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commit b114c7d4871051cbdd7af185a61f35fe4028da79
parent 9cbf17b0f1bb4001b237c4027b271f0db9bde62c
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date:   Tue, 11 Sep 2018 14:23:47 -0300

Added "cost" for the use of C stack by a coroutine invocation.

Resuming a coroutine uses more C stack than other operations (such as
function calls or recursive syntax). So, to avoid stack overflow
in recursive coroutine invocations, either LUAI_MAXCCALLS must be
too small or a coroutine invocation must "pay" a higher price.
New constant LUAL_COROCSTK ("COROutine C STaK") defines how much
is this price.

Diffstat:
Mldo.c | 10++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/ldo.c b/ldo.c @@ -611,6 +611,13 @@ static int resume_error (lua_State *L, const char *msg, int narg) { /* +** "Cost" in the C stack for a coroutine invocation. +*/ +#if !defined(LUAL_COROCSTK) +#define LUAL_COROCSTK 3 +#endif + +/* ** Do the work for 'lua_resume' in protected mode. Most of the work ** depends on the status of the coroutine: initial state, suspended ** inside a hook, or regularly suspended (optionally with a continuation @@ -642,7 +649,6 @@ static void resume (lua_State *L, void *ud) { } } - LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs, int *nresults) { int status; @@ -657,7 +663,7 @@ LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs, if (from == NULL) L->nCcalls = 1; else /* correct 'nCcalls' for this thread */ - L->nCcalls = from->nCcalls - from->nci + L->nci + 1; + L->nCcalls = from->nCcalls - from->nci + L->nci + LUAL_COROCSTK; if (L->nCcalls >= LUAI_MAXCCALLS) return resume_error(L, "C stack overflow", nargs); luai_userstateresume(L, nargs);