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//===- yaml2wasm - Convert YAML to a Wasm object file --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// The Wasm component of yaml2obj.
///
//===----------------------------------------------------------------------===//
//
#include "llvm/ObjectYAML/ObjectYAML.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/LEB128.h"
using namespace llvm;
/// 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) : Obj(Obj) {}
int writeWasm(raw_ostream &OS);
private:
int writeRelocSection(raw_ostream &OS, WasmYAML::Section &Sec,
uint32_t SectionIndex);
int writeSectionContent(raw_ostream &OS, WasmYAML::CustomSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::TypeSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::ImportSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::FunctionSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::TableSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::MemorySection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::GlobalSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::ExportSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::StartSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::ElemSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::CodeSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::DataSection &Section);
// Custom section types
int writeSectionContent(raw_ostream &OS, WasmYAML::NameSection &Section);
int writeSectionContent(raw_ostream &OS, WasmYAML::LinkingSection &Section);
WasmYAML::Object &Obj;
uint32_t NumImportedFunctions = 0;
uint32_t NumImportedGlobals = 0;
};
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;
}
static int writeInitExpr(const wasm::WasmInitExpr &InitExpr, raw_ostream &OS) {
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_GET_GLOBAL:
encodeULEB128(InitExpr.Value.Global, OS);
break;
default:
errs() << "Unknown opcode in init_expr: " << InitExpr.Opcode << "\n";
return 1;
}
writeUint8(OS, wasm::WASM_OPCODE_END);
return 0;
}
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;
}
};
int 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:
encodeULEB128(Info.ElementIndex, SubSection.GetStream());
if ((Info.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 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();
}
return 0;
}
int 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();
}
return 0;
}
int WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::CustomSection &Section) {
if (auto S = dyn_cast<WasmYAML::NameSection>(&Section)) {
if (auto Err = writeSectionContent(OS, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::LinkingSection>(&Section)) {
if (auto Err = writeSectionContent(OS, *S))
return Err;
} else {
writeStringRef(Section.Name, OS);
Section.Payload.writeAsBinary(OS);
}
return 0;
}
int 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) {
errs() << "Unexpected type index: " << Sig.Index << "\n";
return 1;
}
++ExpectedIndex;
writeUint8(OS, Sig.Form);
encodeULEB128(Sig.ParamTypes.size(), OS);
for (auto ParamType : Sig.ParamTypes)
writeUint8(OS, ParamType);
if (Sig.ReturnType == wasm::WASM_TYPE_NORESULT) {
encodeULEB128(0, OS);
} else {
encodeULEB128(1, OS);
writeUint8(OS, Sig.ReturnType);
}
}
return 0;
}
int 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_MEMORY:
writeLimits(Import.Memory, OS);
break;
case wasm::WASM_EXTERNAL_TABLE:
writeUint8(OS,Import.TableImport.ElemType);
writeLimits(Import.TableImport.TableLimits, OS);
break;
default:
errs() << "Unknown import type: " << Import.Kind << "\n";
return 1;
}
}
return 0;
}
int WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::FunctionSection &Section) {
encodeULEB128(Section.FunctionTypes.size(), OS);
for (uint32_t FuncType : Section.FunctionTypes) {
encodeULEB128(FuncType, OS);
}
return 0;
}
int 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);
}
return 0;
}
int WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::StartSection &Section) {
encodeULEB128(Section.StartFunction, OS);
return 0;
}
int WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::TableSection &Section) {
encodeULEB128(Section.Tables.size(), OS);
for (auto &Table : Section.Tables) {
writeUint8(OS, Table.ElemType);
writeLimits(Table.TableLimits, OS);
}
return 0;
}
int WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::MemorySection &Section) {
encodeULEB128(Section.Memories.size(), OS);
for (const WasmYAML::Limits &Mem : Section.Memories) {
writeLimits(Mem, OS);
}
return 0;
}
int 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) {
errs() << "Unexpected global index: " << Global.Index << "\n";
return 1;
}
++ExpectedIndex;
writeUint8(OS, Global.Type);
writeUint8(OS, Global.Mutable);
writeInitExpr(Global.InitExpr, OS);
}
return 0;
}
int WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::ElemSection &Section) {
encodeULEB128(Section.Segments.size(), OS);
for (auto &Segment : Section.Segments) {
encodeULEB128(Segment.TableIndex, OS);
writeInitExpr(Segment.Offset, OS);
encodeULEB128(Segment.Functions.size(), OS);
for (auto &Function : Segment.Functions) {
encodeULEB128(Function, OS);
}
}
return 0;
}
int 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) {
errs() << "Unexpected function index: " << Func.Index << "\n";
return 1;
}
++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;
}
return 0;
}
int WasmWriter::writeSectionContent(raw_ostream &OS,
WasmYAML::DataSection &Section) {
encodeULEB128(Section.Segments.size(), OS);
for (auto &Segment : Section.Segments) {
encodeULEB128(Segment.MemoryIndex, OS);
writeInitExpr(Segment.Offset, OS);
encodeULEB128(Segment.Content.binary_size(), OS);
Segment.Content.writeAsBinary(OS);
}
return 0;
}
int 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 = dyn_cast<WasmYAML::CustomSection>(&Sec);
if (!CustomSection->Name.startswith(".debug_")) {
llvm_unreachable("not yet implemented (only for debug sections)");
return 1;
}
writeStringRef(("reloc." + CustomSection->Name).str(), OS);
break;
}
default:
llvm_unreachable("not yet implemented");
return 1;
}
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_WEBASSEMBLY_MEMORY_ADDR_LEB:
case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
case wasm::R_WEBASSEMBLY_FUNCTION_OFFSET_I32:
case wasm::R_WEBASSEMBLY_SECTION_OFFSET_I32:
encodeULEB128(Reloc.Addend, OS);
}
}
return 0;
}
int WasmWriter::writeWasm(raw_ostream &OS) {
// Write headers
OS.write(wasm::WasmMagic, sizeof(wasm::WasmMagic));
writeUint32(OS, Obj.Header.Version);
// Write each section
uint32_t LastType = 0;
for (const std::unique_ptr<WasmYAML::Section> &Sec : Obj.Sections) {
uint32_t Type = Sec->Type;
if (Type != wasm::WASM_SEC_CUSTOM) {
if (Type < LastType) {
errs() << "Out of order section type: " << Type << "\n";
return 1;
}
LastType = Type;
}
encodeULEB128(Sec->Type, OS);
std::string OutString;
raw_string_ostream StringStream(OutString);
if (auto S = dyn_cast<WasmYAML::CustomSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::TypeSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::ImportSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::FunctionSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::TableSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::MemorySection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::GlobalSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::ExportSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::StartSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::ElemSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::CodeSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else if (auto S = dyn_cast<WasmYAML::DataSection>(Sec.get())) {
if (auto Err = writeSectionContent(StringStream, *S))
return Err;
} else {
errs() << "Unknown section type: " << Sec->Type << "\n";
return 1;
}
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 0;
}
int yaml2wasm(llvm::WasmYAML::Object &Doc, raw_ostream &Out) {
WasmWriter Writer(Doc);
return Writer.writeWasm(Out);
}