Hybrid AOT doesn't work on arm64 device if built with only armv7 architecture selected

[Belorus]

Steps to Reproduce

1. Create and Empty application
2. Add <AndroidAotMode>Hybrid</AndroidAotMode> to .csproj
3. Add <AotAssemblies>true</AotAssemblies> to .csproj

Repro

Expected Behavior

It works

Actual Behavior

It crashes

Version Information

Microsoft Visual Studio Professional 2017
Version 15.5.2
VisualStudio.15.Release/15.5.2+27130.2010
Microsoft .NET Framework
Version 4.7.02046

Installed Version: Professional

Xamarin 4.8.0.753 (6575bd113)
Xamarin.Android SDK 8.1.0.25 (HEAD/d8c6e504f)

Log File

hybridAOT.log

Other

In logs there are warnings like
W linker : /data/app/App1.App1-1/lib/arm/libaot-mscorlib.dll.so: is missing DT_SONAME will use basename as a replacement: "libaot-mscorlib.dll.so"

F libc : Fatal signal 11 (SIGSEGV), code 1, fault addr 0x25f44a4c in tid 12103 (App1.App1)

01-22 20:27:13.783 12150 12150 F DEBUG   : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
01-22 20:27:13.784 12150 12150 F DEBUG   : Build fingerprint: 'samsung/heroltexx/herolte:7.0/NRD90M/G930FXXS1DQLC:user/release-keys'
01-22 20:27:13.784 12150 12150 F DEBUG   : Revision: '8'
01-22 20:27:13.785 12150 12150 F DEBUG   : ABI: 'arm'
01-22 20:27:13.785 12150 12150 F DEBUG   : pid: 12103, tid: 12103, name: App1.App1  >>> App1.App1 <<<
01-22 20:27:13.785 12150 12150 F DEBUG   : signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x25f44a4c
01-22 20:27:13.785 12150 12150 F DEBUG   :     r0 00000000  r1 ffe674f4  r2 25f44a74  r3 d9f225f0
01-22 20:27:13.786 12150 12150 F DEBUG   :     r4 00000000  r5 e43f7f28  r6 ffe67908  r7 ffe674ec
01-22 20:27:13.786 12150 12150 F DEBUG   :     r8 d9f225f0  r9 d5a54690  sl ffe67a10  fp ffe67508
01-22 20:27:13.786 12150 12150 F DEBUG   :     ip ffe67494  sp 25f44a5c  lr d9f229c8  pc c64000c0  cpsr 600e0010
01-22 20:27:13.788 12150 12150 F DEBUG   : 
01-22 20:27:13.788 12150 12150 F DEBUG   : backtrace:
01-22 20:27:13.788 12150 12150 F DEBUG   :     #00 pc 001200c0  /data/app/App1.App1-1/lib/arm/libmonosgen-2.0.so

[Belorus]

Running on Samsung S7 with ARMv8 Exynos 8890 Octa
My assumption was that ARMv8 devices support ARMv7 code (in a same way as x86_64 does that with x86 instructions).

If i select armv8 or both armv7+armv8- everything works.

[bulente]

@Belorus how are you building your project with Hybrid Aot? Mine was giving method not found error while stripping system.core.dll. Doesn't your project include system.core.dll?

[Belorus]

@bulente Nope. It compiles (use steps from first message), but crashes on start (while loading first library).
If i choose armv8 architecture - it works on armv8 device.

[jonpryor]

@Belorus: what is "armv8"? arm64-v8a?

What's doubly odd is that it's consistency loading the 32-bit arm images, so it's not like it's a mixed 32-bit/64-bit problem:

70e27000-712a5000 r--p 00000000 fd:00 1249                               /system/framework/arm/boot-core-libart.oat
...
c4cff000-c4ff5000 r-xp 00000000 fd:01 197282                             /data/app/App1.App1-1/lib/arm/libaot-mscorlib.dll.so

[Belorus]

@jonpryor Binary compiled against armv7a ABI with AArch32 instructions crashes on device with armv8a CPU that natively supports both AArch64 and AArch32. And when compiled against either just arm64v8a or both armv7a & arm64-v8a it works properly on device with armv8a CPU.

[grendello]

It doesn't help much, alas, but it appears to be a problem with corrupt stack:

01-22 20:27:13.598 12103 12103 F libc : Fatal signal 11 (SIGSEGV), code 1, fault addr 0x25f44a4c in tid 12103 (App1.App1)

note the fault address

01-22 20:27:13.785 12150 12150 F DEBUG   : pid: 12103, tid: 12103, name: App1.App1  >>> App1.App1 <<<
01-22 20:27:13.785 12150 12150 F DEBUG   : signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x25f44a4c
01-22 20:27:13.785 12150 12150 F DEBUG   :     r0 00000000  r1 ffe674f4  r2 25f44a74  r3 d9f225f0
01-22 20:27:13.786 12150 12150 F DEBUG   :     r4 00000000  r5 e43f7f28  r6 ffe67908  r7 ffe674ec
01-22 20:27:13.786 12150 12150 F DEBUG   :     r8 d9f225f0  r9 d5a54690  sl ffe67a10  fp ffe67508
01-22 20:27:13.786 12150 12150 F DEBUG   :     ip ffe67494  sp 25f44a5c  lr d9f229c8  pc c64000c0  cpsr 600e0010

And note the value of the sp register here (stack pointer). The fault location is 16 bytes before the stack top, maybe a corrupt return address from a function?

[pjcollins]

I'm able to reproduce this using a d15-8 preview build (XA 8.4.0.6). I see a similar crash on both 32bit and 64bit devices if I select armeabi-v7a as my only supported architecture (release mode default).

https://gist.github.com/pjcollins/8a9c63ab2e66e6cd6567fbe234dcebc7

[tobiasschulz]

Any news?

[ysmoradi]

I reproduced this with latest version of mono (5.18) and xamarin android 9.1 preview (d16.0)
@bulente I wasn't able to build my project using hybrid aot on Windows, but it gets compiled on mac os. As like as other notes in this issue, it crashes on start up. Normal aot is working fine, with or without llvm, but hybrid aot is the one I'm looking for, please fix it. Thanks )-:

This is what I'm getting:

mono-rt 9d9a5000-9d9a6000 r-xp 00000000 b3:0d 24178 /data/app/com.companyname.XamApp-1/lib/arm/libaot-Xamarin.Forms.Platform.dll.so

libc Fatal signal 11 (SIGSEGV), code 2, fault addr 0xa1758c04 in tid 21186 (panyname.XamApp)