1 files changed, 874 insertions, 0 deletions

diff --git a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
new file mode 100644
index 000000000000..190b5332375b
--- /dev/null
+++ b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -0,0 +1,874 @@
+//===-- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info --===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements classes used to handle lowerings specific to common
+// object file formats.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
+#include "llvm/GlobalVariable.h"
+#include "llvm/CodeGen/MachineModuleInfoImpls.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCSectionELF.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Target/Mangler.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/Dwarf.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+//                                  ELF
+//===----------------------------------------------------------------------===//
+typedef StringMap<const MCSectionELF*> ELFUniqueMapTy;
+
+TargetLoweringObjectFileELF::~TargetLoweringObjectFileELF() {
+  // If we have the section uniquing map, free it.
+  delete (ELFUniqueMapTy*)UniquingMap;
+}
+
+const MCSection *TargetLoweringObjectFileELF::
+getELFSection(StringRef Section, unsigned Type, unsigned Flags,
+              SectionKind Kind, bool IsExplicit) const {
+  if (UniquingMap == 0)
+    UniquingMap = new ELFUniqueMapTy();
+  ELFUniqueMapTy &Map = *(ELFUniqueMapTy*)UniquingMap;
+
+  // Do the lookup, if we have a hit, return it.
+  const MCSectionELF *&Entry = Map[Section];
+  if (Entry) return Entry;
+
+  return Entry = MCSectionELF::Create(Section, Type, Flags, Kind, IsExplicit,
+                                      getContext());
+}
+
+void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
+                                             const TargetMachine &TM) {
+  if (UniquingMap != 0)
+    ((ELFUniqueMapTy*)UniquingMap)->clear();
+  TargetLoweringObjectFile::Initialize(Ctx, TM);
+
+  BSSSection =
+    getELFSection(".bss", MCSectionELF::SHT_NOBITS,
+                  MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC,
+                  SectionKind::getBSS());
+
+  TextSection =
+    getELFSection(".text", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_EXECINSTR | MCSectionELF::SHF_ALLOC,
+                  SectionKind::getText());
+
+  DataSection =
+    getELFSection(".data", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_WRITE | MCSectionELF::SHF_ALLOC,
+                  SectionKind::getDataRel());
+
+  ReadOnlySection =
+    getELFSection(".rodata", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC,
+                  SectionKind::getReadOnly());
+
+  TLSDataSection =
+    getELFSection(".tdata", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS |
+                  MCSectionELF::SHF_WRITE, SectionKind::getThreadData());
+
+  TLSBSSSection =
+    getELFSection(".tbss", MCSectionELF::SHT_NOBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS |
+                  MCSectionELF::SHF_WRITE, SectionKind::getThreadBSS());
+
+  DataRelSection =
+    getELFSection(".data.rel", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
+                  SectionKind::getDataRel());
+
+  DataRelLocalSection =
+    getELFSection(".data.rel.local", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
+                  SectionKind::getDataRelLocal());
+
+  DataRelROSection =
+    getELFSection(".data.rel.ro", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
+                  SectionKind::getReadOnlyWithRel());
+
+  DataRelROLocalSection =
+    getELFSection(".data.rel.ro.local", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
+                  SectionKind::getReadOnlyWithRelLocal());
+
+  MergeableConst4Section =
+    getELFSection(".rodata.cst4", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE,
+                  SectionKind::getMergeableConst4());
+
+  MergeableConst8Section =
+    getELFSection(".rodata.cst8", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE,
+                  SectionKind::getMergeableConst8());
+
+  MergeableConst16Section =
+    getELFSection(".rodata.cst16", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_MERGE,
+                  SectionKind::getMergeableConst16());
+
+  StaticCtorSection =
+    getELFSection(".ctors", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
+                  SectionKind::getDataRel());
+
+  StaticDtorSection =
+    getELFSection(".dtors", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
+                  SectionKind::getDataRel());
+
+  // Exception Handling Sections.
+
+  // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
+  // it contains relocatable pointers.  In PIC mode, this is probably a big
+  // runtime hit for C++ apps.  Either the contents of the LSDA need to be
+  // adjusted or this should be a data section.
+  LSDASection =
+    getELFSection(".gcc_except_table", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC, SectionKind::getReadOnly());
+  EHFrameSection =
+    getELFSection(".eh_frame", MCSectionELF::SHT_PROGBITS,
+                  MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_WRITE,
+                  SectionKind::getDataRel());
+
+  // Debug Info Sections.
+  DwarfAbbrevSection =
+    getELFSection(".debug_abbrev", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfInfoSection =
+    getELFSection(".debug_info", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfLineSection =
+    getELFSection(".debug_line", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfFrameSection =
+    getELFSection(".debug_frame", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfPubNamesSection =
+    getELFSection(".debug_pubnames", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfPubTypesSection =
+    getELFSection(".debug_pubtypes", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfStrSection =
+    getELFSection(".debug_str", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfLocSection =
+    getELFSection(".debug_loc", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfARangesSection =
+    getELFSection(".debug_aranges", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfRangesSection =
+    getELFSection(".debug_ranges", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+  DwarfMacroInfoSection =
+    getELFSection(".debug_macinfo", MCSectionELF::SHT_PROGBITS, 0,
+                  SectionKind::getMetadata());
+}
+
+
+static SectionKind
+getELFKindForNamedSection(StringRef Name, SectionKind K) {
+  if (Name.empty() || Name[0] != '.') return K;
+
+  // Some lame default implementation based on some magic section names.
+  if (Name == ".bss" ||
+      Name.startswith(".bss.") ||
+      Name.startswith(".gnu.linkonce.b.") ||
+      Name.startswith(".llvm.linkonce.b.") ||
+      Name == ".sbss" ||
+      Name.startswith(".sbss.") ||
+      Name.startswith(".gnu.linkonce.sb.") ||
+      Name.startswith(".llvm.linkonce.sb."))
+    return SectionKind::getBSS();
+
+  if (Name == ".tdata" ||
+      Name.startswith(".tdata.") ||
+      Name.startswith(".gnu.linkonce.td.") ||
+      Name.startswith(".llvm.linkonce.td."))
+    return SectionKind::getThreadData();
+
+  if (Name == ".tbss" ||
+      Name.startswith(".tbss.") ||
+      Name.startswith(".gnu.linkonce.tb.") ||
+      Name.startswith(".llvm.linkonce.tb."))
+    return SectionKind::getThreadBSS();
+
+  return K;
+}
+
+
+static unsigned getELFSectionType(StringRef Name, SectionKind K) {
+
+  if (Name == ".init_array")
+    return MCSectionELF::SHT_INIT_ARRAY;
+
+  if (Name == ".fini_array")
+    return MCSectionELF::SHT_FINI_ARRAY;
+
+  if (Name == ".preinit_array")
+    return MCSectionELF::SHT_PREINIT_ARRAY;
+
+  if (K.isBSS() || K.isThreadBSS())
+    return MCSectionELF::SHT_NOBITS;
+
+  return MCSectionELF::SHT_PROGBITS;
+}
+
+
+static unsigned
+getELFSectionFlags(SectionKind K) {
+  unsigned Flags = 0;
+
+  if (!K.isMetadata())
+    Flags |= MCSectionELF::SHF_ALLOC;
+
+  if (K.isText())
+    Flags |= MCSectionELF::SHF_EXECINSTR;
+
+  if (K.isWriteable())
+    Flags |= MCSectionELF::SHF_WRITE;
+
+  if (K.isThreadLocal())
+    Flags |= MCSectionELF::SHF_TLS;
+
+  // K.isMergeableConst() is left out to honour PR4650
+  if (K.isMergeableCString() || K.isMergeableConst4() ||
+      K.isMergeableConst8() || K.isMergeableConst16())
+    Flags |= MCSectionELF::SHF_MERGE;
+
+  if (K.isMergeableCString())
+    Flags |= MCSectionELF::SHF_STRINGS;
+
+  return Flags;
+}
+
+
+const MCSection *TargetLoweringObjectFileELF::
+getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
+                         Mangler *Mang, const TargetMachine &TM) const {
+  StringRef SectionName = GV->getSection();
+
+  // Infer section flags from the section name if we can.
+  Kind = getELFKindForNamedSection(SectionName, Kind);
+
+  return getELFSection(SectionName,
+                       getELFSectionType(SectionName, Kind),
+                       getELFSectionFlags(Kind), Kind, true);
+}
+
+static const char *getSectionPrefixForUniqueGlobal(SectionKind Kind) {
+  if (Kind.isText())                 return ".gnu.linkonce.t.";
+  if (Kind.isReadOnly())             return ".gnu.linkonce.r.";
+
+  if (Kind.isThreadData())           return ".gnu.linkonce.td.";
+  if (Kind.isThreadBSS())            return ".gnu.linkonce.tb.";
+
+  if (Kind.isDataNoRel())            return ".gnu.linkonce.d.";
+  if (Kind.isDataRelLocal())         return ".gnu.linkonce.d.rel.local.";
+  if (Kind.isDataRel())              return ".gnu.linkonce.d.rel.";
+  if (Kind.isReadOnlyWithRelLocal()) return ".gnu.linkonce.d.rel.ro.local.";
+
+  assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
+  return ".gnu.linkonce.d.rel.ro.";
+}
+
+const MCSection *TargetLoweringObjectFileELF::
+SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
+                       Mangler *Mang, const TargetMachine &TM) const {
+
+  // If this global is linkonce/weak and the target handles this by emitting it
+  // into a 'uniqued' section name, create and return the section now.
+  if (GV->isWeakForLinker() && !Kind.isCommon() && !Kind.isBSS()) {
+    const char *Prefix = getSectionPrefixForUniqueGlobal(Kind);
+    SmallString<128> Name;
+    Name.append(Prefix, Prefix+strlen(Prefix));
+    Mang->getNameWithPrefix(Name, GV, false);
+    return getELFSection(Name.str(), getELFSectionType(Name.str(), Kind),
+                         getELFSectionFlags(Kind), Kind);
+  }
+
+  if (Kind.isText()) return TextSection;
+
+  if (Kind.isMergeable1ByteCString() ||
+      Kind.isMergeable2ByteCString() ||
+      Kind.isMergeable4ByteCString()) {
+
+    // We also need alignment here.
+    // FIXME: this is getting the alignment of the character, not the
+    // alignment of the global!
+    unsigned Align =
+      TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
+
+    const char *SizeSpec = ".rodata.str1.";
+    if (Kind.isMergeable2ByteCString())
+      SizeSpec = ".rodata.str2.";
+    else if (Kind.isMergeable4ByteCString())
+      SizeSpec = ".rodata.str4.";
+    else
+      assert(Kind.isMergeable1ByteCString() && "unknown string width");
+
+
+    std::string Name = SizeSpec + utostr(Align);
+    return getELFSection(Name, MCSectionELF::SHT_PROGBITS,
+                         MCSectionELF::SHF_ALLOC |
+                         MCSectionELF::SHF_MERGE |
+                         MCSectionELF::SHF_STRINGS,
+                         Kind);
+  }
+
+  if (Kind.isMergeableConst()) {
+    if (Kind.isMergeableConst4() && MergeableConst4Section)
+      return MergeableConst4Section;
+    if (Kind.isMergeableConst8() && MergeableConst8Section)
+      return MergeableConst8Section;
+    if (Kind.isMergeableConst16() && MergeableConst16Section)
+      return MergeableConst16Section;
+    return ReadOnlySection;  // .const
+  }
+
+  if (Kind.isReadOnly())             return ReadOnlySection;
+
+  if (Kind.isThreadData())           return TLSDataSection;
+  if (Kind.isThreadBSS())            return TLSBSSSection;
+
+  // Note: we claim that common symbols are put in BSSSection, but they are
+  // really emitted with the magic .comm directive, which creates a symbol table
+  // entry but not a section.
+  if (Kind.isBSS() || Kind.isCommon()) return BSSSection;
+
+  if (Kind.isDataNoRel())            return DataSection;
+  if (Kind.isDataRelLocal())         return DataRelLocalSection;
+  if (Kind.isDataRel())              return DataRelSection;
+  if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
+
+  assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
+  return DataRelROSection;
+}
+
+/// getSectionForConstant - Given a mergeable constant with the
+/// specified size and relocation information, return a section that it
+/// should be placed in.
+const MCSection *TargetLoweringObjectFileELF::
+getSectionForConstant(SectionKind Kind) const {
+  if (Kind.isMergeableConst4() && MergeableConst4Section)
+    return MergeableConst4Section;
+  if (Kind.isMergeableConst8() && MergeableConst8Section)
+    return MergeableConst8Section;
+  if (Kind.isMergeableConst16() && MergeableConst16Section)
+    return MergeableConst16Section;
+  if (Kind.isReadOnly())
+    return ReadOnlySection;
+
+  if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
+  assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
+  return DataRelROSection;
+}
+
+const MCExpr *TargetLoweringObjectFileELF::
+getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
+                             MachineModuleInfo *MMI, unsigned Encoding) const {
+
+  if (Encoding & dwarf::DW_EH_PE_indirect) {
+    MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
+
+    SmallString<128> Name;
+    Mang->getNameWithPrefix(Name, GV, true);
+    Name += ".DW.stub";
+
+    // Add information about the stub reference to ELFMMI so that the stub
+    // gets emitted by the asmprinter.
+    MCSymbol *Sym = getContext().GetOrCreateSymbol(Name.str());
+    MCSymbol *&StubSym = ELFMMI.getGVStubEntry(Sym);
+    if (StubSym == 0) {
+      Name.clear();
+      Mang->getNameWithPrefix(Name, GV, false);
+      StubSym = getContext().GetOrCreateSymbol(Name.str());
+    }
+
+    return TargetLoweringObjectFile::
+      getSymbolForDwarfReference(Sym, MMI,
+                                 Encoding & ~dwarf::DW_EH_PE_indirect);
+  }
+
+  return TargetLoweringObjectFile::
+    getSymbolForDwarfGlobalReference(GV, Mang, MMI, Encoding);
+}
+
+//===----------------------------------------------------------------------===//
+//                                 MachO
+//===----------------------------------------------------------------------===//
+
+typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy;
+
+TargetLoweringObjectFileMachO::~TargetLoweringObjectFileMachO() {
+  // If we have the MachO uniquing map, free it.
+  delete (MachOUniqueMapTy*)UniquingMap;
+}
+
+
+const MCSectionMachO *TargetLoweringObjectFileMachO::
+getMachOSection(StringRef Segment, StringRef Section,
+                unsigned TypeAndAttributes,
+                unsigned Reserved2, SectionKind Kind) const {
+  // We unique sections by their segment/section pair.  The returned section
+  // may not have the same flags as the requested section, if so this should be
+  // diagnosed by the client as an error.
+
+  // Create the map if it doesn't already exist.
+  if (UniquingMap == 0)
+    UniquingMap = new MachOUniqueMapTy();
+  MachOUniqueMapTy &Map = *(MachOUniqueMapTy*)UniquingMap;
+
+  // Form the name to look up.
+  SmallString<64> Name;
+  Name += Segment;
+  Name.push_back(',');
+  Name += Section;
+
+  // Do the lookup, if we have a hit, return it.
+  const MCSectionMachO *&Entry = Map[Name.str()];
+  if (Entry) return Entry;
+
+  // Otherwise, return a new section.
+  return Entry = MCSectionMachO::Create(Segment, Section, TypeAndAttributes,
+                                        Reserved2, Kind, getContext());
+}
+
+
+void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
+                                               const TargetMachine &TM) {
+  if (UniquingMap != 0)
+    ((MachOUniqueMapTy*)UniquingMap)->clear();
+  TargetLoweringObjectFile::Initialize(Ctx, TM);
+
+  TextSection // .text
+    = getMachOSection("__TEXT", "__text",
+                      MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
+                      SectionKind::getText());
+  DataSection // .data
+    = getMachOSection("__DATA", "__data", 0, SectionKind::getDataRel());
+
+  CStringSection // .cstring
+    = getMachOSection("__TEXT", "__cstring", MCSectionMachO::S_CSTRING_LITERALS,
+                      SectionKind::getMergeable1ByteCString());
+  UStringSection
+    = getMachOSection("__TEXT","__ustring", 0,
+                      SectionKind::getMergeable2ByteCString());
+  FourByteConstantSection // .literal4
+    = getMachOSection("__TEXT", "__literal4", MCSectionMachO::S_4BYTE_LITERALS,
+                      SectionKind::getMergeableConst4());
+  EightByteConstantSection // .literal8
+    = getMachOSection("__TEXT", "__literal8", MCSectionMachO::S_8BYTE_LITERALS,
+                      SectionKind::getMergeableConst8());
+
+  // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
+  // to using it in -static mode.
+  SixteenByteConstantSection = 0;
+  if (TM.getRelocationModel() != Reloc::Static &&
+      TM.getTargetData()->getPointerSize() == 32)
+    SixteenByteConstantSection =   // .literal16
+      getMachOSection("__TEXT", "__literal16",MCSectionMachO::S_16BYTE_LITERALS,
+                      SectionKind::getMergeableConst16());
+
+  ReadOnlySection  // .const
+    = getMachOSection("__TEXT", "__const", 0, SectionKind::getReadOnly());
+
+  TextCoalSection
+    = getMachOSection("__TEXT", "__textcoal_nt",
+                      MCSectionMachO::S_COALESCED |
+                      MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
+                      SectionKind::getText());
+  ConstTextCoalSection
+    = getMachOSection("__TEXT", "__const_coal", MCSectionMachO::S_COALESCED,
+                      SectionKind::getText());
+  ConstDataCoalSection
+    = getMachOSection("__DATA","__const_coal", MCSectionMachO::S_COALESCED,
+                      SectionKind::getText());
+  ConstDataSection  // .const_data
+    = getMachOSection("__DATA", "__const", 0,
+                      SectionKind::getReadOnlyWithRel());
+  DataCoalSection
+    = getMachOSection("__DATA","__datacoal_nt", MCSectionMachO::S_COALESCED,
+                      SectionKind::getDataRel());
+  DataCommonSection
+    = getMachOSection("__DATA","__common", MCSectionMachO::S_ZEROFILL,
+                      SectionKind::getBSS());
+  DataBSSSection
+    = getMachOSection("__DATA","__bss", MCSectionMachO::S_ZEROFILL,
+                    SectionKind::getBSS());
+  
+
+  LazySymbolPointerSection
+    = getMachOSection("__DATA", "__la_symbol_ptr",
+                      MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
+                      SectionKind::getMetadata());
+  NonLazySymbolPointerSection
+    = getMachOSection("__DATA", "__nl_symbol_ptr",
+                      MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
+                      SectionKind::getMetadata());
+
+  if (TM.getRelocationModel() == Reloc::Static) {
+    StaticCtorSection
+      = getMachOSection("__TEXT", "__constructor", 0,SectionKind::getDataRel());
+    StaticDtorSection
+      = getMachOSection("__TEXT", "__destructor", 0, SectionKind::getDataRel());
+  } else {
+    StaticCtorSection
+      = getMachOSection("__DATA", "__mod_init_func",
+                        MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
+                        SectionKind::getDataRel());
+    StaticDtorSection
+      = getMachOSection("__DATA", "__mod_term_func",
+                        MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
+                        SectionKind::getDataRel());
+  }
+
+  // Exception Handling.
+  LSDASection = getMachOSection("__DATA", "__gcc_except_tab", 0,
+                                SectionKind::getDataRel());
+  EHFrameSection =
+    getMachOSection("__TEXT", "__eh_frame",
+                    MCSectionMachO::S_COALESCED |
+                    MCSectionMachO::S_ATTR_NO_TOC |
+                    MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
+                    MCSectionMachO::S_ATTR_LIVE_SUPPORT,
+                    SectionKind::getReadOnly());
+
+  // Debug Information.
+  DwarfAbbrevSection =
+    getMachOSection("__DWARF", "__debug_abbrev", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfInfoSection =
+    getMachOSection("__DWARF", "__debug_info", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfLineSection =
+    getMachOSection("__DWARF", "__debug_line", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfFrameSection =
+    getMachOSection("__DWARF", "__debug_frame", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfPubNamesSection =
+    getMachOSection("__DWARF", "__debug_pubnames", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfPubTypesSection =
+    getMachOSection("__DWARF", "__debug_pubtypes", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfStrSection =
+    getMachOSection("__DWARF", "__debug_str", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfLocSection =
+    getMachOSection("__DWARF", "__debug_loc", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfARangesSection =
+    getMachOSection("__DWARF", "__debug_aranges", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfRangesSection =
+    getMachOSection("__DWARF", "__debug_ranges", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfMacroInfoSection =
+    getMachOSection("__DWARF", "__debug_macinfo", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+  DwarfDebugInlineSection =
+    getMachOSection("__DWARF", "__debug_inlined", MCSectionMachO::S_ATTR_DEBUG,
+                    SectionKind::getMetadata());
+}
+
+const MCSection *TargetLoweringObjectFileMachO::
+getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
+                         Mangler *Mang, const TargetMachine &TM) const {
+  // Parse the section specifier and create it if valid.
+  StringRef Segment, Section;
+  unsigned TAA, StubSize;
+  std::string ErrorCode =
+    MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
+                                          TAA, StubSize);
+  if (!ErrorCode.empty()) {
+    // If invalid, report the error with llvm_report_error.
+    llvm_report_error("Global variable '" + GV->getNameStr() +
+                      "' has an invalid section specifier '" + GV->getSection()+
+                      "': " + ErrorCode + ".");
+    // Fall back to dropping it into the data section.
+    return DataSection;
+  }
+
+  // Get the section.
+  const MCSectionMachO *S =
+    getMachOSection(Segment, Section, TAA, StubSize, Kind);
+
+  // Okay, now that we got the section, verify that the TAA & StubSize agree.
+  // If the user declared multiple globals with different section flags, we need
+  // to reject it here.
+  if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
+    // If invalid, report the error with llvm_report_error.
+    llvm_report_error("Global variable '" + GV->getNameStr() +
+                      "' section type or attributes does not match previous"
+                      " section specifier");
+  }
+
+  return S;
+}
+
+const MCSection *TargetLoweringObjectFileMachO::
+SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
+                       Mangler *Mang, const TargetMachine &TM) const {
+  assert(!Kind.isThreadLocal() && "Darwin doesn't support TLS");
+
+  if (Kind.isText())
+    return GV->isWeakForLinker() ? TextCoalSection : TextSection;
+
+  // If this is weak/linkonce, put this in a coalescable section, either in text
+  // or data depending on if it is writable.
+  if (GV->isWeakForLinker()) {
+    if (Kind.isReadOnly())
+      return ConstTextCoalSection;
+    return DataCoalSection;
+  }
+
+  // FIXME: Alignment check should be handled by section classifier.
+  if (Kind.isMergeable1ByteCString() ||
+      Kind.isMergeable2ByteCString()) {
+    if (TM.getTargetData()->getPreferredAlignment(
+                                              cast<GlobalVariable>(GV)) < 32) {
+      if (Kind.isMergeable1ByteCString())
+        return CStringSection;
+      assert(Kind.isMergeable2ByteCString());
+      return UStringSection;
+    }
+  }
+
+  if (Kind.isMergeableConst()) {
+    if (Kind.isMergeableConst4())
+      return FourByteConstantSection;
+    if (Kind.isMergeableConst8())
+      return EightByteConstantSection;
+    if (Kind.isMergeableConst16() && SixteenByteConstantSection)
+      return SixteenByteConstantSection;
+  }
+
+  // Otherwise, if it is readonly, but not something we can specially optimize,
+  // just drop it in .const.
+  if (Kind.isReadOnly())
+    return ReadOnlySection;
+
+  // If this is marked const, put it into a const section.  But if the dynamic
+  // linker needs to write to it, put it in the data segment.
+  if (Kind.isReadOnlyWithRel())
+    return ConstDataSection;
+
+  // Put zero initialized globals with strong external linkage in the
+  // DATA, __common section with the .zerofill directive.
+  if (Kind.isBSSExtern())
+    return DataCommonSection;
+
+  // Put zero initialized globals with local linkage in __DATA,__bss directive
+  // with the .zerofill directive (aka .lcomm).
+  if (Kind.isBSSLocal())
+    return DataBSSSection;
+  
+  // Otherwise, just drop the variable in the normal data section.
+  return DataSection;
+}
+
+const MCSection *
+TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
+  // If this constant requires a relocation, we have to put it in the data
+  // segment, not in the text segment.
+  if (Kind.isDataRel() || Kind.isReadOnlyWithRel())
+    return ConstDataSection;
+
+  if (Kind.isMergeableConst4())
+    return FourByteConstantSection;
+  if (Kind.isMergeableConst8())
+    return EightByteConstantSection;
+  if (Kind.isMergeableConst16() && SixteenByteConstantSection)
+    return SixteenByteConstantSection;
+  return ReadOnlySection;  // .const
+}
+
+/// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
+/// not to emit the UsedDirective for some symbols in llvm.used.
+// FIXME: REMOVE this (rdar://7071300)
+bool TargetLoweringObjectFileMachO::
+shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
+  /// On Darwin, internally linked data beginning with "L" or "l" does not have
+  /// the directive emitted (this occurs in ObjC metadata).
+  if (!GV) return false;
+
+  // Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
+  if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
+    // FIXME: ObjC metadata is currently emitted as internal symbols that have
+    // \1L and \0l prefixes on them.  Fix them to be Private/LinkerPrivate and
+    // this horrible hack can go away.
+    SmallString<64> Name;
+    Mang->getNameWithPrefix(Name, GV, false);
+    if (Name[0] == 'L' || Name[0] == 'l')
+      return false;
+  }
+
+  return true;
+}
+
+const MCExpr *TargetLoweringObjectFileMachO::
+getSymbolForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
+                             MachineModuleInfo *MMI, unsigned Encoding) const {
+  // The mach-o version of this method defaults to returning a stub reference.
+
+  if (Encoding & dwarf::DW_EH_PE_indirect) {
+    SmallString<128> Name;
+    Mang->getNameWithPrefix(Name, GV, true);
+    Name += "$non_lazy_ptr";
+    MCSymbol *Sym = getContext().GetOrCreateSymbol(Name.str());
+
+    return TargetLoweringObjectFile::
+      getSymbolForDwarfReference(Sym, MMI,
+                                 Encoding & ~dwarf::DW_EH_PE_indirect);
+  }
+
+  return TargetLoweringObjectFile::
+    getSymbolForDwarfGlobalReference(GV, Mang, MMI, Encoding);
+}
+
+
+//===----------------------------------------------------------------------===//
+//                                  COFF
+//===----------------------------------------------------------------------===//
+
+typedef StringMap<const MCSectionCOFF*> COFFUniqueMapTy;
+
+TargetLoweringObjectFileCOFF::~TargetLoweringObjectFileCOFF() {
+  delete (COFFUniqueMapTy*)UniquingMap;
+}
+
+
+const MCSection *TargetLoweringObjectFileCOFF::
+getCOFFSection(StringRef Name, bool isDirective, SectionKind Kind) const {
+  // Create the map if it doesn't already exist.
+  if (UniquingMap == 0)
+    UniquingMap = new MachOUniqueMapTy();
+  COFFUniqueMapTy &Map = *(COFFUniqueMapTy*)UniquingMap;
+
+  // Do the lookup, if we have a hit, return it.
+  const MCSectionCOFF *&Entry = Map[Name];
+  if (Entry) return Entry;
+
+  return Entry = MCSectionCOFF::Create(Name, isDirective, Kind, getContext());
+}
+
+void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
+                                              const TargetMachine &TM) {
+  if (UniquingMap != 0)
+    ((COFFUniqueMapTy*)UniquingMap)->clear();
+  TargetLoweringObjectFile::Initialize(Ctx, TM);
+  TextSection = getCOFFSection("\t.text", true, SectionKind::getText());
+  DataSection = getCOFFSection("\t.data", true, SectionKind::getDataRel());
+  StaticCtorSection =
+    getCOFFSection(".ctors", false, SectionKind::getDataRel());
+  StaticDtorSection =
+    getCOFFSection(".dtors", false, SectionKind::getDataRel());
+
+  // FIXME: We're emitting LSDA info into a readonly section on COFF, even
+  // though it contains relocatable pointers.  In PIC mode, this is probably a
+  // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
+  // adjusted or this should be a data section.
+  LSDASection =
+    getCOFFSection(".gcc_except_table", false, SectionKind::getReadOnly());
+  EHFrameSection =
+    getCOFFSection(".eh_frame", false, SectionKind::getDataRel());
+
+  // Debug info.
+  // FIXME: Don't use 'directive' mode here.
+  DwarfAbbrevSection =
+    getCOFFSection("\t.section\t.debug_abbrev,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfInfoSection =
+    getCOFFSection("\t.section\t.debug_info,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfLineSection =
+    getCOFFSection("\t.section\t.debug_line,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfFrameSection =
+    getCOFFSection("\t.section\t.debug_frame,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfPubNamesSection =
+    getCOFFSection("\t.section\t.debug_pubnames,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfPubTypesSection =
+    getCOFFSection("\t.section\t.debug_pubtypes,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfStrSection =
+    getCOFFSection("\t.section\t.debug_str,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfLocSection =
+    getCOFFSection("\t.section\t.debug_loc,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfARangesSection =
+    getCOFFSection("\t.section\t.debug_aranges,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfRangesSection =
+    getCOFFSection("\t.section\t.debug_ranges,\"dr\"",
+                   true, SectionKind::getMetadata());
+  DwarfMacroInfoSection =
+    getCOFFSection("\t.section\t.debug_macinfo,\"dr\"",
+                   true, SectionKind::getMetadata());
+}
+
+const MCSection *TargetLoweringObjectFileCOFF::
+getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
+                         Mangler *Mang, const TargetMachine &TM) const {
+  return getCOFFSection(GV->getSection(), false, Kind);
+}
+
+static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
+  if (Kind.isText())
+    return ".text$linkonce";
+  if (Kind.isWriteable())
+    return ".data$linkonce";
+  return ".rdata$linkonce";
+}
+
+
+const MCSection *TargetLoweringObjectFileCOFF::
+SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
+                       Mangler *Mang, const TargetMachine &TM) const {
+  assert(!Kind.isThreadLocal() && "Doesn't support TLS");
+
+  // If this global is linkonce/weak and the target handles this by emitting it
+  // into a 'uniqued' section name, create and return the section now.
+  if (GV->isWeakForLinker()) {
+    const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
+    SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
+    Mang->getNameWithPrefix(Name, GV, false);
+    return getCOFFSection(Name.str(), false, Kind);
+  }
+
+  if (Kind.isText())
+    return getTextSection();
+
+  return getDataSection();
+}
+