internal/trace: merge event and tracev2 packages

These two packages were historically separate in an attempt to provide a
unified description of trace v1 and trace v2 formats. In practice this
turned out to be pointless, since it made more sense to keep the trace
v1 parser in a self-contained bubble with a converter to v2. Future
trace wire format migrations should probably just follow the same
general strategy, if there's a substantial change. (Minor changes can be
handled more organically.)

Change-Id: Ic765df62065fe53cfae59b505297527c3fa42dfb
Reviewed-on: https://go-review.googlesource.com/c/go/+/645395
Auto-Submit: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>

src/cmd/trace/main.go

@@ -12,7 +12,7 @@ import (
 	"fmt"
 	"internal/trace"
 	"internal/trace/raw"
-	"internal/trace/tracev2/event"
+	"internal/trace/tracev2"
 	"internal/trace/traceviewer"
 	"io"
 	"log"
@@ -372,13 +372,13 @@ func debugEventsFootprint(trc io.Reader) error {
 		return err
 	}
 	type eventStats struct {
-		typ   event.Type
+		typ   tracev2.EventType
 		count int
 		bytes int
 	}
 	var stats [256]eventStats
 	for i := range stats {
-		stats[i].typ = event.Type(i)
+		stats[i].typ = tracev2.EventType(i)
 	}
 	eventsRead := 0
 	for {

src/go/build/deps_test.go

@@ -58,7 +58,7 @@ var depsRules = `
 	  internal/platform,
 	  internal/profilerecord,
 	  internal/syslist,
-	  internal/trace/tracev2/event,
+	  internal/trace/tracev2,
 	  internal/trace/traceviewer/format,
 	  log/internal,
 	  math/bits,
@@ -80,6 +80,7 @@ var depsRules = `
 	internal/goexperiment,
 	internal/goos,
 	internal/profilerecord,
+	internal/trace/tracev2,
 	math/bits,
 	structs
 	< internal/bytealg
@@ -699,16 +700,13 @@ var depsRules = `
 	< crypto/internal/fips140/check/checktest;
 
 	# v2 execution trace parser.
-	internal/trace/tracev2/event
-	< internal/trace/tracev2;
-
 	FMT, io, internal/trace/tracev2
 	< internal/trace/version;
 
 	FMT, encoding/binary, internal/trace/version
 	< internal/trace/raw;
 
-	FMT, internal/trace/tracev2/event, internal/trace/version, io, sort, encoding/binary
+	FMT, internal/trace/version, io, sort, encoding/binary
 	< internal/trace/internal/tracev1;
 
 	FMT, encoding/binary, internal/trace/version, internal/trace/internal/tracev1, container/heap, math/rand

src/internal/trace/base.go

@@ -13,7 +13,6 @@ import (
 	"strings"
 
 	"internal/trace/tracev2"
-	"internal/trace/tracev2/event"
 	"internal/trace/version"
 )
 
@@ -28,7 +27,7 @@ type timedEventArgs [maxArgs - 1]uint64
 // baseEvent is the basic unprocessed event. This serves as a common
 // fundamental data structure across.
 type baseEvent struct {
-	typ  event.Type
+	typ  tracev2.EventType
 	time Time
 	args timedEventArgs
 }
@@ -59,7 +58,7 @@ type evTable struct {
 	nextExtra      extraStringID
 
 	// expBatches contains extra unparsed data relevant to a specific experiment.
-	expBatches map[event.Experiment][]ExperimentalBatch
+	expBatches map[tracev2.Experiment][]ExperimentalBatch
 }
 
 // addExtraString adds an extra string to the evTable and returns

src/internal/trace/batch.go

@@ -11,7 +11,6 @@ import (
 	"io"
 
 	"internal/trace/tracev2"
-	"internal/trace/tracev2/event"
 )
 
 // timestamp is an unprocessed timestamp.
@@ -23,23 +22,23 @@ type batch struct {
 	m    ThreadID
 	time timestamp
 	data []byte
-	exp  event.Experiment
+	exp  tracev2.Experiment
 }
 
 func (b *batch) isStringsBatch() bool {
-	return b.exp == event.NoExperiment && len(b.data) > 0 && event.Type(b.data[0]) == tracev2.EvStrings
+	return b.exp == tracev2.NoExperiment && len(b.data) > 0 && tracev2.EventType(b.data[0]) == tracev2.EvStrings
 }
 
 func (b *batch) isStacksBatch() bool {
-	return b.exp == event.NoExperiment && len(b.data) > 0 && event.Type(b.data[0]) == tracev2.EvStacks
+	return b.exp == tracev2.NoExperiment && len(b.data) > 0 && tracev2.EventType(b.data[0]) == tracev2.EvStacks
 }
 
 func (b *batch) isCPUSamplesBatch() bool {
-	return b.exp == event.NoExperiment && len(b.data) > 0 && event.Type(b.data[0]) == tracev2.EvCPUSamples
+	return b.exp == tracev2.NoExperiment && len(b.data) > 0 && tracev2.EventType(b.data[0]) == tracev2.EvCPUSamples
 }
 
 func (b *batch) isFreqBatch() bool {
-	return b.exp == event.NoExperiment && len(b.data) > 0 && event.Type(b.data[0]) == tracev2.EvFrequency
+	return b.exp == tracev2.NoExperiment && len(b.data) > 0 && tracev2.EventType(b.data[0]) == tracev2.EvFrequency
 }
 
 // readBatch reads the next full batch from r.
@@ -52,18 +51,18 @@ func readBatch(r interface {
 	if err != nil {
 		return batch{}, 0, err
 	}
-	if typ := event.Type(b); typ != tracev2.EvEventBatch && typ != tracev2.EvExperimentalBatch {
+	if typ := tracev2.EventType(b); typ != tracev2.EvEventBatch && typ != tracev2.EvExperimentalBatch {
 		return batch{}, 0, fmt.Errorf("expected batch event, got event %d", typ)
 	}
 
 	// Read the experiment of we have one.
-	exp := event.NoExperiment
-	if event.Type(b) == tracev2.EvExperimentalBatch {
+	exp := tracev2.NoExperiment
+	if tracev2.EventType(b) == tracev2.EvExperimentalBatch {
 		e, err := r.ReadByte()
 		if err != nil {
 			return batch{}, 0, err
 		}
-		exp = event.Experiment(e)
+		exp = tracev2.Experiment(e)
 	}
 
 	// Read the batch header: gen (generation), thread (M) ID, base timestamp

src/internal/trace/batchcursor.go

@@ -10,7 +10,6 @@ import (
 	"fmt"
 
 	"internal/trace/tracev2"
-	"internal/trace/tracev2/event"
 )
 
 type batchCursor struct {
@@ -66,7 +65,7 @@ func (b *batchCursor) compare(a *batchCursor) int {
 // be the case for every event in a plain EventBatch.
 func readTimedBaseEvent(b []byte, e *baseEvent) (int, timestamp, error) {
 	// Get the event type.
-	typ := event.Type(b[0])
+	typ := tracev2.EventType(b[0])
 	specs := tracev2.Specs()
 	if int(typ) >= len(specs) {
 		return 0, 0, fmt.Errorf("found invalid event type: %v", typ)

src/internal/trace/event.go

@@ -12,7 +12,6 @@ import (
 	"time"
 
 	"internal/trace/tracev2"
-	"internal/trace/tracev2/event"
 	"internal/trace/version"
 )
 
@@ -693,7 +692,7 @@ func (e Event) Experimental() ExperimentalEvent {
 	}
 }
 
-const evSync = ^event.Type(0)
+const evSync = ^tracev2.EventType(0)
 
 var tracev2Type2Kind = [...]EventKind{
 	tracev2.EvCPUSample:           EventStackSample,

src/internal/trace/generation.go

@@ -15,7 +15,6 @@ import (
 	"strings"
 
 	"internal/trace/tracev2"
-	"internal/trace/tracev2/event"
 )
 
 // generation contains all the trace data for a single
@@ -166,9 +165,9 @@ func processBatch(g *generation, b batch) error {
 			return fmt.Errorf("found multiple frequency events")
 		}
 		g.freq = freq
-	case b.exp != event.NoExperiment:
+	case b.exp != tracev2.NoExperiment:
 		if g.expBatches == nil {
-			g.expBatches = make(map[event.Experiment][]ExperimentalBatch)
+			g.expBatches = make(map[tracev2.Experiment][]ExperimentalBatch)
 		}
 		if err := addExperimentalBatch(g.expBatches, b); err != nil {
 			return err
@@ -222,7 +221,7 @@ func addStrings(stringTable *dataTable[stringID, string], b batch) error {
 	}
 	r := bytes.NewReader(b.data)
 	hdr, err := r.ReadByte() // Consume the EvStrings byte.
-	if err != nil || event.Type(hdr) != tracev2.EvStrings {
+	if err != nil || tracev2.EventType(hdr) != tracev2.EvStrings {
 		return fmt.Errorf("missing strings batch header")
 	}
 
@@ -233,7 +232,7 @@ func addStrings(stringTable *dataTable[stringID, string], b batch) error {
 		if err != nil {
 			return err
 		}
-		if event.Type(ev) != tracev2.EvString {
+		if tracev2.EventType(ev) != tracev2.EvString {
 			return fmt.Errorf("expected string event, got %d", ev)
 		}
 
@@ -248,8 +247,8 @@ func addStrings(stringTable *dataTable[stringID, string], b batch) error {
 		if err != nil {
 			return err
 		}
-		if len > tracev2.MaxStringSize {
-			return fmt.Errorf("invalid string size %d, maximum is %d", len, tracev2.MaxStringSize)
+		if len > tracev2.MaxEventTrailerDataSize {
+			return fmt.Errorf("invalid string size %d, maximum is %d", len, tracev2.MaxEventTrailerDataSize)
 		}
 
 		// Copy out the string.
@@ -280,7 +279,7 @@ func addStacks(stackTable *dataTable[stackID, stack], pcs map[uint64]frame, b ba
 	}
 	r := bytes.NewReader(b.data)
 	hdr, err := r.ReadByte() // Consume the EvStacks byte.
-	if err != nil || event.Type(hdr) != tracev2.EvStacks {
+	if err != nil || tracev2.EventType(hdr) != tracev2.EvStacks {
 		return fmt.Errorf("missing stacks batch header")
 	}
 
@@ -290,7 +289,7 @@ func addStacks(stackTable *dataTable[stackID, stack], pcs map[uint64]frame, b ba
 		if err != nil {
 			return err
 		}
-		if event.Type(ev) != tracev2.EvStack {
+		if tracev2.EventType(ev) != tracev2.EvStack {
 			return fmt.Errorf("expected stack event, got %d", ev)
 		}
 
@@ -358,7 +357,7 @@ func addCPUSamples(samples []cpuSample, b batch) ([]cpuSample, error) {
 	}
 	r := bytes.NewReader(b.data)
 	hdr, err := r.ReadByte() // Consume the EvCPUSamples byte.
-	if err != nil || event.Type(hdr) != tracev2.EvCPUSamples {
+	if err != nil || tracev2.EventType(hdr) != tracev2.EvCPUSamples {
 		return nil, fmt.Errorf("missing CPU samples batch header")
 	}
 
@@ -368,7 +367,7 @@ func addCPUSamples(samples []cpuSample, b batch) ([]cpuSample, error) {
 		if err != nil {
 			return nil, err
 		}
-		if event.Type(ev) != tracev2.EvCPUSample {
+		if tracev2.EventType(ev) != tracev2.EvCPUSample {
 			return nil, fmt.Errorf("expected CPU sample event, got %d", ev)
 		}
 
@@ -441,8 +440,8 @@ func parseFreq(b batch) (frequency, error) {
 
 // addExperimentalBatch takes an experimental batch and adds it to the list of experimental
 // batches for the experiment its a part of.
-func addExperimentalBatch(expBatches map[event.Experiment][]ExperimentalBatch, b batch) error {
-	if b.exp == event.NoExperiment {
+func addExperimentalBatch(expBatches map[tracev2.Experiment][]ExperimentalBatch, b batch) error {
+	if b.exp == tracev2.NoExperiment {
 		return fmt.Errorf("internal error: addExperimentalBatch called on non-experimental batch")
 	}
 	expBatches[b.exp] = append(expBatches[b.exp], ExperimentalBatch{

src/internal/trace/internal/testgen/trace.go

@@ -15,7 +15,6 @@ import (
 	"internal/trace"
 	"internal/trace/raw"
 	"internal/trace/tracev2"
-	"internal/trace/tracev2/event"
 	"internal/trace/version"
 	"internal/txtar"
 )
@@ -51,8 +50,8 @@ func Main(ver version.Version, f func(*Trace)) {
 type Trace struct {
 	// Trace data state.
 	ver             version.Version
-	names           map[string]event.Type
-	specs           []event.Spec
+	names           map[string]tracev2.EventType
+	specs           []tracev2.EventSpec
 	events          []raw.Event
 	gens            []*Generation
 	validTimestamps bool
@@ -65,7 +64,7 @@ type Trace struct {
 // NewTrace creates a new trace.
 func NewTrace(ver version.Version) *Trace {
 	return &Trace{
-		names:           event.Names(ver.Specs()),
+		names:           tracev2.EventNames(ver.Specs()),
 		specs:           ver.Specs(),
 		validTimestamps: true,
 	}
@@ -86,7 +85,7 @@ func (t *Trace) ExpectSuccess() {
 // RawEvent emits an event into the trace. name must correspond to one
 // of the names in Specs() result for the version that was passed to
 // this trace.
-func (t *Trace) RawEvent(typ event.Type, data []byte, args ...uint64) {
+func (t *Trace) RawEvent(typ tracev2.EventType, data []byte, args ...uint64) {
 	t.events = append(t.events, t.createEvent(typ, data, args...))
 }
 
@@ -146,7 +145,7 @@ func (t *Trace) Generate() []byte {
 	})
 }
 
-func (t *Trace) createEvent(ev event.Type, data []byte, args ...uint64) raw.Event {
+func (t *Trace) createEvent(ev tracev2.EventType, data []byte, args ...uint64) raw.Event {
 	spec := t.specs[ev]
 	if ev != tracev2.EvStack {
 		if arity := len(spec.Args); len(args) != arity {
@@ -362,7 +361,7 @@ func (b *Batch) uintArgFor(arg any, argSpec string) uint64 {
 // RawEvent emits an event into a batch. name must correspond to one
 // of the names in Specs() result for the version that was passed to
 // this trace.
-func (b *Batch) RawEvent(typ event.Type, data []byte, args ...uint64) {
+func (b *Batch) RawEvent(typ tracev2.EventType, data []byte, args ...uint64) {
 	ev := b.gen.trace.createEvent(typ, data, args...)
 
 	// Compute the size of the event and add it to the batch.