[LLVMdev] Code generation support in llvm for windows phone

Sun Jun 8 22:53:07 PDT 2014

yeah .. the app runs perfectly. Thank you so much Saleem.
Regards,
Kashyap

On Sun, Jun 8, 2014 at 1:08 PM, C K Kashyap <ckkashyap at gmail.com> wrote:

> Wow ... I did a git pull on llvm and clang compiled my c file
> clang  -target thumbv7-windows -c  -O0  a.c -oa.obj
> dumpbin /all on a.obj now shows "thumb instructions" ..... I'll try
> running this tomorrow and post back.
>
> Regards,
> Kashyap
>
>
>
> On Sun, Jun 8, 2014 at 9:39 AM, Saleem Abdulrasool <compnerd at compnerd.org>
> wrote:
>
>> On Sat, Jun 7, 2014 at 8:03 PM, C K Kashyap <ckkashyap at gmail.com> wrote:
>>
>>> Thank you so much Saleem,
>>> The target is Windows phone 8.1 (ARM). I'll update the crash details
>>> tomorrow.
>>>
>>
>> Please rebuild the tree after SVN r210415 when you test it again.  It
>> seems that link.exe needs the IMAGE_SCN_MEM_16BIT set in order to select
>> the function as a thumb function rather than silently assuming that all
>> functions are thumb (which was something that I suspected but hadn't tested
>> since I haven't been using that linker for my testing).
>>
>> If you were seeing an "Invalid Instruction" exception, that was caused by
>> the application switching into ARM mode execution (rather than staying in
>> thumb mode as it should).
>>
>> Please let met know what the result is with your test, as I do want to
>> ensure that this does play well with the Visual Studio toolchain.
>>
>> One big problem is that I have to use a physical windows phone for
>>> execution.
>>>
>> I wonder if it is possible to execute such "exes" using qemu.
>>>
>>
>> Please let me know if you get that to work somehow (I don't know if there
>> is a way to do that currently).
>>
>>
>>> Regards,
>>> Kashyap
>>>
>>>
>>>
>>> On Sun, Jun 8, 2014 at 2:53 AM, Saleem Abdulrasool <
>>> compnerd at compnerd.org> wrote:
>>>
>>>> On Sat, Jun 7, 2014 at 10:06 AM, C K Kashyap <ckkashyap at gmail.com>
>>>> wrote:
>>>>
>>>>> Hi Saleem,
>>>>> I have a similar situation - I'd appreciate your inputs on it. I
>>>>> noticed that the obj file generated using llvm does not contain "thumb"
>>>>> instructions. I suspect that is what is causing runtime crash for me.
>>>>>
>>>>>
>>>>> Here's what I've tried -
>>>>> Start with a.c (on my linux machine where I have llvm/clang built as
>>>>> of yesterday)
>>>>>                       int add(int i, int j) {int k = i + j; return k; }
>>>>> clang  -S  -O0  a.c
>>>>>
>>>>
>>>> This targets the default target, which may not necessarily be the
>>>> target that you want.
>>>>
>>>>
>>>>> llc -filetype=obj -mtriple=thumbv7-windows -O0 a.ll
>>>>>
>>>>
>>>> This is a bit round-about to generate the object-file.
>>>>
>>>> You can actually generate the object file directly from clang at this
>>>> point, which may not have been the case when you first started looking at
>>>> this.
>>>>
>>>> $ clang -target armv7-windows -c a.c -o a.obj
>>>>
>>>> If you look at the generated assembly, you will find that it will
>>>> generate a thumb function, even though the object file may be missing the
>>>> appropriate flag in the case of the public llvm repository (Ill look into
>>>> that btw).
>>>>
>>>> I get a.obj from the above steps.
>>>>>
>>>>> I take this a.obj over to my windows 8.1 machine where I have VS2013
>>>>> update 2 installed
>>>>>
>>>>> I open up a command window and run
>>>>> C:\Users\kck\arm>"c:\Program Files (x86)\Microsoft Visual Studio
>>>>> 12.0\vc\bin\x86_arm\vcvarsx86_arm.bat"
>>>>>
>>>>> I create a file file m.c
>>>>> int main() { return add(20,30);}
>>>>>
>>>>
>>>> This might cause an issue.  You are not providing a declaration for the
>>>> symbol.  If cl ends up converting it to a dllimport'ed symbol, the
>>>> generated application will not execute.
>>>>
>>>>
>>>>> I build the whole thing like this -
>>>>>
>>>>> cl m.c a.obj
>>>>>
>>>>
>>>> That seems right; I will note that all my testing with cl has been with
>>>> /MD.
>>>>
>>>>
>>>>> Things seem  to work fine and m.exe gets generated.
>>>>>
>>>>> However I noticed a difference in the dumpbin output for a.obj and
>>>>> m.obj - In m.obj, I can see "Thumb instructions" where as in a.obj, I don't
>>>>> see that.
>>>>>
>>>>
>>>> I'll look into that, but, I suspect that this is not the cause of the
>>>> crash.
>>>>
>>>>
>>>>> I'd appreciate any pointers on this.
>>>>>
>>>>
>>>> Can you specify what the target environment is?  (Device, Windows
>>>> version, etc).
>>>>
>>>> Actual details of the crash may also be relevant.  Also of interest
>>>> would be how you are loading the generated binary onto the device.  The
>>>> only way that I know of accomplishing that involves the use of Visual
>>>> Studio's remote debugging functionality.
>>>>
>>>>
>>>>> Regards,
>>>>> Kashyap
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Fri, May 30, 2014 at 10:45 PM, Saleem Abdulrasool <abdulras at fb.com>
>>>>> wrote:
>>>>>
>>>>>>
>>>>>> On May 28, 2014, at 5:18 AM, Rajat Mahajan <rmahajan at adobe.com>
>>>>>> wrote:
>>>>>>
>>>>>> > I am talking about Windows Mobile 8 and 8.1 and not CE.
>>>>>> > Not sure though that the Windows 8 (ARM NT) is similar to Windows
>>>>>> Mobile 8 platform.
>>>>>> >
>>>>>> > I used the following command to generate the obj file
>>>>>> >    Llc.exe -mtriple=thumbv7-windows  -filetype=obj  <some_name>.bc
>>>>>> >
>>>>>> > The object file generated in the above object doesn't get linked
>>>>>> when I try to link it with the windows mobile library as it fails to
>>>>>> recognize the object format.  ( Not a valid object file )
>>>>>> >
>>>>>> > Hope I am clear.
>>>>>>
>>>>>> Unfortunately, you have merely repeated your previous statement.  I
>>>>>> don’t have enough here to diagnose nor even speculate what is going on.
>>>>>>
>>>>>> If you can provide the object file, it would be helpful as I am
>>>>>> unable to reproduce this issue.  Although, I ran it via clang, I see no
>>>>>> reason that the output would be different as the backend is the same.
>>>>>>
>>>>>> The triple is certainly correct (particularly for llc, clang will
>>>>>> treat armv7-windows as thumbv7-windows).  How did you generate the bit
>>>>>> code?  My testing has usually started from C or LLVM IR rather than bit
>>>>>> code, but, I suspect that shouldn’t be a real issue.
>>>>>>
>>>>>> With the given information, the only thing that comes to mind is that
>>>>>> your environment is setup improperly, resulting in the wrong link.exe being
>>>>>> invoked.
>>>>>>
>>>>>> > ~rajat
>>>>>> >
>>>>>> > -----Original Message-----
>>>>>> > From: Saleem Abdulrasool [mailto:abdulras at fb.com]
>>>>>> > Sent: Friday, May 16, 2014 11:23 PM
>>>>>> > To: Rajat Mahajan
>>>>>> > Cc: llvmdev at cs.uiuc.edu
>>>>>> > Subject: Re: [LLVMdev] Code generation support in llvm for windows
>>>>>> phone
>>>>>> >
>>>>>> >
>>>>>> > On May 16, 2014, at 6:53 AM, Rajat Mahajan <rmahajan at adobe.com>
>>>>>> wrote:
>>>>>> >
>>>>>> >> Hi,
>>>>>> >>
>>>>>> >> Is there support available in llc to convert llvm bytecode to
>>>>>> Windows Mobile binary?
>>>>>> >> I have tried triples like arm-pc-win32 , thumbv7-window ... but
>>>>>> the object file generated is not getting linked to the windows native
>>>>>> project.
>>>>>> >> Any pointers will be greatly appreciated?
>>>>>> >
>>>>>> > As Reid mentioned, I have been working on this recently.  Just to
>>>>>> make sure that we are talking about the same environment, I assume that you
>>>>>> are talking about Windows 8 (ARM NT) rather than the Windows CE based
>>>>>> environment.
>>>>>> >
>>>>>> > Can you please explain what exactly you mean by "the object file
>>>>>> generated is not getting linked to the windows native project".  The object
>>>>>> file that we generate should be pretty compatible with MSVC.  If you have
>>>>>> specific cases where we are generating something that is incompatible, I
>>>>>> would be quite interested in hearing about that.
>>>>>> >
>>>>>> >> Thanks,
>>>>>> >> ~rajat
>>>>>> >> _______________________________________________
>>>>>> >> LLVM Developers mailing list
>>>>>> >> LLVMdev at cs.uiuc.edu
>>>>>> https://urldefense.proofpoint.com/v1/url?u=http://llvm.cs.uiuc.edu/&k=ZVNjlDMF0FElm4dQtryO4A%3D%3D%0A&r=CchYc4lrV44%2BZqxZADw0BQ%3D%3D%0A&m=4sS%2FRJsOxjeRZpxwDsr85CHzLMrTV5IeD%2Bf2OnxlCFY%3D%0A&s=64253b311de373a46904eada51eb8c9f732f8f65d14f0551223b2a7c769f135a
>>>>>> >>
>>>>>> https://urldefense.proofpoint.com/v1/url?u=http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev&k=ZVNjlDMF0FElm4dQtryO4A%3D%3D%0A&r=CchYc4lrV44%2BZqxZADw0BQ%3D%3D%0A&m=4sS%2FRJsOxjeRZpxwDsr85CHzLMrTV5IeD%2Bf2OnxlCFY%3D%0A&s=5c75919fb4cc3458c6e733d0d672d937dca015122c56ab7b826bc6b5ae74a594
>>>>>> >
>>>>>> > --
>>>>>> > Saleem Abdulrasool
>>>>>> > abdulras (at) fb (dot) com
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>>
>>>>>> --
>>>>>> Saleem Abdulrasool
>>>>>> abdulras (at) fb (dot) com
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> LLVM Developers mailing list
>>>>>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> LLVM Developers mailing list
>>>>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Saleem Abdulrasool
>>>> compnerd (at) compnerd (dot) org
>>>>
>>>
>>>
>>
>>
>> --
>> Saleem Abdulrasool
>> compnerd (at) compnerd (dot) org
>>
>
>
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