Mehdi Amini 3173b24456 ThinLTO: special handling for LinkOnce functions ... These function can be dropped by the compiler if they are no longer referenced in the current module. However there is a change that another module is still referencing them because of the import. Multiple solutions can be used: - Always import LinkOnce when a caller is imported. This ensure that every module with a call to a LinkOnce has the definition and will be able to emit it if it emits the call. - Turn the LinkOnce into Weak, so that it is always emitted. - Turn all LinkOnce into available_externally and come back after all modules are codegen'ed to emit only one copy of the linkonce, when there is still a reference to it. This patch implement the second option, with am optimization that only *one* module will turn the LinkOnce into Weak, while the others will turn it into available_externally, so that there is exactly one copy emitted for the whole compilation. http://reviews.llvm.org/D18346 From: Mehdi Amini <mehdi.amini@apple.com> llvm-svn: 265190		2016-04-01 21:53:50 +00:00
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X86	ThinLTO: special handling for LinkOnce functions	2016-04-01 21:53:50 +00:00