check the validity of wxString pointer itself too

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@34896 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

diff --git a/src/msw/debughlp.cpp b/src/msw/debughlp.cpp
index cd8e486616ab2101760f19930bb3c65e9cd12788..0f72ce897c0cfab576c763861c457635c8a97dde 100644 (file)
--- a/src/msw/debughlp.cpp
+++ b/src/msw/debughlp.cpp
@@ -404,15 +404,19 @@ wxDbgHelpDLL::DumpUDT(PSYMBOL_INFO pSym, void *pVariable, unsigned level)
         // between GetWriteBuf() and UngetWriteBuf() calls) and assert when we
         // try to access it contents using public methods, so instead use our
         // knowledge of its internals
-        const wxChar *p = ps->data();
-        wxStringData *data = (wxStringData *)p - 1;
-        if ( ::IsBadReadPtr(data, sizeof(wxStringData)) ||
-                ::IsBadReadPtr(p, sizeof(wxChar *)*data->nAllocLength) )
+        const wxChar *p = NULL;
+        if ( !::IsBadReadPtr(ps, sizeof(wxString)) )
         {
-            p = _T("???");
+            p = ps->data();
+            wxStringData *data = (wxStringData *)p - 1;
+            if ( ::IsBadReadPtr(data, sizeof(wxStringData)) ||
+                    ::IsBadReadPtr(p, sizeof(wxChar *)*data->nAllocLength) )
+            {
+                p = NULL; // don't touch this pointer with 10 feet pole
+            }
         }
 
-        s << _T("(\"") << p << _T(")\"");
+        s << _T("(\"") << (p ? p : _T("???")) << _T(")\"");
     }
     else // any other UDT
 #endif // !wxUSE_STL