mirror of https://go.googlesource.com/go
210 lines
9.2 KiB
Go
210 lines
9.2 KiB
Go
// Copyright 2023 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Trace event writing API for trace2runtime.go.
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package runtime
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import (
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"internal/abi"
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"runtime/internal/sys"
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)
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// Event types in the trace, args are given in square brackets.
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//
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// Naming scheme:
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// - Time range event pairs have suffixes "Begin" and "End".
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// - "Start", "Stop", "Create", "Destroy", "Block", "Unblock"
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// are suffixes reserved for scheduling resources.
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//
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// NOTE: If you add an event type, make sure you also update all
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// tables in this file!
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type traceEv uint8
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const (
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traceEvNone traceEv = iota // unused
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// Structural events.
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traceEvEventBatch // start of per-M batch of events [generation, M ID, timestamp, batch length]
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traceEvStacks // start of a section of the stack table [...traceEvStack]
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traceEvStack // stack table entry [ID, ...{PC, func string ID, file string ID, line #}]
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traceEvStrings // start of a section of the string dictionary [...traceEvString]
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traceEvString // string dictionary entry [ID, length, string]
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traceEvCPUSamples // start of a section of CPU samples [...traceEvCPUSample]
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traceEvCPUSample // CPU profiling sample [timestamp, M ID, P ID, goroutine ID, stack ID]
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traceEvFrequency // timestamp units per sec [freq]
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// Procs.
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traceEvProcsChange // current value of GOMAXPROCS [timestamp, GOMAXPROCS, stack ID]
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traceEvProcStart // start of P [timestamp, P ID, P seq]
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traceEvProcStop // stop of P [timestamp]
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traceEvProcSteal // P was stolen [timestamp, P ID, P seq, M ID]
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traceEvProcStatus // P status at the start of a generation [timestamp, P ID, status]
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// Goroutines.
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traceEvGoCreate // goroutine creation [timestamp, new goroutine ID, new stack ID, stack ID]
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traceEvGoCreateSyscall // goroutine appears in syscall (cgo callback) [timestamp, new goroutine ID]
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traceEvGoStart // goroutine starts running [timestamp, goroutine ID, goroutine seq]
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traceEvGoDestroy // goroutine ends [timestamp]
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traceEvGoDestroySyscall // goroutine ends in syscall (cgo callback) [timestamp]
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traceEvGoStop // goroutine yields its time, but is runnable [timestamp, reason, stack ID]
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traceEvGoBlock // goroutine blocks [timestamp, reason, stack ID]
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traceEvGoUnblock // goroutine is unblocked [timestamp, goroutine ID, goroutine seq, stack ID]
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traceEvGoSyscallBegin // syscall enter [timestamp, P seq, stack ID]
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traceEvGoSyscallEnd // syscall exit [timestamp]
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traceEvGoSyscallEndBlocked // syscall exit and it blocked at some point [timestamp]
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traceEvGoStatus // goroutine status at the start of a generation [timestamp, goroutine ID, M ID, status]
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// STW.
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traceEvSTWBegin // STW start [timestamp, kind]
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traceEvSTWEnd // STW done [timestamp]
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// GC events.
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traceEvGCActive // GC active [timestamp, seq]
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traceEvGCBegin // GC start [timestamp, seq, stack ID]
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traceEvGCEnd // GC done [timestamp, seq]
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traceEvGCSweepActive // GC sweep active [timestamp, P ID]
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traceEvGCSweepBegin // GC sweep start [timestamp, stack ID]
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traceEvGCSweepEnd // GC sweep done [timestamp, swept bytes, reclaimed bytes]
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traceEvGCMarkAssistActive // GC mark assist active [timestamp, goroutine ID]
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traceEvGCMarkAssistBegin // GC mark assist start [timestamp, stack ID]
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traceEvGCMarkAssistEnd // GC mark assist done [timestamp]
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traceEvHeapAlloc // gcController.heapLive change [timestamp, heap alloc in bytes]
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traceEvHeapGoal // gcController.heapGoal() change [timestamp, heap goal in bytes]
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// Annotations.
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traceEvGoLabel // apply string label to current running goroutine [timestamp, label string ID]
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traceEvUserTaskBegin // trace.NewTask [timestamp, internal task ID, internal parent task ID, name string ID, stack ID]
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traceEvUserTaskEnd // end of a task [timestamp, internal task ID, stack ID]
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traceEvUserRegionBegin // trace.{Start,With}Region [timestamp, internal task ID, name string ID, stack ID]
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traceEvUserRegionEnd // trace.{End,With}Region [timestamp, internal task ID, name string ID, stack ID]
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traceEvUserLog // trace.Log [timestamp, internal task ID, key string ID, stack, value string ID]
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// Coroutines.
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traceEvGoSwitch // goroutine switch (coroswitch) [timestamp, goroutine ID, goroutine seq]
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traceEvGoSwitchDestroy // goroutine switch and destroy [timestamp, goroutine ID, goroutine seq]
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traceEvGoCreateBlocked // goroutine creation (starts blocked) [timestamp, new goroutine ID, new stack ID, stack ID]
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// GoStatus with stack.
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traceEvGoStatusStack // goroutine status at the start of a generation, with a stack [timestamp, goroutine ID, M ID, status, stack ID]
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// Batch event for an experimental batch with a custom format.
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traceEvExperimentalBatch // start of extra data [experiment ID, generation, M ID, timestamp, batch length, batch data...]
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)
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// traceArg is a simple wrapper type to help ensure that arguments passed
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// to traces are well-formed.
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type traceArg uint64
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// traceEventWriter is the high-level API for writing trace events.
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//
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// See the comment on traceWriter about style for more details as to why
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// this type and its methods are structured the way they are.
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type traceEventWriter struct {
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w traceWriter
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}
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// eventWriter creates a new traceEventWriter. It is the main entrypoint for writing trace events.
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//
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// Before creating the event writer, this method will emit a status for the current goroutine
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// or proc if it exists, and if it hasn't had its status emitted yet. goStatus and procStatus indicate
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// what the status of goroutine or P should be immediately *before* the events that are about to
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// be written using the eventWriter (if they exist). No status will be written if there's no active
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// goroutine or P.
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//
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// Callers can elect to pass a constant value here if the status is clear (e.g. a goroutine must have
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// been Runnable before a GoStart). Otherwise, callers can query the status of either the goroutine
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// or P and pass the appropriate status.
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//
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// In this case, the default status should be traceGoBad or traceProcBad to help identify bugs sooner.
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func (tl traceLocker) eventWriter(goStatus traceGoStatus, procStatus traceProcStatus) traceEventWriter {
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w := tl.writer()
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if pp := tl.mp.p.ptr(); pp != nil && !pp.trace.statusWasTraced(tl.gen) && pp.trace.acquireStatus(tl.gen) {
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w = w.writeProcStatus(uint64(pp.id), procStatus, pp.trace.inSweep)
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}
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if gp := tl.mp.curg; gp != nil && !gp.trace.statusWasTraced(tl.gen) && gp.trace.acquireStatus(tl.gen) {
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w = w.writeGoStatus(uint64(gp.goid), int64(tl.mp.procid), goStatus, gp.inMarkAssist, 0 /* no stack */)
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}
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return traceEventWriter{w}
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}
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// commit writes out a trace event and calls end. It's a helper to make the
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// common case of writing out a single event less error-prone.
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func (e traceEventWriter) commit(ev traceEv, args ...traceArg) {
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e = e.write(ev, args...)
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e.end()
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}
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// write writes an event into the trace.
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func (e traceEventWriter) write(ev traceEv, args ...traceArg) traceEventWriter {
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e.w = e.w.event(ev, args...)
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return e
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}
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// end finishes writing to the trace. The traceEventWriter must not be used after this call.
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func (e traceEventWriter) end() {
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e.w.end()
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}
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// traceEventWrite is the part of traceEvent that actually writes the event.
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func (w traceWriter) event(ev traceEv, args ...traceArg) traceWriter {
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// Make sure we have room.
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w, _ = w.ensure(1 + (len(args)+1)*traceBytesPerNumber)
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// Compute the timestamp diff that we'll put in the trace.
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ts := traceClockNow()
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if ts <= w.traceBuf.lastTime {
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ts = w.traceBuf.lastTime + 1
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}
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tsDiff := uint64(ts - w.traceBuf.lastTime)
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w.traceBuf.lastTime = ts
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// Write out event.
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w.byte(byte(ev))
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w.varint(tsDiff)
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for _, arg := range args {
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w.varint(uint64(arg))
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}
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return w
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}
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// stack takes a stack trace skipping the provided number of frames.
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// It then returns a traceArg representing that stack which may be
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// passed to write.
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func (tl traceLocker) stack(skip int) traceArg {
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return traceArg(traceStack(skip, nil, tl.gen))
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}
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// startPC takes a start PC for a goroutine and produces a unique
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// stack ID for it.
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//
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// It then returns a traceArg representing that stack which may be
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// passed to write.
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func (tl traceLocker) startPC(pc uintptr) traceArg {
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// +PCQuantum because makeTraceFrame expects return PCs and subtracts PCQuantum.
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return traceArg(trace.stackTab[tl.gen%2].put([]uintptr{
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logicalStackSentinel,
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startPCForTrace(pc) + sys.PCQuantum,
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}))
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}
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// string returns a traceArg representing s which may be passed to write.
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// The string is assumed to be relatively short and popular, so it may be
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// stored for a while in the string dictionary.
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func (tl traceLocker) string(s string) traceArg {
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return traceArg(trace.stringTab[tl.gen%2].put(tl.gen, s))
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}
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// uniqueString returns a traceArg representing s which may be passed to write.
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// The string is assumed to be unique or long, so it will be written out to
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// the trace eagerly.
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func (tl traceLocker) uniqueString(s string) traceArg {
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return traceArg(trace.stringTab[tl.gen%2].emit(tl.gen, s))
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}
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// rtype returns a traceArg representing typ which may be passed to write.
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func (tl traceLocker) rtype(typ *abi.Type) traceArg {
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return traceArg(trace.typeTab[tl.gen%2].put(typ))
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}
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