X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/1224b8a3865f070ff541c0f1f3b889380abd087f..326b62161d387b4181b797a76652796f730172fb:/include/wx/string.h

diff --git a/include/wx/string.h b/include/wx/string.h
index b369223e71..b66afd79ae 100644
--- a/include/wx/string.h
+++ b/include/wx/string.h
@@ -594,26 +594,38 @@ private:
       unsigned lastUsed;
   };
 
-  // notice that we must use an accessor function and not a static variable
-  // because when the TLS variables support is implemented in the library (and
-  // not by the compiler), the global s_cache variable could be not yet
-  // initialized when a ctor of another global object is executed and if that
-  // ctor uses any wxString methods, bad things happen
-  static Cache& GetCache()
+#ifndef wxHAS_COMPILER_TLS
+  // we must use an accessor function and not a static variable when the TLS
+  // variables support is implemented in the library (and not by the compiler)
+  // because the global s_cache variable could be not yet initialized when a
+  // ctor of another global object is executed and if that ctor uses any
+  // wxString methods, bad things happen
+  //
+  // however notice that this approach does not work when compiler TLS is used,
+  // at least not with g++ 4.1.2 under amd64 as it apparently compiles code
+  // using this accessor incorrectly when optimizations are enabled (-O2 is
+  // enough) -- luckily we don't need it then neither as static __thread
+  // variables are initialized by 0 anyhow then and so we can use the variable
+  // directly
+  WXEXPORT static Cache& GetCache()
   {
       static wxTLS_TYPE(Cache) s_cache;
 
       return wxTLS_VALUE(s_cache);
   }
-
-  static Cache::Element *GetCacheBegin() { return GetCache().cached; }
-  static Cache::Element *GetCacheEnd() { return GetCacheBegin() + Cache::SIZE; }
-  static unsigned& LastUsedCacheElement() { return GetCache().lastUsed; }
-
+  
   // this helper struct is used to ensure that GetCache() is called during
   // static initialization time, i.e. before any threads creation, as otherwise
   // the static s_cache construction inside GetCache() wouldn't be MT-safe
   friend struct wxStrCacheInitializer;
+#else // wxHAS_COMPILER_TLS
+  static wxTLS_TYPE(Cache) ms_cache;
+  static Cache& GetCache() { return wxTLS_VALUE(ms_cache); }
+#endif // !wxHAS_COMPILER_TLS/wxHAS_COMPILER_TLS
+
+  static Cache::Element *GetCacheBegin() { return GetCache().cached; }
+  static Cache::Element *GetCacheEnd() { return GetCacheBegin() + Cache::SIZE; }
+  static unsigned& LastUsedCacheElement() { return GetCache().lastUsed; }
 
   // this is used in debug builds only to provide a convenient function,
   // callable from a debugger, to show the cache contents
@@ -659,7 +671,15 @@ private:
       // profiling seems to show a small but consistent gain if we use this
       // simple loop instead of starting from the last used element (there are
       // a lot of misses in this function...)
-      for ( Cache::Element *c = GetCacheBegin(); c != GetCacheEnd(); c++ )
+      Cache::Element * const cacheBegin = GetCacheBegin();
+#ifndef wxHAS_COMPILER_TLS
+      // during destruction tls calls may return NULL, in this case return NULL 
+      // immediately without accessing anything else
+      if ( cacheBegin == NULL )
+        return NULL;
+#endif
+      Cache::Element * const cacheEnd = GetCacheEnd();
+      for ( Cache::Element *c = cacheBegin; c != cacheEnd; c++ )
       {
           if ( c->str == this )
               return c;
@@ -1438,12 +1458,7 @@ public:
     // truncate the string to given length
   wxString& Truncate(size_t uiLen);
     // empty string contents
-  void Empty()
-  {
-    Truncate(0);
-
-    wxASSERT_MSG( empty(), _T("string not empty after call to Empty()?") );
-  }
+  void Empty() { clear(); }
     // empty the string and free memory
   void Clear() { clear(); }