return nil, nil
	}

	// Find assembly files to work on.
	var sfiles []string
	for _, fname := range pass.OtherFiles {
		if strings.HasSuffix(fname, ".s") && pass.Pkg.Path() != "runtime" {
			sfiles = append(sfiles, fname)
		}
	}

	for _, fname := range sfiles {
		content, tf, err := analysisutil.ReadFile(pass, fname)
		if err != nil {
			return nil, err
		}

		lines := strings.SplitAfter(string(content), "\n")

	MOVW	R2, ret+8(FP)
	RET

// cgocallback(fn, frame unsafe.Pointer, ctxt uintptr)
// See cgocall.go for more details.
TEXT ·cgocallback(SB),NOSPLIT,$12-12
	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.
	MOVW	fn+0(FP), R5
	BNE	R5, loadg
	// Restore the g from frame.
	MOVW	frame+4(FP), g
	JMP	dropm

loadg:

// 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
		}
	}

     *
     * @see Throwable#toString()
     */
    String getHeader();

    /**
     * Stack frames from the original exception.
     */
    List<StackTraceElement> getStackTrace();

    /**
     * Relevance of a given stack frame in the {@link #getStackTrace() stack trace}.
     */
    StackTraceRelevance getStackTraceRelevance(int frameIndex);

    /**

	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"},

	}
	if a.srcStackOffset+a.len == b.srcStackOffset && a.dstStackOffset+a.len == b.dstStackOffset {
		a.len += b.len
		return true
	}
	return false
}

// abiDesc specifies how to translate from a C frame to a Go
// frame. This does not specify how to translate back because
// the result is always a uintptr. If the C ABI is fastcall,
// this assumes the four fastcall registers were first spilled
// to the shadow space.