qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-19 22:04:44 -07:00
Code Releases Activity

cmd/gc, runtime: avoid unnecessary copy on type assertion.

Browse Source 
When the first result of a type assertion is blank, the compiler would still copy out a potentially large non-interface type.

Fixes #1021.

R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6812079
This commit is contained in:
Daniel Morsing 2012-11-06 20:40:40 +01:00
parent 433b2f17ee
commit d098bffd84
4 changed files with 43 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/cmd/gc/builtin.c
View File

@ -54,6 +54,8 @@ char *runtimeimport =
"func @\"\".assertI2I2(@\"\".typ *byte, @\"\".iface any) (@\"\".ret any, @\"\".ok bool)\n"
"func @\"\".assertI2T(@\"\".typ *byte, @\"\".iface any) (@\"\".ret any)\n"
"func @\"\".assertI2T2(@\"\".typ *byte, @\"\".iface any) (@\"\".ret any, @\"\".ok bool)\n"
"func @\"\".assertI2TOK(@\"\".typ *byte, @\"\".iface any) (@\"\".ok bool)\n"
"func @\"\".assertE2TOK(@\"\".typ *byte, @\"\".iface any) (@\"\".ok bool)\n"
"func @\"\".ifaceeq(@\"\".i1 any, @\"\".i2 any) (@\"\".ret bool)\n"
"func @\"\".efaceeq(@\"\".i1 any, @\"\".i2 any) (@\"\".ret bool)\n"
"func @\"\".ifacethash(@\"\".i1 any) (@\"\".ret uint32)\n"

2
src/cmd/gc/runtime.go
View File

@ -76,6 +76,8 @@ func assertI2I(typ *byte, iface any) (ret any)
func assertI2I2(typ *byte, iface any) (ret any, ok bool)
func assertI2T(typ *byte, iface any) (ret any)
func assertI2T2(typ *byte, iface any) (ret any, ok bool)
func assertI2TOK(typ *byte, iface any) (ok bool)
func assertE2TOK(typ *byte, iface any) (ok bool)
func ifaceeq(i1 any, i2 any) (ret bool)
func efaceeq(i1 any, i2 any) (ret bool)

25
src/cmd/gc/walk.c
View File

@ -686,6 +686,31 @@ walkexpr(Node **np, NodeList **init)
n->ninit = nil;
r = n->rlist->n;
walkexprlistsafe(n->list, init);
if(isblank(n->list->n) && !isinter(r->type)) {
strcpy(buf, "assert");
p = buf+strlen(buf);
if(isnilinter(r->left->type))
*p++ = 'E';
else
*p++ = 'I';
*p++ = '2';
*p++ = 'T';
*p++ = 'O';
*p++ = 'K';
*p = '\0';
fn = syslook(buf, 1);
ll = list1(typename(r->type));
ll = list(ll, r->left);
argtype(fn, r->left->type);
n1 = nod(OCALL, fn, N);
n1->list = ll;
n = nod(OAS, n->list->next->n, n1);
typecheck(&n, Etop);
walkexpr(&n, init);
goto ret;
}
r->op = ODOTTYPE2;
walkexpr(&r, init);
ll = ascompatet(n->op, n->list, &r->type, 0, init);

14
src/pkg/runtime/iface.c
View File

@ -278,6 +278,13 @@ runtime·assertI2T2(Type *t, Iface i, ...)
copyout(t, &i.data, ret);
}
void
runtime·assertI2TOK(Type *t, Iface i, bool ok)
{
ok = i.tab!=nil && i.tab->type==t;
FLUSH(&ok);
}
static void assertE2Tret(Type *t, Eface e, byte *ret);
// func ifaceE2T(typ *byte, iface any) (ret any)
@ -334,6 +341,13 @@ runtime·assertE2T2(Type *t, Eface e, ...)
copyout(t, &e.data, ret);
}
void
runtime·assertE2TOK(Type *t, Eface e, bool ok)
{
ok = t==e.type;
FLUSH(&ok);
}
// func convI2E(elem any) (ret any)
void
runtime·convI2E(Iface i, Eface ret)