Makefile, sys/targets: move all native compilation logic to sys/targets

We currently have native cross-compilation logic duplicated
in Makefile and in sys/targets. Some pieces are missed in one
place, some are in another. Only pkg/csource knows how to check
for -static support.

Move all CC/CFLAGS logic to sys/targets and pull results in Makefile.

This should make Makefile work on distros that have broken x86_64-linux-gnu-gcc,
now we will use just gcc. And this removes the need to define NOSTATIC,
as it's always auto-detected.

This also paves the way for making pkg/csource work on OSes other than Linux.

1 files changed, 52 insertions, 0 deletions

diff --git a/tools/syz-env/env.go b/tools/syz-env/env.go
new file mode 100644
index 000000000..775f05ca2
--- /dev/null
+++ b/tools/syz-env/env.go
@@ -0,0 +1,52 @@
+// Copyright 2018 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+	"strconv"
+	"strings"
+
+	"github.com/google/syzkaller/sys/targets"
+)
+
+func main() {
+	hostOS := or(os.Getenv("HOSTOS"), runtime.GOOS)
+	hostArch := or(os.Getenv("HOSTARCH"), runtime.GOARCH)
+	targetOS := or(os.Getenv("TARGETOS"), hostOS)
+	targetArch := or(os.Getenv("TARGETARCH"), hostArch)
+	targetVMArch := or(os.Getenv("TARGETVMARCH"), targetArch)
+	target := targets.Get(targetOS, targetArch)
+	if target == nil {
+		fmt.Printf("unknown target %v/%v\n", targetOS, targetArch)
+		os.Exit(1)
+	}
+	type Var struct {
+		Name string
+		Val  string
+	}
+	vars := []Var{
+		{"HOSTOS", hostOS},
+		{"HOSTARCH", hostArch},
+		{"TARGETOS", targetOS},
+		{"TARGETARCH", targetArch},
+		{"TARGETVMARCH", targetVMArch},
+		{"CC", target.CCompiler},
+		{"ADDCFLAGS", strings.Join(target.CrossCFlags, " ")},
+		{"NCORES", strconv.Itoa(runtime.NumCPU())},
+		{"EXE", target.ExeExtension},
+	}
+	for _, v := range vars {
+		fmt.Printf("export %v=%v\\n", v.Name, v.Val)
+	}
+}
+
+func or(s1, s2 string) string {
+	if s1 != "" {
+		return s1
+	}
+	return s2
+}