Static variant of a stubs lib is correctly tracked

cc.Module.staticVariant is used to track the corresponding static
variant of a shared variant. This change fixes a problem that the
staticVariant field is not correctly set when the lib is with stubs:
{...}. This was happening because the staticVariant was set by adding
dependency from shared variant to static variant to reuse object files.
However, for a lib with stubs, the dependency was not created because it
does not make sense to share object files for stubs lib where source
code is auto-generated.

Fixing the issue by adding dependency to the static variant with a
different dependency tag whose only purpose is to set staticVariant
field.

Bug: 122885634
Test: m (cc_test amended)
Change-Id: I7f97cbb4c4a28bf9a93839d3b91ee140835aa6af

cc/cc.go

@@ -348,6 +348,7 @@ var (
 	linkerFlagsDepTag     = dependencyTag{name: "linker flags file"}
 	dynamicLinkerDepTag   = dependencyTag{name: "dynamic linker"}
 	reuseObjTag           = dependencyTag{name: "reuse objects"}
+	staticVariantTag      = dependencyTag{name: "static variant"}
 	ndkStubDepTag         = dependencyTag{name: "ndk stub", library: true}
 	ndkLateStubDepTag     = dependencyTag{name: "ndk late stub", library: true}
 	vndkExtDepTag         = dependencyTag{name: "vndk extends", library: true}
@@ -1536,6 +1537,13 @@ func (c *Module) depsToPaths(ctx android.ModuleContext) PathDeps {
 			}
 		}
 
+		if depTag == staticVariantTag {
+			if _, ok := ccDep.compiler.(libraryInterface); ok {
+				c.staticVariant = ccDep
+				return
+			}
+		}
+
 		// Extract explicitlyVersioned field from the depTag and reset it inside the struct.
 		// Otherwise, sharedDepTag and lateSharedDepTag with explicitlyVersioned set to true
 		// won't be matched to sharedDepTag and lateSharedDepTag.

cc/cc_test.go

@@ -215,6 +215,7 @@ func createTestContext(t *testing.T, config android.Config, bp string, os androi
 	ctx.RegisterModuleType("cc_binary", android.ModuleFactoryAdaptor(BinaryFactory))
 	ctx.RegisterModuleType("cc_library", android.ModuleFactoryAdaptor(LibraryFactory))
 	ctx.RegisterModuleType("cc_library_shared", android.ModuleFactoryAdaptor(LibrarySharedFactory))
+	ctx.RegisterModuleType("cc_library_static", android.ModuleFactoryAdaptor(LibraryStaticFactory))
 	ctx.RegisterModuleType("cc_library_headers", android.ModuleFactoryAdaptor(LibraryHeaderFactory))
 	ctx.RegisterModuleType("toolchain_library", android.ModuleFactoryAdaptor(ToolchainLibraryFactory))
 	ctx.RegisterModuleType("llndk_library", android.ModuleFactoryAdaptor(LlndkLibraryFactory))
@@ -1966,3 +1967,43 @@ func TestStaticExecutable(t *testing.T) {
 		}
 	}
 }
+
+func TestStaticDepsOrderWithStubs(t *testing.T) {
+	ctx := testCc(t, `
+		cc_binary {
+			name: "mybin",
+			srcs: ["foo.c"],
+			static_libs: ["libB"],
+			static_executable: true,
+			stl: "none",
+		}
+
+		cc_library {
+			name: "libB",
+			srcs: ["foo.c"],
+			shared_libs: ["libC"],
+			stl: "none",
+		}
+
+		cc_library {
+			name: "libC",
+			srcs: ["foo.c"],
+			stl: "none",
+			stubs: {
+				versions: ["1"],
+			},
+		}`)
+
+	mybin := ctx.ModuleForTests("mybin", "android_arm64_armv8-a_core").Module().(*Module)
+	actual := mybin.depsInLinkOrder
+	expected := getOutputPaths(ctx, "android_arm64_armv8-a_core_static", []string{"libB", "libC"})
+
+	if !reflect.DeepEqual(actual, expected) {
+		t.Errorf("staticDeps orderings were not propagated correctly"+
+			"\nactual:   %v"+
+			"\nexpected: %v",
+			actual,
+			expected,
+		)
+	}
+}

cc/library.go

@@ -1032,6 +1032,9 @@ func reuseStaticLibrary(mctx android.BottomUpMutatorContext, static, shared *Mod
 				sharedCompiler.baseCompiler.Properties.Srcs
 			sharedCompiler.baseCompiler.Properties.Srcs = nil
 			sharedCompiler.baseCompiler.Properties.Generated_sources = nil
+		} else {
+			// This dep is just to reference static variant from shared variant
+			mctx.AddInterVariantDependency(staticVariantTag, shared, static)
 		}
 	}
 }