Add aconfig flags and a generic generated library plugin module for cc

The generated module lets us keep the aconfig code in its own pacakge
and not infect all of the cc package with aconfig. It's also closer
to what bazel is going to do

Bug: 283479529
Test: m aconfig_hello_world_cc && adb push $TOP/out/target/product/panther/system/bin/aconfig_hello_world_cc /system/bin && adb shell aconfig_hello_world_cc
Change-Id: I2fb9e419939c7ca77b111da9c376af077e2348a9

cc/Android.bp

@@ -32,6 +32,7 @@ bootstrap_go_package {
         "check.go",
         "coverage.go",
         "gen.go",
+        "generated_cc_library.go",
         "image.go",
         "linkable.go",
         "lto.go",

cc/cc.go

@@ -569,6 +569,24 @@ type feature interface {
 	props() []interface{}
 }
 
+// Information returned from Generator about the source code it's generating
+type GeneratedSource struct {
+	IncludeDirs    android.Paths
+	Sources        android.Paths
+	Headers        android.Paths
+	ReexportedDirs android.Paths
+}
+
+// generator allows injection of generated code
+type Generator interface {
+	GeneratorProps() []interface{}
+	GeneratorInit(ctx BaseModuleContext)
+	GeneratorDeps(ctx DepsContext, deps Deps) Deps
+	GeneratorFlags(ctx ModuleContext, flags Flags, deps PathDeps) Flags
+	GeneratorSources(ctx ModuleContext) GeneratedSource
+	GeneratorBuildActions(ctx ModuleContext, flags Flags, deps PathDeps)
+}
+
 // compiler is the interface for a compiler helper object. Different module decorators may implement
 // this helper differently.
 type compiler interface {
@@ -851,6 +869,7 @@ type Module struct {
 	// type-specific logic. These members may reference different objects or the same object.
 	// Functions of these decorators will be invoked to initialize and register type-specific
 	// build statements.
+	generators   []Generator
 	compiler     compiler
 	linker       linker
 	installer    installer
@@ -1201,6 +1220,9 @@ func (c *Module) VndkVersion() string {
 
 func (c *Module) Init() android.Module {
 	c.AddProperties(&c.Properties, &c.VendorProperties)
+	for _, generator := range c.generators {
+		c.AddProperties(generator.GeneratorProps()...)
+	}
 	if c.compiler != nil {
 		c.AddProperties(c.compiler.compilerProps()...)
 	}
@@ -2149,6 +2171,25 @@ func (c *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 		return
 	}
 
+	for _, generator := range c.generators {
+		gen := generator.GeneratorSources(ctx)
+		deps.IncludeDirs = append(deps.IncludeDirs, gen.IncludeDirs...)
+		deps.ReexportedDirs = append(deps.ReexportedDirs, gen.ReexportedDirs...)
+		deps.GeneratedDeps = append(deps.GeneratedDeps, gen.Headers...)
+		deps.ReexportedGeneratedHeaders = append(deps.ReexportedGeneratedHeaders, gen.Headers...)
+		deps.ReexportedDeps = append(deps.ReexportedDeps, gen.Headers...)
+		if len(deps.Objs.objFiles) == 0 {
+			// If we are reusuing object files (which happens when we're a shared library and we're
+			// reusing our static variant's object files), then skip adding the actual source files,
+			// because we already have the object for it.
+			deps.GeneratedSources = append(deps.GeneratedSources, gen.Sources...)
+		}
+	}
+
+	if ctx.Failed() {
+		return
+	}
+
 	if c.stubLibraryMultipleApexViolation(actx) {
 		actx.PropertyErrorf("apex_available",
 			"Stub libraries should have a single apex_available (test apexes excluded). Got %v", c.ApexAvailable())
@@ -2163,6 +2204,9 @@ func (c *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 		Toolchain: c.toolchain(ctx),
 		EmitXrefs: ctx.Config().EmitXrefRules(),
 	}
+	for _, generator := range c.generators {
+		flags = generator.GeneratorFlags(ctx, flags, deps)
+	}
 	if c.compiler != nil {
 		flags = c.compiler.compilerFlags(ctx, flags, deps)
 	}
@@ -2220,6 +2264,10 @@ func (c *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 
 	flags.AssemblerWithCpp = inList("-xassembler-with-cpp", flags.Local.AsFlags)
 
+	for _, generator := range c.generators {
+		generator.GeneratorBuildActions(ctx, flags, deps)
+	}
+
 	var objs Objects
 	if c.compiler != nil {
 		objs = c.compiler.compile(ctx, flags, deps)
@@ -2307,6 +2355,9 @@ func (c *Module) toolchain(ctx android.BaseModuleContext) config.Toolchain {
 }
 
 func (c *Module) begin(ctx BaseModuleContext) {
+	for _, generator := range c.generators {
+		generator.GeneratorInit(ctx)
+	}
 	if c.compiler != nil {
 		c.compiler.compilerInit(ctx)
 	}
@@ -2342,6 +2393,9 @@ func (c *Module) begin(ctx BaseModuleContext) {
 func (c *Module) deps(ctx DepsContext) Deps {
 	deps := Deps{}
 
+	for _, generator := range c.generators {
+		deps = generator.GeneratorDeps(ctx, deps)
+	}
 	if c.compiler != nil {
 		deps = c.compiler.compilerDeps(ctx, deps)
 	}

cc/generated_cc_library.go

@@ -0,0 +1,38 @@
+// Copyright 2023 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cc
+
+import (
+	"android/soong/android"
+)
+
+func GeneratedCcLibraryModuleFactory(moduleName string, callbacks Generator) android.Module {
+	module, _ := NewLibrary(android.HostAndDeviceSupported)
+
+	// Can be used as both a static and a shared library.
+	module.sdkMemberTypes = []android.SdkMemberType{
+		sharedLibrarySdkMemberType,
+		staticLibrarySdkMemberType,
+		staticAndSharedLibrarySdkMemberType,
+	}
+
+	//	TODO: Need to be bazelable
+	//	module.bazelable = true
+	//	module.bazelHandler = &ccLibraryBazelHandler{module: module}
+
+	module.generators = append(module.generators, callbacks)
+
+	return module.Init()
+}