Remove fdoProfileMutator

Add the dependency on the fdo_profile module in afdoTransitionMutator
and read the provider in GenerateAndroidBuildActions.

This relands Ied8fd7b52d5694a3691652318e87b8fe14dda126 with a fix
to use the correct LTO ldflag when an afdo variant doesn't have a
profile.

Bug: 319288033
Bug: 324141705
Test: afdo_test.go
Change-Id: I024ca316cfb565b5fb0251793f05a54ce16cc1cb

4 files changed, 51 insertions, 93 deletions

diff --git a/cc/afdo.go b/cc/afdo.go
index 1e2290069..00b22456f 100644
--- a/cc/afdo.go
+++ b/cc/afdo.go
@@ -21,7 +21,6 @@ import (
 	"android/soong/android"
 
 	"github.com/google/blueprint"
-	"github.com/google/blueprint/proptools"
 )
 
 // This flag needs to be in both CFlags and LdFlags to ensure correct symbol ordering
@@ -32,7 +31,7 @@ type AfdoProperties struct {
 	// automatic feedback-directed optimization using profile data.
 	Afdo bool
 
-	FdoProfilePath *string `blueprint:"mutated"`
+	AfdoDep bool `blueprint:"mutated"`
 }
 
 type afdo struct {
@@ -51,17 +50,32 @@ func (afdo *afdo) begin(ctx BaseModuleContext) {
 }
 
 // afdoEnabled returns true for binaries and shared libraries
-// that set afdo prop to True and there is a profile available
+// that set afdo prop to True.
 func (afdo *afdo) afdoEnabled() bool {
 	return afdo != nil && afdo.Properties.Afdo
 }
 
+func (afdo *afdo) isAfdoCompile(ctx ModuleContext) bool {
+	fdoProfilePath := getFdoProfilePathFromDep(ctx)
+	return !ctx.Host() && (afdo.Properties.Afdo || afdo.Properties.AfdoDep) && (fdoProfilePath != "")
+}
+
+func getFdoProfilePathFromDep(ctx ModuleContext) string {
+	fdoProfileDeps := ctx.GetDirectDepsWithTag(FdoProfileTag)
+	if len(fdoProfileDeps) > 0 && fdoProfileDeps[0] != nil {
+		if info, ok := android.OtherModuleProvider(ctx, fdoProfileDeps[0], FdoProfileProvider); ok {
+			return info.Path.String()
+		}
+	}
+	return ""
+}
+
 func (afdo *afdo) flags(ctx ModuleContext, flags Flags) Flags {
 	if ctx.Host() {
 		return flags
 	}
 
-	if afdo.Properties.Afdo {
+	if afdo.Properties.Afdo || afdo.Properties.AfdoDep {
 		// We use `-funique-internal-linkage-names` to associate profiles to the right internal
 		// functions. This option should be used before generating a profile. Because a profile
 		// generated for a binary without unique names doesn't work well building a binary with
@@ -79,15 +93,15 @@ func (afdo *afdo) flags(ctx ModuleContext, flags Flags) Flags {
 		// TODO(b/266595187): Remove the following feature once it is enabled in LLVM by default.
 		flags.Local.CFlags = append([]string{"-mllvm", "-improved-fs-discriminator=true"}, flags.Local.CFlags...)
 	}
-	if path := afdo.Properties.FdoProfilePath; path != nil {
+	if fdoProfilePath := getFdoProfilePathFromDep(ctx); fdoProfilePath != "" {
 		// The flags are prepended to allow overriding.
-		profileUseFlag := fmt.Sprintf(afdoFlagsFormat, *path)
+		profileUseFlag := fmt.Sprintf(afdoFlagsFormat, fdoProfilePath)
 		flags.Local.CFlags = append([]string{profileUseFlag}, flags.Local.CFlags...)
 		flags.Local.LdFlags = append([]string{profileUseFlag, "-Wl,-mllvm,-no-warn-sample-unused=true"}, flags.Local.LdFlags...)
 
 		// Update CFlagsDeps and LdFlagsDeps so the module is rebuilt
 		// if profileFile gets updated
-		pathForSrc := android.PathForSource(ctx, *path)
+		pathForSrc := android.PathForSource(ctx, fdoProfilePath)
 		flags.CFlagsDeps = append(flags.CFlagsDeps, pathForSrc)
 		flags.LdFlagsDeps = append(flags.LdFlagsDeps, pathForSrc)
 	}
@@ -95,45 +109,18 @@ func (afdo *afdo) flags(ctx ModuleContext, flags Flags) Flags {
 	return flags
 }
 
-// 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) {
-	if !c.Enabled() {
-		return
-	}
-
-	if !c.afdo.afdoEnabled() {
-		return
-	}
-
-	if c.Host() {
-		return
-	}
-
-	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())
-				}
-			}
-		}
+func (a *afdo) addDep(ctx android.BottomUpMutatorContext, fdoProfileTarget string) {
+	if fdoProfileName, err := ctx.DeviceConfig().AfdoProfile(fdoProfileTarget); fdoProfileName != "" && err == nil {
+		ctx.AddFarVariationDependencies(
+			[]blueprint.Variation{
+				{Mutator: "arch", Variation: ctx.Target().ArchVariation()},
+				{Mutator: "os", Variation: "android"},
+			},
+			FdoProfileTag,
+			fdoProfileName)
 	}
 }
 
-var _ FdoProfileMutatorInterface = (*Module)(nil)
-
 func afdoPropagateViaDepTag(tag blueprint.DependencyTag) bool {
 	libTag, isLibTag := tag.(libraryDependencyTag)
 	// Do not recurse down non-static dependencies
@@ -188,27 +175,20 @@ func (a *afdoTransitionMutator) IncomingTransition(ctx android.IncomingTransitio
 }
 
 func (a *afdoTransitionMutator) Mutate(ctx android.BottomUpMutatorContext, variation string) {
-	if variation == "" {
-		return
-	}
-
 	if m, ok := ctx.Module().(*Module); ok && m.afdo != nil {
-		m.Properties.PreventInstall = true
-		m.Properties.HideFromMake = true
-		m.afdo.Properties.Afdo = true
-		if fdoProfileName, err := ctx.DeviceConfig().AfdoProfile(decodeTarget(variation)); 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 {
-					m.afdo.Properties.FdoProfilePath = proptools.StringPtr(info.Path.String())
-				}
+		if variation == "" {
+			// The empty variation is either a module that has enabled AFDO for itself, or the non-AFDO
+			// variant of a dependency.
+			if m.afdo.afdoEnabled() && !(m.static() && !m.staticBinary()) && !m.Host() {
+				m.afdo.addDep(ctx, ctx.ModuleName())
 			}
+		} else {
+			// The non-empty variation is the AFDO variant of a dependency of a module that enabled AFDO
+			// for itself.
+			m.Properties.PreventInstall = true
+			m.Properties.HideFromMake = true
+			m.afdo.Properties.AfdoDep = true
+			m.afdo.addDep(ctx, decodeTarget(variation))
 		}
 	}
 }
diff --git a/cc/cc.go b/cc/cc.go
index 3688e9573..39024aa3c 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -55,7 +55,6 @@ 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).Parallel()
 	})
 
 	ctx.PostDepsMutators(func(ctx android.RegisterMutatorsContext) {
@@ -526,7 +525,7 @@ type ModuleContextIntf interface {
 	selectedStl() string
 	baseModuleName() string
 	getVndkExtendsModuleName() string
-	isAfdoCompile() bool
+	isAfdoCompile(ctx ModuleContext) bool
 	isOrderfileCompile() bool
 	isCfi() bool
 	isFuzzer() bool
@@ -1380,9 +1379,9 @@ func (c *Module) IsVndk() bool {
 	return false
 }
 
-func (c *Module) isAfdoCompile() bool {
+func (c *Module) isAfdoCompile(ctx ModuleContext) bool {
 	if afdo := c.afdo; afdo != nil {
-		return afdo.Properties.FdoProfilePath != nil
+		return afdo.isAfdoCompile(ctx)
 	}
 	return false
 }
@@ -1705,8 +1704,8 @@ func (ctx *moduleContextImpl) isVndk() bool {
 	return ctx.mod.IsVndk()
 }
 
-func (ctx *moduleContextImpl) isAfdoCompile() bool {
-	return ctx.mod.isAfdoCompile()
+func (ctx *moduleContextImpl) isAfdoCompile(mctx ModuleContext) bool {
+	return ctx.mod.isAfdoCompile(mctx)
 }
 
 func (ctx *moduleContextImpl) isOrderfileCompile() bool {
diff --git a/cc/fdo_profile.go b/cc/fdo_profile.go
index 0893da5e0..1a3395773 100644
--- a/cc/fdo_profile.go
+++ b/cc/fdo_profile.go
@@ -43,23 +43,10 @@ type FdoProfileInfo struct {
 }
 
 // FdoProfileProvider is used to provide path to an fdo profile
-var FdoProfileProvider = blueprint.NewMutatorProvider[FdoProfileInfo]("fdo_profile")
-
-// FdoProfileMutatorInterface is the interface implemented by fdo_profile module type
-// module types that can depend on an fdo_profile module
-type FdoProfileMutatorInterface interface {
-	// FdoProfileMutator eithers set or get FdoProfileProvider
-	fdoProfileMutator(ctx android.BottomUpMutatorContext)
-}
-
-var _ FdoProfileMutatorInterface = (*fdoProfile)(nil)
+var FdoProfileProvider = blueprint.NewProvider[FdoProfileInfo]()
 
 // GenerateAndroidBuildActions of fdo_profile does not have any build actions
-func (fp *fdoProfile) GenerateAndroidBuildActions(ctx android.ModuleContext) {}
-
-// FdoProfileMutator sets FdoProfileProvider to fdo_profile module
-// or sets afdo.Properties.FdoProfilePath to path in FdoProfileProvider of the depended fdo_profile
-func (fp *fdoProfile) fdoProfileMutator(ctx android.BottomUpMutatorContext) {
+func (fp *fdoProfile) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	if fp.properties.Profile != nil {
 		path := android.PathForModuleSrc(ctx, *fp.properties.Profile)
 		android.SetProvider(ctx, FdoProfileProvider, FdoProfileInfo{
@@ -68,14 +55,6 @@ func (fp *fdoProfile) fdoProfileMutator(ctx android.BottomUpMutatorContext) {
 	}
 }
 
-// fdoProfileMutator calls the generic fdoProfileMutator function of fdoProfileMutator
-// which is implemented by cc and cc.FdoProfile
-func fdoProfileMutator(ctx android.BottomUpMutatorContext) {
-	if f, ok := ctx.Module().(FdoProfileMutatorInterface); ok {
-		f.fdoProfileMutator(ctx)
-	}
-}
-
 func FdoProfileFactory() android.Module {
 	m := &fdoProfile{}
 	m.AddProperties(&m.properties)
diff --git a/cc/lto.go b/cc/lto.go
index b2b45706d..05fa8eea5 100644
--- a/cc/lto.go
+++ b/cc/lto.go
@@ -100,7 +100,7 @@ func (lto *lto) begin(ctx BaseModuleContext) {
 	lto.Properties.LtoEnabled = ltoEnabled
 }
 
-func (lto *lto) flags(ctx BaseModuleContext, flags Flags) Flags {
+func (lto *lto) flags(ctx ModuleContext, flags Flags) Flags {
 	// TODO(b/131771163): CFI and Fuzzer controls LTO flags by themselves.
 	// This has be checked late because these properties can be mutated.
 	if ctx.isCfi() || ctx.isFuzzer() {
@@ -139,7 +139,7 @@ func (lto *lto) flags(ctx BaseModuleContext, flags Flags) Flags {
 		// Reduce the inlining threshold for a better balance of binary size and
 		// performance.
 		if !ctx.Darwin() {
-			if ctx.isAfdoCompile() {
+			if ctx.isAfdoCompile(ctx) {
 				ltoLdFlags = append(ltoLdFlags, "-Wl,-plugin-opt,-import-instr-limit=40")
 			} else {
 				ltoLdFlags = append(ltoLdFlags, "-Wl,-plugin-opt,-import-instr-limit=5")