Add abstractions that use memory accessible from both hosts and devices.

- `thrust::universal_vector`.
- `thrust::universal_ptr`.
- `thrust::universal_allocator`.

Change all backend fancy pointer and reference types to be aliases.

Substantially refactor `thrust::reference`.

Fix a bug that allowed `thrust::reference`s to const objects to be swapped:
https://godbolt.org/z/r9G4nY

Introduce a new `thrust::tagged_reference` type that breaks the circular
template argument dependency between `thrust::pointer` and `thrust::reference`.

Author: brycelelbach

CHANGELOG.md

@@ -12,8 +12,8 @@ The new `thrust::shuffle` algorithm has been tweaked to improve the randomness
 of the output.
 
 Our CMake package and build system continue to see improvements with
-improved `add_subdirectory` support, installation rules, status messages, and
-other features that make CUB easier to use from CMake projects.
+better `add_subdirectory` support, installation rules, status messages, and
+other features that make Thrust easier to use from CMake projects.
 
 The release includes several other bugfixes and modernizations, and received
 updates from 12 contributors.
@@ -72,11 +72,12 @@ updates from 12 contributors.
   - Github's `thrust/cub` repository is now `NVIDIA/cub`
   - Development has moved from the `master` branch to the `main` branch.
 
-# Thrust 1.10.0 (NVIDIA HPC SDK 20.9)
+# Thrust 1.10.0 (NVIDIA HPC SDK 20.9, CUDA Toolkit 11.2)
 
 ## Summary
 
-Thrust 1.10.0 is the major release accompanying the NVIDIA HPC SDK 20.9 release.
+Thrust 1.10.0 is the major release accompanying the NVIDIA HPC SDK 20.9 release
+  and the CUDA Toolkit 11.2 release.
 It drops support for C++03, GCC < 5, Clang < 6, and MSVC < 2017.
 It also overhauls CMake support.
 Finally, we now have a Code of Conduct for contributors:

examples/sorting_aos_vs_soa.cu

@@ -1,3 +1,4 @@
+#include <thrust/host_vector.h>
 #include <thrust/device_vector.h>
 #include <thrust/sort.h>
 #include <thrust/random.h>
@@ -7,7 +8,7 @@
 
 // This examples compares sorting performance using Array of Structures (AoS)
 // and Structure of Arrays (SoA) data layout.  Legacy applications will often
-// store data in C/C++ structs, such as MyStruct defined below.  Although 
+// store data in C/C++ structs, such as MyStruct defined below.  Although
 // Thrust can process array of structs, it is typically less efficient than
 // the equivalent structure of arrays layout.  In this particular example,
 // the optimized SoA approach is approximately *five times faster* than the
@@ -57,7 +58,7 @@ int main(void)
 {
   size_t N = 2 * 1024 * 1024;
 
-  // Sort Key-Value pairs using Array of Structures (AoS) storage 
+  // Sort Key-Value pairs using Array of Structures (AoS) storage
   {
     thrust::device_vector<MyStruct> structures(N);
 
@@ -71,7 +72,7 @@ int main(void)
     std::cout << "AoS sort took " << 1e3 * t.elapsed() << " milliseconds" << std::endl;
   }
 
-  // Sort Key-Value pairs using Structure of Arrays (SoA) storage 
+  // Sort Key-Value pairs using Structure of Arrays (SoA) storage
   {
     thrust::device_vector<int>   keys(N);
     thrust::device_vector<float> values(N);

examples/transform_input_output_iterator.cu

@@ -1,3 +1,4 @@
+#include <thrust/host_vector.h>
 #include <thrust/device_vector.h>
 #include <thrust/functional.h>
 #include <thrust/gather.h>

testing/cuda/managed_memory_pointer.cu

@@ -24,6 +24,13 @@ template<typename T, typename U, typename Allocator>
     typename Allocator::template rebind<U>::other> type;
 };
 
+template<typename T, typename U, typename Allocator>
+  struct rebind_vector<thrust::universal_vector<T, Allocator>, U>
+{
+  typedef thrust::universal_vector<U,
+    typename Allocator::template rebind<U>::other> type;
+};
+
 #define BINARY_FUNCTIONAL_PLACEHOLDERS_TEST(name, op, reference_functor, type_list) \
 template<typename Vector> \
   struct TestFunctionalPlaceholders##name \

testing/functional_placeholders_bitwise.cu

@@ -23,6 +23,13 @@ template<typename T, typename U, typename Allocator>
     typename Allocator::template rebind<U>::other> type;
 };
 
+template<typename T, typename U, typename Allocator>
+  struct rebind_vector<thrust::universal_vector<T, Allocator>, U>
+{
+  typedef thrust::universal_vector<U,
+    typename Allocator::template rebind<U>::other> type;
+};
+
 #define BINARY_FUNCTIONAL_PLACEHOLDERS_TEST(name, reference_operator, functor) \
 template<typename Vector> \
   void TestFunctionalPlaceholders##name(void) \

testing/functional_placeholders_logical.cu

@@ -23,6 +23,13 @@ template<typename T, typename U, typename Allocator>
     typename Allocator::template rebind<U>::other> type;
 };
 
+template<typename T, typename U, typename Allocator>
+  struct rebind_vector<thrust::universal_vector<T, Allocator>, U>
+{
+  typedef thrust::universal_vector<U,
+    typename Allocator::template rebind<U>::other> type;
+};
+
 #define BINARY_FUNCTIONAL_PLACEHOLDERS_TEST(name, reference_operator, functor) \
 template<typename Vector> \
   void TestFunctionalPlaceholdersBinary##name(void) \