Add USE_D8_DESUGAR option in build/soong

Add an option to use D8's desugar instead of the standalone version.

USE_D8_DESUGAR=true m would trigger DCHECK in dex2oat unless
https://android-review.googlesource.com/c/platform/art/+/562595 is
patched in as well.

Bug: 69329508
Test: m && USE_D8_DESUGAR=false m

Change-Id: I864d88e257a2ba0b7f19aa5cced537301950e963

java/builder.go

@@ -161,6 +161,20 @@ var (
 		},
 		"outDir", "dxFlags")
 
+	d8 = pctx.AndroidStaticRule("d8",
+		blueprint.RuleParams{
+			Command: `rm -rf "$outDir" && mkdir -p "$outDir" && ` +
+				`${config.D8Cmd} --output $outDir $dxFlags $in && ` +
+				`${config.SoongZipCmd} -o $outDir/classes.dex.jar -C $outDir -D $outDir && ` +
+				`${config.MergeZipsCmd} -D -stripFile "*.class" $out $outDir/classes.dex.jar $in`,
+			CommandDeps: []string{
+				"${config.DxCmd}",
+				"${config.SoongZipCmd}",
+				"${config.MergeZipsCmd}",
+			},
+		},
+		"outDir", "dxFlags")
+
 	jarjar = pctx.AndroidStaticRule("jarjar",
 		blueprint.RuleParams{
 			Command:     "${config.JavaCmd} -jar ${config.JarjarCmd} process $rulesFile $in $out",
@@ -420,9 +434,15 @@ func TransformClassesJarToDexJar(ctx android.ModuleContext, outputFile android.W
 
 	outDir := android.PathForModuleOut(ctx, "dex")
 
+	rule := dx
+	desc := "dx"
+	if ctx.AConfig().IsEnvTrue("USE_D8_DESUGAR") {
+		rule = d8
+		desc = "d8"
+	}
 	ctx.Build(pctx, android.BuildParams{
-		Rule:        dx,
-		Description: "dx",
+		Rule:        rule,
+		Description: desc,
 		Output:      outputFile,
 		Input:       classesJar,
 		Args: map[string]string{

java/config/config.go

@@ -106,6 +106,13 @@ func init() {
 			return path.String(), nil
 		}
 	})
+	pctx.VariableFunc("D8Cmd", func(config android.Config) (string, error) {
+		path, err := pctx.HostBinToolPath(config, "d8")
+		if err != nil {
+			return "", err
+		}
+		return path.String(), nil
+	})
 	pctx.VariableFunc("TurbineJar", func(config android.Config) (string, error) {
 		turbine := "turbine.jar"
 		if config.UnbundledBuild() {

java/config/makevars.go

@@ -45,8 +45,15 @@ func makeVarsProvider(ctx android.MakeVarsContext) {
 	ctx.Strict("JAR_ARGS", "${JarArgsCmd}")
 	ctx.Strict("JAVADOC", "${JavadocCmd}")
 	ctx.Strict("COMMON_JDK_FLAGS", "${CommonJdkFlags}")
-	ctx.Strict("DX", "${DxCmd}")
-	ctx.Strict("DX_COMMAND", "${DxCmd} -JXms16M -JXmx2048M")
+
+	if ctx.Config().IsEnvTrue("USE_D8_DESUGAR") {
+		ctx.Strict("DX", "${D8Cmd}")
+		ctx.Strict("DX_COMMAND", "${D8Cmd} -JXms16M -JXmx2048M")
+	} else {
+		ctx.Strict("DX", "${DxCmd}")
+		ctx.Strict("DX_COMMAND", "${DxCmd} -JXms16M -JXmx2048M")
+	}
+
 	ctx.Strict("TURBINE", "${TurbineJar}")
 
 	if ctx.Config().IsEnvTrue("RUN_ERROR_PRONE") {

java/java.go

@@ -671,6 +671,7 @@ func (j *Module) compile(ctx android.ModuleContext, extraSrcJars ...android.Path
 	// Store the list of .java files that was passed to javac
 	j.compiledJavaSrcs = uniqueSrcFiles
 	j.compiledSrcJars = srcJars
+	fullD8 := ctx.AConfig().IsEnvTrue("USE_D8_DESUGAR")
 
 	enable_sharding := false
 	if ctx.Device() && !ctx.Config().IsEnvFalse("TURBINE_ENABLED") {
@@ -793,7 +794,7 @@ func (j *Module) compile(ctx android.ModuleContext, extraSrcJars ...android.Path
 		j.headerJarFile = j.implementationJarFile
 	}
 
-	if ctx.Device() && j.installable() {
+	if !fullD8 && ctx.Device() && j.installable() {
 		outputFile = j.desugar(ctx, flags, outputFile, jarName)
 	}
 
@@ -808,7 +809,11 @@ func (j *Module) compile(ctx android.ModuleContext, extraSrcJars ...android.Path
 	}
 
 	if ctx.Device() && j.installable() {
-		outputFile = j.compileDex(ctx, flags, outputFile, jarName)
+		if fullD8 {
+			outputFile = j.compileDexFullD8(ctx, flags, outputFile, jarName)
+		} else {
+			outputFile = j.compileDex(ctx, flags, outputFile, jarName)
+		}
 		if ctx.Failed() {
 			return
 		}
@@ -896,15 +901,6 @@ func (j *Module) compileDex(ctx android.ModuleContext, flags javaBuilderFlags,
 	classesJar android.Path, jarName string) android.Path {
 
 	dxFlags := j.deviceProperties.Dxflags
-	if false /* emma enabled */ {
-		// If you instrument class files that have local variable debug information in
-		// them emma does not correctly maintain the local variable table.
-		// This will cause an error when you try to convert the class files for Android.
-		// The workaround here is to build different dex file here based on emma switch
-		// then later copy into classes.dex. When emma is on, dx is run with --no-locals
-		// option to remove local variable information
-		dxFlags = append(dxFlags, "--no-locals")
-	}
 
 	if ctx.Config().Getenv("NO_OPTIMIZE_DX") != "" {
 		dxFlags = append(dxFlags, "--no-optimize")
@@ -930,6 +926,51 @@ func (j *Module) compileDex(ctx android.ModuleContext, flags javaBuilderFlags,
 	return javalibJar
 }
 
+func (j *Module) compileDexFullD8(ctx android.ModuleContext, flags javaBuilderFlags,
+	classesJar android.Path, jarName string) android.Path {
+
+	// Translate all the DX flags to D8 ones until all the build files have been migrated
+	// to D8 flags. See: b/69377755
+	var dxFlags []string
+	for _, x := range j.deviceProperties.Dxflags {
+		if x == "--core-library" {
+			continue
+		}
+		if x == "--dex" {
+			continue
+		}
+		if x == "--multi-dex" {
+			continue
+		}
+		if x == "--no-locals" {
+			dxFlags = append(dxFlags, "--release")
+			continue
+		}
+		dxFlags = append(dxFlags, x)
+	}
+
+	if ctx.AConfig().Getenv("NO_OPTIMIZE_DX") != "" {
+		dxFlags = append(dxFlags, "--debug")
+	}
+
+	if ctx.AConfig().Getenv("GENERATE_DEX_DEBUG") != "" {
+		dxFlags = append(dxFlags,
+			"--debug",
+			"--verbose")
+	}
+
+	dxFlags = append(dxFlags, "--min-api "+j.minSdkVersionNumber(ctx))
+
+	flags.dxFlags = strings.Join(dxFlags, " ")
+
+	// Compile classes.jar into classes.dex and then javalib.jar
+	javalibJar := android.PathForModuleOut(ctx, "dex", jarName)
+	TransformClassesJarToDexJar(ctx, javalibJar, classesJar, flags)
+
+	j.dexJarFile = javalibJar
+	return javalibJar
+}
+
 // Returns a sdk version as a string that is guaranteed to be a parseable as a number.  For
 // modules targeting an unreleased SDK (meaning it does not yet have a number) it returns "10000".
 func (j *Module) minSdkVersionNumber(ctx android.ModuleContext) string {