main.go

Documentation: cmd/asm

     1  // Copyright 2014 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 main
     6  
     7  import (
     8  	"bufio"
     9  	"flag"
    10  	"fmt"
    11  	"internal/buildcfg"
    12  	"log"
    13  	"os"
    14  
    15  	"cmd/asm/internal/arch"
    16  	"cmd/asm/internal/asm"
    17  	"cmd/asm/internal/flags"
    18  	"cmd/asm/internal/lex"
    19  
    20  	"cmd/internal/bio"
    21  	"cmd/internal/obj"
    22  	"cmd/internal/objabi"
    23  )
    24  
    25  func main() {
    26  	log.SetFlags(0)
    27  	log.SetPrefix("asm: ")
    28  
    29  	buildcfg.Check()
    30  	GOARCH := buildcfg.GOARCH
    31  
    32  	flags.Parse()
    33  
    34  	architecture := arch.Set(GOARCH, *flags.Shared || *flags.Dynlink)
    35  	if architecture == nil {
    36  		log.Fatalf("unrecognized architecture %s", GOARCH)
    37  	}
    38  	ctxt := obj.Linknew(architecture.LinkArch)
    39  	ctxt.Debugasm = flags.PrintOut
    40  	ctxt.Debugvlog = flags.DebugV
    41  	ctxt.Flag_dynlink = *flags.Dynlink
    42  	ctxt.Flag_linkshared = *flags.Linkshared
    43  	ctxt.Flag_shared = *flags.Shared || *flags.Dynlink
    44  	ctxt.Flag_maymorestack = flags.DebugFlags.MayMoreStack
    45  	ctxt.Debugpcln = flags.DebugFlags.PCTab
    46  	ctxt.IsAsm = true
    47  	ctxt.Pkgpath = *flags.Importpath
    48  	switch *flags.Spectre {
    49  	default:
    50  		log.Printf("unknown setting -spectre=%s", *flags.Spectre)
    51  		os.Exit(2)
    52  	case "":
    53  		// nothing
    54  	case "index":
    55  		// known to compiler; ignore here so people can use
    56  		// the same list with -gcflags=-spectre=LIST and -asmflags=-spectrre=LIST
    57  	case "all", "ret":
    58  		ctxt.Retpoline = true
    59  	}
    60  
    61  	ctxt.Bso = bufio.NewWriter(os.Stdout)
    62  	defer ctxt.Bso.Flush()
    63  
    64  	architecture.Init(ctxt)
    65  
    66  	// Create object file, write header.
    67  	buf, err := bio.Create(*flags.OutputFile)
    68  	if err != nil {
    69  		log.Fatal(err)
    70  	}
    71  	defer buf.Close()
    72  
    73  	if !*flags.SymABIs {
    74  		buf.WriteString(objabi.HeaderString())
    75  		fmt.Fprintf(buf, "!\n")
    76  	}
    77  
    78  	// Set macros for GOEXPERIMENTs so we can easily switch
    79  	// runtime assembly code based on them.
    80  	if objabi.LookupPkgSpecial(ctxt.Pkgpath).AllowAsmABI {
    81  		for _, exp := range buildcfg.Experiment.Enabled() {
    82  			flags.D = append(flags.D, "GOEXPERIMENT_"+exp)
    83  		}
    84  	}
    85  
    86  	var ok, diag bool
    87  	var failedFile string
    88  	for _, f := range flag.Args() {
    89  		lexer := lex.NewLexer(f)
    90  		parser := asm.NewParser(ctxt, architecture, lexer)
    91  		ctxt.DiagFunc = func(format string, args ...interface{}) {
    92  			diag = true
    93  			log.Printf(format, args...)
    94  		}
    95  		if *flags.SymABIs {
    96  			ok = parser.ParseSymABIs(buf)
    97  		} else {
    98  			pList := new(obj.Plist)
    99  			pList.Firstpc, ok = parser.Parse()
   100  			// reports errors to parser.Errorf
   101  			if ok {
   102  				obj.Flushplist(ctxt, pList, nil)
   103  			}
   104  		}
   105  		if !ok {
   106  			failedFile = f
   107  			break
   108  		}
   109  	}
   110  	if ok && !*flags.SymABIs {
   111  		ctxt.NumberSyms()
   112  		obj.WriteObjFile(ctxt, buf)
   113  	}
   114  	if !ok || diag {
   115  		if failedFile != "" {
   116  			log.Printf("assembly of %s failed", failedFile)
   117  		} else {
   118  			log.Print("assembly failed")
   119  		}
   120  		buf.Close()
   121  		os.Remove(*flags.OutputFile)
   122  		os.Exit(1)
   123  	}
   124  }
   125
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