i know --ldflags="-s -w"
will make Go binary size smaller, but without comparing to the one without ldflags, how do we know whether Go binary compiled with or without ldflags="-s -w"
?
如何检查golang二进制文件是否使用--ldflags =“-s -w”进行编译
- 写回答
- 好问题 0 提建议
- 追加酬金
- 关注问题
- 邀请回答
-
1条回答 默认 最新
- dongzhang4301 2017-05-24 21:40关注
Disclaimer first: I'm no expert of compilation toolchains and executable file formats. I'll try not to say stupid things, but correct me if you see any mistake !
I ran those tests on an ArchLinux laptop, with x86_64 architecture. Go version is 1.8.1.
First, we need to know where those flags are actually used:
$ go help build ... -ldflags 'flag list' arguments to pass on each go tool link invocation ...
Apparently, flags are merely passed to the
go tool link
invocation. Looking at the help, we have a bit more information:$ go tool link ... -s disable symbol table ... -w disable DWARF generation ...
Taken from the short introduction to ELF that I found here, here is the header text concerning the Symbol Table:
An object file’s symbol table holds information needed to locate and relocate a program’s symbolic definitions and references.
As for DWARF, this is a format for debugging data.
From there, how do we know if a binary has a symbol table, or DWARF enabled ? The answer lies in ELF sections. There are probably other ways, but it is the one I found and is easy to check for. Here are the rules that I've used to determine if a Golang binary has been compiled with
-ldflags='-s'
or-ldflags='-w'
:- If a Go binary has a symbol table, the section
.symtab
is present - If a Go binary has DWARF debug, the section
.debug_info
is present. This section is not the only one to be present, but serves as an indicator.
On Linux, there are some tools which can read section names to extract those informations.
readelf
andnm
are examples, yet probably more exist.It also turns out that Go provide a
debug/elf
package which can be used to get those informations. Here is a sample program that does this job:package main import "fmt" import "os" import "debug/elf" func main() { fileName := "path/to/main" fp, err := elf.Open(fileName) if err != nil { fmt.Println(err) os.Exit(1) } symtab := fp.Section(".symtab") if symtab == nil { fmt.Println("No Symbol Table : compiled with -ldflags='-s'") } debugInfo := fp.Section(".debug_info") if debugInfo == nil { fmt.Println("No DWARF data : compiled with -ldflags='-w'") } }
I tested this program against the basic Golang Hello World, using no flags, only the
-s
flag, only the-w
flag and both-s -w
flags. I noted that while compiling with-s
only, it also removed DWARF data, but I did not search why. Aside from that, the results were as expected.Though ELF was the focus format, the same method can be applied for Windows executables (there is a
debug/pe
package in Golang).本回答被题主选为最佳回答 , 对您是否有帮助呢?解决 无用评论 打赏 举报 - If a Go binary has a symbol table, the section
悬赏问题
- ¥100 求数学坐标画圆以及直线的算法
- ¥100 c语言,请帮蒟蒻写一个题的范例作参考
- ¥15 名为“Product”的列已属于此 DataTable
- ¥15 安卓adb backup备份应用数据失败
- ¥15 eclipse运行项目时遇到的问题
- ¥15 关于#c##的问题:最近需要用CAT工具Trados进行一些开发
- ¥15 南大pa1 小游戏没有界面,并且报了如下错误,尝试过换显卡驱动,但是好像不行
- ¥15 自己瞎改改,结果现在又运行不了了
- ¥15 链式存储应该如何解决
- ¥15 没有证书,nginx怎么反向代理到只能接受https的公网网站