Wasm.h revision 327952 
1//===- WasmObjectFile.h - Wasm object file implementation -------*- 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 declares the WasmObjectFile class, which implements the ObjectFile
11// interface for Wasm files.
12//
13// See: https://github.com/WebAssembly/design/blob/master/BinaryEncoding.md
14//
15//===----------------------------------------------------------------------===//
16
17#ifndef LLVM_OBJECT_WASM_H
18#define LLVM_OBJECT_WASM_H
19
20#include "llvm/ADT/ArrayRef.h"
21#include "llvm/ADT/StringRef.h"
22#include "llvm/ADT/StringMap.h"
23#include "llvm/BinaryFormat/Wasm.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  enum class SymbolType {
38    FUNCTION_IMPORT,
39    FUNCTION_EXPORT,
40    GLOBAL_IMPORT,
41    GLOBAL_EXPORT,
42    DEBUG_FUNCTION_NAME,
43  };
44
45  WasmSymbol(StringRef Name, SymbolType Type, uint32_t Section,
46             uint32_t ElementIndex, uint32_t FunctionType = 0)
47      : Name(Name), Type(Type), Section(Section), ElementIndex(ElementIndex),
48        FunctionType(FunctionType) {}
49
50  StringRef Name;
51  SymbolType Type;
52  uint32_t Section;
53  uint32_t Flags = 0;
54
55  // Index into either the function or global index space.
56  uint32_t ElementIndex;
57
58  // For function, the type index
59  uint32_t FunctionType;
60
61  // Symbols can be both exported and imported (in the case of the weakly
62  // defined symbol).  In this the import index is stored as AltIndex.
63  uint32_t AltIndex = 0;
64  bool HasAltIndex = false;
65
66  void setAltIndex(uint32_t Index) {
67    HasAltIndex = true;
68    AltIndex = Index;
69  }
70
71  bool isFunction() const {
72    return Type == WasmSymbol::SymbolType::FUNCTION_IMPORT ||
73           Type == WasmSymbol::SymbolType::FUNCTION_EXPORT ||
74           Type == WasmSymbol::SymbolType::DEBUG_FUNCTION_NAME;
75  }
76
77
78  bool isWeak() const {
79    return getBinding() == wasm::WASM_SYMBOL_BINDING_WEAK;
80  }
81
82  bool isGlobal() const {
83    return getBinding() == wasm::WASM_SYMBOL_BINDING_GLOBAL;
84  }
85
86  bool isLocal() const {
87    return getBinding() == wasm::WASM_SYMBOL_BINDING_LOCAL;
88  }
89
90  unsigned getBinding() const {
91    return Flags & wasm::WASM_SYMBOL_BINDING_MASK;
92  }
93
94  bool isHidden() const {
95    return getVisibility() == wasm::WASM_SYMBOL_VISIBILITY_HIDDEN;
96  }
97
98  unsigned getVisibility() const {
99    return Flags & wasm::WASM_SYMBOL_VISIBILITY_MASK;
100  }
101
102  void print(raw_ostream &Out) const {
103    Out << "Name=" << Name << ", Type=" << static_cast<int>(Type)
104        << ", Flags=" << Flags << " ElemIndex=" << ElementIndex;
105  }
106
107#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
108  LLVM_DUMP_METHOD void dump() const { print(dbgs()); }
109#endif
110};
111
112struct WasmSection {
113  WasmSection() = default;
114
115  uint32_t Type = 0; // Section type (See below)
116  uint32_t Offset = 0; // Offset with in the file
117  StringRef Name; // Section name (User-defined sections only)
118  ArrayRef<uint8_t> Content; // Section content
119  std::vector<wasm::WasmRelocation> Relocations; // Relocations for this section
120};
121
122struct WasmSegment {
123  uint32_t SectionOffset;
124  wasm::WasmDataSegment Data;
125};
126
127class WasmObjectFile : public ObjectFile {
128
129public:
130  WasmObjectFile(MemoryBufferRef Object, Error &Err);
131
132  const wasm::WasmObjectHeader &getHeader() const;
133  const WasmSymbol &getWasmSymbol(const DataRefImpl &Symb) const;
134  const WasmSymbol &getWasmSymbol(const SymbolRef &Symbol) const;
135  const WasmSection &getWasmSection(const SectionRef &Section) const;
136  const wasm::WasmRelocation &getWasmRelocation(const RelocationRef& Ref) const;
137
138  static bool classof(const Binary *v) { return v->isWasm(); }
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::WasmExport> exports() const { return Exports; }
147  const wasm::WasmLinkingData& linkingData() const { return LinkingData; }
148  uint32_t getNumberOfSymbols() const { return Symbols.size(); }
149  ArrayRef<wasm::WasmElemSegment> elements() const { return ElemSegments; }
150  ArrayRef<WasmSegment> dataSegments() const { return DataSegments; }
151  ArrayRef<wasm::WasmFunction> functions() const { return Functions; }
152  uint32_t startFunction() const { return StartFunction; }
153
154  void moveSymbolNext(DataRefImpl &Symb) const override;
155
156  uint32_t getSymbolFlags(DataRefImpl Symb) const override;
157
158  basic_symbol_iterator symbol_begin() const override;
159
160  basic_symbol_iterator symbol_end() const override;
161  Expected<StringRef> getSymbolName(DataRefImpl Symb) const override;
162
163  Expected<uint64_t> getSymbolAddress(DataRefImpl Symb) const override;
164  uint64_t getWasmSymbolValue(const WasmSymbol& Sym) const;
165  uint64_t getSymbolValueImpl(DataRefImpl Symb) const override;
166  uint32_t getSymbolAlignment(DataRefImpl Symb) const override;
167  uint64_t getCommonSymbolSizeImpl(DataRefImpl Symb) const override;
168  Expected<SymbolRef::Type> getSymbolType(DataRefImpl Symb) const override;
169  Expected<section_iterator> getSymbolSection(DataRefImpl Symb) const override;
170
171  // Overrides from SectionRef.
172  void moveSectionNext(DataRefImpl &Sec) const override;
173  std::error_code getSectionName(DataRefImpl Sec,
174                                 StringRef &Res) const override;
175  uint64_t getSectionAddress(DataRefImpl Sec) const override;
176  uint64_t getSectionIndex(DataRefImpl Sec) const override;
177  uint64_t getSectionSize(DataRefImpl Sec) const override;
178  std::error_code getSectionContents(DataRefImpl Sec,
179                                     StringRef &Res) const override;
180  uint64_t getSectionAlignment(DataRefImpl Sec) const override;
181  bool isSectionCompressed(DataRefImpl Sec) const override;
182  bool isSectionText(DataRefImpl Sec) const override;
183  bool isSectionData(DataRefImpl Sec) const override;
184  bool isSectionBSS(DataRefImpl Sec) const override;
185  bool isSectionVirtual(DataRefImpl Sec) const override;
186  bool isSectionBitcode(DataRefImpl Sec) const override;
187  relocation_iterator section_rel_begin(DataRefImpl Sec) const override;
188  relocation_iterator section_rel_end(DataRefImpl Sec) const override;
189
190  // Overrides from RelocationRef.
191  void moveRelocationNext(DataRefImpl &Rel) const override;
192  uint64_t getRelocationOffset(DataRefImpl Rel) const override;
193  symbol_iterator getRelocationSymbol(DataRefImpl Rel) const override;
194  uint64_t getRelocationType(DataRefImpl Rel) const override;
195  void getRelocationTypeName(DataRefImpl Rel,
196                             SmallVectorImpl<char> &Result) const override;
197
198  section_iterator section_begin() const override;
199  section_iterator section_end() const override;
200  uint8_t getBytesInAddress() const override;
201  StringRef getFileFormatName() const override;
202  Triple::ArchType getArch() const override;
203  SubtargetFeatures getFeatures() const override;
204  bool isRelocatableObject() const override;
205
206private:
207  bool isValidFunctionIndex(uint32_t Index) const;
208  const WasmSection &getWasmSection(DataRefImpl Ref) const;
209  const wasm::WasmRelocation &getWasmRelocation(DataRefImpl Ref) const;
210
211  WasmSection* findCustomSectionByName(StringRef Name);
212  WasmSection* findSectionByType(uint32_t Type);
213
214  const uint8_t *getPtr(size_t Offset) const;
215  Error parseSection(WasmSection &Sec);
216  Error parseCustomSection(WasmSection &Sec, const uint8_t *Ptr,
217                           const uint8_t *End);
218
219  // Standard section types
220  Error parseTypeSection(const uint8_t *Ptr, const uint8_t *End);
221  Error parseImportSection(const uint8_t *Ptr, const uint8_t *End);
222  Error parseFunctionSection(const uint8_t *Ptr, const uint8_t *End);
223  Error parseTableSection(const uint8_t *Ptr, const uint8_t *End);
224  Error parseMemorySection(const uint8_t *Ptr, const uint8_t *End);
225  Error parseGlobalSection(const uint8_t *Ptr, const uint8_t *End);
226  Error parseExportSection(const uint8_t *Ptr, const uint8_t *End);
227  Error parseStartSection(const uint8_t *Ptr, const uint8_t *End);
228  Error parseElemSection(const uint8_t *Ptr, const uint8_t *End);
229  Error parseCodeSection(const uint8_t *Ptr, const uint8_t *End);
230  Error parseDataSection(const uint8_t *Ptr, const uint8_t *End);
231
232  // Custom section types
233  Error parseNameSection(const uint8_t *Ptr, const uint8_t *End);
234  Error parseLinkingSection(const uint8_t *Ptr, const uint8_t *End);
235  Error parseRelocSection(StringRef Name, const uint8_t *Ptr,
236                          const uint8_t *End);
237
238  void populateSymbolTable();
239
240  wasm::WasmObjectHeader Header;
241  std::vector<WasmSection> Sections;
242  std::vector<wasm::WasmSignature> Signatures;
243  std::vector<uint32_t> FunctionTypes;
244  std::vector<wasm::WasmTable> Tables;
245  std::vector<wasm::WasmLimits> Memories;
246  std::vector<wasm::WasmGlobal> Globals;
247  std::vector<wasm::WasmImport> Imports;
248  std::vector<wasm::WasmExport> Exports;
249  std::vector<wasm::WasmElemSegment> ElemSegments;
250  std::vector<WasmSegment> DataSegments;
251  std::vector<wasm::WasmFunction> Functions;
252  std::vector<WasmSymbol> Symbols;
253  uint32_t StartFunction = -1;
254  bool HasLinkingSection = false;
255  wasm::WasmLinkingData LinkingData;
256  uint32_t NumImportedGlobals = 0;
257  uint32_t NumImportedFunctions = 0;
258  uint32_t ImportSection = 0;
259  uint32_t ExportSection = 0;
260
261  StringMap<uint32_t> SymbolMap;
262};
263
264} // end namespace object
265
266inline raw_ostream &operator<<(raw_ostream &OS,
267                               const object::WasmSymbol &Sym) {
268  Sym.print(OS);
269  return OS;
270}
271
272} // end namespace llvm
273
274#endif // LLVM_OBJECT_WASM_H
275