Revert of libxml2: linearly optimize XPath expressions.

third_party/libxml/src/xpath.c

Index: third_party/libxml/src/xpath.c
diff --git a/third_party/libxml/src/xpath.c b/third_party/libxml/src/xpath.c
index 1b8587270ffc1edeef34d33f48e8ae31d95c8c6b..dc41ce6b327774adad749c3c58401f485b5a5f0c 100644
--- a/third_party/libxml/src/xpath.c
+++ b/third_party/libxml/src/xpath.c
@@ -14732,12 +14732,8 @@
 #endif /* XPATH_STREAMING */
 
 static void
-xmlXPathOptimizeExpressionInternal(xmlXPathCompExprPtr comp, xmlXPathStepOpPtr op)
+xmlXPathOptimizeExpression(xmlXPathCompExprPtr comp, xmlXPathStepOpPtr op)
 {
-    /* Already optimized? */
-    if (op->cacheURI != 0)
-        return;
-
     /*
     * Try to rewrite "descendant-or-self::node()/foo" to an optimized
     * internal representation.
@@ -14788,27 +14784,11 @@
 	}
     }
 
-    /* Mark the node. */
-    op->cacheURI = (void*)(~0);
-
     /* Recurse */
     if (op->ch1 != -1)
-        xmlXPathOptimizeExpressionInternal(comp, &comp->steps[op->ch1]);
+        xmlXPathOptimizeExpression(comp, &comp->steps[op->ch1]);
     if (op->ch2 != -1)
-	xmlXPathOptimizeExpressionInternal(comp, &comp->steps[op->ch2]);
-}
-
-static void
-xmlXPathOptimizeExpression(xmlXPathCompExprPtr comp, int root)
-{
-    int i;
-    // The expression tree/graph traversal is linear, visiting
-    // each node at most once. Mark each xmlXPathStepOp node
-    // upon visiting, taking care of clearing out the marks
-    // afterwards
-    xmlXPathOptimizeExpressionInternal(comp, &comp->steps[root]);
-    for (i = 0; i <= root; ++i)
-        comp->steps[i].cacheURI = 0;
+	xmlXPathOptimizeExpression(comp, &comp->steps[op->ch2]);
 }
 
 /**
@@ -14867,7 +14847,7 @@
 	comp->nb = 0;
 #endif
 	if ((comp->nbStep > 1) && (comp->last >= 0)) {
-	    xmlXPathOptimizeExpression(comp, comp->last);
+	    xmlXPathOptimizeExpression(comp, &comp->steps[comp->last]);
 	}
     }
     return(comp);
@@ -15049,7 +15029,8 @@
 	    (ctxt->comp->nbStep > 1) &&
 	    (ctxt->comp->last >= 0))
 	{
-	    xmlXPathOptimizeExpression(ctxt->comp, ctxt->comp->last);
+	    xmlXPathOptimizeExpression(ctxt->comp,
+		&ctxt->comp->steps[ctxt->comp->last]);
 	}
     }
     CHECK_ERROR;