cmd/compile: use more of internal/bisect in HashDebug

Using more of internal/bisect gives us more that will be deleted
from base/hashdebug.go when we have updated the tools that
need the old protocol. It is also cheaper: there is no allocation to
make a decision about whether to enable, and no locking unless
printing is needed.

Change-Id: I43ec398461205a1a9e988512a134ed6b3a3b1587
Reviewed-on: https://go-review.googlesource.com/c/go/+/493736
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Russ Cox 2023-05-08 23:18:38 -04:00
parent ffc4cc05f5
commit da5a3146ec
5 changed files with 132 additions and 187 deletions

View File

@ -6,7 +6,6 @@ package base
import (
"bytes"
"cmd/internal/notsha256"
"cmd/internal/obj"
"cmd/internal/src"
"fmt"
@ -19,11 +18,6 @@ import (
"sync"
)
type writeSyncer interface {
io.Writer
Sync() error
}
type hashAndMask struct {
// a hash h matches if (h^hash)&mask == 0
hash uint64
@ -36,7 +30,7 @@ type HashDebug struct {
name string // base name of the flag/variable.
// what file (if any) receives the yes/no logging?
// default is os.Stdout
logfile writeSyncer
logfile io.Writer
posTmp []src.Pos
bytesTmp bytes.Buffer
matches []hashAndMask // A hash matches if one of these matches.
@ -70,7 +64,7 @@ var hashDebug *HashDebug
var FmaHash *HashDebug // for debugging fused-multiply-add floating point changes
var LoopVarHash *HashDebug // for debugging shared/private loop variable changes
// DebugHashMatch reports whether debug variable Gossahash
// DebugHashMatchPkgFunc reports whether debug variable Gossahash
//
// 1. is empty (returns true; this is a special more-quickly implemented case of 4 below)
//
@ -99,7 +93,7 @@ var LoopVarHash *HashDebug // for debugging shared/private loop variable changes
//
// Otherwise it returns false.
//
// Unless Flags.Gossahash is empty, when DebugHashMatch returns true the message
// Unless Flags.Gossahash is empty, when DebugHashMatchPkgFunc returns true the message
//
// "%s triggered %s\n", varname, pkgAndName
//
@ -135,12 +129,12 @@ var LoopVarHash *HashDebug // for debugging shared/private loop variable changes
//
// 6. gossahash should return a single function whose miscompilation
// causes the problem, and you can focus on that.
func DebugHashMatch(pkgAndName string) bool {
return hashDebug.DebugHashMatch(pkgAndName)
func DebugHashMatchPkgFunc(pkg, fn string) bool {
return hashDebug.MatchPkgFunc(pkg, fn)
}
func DebugHashMatchPos(pos src.XPos) bool {
return hashDebug.DebugHashMatchPos(pos)
return hashDebug.MatchPos(pos)
}
// HasDebugHash returns true if Flags.Gossahash is non-empty, which
@ -150,6 +144,7 @@ func HasDebugHash() bool {
return hashDebug != nil
}
// TODO: Delete when we switch to bisect-only.
func toHashAndMask(s, varname string) hashAndMask {
l := len(s)
if l > 64 {
@ -168,7 +163,7 @@ func toHashAndMask(s, varname string) hashAndMask {
// NewHashDebug returns a new hash-debug tester for the
// environment variable ev. If ev is not set, it returns
// nil, allowing a lightweight check for normal-case behavior.
func NewHashDebug(ev, s string, file writeSyncer) *HashDebug {
func NewHashDebug(ev, s string, file io.Writer) *HashDebug {
if s == "" {
return nil
}
@ -182,6 +177,8 @@ func NewHashDebug(ev, s string, file writeSyncer) *HashDebug {
hd.bisect = m
return hd
}
// TODO: Delete remainder of function when we switch to bisect-only.
ss := strings.Split(s, "/")
// first remove any leading exclusions; these are preceded with "-"
i := 0
@ -217,43 +214,7 @@ func NewHashDebug(ev, s string, file writeSyncer) *HashDebug {
}
func hashOf(pkgAndName string, param uint64) uint64 {
return hashOfBytes([]byte(pkgAndName), param)
}
func hashOfBytes(sbytes []byte, param uint64) uint64 {
hbytes := notsha256.Sum256(sbytes)
hash := uint64(hbytes[7])<<56 + uint64(hbytes[6])<<48 +
uint64(hbytes[5])<<40 + uint64(hbytes[4])<<32 +
uint64(hbytes[3])<<24 + uint64(hbytes[2])<<16 +
uint64(hbytes[1])<<8 + uint64(hbytes[0])
if param != 0 {
// Because param is probably a line number, probably near zero,
// hash it up a little bit, but even so only the lower-order bits
// likely matter because search focuses on those.
p0 := param + uint64(hbytes[9]) + uint64(hbytes[10])<<8 +
uint64(hbytes[11])<<16 + uint64(hbytes[12])<<24
p1 := param + uint64(hbytes[13]) + uint64(hbytes[14])<<8 +
uint64(hbytes[15])<<16 + uint64(hbytes[16])<<24
param += p0 * p1
param ^= param>>17 ^ param<<47
}
return hash ^ param
}
// DebugHashMatch returns true if either the variable used to create d is
// unset, or if its value is y, or if it is a suffix of the base-two
// representation of the hash of pkgAndName. If the variable is not nil,
// then a true result is accompanied by stylized output to d.logfile, which
// is used for automated bug search.
func (d *HashDebug) DebugHashMatch(pkgAndName string) bool {
return d.DebugHashMatchParam(pkgAndName, 0)
}
// TODO: Delete when we switch to bisect-only.
func (d *HashDebug) excluded(hash uint64) bool {
for _, m := range d.excludes {
if (m.hash^hash)&m.mask == 0 {
@ -263,6 +224,7 @@ func (d *HashDebug) excluded(hash uint64) bool {
return false
}
// TODO: Delete when we switch to bisect-only.
func hashString(hash uint64) string {
hstr := ""
if hash == 0 {
@ -272,9 +234,13 @@ func hashString(hash uint64) string {
hstr = string('0'+byte(hash&1)) + hstr
}
}
if len(hstr) > 24 {
hstr = hstr[len(hstr)-24:]
}
return hstr
}
// TODO: Delete when we switch to bisect-only.
func (d *HashDebug) match(hash uint64) *hashAndMask {
for i, m := range d.matches {
if (m.hash^hash)&m.mask == 0 {
@ -284,102 +250,118 @@ func (d *HashDebug) match(hash uint64) *hashAndMask {
return nil
}
// DebugHashMatchParam returns true if either the variable used to create d is
// MatchPkgFunc returns true if either the variable used to create d is
// unset, or if its value is y, or if it is a suffix of the base-two
// representation of the hash of pkgAndName and param. If the variable is not
// nil, then a true result is accompanied by stylized output to d.logfile,
// which is used for automated bug search.
func (d *HashDebug) DebugHashMatchParam(pkgAndName string, param uint64) bool {
// representation of the hash of pkg and fn. If the variable is not nil,
// then a true result is accompanied by stylized output to d.logfile, which
// is used for automated bug search.
func (d *HashDebug) MatchPkgFunc(pkg, fn string) bool {
if d == nil {
return true
}
// Written this way to make inlining likely.
return d.matchPkgFunc(pkg, fn)
}
hash := hashOf(pkgAndName, param)
func (d *HashDebug) matchPkgFunc(pkg, fn string) bool {
hash := bisect.Hash(pkg, fn)
if d.bisect != nil {
if d.bisect.ShouldPrint(hash) {
d.logDebugHashMatch(d.name, pkgAndName, hash, param)
d.log(d.name, hash, pkg+"."+fn)
}
return d.bisect.ShouldEnable(hash)
}
// TODO: Delete rest of function body when we switch to bisect-only.
if m := d.match(hash); m != nil {
d.logDebugHashMatch(m.name, pkgAndName, hash, param)
d.log(m.name, hash, pkg+"."+fn)
return true
}
return false
}
// DebugHashMatchPos is similar to DebugHashMatchParam, but for hash computation
// MatchPos is similar to MatchPkgFunc, but for hash computation
// it uses the source position including all inlining information instead of
// package name and path. The mutex locking is more frequent and more granular.
// package name and path.
// Note that the default answer for no environment variable (d == nil)
// is "yes", do the thing.
func (d *HashDebug) DebugHashMatchPos(pos src.XPos) bool {
func (d *HashDebug) MatchPos(pos src.XPos) bool {
if d == nil {
return true
}
// Written this way to make inlining likely.
return d.debugHashMatchPos(Ctxt, pos)
return d.matchPos(Ctxt, pos)
}
func (d *HashDebug) debugHashMatchPos(ctxt *obj.Link, pos src.XPos) bool {
// TODO: When we remove the old d.match code, we can use
// d.bisect.Hash instead of the locked buffer, and we can
// use d.bisect.MarkerOnly to decide whether to format a string.
d.mu.Lock()
defer d.mu.Unlock()
func (d *HashDebug) matchPos(ctxt *obj.Link, pos src.XPos) bool {
hash := d.hashPos(ctxt, pos)
b := d.bytesForPos(ctxt, pos)
hash := hashOfBytes(b, 0)
if d.bisect != nil {
if d.bisect.ShouldPrint(hash) {
d.logDebugHashMatchLocked(d.name, string(b), hash, 0)
d.log(d.name, hash, d.fmtPos(ctxt, pos))
}
return d.bisect.ShouldEnable(hash)
}
// TODO: Delete rest of function body when we switch to bisect-only.
// Return false for explicitly excluded hashes
if d.excluded(hash) {
return false
}
if m := d.match(hash); m != nil {
d.logDebugHashMatchLocked(m.name, string(b), hash, 0)
d.log(m.name, hash, d.fmtPos(ctxt, pos))
return true
}
return false
}
// bytesForPos renders a position, including inlining, into d.bytesTmp
// and returns the byte array. d.mu must be locked.
func (d *HashDebug) bytesForPos(ctxt *obj.Link, pos src.XPos) []byte {
b := &d.bytesTmp
b.Reset()
format := func(p src.Pos) {
f := p.Filename()
if d.fileSuffixOnly {
f = filepath.Base(f)
}
fmt.Fprintf(b, "%s:%d:%d", f, p.Line(), p.Col())
// short returns the form of file name to use for d.
// The default is the full path, but fileSuffixOnly selects
// just the final path element.
func (d *HashDebug) short(name string) string {
if d.fileSuffixOnly {
return filepath.Base(name)
}
return name
}
// hashPos returns a hash of the position pos, including its entire inline stack.
// If d.inlineSuffixOnly is true, hashPos only considers the innermost (leaf) position on the inline stack.
func (d *HashDebug) hashPos(ctxt *obj.Link, pos src.XPos) uint64 {
if d.inlineSuffixOnly {
p := ctxt.InnermostPos(pos)
return bisect.Hash(d.short(p.Filename()), p.Line(), p.Col())
}
h := bisect.Hash()
ctxt.AllPos(pos, func(p src.Pos) {
h = bisect.Hash(h, d.short(p.Filename()), p.Line(), p.Col())
})
return h
}
// fmtPos returns a textual formatting of the position pos, including its entire inline stack.
// If d.inlineSuffixOnly is true, fmtPos only considers the innermost (leaf) position on the inline stack.
func (d *HashDebug) fmtPos(ctxt *obj.Link, pos src.XPos) string {
format := func(p src.Pos) string {
return fmt.Sprintf("%s:%d:%d", d.short(p.Filename()), p.Line(), p.Col())
}
if d.inlineSuffixOnly {
format(ctxt.InnermostPos(pos))
} else {
ctxt.AllPos(pos, func(p src.Pos) {
if b.Len() > 0 {
b.WriteByte(';')
}
format(p)
})
return format(ctxt.InnermostPos(pos))
}
return b.Bytes()
var stk []string
ctxt.AllPos(pos, func(p src.Pos) {
stk = append(stk, format(p))
})
return strings.Join(stk, "; ")
}
func (d *HashDebug) logDebugHashMatch(varname, name string, hash, param uint64) {
// log prints a match with the given hash and textual formatting.
// TODO: Delete varname parameter when we switch to bisect-only.
func (d *HashDebug) log(varname string, hash uint64, text string) {
d.mu.Lock()
defer d.mu.Unlock()
d.logDebugHashMatchLocked(varname, name, hash, param)
}
func (d *HashDebug) logDebugHashMatchLocked(varname, name string, hash, param uint64) {
file := d.logfile
if file == nil {
if tmpfile := os.Getenv("GSHS_LOGFILE"); tmpfile != "" {
@ -395,21 +377,11 @@ func (d *HashDebug) logDebugHashMatchLocked(varname, name string, hash, param ui
}
d.logfile = file
}
hstr := hashString(hash)
if len(hstr) > 24 {
hstr = hstr[len(hstr)-24:]
}
// External tools depend on this string
if param == 0 {
fmt.Fprintf(file, "%s triggered %s %s\n", varname, name, hstr)
} else {
fmt.Fprintf(file, "%s triggered %s:%d %s\n", varname, name, param, hstr)
}
// Print new bisect version too.
if param == 0 {
fmt.Fprintf(file, "%s %s\n", name, bisect.Marker(hash))
} else {
fmt.Fprintf(file, "%s:%d %s\n", name, param, bisect.Marker(hash))
}
file.Sync()
// Bisect output.
fmt.Fprintf(file, "%s %s\n", text, bisect.Marker(hash))
// Gossahash output.
// TODO: Delete rest of function when we switch to bisect-only.
fmt.Fprintf(file, "%s triggered %s %s\n", varname, text, hashString(hash))
}

View File

@ -6,26 +6,27 @@ package base
import (
"bytes"
"internal/bisect"
"strings"
"testing"
)
func TestHashDebugGossahashY(t *testing.T) {
hd := NewHashDebug("GOSSAHASH", "y", new(bufferWithSync))
hd := NewHashDebug("GOSSAHASH", "y", new(bytes.Buffer))
if hd == nil {
t.Errorf("NewHashDebug should not return nil for GOSSASHASH=y")
}
if !hd.DebugHashMatch("anything") {
if !hd.MatchPkgFunc("anything", "anyfunc") {
t.Errorf("NewHashDebug should return yes for everything for GOSSASHASH=y")
}
}
func TestHashDebugGossahashN(t *testing.T) {
hd := NewHashDebug("GOSSAHASH", "n", new(bufferWithSync))
hd := NewHashDebug("GOSSAHASH", "n", new(bytes.Buffer))
if hd == nil {
t.Errorf("NewHashDebug should not return nil for GOSSASHASH=n")
}
if hd.DebugHashMatch("anything") {
if hd.MatchPkgFunc("anything", "anyfunc") {
t.Errorf("NewHashDebug should return no for everything for GOSSASHASH=n")
}
}
@ -49,74 +50,61 @@ func TestHashDebugMagic(t *testing.T) {
}
func TestHash(t *testing.T) {
h0 := hashOf("bar", 0)
h1 := hashOf("bar", 1)
t.Logf(`These values are used in other tests: hashOf("bar,0)"=0x%x, hashOf("bar,1)"=0x%x`, h0, h1)
h0 := bisect.Hash("bar", "0")
h1 := bisect.Hash("bar", "1")
t.Logf(`These values are used in other tests: Hash("bar", "0")=%#64b, Hash("bar", "1")=%#64b`, h0, h1)
if h0 == h1 {
t.Errorf("Hashes 0x%x and 0x%x should differ", h0, h1)
}
}
func TestHashMatch(t *testing.T) {
ws := new(bufferWithSync)
hd := NewHashDebug("GOSSAHASH", "0011", ws)
check := hd.DebugHashMatch("bar")
msg := ws.String()
b := new(bytes.Buffer)
hd := NewHashDebug("GOSSAHASH", "1110", b)
check := hd.MatchPkgFunc("bar", "0")
msg := b.String()
t.Logf("message was '%s'", msg)
if !check {
t.Errorf("GOSSAHASH=0011 should have matched for 'bar'")
t.Errorf("GOSSAHASH=1110 should have matched for 'bar', '0'")
}
wantPrefix(t, msg, "GOSSAHASH triggered bar ")
wantContains(t, msg, "\nbar [bisect-match ")
}
func TestHashMatchParam(t *testing.T) {
ws := new(bufferWithSync)
hd := NewHashDebug("GOSSAHASH", "1010", ws)
check := hd.DebugHashMatchParam("bar", 1)
msg := ws.String()
t.Logf("message was '%s'", msg)
if !check {
t.Errorf("GOSSAHASH=1010 should have matched for 'bar', 1")
}
wantPrefix(t, msg, "GOSSAHASH triggered bar:1 ")
wantContains(t, msg, "\nbar:1 [bisect-match ")
wantPrefix(t, msg, "bar.0 [bisect-match ")
wantContains(t, msg, "\nGOSSAHASH triggered bar.0 ")
}
func TestYMatch(t *testing.T) {
ws := new(bufferWithSync)
hd := NewHashDebug("GOSSAHASH", "y", ws)
check := hd.DebugHashMatch("bar")
msg := ws.String()
b := new(bytes.Buffer)
hd := NewHashDebug("GOSSAHASH", "y", b)
check := hd.MatchPkgFunc("bar", "0")
msg := b.String()
t.Logf("message was '%s'", msg)
if !check {
t.Errorf("GOSSAHASH=y should have matched for 'bar'")
t.Errorf("GOSSAHASH=y should have matched for 'bar', '0'")
}
wantPrefix(t, msg, "GOSSAHASH triggered bar 110101000010000100000011")
wantContains(t, msg, "\nbar [bisect-match ")
wantPrefix(t, msg, "bar.0 [bisect-match ")
wantContains(t, msg, "\nGOSSAHASH triggered bar.0 010100100011100101011110")
}
func TestNMatch(t *testing.T) {
ws := new(bufferWithSync)
hd := NewHashDebug("GOSSAHASH", "n", ws)
check := hd.DebugHashMatch("bar")
msg := ws.String()
b := new(bytes.Buffer)
hd := NewHashDebug("GOSSAHASH", "n", b)
check := hd.MatchPkgFunc("bar", "0")
msg := b.String()
t.Logf("message was '%s'", msg)
if check {
t.Errorf("GOSSAHASH=n should NOT have matched for 'bar'")
t.Errorf("GOSSAHASH=n should NOT have matched for 'bar', '0'")
}
wantPrefix(t, msg, "GOSSAHASH triggered bar 110101000010000100000011")
wantContains(t, msg, "\nbar [bisect-match ")
wantPrefix(t, msg, "bar.0 [bisect-match ")
wantContains(t, msg, "\nGOSSAHASH triggered bar.0 010100100011100101011110")
}
func TestHashNoMatch(t *testing.T) {
ws := new(bufferWithSync)
hd := NewHashDebug("GOSSAHASH", "001100", ws)
check := hd.DebugHashMatch("bar")
msg := ws.String()
b := new(bytes.Buffer)
hd := NewHashDebug("GOSSAHASH", "01110", b)
check := hd.MatchPkgFunc("bar", "0")
msg := b.String()
t.Logf("message was '%s'", msg)
if check {
t.Errorf("GOSSAHASH=001100 should NOT have matched for 'bar'")
t.Errorf("GOSSAHASH=001100 should NOT have matched for 'bar', '0'")
}
if msg != "" {
t.Errorf("Message should have been empty, instead %s", msg)
@ -125,41 +113,27 @@ func TestHashNoMatch(t *testing.T) {
}
func TestHashSecondMatch(t *testing.T) {
ws := new(bufferWithSync)
hd := NewHashDebug("GOSSAHASH", "001100/0011", ws)
b := new(bytes.Buffer)
hd := NewHashDebug("GOSSAHASH", "01110/11110", b)
check := hd.DebugHashMatch("bar")
msg := ws.String()
check := hd.MatchPkgFunc("bar", "0")
msg := b.String()
t.Logf("message was '%s'", msg)
if !check {
t.Errorf("GOSSAHASH=001100, GOSSAHASH0=0011 should have matched for 'bar'")
t.Errorf("GOSSAHASH=001100, GOSSAHASH0=0011 should have matched for 'bar', '0'")
}
wantPrefix(t, msg, "GOSSAHASH0 triggered bar")
}
type bufferWithSync struct {
b bytes.Buffer
}
func (ws *bufferWithSync) Sync() error {
return nil
}
func (ws *bufferWithSync) Write(p []byte) (n int, err error) {
return (&ws.b).Write(p)
}
func (ws *bufferWithSync) String() string {
return strings.TrimSpace((&ws.b).String())
wantContains(t, msg, "\nGOSSAHASH0 triggered bar")
}
func wantPrefix(t *testing.T, got, want string) {
t.Helper()
if !strings.HasPrefix(got, want) {
t.Errorf("want prefix %q, got:\n%s", want, got)
}
}
func wantContains(t *testing.T, got, want string) {
t.Helper()
if !strings.Contains(got, want) {
t.Errorf("want contains %q, got:\n%s", want, got)
}

View File

@ -91,7 +91,7 @@ func ForCapture(fn *ir.Func) []VarAndLoop {
// subject to hash-variable debugging.
maybeReplaceVar := func(k ir.Node, x *ir.RangeStmt) ir.Node {
if n, ok := k.(*ir.Name); ok && possiblyLeaked[n] {
if base.LoopVarHash.DebugHashMatchPos(n.Pos()) {
if base.LoopVarHash.MatchPos(n.Pos()) {
// Rename the loop key, prefix body with assignment from loop key
transformed = append(transformed, VarAndLoop{n, x, lastPos})
tk := typecheck.Temp(n.Type())
@ -199,7 +199,7 @@ func ForCapture(fn *ir.Func) []VarAndLoop {
forAllDefInInit(x, func(z ir.Node) {
if n, ok := z.(*ir.Name); ok && possiblyLeaked[n] {
// Hash on n.Pos() for most precise failure location.
if base.LoopVarHash.DebugHashMatchPos(n.Pos()) {
if base.LoopVarHash.MatchPos(n.Pos()) {
leaked = append(leaked, n)
}
}

View File

@ -190,7 +190,7 @@ func TestLoopVarHashes(t *testing.T) {
return string(b)
}
m := f("000100000010011111101100")
m := f("011011011110011110111101")
t.Logf(m)
mCount := strings.Count(m, "loopvarhash triggered main.go:27:6")

View File

@ -773,8 +773,7 @@ func (f *Func) DebugHashMatch() bool {
if !base.HasDebugHash() {
return true
}
name := f.fe.MyImportPath() + "." + f.Name
return base.DebugHashMatch(name)
return base.DebugHashMatchPkgFunc(f.fe.MyImportPath(), f.Name)
}
func (f *Func) spSb() (sp, sb *Value) {
@ -808,5 +807,5 @@ func (f *Func) useFMA(v *Value) bool {
if base.FmaHash == nil {
return true
}
return base.FmaHash.DebugHashMatchPos(v.Pos)
return base.FmaHash.MatchPos(v.Pos)
}