gc: fix reflect table method receiver
Fixes #451.
Fixes #770.
R=ken2
CC=golang-dev
https://golang.org/cl/2207045
diff --git a/doc/go_spec.html b/doc/go_spec.html
index 8735d4e..ea7a75c 100644
--- a/doc/go_spec.html
+++ b/doc/go_spec.html
@@ -5168,6 +5168,6 @@
<h2 id="Implementation_differences"><span class="alert">Implementation differences - TODO</span></h2>
<ul>
<li><span class="alert">Implementation does not honor the restriction on goto statements and targets (no intervening declarations).</span></li>
- <li><span class="alert">Method expressions are partially implemented.</span></li>
+ <li><span class="alert">Gccgo: Method expressions are partially implemented.</span></li>
<li><span class="alert">Gccgo: allows only one init() function per source file.</span></li>
</ul>
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 06bc573..acbfde4 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -1010,7 +1010,7 @@
* reflect.c
*/
void dumptypestructs(void);
-Type* methodfunc(Type *f, int use_receiver);
+Type* methodfunc(Type *f, Type*);
Node* typename(Type *t);
Sym* typesym(Type *t);
diff --git a/src/cmd/gc/reflect.c b/src/cmd/gc/reflect.c
index 87b9b04..18b2a4f 100644
--- a/src/cmd/gc/reflect.c
+++ b/src/cmd/gc/reflect.c
@@ -100,16 +100,16 @@
* return function type, receiver as first argument (or not).
*/
Type*
-methodfunc(Type *f, int use_receiver)
+methodfunc(Type *f, Type *receiver)
{
NodeList *in, *out;
Node *d;
Type *t;
in = nil;
- if(use_receiver) {
+ if(receiver) {
d = nod(ODCLFIELD, N, N);
- d->type = getthisx(f)->type->type;
+ d->type = receiver;
in = list(in, d);
}
for(t=getinargx(f)->type; t; t=t->down) {
@@ -185,8 +185,8 @@
a->name = method->name;
a->isym = methodsym(method, it, 1);
a->tsym = methodsym(method, t, 0);
- a->type = methodfunc(f->type, 1);
- a->mtype = methodfunc(f->type, 0);
+ a->type = methodfunc(f->type, t);
+ a->mtype = methodfunc(f->type, nil);
if(!(a->isym->flags & SymSiggen)) {
a->isym->flags |= SymSiggen;
@@ -241,22 +241,27 @@
Sig *a, *all, *last;
int o;
Type *f;
+ Sym *method, *isym;
+ Prog *oldlist;
all = nil;
last = nil;
o = 0;
+ oldlist = nil;
for(f=t->type; f; f=f->down) {
if(f->etype != TFIELD)
fatal("imethods: not field");
if(f->type->etype != TFUNC || f->sym == nil)
continue;
+ method = f->sym;
a = mal(sizeof(*a));
- a->name = f->sym->name;
- if(!exportname(f->sym->name))
- a->pkg = f->sym->pkg;
+ a->name = method->name;
+ if(!exportname(method->name))
+ a->pkg = method->pkg;
a->mtype = f->type;
a->offset = 0;
- a->type = methodfunc(f->type, 0);
+ a->type = methodfunc(f->type, nil);
+
if(last && sigcmp(last, a) >= 0)
fatal("sigcmp vs sortinter %s %s", last->name, a->name);
if(last == nil)
@@ -264,7 +269,43 @@
else
last->link = a;
last = a;
+
+ // Compiler can only refer to wrappers for
+ // named interface types.
+ if(t->sym == S)
+ continue;
+
+ // NOTE(rsc): Perhaps an oversight that
+ // IfaceType.Method is not in the reflect data.
+ // Generate the method body, so that compiled
+ // code can refer to it.
+ isym = methodsym(method, t, 0);
+ if(!(isym->flags & SymSiggen)) {
+ isym->flags |= SymSiggen;
+ if(oldlist == nil)
+ oldlist = pc;
+ genwrapper(t, f, isym, 0);
+ }
+
+ // Generate wrapper for pointer to interface type.
+ isym = methodsym(method, ptrto(t), 0);
+ if(!(isym->flags & SymSiggen)) {
+ isym->flags |= SymSiggen;
+ if(oldlist == nil)
+ oldlist = pc;
+ genwrapper(ptrto(t), f, isym, 0);
+ }
}
+
+ if(oldlist) {
+ // old list ended with AEND; change to ANOP
+ // so that the trampolines that follow can be found.
+ nopout(oldlist);
+
+ // start new data list
+ newplist();
+ }
+
return all;
}
diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 1c736d4..821d540 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -17,6 +17,7 @@
static int onearg(Node*, char*, ...);
static int twoarg(Node*);
static int lookdot(Node*, Type*, int);
+static int looktypedot(Node*, Type*, int);
static void typecheckaste(int, int, Type*, NodeList*, char*);
static Type* lookdot1(Sym *s, Type *t, Type *f, int);
static int nokeys(NodeList*);
@@ -497,6 +498,28 @@
yyerror("rhs of . must be a name"); // impossible
goto error;
}
+ sym = n->right->sym;
+ if(l->op == OTYPE) {
+ if(!looktypedot(n, t, 0)) {
+ if(looktypedot(n, t, 1))
+ yyerror("%#N undefined (cannot refer to unexported method %S)", n, n->right->sym);
+ else
+ yyerror("%#N undefined (type %T has no method %S)", n, t, n->right->sym);
+ goto error;
+ }
+ if(n->type->etype != TFUNC || n->type->thistuple != 1) {
+ yyerror("type %T has no method %hS", n->left->type, sym);
+ n->type = T;
+ goto error;
+ }
+ n->op = ONAME;
+ n->sym = methodsym(sym, l->type, 0);
+ n->type = methodfunc(n->type, l->type);
+ n->xoffset = 0;
+ n->class = PFUNC;
+ ok = Erv;
+ goto ret;
+ }
if(isptr[t->etype]) {
t = t->type;
if(t == T)
@@ -504,34 +527,13 @@
n->op = ODOTPTR;
checkwidth(t);
}
- sym = n->right->sym;
if(!lookdot(n, t, 0)) {
if(lookdot(n, t, 1))
- yyerror("%#N undefined (cannot refer to unexported field %S)", n, n->right->sym);
+ yyerror("%#N undefined (cannot refer to unexported field or method %S)", n, n->right->sym);
else
- yyerror("%#N undefined (type %T has no field %S)", n, t, n->right->sym);
+ yyerror("%#N undefined (type %T has no field or method %S)", n, t, n->right->sym);
goto error;
}
- if(l->op == OTYPE) {
- if(n->type->etype != TFUNC || n->type->thistuple != 1) {
- yyerror("type %T has no method %hS", n->left->type, sym);
- n->type = T;
- goto error;
- }
- if(t->etype == TINTER) {
- yyerror("method expression on interface not implemented");
- n->type = T;
- goto error;
- }
- n->op = ONAME;
- n->sym = methodsym(sym, l->type, 0);
- n->type = methodfunc(n->type, 1);
- n->xoffset = 0;
- getinargx(n->type)->type->type = l->type; // fix up receiver
- n->class = PFUNC;
- ok = Erv;
- goto ret;
- }
switch(n->op) {
case ODOTINTER:
case ODOTMETH:
@@ -1382,6 +1384,55 @@
}
static int
+looktypedot(Node *n, Type *t, int dostrcmp)
+{
+ Type *f1, *f2, *tt;
+ Sym *s;
+
+ s = n->right->sym;
+
+ if(t->etype == TINTER) {
+ f1 = lookdot1(s, t, t->type, dostrcmp);
+ if(f1 == T)
+ return 0;
+
+ if(f1->width == BADWIDTH)
+ fatal("lookdot badwidth %T %p", f1, f1);
+ n->right = methodname(n->right, t);
+ n->xoffset = f1->width;
+ n->type = f1->type;
+ n->op = ODOTINTER;
+ return 1;
+ }
+
+ tt = t;
+ if(t->sym == S && isptr[t->etype])
+ tt = t->type;
+
+ f2 = methtype(tt);
+ if(f2 == T)
+ return 0;
+
+ expandmeth(f2->sym, f2);
+ f2 = lookdot1(s, f2, f2->xmethod, dostrcmp);
+
+ // disallow T.m if m requires *T receiver
+ if(isptr[getthisx(f2->type)->type->type->etype]
+ && !isptr[t->etype]
+ && f2->embedded != 2
+ && !isifacemethod(f2->type)) {
+ yyerror("invalid method expression %#N (needs pointer receiver: (*%T).%s)", n, t, f2->sym->name);
+ return 0;
+ }
+
+ n->right = methodname(n->right, t);
+ n->xoffset = f2->width;
+ n->type = f2->type;
+ n->op = ODOTMETH;
+ return 1;
+}
+
+static int
lookdot(Node *n, Type *t, int dostrcmp)
{
Type *f1, *f2, *tt, *rcvr;
@@ -1394,9 +1445,15 @@
if(t->etype == TSTRUCT || t->etype == TINTER)
f1 = lookdot1(s, t, t->type, dostrcmp);
- f2 = methtype(n->left->type);
- if(f2 != T)
- f2 = lookdot1(s, f2, f2->method, dostrcmp);
+ f2 = T;
+ if(n->left->type == t || n->left->type->sym == S) {
+ f2 = methtype(t);
+ if(f2 != T) {
+ // Use f2->method, not f2->xmethod: adddot has
+ // already inserted all the necessary embedded dots.
+ f2 = lookdot1(s, f2, f2->method, dostrcmp);
+ }
+ }
if(f1 != T) {
if(f2 != T)
@@ -1420,7 +1477,7 @@
tt = n->left->type;
dowidth(tt);
rcvr = getthisx(f2->type)->type->type;
- if(n->left->op != OTYPE && !eqtype(rcvr, tt)) {
+ if(!eqtype(rcvr, tt)) {
if(rcvr->etype == tptr && eqtype(rcvr->type, tt)) {
checklvalue(n->left, "call pointer method on");
addrescapes(n->left);
diff --git a/src/pkg/reflect/all_test.go b/src/pkg/reflect/all_test.go
index 61d7f2c..39d43d1 100644
--- a/src/pkg/reflect/all_test.go
+++ b/src/pkg/reflect/all_test.go
@@ -1046,6 +1046,11 @@
t.Errorf("Type Method returned %d; want 250", i)
}
+ i = Typeof(&p).Method(0).Func.Call([]Value{NewValue(&p), NewValue(10)})[0].(*IntValue).Get()
+ if i != 250 {
+ t.Errorf("Pointer Type Method returned %d; want 250", i)
+ }
+
// Curried method of value.
i = NewValue(p).Method(0).Call([]Value{NewValue(10)})[0].(*IntValue).Get()
if i != 250 {
@@ -1288,9 +1293,12 @@
t.Error(s)
}
-type inner struct{}
+type inner struct {
+ x int
+}
type outer struct {
+ y int
inner
}
@@ -1307,3 +1315,42 @@
}
}
}
+
+type innerInt struct {
+ x int
+}
+
+type outerInt struct {
+ y int
+ innerInt
+}
+
+func (i *innerInt) m() int {
+ return i.x
+}
+
+func TestEmbeddedMethods(t *testing.T) {
+ typ := Typeof((*outerInt)(nil))
+ if typ.NumMethod() != 1 || typ.Method(0).Func.Get() != NewValue((*outerInt).m).(*FuncValue).Get() {
+ t.Errorf("Wrong method table for outerInt: (m=%p)", (*outerInt).m)
+ for i := 0; i < typ.NumMethod(); i++ {
+ m := typ.Method(i)
+ t.Errorf("\t%d: %s %#x\n", i, m.Name, m.Func.Get())
+ }
+ }
+
+ i := &innerInt{3}
+ if v := NewValue(i).Method(0).Call(nil)[0].(*IntValue).Get(); v != 3 {
+ t.Errorf("i.m() = %d, want 3", v)
+ }
+
+ o := &outerInt{1, innerInt{2}}
+ if v := NewValue(o).Method(0).Call(nil)[0].(*IntValue).Get(); v != 2 {
+ t.Errorf("i.m() = %d, want 2", v)
+ }
+
+ f := (*outerInt).m
+ if v := f(o); v != 2 {
+ t.Errorf("f(o) = %d, want 2", v)
+ }
+}
diff --git a/src/pkg/template/template.go b/src/pkg/template/template.go
index 0defe94..455b6cc 100644
--- a/src/pkg/template/template.go
+++ b/src/pkg/template/template.go
@@ -597,10 +597,7 @@
for i := 0; i < n; i++ {
m := typ.Method(i)
mtyp := m.Type
- // We must check receiver type because of a bug in the reflection type tables:
- // it should not be possible to find a method with the wrong receiver type but
- // this can happen due to value/pointer receiver mismatch.
- if m.Name == name && mtyp.NumIn() == 1 && mtyp.NumOut() == 1 && mtyp.In(0) == typ {
+ if m.Name == name && mtyp.NumIn() == 1 && mtyp.NumOut() == 1 {
return v.Method(i).Call(nil)[0]
}
}
diff --git a/test/method.go b/test/method.go
index c751c1f..b52d978 100644
--- a/test/method.go
+++ b/test/method.go
@@ -19,7 +19,7 @@
func (s *S1) val() int { return 2 }
func (i I) val() int { return 3 }
func (i *I1) val() int { return 4 }
-//func (t T) val() int { return 7 }
+func (t T) val() int { return 7 }
func (t *T1) val() int { return 8 }
type Val interface {
@@ -34,6 +34,8 @@
var i I
var pi *I1
var pt *T1
+ var t T
+ var v Val
if s.val() != 1 {
println("s.val:", s.val())
@@ -75,7 +77,10 @@
println("(*I1).val(pi):", (*I1).val(pi))
panic("fail")
}
- // if t.val() != 7 { prinln("t.val:", t.val()); panic("fail") }
+ if t.val() != 7 {
+ println("t.val:", t.val())
+ panic("fail")
+ }
if pt.val() != 8 {
println("pt.val:", pt.val())
panic("fail")
@@ -101,11 +106,27 @@
println("pi.val:", val(pi))
panic("fail")
}
- // if val(t) != 7 { println("t.val:", val(t)); panic("fail") }
+ if val(t) != 7 {
+ println("t.val:", val(t))
+ panic("fail")
+ }
if val(pt) != 8 {
println("pt.val:", val(pt))
panic("fail")
}
- // if Val.val(i) != 3 { println("Val.val(i):", Val.val(i)); panic("fail") }
+ if Val.val(i) != 3 {
+ println("Val.val(i):", Val.val(i))
+ panic("fail")
+ }
+ v = i
+ if Val.val(v) != 3 {
+ println("Val.val(v):", Val.val(v))
+ panic("fail")
+ }
+ pv := &v
+ if pv.val() != 3 {
+ println("pv.val():", pv.val())
+ panic("fail")
+ }
}
diff --git a/test/method2.go b/test/method2.go
index 3ee0ae1..cda6d9a 100644
--- a/test/method2.go
+++ b/test/method2.go
@@ -6,9 +6,17 @@
package main
-type T struct {a int}
+type T struct {
+ a int
+}
type P *T
type P1 *T
-func (p P) val() int { return 1 } // ERROR "receiver"
-func (p *P1) val() int { return 1 } // ERROR "receiver"
+func (p P) val() int { return 1 } // ERROR "receiver"
+func (p *P1) val() int { return 1 } // ERROR "receiver"
+
+type Val interface {
+ val() int
+}
+
+var _ = (*Val).val // ERROR "method"
