Link profiling libraries for coverage builds (hyrise#2499)

src/CMakeLists.txt

@@ -31,6 +31,7 @@ if (${ENABLE_COVERAGE})
         set(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} --coverage")
     elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
         add_compile_options(-fprofile-instr-generate -fcoverage-mapping)
+        add_link_options(-fprofile-instr-generate -fcoverage-mapping)
         set(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} -fprofile-instr-generate -fcoverage-mapping")
     else()
         message(FATAL_ERROR "Don't know how to run coverage on your compiler (${CMAKE_CXX_COMPILER_ID}).")

src/lib/CMakeLists.txt

@@ -557,6 +557,7 @@ set(
     types.cpp
     types.hpp
     uid_allocator.hpp
+    utils/abstract_plugin.cpp
     utils/abstract_plugin.hpp
     utils/aligned_size.hpp
     utils/assert.hpp

src/lib/utils/abstract_plugin.cpp

@@ -0,0 +1,13 @@
+#include "abstract_plugin.hpp"
+
+namespace hyrise {
+
+// We have to instantiate this function here because clang-12(+) does not instantiate it and llvm-cov throws a warning
+// (functions have mismatched data). See
+// https://stackoverflow.com/questions/57331600/llvm-cov-statistics-for-uninstantiated-functions
+std::vector<std::pair<PluginFunctionName, PluginFunctionPointer>> AbstractPlugin::provided_user_executable_functions()
+    const {
+  return {};
+}
+
+}  // namespace hyrise

src/lib/utils/abstract_plugin.hpp

@@ -9,8 +9,10 @@ namespace hyrise {
 
 // This is necessary to make the plugin instantiable, it leads to plain C linkage to avoid
 // ugly mangled names. Use EXPORT in the implementation file of your plugin.
-#define EXPORT_PLUGIN(PluginName) \
-  extern "C" AbstractPlugin* factory() { return new PluginName(); }
+#define EXPORT_PLUGIN(PluginName)        \
+  extern "C" AbstractPlugin* factory() { \
+    return new PluginName();             \
+  }
 
 using PluginFunctionName = std::string;
 using PluginFunctionPointer = std::function<void(void)>;
@@ -34,9 +36,7 @@ class AbstractPlugin {
   // exec_user_function method. If you are writing a plugin and provide user-exectuable functions it
   // is YOUR responsibility to keep these function calls as short and efficient as possible, e.g.,
   // by spinning up a thread inside the plugin to execute the actual functionality.
-  virtual std::vector<std::pair<PluginFunctionName, PluginFunctionPointer>> provided_user_executable_functions() const {
-    return {};
-  }
+  virtual std::vector<std::pair<PluginFunctionName, PluginFunctionPointer>> provided_user_executable_functions() const;
 };
 
 }  // namespace hyrise