Update linker.config.pb based on package dependency

Current linker.config.pb from the package is generated with
auto-detected provide libs, but this misses require libs which can be
detected from module dependency. This change adds extra require libs to
linker.config.pb generated from system image so it can link with modules
outside of system image.

Bug: 324995772
Test: Link succeeded from Cuttlefish with soong defined system image
Change-Id: I8563ec9ddce2a1648cc9ee55704c9483e137b710

filesystem/system_image.go

@@ -56,19 +56,40 @@ func (s *systemImage) buildLinkerConfigFile(ctx android.ModuleContext, root andr
 	output := root.Join(ctx, "system", "etc", "linker.config.pb")
 
 	// we need "Module"s for packaging items
-	var otherModules []android.Module
+	modulesInPackageByModule := make(map[android.Module]bool)
+	modulesInPackageByName := make(map[string]bool)
+
 	deps := s.gatherFilteredPackagingSpecs(ctx)
 	ctx.WalkDeps(func(child, parent android.Module) bool {
 		for _, ps := range child.PackagingSpecs() {
 			if _, ok := deps[ps.RelPathInPackage()]; ok {
-				otherModules = append(otherModules, child)
+				modulesInPackageByModule[child] = true
+				modulesInPackageByName[child.Name()] = true
+				return true
 			}
 		}
 		return true
 	})
 
+	provideModules := make([]android.Module, 0, len(modulesInPackageByModule))
+	for mod := range modulesInPackageByModule {
+		provideModules = append(provideModules, mod)
+	}
+
+	var requireModules []android.Module
+	ctx.WalkDeps(func(child, parent android.Module) bool {
+		_, parentInPackage := modulesInPackageByModule[parent]
+		_, childInPackageName := modulesInPackageByName[child.Name()]
+
+		// When parent is in the package, and child (or its variant) is not, this can be from an interface.
+		if parentInPackage && !childInPackageName {
+			requireModules = append(requireModules, child)
+		}
+		return true
+	})
+
 	builder := android.NewRuleBuilder(pctx, ctx)
-	linkerconfig.BuildLinkerConfig(ctx, builder, input, otherModules, output)
+	linkerconfig.BuildLinkerConfig(ctx, builder, input, provideModules, requireModules, output)
 	builder.Build("conv_linker_config", "Generate linker config protobuf "+output.String())
 	return output
 }

linkerconfig/linkerconfig.go

@@ -89,7 +89,7 @@ func (l *linkerConfig) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	output := android.PathForModuleOut(ctx, "linker.config.pb").OutputPath
 
 	builder := android.NewRuleBuilder(pctx, ctx)
-	BuildLinkerConfig(ctx, builder, input, nil, output)
+	BuildLinkerConfig(ctx, builder, input, nil, nil, output)
 	builder.Build("conv_linker_config", "Generate linker config protobuf "+output.String())
 
 	l.outputFilePath = output
@@ -101,7 +101,7 @@ func (l *linkerConfig) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 }
 
 func BuildLinkerConfig(ctx android.ModuleContext, builder *android.RuleBuilder,
-	input android.Path, otherModules []android.Module, output android.OutputPath) {
+	input android.Path, provideModules []android.Module, requireModules []android.Module, output android.OutputPath) {
 
 	// First, convert the input json to protobuf format
 	interimOutput := android.PathForModuleOut(ctx, "temp.pb")
@@ -111,9 +111,9 @@ func BuildLinkerConfig(ctx android.ModuleContext, builder *android.RuleBuilder,
 		FlagWithInput("-s ", input).
 		FlagWithOutput("-o ", interimOutput)
 
-	// Secondly, if there's provideLibs gathered from otherModules, append them
+	// Secondly, if there's provideLibs gathered from provideModules, append them
 	var provideLibs []string
-	for _, m := range otherModules {
+	for _, m := range provideModules {
 		if c, ok := m.(*cc.Module); ok && cc.IsStubTarget(c) {
 			for _, ps := range c.PackagingSpecs() {
 				provideLibs = append(provideLibs, ps.FileName())
@@ -122,18 +122,45 @@ func BuildLinkerConfig(ctx android.ModuleContext, builder *android.RuleBuilder,
 	}
 	provideLibs = android.FirstUniqueStrings(provideLibs)
 	sort.Strings(provideLibs)
+
+	var requireLibs []string
+	for _, m := range requireModules {
+		if c, ok := m.(*cc.Module); ok && c.HasStubsVariants() && !c.Host() {
+			requireLibs = append(requireLibs, c.ImplementationModuleName(ctx)+".so")
+		}
+	}
+
+	requireLibs = android.FirstUniqueStrings(requireLibs)
+	sort.Strings(requireLibs)
+
 	if len(provideLibs) > 0 {
+		prevOutput := interimOutput
+		interimOutput = android.PathForModuleOut(ctx, "temp_provideLibs.pb")
 		builder.Command().
 			BuiltTool("conv_linker_config").
 			Flag("append").
-			FlagWithInput("-s ", interimOutput).
+			FlagWithInput("-s ", prevOutput).
-			FlagWithOutput("-o ", output).
+			FlagWithOutput("-o ", interimOutput).
 			FlagWithArg("--key ", "provideLibs").
 			FlagWithArg("--value ", proptools.ShellEscapeIncludingSpaces(strings.Join(provideLibs, " ")))
-	} else {
+		builder.Temporary(prevOutput)
-		// If nothing to add, just cp to the final output
-		builder.Command().Text("cp").Input(interimOutput).Output(output)
 	}
+	if len(requireLibs) > 0 {
+		prevOutput := interimOutput
+		interimOutput = android.PathForModuleOut(ctx, "temp_requireLibs.pb")
+		builder.Command().
+			BuiltTool("conv_linker_config").
+			Flag("append").
+			FlagWithInput("-s ", prevOutput).
+			FlagWithOutput("-o ", interimOutput).
+			FlagWithArg("--key ", "requireLibs").
+			FlagWithArg("--value ", proptools.ShellEscapeIncludingSpaces(strings.Join(requireLibs, " ")))
+		builder.Temporary(prevOutput)
+	}
+
+	// cp to the final output
+	builder.Command().Text("cp").Input(interimOutput).Output(output)
+
 	builder.Temporary(interimOutput)
 	builder.DeleteTemporaryFiles()
 }