Add aliases property for renaming Rust dependencies.

This is equivalent to specifying a dependency name different to the
package name in cargo, which some external crates do.

Bug: 308790322
Test: Built libgrpcio with aliases for protobuf
Change-Id: I2801222051fdd962460cc7f4900cec357f63b974

rust/compiler.go

@@ -75,6 +75,8 @@ type compiler interface {
 	strippedOutputFilePath() android.OptionalPath
 
 	checkedCrateRootPath() (android.Path, error)
+
+	Aliases() map[string]string
 }
 
 func (compiler *baseCompiler) edition() string {
@@ -140,6 +142,12 @@ type BaseCompilerProperties struct {
 	// flags to pass to the linker
 	Ld_flags []string `android:"arch_variant"`
 
+	// Rust crate dependencies to rename. Each entry should be a string of the form "dependencyname:alias".
+	//
+	// "dependencyname" here should be the name of the crate, not the Android module. This is
+	// equivalent to writing `alias = { package = "dependencyname" }` in a `Cargo.toml`.
+	Aliases []string
+
 	// list of rust rlib crate dependencies
 	Rlibs []string `android:"arch_variant"`
 
@@ -281,6 +289,18 @@ func (compiler *baseCompiler) preferRlib() bool {
 	return Bool(compiler.Properties.Prefer_rlib)
 }
 
+func (compiler *baseCompiler) Aliases() map[string]string {
+	aliases := map[string]string{}
+	for _, entry := range compiler.Properties.Aliases {
+		dep, alias, found := strings.Cut(entry, ":")
+		if !found {
+			panic(fmt.Errorf("invalid aliases entry %q missing ':'", entry))
+		}
+		aliases[dep] = alias
+	}
+	return aliases
+}
+
 func (compiler *baseCompiler) stdLinkage(ctx *depsContext) RustLinkage {
 	// For devices, we always link stdlibs in as dylibs by default.
 	if compiler.preferRlib() {

rust/rust.go

@@ -1142,6 +1142,7 @@ func collectIncludedProtos(mod *Module, dep *Module) {
 		}
 	}
 }
+
 func (mod *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 	var depPaths PathDeps
 
@@ -1433,16 +1434,29 @@ func (mod *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 	mod.transitiveAndroidMkSharedLibs = android.NewDepSet[string](android.PREORDER, directAndroidMkSharedLibs, transitiveAndroidMkSharedLibs)
 
 	var rlibDepFiles RustLibraries
+	aliases := mod.compiler.Aliases()
 	for _, dep := range directRlibDeps {
-		rlibDepFiles = append(rlibDepFiles, RustLibrary{Path: dep.UnstrippedOutputFile(), CrateName: dep.CrateName()})
+		crateName := dep.CrateName()
+		if alias, aliased := aliases[crateName]; aliased {
+			crateName = alias
+		}
+		rlibDepFiles = append(rlibDepFiles, RustLibrary{Path: dep.UnstrippedOutputFile(), CrateName: crateName})
 	}
 	var dylibDepFiles RustLibraries
 	for _, dep := range directDylibDeps {
-		dylibDepFiles = append(dylibDepFiles, RustLibrary{Path: dep.UnstrippedOutputFile(), CrateName: dep.CrateName()})
+		crateName := dep.CrateName()
+		if alias, aliased := aliases[crateName]; aliased {
+			crateName = alias
+		}
+		dylibDepFiles = append(dylibDepFiles, RustLibrary{Path: dep.UnstrippedOutputFile(), CrateName: crateName})
 	}
 	var procMacroDepFiles RustLibraries
 	for _, dep := range directProcMacroDeps {
-		procMacroDepFiles = append(procMacroDepFiles, RustLibrary{Path: dep.UnstrippedOutputFile(), CrateName: dep.CrateName()})
+		crateName := dep.CrateName()
+		if alias, aliased := aliases[crateName]; aliased {
+			crateName = alias
+		}
+		procMacroDepFiles = append(procMacroDepFiles, RustLibrary{Path: dep.UnstrippedOutputFile(), CrateName: crateName})
 	}
 
 	var staticLibDepFiles android.Paths

rust/rust_test.go

@@ -470,6 +470,35 @@ func TestLibrarySizes(t *testing.T) {
 	m.Output("libwaldo.dylib.so.bloaty.csv")
 }
 
+// Test that aliases are respected.
+func TestRustAliases(t *testing.T) {
+	ctx := testRust(t, `
+		rust_library {
+			name: "libbar",
+			crate_name: "bar",
+			srcs: ["src/lib.rs"],
+		}
+		rust_library {
+			name: "libbaz",
+			crate_name: "baz",
+			srcs: ["src/lib.rs"],
+		}
+		rust_binary {
+			name: "foo",
+			srcs: ["src/main.rs"],
+			rustlibs: ["libbar", "libbaz"],
+			aliases: ["bar:bar_renamed"],
+		}`)
+
+	fooRustc := ctx.ModuleForTests("foo", "android_arm64_armv8-a").Rule("rustc")
+	if !strings.Contains(fooRustc.Args["libFlags"], "--extern bar_renamed=out/soong/.intermediates/libbar/android_arm64_armv8-a_dylib/unstripped/libbar.dylib.so") {
+		t.Errorf("--extern bar_renamed=out/soong/.intermediates/libbar/android_arm64_armv8-a_dylib/unstripped/libbar.dylib.so flag not being passed to rustc for rust_binary with aliases. libFlags: %#v", fooRustc.Args["libFlags"])
+	}
+	if !strings.Contains(fooRustc.Args["libFlags"], "--extern baz=out/soong/.intermediates/libbaz/android_arm64_armv8-a_dylib/unstripped/libbaz.dylib.so") {
+		t.Errorf("--extern baz=out/soong/.intermediates/libbaz/android_arm64_armv8-a_dylib/unstripped/libbaz.dylib.so flag not being passed to rustc for rust_binary with aliases. libFlags: %#v", fooRustc.Args["libFlags"])
+	}
+}
+
 func assertString(t *testing.T, got, expected string) {
 	t.Helper()
 	if got != expected {