X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FMC%2FMCAssembler.h;h=0116aed2442cb69d063ac09c28541259efd7f9c1;hb=7521964d28c5ccb28431aed23334638138d9bd0a;hp=fc919669e82dd4567dd1035e58c43b9994b88c43;hpb=7a2bdde0a0eebcd2125055e0eacaca040f0b766c;p=oota-llvm.git

diff --git a/include/llvm/MC/MCAssembler.h b/include/llvm/MC/MCAssembler.h
index fc919669e82..0116aed2442 100644
--- a/include/llvm/MC/MCAssembler.h
+++ b/include/llvm/MC/MCAssembler.h
@@ -11,21 +11,27 @@
 #define LLVM_MC_MCASSEMBLER_H
 
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/ilist.h"
 #include "llvm/ADT/ilist_node.h"
-#include "llvm/Support/Casting.h"
+#include "llvm/ADT/iterator.h"
+#include "llvm/MC/MCDirectives.h"
 #include "llvm/MC/MCFixup.h"
 #include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCLinkerOptimizationHint.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Support/Casting.h"
 #include "llvm/Support/DataTypes.h"
+#include <algorithm>
 #include <vector> // FIXME: Shouldn't be needed.
 
 namespace llvm {
 class raw_ostream;
 class MCAsmLayout;
 class MCAssembler;
-class MCBinaryExpr;
 class MCContext;
 class MCCodeEmitter;
 class MCExpr;
@@ -33,23 +39,23 @@ class MCFragment;
 class MCObjectWriter;
 class MCSection;
 class MCSectionData;
-class MCSymbol;
-class MCSymbolData;
+class MCSubtargetInfo;
 class MCValue;
-class TargetAsmBackend;
+class MCAsmBackend;
 
 class MCFragment : public ilist_node<MCFragment> {
   friend class MCAsmLayout;
 
-  MCFragment(const MCFragment&);     // DO NOT IMPLEMENT
-  void operator=(const MCFragment&); // DO NOT IMPLEMENT
+  MCFragment(const MCFragment &) = delete;
+  void operator=(const MCFragment &) = delete;
 
 public:
   enum FragmentType {
     FT_Align,
     FT_Data,
+    FT_CompactEncodedInst,
     FT_Fill,
-    FT_Inst,
+    FT_Relaxable,
     FT_Org,
     FT_Dwarf,
     FT_DwarfFrame,
@@ -63,11 +69,10 @@ private:
   MCSectionData *Parent;
 
   /// Atom - The atom this fragment is in, as represented by it's defining
-  /// symbol. Atom's are only used by backends which set
-  /// \see MCAsmBackend::hasReliableSymbolDifference().
-  MCSymbolData *Atom;
+  /// symbol.
+  const MCSymbol *Atom;
 
-  /// @name Assembler Backend Data
+  /// \name Assembler Backend Data
   /// @{
   //
   // FIXME: This could all be kept private to the assembler implementation.
@@ -82,7 +87,7 @@ private:
   /// @}
 
 protected:
-  MCFragment(FragmentType _Kind, MCSectionData *_Parent = 0);
+  MCFragment(FragmentType Kind, MCSectionData *Parent = nullptr);
 
 public:
   // Only for sentinel.
@@ -94,134 +99,232 @@ public:
   MCSectionData *getParent() const { return Parent; }
   void setParent(MCSectionData *Value) { Parent = Value; }
 
-  MCSymbolData *getAtom() const { return Atom; }
-  void setAtom(MCSymbolData *Value) { Atom = Value; }
+  const MCSymbol *getAtom() const { return Atom; }
+  void setAtom(const MCSymbol *Value) { Atom = Value; }
 
   unsigned getLayoutOrder() const { return LayoutOrder; }
   void setLayoutOrder(unsigned Value) { LayoutOrder = Value; }
 
-  static bool classof(const MCFragment *O) { return true; }
+  /// \brief Does this fragment have instructions emitted into it? By default
+  /// this is false, but specific fragment types may set it to true.
+  virtual bool hasInstructions() const { return false; }
+
+  /// \brief Should this fragment be placed at the end of an aligned bundle?
+  virtual bool alignToBundleEnd() const { return false; }
+  virtual void setAlignToBundleEnd(bool V) {}
+
+  /// \brief Get the padding size that must be inserted before this fragment.
+  /// Used for bundling. By default, no padding is inserted.
+  /// Note that padding size is restricted to 8 bits. This is an optimization
+  /// to reduce the amount of space used for each fragment. In practice, larger
+  /// padding should never be required.
+  virtual uint8_t getBundlePadding() const { return 0; }
+
+  /// \brief Set the padding size for this fragment. By default it's a no-op,
+  /// and only some fragments have a meaningful implementation.
+  virtual void setBundlePadding(uint8_t N) {}
 
   void dump();
 };
 
-class MCDataFragment : public MCFragment {
-  SmallString<32> Contents;
+/// Interface implemented by fragments that contain encoded instructions and/or
+/// data.
+///
+class MCEncodedFragment : public MCFragment {
+  virtual void anchor();
 
-  /// Fixups - The list of fixups in this fragment.
-  std::vector<MCFixup> Fixups;
+  uint8_t BundlePadding;
 
 public:
-  typedef std::vector<MCFixup>::const_iterator const_fixup_iterator;
-  typedef std::vector<MCFixup>::iterator fixup_iterator;
+  MCEncodedFragment(MCFragment::FragmentType FType, MCSectionData *SD = nullptr)
+      : MCFragment(FType, SD), BundlePadding(0) {}
+  ~MCEncodedFragment() override;
+
+  virtual SmallVectorImpl<char> &getContents() = 0;
+  virtual const SmallVectorImpl<char> &getContents() const = 0;
+
+  uint8_t getBundlePadding() const override { return BundlePadding; }
+
+  void setBundlePadding(uint8_t N) override { BundlePadding = N; }
+
+  static bool classof(const MCFragment *F) {
+    MCFragment::FragmentType Kind = F->getKind();
+    switch (Kind) {
+    default:
+      return false;
+    case MCFragment::FT_Relaxable:
+    case MCFragment::FT_CompactEncodedInst:
+    case MCFragment::FT_Data:
+      return true;
+    }
+  }
+};
+
+/// Interface implemented by fragments that contain encoded instructions and/or
+/// data and also have fixups registered.
+///
+class MCEncodedFragmentWithFixups : public MCEncodedFragment {
+  void anchor() override;
 
 public:
-  MCDataFragment(MCSectionData *SD = 0) : MCFragment(FT_Data, SD) {}
+  MCEncodedFragmentWithFixups(MCFragment::FragmentType FType,
+                              MCSectionData *SD = nullptr)
+      : MCEncodedFragment(FType, SD) {}
 
-  /// @name Accessors
-  /// @{
+  ~MCEncodedFragmentWithFixups() override;
 
-  SmallString<32> &getContents() { return Contents; }
-  const SmallString<32> &getContents() const { return Contents; }
+  typedef SmallVectorImpl<MCFixup>::const_iterator const_fixup_iterator;
+  typedef SmallVectorImpl<MCFixup>::iterator fixup_iterator;
 
-  /// @}
-  /// @name Fixup Access
-  /// @{
+  virtual SmallVectorImpl<MCFixup> &getFixups() = 0;
+  virtual const SmallVectorImpl<MCFixup> &getFixups() const = 0;
+
+  virtual fixup_iterator fixup_begin() = 0;
+  virtual const_fixup_iterator fixup_begin() const = 0;
+  virtual fixup_iterator fixup_end() = 0;
+  virtual const_fixup_iterator fixup_end() const = 0;
 
-  void addFixup(MCFixup Fixup) {
-    // Enforce invariant that fixups are in offset order.
-    assert((Fixups.empty() || Fixup.getOffset() > Fixups.back().getOffset()) &&
-           "Fixups must be added in order!");
-    Fixups.push_back(Fixup);
+  static bool classof(const MCFragment *F) {
+    MCFragment::FragmentType Kind = F->getKind();
+    return Kind == MCFragment::FT_Relaxable || Kind == MCFragment::FT_Data;
   }
+};
 
-  std::vector<MCFixup> &getFixups() { return Fixups; }
-  const std::vector<MCFixup> &getFixups() const { return Fixups; }
+/// Fragment for data and encoded instructions.
+///
+class MCDataFragment : public MCEncodedFragmentWithFixups {
+  void anchor() override;
 
-  fixup_iterator fixup_begin() { return Fixups.begin(); }
-  const_fixup_iterator fixup_begin() const { return Fixups.begin(); }
+  /// \brief Does this fragment contain encoded instructions anywhere in it?
+  bool HasInstructions;
 
-  fixup_iterator fixup_end() {return Fixups.end();}
-  const_fixup_iterator fixup_end() const {return Fixups.end();}
+  /// \brief Should this fragment be aligned to the end of a bundle?
+  bool AlignToBundleEnd;
 
-  size_t fixup_size() const { return Fixups.size(); }
+  SmallVector<char, 32> Contents;
 
-  /// @}
+  /// Fixups - The list of fixups in this fragment.
+  SmallVector<MCFixup, 4> Fixups;
+
+public:
+  MCDataFragment(MCSectionData *SD = nullptr)
+      : MCEncodedFragmentWithFixups(FT_Data, SD), HasInstructions(false),
+        AlignToBundleEnd(false) {}
+
+  SmallVectorImpl<char> &getContents() override { return Contents; }
+  const SmallVectorImpl<char> &getContents() const override { return Contents; }
+
+  SmallVectorImpl<MCFixup> &getFixups() override { return Fixups; }
+
+  const SmallVectorImpl<MCFixup> &getFixups() const override { return Fixups; }
+
+  bool hasInstructions() const override { return HasInstructions; }
+  virtual void setHasInstructions(bool V) { HasInstructions = V; }
+
+  bool alignToBundleEnd() const override { return AlignToBundleEnd; }
+  void setAlignToBundleEnd(bool V) override { AlignToBundleEnd = V; }
+
+  fixup_iterator fixup_begin() override { return Fixups.begin(); }
+  const_fixup_iterator fixup_begin() const override { return Fixups.begin(); }
+
+  fixup_iterator fixup_end() override { return Fixups.end(); }
+  const_fixup_iterator fixup_end() const override { return Fixups.end(); }
 
   static bool classof(const MCFragment *F) {
     return F->getKind() == MCFragment::FT_Data;
   }
-  static bool classof(const MCDataFragment *) { return true; }
 };
 
-// FIXME: This current incarnation of MCInstFragment doesn't make much sense, as
-// it is almost entirely a duplicate of MCDataFragment. If we decide to stick
-// with this approach (as opposed to making MCInstFragment a very light weight
-// object with just the MCInst and a code size, then we should just change
-// MCDataFragment to have an optional MCInst at its end.
-class MCInstFragment : public MCFragment {
-  /// Inst - The instruction this is a fragment for.
-  MCInst Inst;
+/// This is a compact (memory-size-wise) fragment for holding an encoded
+/// instruction (non-relaxable) that has no fixups registered. When applicable,
+/// it can be used instead of MCDataFragment and lead to lower memory
+/// consumption.
+///
+class MCCompactEncodedInstFragment : public MCEncodedFragment {
+  void anchor() override;
 
-  /// Code - Binary data for the currently encoded instruction.
-  SmallString<8> Code;
+  /// \brief Should this fragment be aligned to the end of a bundle?
+  bool AlignToBundleEnd;
 
-  /// Fixups - The list of fixups in this fragment.
-  SmallVector<MCFixup, 1> Fixups;
+  SmallVector<char, 4> Contents;
 
 public:
-  typedef SmallVectorImpl<MCFixup>::const_iterator const_fixup_iterator;
-  typedef SmallVectorImpl<MCFixup>::iterator fixup_iterator;
+  MCCompactEncodedInstFragment(MCSectionData *SD = nullptr)
+      : MCEncodedFragment(FT_CompactEncodedInst, SD), AlignToBundleEnd(false) {}
 
-public:
-  MCInstFragment(MCInst _Inst, MCSectionData *SD = 0)
-    : MCFragment(FT_Inst, SD), Inst(_Inst) {
+  bool hasInstructions() const override { return true; }
+
+  SmallVectorImpl<char> &getContents() override { return Contents; }
+  const SmallVectorImpl<char> &getContents() const override { return Contents; }
+
+  bool alignToBundleEnd() const override { return AlignToBundleEnd; }
+  void setAlignToBundleEnd(bool V) override { AlignToBundleEnd = V; }
+
+  static bool classof(const MCFragment *F) {
+    return F->getKind() == MCFragment::FT_CompactEncodedInst;
   }
+};
 
-  /// @name Accessors
-  /// @{
+/// A relaxable fragment holds on to its MCInst, since it may need to be
+/// relaxed during the assembler layout and relaxation stage.
+///
+class MCRelaxableFragment : public MCEncodedFragmentWithFixups {
+  void anchor() override;
 
-  SmallVectorImpl<char> &getCode() { return Code; }
-  const SmallVectorImpl<char> &getCode() const { return Code; }
+  /// Inst - The instruction this is a fragment for.
+  MCInst Inst;
 
-  unsigned getInstSize() const { return Code.size(); }
+  /// STI - The MCSubtargetInfo in effect when the instruction was encoded.
+  /// Keep a copy instead of a reference to make sure that updates to STI
+  /// in the assembler are not seen here.
+  const MCSubtargetInfo STI;
 
-  MCInst &getInst() { return Inst; }
-  const MCInst &getInst() const { return Inst; }
+  /// Contents - Binary data for the currently encoded instruction.
+  SmallVector<char, 8> Contents;
 
-  void setInst(MCInst Value) { Inst = Value; }
+  /// Fixups - The list of fixups in this fragment.
+  SmallVector<MCFixup, 1> Fixups;
 
-  /// @}
-  /// @name Fixup Access
-  /// @{
+public:
+  MCRelaxableFragment(const MCInst &Inst, const MCSubtargetInfo &STI,
+                      MCSectionData *SD = nullptr)
+      : MCEncodedFragmentWithFixups(FT_Relaxable, SD), Inst(Inst), STI(STI) {}
 
-  SmallVectorImpl<MCFixup> &getFixups() { return Fixups; }
-  const SmallVectorImpl<MCFixup> &getFixups() const { return Fixups; }
+  SmallVectorImpl<char> &getContents() override { return Contents; }
+  const SmallVectorImpl<char> &getContents() const override { return Contents; }
 
-  fixup_iterator fixup_begin() { return Fixups.begin(); }
-  const_fixup_iterator fixup_begin() const { return Fixups.begin(); }
+  const MCInst &getInst() const { return Inst; }
+  void setInst(const MCInst &Value) { Inst = Value; }
 
-  fixup_iterator fixup_end() {return Fixups.end();}
-  const_fixup_iterator fixup_end() const {return Fixups.end();}
+  const MCSubtargetInfo &getSubtargetInfo() { return STI; }
 
-  size_t fixup_size() const { return Fixups.size(); }
+  SmallVectorImpl<MCFixup> &getFixups() override { return Fixups; }
 
-  /// @}
+  const SmallVectorImpl<MCFixup> &getFixups() const override { return Fixups; }
+
+  bool hasInstructions() const override { return true; }
+
+  fixup_iterator fixup_begin() override { return Fixups.begin(); }
+  const_fixup_iterator fixup_begin() const override { return Fixups.begin(); }
+
+  fixup_iterator fixup_end() override { return Fixups.end(); }
+  const_fixup_iterator fixup_end() const override { return Fixups.end(); }
 
   static bool classof(const MCFragment *F) {
-    return F->getKind() == MCFragment::FT_Inst;
+    return F->getKind() == MCFragment::FT_Relaxable;
   }
-  static bool classof(const MCInstFragment *) { return true; }
 };
 
 class MCAlignFragment : public MCFragment {
+  virtual void anchor();
+
   /// Alignment - The alignment to ensure, in bytes.
   unsigned Alignment;
 
   /// Value - Value to use for filling padding bytes.
   int64_t Value;
 
-  /// ValueSize - The size of the integer (in bytes) of \arg Value.
+  /// ValueSize - The size of the integer (in bytes) of \p Value.
   unsigned ValueSize;
 
   /// MaxBytesToEmit - The maximum number of bytes to emit; if the alignment
@@ -234,13 +337,12 @@ class MCAlignFragment : public MCFragment {
   bool EmitNops : 1;
 
 public:
-  MCAlignFragment(unsigned _Alignment, int64_t _Value, unsigned _ValueSize,
-                  unsigned _MaxBytesToEmit, MCSectionData *SD = 0)
-    : MCFragment(FT_Align, SD), Alignment(_Alignment),
-      Value(_Value),ValueSize(_ValueSize),
-      MaxBytesToEmit(_MaxBytesToEmit), EmitNops(false) {}
+  MCAlignFragment(unsigned Alignment, int64_t Value, unsigned ValueSize,
+                  unsigned MaxBytesToEmit, MCSectionData *SD = nullptr)
+      : MCFragment(FT_Align, SD), Alignment(Alignment), Value(Value),
+        ValueSize(ValueSize), MaxBytesToEmit(MaxBytesToEmit), EmitNops(false) {}
 
-  /// @name Accessors
+  /// \name Accessors
   /// @{
 
   unsigned getAlignment() const { return Alignment; }
@@ -259,14 +361,15 @@ public:
   static bool classof(const MCFragment *F) {
     return F->getKind() == MCFragment::FT_Align;
   }
-  static bool classof(const MCAlignFragment *) { return true; }
 };
 
 class MCFillFragment : public MCFragment {
+  virtual void anchor();
+
   /// Value - Value to use for filling bytes.
   int64_t Value;
 
-  /// ValueSize - The size (in bytes) of \arg Value to use when filling, or 0 if
+  /// ValueSize - The size (in bytes) of \p Value to use when filling, or 0 if
   /// this is a virtual fill fragment.
   unsigned ValueSize;
 
@@ -274,15 +377,15 @@ class MCFillFragment : public MCFragment {
   uint64_t Size;
 
 public:
-  MCFillFragment(int64_t _Value, unsigned _ValueSize, uint64_t _Size,
-                 MCSectionData *SD = 0)
-    : MCFragment(FT_Fill, SD),
-      Value(_Value), ValueSize(_ValueSize), Size(_Size) {
+  MCFillFragment(int64_t Value, unsigned ValueSize, uint64_t Size,
+                 MCSectionData *SD = nullptr)
+      : MCFragment(FT_Fill, SD), Value(Value), ValueSize(ValueSize),
+        Size(Size) {
     assert((!ValueSize || (Size % ValueSize) == 0) &&
            "Fill size must be a multiple of the value size!");
   }
 
-  /// @name Accessors
+  /// \name Accessors
   /// @{
 
   int64_t getValue() const { return Value; }
@@ -296,10 +399,11 @@ public:
   static bool classof(const MCFragment *F) {
     return F->getKind() == MCFragment::FT_Fill;
   }
-  static bool classof(const MCFillFragment *) { return true; }
 };
 
 class MCOrgFragment : public MCFragment {
+  virtual void anchor();
+
   /// Offset - The offset this fragment should start at.
   const MCExpr *Offset;
 
@@ -307,11 +411,10 @@ class MCOrgFragment : public MCFragment {
   int8_t Value;
 
 public:
-  MCOrgFragment(const MCExpr &_Offset, int8_t _Value, MCSectionData *SD = 0)
-    : MCFragment(FT_Org, SD),
-      Offset(&_Offset), Value(_Value) {}
+  MCOrgFragment(const MCExpr &Offset, int8_t Value, MCSectionData *SD = nullptr)
+      : MCFragment(FT_Org, SD), Offset(&Offset), Value(Value) {}
 
-  /// @name Accessors
+  /// \name Accessors
   /// @{
 
   const MCExpr &getOffset() const { return *Offset; }
@@ -323,10 +426,11 @@ public:
   static bool classof(const MCFragment *F) {
     return F->getKind() == MCFragment::FT_Org;
   }
-  static bool classof(const MCOrgFragment *) { return true; }
 };
 
 class MCLEBFragment : public MCFragment {
+  virtual void anchor();
+
   /// Value - The value this fragment should contain.
   const MCExpr *Value;
 
@@ -334,12 +438,15 @@ class MCLEBFragment : public MCFragment {
   bool IsSigned;
 
   SmallString<8> Contents;
+
 public:
-  MCLEBFragment(const MCExpr &Value_, bool IsSigned_, MCSectionData *SD)
-    : MCFragment(FT_LEB, SD),
-      Value(&Value_), IsSigned(IsSigned_) { Contents.push_back(0); }
+  MCLEBFragment(const MCExpr &Value_, bool IsSigned_,
+                MCSectionData *SD = nullptr)
+      : MCFragment(FT_LEB, SD), Value(&Value_), IsSigned(IsSigned_) {
+    Contents.push_back(0);
+  }
 
-  /// @name Accessors
+  /// \name Accessors
   /// @{
 
   const MCExpr &getValue() const { return *Value; }
@@ -354,10 +461,11 @@ public:
   static bool classof(const MCFragment *F) {
     return F->getKind() == MCFragment::FT_LEB;
   }
-  static bool classof(const MCLEBFragment *) { return true; }
 };
 
 class MCDwarfLineAddrFragment : public MCFragment {
+  virtual void anchor();
+
   /// LineDelta - the value of the difference between the two line numbers
   /// between two .loc dwarf directives.
   int64_t LineDelta;
@@ -369,12 +477,13 @@ class MCDwarfLineAddrFragment : public MCFragment {
   SmallString<8> Contents;
 
 public:
-  MCDwarfLineAddrFragment(int64_t _LineDelta, const MCExpr &_AddrDelta,
-                      MCSectionData *SD)
-    : MCFragment(FT_Dwarf, SD),
-      LineDelta(_LineDelta), AddrDelta(&_AddrDelta) { Contents.push_back(0); }
+  MCDwarfLineAddrFragment(int64_t LineDelta, const MCExpr &AddrDelta,
+                          MCSectionData *SD = nullptr)
+      : MCFragment(FT_Dwarf, SD), LineDelta(LineDelta), AddrDelta(&AddrDelta) {
+    Contents.push_back(0);
+  }
 
-  /// @name Accessors
+  /// \name Accessors
   /// @{
 
   int64_t getLineDelta() const { return LineDelta; }
@@ -389,10 +498,11 @@ public:
   static bool classof(const MCFragment *F) {
     return F->getKind() == MCFragment::FT_Dwarf;
   }
-  static bool classof(const MCDwarfLineAddrFragment *) { return true; }
 };
 
 class MCDwarfCallFrameFragment : public MCFragment {
+  virtual void anchor();
+
   /// AddrDelta - The expression for the difference of the two symbols that
   /// make up the address delta between two .cfi_* dwarf directives.
   const MCExpr *AddrDelta;
@@ -400,11 +510,12 @@ class MCDwarfCallFrameFragment : public MCFragment {
   SmallString<8> Contents;
 
 public:
-  MCDwarfCallFrameFragment(const MCExpr &_AddrDelta,  MCSectionData *SD)
-    : MCFragment(FT_DwarfFrame, SD),
-      AddrDelta(&_AddrDelta) { Contents.push_back(0); }
+  MCDwarfCallFrameFragment(const MCExpr &AddrDelta, MCSectionData *SD = nullptr)
+      : MCFragment(FT_DwarfFrame, SD), AddrDelta(&AddrDelta) {
+    Contents.push_back(0);
+  }
 
-  /// @name Accessors
+  /// \name Accessors
   /// @{
 
   const MCExpr &getAddrDelta() const { return *AddrDelta; }
@@ -417,7 +528,6 @@ public:
   static bool classof(const MCFragment *F) {
     return F->getKind() == MCFragment::FT_DwarfFrame;
   }
-  static bool classof(const MCDwarfCallFrameFragment *) { return true; }
 };
 
 // FIXME: Should this be a separate class, or just merged into MCSection? Since
@@ -426,8 +536,8 @@ public:
 class MCSectionData : public ilist_node<MCSectionData> {
   friend class MCAsmLayout;
 
-  MCSectionData(const MCSectionData&);  // DO NOT IMPLEMENT
-  void operator=(const MCSectionData&); // DO NOT IMPLEMENT
+  MCSectionData(const MCSectionData &) = delete;
+  void operator=(const MCSectionData &) = delete;
 
 public:
   typedef iplist<MCFragment> FragmentListType;
@@ -438,9 +548,16 @@ public:
   typedef FragmentListType::const_reverse_iterator const_reverse_iterator;
   typedef FragmentListType::reverse_iterator reverse_iterator;
 
+  /// \brief Express the state of bundle locked groups while emitting code.
+  enum BundleLockStateType {
+    NotBundleLocked,
+    BundleLocked,
+    BundleLockedAlignToEnd
+  };
+
 private:
   FragmentListType Fragments;
-  const MCSection *Section;
+  MCSection *Section;
 
   /// Ordinal - The section index in the assemblers section list.
   unsigned Ordinal;
@@ -448,10 +565,17 @@ private:
   /// LayoutOrder - The index of this section in the layout order.
   unsigned LayoutOrder;
 
-  /// Alignment - The maximum alignment seen in this section.
-  unsigned Alignment;
+  /// \brief Keeping track of bundle-locked state.
+  BundleLockStateType BundleLockState;
 
-  /// @name Assembler Backend Data
+  /// \brief Current nesting depth of bundle_lock directives.
+  unsigned BundleLockNestingDepth;
+
+  /// \brief We've seen a bundle_lock directive but not its first instruction
+  /// yet.
+  bool BundleGroupBeforeFirstInst;
+
+  /// \name Assembler Backend Data
   /// @{
   //
   // FIXME: This could all be kept private to the assembler implementation.
@@ -460,17 +584,21 @@ private:
   /// it.
   unsigned HasInstructions : 1;
 
+  /// Mapping from subsection number to insertion point for subsection numbers
+  /// below that number.
+  SmallVector<std::pair<unsigned, MCFragment *>, 1> SubsectionFragmentMap;
+
   /// @}
 
 public:
   // Only for use as sentinel.
   MCSectionData();
-  MCSectionData(const MCSection &Section, MCAssembler *A = 0);
+  MCSectionData(MCSection &Section, MCAssembler *A = nullptr);
 
-  const MCSection &getSection() const { return *Section; }
+  MCSection &getSection() const { return *Section; }
 
-  unsigned getAlignment() const { return Alignment; }
-  void setAlignment(unsigned Value) { Alignment = Value; }
+  unsigned getAlignment() const;
+  void setAlignment(unsigned Value);
 
   bool hasInstructions() const { return HasInstructions; }
   void setHasInstructions(bool Value) { HasInstructions = Value; }
@@ -481,7 +609,7 @@ public:
   unsigned getLayoutOrder() const { return LayoutOrder; }
   void setLayoutOrder(unsigned Value) { LayoutOrder = Value; }
 
-  /// @name Fragment Access
+  /// \name Fragment Access
   /// @{
 
   const FragmentListType &getFragmentList() const { return Fragments; }
@@ -503,132 +631,25 @@ public:
 
   bool empty() const { return Fragments.empty(); }
 
-  void dump();
-
-  /// @}
-};
-
-// FIXME: Same concerns as with SectionData.
-class MCSymbolData : public ilist_node<MCSymbolData> {
-public:
-  const MCSymbol *Symbol;
-
-  /// Fragment - The fragment this symbol's value is relative to, if any.
-  MCFragment *Fragment;
+  iterator getSubsectionInsertionPoint(unsigned Subsection);
 
-  /// Offset - The offset to apply to the fragment address to form this symbol's
-  /// value.
-  uint64_t Offset;
+  bool isBundleLocked() const { return BundleLockState != NotBundleLocked; }
 
-  /// IsExternal - True if this symbol is visible outside this translation
-  /// unit.
-  unsigned IsExternal : 1;
+  BundleLockStateType getBundleLockState() const { return BundleLockState; }
 
-  /// IsPrivateExtern - True if this symbol is private extern.
-  unsigned IsPrivateExtern : 1;
+  void setBundleLockState(BundleLockStateType NewState);
 
-  /// CommonSize - The size of the symbol, if it is 'common', or 0.
-  //
-  // FIXME: Pack this in with other fields? We could put it in offset, since a
-  // common symbol can never get a definition.
-  uint64_t CommonSize;
-
-  /// SymbolSize - An expression describing how to calculate the size of
-  /// a symbol. If a symbol has no size this field will be NULL.
-  const MCExpr *SymbolSize;
-
-  /// CommonAlign - The alignment of the symbol, if it is 'common'.
-  //
-  // FIXME: Pack this in with other fields?
-  unsigned CommonAlign;
-
-  /// Flags - The Flags field is used by object file implementations to store
-  /// additional per symbol information which is not easily classified.
-  uint32_t Flags;
-
-  /// Index - Index field, for use by the object file implementation.
-  uint64_t Index;
-
-public:
-  // Only for use as sentinel.
-  MCSymbolData();
-  MCSymbolData(const MCSymbol &_Symbol, MCFragment *_Fragment, uint64_t _Offset,
-               MCAssembler *A = 0);
-
-  /// @name Accessors
-  /// @{
-
-  const MCSymbol &getSymbol() const { return *Symbol; }
-
-  MCFragment *getFragment() const { return Fragment; }
-  void setFragment(MCFragment *Value) { Fragment = Value; }
-
-  uint64_t getOffset() const { return Offset; }
-  void setOffset(uint64_t Value) { Offset = Value; }
-
-  /// @}
-  /// @name Symbol Attributes
-  /// @{
-
-  bool isExternal() const { return IsExternal; }
-  void setExternal(bool Value) { IsExternal = Value; }
-
-  bool isPrivateExtern() const { return IsPrivateExtern; }
-  void setPrivateExtern(bool Value) { IsPrivateExtern = Value; }
-
-  /// isCommon - Is this a 'common' symbol.
-  bool isCommon() const { return CommonSize != 0; }
-
-  /// setCommon - Mark this symbol as being 'common'.
-  ///
-  /// \param Size - The size of the symbol.
-  /// \param Align - The alignment of the symbol.
-  void setCommon(uint64_t Size, unsigned Align) {
-    CommonSize = Size;
-    CommonAlign = Align;
-  }
-
-  /// getCommonSize - Return the size of a 'common' symbol.
-  uint64_t getCommonSize() const {
-    assert(isCommon() && "Not a 'common' symbol!");
-    return CommonSize;
-  }
-
-  void setSize(const MCExpr *SS) {
-    SymbolSize = SS;
-  }
-
-  const MCExpr *getSize() const {
-    return SymbolSize;
-  }
-
-
-  /// getCommonAlignment - Return the alignment of a 'common' symbol.
-  unsigned getCommonAlignment() const {
-    assert(isCommon() && "Not a 'common' symbol!");
-    return CommonAlign;
+  bool isBundleGroupBeforeFirstInst() const {
+    return BundleGroupBeforeFirstInst;
   }
 
-  /// getFlags - Get the (implementation defined) symbol flags.
-  uint32_t getFlags() const { return Flags; }
-
-  /// setFlags - Set the (implementation defined) symbol flags.
-  void setFlags(uint32_t Value) { Flags = Value; }
-
-  /// modifyFlags - Modify the flags via a mask
-  void modifyFlags(uint32_t Value, uint32_t Mask) {
-    Flags = (Flags & ~Mask) | Value;
+  void setBundleGroupBeforeFirstInst(bool IsFirst) {
+    BundleGroupBeforeFirstInst = IsFirst;
   }
 
-  /// getIndex - Get the (implementation defined) index.
-  uint64_t getIndex() const { return Index; }
-
-  /// setIndex - Set the (implementation defined) index.
-  void setIndex(uint64_t Value) { Index = Value; }
+  void dump();
 
   /// @}
-
-  void dump();
 };
 
 // FIXME: This really doesn't belong here. See comments below.
@@ -637,30 +658,61 @@ struct IndirectSymbolData {
   MCSectionData *SectionData;
 };
 
+// FIXME: Ditto this. Purely so the Streamer and the ObjectWriter can talk
+// to one another.
+struct DataRegionData {
+  // This enum should be kept in sync w/ the mach-o definition in
+  // llvm/Object/MachOFormat.h.
+  enum KindTy { Data = 1, JumpTable8, JumpTable16, JumpTable32 } Kind;
+  MCSymbol *Start;
+  MCSymbol *End;
+};
+
 class MCAssembler {
   friend class MCAsmLayout;
 
 public:
   typedef iplist<MCSectionData> SectionDataListType;
-  typedef iplist<MCSymbolData> SymbolDataListType;
+  typedef std::vector<const MCSymbol *> SymbolDataListType;
 
   typedef SectionDataListType::const_iterator const_iterator;
   typedef SectionDataListType::iterator iterator;
 
-  typedef SymbolDataListType::const_iterator const_symbol_iterator;
-  typedef SymbolDataListType::iterator symbol_iterator;
+  typedef pointee_iterator<SymbolDataListType::const_iterator>
+  const_symbol_iterator;
+  typedef pointee_iterator<SymbolDataListType::iterator> symbol_iterator;
+
+  typedef iterator_range<symbol_iterator> symbol_range;
+  typedef iterator_range<const_symbol_iterator> const_symbol_range;
+
+  typedef std::vector<std::string> FileNameVectorType;
+  typedef FileNameVectorType::const_iterator const_file_name_iterator;
 
   typedef std::vector<IndirectSymbolData>::const_iterator
-    const_indirect_symbol_iterator;
+      const_indirect_symbol_iterator;
   typedef std::vector<IndirectSymbolData>::iterator indirect_symbol_iterator;
 
+  typedef std::vector<DataRegionData>::const_iterator
+      const_data_region_iterator;
+  typedef std::vector<DataRegionData>::iterator data_region_iterator;
+
+  /// MachO specific deployment target version info.
+  // A Major version of 0 indicates that no version information was supplied
+  // and so the corresponding load command should not be emitted.
+  typedef struct {
+    MCVersionMinType Kind;
+    unsigned Major;
+    unsigned Minor;
+    unsigned Update;
+  } VersionMinInfoType;
+
 private:
-  MCAssembler(const MCAssembler&);    // DO NOT IMPLEMENT
-  void operator=(const MCAssembler&); // DO NOT IMPLEMENT
+  MCAssembler(const MCAssembler &) = delete;
+  void operator=(const MCAssembler &) = delete;
 
   MCContext &Context;
 
-  TargetAsmBackend &Backend;
+  MCAsmBackend &Backend;
 
   MCCodeEmitter &Emitter;
 
@@ -670,20 +722,25 @@ private:
 
   iplist<MCSectionData> Sections;
 
-  iplist<MCSymbolData> Symbols;
+  SymbolDataListType Symbols;
 
-  /// The map of sections to their associated assembler backend data.
-  //
-  // FIXME: Avoid this indirection?
-  DenseMap<const MCSection*, MCSectionData*> SectionMap;
+  DenseSet<const MCSymbol *> LocalsUsedInReloc;
 
-  /// The map of symbols to their associated assembler backend data.
+  /// The map of sections to their associated assembler backend data.
   //
   // FIXME: Avoid this indirection?
-  DenseMap<const MCSymbol*, MCSymbolData*> SymbolMap;
+  DenseMap<const MCSection *, MCSectionData *> SectionMap;
 
   std::vector<IndirectSymbolData> IndirectSymbols;
 
+  std::vector<DataRegionData> DataRegions;
+
+  /// The list of linker options to propagate into the object file.
+  std::vector<std::vector<std::string>> LinkerOptions;
+
+  /// List of declared file names
+  FileNameVectorType FileNames;
+
   /// The set of function symbols for which a .thumb_func directive has
   /// been seen.
   //
@@ -691,12 +748,29 @@ private:
   // here. Maybe when the relocation stuff moves to target specific,
   // this can go with it? The streamer would need some target specific
   // refactoring too.
-  SmallPtrSet<const MCSymbol*, 64> ThumbFuncs;
+  mutable SmallPtrSet<const MCSymbol *, 64> ThumbFuncs;
+
+  /// \brief The bundle alignment size currently set in the assembler.
+  ///
+  /// By default it's 0, which means bundling is disabled.
+  unsigned BundleAlignSize;
 
   unsigned RelaxAll : 1;
-  unsigned NoExecStack : 1;
   unsigned SubsectionsViaSymbols : 1;
 
+  /// ELF specific e_header flags
+  // It would be good if there were an MCELFAssembler class to hold this.
+  // ELF header flags are used both by the integrated and standalone assemblers.
+  // Access to the flags is necessary in cases where assembler directives affect
+  // which flags to be set.
+  unsigned ELFHeaderEFlags;
+
+  /// Used to communicate Linker Optimization Hint information between
+  /// the Streamer and the .o writer
+  MCLOHContainer LOHContainer;
+
+  VersionMinInfoType VersionMinInfo;
+
 private:
   /// Evaluate a fixup to a relocatable expression and the value which should be
   /// placed into the fixup.
@@ -709,49 +783,55 @@ private:
   /// \param Value [out] On return, the value of the fixup as currently laid
   /// out.
   /// \return Whether the fixup value was fully resolved. This is true if the
-  /// \arg Value result is fixed, otherwise the value may change due to
+  /// \p Value result is fixed, otherwise the value may change due to
   /// relocation.
-  bool EvaluateFixup(const MCAsmLayout &Layout,
-                     const MCFixup &Fixup, const MCFragment *DF,
-                     MCValue &Target, uint64_t &Value) const;
+  bool evaluateFixup(const MCAsmLayout &Layout, const MCFixup &Fixup,
+                     const MCFragment *DF, MCValue &Target,
+                     uint64_t &Value) const;
 
   /// Check whether a fixup can be satisfied, or whether it needs to be relaxed
   /// (increased in size, in order to hold its value correctly).
-  bool FixupNeedsRelaxation(const MCFixup &Fixup, const MCFragment *DF,
+  bool fixupNeedsRelaxation(const MCFixup &Fixup, const MCRelaxableFragment *DF,
                             const MCAsmLayout &Layout) const;
 
   /// Check whether the given fragment needs relaxation.
-  bool FragmentNeedsRelaxation(const MCInstFragment *IF,
+  bool fragmentNeedsRelaxation(const MCRelaxableFragment *IF,
                                const MCAsmLayout &Layout) const;
 
-  /// LayoutOnce - Perform one layout iteration and return true if any offsets
+  /// \brief Perform one layout iteration and return true if any offsets
   /// were adjusted.
-  bool LayoutOnce(MCAsmLayout &Layout);
+  bool layoutOnce(MCAsmLayout &Layout);
 
-  bool LayoutSectionOnce(MCAsmLayout &Layout, MCSectionData &SD);
+  /// \brief Perform one layout iteration of the given section and return true
+  /// if any offsets were adjusted.
+  bool layoutSectionOnce(MCAsmLayout &Layout, MCSectionData &SD);
 
-  bool RelaxInstruction(MCAsmLayout &Layout, MCInstFragment &IF);
+  bool relaxInstruction(MCAsmLayout &Layout, MCRelaxableFragment &IF);
 
-  bool RelaxLEB(MCAsmLayout &Layout, MCLEBFragment &IF);
+  bool relaxLEB(MCAsmLayout &Layout, MCLEBFragment &IF);
 
-  bool RelaxDwarfLineAddr(MCAsmLayout &Layout, MCDwarfLineAddrFragment &DF);
-  bool RelaxDwarfCallFrameFragment(MCAsmLayout &Layout,
+  bool relaxDwarfLineAddr(MCAsmLayout &Layout, MCDwarfLineAddrFragment &DF);
+  bool relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
                                    MCDwarfCallFrameFragment &DF);
 
-  /// FinishLayout - Finalize a layout, including fragment lowering.
-  void FinishLayout(MCAsmLayout &Layout);
+  /// finishLayout - Finalize a layout, including fragment lowering.
+  void finishLayout(MCAsmLayout &Layout);
 
-  uint64_t HandleFixup(const MCAsmLayout &Layout,
-                       MCFragment &F, const MCFixup &Fixup);
+  std::pair<uint64_t, bool> handleFixup(const MCAsmLayout &Layout,
+                                        MCFragment &F, const MCFixup &Fixup);
 
 public:
+  void addLocalUsedInReloc(const MCSymbol &Sym);
+  bool isLocalUsedInReloc(const MCSymbol &Sym) const;
+
   /// Compute the effective fragment size assuming it is laid out at the given
-  /// \arg SectionAddress and \arg FragmentOffset.
-  uint64_t ComputeFragmentSize(const MCAsmLayout &Layout, const MCFragment &F) const;
+  /// \p SectionAddress and \p FragmentOffset.
+  uint64_t computeFragmentSize(const MCAsmLayout &Layout,
+                               const MCFragment &F) const;
 
   /// Find the symbol which defines the atom containing the given symbol, or
   /// null if there is no such symbol.
-  const MCSymbolData *getAtom(const MCSymbolData *Symbol) const;
+  const MCSymbol *getAtom(const MCSymbol &S) const;
 
   /// Check whether a particular symbol is visible to the linker and is required
   /// in the symbol table, or whether it can be discarded by the assembler. This
@@ -760,59 +840,78 @@ public:
   bool isSymbolLinkerVisible(const MCSymbol &SD) const;
 
   /// Emit the section contents using the given object writer.
-  void WriteSectionData(const MCSectionData *Section,
+  void writeSectionData(const MCSectionData *Section,
                         const MCAsmLayout &Layout) const;
 
   /// Check whether a given symbol has been flagged with .thumb_func.
-  bool isThumbFunc(const MCSymbol *Func) const {
-    return ThumbFuncs.count(Func);
-  }
+  bool isThumbFunc(const MCSymbol *Func) const;
 
   /// Flag a function symbol as the target of a .thumb_func directive.
   void setIsThumbFunc(const MCSymbol *Func) { ThumbFuncs.insert(Func); }
 
+  /// ELF e_header flags
+  unsigned getELFHeaderEFlags() const { return ELFHeaderEFlags; }
+  void setELFHeaderEFlags(unsigned Flags) { ELFHeaderEFlags = Flags; }
+
+  /// MachO deployment target version information.
+  const VersionMinInfoType &getVersionMinInfo() const { return VersionMinInfo; }
+  void setVersionMinInfo(MCVersionMinType Kind, unsigned Major, unsigned Minor,
+                         unsigned Update) {
+    VersionMinInfo.Kind = Kind;
+    VersionMinInfo.Major = Major;
+    VersionMinInfo.Minor = Minor;
+    VersionMinInfo.Update = Update;
+  }
+
 public:
   /// Construct a new assembler instance.
   ///
-  /// \arg OS - The stream to output to.
+  /// \param OS The stream to output to.
   //
   // FIXME: How are we going to parameterize this? Two obvious options are stay
   // concrete and require clients to pass in a target like object. The other
   // option is to make this abstract, and have targets provide concrete
   // implementations as we do with AsmParser.
-  MCAssembler(MCContext &Context_, TargetAsmBackend &Backend_,
+  MCAssembler(MCContext &Context_, MCAsmBackend &Backend_,
               MCCodeEmitter &Emitter_, MCObjectWriter &Writer_,
               raw_ostream &OS);
   ~MCAssembler();
 
+  /// Reuse an assembler instance
+  ///
+  void reset();
+
   MCContext &getContext() const { return Context; }
 
-  TargetAsmBackend &getBackend() const { return Backend; }
+  MCAsmBackend &getBackend() const { return Backend; }
 
   MCCodeEmitter &getEmitter() const { return Emitter; }
 
   MCObjectWriter &getWriter() const { return Writer; }
 
   /// Finish - Do final processing and write the object to the output stream.
-  /// \arg Writer is used for custom object writer (as the MCJIT does),
+  /// \p Writer is used for custom object writer (as the MCJIT does),
   /// if not specified it is automatically created from backend.
   void Finish();
 
   // FIXME: This does not belong here.
-  bool getSubsectionsViaSymbols() const {
-    return SubsectionsViaSymbols;
-  }
-  void setSubsectionsViaSymbols(bool Value) {
-    SubsectionsViaSymbols = Value;
-  }
+  bool getSubsectionsViaSymbols() const { return SubsectionsViaSymbols; }
+  void setSubsectionsViaSymbols(bool Value) { SubsectionsViaSymbols = Value; }
 
   bool getRelaxAll() const { return RelaxAll; }
   void setRelaxAll(bool Value) { RelaxAll = Value; }
 
-  bool getNoExecStack() const { return NoExecStack; }
-  void setNoExecStack(bool Value) { NoExecStack = Value; }
+  bool isBundlingEnabled() const { return BundleAlignSize != 0; }
+
+  unsigned getBundleAlignSize() const { return BundleAlignSize; }
 
-  /// @name Section List Access
+  void setBundleAlignSize(unsigned Size) {
+    assert((Size == 0 || !(Size & (Size - 1))) &&
+           "Expect a power-of-two bundle align size");
+    BundleAlignSize = Size;
+  }
+
+  /// \name Section List Access
   /// @{
 
   const SectionDataListType &getSectionList() const { return Sections; }
@@ -827,22 +926,23 @@ public:
   size_t size() const { return Sections.size(); }
 
   /// @}
-  /// @name Symbol List Access
+  /// \name Symbol List Access
   /// @{
-
-  const SymbolDataListType &getSymbolList() const { return Symbols; }
-  SymbolDataListType &getSymbolList() { return Symbols; }
-
   symbol_iterator symbol_begin() { return Symbols.begin(); }
   const_symbol_iterator symbol_begin() const { return Symbols.begin(); }
 
   symbol_iterator symbol_end() { return Symbols.end(); }
   const_symbol_iterator symbol_end() const { return Symbols.end(); }
 
+  symbol_range symbols() { return make_range(symbol_begin(), symbol_end()); }
+  const_symbol_range symbols() const {
+    return make_range(symbol_begin(), symbol_end());
+  }
+
   size_t symbol_size() const { return Symbols.size(); }
 
   /// @}
-  /// @name Indirect Symbol List Access
+  /// \name Indirect Symbol List Access
   /// @{
 
   // FIXME: This is a total hack, this should not be here. Once things are
@@ -869,7 +969,47 @@ public:
   size_t indirect_symbol_size() const { return IndirectSymbols.size(); }
 
   /// @}
-  /// @name Backend Data Access
+  /// \name Linker Option List Access
+  /// @{
+
+  std::vector<std::vector<std::string>> &getLinkerOptions() {
+    return LinkerOptions;
+  }
+
+  /// @}
+  /// \name Data Region List Access
+  /// @{
+
+  // FIXME: This is a total hack, this should not be here. Once things are
+  // factored so that the streamer has direct access to the .o writer, it can
+  // disappear.
+  std::vector<DataRegionData> &getDataRegions() { return DataRegions; }
+
+  data_region_iterator data_region_begin() { return DataRegions.begin(); }
+  const_data_region_iterator data_region_begin() const {
+    return DataRegions.begin();
+  }
+
+  data_region_iterator data_region_end() { return DataRegions.end(); }
+  const_data_region_iterator data_region_end() const {
+    return DataRegions.end();
+  }
+
+  size_t data_region_size() const { return DataRegions.size(); }
+
+  /// @}
+  /// \name Data Region List Access
+  /// @{
+
+  // FIXME: This is a total hack, this should not be here. Once things are
+  // factored so that the streamer has direct access to the .o writer, it can
+  // disappear.
+  MCLOHContainer &getLOHContainer() { return LOHContainer; }
+  const MCLOHContainer &getLOHContainer() const {
+    return const_cast<MCAssembler *>(this)->getLOHContainer();
+  }
+  /// @}
+  /// \name Backend Data Access
   /// @{
 
   MCSectionData &getSectionData(const MCSection &Section) const {
@@ -878,39 +1018,68 @@ public:
     return *Entry;
   }
 
-  MCSectionData &getOrCreateSectionData(const MCSection &Section,
-                                        bool *Created = 0) {
+  MCSectionData &getOrCreateSectionData(MCSection &Section,
+                                        bool *Created = nullptr) {
     MCSectionData *&Entry = SectionMap[&Section];
 
-    if (Created) *Created = !Entry;
+    if (Created)
+      *Created = !Entry;
     if (!Entry)
       Entry = new MCSectionData(Section, this);
 
     return *Entry;
   }
 
-  MCSymbolData &getSymbolData(const MCSymbol &Symbol) const {
-    MCSymbolData *Entry = SymbolMap.lookup(&Symbol);
-    assert(Entry && "Missing symbol data!");
-    return *Entry;
+  bool hasSymbolData(const MCSymbol &Symbol) const { return Symbol.hasData(); }
+
+  MCSymbolData &getSymbolData(const MCSymbol &Symbol) {
+    return const_cast<MCSymbolData &>(
+        static_cast<const MCAssembler &>(*this).getSymbolData(Symbol));
+  }
+
+  const MCSymbolData &getSymbolData(const MCSymbol &Symbol) const {
+    return Symbol.getData();
   }
 
   MCSymbolData &getOrCreateSymbolData(const MCSymbol &Symbol,
-                                      bool *Created = 0) {
-    MCSymbolData *&Entry = SymbolMap[&Symbol];
+                                      bool *Created = nullptr) {
+    if (Created)
+      *Created = !hasSymbolData(Symbol);
+    if (!hasSymbolData(Symbol)) {
+      Symbol.initializeData();
+      Symbols.push_back(&Symbol);
+    }
+    return Symbol.getData();
+  }
 
-    if (Created) *Created = !Entry;
-    if (!Entry)
-      Entry = new MCSymbolData(Symbol, 0, 0, this);
+  const_file_name_iterator file_names_begin() const {
+    return FileNames.begin();
+  }
 
-    return *Entry;
+  const_file_name_iterator file_names_end() const { return FileNames.end(); }
+
+  void addFileName(StringRef FileName) {
+    if (std::find(file_names_begin(), file_names_end(), FileName) ==
+        file_names_end())
+      FileNames.push_back(FileName);
   }
 
+  /// \brief Write the necessary bundle padding to the given object writer.
+  /// Expects a fragment \p F containing instructions and its size \p FSize.
+  void writeFragmentPadding(const MCFragment &F, uint64_t FSize,
+                            MCObjectWriter *OW) const;
+
   /// @}
 
   void dump();
 };
 
+/// \brief Compute the amount of padding required before the fragment \p F to
+/// obey bundling restrictions, where \p FOffset is the fragment's offset in
+/// its section and \p FSize is the fragment's size.
+uint64_t computeBundlePadding(const MCAssembler &Assembler, const MCFragment *F,
+                              uint64_t FOffset, uint64_t FSize);
+
 } // end namespace llvm
 
 #endif