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Aegisub/subprojects/luajit/src/lj_trace.c

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/*
** Trace management.
** Copyright (C) 2005-2017 Mike Pall. See Copyright Notice in luajit.h
*/
#define lj_trace_c
#define LUA_CORE
#include "lj_obj.h"
#if LJ_HASJIT
#include "lj_gc.h"
#include "lj_err.h"
#include "lj_debug.h"
#include "lj_str.h"
#include "lj_frame.h"
#include "lj_state.h"
#include "lj_bc.h"
#include "lj_ir.h"
#include "lj_jit.h"
#include "lj_iropt.h"
#include "lj_mcode.h"
#include "lj_trace.h"
#include "lj_snap.h"
#include "lj_gdbjit.h"
#include "lj_record.h"
#include "lj_asm.h"
#include "lj_dispatch.h"
#include "lj_vm.h"
#include "lj_vmevent.h"
#include "lj_target.h"
/* -- Error handling ------------------------------------------------------ */
/* Synchronous abort with error message. */
void lj_trace_err(jit_State *J, TraceError e)
{
setnilV(&J->errinfo); /* No error info. */
setintV(J->L->top++, (int32_t)e);
lj_err_throw(J->L, LUA_ERRRUN);
}
/* Synchronous abort with error message and error info. */
void lj_trace_err_info(jit_State *J, TraceError e)
{
setintV(J->L->top++, (int32_t)e);
lj_err_throw(J->L, LUA_ERRRUN);
}
/* -- Trace management ---------------------------------------------------- */
/* The current trace is first assembled in J->cur. The variable length
** arrays point to shared, growable buffers (J->irbuf etc.). When trace
** recording ends successfully, the current trace and its data structures
** are copied to a new (compact) GCtrace object.
*/
/* Find a free trace number. */
static TraceNo trace_findfree(jit_State *J)
{
MSize osz, lim;
if (J->freetrace == 0)
J->freetrace = 1;
for (; J->freetrace < J->sizetrace; J->freetrace++)
if (traceref(J, J->freetrace) == NULL)
return J->freetrace++;
/* Need to grow trace array. */
lim = (MSize)J->param[JIT_P_maxtrace] + 1;
if (lim < 2) lim = 2; else if (lim > 65535) lim = 65535;
osz = J->sizetrace;
if (osz >= lim)
return 0; /* Too many traces. */
lj_mem_growvec(J->L, J->trace, J->sizetrace, lim, GCRef);
for (; osz < J->sizetrace; osz++)
setgcrefnull(J->trace[osz]);
return J->freetrace;
}
#define TRACE_APPENDVEC(field, szfield, tp) \
T->field = (tp *)p; \
memcpy(p, J->cur.field, J->cur.szfield*sizeof(tp)); \
p += J->cur.szfield*sizeof(tp);
#ifdef LUAJIT_USE_PERFTOOLS
/*
** Create symbol table of JIT-compiled code. For use with Linux perf tools.
** Example usage:
** perf record -f -e cycles luajit test.lua
** perf report -s symbol
** rm perf.data /tmp/perf-*.map
*/
#include <stdio.h>
#include <unistd.h>
static void perftools_addtrace(GCtrace *T)
{
static FILE *fp;
GCproto *pt = &gcref(T->startpt)->pt;
const BCIns *startpc = mref(T->startpc, const BCIns);
const char *name = proto_chunknamestr(pt);
BCLine lineno;
if (name[0] == '@' || name[0] == '=')
name++;
else
name = "(string)";
lua_assert(startpc >= proto_bc(pt) && startpc < proto_bc(pt) + pt->sizebc);
lineno = lj_debug_line(pt, proto_bcpos(pt, startpc));
if (!fp) {
char fname[40];
sprintf(fname, "/tmp/perf-%d.map", getpid());
if (!(fp = fopen(fname, "w"))) return;
setlinebuf(fp);
}
fprintf(fp, "%lx %x TRACE_%d::%s:%u\n",
(long)T->mcode, T->szmcode, T->traceno, name, lineno);
}
#endif
/* Allocate space for copy of trace. */
static GCtrace *trace_save_alloc(jit_State *J)
{
size_t sztr = ((sizeof(GCtrace)+7)&~7);
size_t szins = (J->cur.nins-J->cur.nk)*sizeof(IRIns);
size_t sz = sztr + szins +
J->cur.nsnap*sizeof(SnapShot) +
J->cur.nsnapmap*sizeof(SnapEntry);
return lj_mem_newt(J->L, (MSize)sz, GCtrace);
}
/* Save current trace by copying and compacting it. */
static void trace_save(jit_State *J, GCtrace *T)
{
size_t sztr = ((sizeof(GCtrace)+7)&~7);
size_t szins = (J->cur.nins-J->cur.nk)*sizeof(IRIns);
char *p = (char *)T + sztr;
memcpy(T, &J->cur, sizeof(GCtrace));
setgcrefr(T->nextgc, J2G(J)->gc.root);
setgcrefp(J2G(J)->gc.root, T);
newwhite(J2G(J), T);
T->gct = ~LJ_TTRACE;
T->ir = (IRIns *)p - J->cur.nk;
memcpy(p, J->cur.ir+J->cur.nk, szins);
p += szins;
TRACE_APPENDVEC(snap, nsnap, SnapShot)
TRACE_APPENDVEC(snapmap, nsnapmap, SnapEntry)
J->cur.traceno = 0;
setgcrefp(J->trace[T->traceno], T);
lj_gc_barriertrace(J2G(J), T->traceno);
lj_gdbjit_addtrace(J, T);
#ifdef LUAJIT_USE_PERFTOOLS
perftools_addtrace(T);
#endif
}
void LJ_FASTCALL lj_trace_free(global_State *g, GCtrace *T)
{
jit_State *J = G2J(g);
if (T->traceno) {
lj_gdbjit_deltrace(J, T);
if (T->traceno < J->freetrace)
J->freetrace = T->traceno;
setgcrefnull(J->trace[T->traceno]);
}
lj_mem_free(g, T,
((sizeof(GCtrace)+7)&~7) + (T->nins-T->nk)*sizeof(IRIns) +
T->nsnap*sizeof(SnapShot) + T->nsnapmap*sizeof(SnapEntry));
}
/* Re-enable compiling a prototype by unpatching any modified bytecode. */
void lj_trace_reenableproto(GCproto *pt)
{
if ((pt->flags & PROTO_ILOOP)) {
BCIns *bc = proto_bc(pt);
BCPos i, sizebc = pt->sizebc;;
pt->flags &= ~PROTO_ILOOP;
if (bc_op(bc[0]) == BC_IFUNCF)
setbc_op(&bc[0], BC_FUNCF);
for (i = 1; i < sizebc; i++) {
BCOp op = bc_op(bc[i]);
if (op == BC_IFORL || op == BC_IITERL || op == BC_ILOOP)
setbc_op(&bc[i], (int)op+(int)BC_LOOP-(int)BC_ILOOP);
}
}
}
/* Unpatch the bytecode modified by a root trace. */
static void trace_unpatch(jit_State *J, GCtrace *T)
{
BCOp op = bc_op(T->startins);
BCIns *pc = mref(T->startpc, BCIns);
UNUSED(J);
if (op == BC_JMP)
return; /* No need to unpatch branches in parent traces (yet). */
switch (bc_op(*pc)) {
case BC_JFORL:
lua_assert(traceref(J, bc_d(*pc)) == T);
*pc = T->startins;
pc += bc_j(T->startins);
lua_assert(bc_op(*pc) == BC_JFORI);
setbc_op(pc, BC_FORI);
break;
case BC_JITERL:
case BC_JLOOP:
lua_assert(op == BC_ITERL || op == BC_LOOP || bc_isret(op));
*pc = T->startins;
break;
case BC_JMP:
lua_assert(op == BC_ITERL);
pc += bc_j(*pc)+2;
if (bc_op(*pc) == BC_JITERL) {
lua_assert(traceref(J, bc_d(*pc)) == T);
*pc = T->startins;
}
break;
case BC_JFUNCF:
lua_assert(op == BC_FUNCF);
*pc = T->startins;
break;
default: /* Already unpatched. */
break;
}
}
/* Flush a root trace. */
static void trace_flushroot(jit_State *J, GCtrace *T)
{
GCproto *pt = &gcref(T->startpt)->pt;
lua_assert(T->root == 0 && pt != NULL);
/* First unpatch any modified bytecode. */
trace_unpatch(J, T);
/* Unlink root trace from chain anchored in prototype. */
if (pt->trace == T->traceno) { /* Trace is first in chain. Easy. */
pt->trace = T->nextroot;
} else if (pt->trace) { /* Otherwise search in chain of root traces. */
GCtrace *T2 = traceref(J, pt->trace);
if (T2) {
for (; T2->nextroot; T2 = traceref(J, T2->nextroot))
if (T2->nextroot == T->traceno) {
T2->nextroot = T->nextroot; /* Unlink from chain. */
break;
}
}
}
}
/* Flush a trace. Only root traces are considered. */
void lj_trace_flush(jit_State *J, TraceNo traceno)
{
if (traceno > 0 && traceno < J->sizetrace) {
GCtrace *T = traceref(J, traceno);
if (T && T->root == 0)
trace_flushroot(J, T);
}
}
/* Flush all traces associated with a prototype. */
void lj_trace_flushproto(global_State *g, GCproto *pt)
{
while (pt->trace != 0)
trace_flushroot(G2J(g), traceref(G2J(g), pt->trace));
}
/* Flush all traces. */
int lj_trace_flushall(lua_State *L)
{
jit_State *J = L2J(L);
ptrdiff_t i;
if ((J2G(J)->hookmask & HOOK_GC))
return 1;
for (i = (ptrdiff_t)J->sizetrace-1; i > 0; i--) {
GCtrace *T = traceref(J, i);
if (T) {
if (T->root == 0)
trace_flushroot(J, T);
lj_gdbjit_deltrace(J, T);
T->traceno = 0;
setgcrefnull(J->trace[i]);
}
}
J->cur.traceno = 0;
J->freetrace = 0;
/* Clear penalty cache. */
memset(J->penalty, 0, sizeof(J->penalty));
/* Free the whole machine code and invalidate all exit stub groups. */
lj_mcode_free(J);
memset(J->exitstubgroup, 0, sizeof(J->exitstubgroup));
lj_vmevent_send(L, TRACE,
setstrV(L, L->top++, lj_str_newlit(L, "flush"));
);
return 0;
}
/* Initialize JIT compiler state. */
void lj_trace_initstate(global_State *g)
{
jit_State *J = G2J(g);
TValue *tv;
/* Initialize SIMD constants. */
tv = LJ_KSIMD(J, LJ_KSIMD_ABS);
tv[0].u64 = U64x(7fffffff,ffffffff);
tv[1].u64 = U64x(7fffffff,ffffffff);
tv = LJ_KSIMD(J, LJ_KSIMD_NEG);
tv[0].u64 = U64x(80000000,00000000);
tv[1].u64 = U64x(80000000,00000000);
}
/* Free everything associated with the JIT compiler state. */
void lj_trace_freestate(global_State *g)
{
jit_State *J = G2J(g);
#ifdef LUA_USE_ASSERT
{ /* This assumes all traces have already been freed. */
ptrdiff_t i;
for (i = 1; i < (ptrdiff_t)J->sizetrace; i++)
lua_assert(i == (ptrdiff_t)J->cur.traceno || traceref(J, i) == NULL);
}
#endif
lj_mcode_free(J);
lj_ir_k64_freeall(J);
lj_mem_freevec(g, J->snapmapbuf, J->sizesnapmap, SnapEntry);
lj_mem_freevec(g, J->snapbuf, J->sizesnap, SnapShot);
lj_mem_freevec(g, J->irbuf + J->irbotlim, J->irtoplim - J->irbotlim, IRIns);
lj_mem_freevec(g, J->trace, J->sizetrace, GCRef);
}
/* -- Penalties and blacklisting ------------------------------------------ */
/* Blacklist a bytecode instruction. */
static void blacklist_pc(GCproto *pt, BCIns *pc)
{
setbc_op(pc, (int)bc_op(*pc)+(int)BC_ILOOP-(int)BC_LOOP);
pt->flags |= PROTO_ILOOP;
}
/* Penalize a bytecode instruction. */
static void penalty_pc(jit_State *J, GCproto *pt, BCIns *pc, TraceError e)
{
uint32_t i, val = PENALTY_MIN;
for (i = 0; i < PENALTY_SLOTS; i++)
if (mref(J->penalty[i].pc, const BCIns) == pc) { /* Cache slot found? */
/* First try to bump its hotcount several times. */
val = ((uint32_t)J->penalty[i].val << 1) +
LJ_PRNG_BITS(J, PENALTY_RNDBITS);
if (val > PENALTY_MAX) {
blacklist_pc(pt, pc); /* Blacklist it, if that didn't help. */
return;
}
goto setpenalty;
}
/* Assign a new penalty cache slot. */
i = J->penaltyslot;
J->penaltyslot = (J->penaltyslot + 1) & (PENALTY_SLOTS-1);
setmref(J->penalty[i].pc, pc);
setpenalty:
J->penalty[i].val = (uint16_t)val;
J->penalty[i].reason = e;
hotcount_set(J2GG(J), pc+1, val);
}
/* -- Trace compiler state machine ---------------------------------------- */
/* Start tracing. */
static void trace_start(jit_State *J)
{
lua_State *L;
TraceNo traceno;
if ((J->pt->flags & PROTO_NOJIT)) { /* JIT disabled for this proto? */
if (J->parent == 0) {
/* Lazy bytecode patching to disable hotcount events. */
lua_assert(bc_op(*J->pc) == BC_FORL || bc_op(*J->pc) == BC_ITERL ||
bc_op(*J->pc) == BC_LOOP || bc_op(*J->pc) == BC_FUNCF);
setbc_op(J->pc, (int)bc_op(*J->pc)+(int)BC_ILOOP-(int)BC_LOOP);
J->pt->flags |= PROTO_ILOOP;
}
J->state = LJ_TRACE_IDLE; /* Silently ignored. */
return;
}
/* Get a new trace number. */
traceno = trace_findfree(J);
if (LJ_UNLIKELY(traceno == 0)) { /* No free trace? */
lua_assert((J2G(J)->hookmask & HOOK_GC) == 0);
lj_trace_flushall(J->L);
J->state = LJ_TRACE_IDLE; /* Silently ignored. */
return;
}
setgcrefp(J->trace[traceno], &J->cur);
/* Setup enough of the current trace to be able to send the vmevent. */
memset(&J->cur, 0, sizeof(GCtrace));
J->cur.traceno = traceno;
J->cur.nins = J->cur.nk = REF_BASE;
J->cur.ir = J->irbuf;
J->cur.snap = J->snapbuf;
J->cur.snapmap = J->snapmapbuf;
J->mergesnap = 0;
J->needsnap = 0;
J->bcskip = 0;
J->guardemit.irt = 0;
J->postproc = LJ_POST_NONE;
lj_resetsplit(J);
setgcref(J->cur.startpt, obj2gco(J->pt));
L = J->L;
lj_vmevent_send(L, TRACE,
setstrV(L, L->top++, lj_str_newlit(L, "start"));
setintV(L->top++, traceno);
setfuncV(L, L->top++, J->fn);
setintV(L->top++, proto_bcpos(J->pt, J->pc));
if (J->parent) {
setintV(L->top++, J->parent);
setintV(L->top++, J->exitno);
}
);
lj_record_setup(J);
}
/* Stop tracing. */
static void trace_stop(jit_State *J)
{
BCIns *pc = mref(J->cur.startpc, BCIns);
BCOp op = bc_op(J->cur.startins);
GCproto *pt = &gcref(J->cur.startpt)->pt;
TraceNo traceno = J->cur.traceno;
GCtrace *T = trace_save_alloc(J); /* Do this first. May throw OOM. */
lua_State *L;
switch (op) {
case BC_FORL:
setbc_op(pc+bc_j(J->cur.startins), BC_JFORI); /* Patch FORI, too. */
/* fallthrough */
case BC_LOOP:
case BC_ITERL:
case BC_FUNCF:
/* Patch bytecode of starting instruction in root trace. */
setbc_op(pc, (int)op+(int)BC_JLOOP-(int)BC_LOOP);
setbc_d(pc, traceno);
addroot:
/* Add to root trace chain in prototype. */
J->cur.nextroot = pt->trace;
pt->trace = (TraceNo1)traceno;
break;
case BC_RET:
case BC_RET0:
case BC_RET1:
*pc = BCINS_AD(BC_JLOOP, J->cur.snap[0].nslots, traceno);
goto addroot;
case BC_JMP:
/* Patch exit branch in parent to side trace entry. */
lua_assert(J->parent != 0 && J->cur.root != 0);
lj_asm_patchexit(J, traceref(J, J->parent), J->exitno, J->cur.mcode);
/* Avoid compiling a side trace twice (stack resizing uses parent exit). */
traceref(J, J->parent)->snap[J->exitno].count = SNAPCOUNT_DONE;
/* Add to side trace chain in root trace. */
{
GCtrace *root = traceref(J, J->cur.root);
root->nchild++;
J->cur.nextside = root->nextside;
root->nextside = (TraceNo1)traceno;
}
break;
default:
lua_assert(0);
break;
}
/* Commit new mcode only after all patching is done. */
lj_mcode_commit(J, J->cur.mcode);
J->postproc = LJ_POST_NONE;
trace_save(J, T);
L = J->L;
lj_vmevent_send(L, TRACE,
setstrV(L, L->top++, lj_str_newlit(L, "stop"));
setintV(L->top++, traceno);
);
}
/* Start a new root trace for down-recursion. */
static int trace_downrec(jit_State *J)
{
/* Restart recording at the return instruction. */
lua_assert(J->pt != NULL);
lua_assert(bc_isret(bc_op(*J->pc)));
if (bc_op(*J->pc) == BC_RETM)
return 0; /* NYI: down-recursion with RETM. */
J->parent = 0;
J->exitno = 0;
J->state = LJ_TRACE_RECORD;
trace_start(J);
return 1;
}
/* Abort tracing. */
static int trace_abort(jit_State *J)
{
lua_State *L = J->L;
TraceError e = LJ_TRERR_RECERR;
TraceNo traceno;
J->postproc = LJ_POST_NONE;
lj_mcode_abort(J);
if (tvisnumber(L->top-1))
e = (TraceError)numberVint(L->top-1);
if (e == LJ_TRERR_MCODELM) {
L->top--; /* Remove error object */
J->state = LJ_TRACE_ASM;
return 1; /* Retry ASM with new MCode area. */
}
/* Penalize or blacklist starting bytecode instruction. */
if (J->parent == 0 && !bc_isret(bc_op(J->cur.startins)))
penalty_pc(J, &gcref(J->cur.startpt)->pt, mref(J->cur.startpc, BCIns), e);
/* Is there anything to abort? */
traceno = J->cur.traceno;
if (traceno) {
ptrdiff_t errobj = savestack(L, L->top-1); /* Stack may be resized. */
J->cur.link = 0;
J->cur.linktype = LJ_TRLINK_NONE;
lj_vmevent_send(L, TRACE,
TValue *frame;
const BCIns *pc;
GCfunc *fn;
setstrV(L, L->top++, lj_str_newlit(L, "abort"));
setintV(L->top++, traceno);
/* Find original Lua function call to generate a better error message. */
frame = J->L->base-1;
pc = J->pc;
while (!isluafunc(frame_func(frame))) {
pc = (frame_iscont(frame) ? frame_contpc(frame) : frame_pc(frame)) - 1;
frame = frame_prev(frame);
}
fn = frame_func(frame);
setfuncV(L, L->top++, fn);
setintV(L->top++, proto_bcpos(funcproto(fn), pc));
copyTV(L, L->top++, restorestack(L, errobj));
copyTV(L, L->top++, &J->errinfo);
);
/* Drop aborted trace after the vmevent (which may still access it). */
setgcrefnull(J->trace[traceno]);
if (traceno < J->freetrace)
J->freetrace = traceno;
J->cur.traceno = 0;
}
L->top--; /* Remove error object */
if (e == LJ_TRERR_DOWNREC)
return trace_downrec(J);
else if (e == LJ_TRERR_MCODEAL)
lj_trace_flushall(L);
return 0;
}
/* Perform pending re-patch of a bytecode instruction. */
static LJ_AINLINE void trace_pendpatch(jit_State *J, int force)
{
if (LJ_UNLIKELY(J->patchpc)) {
if (force || J->bcskip == 0) {
*J->patchpc = J->patchins;
J->patchpc = NULL;
} else {
J->bcskip = 0;
}
}
}
/* State machine for the trace compiler. Protected callback. */
static TValue *trace_state(lua_State *L, lua_CFunction dummy, void *ud)
{
jit_State *J = (jit_State *)ud;
UNUSED(dummy);
do {
retry:
switch (J->state) {
case LJ_TRACE_START:
J->state = LJ_TRACE_RECORD; /* trace_start() may change state. */
trace_start(J);
lj_dispatch_update(J2G(J));
break;
case LJ_TRACE_RECORD:
trace_pendpatch(J, 0);
setvmstate(J2G(J), RECORD);
lj_vmevent_send_(L, RECORD,
/* Save/restore tmptv state for trace recorder. */
TValue savetv = J2G(J)->tmptv;
TValue savetv2 = J2G(J)->tmptv2;
setintV(L->top++, J->cur.traceno);
setfuncV(L, L->top++, J->fn);
setintV(L->top++, J->pt ? (int32_t)proto_bcpos(J->pt, J->pc) : -1);
setintV(L->top++, J->framedepth);
,
J2G(J)->tmptv = savetv;
J2G(J)->tmptv2 = savetv2;
);
lj_record_ins(J);
break;
case LJ_TRACE_END:
trace_pendpatch(J, 1);
J->loopref = 0;
if ((J->flags & JIT_F_OPT_LOOP) &&
J->cur.link == J->cur.traceno && J->framedepth + J->retdepth == 0) {
setvmstate(J2G(J), OPT);
lj_opt_dce(J);
if (lj_opt_loop(J)) { /* Loop optimization failed? */
J->cur.link = 0;
J->cur.linktype = LJ_TRLINK_NONE;
J->loopref = J->cur.nins;
J->state = LJ_TRACE_RECORD; /* Try to continue recording. */
break;
}
J->loopref = J->chain[IR_LOOP]; /* Needed by assembler. */
}
lj_opt_split(J);
lj_opt_sink(J);
if (!J->loopref) J->cur.snap[J->cur.nsnap-1].count = SNAPCOUNT_DONE;
J->state = LJ_TRACE_ASM;
break;
case LJ_TRACE_ASM:
setvmstate(J2G(J), ASM);
lj_asm_trace(J, &J->cur);
trace_stop(J);
setvmstate(J2G(J), INTERP);
J->state = LJ_TRACE_IDLE;
lj_dispatch_update(J2G(J));
return NULL;
default: /* Trace aborted asynchronously. */
setintV(L->top++, (int32_t)LJ_TRERR_RECERR);
/* fallthrough */
case LJ_TRACE_ERR:
trace_pendpatch(J, 1);
if (trace_abort(J))
goto retry;
setvmstate(J2G(J), INTERP);
J->state = LJ_TRACE_IDLE;
lj_dispatch_update(J2G(J));
return NULL;
}
} while (J->state > LJ_TRACE_RECORD);
return NULL;
}
/* -- Event handling ------------------------------------------------------ */
/* A bytecode instruction is about to be executed. Record it. */
void lj_trace_ins(jit_State *J, const BCIns *pc)
{
/* Note: J->L must already be set. pc is the true bytecode PC here. */
J->pc = pc;
J->fn = curr_func(J->L);
J->pt = isluafunc(J->fn) ? funcproto(J->fn) : NULL;
while (lj_vm_cpcall(J->L, NULL, (void *)J, trace_state) != 0)
J->state = LJ_TRACE_ERR;
}
/* A hotcount triggered. Start recording a root trace. */
void LJ_FASTCALL lj_trace_hot(jit_State *J, const BCIns *pc)
{
/* Note: pc is the interpreter bytecode PC here. It's offset by 1. */
ERRNO_SAVE
/* Reset hotcount. */
hotcount_set(J2GG(J), pc, J->param[JIT_P_hotloop]*HOTCOUNT_LOOP);
/* Only start a new trace if not recording or inside __gc call or vmevent. */
if (J->state == LJ_TRACE_IDLE &&
!(J2G(J)->hookmask & (HOOK_GC|HOOK_VMEVENT))) {
J->parent = 0; /* Root trace. */
J->exitno = 0;
J->state = LJ_TRACE_START;
lj_trace_ins(J, pc-1);
}
ERRNO_RESTORE
}
/* Check for a hot side exit. If yes, start recording a side trace. */
static void trace_hotside(jit_State *J, const BCIns *pc)
{
SnapShot *snap = &traceref(J, J->parent)->snap[J->exitno];
if (!(J2G(J)->hookmask & (HOOK_GC|HOOK_VMEVENT)) &&
snap->count != SNAPCOUNT_DONE &&
++snap->count >= J->param[JIT_P_hotexit]) {
lua_assert(J->state == LJ_TRACE_IDLE);
/* J->parent is non-zero for a side trace. */
J->state = LJ_TRACE_START;
lj_trace_ins(J, pc);
}
}
/* Tiny struct to pass data to protected call. */
typedef struct ExitDataCP {
jit_State *J;
void *exptr; /* Pointer to exit state. */
const BCIns *pc; /* Restart interpreter at this PC. */
} ExitDataCP;
/* Need to protect lj_snap_restore because it may throw. */
static TValue *trace_exit_cp(lua_State *L, lua_CFunction dummy, void *ud)
{
ExitDataCP *exd = (ExitDataCP *)ud;
cframe_errfunc(L->cframe) = -1; /* Inherit error function. */
exd->pc = lj_snap_restore(exd->J, exd->exptr);
UNUSED(dummy);
return NULL;
}
#ifndef LUAJIT_DISABLE_VMEVENT
/* Push all registers from exit state. */
static void trace_exit_regs(lua_State *L, ExitState *ex)
{
int32_t i;
setintV(L->top++, RID_NUM_GPR);
setintV(L->top++, RID_NUM_FPR);
for (i = 0; i < RID_NUM_GPR; i++) {
if (sizeof(ex->gpr[i]) == sizeof(int32_t))
setintV(L->top++, (int32_t)ex->gpr[i]);
else
setnumV(L->top++, (lua_Number)ex->gpr[i]);
}
#if !LJ_SOFTFP
for (i = 0; i < RID_NUM_FPR; i++) {
setnumV(L->top, ex->fpr[i]);
if (LJ_UNLIKELY(tvisnan(L->top)))
setnanV(L->top);
L->top++;
}
#endif
}
#endif
#ifdef EXITSTATE_PCREG
/* Determine trace number from pc of exit instruction. */
static TraceNo trace_exit_find(jit_State *J, MCode *pc)
{
TraceNo traceno;
for (traceno = 1; traceno < J->sizetrace; traceno++) {
GCtrace *T = traceref(J, traceno);
if (T && pc >= T->mcode && pc < (MCode *)((char *)T->mcode + T->szmcode))
return traceno;
}
lua_assert(0);
return 0;
}
#endif
/* A trace exited. Restore interpreter state. */
int LJ_FASTCALL lj_trace_exit(jit_State *J, void *exptr)
{
ERRNO_SAVE
lua_State *L = J->L;
ExitState *ex = (ExitState *)exptr;
ExitDataCP exd;
int errcode;
const BCIns *pc;
void *cf;
GCtrace *T;
#ifdef EXITSTATE_PCREG
J->parent = trace_exit_find(J, (MCode *)(intptr_t)ex->gpr[EXITSTATE_PCREG]);
#endif
T = traceref(J, J->parent); UNUSED(T);
#ifdef EXITSTATE_CHECKEXIT
if (J->exitno == T->nsnap) { /* Treat stack check like a parent exit. */
lua_assert(T->root != 0);
J->exitno = T->ir[REF_BASE].op2;
J->parent = T->ir[REF_BASE].op1;
T = traceref(J, J->parent);
}
#endif
lua_assert(T != NULL && J->exitno < T->nsnap);
exd.J = J;
exd.exptr = exptr;
errcode = lj_vm_cpcall(L, NULL, &exd, trace_exit_cp);
if (errcode)
return -errcode; /* Return negated error code. */
lj_vmevent_send(L, TEXIT,
lj_state_checkstack(L, 4+RID_NUM_GPR+RID_NUM_FPR+LUA_MINSTACK);
setintV(L->top++, J->parent);
setintV(L->top++, J->exitno);
trace_exit_regs(L, ex);
);
pc = exd.pc;
cf = cframe_raw(L->cframe);
setcframe_pc(cf, pc);
if (G(L)->gc.state == GCSatomic || G(L)->gc.state == GCSfinalize) {
if (!(G(L)->hookmask & HOOK_GC))
lj_gc_step(L); /* Exited because of GC: drive GC forward. */
} else {
trace_hotside(J, pc);
}
if (bc_op(*pc) == BC_JLOOP) {
BCIns *retpc = &traceref(J, bc_d(*pc))->startins;
if (bc_isret(bc_op(*retpc))) {
if (J->state == LJ_TRACE_RECORD) {
J->patchins = *pc;
J->patchpc = (BCIns *)pc;
*J->patchpc = *retpc;
J->bcskip = 1;
} else {
pc = retpc;
setcframe_pc(cf, pc);
}
}
}
/* Return MULTRES or 0. */
ERRNO_RESTORE
switch (bc_op(*pc)) {
case BC_CALLM: case BC_CALLMT:
return (int)((BCReg)(L->top - L->base) - bc_a(*pc) - bc_c(*pc));
case BC_RETM:
return (int)((BCReg)(L->top - L->base) + 1 - bc_a(*pc) - bc_d(*pc));
case BC_TSETM:
return (int)((BCReg)(L->top - L->base) + 1 - bc_a(*pc));
default:
if (bc_op(*pc) >= BC_FUNCF)
return (int)((BCReg)(L->top - L->base) + 1);
return 0;
}
}
#endif
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