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Diffstat (limited to 'tools/clang-offload-wrapper/ClangOffloadWrapper.cpp')
| -rw-r--r-- | tools/clang-offload-wrapper/ClangOffloadWrapper.cpp | 371 |
1 files changed, 371 insertions, 0 deletions
diff --git a/tools/clang-offload-wrapper/ClangOffloadWrapper.cpp b/tools/clang-offload-wrapper/ClangOffloadWrapper.cpp new file mode 100644 index 000000000000..c3863422adf6 --- /dev/null +++ b/tools/clang-offload-wrapper/ClangOffloadWrapper.cpp @@ -0,0 +1,371 @@ +//===-- clang-offload-wrapper/ClangOffloadWrapper.cpp -----------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +/// +/// \file +/// Implementation of the offload wrapper tool. It takes offload target binaries +/// as input and creates wrapper bitcode file containing target binaries +/// packaged as data. Wrapper bitcode also includes initialization code which +/// registers target binaries in offloading runtime at program startup. +/// +//===----------------------------------------------------------------------===// + +#include "clang/Basic/Version.h" +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/Triple.h" +#include "llvm/Bitcode/BitcodeWriter.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/GlobalVariable.h" +#include "llvm/IR/IRBuilder.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/Module.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Errc.h" +#include "llvm/Support/Error.h" +#include "llvm/Support/ErrorOr.h" +#include "llvm/Support/MemoryBuffer.h" +#include "llvm/Support/Signals.h" +#include "llvm/Support/ToolOutputFile.h" +#include "llvm/Support/WithColor.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Transforms/Utils/ModuleUtils.h" +#include <cassert> +#include <cstdint> + +using namespace llvm; + +static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden); + +// Mark all our options with this category, everything else (except for -version +// and -help) will be hidden. +static cl::OptionCategory + ClangOffloadWrapperCategory("clang-offload-wrapper options"); + +static cl::opt<std::string> Output("o", cl::Required, + cl::desc("Output filename"), + cl::value_desc("filename"), + cl::cat(ClangOffloadWrapperCategory)); + +static cl::list<std::string> Inputs(cl::Positional, cl::OneOrMore, + cl::desc("<input files>"), + cl::cat(ClangOffloadWrapperCategory)); + +static cl::opt<std::string> + Target("target", cl::Required, + cl::desc("Target triple for the output module"), + cl::value_desc("triple"), cl::cat(ClangOffloadWrapperCategory)); + +namespace { + +class BinaryWrapper { + LLVMContext C; + Module M; + + StructType *EntryTy = nullptr; + StructType *ImageTy = nullptr; + StructType *DescTy = nullptr; + +private: + IntegerType *getSizeTTy() { + switch (M.getDataLayout().getPointerTypeSize(Type::getInt8PtrTy(C))) { + case 4u: + return Type::getInt32Ty(C); + case 8u: + return Type::getInt64Ty(C); + } + llvm_unreachable("unsupported pointer type size"); + } + + // struct __tgt_offload_entry { + // void *addr; + // char *name; + // size_t size; + // int32_t flags; + // int32_t reserved; + // }; + StructType *getEntryTy() { + if (!EntryTy) + EntryTy = StructType::create("__tgt_offload_entry", Type::getInt8PtrTy(C), + Type::getInt8PtrTy(C), getSizeTTy(), + Type::getInt32Ty(C), Type::getInt32Ty(C)); + return EntryTy; + } + + PointerType *getEntryPtrTy() { return PointerType::getUnqual(getEntryTy()); } + + // struct __tgt_device_image { + // void *ImageStart; + // void *ImageEnd; + // __tgt_offload_entry *EntriesBegin; + // __tgt_offload_entry *EntriesEnd; + // }; + StructType *getDeviceImageTy() { + if (!ImageTy) + ImageTy = StructType::create("__tgt_device_image", Type::getInt8PtrTy(C), + Type::getInt8PtrTy(C), getEntryPtrTy(), + getEntryPtrTy()); + return ImageTy; + } + + PointerType *getDeviceImagePtrTy() { + return PointerType::getUnqual(getDeviceImageTy()); + } + + // struct __tgt_bin_desc { + // int32_t NumDeviceImages; + // __tgt_device_image *DeviceImages; + // __tgt_offload_entry *HostEntriesBegin; + // __tgt_offload_entry *HostEntriesEnd; + // }; + StructType *getBinDescTy() { + if (!DescTy) + DescTy = StructType::create("__tgt_bin_desc", Type::getInt32Ty(C), + getDeviceImagePtrTy(), getEntryPtrTy(), + getEntryPtrTy()); + return DescTy; + } + + PointerType *getBinDescPtrTy() { + return PointerType::getUnqual(getBinDescTy()); + } + + /// Creates binary descriptor for the given device images. Binary descriptor + /// is an object that is passed to the offloading runtime at program startup + /// and it describes all device images available in the executable or shared + /// library. It is defined as follows + /// + /// __attribute__((visibility("hidden"))) + /// extern __tgt_offload_entry *__start_omp_offloading_entries; + /// __attribute__((visibility("hidden"))) + /// extern __tgt_offload_entry *__stop_omp_offloading_entries; + /// + /// static const char Image0[] = { <Bufs.front() contents> }; + /// ... + /// static const char ImageN[] = { <Bufs.back() contents> }; + /// + /// static const __tgt_device_image Images[] = { + /// { + /// Image0, /*ImageStart*/ + /// Image0 + sizeof(Image0), /*ImageEnd*/ + /// __start_omp_offloading_entries, /*EntriesBegin*/ + /// __stop_omp_offloading_entries /*EntriesEnd*/ + /// }, + /// ... + /// { + /// ImageN, /*ImageStart*/ + /// ImageN + sizeof(ImageN), /*ImageEnd*/ + /// __start_omp_offloading_entries, /*EntriesBegin*/ + /// __stop_omp_offloading_entries /*EntriesEnd*/ + /// } + /// }; + /// + /// static const __tgt_bin_desc BinDesc = { + /// sizeof(Images) / sizeof(Images[0]), /*NumDeviceImages*/ + /// Images, /*DeviceImages*/ + /// __start_omp_offloading_entries, /*HostEntriesBegin*/ + /// __stop_omp_offloading_entries /*HostEntriesEnd*/ + /// }; + /// + /// Global variable that represents BinDesc is returned. + GlobalVariable *createBinDesc(ArrayRef<ArrayRef<char>> Bufs) { + // Create external begin/end symbols for the offload entries table. + auto *EntriesB = new GlobalVariable( + M, getEntryTy(), /*isConstant*/ true, GlobalValue::ExternalLinkage, + /*Initializer*/ nullptr, "__start_omp_offloading_entries"); + EntriesB->setVisibility(GlobalValue::HiddenVisibility); + auto *EntriesE = new GlobalVariable( + M, getEntryTy(), /*isConstant*/ true, GlobalValue::ExternalLinkage, + /*Initializer*/ nullptr, "__stop_omp_offloading_entries"); + EntriesE->setVisibility(GlobalValue::HiddenVisibility); + + // We assume that external begin/end symbols that we have created above will + // be defined by the linker. But linker will do that only if linker inputs + // have section with "omp_offloading_entries" name which is not guaranteed. + // So, we just create dummy zero sized object in the offload entries section + // to force linker to define those symbols. + auto *DummyInit = + ConstantAggregateZero::get(ArrayType::get(getEntryTy(), 0u)); + auto *DummyEntry = new GlobalVariable( + M, DummyInit->getType(), true, GlobalVariable::ExternalLinkage, + DummyInit, "__dummy.omp_offloading.entry"); + DummyEntry->setSection("omp_offloading_entries"); + DummyEntry->setVisibility(GlobalValue::HiddenVisibility); + + auto *Zero = ConstantInt::get(getSizeTTy(), 0u); + Constant *ZeroZero[] = {Zero, Zero}; + + // Create initializer for the images array. + SmallVector<Constant *, 4u> ImagesInits; + ImagesInits.reserve(Bufs.size()); + for (ArrayRef<char> Buf : Bufs) { + auto *Data = ConstantDataArray::get(C, Buf); + auto *Image = new GlobalVariable(M, Data->getType(), /*isConstant*/ true, + GlobalVariable::InternalLinkage, Data, + ".omp_offloading.device_image"); + Image->setUnnamedAddr(GlobalValue::UnnamedAddr::Global); + + auto *Size = ConstantInt::get(getSizeTTy(), Buf.size()); + Constant *ZeroSize[] = {Zero, Size}; + + auto *ImageB = ConstantExpr::getGetElementPtr(Image->getValueType(), + Image, ZeroZero); + auto *ImageE = ConstantExpr::getGetElementPtr(Image->getValueType(), + Image, ZeroSize); + + ImagesInits.push_back(ConstantStruct::get(getDeviceImageTy(), ImageB, + ImageE, EntriesB, EntriesE)); + } + + // Then create images array. + auto *ImagesData = ConstantArray::get( + ArrayType::get(getDeviceImageTy(), ImagesInits.size()), ImagesInits); + + auto *Images = + new GlobalVariable(M, ImagesData->getType(), /*isConstant*/ true, + GlobalValue::InternalLinkage, ImagesData, + ".omp_offloading.device_images"); + Images->setUnnamedAddr(GlobalValue::UnnamedAddr::Global); + + auto *ImagesB = ConstantExpr::getGetElementPtr(Images->getValueType(), + Images, ZeroZero); + + // And finally create the binary descriptor object. + auto *DescInit = ConstantStruct::get( + getBinDescTy(), + ConstantInt::get(Type::getInt32Ty(C), ImagesInits.size()), ImagesB, + EntriesB, EntriesE); + + return new GlobalVariable(M, DescInit->getType(), /*isConstant*/ true, + GlobalValue::InternalLinkage, DescInit, + ".omp_offloading.descriptor"); + } + + void createRegisterFunction(GlobalVariable *BinDesc) { + auto *FuncTy = FunctionType::get(Type::getVoidTy(C), /*isVarArg*/ false); + auto *Func = Function::Create(FuncTy, GlobalValue::InternalLinkage, + ".omp_offloading.descriptor_reg", &M); + Func->setSection(".text.startup"); + + // Get __tgt_register_lib function declaration. + auto *RegFuncTy = FunctionType::get(Type::getVoidTy(C), getBinDescPtrTy(), + /*isVarArg*/ false); + FunctionCallee RegFuncC = + M.getOrInsertFunction("__tgt_register_lib", RegFuncTy); + + // Construct function body + IRBuilder<> Builder(BasicBlock::Create(C, "entry", Func)); + Builder.CreateCall(RegFuncC, BinDesc); + Builder.CreateRetVoid(); + + // Add this function to constructors. + appendToGlobalCtors(M, Func, 0); + } + + void createUnregisterFunction(GlobalVariable *BinDesc) { + auto *FuncTy = FunctionType::get(Type::getVoidTy(C), /*isVarArg*/ false); + auto *Func = Function::Create(FuncTy, GlobalValue::InternalLinkage, + ".omp_offloading.descriptor_unreg", &M); + Func->setSection(".text.startup"); + + // Get __tgt_unregister_lib function declaration. + auto *UnRegFuncTy = FunctionType::get(Type::getVoidTy(C), getBinDescPtrTy(), + /*isVarArg*/ false); + FunctionCallee UnRegFuncC = + M.getOrInsertFunction("__tgt_unregister_lib", UnRegFuncTy); + + // Construct function body + IRBuilder<> Builder(BasicBlock::Create(C, "entry", Func)); + Builder.CreateCall(UnRegFuncC, BinDesc); + Builder.CreateRetVoid(); + + // Add this function to global destructors. + appendToGlobalDtors(M, Func, 0); + } + +public: + BinaryWrapper(StringRef Target) : M("offload.wrapper.object", C) { + M.setTargetTriple(Target); + } + + const Module &wrapBinaries(ArrayRef<ArrayRef<char>> Binaries) { + GlobalVariable *Desc = createBinDesc(Binaries); + assert(Desc && "no binary descriptor"); + createRegisterFunction(Desc); + createUnregisterFunction(Desc); + return M; + } +}; + +} // anonymous namespace + +int main(int argc, const char **argv) { + sys::PrintStackTraceOnErrorSignal(argv[0]); + + cl::HideUnrelatedOptions(ClangOffloadWrapperCategory); + cl::SetVersionPrinter([](raw_ostream &OS) { + OS << clang::getClangToolFullVersion("clang-offload-wrapper") << '\n'; + }); + cl::ParseCommandLineOptions( + argc, argv, + "A tool to create a wrapper bitcode for offload target binaries. Takes " + "offload\ntarget binaries as input and produces bitcode file containing " + "target binaries packaged\nas data and initialization code which " + "registers target binaries in offload runtime.\n"); + + if (Help) { + cl::PrintHelpMessage(); + return 0; + } + + auto reportError = [argv](Error E) { + logAllUnhandledErrors(std::move(E), WithColor::error(errs(), argv[0])); + }; + + if (Triple(Target).getArch() == Triple::UnknownArch) { + reportError(createStringError( + errc::invalid_argument, "'" + Target + "': unsupported target triple")); + return 1; + } + + // Read device binaries. + SmallVector<std::unique_ptr<MemoryBuffer>, 4u> Buffers; + SmallVector<ArrayRef<char>, 4u> Images; + Buffers.reserve(Inputs.size()); + Images.reserve(Inputs.size()); + for (const std::string &File : Inputs) { + ErrorOr<std::unique_ptr<MemoryBuffer>> BufOrErr = + MemoryBuffer::getFileOrSTDIN(File); + if (!BufOrErr) { + reportError(createFileError(File, BufOrErr.getError())); + return 1; + } + const std::unique_ptr<MemoryBuffer> &Buf = + Buffers.emplace_back(std::move(*BufOrErr)); + Images.emplace_back(Buf->getBufferStart(), Buf->getBufferSize()); + } + + // Create the output file to write the resulting bitcode to. + std::error_code EC; + ToolOutputFile Out(Output, EC, sys::fs::OF_None); + if (EC) { + reportError(createFileError(Output, EC)); + return 1; + } + + // Create a wrapper for device binaries and write its bitcode to the file. + WriteBitcodeToFile(BinaryWrapper(Target).wrapBinaries( + makeArrayRef(Images.data(), Images.size())), + Out.os()); + if (Out.os().has_error()) { + reportError(createFileError(Output, Out.os().error())); + return 1; + } + + // Success. + Out.keep(); + return 0; +} |