[PATCH] D124292: [OpenMP] Use CUDA's non-RDC mode when LTO has whole program visibility

[Joseph Huber via Phabricator via cfe-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG3530c35c6609: [OpenMP] Use CUDA's non-RDC mode when LTO has whole program visibility (authored by jhuber6).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124292/new/

https://reviews.llvm.org/D124292

Files:
  clang/test/Driver/linker-wrapper.c
  clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp


Index: clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
===================================================================
--- clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
+++ clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
@@ -595,7 +595,7 @@
 // TODO: Move these to a separate file.
 namespace nvptx {
 Expected<std::string> assemble(StringRef InputFile, Triple TheTriple,
-                               StringRef Arch) {
+                               StringRef Arch, bool RDC = true) {
   // NVPTX uses the ptxas binary to create device object files.
   Expected<std::string> PtxasPath = findProgram("ptxas", {CudaBinaryPath});
   if (!PtxasPath)
@@ -626,7 +626,8 @@
   CmdArgs.push_back(Opt);
   CmdArgs.push_back("--gpu-name");
   CmdArgs.push_back(Arch);
-  CmdArgs.push_back("-c");
+  if (RDC)
+    CmdArgs.push_back("-c");
 
   CmdArgs.push_back(InputFile);
 
@@ -933,7 +934,8 @@
 }
 
 Error linkBitcodeFiles(SmallVectorImpl<std::string> &InputFiles,
-                       const Triple &TheTriple, StringRef Arch) {
+                       const Triple &TheTriple, StringRef Arch,
+                       bool &WholeProgram) {
   SmallVector<std::unique_ptr<MemoryBuffer>, 4> SavedBuffers;
   SmallVector<std::unique_ptr<lto::InputFile>, 4> BitcodeFiles;
   SmallVector<std::string, 4> NewInputFiles;
@@ -1009,7 +1011,7 @@
   };
 
   // We assume visibility of the whole program if every input file was bitcode.
-  bool WholeProgram = BitcodeFiles.size() == InputFiles.size();
+  WholeProgram = BitcodeFiles.size() == InputFiles.size();
   auto LTOBackend =
       (EmbedBitcode) ? createLTO(TheTriple, Arch, WholeProgram, OutputBitcode)
                      : createLTO(TheTriple, Arch, WholeProgram);
@@ -1089,7 +1091,7 @@
   // Is we are compiling for NVPTX we need to run the assembler first.
   if (TheTriple.isNVPTX() && !EmbedBitcode) {
     for (auto &File : Files) {
-      auto FileOrErr = nvptx::assemble(File, TheTriple, Arch);
+      auto FileOrErr = nvptx::assemble(File, TheTriple, Arch, !WholeProgram);
       if (!FileOrErr)
         return FileOrErr.takeError();
       File = *FileOrErr;
@@ -1117,10 +1119,11 @@
   for (auto &LinkerInput : LinkerInputMap) {
     DeviceFile &File = LinkerInput.getFirst();
     Triple TheTriple = Triple(File.TheTriple);
+    bool WholeProgram = false;
 
     // Run LTO on any bitcode files and replace the input with the result.
-    if (Error Err =
-            linkBitcodeFiles(LinkerInput.getSecond(), TheTriple, File.Arch))
+    if (Error Err = linkBitcodeFiles(LinkerInput.getSecond(), TheTriple,
+                                     File.Arch, WholeProgram))
       return Err;
 
     // If we are embedding bitcode for JIT, skip the final device linking.
@@ -1130,6 +1133,14 @@
       continue;
     }
 
+    // If we performed LTO on NVPTX and had whole program visibility, we can use
+    // CUDA in non-RDC mode.
+    if (WholeProgram && TheTriple.isNVPTX()) {
+      assert(!LinkerInput.getSecond().empty() && "No non-RDC image to embed");
+      LinkedImages.push_back(LinkerInput.getSecond().front());
+      continue;
+    }
+
     auto ImageOrErr = linkDevice(LinkerInput.getSecond(), TheTriple, File.Arch);
     if (!ImageOrErr)
       return ImageOrErr.takeError();
Index: clang/test/Driver/linker-wrapper.c
===================================================================
--- clang/test/Driver/linker-wrapper.c
+++ clang/test/Driver/linker-wrapper.c
@@ -38,5 +38,5 @@
 // RUN: clang-linker-wrapper --host-triple x86_64-unknown-linux-gnu --dry-run -linker-path \
 // RUN:   /usr/bin/ld -- %t.o -o a.out 2>&1 | FileCheck %s --check-prefix=LTO
 
-// LTO: ptxas{{.*}}-m64 -o {{.*}}.cubin -O2 --gpu-name sm_70 -c {{.*}}.s
-// LTO: nvlink{{.*}}-m64 -o {{.*}}.out -arch sm_70 {{.*}}.cubin
+// LTO: ptxas{{.*}}-m64 -o {{.*}}.cubin -O2 --gpu-name sm_70 {{.*}}.s
+// LTO-NOT: nvlink


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D124292.424730.patch
Type: text/x-patch
Size: 3890 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20220423/0f476cd3/attachment.bin>