1 //===--- Offloading.h - Utilities for handling offloading code -*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains the binary format used for budingling device metadata with 10 // an associated device image. The data can then be stored inside a host object 11 // file to create a fat binary and read by the linker. This is intended to be a 12 // thin wrapper around the image itself. If this format becomes sufficiently 13 // complex it should be moved to a standard binary format like msgpack or ELF. 14 // 15 //===----------------------------------------------------------------------===// 16 17 #ifndef LLVM_OBJECT_OFFLOADBINARY_H 18 #define LLVM_OBJECT_OFFLOADBINARY_H 19 20 #include "llvm/ADT/MapVector.h" 21 #include "llvm/ADT/SmallString.h" 22 #include "llvm/ADT/StringRef.h" 23 #include "llvm/Object/Binary.h" 24 #include "llvm/Support/Error.h" 25 #include "llvm/Support/MemoryBuffer.h" 26 #include <memory> 27 28 namespace llvm { 29 30 namespace object { 31 32 /// The producer of the associated offloading image. 33 enum OffloadKind : uint16_t { 34 OFK_None = 0, 35 OFK_OpenMP, 36 OFK_Cuda, 37 OFK_HIP, 38 OFK_LAST, 39 }; 40 41 /// The type of contents the offloading image contains. 42 enum ImageKind : uint16_t { 43 IMG_None = 0, 44 IMG_Object, 45 IMG_Bitcode, 46 IMG_Cubin, 47 IMG_Fatbinary, 48 IMG_PTX, 49 IMG_LAST, 50 }; 51 52 /// A simple binary serialization of an offloading file. We use this format to 53 /// embed the offloading image into the host executable so it can be extracted 54 /// and used by the linker. 55 /// 56 /// Many of these could be stored in the same section by the time the linker 57 /// sees it so we mark this information with a header. The version is used to 58 /// detect ABI stability and the size is used to find other offloading entries 59 /// that may exist in the same section. All offsets are given as absolute byte 60 /// offsets from the beginning of the file. 61 class OffloadBinary : public Binary { 62 public: 63 using string_iterator = MapVector<StringRef, StringRef>::const_iterator; 64 using string_iterator_range = iterator_range<string_iterator>; 65 66 /// The current version of the binary used for backwards compatibility. 67 static const uint32_t Version = 1; 68 69 /// The offloading metadata that will be serialized to a memory buffer. 70 struct OffloadingImage { 71 ImageKind TheImageKind; 72 OffloadKind TheOffloadKind; 73 uint32_t Flags; 74 MapVector<StringRef, StringRef> StringData; 75 std::unique_ptr<MemoryBuffer> Image; 76 }; 77 78 /// Attempt to parse the offloading binary stored in \p Data. 79 static Expected<std::unique_ptr<OffloadBinary>> create(MemoryBufferRef); 80 81 /// Serialize the contents of \p File to a binary buffer to be read later. 82 static SmallString<0> write(const OffloadingImage &); 83 84 static uint64_t getAlignment() { return 8; } 85 86 ImageKind getImageKind() const { return TheEntry->TheImageKind; } 87 OffloadKind getOffloadKind() const { return TheEntry->TheOffloadKind; } 88 uint32_t getVersion() const { return TheHeader->Version; } 89 uint32_t getFlags() const { return TheEntry->Flags; } 90 uint64_t getSize() const { return TheHeader->Size; } 91 92 StringRef getTriple() const { return getString("triple"); } 93 StringRef getArch() const { return getString("arch"); } 94 StringRef getImage() const { 95 return StringRef(&Buffer[TheEntry->ImageOffset], TheEntry->ImageSize); 96 } 97 98 // Iterator over all the key and value pairs in the binary. 99 string_iterator_range strings() const { 100 return string_iterator_range(StringData.begin(), StringData.end()); 101 } 102 103 StringRef getString(StringRef Key) const { return StringData.lookup(Key); } 104 105 static bool classof(const Binary *V) { return V->isOffloadFile(); } 106 107 struct Header { 108 uint8_t Magic[4] = {0x10, 0xFF, 0x10, 0xAD}; // 0x10FF10AD magic bytes. 109 uint32_t Version = OffloadBinary::Version; // Version identifier. 110 uint64_t Size; // Size in bytes of this entire binary. 111 uint64_t EntryOffset; // Offset of the metadata entry in bytes. 112 uint64_t EntrySize; // Size of the metadata entry in bytes. 113 }; 114 115 struct Entry { 116 ImageKind TheImageKind; // The kind of the image stored. 117 OffloadKind TheOffloadKind; // The producer of this image. 118 uint32_t Flags; // Additional flags associated with the image. 119 uint64_t StringOffset; // Offset in bytes to the string map. 120 uint64_t NumStrings; // Number of entries in the string map. 121 uint64_t ImageOffset; // Offset in bytes of the actual binary image. 122 uint64_t ImageSize; // Size in bytes of the binary image. 123 }; 124 125 struct StringEntry { 126 uint64_t KeyOffset; 127 uint64_t ValueOffset; 128 }; 129 130 private: 131 OffloadBinary(MemoryBufferRef Source, const Header *TheHeader, 132 const Entry *TheEntry) 133 : Binary(Binary::ID_Offload, Source), Buffer(Source.getBufferStart()), 134 TheHeader(TheHeader), TheEntry(TheEntry) { 135 const StringEntry *StringMapBegin = 136 reinterpret_cast<const StringEntry *>(&Buffer[TheEntry->StringOffset]); 137 for (uint64_t I = 0, E = TheEntry->NumStrings; I != E; ++I) { 138 StringRef Key = &Buffer[StringMapBegin[I].KeyOffset]; 139 StringData[Key] = &Buffer[StringMapBegin[I].ValueOffset]; 140 } 141 } 142 143 OffloadBinary(const OffloadBinary &Other) = delete; 144 145 /// Map from keys to offsets in the binary. 146 MapVector<StringRef, StringRef> StringData; 147 /// Raw pointer to the MemoryBufferRef for convenience. 148 const char *Buffer; 149 /// Location of the header within the binary. 150 const Header *TheHeader; 151 /// Location of the metadata entries within the binary. 152 const Entry *TheEntry; 153 }; 154 155 /// A class to contain the binary information for a single OffloadBinary that 156 /// owns its memory. 157 class OffloadFile : public OwningBinary<OffloadBinary> { 158 public: 159 using TargetID = std::pair<StringRef, StringRef>; 160 161 OffloadFile(std::unique_ptr<OffloadBinary> Binary, 162 std::unique_ptr<MemoryBuffer> Buffer) 163 : OwningBinary<OffloadBinary>(std::move(Binary), std::move(Buffer)) {} 164 165 /// Make a deep copy of this offloading file. 166 OffloadFile copy() const { 167 std::unique_ptr<MemoryBuffer> Buffer = MemoryBuffer::getMemBufferCopy( 168 getBinary()->getMemoryBufferRef().getBuffer()); 169 170 // This parsing should never fail because it has already been parsed. 171 auto NewBinaryOrErr = OffloadBinary::create(*Buffer); 172 assert(NewBinaryOrErr && "Failed to parse a copy of the binary?"); 173 if (!NewBinaryOrErr) 174 llvm::consumeError(NewBinaryOrErr.takeError()); 175 return OffloadFile(std::move(*NewBinaryOrErr), std::move(Buffer)); 176 } 177 178 /// We use the Triple and Architecture pair to group linker inputs together. 179 /// This conversion function lets us use these inputs in a hash-map. 180 operator TargetID() const { 181 return std::make_pair(getBinary()->getTriple(), getBinary()->getArch()); 182 } 183 }; 184 185 /// Extracts embedded device offloading code from a memory \p Buffer to a list 186 /// of \p Binaries. 187 Error extractOffloadBinaries(MemoryBufferRef Buffer, 188 SmallVectorImpl<OffloadFile> &Binaries); 189 190 /// Convert a string \p Name to an image kind. 191 ImageKind getImageKind(StringRef Name); 192 193 /// Convert an image kind to its string representation. 194 StringRef getImageKindName(ImageKind Name); 195 196 /// Convert a string \p Name to an offload kind. 197 OffloadKind getOffloadKind(StringRef Name); 198 199 /// Convert an offload kind to its string representation. 200 StringRef getOffloadKindName(OffloadKind Name); 201 202 /// If the target is AMD we check the target IDs for mutual compatibility. A 203 /// target id is a string conforming to the folowing BNF syntax: 204 /// 205 /// target-id ::= '<arch> ( : <feature> ( '+' | '-' ) )*' 206 /// 207 /// The features 'xnack' and 'sramecc' are currently supported. These can be in 208 /// the state of on, off, and any when unspecified. A target marked as any can 209 /// bind with either on or off. This is used to link mutually compatible 210 /// architectures together. Returns false in the case of an exact match. 211 bool areTargetsCompatible(const OffloadFile::TargetID &LHS, 212 const OffloadFile::TargetID &RHS); 213 214 } // namespace object 215 216 } // namespace llvm 217 #endif 218