Merge pull request #81 from undingen/iterator_invalid

Remove read from freed memory

src/core/ast.h

@@ -808,7 +808,10 @@ public:
     virtual void accept(ASTVisitor* v);
     virtual void accept_stmt(StmtVisitor* v);
 
-    AST_Jump() : AST_stmt(AST_TYPE::Jump) {}
+    AST_Jump() : AST_stmt(AST_TYPE::Jump) {
+        lineno = -1;
+        col_offset = -1;
+    }
 
     static const AST_TYPE::AST_TYPE TYPE = AST_TYPE::Jump;
 };

src/core/cfg.cpp

@@ -1654,7 +1654,10 @@ CFG* computeCFG(AST_TYPE::AST_TYPE root_type, std::vector<AST_stmt*> body) {
     // and can make the analyses more efficient.
     // The extra blocks would get merged by LLVM passes, so I'm not sure
     // how much overall improvement there is.
-    for (CFGBlock* b : rtn->blocks) {
+
+    // Must evaluate end() on every iteration because erase() will invalidate the end.
+    for (auto it = rtn->blocks.begin(); it != rtn->blocks.end(); ++it) {
+        CFGBlock* b = *it;
         while (b->successors.size() == 1) {
             CFGBlock* b2 = b->successors[0];
             if (b2->predecessors.size() != 1)