//go:build goexperiment.arenas

/*
The arena package provides the ability to allocate memory for a collection
of Go values and free that space manually all at once, safely. The purpose
of this functionality is to improve efficiency: manually freeing memory
before a garbage collection delays that cycle. Less frequent cycles means
the CPU cost of the garbage collector is incurred less frequently.

	type span struct {
		start int
		end   int
	}
	spans := make([]span, 0, 32)

	// Find the field start and end indices.
	// Doing this in a separate pass (rather than slicing the string s
	// and collecting the result substrings right away) is significantly
	// more efficient, possibly due to cache effects.
	start := -1 // valid span start if >= 0
	for i := 0; i < len(s); {
		size := 1
		r := rune(s[i])

argument, so that the host linker will be able to find 'sin' in the
math library.

cmd/link Command Line Interface

The go command and any other Go-aware build systems invoke cmd/link
to link a collection of packages into a single binary. By default, cmd/link will
present the same interface it does today:

	cmd/link main.a

produces a file named a.out, even if cmd/link does so by invoking the host

	} else {
		sn = sn[:maxNanoSecondDigits] // Right truncate
	}
	nsecs, _ := strconv.ParseInt(sn, 10, 64) // Must succeed
	if len(ss) > 0 && ss[0] == '-' {
		return time.Unix(secs, -1*nsecs), nil // Negative correction
	}
	return time.Unix(secs, nsecs), nil
}

// formatPAXTime converts ts into a time of the form %d.%d as described in the
// PAX specification. This function is capable of negative timestamps.

Translation of parameters and the return value follows the type
translation above except that arrays passed as parameters translate
explicitly in Go to pointers to arrays, as they do (implicitly) in C.

Garbage collection is the big problem.  It is fine for the Go world to
have pointers into the C world and to free those pointers when they
are no longer needed.  To help, the Go code can define Go objects

var tmpdir string

var (
	devID    string
	appID    string
	teamID   string
	bundleID string
	deviceID string
)

// lock is a file lock to serialize iOS runs. It is global to avoid the
// garbage collector finalizing it, closing the file and releasing the
// lock prematurely.
var lock *os.File

func main() {
	log.SetFlags(0)
	log.SetPrefix("go_ios_exec: ")
	if debug {
		log.Println(strings.Join(os.Args, " "))