Change ModuleLinker to take a set of GlobalValues to import instead of a single one

For efficiency reason, when importing multiple functions for the same Module,
we can avoid reparsing it every time.

Differential Revision: http://reviews.llvm.org/D15102

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254486 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed