delve/pkg/dwarf/frame/entries_test.go

package frame

import (
	"encoding/binary"
	"io/ioutil"
	"os"
	"testing"
)

func TestFDEForPC(t *testing.T) {
	frames := NewFrameIndex()
	frames = append(frames,
		&FrameDescriptionEntry{begin: 10, size: 40},
		&FrameDescriptionEntry{begin: 50, size: 50},
		&FrameDescriptionEntry{begin: 100, size: 100},
		&FrameDescriptionEntry{begin: 300, size: 10})

	for _, test := range []struct {
		pc  uint64
		fde *FrameDescriptionEntry
	}{
		{0, nil},
		{9, nil},
		{10, frames[0]},
		{35, frames[0]},
		{49, frames[0]},
		{50, frames[1]},
		{75, frames[1]},
		{100, frames[2]},
		{199, frames[2]},
		{200, nil},
		{299, nil},
		{300, frames[3]},
		{309, frames[3]},
		{310, nil},
		{400, nil}} {

		out, err := frames.FDEForPC(test.pc)
		if test.fde != nil {
			if err != nil {
				t.Fatal(err)
			}
			if out != test.fde {
				t.Errorf("[pc = %#x] got incorrect fde\noutput:\t%#v\nexpected:\t%#v", test.pc, out, test.fde)
			}
		} else {
			if err == nil {
				t.Errorf("[pc = %#x] expected error got fde %#v", test.pc, out)
			}
		}
	}
}

func BenchmarkFDEForPC(b *testing.B) {
	f, err := os.Open("testdata/frame")
	if err != nil {
		b.Fatal(err)
	}
	defer f.Close()

	data, err := ioutil.ReadAll(f)
	if err != nil {
		b.Fatal(err)
	}
	fdes := Parse(data, binary.BigEndian, 0)

	for i := 0; i < b.N; i++ {
		// bench worst case, exhaustive search
		_, _ = fdes.FDEForPC(0x455555555)
	}
}