Overhaul of Stmt allocation:
- Made allocation of Stmt objects using vanilla new/delete a *compiler
  error* by making this new/delete "protected" within class Stmt.
- Now the only way to allocate Stmt objects is by using the new
  operator that takes ASTContext& as an argument.  This ensures that
  all Stmt nodes are allocated from the same (pool) allocator.
- Naturally, these two changes required that *all* creation sites for
  AST nodes use new (ASTContext&).  This is a large patch, but the
  majority of the changes are just this mechanical adjustment.
- The above changes also mean that AST nodes can no longer be
  deallocated using 'delete'.  Instead, one most do
  StmtObject->Destroy(ASTContext&) or do
  ASTContextObject.Deallocate(StmtObject) (the latter not running the
  'Destroy' method).

Along the way I also...
- Made CompoundStmt allocate its array of Stmt* using the allocator in
  ASTContext (previously it used std::vector).  There are a whole
  bunch of other Stmt classes that need to be similarly changed to
  ensure that all memory allocated for ASTs comes from the allocator
  in ASTContext.
- Added a new smart pointer ExprOwningPtr to Sema.h.  This replaces
  the uses of llvm::OwningPtr within Sema, as llvm::OwningPtr used
  'delete' to free memory instead of a Stmt's 'Destroy' method.

Big thanks to Doug Gregor for helping with the acrobatics of making
'new/delete' private and the new smart pointer ExprOwningPtr!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63997 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 92cad10..e52c730 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -306,9 +306,10 @@
     TheCall->setArg(i, 0);
   }
 
-  return Owned(new ShuffleVectorExpr(exprs.begin(), numElements+2, FAType,
-                                     TheCall->getCallee()->getLocStart(),
-                                     TheCall->getRParenLoc()));
+  return Owned(new (Context) ShuffleVectorExpr(exprs.begin(), numElements+2,
+                                            FAType,
+                                            TheCall->getCallee()->getLocStart(),
+                                            TheCall->getRParenLoc()));
 }
 
 /// SemaBuiltinPrefetch - Handle __builtin_prefetch.