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@@ -1,117 +0,0 @@
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-From 71830c804be76cf6abe913ac2fe584947b7a91ea Mon Sep 17 00:00:00 2001
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-From: Samuel Martin <s.martin49@gmail.com>
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-Date: Tue, 24 May 2016 23:08:40 +0200
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-Subject: [PATCH] cmake: add check for explicit linking against libatomic
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-
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-To use atomics functions, some toolchains requires to explicitly add
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--latomic to the linker flags (because they are not provided by libc,
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-but libatomic).
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-
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-This change adds a helper function trying to build/link a test program
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-using atomics, then calls it to:
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-* first check if atomics are directly available in the libc;
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-* if not and libatomic has been found, then run the same test with
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- "-latomic" added to the linker flags.
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-The pulseview link library list is updated according to the results of
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-these tests.
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-
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-This issue was triggered by the Buildroot farms:
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- http://autobuild.buildroot.org/results/1e3/1e3101261252d5f30fdf842cc99604e4f4c25eef/build-end.log
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-
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-Notes:
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-1- CMAKE_REQUIRED_* variables are only used in check functions. They
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- are not automatically forwarded to/handled by the target commands
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- (such as target_link_library), because the check functions are
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- implemented as macro in CMake code, whereas many target commands
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- are native.
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-2- Because of note #1, CMAKE_REQUIRED_LIBRARIES (or its value) must be
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- explicitly passed to the target_link_library command when this is
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- needed.
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-3- In this implementation, LIBATOMIC_LIBRARY is only set when it is
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- needed; so, unconditionally appending it to PULSEVIEW_LINK_LIBS
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- will produce the expected behavior.
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-
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-Signed-off-by: Samuel Martin <s.martin49@gmail.com>
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-
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----
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-changes v1->v2:
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-- use std::atomic_fetch_add_explicit function instead of
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- __atomic_fetch_add_4;
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-- rework code using cmake_*_check_state and find_library helpers;
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-- quiet-ize checks and clean outputs
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-- extend the commit log
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----
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- CMakeLists.txt | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
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- 1 file changed, 50 insertions(+)
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-
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-diff --git a/CMakeLists.txt b/CMakeLists.txt
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-index 9dac69f..44f810e 100644
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---- a/CMakeLists.txt
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-+++ b/CMakeLists.txt
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-@@ -107,6 +107,55 @@ endif()
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- # This will set ${CMAKE_THREAD_LIBS_INIT} to the correct, OS-specific value.
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- find_package(Threads REQUIRED)
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-
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-+
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-+# Check for explicit link against libatomic
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-+#
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-+# Depending on the toolchain, linking a program using atomic functions may need
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-+# "-latomic" explicitly passed to the linker
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-+#
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-+# This check first tests if atomics are available in the C-library, if not and
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-+# libatomic exists, then it runs the same test with -latomic added to the
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-+# linker flags.
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-+
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-+# Helper for checking for atomics
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-+function(check_working_cxx_atomics varname additional_lib)
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-+ include(CheckCXXSourceCompiles)
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-+ include(CMakePushCheckState)
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-+ cmake_push_check_state()
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-+ set(CMAKE_REQUIRED_FLAGS "-std=c++11")
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-+ set(CMAKE_REQUIRED_LIBRARIES "${additional_lib}")
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-+ set(CMAKE_REQUIRED_QUIET 1)
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-+ CHECK_CXX_SOURCE_COMPILES("
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-+#include <atomic>
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-+std::atomic<int> x;
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-+int main() {
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-+ return std::atomic_fetch_add_explicit(&x, 1, std::memory_order_seq_cst);
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-+}
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-+" ${varname})
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-+ cmake_pop_check_state()
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-+endfunction(check_working_cxx_atomics)
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-+
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-+# First check if atomics work without the library.
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-+# If not, check if the library exists, and atomics work with it.
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-+check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITHOUT_LIB "")
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-+if(HAVE_CXX_ATOMICS_WITHOUT_LIB)
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-+ message(STATUS "Atomics provided by the C-library - yes")
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-+else()
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-+ message(STATUS "Atomics provided by the C-library - no")
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-+ find_library(LIBATOMIC_LIBRARY NAMES atomic PATH_SUFFIXES lib)
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-+ if(LIBATOMIC_LIBRARY)
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-+ check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITH_LIB "${LIBATOMIC_LIBRARY}")
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-+ if (HAVE_CXX_ATOMICS_WITH_LIB)
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-+ message(STATUS "Atomics provided by libatomic - yes")
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-+ else()
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-+ message(STATUS "Atomics provided by libatomic - no")
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-+ message(FATAL_ERROR "Compiler must support std::atomic!")
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-+ endif()
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-+ else()
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-+ message(FATAL_ERROR "Compiler appears to require libatomic, but cannot find it.")
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-+ endif()
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-+endif()
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-+
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- #===============================================================================
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- #= System Introspection
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- #-------------------------------------------------------------------------------
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-@@ -387,6 +436,7 @@ set(PULSEVIEW_LINK_LIBS
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- ${Boost_LIBRARIES}
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- ${QT_LIBRARIES}
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- ${CMAKE_THREAD_LIBS_INIT}
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-+ ${LIBATOMIC_LIBRARY}
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- )
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-
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- if(STATIC_PKGDEPS_LIBS)
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---
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-2.8.3
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-
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Bartosz Golaszewski