Fix trace stitching by storing trace object itself in the continuation.

This commit is contained in:
Vyacheslav Egorov 2015-08-26 02:54:34 +02:00
parent ca7888944e
commit 9396a47a3b
10 changed files with 65 additions and 80 deletions

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@ -96,18 +96,10 @@ static ptrdiff_t results_wanted(jit_State *J)
return -1;
}
#ifdef LUAJIT_TRACE_STITCHING
/* This feature is disabled for now due to a design mistake. Sorry.
**
** It causes unpredictable behavior and crashes when a full trace flush
** happens with a stitching continuation still in the stack somewhere.
*/
/* Trace stitching: add continuation below frame to start a new trace. */
static void recff_stitch(jit_State *J)
{
ASMFunction cont = lj_cont_stitch;
TraceNo traceno = J->cur.traceno;
lua_State *L = J->L;
TValue *base = L->base;
const BCIns *pc = frame_pc(base-1);
@ -120,7 +112,7 @@ static void recff_stitch(jit_State *J)
setframe_ftsz(base+1, ((char *)(base+1) - (char *)pframe) + FRAME_CONT);
setcont(base, cont);
setframe_pc(base, pc);
if (LJ_DUALNUM) setintV(base-1, traceno); else base[-1].u64 = traceno;
setnilV(base-1);
L->base += 2;
L->top += 2;
@ -131,8 +123,9 @@ static void recff_stitch(jit_State *J)
#else
trcont = lj_ir_kptr(J, (void *)cont);
#endif
J->selfref = lj_ir_k64_reserve(J);
J->base[0] = trcont | TREF_CONT;
J->base[-1] = LJ_DUALNUM ? lj_ir_kint(J,traceno) : lj_ir_knum_u64(J,traceno);
J->base[-1] = emitir(IRT(IR_XLOAD, IRT_P64), lj_ir_kptr(J, J->selfref), 0);
J->base += 2;
J->baseslot += 2;
J->framedepth++;
@ -181,31 +174,6 @@ static void LJ_FASTCALL recff_nyi(jit_State *J, RecordFFData *rd)
/* Must stop the trace for classic C functions with arbitrary side-effects. */
#define recff_c recff_nyi
#else
/* Fallback handler for fast functions that are not recorded (yet). */
static void LJ_FASTCALL recff_nyi(jit_State *J, RecordFFData *rd)
{
setfuncV(J->L, &J->errinfo, J->fn);
lj_trace_err_info(J, LJ_TRERR_NYIFF);
UNUSED(rd);
}
/* Throw error for unsupported variant of fast function. */
LJ_NORET static void recff_nyiu(jit_State *J, RecordFFData *rd)
{
setfuncV(J->L, &J->errinfo, J->fn);
lj_trace_err_info(J, LJ_TRERR_NYIFFU);
UNUSED(rd);
}
/* Must abort the trace for classic C functions with arbitrary side-effects. */
static void LJ_FASTCALL recff_c(jit_State *J, RecordFFData *rd)
{
setfuncV(J->L, &J->errinfo, J->fn);
lj_trace_err_info(J, LJ_TRERR_NYICF);
UNUSED(rd);
}
#endif
/* Emit BUFHDR for the global temporary buffer. */
static TRef recff_bufhdr(jit_State *J)

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@ -69,6 +69,10 @@ static void gc_mark(global_State *g, GCobj *o)
gray2black(o); /* Closed upvalues are never gray. */
} else if (gct != ~LJ_TSTR && gct != ~LJ_TCDATA) {
lua_assert(gct == ~LJ_TFUNC || gct == ~LJ_TTAB ||
#if LJ_HASJIT
/* Can occur as a part of trace stitching continuation. */
gct == ~LJ_TTRACE ||
#endif
gct == ~LJ_TTHREAD || gct == ~LJ_TPROTO);
setgcrefr(o->gch.gclist, g->gc.gray);
setgcref(g->gc.gray, o);

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@ -209,13 +209,46 @@ void lj_ir_k64_freeall(jit_State *J)
lj_mem_free(J2G(J), k, sizeof(K64Array));
k = next;
}
setmref(J->k64, NULL);
}
/* Add 64 bit constant to the last K64Array or add a new array. */
static TValue *ir_k64_add(jit_State *J, K64Array *kl, uint64_t u64)
{
TValue *ntv;
/* Constant was not found, need to add it. */
if (!(kl && kl->numk < LJ_MIN_K64SZ)) { /* Allocate a new array. */
K64Array *kn = lj_mem_newt(J->L, sizeof(K64Array), K64Array);
setmref(kn->next, NULL);
kn->numk = 0;
if (kl)
setmref(kl->next, kn); /* Chain to the end of the list. */
else
setmref(J->k64, kn); /* Link first array. */
kl = kn;
}
ntv = &kl->k[kl->numk++]; /* Add to current array. */
ntv->u64 = u64;
return ntv;
}
/* Reserve space for a 64 bit constant in chained array. */
TValue *lj_ir_k64_reserve(jit_State *J)
{
K64Array *k, *kl = NULL;
/* Intern 0 to ensure that no code can by mistake reuse mutable slot. */
lj_ir_k64_find(J, 0);
/* Search for the last element in the chain of arrays. */
for (k = mref(J->k64, K64Array); k; k = mref(k->next, K64Array)) {
kl = k;
}
return ir_k64_add(J, kl, 0);
}
/* Find 64 bit constant in chained array or add it. */
cTValue *lj_ir_k64_find(jit_State *J, uint64_t u64)
{
K64Array *k, *kp = NULL;
TValue *ntv;
MSize idx;
/* Search for the constant in the whole chain of arrays. */
for (k = mref(J->k64, K64Array); k; k = mref(k->next, K64Array)) {
@ -226,20 +259,7 @@ cTValue *lj_ir_k64_find(jit_State *J, uint64_t u64)
return tv;
}
}
/* Constant was not found, need to add it. */
if (!(kp && kp->numk < LJ_MIN_K64SZ)) { /* Allocate a new array. */
K64Array *kn = lj_mem_newt(J->L, sizeof(K64Array), K64Array);
setmref(kn->next, NULL);
kn->numk = 0;
if (kp)
setmref(kp->next, kn); /* Chain to the end of the list. */
else
setmref(J->k64, kn); /* Link first array. */
kp = kn;
}
ntv = &kp->k[kp->numk++]; /* Add to current array. */
ntv->u64 = u64;
return ntv;
return ir_k64_add(J, kp, u64);
}
/* Intern 64 bit constant, given by its address. */

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@ -40,6 +40,7 @@ static LJ_AINLINE IRRef lj_ir_nextins(jit_State *J)
LJ_FUNC TRef LJ_FASTCALL lj_ir_kint(jit_State *J, int32_t k);
LJ_FUNC void lj_ir_k64_freeall(jit_State *J);
LJ_FUNC TRef lj_ir_k64(jit_State *J, IROp op, cTValue *tv);
LJ_FUNC TValue *lj_ir_k64_reserve(jit_State *J);
LJ_FUNC cTValue *lj_ir_k64_find(jit_State *J, uint64_t u64);
LJ_FUNC TRef lj_ir_knum_u64(jit_State *J, uint64_t u64);
LJ_FUNC TRef lj_ir_knumint(jit_State *J, lua_Number n);

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@ -418,6 +418,8 @@ typedef struct jit_State {
TValue errinfo; /* Additional info element for trace errors. */
TValue* selfref; /* Slot for the trace self reference. */
#if LJ_HASPROFILE
GCproto *prev_pt; /* Previous prototype. */
BCLine prev_line; /* Previous line. */

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@ -274,7 +274,7 @@ int lj_trace_flushall(lua_State *L)
if (T->root == 0)
trace_flushroot(J, T);
lj_gdbjit_deltrace(J, T);
T->traceno = 0;
T->traceno = T->link = 0; /* Blacklist the link for cont_stitch. */
setgcrefnull(J->trace[i]);
}
}
@ -284,6 +284,7 @@ int lj_trace_flushall(lua_State *L)
memset(J->penalty, 0, sizeof(J->penalty));
/* Free the whole machine code and invalidate all exit stub groups. */
lj_mcode_free(J);
lj_ir_k64_freeall(J);
memset(J->exitstubgroup, 0, sizeof(J->exitstubgroup));
lj_vmevent_send(L, TRACE,
setstrV(L, L->top++, lj_str_newlit(L, "flush"));
@ -403,6 +404,7 @@ static void trace_start(jit_State *J)
lj_resetsplit(J);
J->retryrec = 0;
setgcref(J->cur.startpt, obj2gco(J->pt));
J->selfref = NULL;
L = J->L;
lj_vmevent_send(L, TRACE,
@ -426,7 +428,7 @@ static void trace_stop(jit_State *J)
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;
lua_State *L = J->L;
switch (op) {
case BC_FORL:
@ -477,8 +479,10 @@ static void trace_stop(jit_State *J)
lj_mcode_commit(J, J->cur.mcode);
J->postproc = LJ_POST_NONE;
trace_save(J, T);
if (J->cur.linktype == LJ_TRLINK_STITCH) {
setgcV(L, J->selfref, obj2gco(T), LJ_TTRACE);
}
L = J->L;
lj_vmevent_send(L, TRACE,
setstrV(L, L->top++, lj_str_newlit(L, "stop"));
setintV(L->top++, traceno);

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@ -2086,7 +2086,7 @@ static void build_subroutines(BuildCtx *ctx)
| // RA = resultptr, CARG4 = meta base
| ldr RB, SAVE_MULTRES
| ldr INS, [PC, #-4]
| ldr CARG3, [CARG4, #-24] // Save previous trace number.
| ldr TRACE:CARG3, [CARG4, #-24] // Save previous trace.
| subs RB, RB, #8
| decode_RA8 RC, INS // Call base.
| beq >2
@ -2101,23 +2101,20 @@ static void build_subroutines(BuildCtx *ctx)
| decode_RA8 RA, INS
| decode_RB8 RB, INS
| add RA, RA, RB
| ldr CARG1, [DISPATCH, #DISPATCH_J(trace)]
|3:
| cmp RA, RC
| mvn CARG2, #~LJ_TNIL
| bhi >9 // More results wanted?
|
| ldr TRACE:RA, [CARG1, CARG3, lsl #2]
| cmp TRACE:RA, #0
| beq ->cont_nop
| ldrh RC, TRACE:RA->link
| cmp RC, CARG3
| ldrh RA, TRACE:CARG3->traceno
| ldrh RC, TRACE:CARG3->link
| cmp RC, RA
| beq ->cont_nop // Blacklisted.
| cmp RC, #0
| bne =>BC_JLOOP // Jump to stitched trace.
|
| // Stitch a new trace to the previous trace.
| str CARG3, [DISPATCH, #DISPATCH_J(exitno)]
| str RA, [DISPATCH, #DISPATCH_J(exitno)]
| str L, [DISPATCH, #DISPATCH_J(L)]
| str BASE, L->base
| sub CARG1, DISPATCH, #-GG_DISP2J

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@ -2015,7 +2015,7 @@ static void build_subroutines(BuildCtx *ctx)
|.if JIT
| // RA = resultptr, RB = meta base
| lw INS, -4(PC)
| lw TMP3, -24+LO(RB) // Save previous trace number.
| lw TMP2, -24+LO(RB) // Save previous trace.
| decode_RA8a RC, INS
| addiu AT, MULTRES, -8
| decode_RA8b RC
@ -2034,17 +2034,13 @@ static void build_subroutines(BuildCtx *ctx)
| decode_RA8b RA
| decode_RB8b RB
| addu RA, RA, RB
| lw TMP1, DISPATCH_J(trace)(DISPATCH)
| addu RA, BASE, RA
|3:
| sltu AT, RC, RA
| bnez AT, >9 // More results wanted?
|. sll TMP2, TMP3, 2
|
| addu TMP2, TMP1, TMP2
| lw TRACE:TMP2, 0(TMP2)
| beqz TRACE:TMP2, ->cont_nop
|. nop
|
| lhu TMP3, TRACE:TMP2->traceno
| lhu RD, TRACE:TMP2->link
| beq RD, TMP3, ->cont_nop // Blacklisted.
|. load_got lj_dispatch_stitch

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@ -2525,7 +2525,7 @@ static void build_subroutines(BuildCtx *ctx)
|.if JIT
| // RA = resultptr, RB = meta base
| lwz INS, -4(PC)
| lwz TMP3, -20(RB) // Save previous trace number.
| lwz TRACE:TMP2, -20(RB) // Save previous trace.
| addic. TMP1, MULTRES, -8
| decode_RA8 RC, INS // Call base.
| beq >2
@ -2540,15 +2540,11 @@ static void build_subroutines(BuildCtx *ctx)
| decode_RA8 RA, INS
| decode_RB8 RB, INS
| add RA, RA, RB
| lwz TMP1, DISPATCH_J(trace)(DISPATCH)
|3:
| cmplw RA, RC
| bgt >9 // More results wanted?
|
| slwi TMP2, TMP3, 2
| lwzx TRACE:TMP2, TMP1, TMP2
| cmpwi TRACE:TMP2, 0
| beq ->cont_nop
| lhz TMP3, TRACE:TMP2->traceno
| lhz RD, TRACE:TMP2->link
| cmpw RD, TMP3
| cmpwi cr1, RD, 0

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@ -2667,7 +2667,7 @@ static void build_subroutines(BuildCtx *ctx)
|->cont_stitch: // Trace stitching.
|.if JIT
| // BASE = base, RC = result, RB = mbase
| mov RA, [RB-24] // Save previous trace number.
| mov RA, [RB-24] // Save previous trace.
| mov TMP1, RA
| mov TMP3, DISPATCH // Need one more register.
| mov DISPATCH, MULTRES
@ -2699,11 +2699,8 @@ static void build_subroutines(BuildCtx *ctx)
| ja >9 // More results wanted?
|
| mov DISPATCH, TMP3
| mov RB, TMP1 // Get previous trace number.
| mov RA, [DISPATCH+DISPATCH_J(trace)]
| mov TRACE:RD, [RA+RB*4]
| test TRACE:RD, TRACE:RD
| jz ->cont_nop
| mov TRACE:RD, TMP1 // Get previous trace.
| movzx RB, word TRACE:RD->traceno
| movzx RD, word TRACE:RD->link
| cmp RD, RB
| je ->cont_nop // Blacklisted.