Merge "[rust] Add android_dylib cfg flag"

rust/library.go

@@ -431,6 +431,12 @@ func (library *libraryDecorator) sharedLibFilename(ctx ModuleContext) string {
 
 func (library *libraryDecorator) compilerFlags(ctx ModuleContext, flags Flags) Flags {
 	flags.RustFlags = append(flags.RustFlags, "-C metadata="+ctx.ModuleName())
+	if library.dylib() {
+		// We need to add a dependency on std in order to link crates as dylibs.
+		// The hack to add this dependency is guarded by the following cfg so
+		// that we don't force a dependency when it isn't needed.
+		library.baseCompiler.Properties.Cfgs = append(library.baseCompiler.Properties.Cfgs, "android_dylib")
+	}
 	flags = library.baseCompiler.compilerFlags(ctx, flags)
 	if library.shared() || library.static() {
 		library.includeDirs = append(library.includeDirs, android.PathsForModuleSrc(ctx, library.Properties.Include_dirs)...)

rust/library_test.go

@@ -85,6 +85,22 @@ func TestDylibPreferDynamic(t *testing.T) {
 	}
 }
 
+// Check that we are passing the android_dylib config flag
+func TestAndroidDylib(t *testing.T) {
+	ctx := testRust(t, `
+		rust_library_host_dylib {
+			name: "libfoo",
+			srcs: ["foo.rs"],
+			crate_name: "foo",
+		}`)
+
+	libfooDylib := ctx.ModuleForTests("libfoo", "linux_glibc_x86_64_dylib").Output("libfoo.dylib.so")
+
+	if !strings.Contains(libfooDylib.Args["rustcFlags"], "--cfg 'android_dylib'") {
+		t.Errorf("missing android_dylib cfg flag for libfoo dylib, rustcFlags: %#v", libfooDylib.Args["rustcFlags"])
+	}
+}
+
 func TestValidateLibraryStem(t *testing.T) {
 	testRustError(t, "crate_name must be defined.", `
 			rust_library_host {