Re: [patch] MdeModulePkg/DisplayEngine: Remove useless NULL ptr check for NewPos

["Zeng, Star" <star.zeng@intel.com>]

Reviewed-by: Star Zeng <star.zeng@intel.com>

-----Original Message-----
From: Bi, Dandan 
Sent: Wednesday, November 7, 2018 10:53 PM
To: edk2-devel@lists.01.org
Cc: Gao, Liming <liming.gao@intel.com>; Dong, Eric <eric.dong@intel.com>; Zeng, Star <star.zeng@intel.com>; Wu, Hao A <hao.a.wu@intel.com>
Subject: [patch] MdeModulePkg/DisplayEngine: Remove useless NULL ptr check for NewPos

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1306

In function UiDisplayMenu, the NewPos ptr which used to point to the highlight menu entry. It will always point to the menu entry which need to be highlighted or the gMenuOption menu if the highlight menu is not found.
So we can remove the NULL ptr check for NewPos in this function.
And add the ASSERT code to avoid if any false positive reports of NULL pointer dereference issue raised from static analysis.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Hao Wu <hao.a.wu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
---
 MdeModulePkg/Universal/DisplayEngineDxe/FormDisplay.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Universal/DisplayEngineDxe/FormDisplay.c b/MdeModulePkg/Universal/DisplayEngineDxe/FormDisplay.c
index 7390f954b6..44f087fe01 100644
--- a/MdeModulePkg/Universal/DisplayEngineDxe/FormDisplay.c
+++ b/MdeModulePkg/Universal/DisplayEngineDxe/FormDisplay.c
@@ -2880,10 +2880,11 @@ UiDisplayMenu (
       //             MenuOption is set to NULL in Repaint
       // NewPos:     Current menu option that need to hilight
       //
       ControlFlag = CfUpdateHelpString;
 
+      ASSERT (NewPos != NULL);
       UpdateHighlightMenuInfo(NewPos, TopOfScreen, SkipValue);
 
       if (SkipHighLight) {
         SkipHighLight = FALSE;
         MenuOption    = SavedMenuOption;
@@ -2908,11 +2909,11 @@ UiDisplayMenu (
         Temp2 = SkipValue;
       } else {
         Temp2 = 0;
       }
 
-      if (NewPos != NULL && (MenuOption == NULL || NewPos != &MenuOption->Link)) {
+      if (MenuOption == NULL || NewPos != &MenuOption->Link) {
         if (MenuOption != NULL) {
           //
           // Remove the old highlight menu.
           //
           Status = DisplayOneMenu (MenuOption,
--
2.18.0.windows.1