[clang] [llvm] Support VFE in thinLTO (PR #69735)

[Teresa Johnson via cfe-commits]

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@@ -1362,6 +1362,8 @@ class ModuleSummaryIndex {
   // Temporary map while building StackIds list. Clear when index is completely
   // built via releaseTemporaryMemory.
   std::map<uint64_t, unsigned> StackIdToIndex;
+  std::set<GlobalValue::GUID> FuncsWithNonVtableRef;
+  std::set<GlobalValue::GUID> VFuncsToBeRemoved; // no need to serialize
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teresajohnson wrote:

It would need to be serialized for distributed thinlto. A better thing would be to describe which of these are produced by the per-module analysis and used by the thin link, vs produced by the thin link and consumed by the ThinLTO backends. However, I suggest making these flags as noted above (but those should be documented with this information too)

https://github.com/llvm/llvm-project/pull/69735