Bug 42664 - Could not AOT the assembly (on .EXE file)
Summary: Could not AOT the assembly (on .EXE file)
Alias: None
Product: iOS
Classification: Xamarin
Component: Mono runtime / AOT compiler ()
Version: XI 9.6 (iOS 9.3)
Hardware: All All
: --- normal
Target Milestone: Untriaged
Assignee: Zoltan Varga
Depends on:
Reported: 2016-07-19 15:45 UTC by rocco.dato
Modified: 2016-07-20 09:29 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

Build output with AOT error on EliotAppStopNGoiOS.exe (688.63 KB, application/x-7z-compressed)
2016-07-19 15:45 UTC, rocco.dato

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Description rocco.dato 2016-07-19 15:45:13 UTC
Created attachment 16719 [details]
Build output with AOT error on EliotAppStopNGoiOS.exe

Dear support,
I'm developing a commercial cross-platform app (android and iOS) but I'm facing an error when trying to build the iOS solution (with mtouch option set to "link SDK only")
The build process fails with:

Could not AOT the assembly '/Users/EmanueleDiEmanuele/Library/Caches/Xamarin/mtbs/builds/EliotAppStopNGoiOS/5901df1dbb00e5e420b8af380d31cee4/obj/iPhone/Release/mtouch-cache/64/Build/EliotAppStopNGoiOS.exe'

I can't attach the source code because of its commercial purpose, but I built the solution with MTOUCH arguments "-v -v -v -v" and stored part of the full output (the first part is missing, but there is something interesting at line 874083). This output is generated building on a MacPro from Visual Studio (via Mac Agent), but the problem appears also if I directly work on the Mac Pro machine.

How can I solve this problem? These are my system information:

=== Xamarin Studio Business ===
Version 6.0.2 (build 41)
	Mono 4.4.1 (mono-4.4.0-branch-c7sr0/4747417) (64-bit)
	GTK+ 2.24.23 (Raleigh theme)
	Package version: 404010000
=== Apple Developer Tools ===
Xcode 7.3.1 (10188.1)
Build 7D1014
=== Xamarin.Mac ===
Version: (Xamarin Business)
=== Xamarin.iOS ===
Version: (Xamarin Business)
=== Build Information ===
Mac OS X 10.11.5

Thank you
Comment 1 Zoltan Varga 2016-07-19 19:08:37 UTC
The error seems to be this:

23>  AOT Compilation exited with code 134, command: (ID attività:761)
23>  MONO_PATH=/Users/EmanueleDiEmanuele/Library/Caches/Xamarin/mtbs/builds/EliotAppStopNGoiOS/5901df1dbb00e5e420b8af380d31cee4/obj/iPhone/Release/mtouch-cache/64/Build /Library/Frameworks/Xamarin.iOS.framework/Versions/ --debug --llvm -O=gsharedvt  --aot=mtriple=arm64-ios,data-outfile=/Users/EmanueleDiEmanuele/Library/Caches/Xamarin/mtbs/builds/EliotAppStopNGoiOS/5901df1dbb00e5e420b8af380d31cee4/obj/iPhone/Release/mtouch-cache/EliotAppStopNGoiOS.arm64.aotdata,static,asmonly,direct-icalls,full,nodebug,dwarfdebug,llvm-path=/Library/Frameworks/Xamarin.iOS.framework/Versions/,outfile=/Users/EmanueleDiEmanuele/Library/Caches/Xamarin/mtbs/builds/EliotAppStopNGoiOS/5901df1dbb00e5e420b8af380d31cee4/obj/iPhone/Release/mtouch-cache/EliotAppStopNGoiOS.exe.arm64.s,llvm-outfile=/Users/EmanueleDiEmanuele/Library/Caches/Xamarin/mtbs/builds/EliotAppStopNGoiOS/5901df1dbb00e5e420b8af380d31cee4/obj/iPhone/Release/mtouch-cache/EliotAppStopNGoiOS.exe.arm64-llvm.o "/Users/EmanueleDiEmanuele/Library/Caches/Xamarin/mtbs/builds/EliotAppStopNGoiOS/5901df1dbb00e5e420b8af380d31cee4/obj/iPhone/Release/mtouch-cache/64/Build/EliotAppStopNGoiOS.exe" (ID attività:761)
23>  Mono Ahead of Time compiler - compiling assembly /Users/EmanueleDiEmanuele/Library/Caches/Xamarin/mtbs/builds/EliotAppStopNGoiOS/5901df1dbb00e5e420b8af380d31cee4/obj/iPhone/Release/mtouch-cache/64/Build/EliotAppStopNGoiOS.exe (ID attività:761)
23>  * Assertion at ../../../../../mono/mono/metadata/metadata.c:3643, condition `ptr' not met (ID attività:761)
Comment 2 Zoltan Varga 2016-07-19 19:10:36 UTC
Are there any obfuscators etc. ran on the EliotAppStopNGoiOS.exe assembly ?
Comment 3 rocco.dato 2016-07-20 09:29:01 UTC
We don't know exactly what the reason was, but we solved the problem by removing the following code which was actually unused in our app:

[DllImport (MonoTouch.Constants.SystemLibrary)]
    static internal extern int sysctl ([MarshalAs (UnmanagedType.LPArray)] int[] mib, int mibsize, IntPtr output, IntPtr oldLen, IntPtr newp, uint newlen);

    public static Dictionary<String,String> AllMac = null;
    public static String GetMACAddressByIp(String ip)
        return GetMACAddressByIp (ip, false);
    public static String GetMACAddressByIp (String ip, bool reset)
            if (AllMac == null || reset) 
                AllMac=new Dictionary<string, string>();
                int CTL_NET = 4;
                int PF_ROUTE = 17;
                int AF_INET = 2;
                int NET_RT_FLAGS = 2;
                int RTF_LLINFO = 0x400;
                int[] mib = { CTL_NET, PF_ROUTE, 0, AF_INET, NET_RT_FLAGS, RTF_LLINFO };
                var pLen = Marshal.AllocHGlobal (sizeof(int));
                sysctl (mib, 6, IntPtr.Zero, pLen, IntPtr.Zero, 0);
                var length = Marshal.ReadInt32 (pLen);
                if (length == 0) {
                    Marshal.FreeHGlobal (pLen);
                    return string.Empty;
                var pBuf = Marshal.AllocHGlobal (length);
                sysctl (mib, 6, pBuf, pLen, IntPtr.Zero, 0);
                int off = 0;
                while (true) {
                    short len = Marshal.ReadInt16 (pBuf + off);
                    IntPtr paddr = pBuf + off + 36 + 56;
                    byte sinlen = Marshal.ReadByte (paddr);  
                    uint addr = (uint)Marshal.ReadInt32 (paddr + 4);
                    string ipAddress = new IPAddress (BitConverter.GetBytes (addr)).ToString ();
                    paddr += sinlen; 
                    StringBuilder sb = new StringBuilder ();
                    bool allZero = true;
                    for (int m = 0; m < 6; m++) {
                        byte b = Marshal.ReadByte (paddr + 8 + m);
                        if (b != 0) {
                            allZero = false;
                        if (sb.Length > 0) {
                            sb.Append (":");
                        sb.Append (b.ToString ("X2"));

                    String mac = sb.ToString ();
                    if (!allZero) {
                    off += len;
                    if (length <= off) {
                Marshal.FreeHGlobal (pLen);
                Marshal.FreeHGlobal (pBuf);
            if (AllMac.ContainsKey (ip)) {
                return AllMac [ip];
        } catch (Exception ex) {
            Console.WriteLine ("Exception in GetMACAddressByIp:" + ex.ToString ());
        return "";