1 //===- Wasm.h - Wasm object file format -------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines manifest constants for the wasm object file format. 11 // See: https://github.com/WebAssembly/design/blob/master/BinaryEncoding.md 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_SUPPORT_WASM_H 16 #define LLVM_SUPPORT_WASM_H 17 18 #include "llvm/ADT/ArrayRef.h" 19 20 namespace llvm { 21 namespace wasm { 22 23 // Object file magic string. 24 const char WasmMagic[] = {'\0', 'a', 's', 'm'}; 25 // Wasm binary format version 26 const uint32_t WasmVersion = 0x1; 27 28 struct WasmObjectHeader { 29 StringRef Magic; 30 uint32_t Version; 31 }; 32 33 struct WasmSignature { 34 std::vector<int32_t> ParamTypes; 35 int32_t ReturnType; 36 }; 37 38 struct WasmImport { 39 StringRef Module; 40 StringRef Field; 41 uint32_t Kind; 42 union { 43 uint32_t SigIndex; 44 int32_t GlobalType; 45 }; 46 bool GlobalMutable; 47 }; 48 49 struct WasmExport { 50 StringRef Name; 51 uint32_t Kind; 52 uint32_t Index; 53 }; 54 55 struct WasmLimits { 56 uint32_t Flags; 57 uint32_t Initial; 58 uint32_t Maximum; 59 }; 60 61 struct WasmTable { 62 int32_t ElemType; 63 WasmLimits Limits; 64 }; 65 66 struct WasmInitExpr { 67 uint8_t Opcode; 68 union { 69 int32_t Int32; 70 int64_t Int64; 71 int32_t Float32; 72 int64_t Float64; 73 uint32_t Global; 74 } Value; 75 }; 76 77 struct WasmGlobal { 78 int32_t Type; 79 bool Mutable; 80 WasmInitExpr InitExpr; 81 }; 82 83 struct WasmLocalDecl { 84 int32_t Type; 85 uint32_t Count; 86 }; 87 88 struct WasmFunction { 89 std::vector<WasmLocalDecl> Locals; 90 ArrayRef<uint8_t> Body; 91 }; 92 93 struct WasmDataSegment { 94 uint32_t Index; 95 WasmInitExpr Offset; 96 ArrayRef<uint8_t> Content; 97 }; 98 99 struct WasmElemSegment { 100 uint32_t TableIndex; 101 WasmInitExpr Offset; 102 std::vector<uint32_t> Functions; 103 }; 104 105 struct WasmRelocation { 106 uint32_t Type; // The type of the relocation. 107 int32_t Index; // Index into function to global index space. 108 uint64_t Offset; // Offset from the start of the section. 109 uint64_t Addend; // A value to add to the symbol. 110 }; 111 112 enum : unsigned { 113 WASM_SEC_CUSTOM = 0, // Custom / User-defined section 114 WASM_SEC_TYPE = 1, // Function signature declarations 115 WASM_SEC_IMPORT = 2, // Import declarations 116 WASM_SEC_FUNCTION = 3, // Function declarations 117 WASM_SEC_TABLE = 4, // Indirect function table and other tables 118 WASM_SEC_MEMORY = 5, // Memory attributes 119 WASM_SEC_GLOBAL = 6, // Global declarations 120 WASM_SEC_EXPORT = 7, // Exports 121 WASM_SEC_START = 8, // Start function declaration 122 WASM_SEC_ELEM = 9, // Elements section 123 WASM_SEC_CODE = 10, // Function bodies (code) 124 WASM_SEC_DATA = 11 // Data segments 125 }; 126 127 // Type immediate encodings used in various contexts. 128 enum { 129 WASM_TYPE_I32 = -0x01, 130 WASM_TYPE_I64 = -0x02, 131 WASM_TYPE_F32 = -0x03, 132 WASM_TYPE_F64 = -0x04, 133 WASM_TYPE_ANYFUNC = -0x10, 134 WASM_TYPE_FUNC = -0x20, 135 WASM_TYPE_NORESULT = -0x40, // for blocks with no result values 136 }; 137 138 // Kinds of externals (for imports and exports). 139 enum : unsigned { 140 WASM_EXTERNAL_FUNCTION = 0x0, 141 WASM_EXTERNAL_TABLE = 0x1, 142 WASM_EXTERNAL_MEMORY = 0x2, 143 WASM_EXTERNAL_GLOBAL = 0x3, 144 }; 145 146 // Opcodes used in initializer expressions. 147 enum : unsigned { 148 WASM_OPCODE_END = 0x0b, 149 WASM_OPCODE_GET_GLOBAL = 0x23, 150 WASM_OPCODE_I32_CONST = 0x41, 151 WASM_OPCODE_I64_CONST = 0x42, 152 WASM_OPCODE_F32_CONST = 0x43, 153 WASM_OPCODE_F64_CONST = 0x44, 154 }; 155 156 enum : unsigned { 157 WASM_NAMES_FUNCTION = 0x1, 158 WASM_NAMES_LOCAL = 0x2, 159 }; 160 161 enum : unsigned { 162 WASM_LIMITS_FLAG_HAS_MAX = 0x1, 163 }; 164 165 // Subset of types that a value can have 166 enum class ValType { 167 I32 = WASM_TYPE_I32, 168 I64 = WASM_TYPE_I64, 169 F32 = WASM_TYPE_F32, 170 F64 = WASM_TYPE_F64, 171 }; 172 173 // Linking metadata kinds. 174 enum : unsigned { 175 WASM_STACK_POINTER = 0x1, 176 }; 177 178 #define WASM_RELOC(name, value) name = value, 179 180 enum : unsigned { 181 #include "WasmRelocs/WebAssembly.def" 182 }; 183 184 #undef WASM_RELOC 185 186 struct Global { 187 ValType Type; 188 bool Mutable; 189 190 // The initial value for this global is either the value of an imported 191 // global, in which case InitialModule and InitialName specify the global 192 // import, or a value, in which case InitialModule is empty and InitialValue 193 // holds the value. 194 StringRef InitialModule; 195 StringRef InitialName; 196 uint64_t InitialValue; 197 }; 198 199 } // end namespace wasm 200 } // end namespace llvm 201 202 #endif 203
