Tracing: Don't rebuild flame graph if there is nothing to see

If the root size is 0, none of the nodes will be visible. Don't create
them in the first place.

Task-number: QTCREATORBUG-20772
Change-Id: I9595daece2d17fe8202b322ffafd361d6fa422fa
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

1 files changed, 7 insertions, 5 deletions

diff --git a/src/libs/tracing/flamegraph.cpp b/src/libs/tracing/flamegraph.cpp
index 9d7df037f5..0e454cdbb7 100644
--- a/src/libs/tracing/flamegraph.cpp
+++ b/src/libs/tracing/flamegraph.cpp
@@ -185,11 +185,13 @@ void FlameGraph::rebuild()
         return;
     }
 
-    if (m_root.isValid()) {
-        QObject *parentObject = appendChild(this, this, qmlContext(this), m_root, 0, 1);
-        m_depth = buildNode(m_root, parentObject, 1, m_maximumDepth);
-    } else {
-        m_depth = buildNode(m_root, this, 0, m_maximumDepth);
+    if (m_model->data(m_root, m_sizeRole).toReal() > 0) {
+        if (m_root.isValid()) {
+            QObject *parentObject = appendChild(this, this, qmlContext(this), m_root, 0, 1);
+            m_depth = buildNode(m_root, parentObject, 1, m_maximumDepth);
+        } else {
+            m_depth = buildNode(m_root, this, 0, m_maximumDepth);
+        }
     }
 
     emit depthChanged(m_depth);