Fixed the forward declaration issue that was present in the DWARF parser after
adding methods to C++ and objective C classes. In order to make methods, we
need the function prototype which means we need the arguments. Parsing these
could cause a circular reference that caused an  assertion.

Added a new typedef for the clang opaque types which are just void pointers:
lldb::clang_type_t. This appears in lldb-types.h.

This was fixed by enabling struct, union, class, and enum types to only get
a forward declaration when we make the clang opaque qual type for these
types. When they need to actually be resolved, lldb_private::Type will call
a new function in the SymbolFile protocol to resolve a clang type when it is
not fully defined (clang::TagDecl::getDefinition() returns NULL). This allows
us to be a lot more lazy when parsing clang types and keeps down the amount
of data that gets parsed into the ASTContext for each module. 

Getting the clang type from a "lldb_private::Type" object now takes a boolean
that indicates if a forward declaration is ok:

    clang_type_t lldb_private::Type::GetClangType (bool forward_decl_is_ok);
    
So function prototypes that define parameters that are "const T&" can now just
parse the forward declaration for type 'T' and we avoid circular references in
the type system.



git-svn-id: https://llvm.org/svn/llvm-project/llvdb/trunk@115012 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/source/Expression/ClangExpressionDeclMap.cpp b/source/Expression/ClangExpressionDeclMap.cpp
index d1d576f..43c4150 100644
--- a/source/Expression/ClangExpressionDeclMap.cpp
+++ b/source/Expression/ClangExpressionDeclMap.cpp
@@ -709,7 +709,7 @@
     
     if (type->GetASTContext() == var->GetType()->GetClangAST())
     {
-        if (!ClangASTContext::AreTypesSame(type->GetASTContext(), type->GetOpaqueQualType(), var->GetType()->GetOpaqueClangQualType()))
+        if (!ClangASTContext::AreTypesSame(type->GetASTContext(), type->GetOpaqueQualType(), var->GetType()->GetClangType()))
             return NULL;
     }
     else
@@ -759,7 +759,7 @@
         if (!this_type)
             return;
         
-        TypeFromUser this_user_type(this_type->GetOpaqueClangQualType(),
+        TypeFromUser this_user_type(this_type->GetClangType(),
                                     this_type->GetClangAST());
         
         m_object_pointer_type = this_user_type;
@@ -836,7 +836,7 @@
         
         if (type.get())
         {
-            TypeFromUser user_type(type->GetOpaqueClangQualType(),
+            TypeFromUser user_type(type->GetClangType(),
                                    type->GetClangAST());
             
             AddOneType(context, user_type, false);
@@ -866,7 +866,7 @@
         return NULL;
     }
     
-    void *var_opaque_type = var_type->GetOpaqueClangQualType();
+    void *var_opaque_type = var_type->GetClangType();
     
     if (!var_opaque_type)
     {
@@ -1043,7 +1043,7 @@
             return;
         }
         
-        fun_opaque_type = fun_type->GetOpaqueClangQualType();
+        fun_opaque_type = fun_type->GetClangType();
         
         if (!fun_opaque_type)
         {