[llvm] [LLVM][Support] Add getTrailingObjects() for single trailing type (PR #138970)

[Rahul Joshi via llvm-commits]

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@@ -301,6 +302,41 @@ class TrailingObjects : private trailing_objects_internal::TrailingObjectsImpl<
         static_cast<BaseTy *>(this), TrailingObjectsBase::OverloadToken<T>());
   }
 
+  // getTrailingObjects() specialization for a single trailing type.
+  using FirstTrailingType =
+      typename std::tuple_element_t<0, std::tuple<TrailingTys...>>;
+
+  const FirstTrailingType *getTrailingObjects() const {
+    static_assert(sizeof...(TrailingTys) == 1,
+                  "Can use non-templated getTrailingObjects() only when there "
+                  "is a single trailing type");
+    return getTrailingObjects<FirstTrailingType>();
+  }
+
+  FirstTrailingType *getTrailingObjects() {
+    static_assert(sizeof...(TrailingTys) == 1,
+                  "Can use non-templated getTrailingObjects() only when there "
+                  "is a single trailing type");
+    return getTrailingObjects<FirstTrailingType>();
+  }
+
+  // Functions that return the trailing objects as ArrayRefs.
+  template <typename T> MutableArrayRef<T> getTrailingObjects(size_t N) {
+    return {getTrailingObjects<T>(), N};
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jurahul wrote:

`getTrailingObjects<T>()` returns a pointer to the heap allocated TrailingObject, so this is just wrapping up that heap pointer in an ArrayRef.

https://github.com/llvm/llvm-project/pull/138970