Merge 76acbabc39 into 49cdf0c42e

Fixes #74199

Change-Id: I6a15fbd59a3a3f8c496440f56d09d695e1504e4e
Reviewed-on: https://go-review.googlesource.com/c/go/+/682576
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Damien Neil <dneil@google.com>

src/crypto/cipher/gcm.go

@@ -82,7 +82,7 @@ func newGCM(cipher Block, nonceSize, tagSize int) (AEAD, error) {
 
 // NewGCMWithRandomNonce returns the given cipher wrapped in Galois Counter
 // Mode, with randomly-generated nonces. The cipher must have been created by
-// [aes.NewCipher].
+// [crypto/aes.NewCipher].
 //
 // It generates a random 96-bit nonce, which is prepended to the ciphertext by Seal,
 // and is extracted from the ciphertext by Open. The NonceSize of the AEAD is zero,

src/encoding/base64/base64.go

@@ -16,6 +16,7 @@ import (
  * Encodings
  */
 
+ type MappingFunc func (in uint) byte
 // An Encoding is a radix 64 encoding/decoding scheme, defined by a
 // 64-character alphabet. The most common encoding is the "base64"
 // encoding defined in RFC 4648 and used in MIME (RFC 2045) and PEM
@@ -26,6 +27,8 @@ type Encoding struct {
 	decodeMap [256]uint8 // mapping of symbol byte value to symbol index
 	padChar   rune
 	strict    bool
+	encodeMapFunc MappingFunc // optional mapping function to replace table look-ups when encoding
+	decodeMapFunc MappingFunc // optional mapping function to replace table look-ups when decoding
 }
 
 const (
@@ -83,6 +86,10 @@ func NewEncoding(encoder string) *Encoding {
 		}
 		e.decodeMap[encoder[i]] = uint8(i)
 	}
+	var encodeFunc = e.encodeMapDefault
+	e.encodeMapFunc = encodeFunc
+	var decodeFunc = e.decodeMapDefault
+	e.decodeMapFunc = decodeFunc
 	return e
 }
 
@@ -104,6 +111,17 @@ func (enc Encoding) WithPadding(padding rune) *Encoding {
 	return &enc
 }
 
+// WithDecodeMappingFunc sets the value fo encodeMapFunc
+func (enc Encoding) WithDecodeMappingFunc(f MappingFunc) *Encoding {
+	enc.decodeMapFunc = f
+	return &enc
+}
+// WithEncodeMappingFunc sets the value fo encodeMapFunc
+func (enc Encoding) WithEncodeMappingFunc(f MappingFunc) *Encoding {
+	enc.encodeMapFunc = f
+	return &enc
+}
+
 // Strict creates a new encoding identical to enc except with
 // strict decoding enabled. In this mode, the decoder requires that
 // trailing padding bits are zero, as described in RFC 4648 section 3.5.
@@ -116,11 +134,15 @@ func (enc Encoding) Strict() *Encoding {
 }
 
 // StdEncoding is the standard base64 encoding, as defined in RFC 4648.
-var StdEncoding = NewEncoding("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
+var StdEncoding = NewEncoding("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/").
+	WithEncodeMappingFunc(StandardBase64Encode).
+	WithDecodeMappingFunc(StandardBase64Decode)
 
 // URLEncoding is the alternate base64 encoding defined in RFC 4648.
 // It is typically used in URLs and file names.
-var URLEncoding = NewEncoding("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_")
+var URLEncoding = NewEncoding("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_").
+	WithEncodeMappingFunc(UrlSafeBase64Encode).
+	WithDecodeMappingFunc(UrlSafeBase64Decode)
 
 // RawStdEncoding is the standard raw, unpadded base64 encoding,
 // as defined in RFC 4648 section 3.2.
@@ -157,10 +179,10 @@ func (enc *Encoding) Encode(dst, src []byte) {
 		// Convert 3x 8bit source bytes into 4 bytes
 		val := uint(src[si+0])<<16 | uint(src[si+1])<<8 | uint(src[si+2])
 
-		dst[di+0] = enc.encode[val>>18&0x3F]
-		dst[di+1] = enc.encode[val>>12&0x3F]
-		dst[di+2] = enc.encode[val>>6&0x3F]
-		dst[di+3] = enc.encode[val&0x3F]
+		dst[di+0] = enc.encodeMapFunc(val>>18&0x3F)
+		dst[di+1] = enc.encodeMapFunc(val>>12&0x3F)
+		dst[di+2] = enc.encodeMapFunc(val>>6&0x3F)
+		dst[di+3] = enc.encodeMapFunc(val&0x3F)
 
 		si += 3
 		di += 4
@@ -176,8 +198,8 @@ func (enc *Encoding) Encode(dst, src []byte) {
 		val |= uint(src[si+1]) << 8
 	}
 
-	dst[di+0] = enc.encode[val>>18&0x3F]
-	dst[di+1] = enc.encode[val>>12&0x3F]
+	dst[di+0] = enc.encodeMapFunc(val>>18&0x3F)
+	dst[di+1] = enc.encodeMapFunc(val>>12&0x3F)
 
 	switch remain {
 	case 2:
@@ -330,8 +352,7 @@ func (enc *Encoding) decodeQuantum(dst, src []byte, si int) (nsi, n int, err err
 		}
 		in := src[si]
 		si++
-
-		out := enc.decodeMap[in]
+		out := enc.decodeMapFunc(uint(in))
 		if out != 0xff {
 			dbuf[j] = out
 			continue
@@ -529,14 +550,14 @@ func (enc *Encoding) Decode(dst, src []byte) (n int, err error) {
 	for strconv.IntSize >= 64 && len(src)-si >= 8 && len(dst)-n >= 8 {
 		src2 := src[si : si+8]
 		if dn, ok := assemble64(
-			enc.decodeMap[src2[0]],
-			enc.decodeMap[src2[1]],
-			enc.decodeMap[src2[2]],
-			enc.decodeMap[src2[3]],
-			enc.decodeMap[src2[4]],
-			enc.decodeMap[src2[5]],
-			enc.decodeMap[src2[6]],
-			enc.decodeMap[src2[7]],
+			enc.decodeMapFunc(uint(src2[0])),
+			enc.decodeMapFunc(uint(src2[1])),
+			enc.decodeMapFunc(uint(src2[2])),
+			enc.decodeMapFunc(uint(src2[3])),
+			enc.decodeMapFunc(uint(src2[4])),
+			enc.decodeMapFunc(uint(src2[5])),
+			enc.decodeMapFunc(uint(src2[6])),
+			enc.decodeMapFunc(uint(src2[7])),
 		); ok {
 			byteorder.BEPutUint64(dst[n:], dn)
 			n += 6
@@ -554,10 +575,10 @@ func (enc *Encoding) Decode(dst, src []byte) (n int, err error) {
 	for len(src)-si >= 4 && len(dst)-n >= 4 {
 		src2 := src[si : si+4]
 		if dn, ok := assemble32(
-			enc.decodeMap[src2[0]],
-			enc.decodeMap[src2[1]],
-			enc.decodeMap[src2[2]],
-			enc.decodeMap[src2[3]],
+			enc.decodeMapFunc(uint(src2[0])),
+			enc.decodeMapFunc(uint(src2[1])),
+			enc.decodeMapFunc(uint(src2[2])),
+			enc.decodeMapFunc(uint(src2[3])),
 		); ok {
 			byteorder.BEPutUint32(dst[n:], dn)
 			n += 3

src/encoding/base64/mapping.go

@@ -0,0 +1,94 @@
+// Copyright 2025 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 base64 implements base64 encoding as specified by RFC 4648.
+package base64
+
+func (enc Encoding) encodeMapDefault(in uint) byte {
+	return enc.encode[in]
+}
+
+func (enc Encoding) decodeMapDefault(in uint) byte {
+	return enc.decodeMap[in]
+}
+
+func StandardBase64Decode(in uint) byte {
+	ch := int(in)
+	ret := -1
+
+	// if (ch > 0x40 && ch < 0x5b) ret += ch - 0x41 + 1; // -64
+	ret += (((0x40 - ch) & (ch - 0x5b)) >> 8) & (ch - 64)
+
+	// if (ch > 0x60 && ch < 0x7b) ret += ch - 0x61 + 26 + 1; // -70
+	ret += (((0x60 - ch) & (ch - 0x7b)) >> 8) & (ch - 70)
+
+	// if (ch > 0x2f && ch < 0x3a) ret += ch - 0x30 + 52 + 1; // 5
+	ret += (((0x2f - ch) & (ch - 0x3a)) >> 8) & (ch + 5)
+
+	// if (ch == 0x2b) ret += 62 + 1
+	ret += (((0x2a - ch) & (ch - 0x2c)) >> 8) & 63
+
+	// if (ch == 0x2f) ret += 63 + 1;
+	ret += (((0x2e - ch) & (ch - 0x30)) >> 8) & 64
+
+	return byte(ret)
+}
+
+func StandardBase64Encode(in uint) byte {
+	src := int(in)
+	diff := int(0x41)
+
+	// if (in > 25) diff += 0x61 - 0x41 - 26; // 6
+	diff += ((25 - src) >> 8) & 6;
+
+	// if (in > 51) diff += 0x30 - 0x61 - 26; // -75
+	diff -= ((51 - src) >> 8) & 75;
+
+	// if (in > 61) diff += 0x2b - 0x30 - 10; // -15
+	diff -= ((61 - src) >> 8) & 15;
+
+	// if (in > 62) diff += 0x2f - 0x2b - 1; // 3
+	diff += ((62 - src) >> 8) & 3
+	return byte(src + diff)
+}
+
+func UrlSafeBase64Decode(in uint) byte {
+	ch := int(in)
+	ret := -1
+
+	// if (ch > 0x40 && ch < 0x5b) ret += ch - 0x41 + 1; // -64
+	ret += (((0x40 - ch) & (ch - 0x5b)) >> 8) & (ch - 64)
+
+	// if (ch > 0x60 && ch < 0x7b) ret += ch - 0x61 + 26 + 1; // -70
+	ret += (((0x60 - ch) & (ch - 0x7b)) >> 8) & (ch - 70)
+
+	// if (ch > 0x2f && ch < 0x3a) ret += ch - 0x30 + 52 + 1; // 5
+	ret += (((0x2f - ch) & (ch - 0x3a)) >> 8) & (ch + 5)
+
+	// if (ch == 0x2c) ret += 62 + 1;
+	ret += (((0x2c - ch) & (ch - 0x2e)) >> 8) & 63
+
+	// if (ch == 0x5f) ret += 63 + 1;
+	ret += (((0x5e - ch) & (ch - 0x60)) >> 8) & 64
+
+	return byte(ret)
+}
+
+
+func UrlSafeBase64Encode(in uint) byte {
+	src := int(in)
+	diff := int(0x41)
+	// if (src > 25) diff += 0x61 - 0x41 - 26; // 6
+	diff += ((25 - src) >> 8) & 6
+
+	// if (src > 51) diff += 0x30 - 0x61 - 26; // -75
+	diff -= ((51 - src) >> 8) & 75
+
+	// if (src > 61) diff += 0x2d - 0x30 - 10; // -13
+	diff -= ((61 - src) >> 8) & 13
+
+	// if (src > 62) diff += 0x5f - 0x2b - 1; // 3
+	diff += ((62 - src) >> 8) & 49
+	return byte(src + diff)
+}

src/go/doc/testdata/issue62640.0.golden

@@ -0,0 +1,22 @@
+// 
+PACKAGE issue62640
+
+IMPORTPATH
+	testdata/issue62640
+
+FILENAMES
+	testdata/issue62640.go
+
+TYPES
+	// 
+	type E struct{}
+
+	// F should be hidden within S because of the S.F field. 
+	func (E) F()
+
+	// 
+	type S struct {
+		E
+		F	int
+	}
+

src/go/doc/testdata/issue62640.1.golden

@@ -0,0 +1,22 @@
+// 
+PACKAGE issue62640
+
+IMPORTPATH
+	testdata/issue62640
+
+FILENAMES
+	testdata/issue62640.go
+
+TYPES
+	// 
+	type E struct{}
+
+	// F should be hidden within S because of the S.F field. 
+	func (E) F()
+
+	// 
+	type S struct {
+		E
+		F	int
+	}
+

src/go/doc/testdata/issue62640.2.golden

@@ -0,0 +1,25 @@
+// 
+PACKAGE issue62640
+
+IMPORTPATH
+	testdata/issue62640
+
+FILENAMES
+	testdata/issue62640.go
+
+TYPES
+	// 
+	type E struct{}
+
+	// F should be hidden within S because of the S.F field. 
+	func (E) F()
+
+	// 
+	type S struct {
+		E
+		F	int
+	}
+
+	// F should be hidden within S because of the S.F field. 
+	func (S) F()
+

src/go/doc/testdata/issue62640.go

@@ -0,0 +1,15 @@
+// Copyright 2025 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 issue62640
+
+type E struct{}
+
+// F should be hidden within S because of the S.F field.
+func (E) F() {}
+
+type S struct {
+	E
+	F int
+}

src/runtime/mheap.go

@@ -312,8 +312,10 @@ type heapArena struct {
 	// during marking.
 	pageSpecials [pagesPerArena / 8]uint8
 
-	// pageUseSpanDartboard is a bitmap that indicates which spans are
-	// heap spans and also gcUsesSpanDartboard.
+	// pageUseSpanInlineMarkBits is a bitmap where each bit corresponds
+	// to a span, as only spans one page in size can have inline mark bits.
+	// The bit indicates that the span has a spanInlineMarkBits struct
+	// stored directly at the top end of the span's memory.
 	pageUseSpanInlineMarkBits [pagesPerArena / 8]uint8
 
 	// checkmarks stores the debug.gccheckmark state. It is only

src/testing/synctest/helper_test.go

@@ -0,0 +1,15 @@
+// Copyright 2025 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 synctest_test
+
+import "testing"
+
+// helperLog is a t.Helper which logs.
+// Since it is a helper, the log prefix should contain
+// the caller's file, not helper_test.go.
+func helperLog(t *testing.T, s string) {
+	t.Helper()
+	t.Log(s)
+}

src/testing/synctest/synctest_test.go

@@ -140,6 +140,18 @@ func TestRun(t *testing.T) {
 	})
 }
 
+func TestHelper(t *testing.T) {
+	runTest(t, []string{"-test.v"}, func() {
+		synctest.Test(t, func(t *testing.T) {
+			helperLog(t, "log in helper")
+		})
+	}, `^=== RUN   TestHelper
+    synctest_test.go:.* log in helper
+--- PASS: TestHelper.*
+PASS
+$`)
+}
+
 func wantPanic(t *testing.T, want string) {
 	if e := recover(); e != nil {
 		if got := fmt.Sprint(e); got != want {

src/testing/testing.go

@@ -1261,6 +1261,9 @@ func (c *common) Skipped() bool {
 // When printing file and line information, that function will be skipped.
 // Helper may be called simultaneously from multiple goroutines.
 func (c *common) Helper() {
+	if c.isSynctest {
+		c = c.parent
+	}
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	if c.helperPCs == nil {