}

	// Sort variables in descending alignment order, so we can optimally
	// pack variables into the frame.
	if a.Type().Alignment() != b.Type().Alignment() {
		return a.Type().Alignment() > b.Type().Alignment()
	}

	// Sort normal variables before open-coded-defer slots, so that the
	// latter are grouped together and near the top of the frame (to
	// minimize varint encoding of their varp offset).
	if a.OpenDeferSlot() != b.OpenDeferSlot() {

type stack struct {
	pcs []uint64
}

func (s stack) String() string {
	var sb strings.Builder
	for _, frame := range s.pcs {
		fmt.Fprintf(&sb, "\t%#v\n", frame)
	}
	return sb.String()
}

// frame represents a single stack frame.
type frame struct {
	pc     uint64
	funcID stringID
	fileID stringID
	line   uint64

	}

	frames := f.dwarfSourceLine(addr)
	if frames != nil {
		return frames, nil
	}

	return nil, fmt.Errorf("no line information for PC=%#x", addr)
}

// dwarfSourceLine tries to get file/line information using DWARF.
// This is for C functions that appear in the profile.
// Returns nil if there is no information available.
func (f *file) dwarfSourceLine(addr uint64) []driver.Frame {

		return false
	}

	switch status := sigctxtStatus(ctxt); status {
	case 0:
		// Frame is ready. Copy the arguments to the frame and to registers.
		// Call the debug function.
		h.debugCallRun(ctxt)
	case 1:
		// Function returned. Copy frame and result registers back out.
		h.debugCallReturn(ctxt)
	case 2:
		// Function panicked. Copy panic out.
		h.debugCallPanicOut(ctxt)

// Copyright 2014 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.

package trace

// Frame is a frame in stack traces.
type Frame struct {
	PC   uint64
	Fn   string
	File string
	Line int
}

const (
	// Special P identifiers:
	FakeP    = 1000000 + iota
	TimerP   // depicts timer unblocks
	NetpollP // depicts network unblocks

		t.Fatalf("unexpected: %v %d %v", err, n, buf)
	}
	// read the remaining frame
	buf = make([]byte, 2)
	if n, err := r.Read(buf); err != nil && n != 2 && bytes.Equal(buf, []byte{0x03, 0x04}) {
		t.Fatalf("unexpected: %v %d %v", err, n, buf)
	}
	// read with buffer equal to frame
	buf = make([]byte, 3)
	if n, err := r.Read(buf); err != nil && n != 3 && bytes.Equal(buf, []byte{0x05, 0x06, 0x07}) {

	if err != nil {
		return Event{}, err
	}
	if spec.IsStack {
		len := int(args[1])
		for i := 0; i < len; i++ {
			// Each stack frame has four args: pc, func ID, file ID, line number.
			frame, err := r.readArgs(4)
			if err != nil {
				return Event{}, err
			}
			args = append(args, frame...)
		}
	}
	var data []byte
	if spec.HasData {
		data, err = r.readData()
		if err != nil {
			return Event{}, err
		}
	}

	RET

// func cgocallback(fn, frame unsafe.Pointer, ctxt uintptr)
// See cgocall.go for more details.
TEXT ·cgocallback(SB),NOSPLIT,$24-24
	NO_LOCAL_POINTERS

	// Skip cgocallbackg, just dropm when fn is nil, and frame is the saved g.
	// It is used to dropm while thread is exiting.
	MOVD	fn+0(FP), R5
	CMP	R5, $0
	BNE	loadg
	// Restore the g from frame.
	MOVD	frame+8(FP), g
	BR	dropm

loadg:

TEXT runtime·retpolineR8(SB),NOSPLIT|NOFRAME,$0; RETPOLINE(8)
TEXT runtime·retpolineR9(SB),NOSPLIT|NOFRAME,$0; RETPOLINE(9)
TEXT runtime·retpolineR10(SB),NOSPLIT|NOFRAME,$0; RETPOLINE(10)
TEXT runtime·retpolineR11(SB),NOSPLIT|NOFRAME,$0; RETPOLINE(11)
TEXT runtime·retpolineR12(SB),NOSPLIT|NOFRAME,$0; RETPOLINE(12)
TEXT runtime·retpolineR13(SB),NOSPLIT|NOFRAME,$0; RETPOLINE(13)

	{"-O2"},
	{"-Osmall"},
	{"-W"},
	{"-Wall"},
	{"-Wp,-Dfoo=bar"},
	{"-Wp,-Ufoo"},
	{"-Wp,-Dfoo1"},
	{"-Wp,-Ufoo1"},
	{"-flto"},
	{"-fobjc-arc"},
	{"-fno-objc-arc"},
	{"-fomit-frame-pointer"},
	{"-fno-omit-frame-pointer"},
	{"-fpic"},
	{"-fno-pic"},
	{"-fPIC"},
	{"-fno-PIC"},
	{"-fpie"},
	{"-fno-pie"},
	{"-fPIE"},
	{"-fno-PIE"},
	{"-fsplit-stack"},
	{"-fno-split-stack"},
	{"-fstack-xxx"},