openmp: new meta-package

recipes/openmp/all/conanfile.py

@@ -0,0 +1,89 @@
+from conan import ConanFile
+from conan.errors import ConanInvalidConfiguration
+from conan.tools.microsoft import is_msvc
+
+required_conan_version = ">=1.52.0"
+
+
+class PackageConan(ConanFile):
+    name = "openmp"
+    version = "cci.latest"
+    description = "Conan meta-package for OpenMP (Open Multi-Processing)"
+    license = "MIT"
+    url = "https://github.com/conan-io/conan-center-index"
+    homepage = "https://www.openmp.org/"
+    topics = ("parallelism", "multiprocessing")
+
+    package_type = "header-library"
+    settings = "os", "arch", "compiler", "build_type"
+    options = {
+        "provider": ["auto", "llvm-openmp"],
+    }
+    default_options = {
+        "provider": "auto",
+    }
+
+    def config_options(self):
+        # GCC and MSVC provide OpenMP out of the box, use llvm-openmp from CCI for others
+        if self.settings.compiler != "gcc" and not is_msvc(self):
+            self.options.provider = "llvm-openmp"
+
+    def layout(self):
+        pass
+
+    def requirements(self):
+        if self.options.provider == "llvm-openmp":
+            self.requires("llvm-openmp/17.0.6", transitive_headers=True, transitive_libs=True)
+
+    def package_id(self):
+        self.info.clear()
+
+    def validate(self):
+        if is_msvc(self) and self.options.provider == "llvm-openmp":
+            raise ConanInvalidConfiguration("llvm-openmp is not compatible with MSVC")
+        if not self._openmp_flags():
+            raise ConanInvalidConfiguration(
+                f"{self.settings.compiler} is not supported by this recipe. Contributions are welcome!"
+            )
+
+    def source(self):
+        pass
+
+    def build(self):
+        pass
+
+    def package(self):
+        pass
+
+    def _openmp_flags(self):
+        # Based on https://github.com/Kitware/CMake/blob/v3.28.1/Modules/FindOpenMP.cmake#L104-L135
+        if self.settings.compiler == "clang":
+            return ["-fopenmp=libomp"]
+        elif self.settings.compiler == "apple-clang":
+            return ["-Xclang", "-fopenmp"]
+        elif self.settings.compiler == "gcc":
+            return ["-fopenmp"]
+        elif self.settings.compiler == "intel-cc":
+            return ["-Qopenmp"]
+        elif self.settings.compiler == "sun-cc":
+            return ["-xopenmp"]
+        elif is_msvc(self):
+            return ["-openmp"]
+        return None
+
+    def package_info(self):
+        self.cpp_info.set_property("cmake_find_mode", "none")
+
+        self.cpp_info.frameworkdirs = []
+        self.cpp_info.libdirs = []
+        self.cpp_info.resdirs = []
+        self.cpp_info.includedirs = []
+
+        if self.options.provider == "auto":
+            # Rely on CMake's FindOpenMP.cmake and an OpenMP implementation provided by the compiler.
+            # Export appropriate flags for the transitive use case.
+            openmp_flags = self._openmp_flags()
+            self.cpp_info.sharedlinkflags = openmp_flags
+            self.cpp_info.exelinkflags = openmp_flags
+            self.cpp_info.cflags = openmp_flags
+            self.cpp_info.cxxflags = openmp_flags

recipes/openmp/all/test_package/CMakeLists.txt

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.15)
+project(PackageTest CXX C)
+
+find_package(OpenMP MODULE REQUIRED)
+
+message("OpenMP_FOUND: ${OpenMP_CXX_FOUND}")
+message("OpenMP_CXX_FOUND: ${OpenMP_CXX_FOUND}")
+message("OpenMP_CXX_VERSION: ${OpenMP_CXX_VERSION}")
+message("OpenMP_CXX_SPEC_DATE: ${OpenMP_CXX_SPEC_DATE}")
+message("OpenMP_CXX_INCLUDE_DIRS: ${OpenMP_CXX_INCLUDE_DIRS}")
+message("OpenMP_INCLUDE_DIRS: ${OpenMP_CXX_INCLUDE_DIRS}")
+
+if(NOT DEFINED OpenMP_C_INCLUDE_DIRS)
+    message(FATAL_ERROR "OpenMP_C_INCLUDE_DIRS is not defined")
+endif()
+if(NOT DEFINED OpenMP_CXX_INCLUDE_DIRS)
+    message(FATAL_ERROR "OpenMP_CXX_INCLUDE_DIRS is not defined")
+endif()
+
+add_executable(test_package_cxx test_package.cpp)
+target_link_libraries(test_package_cxx OpenMP::OpenMP_CXX)
+
+add_executable(test_package_c test_package.c)
+target_link_libraries(test_package_c OpenMP::OpenMP_C)

recipes/openmp/all/test_package/conanfile.py

@@ -0,0 +1,27 @@
+from conan import ConanFile
+from conan.tools.build import can_run
+from conan.tools.cmake import cmake_layout, CMake
+import os
+
+
+class TestPackageConan(ConanFile):
+    settings = "os", "arch", "compiler", "build_type"
+    generators = "CMakeDeps", "CMakeToolchain", "VirtualRunEnv"
+    test_type = "explicit"
+
+    def requirements(self):
+        self.requires(self.tested_reference_str)
+
+    def layout(self):
+        cmake_layout(self)
+
+    def build(self):
+        cmake = CMake(self)
+        cmake.configure()
+        cmake.build()
+
+    def test(self):
+        if can_run(self):
+            for executable in ["test_package_cxx", "test_package_c"]:
+                bin_path = os.path.join(self.cpp.build.bindir, executable)
+                self.run(bin_path, env="conanrun")

recipes/openmp/all/test_package/test_package.c

@@ -0,0 +1,26 @@
+#include <omp.h>
+
+#include <stdio.h>
+
+int main()
+{
+    int num_threads = omp_get_num_procs();
+    if (num_threads < 5)
+        num_threads = 5;
+    omp_set_num_threads(num_threads);
+    int actual_number;
+    #pragma omp parallel
+    {
+       #pragma omp single
+       {
+          actual_number = omp_get_num_threads();
+       }
+    }
+    if(actual_number != num_threads){
+        printf("Something went wrong. Expecting %d threads but found %d.\n", num_threads, actual_number);
+        printf("There are probably missing compiler flags.\n");
+        return 1;
+    }
+    printf("OpenMP year-month version: %d", _OPENMP);
+    return 0;
+}

recipes/openmp/all/test_package/test_package.cpp

@@ -0,0 +1,24 @@
+#include <omp.h>
+
+#include <iostream>
+
+int main()
+{
+    int num_threads = std::max(5, omp_get_num_procs());
+    omp_set_num_threads(num_threads);
+    int actual_number;
+    #pragma omp parallel
+    {
+       #pragma omp single
+       {
+          actual_number = omp_get_num_threads();
+       }
+    }
+    if(actual_number != num_threads){
+        std::cout << "Something went wrong. Expecting " << num_threads << " threads but found " << actual_number << ".\n";
+        std::cout << "There are probably missing compiler flags.\n";
+        return 1;
+    }
+    std::cout << "OpenMP year-month version: " << _OPENMP << "\n";
+    return 0;
+}

recipes/openmp/config.yml

@@ -0,0 +1,3 @@
+versions:
+  "cci.latest":
+    folder: all