减少GCC目标EXE代码大小？ [英] Reducing GCC target EXE code size?

问题描述

当我编译一个无操作程序时：

  int main（void）
 {
返回0; 
 
  

使用各种编译器：

GCC（类似于LLVM的结果）：给出一个10-KiB可执行文件（编译时使用 -s ） >
$ b

• 部分： .CRT ， .bss ， .data ， .idata ， .rdata ， .text ， .tls




• 取决于 msvcrt.dll 和 kernel32.dll

MSVC 2010：提供了一个5.5 KiB可执行文件（用 / MD / Ox p>

• 部分： .data ， .rdata ， .reloc ， .text




• 取决于 msvcr100.dll 和 kernel32.dll




• 可以通过合并 .rdata 和 .text

Windows Driver Kit 7.1：提供6.5 KiB可执行文件（使用 / MD / Ox ，与 msvcrt_winxp.obj 链接以允许它在XP上运行）

• 部分： .data ， .rdata ， .text




• 取决于 msvcrt.dll 和 kernel32.dll

可以通过合并 .rdata
• $ c $> .text

Windows 2003 Driver Development Kit：提供3.5 KiB可执行文件

• 部分： .data ， .rdata ， .text




• 取决于 msvcrt.dll




• 合并 .rdata 与 .text



Tiny C编译器（TCC）：提供1.5 KiB可执行文件





• 部分： .data ， .text




• 取决于 msvcrt.dll

所以我想这个问题很简单：

是否有可能进一步减少GCC或LLVM的目标可执行文件大小，以便它们是更接近裸露的最小可能，同时仍然链接到 msvcrt.dll ？

（编辑：我是显然不是找像 UPX 等打包机）。

解决方案

这并不是一件特别有意义的事情。它可能会消除一些事情，但只要你有一个实际上做了什么的程序，那么它会再次将这些东西拉回来。

例如，在另一个平台上（我没有做太多Windows操作），程序的最小尺寸比你想象的要大，因为每个程序都有一个atexit处理程序来清理。该处理程序有一个可能的错误情况，这意味着它拉入printf和所有I / O的东西。 Atexit本身也吸引了malloc和所有的内存交付的东西。毫无疑问，除此之外还有其他一些位。最终结果是一个400KB的静态二进制大小。这在一个没有操作的程序中很烦人，但实际上所有的程序都需要这个东西，所以这是一个有争议的问题。

一般来说，如果你想最小化程序大小，使用 -Os 进行编译，并尝试使用 -flto 或 -fwhole-program （但这最后需要对构建过程进行大量更改）。另外，不要使用 -g ，并且去掉最后的二进制文件（如果不能打破这些文件的话）。

When I compiled a no-op program:

int main(void)
{
    return 0;
}

with various compilers:

• GCC (similar result to LLVM as well): Gave a 10-KiB executable (compiled with -s)

  • Sections: .CRT, .bss, .data, .idata, .rdata, .text, .tls

  • Depends on msvcrt.dll and kernel32.dll

• MSVC 2010: Gave a 5.5 KiB executable (compiled with /MD /Ox)

  • Sections: .data, .rdata, .reloc, .text

  • Depends on msvcr100.dll and kernel32.dll

  • Could have been further reduced by merging .rdata with .text

• Windows Driver Kit 7.1: Gave a 6.5 KiB executable (compiled with /MD /Ox, linked with msvcrt_winxp.obj to allow it to run on XP)

  • Sections: .data, .rdata, .text

  • Depends on msvcrt.dll and kernel32.dll

  • Could have been further reduced by merging .rdata with .text

• Windows 2003 Driver Development Kit: Gave a 3.5 KiB executable

  • Sections: .data, .rdata, .text

  • Depends on msvcrt.dll

  • Could have been further reduced by merging .rdata with .text

• Tiny C Compiler (TCC): Gave a 1.5 KiB executable

  • Sections: .data, .text

  • Depends on msvcrt.dll

So I guess the question is simple:

Is it possible to further reduce GCC or LLVM's target executable sizes so that they are closer to the bare-minimum possible, while still linking to msvcrt.dll?

(Edit: I'm obviously not looking for packers like UPX, etc.)

解决方案

This isn't a particularly meaningful thing to do. It might be possible to eliminate a few things, but as soon as you have a program that actually does anything then it'll pull those things straight back in again.

For example, on another platform (I don't do much Windows stuff), the minimum size for a program is larger than you would think because every program has an atexit handler to clean up. That handler has a possible error case which means it pull in printf and all the I/O stuff. Atexit itself also pulls in malloc and all the memory handing stuff. And no doubt there's a few other bits besides. The end result is a 400KB static binary size. That's annoying in a no-op program, but in reality all programs would need this stuff, so it's a moot point.

In general, if you want to minimise program size, compile with -Os, and try to use -flto or -fwhole-program (but this last will need lots of changes to your build procedure). Also, don't use -g, and do strip the final binaries (if that doesn't break them).

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