Split out DwarfFile from DwarfDebug into its own .h/.cpp files.

Some of these types (DwarfDebug in particular) are quite large to begin
with (and I keep forgetting whether DwarfFile is in DwarfDebug or
DwarfUnit... ) so having a few smaller files seems like goodness.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207010 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/CMakeLists.txt

@@ -9,6 +9,7 @@ add_llvm_library(LLVMAsmPrinter
   DwarfCFIException.cpp
   DwarfDebug.cpp
   DwarfException.cpp
+  DwarfFile.cpp
   DwarfUnit.cpp
   ErlangGCPrinter.cpp
   OcamlGCPrinter.cpp

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -108,8 +108,6 @@ static const char *const DbgTimerName = "DWARF Debug Writer";
 
 //===----------------------------------------------------------------------===//
 
-namespace llvm {
-
 /// resolve - Look in the DwarfDebug map for the MDNode that
 /// corresponds to the reference.
 template <typename T> T DbgVariable::resolve(DIRef<T> Ref) const {
@@ -167,8 +165,6 @@ DIType DbgVariable::getType() const {
   return Ty;
 }
 
-} // end llvm namespace
-
 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
     : Asm(A), MMI(Asm->MMI), FirstCU(0), PrevLabel(NULL), GlobalRangeCount(0),
       InfoHolder(A, "info_string", DIEValueAllocator),
@@ -225,65 +221,6 @@ static MCSymbol *emitSectionSym(AsmPrinter *Asm, const MCSection *Section,
   return TmpSym;
 }
 
-DwarfFile::DwarfFile(AsmPrinter *AP, const char *Pref, BumpPtrAllocator &DA)
-    : Asm(AP), StringPool(DA), NextStringPoolNumber(0), StringPref(Pref) {}
-DwarfFile::~DwarfFile() {
-}
-
-MCSymbol *DwarfFile::getStringPoolSym() {
-  return Asm->GetTempSymbol(StringPref);
-}
-
-MCSymbol *DwarfFile::getStringPoolEntry(StringRef Str) {
-  std::pair<MCSymbol *, unsigned> &Entry =
-      StringPool.GetOrCreateValue(Str).getValue();
-  if (Entry.first)
-    return Entry.first;
-
-  Entry.second = NextStringPoolNumber++;
-  return Entry.first = Asm->GetTempSymbol(StringPref, Entry.second);
-}
-
-unsigned DwarfFile::getStringPoolIndex(StringRef Str) {
-  std::pair<MCSymbol *, unsigned> &Entry =
-      StringPool.GetOrCreateValue(Str).getValue();
-  if (Entry.first)
-    return Entry.second;
-
-  Entry.second = NextStringPoolNumber++;
-  Entry.first = Asm->GetTempSymbol(StringPref, Entry.second);
-  return Entry.second;
-}
-
-unsigned DwarfFile::getAddrPoolIndex(const MCSymbol *Sym, bool TLS) {
-  std::pair<AddrPool::iterator, bool> P = AddressPool.insert(
-      std::make_pair(Sym, AddressPoolEntry(AddressPool.size(), TLS)));
-  return P.first->second.Number;
-}
-
-// Define a unique number for the abbreviation.
-//
-void DwarfFile::assignAbbrevNumber(DIEAbbrev &Abbrev) {
-  // Check the set for priors.
-  DIEAbbrev *InSet = AbbreviationsSet.GetOrInsertNode(&Abbrev);
-
-  // If it's newly added.
-  if (InSet == &Abbrev) {
-    // Add to abbreviation list.
-    Abbreviations.push_back(&Abbrev);
-
-    // Assign the vector position + 1 as its number.
-    Abbrev.setNumber(Abbreviations.size());
-  } else {
-    // Assign existing abbreviation number.
-    Abbrev.setNumber(InSet->getNumber());
-  }
-}
-
-void DwarfFile::addUnit(std::unique_ptr<DwarfUnit> U) {
-  CUs.push_back(std::move(U));
-}
-
 static bool isObjCClass(StringRef Name) {
   return Name.startswith("+") || Name.startswith("-");
 }
@@ -1790,68 +1727,6 @@ void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
 // Emit Methods
 //===----------------------------------------------------------------------===//
 
-// Compute the size and offset of a DIE. The offset is relative to start of the
-// CU. It returns the offset after laying out the DIE.
-unsigned DwarfFile::computeSizeAndOffset(DIE &Die, unsigned Offset) {
-  // Record the abbreviation.
-  assignAbbrevNumber(Die.getAbbrev());
-
-  // Get the abbreviation for this DIE.
-  const DIEAbbrev &Abbrev = Die.getAbbrev();
-
-  // Set DIE offset
-  Die.setOffset(Offset);
-
-  // Start the size with the size of abbreviation code.
-  Offset += getULEB128Size(Die.getAbbrevNumber());
-
-  const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
-  const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
-
-  // Size the DIE attribute values.
-  for (unsigned i = 0, N = Values.size(); i < N; ++i)
-    // Size attribute value.
-    Offset += Values[i]->SizeOf(Asm, AbbrevData[i].getForm());
-
-  // Get the children.
-  const auto &Children = Die.getChildren();
-
-  // Size the DIE children if any.
-  if (!Children.empty()) {
-    assert(Abbrev.hasChildren() && "Children flag not set");
-
-    for (auto &Child : Children)
-      Offset = computeSizeAndOffset(*Child, Offset);
-
-    // End of children marker.
-    Offset += sizeof(int8_t);
-  }
-
-  Die.setSize(Offset - Die.getOffset());
-  return Offset;
-}
-
-// Compute the size and offset for each DIE.
-void DwarfFile::computeSizeAndOffsets() {
-  // Offset from the first CU in the debug info section is 0 initially.
-  unsigned SecOffset = 0;
-
-  // Iterate over each compile unit and set the size and offsets for each
-  // DIE within each compile unit. All offsets are CU relative.
-  for (const auto &TheU : CUs) {
-    TheU->setDebugInfoOffset(SecOffset);
-
-    // CU-relative offset is reset to 0 here.
-    unsigned Offset = sizeof(int32_t) +      // Length of Unit Info
-                      TheU->getHeaderSize(); // Unit-specific headers
-
-    // EndOffset here is CU-relative, after laying out
-    // all of the CU DIE.
-    unsigned EndOffset = computeSizeAndOffset(*TheU->getUnitDie(), Offset);
-    SecOffset += EndOffset;
-  }
-}
-
 // Emit initial Dwarf sections with a label at the start of each one.
 void DwarfDebug::emitSectionLabels() {
   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
@@ -1941,28 +1816,6 @@ void DwarfDebug::emitDIE(DIE &Die) {
   }
 }
 
-// Emit the various dwarf units to the unit section USection with
-// the abbreviations going into ASection.
-void DwarfFile::emitUnits(DwarfDebug *DD, const MCSymbol *ASectionSym) {
-  for (const auto &TheU : CUs) {
-    DIE *Die = TheU->getUnitDie();
-    const MCSection *USection = TheU->getSection();
-    Asm->OutStreamer.SwitchSection(USection);
-
-    // Emit the compile units header.
-    Asm->OutStreamer.EmitLabel(TheU->getLabelBegin());
-
-    // Emit size of content not including length itself
-    Asm->OutStreamer.AddComment("Length of Unit");
-    Asm->EmitInt32(TheU->getHeaderSize() + Die->getSize());
-
-    TheU->emitHeader(ASectionSym);
-
-    DD->emitDIE(*Die);
-    Asm->OutStreamer.EmitLabel(TheU->getLabelEnd());
-  }
-}
-
 // Emit the debug info section.
 void DwarfDebug::emitDebugInfo() {
   DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
@@ -1977,26 +1830,6 @@ void DwarfDebug::emitAbbreviations() {
   Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection());
 }
 
-void DwarfFile::emitAbbrevs(const MCSection *Section) {
-  // Check to see if it is worth the effort.
-  if (!Abbreviations.empty()) {
-    // Start the debug abbrev section.
-    Asm->OutStreamer.SwitchSection(Section);
-
-    // For each abbrevation.
-    for (const DIEAbbrev *Abbrev : Abbreviations) {
-      // Emit the abbrevations code (base 1 index.)
-      Asm->EmitULEB128(Abbrev->getNumber(), "Abbreviation Code");
-
-      // Emit the abbreviations data.
-      Abbrev->Emit(Asm);
-    }
-
-    // Mark end of abbreviations.
-    Asm->EmitULEB128(0, "EOM(3)");
-  }
-}
-
 // Emit the last address of the section and the end of the line matrix.
 void DwarfDebug::emitEndOfLineMatrix(unsigned SectionEnd) {
   // Define last address of section.
@@ -2252,69 +2085,6 @@ void DwarfDebug::emitDebugPubTypes(bool GnuStyle) {
   emitDebugPubSection(GnuStyle, PSec, "Types", &DwarfUnit::getGlobalTypes);
 }
 
-// Emit strings into a string section.
-void DwarfFile::emitStrings(const MCSection *StrSection,
-                            const MCSection *OffsetSection = NULL,
-                            const MCSymbol *StrSecSym = NULL) {
-
-  if (StringPool.empty())
-    return;
-
-  // Start the dwarf str section.
-  Asm->OutStreamer.SwitchSection(StrSection);
-
-  // Get all of the string pool entries and put them in an array by their ID so
-  // we can sort them.
-  SmallVector<std::pair<unsigned, const StrPool::value_type *>, 64 > Entries;
-
-  for (const auto &I : StringPool)
-    Entries.push_back(std::make_pair(I.second.second, &I));
-
-  array_pod_sort(Entries.begin(), Entries.end());
-
-  for (const auto &Entry : Entries) {
-    // Emit a label for reference from debug information entries.
-    Asm->OutStreamer.EmitLabel(Entry.second->getValue().first);
-
-    // Emit the string itself with a terminating null byte.
-    Asm->OutStreamer.EmitBytes(StringRef(Entry.second->getKeyData(),
-                                         Entry.second->getKeyLength() + 1));
-  }
-
-  // If we've got an offset section go ahead and emit that now as well.
-  if (OffsetSection) {
-    Asm->OutStreamer.SwitchSection(OffsetSection);
-    unsigned offset = 0;
-    unsigned size = 4; // FIXME: DWARF64 is 8.
-    for (const auto &Entry : Entries) {
-      Asm->OutStreamer.EmitIntValue(offset, size);
-      offset += Entry.second->getKeyLength() + 1;
-    }
-  }
-}
-
-// Emit addresses into the section given.
-void DwarfFile::emitAddresses(const MCSection *AddrSection) {
-
-  if (AddressPool.empty())
-    return;
-
-  // Start the dwarf addr section.
-  Asm->OutStreamer.SwitchSection(AddrSection);
-
-  // Order the address pool entries by ID
-  SmallVector<const MCExpr *, 64> Entries(AddressPool.size());
-
-  for (const auto &I : AddressPool)
-    Entries[I.second.Number] =
-        I.second.TLS
-            ? Asm->getObjFileLowering().getDebugThreadLocalSymbol(I.first)
-            : MCSymbolRefExpr::Create(I.first, Asm->OutContext);
-
-  for (const MCExpr *Entry : Entries)
-    Asm->OutStreamer.EmitValue(Entry, Asm->getDataLayout().getPointerSize());
-}
-
 // Emit visible names into a debug str section.
 void DwarfDebug::emitDebugStr() {
   DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;

lib/CodeGen/AsmPrinter/DwarfDebug.h

@@ -14,6 +14,7 @@
 #ifndef CODEGEN_ASMPRINTER_DWARFDEBUG_H__
 #define CODEGEN_ASMPRINTER_DWARFDEBUG_H__
 
+#include "DwarfFile.h"
 #include "AsmPrinterHandler.h"
 #include "DIE.h"
 #include "DebugLocEntry.h"
@@ -133,96 +134,6 @@ private:
   template <typename T> T resolve(DIRef<T> Ref) const;
 };
 
-/// \brief Collects and handles information specific to a particular
-/// collection of units. This collection represents all of the units
-/// that will be ultimately output into a single object file.
-class DwarfFile {
-  // Target of Dwarf emission, used for sizing of abbreviations.
-  AsmPrinter *Asm;
-
-  // Used to uniquely define abbreviations.
-  FoldingSet<DIEAbbrev> AbbreviationsSet;
-
-  // A list of all the unique abbreviations in use.
-  std::vector<DIEAbbrev *> Abbreviations;
-
-  // A pointer to all units in the section.
-  SmallVector<std::unique_ptr<DwarfUnit>, 1> CUs;
-
-  // Collection of strings for this unit and assorted symbols.
-  // A String->Symbol mapping of strings used by indirect
-  // references.
-  typedef StringMap<std::pair<MCSymbol *, unsigned>, BumpPtrAllocator &>
-  StrPool;
-  StrPool StringPool;
-  unsigned NextStringPoolNumber;
-  std::string StringPref;
-
-  struct AddressPoolEntry {
-    unsigned Number;
-    bool TLS;
-    AddressPoolEntry(unsigned Number, bool TLS) : Number(Number), TLS(TLS) {}
-  };
-  // Collection of addresses for this unit and assorted labels.
-  // A Symbol->unsigned mapping of addresses used by indirect
-  // references.
-  typedef DenseMap<const MCSymbol *, AddressPoolEntry> AddrPool;
-  AddrPool AddressPool;
-
-public:
-  DwarfFile(AsmPrinter *AP, const char *Pref, BumpPtrAllocator &DA);
-
-  ~DwarfFile();
-
-  const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() { return CUs; }
-
-  /// \brief Compute the size and offset of a DIE given an incoming Offset.
-  unsigned computeSizeAndOffset(DIE &Die, unsigned Offset);
-
-  /// \brief Compute the size and offset of all the DIEs.
-  void computeSizeAndOffsets();
-
-  /// \brief Define a unique number for the abbreviation.
-  void assignAbbrevNumber(DIEAbbrev &Abbrev);
-
-  /// \brief Add a unit to the list of CUs.
-  void addUnit(std::unique_ptr<DwarfUnit> U);
-
-  /// \brief Emit all of the units to the section listed with the given
-  /// abbreviation section.
-  void emitUnits(DwarfDebug *DD, const MCSymbol *ASectionSym);
-
-  /// \brief Emit a set of abbreviations to the specific section.
-  void emitAbbrevs(const MCSection *);
-
-  /// \brief Emit all of the strings to the section given.
-  void emitStrings(const MCSection *StrSection, const MCSection *OffsetSection,
-                   const MCSymbol *StrSecSym);
-
-  /// \brief Emit all of the addresses to the section given.
-  void emitAddresses(const MCSection *AddrSection);
-
-  /// \brief Returns the entry into the start of the pool.
-  MCSymbol *getStringPoolSym();
-
-  /// \brief Returns an entry into the string pool with the given
-  /// string text.
-  MCSymbol *getStringPoolEntry(StringRef Str);
-
-  /// \brief Returns the index into the string pool with the given
-  /// string text.
-  unsigned getStringPoolIndex(StringRef Str);
-
-  /// \brief Returns the string pool.
-  StrPool *getStringPool() { return &StringPool; }
-
-  /// \brief Returns the index into the address pool with the given
-  /// label/symbol.
-  unsigned getAddrPoolIndex(const MCSymbol *Sym, bool TLS = false);
-
-  /// \brief Returns the address pool.
-  AddrPool *getAddrPool() { return &AddressPool; }
-};
 
 /// \brief Helper used to pair up a symbol and its DWARF compile unit.
 struct SymbolCU {

lib/CodeGen/AsmPrinter/DwarfFile.cpp

@@ -0,0 +1,244 @@
+//===-- llvm/CodeGen/DwarfFile.cpp - Dwarf Debug Framework ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DwarfFile.h"
+
+#include "DwarfDebug.h"
+#include "DwarfUnit.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
+
+namespace llvm {
+DwarfFile::DwarfFile(AsmPrinter *AP, const char *Pref, BumpPtrAllocator &DA)
+    : Asm(AP), StringPool(DA), NextStringPoolNumber(0), StringPref(Pref) {}
+
+DwarfFile::~DwarfFile() {
+}
+
+MCSymbol *DwarfFile::getStringPoolSym() {
+  return Asm->GetTempSymbol(StringPref);
+}
+
+MCSymbol *DwarfFile::getStringPoolEntry(StringRef Str) {
+  std::pair<MCSymbol *, unsigned> &Entry =
+      StringPool.GetOrCreateValue(Str).getValue();
+  if (Entry.first)
+    return Entry.first;
+
+  Entry.second = NextStringPoolNumber++;
+  return Entry.first = Asm->GetTempSymbol(StringPref, Entry.second);
+}
+
+unsigned DwarfFile::getStringPoolIndex(StringRef Str) {
+  std::pair<MCSymbol *, unsigned> &Entry =
+      StringPool.GetOrCreateValue(Str).getValue();
+  if (Entry.first)
+    return Entry.second;
+
+  Entry.second = NextStringPoolNumber++;
+  Entry.first = Asm->GetTempSymbol(StringPref, Entry.second);
+  return Entry.second;
+}
+
+unsigned DwarfFile::getAddrPoolIndex(const MCSymbol *Sym, bool TLS) {
+  std::pair<AddrPool::iterator, bool> P = AddressPool.insert(
+      std::make_pair(Sym, AddressPoolEntry(AddressPool.size(), TLS)));
+  return P.first->second.Number;
+}
+
+// Define a unique number for the abbreviation.
+//
+void DwarfFile::assignAbbrevNumber(DIEAbbrev &Abbrev) {
+  // Check the set for priors.
+  DIEAbbrev *InSet = AbbreviationsSet.GetOrInsertNode(&Abbrev);
+
+  // If it's newly added.
+  if (InSet == &Abbrev) {
+    // Add to abbreviation list.
+    Abbreviations.push_back(&Abbrev);
+
+    // Assign the vector position + 1 as its number.
+    Abbrev.setNumber(Abbreviations.size());
+  } else {
+    // Assign existing abbreviation number.
+    Abbrev.setNumber(InSet->getNumber());
+  }
+}
+
+void DwarfFile::addUnit(std::unique_ptr<DwarfUnit> U) {
+  CUs.push_back(std::move(U));
+}
+
+// Emit the various dwarf units to the unit section USection with
+// the abbreviations going into ASection.
+void DwarfFile::emitUnits(DwarfDebug *DD, const MCSymbol *ASectionSym) {
+  for (const auto &TheU : CUs) {
+    DIE *Die = TheU->getUnitDie();
+    const MCSection *USection = TheU->getSection();
+    Asm->OutStreamer.SwitchSection(USection);
+
+    // Emit the compile units header.
+    Asm->OutStreamer.EmitLabel(TheU->getLabelBegin());
+
+    // Emit size of content not including length itself
+    Asm->OutStreamer.AddComment("Length of Unit");
+    Asm->EmitInt32(TheU->getHeaderSize() + Die->getSize());
+
+    TheU->emitHeader(ASectionSym);
+
+    DD->emitDIE(*Die);
+    Asm->OutStreamer.EmitLabel(TheU->getLabelEnd());
+  }
+}
+// Compute the size and offset for each DIE.
+void DwarfFile::computeSizeAndOffsets() {
+  // Offset from the first CU in the debug info section is 0 initially.
+  unsigned SecOffset = 0;
+
+  // Iterate over each compile unit and set the size and offsets for each
+  // DIE within each compile unit. All offsets are CU relative.
+  for (const auto &TheU : CUs) {
+    TheU->setDebugInfoOffset(SecOffset);
+
+    // CU-relative offset is reset to 0 here.
+    unsigned Offset = sizeof(int32_t) +      // Length of Unit Info
+                      TheU->getHeaderSize(); // Unit-specific headers
+
+    // EndOffset here is CU-relative, after laying out
+    // all of the CU DIE.
+    unsigned EndOffset = computeSizeAndOffset(*TheU->getUnitDie(), Offset);
+    SecOffset += EndOffset;
+  }
+}
+// Compute the size and offset of a DIE. The offset is relative to start of the
+// CU. It returns the offset after laying out the DIE.
+unsigned DwarfFile::computeSizeAndOffset(DIE &Die, unsigned Offset) {
+  // Record the abbreviation.
+  assignAbbrevNumber(Die.getAbbrev());
+
+  // Get the abbreviation for this DIE.
+  const DIEAbbrev &Abbrev = Die.getAbbrev();
+
+  // Set DIE offset
+  Die.setOffset(Offset);
+
+  // Start the size with the size of abbreviation code.
+  Offset += getULEB128Size(Die.getAbbrevNumber());
+
+  const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
+  const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
+
+  // Size the DIE attribute values.
+  for (unsigned i = 0, N = Values.size(); i < N; ++i)
+    // Size attribute value.
+    Offset += Values[i]->SizeOf(Asm, AbbrevData[i].getForm());
+
+  // Get the children.
+  const auto &Children = Die.getChildren();
+
+  // Size the DIE children if any.
+  if (!Children.empty()) {
+    assert(Abbrev.hasChildren() && "Children flag not set");
+
+    for (auto &Child : Children)
+      Offset = computeSizeAndOffset(*Child, Offset);
+
+    // End of children marker.
+    Offset += sizeof(int8_t);
+  }
+
+  Die.setSize(Offset - Die.getOffset());
+  return Offset;
+}
+void DwarfFile::emitAbbrevs(const MCSection *Section) {
+  // Check to see if it is worth the effort.
+  if (!Abbreviations.empty()) {
+    // Start the debug abbrev section.
+    Asm->OutStreamer.SwitchSection(Section);
+
+    // For each abbrevation.
+    for (const DIEAbbrev *Abbrev : Abbreviations) {
+      // Emit the abbrevations code (base 1 index.)
+      Asm->EmitULEB128(Abbrev->getNumber(), "Abbreviation Code");
+
+      // Emit the abbreviations data.
+      Abbrev->Emit(Asm);
+    }
+
+    // Mark end of abbreviations.
+    Asm->EmitULEB128(0, "EOM(3)");
+  }
+}
+
+// Emit strings into a string section.
+void DwarfFile::emitStrings(const MCSection *StrSection,
+                            const MCSection *OffsetSection,
+                            const MCSymbol *StrSecSym) {
+
+  if (StringPool.empty())
+    return;
+
+  // Start the dwarf str section.
+  Asm->OutStreamer.SwitchSection(StrSection);
+
+  // Get all of the string pool entries and put them in an array by their ID so
+  // we can sort them.
+  SmallVector<std::pair<unsigned, const StrPool::value_type *>, 64 > Entries;
+
+  for (const auto &I : StringPool)
+    Entries.push_back(std::make_pair(I.second.second, &I));
+
+  array_pod_sort(Entries.begin(), Entries.end());
+
+  for (const auto &Entry : Entries) {
+    // Emit a label for reference from debug information entries.
+    Asm->OutStreamer.EmitLabel(Entry.second->getValue().first);
+
+    // Emit the string itself with a terminating null byte.
+    Asm->OutStreamer.EmitBytes(StringRef(Entry.second->getKeyData(),
+                                         Entry.second->getKeyLength() + 1));
+  }
+
+  // If we've got an offset section go ahead and emit that now as well.
+  if (OffsetSection) {
+    Asm->OutStreamer.SwitchSection(OffsetSection);
+    unsigned offset = 0;
+    unsigned size = 4; // FIXME: DWARF64 is 8.
+    for (const auto &Entry : Entries) {
+      Asm->OutStreamer.EmitIntValue(offset, size);
+      offset += Entry.second->getKeyLength() + 1;
+    }
+  }
+}
+
+// Emit addresses into the section given.
+void DwarfFile::emitAddresses(const MCSection *AddrSection) {
+
+  if (AddressPool.empty())
+    return;
+
+  // Start the dwarf addr section.
+  Asm->OutStreamer.SwitchSection(AddrSection);
+
+  // Order the address pool entries by ID
+  SmallVector<const MCExpr *, 64> Entries(AddressPool.size());
+
+  for (const auto &I : AddressPool)
+    Entries[I.second.Number] =
+        I.second.TLS
+            ? Asm->getObjFileLowering().getDebugThreadLocalSymbol(I.first)
+            : MCSymbolRefExpr::Create(I.first, Asm->OutContext);
+
+  for (const MCExpr *Entry : Entries)
+    Asm->OutStreamer.EmitValue(Entry, Asm->getDataLayout().getPointerSize());
+}
+}

lib/CodeGen/AsmPrinter/DwarfFile.h

@@ -0,0 +1,121 @@
+//===-- llvm/CodeGen/DwarfFile.h - Dwarf Debug Framework -------*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CODEGEN_ASMPRINTER_DWARFFILE_H__
+#define CODEGEN_ASMPRINTER_DWARFFILE_H__
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/Support/Allocator.h"
+
+#include <vector>
+#include <string>
+#include <memory>
+
+namespace llvm {
+class AsmPrinter;
+class DwarfUnit;
+class DIEAbbrev;
+class MCSymbol;
+class DIE;
+class StringRef;
+class DwarfDebug;
+class MCSection;
+class DwarfFile {
+  // Target of Dwarf emission, used for sizing of abbreviations.
+  AsmPrinter *Asm;
+
+  // Used to uniquely define abbreviations.
+  FoldingSet<DIEAbbrev> AbbreviationsSet;
+
+  // A list of all the unique abbreviations in use.
+  std::vector<DIEAbbrev *> Abbreviations;
+
+  // A pointer to all units in the section.
+  SmallVector<std::unique_ptr<DwarfUnit>, 1> CUs;
+
+  // Collection of strings for this unit and assorted symbols.
+  // A String->Symbol mapping of strings used by indirect
+  // references.
+  typedef StringMap<std::pair<MCSymbol *, unsigned>, BumpPtrAllocator &>
+  StrPool;
+  StrPool StringPool;
+  unsigned NextStringPoolNumber;
+  std::string StringPref;
+
+  struct AddressPoolEntry {
+    unsigned Number;
+    bool TLS;
+    AddressPoolEntry(unsigned Number, bool TLS) : Number(Number), TLS(TLS) {}
+  };
+  // Collection of addresses for this unit and assorted labels.
+  // A Symbol->unsigned mapping of addresses used by indirect
+  // references.
+  typedef DenseMap<const MCSymbol *, AddressPoolEntry> AddrPool;
+  AddrPool AddressPool;
+
+public:
+  DwarfFile(AsmPrinter *AP, const char *Pref, BumpPtrAllocator &DA);
+
+  ~DwarfFile();
+
+  const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() { return CUs; }
+
+  /// \brief Compute the size and offset of a DIE given an incoming Offset.
+  unsigned computeSizeAndOffset(DIE &Die, unsigned Offset);
+
+  /// \brief Compute the size and offset of all the DIEs.
+  void computeSizeAndOffsets();
+
+  /// \brief Define a unique number for the abbreviation.
+  void assignAbbrevNumber(DIEAbbrev &Abbrev);
+
+  /// \brief Add a unit to the list of CUs.
+  void addUnit(std::unique_ptr<DwarfUnit> U);
+
+  /// \brief Emit all of the units to the section listed with the given
+  /// abbreviation section.
+  void emitUnits(DwarfDebug *DD, const MCSymbol *ASectionSym);
+
+  /// \brief Emit a set of abbreviations to the specific section.
+  void emitAbbrevs(const MCSection *);
+
+  /// \brief Emit all of the strings to the section given.
+  void emitStrings(const MCSection *StrSection,
+                   const MCSection *OffsetSection = nullptr,
+                   const MCSymbol *StrSecSym = nullptr);
+
+  /// \brief Emit all of the addresses to the section given.
+  void emitAddresses(const MCSection *AddrSection);
+
+  /// \brief Returns the entry into the start of the pool.
+  MCSymbol *getStringPoolSym();
+
+  /// \brief Returns an entry into the string pool with the given
+  /// string text.
+  MCSymbol *getStringPoolEntry(StringRef Str);
+
+  /// \brief Returns the index into the string pool with the given
+  /// string text.
+  unsigned getStringPoolIndex(StringRef Str);
+
+  /// \brief Returns the string pool.
+  StrPool *getStringPool() { return &StringPool; }
+
+  /// \brief Returns the index into the address pool with the given
+  /// label/symbol.
+  unsigned getAddrPoolIndex(const MCSymbol *Sym, bool TLS = false);
+
+  /// \brief Returns the address pool.
+  AddrPool *getAddrPool() { return &AddressPool; }
+};
+}
+#endif