1 //===- Wasm.h - Wasm object file format -------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines manifest constants for the wasm object file format.
11 // See: https://github.com/WebAssembly/design/blob/master/BinaryEncoding.md
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_BINARYFORMAT_WASM_H
16 #define LLVM_BINARYFORMAT_WASM_H
18 #include "llvm/ADT/ArrayRef.h"
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 // Wasm uses a 64k page size
28 const uint32_t WasmPageSize = 65536;
30 struct WasmObjectHeader {
35 struct WasmSignature {
36 std::vector<int32_t> ParamTypes;
71 WasmInitExpr InitExpr;
86 struct WasmLocalDecl {
92 std::vector<WasmLocalDecl> Locals;
93 ArrayRef<uint8_t> Body;
96 struct WasmDataSegment {
99 ArrayRef<uint8_t> Content;
102 struct WasmElemSegment {
105 std::vector<uint32_t> Functions;
108 struct WasmRelocation {
109 uint32_t Type; // The type of the relocation.
110 int32_t Index; // Index into function to global index space.
111 uint64_t Offset; // Offset from the start of the section.
112 int64_t Addend; // A value to add to the symbol.
116 WASM_SEC_CUSTOM = 0, // Custom / User-defined section
117 WASM_SEC_TYPE = 1, // Function signature declarations
118 WASM_SEC_IMPORT = 2, // Import declarations
119 WASM_SEC_FUNCTION = 3, // Function declarations
120 WASM_SEC_TABLE = 4, // Indirect function table and other tables
121 WASM_SEC_MEMORY = 5, // Memory attributes
122 WASM_SEC_GLOBAL = 6, // Global declarations
123 WASM_SEC_EXPORT = 7, // Exports
124 WASM_SEC_START = 8, // Start function declaration
125 WASM_SEC_ELEM = 9, // Elements section
126 WASM_SEC_CODE = 10, // Function bodies (code)
127 WASM_SEC_DATA = 11 // Data segments
130 // Type immediate encodings used in various contexts.
132 WASM_TYPE_I32 = -0x01,
133 WASM_TYPE_I64 = -0x02,
134 WASM_TYPE_F32 = -0x03,
135 WASM_TYPE_F64 = -0x04,
136 WASM_TYPE_ANYFUNC = -0x10,
137 WASM_TYPE_FUNC = -0x20,
138 WASM_TYPE_NORESULT = -0x40, // for blocks with no result values
141 // Kinds of externals (for imports and exports).
143 WASM_EXTERNAL_FUNCTION = 0x0,
144 WASM_EXTERNAL_TABLE = 0x1,
145 WASM_EXTERNAL_MEMORY = 0x2,
146 WASM_EXTERNAL_GLOBAL = 0x3,
149 // Opcodes used in initializer expressions.
151 WASM_OPCODE_END = 0x0b,
152 WASM_OPCODE_GET_GLOBAL = 0x23,
153 WASM_OPCODE_I32_CONST = 0x41,
154 WASM_OPCODE_I64_CONST = 0x42,
155 WASM_OPCODE_F32_CONST = 0x43,
156 WASM_OPCODE_F64_CONST = 0x44,
160 WASM_NAMES_FUNCTION = 0x1,
161 WASM_NAMES_LOCAL = 0x2,
165 WASM_LIMITS_FLAG_HAS_MAX = 0x1,
168 // Subset of types that a value can have
176 // Linking metadata kinds.
178 WASM_STACK_POINTER = 0x1,
181 #define WASM_RELOC(name, value) name = value,
184 #include "WasmRelocs/WebAssembly.def"
193 // The initial value for this global is either the value of an imported
194 // global, in which case InitialModule and InitialName specify the global
195 // import, or a value, in which case InitialModule is empty and InitialValue
197 StringRef InitialModule;
198 StringRef InitialName;
199 uint64_t InitialValue;
202 } // end namespace wasm
203 } // end namespace llvm