sys/syz-sysgen: serialize descriptions as gob and embed

Instead of generating Go files with descriptions
serialize them as gob and compress with flate.

This significantly reduces build time, go vet time,
and solves scalability problems with some static analysis tools.

Reference times (all after rm -rf ~/.cache/go-build) before:

TIME="%e %P %M" time go install ./syz-manager
48.29 577% 4824820

TIME="%e %P %M" time go test -c ./prog
56.28 380% 6973292

After:

TIME="%e %P %M" time go install ./syz-manager
22.81 865% 859788

TIME="%e %P %M" time go test -c ./prog
12.74 565% 267760

syz-manager size before/after: 194712597 -> 83418407
-57% even provided we now embed all descriptions
instead of just a single arch.

Deflate/decoding time for a single Linux arch is ~330ms.

Fixes #5542

3 files changed, 10 insertions, 11 deletions

diff --git a/prog/any.go b/prog/any.go
index c43d8dd8d..cb49f3494 100644
--- a/prog/any.go
+++ b/prog/any.go
@@ -24,7 +24,7 @@ type anyTypes struct {
 
 func (target *Target) initAnyTypes() {
 	var anyPtrs *UnionType
-	for _, typ := range target.types {
+	for _, typ := range target.Types {
 		if typ.Name() == "ANYPTRS" {
 			anyPtrs = typ.(*UnionType)
 			break
diff --git a/prog/target.go b/prog/target.go
index 50fcecdbc..11127046b 100644
--- a/prog/target.go
+++ b/prog/target.go
@@ -30,6 +30,7 @@ type Target struct {
 	Resources []*ResourceDesc
 	Consts    []ConstValue
 	Flags     []FlagDesc
+	Types     []Type
 
 	// MakeDataMmap creates calls that mmaps target data memory range.
 	MakeDataMmap func() []*Call
@@ -70,8 +71,8 @@ type Target struct {
 	FlagsMap   map[string][]string
 
 	init        sync.Once
+	fillArch    func(target *Target)
 	initArch    func(target *Target)
-	types       []Type
 	resourceMap map[string]*ResourceDesc
 	// Maps resource name to a list of calls that can create the resource.
 	resourceCtors map[string][]ResourceCtor
@@ -86,20 +87,17 @@ const maxSpecialPointers = 16
 
 var targets = make(map[string]*Target)
 
-func RegisterTarget(target *Target, types []Type, initArch func(target *Target)) {
+func RegisterTarget(target *Target, fill, init func(target *Target)) {
 	key := target.OS + "/" + target.Arch
 	if targets[key] != nil {
 		panic(fmt.Sprintf("duplicate target %v", key))
 	}
-	target.initArch = initArch
-	target.types = types
+	target.fillArch = fill
+	target.initArch = init
 	targets[key] = target
 }
 
 func GetTarget(OS, arch string) (*Target, error) {
-	if OS == "android" {
-		OS = "linux"
-	}
 	key := OS + "/" + arch
 	target := targets[key]
 	if target == nil {
@@ -132,6 +130,7 @@ func AllTargets() []*Target {
 func (target *Target) lazyInit() {
 	target.Neutralize = func(c *Call, fixStructure bool) error { return nil }
 	target.AnnotateCall = func(c ExecCall) string { return "" }
+	target.fillArch(target)
 	target.initTarget()
 	target.initUselessHints()
 	target.initRelatedFields()
@@ -155,7 +154,7 @@ func (target *Target) lazyInit() {
 		}
 	}
 	// These are used only during lazyInit.
-	target.types = nil
+	target.Types = nil
 }
 
 func (target *Target) initTarget() {
@@ -165,7 +164,7 @@ func (target *Target) initTarget() {
 		target.ConstMap[c.Name] = c.Value
 	}
 
-	target.resourceMap = restoreLinks(target.Syscalls, target.Resources, target.types)
+	target.resourceMap = restoreLinks(target.Syscalls, target.Resources, target.Types)
 	target.initAnyTypes()
 
 	target.SyscallMap = make(map[string]*Syscall)
diff --git a/prog/test/fuzz.go b/prog/test/fuzz.go
index 9b47234b3..98582a818 100644
--- a/prog/test/fuzz.go
+++ b/prog/test/fuzz.go
@@ -9,8 +9,8 @@ import (
 	"math/rand"
 
 	"github.com/google/syzkaller/prog"
+	_ "github.com/google/syzkaller/sys"
 	"github.com/google/syzkaller/sys/targets"
-	_ "github.com/google/syzkaller/sys/test/gen" // import the target we use for fuzzing
 )
 
 func FuzzDeserialize(data []byte) int {