[clang] [WIP][clang] Fix std::tm etc. mangling on Solaris (PR #106353)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

The code assumes standard substitutions are not themselves substitutable.   So you probably need to call mangleSubstitution/addSubstitution explicitly in the code.  mangleSubstitution checks if there's an existing substitution, addSubstitution appends to the list of substitutions.  See https://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangling-compression .

Make sure you have a testcase with a function that takes two std::tm arguments.

https://github.com/llvm/llvm-project/pull/106353