Generate Attr subclasses with TableGen.

Now all classes derived from Attr are generated from TableGen.
Additionally, Attr* is no longer its own linked list; SmallVectors or
Attr* are used. The accompanying LLVM commit contains the updates to
TableGen necessary for this.

Some other notes about newly-generated attribute classes:

 - The constructor arguments are a SourceLocation and a Context&,
   followed by the attributes arguments in the order that they were
   defined in Attr.td

 - Every argument in Attr.td has an appropriate accessor named getFoo,
   and there are sometimes a few extra ones (such as to get the length
   of a variadic argument).

Additionally, specific_attr_iterator has been introduced, which will
iterate over an AttrVec, but only over attributes of a certain type. It
can be accessed through either Decl::specific_attr_begin/end or
the global functions of the same name.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@111455 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index b549415..f53a50e 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -497,8 +497,7 @@
 CharUnits ASTContext::getDeclAlign(const Decl *D, bool RefAsPointee) {
   unsigned Align = Target.getCharWidth();
 
-  if (const AlignedAttr* AA = D->getAttr<AlignedAttr>())
-    Align = std::max(Align, AA->getMaxAlignment());
+  Align = std::max(Align, D->getMaxAlignment());
 
   if (const ValueDecl *VD = dyn_cast<ValueDecl>(D)) {
     QualType T = VD->getType();
@@ -760,12 +759,9 @@
 
   case Type::Typedef: {
     const TypedefDecl *Typedef = cast<TypedefType>(T)->getDecl();
-    if (const AlignedAttr *Aligned = Typedef->getAttr<AlignedAttr>()) {
-      Align = std::max(Aligned->getMaxAlignment(),
-                       getTypeAlign(Typedef->getUnderlyingType().getTypePtr()));
-      Width = getTypeSize(Typedef->getUnderlyingType().getTypePtr());
-    } else
-      return getTypeInfo(Typedef->getUnderlyingType().getTypePtr());
+    Align = std::max(Typedef->getMaxAlignment(),
+                     getTypeAlign(Typedef->getUnderlyingType().getTypePtr()));
+    Width = getTypeSize(Typedef->getUnderlyingType().getTypePtr());
     break;
   }