From: Russ Cox Date: Mon, 14 Apr 2014 14:58:49 +0000 (-0400) Subject: cmd/objdump: rewrite in Go X-Git-Tag: go1.3beta1~102 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=0d441a088d2cb23af32dae473aea989830d11055;p=gostls13.git cmd/objdump: rewrite in Go Update cmd/dist not to build the C version. Update cmd/go to install the Go version to the tool directory. Update #7452 This is the basic logic needed for objdump, and it works well enough to support the pprof list and weblist commands. A real disassembler needs to be added in order to support the pprof disasm command and the per-line assembly displays in weblist. That's still to come. Probably objdump will move to go.tools when the disassembler is added, but it can stay here for now. LGTM=minux.ma R=golang-codereviews, minux.ma CC=golang-codereviews, iant, r https://golang.org/cl/87580043 --- diff --git a/src/cmd/dist/build.c b/src/cmd/dist/build.c index be05b82f19..3ef9f6592c 100644 --- a/src/cmd/dist/build.c +++ b/src/cmd/dist/build.c @@ -1332,7 +1332,6 @@ static char *buildorder[] = { "misc/pprof", - "cmd/objdump", "cmd/prof", "cmd/cc", // must be before c @@ -1409,7 +1408,6 @@ static char *cleantab[] = { "cmd/cc", "cmd/gc", "cmd/go", - "cmd/objdump", "cmd/prof", "lib9", "libbio", diff --git a/src/cmd/go/pkg.go b/src/cmd/go/pkg.go index 0964008dd8..59c5d357e3 100644 --- a/src/cmd/go/pkg.go +++ b/src/cmd/go/pkg.go @@ -313,6 +313,7 @@ var goTools = map[string]targetDir{ "cmd/fix": toTool, "cmd/link": toTool, "cmd/nm": toTool, + "cmd/objdump": toTool, "cmd/pack": toTool, "cmd/yacc": toTool, "code.google.com/p/go.tools/cmd/cover": toTool, diff --git a/src/cmd/objdump/main.c b/src/cmd/objdump/main.c deleted file mode 100644 index b684be7fbe..0000000000 --- a/src/cmd/objdump/main.c +++ /dev/null @@ -1,68 +0,0 @@ -// Copyright 2012 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. - -/* - * objdump simulation - only enough to make pprof work on Macs - */ - -#include -#include -#include -#include - -void -usage(void) -{ - fprint(2, "usage: objdump binary start stop\n"); - fprint(2, "Disassembles binary from PC start up to stop.\n"); - exits("usage"); -} - -void -main(int argc, char **argv) -{ - int fd, n; - uvlong pc, start, stop; - Fhdr fhdr; - Biobuf bout; - char buf[1024]; - Map *text; - - ARGBEGIN{ - default: - usage(); - }ARGEND - - if(argc != 3) - usage(); - start = strtoull(argv[1], 0, 16); - stop = strtoull(argv[2], 0, 16); - - fd = open(argv[0], OREAD); - if(fd < 0) - sysfatal("open %s: %r", argv[0]); - if(crackhdr(fd, &fhdr) <= 0) - sysfatal("crackhdr: %r"); - machbytype(fhdr.type); - if(syminit(fd, &fhdr) <= 0) - sysfatal("syminit: %r"); - text = loadmap(nil, fd, &fhdr); - if(text == nil) - sysfatal("loadmap: %r"); - - Binit(&bout, 1, OWRITE); - for(pc=start; pcdas(text, pc, 0, buf, sizeof buf); - Bprint(&bout, " %llx: %s\n", pc, buf); - n = machdata->instsize(text, pc); - if(n <= 0) - break; - pc += n; - } - Bflush(&bout); - exits(0); -} diff --git a/src/cmd/objdump/main.go b/src/cmd/objdump/main.go new file mode 100644 index 0000000000..222ee32f35 --- /dev/null +++ b/src/cmd/objdump/main.go @@ -0,0 +1,162 @@ +// Copyright 2012 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. + +// objdump simulation - only enough to make pprof work on Macs + +package main + +import ( + "bufio" + "debug/elf" + "debug/gosym" + "debug/macho" + "debug/pe" + "flag" + "fmt" + "log" + "os" + "strconv" +) + +func printUsage(w *os.File) { + fmt.Fprintf(w, "usage: objdump binary start end\n") + fmt.Fprintf(w, "disassembles binary from start PC to end PC.\n") +} + +func usage() { + printUsage(os.Stderr) + os.Exit(2) +} + +func main() { + log.SetFlags(0) + log.SetPrefix("objdump: ") + + flag.Usage = usage + flag.Parse() + if flag.NArg() != 3 { + usage() + } + + f, err := os.Open(flag.Arg(0)) + if err != nil { + log.Fatal(err) + } + + textStart, textData, symtab, pclntab, err := loadTables(f) + if err != nil { + log.Fatalf("reading %s: %v", flag.Arg(0), err) + } + + pcln := gosym.NewLineTable(pclntab, textStart) + tab, err := gosym.NewTable(symtab, pcln) + if err != nil { + log.Fatalf("reading %s: %v", flag.Arg(0), err) + } + + start, err := strconv.ParseUint(flag.Arg(1), 0, 64) + if err != nil { + log.Fatalf("invalid start PC: %v", err) + } + end, err := strconv.ParseUint(flag.Arg(2), 0, 64) + if err != nil { + log.Fatalf("invalid end PC: %v", err) + } + + stdout := bufio.NewWriter(os.Stdout) + + // For now, find spans of same PC/line/fn and + // emit them as having dummy instructions. + var ( + spanPC uint64 + spanFile string + spanLine int + spanFn *gosym.Func + ) + + flush := func(endPC uint64) { + if spanPC == 0 { + return + } + fmt.Fprintf(stdout, "%s:%d\n", spanFile, spanLine) + for pc := spanPC; pc < endPC; pc++ { + // TODO(rsc): Disassemble instructions here. + if textStart <= pc && pc-textStart < uint64(len(textData)) { + fmt.Fprintf(stdout, " %x: byte %#x\n", pc, textData[pc-textStart]) + } else { + fmt.Fprintf(stdout, " %x: ?\n", pc) + } + } + spanPC = 0 + } + + for pc := start; pc < end; pc++ { + file, line, fn := tab.PCToLine(pc) + if file != spanFile || line != spanLine || fn != spanFn { + flush(pc) + spanPC, spanFile, spanLine, spanFn = pc, file, line, fn + } + } + flush(end) + + stdout.Flush() +} + +func loadTables(f *os.File) (textStart uint64, textData, symtab, pclntab []byte, err error) { + if obj, err := elf.NewFile(f); err == nil { + if sect := obj.Section(".text"); sect != nil { + textStart = sect.Addr + textData, _ = sect.Data() + } + if sect := obj.Section(".gosymtab"); sect != nil { + if symtab, err = sect.Data(); err != nil { + return 0, nil, nil, nil, err + } + } + if sect := obj.Section(".gopclntab"); sect != nil { + if pclntab, err = sect.Data(); err != nil { + return 0, nil, nil, nil, err + } + } + return textStart, textData, symtab, pclntab, nil + } + + if obj, err := macho.NewFile(f); err == nil { + if sect := obj.Section("__text"); sect != nil { + textStart = sect.Addr + textData, _ = sect.Data() + } + if sect := obj.Section("__gosymtab"); sect != nil { + if symtab, err = sect.Data(); err != nil { + return 0, nil, nil, nil, err + } + } + if sect := obj.Section("__gopclntab"); sect != nil { + if pclntab, err = sect.Data(); err != nil { + return 0, nil, nil, nil, err + } + } + return textStart, textData, symtab, pclntab, nil + } + + if obj, err := pe.NewFile(f); err == nil { + if sect := obj.Section(".text"); sect != nil { + textStart = uint64(sect.VirtualAddress) + textData, _ = sect.Data() + } + if sect := obj.Section(".gosymtab"); sect != nil { + if symtab, err = sect.Data(); err != nil { + return 0, nil, nil, nil, err + } + } + if sect := obj.Section(".gopclntab"); sect != nil { + if pclntab, err = sect.Data(); err != nil { + return 0, nil, nil, nil, err + } + } + return textStart, textData, symtab, pclntab, nil + } + + return 0, nil, nil, nil, fmt.Errorf("unrecognized binary format") +}