CMake: Bugfix: Correctly detect unsupported flags in case of clang

The clang compiler frontend is very conservative in not issuing an error
for unsupported compile flags but that are valid for gcc. Therefore, also
supply "-Werror" for the clang compiler in all 'ENABLE_IF_SUPPORTED' tests.

diff --git a/cmake/checks/check_01_compiler_features.cmake b/cmake/checks/check_01_compiler_features.cmake
index e9856af06385fa1f93990f1fbf508a09a9fab7e3..a1fc8c1ac36174137295a00683a8c454298b0c58 100644 (file)
--- a/cmake/checks/check_01_compiler_features.cmake
+++ b/cmake/checks/check_01_compiler_features.cmake
@@ -1,6 +1,6 @@
 ## ---------------------------------------------------------------------
 ##
-## Copyright (C) 2012 - 2013 by the deal.II authors
+## Copyright (C) 2012 - 2014 by the deal.II authors
 ##
 ## This file is part of the deal.II library.
 ##
@@ -152,7 +152,7 @@ CHECK_CXX_SOURCE_COMPILES(
   HAVE_GLIBC_STACKTRACE)
 
 IF(HAVE_GLIBC_STACKTRACE AND NOT DEAL_II_STATIC_EXECUTABLE)
-  ENABLE_IF_SUPPORTED(DEAL_II_LINKER_FLAGS "-rdynamic")
+  ENABLE_IF_LINKS(DEAL_II_LINKER_FLAGS "-rdynamic")
 ENDIF()
 
 

diff --git a/cmake/macros/macro_enable_if_supported.cmake b/cmake/macros/macro_enable_if_supported.cmake
index 325ae83ecd0184a00631902f5ea90b4770816787..198d90a8e39afe86eaccbfbfc5b843cd827501e4 100644 (file)
--- a/cmake/macros/macro_enable_if_supported.cmake
+++ b/cmake/macros/macro_enable_if_supported.cmake
@@ -22,6 +22,17 @@
 #
 
 MACRO(ENABLE_IF_SUPPORTED _variable _flag)
+  #
+  # Clang is too conservative when reporting unsupported compiler flags.
+  # Therefore, we promote all warnings for an unsupported compiler flag to
+  # actual errors with the -Werror switch:
+  #
+  IF(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    SET(_werror_string "-Werror ")
+  ELSE()
+    SET(_werror_string "")
+  ENDIF()
+
   STRING(STRIP "${_flag}" _flag_stripped)
   IF(NOT "${_flag_stripped}" STREQUAL "")
     STRING(REGEX REPLACE "^-" "" _flag_name "${_flag_stripped}")
@@ -29,7 +40,7 @@ MACRO(ENABLE_IF_SUPPORTED _variable _flag)
     STRING(REPLACE "-" "_" _flag_name "${_flag_name}")
     STRING(REPLACE "++" "__" _flag_name "${_flag_name}")
     CHECK_CXX_COMPILER_FLAG(
-      "${_flag_stripped}"
+      "${_werror_string}${_flag_stripped}"
       DEAL_II_HAVE_FLAG_${_flag_name}
       )
     IF(DEAL_II_HAVE_FLAG_${_flag_name})