pkg/covermerger: stream information about covered functions to dashboard

3 files changed, 94 insertions, 7 deletions

diff --git a/pkg/coveragedb/coveragedb.go b/pkg/coveragedb/coveragedb.go
index 0692bc131..f2c1cdd69 100644
--- a/pkg/coveragedb/coveragedb.go
+++ b/pkg/coveragedb/coveragedb.go
@@ -71,6 +71,19 @@ type MergedCoverageRecord struct {
 	FileData *Coverage
 }
 
+// FuncLines represents the 'functions' table records.
+// It could be used to maps 'hitcounts' from 'files' table to the function names.
+type FuncLines struct {
+	FilePath string
+	FuncName string
+	Lines    []int64 // List of lines we know belong to this function name according to the addr2line output.
+}
+
+type JSONLWrapper struct {
+	MCR *MergedCoverageRecord
+	FL  *FuncLines
+}
+
 func SaveMergeResult(ctx context.Context, client spannerclient.SpannerClient, descr *HistoryRecord, dec *json.Decoder,
 	sss []*subsystem.Subsystem) (int, error) {
 	if client == nil {
diff --git a/pkg/covermerger/covermerger.go b/pkg/covermerger/covermerger.go
index 34b534593..82ebe1766 100644
--- a/pkg/covermerger/covermerger.go
+++ b/pkg/covermerger/covermerger.go
@@ -22,9 +22,9 @@ import (
 
 const (
 	KeyKernelRepo   = "kernel_repo"
-	KeyKernelBranch = "kernel_branch"
 	KeyKernelCommit = "kernel_commit"
 	KeyFilePath     = "file_path"
+	KeyFuncName     = "func_name"
 	KeyStartLine    = "sl"
 	KeyHitCount     = "hit_count"
 	KeyManager      = "manager"
@@ -32,6 +32,7 @@ const (
 
 type FileRecord struct {
 	FilePath string
+	FuncName string
 	RepoCommit
 	StartLine int
 	HitCount  int
@@ -82,10 +83,15 @@ func MergeCSVWriteJSONL(config *Config, descr *coveragedb.HistoryRecord, csvRead
 			}
 		}
 		for fileMergeResult := range mergeResults {
-			dashCoverageRecords := mergedCoverageRecords(fileMergeResult)
+			dashCoverageRecords, dashFuncLines := mergedCoverageRecords(fileMergeResult)
 			if encoder != nil {
+				for _, record := range dashFuncLines {
+					if err := encoder.Encode(coveragedb.JSONLWrapper{FL: record}); err != nil {
+						return fmt.Errorf("encoder.Encode(FuncLines): %w", err)
+					}
+				}
 				for _, record := range dashCoverageRecords {
-					if err := encoder.Encode(record); err != nil {
+					if err := encoder.Encode(coveragedb.JSONLWrapper{MCR: record}); err != nil {
 						return fmt.Errorf("encoder.Encode(MergedCoverageRecord): %w", err)
 					}
 				}
@@ -107,22 +113,34 @@ func MergeCSVWriteJSONL(config *Config, descr *coveragedb.HistoryRecord, csvRead
 
 const allManagers = "*"
 
-func mergedCoverageRecords(fmr *FileMergeResult) []*coveragedb.MergedCoverageRecord {
+func mergedCoverageRecords(fmr *FileMergeResult) ([]*coveragedb.MergedCoverageRecord, []*coveragedb.FuncLines) {
 	if !fmr.FileExists {
-		return nil
+		return nil, nil
 	}
 	lines := maps.Keys(fmr.HitCounts)
 	slices.Sort(lines)
 	mgrStat := make(map[string]*coveragedb.Coverage)
 	mgrStat[allManagers] = &coveragedb.Coverage{}
 
+	funcLines := map[string]*coveragedb.FuncLines{}
 	for _, line := range lines {
 		mgrStat[allManagers].AddLineHitCount(line, fmr.HitCounts[line])
 		managerHitCounts := map[string]int64{}
+		var srcFuncs []string
 		for _, lineDetail := range fmr.LineDetails[line] {
+			srcFuncs = append(srcFuncs, lineDetail.FuncName)
 			manager := lineDetail.Manager
 			managerHitCounts[manager] += int64(lineDetail.HitCount)
 		}
+		if funcName := bestFuncName(srcFuncs); funcName != "" {
+			if _, ok := funcLines[funcName]; !ok {
+				funcLines[funcName] = &coveragedb.FuncLines{
+					FilePath: fmr.FilePath,
+					FuncName: funcName,
+				}
+			}
+			funcLines[funcName].Lines = append(funcLines[funcName].Lines, int64(line))
+		}
 		for manager, managerHitCount := range managerHitCounts {
 			if _, ok := mgrStat[manager]; !ok {
 				mgrStat[manager] = &coveragedb.Coverage{}
@@ -139,7 +157,27 @@ func mergedCoverageRecords(fmr *FileMergeResult) []*coveragedb.MergedCoverageRec
 			FileData: managerCoverage,
 		})
 	}
-	return res
+	return res, maps.Values(funcLines)
+}
+
+// bestFuncName selects the most frequent function from the list of candidates.
+// If a function was renamed during the collection period, we have to pick one name to display the coverage.
+//
+// The better alternative is to get the function name from the C code. But it looks more complex for now.
+func bestFuncName(names []string) string {
+	stat := map[string]int{}
+	for _, name := range names {
+		stat[name]++
+	}
+	bestName := ""
+	bestCount := 0
+	for name, count := range stat {
+		if name != "" && count > bestCount {
+			bestName = name
+			bestCount = count
+		}
+	}
+	return bestName
 }
 
 func batchFileData(c *Config, targetFilePath string, records []*FileRecord) (*MergeResult, error) {
@@ -172,6 +210,8 @@ func makeRecord(fields, schema []string) (*FileRecord, error) {
 		switch key {
 		case KeyFilePath:
 			record.FilePath = val
+		case KeyFuncName:
+			record.FuncName = val
 		case KeyKernelRepo:
 			record.Repo = val
 		case KeyKernelCommit:
diff --git a/pkg/covermerger/covermerger_test.go b/pkg/covermerger/covermerger_test.go
index ab2b1efc5..e0d03c9a5 100644
--- a/pkg/covermerger/covermerger_test.go
+++ b/pkg/covermerger/covermerger_test.go
@@ -163,11 +163,12 @@ func TestMergerdCoverageRecords(t *testing.T) {
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			gotRecords := mergedCoverageRecords(test.input)
+			gotRecords, gotFuncs := mergedCoverageRecords(test.input)
 			sort.Slice(gotRecords, func(i, j int) bool {
 				return gotRecords[i].Manager < gotRecords[j].Manager
 			})
 			assert.Equal(t, test.wantRecords, gotRecords, "records are not equal")
+			assert.Equal(t, 0, len(gotFuncs), "no functions expected")
 		})
 	}
 }
@@ -241,6 +242,7 @@ samp_time,1,360,arch,b1,ci-mock,git://repo,master,commit1,change_line.c,func1,3,
 			[
 				{
 					"FilePath":"change_line.c",
+					"FuncName":"func1",
 					"Repo":"git://repo",
 					"Commit":"commit1",
 					"StartLine":3,
@@ -271,6 +273,7 @@ samp_time,1,360,arch,b1,ci-mock,git://repo,master,commit1,add_line.c,func1,2,0,2
 			[
 				{
 					"FilePath":"add_line.c",
+					"FuncName":"func1",
 					"Repo":"git://repo",
 					"Commit":"commit1",
 					"StartLine":2,
@@ -302,6 +305,7 @@ samp_time,1,360,arch,b1,ci-mock,git://repo,master,commit2,not_changed.c,func1,4,
 			[
 				{
 					"FilePath":"not_changed.c",
+					"FuncName":"func1",
 					"Repo":"git://repo",
 					"Commit":"commit1",
 					"StartLine":3,
@@ -313,6 +317,7 @@ samp_time,1,360,arch,b1,ci-mock,git://repo,master,commit2,not_changed.c,func1,4,
 			[
 				{
 					"FilePath":"not_changed.c",
+					"FuncName":"func1",
 					"Repo":"git://repo",
 					"Commit":"commit2",
 					"StartLine":4,
@@ -397,3 +402,32 @@ func testConfig(repo, commit, workdir string) *Config {
 		FileVersProvider: &fileVersProviderMock{Workdir: workdir},
 	}
 }
+
+func TestCheckedFuncName(t *testing.T) {
+	tests := []struct {
+		name  string
+		input []string
+		want  string
+	}{
+		{
+			name: "empty input",
+			want: "",
+		},
+		{
+			name:  "single func",
+			input: []string{"func1", "func1"},
+			want:  "func1",
+		},
+		{
+			name:  "multi names",
+			input: []string{"", "", "", "func2", "func2", "func1", "func"},
+			want:  "func2",
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := bestFuncName(test.input)
+			assert.Equal(t, test.want, got)
+		})
+	}
+}