……………………

    0x01e394ac monoeg_g_log + 208 6 TrackAboutIOS
    0x01d11664 get_numerous_trampoline + 160 7 TrackAboutIOS
    ……………………
    =================================================================
          Got a SIGSEGV while executing native code. This usually indicates
           a fatal error in the mono runtime or one of the native libraries 
          used by your application.
   =================================================================

On device we generate all the necessary code at build time in a process known as Ahead of Time compilation (similar to Microsoft's ngen), because we're not allowed to jit code on devices. Unfortunately there are a few things that cannot be determined statically - for instance generic interfaces might need different vtables depending on which type the interface is instantiated with. (For this case it is technically possible to determine the maximum number of vtables, but the number would be potentially enormous - multiply the number of generic interfaces times the number of types in your app...). We cannot allocate memory for these vtables dynamically at runtime, so we've picked a reasonable default and allow the user to increase this value if they run into issues. This is the basic theory for the trampolines (the exact problem is a bit different, depending on the type of trampolines, but that's not really important).

So you can add as many trampolines as you want, but memory usage will increase. That's also all there is to it: the app will not get slower (unless if the increased memory usage causes it to run slower, due to out-of-memory warnings, etc). It also means that you only have to increase the number of trampolines of the type you're actually having problems with, if you increase the others you'll increase the size of your executable needlessly.

因為mono不允許在蘋果設備上即時編譯代碼，所以在編譯的時候mono會通過AOT編譯技術直接編譯為ARM匯編代碼。但在編譯的時候仍有一些無法靜態確定的事情：例如泛型接口可能需要不同的虛擬表（運行時存放執行方法的集合），這取決于接口被實例化時的類型。（對于這種情況，從技術上講確定虛擬表的最大數量是可能的，但是這數量可能會是龐大的--即泛型接口數乘以應用中類型數）……我們無法為這些虛擬表在運行時動態的分配內存，所以我們指定了一個合理的默認值并且允許用戶在運行時出現問題的情況下增加默認值。這就是蹦床的基本理論（實際情況略微不同，這依賴于蹦床數的類型，但這并不重要）

所以你可以按你的需要盡可能的增加蹦床數，但是內存的使用會增加。 應用一般不會變慢（除非內存的使用增多導致了內存不足，從而引起運行變慢）。這也同時意味著你只僅僅需要增加發生問題那塊對應的蹦床類型的數目。如果你增加了其他蹦床類型的數目，你也會不必要的增多了執行的體積。

Ran out of trampolines of type 0
If you get this message while running device,  You can create more type 0 trampolines (type SPECIFIC) by modifying your project options "iPhone Build" section.  You want to add extra arguments for the Device build targets:

-aot "ntrampolines=2048"

The default number of trampolines is 1024.  Try increasing this number until you have enough for your application.

Ran out of trampolines of type 1
If you make heavy use of recursive generics, you may get this message on device.  You can create more type 1 trampolines (type RGCTX) by modifying your project options "iPhone Build" section.  You want to add extra arguments for the Device build targets:

-aot "nrgctx-trampolines=2048"

The default number of trampolines is 1024.  Try increasing this number until you have enough for your usage of generics.

Ran out of trampolines of type 2
If you make heavy use interfaces, you may get this message on device.  You can create more type 2 trampolines (type IMT Thunks) by modifying your project options "iPhone Build" section.  You want to add extra arguments for the Device build targets:

-aot "nimt-trampolines=512"

The default number of IMT Thunk trampolines is 128.  Try increasing this number until you have enough for your usage of interfaces.

Ran out of trampolines of type 0 

如果你再運行時，輸出這個錯誤，你可以在項目option--iphone build處添加額外的參數-aot "ntrampolines=2048" 

這個參數默認值為1024，試著增加這個值直到滿足你的應用的需求。

Ran out of trampolines of type 1 

如果你使用了過多的泛型嵌套，如List<T>中還有List<T>成員，你可以同上通過添加額外的參數-aot "nrgctx-trampolines=2048" 來解決。

蹦床類型1的默認值為1024.

Ran out of trampolines of type 2 

如果你界面操作頻繁，你可以通過添加額外的參數-aot "nimt-trampolines=512" 來解決。

這里的默認值為128.