[vlc-devel] Mac: Cannot get LLDB Symbols for libvlccore.dylib

[Marvin Scholz]

Hi,

On 15 Jan 2020, at 3:38, Sridhar Sarnobat wrote:

> *Issue*
>
> Cannot get lldb to print local variables for method
> src/playlist/control.c::playlist_vaControl() .
>

Sounds like you built VLC without debug symbols, when you call configure 
make
sure to add -g to the C, C++ and Objective-C compiler flags:

../extras/package/macosx/configure.sh […] CFLAGS="-g" CXXFLAGS="-g" 
OBJCFLAGS="-g"

>
> *Reproduction steps*
>
> cd vlc
>
> git checkout 8d432b0   # tag: 3.0.0-git
>
> # follow steps at MacOSCompile wiki page
>
>
> cd build/ \
>
> && PATH=/bin/:${PATH} make -j1
>
>
> lldb build/bin/vlc-osx-static
>
> (lldb) b playlist_vaControl
> Breakpoint 1: where = libvlccore.dylib`playlist_vaControl, address =
> 0x0000000000039130
>
> (lldb) run ~/trash/videos/201611070302_51.mp4 vlc://quit
>
> Process 82073 stopped
> * thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 
> 1.1
>     frame #0: 0x0000000100109130 libvlccore.dylib`playlist_vaControl
> libvlccore.dylib`playlist_vaControl:
> ->  0x100109130 <+0>:  pushq  %rbp
>     0x100109131 <+1>:  movq   %rsp, %rbp
>     0x100109134 <+4>:  subq   $0xa0, %rsp
>     0x10010913b <+11>: movb   %dl, %al
> Target 0: (vlc-osx-static) stopped.
>
> (lldb) p i_query
> error: use of undeclared identifier 'i_query'
>
>
> *Version info & other info*
>
> (-) git tag: 3.0.0-git
>
> (-) Source file:
> https://github.com/videolan/vlc/blob/3.0.0-git/src/playlist/control.c#L52
>
> (-) Mac OS X Mojave (10.14.6 (18G2022)) - but also my home laptop 
> whose
> version I don't have in front of me
>
> (-) Library compile info
>
>
> (lldb) image lookup -vn  playlist_vaControl
>
> 1 match found in 
> /Users/myusername/vlc/build/src/.libs/libvlccore.dylib:
>
>         Address: libvlccore.dylib[0x0000000000039130]
> (libvlccore.dylib.__TEXT.__text + 222784)
>
>         Summary: libvlccore.dylib`playlist_vaControl
>
>          Module: file =
> "/Users/myusername/vlc/build/src/.libs/libvlccore.dylib", arch = 
> "x86_64"
>
>          Symbol: id = {0x000001ef}, range =
> [0x0000000100109130-0x00000001001096f0), name="playlist_vaControl"
>
>
> (-) I have created vlc/build/bin/vlc-osx-static.dSYM but that doesn't 
> seem
> to be useful
>
>
>
> *End Goal*
>
> Create a simple VLC plugin using C (not Lua) which writes the "now 
> playing"
> media file out to /tmp/now_playing.txt
>
>
> *Notes*
>
> (-) I wish to use lldb for my code comprehension needs. Then I can 
> figure
> out how to write the code to fulfill my goal
>
>
> (-) I have never contributed to open source before, so please forgive 
> me if
> I am not following any etiquette.
>
> (-) I'm mainly a java developer, but have done a bit of GCC 
> development
> early in my career. Never CLang, and I'm not familiar with XCode and 
> would
> prefer command line (but am willing to use XCode if that's the only
> realistic option). I do have access to Ubuntu but would strongly 
> prefer Mac
> OS X initially (my Ubuntu machines are headless so would be headless, 
> and
> slower over ssh)
>
>
> (-) I do not wish to use Lua, mainly because I want to (re)aquaint 
> myself
> with C programming, but also I vaguely recall a limitation of Lua
> extensions that native modules do not have (but I could be wrong 
> about).
>
>
> (-) Thank you to all the people who created and maintain this, I've
> depended on it a lot so far and am pleasantly surprised it all works 
> :)
> https://wiki.videolan.org/MacOSCompile/
>
>
> Sridhar Sarnobat
> San Jose, CA 95128 | USA
> http://www.facebook.com/sridhar.sarnobat
> http://www.linkedin.com/in/sarnobat
> http://github.com/sarnobat
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