[SYCL] Add clang-linker-wrapper changes to call clang-sycl-linker for SYCL offloads

clang/docs/ClangOffloadPackager.rst

@@ -112,6 +112,8 @@ the following values for the :ref:`offload kind<table-offload_kind>` and the
     +------------+-------+---------------------------------------+
     | OFK_HIP    | 0x03  | The producer was HIP                  |
     +------------+-------+---------------------------------------+
+    | OFK_SYCL   | 0x04  | The producer was SYCL                 |
+    +------------+-------+---------------------------------------+
 
 The flags are used to signify certain conditions, such as the presence of
 debugging information or whether or not LTO was used. The string entry table is

clang/test/Driver/clang-sycl-linker-test.cpp

@@ -8,15 +8,15 @@
 // RUN: clang-sycl-linker --dry-run -v -triple=spirv64 %t_1.bc %t_2.bc -o a.spv 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=SIMPLE-FO
 // SIMPLE-FO: sycl-device-link: inputs: {{.*}}.bc, {{.*}}.bc  libfiles:  output: [[LLVMLINKOUT:.*]].bc
-// SIMPLE-FO-NEXT: SPIR-V Backend: input: [[LLVMLINKOUT]].bc, output: a.spv
+// SIMPLE-FO-NEXT: SPIR-V Backend: input: [[LLVMLINKOUT]].bc, output: a_0.spv
 //
 // Test the dry run of a simple case with device library files specified.
 // RUN: touch %T/lib1.bc
 // RUN: touch %T/lib2.bc
 // RUN: clang-sycl-linker --dry-run -v -triple=spirv64 %t_1.bc %t_2.bc --library-path=%T --device-libs=lib1.bc,lib2.bc -o a.spv 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=DEVLIBS
 // DEVLIBS: sycl-device-link: inputs: {{.*}}.bc  libfiles: {{.*}}lib1.bc, {{.*}}lib2.bc  output: [[LLVMLINKOUT:.*]].bc
-// DEVLIBS-NEXT: SPIR-V Backend: input: [[LLVMLINKOUT]].bc, output: a.spv
+// DEVLIBS-NEXT: SPIR-V Backend: input: [[LLVMLINKOUT]].bc, output: a_0.spv
 //
 // Test a simple case with a random file (not bitcode) as input.
 // RUN: touch %t.o

clang/test/Driver/linker-wrapper.c

@@ -2,13 +2,15 @@
 // REQUIRES: x86-registered-target
 // REQUIRES: nvptx-registered-target
 // REQUIRES: amdgpu-registered-target
+// REQUIRES: spirv-registered-target
 
 // An externally visible variable so static libraries extract.
 __attribute__((visibility("protected"), used)) int x;
 
 // RUN: %clang -cc1 %s -triple x86_64-unknown-linux-gnu -emit-obj -o %t.elf.o
 // RUN: %clang -cc1 %s -triple nvptx64-nvidia-cuda -emit-llvm-bc -o %t.nvptx.bc
 // RUN: %clang -cc1 %s -triple amdgcn-amd-amdhsa -emit-llvm-bc -o %t.amdgpu.bc
+// RUN: %clang -cc1 %s -triple spirv64-unknown-unknown -emit-llvm-bc -o %t.spirv.bc
 
 // RUN: clang-offload-packager -o %t.out \
 // RUN:   --image=file=%t.elf.o,kind=openmp,triple=nvptx64-nvidia-cuda,arch=sm_70 \
@@ -49,6 +51,14 @@ __attribute__((visibility("protected"), used)) int x;
 
 // AMDGPU-LTO-TEMPS: clang{{.*}} --target=amdgcn-amd-amdhsa -mcpu=gfx1030 -flto {{.*}}-save-temps
 
+// RUN: clang-offload-packager -o %t.out \
+// RUN:   --image=file=%t.spirv.bc,kind=sycl,triple=spirv64-unknown-unknown,arch=generic
+// RUN: %clang -cc1 %s -triple x86_64-unknown-linux-gnu -emit-obj -o %t.o -fembed-offload-object=%t.out
+// RUN: not clang-linker-wrapper --host-triple=x86_64-unknown-linux-gnu --dry-run \
+// RUN:   --linker-path=/usr/bin/ld %t.o -o a.out 2>&1 | FileCheck %s --check-prefix=SPIRV-LINK
+
+// SPIRV-LINK: clang{{.*}} -o {{.*}}.img --target=spirv64-unknown-unknown {{.*}}.o --sycl-link -Xlinker -triple=spirv64-unknown-unknown -Xlinker -arch=
+
 // RUN: clang-offload-packager -o %t.out \
 // RUN:   --image=file=%t.elf.o,kind=openmp,triple=x86_64-unknown-linux-gnu \
 // RUN:   --image=file=%t.elf.o,kind=openmp,triple=x86_64-unknown-linux-gnu

clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp

@@ -464,7 +464,8 @@ fatbinary(ArrayRef<std::pair<StringRef, StringRef>> InputFiles,
 } // namespace amdgcn
 
 namespace generic {
-Expected<StringRef> clang(ArrayRef<StringRef> InputFiles, const ArgList &Args) {
+Expected<StringRef> clang(ArrayRef<StringRef> InputFiles, const ArgList &Args,
+                          uint16_t ActiveOffloadKindMask) {
   llvm::TimeTraceScope TimeScope("Clang");
   // Use `clang` to invoke the appropriate device tools.
   Expected<std::string> ClangPath =
@@ -554,6 +555,17 @@ Expected<StringRef> clang(ArrayRef<StringRef> InputFiles, const ArgList &Args) {
   if (Args.hasArg(OPT_embed_bitcode))
     CmdArgs.push_back("-Wl,--lto-emit-llvm");
 
+  // For linking device code with the SYCL offload kind, special handling is
+  // required. Passing --sycl-link to clang results in a call to
+  // clang-sycl-linker. Additional linker flags required by clang-sycl-linker
+  // will be communicated via the -Xlinker option.
+  if (ActiveOffloadKindMask & OFK_SYCL) {
+    CmdArgs.push_back("--sycl-link");
+    CmdArgs.append(
+        {"-Xlinker", Args.MakeArgString("-triple=" + Triple.getTriple())});
+    CmdArgs.append({"-Xlinker", Args.MakeArgString("-arch=" + Arch)});
+  }
+
   for (StringRef Arg : Args.getAllArgValues(OPT_linker_arg_EQ))
     CmdArgs.append({"-Xlinker", Args.MakeArgString(Arg)});
   for (StringRef Arg : Args.getAllArgValues(OPT_compiler_arg_EQ))
@@ -567,7 +579,8 @@ Expected<StringRef> clang(ArrayRef<StringRef> InputFiles, const ArgList &Args) {
 } // namespace generic
 
 Expected<StringRef> linkDevice(ArrayRef<StringRef> InputFiles,
-                               const ArgList &Args) {
+                               const ArgList &Args,
+                               uint16_t ActiveOffloadKindMask) {
   const llvm::Triple Triple(Args.getLastArgValue(OPT_triple_EQ));
   switch (Triple.getArch()) {
   case Triple::nvptx:
@@ -582,7 +595,7 @@ Expected<StringRef> linkDevice(ArrayRef<StringRef> InputFiles,
   case Triple::spirv64:
   case Triple::systemz:
   case Triple::loongarch64:
-    return generic::clang(InputFiles, Args);
+    return generic::clang(InputFiles, Args, ActiveOffloadKindMask);
   default:
     return createStringError(Triple.getArchName() +
                              " linking is not supported");
@@ -792,6 +805,7 @@ bundleLinkedOutput(ArrayRef<OffloadingImage> Images, const ArgList &Args,
   llvm::TimeTraceScope TimeScope("Bundle linked output");
   switch (Kind) {
   case OFK_OpenMP:
+  case OFK_SYCL:
     return bundleOpenMP(Images);
   case OFK_Cuda:
     return bundleCuda(Images, Args);
@@ -927,6 +941,14 @@ Expected<SmallVector<StringRef>> linkAndWrapDeviceFiles(
     for (const auto &File : Input)
       ActiveOffloadKindMask |= File.getBinary()->getOffloadKind();
 
+    // Linking images of SYCL offload kind with images of other kind is not
+    // supported.
+    // TODO: Remove the above limitation.
+    if ((ActiveOffloadKindMask & OFK_SYCL) &&
+        ((ActiveOffloadKindMask ^ OFK_SYCL) != 0))
+      return createStringError("Linking images of SYCL offload kind with "
+                               "images of any other kind is not supported");
+
     // Write any remaining device inputs to an output file.
     SmallVector<StringRef> InputFiles;
     for (const OffloadFile &File : Input) {
@@ -937,7 +959,8 @@ Expected<SmallVector<StringRef>> linkAndWrapDeviceFiles(
     }
 
     // Link the remaining device files using the device linker.
-    auto OutputOrErr = linkDevice(InputFiles, LinkerArgs);
+    auto OutputOrErr =
+        linkDevice(InputFiles, LinkerArgs, ActiveOffloadKindMask);
     if (!OutputOrErr)
       return OutputOrErr.takeError();
 

clang/tools/clang-sycl-linker/ClangSYCLLinker.cpp

@@ -70,6 +70,8 @@ static StringRef OutputFile;
 /// Directory to dump SPIR-V IR if requested by user.
 static SmallString<128> SPIRVDumpDir;
 
+using OffloadingImage = OffloadBinary::OffloadingImage;
+
 static void printVersion(raw_ostream &OS) {
   OS << clang::getClangToolFullVersion("clang-sycl-linker") << '\n';
 }
@@ -278,8 +280,8 @@ Expected<StringRef> linkDeviceCode(ArrayRef<std::string> InputFiles,
 /// Converts 'File' from LLVM bitcode to SPIR-V format using SPIR-V backend.
 /// 'Args' encompasses all arguments required for linking device code and will
 /// be parsed to generate options required to be passed into the backend.
-static Expected<StringRef> runSPIRVCodeGen(StringRef File, const ArgList &Args,
-                                           LLVMContext &C) {
+static Error runSPIRVCodeGen(StringRef File, const ArgList &Args,
+                             StringRef OutputFile, LLVMContext &C) {
   llvm::TimeTraceScope TimeScope("SPIR-V code generation");
 
   // Parse input module.
@@ -289,7 +291,7 @@ static Expected<StringRef> runSPIRVCodeGen(StringRef File, const ArgList &Args,
     return createStringError(Err.getMessage());
 
   if (Error Err = M->materializeAll())
-    return std::move(Err);
+    return Err;
 
   Triple TargetTriple(Args.getLastArgValue(OPT_triple_EQ));
   M->setTargetTriple(TargetTriple);
@@ -333,7 +335,7 @@ static Expected<StringRef> runSPIRVCodeGen(StringRef File, const ArgList &Args,
     errs() << formatv("SPIR-V Backend: input: {0}, output: {1}\n", File,
                       OutputFile);
 
-  return OutputFile;
+  return Error::success();
 }
 
 /// Performs the following steps:
@@ -349,10 +351,54 @@ Error runSYCLLink(ArrayRef<std::string> Files, const ArgList &Args) {
   if (!LinkedFile)
     reportError(LinkedFile.takeError());
 
+  // TODO: SYCL post link functionality involves device code splitting and will
+  // result in multiple bitcode codes.
+  // The following lines are placeholders to represent multiple files and will
+  // be refactored once SYCL post link support is available.
+  SmallVector<std::string> SplitModules;
+  SplitModules.emplace_back(*LinkedFile);
+
   // SPIR-V code generation step.
-  auto SPVFile = runSPIRVCodeGen(*LinkedFile, Args, C);
-  if (!SPVFile)
-    return SPVFile.takeError();
+  for (size_t I = 0, E = SplitModules.size(); I != E; ++I) {
+    auto Stem = OutputFile.rsplit('.').first;
+    std::string SPVFile(Stem);
+    SPVFile.append("_" + utostr(I) + ".spv");
+    auto Err = runSPIRVCodeGen(SplitModules[I], Args, SPVFile, C);
+    if (Err)
+      return std::move(Err);
+    SplitModules[I] = SPVFile;
+  }
+
+  // Write the final output into file.
+  int FD = -1;
+  if (std::error_code EC = sys::fs::openFileForWrite(OutputFile, FD))
+    return errorCodeToError(EC);
+  llvm::raw_fd_ostream FS(FD, /*shouldClose=*/true);
+
+  for (size_t I = 0, E = SplitModules.size(); I != E; ++I) {
+    auto File = SplitModules[I];
+    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> FileOrErr =
+        llvm::MemoryBuffer::getFileOrSTDIN(File);
+    if (std::error_code EC = FileOrErr.getError()) {
+      if (DryRun)
+        FileOrErr = MemoryBuffer::getMemBuffer("");
+      else
+        return createFileError(File, EC);
+    }
+    OffloadingImage TheImage{};
+    TheImage.TheImageKind = IMG_Object;
+    TheImage.TheOffloadKind = OFK_SYCL;
+    TheImage.StringData["triple"] =
+        Args.MakeArgString(Args.getLastArgValue(OPT_triple_EQ));
+    TheImage.StringData["arch"] =
+        Args.MakeArgString(Args.getLastArgValue(OPT_arch_EQ));
+    TheImage.Image = std::move(*FileOrErr);
+
+    llvm::SmallString<0> Buffer = OffloadBinary::write(TheImage);
+    if (Buffer.size() % OffloadBinary::getAlignment() != 0)
+      return createStringError("Offload binary has invalid size alignment");
+    FS << Buffer;
+  }
   return Error::success();
 }
 
@@ -394,7 +440,7 @@ int main(int argc, char **argv) {
   DryRun = Args.hasArg(OPT_dry_run);
   SaveTemps = Args.hasArg(OPT_save_temps);
 
-  OutputFile = "a.spv";
+  OutputFile = "a.out";
   if (Args.hasArg(OPT_o))
     OutputFile = Args.getLastArgValue(OPT_o);
 

llvm/lib/Object/OffloadBinary.cpp

@@ -301,6 +301,7 @@ OffloadKind object::getOffloadKind(StringRef Name) {
       .Case("openmp", OFK_OpenMP)
       .Case("cuda", OFK_Cuda)
       .Case("hip", OFK_HIP)
+      .Case("sycl", OFK_SYCL)
       .Default(OFK_None);
 }
 
@@ -312,6 +313,8 @@ StringRef object::getOffloadKindName(OffloadKind Kind) {
     return "cuda";
   case OFK_HIP:
     return "hip";
+  case OFK_SYCL:
+    return "sycl";
   default:
     return "none";
   }