Add support for native bridge trait

Adds a native bridge trait that if required will cause a
cc_library_header module to generate a cc_prebuilt_library_headers with
native_bridge_supported: true. It will fail if the cc_library_header's
native bridge variant would produce native bridge specific properties,
distinct from the other architecture variants, in the generated
cc_prebuilt_library_headers.

Bug: 195754365
Test: m nothing
Change-Id: I282fbb9095de6c6af57cca4eb4260e2c6c2da8cc

cc/Android.bp

@@ -63,6 +63,7 @@ bootstrap_go_package {
         "library.go",
         "library_headers.go",
         "library_sdk_member.go",
+        "native_bridge_sdk_trait.go",
         "object.go",
         "test.go",
         "toolchain_library.go",

cc/library_headers.go

@@ -33,6 +33,9 @@ var headersLibrarySdkMemberType = &librarySdkMemberType{
 		PropertyName:    "native_header_libs",
 		SupportsSdk:     true,
 		HostOsDependent: true,
+		Traits: []android.SdkMemberTrait{
+			nativeBridgeSdkTrait,
+		},
 	},
 	prebuiltModuleType: "cc_prebuilt_library_headers",
 	noOutputFiles:      true,

cc/library_sdk_member.go

@@ -75,8 +75,33 @@ type librarySdkMemberType struct {
 }
 
 func (mt *librarySdkMemberType) AddDependencies(ctx android.SdkDependencyContext, dependencyTag blueprint.DependencyTag, names []string) {
-	targets := ctx.MultiTargets()
+	// The base set of targets which does not include native bridge targets.
+	defaultTargets := ctx.MultiTargets()
+
+	// The lazily created list of native bridge targets.
+	var includeNativeBridgeTargets []android.Target
+
 	for _, lib := range names {
+		targets := defaultTargets
+
+		// If native bridge support is required in the sdk snapshot then add native bridge targets to
+		// the basic list of targets that are required.
+		nativeBridgeSupport := ctx.RequiresTrait(lib, nativeBridgeSdkTrait)
+		if nativeBridgeSupport && ctx.Device() {
+			// If not already computed then compute the list of native bridge targets.
+			if includeNativeBridgeTargets == nil {
+				includeNativeBridgeTargets = append([]android.Target{}, defaultTargets...)
+				allAndroidTargets := ctx.Config().Targets[android.Android]
+				for _, possibleNativeBridgeTarget := range allAndroidTargets {
+					if possibleNativeBridgeTarget.NativeBridge == android.NativeBridgeEnabled {
+						includeNativeBridgeTargets = append(includeNativeBridgeTargets, possibleNativeBridgeTarget)
+					}
+				}
+			}
+
+			// Include the native bridge targets as well.
+			targets = includeNativeBridgeTargets
+		}
 		for _, target := range targets {
 			name, version := StubsLibNameAndVersion(lib)
 			if version == "" {
@@ -122,6 +147,10 @@ func (mt *librarySdkMemberType) AddPrebuiltModule(ctx android.SdkMemberContext,
 
 	ccModule := member.Variants()[0].(*Module)
 
+	if ctx.RequiresTrait(nativeBridgeSdkTrait) {
+		pbm.AddProperty("native_bridge_supported", true)
+	}
+
 	if proptools.Bool(ccModule.Properties.Recovery_available) {
 		pbm.AddProperty("recovery_available", true)
 	}
@@ -436,7 +465,11 @@ func (p *nativeLibInfoProperties) PopulateFromVariant(ctx android.SdkMemberConte
 	exportedIncludeDirs, exportedGeneratedIncludeDirs := android.FilterPathListPredicate(
 		exportedInfo.IncludeDirs, isGeneratedHeaderDirectory)
 
-	p.archSubDir = ccModule.Target().Arch.ArchType.String()
+	target := ccModule.Target()
+	p.archSubDir = target.Arch.ArchType.String()
+	if target.NativeBridge == android.NativeBridgeEnabled {
+		p.archSubDir += "_native_bridge"
+	}
 
 	// Make sure that the include directories are unique.
 	p.ExportedIncludeDirs = android.FirstUniquePaths(exportedIncludeDirs)

cc/native_bridge_sdk_trait.go

@@ -0,0 +1,33 @@
+// Copyright 2021 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"
+
+// This file contains support for the native bridge sdk trait.
+
+func init() {
+	android.RegisterSdkMemberTrait(nativeBridgeSdkTrait)
+}
+
+type nativeBridgeSdkTraitStruct struct {
+	android.SdkMemberTraitBase
+}
+
+var nativeBridgeSdkTrait android.SdkMemberTrait = &nativeBridgeSdkTraitStruct{
+	SdkMemberTraitBase: android.SdkMemberTraitBase{
+		PropertyName: "native_bridge_support",
+	},
+}

sdk/cc_sdk_test.go

@@ -32,6 +32,23 @@ var ccTestFs = android.MockFS{
 	"some/where/stubslib.map.txt":     nil,
 }
 
+// Adds a native bridge target to the configured list of targets.
+var prepareForTestWithNativeBridgeTarget = android.FixtureModifyConfig(func(config android.Config) {
+	config.Targets[android.Android] = append(config.Targets[android.Android], android.Target{
+		Os: android.Android,
+		Arch: android.Arch{
+			ArchType:     android.Arm64,
+			ArchVariant:  "armv8-a",
+			CpuVariant:   "cpu",
+			Abi:          nil,
+			ArchFeatures: nil,
+		},
+		NativeBridge:             android.NativeBridgeEnabled,
+		NativeBridgeHostArchName: "x86_64",
+		NativeBridgeRelativePath: "native_bridge",
+	})
+})
+
 func testSdkWithCc(t *testing.T, bp string) *android.TestResult {
 	t.Helper()
 	return testSdkWithFs(t, bp, ccTestFs)
@@ -1979,6 +1996,91 @@ myinclude/Test.h -> include/myinclude/Test.h
 	)
 }
 
+func TestSnapshotWithCcHeadersLibraryAndNativeBridgeSupport(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		cc.PrepareForTestWithCcDefaultModules,
+		PrepareForTestWithSdkBuildComponents,
+		ccTestFs.AddToFixture(),
+		prepareForTestWithNativeBridgeTarget,
+	).RunTestWithBp(t, `
+		sdk {
+			name: "mysdk",
+			native_header_libs: ["mynativeheaders"],
+			traits: {
+				native_bridge_support: ["mynativeheaders"],
+			},
+		}
+
+		cc_library_headers {
+			name: "mynativeheaders",
+			export_include_dirs: ["myinclude"],
+			stl: "none",
+			system_shared_libs: [],
+			native_bridge_supported: true,
+		}
+	`)
+
+	CheckSnapshot(t, result, "mysdk", "",
+		checkUnversionedAndroidBpContents(`
+// This is auto-generated. DO NOT EDIT.
+
+cc_prebuilt_library_headers {
+    name: "mynativeheaders",
+    prefer: false,
+    visibility: ["//visibility:public"],
+    apex_available: ["//apex_available:platform"],
+    native_bridge_supported: true,
+    stl: "none",
+    compile_multilib: "both",
+    system_shared_libs: [],
+    export_include_dirs: ["include/myinclude"],
+}
+`),
+		checkAllCopyRules(`
+myinclude/Test.h -> include/myinclude/Test.h
+`),
+	)
+}
+
+// TestSnapshotWithCcHeadersLibrary_DetectsNativeBridgeSpecificProperties verifies that when a
+// module that has different output files for a native bridge target requests the native bridge
+// variants are copied into the sdk snapshot that it reports an error.
+func TestSnapshotWithCcHeadersLibrary_DetectsNativeBridgeSpecificProperties(t *testing.T) {
+	android.GroupFixturePreparers(
+		cc.PrepareForTestWithCcDefaultModules,
+		PrepareForTestWithSdkBuildComponents,
+		ccTestFs.AddToFixture(),
+		prepareForTestWithNativeBridgeTarget,
+	).ExtendWithErrorHandler(android.FixtureExpectsAtLeastOneErrorMatchingPattern(
+		`\QArchitecture variant "arm64_native_bridge" of sdk member "mynativeheaders" has properties distinct from other variants; this is not yet supported. The properties are:
+        export_include_dirs: [
+            "arm64_native_bridge/include/myinclude_nativebridge",
+            "arm64_native_bridge/include/myinclude",
+        ],\E`)).
+		RunTestWithBp(t, `
+		sdk {
+			name: "mysdk",
+			native_header_libs: ["mynativeheaders"],
+			traits: {
+				native_bridge_support: ["mynativeheaders"],
+			},
+		}
+
+		cc_library_headers {
+			name: "mynativeheaders",
+			export_include_dirs: ["myinclude"],
+			stl: "none",
+			system_shared_libs: [],
+			native_bridge_supported: true,
+			target: {
+				native_bridge: {
+					export_include_dirs: ["myinclude_nativebridge"],
+				},
+			},
+		}
+	`)
+}
+
 func TestHostSnapshotWithCcHeadersLibrary(t *testing.T) {
 	result := testSdkWithCc(t, `
 		sdk {