Cross compiling for Cortex A9
Michael Jones
mike at proclivis.com
Tue Jul 8 13:25:12 UTC 2014
That doc says:
...This will usually manifest itself as a failure of dll-split during the build process with internal error: evacuate(static): strange closure type 0.
Which does not happen when I build.
Until this is fixed, the newer gold linker will be the only supported linker with GHC on ARM (at least when tables-next-to-code is enabled). GHC now checks that the linker being used isn’t affected by the bug in question, so hopefully users won’t be affected beyond needing to switch linkers.
And I don't get an error indicating this bug unless it is a warning missed in the massive build output.
So I assumed all was fixed. Nonetheless, I'll dig into the linker notes a bit more. Perhaps I should just try the gold linker if Ben does not respond to this enquiry.
Mike
Sent from my iPad
> On Jul 8, 2014, at 12:03 AM, Carter Schonwald <carter.schonwald at gmail.com> wrote:
>
> hrmmm, i seem to recall it being said that you need to use the GOLD linker on ARM. (i think some of this is detailed in http://bgamari.github.io/posts/2014-03-06-compiling-ghc-7.8-on-arm.html )
>
> ,("ld command","arm-poky-linux-gnueabi-ld")
> is that GOLD?
>
>
>> On Tue, Jul 8, 2014 at 1:51 AM, Michael Jones <mike at proclivis.com> 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> wrote:
>>>
>>> could you share the output of ghc --info?
>>>
>>>
>>>> On Tue, Jul 8, 2014 at 12:10 AM, Michael Jones <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
>>>>
>>>>
>>>> _______________________________________________
>>>> Glasgow-haskell-users mailing list
>>>> Glasgow-haskell-users at haskell.org
>>>> http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
>
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