Temporarily revert r176116 for compile-time performance regression.

This reverts commit ea95e4587fd13606fbf63b10a07a7d02026aa39c.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176151 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclObjC.cpp b/lib/AST/DeclObjC.cpp
index d1bf9a9..d539e00 100644
--- a/lib/AST/DeclObjC.cpp
+++ b/lib/AST/DeclObjC.cpp
@@ -1093,51 +1093,38 @@
 /// all_declared_ivar_begin - return first ivar declared in this class,
 /// its extensions and its implementation. Lazily build the list on first
 /// access.
-///
-/// Caveat: The list returned by this method reflects the current
-/// state of the parser. The cache will be updated for every ivar
-/// added by an extension or the implementation when they are
-/// encountered.
-/// See also ObjCIvarDecl::Create().
 ObjCIvarDecl *ObjCInterfaceDecl::all_declared_ivar_begin() {
   // FIXME: Should make sure no callers ever do this.
   if (!hasDefinition())
     return 0;
   
+  if (data().IvarList)
+    return data().IvarList;
+  
   ObjCIvarDecl *curIvar = 0;
-  if (!data().IvarList) {
-    if (!ivar_empty()) {
-      ObjCInterfaceDecl::ivar_iterator I = ivar_begin(), E = ivar_end();
-      data().IvarList = *I; ++I;
-      for (curIvar = data().IvarList; I != E; curIvar = *I, ++I)
-        curIvar->setNextIvar(*I);
-    }
-
-    for (ObjCInterfaceDecl::known_extensions_iterator
-           Ext = known_extensions_begin(),
-           ExtEnd = known_extensions_end();
-         Ext != ExtEnd; ++Ext) {
-      if (!Ext->ivar_empty()) {
-        ObjCCategoryDecl::ivar_iterator
-          I = Ext->ivar_begin(),
-          E = Ext->ivar_end();
-        if (!data().IvarList) {
-          data().IvarList = *I; ++I;
-          curIvar = data().IvarList;
-        }
-        for ( ;I != E; curIvar = *I, ++I)
-          curIvar->setNextIvar(*I);
-      }
-    }
-    data().IvarListMissingImplementation = true;
+  if (!ivar_empty()) {
+    ObjCInterfaceDecl::ivar_iterator I = ivar_begin(), E = ivar_end();
+    data().IvarList = *I; ++I;
+    for (curIvar = data().IvarList; I != E; curIvar = *I, ++I)
+      curIvar->setNextIvar(*I);
   }
 
-  // cached and complete!
-  if (!data().IvarListMissingImplementation)
-      return data().IvarList;
+  for (ObjCInterfaceDecl::known_extensions_iterator
+         Ext = known_extensions_begin(),
+         ExtEnd = known_extensions_end();
+       Ext != ExtEnd; ++Ext) {
+    if (!Ext->ivar_empty()) {
+      ObjCCategoryDecl::ivar_iterator I = Ext->ivar_begin(),E = Ext->ivar_end();
+      if (!data().IvarList) {
+        data().IvarList = *I; ++I;
+        curIvar = data().IvarList;
+      }
+      for ( ;I != E; curIvar = *I, ++I)
+        curIvar->setNextIvar(*I);
+    }
+  }
   
   if (ObjCImplementationDecl *ImplDecl = getImplementation()) {
-    data().IvarListMissingImplementation = false;
     if (!ImplDecl->ivar_empty()) {
       SmallVector<SynthesizeIvarChunk, 16> layout;
       for (ObjCImplementationDecl::ivar_iterator I = ImplDecl->ivar_begin(),