1 // Copyright 2019 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
16 "golang.org/x/sync/errgroup"
17 "golang.org/x/tools/go/analysis"
18 "golang.org/x/tools/internal/analysisinternal"
19 "golang.org/x/tools/internal/event"
20 "golang.org/x/tools/internal/lsp/debug/tag"
21 "golang.org/x/tools/internal/lsp/source"
22 "golang.org/x/tools/internal/memoize"
23 errors "golang.org/x/xerrors"
26 func (s *snapshot) Analyze(ctx context.Context, id string, analyzers ...*analysis.Analyzer) ([]*source.Error, error) {
27 var roots []*actionHandle
29 for _, a := range analyzers {
30 ah, err := s.actionHandle(ctx, packageID(id), a)
34 roots = append(roots, ah)
37 // Check if the context has been canceled before running the analyses.
42 var results []*source.Error
43 for _, ah := range roots {
44 diagnostics, _, err := ah.analyze(ctx, s)
48 results = append(results, diagnostics...)
53 type actionHandleKey string
55 // An action represents one unit of analysis work: the application of
56 // one analysis to one package. Actions form a DAG, both within a
57 // package (as different analyzers are applied, either in sequence or
58 // parallel), and across packages (as dependencies are analyzed).
59 type actionHandle struct {
60 handle *memoize.Handle
62 analyzer *analysis.Analyzer
66 type actionData struct {
67 diagnostics []*source.Error
69 objectFacts map[objectFactKey]analysis.Fact
70 packageFacts map[packageFactKey]analysis.Fact
74 type objectFactKey struct {
79 type packageFactKey struct {
84 func (s *snapshot) actionHandle(ctx context.Context, id packageID, a *analysis.Analyzer) (*actionHandle, error) {
85 ph := s.getPackage(id, source.ParseFull)
87 return nil, errors.Errorf("no package for %s", id)
89 act := s.getActionHandle(id, ph.mode, a)
94 return nil, errors.Errorf("no key for package %s", id)
96 pkg, err := ph.check(ctx, s)
104 var deps []*actionHandle
105 // Add a dependency on each required analyzers.
106 for _, req := range a.Requires {
107 reqActionHandle, err := s.actionHandle(ctx, id, req)
111 deps = append(deps, reqActionHandle)
114 // TODO(golang/go#35089): Re-enable this when we doesn't use ParseExported
115 // mode for dependencies. In the meantime, disable analysis for dependencies,
116 // since we don't get anything useful out of it.
118 // An analysis that consumes/produces facts
119 // must run on the package's dependencies too.
120 if len(a.FactTypes) > 0 {
121 importIDs := make([]string, 0, len(ph.m.deps))
122 for _, importID := range ph.m.deps {
123 importIDs = append(importIDs, string(importID))
125 sort.Strings(importIDs) // for determinism
126 for _, importID := range importIDs {
127 depActionHandle, err := s.actionHandle(ctx, packageID(importID), a)
131 deps = append(deps, depActionHandle)
136 h := s.generation.Bind(buildActionKey(a, ph), func(ctx context.Context, arg memoize.Arg) interface{} {
137 snapshot := arg.(*snapshot)
138 // Analyze dependencies first.
139 results, err := execAll(ctx, snapshot, deps)
145 return runAnalysis(ctx, snapshot, a, pkg, results)
149 act = s.addActionHandle(act)
153 func (act *actionHandle) analyze(ctx context.Context, snapshot *snapshot) ([]*source.Error, interface{}, error) {
154 d, err := act.handle.Get(ctx, snapshot.generation, snapshot)
158 data, ok := d.(*actionData)
160 return nil, nil, errors.Errorf("unexpected type for %s:%s", act.pkg.ID(), act.analyzer.Name)
163 return nil, nil, errors.Errorf("unexpected nil analysis for %s:%s", act.pkg.ID(), act.analyzer.Name)
165 return data.diagnostics, data.result, data.err
168 func buildActionKey(a *analysis.Analyzer, ph *packageHandle) actionHandleKey {
169 return actionHandleKey(hashContents([]byte(fmt.Sprintf("%p %s", a, string(ph.key)))))
172 func (act *actionHandle) String() string {
173 return fmt.Sprintf("%s@%s", act.analyzer, act.pkg.PkgPath())
176 func execAll(ctx context.Context, snapshot *snapshot, actions []*actionHandle) (map[*actionHandle]*actionData, error) {
178 results := make(map[*actionHandle]*actionData)
180 g, ctx := errgroup.WithContext(ctx)
181 for _, act := range actions {
184 v, err := act.handle.Get(ctx, snapshot.generation, snapshot)
188 data, ok := v.(*actionData)
190 return errors.Errorf("unexpected type for %s: %T", act, v)
200 return results, g.Wait()
203 func runAnalysis(ctx context.Context, snapshot *snapshot, analyzer *analysis.Analyzer, pkg *pkg, deps map[*actionHandle]*actionData) (data *actionData) {
205 objectFacts: make(map[objectFactKey]analysis.Fact),
206 packageFacts: make(map[packageFactKey]analysis.Fact),
209 if r := recover(); r != nil {
210 event.Log(ctx, fmt.Sprintf("analysis panicked: %s", r), tag.Package.Of(pkg.PkgPath()))
211 data.err = errors.Errorf("analysis %s for package %s panicked: %v", analyzer.Name, pkg.PkgPath(), r)
215 // Plumb the output values of the dependencies
216 // into the inputs of this action. Also facts.
217 inputs := make(map[*analysis.Analyzer]interface{})
219 for depHandle, depData := range deps {
220 if depHandle.pkg == pkg {
221 // Same package, different analysis (horizontal edge):
222 // in-memory outputs of prerequisite analyzers
223 // become inputs to this analysis pass.
224 inputs[depHandle.analyzer] = depData.result
225 } else if depHandle.analyzer == analyzer { // (always true)
226 // Same analysis, different package (vertical edge):
227 // serialized facts produced by prerequisite analysis
228 // become available to this analysis pass.
229 for key, fact := range depData.objectFacts {
230 // Filter out facts related to objects
231 // that are irrelevant downstream
232 // (equivalently: not in the compiler export data).
233 if !exportedFrom(key.obj, depHandle.pkg.types) {
236 data.objectFacts[key] = fact
238 for key, fact := range depData.packageFacts {
239 // TODO: filter out facts that belong to
240 // packages not mentioned in the export data
241 // to prevent side channels.
243 data.packageFacts[key] = fact
248 var syntax []*ast.File
249 for _, cgf := range pkg.compiledGoFiles {
250 syntax = append(syntax, cgf.File)
253 var diagnostics []*analysis.Diagnostic
256 pass := &analysis.Pass{
258 Fset: snapshot.view.session.cache.fset,
261 TypesInfo: pkg.GetTypesInfo(),
262 TypesSizes: pkg.GetTypesSizes(),
264 Report: func(d analysis.Diagnostic) {
265 // Prefix the diagnostic category with the analyzer's name.
266 if d.Category == "" {
267 d.Category = analyzer.Name
269 d.Category = analyzer.Name + "." + d.Category
271 diagnostics = append(diagnostics, &d)
273 ImportObjectFact: func(obj types.Object, ptr analysis.Fact) bool {
277 key := objectFactKey{obj, factType(ptr)}
279 if v, ok := data.objectFacts[key]; ok {
280 reflect.ValueOf(ptr).Elem().Set(reflect.ValueOf(v).Elem())
285 ExportObjectFact: func(obj types.Object, fact analysis.Fact) {
286 if obj.Pkg() != pkg.types {
287 panic(fmt.Sprintf("internal error: in analysis %s of package %s: Fact.Set(%s, %T): can't set facts on objects belonging another package",
288 analyzer, pkg.ID(), obj, fact))
290 key := objectFactKey{obj, factType(fact)}
291 data.objectFacts[key] = fact // clobber any existing entry
293 ImportPackageFact: func(pkg *types.Package, ptr analysis.Fact) bool {
297 key := packageFactKey{pkg, factType(ptr)}
298 if v, ok := data.packageFacts[key]; ok {
299 reflect.ValueOf(ptr).Elem().Set(reflect.ValueOf(v).Elem())
304 ExportPackageFact: func(fact analysis.Fact) {
305 key := packageFactKey{pkg.types, factType(fact)}
306 data.packageFacts[key] = fact // clobber any existing entry
308 AllObjectFacts: func() []analysis.ObjectFact {
309 facts := make([]analysis.ObjectFact, 0, len(data.objectFacts))
310 for k := range data.objectFacts {
311 facts = append(facts, analysis.ObjectFact{Object: k.obj, Fact: data.objectFacts[k]})
315 AllPackageFacts: func() []analysis.PackageFact {
316 facts := make([]analysis.PackageFact, 0, len(data.packageFacts))
317 for k := range data.packageFacts {
318 facts = append(facts, analysis.PackageFact{Package: k.pkg, Fact: data.packageFacts[k]})
323 analysisinternal.SetTypeErrors(pass, pkg.typeErrors)
325 if pkg.IsIllTyped() {
326 data.err = errors.Errorf("analysis skipped due to errors in package: %v", pkg.GetErrors())
329 data.result, data.err = pass.Analyzer.Run(pass)
334 if got, want := reflect.TypeOf(data.result), pass.Analyzer.ResultType; got != want {
335 data.err = errors.Errorf(
336 "internal error: on package %s, analyzer %s returned a result of type %v, but declared ResultType %v",
337 pass.Pkg.Path(), pass.Analyzer, got, want)
341 // disallow calls after Run
342 pass.ExportObjectFact = func(obj types.Object, fact analysis.Fact) {
343 panic(fmt.Sprintf("%s:%s: Pass.ExportObjectFact(%s, %T) called after Run", analyzer.Name, pkg.PkgPath(), obj, fact))
345 pass.ExportPackageFact = func(fact analysis.Fact) {
346 panic(fmt.Sprintf("%s:%s: Pass.ExportPackageFact(%T) called after Run", analyzer.Name, pkg.PkgPath(), fact))
349 for _, diag := range diagnostics {
350 srcErr, err := sourceError(ctx, snapshot, pkg, diag)
352 event.Error(ctx, "unable to compute analysis error position", err, tag.Category.Of(diag.Category), tag.Package.Of(pkg.ID()))
355 if ctx.Err() != nil {
359 data.diagnostics = append(data.diagnostics, srcErr)
364 // exportedFrom reports whether obj may be visible to a package that imports pkg.
365 // This includes not just the exported members of pkg, but also unexported
366 // constants, types, fields, and methods, perhaps belonging to oether packages,
367 // that find there way into the API.
368 // This is an overapproximation of the more accurate approach used by
369 // gc export data, which walks the type graph, but it's much simpler.
371 // TODO(adonovan): do more accurate filtering by walking the type graph.
372 func exportedFrom(obj types.Object, pkg *types.Package) bool {
373 switch obj := obj.(type) {
375 return obj.Exported() && obj.Pkg() == pkg ||
376 obj.Type().(*types.Signature).Recv() != nil
378 return obj.Exported() && obj.Pkg() == pkg ||
380 case *types.TypeName, *types.Const:
383 return false // Nil, Builtin, Label, or PkgName
386 func factType(fact analysis.Fact) reflect.Type {
387 t := reflect.TypeOf(fact)
388 if t.Kind() != reflect.Ptr {
389 panic(fmt.Sprintf("invalid Fact type: got %T, want pointer", t))