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Diffstat (limited to 'contrib/llvm/lib/MC/MachObjectWriter.cpp')
| -rw-r--r-- | contrib/llvm/lib/MC/MachObjectWriter.cpp | 1048 |
1 files changed, 0 insertions, 1048 deletions
diff --git a/contrib/llvm/lib/MC/MachObjectWriter.cpp b/contrib/llvm/lib/MC/MachObjectWriter.cpp deleted file mode 100644 index f0ceb86b25af..000000000000 --- a/contrib/llvm/lib/MC/MachObjectWriter.cpp +++ /dev/null @@ -1,1048 +0,0 @@ -//===- lib/MC/MachObjectWriter.cpp - Mach-O File Writer -------------------===// -// -// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. -// See https://llvm.org/LICENSE.txt for license information. -// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception -// -//===----------------------------------------------------------------------===// - -#include "llvm/ADT/DenseMap.h" -#include "llvm/ADT/Twine.h" -#include "llvm/ADT/iterator_range.h" -#include "llvm/BinaryFormat/MachO.h" -#include "llvm/MC/MCAsmBackend.h" -#include "llvm/MC/MCAsmLayout.h" -#include "llvm/MC/MCAssembler.h" -#include "llvm/MC/MCContext.h" -#include "llvm/MC/MCDirectives.h" -#include "llvm/MC/MCExpr.h" -#include "llvm/MC/MCFixupKindInfo.h" -#include "llvm/MC/MCFragment.h" -#include "llvm/MC/MCMachObjectWriter.h" -#include "llvm/MC/MCObjectWriter.h" -#include "llvm/MC/MCSection.h" -#include "llvm/MC/MCSectionMachO.h" -#include "llvm/MC/MCSymbol.h" -#include "llvm/MC/MCSymbolMachO.h" -#include "llvm/MC/MCValue.h" -#include "llvm/Support/Casting.h" -#include "llvm/Support/Debug.h" -#include "llvm/Support/ErrorHandling.h" -#include "llvm/Support/MathExtras.h" -#include "llvm/Support/raw_ostream.h" -#include <algorithm> -#include <cassert> -#include <cstdint> -#include <string> -#include <utility> -#include <vector> - -using namespace llvm; - -#define DEBUG_TYPE "mc" - -void MachObjectWriter::reset() { - Relocations.clear(); - IndirectSymBase.clear(); - StringTable.clear(); - LocalSymbolData.clear(); - ExternalSymbolData.clear(); - UndefinedSymbolData.clear(); - MCObjectWriter::reset(); -} - -bool MachObjectWriter::doesSymbolRequireExternRelocation(const MCSymbol &S) { - // Undefined symbols are always extern. - if (S.isUndefined()) - return true; - - // References to weak definitions require external relocation entries; the - // definition may not always be the one in the same object file. - if (cast<MCSymbolMachO>(S).isWeakDefinition()) - return true; - - // Otherwise, we can use an internal relocation. - return false; -} - -bool MachObjectWriter:: -MachSymbolData::operator<(const MachSymbolData &RHS) const { - return Symbol->getName() < RHS.Symbol->getName(); -} - -bool MachObjectWriter::isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) { - const MCFixupKindInfo &FKI = Asm.getBackend().getFixupKindInfo( - (MCFixupKind) Kind); - - return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel; -} - -uint64_t MachObjectWriter::getFragmentAddress(const MCFragment *Fragment, - const MCAsmLayout &Layout) const { - return getSectionAddress(Fragment->getParent()) + - Layout.getFragmentOffset(Fragment); -} - -uint64_t MachObjectWriter::getSymbolAddress(const MCSymbol &S, - const MCAsmLayout &Layout) const { - // If this is a variable, then recursively evaluate now. - if (S.isVariable()) { - if (const MCConstantExpr *C = - dyn_cast<const MCConstantExpr>(S.getVariableValue())) - return C->getValue(); - - MCValue Target; - if (!S.getVariableValue()->evaluateAsRelocatable(Target, &Layout, nullptr)) - report_fatal_error("unable to evaluate offset for variable '" + - S.getName() + "'"); - - // Verify that any used symbols are defined. - if (Target.getSymA() && Target.getSymA()->getSymbol().isUndefined()) - report_fatal_error("unable to evaluate offset to undefined symbol '" + - Target.getSymA()->getSymbol().getName() + "'"); - if (Target.getSymB() && Target.getSymB()->getSymbol().isUndefined()) - report_fatal_error("unable to evaluate offset to undefined symbol '" + - Target.getSymB()->getSymbol().getName() + "'"); - - uint64_t Address = Target.getConstant(); - if (Target.getSymA()) - Address += getSymbolAddress(Target.getSymA()->getSymbol(), Layout); - if (Target.getSymB()) - Address += getSymbolAddress(Target.getSymB()->getSymbol(), Layout); - return Address; - } - - return getSectionAddress(S.getFragment()->getParent()) + - Layout.getSymbolOffset(S); -} - -uint64_t MachObjectWriter::getPaddingSize(const MCSection *Sec, - const MCAsmLayout &Layout) const { - uint64_t EndAddr = getSectionAddress(Sec) + Layout.getSectionAddressSize(Sec); - unsigned Next = Sec->getLayoutOrder() + 1; - if (Next >= Layout.getSectionOrder().size()) - return 0; - - const MCSection &NextSec = *Layout.getSectionOrder()[Next]; - if (NextSec.isVirtualSection()) - return 0; - return OffsetToAlignment(EndAddr, NextSec.getAlignment()); -} - -void MachObjectWriter::writeHeader(MachO::HeaderFileType Type, - unsigned NumLoadCommands, - unsigned LoadCommandsSize, - bool SubsectionsViaSymbols) { - uint32_t Flags = 0; - - if (SubsectionsViaSymbols) - Flags |= MachO::MH_SUBSECTIONS_VIA_SYMBOLS; - - // struct mach_header (28 bytes) or - // struct mach_header_64 (32 bytes) - - uint64_t Start = W.OS.tell(); - (void) Start; - - W.write<uint32_t>(is64Bit() ? MachO::MH_MAGIC_64 : MachO::MH_MAGIC); - - W.write<uint32_t>(TargetObjectWriter->getCPUType()); - W.write<uint32_t>(TargetObjectWriter->getCPUSubtype()); - - W.write<uint32_t>(Type); - W.write<uint32_t>(NumLoadCommands); - W.write<uint32_t>(LoadCommandsSize); - W.write<uint32_t>(Flags); - if (is64Bit()) - W.write<uint32_t>(0); // reserved - - assert(W.OS.tell() - Start == (is64Bit() ? sizeof(MachO::mach_header_64) - : sizeof(MachO::mach_header))); -} - -void MachObjectWriter::writeWithPadding(StringRef Str, uint64_t Size) { - assert(Size >= Str.size()); - W.OS << Str; - W.OS.write_zeros(Size - Str.size()); -} - -/// writeSegmentLoadCommand - Write a segment load command. -/// -/// \param NumSections The number of sections in this segment. -/// \param SectionDataSize The total size of the sections. -void MachObjectWriter::writeSegmentLoadCommand( - StringRef Name, unsigned NumSections, uint64_t VMAddr, uint64_t VMSize, - uint64_t SectionDataStartOffset, uint64_t SectionDataSize, uint32_t MaxProt, - uint32_t InitProt) { - // struct segment_command (56 bytes) or - // struct segment_command_64 (72 bytes) - - uint64_t Start = W.OS.tell(); - (void) Start; - - unsigned SegmentLoadCommandSize = - is64Bit() ? sizeof(MachO::segment_command_64): - sizeof(MachO::segment_command); - W.write<uint32_t>(is64Bit() ? MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT); - W.write<uint32_t>(SegmentLoadCommandSize + - NumSections * (is64Bit() ? sizeof(MachO::section_64) : - sizeof(MachO::section))); - - writeWithPadding(Name, 16); - if (is64Bit()) { - W.write<uint64_t>(VMAddr); // vmaddr - W.write<uint64_t>(VMSize); // vmsize - W.write<uint64_t>(SectionDataStartOffset); // file offset - W.write<uint64_t>(SectionDataSize); // file size - } else { - W.write<uint32_t>(VMAddr); // vmaddr - W.write<uint32_t>(VMSize); // vmsize - W.write<uint32_t>(SectionDataStartOffset); // file offset - W.write<uint32_t>(SectionDataSize); // file size - } - // maxprot - W.write<uint32_t>(MaxProt); - // initprot - W.write<uint32_t>(InitProt); - W.write<uint32_t>(NumSections); - W.write<uint32_t>(0); // flags - - assert(W.OS.tell() - Start == SegmentLoadCommandSize); -} - -void MachObjectWriter::writeSection(const MCAsmLayout &Layout, - const MCSection &Sec, uint64_t VMAddr, - uint64_t FileOffset, unsigned Flags, - uint64_t RelocationsStart, - unsigned NumRelocations) { - uint64_t SectionSize = Layout.getSectionAddressSize(&Sec); - const MCSectionMachO &Section = cast<MCSectionMachO>(Sec); - - // The offset is unused for virtual sections. - if (Section.isVirtualSection()) { - assert(Layout.getSectionFileSize(&Sec) == 0 && "Invalid file size!"); - FileOffset = 0; - } - - // struct section (68 bytes) or - // struct section_64 (80 bytes) - - uint64_t Start = W.OS.tell(); - (void) Start; - - writeWithPadding(Section.getSectionName(), 16); - writeWithPadding(Section.getSegmentName(), 16); - if (is64Bit()) { - W.write<uint64_t>(VMAddr); // address - W.write<uint64_t>(SectionSize); // size - } else { - W.write<uint32_t>(VMAddr); // address - W.write<uint32_t>(SectionSize); // size - } - W.write<uint32_t>(FileOffset); - - assert(isPowerOf2_32(Section.getAlignment()) && "Invalid alignment!"); - W.write<uint32_t>(Log2_32(Section.getAlignment())); - W.write<uint32_t>(NumRelocations ? RelocationsStart : 0); - W.write<uint32_t>(NumRelocations); - W.write<uint32_t>(Flags); - W.write<uint32_t>(IndirectSymBase.lookup(&Sec)); // reserved1 - W.write<uint32_t>(Section.getStubSize()); // reserved2 - if (is64Bit()) - W.write<uint32_t>(0); // reserved3 - - assert(W.OS.tell() - Start == - (is64Bit() ? sizeof(MachO::section_64) : sizeof(MachO::section))); -} - -void MachObjectWriter::writeSymtabLoadCommand(uint32_t SymbolOffset, - uint32_t NumSymbols, - uint32_t StringTableOffset, - uint32_t StringTableSize) { - // struct symtab_command (24 bytes) - - uint64_t Start = W.OS.tell(); - (void) Start; - - W.write<uint32_t>(MachO::LC_SYMTAB); - W.write<uint32_t>(sizeof(MachO::symtab_command)); - W.write<uint32_t>(SymbolOffset); - W.write<uint32_t>(NumSymbols); - W.write<uint32_t>(StringTableOffset); - W.write<uint32_t>(StringTableSize); - - assert(W.OS.tell() - Start == sizeof(MachO::symtab_command)); -} - -void MachObjectWriter::writeDysymtabLoadCommand(uint32_t FirstLocalSymbol, - uint32_t NumLocalSymbols, - uint32_t FirstExternalSymbol, - uint32_t NumExternalSymbols, - uint32_t FirstUndefinedSymbol, - uint32_t NumUndefinedSymbols, - uint32_t IndirectSymbolOffset, - uint32_t NumIndirectSymbols) { - // struct dysymtab_command (80 bytes) - - uint64_t Start = W.OS.tell(); - (void) Start; - - W.write<uint32_t>(MachO::LC_DYSYMTAB); - W.write<uint32_t>(sizeof(MachO::dysymtab_command)); - W.write<uint32_t>(FirstLocalSymbol); - W.write<uint32_t>(NumLocalSymbols); - W.write<uint32_t>(FirstExternalSymbol); - W.write<uint32_t>(NumExternalSymbols); - W.write<uint32_t>(FirstUndefinedSymbol); - W.write<uint32_t>(NumUndefinedSymbols); - W.write<uint32_t>(0); // tocoff - W.write<uint32_t>(0); // ntoc - W.write<uint32_t>(0); // modtaboff - W.write<uint32_t>(0); // nmodtab - W.write<uint32_t>(0); // extrefsymoff - W.write<uint32_t>(0); // nextrefsyms - W.write<uint32_t>(IndirectSymbolOffset); - W.write<uint32_t>(NumIndirectSymbols); - W.write<uint32_t>(0); // extreloff - W.write<uint32_t>(0); // nextrel - W.write<uint32_t>(0); // locreloff - W.write<uint32_t>(0); // nlocrel - - assert(W.OS.tell() - Start == sizeof(MachO::dysymtab_command)); -} - -MachObjectWriter::MachSymbolData * -MachObjectWriter::findSymbolData(const MCSymbol &Sym) { - for (auto *SymbolData : - {&LocalSymbolData, &ExternalSymbolData, &UndefinedSymbolData}) - for (MachSymbolData &Entry : *SymbolData) - if (Entry.Symbol == &Sym) - return &Entry; - - return nullptr; -} - -const MCSymbol &MachObjectWriter::findAliasedSymbol(const MCSymbol &Sym) const { - const MCSymbol *S = &Sym; - while (S->isVariable()) { - const MCExpr *Value = S->getVariableValue(); - const auto *Ref = dyn_cast<MCSymbolRefExpr>(Value); - if (!Ref) - return *S; - S = &Ref->getSymbol(); - } - return *S; -} - -void MachObjectWriter::writeNlist(MachSymbolData &MSD, - const MCAsmLayout &Layout) { - const MCSymbol *Symbol = MSD.Symbol; - const MCSymbol &Data = *Symbol; - const MCSymbol *AliasedSymbol = &findAliasedSymbol(*Symbol); - uint8_t SectionIndex = MSD.SectionIndex; - uint8_t Type = 0; - uint64_t Address = 0; - bool IsAlias = Symbol != AliasedSymbol; - - const MCSymbol &OrigSymbol = *Symbol; - MachSymbolData *AliaseeInfo; - if (IsAlias) { - AliaseeInfo = findSymbolData(*AliasedSymbol); - if (AliaseeInfo) - SectionIndex = AliaseeInfo->SectionIndex; - Symbol = AliasedSymbol; - // FIXME: Should this update Data as well? - } - - // Set the N_TYPE bits. See <mach-o/nlist.h>. - // - // FIXME: Are the prebound or indirect fields possible here? - if (IsAlias && Symbol->isUndefined()) - Type = MachO::N_INDR; - else if (Symbol->isUndefined()) - Type = MachO::N_UNDF; - else if (Symbol->isAbsolute()) - Type = MachO::N_ABS; - else - Type = MachO::N_SECT; - - // FIXME: Set STAB bits. - - if (Data.isPrivateExtern()) - Type |= MachO::N_PEXT; - - // Set external bit. - if (Data.isExternal() || (!IsAlias && Symbol->isUndefined())) - Type |= MachO::N_EXT; - - // Compute the symbol address. - if (IsAlias && Symbol->isUndefined()) - Address = AliaseeInfo->StringIndex; - else if (Symbol->isDefined()) - Address = getSymbolAddress(OrigSymbol, Layout); - else if (Symbol->isCommon()) { - // Common symbols are encoded with the size in the address - // field, and their alignment in the flags. - Address = Symbol->getCommonSize(); - } - - // struct nlist (12 bytes) - - W.write<uint32_t>(MSD.StringIndex); - W.OS << char(Type); - W.OS << char(SectionIndex); - - // The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc' - // value. - bool EncodeAsAltEntry = - IsAlias && cast<MCSymbolMachO>(OrigSymbol).isAltEntry(); - W.write<uint16_t>(cast<MCSymbolMachO>(Symbol)->getEncodedFlags(EncodeAsAltEntry)); - if (is64Bit()) - W.write<uint64_t>(Address); - else - W.write<uint32_t>(Address); -} - -void MachObjectWriter::writeLinkeditLoadCommand(uint32_t Type, - uint32_t DataOffset, - uint32_t DataSize) { - uint64_t Start = W.OS.tell(); - (void) Start; - - W.write<uint32_t>(Type); - W.write<uint32_t>(sizeof(MachO::linkedit_data_command)); - W.write<uint32_t>(DataOffset); - W.write<uint32_t>(DataSize); - - assert(W.OS.tell() - Start == sizeof(MachO::linkedit_data_command)); -} - -static unsigned ComputeLinkerOptionsLoadCommandSize( - const std::vector<std::string> &Options, bool is64Bit) -{ - unsigned Size = sizeof(MachO::linker_option_command); - for (const std::string &Option : Options) - Size += Option.size() + 1; - return alignTo(Size, is64Bit ? 8 : 4); -} - -void MachObjectWriter::writeLinkerOptionsLoadCommand( - const std::vector<std::string> &Options) -{ - unsigned Size = ComputeLinkerOptionsLoadCommandSize(Options, is64Bit()); - uint64_t Start = W.OS.tell(); - (void) Start; - - W.write<uint32_t>(MachO::LC_LINKER_OPTION); - W.write<uint32_t>(Size); - W.write<uint32_t>(Options.size()); - uint64_t BytesWritten = sizeof(MachO::linker_option_command); - for (const std::string &Option : Options) { - // Write each string, including the null byte. - W.OS << Option << '\0'; - BytesWritten += Option.size() + 1; - } - - // Pad to a multiple of the pointer size. - W.OS.write_zeros(OffsetToAlignment(BytesWritten, is64Bit() ? 8 : 4)); - - assert(W.OS.tell() - Start == Size); -} - -static bool isFixupTargetValid(const MCValue &Target) { - // Target is (LHS - RHS + cst). - // We don't support the form where LHS is null: -RHS + cst - if (!Target.getSymA() && Target.getSymB()) - return false; - return true; -} - -void MachObjectWriter::recordRelocation(MCAssembler &Asm, - const MCAsmLayout &Layout, - const MCFragment *Fragment, - const MCFixup &Fixup, MCValue Target, - uint64_t &FixedValue) { - if (!isFixupTargetValid(Target)) { - Asm.getContext().reportError(Fixup.getLoc(), - "unsupported relocation expression"); - return; - } - - TargetObjectWriter->recordRelocation(this, Asm, Layout, Fragment, Fixup, - Target, FixedValue); -} - -void MachObjectWriter::bindIndirectSymbols(MCAssembler &Asm) { - // This is the point where 'as' creates actual symbols for indirect symbols - // (in the following two passes). It would be easier for us to do this sooner - // when we see the attribute, but that makes getting the order in the symbol - // table much more complicated than it is worth. - // - // FIXME: Revisit this when the dust settles. - - // Report errors for use of .indirect_symbol not in a symbol pointer section - // or stub section. - for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(), - ie = Asm.indirect_symbol_end(); it != ie; ++it) { - const MCSectionMachO &Section = cast<MCSectionMachO>(*it->Section); - - if (Section.getType() != MachO::S_NON_LAZY_SYMBOL_POINTERS && - Section.getType() != MachO::S_LAZY_SYMBOL_POINTERS && - Section.getType() != MachO::S_THREAD_LOCAL_VARIABLE_POINTERS && - Section.getType() != MachO::S_SYMBOL_STUBS) { - MCSymbol &Symbol = *it->Symbol; - report_fatal_error("indirect symbol '" + Symbol.getName() + - "' not in a symbol pointer or stub section"); - } - } - - // Bind non-lazy symbol pointers first. - unsigned IndirectIndex = 0; - for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(), - ie = Asm.indirect_symbol_end(); it != ie; ++it, ++IndirectIndex) { - const MCSectionMachO &Section = cast<MCSectionMachO>(*it->Section); - - if (Section.getType() != MachO::S_NON_LAZY_SYMBOL_POINTERS && - Section.getType() != MachO::S_THREAD_LOCAL_VARIABLE_POINTERS) - continue; - - // Initialize the section indirect symbol base, if necessary. - IndirectSymBase.insert(std::make_pair(it->Section, IndirectIndex)); - - Asm.registerSymbol(*it->Symbol); - } - - // Then lazy symbol pointers and symbol stubs. - IndirectIndex = 0; - for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(), - ie = Asm.indirect_symbol_end(); it != ie; ++it, ++IndirectIndex) { - const MCSectionMachO &Section = cast<MCSectionMachO>(*it->Section); - - if (Section.getType() != MachO::S_LAZY_SYMBOL_POINTERS && - Section.getType() != MachO::S_SYMBOL_STUBS) - continue; - - // Initialize the section indirect symbol base, if necessary. - IndirectSymBase.insert(std::make_pair(it->Section, IndirectIndex)); - - // Set the symbol type to undefined lazy, but only on construction. - // - // FIXME: Do not hardcode. - bool Created; - Asm.registerSymbol(*it->Symbol, &Created); - if (Created) - cast<MCSymbolMachO>(it->Symbol)->setReferenceTypeUndefinedLazy(true); - } -} - -/// computeSymbolTable - Compute the symbol table data -void MachObjectWriter::computeSymbolTable( - MCAssembler &Asm, std::vector<MachSymbolData> &LocalSymbolData, - std::vector<MachSymbolData> &ExternalSymbolData, - std::vector<MachSymbolData> &UndefinedSymbolData) { - // Build section lookup table. - DenseMap<const MCSection*, uint8_t> SectionIndexMap; - unsigned Index = 1; - for (MCAssembler::iterator it = Asm.begin(), - ie = Asm.end(); it != ie; ++it, ++Index) - SectionIndexMap[&*it] = Index; - assert(Index <= 256 && "Too many sections!"); - - // Build the string table. - for (const MCSymbol &Symbol : Asm.symbols()) { - if (!Asm.isSymbolLinkerVisible(Symbol)) - continue; - - StringTable.add(Symbol.getName()); - } - StringTable.finalize(); - - // Build the symbol arrays but only for non-local symbols. - // - // The particular order that we collect and then sort the symbols is chosen to - // match 'as'. Even though it doesn't matter for correctness, this is - // important for letting us diff .o files. - for (const MCSymbol &Symbol : Asm.symbols()) { - // Ignore non-linker visible symbols. - if (!Asm.isSymbolLinkerVisible(Symbol)) - continue; - - if (!Symbol.isExternal() && !Symbol.isUndefined()) - continue; - - MachSymbolData MSD; - MSD.Symbol = &Symbol; - MSD.StringIndex = StringTable.getOffset(Symbol.getName()); - - if (Symbol.isUndefined()) { - MSD.SectionIndex = 0; - UndefinedSymbolData.push_back(MSD); - } else if (Symbol.isAbsolute()) { - MSD.SectionIndex = 0; - ExternalSymbolData.push_back(MSD); - } else { - MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection()); - assert(MSD.SectionIndex && "Invalid section index!"); - ExternalSymbolData.push_back(MSD); - } - } - - // Now add the data for local symbols. - for (const MCSymbol &Symbol : Asm.symbols()) { - // Ignore non-linker visible symbols. - if (!Asm.isSymbolLinkerVisible(Symbol)) - continue; - - if (Symbol.isExternal() || Symbol.isUndefined()) - continue; - - MachSymbolData MSD; - MSD.Symbol = &Symbol; - MSD.StringIndex = StringTable.getOffset(Symbol.getName()); - - if (Symbol.isAbsolute()) { - MSD.SectionIndex = 0; - LocalSymbolData.push_back(MSD); - } else { - MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection()); - assert(MSD.SectionIndex && "Invalid section index!"); - LocalSymbolData.push_back(MSD); - } - } - - // External and undefined symbols are required to be in lexicographic order. - llvm::sort(ExternalSymbolData); - llvm::sort(UndefinedSymbolData); - - // Set the symbol indices. - Index = 0; - for (auto *SymbolData : - {&LocalSymbolData, &ExternalSymbolData, &UndefinedSymbolData}) - for (MachSymbolData &Entry : *SymbolData) - Entry.Symbol->setIndex(Index++); - - for (const MCSection &Section : Asm) { - for (RelAndSymbol &Rel : Relocations[&Section]) { - if (!Rel.Sym) - continue; - - // Set the Index and the IsExtern bit. - unsigned Index = Rel.Sym->getIndex(); - assert(isInt<24>(Index)); - if (W.Endian == support::little) - Rel.MRE.r_word1 = (Rel.MRE.r_word1 & (~0U << 24)) | Index | (1 << 27); - else - Rel.MRE.r_word1 = (Rel.MRE.r_word1 & 0xff) | Index << 8 | (1 << 4); - } - } -} - -void MachObjectWriter::computeSectionAddresses(const MCAssembler &Asm, - const MCAsmLayout &Layout) { - uint64_t StartAddress = 0; - for (const MCSection *Sec : Layout.getSectionOrder()) { - StartAddress = alignTo(StartAddress, Sec->getAlignment()); - SectionAddress[Sec] = StartAddress; - StartAddress += Layout.getSectionAddressSize(Sec); - - // Explicitly pad the section to match the alignment requirements of the - // following one. This is for 'gas' compatibility, it shouldn't - /// strictly be necessary. - StartAddress += getPaddingSize(Sec, Layout); - } -} - -void MachObjectWriter::executePostLayoutBinding(MCAssembler &Asm, - const MCAsmLayout &Layout) { - computeSectionAddresses(Asm, Layout); - - // Create symbol data for any indirect symbols. - bindIndirectSymbols(Asm); -} - -bool MachObjectWriter::isSymbolRefDifferenceFullyResolvedImpl( - const MCAssembler &Asm, const MCSymbol &A, const MCSymbol &B, - bool InSet) const { - // FIXME: We don't handle things like - // foo = . - // creating atoms. - if (A.isVariable() || B.isVariable()) - return false; - return MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(Asm, A, B, - InSet); -} - -bool MachObjectWriter::isSymbolRefDifferenceFullyResolvedImpl( - const MCAssembler &Asm, const MCSymbol &SymA, const MCFragment &FB, - bool InSet, bool IsPCRel) const { - if (InSet) - return true; - - // The effective address is - // addr(atom(A)) + offset(A) - // - addr(atom(B)) - offset(B) - // and the offsets are not relocatable, so the fixup is fully resolved when - // addr(atom(A)) - addr(atom(B)) == 0. - const MCSymbol &SA = findAliasedSymbol(SymA); - const MCSection &SecA = SA.getSection(); - const MCSection &SecB = *FB.getParent(); - - if (IsPCRel) { - // The simple (Darwin, except on x86_64) way of dealing with this was to - // assume that any reference to a temporary symbol *must* be a temporary - // symbol in the same atom, unless the sections differ. Therefore, any PCrel - // relocation to a temporary symbol (in the same section) is fully - // resolved. This also works in conjunction with absolutized .set, which - // requires the compiler to use .set to absolutize the differences between - // symbols which the compiler knows to be assembly time constants, so we - // don't need to worry about considering symbol differences fully resolved. - // - // If the file isn't using sub-sections-via-symbols, we can make the - // same assumptions about any symbol that we normally make about - // assembler locals. - - bool hasReliableSymbolDifference = isX86_64(); - if (!hasReliableSymbolDifference) { - if (!SA.isInSection() || &SecA != &SecB || - (!SA.isTemporary() && FB.getAtom() != SA.getFragment()->getAtom() && - Asm.getSubsectionsViaSymbols())) - return false; - return true; - } - // For Darwin x86_64, there is one special case when the reference IsPCRel. - // If the fragment with the reference does not have a base symbol but meets - // the simple way of dealing with this, in that it is a temporary symbol in - // the same atom then it is assumed to be fully resolved. This is needed so - // a relocation entry is not created and so the static linker does not - // mess up the reference later. - else if(!FB.getAtom() && - SA.isTemporary() && SA.isInSection() && &SecA == &SecB){ - return true; - } - } - - // If they are not in the same section, we can't compute the diff. - if (&SecA != &SecB) - return false; - - const MCFragment *FA = SA.getFragment(); - - // Bail if the symbol has no fragment. - if (!FA) - return false; - - // If the atoms are the same, they are guaranteed to have the same address. - if (FA->getAtom() == FB.getAtom()) - return true; - - // Otherwise, we can't prove this is fully resolved. - return false; -} - -static MachO::LoadCommandType getLCFromMCVM(MCVersionMinType Type) { - switch (Type) { - case MCVM_OSXVersionMin: return MachO::LC_VERSION_MIN_MACOSX; - case MCVM_IOSVersionMin: return MachO::LC_VERSION_MIN_IPHONEOS; - case MCVM_TvOSVersionMin: return MachO::LC_VERSION_MIN_TVOS; - case MCVM_WatchOSVersionMin: return MachO::LC_VERSION_MIN_WATCHOS; - } - llvm_unreachable("Invalid mc version min type"); -} - -uint64_t MachObjectWriter::writeObject(MCAssembler &Asm, - const MCAsmLayout &Layout) { - uint64_t StartOffset = W.OS.tell(); - - // Compute symbol table information and bind symbol indices. - computeSymbolTable(Asm, LocalSymbolData, ExternalSymbolData, - UndefinedSymbolData); - - unsigned NumSections = Asm.size(); - const MCAssembler::VersionInfoType &VersionInfo = - Layout.getAssembler().getVersionInfo(); - - // The section data starts after the header, the segment load command (and - // section headers) and the symbol table. - unsigned NumLoadCommands = 1; - uint64_t LoadCommandsSize = is64Bit() ? - sizeof(MachO::segment_command_64) + NumSections * sizeof(MachO::section_64): - sizeof(MachO::segment_command) + NumSections * sizeof(MachO::section); - - // Add the deployment target version info load command size, if used. - if (VersionInfo.Major != 0) { - ++NumLoadCommands; - if (VersionInfo.EmitBuildVersion) - LoadCommandsSize += sizeof(MachO::build_version_command); - else - LoadCommandsSize += sizeof(MachO::version_min_command); - } - - // Add the data-in-code load command size, if used. - unsigned NumDataRegions = Asm.getDataRegions().size(); - if (NumDataRegions) { - ++NumLoadCommands; - LoadCommandsSize += sizeof(MachO::linkedit_data_command); - } - - // Add the loh load command size, if used. - uint64_t LOHRawSize = Asm.getLOHContainer().getEmitSize(*this, Layout); - uint64_t LOHSize = alignTo(LOHRawSize, is64Bit() ? 8 : 4); - if (LOHSize) { - ++NumLoadCommands; - LoadCommandsSize += sizeof(MachO::linkedit_data_command); - } - - // Add the symbol table load command sizes, if used. - unsigned NumSymbols = LocalSymbolData.size() + ExternalSymbolData.size() + - UndefinedSymbolData.size(); - if (NumSymbols) { - NumLoadCommands += 2; - LoadCommandsSize += (sizeof(MachO::symtab_command) + - sizeof(MachO::dysymtab_command)); - } - - // Add the linker option load commands sizes. - for (const auto &Option : Asm.getLinkerOptions()) { - ++NumLoadCommands; - LoadCommandsSize += ComputeLinkerOptionsLoadCommandSize(Option, is64Bit()); - } - - // Compute the total size of the section data, as well as its file size and vm - // size. - uint64_t SectionDataStart = (is64Bit() ? sizeof(MachO::mach_header_64) : - sizeof(MachO::mach_header)) + LoadCommandsSize; - uint64_t SectionDataSize = 0; - uint64_t SectionDataFileSize = 0; - uint64_t VMSize = 0; - for (const MCSection &Sec : Asm) { - uint64_t Address = getSectionAddress(&Sec); - uint64_t Size = Layout.getSectionAddressSize(&Sec); - uint64_t FileSize = Layout.getSectionFileSize(&Sec); - FileSize += getPaddingSize(&Sec, Layout); - - VMSize = std::max(VMSize, Address + Size); - - if (Sec.isVirtualSection()) - continue; - - SectionDataSize = std::max(SectionDataSize, Address + Size); - SectionDataFileSize = std::max(SectionDataFileSize, Address + FileSize); - } - - // The section data is padded to 4 bytes. - // - // FIXME: Is this machine dependent? - unsigned SectionDataPadding = OffsetToAlignment(SectionDataFileSize, 4); - SectionDataFileSize += SectionDataPadding; - - // Write the prolog, starting with the header and load command... - writeHeader(MachO::MH_OBJECT, NumLoadCommands, LoadCommandsSize, - Asm.getSubsectionsViaSymbols()); - uint32_t Prot = - MachO::VM_PROT_READ | MachO::VM_PROT_WRITE | MachO::VM_PROT_EXECUTE; - writeSegmentLoadCommand("", NumSections, 0, VMSize, SectionDataStart, - SectionDataSize, Prot, Prot); - - // ... and then the section headers. - uint64_t RelocTableEnd = SectionDataStart + SectionDataFileSize; - for (const MCSection &Section : Asm) { - const auto &Sec = cast<MCSectionMachO>(Section); - std::vector<RelAndSymbol> &Relocs = Relocations[&Sec]; - unsigned NumRelocs = Relocs.size(); - uint64_t SectionStart = SectionDataStart + getSectionAddress(&Sec); - unsigned Flags = Sec.getTypeAndAttributes(); - if (Sec.hasInstructions()) - Flags |= MachO::S_ATTR_SOME_INSTRUCTIONS; - writeSection(Layout, Sec, getSectionAddress(&Sec), SectionStart, Flags, - RelocTableEnd, NumRelocs); - RelocTableEnd += NumRelocs * sizeof(MachO::any_relocation_info); - } - - // Write out the deployment target information, if it's available. - if (VersionInfo.Major != 0) { - auto EncodeVersion = [](VersionTuple V) -> uint32_t { - assert(!V.empty() && "empty version"); - unsigned Update = V.getSubminor() ? *V.getSubminor() : 0; - unsigned Minor = V.getMinor() ? *V.getMinor() : 0; - assert(Update < 256 && "unencodable update target version"); - assert(Minor < 256 && "unencodable minor target version"); - assert(V.getMajor() < 65536 && "unencodable major target version"); - return Update | (Minor << 8) | (V.getMajor() << 16); - }; - uint32_t EncodedVersion = EncodeVersion( - VersionTuple(VersionInfo.Major, VersionInfo.Minor, VersionInfo.Update)); - uint32_t SDKVersion = !VersionInfo.SDKVersion.empty() - ? EncodeVersion(VersionInfo.SDKVersion) - : 0; - if (VersionInfo.EmitBuildVersion) { - // FIXME: Currently empty tools. Add clang version in the future. - W.write<uint32_t>(MachO::LC_BUILD_VERSION); - W.write<uint32_t>(sizeof(MachO::build_version_command)); - W.write<uint32_t>(VersionInfo.TypeOrPlatform.Platform); - W.write<uint32_t>(EncodedVersion); - W.write<uint32_t>(SDKVersion); - W.write<uint32_t>(0); // Empty tools list. - } else { - MachO::LoadCommandType LCType - = getLCFromMCVM(VersionInfo.TypeOrPlatform.Type); - W.write<uint32_t>(LCType); - W.write<uint32_t>(sizeof(MachO::version_min_command)); - W.write<uint32_t>(EncodedVersion); - W.write<uint32_t>(SDKVersion); - } - } - - // Write the data-in-code load command, if used. - uint64_t DataInCodeTableEnd = RelocTableEnd + NumDataRegions * 8; - if (NumDataRegions) { - uint64_t DataRegionsOffset = RelocTableEnd; - uint64_t DataRegionsSize = NumDataRegions * 8; - writeLinkeditLoadCommand(MachO::LC_DATA_IN_CODE, DataRegionsOffset, - DataRegionsSize); - } - - // Write the loh load command, if used. - uint64_t LOHTableEnd = DataInCodeTableEnd + LOHSize; - if (LOHSize) - writeLinkeditLoadCommand(MachO::LC_LINKER_OPTIMIZATION_HINT, - DataInCodeTableEnd, LOHSize); - - // Write the symbol table load command, if used. - if (NumSymbols) { - unsigned FirstLocalSymbol = 0; - unsigned NumLocalSymbols = LocalSymbolData.size(); - unsigned FirstExternalSymbol = FirstLocalSymbol + NumLocalSymbols; - unsigned NumExternalSymbols = ExternalSymbolData.size(); - unsigned FirstUndefinedSymbol = FirstExternalSymbol + NumExternalSymbols; - unsigned NumUndefinedSymbols = UndefinedSymbolData.size(); - unsigned NumIndirectSymbols = Asm.indirect_symbol_size(); - unsigned NumSymTabSymbols = - NumLocalSymbols + NumExternalSymbols + NumUndefinedSymbols; - uint64_t IndirectSymbolSize = NumIndirectSymbols * 4; - uint64_t IndirectSymbolOffset = 0; - - // If used, the indirect symbols are written after the section data. - if (NumIndirectSymbols) - IndirectSymbolOffset = LOHTableEnd; - - // The symbol table is written after the indirect symbol data. - uint64_t SymbolTableOffset = LOHTableEnd + IndirectSymbolSize; - - // The string table is written after symbol table. - uint64_t StringTableOffset = - SymbolTableOffset + NumSymTabSymbols * (is64Bit() ? - sizeof(MachO::nlist_64) : - sizeof(MachO::nlist)); - writeSymtabLoadCommand(SymbolTableOffset, NumSymTabSymbols, - StringTableOffset, StringTable.getSize()); - - writeDysymtabLoadCommand(FirstLocalSymbol, NumLocalSymbols, - FirstExternalSymbol, NumExternalSymbols, - FirstUndefinedSymbol, NumUndefinedSymbols, - IndirectSymbolOffset, NumIndirectSymbols); - } - - // Write the linker options load commands. - for (const auto &Option : Asm.getLinkerOptions()) - writeLinkerOptionsLoadCommand(Option); - - // Write the actual section data. - for (const MCSection &Sec : Asm) { - Asm.writeSectionData(W.OS, &Sec, Layout); - - uint64_t Pad = getPaddingSize(&Sec, Layout); - W.OS.write_zeros(Pad); - } - - // Write the extra padding. - W.OS.write_zeros(SectionDataPadding); - - // Write the relocation entries. - for (const MCSection &Sec : Asm) { - // Write the section relocation entries, in reverse order to match 'as' - // (approximately, the exact algorithm is more complicated than this). - std::vector<RelAndSymbol> &Relocs = Relocations[&Sec]; - for (const RelAndSymbol &Rel : make_range(Relocs.rbegin(), Relocs.rend())) { - W.write<uint32_t>(Rel.MRE.r_word0); - W.write<uint32_t>(Rel.MRE.r_word1); - } - } - - // Write out the data-in-code region payload, if there is one. - for (MCAssembler::const_data_region_iterator - it = Asm.data_region_begin(), ie = Asm.data_region_end(); - it != ie; ++it) { - const DataRegionData *Data = &(*it); - uint64_t Start = getSymbolAddress(*Data->Start, Layout); - uint64_t End; - if (Data->End) - End = getSymbolAddress(*Data->End, Layout); - else - report_fatal_error("Data region not terminated"); - - LLVM_DEBUG(dbgs() << "data in code region-- kind: " << Data->Kind - << " start: " << Start << "(" << Data->Start->getName() - << ")" - << " end: " << End << "(" << Data->End->getName() << ")" - << " size: " << End - Start << "\n"); - W.write<uint32_t>(Start); - W.write<uint16_t>(End - Start); - W.write<uint16_t>(Data->Kind); - } - - // Write out the loh commands, if there is one. - if (LOHSize) { -#ifndef NDEBUG - unsigned Start = W.OS.tell(); -#endif - Asm.getLOHContainer().emit(*this, Layout); - // Pad to a multiple of the pointer size. - W.OS.write_zeros(OffsetToAlignment(LOHRawSize, is64Bit() ? 8 : 4)); - assert(W.OS.tell() - Start == LOHSize); - } - - // Write the symbol table data, if used. - if (NumSymbols) { - // Write the indirect symbol entries. - for (MCAssembler::const_indirect_symbol_iterator - it = Asm.indirect_symbol_begin(), - ie = Asm.indirect_symbol_end(); it != ie; ++it) { - // Indirect symbols in the non-lazy symbol pointer section have some - // special handling. - const MCSectionMachO &Section = - static_cast<const MCSectionMachO &>(*it->Section); - if (Section.getType() == MachO::S_NON_LAZY_SYMBOL_POINTERS) { - // If this symbol is defined and internal, mark it as such. - if (it->Symbol->isDefined() && !it->Symbol->isExternal()) { - uint32_t Flags = MachO::INDIRECT_SYMBOL_LOCAL; - if (it->Symbol->isAbsolute()) - Flags |= MachO::INDIRECT_SYMBOL_ABS; - W.write<uint32_t>(Flags); - continue; - } - } - - W.write<uint32_t>(it->Symbol->getIndex()); - } - - // FIXME: Check that offsets match computed ones. - - // Write the symbol table entries. - for (auto *SymbolData : - {&LocalSymbolData, &ExternalSymbolData, &UndefinedSymbolData}) - for (MachSymbolData &Entry : *SymbolData) - writeNlist(Entry, Layout); - - // Write the string table. - StringTable.write(W.OS); - } - - return W.OS.tell() - StartOffset; -} - -std::unique_ptr<MCObjectWriter> -llvm::createMachObjectWriter(std::unique_ptr<MCMachObjectTargetWriter> MOTW, - raw_pwrite_stream &OS, bool IsLittleEndian) { - return llvm::make_unique<MachObjectWriter>(std::move(MOTW), OS, - IsLittleEndian); -} |