[clang] [lld] [llvm] [LTO][LLD] Prevent invalid LTO libfunc transforms (PR #164916)

[Daniel Thornburgh via cfe-commits]

================
@@ -51,6 +51,7 @@ add_llvm_component_library(LLVMObject
   BinaryFormat
   MCParser
   Support
+  Target
----------------
mysterymath wrote:

Alright, I've done so. The lastest commit moves isPreservedName out of IRSymtab and recasts it as isPreserved in LTO's Symbol. Users of this interface then directly ask about this rather than relying on IRSymtab to set isUsed in such cases. This seems much cleaner IMO; preservedness is a LTO thing, not an IR thing. That kills the FIXME and the new CMake dep.

https://github.com/llvm/llvm-project/pull/164916