[AST] Assert that no statement/expression class is polymorphic

Add a static_assert checking that no statement/expression class
is polymorphic. People should use LLVM style RTTI instead.

Differential Revision: https://reviews.llvm.org/D55222

Reviewed By: aaron.ballman

llvm-svn: 348278

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/lib/AST/Stmt.cpp b/clang/lib/AST/Stmt.cpp
index 32330ea..116291b 100644
--- a/clang/lib/AST/Stmt.cpp
+++ b/clang/lib/AST/Stmt.cpp
@@ -76,6 +76,14 @@ const char *Stmt::getStmtClassName() const {
   return getStmtInfoTableEntry((StmtClass) StmtBits.sClass).Name;
 }
 
+// Check that no statement / expression class is polymorphic. LLVM style RTTI
+// should be used instead. If absolutely needed an exception can still be added
+// here by defining the appropriate macro (but please don't do this).
+#define STMT(CLASS, PARENT) \
+  static_assert(!std::is_polymorphic<CLASS>::value, \
+                #CLASS " should not be polymorphic!");
+#include "clang/AST/StmtNodes.inc"
+
 void Stmt::PrintStats() {
   // Ensure the table is primed.
   getStmtInfoTableEntry(Stmt::NullStmtClass);