(
    ClientData unused,		/* Unused. */
    Tcl_Interp *interp,		/* The current interpreter. */
    int objc,			/* The number of arguments. */
    Tcl_Obj *const objv[])	/* The argument strings. */
{
    Interp *iPtr = (Interp *) interp;

    LiteralTable *globalTablePtr = &iPtr->literalTable;

    ByteCodeStats *statsPtr = &iPtr->stats;
    double totalCodeBytes, currentCodeBytes;
    double totalLiteralBytes, currentLiteralBytes;
    double objBytesIfUnshared, strBytesIfUnshared, sharingBytesSaved;
    double strBytesSharedMultX, strBytesSharedOnce;
    double numInstructions, currentHeaderBytes;
    size_t numCurrentByteCodes, numByteCodeLits;

    for (i = 0;  i < 256;  i++) {
	if (statsPtr->instructionCount[i] != 0) {
	    numInstructions += statsPtr->instructionCount[i];
	}
    }

    totalLiteralBytes = sizeof(LiteralTable)

	    + iPtr->literalTable.numBuckets * sizeof(LiteralEntry *)

	    + (statsPtr->numLiteralsCreated * sizeof(LiteralEntry))
	    + (statsPtr->numLiteralsCreated * sizeof(Tcl_Obj))
	    + statsPtr->totalLitStringBytes;
    totalCodeBytes = statsPtr->totalByteCodeBytes + totalLiteralBytes;

    numCurrentByteCodes =
	    statsPtr->numCompilations - statsPtr->numByteCodesFreed;
    currentHeaderBytes = numCurrentByteCodes
	    * (sizeof(ByteCode) - sizeof(size_t) - sizeof(Tcl_Time));
    literalMgmtBytes = sizeof(LiteralTable)

	    + (iPtr->literalTable.numBuckets * sizeof(LiteralEntry *))
	    + (iPtr->literalTable.numEntries * sizeof(LiteralEntry));


    currentLiteralBytes = literalMgmtBytes

	    + iPtr->literalTable.numEntries * sizeof(Tcl_Obj)

	    + statsPtr->currentLitStringBytes;
    currentCodeBytes = statsPtr->currentByteCodeBytes + currentLiteralBytes;

    /*
     * Summary statistics, total and current source and ByteCode sizes.
     */

	    totalCodeBytes);
    Tcl_AppendPrintfToObj(objPtr, "    ByteCode bytes\t\t%.6g\n",
	    statsPtr->totalByteCodeBytes);
    Tcl_AppendPrintfToObj(objPtr, "    Literal bytes\t\t%.6g\n",
	    totalLiteralBytes);
    Tcl_AppendPrintfToObj(objPtr, "      table %" TCL_Z_MODIFIER "u + bkts %" TCL_Z_MODIFIER "u + entries %" TCL_Z_MODIFIER "u + objects %" TCL_Z_MODIFIER "u + strings %.6g\n",
	    sizeof(LiteralTable),

	    iPtr->literalTable.numBuckets * sizeof(LiteralEntry *),



	    statsPtr->numLiteralsCreated * sizeof(LiteralEntry),
	    statsPtr->numLiteralsCreated * sizeof(Tcl_Obj),
	    statsPtr->totalLitStringBytes);
    Tcl_AppendPrintfToObj(objPtr, "  Mean code/compile\t\t%.1f\n",
	    totalCodeBytes / statsPtr->numCompilations);
    Tcl_AppendPrintfToObj(objPtr, "  Mean code/source\t\t%.1f\n",
	    totalCodeBytes / statsPtr->totalSrcBytes);

    Tcl_AppendPrintfToObj(objPtr, "\nCurrent (active) ByteCodes\t%" TCL_Z_MODIFIER "u\n",
	    numCurrentByteCodes);
    Tcl_AppendPrintfToObj(objPtr, "  Source bytes\t\t\t%.6g\n",
	    statsPtr->currentSrcBytes);
    Tcl_AppendPrintfToObj(objPtr, "  Code bytes\t\t\t%.6g\n",
	    currentCodeBytes);
    Tcl_AppendPrintfToObj(objPtr, "    ByteCode bytes\t\t%.6g\n",
	    statsPtr->currentByteCodeBytes);
    Tcl_AppendPrintfToObj(objPtr, "    Literal bytes\t\t%.6g\n",
	    currentLiteralBytes);
    Tcl_AppendPrintfToObj(objPtr, "      table %" TCL_Z_MODIFIER "u + bkts %" TCL_Z_MODIFIER "u + entries %" TCL_Z_MODIFIER "u + objects %" TCL_Z_MODIFIER "u + strings %.6g\n",
	    sizeof(LiteralTable),

	    iPtr->literalTable.numBuckets * sizeof(LiteralEntry *),
	    iPtr->literalTable.numEntries * sizeof(LiteralEntry),
	    iPtr->literalTable.numEntries * sizeof(Tcl_Obj),



	    statsPtr->currentLitStringBytes);
    Tcl_AppendPrintfToObj(objPtr, "  Mean code/source\t\t%.1f\n",
	    currentCodeBytes / statsPtr->currentSrcBytes);
    Tcl_AppendPrintfToObj(objPtr, "  Code + source bytes\t\t%.6g (%0.1f mean code/src)\n",
	    (currentCodeBytes + statsPtr->currentSrcBytes),
	    (currentCodeBytes / statsPtr->currentSrcBytes) + 1.0);

    refCountSum = 0;
    numSharedMultX = 0;
    numSharedOnce = 0;
    objBytesIfUnshared = 0.0;
    strBytesIfUnshared = 0.0;
    strBytesSharedMultX = 0.0;
    strBytesSharedOnce = 0.0;

    for (i = 0;  i < globalTablePtr->numBuckets;  i++) {
	for (entryPtr = globalTablePtr->buckets[i];  entryPtr != NULL;
		entryPtr = entryPtr->nextPtr) {
	    if (TclHasIntRep(entryPtr->objPtr, &tclByteCodeType)) {
		numByteCodeLits++;
	    }
	    (void) TclGetStringFromObj(entryPtr->objPtr, &length);
	    refCountSum += entryPtr->refCount;
	    objBytesIfUnshared += (entryPtr->refCount * sizeof(Tcl_Obj));
	    strBytesIfUnshared += (entryPtr->refCount * (length+1));
	    if (entryPtr->refCount > 1) {
		numSharedMultX++;
		strBytesSharedMultX += (length+1);
	    } else {
		numSharedOnce++;
		strBytesSharedOnce += (length+1);
	    }
	}
    }

    sharingBytesSaved = (objBytesIfUnshared + strBytesIfUnshared)
	    - currentLiteralBytes;

    Tcl_AppendPrintfToObj(objPtr, "\nTotal objects (all interps)\t%" TCL_Z_MODIFIER "u\n",
	    tclObjsAlloced);
    Tcl_AppendPrintfToObj(objPtr, "Current objects\t\t\t%" TCL_Z_MODIFIER "u\n",
	    (tclObjsAlloced - tclObjsFreed));
    Tcl_AppendPrintfToObj(objPtr, "Total literal objects\t\t%" TCL_Z_MODIFIER "u\n",
	    statsPtr->numLiteralsCreated);

    Tcl_AppendPrintfToObj(objPtr, "\nCurrent literal objects\t\t%" TCL_Z_MODIFIER "u (%0.1f%% of current objects)\n",

	    globalTablePtr->numEntries,
	    Percent(globalTablePtr->numEntries, tclObjsAlloced-tclObjsFreed));



    Tcl_AppendPrintfToObj(objPtr, "  ByteCode literals\t\t%" TCL_Z_MODIFIER "u (%0.1f%% of current literals)\n",
	    numByteCodeLits,
	    Percent(numByteCodeLits, globalTablePtr->numEntries));
    Tcl_AppendPrintfToObj(objPtr, "  Literals reused > 1x\t\t%" TCL_Z_MODIFIER "u\n",
	    numSharedMultX);
    Tcl_AppendPrintfToObj(objPtr, "  Mean reference count\t\t%.2f\n",
	    ((double) refCountSum) / globalTablePtr->numEntries);
    Tcl_AppendPrintfToObj(objPtr, "  Mean len, str reused >1x \t%.2f\n",
	    (numSharedMultX ? strBytesSharedMultX/numSharedMultX : 0.0));
    Tcl_AppendPrintfToObj(objPtr, "  Mean len, str used 1x\t\t%.2f\n",
	    (numSharedOnce ? strBytesSharedOnce/numSharedOnce : 0.0));
    Tcl_AppendPrintfToObj(objPtr, "  Total sharing savings\t\t%.6g (%0.1f%% of bytes if no sharing)\n",
	    sharingBytesSaved,
	    Percent(sharingBytesSaved, objBytesIfUnshared+strBytesIfUnshared));
    Tcl_AppendPrintfToObj(objPtr, "    Bytes with sharing\t\t%.6g\n",
	    currentLiteralBytes);
    Tcl_AppendPrintfToObj(objPtr, "      table %lu + bkts %lu + entries %lu + objects %lu + strings %.6g\n",
	    (unsigned long) sizeof(LiteralTable),

	    (unsigned long) (iPtr->literalTable.numBuckets * sizeof(LiteralEntry *)),
	    (unsigned long) (iPtr->literalTable.numEntries * sizeof(LiteralEntry)),
	    (unsigned long) (iPtr->literalTable.numEntries * sizeof(Tcl_Obj)),



	    statsPtr->currentLitStringBytes);
    Tcl_AppendPrintfToObj(objPtr, "    Bytes if no sharing\t\t%.6g = objects %.6g + strings %.6g\n",
	    (objBytesIfUnshared + strBytesIfUnshared),
	    objBytesIfUnshared, strBytesIfUnshared);
    Tcl_AppendPrintfToObj(objPtr, "  String sharing savings \t%.6g = unshared %.6g - shared %.6g\n",
	    (strBytesIfUnshared - statsPtr->currentLitStringBytes),
	    strBytesIfUnshared, statsPtr->currentLitStringBytes);
    Tcl_AppendPrintfToObj(objPtr, "  Literal mgmt overhead\t\t%" TCL_Z_MODIFIER "u (%0.1f%% of bytes with sharing)\n",
	    literalMgmtBytes,
	    Percent(literalMgmtBytes, currentLiteralBytes));
    Tcl_AppendPrintfToObj(objPtr, "    table %lu + buckets %lu + entries %lu\n",
	    (unsigned long) sizeof(LiteralTable),

	    (unsigned long) (iPtr->literalTable.numBuckets * sizeof(LiteralEntry *)),
	    (unsigned long) (iPtr->literalTable.numEntries * sizeof(LiteralEntry)));





    /*
     * Breakdown of current ByteCode space requirements.
     */

    Tcl_AppendPrintfToObj(objPtr, "\nBreakdown of current ByteCode requirements:\n");
    Tcl_AppendPrintfToObj(objPtr, "                         Bytes      Pct of    Avg per\n");

    for (i = 0;  i <= maxSizeDecade;  i++) {
	decadeHigh = (1 << (i+1)) - 1;
	sum += statsPtr->literalCount[i];
	Tcl_AppendPrintfToObj(objPtr, "\t%10" TCL_Z_MODIFIER "u\t\t%8.0f%%\n",
		decadeHigh, Percent(sum, statsPtr->numLiteralsCreated));
    }


    litTableStats = TclLiteralStats(globalTablePtr);
    Tcl_AppendPrintfToObj(objPtr, "\nCurrent literal table statistics:\n%s\n",
	    litTableStats);
    Tcl_Free(litTableStats);


    /*
     * Source and ByteCode size distributions.
     */

    Tcl_AppendPrintfToObj(objPtr, "\nSource sizes:\n");
    Tcl_AppendPrintfToObj(objPtr, "\t Up to size\t\tPercentage\n");

    size_t cmdCount;		/* Total number of times a command procedure
				 * has been called for this interpreter. */
    int evalFlags;		/* Flags to control next call to Tcl_Eval.
				 * Normally zero, but may be set before
				 * calling Tcl_Eval. See below for valid
				 * values. */
    LiteralTable literalTable;	/* Contains LiteralEntry's describing all Tcl
				 * objects holding literals of scripts
				 * compiled by the interpreter. Indexed by the
				 * string representations of literals. Used to
				 * avoid creating duplicate objects. */
    size_t compileEpoch;	/* Holds the current "compilation epoch" for
				 * this interpreter. This is incremented to
				 * invalidate existing ByteCodes when, e.g., a
				 * command with a compile procedure is
				 * redefined. */
    Proc *compiledProcPtr;	/* If a procedure is being compiled, a pointer
				 * to its Proc structure; otherwise, this is

    size_t hash,		/* The string's hash. If -1, it will be
				 * computed here. */
    int *newPtr,
    Namespace *nsPtr,
    int flags,
    LiteralEntry **globalPtrPtr)
{
    LiteralTable *globalTablePtr = &iPtr->literalTable;
    LiteralEntry *globalPtr;
    size_t globalHash;
    Tcl_Obj *objPtr;

    /*
     * Is it in the interpreter's global literal table?
     */

    if (hash == TCL_AUTO_LENGTH) {
	hash = HashString(bytes, length);
    }
    globalHash = (hash & globalTablePtr->mask);
    for (globalPtr=globalTablePtr->buckets[globalHash] ; globalPtr!=NULL;
	    globalPtr = globalPtr->nextPtr) {
	objPtr = globalPtr->objPtr;
	if (globalPtr->nsPtr == nsPtr) {
	    /*
	     * Literals should always have UTF-8 representations... but this
	     * is not guaranteed so we need to be careful anyway.
	     *
	     * https://stackoverflow.com/q/54337750/301832
	     */

	    size_t objLength;
	    char *objBytes = TclGetStringFromObj(objPtr, &objLength);

	    if ((objLength == length) && ((length == 0)
		    || ((objBytes[0] == bytes[0])
		    && (memcmp(objBytes, bytes, length) == 0)))) {
		/*
		 * A literal was found: return it
		 */

		if (newPtr) {
		    *newPtr = 0;
		}
		if (globalPtrPtr) {
		    *globalPtrPtr = globalPtr;
		}
		if (flags & LITERAL_ON_HEAP) {
		    Tcl_Free((void *)bytes);
		}
		if (globalPtr->refCount != TCL_AUTO_LENGTH) {
		    globalPtr->refCount++;
		}
		return objPtr;
	    }
	}
    }
    if (!newPtr) {
	if ((flags & LITERAL_ON_HEAP)) {
	    Tcl_Free((void *)bytes);
	}
	return NULL;
    }

    /*
     * The literal is new to the interpreter.
     */

    TclNewObj(objPtr);
    if ((flags & LITERAL_ON_HEAP)) {
	objPtr->bytes = (char *) bytes;
	objPtr->length = length;
    } else {
	TclInitStringRep(objPtr, bytes, length);
    }

    /* Should the new literal be shared globally? */

    if ((flags & LITERAL_UNSHARED)) {
	/*
	 * No, do *not* add it the global literal table
	 * Make clear, that no global value is returned
	 */
	if (globalPtrPtr != NULL) {
	    *globalPtrPtr = NULL;
	}
	return objPtr;
    }

    /*
     * Yes, add it to the global literal table.
     */
#ifdef TCL_COMPILE_DEBUG
    if (LookupLiteralEntry((Tcl_Interp *) iPtr, objPtr) != NULL) {
	Tcl_Panic("%s: literal \"%.*s\" found globally but shouldn't be",
		"TclRegisterLiteral", (length>60? 60 : (int)length), bytes);
    }
#endif

    globalPtr = Tcl_Alloc(sizeof(LiteralEntry));
    globalPtr->objPtr = objPtr;
    Tcl_IncrRefCount(objPtr);
    globalPtr->refCount = 1;
    globalPtr->nsPtr = nsPtr;
    globalPtr->nextPtr = globalTablePtr->buckets[globalHash];
    globalTablePtr->buckets[globalHash] = globalPtr;
    globalTablePtr->numEntries++;

    /*
     * If the global literal table has exceeded a decent size, rebuild it with
     * more buckets.
     */

    if (globalTablePtr->numEntries >= globalTablePtr->rebuildSize) {
	RebuildLiteralTable(globalTablePtr);
    }

#ifdef TCL_COMPILE_DEBUG
    TclVerifyGlobalLiteralTable(iPtr);
    {
	LiteralEntry *entryPtr;
	int found;
	size_t i;

	found = 0;
	for (i=0 ; i<globalTablePtr->numBuckets ; i++) {
	    for (entryPtr=globalTablePtr->buckets[i]; entryPtr!=NULL ;
		    entryPtr=entryPtr->nextPtr) {
		if ((entryPtr == globalPtr) && (entryPtr->objPtr == objPtr)) {
		    found = 1;
		}
	    }
	}
	if (!found) {
	    Tcl_Panic("%s: literal \"%.*s\" wasn't global",
		    "TclRegisterLiteral", (length>60? 60 : (int)length), bytes);
	}
    }
#endif /*TCL_COMPILE_DEBUG*/

#ifdef TCL_COMPILE_STATS
    iPtr->stats.numLiteralsCreated++;
    iPtr->stats.totalLitStringBytes += (double) (length + 1);
    iPtr->stats.currentLitStringBytes += (double) (length + 1);
    iPtr->stats.literalCount[TclLog2(length)]++;
#endif /*TCL_COMPILE_STATS*/

    if (globalPtrPtr) {
	*globalPtrPtr = globalPtr;
    }
    *newPtr = 1;
    return objPtr;
}

/*
 *----------------------------------------------------------------------
 *

				 * this function. If LITERAL_CMD_NAME then
				 * the literal should not be shared accross
				 * namespaces. */
{
    CompileEnv *envPtr = ePtr;
    Interp *iPtr = envPtr->iPtr;
    LiteralTable *localTablePtr = &envPtr->localLitTable;
    LiteralEntry *globalPtr, *localPtr;
    Tcl_Obj *objPtr;
    size_t hash, localHash, objIndex;
    int new;
    Namespace *nsPtr;

    if (length == TCL_AUTO_LENGTH) {
	length = (bytes ? strlen(bytes) : 0);

	nsPtr = NULL;
    }

    /*
     * Is it in the interpreter's global literal table? If not, create it.
     */

    globalPtr = NULL;
    objPtr = TclCreateLiteral(iPtr, bytes, length, hash, &new, nsPtr, flags,
	    &globalPtr);
    objIndex = AddLocalLiteralEntry(envPtr, objPtr, localHash);

#ifdef TCL_COMPILE_DEBUG
    if (globalPtr != NULL && (globalPtr->refCount + 1 < 2)) {
	Tcl_Panic("%s: global literal \"%.*s\" had bad refCount %" TCL_Z_MODIFIER "u",
		"TclRegisterLiteral", (length>60? 60 : (int)length), bytes,
		globalPtr->refCount);
    }
    TclVerifyLocalLiteralTable(envPtr);
#endif /*TCL_COMPILE_DEBUG*/
    return objIndex;
}

#ifdef TCL_COMPILE_DEBUG
/*

LookupLiteralEntry(
    Tcl_Interp *interp,		/* Interpreter for which objPtr was created to
				 * hold a literal. */
    register Tcl_Obj *objPtr)	/* Points to a Tcl object holding a literal
				 * that was previously created by a call to
				 * TclRegisterLiteral. */
{
    Interp *iPtr = (Interp *) interp;
    LiteralTable *globalTablePtr = &iPtr->literalTable;
    register LiteralEntry *entryPtr;
    const char *bytes;
    size_t globalHash, length;

    bytes = TclGetStringFromObj(objPtr, &length);
    globalHash = (HashString(bytes, length) & globalTablePtr->mask);
    for (entryPtr=globalTablePtr->buckets[globalHash] ; entryPtr!=NULL;
	    entryPtr=entryPtr->nextPtr) {
	if (entryPtr->objPtr == objPtr) {
	    return entryPtr;
	}
    }
    return NULL;
}

#endif
/*
 *----------------------------------------------------------------------
 *

TclReleaseLiteral(
    Tcl_Interp *interp,		/* Interpreter for which objPtr was created to
				 * hold a literal. */
    register Tcl_Obj *objPtr)	/* Points to a literal object that was
				 * previously created by a call to
				 * TclRegisterLiteral. */
{

    Interp *iPtr = (Interp *) interp;
    LiteralTable *globalTablePtr;
    register LiteralEntry *entryPtr, *prevPtr;
    const char *bytes;
    size_t length, index;

    if (iPtr == NULL) {

#ifdef TCL_COMPILE_STATS
		iPtr->stats.currentLitStringBytes -= (double) (length + 1);
#endif /*TCL_COMPILE_STATS*/
	    }
	    break;
	}
    }


    /*
     * Remove the reference corresponding to the local literal table entry.
     */

    done:
    Tcl_DecrRefCount(objPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * HashString --

 */

void
TclVerifyGlobalLiteralTable(
    Interp *iPtr)		/* Points to interpreter whose global literal
				 * table is to be validated. */
{

    register LiteralTable *globalTablePtr = &iPtr->literalTable;
    register LiteralEntry *globalPtr;
    char *bytes;
    size_t i, length, count = 0;

    for (i=0 ; i<globalTablePtr->numBuckets ; i++) {
	for (globalPtr=globalTablePtr->buckets[i] ; globalPtr!=NULL;

	}
    }
    if (count != globalTablePtr->numEntries) {
	Tcl_Panic("%s: global literal table had %" TCL_Z_MODIFIER "u entries, should be %" TCL_Z_MODIFIER "u",
		"TclVerifyGlobalLiteralTable", count,
		globalTablePtr->numEntries);
    }


}
#endif /*TCL_COMPILE_DEBUG*/

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */