[LTO] Turn ImportMapTy into a proper class (NFC) (#105748)

This patch turns type alias ImportMapTy into a proper class to provide
a more intuitive interface like:

  ImportList.addDefinition(...)

as opposed to:

  FunctionImporter::addDefinition(ImportList, ...)

Also, this patch requires all non-const accesses to go through
addDefinition, maybeAddDeclaration, and addGUID while providing const
accesses via:

  const ImportMapTyImpl &getImportMap() const { return ImportMap; }

I realize ImportMapTy may not be the best name as a class (maybe OK as
a type alias).  I am not renaming ImportMapTy in this patch at least
because there are 47 mentions of ImportMapTy under llvm/.

0 files changed, 0 insertions, 0 deletions