[llvm] [llvm] Add format check for MCSubtargetFeatures (PR #180943)

[Georgiy Samoylov via llvm-commits]

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@@ -351,6 +351,31 @@ class Target {
   /// InstrumentManager, if registered (default = nullptr).
   InstrumentManagerCtorTy InstrumentManagerCtorFn = nullptr;
 
+  bool isValidFeatureListFormat(StringRef FeaturesString) const {
+    if (FeaturesString.empty())
+      return true;
+
+    llvm::SmallVector<llvm::StringRef, 8> Features;
+    FeaturesString.split(Features, ',', /*MaxSplit=*/-1, /*KeepEmpty=*/false);
+
+    if (Features.empty())
+      return false;
+
+    for (llvm::StringRef Feature : Features) {
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sga-sc wrote:

No, no at all

https://github.com/llvm/llvm-project/pull/180943