Add basic VNDK support in Soong

Export a list of libraries in the VNDK, which is currently empty.

Take in Make's global BOARD_VNDK_VERSION, and use that as the SDK
version for modules that specify use_vndk: true.

Modules that use the vndk have some configuration as if they were
building against the NDK (the absence of globally defined headers), but
in other cases look like platform modules (using the platform libc++,
for now).

This change does not attempt to enforce any linking constraints, that
will come in a later patch.

Test: out/soong/build.ninja doesn't change
Change-Id: I3be206b67015ac5177b7eef4a451c579e3dc903f

cc/cc.go

@@ -125,6 +125,9 @@ type BaseProperties struct {
 	// Minimum sdk version supported when compiling against the ndk
 	Sdk_version string
 
+	// Whether to compile against the VNDK
+	Use_vndk bool
+
 	// don't insert default compiler flags into asflags, cflags,
 	// cppflags, conlyflags, ldflags, or include_dirs
 	No_default_compiler_flags *bool
@@ -132,6 +135,7 @@ type BaseProperties struct {
 	AndroidMkSharedLibs []string `blueprint:"mutated"`
 	HideFromMake        bool     `blueprint:"mutated"`
 	PreventInstall      bool     `blueprint:"mutated"`
+	Vndk_version        string   `blueprint:"mutated"`
 }
 
 type UnusedProperties struct {
@@ -147,6 +151,7 @@ type ModuleContextIntf interface {
 	noDefaultCompilerFlags() bool
 	sdk() bool
 	sdkVersion() string
+	vndk() bool
 	selectedStl() string
 	baseModuleName() string
 }
@@ -345,11 +350,22 @@ func (ctx *moduleContextImpl) sdk() bool {
 
 func (ctx *moduleContextImpl) sdkVersion() string {
 	if ctx.ctx.Device() {
-		return ctx.mod.Properties.Sdk_version
+		if ctx.mod.Properties.Use_vndk {
+			return ctx.mod.Properties.Vndk_version
+		} else {
+			return ctx.mod.Properties.Sdk_version
+		}
 	}
 	return ""
 }
 
+func (ctx *moduleContextImpl) vndk() bool {
+	if ctx.ctx.Device() {
+		return ctx.mod.Properties.Use_vndk
+	}
+	return false
+}
+
 func (ctx *moduleContextImpl) selectedStl() string {
 	if stl := ctx.mod.stl; stl != nil {
 		return stl.Properties.SelectedStl
@@ -493,11 +509,22 @@ func (c *Module) begin(ctx BaseModuleContext) {
 		feature.begin(ctx)
 	}
 	if ctx.sdk() {
+		if ctx.vndk() {
+			ctx.PropertyErrorf("use_vndk",
+				"sdk_version and use_vndk cannot be used at the same time")
+		}
+
 		version, err := normalizeNdkApiLevel(ctx.sdkVersion(), ctx.Arch())
 		if err != nil {
 			ctx.PropertyErrorf("sdk_version", err.Error())
 		}
 		c.Properties.Sdk_version = version
+	} else if ctx.vndk() {
+		version, err := normalizeNdkApiLevel(ctx.DeviceConfig().VndkVersion(), ctx.Arch())
+		if err != nil {
+			ctx.ModuleErrorf("Bad BOARD_VNDK_VERSION: %s", err.Error())
+		}
+		c.Properties.Vndk_version = version
 	}
 }
 
@@ -579,7 +606,7 @@ func (c *Module) DepsMutator(actx android.BottomUpMutatorContext) {
 
 	variantNdkLibs := []string{}
 	variantLateNdkLibs := []string{}
-	if ctx.sdk() {
+	if ctx.sdk() || ctx.vndk() {
 		version := ctx.sdkVersion()
 
 		// Rewrites the names of shared libraries into the names of the NDK