1 files changed, 383 insertions, 0 deletions
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
new file mode 100644
index 0000000..99a819f
--- /dev/null
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -0,0 +1,383 @@
+//===- 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/MCSection.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCValue.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+namespace {
+
+class MCMachOStreamer : public MCStreamer {
+  /// SymbolFlags - We store the value for the 'desc' symbol field in the lowest
+  /// 16 bits of the implementation defined flags.
+  enum SymbolFlags { // See <mach-o/nlist.h>.
+    SF_DescFlagsMask                        = 0xFFFF,
+
+    // Reference type flags.
+    SF_ReferenceTypeMask                    = 0x0007,
+    SF_ReferenceTypeUndefinedNonLazy        = 0x0000,
+    SF_ReferenceTypeUndefinedLazy           = 0x0001,
+    SF_ReferenceTypeDefined                 = 0x0002,
+    SF_ReferenceTypePrivateDefined          = 0x0003,
+    SF_ReferenceTypePrivateUndefinedNonLazy = 0x0004,
+    SF_ReferenceTypePrivateUndefinedLazy    = 0x0005,
+
+    // Other 'desc' flags.
+    SF_NoDeadStrip                          = 0x0020,
+    SF_WeakReference                        = 0x0040,
+    SF_WeakDefinition                       = 0x0080
+  };
+
+private:
+  MCAssembler Assembler;
+  MCCodeEmitter *Emitter;
+  MCSectionData *CurSectionData;
+  DenseMap<const MCSection*, MCSectionData*> SectionMap;
+  DenseMap<const MCSymbol*, MCSymbolData*> SymbolMap;
+
+private:
+  MCFragment *getCurrentFragment() const {
+    assert(CurSectionData && "No current section!");
+
+    if (!CurSectionData->empty())
+      return &CurSectionData->getFragmentList().back();
+
+    return 0;
+  }
+
+  MCSectionData &getSectionData(const MCSection &Section) {
+    MCSectionData *&Entry = SectionMap[&Section];
+
+    if (!Entry)
+      Entry = new MCSectionData(Section, &Assembler);
+
+    return *Entry;
+  }
+
+  MCSymbolData &getSymbolData(const MCSymbol &Symbol) {
+    MCSymbolData *&Entry = SymbolMap[&Symbol];
+
+    if (!Entry)
+      Entry = new MCSymbolData(Symbol, 0, 0, &Assembler);
+
+    return *Entry;
+  }
+
+public:
+  MCMachOStreamer(MCContext &Context, raw_ostream &_OS, MCCodeEmitter *_Emitter)
+    : MCStreamer(Context), Assembler(Context, _OS), Emitter(_Emitter),
+      CurSectionData(0) {}
+  ~MCMachOStreamer() {}
+
+  const MCExpr *AddValueSymbols(const MCExpr *Value) {
+    switch (Value->getKind()) {
+    case MCExpr::Target: assert(0 && "Can't handle target exprs yet!");
+    case MCExpr::Constant:
+      break;
+
+    case MCExpr::Binary: {
+      const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
+      AddValueSymbols(BE->getLHS());
+      AddValueSymbols(BE->getRHS());
+      break;
+    }
+
+    case MCExpr::SymbolRef:
+      getSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
+      break;
+
+    case MCExpr::Unary:
+      AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
+      break;
+    }
+
+    return Value;
+  }
+
+  /// @name MCStreamer Interface
+  /// @{
+
+  virtual void SwitchSection(const MCSection *Section);
+  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 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 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 EmitValueToOffset(const MCExpr *Offset,
+                                 unsigned char Value = 0);
+  
+  virtual void EmitFileDirective(StringRef Filename) {
+    errs() << "FIXME: MCMachoStreamer:EmitFileDirective not implemented\n";
+  }
+  virtual void EmitDwarfFileDirective(unsigned FileNo, StringRef Filename) {
+    errs() << "FIXME: MCMachoStreamer:EmitDwarfFileDirective not implemented\n";
+  }
+  
+  virtual void EmitInstruction(const MCInst &Inst);
+  virtual void Finish();
+
+  /// @}
+};
+
+} // end anonymous namespace.
+
+void MCMachOStreamer::SwitchSection(const MCSection *Section) {
+  assert(Section && "Cannot switch to a null section!");
+  
+  // If already in this section, then this is a noop.
+  if (Section == CurSection) return;
+
+  CurSection = Section;
+  CurSectionData = &getSectionData(*Section);
+}
+
+void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
+  assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
+
+  // FIXME: We should also use offsets into Fill fragments.
+  MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
+  if (!F)
+    F = new MCDataFragment(CurSectionData);
+
+  MCSymbolData &SD = getSymbolData(*Symbol);
+  assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
+  SD.setFragment(F);
+  SD.setOffset(F->getContents().size());
+
+  // This causes the reference type and weak reference flags to be cleared.
+  SD.setFlags(SD.getFlags() & ~(SF_WeakReference | SF_ReferenceTypeMask));
+  
+  Symbol->setSection(*CurSection);
+}
+
+void MCMachOStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
+  switch (Flag) {
+  case MCAF_SubsectionsViaSymbols:
+    Assembler.setSubsectionsViaSymbols(true);
+    return;
+  }
+
+  assert(0 && "invalid assembler flag!");
+}
+
+void MCMachOStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
+  // Only absolute symbols can be redefined.
+  assert((Symbol->isUndefined() || Symbol->isAbsolute()) &&
+         "Cannot define a symbol twice!");
+
+  // FIXME: Lift context changes into super class.
+  // FIXME: Set associated section.
+  Symbol->setValue(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 = CurSectionData;
+    Assembler.getIndirectSymbols().push_back(ISD);
+    return;
+  }
+
+  // Adding a symbol attribute always introduces the symbol, note that an
+  // important side effect of calling getSymbolData here is to register the
+  // symbol with the assembler.
+  MCSymbolData &SD = getSymbolData(*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);
+    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;
+  }
+}
+
+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!");
+  getSymbolData(*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 = getSymbolData(*Symbol);
+  SD.setExternal(true);
+  SD.setCommon(Size, ByteAlignment);
+}
+
+void MCMachOStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
+                                   unsigned Size, unsigned ByteAlignment) {
+  MCSectionData &SectData = getSectionData(*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 = getSymbolData(*Symbol);
+
+  MCFragment *F = new MCZeroFillFragment(Size, ByteAlignment, &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);
+}
+
+void MCMachOStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
+  MCDataFragment *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
+  if (!DF)
+    DF = new MCDataFragment(CurSectionData);
+  DF->getContents().append(Data.begin(), Data.end());
+}
+
+void MCMachOStreamer::EmitValue(const MCExpr *Value, unsigned Size,
+                                unsigned AddrSpace) {
+  new MCFillFragment(*AddValueSymbols(Value), Size, 1, CurSectionData);
+}
+
+void MCMachOStreamer::EmitValueToAlignment(unsigned ByteAlignment,
+                                           int64_t Value, unsigned ValueSize,
+                                           unsigned MaxBytesToEmit) {
+  if (MaxBytesToEmit == 0)
+    MaxBytesToEmit = ByteAlignment;
+  new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
+                      CurSectionData);
+
+  // Update the maximum alignment on the current section if necessary.
+  if (ByteAlignment > CurSectionData->getAlignment())
+    CurSectionData->setAlignment(ByteAlignment);
+}
+
+void MCMachOStreamer::EmitValueToOffset(const MCExpr *Offset,
+                                        unsigned char Value) {
+  new MCOrgFragment(*Offset, Value, CurSectionData);
+}
+
+void MCMachOStreamer::EmitInstruction(const MCInst &Inst) {
+  // Scan for values.
+  for (unsigned i = 0; i != Inst.getNumOperands(); ++i)
+    if (Inst.getOperand(i).isExpr())
+      AddValueSymbols(Inst.getOperand(i).getExpr());
+
+  if (!Emitter)
+    llvm_unreachable("no code emitter available!");
+
+  CurSectionData->setHasInstructions(true);
+
+  // FIXME: Relocations!
+  SmallVector<MCFixup, 4> Fixups;
+  SmallString<256> Code;
+  raw_svector_ostream VecOS(Code);
+  Emitter->EncodeInstruction(Inst, VecOS, Fixups);
+  EmitBytes(VecOS.str(), 0);
+}
+
+void MCMachOStreamer::Finish() {
+  Assembler.Finish();
+}
+
+MCStreamer *llvm::createMachOStreamer(MCContext &Context, raw_ostream &OS,
+                                      MCCodeEmitter *CE) {
+  return new MCMachOStreamer(Context, OS, CE);
+}