clang segfault - CXTypes.cpp:134

Clang Frontend
1

Hi all,

Using libclang with the python bindings to parse some header files and hopefully generate the equivalent Python ctypes definition for the structures requested.
After parse as I'm walking through the tree I am hitting a segfault in CXIndex.cpp:134 from struct2ctype.py:87
Looks like in CXTypes.cpp getCursorTU(C) returns null and freaks out on the next line where its dereferenced - Every valid cursor should have a valid TU right?
I've attach two files that can be used to reproduce the issue. Invoke with the following command

python2.7 struct2ctypes.py -d . StructName

I've had some mixed results reproducing the issue. With library I built from head I hit the issue having only parsed the single file but library shipped with ubuntu I need to place the file in a directory structure with plenty of other files.

My machine details
  - Linux 3.2.0-24-generic #39-Ubuntu SMP Mon May 21 16:52:17 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
  - Python 2.7.3 (default, Aug 1 2012, 05:14:39)
  - clang version 3.0

Happy to work further on this - just need some direction

Cheers,
Andrew

struct2ctype.tar (1.9 KB)

2

Could you please try reproducing this with Clang 3.2 or the latest SVN
version (http://clang.llvm.org/get_started.html)?

3

Hi Gregory,

I've tried with the a version I checked out from svn a week or so ago and still experience the segfault

LLVM
URL: http://llvm.org/svn/llvm-project/llvm/trunk
Repository Root: http://llvm.org/svn/llvm-project
Repository UUID: 91177308-0d34-0410-b5e6-96231b3b80d8
Revision: 171351
Node Kind: directory
Schedule: normal
Last Changed Author: ctopper
Last Changed Rev: 171351
Last Changed Date: 2013-01-02 07:53:20 +1100 (Wed, 02 Jan 2013)

Clang
URL: http://llvm.org/svn/llvm-project/cfe/trunk
Repository Root: http://llvm.org/svn/llvm-project
Repository UUID: 91177308-0d34-0410-b5e6-96231b3b80d8
Revision: 171351
Node Kind: directory
Schedule: normal
Last Changed Author: d0k
Last Changed Rev: 171350
Last Changed Date: 2013-01-02 07:08:10 +1100 (Wed, 02 Jan 2013)

Cheers,
Andrew

Quoting Gregory Szorc <gregory.szorc@gmail.com>:

4

Hi all,

Using libclang with the python bindings to parse some header files and hopefully generate the equivalent Python ctypes definition for the structures requested.
After parse as I'm walking through the tree I am hitting a segfault in CXIndex.cpp:134 from struct2ctype.py:87
Looks like in CXTypes.cpp getCursorTU(C) returns null and freaks out on the next line where its dereferenced - Every valid cursor should have a valid TU right?

Except on null/invalid cursors. I added a check in r172625 to make sure we don't crash if TU is null.

5

AFAIK every valid cursor should have a TU.

I tried running your code and could not trigger a segfault. I'm using Python 2.7.3 and an LLVM build from yesterday on OS X. Although, it sounds like you may have stumbled across a legit bug in libclang for the null TU. My realm of expertise is only Python. Hopefully someone else on this list will jump in... You should also consider filing a bug on this.

6

I should read my entire inbox before responding. Looks like r172625 fixed this.