Fix a couple of bugs, add some new cool stuff.

1. Fix a todo in Parser::ParseTag, to recover better.  On code like
   that in test/Sema/decl-invalid.c it causes us to return a single
   error instead of multiple.
2. Fix an error in Sema::ParseDeclarator, where it would crash if the
   declarator didn't have an identifier.  Instead, diagnose the problem.
3. Start adding infrastructure to track the range of locations covered
   by a declspec or declarator.  This is mostly implemented for declspec,
   but could be improved, it is missing for declarator.

Thanks to Neil for pointing out this crash.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40482 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/AST/ASTContext.cpp b/AST/ASTContext.cpp
new file mode 100644
index 0000000..a9fb81f
--- /dev/null
+++ b/AST/ASTContext.cpp
@@ -0,0 +1,718 @@
+//===--- ASTContext.cpp - Context to hold long-lived AST nodes ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the ASTContext interface.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Basic/TargetInfo.h"
+#include "llvm/ADT/SmallVector.h"
+using namespace clang;
+
+enum FloatingRank {
+  FloatRank, DoubleRank, LongDoubleRank
+};
+
+ASTContext::~ASTContext() {
+  // Deallocate all the types.
+  while (!Types.empty()) {
+    if (FunctionTypeProto *FT = dyn_cast<FunctionTypeProto>(Types.back())) {
+      // Destroy the object, but don't call delete.  These are malloc'd.
+      FT->~FunctionTypeProto();
+      free(FT);
+    } else {
+      delete Types.back();
+    }
+    Types.pop_back();
+  }
+}
+
+void ASTContext::PrintStats() const {
+  fprintf(stderr, "*** AST Context Stats:\n");
+  fprintf(stderr, "  %d types total.\n", (int)Types.size());
+  unsigned NumBuiltin = 0, NumPointer = 0, NumArray = 0, NumFunctionP = 0;
+  unsigned NumVector = 0, NumComplex = 0;
+  unsigned NumFunctionNP = 0, NumTypeName = 0, NumTagged = 0, NumReference = 0;
+  
+  unsigned NumTagStruct = 0, NumTagUnion = 0, NumTagEnum = 0, NumTagClass = 0;
+  
+  for (unsigned i = 0, e = Types.size(); i != e; ++i) {
+    Type *T = Types[i];
+    if (isa<BuiltinType>(T))
+      ++NumBuiltin;
+    else if (isa<PointerType>(T))
+      ++NumPointer;
+    else if (isa<ReferenceType>(T))
+      ++NumReference;
+    else if (isa<ComplexType>(T))
+      ++NumComplex;
+    else if (isa<ArrayType>(T))
+      ++NumArray;
+    else if (isa<VectorType>(T))
+      ++NumVector;
+    else if (isa<FunctionTypeNoProto>(T))
+      ++NumFunctionNP;
+    else if (isa<FunctionTypeProto>(T))
+      ++NumFunctionP;
+    else if (isa<TypedefType>(T))
+      ++NumTypeName;
+    else if (TagType *TT = dyn_cast<TagType>(T)) {
+      ++NumTagged;
+      switch (TT->getDecl()->getKind()) {
+      default: assert(0 && "Unknown tagged type!");
+      case Decl::Struct: ++NumTagStruct; break;
+      case Decl::Union:  ++NumTagUnion; break;
+      case Decl::Class:  ++NumTagClass; break; 
+      case Decl::Enum:   ++NumTagEnum; break;
+      }
+    } else {
+      assert(0 && "Unknown type!");
+    }
+  }
+
+  fprintf(stderr, "    %d builtin types\n", NumBuiltin);
+  fprintf(stderr, "    %d pointer types\n", NumPointer);
+  fprintf(stderr, "    %d reference types\n", NumReference);
+  fprintf(stderr, "    %d complex types\n", NumComplex);
+  fprintf(stderr, "    %d array types\n", NumArray);
+  fprintf(stderr, "    %d vector types\n", NumVector);
+  fprintf(stderr, "    %d function types with proto\n", NumFunctionP);
+  fprintf(stderr, "    %d function types with no proto\n", NumFunctionNP);
+  fprintf(stderr, "    %d typename (typedef) types\n", NumTypeName);
+  fprintf(stderr, "    %d tagged types\n", NumTagged);
+  fprintf(stderr, "      %d struct types\n", NumTagStruct);
+  fprintf(stderr, "      %d union types\n", NumTagUnion);
+  fprintf(stderr, "      %d class types\n", NumTagClass);
+  fprintf(stderr, "      %d enum types\n", NumTagEnum);
+  fprintf(stderr, "Total bytes = %d\n", int(NumBuiltin*sizeof(BuiltinType)+
+    NumPointer*sizeof(PointerType)+NumArray*sizeof(ArrayType)+
+    NumComplex*sizeof(ComplexType)+NumVector*sizeof(VectorType)+
+    NumFunctionP*sizeof(FunctionTypeProto)+
+    NumFunctionNP*sizeof(FunctionTypeNoProto)+
+    NumTypeName*sizeof(TypedefType)+NumTagged*sizeof(TagType)));
+}
+
+
+void ASTContext::InitBuiltinType(QualType &R, BuiltinType::Kind K) {
+  Types.push_back((R = QualType(new BuiltinType(K),0)).getTypePtr());
+}
+
+
+void ASTContext::InitBuiltinTypes() {
+  assert(VoidTy.isNull() && "Context reinitialized?");
+  
+  // C99 6.2.5p19.
+  InitBuiltinType(VoidTy,              BuiltinType::Void);
+  
+  // C99 6.2.5p2.
+  InitBuiltinType(BoolTy,              BuiltinType::Bool);
+  // C99 6.2.5p3.
+  if (Target.isCharSigned(SourceLocation()))
+    InitBuiltinType(CharTy,            BuiltinType::Char_S);
+  else
+    InitBuiltinType(CharTy,            BuiltinType::Char_U);
+  // C99 6.2.5p4.
+  InitBuiltinType(SignedCharTy,        BuiltinType::SChar);
+  InitBuiltinType(ShortTy,             BuiltinType::Short);
+  InitBuiltinType(IntTy,               BuiltinType::Int);
+  InitBuiltinType(LongTy,              BuiltinType::Long);
+  InitBuiltinType(LongLongTy,          BuiltinType::LongLong);
+  
+  // C99 6.2.5p6.
+  InitBuiltinType(UnsignedCharTy,      BuiltinType::UChar);
+  InitBuiltinType(UnsignedShortTy,     BuiltinType::UShort);
+  InitBuiltinType(UnsignedIntTy,       BuiltinType::UInt);
+  InitBuiltinType(UnsignedLongTy,      BuiltinType::ULong);
+  InitBuiltinType(UnsignedLongLongTy,  BuiltinType::ULongLong);
+  
+  // C99 6.2.5p10.
+  InitBuiltinType(FloatTy,             BuiltinType::Float);
+  InitBuiltinType(DoubleTy,            BuiltinType::Double);
+  InitBuiltinType(LongDoubleTy,        BuiltinType::LongDouble);
+  
+  // C99 6.2.5p11.
+  FloatComplexTy      = getComplexType(FloatTy);
+  DoubleComplexTy     = getComplexType(DoubleTy);
+  LongDoubleComplexTy = getComplexType(LongDoubleTy);
+}
+
+//===----------------------------------------------------------------------===//
+//                         Type Sizing and Analysis
+//===----------------------------------------------------------------------===//
+
+/// getTypeSize - Return the size of the specified type, in bits.  This method
+/// does not work on incomplete types.
+std::pair<uint64_t, unsigned>
+ASTContext::getTypeInfo(QualType T, SourceLocation L) {
+  T = T.getCanonicalType();
+  uint64_t Size;
+  unsigned Align;
+  switch (T->getTypeClass()) {
+  case Type::TypeName: assert(0 && "Not a canonical type!");
+  case Type::FunctionNoProto:
+  case Type::FunctionProto:
+  default:
+    assert(0 && "Incomplete types have no size!");
+  case Type::Array: {
+    std::pair<uint64_t, unsigned> EltInfo = 
+      getTypeInfo(cast<ArrayType>(T)->getElementType(), L);
+    
+    // Get the size of the array.
+    llvm::APSInt Sz(32);
+    if (!cast<ArrayType>(T)->getSizeExpr()->isIntegerConstantExpr(Sz, *this))
+      assert(0 && "VLAs not implemented yet!");
+    
+    Size = EltInfo.first*Sz.getZExtValue();
+    Align = EltInfo.second;
+    break;
+  }    
+  case Type::Vector: {
+    std::pair<uint64_t, unsigned> EltInfo = 
+      getTypeInfo(cast<VectorType>(T)->getElementType(), L);
+    Size = EltInfo.first*cast<VectorType>(T)->getNumElements();
+    // FIXME: Vector alignment is not the alignment of its elements.
+    Align = EltInfo.second;
+    break;
+  }
+
+  case Type::Builtin: {
+    // FIXME: need to use TargetInfo to derive the target specific sizes. This
+    // implementation will suffice for play with vector support.
+    switch (cast<BuiltinType>(T)->getKind()) {
+    default: assert(0 && "Unknown builtin type!");
+    case BuiltinType::Void:
+      assert(0 && "Incomplete types have no size!");
+    case BuiltinType::Bool:       Target.getBoolInfo(Size, Align, L); break;
+    case BuiltinType::Char_S:
+    case BuiltinType::Char_U:
+    case BuiltinType::UChar:
+    case BuiltinType::SChar:      Target.getCharInfo(Size, Align, L); break;
+    case BuiltinType::UShort:
+    case BuiltinType::Short:      Target.getShortInfo(Size, Align, L); break;
+    case BuiltinType::UInt:
+    case BuiltinType::Int:        Target.getIntInfo(Size, Align, L); break;
+    case BuiltinType::ULong:
+    case BuiltinType::Long:       Target.getLongInfo(Size, Align, L); break;
+    case BuiltinType::ULongLong:
+    case BuiltinType::LongLong:   Target.getLongLongInfo(Size, Align, L); break;
+    case BuiltinType::Float:      Target.getFloatInfo(Size, Align, L); break;
+    case BuiltinType::Double:     Target.getDoubleInfo(Size, Align, L); break;
+    case BuiltinType::LongDouble: Target.getLongDoubleInfo(Size, Align,L);break;
+    }
+    break;
+  }
+  case Type::Pointer: Target.getPointerInfo(Size, Align, L); break;
+  case Type::Reference:
+    // "When applied to a reference or a reference type, the result is the size
+    // of the referenced type." C++98 5.3.3p2: expr.sizeof.
+    // FIXME: This is wrong for struct layout!
+    return getTypeInfo(cast<ReferenceType>(T)->getReferenceeType(), L);
+    
+  case Type::Complex: {
+    // Complex types have the same alignment as their elements, but twice the
+    // size.
+    std::pair<uint64_t, unsigned> EltInfo = 
+      getTypeInfo(cast<ComplexType>(T)->getElementType(), L);
+    Size = EltInfo.first*2;
+    Align = EltInfo.second;
+    break;
+  }
+  case Type::Tagged:
+    RecordType *RT = dyn_cast<RecordType>(cast<TagType>(T));
+    if (!RT)
+      // FIXME: Handle enums.
+      assert(0 && "Unimplemented type sizes!");
+    const RecordLayout &Layout = getRecordLayout(RT->getDecl(), L);
+    Size = Layout.getSize();
+    Align = Layout.getAlignment();
+    break;
+  }
+  
+  assert(Align && (Align & (Align-1)) == 0 && "Alignment must be power of 2");
+  return std::make_pair(Size, Align);
+}
+
+/// getRecordLayout - Get or compute information about the layout of the
+/// specified record (struct/union/class), which indicates its size and field
+/// position information.
+const RecordLayout &ASTContext::getRecordLayout(const RecordDecl *D,
+                                                SourceLocation L) {
+  assert(D->isDefinition() && "Cannot get layout of forward declarations!");
+  
+  // Look up this layout, if already laid out, return what we have.
+  const RecordLayout *&Entry = RecordLayoutInfo[D];
+  if (Entry) return *Entry;
+  
+  // Allocate and assign into RecordLayoutInfo here.  The "Entry" reference can
+  // be invalidated (dangle) if the RecordLayoutInfo hashtable is inserted into.
+  RecordLayout *NewEntry = new RecordLayout();
+  Entry = NewEntry;
+  
+  uint64_t *FieldOffsets = new uint64_t[D->getNumMembers()];
+  uint64_t RecordSize = 0;
+  unsigned RecordAlign = 8;  // Default alignment = 1 byte = 8 bits.
+
+  if (D->getKind() != Decl::Union) {
+    // Layout each field, for now, just sequentially, respecting alignment.  In
+    // the future, this will need to be tweakable by targets.
+    for (unsigned i = 0, e = D->getNumMembers(); i != e; ++i) {
+      const FieldDecl *FD = D->getMember(i);
+      std::pair<uint64_t, unsigned> FieldInfo = getTypeInfo(FD->getType(), L);
+      uint64_t FieldSize = FieldInfo.first;
+      unsigned FieldAlign = FieldInfo.second;
+      
+      // Round up the current record size to the field's alignment boundary.
+      RecordSize = (RecordSize+FieldAlign-1) & ~(FieldAlign-1);
+      
+      // Place this field at the current location.
+      FieldOffsets[i] = RecordSize;
+      
+      // Reserve space for this field.
+      RecordSize += FieldSize;
+      
+      // Remember max struct/class alignment.
+      RecordAlign = std::max(RecordAlign, FieldAlign);
+    }
+    
+    // Finally, round the size of the total struct up to the alignment of the
+    // struct itself.
+    RecordSize = (RecordSize+RecordAlign-1) & ~(RecordAlign-1);
+  } else {
+    // Union layout just puts each member at the start of the record.
+    for (unsigned i = 0, e = D->getNumMembers(); i != e; ++i) {
+      const FieldDecl *FD = D->getMember(i);
+      std::pair<uint64_t, unsigned> FieldInfo = getTypeInfo(FD->getType(), L);
+      uint64_t FieldSize = FieldInfo.first;
+      unsigned FieldAlign = FieldInfo.second;
+      
+      // Round up the current record size to the field's alignment boundary.
+      RecordSize = std::max(RecordSize, FieldSize);
+      
+      // Place this field at the start of the record.
+      FieldOffsets[i] = 0;
+      
+      // Remember max struct/class alignment.
+      RecordAlign = std::max(RecordAlign, FieldAlign);
+    }
+  }
+  
+  NewEntry->SetLayout(RecordSize, RecordAlign, FieldOffsets);
+  return *NewEntry;
+}
+
+
+//===----------------------------------------------------------------------===//
+//                   Type creation/memoization methods
+//===----------------------------------------------------------------------===//
+
+
+/// getComplexType - Return the uniqued reference to the type for a complex
+/// number with the specified element type.
+QualType ASTContext::getComplexType(QualType T) {
+  // Unique pointers, to guarantee there is only one pointer of a particular
+  // structure.
+  llvm::FoldingSetNodeID ID;
+  ComplexType::Profile(ID, T);
+  
+  void *InsertPos = 0;
+  if (ComplexType *CT = ComplexTypes.FindNodeOrInsertPos(ID, InsertPos))
+    return QualType(CT, 0);
+  
+  // If the pointee type isn't canonical, this won't be a canonical type either,
+  // so fill in the canonical type field.
+  QualType Canonical;
+  if (!T->isCanonical()) {
+    Canonical = getComplexType(T.getCanonicalType());
+    
+    // Get the new insert position for the node we care about.
+    ComplexType *NewIP = ComplexTypes.FindNodeOrInsertPos(ID, InsertPos);
+    assert(NewIP == 0 && "Shouldn't be in the map!");
+  }
+  ComplexType *New = new ComplexType(T, Canonical);
+  Types.push_back(New);
+  ComplexTypes.InsertNode(New, InsertPos);
+  return QualType(New, 0);
+}
+
+
+/// getPointerType - Return the uniqued reference to the type for a pointer to
+/// the specified type.
+QualType ASTContext::getPointerType(QualType T) {
+  // Unique pointers, to guarantee there is only one pointer of a particular
+  // structure.
+  llvm::FoldingSetNodeID ID;
+  PointerType::Profile(ID, T);
+  
+  void *InsertPos = 0;
+  if (PointerType *PT = PointerTypes.FindNodeOrInsertPos(ID, InsertPos))
+    return QualType(PT, 0);
+  
+  // If the pointee type isn't canonical, this won't be a canonical type either,
+  // so fill in the canonical type field.
+  QualType Canonical;
+  if (!T->isCanonical()) {
+    Canonical = getPointerType(T.getCanonicalType());
+   
+    // Get the new insert position for the node we care about.
+    PointerType *NewIP = PointerTypes.FindNodeOrInsertPos(ID, InsertPos);
+    assert(NewIP == 0 && "Shouldn't be in the map!");
+  }
+  PointerType *New = new PointerType(T, Canonical);
+  Types.push_back(New);
+  PointerTypes.InsertNode(New, InsertPos);
+  return QualType(New, 0);
+}
+
+/// getReferenceType - Return the uniqued reference to the type for a reference
+/// to the specified type.
+QualType ASTContext::getReferenceType(QualType T) {
+  // Unique pointers, to guarantee there is only one pointer of a particular
+  // structure.
+  llvm::FoldingSetNodeID ID;
+  ReferenceType::Profile(ID, T);
+
+  void *InsertPos = 0;
+  if (ReferenceType *RT = ReferenceTypes.FindNodeOrInsertPos(ID, InsertPos))
+    return QualType(RT, 0);
+  
+  // If the referencee type isn't canonical, this won't be a canonical type
+  // either, so fill in the canonical type field.
+  QualType Canonical;
+  if (!T->isCanonical()) {
+    Canonical = getReferenceType(T.getCanonicalType());
+   
+    // Get the new insert position for the node we care about.
+    ReferenceType *NewIP = ReferenceTypes.FindNodeOrInsertPos(ID, InsertPos);
+    assert(NewIP == 0 && "Shouldn't be in the map!");
+  }
+
+  ReferenceType *New = new ReferenceType(T, Canonical);
+  Types.push_back(New);
+  ReferenceTypes.InsertNode(New, InsertPos);
+  return QualType(New, 0);
+}
+
+/// getArrayType - Return the unique reference to the type for an array of the
+/// specified element type.
+QualType ASTContext::getArrayType(QualType EltTy,ArrayType::ArraySizeModifier ASM,
+                                  unsigned EltTypeQuals, Expr *NumElts) {
+  // Unique array types, to guarantee there is only one array of a particular
+  // structure.
+  llvm::FoldingSetNodeID ID;
+  ArrayType::Profile(ID, ASM, EltTypeQuals, EltTy, NumElts);
+      
+  void *InsertPos = 0;
+  if (ArrayType *ATP = ArrayTypes.FindNodeOrInsertPos(ID, InsertPos))
+    return QualType(ATP, 0);
+  
+  // If the element type isn't canonical, this won't be a canonical type either,
+  // so fill in the canonical type field.
+  QualType Canonical;
+  if (!EltTy->isCanonical()) {
+    Canonical = getArrayType(EltTy.getCanonicalType(), ASM, EltTypeQuals,
+                             NumElts);
+    
+    // Get the new insert position for the node we care about.
+    ArrayType *NewIP = ArrayTypes.FindNodeOrInsertPos(ID, InsertPos);
+    assert(NewIP == 0 && "Shouldn't be in the map!");
+  }
+  
+  ArrayType *New = new ArrayType(EltTy, ASM, EltTypeQuals, Canonical, NumElts);
+  ArrayTypes.InsertNode(New, InsertPos);
+  Types.push_back(New);
+  return QualType(New, 0);
+}
+
+/// getVectorType - Return the unique reference to a vector type of
+/// the specified element type and size. VectorType must be a built-in type.
+QualType ASTContext::getVectorType(QualType vecType, unsigned NumElts) {
+  BuiltinType *baseType;
+  
+  baseType = dyn_cast<BuiltinType>(vecType.getCanonicalType().getTypePtr());
+  assert(baseType != 0 && "getVectorType(): Expecting a built-in type");
+         
+  // Check if we've already instantiated a vector of this type.
+  llvm::FoldingSetNodeID ID;
+  VectorType::Profile(ID, vecType, NumElts, Type::Vector);      
+  void *InsertPos = 0;
+  if (VectorType *VTP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos))
+    return QualType(VTP, 0);
+
+  // If the element type isn't canonical, this won't be a canonical type either,
+  // so fill in the canonical type field.
+  QualType Canonical;
+  if (!vecType->isCanonical()) {
+    Canonical = getVectorType(vecType.getCanonicalType(), NumElts);
+    
+    // Get the new insert position for the node we care about.
+    VectorType *NewIP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos);
+    assert(NewIP == 0 && "Shouldn't be in the map!");
+  }
+  VectorType *New = new VectorType(vecType, NumElts, Canonical);
+  VectorTypes.InsertNode(New, InsertPos);
+  Types.push_back(New);
+  return QualType(New, 0);
+}
+
+/// getOCUVectorType - Return the unique reference to an OCU vector type of
+/// the specified element type and size. VectorType must be a built-in type.
+QualType ASTContext::getOCUVectorType(QualType vecType, unsigned NumElts) {
+  BuiltinType *baseType;
+  
+  baseType = dyn_cast<BuiltinType>(vecType.getCanonicalType().getTypePtr());
+  assert(baseType != 0 && "getOCUVectorType(): Expecting a built-in type");
+         
+  // Check if we've already instantiated a vector of this type.
+  llvm::FoldingSetNodeID ID;
+  VectorType::Profile(ID, vecType, NumElts, Type::OCUVector);      
+  void *InsertPos = 0;
+  if (VectorType *VTP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos))
+    return QualType(VTP, 0);
+
+  // If the element type isn't canonical, this won't be a canonical type either,
+  // so fill in the canonical type field.
+  QualType Canonical;
+  if (!vecType->isCanonical()) {
+    Canonical = getOCUVectorType(vecType.getCanonicalType(), NumElts);
+    
+    // Get the new insert position for the node we care about.
+    VectorType *NewIP = VectorTypes.FindNodeOrInsertPos(ID, InsertPos);
+    assert(NewIP == 0 && "Shouldn't be in the map!");
+  }
+  OCUVectorType *New = new OCUVectorType(vecType, NumElts, Canonical);
+  VectorTypes.InsertNode(New, InsertPos);
+  Types.push_back(New);
+  return QualType(New, 0);
+}
+
+/// getFunctionTypeNoProto - Return a K&R style C function type like 'int()'.
+///
+QualType ASTContext::getFunctionTypeNoProto(QualType ResultTy) {
+  // Unique functions, to guarantee there is only one function of a particular
+  // structure.
+  llvm::FoldingSetNodeID ID;
+  FunctionTypeNoProto::Profile(ID, ResultTy);
+  
+  void *InsertPos = 0;
+  if (FunctionTypeNoProto *FT = 
+        FunctionTypeNoProtos.FindNodeOrInsertPos(ID, InsertPos))
+    return QualType(FT, 0);
+  
+  QualType Canonical;
+  if (!ResultTy->isCanonical()) {
+    Canonical = getFunctionTypeNoProto(ResultTy.getCanonicalType());
+    
+    // Get the new insert position for the node we care about.
+    FunctionTypeNoProto *NewIP =
+      FunctionTypeNoProtos.FindNodeOrInsertPos(ID, InsertPos);
+    assert(NewIP == 0 && "Shouldn't be in the map!");
+  }
+  
+  FunctionTypeNoProto *New = new FunctionTypeNoProto(ResultTy, Canonical);
+  Types.push_back(New);
+  FunctionTypeProtos.InsertNode(New, InsertPos);
+  return QualType(New, 0);
+}
+
+/// getFunctionType - Return a normal function type with a typed argument
+/// list.  isVariadic indicates whether the argument list includes '...'.
+QualType ASTContext::getFunctionType(QualType ResultTy, QualType *ArgArray,
+                                     unsigned NumArgs, bool isVariadic) {
+  // Unique functions, to guarantee there is only one function of a particular
+  // structure.
+  llvm::FoldingSetNodeID ID;
+  FunctionTypeProto::Profile(ID, ResultTy, ArgArray, NumArgs, isVariadic);
+
+  void *InsertPos = 0;
+  if (FunctionTypeProto *FTP = 
+        FunctionTypeProtos.FindNodeOrInsertPos(ID, InsertPos))
+    return QualType(FTP, 0);
+    
+  // Determine whether the type being created is already canonical or not.  
+  bool isCanonical = ResultTy->isCanonical();
+  for (unsigned i = 0; i != NumArgs && isCanonical; ++i)
+    if (!ArgArray[i]->isCanonical())
+      isCanonical = false;
+
+  // If this type isn't canonical, get the canonical version of it.
+  QualType Canonical;
+  if (!isCanonical) {
+    llvm::SmallVector<QualType, 16> CanonicalArgs;
+    CanonicalArgs.reserve(NumArgs);
+    for (unsigned i = 0; i != NumArgs; ++i)
+      CanonicalArgs.push_back(ArgArray[i].getCanonicalType());
+    
+    Canonical = getFunctionType(ResultTy.getCanonicalType(),
+                                &CanonicalArgs[0], NumArgs,
+                                isVariadic);
+    
+    // Get the new insert position for the node we care about.
+    FunctionTypeProto *NewIP =
+      FunctionTypeProtos.FindNodeOrInsertPos(ID, InsertPos);
+    assert(NewIP == 0 && "Shouldn't be in the map!");
+  }
+  
+  // FunctionTypeProto objects are not allocated with new because they have a
+  // variable size array (for parameter types) at the end of them.
+  FunctionTypeProto *FTP = 
+    (FunctionTypeProto*)malloc(sizeof(FunctionTypeProto) + 
+                               NumArgs*sizeof(QualType));
+  new (FTP) FunctionTypeProto(ResultTy, ArgArray, NumArgs, isVariadic,
+                              Canonical);
+  Types.push_back(FTP);
+  FunctionTypeProtos.InsertNode(FTP, InsertPos);
+  return QualType(FTP, 0);
+}
+
+/// getTypedefType - Return the unique reference to the type for the
+/// specified typename decl.
+QualType ASTContext::getTypedefType(TypedefDecl *Decl) {
+  if (Decl->TypeForDecl) return QualType(Decl->TypeForDecl, 0);
+  
+  QualType Canonical = Decl->getUnderlyingType().getCanonicalType();
+  Decl->TypeForDecl = new TypedefType(Decl, Canonical);
+  Types.push_back(Decl->TypeForDecl);
+  return QualType(Decl->TypeForDecl, 0);
+}
+
+/// getTagDeclType - Return the unique reference to the type for the
+/// specified TagDecl (struct/union/class/enum) decl.
+QualType ASTContext::getTagDeclType(TagDecl *Decl) {
+  // The decl stores the type cache.
+  if (Decl->TypeForDecl) return QualType(Decl->TypeForDecl, 0);
+  
+  Decl->TypeForDecl = new TagType(Decl, QualType());
+  Types.push_back(Decl->TypeForDecl);
+  return QualType(Decl->TypeForDecl, 0);
+}
+
+/// getSizeType - Return the unique type for "size_t" (C99 7.17), the result 
+/// of the sizeof operator (C99 6.5.3.4p4). The value is target dependent and 
+/// needs to agree with the definition in <stddef.h>. 
+QualType ASTContext::getSizeType() const {
+  // On Darwin, size_t is defined as a "long unsigned int". 
+  // FIXME: should derive from "Target".
+  return UnsignedLongTy; 
+}
+
+/// getPointerDiffType - Return the unique type for "ptrdiff_t" (ref?)
+/// defined in <stddef.h>. Pointer - pointer requires this (C99 6.5.6p9).
+QualType ASTContext::getPointerDiffType() const {
+  // On Darwin, ptrdiff_t is defined as a "int". This seems like a bug...
+  // FIXME: should derive from "Target".
+  return IntTy; 
+}
+
+/// getIntegerRank - Return an integer conversion rank (C99 6.3.1.1p1). This
+/// routine will assert if passed a built-in type that isn't an integer or enum.
+static int getIntegerRank(QualType t) {
+  if (const TagType *TT = dyn_cast<TagType>(t.getCanonicalType())) {
+    assert(TT->getDecl()->getKind() == Decl::Enum && "not an int or enum");
+    return 4;
+  }
+  
+  const BuiltinType *BT = cast<BuiltinType>(t.getCanonicalType());
+  switch (BT->getKind()) {
+  default:
+    assert(0 && "getIntegerRank(): not a built-in integer");
+  case BuiltinType::Bool:
+    return 1;
+  case BuiltinType::Char_S:
+  case BuiltinType::Char_U:
+  case BuiltinType::SChar:
+  case BuiltinType::UChar:
+    return 2;
+  case BuiltinType::Short:
+  case BuiltinType::UShort:
+    return 3;
+  case BuiltinType::Int:
+  case BuiltinType::UInt:
+    return 4;
+  case BuiltinType::Long:
+  case BuiltinType::ULong:
+    return 5;
+  case BuiltinType::LongLong:
+  case BuiltinType::ULongLong:
+    return 6;
+  }
+}
+
+/// getFloatingRank - Return a relative rank for floating point types.
+/// This routine will assert if passed a built-in type that isn't a float.
+static int getFloatingRank(QualType T) {
+  T = T.getCanonicalType();
+  if (ComplexType *CT = dyn_cast<ComplexType>(T))
+    return getFloatingRank(CT->getElementType());
+  
+  switch (cast<BuiltinType>(T)->getKind()) {
+  default:  assert(0 && "getFloatingPointRank(): not a floating type");
+  case BuiltinType::Float:      return FloatRank;
+  case BuiltinType::Double:     return DoubleRank;
+  case BuiltinType::LongDouble: return LongDoubleRank;
+  }
+}
+
+// maxComplexType - the following code handles 3 different combinations:
+// complex/complex, complex/float, float/complex. 
+// When both operands are complex, the shorter operand is converted to the 
+// type of the longer, and that is the type of the result. This corresponds 
+// to what is done when combining two real floating-point operands. 
+// The fun begins when size promotion occur across type domains. g
+// getFloatingRank & convertFloatingRankToComplexType handle this without 
+// enumerating all permutations. 
+// It also allows us to add new types without breakage.
+// From H&S 6.3.4: When one operand is complex and the other is a real
+// floating-point type, the less precise type is converted, within it's 
+// real or complex domain, to the precision of the other type. For example,
+// when combining a "long double" with a "double _Complex", the 
+// "double _Complex" is promoted to "long double _Complex".
+
+QualType ASTContext::maxComplexType(QualType lt, QualType rt) const {
+  switch (std::max(getFloatingRank(lt), getFloatingRank(rt))) {
+  default: assert(0 && "convertRankToComplex(): illegal value for rank");
+  case FloatRank:      return FloatComplexTy;
+  case DoubleRank:     return DoubleComplexTy;
+  case LongDoubleRank: return LongDoubleComplexTy;
+  }
+}
+
+// maxFloatingType - handles the simple case, both operands are floats.
+QualType ASTContext::maxFloatingType(QualType lt, QualType rt) {
+  return getFloatingRank(lt) > getFloatingRank(rt) ? lt : rt;
+}
+
+// maxIntegerType - Returns the highest ranked integer type. Handles 3 case:
+// unsigned/unsigned, signed/signed, signed/unsigned. C99 6.3.1.8p1.
+QualType ASTContext::maxIntegerType(QualType lhs, QualType rhs) {
+  if (lhs == rhs) return lhs;
+  
+  bool t1Unsigned = lhs->isUnsignedIntegerType();
+  bool t2Unsigned = rhs->isUnsignedIntegerType();
+  
+  if ((t1Unsigned && t2Unsigned) || (!t1Unsigned && !t2Unsigned))
+    return getIntegerRank(lhs) >= getIntegerRank(rhs) ? lhs : rhs; 
+  
+  // We have two integer types with differing signs
+  QualType unsignedType = t1Unsigned ? lhs : rhs;
+  QualType signedType = t1Unsigned ? rhs : lhs;
+  
+  if (getIntegerRank(unsignedType) >= getIntegerRank(signedType))
+    return unsignedType;
+  else {
+    // FIXME: Need to check if the signed type can represent all values of the 
+    // unsigned type. If it can, then the result is the signed type. 
+    // If it can't, then the result is the unsigned version of the signed type.  
+    // Should probably add a helper that returns a signed integer type from 
+    // an unsigned (and vice versa). C99 6.3.1.8.
+    return signedType; 
+  }
+}