pkg/cover: implement function coverage calculation

2 files changed, 109 insertions, 12 deletions

diff --git a/pkg/cover/report.go b/pkg/cover/report.go
index a302b7013..666babb02 100644
--- a/pkg/cover/report.go
+++ b/pkg/cover/report.go
@@ -6,6 +6,7 @@ package cover
 import (
 	"bufio"
 	"bytes"
+	"encoding/csv"
 	"fmt"
 	"html"
 	"html/template"
@@ -41,6 +42,13 @@ type symbol struct {
 	end   uint64
 }
 
+var CSVHeader = []string{
+	"Filename",
+	"Function",
+	"Covered PCs",
+	"Total PCs",
+}
+
 func MakeReportGenerator(target *targets.Target, kernelObject, srcDir, buildDir string) (*ReportGenerator, error) {
 	rg := &ReportGenerator{
 		target:   target,
@@ -70,12 +78,18 @@ func MakeReportGenerator(target *targets.Target, kernelObject, srcDir, buildDir
 
 type file struct {
 	lines       map[int]line
+	functions   map[string]*function
 	totalPCs    map[uint64]bool
 	coverPCs    map[uint64]bool
 	totalInline map[int]bool
 	coverInline map[int]bool
 }
 
+type function struct {
+	totalPCs map[uint64]bool
+	coverPCs map[uint64]bool
+}
+
 type line struct {
 	count         map[int]bool
 	prog          int
@@ -83,7 +97,23 @@ type line struct {
 	symbolCovered bool
 }
 
-func (rg *ReportGenerator) Do(w io.Writer, progs []Prog) error {
+func (rg *ReportGenerator) DoHTML(buf io.Writer, progs []Prog) error {
+	files, err := rg.prepareFileMap(progs)
+	if err != nil {
+		return err
+	}
+	return rg.generateHTML(buf, progs, files)
+}
+
+func (rg *ReportGenerator) DoCSV(buf io.Writer, progs []Prog) error {
+	files, err := rg.prepareFileMap(progs)
+	if err != nil {
+		return err
+	}
+	return rg.generateCSV(buf, progs, files)
+}
+
+func (rg *ReportGenerator) prepareFileMap(progs []Prog) (map[string]*file, error) {
 	coveredPCs := make(map[uint64]bool)
 	allPCs := make(map[uint64]bool)
 	symbols := make(map[uint64]bool)
@@ -113,10 +143,10 @@ func (rg *ReportGenerator) Do(w io.Writer, progs []Prog) error {
 		}
 	}
 	if len(allPCs) == 0 {
-		return fmt.Errorf("no coverage collected so far")
+		return nil, fmt.Errorf("no coverage collected so far")
 	}
 	if len(coveredPCs) == 0 {
-		return fmt.Errorf("coverage (%v) doesn't match coverage callbacks", len(allPCs))
+		return nil, fmt.Errorf("coverage (%v) doesn't match coverage callbacks", len(allPCs))
 	}
 	for pc, frames := range rg.pcs {
 		covered := coveredPCs[pc]
@@ -133,6 +163,8 @@ func (rg *ReportGenerator) Do(w io.Writer, progs []Prog) error {
 					f.coverPCs[pc] = true
 				}
 			}
+			function := getFunction(f.functions, frame.Func)
+			function.totalPCs[pc] = true
 			if !covered {
 				ln := f.lines[frame.Line]
 				if !frame.Inline || len(ln.count) == 0 {
@@ -140,10 +172,12 @@ func (rg *ReportGenerator) Do(w io.Writer, progs []Prog) error {
 					ln.symbolCovered = symbols[rg.findSymbol(pc)]
 					f.lines[frame.Line] = ln
 				}
+			} else {
+				function.coverPCs[pc] = true
 			}
 		}
 	}
-	return rg.generate(w, progs, files)
+	return files, nil
 }
 
 func getFile(files map[string]*file, name string) *file {
@@ -151,6 +185,7 @@ func getFile(files map[string]*file, name string) *file {
 	if f == nil {
 		f = &file{
 			lines:       make(map[int]line),
+			functions:   make(map[string]*function),
 			totalPCs:    make(map[uint64]bool),
 			coverPCs:    make(map[uint64]bool),
 			totalInline: make(map[int]bool),
@@ -161,7 +196,43 @@ func getFile(files map[string]*file, name string) *file {
 	return f
 }
 
-func (rg *ReportGenerator) generate(w io.Writer, progs []Prog, files map[string]*file) error {
+func getFunction(functions map[string]*function, name string) *function {
+	f := functions[name]
+	if f == nil {
+		f = &function{
+			totalPCs: make(map[uint64]bool),
+			coverPCs: make(map[uint64]bool),
+		}
+		functions[name] = f
+	}
+	return f
+}
+
+func (rg *ReportGenerator) generateCSV(w io.Writer, progs []Prog, files map[string]*file) error {
+	data := [][]string{
+		CSVHeader,
+	}
+
+	for fname, file := range files {
+		for funcName, function := range file.functions {
+			line := []string{filepath.Clean(fname), funcName,
+				strconv.Itoa(len(function.coverPCs)),
+				strconv.Itoa(len(function.totalPCs))}
+			data = append(data, line)
+		}
+	}
+	writer := csv.NewWriter(w)
+	defer writer.Flush()
+
+	err := writer.WriteAll(data)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (rg *ReportGenerator) generateHTML(w io.Writer, progs []Prog, files map[string]*file) error {
 	d := &templateData{
 		Root: new(templateDir),
 	}
diff --git a/pkg/cover/report_test.go b/pkg/cover/report_test.go
index d7a893352..f2253032d 100644
--- a/pkg/cover/report_test.go
+++ b/pkg/cover/report_test.go
@@ -9,9 +9,11 @@ package cover
 
 import (
 	"bytes"
+	"encoding/csv"
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"reflect"
 	"regexp"
 	"runtime"
 	"strconv"
@@ -88,7 +90,7 @@ func TestReportGenerator(t *testing.T) {
 }
 
 func testReportGenerator(t *testing.T, target *targets.Target, test Test) {
-	rep, err := generateReport(t, target, test)
+	rep, csv, err := generateReport(t, target, test)
 	if err != nil {
 		if test.Result == "" {
 			t.Fatalf("expected no error, but got:\n%v", err)
@@ -101,6 +103,7 @@ func testReportGenerator(t *testing.T, target *targets.Target, test Test) {
 	if test.Result != "" {
 		t.Fatalf("got no error, but expected %q", test.Result)
 	}
+	checkCSVReport(t, csv)
 	_ = rep
 }
 
@@ -136,7 +139,7 @@ void __sanitizer_cov_trace_pc() { printf("%llu", (long long)__builtin_return_add
 	return bin
 }
 
-func generateReport(t *testing.T, target *targets.Target, test Test) ([]byte, error) {
+func generateReport(t *testing.T, target *targets.Target, test Test) ([]byte, []byte, error) {
 	dir, err := ioutil.TempDir("", "syz-cover-test")
 	if err != nil {
 		t.Fatal(err)
@@ -145,7 +148,7 @@ func generateReport(t *testing.T, target *targets.Target, test Test) ([]byte, er
 	bin := buildTestBinary(t, target, test, dir)
 	rg, err := MakeReportGenerator(target, bin, dir, dir)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	if test.Result == "" {
 		var pcs []uint64
@@ -175,9 +178,32 @@ func generateReport(t *testing.T, target *targets.Target, test Test) ([]byte, er
 		}
 		test.Progs = append(test.Progs, Prog{Data: "main", PCs: pcs})
 	}
-	out := new(bytes.Buffer)
-	if err := rg.Do(out, test.Progs); err != nil {
-		return nil, err
+	html := new(bytes.Buffer)
+	if err := rg.DoHTML(html, test.Progs); err != nil {
+		return nil, nil, err
+	}
+	csv := new(bytes.Buffer)
+	if err := rg.DoCSV(csv, test.Progs); err != nil {
+		return nil, nil, err
+	}
+
+	return html.Bytes(), csv.Bytes(), nil
+}
+
+func checkCSVReport(t *testing.T, CSVReport []byte) {
+	csvReader := csv.NewReader(bytes.NewBuffer(CSVReport))
+	lines, err := csvReader.ReadAll()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !reflect.DeepEqual(lines[0], CSVHeader) {
+		t.Fatalf("Heading line in CSV doesn't match %v", lines[0])
+	}
+
+	for _, line := range lines {
+		if line[1] == "main" && line[2] != "1" && line[3] != "1" {
+			t.Fatalf("Function coverage percentage doesn't match %v vs. %v", line[2], "100")
+		}
 	}
-	return out.Bytes(), nil
 }