mirror of
https://github.com/golang/go
synced 2024-11-11 19:21:37 -07:00
cmd/gc: do not generate code for var _ = ... unless necessary
Fixes #2443. R=ken2 CC=golang-dev https://golang.org/cl/6997048
This commit is contained in:
parent
a4600126d9
commit
6592456feb
@ -1375,6 +1375,7 @@ void walkexprlistsafe(NodeList *l, NodeList **init);
|
||||
void walkstmt(Node **np);
|
||||
void walkstmtlist(NodeList *l);
|
||||
Node* conv(Node*, Type*);
|
||||
int candiscard(Node*);
|
||||
|
||||
/*
|
||||
* arch-specific ggen.c/gsubr.c/gobj.c/pgen.c
|
||||
|
@ -55,6 +55,10 @@ anyinit(NodeList *n)
|
||||
case ODCLTYPE:
|
||||
case OEMPTY:
|
||||
break;
|
||||
case OAS:
|
||||
if(isblank(l->n->left) && candiscard(l->n->right))
|
||||
break;
|
||||
// fall through
|
||||
default:
|
||||
return 1;
|
||||
}
|
||||
|
@ -108,6 +108,13 @@ init1(Node *n, NodeList **out)
|
||||
case OAS:
|
||||
if(n->defn->left != n)
|
||||
goto bad;
|
||||
if(isblank(n->defn->left) && candiscard(n->defn->right)) {
|
||||
n->defn->op = OEMPTY;
|
||||
n->defn->left = N;
|
||||
n->defn->right = N;
|
||||
break;
|
||||
}
|
||||
|
||||
/*
|
||||
n->defn->dodata = 1;
|
||||
init1(n->defn->right, out);
|
||||
|
@ -183,8 +183,8 @@ walkstmt(Node **np)
|
||||
dump("nottop", n);
|
||||
break;
|
||||
|
||||
case OASOP:
|
||||
case OAS:
|
||||
case OASOP:
|
||||
case OAS2:
|
||||
case OAS2DOTTYPE:
|
||||
case OAS2RECV:
|
||||
@ -3226,3 +3226,112 @@ usefield(Node *n)
|
||||
curfn->paramfld = l;
|
||||
}
|
||||
|
||||
static int
|
||||
candiscardlist(NodeList *l)
|
||||
{
|
||||
for(; l; l=l->next)
|
||||
if(!candiscard(l->n))
|
||||
return 0;
|
||||
return 1;
|
||||
}
|
||||
|
||||
int
|
||||
candiscard(Node *n)
|
||||
{
|
||||
if(n == N)
|
||||
return 1;
|
||||
|
||||
switch(n->op) {
|
||||
default:
|
||||
return 0;
|
||||
|
||||
case ONAME:
|
||||
case ONONAME:
|
||||
case OTYPE:
|
||||
case OPACK:
|
||||
case OLITERAL:
|
||||
case OADD:
|
||||
case OSUB:
|
||||
case OOR:
|
||||
case OXOR:
|
||||
case OADDSTR:
|
||||
case OADDR:
|
||||
case OANDAND:
|
||||
case OARRAYBYTESTR:
|
||||
case OARRAYRUNESTR:
|
||||
case OSTRARRAYBYTE:
|
||||
case OSTRARRAYRUNE:
|
||||
case OCAP:
|
||||
case OCMPIFACE:
|
||||
case OCMPSTR:
|
||||
case OCOMPLIT:
|
||||
case OMAPLIT:
|
||||
case OSTRUCTLIT:
|
||||
case OARRAYLIT:
|
||||
case OPTRLIT:
|
||||
case OCONV:
|
||||
case OCONVIFACE:
|
||||
case OCONVNOP:
|
||||
case ODOT:
|
||||
case OEQ:
|
||||
case ONE:
|
||||
case OLT:
|
||||
case OLE:
|
||||
case OGT:
|
||||
case OGE:
|
||||
case OKEY:
|
||||
case OLEN:
|
||||
case OMUL:
|
||||
case OLSH:
|
||||
case ORSH:
|
||||
case OAND:
|
||||
case OANDNOT:
|
||||
case ONEW:
|
||||
case ONOT:
|
||||
case OCOM:
|
||||
case OPLUS:
|
||||
case OMINUS:
|
||||
case OOROR:
|
||||
case OPAREN:
|
||||
case ORUNESTR:
|
||||
case OREAL:
|
||||
case OIMAG:
|
||||
case OCOMPLEX:
|
||||
// Discardable as long as the subpieces are.
|
||||
break;
|
||||
|
||||
case ODIV:
|
||||
case OMOD:
|
||||
// Discardable as long as we know it's not division by zero.
|
||||
if(isconst(n->right, CTINT) && mpcmpfixc(n->right->val.u.xval, 0) != 0)
|
||||
break;
|
||||
if(isconst(n->right, CTFLT) && mpcmpfltc(n->right->val.u.fval, 0) != 0)
|
||||
break;
|
||||
return 0;
|
||||
|
||||
case OMAKECHAN:
|
||||
case OMAKEMAP:
|
||||
// Discardable as long as we know it won't fail because of a bad size.
|
||||
if(isconst(n->left, CTINT) && mpcmpfixc(n->left->val.u.xval, 0) == 0)
|
||||
break;
|
||||
return 0;
|
||||
|
||||
case OMAKESLICE:
|
||||
// Difficult to tell what sizes are okay.
|
||||
return 0;
|
||||
}
|
||||
|
||||
if(!candiscard(n->left) ||
|
||||
!candiscard(n->right) ||
|
||||
!candiscard(n->ntest) ||
|
||||
!candiscard(n->nincr) ||
|
||||
!candiscardlist(n->ninit) ||
|
||||
!candiscardlist(n->nbody) ||
|
||||
!candiscardlist(n->nelse) ||
|
||||
!candiscardlist(n->list) ||
|
||||
!candiscardlist(n->rlist)) {
|
||||
return 0;
|
||||
}
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
@ -16,13 +16,9 @@
|
||||
== fixedbugs/
|
||||
|
||||
=========== fixedbugs/bug429.go
|
||||
throw: all goroutines are asleep - deadlock!
|
||||
fatal error: all goroutines are asleep - deadlock!
|
||||
|
||||
== bugs/
|
||||
|
||||
=========== bugs/bug395.go
|
||||
bug395 is broken
|
||||
|
||||
=========== bugs/bug434.go
|
||||
bugs/bug434.dir/two.go:10: one.t.int undefined (cannot refer to unexported field or method one.int)
|
||||
BUG:bug434
|
||||
|
@ -259,3 +259,13 @@ var copy_pt0a = pt0a
|
||||
var copy_pt0b = pt0b
|
||||
var copy_pt1 = pt1
|
||||
var copy_pt1a = pt1a
|
||||
|
||||
var _ interface{} = 1
|
||||
|
||||
type T1 int
|
||||
|
||||
func (t *T1) M() {}
|
||||
|
||||
type Mer interface { M() }
|
||||
|
||||
var _ Mer = (*T1)(nil)
|
||||
|
Loading…
Reference in New Issue
Block a user