Automated NDK API coverage used by Mainline modules build integration.

Add gen_ndk_usedby_apex.sh script to generate NDK API list used by Mainlain modules when modules get build.

Test: TARGET_BUILD_APPS=com.android.adbd m dist apps_only

Forrest run: android-build.googleplex.com/builds/forrest/run/L97800000742565481

Change-Id: I39e5aa7c74eff46aba06808642b2bd67ae45ba1e
diff --git a/apex/builder.go b/apex/builder.go
index b858135..744c20f 100644
--- a/apex/builder.go
+++ b/apex/builder.go
@@ -37,6 +37,7 @@
 
 func init() {
 	pctx.Import("android/soong/android")
+	pctx.Import("android/soong/cc/config")
 	pctx.Import("android/soong/java")
 	pctx.HostBinToolVariable("apexer", "apexer")
 	// ART minimal builds (using the master-art manifest) do not have the "frameworks/base"
@@ -65,6 +66,7 @@
 	pctx.HostBinToolVariable("extract_apks", "extract_apks")
 	pctx.HostBinToolVariable("make_f2fs", "make_f2fs")
 	pctx.HostBinToolVariable("sload_f2fs", "sload_f2fs")
+	pctx.SourcePathVariable("genNdkUsedbyApexPath", "build/soong/scripts/gen_ndk_usedby_apex.sh")
 }
 
 var (
@@ -176,6 +178,12 @@
 		Description: "Diff ${image_content_file} and ${allowed_files_file}",
 	}, "image_content_file", "allowed_files_file", "apex_module_name")
 
+	generateAPIsUsedbyApexRule = pctx.StaticRule("generateAPIsUsedbyApexRule", blueprint.RuleParams{
+		Command:     "$genNdkUsedbyApexPath ${image_dir} ${readelf} ${out}",
+		CommandDeps: []string{"${genNdkUsedbyApexPath}"},
+		Description: "Generate symbol list used by Apex",
+	}, "image_dir", "readelf")
+
 	// Don't add more rules here. Consider using android.NewRuleBuilder instead.
 )
 
@@ -675,6 +683,22 @@
 			Description: "apex proto convert",
 		})
 
+		implicitInputs = append(implicitInputs, unsignedOutputFile)
+
+		// Run coverage analysis
+		apisUsedbyOutputFile := android.PathForModuleOut(ctx, a.Name()+".txt")
+		ctx.Build(pctx, android.BuildParams{
+			Rule:        generateAPIsUsedbyApexRule,
+			Implicits:   implicitInputs,
+			Description: "coverage",
+			Output:      apisUsedbyOutputFile,
+			Args: map[string]string{
+				"image_dir": imageDir.String(),
+				"readelf":   "${config.ClangBin}/llvm-readelf",
+			},
+		})
+		a.coverageOutputPath = apisUsedbyOutputFile
+
 		bundleConfig := a.buildBundleConfig(ctx)
 
 		var abis []string