Ignore PrebuiltDepTag when processing APEX contents

When a source and a prebuilt module are present in the same build a
dependency is added from the source module to the prebuilt module.
Previously, the code for generating the APEX did not recognize that
tag and in some cases (e.g. for cc_(prebuilt_)library_shared) will
fail the build.

This change:
1) Adds a test to reproduce the problem.
2) Improves the debug message by pretty printing the tag.
3) Adds a new ExcludeFromApexContents interface that can be implemented
   by a tag to declare that it should be excluded from the APEX
   contents.
4) Ignores tags that implement that interface when generating APEX
   contents.
5) Implements that interface on prebuiltDependencyTag to fix the
   test.

Bug: 153326844
Bug: 153306490
Test: m nothing
Merged-In: I9dd4312c4f995c816c0a31d8d733eb5d7f56e1ea
Change-Id: I9dd4312c4f995c816c0a31d8d733eb5d7f56e1ea

android/apex.go

@@ -19,6 +19,8 @@ import (
 	"sort"
 	"strconv"
 	"sync"
+
+	"github.com/google/blueprint"
 )
 
 const (
@@ -117,6 +119,15 @@ type ApexProperties struct {
 	Info ApexInfo `blueprint:"mutated"`
 }
 
+// Marker interface that identifies dependencies that are excluded from APEX
+// contents.
+type ExcludeFromApexContentsTag interface {
+	blueprint.DependencyTag
+
+	// Method that differentiates this interface from others.
+	ExcludeFromApexContents()
+}
+
 // Provides default implementation for the ApexModule interface. APEX-aware
 // modules are expected to include this struct and call InitApexModule().
 type ApexModuleBase struct {

android/prebuilt.go

@@ -39,6 +39,12 @@ var PrebuiltDepTag prebuiltDependencyTag
 // Mark this tag so dependencies that use it are excluded from visibility enforcement.
 func (t prebuiltDependencyTag) ExcludeFromVisibilityEnforcement() {}
 
+// Mark this tag so dependencies that use it are excluded from APEX contents.
+func (t prebuiltDependencyTag) ExcludeFromApexContents() {}
+
+var _ ExcludeFromVisibilityEnforcementTag = PrebuiltDepTag
+var _ ExcludeFromApexContentsTag = PrebuiltDepTag
+
 type PrebuiltProperties struct {
 	// When prefer is set to true the prebuilt will be used instead of any source module with
 	// a matching name.

apex/apex.go

@@ -1985,6 +1985,9 @@ func (a *apexBundle) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	// TODO(jiyong) do this using walkPayloadDeps
 	ctx.WalkDepsBlueprint(func(child, parent blueprint.Module) bool {
 		depTag := ctx.OtherModuleDependencyTag(child)
+		if _, ok := depTag.(android.ExcludeFromApexContentsTag); ok {
+			return false
+		}
 		depName := ctx.OtherModuleName(child)
 		if _, isDirectDep := parent.(*apexBundle); isDirectDep {
 			switch depTag {
@@ -2146,7 +2149,7 @@ func (a *apexBundle) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 						filesInfo = append(filesInfo, apexFileForPrebuiltEtc(ctx, prebuilt, depName))
 					}
 				} else if am.CanHaveApexVariants() && am.IsInstallableToApex() {
-					ctx.ModuleErrorf("unexpected tag %q for indirect dependency %q", depTag, depName)
+					ctx.ModuleErrorf("unexpected tag %s for indirect dependency %q", PrettyPrintTag(depTag), depName)
 				}
 			}
 		}

apex/apex_test.go

@@ -141,6 +141,7 @@ func testApexContext(t *testing.T, bp string, handlers ...testCustomizer) (*andr
 		"my_include":                                 nil,
 		"foo/bar/MyClass.java":                       nil,
 		"prebuilt.jar":                               nil,
+		"prebuilt.so":                                nil,
 		"vendor/foo/devkeys/test.x509.pem":           nil,
 		"vendor/foo/devkeys/test.pk8":                nil,
 		"testkey.x509.pem":                           nil,
@@ -342,7 +343,7 @@ func TestBasicApex(t *testing.T) {
 			apex_available: [ "myapex" ],
 		}
 
-		cc_library {
+		cc_library_shared {
 			name: "mylib2",
 			srcs: ["mylib.cpp"],
 			system_shared_libs: [],
@@ -356,6 +357,16 @@ func TestBasicApex(t *testing.T) {
 			],
 		}
 
+		cc_prebuilt_library_shared {
+			name: "mylib2",
+			srcs: ["prebuilt.so"],
+			// TODO: remove //apex_available:platform
+			apex_available: [
+				"//apex_available:platform",
+				"myapex",
+			],
+    }
+
 		cc_library_static {
 			name: "libstatic",
 			srcs: ["mylib.cpp"],