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Simplifications and optimizations to the Expr object duplication logic.

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The 5x multiplier crutch from [f371e4c0f8ea73ae] is still present.  More
fixes are still needed.

FossilOrigin-Name: 56142a78163b755f16afc05201f623a7a19d9a4b0620a67f7fa20d2a965a288d
This commit is contained in:
drh
2023-10-20 15:47:30 +00:00
parent 0a261eb4bb
commit 90e4a3b7fc
4 changed files with 40 additions and 25 deletions
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45
src/expr.c
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@@ -1529,25 +1529,21 @@ static int dupedExprNodeSize(const Expr *p, int flags){
/*
** Return the number of bytes required to create a duplicate of the
** expression passed as the first argument. The second argument is a
** mask containing EXPRDUP_XXX flags.
** expression passed as the first argument.
**
** The value returned includes space to create a copy of the Expr struct
** itself and the buffer referred to by Expr.u.zToken, if any.
**
** If the EXPRDUP_REDUCE flag is set, then the return value includes
** space to duplicate all Expr nodes in the tree formed by Expr.pLeft
** and Expr.pRight variables (but not for any structures pointed to or
** descended from the Expr.x.pList or Expr.x.pSelect variables).
** The return value includes space to duplicate all Expr nodes in the
** tree formed by Expr.pLeft and Expr.pRight, but not any other
** substructure such as Expr.x.pList, Expr.x.pSelect, and Expr.y.pWin.
*/
static int dupedExprSize(const Expr *p, int flags){
int nByte = 0;
if( p ){
nByte = dupedExprNodeSize(p, flags);
if( flags&EXPRDUP_REDUCE ){
nByte += dupedExprSize(p->pLeft, flags) + dupedExprSize(p->pRight, flags);
}
}
static int dupedExprSize(const Expr *p){
int nByte;
assert( p!=0 );
nByte = dupedExprNodeSize(p, EXPRDUP_REDUCE);
if( p->pLeft ) nByte += dupedExprSize(p->pLeft);
if( p->pRight ) nByte += dupedExprSize(p->pRight);
return nByte;
}
@@ -1564,6 +1560,13 @@ static Expr *exprDup(sqlite3 *db, const Expr *p, int dupFlags, u8 **pzBuffer){
u8 *zAlloc; /* Memory space from which to build Expr object */
u32 staticFlag; /* EP_Static if space not obtained from malloc */
#ifdef SQLITE_DEBUG
/* If zEnd is not NULL, then it is the first byte past the end of the
** zAlloc buffer allocated by this routine. Used inside assert()
** to ensure that sufficient space was allocated for zAlloc */
u8 *zEnd = 0;
#endif
assert( db!=0 );
assert( p );
assert( dupFlags==0 || dupFlags==EXPRDUP_REDUCE );
@@ -1574,8 +1577,13 @@ static Expr *exprDup(sqlite3 *db, const Expr *p, int dupFlags, u8 **pzBuffer){
zAlloc = *pzBuffer;
staticFlag = EP_Static;
assert( zAlloc!=0 );
assert( dupFlags==EXPRDUP_REDUCE );
}else{
zAlloc = sqlite3DbMallocRawNN(db, dupedExprSize(p, dupFlags)*5);
int nAlloc = dupFlags ? dupedExprSize(p) : dupedExprNodeSize(p, 0);
zAlloc = sqlite3DbMallocRawNN(db, nAlloc*5);
#ifdef SQLITE_DEBUG
zEnd = zAlloc ? zAlloc+nAlloc : 0;
#endif
staticFlag = 0;
}
pNew = (Expr *)zAlloc;
@@ -1597,12 +1605,14 @@ static Expr *exprDup(sqlite3 *db, const Expr *p, int dupFlags, u8 **pzBuffer){
if( dupFlags ){
assert( ExprHasProperty(p, EP_Reduced)==0 );
memcpy(zAlloc, p, nNewSize);
zAlloc += nNewSize;
}else{
u32 nSize = (u32)exprStructSize(p);
memcpy(zAlloc, p, nSize);
if( nSize<EXPR_FULLSIZE ){
memset(&zAlloc[nSize], 0, EXPR_FULLSIZE-nSize);
}
zAlloc += EXPR_FULLSIZE;
}
/* Set the EP_Reduced, EP_TokenOnly, and EP_Static flags appropriately. */
@@ -1616,8 +1626,9 @@ static Expr *exprDup(sqlite3 *db, const Expr *p, int dupFlags, u8 **pzBuffer){
/* Copy the p->u.zToken string, if any. */
if( nToken ){
char *zToken = pNew->u.zToken = (char*)&zAlloc[nNewSize];
char *zToken = pNew->u.zToken = (char*)zAlloc;
memcpy(zToken, p->u.zToken, nToken);
zAlloc += nToken;
}
if( 0==((p->flags|pNew->flags) & (EP_TokenOnly|EP_Leaf)) ){
@@ -1632,7 +1643,6 @@ static Expr *exprDup(sqlite3 *db, const Expr *p, int dupFlags, u8 **pzBuffer){
/* Fill in pNew->pLeft and pNew->pRight. */
if( ExprHasProperty(pNew, EP_Reduced|EP_TokenOnly|EP_WinFunc) ){
zAlloc += dupedExprNodeSize(p, dupFlags);
if( !ExprHasProperty(pNew, EP_TokenOnly|EP_Leaf) ){
pNew->pLeft = p->pLeft ?
exprDup(db, p->pLeft, EXPRDUP_REDUCE, &zAlloc) : 0;
@@ -1661,6 +1671,7 @@ static Expr *exprDup(sqlite3 *db, const Expr *p, int dupFlags, u8 **pzBuffer){
}
}
}
assert( zEnd==0 || zAlloc<=zEnd );
return pNew;
}