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Only evaluate expressions once for UPDATE and INSERT statements that

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have BEFORE triggers.  Fix for ticket #980. (CVS 2158)

FossilOrigin-Name: 4852186aca3be6ea40069b6831079197e5fa757a
This commit is contained in:
drh
2004-12-07 15:41:48 +00:00
parent dca7684141
commit 2530378003
7 changed files with 127 additions and 18 deletions
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27
src/expr.c
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@@ -12,7 +12,7 @@
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.174 2004/11/23 01:47:30 drh Exp $
** $Id: expr.c,v 1.175 2004/12/07 15:41:49 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
@@ -1547,6 +1547,31 @@ void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
}
}
/*
** Generate code that evalutes the given expression and leaves the result
** on the stack. See also sqlite3ExprCode().
**
** This routine might also cache the result and modify the pExpr tree
** so that it will make use of the cached result on subsequent evaluations
** rather than evaluate the whole expression again. Trivial expressions are
** not cached. If the expression is cached, its result is stored in a
** memory location.
*/
void sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr){
Vdbe *v = pParse->pVdbe;
int iMem;
int addr1, addr2;
if( v==0 ) return;
addr1 = sqlite3VdbeCurrentAddr(v);
sqlite3ExprCode(pParse, pExpr);
addr2 = sqlite3VdbeCurrentAddr(v);
if( addr2>addr1+1 || sqlite3VdbeGetOp(v, addr1)->opcode==OP_Function ){
iMem = pExpr->iTable = pParse->nMem++;
sqlite3VdbeAddOp(v, OP_MemStore, iMem, 0);
pExpr->op = TK_REGISTER;
}
}
/*
** Generate code that pushes the value of every element of the given
** expression list onto the stack.