internal/lsp: add analyses to the snapshot

This change makes sure that actionHandles are cached within the
snapshot, to minimize the cost of re-computing action handles on each
run of go/analysis.

Change-Id: If6191c5224285eb207aebb997787ea551a47fbaa
Reviewed-on: https://go-review.googlesource.com/c/tools/+/201098
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>

internal/lsp/cache/analysis.go

@@ -17,6 +17,11 @@ import (
 	errors "golang.org/x/xerrors"
 )
 
+type actionKey struct {
+	pkg      packageKey
+	analyzer string // analyzer name
+}
+
 func (s *snapshot) Analyze(ctx context.Context, id string, analyzers []*analysis.Analyzer) (map[*analysis.Analyzer][]*analysis.Diagnostic, error) {
 	var roots []*actionHandle
 
@@ -79,6 +84,10 @@ type packageFactKey struct {
 }
 
 func (s *snapshot) actionHandle(ctx context.Context, id packageID, mode source.ParseMode, a *analysis.Analyzer) (*actionHandle, error) {
+	ah := s.getAction(id, mode, a.Name)
+	if ah != nil {
+		return ah, nil
+	}
 	cph := s.getPackage(id, mode)
 	if cph == nil {
 		return nil, errors.Errorf("no CheckPackageHandle for %s:%v", id, mode == source.ParseExported)
@@ -90,7 +99,7 @@ func (s *snapshot) actionHandle(ctx context.Context, id packageID, mode source.P
 	if err != nil {
 		return nil, err
 	}
-	ah := &actionHandle{
+	ah = &actionHandle{
 		analyzer: a,
 		pkg:      pkg,
 	}
@@ -118,12 +127,13 @@ func (s *snapshot) actionHandle(ctx context.Context, id packageID, mode source.P
 			ah.deps = append(ah.deps, depActionHandle)
 		}
 	}
-	h := s.view.session.cache.store.Bind(actionKey(a, cph), func(ctx context.Context) interface{} {
+	h := s.view.session.cache.store.Bind(buildActionKey(a, cph), func(ctx context.Context) interface{} {
 		data := &actionData{}
 		data.diagnostics, data.result, data.err = ah.exec(ctx, s.view.session.cache.fset)
 		return data
 	})
 	ah.handle = h
+	s.addAction(ah)
 	return ah, nil
 }
 
@@ -136,7 +146,7 @@ func (ah *actionHandle) analyze(ctx context.Context) ([]*analysis.Diagnostic, in
 	return data.diagnostics, data.result, data.err
 }
 
-func actionKey(a *analysis.Analyzer, cph *checkPackageHandle) string {
+func buildActionKey(a *analysis.Analyzer, cph *checkPackageHandle) string {
 	return hashContents([]byte(fmt.Sprintf("%s %s", a, string(cph.key))))
 }
 

internal/lsp/cache/check.go

@@ -266,6 +266,7 @@ func (imp *importer) typeCheck(ctx context.Context, cph *checkPackageHandle) (*p
 	pkg := &pkg{
 		view:       imp.snapshot.view,
 		id:         cph.m.id,
+		mode:       cph.mode,
 		pkgPath:    cph.m.pkgPath,
 		files:      cph.Files(),
 		imports:    make(map[packagePath]*pkg),

internal/lsp/cache/pkg.go

@@ -24,6 +24,7 @@ type pkg struct {
 
 	// ID and package path have their own types to avoid being used interchangeably.
 	id         packageID
+	mode       source.ParseMode
 	pkgPath    packagePath
 	files      []source.ParseGoHandle
 	errors     []packages.Error

internal/lsp/cache/session.go

@@ -104,6 +104,7 @@ func (s *session) NewView(ctx context.Context, name string, folder span.URI, opt
 			metadata:   make(map[packageID]*metadata),
 			files:      make(map[span.URI]source.FileHandle),
 			importedBy: make(map[packageID][]packageID),
+			actions:    make(map[actionKey]*actionHandle),
 		},
 		ignoredURIs: make(map[span.URI]struct{}),
 		builtin:     &builtinPkg{},

internal/lsp/cache/snapshot.go

@@ -29,9 +29,12 @@ type snapshot struct {
 	// It may invalidated when a file's content changes.
 	files map[span.URI]source.FileHandle
 
-	// packages maps a file URI to a set of CheckPackageHandles to which that file belongs.
+	// packages maps a packageKey to a set of CheckPackageHandles to which that file belongs.
 	// It may be invalidated when a file's content changes.
 	packages map[packageKey]*checkPackageHandle
+
+	// actions maps an actionkey to its actionHandle.
+	actions map[actionKey]*actionHandle
 }
 
 func (s *snapshot) View() source.View {
@@ -93,6 +96,37 @@ func (s *snapshot) getPackage(id packageID, m source.ParseMode) *checkPackageHan
 	return s.packages[key]
 }
 
+func (s *snapshot) getAction(id packageID, m source.ParseMode, analyzer string) *actionHandle {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	key := actionKey{
+		pkg: packageKey{
+			id:   id,
+			mode: m,
+		},
+		analyzer: analyzer,
+	}
+	return s.actions[key]
+}
+
+func (s *snapshot) addAction(ah *actionHandle) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	key := actionKey{
+		analyzer: ah.analyzer.Name,
+		pkg: packageKey{
+			id:   ah.pkg.id,
+			mode: ah.pkg.mode,
+		},
+	}
+	if _, ok := s.actions[key]; ok {
+		return
+	}
+	s.actions[key] = ah
+}
+
 func (s *snapshot) getMetadataForURI(uri span.URI) (metadata []*metadata) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -175,6 +209,7 @@ func (s *snapshot) clone(ctx context.Context, withoutURI *span.URI, withoutTypes
 		importedBy: make(map[packageID][]packageID),
 		metadata:   make(map[packageID]*metadata),
 		packages:   make(map[packageKey]*checkPackageHandle),
+		actions:    make(map[actionKey]*actionHandle),
 		files:      make(map[span.URI]source.FileHandle),
 	}
 	// Copy all of the FileHandles except for the one that was invalidated.
@@ -216,6 +251,16 @@ func (s *snapshot) clone(ctx context.Context, withoutURI *span.URI, withoutTypes
 		}
 		result.packages[k] = v
 	}
+	// Copy the package analysis information.
+	for k, v := range s.actions {
+		if _, ok := withoutTypesIDs[k.pkg.id]; ok {
+			continue
+		}
+		if _, ok := withoutMetadataIDs[k.pkg.id]; ok {
+			continue
+		}
+		result.actions[k] = v
+	}
 	// Copy the package metadata.
 	for k, v := range s.metadata {
 		if _, ok := withoutMetadataIDs[k]; ok {