From 242f8ef98527a9e25c8b028382eb4e16fe0ae8d7 Mon Sep 17 00:00:00 2001
From: Allan Sandfeld Jensen <allan.jensen@qt.io>
Date: Tue, 11 May 2021 15:52:23 +0200
Subject: [PATCH] Avoid potential read of uninitialized clip data

Set clip->count to 0 unconditional not just when hasRegionClip or
hasRectClip is true.

Change-Id: Ib3d1c4dc24373df3d4dbc393241226a8730bb9fc
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
(cherry picked from commit 9d2850bda946fab28f689d284fd670e5cf361d8f)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/gui/painting/qpaintengine_raster.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/gui/painting/qpaintengine_raster.cpp b/src/gui/painting/qpaintengine_raster.cpp
index c527b167f68..90f4e048eda 100644
--- a/src/gui/painting/qpaintengine_raster.cpp
+++ b/src/gui/painting/qpaintengine_raster.cpp
@@ -3830,6 +3830,7 @@ void QClipData::initialize()
     Q_CHECK_PTR(m_clipLines);
     QT_TRY {
         allocated = clipSpanHeight;
+        count = 0;
         QT_TRY {
             if (hasRegionClip) {
                 const auto rects = clipRegion.begin();
@@ -3841,7 +3842,6 @@ void QClipData::initialize()
 
                 int y = 0;
                 int firstInBand = 0;
-                count = 0;
                 while (firstInBand < numRects) {
                     const int currMinY = rects[firstInBand].y();
                     const int currMaxY = currMinY + rects[firstInBand].height();
@@ -3899,7 +3899,6 @@ void QClipData::initialize()
                 }
 
                 const int len = clipRect.width();
-                count = 0;
                 while (y < ymax) {
                     QSpan *span = m_spans + count;
                     span->x = xmin;