diff --git a/client/llb/source.go b/client/llb/source.go
index 0767dce42..a59a11312 100644
--- a/client/llb/source.go
+++ b/client/llb/source.go
@@ -196,6 +196,9 @@ func Local(name string, opts ...LocalOption) State {
 	if gi.ExcludePatterns != "" {
 		attrs[pb.AttrExcludePatterns] = gi.ExcludePatterns
 	}
+	if gi.SharedKeyHint != "" {
+		attrs[pb.AttrSharedKeyHint] = gi.SharedKeyHint
+	}
 
 	source := NewSource("local://"+name, attrs, gi.Metadata())
 	return NewState(source.Output())
@@ -239,11 +242,18 @@ func ExcludePatterns(p []string) LocalOption {
 	})
 }
 
+func SharedKeyHint(h string) LocalOption {
+	return localOptionFunc(func(li *LocalInfo) {
+		li.SharedKeyHint = h
+	})
+}
+
 type LocalInfo struct {
 	opMetaWrapper
 	SessionID       string
 	IncludePatterns string
 	ExcludePatterns string
+	SharedKeyHint   string
 }
 
 func HTTP(url string, opts ...HTTPOption) State {
diff --git a/client/local.go b/client/local.go
deleted file mode 100644
index 25c977079..000000000
--- a/client/local.go
+++ /dev/null
@@ -1,5 +0,0 @@
-package client
-
-func getSharedKey(dir string) (string, error) {
-	return dir, nil // not implemented
-}
diff --git a/frontend/dockerfile/builder/build.go b/frontend/dockerfile/builder/build.go
index cc3031805..60d30c58e 100644
--- a/frontend/dockerfile/builder/build.go
+++ b/frontend/dockerfile/builder/build.go
@@ -41,6 +41,7 @@ func Build(ctx context.Context, c client.Client) error {
 	src := llb.Local(LocalNameDockerfile,
 		llb.IncludePatterns([]string{filename}),
 		llb.SessionID(c.SessionID()),
+		llb.SharedKeyHint(defaultDockerfileName),
 	)
 	var buildContext *llb.State
 	if strings.HasPrefix(opts[LocalNameContext], gitPrefix) {
@@ -70,7 +71,11 @@ func Build(ctx context.Context, c client.Client) error {
 	eg.Go(func() error {
 		dockerignoreState := buildContext
 		if dockerignoreState == nil {
-			st := llb.Local(LocalNameContext, llb.SessionID(c.SessionID()), llb.IncludePatterns([]string{dockerignoreFilename}))
+			st := llb.Local(LocalNameContext,
+				llb.SessionID(c.SessionID()),
+				llb.IncludePatterns([]string{dockerignoreFilename}),
+				llb.SharedKeyHint(dockerignoreFilename),
+			)
 			dockerignoreState = &st
 		}
 		def, err := dockerignoreState.Marshal()
diff --git a/frontend/dockerfile/dockerfile2llb/convert.go b/frontend/dockerfile/dockerfile2llb/convert.go
index 878cf8e81..3252de203 100644
--- a/frontend/dockerfile/dockerfile2llb/convert.go
+++ b/frontend/dockerfile/dockerfile2llb/convert.go
@@ -167,7 +167,11 @@ func Dockerfile2LLB(ctx context.Context, dt []byte, opt ConvertOpt) (*llb.State,
 	if err := eg.Wait(); err != nil {
 		return nil, nil, err
 	}
-	buildContext := llb.Local(localNameContext, llb.SessionID(opt.SessionID), llb.ExcludePatterns(opt.Excludes))
+	buildContext := llb.Local(localNameContext,
+		llb.SessionID(opt.SessionID),
+		llb.ExcludePatterns(opt.Excludes),
+		llb.SharedKeyHint(localNameContext),
+	)
 	if opt.BuildContext != nil {
 		buildContext = *opt.BuildContext
 	}
diff --git a/solver/pb/attr.go b/solver/pb/attr.go
index f507a2529..631c16610 100644
--- a/solver/pb/attr.go
+++ b/solver/pb/attr.go
@@ -4,6 +4,7 @@ const AttrKeepGitDir = "git.keepgitdir"
 const AttrLocalSessionID = "local.session"
 const AttrIncludePatterns = "local.includepattern"
 const AttrExcludePatterns = "local.excludepatterns"
+const AttrSharedKeyHint = "local.sharedkeyhint"
 const AttrLLBDefinitionFilename = "llbbuild.filename"
 
 const AttrHTTPChecksum = "http.checksum"
diff --git a/source/identifier.go b/source/identifier.go
index 59ff0cb02..a5356de6f 100644
--- a/source/identifier.go
+++ b/source/identifier.go
@@ -86,6 +86,8 @@ func FromLLB(op *pb.Op_Source) (Identifier, error) {
 					return nil, err
 				}
 				id.ExcludePatterns = patterns
+			case pb.AttrSharedKeyHint:
+				id.SharedKeyHint = v
 			}
 		}
 	}
@@ -149,6 +151,7 @@ type LocalIdentifier struct {
 	SessionID       string
 	IncludePatterns []string
 	ExcludePatterns []string
+	SharedKeyHint   string
 }
 
 func NewLocalIdentifier(str string) (*LocalIdentifier, error) {
diff --git a/source/local/local.go b/source/local/local.go
index 3565f8ecd..34f20bd5a 100644
--- a/source/local/local.go
+++ b/source/local/local.go
@@ -79,7 +79,8 @@ func (ls *localSourceHandler) CacheKey(ctx context.Context) (string, error) {
 	dt, err := json.Marshal(struct {
 		SessionID       string
 		IncludePatterns []string
-	}{SessionID: sessionID, IncludePatterns: ls.src.IncludePatterns})
+		ExcludePatterns []string
+	}{SessionID: sessionID, IncludePatterns: ls.src.IncludePatterns, ExcludePatterns: ls.src.ExcludePatterns})
 	if err != nil {
 		return "", err
 	}
@@ -101,7 +102,7 @@ func (ls *localSourceHandler) Snapshot(ctx context.Context) (out cache.Immutable
 		return nil, err
 	}
 
-	sharedKey := keySharedKey + ":" + ls.src.Name + ":" + caller.SharedKey()
+	sharedKey := keySharedKey + ":" + ls.src.Name + ":" + ls.src.SharedKeyHint + ":" + caller.SharedKey() // TODO: replace caller.SharedKey() with source based hint from client(absolute-path+nodeid)
 
 	var mutable cache.MutableRef
 	sis, err := ls.md.Search(sharedKey)