`
yaojingguo
  • 浏览: 208999 次
  • 性别: Icon_minigender_1
  • 来自: 北京
社区版块
存档分类
最新评论

Source code change effect on object code

 
阅读更多

C code:

 

 

#include <stdio.h>
// change no's type from int to long long
long long func(long long no) 
{
	return no + 1;	
}

int main(int argc, const char *argv[]) {
	int i;
	i = 100;
	func(i);	
	return 0;
}

 Run 'gcc -g' to compile it. Then run 'objdump -S a.out' produce:

 

 

a.out:     file format elf32-i386


Disassembly of section .init:

08048298 <_init>:
 8048298:	55                   	push   %ebp
 8048299:	89 e5                	mov    %esp,%ebp
 804829b:	53                   	push   %ebx
 804829c:	83 ec 04             	sub    $0x4,%esp
 804829f:	e8 00 00 00 00       	call   80482a4 <_init+0xc>
 80482a4:	5b                   	pop    %ebx
 80482a5:	81 c3 50 1d 00 00    	add    $0x1d50,%ebx
 80482ab:	8b 93 fc ff ff ff    	mov    -0x4(%ebx),%edx
 80482b1:	85 d2                	test   %edx,%edx
 80482b3:	74 05                	je     80482ba <_init+0x22>
 80482b5:	e8 1e 00 00 00       	call   80482d8 <__gmon_start__@plt>
 80482ba:	e8 d1 00 00 00       	call   8048390 <frame_dummy>
 80482bf:	e8 bc 01 00 00       	call   8048480 <__do_global_ctors_aux>
 80482c4:	58                   	pop    %eax
 80482c5:	5b                   	pop    %ebx
 80482c6:	c9                   	leave  
 80482c7:	c3                   	ret    

Disassembly of section .plt:

080482c8 <__gmon_start__@plt-0x10>:
 80482c8:	ff 35 f8 9f 04 08    	pushl  0x8049ff8
 80482ce:	ff 25 fc 9f 04 08    	jmp    *0x8049ffc
 80482d4:	00 00                	add    %al,(%eax)
	...

080482d8 <__gmon_start__@plt>:
 80482d8:	ff 25 00 a0 04 08    	jmp    *0x804a000
 80482de:	68 00 00 00 00       	push   $0x0
 80482e3:	e9 e0 ff ff ff       	jmp    80482c8 <_init+0x30>

080482e8 <__libc_start_main@plt>:
 80482e8:	ff 25 04 a0 04 08    	jmp    *0x804a004
 80482ee:	68 08 00 00 00       	push   $0x8
 80482f3:	e9 d0 ff ff ff       	jmp    80482c8 <_init+0x30>

Disassembly of section .text:

08048300 <_start>:
 8048300:	31 ed                	xor    %ebp,%ebp
 8048302:	5e                   	pop    %esi
 8048303:	89 e1                	mov    %esp,%ecx
 8048305:	83 e4 f0             	and    $0xfffffff0,%esp
 8048308:	50                   	push   %eax
 8048309:	54                   	push   %esp
 804830a:	52                   	push   %edx
 804830b:	68 10 84 04 08       	push   $0x8048410
 8048310:	68 20 84 04 08       	push   $0x8048420
 8048315:	51                   	push   %ecx
 8048316:	56                   	push   %esi
 8048317:	68 d4 83 04 08       	push   $0x80483d4
 804831c:	e8 c7 ff ff ff       	call   80482e8 <__libc_start_main@plt>
 8048321:	f4                   	hlt    
 8048322:	90                   	nop
 8048323:	90                   	nop
 8048324:	90                   	nop
 8048325:	90                   	nop
 8048326:	90                   	nop
 8048327:	90                   	nop
 8048328:	90                   	nop
 8048329:	90                   	nop
 804832a:	90                   	nop
 804832b:	90                   	nop
 804832c:	90                   	nop
 804832d:	90                   	nop
 804832e:	90                   	nop
 804832f:	90                   	nop

08048330 <__do_global_dtors_aux>:
 8048330:	55                   	push   %ebp
 8048331:	89 e5                	mov    %esp,%ebp
 8048333:	53                   	push   %ebx
 8048334:	83 ec 04             	sub    $0x4,%esp
 8048337:	80 3d 10 a0 04 08 00 	cmpb   $0x0,0x804a010
 804833e:	75 3f                	jne    804837f <__do_global_dtors_aux+0x4f>
 8048340:	a1 14 a0 04 08       	mov    0x804a014,%eax
 8048345:	bb 18 9f 04 08       	mov    $0x8049f18,%ebx
 804834a:	81 eb 14 9f 04 08    	sub    $0x8049f14,%ebx
 8048350:	c1 fb 02             	sar    $0x2,%ebx
 8048353:	83 eb 01             	sub    $0x1,%ebx
 8048356:	39 d8                	cmp    %ebx,%eax
 8048358:	73 1e                	jae    8048378 <__do_global_dtors_aux+0x48>
 804835a:	8d b6 00 00 00 00    	lea    0x0(%esi),%esi
 8048360:	83 c0 01             	add    $0x1,%eax
 8048363:	a3 14 a0 04 08       	mov    %eax,0x804a014
 8048368:	ff 14 85 14 9f 04 08 	call   *0x8049f14(,%eax,4)
 804836f:	a1 14 a0 04 08       	mov    0x804a014,%eax
 8048374:	39 d8                	cmp    %ebx,%eax
 8048376:	72 e8                	jb     8048360 <__do_global_dtors_aux+0x30>
 8048378:	c6 05 10 a0 04 08 01 	movb   $0x1,0x804a010
 804837f:	83 c4 04             	add    $0x4,%esp
 8048382:	5b                   	pop    %ebx
 8048383:	5d                   	pop    %ebp
 8048384:	c3                   	ret    
 8048385:	8d 74 26 00          	lea    0x0(%esi,%eiz,1),%esi
 8048389:	8d bc 27 00 00 00 00 	lea    0x0(%edi,%eiz,1),%edi

08048390 <frame_dummy>:
 8048390:	55                   	push   %ebp
 8048391:	89 e5                	mov    %esp,%ebp
 8048393:	83 ec 18             	sub    $0x18,%esp
 8048396:	a1 1c 9f 04 08       	mov    0x8049f1c,%eax
 804839b:	85 c0                	test   %eax,%eax
 804839d:	74 12                	je     80483b1 <frame_dummy+0x21>
 804839f:	b8 00 00 00 00       	mov    $0x0,%eax
 80483a4:	85 c0                	test   %eax,%eax
 80483a6:	74 09                	je     80483b1 <frame_dummy+0x21>
 80483a8:	c7 04 24 1c 9f 04 08 	movl   $0x8049f1c,(%esp)
 80483af:	ff d0                	call   *%eax
 80483b1:	c9                   	leave  
 80483b2:	c3                   	ret    
 80483b3:	90                   	nop

080483b4 <func>:
#include <stdio.h>

long long func(long long no) 
{
 80483b4:	55                   	push   %ebp
 80483b5:	89 e5                	mov    %esp,%ebp
 80483b7:	83 ec 08             	sub    $0x8,%esp
 80483ba:	8b 45 08             	mov    0x8(%ebp),%eax
 80483bd:	89 45 f8             	mov    %eax,-0x8(%ebp)
 80483c0:	8b 45 0c             	mov    0xc(%ebp),%eax
 80483c3:	89 45 fc             	mov    %eax,-0x4(%ebp)
	return no + 1;	
 80483c6:	8b 45 f8             	mov    -0x8(%ebp),%eax
 80483c9:	8b 55 fc             	mov    -0x4(%ebp),%edx
 80483cc:	83 c0 01             	add    $0x1,%eax
 80483cf:	83 d2 00             	adc    $0x0,%edx
}
 80483d2:	c9                   	leave  
 80483d3:	c3                   	ret    

080483d4 <main>:

int main(int argc, const char *argv[]) {
 80483d4:	55                   	push   %ebp
 80483d5:	89 e5                	mov    %esp,%ebp
 80483d7:	83 e4 f8             	and    $0xfffffff8,%esp
 80483da:	83 ec 18             	sub    $0x18,%esp
	int i;
	i = 100;
 80483dd:	c7 44 24 14 64 00 00 	movl   $0x64,0x14(%esp)
 80483e4:	00 
	func(i);	
 80483e5:	8b 44 24 14          	mov    0x14(%esp),%eax
 80483e9:	89 c2                	mov    %eax,%edx
 80483eb:	c1 fa 1f             	sar    $0x1f,%edx
 80483ee:	89 04 24             	mov    %eax,(%esp)
 80483f1:	89 54 24 04          	mov    %edx,0x4(%esp)
 80483f5:	e8 ba ff ff ff       	call   80483b4 <func>
	return 0;
 80483fa:	b8 00 00 00 00       	mov    $0x0,%eax
}
 80483ff:	c9                   	leave  
 8048400:	c3                   	ret    
 8048401:	90                   	nop
 8048402:	90                   	nop
 8048403:	90                   	nop
 8048404:	90                   	nop
 8048405:	90                   	nop
 8048406:	90                   	nop
 8048407:	90                   	nop
 8048408:	90                   	nop
 8048409:	90                   	nop
 804840a:	90                   	nop
 804840b:	90                   	nop
 804840c:	90                   	nop
 804840d:	90                   	nop
 804840e:	90                   	nop
 804840f:	90                   	nop

08048410 <__libc_csu_fini>:
 8048410:	55                   	push   %ebp
 8048411:	89 e5                	mov    %esp,%ebp
 8048413:	5d                   	pop    %ebp
 8048414:	c3                   	ret    
 8048415:	8d 74 26 00          	lea    0x0(%esi,%eiz,1),%esi
 8048419:	8d bc 27 00 00 00 00 	lea    0x0(%edi,%eiz,1),%edi

08048420 <__libc_csu_init>:
 8048420:	55                   	push   %ebp
 8048421:	89 e5                	mov    %esp,%ebp
 8048423:	57                   	push   %edi
 8048424:	56                   	push   %esi
 8048425:	53                   	push   %ebx
 8048426:	e8 4f 00 00 00       	call   804847a <__i686.get_pc_thunk.bx>
 804842b:	81 c3 c9 1b 00 00    	add    $0x1bc9,%ebx
 8048431:	83 ec 1c             	sub    $0x1c,%esp
 8048434:	e8 5f fe ff ff       	call   8048298 <_init>
 8048439:	8d bb 18 ff ff ff    	lea    -0xe8(%ebx),%edi
 804843f:	8d 83 18 ff ff ff    	lea    -0xe8(%ebx),%eax
 8048445:	29 c7                	sub    %eax,%edi
 8048447:	c1 ff 02             	sar    $0x2,%edi
 804844a:	85 ff                	test   %edi,%edi
 804844c:	74 24                	je     8048472 <__libc_csu_init+0x52>
 804844e:	31 f6                	xor    %esi,%esi
 8048450:	8b 45 10             	mov    0x10(%ebp),%eax
 8048453:	89 44 24 08          	mov    %eax,0x8(%esp)
 8048457:	8b 45 0c             	mov    0xc(%ebp),%eax
 804845a:	89 44 24 04          	mov    %eax,0x4(%esp)
 804845e:	8b 45 08             	mov    0x8(%ebp),%eax
 8048461:	89 04 24             	mov    %eax,(%esp)
 8048464:	ff 94 b3 18 ff ff ff 	call   *-0xe8(%ebx,%esi,4)
 804846b:	83 c6 01             	add    $0x1,%esi
 804846e:	39 fe                	cmp    %edi,%esi
 8048470:	72 de                	jb     8048450 <__libc_csu_init+0x30>
 8048472:	83 c4 1c             	add    $0x1c,%esp
 8048475:	5b                   	pop    %ebx
 8048476:	5e                   	pop    %esi
 8048477:	5f                   	pop    %edi
 8048478:	5d                   	pop    %ebp
 8048479:	c3                   	ret    

0804847a <__i686.get_pc_thunk.bx>:
 804847a:	8b 1c 24             	mov    (%esp),%ebx
 804847d:	c3                   	ret    
 804847e:	90                   	nop
 804847f:	90                   	nop

08048480 <__do_global_ctors_aux>:
 8048480:	55                   	push   %ebp
 8048481:	89 e5                	mov    %esp,%ebp
 8048483:	53                   	push   %ebx
 8048484:	83 ec 04             	sub    $0x4,%esp
 8048487:	a1 0c 9f 04 08       	mov    0x8049f0c,%eax
 804848c:	83 f8 ff             	cmp    $0xffffffff,%eax
 804848f:	74 13                	je     80484a4 <__do_global_ctors_aux+0x24>
 8048491:	bb 0c 9f 04 08       	mov    $0x8049f0c,%ebx
 8048496:	66 90                	xchg   %ax,%ax
 8048498:	83 eb 04             	sub    $0x4,%ebx
 804849b:	ff d0                	call   *%eax
 804849d:	8b 03                	mov    (%ebx),%eax
 804849f:	83 f8 ff             	cmp    $0xffffffff,%eax
 80484a2:	75 f4                	jne    8048498 <__do_global_ctors_aux+0x18>
 80484a4:	83 c4 04             	add    $0x4,%esp
 80484a7:	5b                   	pop    %ebx
 80484a8:	5d                   	pop    %ebp
 80484a9:	c3                   	ret    
 80484aa:	90                   	nop
 80484ab:	90                   	nop

Disassembly of section .fini:

080484ac <_fini>:
 80484ac:	55                   	push   %ebp
 80484ad:	89 e5                	mov    %esp,%ebp
 80484af:	53                   	push   %ebx
 80484b0:	83 ec 04             	sub    $0x4,%esp
 80484b3:	e8 00 00 00 00       	call   80484b8 <_fini+0xc>
 80484b8:	5b                   	pop    %ebx
 80484b9:	81 c3 3c 1b 00 00    	add    $0x1b3c,%ebx
 80484bf:	e8 6c fe ff ff       	call   8048330 <__do_global_dtors_aux>
 80484c4:	59                   	pop    %ecx
 80484c5:	5b                   	pop    %ebx
 80484c6:	c9                   	leave  
 80484c7:	c3                   	ret
 

You can see that a implict cast in source code causes a substantial object code change.

分享到：
| gcov tutorial
评论
发表评论

您还没有登录,请您登录后再发表评论

相关推荐

    Universal-USB-Installer

    Source Code is made available at time of download, from the official UUI page: http://www.pendrivelinux.com/universal-usb-installer-easy-as-1-2-3/ IMPORTANT! No Warranty is being offered with this ...

    c# sample15个例子

    You may modify, copy, and distribute the source and object code form of the sample source code included in the subfolders of the project files. * Third Party Distribution. You may permit distributors...

    EhLib 8.0 Build 8.0.023 Pro Edition FullSource for D7-XE8

    Create new folder where source code and binary files will be kept (For example, C:\RAD_Studio_XE2\Components\EhLib). Hereinafter this folder will be call as "EhLib folder". Create new subfolder Lib ...

    NWH Vehicle Physics 1.7.2

    • C# source code with XML comments on all public members. • Tooltip explanations for all visible variables. Compatible With Complete Terrain Shader and IK Driver Vehicle Controller European Truck...

    Sakemail

    The default priority for each msg created will be prNormal, so you don‘t need to change your code any bit.1.8.6- Ulf Sturegren has added D4 compatibility, not many changes to the source (one letter)...

    EhLib 6.3 Build 6.3.176 Russian version. Full source included.

    EhLib 6.3 Build 6.3.176 Russian version....Create new folder where source code and binary files will be kept (For example, C:\RAD_Studio_XE2\Components\EhLib). Hereinafter this folder will be call as...

    VB编程资源大全（英文源码 其它）

    It will allow you to graphically design your message box, specify how you want it to look and will create the source code for you and put it into the clipboard where you &lt;END&gt;&lt;br&gt;47,vb2word.zip ...

    VB编程资源大全（英文源码 表单）

    Its a VB program with all source code and sample for creating a bspline / beziere curve / wireframe generator. Very good and fast code.&lt;END&gt;&lt;br&gt;43,reaction.zip A computer engineering student from ...

    WPTools.v6.29.1.Pro

    + to load old Hiedit templates as RTF code use the formatstring -HiEditFields. This will create merge fields for ALL fields. - NL sign was not shown right after CTRL+ENTER was pressed (requires ShowNL...

    delphi 7 gif控件

    // and it doesn't release the handle of the source bitmap which // // is used to assign to the GIF object as in gif.assign(bm); // // These changes were made as a result of a news post made by Renate ...

    VclZip pro v3.10.1

    Much faster processing due to linking to Zlib object files for compression and decompression routines. Blocked Zip Files (spanned zip archives split onto hard drive) - Now completely compatible ...

    Java邮件开发Fundamentals of the JavaMail API

    A general familiarity with object-oriented programming concepts and the Java programming language is necessary. The Java language essentials tutorial can help. copyright 1996-2000 Magelang ...

    BobBuilder_app

    Twitter Digg Facebook Del.icio.us Reddit Stumbleupon Newsvine Technorati Mr....Database » Database » Other databasesLicence...In v2.3 a single simple change of converting internal classes ...

    Bochs - The cross platform IA-32 (x86) emulator

    - Support more host OS to run on: - Include win64 native binary in the release. - Fixed failures on big endian hosts. - BIOS: Support for up to 2M ROM BIOS images. - GUI: select mouse capture toggle...

    微软内部资料-SQL性能优化3

    However, the req_mode column of master.dbo.syslockinfo has lock mode code that is one less than the code values shown here. For example, value of req_mode = 3 represents the Shared lock mode rather ...

    ehlib_vcl_src_9_3.26

    or on the external source (updating parameters [Params] and requiring data from DataDriver). Allows once-only (without the dynamic support) sort data, including Calculated and Lookup field. ...

    EhLib 9.1.024

    or on the external source (updating parameters [Params] and requiring data from DataDriver). Allows once-only (without the dynamic support) sort data, including Calculated and Lookup field. ...

    EurekaLog_7.5.0.0_Enterprise

    30)..Fixed: Leak of EurekaLog exception information object 31)..Fixed: Wrong chaining exceptions inside GetMem/FreeMem 32)..Fixed: Memory leak after low-level unhook of function 33)..Fixed: Re-...

    微软内部资料-SQL性能优化5

    The only source of any storage location information is the sysindexes table, which keeps track of the address of the root page for every index, and the first IAM page for the index or table....

    2009 达内Unix学习笔记

    集合了 所有的 Unix命令大全 ...telnet 192.168.0.23 自己帐号 sd08077-you0 ftp工具 192.168.0.202 tools-toolss ... 各个 shell 可互相切换 ksh:$ sh:$ csh:guangzhou% bash:bash-3.00$ ... 命令和参数之间必需用空格隔...

Magicbox
Global site tag (gtag.js) - Google Analytics