java - Decompile C code with debug info? -


java , python byte code relatively easy decompile compiled machine code generated c/c++ compiler.

i unable find convincing answer why information -g option insufficient de-compilation, sufficient debugging? stuff contained in python/java byte code, makes decompilation easy?

i unable find convincing answer why information -g option insufficient de-compilation, sufficient debugging?

the debugging information contains mapping between addresses in generated code , source files line numbers. debugger not need decompile code - shows original sources. if source files missing, debugger won't magically show them.

that said, presence of debugging info make decompilation easier. if debug info includes layout of used types , function prototypes, decompiler can use , provide more precise decompilation. in many cases, however, still different original source.

for example, here's function decompiled hex-rays decompiler without using debug info:

int __stdcall sub_4050a0(int a1) {   int result; // eax@1    result = a1;   if ( *(_byte *)(a1 + 12) )   {     result = sub_404600(*(_dword *)a1);     *(_byte *)(a1 + 12) = 0;   }   return result; }

since not know type of a1, accesses fields represented additions , casts.

and here's same function after symbol file has been loaded:

void __thiscall mytree::write_page(mytree *this, page *src) {   if ( src->ischanged )   {     cache::set_changed(this->cache, src->baseaddr);     src->ischanged = 0;   } }

you can see it's been improved quite lot.

as why decompiling bytecode easier, in addition npe's answer check this.


Comments

Post a Comment

Popular posts from this blog

php - Wordpress website dashboard page or post editor content is not showing but front end data is showing properly -

Image
recently have uploaded wordpress site onto server. have uploaded wordpress site in sub-folder under root folder ../root(domain root folder)/wordpress (where host wordpress folder). now problem content data in page or post in dashboard of wordpress admin panel not showing - see image. but data showing in front view - see image. if not browser cache issue , not issue happened tinymce editor during upgrade; try add config file: define('concatenate_scripts', false);
Read more

How to get the ip address of VM and use it to configure SSH connection dynamically in Ansible -

i trying ip address of vm , trying use establish ssh vm. following script: --- - hosts: localhost become: yes connection: local gather_facts: false serial: 1 vars_files: - createvmvars.yml tasks: - name: gathering vm info. vsphere_guest: vcenter_hostname: "{{vcenter_hostname}}" username: "{{vcenter_username}}" password: "{{vcenter_password}}" guest: "{{guest_name}}" vmware_guest_facts: yes register: var - debug: msg="{{var.ansible_facts.hw_eth0.ipaddresses[0]}}" - name: establishing ssh connection. script: /home/shasha/devops/scripts/ssh_configure.sh "{{var.ansible_facts.hw_eth0.ipaddresses[0]}}" following content of ssh_configure.sh : #!/bin/sh ssh-keygen -t rsa ssh-copy-id $1 but when running playbook, getting following error while executing third task: error! 'var' undefined but debug module(second task) printin
Read more

javascript - Get parameter of GET request -

i make request: createxhrrequest( "get", fileurl, function( err, response ) { if( err ) { alert( "error get!" ); } alert(response); }); and full response: { "status" : "ok", "message" : "jvberi0xljqkjdduxdgkmy how can jvberi0xlj ? i try response.message , response["message"]. nothing works. just simple access this: var json = json.parse(response); json.message
Read more