add a test for Check{,CXX}SymbolExists

Now that we think that CheckSymbolExists really works for all cases it is time
to prove that. If this code fails too many other things will break.

Tests/CMakeOnly/CMakeLists.txt

@@ -7,3 +7,7 @@ macro(add_CMakeOnly_test test)
     -P ${CMAKE_CURRENT_BINARY_DIR}/Test.cmake
     )
 endmacro()
+
+add_CMakeOnly_test(CheckSymbolExists)
+
+add_CMakeOnly_test(CheckCXXSymbolExists)

Tests/CMakeOnly/CheckCXXSymbolExists/CMakeLists.txt

@@ -0,0 +1,62 @@
+# This test will verify if CheckCXXSymbolExists only report symbols available
+# for linking that really are. You can find some documentation on this in
+# bug 11333 where we found out that gcc would optimize out the actual
+# reference to the symbol, so symbols that are in fact _not_ available in the
+# given libraries (but seen in header) were reported as present.
+#
+# If you change this test do not forget to change the CheckSymbolExists
+# test, too.
+
+PROJECT(CheckCXXSymbolExists CXX)
+
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
+
+SET(CMAKE_REQUIRED_INCLUDES "${CMAKE_CURRENT_SOURCE_DIR}/../CheckSymbolExists")
+
+INCLUDE(CheckCXXSymbolExists)
+
+foreach(_config_type Release RelWithDebInfo MinSizeRel Debug)
+  set(CMAKE_TRY_COMPILE_CONFIGURATION ${_config_type})
+  unset(CSE_RESULT_${_config_type} CACHE)
+  MESSAGE(STATUS "Testing configuration ${_config_type}")
+  check_cxx_symbol_exists(non_existent_function_for_symbol_test "cm_cse.h" CSE_RESULT_${_config_type})
+
+  IF (CSE_RESULT_${_config_type})
+    MESSAGE(SEND_ERROR "CheckCXXSymbolExists reported a nonexistent symbol as existing in configuration ${_config_type}")
+  ENDIF (CSE_RESULT_${_config_type})
+endforeach()
+
+set(CMAKE_TRY_COMPILE_CONFIGURATION ${CMAKE_BUILD_TYPE})
+unset(CSE_RESULT_ERRNO_CERRNO CACHE)
+
+MESSAGE(STATUS "Checking <cerrno>")
+
+check_cxx_symbol_exists(errno "cerrno" CSE_RESULT_ERRNO_CERRNO)
+
+IF (NOT CSE_RESULT_ERRNO_CERRNO)
+  unset(CSE_RESULT_ERRNO_ERRNOH CACHE)
+
+  MESSAGE(STATUS "Checking <errno.h>")
+
+  check_cxx_symbol_exists(errno "errno.h" CSE_RESULT_ERRNO_ERRNOH)
+
+  IF (NOT CSE_RESULT_ERRNO_ERRNOH)
+    MESSAGE(SEND_ERROR "CheckCXXSymbolExists did not find errno in <cerrno> and <errno.h>")
+  ELSE (NOT CSE_RESULT_ERRNO_ERRNOH)
+    MESSAGE(STATUS "errno found in <errno.h>")
+  ENDIF (NOT CSE_RESULT_ERRNO_ERRNOH)
+ELSE (NOT CSE_RESULT_ERRNO_CERRNO)
+  MESSAGE(STATUS "errno found in <cerrno>")
+ENDIF (NOT CSE_RESULT_ERRNO_CERRNO)
+
+IF (CMAKE_COMPILER_IS_GNUCXX)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3")
+  unset(CSE_RESULT_O3 CACHE)
+  MESSAGE(STATUS "Testing with optimization -O3")
+
+  check_cxx_symbol_exists(non_existent_function_for_symbol_test "cm_cse.h" CSE_RESULT_O3)
+
+  IF (CSE_RESULT_O3)
+    MESSAGE(SEND_ERROR "CheckCXXSymbolExists reported a nonexistent symbol as existing with optimization -O3")
+  ENDIF (CSE_RESULT_O3)
+ENDIF (CMAKE_COMPILER_IS_GNUCXX)

Tests/CMakeOnly/CheckSymbolExists/CMakeLists.txt

@@ -0,0 +1,51 @@
+# This test will verify if CheckSymbolExists only report symbols available
+# for linking that really are. You can find some documentation on this in
+# bug 11333 where we found out that gcc would optimize out the actual
+# reference to the symbol, so symbols that are in fact _not_ available in the
+# given libraries (but seen in header) were reported as present.
+#
+# If you change this test do not forget to change the CheckCXXSymbolExists
+# test, too.
+
+PROJECT(CheckSymbolExists C)
+
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
+
+SET(CMAKE_REQUIRED_INCLUDES "${CMAKE_CURRENT_SOURCE_DIR}")
+
+INCLUDE(CheckSymbolExists)
+
+foreach(_config_type Release RelWithDebInfo MinSizeRel Debug)
+  set(CMAKE_TRY_COMPILE_CONFIGURATION ${_config_type})
+  unset(CSE_RESULT_${_config_type} CACHE)
+  MESSAGE(STATUS "Testing configuration ${_config_type}")
+
+  check_symbol_exists(non_existent_function_for_symbol_test "cm_cse.h" CSE_RESULT_${_config_type})
+
+  IF (CSE_RESULT_${_config_type})
+    MESSAGE(SEND_ERROR "CheckSymbolExists reported a nonexistent symbol as existing in configuration ${_config_type}")
+  ENDIF (CSE_RESULT_${_config_type})
+endforeach()
+
+set(CMAKE_TRY_COMPILE_CONFIGURATION ${CMAKE_BUILD_TYPE})
+unset(CSE_RESULT_ERRNO CACHE)
+
+check_symbol_exists(errno "errno.h" CSE_RESULT_ERRNO)
+
+IF (NOT CSE_RESULT_ERRNO)
+  MESSAGE(SEND_ERROR "CheckSymbolExists did not find errno in <errno.h>")
+ELSE (NOT CSE_RESULT_ERRNO)
+  MESSAGE(STATUS "errno found as expected")
+ENDIF (NOT CSE_RESULT_ERRNO)
+
+IF (CMAKE_COMPILER_IS_GNUCC)
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O3")
+  unset(CSE_RESULT_O3 CACHE)
+  MESSAGE(STATUS "Testing with optimization -O3")
+
+  check_symbol_exists(non_existent_function_for_symbol_test "cm_cse.h" CSE_RESULT_O3)
+
+  IF (CSE_RESULT_O3)
+    MESSAGE(SEND_ERROR "CheckSymbolExists reported a nonexistent symbol as existing with optimization -O3")
+  ENDIF (CSE_RESULT_O3)
+ENDIF (CMAKE_COMPILER_IS_GNUCC)

Tests/CMakeOnly/CheckSymbolExists/cm_cse.h

@@ -0,0 +1,6 @@
+#ifndef _CSE_DUMMY_H
+#define _CSE_DUMMY_H
+
+int non_existent_function_for_symbol_test();
+
+#endif