Correct handling of 'luaV_execute' invocations
The previous stackless implementations marked all 'luaV_execute'
invocations as fresh. However, re-entering 'luaV_execute' when
resuming a coroutine should not be a fresh invocation. (It works
because 'unroll' called 'luaV_execute' for each call entry, but
it was slower than letting 'luaV_execute' finish all non-fresh
invocations.)
diff --git a/ldo.c b/ldo.c
index 0a6a716..052c57a 100644
--- a/ldo.c
+++ b/ldo.c
@@ -449,12 +449,13 @@
/*
** Prepares the call to a function (C or Lua). For C functions, also do
-** the call. The function to be called is at '*func'. The arguments are
-** on the stack, right after the function. Returns true if the call was
-** made (it was a C function). When returns true, all the results are
-** on the stack, starting at the original function position.
+** the call. The function to be called is at '*func'. The arguments
+** are on the stack, right after the function. Returns the CallInfo
+** to be executed, if it was a Lua function. Otherwise (a C function)
+** returns NULL, with all the results on the stack, starting at the
+** original function position.
*/
-int luaD_precall (lua_State *L, StkId func, int nresults) {
+CallInfo *luaD_precall (lua_State *L, StkId func, int nresults) {
lua_CFunction f;
retry:
switch (ttypetag(s2v(func))) {
@@ -482,7 +483,7 @@
lua_lock(L);
api_checknelems(L, n);
luaD_poscall(L, ci, n);
- return 1;
+ return NULL;
}
case LUA_VLCL: { /* Lua function */
CallInfo *ci;
@@ -494,14 +495,13 @@
L->ci = ci = next_ci(L);
ci->nresults = nresults;
ci->u.l.savedpc = p->code; /* starting point */
- ci->callstatus = 0;
ci->top = func + 1 + fsize;
ci->func = func;
L->ci = ci;
for (; narg < nfixparams; narg++)
setnilvalue(s2v(L->top++)); /* complete missing arguments */
lua_assert(ci->top <= L->stack_last);
- return 0;
+ return ci;
}
default: { /* not a function */
checkstackGCp(L, 1, func); /* space for metamethod */
@@ -518,11 +518,14 @@
** increment number of non-yieldable calls).
*/
static void docall (lua_State *L, StkId func, int nResults, int inc) {
+ CallInfo *ci;
L->nCcalls += inc;
- if (getCcalls(L) >= LUAI_MAXCCALLS)
+ if (unlikely(getCcalls(L) >= LUAI_MAXCCALLS))
luaE_checkcstack(L);
- if (!luaD_precall(L, func, nResults)) /* is a Lua function? */
- luaV_execute(L, L->ci); /* call it */
+ if ((ci = luaD_precall(L, func, nResults)) != NULL) { /* Lua function? */
+ ci->callstatus = CIST_FRESH; /* mark that it is a "fresh" execute */
+ luaV_execute(L, ci); /* call it */
+ }
L->nCcalls -= inc;
}
diff --git a/ldo.h b/ldo.h
index 7d03211..4d30d07 100644
--- a/ldo.h
+++ b/ldo.h
@@ -59,7 +59,7 @@
int fTransfer, int nTransfer);
LUAI_FUNC void luaD_hookcall (lua_State *L, CallInfo *ci);
LUAI_FUNC void luaD_pretailcall (lua_State *L, CallInfo *ci, StkId func, int n);
-LUAI_FUNC int luaD_precall (lua_State *L, StkId func, int nResults);
+LUAI_FUNC CallInfo *luaD_precall (lua_State *L, StkId func, int nResults);
LUAI_FUNC void luaD_call (lua_State *L, StkId func, int nResults);
LUAI_FUNC void luaD_callnoyield (lua_State *L, StkId func, int nResults);
LUAI_FUNC void luaD_tryfuncTM (lua_State *L, StkId func);
diff --git a/lstate.c b/lstate.c
index bd1b512..13c1ff0 100644
--- a/lstate.c
+++ b/lstate.c
@@ -172,7 +172,7 @@
LUAI_FUNC void luaE_incCstack (lua_State *L) {
L->nCcalls++;
- if (getCcalls(L) >= LUAI_MAXCCALLS)
+ if (unlikely(getCcalls(L) >= LUAI_MAXCCALLS))
luaE_checkcstack(L);
}
diff --git a/lstate.h b/lstate.h
index a05db37..5573898 100644
--- a/lstate.h
+++ b/lstate.h
@@ -183,14 +183,15 @@
*/
#define CIST_OAH (1<<0) /* original value of 'allowhook' */
#define CIST_C (1<<1) /* call is running a C function */
-#define CIST_HOOKED (1<<2) /* call is running a debug hook */
-#define CIST_YPCALL (1<<3) /* call is a yieldable protected call */
-#define CIST_TAIL (1<<4) /* call was tail called */
-#define CIST_HOOKYIELD (1<<5) /* last hook called yielded */
-#define CIST_FIN (1<<6) /* call is running a finalizer */
-#define CIST_TRAN (1<<7) /* 'ci' has transfer information */
+#define CIST_FRESH (1<<2) /* call is on a fresh "luaV_execute" frame */
+#define CIST_HOOKED (1<<3) /* call is running a debug hook */
+#define CIST_YPCALL (1<<4) /* call is a yieldable protected call */
+#define CIST_TAIL (1<<5) /* call was tail called */
+#define CIST_HOOKYIELD (1<<6) /* last hook called yielded */
+#define CIST_FIN (1<<7) /* call is running a finalizer */
+#define CIST_TRAN (1<<8) /* 'ci' has transfer information */
#if defined(LUA_COMPAT_LT_LE)
-#define CIST_LEQ (1<<8) /* using __lt for __le */
+#define CIST_LEQ (1<<9) /* using __lt for __le */
#endif
/* active function is a Lua function */
diff --git a/lvm.c b/lvm.c
index eadf66b..51b22d8 100644
--- a/lvm.c
+++ b/lvm.c
@@ -1124,7 +1124,6 @@
void luaV_execute (lua_State *L, CallInfo *ci) {
- CallInfo * const origci = ci;
LClosure *cl;
TValue *k;
StkId base;
@@ -1133,7 +1132,7 @@
#if LUA_USE_JUMPTABLE
#include "ljumptab.h"
#endif
- tailcall:
+ execute:
trap = L->hookmask;
cl = clLvalue(s2v(ci->func));
k = cl->p->k;
@@ -1607,17 +1606,19 @@
vmbreak;
}
vmcase(OP_CALL) {
+ CallInfo *newci;
int b = GETARG_B(i);
int nresults = GETARG_C(i) - 1;
if (b != 0) /* fixed number of arguments? */
L->top = ra + b; /* top signals number of arguments */
/* else previous instruction set top */
savepc(L); /* in case of errors */
- if (luaD_precall(L, ra, nresults))
+ if ((newci = luaD_precall(L, ra, nresults)) == NULL)
updatetrap(ci); /* C call; nothing else to be done */
else { /* Lua call: run function in this same invocation */
- ci = L->ci;
- goto tailcall;
+ ci = newci;
+ ci->callstatus = 0; /* call re-uses 'luaV_execute' */
+ goto execute;
}
vmbreak;
}
@@ -1647,13 +1648,13 @@
luaD_precall(L, ra, LUA_MULTRET); /* call it */
updatetrap(ci);
updatestack(ci); /* stack may have been relocated */
- ci->func -= delta;
+ ci->func -= delta; /* restore 'func' (if vararg) */
luaD_poscall(L, ci, cast_int(L->top - ra)); /* finish caller */
- goto ret;
+ goto ret; /* caller returns after the tail call */
}
- ci->func -= delta;
+ ci->func -= delta; /* restore 'func' (if vararg) */
luaD_pretailcall(L, ci, ra, b); /* prepare call frame */
- goto tailcall;
+ goto execute; /* execute the callee */
}
vmcase(OP_RETURN) {
int n = GETARG_B(i) - 1; /* number of results */
@@ -1706,11 +1707,11 @@
}
}
ret:
- if (ci == origci)
- return;
+ if (ci->callstatus & CIST_FRESH)
+ return; /* end this frame */
else {
ci = ci->previous;
- goto tailcall;
+ goto execute; /* continue running caller in this frame */
}
}
vmcase(OP_FORLOOP) {
