internal/vulncheck: load source code for scan symbol mode only

For package and module scan mode, loading code is not needed and it just
takes longer. With this CL, the loading for these mode drops down by
~40%.

Change-Id: Ibdaa98c50e3e90ba1696d8b9706589ff4c279e17
Reviewed-on: https://go-review.googlesource.com/c/vuln/+/585335
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Cottrell <iancottrell@google.com>
Run-TryBot: Zvonimir Pavlinovic <zpavlinovic@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

Author: zpavlinovic

internal/scan/source.go

@@ -35,7 +35,7 @@ func runSource(ctx context.Context, handler govulncheck.Handler, cfg *config, cl
 		Tests: cfg.test,
 		Env:   cfg.env,
 	}
-	if err := graph.LoadPackagesAndMods(pkgConfig, cfg.tags, cfg.patterns); err != nil {
+	if err := graph.LoadPackagesAndMods(pkgConfig, cfg.tags, cfg.patterns, cfg.ScanLevel == govulncheck.ScanLevelSymbol); err != nil {
 		if isGoVersionMismatchError(err) {
 			return fmt.Errorf("%v\n\n%v", errGoVersionMismatch, err)
 		}

internal/vulncheck/packages.go

@@ -194,18 +194,12 @@ func (g *PackageGraph) GetPackage(path string) *packages.Package {
 
 // LoadPackages loads the packages specified by the patterns into the graph.
 // See golang.org/x/tools/go/packages.Load for details of how it works.
-func (g *PackageGraph) LoadPackagesAndMods(cfg *packages.Config, tags []string, patterns []string) error {
+func (g *PackageGraph) LoadPackagesAndMods(cfg *packages.Config, tags []string, patterns []string, wantSymbols bool) error {
 	if len(tags) > 0 {
 		cfg.BuildFlags = []string{fmt.Sprintf("-tags=%s", strings.Join(tags, ","))}
 	}
-	cfg.Mode |=
-		packages.NeedDeps |
-			packages.NeedImports |
-			packages.NeedModule |
-			packages.NeedSyntax |
-			packages.NeedTypes |
-			packages.NeedTypesInfo |
-			packages.NeedName
+
+	addLoadMode(cfg, wantSymbols)
 
 	pkgs, err := packages.Load(cfg, patterns...)
 	if err != nil {
@@ -230,6 +224,17 @@ func (g *PackageGraph) LoadPackagesAndMods(cfg *packages.Config, tags []string,
 	return err
 }
 
+func addLoadMode(cfg *packages.Config, wantSymbols bool) {
+	cfg.Mode |=
+		packages.NeedModule |
+			packages.NeedName |
+			packages.NeedDeps |
+			packages.NeedImports
+	if wantSymbols {
+		cfg.Mode |= packages.NeedSyntax | packages.NeedTypes | packages.NeedTypesInfo
+	}
+}
+
 // packageError contains errors from loading a set of packages.
 type packageError struct {
 	Errors []packages.Error

internal/vulncheck/slicing_test.go

@@ -91,7 +91,7 @@ func Do(i I, input string) {
 	})
 
 	graph := NewPackageGraph("go1.18")
-	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "/module/slice")})
+	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "/module/slice")}, true)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/vulncheck/source_test.go

@@ -191,7 +191,7 @@ func TestCalls(t *testing.T) {
 
 	// Load x and y as entry packages.
 	graph := NewPackageGraph("go1.18")
-	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x"), path.Join(e.Temp(), "entry/y")})
+	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x"), path.Join(e.Temp(), "entry/y")}, true)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -298,7 +298,7 @@ func TestAllSymbolsVulnerable(t *testing.T) {
 
 	// Load x as entry package.
 	graph := NewPackageGraph("go1.18")
-	err = graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")})
+	err = graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")}, true)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -361,7 +361,7 @@ func TestNoSyntheticNodes(t *testing.T) {
 
 	// Load x as entry package.
 	graph := NewPackageGraph("go1.18")
-	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")})
+	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")}, true)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -435,7 +435,7 @@ func TestRecursion(t *testing.T) {
 
 	// Load x as entry package.
 	graph := NewPackageGraph("go1.18")
-	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")})
+	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")}, true)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -500,7 +500,7 @@ func TestIssue57174(t *testing.T) {
 
 	// Load x as entry package.
 	graph := NewPackageGraph("go1.18")
-	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")})
+	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")}, true)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/vulncheck/utils_test.go

@@ -228,7 +228,7 @@ func TestDbSymbolName(t *testing.T) {
 	defer e.Cleanup()
 
 	graph := NewPackageGraph("go1.18")
-	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "package/x")})
+	err := graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "package/x")}, true)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/vulncheck/witness_test.go

@@ -182,7 +182,7 @@ func TestInits(t *testing.T) {
 
 	// Load x as entry package.
 	graph := NewPackageGraph("go1.18")
-	err = graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")})
+	err = graph.LoadPackagesAndMods(e.Config, nil, []string{path.Join(e.Temp(), "entry/x")}, true)
 	if err != nil {
 		t.Fatal(err)
 	}