From ba36180fd7b68341ad57e0fbe7a55cdfb334908d Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Thu, 2 Nov 2017 09:28:56 -0200
Subject: new API for 'lua_resume' + cleaning the uses of the 'extra' field in
 'CallInfo'

---
 ldebug.c | 25 +------------------------
 1 file changed, 1 insertion(+), 24 deletions(-)

(limited to 'ldebug.c')

diff --git a/ldebug.c b/ldebug.c
index 9b6f3bbe..5ca78bd1 100644
--- a/ldebug.c
+++ b/ldebug.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.c,v 2.133 2017/10/31 17:14:02 roberto Exp roberto $
+** $Id: ldebug.c,v 2.134 2017/11/01 18:20:48 roberto Exp roberto $
 ** Debug Interface
 ** See Copyright Notice in lua.h
 */
@@ -106,22 +106,6 @@ static int currentline (CallInfo *ci) {
 }
 
 
-/*
-** If function yielded, its 'func' can be in the 'extra' field. The
-** next function restores 'func' to its correct value for debugging
-** purposes. (It exchanges 'func' and 'extra'; so, when called again,
-** after debugging, it also "re-restores" ** 'func' to its altered value.
-*/
-static void swapextra (lua_State *L) {
-  if (L->status == LUA_YIELD) {
-    CallInfo *ci = L->ci;  /* get function that yielded */
-    StkId temp = ci->func;  /* exchange its 'func' and 'extra' values */
-    L->func = ci->func = restorestack(L, ci->extra);
-    ci->extra = savestack(L, temp);
-  }
-}
-
-
 /*
 ** This function can be called asynchronously (e.g. during a signal).
 ** Fields 'oldpc', 'basehookcount', and 'hookcount' (set by
@@ -209,7 +193,6 @@ static const char *findlocal (lua_State *L, CallInfo *ci, int n,
 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
   const char *name;
   lua_lock(L);
-  swapextra(L);
   if (ar == NULL) {  /* information about non-active function? */
     if (!isLfunction(s2v(L->top - 1)))  /* not a Lua function? */
       name = NULL;
@@ -224,7 +207,6 @@ LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
       api_incr_top(L);
     }
   }
-  swapextra(L);
   lua_unlock(L);
   return name;
 }
@@ -234,13 +216,11 @@ LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
   StkId pos = NULL;  /* to avoid warnings */
   const char *name;
   lua_lock(L);
-  swapextra(L);
   name = findlocal(L, ar->i_ci, n, &pos);
   if (name) {
     setobjs2s(L, pos, L->top - 1);
     L->top--;  /* pop value */
   }
-  swapextra(L);
   lua_unlock(L);
   return name;
 }
@@ -361,7 +341,6 @@ LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
   CallInfo *ci;
   TValue *func;
   lua_lock(L);
-  swapextra(L);
   if (*what == '>') {
     ci = NULL;
     func = s2v(L->top - 1);
@@ -380,7 +359,6 @@ LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
     setobj2s(L, L->top, func);
     api_incr_top(L);
   }
-  swapextra(L);  /* correct before option 'L', which can raise a mem. error */
   if (strchr(what, 'L'))
     collectvalidlines(L, cl);
   lua_unlock(L);
@@ -790,7 +768,6 @@ void luaG_traceexec (lua_State *L) {
       L->hookcount = 1;  /* undo decrement to zero */
     ci->u.l.savedpc--;  /* undo increment (resume will increment it again) */
     ci->callstatus |= CIST_HOOKYIELD;  /* mark that it yielded */
-    L->func = ci->func = L->top - 1;  /* protect stack below results */
     luaD_throw(L, LUA_YIELD);
   }
 }
-- 
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