Merge topic 'check_symbol_exists'

6856b4d Merge topic 'link-shared-depend-cycle-issue-12647' into check_symbol_exists
8e1f376 add a test for Check{,CXX}SymbolExists
813eca6 CheckSymbolExists: force the compiler to keep the referenced symbol

Modules/CheckSymbolExists.cmake

@@ -60,7 +60,7 @@ MACRO(_CHECK_SYMBOL_EXISTS SOURCEFILE SYMBOL FILES VARIABLE)
         "${CMAKE_CONFIGURABLE_FILE_CONTENT}#include <${FILE}>\n")
     ENDFOREACH(FILE)
     SET(CMAKE_CONFIGURABLE_FILE_CONTENT
-      "${CMAKE_CONFIGURABLE_FILE_CONTENT}\nvoid cmakeRequireSymbol(int dummy,...){(void)dummy;}\nint main()\n{\n#ifndef ${SYMBOL}\n  cmakeRequireSymbol(0,&${SYMBOL});\n#endif\n  return 0;\n}\n")
+      "${CMAKE_CONFIGURABLE_FILE_CONTENT}\nint main(int argc, char** argv)\n{\n  (void)argv;\n#ifndef ${SYMBOL}\n  return ((int*)(&${SYMBOL}))[argc];\n#else\n  (void)argc;\n  return 0;\n#endif\n}\n")
 
     CONFIGURE_FILE("${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in"
       "${SOURCEFILE}" @ONLY IMMEDIATE)

Tests/CMakeOnly/CMakeLists.txt

@@ -10,3 +10,7 @@ endmacro()
 
 add_CMakeOnly_test(LinkInterfaceLoop)
 set_property(TEST CMakeOnly.LinkInterfaceLoop PROPERTY TIMEOUT 90)
+
+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