error: Linking globals named 'memcpy': symbol multiply defined!

[gnzlbg]

I am getting that linker error when trying to use the coresimd library from a cuda kernel :/

Compiling host v0.1.0 (/stdsimd/crates/nvptx-test)                                                                                                                                          
error: failed to run custom build command for `host v0.1.0 (/Users/gnzlbg/projects/sideprojects/stdsimd/crates/nvptx-test)`                                                                                                       
process didn't exit successfully: `/stdsimd/crates/nvptx-test/target/debug/build/host-5b9ca8737382a47e/build-script-build` (exit code: 1)
--- stderr
[PTX] Unable to build a PTX crate!
[PTX]    Compiling kernel v0.1.0 (/stdsimd/crates/nvptx-test/kernel)
[PTX]    Compiling proxy v0.0.0 (/private/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/ptx-builder-0.5/kernel/c4e147d83c46a030)
[PTX] error: linking with `ptx-linker` failed: exit code: 1
[PTX]   |
[PTX]   = note: "ptx-linker" "-L" "/Users/gnzlbg/.xargo/lib/rustlib/nvptx64-nvidia-cuda/lib" "/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/ptx-builder-0.5/kernel/c4e147d83c46a030/target/nvptx64-nvidia-cuda/release/deps/proxy.proxy.43qsgff7-cgu.0.rcgu.o" "-o" "/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/ptx-builder-0.5/kernel/c4e147d83c46a030/target/nvptx64-nvidia-cuda/release/deps/proxy.ptx" "/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/ptx-builder-0.5/kernel/c4e147d83c46a030/target/nvptx64-nvidia-cuda/release/deps/proxy.37oceufmlocs4b5j.rcgu.o" "-O1" "-L" "/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/ptx-builder-0.5/kernel/c4e147d83c46a030/target/nvptx64-nvidia-cuda/release/deps" "-L" "/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/ptx-builder-0.5/kernel/c4e147d83c46a030/target/release/deps" "-L" "/Users/gnzlbg/.xargo/lib/rustlib/nvptx64-nvidia-cuda/lib" "--start-group" "-Bstatic" "--whole-archive" "/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/rustcNH6EGz/libkernel-ad470a324c1962cc.rlib" "--no-whole-archive" "--whole-archive" "/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/rustcNH6EGz/libcoresimd-9761acf5e343c1f3.rlib" "--no-whole-archive" "--whole-archive" "/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/rustcNH6EGz/libcore-58de11be20fe5a04.rlib" "--no-whole-archive" "--end-group" "/var/folders/mm/y444qqwd0kn52fycyz6nsph40000gn/T/rustcNH6EGz/libcompiler_builtins-20af736248a5f37a.rlib" "-shared" "-Bdynamic"
[PTX]   = note:  [INFO] Going to link 2 bitcode modules and 4 rlibs...
[PTX]                   
[PTX]           error: Linking globals named 'memcpy': symbol multiply defined!
[PTX]           
[PTX] 
[PTX] error: aborting due to previous error
[PTX] 
[PTX] error: Could not compile `proxy`.
[PTX] 
[PTX] To learn more, run the command again with --verbose.

to reproduce the issue:

git clone https://github.com/gnzlbg/stdsimd
cd stdsimd
git checkout nvptx_ci
cd crates/nvptx-test
cargo build

[gnzlbg]

any ideas ?

[denzp]

The error message is coming directly from LLVM... And it definitely has something to do about kernel function name.

I suppose we are getting the symbol first from compiler-builtins and the second time from the kernel crate.

Technically we can try to toggle some features of the compiler-builtins crate (enabling mangled-names or disabling mem that is set by xargo) but I'm not sure whether it will have consequences on dependent crates.

[gnzlbg]

Indeed, renaming the symbol from memcpy to something else solves the issue. I'm trying to get CI running for the NVPTX intrinsics of core::arch and it isn't as trivial as I expected.

[denzp]

Yes, that can be :) Some time ago, I tried to find CI platform that has CUDA compatible hardware, but didn't have a luck. The best we can do right now is to test build process and verify output PTX assembly.

[gnzlbg]

I'm closing this, since renaming the function to something else solved the issue.