Separate exported includes out of flags

Exported includes have been maintained along with other C/C++ flags.
This makes dependencies unclear, and users have had to parse flags to
get exported directories. This separates exported includes and
exported flags, thus making data more structured and explicit.

Bug: 132818174
Test: m
Change-Id: I5c25ac2224988c4a67e4db6fd6e4d39090b74041
diff --git a/cc/androidmk.go b/cc/androidmk.go
index 32ccf4c..272d3d4 100644
--- a/cc/androidmk.go
+++ b/cc/androidmk.go
@@ -156,12 +156,18 @@
 
 func (library *libraryDecorator) androidMkWriteExportedFlags(w io.Writer) {
 	exportedFlags := library.exportedFlags()
+	for _, dir := range library.exportedDirs() {
+		exportedFlags = append(exportedFlags, "-I"+dir)
+	}
+	for _, dir := range library.exportedSystemDirs() {
+		exportedFlags = append(exportedFlags, "-isystem "+dir)
+	}
 	if len(exportedFlags) > 0 {
 		fmt.Fprintln(w, "LOCAL_EXPORT_CFLAGS :=", strings.Join(exportedFlags, " "))
 	}
-	exportedFlagsDeps := library.exportedFlagsDeps()
-	if len(exportedFlagsDeps) > 0 {
-		fmt.Fprintln(w, "LOCAL_EXPORT_C_INCLUDE_DEPS :=", strings.Join(exportedFlagsDeps.Strings(), " "))
+	exportedDeps := library.exportedDeps()
+	if len(exportedDeps) > 0 {
+		fmt.Fprintln(w, "LOCAL_EXPORT_C_INCLUDE_DEPS :=", strings.Join(exportedDeps.Strings(), " "))
 	}
 }
 
diff --git a/cc/cc.go b/cc/cc.go
index 559fe4b..26d3d98 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -119,8 +119,13 @@
 	GeneratedSources android.Paths
 	GeneratedHeaders android.Paths
 
-	Flags, ReexportedFlags []string
-	ReexportedFlagsDeps    android.Paths
+	Flags                []string
+	IncludeDirs          []string
+	SystemIncludeDirs    []string
+	ReexportedDirs       []string
+	ReexportedSystemDirs []string
+	ReexportedFlags      []string
+	ReexportedDeps       android.Paths
 
 	// Paths to crt*.o files
 	CrtBegin, CrtEnd android.OptionalPath
@@ -988,6 +993,14 @@
 	flags.ConlyFlags, _ = filterList(flags.ConlyFlags, config.IllegalFlags)
 
 	flags.GlobalFlags = append(flags.GlobalFlags, deps.Flags...)
+
+	for _, dir := range deps.IncludeDirs {
+		flags.GlobalFlags = append(flags.GlobalFlags, "-I"+dir)
+	}
+	for _, dir := range deps.SystemIncludeDirs {
+		flags.GlobalFlags = append(flags.GlobalFlags, "-isystem "+dir)
+	}
+
 	c.flags = flags
 	// We need access to all the flags seen by a source file.
 	if c.sabi != nil {
@@ -1578,6 +1591,13 @@
 	llndkLibraries := llndkLibraries(ctx.Config())
 	vendorPublicLibraries := vendorPublicLibraries(ctx.Config())
 
+	reexportExporter := func(exporter exportedFlagsProducer) {
+		depPaths.ReexportedDirs = append(depPaths.ReexportedDirs, exporter.exportedDirs()...)
+		depPaths.ReexportedSystemDirs = append(depPaths.ReexportedSystemDirs, exporter.exportedSystemDirs()...)
+		depPaths.ReexportedFlags = append(depPaths.ReexportedFlags, exporter.exportedFlags()...)
+		depPaths.ReexportedDeps = append(depPaths.ReexportedDeps, exporter.exportedDeps()...)
+	}
+
 	ctx.VisitDirectDeps(func(dep android.Module) {
 		depName := ctx.OtherModuleName(dep)
 		depTag := ctx.OtherModuleDependencyTag(dep)
@@ -1599,14 +1619,13 @@
 				if genRule, ok := dep.(genrule.SourceFileGenerator); ok {
 					depPaths.GeneratedHeaders = append(depPaths.GeneratedHeaders,
 						genRule.GeneratedDeps()...)
-					flags := includeDirsToFlags(genRule.GeneratedHeaderDirs())
-					depPaths.Flags = append(depPaths.Flags, flags)
+					dirs := genRule.GeneratedHeaderDirs().Strings()
+					depPaths.IncludeDirs = append(depPaths.IncludeDirs, dirs...)
 					if depTag == genHeaderExportDepTag {
-						depPaths.ReexportedFlags = append(depPaths.ReexportedFlags, flags)
-						depPaths.ReexportedFlagsDeps = append(depPaths.ReexportedFlagsDeps,
-							genRule.GeneratedDeps()...)
+						depPaths.ReexportedDirs = append(depPaths.ReexportedDirs, dirs...)
+						depPaths.ReexportedDeps = append(depPaths.ReexportedDeps, genRule.GeneratedDeps()...)
 						// Add these re-exported flags to help header-abi-dumper to infer the abi exported by a library.
-						c.sabi.Properties.ReexportedIncludeFlags = append(c.sabi.Properties.ReexportedIncludeFlags, flags)
+						c.sabi.Properties.ReexportedIncludes = append(c.sabi.Properties.ReexportedIncludes, dirs...)
 
 					}
 				} else {
@@ -1644,10 +1663,9 @@
 		if depTag == reuseObjTag {
 			if l, ok := ccDep.compiler.(libraryInterface); ok {
 				c.staticVariant = ccDep
-				objs, flags, deps := l.reuseObjs()
+				objs, exporter := l.reuseObjs()
 				depPaths.Objs = depPaths.Objs.Append(objs)
-				depPaths.ReexportedFlags = append(depPaths.ReexportedFlags, flags...)
-				depPaths.ReexportedFlagsDeps = append(depPaths.ReexportedFlagsDeps, deps...)
+				reexportExporter(exporter)
 				return
 			}
 		}
@@ -1710,18 +1728,20 @@
 			}
 
 			if i, ok := ccDep.linker.(exportedFlagsProducer); ok {
-				flags := i.exportedFlags()
-				deps := i.exportedFlagsDeps()
-				depPaths.Flags = append(depPaths.Flags, flags...)
-				depPaths.GeneratedHeaders = append(depPaths.GeneratedHeaders, deps...)
+				depPaths.IncludeDirs = append(depPaths.IncludeDirs, i.exportedDirs()...)
+				depPaths.SystemIncludeDirs = append(depPaths.SystemIncludeDirs, i.exportedSystemDirs()...)
+				depPaths.GeneratedHeaders = append(depPaths.GeneratedHeaders, i.exportedDeps()...)
+				depPaths.Flags = append(depPaths.Flags, i.exportedFlags()...)
 
 				if t.reexportFlags {
-					depPaths.ReexportedFlags = append(depPaths.ReexportedFlags, flags...)
-					depPaths.ReexportedFlagsDeps = append(depPaths.ReexportedFlagsDeps, deps...)
+					reexportExporter(i)
 					// Add these re-exported flags to help header-abi-dumper to infer the abi exported by a library.
 					// Re-exported shared library headers must be included as well since they can help us with type information
 					// about template instantiations (instantiated from their headers).
-					c.sabi.Properties.ReexportedIncludeFlags = append(c.sabi.Properties.ReexportedIncludeFlags, flags...)
+					// -isystem headers are not included since for bionic libraries, abi-filtering is taken care of by version
+					// scripts.
+					c.sabi.Properties.ReexportedIncludes = append(
+						c.sabi.Properties.ReexportedIncludes, i.exportedDirs()...)
 				}
 			}
 
@@ -1883,12 +1903,16 @@
 
 	// Dedup exported flags from dependencies
 	depPaths.Flags = android.FirstUniqueStrings(depPaths.Flags)
+	depPaths.IncludeDirs = android.FirstUniqueStrings(depPaths.IncludeDirs)
+	depPaths.SystemIncludeDirs = android.FirstUniqueStrings(depPaths.SystemIncludeDirs)
 	depPaths.GeneratedHeaders = android.FirstUniquePaths(depPaths.GeneratedHeaders)
+	depPaths.ReexportedDirs = android.FirstUniqueStrings(depPaths.ReexportedDirs)
+	depPaths.ReexportedSystemDirs = android.FirstUniqueStrings(depPaths.ReexportedSystemDirs)
 	depPaths.ReexportedFlags = android.FirstUniqueStrings(depPaths.ReexportedFlags)
-	depPaths.ReexportedFlagsDeps = android.FirstUniquePaths(depPaths.ReexportedFlagsDeps)
+	depPaths.ReexportedDeps = android.FirstUniquePaths(depPaths.ReexportedDeps)
 
 	if c.sabi != nil {
-		c.sabi.Properties.ReexportedIncludeFlags = android.FirstUniqueStrings(c.sabi.Properties.ReexportedIncludeFlags)
+		c.sabi.Properties.ReexportedIncludes = android.FirstUniqueStrings(c.sabi.Properties.ReexportedIncludes)
 	}
 
 	return depPaths
diff --git a/cc/kernel_headers.go b/cc/kernel_headers.go
index c1da578..fff419e 100644
--- a/cc/kernel_headers.go
+++ b/cc/kernel_headers.go
@@ -25,9 +25,7 @@
 func (stub *kernelHeadersDecorator) link(ctx ModuleContext, flags Flags, deps PathDeps, objs Objects) android.Path {
 	if ctx.Device() {
 		f := &stub.libraryDecorator.flagExporter
-		for _, dir := range ctx.DeviceConfig().DeviceKernelHeaderDirs() {
-			f.flags = append(f.flags, "-isystem "+dir)
-		}
+		f.reexportSystemDirs(ctx.DeviceConfig().DeviceKernelHeaderDirs()...)
 	}
 	return stub.libraryDecorator.linkStatic(ctx, flags, deps, objs)
 }
diff --git a/cc/library.go b/cc/library.go
index d9c00dc..304a620 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -15,6 +15,7 @@
 package cc
 
 import (
+	"fmt"
 	"io"
 	"path/filepath"
 	"regexp"
@@ -207,8 +208,10 @@
 type flagExporter struct {
 	Properties FlagExporterProperties
 
-	flags     []string
-	flagsDeps android.Paths
+	dirs       []string
+	systemDirs []string
+	flags      []string
+	deps       android.Paths
 }
 
 func (f *flagExporter) exportedIncludes(ctx ModuleContext) android.Paths {
@@ -219,32 +222,57 @@
 	}
 }
 
-func (f *flagExporter) exportIncludes(ctx ModuleContext, inc string) {
-	includeDirs := f.exportedIncludes(ctx)
-	for _, dir := range includeDirs.Strings() {
-		f.flags = append(f.flags, inc+dir)
-	}
+func (f *flagExporter) exportIncludes(ctx ModuleContext) {
+	f.dirs = append(f.dirs, f.exportedIncludes(ctx).Strings()...)
 }
 
-func (f *flagExporter) reexportFlags(flags []string) {
+func (f *flagExporter) exportIncludesAsSystem(ctx ModuleContext) {
+	f.systemDirs = append(f.systemDirs, f.exportedIncludes(ctx).Strings()...)
+}
+
+func (f *flagExporter) reexportDirs(dirs ...string) {
+	f.dirs = append(f.dirs, dirs...)
+}
+
+func (f *flagExporter) reexportSystemDirs(dirs ...string) {
+	f.systemDirs = append(f.systemDirs, dirs...)
+}
+
+func (f *flagExporter) reexportFlags(flags ...string) {
+	for _, flag := range flags {
+		if strings.HasPrefix(flag, "-I") || strings.HasPrefix(flag, "-isystem") {
+			panic(fmt.Errorf("Exporting invalid flag %q: "+
+				"use reexportDirs or reexportSystemDirs to export directories", flag))
+		}
+	}
 	f.flags = append(f.flags, flags...)
 }
 
-func (f *flagExporter) reexportDeps(deps android.Paths) {
-	f.flagsDeps = append(f.flagsDeps, deps...)
+func (f *flagExporter) reexportDeps(deps ...android.Path) {
+	f.deps = append(f.deps, deps...)
+}
+
+func (f *flagExporter) exportedDirs() []string {
+	return f.dirs
+}
+
+func (f *flagExporter) exportedSystemDirs() []string {
+	return f.systemDirs
 }
 
 func (f *flagExporter) exportedFlags() []string {
 	return f.flags
 }
 
-func (f *flagExporter) exportedFlagsDeps() android.Paths {
-	return f.flagsDeps
+func (f *flagExporter) exportedDeps() android.Paths {
+	return f.deps
 }
 
 type exportedFlagsProducer interface {
+	exportedDirs() []string
+	exportedSystemDirs() []string
 	exportedFlags() []string
-	exportedFlagsDeps() android.Paths
+	exportedDeps() android.Paths
 }
 
 var _ exportedFlagsProducer = (*flagExporter)(nil)
@@ -256,9 +284,7 @@
 	MutatedProperties LibraryMutatedProperties
 
 	// For reusing static library objects for shared library
-	reuseObjects       Objects
-	reuseExportedFlags []string
-	reuseExportedDeps  android.Paths
+	reuseObjects Objects
 
 	// table-of-contents file to optimize out relinking when possible
 	tocFile android.OptionalPath
@@ -404,25 +430,6 @@
 	return flags
 }
 
-func extractExportIncludesFromFlags(flags []string) []string {
-	// This method is used in the  generation of rules which produce
-	// abi-dumps for source files. Exported headers are needed to infer the
-	// abi exported by a library and filter out the rest of the abi dumped
-	// from a source. We extract the include flags exported by a library.
-	// This includes the flags exported which are re-exported from static
-	// library dependencies, exported header library dependencies and
-	// generated header dependencies. -isystem headers are not included
-	// since for bionic libraries, abi-filtering is taken care of by version
-	// scripts.
-	var exportedIncludes []string
-	for _, flag := range flags {
-		if strings.HasPrefix(flag, "-I") {
-			exportedIncludes = append(exportedIncludes, flag)
-		}
-	}
-	return exportedIncludes
-}
-
 func (library *libraryDecorator) shouldCreateVndkSourceAbiDump(ctx ModuleContext) bool {
 	if library.Properties.Header_abi_checker.Enabled != nil {
 		return Bool(library.Properties.Header_abi_checker.Enabled)
@@ -455,8 +462,8 @@
 		for _, dir := range exportIncludeDirs.Strings() {
 			SourceAbiFlags = append(SourceAbiFlags, "-I"+dir)
 		}
-		for _, reexportedInclude := range extractExportIncludesFromFlags(library.sabi.Properties.ReexportedIncludeFlags) {
-			SourceAbiFlags = append(SourceAbiFlags, reexportedInclude)
+		for _, reexportedInclude := range library.sabi.Properties.ReexportedIncludes {
+			SourceAbiFlags = append(SourceAbiFlags, "-I"+reexportedInclude)
 		}
 		flags.SAbiFlags = SourceAbiFlags
 		total_length := len(library.baseCompiler.Properties.Srcs) + len(deps.GeneratedSources) + len(library.Properties.Shared.Srcs) +
@@ -486,7 +493,7 @@
 	getWholeStaticMissingDeps() []string
 	static() bool
 	objs() Objects
-	reuseObjs() (Objects, []string, android.Paths)
+	reuseObjs() (Objects, exportedFlagsProducer)
 	toc() android.OptionalPath
 
 	// Returns true if the build options for the module have selected a static or shared build
@@ -805,8 +812,8 @@
 		for _, dir := range exportIncludeDirs.Strings() {
 			SourceAbiFlags = append(SourceAbiFlags, "-I"+dir)
 		}
-		for _, reexportedInclude := range extractExportIncludesFromFlags(library.sabi.Properties.ReexportedIncludeFlags) {
-			SourceAbiFlags = append(SourceAbiFlags, reexportedInclude)
+		for _, reexportedInclude := range library.sabi.Properties.ReexportedIncludes {
+			SourceAbiFlags = append(SourceAbiFlags, "-I"+reexportedInclude)
 		}
 		exportedHeaderFlags := strings.Join(SourceAbiFlags, " ")
 		library.sAbiOutputFile = TransformDumpToLinkedDump(ctx, objs.sAbiDumpFiles, soFile, fileName, exportedHeaderFlags,
@@ -833,19 +840,17 @@
 		out = library.linkShared(ctx, flags, deps, objs)
 	}
 
-	library.exportIncludes(ctx, "-I")
-	library.reexportFlags(deps.ReexportedFlags)
-	library.reexportDeps(deps.ReexportedFlagsDeps)
+	library.exportIncludes(ctx)
+	library.reexportDirs(deps.ReexportedDirs...)
+	library.reexportSystemDirs(deps.ReexportedSystemDirs...)
+	library.reexportFlags(deps.ReexportedFlags...)
+	library.reexportDeps(deps.ReexportedDeps...)
 
 	if Bool(library.Properties.Aidl.Export_aidl_headers) {
 		if library.baseCompiler.hasSrcExt(".aidl") {
-			flags := []string{
-				"-I" + android.PathForModuleGen(ctx, "aidl").String(),
-			}
-			library.reexportFlags(flags)
-			library.reuseExportedFlags = append(library.reuseExportedFlags, flags...)
-			library.reexportDeps(library.baseCompiler.pathDeps) // TODO: restrict to aidl deps
-			library.reuseExportedDeps = append(library.reuseExportedDeps, library.baseCompiler.pathDeps...)
+			dir := android.PathForModuleGen(ctx, "aidl").String()
+			library.reexportDirs(dir)
+			library.reexportDeps(library.baseCompiler.pathDeps...) // TODO: restrict to aidl deps
 		}
 	}
 
@@ -853,26 +858,16 @@
 		if library.baseCompiler.hasSrcExt(".proto") {
 			includes := []string{}
 			if flags.proto.CanonicalPathFromRoot {
-				includes = append(includes, "-I"+flags.proto.SubDir.String())
+				includes = append(includes, flags.proto.SubDir.String())
 			}
-			includes = append(includes, "-I"+flags.proto.Dir.String())
-			library.reexportFlags(includes)
-			library.reuseExportedFlags = append(library.reuseExportedFlags, includes...)
-			library.reexportDeps(library.baseCompiler.pathDeps) // TODO: restrict to proto deps
-			library.reuseExportedDeps = append(library.reuseExportedDeps, library.baseCompiler.pathDeps...)
+			includes = append(includes, flags.proto.Dir.String())
+			library.reexportDirs(includes...)
+			library.reexportDeps(library.baseCompiler.pathDeps...) // TODO: restrict to proto deps
 		}
 	}
 
 	if library.baseCompiler.hasSrcExt(".sysprop") {
-		internalFlags := []string{
-			"-I" + android.PathForModuleGen(ctx, "sysprop", "include").String(),
-		}
-		systemFlags := []string{
-			"-I" + android.PathForModuleGen(ctx, "sysprop/system", "include").String(),
-		}
-
-		flags := internalFlags
-
+		dir := android.PathForModuleGen(ctx, "sysprop", "include").String()
 		if library.Properties.Sysprop.Platform != nil {
 			isProduct := ctx.ProductSpecific() && !ctx.useVndk()
 			isVendor := ctx.useVndk()
@@ -881,17 +876,16 @@
 			useSystem := isProduct || (isOwnerPlatform == isVendor)
 
 			if useSystem {
-				flags = systemFlags
+				dir = android.PathForModuleGen(ctx, "sysprop/system", "include").String()
 			}
 		}
 
-		library.reexportFlags(flags)
-		library.reexportDeps(library.baseCompiler.pathDeps)
-		library.reuseExportedFlags = append(library.reuseExportedFlags, flags...)
+		library.reexportDirs(dir)
+		library.reexportDeps(library.baseCompiler.pathDeps...)
 	}
 
 	if library.buildStubs() {
-		library.reexportFlags([]string{"-D" + versioningMacroName(ctx.ModuleName()) + "=" + library.stubsVersion()})
+		library.reexportFlags("-D" + versioningMacroName(ctx.ModuleName()) + "=" + library.stubsVersion())
 	}
 
 	return out
@@ -913,8 +907,8 @@
 	return library.objects
 }
 
-func (library *libraryDecorator) reuseObjs() (Objects, []string, android.Paths) {
-	return library.reuseObjects, library.reuseExportedFlags, library.reuseExportedDeps
+func (library *libraryDecorator) reuseObjs() (Objects, exportedFlagsProducer) {
+	return library.reuseObjects, &library.flagExporter
 }
 
 func (library *libraryDecorator) toc() android.OptionalPath {
diff --git a/cc/llndk_library.go b/cc/llndk_library.go
index 6cdf5c7..e8208ae 100644
--- a/cc/llndk_library.go
+++ b/cc/llndk_library.go
@@ -144,17 +144,17 @@
 			timestampFiles = append(timestampFiles, stub.processHeaders(ctx, dir, genHeaderOutDir))
 		}
 
-		includePrefix := "-I"
 		if Bool(stub.Properties.Export_headers_as_system) {
-			includePrefix = "-isystem "
+			stub.reexportSystemDirs(genHeaderOutDir.String())
+		} else {
+			stub.reexportDirs(genHeaderOutDir.String())
 		}
 
-		stub.reexportFlags([]string{includePrefix + genHeaderOutDir.String()})
-		stub.reexportDeps(timestampFiles)
+		stub.reexportDeps(timestampFiles...)
 	}
 
 	if Bool(stub.Properties.Export_headers_as_system) {
-		stub.exportIncludes(ctx, "-isystem ")
+		stub.exportIncludesAsSystem(ctx)
 		stub.libraryDecorator.flagExporter.Properties.Export_include_dirs = []string{}
 	}
 
diff --git a/cc/ndk_prebuilt.go b/cc/ndk_prebuilt.go
index fb16887..4356732 100644
--- a/cc/ndk_prebuilt.go
+++ b/cc/ndk_prebuilt.go
@@ -151,7 +151,7 @@
 		ctx.ModuleErrorf("NDK prebuilt libraries must have an ndk_lib prefixed name")
 	}
 
-	ndk.exportIncludes(ctx, "-isystem ")
+	ndk.exportIncludesAsSystem(ctx)
 
 	libName := strings.TrimPrefix(ctx.ModuleName(), "ndk_")
 	libExt := flags.Toolchain.ShlibSuffix()
diff --git a/cc/prebuilt.go b/cc/prebuilt.go
index f92c50d..dc6c43a 100644
--- a/cc/prebuilt.go
+++ b/cc/prebuilt.go
@@ -85,9 +85,11 @@
 	flags Flags, deps PathDeps, objs Objects) android.Path {
 	// TODO(ccross): verify shared library dependencies
 	if len(p.properties.Srcs) > 0 {
-		p.libraryDecorator.exportIncludes(ctx, "-I")
-		p.libraryDecorator.reexportFlags(deps.ReexportedFlags)
-		p.libraryDecorator.reexportDeps(deps.ReexportedFlagsDeps)
+		p.libraryDecorator.exportIncludes(ctx)
+		p.libraryDecorator.reexportDirs(deps.ReexportedDirs...)
+		p.libraryDecorator.reexportSystemDirs(deps.ReexportedSystemDirs...)
+		p.libraryDecorator.reexportFlags(deps.ReexportedFlags...)
+		p.libraryDecorator.reexportDeps(deps.ReexportedDeps...)
 
 		builderFlags := flagsToBuilderFlags(flags)
 
diff --git a/cc/sabi.go b/cc/sabi.go
index 451176f..ae7b31d 100644
--- a/cc/sabi.go
+++ b/cc/sabi.go
@@ -28,8 +28,8 @@
 )
 
 type SAbiProperties struct {
-	CreateSAbiDumps        bool `blueprint:"mutated"`
-	ReexportedIncludeFlags []string
+	CreateSAbiDumps    bool     `blueprint:"mutated"`
+	ReexportedIncludes []string `blueprint:"mutated"`
 }
 
 type sabi struct {
diff --git a/cc/util.go b/cc/util.go
index 3862728..2e1bb25 100644
--- a/cc/util.go
+++ b/cc/util.go
@@ -29,10 +29,6 @@
 	return android.JoinWithPrefix(dirs.Strings(), "-I")
 }
 
-func includeFilesToFlags(files android.Paths) string {
-	return android.JoinWithPrefix(files.Strings(), "-include ")
-}
-
 func ldDirsToFlags(dirs []string) string {
 	return android.JoinWithPrefix(dirs, "-L")
 }