[lld] [llvm] [DTLTO] Improve performance of adding files to the link (PR #186366)

[Teresa Johnson via llvm-commits]

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@@ -2742,7 +2748,11 @@ class OutOfProcessThinBackend : public CGThinBackend {
           *(CacheStream.OS) << ObjFileMbRef.getBuffer();
           if (Error Err = CacheStream.commit())
             return Err;
+        } else if (AddBuffer) {
+          AddBuffer(Job.Task, Job.ModuleID, std::move(*ObjFileMbOrErr));
         } else {
+          MemoryBufferRef ObjFileMbRef =
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teresajohnson wrote:

If AddBuffer is made mandatory, can this fallback be removed?

https://github.com/llvm/llvm-project/pull/186366