Merge changes from topic "remove-non-parallel-mutator" into main

* changes:
  Remove MutatorHandle.Parallel()
  Fix TestFinalDepsPhase for parallel mutator

20 files changed, 63 insertions, 66 deletions

diff --git a/android/defaults.go b/android/defaults.go
index 8fe28796e..510ebe0a2 100644
--- a/android/defaults.go
+++ b/android/defaults.go
@@ -273,8 +273,8 @@ func (defaultable *DefaultableModuleBase) applyDefaultProperties(ctx BottomUpMut
 }
 
 func RegisterDefaultsPreArchMutators(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("defaults_deps", defaultsDepsMutator).Parallel()
-	ctx.BottomUp("defaults", defaultsMutator).Parallel().UsesCreateModule()
+	ctx.BottomUp("defaults_deps", defaultsDepsMutator)
+	ctx.BottomUp("defaults", defaultsMutator).UsesCreateModule()
 }
 
 func defaultsDepsMutator(ctx BottomUpMutatorContext) {
diff --git a/android/licenses.go b/android/licenses.go
index be1eedeff..949d67845 100644
--- a/android/licenses.go
+++ b/android/licenses.go
@@ -106,19 +106,19 @@ func moduleToPackageDefaultLicensesMap(config Config) *sync.Map {
 //
 // This goes before defaults expansion so the defaults can pick up the package default.
 func RegisterLicensesPackageMapper(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("licensesPackageMapper", licensesPackageMapper).Parallel()
+	ctx.BottomUp("licensesPackageMapper", licensesPackageMapper)
 }
 
 // Registers the function that gathers the license dependencies for each module.
 //
 // This goes after defaults expansion so that it can pick up default licenses and before visibility enforcement.
 func RegisterLicensesPropertyGatherer(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("licensesPropertyGatherer", licensesPropertyGatherer).Parallel()
+	ctx.BottomUp("licensesPropertyGatherer", licensesPropertyGatherer)
 }
 
 // Registers the function that verifies the licenses and license_kinds dependency types for each module.
 func RegisterLicensesDependencyChecker(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("licensesPropertyChecker", licensesDependencyChecker).Parallel()
+	ctx.BottomUp("licensesPropertyChecker", licensesDependencyChecker)
 }
 
 // Maps each package to its default applicable licenses.
diff --git a/android/mutator.go b/android/mutator.go
index 0da3ec7d0..6bd2e60b8 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -211,10 +211,7 @@ type BottomUpMutatorContext interface {
 	// AddDependency adds a dependency to the given module.  It returns a slice of modules for each
 	// dependency (some entries may be nil).
 	//
-	// If the mutator is parallel (see MutatorHandle.Parallel), this method will pause until the
-	// new dependencies have had the current mutator called on them.  If the mutator is not
-	// parallel this method does not affect the ordering of the current mutator pass, but will
-	// be ordered correctly for all future mutator passes.
+	// This method will pause until the new dependencies have had the current mutator called on them.
 	AddDependency(module blueprint.Module, tag blueprint.DependencyTag, name ...string) []blueprint.Module
 
 	// AddReverseDependency adds a dependency from the destination to the given module.
@@ -230,10 +227,7 @@ type BottomUpMutatorContext interface {
 	// each dependency (some entries may be nil).  A variant of the dependency must exist that matches
 	// all the non-local variations of the current module, plus the variations argument.
 	//
-	// If the mutator is parallel (see MutatorHandle.Parallel), this method will pause until the
-	// new dependencies have had the current mutator called on them.  If the mutator is not
-	// parallel this method does not affect the ordering of the current mutator pass, but will
-	// be ordered correctly for all future mutator passes.
+	// This method will pause until the new dependencies have had the current mutator called on them.
 	AddVariationDependencies(variations []blueprint.Variation, tag blueprint.DependencyTag, names ...string) []blueprint.Module
 
 	// AddReverseVariationDependency adds a dependency from the named module to the current
@@ -256,10 +250,7 @@ type BottomUpMutatorContext interface {
 	// Unlike AddVariationDependencies, the variations of the current module are ignored - the
 	// dependency only needs to match the supplied variations.
 	//
-	// If the mutator is parallel (see MutatorHandle.Parallel), this method will pause until the
-	// new dependencies have had the current mutator called on them.  If the mutator is not
-	// parallel this method does not affect the ordering of the current mutator pass, but will
-	// be ordered correctly for all future mutator passes.
+	// This method will pause until the new dependencies have had the current mutator called on them.
 	AddFarVariationDependencies([]blueprint.Variation, blueprint.DependencyTag, ...string) []blueprint.Module
 
 	// ReplaceDependencies finds all the variants of the module with the specified name, then
@@ -628,9 +619,6 @@ func (mutator *mutator) register(ctx *Context) {
 	}
 
 	// Forward booleans set on the MutatorHandle to the blueprint.MutatorHandle.
-	if mutator.parallel {
-		handle.Parallel()
-	}
 	if mutator.usesRename {
 		handle.UsesRename()
 	}
@@ -655,6 +643,7 @@ type MutatorHandle interface {
 	// Parallel sets the mutator to visit modules in parallel while maintaining ordering.  Calling any
 	// method on the mutator context is thread-safe, but the mutator must handle synchronization
 	// for any modifications to global state or any modules outside the one it was invoked on.
+	// Deprecated: all Mutators are parallel by default.
 	Parallel() MutatorHandle
 
 	// UsesRename marks the mutator as using the BottomUpMutatorContext.Rename method, which prevents
@@ -683,7 +672,6 @@ type MutatorHandle interface {
 }
 
 func (mutator *mutator) Parallel() MutatorHandle {
-	mutator.parallel = true
 	return mutator
 }
 
@@ -718,7 +706,7 @@ func (mutator *mutator) MutatesGlobalState() MutatorHandle {
 }
 
 func RegisterComponentsMutator(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("component-deps", componentDepsMutator).Parallel()
+	ctx.BottomUp("component-deps", componentDepsMutator)
 }
 
 // A special mutator that runs just prior to the deps mutator to allow the dependencies
@@ -736,7 +724,7 @@ func depsMutator(ctx BottomUpMutatorContext) {
 }
 
 func registerDepsMutator(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("deps", depsMutator).Parallel().UsesReverseDependencies()
+	ctx.BottomUp("deps", depsMutator).UsesReverseDependencies()
 }
 
 // android.topDownMutatorContext either has to embed blueprint.TopDownMutatorContext, in which case every method that
diff --git a/android/mutator_test.go b/android/mutator_test.go
index 33fca9e8b..1d5f89042 100644
--- a/android/mutator_test.go
+++ b/android/mutator_test.go
@@ -17,6 +17,8 @@ package android
 import (
 	"fmt"
 	"strings"
+	"sync"
+	"sync/atomic"
 	"testing"
 
 	"github.com/google/blueprint"
@@ -220,7 +222,7 @@ func TestFinalDepsPhase(t *testing.T) {
 		}
 	`
 
-	finalGot := map[string]int{}
+	finalGot := sync.Map{}
 
 	GroupFixturePreparers(
 		FixtureRegisterWithContext(func(ctx RegistrationContext) {
@@ -251,9 +253,11 @@ func TestFinalDepsPhase(t *testing.T) {
 					}
 				})
 				ctx.BottomUp("final", func(ctx BottomUpMutatorContext) {
-					finalGot[ctx.Module().String()] += 1
+					counter, _ := finalGot.LoadOrStore(ctx.Module().String(), &atomic.Int64{})
+					counter.(*atomic.Int64).Add(1)
 					ctx.VisitDirectDeps(func(mod Module) {
-						finalGot[fmt.Sprintf("%s -> %s", ctx.Module().String(), mod)] += 1
+						counter, _ := finalGot.LoadOrStore(fmt.Sprintf("%s -> %s", ctx.Module().String(), mod), &atomic.Int64{})
+						counter.(*atomic.Int64).Add(1)
 					})
 				})
 			})
@@ -276,7 +280,13 @@ func TestFinalDepsPhase(t *testing.T) {
 		"foo{variant:b} -> common_dep_2{variant:a}": 1,
 	}
 
-	AssertDeepEquals(t, "final", finalWant, finalGot)
+	finalGotMap := make(map[string]int)
+	finalGot.Range(func(k, v any) bool {
+		finalGotMap[k.(string)] = int(v.(*atomic.Int64).Load())
+		return true
+	})
+
+	AssertDeepEquals(t, "final", finalWant, finalGotMap)
 }
 
 func TestTransitionMutatorInFinalDeps(t *testing.T) {
diff --git a/android/namespace.go b/android/namespace.go
index 866d12594..8b3ebc4d5 100644
--- a/android/namespace.go
+++ b/android/namespace.go
@@ -457,7 +457,7 @@ func NamespaceFactory() Module {
 }
 
 func RegisterNamespaceMutator(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("namespace_deps", namespaceMutator).Parallel().MutatesGlobalState()
+	ctx.BottomUp("namespace_deps", namespaceMutator).MutatesGlobalState()
 }
 
 func namespaceMutator(ctx BottomUpMutatorContext) {
diff --git a/android/neverallow.go b/android/neverallow.go
index e135f5780..e93763b7b 100644
--- a/android/neverallow.go
+++ b/android/neverallow.go
@@ -44,7 +44,7 @@ import (
 // - it has none of the "Without" properties matched (same rules as above)
 
 func registerNeverallowMutator(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("neverallow", neverallowMutator).Parallel()
+	ctx.BottomUp("neverallow", neverallowMutator)
 }
 
 var neverallows = []Rule{}
diff --git a/android/override_module.go b/android/override_module.go
index d844da616..50ddc9b35 100644
--- a/android/override_module.go
+++ b/android/override_module.go
@@ -234,18 +234,18 @@ func (b *OverridableModuleBase) OverridablePropertiesDepsMutator(ctx BottomUpMut
 // Mutators for override/overridable modules. All the fun happens in these functions. It is critical
 // to keep them in this order and not put any order mutators between them.
 func RegisterOverridePostDepsMutators(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("override_deps", overrideModuleDepsMutator).Parallel().MutatesDependencies() // modifies deps via addOverride
+	ctx.BottomUp("override_deps", overrideModuleDepsMutator).MutatesDependencies() // modifies deps via addOverride
 	ctx.Transition("override", &overrideTransitionMutator{})
-	ctx.BottomUp("override_apply", overrideApplyMutator).Parallel().MutatesDependencies()
+	ctx.BottomUp("override_apply", overrideApplyMutator).MutatesDependencies()
 	// overridableModuleDepsMutator calls OverridablePropertiesDepsMutator so that overridable modules can
 	// add deps from overridable properties.
-	ctx.BottomUp("overridable_deps", overridableModuleDepsMutator).Parallel()
+	ctx.BottomUp("overridable_deps", overridableModuleDepsMutator)
 	// Because overridableModuleDepsMutator is run after PrebuiltPostDepsMutator,
 	// prebuilt's ReplaceDependencies doesn't affect to those deps added by overridable properties.
 	// By running PrebuiltPostDepsMutator again after overridableModuleDepsMutator, deps via overridable properties
 	// can be replaced with prebuilts.
-	ctx.BottomUp("replace_deps_on_prebuilts_for_overridable_deps_again", PrebuiltPostDepsMutator).Parallel().UsesReplaceDependencies()
-	ctx.BottomUp("replace_deps_on_override", replaceDepsOnOverridingModuleMutator).Parallel().UsesReplaceDependencies()
+	ctx.BottomUp("replace_deps_on_prebuilts_for_overridable_deps_again", PrebuiltPostDepsMutator).UsesReplaceDependencies()
+	ctx.BottomUp("replace_deps_on_override", replaceDepsOnOverridingModuleMutator).UsesReplaceDependencies()
 }
 
 type overrideBaseDependencyTag struct {
diff --git a/android/path_properties.go b/android/path_properties.go
index 6210aee91..d80a8ed13 100644
--- a/android/path_properties.go
+++ b/android/path_properties.go
@@ -27,7 +27,7 @@ import (
 // to the output file of the referenced module.
 
 func registerPathDepsMutator(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("pathdeps", pathDepsMutator).Parallel()
+	ctx.BottomUp("pathdeps", pathDepsMutator)
 }
 
 // The pathDepsMutator automatically adds dependencies on any module that is listed with the
diff --git a/android/prebuilt.go b/android/prebuilt.go
index 0b0c517ca..19f12f035 100644
--- a/android/prebuilt.go
+++ b/android/prebuilt.go
@@ -400,13 +400,13 @@ func PrebuiltGetPreferred(ctx BaseModuleContext, module Module) Module {
 }
 
 func RegisterPrebuiltsPreArchMutators(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("prebuilt_rename", PrebuiltRenameMutator).Parallel().UsesRename()
+	ctx.BottomUp("prebuilt_rename", PrebuiltRenameMutator).UsesRename()
 }
 
 func RegisterPrebuiltsPostDepsMutators(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("prebuilt_source", PrebuiltSourceDepsMutator).Parallel().UsesReverseDependencies()
-	ctx.BottomUp("prebuilt_select", PrebuiltSelectModuleMutator).Parallel()
-	ctx.BottomUp("prebuilt_postdeps", PrebuiltPostDepsMutator).Parallel().UsesReplaceDependencies()
+	ctx.BottomUp("prebuilt_source", PrebuiltSourceDepsMutator).UsesReverseDependencies()
+	ctx.BottomUp("prebuilt_select", PrebuiltSelectModuleMutator)
+	ctx.BottomUp("prebuilt_postdeps", PrebuiltPostDepsMutator).UsesReplaceDependencies()
 }
 
 // Returns the name of the source module corresponding to a prebuilt module
diff --git a/android/register.go b/android/register.go
index 94d875d19..bb1ead73c 100644
--- a/android/register.go
+++ b/android/register.go
@@ -92,7 +92,6 @@ type mutator struct {
 	topDownMutator    blueprint.TopDownMutator
 	transitionMutator blueprint.TransitionMutator
 
-	parallel                bool
 	usesRename              bool
 	usesReverseDependencies bool
 	usesReplaceDependencies bool
diff --git a/android/variable.go b/android/variable.go
index 4210f6720..73c0d0e6c 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -29,7 +29,7 @@ func init() {
 
 func registerVariableBuildComponents(ctx RegistrationContext) {
 	ctx.PreDepsMutators(func(ctx RegisterMutatorsContext) {
-		ctx.BottomUp("variable", VariableMutator).Parallel()
+		ctx.BottomUp("variable", VariableMutator)
 	})
 }
 
diff --git a/android/visibility.go b/android/visibility.go
index 61f220026..cee465e8c 100644
--- a/android/visibility.go
+++ b/android/visibility.go
@@ -268,7 +268,7 @@ func registerVisibilityMutators(ctx RegistrationContext) {
 // The rule checker needs to be registered before defaults expansion to correctly check that
 // //visibility:xxx isn't combined with other packages in the same list in any one module.
 func RegisterVisibilityRuleChecker(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("visibilityRuleChecker", visibilityRuleChecker).Parallel()
+	ctx.BottomUp("visibilityRuleChecker", visibilityRuleChecker)
 }
 
 // Registers the function that gathers the visibility rules for each module.
@@ -278,12 +278,12 @@ func RegisterVisibilityRuleChecker(ctx RegisterMutatorsContext) {
 // the complete visibility lists from flat lists and after the package info is gathered to ensure
 // that default_visibility is available.
 func RegisterVisibilityRuleGatherer(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("visibilityRuleGatherer", visibilityRuleGatherer).Parallel()
+	ctx.BottomUp("visibilityRuleGatherer", visibilityRuleGatherer)
 }
 
 // This must be registered after the deps have been resolved.
 func RegisterVisibilityRuleEnforcer(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("visibilityRuleEnforcer", visibilityRuleEnforcer).Parallel()
+	ctx.BottomUp("visibilityRuleEnforcer", visibilityRuleEnforcer)
 }
 
 // Checks the per-module visibility rule lists before defaults expansion.
diff --git a/apex/apex.go b/apex/apex.go
index 6bb2a1a5b..30b16eec2 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -55,20 +55,20 @@ func registerApexBuildComponents(ctx android.RegistrationContext) {
 }
 
 func RegisterPreDepsMutators(ctx android.RegisterMutatorsContext) {
-	ctx.BottomUp("apex_vndk_deps", apexVndkDepsMutator).Parallel().UsesReverseDependencies()
+	ctx.BottomUp("apex_vndk_deps", apexVndkDepsMutator).UsesReverseDependencies()
 }
 
 func RegisterPostDepsMutators(ctx android.RegisterMutatorsContext) {
-	ctx.TopDown("apex_info", apexInfoMutator).Parallel()
-	ctx.BottomUp("apex_unique", apexUniqueVariationsMutator).Parallel()
-	ctx.BottomUp("apex_test_for_deps", apexTestForDepsMutator).Parallel()
-	ctx.BottomUp("apex_test_for", apexTestForMutator).Parallel()
+	ctx.TopDown("apex_info", apexInfoMutator)
+	ctx.BottomUp("apex_unique", apexUniqueVariationsMutator)
+	ctx.BottomUp("apex_test_for_deps", apexTestForDepsMutator)
+	ctx.BottomUp("apex_test_for", apexTestForMutator)
 	// Run mark_platform_availability before the apexMutator as the apexMutator needs to know whether
 	// it should create a platform variant.
-	ctx.BottomUp("mark_platform_availability", markPlatformAvailability).Parallel()
+	ctx.BottomUp("mark_platform_availability", markPlatformAvailability)
 	ctx.Transition("apex", &apexTransitionMutator{})
-	ctx.BottomUp("apex_directly_in_any", apexDirectlyInAnyMutator).Parallel().MutatesDependencies()
-	ctx.BottomUp("apex_dcla_deps", apexDCLADepsMutator).Parallel()
+	ctx.BottomUp("apex_directly_in_any", apexDirectlyInAnyMutator).MutatesDependencies()
+	ctx.BottomUp("apex_dcla_deps", apexDCLADepsMutator)
 }
 
 type apexBundleProperties struct {
diff --git a/cc/cc.go b/cc/cc.go
index 3bc9635cd..9c514eeb7 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -48,10 +48,10 @@ func RegisterCCBuildComponents(ctx android.RegistrationContext) {
 
 	ctx.PreDepsMutators(func(ctx android.RegisterMutatorsContext) {
 		ctx.Transition("sdk", &sdkTransitionMutator{})
-		ctx.BottomUp("llndk", llndkMutator).Parallel()
+		ctx.BottomUp("llndk", llndkMutator)
 		ctx.Transition("link", &linkageTransitionMutator{})
 		ctx.Transition("version", &versionTransitionMutator{})
-		ctx.BottomUp("begin", BeginMutator).Parallel()
+		ctx.BottomUp("begin", BeginMutator)
 	})
 
 	ctx.PostDepsMutators(func(ctx android.RegisterMutatorsContext) {
@@ -59,8 +59,8 @@ func RegisterCCBuildComponents(ctx android.RegistrationContext) {
 			san.registerMutators(ctx)
 		}
 
-		ctx.BottomUp("sanitize_runtime_deps", sanitizerRuntimeDepsMutator).Parallel()
-		ctx.BottomUp("sanitize_runtime", sanitizerRuntimeMutator).Parallel()
+		ctx.BottomUp("sanitize_runtime_deps", sanitizerRuntimeDepsMutator)
+		ctx.BottomUp("sanitize_runtime", sanitizerRuntimeMutator)
 
 		ctx.Transition("fuzz", &fuzzTransitionMutator{})
 
@@ -72,8 +72,8 @@ func RegisterCCBuildComponents(ctx android.RegistrationContext) {
 
 		ctx.Transition("lto", &ltoTransitionMutator{})
 
-		ctx.BottomUp("check_linktype", checkLinkTypeMutator).Parallel()
-		ctx.BottomUp("double_loadable", checkDoubleLoadableLibraries).Parallel()
+		ctx.BottomUp("check_linktype", checkLinkTypeMutator)
+		ctx.BottomUp("double_loadable", checkDoubleLoadableLibraries)
 	})
 
 	ctx.PostApexMutators(func(ctx android.RegisterMutatorsContext) {
diff --git a/cc/sanitize.go b/cc/sanitize.go
index 498ef7c54..118580edd 100644
--- a/cc/sanitize.go
+++ b/cc/sanitize.go
@@ -176,7 +176,7 @@ func (t SanitizerType) registerMutators(ctx android.RegisterMutatorsContext) {
 	switch t {
 	case cfi, Hwasan, Asan, tsan, Fuzzer, scs, Memtag_stack:
 		sanitizer := &sanitizerSplitMutator{t}
-		ctx.BottomUp(t.variationName()+"_markapexes", sanitizer.markSanitizableApexesMutator).Parallel()
+		ctx.BottomUp(t.variationName()+"_markapexes", sanitizer.markSanitizableApexesMutator)
 		ctx.Transition(t.variationName(), sanitizer)
 	case Memtag_heap, Memtag_globals, intOverflow:
 		// do nothing
diff --git a/genrule/genrule.go b/genrule/genrule.go
index 8721f15c2..c029167d0 100644
--- a/genrule/genrule.go
+++ b/genrule/genrule.go
@@ -63,7 +63,7 @@ func RegisterGenruleBuildComponents(ctx android.RegistrationContext) {
 	ctx.RegisterModuleType("genrule", GenRuleFactory)
 
 	ctx.FinalDepsMutators(func(ctx android.RegisterMutatorsContext) {
-		ctx.BottomUp("genrule_tool_deps", toolDepsMutator).Parallel()
+		ctx.BottomUp("genrule_tool_deps", toolDepsMutator)
 	})
 }
 
diff --git a/java/bootclasspath.go b/java/bootclasspath.go
index 029f6f623..3413cf350 100644
--- a/java/bootclasspath.go
+++ b/java/bootclasspath.go
@@ -29,7 +29,7 @@ func init() {
 
 func registerBootclasspathBuildComponents(ctx android.RegistrationContext) {
 	ctx.FinalDepsMutators(func(ctx android.RegisterMutatorsContext) {
-		ctx.BottomUp("bootclasspath_deps", bootclasspathDepsMutator).Parallel()
+		ctx.BottomUp("bootclasspath_deps", bootclasspathDepsMutator)
 	})
 }
 
diff --git a/java/dexpreopt_bootjars.go b/java/dexpreopt_bootjars.go
index 14e201a16..8c60d2399 100644
--- a/java/dexpreopt_bootjars.go
+++ b/java/dexpreopt_bootjars.go
@@ -465,7 +465,7 @@ func RegisterDexpreoptBootJarsComponents(ctx android.RegistrationContext) {
 	ctx.RegisterParallelSingletonModuleType("dex_bootjars", dexpreoptBootJarsFactory)
 	ctx.RegisterModuleType("art_boot_images", artBootImagesFactory)
 	ctx.FinalDepsMutators(func(ctx android.RegisterMutatorsContext) {
-		ctx.BottomUp("dex_bootjars_deps", DexpreoptBootJarsMutator).Parallel()
+		ctx.BottomUp("dex_bootjars_deps", DexpreoptBootJarsMutator)
 	})
 }
 
diff --git a/java/java.go b/java/java.go
index d97288768..0b48873f6 100644
--- a/java/java.go
+++ b/java/java.go
@@ -70,9 +70,9 @@ func registerJavaBuildComponents(ctx android.RegistrationContext) {
 	// established, to not get the dependencies split into the wrong variants and
 	// to support the checks in dexpreoptDisabled().
 	ctx.FinalDepsMutators(func(ctx android.RegisterMutatorsContext) {
-		ctx.BottomUp("dexpreopt_tool_deps", dexpreoptToolDepsMutator).Parallel()
+		ctx.BottomUp("dexpreopt_tool_deps", dexpreoptToolDepsMutator)
 		// needs access to ApexInfoProvider which is available after variant creation
-		ctx.BottomUp("jacoco_deps", jacocoDepsMutator).Parallel()
+		ctx.BottomUp("jacoco_deps", jacocoDepsMutator)
 	})
 
 	ctx.RegisterParallelSingletonType("kythe_java_extract", kytheExtractJavaFactory)
diff --git a/rust/rust.go b/rust/rust.go
index a044a99dd..b22ebf7e7 100644
--- a/rust/rust.go
+++ b/rust/rust.go
@@ -47,11 +47,11 @@ func init() {
 func registerPreDepsMutators(ctx android.RegisterMutatorsContext) {
 	ctx.Transition("rust_libraries", &libraryTransitionMutator{})
 	ctx.Transition("rust_stdlinkage", &libstdTransitionMutator{})
-	ctx.BottomUp("rust_begin", BeginMutator).Parallel()
+	ctx.BottomUp("rust_begin", BeginMutator)
 }
 
 func registerPostDepsMutators(ctx android.RegisterMutatorsContext) {
-	ctx.BottomUp("rust_sanitizers", rustSanitizerRuntimeMutator).Parallel()
+	ctx.BottomUp("rust_sanitizers", rustSanitizerRuntimeMutator)
 }
 
 type Flags struct {