It sounds like the .debug_aranges section the compiler is generating is not 
correct, and that is what is messing everything up. If we have a .debug_aranges 
section, we use it. If it is missing, then we auto generate it by pulling in 
all DWARF and calculating it by hand. This is bad because it consumes time and 
memory to pull in all DWARF just to generate the address ranges.

File a bug against clang with your repro steps.

Greg

On Aug 8, 2013, at 8:21 AM, Kal Conley <[email protected]> wrote:

> I figured out how to reproduce this. Just compile with clang 
> -fsanitize=address any program and you should see what I am seeing.
> -Kal
> 
> 
> 2013/8/8 Kal Conley <[email protected]>
> I am not able to post the source/binary of this inferior. I built it with 
> clang-3.4. If I build with g++4.7 lldb loads the source information 
> correctly, so this may be a clang bug if you think the generated dwarf info 
> is wrong. On the other hand gdb does handle this binary without a problem.
> -Kal
> 
> 
> 2013/8/8 Malea, Daniel <[email protected]>
> 
> Hmm, what compiler/version are you using to build the inferior you are trying 
> to debug? Any chance you can file a bug at llvm.org/bugs and attach the 
> problematic binary?
> 
> Thanks,
> Dan
> 
> From: Kal Conley <[email protected]>
> Date: Thursday, 8 August, 2013 8:03 AM
> To: Andrew Kaylor <[email protected]>
> Cc: "[email protected]" <[email protected]>, Daniel Malea 
> <[email protected]>
> 
> Subject: Re: [lldb-dev] lldb problems on linux
> 
> If I apply the following to ignore .debug_aranges source debugging works 
> again:
> 
> Index: source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.cpp
> ===================================================================
> --- source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.cpp    (Revision 187863)
> +++ source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.cpp    (Arbeitskopie)
> @@ -58,7 +58,7 @@
>  
>          m_cu_aranges_ap.reset (new DWARFDebugAranges());
>          const DataExtractor &debug_aranges_data = 
> m_dwarf2Data->get_debug_aranges_data();
> -        if (debug_aranges_data.GetByteSize() > 0)
> +        if (0 && debug_aranges_data.GetByteSize() > 0)
>          {
>              if (log)
>                  log->Printf ("DWARFDebugInfo::GetCompileUnitAranges() for 
> \"%s\" from .debug_aranges",
> 
> 
> 
> 2013/8/8 Kal Conley <[email protected]>
> I enabled logging... I am seeing this when I run
> (lldb) b main.cc:14
> 
> <... Lots of other info ...>
> main-thread Address            Line   Column File   ISA Flags
> main-thread ------------------ ------ ------ ------ --- -------------
> main-thread 0x00000000004afa70      8      0      1   0  is_stmt
> main-thread 0x00000000004afd2e     14      0      1   0  is_stmt prologue_end
> main-thread 0x00000000004afd69     16      0      1   0  is_stmt
> main-thread 0x00000000004afd94     20      0      1   0  is_stmt
> main-thread 0x00000000004afda3     23      0      1   0  is_stmt
> main-thread 0x00000000004afe6c     24      0      1   0  is_stmt
> main-thread 0x00000000004b017b     24      0      1   0  is_stmt end_sequence
> main-thread 0x00000000004b0180   2292      0      2   0  is_stmt
> main-thread 0x00000000004b02b3   2292      0      2   0  is_stmt prologue_end
> main-thread 0x00000000004b0322   2292      0      2   0  is_stmt end_sequence
> main-thread 0x00000000004b0330    494      0     78   0  is_stmt
> main-thread 0x00000000004b0409    494      0     78   0  is_stmt prologue_end
> main-thread 0x00000000004b04a1    494      0     78   0  is_stmt end_sequence
> main-thread 0x00000000004b04b0   2292      0      2   0  is_stmt
> main-thread 0x00000000004b05e3   2292      0      2   0  is_stmt prologue_end
> main-thmain-thread DWARFDebugInfo::GetCompileUnitAranges() for 
> "/home/kal/test/test" from .debug_aranges
> main-thread DWARFDebugAranges::Sort(minimize = 1) with 23 entriesread 
> 0x00000000004b0671   2292      0      2   0  is_stmt end_sequence
> main-thread DWARFDebugAranges::Sort() 11 entries after minimizing (12 entries 
> combined for 192 bytes saved)
> main-thread 0x00000000: [0x45d670 - 0x45d7a4)
> main-thread 0x00021392: [0x45d7b0 - 0x45d7be)
> main-thread 0x00000000: [0x45dbf0 - 0x465c0c)
> main-thread 0x0001d8d4: [0x465c10 - 0x467120)
> main-thread 0x00021392: [0x467120 - 0x468172)
> main-thread 0x0002429a: [0x468180 - 0x485d9c)
> main-thread 0x0005cd35: [0x485da0 - 0x485e1f)
> main-thread 0x0005dd15: [0x485e20 - 0x4865e5)
> main-thread 0x0005fff2: [0x4865f0 - 0x486b7c)
> main-thread 0x00061b4e: [0x486b80 - 0x487eff)
> main-thread 0x00064a9d: [0x487f00 - 0x488295)
> Breakpoint 1: no locations (pending).
> WARNING:  Unable to resolve breakpoint to any actual locations.
> 
> The address 0x00000000004afd2e for line 14 is correct. If i run "b main" I 
> also get there. But that address isn't in the Aranges list.
> -Kal
> 
> 
> 2013/8/7 Kaylor, Andrew <[email protected]>
> 
> I agree that logging is the best place to start.  Without a better idea of 
> what’s failing, it’s hard to say where to start.
> 
>  
> 
> You could try something like setting a breakpoint in the 
> CommandObjectBreakpointSet::DoExecute() function, and stepping through from 
> there.  I think that’s likely to get you to the beginning of the DWARF 
> processing if setting a breakpoint is the first thing you do after creating 
> the target (or specifying it on the command line).  It’s a long and winding 
> road from there to the meaty bits, but without some hints from the log output 
> it’s hard to say where a wrong turn might have been taken.
> 
>  
> 
> SymbolFileDWARF::ParseCompileUnit() is another potentially interesting 
> starting place, but I think there’s a good chance you won’t get there if you 
> aren’t seeing any source information.
> 
>  
> 
> -Andy
> 
>  
> 
> From: Malea, Daniel 
> Sent: Wednesday, August 07, 2013 1:14 PM
> To: Kal Conley
> Cc: Kaylor, Andrew; [email protected]
> 
> 
> Subject: Re: [lldb-dev] lldb problems on linux
> 
>  
> 
> Enabling logging is probably a good first place to start. If you're not 
> seeing source information, then maybe lldb is unable to parse some stuff that 
> clang is generating… to see what the DWARF parser is doing, you can:
> 
>  
> 
> (lldb) log enable dwarf all
> 
>  
> 
> There's many logging categories that can be enabled; some are quite 
> verbose..to see all of them, do:
> 
>  
> 
> (lldb) log list
> 
>  
> 
> Also, with the '-f' option, you can dump the output to a file for easier 
> perusal.
> 
>  
> 
>  
> 
> Cheers,
> 
> Dan
> 
>  
> 
> From: Kal Conley <[email protected]>
> Date: Wednesday, 7 August, 2013 2:44 PM
> To: Daniel Malea <[email protected]>
> Cc: Andrew Kaylor <[email protected]>, "[email protected]" 
> <[email protected]>
> Subject: Re: [lldb-dev] lldb problems on linux
> 
>  
> 
> I am still seeing issues with source-level debugging. "target modules dump 
> sections" has symbol entries. Also source level debugging is working in gdb, 
> so I know that symbols are available.
> The strange thing is, I tried the same thing with a simple "Hello world" 
> program and source level debugging worked. Both programs are being compiled 
> with clang-3.4.
> 
> Can someone give me a tip where I can should put breakpoints in LLDB to debug 
> this?
> 
> Thanks,
> -Kal
> 
> Am 8/7/13 12:04 AM, schrieb Kal Conley:
> 
> Hi Dan,
> Sorry I wasn't clear. My fix fixes the test suite issue. The only remaining 
> issue is the source debugging issue. I haven't got to look into that yet. I 
> am on Debian Wheezy.
> -Kal
> 
> Am 8/6/13 11:44 PM, schrieb Malea, Daniel:
> 
> Thank you Kal for the fix! Much appreciated :)
> 
>  
> 
> I committed it in r187818.
> 
>  
> 
> So, just to clarify, you're still unable to run the test suite after the fix? 
> Which distro are you on?
> 
>  
> 
>  
> 
> Thanks,
> 
> Dan
> 
>  
> 
> From: Kal Conley <[email protected]>
> Date: Tuesday, 6 August, 2013 5:27 PM
> To: Andrew Kaylor <[email protected]>, "[email protected]" 
> <[email protected]>
> Subject: Re: [lldb-dev] lldb problems on linux
> 
>  
> 
> Hi Andy,
> So I figured out the python issue. Host::GetLLDBPath() is broken. It was 
> failing for me because I am building in Release mode. It only works in Debug 
> mode by luck :) The problem is lines 1035+ in source/Host/common/Host.cpp. 
> llvm::Twine should only be used for temporary objects! See 
> http://llvm.org/docs/ProgrammersManual.html#dss-twine
> 
> I have attached a patch this fixes the issue. I haven't found time to 
> investigate my other issue yet.
> 
> Thanks!
> -Kal
> 
> Am 8/6/13 4:29 PM, schrieb Kaylor, Andrew:
> 
> Hmm…  I’ve never seen the -P option print the wrong path.  Looking at the 
> code (in Host::GetLLDBPath) it doesn’t even look possible for it to print 
> what you’re seeing.
> 
>  
> 
> On the other hand, the second directory you mention should be the correct 
> one.  If you set PYTHONPATH to that does “python -c ‘import lldb’” work?
> 
>  
> 
> -Andy
> 
>  
> 
> From: Kal Conley [mailto:[email protected]] 
> Sent: Tuesday, August 06, 2013 2:00 AM
> To: Kaylor, Andrew
> Cc: [email protected]
> Subject: Re: [lldb-dev] lldb problems on linux
> 
>  
> 
> Hi Andy,
> I tried
> export PYTHONPATH=`$llvm/build/Debug+Asserts/bin/lldb -P`
> but it didn't work for me. If I run `build/bin/lldb -P` it outputs 
> "build/lib7/site-packages" which doesn't exist.
> There is a directory build/lib/python-2.7/site-packages but if I set the 
> PYTHONPATH to this directory I get the same errors.
> 
> I can import lldb; in python successfully though.
> 
> Any other ideas?
> 
> -Kal
> 
>  
> 
> 2013/8/5 Kaylor, Andrew <[email protected]>
> 
> Hi Kal,
> 
>  
> 
> For the second problem, you need to set the PYTHONPATH environment variable.  
> Try this:
> 
>  
> 
> export PYTHONPATH=`$llvm/build/Debug+Asserts/bin/lldb -P`
> 
>  
> 
> Regarding the source information, I would start by using the following 
> command within lldb (after you have created the target you want to debug):
> 
>  
> 
> target modules dump sections
> 
>  
> 
> If you don’t see debug sections in that list, then that’s the problem.  If 
> you do, try enabling DWARF logging (‘log enable dwarf all’) and see if 
> anything obvious turns up in the output when you try to set a breakpoint.
> 
>  
> 
> -Andy
> 
>  
> 
> From: [email protected] [mailto:[email protected]] On 
> Behalf Of Kal Conley
> Sent: Sunday, August 04, 2013 11:27 AM
> To: [email protected]
> 
> 
> Subject: [lldb-dev] lldb problems on linux
> 
>  
> 
> Hi,
> 
> I recently build lldb from trunk (revision 187708) and source-level debugging 
> isn't working for me. It seems its not loading any source information. What 
> is the best way to troubleshoot this?
> 
> Also make check-lldb doesn't work on Linux when building with CMake. I just 
> get error:
> 
> This script requires lldb.py to be in either 
> /home/user/tools/llvm_3.4~svn187708/tools/lldb/build/Debug/LLDB.framework/Resources/Python,
>  
> /home/user/tools/llvm_3.4~svn187708/tools/lldb/build/Release/LLDB.framework/Resources/Python,
>  or 
> /home/user/tools/llvm_3.4~svn187708/tools/lldb/build/BuildAndIntegration/LLDB.framework/Resources/Python
> 
> I get the same error with lldb-3.3.
> 
>  
> 
> Thanks!
> 
>  
> 
>  
> 
>  
> 
>  
> 
> 
> 
> 
> 
> _______________________________________________
> lldb-dev mailing list
> [email protected]
> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev


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