[llvm] [mlir] [utils][TableGen] Implement clause aliases as alternative spellings (PR #141765)

[Krzysztof Parzyszek via llvm-commits]

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@@ -109,7 +156,33 @@ class BaseRecord {
 public:
   BaseRecord(const Record *Def) : Def(Def) {}
 
-  StringRef getName() const { return Def->getValueAsString("name"); }
+  std::vector<Spelling::Value> getSpellings() const {
+    std::vector<Spelling::Value> List;
+    llvm::transform(Def->getValueAsListOfDefs("spellings"),
+                    std::back_inserter(List),
+                    [](const Record *R) { return Spelling(R).get(); });
+    return List;
+  }
+
+  StringRef getSpellingForIdentifier() const {
+    // From all spellings, pick the first one with the minimum version
+    // (i.e. pick the first from all the oldest ones). This guarantees
+    // that given several equivalent (in terms of versions) names, the
+    // first one is used, e.g. given
+    //   Clause<[Spelling<"foo">, Spelling<"bar">]> ...
+    // "foo" will be the selected spelling.
+    //
+    // This is a suitable spelling for generating an identifier name,
+    // since it will remain unchanged when any potential new spellings
+    // are added.
+    Spelling::Value Oldest{"not found", {/*Min=*/INT_MAX, 0}};
+    for (auto V : getSpellings()) {
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kparzysz wrote:

I removed it, but IMO {} make it more readable.

https://github.com/llvm/llvm-project/pull/141765