Some clarifications in preparation to automatically order linker dependencies

Test: Browse the code and determine whether it's easier to understand
Bug: 66260943
Change-Id: I88c24a8a31ef68f428919087d206433659265684

19 files changed, 214 insertions, 206 deletions

diff --git a/android/module.go b/android/module.go
index 9d7f9420..9afc8a7c 100644
--- a/android/module.go
+++ b/android/module.go
@@ -61,7 +61,7 @@ type androidBaseContext interface {
 	Windows() bool
 	Debug() bool
 	PrimaryArch() bool
-	Vendor() bool
+	InstallOnVendorPartition() bool
 	AConfig() Config
 	DeviceConfig() DeviceConfig
 }
@@ -99,7 +99,11 @@ type ModuleContext interface {
 type Module interface {
 	blueprint.Module
 
+	// GenerateAndroidBuildActions is analogous to Blueprints' GenerateBuildActions,
+	// but GenerateAndroidBuildActions also has access to Android-specific information.
+	// For more information, see Module.GenerateBuildActions within Blueprint's module_ctx.go
 	GenerateAndroidBuildActions(ModuleContext)
+
 	DepsMutator(BottomUpMutatorContext)
 
 	base() *ModuleBase
@@ -690,7 +694,7 @@ func (a *androidBaseContextImpl) DeviceConfig() DeviceConfig {
 	return DeviceConfig{a.config.deviceConfig}
 }
 
-func (a *androidBaseContextImpl) Vendor() bool {
+func (a *androidBaseContextImpl) InstallOnVendorPartition() bool {
 	return a.vendor
 }
 
diff --git a/android/mutator.go b/android/mutator.go
index 04407eb3..66a1bad1 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -18,12 +18,13 @@ import (
 	"github.com/google/blueprint"
 )
 
-// Mutator phases:
-//   Pre-arch
-//   Arch
-//   Pre-deps
-//   Deps
-//   PostDeps
+// Phases:
+//   run Pre-arch mutators
+//   run archMutator
+//   run Pre-deps mutators
+//   run depsMutator
+//   run PostDeps mutators
+//   continue on to GenerateAndroidBuildActions
 
 func registerMutatorsToContext(ctx *blueprint.Context, mutators []*mutator) {
 	for _, t := range mutators {
diff --git a/android/paths.go b/android/paths.go
index 09f760a5..f88d650f 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -739,7 +739,7 @@ func PathForModuleInstall(ctx ModuleInstallPathContext, pathComponents ...string
 		var partition string
 		if ctx.InstallInData() {
 			partition = "data"
-		} else if ctx.Vendor() {
+		} else if ctx.InstallOnVendorPartition() {
 			partition = ctx.DeviceConfig().VendorPath()
 		} else {
 			partition = "system"
diff --git a/cc/androidmk.go b/cc/androidmk.go
index 2114031f..194faaba 100644
--- a/cc/androidmk.go
+++ b/cc/androidmk.go
@@ -30,7 +30,7 @@ var (
 type AndroidMkContext interface {
 	Target() android.Target
 	subAndroidMk(*android.AndroidMkData, interface{})
-	vndk() bool
+	useVndk() bool
 }
 
 type subAndroidMkProvider interface {
@@ -64,14 +64,14 @@ func (c *Module) AndroidMk() android.AndroidMkData {
 				if len(c.Properties.AndroidMkSharedLibs) > 0 {
 					fmt.Fprintln(w, "LOCAL_SHARED_LIBRARIES := "+strings.Join(c.Properties.AndroidMkSharedLibs, " "))
 				}
-				if c.Target().Os == android.Android && c.Properties.Sdk_version != "" && !c.vndk() {
+				if c.Target().Os == android.Android && c.Properties.Sdk_version != "" && !c.useVndk() {
 					fmt.Fprintln(w, "LOCAL_SDK_VERSION := "+c.Properties.Sdk_version)
 					fmt.Fprintln(w, "LOCAL_NDK_STL_VARIANT := none")
 				} else {
 					// These are already included in LOCAL_SHARED_LIBRARIES
 					fmt.Fprintln(w, "LOCAL_CXX_STL := none")
 				}
-				if c.vndk() {
+				if c.useVndk() {
 					fmt.Fprintln(w, "LOCAL_USE_VNDK := true")
 				}
 			},
@@ -89,7 +89,7 @@ func (c *Module) AndroidMk() android.AndroidMkData {
 	}
 	c.subAndroidMk(&ret, c.installer)
 
-	if c.vndk() && c.hasVendorVariant() {
+	if c.useVndk() && c.hasVendorVariant() {
 		// .vendor suffix is added only when we will have two variants: core and vendor.
 		// The suffix is not added for vendor-only module.
 		ret.SubName += vendorSuffix
@@ -161,7 +161,7 @@ func (library *libraryDecorator) AndroidMk(ctx AndroidMkContext, ret *android.An
 				}
 				fmt.Fprintln(w, "LOCAL_MODULE_HOST_OS :=", makeOs)
 				fmt.Fprintln(w, "LOCAL_IS_HOST_MODULE := true")
-			} else if ctx.vndk() {
+			} else if ctx.useVndk() {
 				fmt.Fprintln(w, "LOCAL_USE_VNDK := true")
 			}
 
diff --git a/cc/binary.go b/cc/binary.go
index b2405b6f..30e017f4 100644
--- a/cc/binary.go
+++ b/cc/binary.go
@@ -108,7 +108,7 @@ func (binary *binaryDecorator) linkerDeps(ctx DepsContext, deps Deps) Deps {
 	deps = binary.baseLinker.linkerDeps(ctx, deps)
 	if ctx.toolchain().Bionic() {
 		if !Bool(binary.baseLinker.Properties.Nocrt) {
-			if !ctx.sdk() {
+			if !ctx.useSdk() {
 				if binary.static() {
 					deps.CrtBegin = "crtbegin_static"
 				} else {
diff --git a/cc/builder.go b/cc/builder.go
index b5bdc3d3..742f7fbf 100644
--- a/cc/builder.go
+++ b/cc/builder.go
@@ -219,7 +219,7 @@ type builderFlags struct {
 	arFlags       string
 	asFlags       string
 	cFlags        string
-	toolingCFlags string // Seperate set of Cflags for clang LibTooling tools
+	toolingCFlags string // A separate set of Cflags for clang LibTooling tools
 	conlyFlags    string
 	cppFlags      string
 	ldFlags       string
@@ -584,7 +584,7 @@ func transformDarwinObjToStaticLib(ctx android.ModuleContext, objFiles android.P
 }
 
 // Generate a rule for compiling multiple .o files, plus static libraries, whole static libraries,
-// and shared libraires, to a shared library (.so) or dynamic executable
+// and shared libraries, to a shared library (.so) or dynamic executable
 func TransformObjToDynamicBinary(ctx android.ModuleContext,
 	objFiles, sharedLibs, staticLibs, lateStaticLibs, wholeStaticLibs, deps android.Paths,
 	crtBegin, crtEnd android.OptionalPath, groupLate bool, flags builderFlags, outputFile android.WritablePath) {
@@ -714,8 +714,8 @@ func SourceAbiDiff(ctx android.ModuleContext, inputDump android.Path, referenceD
 	return android.OptionalPathForPath(outputFile)
 }
 
-// Generate a rule for extract a table of contents from a shared library (.so)
-func TransformSharedObjectToToc(ctx android.ModuleContext, inputFile android.WritablePath,
+// Generate a rule for extracting a table of contents from a shared library (.so)
+func TransformSharedObjectToToc(ctx android.ModuleContext, inputFile android.Path,
 	outputFile android.WritablePath, flags builderFlags) {
 
 	crossCompile := gccCmd(flags.toolchain, "")
diff --git a/cc/cc.go b/cc/cc.go
index 4c02e9e2..2fafaa29 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -197,9 +197,9 @@ type ModuleContextIntf interface {
 	clang() bool
 	toolchain() config.Toolchain
 	noDefaultCompilerFlags() bool
-	sdk() bool
+	useSdk() bool
 	sdkVersion() string
-	vndk() bool
+	useVndk() bool
 	isVndk() bool
 	isVndkSp() bool
 	createVndkSourceAbiDump() bool
@@ -382,7 +382,7 @@ func (c *Module) isDependencyRoot() bool {
 	return false
 }
 
-func (c *Module) vndk() bool {
+func (c *Module) useVndk() bool {
 	return c.Properties.UseVndk
 }
 
@@ -414,10 +414,8 @@ type moduleContext struct {
 	moduleContextImpl
 }
 
-// Vendor returns true for vendor modules excluding VNDK libraries so that
-// they get installed onto the correct partition
-func (ctx *moduleContext) Vendor() bool {
-	return ctx.ModuleContext.Vendor() || (ctx.mod.vndk() && !ctx.mod.isVndk())
+func (ctx *moduleContext) InstallOnVendorPartition() bool {
+	return ctx.ModuleContext.InstallOnVendorPartition() || (ctx.mod.useVndk() && !ctx.mod.isVndk())
 }
 
 type moduleContextImpl struct {
@@ -455,8 +453,8 @@ func (ctx *moduleContextImpl) noDefaultCompilerFlags() bool {
 	return Bool(ctx.mod.Properties.No_default_compiler_flags)
 }
 
-func (ctx *moduleContextImpl) sdk() bool {
-	if ctx.ctx.Device() && !ctx.vndk() {
+func (ctx *moduleContextImpl) useSdk() bool {
+	if ctx.ctx.Device() && !ctx.useVndk() {
 		return ctx.mod.Properties.Sdk_version != ""
 	}
 	return false
@@ -464,7 +462,7 @@ func (ctx *moduleContextImpl) sdk() bool {
 
 func (ctx *moduleContextImpl) sdkVersion() string {
 	if ctx.ctx.Device() {
-		if ctx.vndk() {
+		if ctx.useVndk() {
 			return "current"
 		} else {
 			return ctx.mod.Properties.Sdk_version
@@ -473,13 +471,12 @@ func (ctx *moduleContextImpl) sdkVersion() string {
 	return ""
 }
 
-func (ctx *moduleContextImpl) vndk() bool {
-	return ctx.mod.vndk()
-}
-
 func (ctx *moduleContextImpl) isVndk() bool {
 	return ctx.mod.isVndk()
 }
+func (ctx *moduleContextImpl) useVndk() bool {
+	return ctx.mod.useVndk()
+}
 
 func (ctx *moduleContextImpl) isVndkSp() bool {
 	if vndk := ctx.mod.vndkdep; vndk != nil {
@@ -490,7 +487,7 @@ func (ctx *moduleContextImpl) isVndkSp() bool {
 
 // Create source abi dumps if the module belongs to the list of VndkLibraries.
 func (ctx *moduleContextImpl) createVndkSourceAbiDump() bool {
-	return ctx.ctx.Device() && ((ctx.vndk() && ctx.isVndk()) || inList(ctx.baseModuleName(), llndkLibraries))
+	return ctx.ctx.Device() && ((ctx.useVndk() && ctx.isVndk()) || inList(ctx.baseModuleName(), llndkLibraries))
 }
 
 func (ctx *moduleContextImpl) selectedStl() string {
@@ -544,6 +541,7 @@ func (c *Module) Name() string {
 }
 
 func (c *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
+
 	ctx := &moduleContext{
 		ModuleContext: actx,
 		moduleContextImpl: moduleContextImpl{
@@ -669,7 +667,7 @@ func (c *Module) begin(ctx BaseModuleContext) {
 	for _, feature := range c.features {
 		feature.begin(ctx)
 	}
-	if ctx.sdk() {
+	if ctx.useSdk() {
 		version, err := normalizeNdkApiLevel(ctx, ctx.sdkVersion(), ctx.Arch())
 		if err != nil {
 			ctx.PropertyErrorf("sdk_version", err.Error())
@@ -781,27 +779,31 @@ func (c *Module) DepsMutator(actx android.BottomUpMutatorContext) {
 	if ctx.Os() == android.Android {
 		version := ctx.sdkVersion()
 
-		// Rewrites the names of shared libraries into the names of the NDK
-		// libraries where appropriate. This returns two slices.
+		// rewriteNdkLibs takes a list of names of shared libraries and scans it for three types
+		// of names:
 		//
-		// The first is a list of non-variant shared libraries (either rewritten
-		// NDK libraries to the modules in prebuilts/ndk, or not rewritten
-		// because they are not NDK libraries).
+		// 1. Name of an NDK library that refers to a prebuilt module.
+		//    For each of these, it adds the name of the prebuilt module (which will be in
+		//    prebuilts/ndk) to the list of nonvariant libs.
+		// 2. Name of an NDK library that refers to an ndk_library module.
+		//    For each of these, it adds the name of the ndk_library module to the list of
+		//    variant libs.
+		// 3. Anything else (so anything that isn't an NDK library).
+		//    It adds these to the nonvariantLibs list.
 		//
-		// The second is a list of ndk_library modules. These need to be
-		// separated because they are a variation dependency and must be added
-		// in a different manner.
-		rewriteNdkLibs := func(list []string) ([]string, []string) {
-			variantLibs := []string{}
-			nonvariantLibs := []string{}
+		// The caller can then know to add the variantLibs dependencies differently from the
+		// nonvariantLibs
+		rewriteNdkLibs := func(list []string) (nonvariantLibs []string, variantLibs []string) {
+			variantLibs = []string{}
+			nonvariantLibs = []string{}
 			for _, entry := range list {
-				if ctx.sdk() && inList(entry, ndkPrebuiltSharedLibraries) {
+				if ctx.useSdk() && inList(entry, ndkPrebuiltSharedLibraries) {
 					if !inList(entry, ndkMigratedLibs) {
 						nonvariantLibs = append(nonvariantLibs, entry+".ndk."+version)
 					} else {
 						variantLibs = append(variantLibs, entry+ndkLibrarySuffix)
 					}
-				} else if ctx.vndk() && inList(entry, llndkLibraries) {
+				} else if ctx.useVndk() && inList(entry, llndkLibraries) {
 					nonvariantLibs = append(nonvariantLibs, entry+llndkLibrarySuffix)
 				} else {
 					nonvariantLibs = append(nonvariantLibs, entry)
@@ -903,117 +905,118 @@ func (c *Module) clang(ctx BaseModuleContext) bool {
 	return clang
 }
 
-// Convert dependencies to paths.  Returns a PathDeps containing paths
-func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
-	var depPaths PathDeps
-
-	// Whether a module can link to another module, taking into
-	// account NDK linking.
-	checkLinkType := func(from, to *Module) {
-		if from.Target().Os != android.Android {
-			// Host code is not restricted
-			return
-		}
-		if from.Properties.UseVndk {
-			// Though vendor code is limited by the vendor mutator,
-			// each vendor-available module needs to check
-			// link-type for VNDK.
-			if from.vndkdep != nil {
-				from.vndkdep.vndkCheckLinkType(ctx, to)
-			}
-			return
-		}
-		if from.Properties.Sdk_version == "" {
-			// Platform code can link to anything
-			return
-		}
-		if _, ok := to.linker.(*toolchainLibraryDecorator); ok {
-			// These are always allowed
-			return
-		}
-		if _, ok := to.linker.(*ndkPrebuiltLibraryLinker); ok {
-			// These are allowed, but don't set sdk_version
-			return
-		}
-		if _, ok := to.linker.(*ndkPrebuiltStlLinker); ok {
-			// These are allowed, but don't set sdk_version
-			return
-		}
-		if _, ok := to.linker.(*stubDecorator); ok {
-			// These aren't real libraries, but are the stub shared libraries that are included in
-			// the NDK.
-			return
-		}
-		if to.Properties.Sdk_version == "" {
-			// NDK code linking to platform code is never okay.
-			ctx.ModuleErrorf("depends on non-NDK-built library %q",
-				ctx.OtherModuleName(to))
+// Whether a module can link to another module, taking into
+// account NDK linking.
+func checkLinkType(ctx android.ModuleContext, from *Module, to *Module) {
+	if from.Target().Os != android.Android {
+		// Host code is not restricted
+		return
+	}
+	if from.Properties.UseVndk {
+		// Though vendor code is limited by the vendor mutator,
+		// each vendor-available module needs to check
+		// link-type for VNDK.
+		if from.vndkdep != nil {
+			from.vndkdep.vndkCheckLinkType(ctx, to)
 		}
+		return
+	}
+	if from.Properties.Sdk_version == "" {
+		// Platform code can link to anything
+		return
+	}
+	if _, ok := to.linker.(*toolchainLibraryDecorator); ok {
+		// These are always allowed
+		return
+	}
+	if _, ok := to.linker.(*ndkPrebuiltLibraryLinker); ok {
+		// These are allowed, but they don't set sdk_version
+		return
+	}
+	if _, ok := to.linker.(*ndkPrebuiltStlLinker); ok {
+		// These are allowed, but they don't set sdk_version
+		return
+	}
+	if _, ok := to.linker.(*stubDecorator); ok {
+		// These aren't real libraries, but are the stub shared libraries that are included in
+		// the NDK.
+		return
+	}
+	if to.Properties.Sdk_version == "" {
+		// NDK code linking to platform code is never okay.
+		ctx.ModuleErrorf("depends on non-NDK-built library %q",
+			ctx.OtherModuleName(to))
+	}
 
-		// All this point we know we have two NDK libraries, but we need to
-		// check that we're not linking against anything built against a higher
-		// API level, as it is only valid to link against older or equivalent
-		// APIs.
+	// At this point we know we have two NDK libraries, but we need to
+	// check that we're not linking against anything built against a higher
+	// API level, as it is only valid to link against older or equivalent
+	// APIs.
 
-		if from.Properties.Sdk_version == "current" {
-			// Current can link against anything.
-			return
-		} else if to.Properties.Sdk_version == "current" {
-			// Current can't be linked against by anything else.
-			ctx.ModuleErrorf("links %q built against newer API version %q",
-				ctx.OtherModuleName(to), "current")
-		}
+	if from.Properties.Sdk_version == "current" {
+		// Current can link against anything.
+		return
+	} else if to.Properties.Sdk_version == "current" {
+		// Current can't be linked against by anything else.
+		ctx.ModuleErrorf("links %q built against newer API version %q",
+			ctx.OtherModuleName(to), "current")
+	}
 
-		fromApi, err := strconv.Atoi(from.Properties.Sdk_version)
-		if err != nil {
-			ctx.PropertyErrorf("sdk_version",
-				"Invalid sdk_version value (must be int): %q",
-				from.Properties.Sdk_version)
-		}
-		toApi, err := strconv.Atoi(to.Properties.Sdk_version)
-		if err != nil {
-			ctx.PropertyErrorf("sdk_version",
-				"Invalid sdk_version value (must be int): %q",
-				to.Properties.Sdk_version)
-		}
+	fromApi, err := strconv.Atoi(from.Properties.Sdk_version)
+	if err != nil {
+		ctx.PropertyErrorf("sdk_version",
+			"Invalid sdk_version value (must be int): %q",
+			from.Properties.Sdk_version)
+	}
+	toApi, err := strconv.Atoi(to.Properties.Sdk_version)
+	if err != nil {
+		ctx.PropertyErrorf("sdk_version",
+			"Invalid sdk_version value (must be int): %q",
+			to.Properties.Sdk_version)
+	}
 
-		if toApi > fromApi {
-			ctx.ModuleErrorf("links %q built against newer API version %q",
-				ctx.OtherModuleName(to), to.Properties.Sdk_version)
-		}
+	if toApi > fromApi {
+		ctx.ModuleErrorf("links %q built against newer API version %q",
+			ctx.OtherModuleName(to), to.Properties.Sdk_version)
 	}
+}
 
-	ctx.VisitDirectDeps(func(m blueprint.Module) {
-		name := ctx.OtherModuleName(m)
-		tag := ctx.OtherModuleDependencyTag(m)
+// Convert dependencies to paths.  Returns a PathDeps containing paths
+func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
+	var depPaths PathDeps
 
-		a, _ := m.(android.Module)
-		if a == nil {
-			ctx.ModuleErrorf("module %q not an android module", name)
+	ctx.VisitDirectDeps(func(dep blueprint.Module) {
+		depName := ctx.OtherModuleName(dep)
+		depTag := ctx.OtherModuleDependencyTag(dep)
+
+		aDep, _ := dep.(android.Module)
+		if aDep == nil {
+			ctx.ModuleErrorf("module %q not an android module", depName)
 			return
 		}
 
-		cc, _ := m.(*Module)
-		if cc == nil {
-			switch tag {
+		ccDep, _ := dep.(*Module)
+		if ccDep == nil {
+			// handling for a few module types that aren't cc Module but that are also supported
+			switch depTag {
 			case android.DefaultsDepTag, android.SourceDepTag:
 				// Nothing to do
 			case genSourceDepTag:
-				if genRule, ok := m.(genrule.SourceFileGenerator); ok {
+				if genRule, ok := dep.(genrule.SourceFileGenerator); ok {
 					depPaths.GeneratedSources = append(depPaths.GeneratedSources,
 						genRule.GeneratedSourceFiles()...)
 				} else {
-					ctx.ModuleErrorf("module %q is not a gensrcs or genrule", name)
+					ctx.ModuleErrorf("module %q is not a gensrcs or genrule", depName)
 				}
 				// Support exported headers from a generated_sources dependency
 				fallthrough
 			case genHeaderDepTag, genHeaderExportDepTag:
-				if genRule, ok := m.(genrule.SourceFileGenerator); ok {
+				if genRule, ok := dep.(genrule.SourceFileGenerator); ok {
 					depPaths.GeneratedHeaders = append(depPaths.GeneratedHeaders,
 						genRule.GeneratedSourceFiles()...)
 					flags := includeDirsToFlags(genRule.GeneratedHeaderDirs())
 					depPaths.Flags = append(depPaths.Flags, flags)
-					if tag == genHeaderExportDepTag {
+					if depTag == genHeaderExportDepTag {
 						depPaths.ReexportedFlags = append(depPaths.ReexportedFlags, flags)
 						depPaths.ReexportedFlagsDeps = append(depPaths.ReexportedFlagsDeps,
 							genRule.GeneratedSourceFiles()...)
@@ -1022,46 +1025,46 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 
 					}
 				} else {
-					ctx.ModuleErrorf("module %q is not a genrule", name)
+					ctx.ModuleErrorf("module %q is not a genrule", depName)
 				}
 			case linkerScriptDepTag:
-				if genRule, ok := m.(genrule.SourceFileGenerator); ok {
+				if genRule, ok := dep.(genrule.SourceFileGenerator); ok {
 					files := genRule.GeneratedSourceFiles()
 					if len(files) == 1 {
 						depPaths.LinkerScript = android.OptionalPathForPath(files[0])
 					} else if len(files) > 1 {
-						ctx.ModuleErrorf("module %q can only generate a single file if used for a linker script", name)
+						ctx.ModuleErrorf("module %q can only generate a single file if used for a linker script", depName)
 					}
 				} else {
-					ctx.ModuleErrorf("module %q is not a genrule", name)
+					ctx.ModuleErrorf("module %q is not a genrule", depName)
 				}
 			default:
-				ctx.ModuleErrorf("depends on non-cc module %q", name)
+				ctx.ModuleErrorf("depends on non-cc module %q", depName)
 			}
 			return
 		}
 
-		if !a.Enabled() {
+		// some validation
+		if !aDep.Enabled() {
 			if ctx.AConfig().AllowMissingDependencies() {
-				ctx.AddMissingDependencies([]string{name})
+				ctx.AddMissingDependencies([]string{depName})
 			} else {
-				ctx.ModuleErrorf("depends on disabled module %q", name)
+				ctx.ModuleErrorf("depends on disabled module %q", depName)
 			}
 			return
 		}
-
-		if a.Target().Os != ctx.Os() {
-			ctx.ModuleErrorf("OS mismatch between %q and %q", ctx.ModuleName(), name)
+		if aDep.Target().Os != ctx.Os() {
+			ctx.ModuleErrorf("OS mismatch between %q and %q", ctx.ModuleName(), depName)
 			return
 		}
-
-		if a.Target().Arch.ArchType != ctx.Arch().ArchType {
-			ctx.ModuleErrorf("Arch mismatch between %q and %q", ctx.ModuleName(), name)
+		if aDep.Target().Arch.ArchType != ctx.Arch().ArchType {
+			ctx.ModuleErrorf("Arch mismatch between %q and %q", ctx.ModuleName(), depName)
 			return
 		}
 
-		if tag == reuseObjTag {
-			if l, ok := cc.compiler.(libraryInterface); ok {
+		// re-exporting flags
+		if depTag == reuseObjTag {
+			if l, ok := ccDep.compiler.(libraryInterface); ok {
 				objs, flags, deps := l.reuseObjs()
 				depPaths.Objs = depPaths.Objs.Append(objs)
 				depPaths.ReexportedFlags = append(depPaths.ReexportedFlags, flags...)
@@ -1069,9 +1072,8 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 				return
 			}
 		}
-
-		if t, ok := tag.(dependencyTag); ok && t.library {
-			if i, ok := cc.linker.(exportedFlagsProducer); ok {
+		if t, ok := depTag.(dependencyTag); ok && t.library {
+			if i, ok := ccDep.linker.(exportedFlagsProducer); ok {
 				flags := i.exportedFlags()
 				deps := i.exportedFlagsDeps()
 				depPaths.Flags = append(depPaths.Flags, flags...)
@@ -1087,38 +1089,38 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 				}
 			}
 
-			checkLinkType(c, cc)
+			checkLinkType(ctx, c, ccDep)
 		}
 
 		var ptr *android.Paths
 		var depPtr *android.Paths
 
-		linkFile := cc.outputFile
+		linkFile := ccDep.outputFile
 		depFile := android.OptionalPath{}
 
-		switch tag {
+		switch depTag {
 		case ndkStubDepTag, sharedDepTag, sharedExportDepTag:
 			ptr = &depPaths.SharedLibs
 			depPtr = &depPaths.SharedLibsDeps
-			depFile = cc.linker.(libraryInterface).toc()
+			depFile = ccDep.linker.(libraryInterface).toc()
 		case lateSharedDepTag, ndkLateStubDepTag:
 			ptr = &depPaths.LateSharedLibs
 			depPtr = &depPaths.LateSharedLibsDeps
-			depFile = cc.linker.(libraryInterface).toc()
+			depFile = ccDep.linker.(libraryInterface).toc()
 		case staticDepTag, staticExportDepTag:
 			ptr = &depPaths.StaticLibs
 		case lateStaticDepTag:
 			ptr = &depPaths.LateStaticLibs
 		case wholeStaticDepTag:
 			ptr = &depPaths.WholeStaticLibs
-			staticLib, ok := cc.linker.(libraryInterface)
+			staticLib, ok := ccDep.linker.(libraryInterface)
 			if !ok || !staticLib.static() {
-				ctx.ModuleErrorf("module %q not a static library", name)
+				ctx.ModuleErrorf("module %q not a static library", depName)
 				return
 			}
 
 			if missingDeps := staticLib.getWholeStaticMissingDeps(); missingDeps != nil {
-				postfix := " (required by " + ctx.OtherModuleName(m) + ")"
+				postfix := " (required by " + ctx.OtherModuleName(dep) + ")"
 				for i := range missingDeps {
 					missingDeps[i] += postfix
 				}
@@ -1135,11 +1137,11 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 			depPaths.CrtEnd = linkFile
 		}
 
-		switch tag {
+		switch depTag {
 		case staticDepTag, staticExportDepTag, lateStaticDepTag:
-			staticLib, ok := cc.linker.(libraryInterface)
+			staticLib, ok := ccDep.linker.(libraryInterface)
 			if !ok || !staticLib.static() {
-				ctx.ModuleErrorf("module %q not a static library", name)
+				ctx.ModuleErrorf("module %q not a static library", depName)
 				return
 			}
 
@@ -1150,11 +1152,12 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 				staticLib.objs().coverageFiles...)
 			depPaths.StaticLibObjs.sAbiDumpFiles = append(depPaths.StaticLibObjs.sAbiDumpFiles,
 				staticLib.objs().sAbiDumpFiles...)
+
 		}
 
 		if ptr != nil {
 			if !linkFile.Valid() {
-				ctx.ModuleErrorf("module %q missing output file", name)
+				ctx.ModuleErrorf("module %q missing output file", depName)
 				return
 			}
 			*ptr = append(*ptr, linkFile.Path())
@@ -1168,24 +1171,24 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 			*depPtr = append(*depPtr, dep.Path())
 		}
 
-		// Export the shared libs to the make world. In doing so, .vendor suffix
-		// is added if the lib has both core and vendor variants and this module
-		// is building against vndk. This is because the vendor variant will
-		// have .vendor suffix in its name in the make world. However, if the
-		// lib is a vendor-only lib or this lib is not building against vndk,
-		// then the suffix is not added.
-		switch tag {
+		// Export the shared libs to Make.
+		switch depTag {
 		case sharedDepTag, sharedExportDepTag, lateSharedDepTag:
-			libName := strings.TrimSuffix(name, llndkLibrarySuffix)
+			libName := strings.TrimSuffix(depName, llndkLibrarySuffix)
 			libName = strings.TrimPrefix(libName, "prebuilt_")
 			isLLndk := inList(libName, llndkLibraries)
-			if c.vndk() && (cc.hasVendorVariant() || isLLndk) {
-				libName += vendorSuffix
+			var makeLibName string
+			bothVendorAndCoreVariantsExist := ccDep.hasVendorVariant() || isLLndk
+			if c.useVndk() && bothVendorAndCoreVariantsExist {
+				// The vendor module in Make will have been renamed to not conflict with the core
+				// module, so update the dependency name here accordingly.
+				makeLibName = libName + vendorSuffix
+			} else {
+				makeLibName = libName
 			}
 			// Note: the order of libs in this list is not important because
-			// they merely serve as dependencies in the make world and do not
-			// affect this lib itself.
-			c.Properties.AndroidMkSharedLibs = append(c.Properties.AndroidMkSharedLibs, libName)
+			// they merely serve as Make dependencies and do not affect this lib itself.
+			c.Properties.AndroidMkSharedLibs = append(c.Properties.AndroidMkSharedLibs, makeLibName)
 		}
 	})
 
@@ -1318,7 +1321,7 @@ func vendorMutator(mctx android.BottomUpMutatorContext) {
 				mctx.CreateVariations(coreMode)
 			} else if Bool(props.Vendor_available) {
 				mctx.CreateVariations(coreMode, vendorMode)
-			} else if mctx.Vendor() {
+			} else if mctx.InstallOnVendorPartition() {
 				mctx.CreateVariations(vendorMode)
 			} else {
 				mctx.CreateVariations(coreMode)
@@ -1332,7 +1335,7 @@ func vendorMutator(mctx android.BottomUpMutatorContext) {
 	}
 
 	// Sanity check
-	if m.VendorProperties.Vendor_available != nil && mctx.Vendor() {
+	if m.VendorProperties.Vendor_available != nil && mctx.InstallOnVendorPartition() {
 		mctx.PropertyErrorf("vendor_available",
 			"doesn't make sense at the same time as `vendor: true` or `proprietary: true`")
 		return
@@ -1365,7 +1368,7 @@ func vendorMutator(mctx android.BottomUpMutatorContext) {
 		vendor := mod[1].(*Module)
 		vendor.Properties.UseVndk = true
 		squashVendorSrcs(vendor)
-	} else if mctx.Vendor() && m.Properties.Sdk_version == "" {
+	} else if mctx.InstallOnVendorPartition() && m.Properties.Sdk_version == "" {
 		// This will be available in /vendor only
 		mod := mctx.CreateVariations(vendorMode)
 		vendor := mod[0].(*Module)
@@ -1396,8 +1399,8 @@ outer:
 	return list[:k]
 }
 
-// lastUniqueElements returns all unique elements of a slice, keeping the last copy of each
-// modifies the slice contents in place, and returns a subslice of the original slice
+// lastUniqueElements returns all unique elements of a slice, keeping the last copy of each.
+// It modifies the slice contents in place, and returns a subslice of the original slice
 func lastUniqueElements(list []string) []string {
 	totalSkip := 0
 	for i := len(list) - 1; i >= totalSkip; i-- {
diff --git a/cc/compiler.go b/cc/compiler.go
index 3b3bbbb1..102bc7a4 100644
--- a/cc/compiler.go
+++ b/cc/compiler.go
@@ -236,7 +236,7 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flag
 		flags.GlobalFlags = append(flags.GlobalFlags, "-I"+android.PathForModuleSrc(ctx).String())
 		flags.YasmFlags = append(flags.YasmFlags, "-I"+android.PathForModuleSrc(ctx).String())
 
-		if !(ctx.sdk() || ctx.vndk()) || ctx.Host() {
+		if !(ctx.useSdk() || ctx.useVndk()) || ctx.Host() {
 			flags.SystemIncludeFlags = append(flags.SystemIncludeFlags,
 				"${config.CommonGlobalIncludes}",
 				tc.IncludeFlags(),
@@ -244,7 +244,7 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flag
 		}
 	}
 
-	if ctx.sdk() {
+	if ctx.useSdk() {
 		// The NDK headers are installed to a common sysroot. While a more
 		// typical Soong approach would be to only make the headers for the
 		// library you're using available, we're trying to emulate the NDK
@@ -272,7 +272,7 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flag
 		flags.SystemIncludeFlags = append(flags.SystemIncludeFlags, "-isystem "+legacyIncludes)
 	}
 
-	if ctx.vndk() {
+	if ctx.useVndk() {
 		flags.GlobalFlags = append(flags.GlobalFlags,
 			"-D__ANDROID_API__=__ANDROID_API_FUTURE__", "-D__ANDROID_VNDK__")
 	}
@@ -366,7 +366,7 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flag
 		flags.GlobalFlags = append(flags.GlobalFlags, tc.ToolchainCflags())
 	}
 
-	if !ctx.sdk() {
+	if !ctx.useSdk() {
 		cStd := config.CStdVersion
 		if compiler.Properties.C_std == "experimental" {
 			cStd = config.ExperimentalCStdVersion
@@ -405,7 +405,7 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flag
 		flags.CppFlags = append([]string{"-std=" + cppStd}, flags.CppFlags...)
 	}
 
-	if ctx.vndk() {
+	if ctx.useVndk() {
 		flags.CFlags = append(flags.CFlags, esc(compiler.Properties.Target.Vendor.Cflags)...)
 	}
 
@@ -478,7 +478,7 @@ func (compiler *baseCompiler) hasSrcExt(ext string) bool {
 var gnuToCReplacer = strings.NewReplacer("gnu", "c")
 
 func ndkPathDeps(ctx ModuleContext) android.Paths {
-	if ctx.sdk() {
+	if ctx.useSdk() {
 		// The NDK sysroot timestamp file depends on all the NDK sysroot files
 		// (headers and libraries).
 		return android.Paths{getNdkSysrootTimestampFile(ctx)}
diff --git a/cc/installer.go b/cc/installer.go
index 027d191b..92076e50 100644
--- a/cc/installer.go
+++ b/cc/installer.go
@@ -69,7 +69,7 @@ func (installer *baseInstaller) installDir(ctx ModuleContext) android.OutputPath
 	if !ctx.Host() && !ctx.Arch().Native {
 		dir = filepath.Join(dir, ctx.Arch().ArchType.String())
 	}
-	if installer.location == InstallInData && ctx.vndk() {
+	if installer.location == InstallInData && ctx.useVndk() {
 		dir = filepath.Join(dir, "vendor")
 	}
 	return android.PathForModuleInstall(ctx, dir, installer.subDir, installer.Properties.Relative_install_path, installer.relative)
diff --git a/cc/library.go b/cc/library.go
index 151b63d2..e963ecba 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -156,7 +156,7 @@ type flagExporter struct {
 }
 
 func (f *flagExporter) exportedIncludes(ctx ModuleContext) android.Paths {
-	if ctx.vndk() && f.Properties.Target.Vendor.Export_include_dirs != nil {
+	if ctx.useVndk() && f.Properties.Target.Vendor.Export_include_dirs != nil {
 		return android.PathsForModuleSrc(ctx, f.Properties.Target.Vendor.Export_include_dirs)
 	} else {
 		return android.PathsForModuleSrc(ctx, f.Properties.Export_include_dirs)
@@ -435,7 +435,7 @@ func (library *libraryDecorator) linkerDeps(ctx DepsContext, deps Deps) Deps {
 		deps.SharedLibs = append(deps.SharedLibs, library.Properties.Static.Shared_libs...)
 	} else if library.shared() {
 		if ctx.toolchain().Bionic() && !Bool(library.baseLinker.Properties.Nocrt) {
-			if !ctx.sdk() {
+			if !ctx.useSdk() {
 				deps.CrtBegin = "crtbegin_so"
 				deps.CrtEnd = "crtend_so"
 			} else {
@@ -698,7 +698,7 @@ func (library *libraryDecorator) toc() android.OptionalPath {
 func (library *libraryDecorator) install(ctx ModuleContext, file android.Path) {
 	if library.shared() {
 		if ctx.Device() {
-			if ctx.vndk() {
+			if ctx.useVndk() {
 				if ctx.isVndkSp() {
 					library.baseInstaller.subDir = "vndk-sp"
 				} else if ctx.isVndk() {
diff --git a/cc/linker.go b/cc/linker.go
index 02d3ba5b..6ec56307 100644
--- a/cc/linker.go
+++ b/cc/linker.go
@@ -132,7 +132,7 @@ func (linker *baseLinker) linkerDeps(ctx BaseModuleContext, deps Deps) Deps {
 	deps.ReexportSharedLibHeaders = append(deps.ReexportSharedLibHeaders, linker.Properties.Export_shared_lib_headers...)
 	deps.ReexportGeneratedHeaders = append(deps.ReexportGeneratedHeaders, linker.Properties.Export_generated_headers...)
 
-	if ctx.vndk() {
+	if ctx.useVndk() {
 		deps.SharedLibs = removeListFromList(deps.SharedLibs, linker.Properties.Target.Vendor.Exclude_shared_libs)
 		deps.ReexportSharedLibHeaders = removeListFromList(deps.ReexportSharedLibHeaders, linker.Properties.Target.Vendor.Exclude_shared_libs)
 	}
@@ -174,7 +174,7 @@ func (linker *baseLinker) linkerDeps(ctx BaseModuleContext, deps Deps) Deps {
 			}
 
 			deps.LateSharedLibs = append(deps.LateSharedLibs, systemSharedLibs...)
-		} else if ctx.sdk() || ctx.vndk() {
+		} else if ctx.useSdk() || ctx.useVndk() {
 			deps.LateSharedLibs = append(deps.LateSharedLibs, "libc", "libm", "libdl")
 		}
 	}
@@ -242,7 +242,7 @@ func (linker *baseLinker) linkerFlags(ctx ModuleContext, flags Flags) Flags {
 		}
 	}
 
-	if ctx.sdk() && (ctx.Arch().ArchType != android.Mips && ctx.Arch().ArchType != android.Mips64) {
+	if ctx.useSdk() && (ctx.Arch().ArchType != android.Mips && ctx.Arch().ArchType != android.Mips64) {
 		// The bionic linker now has support gnu style hashes (which are much faster!), but shipping
 		// to older devices requires the old style hash. Fortunately, we can build with both and
 		// it'll work anywhere.
diff --git a/cc/object.go b/cc/object.go
index 59d523dd..402b1050 100644
--- a/cc/object.go
+++ b/cc/object.go
@@ -43,7 +43,7 @@ func objectFactory() android.Module {
 }
 
 func (object *objectLinker) appendLdflags(flags []string) {
-	panic(fmt.Errorf("appendLdflags on object Linker not supported"))
+	panic(fmt.Errorf("appendLdflags on objectLinker not supported"))
 }
 
 func (object *objectLinker) linkerProps() []interface{} {
diff --git a/cc/proto.go b/cc/proto.go
index a01951fe..6e3cce74 100644
--- a/cc/proto.go
+++ b/cc/proto.go
@@ -60,14 +60,14 @@ func protoDeps(ctx BaseModuleContext, deps Deps, p *android.ProtoProperties, sta
 
 	switch proptools.String(p.Proto.Type) {
 	case "full":
-		if ctx.sdk() {
+		if ctx.useSdk() {
 			lib = "libprotobuf-cpp-full-ndk"
 			static = true
 		} else {
 			lib = "libprotobuf-cpp-full"
 		}
 	case "lite", "":
-		if ctx.sdk() {
+		if ctx.useSdk() {
 			lib = "libprotobuf-cpp-lite-ndk"
 			static = true
 		} else {
diff --git a/cc/relocation_packer.go b/cc/relocation_packer.go
index c9f82ba8..d9b367c7 100644
--- a/cc/relocation_packer.go
+++ b/cc/relocation_packer.go
@@ -56,7 +56,7 @@ func (p *relocationPacker) packingInit(ctx BaseModuleContext) {
 	if ctx.AConfig().Getenv("DISABLE_RELOCATION_PACKER") == "true" {
 		enabled = false
 	}
-	if ctx.sdk() {
+	if ctx.useSdk() {
 		enabled = false
 	}
 	if p.Properties.Pack_relocations != nil &&
diff --git a/cc/rs.go b/cc/rs.go
index 976107ea..e7eb3bb5 100644
--- a/cc/rs.go
+++ b/cc/rs.go
@@ -82,7 +82,7 @@ func rsGenerateCpp(ctx android.ModuleContext, rsFiles android.Paths, rsFlags str
 
 func rsFlags(ctx ModuleContext, flags Flags, properties *BaseCompilerProperties) Flags {
 	targetApi := proptools.String(properties.Renderscript.Target_api)
-	if targetApi == "" && ctx.sdk() {
+	if targetApi == "" && ctx.useSdk() {
 		switch ctx.sdkVersion() {
 		case "current", "system_current", "test_current":
 			// Nothing
diff --git a/cc/sabi.go b/cc/sabi.go
index e45b0406..8086f5b6 100644
--- a/cc/sabi.go
+++ b/cc/sabi.go
@@ -79,7 +79,7 @@ func (sabimod *sabi) flags(ctx ModuleContext, flags Flags) Flags {
 
 func sabiDepsMutator(mctx android.TopDownMutatorContext) {
 	if c, ok := mctx.Module().(*Module); ok &&
-		((c.isVndk() && c.vndk()) || inList(c.Name(), llndkLibraries) ||
+		((c.isVndk() && c.useVndk()) || inList(c.Name(), llndkLibraries) ||
 			(c.sabi != nil && c.sabi.Properties.CreateSAbiDumps)) {
 		mctx.VisitDirectDeps(func(m blueprint.Module) {
 			tag := mctx.OtherModuleDependencyTag(m)
diff --git a/cc/sanitize.go b/cc/sanitize.go
index 090d4906..b8b5ffa5 100644
--- a/cc/sanitize.go
+++ b/cc/sanitize.go
@@ -128,7 +128,7 @@ func (sanitize *sanitize) begin(ctx BaseModuleContext) {
 	s := &sanitize.Properties.Sanitize
 
 	// Don't apply sanitizers to NDK code.
-	if ctx.sdk() {
+	if ctx.useSdk() {
 		s.Never = true
 	}
 
@@ -421,7 +421,7 @@ func (sanitize *sanitize) flags(ctx ModuleContext, flags Flags) Flags {
 
 		// When linking against VNDK, use the vendor variant of the runtime lib
 		sanitize.androidMkRuntimeLibrary = sanitize.runtimeLibrary
-		if ctx.vndk() {
+		if ctx.useVndk() {
 			sanitize.androidMkRuntimeLibrary = sanitize.runtimeLibrary + vendorSuffix
 		}
 	}
diff --git a/cc/stl.go b/cc/stl.go
index 17cde596..347db991 100644
--- a/cc/stl.go
+++ b/cc/stl.go
@@ -42,7 +42,7 @@ func (stl *stl) begin(ctx BaseModuleContext) {
 		if stl.Properties.Stl != nil {
 			s = *stl.Properties.Stl
 		}
-		if ctx.sdk() && ctx.Device() {
+		if ctx.useSdk() && ctx.Device() {
 			switch s {
 			case "":
 				return "ndk_system"
diff --git a/cc/test.go b/cc/test.go
index 12cc2adb..fa75f483 100644
--- a/cc/test.go
+++ b/cc/test.go
@@ -157,7 +157,7 @@ func (test *testDecorator) linkerFlags(ctx ModuleContext, flags Flags) Flags {
 
 func (test *testDecorator) linkerDeps(ctx BaseModuleContext, deps Deps) Deps {
 	if test.gtest() {
-		if ctx.sdk() && ctx.Device() {
+		if ctx.useSdk() && ctx.Device() {
 			switch ctx.selectedStl() {
 			case "ndk_libc++_shared", "ndk_libc++_static":
 				deps.StaticLibs = append(deps.StaticLibs, "libgtest_main_ndk_libcxx", "libgtest_ndk_libcxx")