Start using Providers instead of direct module access

Export information about static libraries, shared libraries and
exported flags through Providers instead of accessing the module
directly.  Much more is left to be converted, but this significantly
simplifies the dependencies on libraries with stubs by making it easy
for a module to masquerade as another by simply exporting the
providers from the other module.  Instead of depending on all the
versions of a library and then picking which one to use later, it
can depend only on the implementation variant and then select the
right SharedLibraryInfo from the variant.

Test: m checkbuild
Test: only expected changes to build.ninja
Change-Id: I1fd9eb4d251cf96ed8398d586efc3e0817663c76

rust/rust.go

@@ -302,9 +302,6 @@ type compiler interface {
 }
 
 type exportedFlagsProducer interface {
-	exportedLinkDirs() []string
-	exportedDepFlags() []string
-	exportedLinkObjects() []string
 	exportLinkDirs(...string)
 	exportDepFlags(...string)
 	exportLinkObjects(...string)
@@ -316,18 +313,6 @@ type flagExporter struct {
 	linkObjects []string
 }
 
-func (flagExporter *flagExporter) exportedLinkDirs() []string {
-	return flagExporter.linkDirs
-}
-
-func (flagExporter *flagExporter) exportedDepFlags() []string {
-	return flagExporter.depFlags
-}
-
-func (flagExporter *flagExporter) exportedLinkObjects() []string {
-	return flagExporter.linkObjects
-}
-
 func (flagExporter *flagExporter) exportLinkDirs(dirs ...string) {
 	flagExporter.linkDirs = android.FirstUniqueStrings(append(flagExporter.linkDirs, dirs...))
 }
@@ -340,16 +325,28 @@ func (flagExporter *flagExporter) exportLinkObjects(flags ...string) {
 	flagExporter.linkObjects = android.FirstUniqueStrings(append(flagExporter.linkObjects, flags...))
 }
 
+func (flagExporter *flagExporter) setProvider(ctx ModuleContext) {
+	ctx.SetProvider(FlagExporterInfoProvider, FlagExporterInfo{
+		Flags:       flagExporter.depFlags,
+		LinkDirs:    flagExporter.linkDirs,
+		LinkObjects: flagExporter.linkObjects,
+	})
+}
+
 var _ exportedFlagsProducer = (*flagExporter)(nil)
 
 func NewFlagExporter() *flagExporter {
-	return &flagExporter{
-		depFlags:    []string{},
-		linkDirs:    []string{},
-		linkObjects: []string{},
-	}
+	return &flagExporter{}
 }
 
+type FlagExporterInfo struct {
+	Flags       []string
+	LinkDirs    []string // TODO: this should be android.Paths
+	LinkObjects []string // TODO: this should be android.Paths
+}
+
+var FlagExporterInfoProvider = blueprint.NewProvider(FlagExporterInfo{})
+
 func (mod *Module) isCoverageVariant() bool {
 	return mod.coverage.Properties.IsCoverageVariant
 }
@@ -499,17 +496,6 @@ func (mod *Module) BuildSharedVariant() bool {
 	panic(fmt.Errorf("BuildSharedVariant called on non-library module: %q", mod.BaseModuleName()))
 }
 
-// Rust module deps don't have a link order (?)
-func (mod *Module) SetDepsInLinkOrder([]android.Path) {}
-
-func (mod *Module) GetDepsInLinkOrder() []android.Path {
-	return []android.Path{}
-}
-
-func (mod *Module) GetStaticVariant() cc.LinkableInterface {
-	return nil
-}
-
 func (mod *Module) Module() android.Module {
 	return mod
 }
@@ -532,12 +518,6 @@ func (mod *Module) InRecovery() bool {
 	// For now, Rust has no notion of the recovery image
 	return false
 }
-func (mod *Module) HasStaticVariant() bool {
-	if mod.GetStaticVariant() != nil {
-		return true
-	}
-	return false
-}
 
 func (mod *Module) CoverageFiles() android.Paths {
 	if mod.compiler != nil {
@@ -701,11 +681,6 @@ func (mod *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 		if mod.compiler.(libraryInterface).source() {
 			mod.sourceProvider.GenerateSource(ctx, deps)
 			mod.sourceProvider.setSubName(ctx.ModuleSubDir())
-			if lib, ok := mod.compiler.(*libraryDecorator); ok {
-				lib.flagExporter.linkDirs = nil
-				lib.flagExporter.linkObjects = nil
-				lib.flagExporter.depFlags = nil
-			}
 		} else {
 			sourceMod := actx.GetDirectDepWithTag(mod.Name(), sourceDepTag)
 			sourceLib := sourceMod.(*Module).compiler.(*libraryDecorator)
@@ -846,10 +821,11 @@ func (mod *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 			}
 
 			//Append the dependencies exportedDirs, except for proc-macros which target a different arch/OS
-			if lib, ok := rustDep.compiler.(exportedFlagsProducer); ok && depTag != procMacroDepTag {
-				depPaths.linkDirs = append(depPaths.linkDirs, lib.exportedLinkDirs()...)
-				depPaths.depFlags = append(depPaths.depFlags, lib.exportedDepFlags()...)
-				depPaths.linkObjects = append(depPaths.linkObjects, lib.exportedLinkObjects()...)
+			if depTag != procMacroDepTag {
+				exportedInfo := ctx.OtherModuleProvider(dep, FlagExporterInfoProvider).(FlagExporterInfo)
+				depPaths.linkDirs = append(depPaths.linkDirs, exportedInfo.LinkDirs...)
+				depPaths.depFlags = append(depPaths.depFlags, exportedInfo.Flags...)
+				depPaths.linkObjects = append(depPaths.linkObjects, exportedInfo.LinkObjects...)
 			}
 
 			if depTag == dylibDepTag || depTag == rlibDepTag || depTag == procMacroDepTag {
@@ -889,24 +865,22 @@ func (mod *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 			case cc.IsStaticDepTag(depTag):
 				depPaths.linkDirs = append(depPaths.linkDirs, linkPath)
 				depPaths.linkObjects = append(depPaths.linkObjects, linkObject.String())
-				depPaths.depIncludePaths = append(depPaths.depIncludePaths, ccDep.IncludeDirs()...)
-				if mod, ok := ccDep.(*cc.Module); ok {
-					depPaths.depSystemIncludePaths = append(depPaths.depSystemIncludePaths, mod.ExportedSystemIncludeDirs()...)
-					depPaths.depClangFlags = append(depPaths.depClangFlags, mod.ExportedFlags()...)
-					depPaths.depGeneratedHeaders = append(depPaths.depGeneratedHeaders, mod.ExportedGeneratedHeaders()...)
-				}
+				exportedInfo := ctx.OtherModuleProvider(dep, cc.FlagExporterInfoProvider).(cc.FlagExporterInfo)
+				depPaths.depIncludePaths = append(depPaths.depIncludePaths, exportedInfo.IncludeDirs...)
+				depPaths.depSystemIncludePaths = append(depPaths.depSystemIncludePaths, exportedInfo.SystemIncludeDirs...)
+				depPaths.depClangFlags = append(depPaths.depClangFlags, exportedInfo.Flags...)
+				depPaths.depGeneratedHeaders = append(depPaths.depGeneratedHeaders, exportedInfo.GeneratedHeaders...)
 				depPaths.coverageFiles = append(depPaths.coverageFiles, ccDep.CoverageFiles()...)
 				directStaticLibDeps = append(directStaticLibDeps, ccDep)
 				mod.Properties.AndroidMkStaticLibs = append(mod.Properties.AndroidMkStaticLibs, depName)
 			case cc.IsSharedDepTag(depTag):
 				depPaths.linkDirs = append(depPaths.linkDirs, linkPath)
 				depPaths.linkObjects = append(depPaths.linkObjects, linkObject.String())
-				depPaths.depIncludePaths = append(depPaths.depIncludePaths, ccDep.IncludeDirs()...)
-				if mod, ok := ccDep.(*cc.Module); ok {
-					depPaths.depSystemIncludePaths = append(depPaths.depSystemIncludePaths, mod.ExportedSystemIncludeDirs()...)
-					depPaths.depClangFlags = append(depPaths.depClangFlags, mod.ExportedFlags()...)
-					depPaths.depGeneratedHeaders = append(depPaths.depGeneratedHeaders, mod.ExportedGeneratedHeaders()...)
-				}
+				exportedInfo := ctx.OtherModuleProvider(dep, cc.FlagExporterInfoProvider).(cc.FlagExporterInfo)
+				depPaths.depIncludePaths = append(depPaths.depIncludePaths, exportedInfo.IncludeDirs...)
+				depPaths.depSystemIncludePaths = append(depPaths.depSystemIncludePaths, exportedInfo.SystemIncludeDirs...)
+				depPaths.depClangFlags = append(depPaths.depClangFlags, exportedInfo.Flags...)
+				depPaths.depGeneratedHeaders = append(depPaths.depGeneratedHeaders, exportedInfo.GeneratedHeaders...)
 				directSharedLibDeps = append(directSharedLibDeps, ccDep)
 				mod.Properties.AndroidMkSharedLibs = append(mod.Properties.AndroidMkSharedLibs, depName)
 				exportDep = true