C++ std::stable_sort crashes on iOS 12

Developer Tools & Services Xcode
kkq OP
Created Nov ’23
Replies 9
Boosts 0
Views 1.1k
Participants 4

Xcode 15 creates a binary that causes a crash on iOS 12 when I use C++ std::stable_sort. The following code works on iOS 17 but causes a crash on iOS 12. I remember that the earlier Xcode had no problem. It is no problem when I change "std::stable_sort" to "std::sort".

FB13430187

//
//  Tests.cpp
//

#include <tuple>
#include <vector>
#include <algorithm>
#include <iostream>

extern "C" {

void execute_tests(void)
{
    using T = std::tuple<size_t, uint64_t *>;
    std::vector<T> vector = { {7, nullptr}, {4, nullptr}, {9, nullptr} };
    std::stable_sort(vector.begin(), vector.end(), [](const T& a, const T& b){
        return std::get<0>(a) < std::get<0>(b);
    });
    for (const T& item : vector) {
        std::cout << std::get<0>(item) << std::endl;
    }
}

}
Answered by galad87 in 773517022

Try to switch back to the old linker. Xcode 15 ships with a new linker that might cause issues on older iOS versions (it definitely has issues on older macOS versions).

Replies  9
Boosts  0
Views  1.1k
Participants  4
endecotp OP
Dec ’23

How exactly does it crash?

0
kkq OP
Dec ’23

Xcode Version 15.0.1 (15A507), iPad mini 3, iOS 12.5.7 (16H81)

It crashes at an inline function.

template <class _Tp>
_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI _LIBCPP_DEPRECATED_IN_CXX17
pair<_Tp*, ptrdiff_t>
get_temporary_buffer(ptrdiff_t __n) _NOEXCEPT

crash at iPhoneOS17.0.sdk/usr/include/c++/v1/__memory/temprary_buffer.h:46

            __r.first = static_cast<_Tp*>(::operator new(
                __n * sizeof(_Tp), nothrow));

call back trace:

Thread 1 Queue : com.apple.main-thread (serial)
#0	0x0000000000000000 in 0x00000000 ()
#1	0x000000010096df10 in std::__1::pair<std::__1::tuple<unsigned long, unsigned long long*>*, long> std::__1::get_temporary_buffer[abi:v160006]<std::__1::tuple<unsigned long, unsigned long long*>>(long) at /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS17.0.sdk/usr/include/c++/v1/__memory/temporary_buffer.h:46
#2	0x000000010096dd58 in void std::__1::__stable_sort_impl[abi:v160006]<std::__1::_ClassicAlgPolicy, std::__1::__wrap_iter<std::__1::tuple<unsigned long, unsigned long long*>*>, execute_tests::$_0>(std::__1::__wrap_iter<std::__1::tuple<unsigned long, unsigned long long*>*>, std::__1::__wrap_iter<std::__1::tuple<unsigned long, unsigned long long*>*>, execute_tests::$_0&) at /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS17.0.sdk/usr/include/c++/v1/__algorithm/stable_sort.h:225
#3	0x000000010096c2a4 in void std::__1::stable_sort[abi:v160006]<std::__1::__wrap_iter<std::__1::tuple<unsigned long, unsigned long long*>*>, execute_tests::$_0>(std::__1::__wrap_iter<std::__1::tuple<unsigned long, unsigned long long*>*>, std::__1::__wrap_iter<std::__1::tuple<unsigned long, unsigned long long*>*>, execute_tests::$_0) at /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS17.0.sdk/usr/include/c++/v1/__algorithm/stable_sort.h:236
#4	0x000000010096c110 in ::execute_tests() at /System/Volumes/Data/Developer/codes/test5/test5/Tests.cpp:19
#5	0x0000000100971b00 in -[AppDelegate application:didFinishLaunchingWithOptions:] at /System/Volumes/Data/Developer/codes/test5/test5/AppDelegate.m:21
#6	0x0000000256eca0f0 in -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] ()
#7	0x0000000256ecb854 in -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] ()
#8	0x0000000256ed0fe0 in -[UIApplication _runWithMainScene:transitionContext:completion:] ()
#9	0x00000002567942a4 in __111-[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:]_block_invoke ()
#10	0x000000025679c83c in +[_UICanvas _enqueuePostSettingUpdateTransactionBlock:] ()
#11	0x0000000256793f28 in -[__UICanvasLifecycleMonitor_Compatability _scheduleFirstCommitForScene:transition:firstActivation:completion:] ()
#12	0x0000000256794818 in -[__UICanvasLifecycleMonitor_Compatability activateEventsOnly:withContext:completion:] ()
#13	0x0000000256792b64 in __82-[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:]_block_invoke ()
#14	0x000000025679282c in -[_UIApplicationCanvas _transitionLifecycleStateWithTransitionContext:completion:] ()
#15	0x000000025679736c in __125-[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:]_block_invoke ()
#16	0x0000000256798150 in _performActionsWithDelayForTransitionContext ()
#17	0x0000000256797224 in -[_UICanvasLifecycleSettingsDiffAction performActionsForCanvas:withUpdatedScene:settingsDiff:fromSettings:transitionContext:] ()
#18	0x000000025679bf24 in -[_UICanvas scene:didUpdateWithDiff:transitionContext:completion:] ()
#19	0x0000000256ecf5e8 in -[UIApplication workspace:didCreateScene:withTransitionContext:completion:] ()
#20	0x0000000256acbe04 in -[UIApplicationSceneClientAgent scene:didInitializeWithEvent:completion:] ()
#21	0x000000022d1d39fc in -[FBSSceneImpl _didCreateWithTransitionContext:completion:] ()
#22	0x000000022d1dd40c in __56-[FBSWorkspace client:handleCreateScene:withCompletion:]_block_invoke_2 ()
#23	0x000000022d1dcc14 in __40-[FBSWorkspace _performDelegateCallOut:]_block_invoke ()
#24	0x0000000100cf0c78 in _dispatch_client_callout ()
#25	0x0000000100cf4840 in _dispatch_block_invoke_direct ()
#26	0x000000022d20e040 in __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ ()
#27	0x000000022d20dcdc in -[FBSSerialQueue _performNext] ()
#28	0x000000022d20e294 in -[FBSSerialQueue _performNextFromRunLoopSource] ()
#29	0x000000022a7e7f1c in __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ ()
#30	0x000000022a7e7e9c in __CFRunLoopDoSource0 ()
#31	0x000000022a7e7784 in __CFRunLoopDoSources0 ()
#32	0x000000022a7e26c0 in __CFRunLoopRun ()
#33	0x000000022a7e1fb4 in CFRunLoopRunSpecific ()
#34	0x000000022c9e479c in GSEventRunModal ()
#35	0x0000000256ed2c38 in UIApplicationMain ()
#36	0x0000000100971ba8 in main at /System/Volumes/Data/Developer/codes/test5/test5/main.m:17
0
kkq OP
Dec ’23

Error is that:

Thread 1: EXC_BAD_ACCESS (code=1, address=0x0)

0
galad87 OP
Dec ’23
Accepted Answer

Try to switch back to the old linker. Xcode 15 ships with a new linker that might cause issues on older iOS versions (it definitely has issues on older macOS versions).

0
kkq OP
Dec ’23

@galad87 Thank you.

I added "-ld_classic" to other linker flags and the app doesn't crash on iOS 12.

0
endecotp OP
Dec ’23

Do we know if this is something that can be fixed in an iOS 12.x+1 release, or in an XCode 15.x+1 release?

0
kkq OP
Dec ’23

I hope Xcode will be fixed. The ld_prime has the problem.

0
thomasokken OP
Dec ’23

I've seen crashes, in the last week or so, with "new (std::nothrow) ClassName", with code built using Xcode 15.0.1, on iOS 12 and on an older version of MacOS (10.13, I think). The same binaries run fine on the latest iOS and MacOS. Removing the "(std::nothrow)" fixed the crash. The same code worked fine on all supported versions of MacOS and iOS when built with older Xcode.

0
endecotp OP
Dec ’23

Do we know if this is something that can be fixed in an iOS 12.x+1 release, or in an XCode 15.x+1 release?

It seems that binaries created with Xcode 15.1 work OK on iOS 12 without the need to specify -ld_classic.

I don't know if this is because the underlying problem has actually been fixed, or whether it now just uses ld_classic by default when the target is iOS 12.

0
C++ std::stable_sort crashes on iOS 12
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