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llvm-mirror/lib/ObjectYAML/WasmEmitter.cpp
Richard Smith 6da2ed6abd Diagnose if a SLEB128 is too large to fit in an int64_t.
Previously we'd hit UB due to an invalid left shift operand.

Also fix the WASM emitter to properly use SLEB128 encoding instead of
ULEB128 encoding for signed fields so that negative numbers don't
result in overly-large values that we can't read back any more.

In passing, don't diagnose a non-canonical ULEB128 that fits in a uint64_t but
has redundant trailing zero bytes.

Reviewed By: dblaikie, aardappel

Differential Revision: https://reviews.llvm.org/D95510
2021-02-02 14:33:34 -08:00

674 lines
23 KiB
C++

//===- yaml2wasm - Convert YAML to a Wasm object file --------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// The Wasm component of yaml2obj.
///
//===----------------------------------------------------------------------===//
//
#include "llvm/Object/Wasm.h"
#include "llvm/ObjectYAML/ObjectYAML.h"
#include "llvm/ObjectYAML/yaml2obj.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/LEB128.h"
using namespace llvm;
namespace {
/// This parses a yaml stream that represents a Wasm object file.
/// See docs/yaml2obj for the yaml scheema.
class WasmWriter {
public:
WasmWriter(WasmYAML::Object &Obj, yaml::ErrorHandler EH)
: Obj(Obj), ErrHandler(EH) {}
bool writeWasm(raw_ostream &OS);
private:
void writeRelocSection(raw_ostream &OS, WasmYAML::Section &Sec,
uint32_t SectionIndex);
void writeInitExpr(raw_ostream &OS, const wasm::WasmInitExpr &InitExpr);
void writeSectionContent(raw_ostream &OS, WasmYAML::CustomSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::TypeSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::ImportSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::FunctionSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::TableSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::MemorySection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::EventSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::GlobalSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::ExportSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::StartSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::ElemSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::CodeSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::DataSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::DataCountSection &Section);
// Custom section types
void writeSectionContent(raw_ostream &OS, WasmYAML::DylinkSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::NameSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::LinkingSection &Section);
void writeSectionContent(raw_ostream &OS, WasmYAML::ProducersSection &Section);
void writeSectionContent(raw_ostream &OS,
WasmYAML::TargetFeaturesSection &Section);
WasmYAML::Object &Obj;
uint32_t NumImportedFunctions = 0;
uint32_t NumImportedGlobals = 0;
uint32_t NumImportedTables = 0;
uint32_t NumImportedEvents = 0;
bool HasError = false;
yaml::ErrorHandler ErrHandler;
void reportError(const Twine &Msg);
};
class SubSectionWriter {
raw_ostream &OS;
std::string OutString;
raw_string_ostream StringStream;
public:
SubSectionWriter(raw_ostream &OS) : OS(OS), StringStream(OutString) {}
void done() {
StringStream.flush();
encodeULEB128(OutString.size(), OS);
OS << OutString;
OutString.clear();
}
raw_ostream &getStream() { return StringStream; }
};
} // end anonymous namespace
static int writeUint64(raw_ostream &OS, uint64_t Value) {
char Data[sizeof(Value)];
support::endian::write64le(Data, Value);
OS.write(Data, sizeof(Data));
return 0;
}
static int writeUint32(raw_ostream &OS, uint32_t Value) {
char Data[sizeof(Value)];
support::endian::write32le(Data, Value);
OS.write(Data, sizeof(Data));
return 0;
}
static int writeUint8(raw_ostream &OS, uint8_t Value) {
char Data[sizeof(Value)];
memcpy(Data, &Value, sizeof(Data));
OS.write(Data, sizeof(Data));
return 0;
}
static int writeStringRef(const StringRef &Str, raw_ostream &OS) {
encodeULEB128(Str.size(), OS);
OS << Str;
return 0;
}
static int writeLimits(const WasmYAML::Limits &Lim, raw_ostream &OS) {
writeUint8(OS, Lim.Flags);
encodeULEB128(Lim.Initial, OS);
if (Lim.Flags & wasm::WASM_LIMITS_FLAG_HAS_MAX)
encodeULEB128(Lim.Maximum, OS);
return 0;
}
void WasmWriter::reportError(const Twine &Msg) {
ErrHandler(Msg);
HasError = true;
}
void WasmWriter::writeInitExpr(raw_ostream &OS,
const wasm::WasmInitExpr &InitExpr) {
writeUint8(OS, InitExpr.Opcode);
switch (InitExpr.Opcode) {
case wasm::WASM_OPCODE_I32_CONST:
encodeSLEB128(InitExpr.Value.Int32, OS);
break;
case wasm::WASM_OPCODE_I64_CONST:
encodeSLEB128(InitExpr.Value.Int64, OS);
break;
case wasm::WASM_OPCODE_F32_CONST:
writeUint32(OS, InitExpr.Value.Float32);
break;
case wasm::WASM_OPCODE_F64_CONST:
writeUint64(OS, InitExpr.Value.Float64);
break;
case wasm::WASM_OPCODE_GLOBAL_GET:
encodeULEB128(InitExpr.Value.Global, OS);
break;
default:
reportError("unknown opcode in init_expr: " + Twine(InitExpr.Opcode));
return;
}
writeUint8(OS, wasm::WASM_OPCODE_END);
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::DylinkSection &Section) {
writeStringRef(Section.Name, OS);
encodeULEB128(Section.MemorySize, OS);
encodeULEB128(Section.MemoryAlignment, OS);
encodeULEB128(Section.TableSize, OS);
encodeULEB128(Section.TableAlignment, OS);
encodeULEB128(Section.Needed.size(), OS);
for (StringRef Needed : Section.Needed)
writeStringRef(Needed, OS);
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::LinkingSection &Section) {
writeStringRef(Section.Name, OS);
encodeULEB128(Section.Version, OS);
SubSectionWriter SubSection(OS);
// SYMBOL_TABLE subsection
if (Section.SymbolTable.size()) {
writeUint8(OS, wasm::WASM_SYMBOL_TABLE);
encodeULEB128(Section.SymbolTable.size(), SubSection.getStream());
#ifndef NDEBUG
uint32_t SymbolIndex = 0;
#endif
for (const WasmYAML::SymbolInfo &Info : Section.SymbolTable) {
assert(Info.Index == SymbolIndex++);
writeUint8(SubSection.getStream(), Info.Kind);
encodeULEB128(Info.Flags, SubSection.getStream());
switch (Info.Kind) {
case wasm::WASM_SYMBOL_TYPE_FUNCTION:
case wasm::WASM_SYMBOL_TYPE_GLOBAL:
case wasm::WASM_SYMBOL_TYPE_TABLE:
case wasm::WASM_SYMBOL_TYPE_EVENT:
encodeULEB128(Info.ElementIndex, SubSection.getStream());
if ((Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0 ||
(Info.Flags & wasm::WASM_SYMBOL_EXPLICIT_NAME) != 0)
writeStringRef(Info.Name, SubSection.getStream());
break;
case wasm::WASM_SYMBOL_TYPE_DATA:
writeStringRef(Info.Name, SubSection.getStream());
if ((Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0) {
encodeULEB128(Info.DataRef.Segment, SubSection.getStream());
encodeULEB128(Info.DataRef.Offset, SubSection.getStream());
encodeULEB128(Info.DataRef.Size, SubSection.getStream());
}
break;
case wasm::WASM_SYMBOL_TYPE_SECTION:
encodeULEB128(Info.ElementIndex, SubSection.getStream());
break;
default:
llvm_unreachable("unexpected kind");
}
}
SubSection.done();
}
// SEGMENT_NAMES subsection
if (Section.SegmentInfos.size()) {
writeUint8(OS, wasm::WASM_SEGMENT_INFO);
encodeULEB128(Section.SegmentInfos.size(), SubSection.getStream());
for (const WasmYAML::SegmentInfo &SegmentInfo : Section.SegmentInfos) {
writeStringRef(SegmentInfo.Name, SubSection.getStream());
encodeULEB128(SegmentInfo.Alignment, SubSection.getStream());
encodeULEB128(SegmentInfo.Flags, SubSection.getStream());
}
SubSection.done();
}
// INIT_FUNCS subsection
if (Section.InitFunctions.size()) {
writeUint8(OS, wasm::WASM_INIT_FUNCS);
encodeULEB128(Section.InitFunctions.size(), SubSection.getStream());
for (const WasmYAML::InitFunction &Func : Section.InitFunctions) {
encodeULEB128(Func.Priority, SubSection.getStream());
encodeULEB128(Func.Symbol, SubSection.getStream());
}
SubSection.done();
}
// COMDAT_INFO subsection
if (Section.Comdats.size()) {
writeUint8(OS, wasm::WASM_COMDAT_INFO);
encodeULEB128(Section.Comdats.size(), SubSection.getStream());
for (const auto &C : Section.Comdats) {
writeStringRef(C.Name, SubSection.getStream());
encodeULEB128(0, SubSection.getStream()); // flags for future use
encodeULEB128(C.Entries.size(), SubSection.getStream());
for (const WasmYAML::ComdatEntry &Entry : C.Entries) {
writeUint8(SubSection.getStream(), Entry.Kind);
encodeULEB128(Entry.Index, SubSection.getStream());
}
}
SubSection.done();
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::NameSection &Section) {
writeStringRef(Section.Name, OS);
if (Section.FunctionNames.size()) {
writeUint8(OS, wasm::WASM_NAMES_FUNCTION);
SubSectionWriter SubSection(OS);
encodeULEB128(Section.FunctionNames.size(), SubSection.getStream());
for (const WasmYAML::NameEntry &NameEntry : Section.FunctionNames) {
encodeULEB128(NameEntry.Index, SubSection.getStream());
writeStringRef(NameEntry.Name, SubSection.getStream());
}
SubSection.done();
}
if (Section.GlobalNames.size()) {
writeUint8(OS, wasm::WASM_NAMES_GLOBAL);
SubSectionWriter SubSection(OS);
encodeULEB128(Section.GlobalNames.size(), SubSection.getStream());
for (const WasmYAML::NameEntry &NameEntry : Section.GlobalNames) {
encodeULEB128(NameEntry.Index, SubSection.getStream());
writeStringRef(NameEntry.Name, SubSection.getStream());
}
SubSection.done();
}
if (Section.DataSegmentNames.size()) {
writeUint8(OS, wasm::WASM_NAMES_DATA_SEGMENT);
SubSectionWriter SubSection(OS);
encodeULEB128(Section.DataSegmentNames.size(), SubSection.getStream());
for (const WasmYAML::NameEntry &NameEntry : Section.DataSegmentNames) {
encodeULEB128(NameEntry.Index, SubSection.getStream());
writeStringRef(NameEntry.Name, SubSection.getStream());
}
SubSection.done();
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::ProducersSection &Section) {
writeStringRef(Section.Name, OS);
int Fields = int(!Section.Languages.empty()) + int(!Section.Tools.empty()) +
int(!Section.SDKs.empty());
if (Fields == 0)
return;
encodeULEB128(Fields, OS);
for (auto &Field : {std::make_pair(StringRef("language"), &Section.Languages),
std::make_pair(StringRef("processed-by"), &Section.Tools),
std::make_pair(StringRef("sdk"), &Section.SDKs)}) {
if (Field.second->empty())
continue;
writeStringRef(Field.first, OS);
encodeULEB128(Field.second->size(), OS);
for (auto &Entry : *Field.second) {
writeStringRef(Entry.Name, OS);
writeStringRef(Entry.Version, OS);
}
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::TargetFeaturesSection &Section) {
writeStringRef(Section.Name, OS);
encodeULEB128(Section.Features.size(), OS);
for (auto &E : Section.Features) {
writeUint8(OS, E.Prefix);
writeStringRef(E.Name, OS);
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::CustomSection &Section) {
if (auto S = dyn_cast<WasmYAML::DylinkSection>(&Section)) {
writeSectionContent(OS, *S);
} else if (auto S = dyn_cast<WasmYAML::NameSection>(&Section)) {
writeSectionContent(OS, *S);
} else if (auto S = dyn_cast<WasmYAML::LinkingSection>(&Section)) {
writeSectionContent(OS, *S);
} else if (auto S = dyn_cast<WasmYAML::ProducersSection>(&Section)) {
writeSectionContent(OS, *S);
} else if (auto S = dyn_cast<WasmYAML::TargetFeaturesSection>(&Section)) {
writeSectionContent(OS, *S);
} else {
writeStringRef(Section.Name, OS);
Section.Payload.writeAsBinary(OS);
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::TypeSection &Section) {
encodeULEB128(Section.Signatures.size(), OS);
uint32_t ExpectedIndex = 0;
for (const WasmYAML::Signature &Sig : Section.Signatures) {
if (Sig.Index != ExpectedIndex) {
reportError("unexpected type index: " + Twine(Sig.Index));
return;
}
++ExpectedIndex;
writeUint8(OS, Sig.Form);
encodeULEB128(Sig.ParamTypes.size(), OS);
for (auto ParamType : Sig.ParamTypes)
writeUint8(OS, ParamType);
encodeULEB128(Sig.ReturnTypes.size(), OS);
for (auto ReturnType : Sig.ReturnTypes)
writeUint8(OS, ReturnType);
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::ImportSection &Section) {
encodeULEB128(Section.Imports.size(), OS);
for (const WasmYAML::Import &Import : Section.Imports) {
writeStringRef(Import.Module, OS);
writeStringRef(Import.Field, OS);
writeUint8(OS, Import.Kind);
switch (Import.Kind) {
case wasm::WASM_EXTERNAL_FUNCTION:
encodeULEB128(Import.SigIndex, OS);
NumImportedFunctions++;
break;
case wasm::WASM_EXTERNAL_GLOBAL:
writeUint8(OS, Import.GlobalImport.Type);
writeUint8(OS, Import.GlobalImport.Mutable);
NumImportedGlobals++;
break;
case wasm::WASM_EXTERNAL_EVENT:
writeUint32(OS, Import.EventImport.Attribute);
writeUint32(OS, Import.EventImport.SigIndex);
NumImportedEvents++;
break;
case wasm::WASM_EXTERNAL_MEMORY:
writeLimits(Import.Memory, OS);
break;
case wasm::WASM_EXTERNAL_TABLE:
writeUint8(OS, Import.TableImport.ElemType);
writeLimits(Import.TableImport.TableLimits, OS);
NumImportedTables++;
break;
default:
reportError("unknown import type: " +Twine(Import.Kind));
return;
}
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::FunctionSection &Section) {
encodeULEB128(Section.FunctionTypes.size(), OS);
for (uint32_t FuncType : Section.FunctionTypes)
encodeULEB128(FuncType, OS);
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::ExportSection &Section) {
encodeULEB128(Section.Exports.size(), OS);
for (const WasmYAML::Export &Export : Section.Exports) {
writeStringRef(Export.Name, OS);
writeUint8(OS, Export.Kind);
encodeULEB128(Export.Index, OS);
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::StartSection &Section) {
encodeULEB128(Section.StartFunction, OS);
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::TableSection &Section) {
encodeULEB128(Section.Tables.size(), OS);
uint32_t ExpectedIndex = NumImportedTables;
for (auto &Table : Section.Tables) {
if (Table.Index != ExpectedIndex) {
reportError("unexpected table index: " + Twine(Table.Index));
return;
}
++ExpectedIndex;
writeUint8(OS, Table.ElemType);
writeLimits(Table.TableLimits, OS);
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::MemorySection &Section) {
encodeULEB128(Section.Memories.size(), OS);
for (const WasmYAML::Limits &Mem : Section.Memories)
writeLimits(Mem, OS);
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::EventSection &Section) {
encodeULEB128(Section.Events.size(), OS);
uint32_t ExpectedIndex = NumImportedEvents;
for (auto &Event : Section.Events) {
if (Event.Index != ExpectedIndex) {
reportError("unexpected event index: " + Twine(Event.Index));
return;
}
++ExpectedIndex;
encodeULEB128(Event.Attribute, OS);
encodeULEB128(Event.SigIndex, OS);
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::GlobalSection &Section) {
encodeULEB128(Section.Globals.size(), OS);
uint32_t ExpectedIndex = NumImportedGlobals;
for (auto &Global : Section.Globals) {
if (Global.Index != ExpectedIndex) {
reportError("unexpected global index: " + Twine(Global.Index));
return;
}
++ExpectedIndex;
writeUint8(OS, Global.Type);
writeUint8(OS, Global.Mutable);
writeInitExpr(OS, Global.InitExpr);
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::ElemSection &Section) {
encodeULEB128(Section.Segments.size(), OS);
for (auto &Segment : Section.Segments) {
encodeULEB128(Segment.TableIndex, OS);
writeInitExpr(OS, Segment.Offset);
encodeULEB128(Segment.Functions.size(), OS);
for (auto &Function : Segment.Functions)
encodeULEB128(Function, OS);
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::CodeSection &Section) {
encodeULEB128(Section.Functions.size(), OS);
uint32_t ExpectedIndex = NumImportedFunctions;
for (auto &Func : Section.Functions) {
std::string OutString;
raw_string_ostream StringStream(OutString);
if (Func.Index != ExpectedIndex) {
reportError("unexpected function index: " + Twine(Func.Index));
return;
}
++ExpectedIndex;
encodeULEB128(Func.Locals.size(), StringStream);
for (auto &LocalDecl : Func.Locals) {
encodeULEB128(LocalDecl.Count, StringStream);
writeUint8(StringStream, LocalDecl.Type);
}
Func.Body.writeAsBinary(StringStream);
// Write the section size followed by the content
StringStream.flush();
encodeULEB128(OutString.size(), OS);
OS << OutString;
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::DataSection &Section) {
encodeULEB128(Section.Segments.size(), OS);
for (auto &Segment : Section.Segments) {
encodeULEB128(Segment.InitFlags, OS);
if (Segment.InitFlags & wasm::WASM_DATA_SEGMENT_HAS_MEMINDEX)
encodeULEB128(Segment.MemoryIndex, OS);
if ((Segment.InitFlags & wasm::WASM_DATA_SEGMENT_IS_PASSIVE) == 0)
writeInitExpr(OS, Segment.Offset);
encodeULEB128(Segment.Content.binary_size(), OS);
Segment.Content.writeAsBinary(OS);
}
}
void WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::DataCountSection &Section) {
encodeULEB128(Section.Count, OS);
}
void WasmWriter::writeRelocSection(raw_ostream &OS, WasmYAML::Section &Sec,
uint32_t SectionIndex) {
switch (Sec.Type) {
case wasm::WASM_SEC_CODE:
writeStringRef("reloc.CODE", OS);
break;
case wasm::WASM_SEC_DATA:
writeStringRef("reloc.DATA", OS);
break;
case wasm::WASM_SEC_CUSTOM: {
auto *CustomSection = cast<WasmYAML::CustomSection>(&Sec);
writeStringRef(("reloc." + CustomSection->Name).str(), OS);
break;
}
default:
llvm_unreachable("not yet implemented");
}
encodeULEB128(SectionIndex, OS);
encodeULEB128(Sec.Relocations.size(), OS);
for (auto Reloc : Sec.Relocations) {
writeUint8(OS, Reloc.Type);
encodeULEB128(Reloc.Offset, OS);
encodeULEB128(Reloc.Index, OS);
switch (Reloc.Type) {
case wasm::R_WASM_MEMORY_ADDR_LEB:
case wasm::R_WASM_MEMORY_ADDR_LEB64:
case wasm::R_WASM_MEMORY_ADDR_SLEB:
case wasm::R_WASM_MEMORY_ADDR_SLEB64:
case wasm::R_WASM_MEMORY_ADDR_I32:
case wasm::R_WASM_MEMORY_ADDR_I64:
case wasm::R_WASM_FUNCTION_OFFSET_I32:
case wasm::R_WASM_FUNCTION_OFFSET_I64:
case wasm::R_WASM_SECTION_OFFSET_I32:
encodeSLEB128(Reloc.Addend, OS);
break;
}
}
}
bool WasmWriter::writeWasm(raw_ostream &OS) {
// Write headers
OS.write(wasm::WasmMagic, sizeof(wasm::WasmMagic));
writeUint32(OS, Obj.Header.Version);
// Write each section
llvm::object::WasmSectionOrderChecker Checker;
for (const std::unique_ptr<WasmYAML::Section> &Sec : Obj.Sections) {
StringRef SecName = "";
if (auto S = dyn_cast<WasmYAML::CustomSection>(Sec.get()))
SecName = S->Name;
if (!Checker.isValidSectionOrder(Sec->Type, SecName)) {
reportError("out of order section type: " + Twine(Sec->Type));
return false;
}
encodeULEB128(Sec->Type, OS);
std::string OutString;
raw_string_ostream StringStream(OutString);
if (auto S = dyn_cast<WasmYAML::CustomSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::TypeSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::ImportSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::FunctionSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::TableSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::MemorySection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::EventSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::GlobalSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::ExportSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::StartSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::ElemSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::CodeSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::DataSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else if (auto S = dyn_cast<WasmYAML::DataCountSection>(Sec.get()))
writeSectionContent(StringStream, *S);
else
reportError("unknown section type: " + Twine(Sec->Type));
if (HasError)
return false;
StringStream.flush();
// Write the section size followed by the content
encodeULEB128(OutString.size(), OS);
OS << OutString;
}
// write reloc sections for any section that have relocations
uint32_t SectionIndex = 0;
for (const std::unique_ptr<WasmYAML::Section> &Sec : Obj.Sections) {
if (Sec->Relocations.empty()) {
SectionIndex++;
continue;
}
writeUint8(OS, wasm::WASM_SEC_CUSTOM);
std::string OutString;
raw_string_ostream StringStream(OutString);
writeRelocSection(StringStream, *Sec, SectionIndex++);
StringStream.flush();
encodeULEB128(OutString.size(), OS);
OS << OutString;
}
return true;
}
namespace llvm {
namespace yaml {
bool yaml2wasm(WasmYAML::Object &Doc, raw_ostream &Out, ErrorHandler EH) {
WasmWriter Writer(Doc, EH);
return Writer.writeWasm(Out);
}
} // namespace yaml
} // namespace llvm