Add a linked list of ParseCleanup objects to the end of a Parse object and

use that list as a place to put other sub-objects that need to be deallocated.
Have a single such list for infrequently used sub-objects is more efficient
than doing an a separate check for each kind of sub-object.

FossilOrigin-Name: affa2b7b316941b8a6c4d0d1ff212c81a593faf1d05d129e14d2b70d73a25c59

manifest

@@ -1,5 +1,5 @@
-C New\sCLI\scommand:\s\s".stats\svmstep"\senables\sthe\sdisplay\sof\sthe\svirtual-machine\nstep\scount\sonly,\safter\seach\scommand.\s\sUseful\sfor\soptimization\sproblems.
+C Add\sa\slinked\slist\sof\sParseCleanup\sobjects\sto\sthe\send\sof\sa\sParse\sobject\sand\nuse\sthat\slist\sas\sa\splace\sto\sput\sother\ssub-objects\sthat\sneed\sto\sbe\sdeallocated.\nHave\sa\ssingle\ssuch\slist\sfor\sinfrequently\sused\ssub-objects\sis\smore\sefficient\nthan\sdoing\san\sa\sseparate\scheck\sfor\seach\skind\sof\ssub-object.
-D 2021-01-09T19:10:04.989
+D 2021-01-11T20:37:02.868
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -501,7 +501,7 @@ F src/hash.c 8d7dda241d0ebdafb6ffdeda3149a412d7df75102cecfc1021c98d6219823b19
 F src/hash.h 9d56a9079d523b648774c1784b74b89bd93fac7b365210157482e4319a468f38
 F src/hwtime.h cb1d7e3e1ed94b7aa6fde95ae2c2daccc3df826be26fc9ed7fd90d1750ae6144
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
-F src/insert.c 81b7ee72cd754b5d0018659d5593355f2d61b3d80f07f200167c4826846e907d
+F src/insert.c 9ced988440d29531568bfe4f48c7b69035b100f6833ca1080abb710b7c415111
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 8c9c8cd2bd8eecdb06d9b6e89de7e9e65bae45cc8fc33609cc74023a5c296067
 F src/main.c 97e9f137354bc1f76dc9bb60a0a24f8c45cf73b33e80d3ee4c64155336fb820d
@@ -535,17 +535,17 @@ F src/pcache.h 4f87acd914cef5016fae3030343540d75f5b85a1877eed1a2a19b9f284248586
 F src/pcache1.c 6596e10baf3d8f84cc1585d226cf1ab26564a5f5caf85a15757a281ff977d51a
 F src/pragma.c 6daaaecc26a4b09481d21722525b079ce756751a43a79cc1d8f122d686806193
 F src/pragma.h 8dc78ab7e9ec6ce3ded8332810a2066f1ef6267e2e03cd7356ee00276125c6cf
-F src/prepare.c a6bac9100b5f171189f6bb7ee12dfeeda7f3a8fd0c89be4a7958f14df13fa746
+F src/prepare.c 1f8bb4f20d83024194780f28920c6af9cfe52adc772ded8f33b4ee2b66f46f66
 F src/printf.c 30e92b638fac71dcd85cdea1d12ecfae354c9adee2c71e8e1ae4727cde7c91ed
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
 F src/resolve.c 1948a92ca9eab776632816b97e57c61d933474a78aad4f4ef835c916a83dbb1c
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c 85c7cec9a4a983416d4bd023b2c4fbbeb608ae8dfb069781f80c8ed08b0c7a7c
+F src/select.c b7281a798ee02cb356d2d8b7381939cb513646a91210478587ed6f7f33c357a8
 F src/shell.c.in 79bceb990e4bac23a09bb8dd65783ea4867b8bfca9242b5a82b884043e65109a
 F src/sqlite.h.in 0af968a1fa3c717261e1df0ed105fa7bddb4d82de7e0adb3eab49e6aa81b4de7
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 61b38c073d5e1e96a3d45271b257aef27d0d13da2bea5347692ae579475cd95e
-F src/sqliteInt.h 0eb4c251a6df26fb97fcd0c285c5dd442f90f0d0305c14f2a9d0cfc006a0e1da
+F src/sqliteInt.h e484ffb8ce2182ecd745b2e0af0caa12996e848b0f91748c742d1d135d31770c
 F src/sqliteLimit.h d7323ffea5208c6af2734574bae933ca8ed2ab728083caa117c9738581a31657
 F src/status.c 4b8bc2a6905163a38b739854a35b826c737333fab5b1f8e03fa7eb9a4799c4c1
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -604,9 +604,9 @@ F src/test_windirent.h 90dfbe95442c9762357fe128dc7ae3dc199d006de93eb33ba3972e0a9
 F src/test_window.c cdae419fdcea5bad6dcd9368c685abdad6deb59e9fc8b84b153de513d394ba3f
 F src/test_wsd.c 41cadfd9d97fe8e3e4e44f61a4a8ccd6f7ca8fe9
 F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
-F src/tokenize.c 01dba3023659dc6f6b1e054c14b35a0074bd35de10466b99454d33278191d97f
+F src/tokenize.c c64c49d7c2ec4490c2fef1f24350167ba16b03b0c6cee58ad1a1d70a4325d4e9
 F src/treeview.c 4b92992176fb2caefbe06ba5bd06e0e0ebcde3d5564758da672631f17aa51cda
-F src/trigger.c 515e79206d40d1d4149129318582e79a6e9db590a7b74e226fdb5b2a6c7e1b10
+F src/trigger.c 29680c54c1aa088fa1b4d50137d75669a40d5ef814394e321fab1e547868e3d3
 F src/update.c 9f126204a6acb96bbe47391ae48e0fc579105d8e76a6d9c4fab3271367476580
 F src/upsert.c df8f1727d62b5987c4fd302cd4d7c0c84ae57cd65683c5a34a740dfe24039235
 F src/utf.c ee39565f0843775cc2c81135751ddd93eceb91a673ea2c57f61c76f288b041a0
@@ -1895,7 +1895,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 5204c2c4a7b73a64764b0d2d1d7c53709bb64e0d2685a829c7bf31af13bab5e7
+P 49dfce469e6a17111b349e53578479daf783064200bf0eec5bf8a91d3553b19f
-R 08e016b91a617b99baf0add20ffab4d1
+R f1889156a8e996b56aa3e8cdd75a199d
 U drh
-Z 8b24dd36b9adf4430f5fd36c021c9d5f
+Z 2f77ed20cd8529f3498738d09cff4442

manifest.uuid

@@ -1 +1 @@
-49dfce469e6a17111b349e53578479daf783064200bf0eec5bf8a91d3553b19f
+affa2b7b316941b8a6c4d0d1ff212c81a593faf1d05d129e14d2b70d73a25c59

src/insert.c

@@ -371,6 +371,7 @@ static int autoIncBegin(
     if( pInfo==0 ){
       pInfo = sqlite3DbMallocRawNN(pParse->db, sizeof(*pInfo));
       if( pInfo==0 ) return 0;
+      sqlite3ParserAddCleanup(pToplevel, sqlite3DbFreeNN, pInfo);
       pInfo->pNext = pToplevel->pAinc;
       pToplevel->pAinc = pInfo;
       pInfo->pTab = pTab;

src/prepare.c

@@ -570,8 +570,16 @@ void sqlite3ParserReset(Parse *pParse){
     agginfoFree(db, pThis);
     pThis = pNext;
   }
+  while( pParse->pCleanup ){
+    ParseCleanup *pThis = pParse->pCleanup;
+    pParse->pCleanup = pThis->pNext;
+    pThis->xCleanup(db, pThis->pPtr);
+    sqlite3DbFree(db, pThis);
+  }
   sqlite3DbFree(db, pParse->aLabel);
-  sqlite3ExprListDelete(db, pParse->pConstExpr);
+  if( pParse->pConstExpr ){
+    sqlite3ExprListDelete(db, pParse->pConstExpr);
+  }
   if( db ){
     assert( db->lookaside.bDisable >= pParse->disableLookaside );
     db->lookaside.bDisable -= pParse->disableLookaside;
@@ -580,6 +588,34 @@ void sqlite3ParserReset(Parse *pParse){
   pParse->disableLookaside = 0;
 }
 
+/*
+** Add a new cleanup operation to a Parser.  The cleanup should happen when
+** the parser object is destroyed.
+**
+** Use this mechanism for uncommon cleanups.  There is a higher setup
+** cost, so this should not be used for common cleanups.  But for less
+** common cleanups, we save a single NULL-pointer comparison in
+** sqlite3ParserReset(), which makes a surprising difference in total
+** performance.
+**
+** If a memory allocation error occurs, then the cleanup happens immediately.
+*/
+void sqlite3ParserAddCleanup(
+  Parse *pParse,
+  void (*xCleanup)(sqlite3*,void*),
+  void *pPtr
+){
+  ParseCleanup *pCleanup = sqlite3DbMallocRaw(pParse->db, sizeof(*pCleanup));
+  if( pCleanup ){
+    pCleanup->pNext = pParse->pCleanup;
+    pParse->pCleanup = pCleanup;
+    pCleanup->pPtr = pPtr;
+    pCleanup->xCleanup = xCleanup;
+  }else{
+    xCleanup(pParse->db, pPtr);
+  }
+}
+
 /*
 ** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
 */

src/select.c

@@ -4140,8 +4140,9 @@ static int flattenSubquery(
     Table *pTabToDel = pSubitem->pTab;
     if( pTabToDel->nTabRef==1 ){
       Parse *pToplevel = sqlite3ParseToplevel(pParse);
-      pTabToDel->pNextZombie = pToplevel->pZombieTab;
+      sqlite3ParserAddCleanup(pToplevel, 
-      pToplevel->pZombieTab = pTabToDel;
+         (void(*)(sqlite3*,void*))sqlite3DeleteTable,
+         pTabToDel);
     }else{
       pTabToDel->nTabRef--;
     }
@@ -4856,12 +4857,15 @@ static struct Cte *searchWith(
 ** statement with which it is associated.
 */
 void sqlite3WithPush(Parse *pParse, With *pWith, u8 bFree){
-  assert( bFree==0 || (pParse->pWith==0 && pParse->pWithToFree==0) );
   if( pWith ){
     assert( pParse->pWith!=pWith );
     pWith->pOuter = pParse->pWith;
     pParse->pWith = pWith;
-    if( bFree ) pParse->pWithToFree = pWith;
+    if( bFree ){
+      sqlite3ParserAddCleanup(pParse, 
+         (void(*)(sqlite3*,void*))sqlite3WithDelete,
+         pWith);
+    }
   }
 }
 

src/sqliteInt.h

@@ -1154,6 +1154,7 @@ typedef struct LookasideSlot LookasideSlot;
 typedef struct Module Module;
 typedef struct NameContext NameContext;
 typedef struct Parse Parse;
+typedef struct ParseCleanup ParseCleanup;
 typedef struct PreUpdate PreUpdate;
 typedef struct PrintfArguments PrintfArguments;
 typedef struct RenameToken RenameToken;
@@ -2186,7 +2187,6 @@ struct Table {
 #endif
   Trigger *pTrigger;   /* List of triggers stored in pSchema */
   Schema *pSchema;     /* Schema that contains this table */
-  Table *pNextZombie;  /* Next on the Parse.pZombieTab list */
 };
 
 /*
@@ -3348,6 +3348,17 @@ struct TriggerPrg {
 # define DbMaskNonZero(M)   (M)!=0
 #endif
 
+/*
+** An instance of the ParseCleanup object specifies an operation that
+** should be performed after parsing to deallocation resources obtained
+** during the parse and which are no longer needed.
+*/
+struct ParseCleanup {
+  ParseCleanup *pNext;               /* Next cleanup task */
+  void *pPtr;                        /* Pointer to object to deallocate */
+  void (*xCleanup)(sqlite3*,void*);  /* Deallocation routine */
+};
+
 /*
 ** An SQL parser context.  A copy of this structure is passed through
 ** the parser and down into all the parser action routine in order to
@@ -3457,10 +3468,9 @@ struct Parse {
   Token sArg;               /* Complete text of a module argument */
   Table **apVtabLock;       /* Pointer to virtual tables needing locking */
 #endif
-  Table *pZombieTab;        /* List of Table objects to delete after code gen */
   TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
   With *pWith;              /* Current WITH clause, or NULL */
-  With *pWithToFree;        /* Free this WITH object at the end of the parse */
+  ParseCleanup *pCleanup;   /* List of cleanup operations to run after parse */
 #ifndef SQLITE_OMIT_ALTERTABLE
   RenameToken *pRename;     /* Tokens subject to renaming by ALTER TABLE */
 #endif
@@ -4827,6 +4837,7 @@ sqlite3_int64 sqlite3StmtCurrentTime(sqlite3_context*);
 int sqlite3VdbeParameterIndex(Vdbe*, const char*, int);
 int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
 void sqlite3ParserReset(Parse*);
+void sqlite3ParserAddCleanup(Parse*,void(*)(sqlite3*,void*),void*);
 #ifdef SQLITE_ENABLE_NORMALIZE
 char *sqlite3Normalize(Vdbe*, const char*);
 #endif

src/tokenize.c

@@ -713,19 +713,7 @@ int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzErrMsg){
   if( !IN_RENAME_OBJECT ){
     sqlite3DeleteTrigger(db, pParse->pNewTrigger);
   }
-
-  if( pParse->pWithToFree ) sqlite3WithDelete(db, pParse->pWithToFree);
   sqlite3DbFree(db, pParse->pVList);
-  while( pParse->pAinc ){
-    AutoincInfo *p = pParse->pAinc;
-    pParse->pAinc = p->pNext;
-    sqlite3DbFreeNN(db, p);
-  }
-  while( pParse->pZombieTab ){
-    Table *p = pParse->pZombieTab;
-    pParse->pZombieTab = p->pNextZombie;
-    sqlite3DeleteTable(db, p);
-  }
   db->pParse = pParse->pParentParse;
   pParse->pParentParse = 0;
   assert( nErr==0 || pParse->rc!=SQLITE_OK );

src/trigger.c

@@ -1000,7 +1000,6 @@ static TriggerPrg *codeRowTrigger(
     sqlite3VdbeDelete(v);
   }
 
-  assert( !pSubParse->pAinc       && !pSubParse->pZombieTab );
   assert( !pSubParse->pTriggerPrg && !pSubParse->nMaxArg );
   sqlite3ParserReset(pSubParse);
   sqlite3StackFree(db, pSubParse);