runtime, cmd/trace: remove code paths that include v1 tracer

This change makes the new execution tracer described in #60773, the
default tracer. This change attempts to make the smallest amount of
changes for a single CL.

Updates #66703
For #60773

Change-Id: I3742f3419c54f07d7c020ae5e1c18d29d8bcae6d
Reviewed-on: https://go-review.googlesource.com/c/go/+/576256
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: cagedmantis

src/cmd/trace/annotations_test.go

@@ -7,24 +7,10 @@
 package main
 
 import (
-	"bytes"
-	"context"
-	"flag"
-	"fmt"
-	"internal/goexperiment"
-	traceparser "internal/trace"
-	"os"
-	"reflect"
-	"runtime/debug"
-	"runtime/trace"
-	"sort"
-	"sync"
 	"testing"
 	"time"
 )
 
-var saveTraces = flag.Bool("savetraces", false, "save traces collected by tests")
-
 func TestOverlappingDuration(t *testing.T) {
 	cases := []struct {
 		start0, end0, start1, end1 int64
@@ -51,346 +37,3 @@ func TestOverlappingDuration(t *testing.T) {
 		}
 	}
 }
-
-// prog0 starts three goroutines.
-//
-//	goroutine 1: taskless region
-//	goroutine 2: starts task0, do work in task0.region0, starts task1 which ends immediately.
-//	goroutine 3: do work in task0.region1 and task0.region2, ends task0
-func prog0() {
-	ctx := context.Background()
-
-	var wg sync.WaitGroup
-
-	wg.Add(1)
-	go func() { // goroutine 1
-		defer wg.Done()
-		trace.WithRegion(ctx, "taskless.region", func() {
-			trace.Log(ctx, "key0", "val0")
-		})
-	}()
-
-	wg.Add(1)
-	go func() { // goroutine 2
-		defer wg.Done()
-		ctx, task := trace.NewTask(ctx, "task0")
-		trace.WithRegion(ctx, "task0.region0", func() {
-			wg.Add(1)
-			go func() { // goroutine 3
-				defer wg.Done()
-				defer task.End()
-				trace.WithRegion(ctx, "task0.region1", func() {
-					trace.WithRegion(ctx, "task0.region2", func() {
-						trace.Log(ctx, "key2", "val2")
-					})
-					trace.Log(ctx, "key1", "val1")
-				})
-			}()
-		})
-		ctx2, task2 := trace.NewTask(ctx, "task1")
-		trace.Log(ctx2, "key3", "val3")
-		task2.End()
-	}()
-	wg.Wait()
-}
-
-func TestAnalyzeAnnotations(t *testing.T) {
-	// TODO: classify taskless regions
-
-	// Run prog0 and capture the execution trace.
-	if err := traceProgram(t, prog0, "TestAnalyzeAnnotations"); err != nil {
-		t.Fatalf("failed to trace the program: %v", err)
-	}
-
-	res, err := analyzeAnnotations()
-	if err != nil {
-		t.Fatalf("failed to analyzeAnnotations: %v", err)
-	}
-
-	// For prog0, we expect
-	//   - task with name = "task0", with three regions.
-	//   - task with name = "task1", with no region.
-	wantTasks := map[string]struct {
-		complete   bool
-		goroutines int
-		regions    []string
-	}{
-		"task0": {
-			complete:   true,
-			goroutines: 2,
-			regions:    []string{"task0.region0", "", "task0.region1", "task0.region2"},
-		},
-		"task1": {
-			complete:   true,
-			goroutines: 1,
-		},
-	}
-
-	for _, task := range res.tasks {
-		want, ok := wantTasks[task.name]
-		if !ok {
-			t.Errorf("unexpected task: %s", task)
-			continue
-		}
-		if task.complete() != want.complete || len(task.goroutines) != want.goroutines || !reflect.DeepEqual(regionNames(task), want.regions) {
-			t.Errorf("got task %v; want %+v", task, want)
-		}
-
-		delete(wantTasks, task.name)
-	}
-	if len(wantTasks) > 0 {
-		t.Errorf("no more tasks; want %+v", wantTasks)
-	}
-
-	wantRegions := []string{
-		"", // an auto-created region for the goroutine 3
-		"taskless.region",
-		"task0.region0",
-		"task0.region1",
-		"task0.region2",
-	}
-	var gotRegions []string
-	for regionID := range res.regions {
-		gotRegions = append(gotRegions, regionID.Type)
-	}
-
-	sort.Strings(wantRegions)
-	sort.Strings(gotRegions)
-	if !reflect.DeepEqual(gotRegions, wantRegions) {
-		t.Errorf("got regions %q, want regions %q", gotRegions, wantRegions)
-	}
-}
-
-// prog1 creates a task hierarchy consisting of three tasks.
-func prog1() {
-	ctx := context.Background()
-	ctx1, task1 := trace.NewTask(ctx, "task1")
-	defer task1.End()
-	trace.WithRegion(ctx1, "task1.region", func() {
-		ctx2, task2 := trace.NewTask(ctx1, "task2")
-		defer task2.End()
-		trace.WithRegion(ctx2, "task2.region", func() {
-			ctx3, task3 := trace.NewTask(ctx2, "task3")
-			defer task3.End()
-			trace.WithRegion(ctx3, "task3.region", func() {
-			})
-		})
-	})
-}
-
-func TestAnalyzeAnnotationTaskTree(t *testing.T) {
-	// Run prog1 and capture the execution trace.
-	if err := traceProgram(t, prog1, "TestAnalyzeAnnotationTaskTree"); err != nil {
-		t.Fatalf("failed to trace the program: %v", err)
-	}
-
-	res, err := analyzeAnnotations()
-	if err != nil {
-		t.Fatalf("failed to analyzeAnnotations: %v", err)
-	}
-	tasks := res.tasks
-
-	// For prog0, we expect
-	//   - task with name = "", with taskless.region in regions.
-	//   - task with name = "task0", with three regions.
-	wantTasks := map[string]struct {
-		parent   string
-		children []string
-		regions  []string
-	}{
-		"task1": {
-			parent:   "",
-			children: []string{"task2"},
-			regions:  []string{"task1.region"},
-		},
-		"task2": {
-			parent:   "task1",
-			children: []string{"task3"},
-			regions:  []string{"task2.region"},
-		},
-		"task3": {
-			parent:   "task2",
-			children: nil,
-			regions:  []string{"task3.region"},
-		},
-	}
-
-	for _, task := range tasks {
-		want, ok := wantTasks[task.name]
-		if !ok {
-			t.Errorf("unexpected task: %s", task)
-			continue
-		}
-		delete(wantTasks, task.name)
-
-		if parentName(task) != want.parent ||
-			!reflect.DeepEqual(childrenNames(task), want.children) ||
-			!reflect.DeepEqual(regionNames(task), want.regions) {
-			t.Errorf("got %v; want %+v", task, want)
-		}
-	}
-
-	if len(wantTasks) > 0 {
-		t.Errorf("no more tasks; want %+v", wantTasks)
-	}
-}
-
-// prog2 starts two tasks; "taskWithGC" that overlaps with GC
-// and "taskWithoutGC" that doesn't. In order to run this reliably,
-// the caller needs to set up to prevent GC from running automatically.
-// prog2 returns the upper-bound gc time that overlaps with the first task.
-func prog2() (gcTime time.Duration) {
-	ch := make(chan bool)
-	ctx1, task := trace.NewTask(context.Background(), "taskWithGC")
-	trace.WithRegion(ctx1, "taskWithGC.region1", func() {
-		go func() {
-			defer trace.StartRegion(ctx1, "taskWithGC.region2").End()
-			<-ch
-		}()
-		s := time.Now()
-		debug.FreeOSMemory() // task1 affected by gc
-		gcTime = time.Since(s)
-		close(ch)
-	})
-	task.End()
-
-	ctx2, task2 := trace.NewTask(context.Background(), "taskWithoutGC")
-	trace.WithRegion(ctx2, "taskWithoutGC.region1", func() {
-		// do nothing.
-	})
-	task2.End()
-	return gcTime
-}
-
-func TestAnalyzeAnnotationGC(t *testing.T) {
-	err := traceProgram(t, func() {
-		oldGC := debug.SetGCPercent(10000) // gc, and effectively disable GC
-		defer debug.SetGCPercent(oldGC)
-		prog2()
-	}, "TestAnalyzeAnnotationGC")
-	if err != nil {
-		t.Fatalf("failed to trace the program: %v", err)
-	}
-
-	res, err := analyzeAnnotations()
-	if err != nil {
-		t.Fatalf("failed to analyzeAnnotations: %v", err)
-	}
-
-	// Check collected GC Start events are all sorted and non-overlapping.
-	lastTS := int64(0)
-	for i, ev := range res.gcEvents {
-		if ev.Type != traceparser.EvGCStart {
-			t.Errorf("unwanted event in gcEvents: %v", ev)
-		}
-		if i > 0 && lastTS > ev.Ts {
-			t.Errorf("overlapping GC events:\n%d: %v\n%d: %v", i-1, res.gcEvents[i-1], i, res.gcEvents[i])
-		}
-		if ev.Link != nil {
-			lastTS = ev.Link.Ts
-		}
-	}
-
-	// Check whether only taskWithGC reports overlapping duration.
-	for _, task := range res.tasks {
-		got := task.overlappingGCDuration(res.gcEvents)
-		switch task.name {
-		case "taskWithoutGC":
-			if got != 0 {
-				t.Errorf("%s reported %v as overlapping GC time; want 0: %v", task.name, got, task)
-			}
-		case "taskWithGC":
-			upperBound := task.duration()
-			// TODO(hyangah): a tighter upper bound is gcTime, but
-			// use of it will make the test flaky due to the issue
-			// described in golang.org/issue/16755. Tighten the upper
-			// bound when the issue with the timestamp computed
-			// based on clockticks is resolved.
-			if got <= 0 || got > upperBound {
-				t.Errorf("%s reported %v as overlapping GC time; want (0, %v):\n%v", task.name, got, upperBound, task)
-				buf := new(bytes.Buffer)
-				fmt.Fprintln(buf, "GC Events")
-				for _, ev := range res.gcEvents {
-					fmt.Fprintf(buf, " %s -> %s\n", ev, ev.Link)
-				}
-				fmt.Fprintln(buf, "Events in Task")
-				for i, ev := range task.events {
-					fmt.Fprintf(buf, " %d: %s\n", i, ev)
-				}
-
-				t.Logf("\n%s", buf)
-			}
-		}
-	}
-}
-
-// traceProgram runs the provided function while tracing is enabled,
-// parses the captured trace, and sets the global trace loader to
-// point to the parsed trace.
-//
-// If savetraces flag is set, the captured trace will be saved in the named file.
-func traceProgram(t *testing.T, f func(), name string) error {
-	t.Helper()
-	if goexperiment.ExecTracer2 {
-		t.Skip("skipping because test programs are covered elsewhere for the new tracer")
-	}
-	buf := new(bytes.Buffer)
-	if err := trace.Start(buf); err != nil {
-		return err
-	}
-	f()
-	trace.Stop()
-
-	saveTrace(buf, name)
-	res, err := traceparser.Parse(buf, name+".faketrace")
-	if err == traceparser.ErrTimeOrder {
-		t.Skipf("skipping due to golang.org/issue/16755: %v", err)
-	} else if err != nil {
-		return err
-	}
-
-	swapLoaderData(res, err)
-	return nil
-}
-
-func regionNames(task *taskDesc) (ret []string) {
-	for _, s := range task.regions {
-		ret = append(ret, s.Name)
-	}
-	return ret
-}
-
-func parentName(task *taskDesc) string {
-	if task.parent != nil {
-		return task.parent.name
-	}
-	return ""
-}
-
-func childrenNames(task *taskDesc) (ret []string) {
-	for _, s := range task.children {
-		ret = append(ret, s.name)
-	}
-	return ret
-}
-
-func swapLoaderData(res traceparser.ParseResult, err error) {
-	// swap loader's data.
-	parseTrace() // fool loader.once.
-
-	loader.res = res
-	loader.err = err
-
-	analyzeGoroutines(nil) // fool gsInit once.
-	gs = traceparser.GoroutineStats(res.Events)
-
-}
-
-func saveTrace(buf *bytes.Buffer, name string) {
-	if !*saveTraces {
-		return
-	}
-	if err := os.WriteFile(name+".trace", buf.Bytes(), 0600); err != nil {
-		panic(fmt.Errorf("failed to write trace file: %v", err))
-	}
-}