1 files changed, 64 insertions, 0 deletions
diff --git a/libgo/go/syscall/mkasm.go b/libgo/go/syscall/mkasm.go
new file mode 100644
index 00000000000..2ebaf8d3513
--- /dev/null
+++ b/libgo/go/syscall/mkasm.go
@@ -0,0 +1,64 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore
+
+// mkasm.go generates assembly trampolines to call library routines from Go.
+// This program must be run after mksyscall.pl.
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+func main() {
+	if len(os.Args) != 3 {
+		log.Fatalf("Usage: %s <goos> <arch>", os.Args[0])
+	}
+	goos, arch := os.Args[1], os.Args[2]
+
+	syscallFilename := fmt.Sprintf("syscall_%s.go", goos)
+	syscallArchFilename := fmt.Sprintf("syscall_%s_%s.go", goos, arch)
+
+	in1, err := os.ReadFile(syscallFilename)
+	if err != nil {
+		log.Fatalf("can't open syscall file: %s", err)
+	}
+	in2, err := os.ReadFile(syscallArchFilename)
+	if err != nil {
+		log.Fatalf("can't open syscall file: %s", err)
+	}
+	in3, err := os.ReadFile("z" + syscallArchFilename)
+	if err != nil {
+		log.Fatalf("can't open syscall file: %s", err)
+	}
+	in := string(in1) + string(in2) + string(in3)
+
+	trampolines := map[string]bool{}
+
+	var out bytes.Buffer
+
+	fmt.Fprintf(&out, "// go run mkasm.go %s\n", strings.Join(os.Args[1:], " "))
+	fmt.Fprintf(&out, "// Code generated by the command above; DO NOT EDIT.\n")
+	fmt.Fprintf(&out, "#include \"textflag.h\"\n")
+	for _, line := range strings.Split(in, "\n") {
+		if !strings.HasPrefix(line, "func ") || !strings.HasSuffix(line, "_trampoline()") {
+			continue
+		}
+		fn := line[5 : len(line)-13]
+		if !trampolines[fn] {
+			trampolines[fn] = true
+			fmt.Fprintf(&out, "TEXT ·%s_trampoline(SB),NOSPLIT,$0-0\n", fn)
+			fmt.Fprintf(&out, "\tJMP\t%s(SB)\n", fn)
+		}
+	}
+	err = os.WriteFile(fmt.Sprintf("zsyscall_%s_%s.s", goos, arch), out.Bytes(), 0644)
+	if err != nil {
+		log.Fatalf("can't write syscall file: %s", err)
+	}
+}