diff --git a/java/base.go b/java/base.go
index fe92b47..e38f0b9 100644
--- a/java/base.go
+++ b/java/base.go
@@ -820,7 +820,7 @@
 }
 
 func (j *Module) aidlFlags(ctx android.ModuleContext, aidlPreprocess android.OptionalPath,
-	aidlIncludeDirs android.Paths) (string, android.Paths) {
+	aidlIncludeDirs android.Paths, aidlSrcs android.Paths) (string, android.Paths) {
 
 	aidlIncludes := android.PathsForModuleSrc(ctx, j.deviceProperties.Aidl.Local_include_dirs)
 	aidlIncludes = append(aidlIncludes,
@@ -830,6 +830,7 @@
 
 	var flags []string
 	var deps android.Paths
+	var includeDirs android.Paths
 
 	flags = append(flags, j.deviceProperties.Aidl.Flags...)
 
@@ -837,21 +838,24 @@
 		flags = append(flags, "-p"+aidlPreprocess.String())
 		deps = append(deps, aidlPreprocess.Path())
 	} else if len(aidlIncludeDirs) > 0 {
-		flags = append(flags, android.JoinWithPrefix(aidlIncludeDirs.Strings(), "-I"))
+		includeDirs = append(includeDirs, aidlIncludeDirs...)
 	}
 
 	if len(j.exportAidlIncludeDirs) > 0 {
-		flags = append(flags, android.JoinWithPrefix(j.exportAidlIncludeDirs.Strings(), "-I"))
+		includeDirs = append(includeDirs, j.exportAidlIncludeDirs...)
 	}
 
 	if len(aidlIncludes) > 0 {
-		flags = append(flags, android.JoinWithPrefix(aidlIncludes.Strings(), "-I"))
+		includeDirs = append(includeDirs, aidlIncludes...)
 	}
 
-	flags = append(flags, "-I"+android.PathForModuleSrc(ctx).String())
+	includeDirs = append(includeDirs, android.PathForModuleSrc(ctx))
 	if src := android.ExistentPathForSource(ctx, ctx.ModuleDir(), "src"); src.Valid() {
-		flags = append(flags, "-I"+src.String())
+		includeDirs = append(includeDirs, src.Path())
 	}
+	flags = append(flags, android.JoinWithPrefix(includeDirs.Strings(), "-I"))
+	// add flags for dirs containing AIDL srcs that haven't been specified yet
+	flags = append(flags, genAidlIncludeFlags(ctx, aidlSrcs, includeDirs))
 
 	if Bool(j.deviceProperties.Aidl.Generate_traces) {
 		flags = append(flags, "-t")
@@ -935,9 +939,6 @@
 	// systemModules
 	flags.systemModules = deps.systemModules
 
-	// aidl flags.
-	flags.aidlFlags, flags.aidlDeps = j.aidlFlags(ctx, deps.aidlPreprocess, deps.aidlIncludeDirs)
-
 	return flags
 }
 
@@ -1046,6 +1047,9 @@
 		ctx.PropertyErrorf("common_srcs", "common_srcs must be .kt files")
 	}
 
+	aidlSrcs := srcFiles.FilterByExt(".aidl")
+	flags.aidlFlags, flags.aidlDeps = j.aidlFlags(ctx, deps.aidlPreprocess, deps.aidlIncludeDirs, aidlSrcs)
+
 	nonGeneratedSrcJars := srcFiles.FilterByExt(".srcjar")
 	srcFiles = j.genSources(ctx, srcFiles, flags)
 
diff --git a/java/droiddoc.go b/java/droiddoc.go
index 901419c..9b1f43b 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -314,7 +314,7 @@
 	outSrcFiles := make(android.Paths, 0, len(srcFiles))
 	var aidlSrcs android.Paths
 
-	aidlIncludeFlags := genAidlIncludeFlags(srcFiles)
+	aidlIncludeFlags := genAidlIncludeFlags(ctx, srcFiles, android.Paths{})
 
 	for _, srcFile := range srcFiles {
 		switch srcFile.Ext() {
diff --git a/java/gen.go b/java/gen.go
index 1572bf0..638da25 100644
--- a/java/gen.go
+++ b/java/gen.go
@@ -15,6 +15,7 @@
 package java
 
 import (
+	"path/filepath"
 	"strconv"
 	"strings"
 
@@ -116,12 +117,31 @@
 	return javaFile
 }
 
-func genAidlIncludeFlags(srcFiles android.Paths) string {
+// genAidlIncludeFlags returns additional include flags based on the relative path
+// of each .aidl file passed in srcFiles. excludeDirs is a list of paths relative to
+// the Android checkout root that should not be included in the returned flags.
+func genAidlIncludeFlags(ctx android.PathContext, srcFiles android.Paths, excludeDirs android.Paths) string {
 	var baseDirs []string
+	excludeDirsStrings := excludeDirs.Strings()
 	for _, srcFile := range srcFiles {
 		if srcFile.Ext() == ".aidl" {
 			baseDir := strings.TrimSuffix(srcFile.String(), srcFile.Rel())
-			if baseDir != "" && !android.InList(baseDir, baseDirs) {
+			baseDir = filepath.Clean(baseDir)
+			baseDirSeen := android.InList(baseDir, baseDirs) || android.InList(baseDir, excludeDirsStrings)
+
+			// For go/bp2build mixed builds, a file may be listed under a
+			// directory in the Bazel output tree that is symlinked to a
+			// directory under the android source tree. We should only
+			// include one copy of this directory so that the AIDL tool
+			// doesn't find multiple definitions of the same AIDL class.
+			// This code comes into effect when filegroups are used in mixed builds.
+			bazelPathPrefix := android.PathForBazelOut(ctx, "").String()
+			bazelBaseDir, err := filepath.Rel(bazelPathPrefix, baseDir)
+			bazelBaseDirSeen := err == nil &&
+				android.InList(bazelBaseDir, baseDirs) ||
+				android.InList(bazelBaseDir, excludeDirsStrings)
+
+			if baseDir != "" && !baseDirSeen && !bazelBaseDirSeen {
 				baseDirs = append(baseDirs, baseDir)
 			}
 		}
@@ -136,8 +156,6 @@
 	var protoSrcs android.Paths
 	var aidlSrcs android.Paths
 
-	aidlIncludeFlags := genAidlIncludeFlags(srcFiles)
-
 	for _, srcFile := range srcFiles {
 		switch srcFile.Ext() {
 		case ".aidl":
@@ -168,7 +186,7 @@
 				individualFlags[aidlSrc.String()] = flags
 			}
 		}
-		srcJarFiles := genAidl(ctx, aidlSrcs, flags.aidlFlags+aidlIncludeFlags, individualFlags, flags.aidlDeps)
+		srcJarFiles := genAidl(ctx, aidlSrcs, flags.aidlFlags, individualFlags, flags.aidlDeps)
 		outSrcFiles = append(outSrcFiles, srcJarFiles...)
 	}
 
diff --git a/java/java_test.go b/java/java_test.go
index bfd97eb..7f0cea7 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -1747,3 +1747,37 @@
 	android.AssertDeepEquals(t, "Implementation/Resources JARs are produced", expectedOutputFiles, android.NormalizePathsForTesting(javaInfo.ImplementationAndResourcesJars))
 	android.AssertDeepEquals(t, "Implementation JARs are produced", expectedOutputFiles, android.NormalizePathsForTesting(javaInfo.ImplementationJars))
 }
+
+func TestGenAidlIncludeFlagsForMixedBuilds(t *testing.T) {
+	bazelOutputBaseDir := filepath.Join("out", "bazel")
+	result := android.GroupFixturePreparers(
+		PrepareForIntegrationTestWithJava,
+		android.FixtureModifyConfig(func(config android.Config) {
+			config.BazelContext = android.MockBazelContext{
+				OutputBaseDir: bazelOutputBaseDir,
+			}
+		}),
+	).RunTest(t)
+
+	ctx := &android.TestPathContext{TestResult: result}
+
+	srcDirectory := filepath.Join("frameworks", "base")
+	srcDirectoryAlreadyIncluded := filepath.Join("frameworks", "base", "core", "java")
+	bazelSrcDirectory := android.PathForBazelOut(ctx, srcDirectory)
+	bazelSrcDirectoryAlreadyIncluded := android.PathForBazelOut(ctx, srcDirectoryAlreadyIncluded)
+	srcs := android.Paths{
+		android.PathForTestingWithRel(bazelSrcDirectory.String(), "bazelAidl.aidl"),
+		android.PathForTestingWithRel(bazelSrcDirectory.String(), "bazelAidl2.aidl"),
+		android.PathForTestingWithRel(bazelSrcDirectoryAlreadyIncluded.String(), "bazelAidlExclude.aidl"),
+		android.PathForTestingWithRel(bazelSrcDirectoryAlreadyIncluded.String(), "bazelAidl2Exclude.aidl"),
+	}
+	dirsAlreadyIncluded := android.Paths{
+		android.PathForTesting(srcDirectoryAlreadyIncluded),
+	}
+
+	expectedFlags := " -Iout/bazel/execroot/__main__/frameworks/base"
+	flags := genAidlIncludeFlags(ctx, srcs, dirsAlreadyIncluded)
+	if flags != expectedFlags {
+		t.Errorf("expected flags to be %q; was %q", expectedFlags, flags)
+	}
+}