Update LLVM for rebase to r212749.

Includes a cherry-pick of:
r212948 - fixes a small issue with atomic calls

Change-Id: Ib97bd980b59f18142a69506400911a6009d9df18

40 files changed, 1092 insertions, 651 deletions

diff --git a/lib/MC/Android.mk b/lib/MC/Android.mk
index 23ad1d3..fd587c4 100644
--- a/lib/MC/Android.mk
+++ b/lib/MC/Android.mk
@@ -1,6 +1,7 @@
 LOCAL_PATH:= $(call my-dir)
 
 mc_SRC_FILES := \
+  ConstantPools.cpp \
   ELFObjectWriter.cpp \
   MCAsmBackend.cpp \
   MCAsmInfo.cpp \
@@ -9,7 +10,6 @@ mc_SRC_FILES := \
   MCAsmInfoELF.cpp \
   MCAsmStreamer.cpp \
   MCAssembler.cpp \
-  MCAtom.cpp \
   MCCodeEmitter.cpp \
   MCCodeGenInfo.cpp \
   MCContext.cpp \
@@ -18,7 +18,6 @@ mc_SRC_FILES := \
   MCELF.cpp \
   MCELFObjectTargetWriter.cpp \
   MCELFStreamer.cpp \
-  MCFunction.cpp \
   MCExpr.cpp \
   MCExternalSymbolizer.cpp \
   MCInst.cpp \
@@ -28,13 +27,9 @@ mc_SRC_FILES := \
   MCLinkerOptimizationHint.cpp \
   MCMachOStreamer.cpp \
   MCMachObjectTargetWriter.cpp \
-  MCModule.cpp \
-  MCModuleYAML.cpp \
   MCNullStreamer.cpp \
   MCObjectFileInfo.cpp \
-  MCObjectDisassembler.cpp \
   MCObjectStreamer.cpp \
-  MCObjectSymbolizer.cpp \
   MCObjectWriter.cpp \
   MCRegisterInfo.cpp \
   MCRelocationInfo.cpp \
@@ -50,9 +45,11 @@ mc_SRC_FILES := \
   MCValue.cpp \
   MCWin64EH.cpp \
   MachObjectWriter.cpp \
+  StringTableBuilder.cpp \
   SubtargetFeature.cpp \
   WinCOFFObjectWriter.cpp \
   WinCOFFStreamer.cpp \
+  YAML.cpp
 
 # For the host
 # =====================================================
diff --git a/lib/MC/CMakeLists.txt b/lib/MC/CMakeLists.txt
index 6a384c1..330519e 100644
--- a/lib/MC/CMakeLists.txt
+++ b/lib/MC/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_llvm_library(LLVMMC
+  ConstantPools.cpp
   ELFObjectWriter.cpp
   MCAsmBackend.cpp
   MCAsmInfo.cpp
@@ -7,7 +8,6 @@ add_llvm_library(LLVMMC
   MCAsmInfoELF.cpp
   MCAsmStreamer.cpp
   MCAssembler.cpp
-  MCAtom.cpp
   MCCodeEmitter.cpp
   MCCodeGenInfo.cpp
   MCContext.cpp
@@ -16,7 +16,6 @@ add_llvm_library(LLVMMC
   MCELF.cpp
   MCELFObjectTargetWriter.cpp
   MCELFStreamer.cpp
-  MCFunction.cpp
   MCExpr.cpp
   MCExternalSymbolizer.cpp
   MCInst.cpp
@@ -26,13 +25,9 @@ add_llvm_library(LLVMMC
   MCLinkerOptimizationHint.cpp
   MCMachOStreamer.cpp
   MCMachObjectTargetWriter.cpp
-  MCModule.cpp
-  MCModuleYAML.cpp
   MCNullStreamer.cpp
   MCObjectFileInfo.cpp
-  MCObjectDisassembler.cpp
   MCObjectStreamer.cpp
-  MCObjectSymbolizer.cpp
   MCObjectWriter.cpp
   MCRegisterInfo.cpp
   MCRelocationInfo.cpp
@@ -48,10 +43,13 @@ add_llvm_library(LLVMMC
   MCValue.cpp
   MCWin64EH.cpp
   MachObjectWriter.cpp
+  StringTableBuilder.cpp
   SubtargetFeature.cpp
   WinCOFFObjectWriter.cpp
   WinCOFFStreamer.cpp
+  YAML.cpp
   )
 
+add_subdirectory(MCAnalysis)
 add_subdirectory(MCParser)
 add_subdirectory(MCDisassembler)
diff --git a/lib/MC/ConstantPools.cpp b/lib/MC/ConstantPools.cpp
new file mode 100644
index 0000000..f979dad
--- /dev/null
+++ b/lib/MC/ConstantPools.cpp
@@ -0,0 +1,95 @@
+//===- ConstantPools.cpp - ConstantPool class --*- C++ -*---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the ConstantPool and  AssemblerConstantPools classes.
+//
+//===----------------------------------------------------------------------===//
+#include "llvm/ADT/MapVector.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/ConstantPools.h"
+
+using namespace llvm;
+//
+// ConstantPool implementation
+//
+// Emit the contents of the constant pool using the provided streamer.
+void ConstantPool::emitEntries(MCStreamer &Streamer) {
+  if (Entries.empty())
+    return;
+  Streamer.EmitCodeAlignment(4); // align to 4-byte address
+  Streamer.EmitDataRegion(MCDR_DataRegion);
+  for (EntryVecTy::const_iterator I = Entries.begin(), E = Entries.end();
+       I != E; ++I) {
+    Streamer.EmitLabel(I->first);
+    Streamer.EmitValue(I->second, 4);
+  }
+  Streamer.EmitDataRegion(MCDR_DataRegionEnd);
+  Entries.clear();
+}
+
+const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context) {
+  MCSymbol *CPEntryLabel = Context.CreateTempSymbol();
+
+  Entries.push_back(std::make_pair(CPEntryLabel, Value));
+  return MCSymbolRefExpr::Create(CPEntryLabel, Context);
+}
+
+bool ConstantPool::empty() { return Entries.empty(); }
+
+//
+// AssemblerConstantPools implementation
+//
+ConstantPool *
+AssemblerConstantPools::getConstantPool(const MCSection *Section) {
+  ConstantPoolMapTy::iterator CP = ConstantPools.find(Section);
+  if (CP == ConstantPools.end())
+    return nullptr;
+
+  return &CP->second;
+}
+
+ConstantPool &
+AssemblerConstantPools::getOrCreateConstantPool(const MCSection *Section) {
+  return ConstantPools[Section];
+}
+
+static void emitConstantPool(MCStreamer &Streamer, const MCSection *Section,
+                             ConstantPool &CP) {
+  if (!CP.empty()) {
+    Streamer.SwitchSection(Section);
+    CP.emitEntries(Streamer);
+  }
+}
+
+void AssemblerConstantPools::emitAll(MCStreamer &Streamer) {
+  // Dump contents of assembler constant pools.
+  for (ConstantPoolMapTy::iterator CPI = ConstantPools.begin(),
+                                   CPE = ConstantPools.end();
+       CPI != CPE; ++CPI) {
+    const MCSection *Section = CPI->first;
+    ConstantPool &CP = CPI->second;
+
+    emitConstantPool(Streamer, Section, CP);
+  }
+}
+
+void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {
+  const MCSection *Section = Streamer.getCurrentSection().first;
+  if (ConstantPool *CP = getConstantPool(Section)) {
+    emitConstantPool(Streamer, Section, *CP);
+  }
+}
+
+const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,
+                                               const MCExpr *Expr) {
+  const MCSection *Section = Streamer.getCurrentSection().first;
+  return getOrCreateConstantPool(Section).addEntry(Expr, Streamer.getContext());
+}
diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 0a54627..7fb9fae 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -28,7 +28,7 @@
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCValue.h"
-#include "llvm/Object/StringTableBuilder.h"
+#include "llvm/MC/StringTableBuilder.h"
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Endian.h"
@@ -1179,7 +1179,7 @@ prependCompressionHeader(uint64_t Size,
   if (Size <= Magic.size() + sizeof(Size) + CompressedContents.size())
     return false;
   if (sys::IsLittleEndianHost)
-    Size = sys::SwapByteOrder(Size);
+    sys::swapByteOrder(Size);
   CompressedContents.insert(CompressedContents.begin(),
                             Magic.size() + sizeof(Size), 0);
   std::copy(Magic.begin(), Magic.end(), CompressedContents.begin());
@@ -1565,6 +1565,7 @@ void ELFObjectWriter::WriteSection(MCAssembler &Asm,
   case ELF::SHT_X86_64_UNWIND:
   case ELF::SHT_MIPS_REGINFO:
   case ELF::SHT_MIPS_OPTIONS:
+  case ELF::SHT_MIPS_ABIFLAGS:
     // Nothing to do.
     break;
 
@@ -1574,8 +1575,7 @@ void ELFObjectWriter::WriteSection(MCAssembler &Asm,
     break;
 
   default:
-    assert(0 && "FIXME: sh_type value not supported!");
-    break;
+    llvm_unreachable("FIXME: sh_type value not supported!");
   }
 
   if (TargetObjectWriter->getEMachine() == ELF::EM_ARM &&
diff --git a/lib/MC/LLVMBuild.txt b/lib/MC/LLVMBuild.txt
index f35dbe4..3fcb50b 100644
--- a/lib/MC/LLVMBuild.txt
+++ b/lib/MC/LLVMBuild.txt
@@ -16,10 +16,10 @@
 ;===------------------------------------------------------------------------===;
 
 [common]
-subdirectories = MCDisassembler MCParser
+subdirectories = MCAnalysis MCDisassembler MCParser
 
 [component_0]
 type = Library
 name = MC
 parent = Libraries
-required_libraries = Object Support
+required_libraries = Support
diff --git a/lib/MC/MCAnalysis/Android.mk b/lib/MC/MCAnalysis/Android.mk
new file mode 100644
index 0000000..27f848a
--- /dev/null
+++ b/lib/MC/MCAnalysis/Android.mk
@@ -0,0 +1,37 @@
+LOCAL_PATH:= $(call my-dir)
+
+mc_analysis_SRC_FILES := \
+  MCAtom.cpp \
+  MCFunction.cpp \
+  MCModule.cpp \
+  MCModuleYAML.cpp \
+  MCObjectDisassembler.cpp \
+  MCObjectSymbolizer.cpp
+
+# For the host
+# =====================================================
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(mc_analysis_SRC_FILES)
+
+LOCAL_MODULE:= libLLVMMCAnalysis
+
+LOCAL_MODULE_TAGS := optional
+
+include $(LLVM_HOST_BUILD_MK)
+include $(BUILD_HOST_STATIC_LIBRARY)
+
+# For the device
+# =====================================================
+include $(CLEAR_VARS)
+ifneq (true,$(DISABLE_LLVM_DEVICE_BUILDS))
+
+LOCAL_SRC_FILES := $(mc_analysis_SRC_FILES)
+
+LOCAL_MODULE:= libLLVMMCAnalysis
+
+LOCAL_MODULE_TAGS := optional
+
+include $(LLVM_DEVICE_BUILD_MK)
+include $(BUILD_STATIC_LIBRARY)
+endif
diff --git a/lib/MC/MCAnalysis/CMakeLists.txt b/lib/MC/MCAnalysis/CMakeLists.txt
new file mode 100644
index 0000000..81eae2d
--- /dev/null
+++ b/lib/MC/MCAnalysis/CMakeLists.txt
@@ -0,0 +1,8 @@
+add_llvm_library(LLVMMCAnalysis
+ MCAtom.cpp
+ MCFunction.cpp
+ MCModule.cpp
+ MCModuleYAML.cpp
+ MCObjectDisassembler.cpp
+ MCObjectSymbolizer.cpp
+)
diff --git a/lib/MC/MCAnalysis/LLVMBuild.txt b/lib/MC/MCAnalysis/LLVMBuild.txt
new file mode 100644
index 0000000..1b58fec
--- /dev/null
+++ b/lib/MC/MCAnalysis/LLVMBuild.txt
@@ -0,0 +1,5 @@
+[component_0]
+type = Library
+name = MCAnalysis
+parent = Libraries
+required_libraries = MC Object Support
diff --git a/lib/MC/MCAtom.cpp b/lib/MC/MCAnalysis/MCAtom.cpp
index bc353cd..82056ee 100644
--- a/lib/MC/MCAtom.cpp
+++ b/lib/MC/MCAnalysis/MCAtom.cpp
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/MC/MCAtom.h"
-#include "llvm/MC/MCModule.h"
+#include "llvm/MC/MCAnalysis/MCAtom.h"
+#include "llvm/MC/MCAnalysis/MCModule.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <iterator>
 
diff --git a/lib/MC/MCFunction.cpp b/lib/MC/MCAnalysis/MCFunction.cpp
index 1ddc250..4e09d1a 100644
--- a/lib/MC/MCFunction.cpp
+++ b/lib/MC/MCAnalysis/MCFunction.cpp
@@ -7,9 +7,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/MC/MCFunction.h"
-#include "llvm/MC/MCAtom.h"
-#include "llvm/MC/MCModule.h"
+#include "llvm/MC/MCAnalysis/MCFunction.h"
+#include "llvm/MC/MCAnalysis/MCAtom.h"
+#include "llvm/MC/MCAnalysis/MCModule.h"
 #include <algorithm>
 
 using namespace llvm;
diff --git a/lib/MC/MCModule.cpp b/lib/MC/MCAnalysis/MCModule.cpp
index 3ed7356..7512299 100644
--- a/lib/MC/MCModule.cpp
+++ b/lib/MC/MCAnalysis/MCModule.cpp
@@ -7,10 +7,10 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/MC/MCAnalysis/MCModule.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/MC/MCModule.h"
-#include "llvm/MC/MCAtom.h"
-#include "llvm/MC/MCFunction.h"
+#include "llvm/MC/MCAnalysis/MCAtom.h"
+#include "llvm/MC/MCAnalysis/MCFunction.h"
 #include <algorithm>
 
 using namespace llvm;
diff --git a/lib/MC/MCModuleYAML.cpp b/lib/MC/MCAnalysis/MCModuleYAML.cpp
index f81cb14..876b06d 100644
--- a/lib/MC/MCModuleYAML.cpp
+++ b/lib/MC/MCAnalysis/MCModuleYAML.cpp
@@ -11,13 +11,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/MC/MCModuleYAML.h"
+#include "llvm/MC/MCAnalysis/MCModuleYAML.h"
 #include "llvm/ADT/StringMap.h"
-#include "llvm/MC/MCAtom.h"
-#include "llvm/MC/MCFunction.h"
+#include "llvm/MC/MCAnalysis/MCAtom.h"
+#include "llvm/MC/MCAnalysis/MCFunction.h"
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
-#include "llvm/Object/YAML.h"
+#include "llvm/MC/YAML.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/MathExtras.h"
@@ -102,7 +102,7 @@ struct Atom {
   uint64_t Size;
 
   std::vector<Inst> Insts;
-  object::yaml::BinaryRef Data;
+  yaml::BinaryRef Data;
 };
 
 struct BasicBlock {
@@ -453,7 +453,7 @@ StringRef yaml2mcmodule(std::unique_ptr<MCModule> &MCM, StringRef YamlContent,
   InstrRegInfoHolder IRI(MII, MRI);
   yaml::Input YIn(YamlContent, (void *)&IRI);
   YIn >> YAMLModule;
-  if (error_code ec = YIn.error())
+  if (std::error_code ec = YIn.error())
     return ec.message();
   StringRef err = Parser.parse(YAMLModule);
   if (!err.empty())
diff --git a/lib/MC/MCObjectDisassembler.cpp b/lib/MC/MCAnalysis/MCObjectDisassembler.cpp
index 8a258cb..0f789ff 100644
--- a/lib/MC/MCObjectDisassembler.cpp
+++ b/lib/MC/MCAnalysis/MCObjectDisassembler.cpp
@@ -13,11 +13,11 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
-#include "llvm/MC/MCAtom.h"
+#include "llvm/MC/MCAnalysis/MCAtom.h"
+#include "llvm/MC/MCAnalysis/MCFunction.h"
+#include "llvm/MC/MCAnalysis/MCModule.h"
 #include "llvm/MC/MCDisassembler.h"
-#include "llvm/MC/MCFunction.h"
 #include "llvm/MC/MCInstrAnalysis.h"
-#include "llvm/MC/MCModule.h"
 #include "llvm/MC/MCObjectSymbolizer.h"
 #include "llvm/Object/MachO.h"
 #include "llvm/Object/ObjectFile.h"
diff --git a/lib/MC/MCObjectSymbolizer.cpp b/lib/MC/MCAnalysis/MCObjectSymbolizer.cpp
index b149596..b149596 100644
--- a/lib/MC/MCObjectSymbolizer.cpp
+++ b/lib/MC/MCAnalysis/MCObjectSymbolizer.cpp
diff --git a/lib/MC/MCAnalysis/Makefile b/lib/MC/MCAnalysis/Makefile
new file mode 100644
index 0000000..add2dbd
--- /dev/null
+++ b/lib/MC/MCAnalysis/Makefile
@@ -0,0 +1,14 @@
+##===- lib/MC/MCAnalysys/Makefile --------------------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../../..
+LIBRARYNAME = LLVMMCAnalysis
+BUILD_ARCHIVE := 1
+
+include $(LEVEL)/Makefile.common
diff --git a/lib/MC/MCAsmInfo.cpp b/lib/MC/MCAsmInfo.cpp
index c0777a6..f8081ef 100644
--- a/lib/MC/MCAsmInfo.cpp
+++ b/lib/MC/MCAsmInfo.cpp
@@ -39,7 +39,7 @@ MCAsmInfo::MCAsmInfo() {
   SeparatorString = ";";
   CommentString = "#";
   LabelSuffix = ":";
-  DebugLabelSuffix = ":";
+  UseAssignmentForEHBegin = false;
   PrivateGlobalPrefix = "L";
   LinkerPrivateGlobalPrefix = "";
   InlineAsmStart = "APP";
@@ -82,6 +82,7 @@ MCAsmInfo::MCAsmInfo() {
   HasLEB128 = false;
   SupportsDebugInformation = false;
   ExceptionsType = ExceptionHandling::None;
+  WinEHEncodingType = WinEH::EncodingType::ET_Invalid;
   DwarfUsesRelocationsAcrossSections = true;
   DwarfFDESymbolsUseAbsDiff = false;
   DwarfRegNumForCFI = false;
@@ -99,7 +100,7 @@ MCAsmInfo::MCAsmInfo() {
   //   - MCAsmInfoDarwin is handling this case
   // - Generic_GCC toolchains enable the integrated assembler on a per
   //   architecture basis.
-  //   - The target subclasses for AArch64, ARM, and X86  handle these cases
+  //   - The target subclasses for AArch64, ARM, and X86 handle these cases
   UseIntegratedAssembler = false;
 
   CompressDebugSections = false;
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 7f8ae54..6973bbb 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -120,7 +120,6 @@ public:
 
   void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) override;
   void EmitLabel(MCSymbol *Symbol) override;
-  void EmitDebugLabel(MCSymbol *Symbol) override;
 
   void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
   void EmitLinkerOptions(ArrayRef<std::string> Options) override;
@@ -213,20 +212,20 @@ public:
   void EmitCFIRegister(int64_t Register1, int64_t Register2) override;
   void EmitCFIWindowSave() override;
 
-  void EmitWin64EHStartProc(const MCSymbol *Symbol) override;
-  void EmitWin64EHEndProc() override;
-  void EmitWin64EHStartChained() override;
-  void EmitWin64EHEndChained() override;
-  void EmitWin64EHHandler(const MCSymbol *Sym, bool Unwind,
-                          bool Except) override;
-  void EmitWin64EHHandlerData() override;
-  void EmitWin64EHPushReg(unsigned Register) override;
-  void EmitWin64EHSetFrame(unsigned Register, unsigned Offset) override;
-  void EmitWin64EHAllocStack(unsigned Size) override;
-  void EmitWin64EHSaveReg(unsigned Register, unsigned Offset) override;
-  void EmitWin64EHSaveXMM(unsigned Register, unsigned Offset) override;
-  void EmitWin64EHPushFrame(bool Code) override;
-  void EmitWin64EHEndProlog() override;
+  void EmitWinCFIStartProc(const MCSymbol *Symbol) override;
+  void EmitWinCFIEndProc() override;
+  void EmitWinCFIStartChained() override;
+  void EmitWinCFIEndChained() override;
+  void EmitWinCFIPushReg(unsigned Register) override;
+  void EmitWinCFISetFrame(unsigned Register, unsigned Offset) override;
+  void EmitWinCFIAllocStack(unsigned Size) override;
+  void EmitWinCFISaveReg(unsigned Register, unsigned Offset) override;
+  void EmitWinCFISaveXMM(unsigned Register, unsigned Offset) override;
+  void EmitWinCFIPushFrame(bool Code) override;
+  void EmitWinCFIEndProlog() override;
+
+  void EmitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except) override;
+  void EmitWinEHHandlerData() override;
 
   void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI) override;
 
@@ -334,14 +333,6 @@ void MCAsmStreamer::EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
-  MCStreamer::EmitDebugLabel(Symbol);
-
-  OS << *Symbol << MAI->getDebugLabelSuffix();
-  EmitEOL();
-}
-
 void MCAsmStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   switch (Flag) {
   case MCAF_SyntaxUnified:         OS << "\t.syntax unified"; break;
@@ -944,10 +935,7 @@ void MCAsmStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
 }
 
 void MCAsmStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
-  // Put a dummy non-null value in Frame.End to mark that this frame has been
-  // closed.
-  Frame.End = (MCSymbol *) 1;
-
+  MCStreamer::EmitCFIEndProcImpl(Frame);
   OS << "\t.cfi_endproc";
   EmitEOL();
 }
@@ -1061,37 +1049,37 @@ void MCAsmStreamer::EmitCFIWindowSave() {
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHStartProc(const MCSymbol *Symbol) {
-  MCStreamer::EmitWin64EHStartProc(Symbol);
+void MCAsmStreamer::EmitWinCFIStartProc(const MCSymbol *Symbol) {
+  MCStreamer::EmitWinCFIStartProc(Symbol);
 
   OS << ".seh_proc " << *Symbol;
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHEndProc() {
-  MCStreamer::EmitWin64EHEndProc();
+void MCAsmStreamer::EmitWinCFIEndProc() {
+  MCStreamer::EmitWinCFIEndProc();
 
   OS << "\t.seh_endproc";
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHStartChained() {
-  MCStreamer::EmitWin64EHStartChained();
+void MCAsmStreamer::EmitWinCFIStartChained() {
+  MCStreamer::EmitWinCFIStartChained();
 
   OS << "\t.seh_startchained";
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHEndChained() {
-  MCStreamer::EmitWin64EHEndChained();
+void MCAsmStreamer::EmitWinCFIEndChained() {
+  MCStreamer::EmitWinCFIEndChained();
 
   OS << "\t.seh_endchained";
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHHandler(const MCSymbol *Sym, bool Unwind,
-                                       bool Except) {
-  MCStreamer::EmitWin64EHHandler(Sym, Unwind, Except);
+void MCAsmStreamer::EmitWinEHHandler(const MCSymbol *Sym, bool Unwind,
+                                      bool Except) {
+  MCStreamer::EmitWinEHHandler(Sym, Unwind, Except);
 
   OS << "\t.seh_handler " << *Sym;
   if (Unwind)
@@ -1114,8 +1102,8 @@ static const MCSection *getWin64EHTableSection(StringRef suffix,
                                 SectionKind::getDataRel());
 }
 
-void MCAsmStreamer::EmitWin64EHHandlerData() {
-  MCStreamer::EmitWin64EHHandlerData();
+void MCAsmStreamer::EmitWinEHHandlerData() {
+  MCStreamer::EmitWinEHHandlerData();
 
   // Switch sections. Don't call SwitchSection directly, because that will
   // cause the section switch to be visible in the emitted assembly.
@@ -1131,50 +1119,43 @@ void MCAsmStreamer::EmitWin64EHHandlerData() {
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHPushReg(unsigned Register) {
-  MCStreamer::EmitWin64EHPushReg(Register);
+void MCAsmStreamer::EmitWinCFIPushReg(unsigned Register) {
+  MCStreamer::EmitWinCFIPushReg(Register);
 
-  OS << "\t.seh_pushreg ";
-  EmitRegisterName(Register);
+  OS << "\t.seh_pushreg " << Register;
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHSetFrame(unsigned Register, unsigned Offset) {
-  MCStreamer::EmitWin64EHSetFrame(Register, Offset);
+void MCAsmStreamer::EmitWinCFISetFrame(unsigned Register, unsigned Offset) {
+  MCStreamer::EmitWinCFISetFrame(Register, Offset);
 
-  OS << "\t.seh_setframe ";
-  EmitRegisterName(Register);
-  OS << ", " << Offset;
+  OS << "\t.seh_setframe " << Register << ", " << Offset;
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHAllocStack(unsigned Size) {
-  MCStreamer::EmitWin64EHAllocStack(Size);
+void MCAsmStreamer::EmitWinCFIAllocStack(unsigned Size) {
+  MCStreamer::EmitWinCFIAllocStack(Size);
 
   OS << "\t.seh_stackalloc " << Size;
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHSaveReg(unsigned Register, unsigned Offset) {
-  MCStreamer::EmitWin64EHSaveReg(Register, Offset);
+void MCAsmStreamer::EmitWinCFISaveReg(unsigned Register, unsigned Offset) {
+  MCStreamer::EmitWinCFISaveReg(Register, Offset);
 
-  OS << "\t.seh_savereg ";
-  EmitRegisterName(Register);
-  OS << ", " << Offset;
+  OS << "\t.seh_savereg " << Register << ", " << Offset;
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHSaveXMM(unsigned Register, unsigned Offset) {
-  MCStreamer::EmitWin64EHSaveXMM(Register, Offset);
+void MCAsmStreamer::EmitWinCFISaveXMM(unsigned Register, unsigned Offset) {
+  MCStreamer::EmitWinCFISaveXMM(Register, Offset);
 
-  OS << "\t.seh_savexmm ";
-  EmitRegisterName(Register);
-  OS << ", " << Offset;
+  OS << "\t.seh_savexmm " << Register << ", " << Offset;
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHPushFrame(bool Code) {
-  MCStreamer::EmitWin64EHPushFrame(Code);
+void MCAsmStreamer::EmitWinCFIPushFrame(bool Code) {
+  MCStreamer::EmitWinCFIPushFrame(Code);
 
   OS << "\t.seh_pushframe";
   if (Code)
@@ -1182,8 +1163,8 @@ void MCAsmStreamer::EmitWin64EHPushFrame(bool Code) {
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitWin64EHEndProlog(void) {
-  MCStreamer::EmitWin64EHEndProlog();
+void MCAsmStreamer::EmitWinCFIEndProlog(void) {
+  MCStreamer::EmitWinCFIEndProlog();
 
   OS << "\t.seh_endprologue";
   EmitEOL();
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index 886a5f5..a8aad71 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/MC/MCSectionELF.h"
 #include <tuple>
 using namespace llvm;
 
@@ -433,12 +434,27 @@ const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
   return SD->getFragment()->getAtom();
 }
 
+// Try to fully compute Expr to an absolute value and if that fails produce
+// a relocatable expr.
+// FIXME: Should this be the behavior of EvaluateAsRelocatable itself?
+static bool evaluate(const MCExpr &Expr, const MCAsmLayout &Layout,
+                     MCValue &Target) {
+  if (Expr.EvaluateAsValue(Target, &Layout))
+    if (Target.isAbsolute())
+      return true;
+  return Expr.EvaluateAsRelocatable(Target, &Layout);
+}
+
 bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
                                 const MCFixup &Fixup, const MCFragment *DF,
                                 MCValue &Target, uint64_t &Value) const {
   ++stats::evaluateFixup;
 
-  if (!Fixup.getValue()->EvaluateAsRelocatable(Target, &Layout))
+  // FIXME: This code has some duplication with RecordRelocation. We should
+  // probably merge the two into a single callback that tries to evaluate a
+  // fixup and records a relocation if one is needed.
+  const MCExpr *Expr = Fixup.getValue();
+  if (!evaluate(*Expr, Layout, Target))
     getContext().FatalError(Fixup.getLoc(), "expected relocatable expression");
 
   bool IsPCRel = Backend.getFixupKindInfo(
@@ -782,8 +798,13 @@ void MCAssembler::writeSectionData(const MCSectionData *SD,
         assert(DF.fixup_begin() == DF.fixup_end() &&
                "Cannot have fixups in virtual section!");
         for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
-          assert(DF.getContents()[i] == 0 &&
-                 "Invalid data value for virtual section!");
+          if (DF.getContents()[i]) {
+            if (auto *ELFSec = dyn_cast<const MCSectionELF>(&SD->getSection()))
+              report_fatal_error("non-zero initializer found in section '" +
+                  ELFSec->getSectionName() + "'");
+            else
+              report_fatal_error("non-zero initializer found in virtual section");
+          }
         break;
       }
       case MCFragment::FT_Align:
@@ -1222,7 +1243,7 @@ void MCSectionData::dump() {
   OS << "]>";
 }
 
-void MCSymbolData::dump() {
+void MCSymbolData::dump() const {
   raw_ostream &OS = llvm::errs();
 
   OS << "<MCSymbolData Symbol:" << getSymbol()
diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index c163268..960a071 100644
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -39,7 +39,7 @@ MCContext::MCContext(const MCAsmInfo *mai, const MCRegisterInfo *mri,
       AllowTemporaryLabels(true), DwarfCompileUnitID(0),
       AutoReset(DoAutoReset) {
 
-  error_code EC = llvm::sys::fs::current_path(CompilationDir);
+  std::error_code EC = llvm::sys::fs::current_path(CompilationDir);
   if (EC)
     CompilationDir.clear();
 
@@ -47,8 +47,9 @@ MCContext::MCContext(const MCAsmInfo *mai, const MCRegisterInfo *mri,
   SecureLog = nullptr;
   SecureLogUsed = false;
 
-  if (SrcMgr && SrcMgr->getNumBuffers() > 0)
-    MainFileName = SrcMgr->getMemoryBuffer(0)->getBufferIdentifier();
+  if (SrcMgr && SrcMgr->getNumBuffers())
+    MainFileName =
+        SrcMgr->getMemoryBuffer(SrcMgr->getMainFileID())->getBufferIdentifier();
 }
 
 MCContext::~MCContext() {
@@ -277,14 +278,15 @@ const MCSectionELF *MCContext::CreateELFGroupSection() {
   return Result;
 }
 
-const MCSectionCOFF *
-MCContext::getCOFFSection(StringRef Section, unsigned Characteristics,
-                          SectionKind Kind, StringRef COMDATSymName,
-                          int Selection, const MCSectionCOFF *Assoc) {
+const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
+                                               unsigned Characteristics,
+                                               SectionKind Kind,
+                                               StringRef COMDATSymName,
+                                               int Selection) {
   // Do the lookup, if we have a hit, return it.
 
-  SectionGroupPair P(Section, COMDATSymName);
-  auto IterBool = COFFUniquingMap.insert(std::make_pair(P, nullptr));
+  SectionGroupTriple T(Section, COMDATSymName, Selection);
+  auto IterBool = COFFUniquingMap.insert(std::make_pair(T, nullptr));
   auto Iter = IterBool.first;
   if (!IterBool.second)
     return Iter->second;
@@ -293,9 +295,9 @@ MCContext::getCOFFSection(StringRef Section, unsigned Characteristics,
   if (!COMDATSymName.empty())
     COMDATSymbol = GetOrCreateSymbol(COMDATSymName);
 
-  StringRef CachedName = Iter->first.first;
-  MCSectionCOFF *Result = new (*this) MCSectionCOFF(
-      CachedName, Characteristics, COMDATSymbol, Selection, Assoc, Kind);
+  StringRef CachedName = std::get<0>(Iter->first);
+  MCSectionCOFF *Result = new (*this)
+      MCSectionCOFF(CachedName, Characteristics, COMDATSymbol, Selection, Kind);
 
   Iter->second = Result;
   return Result;
@@ -308,8 +310,8 @@ MCContext::getCOFFSection(StringRef Section, unsigned Characteristics,
 }
 
 const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section) {
-  SectionGroupPair P(Section, "");
-  auto Iter = COFFUniquingMap.find(P);
+  SectionGroupTriple T(Section, "", 0);
+  auto Iter = COFFUniquingMap.find(T);
   if (Iter == COFFUniquingMap.end())
     return nullptr;
   return Iter->second;
@@ -339,6 +341,29 @@ bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
   return !MCDwarfFiles[FileNumber].Name.empty();
 }
 
+/// finalizeDwarfSections - Emit end symbols for each non-empty code section.
+/// Also remove empty sections from SectionStartEndSyms, to avoid generating
+/// useless debug info for them.
+void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
+  MCContext &context = MCOS.getContext();
+
+  auto sec = SectionStartEndSyms.begin();
+  while (sec != SectionStartEndSyms.end()) {
+    assert(sec->second.first && "Start symbol must be set by now");
+    MCOS.SwitchSection(sec->first);
+    if (MCOS.mayHaveInstructions()) {
+      MCSymbol *SectionEndSym = context.CreateTempSymbol();
+      MCOS.EmitLabel(SectionEndSym);
+      sec->second.second = SectionEndSym;
+      ++sec;
+    } else {
+      MapVector<const MCSection *, std::pair<MCSymbol *, MCSymbol *> >::iterator
+        to_erase = sec;
+      sec = SectionStartEndSyms.erase(to_erase);
+    }
+  }
+}
+
 void MCContext::FatalError(SMLoc Loc, const Twine &Msg) const {
   // If we have a source manager and a location, use it. Otherwise just
   // use the generic report_fatal_error().
diff --git a/lib/MC/MCDwarf.cpp b/lib/MC/MCDwarf.cpp
index be6731a..0a3fab8 100644
--- a/lib/MC/MCDwarf.cpp
+++ b/lib/MC/MCDwarf.cpp
@@ -19,6 +19,7 @@
 #include "llvm/MC/MCObjectFileInfo.h"
 #include "llvm/MC/MCObjectStreamer.h"
 #include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSection.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -518,8 +519,12 @@ static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
   MCOS->EmitULEB128IntValue(dwarf::DW_TAG_compile_unit);
   MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
   EmitAbbrev(MCOS, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4);
-  EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
-  EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
+  if (MCOS->getContext().getGenDwarfSectionSyms().size() > 1) {
+    EmitAbbrev(MCOS, dwarf::DW_AT_ranges, dwarf::DW_FORM_data4);
+  } else {
+    EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
+    EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
+  }
   EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
   if (!context.getCompilationDir().empty())
     EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
@@ -552,20 +557,14 @@ static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
 }
 
 // When generating dwarf for assembly source files this emits the data for
-// .debug_aranges section.  Which contains a header and a table of pairs of
-// PointerSize'ed values for the address and size of section(s) with line table
-// entries (just the default .text in our case) and a terminating pair of zeros.
+// .debug_aranges section. This section contains a header and a table of pairs
+// of PointerSize'ed values for the address and size of section(s) with line
+// table entries.
 static void EmitGenDwarfAranges(MCStreamer *MCOS,
                                 const MCSymbol *InfoSectionSymbol) {
   MCContext &context = MCOS->getContext();
 
-  // Create a symbol at the end of the section that we are creating the dwarf
-  // debugging info to use later in here as part of the expression to calculate
-  // the size of the section for the table.
-  MCOS->SwitchSection(context.getGenDwarfSection());
-  MCSymbol *SectionEndSym = context.CreateTempSymbol();
-  MCOS->EmitLabel(SectionEndSym);
-  context.setGenDwarfSectionEndSym(SectionEndSym);
+  auto &Sections = context.getGenDwarfSectionSyms();
 
   MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
 
@@ -583,8 +582,8 @@ static void EmitGenDwarfAranges(MCStreamer *MCOS,
   Length += Pad;
 
   // Add the size of the pair of PointerSize'ed values for the address and size
-  // of the one default .text section we have in the table.
-  Length += 2 * AddrSize;
+  // of each section we have in the table.
+  Length += 2 * AddrSize * Sections.size();
   // And the pair of terminating zeros.
   Length += 2 * AddrSize;
 
@@ -608,14 +607,21 @@ static void EmitGenDwarfAranges(MCStreamer *MCOS,
   for(int i = 0; i < Pad; i++)
     MCOS->EmitIntValue(0, 1);
 
-  // Now emit the table of pairs of PointerSize'ed values for the section(s)
-  // address and size, in our case just the one default .text section.
-  const MCExpr *Addr = MCSymbolRefExpr::Create(
-    context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
-  const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
-    *context.getGenDwarfSectionStartSym(), *SectionEndSym, 0);
-  MCOS->EmitValue(Addr, AddrSize);
-  MCOS->EmitAbsValue(Size, AddrSize);
+  // Now emit the table of pairs of PointerSize'ed values for the section
+  // addresses and sizes.
+  for (const auto &sec : Sections) {
+    MCSymbol *StartSymbol = sec.second.first;
+    MCSymbol *EndSymbol = sec.second.second;
+    assert(StartSymbol && "StartSymbol must not be NULL");
+    assert(EndSymbol && "EndSymbol must not be NULL");
+
+    const MCExpr *Addr = MCSymbolRefExpr::Create(
+      StartSymbol, MCSymbolRefExpr::VK_None, context);
+    const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
+      *StartSymbol, *EndSymbol, 0);
+    MCOS->EmitValue(Addr, AddrSize);
+    MCOS->EmitAbsValue(Size, AddrSize);
+  }
 
   // And finally the pair of terminating zeros.
   MCOS->EmitIntValue(0, AddrSize);
@@ -627,7 +633,8 @@ static void EmitGenDwarfAranges(MCStreamer *MCOS,
 // DIE and a list of label DIEs.
 static void EmitGenDwarfInfo(MCStreamer *MCOS,
                              const MCSymbol *AbbrevSectionSymbol,
-                             const MCSymbol *LineSectionSymbol) {
+                             const MCSymbol *LineSectionSymbol,
+                             const MCSymbol *RangesSectionSymbol) {
   MCContext &context = MCOS->getContext();
 
   MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
@@ -674,15 +681,37 @@ static void EmitGenDwarfInfo(MCStreamer *MCOS,
     MCOS->EmitIntValue(0, 4);
   }
 
-  // AT_low_pc, the first address of the default .text section.
-  const MCExpr *Start = MCSymbolRefExpr::Create(
-    context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
-  MCOS->EmitValue(Start, AddrSize);
+  if (RangesSectionSymbol) {
+    // There are multiple sections containing code, so we must use the
+    // .debug_ranges sections.
 
-  // AT_high_pc, the last address of the default .text section.
-  const MCExpr *End = MCSymbolRefExpr::Create(
-    context.getGenDwarfSectionEndSym(), MCSymbolRefExpr::VK_None, context);
-  MCOS->EmitValue(End, AddrSize);
+    // AT_ranges, the 4 byte offset from the start of the .debug_ranges section
+    // to the address range list for this compilation unit.
+    MCOS->EmitSymbolValue(RangesSectionSymbol, 4);
+  } else {
+    // If we only have one non-empty code section, we can use the simpler
+    // AT_low_pc and AT_high_pc attributes.
+
+    // Find the first (and only) non-empty text section
+    auto &Sections = context.getGenDwarfSectionSyms();
+    const auto TextSection = Sections.begin();
+    assert(TextSection != Sections.end() && "No text section found");
+
+    MCSymbol *StartSymbol = TextSection->second.first;
+    MCSymbol *EndSymbol = TextSection->second.second;
+    assert(StartSymbol && "StartSymbol must not be NULL");
+    assert(EndSymbol && "EndSymbol must not be NULL");
+
+    // AT_low_pc, the first address of the default .text section.
+    const MCExpr *Start = MCSymbolRefExpr::Create(
+        StartSymbol, MCSymbolRefExpr::VK_None, context);
+    MCOS->EmitValue(Start, AddrSize);
+
+    // AT_high_pc, the last address of the default .text section.
+    const MCExpr *End = MCSymbolRefExpr::Create(
+      EndSymbol, MCSymbolRefExpr::VK_None, context);
+    MCOS->EmitValue(End, AddrSize);
+  }
 
   // AT_name, the name of the source file.  Reconstruct from the first directory
   // and file table entries.
@@ -766,13 +795,51 @@ static void EmitGenDwarfInfo(MCStreamer *MCOS,
   MCOS->EmitLabel(InfoEnd);
 }
 
+// When generating dwarf for assembly source files this emits the data for
+// .debug_ranges section. We only emit one range list, which spans all of the
+// executable sections of this file.
+static void EmitGenDwarfRanges(MCStreamer *MCOS) {
+  MCContext &context = MCOS->getContext();
+  auto &Sections = context.getGenDwarfSectionSyms();
+
+  const MCAsmInfo *AsmInfo = context.getAsmInfo();
+  int AddrSize = AsmInfo->getPointerSize();
+
+  MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfRangesSection());
+
+  for (const auto sec : Sections) {
+
+    MCSymbol *StartSymbol = sec.second.first;
+    MCSymbol *EndSymbol = sec.second.second;
+    assert(StartSymbol && "StartSymbol must not be NULL");
+    assert(EndSymbol && "EndSymbol must not be NULL");
+
+    // Emit a base address selection entry for the start of this section
+    const MCExpr *SectionStartAddr = MCSymbolRefExpr::Create(
+      StartSymbol, MCSymbolRefExpr::VK_None, context);
+    MCOS->EmitFill(AddrSize, 0xFF);
+    MCOS->EmitValue(SectionStartAddr, AddrSize);
+
+    // Emit a range list entry spanning this section
+    const MCExpr *SectionSize = MakeStartMinusEndExpr(*MCOS,
+      *StartSymbol, *EndSymbol, 0);
+    MCOS->EmitIntValue(0, AddrSize);
+    MCOS->EmitAbsValue(SectionSize, AddrSize);
+  }
+
+  // Emit end of list entry
+  MCOS->EmitIntValue(0, AddrSize);
+  MCOS->EmitIntValue(0, AddrSize);
+}
+
 //
 // When generating dwarf for assembly source files this emits the Dwarf
 // sections.
 //
 void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
-  // Create the dwarf sections in this order (.debug_line already created).
   MCContext &context = MCOS->getContext();
+
+  // Create the dwarf sections in this order (.debug_line already created).
   const MCAsmInfo *AsmInfo = context.getAsmInfo();
   bool CreateDwarfSectionSymbols =
       AsmInfo->doesDwarfUseRelocationsAcrossSections();
@@ -781,6 +848,22 @@ void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
     LineSectionSymbol = MCOS->getDwarfLineTableSymbol(0);
   MCSymbol *AbbrevSectionSymbol = nullptr;
   MCSymbol *InfoSectionSymbol = nullptr;
+  MCSymbol *RangesSectionSymbol = NULL;
+
+  // Create end symbols for each section, and remove empty sections
+  MCOS->getContext().finalizeDwarfSections(*MCOS);
+
+  // If there are no sections to generate debug info for, we don't need
+  // to do anything
+  if (MCOS->getContext().getGenDwarfSectionSyms().empty())
+    return;
+
+  // We only need to use the .debug_ranges section if we have multiple
+  // code sections.
+  const bool UseRangesSection =
+      MCOS->getContext().getGenDwarfSectionSyms().size() > 1;
+  CreateDwarfSectionSymbols |= UseRangesSection;
+
   MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
   if (CreateDwarfSectionSymbols) {
     InfoSectionSymbol = context.CreateTempSymbol();
@@ -791,20 +874,30 @@ void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
     AbbrevSectionSymbol = context.CreateTempSymbol();
     MCOS->EmitLabel(AbbrevSectionSymbol);
   }
-  MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
+  if (UseRangesSection) {
+    MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfRangesSection());
+    if (CreateDwarfSectionSymbols) {
+      RangesSectionSymbol = context.CreateTempSymbol();
+      MCOS->EmitLabel(RangesSectionSymbol);
+    }
+  }
 
-  // If there are no line table entries then do not emit any section contents.
-  if (!context.hasMCLineSections())
-    return;
+  assert((RangesSectionSymbol != NULL) || !UseRangesSection);
+
+  MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
 
   // Output the data for .debug_aranges section.
   EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
 
+  if (UseRangesSection)
+    EmitGenDwarfRanges(MCOS);
+
   // Output the data for .debug_abbrev section.
   EmitGenDwarfAbbrev(MCOS);
 
   // Output the data for .debug_info section.
-  EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol);
+  EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol,
+                   RangesSectionSymbol);
 }
 
 //
@@ -815,12 +908,13 @@ void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
 //
 void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
                                      SourceMgr &SrcMgr, SMLoc &Loc) {
-  // We won't create dwarf labels for temporary symbols or symbols not in
-  // the default text.
+  // We won't create dwarf labels for temporary symbols.
   if (Symbol->isTemporary())
     return;
   MCContext &context = MCOS->getContext();
-  if (context.getGenDwarfSection() != MCOS->getCurrentSection().first)
+  // We won't create dwarf labels for symbols in sections that we are not
+  // generating debug info for.
+  if (!context.getGenDwarfSectionSyms().count(MCOS->getCurrentSection().first))
     return;
 
   // The dwarf label's name does not have the symbol name's leading
@@ -834,7 +928,7 @@ void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
 
   // Finding the line number is the expensive part which is why we just don't
   // pass it in as for some symbols we won't create a dwarf label.
-  int CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
+  unsigned CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
   unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
 
   // We create a temporary symbol for use for the AT_high_pc and AT_low_pc
@@ -1203,7 +1297,7 @@ void FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
   unsigned FDEEncoding = MOFI->getFDEEncoding();
   unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
   if (VerboseAsm) Streamer.AddComment("Range Start");
-  Streamer.EmitSymbolValue(Frame.Function, Size);
+  Streamer.EmitSymbolValue(Frame.Begin, Size);
 
   // Range Length
   const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
@@ -1246,12 +1340,7 @@ const MCSymbol &FrameEmitterImpl::EmitCIE(MCObjectStreamer &streamer,
   const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
   bool verboseAsm = streamer.isVerboseAsm();
 
-  MCSymbol *sectionStart;
-  if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
-    sectionStart = context.CreateTempSymbol();
-  else
-    sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
-
+  MCSymbol *sectionStart = context.CreateTempSymbol();
   streamer.EmitLabel(sectionStart);
   CIENum++;
 
@@ -1270,7 +1359,10 @@ const MCSymbol &FrameEmitterImpl::EmitCIE(MCObjectStreamer &streamer,
 
   // Version
   if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
-  streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
+  // For DWARF2, we use CIE version 1
+  // For DWARF3+, we use CIE version 3
+  uint8_t CIEVersion = context.getDwarfVersion() <= 2 ? 1 : 3;
+  streamer.EmitIntValue(CIEVersion, 1);
 
   // Augmentation String
   SmallString<8> Augmentation;
@@ -1298,7 +1390,14 @@ const MCSymbol &FrameEmitterImpl::EmitCIE(MCObjectStreamer &streamer,
 
   // Return Address Register
   if (verboseAsm) streamer.AddComment("CIE Return Address Column");
-  streamer.EmitULEB128IntValue(MRI->getDwarfRegNum(MRI->getRARegister(), true));
+  if (CIEVersion == 1) {
+    assert(MRI->getRARegister() <= 255 &&
+           "DWARF 2 encodes return_address_register in one byte");
+    streamer.EmitIntValue(MRI->getDwarfRegNum(MRI->getRARegister(), true), 1);
+  } else {
+    streamer.EmitULEB128IntValue(
+        MRI->getDwarfRegNum(MRI->getRARegister(), true));
+  }
 
   // Augmentation Data Length (optional)
 
@@ -1360,13 +1459,6 @@ MCSymbol *FrameEmitterImpl::EmitFDE(MCObjectStreamer &streamer,
   const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
   bool verboseAsm = streamer.isVerboseAsm();
 
-  if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
-    MCSymbol *EHSym =
-      context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
-    streamer.EmitEHSymAttributes(frame.Function, EHSym);
-    streamer.EmitLabel(EHSym);
-  }
-
   // Length
   const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
   if (verboseAsm) streamer.AddComment("FDE Length");
@@ -1435,13 +1527,12 @@ namespace {
       return CIEKey(nullptr, -1, 0, false, false);
     }
 
-    CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
-           unsigned LsdaEncoding_, bool IsSignalFrame_, bool IsSimple_) :
-      Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
-      LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_),
-      IsSimple(IsSimple_) {
-    }
-    const MCSymbol* Personality;
+    CIEKey(const MCSymbol *Personality_, unsigned PersonalityEncoding_,
+           unsigned LsdaEncoding_, bool IsSignalFrame_, bool IsSimple_)
+        : Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
+          LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_),
+          IsSimple(IsSimple_) {}
+    const MCSymbol *Personality;
     unsigned PersonalityEncoding;
     unsigned LsdaEncoding;
     bool IsSignalFrame;
@@ -1516,7 +1607,7 @@ void MCDwarfFrameEmitter::Emit(MCObjectStreamer &Streamer, MCAsmBackend *MAB,
   Emitter.setSectionStart(SectionStart);
 
   MCSymbol *FDEEnd = nullptr;
-  DenseMap<CIEKey, const MCSymbol*> CIEStarts;
+  DenseMap<CIEKey, const MCSymbol *> CIEStarts;
 
   const MCSymbol *DummyDebugKey = nullptr;
   NeedsEHFrameSection = !MOFI->getSupportsCompactUnwindWithoutEHFrame();
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index 767348c..7c70540 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -65,10 +65,6 @@ void MCELFStreamer::EmitLabel(MCSymbol *Symbol) {
     MCELF::SetType(SD, ELF::STT_TLS);
 }
 
-void MCELFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  EmitLabel(Symbol);
-}
-
 void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   // Let the target do whatever target specific stuff it needs to do.
   getAssembler().getBackend().handleAssemblerFlag(Flag);
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 37d05e9..9e8bc94 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -60,7 +60,6 @@ public:
 
   void ChangeSection(const MCSection *Sect, const MCExpr *Subsect) override;
   void EmitLabel(MCSymbol *Symbol) override;
-  void EmitDebugLabel(MCSymbol *Symbol) override;
   void EmitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol) override;
   void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
   void EmitLinkerOptions(ArrayRef<std::string> Options) override;
@@ -162,9 +161,6 @@ void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
   SD.setFlags(SD.getFlags() & ~SF_ReferenceTypeMask);
 }
 
-void MCMachOStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  EmitLabel(Symbol);
-}
 void MCMachOStreamer::EmitDataRegion(DataRegionData::KindTy Kind) {
   if (!getAssembler().getBackend().hasDataInCodeSupport())
     return;
diff --git a/lib/MC/MCNullStreamer.cpp b/lib/MC/MCNullStreamer.cpp
index 4f2740e..d543402 100644
--- a/lib/MC/MCNullStreamer.cpp
+++ b/lib/MC/MCNullStreamer.cpp
@@ -24,83 +24,17 @@ namespace {
     /// @name MCStreamer Interface
     /// @{
 
-    void ChangeSection(const MCSection *Section,
-                       const MCExpr *Subsection) override {
-    }
-
-    void EmitLabel(MCSymbol *Symbol) override {
-      assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
-      assert(getCurrentSection().first &&"Cannot emit before setting section!");
-      AssignSection(Symbol, getCurrentSection().first);
-    }
-    void EmitDebugLabel(MCSymbol *Symbol) override {
-      EmitLabel(Symbol);
-    }
-    void EmitAssemblerFlag(MCAssemblerFlag Flag) override {}
-    void EmitThumbFunc(MCSymbol *Func) override {}
-
-    void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) override {}
-    void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) override {}
     bool EmitSymbolAttribute(MCSymbol *Symbol,
                              MCSymbolAttr Attribute) override {
       return true;
     }
 
-    void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) override {}
-
-    void BeginCOFFSymbolDef(const MCSymbol *Symbol) override {}
-    void EmitCOFFSymbolStorageClass(int StorageClass) override {}
-    void EmitCOFFSymbolType(int Type) override {}
-    void EndCOFFSymbolDef() override {}
     void EmitCOFFSecRel32(MCSymbol const *Symbol) override {}
-
-    void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) override {}
     void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                           unsigned ByteAlignment) override {}
-    void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
-                               unsigned ByteAlignment) override {}
     void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = nullptr,
                       uint64_t Size = 0, unsigned ByteAlignment = 0) override {}
-    void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
-                        uint64_t Size, unsigned ByteAlignment) override {}
-    void EmitBytes(StringRef Data) override {}
-
-    void EmitValueImpl(const MCExpr *Value, unsigned Size,
-                       const SMLoc &Loc = SMLoc()) override {}
-    void EmitULEB128Value(const MCExpr *Value) override {}
-    void EmitSLEB128Value(const MCExpr *Value) override {}
     void EmitGPRel32Value(const MCExpr *Value) override {}
-    void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
-                              unsigned ValueSize = 1,
-                              unsigned MaxBytesToEmit = 0) override {}
-
-    void EmitCodeAlignment(unsigned ByteAlignment,
-                           unsigned MaxBytesToEmit = 0) override {}
-
-    bool EmitValueToOffset(const MCExpr *Offset,
-                           unsigned char Value = 0) override { return false; }
-
-    void EmitFileDirective(StringRef Filename) override {}
-    unsigned EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
-                                    StringRef Filename,
-                                    unsigned CUID = 0) override {
-      return 0;
-    }
-    void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
-                               unsigned Column, unsigned Flags,
-                               unsigned Isa, unsigned Discriminator,
-                               StringRef FileName) override {}
-    void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo&) override {}
-
-    void EmitBundleAlignMode(unsigned AlignPow2) override {}
-    void EmitBundleLock(bool AlignToEnd) override {}
-    void EmitBundleUnlock() override {}
-
-    void FinishImpl() override {}
-
-    void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) override {
-      RecordProcEnd(Frame);
-    }
   };
 
 }
diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index 9d413af..d490ef3 100644
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -18,9 +18,29 @@
 #include "llvm/MC/MCSectionMachO.h"
 using namespace llvm;
 
+static bool useCompactUnwind(const Triple &T) {
+  // Only on darwin.
+  if (!T.isOSDarwin())
+    return false;
+
+  // aarch64 always has it.
+  if (T.getArch() == Triple::arm64 || T.getArch() == Triple::aarch64)
+    return true;
+
+  // Use it on newer version of OS X.
+  if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
+    return true;
+
+  // And the iOS simulator.
+  if (T.isiOS() &&
+      (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
+    return true;
+
+  return false;
+}
+
 void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
   // MachO
-  IsFunctionEHFrameSymbolPrivate = false;
   SupportsWeakOmittedEHFrame = false;
 
   if (T.isOSDarwin() &&
@@ -151,13 +171,10 @@ void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
 
   COFFDebugSymbolsSection = nullptr;
 
-  if ((T.isMacOSX() && !T.isMacOSXVersionLT(10, 6)) ||
-      (T.isOSDarwin() &&
-       (T.getArch() == Triple::arm64 || T.getArch() == Triple::aarch64))) {
+  if (useCompactUnwind(T)) {
     CompactUnwindSection =
-      Ctx->getMachOSection("__LD", "__compact_unwind",
-                           MachO::S_ATTR_DEBUG,
-                           SectionKind::getReadOnly());
+        Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
+                             SectionKind::getReadOnly());
 
     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
       CompactUnwindDwarfEHFrameOnly = 0x04000000;
@@ -321,6 +338,13 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
       TTypeEncoding = dwarf::DW_EH_PE_absptr;
     }
     break;
+  case Triple::mips:
+  case Triple::mipsel:
+    // MIPS uses indirect pointer to refer personality functions, so that the
+    // eh_frame section can be read-only.  DW.ref.personality will be generated
+    // for relocation.
+    PersonalityEncoding = dwarf::DW_EH_PE_indirect;
+    break;
   case Triple::ppc64:
   case Triple::ppc64le:
     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
@@ -562,6 +586,8 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
 
 
 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
+  bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
+
   // The object file format cannot represent common symbols with explicit
   // alignments.
   CommDirectiveSupportsAlignment = false;
@@ -575,6 +601,8 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                         SectionKind::getBSS());
   TextSection =
     Ctx->getCOFFSection(".text",
+                        (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT
+                               : (COFF::SectionCharacteristics)0) |
                         COFF::IMAGE_SCN_CNT_CODE |
                         COFF::IMAGE_SCN_MEM_EXECUTE |
                         COFF::IMAGE_SCN_MEM_READ,
@@ -590,12 +618,18 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                         COFF::IMAGE_SCN_MEM_READ,
                         SectionKind::getReadOnly());
-  if (T.isKnownWindowsMSVCEnvironment()) {
+
+  if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
     StaticCtorSection =
       Ctx->getCOFFSection(".CRT$XCU",
                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                           COFF::IMAGE_SCN_MEM_READ,
                           SectionKind::getReadOnly());
+    StaticDtorSection =
+      Ctx->getCOFFSection(".CRT$XTX",
+                          COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
+                          COFF::IMAGE_SCN_MEM_READ,
+                          SectionKind::getReadOnly());
   } else {
     StaticCtorSection =
       Ctx->getCOFFSection(".ctors",
@@ -603,16 +637,6 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                           COFF::IMAGE_SCN_MEM_READ |
                           COFF::IMAGE_SCN_MEM_WRITE,
                           SectionKind::getDataRel());
-  }
-
-
-  if (T.isKnownWindowsMSVCEnvironment()) {
-    StaticDtorSection =
-      Ctx->getCOFFSection(".CRT$XTX",
-                          COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
-                          COFF::IMAGE_SCN_MEM_READ,
-                          SectionKind::getReadOnly());
-  } else {
     StaticDtorSection =
       Ctx->getCOFFSection(".dtors",
                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
@@ -625,11 +649,16 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
   // 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 =
-    Ctx->getCOFFSection(".gcc_except_table",
-                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
-                        COFF::IMAGE_SCN_MEM_READ,
-                        SectionKind::getReadOnly());
+  assert(T.isOSWindows() && "Windows is the only supported COFF target");
+  if (T.getArch() == Triple::x86_64) {
+    // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
+    LSDASection = 0;
+  } else {
+    LSDASection = Ctx->getCOFFSection(".gcc_except_table",
+                                      COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
+                                          COFF::IMAGE_SCN_MEM_READ,
+                                      SectionKind::getReadOnly());
+  }
 
   // Debug info.
   COFFDebugSymbolsSection =
@@ -705,36 +734,46 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                         COFF::IMAGE_SCN_MEM_READ,
                         SectionKind::getMetadata());
   DwarfInfoDWOSection =
-      Ctx->getCOFFSection(".debug_info.dwo", COFF::IMAGE_SCN_MEM_DISCARDABLE |
-                                                COFF::IMAGE_SCN_MEM_READ,
+      Ctx->getCOFFSection(".debug_info.dwo",
+                          COFF::IMAGE_SCN_MEM_DISCARDABLE |
+                          COFF::IMAGE_SCN_MEM_READ,
                           SectionKind::getMetadata());
   DwarfAbbrevDWOSection =
-      Ctx->getCOFFSection(".debug_abbrev.dwo", COFF::IMAGE_SCN_MEM_DISCARDABLE |
-                                                  COFF::IMAGE_SCN_MEM_READ,
+      Ctx->getCOFFSection(".debug_abbrev.dwo",
+                          COFF::IMAGE_SCN_MEM_DISCARDABLE |
+                          COFF::IMAGE_SCN_MEM_READ,
                           SectionKind::getMetadata());
   DwarfStrDWOSection =
-      Ctx->getCOFFSection(".debug_str.dwo", COFF::IMAGE_SCN_MEM_DISCARDABLE |
-                                               COFF::IMAGE_SCN_MEM_READ,
+      Ctx->getCOFFSection(".debug_str.dwo",
+                          COFF::IMAGE_SCN_MEM_DISCARDABLE |
+                          COFF::IMAGE_SCN_MEM_READ,
                           SectionKind::getMetadata());
   DwarfLineDWOSection =
-      Ctx->getCOFFSection(".debug_line.dwo", COFF::IMAGE_SCN_MEM_DISCARDABLE |
-                                                COFF::IMAGE_SCN_MEM_READ,
+      Ctx->getCOFFSection(".debug_line.dwo",
+                          COFF::IMAGE_SCN_MEM_DISCARDABLE |
+                          COFF::IMAGE_SCN_MEM_READ,
                           SectionKind::getMetadata());
   DwarfLocDWOSection =
-      Ctx->getCOFFSection(".debug_loc.dwo", COFF::IMAGE_SCN_MEM_DISCARDABLE |
-                                               COFF::IMAGE_SCN_MEM_READ,
+      Ctx->getCOFFSection(".debug_loc.dwo",
+                          COFF::IMAGE_SCN_MEM_DISCARDABLE |
+                          COFF::IMAGE_SCN_MEM_READ,
                           SectionKind::getMetadata());
   DwarfStrOffDWOSection =
-      Ctx->getCOFFSection(".debug_str_offsets.dwo", COFF::IMAGE_SCN_MEM_DISCARDABLE |
-                                                  COFF::IMAGE_SCN_MEM_READ,
+      Ctx->getCOFFSection(".debug_str_offsets.dwo",
+                          COFF::IMAGE_SCN_MEM_DISCARDABLE |
+                          COFF::IMAGE_SCN_MEM_READ,
                           SectionKind::getMetadata());
-  DwarfAddrSection = Ctx->getCOFFSection(
-      ".debug_addr", COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_MEM_READ,
-      SectionKind::getMetadata());
+
+  DwarfAddrSection =
+    Ctx->getCOFFSection(".debug_addr",
+                        COFF::IMAGE_SCN_MEM_DISCARDABLE |
+                        COFF::IMAGE_SCN_MEM_READ,
+                        SectionKind::getMetadata());
 
   DrectveSection =
     Ctx->getCOFFSection(".drectve",
-                        COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
+                        COFF::IMAGE_SCN_LNK_INFO |
+                        COFF::IMAGE_SCN_LNK_REMOVE,
                         SectionKind::getMetadata());
 
   PDataSection =
@@ -748,6 +787,7 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                         COFF::IMAGE_SCN_MEM_READ,
                         SectionKind::getDataRel());
+
   TLSDataSection =
     Ctx->getCOFFSection(".tls$",
                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
@@ -756,7 +796,7 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                         SectionKind::getDataRel());
 }
 
-void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
+void MCObjectFileInfo::InitMCObjectFileInfo(StringRef T, Reloc::Model relocm,
                                             CodeModel::Model cm,
                                             MCContext &ctx) {
   RelocM = relocm;
@@ -766,7 +806,6 @@ void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
   // Common.
   CommDirectiveSupportsAlignment = true;
   SupportsWeakOmittedEHFrame = true;
-  IsFunctionEHFrameSymbolPrivate = true;
   SupportsCompactUnwindWithoutEHFrame = false;
 
   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
@@ -781,8 +820,9 @@ void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 
-  Triple T(TT);
-  Triple::ArchType Arch = T.getArch();
+  TT = Triple(T);
+
+  Triple::ArchType Arch = TT.getArch();
   // FIXME: Checking for Arch here to filter out bogus triples such as
   // cellspu-apple-darwin. Perhaps we should fix in Triple?
   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
@@ -790,17 +830,17 @@ void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
        Arch == Triple::arm64 || Arch == Triple::aarch64 ||
        Arch == Triple::ppc || Arch == Triple::ppc64 ||
        Arch == Triple::UnknownArch) &&
-      (T.isOSDarwin() || T.isOSBinFormatMachO())) {
+      (TT.isOSDarwin() || TT.isOSBinFormatMachO())) {
     Env = IsMachO;
-    InitMachOMCObjectFileInfo(T);
+    InitMachOMCObjectFileInfo(TT);
   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
               Arch == Triple::arm || Arch == Triple::thumb) &&
-             (T.isOSWindows() && T.getObjectFormat() == Triple::COFF)) {
+             (TT.isOSWindows() && TT.getObjectFormat() == Triple::COFF)) {
     Env = IsCOFF;
-    InitCOFFMCObjectFileInfo(T);
+    InitCOFFMCObjectFileInfo(TT);
   } else {
     Env = IsELF;
-    InitELFMCObjectFileInfo(T);
+    InitELFMCObjectFileInfo(TT);
   }
 }
 
diff --git a/lib/MC/MCObjectStreamer.cpp b/lib/MC/MCObjectStreamer.cpp
index a1aa602..a721b59 100644
--- a/lib/MC/MCObjectStreamer.cpp
+++ b/lib/MC/MCObjectStreamer.cpp
@@ -83,32 +83,8 @@ MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() const {
   return F;
 }
 
-const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) {
-  switch (Value->getKind()) {
-  case MCExpr::Target:
-    cast<MCTargetExpr>(Value)->AddValueSymbols(Assembler);
-    break;
-
-  case MCExpr::Constant:
-    break;
-
-  case MCExpr::Binary: {
-    const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
-    AddValueSymbols(BE->getLHS());
-    AddValueSymbols(BE->getRHS());
-    break;
-  }
-
-  case MCExpr::SymbolRef:
-    Assembler->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
-    break;
-
-  case MCExpr::Unary:
-    AddValueSymbols(cast<MCUnaryExpr>(Value)->getSubExpr());
-    break;
-  }
-
-  return Value;
+void MCObjectStreamer::visitUsedSymbol(const MCSymbol &Sym) {
+  Assembler->getOrCreateSymbolData(Sym);
 }
 
 void MCObjectStreamer::EmitCFISections(bool EH, bool Debug) {
@@ -119,13 +95,14 @@ void MCObjectStreamer::EmitCFISections(bool EH, bool Debug) {
 
 void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
                                      const SMLoc &Loc) {
+  MCStreamer::EmitValueImpl(Value, Size, Loc);
   MCDataFragment *DF = getOrCreateDataFragment();
 
   MCLineEntry::Make(this, getCurrentSection().first);
 
   // Avoid fixups when possible.
   int64_t AbsValue;
-  if (AddValueSymbols(Value)->EvaluateAsAbsolute(AbsValue, getAssembler())) {
+  if (Value->EvaluateAsAbsolute(AbsValue, getAssembler())) {
     EmitIntValue(AbsValue, Size);
     return;
   }
@@ -136,11 +113,14 @@ void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
 }
 
 void MCObjectStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
-  RecordProcStart(Frame);
+  // We need to create a local symbol to avoid relocations.
+  Frame.Begin = getContext().CreateTempSymbol();
+  EmitLabel(Frame.Begin);
 }
 
 void MCObjectStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
-  RecordProcEnd(Frame);
+  Frame.End = getContext().CreateTempSymbol();
+  EmitLabel(Frame.End);
 }
 
 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
@@ -158,10 +138,6 @@ void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
   SD.setOffset(F->getContents().size());
 }
 
-void MCObjectStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  EmitLabel(Symbol);
-}
-
 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
   int64_t IntValue;
   if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
@@ -205,15 +181,12 @@ void MCObjectStreamer::ChangeSection(const MCSection *Section,
 
 void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
   getAssembler().getOrCreateSymbolData(*Symbol);
-  AddValueSymbols(Value);
   MCStreamer::EmitAssignment(Symbol, Value);
 }
 
-void MCObjectStreamer::EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI) {
-  // Scan for values.
-  for (unsigned i = Inst.getNumOperands(); i--; )
-    if (Inst.getOperand(i).isExpr())
-      AddValueSymbols(Inst.getOperand(i).getExpr());
+void MCObjectStreamer::EmitInstruction(const MCInst &Inst,
+                                       const MCSubtargetInfo &STI) {
+  MCStreamer::EmitInstruction(Inst, STI);
 
   MCSectionData *SD = getCurrentSectionData();
   SD->setHasInstructions(true);
diff --git a/lib/MC/MCParser/AsmLexer.cpp b/lib/MC/MCParser/AsmLexer.cpp
index bca516e..145ad4a 100644
--- a/lib/MC/MCParser/AsmLexer.cpp
+++ b/lib/MC/MCParser/AsmLexer.cpp
@@ -22,7 +22,6 @@
 using namespace llvm;
 
 AsmLexer::AsmLexer(const MCAsmInfo &_MAI) : MAI(_MAI)  {
-  CurBuf = nullptr;
   CurPtr = nullptr;
   isAtStartOfLine = true;
   AllowAtInIdentifier = !StringRef(MAI.getCommentString()).startswith("@");
@@ -31,13 +30,13 @@ AsmLexer::AsmLexer(const MCAsmInfo &_MAI) : MAI(_MAI)  {
 AsmLexer::~AsmLexer() {
 }
 
-void AsmLexer::setBuffer(const MemoryBuffer *buf, const char *ptr) {
-  CurBuf = buf;
+void AsmLexer::setBuffer(StringRef Buf, const char *ptr) {
+  CurBuf = Buf;
 
   if (ptr)
     CurPtr = ptr;
   else
-    CurPtr = CurBuf->getBufferStart();
+    CurPtr = CurBuf.begin();
 
   TokStart = nullptr;
 }
@@ -58,7 +57,7 @@ int AsmLexer::getNextChar() {
   case 0:
     // A nul character in the stream is either the end of the current buffer or
     // a random nul in the file.  Disambiguate that here.
-    if (CurPtr-1 != CurBuf->getBufferEnd())
+    if (CurPtr - 1 != CurBuf.end())
       return 0;  // Just whitespace.
 
     // Otherwise, return end of file.
@@ -201,8 +200,8 @@ AsmToken AsmLexer::LexLineComment() {
     CurChar = getNextChar();
 
   if (CurChar == EOF)
-    return AsmToken(AsmToken::Eof, StringRef(CurPtr, 0));
-  return AsmToken(AsmToken::EndOfStatement, StringRef(CurPtr, 0));
+    return AsmToken(AsmToken::Eof, StringRef(TokStart, 0));
+  return AsmToken(AsmToken::EndOfStatement, StringRef(TokStart, 0));
 }
 
 static void SkipIgnoredIntegerSuffix(const char *&CurPtr) {
@@ -420,9 +419,8 @@ StringRef AsmLexer::LexUntilEndOfStatement() {
 
   while (!isAtStartOfComment(*CurPtr) &&    // Start of line comment.
          !isAtStatementSeparator(CurPtr) && // End of statement marker.
-         *CurPtr != '\n' &&
-         *CurPtr != '\r' &&
-         (*CurPtr != 0 || CurPtr != CurBuf->getBufferEnd())) {
+         *CurPtr != '\n' && *CurPtr != '\r' &&
+         (*CurPtr != 0 || CurPtr != CurBuf.end())) {
     ++CurPtr;
   }
   return StringRef(TokStart, CurPtr-TokStart);
@@ -431,9 +429,8 @@ StringRef AsmLexer::LexUntilEndOfStatement() {
 StringRef AsmLexer::LexUntilEndOfLine() {
   TokStart = CurPtr;
 
-  while (*CurPtr != '\n' &&
-         *CurPtr != '\r' &&
-         (*CurPtr != 0 || CurPtr != CurBuf->getBufferEnd())) {
+  while (*CurPtr != '\n' && *CurPtr != '\r' &&
+         (*CurPtr != 0 || CurPtr != CurBuf.end())) {
     ++CurPtr;
   }
   return StringRef(TokStart, CurPtr-TokStart);
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 168597f..62ab4a5 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -102,7 +102,7 @@ public:
 
 struct ParseStatementInfo {
   /// \brief The parsed operands from the last parsed statement.
-  SmallVector<MCParsedAsmOperand*, 8> ParsedOperands;
+  SmallVector<std::unique_ptr<MCParsedAsmOperand>, 8> ParsedOperands;
 
   /// \brief The opcode from the last parsed instruction.
   unsigned Opcode;
@@ -115,13 +115,6 @@ struct ParseStatementInfo {
   ParseStatementInfo() : Opcode(~0U), ParseError(false), AsmRewrites(nullptr) {}
   ParseStatementInfo(SmallVectorImpl<AsmRewrite> *rewrites)
     : Opcode(~0), ParseError(false), AsmRewrites(rewrites) {}
-
-  ~ParseStatementInfo() {
-    // Free any parsed operands.
-    for (unsigned i = 0, e = ParsedOperands.size(); i != e; ++i)
-      delete ParsedOperands[i];
-    ParsedOperands.clear();
-  }
 };
 
 /// \brief The concrete assembly parser instance.
@@ -140,7 +133,7 @@ private:
 
   /// This is the current buffer index we're lexing from as managed by the
   /// SourceMgr object.
-  int CurBuffer;
+  unsigned CurBuffer;
 
   AsmCond TheCondState;
   std::vector<AsmCond> TheCondStack;
@@ -169,13 +162,13 @@ private:
   StringRef CppHashFilename;
   int64_t CppHashLineNumber;
   SMLoc CppHashLoc;
-  int CppHashBuf;
+  unsigned CppHashBuf;
   /// When generating dwarf for assembly source files we need to calculate the
   /// logical line number based on the last parsed cpp hash file line comment
   /// and current line. Since this is slow and messes up the SourceMgr's
   /// cache we save the last info we queried with SrcMgr.FindLineNumber().
   SMLoc LastQueryIDLoc;
-  int LastQueryBuffer;
+  unsigned LastQueryBuffer;
   unsigned LastQueryLine;
 
   /// AssemblerDialect. ~OU means unset value and use value provided by MAI.
@@ -317,9 +310,9 @@ private:
   /// current token is not set; clients should ensure Lex() is called
   /// subsequently.
   ///
-  /// \param InBuffer If not -1, should be the known buffer id that contains the
+  /// \param InBuffer If not 0, should be the known buffer id that contains the
   /// location.
-  void jumpToLoc(SMLoc Loc, int InBuffer=-1);
+  void jumpToLoc(SMLoc Loc, unsigned InBuffer = 0);
 
   /// \brief Parse up to the end of statement and a return the contents from the
   /// current token until the end of the statement; the current token on exit
@@ -352,8 +345,9 @@ private:
     DK_REFERENCE, DK_WEAK_DEFINITION, DK_WEAK_REFERENCE,
     DK_WEAK_DEF_CAN_BE_HIDDEN, DK_COMM, DK_COMMON, DK_LCOMM, DK_ABORT,
     DK_INCLUDE, DK_INCBIN, DK_CODE16, DK_CODE16GCC, DK_REPT, DK_IRP, DK_IRPC,
-    DK_IF, DK_IFNE, DK_IFB, DK_IFNB, DK_IFC, DK_IFEQS, DK_IFNC, DK_IFDEF,
-    DK_IFNDEF, DK_IFNOTDEF, DK_ELSEIF, DK_ELSE, DK_ENDIF,
+    DK_IF, DK_IFEQ, DK_IFGE, DK_IFGT, DK_IFLE, DK_IFLT, DK_IFNE, DK_IFB,
+    DK_IFNB, DK_IFC, DK_IFEQS, DK_IFNC, DK_IFDEF, DK_IFNDEF, DK_IFNOTDEF,
+    DK_ELSEIF, DK_ELSE, DK_ENDIF,
     DK_SPACE, DK_SKIP, DK_FILE, DK_LINE, DK_LOC, DK_STABS,
     DK_CFI_SECTIONS, DK_CFI_STARTPROC, DK_CFI_ENDPROC, DK_CFI_DEF_CFA,
     DK_CFI_DEF_CFA_OFFSET, DK_CFI_ADJUST_CFA_OFFSET, DK_CFI_DEF_CFA_REGISTER,
@@ -440,8 +434,8 @@ private:
   bool parseDirectiveInclude(); // ".include"
   bool parseDirectiveIncbin(); // ".incbin"
 
-  // ".if" or ".ifne"
-  bool parseDirectiveIf(SMLoc DirectiveLoc);
+  // ".if", ".ifeq", ".ifge", ".ifgt" , ".ifle", ".iflt" or ".ifne"
+  bool parseDirectiveIf(SMLoc DirectiveLoc, DirectiveKind DirKind);
   // ".ifb" or ".ifnb", depending on ExpectBlank.
   bool parseDirectiveIfb(SMLoc DirectiveLoc, bool ExpectBlank);
   // ".ifc" or ".ifnc", depending on ExpectEqual.
@@ -497,15 +491,15 @@ enum { DEFAULT_ADDRSPACE = 0 };
 AsmParser::AsmParser(SourceMgr &_SM, MCContext &_Ctx, MCStreamer &_Out,
                      const MCAsmInfo &_MAI)
     : Lexer(_MAI), Ctx(_Ctx), Out(_Out), MAI(_MAI), SrcMgr(_SM),
-      PlatformParser(nullptr), CurBuffer(0), MacrosEnabledFlag(true),
-      HadError(false), CppHashLineNumber(0), AssemblerDialect(~0U),
-      IsDarwin(false), ParsingInlineAsm(false) {
+      PlatformParser(nullptr), CurBuffer(_SM.getMainFileID()),
+      MacrosEnabledFlag(true), HadError(false), CppHashLineNumber(0),
+      AssemblerDialect(~0U), IsDarwin(false), ParsingInlineAsm(false) {
   // Save the old handler.
   SavedDiagHandler = SrcMgr.getDiagHandler();
   SavedDiagContext = SrcMgr.getDiagContext();
   // Set our own handler which calls the saved handler.
   SrcMgr.setDiagHandler(DiagHandler, this);
-  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer));
+  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer());
 
   // Initialize the platform / file format parser.
   switch (_Ctx.getObjectFileInfo()->getObjectFileType()) {
@@ -572,14 +566,13 @@ bool AsmParser::Error(SMLoc L, const Twine &Msg, ArrayRef<SMRange> Ranges) {
 
 bool AsmParser::enterIncludeFile(const std::string &Filename) {
   std::string IncludedFile;
-  int NewBuf = SrcMgr.AddIncludeFile(Filename, Lexer.getLoc(), IncludedFile);
-  if (NewBuf == -1)
+  unsigned NewBuf =
+      SrcMgr.AddIncludeFile(Filename, Lexer.getLoc(), IncludedFile);
+  if (!NewBuf)
     return true;
 
   CurBuffer = NewBuf;
-
-  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer));
-
+  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer());
   return false;
 }
 
@@ -588,8 +581,9 @@ bool AsmParser::enterIncludeFile(const std::string &Filename) {
 /// returns true on failure.
 bool AsmParser::processIncbinFile(const std::string &Filename) {
   std::string IncludedFile;
-  int NewBuf = SrcMgr.AddIncludeFile(Filename, Lexer.getLoc(), IncludedFile);
-  if (NewBuf == -1)
+  unsigned NewBuf =
+      SrcMgr.AddIncludeFile(Filename, Lexer.getLoc(), IncludedFile);
+  if (!NewBuf)
     return true;
 
   // Pick up the bytes from the file and emit them.
@@ -597,13 +591,10 @@ bool AsmParser::processIncbinFile(const std::string &Filename) {
   return false;
 }
 
-void AsmParser::jumpToLoc(SMLoc Loc, int InBuffer) {
-  if (InBuffer != -1) {
-    CurBuffer = InBuffer;
-  } else {
-    CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
-  }
-  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer), Loc.getPointer());
+void AsmParser::jumpToLoc(SMLoc Loc, unsigned InBuffer) {
+  CurBuffer = InBuffer ? InBuffer : SrcMgr.FindBufferContainingLoc(Loc);
+  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer(),
+                  Loc.getPointer());
 }
 
 const AsmToken &AsmParser::Lex() {
@@ -639,10 +630,12 @@ bool AsmParser::Run(bool NoInitialTextSection, bool NoFinalize) {
   // If we are generating dwarf for assembly source files save the initial text
   // section and generate a .file directive.
   if (getContext().getGenDwarfForAssembly()) {
-    getContext().setGenDwarfSection(getStreamer().getCurrentSection().first);
     MCSymbol *SectionStartSym = getContext().CreateTempSymbol();
     getStreamer().EmitLabel(SectionStartSym);
-    getContext().setGenDwarfSectionStartSym(SectionStartSym);
+    auto InsertResult = getContext().addGenDwarfSection(
+        getStreamer().getCurrentSection().first);
+    assert(InsertResult.second && ".text section should not have debug info yet");
+    InsertResult.first->second.first = SectionStartSym;
     getContext().setGenDwarfFileNumber(getStreamer().EmitDwarfFileDirective(
         0, StringRef(), getContext().getMainFileName()));
   }
@@ -818,7 +811,19 @@ bool AsmParser::parsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
     // Parse symbol variant
     std::pair<StringRef, StringRef> Split;
     if (!MAI.useParensForSymbolVariant()) {
-      Split = Identifier.split('@');
+      if (FirstTokenKind == AsmToken::String) {
+        if (Lexer.is(AsmToken::At)) {
+          Lexer.Lex(); // eat @
+          SMLoc AtLoc = getLexer().getLoc();
+          StringRef VName;
+          if (parseIdentifier(VName))
+            return Error(AtLoc, "expected symbol variant after '@'");
+
+          Split = std::make_pair(Identifier, VName);
+        }
+      } else {
+        Split = Identifier.split('@');
+      }
     } else if (Lexer.is(AsmToken::LParen)) {
       Lexer.Lex(); // eat (
       StringRef VName;
@@ -1236,8 +1241,13 @@ bool AsmParser::parseStatement(ParseStatementInfo &Info) {
   default:
     break;
   case DK_IF:
+  case DK_IFEQ:
+  case DK_IFGE:
+  case DK_IFGT:
+  case DK_IFLE:
+  case DK_IFLT:
   case DK_IFNE:
-    return parseDirectiveIf(IDLoc);
+    return parseDirectiveIf(IDLoc, DirKind);
   case DK_IFB:
     return parseDirectiveIfb(IDLoc, true);
   case DK_IFNB:
@@ -1581,12 +1591,11 @@ bool AsmParser::parseStatement(ParseStatementInfo &Info) {
     printMessage(IDLoc, SourceMgr::DK_Note, OS.str());
   }
 
-  // If we are generating dwarf for assembly source files and the current
-  // section is the initial text section then generate a .loc directive for
-  // the instruction.
+  // If we are generating dwarf for the current section then generate a .loc
+  // directive for the instruction.
   if (!HadError && getContext().getGenDwarfForAssembly() &&
-      getContext().getGenDwarfSection() ==
-          getStreamer().getCurrentSection().first) {
+      getContext().getGenDwarfSectionSyms().count(
+        getStreamer().getCurrentSection().first)) {
 
     unsigned Line = SrcMgr.FindLineNumber(IDLoc, CurBuffer);
 
@@ -1685,13 +1694,15 @@ void AsmParser::DiagHandler(const SMDiagnostic &Diag, void *Context) {
 
   const SourceMgr &DiagSrcMgr = *Diag.getSourceMgr();
   const SMLoc &DiagLoc = Diag.getLoc();
-  int DiagBuf = DiagSrcMgr.FindBufferContainingLoc(DiagLoc);
-  int CppHashBuf = Parser->SrcMgr.FindBufferContainingLoc(Parser->CppHashLoc);
+  unsigned DiagBuf = DiagSrcMgr.FindBufferContainingLoc(DiagLoc);
+  unsigned CppHashBuf =
+      Parser->SrcMgr.FindBufferContainingLoc(Parser->CppHashLoc);
 
   // Like SourceMgr::printMessage() we need to print the include stack if any
   // before printing the message.
-  int DiagCurBuffer = DiagSrcMgr.FindBufferContainingLoc(DiagLoc);
-  if (!Parser->SavedDiagHandler && DiagCurBuffer > 0) {
+  unsigned DiagCurBuffer = DiagSrcMgr.FindBufferContainingLoc(DiagLoc);
+  if (!Parser->SavedDiagHandler && DiagCurBuffer &&
+      DiagCurBuffer != DiagSrcMgr.getMainFileID()) {
     SMLoc ParentIncludeLoc = DiagSrcMgr.getParentIncludeLoc(DiagCurBuffer);
     DiagSrcMgr.PrintIncludeStack(ParentIncludeLoc, OS);
   }
@@ -2018,7 +2029,7 @@ bool AsmParser::parseMacroArguments(const MCAsmMacro *M,
           break;
 
       if (FAI >= NParameters) {
-	assert(M && "expected macro to be defined");
+    assert(M && "expected macro to be defined");
         Error(IDLoc,
               "parameter named '" + FA.Name + "' does not exist for macro '" +
               M->Name + "'");
@@ -2117,7 +2128,7 @@ bool AsmParser::handleMacroEntry(const MCAsmMacro *M, SMLoc NameLoc) {
 
   // Jump to the macro instantiation and prime the lexer.
   CurBuffer = SrcMgr.AddNewSourceBuffer(MI->Instantiation, SMLoc());
-  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer));
+  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer());
   Lex();
 
   return false;
@@ -3799,9 +3810,8 @@ bool AsmParser::parseDirectiveIncbin() {
 }
 
 /// parseDirectiveIf
-/// ::= .if expression
-/// ::= .ifne expression
-bool AsmParser::parseDirectiveIf(SMLoc DirectiveLoc) {
+/// ::= .if{,eq,ge,gt,le,lt,ne} expression
+bool AsmParser::parseDirectiveIf(SMLoc DirectiveLoc, DirectiveKind DirKind) {
   TheCondStack.push_back(TheCondState);
   TheCondState.TheCond = AsmCond::IfCond;
   if (TheCondState.Ignore) {
@@ -3816,6 +3826,29 @@ bool AsmParser::parseDirectiveIf(SMLoc DirectiveLoc) {
 
     Lex();
 
+    switch (DirKind) {
+    default:
+      llvm_unreachable("unsupported directive");
+    case DK_IF:
+    case DK_IFNE:
+      break;
+    case DK_IFEQ:
+      ExprValue = ExprValue == 0;
+      break;
+    case DK_IFGE:
+      ExprValue = ExprValue >= 0;
+      break;
+    case DK_IFGT:
+      ExprValue = ExprValue > 0;
+      break;
+    case DK_IFLE:
+      ExprValue = ExprValue <= 0;
+      break;
+    case DK_IFLT:
+      ExprValue = ExprValue < 0;
+      break;
+    }
+
     TheCondState.CondMet = ExprValue;
     TheCondState.Ignore = !TheCondState.CondMet;
   }
@@ -4118,6 +4151,11 @@ void AsmParser::initializeDirectiveKindMap() {
   DirectiveKindMap[".bundle_lock"] = DK_BUNDLE_LOCK;
   DirectiveKindMap[".bundle_unlock"] = DK_BUNDLE_UNLOCK;
   DirectiveKindMap[".if"] = DK_IF;
+  DirectiveKindMap[".ifeq"] = DK_IFEQ;
+  DirectiveKindMap[".ifge"] = DK_IFGE;
+  DirectiveKindMap[".ifgt"] = DK_IFGT;
+  DirectiveKindMap[".ifle"] = DK_IFLE;
+  DirectiveKindMap[".iflt"] = DK_IFLT;
   DirectiveKindMap[".ifne"] = DK_IFNE;
   DirectiveKindMap[".ifb"] = DK_IFB;
   DirectiveKindMap[".ifnb"] = DK_IFNB;
@@ -4227,7 +4265,7 @@ void AsmParser::instantiateMacroLikeBody(MCAsmMacro *M, SMLoc DirectiveLoc,
 
   // Jump to the macro instantiation and prime the lexer.
   CurBuffer = SrcMgr.AddNewSourceBuffer(MI->Instantiation, SMLoc());
-  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer));
+  Lexer.setBuffer(SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer());
   Lex();
 }
 
@@ -4465,27 +4503,27 @@ bool AsmParser::parseMSInlineAsm(
 
     // Build the list of clobbers, outputs and inputs.
     for (unsigned i = 1, e = Info.ParsedOperands.size(); i != e; ++i) {
-      MCParsedAsmOperand *Operand = Info.ParsedOperands[i];
+      MCParsedAsmOperand &Operand = *Info.ParsedOperands[i];
 
       // Immediate.
-      if (Operand->isImm())
+      if (Operand.isImm())
         continue;
 
       // Register operand.
-      if (Operand->isReg() && !Operand->needAddressOf()) {
+      if (Operand.isReg() && !Operand.needAddressOf()) {
         unsigned NumDefs = Desc.getNumDefs();
         // Clobber.
-        if (NumDefs && Operand->getMCOperandNum() < NumDefs)
-          ClobberRegs.push_back(Operand->getReg());
+        if (NumDefs && Operand.getMCOperandNum() < NumDefs)
+          ClobberRegs.push_back(Operand.getReg());
         continue;
       }
 
       // Expr/Input or Output.
-      StringRef SymName = Operand->getSymName();
+      StringRef SymName = Operand.getSymName();
       if (SymName.empty())
         continue;
 
-      void *OpDecl = Operand->getOpDecl();
+      void *OpDecl = Operand.getOpDecl();
       if (!OpDecl)
         continue;
 
@@ -4494,21 +4532,21 @@ bool AsmParser::parseMSInlineAsm(
       if (isOutput) {
         ++InputIdx;
         OutputDecls.push_back(OpDecl);
-        OutputDeclsAddressOf.push_back(Operand->needAddressOf());
-        OutputConstraints.push_back('=' + Operand->getConstraint().str());
+        OutputDeclsAddressOf.push_back(Operand.needAddressOf());
+        OutputConstraints.push_back('=' + Operand.getConstraint().str());
         AsmStrRewrites.push_back(AsmRewrite(AOK_Output, Start, SymName.size()));
       } else {
         InputDecls.push_back(OpDecl);
-        InputDeclsAddressOf.push_back(Operand->needAddressOf());
-        InputConstraints.push_back(Operand->getConstraint().str());
+        InputDeclsAddressOf.push_back(Operand.needAddressOf());
+        InputConstraints.push_back(Operand.getConstraint().str());
         AsmStrRewrites.push_back(AsmRewrite(AOK_Input, Start, SymName.size()));
       }
     }
 
     // Consider implicit defs to be clobbers.  Think of cpuid and push.
-    const uint16_t *ImpDefs = Desc.getImplicitDefs();
-    for (unsigned I = 0, E = Desc.getNumImplicitDefs(); I != E; ++I)
-      ClobberRegs.push_back(ImpDefs[I]);
+    ArrayRef<uint16_t> ImpDefs(Desc.getImplicitDefs(),
+                               Desc.getNumImplicitDefs());
+    ClobberRegs.insert(ClobberRegs.end(), ImpDefs.begin(), ImpDefs.end());
   }
 
   // Set the number of Outputs and Inputs.
@@ -4543,27 +4581,26 @@ bool AsmParser::parseMSInlineAsm(
   // Build the IR assembly string.
   std::string AsmStringIR;
   raw_string_ostream OS(AsmStringIR);
-  const char *AsmStart = SrcMgr.getMemoryBuffer(0)->getBufferStart();
-  const char *AsmEnd = SrcMgr.getMemoryBuffer(0)->getBufferEnd();
+  StringRef ASMString =
+      SrcMgr.getMemoryBuffer(SrcMgr.getMainFileID())->getBuffer();
+  const char *AsmStart = ASMString.begin();
+  const char *AsmEnd = ASMString.end();
   array_pod_sort(AsmStrRewrites.begin(), AsmStrRewrites.end(), rewritesSort);
-  for (SmallVectorImpl<AsmRewrite>::iterator I = AsmStrRewrites.begin(),
-                                             E = AsmStrRewrites.end();
-       I != E; ++I) {
-    AsmRewriteKind Kind = (*I).Kind;
+  for (const AsmRewrite &AR : AsmStrRewrites) {
+    AsmRewriteKind Kind = AR.Kind;
     if (Kind == AOK_Delete)
       continue;
 
-    const char *Loc = (*I).Loc.getPointer();
+    const char *Loc = AR.Loc.getPointer();
     assert(Loc >= AsmStart && "Expected Loc to be at or after Start!");
 
     // Emit everything up to the immediate/expression.
-    unsigned Len = Loc - AsmStart;
-    if (Len)
+    if (unsigned Len = Loc - AsmStart)
       OS << StringRef(AsmStart, Len);
 
     // Skip the original expression.
     if (Kind == AOK_Skip) {
-      AsmStart = Loc + (*I).Len;
+      AsmStart = Loc + AR.Len;
       continue;
     }
 
@@ -4573,7 +4610,7 @@ bool AsmParser::parseMSInlineAsm(
     default:
       break;
     case AOK_Imm:
-      OS << "$$" << (*I).Val;
+      OS << "$$" << AR.Val;
       break;
     case AOK_ImmPrefix:
       OS << "$$";
@@ -4585,7 +4622,7 @@ bool AsmParser::parseMSInlineAsm(
       OS << '$' << OutputIdx++;
       break;
     case AOK_SizeDirective:
-      switch ((*I).Val) {
+      switch (AR.Val) {
       default: break;
       case 8:  OS << "byte ptr "; break;
       case 16: OS << "word ptr "; break;
@@ -4600,7 +4637,7 @@ bool AsmParser::parseMSInlineAsm(
       OS << ".byte";
       break;
     case AOK_Align: {
-      unsigned Val = (*I).Val;
+      unsigned Val = AR.Val;
       OS << ".align " << Val;
 
       // Skip the original immediate.
@@ -4613,12 +4650,12 @@ bool AsmParser::parseMSInlineAsm(
       OS.flush();
       if (AsmStringIR.back() != '.')
         OS << '.';
-      OS << (*I).Val;
+      OS << AR.Val;
       break;
     }
 
     // Skip the original expression.
-    AsmStart = Loc + (*I).Len + AdditionalSkip;
+    AsmStart = Loc + AR.Len + AdditionalSkip;
   }
 
   // Emit the remainder of the asm string.
diff --git a/lib/MC/MCParser/COFFAsmParser.cpp b/lib/MC/MCParser/COFFAsmParser.cpp
index decf01c..5ecf9e5 100644
--- a/lib/MC/MCParser/COFFAsmParser.cpp
+++ b/lib/MC/MCParser/COFFAsmParser.cpp
@@ -13,6 +13,7 @@
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCObjectFileInfo.h"
 #include "llvm/MC/MCParser/MCAsmLexer.h"
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCSectionCOFF.h"
@@ -37,7 +38,7 @@ class COFFAsmParser : public MCAsmParserExtension {
 
   bool ParseSectionSwitch(StringRef Section, unsigned Characteristics,
                           SectionKind Kind, StringRef COMDATSymName,
-                          COFF::COMDATType Type, const MCSectionCOFF *Assoc);
+                          COFF::COMDATType Type);
 
   bool ParseSectionName(StringRef &SectionName);
   bool ParseSectionFlags(StringRef FlagsString, unsigned* Flags);
@@ -117,8 +118,7 @@ class COFFAsmParser : public MCAsmParserExtension {
   bool ParseDirectiveEndef(StringRef, SMLoc);
   bool ParseDirectiveSecRel32(StringRef, SMLoc);
   bool ParseDirectiveSecIdx(StringRef, SMLoc);
-  bool parseCOMDATTypeAndAssoc(COFF::COMDATType &Type,
-                               const MCSectionCOFF *&Assoc);
+  bool parseCOMDATType(COFF::COMDATType &Type);
   bool ParseDirectiveLinkOnce(StringRef, SMLoc);
 
   // Win64 EH directives.
@@ -170,8 +170,8 @@ bool COFFAsmParser::ParseSectionFlags(StringRef FlagsString, unsigned* Flags) {
   bool ReadOnlyRemoved = false;
   unsigned SecFlags = None;
 
-  for (unsigned i = 0; i < FlagsString.size(); ++i) {
-    switch (FlagsString[i]) {
+  for (char FlagChar : FlagsString) {
+    switch (FlagChar) {
     case 'a':
       // Ignored.
       break;
@@ -292,22 +292,20 @@ bool COFFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
 bool COFFAsmParser::ParseSectionSwitch(StringRef Section,
                                        unsigned Characteristics,
                                        SectionKind Kind) {
-  return ParseSectionSwitch(Section, Characteristics, Kind, "",
-                            COFF::IMAGE_COMDAT_SELECT_ANY, nullptr);
+  return ParseSectionSwitch(Section, Characteristics, Kind, "", (COFF::COMDATType)0);
 }
 
 bool COFFAsmParser::ParseSectionSwitch(StringRef Section,
                                        unsigned Characteristics,
                                        SectionKind Kind,
                                        StringRef COMDATSymName,
-                                       COFF::COMDATType Type,
-                                       const MCSectionCOFF *Assoc) {
+                                       COFF::COMDATType Type) {
   if (getLexer().isNot(AsmToken::EndOfStatement))
     return TokError("unexpected token in section switching directive");
   Lex();
 
   getStreamer().SwitchSection(getContext().getCOFFSection(
-      Section, Characteristics, Kind, COMDATSymName, Type, Assoc));
+      Section, Characteristics, Kind, COMDATSymName, Type));
 
   return false;
 }
@@ -358,15 +356,15 @@ bool COFFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
       return true;
   }
 
-  COFF::COMDATType Type = COFF::IMAGE_COMDAT_SELECT_ANY;
-  const MCSectionCOFF *Assoc = nullptr;
+  COFF::COMDATType Type = (COFF::COMDATType)0;
   StringRef COMDATSymName;
   if (getLexer().is(AsmToken::Comma)) {
+    Type = COFF::IMAGE_COMDAT_SELECT_ANY;;
     Lex();
 
     Flags |= COFF::IMAGE_SCN_LNK_COMDAT;
 
-    if (parseCOMDATTypeAndAssoc(Type, Assoc))
+    if (parseCOMDATType(Type))
       return true;
 
     if (getLexer().isNot(AsmToken::Comma))
@@ -381,7 +379,12 @@ bool COFFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
     return TokError("unexpected token in directive");
 
   SectionKind Kind = computeSectionKind(Flags);
-  ParseSectionSwitch(SectionName, Flags, Kind, COMDATSymName, Type, Assoc);
+  if (Kind.isText()) {
+    const Triple &T = getContext().getObjectFileInfo()->getTargetTriple();
+    if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
+      Flags |= COFF::IMAGE_SCN_MEM_16BIT;
+  }
+  ParseSectionSwitch(SectionName, Flags, Kind, COMDATSymName, Type);
   return false;
 }
 
@@ -461,9 +464,8 @@ bool COFFAsmParser::ParseDirectiveSecIdx(StringRef, SMLoc) {
   return false;
 }
 
-/// ::= [ identifier [ identifier ] ]
-bool COFFAsmParser::parseCOMDATTypeAndAssoc(COFF::COMDATType &Type,
-                                            const MCSectionCOFF *&Assoc) {
+/// ::= [ identifier ]
+bool COFFAsmParser::parseCOMDATType(COFF::COMDATType &Type) {
   StringRef TypeId = getTok().getIdentifier();
 
   Type = StringSwitch<COFF::COMDATType>(TypeId)
@@ -481,48 +483,28 @@ bool COFFAsmParser::parseCOMDATTypeAndAssoc(COFF::COMDATType &Type,
 
   Lex();
 
-  if (Type == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) {
-    SMLoc Loc = getTok().getLoc();
-    StringRef AssocName;
-    if (ParseSectionName(AssocName))
-      return TokError("expected associated section name");
-
-    Assoc = static_cast<const MCSectionCOFF*>(
-                                        getContext().getCOFFSection(AssocName));
-    if (!Assoc)
-      return Error(Loc, "cannot associate unknown section '" + AssocName + "'");
-    if (!(Assoc->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT))
-      return Error(Loc, "associated section must be a COMDAT section");
-    if (Assoc->getSelection() == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
-      return Error(Loc, "associated section cannot be itself associative");
-  }
-
   return false;
 }
 
 /// ParseDirectiveLinkOnce
-///  ::= .linkonce [ identifier [ identifier ] ]
+///  ::= .linkonce [ identifier ]
 bool COFFAsmParser::ParseDirectiveLinkOnce(StringRef, SMLoc Loc) {
   COFF::COMDATType Type = COFF::IMAGE_COMDAT_SELECT_ANY;
-  const MCSectionCOFF *Assoc = nullptr;
   if (getLexer().is(AsmToken::Identifier))
-    if (parseCOMDATTypeAndAssoc(Type, Assoc))
+    if (parseCOMDATType(Type))
       return true;
 
   const MCSectionCOFF *Current = static_cast<const MCSectionCOFF*>(
                                        getStreamer().getCurrentSection().first);
 
-
-  if (Type == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) {
-    if (Assoc == Current)
-      return Error(Loc, "cannot associate a section with itself");
-  }
+  if (Type == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
+    return Error(Loc, "cannot make section associative with .linkonce");
 
   if (Current->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT)
     return Error(Loc, Twine("section '") + Current->getSectionName() +
                                                        "' is already linkonce");
 
-  Current->setSelection(Type, Assoc);
+  Current->setSelection(Type);
 
   if (getLexer().isNot(AsmToken::EndOfStatement))
     return TokError("unexpected token in directive");
@@ -541,25 +523,25 @@ bool COFFAsmParser::ParseSEHDirectiveStartProc(StringRef, SMLoc) {
   MCSymbol *Symbol = getContext().GetOrCreateSymbol(SymbolID);
 
   Lex();
-  getStreamer().EmitWin64EHStartProc(Symbol);
+  getStreamer().EmitWinCFIStartProc(Symbol);
   return false;
 }
 
 bool COFFAsmParser::ParseSEHDirectiveEndProc(StringRef, SMLoc) {
   Lex();
-  getStreamer().EmitWin64EHEndProc();
+  getStreamer().EmitWinCFIEndProc();
   return false;
 }
 
 bool COFFAsmParser::ParseSEHDirectiveStartChained(StringRef, SMLoc) {
   Lex();
-  getStreamer().EmitWin64EHStartChained();
+  getStreamer().EmitWinCFIStartChained();
   return false;
 }
 
 bool COFFAsmParser::ParseSEHDirectiveEndChained(StringRef, SMLoc) {
   Lex();
-  getStreamer().EmitWin64EHEndChained();
+  getStreamer().EmitWinCFIEndChained();
   return false;
 }
 
@@ -585,13 +567,13 @@ bool COFFAsmParser::ParseSEHDirectiveHandler(StringRef, SMLoc) {
   MCSymbol *handler = getContext().GetOrCreateSymbol(SymbolID);
 
   Lex();
-  getStreamer().EmitWin64EHHandler(handler, unwind, except);
+  getStreamer().EmitWinEHHandler(handler, unwind, except);
   return false;
 }
 
 bool COFFAsmParser::ParseSEHDirectiveHandlerData(StringRef, SMLoc) {
   Lex();
-  getStreamer().EmitWin64EHHandlerData();
+  getStreamer().EmitWinEHHandlerData();
   return false;
 }
 
@@ -604,7 +586,7 @@ bool COFFAsmParser::ParseSEHDirectivePushReg(StringRef, SMLoc L) {
     return TokError("unexpected token in directive");
 
   Lex();
-  getStreamer().EmitWin64EHPushReg(Reg);
+  getStreamer().EmitWinCFIPushReg(Reg);
   return false;
 }
 
@@ -628,7 +610,7 @@ bool COFFAsmParser::ParseSEHDirectiveSetFrame(StringRef, SMLoc L) {
     return TokError("unexpected token in directive");
 
   Lex();
-  getStreamer().EmitWin64EHSetFrame(Reg, Off);
+  getStreamer().EmitWinCFISetFrame(Reg, Off);
   return false;
 }
 
@@ -645,7 +627,7 @@ bool COFFAsmParser::ParseSEHDirectiveAllocStack(StringRef, SMLoc) {
     return TokError("unexpected token in directive");
 
   Lex();
-  getStreamer().EmitWin64EHAllocStack(Size);
+  getStreamer().EmitWinCFIAllocStack(Size);
   return false;
 }
 
@@ -670,7 +652,7 @@ bool COFFAsmParser::ParseSEHDirectiveSaveReg(StringRef, SMLoc L) {
 
   Lex();
   // FIXME: Err on %xmm* registers
-  getStreamer().EmitWin64EHSaveReg(Reg, Off);
+  getStreamer().EmitWinCFISaveReg(Reg, Off);
   return false;
 }
 
@@ -697,7 +679,7 @@ bool COFFAsmParser::ParseSEHDirectiveSaveXMM(StringRef, SMLoc L) {
 
   Lex();
   // FIXME: Err on non-%xmm* registers
-  getStreamer().EmitWin64EHSaveXMM(Reg, Off);
+  getStreamer().EmitWinCFISaveXMM(Reg, Off);
   return false;
 }
 
@@ -718,13 +700,13 @@ bool COFFAsmParser::ParseSEHDirectivePushFrame(StringRef, SMLoc) {
     return TokError("unexpected token in directive");
 
   Lex();
-  getStreamer().EmitWin64EHPushFrame(Code);
+  getStreamer().EmitWinCFIPushFrame(Code);
   return false;
 }
 
 bool COFFAsmParser::ParseSEHDirectiveEndProlog(StringRef, SMLoc) {
   Lex();
-  getStreamer().EmitWin64EHEndProlog();
+  getStreamer().EmitWinCFIEndProlog();
   return false;
 }
 
diff --git a/lib/MC/MCParser/DarwinAsmParser.cpp b/lib/MC/MCParser/DarwinAsmParser.cpp
index f74b30a..b2a6785 100644
--- a/lib/MC/MCParser/DarwinAsmParser.cpp
+++ b/lib/MC/MCParser/DarwinAsmParser.cpp
@@ -650,7 +650,7 @@ bool DarwinAsmParser::parseDirectiveSecureLogUnique(StringRef, SMLoc IDLoc) {
   }
 
   // Write the message.
-  int CurBuf = getSourceManager().FindBufferContainingLoc(IDLoc);
+  unsigned CurBuf = getSourceManager().FindBufferContainingLoc(IDLoc);
   *OS << getSourceManager().getBufferInfo(CurBuf).Buffer->getBufferIdentifier()
       << ":" << getSourceManager().FindLineNumber(IDLoc, CurBuf) << ":"
       << LogMessage + "\n";
diff --git a/lib/MC/MCParser/ELFAsmParser.cpp b/lib/MC/MCParser/ELFAsmParser.cpp
index 95c4971..98b2b3b 100644
--- a/lib/MC/MCParser/ELFAsmParser.cpp
+++ b/lib/MC/MCParser/ELFAsmParser.cpp
@@ -150,7 +150,7 @@ public:
 
 private:
   bool ParseSectionName(StringRef &SectionName);
-  bool ParseSectionArguments(bool IsPush);
+  bool ParseSectionArguments(bool IsPush, SMLoc loc);
   unsigned parseSunStyleSectionFlags();
 };
 
@@ -382,7 +382,7 @@ unsigned ELFAsmParser::parseSunStyleSectionFlags() {
 bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
   getStreamer().PushSection();
 
-  if (ParseSectionArguments(/*IsPush=*/true)) {
+  if (ParseSectionArguments(/*IsPush=*/true, loc)) {
     getStreamer().PopSection();
     return true;
   }
@@ -397,11 +397,11 @@ bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
 }
 
 // FIXME: This is a work in progress.
-bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
-  return ParseSectionArguments(/*IsPush=*/false);
+bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc loc) {
+  return ParseSectionArguments(/*IsPush=*/false, loc);
 }
 
-bool ELFAsmParser::ParseSectionArguments(bool IsPush) {
+bool ELFAsmParser::ParseSectionArguments(bool IsPush, SMLoc loc) {
   StringRef SectionName;
 
   if (ParseSectionName(SectionName))
@@ -545,10 +545,24 @@ EndStmt:
   }
 
   SectionKind Kind = computeSectionKind(Flags, Size);
-  getStreamer().SwitchSection(getContext().getELFSection(SectionName, Type,
-                                                         Flags, Kind, Size,
-                                                         GroupName),
-                              Subsection);
+  const MCSection *ELFSection = getContext().getELFSection(
+      SectionName, Type, Flags, Kind, Size, GroupName);
+  getStreamer().SwitchSection(ELFSection, Subsection);
+
+  if (getContext().getGenDwarfForAssembly()) {
+    auto &Sections = getContext().getGenDwarfSectionSyms();
+    auto InsertResult = Sections.insert(
+        std::make_pair(ELFSection, std::make_pair(nullptr, nullptr)));
+    if (InsertResult.second) {
+      if (getContext().getDwarfVersion() <= 2)
+        Error(loc, "DWARF2 only supports one section per compilation unit");
+
+      MCSymbol *SectionStartSymbol = getContext().CreateTempSymbol();
+      getStreamer().EmitLabel(SectionStartSymbol);
+      InsertResult.first->second.first = SectionStartSymbol;
+    }
+  }
+
   return false;
 }
 
@@ -561,6 +575,19 @@ bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
   return false;
 }
 
+static MCSymbolAttr MCAttrForString(StringRef Type) {
+  return StringSwitch<MCSymbolAttr>(Type)
+          .Cases("STT_FUNC", "function", MCSA_ELF_TypeFunction)
+          .Cases("STT_OBJECT", "object", MCSA_ELF_TypeObject)
+          .Cases("STT_TLS", "tls_object", MCSA_ELF_TypeTLS)
+          .Cases("STT_COMMON", "common", MCSA_ELF_TypeCommon)
+          .Cases("STT_NOTYPE", "notype", MCSA_ELF_TypeNoType)
+          .Cases("STT_GNU_IFUNC", "gnu_indirect_function",
+                 MCSA_ELF_TypeIndFunction)
+          .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
+          .Default(MCSA_Invalid);
+}
+
 /// ParseDirectiveELFType
 ///  ::= .type identifier , STT_<TYPE_IN_UPPER_CASE>
 ///  ::= .type identifier , #attribute
@@ -575,53 +602,36 @@ bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) {
   // Handle the identifier as the key symbol.
   MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
 
-  if (getLexer().isNot(AsmToken::Comma))
-    return TokError("unexpected token in '.type' directive");
-  Lex();
-
-  StringRef Type;
-  SMLoc TypeLoc;
-  MCSymbolAttr Attr;
-  if (getLexer().is(AsmToken::Identifier)) {
-    TypeLoc = getLexer().getLoc();
-    if (getParser().parseIdentifier(Type))
-      return TokError("expected symbol type in directive");
-    Attr = StringSwitch<MCSymbolAttr>(Type)
-               .Case("STT_FUNC", MCSA_ELF_TypeFunction)
-               .Case("STT_OBJECT", MCSA_ELF_TypeObject)
-               .Case("STT_TLS", MCSA_ELF_TypeTLS)
-               .Case("STT_COMMON", MCSA_ELF_TypeCommon)
-               .Case("STT_NOTYPE", MCSA_ELF_TypeNoType)
-               .Case("STT_GNU_IFUNC", MCSA_ELF_TypeIndFunction)
-               .Default(MCSA_Invalid);
-  } else if (getLexer().is(AsmToken::Hash) || getLexer().is(AsmToken::At) ||
-             getLexer().is(AsmToken::Percent) ||
-             getLexer().is(AsmToken::String)) {
-    if (!getLexer().is(AsmToken::String))
-      Lex();
+  // NOTE the comma is optional in all cases.  It is only documented as being
+  // optional in the first case, however, GAS will silently treat the comma as
+  // optional in all cases.  Furthermore, although the documentation states that
+  // the first form only accepts STT_<TYPE_IN_UPPER_CASE>, in reality, GAS
+  // accepts both the upper case name as well as the lower case aliases.
+  if (getLexer().is(AsmToken::Comma))
+    Lex();
 
-    TypeLoc = getLexer().getLoc();
-    if (getParser().parseIdentifier(Type))
-      return TokError("expected symbol type in directive");
-    Attr = StringSwitch<MCSymbolAttr>(Type)
-               .Case("function", MCSA_ELF_TypeFunction)
-               .Case("object", MCSA_ELF_TypeObject)
-               .Case("tls_object", MCSA_ELF_TypeTLS)
-               .Case("common", MCSA_ELF_TypeCommon)
-               .Case("notype", MCSA_ELF_TypeNoType)
-               .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
-               .Case("gnu_indirect_function", MCSA_ELF_TypeIndFunction)
-               .Default(MCSA_Invalid);
-  } else
+  if (getLexer().isNot(AsmToken::Identifier) &&
+      getLexer().isNot(AsmToken::Hash) && getLexer().isNot(AsmToken::At) &&
+      getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::String))
     return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '@<type>', "
                     "'%<type>' or \"<type>\"");
 
+  if (getLexer().isNot(AsmToken::String) &&
+      getLexer().isNot(AsmToken::Identifier))
+    Lex();
+
+  SMLoc TypeLoc = getLexer().getLoc();
+
+  StringRef Type;
+  if (getParser().parseIdentifier(Type))
+    return TokError("expected symbol type in directive");
+
+  MCSymbolAttr Attr = MCAttrForString(Type);
   if (Attr == MCSA_Invalid)
     return Error(TypeLoc, "unsupported attribute in '.type' directive");
 
   if (getLexer().isNot(AsmToken::EndOfStatement))
     return TokError("unexpected token in '.type' directive");
-
   Lex();
 
   getStreamer().EmitSymbolAttribute(Sym, Attr);
diff --git a/lib/MC/MCSectionCOFF.cpp b/lib/MC/MCSectionCOFF.cpp
index 335b8cd..fc2bd36 100644
--- a/lib/MC/MCSectionCOFF.cpp
+++ b/lib/MC/MCSectionCOFF.cpp
@@ -30,14 +30,9 @@ bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name,
   return false;
 }
 
-void MCSectionCOFF::setSelection(int Selection,
-                                 const MCSectionCOFF *Assoc) const {
+void MCSectionCOFF::setSelection(int Selection) const {
   assert(Selection != 0 && "invalid COMDAT selection type");
-  assert((Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) ==
-         (Assoc != nullptr) &&
-    "associative COMDAT section must have an associated section");
   this->Selection = Selection;
-  this->Assoc = Assoc;
   Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
 }
 
@@ -82,7 +77,7 @@ void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI,
         OS << "same_contents,";
         break;
       case COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
-        OS << "associative " << Assoc->getSectionName() << ",";
+        OS << "associative,";
         break;
       case COFF::IMAGE_COMDAT_SELECT_LARGEST:
         OS << "largest,";
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index 7dccf0d..bdcdb97 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/lib/MC/MCStreamer.cpp
@@ -37,7 +37,7 @@ void MCTargetStreamer::finish() {}
 void MCTargetStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {}
 
 MCStreamer::MCStreamer(MCContext &Ctx)
-    : Context(Ctx), CurrentW64UnwindInfo(nullptr), LastSymbol(nullptr) {
+    : Context(Ctx), CurrentW64UnwindInfo(nullptr) {
   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
 }
 
@@ -51,7 +51,6 @@ void MCStreamer::reset() {
     delete W64UnwindInfos[i];
   W64UnwindInfos.clear();
   CurrentW64UnwindInfo = nullptr;
-  LastSymbol = nullptr;
   SectionStack.clear();
   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
 }
@@ -234,20 +233,12 @@ void MCStreamer::EmitLabel(MCSymbol *Symbol) {
   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
   assert(getCurrentSection().first && "Cannot emit before setting section!");
   AssignSection(Symbol, getCurrentSection().first);
-  LastSymbol = Symbol;
 
   MCTargetStreamer *TS = getTargetStreamer();
   if (TS)
     TS->emitLabel(Symbol);
 }
 
-void MCStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
-  assert(getCurrentSection().first && "Cannot emit before setting section!");
-  AssignSection(Symbol, getCurrentSection().first);
-  LastSymbol = Symbol;
-}
-
 void MCStreamer::EmitCompactUnwindEncoding(uint32_t CompactUnwindEncoding) {
   EnsureValidFrame();
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
@@ -273,17 +264,6 @@ void MCStreamer::EmitCFIStartProc(bool IsSimple) {
 void MCStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
 }
 
-void MCStreamer::RecordProcStart(MCDwarfFrameInfo &Frame) {
-  // Report an error if we haven't seen a symbol yet where we'd bind
-  // .cfi_startproc.
-  if (!LastSymbol)
-    report_fatal_error("No symbol to start a frame");
-  Frame.Function = LastSymbol;
-  // We need to create a local symbol to avoid relocations.
-  Frame.Begin = getContext().CreateTempSymbol();
-  EmitLabel(Frame.Begin);
-}
-
 void MCStreamer::EmitCFIEndProc() {
   EnsureValidFrame();
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
@@ -291,11 +271,9 @@ void MCStreamer::EmitCFIEndProc() {
 }
 
 void MCStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
-}
-
-void MCStreamer::RecordProcEnd(MCDwarfFrameInfo &Frame) {
-  Frame.End = getContext().CreateTempSymbol();
-  EmitLabel(Frame.End);
+  // Put a dummy non-null value in Frame.End to mark that this frame has been
+  // closed.
+  Frame.End = (MCSymbol *) 1;
 }
 
 MCSymbol *MCStreamer::EmitCFICommon() {
@@ -447,7 +425,7 @@ void MCStreamer::EnsureValidW64UnwindInfo() {
     report_fatal_error("No open Win64 EH frame function!");
 }
 
-void MCStreamer::EmitWin64EHStartProc(const MCSymbol *Symbol) {
+void MCStreamer::EmitWinCFIStartProc(const MCSymbol *Symbol) {
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
   if (CurFrame && !CurFrame->End)
     report_fatal_error("Starting a function before ending the previous one!");
@@ -458,7 +436,7 @@ void MCStreamer::EmitWin64EHStartProc(const MCSymbol *Symbol) {
   setCurrentW64UnwindInfo(Frame);
 }
 
-void MCStreamer::EmitWin64EHEndProc() {
+void MCStreamer::EmitWinCFIEndProc() {
   EnsureValidW64UnwindInfo();
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
   if (CurFrame->ChainedParent)
@@ -467,7 +445,7 @@ void MCStreamer::EmitWin64EHEndProc() {
   EmitLabel(CurFrame->End);
 }
 
-void MCStreamer::EmitWin64EHStartChained() {
+void MCStreamer::EmitWinCFIStartChained() {
   EnsureValidW64UnwindInfo();
   MCWin64EHUnwindInfo *Frame = new MCWin64EHUnwindInfo;
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
@@ -478,7 +456,7 @@ void MCStreamer::EmitWin64EHStartChained() {
   setCurrentW64UnwindInfo(Frame);
 }
 
-void MCStreamer::EmitWin64EHEndChained() {
+void MCStreamer::EmitWinCFIEndChained() {
   EnsureValidW64UnwindInfo();
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
   if (!CurFrame->ChainedParent)
@@ -488,8 +466,8 @@ void MCStreamer::EmitWin64EHEndChained() {
   CurrentW64UnwindInfo = CurFrame->ChainedParent;
 }
 
-void MCStreamer::EmitWin64EHHandler(const MCSymbol *Sym, bool Unwind,
-                                    bool Except) {
+void MCStreamer::EmitWinEHHandler(const MCSymbol *Sym, bool Unwind,
+                                  bool Except) {
   EnsureValidW64UnwindInfo();
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
   if (CurFrame->ChainedParent)
@@ -503,14 +481,14 @@ void MCStreamer::EmitWin64EHHandler(const MCSymbol *Sym, bool Unwind,
     CurFrame->HandlesExceptions = true;
 }
 
-void MCStreamer::EmitWin64EHHandlerData() {
+void MCStreamer::EmitWinEHHandlerData() {
   EnsureValidW64UnwindInfo();
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
   if (CurFrame->ChainedParent)
     report_fatal_error("Chained unwind areas can't have handlers!");
 }
 
-void MCStreamer::EmitWin64EHPushReg(unsigned Register) {
+void MCStreamer::EmitWinCFIPushReg(unsigned Register) {
   EnsureValidW64UnwindInfo();
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
   MCSymbol *Label = getContext().CreateTempSymbol();
@@ -519,13 +497,15 @@ void MCStreamer::EmitWin64EHPushReg(unsigned Register) {
   CurFrame->Instructions.push_back(Inst);
 }
 
-void MCStreamer::EmitWin64EHSetFrame(unsigned Register, unsigned Offset) {
+void MCStreamer::EmitWinCFISetFrame(unsigned Register, unsigned Offset) {
   EnsureValidW64UnwindInfo();
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
   if (CurFrame->LastFrameInst >= 0)
     report_fatal_error("Frame register and offset already specified!");
   if (Offset & 0x0F)
     report_fatal_error("Misaligned frame pointer offset!");
+  if (Offset > 240)
+    report_fatal_error("Frame offset must be less than or equal to 240!");
   MCSymbol *Label = getContext().CreateTempSymbol();
   MCWin64EHInstruction Inst(Win64EH::UOP_SetFPReg, Label, Register, Offset);
   EmitLabel(Label);
@@ -533,8 +513,10 @@ void MCStreamer::EmitWin64EHSetFrame(unsigned Register, unsigned Offset) {
   CurFrame->Instructions.push_back(Inst);
 }
 
-void MCStreamer::EmitWin64EHAllocStack(unsigned Size) {
+void MCStreamer::EmitWinCFIAllocStack(unsigned Size) {
   EnsureValidW64UnwindInfo();
+  if (Size == 0)
+    report_fatal_error("Allocation size must be non-zero!");
   if (Size & 7)
     report_fatal_error("Misaligned stack allocation!");
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
@@ -544,7 +526,7 @@ void MCStreamer::EmitWin64EHAllocStack(unsigned Size) {
   CurFrame->Instructions.push_back(Inst);
 }
 
-void MCStreamer::EmitWin64EHSaveReg(unsigned Register, unsigned Offset) {
+void MCStreamer::EmitWinCFISaveReg(unsigned Register, unsigned Offset) {
   EnsureValidW64UnwindInfo();
   if (Offset & 7)
     report_fatal_error("Misaligned saved register offset!");
@@ -557,7 +539,7 @@ void MCStreamer::EmitWin64EHSaveReg(unsigned Register, unsigned Offset) {
   CurFrame->Instructions.push_back(Inst);
 }
 
-void MCStreamer::EmitWin64EHSaveXMM(unsigned Register, unsigned Offset) {
+void MCStreamer::EmitWinCFISaveXMM(unsigned Register, unsigned Offset) {
   EnsureValidW64UnwindInfo();
   if (Offset & 0x0F)
     report_fatal_error("Misaligned saved vector register offset!");
@@ -570,7 +552,7 @@ void MCStreamer::EmitWin64EHSaveXMM(unsigned Register, unsigned Offset) {
   CurFrame->Instructions.push_back(Inst);
 }
 
-void MCStreamer::EmitWin64EHPushFrame(bool Code) {
+void MCStreamer::EmitWinCFIPushFrame(bool Code) {
   EnsureValidW64UnwindInfo();
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
   if (CurFrame->Instructions.size() > 0)
@@ -581,7 +563,7 @@ void MCStreamer::EmitWin64EHPushFrame(bool Code) {
   CurFrame->Instructions.push_back(Inst);
 }
 
-void MCStreamer::EmitWin64EHEndProlog() {
+void MCStreamer::EmitWinCFIEndProlog() {
   EnsureValidW64UnwindInfo();
   MCWin64EHUnwindInfo *CurFrame = CurrentW64UnwindInfo;
   CurFrame->PrologEnd = getContext().CreateTempSymbol();
@@ -589,11 +571,9 @@ void MCStreamer::EmitWin64EHEndProlog() {
 }
 
 void MCStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
-  llvm_unreachable("This file format doesn't support this directive");
 }
 
 void MCStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
-  llvm_unreachable("This file format doesn't support this directive");
 }
 
 /// EmitRawText - If this file is backed by an assembly streamer, this dumps
@@ -629,9 +609,82 @@ void MCStreamer::Finish() {
 }
 
 void MCStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
+  visitUsedExpr(*Value);
   Symbol->setVariableValue(Value);
 
   MCTargetStreamer *TS = getTargetStreamer();
   if (TS)
     TS->emitAssignment(Symbol, Value);
 }
+
+void MCStreamer::visitUsedSymbol(const MCSymbol &Sym) {
+}
+
+void MCStreamer::visitUsedExpr(const MCExpr &Expr) {
+  switch (Expr.getKind()) {
+  case MCExpr::Target:
+    cast<MCTargetExpr>(Expr).visitUsedExpr(*this);
+    break;
+
+  case MCExpr::Constant:
+    break;
+
+  case MCExpr::Binary: {
+    const MCBinaryExpr &BE = cast<MCBinaryExpr>(Expr);
+    visitUsedExpr(*BE.getLHS());
+    visitUsedExpr(*BE.getRHS());
+    break;
+  }
+
+  case MCExpr::SymbolRef:
+    visitUsedSymbol(cast<MCSymbolRefExpr>(Expr).getSymbol());
+    break;
+
+  case MCExpr::Unary:
+    visitUsedExpr(*cast<MCUnaryExpr>(Expr).getSubExpr());
+    break;
+  }
+}
+
+void MCStreamer::EmitInstruction(const MCInst &Inst,
+                                 const MCSubtargetInfo &STI) {
+  // Scan for values.
+  for (unsigned i = Inst.getNumOperands(); i--;)
+    if (Inst.getOperand(i).isExpr())
+      visitUsedExpr(*Inst.getOperand(i).getExpr());
+}
+
+void MCStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {}
+void MCStreamer::EmitThumbFunc(MCSymbol *Func) {}
+void MCStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
+void MCStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {}
+void MCStreamer::EndCOFFSymbolDef() {}
+void MCStreamer::EmitFileDirective(StringRef Filename) {}
+void MCStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {}
+void MCStreamer::EmitCOFFSymbolType(int Type) {}
+void MCStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
+void MCStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                       unsigned ByteAlignment) {}
+void MCStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
+                                uint64_t Size, unsigned ByteAlignment) {}
+void MCStreamer::ChangeSection(const MCSection *, const MCExpr *) {}
+void MCStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {}
+void MCStreamer::EmitBytes(StringRef Data) {}
+void MCStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
+                               const SMLoc &Loc) {
+  visitUsedExpr(*Value);
+}
+void MCStreamer::EmitULEB128Value(const MCExpr *Value) {}
+void MCStreamer::EmitSLEB128Value(const MCExpr *Value) {}
+void MCStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
+                                      unsigned ValueSize,
+                                      unsigned MaxBytesToEmit) {}
+void MCStreamer::EmitCodeAlignment(unsigned ByteAlignment,
+                                   unsigned MaxBytesToEmit) {}
+bool MCStreamer::EmitValueToOffset(const MCExpr *Offset, unsigned char Value) {
+  return false;
+}
+void MCStreamer::EmitBundleAlignMode(unsigned AlignPow2) {}
+void MCStreamer::EmitBundleLock(bool AlignToEnd) {}
+void MCStreamer::FinishImpl() {}
+void MCStreamer::EmitBundleUnlock() {}
diff --git a/lib/MC/MCTargetOptions.cpp b/lib/MC/MCTargetOptions.cpp
index 8e946d5..efd724a 100644
--- a/lib/MC/MCTargetOptions.cpp
+++ b/lib/MC/MCTargetOptions.cpp
@@ -14,6 +14,7 @@ namespace llvm {
 MCTargetOptions::MCTargetOptions()
     : SanitizeAddress(false), MCRelaxAll(false), MCNoExecStack(false),
       MCSaveTempLabels(false), MCUseDwarfDirectory(false),
-      ShowMCEncoding(false), ShowMCInst(false), AsmVerbose(false) {}
+      ShowMCEncoding(false), ShowMCInst(false), AsmVerbose(false),
+      DwarfVersion(0) {}
 
 } // end namespace llvm
diff --git a/lib/MC/MCWin64EH.cpp b/lib/MC/MCWin64EH.cpp
index b8b07d3..bb651647 100644
--- a/lib/MC/MCWin64EH.cpp
+++ b/lib/MC/MCWin64EH.cpp
@@ -20,34 +20,30 @@ namespace llvm {
 
 // NOTE: All relocations generated here are 4-byte image-relative.
 
-static uint8_t CountOfUnwindCodes(std::vector<MCWin64EHInstruction> &instArray){
-  uint8_t count = 0;
-  for (std::vector<MCWin64EHInstruction>::const_iterator I = instArray.begin(),
-       E = instArray.end(); I != E; ++I) {
-    switch (I->getOperation()) {
+static uint8_t CountOfUnwindCodes(std::vector<MCWin64EHInstruction> &Insns) {
+  uint8_t Count = 0;
+  for (const auto &I : Insns) {
+    switch (I.getOperation()) {
     case Win64EH::UOP_PushNonVol:
     case Win64EH::UOP_AllocSmall:
     case Win64EH::UOP_SetFPReg:
     case Win64EH::UOP_PushMachFrame:
-      count += 1;
+      Count += 1;
       break;
     case Win64EH::UOP_SaveNonVol:
     case Win64EH::UOP_SaveXMM128:
-      count += 2;
+      Count += 2;
       break;
     case Win64EH::UOP_SaveNonVolBig:
     case Win64EH::UOP_SaveXMM128Big:
-      count += 3;
+      Count += 3;
       break;
     case Win64EH::UOP_AllocLarge:
-      if (I->getSize() > 512*1024-8)
-        count += 3;
-      else
-        count += 2;
+      Count += (I.getSize() > 512 * 1024 - 8) ? 3 : 2;
       break;
     }
   }
-  return count;
+  return Count;
 }
 
 static void EmitAbsDifference(MCStreamer &streamer, MCSymbol *lhs,
@@ -274,23 +270,23 @@ void MCWin64EHUnwindEmitter::EmitUnwindInfo(MCStreamer &streamer,
   llvm::EmitUnwindInfo(streamer, info);
 }
 
-void MCWin64EHUnwindEmitter::Emit(MCStreamer &streamer) {
-  MCContext &context = streamer.getContext();
+void MCWin64EHUnwindEmitter::Emit(MCStreamer &Streamer) {
+  MCContext &Context = Streamer.getContext();
+
   // Emit the unwind info structs first.
-  for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i) {
-    MCWin64EHUnwindInfo &info = streamer.getW64UnwindInfo(i);
-    const MCSection *xdataSect =
-      getWin64EHTableSection(GetSectionSuffix(info.Function), context);
-    streamer.SwitchSection(xdataSect);
-    llvm::EmitUnwindInfo(streamer, &info);
+  for (const auto &CFI : Streamer.getW64UnwindInfos()) {
+    const MCSection *XData =
+        getWin64EHTableSection(GetSectionSuffix(CFI->Function), Context);
+    Streamer.SwitchSection(XData);
+    EmitUnwindInfo(Streamer, CFI);
   }
+
   // Now emit RUNTIME_FUNCTION entries.
-  for (unsigned i = 0; i < streamer.getNumW64UnwindInfos(); ++i) {
-    MCWin64EHUnwindInfo &info = streamer.getW64UnwindInfo(i);
-    const MCSection *pdataSect =
-      getWin64EHFuncTableSection(GetSectionSuffix(info.Function), context);
-    streamer.SwitchSection(pdataSect);
-    EmitRuntimeFunction(streamer, &info);
+  for (const auto &CFI : Streamer.getW64UnwindInfos()) {
+    const MCSection *PData =
+        getWin64EHFuncTableSection(GetSectionSuffix(CFI->Function), Context);
+    Streamer.SwitchSection(PData);
+    EmitRuntimeFunction(Streamer, CFI);
   }
 }
 
diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
index cbaf0b8..5214398 100644
--- a/lib/MC/MachObjectWriter.cpp
+++ b/lib/MC/MachObjectWriter.cpp
@@ -303,20 +303,50 @@ void MachObjectWriter::WriteDysymtabLoadCommand(uint32_t FirstLocalSymbol,
   assert(OS.tell() - Start == sizeof(MachO::dysymtab_command));
 }
 
+MachObjectWriter::MachSymbolData *
+MachObjectWriter::findSymbolData(const MCSymbol &Sym) {
+  for (auto &Entry : LocalSymbolData)
+    if (&Entry.SymbolData->getSymbol() == &Sym)
+      return &Entry;
+
+  for (auto &Entry : ExternalSymbolData)
+    if (&Entry.SymbolData->getSymbol() == &Sym)
+      return &Entry;
+
+  for (auto &Entry : UndefinedSymbolData)
+    if (&Entry.SymbolData->getSymbol() == &Sym)
+      return &Entry;
+
+  return nullptr;
+}
+
 void MachObjectWriter::WriteNlist(MachSymbolData &MSD,
                                   const MCAsmLayout &Layout) {
   MCSymbolData &Data = *MSD.SymbolData;
-  const MCSymbol &Symbol = Data.getSymbol();
+  const MCSymbol *Symbol = &Data.getSymbol();
+  const MCSymbol *AliasedSymbol = &Symbol->AliasedSymbol();
+  uint8_t SectionIndex = MSD.SectionIndex;
   uint8_t Type = 0;
   uint16_t Flags = Data.getFlags();
   uint64_t Address = 0;
+  bool IsAlias = Symbol != AliasedSymbol;
+
+  MachSymbolData *AliaseeInfo;
+  if (IsAlias) {
+    AliaseeInfo = findSymbolData(*AliasedSymbol);
+    if (AliaseeInfo)
+      SectionIndex = AliaseeInfo->SectionIndex;
+    Symbol = AliasedSymbol;
+  }
 
   // Set the N_TYPE bits. See <mach-o/nlist.h>.
   //
   // FIXME: Are the prebound or indirect fields possible here?
-  if (Symbol.isUndefined())
+  if (IsAlias && Symbol->isUndefined())
+    Type = MachO::N_INDR;
+  else if (Symbol->isUndefined())
     Type = MachO::N_UNDF;
-  else if (Symbol.isAbsolute())
+  else if (Symbol->isAbsolute())
     Type = MachO::N_ABS;
   else
     Type = MachO::N_SECT;
@@ -327,13 +357,15 @@ void MachObjectWriter::WriteNlist(MachSymbolData &MSD,
     Type |= MachO::N_PEXT;
 
   // Set external bit.
-  if (Data.isExternal() || Symbol.isUndefined())
+  if (Data.isExternal() || (!IsAlias && Symbol->isUndefined()))
     Type |= MachO::N_EXT;
 
   // Compute the symbol address.
-  if (Symbol.isDefined()) {
+  if (IsAlias && Symbol->isUndefined())
+    Address = AliaseeInfo->StringIndex;
+  else if (Symbol->isDefined())
     Address = getSymbolAddress(&Data, Layout);
-  } else if (Data.isCommon()) {
+  else if (Data.isCommon()) {
     // Common symbols are encoded with the size in the address
     // field, and their alignment in the flags.
     Address = Data.getCommonSize();
@@ -344,21 +376,21 @@ void MachObjectWriter::WriteNlist(MachSymbolData &MSD,
       assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
       if (Log2Size > 15)
         report_fatal_error("invalid 'common' alignment '" +
-                           Twine(Align) + "' for '" + Symbol.getName() + "'",
+                           Twine(Align) + "' for '" + Symbol->getName() + "'",
                            false);
       // FIXME: Keep this mask with the SymbolFlags enumeration.
       Flags = (Flags & 0xF0FF) | (Log2Size << 8);
     }
   }
 
-  if (Layout.getAssembler().isThumbFunc(&Symbol))
+  if (Layout.getAssembler().isThumbFunc(Symbol))
     Flags |= SF_ThumbFunc;
 
   // struct nlist (12 bytes)
 
   Write32(MSD.StringIndex);
   Write8(Type);
-  Write8(MSD.SectionIndex);
+  Write8(SectionIndex);
 
   // The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
   // value.
diff --git a/lib/MC/Makefile b/lib/MC/Makefile
index bf8b7c0..a10f17e 100644
--- a/lib/MC/Makefile
+++ b/lib/MC/Makefile
@@ -10,7 +10,7 @@
 LEVEL = ../..
 LIBRARYNAME = LLVMMC
 BUILD_ARCHIVE := 1
-PARALLEL_DIRS := MCParser MCDisassembler
+PARALLEL_DIRS := MCAnalysis MCParser MCDisassembler
 
 include $(LEVEL)/Makefile.common
 
diff --git a/lib/MC/StringTableBuilder.cpp b/lib/MC/StringTableBuilder.cpp
new file mode 100644
index 0000000..db58ece
--- /dev/null
+++ b/lib/MC/StringTableBuilder.cpp
@@ -0,0 +1,51 @@
+//===-- StringTableBuilder.cpp - String table building utility ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/StringTableBuilder.h"
+#include "llvm/ADT/SmallVector.h"
+
+using namespace llvm;
+
+static bool compareBySuffix(StringRef a, StringRef b) {
+  size_t sizeA = a.size();
+  size_t sizeB = b.size();
+  size_t len = std::min(sizeA, sizeB);
+  for (size_t i = 0; i < len; ++i) {
+    char ca = a[sizeA - i - 1];
+    char cb = b[sizeB - i - 1];
+    if (ca != cb)
+      return ca > cb;
+  }
+  return sizeA > sizeB;
+}
+
+void StringTableBuilder::finalize() {
+  SmallVector<StringRef, 8> Strings;
+  for (auto i = StringIndexMap.begin(), e = StringIndexMap.end(); i != e; ++i)
+    Strings.push_back(i->getKey());
+
+  std::sort(Strings.begin(), Strings.end(), compareBySuffix);
+
+  // FIXME: Starting with a null byte is ELF specific. Generalize this so we
+  // can use the class with other object formats.
+  StringTable += '\x00';
+
+  StringRef Previous;
+  for (StringRef s : Strings) {
+    if (Previous.endswith(s)) {
+      StringIndexMap[s] = StringTable.size() - 1 - s.size();
+      continue;
+    }
+
+    StringIndexMap[s] = StringTable.size();
+    StringTable += s;
+    StringTable += '\x00';
+    Previous = s;
+  }
+}
diff --git a/lib/MC/WinCOFFObjectWriter.cpp b/lib/MC/WinCOFFObjectWriter.cpp
index 961cbc6..a462c0d 100644
--- a/lib/MC/WinCOFFObjectWriter.cpp
+++ b/lib/MC/WinCOFFObjectWriter.cpp
@@ -347,6 +347,14 @@ void WinCOFFObjectWriter::DefineSection(MCSectionData const &SectionData) {
 
   COFFSection *coff_section = createSection(Sec.getSectionName());
   COFFSymbol  *coff_symbol = createSymbol(Sec.getSectionName());
+  if (Sec.getSelection() != COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) {
+    if (const MCSymbol *S = Sec.getCOMDATSymbol()) {
+      COFFSymbol *COMDATSymbol = GetOrCreateCOFFSymbol(S);
+      if (COMDATSymbol->Section)
+        report_fatal_error("two sections have the same comdat");
+      COMDATSymbol->Section = coff_section;
+    }
+  }
 
   coff_section->Symbol = coff_symbol;
   coff_symbol->Section = coff_section;
@@ -458,9 +466,15 @@ void WinCOFFObjectWriter::DefineSymbol(MCSymbolData const &SymbolData,
       coff_symbol->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;
     } else {
       const MCSymbolData &BaseData = Assembler.getSymbolData(*Base);
-      if (BaseData.Fragment)
-        coff_symbol->Section =
+      if (BaseData.Fragment) {
+        COFFSection *Sec =
             SectionMap[&BaseData.Fragment->getParent()->getSection()];
+
+        if (coff_symbol->Section && coff_symbol->Section != Sec)
+          report_fatal_error("conflicting sections for symbol");
+
+        coff_symbol->Section = Sec;
+      }
     }
 
     coff_symbol->MCData = &ResSymData;
@@ -537,7 +551,7 @@ bool WinCOFFObjectWriter::ExportSymbol(MCSymbolData const &SymbolData,
   // This doesn't seem to be right. Strings referred to from the .data section
   // need symbols so they can be linked to code in the .text section right?
 
-  // return Asm.isSymbolLinkerVisible (&SymbolData);
+  // return Asm.isSymbolLinkerVisible(SymbolData.getSymbol());
 
   // For now, all non-variable symbols are exported,
   // the linker will sort the rest out for us.
@@ -819,13 +833,9 @@ void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
 
   DenseMap<COFFSection *, uint16_t> SectionIndices;
   for (auto & Section : Sections) {
-    if (Layout.getSectionAddressSize(Section->MCData) > 0) {
-      size_t Number = ++Header.NumberOfSections;
-      SectionIndices[Section.get()] = Number;
-      MakeSectionReal(*Section, Number);
-    } else {
-      Section->Number = -1;
-    }
+    size_t Number = ++Header.NumberOfSections;
+    SectionIndices[Section.get()] = Number;
+    MakeSectionReal(*Section, Number);
   }
 
   Header.NumberOfSymbols = 0;
@@ -865,11 +875,15 @@ void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
     const MCSectionCOFF &MCSec =
       static_cast<const MCSectionCOFF &>(Section->MCData->getSection());
 
-    COFFSection *Assoc = SectionMap.lookup(MCSec.getAssocSection());
+    const MCSymbol *COMDAT = MCSec.getCOMDATSymbol();
+    assert(COMDAT);
+    COFFSymbol *COMDATSymbol = GetOrCreateCOFFSymbol(COMDAT);
+    assert(COMDATSymbol);
+    COFFSection *Assoc = COMDATSymbol->Section;
     if (!Assoc)
-      report_fatal_error(Twine("Missing associated COMDAT section ") +
-                         MCSec.getAssocSection()->getSectionName() +
-                         " for section " + MCSec.getSectionName());
+      report_fatal_error(
+          Twine("Missing associated COMDAT section for section ") +
+          MCSec.getSectionName());
 
     // Skip this section if the associated section is unused.
     if (Assoc->Number == -1)
diff --git a/lib/MC/WinCOFFStreamer.cpp b/lib/MC/WinCOFFStreamer.cpp
index e6df465..d391a3f 100644
--- a/lib/MC/WinCOFFStreamer.cpp
+++ b/lib/MC/WinCOFFStreamer.cpp
@@ -82,10 +82,6 @@ void MCWinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
   MCObjectStreamer::EmitLabel(Symbol);
 }
 
-void MCWinCOFFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
-  EmitLabel(Symbol);
-}
-
 void MCWinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   llvm_unreachable("not implemented");
 }
@@ -242,7 +238,7 @@ void MCWinCOFFStreamer::EmitIdent(StringRef IdentString) {
   llvm_unreachable("not implemented");
 }
 
-void MCWinCOFFStreamer::EmitWin64EHHandlerData() {
+void MCWinCOFFStreamer::EmitWinEHHandlerData() {
   llvm_unreachable("not implemented");
 }
 
diff --git a/lib/MC/YAML.cpp b/lib/MC/YAML.cpp
new file mode 100644
index 0000000..067e91a
--- /dev/null
+++ b/lib/MC/YAML.cpp
@@ -0,0 +1,65 @@
+//===- YAML.cpp - YAMLIO utilities for object files -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines utility classes for handling the YAML representation of
+// object files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/YAML.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cctype>
+
+using namespace llvm;
+
+void yaml::ScalarTraits<yaml::BinaryRef>::output(
+    const yaml::BinaryRef &Val, void *, llvm::raw_ostream &Out) {
+  Val.writeAsHex(Out);
+}
+
+StringRef yaml::ScalarTraits<yaml::BinaryRef>::input(StringRef Scalar, void *,
+                                                     yaml::BinaryRef &Val) {
+  if (Scalar.size() % 2 != 0)
+    return "BinaryRef hex string must contain an even number of nybbles.";
+  // TODO: Can we improve YAMLIO to permit a more accurate diagnostic here?
+  // (e.g. a caret pointing to the offending character).
+  for (unsigned I = 0, N = Scalar.size(); I != N; ++I)
+    if (!isxdigit(Scalar[I]))
+      return "BinaryRef hex string must contain only hex digits.";
+  Val = yaml::BinaryRef(Scalar);
+  return StringRef();
+}
+
+void yaml::BinaryRef::writeAsBinary(raw_ostream &OS) const {
+  if (!DataIsHexString) {
+    OS.write((const char *)Data.data(), Data.size());
+    return;
+  }
+  for (unsigned I = 0, N = Data.size(); I != N; I += 2) {
+    uint8_t Byte;
+    StringRef((const char *)&Data[I],  2).getAsInteger(16, Byte);
+    OS.write(Byte);
+  }
+}
+
+void yaml::BinaryRef::writeAsHex(raw_ostream &OS) const {
+  if (binary_size() == 0)
+    return;
+  if (DataIsHexString) {
+    OS.write((const char *)Data.data(), Data.size());
+    return;
+  }
+  for (ArrayRef<uint8_t>::iterator I = Data.begin(), E = Data.end(); I != E;
+       ++I) {
+    uint8_t Byte = *I;
+    OS << hexdigit(Byte >> 4);
+    OS << hexdigit(Byte & 0xf);
+  }
+}