Specialization for `c10::util:get_type_index<std::string>` (#66290)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66290
Add full specialization for std::string type index
It slightly speeds up compilation as well as solves the ambiguity how template instantiations implemented in inline namespaces are rendered during `__PRETTY_FUNCTION__` computation.
Not sure what `#pragma` controls this behaviour, but when code is compiled by clang-12+ using libstdc++, `__PRETTY_PRINT__`, sometimes resolve `std::string` to `std::basic_string<char>` and sometimes to `std::__cxx11::basic_string<char>`, even though in the object file symbol is always inside `std::__cxx11::` namespace, which might break caffe2 serialization code that depends on dynamic hash generation
Template name resolution were debugged using https://gist.github.com/malfet/c83b9ebd35730ebf8bac7af42682ea37
(Note: this ignores all push blocking failures!)
Test Plan: CI
Reviewed By: r-barnes
Differential Revision: D31490050
fbshipit-source-id: 127091574cf6b92c7ec3f972821e4e76f5f626a9
