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

1 files changed, 3 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index 95eb15ba0..07716b436 100644
--- a/Makefile
+++ b/Makefile
@@ -74,13 +74,12 @@ GITREVDATE=$(shell git log -n 1 --format="%cd" --date=format:%Y%m%d-%H%M%S)
 # That's only needed if you use gdb or nm.
 # If you need that, build manually without these flags.
 GOFLAGS := "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=$(REV) -X 'github.com/google/syzkaller/prog.gitRevisionDate=$(GITREVDATE)'"
+ifneq ("$(GOTAGS)", "")
+	GOFLAGS += " -tags=$(GOTAGS)"
+endif
 
 GOHOSTFLAGS ?= $(GOFLAGS)
 GOTARGETFLAGS ?= $(GOFLAGS)
-ifneq ("$(GOTAGS)", "")
-	GOHOSTFLAGS += "-tags=$(GOTAGS)"
-endif
-GOTARGETFLAGS += "-tags=syz_target syz_os_$(TARGETOS) syz_arch_$(TARGETVMARCH) $(GOTAGS)"
 
 ifeq ("$(TARGETOS)", "test")
 	TARGETGOOS := $(HOSTOS)
@@ -149,7 +148,6 @@ descriptions:
 
 .descriptions: sys/*/*.txt sys/*/*.const bin/syz-sysgen
 	bin/syz-sysgen
-	$(GO) fmt ./sys/... >/dev/null
 	touch .descriptions
 
 manager: descriptions