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Use a limited history buffer for tailcall counts while recording.

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This commit is contained in:
Mike Pall 2010-02-18 19:32:13 +01:00
parent 65586ca4dc
commit b11eeab906
2 changed files with 17 additions and 14 deletions
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2
src/lj_jit.h
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@ -229,7 +229,7 @@ typedef struct jit_State {
int32_t instunroll; /* Unroll counter for instable loops. */
int32_t loopunroll; /* Unroll counter for loop ops in side traces. */
int32_t tailcalled; /* Number of successive tailcalls. */
uint64_t tailcalled; /* History of the number of successive tailcalls. */
int32_t framedepth; /* Current frame depth. */
int32_t retdepth; /* Return frame depth (count of RETF). */

29
src/lj_record.c
View File

@ -473,8 +473,8 @@ static void rec_loop_jit(jit_State *J, TraceNo lnk, LoopEvent ev)
/* -- Record calls and returns -------------------------------------------- */
/* Record call. */
static void rec_call(jit_State *J, BCReg func, ptrdiff_t nargs)
/* Record call setup. */
static void rec_call_setup(jit_State *J, BCReg func, ptrdiff_t nargs)
{
RecordIndex ix;
TValue *functv = &J->L->base[func];
@ -496,24 +496,30 @@ static void rec_call(jit_State *J, BCReg func, ptrdiff_t nargs)
trfunc = lj_ir_kfunc(J, funcV(functv));
emitir(IRTG(IR_EQ, IRT_FUNC), fbase[0], trfunc);
fbase[0] = trfunc | TREF_FRAME;
J->maxslot = nargs;
}
/* Record call. */
static void rec_call(jit_State *J, BCReg func, ptrdiff_t nargs)
{
rec_call_setup(J, func, nargs);
/* Bump frame. */
J->framedepth++;
J->tailcalled <<= 8; /* NYI: tail call history overflow is ignored. */
J->base += func+1;
J->baseslot += func+1;
J->maxslot = nargs;
}
/* Record tail call. */
static void rec_tailcall(jit_State *J, BCReg func, ptrdiff_t nargs)
{
rec_call(J, func, nargs);
rec_call_setup(J, func, nargs);
/* Move func + args down. */
J->framedepth--;
J->base -= func+1;
J->baseslot -= func+1;
memmove(&J->base[-1], &J->base[func], sizeof(TRef)*(J->maxslot+1));
/* Note: the new TREF_FRAME is now at J->base[-1] (even for slot #0). */
/* Tailcalls can form a loop, so count towards the loop unroll limit. */
if ((int32_t)(++J->tailcalled & 0xff) > J->loopunroll)
lj_trace_err(J, LJ_TRERR_LUNROLL);
}
/* Record return. */
@ -521,6 +527,7 @@ static void rec_ret(jit_State *J, BCReg rbase, ptrdiff_t gotresults)
{
TValue *frame = J->L->base - 1;
ptrdiff_t i;
J->tailcalled >>= 8;
for (i = 0; i < gotresults; i++)
getslot(J, rbase+i); /* Ensure all results have a reference. */
while (frame_ispcall(frame)) { /* Immediately resolve pcall() returns. */
@ -1693,7 +1700,7 @@ static uint32_t recdef_lookup(GCfunc *fn)
return 0;
}
/* Record call to fast function or C function. */
/* Record entry to a fast function or C function. */
static void rec_func_ff(jit_State *J)
{
RecordFFData rd;
@ -1719,7 +1726,7 @@ static void check_call_unroll(jit_State *J)
if ((J->slot[s] & TREF_FRAME) && tref_ref(J->slot[s]) == fref)
count++;
if (J->pc == J->startpc) {
if (count + J->tailcalled > J->param[JIT_P_recunroll])
if (count + (int32_t)(J->tailcalled & 0xff) > J->param[JIT_P_recunroll])
lj_trace_err(J, LJ_TRERR_NYIRECU);
} else {
if (count > J->param[JIT_P_callunroll])
@ -2057,9 +2064,6 @@ void lj_record_ins(jit_State *J)
/* fallthrough */
case BC_CALLT:
rec_tailcall(J, ra, (ptrdiff_t)rc-1);
/* Tailcalls can form a loop, so count towards the loop unroll limit. */
if (++J->tailcalled > J->loopunroll)
lj_trace_err(J, LJ_TRERR_LUNROLL);
break;
/* -- Returns ----------------------------------------------------------- */
@ -2070,7 +2074,6 @@ void lj_record_ins(jit_State *J)
/* fallthrough */
case BC_RET: case BC_RET0: case BC_RET1:
rec_ret(J, ra, (ptrdiff_t)rc-1);
J->tailcalled = 0; /* NYI: logic is broken, need a better check. */
break;
/* -- Loops and branches ------------------------------------------------ */