Refactor data-in-code annotations.

Use a dedicated MachO load command to annotate data-in-code regions.
This is the same format the linker produces for final executable images,
allowing consistency of representation and use of introspection tools
for both object and executable files.

Data-in-code regions are annotated via ".data_region"/".end_data_region"
directive pairs, with an optional region type.

data_region_directive := ".data_region" { region_type }
region_type := "jt8" | "jt16" | "jt32" | "jta32"
end_data_region_directive := ".end_data_region"

The previous handling of ARM-style "$d.*" labels was broken and has
been removed. Specifically, it didn't handle ARM vs. Thumb mode when
marking the end of the section.

rdar://11459456

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157062 91177308-0d34-0410-b5e6-96231b3b80d8

15 files changed, 212 insertions, 140 deletions

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index b0b2ff4..ae498dd 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -475,10 +475,8 @@ void AsmPrinter::EmitFunctionHeader() {
 void AsmPrinter::EmitFunctionEntryLabel() {
   // The function label could have already been emitted if two symbols end up
   // conflicting due to asm renaming.  Detect this and emit an error.
-  if (CurrentFnSym->isUndefined()) {
-    OutStreamer.ForceCodeRegion();
+  if (CurrentFnSym->isUndefined())
     return OutStreamer.EmitLabel(CurrentFnSym);
-  }
 
   report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
                      "' label emitted multiple times to assembly file");
@@ -1085,15 +1083,6 @@ void AsmPrinter::EmitJumpTableInfo() {
 
   EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
 
-  // If we know the form of the jump table, go ahead and tag it as such.
-  if (!JTInDiffSection) {
-    if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32) {
-      OutStreamer.EmitJumpTable32Region();
-    } else {
-      OutStreamer.EmitDataRegion();
-    }
-  }
-
   for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
     const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
 
diff --git a/lib/MC/MCAsmInfo.cpp b/lib/MC/MCAsmInfo.cpp
index 2456858..d9c1d51 100644
--- a/lib/MC/MCAsmInfo.cpp
+++ b/lib/MC/MCAsmInfo.cpp
@@ -50,6 +50,7 @@ MCAsmInfo::MCAsmInfo() {
   AllowNameToStartWithDigit = false;
   AllowPeriodsInName = true;
   AllowUTF8 = true;
+  UseDataRegionDirectives = false;
   ZeroDirective = "\t.zero\t";
   AsciiDirective = "\t.ascii\t";
   AscizDirective = "\t.asciz\t";
@@ -57,12 +58,6 @@ MCAsmInfo::MCAsmInfo() {
   Data16bitsDirective = "\t.short\t";
   Data32bitsDirective = "\t.long\t";
   Data64bitsDirective = "\t.quad\t";
-  DataBegin = "$d.";
-  CodeBegin = "$a.";
-  JT8Begin = "$d.";
-  JT16Begin = "$d.";
-  JT32Begin = "$d.";
-  SupportsDataRegions = false;
   SunStyleELFSectionSwitchSyntax = false;
   UsesELFSectionDirectiveForBSS = false;
   AlignDirective = "\t.align\t";
diff --git a/lib/MC/MCAsmInfoCOFF.cpp b/lib/MC/MCAsmInfoCOFF.cpp
index 8941365..678e75a 100644
--- a/lib/MC/MCAsmInfoCOFF.cpp
+++ b/lib/MC/MCAsmInfoCOFF.cpp
@@ -36,8 +36,6 @@ MCAsmInfoCOFF::MCAsmInfoCOFF() {
   SupportsDebugInformation = true;
   DwarfSectionOffsetDirective = "\t.secrel32\t";
   HasMicrosoftFastStdCallMangling = true;
-
-  SupportsDataRegions = false;
 }
 
 void MCAsmInfoMicrosoft::anchor() { }
diff --git a/lib/MC/MCAsmInfoDarwin.cpp b/lib/MC/MCAsmInfoDarwin.cpp
index 4d67592..73ef7ba 100644
--- a/lib/MC/MCAsmInfoDarwin.cpp
+++ b/lib/MC/MCAsmInfoDarwin.cpp
@@ -43,13 +43,6 @@ MCAsmInfoDarwin::MCAsmInfoDarwin() {
   HasMachoTBSSDirective = true; // Uses .tbss
   HasStaticCtorDtorReferenceInStaticMode = true;
 
-  CodeBegin = "L$start$code$";
-  DataBegin = "L$start$data$";
-  JT8Begin  = "L$start$jt8$";
-  JT16Begin = "L$start$jt16$";
-  JT32Begin = "L$start$jt32$";
-  SupportsDataRegions = true;
-
   // FIXME: Darwin 10 and newer don't need this.
   LinkerRequiresNonEmptyDwarfLines = true;
 
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 3ce84c2..9497b6b 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -138,6 +138,7 @@ public:
   virtual void EmitEHSymAttributes(const MCSymbol *Symbol,
                                    MCSymbol *EHSymbol);
   virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
+  virtual void EmitDataRegion(MCDataRegionType Kind);
   virtual void EmitThumbFunc(MCSymbol *Func);
 
   virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
@@ -352,6 +353,21 @@ void MCAsmStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   EmitEOL();
 }
 
+void MCAsmStreamer::EmitDataRegion(MCDataRegionType Kind) {
+  MCContext &Ctx = getContext();
+  const MCAsmInfo &MAI = Ctx.getAsmInfo();
+  if (!MAI.doesSupportDataRegionDirectives())
+    return;
+  switch (Kind) {
+  case MCDR_DataRegion:            OS << "\t.data_region"; break;
+  case MCDR_DataRegionJT8:         OS << "\t.data_region jt8"; break;
+  case MCDR_DataRegionJT16:        OS << "\t.data_region jt16"; break;
+  case MCDR_DataRegionJT32:        OS << "\t.data_region jt32"; break;
+  case MCDR_DataRegionEnd:         OS << "\t.end_data_region"; break;
+  }
+  EmitEOL();
+}
+
 void MCAsmStreamer::EmitThumbFunc(MCSymbol *Func) {
   // This needs to emit to a temporary string to get properly quoted
   // MCSymbols when they have spaces in them.
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index 6c4d0e3..6ac9d9d 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -13,6 +13,8 @@
 
 #include "MCELF.h"
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Twine.h"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCCodeEmitter.h"
 #include "llvm/MC/MCContext.h"
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index bc6cf77..970aa8b 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -1,4 +1,3 @@
-//===- lib/MC/MCMachOStreamer.cpp - Mach-O Object Output ------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -33,6 +32,8 @@ class MCMachOStreamer : public MCObjectStreamer {
 private:
   virtual void EmitInstToData(const MCInst &Inst);
 
+  void EmitDataRegion(DataRegionData::KindTy Kind);
+  void EmitDataRegionEnd();
 public:
   MCMachOStreamer(MCContext &Context, MCAsmBackend &MAB,
                   raw_ostream &OS, MCCodeEmitter *Emitter)
@@ -46,6 +47,7 @@ public:
   virtual void EmitEHSymAttributes(const MCSymbol *Symbol,
                                    MCSymbol *EHSymbol);
   virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
+  virtual void EmitDataRegion(MCDataRegionType Kind);
   virtual void EmitThumbFunc(MCSymbol *Func);
   virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
   virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
@@ -138,6 +140,26 @@ void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
   SD.setFlags(SD.getFlags() & ~SF_ReferenceTypeMask);
 }
 
+void MCMachOStreamer::EmitDataRegion(DataRegionData::KindTy Kind) {
+  // Create a temporary label to mark the start of the data region.
+  MCSymbol *Start = getContext().CreateTempSymbol();
+  EmitLabel(Start);
+  // Record the region for the object writer to use.
+  DataRegionData Data = { Kind, Start, NULL };
+  std::vector<DataRegionData> &Regions = getAssembler().getDataRegions();
+  Regions.push_back(Data);
+}
+
+void MCMachOStreamer::EmitDataRegionEnd() {
+  std::vector<DataRegionData> &Regions = getAssembler().getDataRegions();
+  assert(Regions.size() && "Mismatched .end_data_region!");
+  DataRegionData &Data = Regions.back();
+  assert(Data.End == NULL && "Mismatched .end_data_region!");
+  // Create a temporary label to mark the end of the data region.
+  Data.End = getContext().CreateTempSymbol();
+  EmitLabel(Data.End);
+}
+
 void MCMachOStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   // Let the target do whatever target specific stuff it needs to do.
   getAssembler().getBackend().handleAssemblerFlag(Flag);
@@ -153,6 +175,26 @@ void MCMachOStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
   }
 }
 
+void MCMachOStreamer::EmitDataRegion(MCDataRegionType Kind) {
+  switch (Kind) {
+  case MCDR_DataRegion:
+    EmitDataRegion(DataRegionData::Data);
+    return;
+  case MCDR_DataRegionJT8:
+    EmitDataRegion(DataRegionData::JumpTable8);
+    return;
+  case MCDR_DataRegionJT16:
+    EmitDataRegion(DataRegionData::JumpTable16);
+    return;
+  case MCDR_DataRegionJT32:
+    EmitDataRegion(DataRegionData::JumpTable32);
+    return;
+  case MCDR_DataRegionEnd:
+    EmitDataRegionEnd();
+    return;
+  }
+}
+
 void MCMachOStreamer::EmitThumbFunc(MCSymbol *Symbol) {
   // Remember that the function is a thumb function. Fixup and relocation
   // values will need adjusted.
diff --git a/lib/MC/MCParser/DarwinAsmParser.cpp b/lib/MC/MCParser/DarwinAsmParser.cpp
index 6f45068..5662fea 100644
--- a/lib/MC/MCParser/DarwinAsmParser.cpp
+++ b/lib/MC/MCParser/DarwinAsmParser.cpp
@@ -14,6 +14,7 @@
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MCParser/MCAsmLexer.h"
 #include "llvm/MC/MCParser/MCAsmParser.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -56,6 +57,9 @@ public:
     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveTBSS>(".tbss");
     AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveZerofill>(".zerofill");
 
+    AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveDataRegion>(".data_region");
+    AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveDataRegionEnd>(".end_data_region");
+
     // Special section directives.
     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveConst>(".const");
     AddDirectiveHandler<&DarwinAsmParser::ParseSectionDirectiveConstData>(".const_data");
@@ -113,6 +117,8 @@ public:
   bool ParseDirectiveSubsectionsViaSymbols(StringRef, SMLoc);
   bool ParseDirectiveTBSS(StringRef, SMLoc);
   bool ParseDirectiveZerofill(StringRef, SMLoc);
+  bool ParseDirectiveDataRegion(StringRef, SMLoc);
+  bool ParseDirectiveDataRegionEnd(StringRef, SMLoc);
 
   // Named Section Directive
   bool ParseSectionDirectiveConst(StringRef, SMLoc) {
@@ -659,6 +665,42 @@ bool DarwinAsmParser::ParseDirectiveZerofill(StringRef, SMLoc) {
   return false;
 }
 
+/// ParseDirectiveDataRegion
+///  ::= .data_region [ ( jt8 | jt16 | jt32 ) ]
+bool DarwinAsmParser::ParseDirectiveDataRegion(StringRef, SMLoc) {
+  if (getLexer().is(AsmToken::EndOfStatement)) {
+    Lex();
+    getStreamer().EmitDataRegion(MCDR_DataRegion);
+    return false;
+  }
+  StringRef RegionType;
+  SMLoc Loc = getParser().getTok().getLoc();
+  if (getParser().ParseIdentifier(RegionType))
+    return TokError("expected region type after '.data_region' directive");
+  int Kind = StringSwitch<int>(RegionType)
+    .Case("jt8", MCDR_DataRegionJT8)
+    .Case("jt16", MCDR_DataRegionJT16)
+    .Case("jt32", MCDR_DataRegionJT32)
+    .Default(-1);
+  if (Kind == -1)
+    return Error(Loc, "unknown region type in '.data_region' directive");
+  Lex();
+
+  getStreamer().EmitDataRegion((MCDataRegionType)Kind);
+  return false;
+}
+
+/// ParseDirectiveDataRegionEnd
+///  ::= .end_data_region
+bool DarwinAsmParser::ParseDirectiveDataRegionEnd(StringRef, SMLoc) {
+  if (getLexer().isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.end_data_region' directive");
+
+  Lex();
+  getStreamer().EmitDataRegion(MCDR_DataRegionEnd);
+  return false;
+}
+
 namespace llvm {
 
 MCAsmParserExtension *createDarwinAsmParser() {
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index 43e62ff..e363f28 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/lib/MC/MCStreamer.cpp
@@ -20,12 +20,9 @@
 #include <cstdlib>
 using namespace llvm;
 
-MCStreamer::MCStreamer(MCContext &Ctx) : Context(Ctx), EmitEHFrame(true),
-                                         EmitDebugFrame(false),
-                                         CurrentW64UnwindInfo(0),
-                                         LastSymbol(0),
-                                         UniqueCodeBeginSuffix(0),
-                                         UniqueDataBeginSuffix(0) {
+MCStreamer::MCStreamer(MCContext &Ctx)
+  : Context(Ctx), EmitEHFrame(true), EmitDebugFrame(false),
+    CurrentW64UnwindInfo(0), LastSymbol(0) {
   const MCSection *section = NULL;
   SectionStack.push_back(std::make_pair(section, section));
 }
@@ -183,85 +180,6 @@ void MCStreamer::EmitLabel(MCSymbol *Symbol) {
   LastSymbol = Symbol;
 }
 
-void MCStreamer::EmitDataRegion() {
-  if (RegionIndicator == Data) return;
-
-  MCContext &Context = getContext();
-  const MCAsmInfo &MAI = Context.getAsmInfo();
-  if (!MAI.getSupportsDataRegions()) return;
-
-  // Generate a unique symbol name.
-  MCSymbol *NewSym = Context.GetOrCreateSymbol(MAI.getDataBeginLabelName() +
-                                               Twine(UniqueDataBeginSuffix++));
-  EmitLabel(NewSym);
-
-  RegionIndicator = Data;
-}
-
-void MCStreamer::EmitCodeRegion() {
-  if (RegionIndicator == Code) return;
-
-  MCContext &Context = getContext();
-  const MCAsmInfo &MAI = Context.getAsmInfo();
-  if (!MAI.getSupportsDataRegions()) return;
-
-  // Generate a unique symbol name.
-  MCSymbol *NewSym = Context.GetOrCreateSymbol(MAI.getCodeBeginLabelName() +
-                                               Twine(UniqueCodeBeginSuffix++));
-  EmitLabel(NewSym);
-
-  RegionIndicator = Code;
-}
-
-void MCStreamer::EmitJumpTable8Region() {
-  if (RegionIndicator == JumpTable8) return;
-
-  MCContext &Context = getContext();
-  const MCAsmInfo &MAI = Context.getAsmInfo();
-  if (!MAI.getSupportsDataRegions()) return;
-
-  // Generate a unique symbol name.
-  MCSymbol *NewSym =
-    Context.GetOrCreateSymbol(MAI.getJumpTable8BeginLabelName() +
-                              Twine(UniqueDataBeginSuffix++));
-  EmitLabel(NewSym);
-
-  RegionIndicator = JumpTable8;
-}
-
-void MCStreamer::EmitJumpTable16Region() {
-  if (RegionIndicator == JumpTable16) return;
-
-  MCContext &Context = getContext();
-  const MCAsmInfo &MAI = Context.getAsmInfo();
-  if (!MAI.getSupportsDataRegions()) return;
-
-  // Generate a unique symbol name.
-  MCSymbol *NewSym =
-    Context.GetOrCreateSymbol(MAI.getJumpTable16BeginLabelName() +
-                              Twine(UniqueDataBeginSuffix++));
-  EmitLabel(NewSym);
-
-  RegionIndicator = JumpTable16;
-}
-
-
-void MCStreamer::EmitJumpTable32Region() {
-  if (RegionIndicator == JumpTable32) return;
-
-  MCContext &Context = getContext();
-  const MCAsmInfo &MAI = Context.getAsmInfo();
-  if (!MAI.getSupportsDataRegions()) return;
-
-  // Generate a unique symbol name.
-  MCSymbol *NewSym =
-    Context.GetOrCreateSymbol(MAI.getJumpTable32BeginLabelName() +
-                              Twine(UniqueDataBeginSuffix++));
-  EmitLabel(NewSym);
-
-  RegionIndicator = JumpTable32;
-}
-
 void MCStreamer::EmitCompactUnwindEncoding(uint32_t CompactUnwindEncoding) {
   EnsureValidFrame();
   MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
@@ -283,7 +201,6 @@ void MCStreamer::EmitCFIStartProc() {
   EmitCFIStartProcImpl(Frame);
 
   FrameInfos.push_back(Frame);
-  RegionIndicator = Code;
 }
 
 void MCStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
index 8e4066c..5820a22 100644
--- a/lib/MC/MachObjectWriter.cpp
+++ b/lib/MC/MachObjectWriter.cpp
@@ -21,6 +21,7 @@
 #include "llvm/MC/MCMachOSymbolFlags.h"
 #include "llvm/MC/MCValue.h"
 #include "llvm/Object/MachOFormat.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 
 #include <vector>
@@ -351,6 +352,21 @@ void MachObjectWriter::WriteNlist(MachSymbolData &MSD,
     Write32(Address);
 }
 
+void MachObjectWriter::WriteLinkeditLoadCommand(uint32_t Type,
+                                                uint32_t DataOffset,
+                                                uint32_t DataSize) {
+  uint64_t Start = OS.tell();
+  (void) Start;
+
+  Write32(Type);
+  Write32(macho::LinkeditLoadCommandSize);
+  Write32(DataOffset);
+  Write32(DataSize);
+
+  assert(OS.tell() - Start == macho::LinkeditLoadCommandSize);
+}
+
+
 void MachObjectWriter::RecordRelocation(const MCAssembler &Asm,
                                         const MCAsmLayout &Layout,
                                         const MCFragment *Fragment,
@@ -654,6 +670,13 @@ void MachObjectWriter::WriteObject(MCAssembler &Asm,
                          macho::DysymtabLoadCommandSize);
   }
 
+  // Add the data-in-code load command size, if used.
+  unsigned NumDataRegions = Asm.getDataRegions().size();
+  if (NumDataRegions) {
+    ++NumLoadCommands;
+    LoadCommandsSize += macho::LinkeditLoadCommandSize;
+  }
+
   // Compute the total size of the section data, as well as its file size and vm
   // size.
   uint64_t SectionDataStart = (is64Bit() ? macho::Header64Size :
@@ -701,6 +724,15 @@ void MachObjectWriter::WriteObject(MCAssembler &Asm,
     RelocTableEnd += NumRelocs * macho::RelocationInfoSize;
   }
 
+  // Write the data-in-code load command, if used.
+  uint64_t DataInCodeTableEnd = RelocTableEnd + NumDataRegions * 8;
+  if (NumDataRegions) {
+    uint64_t DataRegionsOffset = RelocTableEnd;
+    uint64_t DataRegionsSize = NumDataRegions * 8;
+    WriteLinkeditLoadCommand(macho::LCT_DataInCode, DataRegionsOffset,
+                             DataRegionsSize);
+  }
+
   // Write the symbol table load command, if used.
   if (NumSymbols) {
     unsigned FirstLocalSymbol = 0;
@@ -717,10 +749,10 @@ void MachObjectWriter::WriteObject(MCAssembler &Asm,
 
     // If used, the indirect symbols are written after the section data.
     if (NumIndirectSymbols)
-      IndirectSymbolOffset = RelocTableEnd;
+      IndirectSymbolOffset = DataInCodeTableEnd;
 
     // The symbol table is written after the indirect symbol data.
-    uint64_t SymbolTableOffset = RelocTableEnd + IndirectSymbolSize;
+    uint64_t SymbolTableOffset = DataInCodeTableEnd + IndirectSymbolSize;
 
     // The string table is written after symbol table.
     uint64_t StringTableOffset =
@@ -760,6 +792,23 @@ void MachObjectWriter::WriteObject(MCAssembler &Asm,
     }
   }
 
+  // Write out the data-in-code region payload, if there is one.
+  for (MCAssembler::const_data_region_iterator
+         it = Asm.data_region_begin(), ie = Asm.data_region_end();
+         it != ie; ++it) {
+    const DataRegionData *Data = &(*it);
+    uint64_t Start = getSymbolAddress(&Layout.getAssembler().getSymbolData(*Data->Start), Layout);
+    uint64_t End = getSymbolAddress(&Layout.getAssembler().getSymbolData(*Data->End), Layout);
+    DEBUG(dbgs() << "data in code region-- kind: " << Data->Kind
+                 << "  start: " << Start << "(" << Data->Start->getName() << ")"
+                 << "  end: " << End << "(" << Data->End->getName() << ")"
+                 << "  size: " << End - Start
+                 << "\n");
+    Write32(Start);
+    Write16(End - Start);
+    Write16(Data->Kind);
+  }
+
   // Write the symbol table data, if used.
   if (NumSymbols) {
     // Write the indirect symbol entries.
diff --git a/lib/Object/MachOObject.cpp b/lib/Object/MachOObject.cpp
index b7e5cdc..00dea3f 100644
--- a/lib/Object/MachOObject.cpp
+++ b/lib/Object/MachOObject.cpp
@@ -357,6 +357,19 @@ void MachOObject::ReadSymbol64TableEntry(uint64_t SymbolTableOffset,
   ReadInMemoryStruct(*this, Buffer->getBuffer(), Offset, Res);
 }
 
+template<>
+void SwapStruct(macho::DataInCodeTableEntry &Value) {
+  SwapValue(Value.Offset);
+  SwapValue(Value.Length);
+  SwapValue(Value.Kind);
+}
+void MachOObject::ReadDataInCodeTableEntry(uint64_t TableOffset,
+                                           unsigned Index,
+                       InMemoryStruct<macho::DataInCodeTableEntry> &Res) const {
+  uint64_t Offset = (TableOffset +
+                     Index * sizeof(macho::DataInCodeTableEntry));
+  ReadInMemoryStruct(*this, Buffer->getBuffer(), Offset, Res);
+}
 
 void MachOObject::ReadULEB128s(uint64_t Index,
                                SmallVectorImpl<uint64_t> &Out) const {
diff --git a/lib/Target/ARM/ARMAsmPrinter.cpp b/lib/Target/ARM/ARMAsmPrinter.cpp
index 410790a..e781498 100644
--- a/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -283,9 +283,16 @@ void ARMAsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc) const {
   }
 }
 
-void ARMAsmPrinter::EmitFunctionEntryLabel() {
-  OutStreamer.ForceCodeRegion();
+void ARMAsmPrinter::EmitFunctionBodyEnd() {
+  // Make sure to terminate any constant pools that were at the end
+  // of the function.
+  if (!InConstantPool)
+    return;
+  InConstantPool = false;
+  OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
+}
 
+void ARMAsmPrinter::EmitFunctionEntryLabel() {
   if (AFI->isThumbFunction()) {
     OutStreamer.EmitAssemblerFlag(MCAF_Code16);
     OutStreamer.EmitThumbFunc(CurrentFnSym);
@@ -934,13 +941,13 @@ void ARMAsmPrinter::EmitJumpTable(const MachineInstr *MI) {
   const MachineOperand &MO2 = MI->getOperand(OpNum+1); // Unique Id
   unsigned JTI = MO1.getIndex();
 
-  // Tag the jump table appropriately for precise disassembly.
-  OutStreamer.EmitJumpTable32Region();
-
   // Emit a label for the jump table.
   MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel2(JTI, MO2.getImm());
   OutStreamer.EmitLabel(JTISymbol);
 
+  // Mark the jump table as data-in-code.
+  OutStreamer.EmitDataRegion(MCDR_DataRegionJT32);
+
   // Emit each entry of the table.
   const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
@@ -969,6 +976,8 @@ void ARMAsmPrinter::EmitJumpTable(const MachineInstr *MI) {
                                      OutContext);
     OutStreamer.EmitValue(Expr, 4);
   }
+  // Mark the end of jump table data-in-code region.
+  OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
 }
 
 void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
@@ -978,15 +987,6 @@ void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
   const MachineOperand &MO2 = MI->getOperand(OpNum+1); // Unique Id
   unsigned JTI = MO1.getIndex();
 
-  // Emit a label for the jump table.
-  if (MI->getOpcode() == ARM::t2TBB_JT) {
-    OutStreamer.EmitJumpTable8Region();
-  } else if (MI->getOpcode() == ARM::t2TBH_JT) {
-    OutStreamer.EmitJumpTable16Region();
-  } else {
-    OutStreamer.EmitJumpTable32Region();
-  }
-
   MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel2(JTI, MO2.getImm());
   OutStreamer.EmitLabel(JTISymbol);
 
@@ -995,10 +995,15 @@ void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
   const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
   const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
   unsigned OffsetWidth = 4;
-  if (MI->getOpcode() == ARM::t2TBB_JT)
+  if (MI->getOpcode() == ARM::t2TBB_JT) {
     OffsetWidth = 1;
-  else if (MI->getOpcode() == ARM::t2TBH_JT)
+    // Mark the jump table as data-in-code.
+    OutStreamer.EmitDataRegion(MCDR_DataRegionJT8);
+  } else if (MI->getOpcode() == ARM::t2TBH_JT) {
     OffsetWidth = 2;
+    // Mark the jump table as data-in-code.
+    OutStreamer.EmitDataRegion(MCDR_DataRegionJT16);
+  }
 
   for (unsigned i = 0, e = JTBBs.size(); i != e; ++i) {
     MachineBasicBlock *MBB = JTBBs[i];
@@ -1031,6 +1036,8 @@ void ARMAsmPrinter::EmitJump2Table(const MachineInstr *MI) {
                                    OutContext);
     OutStreamer.EmitValue(Expr, OffsetWidth);
   }
+  // Mark the end of jump table data-in-code region.
+  OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
 }
 
 void ARMAsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
@@ -1208,8 +1215,11 @@ extern cl::opt<bool> EnableARMEHABI;
 #include "ARMGenMCPseudoLowering.inc"
 
 void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
-  if (MI->getOpcode() != ARM::CONSTPOOL_ENTRY)
-    OutStreamer.EmitCodeRegion();
+  // If we just ended a constant pool, mark it as such.
+  if (InConstantPool && MI->getOpcode() != ARM::CONSTPOOL_ENTRY) {
+    OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
+    InConstantPool = false;
+  }
 
   // Emit unwinding stuff for frame-related instructions
   if (EnableARMEHABI && MI->getFlag(MachineInstr::FrameSetup))
@@ -1565,9 +1575,12 @@ void ARMAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     unsigned LabelId = (unsigned)MI->getOperand(0).getImm();
     unsigned CPIdx   = (unsigned)MI->getOperand(1).getIndex();
 
-    // Mark the constant pool entry as data if we're not already in a data
-    // region.
-    OutStreamer.EmitDataRegion();
+    // If this is the first entry of the pool, mark it.
+    if (!InConstantPool) {
+      OutStreamer.EmitDataRegion(MCDR_DataRegion);
+      InConstantPool = true;
+    }
+
     OutStreamer.EmitLabel(GetCPISymbol(LabelId));
 
     const MachineConstantPoolEntry &MCPE = MCP->getConstants()[CPIdx];
diff --git a/lib/Target/ARM/ARMAsmPrinter.h b/lib/Target/ARM/ARMAsmPrinter.h
index af3f75a..3555e8f 100644
--- a/lib/Target/ARM/ARMAsmPrinter.h
+++ b/lib/Target/ARM/ARMAsmPrinter.h
@@ -44,9 +44,12 @@ class LLVM_LIBRARY_VISIBILITY ARMAsmPrinter : public AsmPrinter {
   /// MachineFunction.
   const MachineConstantPool *MCP;
 
+  /// InConstantPool - Maintain state when emitting a sequence of constant
+  /// pool entries so we can properly mark them as data regions.
+  bool InConstantPool;
 public:
   explicit ARMAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
-    : AsmPrinter(TM, Streamer), AFI(NULL), MCP(NULL) {
+    : AsmPrinter(TM, Streamer), AFI(NULL), MCP(NULL), InConstantPool(false) {
       Subtarget = &TM.getSubtarget<ARMSubtarget>();
     }
 
@@ -70,6 +73,7 @@ public:
   bool runOnMachineFunction(MachineFunction &F);
 
   virtual void EmitConstantPool() {} // we emit constant pools customly!
+  virtual void EmitFunctionBodyEnd();
   virtual void EmitFunctionEntryLabel();
   void EmitStartOfAsmFile(Module &M);
   void EmitEndOfAsmFile(Module &M);
diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp b/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
index 4ac7741..d32805e 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
@@ -29,6 +29,7 @@ ARMMCAsmInfoDarwin::ARMMCAsmInfoDarwin() {
   CommentString = "@";
   Code16Directive = ".code\t16";
   Code32Directive = ".code\t32";
+  UseDataRegionDirectives = true;
 
   SupportsDebugInformation = true;
 
diff --git a/lib/Target/X86/X86MCInstLower.cpp b/lib/Target/X86/X86MCInstLower.cpp
index 54bfce1..2f368b6 100644
--- a/lib/Target/X86/X86MCInstLower.cpp
+++ b/lib/Target/X86/X86MCInstLower.cpp
@@ -610,8 +610,6 @@ static void LowerTlsAddr(MCStreamer &OutStreamer,
 }
 
 void X86AsmPrinter::EmitInstruction(const MachineInstr *MI) {
-  OutStreamer.EmitCodeRegion();
-
   X86MCInstLower MCInstLowering(Mang, *MF, *this);
   switch (MI->getOpcode()) {
   case TargetOpcode::DBG_VALUE: