if this can help:

llvm::Linker::SrcM is NULL

(gdb) where
#0  _M_data (this=0x90) at /usr/include/c++/4.8.0/bits/basic_string.h:293
#1  _M_rep (this=0x90) at /usr/include/c++/4.8.0/bits/basic_string.h:301
#2  size (this=0x90) at /usr/include/c++/4.8.0/bits/basic_string.h:716
#3  empty (this=0x90) at /usr/include/c++/4.8.0/bits/basic_string.h:812
#4  run (this=0x7fffe1bd7e30) at LinkModules.cpp:1152
#5  llvm::Linker::linkInModule (this=this@entry=0x7fffe1bd8190,
Src=Src@entry=0x0, Mode=Mode@entry=0, 
    ErrorMsg=ErrorMsg@entry=0x7fffe1bd83c0) at LinkModules.cpp:1302
#6  0x00007f74fe1870ef in llvm::Linker::LinkModules (Dest=<optimized out>,
Src=0x0, Mode=0, 
    ErrorMsg=0x7fffe1bd83c0) at LinkModules.cpp:1322
#7  0x00007f74ff96eecc in clover::compile_program_llvm(clover::compat::string
const&, pipe_shader_ir, clover::compat::string const&, clover::compat::string
const&) () from /usr/lib/libOpenCL.so
#8  0x00007f74ff951b19 in _cl_program::build(std::vector<_cl_device_id*,
std::allocator<_cl_device_id*> > const&, char const*) () from
/usr/lib/libOpenCL.so
#9  0x00007f74ff962a70 in clBuildProgram () from /usr/lib/libOpenCL.so
#10 0x000000000043ac60 in ?? ()
#11 0x0000000000436d1d in ?? ()
#12 0x0000000000406af3 in ?? ()
#13 0x00007f7501405a15 in __libc_start_main () from /usr/lib/libc.so.6
#14 0x0000000000408175 in ?? ()
(gdb) up
#4  run (this=0x7fffe1bd7e30) at LinkModules.cpp:1152
1152      if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty()
&&
(gdb) p *this
$3 = {DstM = 0x23c7030, SrcM = 0x0, TypeMap = {<llvm::ValueMapTypeRemapper> = {
      _vptr.ValueMapTypeRemapper = 0x7f74fec64810 <vtable for (anonymous
namespace)::TypeMapTy+16>}, 
    MappedTypes = {<llvm::DenseMapBase<llvm::DenseMap<llvm::Type*, llvm::Type*,
llvm::DenseMapInfo<llvm::Type*> >, llvm::Type*, llvm::Type*,
llvm::DenseMapInfo<llvm::Type*> >> = {<No data fields>}, Buckets = 0x0, 
      NumEntries = 0, NumTombstones = 0, NumBuckets = 0}, 
    SpeculativeTypes = {<llvm::SmallVectorImpl<llvm::Type*>> =
{<llvm::SmallVectorTemplateBase<llvm::Type*, true>> =
{<llvm::SmallVectorTemplateCommon<llvm::Type*, void>> =
{<llvm::SmallVectorBase> = {
              BeginX = 0x7fffe1bd7e78, EndX = 0x7fffe1bd7e78, CapacityX =
0x7fffe1bd7ef8}, 
            FirstEl = {<llvm::AlignedCharArray<8ul, 8ul>> = {
                buffer = "P\346\061\002\000\000\000"}, <No data fields>}}, <No
data fields>}, <No data fields>}, Storage = {InlineElts =
{{<llvm::AlignedCharArray<8ul, 8ul>> = {
              buffer = "\001\000\000\000\000\000\000"}, <No data fields>},