cmd/compile: add race instrumentation during walkCompare

So the racy usage could be detected after re-writing "==" to
runtime.memequal call.

Updates #61204

Change-Id: Idb4ac37e55813cc87f9d16aa656fb447edf69ea1
Reviewed-on: https://go-review.googlesource.com/c/go/+/601117
Reviewed-by: Egon Elbre <egonelbre@gmail.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/src/runtime/race/output_test.go b/src/runtime/race/output_test.go
index 0ee0f41334..0d5c9096f0 100644
--- a/src/runtime/race/output_test.go
+++ b/src/runtime/race/output_test.go
@@ -477,4 +477,58 @@ Previous write at 0x[0-9,a-f]+ by main goroutine:
       .*/main.go:10 \+0x[0-9,a-f]+
 
 `}},
+	{"non_inline_array_compare", "run", "", "atexit_sleep_ms=0", `
+package main
+
+import (
+	"math/rand/v2"
+)
+
+var x = [1024]byte{}
+
+var ch = make(chan bool)
+
+func main() {
+	started := make(chan struct{})
+	go func() {
+		close(started)
+		var y = [len(x)]byte{}
+		eq := x == y
+		ch <- eq
+	}()
+	<-started
+	x[rand.IntN(len(x))]++
+	println(<-ch)
+}
+`, []string{`==================
+WARNING: DATA RACE
+`}},
+	{"non_inline_struct_compare", "run", "", "atexit_sleep_ms=0", `
+package main
+
+import "math/rand/v2"
+
+type S struct {
+	a [1024]byte
+}
+
+var x = S{a: [1024]byte{}}
+
+var ch = make(chan bool)
+
+func main() {
+	started := make(chan struct{})
+	go func() {
+		close(started)
+		var y = S{a: [len(x.a)]byte{}}
+		eq := x == y
+		ch <- eq
+	}()
+	<-started
+	x.a[rand.IntN(len(x.a))]++
+	println(<-ch)
+}
+`, []string{`==================
+WARNING: DATA RACE
+`}},
 }