[Vm-dev] Android VM

[Clément Bera]

On Wed, Oct 5, 2016 at 5:29 PM, Santiago Bragagnolo <
santiagobragagnolo at gmail.com> wrote:

>
> Hi All!
> I'm working on the Android VM. (https://github.com/sbragagnolo/pharo-vm)
>  So far I made my way on my own(I have a working compilation of the stack
> vm for android functional, but without uffi and quite slow ). But now i
> have a problem that I don't understand at all, i would like if someone can
> point me a clue :).
>
> Im working on the VM+Jit for android. The device i'am using to test is a
> wiko pulp 4g[1], processor Quad-core 1.2 GHz Cortex-A53 with support for
> 32bits/64bits instructions [2]
>
> I am compiling the VM with the following maker options:
>
> *maker options: #(*
> * ObjectMemory Spur32BitCoMemoryManager*
> * FailImbalancedPrimitives false*
> * CogCompilerClass CogOutOfLineLiteralsARMCompiler*
> * ISA ARMv5).*
>
> After some manual post processing (related to an other question that i
> will do in other thread), I arrive to compile and deploy the application in
> to my device.
>
> But when I open the application I am having the following assertion
> failure ( defined in sqCogStackAlignment.h ),
>
>   *assert((getfp() & STACK_ALIGN_MASK) == STACK_FP_ALIGNMENT);*
>
>  and failing in the second call for the assertion, on the generated
> function *generateStackPointerCapture* on the generated file
> *cogitARMv5.c*, based on the method
> *Cogit>>#generateStackPointerCapture, *and not finishing the process, but
> just failing many other times in the same assertion (not sure if on the
> same function)
>
>
> *=====================*
> static void generateStackPointerCapture(void) {
>     sqInt oldMethodZoneBase;
>     sqInt oldTrampolineTableIndex;
>
> /* For the benefit of the following assert, assume the minimum at first. */
>         cFramePointerInUse = 0;
> assertCStackWellAligned();
> oldMethodZoneBase = methodZoneBase;
> oldTrampolineTableIndex = trampolineTableIndex;
> generateCaptureCStackPointers(1);
> ceCaptureCStackPointers();
> if (!((cFramePointerInUse = isCFramePointerInUse()))) {
> methodZoneBase = oldMethodZoneBase;
> trampolineTableIndex = oldTrampolineTableIndex;
> generateCaptureCStackPointers(0);
> }
> assertCStackWellAligned();   *// it fails Here*
> }
> *======================*
>
> Here I'm lacking understanding, and even when after some painful time I
> arrived to be able to debug on my device when I leave the debugger just to
> run and randomly interrupt the process to know where is failing constantly
> (i'm almost sure that is an infinite loop, because of the standard output)
> It just die, or it stops without showing code, since is the code stored on
> the assembly files.
>
> I have two obvious questions:
>
>   1) does the prepareVmMaker method that I defined makes sense?
>

Look strange.

FailImbalancedPrimitives false => for the VM without the JIT. The default
is true, just write nothing instead.

CogCompilerClass CogOutOfLineLiteralsARMCompiler ISA ARMv5 => The VM is
generated for all back-ends on the word size. Just write nothing instead.

I believe maker options: #(ObjectMemory Spur32BitCoMemoryManager) is enough.


>   2) any body can give me a hint about how to debug better this problem?
>

> And finally, does any body have a hint in general about what can it be?
>
> [1] http://www.gsmarena.com/wiko_pulp_4g-7811.php
> [2] http://www.arm.com/products/processors/cortex-a/cortex-
> a53-processor.php
>
>
>
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