Remove undefined behavior from parse_error().

Having function that takes arbitrary number of arguments without
actually reading them is undefined behavior, as it could cause stack
to be in the corrupted state. Now arguments after token are parsed,
even if they aren't needed.

See also: http://asciinema.org/a/5904

1 files changed, 17 insertions, 10 deletions

diff --git a/parse_tree.cpp b/parse_tree.cpp
index 97421dab..3e0c5256 100644
--- a/parse_tree.cpp
+++ b/parse_tree.cpp
@@ -341,6 +341,7 @@ class parse_ll_t
     bool top_node_handle_terminal_types(parse_token_t token);
 
     void parse_error(const wchar_t *expected, parse_token_t token);
+    void parse_error(parse_token_t token);
     void parse_error(parse_token_t token, const wchar_t *format, ...);
     void append_error_callout(wcstring &error_message, parse_token_t token);
 
@@ -551,19 +552,25 @@ void parse_ll_t::acquire_output(parse_node_tree_t *output, parse_error_list_t *e
     this->symbol_stack.clear();
 }
 
-void parse_ll_t::parse_error(parse_token_t token, const wchar_t *fmt, ...)
+void parse_ll_t::parse_error(parse_token_t token)
 {
     this->fatal_errored = true;
-    if (this->should_generate_error_messages)
-    {
-        //this->dump_stack();
-        parse_error_t err;
+}
+
+void parse_ll_t::parse_error(parse_token_t token, const wchar_t *fmt, ...)
+{
+    parse_error(token);
+
+    //this->dump_stack();
+    parse_error_t err;
 
-        va_list va;
-        va_start(va, fmt);
-        err.text = vformat_string(fmt, va);
-        va_end(va);
+    va_list va;
+    va_start(va, fmt);
+    err.text = vformat_string(fmt, va);
+    va_end(va);
 
+    if (this->should_generate_error_messages)
+    {
         err.source_start = token.source_start;
         err.source_length = token.source_length;
         this->errors.push_back(err);
@@ -730,7 +737,7 @@ void parse_ll_t::accept_tokens(parse_token_t token1, parse_token_t token2)
             }
             else
             {
-                this->parse_error(token1, NULL);
+                this->parse_error(token1);
             }
             // parse_error sets fatal_errored, which ends the loop
         }