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" 16e8d8bef9SDimitry Andric #include "llvm/BinaryFormat/WasmTraits.h" 170b57cec5SDimitry Andric #include "llvm/Config/llvm-config.h" 180b57cec5SDimitry Andric #include "llvm/MC/MCAsmBackend.h" 190b57cec5SDimitry Andric #include "llvm/MC/MCAsmLayout.h" 200b57cec5SDimitry Andric #include "llvm/MC/MCAssembler.h" 210b57cec5SDimitry Andric #include "llvm/MC/MCContext.h" 220b57cec5SDimitry Andric #include "llvm/MC/MCExpr.h" 230b57cec5SDimitry Andric #include "llvm/MC/MCFixupKindInfo.h" 240b57cec5SDimitry Andric #include "llvm/MC/MCObjectWriter.h" 250b57cec5SDimitry Andric #include "llvm/MC/MCSectionWasm.h" 260b57cec5SDimitry Andric #include "llvm/MC/MCSymbolWasm.h" 270b57cec5SDimitry Andric #include "llvm/MC/MCValue.h" 280b57cec5SDimitry Andric #include "llvm/MC/MCWasmObjectWriter.h" 290b57cec5SDimitry Andric #include "llvm/Support/Casting.h" 300b57cec5SDimitry Andric #include "llvm/Support/Debug.h" 315ffd83dbSDimitry Andric #include "llvm/Support/EndianStream.h" 320b57cec5SDimitry Andric #include "llvm/Support/ErrorHandling.h" 330b57cec5SDimitry Andric #include "llvm/Support/LEB128.h" 340b57cec5SDimitry Andric #include "llvm/Support/StringSaver.h" 350b57cec5SDimitry Andric #include <vector> 360b57cec5SDimitry Andric 370b57cec5SDimitry Andric using namespace llvm; 380b57cec5SDimitry Andric 390b57cec5SDimitry Andric #define DEBUG_TYPE "mc" 400b57cec5SDimitry Andric 410b57cec5SDimitry Andric namespace { 420b57cec5SDimitry Andric 43e8d8bef9SDimitry Andric // When we create the indirect function table we start at 1, so that there is 44e8d8bef9SDimitry Andric // and empty slot at 0 and therefore calling a null function pointer will trap. 450b57cec5SDimitry Andric static const uint32_t InitialTableOffset = 1; 460b57cec5SDimitry Andric 470b57cec5SDimitry Andric // For patching purposes, we need to remember where each section starts, both 480b57cec5SDimitry Andric // for patching up the section size field, and for patching up references to 490b57cec5SDimitry Andric // locations within the section. 500b57cec5SDimitry Andric struct SectionBookkeeping { 510b57cec5SDimitry Andric // Where the size of the section is written. 520b57cec5SDimitry Andric uint64_t SizeOffset; 530b57cec5SDimitry Andric // Where the section header ends (without custom section name). 540b57cec5SDimitry Andric uint64_t PayloadOffset; 550b57cec5SDimitry Andric // Where the contents of the section starts. 560b57cec5SDimitry Andric uint64_t ContentsOffset; 570b57cec5SDimitry Andric uint32_t Index; 580b57cec5SDimitry Andric }; 590b57cec5SDimitry Andric 600b57cec5SDimitry Andric // A wasm data segment. A wasm binary contains only a single data section 610b57cec5SDimitry Andric // but that can contain many segments, each with their own virtual location 620b57cec5SDimitry Andric // in memory. Each MCSection data created by llvm is modeled as its own 630b57cec5SDimitry Andric // wasm data segment. 640b57cec5SDimitry Andric struct WasmDataSegment { 650b57cec5SDimitry Andric MCSectionWasm *Section; 660b57cec5SDimitry Andric StringRef Name; 670b57cec5SDimitry Andric uint32_t InitFlags; 685ffd83dbSDimitry Andric uint64_t Offset; 690b57cec5SDimitry Andric uint32_t Alignment; 700b57cec5SDimitry Andric uint32_t LinkerFlags; 710b57cec5SDimitry Andric SmallVector<char, 4> Data; 720b57cec5SDimitry Andric }; 730b57cec5SDimitry Andric 740b57cec5SDimitry Andric // A wasm function to be written into the function section. 750b57cec5SDimitry Andric struct WasmFunction { 760b57cec5SDimitry Andric uint32_t SigIndex; 770b57cec5SDimitry Andric const MCSymbolWasm *Sym; 780b57cec5SDimitry Andric }; 790b57cec5SDimitry Andric 800b57cec5SDimitry Andric // A wasm global to be written into the global section. 810b57cec5SDimitry Andric struct WasmGlobal { 820b57cec5SDimitry Andric wasm::WasmGlobalType Type; 830b57cec5SDimitry Andric uint64_t InitialValue; 840b57cec5SDimitry Andric }; 850b57cec5SDimitry Andric 860b57cec5SDimitry Andric // Information about a single item which is part of a COMDAT. For each data 870b57cec5SDimitry Andric // segment or function which is in the COMDAT, there is a corresponding 880b57cec5SDimitry Andric // WasmComdatEntry. 890b57cec5SDimitry Andric struct WasmComdatEntry { 900b57cec5SDimitry Andric unsigned Kind; 910b57cec5SDimitry Andric uint32_t Index; 920b57cec5SDimitry Andric }; 930b57cec5SDimitry Andric 940b57cec5SDimitry Andric // Information about a single relocation. 950b57cec5SDimitry Andric struct WasmRelocationEntry { 960b57cec5SDimitry Andric uint64_t Offset; // Where is the relocation. 970b57cec5SDimitry Andric const MCSymbolWasm *Symbol; // The symbol to relocate with. 980b57cec5SDimitry Andric int64_t Addend; // A value to add to the symbol. 990b57cec5SDimitry Andric unsigned Type; // The type of the relocation. 1000b57cec5SDimitry Andric const MCSectionWasm *FixupSection; // The section the relocation is targeting. 1010b57cec5SDimitry Andric 1020b57cec5SDimitry Andric WasmRelocationEntry(uint64_t Offset, const MCSymbolWasm *Symbol, 1030b57cec5SDimitry Andric int64_t Addend, unsigned Type, 1040b57cec5SDimitry Andric const MCSectionWasm *FixupSection) 1050b57cec5SDimitry Andric : Offset(Offset), Symbol(Symbol), Addend(Addend), Type(Type), 1060b57cec5SDimitry Andric FixupSection(FixupSection) {} 1070b57cec5SDimitry Andric 1080b57cec5SDimitry Andric bool hasAddend() const { return wasm::relocTypeHasAddend(Type); } 1090b57cec5SDimitry Andric 1100b57cec5SDimitry Andric void print(raw_ostream &Out) const { 1110b57cec5SDimitry Andric Out << wasm::relocTypetoString(Type) << " Off=" << Offset 1120b57cec5SDimitry Andric << ", Sym=" << *Symbol << ", Addend=" << Addend 1135ffd83dbSDimitry Andric << ", FixupSection=" << FixupSection->getName(); 1140b57cec5SDimitry Andric } 1150b57cec5SDimitry Andric 1160b57cec5SDimitry Andric #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 1170b57cec5SDimitry Andric LLVM_DUMP_METHOD void dump() const { print(dbgs()); } 1180b57cec5SDimitry Andric #endif 1190b57cec5SDimitry Andric }; 1200b57cec5SDimitry Andric 1210b57cec5SDimitry Andric static const uint32_t InvalidIndex = -1; 1220b57cec5SDimitry Andric 1230b57cec5SDimitry Andric struct WasmCustomSection { 1240b57cec5SDimitry Andric 1250b57cec5SDimitry Andric StringRef Name; 1260b57cec5SDimitry Andric MCSectionWasm *Section; 1270b57cec5SDimitry Andric 1280b57cec5SDimitry Andric uint32_t OutputContentsOffset; 1290b57cec5SDimitry Andric uint32_t OutputIndex; 1300b57cec5SDimitry Andric 1310b57cec5SDimitry Andric WasmCustomSection(StringRef Name, MCSectionWasm *Section) 1320b57cec5SDimitry Andric : Name(Name), Section(Section), OutputContentsOffset(0), 1330b57cec5SDimitry Andric OutputIndex(InvalidIndex) {} 1340b57cec5SDimitry Andric }; 1350b57cec5SDimitry Andric 1360b57cec5SDimitry Andric #if !defined(NDEBUG) 1370b57cec5SDimitry Andric raw_ostream &operator<<(raw_ostream &OS, const WasmRelocationEntry &Rel) { 1380b57cec5SDimitry Andric Rel.print(OS); 1390b57cec5SDimitry Andric return OS; 1400b57cec5SDimitry Andric } 1410b57cec5SDimitry Andric #endif 1420b57cec5SDimitry Andric 1430b57cec5SDimitry Andric // Write X as an (unsigned) LEB value at offset Offset in Stream, padded 1440b57cec5SDimitry Andric // to allow patching. 1455ffd83dbSDimitry Andric template <int W> 1465ffd83dbSDimitry Andric void writePatchableLEB(raw_pwrite_stream &Stream, uint64_t X, uint64_t Offset) { 1475ffd83dbSDimitry Andric uint8_t Buffer[W]; 1485ffd83dbSDimitry Andric unsigned SizeLen = encodeULEB128(X, Buffer, W); 1495ffd83dbSDimitry Andric assert(SizeLen == W); 1500b57cec5SDimitry Andric Stream.pwrite((char *)Buffer, SizeLen, Offset); 1510b57cec5SDimitry Andric } 1520b57cec5SDimitry Andric 1530b57cec5SDimitry Andric // Write X as an signed LEB value at offset Offset in Stream, padded 1540b57cec5SDimitry Andric // to allow patching. 1555ffd83dbSDimitry Andric template <int W> 1565ffd83dbSDimitry Andric void writePatchableSLEB(raw_pwrite_stream &Stream, int64_t X, uint64_t Offset) { 1575ffd83dbSDimitry Andric uint8_t Buffer[W]; 1585ffd83dbSDimitry Andric unsigned SizeLen = encodeSLEB128(X, Buffer, W); 1595ffd83dbSDimitry Andric assert(SizeLen == W); 1600b57cec5SDimitry Andric Stream.pwrite((char *)Buffer, SizeLen, Offset); 1610b57cec5SDimitry Andric } 1620b57cec5SDimitry Andric 1630b57cec5SDimitry Andric // Write X as a plain integer value at offset Offset in Stream. 1645ffd83dbSDimitry Andric static void patchI32(raw_pwrite_stream &Stream, uint32_t X, uint64_t Offset) { 1650b57cec5SDimitry Andric uint8_t Buffer[4]; 1660b57cec5SDimitry Andric support::endian::write32le(Buffer, X); 1670b57cec5SDimitry Andric Stream.pwrite((char *)Buffer, sizeof(Buffer), Offset); 1680b57cec5SDimitry Andric } 1690b57cec5SDimitry Andric 1705ffd83dbSDimitry Andric static void patchI64(raw_pwrite_stream &Stream, uint64_t X, uint64_t Offset) { 1715ffd83dbSDimitry Andric uint8_t Buffer[8]; 1725ffd83dbSDimitry Andric support::endian::write64le(Buffer, X); 1735ffd83dbSDimitry Andric Stream.pwrite((char *)Buffer, sizeof(Buffer), Offset); 1745ffd83dbSDimitry Andric } 1755ffd83dbSDimitry Andric 176e8d8bef9SDimitry Andric bool isDwoSection(const MCSection &Sec) { 177e8d8bef9SDimitry Andric return Sec.getName().endswith(".dwo"); 178e8d8bef9SDimitry Andric } 179e8d8bef9SDimitry Andric 1800b57cec5SDimitry Andric class WasmObjectWriter : public MCObjectWriter { 181e8d8bef9SDimitry Andric support::endian::Writer *W; 1820b57cec5SDimitry Andric 1830b57cec5SDimitry Andric /// The target specific Wasm writer instance. 1840b57cec5SDimitry Andric std::unique_ptr<MCWasmObjectTargetWriter> TargetObjectWriter; 1850b57cec5SDimitry Andric 1860b57cec5SDimitry Andric // Relocations for fixing up references in the code section. 1870b57cec5SDimitry Andric std::vector<WasmRelocationEntry> CodeRelocations; 1880b57cec5SDimitry Andric // Relocations for fixing up references in the data section. 1890b57cec5SDimitry Andric std::vector<WasmRelocationEntry> DataRelocations; 1900b57cec5SDimitry Andric 1910b57cec5SDimitry Andric // Index values to use for fixing up call_indirect type indices. 1920b57cec5SDimitry Andric // Maps function symbols to the index of the type of the function 1930b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, uint32_t> TypeIndices; 1940b57cec5SDimitry Andric // Maps function symbols to the table element index space. Used 1950b57cec5SDimitry Andric // for TABLE_INDEX relocation types (i.e. address taken functions). 1960b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, uint32_t> TableIndices; 197e8d8bef9SDimitry Andric // Maps function/global/table symbols to the 198e8d8bef9SDimitry Andric // function/global/table/event/section index space. 1990b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, uint32_t> WasmIndices; 2000b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, uint32_t> GOTIndices; 2010b57cec5SDimitry Andric // Maps data symbols to the Wasm segment and offset/size with the segment. 2020b57cec5SDimitry Andric DenseMap<const MCSymbolWasm *, wasm::WasmDataReference> DataLocations; 2030b57cec5SDimitry Andric 2040b57cec5SDimitry Andric // Stores output data (index, relocations, content offset) for custom 2050b57cec5SDimitry Andric // section. 2060b57cec5SDimitry Andric std::vector<WasmCustomSection> CustomSections; 2070b57cec5SDimitry Andric std::unique_ptr<WasmCustomSection> ProducersSection; 2080b57cec5SDimitry Andric std::unique_ptr<WasmCustomSection> TargetFeaturesSection; 2090b57cec5SDimitry Andric // Relocations for fixing up references in the custom sections. 2100b57cec5SDimitry Andric DenseMap<const MCSectionWasm *, std::vector<WasmRelocationEntry>> 2110b57cec5SDimitry Andric CustomSectionsRelocations; 2120b57cec5SDimitry Andric 2130b57cec5SDimitry Andric // Map from section to defining function symbol. 2140b57cec5SDimitry Andric DenseMap<const MCSection *, const MCSymbol *> SectionFunctions; 2150b57cec5SDimitry Andric 216e8d8bef9SDimitry Andric DenseMap<wasm::WasmSignature, uint32_t> SignatureIndices; 217e8d8bef9SDimitry Andric SmallVector<wasm::WasmSignature, 4> Signatures; 2180b57cec5SDimitry Andric SmallVector<WasmDataSegment, 4> DataSegments; 2190b57cec5SDimitry Andric unsigned NumFunctionImports = 0; 2200b57cec5SDimitry Andric unsigned NumGlobalImports = 0; 221e8d8bef9SDimitry Andric unsigned NumTableImports = 0; 2220b57cec5SDimitry Andric unsigned NumEventImports = 0; 2230b57cec5SDimitry Andric uint32_t SectionCount = 0; 2240b57cec5SDimitry Andric 225e8d8bef9SDimitry Andric enum class DwoMode { 226e8d8bef9SDimitry Andric AllSections, 227e8d8bef9SDimitry Andric NonDwoOnly, 228e8d8bef9SDimitry Andric DwoOnly, 229e8d8bef9SDimitry Andric }; 230e8d8bef9SDimitry Andric bool IsSplitDwarf = false; 231e8d8bef9SDimitry Andric raw_pwrite_stream *OS = nullptr; 232e8d8bef9SDimitry Andric raw_pwrite_stream *DwoOS = nullptr; 233e8d8bef9SDimitry Andric 234e8d8bef9SDimitry Andric // TargetObjectWriter wranppers. 2350b57cec5SDimitry Andric bool is64Bit() const { return TargetObjectWriter->is64Bit(); } 2368bcb0991SDimitry Andric bool isEmscripten() const { return TargetObjectWriter->isEmscripten(); } 2370b57cec5SDimitry Andric 2380b57cec5SDimitry Andric void startSection(SectionBookkeeping &Section, unsigned SectionId); 2390b57cec5SDimitry Andric void startCustomSection(SectionBookkeeping &Section, StringRef Name); 2400b57cec5SDimitry Andric void endSection(SectionBookkeeping &Section); 2410b57cec5SDimitry Andric 2420b57cec5SDimitry Andric public: 2430b57cec5SDimitry Andric WasmObjectWriter(std::unique_ptr<MCWasmObjectTargetWriter> MOTW, 244e8d8bef9SDimitry Andric raw_pwrite_stream &OS_) 245e8d8bef9SDimitry Andric : TargetObjectWriter(std::move(MOTW)), OS(&OS_) {} 246e8d8bef9SDimitry Andric 247e8d8bef9SDimitry Andric WasmObjectWriter(std::unique_ptr<MCWasmObjectTargetWriter> MOTW, 248e8d8bef9SDimitry Andric raw_pwrite_stream &OS_, raw_pwrite_stream &DwoOS_) 249e8d8bef9SDimitry Andric : TargetObjectWriter(std::move(MOTW)), IsSplitDwarf(true), OS(&OS_), 250e8d8bef9SDimitry Andric DwoOS(&DwoOS_) {} 2510b57cec5SDimitry Andric 2520b57cec5SDimitry Andric private: 2530b57cec5SDimitry Andric void reset() override { 2540b57cec5SDimitry Andric CodeRelocations.clear(); 2550b57cec5SDimitry Andric DataRelocations.clear(); 2560b57cec5SDimitry Andric TypeIndices.clear(); 2570b57cec5SDimitry Andric WasmIndices.clear(); 2580b57cec5SDimitry Andric GOTIndices.clear(); 2590b57cec5SDimitry Andric TableIndices.clear(); 2600b57cec5SDimitry Andric DataLocations.clear(); 2610b57cec5SDimitry Andric CustomSections.clear(); 2620b57cec5SDimitry Andric ProducersSection.reset(); 2630b57cec5SDimitry Andric TargetFeaturesSection.reset(); 2640b57cec5SDimitry Andric CustomSectionsRelocations.clear(); 2650b57cec5SDimitry Andric SignatureIndices.clear(); 2660b57cec5SDimitry Andric Signatures.clear(); 2670b57cec5SDimitry Andric DataSegments.clear(); 2680b57cec5SDimitry Andric SectionFunctions.clear(); 2690b57cec5SDimitry Andric NumFunctionImports = 0; 2700b57cec5SDimitry Andric NumGlobalImports = 0; 271e8d8bef9SDimitry Andric NumTableImports = 0; 2720b57cec5SDimitry Andric MCObjectWriter::reset(); 2730b57cec5SDimitry Andric } 2740b57cec5SDimitry Andric 2750b57cec5SDimitry Andric void writeHeader(const MCAssembler &Asm); 2760b57cec5SDimitry Andric 2770b57cec5SDimitry Andric void recordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout, 2780b57cec5SDimitry Andric const MCFragment *Fragment, const MCFixup &Fixup, 2790b57cec5SDimitry Andric MCValue Target, uint64_t &FixedValue) override; 2800b57cec5SDimitry Andric 2810b57cec5SDimitry Andric void executePostLayoutBinding(MCAssembler &Asm, 2820b57cec5SDimitry Andric const MCAsmLayout &Layout) override; 283e8d8bef9SDimitry Andric void prepareImports(SmallVectorImpl<wasm::WasmImport> &Imports, 284e8d8bef9SDimitry Andric MCAssembler &Asm, const MCAsmLayout &Layout); 2850b57cec5SDimitry Andric uint64_t writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override; 2860b57cec5SDimitry Andric 287e8d8bef9SDimitry Andric uint64_t writeOneObject(MCAssembler &Asm, const MCAsmLayout &Layout, 288e8d8bef9SDimitry Andric DwoMode Mode); 289e8d8bef9SDimitry Andric 2900b57cec5SDimitry Andric void writeString(const StringRef Str) { 291e8d8bef9SDimitry Andric encodeULEB128(Str.size(), W->OS); 292e8d8bef9SDimitry Andric W->OS << Str; 2930b57cec5SDimitry Andric } 2940b57cec5SDimitry Andric 2955ffd83dbSDimitry Andric void writeI32(int32_t val) { 2965ffd83dbSDimitry Andric char Buffer[4]; 2975ffd83dbSDimitry Andric support::endian::write32le(Buffer, val); 298e8d8bef9SDimitry Andric W->OS.write(Buffer, sizeof(Buffer)); 2995ffd83dbSDimitry Andric } 3005ffd83dbSDimitry Andric 3015ffd83dbSDimitry Andric void writeI64(int64_t val) { 3025ffd83dbSDimitry Andric char Buffer[8]; 3035ffd83dbSDimitry Andric support::endian::write64le(Buffer, val); 304e8d8bef9SDimitry Andric W->OS.write(Buffer, sizeof(Buffer)); 3055ffd83dbSDimitry Andric } 3065ffd83dbSDimitry Andric 307e8d8bef9SDimitry Andric void writeValueType(wasm::ValType Ty) { W->OS << static_cast<char>(Ty); } 3080b57cec5SDimitry Andric 309e8d8bef9SDimitry Andric void writeTypeSection(ArrayRef<wasm::WasmSignature> Signatures); 3105ffd83dbSDimitry Andric void writeImportSection(ArrayRef<wasm::WasmImport> Imports, uint64_t DataSize, 3110b57cec5SDimitry Andric uint32_t NumElements); 3120b57cec5SDimitry Andric void writeFunctionSection(ArrayRef<WasmFunction> Functions); 3130b57cec5SDimitry Andric void writeExportSection(ArrayRef<wasm::WasmExport> Exports); 3140b57cec5SDimitry Andric void writeElemSection(ArrayRef<uint32_t> TableElems); 3150b57cec5SDimitry Andric void writeDataCountSection(); 3165ffd83dbSDimitry Andric uint32_t writeCodeSection(const MCAssembler &Asm, const MCAsmLayout &Layout, 3170b57cec5SDimitry Andric ArrayRef<WasmFunction> Functions); 3185ffd83dbSDimitry Andric uint32_t writeDataSection(const MCAsmLayout &Layout); 3190b57cec5SDimitry Andric void writeEventSection(ArrayRef<wasm::WasmEventType> Events); 3205ffd83dbSDimitry Andric void writeGlobalSection(ArrayRef<wasm::WasmGlobal> Globals); 321e8d8bef9SDimitry Andric void writeTableSection(ArrayRef<wasm::WasmTable> Tables); 3220b57cec5SDimitry Andric void writeRelocSection(uint32_t SectionIndex, StringRef Name, 3230b57cec5SDimitry Andric std::vector<WasmRelocationEntry> &Relocations); 3240b57cec5SDimitry Andric void writeLinkingMetaDataSection( 3250b57cec5SDimitry Andric ArrayRef<wasm::WasmSymbolInfo> SymbolInfos, 3260b57cec5SDimitry Andric ArrayRef<std::pair<uint16_t, uint32_t>> InitFuncs, 3270b57cec5SDimitry Andric const std::map<StringRef, std::vector<WasmComdatEntry>> &Comdats); 3280b57cec5SDimitry Andric void writeCustomSection(WasmCustomSection &CustomSection, 3290b57cec5SDimitry Andric const MCAssembler &Asm, const MCAsmLayout &Layout); 3300b57cec5SDimitry Andric void writeCustomRelocSections(); 3310b57cec5SDimitry Andric 3325ffd83dbSDimitry Andric uint64_t getProvisionalValue(const WasmRelocationEntry &RelEntry, 3335ffd83dbSDimitry Andric const MCAsmLayout &Layout); 3340b57cec5SDimitry Andric void applyRelocations(ArrayRef<WasmRelocationEntry> Relocations, 3355ffd83dbSDimitry Andric uint64_t ContentsOffset, const MCAsmLayout &Layout); 3360b57cec5SDimitry Andric 3370b57cec5SDimitry Andric uint32_t getRelocationIndexValue(const WasmRelocationEntry &RelEntry); 3380b57cec5SDimitry Andric uint32_t getFunctionType(const MCSymbolWasm &Symbol); 3390b57cec5SDimitry Andric uint32_t getEventType(const MCSymbolWasm &Symbol); 3400b57cec5SDimitry Andric void registerFunctionType(const MCSymbolWasm &Symbol); 3410b57cec5SDimitry Andric void registerEventType(const MCSymbolWasm &Symbol); 3420b57cec5SDimitry Andric }; 3430b57cec5SDimitry Andric 3440b57cec5SDimitry Andric } // end anonymous namespace 3450b57cec5SDimitry Andric 3460b57cec5SDimitry Andric // Write out a section header and a patchable section size field. 3470b57cec5SDimitry Andric void WasmObjectWriter::startSection(SectionBookkeeping &Section, 3480b57cec5SDimitry Andric unsigned SectionId) { 3490b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "startSection " << SectionId << "\n"); 350e8d8bef9SDimitry Andric W->OS << char(SectionId); 3510b57cec5SDimitry Andric 352e8d8bef9SDimitry Andric Section.SizeOffset = W->OS.tell(); 3530b57cec5SDimitry Andric 3540b57cec5SDimitry Andric // The section size. We don't know the size yet, so reserve enough space 3550b57cec5SDimitry Andric // for any 32-bit value; we'll patch it later. 356e8d8bef9SDimitry Andric encodeULEB128(0, W->OS, 5); 3570b57cec5SDimitry Andric 3580b57cec5SDimitry Andric // The position where the section starts, for measuring its size. 359e8d8bef9SDimitry Andric Section.ContentsOffset = W->OS.tell(); 360e8d8bef9SDimitry Andric Section.PayloadOffset = W->OS.tell(); 3610b57cec5SDimitry Andric Section.Index = SectionCount++; 3620b57cec5SDimitry Andric } 3630b57cec5SDimitry Andric 3640b57cec5SDimitry Andric void WasmObjectWriter::startCustomSection(SectionBookkeeping &Section, 3650b57cec5SDimitry Andric StringRef Name) { 3660b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "startCustomSection " << Name << "\n"); 3670b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_CUSTOM); 3680b57cec5SDimitry Andric 3690b57cec5SDimitry Andric // The position where the section header ends, for measuring its size. 370e8d8bef9SDimitry Andric Section.PayloadOffset = W->OS.tell(); 3710b57cec5SDimitry Andric 3720b57cec5SDimitry Andric // Custom sections in wasm also have a string identifier. 3730b57cec5SDimitry Andric writeString(Name); 3740b57cec5SDimitry Andric 3750b57cec5SDimitry Andric // The position where the custom section starts. 376e8d8bef9SDimitry Andric Section.ContentsOffset = W->OS.tell(); 3770b57cec5SDimitry Andric } 3780b57cec5SDimitry Andric 3790b57cec5SDimitry Andric // Now that the section is complete and we know how big it is, patch up the 3800b57cec5SDimitry Andric // section size field at the start of the section. 3810b57cec5SDimitry Andric void WasmObjectWriter::endSection(SectionBookkeeping &Section) { 382e8d8bef9SDimitry Andric uint64_t Size = W->OS.tell(); 3830b57cec5SDimitry Andric // /dev/null doesn't support seek/tell and can report offset of 0. 3840b57cec5SDimitry Andric // Simply skip this patching in that case. 3850b57cec5SDimitry Andric if (!Size) 3860b57cec5SDimitry Andric return; 3870b57cec5SDimitry Andric 3880b57cec5SDimitry Andric Size -= Section.PayloadOffset; 3890b57cec5SDimitry Andric if (uint32_t(Size) != Size) 3900b57cec5SDimitry Andric report_fatal_error("section size does not fit in a uint32_t"); 3910b57cec5SDimitry Andric 3920b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "endSection size=" << Size << "\n"); 3930b57cec5SDimitry Andric 3940b57cec5SDimitry Andric // Write the final section size to the payload_len field, which follows 3950b57cec5SDimitry Andric // the section id byte. 396e8d8bef9SDimitry Andric writePatchableLEB<5>(static_cast<raw_pwrite_stream &>(W->OS), Size, 3970b57cec5SDimitry Andric Section.SizeOffset); 3980b57cec5SDimitry Andric } 3990b57cec5SDimitry Andric 4000b57cec5SDimitry Andric // Emit the Wasm header. 4010b57cec5SDimitry Andric void WasmObjectWriter::writeHeader(const MCAssembler &Asm) { 402e8d8bef9SDimitry Andric W->OS.write(wasm::WasmMagic, sizeof(wasm::WasmMagic)); 403e8d8bef9SDimitry Andric W->write<uint32_t>(wasm::WasmVersion); 4040b57cec5SDimitry Andric } 4050b57cec5SDimitry Andric 4060b57cec5SDimitry Andric void WasmObjectWriter::executePostLayoutBinding(MCAssembler &Asm, 4070b57cec5SDimitry Andric const MCAsmLayout &Layout) { 408e8d8bef9SDimitry Andric // As a stopgap measure until call_indirect instructions start explicitly 409e8d8bef9SDimitry Andric // referencing the indirect function table via TABLE_NUMBER relocs, ensure 410e8d8bef9SDimitry Andric // that the indirect function table import makes it to the output if anything 411e8d8bef9SDimitry Andric // in the compilation unit has caused it to be present. 412e8d8bef9SDimitry Andric if (auto *Sym = Asm.getContext().lookupSymbol("__indirect_function_table")) 413e8d8bef9SDimitry Andric Asm.registerSymbol(*Sym); 414e8d8bef9SDimitry Andric 4150b57cec5SDimitry Andric // Build a map of sections to the function that defines them, for use 4160b57cec5SDimitry Andric // in recordRelocation. 4170b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 4180b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 4190b57cec5SDimitry Andric if (WS.isDefined() && WS.isFunction() && !WS.isVariable()) { 4200b57cec5SDimitry Andric const auto &Sec = static_cast<const MCSectionWasm &>(S.getSection()); 4210b57cec5SDimitry Andric auto Pair = SectionFunctions.insert(std::make_pair(&Sec, &S)); 4220b57cec5SDimitry Andric if (!Pair.second) 4230b57cec5SDimitry Andric report_fatal_error("section already has a defining function: " + 4245ffd83dbSDimitry Andric Sec.getName()); 4250b57cec5SDimitry Andric } 4260b57cec5SDimitry Andric } 4270b57cec5SDimitry Andric } 4280b57cec5SDimitry Andric 4290b57cec5SDimitry Andric void WasmObjectWriter::recordRelocation(MCAssembler &Asm, 4300b57cec5SDimitry Andric const MCAsmLayout &Layout, 4310b57cec5SDimitry Andric const MCFragment *Fragment, 4320b57cec5SDimitry Andric const MCFixup &Fixup, MCValue Target, 4330b57cec5SDimitry Andric uint64_t &FixedValue) { 4348bcb0991SDimitry Andric // The WebAssembly backend should never generate FKF_IsPCRel fixups 4358bcb0991SDimitry Andric assert(!(Asm.getBackend().getFixupKindInfo(Fixup.getKind()).Flags & 4368bcb0991SDimitry Andric MCFixupKindInfo::FKF_IsPCRel)); 4378bcb0991SDimitry Andric 4380b57cec5SDimitry Andric const auto &FixupSection = cast<MCSectionWasm>(*Fragment->getParent()); 4390b57cec5SDimitry Andric uint64_t C = Target.getConstant(); 4400b57cec5SDimitry Andric uint64_t FixupOffset = Layout.getFragmentOffset(Fragment) + Fixup.getOffset(); 4410b57cec5SDimitry Andric MCContext &Ctx = Asm.getContext(); 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 4595ffd83dbSDimitry Andric // The .init_array isn't translated as data, so don't do relocations in it. 4605ffd83dbSDimitry Andric if (FixupSection.getName().startswith(".init_array")) { 4615ffd83dbSDimitry Andric SymA->setUsedInInitArray(); 4625ffd83dbSDimitry Andric return; 4635ffd83dbSDimitry Andric } 4645ffd83dbSDimitry Andric 4658bcb0991SDimitry Andric if (SymA->isVariable()) { 4660b57cec5SDimitry Andric const MCExpr *Expr = SymA->getVariableValue(); 4675ffd83dbSDimitry Andric if (const auto *Inner = dyn_cast<MCSymbolRefExpr>(Expr)) 4680b57cec5SDimitry Andric if (Inner->getKind() == MCSymbolRefExpr::VK_WEAKREF) 4690b57cec5SDimitry Andric llvm_unreachable("weakref used in reloc not yet implemented"); 4700b57cec5SDimitry Andric } 4710b57cec5SDimitry Andric 4720b57cec5SDimitry Andric // Put any constant offset in an addend. Offsets can be negative, and 4730b57cec5SDimitry Andric // LLVM expects wrapping, in contrast to wasm's immediates which can't 4740b57cec5SDimitry Andric // be negative and don't wrap. 4750b57cec5SDimitry Andric FixedValue = 0; 4760b57cec5SDimitry Andric 4770b57cec5SDimitry Andric unsigned Type = TargetObjectWriter->getRelocType(Target, Fixup); 4780b57cec5SDimitry Andric 4790b57cec5SDimitry Andric // Absolute offset within a section or a function. 4800b57cec5SDimitry Andric // Currently only supported for for metadata sections. 4810b57cec5SDimitry Andric // See: test/MC/WebAssembly/blockaddress.ll 4820b57cec5SDimitry Andric if (Type == wasm::R_WASM_FUNCTION_OFFSET_I32 || 483e8d8bef9SDimitry Andric Type == wasm::R_WASM_FUNCTION_OFFSET_I64 || 4840b57cec5SDimitry Andric Type == wasm::R_WASM_SECTION_OFFSET_I32) { 4850b57cec5SDimitry Andric if (!FixupSection.getKind().isMetadata()) 4860b57cec5SDimitry Andric report_fatal_error("relocations for function or section offsets are " 4870b57cec5SDimitry Andric "only supported in metadata sections"); 4880b57cec5SDimitry Andric 4890b57cec5SDimitry Andric const MCSymbol *SectionSymbol = nullptr; 4900b57cec5SDimitry Andric const MCSection &SecA = SymA->getSection(); 4910b57cec5SDimitry Andric if (SecA.getKind().isText()) 4920b57cec5SDimitry Andric SectionSymbol = SectionFunctions.find(&SecA)->second; 4930b57cec5SDimitry Andric else 4940b57cec5SDimitry Andric SectionSymbol = SecA.getBeginSymbol(); 4950b57cec5SDimitry Andric if (!SectionSymbol) 4960b57cec5SDimitry Andric report_fatal_error("section symbol is required for relocation"); 4970b57cec5SDimitry Andric 4980b57cec5SDimitry Andric C += Layout.getSymbolOffset(*SymA); 4990b57cec5SDimitry Andric SymA = cast<MCSymbolWasm>(SectionSymbol); 5000b57cec5SDimitry Andric } 5010b57cec5SDimitry Andric 502e8d8bef9SDimitry Andric if (Type == wasm::R_WASM_TABLE_INDEX_REL_SLEB || 503e8d8bef9SDimitry Andric Type == wasm::R_WASM_TABLE_INDEX_SLEB || 504e8d8bef9SDimitry Andric Type == wasm::R_WASM_TABLE_INDEX_SLEB64 || 505e8d8bef9SDimitry Andric Type == wasm::R_WASM_TABLE_INDEX_I32 || 506e8d8bef9SDimitry Andric Type == wasm::R_WASM_TABLE_INDEX_I64) { 507e8d8bef9SDimitry Andric // TABLE_INDEX relocs implicitly use the default indirect function table. 508e8d8bef9SDimitry Andric auto TableName = "__indirect_function_table"; 509e8d8bef9SDimitry Andric MCSymbolWasm *Sym = cast_or_null<MCSymbolWasm>(Ctx.lookupSymbol(TableName)); 510e8d8bef9SDimitry Andric if (Sym) { 511e8d8bef9SDimitry Andric if (!Sym->isFunctionTable()) 512e8d8bef9SDimitry Andric Ctx.reportError( 513e8d8bef9SDimitry Andric Fixup.getLoc(), 514e8d8bef9SDimitry Andric "symbol '__indirect_function_table' is not a function table"); 515e8d8bef9SDimitry Andric } else { 516e8d8bef9SDimitry Andric Sym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(TableName)); 517e8d8bef9SDimitry Andric Sym->setFunctionTable(); 518e8d8bef9SDimitry Andric // The default function table is synthesized by the linker. 519e8d8bef9SDimitry Andric Sym->setUndefined(); 520e8d8bef9SDimitry Andric } 521e8d8bef9SDimitry Andric Sym->setUsedInReloc(); 522e8d8bef9SDimitry Andric Asm.registerSymbol(*Sym); 523e8d8bef9SDimitry Andric } 524e8d8bef9SDimitry Andric 5250b57cec5SDimitry Andric // Relocation other than R_WASM_TYPE_INDEX_LEB are required to be 5260b57cec5SDimitry Andric // against a named symbol. 5270b57cec5SDimitry Andric if (Type != wasm::R_WASM_TYPE_INDEX_LEB) { 5280b57cec5SDimitry Andric if (SymA->getName().empty()) 5290b57cec5SDimitry Andric report_fatal_error("relocations against un-named temporaries are not yet " 5300b57cec5SDimitry Andric "supported by wasm"); 5310b57cec5SDimitry Andric 5320b57cec5SDimitry Andric SymA->setUsedInReloc(); 5330b57cec5SDimitry Andric } 5340b57cec5SDimitry Andric 5350b57cec5SDimitry Andric if (RefA->getKind() == MCSymbolRefExpr::VK_GOT) 5360b57cec5SDimitry Andric SymA->setUsedInGOT(); 5370b57cec5SDimitry Andric 5380b57cec5SDimitry Andric WasmRelocationEntry Rec(FixupOffset, SymA, C, Type, &FixupSection); 5390b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "WasmReloc: " << Rec << "\n"); 5400b57cec5SDimitry Andric 5410b57cec5SDimitry Andric if (FixupSection.isWasmData()) { 5420b57cec5SDimitry Andric DataRelocations.push_back(Rec); 5430b57cec5SDimitry Andric } else if (FixupSection.getKind().isText()) { 5440b57cec5SDimitry Andric CodeRelocations.push_back(Rec); 5450b57cec5SDimitry Andric } else if (FixupSection.getKind().isMetadata()) { 5460b57cec5SDimitry Andric CustomSectionsRelocations[&FixupSection].push_back(Rec); 5470b57cec5SDimitry Andric } else { 5480b57cec5SDimitry Andric llvm_unreachable("unexpected section type"); 5490b57cec5SDimitry Andric } 5500b57cec5SDimitry Andric } 5510b57cec5SDimitry Andric 5520b57cec5SDimitry Andric // Compute a value to write into the code at the location covered 5530b57cec5SDimitry Andric // by RelEntry. This value isn't used by the static linker; it just serves 5540b57cec5SDimitry Andric // to make the object format more readable and more likely to be directly 5550b57cec5SDimitry Andric // useable. 5565ffd83dbSDimitry Andric uint64_t 5575ffd83dbSDimitry Andric WasmObjectWriter::getProvisionalValue(const WasmRelocationEntry &RelEntry, 5585ffd83dbSDimitry Andric const MCAsmLayout &Layout) { 5595ffd83dbSDimitry Andric if ((RelEntry.Type == wasm::R_WASM_GLOBAL_INDEX_LEB || 5605ffd83dbSDimitry Andric RelEntry.Type == wasm::R_WASM_GLOBAL_INDEX_I32) && 5615ffd83dbSDimitry Andric !RelEntry.Symbol->isGlobal()) { 5620b57cec5SDimitry Andric assert(GOTIndices.count(RelEntry.Symbol) > 0 && "symbol not found in GOT index space"); 5630b57cec5SDimitry Andric return GOTIndices[RelEntry.Symbol]; 5640b57cec5SDimitry Andric } 5650b57cec5SDimitry Andric 5660b57cec5SDimitry Andric switch (RelEntry.Type) { 5670b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_REL_SLEB: 5680b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_SLEB: 569e8d8bef9SDimitry Andric case wasm::R_WASM_TABLE_INDEX_SLEB64: 570e8d8bef9SDimitry Andric case wasm::R_WASM_TABLE_INDEX_I32: 571e8d8bef9SDimitry Andric case wasm::R_WASM_TABLE_INDEX_I64: { 5720b57cec5SDimitry Andric // Provisional value is table address of the resolved symbol itself 5735ffd83dbSDimitry Andric const MCSymbolWasm *Base = 5745ffd83dbSDimitry Andric cast<MCSymbolWasm>(Layout.getBaseSymbol(*RelEntry.Symbol)); 5755ffd83dbSDimitry Andric assert(Base->isFunction()); 5765ffd83dbSDimitry Andric if (RelEntry.Type == wasm::R_WASM_TABLE_INDEX_REL_SLEB) 5775ffd83dbSDimitry Andric return TableIndices[Base] - InitialTableOffset; 5785ffd83dbSDimitry Andric else 5795ffd83dbSDimitry Andric return TableIndices[Base]; 5800b57cec5SDimitry Andric } 5810b57cec5SDimitry Andric case wasm::R_WASM_TYPE_INDEX_LEB: 5820b57cec5SDimitry Andric // Provisional value is same as the index 5830b57cec5SDimitry Andric return getRelocationIndexValue(RelEntry); 5840b57cec5SDimitry Andric case wasm::R_WASM_FUNCTION_INDEX_LEB: 5850b57cec5SDimitry Andric case wasm::R_WASM_GLOBAL_INDEX_LEB: 5865ffd83dbSDimitry Andric case wasm::R_WASM_GLOBAL_INDEX_I32: 5870b57cec5SDimitry Andric case wasm::R_WASM_EVENT_INDEX_LEB: 588e8d8bef9SDimitry Andric case wasm::R_WASM_TABLE_NUMBER_LEB: 5890b57cec5SDimitry Andric // Provisional value is function/global/event Wasm index 5900b57cec5SDimitry Andric assert(WasmIndices.count(RelEntry.Symbol) > 0 && "symbol not found in wasm index space"); 5910b57cec5SDimitry Andric return WasmIndices[RelEntry.Symbol]; 5920b57cec5SDimitry Andric case wasm::R_WASM_FUNCTION_OFFSET_I32: 593e8d8bef9SDimitry Andric case wasm::R_WASM_FUNCTION_OFFSET_I64: 5940b57cec5SDimitry Andric case wasm::R_WASM_SECTION_OFFSET_I32: { 5950b57cec5SDimitry Andric const auto &Section = 5960b57cec5SDimitry Andric static_cast<const MCSectionWasm &>(RelEntry.Symbol->getSection()); 5970b57cec5SDimitry Andric return Section.getSectionOffset() + RelEntry.Addend; 5980b57cec5SDimitry Andric } 5990b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_LEB: 6005ffd83dbSDimitry Andric case wasm::R_WASM_MEMORY_ADDR_LEB64: 6015ffd83dbSDimitry Andric case wasm::R_WASM_MEMORY_ADDR_SLEB: 6025ffd83dbSDimitry Andric case wasm::R_WASM_MEMORY_ADDR_SLEB64: 6030b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_REL_SLEB: 6045ffd83dbSDimitry Andric case wasm::R_WASM_MEMORY_ADDR_REL_SLEB64: 6055ffd83dbSDimitry Andric case wasm::R_WASM_MEMORY_ADDR_I32: 606e8d8bef9SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_I64: 607e8d8bef9SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_TLS_SLEB: { 608e8d8bef9SDimitry Andric // Provisional value is address of the global plus the offset 6095ffd83dbSDimitry Andric const MCSymbolWasm *Base = 6105ffd83dbSDimitry Andric cast<MCSymbolWasm>(Layout.getBaseSymbol(*RelEntry.Symbol)); 6110b57cec5SDimitry Andric // For undefined symbols, use zero 6125ffd83dbSDimitry Andric if (!Base->isDefined()) 6130b57cec5SDimitry Andric return 0; 614e8d8bef9SDimitry Andric const wasm::WasmDataReference &BaseRef = DataLocations[Base], 615e8d8bef9SDimitry Andric &SymRef = DataLocations[RelEntry.Symbol]; 616e8d8bef9SDimitry Andric const WasmDataSegment &Segment = DataSegments[BaseRef.Segment]; 6170b57cec5SDimitry Andric // Ignore overflow. LLVM allows address arithmetic to silently wrap. 618e8d8bef9SDimitry Andric return Segment.Offset + BaseRef.Offset + SymRef.Offset + RelEntry.Addend; 6190b57cec5SDimitry Andric } 6200b57cec5SDimitry Andric default: 6210b57cec5SDimitry Andric llvm_unreachable("invalid relocation type"); 6220b57cec5SDimitry Andric } 6230b57cec5SDimitry Andric } 6240b57cec5SDimitry Andric 6250b57cec5SDimitry Andric static void addData(SmallVectorImpl<char> &DataBytes, 6260b57cec5SDimitry Andric MCSectionWasm &DataSection) { 6275ffd83dbSDimitry Andric LLVM_DEBUG(errs() << "addData: " << DataSection.getName() << "\n"); 6280b57cec5SDimitry Andric 6290b57cec5SDimitry Andric DataBytes.resize(alignTo(DataBytes.size(), DataSection.getAlignment())); 6300b57cec5SDimitry Andric 6310b57cec5SDimitry Andric for (const MCFragment &Frag : DataSection) { 6320b57cec5SDimitry Andric if (Frag.hasInstructions()) 6330b57cec5SDimitry Andric report_fatal_error("only data supported in data sections"); 6340b57cec5SDimitry Andric 6350b57cec5SDimitry Andric if (auto *Align = dyn_cast<MCAlignFragment>(&Frag)) { 6360b57cec5SDimitry Andric if (Align->getValueSize() != 1) 6370b57cec5SDimitry Andric report_fatal_error("only byte values supported for alignment"); 6380b57cec5SDimitry Andric // If nops are requested, use zeros, as this is the data section. 6390b57cec5SDimitry Andric uint8_t Value = Align->hasEmitNops() ? 0 : Align->getValue(); 6400b57cec5SDimitry Andric uint64_t Size = 6410b57cec5SDimitry Andric std::min<uint64_t>(alignTo(DataBytes.size(), Align->getAlignment()), 6420b57cec5SDimitry Andric DataBytes.size() + Align->getMaxBytesToEmit()); 6430b57cec5SDimitry Andric DataBytes.resize(Size, Value); 6440b57cec5SDimitry Andric } else if (auto *Fill = dyn_cast<MCFillFragment>(&Frag)) { 6450b57cec5SDimitry Andric int64_t NumValues; 6460b57cec5SDimitry Andric if (!Fill->getNumValues().evaluateAsAbsolute(NumValues)) 6470b57cec5SDimitry Andric llvm_unreachable("The fill should be an assembler constant"); 6480b57cec5SDimitry Andric DataBytes.insert(DataBytes.end(), Fill->getValueSize() * NumValues, 6490b57cec5SDimitry Andric Fill->getValue()); 6500b57cec5SDimitry Andric } else if (auto *LEB = dyn_cast<MCLEBFragment>(&Frag)) { 6510b57cec5SDimitry Andric const SmallVectorImpl<char> &Contents = LEB->getContents(); 652e8d8bef9SDimitry Andric llvm::append_range(DataBytes, Contents); 6530b57cec5SDimitry Andric } else { 6540b57cec5SDimitry Andric const auto &DataFrag = cast<MCDataFragment>(Frag); 6550b57cec5SDimitry Andric const SmallVectorImpl<char> &Contents = DataFrag.getContents(); 656e8d8bef9SDimitry Andric llvm::append_range(DataBytes, Contents); 6570b57cec5SDimitry Andric } 6580b57cec5SDimitry Andric } 6590b57cec5SDimitry Andric 6600b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "addData -> " << DataBytes.size() << "\n"); 6610b57cec5SDimitry Andric } 6620b57cec5SDimitry Andric 6630b57cec5SDimitry Andric uint32_t 6640b57cec5SDimitry Andric WasmObjectWriter::getRelocationIndexValue(const WasmRelocationEntry &RelEntry) { 6650b57cec5SDimitry Andric if (RelEntry.Type == wasm::R_WASM_TYPE_INDEX_LEB) { 6660b57cec5SDimitry Andric if (!TypeIndices.count(RelEntry.Symbol)) 6670b57cec5SDimitry Andric report_fatal_error("symbol not found in type index space: " + 6680b57cec5SDimitry Andric RelEntry.Symbol->getName()); 6690b57cec5SDimitry Andric return TypeIndices[RelEntry.Symbol]; 6700b57cec5SDimitry Andric } 6710b57cec5SDimitry Andric 6720b57cec5SDimitry Andric return RelEntry.Symbol->getIndex(); 6730b57cec5SDimitry Andric } 6740b57cec5SDimitry Andric 6750b57cec5SDimitry Andric // Apply the portions of the relocation records that we can handle ourselves 6760b57cec5SDimitry Andric // directly. 6770b57cec5SDimitry Andric void WasmObjectWriter::applyRelocations( 6785ffd83dbSDimitry Andric ArrayRef<WasmRelocationEntry> Relocations, uint64_t ContentsOffset, 6795ffd83dbSDimitry Andric const MCAsmLayout &Layout) { 680e8d8bef9SDimitry Andric auto &Stream = static_cast<raw_pwrite_stream &>(W->OS); 6810b57cec5SDimitry Andric for (const WasmRelocationEntry &RelEntry : Relocations) { 6820b57cec5SDimitry Andric uint64_t Offset = ContentsOffset + 6830b57cec5SDimitry Andric RelEntry.FixupSection->getSectionOffset() + 6840b57cec5SDimitry Andric RelEntry.Offset; 6850b57cec5SDimitry Andric 6860b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "applyRelocation: " << RelEntry << "\n"); 6875ffd83dbSDimitry Andric auto Value = getProvisionalValue(RelEntry, Layout); 6880b57cec5SDimitry Andric 6890b57cec5SDimitry Andric switch (RelEntry.Type) { 6900b57cec5SDimitry Andric case wasm::R_WASM_FUNCTION_INDEX_LEB: 6910b57cec5SDimitry Andric case wasm::R_WASM_TYPE_INDEX_LEB: 6920b57cec5SDimitry Andric case wasm::R_WASM_GLOBAL_INDEX_LEB: 6930b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_LEB: 6940b57cec5SDimitry Andric case wasm::R_WASM_EVENT_INDEX_LEB: 695e8d8bef9SDimitry Andric case wasm::R_WASM_TABLE_NUMBER_LEB: 6965ffd83dbSDimitry Andric writePatchableLEB<5>(Stream, Value, Offset); 6975ffd83dbSDimitry Andric break; 6985ffd83dbSDimitry Andric case wasm::R_WASM_MEMORY_ADDR_LEB64: 6995ffd83dbSDimitry Andric writePatchableLEB<10>(Stream, Value, Offset); 7000b57cec5SDimitry Andric break; 7010b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_I32: 7020b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_I32: 7030b57cec5SDimitry Andric case wasm::R_WASM_FUNCTION_OFFSET_I32: 7040b57cec5SDimitry Andric case wasm::R_WASM_SECTION_OFFSET_I32: 7055ffd83dbSDimitry Andric case wasm::R_WASM_GLOBAL_INDEX_I32: 7065ffd83dbSDimitry Andric patchI32(Stream, Value, Offset); 7075ffd83dbSDimitry Andric break; 708e8d8bef9SDimitry Andric case wasm::R_WASM_TABLE_INDEX_I64: 7095ffd83dbSDimitry Andric case wasm::R_WASM_MEMORY_ADDR_I64: 710e8d8bef9SDimitry Andric case wasm::R_WASM_FUNCTION_OFFSET_I64: 7115ffd83dbSDimitry Andric patchI64(Stream, Value, Offset); 7120b57cec5SDimitry Andric break; 7130b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_SLEB: 7140b57cec5SDimitry Andric case wasm::R_WASM_TABLE_INDEX_REL_SLEB: 7150b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_SLEB: 7160b57cec5SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_REL_SLEB: 717e8d8bef9SDimitry Andric case wasm::R_WASM_MEMORY_ADDR_TLS_SLEB: 7185ffd83dbSDimitry Andric writePatchableSLEB<5>(Stream, Value, Offset); 7195ffd83dbSDimitry Andric break; 720e8d8bef9SDimitry Andric case wasm::R_WASM_TABLE_INDEX_SLEB64: 7215ffd83dbSDimitry Andric case wasm::R_WASM_MEMORY_ADDR_SLEB64: 7225ffd83dbSDimitry Andric case wasm::R_WASM_MEMORY_ADDR_REL_SLEB64: 7235ffd83dbSDimitry Andric writePatchableSLEB<10>(Stream, Value, Offset); 7240b57cec5SDimitry Andric break; 7250b57cec5SDimitry Andric default: 7260b57cec5SDimitry Andric llvm_unreachable("invalid relocation type"); 7270b57cec5SDimitry Andric } 7280b57cec5SDimitry Andric } 7290b57cec5SDimitry Andric } 7300b57cec5SDimitry Andric 731e8d8bef9SDimitry Andric void WasmObjectWriter::writeTypeSection( 732e8d8bef9SDimitry Andric ArrayRef<wasm::WasmSignature> Signatures) { 7330b57cec5SDimitry Andric if (Signatures.empty()) 7340b57cec5SDimitry Andric return; 7350b57cec5SDimitry Andric 7360b57cec5SDimitry Andric SectionBookkeeping Section; 7370b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_TYPE); 7380b57cec5SDimitry Andric 739e8d8bef9SDimitry Andric encodeULEB128(Signatures.size(), W->OS); 7400b57cec5SDimitry Andric 741e8d8bef9SDimitry Andric for (const wasm::WasmSignature &Sig : Signatures) { 742e8d8bef9SDimitry Andric W->OS << char(wasm::WASM_TYPE_FUNC); 743e8d8bef9SDimitry Andric encodeULEB128(Sig.Params.size(), W->OS); 7440b57cec5SDimitry Andric for (wasm::ValType Ty : Sig.Params) 7450b57cec5SDimitry Andric writeValueType(Ty); 746e8d8bef9SDimitry Andric encodeULEB128(Sig.Returns.size(), W->OS); 7470b57cec5SDimitry Andric for (wasm::ValType Ty : Sig.Returns) 7480b57cec5SDimitry Andric writeValueType(Ty); 7490b57cec5SDimitry Andric } 7500b57cec5SDimitry Andric 7510b57cec5SDimitry Andric endSection(Section); 7520b57cec5SDimitry Andric } 7530b57cec5SDimitry Andric 7540b57cec5SDimitry Andric void WasmObjectWriter::writeImportSection(ArrayRef<wasm::WasmImport> Imports, 7555ffd83dbSDimitry Andric uint64_t DataSize, 7560b57cec5SDimitry Andric uint32_t NumElements) { 7570b57cec5SDimitry Andric if (Imports.empty()) 7580b57cec5SDimitry Andric return; 7590b57cec5SDimitry Andric 7605ffd83dbSDimitry Andric uint64_t NumPages = (DataSize + wasm::WasmPageSize - 1) / wasm::WasmPageSize; 7610b57cec5SDimitry Andric 7620b57cec5SDimitry Andric SectionBookkeeping Section; 7630b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_IMPORT); 7640b57cec5SDimitry Andric 765e8d8bef9SDimitry Andric encodeULEB128(Imports.size(), W->OS); 7660b57cec5SDimitry Andric for (const wasm::WasmImport &Import : Imports) { 7670b57cec5SDimitry Andric writeString(Import.Module); 7680b57cec5SDimitry Andric writeString(Import.Field); 769e8d8bef9SDimitry Andric W->OS << char(Import.Kind); 7700b57cec5SDimitry Andric 7710b57cec5SDimitry Andric switch (Import.Kind) { 7720b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_FUNCTION: 773e8d8bef9SDimitry Andric encodeULEB128(Import.SigIndex, W->OS); 7740b57cec5SDimitry Andric break; 7750b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_GLOBAL: 776e8d8bef9SDimitry Andric W->OS << char(Import.Global.Type); 777e8d8bef9SDimitry Andric W->OS << char(Import.Global.Mutable ? 1 : 0); 7780b57cec5SDimitry Andric break; 7790b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_MEMORY: 780e8d8bef9SDimitry Andric encodeULEB128(Import.Memory.Flags, W->OS); 781e8d8bef9SDimitry Andric encodeULEB128(NumPages, W->OS); // initial 7820b57cec5SDimitry Andric break; 7830b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_TABLE: 784e8d8bef9SDimitry Andric W->OS << char(Import.Table.ElemType); 785e8d8bef9SDimitry Andric encodeULEB128(0, W->OS); // flags 786e8d8bef9SDimitry Andric encodeULEB128(NumElements, W->OS); // initial 7870b57cec5SDimitry Andric break; 7880b57cec5SDimitry Andric case wasm::WASM_EXTERNAL_EVENT: 789e8d8bef9SDimitry Andric encodeULEB128(Import.Event.Attribute, W->OS); 790e8d8bef9SDimitry Andric encodeULEB128(Import.Event.SigIndex, W->OS); 7910b57cec5SDimitry Andric break; 7920b57cec5SDimitry Andric default: 7930b57cec5SDimitry Andric llvm_unreachable("unsupported import kind"); 7940b57cec5SDimitry Andric } 7950b57cec5SDimitry Andric } 7960b57cec5SDimitry Andric 7970b57cec5SDimitry Andric endSection(Section); 7980b57cec5SDimitry Andric } 7990b57cec5SDimitry Andric 8000b57cec5SDimitry Andric void WasmObjectWriter::writeFunctionSection(ArrayRef<WasmFunction> Functions) { 8010b57cec5SDimitry Andric if (Functions.empty()) 8020b57cec5SDimitry Andric return; 8030b57cec5SDimitry Andric 8040b57cec5SDimitry Andric SectionBookkeeping Section; 8050b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_FUNCTION); 8060b57cec5SDimitry Andric 807e8d8bef9SDimitry Andric encodeULEB128(Functions.size(), W->OS); 8080b57cec5SDimitry Andric for (const WasmFunction &Func : Functions) 809e8d8bef9SDimitry Andric encodeULEB128(Func.SigIndex, W->OS); 8100b57cec5SDimitry Andric 8110b57cec5SDimitry Andric endSection(Section); 8120b57cec5SDimitry Andric } 8130b57cec5SDimitry Andric 8140b57cec5SDimitry Andric void WasmObjectWriter::writeEventSection(ArrayRef<wasm::WasmEventType> Events) { 8150b57cec5SDimitry Andric if (Events.empty()) 8160b57cec5SDimitry Andric return; 8170b57cec5SDimitry Andric 8180b57cec5SDimitry Andric SectionBookkeeping Section; 8190b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_EVENT); 8200b57cec5SDimitry Andric 821e8d8bef9SDimitry Andric encodeULEB128(Events.size(), W->OS); 8220b57cec5SDimitry Andric for (const wasm::WasmEventType &Event : Events) { 823e8d8bef9SDimitry Andric encodeULEB128(Event.Attribute, W->OS); 824e8d8bef9SDimitry Andric encodeULEB128(Event.SigIndex, W->OS); 8250b57cec5SDimitry Andric } 8260b57cec5SDimitry Andric 8270b57cec5SDimitry Andric endSection(Section); 8280b57cec5SDimitry Andric } 8290b57cec5SDimitry Andric 8305ffd83dbSDimitry Andric void WasmObjectWriter::writeGlobalSection(ArrayRef<wasm::WasmGlobal> Globals) { 8315ffd83dbSDimitry Andric if (Globals.empty()) 8325ffd83dbSDimitry Andric return; 8335ffd83dbSDimitry Andric 8345ffd83dbSDimitry Andric SectionBookkeeping Section; 8355ffd83dbSDimitry Andric startSection(Section, wasm::WASM_SEC_GLOBAL); 8365ffd83dbSDimitry Andric 837e8d8bef9SDimitry Andric encodeULEB128(Globals.size(), W->OS); 8385ffd83dbSDimitry Andric for (const wasm::WasmGlobal &Global : Globals) { 839e8d8bef9SDimitry Andric encodeULEB128(Global.Type.Type, W->OS); 840e8d8bef9SDimitry Andric W->OS << char(Global.Type.Mutable); 841e8d8bef9SDimitry Andric W->OS << char(Global.InitExpr.Opcode); 8425ffd83dbSDimitry Andric switch (Global.Type.Type) { 8435ffd83dbSDimitry Andric case wasm::WASM_TYPE_I32: 844e8d8bef9SDimitry Andric encodeSLEB128(0, W->OS); 8455ffd83dbSDimitry Andric break; 8465ffd83dbSDimitry Andric case wasm::WASM_TYPE_I64: 847e8d8bef9SDimitry Andric encodeSLEB128(0, W->OS); 8485ffd83dbSDimitry Andric break; 8495ffd83dbSDimitry Andric case wasm::WASM_TYPE_F32: 8505ffd83dbSDimitry Andric writeI32(0); 8515ffd83dbSDimitry Andric break; 8525ffd83dbSDimitry Andric case wasm::WASM_TYPE_F64: 8535ffd83dbSDimitry Andric writeI64(0); 8545ffd83dbSDimitry Andric break; 8555ffd83dbSDimitry Andric case wasm::WASM_TYPE_EXTERNREF: 8565ffd83dbSDimitry Andric writeValueType(wasm::ValType::EXTERNREF); 8575ffd83dbSDimitry Andric break; 8585ffd83dbSDimitry Andric default: 8595ffd83dbSDimitry Andric llvm_unreachable("unexpected type"); 8605ffd83dbSDimitry Andric } 861e8d8bef9SDimitry Andric W->OS << char(wasm::WASM_OPCODE_END); 8625ffd83dbSDimitry Andric } 8635ffd83dbSDimitry Andric 8645ffd83dbSDimitry Andric endSection(Section); 8655ffd83dbSDimitry Andric } 8665ffd83dbSDimitry Andric 867e8d8bef9SDimitry Andric void WasmObjectWriter::writeTableSection(ArrayRef<wasm::WasmTable> Tables) { 868e8d8bef9SDimitry Andric if (Tables.empty()) 869e8d8bef9SDimitry Andric return; 870e8d8bef9SDimitry Andric 871e8d8bef9SDimitry Andric SectionBookkeeping Section; 872e8d8bef9SDimitry Andric startSection(Section, wasm::WASM_SEC_TABLE); 873e8d8bef9SDimitry Andric 874e8d8bef9SDimitry Andric encodeULEB128(Tables.size(), W->OS); 875e8d8bef9SDimitry Andric for (const wasm::WasmTable &Table : Tables) { 876e8d8bef9SDimitry Andric encodeULEB128(Table.Type.ElemType, W->OS); 877e8d8bef9SDimitry Andric encodeULEB128(Table.Type.Limits.Flags, W->OS); 878e8d8bef9SDimitry Andric encodeULEB128(Table.Type.Limits.Initial, W->OS); 879e8d8bef9SDimitry Andric if (Table.Type.Limits.Flags & wasm::WASM_LIMITS_FLAG_HAS_MAX) 880e8d8bef9SDimitry Andric encodeULEB128(Table.Type.Limits.Maximum, W->OS); 881e8d8bef9SDimitry Andric } 882e8d8bef9SDimitry Andric endSection(Section); 883e8d8bef9SDimitry Andric } 884e8d8bef9SDimitry Andric 8850b57cec5SDimitry Andric void WasmObjectWriter::writeExportSection(ArrayRef<wasm::WasmExport> Exports) { 8860b57cec5SDimitry Andric if (Exports.empty()) 8870b57cec5SDimitry Andric return; 8880b57cec5SDimitry Andric 8890b57cec5SDimitry Andric SectionBookkeeping Section; 8900b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_EXPORT); 8910b57cec5SDimitry Andric 892e8d8bef9SDimitry Andric encodeULEB128(Exports.size(), W->OS); 8930b57cec5SDimitry Andric for (const wasm::WasmExport &Export : Exports) { 8940b57cec5SDimitry Andric writeString(Export.Name); 895e8d8bef9SDimitry Andric W->OS << char(Export.Kind); 896e8d8bef9SDimitry Andric encodeULEB128(Export.Index, W->OS); 8970b57cec5SDimitry Andric } 8980b57cec5SDimitry Andric 8990b57cec5SDimitry Andric endSection(Section); 9000b57cec5SDimitry Andric } 9010b57cec5SDimitry Andric 9020b57cec5SDimitry Andric void WasmObjectWriter::writeElemSection(ArrayRef<uint32_t> TableElems) { 9030b57cec5SDimitry Andric if (TableElems.empty()) 9040b57cec5SDimitry Andric return; 9050b57cec5SDimitry Andric 9060b57cec5SDimitry Andric SectionBookkeeping Section; 9070b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_ELEM); 9080b57cec5SDimitry Andric 909e8d8bef9SDimitry Andric encodeULEB128(1, W->OS); // number of "segments" 910e8d8bef9SDimitry Andric encodeULEB128(0, W->OS); // the table index 9110b57cec5SDimitry Andric 9120b57cec5SDimitry Andric // init expr for starting offset 913e8d8bef9SDimitry Andric W->OS << char(wasm::WASM_OPCODE_I32_CONST); 914e8d8bef9SDimitry Andric encodeSLEB128(InitialTableOffset, W->OS); 915e8d8bef9SDimitry Andric W->OS << char(wasm::WASM_OPCODE_END); 9160b57cec5SDimitry Andric 917e8d8bef9SDimitry Andric encodeULEB128(TableElems.size(), W->OS); 9180b57cec5SDimitry Andric for (uint32_t Elem : TableElems) 919e8d8bef9SDimitry Andric encodeULEB128(Elem, W->OS); 9200b57cec5SDimitry Andric 9210b57cec5SDimitry Andric endSection(Section); 9220b57cec5SDimitry Andric } 9230b57cec5SDimitry Andric 9240b57cec5SDimitry Andric void WasmObjectWriter::writeDataCountSection() { 9250b57cec5SDimitry Andric if (DataSegments.empty()) 9260b57cec5SDimitry Andric return; 9270b57cec5SDimitry Andric 9280b57cec5SDimitry Andric SectionBookkeeping Section; 9290b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_DATACOUNT); 930e8d8bef9SDimitry Andric encodeULEB128(DataSegments.size(), W->OS); 9310b57cec5SDimitry Andric endSection(Section); 9320b57cec5SDimitry Andric } 9330b57cec5SDimitry Andric 9345ffd83dbSDimitry Andric uint32_t WasmObjectWriter::writeCodeSection(const MCAssembler &Asm, 9350b57cec5SDimitry Andric const MCAsmLayout &Layout, 9360b57cec5SDimitry Andric ArrayRef<WasmFunction> Functions) { 9370b57cec5SDimitry Andric if (Functions.empty()) 9385ffd83dbSDimitry Andric return 0; 9390b57cec5SDimitry Andric 9400b57cec5SDimitry Andric SectionBookkeeping Section; 9410b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_CODE); 9420b57cec5SDimitry Andric 943e8d8bef9SDimitry Andric encodeULEB128(Functions.size(), W->OS); 9440b57cec5SDimitry Andric 9450b57cec5SDimitry Andric for (const WasmFunction &Func : Functions) { 9460b57cec5SDimitry Andric auto &FuncSection = static_cast<MCSectionWasm &>(Func.Sym->getSection()); 9470b57cec5SDimitry Andric 9480b57cec5SDimitry Andric int64_t Size = 0; 9490b57cec5SDimitry Andric if (!Func.Sym->getSize()->evaluateAsAbsolute(Size, Layout)) 9500b57cec5SDimitry Andric report_fatal_error(".size expression must be evaluatable"); 9510b57cec5SDimitry Andric 952e8d8bef9SDimitry Andric encodeULEB128(Size, W->OS); 953e8d8bef9SDimitry Andric FuncSection.setSectionOffset(W->OS.tell() - Section.ContentsOffset); 954e8d8bef9SDimitry Andric Asm.writeSectionData(W->OS, &FuncSection, Layout); 9550b57cec5SDimitry Andric } 9560b57cec5SDimitry Andric 9570b57cec5SDimitry Andric // Apply fixups. 9585ffd83dbSDimitry Andric applyRelocations(CodeRelocations, Section.ContentsOffset, Layout); 9590b57cec5SDimitry Andric 9600b57cec5SDimitry Andric endSection(Section); 9615ffd83dbSDimitry Andric return Section.Index; 9620b57cec5SDimitry Andric } 9630b57cec5SDimitry Andric 9645ffd83dbSDimitry Andric uint32_t WasmObjectWriter::writeDataSection(const MCAsmLayout &Layout) { 9650b57cec5SDimitry Andric if (DataSegments.empty()) 9665ffd83dbSDimitry Andric return 0; 9670b57cec5SDimitry Andric 9680b57cec5SDimitry Andric SectionBookkeeping Section; 9690b57cec5SDimitry Andric startSection(Section, wasm::WASM_SEC_DATA); 9700b57cec5SDimitry Andric 971e8d8bef9SDimitry Andric encodeULEB128(DataSegments.size(), W->OS); // count 9720b57cec5SDimitry Andric 9730b57cec5SDimitry Andric for (const WasmDataSegment &Segment : DataSegments) { 974e8d8bef9SDimitry Andric encodeULEB128(Segment.InitFlags, W->OS); // flags 975e8d8bef9SDimitry Andric if (Segment.InitFlags & wasm::WASM_DATA_SEGMENT_HAS_MEMINDEX) 976e8d8bef9SDimitry Andric encodeULEB128(0, W->OS); // memory index 977e8d8bef9SDimitry Andric if ((Segment.InitFlags & wasm::WASM_DATA_SEGMENT_IS_PASSIVE) == 0) { 978e8d8bef9SDimitry Andric W->OS << char(Segment.Offset > INT32_MAX ? wasm::WASM_OPCODE_I64_CONST 9795ffd83dbSDimitry Andric : wasm::WASM_OPCODE_I32_CONST); 980e8d8bef9SDimitry Andric encodeSLEB128(Segment.Offset, W->OS); // offset 981e8d8bef9SDimitry Andric W->OS << char(wasm::WASM_OPCODE_END); 9820b57cec5SDimitry Andric } 983e8d8bef9SDimitry Andric encodeULEB128(Segment.Data.size(), W->OS); // size 984e8d8bef9SDimitry Andric Segment.Section->setSectionOffset(W->OS.tell() - Section.ContentsOffset); 985e8d8bef9SDimitry Andric W->OS << Segment.Data; // data 9860b57cec5SDimitry Andric } 9870b57cec5SDimitry Andric 9880b57cec5SDimitry Andric // Apply fixups. 9895ffd83dbSDimitry Andric applyRelocations(DataRelocations, Section.ContentsOffset, Layout); 9900b57cec5SDimitry Andric 9910b57cec5SDimitry Andric endSection(Section); 9925ffd83dbSDimitry Andric return Section.Index; 9930b57cec5SDimitry Andric } 9940b57cec5SDimitry Andric 9950b57cec5SDimitry Andric void WasmObjectWriter::writeRelocSection( 9960b57cec5SDimitry Andric uint32_t SectionIndex, StringRef Name, 9970b57cec5SDimitry Andric std::vector<WasmRelocationEntry> &Relocs) { 9980b57cec5SDimitry Andric // See: https://github.com/WebAssembly/tool-conventions/blob/master/Linking.md 9990b57cec5SDimitry Andric // for descriptions of the reloc sections. 10000b57cec5SDimitry Andric 10010b57cec5SDimitry Andric if (Relocs.empty()) 10020b57cec5SDimitry Andric return; 10030b57cec5SDimitry Andric 10040b57cec5SDimitry Andric // First, ensure the relocations are sorted in offset order. In general they 10050b57cec5SDimitry Andric // should already be sorted since `recordRelocation` is called in offset 10060b57cec5SDimitry Andric // order, but for the code section we combine many MC sections into single 10070b57cec5SDimitry Andric // wasm section, and this order is determined by the order of Asm.Symbols() 10080b57cec5SDimitry Andric // not the sections order. 10090b57cec5SDimitry Andric llvm::stable_sort( 10100b57cec5SDimitry Andric Relocs, [](const WasmRelocationEntry &A, const WasmRelocationEntry &B) { 10110b57cec5SDimitry Andric return (A.Offset + A.FixupSection->getSectionOffset()) < 10120b57cec5SDimitry Andric (B.Offset + B.FixupSection->getSectionOffset()); 10130b57cec5SDimitry Andric }); 10140b57cec5SDimitry Andric 10150b57cec5SDimitry Andric SectionBookkeeping Section; 10160b57cec5SDimitry Andric startCustomSection(Section, std::string("reloc.") + Name.str()); 10170b57cec5SDimitry Andric 1018e8d8bef9SDimitry Andric encodeULEB128(SectionIndex, W->OS); 1019e8d8bef9SDimitry Andric encodeULEB128(Relocs.size(), W->OS); 10200b57cec5SDimitry Andric for (const WasmRelocationEntry &RelEntry : Relocs) { 10210b57cec5SDimitry Andric uint64_t Offset = 10220b57cec5SDimitry Andric RelEntry.Offset + RelEntry.FixupSection->getSectionOffset(); 10230b57cec5SDimitry Andric uint32_t Index = getRelocationIndexValue(RelEntry); 10240b57cec5SDimitry Andric 1025e8d8bef9SDimitry Andric W->OS << char(RelEntry.Type); 1026e8d8bef9SDimitry Andric encodeULEB128(Offset, W->OS); 1027e8d8bef9SDimitry Andric encodeULEB128(Index, W->OS); 10280b57cec5SDimitry Andric if (RelEntry.hasAddend()) 1029e8d8bef9SDimitry Andric encodeSLEB128(RelEntry.Addend, W->OS); 10300b57cec5SDimitry Andric } 10310b57cec5SDimitry Andric 10320b57cec5SDimitry Andric endSection(Section); 10330b57cec5SDimitry Andric } 10340b57cec5SDimitry Andric 10350b57cec5SDimitry Andric void WasmObjectWriter::writeCustomRelocSections() { 10360b57cec5SDimitry Andric for (const auto &Sec : CustomSections) { 10370b57cec5SDimitry Andric auto &Relocations = CustomSectionsRelocations[Sec.Section]; 10380b57cec5SDimitry Andric writeRelocSection(Sec.OutputIndex, Sec.Name, Relocations); 10390b57cec5SDimitry Andric } 10400b57cec5SDimitry Andric } 10410b57cec5SDimitry Andric 10420b57cec5SDimitry Andric void WasmObjectWriter::writeLinkingMetaDataSection( 10430b57cec5SDimitry Andric ArrayRef<wasm::WasmSymbolInfo> SymbolInfos, 10440b57cec5SDimitry Andric ArrayRef<std::pair<uint16_t, uint32_t>> InitFuncs, 10450b57cec5SDimitry Andric const std::map<StringRef, std::vector<WasmComdatEntry>> &Comdats) { 10460b57cec5SDimitry Andric SectionBookkeeping Section; 10470b57cec5SDimitry Andric startCustomSection(Section, "linking"); 1048e8d8bef9SDimitry Andric encodeULEB128(wasm::WasmMetadataVersion, W->OS); 10490b57cec5SDimitry Andric 10500b57cec5SDimitry Andric SectionBookkeeping SubSection; 10510b57cec5SDimitry Andric if (SymbolInfos.size() != 0) { 10520b57cec5SDimitry Andric startSection(SubSection, wasm::WASM_SYMBOL_TABLE); 1053e8d8bef9SDimitry Andric encodeULEB128(SymbolInfos.size(), W->OS); 10540b57cec5SDimitry Andric for (const wasm::WasmSymbolInfo &Sym : SymbolInfos) { 1055e8d8bef9SDimitry Andric encodeULEB128(Sym.Kind, W->OS); 1056e8d8bef9SDimitry Andric encodeULEB128(Sym.Flags, W->OS); 10570b57cec5SDimitry Andric switch (Sym.Kind) { 10580b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_FUNCTION: 10590b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_GLOBAL: 10600b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_EVENT: 1061e8d8bef9SDimitry Andric case wasm::WASM_SYMBOL_TYPE_TABLE: 1062e8d8bef9SDimitry Andric encodeULEB128(Sym.ElementIndex, W->OS); 10630b57cec5SDimitry Andric if ((Sym.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0 || 10640b57cec5SDimitry Andric (Sym.Flags & wasm::WASM_SYMBOL_EXPLICIT_NAME) != 0) 10650b57cec5SDimitry Andric writeString(Sym.Name); 10660b57cec5SDimitry Andric break; 10670b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_DATA: 10680b57cec5SDimitry Andric writeString(Sym.Name); 10690b57cec5SDimitry Andric if ((Sym.Flags & wasm::WASM_SYMBOL_UNDEFINED) == 0) { 1070e8d8bef9SDimitry Andric encodeULEB128(Sym.DataRef.Segment, W->OS); 1071e8d8bef9SDimitry Andric encodeULEB128(Sym.DataRef.Offset, W->OS); 1072e8d8bef9SDimitry Andric encodeULEB128(Sym.DataRef.Size, W->OS); 10730b57cec5SDimitry Andric } 10740b57cec5SDimitry Andric break; 10750b57cec5SDimitry Andric case wasm::WASM_SYMBOL_TYPE_SECTION: { 10760b57cec5SDimitry Andric const uint32_t SectionIndex = 10770b57cec5SDimitry Andric CustomSections[Sym.ElementIndex].OutputIndex; 1078e8d8bef9SDimitry Andric encodeULEB128(SectionIndex, W->OS); 10790b57cec5SDimitry Andric break; 10800b57cec5SDimitry Andric } 10810b57cec5SDimitry Andric default: 10820b57cec5SDimitry Andric llvm_unreachable("unexpected kind"); 10830b57cec5SDimitry Andric } 10840b57cec5SDimitry Andric } 10850b57cec5SDimitry Andric endSection(SubSection); 10860b57cec5SDimitry Andric } 10870b57cec5SDimitry Andric 10880b57cec5SDimitry Andric if (DataSegments.size()) { 10890b57cec5SDimitry Andric startSection(SubSection, wasm::WASM_SEGMENT_INFO); 1090e8d8bef9SDimitry Andric encodeULEB128(DataSegments.size(), W->OS); 10910b57cec5SDimitry Andric for (const WasmDataSegment &Segment : DataSegments) { 10920b57cec5SDimitry Andric writeString(Segment.Name); 1093e8d8bef9SDimitry Andric encodeULEB128(Segment.Alignment, W->OS); 1094e8d8bef9SDimitry Andric encodeULEB128(Segment.LinkerFlags, W->OS); 10950b57cec5SDimitry Andric } 10960b57cec5SDimitry Andric endSection(SubSection); 10970b57cec5SDimitry Andric } 10980b57cec5SDimitry Andric 10990b57cec5SDimitry Andric if (!InitFuncs.empty()) { 11000b57cec5SDimitry Andric startSection(SubSection, wasm::WASM_INIT_FUNCS); 1101e8d8bef9SDimitry Andric encodeULEB128(InitFuncs.size(), W->OS); 11020b57cec5SDimitry Andric for (auto &StartFunc : InitFuncs) { 1103e8d8bef9SDimitry Andric encodeULEB128(StartFunc.first, W->OS); // priority 1104e8d8bef9SDimitry Andric encodeULEB128(StartFunc.second, W->OS); // function index 11050b57cec5SDimitry Andric } 11060b57cec5SDimitry Andric endSection(SubSection); 11070b57cec5SDimitry Andric } 11080b57cec5SDimitry Andric 11090b57cec5SDimitry Andric if (Comdats.size()) { 11100b57cec5SDimitry Andric startSection(SubSection, wasm::WASM_COMDAT_INFO); 1111e8d8bef9SDimitry Andric encodeULEB128(Comdats.size(), W->OS); 11120b57cec5SDimitry Andric for (const auto &C : Comdats) { 11130b57cec5SDimitry Andric writeString(C.first); 1114e8d8bef9SDimitry Andric encodeULEB128(0, W->OS); // flags for future use 1115e8d8bef9SDimitry Andric encodeULEB128(C.second.size(), W->OS); 11160b57cec5SDimitry Andric for (const WasmComdatEntry &Entry : C.second) { 1117e8d8bef9SDimitry Andric encodeULEB128(Entry.Kind, W->OS); 1118e8d8bef9SDimitry Andric encodeULEB128(Entry.Index, W->OS); 11190b57cec5SDimitry Andric } 11200b57cec5SDimitry Andric } 11210b57cec5SDimitry Andric endSection(SubSection); 11220b57cec5SDimitry Andric } 11230b57cec5SDimitry Andric 11240b57cec5SDimitry Andric endSection(Section); 11250b57cec5SDimitry Andric } 11260b57cec5SDimitry Andric 11270b57cec5SDimitry Andric void WasmObjectWriter::writeCustomSection(WasmCustomSection &CustomSection, 11280b57cec5SDimitry Andric const MCAssembler &Asm, 11290b57cec5SDimitry Andric const MCAsmLayout &Layout) { 11300b57cec5SDimitry Andric SectionBookkeeping Section; 11310b57cec5SDimitry Andric auto *Sec = CustomSection.Section; 11320b57cec5SDimitry Andric startCustomSection(Section, CustomSection.Name); 11330b57cec5SDimitry Andric 1134e8d8bef9SDimitry Andric Sec->setSectionOffset(W->OS.tell() - Section.ContentsOffset); 1135e8d8bef9SDimitry Andric Asm.writeSectionData(W->OS, Sec, Layout); 11360b57cec5SDimitry Andric 11370b57cec5SDimitry Andric CustomSection.OutputContentsOffset = Section.ContentsOffset; 11380b57cec5SDimitry Andric CustomSection.OutputIndex = Section.Index; 11390b57cec5SDimitry Andric 11400b57cec5SDimitry Andric endSection(Section); 11410b57cec5SDimitry Andric 11420b57cec5SDimitry Andric // Apply fixups. 11430b57cec5SDimitry Andric auto &Relocations = CustomSectionsRelocations[CustomSection.Section]; 11445ffd83dbSDimitry Andric applyRelocations(Relocations, CustomSection.OutputContentsOffset, Layout); 11450b57cec5SDimitry Andric } 11460b57cec5SDimitry Andric 11470b57cec5SDimitry Andric uint32_t WasmObjectWriter::getFunctionType(const MCSymbolWasm &Symbol) { 11480b57cec5SDimitry Andric assert(Symbol.isFunction()); 11490b57cec5SDimitry Andric assert(TypeIndices.count(&Symbol)); 11500b57cec5SDimitry Andric return TypeIndices[&Symbol]; 11510b57cec5SDimitry Andric } 11520b57cec5SDimitry Andric 11530b57cec5SDimitry Andric uint32_t WasmObjectWriter::getEventType(const MCSymbolWasm &Symbol) { 11540b57cec5SDimitry Andric assert(Symbol.isEvent()); 11550b57cec5SDimitry Andric assert(TypeIndices.count(&Symbol)); 11560b57cec5SDimitry Andric return TypeIndices[&Symbol]; 11570b57cec5SDimitry Andric } 11580b57cec5SDimitry Andric 11590b57cec5SDimitry Andric void WasmObjectWriter::registerFunctionType(const MCSymbolWasm &Symbol) { 11600b57cec5SDimitry Andric assert(Symbol.isFunction()); 11610b57cec5SDimitry Andric 1162e8d8bef9SDimitry Andric wasm::WasmSignature S; 11635ffd83dbSDimitry Andric 11645ffd83dbSDimitry Andric if (auto *Sig = Symbol.getSignature()) { 11650b57cec5SDimitry Andric S.Returns = Sig->Returns; 11660b57cec5SDimitry Andric S.Params = Sig->Params; 11670b57cec5SDimitry Andric } 11680b57cec5SDimitry Andric 11690b57cec5SDimitry Andric auto Pair = SignatureIndices.insert(std::make_pair(S, Signatures.size())); 11700b57cec5SDimitry Andric if (Pair.second) 11710b57cec5SDimitry Andric Signatures.push_back(S); 11720b57cec5SDimitry Andric TypeIndices[&Symbol] = Pair.first->second; 11730b57cec5SDimitry Andric 11740b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "registerFunctionType: " << Symbol 11750b57cec5SDimitry Andric << " new:" << Pair.second << "\n"); 11760b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> type index: " << Pair.first->second << "\n"); 11770b57cec5SDimitry Andric } 11780b57cec5SDimitry Andric 11790b57cec5SDimitry Andric void WasmObjectWriter::registerEventType(const MCSymbolWasm &Symbol) { 11800b57cec5SDimitry Andric assert(Symbol.isEvent()); 11810b57cec5SDimitry Andric 11820b57cec5SDimitry Andric // TODO Currently we don't generate imported exceptions, but if we do, we 11830b57cec5SDimitry Andric // should have a way of infering types of imported exceptions. 1184e8d8bef9SDimitry Andric wasm::WasmSignature S; 11850b57cec5SDimitry Andric if (auto *Sig = Symbol.getSignature()) { 11860b57cec5SDimitry Andric S.Returns = Sig->Returns; 11870b57cec5SDimitry Andric S.Params = Sig->Params; 11880b57cec5SDimitry Andric } 11890b57cec5SDimitry Andric 11900b57cec5SDimitry Andric auto Pair = SignatureIndices.insert(std::make_pair(S, Signatures.size())); 11910b57cec5SDimitry Andric if (Pair.second) 11920b57cec5SDimitry Andric Signatures.push_back(S); 11930b57cec5SDimitry Andric TypeIndices[&Symbol] = Pair.first->second; 11940b57cec5SDimitry Andric 11950b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "registerEventType: " << Symbol << " new:" << Pair.second 11960b57cec5SDimitry Andric << "\n"); 11970b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> type index: " << Pair.first->second << "\n"); 11980b57cec5SDimitry Andric } 11990b57cec5SDimitry Andric 12000b57cec5SDimitry Andric static bool isInSymtab(const MCSymbolWasm &Sym) { 12015ffd83dbSDimitry Andric if (Sym.isUsedInReloc() || Sym.isUsedInInitArray()) 12020b57cec5SDimitry Andric return true; 12030b57cec5SDimitry Andric 12040b57cec5SDimitry Andric if (Sym.isComdat() && !Sym.isDefined()) 12050b57cec5SDimitry Andric return false; 12060b57cec5SDimitry Andric 12075ffd83dbSDimitry Andric if (Sym.isTemporary()) 12080b57cec5SDimitry Andric return false; 12090b57cec5SDimitry Andric 12100b57cec5SDimitry Andric if (Sym.isSection()) 12110b57cec5SDimitry Andric return false; 12120b57cec5SDimitry Andric 12130b57cec5SDimitry Andric return true; 12140b57cec5SDimitry Andric } 12150b57cec5SDimitry Andric 1216e8d8bef9SDimitry Andric void WasmObjectWriter::prepareImports( 1217e8d8bef9SDimitry Andric SmallVectorImpl<wasm::WasmImport> &Imports, MCAssembler &Asm, 12180b57cec5SDimitry Andric const MCAsmLayout &Layout) { 12190b57cec5SDimitry Andric // For now, always emit the memory import, since loads and stores are not 12200b57cec5SDimitry Andric // valid without it. In the future, we could perhaps be more clever and omit 12210b57cec5SDimitry Andric // it if there are no loads or stores. 12220b57cec5SDimitry Andric wasm::WasmImport MemImport; 12230b57cec5SDimitry Andric MemImport.Module = "env"; 12240b57cec5SDimitry Andric MemImport.Field = "__linear_memory"; 12250b57cec5SDimitry Andric MemImport.Kind = wasm::WASM_EXTERNAL_MEMORY; 12265ffd83dbSDimitry Andric MemImport.Memory.Flags = is64Bit() ? wasm::WASM_LIMITS_FLAG_IS_64 12275ffd83dbSDimitry Andric : wasm::WASM_LIMITS_FLAG_NONE; 12280b57cec5SDimitry Andric Imports.push_back(MemImport); 12290b57cec5SDimitry Andric 12300b57cec5SDimitry Andric // Populate SignatureIndices, and Imports and WasmIndices for undefined 12310b57cec5SDimitry Andric // symbols. This must be done before populating WasmIndices for defined 12320b57cec5SDimitry Andric // symbols. 12330b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 12340b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 12350b57cec5SDimitry Andric 12360b57cec5SDimitry Andric // Register types for all functions, including those with private linkage 12370b57cec5SDimitry Andric // (because wasm always needs a type signature). 12385ffd83dbSDimitry Andric if (WS.isFunction()) { 1239e8d8bef9SDimitry Andric const auto *BS = Layout.getBaseSymbol(S); 1240e8d8bef9SDimitry Andric if (!BS) 1241e8d8bef9SDimitry Andric report_fatal_error(Twine(S.getName()) + 1242e8d8bef9SDimitry Andric ": absolute addressing not supported!"); 1243e8d8bef9SDimitry Andric registerFunctionType(*cast<MCSymbolWasm>(BS)); 12445ffd83dbSDimitry Andric } 12450b57cec5SDimitry Andric 12460b57cec5SDimitry Andric if (WS.isEvent()) 12470b57cec5SDimitry Andric registerEventType(WS); 12480b57cec5SDimitry Andric 12490b57cec5SDimitry Andric if (WS.isTemporary()) 12500b57cec5SDimitry Andric continue; 12510b57cec5SDimitry Andric 12520b57cec5SDimitry Andric // If the symbol is not defined in this translation unit, import it. 12530b57cec5SDimitry Andric if (!WS.isDefined() && !WS.isComdat()) { 12540b57cec5SDimitry Andric if (WS.isFunction()) { 12550b57cec5SDimitry Andric wasm::WasmImport Import; 12560b57cec5SDimitry Andric Import.Module = WS.getImportModule(); 12570b57cec5SDimitry Andric Import.Field = WS.getImportName(); 12580b57cec5SDimitry Andric Import.Kind = wasm::WASM_EXTERNAL_FUNCTION; 12590b57cec5SDimitry Andric Import.SigIndex = getFunctionType(WS); 12600b57cec5SDimitry Andric Imports.push_back(Import); 12610b57cec5SDimitry Andric assert(WasmIndices.count(&WS) == 0); 12620b57cec5SDimitry Andric WasmIndices[&WS] = NumFunctionImports++; 12630b57cec5SDimitry Andric } else if (WS.isGlobal()) { 12640b57cec5SDimitry Andric if (WS.isWeak()) 12650b57cec5SDimitry Andric report_fatal_error("undefined global symbol cannot be weak"); 12660b57cec5SDimitry Andric 12670b57cec5SDimitry Andric wasm::WasmImport Import; 12680b57cec5SDimitry Andric Import.Field = WS.getImportName(); 12690b57cec5SDimitry Andric Import.Kind = wasm::WASM_EXTERNAL_GLOBAL; 12700b57cec5SDimitry Andric Import.Module = WS.getImportModule(); 12710b57cec5SDimitry Andric Import.Global = WS.getGlobalType(); 12720b57cec5SDimitry Andric Imports.push_back(Import); 12730b57cec5SDimitry Andric assert(WasmIndices.count(&WS) == 0); 12740b57cec5SDimitry Andric WasmIndices[&WS] = NumGlobalImports++; 12750b57cec5SDimitry Andric } else if (WS.isEvent()) { 12760b57cec5SDimitry Andric if (WS.isWeak()) 12770b57cec5SDimitry Andric report_fatal_error("undefined event symbol cannot be weak"); 12780b57cec5SDimitry Andric 12790b57cec5SDimitry Andric wasm::WasmImport Import; 12800b57cec5SDimitry Andric Import.Module = WS.getImportModule(); 12810b57cec5SDimitry Andric Import.Field = WS.getImportName(); 12820b57cec5SDimitry Andric Import.Kind = wasm::WASM_EXTERNAL_EVENT; 12830b57cec5SDimitry Andric Import.Event.Attribute = wasm::WASM_EVENT_ATTRIBUTE_EXCEPTION; 12840b57cec5SDimitry Andric Import.Event.SigIndex = getEventType(WS); 12850b57cec5SDimitry Andric Imports.push_back(Import); 12860b57cec5SDimitry Andric assert(WasmIndices.count(&WS) == 0); 12870b57cec5SDimitry Andric WasmIndices[&WS] = NumEventImports++; 1288e8d8bef9SDimitry Andric } else if (WS.isTable()) { 1289e8d8bef9SDimitry Andric if (WS.isWeak()) 1290e8d8bef9SDimitry Andric report_fatal_error("undefined table symbol cannot be weak"); 1291e8d8bef9SDimitry Andric 1292e8d8bef9SDimitry Andric wasm::WasmImport Import; 1293e8d8bef9SDimitry Andric Import.Module = WS.getImportModule(); 1294e8d8bef9SDimitry Andric Import.Field = WS.getImportName(); 1295e8d8bef9SDimitry Andric Import.Kind = wasm::WASM_EXTERNAL_TABLE; 1296e8d8bef9SDimitry Andric wasm::ValType ElemType = WS.getTableType(); 1297e8d8bef9SDimitry Andric Import.Table.ElemType = uint8_t(ElemType); 1298e8d8bef9SDimitry Andric // FIXME: Extend table type to include limits? For now we don't specify 1299e8d8bef9SDimitry Andric // a min or max which does not place any restrictions on the size of the 1300e8d8bef9SDimitry Andric // imported table. 1301e8d8bef9SDimitry Andric Import.Table.Limits = {wasm::WASM_LIMITS_FLAG_NONE, 0, 0}; 1302e8d8bef9SDimitry Andric Imports.push_back(Import); 1303e8d8bef9SDimitry Andric assert(WasmIndices.count(&WS) == 0); 1304e8d8bef9SDimitry Andric WasmIndices[&WS] = NumTableImports++; 13050b57cec5SDimitry Andric } 13060b57cec5SDimitry Andric } 13070b57cec5SDimitry Andric } 13080b57cec5SDimitry Andric 13090b57cec5SDimitry Andric // Add imports for GOT globals 13100b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 13110b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 13120b57cec5SDimitry Andric if (WS.isUsedInGOT()) { 13130b57cec5SDimitry Andric wasm::WasmImport Import; 13140b57cec5SDimitry Andric if (WS.isFunction()) 13150b57cec5SDimitry Andric Import.Module = "GOT.func"; 13160b57cec5SDimitry Andric else 13170b57cec5SDimitry Andric Import.Module = "GOT.mem"; 13180b57cec5SDimitry Andric Import.Field = WS.getName(); 13190b57cec5SDimitry Andric Import.Kind = wasm::WASM_EXTERNAL_GLOBAL; 13200b57cec5SDimitry Andric Import.Global = {wasm::WASM_TYPE_I32, true}; 13210b57cec5SDimitry Andric Imports.push_back(Import); 13220b57cec5SDimitry Andric assert(GOTIndices.count(&WS) == 0); 13230b57cec5SDimitry Andric GOTIndices[&WS] = NumGlobalImports++; 13240b57cec5SDimitry Andric } 13250b57cec5SDimitry Andric } 1326e8d8bef9SDimitry Andric } 1327e8d8bef9SDimitry Andric 1328e8d8bef9SDimitry Andric uint64_t WasmObjectWriter::writeObject(MCAssembler &Asm, 1329e8d8bef9SDimitry Andric const MCAsmLayout &Layout) { 1330e8d8bef9SDimitry Andric support::endian::Writer MainWriter(*OS, support::little); 1331e8d8bef9SDimitry Andric W = &MainWriter; 1332e8d8bef9SDimitry Andric if (IsSplitDwarf) { 1333e8d8bef9SDimitry Andric uint64_t TotalSize = writeOneObject(Asm, Layout, DwoMode::NonDwoOnly); 1334e8d8bef9SDimitry Andric assert(DwoOS); 1335e8d8bef9SDimitry Andric support::endian::Writer DwoWriter(*DwoOS, support::little); 1336e8d8bef9SDimitry Andric W = &DwoWriter; 1337e8d8bef9SDimitry Andric return TotalSize + writeOneObject(Asm, Layout, DwoMode::DwoOnly); 1338e8d8bef9SDimitry Andric } else { 1339e8d8bef9SDimitry Andric return writeOneObject(Asm, Layout, DwoMode::AllSections); 1340e8d8bef9SDimitry Andric } 1341e8d8bef9SDimitry Andric } 1342e8d8bef9SDimitry Andric 1343e8d8bef9SDimitry Andric uint64_t WasmObjectWriter::writeOneObject(MCAssembler &Asm, 1344e8d8bef9SDimitry Andric const MCAsmLayout &Layout, 1345e8d8bef9SDimitry Andric DwoMode Mode) { 1346e8d8bef9SDimitry Andric uint64_t StartOffset = W->OS.tell(); 1347e8d8bef9SDimitry Andric SectionCount = 0; 1348e8d8bef9SDimitry Andric CustomSections.clear(); 1349e8d8bef9SDimitry Andric 1350e8d8bef9SDimitry Andric LLVM_DEBUG(dbgs() << "WasmObjectWriter::writeObject\n"); 1351e8d8bef9SDimitry Andric 1352e8d8bef9SDimitry Andric // Collect information from the available symbols. 1353e8d8bef9SDimitry Andric SmallVector<WasmFunction, 4> Functions; 1354e8d8bef9SDimitry Andric SmallVector<uint32_t, 4> TableElems; 1355e8d8bef9SDimitry Andric SmallVector<wasm::WasmImport, 4> Imports; 1356e8d8bef9SDimitry Andric SmallVector<wasm::WasmExport, 4> Exports; 1357e8d8bef9SDimitry Andric SmallVector<wasm::WasmEventType, 1> Events; 1358e8d8bef9SDimitry Andric SmallVector<wasm::WasmGlobal, 1> Globals; 1359e8d8bef9SDimitry Andric SmallVector<wasm::WasmTable, 1> Tables; 1360e8d8bef9SDimitry Andric SmallVector<wasm::WasmSymbolInfo, 4> SymbolInfos; 1361e8d8bef9SDimitry Andric SmallVector<std::pair<uint16_t, uint32_t>, 2> InitFuncs; 1362e8d8bef9SDimitry Andric std::map<StringRef, std::vector<WasmComdatEntry>> Comdats; 1363e8d8bef9SDimitry Andric uint64_t DataSize = 0; 1364e8d8bef9SDimitry Andric if (Mode != DwoMode::DwoOnly) { 1365e8d8bef9SDimitry Andric prepareImports(Imports, Asm, Layout); 1366e8d8bef9SDimitry Andric } 13670b57cec5SDimitry Andric 13680b57cec5SDimitry Andric // Populate DataSegments and CustomSections, which must be done before 13690b57cec5SDimitry Andric // populating DataLocations. 13700b57cec5SDimitry Andric for (MCSection &Sec : Asm) { 13710b57cec5SDimitry Andric auto &Section = static_cast<MCSectionWasm &>(Sec); 13725ffd83dbSDimitry Andric StringRef SectionName = Section.getName(); 13730b57cec5SDimitry Andric 1374e8d8bef9SDimitry Andric if (Mode == DwoMode::NonDwoOnly && isDwoSection(Sec)) 1375e8d8bef9SDimitry Andric continue; 1376e8d8bef9SDimitry Andric if (Mode == DwoMode::DwoOnly && !isDwoSection(Sec)) 1377e8d8bef9SDimitry Andric continue; 1378e8d8bef9SDimitry Andric 1379e8d8bef9SDimitry Andric LLVM_DEBUG(dbgs() << "Processing Section " << SectionName << " group " 1380e8d8bef9SDimitry Andric << Section.getGroup() << "\n";); 1381e8d8bef9SDimitry Andric 13820b57cec5SDimitry Andric // .init_array sections are handled specially elsewhere. 13830b57cec5SDimitry Andric if (SectionName.startswith(".init_array")) 13840b57cec5SDimitry Andric continue; 13850b57cec5SDimitry Andric 13860b57cec5SDimitry Andric // Code is handled separately 13870b57cec5SDimitry Andric if (Section.getKind().isText()) 13880b57cec5SDimitry Andric continue; 13890b57cec5SDimitry Andric 13900b57cec5SDimitry Andric if (Section.isWasmData()) { 13910b57cec5SDimitry Andric uint32_t SegmentIndex = DataSegments.size(); 13920b57cec5SDimitry Andric DataSize = alignTo(DataSize, Section.getAlignment()); 13930b57cec5SDimitry Andric DataSegments.emplace_back(); 13940b57cec5SDimitry Andric WasmDataSegment &Segment = DataSegments.back(); 13950b57cec5SDimitry Andric Segment.Name = SectionName; 1396e8d8bef9SDimitry Andric Segment.InitFlags = Section.getPassive() 1397e8d8bef9SDimitry Andric ? (uint32_t)wasm::WASM_DATA_SEGMENT_IS_PASSIVE 1398e8d8bef9SDimitry Andric : 0; 13990b57cec5SDimitry Andric Segment.Offset = DataSize; 14000b57cec5SDimitry Andric Segment.Section = &Section; 14010b57cec5SDimitry Andric addData(Segment.Data, Section); 14020b57cec5SDimitry Andric Segment.Alignment = Log2_32(Section.getAlignment()); 14030b57cec5SDimitry Andric Segment.LinkerFlags = 0; 14040b57cec5SDimitry Andric DataSize += Segment.Data.size(); 14050b57cec5SDimitry Andric Section.setSegmentIndex(SegmentIndex); 14060b57cec5SDimitry Andric 14070b57cec5SDimitry Andric if (const MCSymbolWasm *C = Section.getGroup()) { 14080b57cec5SDimitry Andric Comdats[C->getName()].emplace_back( 14090b57cec5SDimitry Andric WasmComdatEntry{wasm::WASM_COMDAT_DATA, SegmentIndex}); 14100b57cec5SDimitry Andric } 14110b57cec5SDimitry Andric } else { 14120b57cec5SDimitry Andric // Create custom sections 14130b57cec5SDimitry Andric assert(Sec.getKind().isMetadata()); 14140b57cec5SDimitry Andric 14150b57cec5SDimitry Andric StringRef Name = SectionName; 14160b57cec5SDimitry Andric 14170b57cec5SDimitry Andric // For user-defined custom sections, strip the prefix 14180b57cec5SDimitry Andric if (Name.startswith(".custom_section.")) 14190b57cec5SDimitry Andric Name = Name.substr(strlen(".custom_section.")); 14200b57cec5SDimitry Andric 14210b57cec5SDimitry Andric MCSymbol *Begin = Sec.getBeginSymbol(); 14220b57cec5SDimitry Andric if (Begin) { 1423e8d8bef9SDimitry Andric assert(WasmIndices.count(cast<MCSymbolWasm>(Begin)) == 0); 14240b57cec5SDimitry Andric WasmIndices[cast<MCSymbolWasm>(Begin)] = CustomSections.size(); 14250b57cec5SDimitry Andric } 14260b57cec5SDimitry Andric 14270b57cec5SDimitry Andric // Separate out the producers and target features sections 14280b57cec5SDimitry Andric if (Name == "producers") { 14298bcb0991SDimitry Andric ProducersSection = std::make_unique<WasmCustomSection>(Name, &Section); 14300b57cec5SDimitry Andric continue; 14310b57cec5SDimitry Andric } 14320b57cec5SDimitry Andric if (Name == "target_features") { 14330b57cec5SDimitry Andric TargetFeaturesSection = 14348bcb0991SDimitry Andric std::make_unique<WasmCustomSection>(Name, &Section); 14350b57cec5SDimitry Andric continue; 14360b57cec5SDimitry Andric } 14370b57cec5SDimitry Andric 1438e8d8bef9SDimitry Andric // Custom sections can also belong to COMDAT groups. In this case the 1439e8d8bef9SDimitry Andric // decriptor's "index" field is the section index (in the final object 1440e8d8bef9SDimitry Andric // file), but that is not known until after layout, so it must be fixed up 1441e8d8bef9SDimitry Andric // later 1442e8d8bef9SDimitry Andric if (const MCSymbolWasm *C = Section.getGroup()) { 1443e8d8bef9SDimitry Andric Comdats[C->getName()].emplace_back( 1444e8d8bef9SDimitry Andric WasmComdatEntry{wasm::WASM_COMDAT_SECTION, 1445e8d8bef9SDimitry Andric static_cast<uint32_t>(CustomSections.size())}); 1446e8d8bef9SDimitry Andric } 1447e8d8bef9SDimitry Andric 14480b57cec5SDimitry Andric CustomSections.emplace_back(Name, &Section); 14490b57cec5SDimitry Andric } 14500b57cec5SDimitry Andric } 14510b57cec5SDimitry Andric 1452e8d8bef9SDimitry Andric if (Mode != DwoMode::DwoOnly) { 14530b57cec5SDimitry Andric // Populate WasmIndices and DataLocations for defined symbols. 14540b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 14550b57cec5SDimitry Andric // Ignore unnamed temporary symbols, which aren't ever exported, imported, 14560b57cec5SDimitry Andric // or used in relocations. 14570b57cec5SDimitry Andric if (S.isTemporary() && S.getName().empty()) 14580b57cec5SDimitry Andric continue; 14590b57cec5SDimitry Andric 14600b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 14610b57cec5SDimitry Andric LLVM_DEBUG( 14620b57cec5SDimitry Andric dbgs() << "MCSymbol: " << toString(WS.getType()) << " '" << S << "'" 14630b57cec5SDimitry Andric << " isDefined=" << S.isDefined() << " isExternal=" 14640b57cec5SDimitry Andric << S.isExternal() << " isTemporary=" << S.isTemporary() 14650b57cec5SDimitry Andric << " isWeak=" << WS.isWeak() << " isHidden=" << WS.isHidden() 14660b57cec5SDimitry Andric << " isVariable=" << WS.isVariable() << "\n"); 14670b57cec5SDimitry Andric 14680b57cec5SDimitry Andric if (WS.isVariable()) 14690b57cec5SDimitry Andric continue; 14700b57cec5SDimitry Andric if (WS.isComdat() && !WS.isDefined()) 14710b57cec5SDimitry Andric continue; 14720b57cec5SDimitry Andric 14730b57cec5SDimitry Andric if (WS.isFunction()) { 14740b57cec5SDimitry Andric unsigned Index; 14750b57cec5SDimitry Andric if (WS.isDefined()) { 14760b57cec5SDimitry Andric if (WS.getOffset() != 0) 14770b57cec5SDimitry Andric report_fatal_error( 14780b57cec5SDimitry Andric "function sections must contain one function each"); 14790b57cec5SDimitry Andric 14800b57cec5SDimitry Andric if (WS.getSize() == nullptr) 14810b57cec5SDimitry Andric report_fatal_error( 14820b57cec5SDimitry Andric "function symbols must have a size set with .size"); 14830b57cec5SDimitry Andric 14840b57cec5SDimitry Andric // A definition. Write out the function body. 14850b57cec5SDimitry Andric Index = NumFunctionImports + Functions.size(); 14860b57cec5SDimitry Andric WasmFunction Func; 14870b57cec5SDimitry Andric Func.SigIndex = getFunctionType(WS); 14880b57cec5SDimitry Andric Func.Sym = &WS; 1489e8d8bef9SDimitry Andric assert(WasmIndices.count(&WS) == 0); 14900b57cec5SDimitry Andric WasmIndices[&WS] = Index; 14910b57cec5SDimitry Andric Functions.push_back(Func); 14920b57cec5SDimitry Andric 14930b57cec5SDimitry Andric auto &Section = static_cast<MCSectionWasm &>(WS.getSection()); 14940b57cec5SDimitry Andric if (const MCSymbolWasm *C = Section.getGroup()) { 14950b57cec5SDimitry Andric Comdats[C->getName()].emplace_back( 14960b57cec5SDimitry Andric WasmComdatEntry{wasm::WASM_COMDAT_FUNCTION, Index}); 14970b57cec5SDimitry Andric } 1498480093f4SDimitry Andric 1499480093f4SDimitry Andric if (WS.hasExportName()) { 1500480093f4SDimitry Andric wasm::WasmExport Export; 1501480093f4SDimitry Andric Export.Name = WS.getExportName(); 1502480093f4SDimitry Andric Export.Kind = wasm::WASM_EXTERNAL_FUNCTION; 1503480093f4SDimitry Andric Export.Index = Index; 1504480093f4SDimitry Andric Exports.push_back(Export); 1505480093f4SDimitry Andric } 15060b57cec5SDimitry Andric } else { 15070b57cec5SDimitry Andric // An import; the index was assigned above. 15080b57cec5SDimitry Andric Index = WasmIndices.find(&WS)->second; 15090b57cec5SDimitry Andric } 15100b57cec5SDimitry Andric 15110b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> function index: " << Index << "\n"); 15120b57cec5SDimitry Andric 15130b57cec5SDimitry Andric } else if (WS.isData()) { 15140b57cec5SDimitry Andric if (!isInSymtab(WS)) 15150b57cec5SDimitry Andric continue; 15160b57cec5SDimitry Andric 15170b57cec5SDimitry Andric if (!WS.isDefined()) { 15180b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> segment index: -1" 15190b57cec5SDimitry Andric << "\n"); 15200b57cec5SDimitry Andric continue; 15210b57cec5SDimitry Andric } 15220b57cec5SDimitry Andric 15230b57cec5SDimitry Andric if (!WS.getSize()) 15240b57cec5SDimitry Andric report_fatal_error("data symbols must have a size set with .size: " + 15250b57cec5SDimitry Andric WS.getName()); 15260b57cec5SDimitry Andric 15270b57cec5SDimitry Andric int64_t Size = 0; 15280b57cec5SDimitry Andric if (!WS.getSize()->evaluateAsAbsolute(Size, Layout)) 15290b57cec5SDimitry Andric report_fatal_error(".size expression must be evaluatable"); 15300b57cec5SDimitry Andric 15310b57cec5SDimitry Andric auto &DataSection = static_cast<MCSectionWasm &>(WS.getSection()); 15328bcb0991SDimitry Andric if (!DataSection.isWasmData()) 15338bcb0991SDimitry Andric report_fatal_error("data symbols must live in a data section: " + 15348bcb0991SDimitry Andric WS.getName()); 15350b57cec5SDimitry Andric 15360b57cec5SDimitry Andric // For each data symbol, export it in the symtab as a reference to the 15370b57cec5SDimitry Andric // corresponding Wasm data segment. 15380b57cec5SDimitry Andric wasm::WasmDataReference Ref = wasm::WasmDataReference{ 15395ffd83dbSDimitry Andric DataSection.getSegmentIndex(), Layout.getSymbolOffset(WS), 15405ffd83dbSDimitry Andric static_cast<uint64_t>(Size)}; 1541e8d8bef9SDimitry Andric assert(DataLocations.count(&WS) == 0); 15420b57cec5SDimitry Andric DataLocations[&WS] = Ref; 15430b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> segment index: " << Ref.Segment << "\n"); 15440b57cec5SDimitry Andric 15450b57cec5SDimitry Andric } else if (WS.isGlobal()) { 15460b57cec5SDimitry Andric // A "true" Wasm global (currently just __stack_pointer) 15475ffd83dbSDimitry Andric if (WS.isDefined()) { 15485ffd83dbSDimitry Andric wasm::WasmGlobal Global; 15495ffd83dbSDimitry Andric Global.Type = WS.getGlobalType(); 15505ffd83dbSDimitry Andric Global.Index = NumGlobalImports + Globals.size(); 15515ffd83dbSDimitry Andric switch (Global.Type.Type) { 15525ffd83dbSDimitry Andric case wasm::WASM_TYPE_I32: 15535ffd83dbSDimitry Andric Global.InitExpr.Opcode = wasm::WASM_OPCODE_I32_CONST; 15545ffd83dbSDimitry Andric break; 15555ffd83dbSDimitry Andric case wasm::WASM_TYPE_I64: 15565ffd83dbSDimitry Andric Global.InitExpr.Opcode = wasm::WASM_OPCODE_I64_CONST; 15575ffd83dbSDimitry Andric break; 15585ffd83dbSDimitry Andric case wasm::WASM_TYPE_F32: 15595ffd83dbSDimitry Andric Global.InitExpr.Opcode = wasm::WASM_OPCODE_F32_CONST; 15605ffd83dbSDimitry Andric break; 15615ffd83dbSDimitry Andric case wasm::WASM_TYPE_F64: 15625ffd83dbSDimitry Andric Global.InitExpr.Opcode = wasm::WASM_OPCODE_F64_CONST; 15635ffd83dbSDimitry Andric break; 15645ffd83dbSDimitry Andric case wasm::WASM_TYPE_EXTERNREF: 15655ffd83dbSDimitry Andric Global.InitExpr.Opcode = wasm::WASM_OPCODE_REF_NULL; 15665ffd83dbSDimitry Andric break; 15675ffd83dbSDimitry Andric default: 15685ffd83dbSDimitry Andric llvm_unreachable("unexpected type"); 15695ffd83dbSDimitry Andric } 1570e8d8bef9SDimitry Andric assert(WasmIndices.count(&WS) == 0); 15715ffd83dbSDimitry Andric WasmIndices[&WS] = Global.Index; 15725ffd83dbSDimitry Andric Globals.push_back(Global); 15735ffd83dbSDimitry Andric } else { 15740b57cec5SDimitry Andric // An import; the index was assigned above 15750b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> global index: " 15760b57cec5SDimitry Andric << WasmIndices.find(&WS)->second << "\n"); 15775ffd83dbSDimitry Andric } 1578e8d8bef9SDimitry Andric } else if (WS.isTable()) { 1579e8d8bef9SDimitry Andric if (WS.isDefined()) { 1580e8d8bef9SDimitry Andric wasm::WasmTable Table; 1581e8d8bef9SDimitry Andric Table.Index = NumTableImports + Tables.size(); 1582e8d8bef9SDimitry Andric Table.Type.ElemType = static_cast<uint8_t>(WS.getTableType()); 1583e8d8bef9SDimitry Andric // FIXME: Work on custom limits is ongoing 1584e8d8bef9SDimitry Andric Table.Type.Limits = {wasm::WASM_LIMITS_FLAG_NONE, 0, 0}; 1585e8d8bef9SDimitry Andric assert(WasmIndices.count(&WS) == 0); 1586e8d8bef9SDimitry Andric WasmIndices[&WS] = Table.Index; 1587e8d8bef9SDimitry Andric Tables.push_back(Table); 1588e8d8bef9SDimitry Andric } 1589e8d8bef9SDimitry Andric LLVM_DEBUG(dbgs() << " -> table index: " 1590e8d8bef9SDimitry Andric << WasmIndices.find(&WS)->second << "\n"); 15910b57cec5SDimitry Andric } else if (WS.isEvent()) { 15920b57cec5SDimitry Andric // C++ exception symbol (__cpp_exception) 15930b57cec5SDimitry Andric unsigned Index; 15940b57cec5SDimitry Andric if (WS.isDefined()) { 15950b57cec5SDimitry Andric Index = NumEventImports + Events.size(); 15960b57cec5SDimitry Andric wasm::WasmEventType Event; 15970b57cec5SDimitry Andric Event.SigIndex = getEventType(WS); 15980b57cec5SDimitry Andric Event.Attribute = wasm::WASM_EVENT_ATTRIBUTE_EXCEPTION; 1599e8d8bef9SDimitry Andric assert(WasmIndices.count(&WS) == 0); 16000b57cec5SDimitry Andric WasmIndices[&WS] = Index; 16010b57cec5SDimitry Andric Events.push_back(Event); 16020b57cec5SDimitry Andric } else { 16030b57cec5SDimitry Andric // An import; the index was assigned above. 16040b57cec5SDimitry Andric assert(WasmIndices.count(&WS) > 0); 16050b57cec5SDimitry Andric } 1606e8d8bef9SDimitry Andric LLVM_DEBUG(dbgs() << " -> event index: " 1607e8d8bef9SDimitry Andric << WasmIndices.find(&WS)->second << "\n"); 16080b57cec5SDimitry Andric 16090b57cec5SDimitry Andric } else { 16100b57cec5SDimitry Andric assert(WS.isSection()); 16110b57cec5SDimitry Andric } 16120b57cec5SDimitry Andric } 16130b57cec5SDimitry Andric 16140b57cec5SDimitry Andric // Populate WasmIndices and DataLocations for aliased symbols. We need to 16150b57cec5SDimitry Andric // process these in a separate pass because we need to have processed the 16160b57cec5SDimitry Andric // target of the alias before the alias itself and the symbols are not 16170b57cec5SDimitry Andric // necessarily ordered in this way. 16180b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 16190b57cec5SDimitry Andric if (!S.isVariable()) 16200b57cec5SDimitry Andric continue; 16210b57cec5SDimitry Andric 16220b57cec5SDimitry Andric assert(S.isDefined()); 16230b57cec5SDimitry Andric 1624e8d8bef9SDimitry Andric const auto *BS = Layout.getBaseSymbol(S); 1625e8d8bef9SDimitry Andric if (!BS) 1626e8d8bef9SDimitry Andric report_fatal_error(Twine(S.getName()) + 1627e8d8bef9SDimitry Andric ": absolute addressing not supported!"); 1628e8d8bef9SDimitry Andric const MCSymbolWasm *Base = cast<MCSymbolWasm>(BS); 16295ffd83dbSDimitry Andric 16300b57cec5SDimitry Andric // Find the target symbol of this weak alias and export that index 16310b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 1632e8d8bef9SDimitry Andric LLVM_DEBUG(dbgs() << WS.getName() << ": weak alias of '" << *Base 1633e8d8bef9SDimitry Andric << "'\n"); 16340b57cec5SDimitry Andric 16355ffd83dbSDimitry Andric if (Base->isFunction()) { 16365ffd83dbSDimitry Andric assert(WasmIndices.count(Base) > 0); 16375ffd83dbSDimitry Andric uint32_t WasmIndex = WasmIndices.find(Base)->second; 16380b57cec5SDimitry Andric assert(WasmIndices.count(&WS) == 0); 16390b57cec5SDimitry Andric WasmIndices[&WS] = WasmIndex; 16400b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> index:" << WasmIndex << "\n"); 16415ffd83dbSDimitry Andric } else if (Base->isData()) { 16425ffd83dbSDimitry Andric auto &DataSection = static_cast<MCSectionWasm &>(WS.getSection()); 16435ffd83dbSDimitry Andric uint64_t Offset = Layout.getSymbolOffset(S); 16445ffd83dbSDimitry Andric int64_t Size = 0; 16455ffd83dbSDimitry Andric // For data symbol alias we use the size of the base symbol as the 16465ffd83dbSDimitry Andric // size of the alias. When an offset from the base is involved this 16475ffd83dbSDimitry Andric // can result in a offset + size goes past the end of the data section 16485ffd83dbSDimitry Andric // which out object format doesn't support. So we must clamp it. 16495ffd83dbSDimitry Andric if (!Base->getSize()->evaluateAsAbsolute(Size, Layout)) 16505ffd83dbSDimitry Andric report_fatal_error(".size expression must be evaluatable"); 16515ffd83dbSDimitry Andric const WasmDataSegment &Segment = 16525ffd83dbSDimitry Andric DataSegments[DataSection.getSegmentIndex()]; 16535ffd83dbSDimitry Andric Size = 16545ffd83dbSDimitry Andric std::min(static_cast<uint64_t>(Size), Segment.Data.size() - Offset); 16555ffd83dbSDimitry Andric wasm::WasmDataReference Ref = wasm::WasmDataReference{ 16565ffd83dbSDimitry Andric DataSection.getSegmentIndex(), 16575ffd83dbSDimitry Andric static_cast<uint32_t>(Layout.getSymbolOffset(S)), 16585ffd83dbSDimitry Andric static_cast<uint32_t>(Size)}; 16590b57cec5SDimitry Andric DataLocations[&WS] = Ref; 16600b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << " -> index:" << Ref.Segment << "\n"); 16610b57cec5SDimitry Andric } else { 16620b57cec5SDimitry Andric report_fatal_error("don't yet support global/event aliases"); 16630b57cec5SDimitry Andric } 16640b57cec5SDimitry Andric } 1665e8d8bef9SDimitry Andric } 16660b57cec5SDimitry Andric 16670b57cec5SDimitry Andric // Finally, populate the symbol table itself, in its "natural" order. 16680b57cec5SDimitry Andric for (const MCSymbol &S : Asm.symbols()) { 16690b57cec5SDimitry Andric const auto &WS = static_cast<const MCSymbolWasm &>(S); 16700b57cec5SDimitry Andric if (!isInSymtab(WS)) { 16710b57cec5SDimitry Andric WS.setIndex(InvalidIndex); 16720b57cec5SDimitry Andric continue; 16730b57cec5SDimitry Andric } 1674e8d8bef9SDimitry Andric if (WS.isTable() && WS.getName() == "__indirect_function_table") { 1675e8d8bef9SDimitry Andric // For the moment, don't emit table symbols -- wasm-ld can't handle them. 1676e8d8bef9SDimitry Andric continue; 1677e8d8bef9SDimitry Andric } 16780b57cec5SDimitry Andric LLVM_DEBUG(dbgs() << "adding to symtab: " << WS << "\n"); 16790b57cec5SDimitry Andric 16800b57cec5SDimitry Andric uint32_t Flags = 0; 16810b57cec5SDimitry Andric if (WS.isWeak()) 16820b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_BINDING_WEAK; 16830b57cec5SDimitry Andric if (WS.isHidden()) 16840b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_VISIBILITY_HIDDEN; 16850b57cec5SDimitry Andric if (!WS.isExternal() && WS.isDefined()) 16860b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_BINDING_LOCAL; 16870b57cec5SDimitry Andric if (WS.isUndefined()) 16880b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_UNDEFINED; 16898bcb0991SDimitry Andric if (WS.isNoStrip()) { 16908bcb0991SDimitry Andric Flags |= wasm::WASM_SYMBOL_NO_STRIP; 16918bcb0991SDimitry Andric if (isEmscripten()) { 16920b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_EXPORTED; 16938bcb0991SDimitry Andric } 16948bcb0991SDimitry Andric } 1695480093f4SDimitry Andric if (WS.hasImportName()) 16960b57cec5SDimitry Andric Flags |= wasm::WASM_SYMBOL_EXPLICIT_NAME; 1697480093f4SDimitry Andric if (WS.hasExportName()) 1698480093f4SDimitry Andric Flags |= wasm::WASM_SYMBOL_EXPORTED; 16990b57cec5SDimitry Andric 17000b57cec5SDimitry Andric wasm::WasmSymbolInfo Info; 17010b57cec5SDimitry Andric Info.Name = WS.getName(); 17020b57cec5SDimitry Andric Info.Kind = WS.getType(); 17030b57cec5SDimitry Andric Info.Flags = Flags; 17040b57cec5SDimitry Andric if (!WS.isData()) { 17050b57cec5SDimitry Andric assert(WasmIndices.count(&WS) > 0); 17060b57cec5SDimitry Andric Info.ElementIndex = WasmIndices.find(&WS)->second; 17070b57cec5SDimitry Andric } else if (WS.isDefined()) { 17080b57cec5SDimitry Andric assert(DataLocations.count(&WS) > 0); 17090b57cec5SDimitry Andric Info.DataRef = DataLocations.find(&WS)->second; 17100b57cec5SDimitry Andric } 17110b57cec5SDimitry Andric WS.setIndex(SymbolInfos.size()); 17120b57cec5SDimitry Andric SymbolInfos.emplace_back(Info); 17130b57cec5SDimitry Andric } 17140b57cec5SDimitry Andric 17150b57cec5SDimitry Andric { 17160b57cec5SDimitry Andric auto HandleReloc = [&](const WasmRelocationEntry &Rel) { 17170b57cec5SDimitry Andric // Functions referenced by a relocation need to put in the table. This is 17180b57cec5SDimitry Andric // purely to make the object file's provisional values readable, and is 17190b57cec5SDimitry Andric // ignored by the linker, which re-calculates the relocations itself. 17200b57cec5SDimitry Andric if (Rel.Type != wasm::R_WASM_TABLE_INDEX_I32 && 1721e8d8bef9SDimitry Andric Rel.Type != wasm::R_WASM_TABLE_INDEX_I64 && 17225ffd83dbSDimitry Andric Rel.Type != wasm::R_WASM_TABLE_INDEX_SLEB && 1723e8d8bef9SDimitry Andric Rel.Type != wasm::R_WASM_TABLE_INDEX_SLEB64 && 17245ffd83dbSDimitry Andric Rel.Type != wasm::R_WASM_TABLE_INDEX_REL_SLEB) 17250b57cec5SDimitry Andric return; 17260b57cec5SDimitry Andric assert(Rel.Symbol->isFunction()); 17275ffd83dbSDimitry Andric const MCSymbolWasm *Base = 17285ffd83dbSDimitry Andric cast<MCSymbolWasm>(Layout.getBaseSymbol(*Rel.Symbol)); 17295ffd83dbSDimitry Andric uint32_t FunctionIndex = WasmIndices.find(Base)->second; 17300b57cec5SDimitry Andric uint32_t TableIndex = TableElems.size() + InitialTableOffset; 17315ffd83dbSDimitry Andric if (TableIndices.try_emplace(Base, TableIndex).second) { 17325ffd83dbSDimitry Andric LLVM_DEBUG(dbgs() << " -> adding " << Base->getName() 17330b57cec5SDimitry Andric << " to table: " << TableIndex << "\n"); 17340b57cec5SDimitry Andric TableElems.push_back(FunctionIndex); 17355ffd83dbSDimitry Andric registerFunctionType(*Base); 17360b57cec5SDimitry Andric } 17370b57cec5SDimitry Andric }; 17380b57cec5SDimitry Andric 17390b57cec5SDimitry Andric for (const WasmRelocationEntry &RelEntry : CodeRelocations) 17400b57cec5SDimitry Andric HandleReloc(RelEntry); 17410b57cec5SDimitry Andric for (const WasmRelocationEntry &RelEntry : DataRelocations) 17420b57cec5SDimitry Andric HandleReloc(RelEntry); 17430b57cec5SDimitry Andric } 17440b57cec5SDimitry Andric 17450b57cec5SDimitry Andric // Translate .init_array section contents into start functions. 17460b57cec5SDimitry Andric for (const MCSection &S : Asm) { 17470b57cec5SDimitry Andric const auto &WS = static_cast<const MCSectionWasm &>(S); 17485ffd83dbSDimitry Andric if (WS.getName().startswith(".fini_array")) 17490b57cec5SDimitry Andric report_fatal_error(".fini_array sections are unsupported"); 17505ffd83dbSDimitry Andric if (!WS.getName().startswith(".init_array")) 17510b57cec5SDimitry Andric continue; 17520b57cec5SDimitry Andric if (WS.getFragmentList().empty()) 17530b57cec5SDimitry Andric continue; 17540b57cec5SDimitry Andric 17550b57cec5SDimitry Andric // init_array is expected to contain a single non-empty data fragment 17560b57cec5SDimitry Andric if (WS.getFragmentList().size() != 3) 17570b57cec5SDimitry Andric report_fatal_error("only one .init_array section fragment supported"); 17580b57cec5SDimitry Andric 17590b57cec5SDimitry Andric auto IT = WS.begin(); 17600b57cec5SDimitry Andric const MCFragment &EmptyFrag = *IT; 17610b57cec5SDimitry Andric if (EmptyFrag.getKind() != MCFragment::FT_Data) 17620b57cec5SDimitry Andric report_fatal_error(".init_array section should be aligned"); 17630b57cec5SDimitry Andric 17640b57cec5SDimitry Andric IT = std::next(IT); 17650b57cec5SDimitry Andric const MCFragment &AlignFrag = *IT; 17660b57cec5SDimitry Andric if (AlignFrag.getKind() != MCFragment::FT_Align) 17670b57cec5SDimitry Andric report_fatal_error(".init_array section should be aligned"); 17680b57cec5SDimitry Andric if (cast<MCAlignFragment>(AlignFrag).getAlignment() != (is64Bit() ? 8 : 4)) 17690b57cec5SDimitry Andric report_fatal_error(".init_array section should be aligned for pointers"); 17700b57cec5SDimitry Andric 17710b57cec5SDimitry Andric const MCFragment &Frag = *std::next(IT); 17720b57cec5SDimitry Andric if (Frag.hasInstructions() || Frag.getKind() != MCFragment::FT_Data) 17730b57cec5SDimitry Andric report_fatal_error("only data supported in .init_array section"); 17740b57cec5SDimitry Andric 17750b57cec5SDimitry Andric uint16_t Priority = UINT16_MAX; 17760b57cec5SDimitry Andric unsigned PrefixLength = strlen(".init_array"); 17775ffd83dbSDimitry Andric if (WS.getName().size() > PrefixLength) { 17785ffd83dbSDimitry Andric if (WS.getName()[PrefixLength] != '.') 17790b57cec5SDimitry Andric report_fatal_error( 17800b57cec5SDimitry Andric ".init_array section priority should start with '.'"); 17815ffd83dbSDimitry Andric if (WS.getName().substr(PrefixLength + 1).getAsInteger(10, Priority)) 17820b57cec5SDimitry Andric report_fatal_error("invalid .init_array section priority"); 17830b57cec5SDimitry Andric } 17840b57cec5SDimitry Andric const auto &DataFrag = cast<MCDataFragment>(Frag); 17850b57cec5SDimitry Andric const SmallVectorImpl<char> &Contents = DataFrag.getContents(); 17860b57cec5SDimitry Andric for (const uint8_t * 17870b57cec5SDimitry Andric P = (const uint8_t *)Contents.data(), 17880b57cec5SDimitry Andric *End = (const uint8_t *)Contents.data() + Contents.size(); 17890b57cec5SDimitry Andric P != End; ++P) { 17900b57cec5SDimitry Andric if (*P != 0) 17910b57cec5SDimitry Andric report_fatal_error("non-symbolic data in .init_array section"); 17920b57cec5SDimitry Andric } 17930b57cec5SDimitry Andric for (const MCFixup &Fixup : DataFrag.getFixups()) { 17940b57cec5SDimitry Andric assert(Fixup.getKind() == 17950b57cec5SDimitry Andric MCFixup::getKindForSize(is64Bit() ? 8 : 4, false)); 17960b57cec5SDimitry Andric const MCExpr *Expr = Fixup.getValue(); 17970b57cec5SDimitry Andric auto *SymRef = dyn_cast<MCSymbolRefExpr>(Expr); 17980b57cec5SDimitry Andric if (!SymRef) 17990b57cec5SDimitry Andric report_fatal_error("fixups in .init_array should be symbol references"); 18000b57cec5SDimitry Andric const auto &TargetSym = cast<const MCSymbolWasm>(SymRef->getSymbol()); 18010b57cec5SDimitry Andric if (TargetSym.getIndex() == InvalidIndex) 18025ffd83dbSDimitry Andric report_fatal_error("symbols in .init_array should exist in symtab"); 18030b57cec5SDimitry Andric if (!TargetSym.isFunction()) 18040b57cec5SDimitry Andric report_fatal_error("symbols in .init_array should be for functions"); 18050b57cec5SDimitry Andric InitFuncs.push_back( 18060b57cec5SDimitry Andric std::make_pair(Priority, TargetSym.getIndex())); 18070b57cec5SDimitry Andric } 18080b57cec5SDimitry Andric } 18090b57cec5SDimitry Andric 18100b57cec5SDimitry Andric // Write out the Wasm header. 18110b57cec5SDimitry Andric writeHeader(Asm); 18120b57cec5SDimitry Andric 1813e8d8bef9SDimitry Andric uint32_t CodeSectionIndex, DataSectionIndex; 1814e8d8bef9SDimitry Andric if (Mode != DwoMode::DwoOnly) { 18150b57cec5SDimitry Andric writeTypeSection(Signatures); 18160b57cec5SDimitry Andric writeImportSection(Imports, DataSize, TableElems.size()); 18170b57cec5SDimitry Andric writeFunctionSection(Functions); 1818e8d8bef9SDimitry Andric writeTableSection(Tables); 18190b57cec5SDimitry Andric // Skip the "memory" section; we import the memory instead. 18200b57cec5SDimitry Andric writeEventSection(Events); 18215ffd83dbSDimitry Andric writeGlobalSection(Globals); 18220b57cec5SDimitry Andric writeExportSection(Exports); 18230b57cec5SDimitry Andric writeElemSection(TableElems); 18240b57cec5SDimitry Andric writeDataCountSection(); 1825e8d8bef9SDimitry Andric 1826e8d8bef9SDimitry Andric CodeSectionIndex = writeCodeSection(Asm, Layout, Functions); 1827e8d8bef9SDimitry Andric DataSectionIndex = writeDataSection(Layout); 1828e8d8bef9SDimitry Andric } 1829e8d8bef9SDimitry Andric 1830e8d8bef9SDimitry Andric // The Sections in the COMDAT list have placeholder indices (their index among 1831e8d8bef9SDimitry Andric // custom sections, rather than among all sections). Fix them up here. 1832e8d8bef9SDimitry Andric for (auto &Group : Comdats) { 1833e8d8bef9SDimitry Andric for (auto &Entry : Group.second) { 1834e8d8bef9SDimitry Andric if (Entry.Kind == wasm::WASM_COMDAT_SECTION) { 1835e8d8bef9SDimitry Andric Entry.Index += SectionCount; 1836e8d8bef9SDimitry Andric } 1837e8d8bef9SDimitry Andric } 1838e8d8bef9SDimitry Andric } 18390b57cec5SDimitry Andric for (auto &CustomSection : CustomSections) 18400b57cec5SDimitry Andric writeCustomSection(CustomSection, Asm, Layout); 1841e8d8bef9SDimitry Andric 1842e8d8bef9SDimitry Andric if (Mode != DwoMode::DwoOnly) { 18430b57cec5SDimitry Andric writeLinkingMetaDataSection(SymbolInfos, InitFuncs, Comdats); 1844e8d8bef9SDimitry Andric 18450b57cec5SDimitry Andric writeRelocSection(CodeSectionIndex, "CODE", CodeRelocations); 18460b57cec5SDimitry Andric writeRelocSection(DataSectionIndex, "DATA", DataRelocations); 1847e8d8bef9SDimitry Andric } 18480b57cec5SDimitry Andric writeCustomRelocSections(); 18490b57cec5SDimitry Andric if (ProducersSection) 18500b57cec5SDimitry Andric writeCustomSection(*ProducersSection, Asm, Layout); 18510b57cec5SDimitry Andric if (TargetFeaturesSection) 18520b57cec5SDimitry Andric writeCustomSection(*TargetFeaturesSection, Asm, Layout); 18530b57cec5SDimitry Andric 18540b57cec5SDimitry Andric // TODO: Translate the .comment section to the output. 1855e8d8bef9SDimitry Andric return W->OS.tell() - StartOffset; 18560b57cec5SDimitry Andric } 18570b57cec5SDimitry Andric 18580b57cec5SDimitry Andric std::unique_ptr<MCObjectWriter> 18590b57cec5SDimitry Andric llvm::createWasmObjectWriter(std::unique_ptr<MCWasmObjectTargetWriter> MOTW, 18600b57cec5SDimitry Andric raw_pwrite_stream &OS) { 18618bcb0991SDimitry Andric return std::make_unique<WasmObjectWriter>(std::move(MOTW), OS); 18620b57cec5SDimitry Andric } 1863e8d8bef9SDimitry Andric 1864e8d8bef9SDimitry Andric std::unique_ptr<MCObjectWriter> 1865e8d8bef9SDimitry Andric llvm::createWasmDwoObjectWriter(std::unique_ptr<MCWasmObjectTargetWriter> MOTW, 1866e8d8bef9SDimitry Andric raw_pwrite_stream &OS, 1867e8d8bef9SDimitry Andric raw_pwrite_stream &DwoOS) { 1868e8d8bef9SDimitry Andric return std::make_unique<WasmObjectWriter>(std::move(MOTW), OS, DwoOS); 1869e8d8bef9SDimitry Andric } 1870