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When one or more arguments to a function are constants, try to factor

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out just those arguments into initialization code.

FossilOrigin-Name: 50d350abbc9176cd6fc606bc45b8fc3020719500
This commit is contained in:
drh
2013-11-21 16:08:52 +00:00
parent 10f468f37a
commit d1a01edac9
5 changed files with 63 additions and 31 deletions
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66
src/expr.c
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@@ -2681,8 +2681,21 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
break;
}
for(i=0; i<nFarg; i++){
if( i<32 && sqlite3ExprIsConstant(pFarg->a[i].pExpr) ){
constMask |= (1<<i);
}
if( (pDef->funcFlags & SQLITE_FUNC_NEEDCOLL)!=0 && !pColl ){
pColl = sqlite3ExprCollSeq(pParse, pFarg->a[i].pExpr);
}
}
if( pFarg ){
r1 = sqlite3GetTempRange(pParse, nFarg);
if( constMask ){
r1 = pParse->nMem+1;
pParse->nMem += nFarg;
}else{
r1 = sqlite3GetTempRange(pParse, nFarg);
}
/* For length() and typeof() functions with a column argument,
** set the P5 parameter to the OP_Column opcode to OPFLAG_LENGTHARG
@@ -2704,7 +2717,8 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
}
sqlite3ExprCachePush(pParse); /* Ticket 2ea2425d34be */
sqlite3ExprCodeExprList(pParse, pFarg, r1, 1);
sqlite3ExprCodeExprList(pParse, pFarg, r1,
SQLITE_ECEL_DUP|SQLITE_ECEL_FACTOR);
sqlite3ExprCachePop(pParse, 1); /* Ticket 2ea2425d34be */
}else{
r1 = 0;
@@ -2728,14 +2742,6 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[0].pExpr);
}
#endif
for(i=0; i<nFarg; i++){
if( i<32 && sqlite3ExprIsConstant(pFarg->a[i].pExpr) ){
constMask |= (1<<i);
}
if( (pDef->funcFlags & SQLITE_FUNC_NEEDCOLL)!=0 && !pColl ){
pColl = sqlite3ExprCollSeq(pParse, pFarg->a[i].pExpr);
}
}
if( pDef->funcFlags & SQLITE_FUNC_NEEDCOLL ){
if( !pColl ) pColl = db->pDfltColl;
sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
@@ -2743,7 +2749,7 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
sqlite3VdbeAddOp4(v, OP_Function, constMask, r1, target,
(char*)pDef, P4_FUNCDEF);
sqlite3VdbeChangeP5(v, (u8)nFarg);
if( nFarg ){
if( nFarg && constMask==0 ){
sqlite3ReleaseTempRange(pParse, r1, nFarg);
}
break;
@@ -2980,6 +2986,19 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
return inReg;
}
/*
** Factor out the code of the given expression to initialization time.
*/
void sqlite3ExprCodeAtInit(Parse *pParse, Expr *pExpr, int regDest){
ExprList *p;
assert( pParse->cookieGoto>0 ); /* Only possible if cookie will be coded */
p = pParse->pConstExpr;
pExpr = sqlite3ExprDup(pParse->db, pExpr, 0);
p = sqlite3ExprListAppend(pParse, p, pExpr);
if( p ) p->a[p->nExpr-1].u.iConstExprReg = regDest;
pParse->pConstExpr = p;
}
/*
** Generate code to evaluate an expression and store the results
** into a register. Return the register number where the results
@@ -3010,10 +3029,8 @@ int sqlite3ExprCodeTemp(Parse *pParse, Expr *pExpr, int *pReg){
}
}
}
p = sqlite3ExprListAppend(pParse, p, sqlite3ExprDup(pParse->db, pExpr, 0));
pParse->pConstExpr = p;
r2 = ++pParse->nMem;
if( p ) p->a[p->nExpr-1].u.iConstExprReg = r2;
sqlite3ExprCodeAtInit(pParse, pExpr, r2);
}else{
int r1 = sqlite3GetTempReg(pParse);
r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
@@ -3358,25 +3375,36 @@ void sqlite3ExplainExprList(Vdbe *pOut, ExprList *pList){
** expression list into a sequence of registers beginning at target.
**
** Return the number of elements evaluated.
**
** The SQLITE_ECEL_DUP flag prevents the arguments from being
** filled using OP_SCopy. OP_Copy must be used instead.
**
** The SQLITE_ECEL_FACTOR argument allows constant arguments to be
** factored out into initialization code.
*/
int sqlite3ExprCodeExprList(
Parse *pParse, /* Parsing context */
ExprList *pList, /* The expression list to be coded */
int target, /* Where to write results */
int doHardCopy /* Make a hard copy of every element */
u8 flags /* SQLITE_ECEL_* flags */
){
struct ExprList_item *pItem;
int i, n;
u8 copyOp = (flags & SQLITE_ECEL_DUP) ? OP_Copy : OP_SCopy;
assert( pList!=0 );
assert( target>0 );
assert( pParse->pVdbe!=0 ); /* Never gets this far otherwise */
n = pList->nExpr;
if( pParse->cookieGoto<=0 ) flags &= ~SQLITE_ECEL_FACTOR;
for(pItem=pList->a, i=0; i<n; i++, pItem++){
Expr *pExpr = pItem->pExpr;
int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
if( inReg!=target+i ){
sqlite3VdbeAddOp2(pParse->pVdbe, doHardCopy ? OP_Copy : OP_SCopy,
inReg, target+i);
if( (flags & SQLITE_ECEL_FACTOR)!=0 && sqlite3ExprIsConstant(pExpr) ){
sqlite3ExprCodeAtInit(pParse, pExpr, target+i);
}else{
int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
if( inReg!=target+i ){
sqlite3VdbeAddOp2(pParse->pVdbe, copyOp, inReg, target+i);
}
}
}
return n;