Enable building monolithic shared library on macOS and Linux.

PiperOrigin-RevId: 638284938
Change-Id: I4189215d85862a8eeaff5c477ff2e47252fa52d3

CMake/AbseilDll.cmake

@@ -747,7 +747,12 @@ function(absl_make_dll)
   else()
     set(_dll "abseil_dll")
     set(_dll_files ${ABSL_INTERNAL_DLL_FILES})
-    set(_dll_libs "")
+    set(_dll_libs
+      Threads::Threads
+      # TODO(#1495): Use $<LINK_LIBRARY:FRAMEWORK,CoreFoundation> once our
+      # minimum CMake version >= 3.24
+      $<$<PLATFORM_ID:Darwin>:-Wl,-framework,CoreFoundation>
+    )
     set(_dll_compile_definitions "")
     set(_dll_includes "")
     set(_dll_consume "ABSL_CONSUME_DLL")

CMakeLists.txt

@@ -149,6 +149,14 @@ set(ABSL_LOCAL_GOOGLETEST_DIR "/usr/src/googletest" CACHE PATH
   "If ABSL_USE_GOOGLETEST_HEAD is OFF and ABSL_GOOGLETEST_URL is not set, specifies the directory of a local GoogleTest checkout."
   )
 
+option(ABSL_BUILD_MONOLITHIC_SHARED_LIBS
+  "Build Abseil as a single shared library (always enabled for Windows)"
+  OFF
+)
+if(NOT BUILD_SHARED_LIBS AND ABSL_BUILD_MONOLITHIC_SHARED_LIBS)
+  message(WARNING "Not building a shared library because BUILD_SHARED_LIBS is not set. Ignoring ABSL_BUILD_MONOLITHIC_SHARED_LIBS.")
+endif()
+
 if((BUILD_TESTING AND ABSL_BUILD_TESTING) OR ABSL_BUILD_TEST_HELPERS)
   if (ABSL_USE_EXTERNAL_GOOGLETEST)
     if (ABSL_FIND_GOOGLETEST)

absl/copts/AbseilConfigureCopts.cmake

@@ -3,7 +3,7 @@ include(GENERATED_AbseilCopts)
 
 set(ABSL_DEFAULT_LINKOPTS "")
 
-if (BUILD_SHARED_LIBS AND MSVC)
+if (BUILD_SHARED_LIBS AND (MSVC OR ABSL_BUILD_MONOLITHIC_SHARED_LIBS))
   set(ABSL_BUILD_DLL TRUE)
   set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
 else()

ci/linux_gcc-latest_libstdcxx_cmake.sh

@@ -34,12 +34,23 @@ if [[ -z ${ABSL_CMAKE_BUILD_SHARED:-} ]]; then
   ABSL_CMAKE_BUILD_SHARED="OFF ON"
 fi
 
+if [[ -z ${ABSL_CMAKE_BUILD_MONOLITHIC_SHARED_LIBS:-} ]]; then
+  ABSL_CMAKE_BUILD_MONOLITHIC_SHARED_LIBS="OFF ON"
+fi
+
 source "${ABSEIL_ROOT}/ci/linux_docker_containers.sh"
 readonly DOCKER_CONTAINER=${LINUX_GCC_LATEST_CONTAINER}
 
 for std in ${ABSL_CMAKE_CXX_STANDARDS}; do
   for compilation_mode in ${ABSL_CMAKE_BUILD_TYPES}; do
     for build_shared in ${ABSL_CMAKE_BUILD_SHARED}; do
+      if [[ $build_shared == "OFF" ]]; then
+        monolithic_shared_options="OFF"
+      else
+        monolithic_shared_options="$ABSL_CMAKE_BUILD_MONOLITHIC_SHARED_LIBS"
+      fi
+
+      for monolithic_shared in $monolithic_shared_options; do
         time docker run \
           --mount type=bind,source="${ABSEIL_ROOT}",target=/abseil-cpp,readonly \
           --tmpfs=/buildfs:exec \
@@ -57,10 +68,12 @@ for std in ${ABSL_CMAKE_CXX_STANDARDS}; do
               -DABSL_BUILD_TESTING=ON \
               -DCMAKE_BUILD_TYPE=${compilation_mode} \
               -DCMAKE_CXX_STANDARD=${std} \
+              -DABSL_BUILD_MONOLITHIC_SHARED_LIBS=${monolithic_shared} \
               -DCMAKE_MODULE_LINKER_FLAGS=\"-Wl,--no-undefined\" && \
             make -j$(nproc) && \
             TZDIR=/abseil-cpp/absl/time/internal/cctz/testdata/zoneinfo \
             ctest -j$(nproc) --output-on-failure"
         done
     done
+  done
 done

ci/linux_gcc_alpine_cmake.sh

@@ -34,12 +34,23 @@ if [[ -z ${ABSL_CMAKE_BUILD_SHARED:-} ]]; then
   ABSL_CMAKE_BUILD_SHARED="OFF ON"
 fi
 
+if [[ -z ${ABSL_CMAKE_BUILD_MONOLITHIC_SHARED_LIBS:-} ]]; then
+  ABSL_CMAKE_BUILD_MONOLITHIC_SHARED_LIBS="OFF ON"
+fi
+
 source "${ABSEIL_ROOT}/ci/linux_docker_containers.sh"
 readonly DOCKER_CONTAINER=${LINUX_ALPINE_CONTAINER}
 
 for std in ${ABSL_CMAKE_CXX_STANDARDS}; do
   for compilation_mode in ${ABSL_CMAKE_BUILD_TYPES}; do
     for build_shared in ${ABSL_CMAKE_BUILD_SHARED}; do
+      if [[ $build_shared == "OFF" ]]; then
+        monolithic_shared_options="OFF"
+      else
+        monolithic_shared_options="$ABSL_CMAKE_BUILD_MONOLITHIC_SHARED_LIBS"
+      fi
+
+      for monolithic_shared in $monolithic_shared_options; do
         time docker run \
           --mount type=bind,source="${ABSEIL_ROOT}",target=/abseil-cpp,readonly \
           --tmpfs=/buildfs:exec \
@@ -53,13 +64,16 @@ for std in ${ABSL_CMAKE_CXX_STANDARDS}; do
           /bin/sh -c "
             cmake /abseil-cpp \
               -DABSL_GOOGLETEST_DOWNLOAD_URL=${ABSL_GOOGLETEST_DOWNLOAD_URL} \
+              -DBUILD_SHARED_LIBS=${build_shared} \
               -DABSL_BUILD_TESTING=ON \
               -DCMAKE_BUILD_TYPE=${compilation_mode} \
               -DCMAKE_CXX_STANDARD=${std} \
+              -DABSL_BUILD_MONOLITHIC_SHARED_LIBS=${monolithic_shared} \
               -DCMAKE_MODULE_LINKER_FLAGS=\"-Wl,--no-undefined\" && \
             make -j$(nproc) && \
             TZDIR=/abseil-cpp/absl/time/internal/cctz/testdata/zoneinfo \
             ctest -j$(nproc) --output-on-failure"
         done
     done
+  done
 done

ci/macos_xcode_cmake.sh

@@ -36,8 +36,19 @@ if [[ -z ${ABSL_CMAKE_BUILD_SHARED:-} ]]; then
   ABSL_CMAKE_BUILD_SHARED="OFF ON"
 fi
 
+if [[ -z ${ABSL_CMAKE_BUILD_MONOLITHIC_SHARED_LIBS:-} ]]; then
+  ABSL_CMAKE_BUILD_MONOLITHIC_SHARED_LIBS="OFF ON"
+fi
+
 for compilation_mode in ${ABSL_CMAKE_BUILD_TYPES}; do
   for build_shared in ${ABSL_CMAKE_BUILD_SHARED}; do
+    if [[ $build_shared == "OFF" ]]; then
+      monolithic_shared_options="OFF"
+    else
+      monolithic_shared_options="$ABSL_CMAKE_BUILD_MONOLITHIC_SHARED_LIBS"
+    fi
+
+    for monolithic_shared in $monolithic_shared_options; do
       BUILD_DIR=$(mktemp -d ${compilation_mode}.XXXXXXXX)
       cd ${BUILD_DIR}
 
@@ -49,9 +60,11 @@ for compilation_mode in ${ABSL_CMAKE_BUILD_TYPES}; do
         -DCMAKE_BUILD_TYPE=${compilation_mode} \
         -DCMAKE_CXX_STANDARD=14 \
         -DCMAKE_MODULE_LINKER_FLAGS="-Wl,--no-undefined" \
+        -DABSL_BUILD_MONOLITHIC_SHARED_LIBS=${monolithic_shared} \
         -DABSL_GOOGLETEST_DOWNLOAD_URL="${ABSL_GOOGLETEST_DOWNLOAD_URL}"
       time cmake --build .
       time TZDIR=${ABSEIL_ROOT}/absl/time/internal/cctz/testdata/zoneinfo \
         ctest -C ${compilation_mode} --output-on-failure
     done
+  done
 done