[clang] [llvm] [NFC] [RISCV] Refactor class RISCVExtension (PR #120040)

[Pengcheng Wang via llvm-commits]

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@@ -22,11 +24,21 @@
 //             uses the record name by replacing Feature with Has.
 // value     - Value to assign to the field in RISCVSubtarget when this
 //             extension is enabled. Usually "true", but can be changed.
-class RISCVExtension<string name, int major, int minor, string desc,
+// IsExperimental
+//           - Indicates whether the extension is experimental
+class RISCVExtension<int major, int minor, string desc,
                      list<SubtargetFeature> implies = [],
                      string fieldname = !subst("Feature", "Has", NAME),
-                     string value = "true">
-    : SubtargetFeature<name, fieldname, value, desc, implies> {
+                     string value = "true", bit IsExperimental = false>
+    : SubtargetFeature<"", fieldname, value, "", implies> {
+  defvar ExtName = !subst("FeatureVendor", "", !subst("FeatureStdExt", "", NAME));
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wangpc-pp wrote:

I still think we should use lower case here. Please see also `SchedCommon` in `llvm/lib/Target/RISCV/RISCVInstrInfoV.td`.

We have the discussion before (but I forgot the patch), for local variables, we tend to use lower camel case.

https://github.com/llvm/llvm-project/pull/120040