[Clang][NVPTX] Allow passing arguments to the linker while standalone

[jhuber6]

Summary:
We support standalone compilation for the NVPTX architecture using
'nvlink' as our linker. Because of the special handling required to
transform input files to cubins, as nvlink expects for some reason, we
didn't use the standard AddLinkerInput method. However, this also meant
that we weren't forwarding options passed with -Wl to the linker. Add
this support in for the standalone toolchain path.

Revived from https://reviews.llvm.org/D149978

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-driver

Author: Joseph Huber (jhuber6)

Changes

Summary:
We support standalone compilation for the NVPTX architecture using
'nvlink' as our linker. Because of the special handling required to
transform input files to cubins, as nvlink expects for some reason, we
didn't use the standard AddLinkerInput method. However, this also meant
that we weren't forwarding options passed with -Wl to the linker. Add
this support in for the standalone toolchain path.

Revived from https://reviews.llvm.org/D149978

---

Full diff: https://github.com/llvm/llvm-project/pull/73030.diff

2 Files Affected:

• (modified) clang/lib/Driver/ToolChains/Cuda.cpp (+21-22)
• (modified) clang/test/Driver/cuda-cross-compiling.c (+8)

diff --git a/clang/lib/Driver/ToolChains/Cuda.cpp b/clang/lib/Driver/ToolChains/Cuda.cpp
index e95ff98e6c940f1..5ef8b4455c23f13 100644
--- a/clang/lib/Driver/ToolChains/Cuda.cpp
+++ b/clang/lib/Driver/ToolChains/Cuda.cpp
@@ -611,35 +611,34 @@ void NVPTX::Linker::ConstructJob(Compilation &C, const JobAction &JA,
       continue;
     }
 
-    // Currently, we only pass the input files to the linker, we do not pass
-    // any libraries that may be valid only for the host.
-    if (!II.isFilename())
-      continue;
-
     // The 'nvlink' application performs RDC-mode linking when given a '.o'
     // file and device linking when given a '.cubin' file. We always want to
     // perform device linking, so just rename any '.o' files.
     // FIXME: This should hopefully be removed if NVIDIA updates their tooling.
-    auto InputFile = getToolChain().getInputFilename(II);
-    if (llvm::sys::path::extension(InputFile) != ".cubin") {
-      // If there are no actions above this one then this is direct input and we
-      // can copy it. Otherwise the input is internal so a `.cubin` file should
-      // exist.
-      if (II.getAction() && II.getAction()->getInputs().size() == 0) {
-        const char *CubinF =
-            Args.MakeArgString(getToolChain().getDriver().GetTemporaryPath(
-                llvm::sys::path::stem(InputFile), "cubin"));
-        if (llvm::sys::fs::copy_file(InputFile, C.addTempFile(CubinF)))
-          continue;
+    if (II.isFilename()) {
+      auto InputFile = getToolChain().getInputFilename(II);
+      if (llvm::sys::path::extension(InputFile) != ".cubin") {
+        // If there are no actions above this one then this is direct input and
+        // we can copy it. Otherwise the input is internal so a `.cubin` file
+        // should exist.
+        if (II.getAction() && II.getAction()->getInputs().size() == 0) {
+          const char *CubinF =
+              Args.MakeArgString(getToolChain().getDriver().GetTemporaryPath(
+                  llvm::sys::path::stem(InputFile), "cubin"));
+          if (llvm::sys::fs::copy_file(InputFile, C.addTempFile(CubinF)))
+            continue;
 
-        CmdArgs.push_back(CubinF);
+          CmdArgs.push_back(CubinF);
+        } else {
+          SmallString<256> Filename(InputFile);
+          llvm::sys::path::replace_extension(Filename, "cubin");
+          CmdArgs.push_back(Args.MakeArgString(Filename));
+        }
       } else {
-        SmallString<256> Filename(InputFile);
-        llvm::sys::path::replace_extension(Filename, "cubin");
-        CmdArgs.push_back(Args.MakeArgString(Filename));
+        CmdArgs.push_back(Args.MakeArgString(InputFile));
       }
-    } else {
-      CmdArgs.push_back(Args.MakeArgString(InputFile));
+    } else if (!II.isNothing()) {
+      II.getInputArg().renderAsInput(Args, CmdArgs);
     }
   }
 
diff --git a/clang/test/Driver/cuda-cross-compiling.c b/clang/test/Driver/cuda-cross-compiling.c
index 12d0af3b45f32f6..5a52496838813ee 100644
--- a/clang/test/Driver/cuda-cross-compiling.c
+++ b/clang/test/Driver/cuda-cross-compiling.c
@@ -77,3 +77,11 @@
 // RUN:   | FileCheck -check-prefix=LOWERING %s
 
 // LOWERING: -cc1" "-triple" "nvptx64-nvidia-cuda" {{.*}} "-mllvm" "--nvptx-lower-global-ctor-dtor"
+
+//
+// Test passing arguments directly to nvlink.
+//
+// RUN: %clang -target nvptx64-nvidia-cuda -Wl,-v -Wl,a,b -### %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=LINKER-ARGS %s
+
+// LINKER-ARGS: nvlink{{.*}}"-v"{{.*}}"a" "b"

[jhuber6]

I have a review up to change the issue I was observing in CMake when building the libc project #73030. That is required for this to work when compiling the test suite.

[jhuber6]

Ping

[jhuber6]

Ping, once #81921 lands this patch won't cause any issues with the libc build like it does currently so I'd like to land this afterwards.