Add support for packaging rust fuzzers

Test: make haiku-rust
Change-Id: Idd4d836d11e0ae615b59c6648d49348449589787
diff --git a/rust/fuzz.go b/rust/fuzz.go
index d699971..7e1c55a 100644
--- a/rust/fuzz.go
+++ b/rust/fuzz.go
@@ -15,6 +15,10 @@
 package rust
 
 import (
+	"path/filepath"
+	"sort"
+	"strings"
+
 	"android/soong/android"
 	"android/soong/cc"
 	"android/soong/rust/config"
@@ -22,6 +26,7 @@
 
 func init() {
 	android.RegisterModuleType("rust_fuzz", RustFuzzFactory)
+	android.RegisterSingletonType("rust_fuzz_packaging", rustFuzzPackagingFactory)
 }
 
 type fuzzDecorator struct {
@@ -93,3 +98,204 @@
 func (fuzzer *fuzzDecorator) autoDep(ctx android.BottomUpMutatorContext) autoDep {
 	return rlibAutoDep
 }
+
+// Responsible for generating GNU Make rules that package fuzz targets into
+// their architecture & target/host specific zip file.
+type rustFuzzPackager struct {
+	packages    android.Paths
+	fuzzTargets map[string]bool
+}
+
+func rustFuzzPackagingFactory() android.Singleton {
+	return &rustFuzzPackager{}
+}
+
+type fileToZip struct {
+	SourceFilePath        android.Path
+	DestinationPathPrefix string
+}
+
+type archOs struct {
+	hostOrTarget string
+	arch         string
+	dir          string
+}
+
+func (s *rustFuzzPackager) GenerateBuildActions(ctx android.SingletonContext) {
+
+	// Map between each architecture + host/device combination.
+	archDirs := make(map[archOs][]fileToZip)
+
+	// List of individual fuzz targets.
+	s.fuzzTargets = make(map[string]bool)
+
+	ctx.VisitAllModules(func(module android.Module) {
+		// Discard non-fuzz targets.
+		rustModule, ok := module.(*Module)
+		if !ok {
+			return
+		}
+
+		fuzzModule, ok := rustModule.compiler.(*fuzzDecorator)
+		if !ok {
+			return
+		}
+
+		// Discard ramdisk + vendor_ramdisk + recovery modules, they're duplicates of
+		// fuzz targets we're going to package anyway.
+		if !rustModule.Enabled() || rustModule.Properties.PreventInstall ||
+			rustModule.InRamdisk() || rustModule.InVendorRamdisk() || rustModule.InRecovery() {
+			return
+		}
+
+		// Discard modules that are in an unavailable namespace.
+		if !rustModule.ExportedToMake() {
+			return
+		}
+
+		hostOrTargetString := "target"
+		if rustModule.Host() {
+			hostOrTargetString = "host"
+		}
+
+		archString := rustModule.Arch().ArchType.String()
+		archDir := android.PathForIntermediates(ctx, "fuzz", hostOrTargetString, archString)
+		archOs := archOs{hostOrTarget: hostOrTargetString, arch: archString, dir: archDir.String()}
+
+		var files []fileToZip
+		builder := android.NewRuleBuilder(pctx, ctx)
+
+		// Package the corpora into a zipfile.
+		if fuzzModule.corpus != nil {
+			corpusZip := archDir.Join(ctx, module.Name()+"_seed_corpus.zip")
+			command := builder.Command().BuiltTool("soong_zip").
+				Flag("-j").
+				FlagWithOutput("-o ", corpusZip)
+			rspFile := corpusZip.ReplaceExtension(ctx, "rsp")
+			command.FlagWithRspFileInputList("-r ", rspFile, fuzzModule.corpus)
+			files = append(files, fileToZip{corpusZip, ""})
+		}
+
+		// Package the data into a zipfile.
+		if fuzzModule.data != nil {
+			dataZip := archDir.Join(ctx, module.Name()+"_data.zip")
+			command := builder.Command().BuiltTool("soong_zip").
+				FlagWithOutput("-o ", dataZip)
+			for _, f := range fuzzModule.data {
+				intermediateDir := strings.TrimSuffix(f.String(), f.Rel())
+				command.FlagWithArg("-C ", intermediateDir)
+				command.FlagWithInput("-f ", f)
+			}
+			files = append(files, fileToZip{dataZip, ""})
+		}
+
+		// The executable.
+		files = append(files, fileToZip{rustModule.unstrippedOutputFile.Path(), ""})
+
+		// The dictionary.
+		if fuzzModule.dictionary != nil {
+			files = append(files, fileToZip{fuzzModule.dictionary, ""})
+		}
+
+		// Additional fuzz config.
+		if fuzzModule.config != nil {
+			files = append(files, fileToZip{fuzzModule.config, ""})
+		}
+
+		fuzzZip := archDir.Join(ctx, module.Name()+".zip")
+
+		command := builder.Command().BuiltTool("soong_zip").
+			Flag("-j").
+			FlagWithOutput("-o ", fuzzZip)
+
+		for _, file := range files {
+			if file.DestinationPathPrefix != "" {
+				command.FlagWithArg("-P ", file.DestinationPathPrefix)
+			} else {
+				command.Flag("-P ''")
+			}
+			command.FlagWithInput("-f ", file.SourceFilePath)
+		}
+
+		builder.Build("create-"+fuzzZip.String(),
+			"Package "+module.Name()+" for "+archString+"-"+hostOrTargetString)
+
+		// Don't add modules to 'make haiku-rust' that are set to not be
+		// exported to the fuzzing infrastructure.
+		if config := fuzzModule.Properties.Fuzz_config; config != nil {
+			if rustModule.Host() && !BoolDefault(config.Fuzz_on_haiku_host, true) {
+				return
+			} else if !BoolDefault(config.Fuzz_on_haiku_device, true) {
+				return
+			}
+		}
+
+		s.fuzzTargets[module.Name()] = true
+		archDirs[archOs] = append(archDirs[archOs], fileToZip{fuzzZip, ""})
+	})
+
+	var archOsList []archOs
+	for archOs := range archDirs {
+		archOsList = append(archOsList, archOs)
+	}
+	sort.Slice(archOsList, func(i, j int) bool { return archOsList[i].dir < archOsList[j].dir })
+
+	for _, archOs := range archOsList {
+		filesToZip := archDirs[archOs]
+		arch := archOs.arch
+		hostOrTarget := archOs.hostOrTarget
+		builder := android.NewRuleBuilder(pctx, ctx)
+		outputFile := android.PathForOutput(ctx, "fuzz-rust-"+hostOrTarget+"-"+arch+".zip")
+		s.packages = append(s.packages, outputFile)
+
+		command := builder.Command().BuiltTool("soong_zip").
+			Flag("-j").
+			FlagWithOutput("-o ", outputFile).
+			Flag("-L 0") // No need to try and re-compress the zipfiles.
+
+		for _, fileToZip := range filesToZip {
+			if fileToZip.DestinationPathPrefix != "" {
+				command.FlagWithArg("-P ", fileToZip.DestinationPathPrefix)
+			} else {
+				command.Flag("-P ''")
+			}
+			command.FlagWithInput("-f ", fileToZip.SourceFilePath)
+		}
+		builder.Build("create-fuzz-package-"+arch+"-"+hostOrTarget,
+			"Create fuzz target packages for "+arch+"-"+hostOrTarget)
+	}
+
+}
+
+func (s *rustFuzzPackager) MakeVars(ctx android.MakeVarsContext) {
+	packages := s.packages.Strings()
+	sort.Strings(packages)
+
+	ctx.Strict("SOONG_RUST_FUZZ_PACKAGING_ARCH_MODULES", strings.Join(packages, " "))
+
+	// Preallocate the slice of fuzz targets to minimise memory allocations.
+	fuzzTargets := make([]string, 0, len(s.fuzzTargets))
+	for target, _ := range s.fuzzTargets {
+		fuzzTargets = append(fuzzTargets, target)
+	}
+	sort.Strings(fuzzTargets)
+	ctx.Strict("ALL_RUST_FUZZ_TARGETS", strings.Join(fuzzTargets, " "))
+}
+
+func (fuzz *fuzzDecorator) install(ctx ModuleContext) {
+	fuzz.binaryDecorator.baseCompiler.dir = filepath.Join(
+		"fuzz", ctx.Target().Arch.ArchType.String(), ctx.ModuleName())
+	fuzz.binaryDecorator.baseCompiler.dir64 = filepath.Join(
+		"fuzz", ctx.Target().Arch.ArchType.String(), ctx.ModuleName())
+	fuzz.binaryDecorator.baseCompiler.install(ctx)
+
+	if fuzz.Properties.Corpus != nil {
+		fuzz.corpus = android.PathsForModuleSrc(ctx, fuzz.Properties.Corpus)
+	}
+	if fuzz.Properties.Data != nil {
+		fuzz.data = android.PathsForModuleSrc(ctx, fuzz.Properties.Data)
+	}
+	if fuzz.Properties.Dictionary != nil {
+		fuzz.dictionary = android.PathForModuleSrc(ctx, *fuzz.Properties.Dictionary)
+	}
+}