1 //===- yaml2wasm - Convert YAML to a Wasm object file --------------------===//
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 /// \file
10 /// The Wasm component of yaml2obj.
11 ///
12 //===----------------------------------------------------------------------===//
13 //
14
15 #include "llvm/Object/Wasm.h"
16 #include "llvm/ObjectYAML/ObjectYAML.h"
17 #include "llvm/ObjectYAML/yaml2obj.h"
18 #include "llvm/Support/Endian.h"
19 #include "llvm/Support/LEB128.h"
20
21 using namespace llvm;
22
23 namespace {
24 /// This parses a yaml stream that represents a Wasm object file.
25 /// See docs/yaml2obj for the yaml scheema.
26 class WasmWriter {
27 public:
WasmWriter(WasmYAML::Object & Obj,yaml::ErrorHandler EH)28 WasmWriter(WasmYAML::Object &Obj, yaml::ErrorHandler EH)
29 : Obj(Obj), ErrHandler(EH) {}
30 bool writeWasm(raw_ostream &OS);
31
32 private:
33 void writeRelocSection(raw_ostream &OS, WasmYAML::Section &Sec,
34 uint32_t SectionIndex);
35
36 void writeInitExpr(raw_ostream &OS, const WasmYAML::InitExpr &InitExpr);
37
38 void writeSectionContent(raw_ostream &OS, WasmYAML::CustomSection &Section);
39 void writeSectionContent(raw_ostream &OS, WasmYAML::TypeSection &Section);
40 void writeSectionContent(raw_ostream &OS, WasmYAML::ImportSection &Section);
41 void writeSectionContent(raw_ostream &OS, WasmYAML::FunctionSection &Section);
42 void writeSectionContent(raw_ostream &OS, WasmYAML::TableSection &Section);
43 void writeSectionContent(raw_ostream &OS, WasmYAML::MemorySection &Section);
44 void writeSectionContent(raw_ostream &OS, WasmYAML::TagSection &Section);
45 void writeSectionContent(raw_ostream &OS, WasmYAML::GlobalSection &Section);
46 void writeSectionContent(raw_ostream &OS, WasmYAML::ExportSection &Section);
47 void writeSectionContent(raw_ostream &OS, WasmYAML::StartSection &Section);
48 void writeSectionContent(raw_ostream &OS, WasmYAML::ElemSection &Section);
49 void writeSectionContent(raw_ostream &OS, WasmYAML::CodeSection &Section);
50 void writeSectionContent(raw_ostream &OS, WasmYAML::DataSection &Section);
51 void writeSectionContent(raw_ostream &OS, WasmYAML::DataCountSection &Section);
52
53 // Custom section types
54 void writeSectionContent(raw_ostream &OS, WasmYAML::DylinkSection &Section);
55 void writeSectionContent(raw_ostream &OS, WasmYAML::NameSection &Section);
56 void writeSectionContent(raw_ostream &OS, WasmYAML::LinkingSection &Section);
57 void writeSectionContent(raw_ostream &OS, WasmYAML::ProducersSection &Section);
58 void writeSectionContent(raw_ostream &OS,
59 WasmYAML::TargetFeaturesSection &Section);
60 WasmYAML::Object &Obj;
61 uint32_t NumImportedFunctions = 0;
62 uint32_t NumImportedGlobals = 0;
63 uint32_t NumImportedTables = 0;
64 uint32_t NumImportedTags = 0;
65
66 bool HasError = false;
67 yaml::ErrorHandler ErrHandler;
68 void reportError(const Twine &Msg);
69 };
70
71 class SubSectionWriter {
72 raw_ostream &OS;
73 std::string OutString;
74 raw_string_ostream StringStream;
75
76 public:
SubSectionWriter(raw_ostream & OS)77 SubSectionWriter(raw_ostream &OS) : OS(OS), StringStream(OutString) {}
78
done()79 void done() {
80 StringStream.flush();
81 encodeULEB128(OutString.size(), OS);
82 OS << OutString;
83 OutString.clear();
84 }
85
getStream()86 raw_ostream &getStream() { return StringStream; }
87 };
88
89 } // end anonymous namespace
90
writeUint64(raw_ostream & OS,uint64_t Value)91 static int writeUint64(raw_ostream &OS, uint64_t Value) {
92 char Data[sizeof(Value)];
93 support::endian::write64le(Data, Value);
94 OS.write(Data, sizeof(Data));
95 return 0;
96 }
97
writeUint32(raw_ostream & OS,uint32_t Value)98 static int writeUint32(raw_ostream &OS, uint32_t Value) {
99 char Data[sizeof(Value)];
100 support::endian::write32le(Data, Value);
101 OS.write(Data, sizeof(Data));
102 return 0;
103 }
104
writeUint8(raw_ostream & OS,uint8_t Value)105 static int writeUint8(raw_ostream &OS, uint8_t Value) {
106 char Data[sizeof(Value)];
107 memcpy(Data, &Value, sizeof(Data));
108 OS.write(Data, sizeof(Data));
109 return 0;
110 }
111
writeStringRef(const StringRef & Str,raw_ostream & OS)112 static int writeStringRef(const StringRef &Str, raw_ostream &OS) {
113 encodeULEB128(Str.size(), OS);
114 OS << Str;
115 return 0;
116 }
117
writeLimits(const WasmYAML::Limits & Lim,raw_ostream & OS)118 static int writeLimits(const WasmYAML::Limits &Lim, raw_ostream &OS) {
119 writeUint8(OS, Lim.Flags);
120 encodeULEB128(Lim.Minimum, OS);
121 if (Lim.Flags & wasm::WASM_LIMITS_FLAG_HAS_MAX)
122 encodeULEB128(Lim.Maximum, OS);
123 return 0;
124 }
125
reportError(const Twine & Msg)126 void WasmWriter::reportError(const Twine &Msg) {
127 ErrHandler(Msg);
128 HasError = true;
129 }
130
writeInitExpr(raw_ostream & OS,const WasmYAML::InitExpr & InitExpr)131 void WasmWriter::writeInitExpr(raw_ostream &OS,
132 const WasmYAML::InitExpr &InitExpr) {
133 if (InitExpr.Extended) {
134 InitExpr.Body.writeAsBinary(OS);
135 } else {
136 writeUint8(OS, InitExpr.Inst.Opcode);
137 switch (InitExpr.Inst.Opcode) {
138 case wasm::WASM_OPCODE_I32_CONST:
139 encodeSLEB128(InitExpr.Inst.Value.Int32, OS);
140 break;
141 case wasm::WASM_OPCODE_I64_CONST:
142 encodeSLEB128(InitExpr.Inst.Value.Int64, OS);
143 break;
144 case wasm::WASM_OPCODE_F32_CONST:
145 writeUint32(OS, InitExpr.Inst.Value.Float32);
146 break;
147 case wasm::WASM_OPCODE_F64_CONST:
148 writeUint64(OS, InitExpr.Inst.Value.Float64);
149 break;
150 case wasm::WASM_OPCODE_GLOBAL_GET:
151 encodeULEB128(InitExpr.Inst.Value.Global, OS);
152 break;
153 default:
154 reportError("unknown opcode in init_expr: " +
155 Twine(InitExpr.Inst.Opcode));
156 return;
157 }
158 writeUint8(OS, wasm::WASM_OPCODE_END);
159 }
160 }
161
writeSectionContent(raw_ostream & OS,WasmYAML::DylinkSection & Section)162 void WasmWriter::writeSectionContent(raw_ostream &OS,
163 WasmYAML::DylinkSection &Section) {
164 writeStringRef(Section.Name, OS);
165
166 writeUint8(OS, wasm::WASM_DYLINK_MEM_INFO);
167 SubSectionWriter SubSection(OS);
168 raw_ostream &SubOS = SubSection.getStream();
169 encodeULEB128(Section.MemorySize, SubOS);
170 encodeULEB128(Section.MemoryAlignment, SubOS);
171 encodeULEB128(Section.TableSize, SubOS);
172 encodeULEB128(Section.TableAlignment, SubOS);
173 SubSection.done();
174
175 if (Section.Needed.size()) {
176 writeUint8(OS, wasm::WASM_DYLINK_NEEDED);
177 raw_ostream &SubOS = SubSection.getStream();
178 encodeULEB128(Section.Needed.size(), SubOS);
179 for (StringRef Needed : Section.Needed)
180 writeStringRef(Needed, SubOS);
181 SubSection.done();
182 }
183 }
184
writeSectionContent(raw_ostream & OS,WasmYAML::LinkingSection & Section)185 void WasmWriter::writeSectionContent(raw_ostream &OS,
186 WasmYAML::LinkingSection &Section) {
187 writeStringRef(Section.Name, OS);
188 encodeULEB128(Section.Version, OS);
189
190 SubSectionWriter SubSection(OS);
191
192 // SYMBOL_TABLE subsection
193 if (Section.SymbolTable.size()) {
194 writeUint8(OS, wasm::WASM_SYMBOL_TABLE);
195 encodeULEB128(Section.SymbolTable.size(), SubSection.getStream());
196 for (auto Sym : llvm::enumerate(Section.SymbolTable)) {
197 const WasmYAML::SymbolInfo &Info = Sym.value();
198 assert(Info.Index == Sym.index());
199 writeUint8(SubSection.getStream(), Info.Kind);
200 encodeULEB128(Info.Flags, SubSection.getStream());
201 switch (Info.Kind) {
202 case wasm::WASM_SYMBOL_TYPE_FUNCTION:
203 case wasm::WASM_SYMBOL_TYPE_GLOBAL:
204 case wasm::WASM_SYMBOL_TYPE_TABLE:
205 case wasm::WASM_SYMBOL_TYPE_TAG:
206 encodeULEB128(Info.ElementIndex, SubSection.getStream());
207 if ((Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0 ||
208 (Info.Flags & wasm::WASM_SYMBOL_EXPLICIT_NAME) != 0)
209 writeStringRef(Info.Name, SubSection.getStream());
210 break;
211 case wasm::WASM_SYMBOL_TYPE_DATA:
212 writeStringRef(Info.Name, SubSection.getStream());
213 if ((Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0) {
214 encodeULEB128(Info.DataRef.Segment, SubSection.getStream());
215 encodeULEB128(Info.DataRef.Offset, SubSection.getStream());
216 encodeULEB128(Info.DataRef.Size, SubSection.getStream());
217 }
218 break;
219 case wasm::WASM_SYMBOL_TYPE_SECTION:
220 encodeULEB128(Info.ElementIndex, SubSection.getStream());
221 break;
222 default:
223 llvm_unreachable("unexpected kind");
224 }
225 }
226
227 SubSection.done();
228 }
229
230 // SEGMENT_NAMES subsection
231 if (Section.SegmentInfos.size()) {
232 writeUint8(OS, wasm::WASM_SEGMENT_INFO);
233 encodeULEB128(Section.SegmentInfos.size(), SubSection.getStream());
234 for (const WasmYAML::SegmentInfo &SegmentInfo : Section.SegmentInfos) {
235 writeStringRef(SegmentInfo.Name, SubSection.getStream());
236 encodeULEB128(SegmentInfo.Alignment, SubSection.getStream());
237 encodeULEB128(SegmentInfo.Flags, SubSection.getStream());
238 }
239 SubSection.done();
240 }
241
242 // INIT_FUNCS subsection
243 if (Section.InitFunctions.size()) {
244 writeUint8(OS, wasm::WASM_INIT_FUNCS);
245 encodeULEB128(Section.InitFunctions.size(), SubSection.getStream());
246 for (const WasmYAML::InitFunction &Func : Section.InitFunctions) {
247 encodeULEB128(Func.Priority, SubSection.getStream());
248 encodeULEB128(Func.Symbol, SubSection.getStream());
249 }
250 SubSection.done();
251 }
252
253 // COMDAT_INFO subsection
254 if (Section.Comdats.size()) {
255 writeUint8(OS, wasm::WASM_COMDAT_INFO);
256 encodeULEB128(Section.Comdats.size(), SubSection.getStream());
257 for (const auto &C : Section.Comdats) {
258 writeStringRef(C.Name, SubSection.getStream());
259 encodeULEB128(0, SubSection.getStream()); // flags for future use
260 encodeULEB128(C.Entries.size(), SubSection.getStream());
261 for (const WasmYAML::ComdatEntry &Entry : C.Entries) {
262 writeUint8(SubSection.getStream(), Entry.Kind);
263 encodeULEB128(Entry.Index, SubSection.getStream());
264 }
265 }
266 SubSection.done();
267 }
268 }
269
writeSectionContent(raw_ostream & OS,WasmYAML::NameSection & Section)270 void WasmWriter::writeSectionContent(raw_ostream &OS,
271 WasmYAML::NameSection &Section) {
272 writeStringRef(Section.Name, OS);
273 if (Section.FunctionNames.size()) {
274 writeUint8(OS, wasm::WASM_NAMES_FUNCTION);
275
276 SubSectionWriter SubSection(OS);
277
278 encodeULEB128(Section.FunctionNames.size(), SubSection.getStream());
279 for (const WasmYAML::NameEntry &NameEntry : Section.FunctionNames) {
280 encodeULEB128(NameEntry.Index, SubSection.getStream());
281 writeStringRef(NameEntry.Name, SubSection.getStream());
282 }
283
284 SubSection.done();
285 }
286 if (Section.GlobalNames.size()) {
287 writeUint8(OS, wasm::WASM_NAMES_GLOBAL);
288
289 SubSectionWriter SubSection(OS);
290
291 encodeULEB128(Section.GlobalNames.size(), SubSection.getStream());
292 for (const WasmYAML::NameEntry &NameEntry : Section.GlobalNames) {
293 encodeULEB128(NameEntry.Index, SubSection.getStream());
294 writeStringRef(NameEntry.Name, SubSection.getStream());
295 }
296
297 SubSection.done();
298 }
299 if (Section.DataSegmentNames.size()) {
300 writeUint8(OS, wasm::WASM_NAMES_DATA_SEGMENT);
301
302 SubSectionWriter SubSection(OS);
303
304 encodeULEB128(Section.DataSegmentNames.size(), SubSection.getStream());
305 for (const WasmYAML::NameEntry &NameEntry : Section.DataSegmentNames) {
306 encodeULEB128(NameEntry.Index, SubSection.getStream());
307 writeStringRef(NameEntry.Name, SubSection.getStream());
308 }
309
310 SubSection.done();
311 }
312 }
313
writeSectionContent(raw_ostream & OS,WasmYAML::ProducersSection & Section)314 void WasmWriter::writeSectionContent(raw_ostream &OS,
315 WasmYAML::ProducersSection &Section) {
316 writeStringRef(Section.Name, OS);
317 int Fields = int(!Section.Languages.empty()) + int(!Section.Tools.empty()) +
318 int(!Section.SDKs.empty());
319 if (Fields == 0)
320 return;
321 encodeULEB128(Fields, OS);
322 for (auto &Field : {std::make_pair(StringRef("language"), &Section.Languages),
323 std::make_pair(StringRef("processed-by"), &Section.Tools),
324 std::make_pair(StringRef("sdk"), &Section.SDKs)}) {
325 if (Field.second->empty())
326 continue;
327 writeStringRef(Field.first, OS);
328 encodeULEB128(Field.second->size(), OS);
329 for (auto &Entry : *Field.second) {
330 writeStringRef(Entry.Name, OS);
331 writeStringRef(Entry.Version, OS);
332 }
333 }
334 }
335
writeSectionContent(raw_ostream & OS,WasmYAML::TargetFeaturesSection & Section)336 void WasmWriter::writeSectionContent(raw_ostream &OS,
337 WasmYAML::TargetFeaturesSection &Section) {
338 writeStringRef(Section.Name, OS);
339 encodeULEB128(Section.Features.size(), OS);
340 for (auto &E : Section.Features) {
341 writeUint8(OS, E.Prefix);
342 writeStringRef(E.Name, OS);
343 }
344 }
345
writeSectionContent(raw_ostream & OS,WasmYAML::CustomSection & Section)346 void WasmWriter::writeSectionContent(raw_ostream &OS,
347 WasmYAML::CustomSection &Section) {
348 if (auto S = dyn_cast<WasmYAML::DylinkSection>(&Section)) {
349 writeSectionContent(OS, *S);
350 } else if (auto S = dyn_cast<WasmYAML::NameSection>(&Section)) {
351 writeSectionContent(OS, *S);
352 } else if (auto S = dyn_cast<WasmYAML::LinkingSection>(&Section)) {
353 writeSectionContent(OS, *S);
354 } else if (auto S = dyn_cast<WasmYAML::ProducersSection>(&Section)) {
355 writeSectionContent(OS, *S);
356 } else if (auto S = dyn_cast<WasmYAML::TargetFeaturesSection>(&Section)) {
357 writeSectionContent(OS, *S);
358 } else {
359 writeStringRef(Section.Name, OS);
360 Section.Payload.writeAsBinary(OS);
361 }
362 }
363
writeSectionContent(raw_ostream & OS,WasmYAML::TypeSection & Section)364 void WasmWriter::writeSectionContent(raw_ostream &OS,
365 WasmYAML::TypeSection &Section) {
366 encodeULEB128(Section.Signatures.size(), OS);
367 uint32_t ExpectedIndex = 0;
368 for (const WasmYAML::Signature &Sig : Section.Signatures) {
369 if (Sig.Index != ExpectedIndex) {
370 reportError("unexpected type index: " + Twine(Sig.Index));
371 return;
372 }
373 ++ExpectedIndex;
374 writeUint8(OS, Sig.Form);
375 encodeULEB128(Sig.ParamTypes.size(), OS);
376 for (auto ParamType : Sig.ParamTypes)
377 writeUint8(OS, ParamType);
378 encodeULEB128(Sig.ReturnTypes.size(), OS);
379 for (auto ReturnType : Sig.ReturnTypes)
380 writeUint8(OS, ReturnType);
381 }
382 }
383
writeSectionContent(raw_ostream & OS,WasmYAML::ImportSection & Section)384 void WasmWriter::writeSectionContent(raw_ostream &OS,
385 WasmYAML::ImportSection &Section) {
386 encodeULEB128(Section.Imports.size(), OS);
387 for (const WasmYAML::Import &Import : Section.Imports) {
388 writeStringRef(Import.Module, OS);
389 writeStringRef(Import.Field, OS);
390 writeUint8(OS, Import.Kind);
391 switch (Import.Kind) {
392 case wasm::WASM_EXTERNAL_FUNCTION:
393 encodeULEB128(Import.SigIndex, OS);
394 NumImportedFunctions++;
395 break;
396 case wasm::WASM_EXTERNAL_GLOBAL:
397 writeUint8(OS, Import.GlobalImport.Type);
398 writeUint8(OS, Import.GlobalImport.Mutable);
399 NumImportedGlobals++;
400 break;
401 case wasm::WASM_EXTERNAL_TAG:
402 writeUint8(OS, 0); // Reserved 'attribute' field
403 encodeULEB128(Import.SigIndex, OS);
404 NumImportedTags++;
405 break;
406 case wasm::WASM_EXTERNAL_MEMORY:
407 writeLimits(Import.Memory, OS);
408 break;
409 case wasm::WASM_EXTERNAL_TABLE:
410 writeUint8(OS, Import.TableImport.ElemType);
411 writeLimits(Import.TableImport.TableLimits, OS);
412 NumImportedTables++;
413 break;
414 default:
415 reportError("unknown import type: " +Twine(Import.Kind));
416 return;
417 }
418 }
419 }
420
writeSectionContent(raw_ostream & OS,WasmYAML::FunctionSection & Section)421 void WasmWriter::writeSectionContent(raw_ostream &OS,
422 WasmYAML::FunctionSection &Section) {
423 encodeULEB128(Section.FunctionTypes.size(), OS);
424 for (uint32_t FuncType : Section.FunctionTypes)
425 encodeULEB128(FuncType, OS);
426 }
427
writeSectionContent(raw_ostream & OS,WasmYAML::ExportSection & Section)428 void WasmWriter::writeSectionContent(raw_ostream &OS,
429 WasmYAML::ExportSection &Section) {
430 encodeULEB128(Section.Exports.size(), OS);
431 for (const WasmYAML::Export &Export : Section.Exports) {
432 writeStringRef(Export.Name, OS);
433 writeUint8(OS, Export.Kind);
434 encodeULEB128(Export.Index, OS);
435 }
436 }
437
writeSectionContent(raw_ostream & OS,WasmYAML::StartSection & Section)438 void WasmWriter::writeSectionContent(raw_ostream &OS,
439 WasmYAML::StartSection &Section) {
440 encodeULEB128(Section.StartFunction, OS);
441 }
442
writeSectionContent(raw_ostream & OS,WasmYAML::TableSection & Section)443 void WasmWriter::writeSectionContent(raw_ostream &OS,
444 WasmYAML::TableSection &Section) {
445 encodeULEB128(Section.Tables.size(), OS);
446 uint32_t ExpectedIndex = NumImportedTables;
447 for (auto &Table : Section.Tables) {
448 if (Table.Index != ExpectedIndex) {
449 reportError("unexpected table index: " + Twine(Table.Index));
450 return;
451 }
452 ++ExpectedIndex;
453 writeUint8(OS, Table.ElemType);
454 writeLimits(Table.TableLimits, OS);
455 }
456 }
457
writeSectionContent(raw_ostream & OS,WasmYAML::MemorySection & Section)458 void WasmWriter::writeSectionContent(raw_ostream &OS,
459 WasmYAML::MemorySection &Section) {
460 encodeULEB128(Section.Memories.size(), OS);
461 for (const WasmYAML::Limits &Mem : Section.Memories)
462 writeLimits(Mem, OS);
463 }
464
writeSectionContent(raw_ostream & OS,WasmYAML::TagSection & Section)465 void WasmWriter::writeSectionContent(raw_ostream &OS,
466 WasmYAML::TagSection &Section) {
467 encodeULEB128(Section.TagTypes.size(), OS);
468 for (uint32_t TagType : Section.TagTypes) {
469 writeUint8(OS, 0); // Reserved 'attribute' field
470 encodeULEB128(TagType, OS);
471 }
472 }
473
writeSectionContent(raw_ostream & OS,WasmYAML::GlobalSection & Section)474 void WasmWriter::writeSectionContent(raw_ostream &OS,
475 WasmYAML::GlobalSection &Section) {
476 encodeULEB128(Section.Globals.size(), OS);
477 uint32_t ExpectedIndex = NumImportedGlobals;
478 for (auto &Global : Section.Globals) {
479 if (Global.Index != ExpectedIndex) {
480 reportError("unexpected global index: " + Twine(Global.Index));
481 return;
482 }
483 ++ExpectedIndex;
484 writeUint8(OS, Global.Type);
485 writeUint8(OS, Global.Mutable);
486 writeInitExpr(OS, Global.Init);
487 }
488 }
489
writeSectionContent(raw_ostream & OS,WasmYAML::ElemSection & Section)490 void WasmWriter::writeSectionContent(raw_ostream &OS,
491 WasmYAML::ElemSection &Section) {
492 encodeULEB128(Section.Segments.size(), OS);
493 for (auto &Segment : Section.Segments) {
494 encodeULEB128(Segment.Flags, OS);
495 if (Segment.Flags & wasm::WASM_ELEM_SEGMENT_HAS_TABLE_NUMBER)
496 encodeULEB128(Segment.TableNumber, OS);
497
498 writeInitExpr(OS, Segment.Offset);
499
500 if (Segment.Flags & wasm::WASM_ELEM_SEGMENT_MASK_HAS_ELEM_KIND) {
501 // We only support active function table initializers, for which the elem
502 // kind is specified to be written as 0x00 and interpreted to mean
503 // "funcref".
504 if (Segment.ElemKind != uint32_t(wasm::ValType::FUNCREF)) {
505 reportError("unexpected elemkind: " + Twine(Segment.ElemKind));
506 return;
507 }
508 const uint8_t ElemKind = 0;
509 writeUint8(OS, ElemKind);
510 }
511
512 encodeULEB128(Segment.Functions.size(), OS);
513 for (auto &Function : Segment.Functions)
514 encodeULEB128(Function, OS);
515 }
516 }
517
writeSectionContent(raw_ostream & OS,WasmYAML::CodeSection & Section)518 void WasmWriter::writeSectionContent(raw_ostream &OS,
519 WasmYAML::CodeSection &Section) {
520 encodeULEB128(Section.Functions.size(), OS);
521 uint32_t ExpectedIndex = NumImportedFunctions;
522 for (auto &Func : Section.Functions) {
523 std::string OutString;
524 raw_string_ostream StringStream(OutString);
525 if (Func.Index != ExpectedIndex) {
526 reportError("unexpected function index: " + Twine(Func.Index));
527 return;
528 }
529 ++ExpectedIndex;
530
531 encodeULEB128(Func.Locals.size(), StringStream);
532 for (auto &LocalDecl : Func.Locals) {
533 encodeULEB128(LocalDecl.Count, StringStream);
534 writeUint8(StringStream, LocalDecl.Type);
535 }
536
537 Func.Body.writeAsBinary(StringStream);
538
539 // Write the section size followed by the content
540 StringStream.flush();
541 encodeULEB128(OutString.size(), OS);
542 OS << OutString;
543 }
544 }
545
writeSectionContent(raw_ostream & OS,WasmYAML::DataSection & Section)546 void WasmWriter::writeSectionContent(raw_ostream &OS,
547 WasmYAML::DataSection &Section) {
548 encodeULEB128(Section.Segments.size(), OS);
549 for (auto &Segment : Section.Segments) {
550 encodeULEB128(Segment.InitFlags, OS);
551 if (Segment.InitFlags & wasm::WASM_DATA_SEGMENT_HAS_MEMINDEX)
552 encodeULEB128(Segment.MemoryIndex, OS);
553 if ((Segment.InitFlags & wasm::WASM_DATA_SEGMENT_IS_PASSIVE) == 0)
554 writeInitExpr(OS, Segment.Offset);
555 encodeULEB128(Segment.Content.binary_size(), OS);
556 Segment.Content.writeAsBinary(OS);
557 }
558 }
559
writeSectionContent(raw_ostream & OS,WasmYAML::DataCountSection & Section)560 void WasmWriter::writeSectionContent(raw_ostream &OS,
561 WasmYAML::DataCountSection &Section) {
562 encodeULEB128(Section.Count, OS);
563 }
564
writeRelocSection(raw_ostream & OS,WasmYAML::Section & Sec,uint32_t SectionIndex)565 void WasmWriter::writeRelocSection(raw_ostream &OS, WasmYAML::Section &Sec,
566 uint32_t SectionIndex) {
567 switch (Sec.Type) {
568 case wasm::WASM_SEC_CODE:
569 writeStringRef("reloc.CODE", OS);
570 break;
571 case wasm::WASM_SEC_DATA:
572 writeStringRef("reloc.DATA", OS);
573 break;
574 case wasm::WASM_SEC_CUSTOM: {
575 auto *CustomSection = cast<WasmYAML::CustomSection>(&Sec);
576 writeStringRef(("reloc." + CustomSection->Name).str(), OS);
577 break;
578 }
579 default:
580 llvm_unreachable("not yet implemented");
581 }
582
583 encodeULEB128(SectionIndex, OS);
584 encodeULEB128(Sec.Relocations.size(), OS);
585
586 for (auto Reloc : Sec.Relocations) {
587 writeUint8(OS, Reloc.Type);
588 encodeULEB128(Reloc.Offset, OS);
589 encodeULEB128(Reloc.Index, OS);
590 if (wasm::relocTypeHasAddend(Reloc.Type))
591 encodeSLEB128(Reloc.Addend, OS);
592 }
593 }
594
writeWasm(raw_ostream & OS)595 bool WasmWriter::writeWasm(raw_ostream &OS) {
596 // Write headers
597 OS.write(wasm::WasmMagic, sizeof(wasm::WasmMagic));
598 writeUint32(OS, Obj.Header.Version);
599
600 // Write each section
601 llvm::object::WasmSectionOrderChecker Checker;
602 for (const std::unique_ptr<WasmYAML::Section> &Sec : Obj.Sections) {
603 StringRef SecName = "";
604 if (auto S = dyn_cast<WasmYAML::CustomSection>(Sec.get()))
605 SecName = S->Name;
606 if (!Checker.isValidSectionOrder(Sec->Type, SecName)) {
607 reportError("out of order section type: " + Twine(Sec->Type));
608 return false;
609 }
610 encodeULEB128(Sec->Type, OS);
611 std::string OutString;
612 raw_string_ostream StringStream(OutString);
613 if (auto S = dyn_cast<WasmYAML::CustomSection>(Sec.get()))
614 writeSectionContent(StringStream, *S);
615 else if (auto S = dyn_cast<WasmYAML::TypeSection>(Sec.get()))
616 writeSectionContent(StringStream, *S);
617 else if (auto S = dyn_cast<WasmYAML::ImportSection>(Sec.get()))
618 writeSectionContent(StringStream, *S);
619 else if (auto S = dyn_cast<WasmYAML::FunctionSection>(Sec.get()))
620 writeSectionContent(StringStream, *S);
621 else if (auto S = dyn_cast<WasmYAML::TableSection>(Sec.get()))
622 writeSectionContent(StringStream, *S);
623 else if (auto S = dyn_cast<WasmYAML::MemorySection>(Sec.get()))
624 writeSectionContent(StringStream, *S);
625 else if (auto S = dyn_cast<WasmYAML::TagSection>(Sec.get()))
626 writeSectionContent(StringStream, *S);
627 else if (auto S = dyn_cast<WasmYAML::GlobalSection>(Sec.get()))
628 writeSectionContent(StringStream, *S);
629 else if (auto S = dyn_cast<WasmYAML::ExportSection>(Sec.get()))
630 writeSectionContent(StringStream, *S);
631 else if (auto S = dyn_cast<WasmYAML::StartSection>(Sec.get()))
632 writeSectionContent(StringStream, *S);
633 else if (auto S = dyn_cast<WasmYAML::ElemSection>(Sec.get()))
634 writeSectionContent(StringStream, *S);
635 else if (auto S = dyn_cast<WasmYAML::CodeSection>(Sec.get()))
636 writeSectionContent(StringStream, *S);
637 else if (auto S = dyn_cast<WasmYAML::DataSection>(Sec.get()))
638 writeSectionContent(StringStream, *S);
639 else if (auto S = dyn_cast<WasmYAML::DataCountSection>(Sec.get()))
640 writeSectionContent(StringStream, *S);
641 else
642 reportError("unknown section type: " + Twine(Sec->Type));
643
644 if (HasError)
645 return false;
646
647 StringStream.flush();
648
649 unsigned HeaderSecSizeEncodingLen =
650 Sec->HeaderSecSizeEncodingLen ? *Sec->HeaderSecSizeEncodingLen : 5;
651 unsigned RequiredLen = getULEB128Size(OutString.size());
652 // Wasm spec does not allow LEBs larger than 5 bytes
653 assert(RequiredLen <= 5);
654 if (HeaderSecSizeEncodingLen < RequiredLen) {
655 reportError("section header length can't be encoded in a LEB of size " +
656 Twine(HeaderSecSizeEncodingLen));
657 return false;
658 }
659 // Write the section size followed by the content
660 encodeULEB128(OutString.size(), OS, HeaderSecSizeEncodingLen);
661 OS << OutString;
662 }
663
664 // write reloc sections for any section that have relocations
665 uint32_t SectionIndex = 0;
666 for (const std::unique_ptr<WasmYAML::Section> &Sec : Obj.Sections) {
667 if (Sec->Relocations.empty()) {
668 SectionIndex++;
669 continue;
670 }
671
672 writeUint8(OS, wasm::WASM_SEC_CUSTOM);
673 std::string OutString;
674 raw_string_ostream StringStream(OutString);
675 writeRelocSection(StringStream, *Sec, SectionIndex++);
676 StringStream.flush();
677
678 encodeULEB128(OutString.size(), OS);
679 OS << OutString;
680 }
681
682 return true;
683 }
684
685 namespace llvm {
686 namespace yaml {
687
yaml2wasm(WasmYAML::Object & Doc,raw_ostream & Out,ErrorHandler EH)688 bool yaml2wasm(WasmYAML::Object &Doc, raw_ostream &Out, ErrorHandler EH) {
689 WasmWriter Writer(Doc, EH);
690 return Writer.writeWasm(Out);
691 }
692
693 } // namespace yaml
694 } // namespace llvm
695