HPCC-10983 Use a simpler method of preventing recursive hoisting

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>

ecl/hql/hqlopt.cpp

@@ -283,15 +283,8 @@ IHqlExpression * CTreeOptimizer::swapNodeWithChild(IHqlExpression * parent)
 IHqlExpression * CTreeOptimizer::forceSwapNodeWithChild(IHqlExpression * parent)
 {
     OwnedHqlExpr swapped = swapNodeWithChild(parent);
-    return replaceOwnedAttribute(swapped, getNoHoistAttr());
-}
-
-IHqlExpression * CTreeOptimizer::getNoHoistAttr()
-{
-    //Ensure the attribute is unique for each call to the optimizer - otherwise it stops items being hoisted that could be.
-    if (!noHoistAttr)
-        noHoistAttr.setown(createAttribute(_noHoist_Atom, createUniqueId()));
-    return LINK(noHoistAttr);
+    queryBodyExtra(swapped)->setStopHoist();
+    return swapped.getClear();
 }
 
 IHqlExpression * CTreeOptimizer::swapNodeWithChild(IHqlExpression * parent, unsigned childIndex)
@@ -1609,6 +1602,10 @@ IHqlExpression * CTreeOptimizer::inheritUsage(IHqlExpression * newExpr, IHqlExpr
 {
     OptTransformInfo * newExtra = queryBodyExtra(newExpr);
     OptTransformInfo * oldExtra = queryBodyExtra(oldExpr);
+
+    if (oldExtra->getStopHoist())
+        newExtra->setStopHoist();
+
 #ifdef TRACE_USAGE
     if (newExpr->isDataset() || newExpr->isDatarow())
         DBGLOG("%lx inherit %d,%d (from %lx) [%s]", (unsigned)newExpr, newExtra->useCount, oldExtra->useCount, (unsigned)oldExpr, queryNode0Text(newExpr));
@@ -1785,7 +1782,7 @@ bool CTreeOptimizer::childrenAreShared(IHqlExpression * expr)
 
 bool CTreeOptimizer::isWorthMovingProjectOverLimit(IHqlExpression * project)
 {
-    if (noHoistAttr && project->queryAttribute(_noHoist_Atom) == noHoistAttr)
+    if (queryBodyExtra(project)->getStopHoist())
         return false;
 
     IHqlExpression * expr = project->queryChild(0);

ecl/hql/hqlopt.ipp

@@ -32,6 +32,9 @@ class OptTransformInfo : public NewTransformInfo
 public:
     OptTransformInfo(IHqlExpression * _expr) : NewTransformInfo(_expr) { useCount = 0; }
 
+    bool getStopHoist() { return spareByte1; }
+    void setStopHoist() { spareByte1 = true; }
+
 public:
     unsigned useCount;
 };
@@ -117,8 +120,6 @@ protected:
     inline const char * queryNode0Text(IHqlExpression * expr) { return queryChildNodeTraceText(nodeText[0], expr); }
     inline const char * queryNode1Text(IHqlExpression * expr) { return queryChildNodeTraceText(nodeText[1], expr); }
 
-    IHqlExpression * getNoHoistAttr();
-
     inline bool isAlwaysLocal() const { return (options & HOOalwayslocal) != 0; }
 
 protected:
@@ -126,7 +127,6 @@ protected:
     IErrorReceiver & errorProcessor;
     unsigned options;
     StringBuffer nodeText[2];
-    HqlExprAttr noHoistAttr;
 };