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// Copyright 2023 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.
// Code generated by "gen.bash" from internal/trace/v2; DO NOT EDIT.
//go:build go1.21
package trace
import (
// EventKind indicates the kind of event this is.
// Use this information to obtain a more specific event that
// allows access to more detailed information.
type EventKind uint16
const (
EventBad EventKind = iota
// EventKindSync is an event that indicates a global synchronization
// point in the trace. At the point of a sync event, the
// trace reader can be certain that all resources (e.g. threads,
// goroutines) that have existed until that point have been enumerated.
// EventMetric is an event that represents the value of a metric at
// a particular point in time.
// EventLabel attaches a label to a resource.
// EventStackSample represents an execution sample, indicating what a
// thread/proc/goroutine was doing at a particular point in time via
// its backtrace.
// Note: Samples should be considered a close approximation of
// what a thread/proc/goroutine was executing at a given point in time.
// These events may slightly contradict the situation StateTransitions
// describe, so they should only be treated as a best-effort annotation.
// EventRangeBegin and EventRangeEnd are a pair of generic events representing
// a special range of time. Ranges are named and scoped to some resource
// (identified via ResourceKind). A range that has begun but has not ended
// is considered active.
// EvRangeBegin and EvRangeEnd will share the same name, and an End will always
// follow a Begin on the same instance of the resource. The associated
// resource ID can be obtained from the Event. ResourceNone indicates the
// range is globally scoped. That is, any goroutine/proc/thread can start or
// stop, but only one such range may be active at any given time.
// EventRangeActive is like EventRangeBegin, but indicates that the range was
// already active. In this case, the resource referenced may not be in the current
// context.
// EvTaskBegin and EvTaskEnd are a pair of events representing a runtime/trace.Task.
// EventRegionBegin and EventRegionEnd are a pair of events represent a runtime/trace.Region.
// EventLog represents a runtime/trace.Log call.
// Transitions in state for some resource.
// String returns a string form of the EventKind.
func (e EventKind) String() string {
if int(e) >= len(eventKindStrings) {
return eventKindStrings[0]
return eventKindStrings[e]
var eventKindStrings = [...]string{
EventBad: "Bad",
EventSync: "Sync",
EventMetric: "Metric",
EventLabel: "Label",
EventStackSample: "StackSample",
EventRangeBegin: "RangeBegin",
EventRangeActive: "RangeActive",
EventRangeEnd: "RangeEnd",
EventTaskBegin: "TaskBegin",
EventTaskEnd: "TaskEnd",
EventRegionBegin: "RegionBegin",
EventRegionEnd: "RegionEnd",
EventLog: "Log",
EventStateTransition: "StateTransition",
const maxTime = Time(math.MaxInt64)
// Time is a timestamp in nanoseconds.
// It corresponds to the monotonic clock on the platform that the
// trace was taken, and so is possible to correlate with timestamps
// for other traces taken on the same machine using the same clock
// (i.e. no reboots in between).
// The actual absolute value of the timestamp is only meaningful in
// relation to other timestamps from the same clock.
// BUG: Timestamps coming from traces on Windows platforms are
// only comparable with timestamps from the same trace. Timestamps
// across traces cannot be compared, because the system clock is
// not used as of Go 1.22.
// BUG: Traces produced by Go versions 1.21 and earlier cannot be
// compared with timestamps from other traces taken on the same
// machine. This is because the system clock was not used at all
// to collect those timestamps.
type Time int64
// Sub subtracts t0 from t, returning the duration in nanoseconds.
func (t Time) Sub(t0 Time) time.Duration {
return time.Duration(int64(t) - int64(t0))
// Metric provides details about a Metric event.
type Metric struct {
// Name is the name of the sampled metric.
// Names follow the same convention as metric names in the
// runtime/metrics package, meaning they include the unit.
// Names that match with the runtime/metrics package represent
// the same quantity. Note that this corresponds to the
// runtime/metrics package for the Go version this trace was
// collected for.
Name string
// Value is the sampled value of the metric.
// The Value's Kind is tied to the name of the metric, and so is
// guaranteed to be the same for metric samples for the same metric.
Value Value
// Label provides details about a Label event.
type Label struct {
// Label is the label applied to some resource.
Label string
// Resource is the resource to which this label should be applied.
Resource ResourceID
// Range provides details about a Range event.
type Range struct {
// Name is a human-readable name for the range.
// This name can be used to identify the end of the range for the resource
// its scoped to, because only one of each type of range may be active on
// a particular resource. The relevant resource should be obtained from the
// Event that produced these details. The corresponding RangeEnd will have
// an identical name.
Name string
// Scope is the resource that the range is scoped to.
// For example, a ResourceGoroutine scope means that the same goroutine
// must have a start and end for the range, and that goroutine can only
// have one range of a particular name active at any given time. The
// ID that this range is scoped to may be obtained via Event.Goroutine.
// The ResourceNone scope means that the range is globally scoped. As a
// result, any goroutine/proc/thread may start or end the range, and only
// one such named range may be active globally at any given time.
// For RangeBegin and RangeEnd events, this will always reference some
// resource ID in the current execution context. For RangeActive events,
// this may reference a resource not in the current context. Prefer Scope
// over the current execution context.
Scope ResourceID
// RangeAttributes provides attributes about a completed Range.
type RangeAttribute struct {
// Name is the human-readable name for the range.
Name string
// Value is the value of the attribute.
Value Value
// TaskID is the internal ID of a task used to disambiguate tasks (even if they
// are of the same type).
type TaskID uint64
const (
// NoTask indicates the lack of a task.
NoTask = TaskID(^uint64(0))
// BackgroundTask is the global task that events are attached to if there was
// no other task in the context at the point the event was emitted.
BackgroundTask = TaskID(0)
// Task provides details about a Task event.
type Task struct {
// ID is a unique identifier for the task.
// This can be used to associate the beginning of a task with its end.
// ParentID is the ID of the parent task.
Parent TaskID
// Type is the taskType that was passed to runtime/trace.NewTask.
// May be "" if a task's TaskBegin event isn't present in the trace.
Type string
// Region provides details about a Region event.
type Region struct {
// Task is the ID of the task this region is associated with.
Task TaskID
// Type is the regionType that was passed to runtime/trace.StartRegion or runtime/trace.WithRegion.
Type string
// Log provides details about a Log event.
type Log struct {
// Task is the ID of the task this region is associated with.
Task TaskID
// Category is the category that was passed to runtime/trace.Log or runtime/trace.Logf.
Category string
// Message is the message that was passed to runtime/trace.Log or runtime/trace.Logf.
Message string
// Stack represents a stack. It's really a handle to a stack and it's trivially comparable.
// If two Stacks are equal then their Frames are guaranteed to be identical. If they are not
// equal, however, their Frames may still be equal.
type Stack struct {
table *evTable
id stackID
// Frames is an iterator over the frames in a Stack.
func (s Stack) Frames(yield func(f StackFrame) bool) bool {
if == 0 {
return true
stk := s.table.stacks.mustGet(
for _, pc := range stk.pcs {
f := s.table.pcs[pc]
sf := StackFrame{
PC: f.pc,
Func: s.table.strings.mustGet(f.funcID),
File: s.table.strings.mustGet(f.fileID),
Line: f.line,
if !yield(sf) {
return false
return true
// NoStack is a sentinel value that can be compared against any Stack value, indicating
// a lack of a stack trace.
var NoStack = Stack{}
// StackFrame represents a single frame of a stack.
type StackFrame struct {
// PC is the program counter of the function call if this
// is not a leaf frame. If it's a leaf frame, it's the point
// at which the stack trace was taken.
PC uint64
// Func is the name of the function this frame maps to.
Func string
// File is the file which contains the source code of Func.
File string
// Line is the line number within File which maps to PC.
Line uint64
// Event represents a single event in the trace.
type Event struct {
table *evTable
ctx schedCtx
base baseEvent
// Kind returns the kind of event that this is.
func (e Event) Kind() EventKind {
return go122Type2Kind[e.base.typ]
// Time returns the timestamp of the event.
func (e Event) Time() Time {
return e.base.time
// Goroutine returns the ID of the goroutine that was executing when
// this event happened. It describes part of the execution context
// for this event.
// Note that for goroutine state transitions this always refers to the
// state before the transition. For example, if a goroutine is just
// starting to run on this thread and/or proc, then this will return
// NoGoroutine. In this case, the goroutine starting to run will be
// can be found at Event.StateTransition().Resource.
func (e Event) Goroutine() GoID {
return e.ctx.G
// Proc returns the ID of the proc this event event pertains to.
// Note that for proc state transitions this always refers to the
// state before the transition. For example, if a proc is just
// starting to run on this thread, then this will return NoProc.
func (e Event) Proc() ProcID {
return e.ctx.P
// Thread returns the ID of the thread this event pertains to.
// Note that for thread state transitions this always refers to the
// state before the transition. For example, if a thread is just
// starting to run, then this will return NoThread.
// Note: tracking thread state is not currently supported, so this
// will always return a valid thread ID. However thread state transitions
// may be tracked in the future, and callers must be robust to this
// possibility.
func (e Event) Thread() ThreadID {
return e.ctx.M
// Stack returns a handle to a stack associated with the event.
// This represents a stack trace at the current moment in time for
// the current execution context.
func (e Event) Stack() Stack {
if e.base.typ == evSync {
return NoStack
if e.base.typ == go122.EvCPUSample {
return Stack{table: e.table, id: stackID(e.base.args[0])}
spec := go122.Specs()[e.base.typ]
if len(spec.StackIDs) == 0 {
return NoStack
// The stack for the main execution context is always the
// first stack listed in StackIDs. Subtract one from this
// because we've peeled away the timestamp argument.
id := stackID(e.base.args[spec.StackIDs[0]-1])
if id == 0 {
return NoStack
return Stack{table: e.table, id: id}
// Metric returns details about a Metric event.
// Panics if Kind != EventMetric.
func (e Event) Metric() Metric {
if e.Kind() != EventMetric {
panic("Metric called on non-Metric event")
var m Metric
switch e.base.typ {
case go122.EvProcsChange:
m.Name = "/sched/gomaxprocs:threads"
m.Value = Value{kind: ValueUint64, scalar: e.base.args[0]}
case go122.EvHeapAlloc:
m.Name = "/memory/classes/heap/objects:bytes"
m.Value = Value{kind: ValueUint64, scalar: e.base.args[0]}
case go122.EvHeapGoal:
m.Name = "/gc/heap/goal:bytes"
m.Value = Value{kind: ValueUint64, scalar: e.base.args[0]}
panic(fmt.Sprintf("internal error: unexpected event type for Metric kind: %s", go122.EventString(e.base.typ)))
return m
// Label returns details about a Label event.
// Panics if Kind != EventLabel.
func (e Event) Label() Label {
if e.Kind() != EventLabel {
panic("Label called on non-Label event")
if e.base.typ != go122.EvGoLabel {
panic(fmt.Sprintf("internal error: unexpected event type for Label kind: %s", go122.EventString(e.base.typ)))
return Label{
Label: e.table.strings.mustGet(stringID(e.base.args[0])),
Resource: ResourceID{Kind: ResourceGoroutine, id: int64(e.ctx.G)},
// Range returns details about an EventRangeBegin, EventRangeActive, or EventRangeEnd event.
// Panics if Kind != EventRangeBegin, Kind != EventRangeActive, and Kind != EventRangeEnd.
func (e Event) Range() Range {
if kind := e.Kind(); kind != EventRangeBegin && kind != EventRangeActive && kind != EventRangeEnd {
panic("Range called on non-Range event")
var r Range
switch e.base.typ {
case go122.EvSTWBegin, go122.EvSTWEnd:
// N.B. ordering.advance smuggles in the STW reason as e.base.args[0]
// for go122.EvSTWEnd (it's already there for Begin).
r.Name = "stop-the-world (" + e.table.strings.mustGet(stringID(e.base.args[0])) + ")"
r.Scope = ResourceID{Kind: ResourceGoroutine, id: int64(e.Goroutine())}
case go122.EvGCBegin, go122.EvGCActive, go122.EvGCEnd:
r.Name = "GC concurrent mark phase"
r.Scope = ResourceID{Kind: ResourceNone}
case go122.EvGCSweepBegin, go122.EvGCSweepActive, go122.EvGCSweepEnd:
r.Name = "GC incremental sweep"
r.Scope = ResourceID{Kind: ResourceProc}
if e.base.typ == go122.EvGCSweepActive { = int64(e.base.args[0])
} else { = int64(e.Proc())
} = int64(e.Proc())
case go122.EvGCMarkAssistBegin, go122.EvGCMarkAssistActive, go122.EvGCMarkAssistEnd:
r.Name = "GC mark assist"
r.Scope = ResourceID{Kind: ResourceGoroutine}
if e.base.typ == go122.EvGCMarkAssistActive { = int64(e.base.args[0])
} else { = int64(e.Goroutine())
panic(fmt.Sprintf("internal error: unexpected event type for Range kind: %s", go122.EventString(e.base.typ)))
return r
// RangeAttributes returns attributes for a completed range.
// Panics if Kind != EventRangeEnd.
func (e Event) RangeAttributes() []RangeAttribute {
if e.Kind() != EventRangeEnd {
panic("Range called on non-Range event")
if e.base.typ != go122.EvGCSweepEnd {
return nil
return []RangeAttribute{
Name: "bytes swept",
Value: Value{kind: ValueUint64, scalar: e.base.args[0]},
Name: "bytes reclaimed",
Value: Value{kind: ValueUint64, scalar: e.base.args[1]},
// Task returns details about a TaskBegin or TaskEnd event.
// Panics if Kind != EventTaskBegin and Kind != EventTaskEnd.
func (e Event) Task() Task {
if kind := e.Kind(); kind != EventTaskBegin && kind != EventTaskEnd {
panic("Task called on non-Task event")
parentID := NoTask
var typ string
switch e.base.typ {
case go122.EvUserTaskBegin:
parentID = TaskID(e.base.args[1])
typ = e.table.strings.mustGet(stringID(e.base.args[2]))
case go122.EvUserTaskEnd:
parentID = TaskID(e.base.extra(version.Go122)[0])
typ = e.table.getExtraString(extraStringID(e.base.extra(version.Go122)[1]))
panic(fmt.Sprintf("internal error: unexpected event type for Task kind: %s", go122.EventString(e.base.typ)))
return Task{
ID: TaskID(e.base.args[0]),
Parent: parentID,
Type: typ,
// Region returns details about a RegionBegin or RegionEnd event.
// Panics if Kind != EventRegionBegin and Kind != EventRegionEnd.
func (e Event) Region() Region {
if kind := e.Kind(); kind != EventRegionBegin && kind != EventRegionEnd {
panic("Region called on non-Region event")
if e.base.typ != go122.EvUserRegionBegin && e.base.typ != go122.EvUserRegionEnd {
panic(fmt.Sprintf("internal error: unexpected event type for Region kind: %s", go122.EventString(e.base.typ)))
return Region{
Task: TaskID(e.base.args[0]),
Type: e.table.strings.mustGet(stringID(e.base.args[1])),
// Log returns details about a Log event.
// Panics if Kind != EventLog.
func (e Event) Log() Log {
if e.Kind() != EventLog {
panic("Log called on non-Log event")
if e.base.typ != go122.EvUserLog {
panic(fmt.Sprintf("internal error: unexpected event type for Log kind: %s", go122.EventString(e.base.typ)))
return Log{
Task: TaskID(e.base.args[0]),
Category: e.table.strings.mustGet(stringID(e.base.args[1])),
Message: e.table.strings.mustGet(stringID(e.base.args[2])),
// StateTransition returns details about a StateTransition event.
// Panics if Kind != EventStateTransition.
func (e Event) StateTransition() StateTransition {
if e.Kind() != EventStateTransition {
panic("StateTransition called on non-StateTransition event")
var s StateTransition
switch e.base.typ {
case go122.EvProcStart:
s = procStateTransition(ProcID(e.base.args[0]), ProcIdle, ProcRunning)
case go122.EvProcStop:
s = procStateTransition(e.ctx.P, ProcRunning, ProcIdle)
case go122.EvProcSteal:
// N.B. ordering.advance populates e.base.extra.
beforeState := ProcRunning
if go122.ProcStatus(e.base.extra(version.Go122)[0]) == go122.ProcSyscallAbandoned {
// We've lost information because this ProcSteal advanced on a
// SyscallAbandoned state. Treat the P as idle because ProcStatus
// treats SyscallAbandoned as Idle. Otherwise we'll have an invalid
// transition.
beforeState = ProcIdle
s = procStateTransition(ProcID(e.base.args[0]), beforeState, ProcIdle)
case go122.EvProcStatus:
// N.B. ordering.advance populates e.base.extra.
s = procStateTransition(ProcID(e.base.args[0]), ProcState(e.base.extra(version.Go122)[0]), go122ProcStatus2ProcState[e.base.args[1]])
case go122.EvGoCreate, go122.EvGoCreateBlocked:
status := GoRunnable
if e.base.typ == go122.EvGoCreateBlocked {
status = GoWaiting
s = goStateTransition(GoID(e.base.args[0]), GoNotExist, status)
s.Stack = Stack{table: e.table, id: stackID(e.base.args[1])}
case go122.EvGoCreateSyscall:
s = goStateTransition(GoID(e.base.args[0]), GoNotExist, GoSyscall)
case go122.EvGoStart:
s = goStateTransition(GoID(e.base.args[0]), GoRunnable, GoRunning)
case go122.EvGoDestroy:
s = goStateTransition(e.ctx.G, GoRunning, GoNotExist)
s.Stack = e.Stack() // This event references the resource the event happened on.
case go122.EvGoDestroySyscall:
s = goStateTransition(e.ctx.G, GoSyscall, GoNotExist)
case go122.EvGoStop:
s = goStateTransition(e.ctx.G, GoRunning, GoRunnable)
s.Reason = e.table.strings.mustGet(stringID(e.base.args[0]))
s.Stack = e.Stack() // This event references the resource the event happened on.
case go122.EvGoBlock:
s = goStateTransition(e.ctx.G, GoRunning, GoWaiting)
s.Reason = e.table.strings.mustGet(stringID(e.base.args[0]))
s.Stack = e.Stack() // This event references the resource the event happened on.
case go122.EvGoUnblock, go122.EvGoSwitch, go122.EvGoSwitchDestroy:
// N.B. GoSwitch and GoSwitchDestroy both emit additional events, but
// the first thing they both do is unblock the goroutine they name,
// identically to an unblock event (even their arguments match).
s = goStateTransition(GoID(e.base.args[0]), GoWaiting, GoRunnable)
case go122.EvGoSyscallBegin:
s = goStateTransition(e.ctx.G, GoRunning, GoSyscall)
s.Stack = e.Stack() // This event references the resource the event happened on.
case go122.EvGoSyscallEnd:
s = goStateTransition(e.ctx.G, GoSyscall, GoRunning)
s.Stack = e.Stack() // This event references the resource the event happened on.
case go122.EvGoSyscallEndBlocked:
s = goStateTransition(e.ctx.G, GoSyscall, GoRunnable)
s.Stack = e.Stack() // This event references the resource the event happened on.
case go122.EvGoStatus:
// N.B. ordering.advance populates e.base.extra.
s = goStateTransition(GoID(e.base.args[0]), GoState(e.base.extra(version.Go122)[0]), go122GoStatus2GoState[e.base.args[2]])
panic(fmt.Sprintf("internal error: unexpected event type for StateTransition kind: %s", go122.EventString(e.base.typ)))
return s
const evSync = ^event.Type(0)
var go122Type2Kind = [...]EventKind{
go122.EvCPUSample: EventStackSample,
go122.EvProcsChange: EventMetric,
go122.EvProcStart: EventStateTransition,
go122.EvProcStop: EventStateTransition,
go122.EvProcSteal: EventStateTransition,
go122.EvProcStatus: EventStateTransition,
go122.EvGoCreate: EventStateTransition,
go122.EvGoCreateSyscall: EventStateTransition,
go122.EvGoStart: EventStateTransition,
go122.EvGoDestroy: EventStateTransition,
go122.EvGoDestroySyscall: EventStateTransition,
go122.EvGoStop: EventStateTransition,
go122.EvGoBlock: EventStateTransition,
go122.EvGoUnblock: EventStateTransition,
go122.EvGoSyscallBegin: EventStateTransition,
go122.EvGoSyscallEnd: EventStateTransition,
go122.EvGoSyscallEndBlocked: EventStateTransition,
go122.EvGoStatus: EventStateTransition,
go122.EvSTWBegin: EventRangeBegin,
go122.EvSTWEnd: EventRangeEnd,
go122.EvGCActive: EventRangeActive,
go122.EvGCBegin: EventRangeBegin,
go122.EvGCEnd: EventRangeEnd,
go122.EvGCSweepActive: EventRangeActive,
go122.EvGCSweepBegin: EventRangeBegin,
go122.EvGCSweepEnd: EventRangeEnd,
go122.EvGCMarkAssistActive: EventRangeActive,
go122.EvGCMarkAssistBegin: EventRangeBegin,
go122.EvGCMarkAssistEnd: EventRangeEnd,
go122.EvHeapAlloc: EventMetric,
go122.EvHeapGoal: EventMetric,
go122.EvGoLabel: EventLabel,
go122.EvUserTaskBegin: EventTaskBegin,
go122.EvUserTaskEnd: EventTaskEnd,
go122.EvUserRegionBegin: EventRegionBegin,
go122.EvUserRegionEnd: EventRegionEnd,
go122.EvUserLog: EventLog,
go122.EvGoSwitch: EventStateTransition,
go122.EvGoSwitchDestroy: EventStateTransition,
go122.EvGoCreateBlocked: EventStateTransition,
evSync: EventSync,
var go122GoStatus2GoState = [...]GoState{
go122.GoRunnable: GoRunnable,
go122.GoRunning: GoRunning,
go122.GoWaiting: GoWaiting,
go122.GoSyscall: GoSyscall,
var go122ProcStatus2ProcState = [...]ProcState{
go122.ProcRunning: ProcRunning,
go122.ProcIdle: ProcIdle,
go122.ProcSyscall: ProcRunning,
go122.ProcSyscallAbandoned: ProcIdle,
// String returns the event as a human-readable string.
// The format of the string is intended for debugging and is subject to change.
func (e Event) String() string {
var sb strings.Builder
fmt.Fprintf(&sb, "M=%d P=%d G=%d", e.Thread(), e.Proc(), e.Goroutine())
fmt.Fprintf(&sb, " %s Time=%d", e.Kind(), e.Time())
// Kind-specific fields.
switch kind := e.Kind(); kind {
case EventMetric:
m := e.Metric()
fmt.Fprintf(&sb, " Name=%q Value=%s", m.Name, valueAsString(m.Value))
case EventLabel:
l := e.Label()
fmt.Fprintf(&sb, " Label=%q Resource=%s", l.Label, l.Resource)
case EventRangeBegin, EventRangeActive, EventRangeEnd:
r := e.Range()
fmt.Fprintf(&sb, " Name=%q Scope=%s", r.Name, r.Scope)
if kind == EventRangeEnd {
fmt.Fprintf(&sb, " Attributes=[")
for i, attr := range e.RangeAttributes() {
if i != 0 {
fmt.Fprintf(&sb, " ")
fmt.Fprintf(&sb, "%q=%s", attr.Name, valueAsString(attr.Value))
fmt.Fprintf(&sb, "]")
case EventTaskBegin, EventTaskEnd:
t := e.Task()
fmt.Fprintf(&sb, " ID=%d Parent=%d Type=%q", t.ID, t.Parent, t.Type)
case EventRegionBegin, EventRegionEnd:
r := e.Region()
fmt.Fprintf(&sb, " Task=%d Type=%q", r.Task, r.Type)
case EventLog:
l := e.Log()
fmt.Fprintf(&sb, " Task=%d Category=%q Message=%q", l.Task, l.Category, l.Message)
case EventStateTransition:
s := e.StateTransition()
fmt.Fprintf(&sb, " Resource=%s Reason=%q", s.Resource, s.Reason)
switch s.Resource.Kind {
case ResourceGoroutine:
id := s.Resource.Goroutine()
old, new := s.Goroutine()
fmt.Fprintf(&sb, " GoID=%d %s->%s", id, old, new)
case ResourceProc:
id := s.Resource.Proc()
old, new := s.Proc()
fmt.Fprintf(&sb, " ProcID=%d %s->%s", id, old, new)
if s.Stack != NoStack {
fmt.Fprintln(&sb, "TransitionStack=")
s.Stack.Frames(func(f StackFrame) bool {
fmt.Fprintf(&sb, "\t%s @ 0x%x\n", f.Func, f.PC)
fmt.Fprintf(&sb, "\t\t%s:%d\n", f.File, f.Line)
return true
if stk := e.Stack(); stk != NoStack {
fmt.Fprintln(&sb, "Stack=")
stk.Frames(func(f StackFrame) bool {
fmt.Fprintf(&sb, "\t%s @ 0x%x\n", f.Func, f.PC)
fmt.Fprintf(&sb, "\t\t%s:%d\n", f.File, f.Line)
return true
return sb.String()
// validateTableIDs checks to make sure lookups in e.table
// will work.
func (e Event) validateTableIDs() error {
if e.base.typ == evSync {
return nil
spec := go122.Specs()[e.base.typ]
// Check stacks.
for _, i := range spec.StackIDs {
id := stackID(e.base.args[i-1])
_, ok := e.table.stacks.get(id)
if !ok {
return fmt.Errorf("found invalid stack ID %d for event %s", id, spec.Name)
// N.B. Strings referenced by stack frames are validated
// early on, when reading the stacks in to begin with.
// Check strings.
for _, i := range spec.StringIDs {
id := stringID(e.base.args[i-1])
_, ok := e.table.strings.get(id)
if !ok {
return fmt.Errorf("found invalid string ID %d for event %s", id, spec.Name)
return nil
func syncEvent(table *evTable, ts Time) Event {
return Event{
table: table,
ctx: schedCtx{
G: NoGoroutine,
P: NoProc,
M: NoThread,
base: baseEvent{
typ: evSync,
time: ts,