xref: /aosp_15_r20/build/soong/android/prebuilt.go (revision 333d2b3687b3a337dbcca9d65000bca186795e39)
1// Copyright 2016 Google Inc. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package android
16
17import (
18	"fmt"
19	"reflect"
20	"strings"
21
22	"github.com/google/blueprint"
23	"github.com/google/blueprint/proptools"
24)
25
26// This file implements common functionality for handling modules that may exist as prebuilts,
27// source, or both.
28
29func RegisterPrebuiltMutators(ctx RegistrationContext) {
30	ctx.PreArchMutators(RegisterPrebuiltsPreArchMutators)
31	ctx.PostDepsMutators(RegisterPrebuiltsPostDepsMutators)
32}
33
34// Marks a dependency tag as possibly preventing a reference to a source from being
35// replaced with the prebuilt.
36type ReplaceSourceWithPrebuilt interface {
37	blueprint.DependencyTag
38
39	// Return true if the dependency defined by this tag should be replaced with the
40	// prebuilt.
41	ReplaceSourceWithPrebuilt() bool
42}
43
44type prebuiltDependencyTag struct {
45	blueprint.BaseDependencyTag
46}
47
48var PrebuiltDepTag prebuiltDependencyTag
49
50// Mark this tag so dependencies that use it are excluded from visibility enforcement.
51func (t prebuiltDependencyTag) ExcludeFromVisibilityEnforcement() {}
52
53// Mark this tag so dependencies that use it are excluded from APEX contents.
54func (t prebuiltDependencyTag) ExcludeFromApexContents() {}
55
56var _ ExcludeFromVisibilityEnforcementTag = PrebuiltDepTag
57var _ ExcludeFromApexContentsTag = PrebuiltDepTag
58
59// UserSuppliedPrebuiltProperties contains the prebuilt properties that can be specified in an
60// Android.bp file.
61type UserSuppliedPrebuiltProperties struct {
62	// When prefer is set to true the prebuilt will be used instead of any source module with
63	// a matching name.
64	Prefer proptools.Configurable[bool] `android:"arch_variant,replace_instead_of_append"`
65
66	// When specified this names a Soong config variable that controls the prefer property.
67	//
68	// If the value of the named Soong config variable is true then prefer is set to false and vice
69	// versa. If the Soong config variable is not set then it defaults to false, so prefer defaults
70	// to true.
71	//
72	// If specified then the prefer property is ignored in favor of the value of the Soong config
73	// variable.
74	//
75	// DEPRECATED: This property is being deprecated b/308188211.
76	// Use RELEASE_APEX_CONTRIBUTIONS build flags to select prebuilts of mainline modules.
77	Use_source_config_var *ConfigVarProperties
78}
79
80// CopyUserSuppliedPropertiesFromPrebuilt copies the user supplied prebuilt properties from the
81// prebuilt properties.
82func (u *UserSuppliedPrebuiltProperties) CopyUserSuppliedPropertiesFromPrebuilt(p *Prebuilt) {
83	*u = p.properties.UserSuppliedPrebuiltProperties
84}
85
86type PrebuiltProperties struct {
87	UserSuppliedPrebuiltProperties
88
89	SourceExists bool `blueprint:"mutated"`
90	UsePrebuilt  bool `blueprint:"mutated"`
91
92	// Set if the module has been renamed to remove the "prebuilt_" prefix.
93	PrebuiltRenamedToSource bool `blueprint:"mutated"`
94}
95
96// Properties that can be used to select a Soong config variable.
97type ConfigVarProperties struct {
98	// Allow instances of this struct to be used as a property value in a BpPropertySet.
99	BpPrintableBase
100
101	// The name of the configuration namespace.
102	//
103	// As passed to add_soong_config_namespace in Make.
104	Config_namespace *string
105
106	// The name of the configuration variable.
107	//
108	// As passed to add_soong_config_var_value in Make.
109	Var_name *string
110}
111
112type Prebuilt struct {
113	properties PrebuiltProperties
114
115	// nil if the prebuilt has no srcs property at all. See InitPrebuiltModuleWithoutSrcs.
116	srcsSupplier PrebuiltSrcsSupplier
117
118	// "-" if the prebuilt has no srcs property at all. See InitPrebuiltModuleWithoutSrcs.
119	srcsPropertyName string
120}
121
122// RemoveOptionalPrebuiltPrefix returns the result of removing the "prebuilt_" prefix from the
123// supplied name if it has one, or returns the name unmodified if it does not.
124func RemoveOptionalPrebuiltPrefix(name string) string {
125	return strings.TrimPrefix(name, "prebuilt_")
126}
127
128// RemoveOptionalPrebuiltPrefixFromBazelLabel removes the "prebuilt_" prefix from the *target name* of a Bazel label.
129// This differs from RemoveOptionalPrebuiltPrefix in that it does not remove it from the start of the string, but
130// instead removes it from the target name itself.
131func RemoveOptionalPrebuiltPrefixFromBazelLabel(label string) string {
132	splitLabel := strings.Split(label, ":")
133	bazelModuleNameNoPrebuilt := RemoveOptionalPrebuiltPrefix(splitLabel[1])
134	return strings.Join([]string{
135		splitLabel[0],
136		bazelModuleNameNoPrebuilt,
137	}, ":")
138}
139
140func (p *Prebuilt) Name(name string) string {
141	return PrebuiltNameFromSource(name)
142}
143
144// PrebuiltNameFromSource returns the result of prepending the "prebuilt_" prefix to the supplied
145// name.
146func PrebuiltNameFromSource(name string) string {
147	return "prebuilt_" + name
148}
149
150func (p *Prebuilt) ForcePrefer() {
151	p.properties.Prefer = NewSimpleConfigurable(true)
152}
153
154// SingleSourcePathFromSupplier invokes the supplied supplier for the current module in the
155// supplied context to retrieve a list of file paths, ensures that the returned list of file paths
156// contains a single value and then assumes that is a module relative file path and converts it to
157// a Path accordingly.
158//
159// Any issues, such as nil supplier or not exactly one file path will be reported as errors on the
160// supplied context and this will return nil.
161func SingleSourcePathFromSupplier(ctx ModuleContext, srcsSupplier PrebuiltSrcsSupplier, srcsPropertyName string) Path {
162	if srcsSupplier != nil {
163		srcs := srcsSupplier(ctx, ctx.Module())
164
165		if len(srcs) == 0 {
166			ctx.PropertyErrorf(srcsPropertyName, "missing prebuilt source file")
167			return nil
168		}
169
170		if len(srcs) > 1 {
171			ctx.PropertyErrorf(srcsPropertyName, "multiple prebuilt source files")
172			return nil
173		}
174
175		// Return the singleton source after expanding any filegroup in the
176		// sources.
177		src := srcs[0]
178		return PathForModuleSrc(ctx, src)
179	} else {
180		ctx.ModuleErrorf("prebuilt source was not set")
181		return nil
182	}
183}
184
185// The below source-related functions and the srcs, src fields are based on an assumption that
186// prebuilt modules have a static source property at the moment. Currently there is only one
187// exception, android_app_import, which chooses a source file depending on the product's DPI
188// preference configs. We'll want to add native support for dynamic source cases if we end up having
189// more modules like this.
190func (p *Prebuilt) SingleSourcePath(ctx ModuleContext) Path {
191	return SingleSourcePathFromSupplier(ctx, p.srcsSupplier, p.srcsPropertyName)
192}
193
194func (p *Prebuilt) UsePrebuilt() bool {
195	return p.properties.UsePrebuilt
196}
197
198// Called to provide the srcs value for the prebuilt module.
199//
200// This can be called with a context for any module not just the prebuilt one itself. It can also be
201// called concurrently.
202//
203// Return the src value or nil if it is not available.
204type PrebuiltSrcsSupplier func(ctx BaseModuleContext, prebuilt Module) []string
205
206func initPrebuiltModuleCommon(module PrebuiltInterface) *Prebuilt {
207	p := module.Prebuilt()
208	module.AddProperties(&p.properties)
209	return p
210}
211
212// Initialize the module as a prebuilt module that has no dedicated property that lists its
213// sources. SingleSourcePathFromSupplier should not be called for this module.
214//
215// This is the case e.g. for header modules, which provides the headers in source form
216// regardless whether they are prebuilt or not.
217func InitPrebuiltModuleWithoutSrcs(module PrebuiltInterface) {
218	p := initPrebuiltModuleCommon(module)
219	p.srcsPropertyName = "-"
220}
221
222// Initialize the module as a prebuilt module that uses the provided supplier to access the
223// prebuilt sources of the module.
224//
225// The supplier will be called multiple times and must return the same values each time it
226// is called. If it returns an empty array (or nil) then the prebuilt module will not be used
227// as a replacement for a source module with the same name even if prefer = true.
228//
229// If the Prebuilt.SingleSourcePath() is called on the module then this must return an array
230// containing exactly one source file.
231//
232// The provided property name is used to provide helpful error messages in the event that
233// a problem arises, e.g. calling SingleSourcePath() when more than one source is provided.
234func InitPrebuiltModuleWithSrcSupplier(module PrebuiltInterface, srcsSupplier PrebuiltSrcsSupplier, srcsPropertyName string) {
235	if srcsSupplier == nil {
236		panic(fmt.Errorf("srcsSupplier must not be nil"))
237	}
238	if srcsPropertyName == "" {
239		panic(fmt.Errorf("srcsPropertyName must not be empty"))
240	}
241
242	p := initPrebuiltModuleCommon(module)
243	p.srcsSupplier = srcsSupplier
244	p.srcsPropertyName = srcsPropertyName
245}
246
247// InitPrebuiltModule is the same as InitPrebuiltModuleWithSrcSupplier, but uses the
248// provided list of strings property as the source provider.
249func InitPrebuiltModule(module PrebuiltInterface, srcs *[]string) {
250	if srcs == nil {
251		panic(fmt.Errorf("srcs must not be nil"))
252	}
253
254	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
255		return *srcs
256	}
257
258	InitPrebuiltModuleWithSrcSupplier(module, srcsSupplier, "srcs")
259}
260
261// InitConfigurablePrebuiltModule is the same as InitPrebuiltModule, but uses a
262// Configurable list of strings property instead of a regular list of strings.
263func InitConfigurablePrebuiltModule(module PrebuiltInterface, srcs *proptools.Configurable[[]string]) {
264	if srcs == nil {
265		panic(fmt.Errorf("srcs must not be nil"))
266	}
267
268	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
269		return srcs.GetOrDefault(ctx, nil)
270	}
271
272	InitPrebuiltModuleWithSrcSupplier(module, srcsSupplier, "srcs")
273}
274
275// InitConfigurablePrebuiltModuleString is the same as InitPrebuiltModule, but uses a
276// Configurable string property instead of a regular list of strings. It only produces a single
277// source file.
278func InitConfigurablePrebuiltModuleString(module PrebuiltInterface, srcs *proptools.Configurable[string], propertyName string) {
279	if srcs == nil {
280		panic(fmt.Errorf("%s must not be nil", propertyName))
281	}
282
283	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
284		src := srcs.GetOrDefault(ctx, "")
285		if src == "" {
286			return nil
287		}
288		return []string{src}
289	}
290
291	InitPrebuiltModuleWithSrcSupplier(module, srcsSupplier, propertyName)
292}
293
294func InitSingleSourcePrebuiltModule(module PrebuiltInterface, srcProps interface{}, srcField string) {
295	srcPropsValue := reflect.ValueOf(srcProps).Elem()
296	srcStructField, _ := srcPropsValue.Type().FieldByName(srcField)
297	if !srcPropsValue.IsValid() || srcStructField.Name == "" {
298		panic(fmt.Errorf("invalid single source prebuilt %+v", module))
299	}
300
301	if srcPropsValue.Kind() != reflect.Struct && srcPropsValue.Kind() != reflect.Interface {
302		panic(fmt.Errorf("invalid single source prebuilt %+v", srcProps))
303	}
304
305	srcFieldIndex := srcStructField.Index
306	srcPropertyName := proptools.PropertyNameForField(srcField)
307
308	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
309		if !module.Enabled(ctx) {
310			return nil
311		}
312		value := srcPropsValue.FieldByIndex(srcFieldIndex)
313		if value.Kind() == reflect.Ptr {
314			if value.IsNil() {
315				return nil
316			}
317			value = value.Elem()
318		}
319		if value.Kind() != reflect.String {
320			panic(fmt.Errorf("prebuilt src field %q in %T in module %s should be a string or a pointer to one but was %v", srcField, srcProps, module, value))
321		}
322		src := value.String()
323		if src == "" {
324			return nil
325		}
326		return []string{src}
327	}
328
329	InitPrebuiltModuleWithSrcSupplier(module, srcsSupplier, srcPropertyName)
330}
331
332type PrebuiltInterface interface {
333	Module
334	Prebuilt() *Prebuilt
335}
336
337// IsModulePreferred returns true if the given module is preferred.
338//
339// A source module is preferred if there is no corresponding prebuilt module or the prebuilt module
340// does not have "prefer: true".
341//
342// A prebuilt module is preferred if there is no corresponding source module or the prebuilt module
343// has "prefer: true".
344func IsModulePreferred(module Module) bool {
345	if module.IsReplacedByPrebuilt() {
346		// A source module that has been replaced by a prebuilt counterpart.
347		return false
348	}
349	if p := GetEmbeddedPrebuilt(module); p != nil {
350		return p.UsePrebuilt()
351	}
352	return true
353}
354
355// IsModulePrebuilt returns true if the module implements PrebuiltInterface and
356// has been initialized as a prebuilt and so returns a non-nil value from the
357// PrebuiltInterface.Prebuilt() method.
358func IsModulePrebuilt(module Module) bool {
359	return GetEmbeddedPrebuilt(module) != nil
360}
361
362// GetEmbeddedPrebuilt returns a pointer to the embedded Prebuilt structure or
363// nil if the module does not implement PrebuiltInterface or has not been
364// initialized as a prebuilt module.
365func GetEmbeddedPrebuilt(module Module) *Prebuilt {
366	if p, ok := module.(PrebuiltInterface); ok {
367		return p.Prebuilt()
368	}
369
370	return nil
371}
372
373// PrebuiltGetPreferred returns the module that is preferred for the given
374// module. That is either the module itself or the prebuilt counterpart that has
375// taken its place. The given module must be a direct dependency of the current
376// context module, and it must be the source module if both source and prebuilt
377// exist.
378//
379// This function is for use on dependencies after PrebuiltPostDepsMutator has
380// run - any dependency that is registered before that will already reference
381// the right module. This function is only safe to call after all TransitionMutators
382// have run, e.g. in GenerateAndroidBuildActions.
383func PrebuiltGetPreferred(ctx BaseModuleContext, module Module) Module {
384	if !OtherModuleProviderOrDefault(ctx, module, CommonModuleInfoKey).ReplacedByPrebuilt {
385		return module
386	}
387	if _, ok := OtherModuleProvider(ctx, module, PrebuiltModuleProviderKey); ok {
388		// If we're given a prebuilt then assume there's no source module around.
389		return module
390	}
391
392	sourceModDepFound := false
393	var prebuiltMod Module
394
395	ctx.WalkDepsProxy(func(child, parent ModuleProxy) bool {
396		if prebuiltMod != nil {
397			return false
398		}
399		if ctx.EqualModules(parent, ctx.Module()) {
400			// First level: Only recurse if the module is found as a direct dependency.
401			sourceModDepFound = child == module
402			return sourceModDepFound
403		}
404		// Second level: Follow PrebuiltDepTag to the prebuilt.
405		if t := ctx.OtherModuleDependencyTag(child); t == PrebuiltDepTag {
406			prebuiltMod = child
407		}
408		return false
409	})
410
411	if prebuiltMod == nil {
412		if !sourceModDepFound {
413			panic(fmt.Errorf("Failed to find source module as a direct dependency: %s", module))
414		} else {
415			panic(fmt.Errorf("Failed to find prebuilt for source module: %s", module))
416		}
417	}
418	return prebuiltMod
419}
420
421func RegisterPrebuiltsPreArchMutators(ctx RegisterMutatorsContext) {
422	ctx.BottomUp("prebuilt_rename", PrebuiltRenameMutator).UsesRename()
423}
424
425func RegisterPrebuiltsPostDepsMutators(ctx RegisterMutatorsContext) {
426	ctx.BottomUp("prebuilt_source", PrebuiltSourceDepsMutator).UsesReverseDependencies()
427	ctx.BottomUp("prebuilt_select", PrebuiltSelectModuleMutator)
428	ctx.BottomUp("prebuilt_postdeps", PrebuiltPostDepsMutator).UsesReplaceDependencies()
429}
430
431// Returns the name of the source module corresponding to a prebuilt module
432// For source modules, it returns its own name
433type baseModuleName interface {
434	BaseModuleName() string
435}
436
437// PrebuiltRenameMutator ensures that there always is a module with an
438// undecorated name.
439func PrebuiltRenameMutator(ctx BottomUpMutatorContext) {
440	m := ctx.Module()
441	if p := GetEmbeddedPrebuilt(m); p != nil {
442		bmn, _ := m.(baseModuleName)
443		name := bmn.BaseModuleName()
444		if !ctx.OtherModuleExists(name) {
445			ctx.Rename(name)
446			p.properties.PrebuiltRenamedToSource = true
447		}
448	}
449}
450
451// PrebuiltSourceDepsMutator adds dependencies to the prebuilt module from the
452// corresponding source module, if one exists for the same variant.
453// Add a dependency from the prebuilt to `all_apex_contributions`
454// The metadata will be used for source vs prebuilts selection
455func PrebuiltSourceDepsMutator(ctx BottomUpMutatorContext) {
456	m := ctx.Module()
457	if p := GetEmbeddedPrebuilt(m); p != nil {
458		// Add a dependency from the prebuilt to the `all_apex_contributions`
459		// metadata module
460		// TODO: When all branches contain this singleton module, make this strict
461		// TODO: Add this dependency only for mainline prebuilts and not every prebuilt module
462		if ctx.OtherModuleExists("all_apex_contributions") {
463			ctx.AddDependency(m, AcDepTag, "all_apex_contributions")
464		}
465		if m.Enabled(ctx) && !p.properties.PrebuiltRenamedToSource {
466			// If this module is a prebuilt, is enabled and has not been renamed to source then add a
467			// dependency onto the source if it is present.
468			bmn, _ := m.(baseModuleName)
469			name := bmn.BaseModuleName()
470			if ctx.OtherModuleReverseDependencyVariantExists(name) {
471				ctx.AddReverseDependency(ctx.Module(), PrebuiltDepTag, name)
472				p.properties.SourceExists = true
473			}
474		}
475	}
476}
477
478// checkInvariantsForSourceAndPrebuilt checks if invariants are kept when replacing
479// source with prebuilt. Note that the current module for the context is the source module.
480func checkInvariantsForSourceAndPrebuilt(ctx BaseModuleContext, s, p Module) {
481	if _, ok := s.(OverrideModule); ok {
482		// skip the check when the source module is `override_X` because it's only a placeholder
483		// for the actual source module. The check will be invoked for the actual module.
484		return
485	}
486	if sourcePartition, prebuiltPartition := s.PartitionTag(ctx.DeviceConfig()), p.PartitionTag(ctx.DeviceConfig()); sourcePartition != prebuiltPartition {
487		ctx.OtherModuleErrorf(p, "partition is different: %s(%s) != %s(%s)",
488			sourcePartition, ctx.ModuleName(), prebuiltPartition, ctx.OtherModuleName(p))
489	}
490}
491
492// PrebuiltSelectModuleMutator marks prebuilts that are used, either overriding source modules or
493// because the source module doesn't exist.  It also disables installing overridden source modules.
494//
495// If the visited module is the metadata module `all_apex_contributions`, it sets a
496// provider containing metadata about whether source or prebuilt of mainline modules should be used.
497// This logic was added here to prevent the overhead of creating a new mutator.
498func PrebuiltSelectModuleMutator(ctx BottomUpMutatorContext) {
499	m := ctx.Module()
500	if p := GetEmbeddedPrebuilt(m); p != nil {
501		if p.srcsSupplier == nil && p.srcsPropertyName == "" {
502			panic(fmt.Errorf("prebuilt module did not have InitPrebuiltModule called on it"))
503		}
504		if !p.properties.SourceExists {
505			p.properties.UsePrebuilt = p.usePrebuilt(ctx, nil, m)
506		}
507		// Propagate the provider received from `all_apex_contributions`
508		// to the source module
509		ctx.VisitDirectDepsWithTag(AcDepTag, func(am Module) {
510			psi, _ := OtherModuleProvider(ctx, am, PrebuiltSelectionInfoProvider)
511			SetProvider(ctx, PrebuiltSelectionInfoProvider, psi)
512		})
513
514	} else if s, ok := ctx.Module().(Module); ok {
515		// Use `all_apex_contributions` for source vs prebuilt selection.
516		psi := PrebuiltSelectionInfoMap{}
517		ctx.VisitDirectDepsWithTag(PrebuiltDepTag, func(am Module) {
518			// The value of psi gets overwritten with the provider from the last visited prebuilt.
519			// But all prebuilts have the same value of the provider, so this should be idempontent.
520			psi, _ = OtherModuleProvider(ctx, am, PrebuiltSelectionInfoProvider)
521		})
522		ctx.VisitDirectDepsWithTag(PrebuiltDepTag, func(prebuiltModule Module) {
523			p := GetEmbeddedPrebuilt(prebuiltModule)
524			if p.usePrebuilt(ctx, s, prebuiltModule) {
525				checkInvariantsForSourceAndPrebuilt(ctx, s, prebuiltModule)
526
527				p.properties.UsePrebuilt = true
528				s.ReplacedByPrebuilt()
529			}
530		})
531
532		// If any module in this mainline module family has been flagged using apex_contributions, disable every other module in that family
533		// Add source
534		allModules := []Module{s}
535		// Add each prebuilt
536		ctx.VisitDirectDepsWithTag(PrebuiltDepTag, func(prebuiltModule Module) {
537			allModules = append(allModules, prebuiltModule)
538		})
539		hideUnflaggedModules(ctx, psi, allModules)
540
541	}
542
543	// If this is `all_apex_contributions`, set a provider containing
544	// metadata about source vs prebuilts selection
545	if am, ok := m.(*allApexContributions); ok {
546		am.SetPrebuiltSelectionInfoProvider(ctx)
547	}
548}
549
550// If any module in this mainline module family has been flagged using apex_contributions, disable every other module in that family
551func hideUnflaggedModules(ctx BottomUpMutatorContext, psi PrebuiltSelectionInfoMap, allModulesInFamily []Module) {
552	var selectedModuleInFamily Module
553	// query all_apex_contributions to see if any module in this family has been selected
554	for _, moduleInFamily := range allModulesInFamily {
555		// validate that are no duplicates
556		if isSelected(psi, moduleInFamily) {
557			if selectedModuleInFamily == nil {
558				// Store this so we can validate that there are no duplicates
559				selectedModuleInFamily = moduleInFamily
560			} else {
561				// There are duplicate modules from the same mainline module family
562				ctx.ModuleErrorf("Found duplicate variations of the same module in apex_contributions: %s and %s. Please remove one of these.\n", selectedModuleInFamily.Name(), moduleInFamily.Name())
563			}
564		}
565	}
566
567	// If a module has been selected, hide all other modules
568	if selectedModuleInFamily != nil {
569		for _, moduleInFamily := range allModulesInFamily {
570			if moduleInFamily.Name() != selectedModuleInFamily.Name() {
571				moduleInFamily.HideFromMake()
572				moduleInFamily.SkipInstall()
573				// If this is a prebuilt module, unset properties.UsePrebuilt
574				// properties.UsePrebuilt might evaluate to true via soong config var fallback mechanism
575				// Set it to false explicitly so that the following mutator does not replace rdeps to this unselected prebuilt
576				if p := GetEmbeddedPrebuilt(moduleInFamily); p != nil {
577					p.properties.UsePrebuilt = false
578				}
579			}
580		}
581	}
582	// Do a validation pass to make sure that multiple prebuilts of a specific module are not selected.
583	// This might happen if the prebuilts share the same soong config var namespace.
584	// This should be an error, unless one of the prebuilts has been explicitly declared in apex_contributions
585	var selectedPrebuilt Module
586	for _, moduleInFamily := range allModulesInFamily {
587		// Skip if this module is in a different namespace
588		if !moduleInFamily.ExportedToMake() {
589			continue
590		}
591		// Skip for the top-level java_sdk_library_(_import). This has some special cases that need to be addressed first.
592		// This does not run into non-determinism because PrebuiltPostDepsMutator also has the special case
593		if sdkLibrary, ok := moduleInFamily.(interface{ SdkLibraryName() *string }); ok && sdkLibrary.SdkLibraryName() != nil {
594			continue
595		}
596		if p := GetEmbeddedPrebuilt(moduleInFamily); p != nil && p.properties.UsePrebuilt {
597			if selectedPrebuilt == nil {
598				selectedPrebuilt = moduleInFamily
599			} else {
600				ctx.ModuleErrorf("Multiple prebuilt modules %v and %v have been marked as preferred for this source module. "+
601					"Please add the appropriate prebuilt module to apex_contributions for this release config.", selectedPrebuilt.Name(), moduleInFamily.Name())
602			}
603		}
604	}
605}
606
607// PrebuiltPostDepsMutator replaces dependencies on the source module with dependencies on the
608// prebuilt when both modules exist and the prebuilt should be used.  When the prebuilt should not
609// be used, disable installing it.
610func PrebuiltPostDepsMutator(ctx BottomUpMutatorContext) {
611	m := ctx.Module()
612	if p := GetEmbeddedPrebuilt(m); p != nil {
613		bmn, _ := m.(baseModuleName)
614		name := bmn.BaseModuleName()
615		psi := PrebuiltSelectionInfoMap{}
616		ctx.VisitDirectDepsWithTag(AcDepTag, func(am Module) {
617			psi, _ = OtherModuleProvider(ctx, am, PrebuiltSelectionInfoProvider)
618		})
619
620		if p.properties.UsePrebuilt {
621			if p.properties.SourceExists {
622				ctx.ReplaceDependenciesIf(name, func(from blueprint.Module, tag blueprint.DependencyTag, to blueprint.Module) bool {
623					if sdkLibrary, ok := m.(interface{ SdkLibraryName() *string }); ok && sdkLibrary.SdkLibraryName() != nil {
624						// Do not replace deps to the top-level prebuilt java_sdk_library hook.
625						// This hook has been special-cased in #isSelected to be _always_ active, even in next builds
626						// for dexpreopt and hiddenapi processing.
627						// If we do not special-case this here, rdeps referring to a java_sdk_library in next builds via libs
628						// will get prebuilt stubs
629						// TODO (b/308187268): Remove this after the apexes have been added to apex_contributions
630						if psi.IsSelected(name) {
631							return false
632						}
633					}
634
635					if t, ok := tag.(ReplaceSourceWithPrebuilt); ok {
636						return t.ReplaceSourceWithPrebuilt()
637					}
638					return true
639				})
640			}
641		} else {
642			m.HideFromMake()
643			m.SkipInstall()
644		}
645	}
646}
647
648// A wrapper around PrebuiltSelectionInfoMap.IsSelected with special handling for java_sdk_library
649// java_sdk_library is a macro that creates
650// 1. top-level impl library
651// 2. stub libraries (suffixed with .stubs...)
652//
653// java_sdk_library_import is a macro that creates
654// 1. top-level "impl" library
655// 2. stub libraries (suffixed with .stubs...)
656//
657// the impl of java_sdk_library_import is a "hook" for hiddenapi and dexpreopt processing. It does not have an impl jar, but acts as a shim
658// to provide the jar deapxed from the prebuilt apex
659//
660// isSelected uses `all_apex_contributions` to supersede source vs prebuilts selection of the stub libraries. It does not supersede the
661// selection of the top-level "impl" library so that this hook can work
662//
663// TODO (b/308174306) - Fix this when we need to support multiple prebuilts in main
664func isSelected(psi PrebuiltSelectionInfoMap, m Module) bool {
665	if sdkLibrary, ok := m.(interface{ SdkLibraryName() *string }); ok && sdkLibrary.SdkLibraryName() != nil {
666		sln := proptools.String(sdkLibrary.SdkLibraryName())
667
668		// This is the top-level library
669		// Do not supersede the existing prebuilts vs source selection mechanisms
670		// TODO (b/308187268): Remove this after the apexes have been added to apex_contributions
671		if bmn, ok := m.(baseModuleName); ok && sln == bmn.BaseModuleName() {
672			return false
673		}
674
675		// Stub library created by java_sdk_library_import
676		// java_sdk_library creates several child modules (java_import + prebuilt_stubs_sources) dynamically.
677		// This code block ensures that these child modules are selected if the top-level java_sdk_library_import is listed
678		// in the selected apex_contributions.
679		if javaImport, ok := m.(createdByJavaSdkLibraryName); ok && javaImport.CreatedByJavaSdkLibraryName() != nil {
680			return psi.IsSelected(PrebuiltNameFromSource(proptools.String(javaImport.CreatedByJavaSdkLibraryName())))
681		}
682
683		// Stub library created by java_sdk_library
684		return psi.IsSelected(sln)
685	}
686	return psi.IsSelected(m.Name())
687}
688
689// implemented by child modules of java_sdk_library_import
690type createdByJavaSdkLibraryName interface {
691	CreatedByJavaSdkLibraryName() *string
692}
693
694// Returns true if the prebuilt variant is disabled
695// e.g. for a cc_prebuilt_library_shared, this will return
696// - true for the static variant of the module
697// - false for the shared variant of the module
698//
699// Even though this is a cc_prebuilt_library_shared, we create both the variants today
700// https://source.corp.google.com/h/googleplex-android/platform/build/soong/+/e08e32b45a18a77bc3c3e751f730539b1b374f1b:cc/library.go;l=2113-2116;drc=2c4a9779cd1921d0397a12b3d3521f4c9b30d747;bpv=1;bpt=0
701func (p *Prebuilt) variantIsDisabled(ctx BaseModuleContext, prebuilt Module) bool {
702	return p.srcsSupplier != nil && len(p.srcsSupplier(ctx, prebuilt)) == 0
703}
704
705type apexVariationName interface {
706	ApexVariationName() string
707}
708
709// usePrebuilt returns true if a prebuilt should be used instead of the source module.  The prebuilt
710// will be used if it is marked "prefer" or if the source module is disabled.
711func (p *Prebuilt) usePrebuilt(ctx BaseModuleContext, source Module, prebuilt Module) bool {
712	isMainlinePrebuilt := func(prebuilt Module) bool {
713		apex, ok := prebuilt.(apexVariationName)
714		if !ok {
715			return false
716		}
717		// Prebuilts of aosp apexes in prebuilts/runtime
718		// Used in minimal art branches
719		if prebuilt.base().BaseModuleName() == apex.ApexVariationName() {
720			return false
721		}
722		return InList(apex.ApexVariationName(), ctx.Config().AllMainlineApexNames())
723	}
724
725	// Use `all_apex_contributions` for source vs prebuilt selection.
726	psi := PrebuiltSelectionInfoMap{}
727	var psiDepTag blueprint.DependencyTag
728	if p := GetEmbeddedPrebuilt(ctx.Module()); p != nil {
729		// This is a prebuilt module, visit all_apex_contributions to get the info
730		psiDepTag = AcDepTag
731	} else {
732		// This is a source module, visit any of its prebuilts to get the info
733		psiDepTag = PrebuiltDepTag
734	}
735	ctx.VisitDirectDepsWithTag(psiDepTag, func(am Module) {
736		psi, _ = OtherModuleProvider(ctx, am, PrebuiltSelectionInfoProvider)
737	})
738
739	// If the source module is explicitly listed in the metadata module, use that
740	if source != nil && isSelected(psi, source) {
741		return false
742	}
743	// If the prebuilt module is explicitly listed in the metadata module, use that
744	if isSelected(psi, prebuilt) && !p.variantIsDisabled(ctx, prebuilt) {
745		return true
746	}
747
748	// If this is a mainline prebuilt, but has not been flagged, hide it.
749	if isMainlinePrebuilt(prebuilt) {
750		return false
751	}
752
753	// If the baseModuleName could not be found in the metadata module,
754	// fall back to the existing source vs prebuilt selection.
755	// TODO: Drop the fallback mechanisms
756
757	if p.variantIsDisabled(ctx, prebuilt) {
758		return false
759	}
760
761	// Skip prebuilt modules under unexported namespaces so that we won't
762	// end up shadowing non-prebuilt module when prebuilt module under same
763	// name happens to have a `Prefer` property set to true.
764	if ctx.Config().KatiEnabled() && !prebuilt.ExportedToMake() {
765		return false
766	}
767
768	// If source is not available or is disabled then always use the prebuilt.
769	if source == nil || !source.Enabled(ctx) {
770		return true
771	}
772
773	// TODO: use p.Properties.Name and ctx.ModuleDir to override preference
774	return p.properties.Prefer.GetOrDefault(ctx, false)
775}
776
777func (p *Prebuilt) SourceExists() bool {
778	return p.properties.SourceExists
779}
780