cmake: Modernize compile settings; require C++14

Clean up QuasselCompileSettings.cmake, treat GNU and Clang the same.
Use add_compile_options() instead of CMAKE_CXX_FLAGS. Curate the list
of compiler flags, and add sensible linker flags, too.

Check explicitly for required compiler features using CMake's
target_compile_features(), rather than hard-coding compiler versions.
The set of required features basically implies that we now require
a C++14 compiler (even though the new stuff isn't used in the code
yet).

diff --git a/INSTALL b/INSTALL
index 03abd3e..2de2f75 100644 (file)
--- a/INSTALL
+++ b/INSTALL
@@ -23,14 +23,15 @@ Prerequisites
 -------------
 
 Of course, for building Quassel you need the usual set of build tools, for
 -------------
 
 Of course, for building Quassel you need the usual set of build tools, for

-example a compiler. As we use a subset of the C++11 standard, we require a
-fairly recent compiler:
-
-- gcc 4.8+ (available for most platforms), or
-- Clang 3.3+ (available for most platforms), or
-- XCode 5.0+ (available for Max OS X and based on Clang), or
-- Visual C++ 2015 (available for Windows™), or
-- any other compiler with decent C++11 support
+example a compiler. The codebase uses the C++14 standard, so a reasonably recent
+compiler is needed:
+
+- GCC 5.0+ (available for most platforms), or
+- Clang 3.4+ (available for most platforms), or
+- XCode 6.0+ (available for Max OS X and based on Clang), or
+- MSVC 19+ (part of Visual Studio 2017 on Windows™)
+
+Other compilers may work, but are not officially supported.

 
 Furthermore, CMake 3.5 or later is required.
 
 
 Furthermore, CMake 3.5 or later is required.
 

diff --git a/cmake/QuasselCompileFeatures.cmake b/cmake/QuasselCompileFeatures.cmake
new file mode 100644 (file)
index 0000000..48faef5
--- /dev/null
+++ b/cmake/QuasselCompileFeatures.cmake
@@ -0,0 +1,39 @@
+# The compile(r) features required to build the Quassel source.
+# This list is used by CMake to determine if the compiler can build the code.
+set(QUASSEL_COMPILE_FEATURES
+    cxx_aggregate_default_initializers
+    cxx_alias_templates
+    cxx_constexpr
+    cxx_decltype
+    cxx_default_function_template_args
+    cxx_defaulted_functions
+    cxx_defaulted_move_initializers
+    cxx_delegating_constructors
+    cxx_deleted_functions
+    cxx_enum_forward_declarations
+    cxx_explicit_conversions
+    cxx_final
+    cxx_generalized_initializers
+    cxx_generic_lambdas
+    cxx_inheriting_constructors
+    cxx_lambdas
+    cxx_lambda_init_captures
+    cxx_noexcept
+    cxx_nonstatic_member_init
+    cxx_nullptr
+    cxx_override
+    cxx_range_for
+    cxx_raw_string_literals
+    cxx_return_type_deduction
+    cxx_right_angle_brackets
+    cxx_rvalue_references
+    cxx_static_assert
+    cxx_strong_enums
+    cxx_thread_local
+    cxx_trailing_return_types
+    cxx_uniform_initialization
+    cxx_user_literals
+    cxx_variadic_macros
+    cxx_variadic_templates
+    cxx_template_template_parameters
+)

diff --git a/cmake/QuasselCompileSettings.cmake b/cmake/QuasselCompileSettings.cmake
index 7d6f71a..ec3e17a 100644 (file)
--- a/cmake/QuasselCompileSettings.cmake
+++ b/cmake/QuasselCompileSettings.cmake
@@ -1,62 +1,63 @@
 # This file contains compile flags and general build configuration for Quassel
 #
 # This file contains compile flags and general build configuration for Quassel
 #

-# (C) 2014 by the Quassel Project <devel@quassel-irc.org>
+# (C) 2014-2018 by the Quassel Project <devel@quassel-irc.org>

 #
 # Redistribution and use is allowed according to the terms of the BSD license.
 # For details see the accompanying COPYING-CMAKE-SCRIPTS file.
 
 #
 # Redistribution and use is allowed according to the terms of the BSD license.
 # For details see the accompanying COPYING-CMAKE-SCRIPTS file.
 

+# Helper function to check for linker flag support

 include(CheckCXXCompilerFlag)
 include(CheckCXXCompilerFlag)

-
-# Enable various flags on gcc
-if (CMAKE_COMPILER_IS_GNUCXX)
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "4.8")
-        message(FATAL_ERROR "Your compiler is too old; you need GCC 4.8+, Clang 3.3+, MSVC 19.0+, or any other compiler with full C++11 support.")
-    endif()
-
-    # Let's just hope that all gccs support these options and skip the tests...
-    # -fno-strict-aliasing is needed apparently for Qt < 4.6
-    set(CMAKE_CXX_FLAGS                  "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Wextra -Wnon-virtual-dtor -fno-strict-aliasing -Wundef -Wcast-align -Wpointer-arith -Wformat-security -fno-check-new -fno-common")
-    #  set(CMAKE_CXX_FLAGS_RELEASE          "-O2")   # use CMake default
-    #  set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-g -O2")  # use CMake default
-    set(CMAKE_CXX_FLAGS_DEBUG             "-g -ggdb -O2 -fno-reorder-blocks -fno-schedule-insns -fno-inline")
-
-    check_cxx_compiler_flag(-Woverloaded-virtual CXX_W_OVERLOADED_VIRTUAL)
-    if(CXX_W_OVERLOADED_VIRTUAL)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Woverloaded-virtual")
-    endif()
-
-    # Just for miniz
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wno-unused-function -Wno-undef -fno-strict-aliasing")
-
-# ... and for Clang
-elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "3.3")
-        message(FATAL_ERROR "Your compiler is too old; you need Clang 3.3+, GCC 4.8+, MSVC 19.0+, or any other compiler with full C++11 support.")
+function(check_and_set_linker_flag flag name outvar)
+    cmake_push_check_state(RESET)
+    set(CMAKE_REQUIRED_FLAGS "${flag}")
+    check_cxx_compiler_flag("" LINKER_SUPPORTS_${name})
+    if (LINKER_SUPPORTS_${name})
+        set(${outvar} "${${outvar}} ${flag}" PARENT_SCOPE)

     endif()
     endif()

-
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wnon-virtual-dtor -Wno-long-long -Wundef -Wcast-align -Wchar-subscripts -Wall -W -Wextra -Wpointer-arith -Wformat-security -Woverloaded-virtual -fno-common -Wno-deprecated-register")
-    #  set(CMAKE_CXX_FLAGS_RELEASE        "-O2 -DNDEBUG -DQT_NO_DEBUG")     # Use CMake default
-    #  set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O2 -g -DNDEBUG -DQT_NO_DEBUG")  # Use CMake default
-    set(CMAKE_CXX_FLAGS_DEBUG          "-g -O2 -fno-inline")
-
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wno-unused-function -Wno-undef -fno-strict-aliasing")
-
-# For MSVC, at least do a version sanity check...
-elseif(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "19.0")
-        message(FATAL_ERROR "Your compiler is too old; you need at least Visual Studio 2015 (MSVC 19.0+), GCC 4.8+, Clang 3.3+, or any other compiler with full C++11 support.")
-    endif()
-
-    # ... and enable exception handling (required for STL types)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /EHsc")
-
-# Unknown/unsupported compiler
+    cmake_pop_check_state()
+endfunction()
+
+# General compile settings
+set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD_REQUIRED OFF)    # Rely on compile features if standard is not supported
+set(CMAKE_CXX_EXTENSIONS OFF)           # We like to be standard conform
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
+# For GCC and Clang, enable a whole bunch of warnings
+if (CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
+    add_compile_options(
+        -Wall
+        -Wcast-align
+        -Wextra
+        -Wformat-security
+        -Wno-unknown-pragmas
+        -Wnon-virtual-dtor
+        -Wpedantic
+        -Wundef
+        -fno-common
+        -fstack-protector-strong
+        -fvisibility=default
+        -fvisibility-inlines-hidden
+        "$<$<NOT:$<CONFIG:Debug>>:-U_FORTIFY_SOURCE;-D_FORTIFY_SOURCE=2>"
+    )
+
+    # Check for and set linker flags
+    check_and_set_linker_flag("-Wl,-z,relro"    RELRO     LINKER_FLAGS)
+    check_and_set_linker_flag("-Wl,-z,now"      NOW       LINKER_FLAGS)
+    check_and_set_linker_flag("-Wl,--as-needed" AS_NEEDED LINKER_FLAGS)
+
+    set(CMAKE_EXE_LINKER_FLAGS    "${CMAKE_EXE_LINKER_FLAGS} ${LINKER_FLAGS}")
+    set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${LINKER_FLAGS}")
+    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${LINKER_FLAGS}")

 else()
 else()

-    message(WARNING "Unknown or unsupported compiler. Make sure to enable C++11 support. Good luck.")
+    # For other compilers, we rely on default settings (unless someone provides a good set of options; patches welcome!)

 endif()
 
 # Mac build stuff
 if (APPLE AND DEPLOY)
     set(CMAKE_OSX_ARCHITECTURES "x86_64")
 endif()
 
 # Mac build stuff
 if (APPLE AND DEPLOY)
     set(CMAKE_OSX_ARCHITECTURES "x86_64")

-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mmacosx-version-min=10.9 -stdlib=libc++")
+    add_compile_options(
+        -mmacosx-version-min=10.9
+        -stdlib=libc++
+    )

 endif()
 endif()

diff --git a/cmake/QuasselMacros.cmake b/cmake/QuasselMacros.cmake
index 1c0c687..02b3165 100644 (file)
--- a/cmake/QuasselMacros.cmake
+++ b/cmake/QuasselMacros.cmake
@@ -7,6 +7,7 @@
 ###################################################################################################
 
 include(CMakeParseArguments)
 ###################################################################################################
 
 include(CMakeParseArguments)

+include(QuasselCompileFeatures)

 
 ###################################################################################################
 # Adds a library target for a Quassel module.
 
 ###################################################################################################
 # Adds a library target for a Quassel module.


@@ -41,6 +42,8 @@ function(quassel_add_module _module)
         PRIVATE ${CMAKE_CURRENT_BINARY_DIR} # for generated files
     )
 
         PRIVATE ${CMAKE_CURRENT_BINARY_DIR} # for generated files
     )
 

+    target_compile_features(${target} PUBLIC ${QUASSEL_COMPILE_FEATURES})
+

     # Export the target name for further use
     set(TARGET ${target} PARENT_SCOPE)
 endfunction()
     # Export the target name for further use
     set(TARGET ${target} PARENT_SCOPE)
 endfunction()