10b57cec5SDimitry Andric //===- lib/MC/WasmObjectWriter.cpp - Wasm File Writer ---------------------===// 20b57cec5SDimitry Andric // 30b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 40b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 50b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 60b57cec5SDimitry Andric // 70b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 80b57cec5SDimitry Andric // 90b57cec5SDimitry Andric // This file implements Wasm object file writer information. 100b57cec5SDimitry Andric // 110b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 120b57cec5SDimitry Andric 130b57cec5SDimitry Andric #include "llvm/ADT/STLExtras.h" 140b57cec5SDimitry Andric #include "llvm/ADT/SmallPtrSet.h" 150b57cec5SDimitry Andric #include "llvm/BinaryFormat/Wasm.h" 160b57cec5SDimitry Andric #include "llvm/Config/llvm-config.h" 170b57cec5SDimitry Andric #include "llvm/MC/MCAsmBackend.h" 180b57cec5SDimitry Andric #include "llvm/MC/MCAsmLayout.h" 190b57cec5SDimitry Andric #include "llvm/MC/MCAssembler.h" 200b57cec5SDimitry Andric #include "llvm/MC/MCContext.h" 210b57cec5SDimitry Andric #include "llvm/MC/MCExpr.h" 220b57cec5SDimitry Andric #include "llvm/MC/MCFixupKindInfo.h" 230b57cec5SDimitry Andric #include "llvm/MC/MCObjectWriter.h" 240b57cec5SDimitry Andric #include "llvm/MC/MCSectionWasm.h" 250b57cec5SDimitry Andric #include "llvm/MC/MCSymbolWasm.h" 260b57cec5SDimitry Andric #include "llvm/MC/MCValue.h" 270b57cec5SDimitry Andric #include "llvm/MC/MCWasmObjectWriter.h" 280b57cec5SDimitry Andric #include "llvm/Support/Casting.h" 290b57cec5SDimitry Andric #include "llvm/Support/Debug.h" 300b57cec5SDimitry Andric #include "llvm/Support/ErrorHandling.h" 310b57cec5SDimitry Andric #include "llvm/Support/LEB128.h" 320b57cec5SDimitry Andric #include "llvm/Support/StringSaver.h" 330b57cec5SDimitry Andric #include <vector> 340b57cec5SDimitry Andric 350b57cec5SDimitry Andric using namespace llvm; 360b57cec5SDimitry Andric 370b57cec5SDimitry Andric #define DEBUG_TYPE "mc" 380b57cec5SDimitry Andric 390b57cec5SDimitry Andric namespace { 400b57cec5SDimitry Andric 410b57cec5SDimitry Andric // Went we ceate the indirect function table we start at 1, so that there is 420b57cec5SDimitry Andric // and emtpy slot at 0 and therefore calling a null function pointer will trap. 430b57cec5SDimitry Andric static const uint32_t InitialTableOffset = 1; 440b57cec5SDimitry Andric 450b57cec5SDimitry Andric // For patching purposes, we need to remember where each section starts, both 460b57cec5SDimitry Andric // for patching up the section size field, and for patching up references to 470b57cec5SDimitry Andric // locations within the section. 480b57cec5SDimitry Andric struct SectionBookkeeping { 490b57cec5SDimitry Andric // Where the size of the section is written. 500b57cec5SDimitry Andric uint64_t SizeOffset; 510b57cec5SDimitry Andric // Where the section header ends (without custom section name). 520b57cec5SDimitry Andric uint64_t PayloadOffset; 530b57cec5SDimitry Andric // Where the contents of the section starts. 540b57cec5SDimitry Andric uint64_t ContentsOffset; 550b57cec5SDimitry Andric uint32_t Index; 560b57cec5SDimitry Andric }; 570b57cec5SDimitry Andric 580b57cec5SDimitry Andric // The signature of a wasm function or event, in a struct capable of being used 590b57cec5SDimitry Andric // as a DenseMap key. 600b57cec5SDimitry Andric // TODO: Consider using wasm::WasmSignature directly instead. 610b57cec5SDimitry Andric struct WasmSignature { 620b57cec5SDimitry Andric // Support empty and tombstone instances, needed by DenseMap. 630b57cec5SDimitry Andric enum { Plain, Empty, Tombstone } State = Plain; 640b57cec5SDimitry Andric 650b57cec5SDimitry Andric // The return types of the function. 660b57cec5SDimitry Andric SmallVector<wasm::ValType, 1> Returns; 670b57cec5SDimitry Andric 680b57cec5SDimitry Andric // The parameter types of the function. 690b57cec5SDimitry Andric SmallVector<wasm::ValType, 4> Params; 700b57cec5SDimitry Andric 710b57cec5SDimitry Andric bool operator==(const WasmSignature &Other) const { 720b57cec5SDimitry Andric return State == Other.State && Returns == Other.Returns && 730b57cec5SDimitry Andric Params == Other.Params; 740b57cec5SDimitry Andric } 750b57cec5SDimitry Andric }; 760b57cec5SDimitry Andric 770b57cec5SDimitry Andric // Traits for using WasmSignature in a DenseMap. 780b57cec5SDimitry Andric struct WasmSignatureDenseMapInfo { 790b57cec5SDimitry Andric static WasmSignature getEmptyKey() { 800b57cec5SDimitry Andric WasmSignature Sig; 810b57cec5SDimitry Andric Sig.State = WasmSignature::Empty; 820b57cec5SDimitry Andric return Sig; 830b57cec5SDimitry Andric } 840b57cec5SDimitry Andric static WasmSignature getTombstoneKey() { 850b57cec5SDimitry Andric WasmSignature Sig; 860b57cec5SDimitry Andric Sig.State = WasmSignature::Tombstone; 870b57cec5SDimitry Andric return Sig; 880b57cec5SDimitry Andric } 890b57cec5SDimitry Andric static unsigned getHashValue(const WasmSignature &Sig) { 900b57cec5SDimitry Andric uintptr_t Value = Sig.State; 910b57cec5SDimitry Andric for (wasm::ValType Ret : Sig.Returns) 920b57cec5SDimitry Andric Value += DenseMapInfo<uint32_t>::getHashValue(uint32_t(Ret)); 930b57cec5SDimitry Andric for (wasm::ValType Param : Sig.Params) 940b57cec5SDimitry Andric Value += DenseMapInfo<uint32_t>::getHashValue(uint32_t(Param)); 950b57cec5SDimitry Andric return Value; 960b57cec5SDimitry Andric } 970b57cec5SDimitry Andric static bool isEqual(const WasmSignature &LHS, const WasmSignature &RHS) { 980b57cec5SDimitry Andric return LHS == RHS; 990b57cec5SDimitry Andric } 1000b57cec5SDimitry Andric }; 1010b57cec5SDimitry Andric 1020b57cec5SDimitry Andric // A wasm data segment. A wasm binary contains only a single data section 1030b57cec5SDimitry Andric // but that can contain many segments, each with their own virtual location 1040b57cec5SDimitry Andric // in memory. Each MCSection data created by llvm is modeled as its own 1050b57cec5SDimitry Andric // wasm data segment. 1060b57cec5SDimitry Andric struct WasmDataSegment { 1070b57cec5SDimitry Andric MCSectionWasm *Section; 1080b57cec5SDimitry Andric StringRef Name; 1090b57cec5SDimitry Andric uint32_t InitFlags; 1100b57cec5SDimitry Andric uint32_t Offset; 1110b57cec5SDimitry Andric uint32_t Alignment; 1120b57cec5SDimitry Andric uint32_t LinkerFlags; 1130b57cec5SDimitry Andric SmallVector<char, 4> Data; 1140b57cec5SDimitry Andric }; 1150b57cec5SDimitry Andric 1160b57cec5SDimitry Andric // A wasm function to be written into the function section. 1170b57cec5SDimitry Andric struct WasmFunction { 1180b57cec5SDimitry Andric uint32_t SigIndex; 1190b57cec5SDimitry Andric const MCSymbolWasm *Sym; 1200b57cec5SDimitry Andric }; 1210b57cec5SDimitry Andric 1220b57cec5SDimitry Andric // A wasm global to be written into the global section. 1230b57cec5SDimitry Andric struct WasmGlobal { 1240b57cec5SDimitry Andric wasm::WasmGlobalType Type; 1250b57cec5SDimitry Andric uint64_t InitialValue; 1260b57cec5SDimitry Andric }; 1270b57cec5SDimitry Andric 1280b57cec5SDimitry Andric // Information about a single item which is part of a COMDAT. For each data 1290b57cec5SDimitry Andric // segment or function which is in the COMDAT, there is a corresponding 1300b57cec5SDimitry Andric // WasmComdatEntry. 1310b57cec5SDimitry Andric struct WasmComdatEntry { 1320b57cec5SDimitry Andric unsigned Kind; 1330b57cec5SDimitry Andric uint32_t Index; 1340b57cec5SDimitry Andric }; 1350b57cec5SDimitry Andric 1360b57cec5SDimitry Andric // Information about a single relocation. 1370b57cec5SDimitry Andric struct WasmRelocationEntry { 1380b57cec5SDimitry Andric uint64_t Offset; // Where is the relocation. 1390b57cec5SDimitry Andric const MCSymbolWasm *Symbol; // The symbol to relocate with. 1400b57cec5SDimitry Andric int64_t Addend; // A value to add to the symbol. 1410b57cec5SDimitry Andric unsigned Type; // The type of the relocation. 1420b57cec5SDimitry Andric const MCSectionWasm *FixupSection; // The section the relocation is targeting. 1430b57cec5SDimitry Andric 1440b57cec5SDimitry Andric WasmRelocationEntry(uint64_t Offset, const MCSymbolWasm *Symbol, 1450b57cec5SDimitry Andric int64_t Addend, unsigned Type, 1460b57cec5SDimitry Andric const MCSectionWasm *FixupSection) 1470b57cec5SDimitry Andric : Offset(Offset), Symbol(Symbol), Addend(Addend), Type(Type), 1480b57cec5SDimitry Andric FixupSection(FixupSection) {} 1490b57cec5SDimitry Andric 1500b57cec5SDimitry Andric bool hasAddend() const { return wasm::relocTypeHasAddend(Type); } 1510b57cec5SDimitry Andric 1520b57cec5SDimitry Andric void print(raw_ostream &Out) const { 1530b57cec5SDimitry Andric Out << wasm::relocTypetoString(Type) << " Off=" << Offset 1540b57cec5SDimitry Andric << ", Sym=" << *Symbol << ", Addend=" << Addend 1550b57cec5SDimitry Andric << ", FixupSection=" << FixupSection->getSectionName(); 1560b57cec5SDimitry Andric } 1570b57cec5SDimitry Andric 1580b57cec5SDimitry Andric #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 1590b57cec5SDimitry Andric LLVM_DUMP_METHOD void dump() const { print(dbgs()); } 1600b57cec5SDimitry Andric #endif 1610b57cec5SDimitry Andric }; 1620b57cec5SDimitry Andric 1630b57cec5SDimitry Andric static const uint32_t InvalidIndex = -1; 1640b57cec5SDimitry Andric 1650b57cec5SDimitry Andric struct WasmCustomSection { 1660b57cec5SDimitry Andric 1670b57cec5SDimitry Andric StringRef Name; 1680b57cec5SDimitry Andric MCSectionWasm *Section; 1690b57cec5SDimitry Andric 1700b57cec5SDimitry Andric uint32_t OutputContentsOffset; 1710b57cec5SDimitry Andric uint32_t OutputIndex; 1720b57cec5SDimitry Andric 1730b57cec5SDimitry Andric WasmCustomSection(StringRef Name, MCSectionWasm *Section) 1740b57cec5SDimitry Andric : Name(Name), Section(Section), OutputContentsOffset(0), 1750b57cec5SDimitry Andric OutputIndex(InvalidIndex) {} 1760b57cec5SDimitry Andric }; 1770b57cec5SDimitry Andric 1780b57cec5SDimitry Andric #if !defined(NDEBUG) 1790b57cec5SDimitry Andric raw_ostream &operator<<(raw_ostream &OS, const WasmRelocationEntry &Rel) { 1800b57cec5SDimitry Andric Rel.print(OS); 1810b57cec5SDimitry Andric return OS; 1820b57cec5SDimitry Andric } 1830b57cec5SDimitry Andric #endif 1840b57cec5SDimitry Andric 1850b57cec5SDimitry Andric // Write X as an (unsigned) LEB value at offset Offset in Stream, padded 1860b57cec5SDimitry Andric // to allow patching. 1870b57cec5SDimitry Andric static void writePatchableLEB(raw_pwrite_stream &Stream, uint32_t X, 1880b57cec5SDimitry Andric uint64_t Offset) { 1890b57cec5SDimitry Andric uint8_t Buffer[5]; 1900b57cec5SDimitry Andric unsigned SizeLen = encodeULEB128(X, Buffer, 5); 1910b57cec5SDimitry Andric assert(SizeLen == 5); 1920b57cec5SDimitry Andric Stream.pwrite((char *)Buffer, SizeLen, Offset); 1930b57cec5SDimitry Andric } 1940b57cec5SDimitry Andric 1950b57cec5SDimitry Andric // Write X as an signed LEB value at offset Offset in Stream, padded 1960b57cec5SDimitry Andric // to allow patching. 1970b57cec5SDimitry Andric static void writePatchableSLEB(raw_pwrite_stream &Stream, int32_t X, 1980b57cec5SDimitry Andric uint64_t Offset) { 1990b57cec5SDimitry Andric uint8_t Buffer[5]; 2000b57cec5SDimitry Andric unsigned SizeLen = encodeSLEB128(X, Buffer, 5); 2010b57cec5SDimitry Andric assert(SizeLen == 5); 2020b57cec5SDimitry Andric Stream.pwrite((char *)Buffer, SizeLen, Offset); 2030b57cec5SDimitry Andric } 2040b57cec5SDimitry Andric 2050b57cec5SDimitry Andric // Write X as a plain integer value at offset Offset in Stream. 2060b57cec5SDimitry Andric static void writeI32(raw_pwrite_stream &Stream, uint32_t X, uint64_t Offset) { 2070b57cec5SDimitry Andric uint8_t Buffer[4]; 2080b57cec5SDimitry Andric support::endian::write32le(Buffer, X); 2090b57cec5SDimitry Andric Stream.pwrite((char *)Buffer, sizeof(Buffer), Offset); 2100b57cec5SDimitry Andric } 2110b57cec5SDimitry Andric 2120b57cec5SDimitry Andric class WasmObjectWriter : public MCObjectWriter { 2130b57cec5SDimitry Andric support::endian::Writer W; 2140b57cec5SDimitry Andric 2150b57cec5SDimitry Andric /// The target specific Wasm writer instance. 2160b57cec5SDimitry Andric std::unique_ptr<MCWasmObjectTargetWriter> TargetObjectWriter; 2170b57cec5SDimitry Andric 2180b57cec5SDimitry Andric // Relocations for fixing up references in the code section. 2190b57cec5SDimitry Andric std::vector<WasmRelocationEntry> CodeRelocations; 2200b57cec5SDimitry Andric uint32_t CodeSectionIndex; 2210b57cec5SDimitry Andric 2220b57cec5SDimitry Andric // Relocations for fixing up references in the data section. 2230b57cec5SDimitry Andric std::vector<WasmRelocationEntry> DataRelocations; 2240b57cec5SDimitry Andric uint32_t DataSectionIndex; 2250b57cec5SDimitry Andric 2260b57cec5SDimitry Andric // Index values to use for fixing up call_indirect type indices. 2270b57cec5SDimitry Andric // Maps function symbols to the index of the type of the function 2280b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, uint32_t> TypeIndices; 2290b57cec5SDimitry Andric // Maps function symbols to the table element index space. Used 2300b57cec5SDimitry Andric // for TABLE_INDEX relocation types (i.e. address taken functions). 2310b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, uint32_t> TableIndices; 2320b57cec5SDimitry Andric // Maps function/global symbols to the function/global/event/section index 2330b57cec5SDimitry Andric // space. 2340b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, uint32_t> WasmIndices; 2350b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, uint32_t> GOTIndices; 2360b57cec5SDimitry Andric // Maps data symbols to the Wasm segment and offset/size with the segment. 2370b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, wasm::WasmDataReference> DataLocations; 2380b57cec5SDimitry Andric 2390b57cec5SDimitry Andric // Stores output data (index, relocations, content offset) for custom 2400b57cec5SDimitry Andric // section. 2410b57cec5SDimitry Andric std::vector<WasmCustomSection> CustomSections; 2420b57cec5SDimitry Andric std::unique_ptr<WasmCustomSection> ProducersSection; 2430b57cec5SDimitry Andric std::unique_ptr<WasmCustomSection> TargetFeaturesSection; 2440b57cec5SDimitry Andric // Relocations for fixing up references in the custom sections. 2450b57cec5SDimitry Andric DenseMap<const MCSectionWasm *, std::vector<WasmRelocationEntry>> 2460b57cec5SDimitry Andric CustomSectionsRelocations; 2470b57cec5SDimitry Andric 2480b57cec5SDimitry Andric // Map from section to defining function symbol. 2490b57cec5SDimitry Andric DenseMap<const MCSection *, const MCSymbol *> SectionFunctions; 2500b57cec5SDimitry Andric 2510b57cec5SDimitry Andric DenseMap<WasmSignature, uint32_t, WasmSignatureDenseMapInfo> SignatureIndices; 2520b57cec5SDimitry Andric SmallVector<WasmSignature, 4> Signatures; 2530b57cec5SDimitry Andric SmallVector<WasmDataSegment, 4> DataSegments; 2540b57cec5SDimitry Andric unsigned NumFunctionImports = 0; 2550b57cec5SDimitry Andric unsigned NumGlobalImports = 0; 2560b57cec5SDimitry Andric unsigned NumEventImports = 0; 2570b57cec5SDimitry Andric uint32_t SectionCount = 0; 2580b57cec5SDimitry Andric 2590b57cec5SDimitry Andric // TargetObjectWriter wrappers. 2600b57cec5SDimitry Andric bool is64Bit() const { return TargetObjectWriter->is64Bit(); } 2618bcb0991SDimitry Andric bool isEmscripten() const { return TargetObjectWriter->isEmscripten(); } 2620b57cec5SDimitry Andric 2630b57cec5SDimitry Andric void startSection(SectionBookkeeping &Section, unsigned SectionId); 2640b57cec5SDimitry Andric void startCustomSection(SectionBookkeeping &Section, StringRef Name); 2650b57cec5SDimitry Andric void endSection(SectionBookkeeping &Section); 2660b57cec5SDimitry Andric 2670b57cec5SDimitry Andric public: 2680b57cec5SDimitry Andric WasmObjectWriter(std::unique_ptr<MCWasmObjectTargetWriter> MOTW, 2690b57cec5SDimitry Andric raw_pwrite_stream &OS) 2700b57cec5SDimitry Andric : W(OS, support::little), TargetObjectWriter(std::move(MOTW)) {} 2710b57cec5SDimitry Andric 2720b57cec5SDimitry Andric private: 2730b57cec5SDimitry Andric void reset() override { 2740b57cec5SDimitry Andric CodeRelocations.clear(); 2750b57cec5SDimitry Andric DataRelocations.clear(); 2760b57cec5SDimitry Andric TypeIndices.clear(); 2770b57cec5SDimitry Andric WasmIndices.clear(); 2780b57cec5SDimitry Andric GOTIndices.clear(); 2790b57cec5SDimitry Andric TableIndices.clear(); 2800b57cec5SDimitry Andric DataLocations.clear(); 2810b57cec5SDimitry Andric CustomSections.clear(); 2820b57cec5SDimitry Andric ProducersSection.reset(); 2830b57cec5SDimitry Andric TargetFeaturesSection.reset(); 2840b57cec5SDimitry Andric CustomSectionsRelocations.clear(); 2850b57cec5SDimitry Andric SignatureIndices.clear(); 2860b57cec5SDimitry Andric Signatures.clear(); 2870b57cec5SDimitry Andric DataSegments.clear(); 2880b57cec5SDimitry Andric SectionFunctions.clear(); 2890b57cec5SDimitry Andric NumFunctionImports = 0; 2900b57cec5SDimitry Andric NumGlobalImports = 0; 2910b57cec5SDimitry Andric MCObjectWriter::reset(); 2920b57cec5SDimitry Andric } 2930b57cec5SDimitry Andric 2940b57cec5SDimitry Andric void writeHeader(const MCAssembler &Asm); 2950b57cec5SDimitry Andric 2960b57cec5SDimitry Andric void recordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout, 2970b57cec5SDimitry Andric const MCFragment *Fragment, const MCFixup &Fixup, 2980b57cec5SDimitry Andric MCValue Target, uint64_t &FixedValue) override; 2990b57cec5SDimitry Andric 3000b57cec5SDimitry Andric void executePostLayoutBinding(MCAssembler &Asm, 3010b57cec5SDimitry Andric const MCAsmLayout &Layout) override; 3020b57cec5SDimitry Andric 3030b57cec5SDimitry Andric uint64_t writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override; 3040b57cec5SDimitry Andric 3050b57cec5SDimitry Andric void writeString(const StringRef Str) { 3060b57cec5SDimitry Andric encodeULEB128(Str.size(), W.OS); 3070b57cec5SDimitry Andric W.OS << Str; 3080b57cec5SDimitry Andric } 3090b57cec5SDimitry Andric 3100b57cec5SDimitry Andric void writeValueType(wasm::ValType Ty) { W.OS << static_cast<char>(Ty); } 3110b57cec5SDimitry Andric 3120b57cec5SDimitry Andric void writeTypeSection(ArrayRef<WasmSignature> Signatures); 3130b57cec5SDimitry Andric void writeImportSection(ArrayRef<wasm::WasmImport> Imports, uint32_t DataSize, 3140b57cec5SDimitry Andric uint32_t NumElements); 3150b57cec5SDimitry Andric void writeFunctionSection(ArrayRef<WasmFunction> Functions); 3160b57cec5SDimitry Andric void writeExportSection(ArrayRef<wasm::WasmExport> Exports); 3170b57cec5SDimitry Andric void writeElemSection(ArrayRef<uint32_t> TableElems); 3180b57cec5SDimitry Andric void writeDataCountSection(); 3190b57cec5SDimitry Andric void writeCodeSection(const MCAssembler &Asm, const MCAsmLayout &Layout, 3200b57cec5SDimitry Andric ArrayRef<WasmFunction> Functions); 3210b57cec5SDimitry Andric void writeDataSection(); 3220b57cec5SDimitry Andric void writeEventSection(ArrayRef<wasm::WasmEventType> Events); 3230b57cec5SDimitry Andric void writeRelocSection(uint32_t SectionIndex, StringRef Name, 3240b57cec5SDimitry Andric std::vector<WasmRelocationEntry> &Relocations); 3250b57cec5SDimitry Andric void writeLinkingMetaDataSection( 3260b57cec5SDimitry Andric ArrayRef<wasm::WasmSymbolInfo> SymbolInfos, 3270b57cec5SDimitry Andric ArrayRef<std::pair<uint16_t, uint32_t>> InitFuncs, 3280b57cec5SDimitry Andric const std::map<StringRef, std::vector<WasmComdatEntry>> &Comdats); 3290b57cec5SDimitry Andric void writeCustomSection(WasmCustomSection &CustomSection, 3300b57cec5SDimitry Andric const MCAssembler &Asm, const MCAsmLayout &Layout); 3310b57cec5SDimitry Andric void writeCustomRelocSections(); 3320b57cec5SDimitry Andric void 3330b57cec5SDimitry Andric updateCustomSectionRelocations(const SmallVector<WasmFunction, 4> &Functions, 3340b57cec5SDimitry Andric const MCAsmLayout &Layout); 3350b57cec5SDimitry Andric 3360b57cec5SDimitry Andric uint32_t getProvisionalValue(const WasmRelocationEntry &RelEntry); 3370b57cec5SDimitry Andric void applyRelocations(ArrayRef<WasmRelocationEntry> Relocations, 3380b57cec5SDimitry Andric uint64_t ContentsOffset); 3390b57cec5SDimitry Andric 3400b57cec5SDimitry Andric uint32_t getRelocationIndexValue(const WasmRelocationEntry &RelEntry); 3410b57cec5SDimitry Andric uint32_t getFunctionType(const MCSymbolWasm &Symbol); 3420b57cec5SDimitry Andric uint32_t getEventType(const MCSymbolWasm &Symbol); 3430b57cec5SDimitry Andric void registerFunctionType(const MCSymbolWasm &Symbol); 3440b57cec5SDimitry Andric void registerEventType(const MCSymbolWasm &Symbol); 3450b57cec5SDimitry Andric }; 3460b57cec5SDimitry Andric 3470b57cec5SDimitry Andric } // end anonymous namespace 3480b57cec5SDimitry Andric 3490b57cec5SDimitry Andric // Write out a section header and a patchable section size field. 3500b57cec5SDimitry Andric void WasmObjectWriter::startSection(SectionBookkeeping &Section, 3510b57cec5SDimitry Andric unsigned SectionId) { 3520b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "startSection " << SectionId << "\n"); 3530b57cec5SDimitry Andric W.OS << char(SectionId); 3540b57cec5SDimitry Andric 3550b57cec5SDimitry Andric Section.SizeOffset = W.OS.tell(); 3560b57cec5SDimitry Andric 3570b57cec5SDimitry Andric // The section size. We don't know the size yet, so reserve enough space 3580b57cec5SDimitry Andric // for any 32-bit value; we'll patch it later. 3590b57cec5SDimitry Andric encodeULEB128(0, W.OS, 5); 3600b57cec5SDimitry Andric 3610b57cec5SDimitry Andric // The position where the section starts, for measuring its size. 3620b57cec5SDimitry Andric Section.ContentsOffset = W.OS.tell(); 3630b57cec5SDimitry Andric Section.PayloadOffset = W.OS.tell(); 3640b57cec5SDimitry Andric Section.Index = SectionCount++; 3650b57cec5SDimitry Andric } 3660b57cec5SDimitry Andric 3670b57cec5SDimitry Andric void WasmObjectWriter::startCustomSection(SectionBookkeeping &Section, 3680b57cec5SDimitry Andric StringRef Name) { 3690b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "startCustomSection " << Name << "\n"); 3700b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_CUSTOM); 3710b57cec5SDimitry Andric 3720b57cec5SDimitry Andric // The position where the section header ends, for measuring its size. 3730b57cec5SDimitry Andric Section.PayloadOffset = W.OS.tell(); 3740b57cec5SDimitry Andric 3750b57cec5SDimitry Andric // Custom sections in wasm also have a string identifier. 3760b57cec5SDimitry Andric writeString(Name); 3770b57cec5SDimitry Andric 3780b57cec5SDimitry Andric // The position where the custom section starts. 3790b57cec5SDimitry Andric Section.ContentsOffset = W.OS.tell(); 3800b57cec5SDimitry Andric } 3810b57cec5SDimitry Andric 3820b57cec5SDimitry Andric // Now that the section is complete and we know how big it is, patch up the 3830b57cec5SDimitry Andric // section size field at the start of the section. 3840b57cec5SDimitry Andric void WasmObjectWriter::endSection(SectionBookkeeping &Section) { 3850b57cec5SDimitry Andric uint64_t Size = W.OS.tell(); 3860b57cec5SDimitry Andric // /dev/null doesn't support seek/tell and can report offset of 0. 3870b57cec5SDimitry Andric // Simply skip this patching in that case. 3880b57cec5SDimitry Andric if (!Size) 3890b57cec5SDimitry Andric return; 3900b57cec5SDimitry Andric 3910b57cec5SDimitry Andric Size -= Section.PayloadOffset; 3920b57cec5SDimitry Andric if (uint32_t(Size) != Size) 3930b57cec5SDimitry Andric report_fatal_error("section size does not fit in a uint32_t"); 3940b57cec5SDimitry Andric 3950b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "endSection size=" << Size << "\n"); 3960b57cec5SDimitry Andric 3970b57cec5SDimitry Andric // Write the final section size to the payload_len field, which follows 3980b57cec5SDimitry Andric // the section id byte. 3990b57cec5SDimitry Andric writePatchableLEB(static_cast<raw_pwrite_stream &>(W.OS), Size, 4000b57cec5SDimitry Andric Section.SizeOffset); 4010b57cec5SDimitry Andric } 4020b57cec5SDimitry Andric 4030b57cec5SDimitry Andric // Emit the Wasm header. 4040b57cec5SDimitry Andric void WasmObjectWriter::writeHeader(const MCAssembler &Asm) { 4050b57cec5SDimitry Andric W.OS.write(wasm::WasmMagic, sizeof(wasm::WasmMagic)); 4060b57cec5SDimitry Andric W.write<uint32_t>(wasm::WasmVersion); 4070b57cec5SDimitry Andric } 4080b57cec5SDimitry Andric 4090b57cec5SDimitry Andric void WasmObjectWriter::executePostLayoutBinding(MCAssembler &Asm, 4100b57cec5SDimitry Andric const MCAsmLayout &Layout) { 4110b57cec5SDimitry Andric // Build a map of sections to the function that defines them, for use 4120b57cec5SDimitry Andric // in recordRelocation. 4130b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 4140b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 4150b57cec5SDimitry Andric if (WS.isDefined() && WS.isFunction() && !WS.isVariable()) { 4160b57cec5SDimitry Andric const auto &Sec = static_cast<const MCSectionWasm &>(S.getSection()); 4170b57cec5SDimitry Andric auto Pair = SectionFunctions.insert(std::make_pair(&Sec, &S)); 4180b57cec5SDimitry Andric if (!Pair.second) 4190b57cec5SDimitry Andric report_fatal_error("section already has a defining function: " + 4200b57cec5SDimitry Andric Sec.getSectionName()); 4210b57cec5SDimitry Andric } 4220b57cec5SDimitry Andric } 4230b57cec5SDimitry Andric } 4240b57cec5SDimitry Andric 4250b57cec5SDimitry Andric void WasmObjectWriter::recordRelocation(MCAssembler &Asm, 4260b57cec5SDimitry Andric const MCAsmLayout &Layout, 4270b57cec5SDimitry Andric const MCFragment *Fragment, 4280b57cec5SDimitry Andric const MCFixup &Fixup, MCValue Target, 4290b57cec5SDimitry Andric uint64_t &FixedValue) { 4308bcb0991SDimitry Andric // The WebAssembly backend should never generate FKF_IsPCRel fixups 4318bcb0991SDimitry Andric assert(!(Asm.getBackend().getFixupKindInfo(Fixup.getKind()).Flags & 4328bcb0991SDimitry Andric MCFixupKindInfo::FKF_IsPCRel)); 4338bcb0991SDimitry Andric 4340b57cec5SDimitry Andric const auto &FixupSection = cast<MCSectionWasm>(*Fragment->getParent()); 4350b57cec5SDimitry Andric uint64_t C = Target.getConstant(); 4360b57cec5SDimitry Andric uint64_t FixupOffset = Layout.getFragmentOffset(Fragment) + Fixup.getOffset(); 4370b57cec5SDimitry Andric MCContext &Ctx = Asm.getContext(); 4380b57cec5SDimitry Andric 4390b57cec5SDimitry Andric // The .init_array isn't translated as data, so don't do relocations in it. 4400b57cec5SDimitry Andric if (FixupSection.getSectionName().startswith(".init_array")) 4410b57cec5SDimitry Andric return; 4420b57cec5SDimitry Andric 4430b57cec5SDimitry Andric if (const MCSymbolRefExpr *RefB = Target.getSymB()) { 4448bcb0991SDimitry Andric // To get here the A - B expression must have failed evaluateAsRelocatable. 4458bcb0991SDimitry Andric // This means either A or B must be undefined and in WebAssembly we can't 4468bcb0991SDimitry Andric // support either of those cases. 4478bcb0991SDimitry Andric const auto &SymB = cast<MCSymbolWasm>(RefB->getSymbol()); 4480b57cec5SDimitry Andric Ctx.reportError( 4490b57cec5SDimitry Andric Fixup.getLoc(), 4500b57cec5SDimitry Andric Twine("symbol '") + SymB.getName() + 4518bcb0991SDimitry Andric "': unsupported subtraction expression used in relocation."); 4520b57cec5SDimitry Andric return; 4530b57cec5SDimitry Andric } 4540b57cec5SDimitry Andric 4550b57cec5SDimitry Andric // We either rejected the fixup or folded B into C at this point. 4560b57cec5SDimitry Andric const MCSymbolRefExpr *RefA = Target.getSymA(); 4578bcb0991SDimitry Andric const auto *SymA = cast<MCSymbolWasm>(&RefA->getSymbol()); 4580b57cec5SDimitry Andric 4598bcb0991SDimitry Andric if (SymA->isVariable()) { 4600b57cec5SDimitry Andric const MCExpr *Expr = SymA->getVariableValue(); 4610b57cec5SDimitry Andric const auto *Inner = cast<MCSymbolRefExpr>(Expr); 4620b57cec5SDimitry Andric if (Inner->getKind() == MCSymbolRefExpr::VK_WEAKREF) 4630b57cec5SDimitry Andric llvm_unreachable("weakref used in reloc not yet implemented"); 4640b57cec5SDimitry Andric } 4650b57cec5SDimitry Andric 4660b57cec5SDimitry Andric // Put any constant offset in an addend. Offsets can be negative, and 4670b57cec5SDimitry Andric // LLVM expects wrapping, in contrast to wasm's immediates which can't 4680b57cec5SDimitry Andric // be negative and don't wrap. 4690b57cec5SDimitry Andric FixedValue = 0; 4700b57cec5SDimitry Andric 4710b57cec5SDimitry Andric unsigned Type = TargetObjectWriter->getRelocType(Target, Fixup); 4720b57cec5SDimitry Andric 4730b57cec5SDimitry Andric // Absolute offset within a section or a function. 4740b57cec5SDimitry Andric // Currently only supported for for metadata sections. 4750b57cec5SDimitry Andric // See: test/MC/WebAssembly/blockaddress.ll 4760b57cec5SDimitry Andric if (Type == wasm::R_WASM_FUNCTION_OFFSET_I32 || 4770b57cec5SDimitry Andric Type == wasm::R_WASM_SECTION_OFFSET_I32) { 4780b57cec5SDimitry Andric if (!FixupSection.getKind().isMetadata()) 4790b57cec5SDimitry Andric report_fatal_error("relocations for function or section offsets are " 4800b57cec5SDimitry Andric "only supported in metadata sections"); 4810b57cec5SDimitry Andric 4820b57cec5SDimitry Andric const MCSymbol *SectionSymbol = nullptr; 4830b57cec5SDimitry Andric const MCSection &SecA = SymA->getSection(); 4840b57cec5SDimitry Andric if (SecA.getKind().isText()) 4850b57cec5SDimitry Andric SectionSymbol = SectionFunctions.find(&SecA)->second; 4860b57cec5SDimitry Andric else 4870b57cec5SDimitry Andric SectionSymbol = SecA.getBeginSymbol(); 4880b57cec5SDimitry Andric if (!SectionSymbol) 4890b57cec5SDimitry Andric report_fatal_error("section symbol is required for relocation"); 4900b57cec5SDimitry Andric 4910b57cec5SDimitry Andric C += Layout.getSymbolOffset(*SymA); 4920b57cec5SDimitry Andric SymA = cast<MCSymbolWasm>(SectionSymbol); 4930b57cec5SDimitry Andric } 4940b57cec5SDimitry Andric 4950b57cec5SDimitry Andric // Relocation other than R_WASM_TYPE_INDEX_LEB are required to be 4960b57cec5SDimitry Andric // against a named symbol. 4970b57cec5SDimitry Andric if (Type != wasm::R_WASM_TYPE_INDEX_LEB) { 4980b57cec5SDimitry Andric if (SymA->getName().empty()) 4990b57cec5SDimitry Andric report_fatal_error("relocations against un-named temporaries are not yet " 5000b57cec5SDimitry Andric "supported by wasm"); 5010b57cec5SDimitry Andric 5020b57cec5SDimitry Andric SymA->setUsedInReloc(); 5030b57cec5SDimitry Andric } 5040b57cec5SDimitry Andric 5050b57cec5SDimitry Andric if (RefA->getKind() == MCSymbolRefExpr::VK_GOT) 5060b57cec5SDimitry Andric SymA->setUsedInGOT(); 5070b57cec5SDimitry Andric 5080b57cec5SDimitry Andric WasmRelocationEntry Rec(FixupOffset, SymA, C, Type, &FixupSection); 5090b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "WasmReloc: " << Rec << "\n"); 5100b57cec5SDimitry Andric 5110b57cec5SDimitry Andric if (FixupSection.isWasmData()) { 5120b57cec5SDimitry Andric DataRelocations.push_back(Rec); 5130b57cec5SDimitry Andric } else if (FixupSection.getKind().isText()) { 5140b57cec5SDimitry Andric CodeRelocations.push_back(Rec); 5150b57cec5SDimitry Andric } else if (FixupSection.getKind().isMetadata()) { 5160b57cec5SDimitry Andric CustomSectionsRelocations[&FixupSection].push_back(Rec); 5170b57cec5SDimitry Andric } else { 5180b57cec5SDimitry Andric llvm_unreachable("unexpected section type"); 5190b57cec5SDimitry Andric } 5200b57cec5SDimitry Andric } 5210b57cec5SDimitry Andric 5220b57cec5SDimitry Andric static const MCSymbolWasm *resolveSymbol(const MCSymbolWasm &Symbol) { 5230b57cec5SDimitry Andric const MCSymbolWasm* Ret = &Symbol; 5240b57cec5SDimitry Andric while (Ret->isVariable()) { 5250b57cec5SDimitry Andric const MCExpr *Expr = Ret->getVariableValue(); 5260b57cec5SDimitry Andric auto *Inner = cast<MCSymbolRefExpr>(Expr); 5270b57cec5SDimitry Andric Ret = cast<MCSymbolWasm>(&Inner->getSymbol()); 5280b57cec5SDimitry Andric } 5290b57cec5SDimitry Andric return Ret; 5300b57cec5SDimitry Andric } 5310b57cec5SDimitry Andric 5320b57cec5SDimitry Andric // Compute a value to write into the code at the location covered 5330b57cec5SDimitry Andric // by RelEntry. This value isn't used by the static linker; it just serves 5340b57cec5SDimitry Andric // to make the object format more readable and more likely to be directly 5350b57cec5SDimitry Andric // useable. 5360b57cec5SDimitry Andric uint32_t 5370b57cec5SDimitry Andric WasmObjectWriter::getProvisionalValue(const WasmRelocationEntry &RelEntry) { 5380b57cec5SDimitry Andric if (RelEntry.Type == wasm::R_WASM_GLOBAL_INDEX_LEB && !RelEntry.Symbol->isGlobal()) { 5390b57cec5SDimitry Andric assert(GOTIndices.count(RelEntry.Symbol) > 0 && "symbol not found in GOT index space"); 5400b57cec5SDimitry Andric return GOTIndices[RelEntry.Symbol]; 5410b57cec5SDimitry Andric } 5420b57cec5SDimitry Andric 5430b57cec5SDimitry Andric switch (RelEntry.Type) { 5440b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_REL_SLEB: 5450b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_SLEB: 5460b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_I32: { 5470b57cec5SDimitry Andric // Provisional value is table address of the resolved symbol itself 5480b57cec5SDimitry Andric const MCSymbolWasm *Sym = resolveSymbol(*RelEntry.Symbol); 5490b57cec5SDimitry Andric assert(Sym->isFunction()); 5500b57cec5SDimitry Andric return TableIndices[Sym]; 5510b57cec5SDimitry Andric } 5520b57cec5SDimitry Andric case wasm::R_WASM_TYPE_INDEX_LEB: 5530b57cec5SDimitry Andric // Provisional value is same as the index 5540b57cec5SDimitry Andric return getRelocationIndexValue(RelEntry); 5550b57cec5SDimitry Andric case wasm::R_WASM_FUNCTION_INDEX_LEB: 5560b57cec5SDimitry Andric case wasm::R_WASM_GLOBAL_INDEX_LEB: 5570b57cec5SDimitry Andric case wasm::R_WASM_EVENT_INDEX_LEB: 5580b57cec5SDimitry Andric // Provisional value is function/global/event Wasm index 5590b57cec5SDimitry Andric assert(WasmIndices.count(RelEntry.Symbol) > 0 && "symbol not found in wasm index space"); 5600b57cec5SDimitry Andric return WasmIndices[RelEntry.Symbol]; 5610b57cec5SDimitry Andric case wasm::R_WASM_FUNCTION_OFFSET_I32: 5620b57cec5SDimitry Andric case wasm::R_WASM_SECTION_OFFSET_I32: { 5630b57cec5SDimitry Andric const auto &Section = 5640b57cec5SDimitry Andric static_cast<const MCSectionWasm &>(RelEntry.Symbol->getSection()); 5650b57cec5SDimitry Andric return Section.getSectionOffset() + RelEntry.Addend; 5660b57cec5SDimitry Andric } 5670b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_LEB: 5680b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_I32: 5690b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_REL_SLEB: 5700b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_SLEB: { 5710b57cec5SDimitry Andric // Provisional value is address of the global 5720b57cec5SDimitry Andric const MCSymbolWasm *Sym = resolveSymbol(*RelEntry.Symbol); 5730b57cec5SDimitry Andric // For undefined symbols, use zero 5740b57cec5SDimitry Andric if (!Sym->isDefined()) 5750b57cec5SDimitry Andric return 0; 5760b57cec5SDimitry Andric const wasm::WasmDataReference &Ref = DataLocations[Sym]; 5770b57cec5SDimitry Andric const WasmDataSegment &Segment = DataSegments[Ref.Segment]; 5780b57cec5SDimitry Andric // Ignore overflow. LLVM allows address arithmetic to silently wrap. 5790b57cec5SDimitry Andric return Segment.Offset + Ref.Offset + RelEntry.Addend; 5800b57cec5SDimitry Andric } 5810b57cec5SDimitry Andric default: 5820b57cec5SDimitry Andric llvm_unreachable("invalid relocation type"); 5830b57cec5SDimitry Andric } 5840b57cec5SDimitry Andric } 5850b57cec5SDimitry Andric 5860b57cec5SDimitry Andric static void addData(SmallVectorImpl<char> &DataBytes, 5870b57cec5SDimitry Andric MCSectionWasm &DataSection) { 5880b57cec5SDimitry Andric LLVM_DEBUG(errs() << "addData: " << DataSection.getSectionName() << "\n"); 5890b57cec5SDimitry Andric 5900b57cec5SDimitry Andric DataBytes.resize(alignTo(DataBytes.size(), DataSection.getAlignment())); 5910b57cec5SDimitry Andric 5920b57cec5SDimitry Andric for (const MCFragment &Frag : DataSection) { 5930b57cec5SDimitry Andric if (Frag.hasInstructions()) 5940b57cec5SDimitry Andric report_fatal_error("only data supported in data sections"); 5950b57cec5SDimitry Andric 5960b57cec5SDimitry Andric if (auto *Align = dyn_cast<MCAlignFragment>(&Frag)) { 5970b57cec5SDimitry Andric if (Align->getValueSize() != 1) 5980b57cec5SDimitry Andric report_fatal_error("only byte values supported for alignment"); 5990b57cec5SDimitry Andric // If nops are requested, use zeros, as this is the data section. 6000b57cec5SDimitry Andric uint8_t Value = Align->hasEmitNops() ? 0 : Align->getValue(); 6010b57cec5SDimitry Andric uint64_t Size = 6020b57cec5SDimitry Andric std::min<uint64_t>(alignTo(DataBytes.size(), Align->getAlignment()), 6030b57cec5SDimitry Andric DataBytes.size() + Align->getMaxBytesToEmit()); 6040b57cec5SDimitry Andric DataBytes.resize(Size, Value); 6050b57cec5SDimitry Andric } else if (auto *Fill = dyn_cast<MCFillFragment>(&Frag)) { 6060b57cec5SDimitry Andric int64_t NumValues; 6070b57cec5SDimitry Andric if (!Fill->getNumValues().evaluateAsAbsolute(NumValues)) 6080b57cec5SDimitry Andric llvm_unreachable("The fill should be an assembler constant"); 6090b57cec5SDimitry Andric DataBytes.insert(DataBytes.end(), Fill->getValueSize() * NumValues, 6100b57cec5SDimitry Andric Fill->getValue()); 6110b57cec5SDimitry Andric } else if (auto *LEB = dyn_cast<MCLEBFragment>(&Frag)) { 6120b57cec5SDimitry Andric const SmallVectorImpl<char> &Contents = LEB->getContents(); 6130b57cec5SDimitry Andric DataBytes.insert(DataBytes.end(), Contents.begin(), Contents.end()); 6140b57cec5SDimitry Andric } else { 6150b57cec5SDimitry Andric const auto &DataFrag = cast<MCDataFragment>(Frag); 6160b57cec5SDimitry Andric const SmallVectorImpl<char> &Contents = DataFrag.getContents(); 6170b57cec5SDimitry Andric DataBytes.insert(DataBytes.end(), Contents.begin(), Contents.end()); 6180b57cec5SDimitry Andric } 6190b57cec5SDimitry Andric } 6200b57cec5SDimitry Andric 6210b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "addData -> " << DataBytes.size() << "\n"); 6220b57cec5SDimitry Andric } 6230b57cec5SDimitry Andric 6240b57cec5SDimitry Andric uint32_t 6250b57cec5SDimitry Andric WasmObjectWriter::getRelocationIndexValue(const WasmRelocationEntry &RelEntry) { 6260b57cec5SDimitry Andric if (RelEntry.Type == wasm::R_WASM_TYPE_INDEX_LEB) { 6270b57cec5SDimitry Andric if (!TypeIndices.count(RelEntry.Symbol)) 6280b57cec5SDimitry Andric report_fatal_error("symbol not found in type index space: " + 6290b57cec5SDimitry Andric RelEntry.Symbol->getName()); 6300b57cec5SDimitry Andric return TypeIndices[RelEntry.Symbol]; 6310b57cec5SDimitry Andric } 6320b57cec5SDimitry Andric 6330b57cec5SDimitry Andric return RelEntry.Symbol->getIndex(); 6340b57cec5SDimitry Andric } 6350b57cec5SDimitry Andric 6360b57cec5SDimitry Andric // Apply the portions of the relocation records that we can handle ourselves 6370b57cec5SDimitry Andric // directly. 6380b57cec5SDimitry Andric void WasmObjectWriter::applyRelocations( 6390b57cec5SDimitry Andric ArrayRef<WasmRelocationEntry> Relocations, uint64_t ContentsOffset) { 6400b57cec5SDimitry Andric auto &Stream = static_cast<raw_pwrite_stream &>(W.OS); 6410b57cec5SDimitry Andric for (const WasmRelocationEntry &RelEntry : Relocations) { 6420b57cec5SDimitry Andric uint64_t Offset = ContentsOffset + 6430b57cec5SDimitry Andric RelEntry.FixupSection->getSectionOffset() + 6440b57cec5SDimitry Andric RelEntry.Offset; 6450b57cec5SDimitry Andric 6460b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "applyRelocation: " << RelEntry << "\n"); 6470b57cec5SDimitry Andric uint32_t Value = getProvisionalValue(RelEntry); 6480b57cec5SDimitry Andric 6490b57cec5SDimitry Andric switch (RelEntry.Type) { 6500b57cec5SDimitry Andric case wasm::R_WASM_FUNCTION_INDEX_LEB: 6510b57cec5SDimitry Andric case wasm::R_WASM_TYPE_INDEX_LEB: 6520b57cec5SDimitry Andric case wasm::R_WASM_GLOBAL_INDEX_LEB: 6530b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_LEB: 6540b57cec5SDimitry Andric case wasm::R_WASM_EVENT_INDEX_LEB: 6550b57cec5SDimitry Andric writePatchableLEB(Stream, Value, Offset); 6560b57cec5SDimitry Andric break; 6570b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_I32: 6580b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_I32: 6590b57cec5SDimitry Andric case wasm::R_WASM_FUNCTION_OFFSET_I32: 6600b57cec5SDimitry Andric case wasm::R_WASM_SECTION_OFFSET_I32: 6610b57cec5SDimitry Andric writeI32(Stream, Value, Offset); 6620b57cec5SDimitry Andric break; 6630b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_SLEB: 6640b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_REL_SLEB: 6650b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_SLEB: 6660b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_REL_SLEB: 6670b57cec5SDimitry Andric writePatchableSLEB(Stream, Value, Offset); 6680b57cec5SDimitry Andric break; 6690b57cec5SDimitry Andric default: 6700b57cec5SDimitry Andric llvm_unreachable("invalid relocation type"); 6710b57cec5SDimitry Andric } 6720b57cec5SDimitry Andric } 6730b57cec5SDimitry Andric } 6740b57cec5SDimitry Andric 6750b57cec5SDimitry Andric void WasmObjectWriter::writeTypeSection(ArrayRef<WasmSignature> Signatures) { 6760b57cec5SDimitry Andric if (Signatures.empty()) 6770b57cec5SDimitry Andric return; 6780b57cec5SDimitry Andric 6790b57cec5SDimitry Andric SectionBookkeeping Section; 6800b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_TYPE); 6810b57cec5SDimitry Andric 6820b57cec5SDimitry Andric encodeULEB128(Signatures.size(), W.OS); 6830b57cec5SDimitry Andric 6840b57cec5SDimitry Andric for (const WasmSignature &Sig : Signatures) { 6850b57cec5SDimitry Andric W.OS << char(wasm::WASM_TYPE_FUNC); 6860b57cec5SDimitry Andric encodeULEB128(Sig.Params.size(), W.OS); 6870b57cec5SDimitry Andric for (wasm::ValType Ty : Sig.Params) 6880b57cec5SDimitry Andric writeValueType(Ty); 6890b57cec5SDimitry Andric encodeULEB128(Sig.Returns.size(), W.OS); 6900b57cec5SDimitry Andric for (wasm::ValType Ty : Sig.Returns) 6910b57cec5SDimitry Andric writeValueType(Ty); 6920b57cec5SDimitry Andric } 6930b57cec5SDimitry Andric 6940b57cec5SDimitry Andric endSection(Section); 6950b57cec5SDimitry Andric } 6960b57cec5SDimitry Andric 6970b57cec5SDimitry Andric void WasmObjectWriter::writeImportSection(ArrayRef<wasm::WasmImport> Imports, 6980b57cec5SDimitry Andric uint32_t DataSize, 6990b57cec5SDimitry Andric uint32_t NumElements) { 7000b57cec5SDimitry Andric if (Imports.empty()) 7010b57cec5SDimitry Andric return; 7020b57cec5SDimitry Andric 7030b57cec5SDimitry Andric uint32_t NumPages = (DataSize + wasm::WasmPageSize - 1) / wasm::WasmPageSize; 7040b57cec5SDimitry Andric 7050b57cec5SDimitry Andric SectionBookkeeping Section; 7060b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_IMPORT); 7070b57cec5SDimitry Andric 7080b57cec5SDimitry Andric encodeULEB128(Imports.size(), W.OS); 7090b57cec5SDimitry Andric for (const wasm::WasmImport &Import : Imports) { 7100b57cec5SDimitry Andric writeString(Import.Module); 7110b57cec5SDimitry Andric writeString(Import.Field); 7120b57cec5SDimitry Andric W.OS << char(Import.Kind); 7130b57cec5SDimitry Andric 7140b57cec5SDimitry Andric switch (Import.Kind) { 7150b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_FUNCTION: 7160b57cec5SDimitry Andric encodeULEB128(Import.SigIndex, W.OS); 7170b57cec5SDimitry Andric break; 7180b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_GLOBAL: 7190b57cec5SDimitry Andric W.OS << char(Import.Global.Type); 7200b57cec5SDimitry Andric W.OS << char(Import.Global.Mutable ? 1 : 0); 7210b57cec5SDimitry Andric break; 7220b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_MEMORY: 7230b57cec5SDimitry Andric encodeULEB128(0, W.OS); // flags 7240b57cec5SDimitry Andric encodeULEB128(NumPages, W.OS); // initial 7250b57cec5SDimitry Andric break; 7260b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_TABLE: 7270b57cec5SDimitry Andric W.OS << char(Import.Table.ElemType); 7280b57cec5SDimitry Andric encodeULEB128(0, W.OS); // flags 7290b57cec5SDimitry Andric encodeULEB128(NumElements, W.OS); // initial 7300b57cec5SDimitry Andric break; 7310b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_EVENT: 7320b57cec5SDimitry Andric encodeULEB128(Import.Event.Attribute, W.OS); 7330b57cec5SDimitry Andric encodeULEB128(Import.Event.SigIndex, W.OS); 7340b57cec5SDimitry Andric break; 7350b57cec5SDimitry Andric default: 7360b57cec5SDimitry Andric llvm_unreachable("unsupported import kind"); 7370b57cec5SDimitry Andric } 7380b57cec5SDimitry Andric } 7390b57cec5SDimitry Andric 7400b57cec5SDimitry Andric endSection(Section); 7410b57cec5SDimitry Andric } 7420b57cec5SDimitry Andric 7430b57cec5SDimitry Andric void WasmObjectWriter::writeFunctionSection(ArrayRef<WasmFunction> Functions) { 7440b57cec5SDimitry Andric if (Functions.empty()) 7450b57cec5SDimitry Andric return; 7460b57cec5SDimitry Andric 7470b57cec5SDimitry Andric SectionBookkeeping Section; 7480b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_FUNCTION); 7490b57cec5SDimitry Andric 7500b57cec5SDimitry Andric encodeULEB128(Functions.size(), W.OS); 7510b57cec5SDimitry Andric for (const WasmFunction &Func : Functions) 7520b57cec5SDimitry Andric encodeULEB128(Func.SigIndex, W.OS); 7530b57cec5SDimitry Andric 7540b57cec5SDimitry Andric endSection(Section); 7550b57cec5SDimitry Andric } 7560b57cec5SDimitry Andric 7570b57cec5SDimitry Andric void WasmObjectWriter::writeEventSection(ArrayRef<wasm::WasmEventType> Events) { 7580b57cec5SDimitry Andric if (Events.empty()) 7590b57cec5SDimitry Andric return; 7600b57cec5SDimitry Andric 7610b57cec5SDimitry Andric SectionBookkeeping Section; 7620b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_EVENT); 7630b57cec5SDimitry Andric 7640b57cec5SDimitry Andric encodeULEB128(Events.size(), W.OS); 7650b57cec5SDimitry Andric for (const wasm::WasmEventType &Event : Events) { 7660b57cec5SDimitry Andric encodeULEB128(Event.Attribute, W.OS); 7670b57cec5SDimitry Andric encodeULEB128(Event.SigIndex, W.OS); 7680b57cec5SDimitry Andric } 7690b57cec5SDimitry Andric 7700b57cec5SDimitry Andric endSection(Section); 7710b57cec5SDimitry Andric } 7720b57cec5SDimitry Andric 7730b57cec5SDimitry Andric void WasmObjectWriter::writeExportSection(ArrayRef<wasm::WasmExport> Exports) { 7740b57cec5SDimitry Andric if (Exports.empty()) 7750b57cec5SDimitry Andric return; 7760b57cec5SDimitry Andric 7770b57cec5SDimitry Andric SectionBookkeeping Section; 7780b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_EXPORT); 7790b57cec5SDimitry Andric 7800b57cec5SDimitry Andric encodeULEB128(Exports.size(), W.OS); 7810b57cec5SDimitry Andric for (const wasm::WasmExport &Export : Exports) { 7820b57cec5SDimitry Andric writeString(Export.Name); 7830b57cec5SDimitry Andric W.OS << char(Export.Kind); 7840b57cec5SDimitry Andric encodeULEB128(Export.Index, W.OS); 7850b57cec5SDimitry Andric } 7860b57cec5SDimitry Andric 7870b57cec5SDimitry Andric endSection(Section); 7880b57cec5SDimitry Andric } 7890b57cec5SDimitry Andric 7900b57cec5SDimitry Andric void WasmObjectWriter::writeElemSection(ArrayRef<uint32_t> TableElems) { 7910b57cec5SDimitry Andric if (TableElems.empty()) 7920b57cec5SDimitry Andric return; 7930b57cec5SDimitry Andric 7940b57cec5SDimitry Andric SectionBookkeeping Section; 7950b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_ELEM); 7960b57cec5SDimitry Andric 7970b57cec5SDimitry Andric encodeULEB128(1, W.OS); // number of "segments" 7980b57cec5SDimitry Andric encodeULEB128(0, W.OS); // the table index 7990b57cec5SDimitry Andric 8000b57cec5SDimitry Andric // init expr for starting offset 8010b57cec5SDimitry Andric W.OS << char(wasm::WASM_OPCODE_I32_CONST); 8020b57cec5SDimitry Andric encodeSLEB128(InitialTableOffset, W.OS); 8030b57cec5SDimitry Andric W.OS << char(wasm::WASM_OPCODE_END); 8040b57cec5SDimitry Andric 8050b57cec5SDimitry Andric encodeULEB128(TableElems.size(), W.OS); 8060b57cec5SDimitry Andric for (uint32_t Elem : TableElems) 8070b57cec5SDimitry Andric encodeULEB128(Elem, W.OS); 8080b57cec5SDimitry Andric 8090b57cec5SDimitry Andric endSection(Section); 8100b57cec5SDimitry Andric } 8110b57cec5SDimitry Andric 8120b57cec5SDimitry Andric void WasmObjectWriter::writeDataCountSection() { 8130b57cec5SDimitry Andric if (DataSegments.empty()) 8140b57cec5SDimitry Andric return; 8150b57cec5SDimitry Andric 8160b57cec5SDimitry Andric SectionBookkeeping Section; 8170b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_DATACOUNT); 8180b57cec5SDimitry Andric encodeULEB128(DataSegments.size(), W.OS); 8190b57cec5SDimitry Andric endSection(Section); 8200b57cec5SDimitry Andric } 8210b57cec5SDimitry Andric 8220b57cec5SDimitry Andric void WasmObjectWriter::writeCodeSection(const MCAssembler &Asm, 8230b57cec5SDimitry Andric const MCAsmLayout &Layout, 8240b57cec5SDimitry Andric ArrayRef<WasmFunction> Functions) { 8250b57cec5SDimitry Andric if (Functions.empty()) 8260b57cec5SDimitry Andric return; 8270b57cec5SDimitry Andric 8280b57cec5SDimitry Andric SectionBookkeeping Section; 8290b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_CODE); 8300b57cec5SDimitry Andric CodeSectionIndex = Section.Index; 8310b57cec5SDimitry Andric 8320b57cec5SDimitry Andric encodeULEB128(Functions.size(), W.OS); 8330b57cec5SDimitry Andric 8340b57cec5SDimitry Andric for (const WasmFunction &Func : Functions) { 8350b57cec5SDimitry Andric auto &FuncSection = static_cast<MCSectionWasm &>(Func.Sym->getSection()); 8360b57cec5SDimitry Andric 8370b57cec5SDimitry Andric int64_t Size = 0; 8380b57cec5SDimitry Andric if (!Func.Sym->getSize()->evaluateAsAbsolute(Size, Layout)) 8390b57cec5SDimitry Andric report_fatal_error(".size expression must be evaluatable"); 8400b57cec5SDimitry Andric 8410b57cec5SDimitry Andric encodeULEB128(Size, W.OS); 8420b57cec5SDimitry Andric FuncSection.setSectionOffset(W.OS.tell() - Section.ContentsOffset); 8430b57cec5SDimitry Andric Asm.writeSectionData(W.OS, &FuncSection, Layout); 8440b57cec5SDimitry Andric } 8450b57cec5SDimitry Andric 8460b57cec5SDimitry Andric // Apply fixups. 8470b57cec5SDimitry Andric applyRelocations(CodeRelocations, Section.ContentsOffset); 8480b57cec5SDimitry Andric 8490b57cec5SDimitry Andric endSection(Section); 8500b57cec5SDimitry Andric } 8510b57cec5SDimitry Andric 8520b57cec5SDimitry Andric void WasmObjectWriter::writeDataSection() { 8530b57cec5SDimitry Andric if (DataSegments.empty()) 8540b57cec5SDimitry Andric return; 8550b57cec5SDimitry Andric 8560b57cec5SDimitry Andric SectionBookkeeping Section; 8570b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_DATA); 8580b57cec5SDimitry Andric DataSectionIndex = Section.Index; 8590b57cec5SDimitry Andric 8600b57cec5SDimitry Andric encodeULEB128(DataSegments.size(), W.OS); // count 8610b57cec5SDimitry Andric 8620b57cec5SDimitry Andric for (const WasmDataSegment &Segment : DataSegments) { 8630b57cec5SDimitry Andric encodeULEB128(Segment.InitFlags, W.OS); // flags 8640b57cec5SDimitry Andric if (Segment.InitFlags & wasm::WASM_SEGMENT_HAS_MEMINDEX) 8650b57cec5SDimitry Andric encodeULEB128(0, W.OS); // memory index 8660b57cec5SDimitry Andric if ((Segment.InitFlags & wasm::WASM_SEGMENT_IS_PASSIVE) == 0) { 8670b57cec5SDimitry Andric W.OS << char(wasm::WASM_OPCODE_I32_CONST); 8680b57cec5SDimitry Andric encodeSLEB128(Segment.Offset, W.OS); // offset 8690b57cec5SDimitry Andric W.OS << char(wasm::WASM_OPCODE_END); 8700b57cec5SDimitry Andric } 8710b57cec5SDimitry Andric encodeULEB128(Segment.Data.size(), W.OS); // size 8720b57cec5SDimitry Andric Segment.Section->setSectionOffset(W.OS.tell() - Section.ContentsOffset); 8730b57cec5SDimitry Andric W.OS << Segment.Data; // data 8740b57cec5SDimitry Andric } 8750b57cec5SDimitry Andric 8760b57cec5SDimitry Andric // Apply fixups. 8770b57cec5SDimitry Andric applyRelocations(DataRelocations, Section.ContentsOffset); 8780b57cec5SDimitry Andric 8790b57cec5SDimitry Andric endSection(Section); 8800b57cec5SDimitry Andric } 8810b57cec5SDimitry Andric 8820b57cec5SDimitry Andric void WasmObjectWriter::writeRelocSection( 8830b57cec5SDimitry Andric uint32_t SectionIndex, StringRef Name, 8840b57cec5SDimitry Andric std::vector<WasmRelocationEntry> &Relocs) { 8850b57cec5SDimitry Andric // See: https://github.com/WebAssembly/tool-conventions/blob/master/Linking.md 8860b57cec5SDimitry Andric // for descriptions of the reloc sections. 8870b57cec5SDimitry Andric 8880b57cec5SDimitry Andric if (Relocs.empty()) 8890b57cec5SDimitry Andric return; 8900b57cec5SDimitry Andric 8910b57cec5SDimitry Andric // First, ensure the relocations are sorted in offset order. In general they 8920b57cec5SDimitry Andric // should already be sorted since `recordRelocation` is called in offset 8930b57cec5SDimitry Andric // order, but for the code section we combine many MC sections into single 8940b57cec5SDimitry Andric // wasm section, and this order is determined by the order of Asm.Symbols() 8950b57cec5SDimitry Andric // not the sections order. 8960b57cec5SDimitry Andric llvm::stable_sort( 8970b57cec5SDimitry Andric Relocs, [](const WasmRelocationEntry &A, const WasmRelocationEntry &B) { 8980b57cec5SDimitry Andric return (A.Offset + A.FixupSection->getSectionOffset()) < 8990b57cec5SDimitry Andric (B.Offset + B.FixupSection->getSectionOffset()); 9000b57cec5SDimitry Andric }); 9010b57cec5SDimitry Andric 9020b57cec5SDimitry Andric SectionBookkeeping Section; 9030b57cec5SDimitry Andric startCustomSection(Section, std::string("reloc.") + Name.str()); 9040b57cec5SDimitry Andric 9050b57cec5SDimitry Andric encodeULEB128(SectionIndex, W.OS); 9060b57cec5SDimitry Andric encodeULEB128(Relocs.size(), W.OS); 9070b57cec5SDimitry Andric for (const WasmRelocationEntry &RelEntry : Relocs) { 9080b57cec5SDimitry Andric uint64_t Offset = 9090b57cec5SDimitry Andric RelEntry.Offset + RelEntry.FixupSection->getSectionOffset(); 9100b57cec5SDimitry Andric uint32_t Index = getRelocationIndexValue(RelEntry); 9110b57cec5SDimitry Andric 9120b57cec5SDimitry Andric W.OS << char(RelEntry.Type); 9130b57cec5SDimitry Andric encodeULEB128(Offset, W.OS); 9140b57cec5SDimitry Andric encodeULEB128(Index, W.OS); 9150b57cec5SDimitry Andric if (RelEntry.hasAddend()) 9160b57cec5SDimitry Andric encodeSLEB128(RelEntry.Addend, W.OS); 9170b57cec5SDimitry Andric } 9180b57cec5SDimitry Andric 9190b57cec5SDimitry Andric endSection(Section); 9200b57cec5SDimitry Andric } 9210b57cec5SDimitry Andric 9220b57cec5SDimitry Andric void WasmObjectWriter::writeCustomRelocSections() { 9230b57cec5SDimitry Andric for (const auto &Sec : CustomSections) { 9240b57cec5SDimitry Andric auto &Relocations = CustomSectionsRelocations[Sec.Section]; 9250b57cec5SDimitry Andric writeRelocSection(Sec.OutputIndex, Sec.Name, Relocations); 9260b57cec5SDimitry Andric } 9270b57cec5SDimitry Andric } 9280b57cec5SDimitry Andric 9290b57cec5SDimitry Andric void WasmObjectWriter::writeLinkingMetaDataSection( 9300b57cec5SDimitry Andric ArrayRef<wasm::WasmSymbolInfo> SymbolInfos, 9310b57cec5SDimitry Andric ArrayRef<std::pair<uint16_t, uint32_t>> InitFuncs, 9320b57cec5SDimitry Andric const std::map<StringRef, std::vector<WasmComdatEntry>> &Comdats) { 9330b57cec5SDimitry Andric SectionBookkeeping Section; 9340b57cec5SDimitry Andric startCustomSection(Section, "linking"); 9350b57cec5SDimitry Andric encodeULEB128(wasm::WasmMetadataVersion, W.OS); 9360b57cec5SDimitry Andric 9370b57cec5SDimitry Andric SectionBookkeeping SubSection; 9380b57cec5SDimitry Andric if (SymbolInfos.size() != 0) { 9390b57cec5SDimitry Andric startSection(SubSection, wasm::WASM_SYMBOL_TABLE); 9400b57cec5SDimitry Andric encodeULEB128(SymbolInfos.size(), W.OS); 9410b57cec5SDimitry Andric for (const wasm::WasmSymbolInfo &Sym : SymbolInfos) { 9420b57cec5SDimitry Andric encodeULEB128(Sym.Kind, W.OS); 9430b57cec5SDimitry Andric encodeULEB128(Sym.Flags, W.OS); 9440b57cec5SDimitry Andric switch (Sym.Kind) { 9450b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_FUNCTION: 9460b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_GLOBAL: 9470b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_EVENT: 9480b57cec5SDimitry Andric encodeULEB128(Sym.ElementIndex, W.OS); 9490b57cec5SDimitry Andric if ((Sym.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0 || 9500b57cec5SDimitry Andric (Sym.Flags & wasm::WASM_SYMBOL_EXPLICIT_NAME) != 0) 9510b57cec5SDimitry Andric writeString(Sym.Name); 9520b57cec5SDimitry Andric break; 9530b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_DATA: 9540b57cec5SDimitry Andric writeString(Sym.Name); 9550b57cec5SDimitry Andric if ((Sym.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0) { 9560b57cec5SDimitry Andric encodeULEB128(Sym.DataRef.Segment, W.OS); 9570b57cec5SDimitry Andric encodeULEB128(Sym.DataRef.Offset, W.OS); 9580b57cec5SDimitry Andric encodeULEB128(Sym.DataRef.Size, W.OS); 9590b57cec5SDimitry Andric } 9600b57cec5SDimitry Andric break; 9610b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_SECTION: { 9620b57cec5SDimitry Andric const uint32_t SectionIndex = 9630b57cec5SDimitry Andric CustomSections[Sym.ElementIndex].OutputIndex; 9640b57cec5SDimitry Andric encodeULEB128(SectionIndex, W.OS); 9650b57cec5SDimitry Andric break; 9660b57cec5SDimitry Andric } 9670b57cec5SDimitry Andric default: 9680b57cec5SDimitry Andric llvm_unreachable("unexpected kind"); 9690b57cec5SDimitry Andric } 9700b57cec5SDimitry Andric } 9710b57cec5SDimitry Andric endSection(SubSection); 9720b57cec5SDimitry Andric } 9730b57cec5SDimitry Andric 9740b57cec5SDimitry Andric if (DataSegments.size()) { 9750b57cec5SDimitry Andric startSection(SubSection, wasm::WASM_SEGMENT_INFO); 9760b57cec5SDimitry Andric encodeULEB128(DataSegments.size(), W.OS); 9770b57cec5SDimitry Andric for (const WasmDataSegment &Segment : DataSegments) { 9780b57cec5SDimitry Andric writeString(Segment.Name); 9790b57cec5SDimitry Andric encodeULEB128(Segment.Alignment, W.OS); 9800b57cec5SDimitry Andric encodeULEB128(Segment.LinkerFlags, W.OS); 9810b57cec5SDimitry Andric } 9820b57cec5SDimitry Andric endSection(SubSection); 9830b57cec5SDimitry Andric } 9840b57cec5SDimitry Andric 9850b57cec5SDimitry Andric if (!InitFuncs.empty()) { 9860b57cec5SDimitry Andric startSection(SubSection, wasm::WASM_INIT_FUNCS); 9870b57cec5SDimitry Andric encodeULEB128(InitFuncs.size(), W.OS); 9880b57cec5SDimitry Andric for (auto &StartFunc : InitFuncs) { 9890b57cec5SDimitry Andric encodeULEB128(StartFunc.first, W.OS); // priority 9900b57cec5SDimitry Andric encodeULEB128(StartFunc.second, W.OS); // function index 9910b57cec5SDimitry Andric } 9920b57cec5SDimitry Andric endSection(SubSection); 9930b57cec5SDimitry Andric } 9940b57cec5SDimitry Andric 9950b57cec5SDimitry Andric if (Comdats.size()) { 9960b57cec5SDimitry Andric startSection(SubSection, wasm::WASM_COMDAT_INFO); 9970b57cec5SDimitry Andric encodeULEB128(Comdats.size(), W.OS); 9980b57cec5SDimitry Andric for (const auto &C : Comdats) { 9990b57cec5SDimitry Andric writeString(C.first); 10000b57cec5SDimitry Andric encodeULEB128(0, W.OS); // flags for future use 10010b57cec5SDimitry Andric encodeULEB128(C.second.size(), W.OS); 10020b57cec5SDimitry Andric for (const WasmComdatEntry &Entry : C.second) { 10030b57cec5SDimitry Andric encodeULEB128(Entry.Kind, W.OS); 10040b57cec5SDimitry Andric encodeULEB128(Entry.Index, W.OS); 10050b57cec5SDimitry Andric } 10060b57cec5SDimitry Andric } 10070b57cec5SDimitry Andric endSection(SubSection); 10080b57cec5SDimitry Andric } 10090b57cec5SDimitry Andric 10100b57cec5SDimitry Andric endSection(Section); 10110b57cec5SDimitry Andric } 10120b57cec5SDimitry Andric 10130b57cec5SDimitry Andric void WasmObjectWriter::writeCustomSection(WasmCustomSection &CustomSection, 10140b57cec5SDimitry Andric const MCAssembler &Asm, 10150b57cec5SDimitry Andric const MCAsmLayout &Layout) { 10160b57cec5SDimitry Andric SectionBookkeeping Section; 10170b57cec5SDimitry Andric auto *Sec = CustomSection.Section; 10180b57cec5SDimitry Andric startCustomSection(Section, CustomSection.Name); 10190b57cec5SDimitry Andric 10200b57cec5SDimitry Andric Sec->setSectionOffset(W.OS.tell() - Section.ContentsOffset); 10210b57cec5SDimitry Andric Asm.writeSectionData(W.OS, Sec, Layout); 10220b57cec5SDimitry Andric 10230b57cec5SDimitry Andric CustomSection.OutputContentsOffset = Section.ContentsOffset; 10240b57cec5SDimitry Andric CustomSection.OutputIndex = Section.Index; 10250b57cec5SDimitry Andric 10260b57cec5SDimitry Andric endSection(Section); 10270b57cec5SDimitry Andric 10280b57cec5SDimitry Andric // Apply fixups. 10290b57cec5SDimitry Andric auto &Relocations = CustomSectionsRelocations[CustomSection.Section]; 10300b57cec5SDimitry Andric applyRelocations(Relocations, CustomSection.OutputContentsOffset); 10310b57cec5SDimitry Andric } 10320b57cec5SDimitry Andric 10330b57cec5SDimitry Andric uint32_t WasmObjectWriter::getFunctionType(const MCSymbolWasm &Symbol) { 10340b57cec5SDimitry Andric assert(Symbol.isFunction()); 10350b57cec5SDimitry Andric assert(TypeIndices.count(&Symbol)); 10360b57cec5SDimitry Andric return TypeIndices[&Symbol]; 10370b57cec5SDimitry Andric } 10380b57cec5SDimitry Andric 10390b57cec5SDimitry Andric uint32_t WasmObjectWriter::getEventType(const MCSymbolWasm &Symbol) { 10400b57cec5SDimitry Andric assert(Symbol.isEvent()); 10410b57cec5SDimitry Andric assert(TypeIndices.count(&Symbol)); 10420b57cec5SDimitry Andric return TypeIndices[&Symbol]; 10430b57cec5SDimitry Andric } 10440b57cec5SDimitry Andric 10450b57cec5SDimitry Andric void WasmObjectWriter::registerFunctionType(const MCSymbolWasm &Symbol) { 10460b57cec5SDimitry Andric assert(Symbol.isFunction()); 10470b57cec5SDimitry Andric 10480b57cec5SDimitry Andric WasmSignature S; 10490b57cec5SDimitry Andric const MCSymbolWasm *ResolvedSym = resolveSymbol(Symbol); 10500b57cec5SDimitry Andric if (auto *Sig = ResolvedSym->getSignature()) { 10510b57cec5SDimitry Andric S.Returns = Sig->Returns; 10520b57cec5SDimitry Andric S.Params = Sig->Params; 10530b57cec5SDimitry Andric } 10540b57cec5SDimitry Andric 10550b57cec5SDimitry Andric auto Pair = SignatureIndices.insert(std::make_pair(S, Signatures.size())); 10560b57cec5SDimitry Andric if (Pair.second) 10570b57cec5SDimitry Andric Signatures.push_back(S); 10580b57cec5SDimitry Andric TypeIndices[&Symbol] = Pair.first->second; 10590b57cec5SDimitry Andric 10600b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "registerFunctionType: " << Symbol 10610b57cec5SDimitry Andric << " new:" << Pair.second << "\n"); 10620b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> type index: " << Pair.first->second << "\n"); 10630b57cec5SDimitry Andric } 10640b57cec5SDimitry Andric 10650b57cec5SDimitry Andric void WasmObjectWriter::registerEventType(const MCSymbolWasm &Symbol) { 10660b57cec5SDimitry Andric assert(Symbol.isEvent()); 10670b57cec5SDimitry Andric 10680b57cec5SDimitry Andric // TODO Currently we don't generate imported exceptions, but if we do, we 10690b57cec5SDimitry Andric // should have a way of infering types of imported exceptions. 10700b57cec5SDimitry Andric WasmSignature S; 10710b57cec5SDimitry Andric if (auto *Sig = Symbol.getSignature()) { 10720b57cec5SDimitry Andric S.Returns = Sig->Returns; 10730b57cec5SDimitry Andric S.Params = Sig->Params; 10740b57cec5SDimitry Andric } 10750b57cec5SDimitry Andric 10760b57cec5SDimitry Andric auto Pair = SignatureIndices.insert(std::make_pair(S, Signatures.size())); 10770b57cec5SDimitry Andric if (Pair.second) 10780b57cec5SDimitry Andric Signatures.push_back(S); 10790b57cec5SDimitry Andric TypeIndices[&Symbol] = Pair.first->second; 10800b57cec5SDimitry Andric 10810b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "registerEventType: " << Symbol << " new:" << Pair.second 10820b57cec5SDimitry Andric << "\n"); 10830b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> type index: " << Pair.first->second << "\n"); 10840b57cec5SDimitry Andric } 10850b57cec5SDimitry Andric 10860b57cec5SDimitry Andric static bool isInSymtab(const MCSymbolWasm &Sym) { 10870b57cec5SDimitry Andric if (Sym.isUsedInReloc()) 10880b57cec5SDimitry Andric return true; 10890b57cec5SDimitry Andric 10900b57cec5SDimitry Andric if (Sym.isComdat() && !Sym.isDefined()) 10910b57cec5SDimitry Andric return false; 10920b57cec5SDimitry Andric 10930b57cec5SDimitry Andric if (Sym.isTemporary() && Sym.getName().empty()) 10940b57cec5SDimitry Andric return false; 10950b57cec5SDimitry Andric 10960b57cec5SDimitry Andric if (Sym.isTemporary() && Sym.isData() && !Sym.getSize()) 10970b57cec5SDimitry Andric return false; 10980b57cec5SDimitry Andric 10990b57cec5SDimitry Andric if (Sym.isSection()) 11000b57cec5SDimitry Andric return false; 11010b57cec5SDimitry Andric 11020b57cec5SDimitry Andric return true; 11030b57cec5SDimitry Andric } 11040b57cec5SDimitry Andric 11050b57cec5SDimitry Andric uint64_t WasmObjectWriter::writeObject(MCAssembler &Asm, 11060b57cec5SDimitry Andric const MCAsmLayout &Layout) { 11070b57cec5SDimitry Andric uint64_t StartOffset = W.OS.tell(); 11080b57cec5SDimitry Andric 11090b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "WasmObjectWriter::writeObject\n"); 11100b57cec5SDimitry Andric 11110b57cec5SDimitry Andric // Collect information from the available symbols. 11120b57cec5SDimitry Andric SmallVector<WasmFunction, 4> Functions; 11130b57cec5SDimitry Andric SmallVector<uint32_t, 4> TableElems; 11140b57cec5SDimitry Andric SmallVector<wasm::WasmImport, 4> Imports; 11150b57cec5SDimitry Andric SmallVector<wasm::WasmExport, 4> Exports; 11160b57cec5SDimitry Andric SmallVector<wasm::WasmEventType, 1> Events; 11170b57cec5SDimitry Andric SmallVector<wasm::WasmSymbolInfo, 4> SymbolInfos; 11180b57cec5SDimitry Andric SmallVector<std::pair<uint16_t, uint32_t>, 2> InitFuncs; 11190b57cec5SDimitry Andric std::map<StringRef, std::vector<WasmComdatEntry>> Comdats; 11200b57cec5SDimitry Andric uint32_t DataSize = 0; 11210b57cec5SDimitry Andric 11220b57cec5SDimitry Andric // For now, always emit the memory import, since loads and stores are not 11230b57cec5SDimitry Andric // valid without it. In the future, we could perhaps be more clever and omit 11240b57cec5SDimitry Andric // it if there are no loads or stores. 11250b57cec5SDimitry Andric wasm::WasmImport MemImport; 11260b57cec5SDimitry Andric MemImport.Module = "env"; 11270b57cec5SDimitry Andric MemImport.Field = "__linear_memory"; 11280b57cec5SDimitry Andric MemImport.Kind = wasm::WASM_EXTERNAL_MEMORY; 11290b57cec5SDimitry Andric Imports.push_back(MemImport); 11300b57cec5SDimitry Andric 11310b57cec5SDimitry Andric // For now, always emit the table section, since indirect calls are not 11320b57cec5SDimitry Andric // valid without it. In the future, we could perhaps be more clever and omit 11330b57cec5SDimitry Andric // it if there are no indirect calls. 11340b57cec5SDimitry Andric wasm::WasmImport TableImport; 11350b57cec5SDimitry Andric TableImport.Module = "env"; 11360b57cec5SDimitry Andric TableImport.Field = "__indirect_function_table"; 11370b57cec5SDimitry Andric TableImport.Kind = wasm::WASM_EXTERNAL_TABLE; 11380b57cec5SDimitry Andric TableImport.Table.ElemType = wasm::WASM_TYPE_FUNCREF; 11390b57cec5SDimitry Andric Imports.push_back(TableImport); 11400b57cec5SDimitry Andric 11410b57cec5SDimitry Andric // Populate SignatureIndices, and Imports and WasmIndices for undefined 11420b57cec5SDimitry Andric // symbols. This must be done before populating WasmIndices for defined 11430b57cec5SDimitry Andric // symbols. 11440b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 11450b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 11460b57cec5SDimitry Andric 11470b57cec5SDimitry Andric // Register types for all functions, including those with private linkage 11480b57cec5SDimitry Andric // (because wasm always needs a type signature). 11490b57cec5SDimitry Andric if (WS.isFunction()) 11500b57cec5SDimitry Andric registerFunctionType(WS); 11510b57cec5SDimitry Andric 11520b57cec5SDimitry Andric if (WS.isEvent()) 11530b57cec5SDimitry Andric registerEventType(WS); 11540b57cec5SDimitry Andric 11550b57cec5SDimitry Andric if (WS.isTemporary()) 11560b57cec5SDimitry Andric continue; 11570b57cec5SDimitry Andric 11580b57cec5SDimitry Andric // If the symbol is not defined in this translation unit, import it. 11590b57cec5SDimitry Andric if (!WS.isDefined() && !WS.isComdat()) { 11600b57cec5SDimitry Andric if (WS.isFunction()) { 11610b57cec5SDimitry Andric wasm::WasmImport Import; 11620b57cec5SDimitry Andric Import.Module = WS.getImportModule(); 11630b57cec5SDimitry Andric Import.Field = WS.getImportName(); 11640b57cec5SDimitry Andric Import.Kind = wasm::WASM_EXTERNAL_FUNCTION; 11650b57cec5SDimitry Andric Import.SigIndex = getFunctionType(WS); 11660b57cec5SDimitry Andric Imports.push_back(Import); 11670b57cec5SDimitry Andric assert(WasmIndices.count(&WS) == 0); 11680b57cec5SDimitry Andric WasmIndices[&WS] = NumFunctionImports++; 11690b57cec5SDimitry Andric } else if (WS.isGlobal()) { 11700b57cec5SDimitry Andric if (WS.isWeak()) 11710b57cec5SDimitry Andric report_fatal_error("undefined global symbol cannot be weak"); 11720b57cec5SDimitry Andric 11730b57cec5SDimitry Andric wasm::WasmImport Import; 11740b57cec5SDimitry Andric Import.Field = WS.getImportName(); 11750b57cec5SDimitry Andric Import.Kind = wasm::WASM_EXTERNAL_GLOBAL; 11760b57cec5SDimitry Andric Import.Module = WS.getImportModule(); 11770b57cec5SDimitry Andric Import.Global = WS.getGlobalType(); 11780b57cec5SDimitry Andric Imports.push_back(Import); 11790b57cec5SDimitry Andric assert(WasmIndices.count(&WS) == 0); 11800b57cec5SDimitry Andric WasmIndices[&WS] = NumGlobalImports++; 11810b57cec5SDimitry Andric } else if (WS.isEvent()) { 11820b57cec5SDimitry Andric if (WS.isWeak()) 11830b57cec5SDimitry Andric report_fatal_error("undefined event symbol cannot be weak"); 11840b57cec5SDimitry Andric 11850b57cec5SDimitry Andric wasm::WasmImport Import; 11860b57cec5SDimitry Andric Import.Module = WS.getImportModule(); 11870b57cec5SDimitry Andric Import.Field = WS.getImportName(); 11880b57cec5SDimitry Andric Import.Kind = wasm::WASM_EXTERNAL_EVENT; 11890b57cec5SDimitry Andric Import.Event.Attribute = wasm::WASM_EVENT_ATTRIBUTE_EXCEPTION; 11900b57cec5SDimitry Andric Import.Event.SigIndex = getEventType(WS); 11910b57cec5SDimitry Andric Imports.push_back(Import); 11920b57cec5SDimitry Andric assert(WasmIndices.count(&WS) == 0); 11930b57cec5SDimitry Andric WasmIndices[&WS] = NumEventImports++; 11940b57cec5SDimitry Andric } 11950b57cec5SDimitry Andric } 11960b57cec5SDimitry Andric } 11970b57cec5SDimitry Andric 11980b57cec5SDimitry Andric // Add imports for GOT globals 11990b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 12000b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 12010b57cec5SDimitry Andric if (WS.isUsedInGOT()) { 12020b57cec5SDimitry Andric wasm::WasmImport Import; 12030b57cec5SDimitry Andric if (WS.isFunction()) 12040b57cec5SDimitry Andric Import.Module = "GOT.func"; 12050b57cec5SDimitry Andric else 12060b57cec5SDimitry Andric Import.Module = "GOT.mem"; 12070b57cec5SDimitry Andric Import.Field = WS.getName(); 12080b57cec5SDimitry Andric Import.Kind = wasm::WASM_EXTERNAL_GLOBAL; 12090b57cec5SDimitry Andric Import.Global = {wasm::WASM_TYPE_I32, true}; 12100b57cec5SDimitry Andric Imports.push_back(Import); 12110b57cec5SDimitry Andric assert(GOTIndices.count(&WS) == 0); 12120b57cec5SDimitry Andric GOTIndices[&WS] = NumGlobalImports++; 12130b57cec5SDimitry Andric } 12140b57cec5SDimitry Andric } 12150b57cec5SDimitry Andric 12160b57cec5SDimitry Andric // Populate DataSegments and CustomSections, which must be done before 12170b57cec5SDimitry Andric // populating DataLocations. 12180b57cec5SDimitry Andric for (MCSection &Sec : Asm) { 12190b57cec5SDimitry Andric auto &Section = static_cast<MCSectionWasm &>(Sec); 12200b57cec5SDimitry Andric StringRef SectionName = Section.getSectionName(); 12210b57cec5SDimitry Andric 12220b57cec5SDimitry Andric // .init_array sections are handled specially elsewhere. 12230b57cec5SDimitry Andric if (SectionName.startswith(".init_array")) 12240b57cec5SDimitry Andric continue; 12250b57cec5SDimitry Andric 12260b57cec5SDimitry Andric // Code is handled separately 12270b57cec5SDimitry Andric if (Section.getKind().isText()) 12280b57cec5SDimitry Andric continue; 12290b57cec5SDimitry Andric 12300b57cec5SDimitry Andric if (Section.isWasmData()) { 12310b57cec5SDimitry Andric uint32_t SegmentIndex = DataSegments.size(); 12320b57cec5SDimitry Andric DataSize = alignTo(DataSize, Section.getAlignment()); 12330b57cec5SDimitry Andric DataSegments.emplace_back(); 12340b57cec5SDimitry Andric WasmDataSegment &Segment = DataSegments.back(); 12350b57cec5SDimitry Andric Segment.Name = SectionName; 12360b57cec5SDimitry Andric Segment.InitFlags = 12370b57cec5SDimitry Andric Section.getPassive() ? (uint32_t)wasm::WASM_SEGMENT_IS_PASSIVE : 0; 12380b57cec5SDimitry Andric Segment.Offset = DataSize; 12390b57cec5SDimitry Andric Segment.Section = &Section; 12400b57cec5SDimitry Andric addData(Segment.Data, Section); 12410b57cec5SDimitry Andric Segment.Alignment = Log2_32(Section.getAlignment()); 12420b57cec5SDimitry Andric Segment.LinkerFlags = 0; 12430b57cec5SDimitry Andric DataSize += Segment.Data.size(); 12440b57cec5SDimitry Andric Section.setSegmentIndex(SegmentIndex); 12450b57cec5SDimitry Andric 12460b57cec5SDimitry Andric if (const MCSymbolWasm *C = Section.getGroup()) { 12470b57cec5SDimitry Andric Comdats[C->getName()].emplace_back( 12480b57cec5SDimitry Andric WasmComdatEntry{wasm::WASM_COMDAT_DATA, SegmentIndex}); 12490b57cec5SDimitry Andric } 12500b57cec5SDimitry Andric } else { 12510b57cec5SDimitry Andric // Create custom sections 12520b57cec5SDimitry Andric assert(Sec.getKind().isMetadata()); 12530b57cec5SDimitry Andric 12540b57cec5SDimitry Andric StringRef Name = SectionName; 12550b57cec5SDimitry Andric 12560b57cec5SDimitry Andric // For user-defined custom sections, strip the prefix 12570b57cec5SDimitry Andric if (Name.startswith(".custom_section.")) 12580b57cec5SDimitry Andric Name = Name.substr(strlen(".custom_section.")); 12590b57cec5SDimitry Andric 12600b57cec5SDimitry Andric MCSymbol *Begin = Sec.getBeginSymbol(); 12610b57cec5SDimitry Andric if (Begin) { 12620b57cec5SDimitry Andric WasmIndices[cast<MCSymbolWasm>(Begin)] = CustomSections.size(); 12630b57cec5SDimitry Andric if (SectionName != Begin->getName()) 12640b57cec5SDimitry Andric report_fatal_error("section name and begin symbol should match: " + 12650b57cec5SDimitry Andric Twine(SectionName)); 12660b57cec5SDimitry Andric } 12670b57cec5SDimitry Andric 12680b57cec5SDimitry Andric // Separate out the producers and target features sections 12690b57cec5SDimitry Andric if (Name == "producers") { 12708bcb0991SDimitry Andric ProducersSection = std::make_unique<WasmCustomSection>(Name, &Section); 12710b57cec5SDimitry Andric continue; 12720b57cec5SDimitry Andric } 12730b57cec5SDimitry Andric if (Name == "target_features") { 12740b57cec5SDimitry Andric TargetFeaturesSection = 12758bcb0991SDimitry Andric std::make_unique<WasmCustomSection>(Name, &Section); 12760b57cec5SDimitry Andric continue; 12770b57cec5SDimitry Andric } 12780b57cec5SDimitry Andric 12790b57cec5SDimitry Andric CustomSections.emplace_back(Name, &Section); 12800b57cec5SDimitry Andric } 12810b57cec5SDimitry Andric } 12820b57cec5SDimitry Andric 12830b57cec5SDimitry Andric // Populate WasmIndices and DataLocations for defined symbols. 12840b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 12850b57cec5SDimitry Andric // Ignore unnamed temporary symbols, which aren't ever exported, imported, 12860b57cec5SDimitry Andric // or used in relocations. 12870b57cec5SDimitry Andric if (S.isTemporary() && S.getName().empty()) 12880b57cec5SDimitry Andric continue; 12890b57cec5SDimitry Andric 12900b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 12910b57cec5SDimitry Andric LLVM_DEBUG( 12920b57cec5SDimitry Andric dbgs() << "MCSymbol: " << toString(WS.getType()) << " '" << S << "'" 12930b57cec5SDimitry Andric << " isDefined=" << S.isDefined() << " isExternal=" 12940b57cec5SDimitry Andric << S.isExternal() << " isTemporary=" << S.isTemporary() 12950b57cec5SDimitry Andric << " isWeak=" << WS.isWeak() << " isHidden=" << WS.isHidden() 12960b57cec5SDimitry Andric << " isVariable=" << WS.isVariable() << "\n"); 12970b57cec5SDimitry Andric 12980b57cec5SDimitry Andric if (WS.isVariable()) 12990b57cec5SDimitry Andric continue; 13000b57cec5SDimitry Andric if (WS.isComdat() && !WS.isDefined()) 13010b57cec5SDimitry Andric continue; 13020b57cec5SDimitry Andric 13030b57cec5SDimitry Andric if (WS.isFunction()) { 13040b57cec5SDimitry Andric unsigned Index; 13050b57cec5SDimitry Andric if (WS.isDefined()) { 13060b57cec5SDimitry Andric if (WS.getOffset() != 0) 13070b57cec5SDimitry Andric report_fatal_error( 13080b57cec5SDimitry Andric "function sections must contain one function each"); 13090b57cec5SDimitry Andric 13100b57cec5SDimitry Andric if (WS.getSize() == nullptr) 13110b57cec5SDimitry Andric report_fatal_error( 13120b57cec5SDimitry Andric "function symbols must have a size set with .size"); 13130b57cec5SDimitry Andric 13140b57cec5SDimitry Andric // A definition. Write out the function body. 13150b57cec5SDimitry Andric Index = NumFunctionImports + Functions.size(); 13160b57cec5SDimitry Andric WasmFunction Func; 13170b57cec5SDimitry Andric Func.SigIndex = getFunctionType(WS); 13180b57cec5SDimitry Andric Func.Sym = &WS; 13190b57cec5SDimitry Andric WasmIndices[&WS] = Index; 13200b57cec5SDimitry Andric Functions.push_back(Func); 13210b57cec5SDimitry Andric 13220b57cec5SDimitry Andric auto &Section = static_cast<MCSectionWasm &>(WS.getSection()); 13230b57cec5SDimitry Andric if (const MCSymbolWasm *C = Section.getGroup()) { 13240b57cec5SDimitry Andric Comdats[C->getName()].emplace_back( 13250b57cec5SDimitry Andric WasmComdatEntry{wasm::WASM_COMDAT_FUNCTION, Index}); 13260b57cec5SDimitry Andric } 1327480093f4SDimitry Andric 1328480093f4SDimitry Andric if (WS.hasExportName()) { 1329480093f4SDimitry Andric wasm::WasmExport Export; 1330480093f4SDimitry Andric Export.Name = WS.getExportName(); 1331480093f4SDimitry Andric Export.Kind = wasm::WASM_EXTERNAL_FUNCTION; 1332480093f4SDimitry Andric Export.Index = Index; 1333480093f4SDimitry Andric Exports.push_back(Export); 1334480093f4SDimitry Andric } 13350b57cec5SDimitry Andric } else { 13360b57cec5SDimitry Andric // An import; the index was assigned above. 13370b57cec5SDimitry Andric Index = WasmIndices.find(&WS)->second; 13380b57cec5SDimitry Andric } 13390b57cec5SDimitry Andric 13400b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> function index: " << Index << "\n"); 13410b57cec5SDimitry Andric 13420b57cec5SDimitry Andric } else if (WS.isData()) { 13430b57cec5SDimitry Andric if (!isInSymtab(WS)) 13440b57cec5SDimitry Andric continue; 13450b57cec5SDimitry Andric 13460b57cec5SDimitry Andric if (!WS.isDefined()) { 13470b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> segment index: -1" 13480b57cec5SDimitry Andric << "\n"); 13490b57cec5SDimitry Andric continue; 13500b57cec5SDimitry Andric } 13510b57cec5SDimitry Andric 13520b57cec5SDimitry Andric if (!WS.getSize()) 13530b57cec5SDimitry Andric report_fatal_error("data symbols must have a size set with .size: " + 13540b57cec5SDimitry Andric WS.getName()); 13550b57cec5SDimitry Andric 13560b57cec5SDimitry Andric int64_t Size = 0; 13570b57cec5SDimitry Andric if (!WS.getSize()->evaluateAsAbsolute(Size, Layout)) 13580b57cec5SDimitry Andric report_fatal_error(".size expression must be evaluatable"); 13590b57cec5SDimitry Andric 13600b57cec5SDimitry Andric auto &DataSection = static_cast<MCSectionWasm &>(WS.getSection()); 13618bcb0991SDimitry Andric if (!DataSection.isWasmData()) 13628bcb0991SDimitry Andric report_fatal_error("data symbols must live in a data section: " + 13638bcb0991SDimitry Andric WS.getName()); 13640b57cec5SDimitry Andric 13650b57cec5SDimitry Andric // For each data symbol, export it in the symtab as a reference to the 13660b57cec5SDimitry Andric // corresponding Wasm data segment. 13670b57cec5SDimitry Andric wasm::WasmDataReference Ref = wasm::WasmDataReference{ 13680b57cec5SDimitry Andric DataSection.getSegmentIndex(), 13690b57cec5SDimitry Andric static_cast<uint32_t>(Layout.getSymbolOffset(WS)), 13700b57cec5SDimitry Andric static_cast<uint32_t>(Size)}; 13710b57cec5SDimitry Andric DataLocations[&WS] = Ref; 13720b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> segment index: " << Ref.Segment << "\n"); 13730b57cec5SDimitry Andric 13740b57cec5SDimitry Andric } else if (WS.isGlobal()) { 13750b57cec5SDimitry Andric // A "true" Wasm global (currently just __stack_pointer) 13760b57cec5SDimitry Andric if (WS.isDefined()) 13770b57cec5SDimitry Andric report_fatal_error("don't yet support defined globals"); 13780b57cec5SDimitry Andric 13790b57cec5SDimitry Andric // An import; the index was assigned above 13800b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> global index: " 13810b57cec5SDimitry Andric << WasmIndices.find(&WS)->second << "\n"); 13820b57cec5SDimitry Andric 13830b57cec5SDimitry Andric } else if (WS.isEvent()) { 13840b57cec5SDimitry Andric // C++ exception symbol (__cpp_exception) 13850b57cec5SDimitry Andric unsigned Index; 13860b57cec5SDimitry Andric if (WS.isDefined()) { 13870b57cec5SDimitry Andric Index = NumEventImports + Events.size(); 13880b57cec5SDimitry Andric wasm::WasmEventType Event; 13890b57cec5SDimitry Andric Event.SigIndex = getEventType(WS); 13900b57cec5SDimitry Andric Event.Attribute = wasm::WASM_EVENT_ATTRIBUTE_EXCEPTION; 13910b57cec5SDimitry Andric assert(WasmIndices.count(&WS) == 0); 13920b57cec5SDimitry Andric WasmIndices[&WS] = Index; 13930b57cec5SDimitry Andric Events.push_back(Event); 13940b57cec5SDimitry Andric } else { 13950b57cec5SDimitry Andric // An import; the index was assigned above. 13960b57cec5SDimitry Andric assert(WasmIndices.count(&WS) > 0); 13970b57cec5SDimitry Andric } 13980b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> event index: " << WasmIndices.find(&WS)->second 13990b57cec5SDimitry Andric << "\n"); 14000b57cec5SDimitry Andric 14010b57cec5SDimitry Andric } else { 14020b57cec5SDimitry Andric assert(WS.isSection()); 14030b57cec5SDimitry Andric } 14040b57cec5SDimitry Andric } 14050b57cec5SDimitry Andric 14060b57cec5SDimitry Andric // Populate WasmIndices and DataLocations for aliased symbols. We need to 14070b57cec5SDimitry Andric // process these in a separate pass because we need to have processed the 14080b57cec5SDimitry Andric // target of the alias before the alias itself and the symbols are not 14090b57cec5SDimitry Andric // necessarily ordered in this way. 14100b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 14110b57cec5SDimitry Andric if (!S.isVariable()) 14120b57cec5SDimitry Andric continue; 14130b57cec5SDimitry Andric 14140b57cec5SDimitry Andric assert(S.isDefined()); 14150b57cec5SDimitry Andric 14160b57cec5SDimitry Andric // Find the target symbol of this weak alias and export that index 14170b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 14180b57cec5SDimitry Andric const MCSymbolWasm *ResolvedSym = resolveSymbol(WS); 14190b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << WS.getName() << ": weak alias of '" << *ResolvedSym 14200b57cec5SDimitry Andric << "'\n"); 14210b57cec5SDimitry Andric 14220b57cec5SDimitry Andric if (ResolvedSym->isFunction()) { 14230b57cec5SDimitry Andric assert(WasmIndices.count(ResolvedSym) > 0); 14240b57cec5SDimitry Andric uint32_t WasmIndex = WasmIndices.find(ResolvedSym)->second; 14250b57cec5SDimitry Andric assert(WasmIndices.count(&WS) == 0); 14260b57cec5SDimitry Andric WasmIndices[&WS] = WasmIndex; 14270b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> index:" << WasmIndex << "\n"); 14280b57cec5SDimitry Andric } else if (ResolvedSym->isData()) { 14290b57cec5SDimitry Andric assert(DataLocations.count(ResolvedSym) > 0); 14300b57cec5SDimitry Andric const wasm::WasmDataReference &Ref = 14310b57cec5SDimitry Andric DataLocations.find(ResolvedSym)->second; 14320b57cec5SDimitry Andric DataLocations[&WS] = Ref; 14330b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> index:" << Ref.Segment << "\n"); 14340b57cec5SDimitry Andric } else { 14350b57cec5SDimitry Andric report_fatal_error("don't yet support global/event aliases"); 14360b57cec5SDimitry Andric } 14370b57cec5SDimitry Andric } 14380b57cec5SDimitry Andric 14390b57cec5SDimitry Andric // Finally, populate the symbol table itself, in its "natural" order. 14400b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 14410b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 14420b57cec5SDimitry Andric if (!isInSymtab(WS)) { 14430b57cec5SDimitry Andric WS.setIndex(InvalidIndex); 14440b57cec5SDimitry Andric continue; 14450b57cec5SDimitry Andric } 14460b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "adding to symtab: " << WS << "\n"); 14470b57cec5SDimitry Andric 14480b57cec5SDimitry Andric uint32_t Flags = 0; 14490b57cec5SDimitry Andric if (WS.isWeak()) 14500b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_BINDING_WEAK; 14510b57cec5SDimitry Andric if (WS.isHidden()) 14520b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_VISIBILITY_HIDDEN; 14530b57cec5SDimitry Andric if (!WS.isExternal() && WS.isDefined()) 14540b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_BINDING_LOCAL; 14550b57cec5SDimitry Andric if (WS.isUndefined()) 14560b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_UNDEFINED; 14578bcb0991SDimitry Andric if (WS.isNoStrip()) { 14588bcb0991SDimitry Andric Flags |= wasm::WASM_SYMBOL_NO_STRIP; 14598bcb0991SDimitry Andric if (isEmscripten()) { 14600b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_EXPORTED; 14618bcb0991SDimitry Andric } 14628bcb0991SDimitry Andric } 1463480093f4SDimitry Andric if (WS.hasImportName()) 14640b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_EXPLICIT_NAME; 1465480093f4SDimitry Andric if (WS.hasExportName()) 1466480093f4SDimitry Andric Flags |= wasm::WASM_SYMBOL_EXPORTED; 14670b57cec5SDimitry Andric 14680b57cec5SDimitry Andric wasm::WasmSymbolInfo Info; 14690b57cec5SDimitry Andric Info.Name = WS.getName(); 14700b57cec5SDimitry Andric Info.Kind = WS.getType(); 14710b57cec5SDimitry Andric Info.Flags = Flags; 14720b57cec5SDimitry Andric if (!WS.isData()) { 14730b57cec5SDimitry Andric assert(WasmIndices.count(&WS) > 0); 14740b57cec5SDimitry Andric Info.ElementIndex = WasmIndices.find(&WS)->second; 14750b57cec5SDimitry Andric } else if (WS.isDefined()) { 14760b57cec5SDimitry Andric assert(DataLocations.count(&WS) > 0); 14770b57cec5SDimitry Andric Info.DataRef = DataLocations.find(&WS)->second; 14780b57cec5SDimitry Andric } 14790b57cec5SDimitry Andric WS.setIndex(SymbolInfos.size()); 14800b57cec5SDimitry Andric SymbolInfos.emplace_back(Info); 14810b57cec5SDimitry Andric } 14820b57cec5SDimitry Andric 14830b57cec5SDimitry Andric { 14840b57cec5SDimitry Andric auto HandleReloc = [&](const WasmRelocationEntry &Rel) { 14850b57cec5SDimitry Andric // Functions referenced by a relocation need to put in the table. This is 14860b57cec5SDimitry Andric // purely to make the object file's provisional values readable, and is 14870b57cec5SDimitry Andric // ignored by the linker, which re-calculates the relocations itself. 14880b57cec5SDimitry Andric if (Rel.Type != wasm::R_WASM_TABLE_INDEX_I32 && 14890b57cec5SDimitry Andric Rel.Type != wasm::R_WASM_TABLE_INDEX_SLEB) 14900b57cec5SDimitry Andric return; 14910b57cec5SDimitry Andric assert(Rel.Symbol->isFunction()); 14920b57cec5SDimitry Andric const MCSymbolWasm &WS = *resolveSymbol(*Rel.Symbol); 14930b57cec5SDimitry Andric uint32_t FunctionIndex = WasmIndices.find(&WS)->second; 14940b57cec5SDimitry Andric uint32_t TableIndex = TableElems.size() + InitialTableOffset; 14950b57cec5SDimitry Andric if (TableIndices.try_emplace(&WS, TableIndex).second) { 14960b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> adding " << WS.getName() 14970b57cec5SDimitry Andric << " to table: " << TableIndex << "\n"); 14980b57cec5SDimitry Andric TableElems.push_back(FunctionIndex); 14990b57cec5SDimitry Andric registerFunctionType(WS); 15000b57cec5SDimitry Andric } 15010b57cec5SDimitry Andric }; 15020b57cec5SDimitry Andric 15030b57cec5SDimitry Andric for (const WasmRelocationEntry &RelEntry : CodeRelocations) 15040b57cec5SDimitry Andric HandleReloc(RelEntry); 15050b57cec5SDimitry Andric for (const WasmRelocationEntry &RelEntry : DataRelocations) 15060b57cec5SDimitry Andric HandleReloc(RelEntry); 15070b57cec5SDimitry Andric } 15080b57cec5SDimitry Andric 15090b57cec5SDimitry Andric // Translate .init_array section contents into start functions. 15100b57cec5SDimitry Andric for (const MCSection &S : Asm) { 15110b57cec5SDimitry Andric const auto &WS = static_cast<const MCSectionWasm &>(S); 15120b57cec5SDimitry Andric if (WS.getSectionName().startswith(".fini_array")) 15130b57cec5SDimitry Andric report_fatal_error(".fini_array sections are unsupported"); 15140b57cec5SDimitry Andric if (!WS.getSectionName().startswith(".init_array")) 15150b57cec5SDimitry Andric continue; 15160b57cec5SDimitry Andric if (WS.getFragmentList().empty()) 15170b57cec5SDimitry Andric continue; 15180b57cec5SDimitry Andric 15190b57cec5SDimitry Andric // init_array is expected to contain a single non-empty data fragment 15200b57cec5SDimitry Andric if (WS.getFragmentList().size() != 3) 15210b57cec5SDimitry Andric report_fatal_error("only one .init_array section fragment supported"); 15220b57cec5SDimitry Andric 15230b57cec5SDimitry Andric auto IT = WS.begin(); 15240b57cec5SDimitry Andric const MCFragment &EmptyFrag = *IT; 15250b57cec5SDimitry Andric if (EmptyFrag.getKind() != MCFragment::FT_Data) 15260b57cec5SDimitry Andric report_fatal_error(".init_array section should be aligned"); 15270b57cec5SDimitry Andric 15280b57cec5SDimitry Andric IT = std::next(IT); 15290b57cec5SDimitry Andric const MCFragment &AlignFrag = *IT; 15300b57cec5SDimitry Andric if (AlignFrag.getKind() != MCFragment::FT_Align) 15310b57cec5SDimitry Andric report_fatal_error(".init_array section should be aligned"); 15320b57cec5SDimitry Andric if (cast<MCAlignFragment>(AlignFrag).getAlignment() != (is64Bit() ? 8 : 4)) 15330b57cec5SDimitry Andric report_fatal_error(".init_array section should be aligned for pointers"); 15340b57cec5SDimitry Andric 15350b57cec5SDimitry Andric const MCFragment &Frag = *std::next(IT); 15360b57cec5SDimitry Andric if (Frag.hasInstructions() || Frag.getKind() != MCFragment::FT_Data) 15370b57cec5SDimitry Andric report_fatal_error("only data supported in .init_array section"); 15380b57cec5SDimitry Andric 15390b57cec5SDimitry Andric uint16_t Priority = UINT16_MAX; 15400b57cec5SDimitry Andric unsigned PrefixLength = strlen(".init_array"); 15410b57cec5SDimitry Andric if (WS.getSectionName().size() > PrefixLength) { 15420b57cec5SDimitry Andric if (WS.getSectionName()[PrefixLength] != '.') 15430b57cec5SDimitry Andric report_fatal_error( 15440b57cec5SDimitry Andric ".init_array section priority should start with '.'"); 15450b57cec5SDimitry Andric if (WS.getSectionName() 15460b57cec5SDimitry Andric .substr(PrefixLength + 1) 15470b57cec5SDimitry Andric .getAsInteger(10, Priority)) 15480b57cec5SDimitry Andric report_fatal_error("invalid .init_array section priority"); 15490b57cec5SDimitry Andric } 15500b57cec5SDimitry Andric const auto &DataFrag = cast<MCDataFragment>(Frag); 15510b57cec5SDimitry Andric const SmallVectorImpl<char> &Contents = DataFrag.getContents(); 15520b57cec5SDimitry Andric for (const uint8_t * 15530b57cec5SDimitry Andric P = (const uint8_t *)Contents.data(), 15540b57cec5SDimitry Andric *End = (const uint8_t *)Contents.data() + Contents.size(); 15550b57cec5SDimitry Andric P != End; ++P) { 15560b57cec5SDimitry Andric if (*P != 0) 15570b57cec5SDimitry Andric report_fatal_error("non-symbolic data in .init_array section"); 15580b57cec5SDimitry Andric } 15590b57cec5SDimitry Andric for (const MCFixup &Fixup : DataFrag.getFixups()) { 15600b57cec5SDimitry Andric assert(Fixup.getKind() == 15610b57cec5SDimitry Andric MCFixup::getKindForSize(is64Bit() ? 8 : 4, false)); 15620b57cec5SDimitry Andric const MCExpr *Expr = Fixup.getValue(); 15630b57cec5SDimitry Andric auto *SymRef = dyn_cast<MCSymbolRefExpr>(Expr); 15640b57cec5SDimitry Andric if (!SymRef) 15650b57cec5SDimitry Andric report_fatal_error("fixups in .init_array should be symbol references"); 15660b57cec5SDimitry Andric const auto &TargetSym = cast<const MCSymbolWasm>(SymRef->getSymbol()); 15670b57cec5SDimitry Andric if (TargetSym.getIndex() == InvalidIndex) 15680b57cec5SDimitry Andric report_fatal_error("symbols in .init_array should exist in symbtab"); 15690b57cec5SDimitry Andric if (!TargetSym.isFunction()) 15700b57cec5SDimitry Andric report_fatal_error("symbols in .init_array should be for functions"); 15710b57cec5SDimitry Andric InitFuncs.push_back( 15720b57cec5SDimitry Andric std::make_pair(Priority, TargetSym.getIndex())); 15730b57cec5SDimitry Andric } 15740b57cec5SDimitry Andric } 15750b57cec5SDimitry Andric 15760b57cec5SDimitry Andric // Write out the Wasm header. 15770b57cec5SDimitry Andric writeHeader(Asm); 15780b57cec5SDimitry Andric 15790b57cec5SDimitry Andric writeTypeSection(Signatures); 15800b57cec5SDimitry Andric writeImportSection(Imports, DataSize, TableElems.size()); 15810b57cec5SDimitry Andric writeFunctionSection(Functions); 15820b57cec5SDimitry Andric // Skip the "table" section; we import the table instead. 15830b57cec5SDimitry Andric // Skip the "memory" section; we import the memory instead. 15840b57cec5SDimitry Andric writeEventSection(Events); 15850b57cec5SDimitry Andric writeExportSection(Exports); 15860b57cec5SDimitry Andric writeElemSection(TableElems); 15870b57cec5SDimitry Andric writeDataCountSection(); 15880b57cec5SDimitry Andric writeCodeSection(Asm, Layout, Functions); 15890b57cec5SDimitry Andric writeDataSection(); 15900b57cec5SDimitry Andric for (auto &CustomSection : CustomSections) 15910b57cec5SDimitry Andric writeCustomSection(CustomSection, Asm, Layout); 15920b57cec5SDimitry Andric writeLinkingMetaDataSection(SymbolInfos, InitFuncs, Comdats); 15930b57cec5SDimitry Andric writeRelocSection(CodeSectionIndex, "CODE", CodeRelocations); 15940b57cec5SDimitry Andric writeRelocSection(DataSectionIndex, "DATA", DataRelocations); 15950b57cec5SDimitry Andric writeCustomRelocSections(); 15960b57cec5SDimitry Andric if (ProducersSection) 15970b57cec5SDimitry Andric writeCustomSection(*ProducersSection, Asm, Layout); 15980b57cec5SDimitry Andric if (TargetFeaturesSection) 15990b57cec5SDimitry Andric writeCustomSection(*TargetFeaturesSection, Asm, Layout); 16000b57cec5SDimitry Andric 16010b57cec5SDimitry Andric // TODO: Translate the .comment section to the output. 16020b57cec5SDimitry Andric return W.OS.tell() - StartOffset; 16030b57cec5SDimitry Andric } 16040b57cec5SDimitry Andric 16050b57cec5SDimitry Andric std::unique_ptr<MCObjectWriter> 16060b57cec5SDimitry Andric llvm::createWasmObjectWriter(std::unique_ptr<MCWasmObjectTargetWriter> MOTW, 16070b57cec5SDimitry Andric raw_pwrite_stream &OS) { 16088bcb0991SDimitry Andric return std::make_unique<WasmObjectWriter>(std::move(MOTW), OS); 16090b57cec5SDimitry Andric } 1610