// NewLexer returns a lexer for the named file and the given link context.
func NewLexer(name string) TokenReader {
	input := NewInput(name)
	fd, err := os.Open(name)
	if err != nil {
		log.Fatalf("%s\n", err)
	}
	input.Push(NewTokenizer(name, fd, fd))
	return input
}

// The other files in this directory each contain an implementation of TokenReader.

	// Also check that mixed pushes and pops work correctly.
	for _, s := range tests {
		h := heap{}
		for i := 0; i < len(s)/2; i++ {
			// two pushes, one pop
			h.push(s[2*i])
			if !verify(&h, 0) {
				t.Errorf("heap invariant violated: %v", h)
			}
			h.push(s[2*i+1])
			if !verify(&h, 0) {
				t.Errorf("heap invariant violated: %v", h)
			}
			h.pop()
			if !verify(&h, 0) {
				t.Errorf("heap invariant violated: %v", h)

			edges = append(edges, edge{from: x, to: s})
			if _, ok := m[s]; ok {
				continue // already found
			}
			q = append(q, s)
			m[s] = 0 // mark as found
		}
		m[x] = ndeps
		if ndeps == 0 {
			h.push(ldr, x)
		}
	}

	// Sort edges so we can look them up by edge destination.
	sort.Slice(edges, func(i, j int) bool {
		return edges[i].to < edges[j].to
	})

	// Figure out the schedule.

		for _, e := range s {
			c := e.b
			if int(c.ID) >= len(reachable) {
				f.Fatalf("block %s >= f.NumBlocks()=%d?", c, len(reachable))
			}
			if !reachable[c.ID] {
				reachable[c.ID] = true
				p = append(p, c) // push
			}
		}
	}
	return reachable
}

// liveValues returns the live values in f and a list of values that are eligible
// to be statements in reversed data flow order.

	for _, b := range f.Blocks {
		if exit.contains(b.ID) {
			// exit blocks are always scheduled last
			continue
		}
		indegree[b.ID] = len(b.Preds)
		if len(b.Preds) == 0 {
			// Push an element to the tail of the queue.
			zerodegree = append(zerodegree, b.ID)
		} else {
			posdegree.add(b.ID)
		}
	}

	bid := f.Entry.ID
blockloop:
	for {
		// add block to schedule

		for _, v := range b.Values {
			if v.Op == OpLoadReg && r[v.ID].String() == "g" {
				t.Errorf("Saw OpLoadReg targeting g register: %s", v.LongString())
			}
		}
	}
}

// Test to make sure we don't push spills into loops.
// See issue #19595.
func TestSpillWithLoop(t *testing.T) {
	c := testConfig(t)
	f := c.Fun("entry",
		Bloc("entry",
			Valu("mem", OpInitMem, types.TypeMem, 0, nil),

func (d TestFrontend) Debug_checknil() bool                               { return false }

func (d TestFrontend) Func() *ir.Func {
	return d.f
}

var testTypes Types

func init() {
	// TODO(mdempsky): Push into types.InitUniverse or typecheck.InitUniverse.
	types.PtrSize = 8
	types.RegSize = 8
	types.MaxWidth = 1 << 50

	base.Ctxt = &obj.Link{Arch: &obj.LinkArch{Arch: &sys.Arch{Alignment: 1, CanMergeLoads: true}}}

	// template. So any instantiation cycles must occur within a single
	// package. Accordingly, we can ignore instantiations of imported
	// type parameters.
	//
	// TODO(mdempsky): Push this check up into recordInstance? All type
	// parameters in a list will appear in the same package.
	if tpar.Obj().Pkg() != pkg {
		return
	}

)

// A Stack is a stack of TokenReaders. As the top TokenReader hits EOF,
// it resumes reading the next one down.
type Stack struct {
	tr []TokenReader
}

// Push adds tr to the top (end) of the input stack. (Popping happens automatically.)
func (s *Stack) Push(tr TokenReader) {
	s.tr = append(s.tr, tr)
}

func (s *Stack) Next() ScanToken {
	tos := s.tr[len(s.tr)-1]
	tok := tos.Next()

package ld

import "cmd/link/internal/loader"

// Min-heap implementation, for the deadcode pass.
// Specialized for loader.Sym elements.

type heap []loader.Sym

func (h *heap) push(s loader.Sym) {
	*h = append(*h, s)
	// sift up
	n := len(*h) - 1
	for n > 0 {
		p := (n - 1) / 2 // parent
		if (*h)[p] <= (*h)[n] {
			break
		}
		(*h)[n], (*h)[p] = (*h)[p], (*h)[n]
		n = p
	}
}