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.

llvm-svn: 111455
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index ffe8f22..72ec584 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -150,11 +150,11 @@
   if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>()) {
     switch (attr->getVisibility()) {
     default: assert(0 && "Unknown visibility!");
-    case VisibilityAttr::DefaultVisibility:
+    case VisibilityAttr::Default:
       return LangOptions::Default;
-    case VisibilityAttr::HiddenVisibility:
+    case VisibilityAttr::Hidden:
       return LangOptions::Hidden;
-    case VisibilityAttr::ProtectedVisibility:
+    case VisibilityAttr::Protected:
       return LangOptions::Protected;
     }
   }
@@ -461,12 +461,10 @@
   else if (Features.getStackProtectorMode() == LangOptions::SSPReq)
     F->addFnAttr(llvm::Attribute::StackProtectReq);
   
-  if (const AlignedAttr *AA = D->getAttr<AlignedAttr>()) {
-    unsigned width = Context.Target.getCharWidth();
-    F->setAlignment(AA->getAlignment() / width);
-    while ((AA = AA->getNext<AlignedAttr>()))
-      F->setAlignment(std::max(F->getAlignment(), AA->getAlignment() / width));
-  }
+  unsigned alignment = D->getMaxAlignment() / Context.getCharWidth();
+  if (alignment)
+    F->setAlignment(alignment);
+
   // C++ ABI requires 2-byte alignment for member functions.
   if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D))
     F->setAlignment(2);