xref: /OK3568_Linux_fs/yocto/meta-qt5/recipes-qt/qt5/qtbase/0019-tst_QPluginLoader-Simplify-creating-a-fake-pointer-i.patch (revision 4882a59341e53eb6f0b4789bf948001014eff981)

From f6b67c71be078d5f58042882e801b9af6634e483 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin@martin.st>
Date: Fri, 20 Aug 2021 12:10:25 +0300
Subject: [PATCH] tst_QPluginLoader: Simplify creating a fake pointer in
 fakeplugin.cpp

When assigning multiple variables to a specific section, both GCC
and Clang legitimately error out if those variables wouldn't end
up in the same section (e.g. if one of them is going to a read-only
section while the other one is going to a read-write section).

In C++, when a seemingly const variable needs dynamic initialization,
it needs to be stored in a read-write section.

Clang 13 changed internals for how some constants are materialized.
Now, when a variable is initialized with an expression containing
plain old fashioned casts, it is considered to be potentially
runtime initialized (at the point when section assignment conflicts
is evaluated). Therefore, Clang 13 errors out on fakeplugin.cpp
with errors like:

    fakeplugin.cpp:36:39: error: 'message' causes a section type conflict with 'pluginSection'
    QT_PLUGIN_METADATA_SECTION const char message[] = "QTMETADATA";
                                          ^
    fakeplugin.cpp:32:40: note: declared here
    QT_PLUGIN_METADATA_SECTION void *const pluginSection = (void*)(0xc0ffeec0ffeeL);
                                           ^

See https://bugs.llvm.org/show_bug.cgi?id=51442 for discussion
on the matter in Clang.

To simplify things, just initialize the fake pointers as regular
uintptr_t instead, avoiding the whole matter. This produces the
exact same contents in the section as before.

For what it's worth, the actual manually constructed metadata in
fakeplugin.cpp doesn't seem to have any effect on running the
QPluginLoader tests on either ELF or MachO right now.

Upstream-Status: Backport [https://codereview.qt-project.org/c/qt/qtbase/+/366218]
Change-Id: Ib84a2ceb20cb8e3a1bb5132a5715538e08049616
Pick-to: 6.2 6.1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
 tests/auto/corelib/plugin/qpluginloader/fakeplugin.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/auto/corelib/plugin/qpluginloader/fakeplugin.cpp b/tests/auto/corelib/plugin/qpluginloader/fakeplugin.cpp
index 9e7a1f750b..a6d53f350f 100644
--- a/tests/auto/corelib/plugin/qpluginloader/fakeplugin.cpp
+++ b/tests/auto/corelib/plugin/qpluginloader/fakeplugin.cpp
@@ -29,8 +29,8 @@
 #include <QtCore/qplugin.h>

 #if QT_POINTER_SIZE == 8
-QT_PLUGIN_METADATA_SECTION void *const pluginSection = (void*)(0xc0ffeec0ffeeL);
+QT_PLUGIN_METADATA_SECTION const uintptr_t pluginSection = 0xc0ffeec0ffeeULL;
 #else
-QT_PLUGIN_METADATA_SECTION void *const pluginSection = (void*)0xc0ffee;
+QT_PLUGIN_METADATA_SECTION const uintptr_t pluginSection = 0xc0ffee;
 #endif
 QT_PLUGIN_METADATA_SECTION const char message[] = "QTMETADATA";