[SYCL] Import/preprocess boost/mp11 at build time to use in SYCL headers.

sycl/CMakeLists.txt

@@ -142,6 +142,8 @@ configure_file("${version_header}.in" "${version_header}")
 set(feature_header "${sycl_inc_dir}/CL/sycl/feature_test.hpp")
 configure_file("${feature_header}.in" "${feature_header}")
 
+include(AddBoostMp11Headers)
+
 # This is workaround to detect changes (add or modify) in subtree which
 # are not detected by copy_directory command.
 # TODO: detect and process remove header/directory case
@@ -159,7 +161,8 @@ string(REPLACE "${sycl_inc_dir}" "${SYCL_INCLUDE_BUILD_DIR}"
 add_custom_target(sycl-headers
   DEPENDS ${OUT_HEADERS_IN_SYCL_DIR}
           ${OUT_HEADERS_IN_CL_DIR}
-          ${OUT_HEADERS_IN_STD_DIR})
+          ${OUT_HEADERS_IN_STD_DIR}
+          boost_mp11-headers)
 
 add_custom_command(
   OUTPUT  ${OUT_HEADERS_IN_SYCL_DIR}
@@ -177,6 +180,7 @@ add_custom_command(
 install(DIRECTORY "${sycl_inc_dir}/sycl" DESTINATION ${SYCL_INCLUDE_DIR} COMPONENT sycl-headers)
 install(DIRECTORY "${sycl_inc_dir}/CL" DESTINATION ${SYCL_INCLUDE_DIR}/sycl COMPONENT sycl-headers)
 install(DIRECTORY "${sycl_inc_dir}/std" DESTINATION ${SYCL_INCLUDE_DIR} COMPONENT sycl-headers)
+install(DIRECTORY ${BOOST_MP11_DESTINATION_DIR} DESTINATION ${SYCL_INCLUDE_DIR}/sycl COMPONENT boost_mp11-headers)
 
 set(SYCL_RT_LIBS sycl)
 if (MSVC)
@@ -315,6 +319,7 @@ endif()
 # Listed here are component names contributing the package
 set( SYCL_TOOLCHAIN_DEPLOY_COMPONENTS
      append-file
+     boost_mp11-headers
      clang
      clang-offload-wrapper
      clang-offload-bundler

sycl/cmake/modules/AddBoostMp11Headers.cmake

@@ -0,0 +1,55 @@
+# boost/mp11 headers import and preprocessing
+# See more comments in cmake/modules/PreprocessBoostMp11Headers.cmake
+
+include(FetchContent)
+
+set(BOOST_MP11_GIT_REPO https://github.com/boostorg/mp11.git)
+# Author: pdimov
+# Date: Feb 16, 2022
+# Comment:
+#   Merge pull request #71 from grisumbras/feature/mp_valid_and_true
+set(BOOST_MP11_GIT_TAG 7bc4e1ae9b36ec8ee635c3629b59ec525bbe82b9)
+
+# Either download from github or use existing if BOOST_MP11_SOURCE_DIR is set
+if (NOT DEFINED BOOST_MP11_SOURCE_DIR)
+  message(STATUS "BOOST_MP11_SOURCE_DIR not set, downloading boost/mp11 headers from ${BOOST_MP11_GIT_REPO}")
+
+  FetchContent_Declare(boost_mp11
+    GIT_REPOSITORY ${BOOST_MP11_GIT_REPO}
+    GIT_TAG ${BOOST_MP11_GIT_TAG}
+  )
+  FetchContent_GetProperties(boost_mp11)
+  FetchContent_MakeAvailable(boost_mp11)
+
+  set(BOOST_MP11_SOURCE_DIR ${boost_mp11_SOURCE_DIR})
+  set(BOOST_MP11_SRC_PATH ${BOOST_MP11_GIT_REPO})
+  set(BOOST_MP11_SRC_ID "git commit hash: ${BOOST_MP11_GIT_TAG}")
+else (NOT DEFINED BOOST_MP11_SOURCE_DIR)
+  message(STATUS "Using boost/mp11 headers from ${BOOST_MP11_SOURCE_DIR}")
+  set(BOOST_MP11_SRC_PATH ${BOOST_MP11_SOURCE_DIR})
+  set(BOOST_MP11_SRC_ID "ID not set")
+endif(NOT DEFINED BOOST_MP11_SOURCE_DIR)
+
+# Read all header file names into HEADERS_BOOST_MP11
+file(GLOB_RECURSE HEADERS_BOOST_MP11 CONFIGURE_DEPENDS "${BOOST_MP11_SOURCE_DIR}/include/boost/*")
+
+set(BOOST_MP11_DESTINATION_DIR ${SYCL_INCLUDE_BUILD_DIR}/sycl/detail/boost)
+string(REPLACE "${BOOST_MP11_SOURCE_DIR}/include/boost" "${BOOST_MP11_DESTINATION_DIR}"
+  OUT_HEADERS_BOOST_MP11 "${HEADERS_BOOST_MP11}")
+
+# The target which produces preprocessed boost/mp11 headers
+add_custom_target(boost_mp11-headers
+  DEPENDS ${OUT_HEADERS_BOOST_MP11})
+
+# Run preprocessing on each header, output result into
+# ${BOOST_MP11_DESTINATION_DIR}
+add_custom_command(
+  OUTPUT ${OUT_HEADERS_BOOST_MP11}
+  DEPENDS ${HEADERS_BOOST_MP11}
+  COMMAND ${CMAKE_COMMAND}
+    -DIN=${BOOST_MP11_SOURCE_DIR}/include/boost
+    -DOUT=${BOOST_MP11_DESTINATION_DIR}
+    -DSRC_PATH="${BOOST_MP11_SRC_PATH}"
+    -DSRC_ID="${BOOST_MP11_SRC_ID}"
+    -P ${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules/PreprocessBoostMp11Headers.cmake
+  COMMENT "Preprocessing boost/mp11 headers ${BOOST_MP11_SOURCE_DIR}/include/boost -> ${BOOST_MP11_DESTINATION_DIR}...")

sycl/cmake/modules/PreprocessBoostMp11Headers.cmake

@@ -0,0 +1,106 @@
+# Preprocess boost/mp11 headers to allow using specific version of mp11 (as
+# defined in these project's cmake files) within SYCL library w/o risk of
+# conflict with user program using another version of boost/mp11. Basically,
+# this transformation moves all APIs from boost namespace to sycl::boost and
+# adds SYCL_ prefix to boost macros names. See more specific comments in the
+# code below.
+# Variables which must be set by the caller to control behavior of this module:
+# - IN
+#   The source directory with mp11 headers, must contain mp11.h.
+# - OUT
+#   The destination directory where preprocessed source headers are put.
+# - SRC_PATH
+#   An URL or directory name the source directory originates from. Used only in
+#   generated README text.
+# - SRC_ID
+#   Git hash/tag or other ID identifying the original source. Used only in
+#   generated README text.
+#
+# Assumed to be invoked as a script:
+# ${CMAKE_COMMAND} -DIN=... -DOUT=... -DSRC_PATH=... -DSRC_ID=... -P <this file>
+
+function(preprocess_mp11_header)
+  cmake_parse_arguments(
+    MP11_HDR                   # prefix
+    ""                         # options
+    "SRC_NAME;DST_NAME;IN_DIR" # one value keywords
+    ""                         # multi-value keywords
+    ${ARGN})                   # arguments
+  file(READ ${MP11_HDR_SRC_NAME} FILE_CONTENTS)
+
+  # 1) replace `BOOST_*` macros with `SYCL_BOOST_*`.
+  string(REGEX REPLACE
+    "([ \t\n\r!])BOOST_"
+    "\\1SYCL_DETAIL_BOOST_"
+    FILE_CONTENTS "${FILE_CONTENTS}")
+  # 2) replace `namespace boost { ... }` with
+  # `namespace sycl { namespace detail { namespace boost { ... } } }`
+  string(REGEX REPLACE
+    "(\n[ \t]*namespace[ \t\n\r]+boost)"
+    "namespace sycl\n{\nnamespace detail\n{\\1"
+    FILE_CONTENTS "${FILE_CONTENTS}")
+  # ... use '} // namespace boost' as a marker for end-of-scope '}' replacement
+  string(REGEX REPLACE
+    "(\n[ \t]*}[ \t]*//[ \t]*namespace[ \t]+boost[ \t]*\n)"
+    "\\1} // namespace detail\n} // namespace sycl\n"
+    FILE_CONTENTS "${FILE_CONTENTS}")
+  # 3) replace `boost` in `#include <boost/...>` or `#include "boost/..."` with
+  # `sycl/detail/boost`
+  string(REGEX REPLACE
+    "(\n#include[ \t]*[<\"])boost"
+    "\\1sycl/detail/boost"
+    FILE_CONTENTS "${FILE_CONTENTS}")
+
+  set(SYCL_DERIVED_COPYRIGHT_NOTICE "\
+  // -*- C++ -*-\n\
+  //===----------------------------------------------------------------------===//\n\
+  // Modifications Copyright Intel Corporation 2022\n\
+  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception\n\
+  //===----------------------------------------------------------------------===//\n\
+  // Auto-generated from boost/mp11 sources https://github.com/boostorg/mp11\n\n")
+
+  # 4) add proper copyright notice atop
+  string(PREPEND FILE_CONTENTS ${SYCL_DERIVED_COPYRIGHT_NOTICE})
+  file(WRITE ${MP11_HDR_DST_NAME} "${FILE_CONTENTS}")
+endfunction(preprocess_mp11_header)
+
+function(preprocess_mp11_headers)
+  cmake_parse_arguments(
+    MP11_HDRS                # prefix
+    ""                       # options
+    "IN;OUT;SRC_PATH;SRC_ID" # one value keywords
+    ""                       # multi-value keywords
+    ${ARGN})                 # arguments
+
+  # 1) Perform necessary preprocessing of headers.
+  file(GLOB_RECURSE BOOST_MP11_SOURCES "${MP11_HDRS_IN}/*")
+
+  foreach(SRC ${BOOST_MP11_SOURCES})
+    string(REPLACE "${MP11_HDRS_IN}" "${MP11_HDRS_OUT}" DST "${SRC}")
+    preprocess_mp11_header(
+      SRC_NAME ${SRC}
+      DST_NAME ${DST}
+      IN_DIR ${MP11_HDRS_IN}
+    )
+  endforeach(SRC ${BOOST_MP11_SOURCES})
+
+  # 2) Add SYCL_README.txt to the output directory root
+  set(SYCL_README_TEXT "\
+  This directory contains boost/mp11 headers imported from\n\
+    ${MP11_HDRS_SRC_PATH} (${MP11_HDRS_SRC_ID})\n\
+  and adapted for use in SYCL headers in a way that does not conflict with\n\
+  potential use of boost in user code. Particularly, `BOOST_*` macros are\n\
+  replaced with `SYCL_DETAIL_BOOST_*`, APIs are moved into the top-level
+  `sycl::detail` namespace. For example, `sycl::detail::boost::mp11::mp_list`.\n")
+
+  set(SYCL_README_FILE_NAME "${MP11_HDRS_OUT}/README.txt")
+
+  file(WRITE ${SYCL_README_FILE_NAME} "${SYCL_README_TEXT}")
+endfunction(preprocess_mp11_headers)
+
+preprocess_mp11_headers(
+    IN ${IN}
+    OUT ${OUT}
+    SRC_PATH ${SRC_PATH}
+    SRC_ID ${SRC_ID}
+)

sycl/test/basic_tests/boost_mp11_import_sanity_check.cpp

@@ -0,0 +1,48 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+// Modifications Copyright Intel Corporation 2022
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//===----------------------------------------------------------------------===//
+// Based on boost/mp11 tests obtained from
+//  https://github.com/boostorg/mp11/blob/develop/test/mp_fill.cpp
+//  (git commit a231733).
+
+//===----------------------------------------------------------------------===//
+//  Copyright 2015 Peter Dimov.
+//
+// Distributed under the Boost Software License, Version 1.0.
+//
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+//===----------------------------------------------------------------------===//
+
+// RUN: %clangxx -fsycl -fsycl-targets=%sycl_triple -c %s
+
+// This is a sanity check test to verify that the automatic boost/mp11 import
+// into SYCL is not badly broken.
+
+#include <type_traits>
+
+#include <sycl/detail/boost/mp11.hpp>
+
+struct X1 {};
+
+int main() {
+  using sycl::detail::boost::mp11::mp_fill;
+  using sycl::detail::boost::mp11::mp_list;
+
+  using L1 = mp_list<int, void(), float[]>;
+  static_assert(std::is_same_v<mp_fill<L1, X1>, mp_list<X1, X1, X1>>);
+
+  //
+
+  using L2 = std::tuple<int, char, float>;
+  static_assert(std::is_same_v<mp_fill<L2, X1>, std::tuple<X1, X1, X1>>);
+
+  //
+
+  using L3 = std::pair<char, double>;
+  static_assert(std::is_same_v<mp_fill<L3, X1>, std::pair<X1, X1>>);
+
+  return 0;
+}