[OpenMP] Enable on device linking with NVLINK to ignore dynamic libraries

[gtbercea]

Summary

NVLINK does not support dynamic linking so passing dynamic libraries to NVLINK should be avoided.

This patch fixes a bug whereby an explicit passing of the dynamic library via it's full path will result in it being treated like an input.

[ABataev]

lib/Driver/ToolChains/Cuda.cpp

707

I would suggest to use types::lookupTypeForExtension function and compare the result with the types::TY_Object.

[gtbercea]

lib/Driver/ToolChains/Cuda.cpp

707

Isn't that too broad? I only want .so files.

[ABataev]

lib/Driver/ToolChains/Cuda.cpp

707

I don't think nvlink supports anything else except for objects. Also, in future, we could extend it if it is required.

[gtbercea]

lib/Driver/ToolChains/Cuda.cpp

707

But won't this exclude .o files too? I don't want to ignore those.

[ABataev]

lib/Driver/ToolChains/Cuda.cpp

707

This function returns TY_Object for .o and .obj extensions (on Windows)

[gtbercea]

lib/Driver/ToolChains/Cuda.cpp

707

Oh now I think I understand what you mean. You mean ignore everything that's not a TY_Object? That doesn't work here because I am looking at the original input file name.

[ABataev]

lib/Driver/ToolChains/Cuda.cpp

707

Yes, but you can use types::lookupTypeForExtension function to classify the original input file name.

[gtbercea]

For now this patch doesn't make sense until the main linking patch lands but it's a case we need to keep in mind.

lib/Driver/ToolChains/Cuda.cpp

for (const auto &II : Inputs) {
     }
 
     StringRef OrigInputFileName =
         llvm::sys::path::filename(II.getBaseInput());
     if (OrigInputFileName.endswith(".a")) {
       const char *StaticLibName =
           C.getArgs().MakeArgString(II.getFilename());
       CmdArgs.push_back(StaticLibName);
+    } else if (OrigInputFileName.endswith(".so")) {
+      // Only static libraries are supported.
+      // Dynamic libraries are ignored.
+      continue;
     } else {
       // If the original input is not an object file then it means the
       // assembly step has actually produced a cubin so we need to
       // rename it accordingly.
       if ((!C.canSkipOffloadBundler() && OrigInputFileName.endswith(".o")) ||
           (C.canSkipOffloadBundler() && !OrigInputFileName.endswith(".o"))) {
         // Create cubin file name and add it as a temporary file.
         SmallString<256> Filename(II.getFilename());

test/Driver/openmp-offload-gpu.c

 // RUN:   %clang -### -no-canonical-prefixes -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -Xopenmp-target -march=sm_60 %s -fopenmp-cuda-force-full-runtime -fno-openmp-cuda-force-full-runtime 2>&1 \
 // RUN:   | FileCheck -check-prefix=NO_FULL_RUNTIME %s
 // NO_FULL_RUNTIME-NOT: "-{{fno-|f}}openmp-cuda-force-full-runtime"
 
 // RUN:   %clang -### -no-canonical-prefixes -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -Xopenmp-target -march=sm_60 %s -fopenmp-cuda-teams-reduction-recs-num=2048 2>&1 \
 // RUN:   | FileCheck -check-prefix=CUDA_RED_RECS %s
 // CUDA_RED_RECS: clang{{.*}}"-cc1"{{.*}}"-triple" "nvptx64-nvidia-cuda"
 // CUDA_RED_RECS-SAME: "-fopenmp-cuda-teams-reduction-recs-num=2048"
+
+/// ###########################################################################
+
+/// Check NVLINK ignores dynamic libraries.
+// RUN:   touch %t-dynlib.so
+// RUN:   %clang -### -no-canonical-prefixes -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda %t-dynlib.so %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-NVLINK-IGNORE-DYNLIB %s
+
+// CHK-NVLINK-IGNORE-DYNLIB-NOT: nvlink{{.*}}dynlib