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author | surles <surles@noemail.net> | 1999-05-05 00:35:41 (GMT) |
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committer | surles <surles@noemail.net> | 1999-05-05 00:35:41 (GMT) |
commit | e7d7fd4138278eb7e6c6991bb5eab1c59cef0bdc (patch) | |
tree | 7e11dabefd70e284474ec99e203ff99defba9408 /generic | |
parent | 9f3a6ec35dabd3efd10c13b1abb0e9a716e3823c (diff) | |
download | tcl-e7d7fd4138278eb7e6c6991bb5eab1c59cef0bdc.zip tcl-e7d7fd4138278eb7e6c6991bb5eab1c59cef0bdc.tar.gz tcl-e7d7fd4138278eb7e6c6991bb5eab1c59cef0bdc.tar.bz2 |
fixed memory leak
FossilOrigin-Name: 6ae297a9a4bc7041e9eb85124081183aac52f75e
Diffstat (limited to 'generic')
-rw-r--r-- | generic/tclLiteral.c | 2110 |
1 files changed, 1062 insertions, 1048 deletions
diff --git a/generic/tclLiteral.c b/generic/tclLiteral.c index f180d11..99e46ae 100644 --- a/generic/tclLiteral.c +++ b/generic/tclLiteral.c @@ -1,1048 +1,1062 @@ -/* - * tclLiteral.c -- - * - * Implementation of the global and ByteCode-local literal tables - * used to manage the Tcl objects created for literal values during - * compilation of Tcl scripts. This implementation borrows heavily - * from the more general hashtable implementation of Tcl hash tables - * that appears in tclHash.c. - * - * Copyright (c) 1997-1998 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: tclLiteral.c,v 1.4 1999/04/28 01:56:39 stanton Exp $ - */ - -#include "tclInt.h" -#include "tclCompile.h" - -/* - * When there are this many entries per bucket, on average, rebuild - * a literal's hash table to make it larger. - */ - -#define REBUILD_MULTIPLIER 3 - -/* - * Procedure prototypes for static procedures in this file: - */ - -static int AddLocalLiteralEntry _ANSI_ARGS_(( - CompileEnv *envPtr, LiteralEntry *globalPtr, - int localHash)); -static void ExpandLocalLiteralArray _ANSI_ARGS_(( - CompileEnv *envPtr)); -static unsigned int HashString _ANSI_ARGS_((CONST char *bytes, - int length)); -static void RebuildLiteralTable _ANSI_ARGS_(( - LiteralTable *tablePtr)); - -/* - *---------------------------------------------------------------------- - * - * TclInitLiteralTable -- - * - * This procedure is called to initialize the fields of a literal table - * structure for either an interpreter or a compilation's CompileEnv - * structure. - * - * Results: - * None. - * - * Side effects: - * The literal table is made ready for use. - * - *---------------------------------------------------------------------- - */ - -void -TclInitLiteralTable(tablePtr) - register LiteralTable *tablePtr; /* Pointer to table structure, which - * is supplied by the caller. */ -{ -#if (TCL_SMALL_HASH_TABLE != 4) - panic("TclInitLiteralTable: TCL_SMALL_HASH_TABLE is %d, not 4\n", - TCL_SMALL_HASH_TABLE); -#endif - - tablePtr->buckets = tablePtr->staticBuckets; - tablePtr->staticBuckets[0] = tablePtr->staticBuckets[1] = 0; - tablePtr->staticBuckets[2] = tablePtr->staticBuckets[3] = 0; - tablePtr->numBuckets = TCL_SMALL_HASH_TABLE; - tablePtr->numEntries = 0; - tablePtr->rebuildSize = TCL_SMALL_HASH_TABLE*REBUILD_MULTIPLIER; - tablePtr->mask = 3; -} - -/* - *---------------------------------------------------------------------- - * - * TclDeleteLiteralTable -- - * - * This procedure frees up everything associated with a literal table - * except for the table's structure itself. - * - * Results: - * None. - * - * Side effects: - * Each literal in the table is released: i.e., its reference count - * in the global literal table is decremented and, if it becomes zero, - * the literal is freed. In addition, the table's bucket array is - * freed. - * - *---------------------------------------------------------------------- - */ - -void -TclDeleteLiteralTable(interp, tablePtr) - Tcl_Interp *interp; /* Interpreter containing shared literals - * referenced by the table to delete. */ - LiteralTable *tablePtr; /* Points to the literal table to delete. */ -{ - LiteralEntry *entryPtr; - int i, start; - - /* - * Release remaining literals in the table. Note that releasing a - * literal might release other literals, modifying the table, so we - * restart the search from the bucket chain we last found an entry. - */ - -#ifdef TCL_COMPILE_DEBUG - TclVerifyGlobalLiteralTable((Interp *) interp); -#endif /*TCL_COMPILE_DEBUG*/ - - start = 0; - while (tablePtr->numEntries > 0) { - for (i = start; i < tablePtr->numBuckets; i++) { - entryPtr = tablePtr->buckets[i]; - if (entryPtr != NULL) { - TclReleaseLiteral(interp, entryPtr->objPtr); - start = i; - break; - } - } - } - - /* - * Free up the table's bucket array if it was dynamically allocated. - */ - - if (tablePtr->buckets != tablePtr->staticBuckets) { - ckfree((char *) tablePtr->buckets); - } -} - -/* - *---------------------------------------------------------------------- - * - * TclRegisterLiteral -- - * - * Find, or if necessary create, an object in a CompileEnv literal - * array that has a string representation matching the argument string. - * - * Results: - * The index in the CompileEnv's literal array that references a - * shared literal matching the string. The object is created if - * necessary. - * - * Side effects: - * To maximize sharing, we look up the string in the interpreter's - * global literal table. If not found, we create a new shared literal - * in the global table. We then add a reference to the shared - * literal in the CompileEnv's literal array. - * - * If onHeap is 1, this procedure is given ownership of the string: if - * an object is created then its string representation is set directly - * from string, otherwise the string is freed. Typically, a caller sets - * onHeap 1 if "string" is an already heap-allocated buffer holding the - * result of backslash substitutions. - * - *---------------------------------------------------------------------- - */ - -int -TclRegisterLiteral(envPtr, bytes, length, onHeap) - CompileEnv *envPtr; /* Points to the CompileEnv in whose object - * array an object is found or created. */ - register char *bytes; /* Points to string for which to find or - * create an object in CompileEnv's object - * array. */ - int length; /* Number of bytes in the string. If < 0, - * the string consists of all bytes up to - * the first null character. */ - int onHeap; /* If 1 then the caller already malloc'd - * bytes and ownership is passed to this - * procedure. */ -{ - Interp *iPtr = envPtr->iPtr; - LiteralTable *globalTablePtr = &(iPtr->literalTable); - LiteralTable *localTablePtr = &(envPtr->localLitTable); - register LiteralEntry *globalPtr, *localPtr; - register Tcl_Obj *objPtr; - unsigned int hash; - int localHash, globalHash, objIndex; - long n; - char buf[TCL_INTEGER_SPACE]; - - if (length < 0) { - length = (bytes? strlen(bytes) : 0); - } - hash = HashString(bytes, length); - - /* - * Is the literal already in the CompileEnv's local literal array? - * If so, just return its index. - */ - - localHash = (hash & localTablePtr->mask); - - for (localPtr = localTablePtr->buckets[localHash]; - localPtr != NULL; localPtr = localPtr->nextPtr) { - objPtr = localPtr->objPtr; - if ((objPtr->length == length) && ((length == 0) - || ((objPtr->bytes[0] == bytes[0]) - && (memcmp(objPtr->bytes, bytes, (unsigned) length) - == 0)))) { - if (onHeap) { - ckfree(bytes); - } - objIndex = (localPtr - envPtr->literalArrayPtr); -#ifdef TCL_COMPILE_DEBUG - TclVerifyLocalLiteralTable(envPtr); -#endif /*TCL_COMPILE_DEBUG*/ - return objIndex; - } - } - - /* - * The literal is new to this CompileEnv. Is it in the interpreter's - * global literal table? - */ - - globalHash = (hash & globalTablePtr->mask); - for (globalPtr = globalTablePtr->buckets[globalHash]; - globalPtr != NULL; globalPtr = globalPtr->nextPtr) { - objPtr = globalPtr->objPtr; - if ((objPtr->length == length) && ((length == 0) - || ((objPtr->bytes[0] == bytes[0]) - && (memcmp(objPtr->bytes, bytes, (unsigned) length) - == 0)))) { - /* - * A global literal was found. Add an entry to the CompileEnv's - * local literal array. - */ - - if (onHeap) { - ckfree(bytes); - } - objIndex = AddLocalLiteralEntry(envPtr, globalPtr, localHash); -#ifdef TCL_COMPILE_DEBUG - if (globalPtr->refCount < 1) { - panic("TclRegisterLiteral: global literal \"%.*s\" had bad refCount %d", - (length>60? 60 : length), bytes, - globalPtr->refCount); - } - TclVerifyLocalLiteralTable(envPtr); -#endif /*TCL_COMPILE_DEBUG*/ - return objIndex; - } - } - - /* - * The literal is new to the interpreter. Add it to the global literal - * table then add an entry to the CompileEnv's local literal array. - * Convert the object to an integer object if possible. - */ - - TclNewObj(objPtr); - Tcl_IncrRefCount(objPtr); - if (onHeap) { - objPtr->bytes = bytes; - objPtr->length = length; - } else { - TclInitStringRep(objPtr, bytes, length); - } - if (TclLooksLikeInt(bytes, length)) { - if (TclGetLong((Tcl_Interp *) NULL, bytes, &n) == TCL_OK) { - TclFormatInt(buf, n); - if (strcmp(bytes, buf) == 0) { - objPtr->internalRep.longValue = n; - objPtr->typePtr = &tclIntType; - } - } - } - -#ifdef TCL_COMPILE_DEBUG - if (TclLookupLiteralEntry((Tcl_Interp *) iPtr, objPtr) != NULL) { - panic("TclRegisterLiteral: literal \"%.*s\" found globally but shouldn't be", - (length>60? 60 : length), bytes); - } -#endif - - globalPtr = (LiteralEntry *) ckalloc((unsigned) sizeof(LiteralEntry)); - globalPtr->objPtr = objPtr; - globalPtr->refCount = 0; - 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); - } - - objIndex = AddLocalLiteralEntry(envPtr, globalPtr, localHash); - -#ifdef TCL_COMPILE_DEBUG - TclVerifyGlobalLiteralTable(iPtr); - TclVerifyLocalLiteralTable(envPtr); - { - LiteralEntry *entryPtr; - int found, 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) { - panic("TclRegisterLiteral: literal \"%.*s\" wasn't global", - (length>60? 60 : 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*/ - return objIndex; -} - -/* - *---------------------------------------------------------------------- - * - * TclLookupLiteralEntry -- - * - * Finds the LiteralEntry that corresponds to a literal Tcl object - * holding a literal. - * - * Results: - * Returns the matching LiteralEntry if found, otherwise NULL. - * - * Side effects: - * None. - * - *---------------------------------------------------------------------- - */ - -LiteralEntry * -TclLookupLiteralEntry(interp, objPtr) - 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; - char *bytes; - int length, globalHash; - - bytes = Tcl_GetStringFromObj(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; -} - -/* - *---------------------------------------------------------------------- - * - * TclHideLiteral -- - * - * Remove a literal entry from the literal hash tables, leaving it in - * the literal array so existing references continue to function. - * This makes it possible to turn a shared literal into a private - * literal that cannot be shared. - * - * Results: - * None. - * - * Side effects: - * Removes the literal from the local hash table and decrements the - * global hash entry's reference count. - * - *---------------------------------------------------------------------- - */ - -void -TclHideLiteral(interp, envPtr, index) - Tcl_Interp *interp; /* Interpreter for which objPtr was created - * to hold a literal. */ - register CompileEnv *envPtr; /* Points to CompileEnv whose literal array - * contains the entry being hidden. */ - int index; /* The index of the entry in the literal - * array. */ -{ - LiteralEntry **nextPtrPtr, *entryPtr, *lPtr; - LiteralTable *localTablePtr = &(envPtr->localLitTable); - int localHash, length; - char *bytes; - Tcl_Obj *newObjPtr; - - lPtr = &(envPtr->literalArrayPtr[index]); - - /* - * To avoid unwanted sharing we need to copy the object and remove it from - * the local and global literal tables. It still has a slot in the literal - * array so it can be referred to by byte codes, but it will not be matched - * by literal searches. - */ - - newObjPtr = Tcl_DuplicateObj(lPtr->objPtr); - Tcl_IncrRefCount(newObjPtr); - TclReleaseLiteral(interp, lPtr->objPtr); - lPtr->objPtr = newObjPtr; - - bytes = Tcl_GetStringFromObj(newObjPtr, &length); - localHash = (HashString(bytes, length) & localTablePtr->mask); - nextPtrPtr = &localTablePtr->buckets[localHash]; - - for (entryPtr = *nextPtrPtr; entryPtr != NULL; entryPtr = *nextPtrPtr) { - if (entryPtr == lPtr) { - *nextPtrPtr = lPtr->nextPtr; - lPtr->nextPtr = NULL; - localTablePtr->numEntries--; - break; - } - nextPtrPtr = &entryPtr->nextPtr; - } -} - -/* - *---------------------------------------------------------------------- - * - * TclAddLiteralObj -- - * - * Add a single literal object to the literal array. This - * function does not add the literal to the local or global - * literal tables. The caller is expected to add the entry - * to whatever tables are appropriate. - * - * Results: - * The index in the CompileEnv's literal array that references the - * literal. Stores the pointer to the new literal entry in the - * location referenced by the localPtrPtr argument. - * - * Side effects: - * Expands the literal array if necessary. Increments the refcount - * on the literal object. - * - *---------------------------------------------------------------------- - */ - -int -TclAddLiteralObj(envPtr, objPtr, litPtrPtr) - register CompileEnv *envPtr; /* Points to CompileEnv in whose literal - * array the object is to be inserted. */ - Tcl_Obj *objPtr; /* The object to insert into the array. */ - LiteralEntry **litPtrPtr; /* The location where the pointer to the - * new literal entry should be stored. - * May be NULL. */ -{ - register LiteralEntry *lPtr; - int objIndex; - - if (envPtr->literalArrayNext >= envPtr->literalArrayEnd) { - ExpandLocalLiteralArray(envPtr); - } - objIndex = envPtr->literalArrayNext; - envPtr->literalArrayNext++; - - lPtr = &(envPtr->literalArrayPtr[objIndex]); - lPtr->objPtr = objPtr; - Tcl_IncrRefCount(objPtr); - lPtr->refCount = -1; /* i.e., unused */ - lPtr->nextPtr = NULL; - - if (litPtrPtr) { - *litPtrPtr = lPtr; - } - - return objIndex; -} - -/* - *---------------------------------------------------------------------- - * - * AddLocalLiteralEntry -- - * - * Insert a new literal into a CompileEnv's local literal array. - * - * Results: - * The index in the CompileEnv's literal array that references the - * literal. - * - * Side effects: - * Increments the ref count of the global LiteralEntry since the - * CompileEnv now refers to the literal. Expands the literal array - * if necessary. May rebuild the hash bucket array of the CompileEnv's - * literal array if it becomes too large. - * - *---------------------------------------------------------------------- - */ - -static int -AddLocalLiteralEntry(envPtr, globalPtr, localHash) - register CompileEnv *envPtr; /* Points to CompileEnv in whose literal - * array the object is to be inserted. */ - LiteralEntry *globalPtr; /* Points to the global LiteralEntry for - * the literal to add to the CompileEnv. */ - int localHash; /* Hash value for the literal's string. */ -{ - register LiteralTable *localTablePtr = &(envPtr->localLitTable); - LiteralEntry *localPtr; - int objIndex; - - objIndex = TclAddLiteralObj(envPtr, globalPtr->objPtr, &localPtr); - - /* - * Add the literal to the local table. - */ - - localPtr->nextPtr = localTablePtr->buckets[localHash]; - localTablePtr->buckets[localHash] = localPtr; - localTablePtr->numEntries++; - - globalPtr->refCount++; - - /* - * If the CompileEnv's local literal table has exceeded a decent size, - * rebuild it with more buckets. - */ - - if (localTablePtr->numEntries >= localTablePtr->rebuildSize) { - RebuildLiteralTable(localTablePtr); - } - -#ifdef TCL_COMPILE_DEBUG - TclVerifyLocalLiteralTable(envPtr); - { - char *bytes; - int length, found, i; - found = 0; - for (i = 0; i < localTablePtr->numBuckets; i++) { - for (localPtr = localTablePtr->buckets[i]; - localPtr != NULL; localPtr = localPtr->nextPtr) { - if (localPtr->objPtr == globalPtr->objPtr) { - found = 1; - } - } - } - if (!found) { - bytes = Tcl_GetStringFromObj(globalPtr->objPtr, &length); - panic("AddLocalLiteralEntry: literal \"%.*s\" wasn't found locally", - (length>60? 60 : length), bytes); - } - } -#endif /*TCL_COMPILE_DEBUG*/ - return objIndex; -} - -/* - *---------------------------------------------------------------------- - * - * ExpandLocalLiteralArray -- - * - * Procedure that uses malloc to allocate more storage for a - * CompileEnv's local literal array. - * - * Results: - * None. - * - * Side effects: - * The literal array in *envPtr is reallocated to a new array of - * double the size, and if envPtr->mallocedLiteralArray is non-zero - * the old array is freed. Entries are copied from the old array - * to the new one. The local literal table is updated to refer to - * the new entries. - * - *---------------------------------------------------------------------- - */ - -static void -ExpandLocalLiteralArray(envPtr) - register CompileEnv *envPtr; /* Points to the CompileEnv whose object - * array must be enlarged. */ -{ - /* - * The current allocated local literal entries are stored between - * elements 0 and (envPtr->literalArrayNext - 1) [inclusive]. - */ - - LiteralTable *localTablePtr = &(envPtr->localLitTable); - int currElems = envPtr->literalArrayNext; - size_t currBytes = (currElems * sizeof(LiteralEntry)); - register LiteralEntry *currArrayPtr = envPtr->literalArrayPtr; - register LiteralEntry *newArrayPtr = - (LiteralEntry *) ckalloc((unsigned) (2 * currBytes)); - int i; - - /* - * Copy from the old literal array to the new, then update the local - * literal table's bucket array. - */ - - memcpy((VOID *) newArrayPtr, (VOID *) currArrayPtr, currBytes); - for (i = 0; i < currElems; i++) { - if (currArrayPtr[i].nextPtr == NULL) { - newArrayPtr[i].nextPtr = NULL; - } else { - newArrayPtr[i].nextPtr = newArrayPtr - + (currArrayPtr[i].nextPtr - currArrayPtr); - } - } - for (i = 0; i < localTablePtr->numBuckets; i++) { - if (localTablePtr->buckets[i] != NULL) { - localTablePtr->buckets[i] = newArrayPtr - + (localTablePtr->buckets[i] - currArrayPtr); - } - } - - /* - * Free the old literal array if needed, and mark the new literal - * array as malloced. - */ - - if (envPtr->mallocedLiteralArray) { - ckfree((char *) currArrayPtr); - } - envPtr->literalArrayPtr = newArrayPtr; - envPtr->literalArrayEnd = (2 * currElems); - envPtr->mallocedLiteralArray = 1; -} - -/* - *---------------------------------------------------------------------- - * - * TclReleaseLiteral -- - * - * This procedure releases a reference to one of the shared Tcl objects - * that hold literals. It is called to release the literals referenced - * by a ByteCode that is being destroyed, and it is also called by - * TclDeleteLiteralTable. - * - * Results: - * None. - * - * Side effects: - * The reference count for the global LiteralTable entry that - * corresponds to the literal is decremented. If no other reference - * to a global literal object remains, it is freed. - * - *---------------------------------------------------------------------- - */ - -void -TclReleaseLiteral(interp, objPtr) - 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 = &(iPtr->literalTable); - register LiteralEntry *entryPtr, *prevPtr; - ByteCode* codePtr; - char *bytes; - int length, index; - - bytes = Tcl_GetStringFromObj(objPtr, &length); - index = (HashString(bytes, length) & globalTablePtr->mask); - for (prevPtr = NULL, entryPtr = globalTablePtr->buckets[index]; - entryPtr != NULL; - prevPtr = entryPtr, entryPtr = entryPtr->nextPtr) { - if (entryPtr->objPtr == objPtr) { - entryPtr->refCount--; - - /* - * We found the matching LiteralEntry. Check if it's only being - * kept alive only by a circular reference from a ByteCode - * stored as its internal rep. - */ - - if ((entryPtr->refCount == 1) - && (objPtr->typePtr == &tclByteCodeType)) { - codePtr = (ByteCode *) objPtr->internalRep.otherValuePtr; - if ((codePtr->numLitObjects == 1) - && (codePtr->objArrayPtr[0] == objPtr)) { - entryPtr->refCount = 0; - - /* - * Set the ByteCode object array entry NULL to signal - * to TclCleanupByteCode to not try to release this - * about to be freed literal again. - */ - - codePtr->objArrayPtr[0] = NULL; - } - } - - /* - * If the literal is no longer being used by any ByteCode, - * delete the entry then decrement the ref count of its object. - */ - - if (entryPtr->refCount == 0) { - if (prevPtr == NULL) { - globalTablePtr->buckets[index] = entryPtr->nextPtr; - } else { - prevPtr->nextPtr = entryPtr->nextPtr; - } -#ifdef TCL_COMPILE_STATS - iPtr->stats.currentLitStringBytes -= (double) (length + 1); -#endif /*TCL_COMPILE_STATS*/ - ckfree((char *) entryPtr); - globalTablePtr->numEntries--; - TclDecrRefCount(objPtr); - } - return; - } - } - - /* - * The object wasn't in the literal hash table, so it must be a unique - * local object in the object table that has no global entry. Just - * decrement the refcount and return. - */ - - Tcl_DecrRefCount(objPtr); -} - -/* - *---------------------------------------------------------------------- - * - * HashString -- - * - * Compute a one-word summary of a text string, which can be - * used to generate a hash index. - * - * Results: - * The return value is a one-word summary of the information in - * string. - * - * Side effects: - * None. - * - *---------------------------------------------------------------------- - */ - -static unsigned int -HashString(bytes, length) - register CONST char *bytes; /* String for which to compute hash - * value. */ - int length; /* Number of bytes in the string. */ -{ - register unsigned int result; - register int i; - - /* - * I tried a zillion different hash functions and asked many other - * people for advice. Many people had their own favorite functions, - * all different, but no-one had much idea why they were good ones. - * I chose the one below (multiply by 9 and add new character) - * because of the following reasons: - * - * 1. Multiplying by 10 is perfect for keys that are decimal strings, - * and multiplying by 9 is just about as good. - * 2. Times-9 is (shift-left-3) plus (old). This means that each - * character's bits hang around in the low-order bits of the - * hash value for ever, plus they spread fairly rapidly up to - * the high-order bits to fill out the hash value. This seems - * works well both for decimal and non-decimal strings. - */ - - result = 0; - for (i = 0; i < length; i++) { - result += (result<<3) + *bytes++; - } - return result; -} - -/* - *---------------------------------------------------------------------- - * - * RebuildLiteralTable -- - * - * This procedure is invoked when the ratio of entries to hash buckets - * becomes too large in a local or global literal table. It allocates - * a larger bucket array and moves the entries into the new buckets. - * - * Results: - * None. - * - * Side effects: - * Memory gets reallocated and entries get rehashed into new buckets. - * - *---------------------------------------------------------------------- - */ - -static void -RebuildLiteralTable(tablePtr) - register LiteralTable *tablePtr; /* Local or global table to enlarge. */ -{ - LiteralEntry **oldBuckets; - register LiteralEntry **oldChainPtr, **newChainPtr; - register LiteralEntry *entryPtr; - LiteralEntry **bucketPtr; - char *bytes; - int oldSize, count, index, length; - - oldSize = tablePtr->numBuckets; - oldBuckets = tablePtr->buckets; - - /* - * Allocate and initialize the new bucket array, and set up - * hashing constants for new array size. - */ - - tablePtr->numBuckets *= 4; - tablePtr->buckets = (LiteralEntry **) ckalloc((unsigned) - (tablePtr->numBuckets * sizeof(LiteralEntry *))); - for (count = tablePtr->numBuckets, newChainPtr = tablePtr->buckets; - count > 0; - count--, newChainPtr++) { - *newChainPtr = NULL; - } - tablePtr->rebuildSize *= 4; - tablePtr->mask = (tablePtr->mask << 2) + 3; - - /* - * Rehash all of the existing entries into the new bucket array. - */ - - for (oldChainPtr = oldBuckets; - oldSize > 0; - oldSize--, oldChainPtr++) { - for (entryPtr = *oldChainPtr; entryPtr != NULL; - entryPtr = *oldChainPtr) { - bytes = Tcl_GetStringFromObj(entryPtr->objPtr, &length); - index = (HashString(bytes, length) & tablePtr->mask); - - *oldChainPtr = entryPtr->nextPtr; - bucketPtr = &(tablePtr->buckets[index]); - entryPtr->nextPtr = *bucketPtr; - *bucketPtr = entryPtr; - } - } - - /* - * Free up the old bucket array, if it was dynamically allocated. - */ - - if (oldBuckets != tablePtr->staticBuckets) { - ckfree((char *) oldBuckets); - } -} - -#ifdef TCL_COMPILE_STATS -/* - *---------------------------------------------------------------------- - * - * TclLiteralStats -- - * - * Return statistics describing the layout of the hash table - * in its hash buckets. - * - * Results: - * The return value is a malloc-ed string containing information - * about tablePtr. It is the caller's responsibility to free - * this string. - * - * Side effects: - * None. - * - *---------------------------------------------------------------------- - */ - -char * -TclLiteralStats(tablePtr) - LiteralTable *tablePtr; /* Table for which to produce stats. */ -{ -#define NUM_COUNTERS 10 - int count[NUM_COUNTERS], overflow, i, j; - double average, tmp; - register LiteralEntry *entryPtr; - char *result, *p; - - /* - * Compute a histogram of bucket usage. For each bucket chain i, - * j is the number of entries in the chain. - */ - - for (i = 0; i < NUM_COUNTERS; i++) { - count[i] = 0; - } - overflow = 0; - average = 0.0; - for (i = 0; i < tablePtr->numBuckets; i++) { - j = 0; - for (entryPtr = tablePtr->buckets[i]; entryPtr != NULL; - entryPtr = entryPtr->nextPtr) { - j++; - } - if (j < NUM_COUNTERS) { - count[j]++; - } else { - overflow++; - } - tmp = j; - average += (tmp+1.0)*(tmp/tablePtr->numEntries)/2.0; - } - - /* - * Print out the histogram and a few other pieces of information. - */ - - result = (char *) ckalloc((unsigned) ((NUM_COUNTERS*60) + 300)); - sprintf(result, "%d entries in table, %d buckets\n", - tablePtr->numEntries, tablePtr->numBuckets); - p = result + strlen(result); - for (i = 0; i < NUM_COUNTERS; i++) { - sprintf(p, "number of buckets with %d entries: %d\n", - i, count[i]); - p += strlen(p); - } - sprintf(p, "number of buckets with %d or more entries: %d\n", - NUM_COUNTERS, overflow); - p += strlen(p); - sprintf(p, "average search distance for entry: %.1f", average); - return result; -} -#endif /*TCL_COMPILE_STATS*/ - -#ifdef TCL_COMPILE_DEBUG -/* - *---------------------------------------------------------------------- - * - * TclVerifyLocalLiteralTable -- - * - * Check a CompileEnv's local literal table for consistency. - * - * Results: - * None. - * - * Side effects: - * Panics if problems are found. - * - *---------------------------------------------------------------------- - */ - -void -TclVerifyLocalLiteralTable(envPtr) - CompileEnv *envPtr; /* Points to CompileEnv whose literal - * table is to be validated. */ -{ - register LiteralTable *localTablePtr = &(envPtr->localLitTable); - register LiteralEntry *localPtr; - char *bytes; - register int i; - int length, count; - - count = 0; - for (i = 0; i < localTablePtr->numBuckets; i++) { - for (localPtr = localTablePtr->buckets[i]; - localPtr != NULL; localPtr = localPtr->nextPtr) { - count++; - if (localPtr->refCount != -1) { - bytes = Tcl_GetStringFromObj(localPtr->objPtr, &length); - panic("TclVerifyLocalLiteralTable: local literal \"%.*s\" had bad refCount %d", - (length>60? 60 : length), bytes, - localPtr->refCount); - } - if (TclLookupLiteralEntry((Tcl_Interp *) envPtr->iPtr, - localPtr->objPtr) == NULL) { - bytes = Tcl_GetStringFromObj(localPtr->objPtr, &length); - panic("TclVerifyLocalLiteralTable: local literal \"%.*s\" is not global", - (length>60? 60 : length), bytes); - } - if (localPtr->objPtr->bytes == NULL) { - panic("TclVerifyLocalLiteralTable: literal has NULL string rep"); - } - } - } - if (count != localTablePtr->numEntries) { - panic("TclVerifyLocalLiteralTable: local literal table had %d entries, should be %d", - count, localTablePtr->numEntries); - } -} - -/* - *---------------------------------------------------------------------- - * - * TclVerifyGlobalLiteralTable -- - * - * Check an interpreter's global literal table literal for consistency. - * - * Results: - * None. - * - * Side effects: - * Panics if problems are found. - * - *---------------------------------------------------------------------- - */ - -void -TclVerifyGlobalLiteralTable(iPtr) - Interp *iPtr; /* Points to interpreter whose global - * literal table is to be validated. */ -{ - register LiteralTable *globalTablePtr = &(iPtr->literalTable); - register LiteralEntry *globalPtr; - char *bytes; - register int i; - int length, count; - - count = 0; - for (i = 0; i < globalTablePtr->numBuckets; i++) { - for (globalPtr = globalTablePtr->buckets[i]; - globalPtr != NULL; globalPtr = globalPtr->nextPtr) { - count++; - if (globalPtr->refCount < 1) { - bytes = Tcl_GetStringFromObj(globalPtr->objPtr, &length); - panic("TclVerifyGlobalLiteralTable: global literal \"%.*s\" had bad refCount %d", - (length>60? 60 : length), bytes, - globalPtr->refCount); - } - if (globalPtr->objPtr->bytes == NULL) { - panic("TclVerifyGlobalLiteralTable: literal has NULL string rep"); - } - } - } - if (count != globalTablePtr->numEntries) { - panic("TclVerifyGlobalLiteralTable: global literal table had %d entries, should be %d", - count, globalTablePtr->numEntries); - } -} -#endif /*TCL_COMPILE_DEBUG*/ +/*
+ * tclLiteral.c --
+ *
+ * Implementation of the global and ByteCode-local literal tables
+ * used to manage the Tcl objects created for literal values during
+ * compilation of Tcl scripts. This implementation borrows heavily
+ * from the more general hashtable implementation of Tcl hash tables
+ * that appears in tclHash.c.
+ *
+ * Copyright (c) 1997-1998 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: tclLiteral.c,v 1.5 1999/05/05 00:35:41 surles Exp $
+ */
+
+#include "tclInt.h"
+#include "tclCompile.h"
+#include "tclPort.h"
+/*
+ * When there are this many entries per bucket, on average, rebuild
+ * a literal's hash table to make it larger.
+ */
+
+#define REBUILD_MULTIPLIER 3
+
+/*
+ * Procedure prototypes for static procedures in this file:
+ */
+
+static int AddLocalLiteralEntry _ANSI_ARGS_((
+ CompileEnv *envPtr, LiteralEntry *globalPtr,
+ int localHash));
+static void ExpandLocalLiteralArray _ANSI_ARGS_((
+ CompileEnv *envPtr));
+static unsigned int HashString _ANSI_ARGS_((CONST char *bytes,
+ int length));
+static void RebuildLiteralTable _ANSI_ARGS_((
+ LiteralTable *tablePtr));
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclInitLiteralTable --
+ *
+ * This procedure is called to initialize the fields of a literal table
+ * structure for either an interpreter or a compilation's CompileEnv
+ * structure.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * The literal table is made ready for use.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclInitLiteralTable(tablePtr)
+ register LiteralTable *tablePtr; /* Pointer to table structure, which
+ * is supplied by the caller. */
+{
+#if (TCL_SMALL_HASH_TABLE != 4)
+ panic("TclInitLiteralTable: TCL_SMALL_HASH_TABLE is %d, not 4\n",
+ TCL_SMALL_HASH_TABLE);
+#endif
+
+ tablePtr->buckets = tablePtr->staticBuckets;
+ tablePtr->staticBuckets[0] = tablePtr->staticBuckets[1] = 0;
+ tablePtr->staticBuckets[2] = tablePtr->staticBuckets[3] = 0;
+ tablePtr->numBuckets = TCL_SMALL_HASH_TABLE;
+ tablePtr->numEntries = 0;
+ tablePtr->rebuildSize = TCL_SMALL_HASH_TABLE*REBUILD_MULTIPLIER;
+ tablePtr->mask = 3;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclDeleteLiteralTable --
+ *
+ * This procedure frees up everything associated with a literal table
+ * except for the table's structure itself.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * Each literal in the table is released: i.e., its reference count
+ * in the global literal table is decremented and, if it becomes zero,
+ * the literal is freed. In addition, the table's bucket array is
+ * freed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclDeleteLiteralTable(interp, tablePtr)
+ Tcl_Interp *interp; /* Interpreter containing shared literals
+ * referenced by the table to delete. */
+ LiteralTable *tablePtr; /* Points to the literal table to delete. */
+{
+ LiteralEntry *entryPtr;
+ int i, start;
+
+ /*
+ * Release remaining literals in the table. Note that releasing a
+ * literal might release other literals, modifying the table, so we
+ * restart the search from the bucket chain we last found an entry.
+ */
+
+#ifdef TCL_COMPILE_DEBUG
+ TclVerifyGlobalLiteralTable((Interp *) interp);
+#endif /*TCL_COMPILE_DEBUG*/
+
+ start = 0;
+ while (tablePtr->numEntries > 0) {
+ for (i = start; i < tablePtr->numBuckets; i++) {
+ entryPtr = tablePtr->buckets[i];
+ if (entryPtr != NULL) {
+ TclReleaseLiteral(interp, entryPtr->objPtr);
+ start = i;
+ break;
+ }
+ }
+ }
+
+ /*
+ * Free up the table's bucket array if it was dynamically allocated.
+ */
+
+ if (tablePtr->buckets != tablePtr->staticBuckets) {
+ ckfree((char *) tablePtr->buckets);
+ }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclRegisterLiteral --
+ *
+ * Find, or if necessary create, an object in a CompileEnv literal
+ * array that has a string representation matching the argument string.
+ *
+ * Results:
+ * The index in the CompileEnv's literal array that references a
+ * shared literal matching the string. The object is created if
+ * necessary.
+ *
+ * Side effects:
+ * To maximize sharing, we look up the string in the interpreter's
+ * global literal table. If not found, we create a new shared literal
+ * in the global table. We then add a reference to the shared
+ * literal in the CompileEnv's literal array.
+ *
+ * If onHeap is 1, this procedure is given ownership of the string: if
+ * an object is created then its string representation is set directly
+ * from string, otherwise the string is freed. Typically, a caller sets
+ * onHeap 1 if "string" is an already heap-allocated buffer holding the
+ * result of backslash substitutions.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclRegisterLiteral(envPtr, bytes, length, onHeap)
+ CompileEnv *envPtr; /* Points to the CompileEnv in whose object
+ * array an object is found or created. */
+ register char *bytes; /* Points to string for which to find or
+ * create an object in CompileEnv's object
+ * array. */
+ int length; /* Number of bytes in the string. If < 0,
+ * the string consists of all bytes up to
+ * the first null character. */
+ int onHeap; /* If 1 then the caller already malloc'd
+ * bytes and ownership is passed to this
+ * procedure. */
+{
+ Interp *iPtr = envPtr->iPtr;
+ LiteralTable *globalTablePtr = &(iPtr->literalTable);
+ LiteralTable *localTablePtr = &(envPtr->localLitTable);
+ register LiteralEntry *globalPtr, *localPtr;
+ register Tcl_Obj *objPtr;
+ unsigned int hash;
+ int localHash, globalHash, objIndex;
+ long n;
+ char buf[TCL_INTEGER_SPACE];
+
+
+ if (length < 0) {
+ length = (bytes? strlen(bytes) : 0);
+ }
+ hash = HashString(bytes, length);
+
+ /*
+ * Is the literal already in the CompileEnv's local literal array?
+ * If so, just return its index.
+ */
+
+ localHash = (hash & localTablePtr->mask);
+ for (localPtr = localTablePtr->buckets[localHash];
+ localPtr != NULL; localPtr = localPtr->nextPtr) {
+ objPtr = localPtr->objPtr;
+ if ((objPtr->length == length) && ((length == 0)
+ || ((objPtr->bytes[0] == bytes[0])
+ && (memcmp(objPtr->bytes, bytes, (unsigned) length)
+ == 0)))) {
+ if (onHeap) {
+ ckfree(bytes);
+ }
+ objIndex = (localPtr - envPtr->literalArrayPtr);
+#ifdef TCL_COMPILE_DEBUG
+ TclVerifyLocalLiteralTable(envPtr);
+#endif /*TCL_COMPILE_DEBUG*/
+
+ return objIndex;
+ }
+ }
+
+ /*
+ * The literal is new to this CompileEnv. Is it in the interpreter's
+ * global literal table?
+ */
+
+ globalHash = (hash & globalTablePtr->mask);
+ for (globalPtr = globalTablePtr->buckets[globalHash];
+ globalPtr != NULL; globalPtr = globalPtr->nextPtr) {
+ objPtr = globalPtr->objPtr;
+ if ((objPtr->length == length) && ((length == 0)
+ || ((objPtr->bytes[0] == bytes[0])
+ && (memcmp(objPtr->bytes, bytes, (unsigned) length)
+ == 0)))) {
+ /*
+ * A global literal was found. Add an entry to the CompileEnv's
+ * local literal array.
+ */
+
+ if (onHeap) {
+ ckfree(bytes);
+ }
+ objIndex = AddLocalLiteralEntry(envPtr, globalPtr, localHash);
+#ifdef TCL_COMPILE_DEBUG
+ if (globalPtr->refCount < 1) {
+ panic("TclRegisterLiteral: global literal \"%.*s\" had bad refCount %d",
+ (length>60? 60 : length), bytes,
+ globalPtr->refCount);
+ }
+ TclVerifyLocalLiteralTable(envPtr);
+#endif /*TCL_COMPILE_DEBUG*/
+ return objIndex;
+ }
+ }
+
+ /*
+ * The literal is new to the interpreter. Add it to the global literal
+ * table then add an entry to the CompileEnv's local literal array.
+ * Convert the object to an integer object if possible.
+ */
+
+ TclNewObj(objPtr);
+ Tcl_IncrRefCount(objPtr);
+ if (onHeap) {
+ objPtr->bytes = bytes;
+ objPtr->length = length;
+ } else {
+ TclInitStringRep(objPtr, bytes, length);
+ }
+
+ if (TclLooksLikeInt(bytes, length)) {
+ if (TclGetLong((Tcl_Interp *) NULL, bytes, &n) == TCL_OK) {
+ TclFormatInt(buf, n);
+ if (strcmp(bytes, buf) == 0) {
+ objPtr->internalRep.longValue = n;
+ objPtr->typePtr = &tclIntType;
+ }
+ }
+ }
+
+#ifdef TCL_COMPILE_DEBUG
+ if (TclLookupLiteralEntry((Tcl_Interp *) iPtr, objPtr) != NULL) {
+ panic("TclRegisterLiteral: literal \"%.*s\" found globally but shouldn't be",
+ (length>60? 60 : length), bytes);
+ }
+#endif
+
+ globalPtr = (LiteralEntry *) ckalloc((unsigned) sizeof(LiteralEntry));
+ globalPtr->objPtr = objPtr;
+ globalPtr->refCount = 0;
+ 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);
+ }
+
+ objIndex = AddLocalLiteralEntry(envPtr, globalPtr, localHash);
+
+#ifdef TCL_COMPILE_DEBUG
+ TclVerifyGlobalLiteralTable(iPtr);
+ TclVerifyLocalLiteralTable(envPtr);
+ {
+ LiteralEntry *entryPtr;
+ int found, 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) {
+ panic("TclRegisterLiteral: literal \"%.*s\" wasn't global",
+ (length>60? 60 : 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*/
+ return objIndex;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclLookupLiteralEntry --
+ *
+ * Finds the LiteralEntry that corresponds to a literal Tcl object
+ * holding a literal.
+ *
+ * Results:
+ * Returns the matching LiteralEntry if found, otherwise NULL.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+LiteralEntry *
+TclLookupLiteralEntry(interp, objPtr)
+ 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;
+ char *bytes;
+ int length, globalHash;
+
+ bytes = Tcl_GetStringFromObj(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;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclHideLiteral --
+ *
+ * Remove a literal entry from the literal hash tables, leaving it in
+ * the literal array so existing references continue to function.
+ * This makes it possible to turn a shared literal into a private
+ * literal that cannot be shared.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * Removes the literal from the local hash table and decrements the
+ * global hash entry's reference count.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclHideLiteral(interp, envPtr, index)
+ Tcl_Interp *interp; /* Interpreter for which objPtr was created
+ * to hold a literal. */
+ register CompileEnv *envPtr; /* Points to CompileEnv whose literal array
+ * contains the entry being hidden. */
+ int index; /* The index of the entry in the literal
+ * array. */
+{
+ LiteralEntry **nextPtrPtr, *entryPtr, *lPtr;
+ LiteralTable *localTablePtr = &(envPtr->localLitTable);
+ int localHash, length;
+ char *bytes;
+ Tcl_Obj *newObjPtr;
+
+ lPtr = &(envPtr->literalArrayPtr[index]);
+
+ /*
+ * To avoid unwanted sharing we need to copy the object and remove it from
+ * the local and global literal tables. It still has a slot in the literal
+ * array so it can be referred to by byte codes, but it will not be matched
+ * by literal searches.
+ */
+
+ newObjPtr = Tcl_DuplicateObj(lPtr->objPtr);
+ Tcl_IncrRefCount(newObjPtr);
+ TclReleaseLiteral(interp, lPtr->objPtr);
+ lPtr->objPtr = newObjPtr;
+
+ bytes = Tcl_GetStringFromObj(newObjPtr, &length);
+ localHash = (HashString(bytes, length) & localTablePtr->mask);
+ nextPtrPtr = &localTablePtr->buckets[localHash];
+
+ for (entryPtr = *nextPtrPtr; entryPtr != NULL; entryPtr = *nextPtrPtr) {
+ if (entryPtr == lPtr) {
+ *nextPtrPtr = lPtr->nextPtr;
+ lPtr->nextPtr = NULL;
+ localTablePtr->numEntries--;
+ break;
+ }
+ nextPtrPtr = &entryPtr->nextPtr;
+ }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclAddLiteralObj --
+ *
+ * Add a single literal object to the literal array. This
+ * function does not add the literal to the local or global
+ * literal tables. The caller is expected to add the entry
+ * to whatever tables are appropriate.
+ *
+ * Results:
+ * The index in the CompileEnv's literal array that references the
+ * literal. Stores the pointer to the new literal entry in the
+ * location referenced by the localPtrPtr argument.
+ *
+ * Side effects:
+ * Expands the literal array if necessary. Increments the refcount
+ * on the literal object.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclAddLiteralObj(envPtr, objPtr, litPtrPtr)
+ register CompileEnv *envPtr; /* Points to CompileEnv in whose literal
+ * array the object is to be inserted. */
+ Tcl_Obj *objPtr; /* The object to insert into the array. */
+ LiteralEntry **litPtrPtr; /* The location where the pointer to the
+ * new literal entry should be stored.
+ * May be NULL. */
+{
+ register LiteralEntry *lPtr;
+ int objIndex;
+
+ if (envPtr->literalArrayNext >= envPtr->literalArrayEnd) {
+ ExpandLocalLiteralArray(envPtr);
+ }
+ objIndex = envPtr->literalArrayNext;
+ envPtr->literalArrayNext++;
+
+ lPtr = &(envPtr->literalArrayPtr[objIndex]);
+ lPtr->objPtr = objPtr;
+ Tcl_IncrRefCount(objPtr);
+ lPtr->refCount = -1; /* i.e., unused */
+ lPtr->nextPtr = NULL;
+
+ if (litPtrPtr) {
+ *litPtrPtr = lPtr;
+ }
+
+ return objIndex;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AddLocalLiteralEntry --
+ *
+ * Insert a new literal into a CompileEnv's local literal array.
+ *
+ * Results:
+ * The index in the CompileEnv's literal array that references the
+ * literal.
+ *
+ * Side effects:
+ * Increments the ref count of the global LiteralEntry since the
+ * CompileEnv now refers to the literal. Expands the literal array
+ * if necessary. May rebuild the hash bucket array of the CompileEnv's
+ * literal array if it becomes too large.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+AddLocalLiteralEntry(envPtr, globalPtr, localHash)
+ register CompileEnv *envPtr; /* Points to CompileEnv in whose literal
+ * array the object is to be inserted. */
+ LiteralEntry *globalPtr; /* Points to the global LiteralEntry for
+ * the literal to add to the CompileEnv. */
+ int localHash; /* Hash value for the literal's string. */
+{
+ register LiteralTable *localTablePtr = &(envPtr->localLitTable);
+ LiteralEntry *localPtr;
+ int objIndex;
+
+ objIndex = TclAddLiteralObj(envPtr, globalPtr->objPtr, &localPtr);
+
+ /*
+ * Add the literal to the local table.
+ */
+
+ localPtr->nextPtr = localTablePtr->buckets[localHash];
+ localTablePtr->buckets[localHash] = localPtr;
+ localTablePtr->numEntries++;
+
+ globalPtr->refCount++;
+
+ /*
+ * If the CompileEnv's local literal table has exceeded a decent size,
+ * rebuild it with more buckets.
+ */
+
+ if (localTablePtr->numEntries >= localTablePtr->rebuildSize) {
+ RebuildLiteralTable(localTablePtr);
+ }
+
+#ifdef TCL_COMPILE_DEBUG
+ TclVerifyLocalLiteralTable(envPtr);
+ {
+ char *bytes;
+ int length, found, i;
+ found = 0;
+ for (i = 0; i < localTablePtr->numBuckets; i++) {
+ for (localPtr = localTablePtr->buckets[i];
+ localPtr != NULL; localPtr = localPtr->nextPtr) {
+ if (localPtr->objPtr == globalPtr->objPtr) {
+ found = 1;
+ }
+ }
+ }
+ if (!found) {
+ bytes = Tcl_GetStringFromObj(globalPtr->objPtr, &length);
+ panic("AddLocalLiteralEntry: literal \"%.*s\" wasn't found locally",
+ (length>60? 60 : length), bytes);
+ }
+ }
+#endif /*TCL_COMPILE_DEBUG*/
+ return objIndex;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * ExpandLocalLiteralArray --
+ *
+ * Procedure that uses malloc to allocate more storage for a
+ * CompileEnv's local literal array.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * The literal array in *envPtr is reallocated to a new array of
+ * double the size, and if envPtr->mallocedLiteralArray is non-zero
+ * the old array is freed. Entries are copied from the old array
+ * to the new one. The local literal table is updated to refer to
+ * the new entries.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+ExpandLocalLiteralArray(envPtr)
+ register CompileEnv *envPtr; /* Points to the CompileEnv whose object
+ * array must be enlarged. */
+{
+ /*
+ * The current allocated local literal entries are stored between
+ * elements 0 and (envPtr->literalArrayNext - 1) [inclusive].
+ */
+
+ LiteralTable *localTablePtr = &(envPtr->localLitTable);
+ int currElems = envPtr->literalArrayNext;
+ size_t currBytes = (currElems * sizeof(LiteralEntry));
+ register LiteralEntry *currArrayPtr = envPtr->literalArrayPtr;
+ register LiteralEntry *newArrayPtr =
+ (LiteralEntry *) ckalloc((unsigned) (2 * currBytes));
+ int i;
+
+ /*
+ * Copy from the old literal array to the new, then update the local
+ * literal table's bucket array.
+ */
+
+ memcpy((VOID *) newArrayPtr, (VOID *) currArrayPtr, currBytes);
+ for (i = 0; i < currElems; i++) {
+ if (currArrayPtr[i].nextPtr == NULL) {
+ newArrayPtr[i].nextPtr = NULL;
+ } else {
+ newArrayPtr[i].nextPtr = newArrayPtr
+ + (currArrayPtr[i].nextPtr - currArrayPtr);
+ }
+ }
+ for (i = 0; i < localTablePtr->numBuckets; i++) {
+ if (localTablePtr->buckets[i] != NULL) {
+ localTablePtr->buckets[i] = newArrayPtr
+ + (localTablePtr->buckets[i] - currArrayPtr);
+ }
+ }
+
+ /*
+ * Free the old literal array if needed, and mark the new literal
+ * array as malloced.
+ */
+
+ if (envPtr->mallocedLiteralArray) {
+ ckfree((char *) currArrayPtr);
+ }
+ envPtr->literalArrayPtr = newArrayPtr;
+ envPtr->literalArrayEnd = (2 * currElems);
+ envPtr->mallocedLiteralArray = 1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclReleaseLiteral --
+ *
+ * This procedure releases a reference to one of the shared Tcl objects
+ * that hold literals. It is called to release the literals referenced
+ * by a ByteCode that is being destroyed, and it is also called by
+ * TclDeleteLiteralTable.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * The reference count for the global LiteralTable entry that
+ * corresponds to the literal is decremented. If no other reference
+ * to a global literal object remains, it is freed.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclReleaseLiteral(interp, objPtr)
+ 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 = &(iPtr->literalTable);
+ register LiteralEntry *entryPtr, *prevPtr;
+ ByteCode* codePtr;
+ char *bytes;
+ int length, index;
+
+ bytes = Tcl_GetStringFromObj(objPtr, &length);
+ index = (HashString(bytes, length) & globalTablePtr->mask);
+
+ /*
+ * Check to see if the object is in the global literal table and
+ * remove this reference. The object may not be in the table if
+ * it is a hidden local literal.
+ */
+
+ for (prevPtr = NULL, entryPtr = globalTablePtr->buckets[index];
+ entryPtr != NULL;
+ prevPtr = entryPtr, entryPtr = entryPtr->nextPtr) {
+ if (entryPtr->objPtr == objPtr) {
+ entryPtr->refCount--;
+
+ /*
+ * We found the matching LiteralEntry. Check if it's only being
+ * kept alive only by a circular reference from a ByteCode
+ * stored as its internal rep.
+ */
+
+ if ((entryPtr->refCount == 1)
+ && (objPtr->typePtr == &tclByteCodeType)) {
+ codePtr = (ByteCode *) objPtr->internalRep.otherValuePtr;
+ if ((codePtr->numLitObjects == 1)
+ && (codePtr->objArrayPtr[0] == objPtr)) {
+ entryPtr->refCount = 0;
+
+ /*
+ * Set the ByteCode object array entry NULL to signal
+ * to TclCleanupByteCode to not try to release this
+ * about to be freed literal again.
+ */
+
+ codePtr->objArrayPtr[0] = NULL;
+ }
+ }
+
+ /*
+ * If the literal is no longer being used by any ByteCode,
+ * delete the entry then decrement the ref count of its object.
+ */
+
+ if (entryPtr->refCount == 0) {
+ if (prevPtr == NULL) {
+ globalTablePtr->buckets[index] = entryPtr->nextPtr;
+ } else {
+ prevPtr->nextPtr = entryPtr->nextPtr;
+ }
+#ifdef TCL_COMPILE_STATS
+ iPtr->stats.currentLitStringBytes -= (double) (length + 1);
+#endif /*TCL_COMPILE_STATS*/
+ ckfree((char *) entryPtr);
+ globalTablePtr->numEntries--;
+
+ /*
+ * Remove the reference corresponding to the global
+ * literal table entry.
+ */
+
+ TclDecrRefCount(objPtr);
+ }
+ break;
+ }
+ }
+
+ /*
+ * Remove the reference corresponding to the local literal table
+ * entry.
+ */
+
+ Tcl_DecrRefCount(objPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * HashString --
+ *
+ * Compute a one-word summary of a text string, which can be
+ * used to generate a hash index.
+ *
+ * Results:
+ * The return value is a one-word summary of the information in
+ * string.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static unsigned int
+HashString(bytes, length)
+ register CONST char *bytes; /* String for which to compute hash
+ * value. */
+ int length; /* Number of bytes in the string. */
+{
+ register unsigned int result;
+ register int i;
+
+ /*
+ * I tried a zillion different hash functions and asked many other
+ * people for advice. Many people had their own favorite functions,
+ * all different, but no-one had much idea why they were good ones.
+ * I chose the one below (multiply by 9 and add new character)
+ * because of the following reasons:
+ *
+ * 1. Multiplying by 10 is perfect for keys that are decimal strings,
+ * and multiplying by 9 is just about as good.
+ * 2. Times-9 is (shift-left-3) plus (old). This means that each
+ * character's bits hang around in the low-order bits of the
+ * hash value for ever, plus they spread fairly rapidly up to
+ * the high-order bits to fill out the hash value. This seems
+ * works well both for decimal and non-decimal strings.
+ */
+
+ result = 0;
+ for (i = 0; i < length; i++) {
+ result += (result<<3) + *bytes++;
+ }
+ return result;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * RebuildLiteralTable --
+ *
+ * This procedure is invoked when the ratio of entries to hash buckets
+ * becomes too large in a local or global literal table. It allocates
+ * a larger bucket array and moves the entries into the new buckets.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * Memory gets reallocated and entries get rehashed into new buckets.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+RebuildLiteralTable(tablePtr)
+ register LiteralTable *tablePtr; /* Local or global table to enlarge. */
+{
+ LiteralEntry **oldBuckets;
+ register LiteralEntry **oldChainPtr, **newChainPtr;
+ register LiteralEntry *entryPtr;
+ LiteralEntry **bucketPtr;
+ char *bytes;
+ int oldSize, count, index, length;
+
+ oldSize = tablePtr->numBuckets;
+ oldBuckets = tablePtr->buckets;
+
+ /*
+ * Allocate and initialize the new bucket array, and set up
+ * hashing constants for new array size.
+ */
+
+ tablePtr->numBuckets *= 4;
+ tablePtr->buckets = (LiteralEntry **) ckalloc((unsigned)
+ (tablePtr->numBuckets * sizeof(LiteralEntry *)));
+ for (count = tablePtr->numBuckets, newChainPtr = tablePtr->buckets;
+ count > 0;
+ count--, newChainPtr++) {
+ *newChainPtr = NULL;
+ }
+ tablePtr->rebuildSize *= 4;
+ tablePtr->mask = (tablePtr->mask << 2) + 3;
+
+ /*
+ * Rehash all of the existing entries into the new bucket array.
+ */
+
+ for (oldChainPtr = oldBuckets;
+ oldSize > 0;
+ oldSize--, oldChainPtr++) {
+ for (entryPtr = *oldChainPtr; entryPtr != NULL;
+ entryPtr = *oldChainPtr) {
+ bytes = Tcl_GetStringFromObj(entryPtr->objPtr, &length);
+ index = (HashString(bytes, length) & tablePtr->mask);
+
+ *oldChainPtr = entryPtr->nextPtr;
+ bucketPtr = &(tablePtr->buckets[index]);
+ entryPtr->nextPtr = *bucketPtr;
+ *bucketPtr = entryPtr;
+ }
+ }
+
+ /*
+ * Free up the old bucket array, if it was dynamically allocated.
+ */
+
+ if (oldBuckets != tablePtr->staticBuckets) {
+ ckfree((char *) oldBuckets);
+ }
+}
+
+#ifdef TCL_COMPILE_STATS
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclLiteralStats --
+ *
+ * Return statistics describing the layout of the hash table
+ * in its hash buckets.
+ *
+ * Results:
+ * The return value is a malloc-ed string containing information
+ * about tablePtr. It is the caller's responsibility to free
+ * this string.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+char *
+TclLiteralStats(tablePtr)
+ LiteralTable *tablePtr; /* Table for which to produce stats. */
+{
+#define NUM_COUNTERS 10
+ int count[NUM_COUNTERS], overflow, i, j;
+ double average, tmp;
+ register LiteralEntry *entryPtr;
+ char *result, *p;
+
+ /*
+ * Compute a histogram of bucket usage. For each bucket chain i,
+ * j is the number of entries in the chain.
+ */
+
+ for (i = 0; i < NUM_COUNTERS; i++) {
+ count[i] = 0;
+ }
+ overflow = 0;
+ average = 0.0;
+ for (i = 0; i < tablePtr->numBuckets; i++) {
+ j = 0;
+ for (entryPtr = tablePtr->buckets[i]; entryPtr != NULL;
+ entryPtr = entryPtr->nextPtr) {
+ j++;
+ }
+ if (j < NUM_COUNTERS) {
+ count[j]++;
+ } else {
+ overflow++;
+ }
+ tmp = j;
+ average += (tmp+1.0)*(tmp/tablePtr->numEntries)/2.0;
+ }
+
+ /*
+ * Print out the histogram and a few other pieces of information.
+ */
+
+ result = (char *) ckalloc((unsigned) ((NUM_COUNTERS*60) + 300));
+ sprintf(result, "%d entries in table, %d buckets\n",
+ tablePtr->numEntries, tablePtr->numBuckets);
+ p = result + strlen(result);
+ for (i = 0; i < NUM_COUNTERS; i++) {
+ sprintf(p, "number of buckets with %d entries: %d\n",
+ i, count[i]);
+ p += strlen(p);
+ }
+ sprintf(p, "number of buckets with %d or more entries: %d\n",
+ NUM_COUNTERS, overflow);
+ p += strlen(p);
+ sprintf(p, "average search distance for entry: %.1f", average);
+ return result;
+}
+#endif /*TCL_COMPILE_STATS*/
+
+#ifdef TCL_COMPILE_DEBUG
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclVerifyLocalLiteralTable --
+ *
+ * Check a CompileEnv's local literal table for consistency.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * Panics if problems are found.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclVerifyLocalLiteralTable(envPtr)
+ CompileEnv *envPtr; /* Points to CompileEnv whose literal
+ * table is to be validated. */
+{
+ register LiteralTable *localTablePtr = &(envPtr->localLitTable);
+ register LiteralEntry *localPtr;
+ char *bytes;
+ register int i;
+ int length, count;
+
+ count = 0;
+ for (i = 0; i < localTablePtr->numBuckets; i++) {
+ for (localPtr = localTablePtr->buckets[i];
+ localPtr != NULL; localPtr = localPtr->nextPtr) {
+ count++;
+ if (localPtr->refCount != -1) {
+ bytes = Tcl_GetStringFromObj(localPtr->objPtr, &length);
+ panic("TclVerifyLocalLiteralTable: local literal \"%.*s\" had bad refCount %d",
+ (length>60? 60 : length), bytes,
+ localPtr->refCount);
+ }
+ if (TclLookupLiteralEntry((Tcl_Interp *) envPtr->iPtr,
+ localPtr->objPtr) == NULL) {
+ bytes = Tcl_GetStringFromObj(localPtr->objPtr, &length);
+ panic("TclVerifyLocalLiteralTable: local literal \"%.*s\" is not global",
+ (length>60? 60 : length), bytes);
+ }
+ if (localPtr->objPtr->bytes == NULL) {
+ panic("TclVerifyLocalLiteralTable: literal has NULL string rep");
+ }
+ }
+ }
+ if (count != localTablePtr->numEntries) {
+ panic("TclVerifyLocalLiteralTable: local literal table had %d entries, should be %d",
+ count, localTablePtr->numEntries);
+ }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclVerifyGlobalLiteralTable --
+ *
+ * Check an interpreter's global literal table literal for consistency.
+ *
+ * Results:
+ * None.
+ *
+ * Side effects:
+ * Panics if problems are found.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TclVerifyGlobalLiteralTable(iPtr)
+ Interp *iPtr; /* Points to interpreter whose global
+ * literal table is to be validated. */
+{
+ register LiteralTable *globalTablePtr = &(iPtr->literalTable);
+ register LiteralEntry *globalPtr;
+ char *bytes;
+ register int i;
+ int length, count;
+
+ count = 0;
+ for (i = 0; i < globalTablePtr->numBuckets; i++) {
+ for (globalPtr = globalTablePtr->buckets[i];
+ globalPtr != NULL; globalPtr = globalPtr->nextPtr) {
+ count++;
+ if (globalPtr->refCount < 1) {
+ bytes = Tcl_GetStringFromObj(globalPtr->objPtr, &length);
+ panic("TclVerifyGlobalLiteralTable: global literal \"%.*s\" had bad refCount %d",
+ (length>60? 60 : length), bytes,
+ globalPtr->refCount);
+ }
+ if (globalPtr->objPtr->bytes == NULL) {
+ panic("TclVerifyGlobalLiteralTable: literal has NULL string rep");
+ }
+ }
+ }
+ if (count != globalTablePtr->numEntries) {
+ panic("TclVerifyGlobalLiteralTable: global literal table had %d entries, should be %d",
+ count, globalTablePtr->numEntries);
+ }
+}
+#endif /*TCL_COMPILE_DEBUG*/
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