gcc/libgo/go/runtime/proflabel.go
Ian Lance Taylor a01dda3c23 compiler, libgo: change mangling scheme
Overhaul the mangling scheme to avoid ambiguities if the package path
contains a dot. Instead of using dot both to separate components and
to mangle characters, use dot only to separate components and use
underscore to mangle characters.

For golang/go#41862

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/271726
2020-11-20 12:44:35 -08:00

41 lines
1.5 KiB
Go

// Copyright 2017 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.
package runtime
import "unsafe"
var labelSync uintptr
//go:linkname runtime_setProfLabel runtime_1pprof.runtime__setProfLabel
func runtime_setProfLabel(labels unsafe.Pointer) {
// Introduce race edge for read-back via profile.
// This would more properly use &getg().labels as the sync address,
// but we do the read in a signal handler and can't call the race runtime then.
//
// This uses racereleasemerge rather than just racerelease so
// the acquire in profBuf.read synchronizes with *all* prior
// setProfLabel operations, not just the most recent one. This
// is important because profBuf.read will observe different
// labels set by different setProfLabel operations on
// different goroutines, so it needs to synchronize with all
// of them (this wouldn't be an issue if we could synchronize
// on &getg().labels since we would synchronize with each
// most-recent labels write separately.)
//
// racereleasemerge is like a full read-modify-write on
// labelSync, rather than just a store-release, so it carries
// a dependency on the previous racereleasemerge, which
// ultimately carries forward to the acquire in profBuf.read.
if raceenabled {
racereleasemerge(unsafe.Pointer(&labelSync))
}
getg().labels = labels
}
//go:linkname runtime_getProfLabel runtime_1pprof.runtime__getProfLabel
func runtime_getProfLabel() unsafe.Pointer {
return getg().labels
}