package ssa

import (
	"cmd/compile/internal/ir"
	"cmd/internal/obj/s390x"
	"math"
	"math/bits"
)

// checkFunc checks invariants of f.
func checkFunc(f *Func) {
	blockMark := make([]bool, f.NumBlocks())
	valueMark := make([]bool, f.NumValues())

	for _, b := range f.Blocks {
		if blockMark[b.ID] {
			f.Fatalf("block %s appears twice in %s!", b, f.Name)
		}
		blockMark[b.ID] = true
		if b.Func != f {

	if lc, _ := f.Cache.Liveness.(*livenessFuncCache); lc == nil {
		// Prep the cache so liveness can fill it later.
		f.Cache.Liveness = new(livenessFuncCache)
	} else {
		if cap(lc.be) >= f.NumBlocks() {
			lv.be = lc.be[:f.NumBlocks()]
		}
		lv.livenessMap = Map{
			Vals:         lc.livenessMap.Vals,
			UnsafeVals:   lc.livenessMap.UnsafeVals,
			UnsafeBlocks: lc.livenessMap.UnsafeBlocks,

		CanonicalLocalSlots:  make(map[LocalSlot]*LocalSlot),
		CanonicalLocalSplits: make(map[LocalSlotSplitKey]*LocalSlot),
	}
}

// NumBlocks returns an integer larger than the id of any Block in the Func.
func (f *Func) NumBlocks() int {
	return f.bid.num()
}

// NumValues returns an integer larger than the id of any Value in the Func.
func (f *Func) NumValues() int {
	return f.vid.num()
}

// basic blocks. Figure out a way to make this function (or, more precisely, the user
// of this function) require only linear size & time.
func (s *stackAllocState) computeLive(spillLive [][]ID) {
	s.live = make([][]ID, s.f.NumBlocks())
	var phis []*Value
	live := s.f.newSparseSet(s.f.NumValues())
	defer s.f.retSparseSet(live)
	t := s.f.newSparseSet(s.f.NumValues())
	defer s.f.retSparseSet(t)

	t.edges = append(t.edges, Edge{f.Entry, 0})
	t.defUse = make(map[*Value][]*Value)
	t.defBlock = make(map[*Value][]*Block)
	t.latticeCells = make(map[*Value]lattice)
	t.visitedBlock = f.Cache.allocBoolSlice(f.NumBlocks())
	defer f.Cache.freeBoolSlice(t.visitedBlock)

	// build it early since we rely heavily on the def-use chain later
	t.buildDefUses()

	// pick up either an edge or SSA value from worklist, process it
	for {

	paxSchilyXattr = "SCHILY.xattr."

	// Keywords for GNU sparse files in a PAX extended header.
	paxGNUSparse          = "GNU.sparse."
	paxGNUSparseNumBlocks = "GNU.sparse.numblocks"
	paxGNUSparseOffset    = "GNU.sparse.offset"
	paxGNUSparseNumBytes  = "GNU.sparse.numbytes"
	paxGNUSparseMap       = "GNU.sparse.map"
	paxGNUSparseName      = "GNU.sparse.name"