[OpenMP] Improve search for libomptarget-nvptx

When looking for the bclib Clang considered the default library
path first while it preferred directories in LIBRARY_PATH when
constructing the invocation of nvlink. The latter actually makes
more sense because during development it allows using a non-default
runtime library. So change the search for the bclib to start
looking in directories given by LIBRARY_PATH.
Additionally add a new option --libomptarget-nvptx-path= which
will be searched first. This will be handy for testing purposes.

Differential Revision: https://reviews.llvm.org/D51686

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@343230 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 6 deletions

diff --git a/lib/Driver/ToolChains/Cuda.cpp b/lib/Driver/ToolChains/Cuda.cpp
index a446c4d9d4..08e49fa6a5 100644
--- a/lib/Driver/ToolChains/Cuda.cpp
+++ b/lib/Driver/ToolChains/Cuda.cpp
@@ -511,6 +511,11 @@ void NVPTX::OpenMPLinker::ConstructJob(Compilation &C, const JobAction &JA,
   CmdArgs.push_back("-arch");
   CmdArgs.push_back(Args.MakeArgString(GPUArch));
 
+  // Assume that the directory specified with --libomptarget_nvptx_path
+  // contains the static library libomptarget-nvptx.a.
+  if (const Arg *A = Args.getLastArg(options::OPT_libomptarget_nvptx_path_EQ))
+    CmdArgs.push_back(Args.MakeArgString(Twine("-L") + A->getValue()));
+
   // Add paths specified in LIBRARY_PATH environment variable as -L options.
   addDirectoryList(Args, CmdArgs, "-L", "LIBRARY_PATH");
 
@@ -647,12 +652,9 @@ void CudaToolChain::addClangTargetOptions(
 
   if (DeviceOffloadingKind == Action::OFK_OpenMP) {
     SmallVector<StringRef, 8> LibraryPaths;
-    // Add path to lib and/or lib64 folders.
-    SmallString<256> DefaultLibPath =
-      llvm::sys::path::parent_path(getDriver().Dir);
-    llvm::sys::path::append(DefaultLibPath,
-        Twine("lib") + CLANG_LIBDIR_SUFFIX);
-    LibraryPaths.emplace_back(DefaultLibPath.c_str());
+
+    if (const Arg *A = DriverArgs.getLastArg(options::OPT_libomptarget_nvptx_path_EQ))
+      LibraryPaths.push_back(A->getValue());
 
     // Add user defined library paths from LIBRARY_PATH.
     llvm::Optional<std::string> LibPath =
@@ -665,6 +667,12 @@ void CudaToolChain::addClangTargetOptions(
         LibraryPaths.emplace_back(Path.trim());
     }
 
+    // Add path to lib / lib64 folder.
+    SmallString<256> DefaultLibPath =
+        llvm::sys::path::parent_path(getDriver().Dir);
+    llvm::sys::path::append(DefaultLibPath, Twine("lib") + CLANG_LIBDIR_SUFFIX);
+    LibraryPaths.emplace_back(DefaultLibPath.c_str());
+
     std::string LibOmpTargetName =
       "libomptarget-nvptx-" + GpuArch.str() + ".bc";
     bool FoundBCLibrary = false;