1 files changed, 12 insertions, 1 deletions
diff --git a/examples/Kaleidoscope/Chapter2/toy.cpp b/examples/Kaleidoscope/Chapter2/toy.cpp
index 2dc6711..99ec90e 100644
--- a/examples/Kaleidoscope/Chapter2/toy.cpp
+++ b/examples/Kaleidoscope/Chapter2/toy.cpp
@@ -79,13 +79,14 @@ static int gettok() {
 /// ExprAST - Base class for all expression nodes.
 class ExprAST {
 public:
-  virtual ~ExprAST() {}
+  virtual ~ExprAST();
 };
 
 /// NumberExprAST - Expression class for numeric literals like "1.0".
 class NumberExprAST : public ExprAST {
 public:
   NumberExprAST(double val) {}
+  virtual ~NumberExprAST();
 };
 
 /// VariableExprAST - Expression class for referencing a variable, like "a".
@@ -93,12 +94,14 @@ class VariableExprAST : public ExprAST {
   std::string Name;
 public:
   VariableExprAST(const std::string &name) : Name(name) {}
+  virtual ~VariableExprAST();
 };
 
 /// BinaryExprAST - Expression class for a binary operator.
 class BinaryExprAST : public ExprAST {
 public:
   BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs) {}
+  virtual ~BinaryExprAST();
 };
 
 /// CallExprAST - Expression class for function calls.
@@ -108,8 +111,16 @@ class CallExprAST : public ExprAST {
 public:
   CallExprAST(const std::string &callee, std::vector<ExprAST*> &args)
     : Callee(callee), Args(args) {}
+  virtual ~CallExprAST();
 };
 
+// Provide out-of-line definitions to prevent weak vtables.
+ExprAST::~ExprAST() {}
+NumberExprAST::~NumberExprAST() {}
+VariableExprAST::~VariableExprAST() {}
+BinaryExprAST::~BinaryExprAST() {}
+CallExprAST::~CallExprAST() {}
+
 /// PrototypeAST - This class represents the "prototype" for a function,
 /// which captures its name, and its argument names (thus implicitly the number
 /// of arguments the function takes).