[lld] [llvm] [lld] Add caching for `--lto-partitions` (PR #212203)

[Konstantin Belochapka via llvm-commits]

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@@ -547,12 +602,12 @@ static void splitCodeGen(const Config &C, TargetMachine *TM,
               std::unique_ptr<TargetMachine> TM =
                   createTargetMachine(C, T, *MPartInCtx);
 
-              codegen(C, TM.get(), AddStream, ThreadId, *MPartInCtx,
+              codegen(C, TM.get(), PartitionAddStream, ThreadId, *MPartInCtx,
                       CombinedIndex);
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kbelochapka wrote:

@Pierre-vh , `codegen()` arguments include `CombinedIndex`. Should the combined summary index be included in a cache entry hash calculation?

https://github.com/llvm/llvm-project/pull/212203