1 files changed, 89 insertions, 0 deletions
diff --git a/src/cmd/asm/internal/flags/flags.go b/src/cmd/asm/internal/flags/flags.go
new file mode 100644
index 0000000..e15a062
--- /dev/null
+++ b/src/cmd/asm/internal/flags/flags.go
@@ -0,0 +1,89 @@
+// Copyright 2015 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.
+
+// Package flags implements top-level flags and the usage message for the assembler.
+package flags
+
+import (
+	"cmd/internal/obj"
+	"cmd/internal/objabi"
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var (
+	Debug      = flag.Bool("debug", false, "dump instructions as they are parsed")
+	OutputFile = flag.String("o", "", "output file; default foo.o for /a/b/c/foo.s as first argument")
+	TrimPath   = flag.String("trimpath", "", "remove prefix from recorded source file paths")
+	Shared     = flag.Bool("shared", false, "generate code that can be linked into a shared library")
+	Dynlink    = flag.Bool("dynlink", false, "support references to Go symbols defined in other shared libraries")
+	Linkshared = flag.Bool("linkshared", false, "generate code that will be linked against Go shared libraries")
+	AllErrors  = flag.Bool("e", false, "no limit on number of errors reported")
+	SymABIs    = flag.Bool("gensymabis", false, "write symbol ABI information to output file, don't assemble")
+	Importpath = flag.String("p", obj.UnlinkablePkg, "set expected package import to path")
+	Spectre    = flag.String("spectre", "", "enable spectre mitigations in `list` (all, ret)")
+)
+
+var DebugFlags struct {
+	MayMoreStack string `help:"call named function before all stack growth checks"`
+	PCTab        string `help:"print named pc-value table\nOne of: pctospadj, pctofile, pctoline, pctoinline, pctopcdata"`
+}
+
+var (
+	D        MultiFlag
+	I        MultiFlag
+	PrintOut int
+	DebugV   bool
+)
+
+func init() {
+	flag.Var(&D, "D", "predefined symbol with optional simple value -D=identifier=value; can be set multiple times")
+	flag.Var(&I, "I", "include directory; can be set multiple times")
+	flag.BoolVar(&DebugV, "v", false, "print debug output")
+	flag.Var(objabi.NewDebugFlag(&DebugFlags, nil), "d", "enable debugging settings; try -d help")
+	objabi.AddVersionFlag() // -V
+	objabi.Flagcount("S", "print assembly and machine code", &PrintOut)
+}
+
+// MultiFlag allows setting a value multiple times to collect a list, as in -I=dir1 -I=dir2.
+type MultiFlag []string
+
+func (m *MultiFlag) String() string {
+	if len(*m) == 0 {
+		return ""
+	}
+	return fmt.Sprint(*m)
+}
+
+func (m *MultiFlag) Set(val string) error {
+	(*m) = append(*m, val)
+	return nil
+}
+
+func Usage() {
+	fmt.Fprintf(os.Stderr, "usage: asm [options] file.s ...\n")
+	fmt.Fprintf(os.Stderr, "Flags:\n")
+	flag.PrintDefaults()
+	os.Exit(2)
+}
+
+func Parse() {
+	objabi.Flagparse(Usage)
+	if flag.NArg() == 0 {
+		flag.Usage()
+	}
+
+	// Flag refinement.
+	if *OutputFile == "" {
+		if flag.NArg() != 1 {
+			flag.Usage()
+		}
+		input := filepath.Base(flag.Arg(0))
+		input = strings.TrimSuffix(input, ".s")
+		*OutputFile = fmt.Sprintf("%s.o", input)
+	}
+}