[10/N] Fixes clang-tidy warnings in c10/util/*.h (#116326)

Still a continued work for clean up c10/util/*.h
Pull Request resolved: https://github.com/pytorch/pytorch/pull/116326
Approved by: https://github.com/Skylion007

c10/util/AlignOf.h

@@ -35,6 +35,7 @@ namespace c10 {
 
 template <size_t Alignment, size_t Size>
 struct AlignedCharArray {
+  // NOLINTNEXTLINE(*c-arrays)
   alignas(Alignment) char buffer[Size];
 };
 
@@ -142,6 +143,7 @@ template <
     typename T9 = char,
     typename T10 = char>
 union SizerImpl {
+  // NOLINTNEXTLINE(*c-arrays)
   char arr1[sizeof(T1)], arr2[sizeof(T2)], arr3[sizeof(T3)], arr4[sizeof(T4)],
       arr5[sizeof(T5)], arr6[sizeof(T6)], arr7[sizeof(T7)], arr8[sizeof(T8)],
       arr9[sizeof(T9)], arr10[sizeof(T10)];

c10/util/Bitset.h

@@ -5,8 +5,7 @@
 #include <intrin.h>
 #endif
 
-namespace c10 {
+namespace c10::utils {
-namespace utils {
 
 /**
  * This is a simple bitset class with sizeof(long long int) bits.
@@ -114,5 +113,4 @@ inline bool operator!=(bitset lhs, bitset rhs) noexcept {
   return !(lhs == rhs);
 }
 
-} // namespace utils
+} // namespace c10::utils
-} // namespace c10

c10/util/CallOnce.h

@@ -47,7 +47,7 @@ class once_flag {
     if (init_.load(std::memory_order_relaxed)) {
       return;
     }
-    c10::guts::invoke(f, std::forward<Args>(args)...);
+    c10::guts::invoke(std::forward<F>(f), std::forward<Args>(args)...);
     init_.store(true, std::memory_order_release);
   }
 

c10/util/ExclusivelyOwnedTensorTraits.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <c10/core/TensorImpl.h>
+#include <c10/core/UndefinedTensorImpl.h>
 
 #include <utility>
 

c10/util/Float8_e4m3fn.cpp

@@ -1,10 +1,11 @@
 #include <c10/util/Float8_e4m3fn.h>
 #include <iostream>
+#include <type_traits>
 
 namespace c10 {
 
 static_assert(
-    std::is_standard_layout<Float8_e4m3fn>::value,
+    std::is_standard_layout_v<Float8_e4m3fn>,
     "c10::Float8_e4m3fn must be standard layout.");
 
 std::ostream& operator<<(std::ostream& out, const Float8_e4m3fn& value) {

c10/util/FunctionRef.h

@@ -50,14 +50,15 @@ class function_ref<Ret(Params...)> {
 
   template <typename Callable>
   function_ref(
+      // NOLINTNEXTLINE(cppcoreguidelines-missing-std-forward)
       Callable&& callable,
-      typename std::enable_if<!std::is_same<
+      std::enable_if_t<
-          typename std::remove_reference<Callable>::type,
+          !std::is_same_v<std::remove_reference_t<Callable>, function_ref>>* =
-          function_ref>::value>::type* = nullptr,
+          nullptr,
-      typename std::enable_if<std::is_convertible<
+      std::enable_if_t<std::is_convertible_v<
           typename std::invoke_result_t<Callable, Params...>,
-          Ret>::value>::type* = nullptr)
+          Ret>>* = nullptr)
-      : callback(callback_fn<typename std::remove_reference<Callable>::type>),
+      : callback(callback_fn<std::remove_reference_t<Callable>>),
         callable(reinterpret_cast<intptr_t>(&callable)) {}
 
   Ret operator()(Params... params) const {

c10/util/Metaprogramming.h

@@ -1,7 +1,6 @@
 #pragma once
 
 #include <c10/util/TypeList.h>
-#include <functional>
 #include <type_traits>
 
 namespace c10::guts {
@@ -207,6 +206,7 @@ constexpr auto tuple_slice(Tuple t) {
 namespace detail {
 template <class Mapper, class... Args, size_t... Indices>
 auto tuple_map(
+    // NOLINTNEXTLINE(cppcoreguidelines-rvalue-reference-param-not-moved)
     std::tuple<Args...>&& tuple,
     const Mapper& mapper,
     std::index_sequence<Indices...>) {

c10/util/SmallBuffer.h

@@ -1,5 +1,7 @@
 #pragma once
 #include <array>
+#include <cstddef>
+#include <cstdint>
 #include <type_traits>
 
 /** Helper class for allocating temporary fixed size arrays with SBO.
@@ -16,9 +18,7 @@ namespace c10 {
 
 template <typename T, size_t N>
 class SmallBuffer {
-  static_assert(
+  static_assert(std::is_trivial_v<T>, "SmallBuffer is intended for POD types");
-      std::is_trivial<T>::value,
-      "SmallBuffer is intended for POD types");
 
   std::array<T, N> storage_;
   size_t size_{};

c10/util/TypeList.h

@@ -201,7 +201,7 @@ struct all {
 };
 template <template <class> class Condition, class... Types>
 struct all<Condition, typelist<Types...>>
-    : guts::conjunction<Condition<Types>...> {
+    : std::conjunction<Condition<Types>...> {
   static_assert(
       is_type_condition<Condition>::value,
       "In typelist::all<Condition, TypeList>, the Condition argument must be a condition type trait, i.e. have a static constexpr bool ::value member.");
@@ -223,7 +223,7 @@ struct true_for_any_type final {
 };
 template <template <class> class Condition, class... Types>
 struct true_for_any_type<Condition, typelist<Types...>> final
-    : guts::disjunction<Condition<Types>...> {
+    : std::disjunction<Condition<Types>...> {
   static_assert(
       is_type_condition<Condition>::value,
       "In typelist::true_for_any_type<Condition, TypeList>, the Condition argument must be a condition type trait, i.e. have a static constexpr bool ::value member.");

c10/util/env.h

@@ -5,8 +5,7 @@
 #include <cstring>
 #include <optional>
 
-namespace c10 {
+namespace c10::utils {
-namespace utils {
 // Reads an environment variable and returns
 // - optional<true>,              if set equal to "1"
 // - optional<false>,             if set equal to "0"
@@ -39,5 +38,4 @@ inline std::optional<bool> check_env(const char* name) {
   }
   return std::nullopt;
 }
-} // namespace utils
+} // namespace c10::utils
-} // namespace c10

c10/util/floating_point_utils.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <c10/macros/Macros.h>
 #include <cstdint>
 
 namespace c10::detail {

c10/util/int128.h

@@ -33,6 +33,7 @@
 #pragma once
 
 #include <c10/macros/Export.h>
+#include <cstdint>
 #include <iosfwd>
 
 namespace c10 {

c10/util/overloaded.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <memory>
 namespace c10 {
 namespace detail {
 

c10/util/sparse_bitset.h

@@ -14,16 +14,12 @@
 #pragma once
 #include <c10/macros/Macros.h>
 #include <c10/util/llvmMathExtras.h>
+#include <array>
 #include <cassert>
 #include <climits>
-#include <cstring>
 #include <iterator>
 #include <list>
-
+#include <ostream>
-C10_CLANG_DIAGNOSTIC_PUSH()
-#if C10_CLANG_HAS_WARNING("-Wshorten-64-to-32")
-C10_CLANG_DIAGNOSTIC_IGNORE("-Wshorten-64-to-32")
-#endif
 
 namespace c10 {
 
@@ -54,18 +50,12 @@ struct SparseBitVectorElement {
  private:
   // Index of Element in terms of where first bit starts.
   unsigned ElementIndex;
-  BitWord Bits[BITWORDS_PER_ELEMENT];
+  std::array<BitWord, BITWORDS_PER_ELEMENT> Bits{};
 
-  SparseBitVectorElement() {
+  SparseBitVectorElement() : ElementIndex(~0U) {}
-    ElementIndex = ~0U;
-    memset(&Bits[0], 0, sizeof(BitWord) * BITWORDS_PER_ELEMENT);
-  }
 
  public:
-  explicit SparseBitVectorElement(unsigned Idx) {
+  explicit SparseBitVectorElement(unsigned Idx) : ElementIndex(Idx) {}
-    ElementIndex = Idx;
-    memset(&Bits[0], 0, sizeof(BitWord) * BITWORDS_PER_ELEMENT);
-  }
 
   // Comparison.
   bool operator==(const SparseBitVectorElement& RHS) const {
@@ -274,8 +264,10 @@ class SparseBitVector {
     // 'this' is always const in this particular function and we sort out the
     // difference in FindLowerBound and FindLowerBoundConst.
     ElementListIter Begin =
+        // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast)
         const_cast<SparseBitVector<ElementSize>*>(this)->Elements.begin();
     ElementListIter End =
+        // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast)
         const_cast<SparseBitVector<ElementSize>*>(this)->Elements.end();
 
     if (Elements.empty()) {
@@ -313,7 +305,7 @@ class SparseBitVector {
   // than it would be, in order to be efficient.
   class SparseBitVectorIterator {
    private:
-    bool AtEnd;
+    bool AtEnd{false};
 
     const SparseBitVector<ElementSize>* BitVector = nullptr;
 
@@ -321,13 +313,13 @@ class SparseBitVector {
     ElementListConstIter Iter;
 
     // Current bit number inside of our bitmap.
-    unsigned BitNumber;
+    unsigned BitNumber{0};
 
     // Current word number inside of our element.
-    unsigned WordNumber;
+    unsigned WordNumber{0};
 
     // Current bits from the element.
-    typename SparseBitVectorElement<ElementSize>::BitWord Bits;
+    typename SparseBitVectorElement<ElementSize>::BitWord Bits{0};
 
     // Move our iterator to the first non-zero bit in the bitmap.
     void AdvanceToFirstNonZero() {
@@ -392,12 +384,10 @@ class SparseBitVector {
     SparseBitVectorIterator(
         const SparseBitVector<ElementSize>* RHS,
         bool end = false)
-        : BitVector(RHS) {
+        : AtEnd(end),
-      Iter = BitVector->Elements.begin();
+          BitVector(RHS),
-      BitNumber = 0;
+          Iter(BitVector->Elements.begin()),
-      Bits = 0;
+          WordNumber(~0) {
-      WordNumber = ~0;
-      AtEnd = end;
       AdvanceToFirstNonZero();
     }
 
@@ -442,7 +432,7 @@ class SparseBitVector {
 
   SparseBitVector(const SparseBitVector& RHS)
       : Elements(RHS.Elements), CurrElementIter(Elements.begin()) {}
-  SparseBitVector(SparseBitVector&& RHS)
+  SparseBitVector(SparseBitVector&& RHS) noexcept
       : Elements(std::move(RHS.Elements)), CurrElementIter(Elements.begin()) {}
 
   // Clear.
@@ -459,7 +449,7 @@ class SparseBitVector {
     CurrElementIter = Elements.begin();
     return *this;
   }
-  SparseBitVector& operator=(SparseBitVector&& RHS) {
+  SparseBitVector& operator=(SparseBitVector&& RHS) noexcept {
     Elements = std::move(RHS.Elements);
     CurrElementIter = Elements.begin();
     return *this;
@@ -612,7 +602,7 @@ class SparseBitVector {
       if (Iter1->index() > Iter2->index()) {
         ++Iter2;
       } else if (Iter1->index() == Iter2->index()) {
-        bool BecameZero;
+        bool BecameZero = false;
         changed |= Iter1->intersectWith(*Iter2, BecameZero);
         if (BecameZero) {
           ElementListIter IterTmp = Iter1;
@@ -666,7 +656,7 @@ class SparseBitVector {
       if (Iter1->index() > Iter2->index()) {
         ++Iter2;
       } else if (Iter1->index() == Iter2->index()) {
-        bool BecameZero;
+        bool BecameZero = false;
         changed |= Iter1->intersectWithComplement(*Iter2, BecameZero);
         if (BecameZero) {
           ElementListIter IterTmp = Iter1;
@@ -900,5 +890,3 @@ std::ostream& operator<<(
 }
 
 } // end namespace c10
-
-C10_CLANG_DIAGNOSTIC_POP()

c10/util/ssize.h

@@ -38,6 +38,7 @@ constexpr auto ssize(const C& c) -> std::
 }
 
 template <typename T, std::ptrdiff_t N>
+// NOLINTNEXTLINE(*-c-arrays)
 constexpr auto ssize(const T (&array)[N]) noexcept -> std::ptrdiff_t {
   return N;
 }