[llvm-branch-commits] [llvm] 557b00e - Delete llvm::is_trivially_copyable and CMake variable HAVE_STD_IS_TRIVIALLY_COPYABLE

Fangrui Song via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Wed Dec 2 10:02:45 PST 2020


Author: Fangrui Song
Date: 2020-12-02T09:58:08-08:00
New Revision: 557b00e0afb2dc1776f50948094ca8cc62d97be4

URL: https://github.com/llvm/llvm-project/commit/557b00e0afb2dc1776f50948094ca8cc62d97be4
DIFF: https://github.com/llvm/llvm-project/commit/557b00e0afb2dc1776f50948094ca8cc62d97be4.diff

LOG: Delete llvm::is_trivially_copyable and CMake variable HAVE_STD_IS_TRIVIALLY_COPYABLE

GCC<5 did not support std::is_trivially_copyable. Now LLVM builds
require 5.1 we can delete llvm::is_trivially_copyable after the users
have been migrated to std::is_trivially_copyable.

Added: 
    

Modified: 
    llvm/cmake/config-ix.cmake
    llvm/include/llvm/ADT/PointerIntPair.h
    llvm/include/llvm/Config/config.h.cmake
    llvm/include/llvm/Support/type_traits.h
    llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

Removed: 
    


################################################################################
diff  --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
index 818fafbce148..b4c54da01912 100644
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -351,15 +351,6 @@ else()
   unset(HAVE_FFI_CALL CACHE)
 endif( LLVM_ENABLE_FFI )
 
-# Whether we can use std::is_trivially_copyable to verify llvm::is_trivially_copyable.
-CHECK_CXX_SOURCE_COMPILES("
-#include <type_traits>
-struct T { int val; };
-static_assert(std::is_trivially_copyable<T>::value, \"ok\");
-int main() { return 0;}
-" HAVE_STD_IS_TRIVIALLY_COPYABLE)
-
-
 # Define LLVM_HAS_ATOMICS if gcc or MSVC atomic builtins are supported.
 include(CheckAtomic)
 

diff  --git a/llvm/include/llvm/ADT/PointerIntPair.h b/llvm/include/llvm/ADT/PointerIntPair.h
index cb8b202c48b7..600fcebff3ea 100644
--- a/llvm/include/llvm/ADT/PointerIntPair.h
+++ b/llvm/include/llvm/ADT/PointerIntPair.h
@@ -15,7 +15,6 @@
 
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/PointerLikeTypeTraits.h"
-#include "llvm/Support/type_traits.h"
 #include <cassert>
 #include <cstdint>
 #include <limits>
@@ -127,19 +126,6 @@ class PointerIntPair {
   }
 };
 
-// Specialize is_trivially_copyable to avoid limitation of llvm::is_trivially_copyable
-// when compiled with gcc 4.9.
-template <typename PointerTy, unsigned IntBits, typename IntType,
-          typename PtrTraits,
-          typename Info>
-struct is_trivially_copyable<PointerIntPair<PointerTy, IntBits, IntType, PtrTraits, Info>> : std::true_type {
-#ifdef HAVE_STD_IS_TRIVIALLY_COPYABLE
-  static_assert(std::is_trivially_copyable<PointerIntPair<PointerTy, IntBits, IntType, PtrTraits, Info>>::value,
-                "inconsistent behavior between llvm:: and std:: implementation of is_trivially_copyable");
-#endif
-};
-
-
 template <typename PointerT, unsigned IntBits, typename PtrTraits>
 struct PointerIntPairInfo {
   static_assert(PtrTraits::NumLowBitsAvailable <

diff  --git a/llvm/include/llvm/Config/config.h.cmake b/llvm/include/llvm/Config/config.h.cmake
index 6664ad335584..4da1d199db67 100644
--- a/llvm/include/llvm/Config/config.h.cmake
+++ b/llvm/include/llvm/Config/config.h.cmake
@@ -332,9 +332,6 @@
 /* Define as the return type of signal handlers (`int' or `void'). */
 #cmakedefine RETSIGTYPE ${RETSIGTYPE}
 
-/* Define if std::is_trivially_copyable is supported */
-#cmakedefine HAVE_STD_IS_TRIVIALLY_COPYABLE ${HAVE_STD_IS_TRIVIALLY_COPYABLE}
-
 /* Define to a function implementing stricmp */
 #cmakedefine stricmp ${stricmp}
 

diff  --git a/llvm/include/llvm/Support/type_traits.h b/llvm/include/llvm/Support/type_traits.h
index 7b7d5d991f3f..383f087f4bc2 100644
--- a/llvm/include/llvm/Support/type_traits.h
+++ b/llvm/include/llvm/Support/type_traits.h
@@ -85,11 +85,6 @@ template<typename T> union move_construction_triviality_helper {
     ~move_construction_triviality_helper() = default;
 };
 
-template<class T>
-union trivial_helper {
-    T t;
-};
-
 } // end namespace detail
 
 /// An implementation of `std::is_trivially_copy_constructible` since we have
@@ -114,78 +109,6 @@ struct is_trivially_move_constructible<T &> : std::true_type {};
 template <typename T>
 struct is_trivially_move_constructible<T &&> : std::true_type {};
 
-
-template <typename T>
-struct is_copy_assignable {
-  template<class F>
-    static auto get(F*) -> decltype(std::declval<F &>() = std::declval<const F &>(), std::true_type{});
-    static std::false_type get(...);
-    static constexpr bool value = decltype(get((T*)nullptr))::value;
-};
-
-template <typename T>
-struct is_move_assignable {
-  template<class F>
-    static auto get(F*) -> decltype(std::declval<F &>() = std::declval<F &&>(), std::true_type{});
-    static std::false_type get(...);
-    static constexpr bool value = decltype(get((T*)nullptr))::value;
-};
-
-
-// An implementation of `std::is_trivially_copyable` since STL version
-// is not equally supported by all compilers, especially GCC 4.9.
-// Uniform implementation of this trait is important for ABI compatibility
-// as it has an impact on SmallVector's ABI (among others).
-template <typename T>
-class is_trivially_copyable {
-
-  // copy constructors
-  static constexpr bool has_trivial_copy_constructor =
-      std::is_copy_constructible<detail::trivial_helper<T>>::value;
-  static constexpr bool has_deleted_copy_constructor =
-      !std::is_copy_constructible<T>::value;
-
-  // move constructors
-  static constexpr bool has_trivial_move_constructor =
-      std::is_move_constructible<detail::trivial_helper<T>>::value;
-  static constexpr bool has_deleted_move_constructor =
-      !std::is_move_constructible<T>::value;
-
-  // copy assign
-  static constexpr bool has_trivial_copy_assign =
-      is_copy_assignable<detail::trivial_helper<T>>::value;
-  static constexpr bool has_deleted_copy_assign =
-      !is_copy_assignable<T>::value;
-
-  // move assign
-  static constexpr bool has_trivial_move_assign =
-      is_move_assignable<detail::trivial_helper<T>>::value;
-  static constexpr bool has_deleted_move_assign =
-      !is_move_assignable<T>::value;
-
-  // destructor
-  static constexpr bool has_trivial_destructor =
-      std::is_destructible<detail::trivial_helper<T>>::value;
-
-  public:
-
-  static constexpr bool value =
-      has_trivial_destructor &&
-      (has_deleted_move_assign || has_trivial_move_assign) &&
-      (has_deleted_move_constructor || has_trivial_move_constructor) &&
-      (has_deleted_copy_assign || has_trivial_copy_assign) &&
-      (has_deleted_copy_constructor || has_trivial_copy_constructor);
-
-#ifdef HAVE_STD_IS_TRIVIALLY_COPYABLE
-  static_assert(value == std::is_trivially_copyable<T>::value,
-                "inconsistent behavior between llvm:: and std:: implementation of is_trivially_copyable");
-#endif
-};
-template <typename T>
-class is_trivially_copyable<T*> : public std::true_type {
-};
-
-
 } // end namespace llvm
 
 #endif // LLVM_SUPPORT_TYPE_TRAITS_H

diff  --git a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
index 389d5e962bc9..193a59490560 100644
--- a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
@@ -89,7 +89,6 @@ write_cmake_config("config") {
     "HAVE_LIBPSAPI=",
     "HAVE_MALLCTL=",
     "HAVE_SIGNAL_H=1",
-    "HAVE_STD_IS_TRIVIALLY_COPYABLE=1",
     "HAVE_STRERROR=1",
     "HAVE_SYS_STAT_H=1",
     "HAVE_SYS_TYPES_H=1",


        


More information about the llvm-branch-commits mailing list