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When pinning a temp register after it is reused by the column cache, make

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sure all instances of that register in the cache are pinned so that the
register is never reused for a different purpose.  Ticket #3879. (CVS 6676)

FossilOrigin-Name: 5f358e63712e8de93bd6fecc5131badeef0292be
This commit is contained in:
drh
2009-05-25 11:46:29 +00:00
parent d17fe2a352
commit 5cd792399a
3 changed files with 26 additions and 10 deletions
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20
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 1.435 2009/05/21 20:41:32 drh Exp $
** $Id: expr.c,v 1.436 2009/05/25 11:46:29 drh Exp $
*/
#include "sqliteInt.h"
@@ -1800,6 +1800,22 @@ void sqlite3ExprCachePop(Parse *pParse, int N){
}
}
/*
** When a cached column is reused, make sure that its register is
** no longer available as a temp register. ticket #3879: that same
** register might be in the cache in multiple places, so be sure to
** get them all.
*/
static void sqlite3ExprCachePinRegister(Parse *pParse, int iReg){
int i;
struct yColCache *p;
for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
if( p->iReg==iReg ){
p->tempReg = 0;
}
}
}
/*
** Generate code that will extract the iColumn-th column from
** table pTab and store the column value in a register. An effort
@@ -1835,7 +1851,7 @@ int sqlite3ExprCodeGetColumn(
VdbeComment((v, "OPT: tab%d.col%d -> r%d", iTable, iColumn, p->iReg));
#endif
p->lru = pParse->iCacheCnt++;
p->tempReg = 0; /* This pins the register, but also leaks it */
sqlite3ExprCachePinRegister(pParse, p->iReg);
return p->iReg;
}
}