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C++可执行文件的生成

发表于 更新于 分类于 ，
C++：算法之外的故事系列之一，讲解一般cpp文件的生成过程。

头文件、源文件和库

一般惯例

  • 头文件：包括函数、结构体、类、变量等的声明，一般不包含核心变量及函数的定义与实例。
  • 源文件：包括函数的定义、变量的定义、类的定义等成分。
  • 库文件：包括函数的定义、变量的定义、类的定义等成分，由源文件生成。

举例：cstdio

头文件：cstdio

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...
int __cdecl printf(const char * __restrict__ _Format,...);
...

源文件：main.cpp

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#include <cstdio>
#include <cstdlib>
int main()
{
    printf("hello, world!\n");
    return EXIT_SUCCESS;
}

库文件：libstdc++.a

可执行程序的生成流程

编译器及版本

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g++.exe (x86_64-win32-seh-rev3, Built by MinGW-W64 project) 12.1.0
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

预处理

对源文件所有预处理代码进行转义等操作。

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g++ -E main.cpp -o main.cxx

文件：main.cxx

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# 0 ".\\main.cpp"
# 0 "<built-in>"
# 0 "<command-line>"
# 1 ".\\main.cpp"
# 1 "C:/Users/shuij/Documents/portables/mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/include/c++/cstdio" 1 3
# 39 "C:/Users/shuij/Documents/portables/mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/include/c++/cstdio" 3
       
# 40 "C:/Users/shuij/Documents/portables/mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/include/c++/cstdio" 3

# 1 "C:/Users/shuij/Documents/portables/mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/include/c++/x86_64-w64-mingw32/bits/c++config.h" 1 3
# 296 "C:/Users/shuij/Documents/portables/mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/include/c++/x86_64-w64-mingw32/bits/c++config.h" 3

# 296 "C:/Users/shuij/Documents/portables/mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/include/c++/x86_64-w64-mingw32/bits/c++config.h" 3
namespace std
{
  typedef long long unsigned int size_t;
  typedef long long int ptrdiff_t;


  typedef decltype(nullptr) nullptr_t;


#pragma GCC visibility push(default)


  extern "C++" __attribute__ ((__noreturn__, __always_inline__))
  inline void __terminate() noexcept
  {
    void terminate() noexcept __attribute__ ((__noreturn__));
    terminate();
  }
#pragma GCC visibility pop
}
# 329 "C:/Users/shuij/Documents/portables/mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/include/c++/x86_64-w64-mingw32/bits/c++config.h" 3
namespace std
{
  inline namespace __cxx11 __attribute__((__abi_tag__ ("cxx11"))) { }
}
namespace __gnu_cxx
{
  inline namespace __cxx11 __attribute__((__abi_tag__ ("cxx11"))) { }
}
# 508 "C:/Users/shuij/Documents/portables/mingw64/lib/gcc/x86_64-w64-mingw32/12.1.0/include/c++/x86_64-w64-mingw32/bits/c++config.h" 3

...
// 省略2100行
...

namespace std
{

  using ::__gnu_cxx::lldiv_t;

  using ::__gnu_cxx::_Exit;

  using ::__gnu_cxx::llabs;
  using ::__gnu_cxx::div;
  using ::__gnu_cxx::lldiv;

  using ::__gnu_cxx::atoll;
  using ::__gnu_cxx::strtof;
  using ::__gnu_cxx::strtoll;
  using ::__gnu_cxx::strtoull;
  using ::__gnu_cxx::strtold;
}



}
# 3 ".\\main.cpp" 2


# 4 ".\\main.cpp"
using namespace std;

int main()
{
    printf("hello, world!\n");
    return 
# 9 ".\\main.cpp" 3
          0
# 9 ".\\main.cpp"
                      ;
}

编译

将转义完成的C++文件转化为汇编代码

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g++ -S main.cxx -o main.s

文件：main.s 

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	.file	"main.cxx"
	.text
	.section	.text$_Z6printfPKcz,"x"
	.linkonce discard
	.globl	_Z6printfPKcz
	.def	_Z6printfPKcz;	.scl	2;	.type	32;	.endef
	.seh_proc	_Z6printfPKcz
_Z6printfPKcz:
.LFB10:
	pushq	%rbp
	.seh_pushreg	%rbp
	pushq	%rbx
	.seh_pushreg	%rbx
	subq	$56, %rsp
	.seh_stackalloc	56
	leaq	48(%rsp), %rbp
	.seh_setframe	%rbp, 48
	.seh_endprologue
	movq	%rcx, 32(%rbp)
	movq	%rdx, 40(%rbp)
	movq	%r8, 48(%rbp)
	movq	%r9, 56(%rbp)
	leaq	40(%rbp), %rax
	movq	%rax, -16(%rbp)
	movq	-16(%rbp), %rbx
	movl	$1, %ecx
	movq	__imp___acrt_iob_func(%rip), %rax
	call	*%rax
	movq	%rax, %rcx
	movq	32(%rbp), %rax
	movq	%rbx, %r8
	movq	%rax, %rdx
	call	__mingw_vfprintf
	movl	%eax, -4(%rbp)
	movl	-4(%rbp), %eax
	addq	$56, %rsp
	popq	%rbx
	popq	%rbp
	ret
	.seh_endproc
	.def	__main;	.scl	2;	.type	32;	.endef
	.section .rdata,"dr"
.LC0:
	.ascii "hello, world!\12\0"
	.text
	.globl	main
	.def	main;	.scl	2;	.type	32;	.endef
	.seh_proc	main
main:
.LFB80:
	pushq	%rbp
	.seh_pushreg	%rbp
	movq	%rsp, %rbp
	.seh_setframe	%rbp, 0
	subq	$32, %rsp
	.seh_stackalloc	32
	.seh_endprologue
	call	__main
	leaq	.LC0(%rip), %rax
	movq	%rax, %rcx
	call	_Z6printfPKcz
	movl	$0, %eax
	addq	$32, %rsp
	popq	%rbp
	ret
	.seh_endproc
	.ident	"GCC: (x86_64-win32-seh-rev3, Built by MinGW-W64 project) 12.1.0"
	.def	__mingw_vfprintf;	.scl	2;	.type	32;	.endef

汇编

将汇编代码转化为二进制机器码

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g++ -c main.s -o main.o

链接

将所有二进制机器码进行统一，生成可执行文件

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g++ main.o -o main.exe

一步生成

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g++ main.cpp -o main.exe

总览