Runtime error using LLVM bitcode execution

[Simon Marlow]

You need to run it against the assembly file (.s) that LLVM generates, 
not the .ll file.

Cheers,
Simon

On 28/02/2014 08:48, Benzinger, Ralph wrote:
> Hello Simon,
>
> Thanks for your suggestion!  I ran the LLVM mangler against the hfun.ll file, but it didn't make any changes to the code at all.  (My understanding is that I can leave the hfun_stub alone.)
>
> Am I missing something?
>
> Regards
> Ralph
>
>
> -----Original Message-----
> From: Simon Marlow [mailto:marlowsd at gmail.com]
> Sent: Mittwoch, 26. Februar 2014 09:11
> To: Benzinger, Ralph; ghc-devs at haskell.org
> Subject: Re: Runtime error using LLVM bitcode execution
>
> My guess is that this isn't working because GHC needs to post-process
> the assembly generated by LLVM to support tables-next-to-code.  You
> could extract this phase from GHC (it's just one module, in
> compiler/llvmGen/LlvmMangler.hs) and run it as a standalone program.
>
> Cheers,
> Simon
>
> On 21/02/2014 16:02, Benzinger, Ralph wrote:
>> Hello,
>>
>> My apologies in advance if this mailing list is not the appropriate
>> address for posting my problem with the GHC runtime, but it seemed
>> like the best option on the GHC home page.
>>
>> I'm trying to execute standalone Haskell functions exported via FFI
>> and compiled as LLVM bitcode.  Unfortunately, all my efforts yield the
>> following runtime error:
>>
>> lu003107:~/hs-bitcode> ./bce_so hsallinone.bc
>> hs_init complete
>> hs_add_root complete
>> hsallinone: internal error: stg_ap_p_ret
>>       (GHC version 7.6.3 for x86_64_unknown_linux)
>>       Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
>> 0  bce_so               0x0000000000d6b310
>> 1  bce_so               0x0000000000d6b53b
>> 2  bce_so               0x0000000000d6ba1c
>> 3  libpthread.so.0      0x00007f7683298800
>> 4  libc.so.6            0x00007f7682592b35 gsignal + 53
>> 5  libc.so.6            0x00007f7682594111 abort + 385
>> 6  libHSrts-ghc7.6.3.so 0x00007f7683f6ca21 rtsFatalInternalErrorFn + 177
>> 7  libHSrts-ghc7.6.3.so 0x00007f7683f6cce1 barf + 145
>> 8  libHSrts-ghc7.6.3.so 0x00007f7683f8a24a stg_ap_p_info + 130
>> Stack dump:
>> 0.      Program arguments: ./bce_so hsallinone.bc
>> Aborted
>>
>> This is what I do:
>>
>> I have a function hfun.hs that exports a function
>>
>>       foreign export ccall hfun :: CInt -> CInt
>>
>> and a wrapper cmain.c that calls this function:
>>
>>       #include <HsFFI.h>
>>       #include "hfun_stub.h"
>>       extern void __stginit_HFun(void);
>>       #include <stdio.h>
>>
>>       int main(int argc, char *argv[])
>>       {
>> 	hs_init(&argc, &argv);
>> 	printf("hs_init complete\n");
>>
>> 	hs_add_root(__stginit_HFun);
>>       	printf("hs_add_root complete\n");
>>
>>       	int i = hfun(42);
>>       	printf("hfun(42) = %d\n", i);
>>
>>       	hs_exit();
>>       	return 0;
>>       }
>>
>> To generate a callable bitcode file I use these commands:
>>
>>       $ ghc -S -keep-llvm-files -keep-tmp-files hfun.hs
>>       $ llvm-as hfun.ll
>>       $ cp /tmp/... hfun_stub.c
>>       $ clang -c -emit-llvm -I /opt/ghc/lib/ghc-7.6.3/include hfun_stub.c
>>       $ clang -c -emit-llvm -I /opt/ghc/lib/ghc-7.6.3/include cmain.c
>>       $ llvm-link cmain.bc hfun_stub.bc hfun.bc -o hsallinone.bc
>>
>> My main program "bce_so" loads the linked bitcode and feeds it to the
>> LLVM execution engine.  All required Haskell runtime libraries are
>> linked dynamically against bce_so.
>>
>> Could you kindly provide some insight on whether this runtime error is
>> due to a bug with GHC (unlikely) or rather some negligence in my
>> setup?  Or does the issue highlight some principal limitation in my
>> (admittedly somewhat naive) approach of using LLVM -- threading
>> support, maybe?
>>
>> Note that compiling hfun.hs/cmain.c into a .so and executing
>> everything natively using ldload() works flawlessly.
>>
>> Regards
>> Ralph
>>