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stricter interface conversion rule: i.(T)

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must have non-nil i.

R=ken
OCL=29136
CL=29136
This commit is contained in:
Russ Cox 2009-05-20 18:23:19 -07:00
parent 140aed9ab7
commit 23e62d169f
4 changed files with 39 additions and 9 deletions
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1
src/cmd/gc/builtin.c.boot
View File

@ -32,6 +32,7 @@ char *sysimport =
"func sys.ifaceI2T (sigt *uint8, iface any) (ret any)\n"
"func sys.ifaceI2T2 (sigt *uint8, iface any) (ret any, ok bool)\n"
"func sys.ifaceI2I (sigi *uint8, iface any) (ret any)\n"
"func sys.ifaceI2Ix (sigi *uint8, iface any) (ret any)\n"
"func sys.ifaceI2I2 (sigi *uint8, iface any) (ret any, ok bool)\n"
"func sys.ifaceeq (i1 any, i2 any) (ret bool)\n"
"func sys.efaceeq (i1 any, i2 any) (ret bool)\n"

1
src/cmd/gc/sys.go
View File

@ -42,6 +42,7 @@ func ifaceT2I(sigi *byte, sigt *byte, elem any) (ret any);
func ifaceI2T(sigt *byte, iface any) (ret any);
func ifaceI2T2(sigt *byte, iface any) (ret any, ok bool);
func ifaceI2I(sigi *byte, iface any) (ret any);
func ifaceI2Ix(sigi *byte, iface any) (ret any);
func ifaceI2I2(sigi *byte, iface any) (ret any, ok bool);
func ifaceeq(i1 any, i2 any) (ret bool);
func efaceeq(i1 any, i2 any) (ret bool);

7
src/cmd/gc/walk.c
View File

@ -12,6 +12,7 @@ enum
I2T,
I2T2,
I2I,
I2Ix,
I2I2,
T2I,
I2Isame,
@ -524,7 +525,7 @@ loop:
case I2T:
et = I2T2;
break;
case I2I:
case I2Ix:
et = I2I2;
break;
case E2I:
@ -2947,6 +2948,8 @@ ifaceas1(Type *dst, Type *src, int explicit)
ifacecheck(dst, src, lineno, explicit);
if(isnilinter(src))
return E2I;
if(explicit)
return I2Ix;
return I2I;
}
if(isnilinter(dst))
@ -2983,6 +2986,7 @@ ifacename[] =
[I2T] = "ifaceI2T",
[I2T2] = "ifaceI2T2",
[I2I] = "ifaceI2I",
[I2Ix] = "ifaceI2Ix",
[I2I2] = "ifaceI2I2",
[I2Isame] = "ifaceI2Isame",
[E2T] = "ifaceE2T",
@ -3038,6 +3042,7 @@ ifacecvt(Type *tl, Node *n, int et)
case I2T:
case I2T2:
case I2I:
case I2Ix:
case I2I2:
case E2T:
case E2T2:

39
src/runtime/iface.c
View File

@ -431,6 +431,7 @@ sys·ifaceI2E(Iface i, Eface ret)
}
// ifaceI2I(sigi *byte, iface any) (ret any);
// called only for implicit (no type assertion) conversions
void
sys·ifaceI2I(Sigi *si, Iface i, Iface ret)
{
@ -438,7 +439,6 @@ sys·ifaceI2I(Sigi *si, Iface i, Iface ret)
im = i.type;
if(im == nil) {
//TODO(rsc): fixme
// If incoming interface is uninitialized (zeroed)
// make the outgoing interface zeroed as well.
ret = niliface;
@ -451,6 +451,27 @@ sys·ifaceI2I(Sigi *si, Iface i, Iface ret)
FLUSH(&ret);
}
// ifaceI2Ix(sigi *byte, iface any) (ret any);
// called only for explicit conversions (with type assertion).
void
sys·ifaceI2Ix(Sigi *si, Iface i, Iface ret)
{
Itype *im;
im = i.type;
if(im == nil) {
// explicit conversions require non-nil interface value.
printf("interface is nil, not %s\n", si->name);
throw("interface conversion");
} else {
ret = i;
if(im->sigi != si)
ret.type = itype(si, im->sigt, 0);
}
FLUSH(&ret);
}
// ifaceI2I2(sigi *byte, iface any) (ret any, ok bool);
void
sys·ifaceI2I2(Sigi *si, Iface i, Iface ret, bool ok)
@ -458,14 +479,13 @@ sys·ifaceI2I2(Sigi *si, Iface i, Iface ret, bool ok)
Itype *im;
im = i.type;
ok = true;
if(im == nil) {
//TODO: fixme
// If incoming interface is uninitialized (zeroed)
// make the outgoing interface zeroed as well.
// If incoming interface is nil, the conversion fails.
ret = niliface;
ok = false;
} else {
ret = i;
ok = true;
if(im->sigi != si) {
ret.type = itype(si, im->sigt, 1);
if(ret.type == nil) {
@ -480,6 +500,7 @@ sys·ifaceI2I2(Sigi *si, Iface i, Iface ret, bool ok)
}
// ifaceE2I(sigi *byte, iface any) (ret any);
// Called only for explicit conversions (with type assertion).
void
sys·ifaceE2I(Sigi *si, Eface e, Iface ret)
{
@ -487,8 +508,9 @@ sys·ifaceE2I(Sigi *si, Eface e, Iface ret)
t = e.type;
if(t == nil) {
//TODO(rsc): fixme
ret = niliface;
// explicit conversions require non-nil interface value.
printf("interface is nil, not %s\n", si->name);
throw("interface conversion");
} else {
ret.data = e.data;
ret.type = itype(si, t, 0);
@ -505,8 +527,9 @@ sys·ifaceE2I2(Sigi *si, Eface e, Iface ret, bool ok)
t = e.type;
ok = true;
if(t == nil) {
//TODO(rsc): fixme
// If incoming interface is nil, the conversion fails.
ret = niliface;
ok = false;
} else {
ret.data = e.data;
ret.type = itype(si, t, 1);