Extended Description

Compile the attachment with

clang++ -c repro.ii -fvisibility=hidden

then run nm -m repro.o.

gcc4.2 and clang prior to r156821 resulted in:

0000000000000000 (__DATA,__data) external __ZN18DeviceDataProviderI9RadioDataE17factory_function_E
(undefined) external __ZN18DeviceDataProviderI9RadioDataE22DefaultFactoryFunctionEv

clang with r156821 results in:

0000000000000000 (__DATA,__data) private external __ZN18DeviceDataProviderI9RadioDataE17factory_function_E
(undefined) external __ZN18DeviceDataProviderI9RadioDataE22DefaultFactoryFunctionEv

This breaks the chromium component build, target 'content_unittest' no longer links.

$ cat repro.ii

struct attribute((visibility("default"))) RadioData {};

class attribute((visibility("default"))) DeviceDataProviderImplBaseHack {};

template
class DeviceDataProviderImplBase : public DeviceDataProviderImplBaseHack {};

template
class DeviceDataProvider {
typedef DeviceDataProviderImplBase* (ImplFactoryFunction)(void);
attribute((visibility("default"))) static DeviceDataProviderImplBase DefaultFactoryFunction();
attribute((visibility("default"))) static ImplFactoryFunction factory_function_;
};

template<>
DeviceDataProvider::ImplFactoryFunction
DeviceDataProvider::factory_function_ = DefaultFactoryFunction;