Cross compiling for Cortex A9

Fri Jul 11 10:35:10 UTC 2014

I'm not sure if this is already solved, but if you cross-compile to A9, 
why do you use ARMv5 platform OS?

("target arch","ArchARM {armISA = ARMv5, armISAExt = [], armABI = HARD}")

this looks really strange. armABI HARD, that means FP data in FP regs, 
still no VFP in armISAExt and even armISA set to ARMv5.

For example on my ubuntu 12.04 I do have:

  ("target arch", "ArchARM {armISA = ARMv7, armISAExt = [VFPv3,NEON], 
armABI = HARD}"),

which is right for pandaboard which is dual Cortex-A9.

So, shortly I really do not know if you do not hit some corner case in 
LLVM here. I would certainly suggest especially considering your 
Cortex-A9 target to update your OS to get to what I do have here: 
ARMv7+VFPv3/NEON+ABI HARD.

BTW: Another issue may be that GHC misconfigures on your platform and 
they you will need to tell us more about your target OS...

Cheers,
Karel

On 07/ 8/14 07:51 AM, Michael Jones wrote:
> I am pasting both the info from the HOST and TARGET compilers:
>
> HOST
> ====
>
> [("Project name","The Glorious Glasgow Haskell Compilation System")
> ,("GCC extra via C opts"," -fwrapv")
> ,("C compiler command","/usr/bin/gcc")
> ,("C compiler flags"," -fno-stack-protector -Wl,--hash-size=31
> -Wl,--reduce-memory-overheads")
> ,("ar command","/usr/bin/ar")
> ,("ar flags","q")
> ,("ar supports at file","YES")
> ,("touch command","touch")
> ,("dllwrap command","/bin/false")
> ,("windres command","/bin/false")
> ,("perl command","/usr/bin/perl")
> ,("target os","OSLinux")
> ,("target arch","ArchX86_64")
> ,("target word size","8")
> ,("target has GNU nonexec stack","True")
> ,("target has .ident directive","True")
> ,("target has subsections via symbols","False")
> ,("LLVM llc command","llc")
> ,("LLVM opt command","opt")
> ,("Project version","7.6.3")
> ,("Booter version","7.6.3")
> ,("Stage","2")
> ,("Build platform","x86_64-unknown-linux")
> ,("Host platform","x86_64-unknown-linux")
> ,("Target platform","x86_64-unknown-linux")
> ,("Have interpreter","YES")
> ,("Object splitting supported","YES")
> ,("Have native code generator","YES")
> ,("Support SMP","YES")
> ,("Unregisterised","NO")
> ,("Tables next to code","YES")
> ,("RTS ways","l debug thr thr_debug thr_l thr_p dyn debug_dyn thr_dyn
> thr_debug_dyn thr_debug_p")
> ,("Leading underscore","NO")
> ,("Debug on","False")
> ,("LibDir","/usr/lib/ghc")
> ,("Global Package DB","/usr/lib/ghc/package.conf.d")
> ,("Gcc Linker
> flags","[\"-Wl,--hash-size=31\",\"-Wl,--reduce-memory-overheads\"]")
> ,("Ld Linker flags","[\"--hash-size=31\",\"--reduce-memory-overheads\"]")
> ]
>
>
> TARGET
> =======
>
> [("Project name","The Glorious Glasgow Haskell Compilation System")
> ,("GCC extra via C opts"," -fwrapv")
> ,("C compiler command","arm-poky-linux-gnueabi-gcc")
> ,("C compiler flags"," -fno-stack-protector")
> ,("C compiler link flags","")
> ,("ld command","arm-poky-linux-gnueabi-ld")
> ,("ld flags","")
> ,("ld supports compact unwind","YES")
> ,("ld supports build-id","YES")
> ,("ld supports filelist","NO")
> ,("ld is GNU ld","YES")
> ,("ar command","/usr/bin/ar")
> ,("ar flags","q")
> ,("ar supports at file","YES")
> ,("touch command","touch")
> ,("dllwrap command","/bin/false")
> ,("windres command","/bin/false")
> ,("libtool command","libtool")
> ,("perl command","/usr/bin/perl")
> ,("target os","OSLinux")
> ,("target arch","ArchARM {armISA = ARMv5, armISAExt = [], armABI = HARD}")
> ,("target word size","4")
> ,("target has GNU nonexec stack","False")
> ,("target has .ident directive","True")
> ,("target has subsections via symbols","False")
> ,("Unregisterised","NO")
> ,("LLVM llc command","llc")
> ,("LLVM opt command","opt")
> ,("Project version","7.8.2")
> ,("Booter version","7.6.3")
> ,("Stage","1")
> ,("Build platform","x86_64-unknown-linux")
> ,("Host platform","x86_64-unknown-linux")
> ,("Target platform","arm-unknown-linux")
> ,("Have interpreter","YES")
> ,("Object splitting supported","NO")
> ,("Have native code generator","NO")
> ,("Support SMP","YES")
> ,("Tables next to code","YES")
> ,("RTS ways","l debug thr thr_debug thr_l ")
> ,("Support dynamic-too","YES")
> ,("Support parallel --make","YES")
> ,("Dynamic by default","NO")
> ,("GHC Dynamic","NO")
> ,("Leading underscore","NO")
> ,("Debug on","False")
> ,("LibDir","/usr/local/lib/arm-unknown-linux-gnueabi-ghc-7.8.2")
> ,("Global Package
> DB","/usr/local/lib/arm-unknown-linux-gnueabi-ghc-7.8.2/package.conf.d")
> ]
>
>
>
>
> On Jul 7, 2014, at 10:42 PM, Carter Schonwald
> <carter.schonwald at gmail.com <mailto:carter.schonwald at gmail.com>> wrote:
>
>> could you share the output of ghc --info?
>>
>>
>> On Tue, Jul 8, 2014 at 12:10 AM, Michael Jones <mike at proclivis.com
>> <mailto:mike at proclivis.com>> wrote:
>>
>>     I am having problems building a GHC cross compiler for Linux
>>     (Yocto on a Wandboard) running on a Cortex A9, and need some
>>     advice on how to debug it.
>>
>>     The cross compiler produces an executable that runs on the Target,
>>     but fails to print. So I need help coming up with a strategy to
>>     narrow down the root cause.
>>
>>     Some details:
>>
>>     The application:
>>
>>     main = do
>>     putStrLn "Haskell start"
>>
>>
>>     The command line options work. The program runs, and I can step
>>     through assembly. Debug data is printed to the console. But
>>     putStrLn fails, and program enters an infinite loop.
>>
>>     I compile my app as follows:
>>
>>     arm-unknown-linux-gnueabi-ghc -debug -static Main.hs
>>
>>     Using -threaded does not fix the problem.
>>
>>     Let me compare debug data from a run on my HOST, with a run on my
>>     TARGET. First, a run from my HOST:
>>
>>     created capset 0 of type 2
>>     created capset 1 of type 3
>>     cap 0: initialised
>>     assigned cap 0 to capset 0
>>     assigned cap 0 to capset 1
>>     cap 0: created thread 1
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (suspended while making a foreign call)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (finished)
>>     cap 0: created thread 2
>>     cap 0: running thread 2 (ThreadRunGHC)
>>     cap 0: thread 2 stopped (finished)
>>     cap 0: starting GC
>>     cap 0: GC working
>>     cap 0: GC idle
>>     cap 0: GC done
>>     cap 0: GC idle
>>     cap 0: GC done
>>     cap 0: GC idle
>>     cap 0: GC done
>>     cap 0: GC idle
>>     cap 0: GC done
>>     cap 0: all caps stopped for GC
>>     cap 0: finished GC
>>     removed cap 0 from capset 0
>>     removed cap 0 from capset 1
>>     cap 0: shutting down
>>     deleted capset 0
>>     deleted capset 1
>>
>>     And, it prints properly. So this is my referenced for what it
>>     should do on the TARGET.
>>
>>     When I run on my TARGET, I get:
>>
>>     created capset 0 of type 2
>>     created capset 1 of type 3
>>     cap 0: initialised
>>     assigned cap 0 to capset 0
>>     assigned cap 0 to capset 1
>>     cap 0: created thread 1
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (yielding)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (yielding)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (yielding)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (yielding)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (yielding)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (yielding)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (stack overflow)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (stack overflow)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (stack overflow)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (yielding)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (stack overflow)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (stack overflow)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (stack overflow)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (yielding)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (stack overflow)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (heap overflow)
>>     cap 0: starting GC
>>     cap 0: GC working
>>     cap 0: GC idle
>>     cap 0: GC done
>>     cap 0: GC idle
>>     cap 0: GC done
>>     cap 0: GC idle
>>     cap 0: GC done
>>     cap 0: all caps stopped for GC
>>     cap 0: finished GC
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (yielding)
>>     cap 0: running thread 1 (ThreadRunGHC)
>>     cap 0: thread 1 stopped (stack overflow)
>>     ...
>>
>>     And the debug data goes on forever, just as debugging assembly
>>     demonstrated an infinite loop.
>>
>>     Clearly, the following does not occur:
>>
>>     cap 0: thread 1 stopped (suspended while making a foreign call)
>>
>>     And there are overflows.
>>
>>     If I had to guess, it is possible that some code is in a loop
>>     retrying to foreign call, and failing. Certainly, it is in some
>>     kind of a loop, because I found a place I can put a break point
>>     and and telling GDB to continue will cause the break over and over
>>     at the same place. So somewhere there is a loop.
>>
>>     I can step through the application with GDB and see names of files
>>     and offsets in assembly. But without a true source code debug,
>>     that is a bit rough, especially for someone that does not know the
>>     RTS code. If there was a way to compile such that C source code
>>     was available and a place to break, that would help. However, I
>>     suspect since it never makes a foreign call, there is no place in
>>     C to place the breakpoint anyway. So I am also assuming there is
>>     no direct way to debug with GDB.
>>
>>     But, I can see debug output printed to the console. My hope is
>>     there is a way to enable more printing, or a place I can add more
>>     print functions to help find the problem.
>>
>>     So I think I need one of the following:
>>
>>     - A solution from someone that has seen this before, perhaps on
>>     the iPhone
>>     - How to enable more debug logging
>>     - Where in the source code to add debug statements to narrow down
>>     the problem
>>
>>     Thanks for any help you can give.
>>
>>     Mike
>>
>>
>>     _______________________________________________
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>>     Glasgow-haskell-users at haskell.org
>>     <mailto:Glasgow-haskell-users at haskell.org>
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>>
>>
>
>
>
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