Define Soong phony rules in Make

To support dist-for-goals in Soong, we need to define all phony rules
in Make so that dist-for-goals can insert additional dependencies on
them.  Collect all the phony rules in phonySingleton and write them
out as Make rules when Soong is embedded in Make, or as blueprint.Phony
rules when Soong is run standalone.

Test: m checkbuild
Change-Id: I68201eff30744b0f487fc4f11f033767b53a627d

9 files changed, 178 insertions, 80 deletions

diff --git a/android/Android.bp b/android/Android.bp
index 47dbc5d5f..487372bd8 100644
--- a/android/Android.bp
+++ b/android/Android.bp
@@ -36,6 +36,7 @@ bootstrap_go_package {
         "package_ctx.go",
         "path_properties.go",
         "paths.go",
+        "phony.go",
         "prebuilt.go",
         "proto.go",
         "register.go",
diff --git a/android/makevars.go b/android/makevars.go
index aba4ccec3..0acd0f665 100644
--- a/android/makevars.go
+++ b/android/makevars.go
@@ -17,12 +17,11 @@ package android
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
-	"os"
 	"strconv"
 	"strings"
 
 	"github.com/google/blueprint"
+	"github.com/google/blueprint/pathtools"
 	"github.com/google/blueprint/proptools"
 )
 
@@ -84,6 +83,11 @@ type MakeVarsContext interface {
 	// builder whenever a file matching the pattern as added or removed, without rerunning if a
 	// file that does not match the pattern is added to a searched directory.
 	GlobWithDeps(pattern string, excludes []string) ([]string, error)
+
+	// Phony creates a phony rule in Make, which will allow additional DistForGoal
+	// dependencies to be added to it.  Phony can be called on the same name multiple
+	// times to add additional dependencies.
+	Phony(names string, deps ...Path)
 }
 
 var _ PathContext = MakeVarsContext(nil)
@@ -130,9 +134,10 @@ var makeVarsProviders []makeVarsProvider
 
 type makeVarsContext struct {
 	SingletonContext
-	config Config
-	pctx   PackageContext
-	vars   []makeVarsVariable
+	config  Config
+	pctx    PackageContext
+	vars    []makeVarsVariable
+	phonies []phony
 }
 
 var _ MakeVarsContext = &makeVarsContext{}
@@ -144,6 +149,11 @@ type makeVarsVariable struct {
 	strict bool
 }
 
+type phony struct {
+	name string
+	deps []string
+}
+
 func (s *makeVarsSingleton) GenerateBuildActions(ctx SingletonContext) {
 	if !ctx.Config().EmbeddedInMake() {
 		return
@@ -152,11 +162,15 @@ func (s *makeVarsSingleton) GenerateBuildActions(ctx SingletonContext) {
 	outFile := absolutePath(PathForOutput(ctx,
 		"make_vars"+proptools.String(ctx.Config().productVariables.Make_suffix)+".mk").String())
 
+	lateOutFile := absolutePath(PathForOutput(ctx,
+		"late"+proptools.String(ctx.Config().productVariables.Make_suffix)+".mk").String())
+
 	if ctx.Failed() {
 		return
 	}
 
 	vars := []makeVarsVariable{}
+	var phonies []phony
 	for _, provider := range makeVarsProviders {
 		mctx := &makeVarsContext{
 			SingletonContext: ctx,
@@ -166,6 +180,7 @@ func (s *makeVarsSingleton) GenerateBuildActions(ctx SingletonContext) {
 		provider.call(mctx)
 
 		vars = append(vars, mctx.vars...)
+		phonies = append(phonies, mctx.phonies...)
 	}
 
 	if ctx.Failed() {
@@ -174,17 +189,16 @@ func (s *makeVarsSingleton) GenerateBuildActions(ctx SingletonContext) {
 
 	outBytes := s.writeVars(vars)
 
-	if _, err := os.Stat(absolutePath(outFile)); err == nil {
-		if data, err := ioutil.ReadFile(absolutePath(outFile)); err == nil {
-			if bytes.Equal(data, outBytes) {
-				return
-			}
-		}
+	if err := pathtools.WriteFileIfChanged(outFile, outBytes, 0666); err != nil {
+		ctx.Errorf(err.Error())
 	}
 
-	if err := ioutil.WriteFile(absolutePath(outFile), outBytes, 0666); err != nil {
+	lateOutBytes := s.writeLate(phonies)
+
+	if err := pathtools.WriteFileIfChanged(lateOutFile, lateOutBytes, 0666); err != nil {
 		ctx.Errorf(err.Error())
 	}
+
 }
 
 func (s *makeVarsSingleton) writeVars(vars []makeVarsVariable) []byte {
@@ -263,6 +277,26 @@ my_check_failed :=
 
 	fmt.Fprintln(buf, "\nsoong-compare-var :=")
 
+	fmt.Fprintln(buf)
+
+	return buf.Bytes()
+}
+
+func (s *makeVarsSingleton) writeLate(phonies []phony) []byte {
+	buf := &bytes.Buffer{}
+
+	fmt.Fprint(buf, `# Autogenerated file
+
+# Values written by Soong read after parsing all Android.mk files.
+
+
+`)
+
+	for _, phony := range phonies {
+		fmt.Fprintf(buf, ".PHONY: %s\n", phony.name)
+		fmt.Fprintf(buf, "%s: %s\n", phony.name, strings.Join(phony.deps, "\\\n  "))
+	}
+
 	return buf.Bytes()
 }
 
@@ -299,6 +333,10 @@ func (c *makeVarsContext) addVariable(name, ninjaStr string, strict, sort bool)
 	c.addVariableRaw(name, value, strict, sort)
 }
 
+func (c *makeVarsContext) addPhony(name string, deps []string) {
+	c.phonies = append(c.phonies, phony{name, deps})
+}
+
 func (c *makeVarsContext) Strict(name, ninjaStr string) {
 	c.addVariable(name, ninjaStr, true, false)
 }
@@ -318,3 +356,7 @@ func (c *makeVarsContext) CheckSorted(name, ninjaStr string) {
 func (c *makeVarsContext) CheckRaw(name, value string) {
 	c.addVariableRaw(name, value, false, false)
 }
+
+func (c *makeVarsContext) Phony(name string, deps ...Path) {
+	c.addPhony(name, Paths(deps).Strings())
+}
diff --git a/android/module.go b/android/module.go
index 82321f417..a488c0d77 100644
--- a/android/module.go
+++ b/android/module.go
@@ -207,6 +207,10 @@ type ModuleContext interface {
 	// Similar to blueprint.ModuleContext.Build, but takes Paths instead of []string,
 	// and performs more verification.
 	Build(pctx PackageContext, params BuildParams)
+	// Phony creates a Make-style phony rule, a rule with no commands that can depend on other
+	// phony rules or real files.  Phony can be called on the same name multiple times to add
+	// additional dependencies.
+	Phony(phony string, deps ...Path)
 
 	PrimaryModule() Module
 	FinalModule() Module
@@ -722,6 +726,7 @@ type ModuleBase struct {
 	installFiles       InstallPaths
 	checkbuildFiles    Paths
 	noticeFiles        Paths
+	phonies            map[string]Paths
 
 	// Used by buildTargetSingleton to create checkbuild and per-directory build targets
 	// Only set on the final variant of each module
@@ -1093,26 +1098,17 @@ func (m *ModuleBase) generateModuleTarget(ctx ModuleContext) {
 	}
 
 	if len(allInstalledFiles) > 0 {
-		name := PathForPhony(ctx, namespacePrefix+ctx.ModuleName()+"-install")
-		ctx.Build(pctx, BuildParams{
-			Rule:      blueprint.Phony,
-			Output:    name,
-			Implicits: allInstalledFiles.Paths(),
-			Default:   !ctx.Config().EmbeddedInMake(),
-		})
-		deps = append(deps, name)
-		m.installTarget = name
+		name := namespacePrefix + ctx.ModuleName() + "-install"
+		ctx.Phony(name, allInstalledFiles.Paths()...)
+		m.installTarget = PathForPhony(ctx, name)
+		deps = append(deps, m.installTarget)
 	}
 
 	if len(allCheckbuildFiles) > 0 {
-		name := PathForPhony(ctx, namespacePrefix+ctx.ModuleName()+"-checkbuild")
-		ctx.Build(pctx, BuildParams{
-			Rule:      blueprint.Phony,
-			Output:    name,
-			Implicits: allCheckbuildFiles,
-		})
-		deps = append(deps, name)
-		m.checkbuildTarget = name
+		name := namespacePrefix + ctx.ModuleName() + "-checkbuild"
+		ctx.Phony(name, allCheckbuildFiles...)
+		m.checkbuildTarget = PathForPhony(ctx, name)
+		deps = append(deps, m.checkbuildTarget)
 	}
 
 	if len(deps) > 0 {
@@ -1121,12 +1117,7 @@ func (m *ModuleBase) generateModuleTarget(ctx ModuleContext) {
 			suffix = "-soong"
 		}
 
-		name := PathForPhony(ctx, namespacePrefix+ctx.ModuleName()+suffix)
-		ctx.Build(pctx, BuildParams{
-			Rule:      blueprint.Phony,
-			Outputs:   []WritablePath{name},
-			Implicits: deps,
-		})
+		ctx.Phony(namespacePrefix+ctx.ModuleName()+suffix, deps...)
 
 		m.blueprintDir = ctx.ModuleDir()
 	}
@@ -1313,6 +1304,9 @@ func (m *ModuleBase) GenerateBuildActions(blueprintCtx blueprint.ModuleContext)
 		m.checkbuildFiles = append(m.checkbuildFiles, ctx.checkbuildFiles...)
 		m.initRcPaths = PathsForModuleSrc(ctx, m.commonProperties.Init_rc)
 		m.vintfFragmentsPaths = PathsForModuleSrc(ctx, m.commonProperties.Vintf_fragments)
+		for k, v := range ctx.phonies {
+			m.phonies[k] = append(m.phonies[k], v...)
+		}
 	} else if ctx.Config().AllowMissingDependencies() {
 		// If the module is not enabled it will not create any build rules, nothing will call
 		// ctx.GetMissingDependencies(), and blueprint will consider the missing dependencies to be unhandled
@@ -1460,6 +1454,7 @@ type moduleContext struct {
 	installFiles    InstallPaths
 	checkbuildFiles Paths
 	module          Module
+	phonies         map[string]Paths
 
 	// For tests
 	buildParams []BuildParams
@@ -1574,6 +1569,11 @@ func (m *moduleContext) Build(pctx PackageContext, params BuildParams) {
 
 	m.bp.Build(pctx.PackageContext, convertBuildParams(params))
 }
+
+func (m *moduleContext) Phony(name string, deps ...Path) {
+	addPhony(m.config, name, deps...)
+}
+
 func (m *moduleContext) GetMissingDependencies() []string {
 	var missingDeps []string
 	missingDeps = append(missingDeps, m.Module().base().commonProperties.MissingDeps...)
@@ -2233,9 +2233,8 @@ type buildTargetSingleton struct{}
 func (c *buildTargetSingleton) GenerateBuildActions(ctx SingletonContext) {
 	var checkbuildDeps Paths
 
-	mmTarget := func(dir string) WritablePath {
-		return PathForPhony(ctx,
-			"MODULES-IN-"+strings.Replace(filepath.Clean(dir), "/", "-", -1))
+	mmTarget := func(dir string) string {
+		return "MODULES-IN-" + strings.Replace(filepath.Clean(dir), "/", "-", -1)
 	}
 
 	modulesInDir := make(map[string]Paths)
@@ -2261,11 +2260,7 @@ func (c *buildTargetSingleton) GenerateBuildActions(ctx SingletonContext) {
 	}
 
 	// Create a top-level checkbuild target that depends on all modules
-	ctx.Build(pctx, BuildParams{
-		Rule:      blueprint.Phony,
-		Output:    PathForPhony(ctx, "checkbuild"+suffix),
-		Implicits: checkbuildDeps,
-	})
+	ctx.Phony("checkbuild"+suffix, checkbuildDeps...)
 
 	// Make will generate the MODULES-IN-* targets
 	if ctx.Config().EmbeddedInMake() {
@@ -2289,7 +2284,7 @@ func (c *buildTargetSingleton) GenerateBuildActions(ctx SingletonContext) {
 	for _, dir := range dirs {
 		p := parentDir(dir)
 		if p != "." && p != "/" {
-			modulesInDir[p] = append(modulesInDir[p], mmTarget(dir))
+			modulesInDir[p] = append(modulesInDir[p], PathForPhony(ctx, mmTarget(dir)))
 		}
 	}
 
@@ -2297,14 +2292,7 @@ func (c *buildTargetSingleton) GenerateBuildActions(ctx SingletonContext) {
 	// depends on the MODULES-IN-* targets of all of its subdirectories that contain Android.bp
 	// files.
 	for _, dir := range dirs {
-		ctx.Build(pctx, BuildParams{
-			Rule:      blueprint.Phony,
-			Output:    mmTarget(dir),
-			Implicits: modulesInDir[dir],
-			// HACK: checkbuild should be an optional build, but force it
-			// enabled for now in standalone builds
-			Default: !ctx.Config().EmbeddedInMake(),
-		})
+		ctx.Phony(mmTarget(dir), modulesInDir[dir]...)
 	}
 
 	// Create (host|host-cross|target)-<OS> phony rules to build a reduced checkbuild.
@@ -2331,23 +2319,15 @@ func (c *buildTargetSingleton) GenerateBuildActions(ctx SingletonContext) {
 			continue
 		}
 
-		name := PathForPhony(ctx, className+"-"+os.Name)
-		osClass[className] = append(osClass[className], name)
+		name := className + "-" + os.Name
+		osClass[className] = append(osClass[className], PathForPhony(ctx, name))
 
-		ctx.Build(pctx, BuildParams{
-			Rule:      blueprint.Phony,
-			Output:    name,
-			Implicits: deps,
-		})
+		ctx.Phony(name, deps...)
 	}
 
 	// Wrap those into host|host-cross|target phony rules
 	for _, class := range SortedStringKeys(osClass) {
-		ctx.Build(pctx, BuildParams{
-			Rule:      blueprint.Phony,
-			Output:    PathForPhony(ctx, class),
-			Implicits: osClass[class],
-		})
+		ctx.Phony(class, osClass[class]...)
 	}
 }
 
diff --git a/android/phony.go b/android/phony.go
new file mode 100644
index 000000000..f8e5a4401
--- /dev/null
+++ b/android/phony.go
@@ -0,0 +1,75 @@
+// Copyright 2020 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 android
+
+import (
+	"sync"
+
+	"github.com/google/blueprint"
+)
+
+var phonyMapOnceKey = NewOnceKey("phony")
+
+type phonyMap map[string]Paths
+
+var phonyMapLock sync.Mutex
+
+func getPhonyMap(config Config) phonyMap {
+	return config.Once(phonyMapOnceKey, func() interface{} {
+		return make(phonyMap)
+	}).(phonyMap)
+}
+
+func addPhony(config Config, name string, deps ...Path) {
+	phonyMap := getPhonyMap(config)
+	phonyMapLock.Lock()
+	defer phonyMapLock.Unlock()
+	phonyMap[name] = append(phonyMap[name], deps...)
+}
+
+type phonySingleton struct {
+	phonyMap  phonyMap
+	phonyList []string
+}
+
+var _ SingletonMakeVarsProvider = (*phonySingleton)(nil)
+
+func (p *phonySingleton) GenerateBuildActions(ctx SingletonContext) {
+	p.phonyMap = getPhonyMap(ctx.Config())
+	p.phonyList = SortedStringKeys(p.phonyMap)
+	for _, phony := range p.phonyList {
+		p.phonyMap[phony] = SortedUniquePaths(p.phonyMap[phony])
+	}
+
+	if !ctx.Config().EmbeddedInMake() {
+		for _, phony := range p.phonyList {
+			ctx.Build(pctx, BuildParams{
+				Rule:      blueprint.Phony,
+				Outputs:   []WritablePath{PathForPhony(ctx, phony)},
+				Implicits: p.phonyMap[phony],
+			})
+		}
+	}
+}
+
+func (p phonySingleton) MakeVars(ctx MakeVarsContext) {
+	for _, phony := range p.phonyList {
+		ctx.Phony(phony, p.phonyMap[phony]...)
+	}
+}
+
+func phonySingletonFactory() Singleton {
+	return &phonySingleton{}
+}
diff --git a/android/register.go b/android/register.go
index ccfe01e74..036a8113f 100644
--- a/android/register.go
+++ b/android/register.go
@@ -104,6 +104,9 @@ func (ctx *Context) Register() {
 
 	registerMutators(ctx.Context, preArch, preDeps, postDeps, finalDeps)
 
+	// Register phony just before makevars so it can write out its phony rules as Make rules
+	ctx.RegisterSingletonType("phony", SingletonFactoryAdaptor(phonySingletonFactory))
+
 	// Register makevars after other singletons so they can export values through makevars
 	ctx.RegisterSingletonType("makevars", SingletonFactoryAdaptor(makeVarsSingletonFunc))
 
diff --git a/android/singleton.go b/android/singleton.go
index 568398cdd..2c51c6c48 100644
--- a/android/singleton.go
+++ b/android/singleton.go
@@ -36,6 +36,12 @@ type SingletonContext interface {
 	Variable(pctx PackageContext, name, value string)
 	Rule(pctx PackageContext, name string, params blueprint.RuleParams, argNames ...string) blueprint.Rule
 	Build(pctx PackageContext, params BuildParams)
+
+	// Phony creates a Make-style phony rule, a rule with no commands that can depend on other
+	// phony rules or real files.  Phony can be called on the same name multiple times to add
+	// additional dependencies.
+	Phony(name string, deps ...Path)
+
 	RequireNinjaVersion(major, minor, micro int)
 
 	// SetNinjaBuildDir sets the value of the top-level "builddir" Ninja variable
@@ -156,6 +162,10 @@ func (s *singletonContextAdaptor) Build(pctx PackageContext, params BuildParams)
 
 }
 
+func (s *singletonContextAdaptor) Phony(name string, deps ...Path) {
+	addPhony(s.Config(), name, deps...)
+}
+
 func (s *singletonContextAdaptor) SetNinjaBuildDir(pctx PackageContext, value string) {
 	s.SingletonContext.SetNinjaBuildDir(pctx.PackageContext, value)
 }
diff --git a/android/writedocs.go b/android/writedocs.go
index 7262ad810..9e43e80a6 100644
--- a/android/writedocs.go
+++ b/android/writedocs.go
@@ -69,9 +69,5 @@ func (c *docsSingleton) GenerateBuildActions(ctx SingletonContext) {
 	})
 
 	// Add a phony target for building the documentation
-	ctx.Build(pctx, BuildParams{
-		Rule:   blueprint.Phony,
-		Output: PathForPhony(ctx, "soong_docs"),
-		Input:  docsFile,
-	})
+	ctx.Phony("soong_docs", docsFile)
 }
diff --git a/cc/cc.go b/cc/cc.go
index 8eabff516..31d35e1bb 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -3230,12 +3230,7 @@ func (ks *kytheExtractAllSingleton) GenerateBuildActions(ctx android.SingletonCo
 	})
 	// TODO(asmundak): Perhaps emit a rule to output a warning if there were no xrefTargets
 	if len(xrefTargets) > 0 {
-		ctx.Build(pctx, android.BuildParams{
-			Rule:   blueprint.Phony,
-			Output: android.PathForPhony(ctx, "xref_cxx"),
-			Inputs: xrefTargets,
-			//Default: true,
-		})
+		ctx.Phony("xref_cxx", xrefTargets...)
 	}
 }
 
diff --git a/java/java.go b/java/java.go
index af68e56b7..9a352dbe0 100644
--- a/java/java.go
+++ b/java/java.go
@@ -2863,11 +2863,7 @@ func (ks *kytheExtractJavaSingleton) GenerateBuildActions(ctx android.SingletonC
 	})
 	// TODO(asmundak): perhaps emit a rule to output a warning if there were no xrefTargets
 	if len(xrefTargets) > 0 {
-		ctx.Build(pctx, android.BuildParams{
-			Rule:   blueprint.Phony,
-			Output: android.PathForPhony(ctx, "xref_java"),
-			Inputs: xrefTargets,
-		})
+		ctx.Phony("xref_java", xrefTargets...)
 	}
 }