Change the OP_Next and OP_Prev opcodes so that they invoke

sqlite3BtreeNext() and sqlite3BtreePrevious() directly rather than through
a function pointer, for improved performance and a decrease in code size.

FossilOrigin-Name: 9d13cbbef3cf64f281d3e100f23f1b2ed6e8d65920c7517a84e1e4f964ceff2e

manifest

@@ -1,5 +1,5 @@
-C Spell\sfix,\sno\scode\schange
+C Change\sthe\sOP_Next\sand\sOP_Prev\sopcodes\sso\sthat\sthey\sinvoke\nsqlite3BtreeNext()\sand\ssqlite3BtreePrevious()\sdirectly\srather\sthan\sthrough\na\sfunction\spointer,\sfor\simproved\sperformance\sand\sa\sdecrease\sin\scode\ssize.
-D 2022-02-24T11:09:08.525
+D 2022-02-24T14:44:23.869
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -624,11 +624,11 @@ F src/upsert.c 8789047a8f0a601ea42fa0256d1ba3190c13746b6ba940fe2d25643a7e991937
 F src/utf.c ee39565f0843775cc2c81135751ddd93eceb91a673ea2c57f61c76f288b041a0
 F src/util.c 602fe229f32a96ceccae4f40824129669582096f7c355f53dbac156c9fecef23
 F src/vacuum.c 6c38ddc52f0619865c91dae9c441d4d48bf3040d7dc1bc5b22da1e45547ed0b3
-F src/vdbe.c e179d2d6551c6cc3dda7f6f233f9fe3d3c8da2f9bfc46eaabb4b54dc4337d3cf
+F src/vdbe.c 5ff8a23c52b38a25f5b8ae398c0a787aff6fdf49e60e675915614022862a4a0a
-F src/vdbe.h 25dabb25c7e157b84e59260cfb5b466c3ac103ede9f36f4db371332c47601abe
+F src/vdbe.h 40b26aa28d9af2ebb5a444416079688f7a9c584a7e4084164fd720f9a6bebcd2
 F src/vdbeInt.h b45599a2b59f1ce042512ab6786b0b82a8cf3002f6b0fa60b4834e2cd3ac61d8
 F src/vdbeapi.c 8863ffb5a7bac42fe9a68aaa3526ee29fc18fb02a9b27188b756de41e33856e9
-F src/vdbeaux.c 0d7659fe8cb38ce86092b9bc5131c99a834a04eb78745e54acb77d79d7af2fb5
+F src/vdbeaux.c 7c45a49f51d903488a8189b698adc4a61a3884bc176b6a86b1fd6d5d79f408f5
 F src/vdbeblob.c 5e61ce31aca17db8fb60395407457a8c1c7fb471dde405e0cd675974611dcfcd
 F src/vdbemem.c 7737f0b1c480a32b057849c804d2f21d5389649bb8be80f77ad75df700adc9a1
 F src/vdbesort.c 43756031ca7430f7aec3ef904824a7883c4ede783e51f280d99b9b65c0796e35
@@ -1875,7 +1875,7 @@ F tool/mkctimec.tcl 3147e9dfc4ad774e94f80084789ebaada9da9b6e66ddab16438cfc07999b
 F tool/mkkeywordhash.c 35bfc41adacc4aa6ef6fca7fd0c63e0ec0534b78daf4d0cfdebe398216bbffc3
 F tool/mkmsvcmin.tcl 6ecab9fe22c2c8de4d82d4c46797bda3d2deac8e763885f5a38d0c44a895ab33
 F tool/mkopcodec.tcl 33d20791e191df43209b77d37f0ff0904620b28465cca6990cf8d60da61a07ef
-F tool/mkopcodeh.tcl 130b88697da6ec5b89b41844d955d08fb62c2552e889dec8c7bcecb28d8f50bd
+F tool/mkopcodeh.tcl 5dab48c49a25452257494e9601702ab63adaba6bd54a9b382615fa52661c8f8c
 F tool/mkopts.tcl 680f785fdb09729fd9ac50632413da4eadbdf9071535e3f26d03795828ab07fa
 F tool/mkpragmatab.tcl bd07bd59d45d0f3448e123d6937e9811195f9908a51e09d774609883055bfd3d
 F tool/mkshellc.tcl df5d249617f9cc94d5c48eb0401673eb3f31f383ecbc54e8a13ca3dd97e89450
@@ -1944,8 +1944,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P ecf832f71fbaee36ee10f6da5bde19a8af9f90adbba06e8c5706d18b768bae1f
+P f2597fae3c2b8f77f98a3ba9420b309f649b4008f9530d3cfaeeba1e2bf5d8a3
-R 9a1c1f565cb49075ff57da0847a15219
+R c4f84c0b82c6a47f3e7bc22716270649
-U larrybr
+U drh
-Z 2e93185395e97365671553cf23deb2d5
+Z 3e76345e3d38fad9e71118178b08dd0f
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-f2597fae3c2b8f77f98a3ba9420b309f649b4008f9530d3cfaeeba1e2bf5d8a3
+9d13cbbef3cf64f281d3e100f23f1b2ed6e8d65920c7517a84e1e4f964ceff2e

src/vdbe.c

@@ -5888,7 +5888,7 @@ case OP_Rewind: {        /* jump */
   break;
 }
 
-/* Opcode: Next P1 P2 P3 P4 P5
+/* Opcode: Next P1 P2 P3 * P5
 **
 ** Advance cursor P1 so that it points to the next key/data pair in its
 ** table or index.  If there are no more key/value pairs then fall through
@@ -5907,15 +5907,12 @@ case OP_Rewind: {        /* jump */
 ** omitted if that index had been unique.  P3 is usually 0.  P3 is
 ** always either 0 or 1.
 **
-** P4 is always of type P4_ADVANCE. The function pointer points to
-** sqlite3BtreeNext().
-**
 ** If P5 is positive and the jump is taken, then event counter
 ** number P5-1 in the prepared statement is incremented.
 **
 ** See also: Prev
 */
-/* Opcode: Prev P1 P2 P3 P4 P5
+/* Opcode: Prev P1 P2 P3 * P5
 **
 ** Back up cursor P1 so that it points to the previous key/data pair in its
 ** table or index.  If there is no previous key/value pairs then fall through
@@ -5935,9 +5932,6 @@ case OP_Rewind: {        /* jump */
 ** omitted if that index had been unique.  P3 is usually 0.  P3 is
 ** always either 0 or 1.
 **
-** P4 is always of type P4_ADVANCE. The function pointer points to
-** sqlite3BtreePrevious().
-**
 ** If P5 is positive and the jump is taken, then event counter
 ** number P5-1 in the prepared statement is incremented.
 */
@@ -5955,7 +5949,20 @@ case OP_SorterNext: {  /* jump */
   assert( isSorter(pC) );
   rc = sqlite3VdbeSorterNext(db, pC);
   goto next_tail;
+
 case OP_Prev:          /* jump */
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  assert( pOp->p5<ArraySize(p->aCounter) );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pC->deferredMoveto==0 );
+  assert( pC->eCurType==CURTYPE_BTREE );
+  assert( pC->seekOp==OP_SeekLT || pC->seekOp==OP_SeekLE
+       || pC->seekOp==OP_Last   || pC->seekOp==OP_IfNoHope
+       || pC->seekOp==OP_NullRow);
+  rc = sqlite3BtreePrevious(pC->uc.pCursor, pOp->p3);
+  goto next_tail;
+
 case OP_Next:          /* jump */
   assert( pOp->p1>=0 && pOp->p1<p->nCursor );
   assert( pOp->p5<ArraySize(p->aCounter) );
@@ -5963,22 +5970,12 @@ case OP_Next:          /* jump */
   assert( pC!=0 );
   assert( pC->deferredMoveto==0 );
   assert( pC->eCurType==CURTYPE_BTREE );
-  assert( pOp->opcode!=OP_Next || pOp->p4.xAdvance==sqlite3BtreeNext );
+  assert( pC->seekOp==OP_SeekGT || pC->seekOp==OP_SeekGE
-  assert( pOp->opcode!=OP_Prev || pOp->p4.xAdvance==sqlite3BtreePrevious );
-
-  /* The Next opcode is only used after SeekGT, SeekGE, Rewind, and Found.
-  ** The Prev opcode is only used after SeekLT, SeekLE, and Last. */
-  assert( pOp->opcode!=OP_Next
-       || pC->seekOp==OP_SeekGT || pC->seekOp==OP_SeekGE
        || pC->seekOp==OP_Rewind || pC->seekOp==OP_Found
        || pC->seekOp==OP_NullRow|| pC->seekOp==OP_SeekRowid
        || pC->seekOp==OP_IfNoHope);
-  assert( pOp->opcode!=OP_Prev
+  rc = sqlite3BtreeNext(pC->uc.pCursor, pOp->p3);
-       || pC->seekOp==OP_SeekLT || pC->seekOp==OP_SeekLE
-       || pC->seekOp==OP_Last   || pC->seekOp==OP_IfNoHope
-       || pC->seekOp==OP_NullRow);
 
-  rc = pOp->p4.xAdvance(pC->uc.pCursor, pOp->p3);
 next_tail:
   pC->cacheStatus = CACHE_STALE;
   VdbeBranchTaken(rc==SQLITE_OK,2);

src/vdbe.h

@@ -63,7 +63,6 @@ struct VdbeOp {
 #ifdef SQLITE_ENABLE_CURSOR_HINTS
     Expr *pExpr;           /* Used when p4type is P4_EXPR */
 #endif
-    int (*xAdvance)(BtCursor *, int);
   } p4;
 #ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
   char *zComment;          /* Comment to improve readability */
@@ -114,7 +113,7 @@ typedef struct VdbeOpList VdbeOpList;
 #define P4_COLLSEQ    (-2)  /* P4 is a pointer to a CollSeq structure */
 #define P4_INT32      (-3)  /* P4 is a 32-bit signed integer */
 #define P4_SUBPROGRAM (-4)  /* P4 is a pointer to a SubProgram structure */
-#define P4_ADVANCE    (-5)  /* P4 is a pointer to BtreeNext() or BtreePrev() */
+/*                    (-5)  // Available for reuse.  Was P4_ADVANCE */
 #define P4_TABLE      (-6)  /* P4 is a pointer to a Table structure */
 /* Above do not own any resources.  Must free those below */
 #define P4_FREE_IF_LE (-7)

src/vdbeaux.c

@@ -782,7 +782,7 @@ void sqlite3VdbeAssertAbortable(Vdbe *p){
 ** (3) Update the Vdbe.readOnly and Vdbe.bIsReader flags to accurately
 **     indicate what the prepared statement actually does.
 **
-** (4) Initialize the p4.xAdvance pointer on opcodes that use it.
+** (4) (discontinued)
 **
 ** (5) Reclaim the memory allocated for storing labels.
 **
@@ -828,25 +828,6 @@ static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
           p->bIsReader = 1;
           break;
         }
-        case OP_Next:
-        case OP_SorterNext: {
-          pOp->p4.xAdvance = sqlite3BtreeNext;
-          pOp->p4type = P4_ADVANCE;
-          /* The code generator never codes any of these opcodes as a jump
-          ** to a label.  They are always coded as a jump backwards to a 
-          ** known address */
-          assert( pOp->p2>=0 );
-          break;
-        }
-        case OP_Prev: {
-          pOp->p4.xAdvance = sqlite3BtreePrevious;
-          pOp->p4type = P4_ADVANCE;
-          /* The code generator never codes any of these opcodes as a jump
-          ** to a label.  They are always coded as a jump backwards to a 
-          ** known address */
-          assert( pOp->p2>=0 );
-          break;
-        }
 #ifndef SQLITE_OMIT_VIRTUALTABLE
         case OP_VUpdate: {
           if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
@@ -1727,8 +1708,7 @@ char *sqlite3VdbeDisplayP4(sqlite3 *db, Op *pOp){
       zP4 = "program";
       break;
     }
-    case P4_DYNBLOB:
+    case P4_DYNBLOB: {
-    case P4_ADVANCE: {
       break;
     }
     case P4_TABLE: {

tool/mkopcodeh.tcl

@@ -158,9 +158,6 @@ set rp2v_ops {
   OP_JournalMode
   OP_VUpdate
   OP_VFilter
-  OP_Next
-  OP_SorterNext
-  OP_Prev
 }
 
 # Assign the smallest values to opcodes that are processed by resolveP2Values()