code review 48870044: cmd/link: intial skeleton of linker written in Go

src/cmd/link/prog.go

 // Copyright 2014 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 main
 
 import (
         "debug/goobj"
         "fmt"
         "go/build"
@@ skipping 95 matching lines @@
         Name     string   // name of section: "text", "rodata", "noptrbss", and so on
         VirtAddr Addr     // virtual memory address of section base
         Size     Addr     // size of section in memory
         Align    Addr     // required alignment
         InFile   bool     // section has image data in file (like data, unlike bss)
         Syms     []*Sym   // symbols stored in section
         Segment  *Segment // segment containing section
 }
 
 func (p *Prog) errorf(format string, args ...interface{}) {
-        // TODO(rsc): Provide a way to redirect.

[iant, 2014/01/08 21:14:58]

Seems like p.Error is the way to redirect, you just need to call it.

[rsc, 2014/01/09 22:00:50]

Done.

-        fmt.Fprintf(os.Stderr, format+"\n", args...)
+        if p.Error != nil {
+                p.Error(fmt.Sprintf(format, args...))
+        } else {
+                fmt.Fprintf(os.Stderr, format+"\n", args...)
+        }
         p.NumError++
 }
 
 // link is the one-stop convenience method for running a link.
 // It writes to w the object file generated from using mainFile as the main package.
 func (p *Prog) link(w io.Writer, mainFile string) {
         p.init()
         p.scan(mainFile)
         if p.NumError > 0 {
                 return
@@ skipping 33 matching lines @@
         }
 
         // Derive internal context.
         p.formatter = formatters[p.Format]
         if p.formatter == nil {
                 p.errorf("unknown output file format %q", p.Format)
                 return
         }
 }
 
-// goosFormat records the default format each known GOOS value.

[iant, 2014/01/08 21:14:58]

s/format each/format for each/

[rsc, 2014/01/09 22:00:50]

Done.

+// goosFormat records the default format for each known GOOS value.
 var goosFormat = map[string]string{
         "darwin": "darwin",
 }
 
 // formatters records the format implementation for each known format value.
 var formatters = map[string]formatter{
         "darwin": machoFormat{},
 }