crypto/internal/boring: factor Cache into crypto/internal/boring/bcache

Requested by the maintainers of the OpenSSL-based fork of Go+BoringCrypto,
to make maintaining that fork easier.

Change-Id: I770e70ecc12b589034da31edecf59c73b2c6e1dd
Reviewed-on: https://go-review.googlesource.com/c/go/+/407135
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Russ Cox <rsc@golang.org>

src/crypto/ecdsa/boring.go

@@ -9,6 +9,7 @@ package ecdsa
 import (
 	"crypto/internal/boring"
 	"crypto/internal/boring/bbig"
+	"crypto/internal/boring/bcache"
 	"math/big"
 	"unsafe"
 )
@@ -26,8 +27,8 @@ import (
 // still matches before using the cached key. The theory is that the real
 // operations are significantly more expensive than the comparison.
 
-var pubCache boring.Cache
-var privCache boring.Cache
+var pubCache bcache.Cache
+var privCache bcache.Cache
 
 func init() {
 	pubCache.Register()

src/crypto/internal/boring/bcache/cache.go

@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package boring
+// Package bcache implements a GC-friendly cache (see [Cache]) for BoringCrypto.
+package bcache
 
 import (
 	"sync/atomic"

src/crypto/internal/boring/bcache/cache_test.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package boring
+package bcache
 
 import (
 	"fmt"

src/crypto/rsa/boring.go

@@ -9,6 +9,7 @@ package rsa
 import (
 	"crypto/internal/boring"
 	"crypto/internal/boring/bbig"
+	"crypto/internal/boring/bcache"
 	"math/big"
 	"unsafe"
 )
@@ -31,8 +32,8 @@ type boringPub struct {
 	orig PublicKey
 }
 
-var pubCache boring.Cache
-var privCache boring.Cache
+var pubCache bcache.Cache
+var privCache bcache.Cache
 
 func init() {
 	pubCache.Register()

src/go/build/deps_test.go

@@ -393,7 +393,7 @@ var depsRules = `
 	< net/mail;
 
 	NONE < crypto/internal/boring/sig, crypto/internal/boring/syso;
-	sync/atomic < crypto/internal/boring/fipstls;
+	sync/atomic < crypto/internal/boring/bcache, crypto/internal/boring/fipstls;
 	crypto/internal/boring/sig, crypto/internal/boring/fipstls < crypto/tls/fipsonly;
 
 	# CRYPTO is core crypto algorithms - no cgo, fmt, net.
@@ -410,7 +410,10 @@ var depsRules = `
 	< crypto/internal/nistec
 	< crypto/internal/edwards25519/field, golang.org/x/crypto/curve25519/internal/field
 	< crypto/internal/edwards25519
-	< crypto/cipher
+	< crypto/cipher;
+
+	crypto/cipher,
+	crypto/internal/boring/bcache
 	< crypto/internal/boring
 	< crypto/boring
 	< crypto/aes, crypto/des, crypto/hmac, crypto/md5, crypto/rc4,

src/runtime/mgc.go

@@ -1579,7 +1579,7 @@ func sync_runtime_registerPoolCleanup(f func()) {
 	poolcleanup = f
 }
 
-//go:linkname boring_registerCache crypto/internal/boring.registerCache
+//go:linkname boring_registerCache crypto/internal/boring/bcache.registerCache
 func boring_registerCache(p unsafe.Pointer) {
 	boringCaches = append(boringCaches, p)
 }