From: drh <drh@noemail.net>
Date: Sat, 19 Mar 2016 23:32:58 +0000 (+0000)
Subject: Change the Vdbe.aMem array so that it is zero-based instead of one-based.
X-Git-Tag: version-3.12.0~31^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9f6168b6a3bbd7656fd2428049144e403e9cb037;p=thirdparty%2Fsqlite.git

Change the Vdbe.aMem array so that it is zero-based instead of one-based.

FossilOrigin-Name: e07b0c47eb5a39623f5fe0e66b939bba0906691c
---

diff --git a/manifest b/manifest
index 847bc79890..dc84917b98 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sexclusive.test\sso\sthat\sit\sworks\swith\s-DSQLITE_TEMP_STORE=3.
-D 2016-03-19T18:11:59.750
+C Change\sthe\sVdbe.aMem\sarray\sso\sthat\sit\sis\szero-based\sinstead\sof\sone-based.
+D 2016-03-19T23:32:59.000
 F Makefile.in f53429fb2f313c099283659d0df6f20f932c861f
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc df0bf9ff7f8b3f4dd9fb4cc43f92fe58f6ec5c66
@@ -417,13 +417,13 @@ F src/update.c 56b3db7edff0110360a12b76af97c39ebe3ea8b8
 F src/utf.c 699001c79f28e48e9bcdf8a463da029ea660540c
 F src/util.c 34ef7be420f82415ec48131404995ddb6ee7502f
 F src/vacuum.c feb1eabb20987983d9350cad98299b21fa811f52
-F src/vdbe.c 8cf45bb8da77d39f55d108e759d15a57acd0255c
+F src/vdbe.c 90d18d0a91284092a099e9a048982df38920190c
 F src/vdbe.h 6f44193e7be52fd5f7c308175a936555b1e6b101
 F src/vdbeInt.h f88d3115e9bde33b01d81f0dd26d8dd51f995991
 F src/vdbeapi.c 95b1f8e527240a18a9aea41a655b013bf07a7009
-F src/vdbeaux.c a930f913d40e4ca6f6caaef6a7b5906a369fa2b1
+F src/vdbeaux.c 4a38b9f9dab7350f670b9efff25f605933f81963
 F src/vdbeblob.c 3b570b730109e8f653d9d2081649f6e7015113db
-F src/vdbemem.c 9b0cb32cc267ef026515f15a3594d5ff91fe4dfc
+F src/vdbemem.c fe76c1f866de362d9b8332e59d74aa44f6560d69
 F src/vdbesort.c 307460bfa4de4d1c3901fcd42089159131e34062
 F src/vdbetrace.c f75c5455d8cf389ef86a8bfdfd3177e0e3692484
 F src/vtab.c fd69fd398e23e57ea4ea377d8a44b6998fc569c7
@@ -1457,7 +1457,10 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P f095341471aa822e6d556cb65512ec081c3918da
-R eda7e2fd58d6241fa97b2fe69addd6c1
-U dan
-Z fdac7ca02eef2361aeb61c0eeeaed018
+P d7852c639683a1d305a1e731df3cccafa64b594b
+R 4a4c5282463bb7b6f1f36414c3f19a6f
+T *branch * zero-base-aMem
+T *sym-zero-base-aMem *
+T -sym-trunk *
+U drh
+Z 5ba539d03a989ddc8c4359f1a3ede74d
diff --git a/manifest.uuid b/manifest.uuid
index 378b71e1fc..24fae6a151 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-d7852c639683a1d305a1e731df3cccafa64b594b
\ No newline at end of file
+e07b0c47eb5a39623f5fe0e66b939bba0906691c
\ No newline at end of file
diff --git a/src/vdbe.c b/src/vdbe.c
index 6f4ac5713d..bdab41b6b6 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -192,11 +192,11 @@ static VdbeCursor *allocateCursor(
   **     be freed lazily via the sqlite3_release_memory() API. This
   **     minimizes the number of malloc calls made by the system.
   **
-  ** Memory cells for cursors are allocated at the top of the address
-  ** space. Memory cell (p->nMem) corresponds to cursor 0. Space for
-  ** cursor 1 is managed by memory cell (p->nMem-1), etc.
+  ** Memory cell for cursor 0 is Mem[0]. The rest are allocated from
+  ** the top of the register space.  Cursor 1 is at Mem[p->nMem-1].
+  ** Cursor 2 is at Mem[p->nMem-2]. And so forth.
   */
-  Mem *pMem = &p->aMem[p->nMem-iCur];
+  Mem *pMem = iCur>0 ? &p->aMem[p->nMem-iCur] : p->aMem;
 
   int nByte;
   VdbeCursor *pCx = 0;
@@ -204,7 +204,7 @@ static VdbeCursor *allocateCursor(
       ROUND8(sizeof(VdbeCursor)) + 2*sizeof(u32)*nField + 
       (eCurType==CURTYPE_BTREE?sqlite3BtreeCursorSize():0);
 
-  assert( iCur<p->nCursor );
+  assert( iCur>=0 && iCur<p->nCursor );
   if( p->apCsr[iCur] ){
     sqlite3VdbeFreeCursor(p, p->apCsr[iCur]);
     p->apCsr[iCur] = 0;
@@ -529,7 +529,7 @@ static SQLITE_NOINLINE Mem *out2PrereleaseWithClear(Mem *pOut){
 static Mem *out2Prerelease(Vdbe *p, VdbeOp *pOp){
   Mem *pOut;
   assert( pOp->p2>0 );
-  assert( pOp->p2<=(p->nMem-p->nCursor) );
+  assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
   pOut = &p->aMem[pOp->p2];
   memAboutToChange(p, pOut);
   if( VdbeMemDynamic(pOut) ){
@@ -667,33 +667,33 @@ int sqlite3VdbeExec(
     assert( pOp->opflags==sqlite3OpcodeProperty[pOp->opcode] );
     if( (pOp->opflags & OPFLG_IN1)!=0 ){
       assert( pOp->p1>0 );
-      assert( pOp->p1<=(p->nMem-p->nCursor) );
+      assert( pOp->p1<=(p->nMem+1 - p->nCursor) );
       assert( memIsValid(&aMem[pOp->p1]) );
       assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p1]) );
       REGISTER_TRACE(pOp->p1, &aMem[pOp->p1]);
     }
     if( (pOp->opflags & OPFLG_IN2)!=0 ){
       assert( pOp->p2>0 );
-      assert( pOp->p2<=(p->nMem-p->nCursor) );
+      assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
       assert( memIsValid(&aMem[pOp->p2]) );
       assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p2]) );
       REGISTER_TRACE(pOp->p2, &aMem[pOp->p2]);
     }
     if( (pOp->opflags & OPFLG_IN3)!=0 ){
       assert( pOp->p3>0 );
-      assert( pOp->p3<=(p->nMem-p->nCursor) );
+      assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
       assert( memIsValid(&aMem[pOp->p3]) );
       assert( sqlite3VdbeCheckMemInvariants(&aMem[pOp->p3]) );
       REGISTER_TRACE(pOp->p3, &aMem[pOp->p3]);
     }
     if( (pOp->opflags & OPFLG_OUT2)!=0 ){
       assert( pOp->p2>0 );
-      assert( pOp->p2<=(p->nMem-p->nCursor) );
+      assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
       memAboutToChange(p, &aMem[pOp->p2]);
     }
     if( (pOp->opflags & OPFLG_OUT3)!=0 ){
       assert( pOp->p3>0 );
-      assert( pOp->p3<=(p->nMem-p->nCursor) );
+      assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
       memAboutToChange(p, &aMem[pOp->p3]);
     }
 #endif
@@ -792,7 +792,7 @@ check_for_interrupt:
 ** and then jump to address P2.
 */
 case OP_Gosub: {            /* jump */
-  assert( pOp->p1>0 && pOp->p1<=(p->nMem-p->nCursor) );
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
   pIn1 = &aMem[pOp->p1];
   assert( VdbeMemDynamic(pIn1)==0 );
   memAboutToChange(p, pIn1);
@@ -832,7 +832,7 @@ case OP_Return: {           /* in1 */
 ** See also: EndCoroutine
 */
 case OP_InitCoroutine: {     /* jump */
-  assert( pOp->p1>0 &&  pOp->p1<=(p->nMem-p->nCursor) );
+  assert( pOp->p1>0 &&  pOp->p1<=(p->nMem+1 - p->nCursor) );
   assert( pOp->p2>=0 && pOp->p2<p->nOp );
   assert( pOp->p3>=0 && pOp->p3<p->nOp );
   pOut = &aMem[pOp->p1];
@@ -1101,7 +1101,7 @@ case OP_String: {          /* out2 */
 #ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
   if( pOp->p5 ){
     assert( pOp->p3>0 );
-    assert( pOp->p3<=(p->nMem-p->nCursor) );
+    assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
     pIn3 = &aMem[pOp->p3];
     assert( pIn3->flags & MEM_Int );
     if( pIn3->u.i ) pOut->flags = MEM_Blob|MEM_Static|MEM_Term;
@@ -1127,7 +1127,7 @@ case OP_Null: {           /* out2 */
   u16 nullFlag;
   pOut = out2Prerelease(p, pOp);
   cnt = pOp->p3-pOp->p2;
-  assert( pOp->p3<=(p->nMem-p->nCursor) );
+  assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
   pOut->flags = nullFlag = pOp->p1 ? (MEM_Null|MEM_Cleared) : MEM_Null;
   while( cnt>0 ){
     pOut++;
@@ -1148,7 +1148,7 @@ case OP_Null: {           /* out2 */
 ** previously copied using OP_SCopy, the copies will continue to be valid.
 */
 case OP_SoftNull: {
-  assert( pOp->p1>0 && pOp->p1<=(p->nMem-p->nCursor) );
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
   pOut = &aMem[pOp->p1];
   pOut->flags = (pOut->flags|MEM_Null)&~MEM_Undefined;
   break;
@@ -1215,8 +1215,8 @@ case OP_Move: {
   pIn1 = &aMem[p1];
   pOut = &aMem[p2];
   do{
-    assert( pOut<=&aMem[(p->nMem-p->nCursor)] );
-    assert( pIn1<=&aMem[(p->nMem-p->nCursor)] );
+    assert( pOut<=&aMem[(p->nMem+1 - p->nCursor)] );
+    assert( pIn1<=&aMem[(p->nMem+1 - p->nCursor)] );
     assert( memIsValid(pIn1) );
     memAboutToChange(p, pOut);
     sqlite3VdbeMemMove(pOut, pIn1);
@@ -1316,7 +1316,7 @@ case OP_ResultRow: {
   int i;
   assert( p->nResColumn==pOp->p2 );
   assert( pOp->p1>0 );
-  assert( pOp->p1+pOp->p2<=(p->nMem-p->nCursor)+1 );
+  assert( pOp->p1+pOp->p2<=(p->nMem+1 - p->nCursor)+1 );
 
 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
   /* Run the progress counter just before returning.
@@ -1628,8 +1628,8 @@ case OP_Function0: {
 
   assert( pOp->p4type==P4_FUNCDEF );
   n = pOp->p5;
-  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
-  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem-p->nCursor)+1) );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem+1 - p->nCursor)+1) );
   assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
   pCtx = sqlite3DbMallocRawNN(db, sizeof(*pCtx) + (n-1)*sizeof(sqlite3_value*));
   if( pCtx==0 ) goto no_mem;
@@ -2129,11 +2129,11 @@ case OP_Compare: {
   if( aPermute ){
     int k, mx = 0;
     for(k=0; k<n; k++) if( aPermute[k]>mx ) mx = aPermute[k];
-    assert( p1>0 && p1+mx<=(p->nMem-p->nCursor)+1 );
-    assert( p2>0 && p2+mx<=(p->nMem-p->nCursor)+1 );
+    assert( p1>0 && p1+mx<=(p->nMem+1 - p->nCursor)+1 );
+    assert( p2>0 && p2+mx<=(p->nMem+1 - p->nCursor)+1 );
   }else{
-    assert( p1>0 && p1+n<=(p->nMem-p->nCursor)+1 );
-    assert( p2>0 && p2+n<=(p->nMem-p->nCursor)+1 );
+    assert( p1>0 && p1+n<=(p->nMem+1 - p->nCursor)+1 );
+    assert( p2>0 && p2+n<=(p->nMem+1 - p->nCursor)+1 );
   }
 #endif /* SQLITE_DEBUG */
   for(i=0; i<n; i++){
@@ -2395,7 +2395,7 @@ case OP_Column: {
   /* If the cursor cache is stale, bring it up-to-date */
   rc = sqlite3VdbeCursorMoveto(&pC, &p2);
 
-  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
   pDest = &aMem[pOp->p3];
   memAboutToChange(p, pDest);
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
@@ -2638,7 +2638,7 @@ case OP_Affinity: {
   assert( zAffinity[pOp->p2]==0 );
   pIn1 = &aMem[pOp->p1];
   while( (cAff = *(zAffinity++))!=0 ){
-    assert( pIn1 <= &p->aMem[(p->nMem-p->nCursor)] );
+    assert( pIn1 <= &p->aMem[(p->nMem+1 - p->nCursor)] );
     assert( memIsValid(pIn1) );
     applyAffinity(pIn1, cAff, encoding);
     pIn1++;
@@ -2700,7 +2700,7 @@ case OP_MakeRecord: {
   nZero = 0;         /* Number of zero bytes at the end of the record */
   nField = pOp->p1;
   zAffinity = pOp->p4.z;
-  assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=(p->nMem-p->nCursor)+1 );
+  assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=(p->nMem+1 - p->nCursor)+1 );
   pData0 = &aMem[nField];
   nField = pOp->p2;
   pLast = &pData0[nField-1];
@@ -2790,7 +2790,7 @@ case OP_MakeRecord: {
   assert( i==nHdr );
   assert( j==nByte );
 
-  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
   pOut->n = (int)nByte;
   pOut->flags = MEM_Blob;
   if( nZero ){
@@ -3376,7 +3376,7 @@ case OP_OpenWrite:
   }
   if( pOp->p5 & OPFLAG_P2ISREG ){
     assert( p2>0 );
-    assert( p2<=(p->nMem-p->nCursor) );
+    assert( p2<=(p->nMem+1 - p->nCursor) );
     pIn2 = &aMem[p2];
     assert( memIsValid(pIn2) );
     assert( (pIn2->flags & MEM_Int)!=0 );
@@ -4171,7 +4171,7 @@ case OP_NewRowid: {           /* out2 */
         pMem = &pFrame->aMem[pOp->p3];
       }else{
         /* Assert that P3 is a valid memory cell. */
-        assert( pOp->p3<=(p->nMem-p->nCursor) );
+        assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
         pMem = &aMem[pOp->p3];
         memAboutToChange(p, pMem);
       }
@@ -4947,7 +4947,7 @@ case OP_IdxDelete: {
   UnpackedRecord r;
 
   assert( pOp->p3>0 );
-  assert( pOp->p2>0 && pOp->p2+pOp->p3<=(p->nMem-p->nCursor)+1 );
+  assert( pOp->p2>0 && pOp->p2+pOp->p3<=(p->nMem+1 - p->nCursor)+1 );
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   pC = p->apCsr[pOp->p1];
   assert( pC!=0 );
@@ -5453,7 +5453,7 @@ case OP_IntegrityCk: {
   aRoot = pOp->p4.ai;
   assert( nRoot>0 );
   assert( aRoot[nRoot]==0 );
-  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
   pnErr = &aMem[pOp->p3];
   assert( (pnErr->flags & MEM_Int)!=0 );
   assert( (pnErr->flags & (MEM_Str|MEM_Blob))==0 );
@@ -5643,6 +5643,7 @@ case OP_Program: {        /* jump */
     ** variable nMem (and later, VdbeFrame.nChildMem) to this value.
     */
     nMem = pProgram->nMem + pProgram->nCsr;
+    if( pProgram->nCsr==0 && nMem>0 ) nMem++;
     nByte = ROUND8(sizeof(VdbeFrame))
               + nMem * sizeof(Mem)
               + pProgram->nCsr * sizeof(VdbeCursor *)
@@ -5679,7 +5680,8 @@ case OP_Program: {        /* jump */
     }
   }else{
     pFrame = pRt->u.pFrame;
-    assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem );
+    assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem 
+        || (pProgram->nCsr==0 && pProgram->nMem+1==pFrame->nChildMem) );
     assert( pProgram->nCsr==pFrame->nChildCsr );
     assert( (int)(pOp - aOp)==pFrame->pc );
   }
@@ -5694,10 +5696,10 @@ case OP_Program: {        /* jump */
   p->pAuxData = 0;
   p->nChange = 0;
   p->pFrame = pFrame;
-  p->aMem = aMem = &VdbeFrameMem(pFrame)[-1];
+  p->aMem = aMem = VdbeFrameMem(pFrame);
   p->nMem = pFrame->nChildMem;
   p->nCursor = (u16)pFrame->nChildCsr;
-  p->apCsr = (VdbeCursor **)&aMem[p->nMem+1];
+  p->apCsr = (VdbeCursor **)&aMem[p->nMem];
   p->aOp = aOp = pProgram->aOp;
   p->nOp = pProgram->nOp;
   p->aOnceFlag = (u8 *)&p->apCsr[p->nCursor];
@@ -5943,8 +5945,8 @@ case OP_AggStep0: {
 
   assert( pOp->p4type==P4_FUNCDEF );
   n = pOp->p5;
-  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
-  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem-p->nCursor)+1) );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
+  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem+1 - p->nCursor)+1) );
   assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
   pCtx = sqlite3DbMallocRawNN(db, sizeof(*pCtx) + (n-1)*sizeof(sqlite3_value*));
   if( pCtx==0 ) goto no_mem;
@@ -6023,7 +6025,7 @@ case OP_AggStep: {
 */
 case OP_AggFinal: {
   Mem *pMem;
-  assert( pOp->p1>0 && pOp->p1<=(p->nMem-p->nCursor) );
+  assert( pOp->p1>0 && pOp->p1<=(p->nMem+1 - p->nCursor) );
   pMem = &aMem[pOp->p1];
   assert( (pMem->flags & ~(MEM_Null|MEM_Agg))==0 );
   rc = sqlite3VdbeMemFinalize(pMem, pOp->p4.pFunc);
@@ -6465,7 +6467,7 @@ case OP_VColumn: {
 
   VdbeCursor *pCur = p->apCsr[pOp->p1];
   assert( pCur->eCurType==CURTYPE_VTAB );
-  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
+  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
   pDest = &aMem[pOp->p3];
   memAboutToChange(p, pDest);
   if( pCur->nullRow ){
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index c71605cdd2..75307c258e 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -1801,7 +1801,7 @@ void sqlite3VdbeRewind(Vdbe *p){
   p->magic = VDBE_MAGIC_RUN;
 
 #ifdef SQLITE_DEBUG
-  for(i=1; i<p->nMem; i++){
+  for(i=0; i<p->nMem; i++){
     assert( p->aMem[i].db==p->db );
   }
 #endif
@@ -1866,16 +1866,18 @@ void sqlite3VdbeMakeReady(
   nOnce = pParse->nOnce;
   if( nOnce==0 ) nOnce = 1; /* Ensure at least one byte in p->aOnceFlag[] */
   
-  /* For each cursor required, also allocate a memory cell. Memory
-  ** cells (nMem+1-nCursor)..nMem, inclusive, will never be used by
+  /* For each cursor required, also allocate a memory cell.  Memory
+  ** cells 0 and (nMem-nCursor)..nMem-1 inclusive will never be used by
   ** the vdbe program. Instead they are used to allocate memory for
   ** VdbeCursor/BtCursor structures. The blob of memory associated with 
-  ** cursor 0 is stored in memory cell nMem. Memory cell (nMem-1)
-  ** stores the blob of memory associated with cursor 1, etc.
+  ** cursor 0 is stored in memory cell 0. Memory cell (nMem-1)
+  ** stores the blob of memory associated with cursor 1.  Memory cell
+  ** (nMem-iCur) is used for cursor iCur.
   **
   ** See also: allocateCursor().
   */
   nMem += nCursor;
+  if( nCursor==0 && nMem>0 ) nMem++;  /* Space for aMem[0] even if not used */
 
   /* Figure out how much reusable memory is available at the end of the
   ** opcode array.  This extra memory will be reallocated for other elements
@@ -1937,9 +1939,8 @@ void sqlite3VdbeMakeReady(
   pParse->nzVar =  0;
   pParse->azVar = 0;
   if( p->aMem ){
-    p->aMem--;                      /* aMem[] goes from 1..nMem */
-    p->nMem = nMem;                 /*       not from 0..nMem-1 */
-    for(n=1; n<=nMem; n++){
+    p->nMem = nMem;
+    for(n=0; n<nMem; n++){
       p->aMem[n].flags = MEM_Undefined;
       p->aMem[n].db = db;
     }
@@ -2049,7 +2050,7 @@ static void closeAllCursors(Vdbe *p){
   assert( p->nFrame==0 );
   closeCursorsInFrame(p);
   if( p->aMem ){
-    releaseMemArray(&p->aMem[1], p->nMem);
+    releaseMemArray(p->aMem, p->nMem);
   }
   while( p->pDelFrame ){
     VdbeFrame *pDel = p->pDelFrame;
@@ -2074,7 +2075,7 @@ static void Cleanup(Vdbe *p){
   int i;
   if( p->apCsr ) for(i=0; i<p->nCursor; i++) assert( p->apCsr[i]==0 );
   if( p->aMem ){
-    for(i=1; i<=p->nMem; i++) assert( p->aMem[i].flags==MEM_Undefined );
+    for(i=0; i<p->nMem; i++) assert( p->aMem[i].flags==MEM_Undefined );
   }
 #endif
 
diff --git a/src/vdbemem.c b/src/vdbemem.c
index b5139fe32e..2c03baf562 100644
--- a/src/vdbemem.c
+++ b/src/vdbemem.c
@@ -761,7 +761,7 @@ int sqlite3VdbeMemTooBig(Mem *p){
 void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
   int i;
   Mem *pX;
-  for(i=1, pX=&pVdbe->aMem[1]; i<=pVdbe->nMem; i++, pX++){
+  for(i=0, pX=pVdbe->aMem; i<pVdbe->nMem; i++, pX++){
     if( pX->pScopyFrom==pMem ){
       pX->flags |= MEM_Undefined;
       pX->pScopyFrom = 0;