Add an AdjustedType sugar node for adjusting calling conventions

Summary:
In general, this type node can be used to represent any type adjustment
that occurs implicitly without losing type sugar.  The immediate use of
this is to adjust the calling conventions of member function pointer
types without breaking template instantiation.

Fixes PR17996.

Reviewers: rsmith

Differential Revision: http://llvm-reviews.chandlerc.com/D2332

llvm-svn: 196451

1 files changed, 36 insertions, 14 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 0528a58f894..79b8770e0b7 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -1632,8 +1632,9 @@ ASTContext::getTypeInfoImpl(const Type *T) const {
   }
   case Type::ObjCObject:
     return getTypeInfo(cast<ObjCObjectType>(T)->getBaseType().getTypePtr());
+  case Type::Adjusted:
   case Type::Decayed:
-    return getTypeInfo(cast<DecayedType>(T)->getDecayedType().getTypePtr());
+    return getTypeInfo(cast<AdjustedType>(T)->getAdjustedType().getTypePtr());
   case Type::ObjCInterface: {
     const ObjCInterfaceType *ObjCI = cast<ObjCInterfaceType>(T);
     const ASTRecordLayout &Layout = getASTObjCInterfaceLayout(ObjCI->getDecl());
@@ -2163,14 +2164,29 @@ QualType ASTContext::getPointerType(QualType T) const {
   return QualType(New, 0);
 }
 
-QualType ASTContext::getDecayedType(QualType T) const {
-  assert((T->isArrayType() || T->isFunctionType()) && "T does not decay");
-
+QualType ASTContext::getAdjustedType(QualType Orig, QualType New) const {
   llvm::FoldingSetNodeID ID;
-  DecayedType::Profile(ID, T);
+  AdjustedType::Profile(ID, Orig, New);
   void *InsertPos = 0;
-  if (DecayedType *DT = DecayedTypes.FindNodeOrInsertPos(ID, InsertPos))
-    return QualType(DT, 0);
+  AdjustedType *AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
+  if (AT)
+    return QualType(AT, 0);
+
+  QualType Canonical = getCanonicalType(New);
+
+  // Get the new insert position for the node we care about.
+  AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
+  assert(AT == 0 && "Shouldn't be in the map!");
+
+  AT = new (*this, TypeAlignment)
+      AdjustedType(Type::Adjusted, Orig, New, Canonical);
+  Types.push_back(AT);
+  AdjustedTypes.InsertNode(AT, InsertPos);
+  return QualType(AT, 0);
+}
+
+QualType ASTContext::getDecayedType(QualType T) const {
+  assert((T->isArrayType() || T->isFunctionType()) && "T does not decay");
 
   QualType Decayed;
 
@@ -2189,17 +2205,23 @@ QualType ASTContext::getDecayedType(QualType T) const {
   if (T->isFunctionType())
     Decayed = getPointerType(T);
 
+  llvm::FoldingSetNodeID ID;
+  AdjustedType::Profile(ID, T, Decayed);
+  void *InsertPos = 0;
+  AdjustedType *AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
+  if (AT)
+    return QualType(AT, 0);
+
   QualType Canonical = getCanonicalType(Decayed);
 
   // Get the new insert position for the node we care about.
-  DecayedType *NewIP = DecayedTypes.FindNodeOrInsertPos(ID, InsertPos);
-  assert(NewIP == 0 && "Shouldn't be in the map!"); (void)NewIP;
+  AT = AdjustedTypes.FindNodeOrInsertPos(ID, InsertPos);
+  assert(AT == 0 && "Shouldn't be in the map!");
 
-  DecayedType *New =
-      new (*this, TypeAlignment) DecayedType(T, Decayed, Canonical);
-  Types.push_back(New);
-  DecayedTypes.InsertNode(New, InsertPos);
-  return QualType(New, 0);
+  AT = new (*this, TypeAlignment) DecayedType(T, Decayed, Canonical);
+  Types.push_back(AT);
+  AdjustedTypes.InsertNode(AT, InsertPos);
+  return QualType(AT, 0);
 }
 
 /// getBlockPointerType - Return the uniqued reference to the type for