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-rw-r--r--src/expr.c205
1 files changed, 175 insertions, 30 deletions
diff --git a/src/expr.c b/src/expr.c
index 6dcf8c3ac..6cb9c2aa1 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -2374,6 +2374,81 @@ Expr *sqlite3ExprSimplifiedAndOr(Expr *pExpr){
}
/*
+** Return true if it might be advantageous to compute the right operand
+** of expression pExpr first, before the left operand.
+**
+** Normally the left operand is computed before the right operand. But if
+** the left operand contains a subquery and the right does not, then it
+** might be more efficient to compute the right operand first.
+*/
+static int exprEvalRhsFirst(Expr *pExpr){
+ if( ExprHasProperty(pExpr->pLeft, EP_Subquery)
+ && !ExprHasProperty(pExpr->pRight, EP_Subquery)
+ ){
+ return 1;
+ }else{
+ return 0;
+ }
+}
+
+/*
+** Compute the two operands of a binary operator.
+**
+** If either operand contains a subquery, then the code strives to
+** compute the operand containing the subquery second. If the other
+** operand evalutes to NULL, then a jump is made. The address of the
+** IsNull operand that does this jump is returned. The caller can use
+** this to optimize the computation so as to avoid doing the potentially
+** expensive subquery.
+**
+** If no optimization opportunities exist, return 0.
+*/
+static int exprComputeOperands(
+ Parse *pParse, /* Parsing context */
+ Expr *pExpr, /* The comparison expression */
+ int *pR1, /* OUT: Register holding the left operand */
+ int *pR2, /* OUT: Register holding the right operand */
+ int *pFree1, /* OUT: Temp register to free if not zero */
+ int *pFree2 /* OUT: Another temp register to free if not zero */
+){
+ int addrIsNull;
+ int r1, r2;
+ Vdbe *v = pParse->pVdbe;
+
+ assert( v!=0 );
+ /*
+ ** If the left operand contains a (possibly expensive) subquery and the
+ ** right operand does not and the right operation might be NULL,
+ ** then compute the right operand first and do an IsNull jump if the
+ ** right operand evalutes to NULL.
+ */
+ if( exprEvalRhsFirst(pExpr) && sqlite3ExprCanBeNull(pExpr->pRight) ){
+ r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, pFree2);
+ addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, r2); VdbeCoverage(v);
+ }else{
+ addrIsNull = 0;
+ }
+ r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, pFree1);
+ if( addrIsNull==0 ){
+ /*
+ ** If the right operand contains a subquery and the left operand does not
+ ** and the left operand might be NULL, then check the left operand do
+ ** an IsNull check on the left operand before computing the right
+ ** operand.
+ */
+ if( ExprHasProperty(pExpr->pRight, EP_Subquery)
+ && sqlite3ExprCanBeNull(pExpr->pLeft)
+ ){
+ addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, r1); VdbeCoverage(v);
+ }
+ r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, pFree2);
+ }
+ *pR1 = r1;
+ *pR2 = r2;
+ return addrIsNull;
+}
+
+/*
** pExpr is a TK_FUNCTION node. Try to determine whether or not the
** function is a constant function. A function is constant if all of
** the following are true:
@@ -4961,11 +5036,17 @@ expr_code_doover:
case TK_NE:
case TK_EQ: {
Expr *pLeft = pExpr->pLeft;
+ int addrIsNull = 0;
if( sqlite3ExprIsVector(pLeft) ){
codeVectorCompare(pParse, pExpr, target, op, p5);
}else{
- r1 = sqlite3ExprCodeTemp(pParse, pLeft, &regFree1);
- r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+ if( ExprHasProperty(pExpr, EP_Subquery) && p5!=SQLITE_NULLEQ ){
+ addrIsNull = exprComputeOperands(pParse, pExpr,
+ &r1, &r2, &regFree1, &regFree2);
+ }else{
+ r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+ r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+ }
sqlite3VdbeAddOp2(v, OP_Integer, 1, inReg);
codeCompare(pParse, pLeft, pExpr->pRight, op, r1, r2,
sqlite3VdbeCurrentAddr(v)+2, p5,
@@ -4980,9 +5061,15 @@ expr_code_doover:
sqlite3VdbeAddOp2(v, OP_Integer, 0, inReg);
}else{
sqlite3VdbeAddOp3(v, OP_ZeroOrNull, r1, inReg, r2);
+ if( addrIsNull ){
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+2);
+ sqlite3VdbeJumpHere(v, addrIsNull);
+ sqlite3VdbeAddOp2(v, OP_Null, 0, inReg);
+ }
}
testcase( regFree1==0 );
testcase( regFree2==0 );
+
}
break;
}
@@ -4998,6 +5085,7 @@ expr_code_doover:
case TK_LSHIFT:
case TK_RSHIFT:
case TK_CONCAT: {
+ int addrIsNull;
assert( TK_AND==OP_And ); testcase( op==TK_AND );
assert( TK_OR==OP_Or ); testcase( op==TK_OR );
assert( TK_PLUS==OP_Add ); testcase( op==TK_PLUS );
@@ -5009,11 +5097,22 @@ expr_code_doover:
assert( TK_LSHIFT==OP_ShiftLeft ); testcase( op==TK_LSHIFT );
assert( TK_RSHIFT==OP_ShiftRight ); testcase( op==TK_RSHIFT );
assert( TK_CONCAT==OP_Concat ); testcase( op==TK_CONCAT );
- r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
- r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+ if( ExprHasProperty(pExpr, EP_Subquery) ){
+ addrIsNull = exprComputeOperands(pParse, pExpr,
+ &r1, &r2, &regFree1, &regFree2);
+ }else{
+ r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+ r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+ addrIsNull = 0;
+ }
sqlite3VdbeAddOp3(v, op, r2, r1, target);
testcase( regFree1==0 );
testcase( regFree2==0 );
+ if( addrIsNull ){
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+2);
+ sqlite3VdbeJumpHere(v, addrIsNull);
+ sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+ }
break;
}
case TK_UMINUS: {
@@ -5862,17 +5961,27 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
Expr *pAlt = sqlite3ExprSimplifiedAndOr(pExpr);
if( pAlt!=pExpr ){
sqlite3ExprIfTrue(pParse, pAlt, dest, jumpIfNull);
- }else if( op==TK_AND ){
- int d2 = sqlite3VdbeMakeLabel(pParse);
- testcase( jumpIfNull==0 );
- sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,
- jumpIfNull^SQLITE_JUMPIFNULL);
- sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
- sqlite3VdbeResolveLabel(v, d2);
}else{
- testcase( jumpIfNull==0 );
- sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
- sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
+ Expr *pFirst, *pSecond;
+ if( exprEvalRhsFirst(pExpr) ){
+ pFirst = pExpr->pRight;
+ pSecond = pExpr->pLeft;
+ }else{
+ pFirst = pExpr->pLeft;
+ pSecond = pExpr->pRight;
+ }
+ if( op==TK_AND ){
+ int d2 = sqlite3VdbeMakeLabel(pParse);
+ testcase( jumpIfNull==0 );
+ sqlite3ExprIfFalse(pParse, pFirst, d2,
+ jumpIfNull^SQLITE_JUMPIFNULL);
+ sqlite3ExprIfTrue(pParse, pSecond, dest, jumpIfNull);
+ sqlite3VdbeResolveLabel(v, d2);
+ }else{
+ testcase( jumpIfNull==0 );
+ sqlite3ExprIfTrue(pParse, pFirst, dest, jumpIfNull);
+ sqlite3ExprIfTrue(pParse, pSecond, dest, jumpIfNull);
+ }
}
break;
}
@@ -5911,10 +6020,16 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
case TK_GE:
case TK_NE:
case TK_EQ: {
+ int addrIsNull;
if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
- testcase( jumpIfNull==0 );
- r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
- r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+ if( ExprHasProperty(pExpr, EP_Subquery) && jumpIfNull!=SQLITE_NULLEQ ){
+ addrIsNull = exprComputeOperands(pParse, pExpr,
+ &r1, &r2, &regFree1, &regFree2);
+ }else{
+ r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+ r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+ addrIsNull = 0;
+ }
codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
r1, r2, dest, jumpIfNull, ExprHasProperty(pExpr,EP_Commuted));
assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
@@ -5929,6 +6044,13 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
VdbeCoverageIf(v, op==OP_Ne && jumpIfNull!=SQLITE_NULLEQ);
testcase( regFree1==0 );
testcase( regFree2==0 );
+ if( addrIsNull ){
+ if( jumpIfNull ){
+ sqlite3VdbeChangeP2(v, addrIsNull, dest);
+ }else{
+ sqlite3VdbeJumpHere(v, addrIsNull);
+ }
+ }
break;
}
case TK_ISNULL:
@@ -6036,17 +6158,27 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
Expr *pAlt = sqlite3ExprSimplifiedAndOr(pExpr);
if( pAlt!=pExpr ){
sqlite3ExprIfFalse(pParse, pAlt, dest, jumpIfNull);
- }else if( pExpr->op==TK_AND ){
- testcase( jumpIfNull==0 );
- sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
- sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
}else{
- int d2 = sqlite3VdbeMakeLabel(pParse);
- testcase( jumpIfNull==0 );
- sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2,
- jumpIfNull^SQLITE_JUMPIFNULL);
- sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
- sqlite3VdbeResolveLabel(v, d2);
+ Expr *pFirst, *pSecond;
+ if( exprEvalRhsFirst(pExpr) ){
+ pFirst = pExpr->pRight;
+ pSecond = pExpr->pLeft;
+ }else{
+ pFirst = pExpr->pLeft;
+ pSecond = pExpr->pRight;
+ }
+ if( pExpr->op==TK_AND ){
+ testcase( jumpIfNull==0 );
+ sqlite3ExprIfFalse(pParse, pFirst, dest, jumpIfNull);
+ sqlite3ExprIfFalse(pParse, pSecond, dest, jumpIfNull);
+ }else{
+ int d2 = sqlite3VdbeMakeLabel(pParse);
+ testcase( jumpIfNull==0 );
+ sqlite3ExprIfTrue(pParse, pFirst, d2,
+ jumpIfNull^SQLITE_JUMPIFNULL);
+ sqlite3ExprIfFalse(pParse, pSecond, dest, jumpIfNull);
+ sqlite3VdbeResolveLabel(v, d2);
+ }
}
break;
}
@@ -6088,10 +6220,16 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
case TK_GE:
case TK_NE:
case TK_EQ: {
+ int addrIsNull;
if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
- testcase( jumpIfNull==0 );
- r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
- r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+ if( ExprHasProperty(pExpr, EP_Subquery) && jumpIfNull!=SQLITE_NULLEQ ){
+ addrIsNull = exprComputeOperands(pParse, pExpr,
+ &r1, &r2, &regFree1, &regFree2);
+ }else{
+ r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+ r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+ addrIsNull = 0;
+ }
codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
r1, r2, dest, jumpIfNull,ExprHasProperty(pExpr,EP_Commuted));
assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
@@ -6106,6 +6244,13 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
VdbeCoverageIf(v, op==OP_Ne && jumpIfNull==SQLITE_NULLEQ);
testcase( regFree1==0 );
testcase( regFree2==0 );
+ if( addrIsNull ){
+ if( jumpIfNull ){
+ sqlite3VdbeChangeP2(v, addrIsNull, dest);
+ }else{
+ sqlite3VdbeJumpHere(v, addrIsNull);
+ }
+ }
break;
}
case TK_ISNULL:
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-15 23:21:58 +0000