// Test that on the first invocation of a OnceFunc, the stack trace goes all
	// the way to the origin of the panic.
	f := sync.OnceFunc(onceFuncPanic)

	defer func() {
		if p := recover(); p != "x" {
			t.Fatalf("want panic %v, got %v", "x", p)
		}
		stack := debug.Stack()
		want := "sync_test.onceFuncPanic"
		if !bytes.Contains(stack, []byte(want)) {
			t.Fatalf("want stack containing %v, got:\n%s", want, string(stack))
		}

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

// Issue 2444
// Issue 4666: issue with arrays of exactly 4GB.

package main

var z [10 << 20]byte

func main() { // GC_ERROR "stack frame too large"
	// seq 1 206 | sed 's/.*/	var x& [10<<20]byte/'
	// seq 1 206 | sed 's/.*/	z = x&/'
	var x1 [10<<20]byte
	var x2 [10<<20]byte
	var x3 [10<<20]byte
	var x4 [10<<20]byte
	var x5 [10<<20]byte

	if err := syscall.Close(*pipeFD); err != nil {
		panic(fmt.Sprintf("error closing control pipe fd %d: %v", *pipeFD, err))
	}

	for {}
}
`

// TestGdbCoreSignalBacktrace tests that gdb can unwind the stack correctly
// through a signal handler in a core file
func TestGdbCoreSignalBacktrace(t *testing.T) {
	if runtime.GOOS != "linux" {
		// N.B. This test isn't fundamentally Linux-only, but it needs

		}
		if runtime.Compiler == "gccgo" {
			runtime.Gosched()
		}
	}
}

// mutexHog2 is almost identical to mutexHog but we keep them separate
// in order to distinguish them with function names in the stack trace.
// We make them slightly different, using Sink, because otherwise
// gccgo -c opt will merge them.
func mutexHog2(mu1, mu2 *sync.Mutex, start time.Time, dt time.Duration) {
	atomic.AddUint32(&Sink, 2)

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Trace stack table and acquisition.

package runtime

import (
	"internal/abi"
	"internal/goarch"
	"unsafe"
)

// traceTypeTable maps stack traces (arrays of PC's) to unique uint32 ids.
// It is lock-free for reading.
type traceTypeTable struct {
	tab traceMap
}

	return
}

// ReachableBlocks returns the reachable blocks in f.
func ReachableBlocks(f *Func) []bool {
	reachable := make([]bool, f.NumBlocks())
	reachable[f.Entry.ID] = true
	p := make([]*Block, 0, 64) // stack-like worklist
	p = append(p, f.Entry)
	for len(p) > 0 {
		// Pop a reachable block
		b := p[len(p)-1]
		p = p[:len(p)-1]
		// Mark successors as reachable
		s := b.Succs
		if b.Kind == BlockFirst {
			s = s[:1]

	}

	values := []int64{0, 0, 0, 0}
	var locs []uint64
	for _, r := range p {
		hideRuntime := true
		for tries := 0; tries < 2; tries++ {
			stk := r.Stack
			// For heap profiles, all stack
			// addresses are return PCs, which is
			// what appendLocsForStack expects.
			if hideRuntime {
				for i, addr := range stk {

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

package runtime

import "unsafe"

// This file handles some syscalls from the syscall package
// Especially, syscalls use during forkAndExecInChild which must not split the stack

//go:cgo_import_dynamic libc_chdir chdir "libc.a/shr_64.o"
//go:cgo_import_dynamic libc_chroot chroot "libc.a/shr_64.o"
//go:cgo_import_dynamic libc_dup2 dup2 "libc.a/shr_64.o"

}

func (r *Config) HasCounterPrefix(program, prefix string) bool {
	return r.pgcounterprefix[pgkey{program, prefix}]
}

func (r *Config) HasStack(program, stack string) bool {
	return r.pgstack[pgkey{program, stack}]
}

func (r *Config) Rate(program, name string) float64 {
	return r.rate[pgkey{program, name}]
}

func set(slice []string) map[string]bool {

	i = nil
	return i
}

func g() {
	h := E() // ERROR "inlining call to E" "T\(0\) does not escape"
	h.M()    // ERROR "devirtualizing h.M to T" "inlining call to T.M"

	// BAD: T(0) could be stack allocated.
	i := F(T(0)) // ERROR "inlining call to F" "T\(0\) escapes to heap"

	// Testing that we do NOT devirtualize here:
	i.M()