Makefile: don't compile all targets into target binaries

Currently target binaries contain support for all OS/arch combinations.
However, obviously a fuchsia target binary won't test windows.
For target binaries we need support only for a single target
(with the exception of 386/arm target in amd64/arm64 binaries).
So compile in only _the_ target into target binaries.
This reduces akaros/amd64 fuzzer binary from 33 to 7 MB
and execprog from 28 to 2 MB.

1 files changed, 23 insertions, 20 deletions

diff --git a/Makefile b/Makefile
index bdfe36938..f23eb3214 100644
--- a/Makefile
+++ b/Makefile
@@ -49,11 +49,6 @@ ifeq ("$(TARGETOS)", "fuchsia")
 	GO = "$(SOURCEDIR)/scripts/devshell/go"
 endif
 
-ifeq ("$(TARGETOS)", "akaros")
-	TARGETGOOS := $(HOSTOS)
-	TARGETGOARCH := $(HOSTARCH)
-endif
-
 GITREV=$(shell git rev-parse HEAD)
 ifeq ("$(shell git diff --shortstat)", "")
 	REV=$(GITREV)
@@ -66,8 +61,16 @@ endif
 # 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/sys.GitRevision=$(REV)"
+GOHOSTFLAGS := $(GOFLAGS)
+GOTARGETFLAGS := $(GOFLAGS)
 ifneq ("$(GOTAGS)", "")
-	GOFLAGS += "-tags=$(GOTAGS)"
+	GOHOSTFLAGS += "-tags=$(GOTAGS)"
+endif
+GOTARGETFLAGS += "-tags=syz_target syz_os_$(TARGETOS) syz_arch_$(TARGETVMARCH) $(GOTAGS)"
+
+ifeq ("$(TARGETOS)", "akaros")
+	TARGETGOOS := $(HOSTOS)
+	TARGETGOARCH := $(HOSTARCH)
 endif
 
 .PHONY: all host target \
@@ -103,42 +106,42 @@ executor:
 		-DGOOS_$(TARGETOS)=1 -DGOARCH_$(TARGETARCH)=1  -DGIT_REVISION=\"$(REV)\"
 
 manager:
-	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOFLAGS) -o ./bin/syz-manager github.com/google/syzkaller/syz-manager
+	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOHOSTFLAGS) -o ./bin/syz-manager github.com/google/syzkaller/syz-manager
 
 fuzzer:
-	GOOS=$(TARGETGOOS) GOARCH=$(TARGETGOARCH) $(GO) build $(GOFLAGS) -o ./bin/$(TARGETOS)_$(TARGETVMARCH)/syz-fuzzer$(EXE) github.com/google/syzkaller/syz-fuzzer
+	GOOS=$(TARGETGOOS) GOARCH=$(TARGETGOARCH) $(GO) build $(GOTARGETFLAGS) -o ./bin/$(TARGETOS)_$(TARGETVMARCH)/syz-fuzzer$(EXE) github.com/google/syzkaller/syz-fuzzer
 
 execprog:
-	GOOS=$(TARGETGOOS) GOARCH=$(TARGETGOARCH) $(GO) build $(GOFLAGS) -o ./bin/$(TARGETOS)_$(TARGETVMARCH)/syz-execprog$(EXE) github.com/google/syzkaller/tools/syz-execprog
+	GOOS=$(TARGETGOOS) GOARCH=$(TARGETGOARCH) $(GO) build $(GOTARGETFLAGS) -o ./bin/$(TARGETOS)_$(TARGETVMARCH)/syz-execprog$(EXE) github.com/google/syzkaller/tools/syz-execprog
 
 ci:
-	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOFLAGS) -o ./bin/syz-ci github.com/google/syzkaller/syz-ci
+	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOHOSTFLAGS) -o ./bin/syz-ci github.com/google/syzkaller/syz-ci
 
 hub:
-	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOFLAGS) -o ./bin/syz-hub github.com/google/syzkaller/syz-hub
+	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOHOSTFLAGS) -o ./bin/syz-hub github.com/google/syzkaller/syz-hub
 
 repro:
-	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOFLAGS) -o ./bin/syz-repro github.com/google/syzkaller/tools/syz-repro
+	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOHOSTFLAGS) -o ./bin/syz-repro github.com/google/syzkaller/tools/syz-repro
 
 mutate:
-	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOFLAGS) -o ./bin/syz-mutate github.com/google/syzkaller/tools/syz-mutate
+	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOHOSTFLAGS) -o ./bin/syz-mutate github.com/google/syzkaller/tools/syz-mutate
 
 prog2c:
-	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOFLAGS) -o ./bin/syz-prog2c github.com/google/syzkaller/tools/syz-prog2c
+	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOHOSTFLAGS) -o ./bin/syz-prog2c github.com/google/syzkaller/tools/syz-prog2c
 
 stress:
-	GOOS=$(TARGETGOOS) GOARCH=$(TARGETGOARCH) $(GO) build $(GOFLAGS) -o ./bin/$(TARGETOS)_$(TARGETVMARCH)/syz-stress$(EXE) github.com/google/syzkaller/tools/syz-stress
+	GOOS=$(TARGETGOOS) GOARCH=$(TARGETGOARCH) $(GO) build $(GOTARGETFLAGS) -o ./bin/$(TARGETOS)_$(TARGETVMARCH)/syz-stress$(EXE) github.com/google/syzkaller/tools/syz-stress
 
 db:
-	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOFLAGS) -o ./bin/syz-db github.com/google/syzkaller/tools/syz-db
+	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOHOSTFLAGS) -o ./bin/syz-db github.com/google/syzkaller/tools/syz-db
 
 upgrade:
-	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOFLAGS) -o ./bin/syz-upgrade github.com/google/syzkaller/tools/syz-upgrade
+	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOHOSTFLAGS) -o ./bin/syz-upgrade github.com/google/syzkaller/tools/syz-upgrade
 
 extract: bin/syz-extract
 	bin/syz-extract -build -os=$(TARGETOS) -sourcedir=$(SOURCEDIR) $(FILES)
 bin/syz-extract:
-	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOFLAGS) -o $@ ./sys/syz-extract
+	GOOS=$(HOSTOS) GOARCH=$(HOSTARCH) $(HOSTGO) build $(GOHOSTFLAGS) -o $@ ./sys/syz-extract
 
 generate: generate_go generate_sys
 	$(MAKE) format
@@ -150,7 +153,7 @@ generate_sys: bin/syz-sysgen
 	bin/syz-sysgen
 
 bin/syz-sysgen:
-	$(GO) build $(GOFLAGS) -o $@ ./sys/syz-sysgen
+	$(GO) build $(GOHOSTFLAGS) -o $@ ./sys/syz-sysgen
 
 format: format_go format_cpp format_sys
 
@@ -170,7 +173,7 @@ format_sys: bin/syz-fmt
 	bin/syz-fmt sys/windows
 
 bin/syz-fmt:
-	$(GO) build $(GOFLAGS) -o $@ ./tools/syz-fmt
+	$(GO) build $(GOHOSTFLAGS) -o $@ ./tools/syz-fmt
 
 tidy:
 	# A single check is enabled for now. But it's always fixable and proved to be useful.