llvm dev - Jul 2009 - [LLVMdev] build failure on ARM linux

2009/6/30 Andrew Haley <aph at redhat.com>
> Nick Lewycky wrote:
> > I'm seeing this new build failure, starting some time yesterday on
ARM:
> >
> > make[3]: Entering directory
`/home/nlewycky/llvm/tools/llvmc/driver'
> > llvm[3]: Linking Debug executable llvmc
> > g++ -DLLVMC_BUILTIN_PLUGIN_1=Base -DLLVMC_BUILTIN_PLUGIN_2=Clang
> -I/home/nlewycky/llvm/include -I/home/nlewycky/llvm/tools/llvmc/driver
>  -D_DEBUG  -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS -g
> -fPIC  -Woverloaded-virtual   -pedantic -Wno-long-long -Wall -W
> -Wno-unused-parameter -Wwrite-strings  -lCompilerDriver -g  -Wl,-R
> -Wl,/home/nlewycky/llvm/Debug/bin -Wl,-export-dynamic
> -L/home/nlewycky/llvm/Debug/lib -L/home/nlewycky/llvm/Debug/lib  -o
> /home/nlewycky/llvm/Debug/bin/llvmc
>  /home/nlewycky/llvm/tools/llvmc/driver/Debug/Main.o -lplugin_llvmc_Base
> -lplugin_llvmc_Clang \
> >            -lpthread -ldl -lm
> > /usr/bin/ld: /home/nlewycky/llvm/Debug/bin/llvmc: hidden symbol
> `__sync_val_compare_and_swap_4' in
> /usr/lib/gcc/arm-linux-gnueabi/4.3.3/libgcc.a(linux-atomic.o) is referenced
> by DSO
> > /usr/bin/ld: final link failed: Nonrepresentable section on output
> > collect2: ld returned 1 exit status
> > make[3]: *** [/home/nlewycky/llvm/Debug/bin/llvmc] Error 1
> >
> > This is with LLVM being built by the system compiler (GCC 4.3.3-10
> > Debian). I'm not sure what to make of this. Would it be due to the
> > atomics used for mutexes?
>
> Yes.  It's just a matter of defining __sync_val_compare_and_swap_4:
>
> http://gcc.gnu.org/svn/gcc/trunk/gcc/config/arm/linux-atomic.c
>
The program is supposed to define it? LLVM doesn't directly call
__sync_val_compare_and_swap_4, so either the system headers #define
something else to it or gcc lowers another call to that. In either case, why
is it declared HIDDEN?

Nick

>
> Andrew.
> _______________________________________________
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> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
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Nick Lewycky wrote:
> 2009/6/30 Andrew Haley <aph at redhat.com <mailto:aph at
redhat.com>>
> 
>     Nick Lewycky wrote:
>     > I'm seeing this new build failure, starting some time
yesterday on
>     ARM:
> 
>     Yes.  It's just a matter of defining __sync_val_compare_and_swap_4:
> 
>     http://gcc.gnu.org/svn/gcc/trunk/gcc/config/arm/linux-atomic.c
> 
> 
> The program is supposed to define it? LLVM doesn't directly call
> __sync_val_compare_and_swap_4, so either the system headers #define
> something else to it or gcc lowers another call to that.
gcc lowers atomic operations to that.  It's part of libgcc now.
> In either case, why is it declared HIDDEN?
I'm not sure.

Andrew.

llvm/lib/System/Atomic.cpp contains the call to 
__sync_val_compare_and_swap that lowers to the missing 
__sync_val_compare_and_swap_4 GCC intrinsic.

The same file contains several other __sync_* calls  and all these has 
to be implemented if we want to be able to compile llvm on linux/ARM 
with GCC versions below < 4.4

xerxes at labbserver:~/llvm$ grep _sync lib/*/*
lib/System/Atomic.cpp:  __sync_synchronize();
lib/System/Atomic.cpp:  return __sync_val_compare_and_swap(ptr, 
old_value, new_value);
lib/System/Atomic.cpp:  return __sync_add_and_fetch(ptr, 1);
lib/System/Atomic.cpp:  return __sync_sub_and_fetch(ptr, 1);
lib/System/Atomic.cpp:  return __sync_add_and_fetch(ptr, val);

Cheers
Xerxes

Andrew Haley skrev:
> Nick Lewycky wrote:
>   
>> 2009/6/30 Andrew Haley <aph at redhat.com <mailto:aph at
redhat.com>>
>>
>>     Nick Lewycky wrote:
>>     > I'm seeing this new build failure, starting some time
yesterday on
>>     ARM:
>>
>>     Yes.  It's just a matter of defining
__sync_val_compare_and_swap_4:
>>
>>     http://gcc.gnu.org/svn/gcc/trunk/gcc/config/arm/linux-atomic.c
>>
>>
>> The program is supposed to define it? LLVM doesn't directly call
>> __sync_val_compare_and_swap_4, so either the system headers #define
>> something else to it or gcc lowers another call to that.
>>     
>
> gcc lowers atomic operations to that.  It's part of libgcc now.
>
>   
>> In either case, why is it declared HIDDEN?
>>     
>
> I'm not sure.
>
> Andrew.
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>

Andrew Haley wrote:
> Nick Lewycky wrote:
>> 2009/6/30 Andrew Haley <aph at redhat.com <mailto:aph at
redhat.com>>
>>
>>     Nick Lewycky wrote:
>>     > I'm seeing this new build failure, starting some time
yesterday on
>>     ARM:
>>
>>     Yes.  It's just a matter of defining
__sync_val_compare_and_swap_4:
>>
>>     http://gcc.gnu.org/svn/gcc/trunk/gcc/config/arm/linux-atomic.c
>>
>>
>> The program is supposed to define it? LLVM doesn't directly call
>> __sync_val_compare_and_swap_4, so either the system headers #define
>> something else to it or gcc lowers another call to that.
> 
> gcc lowers atomic operations to that.  It's part of libgcc now.
> 
>> In either case, why is it declared HIDDEN?
> 
> I'm not sure.
This is a known bug in gcc: see
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40133

We're trying to get it fixed.

Andrew.