Land the long talked about "type system rewrite" patch. This

patch brings numerous advantages to LLVM.  One way to look at it
is through diffstat:
 109 files changed, 3005 insertions(+), 5906 deletions(-)

Removing almost 3K lines of code is a good thing.  Other advantages
include:

1. Value::getType() is a simple load that can be CSE'd, not a mutating
   union-find operation.
2. Types a uniqued and never move once created, defining away PATypeHolder.
3. Structs can be "named" now, and their name is part of the identity that
   uniques them.  This means that the compiler doesn't merge them structurally
   which makes the IR much less confusing.
4. Now that there is no way to get a cycle in a type graph without a named
   struct type, "upreferences" go away.
5. Type refinement is completely gone, which should make LTO much MUCH faster
   in some common cases with C++ code.
6. Types are now generally immutable, so we can use "Type *" instead 
   "const Type *" everywhere.

Downsides of this patch are that it removes some functions from the C API,
so people using those will have to upgrade to (not yet added) new API.  
"LLVM 3.0" is the right time to do this.

There are still some cleanups pending after this, this patch is large enough
as-is.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134829 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 89 insertions, 267 deletions

diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index c59497efc2..54072b2f8d 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -20,7 +20,6 @@
 #include "llvm/Instructions.h"
 #include "llvm/Pass.h"
 #include "llvm/PassManager.h"
-#include "llvm/TypeSymbolTable.h"
 #include "llvm/Intrinsics.h"
 #include "llvm/IntrinsicInst.h"
 #include "llvm/InlineAsm.h"
@@ -74,29 +73,6 @@ namespace {
       PrivateGlobalPrefix = "";
     }
   };
-  /// CBackendNameAllUsedStructsAndMergeFunctions - This pass inserts names for
-  /// any unnamed structure types that are used by the program, and merges
-  /// external functions with the same name.
-  ///
-  class CBackendNameAllUsedStructsAndMergeFunctions : public ModulePass {
-  public:
-    static char ID;
-    CBackendNameAllUsedStructsAndMergeFunctions()
-        : ModulePass(ID) {
-          initializeFindUsedTypesPass(*PassRegistry::getPassRegistry());
-        }
-    void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addRequired<FindUsedTypes>();
-    }
-
-    virtual const char *getPassName() const {
-      return "C backend type canonicalizer";
-    }
-
-    virtual bool runOnModule(Module &M);
-  };
-
-  char CBackendNameAllUsedStructsAndMergeFunctions::ID = 0;
 
   /// CWriter - This class is the main chunk of code that converts an LLVM
   /// module to a C translation unit.
@@ -109,7 +85,7 @@ namespace {
     const MCAsmInfo* TAsm;
     MCContext *TCtx;
     const TargetData* TD;
-    std::map<const Type *, std::string> TypeNames;
+    
     std::map<const ConstantFP *, unsigned> FPConstantMap;
     std::set<Function*> intrinsicPrototypesAlreadyGenerated;
     std::set<const Argument*> ByValParams;
@@ -118,6 +94,10 @@ namespace {
     DenseMap<const Value*, unsigned> AnonValueNumbers;
     unsigned NextAnonValueNumber;
 
+    /// UnnamedStructIDs - This contains a unique ID for each struct that is
+    /// either anonymous or has no name.
+    DenseMap<const StructType*, unsigned> UnnamedStructIDs;
+    
   public:
     static char ID;
     explicit CWriter(formatted_raw_ostream &o)
@@ -163,9 +143,9 @@ namespace {
       delete TCtx;
       delete TAsm;
       FPConstantMap.clear();
-      TypeNames.clear();
       ByValParams.clear();
       intrinsicPrototypesAlreadyGenerated.clear();
+      UnnamedStructIDs.clear();
       return false;
     }
 
@@ -182,6 +162,8 @@ namespace {
                                               const AttrListPtr &PAL,
                                               const PointerType *Ty);
 
+    std::string getStructName(const StructType *ST);
+    
     /// writeOperandDeref - Print the result of dereferencing the specified
     /// operand with '*'.  This is equivalent to printing '*' then using
     /// writeOperand, but avoids excess syntax in some cases.
@@ -214,8 +196,8 @@ namespace {
     /// intrinsics which need to be explicitly defined in the CBackend.
     void printIntrinsicDefinition(const Function &F, raw_ostream &Out);
 
-    void printModuleTypes(const TypeSymbolTable &ST);
-    void printContainedStructs(const Type *Ty, std::set<const Type *> &);
+    void printModuleTypes();
+    void printContainedStructs(const Type *Ty, SmallPtrSet<const Type *, 16> &);
     void printFloatingPointConstants(Function &F);
     void printFloatingPointConstants(const Constant *C);
     void printFunctionSignature(const Function *F, bool Prototype);
@@ -359,6 +341,7 @@ namespace {
 char CWriter::ID = 0;
 
 
+
 static std::string CBEMangle(const std::string &S) {
   std::string Result;
 
@@ -374,90 +357,14 @@ static std::string CBEMangle(const std::string &S) {
   return Result;
 }
 
-
-/// This method inserts names for any unnamed structure types that are used by
-/// the program, and removes names from structure types that are not used by the
-/// program.
-///
-bool CBackendNameAllUsedStructsAndMergeFunctions::runOnModule(Module &M) {
-  // Get a set of types that are used by the program...
-  SetVector<const Type *> UT = getAnalysis<FindUsedTypes>().getTypes();
-
-  // Loop over the module symbol table, removing types from UT that are
-  // already named, and removing names for types that are not used.
-  //
-  TypeSymbolTable &TST = M.getTypeSymbolTable();
-  for (TypeSymbolTable::iterator TI = TST.begin(), TE = TST.end();
-       TI != TE; ) {
-    TypeSymbolTable::iterator I = TI++;
-
-    // If this isn't a struct or array type, remove it from our set of types
-    // to name. This simplifies emission later.
-    if (!I->second->isStructTy() && !I->second->isOpaqueTy() &&
-        !I->second->isArrayTy()) {
-      TST.remove(I);
-    } else {
-      // If this is not used, remove it from the symbol table.
-      if (!UT.count(I->second))
-        TST.remove(I);
-      else
-        UT.remove(I->second); // Only keep one name for this type.
-    }
-  }
-
-  // UT now contains types that are not named.  Loop over it, naming
-  // structure types.
-  //
-  bool Changed = false;
-  unsigned RenameCounter = 0;
-  for (SetVector<const Type *>::const_iterator I = UT.begin(), E = UT.end();
-       I != E; ++I)
-    if ((*I)->isStructTy() || (*I)->isArrayTy()) {
-      while (M.addTypeName("unnamed"+utostr(RenameCounter), *I))
-        ++RenameCounter;
-      Changed = true;
-    }
-
-
-  // Loop over all external functions and globals.  If we have two with
-  // identical names, merge them.
-  // FIXME: This code should disappear when we don't allow values with the same
-  // names when they have different types!
-  std::map<std::string, GlobalValue*> ExtSymbols;
-  for (Module::iterator I = M.begin(), E = M.end(); I != E;) {
-    Function *GV = I++;
-    if (GV->isDeclaration() && GV->hasName()) {
-      std::pair<std::map<std::string, GlobalValue*>::iterator, bool> X
-        = ExtSymbols.insert(std::make_pair(GV->getName(), GV));
-      if (!X.second) {
-        // Found a conflict, replace this global with the previous one.
-        GlobalValue *OldGV = X.first->second;
-        GV->replaceAllUsesWith(ConstantExpr::getBitCast(OldGV, GV->getType()));
-        GV->eraseFromParent();
-        Changed = true;
-      }
-    }
-  }
-  // Do the same for globals.
-  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
-       I != E;) {
-    GlobalVariable *GV = I++;
-    if (GV->isDeclaration() && GV->hasName()) {
-      std::pair<std::map<std::string, GlobalValue*>::iterator, bool> X
-        = ExtSymbols.insert(std::make_pair(GV->getName(), GV));
-      if (!X.second) {
-        // Found a conflict, replace this global with the previous one.
-        GlobalValue *OldGV = X.first->second;
-        GV->replaceAllUsesWith(ConstantExpr::getBitCast(OldGV, GV->getType()));
-        GV->eraseFromParent();
-        Changed = true;
-      }
-    }
-  }
-
-  return Changed;
+std::string CWriter::getStructName(const StructType *ST) {
+  if (!ST->isAnonymous() && !ST->getName().empty())
+    return CBEMangle("l_"+ST->getName().str());
+  
+  return "l_unnamed_" + utostr(UnnamedStructIDs[ST]);
 }
 
+
 /// printStructReturnPointerFunctionType - This is like printType for a struct
 /// return type, except, instead of printing the type as void (*)(Struct*, ...)
 /// print it as "Struct (*)(...)", for struct return functions.
@@ -471,7 +378,7 @@ void CWriter::printStructReturnPointerFunctionType(raw_ostream &Out,
   bool PrintedType = false;
 
   FunctionType::param_iterator I = FTy->param_begin(), E = FTy->param_end();
-  const Type *RetTy = cast<PointerType>(I->get())->getElementType();
+  const Type *RetTy = cast<PointerType>(*I)->getElementType();
   unsigned Idx = 1;
   for (++I, ++Idx; I != E; ++I, ++Idx) {
     if (PrintedType)
@@ -559,12 +466,6 @@ raw_ostream &CWriter::printType(raw_ostream &Out, const Type *Ty,
     return Out;
   }
 
-  // Check to see if the type is named.
-  if (!IgnoreName || Ty->isOpaqueTy()) {
-    std::map<const Type *, std::string>::iterator I = TypeNames.find(Ty);
-    if (I != TypeNames.end()) return Out << I->second << ' ' << NameSoFar;
-  }
-
   switch (Ty->getTypeID()) {
   case Type::FunctionTyID: {
     const FunctionType *FTy = cast<FunctionType>(Ty);
@@ -599,6 +500,11 @@ raw_ostream &CWriter::printType(raw_ostream &Out, const Type *Ty,
   }
   case Type::StructTyID: {
     const StructType *STy = cast<StructType>(Ty);
+    
+    // Check to see if the type is named.
+    if (!IgnoreName)
+      return Out << getStructName(STy) << ' ' << NameSoFar;
+    
     Out << NameSoFar + " {\n";
     unsigned Idx = 0;
     for (StructType::element_iterator I = STy->element_begin(),
@@ -639,12 +545,6 @@ raw_ostream &CWriter::printType(raw_ostream &Out, const Type *Ty,
     return Out << "; }";
   }
 
-  case Type::OpaqueTyID: {
-    std::string TyName = "struct opaque_" + itostr(OpaqueCounter++);
-    assert(TypeNames.find(Ty) == TypeNames.end());
-    TypeNames[Ty] = TyName;
-    return Out << TyName << ' ' << NameSoFar;
-  }
   default:
     llvm_unreachable("Unhandled case in getTypeProps!");
   }
@@ -1829,8 +1729,8 @@ bool CWriter::doInitialization(Module &M) {
         << "/* End Module asm statements */\n";
   }
 
-  // Loop over the symbol table, emitting all named constants...
-  printModuleTypes(M.getTypeSymbolTable());
+  // Loop over the symbol table, emitting all named constants.
+  printModuleTypes();
 
   // Global variable declarations...
   if (!M.global_empty()) {
@@ -2119,11 +2019,10 @@ void CWriter::printFloatingPointConstants(const Constant *C) {
 }
 
 
-
 /// printSymbolTable - Run through symbol table looking for type names.  If a
 /// type name is found, emit its declaration...
 ///
-void CWriter::printModuleTypes(const TypeSymbolTable &TST) {
+void CWriter::printModuleTypes() {
   Out << "/* Helper union for bitcasts */\n";
   Out << "typedef union {\n";
   Out << "  unsigned int Int32;\n";
@@ -2132,46 +2031,42 @@ void CWriter::printModuleTypes(const TypeSymbolTable &TST) {
   Out << "  double Double;\n";
   Out << "} llvmBitCastUnion;\n";
 
-  // We are only interested in the type plane of the symbol table.
-  TypeSymbolTable::const_iterator I   = TST.begin();
-  TypeSymbolTable::const_iterator End = TST.end();
+  // Get all of the struct types used in the module.
+  std::vector<StructType*> StructTypes;
+  TheModule->findUsedStructTypes(StructTypes);
 
-  // If there are no type names, exit early.
-  if (I == End) return;
+  if (StructTypes.empty()) return;
 
-  // Print out forward declarations for structure types before anything else!
   Out << "/* Structure forward decls */\n";
-  for (; I != End; ++I) {
-    std::string Name = "struct " + CBEMangle("l_"+I->first);
-    Out << Name << ";\n";
-    TypeNames.insert(std::make_pair(I->second, Name));
-  }
 
-  Out << '\n';
+  unsigned NextTypeID = 0;
+  
+  // If any of them are missing names, add a unique ID to UnnamedStructIDs.
+  // Print out forward declarations for structure types.
+  for (unsigned i = 0, e = StructTypes.size(); i != e; ++i) {
+    StructType *ST = StructTypes[i];
 
-  // Now we can print out typedefs.  Above, we guaranteed that this can only be
-  // for struct or opaque types.
-  Out << "/* Typedefs */\n";
-  for (I = TST.begin(); I != End; ++I) {
-    std::string Name = CBEMangle("l_"+I->first);
-    Out << "typedef ";
-    printType(Out, I->second, false, Name);
-    Out << ";\n";
+    if (ST->isAnonymous() || ST->getName().empty())
+      UnnamedStructIDs[ST] = NextTypeID++;
+
+    std::string Name = getStructName(ST);
+
+    Out << "typedef struct " << Name << ' ' << Name << ";\n";
   }
 
   Out << '\n';
 
-  // Keep track of which structures have been printed so far...
-  std::set<const Type *> StructPrinted;
+  // Keep track of which structures have been printed so far.
+  SmallPtrSet<const Type *, 16> StructPrinted;
 
   // Loop over all structures then push them into the stack so they are
   // printed in the correct order.
   //
   Out << "/* Structure contents */\n";
-  for (I = TST.begin(); I != End; ++I)
-    if (I->second->isStructTy() || I->second->isArrayTy())
+  for (unsigned i = 0, e = StructTypes.size(); i != e; ++i)
+    if (StructTypes[i]->isStructTy())
       // Only print out used types!
-      printContainedStructs(I->second, StructPrinted);
+      printContainedStructs(StructTypes[i], StructPrinted);
 }
 
 // Push the struct onto the stack and recursively push all structs
@@ -2180,7 +2075,7 @@ void CWriter::printModuleTypes(const TypeSymbolTable &TST) {
 // TODO:  Make this work properly with vector types
 //
 void CWriter::printContainedStructs(const Type *Ty,
-                                    std::set<const Type*> &StructPrinted) {
+                                SmallPtrSet<const Type *, 16> &StructPrinted) {
   // Don't walk through pointers.
   if (Ty->isPointerTy() || Ty->isPrimitiveType() || Ty->isIntegerTy())
     return;
@@ -2190,14 +2085,13 @@ void CWriter::printContainedStructs(const Type *Ty,
        E = Ty->subtype_end(); I != E; ++I)
     printContainedStructs(*I, StructPrinted);
 
-  if (Ty->isStructTy() || Ty->isArrayTy()) {
+  if (const StructType *ST = dyn_cast<StructType>(Ty)) {
     // Check to see if we have already printed this struct.
-    if (StructPrinted.insert(Ty).second) {
-      // Print structure type out.
-      std::string Name = TypeNames[Ty];
-      printType(Out, Ty, false, Name, true);
-      Out << ";\n\n";
-    }
+    if (!StructPrinted.insert(Ty)) return;
+    
+    // Print structure type out.
+    printType(Out, ST, false, getStructName(ST), true);
+    Out << ";\n\n";
   }
 }
 
@@ -2847,10 +2741,12 @@ static void printLimitValue(const IntegerType &Ty, bool isSigned, bool isMax,
     Out << "U" << type << (isMax ? "_MAX" : "0");
 }
 
+#ifndef NDEBUG
 static bool isSupportedIntegerSize(const IntegerType &T) {
   return T.getBitWidth() == 8 || T.getBitWidth() == 16 ||
          T.getBitWidth() == 32 || T.getBitWidth() == 64;
 }
+#endif
 
 void CWriter::printIntrinsicDefinition(const Function &F, raw_ostream &Out) {
   const FunctionType *funT = F.getFunctionType();
@@ -3704,7 +3600,6 @@ bool CTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
   PM.add(createGCLoweringPass());
   PM.add(createLowerInvokePass());
   PM.add(createCFGSimplificationPass());   // clean up after lower invoke.
-  PM.add(new CBackendNameAllUsedStructsAndMergeFunctions());
   PM.add(new CWriter(o));
   PM.add(createGCInfoDeleter());
   return false;
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index 351f12225c..c4280ef5a2 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -22,7 +22,7 @@
 #include "llvm/Module.h"
 #include "llvm/Pass.h"
 #include "llvm/PassManager.h"
-#include "llvm/TypeSymbolTable.h"
+#include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Support/CommandLine.h"
@@ -33,7 +33,7 @@
 #include "llvm/Config/config.h"
 #include <algorithm>
 #include <set>
-
+#include <map>
 using namespace llvm;
 
 static cl::opt<std::string>
@@ -193,26 +193,11 @@ static std::string getTypePrefix(const Type *Ty) {
   case Type::ArrayTyID:    return "array_";
   case Type::PointerTyID:  return "ptr_";
   case Type::VectorTyID:   return "packed_";
-  case Type::OpaqueTyID:   return "opaque_";
   default:                 return "other_";
   }
   return "unknown_";
 }
 
-// Looks up the type in the symbol table and returns a pointer to its name or
-// a null pointer if it wasn't found. Note that this isn't the same as the
-// Mode::getTypeName function which will return an empty string, not a null
-// pointer if the name is not found.
-static const std::string *
-findTypeName(const TypeSymbolTable& ST, const Type* Ty) {
-  TypeSymbolTable::const_iterator TI = ST.begin();
-  TypeSymbolTable::const_iterator TE = ST.end();
-  for (;TI != TE; ++TI)
-    if (TI->second == Ty)
-      return &(TI->first);
-  return 0;
-}
-
 void CppWriter::error(const std::string& msg) {
   report_fatal_error(msg);
 }
@@ -384,18 +369,20 @@ std::string CppWriter::getCppName(const Type* Ty) {
   case Type::StructTyID:      prefix = "StructTy_"; break;
   case Type::ArrayTyID:       prefix = "ArrayTy_"; break;
   case Type::PointerTyID:     prefix = "PointerTy_"; break;
-  case Type::OpaqueTyID:      prefix = "OpaqueTy_"; break;
   case Type::VectorTyID:      prefix = "VectorTy_"; break;
   default:                    prefix = "OtherTy_"; break; // prevent breakage
   }
 
   // See if the type has a name in the symboltable and build accordingly
-  const std::string* tName = findTypeName(TheModule->getTypeSymbolTable(), Ty);
   std::string name;
-  if (tName)
-    name = std::string(prefix) + *tName;
-  else
-    name = std::string(prefix) + utostr(uniqueNum++);
+  if (const StructType *STy = dyn_cast<StructType>(Ty))
+    if (STy->hasName())
+      name = STy->getName();
+  
+  if (name.empty())
+    name = utostr(uniqueNum++);
+  
+  name = std::string(prefix) + name;
   sanitize(name);
 
   // Save the name
@@ -590,8 +577,18 @@ bool CppWriter::printTypeInternal(const Type* Ty) {
       Out << ");";
       nl(Out);
     }
-    Out << "StructType* " << typeName << " = StructType::get("
-        << typeName << "_fields, /*isPacked=*/"
+    
+    Out << "StructType *" << typeName << " = ";
+    if (ST->isAnonymous()) {
+      Out << "StructType::get(" << "mod->getContext(), ";
+    } else {
+      Out << "StructType::createNamed(mod->getContext(), \"";
+      printEscapedString(ST->getName());
+      Out << "\");";
+      nl(Out);
+      Out << typeName << "->setBody(";
+    }
+    Out << typeName << "_fields, /*isPacked=*/"
         << (ST->isPacked() ? "true" : "false") << ");";
     nl(Out);
     break;
@@ -629,25 +626,10 @@ bool CppWriter::printTypeInternal(const Type* Ty) {
     nl(Out);
     break;
   }
-  case Type::OpaqueTyID: {
-    Out << "OpaqueType* " << typeName;
-    Out << " = OpaqueType::get(mod->getContext());";
-    nl(Out);
-    break;
-  }
   default:
     error("Invalid TypeID");
   }
 
-  // If the type had a name, make sure we recreate it.
-  const std::string* progTypeName =
-    findTypeName(TheModule->getTypeSymbolTable(),Ty);
-  if (progTypeName) {
-    Out << "mod->addTypeName(\"" << *progTypeName << "\", "
-        << typeName << ");";
-    nl(Out);
-  }
-
   // Pop us off the type stack
   TypeStack.pop_back();
 
@@ -670,7 +652,6 @@ bool CppWriter::printTypeInternal(const Type* Ty) {
     case Type::StructTyID:   Out << "StructType"; break;
     case Type::VectorTyID:   Out << "VectorType"; break;
     case Type::PointerTyID:  Out << "PointerType"; break;
-    case Type::OpaqueTyID:   Out << "OpaqueType"; break;
     default:                 Out << "NoSuchDerivedType"; break;
     }
     Out << ">(" << I->second << "_fwd.get());";
@@ -695,26 +676,7 @@ void CppWriter::printType(const Type* Ty) {
 }
 
 void CppWriter::printTypes(const Module* M) {
-  // Walk the symbol table and print out all its types
-  const TypeSymbolTable& symtab = M->getTypeSymbolTable();
-  for (TypeSymbolTable::const_iterator TI = symtab.begin(), TE = symtab.end();
-       TI != TE; ++TI) {
-
-    // For primitive types and types already defined, just add a name
-    TypeMap::const_iterator TNI = TypeNames.find(TI->second);
-    if (TI->second->isIntegerTy() || TI->second->isPrimitiveType() ||
-        TNI != TypeNames.end()) {
-      Out << "mod->addTypeName(\"";
-      printEscapedString(TI->first);
-      Out << "\", " << getCppName(TI->second) << ");";
-      nl(Out);
-      // For everything else, define the type
-    } else {
-      printType(TI->second);
-    }
-  }
-
-  // Add all of the global variables to the value table...
+  // Add all of the global variables to the value table.
   for (Module::const_global_iterator I = TheModule->global_begin(),
          E = TheModule->global_end(); I != E; ++I) {
     if (I->hasInitializer())
@@ -1959,8 +1921,8 @@ void CppWriter::printVariable(const std::string& fname,
   Out << "}\n";
 }
 
-void CppWriter::printType(const std::string& fname,
-                          const std::string& typeName) {
+void CppWriter::printType(const std::string &fname,
+                          const std::string &typeName) {
   const Type* Ty = TheModule->getTypeByName(typeName);
   if (!Ty) {
     error(std::string("Type '") + typeName + "' not found in input module");
diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index 1990bc7b92..6309a1572c 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -42,6 +42,7 @@ char TargetData::ID = 0;
 //===----------------------------------------------------------------------===//
 
 StructLayout::StructLayout(const StructType *ST, const TargetData &TD) {
+  assert(!ST->isOpaque() && "Cannot get layout of opaque structs");
   StructAlignment = 0;
   StructSize = 0;
   NumElements = ST->getNumElements();
@@ -313,52 +314,16 @@ unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType,
 
 namespace {
 
-class StructLayoutMap : public AbstractTypeUser {
+class StructLayoutMap {
   typedef DenseMap<const StructType*, StructLayout*> LayoutInfoTy;
   LayoutInfoTy LayoutInfo;
 
-  void RemoveEntry(LayoutInfoTy::iterator I, bool WasAbstract) {
-    I->second->~StructLayout();
-    free(I->second);
-    if (WasAbstract)
-      I->first->removeAbstractTypeUser(this);
-    LayoutInfo.erase(I);
-  }
-
-
-  /// refineAbstractType - The callback method invoked when an abstract type is
-  /// resolved to another type.  An object must override this method to update
-  /// its internal state to reference NewType instead of OldType.
-  ///
-  virtual void refineAbstractType(const DerivedType *OldTy,
-                                  const Type *) {
-    LayoutInfoTy::iterator I = LayoutInfo.find(cast<const StructType>(OldTy));
-    assert(I != LayoutInfo.end() && "Using type but not in map?");
-    RemoveEntry(I, true);
-  }
-
-  /// typeBecameConcrete - The other case which AbstractTypeUsers must be aware
-  /// of is when a type makes the transition from being abstract (where it has
-  /// clients on its AbstractTypeUsers list) to concrete (where it does not).
-  /// This method notifies ATU's when this occurs for a type.
-  ///
-  virtual void typeBecameConcrete(const DerivedType *AbsTy) {
-    LayoutInfoTy::iterator I = LayoutInfo.find(cast<const StructType>(AbsTy));
-    assert(I != LayoutInfo.end() && "Using type but not in map?");
-    RemoveEntry(I, true);
-  }
-
 public:
   virtual ~StructLayoutMap() {
     // Remove any layouts.
-    for (LayoutInfoTy::iterator
-           I = LayoutInfo.begin(), E = LayoutInfo.end(); I != E; ++I) {
-      const Type *Key = I->first;
+    for (LayoutInfoTy::iterator I = LayoutInfo.begin(), E = LayoutInfo.end();
+         I != E; ++I) {
       StructLayout *Value = I->second;
-
-      if (Key->isAbstract())
-        Key->removeAbstractTypeUser(this);
-
       Value->~StructLayout();
       free(Value);
     }
@@ -367,7 +332,10 @@ public:
   void InvalidateEntry(const StructType *Ty) {
     LayoutInfoTy::iterator I = LayoutInfo.find(Ty);
     if (I == LayoutInfo.end()) return;
-    RemoveEntry(I, Ty->isAbstract());
+    
+    I->second->~StructLayout();
+    free(I->second);
+    LayoutInfo.erase(I);
   }
 
   StructLayout *&operator[](const StructType *STy) {
@@ -404,9 +372,6 @@ const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
 
   new (L) StructLayout(Ty, *this);
 
-  if (Ty->isAbstract())
-    Ty->addAbstractTypeUser(STM);
-
   return L;
 }