From a1c3e24b5466ede5dd2d817cadc6d91d1ae56f18 Mon Sep 17 00:00:00 2001
From: Kir Kolyshkin <kolyshkin@gmail.com>
Date: Wed, 4 Sep 2024 18:19:44 -0700
Subject: [PATCH] cmd/internal/objabi: use sync.OnceValue

Change-Id: I09c134fff728d32c5bc475889b8c673cc18120a0
Reviewed-on: https://go-review.googlesource.com/c/go/+/611041
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
---
 src/cmd/internal/objabi/pkgspecial.go | 63 +++++++++++++--------------
 1 file changed, 30 insertions(+), 33 deletions(-)

diff --git a/src/cmd/internal/objabi/pkgspecial.go b/src/cmd/internal/objabi/pkgspecial.go
index f288096a02..0cf2e64e80 100644
--- a/src/cmd/internal/objabi/pkgspecial.go
+++ b/src/cmd/internal/objabi/pkgspecial.go
@@ -91,39 +91,36 @@ var allowAsmABIPkgs = []string{
 	"runtime/internal/startlinetest",
 }
 
-var (
-	pkgSpecials     map[string]PkgSpecial
-	pkgSpecialsOnce sync.Once
-)
-
 // LookupPkgSpecial returns special build properties for the given package path.
 func LookupPkgSpecial(pkgPath string) PkgSpecial {
-	pkgSpecialsOnce.Do(func() {
-		// Construct pkgSpecials from various package lists. This lets us use
-		// more flexible logic, while keeping the final map simple, and avoids
-		// the init-time cost of a map.
-		pkgSpecials = make(map[string]PkgSpecial)
-		set := func(elt string, f func(*PkgSpecial)) {
-			s := pkgSpecials[elt]
-			f(&s)
-			pkgSpecials[elt] = s
-		}
-		for _, pkg := range runtimePkgs {
-			set(pkg, func(ps *PkgSpecial) { ps.Runtime = true; ps.NoInstrument = true })
-		}
-		for _, pkg := range extraNoInstrumentPkgs {
-			if pkg[0] == '-' {
-				set(pkg[1:], func(ps *PkgSpecial) { ps.NoInstrument = false })
-			} else {
-				set(pkg, func(ps *PkgSpecial) { ps.NoInstrument = true })
-			}
-		}
-		for _, pkg := range noRaceFuncPkgs {
-			set(pkg, func(ps *PkgSpecial) { ps.NoRaceFunc = true })
-		}
-		for _, pkg := range allowAsmABIPkgs {
-			set(pkg, func(ps *PkgSpecial) { ps.AllowAsmABI = true })
-		}
-	})
-	return pkgSpecials[pkgPath]
+	return pkgSpecialsOnce()[pkgPath]
 }
+
+var pkgSpecialsOnce = sync.OnceValue(func() map[string]PkgSpecial {
+	// Construct pkgSpecials from various package lists. This lets us use
+	// more flexible logic, while keeping the final map simple, and avoids
+	// the init-time cost of a map.
+	pkgSpecials := make(map[string]PkgSpecial)
+	set := func(elt string, f func(*PkgSpecial)) {
+		s := pkgSpecials[elt]
+		f(&s)
+		pkgSpecials[elt] = s
+	}
+	for _, pkg := range runtimePkgs {
+		set(pkg, func(ps *PkgSpecial) { ps.Runtime = true; ps.NoInstrument = true })
+	}
+	for _, pkg := range extraNoInstrumentPkgs {
+		if pkg[0] == '-' {
+			set(pkg[1:], func(ps *PkgSpecial) { ps.NoInstrument = false })
+		} else {
+			set(pkg, func(ps *PkgSpecial) { ps.NoInstrument = true })
+		}
+	}
+	for _, pkg := range noRaceFuncPkgs {
+		set(pkg, func(ps *PkgSpecial) { ps.NoRaceFunc = true })
+	}
+	for _, pkg := range allowAsmABIPkgs {
+		set(pkg, func(ps *PkgSpecial) { ps.AllowAsmABI = true })
+	}
+	return pkgSpecials
+})
-- 
2.48.1