Add linker.config.pb support to android_filesystem

As part of the mk->bp conversion, all modules and partitions will
eventually be built with Soong. vendor.img (built with kati) uses some
rules in build/make/core to install a /etc/linker.config.pb file. This
CL adds this logic to `android_filesystem`. This soong module will
eventually be used to build vendor.img

There are two main inputs to linker.config.pb generation for vendor.
1. PRODUCT_VENDOR_LINKER_CONFIG_FRAGMENTS, a list of json files
2. List of stub libraries installed in vendor

(1) will be passed to `android_filesystem` as `Linker_config_srcs`.

(2) has a subtle difference between kati and soong implementation. Kati
uses `SOONG_STUB_VENDOR_LIBRARIES` to determine the list of all vendor
stub libraries in the tree, and then uses `--system $TARGET_OUT/vendor`
to filter in the libraries which are actually installed. For the Soong
implementation, this will be replaced with ctx.VisitDirectDeps, followed
by child.HasStubVariants

Test: go test ./filesystem
Bug: 375686533

Change-Id: I6f9130d2aa866dcac9272b71939e40ed50a952ac

1 files changed, 21 insertions, 0 deletions

diff --git a/filesystem/filesystem_test.go b/filesystem/filesystem_test.go
index 730006116..cb27f6464 100644
--- a/filesystem/filesystem_test.go
+++ b/filesystem/filesystem_test.go
@@ -664,3 +664,24 @@ cc_library {
 	fileList := android.ContentFromFileRuleForTests(t, result.TestContext, partition.Output("fileList"))
 	android.AssertDeepEquals(t, "Shared library dep of overridden binary should not be installed", fileList, "bin/binfoo1\nlib64/libc++.so\nlib64/libc.so\nlib64/libdl.so\nlib64/libfoo2.so\nlib64/libm.so\n")
 }
+
+func TestInstallLinkerConfigFile(t *testing.T) {
+	result := fixture.RunTestWithBp(t, `
+android_filesystem {
+    name: "myfilesystem",
+    deps: ["libfoo_has_no_stubs", "libfoo_has_stubs"],
+    linker_config_srcs: ["linker.config.json"]
+}
+cc_library {
+    name: "libfoo_has_no_stubs",
+}
+cc_library {
+    name: "libfoo_has_stubs",
+    stubs: {symbol_file: "libfoo.map.txt"},
+}
+	`)
+
+	linkerConfigCmd := result.ModuleForTests("myfilesystem", "android_common").Rule("build_filesystem_image").RuleParams.Command
+	android.AssertStringDoesContain(t, "", linkerConfigCmd, "conv_linker_config proto --force -s linker.config.json")
+	android.AssertStringDoesContain(t, "", linkerConfigCmd, "--key provideLibs --value libfoo_has_stubs.so")
+}