Add build-flag-declarations tool

This will be used to gather build flag declarations

Bug: 328495189
Test: manual, TH
Ignore-AOSP-First: cherry-pick
Merged-In: I155c26b1442347c4d433c9cbf22b94d944636702
Change-Id: I155c26b1442347c4d433c9cbf22b94d944636702

cmd/release_config/build_flag_declarations/main.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	rc_lib "android/soong/cmd/release_config/release_config_lib"
+)
+
+type Flags struct {
+	// The path to the top of the workspace.  Default: ".".
+	top string
+
+	// Output file.
+	output string
+
+	// Format for output file
+	format string
+
+	// List of flag_declaration files to add.
+	decls rc_lib.StringList
+
+	// List of flag_artifacts files to merge.
+	intermediates rc_lib.StringList
+
+	// Disable warning messages
+	quiet bool
+
+	// Panic on errors.
+	debug bool
+}
+
+func main() {
+	var flags Flags
+	topDir, err := rc_lib.GetTopDir()
+
+	// Handle the common arguments
+	flag.StringVar(&flags.top, "top", topDir, "path to top of workspace")
+	flag.Var(&flags.decls, "decl", "path to a flag_declaration file. May be repeated")
+	flag.Var(&flags.intermediates, "intermediate", "path to a flag_artifacts file (output from a prior run). May be repeated")
+	flag.StringVar(&flags.format, "format", "pb", "output file format")
+	flag.StringVar(&flags.output, "output", "build_flags.pb", "output file")
+	flag.BoolVar(&flags.debug, "debug", false, "turn on debugging output for errors")
+	flag.BoolVar(&flags.quiet, "quiet", false, "disable warning messages")
+	flag.Parse()
+
+	errorExit := func(err error) {
+		if flags.debug {
+			panic(err)
+		}
+		fmt.Fprintf(os.Stderr, "%s\n", err)
+		os.Exit(1)
+	}
+
+	if flags.quiet {
+		rc_lib.DisableWarnings()
+	}
+
+	if err = os.Chdir(flags.top); err != nil {
+		errorExit(err)
+	}
+
+	flagArtifacts := rc_lib.FlagArtifactsFactory("")
+	for _, intermediate := range flags.intermediates {
+		fas := rc_lib.FlagArtifactsFactory(intermediate)
+		for _, fa := range *fas {
+			(*flagArtifacts)[*fa.FlagDeclaration.Name] = fa
+		}
+	}
+	for _, decl := range flags.decls {
+		fa := rc_lib.FlagArtifactFactory(decl)
+		(*flagArtifacts)[*fa.FlagDeclaration.Name] = fa
+	}
+
+	message := flagArtifacts.GenerateFlagArtifacts()
+	err = rc_lib.WriteFormattedMessage(flags.output, flags.format, message)
+	if err != nil {
+		errorExit(err)
+	}
+}