[OpenMP] Make OpenMP generated code for the NVIDIA device relocatable by default

[gtbercea]

Summary

When device offloading is enabled and the device is an NVIDIA GPU, OpenMP target regions must be compiled with relocation enabled by passing the "-c" flag to the PTXAS invocation.

[gtbercea]

Update patch to reflect latest source code changes.

[Hahnfeld]

test/Driver/openmp-offload.c

598

This path might not be correct on all systems. Do we really need this check?

[gtbercea]

Remove redundant check.

[gtbercea]

Change prefix name in test.

[Hahnfeld]

LGTM after fixing the check-prefix

test/Driver/openmp-offload.c

595

CHK-PTXAS-DEFAULT

[gtbercea]

Fix prefix.

lib/Driver/ToolChains/Cuda.cpp

void NVPTX::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
   CmdArgs.push_back("--output-file");
   CmdArgs.push_back(Args.MakeArgString(Output.getFilename()));
   for (const auto& II : Inputs)
     CmdArgs.push_back(Args.MakeArgString(II.getFilename()));
 
   for (const auto& A : Args.getAllArgValues(options::OPT_Xcuda_ptxas))
     CmdArgs.push_back(Args.MakeArgString(A));
 
+  // In OpenMP we need to generate relocatable code.
+  if (JA.isOffloading(Action::OFK_OpenMP))
+    CmdArgs.push_back("-c");
+
   const char *Exec;
   if (Arg *A = Args.getLastArg(options::OPT_ptxas_path_EQ))
     Exec = A->getValue();
   else
     Exec = Args.MakeArgString(TC.GetProgramPath("ptxas"));
   C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
 }
 

test/Driver/openmp-offload.c

 // CHK-UBUJOBS: clang-offload-bundler{{.*}}" "-type=o" "-targets=openmp-powerpc64le-ibm-linux-gnu,openmp-x86_64-pc-linux-gnu,host-powerpc64le--linux" "-outputs=
 // CHK-UBUJOBS-SAME: [[RES:[^\\/]+\.o]]" "-inputs={{.*}}[[T1OBJ]],{{.*}}[[T2OBJ]],{{.*}}[[HOSTOBJ]]"
 // CHK-UBUJOBS-ST: clang{{.*}}" "-cc1" "-triple" "powerpc64le--linux" "-S" {{.*}}"-fopenmp" {{.*}}"-o" "
 // CHK-UBUJOBS-ST-SAME: [[HOSTASM:[^\\/]+\.s]]" "-x" "ir" "{{.*}}[[HOSTBC]]"
 // CHK-UBUJOBS-ST: clang{{.*}}" "-cc1as" "-triple" "powerpc64le--linux" "-filetype" "obj" {{.*}}"-o" "
 // CHK-UBUJOBS-ST-SAME: [[HOSTOBJ:[^\\/]+\.o]]" "{{.*}}[[HOSTASM]]"
 // CHK-UBUJOBS-ST: clang-offload-bundler{{.*}}" "-type=o" "-targets=openmp-powerpc64le-ibm-linux-gnu,openmp-x86_64-pc-linux-gnu,host-powerpc64le--linux" "-outputs=
 // CHK-UBUJOBS-ST-SAME: [[RES:[^\\/]+\.o]]" "-inputs={{.*}}[[T1OBJ]],{{.*}}[[T2OBJ]],{{.*}}[[HOSTOBJ]]"
+
+/// ###########################################################################
+
+/// Check PTXAS is passed -c flag when offloading to an NVIDIA device using OpenMP.
+// RUN:   %clang -### -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda -save-temps -no-canonical-prefixes %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHK-PTXAS-DEFAULT %s
+
+// CHK-PTXAS-DEFAULT: ptxas{{.*}}" "-c"