Revert "Revert "Utilize allocate_at_least (microsoft#3712)""

This reverts commit 8ad049e.

stl/inc/deque

@@ -1557,12 +1557,13 @@ private:
 
             _Newsize *= 2;
         }
-        _Count = _Newsize - _Mapsize();
 
         size_type _Myboff = _Myoff() / _Block_size;
-        _Mapptr _Newmap   = _Almap.allocate(_Mapsize() + _Count);
+        _Mapptr _Newmap   = _Allocate_at_least_helper(_Almap, _Newsize);
         _Mapptr _Myptr    = _Newmap + _Myboff;
 
+        _Count = _Newsize - _Mapsize();
+
         _Myptr = _STD uninitialized_copy(_Map() + _Myboff, _Map() + _Mapsize(), _Myptr); // copy initial to end
         if (_Myboff <= _Count) { // increment greater than offset of initial block
             _Myptr = _STD uninitialized_copy(_Map(), _Map() + _Myboff, _Myptr); // copy rest of old

stl/inc/sstream

@@ -261,7 +261,7 @@ protected:
             return _Traits::eof();
         }
 
-        const auto _Newptr = _Unfancy(_Al.allocate(_Newsize));
+        const auto _Newptr = _Unfancy(_Allocate_at_least_helper(_Al, _Newsize));
         _Traits::copy(_Newptr, _Oldptr, _Oldsize);
 
         const auto _New_pnext = _Newptr + _Oldsize;
@@ -430,7 +430,7 @@ protected:
         return pos_type{_Off};
     }
 
-    void _Init(const _Elem* _Ptr, _Mysize_type _Count, int _State) {
+    void _Init(const _Elem* _Ptr, const _Mysize_type _Count, int _State) {
         // initialize buffer to [_Ptr, _Ptr + _Count), set state
         _State &= ~_From_rvalue;
 
@@ -440,9 +440,10 @@ protected:
 
         if (_Count != 0 && (_State & (_Noread | _Constant)) != (_Noread | _Constant)) {
             // finite buffer that can be read or written, set it up
-            const auto _Pnew = _Unfancy(_Al.allocate(_Count));
+            _Mysize_type _Newsize = _Count;
+            const auto _Pnew      = _Unfancy(_Allocate_at_least_helper(_Al, _Newsize));
             _Traits::copy(_Pnew, _Ptr, _Count);
-            _Seekhigh = _Pnew + _Count;
+            _Seekhigh = _Pnew + _Newsize;
 
             if (!(_State & _Noread)) {
                 _Mysb::setg(_Pnew, _Pnew, _Seekhigh); // setup read buffer

stl/inc/syncstream

@@ -120,10 +120,10 @@ public:
             if (_Al != _Right_al) {
                 _Tidy();
 
-                const _Size_type _Right_buf_size  = _Right._Get_buffer_size();
+                _Size_type _Right_buf_size        = _Right._Get_buffer_size();
                 const _Size_type _Right_data_size = _Right._Get_data_size();
 
-                _Elem* const _New_ptr = _Unfancy(_Al.allocate(_Right_buf_size));
+                _Elem* const _New_ptr = _Unfancy(_Allocate_at_least_helper(_Al, _Right_buf_size));
                 _Traits::copy(_New_ptr, _Right.pbase(), _Right_data_size);
 
                 streambuf_type::setp(_New_ptr, _New_ptr + _Right_data_size, _New_ptr + _Right_buf_size);
@@ -217,11 +217,11 @@ protected:
             return _Traits::eof();
         }
 
-        const _Size_type _New_capacity  = _Calculate_growth(_Buf_size, _Buf_size + 1, _Max_allocation);
+        _Size_type _New_capacity        = _Calculate_growth(_Buf_size, _Buf_size + 1, _Max_allocation);
         _Elem* const _Old_ptr           = streambuf_type::pbase();
         const _Size_type _Old_data_size = _Get_data_size();
 
-        _Elem* const _New_ptr = _Unfancy(_Al.allocate(_New_capacity));
+        _Elem* const _New_ptr = _Unfancy(_Allocate_at_least_helper(_Al, _New_capacity));
         _Traits::copy(_New_ptr, _Old_ptr, _Old_data_size);
         if (0 < _Buf_size) {
             _Al.deallocate(_Refancy<_Pointer>(_Old_ptr), _Buf_size);
@@ -237,8 +237,9 @@ private:
     static constexpr _Size_type _Min_size = 32; // constant for minimum buffer size
 
     void _Init() {
-        _Elem* const _New_ptr = _Unfancy(_Getal().allocate(_Min_size));
-        streambuf_type::setp(_New_ptr, _New_ptr + _Min_size);
+        _Size_type _New_capacity = _Min_size;
+        _Elem* const _New_ptr    = _Unfancy(_Allocate_at_least_helper(_Getal(), _New_capacity));
+        streambuf_type::setp(_New_ptr, _New_ptr + _New_capacity);
     }
 
     void _Tidy() noexcept {

stl/inc/vector

@@ -825,10 +825,10 @@ private:
             _Xlength();
         }
 
-        const size_type _Newsize     = _Oldsize + 1;
-        const size_type _Newcapacity = _Calculate_growth(_Newsize);
+        const size_type _Newsize = _Oldsize + 1;
+        size_type _Newcapacity   = _Calculate_growth(_Newsize);
 
-        const pointer _Newvec           = _Al.allocate(_Newcapacity);
+        const pointer _Newvec           = _Allocate_at_least_helper(_Al, _Newcapacity);
         const pointer _Constructed_last = _Newvec + _Whereoff + 1;
         pointer _Constructed_first      = _Constructed_last;
 
@@ -912,10 +912,10 @@ private:
                 _Xlength();
             }
 
-            const size_type _Newsize     = _Oldsize + _Count;
-            const size_type _Newcapacity = _Calculate_growth(_Newsize);
+            const size_type _Newsize = _Oldsize + _Count;
+            size_type _Newcapacity   = _Calculate_growth(_Newsize);
 
-            const pointer _Newvec           = _Al.allocate(_Newcapacity);
+            const pointer _Newvec           = _Allocate_at_least_helper(_Al, _Newcapacity);
             const pointer _Constructed_last = _Newvec + _Oldsize + _Count;
             pointer _Constructed_first      = _Constructed_last;
 
@@ -1033,10 +1033,10 @@ public:
                 _Xlength();
             }
 
-            const size_type _Newsize     = _Oldsize + _Count;
-            const size_type _Newcapacity = _Calculate_growth(_Newsize);
+            const size_type _Newsize = _Oldsize + _Count;
+            size_type _Newcapacity   = _Calculate_growth(_Newsize);
 
-            const pointer _Newvec           = _Al.allocate(_Newcapacity);
+            const pointer _Newvec           = _Allocate_at_least_helper(_Al, _Newcapacity);
             const pointer _Constructed_last = _Newvec + _Whereoff + _Count;
             pointer _Constructed_first      = _Constructed_last;
 
@@ -1128,10 +1128,10 @@ private:
                 _Xlength();
             }
 
-            const size_type _Newsize     = _Oldsize + _Count;
-            const size_type _Newcapacity = _Calculate_growth(_Newsize);
+            const size_type _Newsize = _Oldsize + _Count;
+            size_type _Newcapacity   = _Calculate_growth(_Newsize);
 
-            const pointer _Newvec           = _Al.allocate(_Newcapacity);
+            const pointer _Newvec           = _Allocate_at_least_helper(_Al, _Newcapacity);
             const auto _Whereoff            = static_cast<size_type>(_Whereptr - _Oldfirst);
             const pointer _Constructed_last = _Newvec + _Whereoff + _Count;
             pointer _Constructed_first      = _Constructed_last;
@@ -1518,10 +1518,10 @@ private:
         pointer& _Myfirst = _My_data._Myfirst;
         pointer& _Mylast  = _My_data._Mylast;
 
-        const auto _Oldsize          = static_cast<size_type>(_Mylast - _Myfirst);
-        const size_type _Newcapacity = _Calculate_growth(_Newsize);
+        const auto _Oldsize    = static_cast<size_type>(_Mylast - _Myfirst);
+        size_type _Newcapacity = _Calculate_growth(_Newsize);
 
-        const pointer _Newvec         = _Al.allocate(_Newcapacity);
+        const pointer _Newvec         = _Allocate_at_least_helper(_Al, _Newcapacity);
         const pointer _Appended_first = _Newvec + _Oldsize;
         pointer _Appended_last        = _Appended_first;
 
@@ -1598,7 +1598,10 @@ public:
     }
 
 private:
-    _CONSTEXPR20 void _Reallocate_exactly(const size_type _Newcapacity) {
+    enum class _Reallocation_policy { _At_least, _Exactly };
+
+    template <_Reallocation_policy _Policy>
+    _CONSTEXPR20 void _Reallocate(size_type& _Newcapacity) {
         // set capacity to _Newcapacity (without geometric growth), provide strong guarantee
         auto& _Al         = _Getal();
         auto& _My_data    = _Mypair._Myval2;
@@ -1607,7 +1610,13 @@ private:
 
         const auto _Size = static_cast<size_type>(_Mylast - _Myfirst);
 
-        const pointer _Newvec = _Al.allocate(_Newcapacity);
+        pointer _Newvec;
+        if constexpr (_Policy == _Reallocation_policy::_At_least) {
+            _Newvec = _Allocate_at_least_helper(_Al, _Newcapacity);
+        } else {
+            _STL_INTERNAL_STATIC_ASSERT(_Policy == _Reallocation_policy::_Exactly);
+            _Newvec = _Al.allocate(_Newcapacity);
+        }
 
         _TRY_BEGIN
         if constexpr (is_nothrow_move_constructible_v<_Ty> || !is_copy_constructible_v<_Ty>) {
@@ -1675,14 +1684,14 @@ private:
     }
 
 public:
-    _CONSTEXPR20 void reserve(_CRT_GUARDOVERFLOW const size_type _Newcapacity) {
+    _CONSTEXPR20 void reserve(_CRT_GUARDOVERFLOW size_type _Newcapacity) {
         // increase capacity to _Newcapacity (without geometric growth), provide strong guarantee
         if (_Newcapacity > capacity()) { // something to do (reserve() never shrinks)
             if (_Newcapacity > max_size()) {
                 _Xlength();
             }
 
-            _Reallocate_exactly(_Newcapacity);
+            _Reallocate<_Reallocation_policy::_At_least>(_Newcapacity);
         }
     }
 
@@ -1694,7 +1703,8 @@ public:
             if (_Oldfirst == _Oldlast) {
                 _Tidy();
             } else {
-                _Reallocate_exactly(static_cast<size_type>(_Oldlast - _Oldfirst));
+                size_type _Newcapacity = static_cast<size_type>(_Oldlast - _Oldfirst);
+                _Reallocate<_Reallocation_policy::_Exactly>(_Newcapacity);
             }
         }
     }
@@ -1976,7 +1986,7 @@ private:
         return _Geometric; // geometric growth is sufficient
     }
 
-    _CONSTEXPR20 void _Buy_raw(const size_type _Newcapacity) {
+    _CONSTEXPR20 void _Buy_raw(size_type _Newcapacity) {
         // allocate array with _Newcapacity elements
         auto& _My_data    = _Mypair._Myval2;
         pointer& _Myfirst = _My_data._Myfirst;
@@ -1986,10 +1996,10 @@ private:
         _STL_INTERNAL_CHECK(!_Myfirst && !_Mylast && !_Myend); // check that *this is tidy
         _STL_INTERNAL_CHECK(0 < _Newcapacity && _Newcapacity <= max_size());
 
-        const auto _Newvec = _Getal().allocate(_Newcapacity);
-        _Myfirst           = _Newvec;
-        _Mylast            = _Newvec;
-        _Myend             = _Newvec + _Newcapacity;
+        const pointer _Newvec = _Allocate_at_least_helper(_Getal(), _Newcapacity);
+        _Myfirst              = _Newvec;
+        _Mylast               = _Newvec;
+        _Myend                = _Newvec + _Newcapacity;
     }
 
     _CONSTEXPR20 void _Buy_nonzero(const size_type _Newcapacity) {

stl/inc/xmemory

@@ -2174,6 +2174,18 @@ _NODISCARD constexpr bool _Allocators_equal(const _Alloc& _Lhs, const _Alloc& _R
     }
 }
 
+template <class _Alloc>
+_NODISCARD_RAW_PTR_ALLOC _CONSTEXPR20 typename allocator_traits<_Alloc>::pointer _Allocate_at_least_helper(
+    _Alloc& _Al, _CRT_GUARDOVERFLOW typename allocator_traits<_Alloc>::size_type& _Count) {
+#if _HAS_CXX23
+    auto [_Ptr, _Allocated] = allocator_traits<_Alloc>::allocate_at_least(_Al, _Count);
+    _Count                  = _Allocated;
+    return _Ptr;
+#else // _HAS_CXX23
+    return _Al.allocate(_Count);
+#endif // _HAS_CXX23
+}
+
 _EXPORT_STD template <class _FwdIt, class _Ty>
 _NODISCARD_REMOVE_ALG _CONSTEXPR20 _FwdIt remove(_FwdIt _First, const _FwdIt _Last, const _Ty& _Val) {
     // remove each matching _Val

stl/inc/xstring

@@ -2647,9 +2647,11 @@ private:
             return;
         }
 
-        _My_data._Myres               = _BUF_SIZE - 1;
-        const size_type _New_capacity = _Calculate_growth(_Count);
-        const pointer _New_ptr        = _Al.allocate(_New_capacity + 1); // throws
+        _My_data._Myres         = _BUF_SIZE - 1;
+        size_type _New_capacity = _Calculate_growth(_Count);
+        ++_New_capacity;
+        const pointer _New_ptr = _Allocate_at_least_helper(_Al, _New_capacity); // throws
+        --_New_capacity;
         _Construct_in_place(_My_data._Bx._Ptr, _New_ptr);
 
         _Start_element_lifetimes(_Unfancy(_New_ptr), _New_capacity + 1);
@@ -2691,8 +2693,10 @@ private:
             }
 
             if (_Count >= _BUF_SIZE) {
-                const size_type _New_capacity = _Calculate_growth(_Count);
-                const pointer _New_ptr        = _Al.allocate(_New_capacity + 1); // throws
+                size_type _New_capacity = _Calculate_growth(_Count);
+                ++_New_capacity;
+                const pointer _New_ptr = _Allocate_at_least_helper(_Al, _New_capacity); // throws
+                --_New_capacity;
                 _Construct_in_place(_My_data._Bx._Ptr, _New_ptr);
                 _My_data._Myres = _New_capacity;
 
@@ -2708,9 +2712,11 @@ private:
                         _Xlen_string(); // result too long
                     }
 
-                    const auto _Old_ptr           = _My_data._Myptr();
-                    const size_type _New_capacity = _Calculate_growth(_My_data._Mysize);
-                    const pointer _New_ptr        = _Al.allocate(_New_capacity + 1); // throws
+                    const auto _Old_ptr     = _My_data._Myptr();
+                    size_type _New_capacity = _Calculate_growth(_My_data._Mysize);
+                    ++_New_capacity;
+                    const pointer _New_ptr = _Allocate_at_least_helper(_Al, _New_capacity); // throws
+                    --_New_capacity;
 
                     _Start_element_lifetimes(_Unfancy(_New_ptr), _New_capacity + 1);
                     _Traits::copy(_Unfancy(_New_ptr), _Old_ptr, _My_data._Mysize);
@@ -2792,9 +2798,11 @@ public:
         _Container_proxy_ptr<_Alty> _Proxy(_Alproxy, _My_data); // throws
 
         if (_New_capacity < _New_size) {
-            _New_capacity           = _Calculate_growth(_New_size, _BUF_SIZE - 1, max_size());
-            const pointer _Fancyptr = _Getal().allocate(_New_capacity + 1); // throws
-            _Ptr                    = _Unfancy(_Fancyptr);
+            _New_capacity = _Calculate_growth(_New_size, _BUF_SIZE - 1, max_size());
+            ++_New_capacity;
+            const pointer _Fancyptr = _Allocate_at_least_helper(_Getal(), _New_capacity); // throws
+            --_New_capacity;
+            _Ptr = _Unfancy(_Fancyptr);
             _Construct_in_place(_My_data._Bx._Ptr, _Fancyptr);
 
             _Start_element_lifetimes(_Ptr, _New_capacity + 1);
@@ -2863,10 +2871,12 @@ public:
             _Xlen_string();
         }
 
-        const auto _New_capacity = _Calculate_growth(_New_size, _BUF_SIZE - 1, _Max);
-        auto&& _Alproxy          = _GET_PROXY_ALLOCATOR(_Alty, _Getal());
+        auto _New_capacity = _Calculate_growth(_New_size, _BUF_SIZE - 1, _Max);
+        auto&& _Alproxy    = _GET_PROXY_ALLOCATOR(_Alty, _Getal());
         _Container_proxy_ptr<_Alty> _Proxy(_Alproxy, _My_data); // throws
-        const pointer _Fancyptr = _Getal().allocate(_New_capacity + 1); // throws
+        ++_New_capacity;
+        const pointer _Fancyptr = _Allocate_at_least_helper(_Getal(), _New_capacity); // throws
+        --_New_capacity;
         // nothrow hereafter
         _Start_element_lifetimes(_Unfancy(_Fancyptr), _New_capacity + 1);
         _Construct_in_place(_My_data._Bx._Ptr, _Fancyptr);
@@ -2946,9 +2956,10 @@ public:
             _Result._Res = _My_data._Myres + 1;
         } else {
             // use _BUF_SIZE + 1 to avoid SSO, if the buffer is assigned back
-            _Result._Ptr = _Al.allocate(_BUF_SIZE + 1);
+            size_type _Allocated = _BUF_SIZE + 1;
+            _Result._Ptr         = _Allocate_at_least_helper(_Al, _Allocated);
             _Traits::copy(_Unfancy(_Result._Ptr), _My_data._Bx._Buf, _BUF_SIZE);
-            _Result._Res = _BUF_SIZE + 1;
+            _Result._Res = _Allocated;
         }
         _My_data._Orphan_all();
         _Tidy_init();
@@ -3167,9 +3178,11 @@ public:
 
                 if (_Right._Mypair._Myval2._Large_string_engaged()) {
                     const auto _New_size     = _Right._Mypair._Myval2._Mysize;
-                    const auto _New_capacity = _Calculate_growth(_New_size, 0, _Right.max_size());
+                    auto _New_capacity       = _Calculate_growth(_New_size, 0, _Right.max_size());
                     auto _Right_al_non_const = _Right_al;
-                    const auto _New_ptr      = _Right_al_non_const.allocate(_New_capacity + 1); // throws
+                    ++_New_capacity;
+                    const auto _New_ptr = _Allocate_at_least_helper(_Right_al_non_const, _New_capacity); // throws
+                    --_New_capacity;
 
                     _Start_element_lifetimes(_Unfancy(_New_ptr), _New_capacity + 1);
 
@@ -4736,9 +4749,11 @@ private:
         }
 
         const size_type _Old_capacity = _Mypair._Myval2._Myres;
-        const size_type _New_capacity = _Calculate_growth(_New_size);
+        size_type _New_capacity       = _Calculate_growth(_New_size);
         auto& _Al                     = _Getal();
-        const pointer _New_ptr        = _Al.allocate(_New_capacity + 1); // throws
+        ++_New_capacity;
+        const pointer _New_ptr = _Allocate_at_least_helper(_Al, _New_capacity); // throws
+        --_New_capacity;
 
         _Start_element_lifetimes(_Unfancy(_New_ptr), _New_capacity + 1);
         _Mypair._Myval2._Orphan_all();
@@ -4769,9 +4784,11 @@ private:
 
         const size_type _New_size     = _Old_size + _Size_increase;
         const size_type _Old_capacity = _My_data._Myres;
-        const size_type _New_capacity = _Calculate_growth(_New_size);
+        size_type _New_capacity       = _Calculate_growth(_New_size);
         auto& _Al                     = _Getal();
-        const pointer _New_ptr        = _Al.allocate(_New_capacity + 1); // throws
+        ++_New_capacity;
+        const pointer _New_ptr = _Allocate_at_least_helper(_Al, _New_capacity); // throws
+        --_New_capacity;
 
         _Start_element_lifetimes(_Unfancy(_New_ptr), _New_capacity + 1);
         _My_data._Orphan_all();

tests/std/test.lst

@@ -223,6 +223,7 @@ tests\GH_003022_substr_allocator
 tests\GH_003105_piecewise_densities
 tests\GH_003119_error_category_ctor
 tests\GH_003246_cmath_narrowing
+tests\GH_003570_allocate_at_least
 tests\GH_003617_vectorized_meow_element
 tests\GH_003676_format_large_hh_mm_ss_values
 tests\GH_003735_char_traits_signatures

tests/std/tests/GH_003570_allocate_at_least/env.lst

@@ -0,0 +1,4 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+RUNALL_INCLUDE ..\usual_latest_matrix.lst