Before, everything was based on some kind of type erased parser
implementation which container a lot of boilerplate code when multiple
formats were to be supported.
This simplifies it by:
* the remark now owns its arguments
* *always* returning an error from the implementation side
* working around the way the YAML parser reports errors: catch them through
callbacks and re-insert them in a proper llvm::Error
* add a CParser wrapper that is used when implementing the C API to
avoid cluttering the C++ API with useless state
* LLVMRemarkParserGetNext now returns an object that needs to be
released to avoid leaking resources
* add a new API to dispose of a remark entry: LLVMRemarkEntryDispose
llvm-svn: 366217
94bad22c2c