From f3c706868a6252ba50f7433e456935a3b25bc531 Mon Sep 17 00:00:00 2001
From: Nelson Li <nelsonli@google.com>
Date: Wed, 20 Dec 2023 02:37:52 +0000
Subject: [PATCH] Enable Soong to correctly add dependencies to .PHONY targets.

Previously, Soong's phony simply added "required" or "host_required"
to LOCAL_REQUIRED_MODULES and `include BUILD_PHONY_PACKAGE` without
correctly adding them to the dependency list.

This change add a new `phony_rule` module type to Soong that acts like
`.PHONY` instead of `BUILD_PHONY_PACKAGE`

Bug: 316838256
Bug: 309730110
Test: 1. Use `phony_rule` and adding "phony_deps: [dep_modules]" to
         Android.bp.
      2. make target and check the dep_modules be built.
Change-Id: I3e9e9ac26ecc456668f1b6baf5c08f9c9139b3b2
---
 android/androidmk.go |  1 +
 phony/phony.go       | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/android/androidmk.go b/android/androidmk.go
index a0ed1e449..004ae9edf 100644
--- a/android/androidmk.go
+++ b/android/androidmk.go
@@ -852,6 +852,7 @@ func translateAndroidModule(ctx SingletonContext, w io.Writer, mod blueprint.Mod
 		case "*java.SystemModules": // doesn't go through base_rules
 		case "*java.systemModulesImport": // doesn't go through base_rules
 		case "*phony.phony": // license properties written
+		case "*phony.PhonyRule": // writes phony deps and acts like `.PHONY`
 		case "*selinux.selinuxContextsModule": // license properties written
 		case "*sysprop.syspropLibrary": // license properties written
 		default:
diff --git a/phony/phony.go b/phony/phony.go
index a8b651aa8..bb4878899 100644
--- a/phony/phony.go
+++ b/phony/phony.go
@@ -24,6 +24,7 @@ import (
 
 func init() {
 	android.RegisterModuleType("phony", PhonyFactory)
+	android.RegisterModuleType("phony_rule", PhonyRuleFactory)
 }
 
 type phony struct {
@@ -71,3 +72,40 @@ func (p *phony) AndroidMk() android.AndroidMkData {
 		},
 	}
 }
+
+type PhonyRule struct {
+	android.ModuleBase
+
+	properties PhonyProperties
+}
+
+type PhonyProperties struct {
+	// The Phony_deps is the set of all dependencies for this target,
+	// and it can function similarly to .PHONY in a makefile.
+	// Additionally, dependencies within it can even include genrule.
+	Phony_deps []string
+}
+
+// The phony_rule provides functionality similar to the .PHONY in a makefile.
+// It can create a phony target and include relevant dependencies associated with it.
+func PhonyRuleFactory() android.Module {
+	module := &PhonyRule{}
+	android.InitAndroidModule(module)
+	module.AddProperties(&module.properties)
+	return module
+}
+
+func (p *PhonyRule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+}
+
+func (p *PhonyRule) AndroidMk() android.AndroidMkData {
+	return android.AndroidMkData{
+		Custom: func(w io.Writer, name, prefix, moduleDir string, data android.AndroidMkData) {
+			if len(p.properties.Phony_deps) > 0 {
+				depModulesStr := strings.Join(p.properties.Phony_deps, " ")
+				fmt.Fprintln(w, ".PHONY:", name)
+				fmt.Fprintln(w, name, ":", depModulesStr)
+			}
+		},
+	}
+}