[lldb-dev] [PATCH] For SBDebugger::Create assertion failure

[Matthew Gardiner]

The assertion failure in detail is this:

(gdb) bt
#0  0x0000003675e35c39 in raise () from /lib64/libc.so.6
#1  0x0000003675e37348 in abort () from /lib64/libc.so.6
#2  0x0000003675e2eb96 in __assert_fail_base () from /lib64/libc.so.6
#3  0x0000003675e2ec42 in __assert_fail () from /lib64/libc.so.6
#4  0x00007fd956ee1e29 in lldb_private::Debugger::Debugger
(this=0xd478f0, log_callback=0x0, baton=0x0)

at /home/mg11/src/main/devtools/main/llvm/tools/lldb/source/Core/Debugger.cpp:649
#5  0x00007fd956ee13a3 in lldb_private::Debugger::CreateInstance
(log_callback=0x0, baton=0x0)

at /home/mg11/src/main/devtools/main/llvm/tools/lldb/source/Core/Debugger.cpp:530
#6  0x00007fd9572456de in lldb::SBDebugger::Create
(source_init_files=0x1, callback=0x0, baton=0x0)

at /home/mg11/src/main/devtools/main/llvm/tools/lldb/source/API/SBDebugger.cpp:172
#7  0x00007fd95724560d in lldb::SBDebugger::Create
(source_init_files=0x1)

at /home/mg11/src/main/devtools/main/llvm/tools/lldb/source/API/SBDebugger.cpp:153
#8  0x00000000004008d8 in main () at main.cpp:10
(gdb) fr 4
#4  0x00007fd956ee1e29 in lldb_private::Debugger::Debugger
(this=0xd478f0, log_callback=0x0, baton=0x0)

at /home/mg11/src/main/devtools/main/llvm/tools/lldb/source/Core/Debugger.cpp:649
649	    assert (default_platform_sp.get());
(gdb) list
644	    if (log_callback)
645	        m_log_callback_stream_sp.reset (new StreamCallback
(log_callback, baton));
646	    m_command_interpreter_ap->Initialize ();
647	    // Always add our default platform to the platform list
648	    PlatformSP default_platform_sp (Platform::GetHostPlatform());
649	    assert (default_platform_sp.get());
650	    m_platform_list.Append (default_platform_sp, true);
651	    
652	    m_collection_sp->Initialize (g_properties);
653	    m_collection_sp->AppendProperty (ConstString("target"),
(gdb) 



On Fri, 2014-10-03 at 13:46 +0100, Matthew Gardiner wrote:

> Hi folks,
> 
> Whilst starting to play with the lldb C++ API, I've noticed that this
> simple little program causes an assertion failure (and hence a core
> dump).
> 
> #include <cstdio>
> #include "lldb/API/LLDB.h"
> 
> int main()
> {
>     fprintf(stderr, "lldb-app\n");
> //  lldb::SBDebugger::Initialize();
>     lldb::SBDebugger dbgr = lldb::SBDebugger::Create(true);
>     fprintf(stderr, "SBDebugger::Create!\n");
>     return 0;
> }
> 
> As guessed, by uncommenting out the Initialize call, the assertion is
> satisfied by Create and friends, and the code runs to completion.
> 
> To me, this is bad on 2 counts:
> 
> 1. If Create depends on Initialize then Initialize should be called
> internally.
> 2. From a public API perspective, even if Create and Initialize need to
> be called separately, a crash (failed assert) seems a little harsh.
> Shouldn't an error return (or exception throw) be used to communicate
> the user's mistake in this case?
> 
> I did some digging into SBDebugger::Initialize and it seems safe for
> this to be called internally by Create.
> 
> So I'm proposing that I fix this issue with following patch:
> 
> Index: source/API/SBDebugger.cpp
> ===================================================================
> --- source/API/SBDebugger.cpp	(revision 218974)
> +++ source/API/SBDebugger.cpp	(working copy)
> @@ -159,6 +159,8 @@
>  {
>      Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_API));
>  
> +    Initialize();
> +
>      SBDebugger debugger;
>      
>      // Currently we have issues if this function is called
> simultaneously on two different
> @@ -210,6 +212,8 @@
>                       sstr.GetData());
>      }
>  
> +    Terminate();
> +
>      Debugger::Destroy (debugger.m_opaque_sp);
>  
>      if (debugger.m_opaque_sp.get() != NULL)
> 
> 
> Please shout out if you don't want me to.
> 
> thanks
> Matt
> 
> 
> 
> 
> Member of the CSR plc group of companies. CSR plc registered in England and Wales, registered number 4187346, registered office Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, United Kingdom
> More information can be found at www.csr.com. Keep up to date with CSR on our technical blog, www.csr.com/blog, CSR people blog, www.csr.com/people, YouTube, www.youtube.com/user/CSRplc, Facebook, www.facebook.com/pages/CSR/191038434253534, or follow us on Twitter at www.twitter.com/CSR_plc.
> New for 2014, you can now access the wide range of products powered by aptX at www.aptx.com.
> _______________________________________________
> lldb-dev mailing list
> lldb-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
> 
> 
>  To report this email as spam click https://www.mailcontrol.com/sr/pilrSd6CXBDGX2PQPOmvUj!GOBh06pKKo4kkp2B6Y080nTmNNKVHT4SNd1RosIFWqz8LAxcsry5jDxGYc2QXWA== .


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/lldb-dev/attachments/20141003/ccb2fc22/attachment.html>