Implemented the bulk of the functionality. Cleaned up the code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14113 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 335 insertions, 175 deletions

diff --git a/lib/Bytecode/Analyzer/Parser.cpp b/lib/Bytecode/Analyzer/Parser.cpp
index 743db6c315..80800e75a6 100644
--- a/lib/Bytecode/Analyzer/Parser.cpp
+++ b/lib/Bytecode/Analyzer/Parser.cpp
@@ -1,4 +1,4 @@
-//===- Reader.cpp - Code to read bytecode files ---------------------------===//
+//===- Parser.cpp - Code to parse bytecode files --------------------------===//
 // 
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,7 +7,7 @@
 // 
 //===----------------------------------------------------------------------===//
 //
-// This library implements the functionality defined in llvm/Bytecode/Reader.h
+// This library implements the functionality defined in llvm/Bytecode/Parser.h
 //
 // Note that this library should be as fast as possible, reentrant, and 
 // threadsafe!!
@@ -17,7 +17,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "AnalyzerInternals.h"
-#include "ReaderPrimitives.h"
 #include "llvm/Module.h"
 #include "llvm/Bytecode/Format.h"
 #include "Support/StringExtras.h"
@@ -37,40 +36,128 @@ using namespace llvm;
 #define BCR_TRACE(n, X)
 #endif
 
-#define PARSE_ERROR(inserters) \
-  { \
+#define PARSE_ERROR(inserters) { \
     std::ostringstream errormsg; \
     errormsg << inserters; \
     if ( ! handler->handleError( errormsg.str() ) ) \
       throw std::string(errormsg.str()); \
   }
 
+inline bool AbstractBytecodeParser::moreInBlock() {
+  return At < BlockEnd;
+}
 
-inline void AbstractBytecodeParser::readBlock(const unsigned char *&Buf,
-			       const unsigned char *EndBuf, 
-			       unsigned &Type, unsigned &Size)
-{
-  Type = read(Buf, EndBuf);
-  Size = read(Buf, EndBuf);
+inline void AbstractBytecodeParser::checkPastBlockEnd(const char * block_name) {
+  if ( At > BlockEnd )
+    PARSE_ERROR("Attempt to read past the end of " << block_name << " block.");
 }
 
-const Type *AbstractBytecodeParser::getType(unsigned ID) {
-  //cerr << "Looking up Type ID: " << ID << "\n";
+inline void AbstractBytecodeParser::align32() {
+  BufPtr Save = At;
+  At = (const unsigned char *)((unsigned long)(At+3) & (~3UL));
+  if ( reportAlignment && At > Save ) handler->handleAlignment( At - Save );
+  if (At > BlockEnd) 
+    throw std::string("Ran out of data while aligning!");
+}
+
+inline unsigned AbstractBytecodeParser::read_uint() {
+  if (At+4 > BlockEnd) 
+    throw std::string("Ran out of data reading uint!");
+  At += 4;
+  return At[-4] | (At[-3] << 8) | (At[-2] << 16) | (At[-1] << 24);
+}
+
+inline unsigned AbstractBytecodeParser::read_vbr_uint() {
+  unsigned Shift = 0;
+  unsigned Result = 0;
+  BufPtr Save = At;
+  
+  do {
+    if (At == BlockEnd) 
+      throw std::string("Ran out of data reading vbr_uint!");
+    Result |= (unsigned)((*At++) & 0x7F) << Shift;
+    Shift += 7;
+  } while (At[-1] & 0x80);
+  if (reportVBR)
+    handler->handleVBR32(At-Save);
+  return Result;
+}
+
+inline uint64_t AbstractBytecodeParser::read_vbr_uint64() {
+  unsigned Shift = 0;
+  uint64_t Result = 0;
+  BufPtr Save = At;
+  
+  do {
+    if (At == BlockEnd) 
+      throw std::string("Ran out of data reading vbr_uint64!");
+    Result |= (uint64_t)((*At++) & 0x7F) << Shift;
+    Shift += 7;
+  } while (At[-1] & 0x80);
+  if (reportVBR)
+    handler->handleVBR64(At-Save);
+  return Result;
+}
 
-  if (ID < Type::FirstDerivedTyID)
-    if (const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID))
-      return T;   // Asked for a primitive type...
+inline int64_t AbstractBytecodeParser::read_vbr_int64() {
+  uint64_t R = read_vbr_uint64();
+  if (R & 1) {
+    if (R != 1)
+      return -(int64_t)(R >> 1);
+    else   // There is no such thing as -0 with integers.  "-0" really means
+           // 0x8000000000000000.
+      return 1LL << 63;
+  } else
+    return  (int64_t)(R >> 1);
+}
 
-  // Otherwise, derived types need offset...
-  ID -= Type::FirstDerivedTyID;
+inline std::string AbstractBytecodeParser::read_str() {
+  unsigned Size = read_vbr_uint();
+  const unsigned char *OldAt = At;
+  At += Size;
+  if (At > BlockEnd)             // Size invalid?
+    throw std::string("Ran out of data reading a string!");
+  return std::string((char*)OldAt, Size);
+}
+
+inline void AbstractBytecodeParser::read_data(void *Ptr, void *End) {
+  unsigned char *Start = (unsigned char *)Ptr;
+  unsigned Amount = (unsigned char *)End - Start;
+  if (At+Amount > BlockEnd) 
+    throw std::string("Ran out of data!");
+  std::copy(At, At+Amount, Start);
+  At += Amount;
+}
 
-  if (!CompactionTypeTable.empty()) {
-    if (ID >= CompactionTypeTable.size())
-      PARSE_ERROR("Type ID out of range for compaction table!");
-    return CompactionTypeTable[ID];
+inline void AbstractBytecodeParser::readBlock(unsigned &Type, unsigned &Size) {
+  Type = read_uint();
+  Size = read_uint();
+  BlockStart = At;
+  if ( At + Size > BlockEnd )
+    throw std::string("Attempt to size a block past end of memory");
+  BlockEnd = At + Size;
+  if ( reportBlocks ) {
+    handler->handleBlock( Type, BlockStart, Size );
   }
+}
+
+const Type *AbstractBytecodeParser::getType(unsigned ID) {
+//cerr << "Looking up Type ID: " << ID << "\n";
+
+if (ID < Type::FirstDerivedTyID)
+  if (const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID))
+    return T;   // Asked for a primitive type...
+
+// Otherwise, derived types need offset...
+ID -= Type::FirstDerivedTyID;
 
-  // Is it a module-level type?
+if (!CompactionTypeTable.empty()) {
+  if (ID >= CompactionTypeTable.size())
+    PARSE_ERROR("Type ID out of range for compaction table!");
+  return CompactionTypeTable[ID];
+}
+
+// Is it a module-level type?
   if (ID < ModuleTypes.size())
     return ModuleTypes[ID].get();
 
@@ -83,12 +170,12 @@ const Type *AbstractBytecodeParser::getType(unsigned ID) {
   return Type::VoidTy;
 }
 
-bool AbstractBytecodeParser::ParseInstruction(BufPtr& Buf, BufPtr EndBuf,
-                                      std::vector<unsigned> &Operands) {
+bool AbstractBytecodeParser::ParseInstruction(std::vector<unsigned> &Operands) {
+  BufPtr SaveAt = At;
   Operands.clear();
   unsigned iType = 0;
   unsigned Opcode = 0;
-  unsigned Op = read(Buf, EndBuf);
+  unsigned Op = read_uint();
 
   // bits   Instruction format:        Common to all formats
   // --------------------------
@@ -134,61 +221,56 @@ bool AbstractBytecodeParser::ParseInstruction(BufPtr& Buf, BufPtr EndBuf,
     Operands[2] = (Op >> 26) & 63;
     break;
   case 0:
-    Buf -= 4;  // Hrm, try this again...
-    Opcode = read_vbr_uint(Buf, EndBuf);
+    At -= 4;  // Hrm, try this again...
+    Opcode = read_vbr_uint();
     Opcode >>= 2;
-    iType = read_vbr_uint(Buf, EndBuf);
+    iType = read_vbr_uint();
 
-    unsigned NumOperands = read_vbr_uint(Buf, EndBuf);
+    unsigned NumOperands = read_vbr_uint();
     Operands.resize(NumOperands);
 
     if (NumOperands == 0)
       PARSE_ERROR("Zero-argument instruction found; this is invalid.");
 
     for (unsigned i = 0; i != NumOperands; ++i)
-      Operands[i] = read_vbr_uint(Buf, EndBuf);
-    align32(Buf, EndBuf);
+      Operands[i] = read_vbr_uint();
+    align32();
     break;
   }
 
-  return handler->handleInstruction(Opcode, getType(iType), Operands);
+  return handler->handleInstruction(Opcode, getType(iType), Operands, At-SaveAt);
 }
 
 /// ParseBasicBlock - In LLVM 1.0 bytecode files, we used to output one
 /// basicblock at a time.  This method reads in one of the basicblock packets.
-void AbstractBytecodeParser::ParseBasicBlock(BufPtr &Buf,
-                                            BufPtr EndBuf,
-                                            unsigned BlockNo) {
+void AbstractBytecodeParser::ParseBasicBlock( unsigned BlockNo) {
   handler->handleBasicBlockBegin( BlockNo );
 
   std::vector<unsigned> Args;
   bool is_terminating = false;
-  while (Buf < EndBuf)
-    is_terminating = ParseInstruction(Buf, EndBuf, Args);
+  while ( moreInBlock() )
+    is_terminating = ParseInstruction(Args);
 
   if ( ! is_terminating )
-    PARSE_ERROR(
-      "Failed to recognize instruction as terminating at end of block");
+    PARSE_ERROR("Non-terminated basic block found!");
 
   handler->handleBasicBlockEnd( BlockNo );
 }
 
-
 /// ParseInstructionList - Parse all of the BasicBlock's & Instruction's in the
 /// body of a function.  In post 1.0 bytecode files, we no longer emit basic
 /// block individually, in order to avoid per-basic-block overhead.
-unsigned AbstractBytecodeParser::ParseInstructionList( BufPtr &Buf, 
-                                                       BufPtr EndBuf) {
+unsigned AbstractBytecodeParser::ParseInstructionList() {
   unsigned BlockNo = 0;
   std::vector<unsigned> Args;
 
-  while (Buf < EndBuf) {
+  while ( moreInBlock() ) {
     handler->handleBasicBlockBegin( BlockNo );
 
     // Read instructions into this basic block until we get to a terminator
     bool is_terminating = false;
-    while (Buf < EndBuf && !is_terminating )
-	is_terminating = ParseInstruction(Buf, EndBuf, Args ) ;
+    while (moreInBlock() && !is_terminating )
+        is_terminating = ParseInstruction(Args ) ;
 
     if (!is_terminating)
       PARSE_ERROR( "Non-terminated basic block found!");
@@ -199,36 +281,34 @@ unsigned AbstractBytecodeParser::ParseInstructionList( BufPtr &Buf,
   return BlockNo;
 }
 
-void AbstractBytecodeParser::ParseSymbolTable(BufPtr &Buf, BufPtr EndBuf) {
+void AbstractBytecodeParser::ParseSymbolTable() {
   handler->handleSymbolTableBegin();
 
-  while (Buf < EndBuf) {
+  while ( moreInBlock() ) {
     // Symtab block header: [num entries][type id number]
-    unsigned NumEntries = read_vbr_uint(Buf, EndBuf);
-    unsigned Typ = read_vbr_uint(Buf, EndBuf);
+    unsigned NumEntries = read_vbr_uint();
+    unsigned Typ = read_vbr_uint();
     const Type *Ty = getType(Typ);
 
     handler->handleSymbolTablePlane( Typ, NumEntries, Ty );
 
     for (unsigned i = 0; i != NumEntries; ++i) {
       // Symtab entry: [def slot #][name]
-      unsigned slot = read_vbr_uint(Buf, EndBuf);
-      std::string Name = read_str(Buf, EndBuf);
+      unsigned slot = read_vbr_uint();
+      std::string Name = read_str();
 
       if (Typ == Type::TypeTyID)
         handler->handleSymbolTableType( i, slot, Name );
       else
-	handler->handleSymbolTableValue( i, slot, Name );
+        handler->handleSymbolTableValue( i, slot, Name );
     }
   }
-
-  if (Buf > EndBuf) 
-    PARSE_ERROR("Tried to read past end of buffer while reading symbol table.");
+  checkPastBlockEnd("Symbol Table");
 
   handler->handleSymbolTableEnd();
 }
 
-void AbstractBytecodeParser::ParseFunctionLazily(BufPtr &Buf, BufPtr EndBuf) {
+void AbstractBytecodeParser::ParseFunctionLazily() {
   if (FunctionSignatureList.empty())
     throw std::string("FunctionSignatureList empty!");
 
@@ -236,9 +316,10 @@ void AbstractBytecodeParser::ParseFunctionLazily(BufPtr &Buf, BufPtr EndBuf) {
   FunctionSignatureList.pop_back();
 
   // Save the information for future reading of the function
-  LazyFunctionLoadMap[FType] = LazyFunctionInfo(Buf, EndBuf);
+  LazyFunctionLoadMap[FType] = LazyFunctionInfo(BlockStart, BlockEnd);
+
   // Pretend we've `parsed' this function
-  Buf = EndBuf;
+  At = BlockEnd;
 }
 
 void AbstractBytecodeParser::ParseNextFunction(Type* FType) {
@@ -251,21 +332,20 @@ void AbstractBytecodeParser::ParseNextFunction(Type* FType) {
     return;
   }
 
-  BufPtr Buf = Fi->second.Buf;
-  BufPtr EndBuf = Fi->second.EndBuf;
+  BlockStart = At = Fi->second.Buf;
+  BlockEnd = Fi->second.Buf;
   assert(Fi->first == FType);
 
   LazyFunctionLoadMap.erase(Fi);
 
-  this->ParseFunctionBody( FType, Buf, EndBuf );
+  this->ParseFunctionBody( FType );
 }
 
-void AbstractBytecodeParser::ParseFunctionBody(const Type* FType, 
-                                               BufPtr &Buf, BufPtr EndBuf ) {
+void AbstractBytecodeParser::ParseFunctionBody(const Type* FType ) {
 
   GlobalValue::LinkageTypes Linkage = GlobalValue::ExternalLinkage;
 
-  unsigned LinkageType = read_vbr_uint(Buf, EndBuf);
+  unsigned LinkageType = read_vbr_uint();
   switch (LinkageType) {
   case 0: Linkage = GlobalValue::ExternalLinkage; break;
   case 1: Linkage = GlobalValue::WeakLinkage; break;
@@ -284,43 +364,45 @@ void AbstractBytecodeParser::ParseFunctionBody(const Type* FType,
   unsigned BlockNum = 0;
   bool InsertedArguments = false;
 
-  while (Buf < EndBuf) {
+  BufPtr MyEnd = BlockEnd;
+  while ( At < MyEnd ) {
     unsigned Type, Size;
-    BufPtr OldBuf = Buf;
-    readBlock(Buf, EndBuf, Type, Size);
+    BufPtr OldAt = At;
+    readBlock(Type, Size);
 
     switch (Type) {
     case BytecodeFormat::ConstantPool:
-      ParseConstantPool(Buf, Buf+Size, FunctionTypes );
+      ParseConstantPool(FunctionTypes );
       break;
 
     case BytecodeFormat::CompactionTable:
-      ParseCompactionTable(Buf, Buf+Size);
+      ParseCompactionTable();
       break;
 
     case BytecodeFormat::BasicBlock:
-      ParseBasicBlock(Buf, Buf+Size, BlockNum++);
+      ParseBasicBlock(BlockNum++);
       break;
 
     case BytecodeFormat::InstructionList:
       if (BlockNum) 
-	PARSE_ERROR("InstructionList must come before basic blocks!");
-      BlockNum = ParseInstructionList(Buf, Buf+Size);
+        PARSE_ERROR("InstructionList must come before basic blocks!");
+      BlockNum = ParseInstructionList();
       break;
 
     case BytecodeFormat::SymbolTable:
-      ParseSymbolTable(Buf, Buf+Size );
+      ParseSymbolTable();
       break;
 
     default:
-      Buf += Size;
-      if (OldBuf > Buf)
-	PARSE_ERROR("Wrapped around reading bytecode");
+      At += Size;
+      if (OldAt > At)
+        PARSE_ERROR("Wrapped around reading bytecode");
       break;
     }
+    BlockEnd = MyEnd;
 
     // Malformed bc file if read past end of block.
-    align32(Buf, EndBuf);
+    align32();
   }
 
   handler->handleFunctionEnd(FType);
@@ -336,21 +418,24 @@ void AbstractBytecodeParser::ParseAllFunctionBodies() {
 
   while ( Fi != Fe ) {
     const Type* FType = Fi->first;
-    this->ParseFunctionBody(FType, Fi->second.Buf, Fi->second.EndBuf);
+    BlockStart = At = Fi->second.Buf;
+    BlockEnd = Fi->second.EndBuf;
+    this->ParseFunctionBody(FType);
+    ++Fi;
   }
 }
 
-void AbstractBytecodeParser::ParseCompactionTable(BufPtr &Buf, BufPtr End) {
+void AbstractBytecodeParser::ParseCompactionTable() {
 
   handler->handleCompactionTableBegin();
 
-  while (Buf != End) {
-    unsigned NumEntries = read_vbr_uint(Buf, End);
+  while ( moreInBlock() ) {
+    unsigned NumEntries = read_vbr_uint();
     unsigned Ty;
 
     if ((NumEntries & 3) == 3) {
       NumEntries >>= 2;
-      Ty = read_vbr_uint(Buf, End);
+      Ty = read_vbr_uint();
     } else {
       Ty = NumEntries >> 2;
       NumEntries &= 3;
@@ -360,25 +445,24 @@ void AbstractBytecodeParser::ParseCompactionTable(BufPtr &Buf, BufPtr End) {
 
     if (Ty == Type::TypeTyID) {
       for (unsigned i = 0; i != NumEntries; ++i) {
-	unsigned TypeSlot = read_vbr_uint(Buf,End);
+        unsigned TypeSlot = read_vbr_uint();
         const Type *Typ = getGlobalTableType(TypeSlot);
-	handler->handleCompactionTableType( i, TypeSlot, Typ );
+        handler->handleCompactionTableType( i, TypeSlot, Typ );
       }
     } else {
       const Type *Typ = getType(Ty);
       // Push the implicit zero
       for (unsigned i = 0; i != NumEntries; ++i) {
-	unsigned ValSlot = read_vbr_uint(Buf, End);
-	handler->handleCompactionTableValue( i, ValSlot, Typ );
+        unsigned ValSlot = read_vbr_uint();
+        handler->handleCompactionTableValue( i, ValSlot, Typ );
       }
     }
   }
   handler->handleCompactionTableEnd();
 }
 
-const Type *AbstractBytecodeParser::ParseTypeConstant(const unsigned char *&Buf,
-					      const unsigned char *EndBuf) {
-  unsigned PrimType = read_vbr_uint(Buf, EndBuf);
+const Type *AbstractBytecodeParser::ParseTypeConstant() {
+  unsigned PrimType = read_vbr_uint();
 
   const Type *Val = 0;
   if ((Val = Type::getPrimitiveType((Type::PrimitiveID)PrimType)))
@@ -386,13 +470,13 @@ const Type *AbstractBytecodeParser::ParseTypeConstant(const unsigned char *&Buf,
   
   switch (PrimType) {
   case Type::FunctionTyID: {
-    const Type *RetType = getType(read_vbr_uint(Buf, EndBuf));
+    const Type *RetType = getType(read_vbr_uint());
 
-    unsigned NumParams = read_vbr_uint(Buf, EndBuf);
+    unsigned NumParams = read_vbr_uint();
 
     std::vector<const Type*> Params;
     while (NumParams--)
-      Params.push_back(getType(read_vbr_uint(Buf, EndBuf)));
+      Params.push_back(getType(read_vbr_uint()));
 
     bool isVarArg = Params.size() && Params.back() == Type::VoidTy;
     if (isVarArg) Params.pop_back();
@@ -402,10 +486,10 @@ const Type *AbstractBytecodeParser::ParseTypeConstant(const unsigned char *&Buf,
     return result;
   }
   case Type::ArrayTyID: {
-    unsigned ElTyp = read_vbr_uint(Buf, EndBuf);
+    unsigned ElTyp = read_vbr_uint();
     const Type *ElementType = getType(ElTyp);
 
-    unsigned NumElements = read_vbr_uint(Buf, EndBuf);
+    unsigned NumElements = read_vbr_uint();
 
     BCR_TRACE(5, "Array Type Constant #" << ElTyp << " size=" 
               << NumElements << "\n");
@@ -415,10 +499,10 @@ const Type *AbstractBytecodeParser::ParseTypeConstant(const unsigned char *&Buf,
   }
   case Type::StructTyID: {
     std::vector<const Type*> Elements;
-    unsigned Typ = read_vbr_uint(Buf, EndBuf);
+    unsigned Typ = read_vbr_uint();
     while (Typ) {         // List is terminated by void/0 typeid
       Elements.push_back(getType(Typ));
-      Typ = read_vbr_uint(Buf, EndBuf);
+      Typ = read_vbr_uint();
     }
 
     Type* result = StructType::get(Elements);
@@ -426,7 +510,7 @@ const Type *AbstractBytecodeParser::ParseTypeConstant(const unsigned char *&Buf,
     return result;
   }
   case Type::PointerTyID: {
-    unsigned ElTyp = read_vbr_uint(Buf, EndBuf);
+    unsigned ElTyp = read_vbr_uint();
     BCR_TRACE(5, "Pointer Type Constant #" << ElTyp << "\n");
     Type* result = PointerType::get(getType(ElTyp));
     handler->handleType( result );
@@ -455,10 +539,9 @@ const Type *AbstractBytecodeParser::ParseTypeConstant(const unsigned char *&Buf,
 // something and when we reread the type later, we can replace the opaque type
 // with a new resolved concrete type.
 //
-void AbstractBytecodeParser::ParseTypeConstants(const unsigned char *&Buf,
-                                        const unsigned char *EndBuf,
-					TypeListTy &Tab,
-					unsigned NumEntries) {
+void AbstractBytecodeParser::ParseTypeConstants( 
+  TypeListTy &Tab, unsigned NumEntries
+) {
   assert(Tab.size() == 0 && "should not have read type constants in before!");
 
   // Insert a bunch of opaque types to be resolved later...
@@ -470,7 +553,7 @@ void AbstractBytecodeParser::ParseTypeConstants(const unsigned char *&Buf,
   // opaque types just inserted.
   //
   for (unsigned i = 0; i != NumEntries; ++i) {
-    const Type *NewTy = ParseTypeConstant(Buf, EndBuf), *OldTy = Tab[i].get();
+    const Type *NewTy = ParseTypeConstant(), *OldTy = Tab[i].get();
     if (NewTy == 0) throw std::string("Couldn't parse type!");
     BCR_TRACE(4, "#" << i << ": Read Type Constant: '" << NewTy <<
               "' Replacing: " << OldTy << "\n");
@@ -497,18 +580,16 @@ void AbstractBytecodeParser::ParseTypeConstants(const unsigned char *&Buf,
 }
 
 
-void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
-                                             const unsigned char *EndBuf,
-                                             unsigned TypeID) {
+void AbstractBytecodeParser::ParseConstantValue(unsigned TypeID) {
 
   // We must check for a ConstantExpr before switching by type because
   // a ConstantExpr can be of any type, and has no explicit value.
   // 
   // 0 if not expr; numArgs if is expr
-  unsigned isExprNumArgs = read_vbr_uint(Buf, EndBuf);
+  unsigned isExprNumArgs = read_vbr_uint();
   
   if (isExprNumArgs) {
-    unsigned Opcode = read_vbr_uint(Buf, EndBuf);
+    unsigned Opcode = read_vbr_uint();
     const Type* Typ = getType(TypeID);
     
     // FIXME: Encoding of constant exprs could be much more compact!
@@ -517,8 +598,8 @@ void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
 
     // Read the slot number and types of each of the arguments
     for (unsigned i = 0; i != isExprNumArgs; ++i) {
-      unsigned ArgValSlot = read_vbr_uint(Buf, EndBuf);
-      unsigned ArgTypeSlot = read_vbr_uint(Buf, EndBuf);
+      unsigned ArgValSlot = read_vbr_uint();
+      unsigned ArgTypeSlot = read_vbr_uint();
       BCR_TRACE(4, "CE Arg " << i << ": Type: '" << *getType(ArgTypeSlot)
                 << "'  slot: " << ArgValSlot << "\n");
       
@@ -534,7 +615,7 @@ void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
   const Type *Ty = getType(TypeID);
   switch (Ty->getPrimitiveID()) {
   case Type::BoolTyID: {
-    unsigned Val = read_vbr_uint(Buf, EndBuf);
+    unsigned Val = read_vbr_uint();
     if (Val != 0 && Val != 1) 
       PARSE_ERROR("Invalid boolean value read.");
 
@@ -545,7 +626,7 @@ void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
   case Type::UByteTyID:   // Unsigned integer types...
   case Type::UShortTyID:
   case Type::UIntTyID: {
-    unsigned Val = read_vbr_uint(Buf, EndBuf);
+    unsigned Val = read_vbr_uint();
     if (!ConstantUInt::isValueValidForType(Ty, Val)) 
       throw std::string("Invalid unsigned byte/short/int read.");
     handler->handleConstantValue( ConstantUInt::get(Ty, Val) );
@@ -553,7 +634,7 @@ void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
   }
 
   case Type::ULongTyID: {
-    handler->handleConstantValue( ConstantUInt::get(Ty, read_vbr_uint64(Buf, EndBuf)) );
+    handler->handleConstantValue( ConstantUInt::get(Ty, read_vbr_uint64()) );
     break;
   }
 
@@ -561,7 +642,7 @@ void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
   case Type::ShortTyID:
   case Type::IntTyID: {
   case Type::LongTyID:
-    int64_t Val = read_vbr_int64(Buf, EndBuf);
+    int64_t Val = read_vbr_int64();
     if (!ConstantSInt::isValueValidForType(Ty, Val)) 
       throw std::string("Invalid signed byte/short/int/long read.");
     handler->handleConstantValue(  ConstantSInt::get(Ty, Val) );
@@ -570,14 +651,14 @@ void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
 
   case Type::FloatTyID: {
     float F;
-    input_data(Buf, EndBuf, &F, &F+1);
+    read_data(&F, &F+1);
     handler->handleConstantValue( ConstantFP::get(Ty, F) );
     break;
   }
 
   case Type::DoubleTyID: {
     double Val;
-    input_data(Buf, EndBuf, &Val, &Val+1);
+    read_data(&Val, &Val+1);
     handler->handleConstantValue( ConstantFP::get(Ty, Val) );
     break;
   }
@@ -592,7 +673,7 @@ void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
     std::vector<unsigned> Elements;
     Elements.reserve(NumElements);
     while (NumElements--)     // Read all of the elements of the constant.
-      Elements.push_back(read_vbr_uint(Buf, EndBuf));
+      Elements.push_back(read_vbr_uint());
 
     handler->handleConstantArray( AT, Elements );
     break;
@@ -603,15 +684,16 @@ void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
     std::vector<unsigned> Elements;
     Elements.reserve(ST->getNumElements());
     for (unsigned i = 0; i != ST->getNumElements(); ++i)
-      Elements.push_back(read_vbr_uint(Buf, EndBuf));
-
+      Elements.push_back(read_vbr_uint());
     handler->handleConstantStruct( ST, Elements );
+    break;
   }    
 
   case Type::PointerTyID: {  // ConstantPointerRef value...
     const PointerType *PT = cast<PointerType>(Ty);
-    unsigned Slot = read_vbr_uint(Buf, EndBuf);
+    unsigned Slot = read_vbr_uint();
     handler->handleConstantPointer( PT, Slot );
+    break;
   }
 
   default:
@@ -620,16 +702,13 @@ void AbstractBytecodeParser::ParseConstantValue(const unsigned char *&Buf,
   }
 }
 
-void AbstractBytecodeParser::ParseGlobalTypes(const unsigned char *&Buf,
-                                      const unsigned char *EndBuf) {
-  ParseConstantPool(Buf, EndBuf, ModuleTypes);
+void AbstractBytecodeParser::ParseGlobalTypes() {
+  ParseConstantPool(ModuleTypes);
 }
 
-void AbstractBytecodeParser::ParseStringConstants(const unsigned char *&Buf,
-                                          const unsigned char *EndBuf,
-                                          unsigned NumEntries ){
+void AbstractBytecodeParser::ParseStringConstants(unsigned NumEntries ){
   for (; NumEntries; --NumEntries) {
-    unsigned Typ = read_vbr_uint(Buf, EndBuf);
+    unsigned Typ = read_vbr_uint();
     const Type *Ty = getType(Typ);
     if (!isa<ArrayType>(Ty))
       throw std::string("String constant data invalid!");
@@ -641,7 +720,7 @@ void AbstractBytecodeParser::ParseStringConstants(const unsigned char *&Buf,
     
     // Read character data.  The type tells us how long the string is.
     char Data[ATy->getNumElements()];
-    input_data(Buf, EndBuf, Data, Data+ATy->getNumElements());
+    read_data(Data, Data+ATy->getNumElements());
 
     std::vector<Constant*> Elements(ATy->getNumElements());
     if (ATy->getElementType() == Type::SByteTy)
@@ -658,35 +737,33 @@ void AbstractBytecodeParser::ParseStringConstants(const unsigned char *&Buf,
 }
 
 
-void AbstractBytecodeParser::ParseConstantPool(const unsigned char *&Buf,
-                                       const unsigned char *EndBuf,
-                                       TypeListTy &TypeTab) {
-  while (Buf < EndBuf) {
-    unsigned NumEntries = read_vbr_uint(Buf, EndBuf);
-    unsigned Typ = read_vbr_uint(Buf, EndBuf);
+void AbstractBytecodeParser::ParseConstantPool( TypeListTy &TypeTab) {
+  while ( moreInBlock() ) {
+    unsigned NumEntries = read_vbr_uint();
+    unsigned Typ = read_vbr_uint();
     if (Typ == Type::TypeTyID) {
-      ParseTypeConstants(Buf, EndBuf, TypeTab, NumEntries);
+      ParseTypeConstants(TypeTab, NumEntries);
     } else if (Typ == Type::VoidTyID) {
-      ParseStringConstants(Buf, EndBuf, NumEntries);
+      ParseStringConstants(NumEntries);
     } else {
       BCR_TRACE(3, "Type: '" << *getType(Typ) << "'  NumEntries: "
                 << NumEntries << "\n");
 
       for (unsigned i = 0; i < NumEntries; ++i) {
-        ParseConstantValue(Buf, EndBuf, Typ);
+        ParseConstantValue(Typ);
       }
     }
   }
   
-  if (Buf > EndBuf) PARSE_ERROR("Read past end of buffer.");
+  checkPastBlockEnd("Constant Pool");
 }
 
-void AbstractBytecodeParser::ParseModuleGlobalInfo(BufPtr &Buf, BufPtr End) {
+void AbstractBytecodeParser::ParseModuleGlobalInfo() {
 
   handler->handleModuleGlobalsBegin();
 
   // Read global variables...
-  unsigned VarType = read_vbr_uint(Buf, End);
+  unsigned VarType = read_vbr_uint();
   while (VarType != Type::VoidTyID) { // List is terminated by Void
     // VarType Fields: bit0 = isConstant, bit1 = hasInitializer, bit2,3,4 =
     // Linkage, bit4+ = slot#
@@ -721,17 +798,17 @@ void AbstractBytecodeParser::ParseModuleGlobalInfo(BufPtr &Buf, BufPtr End) {
 
     // Create the global variable...
     if (hasInitializer) {
-      unsigned initSlot = read_vbr_uint(Buf,End);
+      unsigned initSlot = read_vbr_uint();
       handler->handleInitializedGV( ElTy, isConstant, Linkage, initSlot );
     } else 
       handler->handleGlobalVariable( ElTy, isConstant, Linkage );
 
     // Get next item
-    VarType = read_vbr_uint(Buf, End);
+    VarType = read_vbr_uint();
   }
 
   // Read the function objects for all of the functions that are coming
-  unsigned FnSignature = read_vbr_uint(Buf, End);
+  unsigned FnSignature = read_vbr_uint();
   while (FnSignature != Type::VoidTyID) { // List is terminated by Void
     const Type *Ty = getType(FnSignature);
     if (!isa<PointerType>(Ty) ||
@@ -750,22 +827,26 @@ void AbstractBytecodeParser::ParseModuleGlobalInfo(BufPtr &Buf, BufPtr End) {
     handler->handleFunctionDeclaration(Ty);
 
     // Get Next function signature
-    FnSignature = read_vbr_uint(Buf, End);
+    FnSignature = read_vbr_uint();
   }
 
   if (hasInconsistentModuleGlobalInfo)
-    align32(Buf, End);
+    align32();
+
+  // Now that the function signature list is set up, reverse it so that we can 
+  // remove elements efficiently from the back of the vector.
+  std::reverse(FunctionSignatureList.begin(), FunctionSignatureList.end());
 
   // This is for future proofing... in the future extra fields may be added that
   // we don't understand, so we transparently ignore them.
   //
-  Buf = End;
+  At = BlockEnd;
 
   handler->handleModuleGlobalsEnd();
 }
 
-void AbstractBytecodeParser::ParseVersionInfo(BufPtr &Buf, BufPtr EndBuf) {
-  unsigned Version = read_vbr_uint(Buf, EndBuf);
+void AbstractBytecodeParser::ParseVersionInfo() {
+  unsigned Version = read_vbr_uint();
 
   // Unpack version number: low four bits are for flags, top bits = version
   Module::Endianness  Endianness;
@@ -814,85 +895,164 @@ void AbstractBytecodeParser::ParseVersionInfo(BufPtr &Buf, BufPtr EndBuf) {
   handler->handleVersionInfo(RevisionNum, Endianness, PointerSize );
 }
 
-void AbstractBytecodeParser::ParseModule(BufPtr &Buf, BufPtr EndBuf ) {
+void AbstractBytecodeParser::ParseModule() {
   unsigned Type, Size;
-  readBlock(Buf, EndBuf, Type, Size);
-  if (Type != BytecodeFormat::Module || Buf+Size != EndBuf)
-    // Hrm, not a class?
-    PARSE_ERROR("Expected Module block! B: " << unsigned(intptr_t(Buf)) <<
-        ", S: " << Size << " E: " << unsigned(intptr_t(EndBuf))); 
+
+  FunctionSignatureList.clear(); // Just in case...
 
   // Read into instance variables...
-  ParseVersionInfo(Buf, EndBuf);
-  align32(Buf, EndBuf);
+  ParseVersionInfo();
+  align32(); /// FIXME: Is this redundant? VI is first and 4 bytes!
 
   bool SeenModuleGlobalInfo = false;
   bool SeenGlobalTypePlane = false;
-  while (Buf < EndBuf) {
-    BufPtr OldBuf = Buf;
-    readBlock(Buf, EndBuf, Type, Size);
+  BufPtr MyEnd = BlockEnd;
+  while (At < MyEnd) {
+    BufPtr OldAt = At;
+    readBlock(Type, Size);
 
     switch (Type) {
 
     case BytecodeFormat::GlobalTypePlane:
       if ( SeenGlobalTypePlane )
-	PARSE_ERROR("Two GlobalTypePlane Blocks Encountered!");
+        PARSE_ERROR("Two GlobalTypePlane Blocks Encountered!");
 
-      ParseGlobalTypes(Buf, Buf+Size);
+      ParseGlobalTypes();
       SeenGlobalTypePlane = true;
       break;
 
     case BytecodeFormat::ModuleGlobalInfo: 
       if ( SeenModuleGlobalInfo )
-	PARSE_ERROR("Two ModuleGlobalInfo Blocks Encountered!");
-      ParseModuleGlobalInfo(Buf, Buf+Size);
+        PARSE_ERROR("Two ModuleGlobalInfo Blocks Encountered!");
+      ParseModuleGlobalInfo();
       SeenModuleGlobalInfo = true;
       break;
 
     case BytecodeFormat::ConstantPool:
-      ParseConstantPool(Buf, Buf+Size, ModuleTypes);
+      ParseConstantPool(ModuleTypes);
       break;
 
     case BytecodeFormat::Function:
-      ParseFunctionLazily(Buf, Buf+Size);
+      ParseFunctionLazily();
       break;
 
     case BytecodeFormat::SymbolTable:
-      ParseSymbolTable(Buf, Buf+Size );
+      ParseSymbolTable();
       break;
 
     default:
-      Buf += Size;
-      if (OldBuf > Buf) 
-      {
-	PARSE_ERROR("Unexpected Block of Type" << Type << "encountered!" );
+      At += Size;
+      if (OldAt > At) {
+        PARSE_ERROR("Unexpected Block of Type" << Type << "encountered!" );
       }
       break;
     }
-    align32(Buf, EndBuf);
+    BlockEnd = MyEnd;
+    align32();
   }
+
+  /// Make sure we pulled them all out. If we didn't then there's a declaration
+  /// but a missing body. That's not allowed.
+  if (!FunctionSignatureList.empty())
+    throw std::string(
+      "Function declared, but bytecode stream ended before definition");
 }
 
 void AbstractBytecodeParser::ParseBytecode(
-       BufPtr Buf, unsigned Length,
+       BufPtr b, unsigned Length,
        const std::string &ModuleID) {
 
+  At = MemStart = BlockStart = b;
+  MemEnd = BlockEnd = b + Length;
   handler->handleStart();
-  unsigned char *EndBuf = (unsigned char*)(Buf + Length);
 
   // Read and check signature...
-  unsigned Sig = read(Buf, EndBuf);
+  unsigned Sig = read_uint();
   if (Sig != ('l' | ('l' << 8) | ('v' << 16) | ('m' << 24))) {
     PARSE_ERROR("Invalid bytecode signature: " << Sig);
   }
 
   handler->handleModuleBegin(ModuleID);
 
-  this->ParseModule(Buf, EndBuf);
+  unsigned Type, Size;
+  readBlock(Type, Size);
+  if ( Type != BytecodeFormat::Module ) {
+    PARSE_ERROR("Expected Module Block! At: " << unsigned(intptr_t(At))
+      << ", Type:" << Type << ", Size:" << Size);
+  }
+  if ( At + Size != MemEnd ) {
+    PARSE_ERROR("Invalid Top Level Block Length! At: " 
+      << unsigned(intptr_t(At)) << ", Type:" << Type << ", Size:" << Size);
+  }
+  this->ParseModule();
 
   handler->handleModuleEnd(ModuleID);
 
   handler->handleFinish();
 }
 
+//===----------------------------------------------------------------------===//
+//=== Default Implementations of Handler Methods
+//===----------------------------------------------------------------------===//
+
+bool BytecodeHandler::handleError(const std::string& str ) { return false; }
+void BytecodeHandler::handleStart() { }
+void BytecodeHandler::handleFinish() { }
+void BytecodeHandler::handleModuleBegin(const std::string& id) { }
+void BytecodeHandler::handleModuleEnd(const std::string& id) { }
+void BytecodeHandler::handleVersionInfo( unsigned char RevisionNum,
+  Module::Endianness Endianness, Module::PointerSize PointerSize) { }
+void BytecodeHandler::handleModuleGlobalsBegin() { }
+void BytecodeHandler::handleGlobalVariable( 
+  const Type* ElemType, bool isConstant, GlobalValue::LinkageTypes ) { }
+void BytecodeHandler::handleInitializedGV( 
+  const Type* ElemType, bool isConstant, GlobalValue::LinkageTypes,
+  unsigned initSlot) {}
+void BytecodeHandler::handleType( const Type* Ty ) {}
+void BytecodeHandler::handleFunctionDeclaration( 
+  const Type* FuncType) {}
+void BytecodeHandler::handleModuleGlobalsEnd() { } 
+void BytecodeHandler::handleCompactionTableBegin() { } 
+void BytecodeHandler::handleCompactionTablePlane( unsigned Ty, 
+  unsigned NumEntries) {}
+void BytecodeHandler::handleCompactionTableType( unsigned i, unsigned TypSlot, 
+  const Type* ) {}
+void BytecodeHandler::handleCompactionTableValue( unsigned i, unsigned ValSlot,
+  const Type* ) {}
+void BytecodeHandler::handleCompactionTableEnd() { }
+void BytecodeHandler::handleSymbolTableBegin() { }
+void BytecodeHandler::handleSymbolTablePlane( unsigned Ty, unsigned NumEntries, 
+  const Type* Typ) { }
+void BytecodeHandler::handleSymbolTableType( unsigned i, unsigned slot, 
+  const std::string& name ) { }
+void BytecodeHandler::handleSymbolTableValue( unsigned i, unsigned slot, 
+  const std::string& name ) { }
+void BytecodeHandler::handleSymbolTableEnd() { }