[libc++] Pass type information down to __libcpp_allocate

libcxx/include/CMakeLists.txt

@@ -547,7 +547,6 @@ set(files
   __memory/array_cookie.h
   __memory/assume_aligned.h
   __memory/auto_ptr.h
-  __memory/builtin_new_allocator.h
   __memory/compressed_pair.h
   __memory/concepts.h
   __memory/construct_at.h
@@ -880,6 +879,7 @@ set(files
   __utility/cmp.h
   __utility/convert_to_integral.h
   __utility/declval.h
+  __utility/element_count.h
   __utility/empty.h
   __utility/exception_guard.h
   __utility/exchange.h

libcxx/include/__functional/function.h

@@ -22,7 +22,6 @@
 #include <__memory/allocator.h>
 #include <__memory/allocator_destructor.h>
 #include <__memory/allocator_traits.h>
-#include <__memory/builtin_new_allocator.h>
 #include <__memory/compressed_pair.h>
 #include <__memory/unique_ptr.h>
 #include <__type_traits/aligned_storage.h>
@@ -193,6 +192,13 @@ class __alloc_func<_Fp, _Ap, _Rp(_ArgTypes...)> {
   }
 };
 
+template <class _Tp>
+struct __deallocating_deleter {
+  _LIBCPP_HIDE_FROM_ABI void operator()(void* __p) const {
+    std::__libcpp_deallocate<_Tp>(static_cast<_Tp*>(__p), __element_count(1));
+  }
+};
+
 template <class _Fp, class _Rp, class... _ArgTypes>
 class __default_alloc_func<_Fp, _Rp(_ArgTypes...)> {
   _Fp __f_;
@@ -212,8 +218,9 @@ class __default_alloc_func<_Fp, _Rp(_ArgTypes...)> {
   }
 
   _LIBCPP_HIDE_FROM_ABI __default_alloc_func* __clone() const {
-    __builtin_new_allocator::__holder_t __hold = __builtin_new_allocator::__allocate_type<__default_alloc_func>(1);
-    __default_alloc_func* __res                = ::new ((void*)__hold.get()) __default_alloc_func(__f_);
+    using _Self = __default_alloc_func;
+    unique_ptr<_Self, __deallocating_deleter<_Self>> __hold(std::__libcpp_allocate<_Self>(__element_count(1)));
+    _Self* __res = ::new ((void*)__hold.get()) _Self(__f_);
     (void)__hold.release();
     return __res;
   }
@@ -222,7 +229,7 @@ class __default_alloc_func<_Fp, _Rp(_ArgTypes...)> {
 
   _LIBCPP_HIDE_FROM_ABI static void __destroy_and_delete(__default_alloc_func* __f) {
     __f->destroy();
-    __builtin_new_allocator::__deallocate_type<__default_alloc_func>(__f, 1);
+    std::__libcpp_deallocate<__default_alloc_func>(__f, __element_count(1));
   }
 };
 
@@ -668,8 +675,8 @@ class __policy_func<_Rp(_ArgTypes...)> {
       if (__use_small_storage<_Fun>()) {
         ::new ((void*)&__buf_.__small) _Fun(std::move(__f));
       } else {
-        __builtin_new_allocator::__holder_t __hold = __builtin_new_allocator::__allocate_type<_Fun>(1);
-        __buf_.__large                             = ::new ((void*)__hold.get()) _Fun(std::move(__f));
+        unique_ptr<_Fun, __deallocating_deleter<_Fun>> __hold(std::__libcpp_allocate<_Fun>(__element_count(1)));
+        __buf_.__large = ::new ((void*)__hold.get()) _Fun(std::move(__f));
         (void)__hold.release();
       }
     }

libcxx/include/__memory/allocator.h

@@ -102,7 +102,7 @@ class _LIBCPP_TEMPLATE_VIS allocator : private __non_trivial_if<!is_void<_Tp>::v
     if (__libcpp_is_constant_evaluated()) {
       return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
     } else {
-      return static_cast<_Tp*>(std::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)));
+      return std::__libcpp_allocate<_Tp>(__element_count(__n));
     }
   }
 
@@ -117,7 +117,7 @@ class _LIBCPP_TEMPLATE_VIS allocator : private __non_trivial_if<!is_void<_Tp>::v
     if (__libcpp_is_constant_evaluated()) {
       ::operator delete(__p);
     } else {
-      std::__libcpp_deallocate((void*)__p, __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));
+      std::__libcpp_deallocate<_Tp>(__p, __element_count(__n));
     }
   }
 

libcxx/include/__memory/unique_temporary_buffer.h

@@ -40,7 +40,7 @@ struct __temporary_buffer_deleter {
       return;
     }
 
-    std::__libcpp_deallocate_unsized((void*)__ptr, _LIBCPP_ALIGNOF(_Tp));
+    std::__libcpp_deallocate_unsized<_Tp>(__ptr);
   }
 };
 

libcxx/include/__new/allocate.h

@@ -14,6 +14,8 @@
 #include <__cstddef/size_t.h>
 #include <__new/align_val_t.h>
 #include <__new/global_new_delete.h> // for _LIBCPP_HAS_SIZED_DEALLOCATION
+#include <__type_traits/type_identity.h>
+#include <__utility/element_count.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -47,52 +49,58 @@ _LIBCPP_HIDE_FROM_ABI void __libcpp_operator_delete(_Args... __args) _NOEXCEPT {
 #endif
 }
 
-inline _LIBCPP_HIDE_FROM_ABI void* __libcpp_allocate(size_t __size, size_t __align) {
+template <class _Tp>
+inline _LIBCPP_HIDE_FROM_ABI _Tp* __libcpp_allocate(__element_count __n, size_t __align = _LIBCPP_ALIGNOF(_Tp)) {
+  size_t __size = static_cast<size_t>(__n) * sizeof(_Tp);
 #if _LIBCPP_HAS_ALIGNED_ALLOCATION
   if (__is_overaligned_for_new(__align)) {
     const align_val_t __align_val = static_cast<align_val_t>(__align);
-    return __libcpp_operator_new(__size, __align_val);
+    return static_cast<_Tp*>(std::__libcpp_operator_new(__size, __align_val));
   }
 #endif
 
   (void)__align;
-  return __libcpp_operator_new(__size);
+  return static_cast<_Tp*>(std::__libcpp_operator_new(__size));
 }
 
-template <class... _Args>
-_LIBCPP_HIDE_FROM_ABI void __do_deallocate_handle_size(void* __ptr, size_t __size, _Args... __args) _NOEXCEPT {
-#if !_LIBCPP_HAS_SIZED_DEALLOCATION
-  (void)__size;
-  return std::__libcpp_operator_delete(__ptr, __args...);
+#if _LIBCPP_HAS_SIZED_DEALLOCATION
+#  define _LIBCPP_ONLY_IF_SIZED_DEALLOCATION(...) __VA_ARGS__
 #else
-  return std::__libcpp_operator_delete(__ptr, __size, __args...);
+#  define _LIBCPP_ONLY_IF_SIZED_DEALLOCATION(...) /* nothing */
 #endif
-}
 
-inline _LIBCPP_HIDE_FROM_ABI void __libcpp_deallocate(void* __ptr, size_t __size, size_t __align) _NOEXCEPT {
+template <class _Tp>
+inline _LIBCPP_HIDE_FROM_ABI void __libcpp_deallocate(
+    __type_identity_t<_Tp>* __ptr, __element_count __n, size_t __align = _LIBCPP_ALIGNOF(_Tp)) _NOEXCEPT {
+  size_t __size = static_cast<size_t>(__n) * sizeof(_Tp);
+  (void)__size;
 #if !_LIBCPP_HAS_ALIGNED_ALLOCATION
   (void)__align;
-  return __do_deallocate_handle_size(__ptr, __size);
+  return std::__libcpp_operator_delete(__ptr _LIBCPP_ONLY_IF_SIZED_DEALLOCATION(, __size));
 #else
   if (__is_overaligned_for_new(__align)) {
     const align_val_t __align_val = static_cast<align_val_t>(__align);
-    return __do_deallocate_handle_size(__ptr, __size, __align_val);
+    return std::__libcpp_operator_delete(__ptr _LIBCPP_ONLY_IF_SIZED_DEALLOCATION(, __size), __align_val);
   } else {
-    return __do_deallocate_handle_size(__ptr, __size);
+    return std::__libcpp_operator_delete(__ptr _LIBCPP_ONLY_IF_SIZED_DEALLOCATION(, __size));
   }
 #endif
 }
 
-inline _LIBCPP_HIDE_FROM_ABI void __libcpp_deallocate_unsized(void* __ptr, size_t __align) _NOEXCEPT {
+#undef _LIBCPP_ONLY_IF_SIZED_DEALLOCATION
+
+template <class _Tp>
+inline _LIBCPP_HIDE_FROM_ABI void
+__libcpp_deallocate_unsized(__type_identity_t<_Tp>* __ptr, size_t __align = _LIBCPP_ALIGNOF(_Tp)) _NOEXCEPT {
 #if !_LIBCPP_HAS_ALIGNED_ALLOCATION
   (void)__align;
-  return __libcpp_operator_delete(__ptr);
+  return std::__libcpp_operator_delete(__ptr);
 #else
   if (__is_overaligned_for_new(__align)) {
     const align_val_t __align_val = static_cast<align_val_t>(__align);
-    return __libcpp_operator_delete(__ptr, __align_val);
+    return std::__libcpp_operator_delete(__ptr, __align_val);
   } else {
-    return __libcpp_operator_delete(__ptr);
+    return std::__libcpp_operator_delete(__ptr);
   }
 #endif
 }

libcxx/include/__string/constexpr_c_functions.h

@@ -25,6 +25,7 @@
 #include <__type_traits/is_trivially_copyable.h>
 #include <__type_traits/is_trivially_lexicographically_comparable.h>
 #include <__type_traits/remove_cv.h>
+#include <__utility/element_count.h>
 #include <__utility/is_pointer_in_range.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -33,10 +34,6 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-// Type used to encode that a function takes an integer that represents a number
-// of elements as opposed to a number of bytes.
-enum class __element_count : size_t {};
-
 template <class _Tp>
 inline const bool __is_char_type = false;
 

libcxx/include/__utility/element_count.h

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_ELEMENT_COUNT_H
+#define _LIBCPP___UTILITY_ELEMENT_COUNT_H
+
+#include <__config>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Type used to encode that a function takes an integer that represents a number
+// of elements as opposed to a number of bytes.
+enum class __element_count : size_t {};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_ELEMENT_COUNT_H

libcxx/include/__utility/small_buffer.h

@@ -68,7 +68,7 @@ class __small_buffer {
     if constexpr (__fits_in_buffer<_Stored>) {
       return std::launder(reinterpret_cast<_Stored*>(__buffer_));
     } else {
-      byte* __allocation = static_cast<byte*>(std::__libcpp_allocate(sizeof(_Stored), alignof(_Stored)));
+      byte* __allocation = static_cast<byte*>(std::__libcpp_allocate<_Stored>(__element_count(1)));
       std::construct_at(reinterpret_cast<byte**>(__buffer_), __allocation);
       return std::launder(reinterpret_cast<_Stored*>(__allocation));
     }
@@ -77,7 +77,7 @@ class __small_buffer {
   template <class _Stored>
   _LIBCPP_HIDE_FROM_ABI void __dealloc() noexcept {
     if constexpr (!__fits_in_buffer<_Stored>)
-      std::__libcpp_deallocate(*reinterpret_cast<void**>(__buffer_), sizeof(_Stored), alignof(_Stored));
+      std::__libcpp_deallocate<_Stored>(__get<_Stored>(), __element_count(1));
   }
 
   template <class _Stored, class... _Args>

libcxx/include/module.modulemap

@@ -1525,14 +1525,16 @@ module std [system] {
     module aligned_alloc                      { header "__memory/aligned_alloc.h" }
     module allocate_at_least                  { header "__memory/allocate_at_least.h" }
     module allocation_guard                   { header "__memory/allocation_guard.h" }
-    module allocator                          { header "__memory/allocator.h" }
+    module allocator {
+      header "__memory/allocator.h"
+      export * // TODO: Workaround for https://github.com/llvm/llvm-project/issues/120108
+    }
     module allocator_arg_t                    { header "__memory/allocator_arg_t.h" }
     module allocator_destructor               { header "__memory/allocator_destructor.h" }
     module allocator_traits                   { header "__memory/allocator_traits.h" }
     module array_cookie                       { header "__memory/array_cookie.h" }
     module assume_aligned                     { header "__memory/assume_aligned.h" }
     module auto_ptr                           { header "__memory/auto_ptr.h" }
-    module builtin_new_allocator              { header "__memory/builtin_new_allocator.h" }
     module compressed_pair                    { header "__memory/compressed_pair.h" }
     module concepts                           { header "__memory/concepts.h" }
     module construct_at                       { header "__memory/construct_at.h" }
@@ -1567,6 +1569,7 @@ module std [system] {
       header "__memory/unique_temporary_buffer.h"
       export std.memory.unique_ptr
       export std_core.type_traits.is_constant_evaluated
+      export * // TODO: Workaround for https://github.com/llvm/llvm-project/issues/120108
     }
     module uses_allocator                     { header "__memory/uses_allocator.h" }
     module uses_allocator_construction        { header "__memory/uses_allocator_construction.h" }
@@ -1602,7 +1605,11 @@ module std [system] {
   module new {
     header "new"
     module align_val_t          { header "__new/align_val_t.h" }
-    module allocate             { header "__new/allocate.h" }
+    module allocate {
+      header "__new/allocate.h"
+      export std.utility.element_count // used as part of the API
+      export * // TODO: Workaround for https://github.com/llvm/llvm-project/issues/120108
+    }
     module destroying_delete_t  { header "__new/destroying_delete_t.h" }
     module exceptions           { header "__new/exceptions.h" }
     module global_new_delete    {
@@ -1909,7 +1916,10 @@ module std [system] {
 
   module string {
     module char_traits              { header "__string/char_traits.h" }
-    module constexpr_c_functions    { header "__string/constexpr_c_functions.h" }
+    module constexpr_c_functions    {
+      header "__string/constexpr_c_functions.h"
+      export std.utility.element_count // used as part of the constexpr C function's API
+    }
     module extern_template_lists    { header "__string/extern_template_lists.h" }
     module fwd                      {  header "__fwd/string.h" }
 
@@ -2019,6 +2029,7 @@ module std [system] {
     }
     module cmp                        { header "__utility/cmp.h" }
     module convert_to_integral        { header "__utility/convert_to_integral.h" }
+    module element_count              { header "__utility/element_count.h" }
     module exception_guard            { header "__utility/exception_guard.h" }
     module exchange                   { header "__utility/exchange.h" }
     module forward_like               { header "__utility/forward_like.h" }