Serialize the AST reader's mapping from canonical declarations to the
set of (previously-canonical) declaration IDs to the module file, so
that future AST reader instances that load the module know which
declarations are merged. This is important in the fairly tricky case
where a declaration of an entity, e.g.,

  @class X;

occurs before the import of a module that also declares that
entity. We merge the declarations, and record the fact that the
declaration of X loaded from the module was merged into the (now
canonical) declaration of X that we parsed.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147181 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed