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Diffstat (limited to 'contrib/llvm/lib/MC/MCMachOStreamer.cpp')
| -rw-r--r-- | contrib/llvm/lib/MC/MCMachOStreamer.cpp | 678 |
1 files changed, 678 insertions, 0 deletions
diff --git a/contrib/llvm/lib/MC/MCMachOStreamer.cpp b/contrib/llvm/lib/MC/MCMachOStreamer.cpp new file mode 100644 index 0000000..671874d --- /dev/null +++ b/contrib/llvm/lib/MC/MCMachOStreamer.cpp @@ -0,0 +1,678 @@ +//===- lib/MC/MCMachOStreamer.cpp - Mach-O Object Output ------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "llvm/MC/MCStreamer.h" + +#include "llvm/MC/MCAssembler.h" +#include "llvm/MC/MCContext.h" +#include "llvm/MC/MCCodeEmitter.h" +#include "llvm/MC/MCExpr.h" +#include "llvm/MC/MCInst.h" +#include "llvm/MC/MCObjectStreamer.h" +#include "llvm/MC/MCSection.h" +#include "llvm/MC/MCSymbol.h" +#include "llvm/MC/MCMachOSymbolFlags.h" +#include "llvm/MC/MCSectionMachO.h" +#include "llvm/MC/MCDwarf.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetAsmBackend.h" + +using namespace llvm; + +namespace { + +class MCMachOStreamer : public MCObjectStreamer { +private: + void EmitInstToFragment(const MCInst &Inst); + void EmitInstToData(const MCInst &Inst); + // FIXME: These will likely moved to a better place. + void MakeLineEntryForSection(const MCSection *Section); + const MCExpr * MakeStartMinusEndExpr(MCSymbol *Start, MCSymbol *End, + int IntVal); + void EmitDwarfFileTable(void); + +public: + MCMachOStreamer(MCContext &Context, TargetAsmBackend &TAB, + raw_ostream &OS, MCCodeEmitter *Emitter) + : MCObjectStreamer(Context, TAB, OS, Emitter) {} + + /// @name MCStreamer Interface + /// @{ + + virtual void EmitLabel(MCSymbol *Symbol); + virtual void EmitAssemblerFlag(MCAssemblerFlag Flag); + virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value); + virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute); + virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue); + virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, + unsigned ByteAlignment); + virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) { + assert(0 && "macho doesn't support this directive"); + } + virtual void EmitCOFFSymbolStorageClass(int StorageClass) { + assert(0 && "macho doesn't support this directive"); + } + virtual void EmitCOFFSymbolType(int Type) { + assert(0 && "macho doesn't support this directive"); + } + virtual void EndCOFFSymbolDef() { + assert(0 && "macho doesn't support this directive"); + } + virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) { + assert(0 && "macho doesn't support this directive"); + } + virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) { + assert(0 && "macho doesn't support this directive"); + } + virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0, + unsigned Size = 0, unsigned ByteAlignment = 0); + virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol, + uint64_t Size, unsigned ByteAlignment = 0); + virtual void EmitBytes(StringRef Data, unsigned AddrSpace); + virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace); + virtual void EmitGPRel32Value(const MCExpr *Value) { + assert(0 && "macho doesn't support this directive"); + } + virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0, + unsigned ValueSize = 1, + unsigned MaxBytesToEmit = 0); + virtual void EmitCodeAlignment(unsigned ByteAlignment, + unsigned MaxBytesToEmit = 0); + virtual void EmitValueToOffset(const MCExpr *Offset, + unsigned char Value = 0); + + virtual void EmitFileDirective(StringRef Filename) { + // FIXME: Just ignore the .file; it isn't important enough to fail the + // entire assembly. + + //report_fatal_error("unsupported directive: '.file'"); + } + virtual void EmitDwarfFileDirective(unsigned FileNo, StringRef Filename) { + // FIXME: Just ignore the .file; it isn't important enough to fail the + // entire assembly. + + //report_fatal_error("unsupported directive: '.file'"); + } + + virtual void EmitInstruction(const MCInst &Inst); + + virtual void Finish(); + + /// @} +}; + +} // end anonymous namespace. + +void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) { + // TODO: This is almost exactly the same as WinCOFFStreamer. Consider merging + // into MCObjectStreamer. + assert(Symbol->isUndefined() && "Cannot define a symbol twice!"); + assert(!Symbol->isVariable() && "Cannot emit a variable symbol!"); + assert(CurSection && "Cannot emit before setting section!"); + + Symbol->setSection(*CurSection); + + MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol); + + // We have to create a new fragment if this is an atom defining symbol, + // fragments cannot span atoms. + if (getAssembler().isSymbolLinkerVisible(SD.getSymbol())) + new MCDataFragment(getCurrentSectionData()); + + // FIXME: This is wasteful, we don't necessarily need to create a data + // fragment. Instead, we should mark the symbol as pointing into the data + // fragment if it exists, otherwise we should just queue the label and set its + // fragment pointer when we emit the next fragment. + MCDataFragment *F = getOrCreateDataFragment(); + assert(!SD.getFragment() && "Unexpected fragment on symbol data!"); + SD.setFragment(F); + SD.setOffset(F->getContents().size()); + + // This causes the reference type flag to be cleared. Darwin 'as' was "trying" + // to clear the weak reference and weak definition bits too, but the + // implementation was buggy. For now we just try to match 'as', for + // diffability. + // + // FIXME: Cleanup this code, these bits should be emitted based on semantic + // properties, not on the order of definition, etc. + SD.setFlags(SD.getFlags() & ~SF_ReferenceTypeMask); +} + +void MCMachOStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) { + switch (Flag) { + case MCAF_SubsectionsViaSymbols: + getAssembler().setSubsectionsViaSymbols(true); + return; + } + + assert(0 && "invalid assembler flag!"); +} + +void MCMachOStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) { + // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into + // MCObjectStreamer. + // FIXME: Lift context changes into super class. + getAssembler().getOrCreateSymbolData(*Symbol); + Symbol->setVariableValue(AddValueSymbols(Value)); +} + +void MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol, + MCSymbolAttr Attribute) { + // Indirect symbols are handled differently, to match how 'as' handles + // them. This makes writing matching .o files easier. + if (Attribute == MCSA_IndirectSymbol) { + // Note that we intentionally cannot use the symbol data here; this is + // important for matching the string table that 'as' generates. + IndirectSymbolData ISD; + ISD.Symbol = Symbol; + ISD.SectionData = getCurrentSectionData(); + getAssembler().getIndirectSymbols().push_back(ISD); + return; + } + + // Adding a symbol attribute always introduces the symbol, note that an + // important side effect of calling getOrCreateSymbolData here is to register + // the symbol with the assembler. + MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol); + + // The implementation of symbol attributes is designed to match 'as', but it + // leaves much to desired. It doesn't really make sense to arbitrarily add and + // remove flags, but 'as' allows this (in particular, see .desc). + // + // In the future it might be worth trying to make these operations more well + // defined. + switch (Attribute) { + case MCSA_Invalid: + case MCSA_ELF_TypeFunction: + case MCSA_ELF_TypeIndFunction: + case MCSA_ELF_TypeObject: + case MCSA_ELF_TypeTLS: + case MCSA_ELF_TypeCommon: + case MCSA_ELF_TypeNoType: + case MCSA_IndirectSymbol: + case MCSA_Hidden: + case MCSA_Internal: + case MCSA_Protected: + case MCSA_Weak: + case MCSA_Local: + assert(0 && "Invalid symbol attribute for Mach-O!"); + break; + + case MCSA_Global: + SD.setExternal(true); + // This effectively clears the undefined lazy bit, in Darwin 'as', although + // it isn't very consistent because it implements this as part of symbol + // lookup. + // + // FIXME: Cleanup this code, these bits should be emitted based on semantic + // properties, not on the order of definition, etc. + SD.setFlags(SD.getFlags() & ~SF_ReferenceTypeUndefinedLazy); + break; + + case MCSA_LazyReference: + // FIXME: This requires -dynamic. + SD.setFlags(SD.getFlags() | SF_NoDeadStrip); + if (Symbol->isUndefined()) + SD.setFlags(SD.getFlags() | SF_ReferenceTypeUndefinedLazy); + break; + + // Since .reference sets the no dead strip bit, it is equivalent to + // .no_dead_strip in practice. + case MCSA_Reference: + case MCSA_NoDeadStrip: + SD.setFlags(SD.getFlags() | SF_NoDeadStrip); + break; + + case MCSA_PrivateExtern: + SD.setExternal(true); + SD.setPrivateExtern(true); + break; + + case MCSA_WeakReference: + // FIXME: This requires -dynamic. + if (Symbol->isUndefined()) + SD.setFlags(SD.getFlags() | SF_WeakReference); + break; + + case MCSA_WeakDefinition: + // FIXME: 'as' enforces that this is defined and global. The manual claims + // it has to be in a coalesced section, but this isn't enforced. + SD.setFlags(SD.getFlags() | SF_WeakDefinition); + break; + + case MCSA_WeakDefAutoPrivate: + SD.setFlags(SD.getFlags() | SF_WeakDefinition | SF_WeakReference); + break; + } +} + +void MCMachOStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) { + // Encode the 'desc' value into the lowest implementation defined bits. + assert(DescValue == (DescValue & SF_DescFlagsMask) && + "Invalid .desc value!"); + getAssembler().getOrCreateSymbolData(*Symbol).setFlags( + DescValue & SF_DescFlagsMask); +} + +void MCMachOStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, + unsigned ByteAlignment) { + // FIXME: Darwin 'as' does appear to allow redef of a .comm by itself. + assert(Symbol->isUndefined() && "Cannot define a symbol twice!"); + + MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol); + SD.setExternal(true); + SD.setCommon(Size, ByteAlignment); +} + +void MCMachOStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol, + unsigned Size, unsigned ByteAlignment) { + MCSectionData &SectData = getAssembler().getOrCreateSectionData(*Section); + + // The symbol may not be present, which only creates the section. + if (!Symbol) + return; + + // FIXME: Assert that this section has the zerofill type. + + assert(Symbol->isUndefined() && "Cannot define a symbol twice!"); + + MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol); + + // Emit an align fragment if necessary. + if (ByteAlignment != 1) + new MCAlignFragment(ByteAlignment, 0, 0, ByteAlignment, &SectData); + + MCFragment *F = new MCFillFragment(0, 0, Size, &SectData); + SD.setFragment(F); + + Symbol->setSection(*Section); + + // Update the maximum alignment on the zero fill section if necessary. + if (ByteAlignment > SectData.getAlignment()) + SectData.setAlignment(ByteAlignment); +} + +// This should always be called with the thread local bss section. Like the +// .zerofill directive this doesn't actually switch sections on us. +void MCMachOStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol, + uint64_t Size, unsigned ByteAlignment) { + EmitZerofill(Section, Symbol, Size, ByteAlignment); + return; +} + +void MCMachOStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) { + // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into + // MCObjectStreamer. + getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end()); +} + +void MCMachOStreamer::EmitValue(const MCExpr *Value, unsigned Size, + unsigned AddrSpace) { + // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into + // MCObjectStreamer. + MCDataFragment *DF = getOrCreateDataFragment(); + + // Avoid fixups when possible. + int64_t AbsValue; + if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue)) { + // FIXME: Endianness assumption. + for (unsigned i = 0; i != Size; ++i) + DF->getContents().push_back(uint8_t(AbsValue >> (i * 8))); + } else { + DF->addFixup(MCFixup::Create(DF->getContents().size(), + AddValueSymbols(Value), + MCFixup::getKindForSize(Size))); + DF->getContents().resize(DF->getContents().size() + Size, 0); + } +} + +void MCMachOStreamer::EmitValueToAlignment(unsigned ByteAlignment, + int64_t Value, unsigned ValueSize, + unsigned MaxBytesToEmit) { + // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into + // MCObjectStreamer. + if (MaxBytesToEmit == 0) + MaxBytesToEmit = ByteAlignment; + new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit, + getCurrentSectionData()); + + // Update the maximum alignment on the current section if necessary. + if (ByteAlignment > getCurrentSectionData()->getAlignment()) + getCurrentSectionData()->setAlignment(ByteAlignment); +} + +void MCMachOStreamer::EmitCodeAlignment(unsigned ByteAlignment, + unsigned MaxBytesToEmit) { + // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into + // MCObjectStreamer. + if (MaxBytesToEmit == 0) + MaxBytesToEmit = ByteAlignment; + MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit, + getCurrentSectionData()); + F->setEmitNops(true); + + // Update the maximum alignment on the current section if necessary. + if (ByteAlignment > getCurrentSectionData()->getAlignment()) + getCurrentSectionData()->setAlignment(ByteAlignment); +} + +void MCMachOStreamer::EmitValueToOffset(const MCExpr *Offset, + unsigned char Value) { + new MCOrgFragment(*Offset, Value, getCurrentSectionData()); +} + +void MCMachOStreamer::EmitInstToFragment(const MCInst &Inst) { + MCInstFragment *IF = new MCInstFragment(Inst, getCurrentSectionData()); + + // Add the fixups and data. + // + // FIXME: Revisit this design decision when relaxation is done, we may be + // able to get away with not storing any extra data in the MCInst. + SmallVector<MCFixup, 4> Fixups; + SmallString<256> Code; + raw_svector_ostream VecOS(Code); + getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups); + VecOS.flush(); + + IF->getCode() = Code; + IF->getFixups() = Fixups; +} + +void MCMachOStreamer::EmitInstToData(const MCInst &Inst) { + MCDataFragment *DF = getOrCreateDataFragment(); + + SmallVector<MCFixup, 4> Fixups; + SmallString<256> Code; + raw_svector_ostream VecOS(Code); + getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups); + VecOS.flush(); + + // Add the fixups and data. + for (unsigned i = 0, e = Fixups.size(); i != e; ++i) { + Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size()); + DF->addFixup(Fixups[i]); + } + DF->getContents().append(Code.begin(), Code.end()); +} + +void MCMachOStreamer::EmitInstruction(const MCInst &Inst) { + // Scan for values. + for (unsigned i = Inst.getNumOperands(); i--; ) + if (Inst.getOperand(i).isExpr()) + AddValueSymbols(Inst.getOperand(i).getExpr()); + + getCurrentSectionData()->setHasInstructions(true); + + // Now that a machine instruction has been assembled into this section, make + // a line entry for any .loc directive that has been seen. + MakeLineEntryForSection(getCurrentSection()); + + // If this instruction doesn't need relaxation, just emit it as data. + if (!getAssembler().getBackend().MayNeedRelaxation(Inst)) { + EmitInstToData(Inst); + return; + } + + // Otherwise, if we are relaxing everything, relax the instruction as much as + // possible and emit it as data. + if (getAssembler().getRelaxAll()) { + MCInst Relaxed; + getAssembler().getBackend().RelaxInstruction(Inst, Relaxed); + while (getAssembler().getBackend().MayNeedRelaxation(Relaxed)) + getAssembler().getBackend().RelaxInstruction(Relaxed, Relaxed); + EmitInstToData(Relaxed); + return; + } + + // Otherwise emit to a separate fragment. + EmitInstToFragment(Inst); +} + +// +// This is called when an instruction is assembled into the specified section +// and if there is information from the last .loc directive that has yet to have +// a line entry made for it is made. +// +void MCMachOStreamer::MakeLineEntryForSection(const MCSection *Section) { + if (!getContext().getDwarfLocSeen()) + return; + + // Create a symbol at in the current section for use in the line entry. + MCSymbol *LineSym = getContext().CreateTempSymbol(); + // Set the value of the symbol to use for the MCLineEntry. + EmitLabel(LineSym); + + // Get the current .loc info saved in the context. + const MCDwarfLoc &DwarfLoc = getContext().getCurrentDwarfLoc(); + + // Create a (local) line entry with the symbol and the current .loc info. + MCLineEntry LineEntry(LineSym, DwarfLoc); + + // clear DwarfLocSeen saying the current .loc info is now used. + getContext().clearDwarfLocSeen(); + + // Get the MCLineSection for this section, if one does not exist for this + // section create it. + DenseMap<const MCSection *, MCLineSection *> &MCLineSections = + getContext().getMCLineSections(); + MCLineSection *LineSection = MCLineSections[Section]; + if (!LineSection) { + // Create a new MCLineSection. This will be deleted after the dwarf line + // table is created using it by iterating through the MCLineSections + // DenseMap. + LineSection = new MCLineSection; + // Save a pointer to the new LineSection into the MCLineSections DenseMap. + MCLineSections[Section] = LineSection; + } + + // Add the line entry to this section's entries. + LineSection->addLineEntry(LineEntry); +} + +// +// This helper routine returns an expression of End - Start + IntVal for use +// by EmitDwarfFileTable() below. +// +const MCExpr * MCMachOStreamer::MakeStartMinusEndExpr(MCSymbol *Start, + MCSymbol *End, + int IntVal) { + MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None; + const MCExpr *Res = + MCSymbolRefExpr::Create(End, Variant, getContext()); + const MCExpr *RHS = + MCSymbolRefExpr::Create(Start, Variant, getContext()); + const MCExpr *Res1 = + MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS,getContext()); + const MCExpr *Res2 = + MCConstantExpr::Create(IntVal, getContext()); + const MCExpr *Res3 = + MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, getContext()); + return Res3; +} + +// +// This emits the Dwarf file (and eventually the line) table. +// +void MCMachOStreamer::EmitDwarfFileTable(void) { + // For now make sure we don't put out the Dwarf file table if no .file + // directives were seen. + const std::vector<MCDwarfFile *> &MCDwarfFiles = + getContext().getMCDwarfFiles(); + if (MCDwarfFiles.size() == 0) + return; + + // This is the Mach-O section, for ELF it is the .debug_line section. + SwitchSection(getContext().getMachOSection("__DWARF", "__debug_line", + MCSectionMachO::S_ATTR_DEBUG, + 0, SectionKind::getDataRelLocal())); + + // Create a symbol at the beginning of this section. + MCSymbol *LineStartSym = getContext().CreateTempSymbol(); + // Set the value of the symbol, as we are at the start of the section. + EmitLabel(LineStartSym); + + // Create a symbol for the end of the section (to be set when we get there). + MCSymbol *LineEndSym = getContext().CreateTempSymbol(); + + // The first 4 bytes is the total length of the information for this + // compilation unit (not including these 4 bytes for the length). + EmitValue(MakeStartMinusEndExpr(LineStartSym, LineEndSym, 4), 4, 0); + + // Next 2 bytes is the Version, which is Dwarf 2. + EmitIntValue(2, 2); + + // Create a symbol for the end of the prologue (to be set when we get there). + MCSymbol *ProEndSym = getContext().CreateTempSymbol(); // Lprologue_end + + // Length of the prologue, is the next 4 bytes. Which is the start of the + // section to the end of the prologue. Not including the 4 bytes for the + // total length, the 2 bytes for the version, and these 4 bytes for the + // length of the prologue. + EmitValue(MakeStartMinusEndExpr(LineStartSym, ProEndSym, (4 + 2 + 4)), 4, 0); + + // Parameters of the state machine, are next. + // Define the architecture-dependent minimum instruction length (in + // bytes). This value should be rather too small than too big. */ + // DWARF2_LINE_MIN_INSN_LENGTH + EmitIntValue(1, 1); + // Flag that indicates the initial value of the is_stmt_start flag. + // DWARF2_LINE_DEFAULT_IS_STMT + EmitIntValue(1, 1); + // Minimum line offset in a special line info. opcode. This value + // was chosen to give a reasonable range of values. */ + // DWARF2_LINE_BASE + EmitIntValue(uint64_t(-5), 1); + // Range of line offsets in a special line info. opcode. + // DWARF2_LINE_RANGE + EmitIntValue(14, 1); + // First special line opcode - leave room for the standard opcodes. + // DWARF2_LINE_OPCODE_BASE + EmitIntValue(13, 1); + + // Standard opcode lengths + EmitIntValue(0, 1); // length of DW_LNS_copy + EmitIntValue(1, 1); // length of DW_LNS_advance_pc + EmitIntValue(1, 1); // length of DW_LNS_advance_line + EmitIntValue(1, 1); // length of DW_LNS_set_file + EmitIntValue(1, 1); // length of DW_LNS_set_column + EmitIntValue(0, 1); // length of DW_LNS_negate_stmt + EmitIntValue(0, 1); // length of DW_LNS_set_basic_block + EmitIntValue(0, 1); // length of DW_LNS_const_add_pc + EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc + EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end + EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin + EmitIntValue(1, 1); // DW_LNS_set_isa + + // Put out the directory and file tables. + + // First the directory table. + const std::vector<StringRef> &MCDwarfDirs = + getContext().getMCDwarfDirs(); + for (unsigned i = 0; i < MCDwarfDirs.size(); i++) { + EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName + EmitBytes(StringRef("\0", 1), 0); // the null termination of the string + } + EmitIntValue(0, 1); // Terminate the directory list + + // Second the file table. + for (unsigned i = 1; i < MCDwarfFiles.size(); i++) { + EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName + EmitBytes(StringRef("\0", 1), 0); // the null termination of the string + // FIXME the Directory number should be a .uleb128 not a .byte + EmitIntValue(MCDwarfFiles[i]->getDirIndex(), 1); + EmitIntValue(0, 1); // last modification timestamp (always 0) + EmitIntValue(0, 1); // filesize (always 0) + } + EmitIntValue(0, 1); // Terminate the file list + + // This is the end of the prologue, so set the value of the symbol at the + // end of the prologue (that was used in a previous expression). + EmitLabel(ProEndSym); + + // TODO: This is the point where the line tables would be emitted. + + // Delete the MCLineSections that were created in + // MCMachOStreamer::MakeLineEntryForSection() and used to emit the line + // tables. + DenseMap<const MCSection *, MCLineSection *> &MCLineSections = + getContext().getMCLineSections(); + for (DenseMap<const MCSection *, MCLineSection *>::iterator it = + MCLineSections.begin(), ie = MCLineSections.end(); it != ie; ++it) { + delete it->second; + } + + // If there are no line tables emited then we emit: + // The following DW_LNE_set_address sequence to set the address to zero + // TODO test for 32-bit or 64-bit output + // This is the sequence for 32-bit code + EmitIntValue(0, 1); + EmitIntValue(5, 1); + EmitIntValue(2, 1); + EmitIntValue(0, 1); + EmitIntValue(0, 1); + EmitIntValue(0, 1); + EmitIntValue(0, 1); + + // Lastly emit the DW_LNE_end_sequence which consists of 3 bytes '00 01 01' + // (00 is the code for extended opcodes, followed by a ULEB128 length of the + // extended opcode (01), and the DW_LNE_end_sequence (01). + EmitIntValue(0, 1); // DW_LNS_extended_op + EmitIntValue(1, 1); // ULEB128 length of the extended opcode + EmitIntValue(1, 1); // DW_LNE_end_sequence + + // This is the end of the section, so set the value of the symbol at the end + // of this section (that was used in a previous expression). + EmitLabel(LineEndSym); +} + +void MCMachOStreamer::Finish() { + // Dump out the dwarf file and directory tables (soon to include line table) + EmitDwarfFileTable(); + + // We have to set the fragment atom associations so we can relax properly for + // Mach-O. + + // First, scan the symbol table to build a lookup table from fragments to + // defining symbols. + DenseMap<const MCFragment*, MCSymbolData*> DefiningSymbolMap; + for (MCAssembler::symbol_iterator it = getAssembler().symbol_begin(), + ie = getAssembler().symbol_end(); it != ie; ++it) { + if (getAssembler().isSymbolLinkerVisible(it->getSymbol()) && + it->getFragment()) { + // An atom defining symbol should never be internal to a fragment. + assert(it->getOffset() == 0 && "Invalid offset in atom defining symbol!"); + DefiningSymbolMap[it->getFragment()] = it; + } + } + + // Set the fragment atom associations by tracking the last seen atom defining + // symbol. + for (MCAssembler::iterator it = getAssembler().begin(), + ie = getAssembler().end(); it != ie; ++it) { + MCSymbolData *CurrentAtom = 0; + for (MCSectionData::iterator it2 = it->begin(), + ie2 = it->end(); it2 != ie2; ++it2) { + if (MCSymbolData *SD = DefiningSymbolMap.lookup(it2)) + CurrentAtom = SD; + it2->setAtom(CurrentAtom); + } + } + + this->MCObjectStreamer::Finish(); +} + +MCStreamer *llvm::createMachOStreamer(MCContext &Context, TargetAsmBackend &TAB, + raw_ostream &OS, MCCodeEmitter *CE, + bool RelaxAll) { + MCMachOStreamer *S = new MCMachOStreamer(Context, TAB, OS, CE); + if (RelaxAll) + S->getAssembler().setRelaxAll(true); + return S; +} |
