llvm dev - Mar 2009 - [LLVMdev] Consumer ARM platform suitable for LLVM development?

On Mar 11, 2009, at 9:44 PM, Misha Brukman wrote:
> The problem I've had is building an LLVM cross-compiler from Linux/ 
> x86 to Linux/ARM (as has another llvm-dev poster).  Someone  
> mentioned to me off-list that he managed to get it to build, but I  
> haven't been able to reproduce the build using his instructions  
> (I'll post my results in another thread).
I've been successfully experimenting with an arm-softfloat-linux-gnu  
cross-compiler at the time of llvm 2.1. The easiest way to get this  
working is to use Dan Kegel's crosstool to build a regular gcc  
toolchain. This will give you binutils, libgcc, and glibc, which you  
will need anyway.

Building llvm-gcc was relatively painless. The only problem I've  
encountered was that my target had no hardware floating point support  
and the endianess for the softfloat implementation (libgcc) differed  
from integer endianess, which required some patches at the llvm side.  
I have not checked if this is still necessary. If you run into the  
same problems, I would be happy to share the patch (which I have  
updated to llvm 2.4 at some point).

-
Dietmar

[1] http://www.kegel.com/crosstool/


---------------------------------------------------------------------
Dietmar Ebner
CD Laboratory - Compilation Techniques for Embedded Processors
Institut fuer Computersprachen  E: ebner at complang.tuwien.ac.at
Technische Universitaet Wien    T: (+431) 58801-58521
Argentinierstrasse 8 / E1851    F: (+431) 58801-18598
1040 Wien, Austria              W: www.complang.tuwien.ac.at/cd/ebner

On Thu, Mar 12, 2009 at 6:17 AM, Dietmar Ebner
<ebner at complang.tuwien.ac.at>wrote:
> On Mar 11, 2009, at 9:44 PM, Misha Brukman wrote:
> > The problem I've had is building an LLVM cross-compiler from
Linux/
> > x86 to Linux/ARM (as has another llvm-dev poster).  Someone
> > mentioned to me off-list that he managed to get it to build, but I
> > haven't been able to reproduce the build using his instructions
> > (I'll post my results in another thread).
>
> I've been successfully experimenting with an arm-softfloat-linux-gnu
> cross-compiler at the time of llvm 2.1. The easiest way to get this
> working is to use Dan Kegel's crosstool to build a regular gcc
> toolchain. This will give you binutils, libgcc, and glibc, which you
> will need anyway.

I've been trying to build for the target arm-none-linux-gnueabi, using the
appropriate pre-built CodeSourcery toolchain, hence avoiding building my own
gcc crosstool prior to starting building LLVM and LLVM-GCC.  LLVM builds
just fine, it's building llvm-gcc that gives me this error:

gcc -c -g -O2 -DIN_GCC -DCROSS_DIRECTORY_STRUCTURE -W -Wall -Wwrite-strings
-Wstrict-prototypes -Wmissing-prototypes -DHAVE_CONFIG_H -DGENERATOR_FILE
-I. -Ibuild -I../../../../src/llvm-gcc4.2-2.5.source/gcc
-I../../../../src/llvm-gcc4.2-2.5.source/gcc/build
-I../../../../src/llvm-gcc4.2-2.5.source/gcc/../include
-I../../../../src/llvm-gcc4.2-2.5.source/gcc/../libcpp/include
-I../../../../src/llvm-gcc4.2-2.5.source/gcc/../libdecnumber
-I../libdecnumber -I/tmp/llvm-project/install/x86_64-arm/llvm/include
-I/tmp/llvm-project/src/llvm-2.5/include -DENABLE_LLVM
-I/tmp/llvm-project/install/x86_64-arm/llvm/include  -D_DEBUG  -D_GNU_SOURCE
-D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS   -o build/gencondmd.o
build/gencondmd.c

../../../../src/llvm-gcc4.2-2.5.source/gcc/config/arm/arm.md:4788: error:
‘MACHO_DYNAMIC_NO_PIC_P’ undeclared here (not in a function)

This tells me there are some Darwin-specific bits in arm.md which shouldn't
be there (MachO is Mac OS X-specific).  I'm using the attached script
llvm-arm-crosstool.sh to configure/build/install LLVM and LLVM-GCC from the
2.5 release.  If anyone wants to try it out and see if it works for them,
I'd love to hear their experiences.

If any ARM/GCC experts know how to fix arm.md to not refer to
Darwin-specific macros, that would be great, too.

Building llvm-gcc was relatively painless. The only problem
I've
> encountered was that my target had no hardware floating point support
> and the endianess for the softfloat implementation (libgcc) differed
> from integer endianess, which required some patches at the llvm side.
> I have not checked if this is still necessary. If you run into the
> same problems, I would be happy to share the patch (which I have
> updated to llvm 2.4 at some point).

I would be interested in seeing your patch, if you wouldn't mind sharing
it.  Bonus points if you have a script similar to mine above to simplify the
entire process, or your notes/directions that I can convert into an
easy-to-run script.  :-)

Thanks,
Misha
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On Mar 12, 2009, at 8:30 AMPDT, Misha Brukman wrote:
>
> ../../../../src/llvm-gcc4.2-2.5.source/gcc/config/arm/arm.md:4788:  
> error: ‘MACHO_DYNAMIC_NO_PIC_P’ undeclared here (not in a function)
>
> This tells me there are some Darwin-specific bits in arm.md which  
> shouldn't be there (MachO is Mac OS X-specific).  I'm using the  
> attached script llvm-arm-crosstool.sh to configure/build/install  
> LLVM and LLVM-GCC from the 2.5 release.  If anyone wants to try it  
> out and see if it works for them, I'd love to hear their experiences.
>
> If any ARM/GCC experts know how to fix arm.md to not refer to Darwin- 
> specific macros, that would be great, too.
Probably the right general idea is to #define MACHO_DYNAMIC_NO_PIC_P  
to be 0 for non-Darwin targets.  Not sure where to put this so it will  
work for both targets (the Darwin definition comes from config/ 
darwin.h).

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We absolutely need someone to drive this. Some of us who work on the  
ARM target are developing and testing our work on proprietary  
platforms. We can't share our infrastructure with the public. It would  
be nice if someone can figure out the following and document them:

1. How to build llvm-gcc with ARM for various platforms?
2. How to use llvm-gcc to run llvm test suite on qemu, or some other  
ARM based netbooks.
3. Anything else of interest. :-)

Would someone step up and drive this please?

Thanks,

Evan

On Mar 12, 2009, at 8:30 AM, Misha Brukman wrote:
> On Thu, Mar 12, 2009 at 6:17 AM, Dietmar Ebner <ebner at
complang.tuwien.ac.at
> > wrote:
> On Mar 11, 2009, at 9:44 PM, Misha Brukman wrote:
> > The problem I've had is building an LLVM cross-compiler from
Linux/
> > x86 to Linux/ARM (as has another llvm-dev poster).  Someone
> > mentioned to me off-list that he managed to get it to build, but I
> > haven't been able to reproduce the build using his instructions
> > (I'll post my results in another thread).
>
> I've been successfully experimenting with an arm-softfloat-linux-gnu
> cross-compiler at the time of llvm 2.1. The easiest way to get this
> working is to use Dan Kegel's crosstool to build a regular gcc
> toolchain. This will give you binutils, libgcc, and glibc, which you
> will need anyway.
>
> I've been trying to build for the target arm-none-linux-gnueabi,  
> using the appropriate pre-built CodeSourcery toolchain, hence  
> avoiding building my own gcc crosstool prior to starting building  
> LLVM and LLVM-GCC.  LLVM builds just fine, it's building llvm-gcc  
> that gives me this error:
>
> gcc -c -g -O2 -DIN_GCC -DCROSS_DIRECTORY_STRUCTURE -W -Wall -Wwrite- 
> strings -Wstrict-prototypes -Wmissing-prototypes -DHAVE_CONFIG_H - 
> DGENERATOR_FILE -I. -Ibuild -I../../../../src/llvm-gcc4.2-2.5.source/ 
> gcc -I../../../../src/llvm-gcc4.2-2.5.source/gcc/build -I../../../../ 
> src/llvm-gcc4.2-2.5.source/gcc/../include -I../../../../src/llvm- 
> gcc4.2-2.5.source/gcc/../libcpp/include  -I../../../../src/llvm- 
> gcc4.2-2.5.source/gcc/../libdecnumber -I../libdecnumber -I/tmp/llvm- 
> project/install/x86_64-arm/llvm/include -I/tmp/llvm-project/src/ 
> llvm-2.5/include -DENABLE_LLVM -I/tmp/llvm-project/install/x86_64- 
> arm/llvm/include  -D_DEBUG  -D_GNU_SOURCE -D__STDC_LIMIT_MACROS - 
> D__STDC_CONSTANT_MACROS   -o build/gencondmd.o build/gencondmd.c
>
> ../../../../src/llvm-gcc4.2-2.5.source/gcc/config/arm/arm.md:4788:  
> error: ‘MACHO_DYNAMIC_NO_PIC_P’ undeclared here (not in a function)
>
> This tells me there are some Darwin-specific bits in arm.md which  
> shouldn't be there (MachO is Mac OS X-specific).  I'm using the  
> attached script llvm-arm-crosstool.sh to configure/build/install  
> LLVM and LLVM-GCC from the 2.5 release.  If anyone wants to try it  
> out and see if it works for them, I'd love to hear their experiences.
>
> If any ARM/GCC experts know how to fix arm.md to not refer to Darwin- 
> specific macros, that would be great, too.
>
> Building llvm-gcc was relatively painless. The only problem I've
> encountered was that my target had no hardware floating point support
> and the endianess for the softfloat implementation (libgcc) differed
> from integer endianess, which required some patches at the llvm side.
> I have not checked if this is still necessary. If you run into the
> same problems, I would be happy to share the patch (which I have
> updated to llvm 2.4 at some point).
>
> I would be interested in seeing your patch, if you wouldn't mind  
> sharing it.  Bonus points if you have a script similar to mine above  
> to simplify the entire process, or your notes/directions that I can  
> convert into an easy-to-run script.  :-)
>
> Thanks,
> Misha
>
<llvm-arm-crosstool.sh>_______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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Attached is the patch I've been building arm-eabi with, which might
help with linux-gnueabi. I disable multilib to get around several bugs
with thumb. I build cross binutils first, then llvm, then llvm-gcc
with newlib merged in.

The following bugs need to be addressed for these non-Darwin ARM targets:
1388
2313
2545
2985

deep

On Fri, Mar 13, 2009 at 12:30 AM, Misha Brukman <brukman at gmail.com>
wrote:
> On Thu, Mar 12, 2009 at 6:17 AM, Dietmar Ebner <ebner at
complang.tuwien.ac.at>
> wrote:
>>
>> On Mar 11, 2009, at 9:44 PM, Misha Brukman wrote:
>> > The problem I've had is building an LLVM cross-compiler from
Linux/
>> > x86 to Linux/ARM (as has another llvm-dev poster).  Someone
>> > mentioned to me off-list that he managed to get it to build, but I
>> > haven't been able to reproduce the build using his
instructions
>> > (I'll post my results in another thread).
>>
>> I've been successfully experimenting with an
arm-softfloat-linux-gnu
>> cross-compiler at the time of llvm 2.1. The easiest way to get this
>> working is to use Dan Kegel's crosstool to build a regular gcc
>> toolchain. This will give you binutils, libgcc, and glibc, which you
>> will need anyway.
>
> I've been trying to build for the target arm-none-linux-gnueabi, using
the
> appropriate pre-built CodeSourcery toolchain, hence avoiding building my
own
> gcc crosstool prior to starting building LLVM and LLVM-GCC.  LLVM builds
> just fine, it's building llvm-gcc that gives me this error:
>
> gcc -c -g -O2 -DIN_GCC -DCROSS_DIRECTORY_STRUCTURE -W -Wall -Wwrite-strings
> -Wstrict-prototypes -Wmissing-prototypes -DHAVE_CONFIG_H -DGENERATOR_FILE
> -I. -Ibuild -I../../../../src/llvm-gcc4.2-2.5.source/gcc
> -I../../../../src/llvm-gcc4.2-2.5.source/gcc/build
> -I../../../../src/llvm-gcc4.2-2.5.source/gcc/../include
> -I../../../../src/llvm-gcc4.2-2.5.source/gcc/../libcpp/include
> -I../../../../src/llvm-gcc4.2-2.5.source/gcc/../libdecnumber
> -I../libdecnumber -I/tmp/llvm-project/install/x86_64-arm/llvm/include
> -I/tmp/llvm-project/src/llvm-2.5/include -DENABLE_LLVM
> -I/tmp/llvm-project/install/x86_64-arm/llvm/include  -D_DEBUG 
-D_GNU_SOURCE
> -D__STDC_LIMIT_MACROS -D__STDC_CONSTANT_MACROS   -o build/gencondmd.o
> build/gencondmd.c
>
> ../../../../src/llvm-gcc4.2-2.5.source/gcc/config/arm/arm.md:4788: error:
> ‘MACHO_DYNAMIC_NO_PIC_P’ undeclared here (not in a function)
>
> This tells me there are some Darwin-specific bits in arm.md which
shouldn't
> be there (MachO is Mac OS X-specific).  I'm using the attached script
> llvm-arm-crosstool.sh to configure/build/install LLVM and LLVM-GCC from the
> 2.5 release.  If anyone wants to try it out and see if it works for them,
> I'd love to hear their experiences.
>
> If any ARM/GCC experts know how to fix arm.md to not refer to
> Darwin-specific macros, that would be great, too.
>
>> Building llvm-gcc was relatively painless. The only problem I've
>> encountered was that my target had no hardware floating point support
>> and the endianess for the softfloat implementation (libgcc) differed
>> from integer endianess, which required some patches at the llvm side.
>> I have not checked if this is still necessary. If you run into the
>> same problems, I would be happy to share the patch (which I have
>> updated to llvm 2.4 at some point).
>
> I would be interested in seeing your patch, if you wouldn't mind
sharing
> it.  Bonus points if you have a script similar to mine above to simplify
the
> entire process, or your notes/directions that I can convert into an
> easy-to-run script.  :-)
>
> Thanks,
> Misha
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
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On Mar 12, 2009, at 4:30 PM, Misha Brukman wrote:
> I've been trying to build for the target arm-none-linux-gnueabi,  
> using the appropriate pre-built CodeSourcery toolchain, hence  
> avoiding building my own gcc crosstool prior to starting building  
> LLVM and LLVM-GCC.  LLVM builds just fine, it's building llvm-gcc  
> that gives me this error:
> [...]
> ../../../../src/llvm-gcc4.2-2.5.source/gcc/config/arm/arm.md:4788:  
> error: ‘MACHO_DYNAMIC_NO_PIC_P’ undeclared here (not in a function)
I think this error is a result of the switch to Appel's gcc 4.2. I  
cannot say if it's hard to fix these issues (I guess not), but if you  
need a quick solution, you might sill use the 4.0 based frontend. As  
far as I know, the bitcode format should be compatible to the current  
tools (somebody please correct me if I'm wrong).
> Building llvm-gcc was relatively painless. The only problem I've
> encountered was that my target had no hardware floating point support
> and the endianess for the softfloat implementation (libgcc) differed
> from integer endianess, which required some patches at the llvm side.
> I have not checked if this is still necessary. If you run into the
> same problems, I would be happy to share the patch (which I have
> updated to llvm 2.4 at some point).
>
> I would be interested in seeing your patch, if you wouldn't mind  
> sharing it.  Bonus points if you have a script similar to mine above  
> to simplify the entire process, or your notes/directions that I can  
> convert into an easy-to-run script.  :-)
Sorry, there's no such script. But here's how I configured llvm-gcc:
configure --prefix=<wherever> --program-prefix=llvm-arm- --enable- 
llvm=<path to llvm> --enable-checking --target=arm-softfloat-linux-gnu  
--disable-shared --disable-nls --disable-threads --with-float=soft -- 
enable-languages=c

You can find a tiny patch for llvm-gcc and the necessary changes for  
llvm 2.4 attached. The llvm patch should cleanly apply to llvm 2.4,  
but I had to pick the changes from a private repository with some  
modifications. Thus, the patch is untested and I cannot guarantee if I  
got all the necessary bits. Feel free to contact me if you run into  
troubles.

The patch allows to have different endianess for integer and floating  
point types. I'm not sure if this is the best way to handle this  
issue, but at least it seems to be working (I've used it to cross- 
compile SPECINT 2000). Note that you probably won't need all this if  
you have a hardware FPU.

Best,

-
Dietmar

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---------------------------------------------------------------------
Dietmar Ebner
CD Laboratory - Compilation Techniques for Embedded Processors
Institut fuer Computersprachen  E: ebner at complang.tuwien.ac.at
Technische Universitaet Wien    T: (+431) 58801-58521
Argentinierstrasse 8 / E1851    F: (+431) 58801-18598
1040 Wien, Austria              W: www.complang.tuwien.ac.at/cd/ebner