[lldb-dev] SBTarget::Launch return SBProcess with PID=0

Tue Apr 1 13:06:07 PDT 2014

On Apr 1, 2014, at 12:34 PM, Eran Ifrah <eran.ifrah at gmail.com> wrote:

> Thanks. I decided to debug it and see where it fails. So I built liblldb.3.5.0.dylib in debug mode and debugged the Launch function...
> 
> It turns out that it requires the debugserver and it assumes that it exists under LLDB.framework/
> however, I have no such directory within my cmake build :P
> 
> Now, "my" debugserver executable terminates immediately after execution:
> 
> $debugserver
> killed: 9
> $
> Running it under the debugger shows nothing significant (I will try to dig into this later also...)
> 
> However, if set this environment variable ( which I learnt about while debugging ) within codelite:
> LLDB_DEBUGSERVER_PATH=/Path/To/CommandLineTools/PrivateFrameworks/LLDB.framework/Resources/debugserver
> 
> The process launches successfully and I get a valid process ID (Hooray!)
> 
> 
> So a question to you guys:
> How do I create a framework out of the build?

Don't use cmake, use xcodebuild:

svn co ...
cd lldb
xcodebuild -configuration Release

Then in the build results will be in "./build/Release" and all needed executables will be in "./build/Release/LLDB.framework". The rpath for things linking against LLDB.framework is set be "@rpath/LLDB.framework/LLDB". So you will need to modify the LLDB plug-in that loads LLDB.framework to have a relative path to the LLDB.framework using linker flags ("Other Linker Flags" in your plug-in build, or "OTHER_LDFLAGS")

The lldb-tool in the Xcode project builds with multiple rpath linker settings:

-Wl,-rpath, at loader_path/../../Library/PrivateFrameworks/ 
-Wl,-rpath, at loader_path/../../../SharedFrameworks 
-Wl,-rpath, at loader_path/../../System/Library/PrivateFrameworks 
-Wl,-rpath, at loader_path/../../Library/PrivateFrameworks

@loader_path is the location of your codelight LLDB plug-in that needs to link against LLDB. The path can be relative and I would suggest you put a copy of LLDB.framework inside your codelight LLDB plugin bundle.

> Is this done manually? (i.e. should I simply create the directory structure and copy the relevant files to their respective location?)

No, let Xcode build the framework for you.

> Sorry for all the noobish questions, its just my OSX knowledge is very limited compared to Linux/Windows
> But I am working on it ;)

Just think of frameworks as the dylib + header files + any other files needed (debugserver, lldb-platform, and more) by the framework. It solves the issue of having to have multiple directories for includes (/usr/local/include/lldb), support files (/usr/local/lldb), and for the dylib (/usr/lib/liblldb.so) and keeps all files together and easily lets you have more than one LLDB.framework on your system without everyone having to fight over locations like "/usr/local/include/lldb".

> 
> P.S.
> This is how I built LLDB ( I am using the command line and not Xcode for that purpose) :
> 
> - svn checkout llvm
> - cd llvm/tools
> - svn checkout lldb
> - svn checkout clang
> - mkdir build-debug && cd build-debug
> - cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Debug
> - ninja
> 
> I also followed the signing process as described here http://llvm.org/svn/llvm-project/lldb/trunk/docs/code-signing.txt

On MacOSX, just download LLDB only and let LLDB build the llvm and clang it requires:

svn co http://llvm.org/svn/llvm-project/lldb/trunk lldb
cd lldb
xcodebuild -configuration Release

The build process will automagically download the right LLVM (into "lldb/llvm") and clang (into "lldb/llvm/tools/clang") and then build llvm and clang into a LLVM specific build folder ("lldb/llvm-build") for all required architectures (i386 and x86_64).

> 
> P.P.S
> I really hope that this mailing list is archived somewhere on the web so someone else who wishes to implement LLDB plugin for <choose the IDE name> will benefit for my noob questions

Anything that isn't clear from our "http://lldb.llvm.org/build.html" page should be updated. Feel free to suggest any improvements to these instructions.

The main problem you will run into is that you won't be able to distribute your "LLDB.framework" to others as the lldb_codesign is only valid for your machine. One thing you can do is to download the latest Xcode (5.1) from the AppStore and copy the /Applications/Xcode.app/Contents/SharedFrameworks/LLDB.framework/Resources/debugserver. It will contain a "debugserver" which is codesigned by Apple and won't run into the lldb_codesign issues on other MacOSX systems. "debugserver" is the only thing that requires the special code signing because it does the debugging and requires special privileges. So you can build the LLDB.framework and detailed above, then copy the debugserver from the latest Xcode release and place it into your LLDB.framework.

Greg

> 
> Thanks,
> Eran
> 
> 
> 
> 
> On Tue, Apr 1, 2014 at 9:43 PM, Greg Clayton <gclayton at apple.com> wrote:
> The easiest way to see what is going on is to enable gdb-remote packet logging. Make sure you tell Codelight to source the init files when you create your debugger:
> 
> // Init LLDB
> SBDebugger::Initialize();
> 
> // Create debugger
> bool source_init_files = true;
> SBDebugger debugger = SBDebugger::Create(source_init_files);
> 
> Then add the following line to your ~/.lldbinit file:
> 
> log enable -f /tmp/packets.txt gdb-remote packets
> 
> Then run and watch your pid come back with zero. Quit code light and attach the packets.txt file to a reply email and we can see what is going on.
> 
> Did you follow the code signing instructions? You might want to verify that your command line LLDB can indeed debug something:
> 
> % ./lldb /bin/ls
> (lldb) process launch
> 
> 
> Make sure it completes successfully.
> 
> 
> 
> On Apr 1, 2014, at 1:19 AM, Eran Ifrah <eran.ifrah at gmail.com> wrote:
> 
> > Hello,
> >
> > I have passed most of the barriers I had in order to integrate lldb within codeite and I have started testing the code on OSX.
> > I have OSX 10.9 and I compiled lldb (btw, an enforcement in CMake to ensure that Xcode is installed would be nice)
> > When I start debugging from within codelite using lldb, the call to m_target.Launch(...) where (m_target is of type SBTarget) returns a valid SBProcess, i.e. m_target.Launch().IsValid() is true
> >
> > However, calling m_target.GetProcess().GetProcessID() returns 0
> > Doing "ps -ef|grep TestLLDB" in the Terminal.app shows that the debuggee process was indeed launched ( I can confirm that the parent process is codelite)
> >
> > Any ideas why it may return 0?
> >
> > TIA,
> >
> > --
> > Eran Ifrah
> > Author of codelite, a cross platform open source C/C++ IDE: http://www.codelite.org
> > wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org
> > _______________________________________________
> > lldb-dev mailing list
> > lldb-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
> 
> 
> 
> 
> -- 
> Eran Ifrah
> Author of codelite, a cross platform open source C/C++ IDE: http://www.codelite.org
> wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org