Make it possible to debug soong_ui.

This works by setting the SOONG_UI_DELVE= environment variable to the
port on which soong_ui should accept a Delve connection on.

This is achieved by reusing the Delve execution logic between soong_ui
and soong_build.

Test: Manual.
Change-Id: Id2c1d4b6faac1a4a3918c91030ce2239f7daf54f

android/env.go

@@ -15,11 +15,6 @@
 package android
 
 import (
-	"fmt"
-	"os"
-	"strings"
-	"syscall"
-
 	"android/soong/shared"
 )
 
@@ -31,9 +26,6 @@ import (
 // a manifest regeneration.
 
 var originalEnv map[string]string
-var soongDelveListen string
-var soongDelvePath string
-var isDebugging bool
 
 func InitEnvironment(envFile string) {
 	var err error
@@ -41,51 +33,6 @@ func InitEnvironment(envFile string) {
 	if err != nil {
 		panic(err)
 	}
-
-	soongDelveListen = originalEnv["SOONG_DELVE"]
-	soongDelvePath = originalEnv["SOONG_DELVE_PATH"]
-}
-
-// Returns whether the current process is running under Delve due to
-// ReexecWithDelveMaybe().
-func IsDebugging() bool {
-	return isDebugging
-}
-func ReexecWithDelveMaybe() {
-	isDebugging = os.Getenv("SOONG_DELVE_REEXECUTED") == "true"
-	if isDebugging || soongDelveListen == "" {
-		return
-	}
-
-	if soongDelvePath == "" {
-		fmt.Fprintln(os.Stderr, "SOONG_DELVE is set but failed to find dlv")
-		os.Exit(1)
-	}
-
-	soongDelveEnv := []string{}
-	for _, env := range os.Environ() {
-		idx := strings.IndexRune(env, '=')
-		if idx != -1 {
-			soongDelveEnv = append(soongDelveEnv, env)
-		}
-	}
-
-	soongDelveEnv = append(soongDelveEnv, "SOONG_DELVE_REEXECUTED=true")
-
-	dlvArgv := []string{
-		soongDelvePath,
-		"--listen=:" + soongDelveListen,
-		"--headless=true",
-		"--api-version=2",
-		"exec",
-		os.Args[0],
-		"--",
-	}
-	dlvArgv = append(dlvArgv, os.Args[1:]...)
-	os.Chdir(absSrcDir)
-	syscall.Exec(soongDelvePath, dlvArgv, soongDelveEnv)
-	fmt.Fprintln(os.Stderr, "exec() failed while trying to reexec with Delve")
-	os.Exit(1)
 }
 
 func EnvSingleton() Singleton {

android/writedocs.go

@@ -66,7 +66,9 @@ func (c *docsSingleton) GenerateBuildActions(ctx SingletonContext) {
 	soongDocs := ctx.Rule(pctx, "soongDocs",
 		blueprint.RuleParams{
 			Command: fmt.Sprintf("rm -f ${outDir}/* && %s --soong_docs %s %s",
-				primaryBuilder.String(), docsFile.String(), strings.Join(os.Args[1:], " ")),
+				primaryBuilder.String(),
+				docsFile.String(),
+				"\""+strings.Join(os.Args[1:], "\" \"")+"\""),
 			CommandDeps: []string{primaryBuilder.String()},
 			Description: fmt.Sprintf("%s docs $out", primaryBuilder.Base()),
 		},

cmd/soong_build/main.go

@@ -33,11 +33,15 @@ var (
 	outDir            string
 	docFile           string
 	bazelQueryViewDir string
+	delveListen       string
+	delvePath         string
 )
 
 func init() {
 	flag.StringVar(&topDir, "top", "", "Top directory of the Android source tree")
 	flag.StringVar(&outDir, "out", "", "Soong output directory (usually $TOP/out/soong)")
+	flag.StringVar(&delveListen, "delve_listen", "", "Delve port to listen on for debugging")
+	flag.StringVar(&delvePath, "delve_path", "", "Path to Delve. Only used if --delve_listen is set")
 	flag.StringVar(&docFile, "soong_docs", "", "build documentation file to output")
 	flag.StringVar(&bazelQueryViewDir, "bazel_queryview_dir", "", "path to the bazel queryview directory")
 }
@@ -87,9 +91,9 @@ func newConfig(srcDir string) android.Config {
 func main() {
 	flag.Parse()
 
+	shared.ReexecWithDelveMaybe(delveListen, delvePath)
 	android.InitSandbox(topDir)
 	android.InitEnvironment(shared.JoinPath(topDir, outDir, "soong.environment.available"))
-	android.ReexecWithDelveMaybe()
 
 	// The top-level Blueprints file is passed as the first argument.
 	srcDir := filepath.Dir(flag.Arg(0))
@@ -101,9 +105,7 @@ func main() {
 	// user sets SOONG_DELVE the first time.
 	configuration.Getenv("SOONG_DELVE")
 	configuration.Getenv("SOONG_DELVE_PATH")
-	// Read the SOONG_DELVE again through configuration so that there is a dependency on the environment variable
-	// and soong_build will rerun when it is set for the first time.
-	if listen := configuration.Getenv("SOONG_DELVE"); listen != "" {
+	if shared.IsDebugging() {
 		// Add a non-existent file to the dependencies so that soong_build will rerun when the debugger is
 		// enabled even if it completed successfully.
 		extraNinjaDeps = append(extraNinjaDeps, filepath.Join(configuration.BuildDir(), "always_rerun_for_delve"))

cmd/soong_ui/main.go

@@ -25,6 +25,7 @@ import (
 	"strings"
 	"time"
 
+	"android/soong/shared"
 	"android/soong/ui/build"
 	"android/soong/ui/logger"
 	"android/soong/ui/metrics"
@@ -118,6 +119,8 @@ func inList(s string, list []string) bool {
 // Command is the type of soong_ui execution. Only one type of
 // execution is specified. The args are specific to the command.
 func main() {
+	shared.ReexecWithDelveMaybe(os.Getenv("SOONG_UI_DELVE"), shared.ResolveDelveBinary())
+
 	buildStarted := time.Now()
 
 	c, args, err := getCommand(os.Args)

shared/debug.go

@@ -1,8 +1,15 @@
 package shared
 
 import (
+	"fmt"
 	"os"
 	"os/exec"
+	"strings"
+	"syscall"
+)
+
+var (
+	isDebugging bool
 )
 
 // Finds the Delve binary to use. Either uses the SOONG_DELVE_PATH environment
@@ -15,3 +22,48 @@ func ResolveDelveBinary() string {
 
 	return result
 }
+
+// Returns whether the current process is running under Delve due to
+// ReexecWithDelveMaybe().
+func IsDebugging() bool {
+	return isDebugging
+}
+
+// Re-executes the binary in question under the control of Delve when
+// delveListen is not the empty string. delvePath gives the path to the Delve.
+func ReexecWithDelveMaybe(delveListen, delvePath string) {
+	isDebugging = os.Getenv("SOONG_DELVE_REEXECUTED") == "true"
+	if isDebugging || delveListen == "" {
+		return
+	}
+
+	if delvePath == "" {
+		fmt.Fprintln(os.Stderr, "Delve debugging requested but failed to find dlv")
+		os.Exit(1)
+	}
+
+	soongDelveEnv := []string{}
+	for _, env := range os.Environ() {
+		idx := strings.IndexRune(env, '=')
+		if idx != -1 {
+			soongDelveEnv = append(soongDelveEnv, env)
+		}
+	}
+
+	soongDelveEnv = append(soongDelveEnv, "SOONG_DELVE_REEXECUTED=true")
+
+	dlvArgv := []string{
+		delvePath,
+		"--listen=:" + delveListen,
+		"--headless=true",
+		"--api-version=2",
+		"exec",
+		os.Args[0],
+		"--",
+	}
+
+	dlvArgv = append(dlvArgv, os.Args[1:]...)
+	syscall.Exec(delvePath, dlvArgv, soongDelveEnv)
+	fmt.Fprintln(os.Stderr, "exec() failed while trying to reexec with Delve")
+	os.Exit(1)
+}

ui/build/soong.go

@@ -105,11 +105,6 @@ func runSoong(ctx Context, config Config) {
 	soongBuildEnv.Set("BAZEL_WORKSPACE", absPath(ctx, "."))
 	soongBuildEnv.Set("BAZEL_METRICS_DIR", config.BazelMetricsDir())
 
-	if os.Getenv("SOONG_DELVE") != "" {
-		// SOONG_DELVE is already in cmd.Environment
-		soongBuildEnv.Set("SOONG_DELVE_PATH", shared.ResolveDelveBinary())
-	}
-
 	err := writeEnvironmentFile(ctx, envFile, soongBuildEnv.AsMap())
 	if err != nil {
 		ctx.Fatalf("failed to write environment file %s: %s", envFile, err)
@@ -176,6 +171,11 @@ func runSoong(ctx Context, config Config) {
 			"-f", filepath.Join(config.SoongOutDir(), file))
 
 		cmd.Environment.Set("SOONG_OUTDIR", config.SoongOutDir())
+		if os.Getenv("SOONG_DELVE") != "" {
+			// SOONG_DELVE is already in cmd.Environment
+			cmd.Environment.Set("SOONG_DELVE_PATH", shared.ResolveDelveBinary())
+		}
+
 		cmd.Sandbox = soongSandbox
 		cmd.RunAndStreamOrFatal()
 	}