Architecture and OS identification macros

libcudacxx/include/cuda/__cccl_config

@@ -11,6 +11,7 @@
 #ifndef _CUDA__CCCL_CONFIG
 #define _CUDA__CCCL_CONFIG
 
+#include <cuda/std/__cccl/architecture.h> // IWYU pragma: export
 #include <cuda/std/__cccl/assert.h> // IWYU pragma: export
 #include <cuda/std/__cccl/attributes.h> // IWYU pragma: export
 #include <cuda/std/__cccl/builtin.h> // IWYU pragma: export
@@ -21,6 +22,7 @@
 #include <cuda/std/__cccl/exceptions.h> // IWYU pragma: export
 #include <cuda/std/__cccl/execution_space.h> // IWYU pragma: export
 #include <cuda/std/__cccl/extended_floating_point.h> // IWYU pragma: export
+#include <cuda/std/__cccl/os.h> // IWYU pragma: export
 #include <cuda/std/__cccl/preprocessor.h> // IWYU pragma: export
 #include <cuda/std/__cccl/ptx_isa.h> // IWYU pragma: export
 #include <cuda/std/__cccl/rtti.h> // IWYU pragma: export

libcudacxx/include/cuda/std/__cccl/architecture.h

@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of libcu++, the C++ Standard Library for your entire system,
+// 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
+// SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __CCCL_ARCH_H
+#define __CCCL_ARCH_H
+
+// The header provides the following macros to determine the host architecture:
+//
+// _CCCL_ARCH(ARM64)     ARM64
+// _CCCL_ARCH(X86)       X86 both 32 and 64 bit
+// _CCCL_ARCH(X86_64)    X86 64 bit
+// _CCCL_ARCH(X86_32)    X86 64 bit
+// _CCCL_ARCH(64BIT)     Any 64 bit OS (supported by CUDA)
+// _CCCL_ARCH(32BIT)     Any 32 bit OS (supported by CUDA)
+
+// Determine the host compiler and its version
+#if (defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC) /*emulation*/)
+#  define _CCCL_ARCH_ARM64_() 1
+#else
+#  define _CCCL_ARCH_ARM64_() 0
+#endif
+
+#if defined(_M_X64) || defined(__amd64__) || defined(__x86_64__)
+#  define _CCCL_ARCH_X86_64_() 1
+#else
+#  define _CCCL_ARCH_X86_64_() 0
+#endif
+
+#if defined(_M_IX86)
+#  define _CCCL_ARCH_X86_32_() 1
+#else
+#  define _CCCL_ARCH_X86_32_() 0
+#endif
+
+#if _CCCL_ARCH_X86_64_() || _CCCL_ARCH_X86_32_()
+#  define _CCCL_ARCH_X86_() 1
+#else
+#  define _CCCL_ARCH_X86_() 0
+#endif
+
+#if _CCCL_ARCH_X86_64_() || _CCCL_ARCH_ARM64_()
+#  define _CCCL_ARCH_64BIT_() 1
+#  define _CCCL_ARCH_32BIT_() 0
+#else
+#  define _CCCL_ARCH_64BIT_() 0
+#  define _CCCL_ARCH_32BIT_() 1
+#endif
+
+#define _CCCL_ARCH(...) _CCCL_ARCH_##__VA_ARGS__##_()
+
+#endif // __CCCL_ARCH_H

libcudacxx/include/cuda/std/__cccl/os.h

@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of libcu++, the C++ Standard Library for your entire system,
+// 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
+// SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __CCCL_OS_H
+#define __CCCL_OS_H
+
+// The header provides the following macros to determine the host architecture:
+//
+// _CCCL_OS(WINDOWS)
+// _CCCL_OS(LINUX)
+// _CCCL_OS(ANDROID)
+// _CCCL_OS(QNX)
+
+// Determine the host compiler and its version
+#if defined(_WIN32)
+#  define _CCCL_OS_WINDOWS_() 1
+#else
+#  define _CCCL_OS_WINDOWS_() 0
+#endif
+
+#if defined(__linux__)
+#  define _CCCL_OS_LINUX_() 1
+#else
+#  define _CCCL_OS_LINUX_() 0
+#endif
+
+#if defined(__ANDROID__)
+#  define _CCCL_OS_ANDROID_() 1
+#else
+#  define _CCCL_OS_ANDROID_() 0
+#endif
+
+#if defined(__QNX__) || defined(__QNXNTO__)
+#  define _CCCL_OS_QNX_() 1
+#else
+#  define _CCCL_OS_QNX_() 0
+#endif
+
+#define _CCCL_OS(...) _CCCL_OS_##__VA_ARGS__##_()
+
+#endif // __CCCL_OS_H

libcudacxx/test/libcudacxx/std/cccl/architecture.compile.pass.cpp

@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES.
+//
+//===----------------------------------------------------------------------===//
+
+#include <cuda/std/__cccl/architecture.h>
+#include <cuda/std/__cccl/compiler.h>
+
+#if _CCCL_COMPILER(MSVC)
+#  include <intrin.h>
+#elif _CCCL_COMPILER(GCC) || _CCCL_COMPILER(CLANG)
+#  include <cpuid.h>
+#endif
+
+#if _CCCL_ARCH(ARM64)
+#  include <arm_acle.h>
+#endif
+
+int main(int, char**)
+{
+#if _CCCL_ARCH(64BIT)
+  static_assert(sizeof(void*) == 8, "");
+#endif
+#if _CCCL_ARCH(32BIT)
+  static_assert(sizeof(void*) == 4, "");
+#endif
+#if _CCCL_ARCH(X86) && (_CCCL_COMPILER(MSVC) || _CCCL_COMPILER(GCC) || _CCCL_COMPILER(CLANG))
+  static_cast<void>(__cpuidex);
+#endif
+#if _CCCL_ARCH(ARM64)
+  static_cast<void>(__clz);
+#endif
+  return 0;
+}

libcudacxx/test/libcudacxx/std/cccl/os.compile.pass.cpp

@@ -0,0 +1,50 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES.
+//
+//===----------------------------------------------------------------------===//
+
+#include <cuda/std/__cccl/os.h>
+
+#if _CCCL_OS(WINDOWS)
+#  include <windows.h>
+constexpr int windows = 1;
+#else
+constexpr int windows = 0;
+#endif
+
+#if _CCCL_OS(LINUX)
+#  include <unistd.h>
+constexpr int linux_ = 1;
+#else
+constexpr int linux_ = 0;
+#endif
+
+#if _CCCL_OS(ANDROID)
+#  include <android/api-level.h>
+constexpr int android = 1;
+#endif
+
+#if _CCCL_OS(QNX)
+#  include <qnx.h>
+constexpr int qnx = 1;
+#endif
+
+int main(int, char**)
+{
+  static_assert(windows + linux_ == 1, "");
+#if _CCCL_OS(ANDROID) || _CCCL_OS(QNX)
+  static_assert(linux_ == 1, "");
+  static_assert(android + qnx == 1, "");
+#endif
+#if _CCCL_OS(LINUX)
+  static_assert(windows == 0, "");
+#endif
+#if _CCCL_OS(WINDOWS)
+  static_assert(android + qnx + linux_ == 0, "");
+#endif
+  return 0;
+}