From 196c87c9cecfacf978f37de4ec69eba0a5971256 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Thu, 23 Nov 2017 14:41:16 -0200
Subject: no more 'stackless' implementation; 'luaV_execute' calls itself
recursively to execute function calls. 'unroll' continues all executions
suspended by an yield (through a long jump)
---
ldo.c | 66 ++++++++++++++++++------------------------------------------------
1 file changed, 18 insertions(+), 48 deletions(-)
(limited to 'ldo.c')
diff --git a/ldo.c b/ldo.c
index 30954123..6b8162d2 100644
--- a/ldo.c
+++ b/ldo.c
@@ -1,5 +1,5 @@
/*
-** $Id: ldo.c,v 2.172 2017/11/13 15:36:52 roberto Exp roberto $
+** $Id: ldo.c,v 2.173 2017/11/21 14:17:35 roberto Exp roberto $
** Stack and Call structure of Lua
** See Copyright Notice in lua.h
*/
@@ -135,7 +135,7 @@ l_noret luaD_throw (lua_State *L, int errcode) {
int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
- unsigned short oldnCcalls = L->nCcalls;
+ unsigned short oldnCcalls = L->nCcalls - L->nci;
struct lua_longjmp lj;
lj.status = LUA_OK;
lj.previous = L->errorJmp; /* chain new error handler */
@@ -144,7 +144,7 @@ int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
(*f)(L, ud);
);
L->errorJmp = lj.previous; /* restore old error handler */
- L->nCcalls = oldnCcalls;
+ L->nCcalls = oldnCcalls + L->nci;
return lj.status;
}
@@ -299,7 +299,7 @@ static void callhook (lua_State *L, CallInfo *ci, int istail) {
/*
** Check whether __call metafield of 'func' is a function. If so, put
-** it in stack below original 'func' so that 'luaD_precall' can call
+** it in stack below original 'func' so that 'luaD_call' can call
** it. Raise an error if __call metafield is not a function.
*/
StkId luaD_tryfuncTM (lua_State *L, StkId func) {
@@ -417,13 +417,12 @@ void luaD_pretailcall (lua_State *L, CallInfo *ci, StkId func, int n) {
/*
-** Prepares a function call: checks the stack, creates a new CallInfo
-** entry, fills in the relevant information, calls hook if needed.
-** If function is a C function, does the call, too. (Otherwise, leave
-** the execution ('luaV_execute') to the caller, to allow stackless
-** calls.) Returns true iff function has been executed (C function).
+** Call a function (C or Lua). The function to be called is at *func.
+** The arguments are on the stack, right after the function.
+** When returns, all the results are on the stack, starting at the original
+** function position.
*/
-int luaD_precall (lua_State *L, StkId func, int nresults) {
+void luaD_call (lua_State *L, StkId func, int nresults) {
lua_CFunction f;
TValue *funcv = s2v(func);
CallInfo *ci;
@@ -449,7 +448,7 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
lua_lock(L);
api_checknelems(L, n);
luaD_poscall(L, ci, L->top - n, n);
- return 1;
+ break;
}
case LUA_TLCL: { /* Lua function: prepare its call */
Proto *p = clLvalue(funcv)->p;
@@ -469,46 +468,18 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
ci->callstatus = CIST_LUA;
if (L->hookmask)
callhook(L, ci, 0);
- return 0;
+ luaV_execute(L); /* run the function */
+ break;
}
default: { /* not a function */
func = luaD_tryfuncTM(L, func); /* try to get '__call' metamethod */
- return luaD_precall(L, func, nresults); /* now it must be a function */
+ luaD_call(L, func, nresults); /* now it must be a function */
+ break;
}
}
}
-/*
-** Check appropriate error for stack overflow ("regular" overflow or
-** overflow while handling stack overflow). If 'nCalls' is larger than
-** LUAI_MAXCCALLS (which means it is handling a "regular" overflow) but
-** smaller than 9/8 of LUAI_MAXCCALLS, does not report an error (to
-** allow overflow handling to work)
-*/
-static void stackerror (lua_State *L) {
- if (L->nCcalls == LUAI_MAXCCALLS)
- luaG_runerror(L, "C stack overflow");
- else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3)))
- luaD_throw(L, LUA_ERRERR); /* error while handing stack error */
-}
-
-
-/*
-** Call a function (C or Lua). The function to be called is at *func.
-** The arguments are on the stack, right after the function.
-** When returns, all the results are on the stack, starting at the original
-** function position.
-*/
-void luaD_call (lua_State *L, StkId func, int nResults) {
- if (++L->nCcalls >= LUAI_MAXCCALLS)
- stackerror(L);
- if (!luaD_precall(L, func, nResults)) /* is a Lua function? */
- luaV_execute(L); /* call it */
- L->nCcalls--;
-}
-
-
/*
** Similar to 'luaD_call', but does not allow yields during the call
*/
@@ -541,7 +512,7 @@ static void finishCcall (lua_State *L, int status) {
n = (*ci->u.c.k)(L, status, ci->u.c.ctx); /* call continuation function */
lua_lock(L);
api_checknelems(L, n);
- luaD_poscall(L, ci, L->top - n, n); /* finish 'luaD_precall' */
+ luaD_poscall(L, ci, L->top - n, n); /* finish 'luaD_call' */
}
@@ -629,8 +600,7 @@ static void resume (lua_State *L, void *ud) {
StkId firstArg = L->top - n; /* first argument */
CallInfo *ci = L->ci;
if (L->status == LUA_OK) { /* starting a coroutine? */
- if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */
- luaV_execute(L); /* call it */
+ luaD_call(L, firstArg - 1, LUA_MULTRET);
}
else { /* resuming from previous yield */
lua_assert(L->status == LUA_YIELD);
@@ -645,7 +615,7 @@ static void resume (lua_State *L, void *ud) {
api_checknelems(L, n);
firstArg = L->top - n; /* yield results come from continuation */
}
- luaD_poscall(L, ci, firstArg, n); /* finish 'luaD_precall' */
+ luaD_poscall(L, ci, firstArg, n); /* finish 'luaD_call' */
}
unroll(L, NULL); /* run continuation */
}
@@ -688,7 +658,7 @@ LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs,
: L->top - (L->ci->func + 1);
L->nny = oldnny; /* restore 'nny' */
L->nCcalls--;
- lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0));
+ // lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0));
lua_unlock(L);
return status;
}
--
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