From 2b1fe999351ce7b10be9310a38d894bb2c0c7411 Mon Sep 17 00:00:00 2001 From: Keith Randall Date: Thu, 18 Jul 2019 16:02:37 -0400 Subject: [PATCH] bytes/hash: add hashing package for bytes and strings Fixes #28322 R=go1.14 RELNOTE=yes Change-Id: Ic29f8b587c8c77472260836a5c3e13edaded13fa Reviewed-on: https://go-review.googlesource.com/c/go/+/186877 Reviewed-by: Alan Donovan --- src/bytes/hash/hash.go | 185 +++++++++++++ src/bytes/hash/hash_test.go | 66 +++++ src/bytes/hash/smhasher_test.go | 461 ++++++++++++++++++++++++++++++++ src/go/build/deps_test.go | 102 +++---- 4 files changed, 764 insertions(+), 50 deletions(-) create mode 100644 src/bytes/hash/hash.go create mode 100644 src/bytes/hash/hash_test.go create mode 100644 src/bytes/hash/smhasher_test.go diff --git a/src/bytes/hash/hash.go b/src/bytes/hash/hash.go new file mode 100644 index 00000000000000..0e44e37ae7368e --- /dev/null +++ b/src/bytes/hash/hash.go @@ -0,0 +1,185 @@ +// Copyright 2019 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 bytes/hash provides hash functions on byte sequences. These +// hash functions are intended to be used to implement hash tables or +// other data structures that need to map arbitrary strings or byte +// sequences to a uniform distribution of integers. The hash functions +// are collision-resistant but are not cryptographically secure (use +// one of the hash functions in crypto/* if you need that). +// +// The produced hashes depend only on the sequence of bytes provided +// to the Hash object, not on the way in which they are provided. For +// example, the calls +// h.AddString("foo") +// h.AddBytes([]byte{'f','o','o'}) +// h.AddByte('f'); h.AddByte('o'); h.AddByte('o') +// will all have the same effect. +// +// Two Hash instances in the same process using the same seed +// behave identically. +// +// Two Hash instances with the same seed in different processes are +// not guaranteed to behave identically, even if the processes share +// the same binary. +// +// Hashes are intended to be collision-resistant, even for situations +// where an adversary controls the byte sequences being hashed. +// All bits of the Hash result are close to uniformly and +// independently distributed, so can be safely restricted to a range +// using bit masking, shifting, or modular arithmetic. +package hash + +import ( + "unsafe" +) + +// A Seed controls the behavior of a Hash. Two Hash objects with the +// same seed in the same process will behave identically. Two Hash +// objects with different seeds will very likely behave differently. +type Seed struct { + s uint64 +} + +// A Hash object is used to compute the hash of a byte sequence. +type Hash struct { + seed Seed // initial seed used for this hash + state Seed // current hash of all flushed bytes + buf [64]byte // unflushed byte buffer + n int // number of unflushed bytes +} + +// AddByte adds b to the sequence of bytes hashed by h. +func (h *Hash) AddByte(b byte) { + if h.n == len(h.buf) { + h.flush() + } + h.buf[h.n] = b + h.n++ +} + +// AddBytes adds b to the sequence of bytes hashed by h. +func (h *Hash) AddBytes(b []byte) { + for h.n+len(b) > len(h.buf) { + k := copy(h.buf[h.n:], b) + h.n = len(h.buf) + b = b[k:] + h.flush() + } + h.n += copy(h.buf[h.n:], b) +} + +// AddString adds the bytes of s to the sequence of bytes hashed by h. +func (h *Hash) AddString(s string) { + for h.n+len(s) > len(h.buf) { + k := copy(h.buf[h.n:], s) + h.n = len(h.buf) + s = s[k:] + h.flush() + } + h.n += copy(h.buf[h.n:], s) +} + +// Seed returns the seed value specified in the most recent call to +// SetSeed, or the initial seed if SetSeed was never called. +func (h *Hash) Seed() Seed { + return h.seed +} + +// SetSeed sets the seed used by h. Two Hash objects with the same +// seed in the same process will behave identically. Two Hash objects +// with different seeds will very likely behave differently. Any +// bytes added to h previous to this call will be discarded. +func (h *Hash) SetSeed(seed Seed) { + h.seed = seed + h.state = seed + h.n = 0 +} + +// Reset discards all bytes added to h. +// (The seed remains the same.) +func (h *Hash) Reset() { + h.state = h.seed + h.n = 0 +} + +// precondition: buffer is full. +func (h *Hash) flush() { + if h.n != len(h.buf) { + panic("flush of partially full buffer") + } + h.state.s = rthash(h.buf[:], h.state.s) + h.n = 0 +} + +// Hash returns a value which depends on h's seed and the sequence of +// bytes added to h (since the last call to Reset or SetSeed). +func (h *Hash) Hash() uint64 { + return rthash(h.buf[:h.n], h.state.s) +} + +// MakeSeed returns a Seed initialized using the bits in s. +// Two seeds generated with the same s are guaranteed to be equal. +// Two seeds generated with different s are very likely to be different. +// TODO: disallow this? See Alan's comment in the issue. +func MakeSeed(s uint64) Seed { + return Seed{s: s} +} + +// New returns a new Hash object. Different hash objects allocated by +// this function will very likely have different seeds. +func New() *Hash { + seed := Seed{s: uint64(runtime_fastrand())} + return &Hash{ + seed: seed, + state: seed, + } +} + +//go:linkname runtime_fastrand runtime.fastrand +func runtime_fastrand() uint32 + +func rthash(b []byte, seed uint64) uint64 { + if len(b) == 0 { + return seed + } + // The runtime hasher only works on uintptr. For 64-bit + // architectures, we use the hasher directly. Otherwise, + // we use two parallel hashers on the lower and upper 32 bits. + if unsafe.Sizeof(uintptr(0)) == 8 { + return uint64(runtime_memhash(unsafe.Pointer(&b[0]), uintptr(seed), uintptr(len(b)))) + } + lo := runtime_memhash(unsafe.Pointer(&b[0]), uintptr(seed), uintptr(len(b))) + hi := runtime_memhash(unsafe.Pointer(&b[0]), uintptr(seed>>32), uintptr(len(b))) + // TODO: mix lo/hi? Get 64 bits some other way? + return uint64(hi)<<32 | uint64(lo) +} + +//go:linkname runtime_memhash runtime.memhash +func runtime_memhash(p unsafe.Pointer, seed, s uintptr) uintptr + +// Wrapper functions so that a bytes/hash.Hash implements +// the hash.Hash and hash.Hash64 interfaces. + +func (h *Hash) Write(b []byte) (int, error) { + h.AddBytes(b) + return len(b), nil +} +func (h *Hash) Sum(b []byte) []byte { + x := h.Hash() + return append(b, + byte(x>>0), + byte(x>>8), + byte(x>>16), + byte(x>>24), + byte(x>>32), + byte(x>>40), + byte(x>>48), + byte(x>>56)) +} +func (h *Hash) Sum64() uint64 { + return h.Hash() +} +func (h *Hash) Size() int { return 8 } +func (h *Hash) BlockSize() int { return len(h.buf) } diff --git a/src/bytes/hash/hash_test.go b/src/bytes/hash/hash_test.go new file mode 100644 index 00000000000000..311f451be2e02f --- /dev/null +++ b/src/bytes/hash/hash_test.go @@ -0,0 +1,66 @@ +// Copyright 2019 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 hash_test + +import ( + "bytes/hash" + basehash "hash" + "testing" +) + +func TestUnseededHash(t *testing.T) { + m := map[uint64]struct{}{} + for i := 0; i < 1000; i++ { + h := hash.New() + m[h.Hash()] = struct{}{} + } + if len(m) < 900 { + t.Errorf("empty hash not sufficiently random: got %d, want 1000", len(m)) + } +} + +func TestSeededHash(t *testing.T) { + s := hash.MakeSeed(1234) + m := map[uint64]struct{}{} + for i := 0; i < 1000; i++ { + h := hash.New() + h.SetSeed(s) + m[h.Hash()] = struct{}{} + } + if len(m) != 1 { + t.Errorf("seeded hash is random: got %d, want 1", len(m)) + } +} + +func TestHashGrouping(t *testing.T) { + b := []byte("foo") + h1 := hash.New() + h2 := hash.New() + h2.SetSeed(h1.Seed()) + h1.AddBytes(b) + for _, x := range b { + h2.AddByte(x) + } + if h1.Hash() != h2.Hash() { + t.Errorf("hash of \"foo\" and \"f\",\"o\",\"o\" not identical") + } +} + +func TestHashBytesVsString(t *testing.T) { + s := "foo" + b := []byte(s) + h1 := hash.New() + h2 := hash.New() + h2.SetSeed(h1.Seed()) + h1.AddString(s) + h2.AddBytes(b) + if h1.Hash() != h2.Hash() { + t.Errorf("hash of string and byts not identical") + } +} + +// Make sure a Hash implements the hash.Hash and hash.Hash64 interfaces. +var _ basehash.Hash = &hash.Hash{} +var _ basehash.Hash64 = &hash.Hash{} diff --git a/src/bytes/hash/smhasher_test.go b/src/bytes/hash/smhasher_test.go new file mode 100644 index 00000000000000..1b7b44db09ddd0 --- /dev/null +++ b/src/bytes/hash/smhasher_test.go @@ -0,0 +1,461 @@ +// Copyright 2019 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 hash_test + +import ( + "bytes/hash" + "fmt" + "math" + "math/rand" + "runtime" + "strings" + "testing" +) + +// Smhasher is a torture test for hash functions. +// https://code.google.com/p/smhasher/ +// This code is a port of some of the Smhasher tests to Go. + +// Sanity checks. +// hash should not depend on values outside key. +// hash should not depend on alignment. +func TestSmhasherSanity(t *testing.T) { + r := rand.New(rand.NewSource(1234)) + const REP = 10 + const KEYMAX = 128 + const PAD = 16 + const OFFMAX = 16 + for k := 0; k < REP; k++ { + for n := 0; n < KEYMAX; n++ { + for i := 0; i < OFFMAX; i++ { + var b [KEYMAX + OFFMAX + 2*PAD]byte + var c [KEYMAX + OFFMAX + 2*PAD]byte + randBytes(r, b[:]) + randBytes(r, c[:]) + copy(c[PAD+i:PAD+i+n], b[PAD:PAD+n]) + if bytesHash(b[PAD:PAD+n], 0) != bytesHash(c[PAD+i:PAD+i+n], 0) { + t.Errorf("hash depends on bytes outside key") + } + } + } + } +} + +func bytesHash(b []byte, seed uint64) uint64 { + h := hash.New() + h.SetSeed(hash.MakeSeed(seed)) + h.AddBytes(b) + return h.Hash() +} +func stringHash(s string, seed uint64) uint64 { + h := hash.New() + h.SetSeed(hash.MakeSeed(seed)) + h.AddString(s) + return h.Hash() +} + +const hashSize = 64 + +func randBytes(r *rand.Rand, b []byte) { + r.Read(b) // can't fail +} + +// A hashSet measures the frequency of hash collisions. +type hashSet struct { + m map[uint64]struct{} // set of hashes added + n int // number of hashes added +} + +func newHashSet() *hashSet { + return &hashSet{make(map[uint64]struct{}), 0} +} +func (s *hashSet) add(h uint64) { + s.m[h] = struct{}{} + s.n++ +} +func (s *hashSet) addS(x string) { + s.add(stringHash(x, 0)) +} +func (s *hashSet) addB(x []byte) { + s.add(bytesHash(x, 0)) +} +func (s *hashSet) addS_seed(x string, seed uint64) { + s.add(stringHash(x, seed)) +} +func (s *hashSet) check(t *testing.T) { + const SLOP = 10.0 + collisions := s.n - len(s.m) + pairs := int64(s.n) * int64(s.n-1) / 2 + expected := float64(pairs) / math.Pow(2.0, float64(hashSize)) + stddev := math.Sqrt(expected) + if float64(collisions) > expected+SLOP*(3*stddev+1) { + t.Errorf("unexpected number of collisions: got=%d mean=%f stddev=%f", collisions, expected, stddev) + } +} + +// a string plus adding zeros must make distinct hashes +func TestSmhasherAppendedZeros(t *testing.T) { + s := "hello" + strings.Repeat("\x00", 256) + h := newHashSet() + for i := 0; i <= len(s); i++ { + h.addS(s[:i]) + } + h.check(t) +} + +// All 0-3 byte strings have distinct hashes. +func TestSmhasherSmallKeys(t *testing.T) { + h := newHashSet() + var b [3]byte + for i := 0; i < 256; i++ { + b[0] = byte(i) + h.addB(b[:1]) + for j := 0; j < 256; j++ { + b[1] = byte(j) + h.addB(b[:2]) + if !testing.Short() { + for k := 0; k < 256; k++ { + b[2] = byte(k) + h.addB(b[:3]) + } + } + } + } + h.check(t) +} + +// Different length strings of all zeros have distinct hashes. +func TestSmhasherZeros(t *testing.T) { + N := 256 * 1024 + if testing.Short() { + N = 1024 + } + h := newHashSet() + b := make([]byte, N) + for i := 0; i <= N; i++ { + h.addB(b[:i]) + } + h.check(t) +} + +// Strings with up to two nonzero bytes all have distinct hashes. +func TestSmhasherTwoNonzero(t *testing.T) { + if runtime.GOARCH == "wasm" { + t.Skip("Too slow on wasm") + } + if testing.Short() { + t.Skip("Skipping in short mode") + } + h := newHashSet() + for n := 2; n <= 16; n++ { + twoNonZero(h, n) + } + h.check(t) +} +func twoNonZero(h *hashSet, n int) { + b := make([]byte, n) + + // all zero + h.addB(b) + + // one non-zero byte + for i := 0; i < n; i++ { + for x := 1; x < 256; x++ { + b[i] = byte(x) + h.addB(b) + b[i] = 0 + } + } + + // two non-zero bytes + for i := 0; i < n; i++ { + for x := 1; x < 256; x++ { + b[i] = byte(x) + for j := i + 1; j < n; j++ { + for y := 1; y < 256; y++ { + b[j] = byte(y) + h.addB(b) + b[j] = 0 + } + } + b[i] = 0 + } + } +} + +// Test strings with repeats, like "abcdabcdabcdabcd..." +func TestSmhasherCyclic(t *testing.T) { + if testing.Short() { + t.Skip("Skipping in short mode") + } + r := rand.New(rand.NewSource(1234)) + const REPEAT = 8 + const N = 1000000 + for n := 4; n <= 12; n++ { + h := newHashSet() + b := make([]byte, REPEAT*n) + for i := 0; i < N; i++ { + b[0] = byte(i * 79 % 97) + b[1] = byte(i * 43 % 137) + b[2] = byte(i * 151 % 197) + b[3] = byte(i * 199 % 251) + randBytes(r, b[4:n]) + for j := n; j < n*REPEAT; j++ { + b[j] = b[j-n] + } + h.addB(b) + } + h.check(t) + } +} + +// Test strings with only a few bits set +func TestSmhasherSparse(t *testing.T) { + if runtime.GOARCH == "wasm" { + t.Skip("Too slow on wasm") + } + if testing.Short() { + t.Skip("Skipping in short mode") + } + sparse(t, 32, 6) + sparse(t, 40, 6) + sparse(t, 48, 5) + sparse(t, 56, 5) + sparse(t, 64, 5) + sparse(t, 96, 4) + sparse(t, 256, 3) + sparse(t, 2048, 2) +} +func sparse(t *testing.T, n int, k int) { + b := make([]byte, n/8) + h := newHashSet() + setbits(h, b, 0, k) + h.check(t) +} + +// set up to k bits at index i and greater +func setbits(h *hashSet, b []byte, i int, k int) { + h.addB(b) + if k == 0 { + return + } + for j := i; j < len(b)*8; j++ { + b[j/8] |= byte(1 << uint(j&7)) + setbits(h, b, j+1, k-1) + b[j/8] &= byte(^(1 << uint(j&7))) + } +} + +// Test all possible combinations of n blocks from the set s. +// "permutation" is a bad name here, but it is what Smhasher uses. +func TestSmhasherPermutation(t *testing.T) { + if runtime.GOARCH == "wasm" { + t.Skip("Too slow on wasm") + } + if testing.Short() { + t.Skip("Skipping in short mode") + } + permutation(t, []uint32{0, 1, 2, 3, 4, 5, 6, 7}, 8) + permutation(t, []uint32{0, 1 << 29, 2 << 29, 3 << 29, 4 << 29, 5 << 29, 6 << 29, 7 << 29}, 8) + permutation(t, []uint32{0, 1}, 20) + permutation(t, []uint32{0, 1 << 31}, 20) + permutation(t, []uint32{0, 1, 2, 3, 4, 5, 6, 7, 1 << 29, 2 << 29, 3 << 29, 4 << 29, 5 << 29, 6 << 29, 7 << 29}, 6) +} +func permutation(t *testing.T, s []uint32, n int) { + b := make([]byte, n*4) + h := newHashSet() + genPerm(h, b, s, 0) + h.check(t) +} +func genPerm(h *hashSet, b []byte, s []uint32, n int) { + h.addB(b[:n]) + if n == len(b) { + return + } + for _, v := range s { + b[n] = byte(v) + b[n+1] = byte(v >> 8) + b[n+2] = byte(v >> 16) + b[n+3] = byte(v >> 24) + genPerm(h, b, s, n+4) + } +} + +type key interface { + clear() // set bits all to 0 + random(r *rand.Rand) // set key to something random + bits() int // how many bits key has + flipBit(i int) // flip bit i of the key + hash() uint64 // hash the key + name() string // for error reporting +} + +type bytesKey struct { + b []byte +} + +func (k *bytesKey) clear() { + for i := range k.b { + k.b[i] = 0 + } +} +func (k *bytesKey) random(r *rand.Rand) { + randBytes(r, k.b) +} +func (k *bytesKey) bits() int { + return len(k.b) * 8 +} +func (k *bytesKey) flipBit(i int) { + k.b[i>>3] ^= byte(1 << uint(i&7)) +} +func (k *bytesKey) hash() uint64 { + return bytesHash(k.b, 0) +} +func (k *bytesKey) name() string { + return fmt.Sprintf("bytes%d", len(k.b)) +} + +// Flipping a single bit of a key should flip each output bit with 50% probability. +func TestSmhasherAvalanche(t *testing.T) { + if runtime.GOARCH == "wasm" { + t.Skip("Too slow on wasm") + } + if testing.Short() { + t.Skip("Skipping in short mode") + } + avalancheTest1(t, &bytesKey{make([]byte, 2)}) + avalancheTest1(t, &bytesKey{make([]byte, 4)}) + avalancheTest1(t, &bytesKey{make([]byte, 8)}) + avalancheTest1(t, &bytesKey{make([]byte, 16)}) + avalancheTest1(t, &bytesKey{make([]byte, 32)}) + avalancheTest1(t, &bytesKey{make([]byte, 200)}) +} +func avalancheTest1(t *testing.T, k key) { + const REP = 100000 + r := rand.New(rand.NewSource(1234)) + n := k.bits() + + // grid[i][j] is a count of whether flipping + // input bit i affects output bit j. + grid := make([][hashSize]int, n) + + for z := 0; z < REP; z++ { + // pick a random key, hash it + k.random(r) + h := k.hash() + + // flip each bit, hash & compare the results + for i := 0; i < n; i++ { + k.flipBit(i) + d := h ^ k.hash() + k.flipBit(i) + + // record the effects of that bit flip + g := &grid[i] + for j := 0; j < hashSize; j++ { + g[j] += int(d & 1) + d >>= 1 + } + } + } + + // Each entry in the grid should be about REP/2. + // More precisely, we did N = k.bits() * hashSize experiments where + // each is the sum of REP coin flips. We want to find bounds on the + // sum of coin flips such that a truly random experiment would have + // all sums inside those bounds with 99% probability. + N := n * hashSize + var c float64 + // find c such that Prob(mean-c*stddev < x < mean+c*stddev)^N > .9999 + for c = 0.0; math.Pow(math.Erf(c/math.Sqrt(2)), float64(N)) < .9999; c += .1 { + } + c *= 4.0 // allowed slack - we don't need to be perfectly random + mean := .5 * REP + stddev := .5 * math.Sqrt(REP) + low := int(mean - c*stddev) + high := int(mean + c*stddev) + for i := 0; i < n; i++ { + for j := 0; j < hashSize; j++ { + x := grid[i][j] + if x < low || x > high { + t.Errorf("bad bias for %s bit %d -> bit %d: %d/%d\n", k.name(), i, j, x, REP) + } + } + } +} + +// All bit rotations of a set of distinct keys +func TestSmhasherWindowed(t *testing.T) { + windowed(t, &bytesKey{make([]byte, 128)}) +} +func windowed(t *testing.T, k key) { + if runtime.GOARCH == "wasm" { + t.Skip("Too slow on wasm") + } + if testing.Short() { + t.Skip("Skipping in short mode") + } + const BITS = 16 + + for r := 0; r < k.bits(); r++ { + h := newHashSet() + for i := 0; i < 1<>uint(j)&1 != 0 { + k.flipBit((j + r) % k.bits()) + } + } + h.add(k.hash()) + } + h.check(t) + } +} + +// All keys of the form prefix + [A-Za-z0-9]*N + suffix. +func TestSmhasherText(t *testing.T) { + if testing.Short() { + t.Skip("Skipping in short mode") + } + text(t, "Foo", "Bar") + text(t, "FooBar", "") + text(t, "", "FooBar") +} +func text(t *testing.T, prefix, suffix string) { + const N = 4 + const S = "ABCDEFGHIJKLMNOPQRSTabcdefghijklmnopqrst0123456789" + const L = len(S) + b := make([]byte, len(prefix)+N+len(suffix)) + copy(b, prefix) + copy(b[len(prefix)+N:], suffix) + h := newHashSet() + c := b[len(prefix):] + for i := 0; i < L; i++ { + c[0] = S[i] + for j := 0; j < L; j++ { + c[1] = S[j] + for k := 0; k < L; k++ { + c[2] = S[k] + for x := 0; x < L; x++ { + c[3] = S[x] + h.addB(b) + } + } + } + } + h.check(t) +} + +// Make sure different seed values generate different hashes. +func TestSmhasherSeed(t *testing.T) { + h := newHashSet() + const N = 100000 + s := "hello" + for i := 0; i < N; i++ { + h.addS_seed(s, uint64(i)) + h.addS_seed(s, uint64(i)<<32) // make sure high bits are used + } + h.check(t) +} diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go index fb862459c8a3ea..6b5772226ee44a 100644 --- a/src/go/build/deps_test.go +++ b/src/go/build/deps_test.go @@ -84,16 +84,18 @@ var pkgDeps = map[string][]string{ }, // L2 adds Unicode and strings processing. - "bufio": {"L0", "unicode/utf8", "bytes"}, - "bytes": {"L0", "unicode", "unicode/utf8"}, - "path": {"L0", "unicode/utf8", "strings"}, - "strings": {"L0", "unicode", "unicode/utf8"}, - "unicode": {}, + "bufio": {"L0", "unicode/utf8", "bytes"}, + "bytes": {"L0", "unicode", "unicode/utf8"}, + "bytes/hash": {"L0"}, + "path": {"L0", "unicode/utf8", "strings"}, + "strings": {"L0", "unicode", "unicode/utf8"}, + "unicode": {}, "L2": { "L1", "bufio", "bytes", + "bytes/hash", "path", "strings", "unicode", @@ -242,51 +244,51 @@ var pkgDeps = map[string][]string{ "go/types": {"L4", "GOPARSER", "container/heap", "go/constant"}, // One of a kind. - "archive/tar": {"L4", "OS", "syscall", "os/user"}, - "archive/zip": {"L4", "OS", "compress/flate"}, - "container/heap": {"sort"}, - "compress/bzip2": {"L4"}, - "compress/flate": {"L4"}, - "compress/gzip": {"L4", "compress/flate"}, - "compress/lzw": {"L4"}, - "compress/zlib": {"L4", "compress/flate"}, - "context": {"errors", "internal/reflectlite", "sync", "time"}, - "database/sql": {"L4", "container/list", "context", "database/sql/driver", "database/sql/internal"}, - "database/sql/driver": {"L4", "context", "time", "database/sql/internal"}, - "debug/dwarf": {"L4"}, - "debug/elf": {"L4", "OS", "debug/dwarf", "compress/zlib"}, - "debug/gosym": {"L4"}, - "debug/macho": {"L4", "OS", "debug/dwarf", "compress/zlib"}, - "debug/pe": {"L4", "OS", "debug/dwarf", "compress/zlib"}, - "debug/plan9obj": {"L4", "OS"}, - "encoding": {"L4"}, - "encoding/ascii85": {"L4"}, - "encoding/asn1": {"L4", "math/big"}, - "encoding/csv": {"L4"}, - "encoding/gob": {"L4", "OS", "encoding"}, - "encoding/hex": {"L4"}, - "encoding/json": {"L4", "encoding"}, - "encoding/pem": {"L4"}, - "encoding/xml": {"L4", "encoding"}, - "flag": {"L4", "OS"}, - "go/build": {"L4", "OS", "GOPARSER", "internal/goroot", "internal/goversion"}, - "html": {"L4"}, - "image/draw": {"L4", "image/internal/imageutil"}, - "image/gif": {"L4", "compress/lzw", "image/color/palette", "image/draw"}, - "image/internal/imageutil": {"L4"}, - "image/jpeg": {"L4", "image/internal/imageutil"}, - "image/png": {"L4", "compress/zlib"}, - "index/suffixarray": {"L4", "regexp"}, - "internal/goroot": {"L4", "OS"}, - "internal/singleflight": {"sync"}, - "internal/trace": {"L4", "OS", "container/heap"}, - "internal/xcoff": {"L4", "OS", "debug/dwarf"}, - "math/big": {"L4"}, - "mime": {"L4", "OS", "syscall", "internal/syscall/windows/registry"}, - "mime/quotedprintable": {"L4"}, - "net/internal/socktest": {"L4", "OS", "syscall", "internal/syscall/windows"}, - "net/url": {"L4"}, - "plugin": {"L0", "OS", "CGO"}, + "archive/tar": {"L4", "OS", "syscall", "os/user"}, + "archive/zip": {"L4", "OS", "compress/flate"}, + "container/heap": {"sort"}, + "compress/bzip2": {"L4"}, + "compress/flate": {"L4"}, + "compress/gzip": {"L4", "compress/flate"}, + "compress/lzw": {"L4"}, + "compress/zlib": {"L4", "compress/flate"}, + "context": {"errors", "internal/reflectlite", "sync", "time"}, + "database/sql": {"L4", "container/list", "context", "database/sql/driver", "database/sql/internal"}, + "database/sql/driver": {"L4", "context", "time", "database/sql/internal"}, + "debug/dwarf": {"L4"}, + "debug/elf": {"L4", "OS", "debug/dwarf", "compress/zlib"}, + "debug/gosym": {"L4"}, + "debug/macho": {"L4", "OS", "debug/dwarf", "compress/zlib"}, + "debug/pe": {"L4", "OS", "debug/dwarf", "compress/zlib"}, + "debug/plan9obj": {"L4", "OS"}, + "encoding": {"L4"}, + "encoding/ascii85": {"L4"}, + "encoding/asn1": {"L4", "math/big"}, + "encoding/csv": {"L4"}, + "encoding/gob": {"L4", "OS", "encoding"}, + "encoding/hex": {"L4"}, + "encoding/json": {"L4", "encoding"}, + "encoding/pem": {"L4"}, + "encoding/xml": {"L4", "encoding"}, + "flag": {"L4", "OS"}, + "go/build": {"L4", "OS", "GOPARSER", "internal/goroot", "internal/goversion"}, + "html": {"L4"}, + "image/draw": {"L4", "image/internal/imageutil"}, + "image/gif": {"L4", "compress/lzw", "image/color/palette", "image/draw"}, + "image/internal/imageutil": {"L4"}, + "image/jpeg": {"L4", "image/internal/imageutil"}, + "image/png": {"L4", "compress/zlib"}, + "index/suffixarray": {"L4", "regexp"}, + "internal/goroot": {"L4", "OS"}, + "internal/singleflight": {"sync"}, + "internal/trace": {"L4", "OS", "container/heap"}, + "internal/xcoff": {"L4", "OS", "debug/dwarf"}, + "math/big": {"L4"}, + "mime": {"L4", "OS", "syscall", "internal/syscall/windows/registry"}, + "mime/quotedprintable": {"L4"}, + "net/internal/socktest": {"L4", "OS", "syscall", "internal/syscall/windows"}, + "net/url": {"L4"}, + "plugin": {"L0", "OS", "CGO"}, "runtime/pprof/internal/profile": {"L4", "OS", "compress/gzip", "regexp"}, "testing/internal/testdeps": {"L4", "internal/testlog", "runtime/pprof", "regexp"}, "text/scanner": {"L4", "OS"},