7 files changed, 62 insertions, 36 deletions

diff --git a/src/lua/lapi.c b/src/lua/lapi.c
index a9cf2fd..f8f70cd 100644
--- a/src/lua/lapi.c
+++ b/src/lua/lapi.c
@@ -173,7 +173,7 @@ LUA_API int lua_gettop (lua_State *L) {
 
 LUA_API void lua_settop (lua_State *L, int idx) {
   CallInfo *ci;
-  StkId func;
+  StkId func, newtop;
   ptrdiff_t diff;  /* difference for new top */
   lua_lock(L);
   ci = L->ci;
@@ -188,12 +188,13 @@ LUA_API void lua_settop (lua_State *L, int idx) {
     api_check(L, -(idx+1) <= (L->top - (func + 1)), "invalid new top");
     diff = idx + 1;  /* will "subtract" index (as it is negative) */
   }
-#if defined(LUA_COMPAT_5_4_0)
-  if (diff < 0 && hastocloseCfunc(ci->nresults))
-    luaF_close(L, L->top + diff, CLOSEKTOP, 0);
-#endif
-  api_check(L, L->tbclist < L->top + diff, "cannot pop an unclosed slot");
-  L->top += diff;
+  api_check(L, L->tbclist < L->top, "previous pop of an unclosed slot");
+  newtop = L->top + diff;
+  if (diff < 0 && L->tbclist >= newtop) {
+    lua_assert(hastocloseCfunc(ci->nresults));
+    luaF_close(L, newtop, CLOSEKTOP, 0);
+  }
+  L->top = newtop;  /* correct top only after closing any upvalue */
   lua_unlock(L);
 }
 
diff --git a/src/lua/lauxlib.h b/src/lua/lauxlib.h
index 9058e26..72f70e7 100644
--- a/src/lua/lauxlib.h
+++ b/src/lua/lauxlib.h
@@ -12,6 +12,7 @@
 #include <stddef.h>
 #include <stdio.h>
 
+#include "luaconf.h"
 #include "lua.h"
 
 
@@ -122,10 +123,6 @@ LUALIB_API void (luaL_requiref) (lua_State *L, const char *modname,
 ** ===============================================================
 */
 
-#if !defined(l_likely)
-#define l_likely(x)     x
-#endif
-
 
 #define luaL_newlibtable(L,l)   \
   lua_createtable(L, 0, sizeof(l)/sizeof((l)[0]) - 1)
@@ -134,10 +131,10 @@ LUALIB_API void (luaL_requiref) (lua_State *L, const char *modname,
   (luaL_checkversion(L), luaL_newlibtable(L,l), luaL_setfuncs(L,l,0))
 
 #define luaL_argcheck(L, cond,arg,extramsg)     \
-        ((void)(l_likely(cond) || luaL_argerror(L, (arg), (extramsg))))
+        ((void)(luai_likely(cond) || luaL_argerror(L, (arg), (extramsg))))
 
 #define luaL_argexpected(L,cond,arg,tname)      \
-        ((void)(l_likely(cond) || luaL_typeerror(L, (arg), (tname))))
+        ((void)(luai_likely(cond) || luaL_typeerror(L, (arg), (tname))))
 
 #define luaL_checkstring(L,n)   (luaL_checklstring(L, (n), NULL))
 #define luaL_optstring(L,n,d)   (luaL_optlstring(L, (n), (d), NULL))
diff --git a/src/lua/ldebug.c b/src/lua/ldebug.c
index 8e3657a..1feaab2 100644
--- a/src/lua/ldebug.c
+++ b/src/lua/ldebug.c
@@ -50,6 +50,8 @@ static int currentpc (CallInfo *ci) {
 ** an integer division gets the right place. When the source file has
 ** large sequences of empty/comment lines, it may need extra entries,
 ** so the original estimate needs a correction.
+** If the original estimate is -1, the initial 'if' ensures that the
+** 'while' will run at least once.
 ** The assertion that the estimate is a lower bound for the correct base
 ** is valid as long as the debug info has been generated with the same
 ** value for MAXIWTHABS or smaller. (Previous releases use a little
@@ -63,7 +65,8 @@ static int getbaseline (const Proto *f, int pc, int *basepc) {
   else {
     int i = cast_uint(pc) / MAXIWTHABS - 1;  /* get an estimate */
     /* estimate must be a lower bond of the correct base */
-    lua_assert(i < f->sizeabslineinfo && f->abslineinfo[i].pc <= pc);
+    lua_assert(i < 0 ||
+              (i < f->sizeabslineinfo && f->abslineinfo[i].pc <= pc));
     while (i + 1 < f->sizeabslineinfo && pc >= f->abslineinfo[i + 1].pc)
       i++;  /* low estimate; adjust it */
     *basepc = f->abslineinfo[i].pc;
diff --git a/src/lua/lfunc.c b/src/lua/lfunc.c
index b4c04bd..f5889a2 100644
--- a/src/lua/lfunc.c
+++ b/src/lua/lfunc.c
@@ -155,6 +155,15 @@ static void prepcallclosemth (lua_State *L, StkId level, int status, int yy) {
 
 
 /*
+** Maximum value for deltas in 'tbclist', dependent on the type
+** of delta. (This macro assumes that an 'L' is in scope where it
+** is used.)
+*/
+#define MAXDELTA  \
+        ((256ul << ((sizeof(L->stack->tbclist.delta) - 1) * 8)) - 1)
+
+
+/*
 ** Insert a variable in the list of to-be-closed variables.
 */
 void luaF_newtbcupval (lua_State *L, StkId level) {
@@ -162,13 +171,11 @@ void luaF_newtbcupval (lua_State *L, StkId level) {
   if (l_isfalse(s2v(level)))
     return;  /* false doesn't need to be closed */
   checkclosemth(L, level);  /* value must have a close method */
-  while (level - L->tbclist > USHRT_MAX) {  /* is delta too large? */
-    L->tbclist += USHRT_MAX;  /* create a dummy node at maximum delta */
-    L->tbclist->tbclist.delta = USHRT_MAX;
-    L->tbclist->tbclist.isdummy = 1;
+  while (cast_uint(level - L->tbclist) > MAXDELTA) {
+    L->tbclist += MAXDELTA;  /* create a dummy node at maximum delta */
+    L->tbclist->tbclist.delta = 0;
   }
-  level->tbclist.delta = level - L->tbclist;
-  level->tbclist.isdummy = 0;
+  level->tbclist.delta = cast(unsigned short, level - L->tbclist);
   L->tbclist = level;
 }
 
@@ -202,6 +209,19 @@ void luaF_closeupval (lua_State *L, StkId level) {
 
 
 /*
+** Remove firt element from the tbclist plus its dummy nodes.
+*/
+static void poptbclist (lua_State *L) {
+  StkId tbc = L->tbclist;
+  lua_assert(tbc->tbclist.delta > 0);  /* first element cannot be dummy */
+  tbc -= tbc->tbclist.delta;
+  while (tbc > L->stack && tbc->tbclist.delta == 0)
+    tbc -= MAXDELTA;  /* remove dummy nodes */
+  L->tbclist = tbc;
+}
+
+
+/*
 ** Close all upvalues and to-be-closed variables up to the given stack
 ** level.
 */
@@ -210,11 +230,9 @@ void luaF_close (lua_State *L, StkId level, int status, int yy) {
   luaF_closeupval(L, level);  /* first, close the upvalues */
   while (L->tbclist >= level) {  /* traverse tbc's down to that level */
     StkId tbc = L->tbclist;  /* get variable index */
-    L->tbclist -= tbc->tbclist.delta;  /* remove it from list */
-    if (!tbc->tbclist.isdummy) {  /* not a dummy entry? */
-      prepcallclosemth(L, tbc, status, yy);  /* close variable */
-      level = restorestack(L, levelrel);
-    }
+    poptbclist(L);  /* remove it from list */
+    prepcallclosemth(L, tbc, status, yy);  /* close variable */
+    level = restorestack(L, levelrel);
   }
 }
 
diff --git a/src/lua/lobject.h b/src/lua/lobject.h
index 1a7a737..950bebb 100644
--- a/src/lua/lobject.h
+++ b/src/lua/lobject.h
@@ -139,13 +139,14 @@ typedef struct TValue {
 ** Entries in a Lua stack. Field 'tbclist' forms a list of all
 ** to-be-closed variables active in this stack. Dummy entries are
 ** used when the distance between two tbc variables does not fit
-** in an unsigned short.
+** in an unsigned short. They are represented by delta==0, and
+** their real delta is always the maximum value that fits in
+** that field.
 */
 typedef union StackValue {
   TValue val;
   struct {
     TValuefields;
-    lu_byte isdummy;
     unsigned short delta;
   } tbclist;
 } StackValue;
diff --git a/src/lua/lua.h b/src/lua/lua.h
index aec70da..820535b 100644
--- a/src/lua/lua.h
+++ b/src/lua/lua.h
@@ -18,14 +18,14 @@
 
 #define LUA_VERSION_MAJOR       "5"
 #define LUA_VERSION_MINOR       "4"
-#define LUA_VERSION_RELEASE     "2"
+#define LUA_VERSION_RELEASE     "3"
 
 #define LUA_VERSION_NUM                 504
 #define LUA_VERSION_RELEASE_NUM         (LUA_VERSION_NUM * 100 + 0)
 
 #define LUA_VERSION     "Lua " LUA_VERSION_MAJOR "." LUA_VERSION_MINOR
 #define LUA_RELEASE     LUA_VERSION "." LUA_VERSION_RELEASE
-#define LUA_COPYRIGHT   LUA_RELEASE "  Copyright (C) 1994-2020 Lua.org, PUC-Rio"
+#define LUA_COPYRIGHT   LUA_RELEASE "  Copyright (C) 1994-2021 Lua.org, PUC-Rio"
 #define LUA_AUTHORS     "R. Ierusalimschy, L. H. de Figueiredo, W. Celes"
 
 
@@ -492,7 +492,7 @@ struct lua_Debug {
 
 
 /******************************************************************************
-* Copyright (C) 1994-2020 Lua.org, PUC-Rio.
+* Copyright (C) 1994-2021 Lua.org, PUC-Rio.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
diff --git a/src/lua/luaconf.h b/src/lua/luaconf.h
index ae73e2f..38e14ed 100644
--- a/src/lua/luaconf.h
+++ b/src/lua/luaconf.h
@@ -665,20 +665,26 @@
 ** macros to improve jump prediction, used mostly for error handling
 ** and debug facilities.
 */
-#if (defined(LUA_CORE) || defined(LUA_LIB)) && !defined(l_likely)
+#if !defined(luai_likely)
 
-#include <stdio.h>
 #if defined(__GNUC__)
-#define l_likely(x)     (__builtin_expect(((x) != 0), 1))
-#define l_unlikely(x)   (__builtin_expect(((x) != 0), 0))
+#define luai_likely(x)          (__builtin_expect(((x) != 0), 1))
+#define luai_unlikely(x)        (__builtin_expect(((x) != 0), 0))
 #else
-#define l_likely(x)     (x)
-#define l_unlikely(x)   (x)
+#define luai_likely(x)          (x)
+#define luai_unlikely(x)        (x)
 #endif
 
 #endif
 
 
+#if defined(LUA_CORE) || defined(LUA_LIB)
+/* shorter names for Lua's own use */
+#define l_likely(x)     luai_likely(x)
+#define l_unlikely(x)   luai_unlikely(x)
+#endif
+
+
 
 /* }================================================================== */