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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runtime
#include "runtime.h"
#include "arch_GOARCH.h"
#include "type.h"
#include "typekind.h"
#include "malloc.h"
#include "../../cmd/ld/textflag.h"
func printiface(i Iface) {
runtime·printf("(%p,%p)", i.tab, i.data);
}
func printeface(e Eface) {
runtime·printf("(%p,%p)", e.type, e.data);
}
static Itab* hash[1009];
static Lock ifacelock;
static Itab*
itab(InterfaceType *inter, Type *type, int32 canfail)
{
int32 locked;
int32 ni;
Method *t, *et;
IMethod *i, *ei;
uint32 h;
String *iname, *ipkgPath;
Itab *m;
UncommonType *x;
Type *itype;
Eface err;
if(inter->mhdr.len == 0)
runtime·throw("internal error - misuse of itab");
locked = 0;
// easy case
x = type->x;
if(x == nil) {
if(canfail)
return nil;
iname = inter->m[0].name;
goto throw;
}
// compiler has provided some good hash codes for us.
h = inter->hash;
h += 17 * type->hash;
// TODO(rsc): h += 23 * x->mhash ?
h %= nelem(hash);
// look twice - once without lock, once with.
// common case will be no lock contention.
for(locked=0; locked<2; locked++) {
if(locked)
runtime·lock(&ifacelock);
for(m=runtime·atomicloadp(&hash[h]); m!=nil; m=m->link) {
if(m->inter == inter && m->type == type) {
if(m->bad) {
m = nil;
if(!canfail) {
// this can only happen if the conversion
// was already done once using the , ok form
// and we have a cached negative result.
// the cached result doesn't record which
// interface function was missing, so jump
// down to the interface check, which will
// do more work but give a better error.
goto search;
}
}
if(locked)
runtime·unlock(&ifacelock);
return m;
}
}
}
ni = inter->mhdr.len;
m = runtime·persistentalloc(sizeof(*m) + ni*sizeof m->fun[0], 0, &mstats.other_sys);
m->inter = inter;
m->type = type;
search:
// both inter and type have method sorted by name,
// and interface names are unique,
// so can iterate over both in lock step;
// the loop is O(ni+nt) not O(ni*nt).
i = inter->m;
ei = i + inter->mhdr.len;
t = x->m;
et = t + x->mhdr.len;
for(; i < ei; i++) {
itype = i->type;
iname = i->name;
ipkgPath = i->pkgPath;
for(;; t++) {
if(t >= et) {
if(!canfail) {
throw:
// didn't find method
runtime·newTypeAssertionError(
nil, type->string, inter->string,
iname, &err);
if(locked)
runtime·unlock(&ifacelock);
runtime·panic(err);
return nil; // not reached
}
m->bad = 1;
goto out;
}
if(t->mtyp == itype && t->name == iname && t->pkgPath == ipkgPath)
break;
}
if(m)
m->fun[i - inter->m] = t->ifn;
}
out:
if(!locked)
runtime·panicstring("invalid itab locking");
m->link = hash[h];
runtime·atomicstorep(&hash[h], m);
runtime·unlock(&ifacelock);
if(m->bad)
return nil;
return m;
}
// call the callback for every itab that is currently allocated.
void
runtime·iterate_itabs(void (*callback)(Itab*))
{
int32 i;
Itab *tab;
for(i = 0; i < nelem(hash); i++) {
for(tab = hash[i]; tab != nil; tab = tab->link) {
callback(tab);
}
}
}
static void
copyin(Type *t, void *src, void **dst)
{
uintptr size;
void *p;
Alg *alg;
size = t->size;
alg = t->alg;
if(size <= sizeof(*dst))
alg->copy(size, dst, src);
else {
p = runtime·cnew(t);
alg->copy(size, p, src);
*dst = p;
}
}
static void
copyout(Type *t, void **src, void *dst)
{
uintptr size;
Alg *alg;
size = t->size;
alg = t->alg;
if(size <= sizeof(*src))
alg->copy(size, dst, src);
else
alg->copy(size, dst, *src);
}
#pragma textflag NOSPLIT
func typ2Itab(t *Type, inter *InterfaceType, cache **Itab) (tab *Itab) {
tab = itab(inter, t, 0);
runtime·atomicstorep(cache, tab);
}
#pragma textflag NOSPLIT
func convT2I(t *Type, inter *InterfaceType, cache **Itab, elem *byte) (ret Iface) {
Itab *tab;
tab = runtime·atomicloadp(cache);
if(!tab) {
tab = itab(inter, t, 0);
runtime·atomicstorep(cache, tab);
}
ret.tab = tab;
copyin(t, elem, &ret.data);
}
#pragma textflag NOSPLIT
func convT2E(t *Type, elem *byte) (ret Eface) {
ret.type = t;
copyin(t, elem, &ret.data);
}
static void assertI2Tret(Type *t, Iface i, byte *ret);
/*
* NOTE: Cannot use 'func' here, because we have to declare
* a return value, the only types we have are at least 1 byte large,
* goc2c will zero the return value, and the actual return value
* might have size 0 bytes, in which case the zeroing of the
* 1 or more bytes would be wrong.
* Using C lets us control (avoid) the initial zeroing.
*/
#pragma textflag NOSPLIT
void
runtime·assertI2T(Type *t, Iface i, GoOutput retbase)
{
assertI2Tret(t, i, (byte*)&retbase);
}
static void
assertI2Tret(Type *t, Iface i, byte *ret)
{
Itab *tab;
Eface err;
tab = i.tab;
if(tab == nil) {
runtime·newTypeAssertionError(
nil, nil, t->string,
nil, &err);
runtime·panic(err);
}
if(tab->type != t) {
runtime·newTypeAssertionError(
tab->inter->string, tab->type->string, t->string,
nil, &err);
runtime·panic(err);
}
copyout(t, &i.data, ret);
}
#pragma textflag NOSPLIT
func assertI2T2(t *Type, i Iface) (ret byte, ...) {
bool *ok;
int32 wid;
wid = t->size;
ok = (bool*)(&ret + wid);
if(i.tab == nil || i.tab->type != t) {
*ok = false;
runtime·memclr(&ret, wid);
return;
}
*ok = true;
copyout(t, &i.data, &ret);
}
func assertI2TOK(t *Type, i Iface) (ok bool) {
ok = i.tab!=nil && i.tab->type==t;
}
static void assertE2Tret(Type *t, Eface e, byte *ret);
/*
* NOTE: Cannot use 'func' here. See assertI2T above.
*/
#pragma textflag NOSPLIT
void
runtime·assertE2T(Type *t, Eface e, GoOutput retbase)
{
assertE2Tret(t, e, (byte*)&retbase);
}
static void
assertE2Tret(Type *t, Eface e, byte *ret)
{
Eface err;
if(e.type == nil) {
runtime·newTypeAssertionError(
nil, nil, t->string,
nil, &err);
runtime·panic(err);
}
if(e.type != t) {
runtime·newTypeAssertionError(
nil, e.type->string, t->string,
nil, &err);
runtime·panic(err);
}
copyout(t, &e.data, ret);
}
#pragma textflag NOSPLIT
func assertE2T2(t *Type, e Eface) (ret byte, ...) {
bool *ok;
int32 wid;
wid = t->size;
ok = (bool*)(&ret + wid);
if(t != e.type) {
*ok = false;
runtime·memclr(&ret, wid);
return;
}
*ok = true;
copyout(t, &e.data, &ret);
}
func assertE2TOK(t *Type, e Eface) (ok bool) {
ok = t==e.type;
}
func convI2E(i Iface) (ret Eface) {
Itab *tab;
ret.data = i.data;
if((tab = i.tab) == nil)
ret.type = nil;
else
ret.type = tab->type;
}
func assertI2E(inter *InterfaceType, i Iface) (ret Eface) {
Itab *tab;
Eface err;
tab = i.tab;
if(tab == nil) {
// explicit conversions require non-nil interface value.
runtime·newTypeAssertionError(
nil, nil, inter->string,
nil, &err);
runtime·panic(err);
}
ret.data = i.data;
ret.type = tab->type;
}
func assertI2E2(inter *InterfaceType, i Iface) (ret Eface, ok bool) {
Itab *tab;
USED(inter);
tab = i.tab;
if(tab == nil) {
ret.type = nil;
ok = 0;
} else {
ret.type = tab->type;
ok = 1;
}
ret.data = i.data;
}
func convI2I(inter *InterfaceType, i Iface) (ret Iface) {
Itab *tab;
ret.data = i.data;
if((tab = i.tab) == nil)
ret.tab = nil;
else if(tab->inter == inter)
ret.tab = tab;
else
ret.tab = itab(inter, tab->type, 0);
}
void
runtime·ifaceI2I(InterfaceType *inter, Iface i, Iface *ret)
{
Itab *tab;
Eface err;
tab = i.tab;
if(tab == nil) {
// explicit conversions require non-nil interface value.
runtime·newTypeAssertionError(
nil, nil, inter->string,
nil, &err);
runtime·panic(err);
}
ret->data = i.data;
ret->tab = itab(inter, tab->type, 0);
}
func assertI2I(inter *InterfaceType, i Iface) (ret Iface) {
runtime·ifaceI2I(inter, i, &ret);
}
func assertI2I2(inter *InterfaceType, i Iface) (ret Iface, ok bool) {
Itab *tab;
tab = i.tab;
if(tab != nil && (tab->inter == inter || (tab = itab(inter, tab->type, 1)) != nil)) {
ret.data = i.data;
ret.tab = tab;
ok = 1;
} else {
ret.data = 0;
ret.tab = 0;
ok = 0;
}
}
void
runtime·ifaceE2I(InterfaceType *inter, Eface e, Iface *ret)
{
Type *t;
Eface err;
t = e.type;
if(t == nil) {
// explicit conversions require non-nil interface value.
runtime·newTypeAssertionError(
nil, nil, inter->string,
nil, &err);
runtime·panic(err);
}
ret->data = e.data;
ret->tab = itab(inter, t, 0);
}
bool
runtime·ifaceE2I2(InterfaceType *inter, Eface e, Iface *ret)
{
ret->tab = itab(inter, e.type, 1);
if(ret->tab == nil)
return false;
ret->data = e.data;
return true;
}
func reflect·ifaceE2I(inter *InterfaceType, e Eface, dst *Iface) {
runtime·ifaceE2I(inter, e, dst);
}
func assertE2I(inter *InterfaceType, e Eface) (ret Iface) {
runtime·ifaceE2I(inter, e, &ret);
}
func assertE2I2(inter *InterfaceType, e Eface) (ret Iface, ok bool) {
if(e.type == nil) {
ok = 0;
ret.data = nil;
ret.tab = nil;
} else if((ret.tab = itab(inter, e.type, 1)) == nil) {
ok = 0;
ret.data = nil;
} else {
ok = 1;
ret.data = e.data;
}
}
func assertE2E(inter *InterfaceType, e Eface) (ret Eface) {
Type *t;
Eface err;
t = e.type;
if(t == nil) {
// explicit conversions require non-nil interface value.
runtime·newTypeAssertionError(
nil, nil, inter->string,
nil, &err);
runtime·panic(err);
}
ret = e;
}
func assertE2E2(inter *InterfaceType, e Eface) (ret Eface, ok bool) {
USED(inter);
ret = e;
ok = e.type != nil;
}
static uintptr
ifacehash1(void *data, Type *t, uintptr h)
{
Alg *alg;
uintptr size;
Eface err;
if(t == nil)
return 0;
alg = t->alg;
size = t->size;
if(alg->hash == runtime·nohash) {
// calling nohash will panic too,
// but we can print a better error.
runtime·newErrorString(runtime·catstring(runtime·gostringnocopy((byte*)"hash of unhashable type "), *t->string), &err);
runtime·panic(err);
}
if(size <= sizeof(data))
alg->hash(&h, size, &data);
else
alg->hash(&h, size, data);
return h;
}
uintptr
runtime·ifacehash(Iface a, uintptr h)
{
if(a.tab == nil)
return h;
return ifacehash1(a.data, a.tab->type, h);
}
uintptr
runtime·efacehash(Eface a, uintptr h)
{
return ifacehash1(a.data, a.type, h);
}
static bool
ifaceeq1(void *data1, void *data2, Type *t)
{
uintptr size;
Alg *alg;
Eface err;
bool eq;
alg = t->alg;
size = t->size;
if(alg->equal == runtime·noequal) {
// calling noequal will panic too,
// but we can print a better error.
runtime·newErrorString(runtime·catstring(runtime·gostringnocopy((byte*)"comparing uncomparable type "), *t->string), &err);
runtime·panic(err);
}
eq = 0;
if(size <= sizeof(data1))
alg->equal(&eq, size, &data1, &data2);
else
alg->equal(&eq, size, data1, data2);
return eq;
}
bool
runtime·ifaceeq_c(Iface i1, Iface i2)
{
if(i1.tab != i2.tab)
return false;
if(i1.tab == nil)
return true;
return ifaceeq1(i1.data, i2.data, i1.tab->type);
}
bool
runtime·efaceeq_c(Eface e1, Eface e2)
{
if(e1.type != e2.type)
return false;
if(e1.type == nil)
return true;
return ifaceeq1(e1.data, e2.data, e1.type);
}
func ifaceeq(i1 Iface, i2 Iface) (ret bool) {
ret = runtime·ifaceeq_c(i1, i2);
}
func efaceeq(e1 Eface, e2 Eface) (ret bool) {
ret = runtime·efaceeq_c(e1, e2);
}
func ifacethash(i1 Iface) (ret uint32) {
Itab *tab;
ret = 0;
tab = i1.tab;
if(tab != nil)
ret = tab->type->hash;
}
func efacethash(e1 Eface) (ret uint32) {
Type *t;
ret = 0;
t = e1.type;
if(t != nil)
ret = t->hash;
}
func reflect·unsafe_Typeof(e Eface) (ret Eface) {
if(e.type == nil) {
ret.type = nil;
ret.data = nil;
} else {
ret = *(Eface*)(e.type);
}
}
func reflect·unsafe_New(t *Type) (ret *byte) {
ret = runtime·cnew(t);
}
func reflect·unsafe_NewArray(t *Type, n int) (ret *byte) {
ret = runtime·cnewarray(t, n);
}
func reflect·typelinks() (ret Slice) {
extern Type *typelink[], *etypelink[];
static int32 first = 1;
ret.array = (byte*)typelink;
ret.len = etypelink - typelink;
ret.cap = ret.len;
}