Filter for target types and no-visibility option

IMPORTED and ALIAS targets cannot be add to coverage.
Also, in old project where PUBLIC, PRIVATE or INTERFACE visibility
was not specified on target, there is option PLAIN which do not
set any for compile and link (this requires PUBLIC) option.

Author: rlalik

code-coverage.cmake

@@ -208,17 +208,39 @@ if(CODE_COVERAGE AND NOT CODE_COVERAGE_ADDED)
     if (COMMAND _add_executable)
       message(FATAL_ERROR "add_executable was already redefined. Only one redefinitions is allowed.")
     endif()
-    macro(add_executable)
-      _add_executable(${ARGV})
-      target_code_coverage(${ARGV0} ${CCOV_TARGETS_HOOK_ARGS})
+
+    set(CCOV_TARGETS_HOOK_LIST ${CCOV_TARGETS_HOOK_ARGS})
+    separate_arguments(CCOV_TARGETS_HOOK_LIST)
+
+    macro(add_executable target_name)
+      _add_executable(${target_name} ${ARGN})
+      if (${ARGC} GREATER 1)
+        string(TOUPPER ${ARGV1} TARGET_TYPE)
+      endif()
+      string(COMPARE NOTEQUAL "${TARGET_TYPE}" IMPORTED IS_NOT_IMPORTED)
+
+      if (IS_NOT_IMPORTED)
+          target_code_coverage(${target_name} ${CCOV_TARGETS_HOOK_LIST})
+      endif()
     endmacro(add_executable)
 
     if (COMMAND _add_library)
       message(FATAL_ERROR "add_library was already redefined. Only one redefinitions is allowed.")
     endif()
-    macro(add_library)
-      _add_library(${ARGV})
-      target_code_coverage(${ARGV0} ${CCOV_TARGETS_HOOK_ARGS})
+    macro(add_library target_name)
+      _add_library(${target_name} ${ARGN})
+      if (${ARGC} GREATER 1)
+        string(TOUPPER "${ARGV1}" TARGET_TYPE)
+      endif()
+      if (${ARGC} GREATER 2)
+        string(TOUPPER "${ARGV2}" IMPORTED_TYPE)
+      endif()
+      string(COMPARE NOTEQUAL "${TARGET_TYPE}" ALIAS IS_NOT_ALIAS)
+      string(COMPARE NOTEQUAL "${IMPORTED_TYPE}" IMPORTED IS_NOT_IMPORTED)
+
+      if (IS_NOT_ALIAS AND IS_NOT_IMPORTED)
+        target_code_coverage(${target_name} ${CCOV_TARGETS_HOOK_LIST})
+      endif()
     endmacro(add_library)
   endif (CCOV_TARGETS_HOOK)
 
@@ -249,6 +271,7 @@ endif()
 # Optional:
 # PUBLIC - Sets the visibility for added compile options to targets to PUBLIC instead of the default of PRIVATE.
 # INTERFACE - Sets the visibility for added compile options to targets to INTERFACE instead of the default of PRIVATE.
+# PLAIN - Do not set any target visibility (backward compatibility with old cmake projects)
 # AUTO - Adds the target to the 'ccov' target so that it can be run in a batch with others easily. Effective on executable targets.
 # ALL - Adds the target to the 'ccov-all' and 'ccov-all-report' targets, which merge several executable targets coverage data to a single report. Effective on executable targets.
 # EXTERNAL - For GCC's lcov, allows the profiling of 'external' files from the processing directory
@@ -259,7 +282,7 @@ endif()
 # ~~~
 function(target_code_coverage TARGET_NAME)
   # Argument parsing
-  set(options AUTO ALL EXTERNAL PUBLIC INTERFACE)
+  set(options AUTO ALL EXTERNAL PUBLIC INTERFACE PLAIN)
   set(single_value_keywords COVERAGE_TARGET_NAME)
   set(multi_value_keywords EXCLUDE OBJECTS ARGS)
   cmake_parse_arguments(
@@ -270,10 +293,16 @@ function(target_code_coverage TARGET_NAME)
   # PRIVATE.
   if(target_code_coverage_PUBLIC)
     set(TARGET_VISIBILITY PUBLIC)
+    set(TARGET_LINK_VISIBILITY PUBLIC)
   elseif(target_code_coverage_INTERFACE)
     set(TARGET_VISIBILITY INTERFACE)
+    set(TARGET_LINK_VISIBILITY INTERFACE)
+  elseif(target_code_coverage_PLAIN)
+    set(TARGET_VISIBILITY PUBLIC)
+    set(TARGET_LINK_VISIBILITY)
   else()
     set(TARGET_VISIBILITY PRIVATE)
+    set(TARGET_LINK_VISIBILITY PRIVATE)
   endif()
 
   if(NOT target_code_coverage_COVERAGE_TARGET_NAME)
@@ -294,7 +323,7 @@ function(target_code_coverage TARGET_NAME)
                                                 "GNU")
       target_compile_options(${TARGET_NAME} ${TARGET_VISIBILITY} -fprofile-arcs
                              -ftest-coverage)
-      target_link_libraries(${TARGET_NAME} ${TARGET_VISIBILITY} gcov)
+      target_link_libraries(${TARGET_NAME} ${TARGET_LINK_VISIBILITY} gcov)
     endif()
 
     # Targets