Instead, define explicit specializations for the basic types listed in
the SGI documentation. This solves two problems:
1) Helps avoid silent ODR violations caused by the absence of a
user-supplied __gnu_cxx::hash specialization in cases where a std::hash
specialization exists (e.g. for std::string).
2) __gnu_cxx::hash semantics are slightly different to those of
std::hash (for example, the former may dereference a pointer argument)
so it is inappropriate for __gnu_cxx::hash to receive std::hash
specializations by default.
Differential Revision: http://llvm-reviews.chandlerc.com/D2747
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@203070 91177308-0d34-0410-b5e6-96231b3b80d8
are two motivations for this.
First, this allows users who are specializing __gnu_ext::hash to
continue doing so without changing their code.
Second, SGI specifies hash overloads for char* and const char* that
perform a hash of the string, not of the pointer.
In order to support this, the hashing code for string is factored out.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@136539 91177308-0d34-0410-b5e6-96231b3b80d8
