android_system_image that generates linker.config.pb

android_system_image module type is a specialization of the
android_filesystem module type. Currently, it adds a build rule for
creating linker.config.pb from the information about all the other files
in the filesystem and includes linker.config.pb to the filesystem as
well.

To do so, the filesystem module now provides a function pointer which
subtype modules like android_system_image can implement to pass extra
files that they want to package in the filesystem.

In addition, the linkerconfig package is revised to make it possible to
build linker.config.pb file outside of the package.

Bug: 185391776
Test: m microdroid and inspect etc/linker.config.pb in it.

Change-Id: Id89c40b519213062860d7306029b8413d8d36a2d

2 files changed, 53 insertions, 13 deletions

diff --git a/linkerconfig/Android.bp b/linkerconfig/Android.bp
index 9161f0eb5..76a632517 100644
--- a/linkerconfig/Android.bp
+++ b/linkerconfig/Android.bp
@@ -9,6 +9,7 @@ bootstrap_go_package {
         "blueprint",
         "soong",
         "soong-android",
+        "soong-cc",
         "soong-etc",
     ],
     srcs: [
diff --git a/linkerconfig/linkerconfig.go b/linkerconfig/linkerconfig.go
index 241cac691..8d0ad7cf2 100644
--- a/linkerconfig/linkerconfig.go
+++ b/linkerconfig/linkerconfig.go
@@ -15,11 +15,15 @@
 package linkerconfig
 
 import (
-	"android/soong/android"
-	"android/soong/etc"
 	"fmt"
+	"sort"
+	"strings"
 
 	"github.com/google/blueprint/proptools"
+
+	"android/soong/android"
+	"android/soong/cc"
+	"android/soong/etc"
 )
 
 var (
@@ -81,24 +85,59 @@ func (l *linkerConfig) OutputFiles(tag string) (android.Paths, error) {
 }
 
 func (l *linkerConfig) GenerateAndroidBuildActions(ctx android.ModuleContext) {
-	inputFile := android.PathForModuleSrc(ctx, android.String(l.properties.Src))
-	l.outputFilePath = android.PathForModuleOut(ctx, "linker.config.pb").OutputPath
-	l.installDirPath = android.PathForModuleInstall(ctx, "etc")
-	linkerConfigRule := android.NewRuleBuilder(pctx, ctx)
-	linkerConfigRule.Command().
-		BuiltTool("conv_linker_config").
-		Flag("proto").
-		FlagWithInput("-s ", inputFile).
-		FlagWithOutput("-o ", l.outputFilePath)
-	linkerConfigRule.Build("conv_linker_config",
-		"Generate linker config protobuf "+l.outputFilePath.String())
+	input := android.PathForModuleSrc(ctx, android.String(l.properties.Src))
+	output := android.PathForModuleOut(ctx, "linker.config.pb").OutputPath
+
+	builder := android.NewRuleBuilder(pctx, ctx)
+	BuildLinkerConfig(ctx, builder, input, nil, output)
+	builder.Build("conv_linker_config", "Generate linker config protobuf "+output.String())
 
+	l.outputFilePath = output
+	l.installDirPath = android.PathForModuleInstall(ctx, "etc")
 	if !proptools.BoolDefault(l.properties.Installable, true) {
 		l.SkipInstall()
 	}
 	ctx.InstallFile(l.installDirPath, l.outputFilePath.Base(), l.outputFilePath)
 }
 
+func BuildLinkerConfig(ctx android.ModuleContext, builder *android.RuleBuilder,
+	input android.Path, otherModules []android.Module, output android.OutputPath) {
+
+	// First, convert the input json to protobuf format
+	interimOutput := android.PathForModuleOut(ctx, "temp.pb")
+	builder.Command().
+		BuiltTool("conv_linker_config").
+		Flag("proto").
+		FlagWithInput("-s ", input).
+		FlagWithOutput("-o ", interimOutput)
+
+	// Secondly, if there's provideLibs gathered from otherModules, append them
+	var provideLibs []string
+	for _, m := range otherModules {
+		if c, ok := m.(*cc.Module); ok && cc.IsStubTarget(c) {
+			for _, ps := range c.PackagingSpecs() {
+				provideLibs = append(provideLibs, ps.FileName())
+			}
+		}
+	}
+	provideLibs = android.FirstUniqueStrings(provideLibs)
+	sort.Strings(provideLibs)
+	if len(provideLibs) > 0 {
+		builder.Command().
+			BuiltTool("conv_linker_config").
+			Flag("append").
+			FlagWithInput("-s ", interimOutput).
+			FlagWithOutput("-o ", output).
+			FlagWithArg("--key ", "provideLibs").
+			FlagWithArg("--value ", proptools.ShellEscapeIncludingSpaces(strings.Join(provideLibs, " ")))
+	} else {
+		// If nothing to add, just cp to the final output
+		builder.Command().Text("cp").Input(interimOutput).Output(output)
+	}
+	builder.Temporary(interimOutput)
+	builder.DeleteTemporaryFiles()
+}
+
 // linker_config generates protobuf file from json file. This protobuf file will be used from
 // linkerconfig while generating ld.config.txt. Format of this file can be found from
 // https://android.googlesource.com/platform/system/linkerconfig/+/master/README.md