// Package platform includes runtime-specific code needed for the compiler or otherwise.
//
// Note: This is a dependency-free alternative to depending on parts of Go's x/sys.
// See /RATIONALE.md for more context.
package platform

import (
	"runtime"
)

// archRequirementsVerified is set by platform-specific init to true if the platform is supported
var archRequirementsVerified bool

// CompilerSupported includes constraints here and also the assembler.
func CompilerSupported() bool {
	switch runtime.GOOS {
	case "linux", "darwin", "freebsd", "netbsd", "dragonfly", "windows":
		return archRequirementsVerified
	case "solaris", "illumos":
		return runtime.GOARCH == "amd64" && archRequirementsVerified
	default:
		return false
	}
}

// MmapCodeSegment copies the code into the executable region and returns the byte slice of the region.
//
// See https://man7.org/linux/man-pages/man2/mmap.2.html for mmap API and flags.
func MmapCodeSegment(size int) ([]byte, error) {
	if size == 0 {
		panic("BUG: MmapCodeSegment with zero length")
	}
	if runtime.GOARCH == "amd64" {
		return mmapCodeSegmentAMD64(size)
	} else {
		return mmapCodeSegmentARM64(size)
	}
}

// MunmapCodeSegment unmaps the given memory region.
func MunmapCodeSegment(code []byte) error {
	if len(code) == 0 {
		panic("BUG: MunmapCodeSegment with zero length")
	}
	return munmapCodeSegment(code)
}