In the Mem object, stop requiring that Mem.xDel be NULL when the MEM_Dyn

bit is clear.  Also reduce the amount of initialization of Mem objects.
All for a small size reduction and performance increase.

FossilOrigin-Name: fdddb477c89dabb9f7bf2d5ccb32534868df3a03

manifest

@@ -1,5 +1,5 @@
-C Improved\sinterface\sto\sthe\sMem\sobject\shandling.\s\sSmall\ssize\sreduction\sand\nperformance\sincrease.
-D 2014-09-17T14:52:46.727
+C In\sthe\sMem\sobject,\sstop\srequiring\sthat\sMem.xDel\sbe\sNULL\swhen\sthe\sMEM_Dyn\nbit\sis\sclear.\s\sAlso\sreduce\sthe\samount\sof\sinitialization\sof\sMem\sobjects.\nAll\sfor\sa\ssmall\ssize\sreduction\sand\sperformance\sincrease.
+D 2014-09-17T16:41:15.094
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in cf57f673d77606ab0f2d9627ca52a9ba1464146a
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -288,13 +288,13 @@ F src/update.c 729f6f18fc27740591d085e1172cebe311144bf0
 F src/utf.c 8f634b93d41c089029dd503161a7d3e685d59a9c
 F src/util.c 4006c01772bd8d8ac4306d523bbcee41d3e392d8
 F src/vacuum.c 59f03f92bcff57faa6a8ca256eb29ccddfb0614a
-F src/vdbe.c d39487782c0c6a2448bd1b351eba6a2dce101343
+F src/vdbe.c d3c548ad4ea6a5549d2d0b502070e0523023ff97
 F src/vdbe.h 09f5b4e3719fa454f252322b1cdab5cf1f361327
-F src/vdbeInt.h 9d398055c873980b61ce0f7bf82140a8e4e2ccbc
+F src/vdbeInt.h f90b0de6153f50de630a5a113537efb47083812f
 F src/vdbeapi.c c6e63f913bcb12977731a8b12e7e5c5762981527
-F src/vdbeaux.c 211ad29d51e01c44a0db1ab69b74c11c8de1cccf
+F src/vdbeaux.c 9ac63bc59d2783df77e591e4c4fa8c1153a07eab
 F src/vdbeblob.c 848238dc73e93e48432991bb5651bf87d865eca4
-F src/vdbemem.c cf552a404f0e73a48bd266699aa27f0df26b096b
+F src/vdbemem.c 8b5e1083fed2da94e315858a7edf5604a5b91804
 F src/vdbesort.c 09efa5e5098d1a159cd21f588eb118e4fe87cfde
 F src/vdbetrace.c 16d39c1ef7d1f4a3a7464bea3b7b4bdd7849c415
 F src/vtab.c 019dbfd0406a7447c990e1f7bd1dfcdb8895697f
@@ -1198,7 +1198,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 2598aedc5dd2bac67e2e518a31f2803e469c2ba6
-R f63e98cc1bcae44946c79c20cdee7610
+P 4e437844322cc20eef92928b53fa6b37eded586e
+R 8244691fd19236cfb5e445e4012669fa
 U drh
-Z 1559702e8c6b5218f324b4f43d7dc2c7
+Z ef23a1637c5e3046b6cead80453b022e

manifest.uuid

@@ -1 +1 @@
-4e437844322cc20eef92928b53fa6b37eded586e
+fdddb477c89dabb9f7bf2d5ccb32534868df3a03

src/vdbe.c

@@ -1174,7 +1174,6 @@ case OP_Move: {
     }
 #endif
     pIn1->flags = MEM_Undefined;
-    pIn1->xDel = 0;
     pIn1->zMalloc = zMalloc;
     REGISTER_TRACE(p2++, pOut);
     pIn1++;
@@ -2645,7 +2644,6 @@ case OP_MakeRecord: {
   assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
   pOut->n = (int)nByte;
   pOut->flags = MEM_Blob;
-  pOut->xDel = 0;
   if( nZero ){
     pOut->u.nZero = nZero;
     pOut->flags |= MEM_Zero;
@@ -4755,7 +4753,7 @@ case OP_IdxRowid: {              /* out2-prerelease */
   assert( pC->isTable==0 );
   if( !pC->nullRow ){
     rowid = 0;  /* Not needed.  Only used to silence a warning. */
-    rc = sqlite3VdbeIdxRowid(pCrsr, &rowid);
+    rc = sqlite3VdbeIdxRowid(db, pCrsr, &rowid);
     if( rc!=SQLITE_OK ){
       goto abort_due_to_error;
     }
@@ -4839,7 +4837,7 @@ case OP_IdxGE:  {       /* jump */
   { int i; for(i=0; i<r.nField; i++) assert( memIsValid(&r.aMem[i]) ); }
 #endif
   res = 0;  /* Not needed.  Only used to silence a warning. */
-  rc = sqlite3VdbeIdxKeyCompare(pC, &r, &res);
+  rc = sqlite3VdbeIdxKeyCompare(db, pC, &r, &res);
   assert( (OP_IdxLE&1)==(OP_IdxLT&1) && (OP_IdxGE&1)==(OP_IdxGT&1) );
   if( (pOp->opcode&1)==(OP_IdxLT&1) ){
     assert( pOp->opcode==OP_IdxLE || pOp->opcode==OP_IdxLT );
@@ -5609,11 +5607,7 @@ case OP_AggStep: {
   assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
   ctx.pMem = pMem = &aMem[pOp->p3];
   pMem->n++;
-  t.flags = MEM_Null;
-  t.z = 0;
-  t.zMalloc = 0;
-  t.xDel = 0;
-  t.db = db;
+  sqlite3VdbeMemInit(&t, db, MEM_Null);
   ctx.pOut = &t;
   ctx.isError = 0;
   ctx.pColl = 0;

src/vdbeInt.h

@@ -176,7 +176,7 @@ struct Mem {
   char *zMalloc;      /* Dynamic buffer allocated by sqlite3_malloc() */
   /* ShallowCopy only needs to copy the information above */
   sqlite3 *db;        /* The associated database connection */
-  void (*xDel)(void*);/* If not null, call this function to delete Mem.z */
+  void (*xDel)(void*);/* Destructor for Mem.z - only valid if MEM_Dyn */
 #ifdef SQLITE_DEBUG
   Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
   void *pFiller;      /* So that sizeof(Mem) is a multiple of 8 */
@@ -397,8 +397,8 @@ u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
 void sqlite3VdbeDeleteAuxData(Vdbe*, int, int);
 
 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
-int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*);
-int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
+int sqlite3VdbeIdxKeyCompare(sqlite3*,VdbeCursor*,UnpackedRecord*,int*);
+int sqlite3VdbeIdxRowid(sqlite3*, BtCursor*, i64*);
 int sqlite3VdbeExec(Vdbe*);
 int sqlite3VdbeList(Vdbe*);
 int sqlite3VdbeHalt(Vdbe*);
@@ -415,6 +415,7 @@ void sqlite3VdbeMemSetInt64(Mem*, i64);
 #else
   void sqlite3VdbeMemSetDouble(Mem*, double);
 #endif
+void sqlite3VdbeMemInit(Mem*,sqlite3*,u16);
 void sqlite3VdbeMemSetNull(Mem*);
 void sqlite3VdbeMemSetZeroBlob(Mem*,int);
 void sqlite3VdbeMemSetRowSet(Mem*);

src/vdbeaux.c

@@ -3085,7 +3085,6 @@ u32 sqlite3VdbeSerialGet(
       static const u16 aFlag[] = { MEM_Blob|MEM_Ephem, MEM_Str|MEM_Ephem };
       pMem->z = (char *)buf;
       pMem->n = (serial_type-12)/2;
-      pMem->xDel = 0;
       pMem->flags = aFlag[serial_type&1];
       return pMem->n;
     }
@@ -3306,7 +3305,6 @@ static int vdbeCompareMemString(
     c1.db = c2.db = pMem1->db;
     c1.flags = c2.flags = 0;
     c1.zMalloc = c2.zMalloc = 0;
-    c1.xDel = c2.xDel = 0;
     sqlite3VdbeMemShallowCopy(&c1, pMem1, MEM_Ephem);
     sqlite3VdbeMemShallowCopy(&c2, pMem2, MEM_Ephem);
     v1 = sqlite3ValueText((sqlite3_value*)&c1, pColl->enc);
@@ -3877,7 +3875,7 @@ RecordCompare sqlite3VdbeFindCompare(UnpackedRecord *p){
 ** pCur might be pointing to text obtained from a corrupt database file.
 ** So the content cannot be trusted.  Do appropriate checks on the content.
 */
-int sqlite3VdbeIdxRowid(BtCursor *pCur, i64 *rowid){
+int sqlite3VdbeIdxRowid(sqlite3 *db, BtCursor *pCur, i64 *rowid){
   i64 nCellKey = 0;
   int rc;
   u32 szHdr;        /* Size of the header */
@@ -3896,7 +3894,7 @@ int sqlite3VdbeIdxRowid(BtCursor *pCur, i64 *rowid){
   assert( (nCellKey & SQLITE_MAX_U32)==(u64)nCellKey );
 
   /* Read in the complete content of the index entry */
-  memset(&m, 0, sizeof(m));
+  sqlite3VdbeMemInit(&m, db, 0);
   rc = sqlite3VdbeMemFromBtree(pCur, 0, (u32)nCellKey, 1, &m);
   if( rc ){
     return rc;
@@ -3956,6 +3954,7 @@ idx_rowid_corruption:
 ** of the keys prior to the final rowid, not the entire key.
 */
 int sqlite3VdbeIdxKeyCompare(
+  sqlite3 *db,                     /* Database connection */
   VdbeCursor *pC,                  /* The cursor to compare against */
   UnpackedRecord *pUnpacked,       /* Unpacked version of key */
   int *res                         /* Write the comparison result here */
@@ -3974,7 +3973,7 @@ int sqlite3VdbeIdxKeyCompare(
     *res = 0;
     return SQLITE_CORRUPT_BKPT;
   }
-  memset(&m, 0, sizeof(m));
+  sqlite3VdbeMemInit(&m, db, 0);
   rc = sqlite3VdbeMemFromBtree(pC->pCursor, 0, (u32)nCellKey, 1, &m);
   if( rc ){
     return rc;

src/vdbemem.c

@@ -26,11 +26,10 @@
 ** this:    assert( sqlite3VdbeCheckMemInvariants(pMem) );
 */
 int sqlite3VdbeCheckMemInvariants(Mem *p){
-  /* The MEM_Dyn bit is set if and only if Mem.xDel is a non-NULL destructor
-  ** function for Mem.z 
+  /* If MEM_Dyn is set then Mem.xDel!=0.  
+  ** Mem.xDel is might not be initialized if MEM_Dyn is clear.
   */
   assert( (p->flags & MEM_Dyn)==0 || p->xDel!=0 );
-  assert( (p->flags & MEM_Dyn)!=0 || p->xDel==0 );
 
   /* If p holds a string or blob, the Mem.z must point to exactly
   ** one of the following:
@@ -136,7 +135,6 @@ int sqlite3VdbeMemGrow(Mem *pMem, int n, int bPreserve){
 
   pMem->z = pMem->zMalloc;
   pMem->flags &= ~(MEM_Dyn|MEM_Ephem|MEM_Static);
-  pMem->xDel = 0;
   return SQLITE_OK;
 }
 
@@ -299,7 +297,7 @@ int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
     ctx.pMem = pMem;
     ctx.pFunc = pFunc;
     pFunc->xFinalize(&ctx); /* IMP: R-24505-23230 */
-    assert( 0==(pMem->flags&MEM_Dyn) && !pMem->xDel );
+    assert( (pMem->flags & MEM_Dyn)==0 );
     sqlite3DbFree(pMem->db, pMem->zMalloc);
     memcpy(pMem, &t, sizeof(t));
     rc = ctx.isError;
@@ -328,7 +326,6 @@ static SQLITE_NOINLINE void vdbeMemClearExternAndSetNull(Mem *p){
     assert( (p->flags&MEM_RowSet)==0 );
     assert( p->xDel!=SQLITE_DYNAMIC && p->xDel!=0 );
     p->xDel((void *)p->z);
-    p->xDel = 0;
   }else if( p->flags&MEM_RowSet ){
     sqlite3RowSetClear(p->u.pRowSet);
   }else if( p->flags&MEM_Frame ){
@@ -373,7 +370,6 @@ void sqlite3VdbeMemRelease(Mem *p){
   if( VdbeMemDynamic(p) || p->zMalloc ){
     vdbeMemClear(p);
   }
-  assert( p->xDel==0 );
 }
 
 /*
@@ -585,6 +581,18 @@ void sqlite3VdbeMemCast(Mem *pMem, u8 aff, u8 encoding){
   }
 }
 
+/*
+** Initialize bulk memory to be a consistent Mem object.
+**
+** The minimum amount of initialization feasible is performed.
+*/
+void sqlite3VdbeMemInit(Mem *pMem, sqlite3 *db, u16 flags){
+  assert( (flags & ~MEM_TypeMask)==0 );
+  pMem->flags = flags;
+  pMem->db = db;
+  pMem->zMalloc = 0;
+}
+
 
 /*
 ** Delete any previous value and set the value stored in *pMem to NULL.
@@ -736,7 +744,6 @@ void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
   assert( pTo->db==pFrom->db );
   if( VdbeMemDynamic(pTo) ) vdbeMemClearExternAndSetNull(pTo);
   memcpy(pTo, pFrom, MEMCELLSIZE);
-  assert( pTo->xDel==0 );
   if( (pFrom->flags&MEM_Static)==0 ){
     pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
     assert( srcType==MEM_Ephem || srcType==MEM_Static );
@@ -756,8 +763,6 @@ int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
   if( VdbeMemDynamic(pTo) ) vdbeMemClearExternAndSetNull(pTo);
   memcpy(pTo, pFrom, MEMCELLSIZE);
   pTo->flags &= ~MEM_Dyn;
-  assert( pTo->xDel==0 );
-
   if( pTo->flags&(MEM_Str|MEM_Blob) ){
     if( 0==(pFrom->flags&MEM_Static) ){
       pTo->flags |= MEM_Ephem;
@@ -782,7 +787,6 @@ void sqlite3VdbeMemMove(Mem *pTo, Mem *pFrom){
   sqlite3VdbeMemRelease(pTo);
   memcpy(pTo, pFrom, sizeof(Mem));
   pFrom->flags = MEM_Null;
-  pFrom->xDel = 0;
   pFrom->zMalloc = 0;
 }
 
@@ -857,7 +861,6 @@ int sqlite3VdbeMemSetStr(
   }else if( xDel==SQLITE_DYNAMIC ){
     sqlite3VdbeMemRelease(pMem);
     pMem->zMalloc = pMem->z = (char *)z;
-    pMem->xDel = 0;
   }else{
     sqlite3VdbeMemRelease(pMem);
     pMem->z = (char *)z;
@@ -910,7 +913,7 @@ int sqlite3VdbeMemFromBtree(
   int rc = SQLITE_OK; /* Return code */
 
   assert( sqlite3BtreeCursorIsValid(pCur) );
-  assert( pMem->xDel==0 );
+  assert( !VdbeMemDynamic(pMem) );
 
   /* Note: the calls to BtreeKeyFetch() and DataFetch() below assert() 
   ** that both the BtShared and database handle mutexes are held. */
@@ -923,7 +926,6 @@ int sqlite3VdbeMemFromBtree(
   assert( zData!=0 );
 
   if( offset+amt<=available ){
-    sqlite3VdbeMemRelease(pMem);
     pMem->z = &zData[offset];
     pMem->flags = MEM_Blob|MEM_Ephem;
     pMem->n = (int)amt;