Backport two upstream patches to fix libatomic detection.

debian/changelog

@@ -1,5 +1,7 @@
 qt6-base (6.2.4+dfsg-7) UNRELEASED; urgency=medium
 
+  [ Dmitry Shachnev ]
+  * Backport two upstream patches to fix libatomic detection.
 
  -- Debian Qt/KDE Maintainers <debian-qt-kde@lists.debian.org>  Sat, 14 May 2022 17:41:32 +0300
 

debian/patches/series

@@ -1,6 +1,10 @@
 # fixed in 6.3
 upstream_QStorageInfo-limit-Linux-only-code-with-Q_OS_LINUX.patch
 
+# fixed in 6.3.1
+upstream_Explicitly-check-for-atomic-addition.patch
+upstream_Hardcode-atomic_LIB-as-latomic.patch
+
 # fixed in 6.4
 upstream_CMake-add-support-for-GNU-Hurd.patch
 upstream_QProcess-Unix-fallback-on-_POSIX_PIPE_BUF-w-missing-.patch

debian/patches/upstream_Explicitly-check-for-atomic-addition.patch

@@ -0,0 +1,82 @@
+From 4088b27b9397fa9877bf60b8e707bba5dc51e9cb Mon Sep 17 00:00:00 2001
+From: Moody Liu <mooodyhunter@outlook.com>
+Date: Tue, 12 Apr 2022 10:40:00 +0100
+Subject: [PATCH] Explicitly check for atomic addition and relaxed load
+ operation support
+
+...and properly find and link against `libatomic` using find_library.
+This fixes the qtdeclarative build on the RISC-V platform.
+
+Initial-patch-by: Sprite <SpriteOvO@gmail.com>
+Pick-to: 6.2
+Pick-to: 6.3
+Task-number: QTBUG-99234
+Change-Id: I2b5e4812886ce45cb02bed3106ce8c519b294cbe
+Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
+Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>
+---
+ cmake/FindWrapAtomic.cmake | 34 +++++++++++++++++++---------------
+ 1 file changed, 19 insertions(+), 15 deletions(-)
+
+diff --git a/cmake/FindWrapAtomic.cmake b/cmake/FindWrapAtomic.cmake
+index c2582bdd6b..3ea72bb188 100644
+--- a/cmake/FindWrapAtomic.cmake
++++ b/cmake/FindWrapAtomic.cmake
+@@ -10,35 +10,39 @@ include(CheckCXXSourceCompiles)
+ set (atomic_test_sources "#include <atomic>
+ #include <cstdint>
+ 
+-void test(volatile std::atomic<std::int64_t> &a)
+-{
+-    std::int64_t v = a.load(std::memory_order_acquire);
+-    while (!a.compare_exchange_strong(v, v + 1,
+-                                      std::memory_order_acq_rel,
+-                                      std::memory_order_acquire)) {
+-        v = a.exchange(v - 1);
+-    }
+-    a.store(v + 1, std::memory_order_release);
+-}
+-
+ int main(int, char **)
+ {
+-    void *ptr = (void*)0xffffffc0; // any random pointer
+-    test(*reinterpret_cast<std::atomic<std::int64_t> *>(ptr));
++    volatile std::atomic<char>    size_1;
++    volatile std::atomic<short>   size_2;
++    volatile std::atomic<int>     size_4;
++    volatile std::atomic<int64_t> size_8;
++
++    ++size_1;
++    ++size_2;
++    ++size_4;
++    ++size_8;
++
++    (void)size_1.load(std::memory_order_relaxed);
++    (void)size_2.load(std::memory_order_relaxed);
++    (void)size_4.load(std::memory_order_relaxed);
++    (void)size_8.load(std::memory_order_relaxed);
++
+     return 0;
+ }")
+ 
+ check_cxx_source_compiles("${atomic_test_sources}" HAVE_STDATOMIC)
+ if(NOT HAVE_STDATOMIC)
+     set(_req_libraries "${CMAKE_REQUIRED_LIBRARIES}")
+-    set(CMAKE_REQUIRED_LIBRARIES "atomic")
++    find_library(atomic_LIB atomic REQUIRED)
++    set(CMAKE_REQUIRED_LIBRARIES ${atomic_LIB})
+     check_cxx_source_compiles("${atomic_test_sources}" HAVE_STDATOMIC_WITH_LIB)
+     set(CMAKE_REQUIRED_LIBRARIES "${_req_libraries}")
+ endif()
+ 
+ add_library(WrapAtomic::WrapAtomic INTERFACE IMPORTED)
+ if(HAVE_STDATOMIC_WITH_LIB)
+-    target_link_libraries(WrapAtomic::WrapAtomic INTERFACE atomic)
++    # atomic_LIB is already found above.
++    target_link_libraries(WrapAtomic::WrapAtomic INTERFACE ${atomic_LIB})
+ endif()
+ 
+ set(WrapAtomic_FOUND 1)
+-- 
+2.35.1
+

debian/patches/upstream_Hardcode-atomic_LIB-as-latomic.patch

@@ -0,0 +1,35 @@
+From e2a8b0adbd099cfda84e931f6a24f34e80b12fd7 Mon Sep 17 00:00:00 2001
+From: Dmitry Shachnev <mitya57@gmail.com>
+Date: Sat, 7 May 2022 20:51:25 +0300
+Subject: [PATCH] Hardcode atomic_LIB as -latomic
+
+find_library does not always work because libatomic.so may be in a path
+like /usr/lib/gcc/x86_64-linux-gnu/11/libatomic.so, which CMake does not
+consider by default.
+
+Pick-to: 6.3
+Change-Id: I73a657c470efa4f84f8629bd531edfcac3b3a352
+Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
+Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
+Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
+Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>
+---
+ cmake/FindWrapAtomic.cmake | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/cmake/FindWrapAtomic.cmake b/cmake/FindWrapAtomic.cmake
+index 3ea72bb188..006be0ed8f 100644
+--- a/cmake/FindWrapAtomic.cmake
++++ b/cmake/FindWrapAtomic.cmake
+@@ -33,7 +33,7 @@ int main(int, char **)
+ check_cxx_source_compiles("${atomic_test_sources}" HAVE_STDATOMIC)
+ if(NOT HAVE_STDATOMIC)
+     set(_req_libraries "${CMAKE_REQUIRED_LIBRARIES}")
+-    find_library(atomic_LIB atomic REQUIRED)
++    set(atomic_LIB "-latomic")
+     set(CMAKE_REQUIRED_LIBRARIES ${atomic_LIB})
+     check_cxx_source_compiles("${atomic_test_sources}" HAVE_STDATOMIC_WITH_LIB)
+     set(CMAKE_REQUIRED_LIBRARIES "${_req_libraries}")
+-- 
+2.35.1
+