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Initialize all constants at the very beginning of a prepared statement.

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Do not allow constant initialization to occur once control flow has a chance
to diverge, to avoid the possibility of having uninitialized registers.
Ticket [80ba201079ea60807].

FossilOrigin-Name: c5c53152d68218bb5e7f922271dd7c50da2361c1
This commit is contained in:
drh
2010-12-06 18:50:32 +00:00
parent eefab7512b
commit 48b5b041d1
4 changed files with 130 additions and 9 deletions
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16
src/expr.c
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@@ -1655,6 +1655,7 @@ int sqlite3CodeSubselect(
sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
dest.affinity = (u8)affinity;
assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
pExpr->x.pSelect->iLimit = 0;
if( sqlite3Select(pParse, pExpr->x.pSelect, &dest) ){
return 0;
}
@@ -1755,6 +1756,7 @@ int sqlite3CodeSubselect(
sqlite3ExprDelete(pParse->db, pSel->pLimit);
pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0,
&sqlite3IntTokens[1]);
pSel->iLimit = 0;
if( sqlite3Select(pParse, pSel, &dest) ){
return 0;
}
@@ -3034,6 +3036,17 @@ static int evalConstExpr(Walker *pWalker, Expr *pExpr){
return WRC_Continue;
}
/* This routine is part of the parse-tree walker for
** sqlite3ExprCodeConstants(). Simply return WRC_Continue so that
** tree walker logic will extend constant extraction and precoding
** into subqueires.
*/
static int evalConstSelect(Walker *pNotUsed1, Select *pNotUsed2){
UNUSED_PARAMETER(pNotUsed1);
UNUSED_PARAMETER(pNotUsed2);
return WRC_Continue;
}
/*
** Preevaluate constant subexpressions within pExpr and store the
** results in registers. Modify pExpr so that the constant subexpresions
@@ -3041,8 +3054,9 @@ static int evalConstExpr(Walker *pWalker, Expr *pExpr){
*/
void sqlite3ExprCodeConstants(Parse *pParse, Expr *pExpr){
Walker w;
if( pParse->cookieGoto ) return;
w.xExprCallback = evalConstExpr;
w.xSelectCallback = 0;
w.xSelectCallback = evalConstSelect;
w.pParse = pParse;
sqlite3WalkExpr(&w, pExpr);
}