<rdar://problem/10103468>

I started work on being able to add symbol files after a debug session
had started with a new "target symfile add" command and quickly ran into
problems with stale Address objects in breakpoint locations that had 
lldb_private::Section pointers into modules that had been removed or 
replaced. This also let to grabbing stale modules from those sections. 
So I needed to thread harded the Address, Section and related objects.

To do this I modified the ModuleChild class to now require a ModuleSP
on initialization so that a weak reference can created. I also changed
all places that were handing out "Section *" to have them hand out SectionSP.
All ObjectFile, SymbolFile and SymbolVendors were inheriting from ModuleChild
so all of the find plug-in, static creation function and constructors now
require ModuleSP references instead of Module *. 

Address objects now have weak references to their sections which can
safely go stale when a module gets destructed. 

This checkin doesn't complete the "target symfile add" command, but it
does get us a lot clioser to being able to do such things without a high
risk of crashing or memory corruption.

llvm-svn: 151336
diff --git a/lldb/source/Target/SectionLoadList.cpp b/lldb/source/Target/SectionLoadList.cpp
index df28023..05a97a2 100644
--- a/lldb/source/Target/SectionLoadList.cpp
+++ b/lldb/source/Target/SectionLoadList.cpp
@@ -94,15 +94,15 @@
     {
         if (section != ats_pos->second)
         {
-            Module *module = section->GetModule();
-            if (module)
+            ModuleSP module_sp (section->GetModule());
+            if (module_sp)
             {
-                module->ReportWarning ("address 0x%16.16llx maps to more than one section: %s.%s and %s.%s",
-                                       load_addr, 
-                                       module->GetFileSpec().GetFilename().GetCString(), 
-                                       section->GetName().GetCString(),
-                                       ats_pos->second->GetModule()->GetFileSpec().GetFilename().GetCString(), 
-                                       ats_pos->second->GetName().GetCString());
+                module_sp->ReportWarning ("address 0x%16.16llx maps to more than one section: %s.%s and %s.%s",
+                                          load_addr, 
+                                          module_sp->GetFileSpec().GetFilename().GetCString(), 
+                                          section->GetName().GetCString(),
+                                          ats_pos->second->GetModule()->GetFileSpec().GetFilename().GetCString(), 
+                                          ats_pos->second->GetName().GetCString());
             }
         }
         ats_pos->second = section;