Change the OP_Trace opcode to OP_Init and give it the ability to jump to the
initialization code at the bottom of the program, thus avoiding the need for
an extra OP_Goto.
FossilOrigin-Name: 192dea97316144f15f6dd0eabff08a0bf9ef203e
diff --git a/src/build.c b/src/build.c
index afd68a8..1032893 100644
--- a/src/build.c
+++ b/src/build.c
@@ -149,10 +149,11 @@
** transaction on each used database and to verify the schema cookie
** on each used database.
*/
- if( pParse->cookieGoto>0 ){
+ if( db->mallocFailed==0 && pParse->cookieMask ){
yDbMask mask;
- int iDb, i, addr;
- sqlite3VdbeJumpHere(v, pParse->cookieGoto-1);
+ int iDb, i;
+ assert( sqlite3VdbeGetOp(v, 0)->opcode==OP_Init );
+ sqlite3VdbeJumpHere(v, 0);
for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
if( (mask & pParse->cookieMask)==0 ) continue;
sqlite3VdbeUsesBtree(v, iDb);
@@ -184,17 +185,16 @@
sqlite3AutoincrementBegin(pParse);
/* Code constant expressions that where factored out of inner loops */
- addr = pParse->cookieGoto;
if( pParse->pConstExpr ){
ExprList *pEL = pParse->pConstExpr;
- pParse->cookieGoto = 0;
+ pParse->okConstFactor = 0;
for(i=0; i<pEL->nExpr; i++){
sqlite3ExprCode(pParse, pEL->a[i].pExpr, pEL->a[i].u.iConstExprReg);
}
}
/* Finally, jump back to the beginning of the executable code. */
- sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, 1);
}
}
@@ -217,7 +217,6 @@
pParse->nSet = 0;
pParse->nVar = 0;
pParse->cookieMask = 0;
- pParse->cookieGoto = 0;
}
/*
@@ -3826,59 +3825,29 @@
}
/*
-** Generate VDBE code that will verify the schema cookie and start
-** a read-transaction for all named database files.
-**
-** It is important that all schema cookies be verified and all
-** read transactions be started before anything else happens in
-** the VDBE program. But this routine can be called after much other
-** code has been generated. So here is what we do:
-**
-** The first time this routine is called, we code an OP_Goto that
-** will jump to a subroutine at the end of the program. Then we
-** record every database that needs its schema verified in the
-** pParse->cookieMask field. Later, after all other code has been
-** generated, the subroutine that does the cookie verifications and
-** starts the transactions will be coded and the OP_Goto P2 value
-** will be made to point to that subroutine. The generation of the
-** cookie verification subroutine code happens in sqlite3FinishCoding().
-**
-** If iDb<0 then code the OP_Goto only - don't set flag to verify the
-** schema on any databases. This can be used to position the OP_Goto
-** early in the code, before we know if any database tables will be used.
+** Record the fact that the schema cookie will need to be verified
+** for database iDb. The code to actually verify the schema cookie
+** will occur at the end of the top-level VDBE and will be generated
+** later, by sqlite3FinishCoding().
*/
void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
Parse *pToplevel = sqlite3ParseToplevel(pParse);
+ sqlite3 *db = pToplevel->db;
+ yDbMask mask;
-#ifndef SQLITE_OMIT_TRIGGER
- if( pToplevel!=pParse ){
- /* This branch is taken if a trigger is currently being coded. In this
- ** case, set cookieGoto to a non-zero value to show that this function
- ** has been called. This is used by the sqlite3ExprCodeConstants()
- ** function. */
- pParse->cookieGoto = -1;
- }
-#endif
- if( pToplevel->cookieGoto==0 ){
- Vdbe *v = sqlite3GetVdbe(pToplevel);
- if( v==0 ) return; /* This only happens if there was a prior error */
- pToplevel->cookieGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0)+1;
- }
- if( iDb>=0 ){
- sqlite3 *db = pToplevel->db;
- yDbMask mask;
-
- assert( iDb<db->nDb );
- assert( db->aDb[iDb].pBt!=0 || iDb==1 );
- assert( iDb<SQLITE_MAX_ATTACHED+2 );
- assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
- mask = ((yDbMask)1)<<iDb;
- if( (pToplevel->cookieMask & mask)==0 ){
- pToplevel->cookieMask |= mask;
- pToplevel->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
- if( !OMIT_TEMPDB && iDb==1 ){
- sqlite3OpenTempDatabase(pToplevel);
- }
+ assert( iDb>=0 && iDb<db->nDb );
+ assert( db->aDb[iDb].pBt!=0 || iDb==1 );
+ assert( iDb<SQLITE_MAX_ATTACHED+2 );
+ assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+ mask = ((yDbMask)1)<<iDb;
+ if( (pToplevel->cookieMask & mask)==0 ){
+ pToplevel->cookieMask |= mask;
+ pToplevel->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
+ if( !OMIT_TEMPDB && iDb==1 ){
+ sqlite3OpenTempDatabase(pToplevel);
+ }
+ if( pToplevel==pParse && OptimizationEnabled(db,SQLITE_FactorOutConst) ){
+ pParse->okConstFactor = 1;
}
}
}
diff --git a/src/insert.c b/src/insert.c
index 5dbdf91..bd15832 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -2038,7 +2038,7 @@
sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
}
- sqlite3VdbeJumpHere(v, emptySrcTest);
+ if( emptySrcTest ) sqlite3VdbeJumpHere(v, emptySrcTest);
sqlite3ReleaseTempReg(pParse, regRowid);
sqlite3ReleaseTempReg(pParse, regData);
if( emptyDestTest ){
diff --git a/src/select.c b/src/select.c
index c0728f8..8e5e4dd 100644
--- a/src/select.c
+++ b/src/select.c
@@ -1615,11 +1615,7 @@
Vdbe *v = pParse->pVdbe;
if( v==0 ){
v = pParse->pVdbe = sqlite3VdbeCreate(pParse);
-#ifndef SQLITE_OMIT_TRACE
- if( v ){
- sqlite3VdbeAddOp0(v, OP_Trace);
- }
-#endif
+ if( v ) sqlite3VdbeAddOp0(v, OP_Init);
}
return v;
}
@@ -4537,15 +4533,6 @@
*/
int addrTop;
pItem->regReturn = ++pParse->nMem;
- /* Before coding the OP_Goto to jump to the start of the main routine,
- ** ensure that the jump to the verify-schema routine has already
- ** been coded. Otherwise, the verify-schema would likely be coded as
- ** part of the co-routine. If the main routine then accessed the
- ** database before invoking the co-routine for the first time (for
- ** example to initialize a LIMIT register from a sub-select), it would
- ** be doing so without having verified the schema version and obtained
- ** the required db locks. See ticket d6b36be38. */
- sqlite3CodeVerifySchema(pParse, -1);
sqlite3VdbeAddOp0(v, OP_Goto);
addrTop = sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor);
sqlite3VdbeChangeP5(v, 1);
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 45a3986..42851ab 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1088,8 +1088,7 @@
** Return true if it OK to factor constant expressions into the initialization
** code. The argument is a Parse object for the code generator.
*/
-#define ConstFactorOk(P) \
- ((P)->cookieGoto>0 && OptimizationEnabled((P)->db,SQLITE_FactorOutConst))
+#define ConstFactorOk(P) ((P)->okConstFactor)
/*
** Possible values for the sqlite.magic field.
@@ -2354,6 +2353,7 @@
u8 isMultiWrite; /* True if statement may modify/insert multiple rows */
u8 mayAbort; /* True if statement may throw an ABORT exception */
u8 hasCompound; /* Need to invoke convertCompoundSelectToSubquery() */
+ u8 okConstFactor; /* OK to factor out constants */
int aTempReg[8]; /* Holding area for temporary registers */
int nRangeReg; /* Size of the temporary register block */
int iRangeReg; /* First register in temporary register block */
@@ -2382,7 +2382,6 @@
Token constraintName;/* Name of the constraint currently being parsed */
yDbMask writeMask; /* Start a write transaction on these databases */
yDbMask cookieMask; /* Bitmask of schema verified databases */
- int cookieGoto; /* Address of OP_Goto to cookie verifier subroutine */
int cookieValue[SQLITE_MAX_ATTACHED+2]; /* Values of cookies to verify */
int regRowid; /* Register holding rowid of CREATE TABLE entry */
int regRoot; /* Register holding root page number for new objects */
diff --git a/src/trigger.c b/src/trigger.c
index fdc2a03..cbc87ab 100644
--- a/src/trigger.c
+++ b/src/trigger.c
@@ -726,15 +726,7 @@
** INSERT OR IGNORE INTO t1 ... ; -- insert into t2 uses IGNORE policy
*/
pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf;
-
- /* Clear the cookieGoto flag. When coding triggers, the cookieGoto
- ** variable is used as a flag to indicate to sqlite3ExprCodeConstants()
- ** that it is not safe to refactor constants (this happens after the
- ** start of the first loop in the SQL statement is coded - at that
- ** point code may be conditionally executed, so it is no longer safe to
- ** initialize constant register values). */
- assert( pParse->cookieGoto==0 || pParse->cookieGoto==-1 );
- pParse->cookieGoto = 0;
+ assert( pParse->okConstFactor==0 );
switch( pStep->op ){
case TK_UPDATE: {
diff --git a/src/vdbe.c b/src/vdbe.c
index 8067f9a..657b9a7 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -6144,16 +6144,26 @@
#endif
-#ifndef SQLITE_OMIT_TRACE
-/* Opcode: Trace * * * P4 *
+/* Opcode: Init * P2 * P4 *
+** Synopsis: Start at P2
+**
+** Programs contain a single instance of this opcode as the very first
+** opcode.
**
** If tracing is enabled (by the sqlite3_trace()) interface, then
** the UTF-8 string contained in P4 is emitted on the trace callback.
+** Or if P4 is blank, use the string returned by sqlite3_sql().
+**
+** If P2 is not zero, jump to instruction P2.
*/
-case OP_Trace: {
+case OP_Init: { /* jump */
char *zTrace;
char *z;
+ if( pOp->p2 ){
+ pc = pOp->p2 - 1;
+ }
+#ifndef SQLITE_OMIT_TRACE
if( db->xTrace
&& !p->doingRerun
&& (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
@@ -6179,9 +6189,9 @@
sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
}
#endif /* SQLITE_DEBUG */
+#endif /* SQLITE_OMIT_TRACE */
break;
}
-#endif
/* Opcode: Noop * * * * *
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index 59b766a..1904cf1 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -863,14 +863,6 @@
** this routine is a valid pointer. But because the dummy.opcode is 0,
** dummy will never be written to. This is verified by code inspection and
** by running with Valgrind.
-**
-** About the #ifdef SQLITE_OMIT_TRACE: Normally, this routine is never called
-** unless p->nOp>0. This is because in the absense of SQLITE_OMIT_TRACE,
-** an OP_Trace instruction is always inserted by sqlite3VdbeGet() as soon as
-** a new VDBE is created. So we are free to set addr to p->nOp-1 without
-** having to double-check to make sure that the result is non-negative. But
-** if SQLITE_OMIT_TRACE is defined, the OP_Trace is omitted and we do need to
-** check the value of p->nOp-1 before continuing.
*/
VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
/* C89 specifies that the constant "dummy" will be initialized to all
@@ -878,9 +870,6 @@
static VdbeOp dummy; /* Ignore the MSVC warning about no initializer */
assert( p->magic==VDBE_MAGIC_INIT );
if( addr<0 ){
-#ifdef SQLITE_OMIT_TRACE
- if( p->nOp==0 ) return (VdbeOp*)&dummy;
-#endif
addr = p->nOp - 1;
}
assert( (addr>=0 && addr<p->nOp) || p->db->mallocFailed );
@@ -1465,7 +1454,7 @@
z = p->zSql;
}else if( p->nOp>=1 ){
const VdbeOp *pOp = &p->aOp[0];
- if( pOp->opcode==OP_Trace && pOp->p4.z!=0 ){
+ if( pOp->opcode==OP_Init && pOp->p4.z!=0 ){
z = pOp->p4.z;
while( sqlite3Isspace(*z) ) z++;
}
@@ -1484,7 +1473,7 @@
if( sqlite3IoTrace==0 ) return;
if( nOp<1 ) return;
pOp = &p->aOp[0];
- if( pOp->opcode==OP_Trace && pOp->p4.z!=0 ){
+ if( pOp->opcode==OP_Init && pOp->p4.z!=0 ){
int i, j;
char z[1000];
sqlite3_snprintf(sizeof(z), z, "%s", pOp->p4.z);
diff --git a/src/where.c b/src/where.c
index 9abe3ad..91ab697 100644
--- a/src/where.c
+++ b/src/where.c
@@ -5436,7 +5436,6 @@
initMaskSet(pMaskSet);
whereClauseInit(&pWInfo->sWC, pWInfo);
whereSplit(&pWInfo->sWC, pWhere, TK_AND);
- sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
/* Special case: a WHERE clause that is constant. Evaluate the
** expression and either jump over all of the code or fall thru.
@@ -5725,7 +5724,7 @@
sqlite3VdbeSetP4KeyInfo(pParse, pIx);
VdbeComment((v, "%s", pIx->zName));
}
- sqlite3CodeVerifySchema(pParse, iDb);
+ if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);
notReady &= ~getMask(&pWInfo->sMaskSet, pTabItem->iCursor);
}
pWInfo->iTop = sqlite3VdbeCurrentAddr(v);