[MacPorts] #40648: cmake @2.8.11.2 does not set optimization flags in release

[MacPorts]

#40648: cmake @2.8.11.2 does not set optimization flags in release
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  Reporter:  macports@…  |      Owner:  css@…
      Type:  defect      |     Status:  assigned
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:
Resolution:              |   Keywords:
      Port:  cmake       |
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Comment (by Torsten.Maehne@…):

 As a regular CMake user, I'm also affected by this annoying issue.
 Therefore, I had a look to the CMake port group to fix the issue with the
 following uploaded patches:

 {{{0001-Fix-the-CMake-port-specific-part-of-ticket-40648.patch}}}

 Fix the CMake-port-specific part of this ticket.

 This reverts the changes made to the CMake Portfile in r110069 so that
 ports, which are configured by CMake, honor the configure.optflags set
 in the Portfile. Thus, Release builds are compiled with optimization
 by default again.

 {{{0002-Improve-CMake-PortGroup-to-handle-the-configure-flags.patch}}}

 Improve the CMake PortGroup so that it handles the configure.*flags.

 The configure.cppflags, configure.optflags, configure.cflags,
 configure.cxxflags, configure.ldflags are handled by setting the
 equivalent CMAKE_*_FLAGS.

 The configure.cppflags are added to the C/C++ compiler flags as CMake
 does not honor separately CPPFLAGS (it uses usually add_definitions()
 for that). The compiler flags for all build types (CMAKE_C_FLAGS,
 CMAKE_CXX_FLAGS) are used, as they are usually empty. Cf. also to
 CMake upstream ticket #12928 "CMake silently ignores CPPFLAGS"
 <http://www.cmake.org/Bug/view.php?id=12928>.

 The configure.cflags contain configure.optflags by default. Therefore,
 they are set via the Release flags CMAKE_C_FLAGS_RELEASE, which would
 otherwise overrule the optimization flags, as they are set by default
 to "-O3 -NDEBUG". Therefore, be sure to add "-NDEBUG" to the
 configure.cflags if you want to turn off assertions in release builds!

 The configure.cxxflags contain configure.optflags by
 default. Therefore, they are set via the Release flags
 CMAKE_CXX_FLAGS_RELEASE, which would otherwise overrule the
 optimization flags, as they are set by default to "-O3
 -NDEBUG". Therefore, be sure to add "-NDEBUG" to the configure.cflags
 if you want to turn off assertions in release builds!

 A port author has to be aware that a CMake script can always override
 these flags when it runs, as they are frequently set internally in
 function of other CMake build variables!

 Attention: If the port author wants to be sure that no compiler flags
 are passed via configure.args to CMake, he has to set manually
 configure.optflags to "", as it is by default "-O2" and added to all
 language-specific flags. If he wants to prevent optimization, he
 should set configure.optflags to "-O0".

 TODO: Handle the compiler flags specific to Objective-C, Fortran, and
 Java in the CMake PortGroup.

 This patch does not fix the issue in the case of selecting the +debug
 variant of the CMake PortGroup for which two additional patches are
 necessary:

 {{{0003-Fix-CMake-PortGroup-debug-variant.patch}}}

 Change the CMAKE_BUILD_TYPE to Debug instead of debugFull for the +debug
 variant in the CMake PortGroup.

 "debugFull" is not a standard build type in CMake so there are no
 default compiler flags set for it, which would turn on the inclusion
 of debug symbols. Instead, CMake provides the build type "Debug" for
 this purpose. Only KDE provides in its CMake build infrastructure
 support for a build type called "DebugFull", which turns off
 optimization, as KDE leaves it on for the "Debug" build type. Confer
 to <http://techbase.kde.org/Development/CMake/Addons_for_KDE> for
 further explanations.

 {{{0004-Handle-configure.cflags-and-configure.cxxflags-in-debug-variant-
 of-CMake-PortGroup.patch}}}

 Consider the configure.cflags and configure.cxxflags for +debug variant of
 the CMake PortsGroup.

 The CMAKE_BUILD_TYPE "Debug" uses CMAKE_C_FLAGS_DEBUG and
 CMAKE_CXX_FLAGS_DEBUG to specify the compiler flags. These variables
 are set to "-g" plus the respective configure.cflags and
 configure.cxxflags. Be aware that configure.cflags and
 configure.cxxflags contain configure.optflags by default, which are
 not deleted for the Debug build. The port author has to set
 configure.optflags to "-O0" to turn off optimization.

 Please have a look on it and test it with the ports, which motivated the
 change in r110069 in the first place. I don't have commit rights to apply
 these changes to the MacPorts SVN.

-- 
Ticket URL: <https://trac.macports.org/ticket/40648#comment:15>
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