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Change the OP_Trace opcode to OP_Init and give it the ability to jump to the

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initialization code at the bottom of the program, thus avoiding the need for
an extra OP_Goto.

FossilOrigin-Name: 192dea97316144f15f6dd0eabff08a0bf9ef203e
This commit is contained in:
drh
2014-02-08 01:40:27 +00:00
parent 642364a48b
commit aceb31b120
10 changed files with 61 additions and 117 deletions
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81
src/build.c
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@@ -149,10 +149,11 @@ void sqlite3FinishCoding(Parse *pParse){
** 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 @@ void sqlite3FinishCoding(Parse *pParse){
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 @@ void sqlite3FinishCoding(Parse *pParse){
pParse->nSet = 0;
pParse->nVar = 0;
pParse->cookieMask = 0;
pParse->cookieGoto = 0;
}
/*
@@ -3826,59 +3825,29 @@ int sqlite3OpenTempDatabase(Parse *pParse){
}
/*
** 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;
}
}
}