cmd/trace,internal/trace,runtime: refactor to access frames via range over func

Change-Id: Id0be0eb35ae8560bd5338ec296a086aaf4617db0
Reviewed-on: https://go-review.googlesource.com/c/go/+/608856
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

4 files changed, 19 insertions, 23 deletions

diff --git a/src/cmd/trace/gstate.go b/src/cmd/trace/gstate.go
index 76c58073b3..ea501ef57d 100644
--- a/src/cmd/trace/gstate.go
+++ b/src/cmd/trace/gstate.go
@@ -362,11 +362,9 @@ func (gs *gState[R]) rangeEnd(ts trace.Time, name string, stack trace.Stack, ctx
 	delete(gs.activeRanges, name)
 }
 
-func lastFunc(s trace.Stack) string {
-	var last trace.StackFrame
-	s.Frames()(func(f trace.StackFrame) bool {
-		last = f
-		return true
-	})
-	return last.Func
+func lastFunc(s trace.Stack) (fn string) {
+	for frame := range s.Frames() {
+		fn = frame.Func
+	}
+	return
 }
diff --git a/src/cmd/trace/pprof.go b/src/cmd/trace/pprof.go
index 856b97b75f..d27dfa7aa3 100644
--- a/src/cmd/trace/pprof.go
+++ b/src/cmd/trace/pprof.go
@@ -306,19 +306,19 @@ func (m *stackMap) profile() []traceviewer.ProfileRecord {
 	prof := make([]traceviewer.ProfileRecord, 0, len(m.stacks))
 	for stack, record := range m.stacks {
 		rec := *record
-		i := 0
-		stack.Frames()(func(frame trace.StackFrame) bool {
+		for i, frame := range slices.Collect(stack.Frames()) {
 			rec.Stack = append(rec.Stack, &trace.Frame{
 				PC:   frame.PC,
 				Fn:   frame.Func,
 				File: frame.File,
 				Line: int(frame.Line),
 			})
-			i++
 			// Cut this off at pprofMaxStack because that's as far
 			// as our deduplication goes.
-			return i < pprofMaxStack
-		})
+			if i >= pprofMaxStack {
+				break
+			}
+		}
 		prof = append(prof, rec)
 	}
 	return prof
@@ -326,10 +326,10 @@ func (m *stackMap) profile() []traceviewer.ProfileRecord {
 
 // pcsForStack extracts the first pprofMaxStack PCs from stack into pcs.
 func pcsForStack(stack trace.Stack, pcs *[pprofMaxStack]uint64) {
-	i := 0
-	stack.Frames()(func(frame trace.StackFrame) bool {
+	for i, frame := range slices.Collect(stack.Frames()) {
 		pcs[i] = frame.PC
-		i++
-		return i < len(pcs)
-	})
+		if i >= len(pcs) {
+			break
+		}
+	}
 }
diff --git a/src/cmd/trace/regions.go b/src/cmd/trace/regions.go
index cae38355a5..4073b6b07d 100644
--- a/src/cmd/trace/regions.go
+++ b/src/cmd/trace/regions.go
@@ -72,10 +72,9 @@ func fingerprintRegion(r *trace.UserRegionSummary) regionFingerprint {
 func regionTopStackFrame(r *trace.UserRegionSummary) trace.StackFrame {
 	var frame trace.StackFrame
 	if r.Start != nil && r.Start.Stack() != trace.NoStack {
-		r.Start.Stack().Frames()(func(f trace.StackFrame) bool {
+		for f := range r.Start.Stack().Frames() {
 			frame = f
-			return false
-		})
+		}
 	}
 	return frame
 }
diff --git a/src/cmd/trace/viewer.go b/src/cmd/trace/viewer.go
index c367c7d636..6ce74b75b8 100644
--- a/src/cmd/trace/viewer.go
+++ b/src/cmd/trace/viewer.go
@@ -15,15 +15,14 @@ import (
 // used to store the frames to reduce allocations.
 func viewerFrames(stk trace.Stack) []*trace.Frame {
 	var frames []*trace.Frame
-	stk.Frames()(func(f trace.StackFrame) bool {
+	for f := range stk.Frames() {
 		frames = append(frames, &trace.Frame{
 			PC:   f.PC,
 			Fn:   f.Func,
 			File: f.File,
 			Line: int(f.Line),
 		})
-		return true
-	})
+	}
 	return frames
 }