Index: CMakeLists.txt =================================================================== --- CMakeLists.txt +++ CMakeLists.txt @@ -258,13 +258,6 @@ # Feature flags =============================================================== define_if(MSVC -D_CRT_SECURE_NO_WARNINGS) -define_if_not(LIBCXX_ENABLE_GLOBAL_FILESYSTEM_NAMESPACE -D_LIBCPP_HAS_NO_GLOBAL_FILESYSTEM_NAMESPACE) -define_if_not(LIBCXX_ENABLE_STDIN -D_LIBCPP_HAS_NO_STDIN) -define_if_not(LIBCXX_ENABLE_STDOUT -D_LIBCPP_HAS_NO_STDOUT) -define_if_not(LIBCXX_ENABLE_THREADS -D_LIBCPP_HAS_NO_THREADS) -define_if_not(LIBCXX_ENABLE_MONOTONIC_CLOCK -D_LIBCPP_HAS_NO_MONOTONIC_CLOCK) -define_if_not(LIBCXX_ENABLE_THREAD_UNSAFE_C_FUNCTIONS -D_LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS) - # Sanitizer flags ============================================================= @@ -301,6 +294,22 @@ message(WARNING "LLVM_USE_SANITIZER is not supported on this platform.") endif() endif() + +# Configuration file flags ===================================================== +config_define_if_not(LIBCXX_ENABLE_GLOBAL_FILESYSTEM_NAMESPACE _LIBCPP_HAS_NO_GLOBAL_FILESYSTEM_NAMESPACE) +config_define_if_not(LIBCXX_ENABLE_STDIN _LIBCPP_HAS_NO_STDIN) +config_define_if_not(LIBCXX_ENABLE_STDOUT _LIBCPP_HAS_NO_STDOUT) +config_define_if_not(LIBCXX_ENABLE_THREADS _LIBCPP_HAS_NO_THREADS) +config_define_if_not(LIBCXX_ENABLE_MONOTONIC_CLOCK _LIBCPP_HAS_NO_MONOTONIC_CLOCK) +config_define_if_not(LIBCXX_ENABLE_THREAD_UNSAFE_C_FUNCTIONS _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS) + +if (LIBCXX_NEEDS_SITE_CONFIG) + configure_file( + include/__config_site.in + ${LIBCXX_BINARY_DIR}/__config_site + @ONLY) +endif() + #=============================================================================== # Setup Source Code And Tests #=============================================================================== Index: cmake/Modules/HandleLibcxxFlags.cmake =================================================================== --- cmake/Modules/HandleLibcxxFlags.cmake +++ cmake/Modules/HandleLibcxxFlags.cmake @@ -49,6 +49,22 @@ endif() endmacro() +macro(config_define_if condition def) + if (${condition}) + set(${def} ON) + add_definitions(-D${def}) + set(LIBCXX_NEEDS_SITE_CONFIG ON) + endif() +endmacro() + +macro(config_define_if_not condition def) + if (NOT ${condition}) + set(${def} ON) + add_definitions(-D${def}) + set(LIBCXX_NEEDS_SITE_CONFIG ON) + endif() +endmacro() + # Add a specified list of flags to both 'LIBCXX_COMPILE_FLAGS' and # 'LIBCXX_LINK_FLAGS'. macro(add_flags) Index: docs/DesignDocs/CapturingConfigInfo.rst =================================================================== --- /dev/null +++ docs/DesignDocs/CapturingConfigInfo.rst @@ -0,0 +1,88 @@ +======================================================= +Capturing configuration information during installation +======================================================= + +.. contents:: + :local: + +The Problem +=========== + +Currently the libc++ supports building the library with a number of different +configuration options. Unfortunately all of that configuration information is +lost when libc++ is installed. In order to support "persistent" +configurations libc++ needs a mechanism to capture the configuration options +in the INSTALLED headers. + + +Design Goals +============ + +* The solution should not INSTALL any additional headers. We don't want an extra + #include slowing everybody down. + +* The solution should not unduly affect libc++ developers. The problem is limited + to installed versions of libc++ and the solution should be as well. + +* The solution should not modify any existing headers EXCEPT during installation. + It makes developers lives harder if they have to regenerate the libc++ headers + every time they are modified. + +* The solution should not make any of the libc++ headers dependant on + files generated by the build system. The headers should be able to compile + out of the box without any modification. + +* The solution should not have ANY effect on users who don't need special + configuration options. The vast majority of users will never need this so it + shouldn't cost them. + + +The Solution +============ + +When you first configure libc++ using CMake we check to see if we need to +capture any options. If we haven't been given any "persistent" options then +we do NOTHING. + +Otherwise we create a custom installation rule that modifies the installed __config +header. The rule first generates a dummy "__config_site" header containing the required +#defines. The contents of the dummy header are then prependend to the installed +__config header. By manually prepending the files we avoid the cost of an +extra #include and we allow the __config header to be ignorant of the extra + configuration all together. An example "__config" header generated when +-DLIBCXX_ENABLE_THREADS=OFF is given to CMake would look something like: + +.. code-block:: cpp + + //===----------------------------------------------------------------------===// + // + // The LLVM Compiler Infrastructure + // + // This file is dual licensed under the MIT and the University of Illinois Open + // Source Licenses. See LICENSE.TXT for details. + // + //===----------------------------------------------------------------------===// + + #ifndef _LIBCPP_CONFIG_SITE + #define _LIBCPP_CONFIG_SITE + + /* #undef _LIBCPP_HAS_NO_GLOBAL_FILESYSTEM_NAMESPACE */ + /* #undef _LIBCPP_HAS_NO_STDIN */ + /* #undef _LIBCPP_HAS_NO_STDOUT */ + #define _LIBCPP_HAS_NO_THREADS + /* #undef _LIBCPP_HAS_NO_MONOTONIC_CLOCK */ + /* #undef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS */ + + #endif + // -*- C++ -*- + //===--------------------------- __config ---------------------------------===// + // + // The LLVM Compiler Infrastructure + // + // This file is dual licensed under the MIT and the University of Illinois Open + // Source Licenses. See LICENSE.TXT for details. + // + //===----------------------------------------------------------------------===// + + #ifndef _LIBCPP_CONFIG + #define _LIBCPP_CONFIG Index: docs/index.rst =================================================================== --- docs/index.rst +++ docs/index.rst @@ -124,6 +124,12 @@ Design Documents ---------------- +.. toctree:: + :maxdepth: 1 + + DesignDocs/CapturingConfigInfo + + * ` design `_ * ` design `_ * `Status of debug mode `_ Index: include/CMakeLists.txt =================================================================== --- include/CMakeLists.txt +++ include/CMakeLists.txt @@ -1,10 +1,12 @@ if (NOT LIBCXX_INSTALL_SUPPORT_HEADERS) set(LIBCXX_SUPPORT_HEADER_PATTERN PATTERN "support" EXCLUDE) endif() + set(LIBCXX_HEADER_PATTERN PATTERN "*" PATTERN "CMakeLists.txt" EXCLUDE PATTERN ".svn" EXCLUDE + PATTERN "__config_site.in" EXCLUDE ${LIBCXX_SUPPORT_HEADER_PATTERN} ) @@ -22,4 +24,29 @@ ${LIBCXX_HEADER_PATTERN} PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ ) + + if (LIBCXX_NEEDS_SITE_CONFIG) + set(UNIX_CAT cat) + if (WIN32) + set(UNIX_CAT type) + endif() + # Generate and install a custom __config header. The new header is created + # by prepending __config_site to the current __config header. + add_custom_command(OUTPUT ${LIBCXX_BINARY_DIR}/__generated_config + COMMAND ${CMAKE_COMMAND} -E copy ${LIBCXX_BINARY_DIR}/__config_site ${LIBCXX_BINARY_DIR}/__generated_config + COMMAND ${UNIX_CAT} ${LIBCXX_SOURCE_DIR}/include/__config >> ${LIBCXX_BINARY_DIR}/__generated_config + DEPENDS ${LIBCXX_SOURCE_DIR}/include/__config + ${LIBCXX_BINARY_DIR}/__config_site + ) + # Add a target that executes the generation commands. + add_custom_target(generate_config_header ALL + DEPENDS ${LIBCXX_BINARY_DIR}/__generated_config) + # Install the generated header as __config. + install(FILES ${LIBCXX_BINARY_DIR}/__generated_config + DESTINATION include/c++/v1 + PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ + RENAME __config + COMPONENT libcxx) + endif() + endif() Index: include/__config_site.in =================================================================== --- /dev/null +++ include/__config_site.in @@ -0,0 +1,20 @@ +//===----------------------------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is dual licensed under the MIT and the University of Illinois Open +// Source Licenses. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#ifndef _LIBCPP_CONFIG_SITE +#define _LIBCPP_CONFIG_SITE + +#cmakedefine _LIBCPP_HAS_NO_GLOBAL_FILESYSTEM_NAMESPACE +#cmakedefine _LIBCPP_HAS_NO_STDIN +#cmakedefine _LIBCPP_HAS_NO_STDOUT +#cmakedefine _LIBCPP_HAS_NO_THREADS +#cmakedefine _LIBCPP_HAS_NO_MONOTONIC_CLOCK +#cmakedefine _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS + +#endif