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

[Matt Arsenault via cfe-commits]

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@@ -234,6 +234,10 @@ static cl::opt<bool>
     AllVtablesHaveTypeInfos("all-vtables-have-type-infos", cl::Hidden,
                             cl::desc("All vtables have type infos"));
 
+static cl::list<std::string>
+    BitcodeLibFuncs("bitcode-libfuncs", cl::Hidden,
+                    cl::desc("set of libfuncs implemented in bitcode"));
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arsenm wrote:

I've been thinking this should be a module flag, and we should have some scheme to indicate groups of functions from particular libraries, plus individual functions. Having to list every single symbol sounds unwieldy 

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