diff --git a/llvm/lib/Bytecode/Reader/InstructionReader.cpp b/llvm/lib/Bytecode/Reader/InstructionReader.cpp
index 0ab2655..f334085 100644
--- a/llvm/lib/Bytecode/Reader/InstructionReader.cpp
+++ b/llvm/lib/Bytecode/Reader/InstructionReader.cpp
@@ -17,30 +17,32 @@
 #include "llvm/iPHINode.h"
 #include "llvm/iOther.h"
 
-bool BytecodeParser::ParseRawInst(const unsigned char *&Buf,
-                                  const unsigned char *EndBuf, 
-				  RawInst &Result) {
+std::auto_ptr<RawInst>
+BytecodeParser::ParseRawInst(const unsigned char *&Buf,
+                             const unsigned char *EndBuf) { 
   unsigned Op, Typ;
-  if (read(Buf, EndBuf, Op)) return true;
+  std::auto_ptr<RawInst> Result = std::auto_ptr<RawInst>(new RawInst());
+  if (read(Buf, EndBuf, Op)) 
+    throw std::string("Error reading from buffer.");
 
   // bits   Instruction format:        Common to all formats
   // --------------------------
   // 01-00: Opcode type, fixed to 1.
   // 07-02: Opcode
-  Result.NumOperands = (Op >> 0) & 03;
-  Result.Opcode      = (Op >> 2) & 63;
+  Result->NumOperands = (Op >> 0) & 03;
+  Result->Opcode      = (Op >> 2) & 63;
 
-  switch (Result.NumOperands) {
+  switch (Result->NumOperands) {
   case 1:
     // bits   Instruction format:
     // --------------------------
     // 19-08: Resulting type plane
     // 31-20: Operand #1 (if set to (2^12-1), then zero operands)
     //
-    Result.Ty   = getType((Op >> 8) & 4095);
-    Result.Arg1 = (Op >> 20) & 4095;
-    if (Result.Arg1 == 4095)    // Handle special encoding for 0 operands...
-      Result.NumOperands = 0;
+    Result->Ty   = getType((Op >> 8) & 4095);
+    Result->Arg1 = (Op >> 20) & 4095;
+    if (Result->Arg1 == 4095)    // Handle special encoding for 0 operands...
+      Result->NumOperands = 0;
     break;
   case 2:
     // bits   Instruction format:
@@ -49,9 +51,9 @@
     // 23-16: Operand #1
     // 31-24: Operand #2  
     //
-    Result.Ty   = getType((Op >> 8) & 255);
-    Result.Arg1 = (Op >> 16) & 255;
-    Result.Arg2 = (Op >> 24) & 255;
+    Result->Ty   = getType((Op >> 8) & 255);
+    Result->Arg1 = (Op >> 16) & 255;
+    Result->Arg2 = (Op >> 24) & 255;
     break;
   case 3:
     // bits   Instruction format:
@@ -61,112 +63,121 @@
     // 25-20: Operand #2
     // 31-26: Operand #3
     //
-    Result.Ty   = getType((Op >> 8) & 63);
-    Result.Arg1 = (Op >> 14) & 63;
-    Result.Arg2 = (Op >> 20) & 63;
-    Result.Arg3 = (Op >> 26) & 63;
+    Result->Ty   = getType((Op >> 8) & 63);
+    Result->Arg1 = (Op >> 14) & 63;
+    Result->Arg2 = (Op >> 20) & 63;
+    Result->Arg3 = (Op >> 26) & 63;
     break;
   case 0:
     Buf -= 4;  // Hrm, try this again...
-    if (read_vbr(Buf, EndBuf, Result.Opcode)) return true;
-    Result.Opcode >>= 2;
-    if (read_vbr(Buf, EndBuf, Typ)) return true;
-    Result.Ty = getType(Typ);
-    if (Result.Ty == 0) return true;
-    if (read_vbr(Buf, EndBuf, Result.NumOperands)) return true;
+    if (read_vbr(Buf, EndBuf, Result->Opcode))
+      throw std::string("Error reading from buffer.");
+    Result->Opcode >>= 2;
+    if (read_vbr(Buf, EndBuf, Typ))
+      throw std::string("Error reading from buffer.");
+    Result->Ty = getType(Typ);
+    if (Result->Ty == 0) 
+      throw std::string("Invalid type read in instruction.");
+    if (read_vbr(Buf, EndBuf, Result->NumOperands))
+      throw std::string("Error reading from buffer.");
 
-    switch (Result.NumOperands) {
+    switch (Result->NumOperands) {
     case 0: 
-      std::cerr << "Zero Arg instr found!\n"; 
-      return true;  // This encoding is invalid!
+      throw std::string("Zero-argument instruction found; this is invalid.");
     case 1: 
-      if (read_vbr(Buf, EndBuf, Result.Arg1)) return true;
+      if (read_vbr(Buf, EndBuf, Result->Arg1)) 
+        throw std::string("Error reading from buffer");
       break;
     case 2:
-      if (read_vbr(Buf, EndBuf, Result.Arg1) || 
-	  read_vbr(Buf, EndBuf, Result.Arg2)) return true;
+      if (read_vbr(Buf, EndBuf, Result->Arg1) || 
+	  read_vbr(Buf, EndBuf, Result->Arg2))
+        throw std::string("Error reading from buffer");
       break;
     case 3:
-      if (read_vbr(Buf, EndBuf, Result.Arg1) || 
-	  read_vbr(Buf, EndBuf, Result.Arg2) ||
-          read_vbr(Buf, EndBuf, Result.Arg3)) return true;
+      if (read_vbr(Buf, EndBuf, Result->Arg1) || 
+	  read_vbr(Buf, EndBuf, Result->Arg2) ||
+          read_vbr(Buf, EndBuf, Result->Arg3))
+        throw std::string("Error reading from buffer");
       break;
     default:
-      if (read_vbr(Buf, EndBuf, Result.Arg1) || 
-	  read_vbr(Buf, EndBuf, Result.Arg2)) return true;
+      if (read_vbr(Buf, EndBuf, Result->Arg1) || 
+	  read_vbr(Buf, EndBuf, Result->Arg2))
+        throw std::string("Error reading from buffer");
 
       // Allocate a vector to hold arguments 3, 4, 5, 6 ...
-      Result.VarArgs = new std::vector<unsigned>(Result.NumOperands-2);
-      for (unsigned a = 0; a < Result.NumOperands-2; a++)
-	if (read_vbr(Buf, EndBuf, (*Result.VarArgs)[a])) return true;
+      Result->VarArgs = new std::vector<unsigned>(Result->NumOperands-2);
+      for (unsigned a = 0; a < Result->NumOperands-2; a++)
+	if (read_vbr(Buf, EndBuf, (*Result->VarArgs)[a]))
+        throw std::string("Error reading from buffer");          
+
       break;
     }
-    if (align32(Buf, EndBuf)) return true;
+    if (align32(Buf, EndBuf)) 
+      throw std::string("Unaligned bytecode buffer.");
     break;
   }
 
 #if 0
-  std::cerr << "NO: "  << Result.NumOperands   << " opcode: " << Result.Opcode 
-            << " Ty: " << Result.Ty->getDescription() << " arg1: "<< Result.Arg1
-            << " arg2: "   << Result.Arg2 << " arg3: "   << Result.Arg3 << "\n";
+  std::cerr << "NO: "  << Result->NumOperands << " opcode: " << Result->Opcode 
+            << " Ty: "<< Result->Ty->getDescription()<< " arg1: "<< Result->Arg1
+            << " arg2: " << Result->Arg2 << " arg3: "   << Result->Arg3 << "\n";
 #endif
-  return false;
+  return Result;
 }
 
 
 bool BytecodeParser::ParseInstruction(const unsigned char *&Buf,
                                       const unsigned char *EndBuf,
 				      Instruction *&Res) {
-  RawInst Raw;
-  if (ParseRawInst(Buf, EndBuf, Raw))
-    return true;
+  std::auto_ptr<RawInst> Raw = ParseRawInst(Buf, EndBuf);
 
-  if (Raw.Opcode >= Instruction::BinaryOpsBegin &&
-      Raw.Opcode <  Instruction::BinaryOpsEnd  && Raw.NumOperands == 2) {
-    Res = BinaryOperator::create((Instruction::BinaryOps)Raw.Opcode,
-				 getValue(Raw.Ty, Raw.Arg1),
-				 getValue(Raw.Ty, Raw.Arg2));
+  if (Raw->Opcode >= Instruction::BinaryOpsBegin &&
+      Raw->Opcode <  Instruction::BinaryOpsEnd  && Raw->NumOperands == 2) {
+    Res = BinaryOperator::create((Instruction::BinaryOps)Raw->Opcode,
+				 getValue(Raw->Ty, Raw->Arg1),
+				 getValue(Raw->Ty, Raw->Arg2));
     return false;
-  } 
+  }
 
   Value *V;
-  switch (Raw.Opcode) {
+  switch (Raw->Opcode) {
   case Instruction::VarArg:
   case Instruction::Cast: {
-    V = getValue(Raw.Ty, Raw.Arg1);
-    const Type *Ty = getType(Raw.Arg2);
+    V = getValue(Raw->Ty, Raw->Arg1);
+    const Type *Ty = getType(Raw->Arg2);
     if (V == 0 || Ty == 0) { std::cerr << "Invalid cast!\n"; return true; }
-    if (Raw.Opcode == Instruction::Cast)
+    if (Raw->Opcode == Instruction::Cast)
       Res = new CastInst(V, Ty);
     else
       Res = new VarArgInst(V, Ty);
     return false;
   }
   case Instruction::PHINode: {
-    PHINode *PN = new PHINode(Raw.Ty);
-    switch (Raw.NumOperands) {
+    PHINode *PN = new PHINode(Raw->Ty);
+    switch (Raw->NumOperands) {
     case 0: 
     case 1: 
     case 3: std::cerr << "Invalid phi node encountered!\n"; 
             delete PN; 
 	    return true;
-    case 2: PN->addIncoming(getValue(Raw.Ty, Raw.Arg1),
-			    cast<BasicBlock>(getValue(Type::LabelTy,Raw.Arg2)));
+    case 2: PN->addIncoming(getValue(Raw->Ty, Raw->Arg1),
+			    cast<BasicBlock>(getValue(Type::LabelTy,
+                                                      Raw->Arg2)));
       break;
     default:
-      PN->addIncoming(getValue(Raw.Ty, Raw.Arg1), 
-		      cast<BasicBlock>(getValue(Type::LabelTy, Raw.Arg2)));
-      if (Raw.VarArgs->size() & 1) {
+      PN->addIncoming(getValue(Raw->Ty, Raw->Arg1), 
+		      cast<BasicBlock>(getValue(Type::LabelTy, Raw->Arg2)));
+      if (Raw->VarArgs->size() & 1) {
 	std::cerr << "PHI Node with ODD number of arguments!\n";
 	delete PN;
 	return true;
       } else {
-        std::vector<unsigned> &args = *Raw.VarArgs;
+        std::vector<unsigned> &args = *Raw->VarArgs;
         for (unsigned i = 0; i < args.size(); i+=2)
-          PN->addIncoming(getValue(Raw.Ty, args[i]),
+          PN->addIncoming(getValue(Raw->Ty, args[i]),
 			  cast<BasicBlock>(getValue(Type::LabelTy, args[i+1])));
       }
-      delete Raw.VarArgs; 
+      delete Raw->VarArgs; 
       break;
     }
     Res = PN;
@@ -175,54 +186,54 @@
 
   case Instruction::Shl:
   case Instruction::Shr:
-    Res = new ShiftInst((Instruction::OtherOps)Raw.Opcode,
-			getValue(Raw.Ty, Raw.Arg1),
-			getValue(Type::UByteTy, Raw.Arg2));
+    Res = new ShiftInst((Instruction::OtherOps)Raw->Opcode,
+			getValue(Raw->Ty, Raw->Arg1),
+			getValue(Type::UByteTy, Raw->Arg2));
     return false;
   case Instruction::Ret:
-    if (Raw.NumOperands == 0) {
+    if (Raw->NumOperands == 0) {
       Res = new ReturnInst(); return false; 
-    } else if (Raw.NumOperands == 1) {
-      Res = new ReturnInst(getValue(Raw.Ty, Raw.Arg1)); return false; 
+    } else if (Raw->NumOperands == 1) {
+      Res = new ReturnInst(getValue(Raw->Ty, Raw->Arg1)); return false; 
     }
     break;
 
   case Instruction::Br:
-    if (Raw.NumOperands == 1) {
-      Res = new BranchInst(cast<BasicBlock>(getValue(Type::LabelTy, Raw.Arg1)));
+    if (Raw->NumOperands == 1) {
+      Res = new BranchInst(cast<BasicBlock>(getValue(Type::LabelTy,Raw->Arg1)));
       return false;
-    } else if (Raw.NumOperands == 3) {
-      Res = new BranchInst(cast<BasicBlock>(getValue(Type::LabelTy, Raw.Arg1)),
-			   cast<BasicBlock>(getValue(Type::LabelTy, Raw.Arg2)),
-                                            getValue(Type::BoolTy , Raw.Arg3));
+    } else if (Raw->NumOperands == 3) {
+      Res = new BranchInst(cast<BasicBlock>(getValue(Type::LabelTy, Raw->Arg1)),
+			   cast<BasicBlock>(getValue(Type::LabelTy, Raw->Arg2)),
+                                            getValue(Type::BoolTy , Raw->Arg3));
       return false;
     }
     break;
     
   case Instruction::Switch: {
     SwitchInst *I = 
-      new SwitchInst(getValue(Raw.Ty, Raw.Arg1), 
-                     cast<BasicBlock>(getValue(Type::LabelTy, Raw.Arg2)));
+      new SwitchInst(getValue(Raw->Ty, Raw->Arg1), 
+                     cast<BasicBlock>(getValue(Type::LabelTy, Raw->Arg2)));
     Res = I;
-    if (Raw.NumOperands < 3) return false;  // No destinations?  Weird.
+    if (Raw->NumOperands < 3) return false;  // No destinations?  Weird.
 
-    if (Raw.NumOperands == 3 || Raw.VarArgs->size() & 1) {
+    if (Raw->NumOperands == 3 || Raw->VarArgs->size() & 1) {
       std::cerr << "Switch statement with odd number of arguments!\n";
       delete I;
       return true;
     }      
     
-    std::vector<unsigned> &args = *Raw.VarArgs;
+    std::vector<unsigned> &args = *Raw->VarArgs;
     for (unsigned i = 0; i < args.size(); i += 2)
-      I->addCase(cast<Constant>(getValue(Raw.Ty, args[i])),
+      I->addCase(cast<Constant>(getValue(Raw->Ty, args[i])),
                  cast<BasicBlock>(getValue(Type::LabelTy, args[i+1])));
 
-    delete Raw.VarArgs;
+    delete Raw->VarArgs;
     return false;
   }
 
   case Instruction::Call: {
-    Value *F = getValue(Raw.Ty, Raw.Arg1);
+    Value *F = getValue(Raw->Ty, Raw->Arg1);
     if (F == 0) return true;
 
     // Check to make sure we have a pointer to method type
@@ -237,30 +248,30 @@
     if (!FTy->isVarArg()) {
       FunctionType::ParamTypes::const_iterator It = PL.begin();
 
-      switch (Raw.NumOperands) {
+      switch (Raw->NumOperands) {
       case 0: std::cerr << "Invalid call instruction encountered!\n";
 	return true;
       case 1: break;
-      case 2: Params.push_back(getValue(*It++, Raw.Arg2)); break;
-      case 3: Params.push_back(getValue(*It++, Raw.Arg2)); 
+      case 2: Params.push_back(getValue(*It++, Raw->Arg2)); break;
+      case 3: Params.push_back(getValue(*It++, Raw->Arg2)); 
 	if (It == PL.end()) return true;
-	Params.push_back(getValue(*It++, Raw.Arg3)); break;
+	Params.push_back(getValue(*It++, Raw->Arg3)); break;
       default:
-	Params.push_back(getValue(*It++, Raw.Arg2));
+	Params.push_back(getValue(*It++, Raw->Arg2));
 	{
-	  std::vector<unsigned> &args = *Raw.VarArgs;
+	  std::vector<unsigned> &args = *Raw->VarArgs;
 	  for (unsigned i = 0; i < args.size(); i++) {
 	    if (It == PL.end()) return true;
 	    Params.push_back(getValue(*It++, args[i]));
             if (Params.back() == 0) return true;
 	  }
 	}
-	delete Raw.VarArgs;
+	delete Raw->VarArgs;
       }
       if (It != PL.end()) return true;
     } else {
-      if (Raw.NumOperands > 2) {
-	std::vector<unsigned> &args = *Raw.VarArgs;
+      if (Raw->NumOperands > 2) {
+	std::vector<unsigned> &args = *Raw->VarArgs;
 	if (args.size() < 1) return true;
 
 	if ((args.size() & 1) != 0)
@@ -274,7 +285,7 @@
 	  if (V == 0) return true;
 	  Params.push_back(V);
 	}
-	delete Raw.VarArgs;
+	delete Raw->VarArgs;
       }
     }
 
@@ -282,7 +293,7 @@
     return false;
   }
   case Instruction::Invoke: {
-    Value *F = getValue(Raw.Ty, Raw.Arg1);
+    Value *F = getValue(Raw->Ty, Raw->Arg1);
     if (F == 0) return true;
 
     // Check to make sure we have a pointer to method type
@@ -293,16 +304,16 @@
 
     std::vector<Value *> Params;
     const FunctionType::ParamTypes &PL = FTy->getParamTypes();
-    std::vector<unsigned> &args = *Raw.VarArgs;
+    std::vector<unsigned> &args = *Raw->VarArgs;
 
     BasicBlock *Normal, *Except;
 
     if (!FTy->isVarArg()) {
-      if (Raw.NumOperands < 3) return true;
+      if (Raw->NumOperands < 3) return true;
 
-      Normal = cast<BasicBlock>(getValue(Type::LabelTy, Raw.Arg2));
-      if (Raw.NumOperands == 3)
-        Except = cast<BasicBlock>(getValue(Type::LabelTy, Raw.Arg3));
+      Normal = cast<BasicBlock>(getValue(Type::LabelTy, Raw->Arg2));
+      if (Raw->NumOperands == 3)
+        Except = cast<BasicBlock>(getValue(Type::LabelTy, Raw->Arg3));
       else {
         Except = cast<BasicBlock>(getValue(Type::LabelTy, args[0]));
 
@@ -329,105 +340,105 @@
       }
     }
 
-    if (Raw.NumOperands > 3)
-      delete Raw.VarArgs;
+    if (Raw->NumOperands > 3)
+      delete Raw->VarArgs;
     Res = new InvokeInst(F, Normal, Except, Params);
     return false;
   }
   case Instruction::Malloc:
-    if (Raw.NumOperands > 2) return true;
-    V = Raw.NumOperands ? getValue(Type::UIntTy, Raw.Arg1) : 0;
-    if (const PointerType *PTy = dyn_cast<PointerType>(Raw.Ty))
+    if (Raw->NumOperands > 2) return true;
+    V = Raw->NumOperands ? getValue(Type::UIntTy, Raw->Arg1) : 0;
+    if (const PointerType *PTy = dyn_cast<PointerType>(Raw->Ty))
       Res = new MallocInst(PTy->getElementType(), V);
     else
       return true;
     return false;
 
   case Instruction::Alloca:
-    if (Raw.NumOperands > 2) return true;
-    V = Raw.NumOperands ? getValue(Type::UIntTy, Raw.Arg1) : 0;
-    if (const PointerType *PTy = dyn_cast<PointerType>(Raw.Ty))
+    if (Raw->NumOperands > 2) return true;
+    V = Raw->NumOperands ? getValue(Type::UIntTy, Raw->Arg1) : 0;
+    if (const PointerType *PTy = dyn_cast<PointerType>(Raw->Ty))
       Res = new AllocaInst(PTy->getElementType(), V);
     else
       return true;
     return false;
 
   case Instruction::Free:
-    V = getValue(Raw.Ty, Raw.Arg1);
+    V = getValue(Raw->Ty, Raw->Arg1);
     if (!isa<PointerType>(V->getType())) return true;
     Res = new FreeInst(V);
     return false;
 
   case Instruction::GetElementPtr: {
     std::vector<Value*> Idx;
-    if (!isa<PointerType>(Raw.Ty)) return true;
-    const CompositeType *TopTy = dyn_cast<CompositeType>(Raw.Ty);
+    if (!isa<PointerType>(Raw->Ty)) return true;
+    const CompositeType *TopTy = dyn_cast<CompositeType>(Raw->Ty);
 
-    switch (Raw.NumOperands) {
+    switch (Raw->NumOperands) {
     case 0: std::cerr << "Invalid getelementptr encountered!\n"; return true;
     case 1: break;
     case 2:
       if (!TopTy) return true;
-      Idx.push_back(V = getValue(TopTy->getIndexType(), Raw.Arg2));
+      Idx.push_back(V = getValue(TopTy->getIndexType(), Raw->Arg2));
       if (!V) return true;
       break;
     case 3: {
       if (!TopTy) return true;
-      Idx.push_back(V = getValue(TopTy->getIndexType(), Raw.Arg2));
+      Idx.push_back(V = getValue(TopTy->getIndexType(), Raw->Arg2));
       if (!V) return true;
 
       const Type *ETy = GetElementPtrInst::getIndexedType(TopTy, Idx, true);
       const CompositeType *ElTy = dyn_cast_or_null<CompositeType>(ETy);
       if (!ElTy) return true;
 
-      Idx.push_back(V = getValue(ElTy->getIndexType(), Raw.Arg3));
+      Idx.push_back(V = getValue(ElTy->getIndexType(), Raw->Arg3));
       if (!V) return true;
       break;
     }
     default:
       if (!TopTy) return true;
-      Idx.push_back(V = getValue(TopTy->getIndexType(), Raw.Arg2));
+      Idx.push_back(V = getValue(TopTy->getIndexType(), Raw->Arg2));
       if (!V) return true;
 
-      std::vector<unsigned> &args = *Raw.VarArgs;
+      std::vector<unsigned> &args = *Raw->VarArgs;
       for (unsigned i = 0, E = args.size(); i != E; ++i) {
-        const Type *ETy = GetElementPtrInst::getIndexedType(Raw.Ty, Idx, true);
+        const Type *ETy = GetElementPtrInst::getIndexedType(Raw->Ty, Idx, true);
         const CompositeType *ElTy = dyn_cast_or_null<CompositeType>(ETy);
         if (!ElTy) return true;
 	Idx.push_back(V = getValue(ElTy->getIndexType(), args[i]));
 	if (!V) return true;
       }
-      delete Raw.VarArgs; 
+      delete Raw->VarArgs; 
       break;
     }
 
-    Res = new GetElementPtrInst(getValue(Raw.Ty, Raw.Arg1), Idx);
+    Res = new GetElementPtrInst(getValue(Raw->Ty, Raw->Arg1), Idx);
     return false;
   }
 
   case 62:   // volatile load
   case Instruction::Load:
-    if (Raw.NumOperands != 1) return true;
-    if (!isa<PointerType>(Raw.Ty)) return true;
-    Res = new LoadInst(getValue(Raw.Ty, Raw.Arg1), "", Raw.Opcode == 62);
+    if (Raw->NumOperands != 1) return true;
+    if (!isa<PointerType>(Raw->Ty)) return true;
+    Res = new LoadInst(getValue(Raw->Ty, Raw->Arg1), "", Raw->Opcode == 62);
     return false;
 
   case 63:   // volatile store 
   case Instruction::Store: {
-    if (!isa<PointerType>(Raw.Ty) || Raw.NumOperands != 2) return true;
+    if (!isa<PointerType>(Raw->Ty) || Raw->NumOperands != 2) return true;
 
-    Value *Ptr = getValue(Raw.Ty, Raw.Arg2);
+    Value *Ptr = getValue(Raw->Ty, Raw->Arg2);
     const Type *ValTy = cast<PointerType>(Ptr->getType())->getElementType();
-    Res = new StoreInst(getValue(ValTy, Raw.Arg1), Ptr, Raw.Opcode == 63);
+    Res = new StoreInst(getValue(ValTy, Raw->Arg1), Ptr, Raw->Opcode == 63);
     return false;
   }
   case Instruction::Unwind:
-    if (Raw.NumOperands != 0) return true;
+    if (Raw->NumOperands != 0) return true;
     Res = new UnwindInst();
     return false;
-  }  // end switch(Raw.Opcode) 
+  }  // end switch(Raw->Opcode) 
 
-  std::cerr << "Unrecognized instruction! " << Raw.Opcode 
+  std::cerr << "Unrecognized instruction! " << Raw->Opcode 
             << " ADDR = 0x" << (void*)Buf << "\n";
   return true;
 }