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Fix the CSE mechanism so that it takes into account column affinity

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changes that might be imposed by comparison operators. (CVS 4949)

FossilOrigin-Name: 91cc646e2b0c1d62a1989405cc9384a2c22d98d0
This commit is contained in:
drh
2008-04-01 05:07:14 +00:00
parent 2f7794c111
commit da250ea599
9 changed files with 106 additions and 73 deletions
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110
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 1.361 2008/04/01 03:27:39 drh Exp $
** $Id: expr.c,v 1.362 2008/04/01 05:07:15 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
@@ -201,6 +201,30 @@ CollSeq *sqlite3BinaryCompareCollSeq(
return pColl;
}
/*
** Generate the operands for a comparison operation. Before
** generating the code for each operand, set the EP_AnyAff
** flag on the expression so that it will be able to used a
** cached column value that has previously undergone an
** affinity change.
*/
static void codeCompareOperands(
Parse *pParse, /* Parsing and code generating context */
Expr *pLeft, /* The left operand */
int *pRegLeft, /* Register where left operand is stored */
int *pFreeLeft, /* Free this register when done */
Expr *pRight, /* The right operand */
int *pRegRight, /* Register where right operand is stored */
int *pFreeRight /* Write temp register for right operand there */
){
while( pLeft->op==TK_UPLUS ) pLeft = pLeft->pLeft;
pLeft->flags |= EP_AnyAff;
*pRegLeft = sqlite3ExprCodeTemp(pParse, pLeft, pFreeLeft);
while( pRight->op==TK_UPLUS ) pRight = pRight->pLeft;
pRight->flags |= EP_AnyAff;
*pRegRight = sqlite3ExprCodeTemp(pParse, pRight, pFreeRight);
}
/*
** Generate code for a comparison operator.
*/
@@ -223,8 +247,8 @@ static int codeCompare(
(void*)p4, P4_COLLSEQ);
sqlite3VdbeChangeP5(pParse->pVdbe, p5);
if( p5 & SQLITE_AFF_MASK ){
sqlite3ExprExpireColumnCacheLines(pParse, in1, in1);
sqlite3ExprExpireColumnCacheLines(pParse, in2, in2);
sqlite3ExprCacheAffinityChange(pParse, in1, 1);
sqlite3ExprCacheAffinityChange(pParse, in2, 1);
}
return addr;
}
@@ -1787,7 +1811,7 @@ void sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
sqlite3ExprCode(pParse, pE2, r1);
pParse->disableColCache--;
sqlite3VdbeAddOp4(v, OP_MakeRecord, r1, 1, r2, &affinity, 1);
sqlite3ExprExpireColumnCacheLines(pParse, r1, r1);
sqlite3ExprCacheAffinityChange(pParse, r1, 1);
sqlite3VdbeAddOp2(v, OP_IdxInsert, pExpr->iTable, r2);
}
sqlite3ReleaseTempReg(pParse, r1);
@@ -1907,26 +1931,33 @@ static void codeInteger(Vdbe *v, const char *z, int n, int negFlag, int iMem){
**
** There must be an open cursor to pTab in iTable when this routine
** is called. If iColumn<0 then code is generated that extracts the rowid.
**
** This routine might attempt to reuse the value of the column that
** has already been loaded into a register. The value will always
** be used if it has not undergone any affinity changes. But if
** an affinity change has occurred, then the cached value will only be
** used if allowAffChng is true.
*/
int sqlite3ExprCodeGetColumn(
Parse *pParse, /* Parsing and code generating context */
Table *pTab, /* Description of the table we are reading from */
int iColumn, /* Index of the table column */
int iTable, /* The cursor pointing to the table */
int iReg /* Store results here */
int iReg, /* Store results here */
int allowAffChng /* True if prior affinity changes are OK */
){
Vdbe *v = pParse->pVdbe;
int i;
struct yColCache *p;
for(i=0; i<pParse->nColCache; i++){
if( pParse->aColCache[i].iTable==iTable
&& pParse->aColCache[i].iColumn==iColumn ){
for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
if( p->iTable==iTable && p->iColumn==iColumn
&& (!p->affChange || allowAffChng) ){
#if 0
sqlite3VdbeAddOp0(v, OP_Noop);
VdbeComment((v, "OPT: tab%d.col%d -> r%d",
iTable, iColumn, pParse->aColCache[i].iReg));
VdbeComment((v, "OPT: tab%d.col%d -> r%d", iTable, iColumn, p->iReg));
#endif
return pParse->aColCache[i].iReg;
return p->iReg;
}
}
assert( v!=0 );
@@ -1947,9 +1978,10 @@ int sqlite3ExprCodeGetColumn(
}
if( pParse->disableColCache==0 ){
i = pParse->iColCache;
pParse->aColCache[i].iTable = iTable;
pParse->aColCache[i].iColumn = iColumn;
pParse->aColCache[i].iReg = iReg;
p = &pParse->aColCache[i];
p->iTable = iTable;
p->iColumn = iColumn;
p->iReg = iReg;
i++;
if( i>=ArraySize(pParse->aColCache) ) i = 0;
if( i>pParse->nColCache ) pParse->nColCache = i;
@@ -1980,30 +2012,25 @@ void sqlite3ExprClearColumnCache(Parse *pParse, int iTable){
for(i=0; i<pParse->nColCache; i++){
if( pParse->aColCache[i].iTable==iTable ){
pParse->aColCache[i] = pParse->aColCache[--pParse->nColCache];
pParse->iColCache = pParse->nColCache;
}
}
pParse->iColCache = pParse->nColCache;
}
}
/*
** Expire all column cache entry associated with register between
** iFrom and iTo, inclusive. If there are no column cache entries
** on those registers then this routine is a no-op.
**
** Call this routine when register contents are overwritten to
** make sure the new register value is not used in place of the
** value that was overwritten.
** Record the fact that an affinity change has occurred on iCount
** registers starting with iStart.
*/
void sqlite3ExprExpireColumnCacheLines(Parse *pParse, int iFrom, int iTo){
void sqlite3ExprCacheAffinityChange(Parse *pParse, int iStart, int iCount){
int iEnd = iStart + iCount - 1;
int i;
for(i=0; i<pParse->nColCache; i++){
int r = pParse->aColCache[i].iReg;
if( r>=iFrom && r<=iTo ){
pParse->aColCache[i] = pParse->aColCache[--pParse->nColCache];
if( r>=iStart && r<=iEnd ){
pParse->aColCache[i].affChange = 1;
}
}
pParse->iColCache = pParse->nColCache;
}
/*
@@ -2047,6 +2074,7 @@ static int usedAsColumnCache(Parse *pParse, int iFrom, int iTo){
** Return the register that the value ends up in.
*/
int sqlite3ExprWritableRegister(Parse *pParse, int iCurrent, int iTarget){
int i;
assert( pParse->pVdbe!=0 );
if( !usedAsColumnCache(pParse, iCurrent, iCurrent) ){
return iCurrent;
@@ -2054,7 +2082,12 @@ int sqlite3ExprWritableRegister(Parse *pParse, int iCurrent, int iTarget){
if( iCurrent!=iTarget ){
sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, iCurrent, iTarget);
}
sqlite3ExprExpireColumnCacheLines(pParse, iTarget, iTarget);
for(i=0; i<pParse->nColCache; i++){
if( pParse->aColCache[i].iReg==iTarget ){
pParse->aColCache[i] = pParse->aColCache[--pParse->nColCache];
pParse->iColCache = pParse->nColCache;
}
}
return iTarget;
}
@@ -2108,7 +2141,8 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
inReg = pExpr->iColumn + pParse->ckBase;
}else{
inReg = sqlite3ExprCodeGetColumn(pParse, pExpr->pTab,
pExpr->iColumn, pExpr->iTable, target);
pExpr->iColumn, pExpr->iTable, target,
pExpr->flags & EP_AnyAff);
}
break;
}
@@ -2185,8 +2219,8 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
assert( TK_GE==OP_Ge );
assert( TK_EQ==OP_Eq );
assert( TK_NE==OP_Ne );
r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
pExpr->pRight, &r2, &regFree2);
codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
r1, r2, inReg, SQLITE_STOREP2);
break;
@@ -2330,7 +2364,7 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
if( nExpr ){
sqlite3ReleaseTempRange(pParse, r1, nExpr);
}
sqlite3ExprExpireColumnCacheLines(pParse, r1, r1+nExpr-1);
sqlite3ExprCacheAffinityChange(pParse, r1, nExpr);
break;
}
#ifndef SQLITE_OMIT_SUBQUERY
@@ -2374,7 +2408,7 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
}else{
r2 = regFree2 = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp4(v, OP_MakeRecord, r1, 1, r2, &affinity, 1);
sqlite3ExprExpireColumnCacheLines(pParse, r1, r1);
sqlite3ExprCacheAffinityChange(pParse, r1, 1);
j5 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, r2);
}
sqlite3VdbeAddOp2(v, OP_AddImm, target, -1);
@@ -2399,8 +2433,8 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
struct ExprList_item *pLItem = pExpr->pList->a;
Expr *pRight = pLItem->pExpr;
r1 = sqlite3ExprCodeTemp(pParse, pLeft, &regFree1);
r2 = sqlite3ExprCodeTemp(pParse, pRight, &regFree2);
codeCompareOperands(pParse, pLeft, &r1, &regFree1,
pRight, &r2, &regFree2);
r3 = sqlite3GetTempReg(pParse);
r4 = sqlite3GetTempReg(pParse);
codeCompare(pParse, pLeft, pRight, OP_Ge,
@@ -2702,8 +2736,8 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
assert( TK_GE==OP_Ge );
assert( TK_EQ==OP_Eq );
assert( TK_NE==OP_Ne );
r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
pExpr->pRight, &r2, &regFree2);
codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
r1, r2, dest, jumpIfNull);
break;
@@ -2833,8 +2867,8 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
case TK_GE:
case TK_NE:
case TK_EQ: {
r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
pExpr->pRight, &r2, &regFree2);
codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
r1, r2, dest, jumpIfNull);
break;