github.com/wasilibs/nottinygc@v0.7.2-0.20240312114022-d59c9478ef51/gc_test.go

// Copyright wasilibs authors
// SPDX-License-Identifier: MIT

package nottinygc_test

import (
	"runtime"
	"testing"
)

// Some tests copied from Go that don't rely on internals

func TestGcDeepNesting(t *testing.T) {
	type T [2][2][2][2][2][2][2][2][2][2]*int
	a := new(T)

	// Prevent the compiler from applying escape analysis.
	// This makes sure new(T) is allocated on heap, not on the stack.
	t.Logf("%p", a)

	a[0][0][0][0][0][0][0][0][0][0] = new(int)
	*a[0][0][0][0][0][0][0][0][0][0] = 13
	runtime.GC()
	if *a[0][0][0][0][0][0][0][0][0][0] != 13 {
		t.Fail()
	}
}

func TestGcArraySlice(t *testing.T) {
	type X struct {
		buf     [1]byte
		nextbuf []byte
		next    *X
	}
	var head *X
	for i := 0; i < 10; i++ {
		p := &X{}
		p.buf[0] = 42
		p.next = head
		if head != nil {
			p.nextbuf = head.buf[:]
		}
		head = p
		runtime.GC()
	}
	for p := head; p != nil; p = p.next {
		if p.buf[0] != 42 {
			t.Fatal("corrupted heap")
		}
	}
}

func TestGcRescan(t *testing.T) {
	type X struct {
		c     chan error
		nextx *X
	}
	type Y struct {
		X
		nexty *Y
		p     *int
	}
	var head *Y
	for i := 0; i < 10; i++ {
		p := &Y{}
		p.c = make(chan error)
		if head != nil {
			p.nextx = &head.X
		}
		p.nexty = head
		p.p = new(int)
		*p.p = 42
		head = p
		runtime.GC()
	}
	for p := head; p != nil; p = p.nexty {
		if *p.p != 42 {
			t.Fatal("corrupted heap")
		}
	}
}