Use libabigail to track NDK ABIs.

The local diffing behavior is currently flagged off so we can land
this in stages.

Test: pytest cc
Test: treehugger
Test: development/tools/update_ndk_abi.sh
Test: m ndk
Bug: http://b/156513478
Change-Id: Iccb314411bc74ea3ddfea8b85b0539709295f65a

cc/ndk_abi.go

@@ -0,0 +1,102 @@
+// 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"
+)
+
+func init() {
+	android.RegisterSingletonType("ndk_abi_dump", NdkAbiDumpSingleton)
+	android.RegisterSingletonType("ndk_abi_diff", NdkAbiDiffSingleton)
+}
+
+func getNdkAbiDumpInstallBase(ctx android.PathContext) android.OutputPath {
+	return android.PathForOutput(ctx).Join(ctx, "abi-dumps/ndk")
+}
+
+func getNdkAbiDumpTimestampFile(ctx android.PathContext) android.OutputPath {
+	return android.PathForOutput(ctx, "ndk_abi_dump.timestamp")
+}
+
+func NdkAbiDumpSingleton() android.Singleton {
+	return &ndkAbiDumpSingleton{}
+}
+
+type ndkAbiDumpSingleton struct{}
+
+func (n *ndkAbiDumpSingleton) GenerateBuildActions(ctx android.SingletonContext) {
+	var depPaths android.Paths
+	ctx.VisitAllModules(func(module android.Module) {
+		if !module.Enabled() {
+			return
+		}
+
+		if m, ok := module.(*Module); ok {
+			if installer, ok := m.installer.(*stubDecorator); ok {
+				if canDumpAbi(m) {
+					depPaths = append(depPaths, installer.abiDumpPath)
+				}
+			}
+		}
+	})
+
+	// `m dump-ndk-abi` will dump the NDK ABI.
+	// `development/tools/ndk/update_ndk_abi.sh` will dump the NDK ABI and
+	// update the golden copies in prebuilts/abi-dumps/ndk.
+	ctx.Build(pctx, android.BuildParams{
+		Rule:      android.Touch,
+		Output:    getNdkAbiDumpTimestampFile(ctx),
+		Implicits: depPaths,
+	})
+
+	ctx.Phony("dump-ndk-abi", getNdkAbiDumpTimestampFile(ctx))
+}
+
+func getNdkAbiDiffTimestampFile(ctx android.PathContext) android.WritablePath {
+	return android.PathForOutput(ctx, "ndk_abi_diff.timestamp")
+}
+
+func NdkAbiDiffSingleton() android.Singleton {
+	return &ndkAbiDiffSingleton{}
+}
+
+type ndkAbiDiffSingleton struct{}
+
+func (n *ndkAbiDiffSingleton) GenerateBuildActions(ctx android.SingletonContext) {
+	var depPaths android.Paths
+	ctx.VisitAllModules(func(module android.Module) {
+		if m, ok := module.(android.Module); ok && !m.Enabled() {
+			return
+		}
+
+		if m, ok := module.(*Module); ok {
+			if installer, ok := m.installer.(*stubDecorator); ok {
+				depPaths = append(depPaths, installer.abiDiffPaths...)
+			}
+		}
+	})
+
+	depPaths = append(depPaths, getNdkAbiDumpTimestampFile(ctx))
+
+	// `m diff-ndk-abi` will diff the NDK ABI.
+	ctx.Build(pctx, android.BuildParams{
+		Rule:      android.Touch,
+		Output:    getNdkAbiDiffTimestampFile(ctx),
+		Implicits: depPaths,
+	})
+
+	ctx.Phony("diff-ndk-abi", getNdkAbiDiffTimestampFile(ctx))
+}