Move prefer_rlib from binary to base compiler.

Moves the prefer_rlib property out from being exclusively a binary
property to one thats part of the base compiler properties. This
provides a little more control over the libstd linkage in our libraries.
Specifically, this enables a usecase where rust_ffi_shared needs to link
against libstd statically rather than dynamically.

Bug: 175121262
Test: New Soong tests pass.
Change-Id: If68014c684a75ba70e9d7dacbb01c7d360dc25a1

rust/binary.go

@@ -24,11 +24,6 @@ func init() {
 }
 
 type BinaryCompilerProperties struct {
-	// Change the rustlibs linkage to select rlib linkage by default for device targets.
-	// Also link libstd as an rlib as well on device targets.
-	// Note: This is the default behavior for host targets.
-	Prefer_rlib *bool `android:"arch_variant"`
-
 	// Builds this binary as a static binary. Implies prefer_rlib true.
 	//
 	// Static executables currently only support for bionic targets. Non-bionic targets will not produce a fully static
@@ -115,7 +110,7 @@ func (binary *binaryDecorator) nativeCoverage() bool {
 }
 
 func (binary *binaryDecorator) preferRlib() bool {
-	return Bool(binary.Properties.Prefer_rlib) || Bool(binary.Properties.Static_executable)
+	return Bool(binary.baseCompiler.Properties.Prefer_rlib) || Bool(binary.Properties.Static_executable)
 }
 
 func (binary *binaryDecorator) compile(ctx ModuleContext, flags Flags, deps PathDeps) android.Path {
@@ -156,8 +151,7 @@ func (binary *binaryDecorator) autoDep(ctx BaseModuleContext) autoDep {
 	// Binaries default to dylib dependencies for device, rlib for host.
 	if binary.preferRlib() {
 		return rlibAutoDep
-	}
-	if ctx.Device() {
+	} else if ctx.Device() {
 		return dylibAutoDep
 	} else {
 		return rlibAutoDep

rust/compiler.go

@@ -122,6 +122,17 @@ type BaseCompilerProperties struct {
 
 	// whether to suppress inclusion of standard crates - defaults to false
 	No_stdlibs *bool
+
+	// Change the rustlibs linkage to select rlib linkage by default for device targets.
+	// Also link libstd as an rlib as well on device targets.
+	// Note: This is the default behavior for host targets.
+	//
+	// This is primarily meant for rust_binary and rust_ffi modules where the default
+	// linkage of libstd might need to be overridden in some use cases. This should
+	// generally be avoided with other module types since it may cause collisions at
+	// linkage if all dependencies of the root binary module do not link against libstd\
+	// the same way.
+	Prefer_rlib *bool `android:"arch_variant"`
 }
 
 type baseCompiler struct {
@@ -154,9 +165,15 @@ func (compiler *baseCompiler) coverageOutputZipPath() android.OptionalPath {
 	panic("baseCompiler does not implement coverageOutputZipPath()")
 }
 
+func (compiler *baseCompiler) preferRlib() bool {
+	return Bool(compiler.Properties.Prefer_rlib)
+}
+
 func (compiler *baseCompiler) stdLinkage(ctx *depsContext) RustLinkage {
 	// For devices, we always link stdlibs in as dylibs by default.
-	if ctx.Device() {
+	if compiler.preferRlib() {
+		return RlibLinkage
+	} else if ctx.Device() {
 		return DylibLinkage
 	} else {
 		return RlibLinkage

rust/library.go

@@ -159,14 +159,6 @@ func (library *libraryDecorator) static() bool {
 	return library.MutatedProperties.VariantIsStatic
 }
 
-func (library *libraryDecorator) stdLinkage(ctx *depsContext) RustLinkage {
-	// libraries should only request the RlibLinkage when building a static FFI or when variant is StaticStd
-	if library.static() || library.MutatedProperties.VariantIsStaticStd {
-		return RlibLinkage
-	}
-	return DefaultLinkage
-}
-
 func (library *libraryDecorator) source() bool {
 	return library.MutatedProperties.VariantIsSource
 }
@@ -228,7 +220,9 @@ func (library *libraryDecorator) setSource() {
 }
 
 func (library *libraryDecorator) autoDep(ctx BaseModuleContext) autoDep {
-	if library.rlib() || library.static() {
+	if library.preferRlib() {
+		return rlibAutoDep
+	} else if library.rlib() || library.static() {
 		return rlibAutoDep
 	} else if library.dylib() || library.shared() {
 		return dylibAutoDep
@@ -237,6 +231,15 @@ func (library *libraryDecorator) autoDep(ctx BaseModuleContext) autoDep {
 	}
 }
 
+func (library *libraryDecorator) stdLinkage(ctx *depsContext) RustLinkage {
+	if library.static() || library.MutatedProperties.VariantIsStaticStd {
+		return RlibLinkage
+	} else if library.baseCompiler.preferRlib() {
+		return RlibLinkage
+	}
+	return DefaultLinkage
+}
+
 var _ compiler = (*libraryDecorator)(nil)
 var _ libraryInterface = (*libraryDecorator)(nil)
 var _ exportedFlagsProducer = (*libraryDecorator)(nil)

rust/library_test.go

@@ -251,6 +251,13 @@ func TestLibstdLinkage(t *testing.T) {
 			srcs: ["foo.rs"],
 			crate_name: "bar",
 			rustlibs: ["libfoo"],
+		}
+		rust_ffi {
+			name: "libbar.prefer_rlib",
+			srcs: ["foo.rs"],
+			crate_name: "bar",
+			rustlibs: ["libfoo"],
+			prefer_rlib: true,
 		}`)
 
 	libfooDylib := ctx.ModuleForTests("libfoo", "android_arm64_armv8-a_dylib").Module().(*Module)
@@ -260,6 +267,9 @@ func TestLibstdLinkage(t *testing.T) {
 	libbarShared := ctx.ModuleForTests("libbar", "android_arm64_armv8-a_shared").Module().(*Module)
 	libbarStatic := ctx.ModuleForTests("libbar", "android_arm64_armv8-a_static").Module().(*Module)
 
+	// prefer_rlib works the same for both rust_library and rust_ffi, so a single check is sufficient here.
+	libbarRlibStd := ctx.ModuleForTests("libbar.prefer_rlib", "android_arm64_armv8-a_shared").Module().(*Module)
+
 	if !android.InList("libstd", libfooRlibStatic.Properties.AndroidMkRlibs) {
 		t.Errorf("rlib-std variant for device rust_library_rlib does not link libstd as an rlib")
 	}
@@ -279,4 +289,8 @@ func TestLibstdLinkage(t *testing.T) {
 	if !android.InList("libfoo.rlib-std", libbarStatic.Properties.AndroidMkRlibs) {
 		t.Errorf("Device rust_ffi_static does not link dependent rustlib rlib-std variant")
 	}
+	if !android.InList("libstd", libbarRlibStd.Properties.AndroidMkRlibs) {
+		t.Errorf("rust_ffi with prefer_rlib does not link libstd as an rlib")
+	}
+
 }