| Summary: | Visibility problems with Apple's Xcode/clang compilers | ||
|---|---|---|---|
| Product: | [Frameworks and Libraries] extra-cmake-modules | Reporter: | RJVB <rjvbertin> |
| Component: | general | Assignee: | ecm-bugs-null <ecm-bugs-null> |
| Status: | RESOLVED WORKSFORME | ||
| Severity: | normal | CC: | kdelibs-bugs |
| Priority: | NOR | ||
| Version: | unspecified | ||
| Target Milestone: | --- | ||
| Platform: | Compiled Sources | ||
| OS: | macOS | ||
| URL: | https://phabricator.kde.org/D16894 | ||
| Latest Commit: | Version Fixed In: | ||
| Sentry Crash Report: | |||
| Attachments: |
libkcddb 18.08.3 build log with AppleClang 602
build log with clang 5.0.2 from MacPorts AppleClang build commands for configpage.cpp, sites.cpp and the failed link command formatted for side-by-side comparison clang build commands for configpage.cpp, sites.cpp and the failed link command formatted for side-by-side comparison sites.cpp preprocessed by AppleClang sites.cpp preprocessed by clang 5.0.2 |
||
Created attachment 116293 [details]
libkcddb 18.08.3 build log with AppleClang 602
Created attachment 116294 [details]
build log with clang 5.0.2 from MacPorts
Created attachment 116295 [details]
AppleClang build commands for configpage.cpp, sites.cpp and the failed link command formatted for side-by-side comparison
Created attachment 116296 [details]
clang build commands for configpage.cpp, sites.cpp and the failed link command formatted for side-by-side comparison
Created attachment 116297 [details]
sites.cpp preprocessed by AppleClang
Created attachment 116298 [details]
sites.cpp preprocessed by clang 5.0.2
Moving this to KConfig because it looks like kconfig_compiler_kf5 fails with AppleClang, generating empty export macros:
```
> diff -u libkcddb-18.08.3/build-*clang/libkcddb/kcddb_export.h
--- libkcddb-18.08.3/build-appleclang/libkcddb/kcddb_export.h 2018-11-14 00:04:58.000000000 +0100
+++ libkcddb-18.08.3/build-clang/libkcddb/kcddb_export.h 2018-11-13 23:18:12.000000000 +0100
@@ -9,15 +9,15 @@
# ifndef KCDDB_EXPORT
# ifdef KF5Cddb_EXPORTS
/* We are building this library */
-# define KCDDB_EXPORT
+# define KCDDB_EXPORT __attribute__((visibility("default")))
# else
/* We are using this library */
-# define KCDDB_EXPORT
+# define KCDDB_EXPORT __attribute__((visibility("default")))
# endif
# endif
# ifndef KCDDB_NO_EXPORT
-# define KCDDB_NO_EXPORT
+# define KCDDB_NO_EXPORT __attribute__((visibility("hidden")))
# endif
#endif
```
Why this happens only for certain projects is a mystery to me (as is the way this command can know what compiler syntax to generate).
Apologies, my initial hunch was right, this is an ECM issue. See https://phabricator.kde.org/D16894 Thank you for reporting this issue in KDE software. As it has been a while since this issue was reported, can we please ask you to see if you can reproduce the issue with a recent software version? If you can reproduce the issue, please change the status to "REPORTED" when replying. Thank you! Dear Bug Submitter, This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information as soon as possible and set the bug status as REPORTED. Due to regular bug tracker maintenance, if the bug is still in NEEDSINFO status with no change in 30 days the bug will be closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging If you have already provided the requested information, please mark the bug as REPORTED so that the KDE team knows that the bug is ready to be confirmed. Thank you for helping us make KDE software even better for everyone! This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone! |
There appears to be something different with Apple's clang compilers from Xcode (AppleClang) which can cause problems when building with hidden symbol visibility. Link failures will arise in certain projects because symbols (from libraries built by the same project) that should be visible but are not. Sometimes the issue occurs only on newer OS versions (I can build kde4-workspace with AppleClang on OS X 10.9 but the build fails with missing symbols on 10.13 and up). An example where this started happening recently: libkcddb . This fails to link with AppleClang, not just on my ageing 10.9.5 system but also on an up-to-date 10.13 system. I'll be attaching full build logs, but here's the link error: /usr/bin/clang++ -std=c++0x -fno-operator-names -fno-exceptions -DQT_NO_EXCEPTIONS -Wno-gnu-zero-variadic-macro-arguments -Wall -Wextra -Wcast-align -Wchar-subscripts -Wformat-security -Wno-long-long -Wpointer-arith -Wundef -Wnon-virtual-dtor -Woverloaded-virtual -Werror=return-type -Wvla -pedantic -Wzero-as-null-pointer-constant -bundle -Wl,-headerpad_max_install_names -multiply_defined suppress -o kcm_cddb.so CMakeFiles/kcm_cddb.dir/cddbconfigwidget.cpp.o CMakeFiles/kcm_cddb.dir/kcmcddb.cpp.o CMakeFiles/kcm_cddb.dir/kcm_cddb_autogen/mocs_compilation.cpp.o /opt/local/lib/libKF5KIOWidgets.5.47.0.dylib ../libkcddb/libKF5Cddb.5.0.0.dylib /opt/local/lib/libKF5ConfigWidgets.5.47.0.dylib /opt/local/lib/libKF5JobWidgets.5.47.0.dylib /opt/local/lib/libKF5Completion.5.47.0.dylib /opt/local/lib/libKF5WidgetsAddons.5.47.0.dylib /opt/local/lib/libKF5KIOCore.5.47.0.dylib /opt/local/lib/libKF5Auth.5.47.0.dylib /opt/local/libexec/qt5/Library/Frameworks/QtWidgets.framework/QtWidgets /opt/local/lib/libKF5Service.5.47.0.dylib /opt/local/lib/libKF5I18n.5.47.0.dylib /opt/local/lib/libKF5CoreAddons.5.47.0.dylib /opt/local/libexec/qt5/Library/Frameworks/QtConcurrent.framework/QtConcurrent /opt/local/libexec/qt5/Library/Frameworks/QtDBus.framework/QtDBus /opt/local/lib/libKF5Codecs.5.47.0.dylib /opt/local/lib/libKF5ConfigGui.5.47.0.dylib /opt/local/libexec/qt5/Library/Frameworks/QtGui.framework/QtGui /opt/local/libexec/qt5/Library/Frameworks/QtXml.framework/QtXml /opt/local/lib/libKF5ConfigCore.5.47.0.dylib /opt/local/libexec/qt5/Library/Frameworks/QtNetwork.framework/QtNetwork /opt/local/libexec/qt5/Library/Frameworks/QtCore.framework/QtCore Undefined symbols for architecture x86_64: "ConfigBase::setFreedbSubmitTransport(int)", referenced from: CDDBModule::checkSettings() const in kcmcddb.cpp.o "ConfigBase::~ConfigBase()", referenced from: KCDDB::Config::~Config() in kcmcddb.cpp.o "KCDDB::Sites::siteList()", referenced from: CDDBConfigWidget::showMirrorList() in cddbconfigwidget.cpp.o "KCDDB::Sites::Sites()", referenced from: CDDBConfigWidget::showMirrorList() in cddbconfigwidget.cpp.o "KCDDB::Config::Config()", referenced from: CDDBModule::CDDBModule(QWidget*, QList<QVariant> const&) in kcmcddb.cpp.o CDDBModule::defaults() in kcmcddb.cpp.o CDDBModule::checkSettings() const in kcmcddb.cpp.o CDDBModule::load() in kcmcddb.cpp.o "ConfigBase::emailAddress() const", referenced from: CDDBModule::checkSettings() const in kcmcddb.cpp.o "ConfigBase::smtpHostname() const", referenced from: CDDBModule::checkSettings() const in kcmcddb.cpp.o "ConfigBase::smtpUsername() const", referenced from: CDDBModule::updateWidgetsFromConfig(KCDDB::Config const&) in kcmcddb.cpp.o "ConfigBase::freedbSubmitTransport() const", referenced from: CDDBModule::checkSettings() const in kcmcddb.cpp.o "ConfigBase::replyTo() const", referenced from: CDDBModule::checkSettings() const in kcmcddb.cpp.o ld: symbol(s) not found for architecture x86_64 This error goes away when using a stock clang compiler, for instance clang-4.0 or clang-5.0 from MacPorts. The symbols in question are defined in sites.cpp and in the autogenerated configbase.cpp (auto-generated files are identical for the different compilers I tested). Looking at the build logs there are no differences in the compiler arguments between the various builds, other than in the build directory path. Yet the Sites::siteList() symbol is visible in the build by stock clang (5.0.2) and not in the one by AppleClang: 000000000001bdc0 T __ZN5KCDDB5Sites8siteListEv vs. 000000000001bc80 t __ZN5KCDDB5Sites8siteListEv I have only seen this with KDE code for now, never elsewhere.