open65421.h: fix incompatibilities with C++20

C++20 deprecated compound volatile operations, so this code fails to
compile in C++20 mode d/t -Werror.

Fix by separating loading and saving of the value, which, in some
cases, even reduces the per-operation loads from two to one.

Fixes: QTBUG-104646
Change-Id: Ife950484bf111b92ec63f402b18b3bf4a310efc8
Reviewed-by: Frank Meerkoetter <frank.meerkoetter@basyskom.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
(cherry picked from commit 891080139d0fba52d5ace910455f28214002dbaa)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 108 insertions, 9 deletions

diff --git a/src/3rdparty/open62541/open62541.h b/src/3rdparty/open62541/open62541.h
index 7089942..5d96866 100644
--- a/src/3rdparty/open62541/open62541.h
+++ b/src/3rdparty/open62541/open62541.h
@@ -1259,8 +1259,10 @@ UA_atomic_addUInt32(volatile uint32_t *addr, uint32_t increase) {
     return __sync_add_and_fetch(addr, increase);
 #endif
 #else
-    *addr += increase;
-    return *addr;
+    uint32_t accu = *addr;
+    accu += increase;
+    *addr = accu;
+    return accu;
 #endif
 }
 
@@ -1273,8 +1275,10 @@ UA_atomic_addSize(volatile size_t *addr, size_t increase) {
     return __sync_add_and_fetch(addr, increase);
 #endif
 #else
-    *addr += increase;
-    return *addr;
+    size_t accu = *addr;
+    accu += increase;
+    *addr = accu;
+    return accu;
 #endif
 }
 
@@ -1287,8 +1291,10 @@ UA_atomic_subUInt32(volatile uint32_t *addr, uint32_t decrease) {
     return __sync_sub_and_fetch(addr, decrease);
 #endif
 #else
-    *addr -= decrease;
-    return *addr;
+    uint32_t accu = *addr;
+    accu -= decrease;
+    *addr = accu;
+    return accu;
 #endif
 }
 
@@ -1301,8 +1307,10 @@ UA_atomic_subSize(volatile size_t *addr, size_t decrease) {
     return __sync_sub_and_fetch(addr, decrease);
 #endif
 #else
-    *addr -= decrease;
-    return *addr;
+    size_t accu = *addr;
+    accu -= decrease;
+    *addr = accu;
+    return accu;
 #endif
 }
 
@@ -23415,7 +23423,7 @@ UA_constantTimeEqual(const void *ptr1, const void *ptr2, size_t length) {
     volatile UA_Byte c = 0;
     for(size_t i = 0; i < length; ++i) {
         UA_Byte x = a[i], y = b[i];
-        c |= x ^ y;
+        c = c | (x ^ y);
     }
     return !c;
 }
diff --git a/src/3rdparty/open62541/patches/0001-fix-core-use-of-compound-volatile-operations-depreca.patch b/src/3rdparty/open62541/patches/0001-fix-core-use-of-compound-volatile-operations-depreca.patch
new file mode 100644
index 0000000..ad2d07f
--- /dev/null
+++ b/src/3rdparty/open62541/patches/0001-fix-core-use-of-compound-volatile-operations-depreca.patch
@@ -0,0 +1,91 @@
+From 464966135e5cc7af30d9a3f6bdc81be937b95ac3 Mon Sep 17 00:00:00 2001
+From: Marc Mutz <marc.mutz@qt.io>
+Date: Fri, 1 Jul 2022 09:53:55 +0200
+Subject: [PATCH] fix(core): use of compound volatile operations (deprecated in
+ C++20)
+
+C++20 deprecated compound volatile operations, so this code fails to
+compile in C++20 mode due to -Werror.
+
+Fix by separating loading and saving of the value, which, in the case
+of architecture_definitions.h, even reduces the per-operation loads
+from two to one.
+
+Fixes: #5247
+---
+ include/open62541/architecture_definitions.h | 24 +++++++++++++-------
+ include/open62541/util.h                     |  2 +-
+ 2 files changed, 17 insertions(+), 9 deletions(-)
+
+diff --git a/include/open62541/architecture_definitions.h b/include/open62541/architecture_definitions.h
+index f22f401d..15a21505 100644
+--- a/include/open62541/architecture_definitions.h
++++ b/include/open62541/architecture_definitions.h
+@@ -456,8 +456,10 @@ UA_atomic_addUInt32(volatile uint32_t *addr, uint32_t increase) {
+     return __sync_add_and_fetch(addr, increase);
+ #endif
+ #else
+-    *addr += increase;
+-    return *addr;
++    uint32_t accu = *addr;
++    accu += increase;
++    *addr = accu;
++    return accu;
+ #endif
+ }
+ 
+@@ -470,8 +472,10 @@ UA_atomic_addSize(volatile size_t *addr, size_t increase) {
+     return __sync_add_and_fetch(addr, increase);
+ #endif
+ #else
+-    *addr += increase;
+-    return *addr;
++    size_t accu = *addr;
++    accu += increase;
++    *addr = accu;
++    return accu;
+ #endif
+ }
+ 
+@@ -484,8 +488,10 @@ UA_atomic_subUInt32(volatile uint32_t *addr, uint32_t decrease) {
+     return __sync_sub_and_fetch(addr, decrease);
+ #endif
+ #else
+-    *addr -= decrease;
+-    return *addr;
++    uint32_t accu = *addr;
++    accu -= decrease;
++    *addr = accu;
++    return accu;
+ #endif
+ }
+ 
+@@ -498,8 +504,10 @@ UA_atomic_subSize(volatile size_t *addr, size_t decrease) {
+     return __sync_sub_and_fetch(addr, decrease);
+ #endif
+ #else
+-    *addr -= decrease;
+-    return *addr;
++    size_t accu = *addr;
++    accu -= decrease;
++    *addr = accu;
++    return accu;
+ #endif
+ }
+ 
+diff --git a/include/open62541/util.h b/include/open62541/util.h
+index 79e49f20..9f3b5fea 100644
+--- a/include/open62541/util.h
++++ b/include/open62541/util.h
+@@ -213,7 +213,7 @@ UA_constantTimeEqual(const void *ptr1, const void *ptr2, size_t length) {
+     volatile UA_Byte c = 0;
+     for(size_t i = 0; i < length; ++i) {
+         UA_Byte x = a[i], y = b[i];
+-        c |= x ^ y;
++        c = c | (x ^ y);
+     }
+     return !c;
+ }
+-- 
+2.25.1
+