[clang] [llvm] Singleton hack of fixing static initialisation order ficaso (PR #154541)

[Eli Friedman via llvm-commits]

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@@ -160,7 +160,7 @@ inlineCostFeatureToMlFeature(InlineCostFeatureIndex Feature) {
   return static_cast<FeatureIndex>(static_cast<size_t>(Feature));
 }
 
-LLVM_ABI extern std::vector<TensorSpec> FeatureMap;
+LLVM_ABI extern std::vector<TensorSpec> &getFeatureMap();
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efriedma-quic wrote:

```suggestion
LLVM_ABI extern const std::vector<TensorSpec> &getFeatureMap();
```

https://github.com/llvm/llvm-project/pull/154541