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"
19 #include "llvm/ADT/SmallVector.h"
24 // Object file magic string.
25 const char WasmMagic[] = {'\0', 'a', 's', 'm'};
26 // Wasm binary format version
27 const uint32_t WasmVersion = 0x1;
28 // Wasm linking metadata version
29 const uint32_t WasmMetadataVersion = 0x2;
30 // Wasm uses a 64k page size
31 const uint32_t WasmPageSize = 65536;
33 struct WasmObjectHeader {
38 struct WasmDylinkInfo {
39 uint32_t MemorySize; // Memory size in bytes
40 uint32_t MemoryAlignment; // P2 alignment of memory
41 uint32_t TableSize; // Table size in elements
42 uint32_t TableAlignment; // P2 alignment of table
43 std::vector<StringRef> Needed; // Shared library depenedencies
74 struct WasmGlobalType {
82 WasmInitExpr InitExpr;
83 StringRef SymbolName; // from the "linking" section
86 struct WasmEventType {
87 // Kind of event. Currently only WASM_EVENT_ATTRIBUTE_EXCEPTION is possible.
95 StringRef SymbolName; // from the "linking" section
104 WasmGlobalType Global;
111 struct WasmLocalDecl {
116 struct WasmFunction {
118 std::vector<WasmLocalDecl> Locals;
119 ArrayRef<uint8_t> Body;
120 uint32_t CodeSectionOffset;
122 uint32_t CodeOffset; // start of Locals and Body
123 StringRef SymbolName; // from the "linking" section
124 StringRef DebugName; // from the "name" section
125 uint32_t Comdat; // from the "comdat info" section
128 struct WasmDataSegment {
129 uint32_t MemoryIndex;
131 ArrayRef<uint8_t> Content;
132 StringRef Name; // from the "segment info" section
135 uint32_t Comdat; // from the "comdat info" section
138 struct WasmElemSegment {
141 std::vector<uint32_t> Functions;
144 // Represents the location of a Wasm data symbol within a WasmDataSegment, as
145 // the index of the segment, and the offset and size within the segment.
146 struct WasmDataReference {
152 struct WasmRelocation {
153 uint8_t Type; // The type of the relocation.
154 uint32_t Index; // Index into either symbol or type index space.
155 uint64_t Offset; // Offset from the start of the section.
156 int64_t Addend; // A value to add to the symbol.
159 struct WasmInitFunc {
164 struct WasmSymbolInfo {
168 StringRef Module; // For undefined symbols the module name of the import
170 // For function or global symbols, the index in function or global index
172 uint32_t ElementIndex;
173 // For a data symbols, the address of the data relative to segment.
174 WasmDataReference DataRef;
178 struct WasmFunctionName {
183 struct WasmLinkingData {
185 std::vector<WasmInitFunc> InitFunctions;
186 std::vector<StringRef> Comdats;
187 std::vector<WasmSymbolInfo> SymbolTable;
191 WASM_SEC_CUSTOM = 0, // Custom / User-defined section
192 WASM_SEC_TYPE = 1, // Function signature declarations
193 WASM_SEC_IMPORT = 2, // Import declarations
194 WASM_SEC_FUNCTION = 3, // Function declarations
195 WASM_SEC_TABLE = 4, // Indirect function table and other tables
196 WASM_SEC_MEMORY = 5, // Memory attributes
197 WASM_SEC_GLOBAL = 6, // Global declarations
198 WASM_SEC_EXPORT = 7, // Exports
199 WASM_SEC_START = 8, // Start function declaration
200 WASM_SEC_ELEM = 9, // Elements section
201 WASM_SEC_CODE = 10, // Function bodies (code)
202 WASM_SEC_DATA = 11, // Data segments
203 WASM_SEC_DATACOUNT = 12, // Data segment count
204 WASM_SEC_EVENT = 13 // Event declarations
207 // Type immediate encodings used in various contexts.
209 WASM_TYPE_I32 = 0x7F,
210 WASM_TYPE_I64 = 0x7E,
211 WASM_TYPE_F32 = 0x7D,
212 WASM_TYPE_F64 = 0x7C,
213 WASM_TYPE_V128 = 0x7B,
214 WASM_TYPE_FUNCREF = 0x70,
215 WASM_TYPE_EXCEPT_REF = 0x68,
216 WASM_TYPE_FUNC = 0x60,
217 WASM_TYPE_NORESULT = 0x40, // for blocks with no result values
220 // Kinds of externals (for imports and exports).
222 WASM_EXTERNAL_FUNCTION = 0x0,
223 WASM_EXTERNAL_TABLE = 0x1,
224 WASM_EXTERNAL_MEMORY = 0x2,
225 WASM_EXTERNAL_GLOBAL = 0x3,
226 WASM_EXTERNAL_EVENT = 0x4,
229 // Opcodes used in initializer expressions.
231 WASM_OPCODE_END = 0x0b,
232 WASM_OPCODE_GLOBAL_GET = 0x23,
233 WASM_OPCODE_I32_CONST = 0x41,
234 WASM_OPCODE_I64_CONST = 0x42,
235 WASM_OPCODE_F32_CONST = 0x43,
236 WASM_OPCODE_F64_CONST = 0x44,
240 WASM_LIMITS_FLAG_HAS_MAX = 0x1,
241 WASM_LIMITS_FLAG_IS_SHARED = 0x2,
244 // Kind codes used in the custom "name" section
246 WASM_NAMES_FUNCTION = 0x1,
247 WASM_NAMES_LOCAL = 0x2,
250 // Kind codes used in the custom "linking" section
252 WASM_SEGMENT_INFO = 0x5,
253 WASM_INIT_FUNCS = 0x6,
254 WASM_COMDAT_INFO = 0x7,
255 WASM_SYMBOL_TABLE = 0x8,
258 // Kind codes used in the custom "linking" section in the WASM_COMDAT_INFO
260 WASM_COMDAT_DATA = 0x0,
261 WASM_COMDAT_FUNCTION = 0x1,
264 // Kind codes used in the custom "linking" section in the WASM_SYMBOL_TABLE
265 enum WasmSymbolType : unsigned {
266 WASM_SYMBOL_TYPE_FUNCTION = 0x0,
267 WASM_SYMBOL_TYPE_DATA = 0x1,
268 WASM_SYMBOL_TYPE_GLOBAL = 0x2,
269 WASM_SYMBOL_TYPE_SECTION = 0x3,
270 WASM_SYMBOL_TYPE_EVENT = 0x4,
273 // Kinds of event attributes.
274 enum WasmEventAttribute : unsigned {
275 WASM_EVENT_ATTRIBUTE_EXCEPTION = 0x0,
278 const unsigned WASM_SYMBOL_BINDING_MASK = 0x3;
279 const unsigned WASM_SYMBOL_VISIBILITY_MASK = 0xc;
281 const unsigned WASM_SYMBOL_BINDING_GLOBAL = 0x0;
282 const unsigned WASM_SYMBOL_BINDING_WEAK = 0x1;
283 const unsigned WASM_SYMBOL_BINDING_LOCAL = 0x2;
284 const unsigned WASM_SYMBOL_VISIBILITY_DEFAULT = 0x0;
285 const unsigned WASM_SYMBOL_VISIBILITY_HIDDEN = 0x4;
286 const unsigned WASM_SYMBOL_UNDEFINED = 0x10;
288 #define WASM_RELOC(name, value) name = value,
291 #include "WasmRelocs.def"
296 // Subset of types that a value can have
302 V128 = WASM_TYPE_V128,
303 EXCEPT_REF = WASM_TYPE_EXCEPT_REF,
306 struct WasmSignature {
307 SmallVector<wasm::ValType, 1> Returns;
308 SmallVector<wasm::ValType, 4> Params;
309 // Support empty and tombstone instances, needed by DenseMap.
310 enum { Plain, Empty, Tombstone } State = Plain;
312 WasmSignature(SmallVector<wasm::ValType, 1> &&InReturns,
313 SmallVector<wasm::ValType, 4> &&InParams)
314 : Returns(InReturns), Params(InParams) {}
315 WasmSignature() = default;
318 // Useful comparison operators
319 inline bool operator==(const WasmSignature &LHS, const WasmSignature &RHS) {
320 return LHS.State == RHS.State && LHS.Returns == RHS.Returns &&
321 LHS.Params == RHS.Params;
324 inline bool operator!=(const WasmSignature &LHS, const WasmSignature &RHS) {
325 return !(LHS == RHS);
328 inline bool operator==(const WasmGlobalType &LHS, const WasmGlobalType &RHS) {
329 return LHS.Type == RHS.Type && LHS.Mutable == RHS.Mutable;
332 inline bool operator!=(const WasmGlobalType &LHS, const WasmGlobalType &RHS) {
333 return !(LHS == RHS);
336 std::string toString(wasm::WasmSymbolType type);
337 std::string relocTypetoString(uint32_t type);
339 } // end namespace wasm
340 } // end namespace llvm