1//===- Wasm.h - Wasm object file implementation -----------------*- 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 declares the WasmObjectFile class, which implements the ObjectFile
10// interface for Wasm files.
11//
12// See: https://github.com/WebAssembly/design/blob/master/BinaryEncoding.md
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_OBJECT_WASM_H
17#define LLVM_OBJECT_WASM_H
18
19#include "llvm/ADT/ArrayRef.h"
20#include "llvm/ADT/StringRef.h"
21#include "llvm/BinaryFormat/Wasm.h"
22#include "llvm/Config/llvm-config.h"
23#include "llvm/MC/MCSymbolWasm.h"
24#include "llvm/Object/Binary.h"
25#include "llvm/Object/ObjectFile.h"
26#include "llvm/Support/Error.h"
27#include "llvm/Support/MemoryBuffer.h"
28#include <cstddef>
29#include <cstdint>
30#include <vector>
31
32namespace llvm {
33namespace object {
34
35class WasmSymbol {
36public:
37 WasmSymbol(const wasm::WasmSymbolInfo &Info,
38 const wasm::WasmGlobalType *GlobalType,
39 const wasm::WasmTableType *TableType,
40 const wasm::WasmEventType *EventType,
41 const wasm::WasmSignature *Signature)
42 : Info(Info), GlobalType(GlobalType), TableType(TableType),
43 EventType(EventType), Signature(Signature) {}
44
45 const wasm::WasmSymbolInfo &Info;
46 const wasm::WasmGlobalType *GlobalType;
47 const wasm::WasmTableType *TableType;
48 const wasm::WasmEventType *EventType;
49 const wasm::WasmSignature *Signature;
50
51 bool isTypeFunction() const {
52 return Info.Kind == wasm::WASM_SYMBOL_TYPE_FUNCTION;
53 }
54
55 bool isTypeTable() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_TABLE; }
56
57 bool isTypeData() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_DATA; }
58
59 bool isTypeGlobal() const {
60 return Info.Kind == wasm::WASM_SYMBOL_TYPE_GLOBAL;
61 }
62
63 bool isTypeSection() const {
64 return Info.Kind == wasm::WASM_SYMBOL_TYPE_SECTION;
65 }
66
67 bool isTypeEvent() const { return Info.Kind == wasm::WASM_SYMBOL_TYPE_EVENT; }
68
69 bool isDefined() const { return !isUndefined(); }
70
71 bool isUndefined() const {
72 return (Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) != 0;
73 }
74
75 bool isBindingWeak() const {
76 return getBinding() == wasm::WASM_SYMBOL_BINDING_WEAK;
77 }
78
79 bool isBindingGlobal() const {
80 return getBinding() == wasm::WASM_SYMBOL_BINDING_GLOBAL;
81 }
82
83 bool isBindingLocal() const {
84 return getBinding() == wasm::WASM_SYMBOL_BINDING_LOCAL;
85 }
86
87 unsigned getBinding() const {
88 return Info.Flags & wasm::WASM_SYMBOL_BINDING_MASK;
89 }
90
91 bool isHidden() const {
92 return getVisibility() == wasm::WASM_SYMBOL_VISIBILITY_HIDDEN;
93 }
94
95 unsigned getVisibility() const {
96 return Info.Flags & wasm::WASM_SYMBOL_VISIBILITY_MASK;
97 }
98
99 void print(raw_ostream &Out) const;
100
101#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
102 LLVM_DUMP_METHOD void dump() const;
103#endif
104};
105
106struct WasmSection {
107 WasmSection() = default;
108
109 uint32_t Type = 0; // Section type (See below)
110 uint32_t Offset = 0; // Offset with in the file
111 StringRef Name; // Section name (User-defined sections only)
112 uint32_t Comdat = UINT32_MAX; // From the "comdat info" section
113 ArrayRef<uint8_t> Content; // Section content
114 std::vector<wasm::WasmRelocation> Relocations; // Relocations for this section
115};
116
117struct WasmSegment {
118 uint32_t SectionOffset;
119 wasm::WasmDataSegment Data;
120};
121
122class WasmObjectFile : public ObjectFile {
123
124public:
125 WasmObjectFile(MemoryBufferRef Object, Error &Err);
126
127 const wasm::WasmObjectHeader &getHeader() const;
128 const WasmSymbol &getWasmSymbol(const DataRefImpl &Symb) const;
129 const WasmSymbol &getWasmSymbol(const SymbolRef &Symbol) const;
130 const WasmSection &getWasmSection(const SectionRef &Section) const;
131 const wasm::WasmRelocation &getWasmRelocation(const RelocationRef &Ref) const;
132
133 static bool classof(const Binary *v) { return v->isWasm(); }
134
135 const wasm::WasmDylinkInfo &dylinkInfo() const { return DylinkInfo; }
136 const wasm::WasmProducerInfo &getProducerInfo() const { return ProducerInfo; }
137 ArrayRef<wasm::WasmFeatureEntry> getTargetFeatures() const {
138 return TargetFeatures;
139 }
140 ArrayRef<wasm::WasmSignature> types() const { return Signatures; }
141 ArrayRef<uint32_t> functionTypes() const { return FunctionTypes; }
142 ArrayRef<wasm::WasmImport> imports() const { return Imports; }
143 ArrayRef<wasm::WasmTable> tables() const { return Tables; }
144 ArrayRef<wasm::WasmLimits> memories() const { return Memories; }
145 ArrayRef<wasm::WasmGlobal> globals() const { return Globals; }
146 ArrayRef<wasm::WasmEvent> events() const { return Events; }
147 ArrayRef<wasm::WasmExport> exports() const { return Exports; }
148 ArrayRef<WasmSymbol> syms() const { return Symbols; }
149 const wasm::WasmLinkingData &linkingData() const { return LinkingData; }
150 uint32_t getNumberOfSymbols() const { return Symbols.size(); }
151 ArrayRef<wasm::WasmElemSegment> elements() const { return ElemSegments; }
152 ArrayRef<WasmSegment> dataSegments() const { return DataSegments; }
153 ArrayRef<wasm::WasmFunction> functions() const { return Functions; }
154 ArrayRef<wasm::WasmDebugName> debugNames() const { return DebugNames; }
155 uint32_t startFunction() const { return StartFunction; }
156 uint32_t getNumImportedGlobals() const { return NumImportedGlobals; }
157 uint32_t getNumImportedTables() const { return NumImportedTables; }
158 uint32_t getNumImportedFunctions() const { return NumImportedFunctions; }
159 uint32_t getNumImportedEvents() const { return NumImportedEvents; }
160 uint32_t getNumSections() const { return Sections.size(); }
161 void moveSymbolNext(DataRefImpl &Symb) const override;
162
163 Expected<uint32_t> getSymbolFlags(DataRefImpl Symb) const override;
164
165 basic_symbol_iterator symbol_begin() const override;
166
167 basic_symbol_iterator symbol_end() const override;
168 Expected<StringRef> getSymbolName(DataRefImpl Symb) const override;
169
170 Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const override;
171 uint64_t getWasmSymbolValue(const WasmSymbol &Sym) const;
172 uint64_t getSymbolValueImpl(DataRefImpl Symb) const override;
173 uint32_t getSymbolAlignment(DataRefImpl Symb) const override;
174 uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const override;
175 Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const override;
176 Expected<section_iterator> getSymbolSection(DataRefImpl Symb) const override;
177 uint32_t getSymbolSectionId(SymbolRef Sym) const;
178
179 // Overrides from SectionRef.
180 void moveSectionNext(DataRefImpl &Sec) const override;
181 Expected<StringRef> getSectionName(DataRefImpl Sec) const override;
182 uint64_t getSectionAddress(DataRefImpl Sec) const override;
183 uint64_t getSectionIndex(DataRefImpl Sec) const override;
184 uint64_t getSectionSize(DataRefImpl Sec) const override;
185 Expected<ArrayRef<uint8_t>>
186 getSectionContents(DataRefImpl Sec) const override;
187 uint64_t getSectionAlignment(DataRefImpl Sec) const override;
188 bool isSectionCompressed(DataRefImpl Sec) const override;
189 bool isSectionText(DataRefImpl Sec) const override;
190 bool isSectionData(DataRefImpl Sec) const override;
191 bool isSectionBSS(DataRefImpl Sec) const override;
192 bool isSectionVirtual(DataRefImpl Sec) const override;
193 relocation_iterator section_rel_begin(DataRefImpl Sec) const override;
194 relocation_iterator section_rel_end(DataRefImpl Sec) const override;
195
196 // Overrides from RelocationRef.
197 void moveRelocationNext(DataRefImpl &Rel) const override;
198 uint64_t getRelocationOffset(DataRefImpl Rel) const override;
199 symbol_iterator getRelocationSymbol(DataRefImpl Rel) const override;
200 uint64_t getRelocationType(DataRefImpl Rel) const override;
201 void getRelocationTypeName(DataRefImpl Rel,
202 SmallVectorImpl<char> &Result) const override;
203
204 section_iterator section_begin() const override;
205 section_iterator section_end() const override;
206 uint8_t getBytesInAddress() const override;
207 StringRef getFileFormatName() const override;
208 Triple::ArchType getArch() const override;
209 SubtargetFeatures getFeatures() const override;
210 bool isRelocatableObject() const override;
211 bool isSharedObject() const;
212
213 struct ReadContext {
214 const uint8_t *Start;
215 const uint8_t *Ptr;
216 const uint8_t *End;
217 };
218
219private:
220 bool isValidFunctionIndex(uint32_t Index) const;
221 bool isDefinedFunctionIndex(uint32_t Index) const;
222 bool isValidGlobalIndex(uint32_t Index) const;
223 bool isValidTableNumber(uint32_t Index) const;
224 bool isDefinedGlobalIndex(uint32_t Index) const;
225 bool isDefinedTableNumber(uint32_t Index) const;
226 bool isValidEventIndex(uint32_t Index) const;
227 bool isDefinedEventIndex(uint32_t Index) const;
228 bool isValidFunctionSymbol(uint32_t Index) const;
229 bool isValidTableSymbol(uint32_t Index) const;
230 bool isValidGlobalSymbol(uint32_t Index) const;
231 bool isValidEventSymbol(uint32_t Index) const;
232 bool isValidDataSymbol(uint32_t Index) const;
233 bool isValidSectionSymbol(uint32_t Index) const;
234 wasm::WasmFunction &getDefinedFunction(uint32_t Index);
235 const wasm::WasmFunction &getDefinedFunction(uint32_t Index) const;
236 wasm::WasmGlobal &getDefinedGlobal(uint32_t Index);
237 wasm::WasmEvent &getDefinedEvent(uint32_t Index);
238
239 const WasmSection &getWasmSection(DataRefImpl Ref) const;
240 const wasm::WasmRelocation &getWasmRelocation(DataRefImpl Ref) const;
241 uint32_t getSymbolSectionIdImpl(const WasmSymbol &Symb) const;
242
243 Error parseSection(WasmSection &Sec);
244 Error parseCustomSection(WasmSection &Sec, ReadContext &Ctx);
245
246 // Standard section types
247 Error parseTypeSection(ReadContext &Ctx);
248 Error parseImportSection(ReadContext &Ctx);
249 Error parseFunctionSection(ReadContext &Ctx);
250 Error parseTableSection(ReadContext &Ctx);
251 Error parseMemorySection(ReadContext &Ctx);
252 Error parseEventSection(ReadContext &Ctx);
253 Error parseGlobalSection(ReadContext &Ctx);
254 Error parseExportSection(ReadContext &Ctx);
255 Error parseStartSection(ReadContext &Ctx);
256 Error parseElemSection(ReadContext &Ctx);
257 Error parseCodeSection(ReadContext &Ctx);
258 Error parseDataSection(ReadContext &Ctx);
259 Error parseDataCountSection(ReadContext &Ctx);
260
261 // Custom section types
262 Error parseDylinkSection(ReadContext &Ctx);
263 Error parseNameSection(ReadContext &Ctx);
264 Error parseLinkingSection(ReadContext &Ctx);
265 Error parseLinkingSectionSymtab(ReadContext &Ctx);
266 Error parseLinkingSectionComdat(ReadContext &Ctx);
267 Error parseProducersSection(ReadContext &Ctx);
268 Error parseTargetFeaturesSection(ReadContext &Ctx);
269 Error parseRelocSection(StringRef Name, ReadContext &Ctx);
270
271 wasm::WasmObjectHeader Header;
272 std::vector<WasmSection> Sections;
273 wasm::WasmDylinkInfo DylinkInfo;
274 wasm::WasmProducerInfo ProducerInfo;
275 std::vector<wasm::WasmFeatureEntry> TargetFeatures;
276 std::vector<wasm::WasmSignature> Signatures;
277 std::vector<uint32_t> FunctionTypes;
278 std::vector<wasm::WasmTable> Tables;
279 std::vector<wasm::WasmLimits> Memories;
280 std::vector<wasm::WasmGlobal> Globals;
281 std::vector<wasm::WasmEvent> Events;
282 std::vector<wasm::WasmImport> Imports;
283 std::vector<wasm::WasmExport> Exports;
284 std::vector<wasm::WasmElemSegment> ElemSegments;
285 std::vector<WasmSegment> DataSegments;
286 llvm::Optional<size_t> DataCount;
287 std::vector<wasm::WasmFunction> Functions;
288 std::vector<WasmSymbol> Symbols;
289 std::vector<wasm::WasmDebugName> DebugNames;
290 uint32_t StartFunction = -1;
291 bool HasLinkingSection = false;
292 bool HasDylinkSection = false;
293 bool SeenCodeSection = false;
294 bool HasMemory64 = false;
295 wasm::WasmLinkingData LinkingData;
296 uint32_t NumImportedGlobals = 0;
297 uint32_t NumImportedTables = 0;
298 uint32_t NumImportedFunctions = 0;
299 uint32_t NumImportedEvents = 0;
300 uint32_t CodeSection = 0;
301 uint32_t DataSection = 0;
302 uint32_t EventSection = 0;
303 uint32_t GlobalSection = 0;
304 uint32_t TableSection = 0;
305};
306
307class WasmSectionOrderChecker {
308public:
309 // We define orders for all core wasm sections and known custom sections.
310 enum : int {
311 // Sentinel, must be zero
312 WASM_SEC_ORDER_NONE = 0,
313
314 // Core sections
315 WASM_SEC_ORDER_TYPE,
316 WASM_SEC_ORDER_IMPORT,
317 WASM_SEC_ORDER_FUNCTION,
318 WASM_SEC_ORDER_TABLE,
319 WASM_SEC_ORDER_MEMORY,
320 WASM_SEC_ORDER_EVENT,
321 WASM_SEC_ORDER_GLOBAL,
322 WASM_SEC_ORDER_EXPORT,
323 WASM_SEC_ORDER_START,
324 WASM_SEC_ORDER_ELEM,
325 WASM_SEC_ORDER_DATACOUNT,
326 WASM_SEC_ORDER_CODE,
327 WASM_SEC_ORDER_DATA,
328
329 // Custom sections
330 // "dylink" should be the very first section in the module
331 WASM_SEC_ORDER_DYLINK,
332 // "linking" section requires DATA section in order to validate data symbols
333 WASM_SEC_ORDER_LINKING,
334 // Must come after "linking" section in order to validate reloc indexes.
335 WASM_SEC_ORDER_RELOC,
336 // "name" section must appear after DATA. Comes after "linking" to allow
337 // symbol table to set default function name.
338 WASM_SEC_ORDER_NAME,
339 // "producers" section must appear after "name" section.
340 WASM_SEC_ORDER_PRODUCERS,
341 // "target_features" section must appear after producers section
342 WASM_SEC_ORDER_TARGET_FEATURES,
343
344 // Must be last
345 WASM_NUM_SEC_ORDERS
346
347 };
348
349 // Sections that may or may not be present, but cannot be predecessors
350 static int DisallowedPredecessors[WASM_NUM_SEC_ORDERS][WASM_NUM_SEC_ORDERS];
351
352 bool isValidSectionOrder(unsigned ID, StringRef CustomSectionName = "");
353
354private:
355 bool Seen[WASM_NUM_SEC_ORDERS] = {}; // Sections that have been seen already
356
357 // Returns -1 for unknown sections.
358 int getSectionOrder(unsigned ID, StringRef CustomSectionName = "");
359};
360
361} // end namespace object
362
363inline raw_ostream &operator<<(raw_ostream &OS, const object::WasmSymbol &Sym) {
364 Sym.print(OS);
365 return OS;
366}
367
368} // end namespace llvm
369
370#endif // LLVM_OBJECT_WASM_H
371