Merge changes from topic "lint-update-7.1.0"

* changes:
  Downgrade new errors from lint 7.1.0-dev to warnings
  Filter srcjars out of srcFiles
diff --git a/Android.bp b/Android.bp
index 45e661e..d6260b4 100644
--- a/Android.bp
+++ b/Android.bp
@@ -116,3 +116,13 @@
 dex_bootjars {
     name: "dex_bootjars",
 }
+
+// Pseudo-test that's run on checkbuilds to ensure that get_clang_version can
+// parse cc/config/global.go.
+genrule {
+    name: "get_clang_version_test",
+    cmd: "$(location get_clang_version) > $(out)",
+    tools: ["get_clang_version"],
+    srcs: ["cc/config/global.go"],
+    out: ["clang-prebuilts-version.txt"],
+}
diff --git a/README.md b/README.md
index b7e93f4..10ddd73 100644
--- a/README.md
+++ b/README.md
@@ -213,8 +213,8 @@
 
 A module name's **scope** is the smallest namespace containing it. Suppose a
 source tree has `device/my` and `device/my/display` namespaces. If `libfoo`
-module is defined in `device/co/display/lib/Android.bp`, its namespace is
-`device/co/display`.
+module is defined in `device/my/display/lib/Android.bp`, its namespace is
+`device/my/display`.
 
 The name uniqueness thus means that module's name is unique within its scope. In
 other words, "//_scope_:_name_" is globally unique module reference, e.g,
diff --git a/apex/prebuilt.go b/apex/prebuilt.go
index f783172..1bb0fb5 100644
--- a/apex/prebuilt.go
+++ b/apex/prebuilt.go
@@ -376,6 +376,12 @@
 			}
 		}
 
+		// Ignore any modules that do not implement ApexModule as they cannot have an APEX specific
+		// variant.
+		if _, ok := child.(android.ApexModule); !ok {
+			return false
+		}
+
 		// Strip off the prebuilt_ prefix if present before storing content to ensure consistent
 		// behavior whether there is a corresponding source module present or not.
 		depName = android.RemoveOptionalPrebuiltPrefix(depName)
diff --git a/cc/cc_test.go b/cc/cc_test.go
index 401fd6f..0a74e58 100644
--- a/cc/cc_test.go
+++ b/cc/cc_test.go
@@ -4046,12 +4046,12 @@
 		"${config.ArmToolchainClangCflags}",
 		"${config.ArmClangArmv7ANeonCflags}",
 		"${config.ArmClangGenericCflags}",
-		"export_include_dirs",
-		"linux_export_include_dirs",
-		"android_export_include_dirs",
-		"arm_export_include_dirs",
-		"lib32_export_include_dirs",
 		"android_arm_export_include_dirs",
+		"lib32_export_include_dirs",
+		"arm_export_include_dirs",
+		"android_export_include_dirs",
+		"linux_export_include_dirs",
+		"export_include_dirs",
 		"android_arm_local_include_dirs",
 		"lib32_local_include_dirs",
 		"arm_local_include_dirs",
diff --git a/cc/compiler.go b/cc/compiler.go
index 78a5a5d..69ead30 100644
--- a/cc/compiler.go
+++ b/cc/compiler.go
@@ -92,7 +92,7 @@
 
 	// list of generated headers to add to the include path. These are the names
 	// of genrule modules.
-	Generated_headers []string `android:"arch_variant"`
+	Generated_headers []string `android:"arch_variant,variant_prepend"`
 
 	// pass -frtti instead of -fno-rtti
 	Rtti *bool
diff --git a/cc/library.go b/cc/library.go
index 95f9b0a..684694b 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -184,11 +184,11 @@
 	// be added to the include path (using -I) for this module and any module that links
 	// against this module.  Directories listed in export_include_dirs do not need to be
 	// listed in local_include_dirs.
-	Export_include_dirs []string `android:"arch_variant"`
+	Export_include_dirs []string `android:"arch_variant,variant_prepend"`
 
 	// list of directories that will be added to the system include path
 	// using -isystem for this module and any module that links against this module.
-	Export_system_include_dirs []string `android:"arch_variant"`
+	Export_system_include_dirs []string `android:"arch_variant,variant_prepend"`
 
 	Target struct {
 		Vendor, Product struct {
diff --git a/cc/ndkstubgen/test_ndkstubgen.py b/cc/ndkstubgen/test_ndkstubgen.py
index 09551ea..c8cd056 100755
--- a/cc/ndkstubgen/test_ndkstubgen.py
+++ b/cc/ndkstubgen/test_ndkstubgen.py
@@ -413,6 +413,40 @@
         """)
         self.assertEqual(expected_version, version_file.getvalue())
 
+    def test_empty_stub(self) -> None:
+        """Tests that empty stubs can be generated.
+
+        This is not a common case, but libraries whose only behavior is to
+        interpose symbols to alter existing behavior do not need to expose
+        their interposing symbols as API, so it's possible for the stub to be
+        empty while still needing a stub to link against. libsigchain is an
+        example of this.
+        """
+        input_file = io.StringIO(textwrap.dedent("""\
+            VERSION_1 {
+                local:
+                    *;
+            };
+        """))
+        parser = symbolfile.SymbolFileParser(input_file, {}, Arch('arm'),
+                                             9, llndk=False, apex=True)
+        versions = parser.parse()
+
+        src_file = io.StringIO()
+        version_file = io.StringIO()
+        symbol_list_file = io.StringIO()
+        generator = ndkstubgen.Generator(src_file,
+                                         version_file,
+                                         symbol_list_file,
+                                         Arch('arm'),
+                                         9,
+                                         llndk=False,
+                                         apex=True)
+        generator.write(versions)
+
+        self.assertEqual('', src_file.getvalue())
+        self.assertEqual('', version_file.getvalue())
+
 
 def main() -> None:
     suite = unittest.TestLoader().loadTestsFromName(__name__)
diff --git a/scripts/Android.bp b/scripts/Android.bp
index 1c02bd0..635be10 100644
--- a/scripts/Android.bp
+++ b/scripts/Android.bp
@@ -265,3 +265,19 @@
         "linker_config_proto",
     ],
 }
+
+python_binary_host {
+    name: "get_clang_version",
+    main: "get_clang_version.py",
+    srcs: [
+        "get_clang_version.py",
+    ],
+    version: {
+        py2: {
+            enabled: false,
+        },
+        py3: {
+            enabled: true,
+        },
+    },
+}
diff --git a/scripts/get_clang_version.py b/scripts/get_clang_version.py
new file mode 100755
index 0000000..622fca1
--- /dev/null
+++ b/scripts/get_clang_version.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2021 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""A tool to report the current clang version used during build"""
+
+import os
+import re
+import sys
+
+
+ANDROID_BUILD_TOP = os.environ.get("ANDROID_BUILD_TOP", ".")
+
+def get_clang_prebuilts_version(global_go):
+  # TODO(b/187231324): Get clang version from the json file once it is no longer
+  # hard-coded in global.go
+  if global_go is None:
+      global_go = ANDROID_BUILD_TOP + '/build/soong/cc/config/global.go'
+  with open(global_go) as infile:
+    contents = infile.read()
+
+  regex_rev = r'\tClangDefaultVersion\s+= "clang-(?P<rev>r\d+[a-z]?\d?)"'
+  match_rev = re.search(regex_rev, contents)
+  if match_rev is None:
+    raise RuntimeError('Parsing clang info failed')
+  return match_rev.group('rev')
+
+
+def main():
+  global_go = sys.argv[1] if len(sys.argv) > 1 else None
+  print(get_clang_prebuilts_version(global_go));
+
+
+if __name__ == '__main__':
+  main()
diff --git a/scripts/get_clang_version_test.py b/scripts/get_clang_version_test.py
new file mode 100644
index 0000000..e57df6c
--- /dev/null
+++ b/scripts/get_clang_version_test.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2021 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+"""Unit tests for get_clang_version.py."""
+
+import unittest
+
+import get_clang_version
+
+class GetClangVersionTest(unittest.TestCase):
+  """Unit tests for get_clang_version."""
+
+  def test_get_clang_version(self):
+    """Test parsing of clang prebuilts version."""
+    self.assertIsNotNone(get_clang_version.get_clang_prebuilts_version())
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/ui/build/build.go b/ui/build/build.go
index 1187aa2..1ed9014 100644
--- a/ui/build/build.go
+++ b/ui/build/build.go
@@ -28,16 +28,20 @@
 func SetupOutDir(ctx Context, config Config) {
 	ensureEmptyFileExists(ctx, filepath.Join(config.OutDir(), "Android.mk"))
 	ensureEmptyFileExists(ctx, filepath.Join(config.OutDir(), "CleanSpec.mk"))
-	if !config.SkipKati() {
-		// Run soong_build with Kati for a hybrid build, e.g. running the
-		// AndroidMk singleton and postinstall commands. Communicate this to
-		// soong_build by writing an empty .soong.kati_enabled marker file in the
-		// soong_build output directory for the soong_build primary builder to
-		// know if the user wants to run Kati after.
-		//
-		// This does not preclude running Kati for *product configuration purposes*.
-		ensureEmptyFileExists(ctx, filepath.Join(config.SoongOutDir(), ".soong.kati_enabled"))
+
+	// Potentially write a marker file for whether kati is enabled. This is used by soong_build to
+	// potentially run the AndroidMk singleton and postinstall commands.
+	// Note that the absence of the  file does not not preclude running Kati for product
+	// configuration purposes.
+	katiEnabledMarker := filepath.Join(config.SoongOutDir(), ".soong.kati_enabled")
+	if config.SkipKatiNinja() {
+		os.Remove(katiEnabledMarker)
+		// Note that we can not remove the file for SkipKati builds yet -- some continuous builds
+		// --skip-make builds rely on kati targets being defined.
+	} else if !config.SkipKati() {
+		ensureEmptyFileExists(ctx, katiEnabledMarker)
 	}
+
 	// The ninja_build file is used by our buildbots to understand that the output
 	// can be parsed as ninja output.
 	ensureEmptyFileExists(ctx, filepath.Join(config.OutDir(), "ninja_build"))