void CseSpotter::analyseExpr(IHqlExpression * expr)
{
CseSpotterInfo * extra = queryBodyExtra(expr);
if (!extra->annotatedExpr && expr->isAnnotation())
extra->annotatedExpr = expr;
if (isAssociated)
extra->numAssociatedRefs++;
node_operator op = expr->getOperator();
#ifdef OPTIMIZE_INVERSE
if (getInverseOp(op) != no_none)
{
OwnedHqlExpr inverse = getInverse(expr);
CseSpotterInfo * inverseExtra = queryBodyExtra(inverse);
extra->inverse = inverseExtra;
inverseExtra->inverse = extra;
}
#endif
if (op == no_alias)
{
queryBodyExtra(expr->queryChild(0))->alreadyAliased = true;
extra->alreadyAliased = true;
}
switch (op)
{
case no_assign:
case no_transform:
case no_newtransform:
case no_range:
case no_rangefrom:
if (expr->isConstant())
return;
break;
case no_constant:
return;
}
if (extra->numRefs++ != 0)
{
if (op == no_alias)
return;
if (!spottedCandidate && extra->worthAliasing())
spottedCandidate = true;
if (canCreateTemporary(expr))
return;
//Ugly! This is here as a temporary hack to stop branches of maps being commoned up and always
//evaluated. The alias spotting and generation really needs to take conditionality into account....
if (op == no_mapto)
return;
}
if (!containsPotentialCSE(expr))
return;
if (canAlias && !expr->isDataset())
extra->canAlias = true;
bool savedCanAlias = canAlias;
if (expr->isDataset() && (op != no_select) && (!spotCseInIfDatasetConditions || (op != no_if)))
{
//There is little point looking for CSEs within dataset expressions, because only a very small
//minority which would correctly cse, and it can cause lots of problems - e.g., join conditions.
unsigned first = getFirstActivityArgument(expr);
unsigned num = getNumActivityArguments(expr);
HqlExprArray children;
bool defaultCanAlias = canAlias;
ForEachChild(i, expr)
{
IHqlExpression * cur = expr->queryChild(i);
if (i >= first && i < first+num)
canAlias = defaultCanAlias;
else
canAlias = false;
analyseExpr(cur);
}
inline void noteCandidate(IHqlExpression * expr) { noteCandidate(queryBodyExtra(expr)); }
