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

source code of llvm/lib/ObjectYAML/WasmEmitter.cpp