1// Copyright 2015 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// Package flags implements top-level flags and the usage message for the assembler. 6package flags 7 8import ( 9 "cmd/internal/obj" 10 "cmd/internal/objabi" 11 "flag" 12 "fmt" 13 "os" 14 "path/filepath" 15 "strings" 16) 17 18var ( 19 Debug = flag.Bool("debug", false, "dump instructions as they are parsed") 20 OutputFile = flag.String("o", "", "output file; default foo.o for /a/b/c/foo.s as first argument") 21 TrimPath = flag.String("trimpath", "", "remove prefix from recorded source file paths") 22 Shared = flag.Bool("shared", false, "generate code that can be linked into a shared library") 23 Dynlink = flag.Bool("dynlink", false, "support references to Go symbols defined in other shared libraries") 24 Linkshared = flag.Bool("linkshared", false, "generate code that will be linked against Go shared libraries") 25 AllErrors = flag.Bool("e", false, "no limit on number of errors reported") 26 SymABIs = flag.Bool("gensymabis", false, "write symbol ABI information to output file, don't assemble") 27 Importpath = flag.String("p", obj.UnlinkablePkg, "set expected package import to path") 28 Spectre = flag.String("spectre", "", "enable spectre mitigations in `list` (all, ret)") 29) 30 31var DebugFlags struct { 32 MayMoreStack string `help:"call named function before all stack growth checks"` 33 PCTab string `help:"print named pc-value table\nOne of: pctospadj, pctofile, pctoline, pctoinline, pctopcdata"` 34} 35 36var ( 37 D MultiFlag 38 I MultiFlag 39 PrintOut int 40 DebugV bool 41) 42 43func init() { 44 flag.Var(&D, "D", "predefined symbol with optional simple value -D=identifier=value; can be set multiple times") 45 flag.Var(&I, "I", "include directory; can be set multiple times") 46 flag.BoolVar(&DebugV, "v", false, "print debug output") 47 flag.Var(objabi.NewDebugFlag(&DebugFlags, nil), "d", "enable debugging settings; try -d help") 48 objabi.AddVersionFlag() // -V 49 objabi.Flagcount("S", "print assembly and machine code", &PrintOut) 50} 51 52// MultiFlag allows setting a value multiple times to collect a list, as in -I=dir1 -I=dir2. 53type MultiFlag []string 54 55func (m *MultiFlag) String() string { 56 if len(*m) == 0 { 57 return "" 58 } 59 return fmt.Sprint(*m) 60} 61 62func (m *MultiFlag) Set(val string) error { 63 (*m) = append(*m, val) 64 return nil 65} 66 67func Usage() { 68 fmt.Fprintf(os.Stderr, "usage: asm [options] file.s ...\n") 69 fmt.Fprintf(os.Stderr, "Flags:\n") 70 flag.PrintDefaults() 71 os.Exit(2) 72} 73 74func Parse() { 75 objabi.Flagparse(Usage) 76 if flag.NArg() == 0 { 77 flag.Usage() 78 } 79 80 // Flag refinement. 81 if *OutputFile == "" { 82 if flag.NArg() != 1 { 83 flag.Usage() 84 } 85 input := filepath.Base(flag.Arg(0)) 86 input = strings.TrimSuffix(input, ".s") 87 *OutputFile = fmt.Sprintf("%s.o", input) 88 } 89} 90