[LLVMdev] undefined reference to 'llvm_gcda_start_file', 'llvm_gcda_emit_arcs', etc
samsonov at google.com
Thu Mar 14 23:51:03 PDT 2013
On Fri, Mar 15, 2013 at 1:36 AM, Qun Fa <testforqunfa at gmail.com> wrote:
> Hi All,
> I think Nick's suggestion is correct, my code was linked against
> libprofile_rt.a, which had gcda profiling code before, but was removed
> So, I couldn't find the correct symbols from libprofile_rt.a any more.
> Now my assumption is I need to use the correct library that is provided by
> compiler-rt. May I know which one?
> I am building the entire llvm/clang including compiler-rt based on the
> instructions given on the clang get started page (
> http://clang.llvm.org/get_started.html), but with CMake instead of
> Makefile. But I also noticed in the compiler-rt/lib/CMakeLists.txt file, we
> have the following FIXME.
> # FIXME: Add support for the profile library.
> So, if I want to use the correct library, do I have to switch to Makefile?
> Any ideas?
Yeah, can you try Makefile (I think it should build libprofile_rt from
GCDAProfiling.c that you need). I'll see if I can add CMake support for
profile in compiler-rt any time soon.
However, looks like Clang driver won't be smart enough to link two archives
(lib/libprofile_rt.a and the one under lib/clang/3.3/linux/...), so we may
need to patch the driver as well.
> Thanks very much,
> On Thu, Mar 14, 2013 at 8:46 AM, Qun Fa <testforqunfa at gmail.com> wrote:
>> Thanks for your reply.
>> May I know which is the recommended library that should be linked against?
>> I am currently linking libprofile_rt.a.
>> And I have noticed the differences that, if we do
>> `nm libprofile_rt.a | grep llvm`
>> with my old copy of the llvm/clang installation, I can see
>> 00000000000005e0 T _llvm_gcda_emit_arcs
>> 0000000000000b48 S _llvm_gcda_emit_arcs.eh
>> 0000000000000430 T _llvm_gcda_emit_function
>> 0000000000000aa8 S _llvm_gcda_emit_function.eh
>> 00000000000006c0 T _llvm_gcda_end_file
>> 0000000000000b98 S _llvm_gcda_end_file.eh
>> 00000000000003d0 T _llvm_gcda_increment_indirect_counter
>> 0000000000000a80 S _llvm_gcda_increment_indirect_counter.eh
>> 0000000000000000 T _llvm_gcda_start_file
>> 0000000000000a08 S _llvm_gcda_start_file.eh
>> They are the symbols that my test build is looking for.
>> But with the latest codebase, here is what I saw
>> 00000000000000a8 T llvm_start_basic_block_tracing
>> 0000000000000067 T llvm_trace_basic_block
>> 0000000000000467 T llvm_decrement_path_count
>> 000000000000042a T llvm_increment_path_count
>> 0000000000000662 T llvm_start_path_profiling
>> 0000000000000020 T llvm_start_edge_profiling
>> 0000000000000020 T llvm_start_opt_edge_profiling
>> Thanks again,
>> On Thu, Mar 14, 2013 at 1:11 AM, Nick Lewycky <nicholas at mxc.ca> wrote:
>>> Qun Fa wrote:
>>>> I am trying to test my project and get the code coverage with a version
>>>> of clang compiler that was built from the latest llvm/clang codebase.
>>>> It worked for a while. But today, after I updated my local checkout, and
>>>> re-build llvm, clang and compiler-rt, when I test my project again, I
>>>> got the errors with undefined reference to 'llvm_gcda_start_file',
>>>> 'llvm_gcda_emit_arcs', 'llvm_gcda_emit_function', and
>>>> I have searched the codebase, and have found the functions are defined
>>>> in GCDAProfiling.c file, but not sure why this suddenly doesn't work
>>>> for me.
>>>> Anyone can give any suggestions?
>>> Those symbols should be provided by compiler-rt/lib/profile/**GCDAProfiling.c.
>>> There used to be a copy in llvm's tree, but I deleted that one recently.
>>> It's possible you used to be using the one from llvm, but now need to
>>> switch to using the one from compiler-rt?
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> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu
Alexey Samsonov, MSK
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