1 files changed, 51 insertions, 0 deletions

diff --git a/src/lj_debug.c b/src/lj_debug.c
index 0e26cd7c..4f4c4bb1 100644
--- a/src/lj_debug.c
+++ b/src/lj_debug.c
@@ -543,3 +543,54 @@ LUA_API int lua_getstack(lua_State *L, int level, lua_Debug *ar)
   }
 }
 
+/* Number of frames for the leading and trailing part of a traceback. */
+#define TRACEBACK_LEVELS1       12
+#define TRACEBACK_LEVELS2       10
+
+LUALIB_API void luaL_traceback (lua_State *L, lua_State *L1, const char *msg,
+                                int level)
+{
+  int top = (int)(L->top - L->base);
+  int lim = TRACEBACK_LEVELS1;
+  lua_Debug ar;
+  if (msg) lua_pushfstring(L, "%s\n", msg);
+  lua_pushliteral(L, "stack traceback:");
+  while (lua_getstack(L1, level++, &ar)) {
+    GCfunc *fn;
+    if (level > lim) {
+      if (!lua_getstack(L1, level + TRACEBACK_LEVELS2, &ar)) {
+        level--;
+      } else {
+        lua_pushliteral(L, "\n\t...");
+        lua_getstack(L1, -10, &ar);
+        level = ar.i_ci - TRACEBACK_LEVELS2;
+      }
+      lim = 2147483647;
+      continue;
+    }
+    lua_getinfo(L1, "Snlf", &ar);
+    fn = funcV(L1->top-1); L1->top--;
+    if (isffunc(fn) && !*ar.namewhat)
+      lua_pushfstring(L, "\n\t[builtin#%d]:", fn->c.ffid);
+    else
+      lua_pushfstring(L, "\n\t%s:", ar.short_src);
+    if (ar.currentline > 0)
+      lua_pushfstring(L, "%d:", ar.currentline);
+    if (*ar.namewhat) {
+      lua_pushfstring(L, " in function " LUA_QS, ar.name);
+    } else {
+      if (*ar.what == 'm') {
+        lua_pushliteral(L, " in main chunk");
+      } else if (*ar.what == 'C') {
+        lua_pushfstring(L, " at %p", fn->c.f);
+      } else {
+        lua_pushfstring(L, " in function <%s:%d>",
+                        ar.short_src, ar.linedefined);
+      }
+    }
+    if ((int)(L->top - L->base) - top >= 15)
+      lua_concat(L, (int)(L->top - L->base) - top);
+  }
+  lua_concat(L, (int)(L->top - L->base) - top);
+}
+