[clang] 9da4d74 - [Clang] Always pass detected CUDA path to 'clang-nvlink-wrapper' (#152789)

[via cfe-commits]

Author: Joseph Huber
Date: 2025-08-11T07:22:11-05:00
New Revision: 9da4d74a8865e32289273e7122d44863baf64ee8

URL: https://github.com/llvm/llvm-project/commit/9da4d74a8865e32289273e7122d44863baf64ee8
DIFF: https://github.com/llvm/llvm-project/commit/9da4d74a8865e32289273e7122d44863baf64ee8.diff

LOG: [Clang] Always pass detected CUDA path to 'clang-nvlink-wrapper' (#152789)

Summary:
We always want to use the detected path. The clang driver's detection is
far more sophisticated so we should use that whenever possible. Also
update the usage so we properly fall back to path instead of incorrectly
using the `/bin` if not provided.

Added: 
    

Modified: 
    clang/lib/Driver/ToolChains/Cuda.cpp
    clang/test/Driver/cuda-cross-compiling.c
    clang/tools/clang-nvlink-wrapper/ClangNVLinkWrapper.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Driver/ToolChains/Cuda.cpp b/clang/lib/Driver/ToolChains/Cuda.cpp
index fdfcea852b4f2..327cb5183f837 100644
--- a/clang/lib/Driver/ToolChains/Cuda.cpp
+++ b/clang/lib/Driver/ToolChains/Cuda.cpp
@@ -611,9 +611,12 @@ void NVPTX::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back(Args.MakeArgString(
         "--pxtas-path=" + Args.getLastArgValue(options::OPT_ptxas_path_EQ)));
 
-  if (Args.hasArg(options::OPT_cuda_path_EQ))
-    CmdArgs.push_back(Args.MakeArgString(
-        "--cuda-path=" + Args.getLastArgValue(options::OPT_cuda_path_EQ)));
+  if (Args.hasArg(options::OPT_cuda_path_EQ) || TC.CudaInstallation.isValid()) {
+    StringRef CudaPath = Args.getLastArgValue(
+        options::OPT_cuda_path_EQ,
+        llvm::sys::path::parent_path(TC.CudaInstallation.getBinPath()));
+    CmdArgs.push_back(Args.MakeArgString("--cuda-path=" + CudaPath));
+  }
 
   // Add paths specified in LIBRARY_PATH environment variable as -L options.
   addDirectoryList(Args, CmdArgs, "-L", "LIBRARY_PATH");

diff  --git a/clang/test/Driver/cuda-cross-compiling.c b/clang/test/Driver/cuda-cross-compiling.c
index 1df231ecb4479..6717ae82d0e70 100644
--- a/clang/test/Driver/cuda-cross-compiling.c
+++ b/clang/test/Driver/cuda-cross-compiling.c
@@ -104,3 +104,11 @@
 // RUN:   -nogpulib -nogpuinc -### %s 2>&1 | FileCheck -check-prefix=STARTUP %s
 
 // STARTUP: clang-nvlink-wrapper{{.*}}"-lc" "-lm" "{{.*}}crt1.o"
+
+//
+// Test cuda path handling
+//
+// RUN: %clang -target nvptx64-nvidia-cuda -march=sm_52 --cuda-path=%S/Inputs/CUDA/usr/local/cuda \
+// RUN:   -nogpulib -nogpuinc -### %s 2>&1 | FileCheck -check-prefix=PATH %s
+
+// PATH: clang-nvlink-wrapper{{.*}}"--cuda-path={{.*}}/Inputs/CUDA/usr/local/cuda"

diff  --git a/clang/tools/clang-nvlink-wrapper/ClangNVLinkWrapper.cpp b/clang/tools/clang-nvlink-wrapper/ClangNVLinkWrapper.cpp
index 4b63971214f81..58eb671c61989 100644
--- a/clang/tools/clang-nvlink-wrapper/ClangNVLinkWrapper.cpp
+++ b/clang/tools/clang-nvlink-wrapper/ClangNVLinkWrapper.cpp
@@ -286,12 +286,16 @@ struct Symbol {
 };
 
 Expected<StringRef> runPTXAs(StringRef File, const ArgList &Args) {
-  std::string CudaPath = Args.getLastArgValue(OPT_cuda_path_EQ).str();
-  std::string GivenPath = Args.getLastArgValue(OPT_ptxas_path_EQ).str();
-  Expected<std::string> PTXAsPath =
-      findProgram(Args, "ptxas", {CudaPath + "/bin", GivenPath});
+  SmallVector<StringRef, 1> SearchPaths;
+  if (Arg *A = Args.getLastArg(OPT_cuda_path_EQ))
+    SearchPaths.push_back(Args.MakeArgString(A->getValue() + Twine("/bin")));
+  if (Arg *A = Args.getLastArg(OPT_ptxas_path_EQ))
+    SearchPaths.push_back(Args.MakeArgString(A->getValue()));
+
+  Expected<std::string> PTXAsPath = findProgram(Args, "ptxas", SearchPaths);
   if (!PTXAsPath)
     return PTXAsPath.takeError();
+
   if (!Args.hasArg(OPT_arch))
     return createStringError(
         "must pass in an explicit nvptx64 gpu architecture to 'ptxas'");
@@ -691,9 +695,11 @@ Error runNVLink(ArrayRef<StringRef> Files, const ArgList &Args) {
   if (Args.hasArg(OPT_lto_emit_asm) || Args.hasArg(OPT_lto_emit_llvm))
     return Error::success();
 
-  std::string CudaPath = Args.getLastArgValue(OPT_cuda_path_EQ).str();
-  Expected<std::string> NVLinkPath =
-      findProgram(Args, "nvlink", {CudaPath + "/bin"});
+  SmallVector<StringRef, 1> SearchPaths;
+  if (Arg *A = Args.getLastArg(OPT_cuda_path_EQ))
+    SearchPaths.push_back(Args.MakeArgString(A->getValue() + Twine("/bin")));
+
+  Expected<std::string> NVLinkPath = findProgram(Args, "nvlink", SearchPaths);
   if (!NVLinkPath)
     return NVLinkPath.takeError();