[clang] af56004 - [OpenMP] Don't pass empty files to nvlink

[Joseph Huber via cfe-commits]

Author: Joseph Huber
Date: 2022-01-20T13:12:02-05:00
New Revision: af5600420b93769a5c7981d247d37ac4d61cce54

URL: https://github.com/llvm/llvm-project/commit/af5600420b93769a5c7981d247d37ac4d61cce54
DIFF: https://github.com/llvm/llvm-project/commit/af5600420b93769a5c7981d247d37ac4d61cce54.diff

LOG: [OpenMP] Don't pass empty files to nvlink

This patch adds and exception to the nvlink wrapper tool to not pass
empty cubin files to the nvlink job. If an empty file is passed to
nvlink it will cause an error indicating that the file could not be
opened. This would occur if the user tried to link object files that
contained offloading code with a file that didnt. This will act as a
workaround until the new OpenMP offloading driver becomes the default.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D117777

Added: 
    clang/test/Driver/Inputs/openmp_static_device_link/empty.o
    clang/test/Driver/Inputs/openmp_static_device_link/lib.bc

Modified: 
    clang/test/Driver/fat_archive_nvptx.cpp
    clang/tools/clang-nvlink-wrapper/ClangNvlinkWrapper.cpp

Removed: 
    


################################################################################
diff  --git a/clang/test/Driver/Inputs/openmp_static_device_link/empty.o b/clang/test/Driver/Inputs/openmp_static_device_link/empty.o
new file mode 100644
index 0000000000000..e69de29bb2d1d

diff  --git a/clang/test/Driver/Inputs/openmp_static_device_link/lib.bc b/clang/test/Driver/Inputs/openmp_static_device_link/lib.bc
new file mode 100644
index 0000000000000..1a87fd836dba2
Binary files /dev/null and b/clang/test/Driver/Inputs/openmp_static_device_link/lib.bc 
diff er

diff  --git a/clang/test/Driver/fat_archive_nvptx.cpp b/clang/test/Driver/fat_archive_nvptx.cpp
index a46c44ff998cc..5413445925dd3 100644
--- a/clang/test/Driver/fat_archive_nvptx.cpp
+++ b/clang/test/Driver/fat_archive_nvptx.cpp
@@ -10,7 +10,8 @@
 // CHECK: clang{{.*}}"-cc1"{{.*}}"-triple" "nvptx64-nvidia-cuda"{{.*}}"-target-cpu" "[[GPU:sm_[0-9]+]]"{{.*}}"-o" "[[HOSTBC:.*.s]]" "-x" "c++"{{.*}}.cpp
 // CHECK: clang-offload-bundler" "-unbundle" "-type=a" "-inputs={{.*}}/Inputs/openmp_static_device_link/libFatArchive.a" "-targets=openmp-nvptx64-nvidia-cuda-[[GPU]]" "-outputs=[[DEVICESPECIFICARCHIVE:.*.a]]" "-allow-missing-bundles"
 // CHECK: clang-nvlink-wrapper{{.*}}"-o" "{{.*}}.out" "-arch" "[[GPU]]" "{{.*}}[[DEVICESPECIFICARCHIVE]]"
-// expected-no-diagnostics
+// RUN: not %clang -fopenmp -fopenmp-targets=nvptx64-nvidia-cuda %s %S/Inputs/openmp_static_device_link/empty.o --libomptarget-nvptx-bc-path=%S/Inputs/openmp_static_device_link/lib.bc 2>&1 | FileCheck %s --check-prefix=EMPTY
+// EMPTY-NOT: Could not open input file
 
 #ifndef HEADER
 #define HEADER

diff  --git a/clang/tools/clang-nvlink-wrapper/ClangNvlinkWrapper.cpp b/clang/tools/clang-nvlink-wrapper/ClangNvlinkWrapper.cpp
index 46a4f30ba8817..7ccc284a48314 100644
--- a/clang/tools/clang-nvlink-wrapper/ClangNvlinkWrapper.cpp
+++ b/clang/tools/clang-nvlink-wrapper/ClangNvlinkWrapper.cpp
@@ -55,12 +55,22 @@ static cl::opt<std::string> NvlinkUserPath("nvlink-path",
 static cl::list<std::string>
     NVArgs(cl::Sink, cl::desc("<options to be passed to nvlink>..."));
 
+static bool isEmptyFile(StringRef Filename) {
+  ErrorOr<std::unique_ptr<MemoryBuffer>> BufOrErr =
+      MemoryBuffer::getFileOrSTDIN(Filename, false, false);
+  if (std::error_code EC = BufOrErr.getError())
+    return false;
+  return (*BufOrErr)->getBuffer().empty();
+}
+
 static Error runNVLink(std::string NVLinkPath,
                        SmallVectorImpl<std::string> &Args) {
   std::vector<StringRef> NVLArgs;
   NVLArgs.push_back(NVLinkPath);
+  StringRef Output = *(llvm::find(Args, "-o") + 1);
   for (auto &Arg : Args) {
-    NVLArgs.push_back(Arg);
+    if (!(sys::fs::exists(Arg) && Arg != Output && isEmptyFile(Arg)))
+      NVLArgs.push_back(Arg);
   }
 
   if (sys::ExecuteAndWait(NVLinkPath, NVLArgs))