Source file src/syscall/mkasm_darwin.go

     1	// Copyright 2018 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	// +build ignore
     6	
     7	// mkasm_darwin.go generates assembly trampolines to call libSystem routines from Go.
     8	//This program must be run after mksyscall.pl.
     9	package main
    10	
    11	import (
    12		"bytes"
    13		"fmt"
    14		"io/ioutil"
    15		"log"
    16		"os"
    17		"strings"
    18	)
    19	
    20	func main() {
    21		in1, err := ioutil.ReadFile("syscall_darwin.go")
    22		if err != nil {
    23			log.Fatalf("can't open syscall_darwin.go: %s", err)
    24		}
    25		arch := os.Args[1]
    26		in2, err := ioutil.ReadFile(fmt.Sprintf("syscall_darwin_%s.go", arch))
    27		if err != nil {
    28			log.Fatalf("can't open syscall_darwin_%s.go: %s", arch, err)
    29		}
    30		in3, err := ioutil.ReadFile(fmt.Sprintf("zsyscall_darwin_%s.go", arch))
    31		if err != nil {
    32			log.Fatalf("can't open zsyscall_darwin_%s.go: %s", arch, err)
    33		}
    34		in := string(in1) + string(in2) + string(in3)
    35	
    36		trampolines := map[string]bool{}
    37	
    38		var out bytes.Buffer
    39	
    40		fmt.Fprintf(&out, "// go run mkasm_darwin.go %s\n", strings.Join(os.Args[1:], " "))
    41		fmt.Fprintf(&out, "// Code generated by the command above; DO NOT EDIT.\n")
    42		fmt.Fprintf(&out, "#include \"textflag.h\"\n")
    43		for _, line := range strings.Split(in, "\n") {
    44			if !strings.HasPrefix(line, "func ") || !strings.HasSuffix(line, "_trampoline()") {
    45				continue
    46			}
    47			fn := line[5 : len(line)-13]
    48			if !trampolines[fn] {
    49				trampolines[fn] = true
    50				fmt.Fprintf(&out, "TEXT ·%s_trampoline(SB),NOSPLIT,$0-0\n", fn)
    51				fmt.Fprintf(&out, "\tJMP\t%s(SB)\n", fn)
    52			}
    53		}
    54		err = ioutil.WriteFile(fmt.Sprintf("zsyscall_darwin_%s.s", arch), out.Bytes(), 0644)
    55		if err != nil {
    56			log.Fatalf("can't write zsyscall_darwin_%s.s: %s", arch, err)
    57		}
    58	}
    59	

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