runtime: remove scase.releasetime field
This is the gofrontend version of https://golang.org/cl/245122.
Original CL description:
selectgo will report at most one block event, so there's no need to
keep a releasetime for every select case. It suffices to simply track
the releasetime of the case responsible for the wakeup.
Updates golang/go#40410.
This is being brought over to gofrontend as a step toward upgrading to
Go1.16beta1.
Change-Id: I60688303cdae72f89cfa9777402933ecee2503f7
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/279732
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
diff --git a/go/types.cc b/go/types.cc
index ecb93b0..12e7830 100644
--- a/go/types.cc
+++ b/go/types.cc
@@ -8908,11 +8908,10 @@
Type* uint16_type = Type::lookup_integer_type("uint16");
Type* int64_type = Type::lookup_integer_type("int64");
scase_type =
- Type::make_builtin_struct_type(4,
+ Type::make_builtin_struct_type(3,
"c", unsafe_pointer_type,
"elem", unsafe_pointer_type,
- "kind", uint16_type,
- "releasetime", int64_type);
+ "kind", uint16_type);
scase_type->set_is_struct_incomparable();
}
return scase_type;
diff --git a/libgo/go/runtime/select.go b/libgo/go/runtime/select.go
index c8910b8..81e00ec 100644
--- a/libgo/go/runtime/select.go
+++ b/libgo/go/runtime/select.go
@@ -32,10 +32,9 @@
// Known to compiler.
// Changes here must also be made in src/cmd/internal/gc/select.go's scasetype.
type scase struct {
- c *hchan // chan
- elem unsafe.Pointer // data element
- kind uint16
- releasetime int64
+ c *hchan // chan
+ elem unsafe.Pointer // data element
+ kind uint16
}
func sellock(scases []scase, lockorder []uint16) {
@@ -151,9 +150,6 @@
var t0 int64
if blockprofilerate > 0 {
t0 = cputicks()
- for i := 0; i < ncases; i++ {
- scases[i].releasetime = -1
- }
}
// The compiler rewrites selects that statically have
@@ -241,6 +237,7 @@
var dfl *scase
var casi int
var cas *scase
+ var caseReleaseTime int64 = -1
var recvOK bool
for i := 0; i < ncases; i++ {
casi = int(pollorder[i])
@@ -361,13 +358,13 @@
if k.kind == caseNil {
continue
}
- if sglist.releasetime > 0 {
- k.releasetime = sglist.releasetime
- }
if sg == sglist {
// sg has already been dequeued by the G that woke us up.
casi = int(casei)
cas = k
+ if sglist.releasetime > 0 {
+ caseReleaseTime = sglist.releasetime
+ }
} else {
c = k.c
if k.kind == caseSend {
@@ -465,8 +462,8 @@
goto retc
retc:
- if cas.releasetime > 0 {
- blockevent(cas.releasetime-t0, 1)
+ if caseReleaseTime > 0 {
+ blockevent(caseReleaseTime-t0, 1)
}
// Check preemption, since unlike gc we don't check on every call.