diff --git a/.gitignore b/.gitignore
new file mode 100644
index 000000000..5cd748c0c
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+cover/cover
diff --git a/cover/cover.go b/cover/cover.go
new file mode 100644
index 000000000..4c5fcfd7d
--- /dev/null
+++ b/cover/cover.go
@@ -0,0 +1,97 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"sort"
+
+	"golang.org/x/tools/cover"
+)
+
+func merge(p1, p2 *cover.Profile) *cover.Profile {
+	output := cover.Profile{
+		FileName: p1.FileName,
+		Mode:     p1.Mode,
+	}
+
+	i, j := 0, 0
+	for i < len(p1.Blocks) && j < len(p2.Blocks) {
+		bi, bj := p1.Blocks[i], p2.Blocks[j]
+		if bi.StartLine == bj.StartLine && bi.StartCol == bj.StartCol {
+
+			if bi.EndLine != bj.EndLine ||
+				bi.EndCol != bj.EndCol ||
+				bi.NumStmt != bj.NumStmt {
+				panic("Not run on same source!")
+			}
+
+			output.Blocks = append(output.Blocks, cover.ProfileBlock{
+				StartLine: bi.StartLine,
+				StartCol:  bi.StartCol,
+				EndLine:   bi.EndLine,
+				EndCol:    bi.EndCol,
+				NumStmt:   bi.NumStmt,
+				Count:     bi.Count + bj.Count,
+			})
+			i++
+			j++
+		} else if bi.StartLine < bj.StartLine || bi.StartLine == bj.StartLine && bi.StartCol < bj.StartCol {
+			output.Blocks = append(output.Blocks, bi)
+			i++
+		} else {
+			output.Blocks = append(output.Blocks, bj)
+			j++
+		}
+	}
+
+	for ; i < len(p1.Blocks); i++ {
+		output.Blocks = append(output.Blocks, p1.Blocks[i])
+	}
+
+	for ; j < len(p2.Blocks); j++ {
+		output.Blocks = append(output.Blocks, p2.Blocks[j])
+	}
+
+	return &output
+}
+
+func print(profiles []*cover.Profile) {
+	fmt.Println("mode: atomic")
+	for _, profile := range profiles {
+		for _, block := range profile.Blocks {
+			fmt.Printf("%s:%d.%d,%d.%d %d %d\n", profile.FileName, block.StartLine, block.StartCol,
+				block.EndLine, block.EndCol, block.NumStmt, block.Count)
+		}
+	}
+}
+
+// Copied from https://github.com/golang/tools/blob/master/cover/profile.go
+type byFileName []*cover.Profile
+
+func (p byFileName) Len() int           { return len(p) }
+func (p byFileName) Less(i, j int) bool { return p[i].FileName < p[j].FileName }
+func (p byFileName) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+func main() {
+	outputProfiles := map[string]*cover.Profile{}
+	for _, input := range os.Args[1:] {
+		inputProfiles, err := cover.ParseProfiles(input)
+		if err != nil {
+			panic(fmt.Sprintf("Error parsing %s: %v", input, err))
+		}
+		for _, ip := range inputProfiles {
+			op := outputProfiles[ip.FileName]
+			if op == nil {
+				outputProfiles[ip.FileName] = ip
+			} else {
+				outputProfiles[ip.FileName] = merge(op, ip)
+			}
+		}
+	}
+	profiles := make([]*cover.Profile, 0, len(outputProfiles))
+	for _, profile := range outputProfiles {
+		profiles = append(profiles, profile)
+	}
+	sort.Sort(byFileName(profiles))
+	print(profiles)
+}