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// run -gcflags=-d=maymorestack=main.mayMoreStack
// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Test the maymorestack testing hook by injecting a hook that counts
// how many times it is called and checking that count.
package main
import "runtime"
var count uint32
//go:nosplit
func mayMoreStack() {
count++
}
func main() {
const wantCount = 128
anotherFunc(wantCount - 1) // -1 because the call to main already counted
if count == 0 {
panic("mayMoreStack not called")
} else if count != wantCount {
println(count, "!=", wantCount)
panic("wrong number of calls to mayMoreStack")
}
}
//go:noinline
func anotherFunc(n int) {
// Trigger a stack growth on at least some calls to
// anotherFunc to test that mayMoreStack is called outside the
// morestack loop. It's also important that it is called
// before (not after) morestack, but that's hard to test.
var x [1 << 10]byte
if n > 1 {
anotherFunc(n - 1)
}
runtime.KeepAlive(x)
}
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