Convert AFDO mutators to TransitionMutator

Convert afdoDepsMutator and afdoMutator to a TransitionMutator as a
step towards variants-on-demand.

This relands Ib05845455ccf43a07b3915a0d7b0a95896062f13 with a fix
to maintain the current behavior of not using AFDO variants for
dependencies of the linker static binary.

Bug: 319288033
Bug: 324141705
Test: afdo_test.go
Change-Id: I76e30021173fc5b7e9e1fa826039776eb3dc7b6e

android/config.go

@@ -1466,18 +1466,18 @@ func (c *deviceConfig) PgoAdditionalProfileDirs() []string {
 }
 
 // AfdoProfile returns fully qualified path associated to the given module name
-func (c *deviceConfig) AfdoProfile(name string) (*string, error) {
+func (c *deviceConfig) AfdoProfile(name string) (string, error) {
 	for _, afdoProfile := range c.config.productVariables.AfdoProfiles {
 		split := strings.Split(afdoProfile, ":")
 		if len(split) != 3 {
-			return nil, fmt.Errorf("AFDO_PROFILES has invalid value: %s. "+
+			return "", fmt.Errorf("AFDO_PROFILES has invalid value: %s. "+
 				"The expected format is <module>:<fully-qualified-path-to-fdo_profile>", afdoProfile)
 		}
 		if split[0] == name {
-			return proptools.StringPtr(strings.Join([]string{split[1], split[2]}, ":")), nil
+			return strings.Join([]string{split[1], split[2]}, ":"), nil
 		}
 	}
-	return nil, nil
+	return "", nil
 }
 
 func (c *deviceConfig) VendorSepolicyDirs() []string {

cc/afdo.go

@@ -27,23 +27,12 @@ import (
 // This flag needs to be in both CFlags and LdFlags to ensure correct symbol ordering
 const afdoFlagsFormat = "-fprofile-sample-use=%s -fprofile-sample-accurate"
 
-func recordMissingAfdoProfileFile(ctx android.BaseModuleContext, missing string) {
-	getNamedMapForConfig(ctx.Config(), modulesMissingProfileFileKey).Store(missing, true)
-}
-
-type afdoRdep struct {
-	VariationName *string
-	ProfilePath   *string
-}
-
 type AfdoProperties struct {
 	// Afdo allows developers self-service enroll for
 	// automatic feedback-directed optimization using profile data.
 	Afdo bool
 
 	FdoProfilePath *string `blueprint:"mutated"`
-
-	AfdoRDeps []afdoRdep `blueprint:"mutated"`
 }
 
 type afdo struct {
@@ -106,29 +95,6 @@ func (afdo *afdo) flags(ctx ModuleContext, flags Flags) Flags {
 	return flags
 }
 
-func (afdo *afdo) addDep(ctx BaseModuleContext, actx android.BottomUpMutatorContext) {
-	if ctx.Host() {
-		return
-	}
-
-	if ctx.static() && !ctx.staticBinary() {
-		return
-	}
-
-	if c, ok := ctx.Module().(*Module); ok && c.Enabled() {
-		if fdoProfileName, err := actx.DeviceConfig().AfdoProfile(actx.ModuleName()); fdoProfileName != nil && err == nil {
-			actx.AddFarVariationDependencies(
-				[]blueprint.Variation{
-					{Mutator: "arch", Variation: actx.Target().ArchVariation()},
-					{Mutator: "os", Variation: "android"},
-				},
-				FdoProfileTag,
-				[]string{*fdoProfileName}...,
-			)
-		}
-	}
-}
-
 // FdoProfileMutator reads the FdoProfileProvider from a direct dep with FdoProfileTag
 // assigns FdoProfileInfo.Path to the FdoProfilePath mutated property
 func (c *Module) fdoProfileMutator(ctx android.BottomUpMutatorContext) {
@@ -140,95 +106,108 @@ func (c *Module) fdoProfileMutator(ctx android.BottomUpMutatorContext) {
 		return
 	}
 
-	ctx.VisitDirectDepsWithTag(FdoProfileTag, func(m android.Module) {
+	if c.Host() {
-		if info, ok := android.OtherModuleProvider(ctx, m, FdoProfileProvider); ok {
+		return
-			c.afdo.Properties.FdoProfilePath = proptools.StringPtr(info.Path.String())
+	}
+
+	if c.static() && !c.staticBinary() {
+		return
+	}
+
+	if c, ok := ctx.Module().(*Module); ok && c.Enabled() {
+		if fdoProfileName, err := ctx.DeviceConfig().AfdoProfile(ctx.ModuleName()); fdoProfileName != "" && err == nil {
+			deps := ctx.AddFarVariationDependencies(
+				[]blueprint.Variation{
+					{Mutator: "arch", Variation: ctx.Target().ArchVariation()},
+					{Mutator: "os", Variation: "android"},
+				},
+				FdoProfileTag,
+				fdoProfileName)
+			if len(deps) > 0 && deps[0] != nil {
+				if info, ok := android.OtherModuleProvider(ctx, deps[0], FdoProfileProvider); ok {
+					c.afdo.Properties.FdoProfilePath = proptools.StringPtr(info.Path.String())
+				}
+			}
 		}
-	})
+	}
 }
 
 var _ FdoProfileMutatorInterface = (*Module)(nil)
 
-// Propagate afdo requirements down from binaries and shared libraries
+func afdoPropagateViaDepTag(tag blueprint.DependencyTag) bool {
-func afdoDepsMutator(mctx android.TopDownMutatorContext) {
+	libTag, isLibTag := tag.(libraryDependencyTag)
-	if mctx.Host() {
+	// Do not recurse down non-static dependencies
-		return
+	if isLibTag {
-	}
+		return libTag.static()
-
+	} else {
-	if m, ok := mctx.Module().(*Module); ok && m.afdo.afdoEnabled() {
+		return tag == objDepTag || tag == reuseObjTag || tag == staticVariantTag
-		path := m.afdo.Properties.FdoProfilePath
-		mctx.WalkDeps(func(dep android.Module, parent android.Module) bool {
-			tag := mctx.OtherModuleDependencyTag(dep)
-			libTag, isLibTag := tag.(libraryDependencyTag)
-
-			// Do not recurse down non-static dependencies
-			if isLibTag {
-				if !libTag.static() {
-					return false
-				}
-			} else {
-				if tag != objDepTag && tag != reuseObjTag {
-					return false
-				}
-			}
-
-			if dep, ok := dep.(*Module); ok {
-				dep.afdo.Properties.AfdoRDeps = append(
-					dep.afdo.Properties.AfdoRDeps,
-					afdoRdep{
-						VariationName: proptools.StringPtr(encodeTarget(m.Name())),
-						ProfilePath:   path,
-					},
-				)
-			}
-
-			return true
-		})
 	}
 }
 
-// Create afdo variants for modules that need them
+// afdoTransitionMutator creates afdo variants of cc modules.
-func afdoMutator(mctx android.BottomUpMutatorContext) {
+type afdoTransitionMutator struct{}
-	if mctx.Host() {
+
+func (a *afdoTransitionMutator) Split(ctx android.BaseModuleContext) []string {
+	return []string{""}
+}
+
+func (a *afdoTransitionMutator) OutgoingTransition(ctx android.OutgoingTransitionContext, sourceVariation string) string {
+	if ctx.Host() {
+		return ""
+	}
+
+	if m, ok := ctx.Module().(*Module); ok && m.afdo != nil {
+		if !afdoPropagateViaDepTag(ctx.DepTag()) {
+			return ""
+		}
+
+		if sourceVariation != "" {
+			return sourceVariation
+		}
+
+		if !m.afdo.afdoEnabled() {
+			return ""
+		}
+
+		// TODO(b/324141705): this is designed to prevent propagating AFDO from static libraries that have afdo: true set, but
+		//  it should be m.static() && !m.staticBinary() so that static binaries use AFDO variants of dependencies.
+		if m.static() {
+			return ""
+		}
+
+		return encodeTarget(ctx.Module().Name())
+	}
+	return ""
+}
+
+func (a *afdoTransitionMutator) IncomingTransition(ctx android.IncomingTransitionContext, incomingVariation string) string {
+	if m, ok := ctx.Module().(*Module); ok && m.afdo != nil {
+		return incomingVariation
+	}
+	return ""
+}
+
+func (a *afdoTransitionMutator) Mutate(ctx android.BottomUpMutatorContext, variation string) {
+	if variation == "" {
 		return
 	}
 
-	if m, ok := mctx.Module().(*Module); ok && m.afdo != nil {
+	if m, ok := ctx.Module().(*Module); ok && m.afdo != nil {
-		if !m.static() && m.afdo.Properties.Afdo {
+		m.Properties.PreventInstall = true
-			mctx.SetDependencyVariation(encodeTarget(m.Name()))
+		m.Properties.HideFromMake = true
-			return
+		m.afdo.Properties.Afdo = true
-		}
+		if fdoProfileName, err := ctx.DeviceConfig().AfdoProfile(decodeTarget(variation)); fdoProfileName != "" && err == nil {
-
+			deps := ctx.AddFarVariationDependencies(
-		variationNames := []string{""}
+				[]blueprint.Variation{
-
+					{Mutator: "arch", Variation: ctx.Target().ArchVariation()},
-		variantNameToProfilePath := make(map[string]*string)
+					{Mutator: "os", Variation: "android"},
-
+				},
-		for _, afdoRDep := range m.afdo.Properties.AfdoRDeps {
+				FdoProfileTag,
-			variantName := *afdoRDep.VariationName
+				fdoProfileName)
-			// An rdep can be set twice in AfdoRDeps because there can be
+			if len(deps) > 0 && deps[0] != nil {
-			// more than one path from an afdo-enabled module to
+				if info, ok := android.OtherModuleProvider(ctx, deps[0], FdoProfileProvider); ok {
-			// a static dep such as
+					m.afdo.Properties.FdoProfilePath = proptools.StringPtr(info.Path.String())
-			// afdo_enabled_foo -> static_bar ----> static_baz
-			//                   \                      ^
-			//                    ----------------------|
-			// We only need to create one variant per unique rdep
-			if _, exists := variantNameToProfilePath[variantName]; !exists {
-				variationNames = append(variationNames, variantName)
-				variantNameToProfilePath[variantName] = afdoRDep.ProfilePath
-			}
-		}
-
-		if len(variationNames) > 1 {
-			modules := mctx.CreateVariations(variationNames...)
-			for i, name := range variationNames {
-				if name == "" {
-					continue
 				}
-				variation := modules[i].(*Module)
-				variation.Properties.PreventInstall = true
-				variation.Properties.HideFromMake = true
-				variation.afdo.Properties.Afdo = true
-				variation.afdo.Properties.FdoProfilePath = variantNameToProfilePath[name]
 			}
 		}
 	}

cc/cc.go

@@ -55,7 +55,7 @@ func RegisterCCBuildComponents(ctx android.RegistrationContext) {
 		ctx.BottomUp("test_per_src", TestPerSrcMutator).Parallel()
 		ctx.BottomUp("version", versionMutator).Parallel()
 		ctx.BottomUp("begin", BeginMutator).Parallel()
-		ctx.BottomUp("fdo_profile", fdoProfileMutator)
+		ctx.BottomUp("fdo_profile", fdoProfileMutator).Parallel()
 	})
 
 	ctx.PostDepsMutators(func(ctx android.RegisterMutatorsContext) {
@@ -70,8 +70,7 @@ func RegisterCCBuildComponents(ctx android.RegistrationContext) {
 
 		ctx.Transition("coverage", &coverageTransitionMutator{})
 
-		ctx.TopDown("afdo_deps", afdoDepsMutator)
+		ctx.Transition("afdo", &afdoTransitionMutator{})
-		ctx.BottomUp("afdo", afdoMutator).Parallel()
 
 		ctx.Transition("orderfile", &orderfileTransitionMutator{})
 
@@ -2351,10 +2350,6 @@ func (c *Module) beginMutator(actx android.BottomUpMutatorContext) {
 	}
 	ctx.ctx = ctx
 
-	if !actx.Host() || !ctx.static() || ctx.staticBinary() {
-		c.afdo.addDep(ctx, actx)
-	}
-
 	c.begin(ctx)
 }
 

rust/afdo.go

@@ -44,14 +44,14 @@ func (afdo *afdo) addDep(ctx BaseModuleContext, actx android.BottomUpMutatorCont
 		if err != nil {
 			ctx.ModuleErrorf("%s", err.Error())
 		}
-		if fdoProfileName != nil {
+		if fdoProfileName != "" {
 			actx.AddFarVariationDependencies(
 				[]blueprint.Variation{
 					{Mutator: "arch", Variation: actx.Target().ArchVariation()},
 					{Mutator: "os", Variation: "android"},
 				},
 				cc.FdoProfileTag,
-				[]string{*fdoProfileName}...,
+				[]string{fdoProfileName}...,
 			)
 		}
 	}