Allow platform modules to link to vendor public libraries

Normally, when building with VNDK, platform modules are not allowed to
link against vendor libraries, because the ABI of the vendor libraries
are not guaranteed to be stable and may differ across multiple vendor
images.

However, the vendor public libraries are the exceptions. Vendor public
libraries are vendor libraries that are exposed to 3rd party apps and
listed in /vendor/etc/public.libraries.txt. Since they are intended to
be exposed to public, their ABI stability is guaranteed (by definition,
though it is up to the vendor to actually guarantee it).

This change provides a way to make a vendor lib as public by defining a
module of type 'vendor_public_library' with a map file that enumerates
public symbols that are publicized:

cc_library {
   name: "libvendor",
   proprietary: true,
   ...
}

vendor_public_library {
   name: "libvendor",
   symbol_file: "libvendor.map.txt",
}

This defines a stub library module named libvendor.vendorpublic from the
map file. `shared_libs: ["libvendor"]` is redirected to the stub library
when it is from the outside of the vendor partition.

Bug: 74275385
Test: m -j
Test: cc_test.go passes
Change-Id: I5bed94d7c4282b777632ab2f0fb63c203ee313ba

Android.bp

@@ -163,6 +163,8 @@ bootstrap_go_package {
         "cc/kernel_headers.go",
 
         "cc/genrule.go",
+
+        "cc/vendor_public_library.go",
     ],
     testSrcs: [
         "cc/cc_test.go",

android/makevars.go

@@ -36,6 +36,7 @@ func androidMakeVarsProvider(ctx MakeVarsContext) {
 // Interface for other packages to use to declare make variables
 type MakeVarsContext interface {
 	Config() Config
+	SingletonContext() SingletonContext
 
 	// Verify the make variable matches the Soong version, fail the build
 	// if it does not. If the make variable is empty, just set it.
@@ -230,6 +231,10 @@ func (c *makeVarsContext) Config() Config {
 	return c.config
 }
 
+func (c *makeVarsContext) SingletonContext() SingletonContext {
+	return c.ctx
+}
+
 func (c *makeVarsContext) Eval(ninjaStr string) (string, error) {
 	return c.ctx.Eval(c.pctx, ninjaStr)
 }

android/module.go

@@ -177,6 +177,7 @@ type Module interface {
 	InstallInData() bool
 	InstallInSanitizerDir() bool
 	SkipInstall()
+	ExportedToMake() bool
 
 	AddProperties(props ...interface{})
 	GetProperties() []interface{}
@@ -507,6 +508,10 @@ func (a *ModuleBase) SkipInstall() {
 	a.commonProperties.SkipInstall = true
 }
 
+func (a *ModuleBase) ExportedToMake() bool {
+	return a.commonProperties.NamespaceExportedToMake
+}
+
 func (a *ModuleBase) computeInstallDeps(
 	ctx blueprint.ModuleContext) Paths {
 

cc/androidmk.go

@@ -383,3 +383,18 @@ func (c *ndkPrebuiltStlLinker) AndroidMk(ctx AndroidMkContext, ret *android.Andr
 		fmt.Fprintln(w, "LOCAL_COPY_TO_INTERMEDIATE_LIBRARIES := false")
 	})
 }
+
+func (c *vendorPublicLibraryStubDecorator) AndroidMk(ctx AndroidMkContext, ret *android.AndroidMkData) {
+	ret.Class = "SHARED_LIBRARIES"
+	ret.SubName = vendorPublicLibrarySuffix
+
+	ret.Extra = append(ret.Extra, func(w io.Writer, outputFile android.Path) {
+		c.libraryDecorator.androidMkWriteExportedFlags(w)
+
+		fmt.Fprintln(w, "LOCAL_BUILT_MODULE_STEM := $(LOCAL_MODULE)"+outputFile.Ext())
+		fmt.Fprintln(w, "LOCAL_STRIP_MODULE := false")
+		fmt.Fprintln(w, "LOCAL_SYSTEM_SHARED_LIBRARIES :=")
+		fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE := true")
+		fmt.Fprintln(w, "LOCAL_NO_NOTICE_FILE := true")
+	})
+}

cc/cc.go

@@ -922,6 +922,16 @@ func (c *Module) DepsMutator(actx android.BottomUpMutatorContext) {
 					}
 				} else if ctx.useVndk() && inList(entry, llndkLibraries) {
 					nonvariantLibs = append(nonvariantLibs, entry+llndkLibrarySuffix)
+				} else if (ctx.Platform() || ctx.ProductSpecific()) && inList(entry, vendorPublicLibraries) {
+					vendorPublicLib := entry + vendorPublicLibrarySuffix
+					if actx.OtherModuleExists(vendorPublicLib) {
+						nonvariantLibs = append(nonvariantLibs, vendorPublicLib)
+					} else {
+						// This can happen if vendor_public_library module is defined in a
+						// namespace that isn't visible to the current module. In that case,
+						// link to the original library.
+						nonvariantLibs = append(nonvariantLibs, entry)
+					}
 				} else {
 					nonvariantLibs = append(nonvariantLibs, entry)
 				}
@@ -1306,14 +1316,18 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 		switch depTag {
 		case sharedDepTag, sharedExportDepTag, lateSharedDepTag:
 			libName := strings.TrimSuffix(depName, llndkLibrarySuffix)
+			libName = strings.TrimSuffix(libName, vendorPublicLibrarySuffix)
 			libName = strings.TrimPrefix(libName, "prebuilt_")
 			isLLndk := inList(libName, llndkLibraries)
+			isVendorPublicLib := inList(libName, vendorPublicLibraries)
 			var makeLibName string
 			bothVendorAndCoreVariantsExist := ccDep.hasVendorVariant() || isLLndk
 			if c.useVndk() && bothVendorAndCoreVariantsExist {
 				// The vendor module in Make will have been renamed to not conflict with the core
 				// module, so update the dependency name here accordingly.
 				makeLibName = libName + vendorSuffix
+			} else if (ctx.Platform() || ctx.ProductSpecific()) && isVendorPublicLib {
+				makeLibName = libName + vendorPublicLibrarySuffix
 			} else {
 				makeLibName = libName
 			}

cc/cc_test.go

@@ -56,15 +56,18 @@ func createTestContext(t *testing.T, config android.Config, bp string) *android.
 	ctx := android.NewTestArchContext()
 	ctx.RegisterModuleType("cc_library", android.ModuleFactoryAdaptor(LibraryFactory))
 	ctx.RegisterModuleType("cc_library_shared", android.ModuleFactoryAdaptor(LibrarySharedFactory))
+	ctx.RegisterModuleType("cc_library_headers", android.ModuleFactoryAdaptor(LibraryHeaderFactory))
 	ctx.RegisterModuleType("toolchain_library", android.ModuleFactoryAdaptor(toolchainLibraryFactory))
 	ctx.RegisterModuleType("llndk_library", android.ModuleFactoryAdaptor(llndkLibraryFactory))
 	ctx.RegisterModuleType("llndk_headers", android.ModuleFactoryAdaptor(llndkHeadersFactory))
+	ctx.RegisterModuleType("vendor_public_library", android.ModuleFactoryAdaptor(vendorPublicLibraryFactory))
 	ctx.RegisterModuleType("cc_object", android.ModuleFactoryAdaptor(objectFactory))
 	ctx.RegisterModuleType("filegroup", android.ModuleFactoryAdaptor(genrule.FileGroupFactory))
 	ctx.PreDepsMutators(func(ctx android.RegisterMutatorsContext) {
 		ctx.BottomUp("image", vendorMutator).Parallel()
 		ctx.BottomUp("link", linkageMutator).Parallel()
 		ctx.BottomUp("vndk", vndkMutator).Parallel()
+		ctx.BottomUp("begin", beginMutator).Parallel()
 	})
 	ctx.Register()
 
@@ -115,6 +118,34 @@ func createTestContext(t *testing.T, config android.Config, bp string) *android.
 			name: "libdl",
 			symbol_file: "",
 		}
+		cc_library {
+			name: "libc++_static",
+			no_libgcc: true,
+			nocrt: true,
+			system_shared_libs: [],
+			stl: "none",
+			vendor_available: true,
+		}
+		cc_library {
+			name: "libc++",
+			no_libgcc: true,
+			nocrt: true,
+			system_shared_libs: [],
+			stl: "none",
+			vendor_available: true,
+			vndk: {
+				enabled: true,
+				support_system_process: true,
+			},
+		}
+		cc_library {
+			name: "libunwind_llvm",
+			no_libgcc: true,
+			nocrt: true,
+			system_shared_libs: [],
+			stl: "none",
+			vendor_available: true,
+		}
 
 		cc_object {
 			name: "crtbegin_so",
@@ -1077,16 +1108,20 @@ func TestStaticLibDepReordering(t *testing.T) {
 	cc_library {
 		name: "a",
 		static_libs: ["b", "c", "d"],
+		stl: "none",
 	}
 	cc_library {
 		name: "b",
+		stl: "none",
 	}
 	cc_library {
 		name: "c",
 		static_libs: ["b"],
+		stl: "none",
 	}
 	cc_library {
 		name: "d",
+		stl: "none",
 	}
 
 	`)
@@ -1111,13 +1146,16 @@ func TestStaticLibDepReorderingWithShared(t *testing.T) {
 	cc_library {
 		name: "a",
 		static_libs: ["b", "c"],
+		stl: "none",
 	}
 	cc_library {
 		name: "b",
+		stl: "none",
 	}
 	cc_library {
 		name: "c",
 		shared_libs: ["b"],
+		stl: "none",
 	}
 
 	`)
@@ -1249,3 +1287,68 @@ func TestCompilerFlags(t *testing.T) {
 		}
 	}
 }
+
+func TestVendorPublicLibraries(t *testing.T) {
+	ctx := testCc(t, `
+	cc_library_headers {
+		name: "libvendorpublic_headers",
+		export_include_dirs: ["my_include"],
+	}
+	vendor_public_library {
+		name: "libvendorpublic",
+		symbol_file: "",
+		export_public_headers: ["libvendorpublic_headers"],
+	}
+	cc_library {
+		name: "libvendorpublic",
+		srcs: ["foo.c"],
+		vendor: true,
+		no_libgcc: true,
+		nocrt: true,
+	}
+
+	cc_library {
+		name: "libsystem",
+		shared_libs: ["libvendorpublic"],
+		vendor: false,
+		srcs: ["foo.c"],
+		no_libgcc: true,
+		nocrt: true,
+	}
+	cc_library {
+		name: "libvendor",
+		shared_libs: ["libvendorpublic"],
+		vendor: true,
+		srcs: ["foo.c"],
+		no_libgcc: true,
+		nocrt: true,
+	}
+	`)
+
+	variant := "android_arm64_armv8-a_core_shared"
+
+	// test if header search paths are correctly added
+	// _static variant is used since _shared reuses *.o from the static variant
+	cc := ctx.ModuleForTests("libsystem", strings.Replace(variant, "_shared", "_static", 1)).Rule("cc")
+	cflags := cc.Args["cFlags"]
+	if !strings.Contains(cflags, "-Imy_include") {
+		t.Errorf("cflags for libsystem must contain -Imy_include, but was %#v.", cflags)
+	}
+
+	// test if libsystem is linked to the stub
+	ld := ctx.ModuleForTests("libsystem", variant).Rule("ld")
+	libflags := ld.Args["libFlags"]
+	stubPaths := getOutputPaths(ctx, variant, []string{"libvendorpublic" + vendorPublicLibrarySuffix})
+	if !strings.Contains(libflags, stubPaths[0].String()) {
+		t.Errorf("libflags for libsystem must contain %#v, but was %#v", stubPaths[0], libflags)
+	}
+
+	// test if libvendor is linked to the real shared lib
+	ld = ctx.ModuleForTests("libvendor", strings.Replace(variant, "_core", "_vendor", 1)).Rule("ld")
+	libflags = ld.Args["libFlags"]
+	stubPaths = getOutputPaths(ctx, strings.Replace(variant, "_core", "_vendor", 1), []string{"libvendorpublic"})
+	if !strings.Contains(libflags, stubPaths[0].String()) {
+		t.Errorf("libflags for libvendor must contain %#v, but was %#v", stubPaths[0], libflags)
+	}
+
+}

cc/makevars.go

@@ -100,6 +100,21 @@ func makeVarsProvider(ctx android.MakeVarsContext) {
 	ctx.Strict("LLNDK_LIBRARIES", strings.Join(llndkLibraries, " "))
 	ctx.Strict("VNDK_PRIVATE_LIBRARIES", strings.Join(vndkPrivateLibraries, " "))
 
+	// Filter vendor_public_library that are exported to make
+	exportedVendorPublicLibraries := []string{}
+	ctx.SingletonContext().VisitAllModules(func(module android.Module) {
+		if ccModule, ok := module.(*Module); ok {
+			baseName := ccModule.BaseModuleName()
+			if inList(baseName, vendorPublicLibraries) && module.ExportedToMake() {
+				if !inList(baseName, exportedVendorPublicLibraries) {
+					exportedVendorPublicLibraries = append(exportedVendorPublicLibraries, baseName)
+				}
+			}
+		}
+	})
+	sort.Strings(exportedVendorPublicLibraries)
+	ctx.Strict("VENDOR_PUBLIC_LIBRARIES", strings.Join(exportedVendorPublicLibraries, " "))
+
 	sort.Strings(lsdumpPaths)
 	ctx.Strict("LSDUMP_PATHS", strings.Join(lsdumpPaths, " "))
 

cc/vendor_public_library.go

@@ -0,0 +1,150 @@
+// Copyright 2018 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cc
+
+import (
+	"strings"
+	"sync"
+
+	"android/soong/android"
+)
+
+var (
+	vendorPublicLibrarySuffix = ".vendorpublic"
+
+	vendorPublicLibraries     = []string{}
+	vendorPublicLibrariesLock sync.Mutex
+)
+
+// Creates a stub shared library for a vendor public library. Vendor public libraries
+// are vendor libraries (owned by them and installed to /vendor partition) that are
+// exposed to Android apps via JNI. The libraries are made public by being listed in
+// /vendor/etc/public.libraries.txt.
+//
+// This stub library is a build-time only artifact that provides symbols that are
+// exposed from a vendor public library.
+//
+// Example:
+//
+// vendor_public_library {
+//     name: "libfoo",
+//     symbol_file: "libfoo.map.txt",
+//     export_public_headers: ["libfoo_headers"],
+// }
+//
+// cc_headers {
+//     name: "libfoo_headers",
+//     export_include_dirs: ["include"],
+// }
+//
+type vendorPublicLibraryProperties struct {
+	// Relative path to the symbol map.
+	Symbol_file *string
+
+	// Whether the system library uses symbol versions.
+	Unversioned *bool
+
+	// list of header libs to re-export include directories from.
+	Export_public_headers []string `android:"arch_variant"`
+}
+
+type vendorPublicLibraryStubDecorator struct {
+	*libraryDecorator
+
+	Properties vendorPublicLibraryProperties
+
+	versionScriptPath android.ModuleGenPath
+}
+
+func (stub *vendorPublicLibraryStubDecorator) Name(name string) string {
+	return name + vendorPublicLibrarySuffix
+}
+
+func (stub *vendorPublicLibraryStubDecorator) compilerInit(ctx BaseModuleContext) {
+	stub.baseCompiler.compilerInit(ctx)
+
+	name := ctx.baseModuleName()
+	if strings.HasSuffix(name, vendorPublicLibrarySuffix) {
+		ctx.PropertyErrorf("name", "Do not append %q manually, just use the base name", vendorPublicLibrarySuffix)
+	}
+
+	vendorPublicLibrariesLock.Lock()
+	defer vendorPublicLibrariesLock.Unlock()
+	for _, lib := range vendorPublicLibraries {
+		if lib == name {
+			return
+		}
+	}
+	vendorPublicLibraries = append(vendorPublicLibraries, name)
+}
+
+func (stub *vendorPublicLibraryStubDecorator) compilerFlags(ctx ModuleContext, flags Flags, deps PathDeps) Flags {
+	flags = stub.baseCompiler.compilerFlags(ctx, flags, deps)
+	return addStubLibraryCompilerFlags(flags)
+}
+
+func (stub *vendorPublicLibraryStubDecorator) compile(ctx ModuleContext, flags Flags, deps PathDeps) Objects {
+	objs, versionScript := compileStubLibrary(ctx, flags, String(stub.Properties.Symbol_file), "current", "")
+	stub.versionScriptPath = versionScript
+	return objs
+}
+
+func (stub *vendorPublicLibraryStubDecorator) linkerDeps(ctx DepsContext, deps Deps) Deps {
+	headers := stub.Properties.Export_public_headers
+	deps.HeaderLibs = append(deps.HeaderLibs, headers...)
+	deps.ReexportHeaderLibHeaders = append(deps.ReexportHeaderLibHeaders, headers...)
+	return deps
+}
+
+func (stub *vendorPublicLibraryStubDecorator) linkerFlags(ctx ModuleContext, flags Flags) Flags {
+	stub.libraryDecorator.libName = strings.TrimSuffix(ctx.ModuleName(), vendorPublicLibrarySuffix)
+	return stub.libraryDecorator.linkerFlags(ctx, flags)
+}
+
+func (stub *vendorPublicLibraryStubDecorator) link(ctx ModuleContext, flags Flags, deps PathDeps,
+	objs Objects) android.Path {
+	if !Bool(stub.Properties.Unversioned) {
+		linkerScriptFlag := "-Wl,--version-script," + stub.versionScriptPath.String()
+		flags.LdFlags = append(flags.LdFlags, linkerScriptFlag)
+	}
+	return stub.libraryDecorator.link(ctx, flags, deps, objs)
+}
+
+func vendorPublicLibraryFactory() android.Module {
+	module, library := NewLibrary(android.DeviceSupported)
+	library.BuildOnlyShared()
+	module.stl = nil
+	module.sanitize = nil
+	library.StripProperties.Strip.None = BoolPtr(true)
+
+	stub := &vendorPublicLibraryStubDecorator{
+		libraryDecorator: library,
+	}
+	module.compiler = stub
+	module.linker = stub
+	module.installer = nil
+
+	module.AddProperties(
+		&stub.Properties,
+		&library.MutatedProperties,
+		&library.flagExporter.Properties)
+
+	android.InitAndroidArchModule(module, android.DeviceSupported, android.MultilibBoth)
+	return module
+}
+
+func init() {
+	android.RegisterModuleType("vendor_public_library", vendorPublicLibraryFactory)
+}