Vendor import of llvm trunk r154661:

http://llvm.org/svn/llvm-project/llvm/trunk@r154661

10 files changed, 680 insertions, 484 deletions

diff --git a/lib/Bitcode/LLVMBuild.txt b/lib/Bitcode/LLVMBuild.txt
new file mode 100644
index 0000000..af9936b
--- /dev/null
+++ b/lib/Bitcode/LLVMBuild.txt
@@ -0,0 +1,24 @@
+;===- ./lib/Bitcode/LLVMBuild.txt ------------------------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[common]
+subdirectories = Reader Writer
+
+[component_0]
+type = Group
+name = Bitcode
+parent = Libraries
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 46565f3..e399040 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -22,11 +22,19 @@
 #include "llvm/AutoUpgrade.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/DataStream.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/OperandTraits.h"
 using namespace llvm;
 
+void BitcodeReader::materializeForwardReferencedFunctions() {
+  while (!BlockAddrFwdRefs.empty()) {
+    Function *F = BlockAddrFwdRefs.begin()->first;
+    F->Materialize();
+  }
+}
+
 void BitcodeReader::FreeState() {
   if (BufferOwned)
     delete Buffer;
@@ -394,7 +402,7 @@ Type *BitcodeReader::getTypeByID(unsigned ID) {
   // The type table size is always specified correctly.
   if (ID >= TypeList.size())
     return 0;
-  
+
   if (Type *Ty = TypeList[ID])
     return Ty;
 
@@ -403,14 +411,6 @@ Type *BitcodeReader::getTypeByID(unsigned ID) {
   return TypeList[ID] = StructType::create(Context);
 }
 
-/// FIXME: Remove in LLVM 3.1, only used by ParseOldTypeTable.
-Type *BitcodeReader::getTypeByIDOrNull(unsigned ID) {
-  if (ID >= TypeList.size())
-    TypeList.resize(ID+1);
-  
-  return TypeList[ID];
-}
-
 
 //===----------------------------------------------------------------------===//
 //  Functions for parsing blocks from the bitcode file
@@ -462,8 +462,8 @@ bool BitcodeReader::ParseAttributeBlock() {
       // If Function attributes are using index 0 then transfer them
       // to index ~0. Index 0 is used for return value attributes but used to be
       // used for function attributes.
-      Attributes RetAttribute = Attribute::None;
-      Attributes FnAttribute = Attribute::None;
+      Attributes RetAttribute;
+      Attributes FnAttribute;
       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
         // FIXME: remove in LLVM 3.0
         // The alignment is stored as a 16-bit raw value from bits 31--16.
@@ -473,23 +473,24 @@ bool BitcodeReader::ParseAttributeBlock() {
         if (Alignment && !isPowerOf2_32(Alignment))
           return Error("Alignment is not a power of two.");
 
-        Attributes ReconstitutedAttr = Record[i+1] & 0xffff;
+        Attributes ReconstitutedAttr(Record[i+1] & 0xffff);
         if (Alignment)
           ReconstitutedAttr |= Attribute::constructAlignmentFromInt(Alignment);
-        ReconstitutedAttr |= (Record[i+1] & (0xffffull << 32)) >> 11;
-        Record[i+1] = ReconstitutedAttr;
+        ReconstitutedAttr |=
+            Attributes((Record[i+1] & (0xffffull << 32)) >> 11);
 
+        Record[i+1] = ReconstitutedAttr.Raw();
         if (Record[i] == 0)
-          RetAttribute = Record[i+1];
+          RetAttribute = ReconstitutedAttr;
         else if (Record[i] == ~0U)
-          FnAttribute = Record[i+1];
+          FnAttribute = ReconstitutedAttr;
       }
 
-      unsigned OldRetAttrs = (Attribute::NoUnwind|Attribute::NoReturn|
+      Attributes OldRetAttrs = (Attribute::NoUnwind|Attribute::NoReturn|
                               Attribute::ReadOnly|Attribute::ReadNone);
 
       if (FnAttribute == Attribute::None && RetAttribute != Attribute::None &&
-          (RetAttribute & OldRetAttrs) != 0) {
+          (RetAttribute & OldRetAttrs)) {
         if (FnAttribute == Attribute::None) { // add a slot so they get added.
           Record.push_back(~0U);
           Record.push_back(0);
@@ -506,8 +507,9 @@ bool BitcodeReader::ParseAttributeBlock() {
         } else if (Record[i] == ~0U) {
           if (FnAttribute != Attribute::None)
             Attrs.push_back(AttributeWithIndex::get(~0U, FnAttribute));
-        } else if (Record[i+1] != Attribute::None)
-          Attrs.push_back(AttributeWithIndex::get(Record[i], Record[i+1]));
+        } else if (Attributes(Record[i+1]) != Attribute::None)
+          Attrs.push_back(AttributeWithIndex::get(Record[i],
+                                                  Attributes(Record[i+1])));
       }
 
       MAttributes.push_back(AttrListPtr::get(Attrs.begin(), Attrs.end()));
@@ -521,7 +523,7 @@ bool BitcodeReader::ParseAttributeBlock() {
 bool BitcodeReader::ParseTypeTable() {
   if (Stream.EnterSubBlock(bitc::TYPE_BLOCK_ID_NEW))
     return Error("Malformed block record");
-  
+
   return ParseTypeTableBody();
 }
 
@@ -533,7 +535,7 @@ bool BitcodeReader::ParseTypeTableBody() {
   unsigned NumRecords = 0;
 
   SmallString<64> TypeName;
-  
+
   // Read all the records for this type table.
   while (1) {
     unsigned Code = Stream.ReadCode();
@@ -573,6 +575,9 @@ bool BitcodeReader::ParseTypeTableBody() {
     case bitc::TYPE_CODE_VOID:      // VOID
       ResultTy = Type::getVoidTy(Context);
       break;
+    case bitc::TYPE_CODE_HALF:     // HALF
+      ResultTy = Type::getHalfTy(Context);
+      break;
     case bitc::TYPE_CODE_FLOAT:     // FLOAT
       ResultTy = Type::getFloatTy(Context);
       break;
@@ -615,12 +620,12 @@ bool BitcodeReader::ParseTypeTableBody() {
       ResultTy = PointerType::get(ResultTy, AddressSpace);
       break;
     }
-    case bitc::TYPE_CODE_FUNCTION: {
+    case bitc::TYPE_CODE_FUNCTION_OLD: {
       // FIXME: attrid is dead, remove it in LLVM 3.0
       // FUNCTION: [vararg, attrid, retty, paramty x N]
       if (Record.size() < 3)
         return Error("Invalid FUNCTION type record");
-      std::vector<Type*> ArgTys;
+      SmallVector<Type*, 8> ArgTys;
       for (unsigned i = 3, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
           ArgTys.push_back(T);
@@ -635,10 +640,29 @@ bool BitcodeReader::ParseTypeTableBody() {
       ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
       break;
     }
+    case bitc::TYPE_CODE_FUNCTION: {
+      // FUNCTION: [vararg, retty, paramty x N]
+      if (Record.size() < 2)
+        return Error("Invalid FUNCTION type record");
+      SmallVector<Type*, 8> ArgTys;
+      for (unsigned i = 2, e = Record.size(); i != e; ++i) {
+        if (Type *T = getTypeByID(Record[i]))
+          ArgTys.push_back(T);
+        else
+          break;
+      }
+      
+      ResultTy = getTypeByID(Record[1]);
+      if (ResultTy == 0 || ArgTys.size() < Record.size()-2)
+        return Error("invalid type in function type");
+
+      ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
+      break;
+    }
     case bitc::TYPE_CODE_STRUCT_ANON: {  // STRUCT: [ispacked, eltty x N]
       if (Record.size() < 1)
         return Error("Invalid STRUCT type record");
-      std::vector<Type*> EltTys;
+      SmallVector<Type*, 8> EltTys;
       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
           EltTys.push_back(T);
@@ -728,247 +752,6 @@ bool BitcodeReader::ParseTypeTableBody() {
   }
 }
 
-// FIXME: Remove in LLVM 3.1
-bool BitcodeReader::ParseOldTypeTable() {
-  if (Stream.EnterSubBlock(bitc::TYPE_BLOCK_ID_OLD))
-    return Error("Malformed block record");
-
-  if (!TypeList.empty())
-    return Error("Multiple TYPE_BLOCKs found!");
-  
-  
-  // While horrible, we have no good ordering of types in the bc file.  Just
-  // iteratively parse types out of the bc file in multiple passes until we get
-  // them all.  Do this by saving a cursor for the start of the type block.
-  BitstreamCursor StartOfTypeBlockCursor(Stream);
-  
-  unsigned NumTypesRead = 0;
-  
-  SmallVector<uint64_t, 64> Record;
-RestartScan:
-  unsigned NextTypeID = 0;
-  bool ReadAnyTypes = false;
-  
-  // Read all the records for this type table.
-  while (1) {
-    unsigned Code = Stream.ReadCode();
-    if (Code == bitc::END_BLOCK) {
-      if (NextTypeID != TypeList.size())
-        return Error("Invalid type forward reference in TYPE_BLOCK_ID_OLD");
-      
-      // If we haven't read all of the types yet, iterate again.
-      if (NumTypesRead != TypeList.size()) {
-        // If we didn't successfully read any types in this pass, then we must
-        // have an unhandled forward reference.
-        if (!ReadAnyTypes)
-          return Error("Obsolete bitcode contains unhandled recursive type");
-        
-        Stream = StartOfTypeBlockCursor;
-        goto RestartScan;
-      }
-      
-      if (Stream.ReadBlockEnd())
-        return Error("Error at end of type table block");
-      return false;
-    }
-    
-    if (Code == bitc::ENTER_SUBBLOCK) {
-      // No known subblocks, always skip them.
-      Stream.ReadSubBlockID();
-      if (Stream.SkipBlock())
-        return Error("Malformed block record");
-      continue;
-    }
-    
-    if (Code == bitc::DEFINE_ABBREV) {
-      Stream.ReadAbbrevRecord();
-      continue;
-    }
-    
-    // Read a record.
-    Record.clear();
-    Type *ResultTy = 0;
-    switch (Stream.ReadRecord(Code, Record)) {
-    default: return Error("unknown type in type table");
-    case bitc::TYPE_CODE_NUMENTRY: // TYPE_CODE_NUMENTRY: [numentries]
-      // TYPE_CODE_NUMENTRY contains a count of the number of types in the
-      // type list.  This allows us to reserve space.
-      if (Record.size() < 1)
-        return Error("Invalid TYPE_CODE_NUMENTRY record");
-      TypeList.resize(Record[0]);
-      continue;
-    case bitc::TYPE_CODE_VOID:      // VOID
-      ResultTy = Type::getVoidTy(Context);
-      break;
-    case bitc::TYPE_CODE_FLOAT:     // FLOAT
-      ResultTy = Type::getFloatTy(Context);
-      break;
-    case bitc::TYPE_CODE_DOUBLE:    // DOUBLE
-      ResultTy = Type::getDoubleTy(Context);
-      break;
-    case bitc::TYPE_CODE_X86_FP80:  // X86_FP80
-      ResultTy = Type::getX86_FP80Ty(Context);
-      break;
-    case bitc::TYPE_CODE_FP128:     // FP128
-      ResultTy = Type::getFP128Ty(Context);
-      break;
-    case bitc::TYPE_CODE_PPC_FP128: // PPC_FP128
-      ResultTy = Type::getPPC_FP128Ty(Context);
-      break;
-    case bitc::TYPE_CODE_LABEL:     // LABEL
-      ResultTy = Type::getLabelTy(Context);
-      break;
-    case bitc::TYPE_CODE_METADATA:  // METADATA
-      ResultTy = Type::getMetadataTy(Context);
-      break;
-    case bitc::TYPE_CODE_X86_MMX:   // X86_MMX
-      ResultTy = Type::getX86_MMXTy(Context);
-      break;
-    case bitc::TYPE_CODE_INTEGER:   // INTEGER: [width]
-      if (Record.size() < 1)
-        return Error("Invalid Integer type record");
-      ResultTy = IntegerType::get(Context, Record[0]);
-      break;
-    case bitc::TYPE_CODE_OPAQUE:    // OPAQUE
-      if (NextTypeID < TypeList.size() && TypeList[NextTypeID] == 0)
-        ResultTy = StructType::create(Context);
-      break;
-    case bitc::TYPE_CODE_STRUCT_OLD: {// STRUCT_OLD
-      if (NextTypeID >= TypeList.size()) break;
-      // If we already read it, don't reprocess.
-      if (TypeList[NextTypeID] &&
-          !cast<StructType>(TypeList[NextTypeID])->isOpaque())
-        break;
-
-      // Set a type.
-      if (TypeList[NextTypeID] == 0)
-        TypeList[NextTypeID] = StructType::create(Context);
-
-      std::vector<Type*> EltTys;
-      for (unsigned i = 1, e = Record.size(); i != e; ++i) {
-        if (Type *Elt = getTypeByIDOrNull(Record[i]))
-          EltTys.push_back(Elt);
-        else
-          break;
-      }
-
-      if (EltTys.size() != Record.size()-1)
-        break;      // Not all elements are ready.
-      
-      cast<StructType>(TypeList[NextTypeID])->setBody(EltTys, Record[0]);
-      ResultTy = TypeList[NextTypeID];
-      TypeList[NextTypeID] = 0;
-      break;
-    }
-    case bitc::TYPE_CODE_POINTER: { // POINTER: [pointee type] or
-      //          [pointee type, address space]
-      if (Record.size() < 1)
-        return Error("Invalid POINTER type record");
-      unsigned AddressSpace = 0;
-      if (Record.size() == 2)
-        AddressSpace = Record[1];
-      if ((ResultTy = getTypeByIDOrNull(Record[0])))
-        ResultTy = PointerType::get(ResultTy, AddressSpace);
-      break;
-    }
-    case bitc::TYPE_CODE_FUNCTION: {
-      // FIXME: attrid is dead, remove it in LLVM 3.0
-      // FUNCTION: [vararg, attrid, retty, paramty x N]
-      if (Record.size() < 3)
-        return Error("Invalid FUNCTION type record");
-      std::vector<Type*> ArgTys;
-      for (unsigned i = 3, e = Record.size(); i != e; ++i) {
-        if (Type *Elt = getTypeByIDOrNull(Record[i]))
-          ArgTys.push_back(Elt);
-        else
-          break;
-      }
-      if (ArgTys.size()+3 != Record.size())
-        break;  // Something was null.
-      if ((ResultTy = getTypeByIDOrNull(Record[2])))
-        ResultTy = FunctionType::get(ResultTy, ArgTys, Record[0]);
-      break;
-    }
-    case bitc::TYPE_CODE_ARRAY:     // ARRAY: [numelts, eltty]
-      if (Record.size() < 2)
-        return Error("Invalid ARRAY type record");
-      if ((ResultTy = getTypeByIDOrNull(Record[1])))
-        ResultTy = ArrayType::get(ResultTy, Record[0]);
-      break;
-    case bitc::TYPE_CODE_VECTOR:    // VECTOR: [numelts, eltty]
-      if (Record.size() < 2)
-        return Error("Invalid VECTOR type record");
-      if ((ResultTy = getTypeByIDOrNull(Record[1])))
-        ResultTy = VectorType::get(ResultTy, Record[0]);
-      break;
-    }
-    
-    if (NextTypeID >= TypeList.size())
-      return Error("invalid TYPE table");
-    
-    if (ResultTy && TypeList[NextTypeID] == 0) {
-      ++NumTypesRead;
-      ReadAnyTypes = true;
-      
-      TypeList[NextTypeID] = ResultTy;
-    }
-    
-    ++NextTypeID;
-  }
-}
-
-
-bool BitcodeReader::ParseOldTypeSymbolTable() {
-  if (Stream.EnterSubBlock(bitc::TYPE_SYMTAB_BLOCK_ID_OLD))
-    return Error("Malformed block record");
-
-  SmallVector<uint64_t, 64> Record;
-
-  // Read all the records for this type table.
-  std::string TypeName;
-  while (1) {
-    unsigned Code = Stream.ReadCode();
-    if (Code == bitc::END_BLOCK) {
-      if (Stream.ReadBlockEnd())
-        return Error("Error at end of type symbol table block");
-      return false;
-    }
-
-    if (Code == bitc::ENTER_SUBBLOCK) {
-      // No known subblocks, always skip them.
-      Stream.ReadSubBlockID();
-      if (Stream.SkipBlock())
-        return Error("Malformed block record");
-      continue;
-    }
-
-    if (Code == bitc::DEFINE_ABBREV) {
-      Stream.ReadAbbrevRecord();
-      continue;
-    }
-
-    // Read a record.
-    Record.clear();
-    switch (Stream.ReadRecord(Code, Record)) {
-    default:  // Default behavior: unknown type.
-      break;
-    case bitc::TST_CODE_ENTRY:    // TST_ENTRY: [typeid, namechar x N]
-      if (ConvertToString(Record, 1, TypeName))
-        return Error("Invalid TST_ENTRY record");
-      unsigned TypeID = Record[0];
-      if (TypeID >= TypeList.size())
-        return Error("Invalid Type ID in TST_ENTRY record");
-
-      // Only apply the type name to a struct type with no name.
-      if (StructType *STy = dyn_cast<StructType>(TypeList[TypeID]))
-        if (!STy->isLiteral() && !STy->hasName())
-          STy->setName(TypeName);
-      TypeName.clear();
-      break;
-    }
-  }
-}
-
 bool BitcodeReader::ParseValueSymbolTable() {
   if (Stream.EnterSubBlock(bitc::VALUE_SYMTAB_BLOCK_ID))
     return Error("Malformed block record");
@@ -1262,7 +1045,9 @@ bool BitcodeReader::ParseConstants() {
     case bitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
       if (Record.empty())
         return Error("Invalid FLOAT record");
-      if (CurTy->isFloatTy())
+      if (CurTy->isHalfTy())
+        V = ConstantFP::get(Context, APFloat(APInt(16, (uint16_t)Record[0])));
+      else if (CurTy->isFloatTy())
         V = ConstantFP::get(Context, APFloat(APInt(32, (uint32_t)Record[0])));
       else if (CurTy->isDoubleTy())
         V = ConstantFP::get(Context, APFloat(APInt(64, Record[0])));
@@ -1286,7 +1071,7 @@ bool BitcodeReader::ParseConstants() {
         return Error("Invalid CST_AGGREGATE record");
 
       unsigned Size = Record.size();
-      std::vector<Constant*> Elts;
+      SmallVector<Constant*, 16> Elts;
 
       if (StructType *STy = dyn_cast<StructType>(CurTy)) {
         for (unsigned i = 0; i != Size; ++i)
@@ -1308,35 +1093,78 @@ bool BitcodeReader::ParseConstants() {
       }
       break;
     }
-    case bitc::CST_CODE_STRING: { // STRING: [values]
+    case bitc::CST_CODE_STRING:    // STRING: [values]
+    case bitc::CST_CODE_CSTRING: { // CSTRING: [values]
       if (Record.empty())
-        return Error("Invalid CST_AGGREGATE record");
-
-      ArrayType *ATy = cast<ArrayType>(CurTy);
-      Type *EltTy = ATy->getElementType();
+        return Error("Invalid CST_STRING record");
 
       unsigned Size = Record.size();
-      std::vector<Constant*> Elts;
+      SmallString<16> Elts;
       for (unsigned i = 0; i != Size; ++i)
-        Elts.push_back(ConstantInt::get(EltTy, Record[i]));
-      V = ConstantArray::get(ATy, Elts);
+        Elts.push_back(Record[i]);
+      V = ConstantDataArray::getString(Context, Elts,
+                                       BitCode == bitc::CST_CODE_CSTRING);
       break;
     }
-    case bitc::CST_CODE_CSTRING: { // CSTRING: [values]
+    case bitc::CST_CODE_DATA: {// DATA: [n x value]
       if (Record.empty())
-        return Error("Invalid CST_AGGREGATE record");
-
-      ArrayType *ATy = cast<ArrayType>(CurTy);
-      Type *EltTy = ATy->getElementType();
-
+        return Error("Invalid CST_DATA record");
+      
+      Type *EltTy = cast<SequentialType>(CurTy)->getElementType();
       unsigned Size = Record.size();
-      std::vector<Constant*> Elts;
-      for (unsigned i = 0; i != Size; ++i)
-        Elts.push_back(ConstantInt::get(EltTy, Record[i]));
-      Elts.push_back(Constant::getNullValue(EltTy));
-      V = ConstantArray::get(ATy, Elts);
+      
+      if (EltTy->isIntegerTy(8)) {
+        SmallVector<uint8_t, 16> Elts(Record.begin(), Record.end());
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isIntegerTy(16)) {
+        SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isIntegerTy(32)) {
+        SmallVector<uint32_t, 16> Elts(Record.begin(), Record.end());
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isIntegerTy(64)) {
+        SmallVector<uint64_t, 16> Elts(Record.begin(), Record.end());
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isFloatTy()) {
+        SmallVector<float, 16> Elts;
+        for (unsigned i = 0; i != Size; ++i) {
+          union { uint32_t I; float F; };
+          I = Record[i];
+          Elts.push_back(F);
+        }
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isDoubleTy()) {
+        SmallVector<double, 16> Elts;
+        for (unsigned i = 0; i != Size; ++i) {
+          union { uint64_t I; double F; };
+          I = Record[i];
+          Elts.push_back(F);
+        }
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::get(Context, Elts);
+        else
+          V = ConstantDataArray::get(Context, Elts);
+      } else {
+        return Error("Unknown element type in CE_DATA");
+      }
       break;
     }
+
     case bitc::CST_CODE_CE_BINOP: {  // CE_BINOP: [opcode, opval, opval]
       if (Record.size() < 3) return Error("Invalid CE_BINOP record");
       int Opc = GetDecodedBinaryOpcode(Record[0], CurTy);
@@ -1517,6 +1345,50 @@ bool BitcodeReader::ParseConstants() {
   return false;
 }
 
+bool BitcodeReader::ParseUseLists() {
+  if (Stream.EnterSubBlock(bitc::USELIST_BLOCK_ID))
+    return Error("Malformed block record");
+
+  SmallVector<uint64_t, 64> Record;
+  
+  // Read all the records.
+  while (1) {
+    unsigned Code = Stream.ReadCode();
+    if (Code == bitc::END_BLOCK) {
+      if (Stream.ReadBlockEnd())
+        return Error("Error at end of use-list table block");
+      return false;
+    }
+    
+    if (Code == bitc::ENTER_SUBBLOCK) {
+      // No known subblocks, always skip them.
+      Stream.ReadSubBlockID();
+      if (Stream.SkipBlock())
+        return Error("Malformed block record");
+      continue;
+    }
+    
+    if (Code == bitc::DEFINE_ABBREV) {
+      Stream.ReadAbbrevRecord();
+      continue;
+    }
+    
+    // Read a use list record.
+    Record.clear();
+    switch (Stream.ReadRecord(Code, Record)) {
+    default:  // Default behavior: unknown type.
+      break;
+    case bitc::USELIST_CODE_ENTRY: { // USELIST_CODE_ENTRY: TBD.
+      unsigned RecordLength = Record.size();
+      if (RecordLength < 1)
+        return Error ("Invalid UseList reader!");
+      UseListRecords.push_back(Record);
+      break;
+    }
+    }
+  }
+}
+
 /// RememberAndSkipFunctionBody - When we see the block for a function body,
 /// remember where it is and then skip it.  This lets us lazily deserialize the
 /// functions.
@@ -1538,8 +1410,36 @@ bool BitcodeReader::RememberAndSkipFunctionBody() {
   return false;
 }
 
-bool BitcodeReader::ParseModule() {
-  if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
+bool BitcodeReader::GlobalCleanup() {
+  // Patch the initializers for globals and aliases up.
+  ResolveGlobalAndAliasInits();
+  if (!GlobalInits.empty() || !AliasInits.empty())
+    return Error("Malformed global initializer set");
+
+  // Look for intrinsic functions which need to be upgraded at some point
+  for (Module::iterator FI = TheModule->begin(), FE = TheModule->end();
+       FI != FE; ++FI) {
+    Function *NewFn;
+    if (UpgradeIntrinsicFunction(FI, NewFn))
+      UpgradedIntrinsics.push_back(std::make_pair(FI, NewFn));
+  }
+
+  // Look for global variables which need to be renamed.
+  for (Module::global_iterator
+         GI = TheModule->global_begin(), GE = TheModule->global_end();
+       GI != GE; ++GI)
+    UpgradeGlobalVariable(GI);
+  // Force deallocation of memory for these vectors to favor the client that
+  // want lazy deserialization.
+  std::vector<std::pair<GlobalVariable*, unsigned> >().swap(GlobalInits);
+  std::vector<std::pair<GlobalAlias*, unsigned> >().swap(AliasInits);
+  return false;
+}
+
+bool BitcodeReader::ParseModule(bool Resume) {
+  if (Resume)
+    Stream.JumpToBit(NextUnreadBit);
+  else if (Stream.EnterSubBlock(bitc::MODULE_BLOCK_ID))
     return Error("Malformed block record");
 
   SmallVector<uint64_t, 64> Record;
@@ -1553,33 +1453,7 @@ bool BitcodeReader::ParseModule() {
       if (Stream.ReadBlockEnd())
         return Error("Error at end of module block");
 
-      // Patch the initializers for globals and aliases up.
-      ResolveGlobalAndAliasInits();
-      if (!GlobalInits.empty() || !AliasInits.empty())
-        return Error("Malformed global initializer set");
-      if (!FunctionsWithBodies.empty())
-        return Error("Too few function bodies found");
-
-      // Look for intrinsic functions which need to be upgraded at some point
-      for (Module::iterator FI = TheModule->begin(), FE = TheModule->end();
-           FI != FE; ++FI) {
-        Function* NewFn;
-        if (UpgradeIntrinsicFunction(FI, NewFn))
-          UpgradedIntrinsics.push_back(std::make_pair(FI, NewFn));
-      }
-
-      // Look for global variables which need to be renamed.
-      for (Module::global_iterator
-             GI = TheModule->global_begin(), GE = TheModule->global_end();
-           GI != GE; ++GI)
-        UpgradeGlobalVariable(GI);
-
-      // Force deallocation of memory for these vectors to favor the client that
-      // want lazy deserialization.
-      std::vector<std::pair<GlobalVariable*, unsigned> >().swap(GlobalInits);
-      std::vector<std::pair<GlobalAlias*, unsigned> >().swap(AliasInits);
-      std::vector<Function*>().swap(FunctionsWithBodies);
-      return false;
+      return GlobalCleanup();
     }
 
     if (Code == bitc::ENTER_SUBBLOCK) {
@@ -1600,17 +1474,10 @@ bool BitcodeReader::ParseModule() {
         if (ParseTypeTable())
           return true;
         break;
-      case bitc::TYPE_BLOCK_ID_OLD:
-        if (ParseOldTypeTable())
-          return true;
-        break;
-      case bitc::TYPE_SYMTAB_BLOCK_ID_OLD:
-        if (ParseOldTypeSymbolTable())
-          return true;
-        break;
       case bitc::VALUE_SYMTAB_BLOCK_ID:
         if (ParseValueSymbolTable())
           return true;
+        SeenValueSymbolTable = true;
         break;
       case bitc::CONSTANTS_BLOCK_ID:
         if (ParseConstants() || ResolveGlobalAndAliasInits())
@@ -1623,13 +1490,29 @@ bool BitcodeReader::ParseModule() {
       case bitc::FUNCTION_BLOCK_ID:
         // If this is the first function body we've seen, reverse the
         // FunctionsWithBodies list.
-        if (!HasReversedFunctionsWithBodies) {
+        if (!SeenFirstFunctionBody) {
           std::reverse(FunctionsWithBodies.begin(), FunctionsWithBodies.end());
-          HasReversedFunctionsWithBodies = true;
+          if (GlobalCleanup())
+            return true;
+          SeenFirstFunctionBody = true;
         }
 
         if (RememberAndSkipFunctionBody())
           return true;
+        // For streaming bitcode, suspend parsing when we reach the function
+        // bodies. Subsequent materialization calls will resume it when
+        // necessary. For streaming, the function bodies must be at the end of
+        // the bitcode. If the bitcode file is old, the symbol table will be
+        // at the end instead and will not have been seen yet. In this case,
+        // just finish the parse now.
+        if (LazyStreamer && SeenValueSymbolTable) {
+          NextUnreadBit = Stream.GetCurrentBitNo();
+          return false;
+        }
+        break;
+      case bitc::USELIST_BLOCK_ID:
+        if (ParseUseLists())
+          return true;
         break;
       }
       continue;
@@ -1784,8 +1667,10 @@ bool BitcodeReader::ParseModule() {
 
       // If this is a function with a body, remember the prototype we are
       // creating now, so that we can match up the body with them later.
-      if (!isProto)
+      if (!isProto) {
         FunctionsWithBodies.push_back(Func);
+        if (LazyStreamer) DeferredFunctionInfo[Func] = 0;
+      }
       break;
     }
     // ALIAS: [alias type, aliasee val#, linkage]
@@ -1824,24 +1709,7 @@ bool BitcodeReader::ParseModule() {
 bool BitcodeReader::ParseBitcodeInto(Module *M) {
   TheModule = 0;
 
-  unsigned char *BufPtr = (unsigned char *)Buffer->getBufferStart();
-  unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
-
-  if (Buffer->getBufferSize() & 3) {
-    if (!isRawBitcode(BufPtr, BufEnd) && !isBitcodeWrapper(BufPtr, BufEnd))
-      return Error("Invalid bitcode signature");
-    else
-      return Error("Bitcode stream should be a multiple of 4 bytes in length");
-  }
-
-  // If we have a wrapper header, parse it and ignore the non-bc file contents.
-  // The magic number is 0x0B17C0DE stored in little endian.
-  if (isBitcodeWrapper(BufPtr, BufEnd))
-    if (SkipBitcodeWrapperHeader(BufPtr, BufEnd))
-      return Error("Invalid bitcode wrapper header");
-
-  StreamFile.init(BufPtr, BufEnd);
-  Stream.init(StreamFile);
+  if (InitStream()) return true;
 
   // Sniff for the signature.
   if (Stream.Read(8) != 'B' ||
@@ -1883,8 +1751,9 @@ bool BitcodeReader::ParseBitcodeInto(Module *M) {
       if (TheModule)
         return Error("Multiple MODULE_BLOCKs in same stream");
       TheModule = M;
-      if (ParseModule())
+      if (ParseModule(false))
         return true;
+      if (LazyStreamer) return false;
       break;
     default:
       if (Stream.SkipBlock())
@@ -1952,20 +1821,7 @@ bool BitcodeReader::ParseModuleTriple(std::string &Triple) {
 }
 
 bool BitcodeReader::ParseTriple(std::string &Triple) {
-  if (Buffer->getBufferSize() & 3)
-    return Error("Bitcode stream should be a multiple of 4 bytes in length");
-
-  unsigned char *BufPtr = (unsigned char *)Buffer->getBufferStart();
-  unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
-
-  // If we have a wrapper header, parse it and ignore the non-bc file contents.
-  // The magic number is 0x0B17C0DE stored in little endian.
-  if (isBitcodeWrapper(BufPtr, BufEnd))
-    if (SkipBitcodeWrapperHeader(BufPtr, BufEnd))
-      return Error("Invalid bitcode wrapper header");
-
-  StreamFile.init(BufPtr, BufEnd);
-  Stream.init(StreamFile);
+  if (InitStream()) return true;
 
   // Sniff for the signature.
   if (Stream.Read(8) != 'B' ||
@@ -2517,10 +2373,6 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
       InstructionList.push_back(I);
       break;
     }
-    case bitc::FUNC_CODE_INST_UNWIND: // UNWIND
-      I = new UnwindInst(Context);
-      InstructionList.push_back(I);
-      break;
     case bitc::FUNC_CODE_INST_UNREACHABLE: // UNREACHABLE
       I = new UnreachableInst(Context);
       InstructionList.push_back(I);
@@ -2845,6 +2697,19 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
   return false;
 }
 
+/// FindFunctionInStream - Find the function body in the bitcode stream
+bool BitcodeReader::FindFunctionInStream(Function *F,
+       DenseMap<Function*, uint64_t>::iterator DeferredFunctionInfoIterator) {
+  while (DeferredFunctionInfoIterator->second == 0) {
+    if (Stream.AtEndOfStream())
+      return Error("Could not find Function in stream");
+    // ParseModule will parse the next body in the stream and set its
+    // position in the DeferredFunctionInfo map.
+    if (ParseModule(true)) return true;
+  }
+  return false;
+}
+
 //===----------------------------------------------------------------------===//
 // GVMaterializer implementation
 //===----------------------------------------------------------------------===//
@@ -2865,6 +2730,10 @@ bool BitcodeReader::Materialize(GlobalValue *GV, std::string *ErrInfo) {
 
   DenseMap<Function*, uint64_t>::iterator DFII = DeferredFunctionInfo.find(F);
   assert(DFII != DeferredFunctionInfo.end() && "Deferred function not found!");
+  // If its position is recorded as 0, its body is somewhere in the stream
+  // but we haven't seen it yet.
+  if (DFII->second == 0)
+    if (LazyStreamer && FindFunctionInStream(F, DFII)) return true;
 
   // Move the bit stream to the saved position of the deferred function body.
   Stream.JumpToBit(DFII->second);
@@ -2920,6 +2789,12 @@ bool BitcodeReader::MaterializeModule(Module *M, std::string *ErrInfo) {
         Materialize(F, ErrInfo))
       return true;
 
+  // At this point, if there are any function bodies, the current bit is
+  // pointing to the END_BLOCK record after them. Now make sure the rest
+  // of the bits in the module have been read.
+  if (NextUnreadBit)
+    ParseModule(true);
+
   // Upgrade any intrinsic calls that slipped through (should not happen!) and
   // delete the old functions to clean up. We can't do this unless the entire
   // module is materialized because there could always be another function body
@@ -2939,15 +2814,60 @@ bool BitcodeReader::MaterializeModule(Module *M, std::string *ErrInfo) {
   }
   std::vector<std::pair<Function*, Function*> >().swap(UpgradedIntrinsics);
 
-  // Upgrade to new EH scheme. N.B. This will go away in 3.1.
-  UpgradeExceptionHandling(M);
+  return false;
+}
+
+bool BitcodeReader::InitStream() {
+  if (LazyStreamer) return InitLazyStream();
+  return InitStreamFromBuffer();
+}
+
+bool BitcodeReader::InitStreamFromBuffer() {
+  const unsigned char *BufPtr = (unsigned char *)Buffer->getBufferStart();
+  const unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
+
+  if (Buffer->getBufferSize() & 3) {
+    if (!isRawBitcode(BufPtr, BufEnd) && !isBitcodeWrapper(BufPtr, BufEnd))
+      return Error("Invalid bitcode signature");
+    else
+      return Error("Bitcode stream should be a multiple of 4 bytes in length");
+  }
+
+  // If we have a wrapper header, parse it and ignore the non-bc file contents.
+  // The magic number is 0x0B17C0DE stored in little endian.
+  if (isBitcodeWrapper(BufPtr, BufEnd))
+    if (SkipBitcodeWrapperHeader(BufPtr, BufEnd, true))
+      return Error("Invalid bitcode wrapper header");
 
-  // Check debug info intrinsics.
-  CheckDebugInfoIntrinsics(TheModule);
+  StreamFile.reset(new BitstreamReader(BufPtr, BufEnd));
+  Stream.init(*StreamFile);
 
   return false;
 }
 
+bool BitcodeReader::InitLazyStream() {
+  // Check and strip off the bitcode wrapper; BitstreamReader expects never to
+  // see it.
+  StreamingMemoryObject *Bytes = new StreamingMemoryObject(LazyStreamer);
+  StreamFile.reset(new BitstreamReader(Bytes));
+  Stream.init(*StreamFile);
+
+  unsigned char buf[16];
+  if (Bytes->readBytes(0, 16, buf, NULL) == -1)
+    return Error("Bitcode stream must be at least 16 bytes in length");
+
+  if (!isBitcode(buf, buf + 16))
+    return Error("Invalid bitcode signature");
+
+  if (isBitcodeWrapper(buf, buf + 4)) {
+    const unsigned char *bitcodeStart = buf;
+    const unsigned char *bitcodeEnd = buf + 16;
+    SkipBitcodeWrapperHeader(bitcodeStart, bitcodeEnd, false);
+    Bytes->dropLeadingBytes(bitcodeStart - buf);
+    Bytes->setKnownObjectSize(bitcodeEnd - bitcodeStart);
+  }
+  return false;
+}
 
 //===----------------------------------------------------------------------===//
 // External interface
@@ -2970,6 +2890,27 @@ Module *llvm::getLazyBitcodeModule(MemoryBuffer *Buffer,
   }
   // Have the BitcodeReader dtor delete 'Buffer'.
   R->setBufferOwned(true);
+
+  R->materializeForwardReferencedFunctions();
+
+  return M;
+}
+
+
+Module *llvm::getStreamedBitcodeModule(const std::string &name,
+                                       DataStreamer *streamer,
+                                       LLVMContext &Context,
+                                       std::string *ErrMsg) {
+  Module *M = new Module(name, Context);
+  BitcodeReader *R = new BitcodeReader(streamer, Context);
+  M->setMaterializer(R);
+  if (R->ParseBitcodeInto(M)) {
+    if (ErrMsg)
+      *ErrMsg = R->getErrorString();
+    delete M;  // Also deletes R.
+    return 0;
+  }
+  R->setBufferOwned(false); // no buffer to delete
   return M;
 }
 
@@ -2990,6 +2931,9 @@ Module *llvm::ParseBitcodeFile(MemoryBuffer *Buffer, LLVMContext& Context,
     return 0;
   }
 
+  // TODO: Restore the use-lists to the in-memory state when the bitcode was
+  // written.  We must defer until the Module has been fully materialized.
+
   return M;
 }
 
diff --git a/lib/Bitcode/Reader/BitcodeReader.h b/lib/Bitcode/Reader/BitcodeReader.h
index 6e6118c..e7c4e94 100644
--- a/lib/Bitcode/Reader/BitcodeReader.h
+++ b/lib/Bitcode/Reader/BitcodeReader.h
@@ -126,8 +126,11 @@ class BitcodeReader : public GVMaterializer {
   Module *TheModule;
   MemoryBuffer *Buffer;
   bool BufferOwned;
-  BitstreamReader StreamFile;
+  OwningPtr<BitstreamReader> StreamFile;
   BitstreamCursor Stream;
+  DataStreamer *LazyStreamer;
+  uint64_t NextUnreadBit;
+  bool SeenValueSymbolTable;
   
   const char *ErrorString;
   
@@ -135,6 +138,7 @@ class BitcodeReader : public GVMaterializer {
   BitcodeReaderValueList ValueList;
   BitcodeReaderMDValueList MDValueList;
   SmallVector<Instruction *, 64> InstructionList;
+  SmallVector<SmallVector<uint64_t, 64>, 64> UseListRecords;
 
   std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInits;
   std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
@@ -160,9 +164,10 @@ class BitcodeReader : public GVMaterializer {
   // Map the bitcode's custom MDKind ID to the Module's MDKind ID.
   DenseMap<unsigned, unsigned> MDKindMap;
   
-  // After the module header has been read, the FunctionsWithBodies list is 
-  // reversed.  This keeps track of whether we've done this yet.
-  bool HasReversedFunctionsWithBodies;
+  // Several operations happen after the module header has been read, but
+  // before function bodies are processed. This keeps track of whether
+  // we've done this yet.
+  bool SeenFirstFunctionBody;
   
   /// DeferredFunctionInfo - When function bodies are initially scanned, this
   /// map contains info about where to find deferred function body in the
@@ -177,13 +182,22 @@ class BitcodeReader : public GVMaterializer {
 public:
   explicit BitcodeReader(MemoryBuffer *buffer, LLVMContext &C)
     : Context(C), TheModule(0), Buffer(buffer), BufferOwned(false),
-      ErrorString(0), ValueList(C), MDValueList(C) {
-    HasReversedFunctionsWithBodies = false;
+      LazyStreamer(0), NextUnreadBit(0), SeenValueSymbolTable(false),
+      ErrorString(0), ValueList(C), MDValueList(C),
+      SeenFirstFunctionBody(false) {
+  }
+  explicit BitcodeReader(DataStreamer *streamer, LLVMContext &C)
+    : Context(C), TheModule(0), Buffer(0), BufferOwned(false),
+      LazyStreamer(streamer), NextUnreadBit(0), SeenValueSymbolTable(false),
+      ErrorString(0), ValueList(C), MDValueList(C),
+      SeenFirstFunctionBody(false) {
   }
   ~BitcodeReader() {
     FreeState();
   }
-  
+
+  void materializeForwardReferencedFunctions();
+
   void FreeState();
   
   /// setBufferOwned - If this is true, the reader will destroy the MemoryBuffer
@@ -211,7 +225,6 @@ public:
   bool ParseTriple(std::string &Triple);
 private:
   Type *getTypeByID(unsigned ID);
-  Type *getTypeByIDOrNull(unsigned ID);
   Value *getFnValueByID(unsigned ID, Type *Ty) {
     if (Ty && Ty->isMetadataTy())
       return MDValueList.getValueFwdRef(ID);
@@ -256,21 +269,26 @@ private:
   }
 
   
-  bool ParseModule();
+  bool ParseModule(bool Resume);
   bool ParseAttributeBlock();
   bool ParseTypeTable();
-  bool ParseOldTypeTable();         // FIXME: Remove in LLVM 3.1
   bool ParseTypeTableBody();
 
-  bool ParseOldTypeSymbolTable();   // FIXME: Remove in LLVM 3.1
   bool ParseValueSymbolTable();
   bool ParseConstants();
   bool RememberAndSkipFunctionBody();
   bool ParseFunctionBody(Function *F);
+  bool GlobalCleanup();
   bool ResolveGlobalAndAliasInits();
   bool ParseMetadata();
   bool ParseMetadataAttachment();
   bool ParseModuleTriple(std::string &Triple);
+  bool ParseUseLists();
+  bool InitStream();
+  bool InitStreamFromBuffer();
+  bool InitLazyStream();
+  bool FindFunctionInStream(Function *F,
+         DenseMap<Function*, uint64_t>::iterator DeferredFunctionInfoIterator);
 };
   
 } // End llvm namespace
diff --git a/lib/Bitcode/Reader/CMakeLists.txt b/lib/Bitcode/Reader/CMakeLists.txt
index 37bebc4..693d431 100644
--- a/lib/Bitcode/Reader/CMakeLists.txt
+++ b/lib/Bitcode/Reader/CMakeLists.txt
@@ -2,8 +2,3 @@ add_llvm_library(LLVMBitReader
   BitReader.cpp
   BitcodeReader.cpp
   )
-
-add_llvm_library_dependencies(LLVMBitReader
-  LLVMCore
-  LLVMSupport
-  )
diff --git a/lib/Bitcode/Reader/LLVMBuild.txt b/lib/Bitcode/Reader/LLVMBuild.txt
new file mode 100644
index 0000000..c85a87b
--- /dev/null
+++ b/lib/Bitcode/Reader/LLVMBuild.txt
@@ -0,0 +1,22 @@
+;===- ./lib/Bitcode/Reader/LLVMBuild.txt -----------------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = BitReader
+parent = Bitcode
+required_libraries = Core Support
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 5b3d969..b25d2e9 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Operator.h"
 #include "llvm/ValueSymbolTable.h"
 #include "llvm/ADT/Triple.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
@@ -31,6 +32,12 @@
 #include <map>
 using namespace llvm;
 
+static cl::opt<bool>
+EnablePreserveUseListOrdering("enable-bc-uselist-preserve",
+                              cl::desc("Turn on experimental support for "
+                                       "use-list order preservation."),
+                              cl::init(false), cl::Hidden);
+
 /// These are manifest constants used by the bitcode writer. They do not need to
 /// be kept in sync with the reader, but need to be consistent within this file.
 enum {
@@ -119,7 +126,6 @@ static unsigned GetEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
 
 static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
   switch (Ordering) {
-  default: llvm_unreachable("Unknown atomic ordering");
   case NotAtomic: return bitc::ORDERING_NOTATOMIC;
   case Unordered: return bitc::ORDERING_UNORDERED;
   case Monotonic: return bitc::ORDERING_MONOTONIC;
@@ -128,14 +134,15 @@ static unsigned GetEncodedOrdering(AtomicOrdering Ordering) {
   case AcquireRelease: return bitc::ORDERING_ACQREL;
   case SequentiallyConsistent: return bitc::ORDERING_SEQCST;
   }
+  llvm_unreachable("Invalid ordering");
 }
 
 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
   switch (SynchScope) {
-  default: llvm_unreachable("Unknown synchronization scope");
   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
   }
+  llvm_unreachable("Invalid synch scope");
 }
 
 static void WriteStringRecord(unsigned Code, StringRef Str,
@@ -172,10 +179,11 @@ static void WriteAttributeTable(const ValueEnumerator &VE,
       // Store the alignment in the bitcode as a 16-bit raw value instead of a
       // 5-bit log2 encoded value. Shift the bits above the alignment up by
       // 11 bits.
-      uint64_t FauxAttr = PAWI.Attrs & 0xffff;
+      uint64_t FauxAttr = PAWI.Attrs.Raw() & 0xffff;
       if (PAWI.Attrs & Attribute::Alignment)
-        FauxAttr |= (1ull<<16)<<(((PAWI.Attrs & Attribute::Alignment)-1) >> 16);
-      FauxAttr |= (PAWI.Attrs & (0x3FFull << 21)) << 11;
+        FauxAttr |= (1ull<<16)<<
+            (((PAWI.Attrs & Attribute::Alignment).Raw()-1) >> 16);
+      FauxAttr |= (PAWI.Attrs.Raw() & (0x3FFull << 21)) << 11;
 
       Record.push_back(FauxAttr);
     }
@@ -194,11 +202,12 @@ static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
   SmallVector<uint64_t, 64> TypeVals;
 
+  uint64_t NumBits = Log2_32_Ceil(VE.getTypes().size()+1);
+
   // Abbrev for TYPE_CODE_POINTER.
   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
-                            Log2_32_Ceil(VE.getTypes().size()+1)));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
 
@@ -206,10 +215,9 @@ static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
   Abbv = new BitCodeAbbrev();
   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
-  Abbv->Add(BitCodeAbbrevOp(0));  // FIXME: DEAD value, remove in LLVM 3.0
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
-                            Log2_32_Ceil(VE.getTypes().size()+1)));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
+
   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
 
   // Abbrev for TYPE_CODE_STRUCT_ANON.
@@ -217,8 +225,8 @@ static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
-                            Log2_32_Ceil(VE.getTypes().size()+1)));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
+
   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
 
   // Abbrev for TYPE_CODE_STRUCT_NAME.
@@ -233,16 +241,16 @@ static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
-                            Log2_32_Ceil(VE.getTypes().size()+1)));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
+
   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
   
   // Abbrev for TYPE_CODE_ARRAY.
   Abbv = new BitCodeAbbrev();
   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
-                            Log2_32_Ceil(VE.getTypes().size()+1)));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
+
   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
 
   // Emit an entry count so the reader can reserve space.
@@ -259,6 +267,7 @@ static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
     switch (T->getTypeID()) {
     default: llvm_unreachable("Unknown type!");
     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;   break;
+    case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;   break;
     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;  break;
     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE; break;
     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80; break;
@@ -284,10 +293,9 @@ static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
     }
     case Type::FunctionTyID: {
       FunctionType *FT = cast<FunctionType>(T);
-      // FUNCTION: [isvararg, attrid, retty, paramty x N]
+      // FUNCTION: [isvararg, retty, paramty x N]
       Code = bitc::TYPE_CODE_FUNCTION;
       TypeVals.push_back(FT->isVarArg());
-      TypeVals.push_back(0);  // FIXME: DEAD: remove in llvm 3.0
       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
@@ -350,7 +358,6 @@ static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 
 static unsigned getEncodedLinkage(const GlobalValue *GV) {
   switch (GV->getLinkage()) {
-  default: llvm_unreachable("Invalid linkage!");
   case GlobalValue::ExternalLinkage:                 return 0;
   case GlobalValue::WeakAnyLinkage:                  return 1;
   case GlobalValue::AppendingLinkage:                return 2;
@@ -368,15 +375,16 @@ static unsigned getEncodedLinkage(const GlobalValue *GV) {
   case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
   case GlobalValue::LinkerPrivateWeakDefAutoLinkage: return 15;
   }
+  llvm_unreachable("Invalid linkage");
 }
 
 static unsigned getEncodedVisibility(const GlobalValue *GV) {
   switch (GV->getVisibility()) {
-  default: llvm_unreachable("Invalid visibility!");
   case GlobalValue::DefaultVisibility:   return 0;
   case GlobalValue::HiddenVisibility:    return 1;
   case GlobalValue::ProtectedVisibility: return 2;
   }
+  llvm_unreachable("Invalid visibility");
 }
 
 // Emit top-level description of module, including target triple, inline asm,
@@ -499,8 +507,8 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
 
   // Emit the function proto information.
   for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
-    // FUNCTION:  [type, callingconv, isproto, paramattr,
-    //             linkage, alignment, section, visibility, gc, unnamed_addr]
+    // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
+    //             section, visibility, gc, unnamed_addr]
     Vals.push_back(VE.getTypeID(F->getType()));
     Vals.push_back(F->getCallingConv());
     Vals.push_back(F->isDeclaration());
@@ -520,6 +528,7 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
   // Emit the alias information.
   for (Module::const_alias_iterator AI = M->alias_begin(), E = M->alias_end();
        AI != E; ++AI) {
+    // ALIAS: [alias type, aliasee val#, linkage, visibility]
     Vals.push_back(VE.getTypeID(AI->getType()));
     Vals.push_back(VE.getValueID(AI->getAliasee()));
     Vals.push_back(getEncodedLinkage(AI));
@@ -819,7 +828,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
       Code = bitc::CST_CODE_FLOAT;
       Type *Ty = CFP->getType();
-      if (Ty->isFloatTy() || Ty->isDoubleTy()) {
+      if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
       } else if (Ty->isX86_FP80Ty()) {
         // api needed to prevent premature destruction
@@ -836,34 +845,56 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
       } else {
         assert (0 && "Unknown FP type!");
       }
-    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
-      const ConstantArray *CA = cast<ConstantArray>(C);
+    } else if (isa<ConstantDataSequential>(C) &&
+               cast<ConstantDataSequential>(C)->isString()) {
+      const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
       // Emit constant strings specially.
-      unsigned NumOps = CA->getNumOperands();
+      unsigned NumElts = Str->getNumElements();
       // If this is a null-terminated string, use the denser CSTRING encoding.
-      if (CA->getOperand(NumOps-1)->isNullValue()) {
+      if (Str->isCString()) {
         Code = bitc::CST_CODE_CSTRING;
-        --NumOps;  // Don't encode the null, which isn't allowed by char6.
+        --NumElts;  // Don't encode the null, which isn't allowed by char6.
       } else {
         Code = bitc::CST_CODE_STRING;
         AbbrevToUse = String8Abbrev;
       }
       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
-      for (unsigned i = 0; i != NumOps; ++i) {
-        unsigned char V = cast<ConstantInt>(CA->getOperand(i))->getZExtValue();
+      for (unsigned i = 0; i != NumElts; ++i) {
+        unsigned char V = Str->getElementAsInteger(i);
         Record.push_back(V);
         isCStr7 &= (V & 128) == 0;
         if (isCStrChar6)
           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
       }
-
+      
       if (isCStrChar6)
         AbbrevToUse = CString6Abbrev;
       else if (isCStr7)
         AbbrevToUse = CString7Abbrev;
-    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
-               isa<ConstantVector>(V)) {
+    } else if (const ConstantDataSequential *CDS = 
+                  dyn_cast<ConstantDataSequential>(C)) {
+      Code = bitc::CST_CODE_DATA;
+      Type *EltTy = CDS->getType()->getElementType();
+      if (isa<IntegerType>(EltTy)) {
+        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
+          Record.push_back(CDS->getElementAsInteger(i));
+      } else if (EltTy->isFloatTy()) {
+        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
+          union { float F; uint32_t I; };
+          F = CDS->getElementAsFloat(i);
+          Record.push_back(I);
+        }
+      } else {
+        assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
+        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
+          union { double F; uint64_t I; };
+          F = CDS->getElementAsDouble(i);
+          Record.push_back(I);
+        }
+      }
+    } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
+               isa<ConstantVector>(C)) {
       Code = bitc::CST_CODE_AGGREGATE;
       for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
         Record.push_back(VE.getValueID(C->getOperand(i)));
@@ -1105,10 +1136,18 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     }
     break;
   case Instruction::Switch:
-    Code = bitc::FUNC_CODE_INST_SWITCH;
-    Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
-    for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
-      Vals.push_back(VE.getValueID(I.getOperand(i)));
+    {
+      Code = bitc::FUNC_CODE_INST_SWITCH;
+      SwitchInst &SI = cast<SwitchInst>(I);
+      Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
+      Vals.push_back(VE.getValueID(SI.getCondition()));
+      Vals.push_back(VE.getValueID(SI.getDefaultDest()));
+      for (SwitchInst::CaseIt i = SI.case_begin(), e = SI.case_end();
+           i != e; ++i) {
+        Vals.push_back(VE.getValueID(i.getCaseValue()));
+        Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
+      }
+    }
     break;
   case Instruction::IndirectBr:
     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
@@ -1146,9 +1185,6 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     Code = bitc::FUNC_CODE_INST_RESUME;
     PushValueAndType(I.getOperand(0), InstID, Vals, VE);
     break;
-  case Instruction::Unwind:
-    Code = bitc::FUNC_CODE_INST_UNWIND;
-    break;
   case Instruction::Unreachable:
     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
@@ -1573,6 +1609,102 @@ static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
   Stream.ExitBlock();
 }
 
+// Sort the Users based on the order in which the reader parses the bitcode 
+// file.
+static bool bitcodereader_order(const User *lhs, const User *rhs) {
+  // TODO: Implement.
+  return true;
+}
+
+static void WriteUseList(const Value *V, const ValueEnumerator &VE,
+                         BitstreamWriter &Stream) {
+
+  // One or zero uses can't get out of order.
+  if (V->use_empty() || V->hasNUses(1))
+    return;
+
+  // Make a copy of the in-memory use-list for sorting.
+  unsigned UseListSize = std::distance(V->use_begin(), V->use_end());
+  SmallVector<const User*, 8> UseList;
+  UseList.reserve(UseListSize);
+  for (Value::const_use_iterator I = V->use_begin(), E = V->use_end();
+       I != E; ++I) {
+    const User *U = *I;
+    UseList.push_back(U);
+  }
+
+  // Sort the copy based on the order read by the BitcodeReader.
+  std::sort(UseList.begin(), UseList.end(), bitcodereader_order);
+
+  // TODO: Generate a diff between the BitcodeWriter in-memory use-list and the
+  // sorted list (i.e., the expected BitcodeReader in-memory use-list).
+
+  // TODO: Emit the USELIST_CODE_ENTRYs.
+}
+
+static void WriteFunctionUseList(const Function *F, ValueEnumerator &VE,
+                                 BitstreamWriter &Stream) {
+  VE.incorporateFunction(*F);
+
+  for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
+       AI != AE; ++AI)
+    WriteUseList(AI, VE, Stream);
+  for (Function::const_iterator BB = F->begin(), FE = F->end(); BB != FE;
+       ++BB) {
+    WriteUseList(BB, VE, Stream);
+    for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); II != IE;
+         ++II) {
+      WriteUseList(II, VE, Stream);
+      for (User::const_op_iterator OI = II->op_begin(), E = II->op_end();
+           OI != E; ++OI) {
+        if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
+            isa<InlineAsm>(*OI))
+          WriteUseList(*OI, VE, Stream);
+      }
+    }
+  }
+  VE.purgeFunction();
+}
+
+// Emit use-lists.
+static void WriteModuleUseLists(const Module *M, ValueEnumerator &VE,
+                                BitstreamWriter &Stream) {
+  Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
+
+  // XXX: this modifies the module, but in a way that should never change the
+  // behavior of any pass or codegen in LLVM. The problem is that GVs may
+  // contain entries in the use_list that do not exist in the Module and are
+  // not stored in the .bc file.
+  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
+       I != E; ++I)
+    I->removeDeadConstantUsers();
+  
+  // Write the global variables.
+  for (Module::const_global_iterator GI = M->global_begin(), 
+         GE = M->global_end(); GI != GE; ++GI) {
+    WriteUseList(GI, VE, Stream);
+
+    // Write the global variable initializers.
+    if (GI->hasInitializer())
+      WriteUseList(GI->getInitializer(), VE, Stream);
+  }
+
+  // Write the functions.
+  for (Module::const_iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI) {
+    WriteUseList(FI, VE, Stream);
+    if (!FI->isDeclaration())
+      WriteFunctionUseList(FI, VE, Stream);
+  }
+
+  // Write the aliases.
+  for (Module::const_alias_iterator AI = M->alias_begin(), AE = M->alias_end();
+       AI != AE; ++AI) {
+    WriteUseList(AI, VE, Stream);
+    WriteUseList(AI->getAliasee(), VE, Stream);
+  }
+
+  Stream.ExitBlock();
+}
 
 /// WriteModule - Emit the specified module to the bitstream.
 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
@@ -1607,17 +1739,21 @@ static void WriteModule(const Module *M, BitstreamWriter &Stream) {
   // Emit metadata.
   WriteModuleMetadata(M, VE, Stream);
 
-  // Emit function bodies.
-  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
-    if (!F->isDeclaration())
-      WriteFunction(*F, VE, Stream);
-
   // Emit metadata.
   WriteModuleMetadataStore(M, Stream);
 
   // Emit names for globals/functions etc.
   WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
 
+  // Emit use-lists.
+  if (EnablePreserveUseListOrdering)
+    WriteModuleUseLists(M, VE, Stream);
+
+  // Emit function bodies.
+  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F)
+    if (!F->isDeclaration())
+      WriteFunction(*F, VE, Stream);
+
   Stream.ExitBlock();
 }
 
@@ -1639,7 +1775,17 @@ enum {
   DarwinBCHeaderSize = 5*4
 };
 
-static void EmitDarwinBCHeader(BitstreamWriter &Stream, const Triple &TT) {
+static void WriteInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
+                               uint32_t &Position) {
+  Buffer[Position + 0] = (unsigned char) (Value >>  0);
+  Buffer[Position + 1] = (unsigned char) (Value >>  8);
+  Buffer[Position + 2] = (unsigned char) (Value >> 16);
+  Buffer[Position + 3] = (unsigned char) (Value >> 24);
+  Position += 4;
+}
+
+static void EmitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
+                                         const Triple &TT) {
   unsigned CPUType = ~0U;
 
   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
@@ -1666,63 +1812,55 @@ static void EmitDarwinBCHeader(BitstreamWriter &Stream, const Triple &TT) {
     CPUType = DARWIN_CPU_TYPE_ARM;
 
   // Traditional Bitcode starts after header.
+  assert(Buffer.size() >= DarwinBCHeaderSize &&
+         "Expected header size to be reserved");
   unsigned BCOffset = DarwinBCHeaderSize;
+  unsigned BCSize = Buffer.size()-DarwinBCHeaderSize;
 
-  Stream.Emit(0x0B17C0DE, 32);
-  Stream.Emit(0         , 32);  // Version.
-  Stream.Emit(BCOffset  , 32);
-  Stream.Emit(0         , 32);  // Filled in later.
-  Stream.Emit(CPUType   , 32);
-}
-
-/// EmitDarwinBCTrailer - Emit the darwin epilog after the bitcode file and
-/// finalize the header.
-static void EmitDarwinBCTrailer(BitstreamWriter &Stream, unsigned BufferSize) {
-  // Update the size field in the header.
-  Stream.BackpatchWord(DarwinBCSizeFieldOffset, BufferSize-DarwinBCHeaderSize);
+  // Write the magic and version.
+  unsigned Position = 0;
+  WriteInt32ToBuffer(0x0B17C0DE , Buffer, Position);
+  WriteInt32ToBuffer(0          , Buffer, Position); // Version.
+  WriteInt32ToBuffer(BCOffset   , Buffer, Position);
+  WriteInt32ToBuffer(BCSize     , Buffer, Position);
+  WriteInt32ToBuffer(CPUType    , Buffer, Position);
 
   // If the file is not a multiple of 16 bytes, insert dummy padding.
-  while (BufferSize & 15) {
-    Stream.Emit(0, 8);
-    ++BufferSize;
-  }
+  while (Buffer.size() & 15)
+    Buffer.push_back(0);
 }
 
-
 /// WriteBitcodeToFile - Write the specified module to the specified output
 /// stream.
 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out) {
-  std::vector<unsigned char> Buffer;
-  BitstreamWriter Stream(Buffer);
-
+  SmallVector<char, 1024> Buffer;
   Buffer.reserve(256*1024);
 
-  WriteBitcodeToStream( M, Stream );
-
-  // Write the generated bitstream to "Out".
-  Out.write((char*)&Buffer.front(), Buffer.size());
-}
-
-/// WriteBitcodeToStream - Write the specified module to the specified output
-/// stream.
-void llvm::WriteBitcodeToStream(const Module *M, BitstreamWriter &Stream) {
-  // If this is darwin or another generic macho target, emit a file header and
-  // trailer if needed.
+  // If this is darwin or another generic macho target, reserve space for the
+  // header.
   Triple TT(M->getTargetTriple());
   if (TT.isOSDarwin())
-    EmitDarwinBCHeader(Stream, TT);
-
-  // Emit the file header.
-  Stream.Emit((unsigned)'B', 8);
-  Stream.Emit((unsigned)'C', 8);
-  Stream.Emit(0x0, 4);
-  Stream.Emit(0xC, 4);
-  Stream.Emit(0xE, 4);
-  Stream.Emit(0xD, 4);
-
-  // Emit the module.
-  WriteModule(M, Stream);
+    Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
+
+  // Emit the module into the buffer.
+  {
+    BitstreamWriter Stream(Buffer);
+
+    // Emit the file header.
+    Stream.Emit((unsigned)'B', 8);
+    Stream.Emit((unsigned)'C', 8);
+    Stream.Emit(0x0, 4);
+    Stream.Emit(0xC, 4);
+    Stream.Emit(0xE, 4);
+    Stream.Emit(0xD, 4);
+
+    // Emit the module.
+    WriteModule(M, Stream);
+  }
 
   if (TT.isOSDarwin())
-    EmitDarwinBCTrailer(Stream, Stream.getBuffer().size());
+    EmitDarwinBCHeaderAndTrailer(Buffer, TT);
+
+  // Write the generated bitstream to "Out".
+  Out.write((char*)&Buffer.front(), Buffer.size());
 }
diff --git a/lib/Bitcode/Writer/CMakeLists.txt b/lib/Bitcode/Writer/CMakeLists.txt
index 3cf9056..f097b09 100644
--- a/lib/Bitcode/Writer/CMakeLists.txt
+++ b/lib/Bitcode/Writer/CMakeLists.txt
@@ -4,8 +4,3 @@ add_llvm_library(LLVMBitWriter
   BitcodeWriterPass.cpp
   ValueEnumerator.cpp
   )
-
-add_llvm_library_dependencies(LLVMBitWriter
-  LLVMCore
-  LLVMSupport
-  )
diff --git a/lib/Bitcode/Writer/LLVMBuild.txt b/lib/Bitcode/Writer/LLVMBuild.txt
new file mode 100644
index 0000000..7d9e1de
--- /dev/null
+++ b/lib/Bitcode/Writer/LLVMBuild.txt
@@ -0,0 +1,22 @@
+;===- ./lib/Bitcode/Writer/LLVMBuild.txt -----------------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = BitWriter
+parent = Bitcode
+required_libraries = Core Support
diff --git a/lib/Bitcode/Writer/ValueEnumerator.cpp b/lib/Bitcode/Writer/ValueEnumerator.cpp
index 9ae9905..1ed9004 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -19,6 +19,8 @@
 #include "llvm/Module.h"
 #include "llvm/ValueSymbolTable.h"
 #include "llvm/Instructions.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 using namespace llvm;
 
@@ -107,7 +109,6 @@ ValueEnumerator::ValueEnumerator(const Module *M) {
   OptimizeConstants(FirstConstant, Values.size());
 }
 
-
 unsigned ValueEnumerator::getInstructionID(const Instruction *Inst) const {
   InstructionMapType::const_iterator I = InstructionMap.find(Inst);
   assert(I != InstructionMap.end() && "Instruction is not mapped!");
@@ -130,6 +131,43 @@ unsigned ValueEnumerator::getValueID(const Value *V) const {
   return I->second-1;
 }
 
+void ValueEnumerator::dump() const {
+  print(dbgs(), ValueMap, "Default");
+  dbgs() << '\n';
+  print(dbgs(), MDValueMap, "MetaData");
+  dbgs() << '\n';
+}
+
+void ValueEnumerator::print(raw_ostream &OS, const ValueMapType &Map,
+                            const char *Name) const {
+
+  OS << "Map Name: " << Name << "\n";
+  OS << "Size: " << Map.size() << "\n";
+  for (ValueMapType::const_iterator I = Map.begin(),
+         E = Map.end(); I != E; ++I) {
+
+    const Value *V = I->first;
+    if (V->hasName())
+      OS << "Value: " << V->getName();
+    else
+      OS << "Value: [null]\n";
+    V->dump();
+
+    OS << " Uses(" << std::distance(V->use_begin(),V->use_end()) << "):";
+    for (Value::const_use_iterator UI = V->use_begin(), UE = V->use_end();
+         UI != UE; ++UI) {
+      if (UI != V->use_begin())
+        OS << ",";
+      if((*UI)->hasName())
+        OS << " " << (*UI)->getName();
+      else
+        OS << " [null]";
+
+    }
+    OS <<  "\n\n";
+  }
+}
+
 // Optimize constant ordering.
 namespace {
   struct CstSortPredicate {
@@ -283,10 +321,6 @@ void ValueEnumerator::EnumerateValue(const Value *V) {
   if (const Constant *C = dyn_cast<Constant>(V)) {
     if (isa<GlobalValue>(C)) {
       // Initializers for globals are handled explicitly elsewhere.
-    } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
-      // Do not enumerate the initializers for an array of simple characters.
-      // The initializers just pollute the value table, and we emit the strings
-      // specially.
     } else if (C->getNumOperands()) {
       // If a constant has operands, enumerate them.  This makes sure that if a
       // constant has uses (for example an array of const ints), that they are
diff --git a/lib/Bitcode/Writer/ValueEnumerator.h b/lib/Bitcode/Writer/ValueEnumerator.h
index b6fc920..a6ca536 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.h
+++ b/lib/Bitcode/Writer/ValueEnumerator.h
@@ -32,6 +32,7 @@ class NamedMDNode;
 class AttrListPtr;
 class ValueSymbolTable;
 class MDSymbolTable;
+class raw_ostream;
 
 class ValueEnumerator {
 public:
@@ -83,6 +84,9 @@ private:
 public:
   ValueEnumerator(const Module *M);
 
+  void dump() const;
+  void print(raw_ostream &OS, const ValueMapType &Map, const char *Name) const;
+
   unsigned getValueID(const Value *V) const;
 
   unsigned getTypeID(Type *T) const {