os.Setenv("GO_ADDR2LINETEST_IS_ADDR2LINE", "1") // Set for subprocesses to inherit.
	os.Exit(m.Run())
}

// addr2linePath returns the path to the "addr2line" binary to run.
func addr2linePath(t testing.TB) string {
	t.Helper()
	testenv.MustHaveExec(t)

	addr2linePathOnce.Do(func() {
		addr2lineExePath, addr2linePathErr = os.Executable()
	})
	if addr2linePathErr != nil {
		t.Fatal(addr2linePathErr)
	}
	return addr2lineExePath
}

//	string encoding   |  ASCII |     UTF-8 |    binary
//	sub-second times  |     no |       yes |        no
//	sparse files      |     no |       yes |       yes
//
// The table's upper portion shows the [Header] fields, where each format reports
// the maximum number of bytes allowed for each string field and
// the integer type used to store each numeric field

// most-significant bit of the highest word, map to the full range of all
// 128 ASCII characters. The 128-bits of the upper 16 bytes will be zeroed,
// ensuring that any non-ASCII character will be reported as not in the set.
// This allocates a total of 32 bytes even though the upper half
// is unused to avoid bounds checks in asciiSet.contains.
type asciiSet [8]uint32

			} else if nextReg != int(reg) {
				p.errorf("incontiguous register in ARM64 register list: %s", name)
			}
			regCnt++
			nextReg = (nextReg + 1) % 32
		case sys.ARM:
			// Parse the upper and lower bounds.
			lo := p.registerNumber(tok.String())
			hi := lo
			if p.peek() == '-' {
				p.next()
				hi = p.registerNumber(p.next().String())
			}
			if hi < lo {
				lo, hi = hi, lo

	func C.GoBytes(unsafe.Pointer, C.int) []byte

As a special case, C.malloc does not call the C library malloc directly
but instead calls a Go helper function that wraps the C library malloc
but guarantees never to return nil. If C's malloc indicates out of memory,
the helper function crashes the program, like when Go itself runs out
of memory. Because C.malloc cannot fail, it has no two-result form
that returns errno.

			removeTag := func(v uint64) uint64 { return v }
			if goarch == "arm64" {
				for i := range symtab {
					if symtab[i].Name == "__hwasan_init" {
						// -fsanitize=hwaddress on ARM
						// uses the upper byte of a
						// memory address as a hardware
						// tag. Remove it so that
						// we can find the associated
						// data.
						removeTag = func(v uint64) uint64 { return v &^ (0xff << (64 - 8)) }