Convert cc aidl to rule builder

This fixes an incremental build issue where we didn't clean up old aidl
header files (or necessarily notice that they were updated).

We do this by declaring the header files as outputs in the build graph,
but this means that the src file name needs to be convertible to the
aidl package name, as that's how the header file paths are created. In
many cases, filegroups can be used to strip path prefixes from the aidl
files.

Bug: 112114177
Test: treehugger
Change-Id: If534ff3dbfac329dea9a7402e30be74495754160

2 files changed, 45 insertions, 25 deletions

diff --git a/cc/gen.go b/cc/gen.go
index ae761d036..82669acc7 100644
--- a/cc/gen.go
+++ b/cc/gen.go
@@ -16,6 +16,7 @@ package cc
 
 import (
 	"path/filepath"
+	"strings"
 
 	"github.com/google/blueprint"
 
@@ -36,15 +37,6 @@ var (
 			CommandDeps: []string{"$lexCmd"},
 		})
 
-	aidl = pctx.AndroidStaticRule("aidl",
-		blueprint.RuleParams{
-			Command:     "$aidlCmd -d${out}.d --ninja $aidlFlags $in $outDir $out",
-			CommandDeps: []string{"$aidlCmd"},
-			Depfile:     "${out}.d",
-			Deps:        blueprint.DepsGCC,
-		},
-		"aidlFlags", "outDir")
-
 	sysprop = pctx.AndroidStaticRule("sysprop",
 		blueprint.RuleParams{
 			Command: "$syspropCmd --header-dir=$headerOutDir --system-header-dir=$systemOutDir " +
@@ -114,20 +106,37 @@ func genYacc(ctx android.ModuleContext, rule *android.RuleBuilder, yaccFile andr
 	return ret
 }
 
-func genAidl(ctx android.ModuleContext, aidlFile android.Path, outFile android.ModuleGenPath, aidlFlags string) android.Paths {
-	ctx.Build(pctx, android.BuildParams{
-		Rule:        aidl,
-		Description: "aidl " + aidlFile.Rel(),
-		Output:      outFile,
-		Input:       aidlFile,
-		Args: map[string]string{
-			"aidlFlags": aidlFlags,
-			"outDir":    android.PathForModuleGen(ctx, "aidl").String(),
-		},
-	})
+func genAidl(ctx android.ModuleContext, rule *android.RuleBuilder, aidlFile android.Path,
+	outFile, depFile android.ModuleGenPath, aidlFlags string) android.Paths {
+
+	aidlPackage := strings.TrimSuffix(aidlFile.Rel(), aidlFile.Base())
+	baseName := strings.TrimSuffix(aidlFile.Base(), aidlFile.Ext())
+	shortName := strings.TrimPrefix(baseName, "I")
 
-	// TODO: This should return the generated headers, not the source file.
-	return android.Paths{outFile}
+	outDir := android.PathForModuleGen(ctx, "aidl")
+	headerI := outDir.Join(ctx, aidlPackage, baseName+".h")
+	headerBn := outDir.Join(ctx, aidlPackage, "Bn"+shortName+".h")
+	headerBp := outDir.Join(ctx, aidlPackage, "Bp"+shortName+".h")
+
+	cmd := rule.Command()
+	cmd.Tool(ctx.Config().HostToolPath(ctx, "aidl-cpp")).
+		FlagWithDepFile("-d", depFile).
+		Flag("--ninja").
+		Flag(aidlFlags).
+		Input(aidlFile).
+		OutputDir().
+		Output(outFile).
+		ImplicitOutputs(android.WritablePaths{
+			headerI,
+			headerBn,
+			headerBp,
+		})
+
+	return android.Paths{
+		headerI,
+		headerBn,
+		headerBp,
+	}
 }
 
 func genLex(ctx android.ModuleContext, lexFile android.Path, outFile android.ModuleGenPath) {
@@ -187,6 +196,8 @@ func genSources(ctx android.ModuleContext, srcFiles android.Paths,
 	var deps android.Paths
 	var rsFiles android.Paths
 
+	var aidlRule *android.RuleBuilder
+
 	var yaccRule_ *android.RuleBuilder
 	yaccRule := func() *android.RuleBuilder {
 		if yaccRule_ == nil {
@@ -218,9 +229,13 @@ func genSources(ctx android.ModuleContext, srcFiles android.Paths,
 			srcFiles[i] = ccFile
 			deps = append(deps, headerFile)
 		case ".aidl":
+			if aidlRule == nil {
+				aidlRule = android.NewRuleBuilder().Sbox(android.PathForModuleGen(ctx, "aidl"))
+			}
 			cppFile := android.GenPathWithExt(ctx, "aidl", srcFile, "cpp")
+			depFile := android.GenPathWithExt(ctx, "aidl", srcFile, "cpp.d")
 			srcFiles[i] = cppFile
-			deps = append(deps, genAidl(ctx, srcFile, cppFile, buildFlags.aidlFlags)...)
+			deps = append(deps, genAidl(ctx, aidlRule, srcFile, cppFile, depFile, buildFlags.aidlFlags)...)
 		case ".rs", ".fs":
 			cppFile := rsGeneratedCppFile(ctx, srcFile)
 			rsFiles = append(rsFiles, srcFiles[i])
@@ -236,6 +251,10 @@ func genSources(ctx android.ModuleContext, srcFiles android.Paths,
 		}
 	}
 
+	if aidlRule != nil {
+		aidlRule.Build(pctx, ctx, "aidl", "gen aidl")
+	}
+
 	if yaccRule_ != nil {
 		yaccRule_.Build(pctx, ctx, "yacc", "gen yacc")
 	}
diff --git a/cc/gen_test.go b/cc/gen_test.go
index a0f7308c2..e4219d999 100644
--- a/cc/gen_test.go
+++ b/cc/gen_test.go
@@ -15,6 +15,7 @@
 package cc
 
 import (
+	"path/filepath"
 	"testing"
 )
 
@@ -32,7 +33,7 @@ func TestGen(t *testing.T) {
 		aidl := ctx.ModuleForTests("libfoo", "android_arm_armv7-a-neon_core_shared").Rule("aidl")
 		libfoo := ctx.ModuleForTests("libfoo", "android_arm_armv7-a-neon_core_shared").Module().(*Module)
 
-		if !inList("-I"+aidl.Args["outDir"], libfoo.flags.GlobalFlags) {
+		if !inList("-I"+filepath.Dir(aidl.Output.String()), libfoo.flags.GlobalFlags) {
 			t.Errorf("missing aidl includes in global flags")
 		}
 	})
@@ -55,7 +56,7 @@ func TestGen(t *testing.T) {
 		aidl := ctx.ModuleForTests("libfoo", "android_arm_armv7-a-neon_core_shared").Rule("aidl")
 		libfoo := ctx.ModuleForTests("libfoo", "android_arm_armv7-a-neon_core_shared").Module().(*Module)
 
-		if !inList("-I"+aidl.Args["outDir"], libfoo.flags.GlobalFlags) {
+		if !inList("-I"+filepath.Dir(aidl.Output.String()), libfoo.flags.GlobalFlags) {
 			t.Errorf("missing aidl includes in global flags")
 		}
 	})