From: Matthias Maier Date: Thu, 11 Dec 2014 19:49:34 +0000 (+0100) Subject: CMake: Correctly detect -Wno-... support for gcc X-Git-Tag: v8.2.0-rc1~19^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F297%2Fhead;p=dealii.git CMake: Correctly detect -Wno-... support for gcc gcc does not emit a warning if an unknown -Wno-... flag is specified on the command line, thus the ENABLE_IF_SUPPORTED macro unconditionally enabled -Wno-... flags for gcc. Unfortunately, gcc _does_ emit a warning for the unrecognized compiler option if another warning is emitted in the same compilation unit. This is now fixed by always querying for the non-negated version, i.e. -Wfoo instead of -Wno-foo. --- diff --git a/cmake/macros/macro_enable_if_supported.cmake b/cmake/macros/macro_enable_if_supported.cmake index 1485fb57df..d84b2d98bb 100644 --- a/cmake/macros/macro_enable_if_supported.cmake +++ b/cmake/macros/macro_enable_if_supported.cmake @@ -34,6 +34,19 @@ MACRO(ENABLE_IF_SUPPORTED _variable _flag) ENDIF() STRING(STRIP "${_flag}" _flag_stripped) + SET(_flag_stripped_orig "${_flag_stripped}") + + # + # Gcc does not emit a warning if testing -Wno-... flags which leads to + # false positive detection. Unfortunately it later warns that an unknown + # warning option is used if another warning is emited in the same + # compilation unit. + # Therefore we invert the test for -Wno-... flags: + # + IF(CMAKE_CXX_COMPILER_ID MATCHES "GNU") + STRING(REPLACE "-Wno-" "-W" _flag_stripped "${_flag_stripped}") + ENDIF() + IF(NOT "${_flag_stripped}" STREQUAL "") STRING(REGEX REPLACE "^-" "" _flag_name "${_flag_stripped}") STRING(REPLACE "," "" _flag_name "${_flag_name}") @@ -44,7 +57,7 @@ MACRO(ENABLE_IF_SUPPORTED _variable _flag) DEAL_II_HAVE_FLAG_${_flag_name} ) IF(DEAL_II_HAVE_FLAG_${_flag_name}) - SET(${_variable} "${${_variable}} ${_flag_stripped}") + SET(${_variable} "${${_variable}} ${_flag_stripped_orig}") STRING(STRIP "${${_variable}}" ${_variable}) ENDIF() ENDIF() diff --git a/doc/news/changes.h b/doc/news/changes.h index abe13a6a80..1ad9462892 100644 --- a/doc/news/changes.h +++ b/doc/news/changes.h @@ -340,6 +340,11 @@ inconvenience this causes.

Specific improvements

    +
  1. Fixed: CMake now correctly detects -Wno-... support for gcc. +
    + (Matthias Maier, 2014/12/11) +
  2. +
  3. New: The FE_Q and FE_Q_Hierarchical classes now include pictures of their 2d shape functions in the class documentation.