From 46d657a277f07233d0ee7a5522fc27d962922307 Mon Sep 17 00:00:00 2001
From: River Riddle <riverriddle@google.com>
Date: Mon, 27 May 2019 09:05:17 -0700
Subject: [PATCH]     Move the 'is_detected' utility out of StorageUniquer and
 into STLExtras to allow reuse throughout the codebase.

--

PiperOrigin-RevId: 250160508
---
 mlir/include/mlir/Support/STLExtras.h      | 21 ++++++++++++++
 mlir/include/mlir/Support/StorageUniquer.h | 44 +++++++++---------------------
 2 files changed, 34 insertions(+), 31 deletions(-)

diff --git a/mlir/include/mlir/Support/STLExtras.h b/mlir/include/mlir/Support/STLExtras.h
index b99b09d..c9a5198 100644
--- a/mlir/include/mlir/Support/STLExtras.h
+++ b/mlir/include/mlir/Support/STLExtras.h
@@ -84,6 +84,27 @@ struct alignas(8) ClassID {
     return &id;
   }
 };
+
+/// Utilities for detecting if a given trait holds for some set of arguments
+/// 'Args'. For example, the given trait could be used to detect if a given type
+/// has a copy assignment operator:
+///   template<class T>
+///   using has_copy_assign_t = decltype(std::declval<T&>()
+///                                                 = std::declval<const T&>());
+///   bool fooHasCopyAssign = is_detected<has_copy_assign_t, FooClass>::value;
+namespace detail {
+template <typename...> using void_t = void;
+template <class, template <class...> class Op, class... Args> struct detector {
+  using value_t = std::false_type;
+};
+template <template <class...> class Op, class... Args>
+struct detector<void_t<Op<Args...>>, Op, Args...> {
+  using value_t = std::true_type;
+};
+} // end namespace detail
+
+template <template <class...> class Op, class... Args>
+using is_detected = typename detail::detector<void, Op, Args...>::value_t;
 } // end namespace mlir
 
 // Allow tuples to be usable as DenseMap keys.
diff --git a/mlir/include/mlir/Support/StorageUniquer.h b/mlir/include/mlir/Support/StorageUniquer.h
index 3112a36..1873df1 100644
--- a/mlir/include/mlir/Support/StorageUniquer.h
+++ b/mlir/include/mlir/Support/StorageUniquer.h
@@ -18,13 +18,21 @@
 #ifndef MLIR_SUPPORT_STORAGEUNIQUER_H
 #define MLIR_SUPPORT_STORAGEUNIQUER_H
 
-#include "mlir/Support/LLVM.h"
+#include "mlir/Support/STLExtras.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
 
 namespace mlir {
 namespace detail {
 struct StorageUniquerImpl;
+
+/// Trait to check if ImplTy provides a 'getKey' method with types 'Args'.
+template <typename ImplTy, typename... Args>
+using has_impltype_getkey_t = decltype(ImplTy::getKey(std::declval<Args>()...));
+
+/// Trait to check if ImplTy provides a 'hashKey' method for 'T'.
+template <typename ImplTy, typename T>
+using has_impltype_hash_t = decltype(ImplTy::hashKey(std::declval<T>()));
 } // namespace detail
 
 /// A utility class to get, or create instances of storage classes. These
@@ -211,36 +219,14 @@ private:
   std::unique_ptr<detail::StorageUniquerImpl> impl;
 
   //===--------------------------------------------------------------------===//
-  // Util
-  //===--------------------------------------------------------------------===//
-
-  /// Utilities for detecting if specific traits hold for a given type 'T'.
-  template <typename...> using void_t = void;
-  template <class, template <class...> class Op, class... Args>
-  struct detector {
-    using value_t = std::false_type;
-  };
-  template <template <class...> class Op, class... Args>
-  struct detector<void_t<Op<Args...>>, Op, Args...> {
-    using value_t = std::true_type;
-  };
-  template <template <class...> class Op, class... Args>
-  using is_detected = typename detector<void, Op, Args...>::value_t;
-
-  //===--------------------------------------------------------------------===//
   // Key Construction
   //===--------------------------------------------------------------------===//
 
-  /// Trait to check if ImplTy provides a 'getKey' method with types 'Args'.
-  template <typename ImplTy, typename... Args>
-  using has_impltype_getkey_t =
-      decltype(ImplTy::getKey(std::declval<Args>()...));
-
   /// Used to construct an instance of 'ImplTy::KeyTy' if there is an
   /// 'ImplTy::getKey' function for the provided arguments.
   template <typename ImplTy, typename... Args>
   static typename std::enable_if<
-      is_detected<has_impltype_getkey_t, ImplTy, Args...>::value,
+      is_detected<detail::has_impltype_getkey_t, ImplTy, Args...>::value,
       typename ImplTy::KeyTy>::type
   getKey(Args &&... args) {
     return ImplTy::getKey(args...);
@@ -249,7 +235,7 @@ private:
   /// the 'ImplTy::KeyTy' with the provided arguments.
   template <typename ImplTy, typename... Args>
   static typename std::enable_if<
-      !is_detected<has_impltype_getkey_t, ImplTy, Args...>::value,
+      !is_detected<detail::has_impltype_getkey_t, ImplTy, Args...>::value,
       typename ImplTy::KeyTy>::type
   getKey(Args &&... args) {
     return typename ImplTy::KeyTy(args...);
@@ -259,15 +245,11 @@ private:
   // Key and Kind Hashing
   //===--------------------------------------------------------------------===//
 
-  /// Trait to check if ImplTy provides a 'hashKey' method for 'T'.
-  template <typename ImplTy, typename T>
-  using has_impltype_hash_t = decltype(ImplTy::hashKey(std::declval<T>()));
-
   /// Used to generate a hash for the 'ImplTy::KeyTy' and kind of a storage
   /// instance if there is an 'ImplTy::hashKey' overload for 'DerivedKey'.
   template <typename ImplTy, typename DerivedKey>
   static typename std::enable_if<
-      is_detected<has_impltype_hash_t, ImplTy, DerivedKey>::value,
+      is_detected<detail::has_impltype_hash_t, ImplTy, DerivedKey>::value,
       ::llvm::hash_code>::type
   getHash(unsigned kind, const DerivedKey &derivedKey) {
     return llvm::hash_combine(kind, ImplTy::hashKey(derivedKey));
@@ -276,7 +258,7 @@ private:
   /// 'llvm::DenseMapInfo' definition for 'DerivedKey' for generating a hash.
   template <typename ImplTy, typename DerivedKey>
   static typename std::enable_if<
-      !is_detected<has_impltype_hash_t, ImplTy, DerivedKey>::value,
+      !is_detected<detail::has_impltype_hash_t, ImplTy, DerivedKey>::value,
       ::llvm::hash_code>::type
   getHash(unsigned kind, const DerivedKey &derivedKey) {
     return llvm::hash_combine(
-- 
2.7.4