Refactor the Vdbe.iVdbeMagic field into Vdbe.eVdbeState. Split the RUNNING

state into separate RUNNING and READY.  This gives a size reduction and
performance increase.

FossilOrigin-Name: 5a50a42fde9477868fad31099f5fe976437825fac44f8b3a4cf6c739c7667bbb

4 files changed, 116 insertions, 113 deletions

diff --git a/src/vdbe.c b/src/vdbe.c
index 138210943..ed781a96e 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -740,7 +740,7 @@ int sqlite3VdbeExec(
 #endif
   /*** INSERT STACK UNION HERE ***/
 
-  assert( p->iVdbeMagic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
+  assert( p->eVdbeState==VDBE_RUN_STATE );  /* sqlite3_step() verifies this */
   sqlite3VdbeEnter(p);
 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
   if( db->xProgress ){
diff --git a/src/vdbeInt.h b/src/vdbeInt.h
index 32c341eb8..9247b41c3 100644
--- a/src/vdbeInt.h
+++ b/src/vdbeInt.h
@@ -418,7 +418,6 @@ struct Vdbe {
   Vdbe *pPrev,*pNext;     /* Linked list of VDBEs with the same Vdbe.db */
   Parse *pParse;          /* Parsing context used to create this Vdbe */
   ynVar nVar;             /* Number of entries in aVar[] */
-  u32 iVdbeMagic;         /* Magic number defining state of the SQL statement */
   int nMem;               /* Number of memory locations currently allocated */
   int nCursor;            /* Number of slots in apCsr[] */
   u32 cacheCtr;           /* VdbeCursor row cache generation counter */
@@ -457,6 +456,7 @@ struct Vdbe {
   u8 minWriteFileFormat;  /* Minimum file format for writable database files */
   u8 prepFlags;           /* SQLITE_PREPARE_* flags */
   u8 doingRerun;          /* True if rerunning after an auto-reprepare */
+  u8 eVdbeState;          /* On of the VDBE_*_STATE values */
   bft expired:2;          /* 1: recompile VM immediately  2: when convenient */
   bft explain:2;          /* True if EXPLAIN present on SQL command */
   bft changeCntOn:1;      /* True to update the change-counter */
@@ -487,13 +487,12 @@ struct Vdbe {
 };
 
 /*
-** The following are allowed values for Vdbe.magic
+** The following are allowed values for Vdbe.eVdbeState
 */
-#define VDBE_MAGIC_INIT     0x16bceaa5    /* Building a VDBE program */
-#define VDBE_MAGIC_RUN      0x2df20da3    /* VDBE is ready to execute */
-#define VDBE_MAGIC_HALT     0x319c2973    /* VDBE has completed execution */
-#define VDBE_MAGIC_RESET    0x48fa9f76    /* Reset and ready to run again */
-#define VDBE_MAGIC_DEAD     0x5606c3c8    /* The VDBE has been deallocated */
+#define VDBE_INIT_STATE     0   /* Prepared statement under construction */
+#define VDBE_READY_STATE    1   /* Ready to run but not yet started */
+#define VDBE_RUN_STATE      2   /* Run in progress */
+#define VDBE_HALT_STATE     3   /* Finished.  Need reset() or finalize() */
 
 /*
 ** Structure used to store the context required by the 
diff --git a/src/vdbeapi.c b/src/vdbeapi.c
index c23dd0e0c..40821c114 100644
--- a/src/vdbeapi.c
+++ b/src/vdbeapi.c
@@ -642,35 +642,6 @@ static int sqlite3Step(Vdbe *p){
   sqlite3 *db;
   int rc;
 
-  assert(p);
-  if( p->iVdbeMagic!=VDBE_MAGIC_RUN ){
-    /* We used to require that sqlite3_reset() be called before retrying
-    ** sqlite3_step() after any error or after SQLITE_DONE.  But beginning
-    ** with version 3.7.0, we changed this so that sqlite3_reset() would
-    ** be called automatically instead of throwing the SQLITE_MISUSE error.
-    ** This "automatic-reset" change is not technically an incompatibility, 
-    ** since any application that receives an SQLITE_MISUSE is broken by
-    ** definition.
-    **
-    ** Nevertheless, some published applications that were originally written
-    ** for version 3.6.23 or earlier do in fact depend on SQLITE_MISUSE 
-    ** returns, and those were broken by the automatic-reset change.  As a
-    ** a work-around, the SQLITE_OMIT_AUTORESET compile-time restores the
-    ** legacy behavior of returning SQLITE_MISUSE for cases where the 
-    ** previous sqlite3_step() returned something other than a SQLITE_LOCKED
-    ** or SQLITE_BUSY error.
-    */
-#ifdef SQLITE_OMIT_AUTORESET
-    if( (rc = p->rc&0xff)==SQLITE_BUSY || rc==SQLITE_LOCKED ){
-      sqlite3_reset((sqlite3_stmt*)p);
-    }else{
-      return SQLITE_MISUSE_BKPT;
-    }
-#else
-    sqlite3_reset((sqlite3_stmt*)p);
-#endif
-  }
-
   /* Check that malloc() has not failed. If it has, return early. */
   db = p->db;
   if( db->mallocFailed ){
@@ -678,45 +649,83 @@ static int sqlite3Step(Vdbe *p){
     return SQLITE_NOMEM_BKPT;
   }
 
-  if( p->pc<0 && p->expired ){
-    p->rc = SQLITE_SCHEMA;
-    rc = SQLITE_ERROR;
-    if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ){
-      /* If this statement was prepared using saved SQL and an 
-      ** error has occurred, then return the error code in p->rc to the
-      ** caller. Set the error code in the database handle to the same value.
-      */ 
-      rc = sqlite3VdbeTransferError(p);
-    }
-    goto end_of_step;
-  }
-  if( p->pc<0 ){
-    /* If there are no other statements currently running, then
-    ** reset the interrupt flag.  This prevents a call to sqlite3_interrupt
-    ** from interrupting a statement that has not yet started.
-    */
-    if( db->nVdbeActive==0 ){
-      AtomicStore(&db->u1.isInterrupted, 0);
-    }
+  assert(p);
+  if( p->eVdbeState!=VDBE_RUN_STATE ){
+    restart_step:
+    if( p->eVdbeState==VDBE_READY_STATE ){
+      if( p->expired ){
+        p->rc = SQLITE_SCHEMA;
+        rc = SQLITE_ERROR;
+        if( (p->prepFlags & SQLITE_PREPARE_SAVESQL)!=0 ){
+          /* If this statement was prepared using saved SQL and an 
+          ** error has occurred, then return the error code in p->rc to the
+          ** caller. Set the error code in the database handle to the same
+          ** value.
+          */ 
+          rc = sqlite3VdbeTransferError(p);
+        }
+        goto end_of_step;
+      }
 
-    assert( db->nVdbeWrite>0 || db->autoCommit==0 
-        || (db->nDeferredCons==0 && db->nDeferredImmCons==0)
-    );
+      /* If there are no other statements currently running, then
+      ** reset the interrupt flag.  This prevents a call to sqlite3_interrupt
+      ** from interrupting a statement that has not yet started.
+      */
+      if( db->nVdbeActive==0 ){
+        AtomicStore(&db->u1.isInterrupted, 0);
+      }
+
+      assert( db->nVdbeWrite>0 || db->autoCommit==0 
+          || (db->nDeferredCons==0 && db->nDeferredImmCons==0)
+      );
 
 #ifndef SQLITE_OMIT_TRACE
-    if( (db->mTrace & (SQLITE_TRACE_PROFILE|SQLITE_TRACE_XPROFILE))!=0
-        && !db->init.busy && p->zSql ){
-      sqlite3OsCurrentTimeInt64(db->pVfs, &p->startTime);
-    }else{
-      assert( p->startTime==0 );
-    }
+      if( (db->mTrace & (SQLITE_TRACE_PROFILE|SQLITE_TRACE_XPROFILE))!=0
+          && !db->init.busy && p->zSql ){
+        sqlite3OsCurrentTimeInt64(db->pVfs, &p->startTime);
+      }else{
+        assert( p->startTime==0 );
+      }
 #endif
 
-    db->nVdbeActive++;
-    if( p->readOnly==0 ) db->nVdbeWrite++;
-    if( p->bIsReader ) db->nVdbeRead++;
-    p->pc = 0;
+      db->nVdbeActive++;
+      if( p->readOnly==0 ) db->nVdbeWrite++;
+      if( p->bIsReader ) db->nVdbeRead++;
+      p->pc = 0;
+      p->eVdbeState = VDBE_RUN_STATE;
+    }else
+
+    if( ALWAYS(p->eVdbeState==VDBE_HALT_STATE) ){
+      /* We used to require that sqlite3_reset() be called before retrying
+      ** sqlite3_step() after any error or after SQLITE_DONE.  But beginning
+      ** with version 3.7.0, we changed this so that sqlite3_reset() would
+      ** be called automatically instead of throwing the SQLITE_MISUSE error.
+      ** This "automatic-reset" change is not technically an incompatibility, 
+      ** since any application that receives an SQLITE_MISUSE is broken by
+      ** definition.
+      **
+      ** Nevertheless, some published applications that were originally written
+      ** for version 3.6.23 or earlier do in fact depend on SQLITE_MISUSE 
+      ** returns, and those were broken by the automatic-reset change.  As a
+      ** a work-around, the SQLITE_OMIT_AUTORESET compile-time restores the
+      ** legacy behavior of returning SQLITE_MISUSE for cases where the 
+      ** previous sqlite3_step() returned something other than a SQLITE_LOCKED
+      ** or SQLITE_BUSY error.
+      */
+#ifdef SQLITE_OMIT_AUTORESET
+      if( (rc = p->rc&0xff)==SQLITE_BUSY || rc==SQLITE_LOCKED ){
+        sqlite3_reset((sqlite3_stmt*)p);
+      }else{
+        return SQLITE_MISUSE_BKPT;
+      }
+#else
+      sqlite3_reset((sqlite3_stmt*)p);
+#endif
+      assert( p->eVdbeState==VDBE_READY_STATE );
+      goto restart_step;
+    }
   }
+
 #ifdef SQLITE_DEBUG
   p->rcApp = SQLITE_OK;
 #endif
@@ -1428,7 +1437,7 @@ static int vdbeUnbind(Vdbe *p, int i){
     return SQLITE_MISUSE_BKPT;
   }
   sqlite3_mutex_enter(p->db->mutex);
-  if( p->iVdbeMagic!=VDBE_MAGIC_RUN || p->pc>=0 ){
+  if( p->eVdbeState!=VDBE_READY_STATE ){
     sqlite3Error(p->db, SQLITE_MISUSE);
     sqlite3_mutex_leave(p->db->mutex);
     sqlite3_log(SQLITE_MISUSE, 
@@ -1781,7 +1790,7 @@ int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt){
 */
 int sqlite3_stmt_busy(sqlite3_stmt *pStmt){
   Vdbe *v = (Vdbe*)pStmt;
-  return v!=0 && v->iVdbeMagic==VDBE_MAGIC_RUN && v->pc>=0;
+  return v!=0 && v->eVdbeState==VDBE_RUN_STATE;
 }
 
 /*
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index c5024efb1..6573efcf2 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -35,7 +35,7 @@ Vdbe *sqlite3VdbeCreate(Parse *pParse){
   p->pNext = db->pVdbe;
   p->pPrev = 0;
   db->pVdbe = p;
-  p->iVdbeMagic = VDBE_MAGIC_INIT;
+  assert( p->eVdbeState==VDBE_INIT_STATE );
   p->pParse = pParse;
   pParse->pVdbe = p;
   assert( pParse->aLabel==0 );
@@ -236,7 +236,7 @@ int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){
   VdbeOp *pOp;
 
   i = p->nOp;
-  assert( p->iVdbeMagic==VDBE_MAGIC_INIT );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
   assert( op>=0 && op<0xff );
   if( p->nOpAlloc<=i ){
     return growOp3(p, op, p1, p2, p3);
@@ -568,7 +568,7 @@ static SQLITE_NOINLINE void resizeResolveLabel(Parse *p, Vdbe *v, int j){
 void sqlite3VdbeResolveLabel(Vdbe *v, int x){
   Parse *p = v->pParse;
   int j = ADDR(x);
-  assert( v->iVdbeMagic==VDBE_MAGIC_INIT );
+  assert( v->eVdbeState==VDBE_INIT_STATE );
   assert( j<-p->nLabel );
   assert( j>=0 );
 #ifdef SQLITE_DEBUG
@@ -878,7 +878,7 @@ static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
 ** Return the address of the next instruction to be inserted.
 */
 int sqlite3VdbeCurrentAddr(Vdbe *p){
-  assert( p->iVdbeMagic==VDBE_MAGIC_INIT );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
   return p->nOp;
 }
 
@@ -963,7 +963,7 @@ VdbeOp *sqlite3VdbeAddOpList(
   int i;
   VdbeOp *pOut, *pFirst;
   assert( nOp>0 );
-  assert( p->iVdbeMagic==VDBE_MAGIC_INIT );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
   if( p->nOp + nOp > p->nOpAlloc && growOpArray(p, nOp) ){
     return 0;
   }
@@ -1289,7 +1289,7 @@ void sqlite3VdbeChangeP4(Vdbe *p, int addr, const char *zP4, int n){
   sqlite3 *db;
   assert( p!=0 );
   db = p->db;
-  assert( p->iVdbeMagic==VDBE_MAGIC_INIT );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
   assert( p->aOp!=0 || db->mallocFailed );
   if( db->mallocFailed ){
     if( n!=P4_VTAB ) freeP4(db, n, (void*)*(char**)&zP4);
@@ -1417,7 +1417,7 @@ VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
   /* C89 specifies that the constant "dummy" will be initialized to all
   ** zeros, which is correct.  MSVC generates a warning, nevertheless. */
   static VdbeOp dummy;  /* Ignore the MSVC warning about no initializer */
-  assert( p->iVdbeMagic==VDBE_MAGIC_INIT );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
   if( addr<0 ){
     addr = p->nOp - 1;
   }
@@ -2119,7 +2119,7 @@ int sqlite3VdbeList(
   Op *pOp;                             /* Current opcode */
 
   assert( p->explain );
-  assert( p->iVdbeMagic==VDBE_MAGIC_RUN );
+  assert( p->eVdbeState==VDBE_RUN_STATE );
   assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY || p->rc==SQLITE_NOMEM );
 
   /* Even though this opcode does not use dynamic strings for
@@ -2299,14 +2299,15 @@ void sqlite3VdbeRewind(Vdbe *p){
   int i;
 #endif
   assert( p!=0 );
-  assert( p->iVdbeMagic==VDBE_MAGIC_INIT || p->iVdbeMagic==VDBE_MAGIC_RESET );
+  assert( p->eVdbeState==VDBE_INIT_STATE
+       || p->eVdbeState==VDBE_READY_STATE
+       || p->eVdbeState==VDBE_HALT_STATE );
 
   /* There should be at least one opcode.
   */
   assert( p->nOp>0 );
 
-  /* Set the magic to VDBE_MAGIC_RUN sooner rather than later. */
-  p->iVdbeMagic = VDBE_MAGIC_RUN;
+  p->eVdbeState = VDBE_READY_STATE;
 
 #ifdef SQLITE_DEBUG
   for(i=0; i<p->nMem; i++){
@@ -2362,7 +2363,7 @@ void sqlite3VdbeMakeReady(
   assert( p!=0 );
   assert( p->nOp>0 );
   assert( pParse!=0 );
-  assert( p->iVdbeMagic==VDBE_MAGIC_INIT );
+  assert( p->eVdbeState==VDBE_INIT_STATE );
   assert( pParse==p->pParse );
   p->pVList = pParse->pVList;
   pParse->pVList =  0;
@@ -2503,14 +2504,12 @@ void sqlite3VdbeFreeCursor(Vdbe *p, VdbeCursor *pCx){
 ** Close all cursors in the current frame.
 */
 static void closeCursorsInFrame(Vdbe *p){
-  if( p->apCsr ){
-    int i;
-    for(i=0; i<p->nCursor; i++){
-      VdbeCursor *pC = p->apCsr[i];
-      if( pC ){
-        sqlite3VdbeFreeCursor(p, pC);
-        p->apCsr[i] = 0;
-      }
+  int i;
+  for(i=0; i<p->nCursor; i++){
+    VdbeCursor *pC = p->apCsr[i];
+    if( pC ){
+      sqlite3VdbeFreeCursor(p, pC);
+      p->apCsr[i] = 0;
     }
   }
 }
@@ -2559,9 +2558,7 @@ static void closeAllCursors(Vdbe *p){
   }
   assert( p->nFrame==0 );
   closeCursorsInFrame(p);
-  if( p->aMem ){
-    releaseMemArray(p->aMem, p->nMem);
-  }
+  releaseMemArray(p->aMem, p->nMem);
   while( p->pDelFrame ){
     VdbeFrame *pDel = p->pDelFrame;
     p->pDelFrame = pDel->pParent;
@@ -3041,7 +3038,7 @@ int sqlite3VdbeHalt(Vdbe *p){
   ** one, or the complete transaction if there is no statement transaction.
   */
 
-  if( p->iVdbeMagic!=VDBE_MAGIC_RUN ){
+  if( p->eVdbeState!=VDBE_RUN_STATE ){
     return SQLITE_OK;
   }
   if( db->mallocFailed ){
@@ -3052,7 +3049,7 @@ int sqlite3VdbeHalt(Vdbe *p){
 
   /* No commit or rollback needed if the program never started or if the
   ** SQL statement does not read or write a database file.  */
-  if( p->pc>=0 && p->bIsReader ){
+  if( p->bIsReader ){
     int mrc;   /* Primary error code from p->rc */
     int eStatementOp = 0;
     int isSpecialError;            /* Set to true if a 'special' error */
@@ -3200,15 +3197,13 @@ int sqlite3VdbeHalt(Vdbe *p){
   }
 
   /* We have successfully halted and closed the VM.  Record this fact. */
-  if( p->pc>=0 ){
-    db->nVdbeActive--;
-    if( !p->readOnly ) db->nVdbeWrite--;
-    if( p->bIsReader ) db->nVdbeRead--;
-    assert( db->nVdbeActive>=db->nVdbeRead );
-    assert( db->nVdbeRead>=db->nVdbeWrite );
-    assert( db->nVdbeWrite>=0 );
-  }
-  p->iVdbeMagic = VDBE_MAGIC_HALT;
+  db->nVdbeActive--;
+  if( !p->readOnly ) db->nVdbeWrite--;
+  if( p->bIsReader ) db->nVdbeRead--;
+  assert( db->nVdbeActive>=db->nVdbeRead );
+  assert( db->nVdbeRead>=db->nVdbeWrite );
+  assert( db->nVdbeWrite>=0 );
+  p->eVdbeState = VDBE_HALT_STATE;
   checkActiveVdbeCnt(db);
   if( db->mallocFailed ){
     p->rc = SQLITE_NOMEM_BKPT;
@@ -3290,8 +3285,8 @@ static void vdbeInvokeSqllog(Vdbe *v){
 ** again.
 **
 ** To look at it another way, this routine resets the state of the
-** virtual machine from VDBE_MAGIC_RUN or VDBE_MAGIC_HALT back to
-** VDBE_MAGIC_INIT.
+** virtual machine from VDBE_RUN_STATE or VDBE_HALT_STATE back to
+** VDBE_READY_STATE.
 */
 int sqlite3VdbeReset(Vdbe *p){
 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
@@ -3382,7 +3377,6 @@ int sqlite3VdbeReset(Vdbe *p){
     }
   }
 #endif
-  p->iVdbeMagic = VDBE_MAGIC_RESET;
   return p->rc & db->errMask;
 }
  
@@ -3392,7 +3386,10 @@ int sqlite3VdbeReset(Vdbe *p){
 */
 int sqlite3VdbeFinalize(Vdbe *p){
   int rc = SQLITE_OK;
-  if( p->iVdbeMagic==VDBE_MAGIC_RUN || p->iVdbeMagic==VDBE_MAGIC_HALT ){
+  assert( VDBE_RUN_STATE>VDBE_READY_STATE );
+  assert( VDBE_HALT_STATE>VDBE_READY_STATE );
+  assert( VDBE_INIT_STATE<VDBE_READY_STATE );
+  if( p->eVdbeState>=VDBE_READY_STATE ){
     rc = sqlite3VdbeReset(p);
     assert( (rc & p->db->errMask)==rc );
   }
@@ -3456,7 +3453,7 @@ void sqlite3VdbeClearObject(sqlite3 *db, Vdbe *p){
     vdbeFreeOpArray(db, pSub->aOp, pSub->nOp);
     sqlite3DbFree(db, pSub);
   }
-  if( p->iVdbeMagic!=VDBE_MAGIC_INIT ){
+  if( p->eVdbeState!=VDBE_INIT_STATE ){
     releaseMemArray(p->aVar, p->nVar);
     if( p->pVList ) sqlite3DbFreeNN(db, p->pVList);
     if( p->pFree ) sqlite3DbFreeNN(db, p->pFree);
@@ -3503,8 +3500,6 @@ void sqlite3VdbeDelete(Vdbe *p){
   if( p->pNext ){
     p->pNext->pPrev = p->pPrev;
   }
-  p->iVdbeMagic = VDBE_MAGIC_DEAD;
-  p->db = 0;
   sqlite3DbFreeNN(db, p);
 }