Merge pull request #200 from HappySeaFox/feature/openmp

Feature/openmp

.travis.yml

@@ -12,6 +12,7 @@ addons:
       - jpeg-turbo
       - jpeg-xl
       - libavif
+      - libomp
       - libpng
       - libtiff
       - webp
@@ -43,6 +44,7 @@ jobs:
       name: "macOS 12.6"
       env:
         - CMAKE_PREFIX_PATH="/usr/local/opt/jpeg-turbo;$CMAKE_PREFIX_PATH"
+        - OpenMP_ROOT=/usr/local/opt/libomp
 
 before_script:
 - |-
@@ -90,6 +92,7 @@ script:
     cd "$TRAVIS_BUILD_DIR"
 
     cd "$project_path"
+    rm -rf build
     mkdir build
     cd build
 
@@ -113,6 +116,7 @@ script:
     cd "$TRAVIS_BUILD_DIR"
 
     cd "$project_path"
+    rm -rf build
     mkdir build
     cd build
 

CMakeLists.txt

@@ -20,6 +20,7 @@ include(sail_check_builtin_bswap)
 include(sail_check_c11_thread_local)
 include(sail_check_include)
 include(sail_check_init_once_execute_once)
+include(sail_check_openmp)
 include(sail_codec)
 include(sail_enable_asan)
 include(sail_enable_pch)
@@ -77,6 +78,7 @@ endif()
 option(SAIL_BUILD_APPS "Build applications." ON)
 option(SAIL_BUILD_EXAMPLES "Build examples." ON)
 option(SAIL_DEV "Enable developer mode. Be more strict when compiling source code, for example." OFF)
+option(SAIL_ENABLE_OPENMP "Enable OpenMP support if it's available in the compiler." ON)
 set(SAIL_ENABLE_CODECS "" CACHE STRING "Forcefully enable the codecs specified in this ';'-separated list. \
 If an enabled codec fails to find its dependencies, the configuration process fails. \
 One can also specify not just individual codecs but codec groups by their priority like that: highest-priority;xbm. \
@@ -95,6 +97,12 @@ option(SAIL_THIRD_PARTY_CODECS_PATH "Enable loading third-party codecs from the
 the SAIL_THIRD_PARTY_CODECS_PATH environment variable." ON)
 option(SAIL_THREAD_SAFE "Enable working in multi-threaded environments by locking the internal context with a mutex." ON)
 
+if (SAIL_ENABLE_OPENMP)
+    sail_check_openmp()
+else()
+    set(SAIL_HAVE_OPENMP_DISPLAY "OFF (forced)" CACHE INTERNAL "")
+endif()
+
 # When we compile for VCPKG, VCPKG_TARGET_TRIPLET is defined
 #
 if (VCPKG_TARGET_TRIPLET)
@@ -327,6 +335,7 @@ message("*")
 message("* SAIL_HAVE_BUILTIN_BSWAP16:    ${SAIL_HAVE_BUILTIN_BSWAP16_DISPLAY}")
 message("* SAIL_HAVE_BUILTIN_BSWAP32:    ${SAIL_HAVE_BUILTIN_BSWAP32_DISPLAY}")
 message("* SAIL_HAVE_BUILTIN_BSWAP64:    ${SAIL_HAVE_BUILTIN_BSWAP64_DISPLAY}")
+message("* SAIL_HAVE_OPENMP:             ${SAIL_HAVE_OPENMP_DISPLAY}")
 message("*")
 message("* [*] - these options depend on other options, their values may be altered by CMake.")
 message("*       For example, if you configure with -DBUILD_SHARED_LIBS=OFF -DSAIL_COMBINE_CODECS=OFF,")

cmake/sail_check_openmp.cmake

@@ -0,0 +1,60 @@
+# Intended to be included by SAIL.
+#
+function(sail_check_openmp)
+    # This may require setting OpenMP_ROOT on macOS
+    #
+    find_package(OpenMP COMPONENTS C)
+
+    if (OpenMP_FOUND)
+        # We want OpenMP 3.0 to support unsigned integers in loops.
+        # The default OpenMP implementation in MSVC 2022 still supports 2.0,
+        # so switch to the LLVM option with OpenMP 3.1.
+        #
+        if (MSVC)
+            set(SAIL_OPENMP_FLAGS "/openmp:llvm" CACHE INTERNAL "")
+        else()
+            set(SAIL_OPENMP_FLAGS ${OpenMP_C_FLAGS} CACHE INTERNAL "")
+        endif()
+
+        set(SAIL_OPENMP_INCLUDE_DIRS ${OpenMP_C_INCLUDE_DIRS} CACHE INTERNAL "")
+
+        # Build a list of direct paths to libraries. This is needed on macOS with brew specifically
+        # as the installed libomp version lays in /usr/local/opt/libomp and is not globally visible.
+        #
+        foreach(lib IN LISTS OpenMP_C_LIB_NAMES)
+            set(SAIL_OPENMP_LIBS ${SAIL_OPENMP_LIBS} "${OpenMP_${lib}_LIBRARY}" CACHE INTERNAL "")
+        endforeach()
+
+        # Try to compile a sample program to make sure the compiler
+        # supports at least OpenMP 3.0 with unsigned integers in for loops.
+        #
+        cmake_push_check_state(RESET)
+            set(CMAKE_REQUIRED_FLAGS     ${SAIL_OPENMP_FLAGS})
+            set(CMAKE_REQUIRED_INCLUDES  ${SAIL_OPENMP_INCLUDE_DIRS})
+            set(CMAKE_REQUIRED_LIBRARIES ${SAIL_OPENMP_LIBS})
+
+            check_c_source_compiles(
+            "
+                #include <stdio.h>
+
+                int main(int argc, char *argv[]) {
+                    unsigned i;
+                    #pragma omp parallel for
+                    for (i = 0; i < 10; i++) {
+                        printf(\"%d\", i);
+                    }
+
+                    return 0;
+                }
+            "
+            SAIL_HAVE_OPENMP
+            )
+        cmake_pop_check_state()
+    endif()
+
+    if (SAIL_HAVE_OPENMP)
+        set(SAIL_HAVE_OPENMP_DISPLAY ON CACHE INTERNAL "")
+    else()
+        set(SAIL_HAVE_OPENMP_DISPLAY OFF CACHE INTERNAL "")
+    endif()
+endfunction()

src/sail-manip/CMakeLists.txt

@@ -38,6 +38,12 @@ endif()
 #
 target_include_directories(sail-manip PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/..>)
 
+if (SAIL_HAVE_OPENMP)
+    target_compile_options(sail-manip     PRIVATE ${SAIL_OPENMP_FLAGS})
+    target_include_directories(sail-manip PRIVATE ${SAIL_OPENMP_INCLUDE_DIRS})
+    target_link_libraries(sail-manip      PRIVATE ${SAIL_OPENMP_LIBS})
+endif()
+
 target_link_libraries(sail-manip PUBLIC sail-common)
 
 # pkg-config integration