Fix attaching to 32 bit inferior with 64 bit llgs.

[chaoren]

Summary

Executable module should use inferior architecture instead of host architecture.

[ovyalov]

lgtm

[clayborg]

Looks good.

lldb/trunk/source/Plugins/Process/Linux/NativeProcessLinux.cpp

namespace
     {
         // Grab process info for the running process.
         ProcessInstanceInfo process_info;
         if (!platform.GetProcessInfo (pid, process_info))
             return lldb_private::Error("failed to get process info");
 
         // Resolve the executable module.
         ModuleSP exe_module_sp;
-        ModuleSpec exe_module_spec(process_info.GetExecutableFile(), platform.GetSystemArchitecture ());
+        ModuleSpec exe_module_spec(process_info.GetExecutableFile(), process_info.GetArchitecture());
         FileSpecList executable_search_paths (Target::GetDefaultExecutableSearchPaths ());
         Error error = platform.ResolveExecutable(
             exe_module_spec,
             exe_module_sp,
             executable_search_paths.GetSize () ? &executable_search_paths : NULL);
 
         if (!error.Success ())
             return error;
if (!platform_sp->GetProcessInfo (pid, process_info))
             log->Printf ("NativeProcessLinux::%s (pid = %" PRIi64 "): failed to get process info", __FUNCTION__, pid);
         error.SetErrorString ("failed to get process info");
         return;
     }
 
     // Resolve the executable module
     ModuleSP exe_module_sp;
     FileSpecList executable_search_paths (Target::GetDefaultExecutableSearchPaths());
-    ModuleSpec exe_module_spec(process_info.GetExecutableFile(), HostInfo::GetArchitecture());
+    ModuleSpec exe_module_spec(process_info.GetExecutableFile(), process_info.GetArchitecture());
     error = platform_sp->ResolveExecutable(exe_module_spec, exe_module_sp,
                                            executable_search_paths.GetSize() ? &executable_search_paths : NULL);
     if (!error.Success())
         return;
 
     // Set the architecture to the exe architecture.
     m_arch = exe_module_sp->GetArchitecture();
     if (log)