Copy Bitwriter to generate PNaClBitwriter.

lib/Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp

-//===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
+//===--- Bitcode/NaCl/Writer/NaClBitcodeWriter.cpp - Bitcode Writer -------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Bitcode writer implementation.
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Bitcode/ReaderWriter.h"
-#include "ValueEnumerator.h"
+#include "llvm/Bitcode/NaCl/NaClReaderWriter.h"
+#include "NaClValueEnumerator.h"
 #include "llvm/ADT/Triple.h"
-#include "llvm/Bitcode/BitstreamWriter.h"
+#include "llvm/Bitcode/NaCl/NaClBitstreamWriter.h"
 #include "llvm/Bitcode/LLVMBitCodes.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/ValueSymbolTable.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cctype>
 #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 {
   // VALUE_SYMTAB_BLOCK abbrev id's.
   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
   VST_ENTRY_7_ABBREV,
   VST_ENTRY_6_ABBREV,
   VST_BBENTRY_6_ABBREV,
 
   // CONSTANTS_BLOCK abbrev id's.
@@ skipping 89 matching lines @@
 
 static unsigned GetEncodedSynchScope(SynchronizationScope SynchScope) {
   switch (SynchScope) {
   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
   }
   llvm_unreachable("Invalid synch scope");
 }
 
 static void WriteStringRecord(unsigned Code, StringRef Str,
-                              unsigned AbbrevToUse, BitstreamWriter &Stream) {
+                              unsigned AbbrevToUse, NaClBitstreamWriter &Stream) {
   SmallVector<unsigned, 64> Vals;
 
   // Code: [strchar x N]
   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
       AbbrevToUse = 0;
     Vals.push_back(Str[i]);
   }
 
   // Emit the finished record.
   Stream.EmitRecord(Code, Vals, AbbrevToUse);
 }
 
-static void WriteAttributeGroupTable(const ValueEnumerator &VE,
-                                     BitstreamWriter &Stream) {
+static void WriteAttributeGroupTable(const NaClValueEnumerator &VE,
+                                     NaClBitstreamWriter &Stream) {
   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
   if (AttrGrps.empty()) return;
 
   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
     AttributeSet AS = AttrGrps[i];
     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
       AttributeSet A = AS.getSlotAttributes(i);
@@ skipping 26 matching lines @@
       }
 
       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
       Record.clear();
     }
   }
 
   Stream.ExitBlock();
 }
 
-static void WriteAttributeTable(const ValueEnumerator &VE,
-                                BitstreamWriter &Stream) {
+static void WriteAttributeTable(const NaClValueEnumerator &VE,
+                                NaClBitstreamWriter &Stream) {
   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
   if (Attrs.empty()) return;
 
   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
     const AttributeSet &A = Attrs[i];
     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
 
     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
     Record.clear();
   }
 
   Stream.ExitBlock();
 }
 
 /// WriteTypeTable - Write out the type table for a module.
-static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
-  const ValueEnumerator::TypeList &TypeList = VE.getTypes();
+static void WriteTypeTable(const NaClValueEnumerator &VE,
+                           NaClBitstreamWriter &Stream) {
+  const NaClValueEnumerator::TypeList &TypeList = VE.getTypes();
 
   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, NumBits));
@@ skipping 182 matching lines @@
     case GlobalVariable::GeneralDynamicTLSModel: return 1;
     case GlobalVariable::LocalDynamicTLSModel:   return 2;
     case GlobalVariable::InitialExecTLSModel:    return 3;
     case GlobalVariable::LocalExecTLSModel:      return 4;
   }
   llvm_unreachable("Invalid TLS model");
 }
 
 // Emit top-level description of module, including target triple, inline asm,
 // descriptors for global variables, and function prototype info.
-static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
-                            BitstreamWriter &Stream) {
+static void WriteModuleInfo(const Module *M, const NaClValueEnumerator &VE,
+                            NaClBitstreamWriter &Stream) {
   // Emit various pieces of data attached to a module.
   if (!M->getTargetTriple().empty())
     WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
                       0/*TODO*/, Stream);
   if (!M->getDataLayout().empty())
     WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
                       0/*TODO*/, Stream);
   if (!M->getModuleInlineAsm().empty())
     WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
                       0/*TODO*/, Stream);
@@ skipping 156 matching lines @@
     if (FPMO->hasNoSignedZeros())
       Flags |= FastMathFlags::NoSignedZeros;
     if (FPMO->hasAllowReciprocal())
       Flags |= FastMathFlags::AllowReciprocal;
   }
 
   return Flags;
 }
 
 static void WriteMDNode(const MDNode *N,
-                        const ValueEnumerator &VE,
-                        BitstreamWriter &Stream,
+                        const NaClValueEnumerator &VE,
+                        NaClBitstreamWriter &Stream,
                         SmallVector<uint64_t, 64> &Record) {
   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
     if (N->getOperand(i)) {
       Record.push_back(VE.getTypeID(N->getOperand(i)->getType()));
       Record.push_back(VE.getValueID(N->getOperand(i)));
     } else {
       Record.push_back(VE.getTypeID(Type::getVoidTy(N->getContext())));
       Record.push_back(0);
     }
   }
   unsigned MDCode = N->isFunctionLocal() ? bitc::METADATA_FN_NODE :
                                            bitc::METADATA_NODE;
   Stream.EmitRecord(MDCode, Record, 0);
   Record.clear();
 }
 
 static void WriteModuleMetadata(const Module *M,
-                                const ValueEnumerator &VE,
-                                BitstreamWriter &Stream) {
-  const ValueEnumerator::ValueList &Vals = VE.getMDValues();
+                                const NaClValueEnumerator &VE,
+                                NaClBitstreamWriter &Stream) {
+  const NaClValueEnumerator::ValueList &Vals = VE.getMDValues();
   bool StartedMetadataBlock = false;
   unsigned MDSAbbrev = 0;
   SmallVector<uint64_t, 64> Record;
   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
 
     if (const MDNode *N = dyn_cast<MDNode>(Vals[i].first)) {
       if (!N->isFunctionLocal() || !N->getFunction()) {
         if (!StartedMetadataBlock) {
           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
           StartedMetadataBlock = true;
@@ skipping 43 matching lines @@
       Record.push_back(VE.getValueID(NMD->getOperand(i)));
     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
     Record.clear();
   }
 
   if (StartedMetadataBlock)
     Stream.ExitBlock();
 }
 
 static void WriteFunctionLocalMetadata(const Function &F,
-                                       const ValueEnumerator &VE,
-                                       BitstreamWriter &Stream) {
+                                       const NaClValueEnumerator &VE,
+                                       NaClBitstreamWriter &Stream) {
   bool StartedMetadataBlock = false;
   SmallVector<uint64_t, 64> Record;
   const SmallVector<const MDNode *, 8> &Vals = VE.getFunctionLocalMDValues();
   for (unsigned i = 0, e = Vals.size(); i != e; ++i)
     if (const MDNode *N = Vals[i])
       if (N->isFunctionLocal() && N->getFunction() == &F) {
         if (!StartedMetadataBlock) {
           Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
           StartedMetadataBlock = true;
         }
         WriteMDNode(N, VE, Stream, Record);
       }
 
   if (StartedMetadataBlock)
     Stream.ExitBlock();
 }
 
 static void WriteMetadataAttachment(const Function &F,
-                                    const ValueEnumerator &VE,
-                                    BitstreamWriter &Stream) {
+                                    const NaClValueEnumerator &VE,
+                                    NaClBitstreamWriter &Stream) {
   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
 
   // Write metadata attachments
   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
   SmallVector<std::pair<unsigned, MDNode*>, 4> MDs;
 
   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
@@ skipping 10 matching lines @@
         Record.push_back(MDs[i].first);
         Record.push_back(VE.getValueID(MDs[i].second));
       }
       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
       Record.clear();
     }
 
   Stream.ExitBlock();
 }
 
-static void WriteModuleMetadataStore(const Module *M, BitstreamWriter &Stream) {
+static void WriteModuleMetadataStore(const Module *M, NaClBitstreamWriter &Stream) {
   SmallVector<uint64_t, 64> Record;
 
   // Write metadata kinds
   // METADATA_KIND - [n x [id, name]]
   SmallVector<StringRef, 8> Names;
   M->getMDKindNames(Names);
 
   if (Names.empty()) return;
 
   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
@@ skipping 39 matching lines @@
 
     const uint64_t *RawWords = Val.getRawData();
     for (unsigned i = 0; i != NWords; ++i) {
       emitSignedInt64(Vals, RawWords[i]);
     }
     Code = bitc::CST_CODE_WIDE_INTEGER;
   }
 }
 
 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
-                           const ValueEnumerator &VE,
-                           BitstreamWriter &Stream, bool isGlobal) {
+                           const NaClValueEnumerator &VE,
+                           NaClBitstreamWriter &Stream, bool isGlobal) {
   if (FirstVal == LastVal) return;
 
   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
 
   unsigned AggregateAbbrev = 0;
   unsigned String8Abbrev = 0;
   unsigned CString7Abbrev = 0;
   unsigned CString6Abbrev = 0;
   // If this is a constant pool for the module, emit module-specific abbrevs.
   if (isGlobal) {
@@ skipping 19 matching lines @@
     // Abbrev for CST_CODE_CSTRING.
     Abbv = new BitCodeAbbrev();
     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
     CString6Abbrev = Stream.EmitAbbrev(Abbv);
   }
 
   SmallVector<uint64_t, 64> Record;
 
-  const ValueEnumerator::ValueList &Vals = VE.getValues();
+  const NaClValueEnumerator::ValueList &Vals = VE.getValues();
   Type *LastTy = 0;
   for (unsigned i = FirstVal; i != LastVal; ++i) {
     const Value *V = Vals[i].first;
     // If we need to switch types, do so now.
     if (V->getType() != LastTy) {
       LastTy = V->getType();
       Record.push_back(VE.getTypeID(LastTy));
       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
                         CONSTANTS_SETTYPE_ABBREV);
       Record.clear();
@@ skipping 184 matching lines @@
 #endif
       llvm_unreachable("Unknown constant!");
     }
     Stream.EmitRecord(Code, Record, AbbrevToUse);
     Record.clear();
   }
 
   Stream.ExitBlock();
 }
 
-static void WriteModuleConstants(const ValueEnumerator &VE,
-                                 BitstreamWriter &Stream) {
-  const ValueEnumerator::ValueList &Vals = VE.getValues();
+static void WriteModuleConstants(const NaClValueEnumerator &VE,
+                                 NaClBitstreamWriter &Stream) {
+  const NaClValueEnumerator::ValueList &Vals = VE.getValues();
 
   // Find the first constant to emit, which is the first non-globalvalue value.
   // We know globalvalues have been emitted by WriteModuleInfo.
   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
     if (!isa<GlobalValue>(Vals[i].first)) {
       WriteConstants(i, Vals.size(), VE, Stream, true);
       return;
     }
   }
 }
 
 /// PushValueAndType - The file has to encode both the value and type id for
 /// many values, because we need to know what type to create for forward
 /// references.  However, most operands are not forward references, so this type
 /// field is not needed.
 ///
 /// This function adds V's value ID to Vals.  If the value ID is higher than the
 /// instruction ID, then it is a forward reference, and it also includes the
 /// type ID.  The value ID that is written is encoded relative to the InstID.
 static bool PushValueAndType(const Value *V, unsigned InstID,
                              SmallVector<unsigned, 64> &Vals,
-                             ValueEnumerator &VE) {
+                             NaClValueEnumerator &VE) {
   unsigned ValID = VE.getValueID(V);
   // Make encoding relative to the InstID.
   Vals.push_back(InstID - ValID);
   if (ValID >= InstID) {
     Vals.push_back(VE.getTypeID(V->getType()));
     return true;
   }
   return false;
 }
 
 /// pushValue - Like PushValueAndType, but where the type of the value is
 /// omitted (perhaps it was already encoded in an earlier operand).
 static void pushValue(const Value *V, unsigned InstID,
                       SmallVector<unsigned, 64> &Vals,
-                      ValueEnumerator &VE) {
+                      NaClValueEnumerator &VE) {
   unsigned ValID = VE.getValueID(V);
   Vals.push_back(InstID - ValID);
 }
 
 static void pushValue64(const Value *V, unsigned InstID,
                         SmallVector<uint64_t, 128> &Vals,
-                        ValueEnumerator &VE) {
+                        NaClValueEnumerator &VE) {
   uint64_t ValID = VE.getValueID(V);
   Vals.push_back(InstID - ValID);
 }
 
 static void pushValueSigned(const Value *V, unsigned InstID,
                             SmallVector<uint64_t, 128> &Vals,
-                            ValueEnumerator &VE) {
+                            NaClValueEnumerator &VE) {
   unsigned ValID = VE.getValueID(V);
   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
   emitSignedInt64(Vals, diff);
 }
 
 /// WriteInstruction - Emit an instruction to the specified stream.
 static void WriteInstruction(const Instruction &I, unsigned InstID,
-                             ValueEnumerator &VE, BitstreamWriter &Stream,
+                             NaClValueEnumerator &VE, NaClBitstreamWriter &Stream,
                              SmallVector<unsigned, 64> &Vals) {
   unsigned Code = 0;
   unsigned AbbrevToUse = 0;
   VE.setInstructionID(&I);
   switch (I.getOpcode()) {
   default:
     if (Instruction::isCast(I.getOpcode())) {
       Code = bitc::FUNC_CODE_INST_CAST;
       if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE))
         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
@@ skipping 336 matching lines @@
     Vals.push_back(VE.getTypeID(I.getType())); // restype.
     break;
   }
 
   Stream.EmitRecord(Code, Vals, AbbrevToUse);
   Vals.clear();
 }
 
 // Emit names for globals/functions etc.
 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
-                                  const ValueEnumerator &VE,
-                                  BitstreamWriter &Stream) {
+                                  const NaClValueEnumerator &VE,
+                                  NaClBitstreamWriter &Stream) {
   if (VST.empty()) return;
   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
 
   // FIXME: Set up the abbrev, we know how many values there are!
   // FIXME: We know if the type names can use 7-bit ascii.
   SmallVector<unsigned, 64> NameVals;
 
   for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
        SI != SE; ++SI) {
 
@@ skipping 35 matching lines @@
       NameVals.push_back((unsigned char)*P);
 
     // Emit the finished record.
     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
     NameVals.clear();
   }
   Stream.ExitBlock();
 }
 
 /// WriteFunction - Emit a function body to the module stream.
-static void WriteFunction(const Function &F, ValueEnumerator &VE,
-                          BitstreamWriter &Stream) {
+static void WriteFunction(const Function &F, NaClValueEnumerator &VE,
+                          NaClBitstreamWriter &Stream) {
   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
   VE.incorporateFunction(F);
 
   SmallVector<unsigned, 64> Vals;
 
   // Emit the number of basic blocks, so the reader can create them ahead of
   // time.
   Vals.push_back(VE.getBasicBlocks().size());
   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
   Vals.clear();
@@ skipping 50 matching lines @@
   // Emit names for all the instructions etc.
   WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
 
   if (NeedsMetadataAttachment)
     WriteMetadataAttachment(F, VE, Stream);
   VE.purgeFunction();
   Stream.ExitBlock();
 }
 
 // Emit blockinfo, which defines the standard abbreviations etc.
-static void WriteBlockInfo(const ValueEnumerator &VE, BitstreamWriter &Stream) {
+static void WriteBlockInfo(const NaClValueEnumerator &VE, NaClBitstreamWriter &Stream) {
   // We only want to emit block info records for blocks that have multiple
   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
   // Other blocks can define their abbrevs inline.
   Stream.EnterBlockInfoBlock(2);
 
   { // 8-bit fixed-width VST_ENTRY/VST_BBENTRY strings.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
@@ skipping 139 matching lines @@
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
       llvm_unreachable("Unexpected abbrev ordering!");
   }
 
   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) {
+static void WriteModule(const Module *M, NaClBitstreamWriter &Stream) {
   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
 
   SmallVector<unsigned, 1> Vals;
   unsigned CurVersion = 1;
   Vals.push_back(CurVersion);
   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
 
   // Analyze the module, enumerating globals, functions, etc.
-  ValueEnumerator VE(M);
+  NaClValueEnumerator VE(M);
 
   // Emit blockinfo, which defines the standard abbreviations etc.
   WriteBlockInfo(VE, Stream);
 
   // Emit information about attribute groups.
   WriteAttributeGroupTable(VE, Stream);
 
   // Emit information about parameter attributes.
   WriteAttributeTable(VE, Stream);
 
   // Emit information describing all of the types in the module.
   WriteTypeTable(VE, Stream);
 
   // Emit top-level description of module, including target triple, inline asm,
   // descriptors for global variables, and function prototype info.
   WriteModuleInfo(M, VE, Stream);
 
   // Emit constants.
   WriteModuleConstants(VE, Stream);
 
   // Emit metadata.
   WriteModuleMetadata(M, 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();
 }
 
 /// EmitDarwinBCHeader - If generating a bc file on darwin, we have to emit a
 /// header and trailer to make it compatible with the system archiver.  To do
@@ skipping 63 matching lines @@
   WriteInt32ToBuffer(BCSize     , Buffer, Position);
   WriteInt32ToBuffer(CPUType    , Buffer, Position);
 
   // If the file is not a multiple of 16 bytes, insert dummy padding.
   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) {
+void llvm::NaClWriteBitcodeToFile(const Module *M, raw_ostream &Out) {
   SmallVector<char, 0> Buffer;
   Buffer.reserve(256*1024);
 
   // Convert Deplib info to metadata
   M->convertLibraryListToMetadata(); // @LOCALMOD
 
   // If this is darwin or another generic macho target, reserve space for the
   // header.
   Triple TT(M->getTargetTriple());
   if (TT.isOSDarwin())
     Buffer.insert(Buffer.begin(), DarwinBCHeaderSize, 0);
 
   // Emit the module into the buffer.
   {
-    BitstreamWriter Stream(Buffer);
+    NaClBitstreamWriter 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())
     EmitDarwinBCHeaderAndTrailer(Buffer, TT);
 
   // Write the generated bitstream to "Out".
   Out.write((char*)&Buffer.front(), Buffer.size());
 }