[R-pkg-devel] Creating a Makevars that includes objects from another compiler

[Charles Determan]

I ultimately found more details in the 'Writing R Extensions' in another
section (http://www.hep.by/gnu/r-patched/r-exts/R-exts_11.html).  I needed
to assign the object files to the OBJECTS variable with an '=' sign and
remove anything below the .so block.  The new block that successfully
compiled looked like this:

OBJECTS = $(cu_sharedlibs) $(cpp_sharedlibs)
...
gpuRcuda.so: $(OBJECTS)

By using OBJECTS instead of OBJS it overwrote R's default assignment of
object files to link.

Cheers,
Charles

On Fri, Jun 5, 2015 at 11:13 AM, Neal Fultz <nfultz at gmail.com> wrote:

> Weird. Maybe it's not using that target at all, and is instead using a
> generic .so target?
>
> On Fri, Jun 5, 2015 at 9:02 AM, Charles Determan <cdetermanjr at gmail.com>
> wrote:
>
>> A quick followup, even when I try and use the g++ I cannot seem to pass
>> the
>> objects (it keeps omitting the .o file generated from nvcc).  How can I
>> have my Makevars file pass a defined list of object files to the final
>> shared library call?
>>
>> Alternate  gpuRcuda.so block where the build output still doesn't use the
>> OBJS variable (note, I confirmed that the OBJS variable does contain all
>> .o
>> files)
>>
>> gpuRcuda.so: $(OBJS)
>>         $(CXX) $< -o $@ $(R_LIBS) $(LIBS)
>>
>> Regards,
>> Charles
>>
>> On Fri, Jun 5, 2015 at 9:42 AM, Charles Determan <cdetermanjr at gmail.com>
>> wrote:
>>
>> > Greetings,
>> >
>> > Quick context, I have been working on developing a set of packages to
>> make
>> > GPU computing as simple as possible with R.  I have a functional package
>> > that works very nicely with OpenCL based code (gpuR -
>> > https://github.com/cdeterman/gpuR) but I also am building a companion
>> > CUDA backend package (gpuRcuda - https://github.com/cdeterman/gpuRcuda)
>> > which is stripped down to a single function at the moment to work out
>> the
>> > compiling issue described below.
>> >
>> > The problem is, CUDA requires me to use the NVCC compiler.  So I cannot
>> > just rely on the magic of Rcpp, I need to create a Makevars file.  I
>> have
>> > done so and I am very close but I cannot get the shared object file to
>> be
>> > created with NVCC.  The individual files compile with NVCC just fine,
>> the
>> > build script just keeps switching back to g++ for the shared object
>> file.
>> >
>> > A quick excerpt from my build script
>> >
>> > '''
>> > /usr/local/cuda-7.0/bin/nvcc -arch=sm_30 -Xcompiler -fPIC -Xcudafe
>> > --diag_suppress=boolean_controlling_expr_is_constant
>> -I/usr/share/R/include
>> > -I/usr/include
>> > -I/home/cdeterman/R/x86_64-pc-linux-gnu-library/3.2/RViennaCL/include
>> > -I"/home/cdeterman/R/x86_64-pc-linux-gnu-library/3.2/RcppEigen/include"
>> > viennacl_sgemm.cu -c
>> >
>> > # NOW IT SWITCHES TO G++?
>> >
>> > ccache g++-4.8 -shared -L/usr/lib/R/lib -Wl,-Bsymbolic-functions
>> > -Wl,-z,relro -o gpuRcuda.so RcppExports.o viennacl_cudaMatrix_sgemm.o
>> > -L/usr/lib/R/lib -lR
>> > '''
>> >
>> > You can see my current Makevars file here (
>> > https://github.com/cdeterman/gpuRcuda/blob/master/src/Makevars).
>> >
>> > I have read in the 'Writing R Extensions' manual that this is possible
>> > with the OBJECTS macro (
>> >
>> http://cran.r-project.org/doc/manuals/r-release/R-exts.html#Creating-shared-objects
>> )
>> > however I cannot figure out how to use it properly (and haven't been
>> able
>> > to find an example).  I have looked at the other packages on CRAN that
>> also
>> > use CUDA (such as WideLM which I tried to emulate) but I can't seem to
>> > figure out why R keeps defaulting the shared library creation to g++.
>> > Perhaps my shared object section of my Makevars is incorrect?
>> >
>> > Any insights would be sincerely appreciated,
>> > Charles
>> >
>> >
>>
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>>
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>
>

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