)

func StackNosplit(race bool) int {
	// This arithmetic must match that in runtime/stack.go:stackNosplit.
	return abi.StackNosplitBase * stackGuardMultiplier(race)
}

// stackGuardMultiplier returns a multiplier to apply to the default
// stack guard size. Larger multipliers are used for non-optimized
// builds that have larger stack frames or for specific targets.
func stackGuardMultiplier(race bool) int {

// license that can be found in the LICENSE file.

package codegen

import "runtime"

// This file contains code generation tests related to the use of the
// stack.

// Check that stack stores are optimized away.

// 386:"TEXT\t.*, [$]0-"
// amd64:"TEXT\t.*, [$]0-"
// arm:"TEXT\t.*, [$]-4-"
// arm64:"TEXT\t.*, [$]0-"
// mips:"TEXT\t.*, [$]-4-"
// ppc64x:"TEXT\t.*, [$]0-"

	// allocation.
	if newsize < fixedStack {
		return
	}
	// Compute how much of the stack is currently in use and only
	// shrink the stack if gp is using less than a quarter of its
	// current stack. The currently used stack includes everything
	// down to the SP plus the stack guard space that ensures
	// there's room for nosplit functions.
	avail := gp.stack.hi - gp.stack.lo

import (
	"text/scanner"

	"cmd/internal/src"
)

// 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]

	//
	// This value must be multiplied by the stack guard multiplier, so do not
	// use it directly. See runtime/stack.go:stackNosplit and
	// cmd/internal/objabi/stack.go:StackNosplit.
	StackNosplitBase = 800

	// We have three different sequences for stack bounds checks, depending on
	// whether the stack frame of a function is small, big, or huge.

	// After a stack split check the SP is allowed to be StackSmall bytes below

)

// PrintStack prints to standard error the stack trace returned by runtime.Stack.
func PrintStack() {
	os.Stderr.Write(Stack())
}

// Stack returns a formatted stack trace of the goroutine that calls it.
// It calls [runtime.Stack] with a large enough buffer to capture the entire trace.
func Stack() []byte {
	buf := make([]byte, 1024)
	for {
		n := runtime.Stack(buf, false)
		if n < len(buf) {
			return buf[:n]
		}

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Test stack splitting code.
// Try to tickle stack splitting bugs by doing
// go, defer, and closure calls at different stack depths.

package main

type T [20]int

func g(c chan int, t T) {
	s := 0
	for i := 0; i < len(t); i++ {
		s += t[i]
	}
	c <- s
}

			}

			if len(stack) > 0 {
				stack += " "
			}
			stack += FmtSprintf("%s:%d", name, line-tiuStart)
		}

		if stack != prevStack {
			prevStack = stack

			t.Logf("tiuTest+%#x: %s", pc-pc1, stack)

			if _, ok := want[stack]; ok {
				want[stack]++
			}
		}
	}

	// Check that we got all the stacks we wanted.
	for stack, count := range want {
		if count == 0 {

	// Check special cases.
	if sym == sc.morestack {
		// morestack looks like it calls functions, but they
		// either happen only when already on the system stack
		// (where there is ~infinite space), or after
		// switching to the system stack. Hence, its stack
		// height on the user stack is 0.
		return 0, nil
	}
	if sym == stackCheckIndirect {
		// Assume that indirect/closure calls are always to

// explaining why.
//
//go:nosplit
func debugCallCheck(pc uintptr) string {
	// No user calls from the system stack.
	if getg() != getg().m.curg {
		return debugCallSystemStack
	}
	if sp := getcallersp(); !(getg().stack.lo < sp && sp <= getg().stack.hi) {
		// Fast syscalls (nanotime) and racecall switch to the
		// g0 stack without switching g. We can't safely make
		// a call in this state. (We can't even safely
		// systemstack.)