Skip to content

G
golang
Commit e1544d3b authored by Austin Clements's avatar Austin Clements
Browse files
Options

dwbug/elf: support old-style compressed DWARF 

GCC and LLVM support zlib-compressing DWARF debug sections (and
there's some evidence that this may be happening by default in some
circumstances now).

Add support for reading compressed DWARF sections. Since ELF
relocations apply to the decompressed data, decompression is done
before applying relocations. Since relcations are applied by
debug/elf, decompression must also be handled there.

Note that this is different from compressed ELF sections, which is a
more general mechanism used by very recent versions of GCC.

Updates #11773.

Change-Id: I3f4bf1b04d0802cc1e8fcb7c2a5fcf6c467c5089
Reviewed-on: https://go-review.googlesource.com/17340Reviewed-by: 's avatarIan Lance Taylor <iant@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: 's avatarRuss Cox <rsc@golang.org>
parent 606d9a7e
Hide whitespace changes
Inline Side-by-side
Showing with 60 additions and 6 deletions
src/cmd/dist/deps.go
View file @ e1544d3b
......@@ -5,11 +5,13 @@ package main
var builddeps = map[string][]string{
"bufio": {"bytes", "errors", "internal/race", "io", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sync", "sync/atomic", "unicode", "unicode/utf8"},
"bytes": {"errors", "internal/race", "io", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sync", "sync/atomic", "unicode", "unicode/utf8"},
"compress/flate": {"bufio", "bytes", "errors", "fmt", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "math", "os", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "sync", "sync/atomic", "syscall", "time", "unicode", "unicode/utf16", "unicode/utf8"},
"compress/zlib": {"bufio", "bytes", "compress/flate", "errors", "fmt", "hash", "hash/adler32", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "math", "os", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "sync", "sync/atomic", "syscall", "time", "unicode", "unicode/utf16", "unicode/utf8"},
"container/heap": {"runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort"},
"crypto": {"errors", "hash", "internal/race", "io", "math", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "strconv", "sync", "sync/atomic", "unicode/utf8"},
"crypto/sha1": {"crypto", "errors", "hash", "internal/race", "io", "math", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "strconv", "sync", "sync/atomic", "unicode/utf8"},
"debug/dwarf": {"encoding/binary", "errors", "fmt", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "math", "os", "path", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "time", "unicode", "unicode/utf16", "unicode/utf8"},
"debug/elf": {"bytes", "debug/dwarf", "encoding/binary", "errors", "fmt", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "math", "os", "path", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "time", "unicode", "unicode/utf16", "unicode/utf8"},
"debug/elf": {"bufio", "bytes", "compress/flate", "compress/zlib", "debug/dwarf", "encoding/binary", "errors", "fmt", "hash", "hash/adler32", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "math", "os", "path", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "time", "unicode", "unicode/utf16", "unicode/utf8"},
"debug/macho": {"bytes", "debug/dwarf", "encoding/binary", "errors", "fmt", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "math", "os", "path", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "time", "unicode", "unicode/utf16", "unicode/utf8"},
"encoding": {"runtime", "runtime/internal/atomic", "runtime/internal/sys"},
"encoding/base64": {"errors", "internal/race", "io", "math", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "strconv", "sync", "sync/atomic", "unicode/utf8"},
......@@ -25,6 +27,7 @@ var builddeps = map[string][]string{
"go/scanner": {"bytes", "errors", "fmt", "go/token", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "math", "os", "path/filepath", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "time", "unicode", "unicode/utf16", "unicode/utf8"},
"go/token": {"errors", "fmt", "internal/race", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "math", "os", "reflect", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "sync", "sync/atomic", "syscall", "time", "unicode/utf16", "unicode/utf8"},
"hash": {"errors", "internal/race", "io", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sync", "sync/atomic"},
"hash/adler32": {"errors", "hash", "internal/race", "io", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sync", "sync/atomic"},
"internal/race": {"runtime", "runtime/internal/atomic", "runtime/internal/sys"},
"internal/singleflight": {"internal/race", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sync", "sync/atomic"},
"internal/syscall/windows": {"errors", "internal/race", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sync", "sync/atomic", "syscall", "unicode/utf16"},
......@@ -57,5 +60,5 @@ var builddeps = map[string][]string{
"unicode": {"runtime", "runtime/internal/atomic", "runtime/internal/sys"},
"unicode/utf16": {"runtime", "runtime/internal/atomic", "runtime/internal/sys"},
"unicode/utf8": {"runtime", "runtime/internal/atomic", "runtime/internal/sys"},
"cmd/go": {"bufio", "bytes", "container/heap", "crypto", "crypto/sha1", "debug/dwarf", "debug/elf", "debug/macho", "encoding", "encoding/base64", "encoding/binary", "encoding/json", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "hash", "internal/race", "internal/singleflight", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "io/ioutil", "log", "math", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
"cmd/go": {"bufio", "bytes", "compress/flate", "compress/zlib", "container/heap", "crypto", "crypto/sha1", "debug/dwarf", "debug/elf", "debug/macho", "encoding", "encoding/base64", "encoding/binary", "encoding/json", "errors", "flag", "fmt", "go/ast", "go/build", "go/doc", "go/parser", "go/scanner", "go/token", "hash", "hash/adler32", "internal/race", "internal/singleflight", "internal/syscall/windows", "internal/syscall/windows/registry", "io", "io/ioutil", "log", "math", "net/url", "os", "os/exec", "os/signal", "path", "path/filepath", "reflect", "regexp", "regexp/syntax", "runtime", "runtime/internal/atomic", "runtime/internal/sys", "sort", "strconv", "strings", "sync", "sync/atomic", "syscall", "text/template", "text/template/parse", "time", "unicode", "unicode/utf16", "unicode/utf8"},
}
src/debug/elf/file.go
View file @ e1544d3b
......@@ -7,6 +7,7 @@ package elf
import (
"bytes"
"compress/zlib"
"debug/dwarf"
"encoding/binary"
"errors"
......@@ -863,6 +864,22 @@ func (f *File) DWARF() (*dwarf.Data, error) {
return nil, err
}
if len(b) >= 12 && string(b[:4]) == "ZLIB" {
dlen := binary.BigEndian.Uint64(b[4:12])
dbuf := make([]byte, dlen)
r, err := zlib.NewReader(bytes.NewBuffer(b[12:]))
if err != nil {
return nil, err
}
if _, err := io.ReadFull(r, dbuf); err != nil {
return nil, err
}
if err := r.Close(); err != nil {
return nil, err
}
b = dbuf
}
for _, r := range f.Sections {
if r.Type != SHT_RELA && r.Type != SHT_REL {
continue
......@@ -887,17 +904,23 @@ func (f *File) DWARF() (*dwarf.Data, error) {
// Don't bother loading others.
var dat = map[string][]byte{"abbrev": nil, "info": nil, "str": nil, "line": nil}
for i, s := range f.Sections {
if !strings.HasPrefix(s.Name, ".debug_") {
suffix := ""
switch {
case strings.HasPrefix(s.Name, ".debug_"):
suffix = s.Name[7:]
case strings.HasPrefix(s.Name, ".zdebug_"):
suffix = s.Name[8:]
default:
continue
}
if _, ok := dat[s.Name[7:]]; !ok {
if _, ok := dat[suffix]; !ok {
continue
}
b, err := sectionData(i, s)
if err != nil {
return nil, err
}
dat[s.Name[7:]] = b
dat[suffix] = b
}
d, err := dwarf.New(dat["abbrev"], nil, nil, dat["info"], dat["line"], nil, nil, dat["str"])
......
src/debug/elf/file_test.go
View file @ e1544d3b
......@@ -514,6 +514,34 @@ func TestDWARFRelocations(t *testing.T) {
}
}
func TestCompressedDWARF(t *testing.T) {
// Test file built with GCC 4.8.4 and as 2.24 using:
// gcc -Wa,--compress-debug-sections -g -c -o zdebug-test-gcc484-x86-64.obj hello.c
f, err := Open("testdata/zdebug-test-gcc484-x86-64.obj")
if err != nil {
t.Fatal(err)
}
dwarf, err := f.DWARF()
if err != nil {
t.Fatal(err)
}
reader := dwarf.Reader()
n := 0
for {
entry, err := reader.Next()
if err != nil {
t.Fatal(err)
}
if entry == nil {
break
}
n++
}
if n != 18 {
t.Fatalf("want %d DWARF entries, got %d", 18, n)
}
}
func TestNoSectionOverlaps(t *testing.T) {
// Ensure 6l outputs sections without overlaps.
if runtime.GOOS != "linux" && runtime.GOOS != "freebsd" {
......
src/go/build/deps_test.go
View file @ e1544d3b
......@@ -218,7 +218,7 @@ var pkgDeps = map[string][]string{
"database/sql": {"L4", "container/list", "database/sql/driver"},
"database/sql/driver": {"L4", "time"},
"debug/dwarf": {"L4"},
"debug/elf": {"L4", "OS", "debug/dwarf"},
"debug/elf": {"L4", "OS", "debug/dwarf", "compress/zlib"},
"debug/gosym": {"L4"},
"debug/macho": {"L4", "OS", "debug/dwarf"},
"debug/pe": {"L4", "OS", "debug/dwarf"},
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment