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fbab1f1bad
go/src/cmd/gc/dcl.c
Russ Cox 607eaea456 gc: fix smaller-than-pointer-sized receivers in interfaces 
Fixes #812.

R=ken2
CC=golang-dev
https://golang.org/cl/1904041
2010-07-26 15:25:10 -07:00

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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.
#include "go.h"
#include "y.tab.h"
static void funcargs(Node*);
static int
dflag(void)
{
if(!debug['d'])
return 0;
if(debug['y'])
return 1;
if(incannedimport)
return 0;
return 1;
}
/*
* declaration stack & operations
*/
static Sym* dclstack;
static void
dcopy(Sym *a, Sym *b)
{
a->pkg = b->pkg;
a->name = b->name;
a->def = b->def;
a->block = b->block;
a->lastlineno = b->lastlineno;
}
static Sym*
push(void)
{
Sym *d;
d = mal(sizeof(*d));
d->link = dclstack;
dclstack = d;
return d;
}
static Sym*
pushdcl(Sym *s)
{
Sym *d;
d = push();
dcopy(d, s);
if(dflag())
print("\t%L push %S %p\n", lineno, s, s->def);
return d;
}
void
popdcl(void)
{
Sym *d, *s;
// if(dflag())
// print("revert\n");
for(d=dclstack; d!=S; d=d->link) {
if(d->name == nil)
break;
s = pkglookup(d->name, d->pkg);
dcopy(s, d);
if(dflag())
print("\t%L pop %S %p\n", lineno, s, s->def);
}
if(d == S)
fatal("popdcl: no mark");
dclstack = d->link;
block = d->block;
}
void
poptodcl(void)
{
Sym *d, *s;
for(d=dclstack; d!=S; d=d->link) {
if(d->name == nil)
break;
s = pkglookup(d->name, d->pkg);
dcopy(s, d);
if(dflag())
print("\t%L pop %S\n", lineno, s);
}
if(d == S)
fatal("poptodcl: no mark");
dclstack = d;
}
void
markdcl(void)
{
Sym *d;
d = push();
d->name = nil; // used as a mark in fifo
d->block = block;
blockgen++;
block = blockgen;
// if(dflag())
// print("markdcl\n");
}
void
dumpdcl(char *st)
{
Sym *s, *d;
int i;
i = 0;
for(d=dclstack; d!=S; d=d->link) {
i++;
print(" %.2d %p", i, d);
if(d->name == nil) {
print("\n");
continue;
}
print(" '%s'", d->name);
s = pkglookup(d->name, d->pkg);
print(" %lS\n", s);
}
}
void
testdclstack(void)
{
Sym *d;
for(d=dclstack; d!=S; d=d->link) {
if(d->name == nil) {
yyerror("mark left on the stack");
continue;
}
}
}
void
redeclare(Sym *s, char *where)
{
if(s->lastlineno == 0)
yyerror("%S redeclared %s\n"
"\tprevious declaration during import",
s, where);
else
yyerror("%S redeclared %s\n"
"\tprevious declaration at %L",
s, where, s->lastlineno);
}
/*
* declare individual names - var, typ, const
*/
void
declare(Node *n, int ctxt)
{
Sym *s;
int gen;
static int typegen, vargen;
if(isblank(n))
return;
n->lineno = parserline();
s = n->sym;
gen = 0;
if(ctxt == PEXTERN) {
externdcl = list(externdcl, n);
if(dflag())
print("\t%L global decl %S %p\n", lineno, s, n);
} else {
if(curfn == nil && ctxt == PAUTO)
fatal("automatic outside function");
if(curfn != nil)
curfn->dcl = list(curfn->dcl, n);
if(n->op == OTYPE)
gen = ++typegen;
else if(n->op == ONAME)
gen = ++vargen;
pushdcl(s);
}
if(ctxt == PAUTO)
n->xoffset = BADWIDTH;
if(s->block == block)
redeclare(s, "in this block");
s->block = block;
s->lastlineno = parserline();
s->def = n;
n->vargen = gen;
n->funcdepth = funcdepth;
n->class = ctxt;
autoexport(n, ctxt);
}
void
addvar(Node *n, Type *t, int ctxt)
{
if(n==N || n->sym == S || (n->op != ONAME && n->op != ONONAME) || t == T)
fatal("addvar: n=%N t=%T nil", n, t);
n->op = ONAME;
declare(n, ctxt);
n->type = t;
}
/*
* declare variables from grammar
* new_name_list (type | [type] = expr_list)
*/
NodeList*
variter(NodeList *vl, Node *t, NodeList *el)
{
int doexpr;
Node *v, *e, *as2;
NodeList *init;
init = nil;
doexpr = el != nil;
if(count(el) == 1 && count(vl) > 1) {
e = el->n;
as2 = nod(OAS2, N, N);
as2->list = vl;
as2->rlist = list1(e);
for(; vl; vl=vl->next) {
v = vl->n;
v->op = ONAME;
declare(v, dclcontext);
v->ntype = t;
v->defn = as2;
if(funcdepth > 0)
init = list(init, nod(ODCL, v, N));
}
return list(init, as2);
}
for(; vl; vl=vl->next) {
if(doexpr) {
if(el == nil) {
yyerror("missing expr in var dcl");
break;
}
e = el->n;
el = el->next;
} else
e = N;
v = vl->n;
v->op = ONAME;
declare(v, dclcontext);
v->ntype = t;
if(e != N || funcdepth > 0 || isblank(v)) {
if(funcdepth > 0)
init = list(init, nod(ODCL, v, N));
e = nod(OAS, v, e);
init = list(init, e);
if(e->right != N)
v->defn = e;
}
}
if(el != nil)
yyerror("extra expr in var dcl");
return init;
}
/*
* declare constants from grammar
* new_name_list [[type] = expr_list]
*/
NodeList*
constiter(NodeList *vl, Node *t, NodeList *cl)
{
Node *v, *c;
NodeList *vv;
vv = nil;
if(cl == nil) {
if(t != N)
yyerror("constdcl cannot have type without expr");
cl = lastconst;
t = lasttype;
} else {
lastconst = cl;
lasttype = t;
}
cl = listtreecopy(cl);
for(; vl; vl=vl->next) {
if(cl == nil) {
yyerror("missing expr in const dcl");
break;
}
c = cl->n;
cl = cl->next;
v = vl->n;
v->op = OLITERAL;
declare(v, dclcontext);
v->ntype = t;
v->defn = c;
vv = list(vv, nod(ODCLCONST, v, N));
}
if(cl != nil)
yyerror("extra expr in const dcl");
iota += 1;
return vv;
}
/*
* this generates a new name node,
* typically for labels or other one-off names.
*/
Node*
newname(Sym *s)
{
Node *n;
if(s == S)
fatal("newname nil");
n = nod(ONAME, N, N);
n->sym = s;
n->type = T;
n->addable = 1;
n->ullman = 1;
n->xoffset = 0;
return n;
}
/*
* this generates a new name node for a name
* being declared.
*/
Node*
dclname(Sym *s)
{
Node *n;
n = newname(s);
n->op = ONONAME; // caller will correct it
return n;
}
Node*
typenod(Type *t)
{
// if we copied another type with *t = *u
// then t->nod might be out of date, so
// check t->nod->type too
if(t->nod == N || t->nod->type != t) {
t->nod = nod(OTYPE, N, N);
t->nod->type = t;
t->nod->sym = t->sym;
}
return t->nod;
}
/*
* this will return an old name
* that has already been pushed on the
* declaration list. a diagnostic is
* generated if no name has been defined.
*/
Node*
oldname(Sym *s)
{
Node *n;
Node *c;
n = s->def;
if(n == N) {
// maybe a top-level name will come along
// to give this a definition later.
// walkdef will check s->def again once
// all the input source has been processed.
n = newname(s);
n->op = ONONAME;
n->iota = iota; // save current iota value in const declarations
}
if(curfn != nil && n->funcdepth > 0 && n->funcdepth != funcdepth && n->op == ONAME) {
// inner func is referring to var in outer func.
//
// TODO(rsc): If there is an outer variable x and we
// are parsing x := 5 inside the closure, until we get to
// the := it looks like a reference to the outer x so we'll
// make x a closure variable unnecessarily.
if(n->closure == N || n->closure->funcdepth != funcdepth) {
// create new closure var.
c = nod(ONAME, N, N);
c->sym = s;
c->class = PPARAMREF;
c->isddd = n->isddd;
c->defn = n;
c->addable = 0;
c->ullman = 2;
c->funcdepth = funcdepth;
c->outer = n->closure;
n->closure = c;
c->closure = n;
c->xoffset = 0;
curfn->cvars = list(curfn->cvars, c);
}
// return ref to closure var, not original
return n->closure;
}
return n;
}
/*
* same for types
*/
Type*
newtype(Sym *s)
{
Type *t;
t = typ(TFORW);
t->sym = s;
t->type = T;
return t;
}
/*
* type check top level declarations
*/
void
dclchecks(void)
{
NodeList *l;
for(l=externdcl; l; l=l->next) {
if(l->n->op != ONAME)
continue;
typecheck(&l->n, Erv);
}
}
/*
* := declarations
*/
static int
colasname(Node *n)
{
switch(n->op) {
case ONAME:
case ONONAME:
case OPACK:
case OTYPE:
case OLITERAL:
return n->sym != S;
}
return 0;
}
void
colasdefn(NodeList *left, Node *defn)
{
int nnew;
NodeList *l;
Node *n;
nnew = 0;
for(l=left; l; l=l->next) {
n = l->n;
if(isblank(n))
continue;
if(!colasname(n)) {
yyerror("non-name %#N on left side of :=", n);
continue;
}
if(n->sym->block == block)
continue;
nnew++;
n = newname(n->sym);
declare(n, dclcontext);
n->defn = defn;
defn->ninit = list(defn->ninit, nod(ODCL, n, N));
l->n = n;
}
if(nnew == 0)
yyerror("no new variables on left side of :=");
}
Node*
colas(NodeList *left, NodeList *right)
{
Node *as;
as = nod(OAS2, N, N);
as->list = left;
as->rlist = right;
as->colas = 1;
colasdefn(left, as);
// make the tree prettier; not necessary
if(count(left) == 1 && count(right) == 1) {
as->left = as->list->n;
as->right = as->rlist->n;
as->list = nil;
as->rlist = nil;
as->op = OAS;
}
return as;
}
/*
* declare the function proper
* and declare the arguments.
* called in extern-declaration context
* returns in auto-declaration context.
*/
void
funchdr(Node *n)
{
if(n->nname != N) {
n->nname->op = ONAME;
declare(n->nname, PFUNC);
n->nname->defn = n;
}
// change the declaration context from extern to auto
if(funcdepth == 0 && dclcontext != PEXTERN)
fatal("funchdr: dclcontext");
dclcontext = PAUTO;
markdcl();
funcdepth++;
n->outer = curfn;
curfn = n;
if(n->nname)
funcargs(n->nname->ntype);
else
funcargs(n->ntype);
}
static void
funcargs(Node *nt)
{
Node *n;
NodeList *l;
if(nt->op != OTFUNC)
fatal("funcargs %O", nt->op);
// declare the receiver and in arguments.
// no n->defn because type checking of func header
// will fill in the types before we can demand them.
if(nt->left != N) {
n = nt->left;
if(n->op != ODCLFIELD)
fatal("funcargs1 %O", n->op);
if(n->left != N) {
n->left->op = ONAME;
n->left->ntype = n->right;
declare(n->left, PPARAM);
}
}
for(l=nt->list; l; l=l->next) {
n = l->n;
if(n->op != ODCLFIELD)
fatal("funcargs2 %O", n->op);
if(n->left != N) {
n->left->op = ONAME;
n->left->ntype = n->right;
declare(n->left, PPARAM);
}
}
// declare the out arguments.
for(l=nt->rlist; l; l=l->next) {
n = l->n;
if(n->op != ODCLFIELD)
fatal("funcargs3 %O", n->op);
if(n->left != N) {
n->left->op = ONAME;
n->left->ntype = n->right;
declare(n->left, PPARAMOUT);
}
}
}
/*
* finish the body.
* called in auto-declaration context.
* returns in extern-declaration context.
*/
void
funcbody(Node *n)
{
// change the declaration context from auto to extern
if(dclcontext != PAUTO)
fatal("funcbody: dclcontext");
popdcl();
funcdepth--;
curfn = n->outer;
n->outer = N;
if(funcdepth == 0)
dclcontext = PEXTERN;
}
/*
* new type being defined with name s.
*/
Node*
typedcl0(Sym *s)
{
Node *n;
n = dclname(s);
n->op = OTYPE;
declare(n, dclcontext);
return n;
}
/*
* node n, which was returned by typedcl0
* is being declared to have uncompiled type t.
* return the ODCLTYPE node to use.
*/
Node*
typedcl1(Node *n, Node *t, int local)
{
n->ntype = t;
n->local = local;
return nod(ODCLTYPE, n, N);
}
/*
* typedcl1 but during imports
*/
void
typedcl2(Type *pt, Type *t)
{
Node *n;
if(pt->etype == TFORW)
goto ok;
if(!eqtype(pt->orig, t))
yyerror("inconsistent definition for type %S during import\n\t%lT\n\t%lT", pt->sym, pt, t);
return;
ok:
n = pt->nod;
*pt = *t;
pt->method = nil;
pt->nod = n;
pt->sym = n->sym;
pt->sym->lastlineno = parserline();
declare(n, PEXTERN);
checkwidth(pt);
}
/*
* structs, functions, and methods.
* they don't belong here, but where do they belong?
*/
/*
* turn a parsed struct into a type
*/
static Type**
stotype(NodeList *l, int et, Type **t)
{
Type *f, *t1, *t2, **t0;
Strlit *note;
int lno;
NodeList *init;
Node *n;
char *what;
t0 = t;
init = nil;
lno = lineno;
what = "field";
if(et == TINTER)
what = "method";
for(; l; l=l->next) {
n = l->n;
lineno = n->lineno;
note = nil;
if(n->op != ODCLFIELD)
fatal("stotype: oops %N\n", n);
if(n->right != N) {
if(et == TINTER && n->left != N) {
// queue resolution of method type for later.
// right now all we need is the name list.
// avoids cycles for recursive interface types.
n->type = typ(TINTERMETH);
n->type->nname = n->right;
n->right = N;
n->left->type = n->type;
queuemethod(n);
} else {
typecheck(&n->right, Etype);
n->type = n->right->type;
if(n->type == T) {
*t0 = T;
return t0;
}
if(n->left != N)
n->left->type = n->type;
n->right = N;
if(n->embedded && n->type != T) {
t1 = n->type;
if(t1->sym == S && isptr[t1->etype])
t1 = t1->type;
if(isptr[t1->etype])
yyerror("embedded type cannot be a pointer");
else if(t1->etype == TFORW && t1->embedlineno == 0)
t1->embedlineno = lineno;
}
}
}
if(n->type == T) {
// assume error already printed
continue;
}
switch(n->val.ctype) {
case CTSTR:
if(et != TSTRUCT)
yyerror("interface method cannot have annotation");
note = n->val.u.sval;
break;
default:
if(et != TSTRUCT)
yyerror("interface method cannot have annotation");
else
yyerror("field annotation must be string");
case CTxxx:
note = nil;
break;
}
if(et == TINTER && n->left == N) {
// embedded interface - inline the methods
if(n->type->etype != TINTER) {
if(n->type->etype == TFORW)
yyerror("interface type loop involving %T", n->type);
else
yyerror("interface contains embedded non-interface %T", n->type);
continue;
}
for(t1=n->type->type; t1!=T; t1=t1->down) {
f = typ(TFIELD);
f->type = t1->type;
f->width = BADWIDTH;
f->nname = newname(t1->sym);
f->sym = t1->sym;
for(t2=*t0; t2!=T; t2=t2->down) {
if(t2->sym == f->sym) {
yyerror("duplicate method %s", t2->sym->name);
break;
}
}
*t = f;
t = &f->down;
}
continue;
}
f = typ(TFIELD);
f->type = n->type;
f->note = note;
f->width = BADWIDTH;
f->isddd = n->isddd;
if(n->left != N && n->left->op == ONAME) {
f->nname = n->left;
f->embedded = n->embedded;
f->sym = f->nname->sym;
if(importpkg && !exportname(f->sym->name))
f->sym = pkglookup(f->sym->name, structpkg);
if(f->sym && !isblank(f->nname)) {
for(t1=*t0; t1!=T; t1=t1->down) {
if(t1->sym == f->sym) {
yyerror("duplicate %s %s", what, t1->sym->name);
break;
}
}
}
}
*t = f;
t = &f->down;
}
*t = T;
lineno = lno;
return t;
}
Type*
dostruct(NodeList *l, int et)
{
Type *t;
int funarg;
/*
* convert a parsed id/type list into
* a type for struct/interface/arglist
*/
funarg = 0;
if(et == TFUNC) {
funarg = 1;
et = TSTRUCT;
}
t = typ(et);
t->funarg = funarg;
stotype(l, et, &t->type);
if(t->type == T && l != nil) {
t->broke = 1;
return t;
}
if(!funarg)
checkwidth(t);
return t;
}
Node*
embedded(Sym *s)
{
Node *n;
char *name;
// Names sometimes have disambiguation junk
// appended after a center dot. Discard it when
// making the name for the embedded struct field.
enum { CenterDot = 0xB7 };
name = s->name;
if(utfrune(s->name, CenterDot)) {
name = strdup(s->name);
*utfrune(name, CenterDot) = 0;
}
n = newname(lookup(name));
n = nod(ODCLFIELD, n, oldname(s));
n->embedded = 1;
return n;
}
/*
* check that the list of declarations is either all anonymous or all named
*/
static Node*
findtype(NodeList *l)
{
for(; l; l=l->next)
if(l->n->op == OKEY)
return l->n->right;
return N;
}
NodeList*
checkarglist(NodeList *all, int input)
{
int named;
Node *n, *t, *nextt;
NodeList *l;
named = 0;
for(l=all; l; l=l->next) {
if(l->n->op == OKEY) {
named = 1;
break;
}
}
if(named) {
n = N;
for(l=all; l; l=l->next) {
n = l->n;
if(n->op != OKEY && n->sym == S) {
yyerror("mixed named and unnamed function parameters");
break;
}
}
if(l == nil && n != N && n->op != OKEY)
yyerror("final function parameter must have type");
}
nextt = nil;
for(l=all; l; l=l->next) {
// can cache result from findtype to avoid
// quadratic behavior here, but unlikely to matter.
n = l->n;
if(named) {
if(n->op == OKEY) {
t = n->right;
n = n->left;
nextt = nil;
} else {
if(nextt == nil)
nextt = findtype(l);
t = nextt;
}
} else {
t = n;
n = N;
}
if(isblank(n))
n = N;
if(n != N && n->sym == S) {
t = n;
n = N;
}
if(n != N)
n = newname(n->sym);
n = nod(ODCLFIELD, n, t);
if(n->right != N && n->right->op == ODDD) {
if(!input)
yyerror("cannot use ... in output argument list");
else if(l->next != nil)
yyerror("can only use ... as final argument in list");
n->right->op = OTARRAY;
n->right->right = n->right->left;
n->right->left = N;
n->isddd = 1;
if(n->left != N)
n->left->isddd = 1;
}
l->n = n;
}
return all;
}
Node*
fakethis(void)
{
Node *n;
n = nod(ODCLFIELD, N, typenod(ptrto(typ(TSTRUCT))));
return n;
}
/*
* Is this field a method on an interface?
* Those methods have an anonymous
* *struct{} as the receiver.
* (See fakethis above.)
*/
int
isifacemethod(Type *f)
{
Type *rcvr;
Type *t;
rcvr = getthisx(f)->type;
if(rcvr->sym != S)
return 0;
t = rcvr->type;
if(!isptr[t->etype])
return 0;
t = t->type;
if(t->sym != S || t->etype != TSTRUCT || t->type != T)
return 0;
return 1;
}
/*
* turn a parsed function declaration
* into a type
*/
Type*
functype(Node *this, NodeList *in, NodeList *out)
{
Type *t;
NodeList *rcvr;
t = typ(TFUNC);
rcvr = nil;
if(this)
rcvr = list1(this);
t->type = dostruct(rcvr, TFUNC);
t->type->down = dostruct(out, TFUNC);
t->type->down->down = dostruct(in, TFUNC);
if(this)
t->thistuple = 1;
t->outtuple = count(out);
t->intuple = count(in);
t->outnamed = t->outtuple > 0 && out->n->left != N;
return t;
}
Sym*
methodsym(Sym *nsym, Type *t0, int iface)
{
Sym *s;
char *p;
Type *t;
char *suffix;
t = t0;
if(t == T)
goto bad;
s = t->sym;
if(s == S) {
if(!isptr[t->etype])
goto bad;
t = t->type;
if(t == T)
goto bad;
s = t->sym;
if(s == S)
goto bad;
}
// if t0 == *t and t0 has a sym,
// we want to see *t, not t0, in the method name.
if(t != t0 && t0->sym)
t0 = ptrto(t);
suffix = "";
if(iface) {
dowidth(t0);
if(t0->width < types[tptr]->width)
suffix = "·i";
}
p = smprint("%#hT·%s%s", t0, nsym->name, suffix);
s = pkglookup(p, s->pkg);
free(p);
return s;
bad:
yyerror("illegal receiver type: %T", t0);
return S;
}
Node*
methodname(Node *n, Type *t)
{
Sym *s;
s = methodsym(n->sym, t, 0);
if(s == S)
return n;
return newname(s);
}
Node*
methodname1(Node *n, Node *t)
{
char *star;
char *p;
star = "";
if(t->op == OIND) {
star = "*";
t = t->left;
}
if(t->sym == S || isblank(n))
return newname(n->sym);
p = smprint("%s%S·%S", star, t->sym, n->sym);
n = newname(pkglookup(p, t->sym->pkg));
free(p);
return n;
}
/*
* add a method, declared as a function,
* n is fieldname, pa is base type, t is function type
*/
void
addmethod(Sym *sf, Type *t, int local)
{
Type *f, *d, *pa;
Node *n;
pa = nil;
// get field sym
if(sf == S)
fatal("no method symbol");
// get parent type sym
pa = getthisx(t)->type; // ptr to this structure
if(pa == T) {
yyerror("missing receiver");
return;
}
pa = pa->type;
f = methtype(pa);
if(f == T) {
yyerror("invalid receiver type %T", pa);
return;
}
pa = f;
if(importpkg && !exportname(sf->name))
sf = pkglookup(sf->name, importpkg);
n = nod(ODCLFIELD, newname(sf), N);
n->type = t;
d = T; // last found
for(f=pa->method; f!=T; f=f->down) {
d = f;
if(f->etype != TFIELD)
fatal("addmethod: not TFIELD: %N", f);
if(strcmp(sf->name, f->sym->name) != 0)
continue;
if(!eqtype(t, f->type))
yyerror("method redeclared: %T.%S\n\t%T\n\t%T", pa, sf, f->type, t);
return;
}
if(local && !pa->local) {
// defining method on non-local type.
yyerror("cannot define new methods on non-local type %T", pa);
return;
}
if(d == T)
stotype(list1(n), 0, &pa->method);
else
stotype(list1(n), 0, &d->down);
return;
}
void
funccompile(Node *n, int isclosure)
{
stksize = BADWIDTH;
maxarg = 0;
if(n->type == T) {
if(nerrors == 0)
fatal("funccompile missing type");
return;
}
// assign parameter offsets
checkwidth(n->type);
// record offset to actual frame pointer.
// for closure, have to skip over leading pointers and PC slot.
nodfp->xoffset = 0;
if(isclosure) {
NodeList *l;
for(l=n->nname->ntype->list; l; l=l->next) {
nodfp->xoffset += widthptr;
if(l->n->left == N) // found slot for PC
break;
}
}
if(curfn)
fatal("funccompile %S inside %S", n->nname->sym, curfn->nname->sym);
curfn = n;
typechecklist(n->nbody, Etop);
curfn = nil;
stksize = 0;
dclcontext = PAUTO;
funcdepth = n->funcdepth + 1;
compile(n);
curfn = nil;
funcdepth = 0;
dclcontext = PEXTERN;
}
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