AtomicExpr: make ASTStmtReader a friend and remove setters. Also fix saving
of an uninitialized Stmt* in serialization of __atomic_init and add a test of
atomics serialization.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@154448 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Serialization/ASTWriterStmt.cpp b/lib/Serialization/ASTWriterStmt.cpp
index eac7e1f..827caa0 100644
--- a/lib/Serialization/ASTWriterStmt.cpp
+++ b/lib/Serialization/ASTWriterStmt.cpp
@@ -751,14 +751,8 @@
 void ASTStmtWriter::VisitAtomicExpr(AtomicExpr *E) {
   VisitExpr(E);
   Record.push_back(E->getOp());
-  Writer.AddStmt(E->getPtr());
-  Writer.AddStmt(E->getOrder());
-  if (E->getOp() != AtomicExpr::Load)
-    Writer.AddStmt(E->getVal1());
-  if (E->isCmpXChg()) {
-    Writer.AddStmt(E->getOrderFail());
-    Writer.AddStmt(E->getVal2());
-  }
+  for (unsigned I = 0, N = E->getNumSubExprs(); I != N; ++I)
+    Writer.AddStmt(E->getSubExprs()[I]);
   Writer.AddSourceLocation(E->getBuiltinLoc(), Record);
   Writer.AddSourceLocation(E->getRParenLoc(), Record);
   Code = serialization::EXPR_ATOMIC;