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mirror of https://github.com/golang/go synced 2024-11-18 23:34:45 -07:00

runtime: move finalizer thread to Go.

LGTM=dvyukov
R=golang-codereviews, dvyukov, khr
CC=golang-codereviews
https://golang.org/cl/124630043
This commit is contained in:
Keith Randall 2014-08-28 13:23:10 -07:00
parent e66ff2b908
commit c46bcd4d13
9 changed files with 303 additions and 284 deletions

View File

@ -154,7 +154,6 @@ static void
printtypename(Type *t)
{
Sym *s;
Type *t1;
int w;
char *n;
@ -228,19 +227,8 @@ printtypename(Type *t)
Bprint(&outbuf, "%U", n);
break;
case TFUNC:
Bprint(&outbuf, "func(");
for(t1 = t->down; t1 != T; t1 = t1->down) {
if(t1->etype == TVOID)
break;
if(t1 != t->down)
Bprint(&outbuf, ", ");
printtypename(t1);
}
Bprint(&outbuf, ")");
if(t->link && t->link->etype != TVOID) {
Bprint(&outbuf, " ");
printtypename(t->link);
}
// There's no equivalent to a C function in the Go world.
Bprint(&outbuf, "unsafe.Pointer");
break;
case TDOT:
Bprint(&outbuf, "...interface{}");

View File

@ -97,8 +97,7 @@ search:
t := (*method)(add(unsafe.Pointer(x), unsafe.Sizeof(uncommontype{})+uintptr(j)*unsafe.Sizeof(method{})))
if t.mtyp == itype && t.name == iname && t.pkgpath == ipkgpath {
if m != nil {
f := (*func())(add(unsafe.Pointer(m), unsafe.Sizeof(itab{})+uintptr(k)*ptrSize))
*f = t.ifn
*(*unsafe.Pointer)(add(unsafe.Pointer(m), unsafe.Sizeof(itab{})+uintptr(k)*ptrSize)) = t.ifn
}
goto nextimethod
}

View File

@ -423,107 +423,36 @@ runtime·cnewarray(Type *typ, intgo n)
return cnew(typ, n);
}
static void
setFinalizer(Eface obj, Eface finalizer)
{
byte *base;
uintptr size;
FuncType *ft;
int32 i;
uintptr nret;
Type *t;
Type *fint;
PtrType *ot;
Iface iface;
if(obj.type == nil) {
runtime·printf("runtime.SetFinalizer: first argument is nil interface\n");
goto throw;
}
if((obj.type->kind&KindMask) != KindPtr) {
runtime·printf("runtime.SetFinalizer: first argument is %S, not pointer\n", *obj.type->string);
goto throw;
}
ot = (PtrType*)obj.type;
// As an implementation detail we do not run finalizers for zero-sized objects,
// because we use &runtime·zerobase for all such allocations.
if(ot->elem != nil && ot->elem->size == 0)
return;
// The following check is required for cases when a user passes a pointer to composite literal,
// but compiler makes it a pointer to global. For example:
// var Foo = &Object{}
// func main() {
// runtime.SetFinalizer(Foo, nil)
// }
// See issue 7656.
if((byte*)obj.data < runtime·mheap.arena_start || runtime·mheap.arena_used <= (byte*)obj.data)
return;
if(!runtime·mlookup(obj.data, &base, &size, nil) || obj.data != base) {
// As an implementation detail we allow to set finalizers for an inner byte
// of an object if it could come from tiny alloc (see mallocgc for details).
if(ot->elem == nil || (ot->elem->kind&KindNoPointers) == 0 || ot->elem->size >= TinySize) {
runtime·printf("runtime.SetFinalizer: pointer not at beginning of allocated block (%p)\n", obj.data);
goto throw;
}
}
if(finalizer.type != nil) {
runtime·createfing();
if((finalizer.type->kind&KindMask) != KindFunc)
goto badfunc;
ft = (FuncType*)finalizer.type;
if(ft->dotdotdot || ft->in.len != 1)
goto badfunc;
fint = *(Type**)ft->in.array;
if(fint == obj.type) {
// ok - same type
} else if((fint->kind&KindMask) == KindPtr && (fint->x == nil || fint->x->name == nil || obj.type->x == nil || obj.type->x->name == nil) && ((PtrType*)fint)->elem == ((PtrType*)obj.type)->elem) {
// ok - not same type, but both pointers,
// one or the other is unnamed, and same element type, so assignable.
} else if((fint->kind&KindMask) == KindInterface && ((InterfaceType*)fint)->mhdr.len == 0) {
// ok - satisfies empty interface
} else if((fint->kind&KindMask) == KindInterface && runtime·ifaceE2I2((InterfaceType*)fint, obj, &iface)) {
// ok - satisfies non-empty interface
} else
goto badfunc;
// compute size needed for return parameters
nret = 0;
for(i=0; i<ft->out.len; i++) {
t = ((Type**)ft->out.array)[i];
nret = ROUND(nret, t->align) + t->size;
}
nret = ROUND(nret, sizeof(void*));
ot = (PtrType*)obj.type;
if(!runtime·addfinalizer(obj.data, finalizer.data, nret, fint, ot)) {
runtime·printf("runtime.SetFinalizer: finalizer already set\n");
goto throw;
}
} else {
// NOTE: asking to remove a finalizer when there currently isn't one set is OK.
runtime·removefinalizer(obj.data);
}
return;
badfunc:
runtime·printf("runtime.SetFinalizer: cannot pass %S to finalizer %S\n", *obj.type->string, *finalizer.type->string);
throw:
runtime·throw("runtime.SetFinalizer");
}
void
runtime·setFinalizer_m(void)
{
Eface obj, finalizer;
FuncVal *fn;
void *arg;
uintptr nret;
Type *fint;
PtrType *ot;
obj.type = g->m->ptrarg[0];
obj.data = g->m->ptrarg[1];
finalizer.type = g->m->ptrarg[2];
finalizer.data = g->m->ptrarg[3];
fn = g->m->ptrarg[0];
arg = g->m->ptrarg[1];
nret = g->m->scalararg[0];
fint = g->m->ptrarg[2];
ot = g->m->ptrarg[3];
g->m->ptrarg[0] = nil;
g->m->ptrarg[1] = nil;
g->m->ptrarg[2] = nil;
g->m->ptrarg[3] = nil;
setFinalizer(obj, finalizer);
g->m->scalararg[0] = runtime·addfinalizer(arg, fn, nret, fint, ot);
}
void
runtime·removeFinalizer_m(void)
{
void *p;
p = g->m->ptrarg[0];
g->m->ptrarg[0] = nil;
runtime·removefinalizer(p);
}
// mcallable cache refill

View File

@ -35,6 +35,8 @@ const (
bitBoundary = 1
bitMarked = 2
bitMask = bitBoundary | bitMarked
mSpanInUse = 0
)
// Page number (address>>pageShift)
@ -539,27 +541,239 @@ func GC() {
// If a finalizer must run for a long time, it should do so by starting
// a new goroutine.
func SetFinalizer(obj interface{}, finalizer interface{}) {
// We do just enough work here to make the mcall type safe.
// The rest is done on the M stack.
e := (*eface)(unsafe.Pointer(&obj))
typ := e._type
if typ == nil {
etyp := e._type
if etyp == nil {
gothrow("runtime.SetFinalizer: first argument is nil")
}
if typ.kind&kindMask != kindPtr {
gothrow("runtime.SetFinalizer: first argument is " + *typ._string + ", not pointer")
if etyp.kind&kindMask != kindPtr {
gothrow("runtime.SetFinalizer: first argument is " + *etyp._string + ", not pointer")
}
ot := (*ptrtype)(unsafe.Pointer(etyp))
if ot.elem == nil {
gothrow("nil elem type!")
}
// As an implementation detail we do not run finalizers for zero-sized objects,
// because we use &runtime·zerobase for all such allocations.
if ot.elem.size == 0 {
return
}
// find the containing object
_, base, _ := findObject(e.data)
// The following check is required for cases when a user passes a pointer to composite
// literal, but compiler makes it a pointer to global. For example:
// var Foo = &Object{}
// func main() {
// runtime.SetFinalizer(Foo, nil)
// }
// See issue 7656.
if base == nil {
return
}
if e.data != base {
// As an implementation detail we allow to set finalizers for an inner byte
// of an object if it could come from tiny alloc (see mallocgc for details).
if ot.elem == nil || ot.elem.kind&kindNoPointers == 0 || ot.elem.size >= maxTinySize {
gothrow("runtime.SetFinalizer: pointer not at beginning of allocated block")
}
}
f := (*eface)(unsafe.Pointer(&finalizer))
ftyp := f._type
if ftyp != nil && ftyp.kind&kindMask != kindFunc {
if ftyp == nil {
// switch to M stack and remove finalizer
mp := acquirem()
mp.ptrarg[0] = e.data
onM(&removeFinalizer_m)
releasem(mp)
return
}
if ftyp.kind&kindMask != kindFunc {
gothrow("runtime.SetFinalizer: second argument is " + *ftyp._string + ", not a function")
}
ft := (*functype)(unsafe.Pointer(ftyp))
ins := *(*[]*_type)(unsafe.Pointer(&ft.in))
if ft.dotdotdot || len(ins) != 1 {
gothrow("runtime.SetFinalizer: cannot pass " + *etyp._string + " to finalizer " + *ftyp._string)
}
fint := ins[0]
switch {
case fint == etyp:
// ok - same type
goto okarg
case fint.kind&kindMask == kindPtr:
if (fint.x == nil || fint.x.name == nil || etyp.x == nil || etyp.x.name == nil) && (*ptrtype)(unsafe.Pointer(fint)).elem == ot.elem {
// ok - not same type, but both pointers,
// one or the other is unnamed, and same element type, so assignable.
goto okarg
}
case fint.kind&kindMask == kindInterface:
ityp := (*interfacetype)(unsafe.Pointer(fint))
if len(ityp.mhdr) == 0 {
// ok - satisfies empty interface
goto okarg
}
if _, ok := assertE2I2(ityp, obj); ok {
goto okarg
}
}
gothrow("runtime.SetFinalizer: cannot pass " + *etyp._string + " to finalizer " + *ftyp._string)
okarg:
// compute size needed for return parameters
nret := uintptr(0)
for _, t := range *(*[]*_type)(unsafe.Pointer(&ft.out)) {
nret = round(nret, uintptr(t.align)) + uintptr(t.size)
}
nret = round(nret, ptrSize)
// make sure we have a finalizer goroutine
createfing()
// switch to M stack to add finalizer record
mp := acquirem()
mp.ptrarg[0] = unsafe.Pointer(typ)
mp.ptrarg[0] = f.data
mp.ptrarg[1] = e.data
mp.ptrarg[2] = unsafe.Pointer(ftyp)
mp.ptrarg[3] = f.data
mp.scalararg[0] = nret
mp.ptrarg[2] = unsafe.Pointer(fint)
mp.ptrarg[3] = unsafe.Pointer(ot)
onM(&setFinalizer_m)
if mp.scalararg[0] != 1 {
gothrow("runtime.SetFinalizer: finalizer already set")
}
releasem(mp)
}
// round n up to a multiple of a. a must be a power of 2.
func round(n, a uintptr) uintptr {
return (n + a - 1) &^ (a - 1)
}
// Look up pointer v in heap. Return the span containing the object,
// the start of the object, and the size of the object. If the object
// does not exist, return nil, nil, 0.
func findObject(v unsafe.Pointer) (s *mspan, x unsafe.Pointer, n uintptr) {
c := gomcache()
c.local_nlookup++
if ptrSize == 4 && c.local_nlookup >= 1<<30 {
// purge cache stats to prevent overflow
lock(&mheap_.lock)
purgecachedstats(c)
unlock(&mheap_.lock)
}
// find span
arena_start := uintptr(unsafe.Pointer(mheap_.arena_start))
arena_used := uintptr(unsafe.Pointer(mheap_.arena_used))
if uintptr(v) < arena_start || uintptr(v) >= arena_used {
return
}
p := uintptr(v) >> pageShift
q := p - arena_start>>pageShift
s = *(**mspan)(add(unsafe.Pointer(mheap_.spans), q*ptrSize))
if s == nil {
return
}
x = unsafe.Pointer(uintptr(s.start) << pageShift)
if uintptr(v) < uintptr(x) || uintptr(v) >= uintptr(unsafe.Pointer(s.limit)) || s.state != mSpanInUse {
s = nil
x = nil
return
}
n = uintptr(s.elemsize)
if s.sizeclass != 0 {
x = add(x, (uintptr(v)-uintptr(x))/n*n)
}
return
}
var fingCreate uint32
func createfing() {
// start the finalizer goroutine exactly once
if fingCreate == 0 && cas(&fingCreate, 0, 1) {
go runfinq()
}
}
// This is the goroutine that runs all of the finalizers
func runfinq() {
var (
frame unsafe.Pointer
framecap uintptr
)
for {
lock(&finlock)
fb := finq
finq = nil
if fb == nil {
gp := getg()
fing = gp
fingwait = true
gp.issystem = true
goparkunlock(&finlock, "finalizer wait")
gp.issystem = false
continue
}
unlock(&finlock)
if raceenabled {
racefingo()
}
for fb != nil {
for i := int32(0); i < fb.cnt; i++ {
f := (*finalizer)(add(unsafe.Pointer(&fb.fin), uintptr(i)*unsafe.Sizeof(finalizer{})))
framesz := unsafe.Sizeof((interface{})(nil)) + uintptr(f.nret)
if framecap < framesz {
// The frame does not contain pointers interesting for GC,
// all not yet finalized objects are stored in finq.
// If we do not mark it as FlagNoScan,
// the last finalized object is not collected.
frame = gomallocgc(framesz, nil, flagNoScan)
framecap = framesz
}
if f.fint == nil {
gothrow("missing type in runfinq")
}
switch f.fint.kind & kindMask {
case kindPtr:
// direct use of pointer
*(*unsafe.Pointer)(frame) = f.arg
case kindInterface:
ityp := (*interfacetype)(unsafe.Pointer(f.fint))
// set up with empty interface
(*eface)(frame)._type = &f.ot.typ
(*eface)(frame).data = f.arg
if len(ityp.mhdr) != 0 {
// convert to interface with methods
// this conversion is guaranteed to succeed - we checked in SetFinalizer
*(*fInterface)(frame) = assertE2I(ityp, *(*interface{})(frame))
}
default:
gothrow("bad kind in runfinq")
}
reflectcall(unsafe.Pointer(f.fn), frame, uint32(framesz), uint32(framesz))
// drop finalizer queue references to finalized object
f.fn = nil
f.arg = nil
f.ot = nil
}
fb.cnt = 0
next := fb.next
lock(&finlock)
fb.next = finc
finc = fb
unlock(&finlock)
fb = next
}
}
}

View File

@ -551,9 +551,32 @@ void runtime·gchelper(void);
void runtime·createfing(void);
G* runtime·wakefing(void);
void runtime·getgcmask(byte*, Type*, byte**, uintptr*);
typedef struct Finalizer Finalizer;
struct Finalizer
{
FuncVal *fn; // function to call
void *arg; // ptr to object
uintptr nret; // bytes of return values from fn
Type *fint; // type of first argument of fn
PtrType *ot; // type of ptr to object
};
typedef struct FinBlock FinBlock;
struct FinBlock
{
FinBlock *alllink;
FinBlock *next;
int32 cnt;
int32 cap;
Finalizer fin[1];
};
extern Mutex runtime·finlock; // protects the following variables
extern G* runtime·fing;
extern bool runtime·fingwait;
extern bool runtime·fingwake;
extern FinBlock *runtime·finq; // list of finalizers that are to be executed
extern FinBlock *runtime·finc; // cache of free blocks
void runtime·setprofilebucket(void *p, Bucket *b);

View File

@ -138,26 +138,6 @@ struct Workbuf
byte* obj[(WorkbufSize-sizeof(LFNode)-sizeof(uintptr))/PtrSize];
};
typedef struct Finalizer Finalizer;
struct Finalizer
{
FuncVal *fn;
void *arg;
uintptr nret;
Type *fint;
PtrType *ot;
};
typedef struct FinBlock FinBlock;
struct FinBlock
{
FinBlock *alllink;
FinBlock *next;
int32 cnt;
int32 cap;
Finalizer fin[1];
};
extern byte runtime·data[];
extern byte runtime·edata[];
extern byte runtime·bss[];
@ -166,18 +146,19 @@ extern byte runtime·ebss[];
extern byte runtime·gcdata[];
extern byte runtime·gcbss[];
static Mutex finlock; // protects the following variables
static FinBlock *finq; // list of finalizers that are to be executed
static FinBlock *finc; // cache of free blocks
static FinBlock *allfin; // list of all blocks
Mutex runtime·finlock; // protects the following variables
G* runtime·fing; // goroutine that runs finalizers
FinBlock* runtime·finq; // list of finalizers that are to be executed
FinBlock* runtime·finc; // cache of free blocks
bool runtime·fingwait;
bool runtime·fingwake;
static FinBlock *allfin; // list of all blocks
BitVector runtime·gcdatamask;
BitVector runtime·gcbssmask;
static Mutex gclock;
static void runfinq(void);
static void bgsweep(void);
static Workbuf* getempty(Workbuf*);
static Workbuf* getfull(Workbuf*);
@ -189,7 +170,6 @@ static bool scanframe(Stkframe *frame, void *unused);
static void scanstack(G *gp);
static BitVector unrollglobgcprog(byte *prog, uintptr size);
static FuncVal runfinqv = {runfinq};
static FuncVal bgsweepv = {bgsweep};
static struct {
@ -804,28 +784,28 @@ runtime·queuefinalizer(byte *p, FuncVal *fn, uintptr nret, Type *fint, PtrType
FinBlock *block;
Finalizer *f;
runtime·lock(&finlock);
if(finq == nil || finq->cnt == finq->cap) {
if(finc == nil) {
finc = runtime·persistentalloc(FinBlockSize, 0, &mstats.gc_sys);
finc->cap = (FinBlockSize - sizeof(FinBlock)) / sizeof(Finalizer) + 1;
finc->alllink = allfin;
allfin = finc;
runtime·lock(&runtime·finlock);
if(runtime·finq == nil || runtime·finq->cnt == runtime·finq->cap) {
if(runtime·finc == nil) {
runtime·finc = runtime·persistentalloc(FinBlockSize, 0, &mstats.gc_sys);
runtime·finc->cap = (FinBlockSize - sizeof(FinBlock)) / sizeof(Finalizer) + 1;
runtime·finc->alllink = allfin;
allfin = runtime·finc;
}
block = finc;
finc = block->next;
block->next = finq;
finq = block;
block = runtime·finc;
runtime·finc = block->next;
block->next = runtime·finq;
runtime·finq = block;
}
f = &finq->fin[finq->cnt];
finq->cnt++;
f = &runtime·finq->fin[runtime·finq->cnt];
runtime·finq->cnt++;
f->fn = fn;
f->nret = nret;
f->fint = fint;
f->ot = ot;
f->arg = p;
runtime·fingwake = true;
runtime·unlock(&finlock);
runtime·unlock(&runtime·finlock);
}
void
@ -1624,141 +1604,19 @@ gchelperstart(void)
runtime·throw("gchelper not running on g0 stack");
}
static void
runfinq(void)
{
Finalizer *f;
FinBlock *fb, *next;
byte *frame;
uint32 framesz, framecap, i;
Eface *ef, ef1;
// This function blocks for long periods of time, and because it is written in C
// we have no liveness information. Zero everything so that uninitialized pointers
// do not cause memory leaks.
f = nil;
fb = nil;
next = nil;
frame = nil;
framecap = 0;
framesz = 0;
i = 0;
ef = nil;
ef1.type = nil;
ef1.data = nil;
// force flush to memory
USED(&f);
USED(&fb);
USED(&next);
USED(&framesz);
USED(&i);
USED(&ef);
USED(&ef1);
for(;;) {
runtime·lock(&finlock);
fb = finq;
finq = nil;
if(fb == nil) {
runtime·fingwait = true;
g->issystem = true;
runtime·parkunlock(&finlock, runtime·gostringnocopy((byte*)"finalizer wait"));
g->issystem = false;
continue;
}
runtime·unlock(&finlock);
if(raceenabled)
runtime·racefingo();
for(; fb; fb=next) {
next = fb->next;
for(i=0; i<fb->cnt; i++) {
f = &fb->fin[i];
framesz = sizeof(Eface) + f->nret;
if(framecap < framesz) {
// The frame does not contain pointers interesting for GC,
// all not yet finalized objects are stored in finq.
// If we do not mark it as FlagNoScan,
// the last finalized object is not collected.
frame = runtime·mallocgc(framesz, 0, FlagNoScan);
framecap = framesz;
}
if(f->fint == nil)
runtime·throw("missing type in runfinq");
if((f->fint->kind&KindMask) == KindPtr) {
// direct use of pointer
*(void**)frame = f->arg;
} else if(((InterfaceType*)f->fint)->mhdr.len == 0) {
// convert to empty interface
ef = (Eface*)frame;
ef->type = &f->ot->typ;
ef->data = f->arg;
} else {
// convert to interface with methods, via empty interface.
ef1.type = &f->ot->typ;
ef1.data = f->arg;
if(!runtime·ifaceE2I2((InterfaceType*)f->fint, ef1, (Iface*)frame))
runtime·throw("invalid type conversion in runfinq");
}
reflect·call(f->fn, frame, framesz, framesz);
f->fn = nil;
f->arg = nil;
f->ot = nil;
}
fb->cnt = 0;
runtime·lock(&finlock);
fb->next = finc;
finc = fb;
runtime·unlock(&finlock);
}
// Zero everything that's dead, to avoid memory leaks.
// See comment at top of function.
f = nil;
fb = nil;
next = nil;
i = 0;
ef = nil;
ef1.type = nil;
ef1.data = nil;
runtime·gc(1); // trigger another gc to clean up the finalized objects, if possible
}
}
void
runtime·createfing(void)
{
if(runtime·fing != nil)
return;
// Here we use gclock instead of finlock,
// because newproc1 can allocate, which can cause on-demand span sweep,
// which can queue finalizers, which would deadlock.
runtime·lock(&gclock);
if(runtime·fing == nil)
runtime·fing = runtime·newproc1(&runfinqv, nil, 0, 0, runtime·gc);
runtime·unlock(&gclock);
}
void
runtime·createfingM(G *gp)
{
runtime·createfing();
runtime·gogo(&gp->sched);
}
G*
runtime·wakefing(void)
{
G *res;
res = nil;
runtime·lock(&finlock);
runtime·lock(&runtime·finlock);
if(runtime·fingwait && runtime·fingwake) {
runtime·fingwait = false;
runtime·fingwake = false;
res = runtime·fing;
}
runtime·unlock(&finlock);
runtime·unlock(&runtime·finlock);
return res;
}

View File

@ -50,7 +50,7 @@ func gopark(unlockf unsafe.Pointer, lock unsafe.Pointer, reason string) {
gothrow("gopark: bad g status")
}
mp.waitlock = lock
mp.waitunlockf = *(*func(*g, unsafe.Pointer) bool)(unsafe.Pointer(&unlockf))
mp.waitunlockf = unlockf
gp.waitreason = reason
releasem(mp)
// can't do anything that might move the G between Ms here.

View File

@ -39,6 +39,8 @@ func raceacquireg(gp *g, addr unsafe.Pointer)
//go:noescape
func racereleaseg(gp *g, addr unsafe.Pointer)
func racefingo()
// Should be a built-in for unsafe.Pointer?
func add(p unsafe.Pointer, x uintptr) unsafe.Pointer {
return unsafe.Pointer(uintptr(p) + x)
@ -77,6 +79,7 @@ var (
mprofMalloc_m,
gc_m,
setFinalizer_m,
removeFinalizer_m,
markallocated_m,
unrollgcprog_m,
unrollgcproginplace_m,
@ -187,6 +190,7 @@ func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) uns
func munmap(addr unsafe.Pointer, n uintptr)
func madvise(addr unsafe.Pointer, n uintptr, flags int32)
func newstackcall(fv *funcval, addr unsafe.Pointer, size uint32)
func reflectcall(fn, arg unsafe.Pointer, n uint32, retoffset uint32)
func procyield(cycles uint32)
func osyield()
func cgocallback_gofunc(fv *funcval, frame unsafe.Pointer, framesize uintptr)
@ -199,6 +203,7 @@ func notesleep(n *note)
func noteclear(n *note)
func lock(lk *mutex)
func unlock(lk *mutex)
func purgecachedstats(c *mcache)
//go:noescape
func cas(ptr *uint32, old, new uint32) bool

View File

@ -49,3 +49,6 @@ TEXT runtimepprof·runtime_cyclesPerSecond(SB),NOSPLIT,$0-0
TEXT bytes·Compare(SB),NOSPLIT,$0-0
JMP runtime·cmpbytes(SB)
TEXT runtime·reflectcall(SB), NOSPLIT, $0-0
JMP reflect·call(SB)