[rust] Add SourceProviders as crates support.

This allows SourceProvider modules to create rust_library variants so
that generated source can be referenced as an external crate rather than
via an include macro. This is done by including rust_bindgen modules
like any other library, as a dependency in either rlibs, dylibs, or
rustlibs.

This renames the stem and flags properties for rust_bindgen modules to
source_stem and bindgen_flags, respectively. This deconflicts with the
usage in baseCompiler.

This also removes 'subName' from the Module struct and moves it over to
SourceProvider, which was the only user. This allows us to set it in
baseSourceProvider's AndroidMk; setting it in Module's AndroidMk was
causing problems finding NOTICE files for bindgen library variants.

Bug: 159064919
Test: New Soong tests pass.
Test: Local test rust_binary can use rust_bindgen module as a crate.

Change-Id: Ieb2cb614c2dd0b5aa7120541d77f6f822a6a1806

rust/androidmk.go

@@ -55,7 +55,6 @@ func (mod *Module) AndroidMk() android.AndroidMkData {
 	ret := android.AndroidMkData{
 		OutputFile: mod.outputFile,
 		Include:    "$(BUILD_SYSTEM)/soong_rust_prebuilt.mk",
-		SubName:    mod.subName,
 		Extra: []android.AndroidMkExtraFunc{
 			func(w io.Writer, outputFile android.Path) {
 				if len(mod.Properties.AndroidMkRlibs) > 0 {
@@ -76,9 +75,11 @@ func (mod *Module) AndroidMk() android.AndroidMkData {
 			},
 		},
 	}
-	if mod.compiler != nil {
+
+	if mod.compiler != nil && !mod.compiler.Disabled() {
 		mod.subAndroidMk(&ret, mod.compiler)
 	} else if mod.sourceProvider != nil {
+		// If the compiler is disabled, this is a SourceProvider.
 		mod.subAndroidMk(&ret, mod.sourceProvider)
 	}
 	ret.SubName += mod.Properties.SubName
@@ -162,6 +163,7 @@ func (sourceProvider *baseSourceProvider) AndroidMk(ctx AndroidMkContext, ret *a
 	outFile := sourceProvider.outputFile
 	ret.Class = "ETC"
 	ret.OutputFile = android.OptionalPathForPath(outFile)
+	ret.SubName += sourceProvider.subName
 	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
 		_, file := filepath.Split(outFile.String())
 		stem, suffix, _ := android.SplitFileExt(file)

rust/bindgen.go

@@ -61,7 +61,7 @@ type BindgenProperties struct {
 	Wrapper_src *string `android:"path,arch_variant"`
 
 	// list of bindgen-specific flags and options
-	Flags []string `android:"arch_variant"`
+	Bindgen_flags []string `android:"arch_variant"`
 
 	// list of clang flags required to correctly interpret the headers.
 	Cflags []string `android:"arch_variant"`
@@ -121,7 +121,7 @@ func (b *bindgenDecorator) generateSource(ctx android.ModuleContext, deps PathDe
 	}
 
 	bindgenFlags := defaultBindgenFlags
-	bindgenFlags = append(bindgenFlags, strings.Join(b.Properties.Flags, " "))
+	bindgenFlags = append(bindgenFlags, strings.Join(b.Properties.Bindgen_flags, " "))
 
 	wrapperFile := android.OptionalPathForModuleSrc(ctx, b.Properties.Wrapper_src)
 	if !wrapperFile.Valid() {
@@ -170,7 +170,13 @@ func NewRustBindgen(hod android.HostOrDeviceSupported) (*Module, *bindgenDecorat
 		baseSourceProvider: NewSourceProvider(),
 		Properties:         BindgenProperties{},
 	}
+
+	_, library := NewRustLibrary(hod)
+	library.BuildOnlyRust()
+	library.sourceProvider = bindgen
+
 	module.sourceProvider = bindgen
+	module.compiler = library
 
 	return module, bindgen
 }

rust/bindgen_test.go

@@ -24,8 +24,10 @@ func TestRustBindgen(t *testing.T) {
 		rust_bindgen {
 			name: "libbindgen",
 			wrapper_src: "src/any.h",
-			stem: "bindings",
+			crate_name: "bindgen",
-			flags: ["--bindgen-flag"],
+			stem: "libbindgen",
+			source_stem: "bindings",
+			bindgen_flags: ["--bindgen-flag"],
 			cflags: ["--clang-flag"],
 			shared_libs: ["libfoo_shared"],
 			static_libs: ["libfoo_static"],
@@ -38,7 +40,6 @@ func TestRustBindgen(t *testing.T) {
 			name: "libfoo_static",
 			export_include_dirs: ["static_include"],
 		}
-
 	`)
 	libbindgen := ctx.ModuleForTests("libbindgen", "android_arm64_armv8-a").Output("bindings.rs")
 	if !strings.Contains(libbindgen.Args["flags"], "--bindgen-flag") {

rust/builder_test.go

@@ -28,12 +28,14 @@ func TestSourceProviderCollision(t *testing.T) {
 		}
 		rust_bindgen {
 			name: "libbindings1",
-			stem: "bindings",
+			source_stem: "bindings",
+			crate_name: "bindings1",
 			wrapper_src: "src/any.h",
 		}
 		rust_bindgen {
 			name: "libbindings2",
-			stem: "bindings",
+			source_stem: "bindings",
+			crate_name: "bindings2",
 			wrapper_src: "src/any.h",
 		}
 	`)

rust/compiler.go

@@ -81,7 +81,10 @@ type BaseCompilerProperties struct {
 	// list of C static library dependencies
 	Static_libs []string `android:"arch_variant"`
 
-	// crate name, required for libraries. This must be the expected extern crate name used in source
+	// crate name, required for modules which produce Rust libraries: rust_library, rust_ffi and SourceProvider
+	// modules which create library variants (rust_bindgen). This must be the expected extern crate name used in
+	// source, and is required to conform to an enforced format matching library output files (if the output file is
+	// lib<someName><suffix>, the crate_name property must be <someName>).
 	Crate_name string `android:"arch_variant"`
 
 	// list of features to enable for this crate
@@ -120,6 +123,14 @@ type baseCompiler struct {
 	distFile              android.OptionalPath
 }
 
+func (compiler *baseCompiler) Disabled() bool {
+	return false
+}
+
+func (compiler *baseCompiler) SetDisabled() {
+	panic("baseCompiler does not implement SetDisabled()")
+}
+
 func (compiler *baseCompiler) coverageOutputZipPath() android.OptionalPath {
 	panic("baseCompiler does not implement coverageOutputZipPath()")
 }

rust/library.go

@@ -69,6 +69,10 @@ type LibraryMutatedProperties struct {
 	VariantIsShared bool `blueprint:"mutated"`
 	// This variant is a static library
 	VariantIsStatic bool `blueprint:"mutated"`
+
+	// This variant is disabled and should not be compiled
+	// (used for SourceProvider variants that produce only source)
+	VariantIsDisabled bool `blueprint:"mutated"`
 }
 
 type libraryDecorator struct {
@@ -78,6 +82,7 @@ type libraryDecorator struct {
 	Properties        LibraryCompilerProperties
 	MutatedProperties LibraryMutatedProperties
 	includeDirs       android.Paths
+	sourceProvider    SourceProvider
 }
 
 type libraryInterface interface {
@@ -367,8 +372,13 @@ func (library *libraryDecorator) compilerFlags(ctx ModuleContext, flags Flags) F
 
 func (library *libraryDecorator) compile(ctx ModuleContext, flags Flags, deps PathDeps) android.Path {
 	var outputFile android.WritablePath
+	var srcPath android.Path
 
-	srcPath, _ := srcPathFromModuleSrcs(ctx, library.baseCompiler.Properties.Srcs)
+	if library.sourceProvider != nil {
+		srcPath = library.sourceProvider.Srcs()[0]
+	} else {
+		srcPath, _ = srcPathFromModuleSrcs(ctx, library.baseCompiler.Properties.Srcs)
+	}
 
 	flags.RustFlags = append(flags.RustFlags, deps.depFlags...)
 
@@ -430,6 +440,14 @@ func (library *libraryDecorator) getStem(ctx ModuleContext) string {
 	return stem + String(library.baseCompiler.Properties.Suffix)
 }
 
+func (library *libraryDecorator) Disabled() bool {
+	return library.MutatedProperties.VariantIsDisabled
+}
+
+func (library *libraryDecorator) SetDisabled() {
+	library.MutatedProperties.VariantIsDisabled = true
+}
+
 var validCrateName = regexp.MustCompile("[^a-zA-Z0-9_]+")
 
 func validateLibraryStem(ctx BaseModuleContext, filename string, crate_name string) {
@@ -455,12 +473,23 @@ func LibraryMutator(mctx android.BottomUpMutatorContext) {
 		switch library := m.compiler.(type) {
 		case libraryInterface:
 			if library.buildRlib() && library.buildDylib() {
-				modules := mctx.CreateLocalVariations("rlib", "dylib")
+				variants := []string{"rlib", "dylib"}
+				if m.sourceProvider != nil {
+					variants = append(variants, "")
+				}
+				modules := mctx.CreateLocalVariations(variants...)
+
 				rlib := modules[0].(*Module)
 				dylib := modules[1].(*Module)
-
 				rlib.compiler.(libraryInterface).setRlib()
 				dylib.compiler.(libraryInterface).setDylib()
+
+				if m.sourceProvider != nil {
+					// This library is SourceProvider generated, so the non-library-producing
+					// variant needs to disable it's compiler and skip installation.
+					sourceProvider := modules[2].(*Module)
+					sourceProvider.compiler.SetDisabled()
+				}
 			} else if library.buildRlib() {
 				modules := mctx.CreateLocalVariations("rlib")
 				modules[0].(*Module).compiler.(libraryInterface).setRlib()
@@ -468,6 +497,11 @@ func LibraryMutator(mctx android.BottomUpMutatorContext) {
 				modules := mctx.CreateLocalVariations("dylib")
 				modules[0].(*Module).compiler.(libraryInterface).setDylib()
 			}
+
+			if m.sourceProvider != nil {
+				// Alias the non-library variant to the empty-string variant.
+				mctx.AliasVariation("")
+			}
 		}
 	}
 }

rust/rust.go

@@ -64,6 +64,7 @@ type BaseProperties struct {
 	AndroidMkStaticLibs    []string
 
 	SubName string `blueprint:"mutated"`
+
 	PreventInstall bool
 	HideFromMake   bool
 }
@@ -83,9 +84,9 @@ type Module struct {
 	cachedToolchain  config.Toolchain
 	sourceProvider   SourceProvider
 	subAndroidMkOnce map[subAndroidMkProvider]bool
-	outputFile       android.OptionalPath
 
-	subName string
+	outputFile    android.OptionalPath
+	generatedFile android.OptionalPath
 }
 
 func (mod *Module) OutputFiles(tag string) (android.Paths, error) {
@@ -285,6 +286,9 @@ type compiler interface {
 	relativeInstallPath() string
 
 	nativeCoverage() bool
+
+	Disabled() bool
+	SetDisabled()
 }
 
 type exportedFlagsProducer interface {
@@ -667,16 +671,21 @@ func (mod *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 		flags, deps = mod.clippy.flags(ctx, flags, deps)
 	}
 
-	if mod.compiler != nil {
+	// SourceProvider needs to call generateSource() before compiler calls compile() so it can provide the source.
+	// TODO(b/162588681) This shouldn't have to run for every variant.
+	if mod.sourceProvider != nil {
+		generatedFile := mod.sourceProvider.generateSource(ctx, deps)
+		mod.generatedFile = android.OptionalPathForPath(generatedFile)
+		mod.sourceProvider.setSubName(ctx.ModuleSubDir())
+	}
+
+	if mod.compiler != nil && !mod.compiler.Disabled() {
 		outputFile := mod.compiler.compile(ctx, flags, deps)
+
 		mod.outputFile = android.OptionalPathForPath(outputFile)
-		if !mod.Properties.PreventInstall {
+		if mod.outputFile.Valid() && !mod.Properties.PreventInstall {
 			mod.compiler.install(ctx, mod.outputFile.Path())
 		}
-	} else if mod.sourceProvider != nil {
-		outputFile := mod.sourceProvider.generateSource(ctx, deps)
-		mod.outputFile = android.OptionalPathForPath(outputFile)
-		mod.subName = ctx.ModuleSubDir()
 	}
 }
 
@@ -685,7 +694,8 @@ func (mod *Module) deps(ctx DepsContext) Deps {
 
 	if mod.compiler != nil {
 		deps = mod.compiler.compilerDeps(ctx, deps)
-	} else if mod.sourceProvider != nil {
+	}
+	if mod.sourceProvider != nil {
 		deps = mod.sourceProvider.sourceProviderDeps(ctx, deps)
 	}
 
@@ -755,11 +765,6 @@ func (mod *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 		if rustDep, ok := dep.(*Module); ok && !rustDep.CcLibraryInterface() {
 			//Handle Rust Modules
 
-			linkFile := rustDep.outputFile
-			if !linkFile.Valid() {
-				ctx.ModuleErrorf("Invalid output file when adding dep %q to %q", depName, ctx.ModuleName())
-			}
-
 			switch depTag {
 			case dylibDepTag:
 				dylib, ok := rustDep.compiler.(libraryInterface)
@@ -808,6 +813,12 @@ func (mod *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 			}
 
 			if depTag == dylibDepTag || depTag == rlibDepTag || depTag == procMacroDepTag {
+				linkFile := rustDep.outputFile
+				if !linkFile.Valid() {
+					ctx.ModuleErrorf("Invalid output file when adding dep %q to %q",
+						depName, ctx.ModuleName())
+					return
+				}
 				linkDir := linkPathFromFilePath(linkFile.Path())
 				if lib, ok := mod.compiler.(exportedFlagsProducer); ok {
 					lib.exportLinkDirs(linkDir)
@@ -826,7 +837,6 @@ func (mod *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 					return
 				}
 			}
-
 			linkFile := ccDep.OutputFile()
 			linkPath := linkPathFromFilePath(linkFile.Path())
 			libName := libNameFromFilePath(linkFile.Path())

rust/rust_test.go

@@ -233,6 +233,7 @@ func TestSourceProviderDeps(t *testing.T) {
 				":my_generator",
 				":libbindings",
 			],
+			rlibs: ["libbindings"],
 		}
 		rust_proc_macro {
 			name: "libprocmacro",
@@ -241,6 +242,7 @@ func TestSourceProviderDeps(t *testing.T) {
 				":my_generator",
 				":libbindings",
 			],
+			rlibs: ["libbindings"],
 			crate_name: "procmacro",
 		}
 		rust_library {
@@ -248,7 +250,9 @@ func TestSourceProviderDeps(t *testing.T) {
 			srcs: [
 				"foo.rs",
 				":my_generator",
-				":libbindings"],
+				":libbindings",
+			],
+			rlibs: ["libbindings"],
 			crate_name: "foo",
 		}
 		genrule {
@@ -260,7 +264,8 @@ func TestSourceProviderDeps(t *testing.T) {
 		}
 		rust_bindgen {
 			name: "libbindings",
-			stem: "bindings",
+			crate_name: "bindings",
+			source_stem: "bindings",
 			host_supported: true,
 			wrapper_src: "src/any.h",
         }
@@ -289,6 +294,21 @@ func TestSourceProviderDeps(t *testing.T) {
 	if !android.SuffixInList(libprocmacro.Implicits.Strings(), "/out/any.rs") {
 		t.Errorf("genrule generated source not included as implicit input for libprocmacro; Implicits %#v", libfoo.Implicits.Strings())
 	}
+
+	// Check that our bindings are picked up as crate dependencies as well
+	libfooMod := ctx.ModuleForTests("libfoo", "android_arm64_armv8-a_dylib").Module().(*Module)
+	if !android.InList("libbindings", libfooMod.Properties.AndroidMkRlibs) {
+		t.Errorf("bindgen dependency not detected as a rlib dependency (dependency missing from AndroidMkRlibs)")
+	}
+	fizzBuzzMod := ctx.ModuleForTests("fizz-buzz-dep", "android_arm64_armv8-a").Module().(*Module)
+	if !android.InList("libbindings", fizzBuzzMod.Properties.AndroidMkRlibs) {
+		t.Errorf("bindgen dependency not detected as a rlib dependency (dependency missing from AndroidMkRlibs)")
+	}
+	libprocmacroMod := ctx.ModuleForTests("libprocmacro", "linux_glibc_x86_64").Module().(*Module)
+	if !android.InList("libbindings", libprocmacroMod.Properties.AndroidMkRlibs) {
+		t.Errorf("bindgen dependency not detected as a rlib dependency (dependency missing from AndroidMkRlibs)")
+	}
+
 }
 
 func TestSourceProviderTargetMismatch(t *testing.T) {
@@ -305,7 +325,8 @@ func TestSourceProviderTargetMismatch(t *testing.T) {
 		}
 		rust_bindgen {
 			name: "libbindings",
-			stem: "bindings",
+			crate_name: "bindings",
+			source_stem: "bindings",
 			wrapper_src: "src/any.h",
 		}
 	`)

rust/source_provider.go

@@ -19,8 +19,13 @@ import (
 )
 
 type SourceProviderProperties struct {
-	// sets name of the output
+	// name for the generated source file. Defaults to module name (e.g. moduleNameFoo.rs is produced by default).
-	Stem *string `android:"arch_variant"`
+	// Importantly, the inherited "stem" property for this module sets the output filename for the generated library
+	// variants only
+	Source_stem *string `android:"arch_variant"`
+
+	// crate name, used for the library variant of this source provider. See additional details in rust_library.
+	Crate_name string `android:"arch_variant"`
 }
 
 type baseSourceProvider struct {
@@ -28,6 +33,7 @@ type baseSourceProvider struct {
 
 	outputFile       android.Path
 	subAndroidMkOnce map[subAndroidMkProvider]bool
+	subName          string
 }
 
 var _ SourceProvider = (*baseSourceProvider)(nil)
@@ -37,6 +43,7 @@ type SourceProvider interface {
 	Srcs() android.Paths
 	sourceProviderProps() []interface{}
 	sourceProviderDeps(ctx DepsContext, deps Deps) Deps
+	setSubName(subName string)
 }
 
 func (sp *baseSourceProvider) Srcs() android.Paths {
@@ -59,8 +66,8 @@ func NewSourceProvider() *baseSourceProvider {
 
 func (sp *baseSourceProvider) getStem(ctx android.ModuleContext) string {
 	stem := ctx.ModuleName()
-	if String(sp.Properties.Stem) != "" {
+	if String(sp.Properties.Source_stem) != "" {
-		stem = String(sp.Properties.Stem)
+		stem = String(sp.Properties.Source_stem)
 	}
 	return stem
 }
@@ -68,3 +75,7 @@ func (sp *baseSourceProvider) getStem(ctx android.ModuleContext) string {
 func (sp *baseSourceProvider) sourceProviderDeps(ctx DepsContext, deps Deps) Deps {
 	return deps
 }
+
+func (sp *baseSourceProvider) setSubName(subName string) {
+	sp.subName = subName
+}