vzakhari created this revision.
vzakhari added reviewers: saiislam, jdoerfert.
Herald added a reviewer: alexander-shaposhnikov.
vzakhari requested review of this revision.
Herald added subscribers: cfe-commits, sstefan1.
Herald added a project: clang.
This code cannot currently work within llorg, because it is mostly based on
https://github.com/intel/llvm state of clang-offload-wrapper. This patch is
uploaded to facilitate discussion at OpenMP at LLVM weekly meeting.
The code shows how to containerize several offload images passed to
clang-offload-wrapper into a single ELF file. It also re-implements the
LLVMOMPOFFLOAD notes embedding that currently uses llvm-objcopy in llorg.
The implementation uses yaml::yaml2elf utility.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D112103
Files:
clang/tools/clang-offload-wrapper/ClangOffloadWrapper.cpp
Index: clang/tools/clang-offload-wrapper/ClangOffloadWrapper.cpp
===================================================================
--- clang/tools/clang-offload-wrapper/ClangOffloadWrapper.cpp
+++ clang/tools/clang-offload-wrapper/ClangOffloadWrapper.cpp
@@ -26,6 +26,8 @@
#include "llvm/IR/Module.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Object/ObjectFile.h"
+#include "llvm/ObjectYAML/ELFYAML.h"
+#include "llvm/ObjectYAML/yaml2obj.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/Errc.h"
@@ -388,6 +390,181 @@
return M;
}
+ Expected<StringRef> getTmpFile(Twine NamePattern) {
+ Expected<sys::fs::TempFile> TempFile =
+ sys::fs::TempFile::create(NamePattern);
+ if (!TempFile)
+ return TempFile.takeError();
+
+ std::string FileName = TempFile->TmpName;
+
+ if (Error E = TempFile->keep(FileName))
+ return std::move(E);
+
+ TempFiles.push_back(std::move(FileName));
+ return TempFiles.back();
+ }
+
+ void containerizeOpenMPImages() {
+ // If there are no OpenMP images, there is nothing to do.
+ auto OpenMPPackIt = Packs.find(OffloadKind::OpenMP);
+ if (OpenMPPackIt == Packs.end())
+ return;
+ SameKindPack *OpenMPPack = OpenMPPackIt->second.get();
+
+ // Start creating notes for the ELF container.
+ std::vector<ELFYAML::NoteEntry> Notes;
+ std::string ImgVersion = toHex(OPENMP_OFFLOAD_IMAGE_VERSION);
+ Notes.emplace_back(ELFYAML::NoteEntry{"LLVMOMPOFFLOAD",
+ yaml::BinaryRef(ImgVersion),
+ ELF::NT_LLVM_OPENMP_OFFLOAD_VERSION});
+ std::string Producer = toHex("LLVM");
+ Notes.emplace_back(ELFYAML::NoteEntry{"LLVMOMPOFFLOAD",
+ yaml::BinaryRef(Producer),
+ ELF::NT_LLVM_OPENMP_OFFLOAD_PRODUCER});
+ std::string ProdVersion = toHex(LLVM_VERSION_STRING
+#ifdef LLVM_REVISION
+ " " LLVM_REVISION
+#endif
+ );
+ Notes.emplace_back(ELFYAML::NoteEntry{"LLVMOMPOFFLOAD",
+ yaml::BinaryRef(ProdVersion),
+ ELF::NT_LLVM_OPENMP_OFFLOAD_PRODUCER_VERSION});
+
+ SmallVector<StringRef, 2> ImageFiles;
+
+ // Find SPIR-V images and create notes with auxiliary information
+ // for each of them.
+ unsigned ImageIdx = 0;
+ for (auto I = OpenMPPack->begin(); I != OpenMPPack->end(); ++I) {
+ const BinaryWrapper::Image &Img = *(I->get());
+ if (Img.Tgt.find("spir") != 0)
+ continue;
+
+ ImageFiles.push_back(Img.File);
+ ++ImageIdx;
+ }
+
+ // If there are no SPIR-V images, there is nothing to do.
+ if (ImageIdx == 0)
+ return;
+
+ StringRef ToolNameRef(ToolName);
+
+ // Helper to emit warnings.
+ auto warningOS = [ToolNameRef]() -> raw_ostream & {
+ return WithColor::warning(errs(), ToolNameRef);
+ };
+ auto handleErrorAsWarning = [&warningOS](Error E) {
+ logAllUnhandledErrors(std::move(E), warningOS());
+ };
+
+ // Reserve a temporary file for the ELF image.
+ Expected<StringRef> ImageFileName =
+ getTmpFile(Output + Twine(".spirv.elfimage.%%%%%%%.tmp"));
+ if (!ImageFileName) {
+ logAllUnhandledErrors(ImageFileName.takeError(), warningOS());
+ return;
+ }
+
+ std::error_code EC;
+ raw_fd_ostream ELFOS(ImageFileName->str(), EC);
+ if (EC) {
+ warningOS() << "cannot open ELF file " << ImageFileName->str() << ": "
+ << EC.message() << "\n";
+ return;
+ }
+
+ // Write ELF file using yaml2elf instead of writing ELF by ourselves.
+ // We use 64-bit little-endian ELF currently.
+ ELFYAML::FileHeader Header{};
+ Header.Class = ELF::ELFCLASS64;
+ Header.Data = ELF::ELFDATA2LSB;
+ Header.Type = ELF::ET_NONE;
+ // Do not use any existing machine, otherwise, other plugins
+ // may claim this image.
+ Header.Machine = ELF::EM_NONE;
+
+ // Create a section with notes.
+ ELFYAML::NoteSection Section{};
+ Section.Type = ELF::SHT_NOTE;
+ Section.Name = ".note.openmp";
+ Section.Notes.emplace(std::move(Notes));
+
+ // The main ELFYAML structure describing our ELF container.
+ ELFYAML::Object Object{};
+ Object.Header = Header;
+ Object.Chunks.push_back(
+ std::make_unique<ELFYAML::NoteSection>(std::move(Section)));
+
+ SmallVector<std::unique_ptr<MemoryBuffer>, 4> Buffers;
+ SmallVector<std::string, 4> SectionNames;
+
+ ImageIdx = 0;
+ // Put each image into its own __openmp_offload_spirv_# section.
+ for (auto Name : ImageFiles) {
+ // Read the image into a memory buffer.
+ ErrorOr<std::unique_ptr<MemoryBuffer>> BufOrErr =
+ MemoryBuffer::getFile(Name);
+ if (!BufOrErr) {
+ handleErrorAsWarning(
+ createFileError(Name, BufOrErr.getError()));
+ return;
+ }
+ Buffers.push_back(std::move(*BufOrErr));
+
+ // Create a new section for the image.
+ ELFYAML::RawContentSection Section{};
+ Section.Info = yaml::Hex64(0);
+ Section.Type = ELF::SHT_PROGBITS;
+ SectionNames.emplace_back(
+ ("__openmp_offload_spirv_" + Twine(ImageIdx)).str());
+ Section.Name = SectionNames.back();
+ Section.Content = yaml::BinaryRef(makeArrayRef(
+ reinterpret_cast<const uint8_t *>(Buffers.back()->getBufferStart()),
+ Buffers.back()->getBufferSize()));
+
+ // Put the new section into the ELFYAML::Object.
+ Object.Chunks.push_back(
+ std::make_unique<ELFYAML::RawContentSection>(std::move(Section)));
+ ++ImageIdx;
+ }
+
+ yaml::ErrorHandler ErrHandler =
+ [&warningOS](const Twine &Msg) {
+ warningOS() << "cannot convert YAML to ELF: " << Msg << "\n";
+ };
+
+ if (!yaml::yaml2elf(Object, ELFOS, ErrHandler, UINT64_MAX)) {
+ warningOS() << "YAML to ELF conversion failed.\n";
+ return;
+ }
+ ELFOS.close();
+
+ if (ELFOS.has_error()) {
+ warningOS() << "cannot write ELF file " << ImageFileName->str() << ": "
+ << ELFOS.error().message() << "\n";
+ ELFOS.clear_error();
+ return;
+ }
+
+ // Delete the original Images from the list and replace them
+ // with a single combined container ELF.
+ for (auto I = OpenMPPack->begin(); I != OpenMPPack->end();) {
+ const BinaryWrapper::Image &Img = *(I->get());
+ if (Img.Tgt.find("spir") != 0)
+ ++I;
+ else
+ I = OpenMPPack->erase(I);
+ }
+
+ OpenMPPack->emplace_back(std::make_unique<Image>(
+ *ImageFileName, "",
+ "spirv",
+ BinaryImageFormat::none, "", "",
+ "", ""));
+ }
+
std::unique_ptr<MemoryBuffer> addELFNotes(std::unique_ptr<MemoryBuffer> Buf,
StringRef OriginalFileName) {
// Cannot add notes, if llvm-objcopy is not available.
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